ORCID Profile
0000-0003-1152-0653
Current Organisation
University of Oxford
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Publisher: Society for Neuroscience
Date: 18-08-2004
DOI: 10.1523/JNEUROSCI.1979-04.2004
Abstract: Fast inhibition in the nervous system is commonly mediated by GABA A receptors comprised of 2α/2β/1γ subunits. In contrast, GABA C receptors containing onlyρ subunits (ρ1-ρ3) have been predominantly detected in the retina. However, here using reverse transcription-PCR and in situ hybridization we show that mRNA encoding the ρ1 subunit is highly expressed in brainstem neurons. Immunohistochemistry localized the ρ1 subunit to neurons at light and electron microscopic levels, where it was detected at synaptic junctions. Application of the GABA C receptor agonist cis- 4-aminocrotonic acid (100-800 μM) requires the ρ1 subunit to elicit responses, which surprisingly are blocked independently by antagonists to GABA A (bicuculline, 10 μM) and GABA C [(1,2,5,6-tetrahydropyridin-4-yl)methylphosphinic acid (TPMPA) 40-160 μM] receptors. Responses to GABA C agonists were also enhanced by the GABA A receptor modulator pentobarbitone (300 μM). Spontaneous and evoked IPSPs were reduced in litude but never abolished by TPMPA, but were completely blocked by bicuculline. We therefore tested the hypothesis that GABA A and GABA C subunits formed a heteromeric receptor. Immunohistochemistry indicated that ρ1 and α1 subunits were colocalized at light and electron microscopic levels. Electrophysiology revealed that responses to GABA C receptor agonists were enhanced by the GABA A receptor modulator zolpidem (500 n m ), which acts on the α1 subunit when the γ2 subunit is also present. Finally, coimmunoprecipitation indicated that the ρ1 subunit formed complexes that also containedα1 and γ2 subunits. Taken together these separate lines of evidence suggest that the effects of GABA in central neurons can be mediated by heteromeric complexes of GABA A and GABA C receptor subunits.
Publisher: Wiley
Date: 06-06-2002
DOI: 10.1046/J.1471-4159.2002.00920.X
Abstract: Although originally cloned from rat brain, the P2X7 receptor has only recently been localized in neurones, and functional responses mediated by these neuronal P2X7 receptors (P2X7 R) are largely unknown. Here we studied the effect of P2X7 R activation on the release of neurotransmitters from superfused rat hippoc al slices. ATP (1-30 mm) and other ATP analogues elicited concentration-dependent [3 H]GABA outflow, with the following rank order of potency: benzoylbenzoylATP (BzATP) > ATP > ADP. PPADS, the non-selective P2-receptor antagonist (3-30 microm), Brilliant blue G (1-100 nm) the P2X7 -selective antagonist and Zn2+ (0.1-30 microm) inhibited, whereas lack of Mg2+ potentiated the response by ATP. In situ hybridization revealed that P2X7 R mRNA is expressed in the neurones of the cell body layers in the hippoc us. P2X7 R immunoreactivity was found in excitatory synaptic terminals in CA1 and CA3 region targeting the dendrites of pyramidal cells and parvalbumin labelled structures. ATP (3-30 microm) and BzATP (0.6-6 microm) elicited concentration-dependent [14 C]glutamate efflux, and blockade of the kainate receptor-mediated transmission by CNQX (10-100 microm) and gadolinium (100 microm), decreased ATP evoked [3 H]GABA efflux. The Na+ channel blocker TTX (1 microm), low temperature (12 degrees C), and the GABA uptake blocker nipecotic acid (1 mm) prevented ATP-induced [3 H]GABA efflux. Brilliant blue G and PPADS also reduced electrical field stimulation-induced [3 H]GABA efflux. In conclusion, P2X7 Rs are localized to the excitatory terminals in the hippoc us, and their activation regulates the release of glutamate and GABA from themselves and from their target cells.
Publisher: Society for Neuroscience
Date: 27-06-2007
Publisher: Oxford University Press (OUP)
Date: 21-10-2022
DOI: 10.1093/BRAINCOMMS/FCAC267
Abstract: Establishing preclinical models of Alzheimer’s disease that predict clinical outcomes remains a critically important, yet to date not fully realized, goal. Models derived from human cells offer considerable advantages over non-human models, including the potential to reflect some of the inter-in idual differences that are apparent in patients. Here we report an approach using induced pluripotent stem cell-derived cortical neurons from people with early symptomatic Alzheimer’s disease where we sought a match between in idual disease characteristics in the cells with analogous characteristics in the people from whom they were derived. We show that the response to amyloid-β burden in life, as measured by cognitive decline and brain activity levels, varies between in iduals and this vulnerability rating correlates with the in idual cellular vulnerability to extrinsic amyloid-β in vitro as measured by synapse loss and function. Our findings indicate that patient-induced pluripotent stem cell-derived cortical neurons not only present key aspects of Alzheimer’s disease pathology but also reflect key aspects of the clinical phenotypes of the same patients. Cellular models that reflect an in idual’s in-life clinical vulnerability thus represent a tractable method of Alzheimer’s disease modelling using clinical data in combination with cellular phenotypes.
Publisher: Oxford University Press (OUP)
Date: 26-07-2006
DOI: 10.1093/NAR/GKL525
Publisher: Cold Spring Harbor Laboratory
Date: 02-12-2008
DOI: 10.1261/RNA.1127009
Abstract: The essential transcriptional repressor REST (repressor element 1-silencing transcription factor) plays central roles in development and human disease by regulating a large cohort of neural genes. These have conventionally fallen into the class of known, protein-coding genes recently, however, several noncoding microRNA genes were identified as REST targets. Given the widespread transcription of messenger RNA-like, noncoding RNAs (“macroRNAs”), some of which are functional and implicated in disease in mammalian genomes, we sought to determine whether this class of noncoding RNAs can also be regulated by REST. By applying a new, unbiased target gene annotation pipeline to computationally discovered REST binding sites, we find that 23% of mammalian REST genomic binding sites are within 10 kb of a macroRNA gene. These putative target genes were overlooked by previous studies. Focusing on a set of 18 candidate macroRNA targets from mouse, we experimentally demonstrate that two are regulated by REST in neural stem cells. Flanking protein-coding genes are, at most, weakly repressed, suggesting specific targeting of the macroRNAs by REST. Similar to the majority of known REST target genes, both of these macroRNAs are induced during nervous system development and have neurally restricted expression profiles in adult mouse. We observe a similar phenomenon in human: the DiGeorge syndrome-associated noncoding RNA, DGCR5 , is repressed by REST through a proximal upstream binding site. Therefore neural macroRNAs represent an additional component of the REST regulatory network. These macroRNAs are new candidates for understanding the role of REST in neuronal development, neurodegeneration, and cancer.
Publisher: Elsevier BV
Date: 12-2006
Publisher: Wiley
Date: 20-07-2006
DOI: 10.1111/J.1471-4159.2006.04010.X
Abstract: Release of distinct cellular cargoes in response to specific stimuli is a process fundamental to all higher eukaryotes and controlled by the regulated secretory pathway (RSP). However, the mechanism by which genes involved in the RSP are selectively expressed, leading to the establishment and appropriate functioning of regulated secretion remaining largely unknown. Using the rat pheochromocytoma cell line PC12, we provide evidence that, by controlling expression of many genes involved in the RSP, the transcriptional repressor REST can regulate this pathway and hence the neurosecretory phenotype. Introduction of REST transgenes into PC12 cells leads to the repression of many genes, the products of which are involved in regulated secretion. Moreover, chromatin immunoprecipitation assays show that many of the repressed genes recruit the recombinant REST protein to RE1 sites within their promoters and abrogation of REST function leads to reactivation of these transcripts. In addition to the observed transcriptional effects, PC12 cells expressing REST have fewer secretory granules and a reduction in the ability to store and release noradrenaline. Furthermore, an important trigger for synaptic release, influx of calcium through voltage-operated calcium channels, is compromised. This is the first demonstration of a transcription factor that directly controls expression of many major components of the RSP and provides further insight into the function of REST.
Publisher: Cold Spring Harbor Laboratory
Date: 11-11-2021
DOI: 10.1101/2021.11.09.467891
Abstract: Establishing preclinical models of Alzheimer’s disease that predict clinical outcomes remains a critically important, yet to date not fully realised, goal. Models derived from human cells offer considerable advantages over non-human models, including the potential to reflect some of the inter-in idual differences that are apparent in patients. Here we report an approach using induced pluripotent stem cell-derived cortical neurons from people with early symptomatic Alzheimer’s disease where we sought a match between in idual disease characteristics in cells with analogous characteristics in the people from whom they were derived. We show that the response to amyloid-β burden in life, as measured by cognitive decline and brain activity levels, varies between in iduals and this vulnerability rating correlates with the in idual cellular vulnerability to extrinsic amyloid-β in vitro as measured by synapse loss and function. Our findings indicate that patient induced pluripotent stem cell-derived cortical neurons not only present key aspects of Alzheimer’s disease pathology, but also reflect key aspects of the clinical phenotypes of the same patients. Cellular models that reflect an in idual’s in-life clinical vulnerability thus represent a tractable method of Alzheimer’s disease modelling using clinical data in combination with cellular phenotypes.
Publisher: Springer Science and Business Media LLC
Date: 11-2002
DOI: 10.1038/420042A
Publisher: Oxford University Press (OUP)
Date: 17-07-2019
DOI: 10.1093/HMG/DDZ165
Abstract: The Finnish-variant late infantile neuronal ceroid lipofuscinosis, also known as CLN5 disease, is caused by mutations in the CLN5 gene. Cln5 is strongly expressed in the developing brain and expression continues into adulthood. CLN5, a protein of unknown function, is implicated in neurodevelopment but detailed investigation is lacking. Using Cln5−/− embryos of various ages and cells harvested from Cln5−/− brains we investigated the hitherto unknown role of Cln5 in the developing brain. Loss of Cln5 results in neuronal differentiation deficits and delays in interneuron development during in utero period. Specifically, the radial thickness of dorsal telencephalon was significantly decreased in Cln5−/− mouse embryos at embryonic day 14.5 (E14.5), and expression of Tuj1, an important neuronal marker during development, was down-regulated. An interneuron marker calbindin and a mitosis marker p-H3 showed down-regulation in ganglionic eminences. Neurite outgrowth was compromised in primary cortical neuronal cultures derived from E16 Cln5−/− embryos compared with WT embryos. We show that the developmental deficits of interneurons may be linked to increased levels of the repressor element 1-silencing transcription factor, which we report to bind to glutamate decarboxylase (Gad1), which encodes GAD67, a rate-limiting enzyme in the production of gamma-aminobutyric acid (GABA). Indeed, adult Cln5−/− mice presented deficits in hippoc al parvalbumin-positive interneurons. Furthermore, adult Cln5−/− mice presented deficits in hippoc al parvalbumin-positive interneurons and showed age-independent cortical hyper excitability as measured by electroencephalogram and auditory-evoked potentials. This study highlights the importance of Cln5 in neurodevelopment and suggests that in contrast to earlier reports, CLN5 disease is likely to develop during embryonic stages.
Publisher: Society for Neuroscience
Date: 15-09-2001
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Noel Buckley.