Project description:The purpose of this study is to understand the gene expression profiling, altered pathways and protein networks involved in Aniridia Related Keratopathy. RNA-sequencing was performed on 3 biological replicates of both wildtype PAX6 mice and heterozygous mutant PAX6 corneas.
Project description:PAX6-related Aniridia is a sight-threatening disease due to progression of secondary glaucoma and aniridia associated keratopathy (AAK). Changes or loss of limbal epithelial progenitors causes the epithelial surfaces defects. We analyzed how PAX6 contribute to this with a two-step approach. 1) mRNA Sequencing of limbal epithelial cells isolated from controls and aniridia patients. 2) confirming the bioinformatical and literature-based result list on a siRNA based primary aniridia cell model (PAX6- knockdown). With this approach genes which are directly influenced by PAX6 should be distinguishable from genes secondary affected by AAK disease state. Therefore epithelial cells were isolated from the limbus region of two patients with aniridia and cultured in KSFM medium. Normal cells were obtained from limbus region of cadaveric control patients. For the siRNA based anridia cell model cells were transfected with lipofectamine and 5 nM siRNA against PAX6 or scrambled control. All cells were lysed to obtain DNA, RNA and protein. Reduction of PAX6 protein was controlled by Western Blot. Aniridia and Control Poly-A enriched RNA-librarys were subjected to Next Generation Sequencing. The differential analysis was a combination of quantification with RSEM and differential tests with edgeR. Gene lists were filtered by comparing to NCBI GEO Datasets, annotation with DAVID and manually annotation using literature search. For the resulting filtered gene list qPCR primer were ordered and postulated changes were verified with qPCR on siRNA based aniridia- cell model (Namely: TP63, ABCG2, ADH7, ALDH1A1, PITX1, DKK1, DSG1, K12, K3, K13, SPINK6, SPINK7, CTSV, SPERPINB1). We could identify genes which might be regulated by PAX6. We could show that SPINK7 mRNA coding for a protease inhibitor is downregulated in patients as well as in our primary aniridia cell model. ALDH1A1 and AHD7 mRNAs were reduced in limbal epithelial cells of aniridia patients (AN-LEC). Both transcripts were downregulated upon PAX6 knockdown in our cell model.Our siRNA-based aniridia cell model is a tool to proof identified PAX6 affected genes which might drive AAK pathogenesis. We could demonstrate, that this is the fact for transcripts coding for retinol converting enzymes. This provides evidence that PAX6 might drive corneal epithelial differentiation process by direct or indirect controlling retinoic acid signaling processes.
Project description:Purpose: To evaluate conjunctival cell microRNA and mRNA expression in relation to observed phenotype and genotype of aniridia-associated keratopathy (AAK) in a cohort of subjects with congenital aniridia. Methods: Using impression cytology, bulbar conjunctival cells were sampled from 20 subjects with congenital aniridia and 20 age and sex-matched healthy control subjects. RNA was extracted and microRNA and mRNA analysis was performed using microarrays. Results were related to the presence and severity of AAK determined by a standardized clinical grading scale and to the genotype (PAX6 mutation?) determined by clinical genetics. Results: Of the 2549 microRNAs analyzed, 21 were differentially expressed relative to controls. Among these miR-204-5p, an inhibitor of corneal neovascularization, was downregulated 26.8-fold, while miR-5787 and miR-224-5p were upregulated 2.8 and 2.4-fold relative to controls, respectively. At the mRNA level, 539 transcripts were differentially expressed, among these FOSB and FOS were upregulated 17.5 and 9.7-fold respectively, and JUN by 2.9-fold, all components of the AP-1 transcription factor complex. Pathway analysis revealed dysregulation of several enriched pathways including PI3K-Akt, MAPK, and Ras signaling pathways in aniridia. For several microRNAs and transcripts, expression levels aligned with AAK severity, while in very mild cases with missense or non-PAX6 coding mutations, gene expression was only minimally altered. Conclusion: In aniridia, specific factors and pathways are strongly dysregulated in conjunctival cells, suggesting that the conjunctiva in aniridia is abnormally maintained in a pro-angiogenic and proliferative state, promoting the aggressivity of AAK in a mutation-dependent manner. Transcriptional profiling of conjunctival cells at the microRNA and mRNA levels presents a powerful, minimally-invasive means to assess the regulation of cell dysfunction at the ocular surface.
Project description:Purpose: To evaluate conjunctival cell microRNA and mRNA expression in relation to observed phenotype and genotype of aniridia-associated keratopathy (AAK) in a cohort of subjects with congenital aniridia. Methods: Using impression cytology, bulbar conjunctival cells were sampled from 20 subjects with congenital aniridia and 20 age and sex-matched healthy control subjects. RNA was extracted and microRNA and mRNA analysis was performed using microarrays. Results were related to the presence and severity of AAK determined by a standardized clinical grading scale and to the genotype (PAX6 mutation?) determined by clinical genetics. Results: Of the 2549 microRNAs analyzed, 21 were differentially expressed relative to controls. Among these miR-204-5p, an inhibitor of corneal neovascularization, was downregulated 26.8-fold, while miR-5787 and miR-224-5p were upregulated 2.8 and 2.4-fold relative to controls, respectively. At the mRNA level, 539 transcripts were differentially expressed, among these FOSB and FOS were upregulated 17.5 and 9.7-fold respectively, and JUN by 2.9-fold, all components of the AP-1 transcription factor complex. Pathway analysis revealed dysregulation of several enriched pathways including PI3K-Akt, MAPK, and Ras signaling pathways in aniridia. For several microRNAs and transcripts, expression levels aligned with AAK severity, while in very mild cases with missense or non-PAX6 coding mutations, gene expression was only minimally altered. Conclusion: In aniridia, specific factors and pathways are strongly dysregulated in conjunctival cells, suggesting that the conjunctiva in aniridia is abnormally maintained in a pro-angiogenic and proliferative state, promoting the aggressivity of AAK in a mutation-dependent manner. Transcriptional profiling of conjunctival cells at the microRNA and mRNA levels presents a powerful, minimally-invasive means to assess the regulation of cell dysfunction at the ocular surface.
Project description:Heterozygous PAX6 gene mutations leading to haploinsufficiency are the main cause of congenital aniridia, a rare and progressive panocular disease characterized by reduced visual acuity. Up to 90% of patients suffer from aniridia-related keratopathy (ARK), caused by a combination of factors including limbal epithelial stem-cell (LSC) deficiency, impaired healing response and abnormal differentiation. It usually begins in the first decade of life, resulting in recurrent corneal erosions, sub-epithelial fibrosis and corneal opacification. Unfortunately, there are currently no efficient treatments available for these patients and no in vitro model for this pathology. We used CRISPR/Cas9 technology to introduce into the PAX6 gene of LSCs a heterozygous nonsense mutation found in ARK patients. Nine clones carrying a p.E109X mutation on one allele were obtained with no off-target mutations. Compared to the parental WT-LSCs, heterozygous mutant LSCs displayed reduced expression of PAX6 and marked slow-down of cell proliferation, migration and detachment. Remarkably, addition to the culture medium of recombinant PAX6 protein fused to a cell penetrating peptide was able to activate the endogenous PAX6 gene and to rescue phenotypic defects of mutant LSCs, suggesting that administration of such recombinant PAX6 protein could be a promising therapeutic approach of congenital aniridia. More generally, our results demonstrate that introduction of disease mutations into LSCs by CRISPR/Cas9 genome editing allows creating relevant cellular models of ocular disease that should greatly facilitate screening of novel therapeutic approaches.
Project description:Identification of gene expression signatures and related microRNAs for chronic glomerulonephritis based on microarray and bioinformatic analysis