Cherie Stayner - Academia.edu (original) (raw)

Papers by Cherie Stayner

Nephrology (Carlton, Vic.), 2015

Cilia, 2012

Defects in primary cilia structure or function result in both common and rare ciliopathies. We ha... more Defects in primary cilia structure or function result in both common and rare ciliopathies. We have characterized an ovine model of Meckel Gruber Syndrome involving widespread dysplastic changes and cystogenesis in multiple organs. SNPchip screening identified an MKS3 gene defect, while sequencing identified two missense mutations (I680N and I686S) in a conserved region coding for an intracellular loop of meckelin. We report on the nature and extent of renal primary cilia defects associated with this unique model. Columnar, cuboidal and squamous epithelia lined small cysts (1-5mm) distributed throughout the kidney, with extensive interstitial fibrosis. Immunohistochemical and SEM studies revealed a low incidence of dysmorphic epithelia cilia, including many detached near the base and shed into the cysts. Meckelin staining showed extensive vesiculation within epithelia and interstitial fibroblasts, it co-localised to the base and along the length of both attached and shed cilia, and it labeled microvesicles within cysts. In cultured fibroblasts, cilia were highly dysmorphic, ciliary incidence was similar (44% controls; 48% mutants), but ciliary length was significantly longer in mutants (17.8±1.4 cf 8.3±0.7µm; p < 0.05). Golgi markers showed extensive cytoplasmic vesiculation in mutant fibroblasts, while TEM showed Golgi distention, multivesicular bodies, intraciliary vesicles, and extracellular microvesicles. Primary cilia structure was significantly compromised in this large animal model including irregular morphology, length variation, intraciliary vesicles, cilia shedding, Golgi distention, formation of multivesicular bodies, and microvesicle release. Results suggest that disruption to the conserved isoleucines of meckelin compromises protein structure and ciliary function in this model of Meckel Gruber syndrome.

Journal of the American Society of Nephrology : JASN, 2002

Polycystin-L (PCL), the third member of the polycystin family of proteins, functions as a Ca2+-mo... more Polycystin-L (PCL), the third member of the polycystin family of proteins, functions as a Ca2+-modulated nonselective cation channel when expressed in Xenopus oocytes. Polycystin-1 and -2 are mutated in autosomal-dominant polycystic kidney disease (ADPKD), but the role of PCL in disease has not been determined. In this study, an anti-peptide polyclonal antiserum was generated against the carboxyl terminal domain of human PCL and used to determine the patterns of expression and distribution of PCL by indirect immunofluorescence in both developing and adult mice. The results show that PCL is predominantly expressed in adult mouse tissues and has a more restricted pattern of expression than either polycystin-1 or -2. In the kidney, PCL expression was first detected at E16, and levels increased into adulthood. Localization of PCL was predominantly found in the apical region of the principal cells of inner medullary collecting ducts. PCL was also found in discrete cell types of the retin...

Comparative medicine, 2002

The pathogenesis of polycystic kidney disease (PKD) has not been firmly established; however, our... more The pathogenesis of polycystic kidney disease (PKD) has not been firmly established; however, our current knowledge of cystogenesis and human cystic disease has been greatly advanced by a variety of animal models of PKD. To study the onset and degree of cyst formation in PKD mouse models without requiring sacrifice of these animals, we have initiated magnetic resonance imaging (MRI) studies of the juvenile cystic kidney (jck) mouse model. The MRI experiments were performed by use of a Bruker 8.5 T system, on seven-week-old mice that were homozygous for the recessive jck mutation and that manifested PKD. Kidney volume was measured, using three-dimensional segmentation postprocessing techniques. The MR images of the enlarged kidneys from affected mice had regions of high signal intensity, with a radial distribution, which reflected the dilated collecting ducts observed in the corresponding histologic slices. The volume of PKD-affected kidney was about 4 times greater than that of the ...

F1000Prime Reports, 2014

Gene dosage effects have emerged as playing a central role in the pathogenesis of polycystic kidn... more Gene dosage effects have emerged as playing a central role in the pathogenesis of polycystic kidney disease. Yet, how gene dosage can ultimately have an impact on the formation of kidney cysts remains unknown. In this commentary we review the evidence for the role of gene dosage effects versus the &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot;2-hit&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;quot; mutation model in polycystic kidney disease (PKD), and also discuss how gene networks may potentially make intertwined contributions to PKD.

Trends in Pharmacological Sciences, 2001

... Permissions & Reprints. Research update. Polycystin channels and kidney disease. Cherie S... more ... Permissions & Reprints. Research update. Polycystin channels and kidney disease. Cherie Stayner and Jing Zhou E-mail The Corresponding Author. ... Nat. Genet. 10 (1995), pp. 151160. Full Text via CrossRef | View Record in Scopus | Cited By in Scopus (456). ...

Nephrology, 2012

Recessive PKD can result in end-stage renal disease (ESRD) within the first decade, whereas autos... more Recessive PKD can result in end-stage renal disease (ESRD) within the first decade, whereas autosomal dominant PKD (ADPKD), caused by mutations in the PKD1 or PKD2 gene, typically leads to ESRD by the fifth decade of life. Inhibition of mTOR signalling was recently found to halt cyst formation in adult ADPKD mice. In contrast, no studies have investigated potential treatments to prevent cyst formation in utero in recessive PKD. Given that homozygous Pkd1 mutant mice exhibit cyst formation in utero, we decided to investigate whether mTOR inhibition in utero ameliorates kidney cyst formation in foetal Pkd1 homozygous mutant mice.

Journal of the American Society of Nephrology, 2003

In humans, PAX2 haploinsufficiency causes renal-coloboma syndrome (RCS) involving eye abnormaliti... more In humans, PAX2 haploinsufficiency causes renal-coloboma syndrome (RCS) involving eye abnormalities, renal hypoplasia, and renal failure in early life. The authors previously showed that heterozygous mutant Pax2 mice have smaller kidneys with fewer nephrons, associated with elevated apoptosis in the ureteric bud (UB). However, PAX2 may have a variety of developmental functions such as effects on cell fate and differentiation. To determine whether apoptosis alone is sufficient to cause a UB branching deficit, the authors targeted a pro-apoptotic gene (Baxalpha) to the embryonic kidney under the control of human PAX2 regulatory elements. The exogenous PAX2 promoter directed Baxalpha gene expression specifically to the developing kidney UB, eye, and mid/hindbrain. At E15.5 PAX2Promoter-Baxalpha fetal mice exhibited renal hypoplasia, elevated UB apoptosis, and retinal defects, mimicking the phenotype observed in RCS. The kidneys of E15.5 PAX2Promoter-Baxalpha fetal mice were 55% smaller than those of wild-type fetal mice, and they contained 70% of the normal level of UB branching. The data indicate that loss of Pax2 anti-apoptotic activity is sufficient to account for the reduced UB branching observed in RCS and suggest that elevated UB apoptosis may be a key process responsible for renal hypoplasia. The authors propose a morphogenic unit model in which cell survival influences the rate of UB branching and determines final nephron endowment.

Journal of Biological Chemistry, 1998

PAX2, a member of the PAX gene family of developmental transcription factors, is expressed at hig... more PAX2, a member of the PAX gene family of developmental transcription factors, is expressed at high levels in the developing eyes, ears, central nervous and urogenital systems, as well as in Wilms' tumor and renal cell carcinoma. Expression of PAX2 in the urogenital system is associated with proliferating cells of the ureteric bud and the differentiating nephrogenic mesenchyme. To date, little is known about the molecular mechanisms controlling the regulation of PAX2 expression. This report describes the cloning and characterization of the human PAX2 gene promoter and localization of the transcription start sites in fetal kidney and Wilms' tumor. We identified two transcription start sites in a Wilms' tumor sample, which were found to be different from that in fetal kidney. The activity of a deletion series of the PAX2 promoter was assessed in NIH-3T3, COS-7, 293, and Madin-Darby canine kidney cells. Although some differences were observed in the activity of each promoter construct, the profile of activity for the promoter fragment series was similar in each experiment, regardless of cell type. The WT1 tumor suppressor protein, which has previously been shown to repress murine Pax2 expression in vitro, was shown to also repress expression from the human PAX2 promoter.

Human Molecular Genetics, 2006

Mutations in PKD1 cause dominant polycystic kidney disease (PKD), characterized by large fluid-fi... more Mutations in PKD1 cause dominant polycystic kidney disease (PKD), characterized by large fluid-filled kidney cysts in adult life, but the molecular mechanism of cystogenesis remains obscure. Ostrom et al.[ Dev. Biol., 219, 250-258 (2000)] showed that reduced dosage of Pax2 caused increased apoptosis, and ameliorated cystogenesis in Cpk mutant mice with recessive PKD. Pax2 is expressed in condensing metanephrogenic mesenchyme and arborizing ureteric bud, and plays an important role in kidney development. Transient Pax2 expression during fetal kidney mesenchyme-to-epithelial transition, as well as in nascent tubules, is followed by marked down-regulation of Pax2 expression. Here, we show that in humans with PKD, as well as in Pkd1 del34/del34 mutant mice, Pax2 was expressed in cyst epithelial cells, and facilitated cyst growth in Pkd1 del34/del34 mutant mice. In Pkd1 del34/del34 mutant kidneys, the expression of Pax2 persisted in nascent collecting ducts. In contrast, homozygous Pkd1 del34/del34 fetal mice carrying mutant Pax2 exhibited ameliorated cyst growth, although reduced cystogenesis was not associated with increased apoptosis. Pax2 expression was attenuated in nascent collecting ducts and absent from remnant cysts of Pkd1 del34/del34 /Pax2 1Neu/1 mutant mice. To investigate whether the Pkd1 gene product, Polycystin-1, regulates Pax2,M D C Kc e l l s were engineered constitutively expressing wild-type Pkd1; Pax2 protein levels and promoter activity were both repressed in MDCK cells over-expressing Pkd1, but not in cells without transgenic Pkd1. These data suggest that polycystin-1-deficient tubular epithelia persistently express Pax2 in ADPKD, and that Pax2 or its pathway may be an appropriate target for the development of novel therapies for ADPKD.

Journal of Reproduction and Development, 2012

Genomic imprinting confers allele-specific expression in less than 1% of genes, in a parent-of-or... more Genomic imprinting confers allele-specific expression in less than 1% of genes, in a parent-of-origin specific fashion. In humans and mice the Peg1/Mest gene (Mest) is maternally repressed, and paternally expressed. Mest is expressed in embryogenic mesoderm-derived tissues and in adult brain, and paternal mutations in Mest lead to growth retardation and defective maternal behaviour. Despite our current understanding of mechanisms associated with the establishment of imprinting of Mest and other imprinted genes, it is unclear to what extent Mest imprinting needs to be maintained in adult tissues. Aberrations of imprinting are known to occur in certain rare syndromes, and involve either inherited mutations, or constitutive epigenetic alterations occurring soon after fertilization. Imprinting abnormalities may also occur in the aging somatic tissues of adult individuals. Here we report an occurrence of post-embryonic somatic variability of Mest allelic expression in a colony of mice where heterozygotes at the imprinted Mest locus for a mutation inherited from the father spontaneously expressed the normally silenced allele from the mother. In addition, a newly acquired ability to overcome the deficit in maternal reproductive behaviour had occurred in the mutant mice, but this appeared not to be directly linked to the Mest mutation. Our results suggest that at least one allele of Mest expression is required in the somatic tissues of adult individuals and that under certain conditions (such as in the presence of a Mest insertional mutation or in an altered genetic background), somatically acquired alterations of allelic expression at the Mest locus may occur.