ORCID Profile
0000-0002-6207-1889
Current Organisation
Australian Regenerative Medicine Institute
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Developmental Genetics (incl. Sex Determination) | Genetics | Neurogenetics | Cell Development, Proliferation and Death
Neurodegenerative Disorders Related to Ageing | Expanding Knowledge in the Biological Sciences | Cardiovascular System and Diseases | Nervous System and Disorders |
Publisher: Wiley
Date: 07-2003
DOI: 10.1046/J.1471-4159.2003.01850.X
Abstract: The functional role of histamine (HA) in zebrafish brains was studied. Zebrafish did not display a clear circadian variation in brain HA levels. Loading of zebrafish with l-histidine increased HA concentration in the brain. A single injection of the histidine decarboxylase (HDC) inhibitor, alpha-fluoromethylhistidine (alpha-FMH), gave rise to a rapid reduction in zebrafish brain HA. Low HDC activity in the brain after injections verified the effect of alpha-FMH. A reduction in the number of histaminergic fibres but not neurones and an increased expression of HDC mRNA was evident after alpha-FMH. Automated behavioural analysis after alpha-FMH injection showed no change in swimming activity, but abnormalities were detected in exploratory behaviour examined in a circular tank. No significant behavioural changes were detected after histidine loading. The time spent for performance in the T-maze was significantly increased in the first trial 4 days after alpha-FMH injections, suggesting that lack of HA may impair long-term memory. The rostrodorsal telencephalon, considered to correspond to the mammalian amygdala and hippoc us in zebrafish, is densely innervated by histaminergic fibres. These results suggest that low HA decreases anxiety and/or affects learning and memory in zebrafish, possibly through mechanisms that involve the dorsal forebrain.
Publisher: MyJove Corporation
Date: 23-05-2013
DOI: 10.3791/50415
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2242824
Publisher: Elsevier BV
Date: 06-1998
Publisher: Cold Spring Harbor Laboratory
Date: 09-02-2018
DOI: 10.1101/262162
Abstract: Alzheimer’s disease (AD) develops silently over decades. We cannot easily access and analyse pre-symptomatic brains, so the earliest molecular changes that initiate AD remain unclear. Previously, we demonstrated that the genes mutated in early-onset, dominantly-inherited familial forms of AD (fAD) are evolving particularly rapidly in mice and rats. Fortunately, some non-mammalian vertebrates such as the zebrafish preserve fAD-relevant transcript isoforms of the PRESENILIN ( PSEN1 and PSEN2 ) genes that these rodents have lost. Zebrafish are powerful vertebrate genetic models for many human diseases, but no genetic model of fAD in zebrafish currently exists. We edited the zebrafish genome to model the unique, protein-truncating fAD mutation of human PSEN2 , K115fs. Analysing the brain transcriptome and proteome of young (6-month-old) and aged, infertile (24-month-old) wild type and heterozygous fAD-like mutant female sibling zebrafish supports accelerated brain aging and increased glucocorticoid signalling in young fAD-like fish, leading to a transcriptional ‘inversion’ into glucocorticoid resistance and vast changes in biological pathways in aged, infertile fAD-like fish. Notably, one of these changes involving microglia-associated immune responses regulated by the ETS transcription factor family is preserved between our zebrafish fAD model and human early-onset AD. Importantly, these changes occur before obvious histopathology and likely in the absence of Aβ. Our results support the contributions of early metabolic and oxidative stresses to immune and stress responses favouring AD pathogenesis and highlight the value of our fAD-like zebrafish genetic model for elucidating early changes in the brain that promote AD pathogenesis. The success of our approach has important implications for future modelling of AD.
Publisher: Wiley
Date: 09-01-2009
DOI: 10.1111/J.1471-4159.2008.05793.X
Abstract: Larval zebrafish offers a good model to approach brain disease mechanisms, as structural abnormalities of their small brains can be correlated to quantifiable behavior. In this study, the structural alterations in one diencephalic dopaminergic nucleus induced by 1-methyl-4-phenylpyridinium (MPP+), a toxin inducing Parkinson's disease in humans, and those found in several neuronal groups after 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), the pretoxin, were associated with decreased swimming speed. Detailed cell counts of dopaminergic groups indicated a transient decline of tyrosine hydroxylase expressing neurons up to about 50% after MPTP. The MPTP effect was partly sensitive to monoamine oxidase inhibitor deprenyl. Detailed analysis of the developing catecholaminergic cell groups suggests that the cell groups emerged at their final positions and no obvious significant migration from the original positions was seen. One 5-HT neuron group was also affected by MPTP treatment, whereas other groups remained intact, suggesting that the effect is selective. New nomenclature for developing catecholaminergic cell groups corresponding to adult groups is introduced. The diencephalic cell population consisting of groups 5,6 and 11 was sensitive to both MPTP and MPP+ and in this respect resembles mammalian substantia nigra. The results suggest that MPTP and MPP+ induce a transient functional deficit and motility disorder in larval zebrafish.
Publisher: Elsevier BV
Date: 07-2006
DOI: 10.1016/J.YDBIO.2006.03.040
Abstract: Lifelong neurogenesis in vertebrates relies on stem cells producing proliferation zones that contain neuronal precursors with distinct fates. Proliferation zones in the adult zebrafish brain are located in distinct regions along its entire anterior-posterior axis. We show a previously unappreciated degree of conservation of brain proliferation patterns among teleosts, suggestive of a teleost ground plan. Pulse chase labeling of proliferating populations reveals a centrifugal movement of cells away from their places of birth into the surrounding mantle zone. We observe tangential migration of cells born in the ventral telencephalon, but only a minor rostral migratory stream to the olfactory bulb. In contrast, the lateral telencephalic area, a domain considered homologous to the mammalian dentate gyrus, shows production of interneurons and migration as in mammals. After a 46-day chase, newborn highly mobile cells have moved into nuclear areas surrounding the proliferation zones. They often show HuC/D immunoreactivity but importantly also more specific neuronal identities as indicated by immunoreactivity for tyrosine hydroxylase, serotonin and parvalbumin. Application of a second proliferation marker allows us to recognize label-retaining, actively cycling cells that remain in the proliferation zones. The latter population meets two key criteria of neural stem cells: label retention and self renewal.
Publisher: SPIE
Date: 09-12-2016
DOI: 10.1117/12.2242828
Publisher: MDPI AG
Date: 08-03-2018
DOI: 10.3390/MI9030116
Publisher: The Company of Biologists
Date: 03-2022
DOI: 10.1242/DMM.049094
Abstract: Cyclin-dependent kinase-like-5 (CDKL5) deficiency disorder (CDD) is a severe X-linked neurodegenerative disease characterised by early-onset epileptic seizures, low muscle tone, progressive intellectual disability and severe motor function. CDD affects ∼1 in 60,000 live births, with many patients experiencing a reduced quality of life due to the severity of their neurological symptoms and functional impairment. There are no effective therapies for CDD, with current treatments focusing on improving symptoms rather than addressing the underlying causes of the disorder. Zebrafish offer many unique advantages for high-throughput preclinical evaluation of potential therapies for neurological diseases, including CDD. In particular, the large number of offspring produced, together with the possibilities for in vivo imaging and genetic manipulation, allows for the detailed assessment of disease pathogenesis and therapeutic discovery. We have characterised a loss-of-function zebrafish model for CDD, containing a nonsense mutation in cdkl5. cdkl5 mutant zebrafish display defects in neuronal patterning, seizures, microcephaly, and reduced muscle function caused by impaired muscle innervation. This study provides a powerful vertebrate model for investigating CDD disease pathophysiology and allowing high-throughput screening for effective therapies. This article has an associated First Person interview with the first author of the paper.
Publisher: Springer Science and Business Media LLC
Date: 22-12-2018
DOI: 10.1007/S12020-017-1502-3
Abstract: Type 1 and 2 diabetes are characterized by a loss of insulin-producing beta-cells. Current treatments help maintain blood glucose levels but cannot provide a cure. As such, a vital target for the cure of diabetes is a way to restore beta-cell mass. The drug metformin can protect cultured beta-cells/islets from hyperglycemia-induced dysfunction and death. Further, treatment of pregnant mice with metformin results in an enhanced beta-cell fraction in the embryos however, whether this occurs via a direct effect is unknown. We utilized the external embryogenesis of the zebrafish to determine the direct effect of metformin treatment on the pancreas of the developing embryo and following beta-cell ablation. During development metformin did not alter beta-cell or alpha-cell mass but had a small effect to increase delta-cell mass as measured by in situ hybridization. Further metformin significantly increased beta-cell number. Following beta-cell ablation, both glucagon and somatostatin expression were upregulated (>2-fold). Additionally, while metformin showed no effect to alter beta-cell mass or number, somatostatin expression was further increased (>5-fold). We showed that direct exposure to metformin during embryogenesis does not increase insulin-expressing area but does increase beta-cell number. Further, we identified novel consequences of beta-cell ablation to alter the expression of other pancreatic hormones that were enhanced by metformin. Therefore, this study provides a greater understanding of the beta-cell development/regenerative processes and the effect of metformin, bringing us closer to identifying how to increase beta-cells in humans.
Publisher: Wiley
Date: 10-2005
DOI: 10.1111/J.1460-9568.2005.04387.X
Abstract: Among the well-established roles of the neurotransmitter histamine (HA) is that as a regulator of the sleep-wake cycle, which early gained HA a reputation as a 'waking substance'. The tuberomammillary nucleus (TMN) of the posterior hypothalamus, which contains the sole source of neuronal HA in the brain, is reciprocally connected to the suprachiasmatic nucleus (SCN) which, in turn, is best known as the pacemaker of circadian rhythms in mammals. We report HA-immunoreactive (-ir) neurons in the mouse and rat SCN that neither display immunoreactivity (-iry) for the HA-synthesizing enzyme histidine decarboxylase (HDC) nor contain HDC mRNA. Further, HA-iry was absent in the SCN of HDC knockout mice, but present in appropriate control animals, indicating that the observed HA-iry is HDC dependent. Experiments with hypothalamic slice cultures and i.c.v. injection of HA suggest that HA in the SCN neurons originates in the TMN and is transported from the TMN along histaminergic fibres known to innervate the SCN. These results could indicate the existence of a hitherto unknown uptake mechanism for HA into neurons. Through HA uptake and, putatively, re-release of the captured HA, these neurons could participate in the HA-mediated effects on the circadian system in concert with direct histaminergic inputs from the TMN to the SCN. The innervation of the SCN by several neurotransmitter systems could provide a way for other systems to affect the HA-containing neuronal cell bodies in the SCN.
Publisher: Wiley
Date: 13-12-2011
DOI: 10.1002/CNE.22757
Abstract: The morphology of the telencephalon displays great ersity among different vertebrate lineages. Particularly the everted telencephalon of ray-finned fishes shows a noticeably different morphology from the evaginated telencephalon of nonray-finned fishes and other vertebrates. This makes the comparison between the different parts of the telencephalon of ray-finned fishes and other vertebrates difficult. Based on neuroanatomical, neurochemical, and connectional data no consensus on the sub isions of the adult telencephalon of ray-finned fishes and their relation to nuclei in the telencephalon of other vertebrates has been reached yet. For tetrapods, comparative expression pattern analysis of homologous developmental genes has been a successful approach to clarify homologies between different parts of the telencephalon. In the larval zebrafish, sub isions of the subpallium have been proposed using conserved developmental gene expression. In this study, we investigate the sub isions of the adult zebrafish telencephalon by analyzing the expression pattern of conserved molecular marker genes. We identify the boundary between the pallium and subpallium based on the complementary expression of dlx2a, dlx5a in the subpallium and tbr1, neurod in the pallium. Furthermore, combinatorial expression of Isl, nkx2.1b, lhx1b, tbr1, eomesa, emx1, emx2, and emx3 identifies striatal-like, pallidal-like, and septal-like sub isions within the subpallium. In contrast to previous models, we propose that the striatum and pallidum are stretched along the rostrocaudal axis of the telencephalon. Further, the septal nuclei derive from both the pallium and subpallium. On this basis, we present a new model for the sub isions of the subpallium in teleost fish.
Publisher: Elsevier
Date: 1998
Publisher: SPIE
Date: 06-2015
DOI: 10.1117/12.2180691
Publisher: Springer Science and Business Media LLC
Date: 11-03-2019
DOI: 10.1038/S41598-019-41009-3
Abstract: Maternal hyperglycaemia has a profound impact on the developing foetus and increases the risk of developing abnormalities like obesity, impaired glucose tolerance and insulin secretory defects in the post-natal life. Increased levels of glucose in the blood stream due to diabetes causes visual disorders like retinopathy. However, the impact of maternal hyperglycaemia due to pre-existing or gestational diabetes on the developing foetal retina is unknown. The aim of this work was to study the effect of hyperglycaemia on the developing retina using zebrafish as a vertebrate model. Wild-type and transgenic zebrafish embryos were exposed to 0, 4 and 5% D-Glucose in a pulsatile manner to mimic the fluctuations in glycaemia experienced by the developing foetus in pregnant women with diabetes. The zebrafish embryos displayed numerous ocular defects associated with altered retinal cell layer thickness, increased presence of macrophages, and decreased number of Müeller glial and retinal ganglion cells following high-glucose exposure. We have developed a model of gestational hyperglycaemia using the zebrafish embryo to study the effect of hyperglycaemia on the developing embryonic retina. The data suggests that glucose exposure is detrimental to the development of embryonic retina and the legacy of this exposure may extend into adulthood. These data suggest merit in retinal assessment in infants born to mothers with pre-existing and gestational diabetes both in early and adult life.
Publisher: MDPI AG
Date: 12-08-2022
DOI: 10.3390/IJMS23168990
Abstract: Due to increasing numbers of anthropogenic chemicals with unknown neurotoxic properties, there is an increasing need for a paradigm shift toward rapid and higher throughput behavioral bioassays. In this work, we demonstrate application of a purpose-built high throughput multidimensional behavioral test battery on larval stages of Danio rerio (zebrafish) at 5 days post fertilization (dpf). The automated battery comprised of the established spontaneous swimming (SS), simulated predator response (SPR), larval photomotor response (LPR) assays as well as a new thermotaxis (TX) assay. We applied the novel system to characterize environmentally relevant concentrations of emerging pharmaceutical micropollutants including anticonvulsants (gabapentin: 400 ng/L carbamazepine: 3000 ng/L), inflammatory drugs (ibuprofen: 9800 ng/L), and antidepressants (fluoxetine: 300 ng/L venlafaxine: 2200 ng/L). The successful integration of the thermal preference assay into a multidimensional behavioral test battery provided means to reveal ibuprofen-induced perturbations of thermal preference behaviors upon exposure during embryogenesis. Moreover, we discovered that photomotor responses in larval stages of fish are also altered by the as yet understudied anticonvulsant gabapentin. Collectively our results demonstrate the utility of high-throughput multidimensional behavioral ecotoxicity test batteries in prioritizing emerging risks associated with neuroactive drugs that can perturb neurodevelopment. Moreover, we showcase the added value of thermotaxis bioassays for preliminary screening of emerging contaminants.
Publisher: The Company of Biologists
Date: 15-11-2011
DOI: 10.1242/DEV.072587
Abstract: Severe traumatic injury to the adult mammalian CNS leads to life-long loss of function. By contrast, several non-mammalian vertebrate species, including adult zebrafish, have a remarkable ability to regenerate injured organs, including the CNS. However, the cellular and molecular mechanisms that enable or prevent CNS regeneration are largely unknown. To study brain regeneration mechanisms in adult zebrafish, we developed a traumatic lesion assay, analyzed cellular reactions to injury and show that adult zebrafish can efficiently regenerate brain lesions and lack permanent glial scarring. Using Cre-loxP-based genetic lineage-tracing, we demonstrate that her4.1-positive ventricular radial glia progenitor cells react to injury, proliferate and generate neuroblasts that migrate to the lesion site. The newly generated neurons survive for more than 3 months, are decorated with synaptic contacts and express mature neuronal markers. Thus, regeneration after traumatic lesion of the adult zebrafish brain occurs efficiently from radial glia-type stem rogenitor cells.
Publisher: Springer Science and Business Media LLC
Date: 05-2004
Publisher: AIP Publishing
Date: 11-2015
DOI: 10.1063/1.4939031
Abstract: Additive manufacturing was adopted in multiple fields of life sciences. It is also becoming a popular tool for rapid prototyping of microfluidic and biomedical devices. Limited studies have been performed to investigate the biological implications of using 3D printed polymers. Here we assessed the biocompatibility of seven commercially available polymers, using a battery of standardized bioassays for chemical risk assessment. Our data show that leachates from photopolymers substrata appear to be very toxic to vertebrates and several invertebrate indicator organisms. These results demonstrate significant consequences for the use of selected photopolymers in the fabrication of bio-devices.
Publisher: Elsevier BV
Date: 03-2018
Publisher: Frontiers Media SA
Date: 17-01-2018
Publisher: American Chemical Society (ACS)
Date: 03-08-2021
Publisher: Cold Spring Harbor Laboratory
Date: 23-05-2017
DOI: 10.1101/140608
Abstract: LRRK2 mutations are a major cause of Parkinson’s disease. Pathogenicity of LRRK2 loss-of-function is controversial, as knockout in rodents reportedly induces no brain-specific effects and knockdown studies in zebrafish are conflicting. Here we show that CRISPR/Cas9-engineered deletion of the ~60-kbp-long zebrafish lrrk2 locus elicits a pleomorphic, albeit transient brain phenotype in maternal-zygotic mutants (mzLrrk2). Intriguingly, 11-month-old mzLrrk2 adults display increased dopamine and serotonin catabolism. Additionally, we find decreased mitosis in the larval brain and reduced stab injury-induced neuronal regeneration in the adult telencephalon. Finally, hypokinesia associates with loss of lrrk2 in larvae. Our results demonstrate that lrrk2 knockout has an early neurodevelopmental effect, and leads to perturbed dopamine and serotonin catabolism in a LRRK2 knockout. We propose mzLrrk2 zebrafish as a valuable tool to study LRRK2 loss-of-function in vivo , and provide a link between LRRK2 and the control of basal cell proliferation in the brain that may become potentially critical upon challenges like brain injury.
Publisher: Elsevier BV
Date: 12-2012
DOI: 10.1016/J.DEVCEL.2012.10.014
Abstract: The adult zebrafish brain, unlike mammalian counterparts, can regenerate after injury owing to the neurogenic capacity of stem cells with radial glial character. We hypothesized that injury-induced regenerative programs might be turned on after injury in zebrafish brain and enable regenerative neurogenesis. Here we identify one such gene-the transcription factor gata3-which is expressed only after injury in different zebrafish organs. Gata3 is required for reactive proliferation of radial glia cells, subsequent regenerative neurogenesis, and migration of the newborn neurons. We found that these regeneration-specific roles of Gata3 are dependent on the injury because Gata3 overexpression in the unlesioned adult zebrafish brain is not sufficient to induce neurogenesis. Thus, gata3 acts as a specific injury-induced proregenerative factor that is essential for the regenerative capacity in vertebrates.
Publisher: Public Library of Science (PLoS)
Date: 13-09-2021
DOI: 10.1371/JOURNAL.PGEN.1009794
Abstract: LRRK2 gain-of-function is considered a major cause of Parkinson’s disease (PD) in humans. However, pathogenicity of LRRK2 loss-of-function in animal models is controversial. Here we show that deletion of the entire zebrafish lrrk2 locus elicits a pleomorphic transient brain phenotype in maternal-zygotic mutant embryos (mzLrrk2). In contrast to lrrk2 , the paralog gene lrrk1 is virtually not expressed in the brain of both wild-type and mzLrrk2 fish at different developmental stages. Notably, we found reduced catecholaminergic neurons, the main target of PD, in specific cell populations in the brains of mzLrrk2 larvae, but not adult fish. Strikingly, age-dependent accumulation of monoamine oxidase (MAO)-dependent catabolic signatures within mzLrrk2 brains revealed a previously undescribed interaction between LRRK2 and MAO biological activities. Our results highlight mzLrrk2 zebrafish as a tractable tool to study LRRK2 loss-of-function in vivo , and suggest a link between LRRK2 and MAO, potentially of relevance in the prodromic stages of PD.
Publisher: Wiley
Date: 18-03-2009
DOI: 10.1111/J.1471-4159.2009.05986.X
Abstract: Serotonin (or 5-hydroxytryptamine 5-HT) and monoamine oxidase (MAO) are involved in several physiological functions and pathological conditions. We show that the serotonergic system and its development in zebrafish are similar to those of other vertebrates rendering zebrafish a good model to study them. Development of MAO expression followed a similar time course as the 5-HT system. MAO expression and activity were located in or adjacent to serotonergic nuclei and their targets, especially in the ventral hypothalamus. MAO mRNA was detected in the brain from 24 h post-fertilization and histochemical enzyme activity from 42 h post-fertilization. Deprenyl (100 microM) decreased MAO activity 34-74% depending on the age. Inhibition of MAO by deprenyl strongly increased 5-HT but not dopamine and noradrenaline levels. Deprenyl decreased 5-HT-immunoreactivity in serotonergic neurons and induced novel ectopic 5-HT-immunoreactivity neurons in the diencephalon in a manner dependent on 5-HT uptake. Deprenyl administration decreased locomotion, altered vertical positioning and increased heart rate. Treatment with p-chlorophenylalanine normalized 5-HT levels and rescued the behavioral alteration, indicating that the symptoms were 5-HT dependent. These findings suggest that zebrafish MAO resembles mammalian MAO A more than MAO B, metabolizing mainly 5-HT. Applications of this model of hyperserotonergism include pharmacological and genetic screenings.
Publisher: Elsevier BV
Date: 02-2000
DOI: 10.1016/S0891-0618(99)00052-6
Abstract: Histaminergic neurons in adult vertebrate brain are confined to the posterior hypothalamic area, where they are comprised of scattered groups of neurons referred to as the tuberomammillary nucleus. Histamine regulates hormonal functions, sleep, food intake, thermoregulation and locomotor activity, for ex le. In the zebrafish, Danio rerio, histamine was detected only in the brain, where also the histamine synthesizing enzyme L-histidine decarboxylase (HDC) was expressed. It is possible that histamine has first evolved as a neurotransmitter in the central nervous system. We established sensitive quantitative in situ hybridization methods for histamine H(1) and H(2) receptors and HDC, to study the modulation of brain histaminergic system under pathophysiological conditions. A transient increase in H(1) receptor expression was seen in the dentate gyrus and striatum after a single injection of kainic acid, a glutamate analog. H(1) antagonists are known to increase duration of convulsions, and increased brain histamine is associated with reduced convulsions in animal models of epilepsy. No HDC mRNA was detected in brain vessels by in situ hybridization, which suggests lack of histamine synthesis by brain endothelial cells. This was verified by lack of HDC mRNA in a rat brain endothelial cell line, RBE4 cells. Both H(1) and H(2) receptor mRNA was found in this cell line, and the expression of both receptors was downregulated by dexamethasone. The findings are in agreement with the concept that histamine regulates blood-brain barrier permeability through H(1) and H(2) receptor mediated mechanisms. Hibernation is characterized by a drastic reduction of central functions. The activity of most transmitter systems is maintained at a very low level. Surprisingly, histamine levels and turnover were clearly elevated in hibernating ground squirrels, and the density of histamine-containing fibers was higher than in euthermic animals. It is possible that histamine actively maintains the low activity of other transmitters during the hibernation state.
Publisher: Springer Science and Business Media LLC
Date: 17-11-2018
Publisher: Springer Science and Business Media LLC
Date: 05-2017
DOI: 10.1038/NN.4558
Abstract: Mural cells of the vertebrate brain maintain vascular integrity and function, play roles in stroke and are involved in maintenance of neural stem cells. However, the origins, ersity and roles of mural cells remain to be fully understood. Using transgenic zebrafish, we identified a population of isolated mural lymphatic endothelial cells surrounding meningeal blood vessels. These meningeal mural lymphatic endothelial cells (muLECs) express lymphatic endothelial cell markers and form by sprouting from blood vessels. In larvae, muLECs develop from a lymphatic endothelial loop in the midbrain into a dispersed, nonlumenized mural lineage. muLEC development requires normal signaling through the Vegfc-Vegfd-Ccbe1-Vegfr3 pathway. Mature muLECs produce vascular growth factors and accumulate low-density lipoproteins from the bloodstream. We find that muLECs are essential for normal meningeal vascularization. Together, these data identify an unexpected lymphatic lineage and developmental mechanism necessary for establishing normal meningeal blood vasculature.
Publisher: Wiley
Date: 29-11-2010
DOI: 10.1002/DVDY.22497
Abstract: Cre-mediated site-specific recombination has emerged as an indispensable tool for the precise manipulation of the mammalian genome. Recently, we showed that Cre is also highly efficient in zebrafish and temporal control of recombination can be achieved by using the ligand-inducible CreER(T2). Previous attempts have been made to control recombination by using the temperature inducible hsp70l promoter to conditionally drive the expression of Cre or EGFP-Cre, respectively. However, in this study we demonstrate that the hsp70l promoter possesses a basal leakiness resulting in Cre-mediated recombination even at permissive temperatures. In order to prevent non-conditional recombination, we combined the hsp70l promoter with a mCherry-tagged ligand-inducible CreER(T2). At permissive temperatures and in the absence of the ligand tamoxifen (TAM), no non-conditional recombination is observed indicating tight regulation of CreER(T2). Instead, comprehensive site-specific recombination is mediated following heat induction and administration of TAM.
Publisher: Mary Ann Liebert Inc
Date: 02-2021
Publisher: Wiley
Date: 10-02-2012
DOI: 10.1002/DNEU.20918
Abstract: Adult neurogenesis is a widespread trait of vertebrates however, the degree of this ability and the underlying activity of the adult neural stem cells differ vastly among species. In contrast to mammals that have limited neurogenesis in their adult brains,zebrafish can constitutively produce new neurons along the whole rostrocaudal brain axis throughout its life.This feature of adult zebrafish brain relies on the presence of stem rogenitor cells that continuously proliferate,and the permissive environment of zebrafish brain for neurogenesis. Zebrafish has also an extensive regenerative capacity, which manifests itself in responding to central nervous system injuries by producing new neurons to replenish the lost ones. This ability makes zebrafish a useful model organism for understanding the stem cell activity in the brain, and the molecular programs required for central nervous system regeneration.In this review, we will discuss the current knowledge on the stem cell niches, the characteristics of the stem rogenitor cells, how they are regulated and their involvement in the regeneration response of the adult zebrafish brain. We will also emphasize the open questions that may help guide the future research.
Publisher: AIP Publishing
Date: 09-2017
DOI: 10.1063/1.5001848
Abstract: Dechorionation of zebrafish embryos has been proposed as a tool to improve toxicity bioassays because the chorion membrane forms a molecular barrier that can slow down or prevent chemicals from reaching the embryo. Despite its potential importance for experimental and predictive toxicology, the culture of dechorionated zebrafish embryos in a microfluidic environment has so far not received any attention. Here, we demonstrate a new Lab-on-a-Chip technology capable of automated, hydrodynamic immobilization of dechorionated embryos of Danio rerio. We show that chorion-less embryos can develop normally under microfluidic perfusion and be successfully used for on-chip developmental toxicity bioassays.
Publisher: Wiley
Date: 31-10-2017
Publisher: Elsevier BV
Date: 02-2015
DOI: 10.1016/J.NEUROSCIENCE.2014.12.020
Abstract: Previously, we have demonstrated a role for fibroblast growth factor (Fgf) in spinal cord regeneration in both zebrafish and mouse. We have shown that exogenous Fgf2 treatment attenuates astrocytic gliosis and induces glia cells to become progenitors that undergo neurogenesis as well as differentiating into bipolar astrocytes that support axonal regeneration (Goldshmit et al., 2012, 2014). One of the downstream signaling target genes of Fgf is spry4, which acts as a feedback inhibitor for Fgf signaling. In this study we examined the effects of increased endogenous Fgf signaling, in spry4-/- mice, on the early events that occur after spinal cord injury (SCI). We demonstrate that in spry4-/- mice inflammatory responses, such as tumor necrosis factor α (TNFα) secretion and macrophage/neutrophil invasion into the lesion site are reduced. In addition, astrocytic gliosis is attenuated and neuronal survival is increased. These results further support a pro-regenerative role of Fgf after SCI, and suggest that increased endogenous Fgf signaling after SCI may contribute to functional recovery and therefore presents this pathway as a target for new therapy development.
Publisher: Wiley
Date: 18-06-2004
DOI: 10.1002/CNE.20171
Abstract: Distribution, chemical-neuroanatomy, concentration, and uptake-release properties of histamine (HA)-containing neurons and the possible physiological effects of HA in the central and peripheral nervous system of the pulmonate snails, Helix pomatia and Lymnaea stagnalis, are described. In the CNS of both species, the distribution pattern of HA-immunoreactive (HA-IR) neurons was similar. In both species the majority were located in the buccal, cerebral, and pedal ganglia. In Helix, approximately 400 HA-IR neurons were seen, whereas in Lymnaea approximately 130 labeled cells were visualized. The neuropils, connectives, commissures, several peripheral nerves, and a part of the peripheral tissues (lip and foot of both species and the upper tentacles of Helix) were innervated by HA-IR elements. Numerous sensory cells were found in the tentacles, lip, and statocysts. The HA concentration values assayed by HPLC ranged from 4.8 to 47.4 pmol/mg in the different central ganglia of Helix, and from 4.3 to 18.6 pmol/mg in Lymnaea CNS, whereas the peripheral tissues contained 0.33-1 pmol/mg HA in Helix and 0.26-0.46 pmol/mg in Lymnaea. In the Lymnaea CNS, a high-affinity (37.6 microM), single component 3H-HA uptake system was demonstrated. 3H-HA release evoked by either electrical stimulation or 100 mM K+ could be prevented in Ca2+-free physiological solution. Voltage-cl experiments indicated specific changes caused by HA in the membrane conductance of identified central neurons of Helix and Lymnaea. Exogenously applied 10(-5) M HA resulted in the acceleration of locomotion (gliding by foot cilia) of Lymnaea. The findings suggest an important signaling role of HA, described here for the first time, in the nervous system of higher-order, pulmonate, gastropods, involving efferent, integrative, and sensory functions. The data can also be applied as a background for further specification of HA in the regulation of different behaviors in these species.
Publisher: The Royal Society
Date: 05-02-2007
Abstract: Post-embryonic neurogenesis is a fundamental feature of the vertebrate brain. However, the level of adult neurogenesis decreases significantly with phylogeny. In the first part of this review, a comparative analysis of adult neurogenesis and its putative roles in vertebrates are discussed. Adult neurogenesis in mammals is restricted to two telencephalic constitutively active zones. On the contrary, non-mammalian vertebrates display a considerable amount of adult neurogenesis in many brain regions. The phylogenetic differences in adult neurogenesis are poorly understood. However, a common feature of vertebrates (fish, hibians and reptiles) that display a widespread adult neurogenesis is the substantial post-embryonic brain growth in contrast to birds and mammals. It is probable that the adult neurogenesis in fish, frogs and reptiles is related to the coordinated growth of sensory systems and corresponding sensory brain regions. Likewise, neurons are substantially added to the olfactory bulb in smell-oriented mammals in contrast to more visually oriented primates and songbirds, where much fewer neurons are added to the olfactory bulb. The second part of this review focuses on the differences in brain plasticity and regeneration in vertebrates. Interestingly, several recent studies show that neurogenesis is suppressed in the adult mammalian brain. In mammals, neurogenesis can be induced in the constitutively neurogenic brain regions as well as ectopically in response to injury, disease or experimental manipulations. Furthermore, multipotent progenitor cells can be isolated and differentiated in vitro from several otherwise silent regions of the mammalian brain. This indicates that the potential to recruit or generate neurons in non-neurogenic brain areas is not completely lost in mammals. The level of adult neurogenesis in vertebrates correlates with the capacity to regenerate injury, for ex le fish and hibians exhibit the most widespread adult neurogenesis and also the greatest capacity to regenerate central nervous system injuries. Studying these phenomena in non-mammalian vertebrates may greatly increase our understanding of the mechanisms underlying regeneration and adult neurogenesis. Understanding mechanisms that regulate endogenous proliferation and neurogenic permissiveness in the adult brain is of great significance in therapeutical approaches for brain injury and disease.
Publisher: Society for Neuroscience
Date: 13-05-2009
DOI: 10.1523/JNEUROSCI.0072-09.2009
Abstract: In the adult CNS, neurogenesis takes place in special niches. It is not understood how these niches are formed during development and how they are maintained. In contrast to mammals, stem cell niches are abundant in zebrafish and also found in other parts of the brain than telencephalon. To understand common characteristics of neural stem cell niches in vertebrates, we studied the origin and architecture of a previously unknown stem cell niche using transgenic lines, in vivo imaging, and marker analysis. We show that bipotent stem cells are maintained in a distinct niche in the adult zebrafish cerebellum. Remarkably, the stem cells are not typical glia but instead retain neuroepithelial characteristics. The cerebellar stem cell niche is generated by the coordinated displacement of ventricle and rhombic lip progenitors in a two-step process involving morphogenetic movements and tissue growth. Importantly, the niche and its stem cells still remain in ventricular contact through a previously unknown derivative of the ventricle. Factors propagated in the ventricle are thought to be important regulators of stem cell activity. To test the requirements of one family of important factors, Fibroblast growth factors, we used zebrafish with an inducible dominant-negative Fgf receptor. Inhibition of Fgf signaling leads to significant reduction of stem cell activity. In contrast to the predominant view, adult neural stem cells in nonmammalian vertebrates show more neuroepithelial than glial characteristics. Nevertheless, retained epithelial properties such as distinct polarization and ventricular contact are critical common determinants to maintain neural stem cell activity in vertebrates.
Publisher: Elsevier BV
Date: 02-2002
Publisher: Mary Ann Liebert Inc
Date: 02-2019
Abstract: Zebrafish larvae are suitable in vivo models for toxicological and pharmacological screens due to their transparency, small size, ex utero development, and genetic and physiological similarity to humans. Using modern imaging techniques, cells and tissues can be dynamically visualized over several days in multiple zebrafish larvae. However, precise specimen immobilization and maintenance of homeostatic conditions remain a challenge for longitudinal studies. A highly customizable mounting configuration with inbuilt means of controlling temperature and media flow would therefore be a valuable tool to facilitate long-term imaging of a large number of specimens. Using three-dimensional printing, we have developed a millifluidic, modular homeostatic imaging plate (HIP), which consists of a customizable s le insert and a temperature-controlled incubation chamber that is continuously perfused, providing an ideal environment for long-term experiments where homeostatic conditions are desired. The HIP is cheap to produce, has a standard microtiter well plate format, and can be fitted to most microscopes. We used the device to image dynamic regeneration of spinal cord neurons. The flexibility and adaptability of the HIP facilitate long-term in vivo imaging of many s les, and can be easily adapted to suit a broad range of specimens.
Publisher: Elsevier BV
Date: 11-2018
DOI: 10.1016/J.PNEUROBIO.2018.06.004
Abstract: Neural stem and progenitor cells (NSPCs) are the primary source of new neurons in the brain and serve critical roles in tissue homeostasis and plasticity throughout life. Within the vertebrate brain, NSPCs are located within distinct neurogenic niches differing in their location, cellular composition, and proliferative behaviour. Heterogeneity in the NSPC population is hypothesized to reflect varying capacities for neurogenesis, plasticity and repair between different neurogenic zones. Since the discovery of adult neurogenesis, studies have predominantly focused on the behaviour and biological significance of adult NSPCs (aNSPCs) in rodents. However, compared to rodents, who show lifelong neurogenesis in only two restricted neurogenic niches, zebrafish exhibit constitutive neurogenesis across multiple stem cell niches that provide new neurons to every major brain ision. Accordingly, zebrafish are a powerful model to probe the unique cellular and molecular profiles of NSPCs and investigate how these profiles govern tissue homeostasis and regenerative plasticity within distinct stem cell populations over time. Amongst the NSPC populations residing in the zebrafish central nervous system (CNS), proliferating radial-glia, quiescent radial-glia and neuro-epithelial-like cells comprise the majority. Here, we provide insight into the extent to which these distinct NSPC populations function and mature during development, respond to experience, and contribute to successful CNS regeneration in teleost fish. Together, our review brings to light the dynamic biological roles of these in idual NSPC populations and showcases their erse regenerative modes to achieve vertebrate brain repair later in life.
Publisher: SPIE
Date: 22-12-2015
DOI: 10.1117/12.2202392
Publisher: Wiley
Date: 2001
DOI: 10.1002/CNE.1390
Abstract: The histaminergic system and its relationships to the other aminergic transmitter systems in the brain of the zebrafish were studied by using confocal microscopy and immunohistochemistry on brain whole-mounts and sections. All monoaminergic systems displayed extensive, widespread fiber systems that innervated all major brain areas, often in a complementary manner. The ventrocaudal hypothalamus contained all monoamine neurons except noradrenaline cells. Histamine (HA), tyrosine hydroxylase (TH), and serotonin (5-HT) -containing neurons were all found around the posterior recess (PR) of the caudal hypothalamus. TH- and 5-HT-containing neurons were found in the periventricular cell layer of PR, whereas the HA-containing neurons were in the surrounding cell layer as a distinct boundary. Histaminergic neurons, which send widespread ascending and descending fibers, were all confined to the ventrocaudal hypothalamus. Histaminergic neurons were medium in size (approximately 12 microm) with varicose ascending and descending ipsilateral and contralateral fiber projections. Histamine was stored in vesicles in two types of neurons and fibers. A close relationship between HA fibers and serotonergic raphe neurons and noradrenergic locus coeruleus neurons was evident. Putative synaptic contacts were occasionally detected between HA and TH or 5-HT neurons. These results indicate that reciprocal contacts between monoaminergic systems are abundant and complex. The results also provide evidence of homologies to mammalian systems and allow identification of several previously uncharacterized systems in zebrafish mutants.
Publisher: Elsevier BV
Date: 08-2009
Publisher: SPIE
Date: 22-12-2015
DOI: 10.1117/12.2202390
Publisher: Public Library of Science (PLoS)
Date: 27-02-2009
Publisher: Springer Science and Business Media LLC
Date: 02-07-2005
DOI: 10.1007/S00441-005-1134-4
Abstract: The distribution and chemical neuroanatomy of nervous elements and certain pharmacological-physiological characteristics of the innervation of the body wall in earthworms are described. Solitary sensory bipolar cells can be found among the epithelial cells. These bipolar cells contain serotonin, tyrosine hydroxylase, histamine, gamma-amino-butyric acid (GABA), Eisenia tetradecapeptide, proctolin or rhodopsin in various combinations. In the body wall, the plexus sub-muscularis is composed of nerve fibres only, whereas the plexus sub-epithelialis and muscularis also contain solitary nerve cells. These cells display histamine, GABA or neuropeptide Y immunoreactivity. The fibres of the three plexuses are reactive to serotonin, histamine, Eisenia tetradecapeptide, proctolin, GABA and neuropeptide Y antibodies. FMRFamide-immunoreactive fibres of the plexus muscularis originate from the central nervous system, whereas axons containing the other studied molecules are derived from both peripheral and central structures. High pressure liquid chromatography assays have revealed serotonin, dopamine and histamine in the body wall. Contractions of the body wall musculature can be elicited with serotonin and FMRFamide. Serotonin-evoked contractions are suppressed by the application of GABA. Serotonin acts both directly on the muscle cell receptors and indirectly through initiating transmitter release from the nervous elements, whereas the FMRFamide-induced contractions seem to be mediated through the muscle cell receptors only. The pharmacological profiles of the serotonin and GABA receptors resemble those of the vertebrate 5-HT(3) and GABA(B) receptor types. Our findings indicate that both the sensory and efferent system of the annelid body wall operate by means of a variety of neuroactive compounds, suggesting a complex role of signalling systems in the regulation of this organ.
Publisher: The Company of Biologists
Date: 2017
DOI: 10.1242/DEV.144907
Abstract: Zebrafish can regenerate brain injury, and the regenerative process is driven by resident stem cells. Stem cells are heterogeneous in the vertebrate brain, but the significance of having heterogeneous stem cells in regeneration is not understood. Limited availability of specific stem cells might impair the regeneration of particular cell lineages. We studied regeneration ability of the adult zebrafish cerebellum. The zebrafish cerebellum contains two major stem and progenitor cell types, ventricular zone and neuroepithelial cells. Using conditional lineage tracing, we demonstrate that cerebellar regeneration depends on availability of specific stem cells. Radial glia-like cells are thought to be the predominating stem cell type in homeostasis and after injury. However, we find that radial glia-like cells play a minor part in adult cerebellar neurogenesis and in recovery after injury. Instead, we find that neuroepithelial cells are the predominant stem cell type supporting cerebellar regeneration after injury. Zebrafish are able to regenerate many, but not all cell types in the cerebellum, which emphasizes the need to understand the contribution of different adult neural stem and progenitor cell subtypes in the vertebrate CNS.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Cold Spring Harbor Laboratory
Date: 04-02-2019
DOI: 10.1101/539940
Abstract: Zebrafish have a remarkable capacity to regenerate following spinal cord (SC) injury but the responsible cellular events are not well understood. We used in vivo imaging and genetics to pin-point specific cellular processes controlling SC regeneration in zebrafish. We identified two temporally and mechanistically distinct phases of cellular regeneration in the SC. The initial phase relies on migration of precursor neurons to the injury, enabling rapid functional recovery, and activation of quiescent neural progenitor cells (NPCs). A second phase of regenerative neurogenesis compensates for both the lost tissue and cells depleted due to precursor neuron migration. We propose a critical role of precursor neurons recruitment in initiating neuronal circuit recovery and buying sufficient time for regenerative neurogenesis to take place. Taken together, our data suggests an unanticipated role of precursor cell recruitment in driving neural repair and functional recovery during the regenerative response.
Publisher: Springer Science and Business Media LLC
Date: 24-11-2016
DOI: 10.1038/SREP37678
Abstract: Lysophosphatidic acid (LPA) is a unique bioactive lysophospholipid that induces pleiotropic effects in various cell types and organisms by acting on its specific receptors. LPA is mainly synthetised extracellularly by the ectonucleotide pyrophosphatase hosphodiesterase 2/autotaxin (enpp2). Altered LPA signalling is associated with embryonic abnormalities, suggesting critical roles for LPA during development. However, the role of LPA signalling during early embryogenesis is not well established. We demonstrate that enpp2/LPA signalling in the early zebrafish embryo results in altered axis and midline formation, defects in left right (L-R) patterning, ciliogenesis of the Kupffer’s vesicle (KV), through the modulation of cell migration during gastrulation in a lpar 1–3 Rho/ROCK-dependant manner. Overall, this study demonstrates an essential role of enpp2/LPA signalling during early embryogenesis.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Public Library of Science (PLoS)
Date: 09-09-2013
Publisher: Wiley
Date: 07-1996
Publisher: The Endocrine Society
Date: 04-2005
DOI: 10.1210/EN.2004-1452
Abstract: To survive winter the Siberian hamster has evolved profound physiological and behavioral adaptations, including a moult to winter pelage, regression of the reproductive axis, onset of daily torpor and increased capacity for thermogenesis. However, one of the most striking adaptations is the catabolism of intraabdominal and sc fat reserves contributing to the loss of up to 40% of body weight. These physiological and behavioral adaptations are photoperiodically driven, yet neither the site(s) in the brain nor the molecular mechanism(s) involved in the regulation of these profound adaptations is known. Here we report a dynamic regulation of gene expression in a dorsal region of the medial posterior area of the arcuate nucleus (dmpARC) of the Siberian and Syrian hamster brain in response to altered photoperiod. We show mRNA for the histamine H3 receptor is down-regulated and VGF is up-regulated in the dmpARC in hamsters switched from long- to short-day photoperiod. These data provide further evidence to support the view that the dmpARC is a major site to relay photoperiodic changes and as a site for the long-term regulation of seasonal physiology and behavior.
Publisher: Elsevier BV
Date: 08-2021
Publisher: Wiley
Date: 12-1998
DOI: 10.1046/J.1460-9568.1998.00394.X
Abstract: The histamine-storing neural system in adult and developing zebrafish (Danio rerio) was studied with immunocytochemical and chromatographical methods. Furthermore, the gene for histidine decarboxylase was partially cloned and its expression mapped with in situ hybridization. The histamine-storing neurons were only seen in the caudal hypothalamus, around the posterior recess of the diencephalic ventricle. Almost all parts of the brain, except the cerebellum, contained at least some histamine-immunoreactive fibres. The ascending projections had the rostral part of the dorsal telencephalon as a major target. Descending projections terminated in the torus semicircularis, central grey and inferior olive. A prominent innervation of the optic tectum, which has not been reported in other fish, was seen. The in situ hybridization gave a strong signal in cells with the same anatomical position as the histamine-immunoreactive neurons. The first histamine-immunoreactive neurons appeared in the ventral hypothalamus at about 85 h post-fertilization, and at 90 h, immunoreactive fibres terminated in the dorsal telencephalon. The embryonic histamine production described in mammals was lacking in this species. Both immunocytochemical and chromatographical studies indicated that histamine is absent in all other parts of the zebrafish body, and no specific hybridization was seen in any other part of the fish than the hypothalamus. The zebrafish could therefore be a very useful model for pharmacological in vivo studies of the histaminergic system of the brain, since the powerful peripheral actions of histamine should be lacking in this species.
Publisher: Wiley
Date: 13-01-2014
DOI: 10.1002/BRB3.172
Publisher: Springer Science and Business Media LLC
Date: 13-01-2021
DOI: 10.1038/S41598-020-79637-9
Abstract: Identifying endogenous tissue stem cells remains a key challenge in developmental and regenerative biology. To distinguish and molecularly characterise stem cell populations in large heterogeneous tissues, the combination of cytochemical cell markers with ultrastructural morphology is highly beneficial. Here, we realise this through workflows of multi-resolution immuno -correlative light and electron microscopy ( i CLEM) methodologies. Taking advantage of the antigenicity preservation of the Tokuyasu technique, we have established robust protocols and workflows and provide a side-by-side comparison of i CLEM used in combination with scanning EM (SEM), scanning TEM (STEM), or transmission EM (TEM). Evaluation of the applications and advantages of each method highlights their practicality for the identification, quantification, and characterization of heterogeneous cell populations in small organisms, organs, or tissues in healthy and diseased states. The i CLEM techniques are broadly applicable and can use either genetically encoded or cytochemical markers on plant, animal and human tissues. We demonstrate how these protocols are particularly suited for investigating neural stem and progenitor cell populations of the vertebrate nervous system.
Publisher: Elsevier BV
Date: 04-2007
DOI: 10.1016/J.BCP.2007.01.014
Abstract: Neuronal histamine regulates several functions in the vertebrate brain. The zebrafish brain contains a widespread histaminergic system and H(3) receptor ligand binding has been reported. In this study we provide evidence for the existence of histamine H(1), H(2) and H(3) receptor genes in zebrafish. Single copies of putative histamine H(1), H(2) and H(3) receptors were identified and cloned from the zebrafish brain. Expression analysis suggested that they are expressed in the brain and a few other tissues. Widespread distribution of zebrafish H(2) receptor binding sites was detected with [(125)I]iodoaminopotentidine in brain sections. Zebrafish larvae were exposed to 1, 10 or 100 microM of the H(1) ligand pyrilamine, the H(2) ligand cimetidine and the H(3) ligands thioperamide and immepip for 5 days. Significant decreases in swimming distance were observed with the highest dose of all ligands, whereas cimetidine gave a significant decrease also with 1 and 10 microM doses. These results provide the first molecular biological evidence for the presence of histamine receptors in zebrafish. These histamine receptors resemble those of higher vertebrates and they provide a useful model for pharmacological and behavioral studies for characterizing the functions of histamine in more detail.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 07-12-2012
Abstract: The zebrafish brain is much more adept than the human brain at recovering after traumatic injury. Kyritsis et al. (p. 1353 , published online 8 November see the Perspective by Stella ) investigated the cellular events that support regeneration in the zebrafish brain. Although inflammation is part of the response in both settings, the zebrafish brain goes on to initiate proliferation of replacement neurons. By inciting inflammation without neuronal damage, radial glial cells could be pushed into neurogenesis.
Publisher: Wiley
Date: 22-12-2003
DOI: 10.1111/J.1471-4159.2004.02190.X
Abstract: Dopaminergic deficiency in the brain of zebrafish was produced by systemic administration of two catecholaminergic neurotoxins, 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and the neurochemical and behavioural changes were characterized. The levels of dopamine and noradrenaline decreased significantly after the injection of MPTP and 6-OHDA. Corresponding to these changes, fish exhibited characteristic changes in locomotor behaviour, i.e. the total distance moved and velocity decreased after both neurotoxins. Tyrosine hydroxylase and caspase 3 protein levels were not altered after MPTP or 6-OHDA injections, as studied by immunohistochemistry and western blotting. The catecholaminergic cell clusters suggested to correspond to the mammalian nigrostriatal cell group displayed normal tyrosine hydroxylase immunoreactivity after the toxin treatment and did not show signs of DNA fragmentation that would indicate activation of cascades that lead to cell death. The results show that single systemic injections of MPTP and 6-OHDA induce both biochemical and behavioural changes in zebrafish, albeit failing to produce any significant morphological alteration in catecholaminergic cell clusters at the tested doses. This approach may be used for the screening of chemicals affecting the dopaminergic system. The model may be especially useful for evaluation of the role of novel genes in neurotoxicity, as a large number of zebrafish mutants are becoming available.
Publisher: Springer Netherlands
Date: 2019
Publisher: Cold Spring Harbor Laboratory
Date: 19-02-2018
DOI: 10.1101/268136
Abstract: How erse adult stem and progenitor populations regenerate tissue following damage to the CNS remains unknown across most neurogenic domains. To understand the role of quiescent radial-glial (qRG) stem cells during regeneration, we tested the hypothesis that qRG could be induced to proliferate and produce newborn neurons. We designed a stab lesion assay in the midbrain tectum of the adult zebrafish to target an isolated population of qRG, and investigated their proliferative behaviour, differentiation potential, and requirement of Wnt/β-catenin signalling for the regenerative response. EdU-labelling showed that a small proportion of qRG transit to a proliferative state (pRG), but that progeny of pRG are restricted to a radial-glial fate. Lesion promoted upregulation of proliferation and neurogenesis from neuro-epithelial-like lifying progenitors (NE-Ap) of the tectal marginal zone (TMZ). Homeostatic levels of Wnt/β-catenin signalling persisted under lesioned conditions in the qRG RG population, whereby increased β-catenin staining and axin2 expression was present in the NE-Ap progenitor zone. Attenuation of Wnt signalling using Dickkopf-1 , demonstrated that proliferative responses post-injury appeared to be Wnt-independent. Our results align with the emerging view that adult stem rogenitor phenotypes are characterized by discrete, rather than mutual, regenerative programs and that different stem cell domains employ different modes of regeneration.
Publisher: Wiley
Date: 20-05-2010
DOI: 10.1002/GLIA.21012
Abstract: Adult telencephalic neurogenesis is a conserved trait of all vertebrates studied. It has been investigated in detail in rodents, but very little is known about the composition of neurogenic niches and the cellular nature of progenitors in nonmammalian vertebrates. To understand the components of the progenitor zones in the adult zebrafish telencephalon and the link between glial characteristics and progenitor state, we examined whether canonical glial markers are colocalized with proliferation markers. In the adult zebrafish telencephalon, we identify heterogeneous progenitors that reside in two distinct glial domains. We find that the glial composition of the progenitor zone is linked to its proliferative behavior. Analyzing both fast-cycling proliferating cells as well as slowly cycling progenitors, we find four distinct progenitor types characterized by differential expression of glial markers. Importantly, a significant proportion of progenitors do not display typical radial glia characteristics. By blocking or activating Fgf signaling by misexpression of a dominant negative Fgf-receptor 1 or Fgf8a, respectively, we find that ventral and dorsal progenitors in the telencephalon also differ in their requirement for Fgf signaling. Together with data on the expression of Fgf signaling components in the ventricular zone of the telencephalon, this suggests that Fgf signaling directly regulates proliferation of specific subsets of adult telencephalic progenitors in vivo. Taken together our results show that adult neural progenitor cells are heterogeneous with their respect to distribution into two distinct glial domains and their dependence upon Fgf signaling as a proliferative cue in the zebrafish telencephalon.
Publisher: Wiley
Date: 08-08-2005
DOI: 10.1111/J.1471-4159.2005.03305.X
Abstract: The alpha2-adrenoceptors are G-protein-coupled receptors that mediate many of the physiological effects of norepinephrine and epinephrine. Mammals have three subtypes of alpha2-adrenoceptors, alpha2A, alpha2B and alpha2C. Zebrafish, a teleost fish used widely as a model organism, has five distinct alpha2-adrenoceptor genes. The zebrafish has emerged as a powerful tool to study development and genetics, with many mutations causing diseases reminiscent of human diseases. Three of the zebrafish adra2 genes code for orthologues of the mammalian alpha2-adrenoceptors, while two genes code for alpha2Da- and alpha2Db- adrenoceptors, representing a duplicated, fourth alpha2-adrenoceptor subtype. The three different mammalian alpha2-adrenoceptor subtypes have distinct expression patterns in different organs and tissues, and mediate different physiological functions. The zebrafish alpha2-adrenergic system, with five different alpha2-adrenoceptors, appears more complicated. In order to deduce the physiological functions of the zebrafish alpha2-adrenoceptors, we localized the expression of the five different alpha2-adrenoceptor subtypes using RT-PCR, mRNA in situ hybridization, and receptor autoradiography using the radiolabelled alpha2-adrenoceptor antagonist [ethyl-3H]RS-79948-197. Localization of the alpha2A-, alpha2B- and alpha2C-adrenoceptors in zebrafish shows marked conservation when compared with mammals. The zebrafish alpha2A, alpha2Da, and alpha2Db each partially follow the distribution pattern of the mammalian alpha2A: a possible indication of subfunction partitioning between these subtypes. The alpha2-adrenergic system is functional in zebrafish also in vivo, as demonstrated by marked locomotor inhibition, similarly to mammals, and lightening of skin colour induced by the specific alpha2-adrenoceptor agonist, dexmedetomidine. Both effects were antagonized by the specific alpha2-adrenoceptor antagonist atipamezole.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 19-07-2013
Publisher: Mary Ann Liebert Inc
Date: 12-2017
Abstract: How distinct cell populations are distributed in three-dimensional space under homeostasis or following injury, neurodegeneration, or with senescence can teach us much about brain-wide patterns and signaling along the neuroaxis. Visualizing in idual cell populations in the mature vertebrate central nervous system (CNS) has remained a challenge as a result of difficulty clearing adult brain tissue or limitations in imaging depth or resolution. We have developed a simple clearing and imaging pipeline optimally suited for the adult zebrafish brain to investigate changes in patterns of cell proliferation in wild-type and transgenic backgrounds that can easily be quantified and represented using FIJI and IMARIS software.
Publisher: Springer Science and Business Media LLC
Date: 14-03-2019
DOI: 10.1038/S41598-019-40734-Z
Abstract: How erse adult stem and progenitor populations regenerate tissue following damage to the brain is poorly understood. In highly regenerative vertebrates, such as zebrafish, radial-glia (RG) and neuro-epithelial-like (NE) stem rogenitor cells contribute to neuronal repair after injury. However, not all RG act as neural stem rogenitor cells during homeostasis in the zebrafish brain, questioning the role of quiescent RG (qRG) post-injury. To understand the function of qRG during regeneration, we performed a stab lesion in the adult midbrain tectum to target a population of homeostatic qRG, and investigated their proliferative behaviour, differentiation potential, and Wnt/β-catenin signalling. EdU-labelling showed a small number of proliferating qRG after injury (pRG) but that progeny are restricted to RG. However, injury promoted proliferation of NE progenitors in the internal tectal marginal zone (TMZi) resulting in lified regenerative neurogenesis. Increased Wnt/β-catenin signalling was detected in TMZi after injury whereas homeostatic levels of Wnt/β-catenin signalling persisted in qRG RG. Attenuation of Wnt signalling suggested that the proliferative response post-injury was Wnt/β-catenin-independent. Our results demonstrate that qRG in the tectum have restricted capability in neuronal repair, highlighting that RG have erse functions in the zebrafish brain. Furthermore, these findings suggest that endogenous stem cell compartments compensate lost tissue by lifying homeostatic growth.
Publisher: Cold Spring Harbor Laboratory
Date: 04-10-2022
DOI: 10.1101/2022.10.03.510585
Abstract: Mucopolysaccharidoses are lysosomal storage diseases that collectively represent a major cause of lethal, treatment-refractory childhood dementias 1–7 Clinically-useful interventions are h ered due to an incomplete understanding of their neuropathological origins. Using the zebrafish sgsh model of mucopolysaccharidosis IIIA 8 (MPS IIIA, Sanfilippo syndrome A), we conducted several ‘omics-based analyses, and developed and benchmarked a novel bioinformatic feature classification and ranking model for high-throughput datasets – ExIR – to prioritise important features in the progression of neurological manifestations of the disease. We find that the massive endolysosomal burden resulting from increased lysosomal storage of heparan sulfate and other secondarily accumulating substrates, such as sphingolipids, induces abnormal microtubule organisation and vesicle trafficking in neurons. This results in a gradual impairment of synaptic vesicle localisation at the presynaptic terminal and consequently impaired neuronal activity. Importantly, the endolysosomal phenotype in MPS IIIA zebrafish well-precedes the onset of neural pathology, though the larval MPS IIIA brain was found to be more susceptible to perturbation than wild type siblings. Collectively, these analyses demonstrate the presence of a progressive ‘functional neurodegenerative’ phenotype underpinning neurological disease in MPS IIIA. Our findings provide direct mechanistic evidence linking the well-described lysosomal storage basis for MPS IIIA to its disproportionately severe neural clinical involvement, enabling development and refinement of future therapeutic interventions for this currently untreatable disorder. MPS IIIA represents one of the most common causes of broadly fatal childhood dementia, but the mechanisms underlying disease progression are poorly understood. The first systems-level analyses of disease state and progression in the CNS of an MPS IIIA animal model were performed. Ex perimental data-based I ntegrative R anking (ExIR) was developed to provide unbiased prioritisation and classification of biological data as drivers, biomarkers and mediators of biological processes from high-throughput data at a systems level. Application of ExIR to a transcriptomic and proteomic analyses of a zebrafish model of MPS IIIA implies progressive deficiencies in synaptic activity as a key driver of disease progression correlating with progressive neuronal endolysosomal burden and secondary storage diseases. A novel unifying explanation of pathobiology and progression of MPS IIIA facilitates identification of clinically targetable features and may be generalised to other neuronopathic storage disorders.
Publisher: Elsevier BV
Date: 10-2011
Publisher: Elsevier BV
Date: 08-2019
DOI: 10.1016/J.AQUATOX.2019.105227
Abstract: The environmental impact of exposure to 3D-printed plastics as well as potential migration of toxic chemicals from 3D-printed plastics remains largely unexplored. In this work we applied leachates from plastics fabricated using a stereolithography (SLA) process to early developmental stages of zebrafish (Danio rerio) to investigate developmental toxicity and neurotoxicity. Migration of unpolymerized photoinitiator, 1-hydroxycyclohexyl phenyl ketone (1-HCHPK) from a plastic solid phase to aqueous media at up to 200 mg/L in the first 24 h was detected using gas chromatography-mass spectrometry. Both plastic extracts (LC
Publisher: F1000 Research Ltd
Date: 17-12-2014
DOI: 10.12688/F1000RESEARCH.5595.1
Abstract: Background : The telencephalon shows a remarkable structural ersity among vertebrates. In particular, the everted telencephalon of ray-finned fishes has a markedly different morphology compared to the evaginated telencephalon of all other vertebrates. This difference in development has h ered the comparison between different areas of the pallium of ray-finned fishes and the pallial nuclei of all other vertebrates. Various models of homology between pallial sub isions in ray-finned fishes and the pallial nuclei in tetrapods have been proposed based on connectional, neurochemical, gene expression and functional data. However, no consensus has been reached so far. In recent years, the analysis of conserved developmental marker genes has assisted the identification of homologies for different parts of the telencephalon among several tetrapod species. Results : We have investigated the gene expression pattern of conserved marker genes in the adult zebrafish ( Danio rerio) pallium to identify pallial sub isions and their homology to pallial nuclei in tetrapods. Combinatorial expression analysis of ascl1a , eomesa , emx1 , emx2 , emx3 , and Prox1 identifies four main isions in the adult zebrafish pallium. Within these sub isions, we propose that Dm is homologous to the pallial amygdala in tetrapods and that the dorsal sub ision of Dl is homologous to part of the hippoc al formation in mouse. We have complemented this analysis be examining the gene expression of emx1 , emx2 and emx3 in the zebrafish larval brain. Conclusions : Based on our gene expression data, we propose a new model of sub isions in the adult zebrafish pallium and their putative homologies to pallial nuclei in tetrapods. Pallial nuclei control sensory, motor, and cognitive functions, like memory, learning and emotion. The identification of pallial sub isions in the adult zebrafish and their homologies to pallial nuclei in tetrapods will contribute to the use of the zebrafish system as a model for neurobiological research and human neurodegenerative diseases.
Publisher: Springer Science and Business Media LLC
Date: 2013
Publisher: MDPI AG
Date: 29-08-2022
DOI: 10.3390/MD20090554
Abstract: Many targeted natural product isolation approaches rely on the use of pre-existing bioactivity information to inform the strategy used for the isolation of new bioactive compounds. Bioactivity information can be available either in the form of prior assay data or via Structure Activity Relationship (SAR) information which can indicate a potential chemotype that exhibits a desired bioactivity. The work described herein utilizes a unique method of targeted isolation using structure-based virtual screening to identify potential antibacterial compounds active against MRSA within the marine sponge order Verongiida. This is coupled with molecular networking-guided, targeted isolation to provide a novel drug discovery procedure. A total of 12 previously reported bromotyrosine-derived alkaloids were isolated from the marine sponge species Pseudoceratina durissima, and the compound, (+)-aeroplysinin-1 (1) displayed activity against the MRSA pathogen (MIC: µg/mL). The compounds (1–3, 6 and 9) were assessed for their central nervous system (CNS) interaction and behavioral toxicity to zebrafish (Danio rerio) larvae, whereby several of the compounds were shown to induce significant hyperactivity. Anthelmintic activity against the parasitic nematode Haemonchus contorutus was also evaluated (2–4, 6–8).
Publisher: Springer International Publishing
Date: 2016
Publisher: F1000 Research Ltd
Date: 04-11-2015
DOI: 10.12688/F1000RESEARCH.5595.2
Abstract: Background : The telencephalon shows a remarkable structural ersity among vertebrates. In particular, the everted telencephalon of ray-finned fishes has a markedly different morphology compared to the evaginated telencephalon of all other vertebrates. This difference in development has h ered the comparison between different areas of the pallium of ray-finned fishes and the pallial nuclei of all other vertebrates. Various models of homology between pallial sub isions in ray-finned fishes and the pallial nuclei in tetrapods have been proposed based on connectional, neurochemical, gene expression and functional data. However, no consensus has been reached so far. In recent years, the analysis of conserved developmental marker genes has assisted the identification of homologies for different parts of the telencephalon among several tetrapod species. Results : We have investigated the gene expression pattern of conserved marker genes in the adult zebrafish ( Danio rerio) pallium to identify pallial sub isions and their homology to pallial nuclei in tetrapods. Combinatorial expression analysis of ascl1a , eomesa , emx1 , emx2 , emx3 , and Prox1 identifies four main isions in the adult zebrafish pallium. Within these sub isions, we propose that Dm is homologous to the pallial amygdala in tetrapods and that the dorsal sub ision of Dl is homologous to part of the hippoc al formation in mouse. We have complemented this analysis be examining the gene expression of emx1 , emx2 and emx3 in the zebrafish larval brain. Conclusions : Based on our gene expression data, we propose a new model of sub isions in the adult zebrafish pallium and their putative homologies to pallial nuclei in tetrapods. Pallial nuclei control sensory, motor, and cognitive functions, like memory, learning and emotion. The identification of pallial sub isions in the adult zebrafish and their homologies to pallial nuclei in tetrapods will contribute to the use of the zebrafish system as a model for neurobiological research and human neurodegenerative diseases.
Publisher: The Company of Biologists
Date: 2020
DOI: 10.1242/DEV.176750
Abstract: The vertebrate inner ear employs sensory hair cells and neurons to mediate hearing and balance. In mammals, damaged hair cells and neurons are not regenerated. In contrast, hair cells in the inner ear of zebrafish are produced throughout life and regenerate after trauma. However, it is unknown whether new sensory neurons are also formed in the adult zebrafish statoacoustic ganglion (SAG), the sensory ganglion connecting the inner ear to the brain. Using transgenic lines and marker analysis, we identify distinct cell populations and anatomical landmarks in the juvenile and adult SAG. In particular, we analyze a Neurod/Nestin-positive progenitor pool that produces large amounts of new neurons at juvenile stages, which transitions to a quiescent state in the adult SAG. Moreover, BrdU pulse chase experiments reveal the existence of a proliferative but otherwise marker-negative cell population that replenishes the Neurod/Nestin-positive progenitor pool at adult stages. Taken together, our study represents the first comprehensive characterization of the adult zebrafish SAG showing that zebrafish, in sharp contrast to mammals, display continued neurogenesis in the SAG well beyond embryonic and larval stages.
Publisher: Mary Ann Liebert Inc
Date: 02-2019
Abstract: Gene editing using clustered regularly interspaced short palindromic repeats (CRISPR) is widely used throughout the zebrafish community for the generation of knockouts and knockins. One of the bottlenecks that exists during the process is the laborious screening of injected embryos for F0 founder fish or CRISPants, weeks after the injection date. In this study we show that the use of fluorescently tagged tracrRNA and sorting for fluorescent embryos as early as the 512-cell stage using stereomicroscope significantly improve yield of fish with successfully CRISPR/Cas9-edited genomes. This is a cost-effective strategy that significantly improves workflow and efficacy in genome editing in particular for less experienced researchers.
Publisher: MDPI AG
Date: 31-05-2021
DOI: 10.3390/IJMS22115948
Abstract: Mucopolysaccharidosis IIIA (MPS IIIA, Sanfilippo syndrome type A), a paediatric neurological lysosomal storage disease, is caused by impaired function of the enzyme N-sulfoglucosamine sulfohydrolase (SGSH) resulting in impaired catabolism of heparan sulfate glycosaminoglycan (HS GAG) and its accumulation in tissues. MPS IIIA represents a significant proportion of childhood dementias. This condition generally leads to patient death in the teenage years, yet no effective therapy exists for MPS IIIA and a complete understanding of the mechanisms of MPS IIIA pathogenesis is lacking. Here, we employ targeted CRISPR/Cas9 mutagenesis to generate a model of MPS IIIA in the zebrafish, a model organism with strong genetic tractability and amenity for high-throughput screening. The sgshΔex5−6 zebrafish mutant exhibits a complete absence of Sgsh enzymatic activity, leading to progressive accumulation of HS degradation products with age. sgshΔex5−6 zebrafish faithfully recapitulate erse CNS-specific features of MPS IIIA, including neuronal lysosomal overabundance, complex behavioural phenotypes, and profound, lifelong neuroinflammation. We further demonstrate that neuroinflammation in sgshΔex5−6 zebrafish is largely dependent on interleukin-1β and can be attenuated via the pharmacological inhibition of Caspase-1, which partially rescues behavioural abnormalities in sgshΔex5−6 mutant larvae in a context-dependent manner. We expect the sgshΔex5−6 zebrafish mutant to be a valuable resource in gaining a better understanding of MPS IIIA pathobiology towards the development of timely and effective therapeutic interventions.
Publisher: American Chemical Society (ACS)
Date: 10-11-2015
Abstract: The fish embryo toxicity (FET) biotest has gained popularity as one of the alternative approaches to acute fish toxicity tests in chemical hazard and risk assessment. Despite the importance and common acceptance of FET, it is still performed in multiwell plates and requires laborious and time-consuming manual manipulation of specimens and solutions. This work describes the design and validation of a microfluidic Lab-on-a-Chip technology for automation of the zebrafish embryo toxicity test common in aquatic ecotoxicology. The innovative device supports rapid loading and immobilization of large numbers of zebrafish embryos suspended in a continuous microfluidic perfusion as a means of toxicant delivery. Furthermore, we also present development of a customized mechatronic automation interface that includes a high-resolution USB microscope, LED cold light illumination, and miniaturized 3D printed pumping manifolds that were integrated to enable time-resolved in situ analysis of developing fish embryos. To investigate the applicability of the microfluidic FET (μFET) in toxicity testing, copper sulfate, phenol, ethanol, caffeine, nicotine, and dimethyl sulfoxide were tested as model chemical stressors. Results obtained on a chip-based system were compared with static protocols performed in microtiter plates. This work provides evidence that FET analysis performed under microperfusion opens a brand new alternative for inexpensive automation in aquatic ecotoxicology.
Publisher: Wiley
Date: 21-05-2002
DOI: 10.1046/J.1471-4159.2002.00871.X
Abstract: We investigated histamine concentration in post-mortem brain s les of patients with Parkinson's disease (PD, n = 24), multiple system atrophy (MSA, n = 8) and age-matched controls (n = 27). Histamine concentrations were significantly increased in the putamen (to 159% of the control mean), substantia nigra pars compacta (to 201%), internal globus pallidus (to 234%) and external globus pallidus (to 200%), i.e. in areas which play a crucial role in the motor behaviour and which show typical functional alterations in PD. In MSA no significant differences were seen. Tele-methylhistamine (histamine metabolite) concentrations were unchanged in PD. These results indicate that histamine concentration, but not its metabolism is increased in PD, but not in MSA. This finding may have implications in developing new drug therapies for PD and in differential diagnosis between PD and MSA.
Publisher: American Chemical Society (ACS)
Date: 28-08-2019
Publisher: Elsevier BV
Date: 02-2018
DOI: 10.1016/J.SCITOTENV.2017.09.260
Abstract: Dimethyl sulfoxide (DMSO) is a universally used aprotic solvent with the ability to permeate biological membranes and thus is commonly used to achieve appropriate biological availability of hydrophobic toxicants. While DMSO as a carrier medium has a reportedly low toxicity and is routinely employed in ecotoxicology, very little is known about its effect on dynamic behavioral parameters. This study presents a comparative analysis of the lethal and behavioral effects of exposures to DMSO concentrations of 0.1-10% on several test species such as: neonates of the freshwater crustacean Daphnia magna, nauplii of the marine crustacean Artemia franciscana, the marine crustacean Allorchestes compressa, embryos and larvae of the freshwater fish Danio rerio. The results demonstrated that DMSO did not cause statistically significant mortality even at concentrations close to 1% but induced clear and significant behavioral abnormalities in response to sublethal concentrations on all test species. These included hypoactivity syndrome in A. franciscana, A. compressa, D. magna and zebrafish larvae while a slight time-dependent hyperactivity response was observed in zebrafish embryos. For the majority of test species, behavioral changes such as moving distance, acceleration and burst movement were often observed during the first hours of exposure. These results indicate that caution should be exercised when using DMSO as a carrier solvent in experiments assessing behavioral endpoints.
Location: Germany
Start Date: 2021
End Date: 12-2023
Amount: $343,081.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2021
End Date: 04-2024
Amount: $664,800.00
Funder: Australian Research Council
View Funded Activity