ORCID Profile
0000-0002-4401-1946
Current Organisation
James Cook University
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: The Company of Biologists
Date: 15-09-2009
DOI: 10.1242/DEV.032334
Abstract: Connexin 43 knockout (Cx43 KO) mice exhibit conotruncal malformations and coronary artery defects. We observed epicardial blisters in the Cx43 KO hearts that suggest defects in epicardial epithelial-mesenchymal transformation(EMT), a process that generates coronary vascular progenitors. Analysis using a three-dimensional collagen gel invasion assay showed that Cx43 KO epicardial cells are less invasive and that, unlike wild-type epicardial cells, they fail to organize into thin vessel-like projections. Examination of Cx43 KO hearts using Wt1 as an epicardial marker revealed a disorganized pattern of epicardial cell infiltration. Time-lapse imaging and motion analysis using epicardial explants showed a defect in directional cell migration. This was associated with changes in the actin/tubulin cytoskeleton. A defect in cell polarity was indicated by a failure of the microtubule-organizing center to align with the direction of cell migration. Forced expression of Cx43 constructs in epicardial explants showed the Cx43 tubulin-binding domain is required for Cx43 modulation of cell polarity and cell motility. Pecam staining revealed early defects in remodeling of the primitive coronary vascular plexuses in the Cx43 KO heart. Together, these findings suggest an early defect in coronary vascular development arising from a global perturbation of the cytoarchitecture of the cell. Consistent with this, we found aberrant myocardialization of the outflow tract, a process also known to be EMT dependent. Together, these findings suggest cardiac defects in the Cx43 KO mice arise from the disruption of cell polarity, a process that may be dependent on Cx43-tubulin interactions.
Publisher: Frontiers Media SA
Date: 11-02-2015
Publisher: Frontiers Media SA
Date: 16-10-2014
Publisher: Public Library of Science (PLoS)
Date: 26-11-2013
Publisher: American Thoracic Society
Date: 11-2014
Publisher: SAGE Publications
Date: 16-07-2015
Publisher: Public Library of Science (PLoS)
Date: 14-10-2011
Publisher: The Company of Biologists
Date: 15-10-2008
DOI: 10.1242/JCS.032847
Abstract: Syntaxin 4 is a component of the SNARE complex that regulates membrane docking and fusion. Using a yeast two-hybrid screen, we identify a novel interaction between syntaxin 4 and cytoplasmic murine CENPF, a protein previously demonstrated to associate with the microtubule network and SNAP-25. The binding domain for syntaxin 4 in CENPF was defined by yeast two-hybrid assay and co-immunoprecipitation. Confocal analyses in cell culture reveal a high degree of colocalization between endogenously expressed proteins in interphase cells. Additionally, the endogenous SNARE proteins can be isolated as a complex with CENPF in immunoprecipitation experiments. Further analyses demonstrate that murine CENPF and syntaxin 4 colocalize with components of plasma membrane recycling: SNAP-25 and VAMP2. Depletion of endogenous CENPF disrupts GLUT4 trafficking whereas expression of a dominant-negative form of CENPF inhibits cell coupling. Taken together, these studies demonstrate that CENPF provides a direct link between proteins of the SNARE system and the microtubule network and indicate a erse role for murine CENPF in vesicular transport.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 09-2013
Publisher: American Society for Clinical Investigation
Date: 09-03-2017
Publisher: Public Library of Science (PLoS)
Date: 26-02-2016
Publisher: The Company of Biologists
Date: 2010
DOI: 10.1242/DMM.006262
Abstract: Meckel-Gruber syndrome (MKS) is a recessive disorder resulting in multiple birth defects that are associated with mutations affecting ciliogenesis. We recovered a mouse mutant with a mutation in the Mks1 gene (Mks1del64-323) that caused a 260-amino-acid deletion spanning nine amino acids in the B9 domain, a protein motif with unknown function conserved in two other basal body proteins. We showed that, in wild-type cells, Mks1 was localized to the mother centriole from which the cilium was generated. However, in mutant Mks1del64-323 cells, Mks1 was not localized to the centriole, even though it maintained a punctate distribution. Resembling MKS patients, Mks1 mutants had craniofacial defects, polydactyly, congenital heart defects, polycystic kidneys and randomized left-right patterning. These defects reflected disturbance of functions subserved by motile and non-motile cilia. In the kidney, glomerular and tubule cysts were observed along with short cilia, and cilia were reduced in number to a near-complete loss. Underlying the left-right patterning defects were fewer and shorter nodal cilia, and analysis with fluorescent beads showed no directional flow at the embryonic node. In the cochlea, the stereocilia were mal-patterned, with the kinocilia being abnormally positioned. Together, these defects suggested disruption of planar cell polarity, which is known to regulate node, kidney and cochlea development. In addition, we also showed that Shh signaling was disrupted. Thus, in the neural tube, the floor plate was not specified posteriorly even as expression of the Shh mediator Gli2 increased. By contrast, the Shh signaling domain was expanded in the anterior neural tube and anterior limb bud, consistent with reduced Gli3-repressor (Gli3R) function. The latter probably accounted for the preaxial digit duplication exhibited by the Mks1del64-323 mutants. Overall, these findings indicate that centriole localization of Mks1 is required for ciliogenesis of motile and non-motile cilia, but not for centriole assembly. On the basis of these results, we hypothesize a role for the B9 domain in mother centriole targeting, a possibility that warrants further future investigations.
Publisher: Elsevier BV
Date: 03-2003
DOI: 10.1016/S0303-7207(02)00417-3
Abstract: Amounts of betaA-activin, betaC-activin, activin receptor subunits ActRIIA and ActRIIB mRNA, and betaA- and betaC-activin subunit protein immunoreactivity were investigated in male Lewis rats, either untreated or after 5 or 10 weeks of CCl(4) treatment to induce cirrhosis. Apoptosis was assessed histologically and with an in situ cell death detection kit (TUNEL). Reverse transcription and polymerase chain reaction were used to evaluate mRNA levels. Activin betaA- and betaC-subunit immunoreactivity was studied by immunohistochemistry using specific monoclonal antibodies. Hepatocellular apoptosis (P<0.001), increased betaA- and betaC-activin mRNAs (three- to fourfold P<0.01) and increased betaA- and betaC-activin tissue immunoreactivity were evident, whereas ActRIIA mRNA concentrations fell (30% P<0.01) after 5 weeks of CCl(4) treatment. The mRNA concentrations at 10 weeks were not significantly different from controls, despite extensive hepatic nodule formation. We conclude that the increased activin subunit expression is associated with apoptosis, rather than hepatic fibrosis and nodule formation.
Publisher: Cold Spring Harbor Laboratory
Date: 07-06-2023
DOI: 10.1101/2023.06.07.544132
Abstract: Ciliopathies are associated with wide spectrum of structural birth defects (SBD), indicating important roles for cilia in development. Here we provide novel insights into the temporospatial requirement for cilia in SBDs arising from deficiency in Ift140 , an intraflagellar transport protein regulating ciliogenesis. Ift140 deficient mice exhibit cilia defects accompanied by wide spectrum of SBDs including macrostomia (craniofacial defects), exencephaly, body wall defects, tracheoesophageal fistula, randomized heart looping, congenital heart defects (CHD), lung hypoplasia, renal anomalies, and polydactyly. Tamoxifen inducible CAG-Cre deletion of a floxed Ift140 allele between E5.5 to 9.5 revealed early requirement for Ift140 in left-right heart looping regulation, mid to late requirement for cardiac outflow septation and alignment, and late requirement for craniofacial development and body wall closure. Surprisingly, CHD was not observed with four Cre drivers targeting different lineages essential for heart development, but craniofacial defects and omphalocele were observed with Wnt1-Cre targeting neural crest and Tbx18-Cre targeting epicardial lineage and rostral sclerotome through which trunk neural crest cells migrate. These findings revealed cell autonomous role of cilia in cranial/trunk neural crest mediated craniofacial and body wall closure defects, while non-cell autonomous multi-lineage interactions underlie CHD pathogenesis, revealing unexpected developmental complexity for CHD associated with ciliopathy.
Publisher: Oxford University Press (OUP)
Date: 15-04-2015
DOI: 10.1093/HMG/DDV137
Publisher: Proceedings of the National Academy of Sciences
Date: 17-06-2008
Abstract: Bves is an integral membrane protein with no determined function and no homology to proteins outside of the Popdc family. It is widely expressed throughout development in myriad organisms. Here, we demonstrate an interaction between Bves and guanine nucleotide exchange factor T (GEFT), a GEF for Rho-family GTPases. This interaction represents the first identification of any protein that has a direct physical interaction with any member of the Popdc family. Bves and GEFT are shown to colocalize in adult skeletal muscle. We also demonstrate that exogenous expression of Bves reduces Rac1 and Cdc42 activity levels while not affecting levels of active RhoA. Consistent with a repression of Rac1 and Cdc42 activity, we show changes in speed of cell locomotion and cell roundness also result from exogenous expression of Bves. Modulation of Rho-family GTPase signaling by Bves would be highly consistent with previously described phenotypes occurring upon disruption of Bves function in a wide variety of model systems. Therefore, we propose Bves as a novel regulator of the Rac1 and Cdc42 signaling cascades.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 05-08-2015
DOI: 10.1126/SCITRANSLMED.AAA1233
Abstract: An objective, computational method to quantitatively identify ciliary motion in digital videos of cells from patients with ciliopathies can be used for diagnosis.
Publisher: SPIE
Date: 26-03-2013
DOI: 10.1117/12.2004860
Publisher: Elsevier
Date: 2010
Publisher: Elsevier BV
Date: 05-2005
Publisher: Springer Science and Business Media LLC
Date: 05-10-2015
DOI: 10.1038/NG.3410
Publisher: Springer Science and Business Media LLC
Date: 25-03-2015
DOI: 10.1038/NATURE14269
Publisher: Springer Science and Business Media LLC
Date: 2008
Publisher: Elsevier BV
Date: 04-2014
DOI: 10.1016/J.JTCVS.2013.06.018
Abstract: Congenital heart disease (CHD) and heterotaxy patients have increased postoperative and respiratory complications. We recently showed CHD-heterotaxy patients can have respiratory ciliary dysfunction (CD) similar to that associated with primary ciliary dyskinesia, including low nasal nitric oxide and abnormal ciliary motion. In this study, we investigated whether CHD-heterotaxy patients with CD may have worse postsurgical outcomes. We examined postsurgical outcome in 13 heterotaxy-CHD patients with CD (25 surgeries), compared with 14 heterotaxy-CHD patients without CD (27 surgeries). Outcome data were collected for each surgery, including respiratory complications, tracheostomy, use of inhaled β-agonists or nitric oxide, length of hospital stay, days on ventilator, and death. The CD versus the no-CD CHD cohorts had similar Risk Adjustment in Congenital Heart Surgery-1 risk categories, repair track, age at surgery, and follow-up evaluation times. Respiratory complications (76% vs 37% P = .006), need for tracheostomy (16% vs 0% P = .047), and use of inhaled β-agonists (64% vs 11% P = .0001) all were increased significantly in heterotaxy-CHD patients with CD. No significant differences were detected in postoperative hospital stay, days on mechanical ventilation, or surgical mortality. A trend toward increased mortality for the CD group beyond the postoperative period was observed (33% vs 0% P = .055) in patients younger than age 10 years. Our findings showed that heterotaxy-CHD patients with CD may have increased risks for respiratory deficiencies. Overall, there was a trend toward increased mortality in CD patients with intermediate follow-up evaluation. Because β-agonists are known to increase ciliary beat frequency, presurgical screening for CD and perioperative treatment of CD patients with inhaled β-agonists may improve postoperative outcomes and survival.
Publisher: Elsevier BV
Date: 08-2013
Publisher: Springer Science and Business Media LLC
Date: 21-07-2013
DOI: 10.1038/NG.2707
Publisher: MyJove Corporation
Date: 08-08-2013
DOI: 10.3791/50343
Publisher: Elsevier BV
Date: 03-2010
DOI: 10.1016/J.ECHO.2009.11.024
Abstract: The authors conducted an ultrasound interrogation of a mutant mouse model with a Dnah5 mutation to determine whether cardiac mechanics may be affected by reversal of cardiac situs. This mutant is a bona fide model of primary ciliary dyskinesia, with surviving homozygous mice showing either situs solitus (SS) or situs inversus totalis (SI). High-frequency ultrasound interrogations of 27 neonatal and infant Dnah5 mutant mice, 16 with SS and 11 with SI, were conducted using an ultra-high-frequency biomicroscope. Electrocardiographic and respiratory gating were used to reconstruct high-resolution two-dimensional cines at 1,000 Hz, with speckle-tracking echocardiography used to further analyze midchamber and apical rotation. All SS mice exhibited the expected counterclockwise apical rotation as viewed caudocranially, and surprisingly, the same counterclockwise motion was also observed in SI mice. Speckle-tracking analysis confirmed counterclockwise systolic rotation in both SS and SI mice, and this increased in magnitude from the subepicardium to the endocardium and from the papillary muscles to the apex. The magnitude of apical endocardial rotation was not different for SS and SI mice (5.64+/-0.75 degrees and 5.76+/-1.90 degrees, respectively, P=.93). The anatomic segments responsible for the largest components of apical endocardial systolic rotation differed between the SS and SI hearts (P=.004). In both, the two largest contributors to rotation were offset 180 degrees from each other, but the anatomic regions differed between them. In SS hearts, maximal regional rotation occurred at the anterior mid-septum and posterolateral free wall, while in SI hearts, it was derived from the posterior septum and the anterolateral free wall. Analysis by episcopic fluorescence image capture histology of representative SI and SS mice showed normal intracardiac and segmental anatomy ({S,D,S} or {I,L,I}) without intracardiac defects. These results show that mirror-image cardiac looping did not result in mirror-image rotation of the morphologic left ventricle. These findings suggest that further studies are warranted to evaluate whether fiber orientation and cardiac mechanics may be abnormal in in iduals with reversal of cardiac situs. The results of this study indicate that cardiac looping and myofiber orientation may be independently regulated.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-2013
DOI: 10.1161/CIRCIMAGING.113.000279
Abstract: Mice are well suited for modeling human congenital heart disease (CHD), given their 4-chamber cardiac anatomy. However, mice with CHD invariably die prenatally/neonatally, causing CHD phenotypes to be missed. Therefore, we investigated the efficacy of noninvasive microcomputed tomography (micro-CT) to screen for CHD in stillborn/fetal mice. These studies were performed using chemically mutagenized mice expected to be enriched for birth defects, including CHD. Stillborn/fetal mice obtained from the breeding of N -ethyl- N -nitrosourea mutagenized mice were formalin-fixed and stained with iodine, then micro-CT scanned. Those diagnosed with CHD and some CHD-negative pups were necropsied. A subset of these were further analyzed by histopathology to confirm the CHD/no-CHD diagnosis. Micro-CT scanning of 2105 fetal/newborn mice revealed an abundance of ventricular septal defects (n=307). Overall, we observed an accuracy of 89.8% for ventricular septal defect diagnosis. Outflow tract anomalies identified by micro-CT included double outlet right ventricle (n=36), transposition of the great arteries (n=14), and persistent truncus arteriosus (n=3). These were diagnosed with a 97.4% accuracy. Aortic arch anomalies also were readily detected with an overall 99.6% accuracy. This included right aortic arch (n=28) and coarctation/interrupted aortic arch (n=12). Also detected by micro-CT were atrioventricular septal defects (n=22), tricuspid hypoplasia/atresia (n=13), and coronary artery fistulas (n=16). They yielded accuracies of 98.9%, 100%, and 97.8%, respectively. Contrast enhanced micro-CT imaging in neonatal/fetal mice can reliably detect a wide spectrum of CHD. We conclude that micro-CT imaging can be used for routine rapid assessments of structural heart defects in fetal/newborn mice.
Publisher: IEEE
Date: 03-2011
Publisher: PeerJ
Date: 27-02-2023
DOI: 10.7717/PEERJ.14899
Abstract: COVID-19 has seen the propagation of alternative remedies to treat respiratory disease, such as nebulization of hydrogen peroxide (H 2 O 2 ). As H 2 O 2 has known cytotoxicity, it was hypothesised that H 2 O 2 inhalation would negatively impact respiratory cilia function. To test this hypothesis, mouse tracheal s les were incubated with different H 2 O 2 concentrations (0.1–1%) then cilia motility, cilia generated flow, and cell death was assessed 0–120 min following H 2 O 2 treatment. 0.1–0.2% H 2 O 2 caused immediate depression of cilia motility and complete cessation of cilia generated flow. Higher H 2 O 2 concentrations (≥0.5%) caused immediate complete cessation of cilia motility and cilia generated flow. Cilia motility and flow was restored 30 min after 0.1% H 2 O 2 treatment. Cilia motility and flow remained depressed 120 min after 0.2–0.5% H 2 O 2 treatment. No recovery was seen 120 min after treatment with ≥1% H 2 O 2 . Live/dead staining revealed that H 2 O 2 treatment caused preferential cell death of ciliated respiratory epithelia over non-ciliated epithelia, with 1% H 2 O 2 causing 35.3 ± 7.0% of the ciliated epithelia cells to die 120 min following initial treatment. This study shows that H 2 O 2 treatment significantly impacts respiratory cilia motility and cilia generated flow, characterised by a significant impairment in cilia motility even at low concentrations, the complete cessation of cilia motility at higher doses, and a significant cytotoxic effect on ciliated respiratory epithelial cells by promoting cell death. While this data needs further study using in vivo models, it suggests that extreme care should be taken when considering treating respiratory diseases with nebulised H 2 O 2 .
Publisher: MyJove Corporation
Date: 04-08-2016
DOI: 10.3791/54401
Publisher: Elsevier BV
Date: 11-2014
Publisher: Proceedings of the National Academy of Sciences
Date: 03-03-2009
Abstract: Forward genetic screens with ENU ( N -ethyl- N -nitrosourea) mutagenesis can facilitate gene discovery, but mutation identification is often difficult. We present the first study in which an ENU- induced mutation was identified by massively parallel DNA sequencing. This mutation causes heterotaxy and complex congenital heart defects and was mapped to a 2.2-Mb interval on mouse chromosome 7. Massively parallel sequencing of the entire 2.2-Mb interval identified 2 single-base substitutions, one in an intergenic region and a second causing replacement of a highly conserved cysteine with arginine (C193R) in the gene Megf8. Megf8 is evolutionarily conserved from human to fruit fly, and is observed to be ubiquitously expressed. Morpholino knockdown of Megf8 in zebrafish embryos resulted in a high incidence of heterotaxy, indicating a conserved role in laterality specification. Megf8 C193R mouse mutants show normal breaking of symmetry at the node, but Nodal signaling failed to be propagated to the left lateral plate mesoderm. Videomicroscopy showed nodal cilia motility, which is required for left–right patterning, is unaffected. Although this protein is predicted to have receptor function based on its amino acid sequence, surprisingly confocal imaging showed it is translocated into the nucleus, where it is colocalized with Gfi1b and Baf60C, two proteins involved in chromatin remodeling. Overall, through the recovery of an ENU-induced mutation, we uncovered Megf8 as an essential regulator of left–right patterning.
Publisher: American Physiological Society
Date: 15-05-2012
DOI: 10.1152/AJPHEART.01118.2011
Abstract: Complex congenital heart disease (CHD) is often seen in conjunction with heterotaxy, the randomization of left-right visceral organ situs. However, the link between cardiovascular morphogenesis and left-right patterning is not well understood. To elucidate the role of left-right patterning in cardiovascular development, we examined situs anomalies and CHD in mice with a loss of function allele of Dnaic1, a dynein protein required for motile cilia function and left-right patterning. Dnaic1 mutants were found to have nodal cilia required for left-right patterning, but they were immotile. Half the mutants had concordant organ situs comprising situs solitus or mirror symmetric situs inversus. The remaining half had randomized organ situs or heterotaxy. Looping of the heart tube, the first anatomical lateralization, showed abnormal L-loop bias rather than the expected D-loop orientation in heterotaxy and nonheterotaxy mutants. Situs solitus/inversus mutants were viable with mild or no defects consisting of azygos continuation and/or ventricular septal defects, whereas all heterotaxy mutants had complex CHD. In heterotaxy mutants, but not situs solitus/inversus mutants, the morphological left ventricle was thin and often associated with a hypoplastic transverse aortic arch. Thus, in conclusion, Dnaic1 mutants can achieve situs solitus or inversus even with immotile nodal cilia. However, the finding of abnormal L-loop bias in heterotaxy and nonheterotaxy mutants would suggest motile cilia are required for normal heart looping. Based on these findings, we propose motile nodal cilia patterns heart looping but heart and visceral organ lateralization is driven by signaling not requiring nodal cilia motility.
Publisher: Springer Science and Business Media LLC
Date: 05-12-2013
Publisher: Springer Science and Business Media LLC
Date: 12-09-2018
Publisher: American Physiological Society
Date: 06-2009
DOI: 10.1152/AJPLUNG.00001.2009
Abstract: Mucociliary clearance in the adult trachea is well characterized, but there are limited data in newborns. Cilia-generated flow was quantified across longitudinal sections of mouse trachea from birth through postnatal day (PND) 28 by tracking fluorescent microsphere speed and directionality. The percentage of ciliated tracheal epithelial cells, as determined by immunohistochemistry, was shown to increase linearly between PND 0 and PND 21 ( R 2 = 0.94). While directionality measurements detected patches of flow starting at PND 3, uniform flow across the epithelia was not observed until PND 7 at a ∼35% ciliated cell density. Flow became established at a maximal rate at PND 9 and beyond. A linear correlation was observed between the percentage of ciliated cells versus flow speed ( R 2 = 0.495) and directionality ( R 2 = 0.975) between PND 0 and PND 9. Cilia beat frequency (CBF) was higher at PND 0 than at all subsequent time points, but cilia beat waveform was not noticeably different. Tracheal epithelia from a mouse model of primary ciliary dyskinesia (PCD) harboring a Mdnah5 mutation showed that ciliated cell density was unaffected, but no cilia-generated flow was detected. Cilia in mutant airways were either immotile or with slow dyssynchronous beat and abnormal ciliary waveform. Overall, our studies showed that the initiation of cilia-generated flow is directly correlated with an increase in epithelial ciliation, with the measurement of directionality being more sensitive than speed for detecting flow. The higher CBF observed in newborn epithelia suggests unique physiology in the newborn trachea, indicating possible clinical relevance to the pathophysiology of respiratory distress seen in newborn PCD patients.
Publisher: Springer Science and Business Media LLC
Date: 20-01-2015
DOI: 10.1038/NCOMMS7023
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2014
DOI: 10.1161/CIRCIMAGING.113.000451
Abstract: Congenital heart disease (CHD) has a multifactorial pathogenesis, but a genetic contribution is indicated by heritability studies. To investigate the spectrum of CHD with a genetic pathogenesis, we conducted a forward genetic screen in inbred mice using fetal echocardiography to recover mutants with CHD. Mice are ideally suited for these studies given that they have the same four-chamber cardiac anatomy that is the substrate for CHD. Ethylnitrosourea mutagenized mice were ultrasound-interrogated by fetal echocardiography using a clinical ultrasound system, and fetuses suspected to have cardiac abnormalities were further interrogated with an ultrahigh-frequency ultrasound biomicroscopy. Scanning of 46 270 fetuses revealed 1722 with cardiac anomalies, with 27.9% dying prenatally. Most of the structural heart defects can be diagnosed using ultrasound biomicroscopy but not with the clinical ultrasound system. Confirmation with analysis by necropsy and histopathology showed excellent diagnostic capability of ultrasound biomicroscopy for most CHDs. Ventricular septal defect was the most common CHD observed, whereas outflow tract and atrioventricular septal defects were the most prevalent complex CHD. Cardiac/visceral organ situs defects were observed at surprisingly high incidence. The rarest CHD found was hypoplastic left heart syndrome, a phenotype never seen in mice previously. We developed a high-throughput, 2-tier ultrasound phenotyping strategy for efficient recovery of even rare CHD phenotypes, including the first mouse models of hypoplastic left heart syndrome. Our findings support a genetic pathogenesis for a wide spectrum of CHDs and suggest that the disruption of left–right patterning may play an important role in CHD.
Publisher: Elsevier BV
Date: 02-2002
Publisher: American Society for Clinical Investigation
Date: 21-11-2007
DOI: 10.1172/JCI33284
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-05-2012
DOI: 10.1161/CIRCULATIONAHA.111.079780
Abstract: Patients with congenital heart disease (CHD) and heterotaxy show high postsurgical morbidity/mortality, with some developing respiratory complications. Although this finding is often attributed to the CHD, airway clearance and left-right patterning both require motile cilia function. Thus, airway ciliary dysfunction (CD) similar to that of primary ciliary dyskinesia (PCD) may contribute to increased respiratory complications in heterotaxy patients. We assessed 43 CHD patients with heterotaxy for airway CD. Videomicrocopy was used to examine ciliary motion in nasal tissue, and nasal nitric oxide (nNO) was measured nNO level is typically low with PCD. Eighteen patients exhibited CD characterized by abnormal ciliary motion and nNO levels below or near the PCD cutoff values. Patients with CD aged years show increased respiratory symptoms similar to those seen in PCD. Sequencing of all 14 known PCD genes in 13 heterotaxy patients with CD, 12 without CD, 10 PCD disease controls, and 13 healthy controls yielded 0.769, 0.417, 1.0, and 0.077 novel variants per patient, respectively. One heterotaxy patient with CD had the PCD causing DNAI1 founder mutation. Another with hyperkinetic ciliary beat had 2 mutations in DNAH11 , the only PCD gene known to cause hyperkinetic beat. Among PCD patients, 2 had known PCD causing CCDC39 and CCDC40 mutations. Our studies show that CHD patients with heterotaxy have substantial risk for CD and increased respiratory disease. Heterotaxy patients with CD were enriched for mutations in PCD genes. Future studies are needed to assess the potential benefit of prescreening and prophylactically treating heterotaxy patients for CD.
Publisher: The Company of Biologists
Date: 15-09-2006
DOI: 10.1242/DEV.02543
Abstract: Connexin 43 knockout (Cx43α1KO) mice have conotruncal heart defects that are associated with a reduction in the abundance of cardiac neural crest cells (CNCs) targeted to the heart. In this study, we show CNCs can respond to changing fibronectin matrix density by adjusting their migratory behavior,with directionality increasing and speed decreasing with increasing fibronectin density. However, compared with wild-type CNCs, Cx43α1KO CNCs show reduced directionality and speed, while CNCs overexpressing Cx43α1 from the CMV43 transgenic mice show increased directionality and speed. Altered integrin signaling was indicated by changes in the distribution of vinculin containing focal contacts, and altered temporal response of Cx43α1KO and CMV43 CNCs to β1 integrin function blocking antibody treatment. High resolution motion analysis showed Cx43α1KO CNCs have increased cell protrusive activity accompanied by the loss of polarized cell movement. They exhibited an unusual polygonal arrangement of actin stress fibers that indicated a profound change in cytoskeletal organization. Semaphorin 3A, a chemorepellent known to inhibit integrin activation, was found to inhibit CNC motility, but in the Cx43α1KO and CMV43 CNCs, cell processes failed to retract with semaphorin 3A treatment. Immunohistochemical and biochemical analyses suggested close interactions between Cx43α1,vinculin and other actin-binding proteins. However, dye coupling analysis showed no correlation between gap junction communication level and fibronectin plating density. Overall, these findings indicate Cx43α1 may have a novel function in mediating crosstalk with cell signaling pathways that regulate polarized cell movement essential for the directional migration of CNCs.
Publisher: Wiley
Date: 06-2022
DOI: 10.14814/PHY2.15349
Publisher: The Company of Biologists
Date: 09-2006
DOI: 10.1242/DEV.02506
Abstract: Connexin 43 knockout (Cx43α1KO) mice exhibit germ cell deficiency,but the underlying cause for the germ cell defect was unknown. Using an Oct4-GFP reporter transgene, we tracked the distribution and migration of primordial germ cells (PGCs) in the Cx43α1KO mouse embryo. Analysis with dye injections showed PGCs are gap-junction-communication competent, with dye coupling being markedly reduced in Cx43α1-deficient PGCs. Time-lapse videomicroscopy and motion analysis showed that the directionality and speed of cell motility were reduced in the Cx43α1KO PGCs. This was observed both in E8.5 and E11.5 embryos. By contrast, PGC abundance did not differ between wild-type and heterozygous/homozygous Cx43α1KO embryos until E11.5, when a marked reduction in PGC abundance was detected in the homozygous Cx43α1KO embryos. This was accompanied by increased PGC apoptosis and increased expression of activated p53. Injection of α-pifithrin, a p53 antagonist, inhibited PGC apoptosis and prevented the loss of PGC. Analysis using a cell adhesion assay indicated a reduction inβ1-integrin function in the Cx43α1KO PGCs. Together with the abnormal activation of p53, these findings suggest the possibility of anoikis-mediated apoptosis. Overall, these findings show Cx43α1 is essential for PGC survival, with abnormal p53 activation playing a crucial role in the apoptotic loss of PGCs in the Cx43α1KO mouse embryos.
Publisher: Wiley
Date: 06-2013
DOI: 10.1002/BDRC.21037
Publisher: Mary Ann Liebert Inc
Date: 2015
Location: United States of America
Location: United States of America
Start Date: 2015
End Date: 2015
Funder: University of New South Wales
View Funded ActivityStart Date: 2009
End Date: 2015
Funder: National Institutes of Health
View Funded ActivityStart Date: 2014
End Date: 2016
Funder: National Institutes of Health
View Funded Activity