Alterations in GRHL2-OVOL2-ZEB1 Axis and Aberrant Activation of Wnt Signaling Lead to Altered Gene Transcription in Posterior Polymorphous Corneal Dystrophy
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ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE126487 | GEO | 2019/04/11
REPOSITORIES: GEO
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Project description:Purpose: To identify the genetic basis of posterior polymorphous corneal dystrophy (PPCD) in families mapped to the PPCD1 locus and in affected individuals without ZEB1 coding region mutations. Methods: The promoter and/or coding regions of OVOL2 were screened in the PPCD family in which linkage analysis established the PPCD1 locus and in 26 PPCD probands who did not harbor a ZEB1 mutation. Copy number variation (CNV) analysis in the PPCD1 and PPCD3 intervals was performed on DNA samples from eight probands using aCGH. Luciferase reporter assays were performed in human corneal endothelial cells to determine the impact of the identified potentially pathogenic variants on OVOL2 promoter activity. Results: OVOL2 screening in the first PPCD1-linked family demonstrated segregation of the c.-307T>C variant with the affected phenotype. In the other 26 probands screened, one heterozygous coding region variant and five promoter region heterozygous variants were identified, though none are likely pathogenic based on allele frequency. Array CGH in the PPCD1 and PPCD3 loci excluded the presence of CNV involving either OVOL2 or ZEB1, respectively. The c.-307T>C variant demonstrated increased promoter activity when compared to the wild-type sequence. Conclusions: The previously identified and presumed pathogenic OVOL2 promoter variant c.-307T>C was identified in the PPCD family that established the PPCD1 locus. However, the failure to identify presumed pathogenic coding or non-coding OVOL2 or ZEB1 variants, or CNV involving the PPCD1 and PPCD3 loci in 26 other PPCD probands suggests that other genetic loci may be involved in the pathogenesis of PPCD.
2017-03-08 | GSE84940 | GEO
Project description:To investigate the molecular basis of posterior polymorphous corneal dystrophy (PPCD) by examining the transcriptome in affected individuals and the effect of decreased ZEB1 expression on corneal endothelial gene expression.
2017-08-17 | GSE90489 | GEO
Project description:Alterations in GRHL2-OVOL2-ZEB1 Axis and Aberrant Activation of Wnt Signaling Lead to Altered Gene Transcription in Posterior Polymorphous Corneal Dystrophy
| PRJNA522067 | ENA
Project description:The zinc finger e-box binding homeobox 1 (ZEB1) transcription factor is a master regulator of the epithelial to mesenchymal transition (EMT), and of the reverse mesenchymal to epithelial transition (MET) processes. ZEB1 plays an integral role in mediating cell state transitions during cell lineage specification, wound healing and disease. EMT/MET are characterized by distinct changes in molecular and cellular phenotype that are generally context-independent. Posterior polymorphous corneal dystrophy (PPCD), associated with ZEB1 insufficiency, provides a new biological context in which to understand and evaluate the classic EMT/MET paradigm. PPCD is characterized by a cadherin-switch and transition to an epithelial-like transcriptomic and cellular phenotype, which we study in a cell-based model of PPCD generated using CRISPR-Cas9-mediated ZEB1 knockout in corneal endothelial cells (CEnCs). Transcriptomic and functional studies support the hypothesis that CEnC undergo an MET-like transition in PPCD, termed endothelial to epithelial transition (EnET), and lead to the conclusion that EnET may be considered a corollary to the classic EMT/MET paradigm.
2019-06-13 | GSE121680 | GEO
Project description:PurposeTo identify the genetic basis of posterior polymorphous corneal dystrophy (PPCD) in families mapped to the PPCD1 locus and in affected individuals without ZEB1 coding region mutations.MethodsThe promoter, 5' UTR, and coding regions of OVOL2 was screened in the PPCD family in which linkage analysis established the PPCD1 locus and in 26 PPCD probands who did not harbor a ZEB1 mutation. Copy number variation (CNV) analysis in the PPCD1 and PPCD3 intervals was performed on DNA samples from eight probands using aCGH. Luciferase reporter assays were performed in human corneal endothelial cells to determine the impact of the identified potentially pathogenic variants on OVOL2 promoter activity.ResultsOVOL2 mutation analysis in the first PPCD1-linked family demonstrated segregation of the c.-307T>C variant with the affected phenotype. In the other 26 probands screened, one heterozygous coding region variant and five promoter region heterozygous variants were identified, though none are likely pathogenic based on allele frequency. Array CGH in the PPCD1 and PPCD3 loci excluded the presence of CNV involving either OVOL2 or ZEB1, respectively. The c.-307T>C variant demonstrated increased promoter activity in corneal endothelial cells when compared to the wild-type sequence as has been demonstrated previously in another cell type.ConclusionsPreviously identified as the cause of PPCD1, the OVOL2 promoter variant c.-307T>C was herein identified in the original family that established the PPCD1 locus. However, the failure to identify presumed pathogenic coding or non-coding OVOL2 or ZEB1 variants, or CNV involving the PPCD1 and PPCD3 loci in 26 other PPCD probands suggests that other genetic loci may be involved in the pathogenesis of PPCD.
| S-EPMC5207508 | biostudies-literature
Project description:In development, embryonic ectoderm differentiates into several lineages including neuroectoderm and surface ectoderm, through the mechanism largely unclear. Here we report that OVOL2 is required for the transcriptional program of corneal epithelium cell(CEC)s, a derivative of surface ectoderm, and it might regulates the differential transcriptional programs between the two lineages. By a functional screening, we identified transcription factors (TFs) maintaining human CECs. OVOL2 was necessary to maintain the transcriptional program in CECs, particularly through repressing expression of mesenchymal genes. OVOL2 combined with several TFs were able to activate the transcriptional program of CECs in fibroblasts, accompanied by induction of chromatin landscape. Moreover, our analysis revealed that neuroectoderm derivatives express some of mesenchymal genes. In fact, OVOL2 alone was able to induce the transcriptional program of CECs in neural progenitor cells (NPCs) through repression of mesenchymal genes as well as activation of epithelial genes. Our data suggest that the difference between the transcriptional programs of surface ectoderm-derivatives and neuroectoderm-derivatives is regulated in part by the reciprocally-repressive mechanism between epithelial and mesenchymal genes that is seen in epithelial-to-mesenchymal transition.
2016-04-11 | GSE79251 | GEO
Project description:PurposeTo determine how nonsense mutations in the transcription factor ZEB1 lead to the development of posterior polymorphous corneal dystrophy type 3 (PPCD3).MethodsWhole-cell extracts were obtained from cultured human corneal epithelial cells (HCEpCs) as a source of ZEB1 protein. DNA-binding assays were performed using the whole-cell extract and oligonucleotide probes consisting of the two conserved E2-box motifs and surrounding nucleotides upstream of COL4A3. ZEB1 and COL4A3 mRNA expression in primary human corneal endothelial cells (HCEnCs) was assayed in both PPCD3 and control corneas by RT-PCR. Immunohistochemistry was used to localize ZEB1 and COL4A3 expression in normal human cornea.ResultsElectromobility shift assays (EMSAs) and competition EMSAs demonstrated binding of protein(s) in the cultured HCEpCs to the E2-box motifs in the probes. The supershift EMSA confirmed that ZEB1, demonstrated to be present in the whole-cell extracts, binds to both the proximal and distal E2-box motifs in the COL4A3 promoter region. Both COL4A3 and ZEB1 are expressed in normal HCEnCs, although in PPCD3, ZEB1 expression is decreased and COL4A3 expression is increased compared with levels of both genes in healthy control corneas.ConclusionsInversely related HCEnC expression levels of ZEB1 and COL4A3 in PPCD3 indicate that ZEB1-mediated alterations in COL4A3 expression are most likely associated with the pathogenesis of this corneal endothelial dystrophy. However, the demonstration of COL4A3 expression in healthy adult primary HCEnCs suggests that PPCD3 is more likely to involve an alteration in the timing and/or degree of COL4A3 expression than to result from the dichotomous change implied by the previously proposed ectopic expression model.
| S-EPMC3292363 | biostudies-literature
Project description:In development, embryonic ectoderm differentiates into several lineages including neuroectoderm and surface ectoderm, through the mechanism largely unclear. Here we report that OVOL2 is required for the transcriptional program of corneal epithelium cell(CEC)s, a derivative of surface ectoderm, and it might regulates the differential transcriptional programs between the two lineages. By a functional screening, we identified transcription factors (TFs) maintaining human CECs. OVOL2 was necessary to maintain the transcriptional program in CECs, particularly through repressing expression of mesenchymal genes. OVOL2 combined with several TFs were able to activate the transcriptional program of CECs in fibroblasts, accompanied by induction of chromatin landscape. Moreover, our analysis revealed that neuroectoderm derivatives express some of mesenchymal genes. In fact, OVOL2 alone was able to induce the transcriptional program of CECs in neural progenitor cells (NPCs) through repression of mesenchymal genes as well as activation of epithelial genes. Our data suggest that the difference between the transcriptional programs of surface ectoderm-derivatives and neuroectoderm-derivatives is regulated in part by the reciprocally-repressive mechanism between epithelial and mesenchymal genes that is seen in epithelial-to-mesenchymal transition.
2016-04-11 | GSE67821 | GEO
Project description:Purpose: To identify the genetic basis of posterior polymorphous corneal dystrophy 1 (PPCD1). Methods: Next-generation sequencing was performed on DNA samples from 4 affected and 4 unaffected members of a previously reported family with PPCD1 linked to chromosome 20 between D20S182 and D20S195. Custom capture probes were utilized for targeted region capture of the linked interval. Single nucleotide variants (SNVs) and insertions/deletions (indels) were identified using two bioinformatics pipelines and two annotation databases. Candidate variants met the following criteria: quality score â¥20, read depth â¥5X, heterozygous, novel or rare (minor allele frequency (MAF) ⤠0.05), present in each affected individual and absent in each unaffected individual. Structural variants were detected with two different microarray platforms to identify indels of varying sizes. Results: Sequencing reads aligned to the linked region on chromosome 20, and high coverage was obtained across the sequenced region. The majority of identified variants were detected with both pipelines and annotation databases, although unique variants were identified. Twelve SNVs in 10 genes (2 synonymous variants and 10 noncoding variants) and 9 indels in 7 genes met the filtering criteria and were considered candidate variants for PPCD1. Conclusions: Next-generation sequencing of the PPCD1 interval has identified 17 genes containing novel or rare SNVs and indels that segregate with the affected phenotype in an affected family previously mapped to the PPCD1 locus. We anticipate that screening of these candidate genes in other families previously mapped to the PPCD1 locus will result in the identification of the genetic basis of PPCD1. Four affected and 4 unaffected individuals from a single family were analyzed for copy number variation within the PPCD1 disease locus. Array design and analysis is based on genome build hg19.
2016-06-30 | E-GEOD-72617 | biostudies-arrayexpress
Project description:Posterior polymorphous corneal dystrophy (PPCD), a rare, bilateral, autosomal-dominant, inherited corneal dystrophy, affects the Descemet membrane and corneal endothelium. We describe an unusual presentation of PPCD associated with a previously unknown genetic alteration in the ZEB1 gene. The proband is a 64-year-old woman diagnosed with keratoconus referred for a corneal endothelium study who presented endothelial lesions in both eyes suggestive of PPCD, corectopia and iridocorneal endothelial synechiae in the right eye and intrastromal segments in the left eye. The endothelial count was 825 in the right eye and 1361 in the left eye, with typical PPCD lesions visible under specular and confocal microscopy. In the next generation sequencing genetic analysis, a heterozygous c.1A > C (p.Met1Leu) mutation was found in the ZEB1 gene (TCF8). The PPCD3 subtype is associated with corneal ectasia, and both can appear due to a pathogenic mutation in the ZEB1 gene (OMIM #189909). However, our patient had a previously unreported mutation in the ZEB1 gene, which mediates the transition between cell lines and provides a pathogenic explanation for the epithelialisation of the corneal endothelium, a characteristic of PPCD.
| S-EPMC9820445 | biostudies-literature