Cell signaling pathways in human mutant PAX6 corneal cells: an in vitro model for aniridia-related keratopathy

PURPOSETo establish an in vitro model of aniridia-related keratopathy (ARK) using CRISPR/Cas9 engineered human keratocytes with mutations in the PAX6 gene, and to study the Notch Homolog 1, Translocation-Associated (Notch1), sonic hedgehog (SHH), mammalian target of rapamycin (mTOR), and Wnt/{beta}-catenin signaling pathways in the PAX6 mutant keratocytes. METHODSPrimary human keratocytes were isolated from healthy corneas. Keratocytes were transduced with Cas9 lentiviral particles in order to create cells stably expressing Cas9 nuclease. Lentiviral particles carrying PAX6 sgRNA were transduced into the Cas9 keratocytes creating mutants. Analysis of signaling pathways was assessed by RT-qPCR for gene expression and western blot for protein expression. RESULTSHuman keratocytes stably expressing Cas9 nuclease were created. Keratocytes carrying PAX6 gene mutation were successfully generated. PAX6 mutant keratocytes showed modified expression patterns of extracellular matrix components such as collagens and fibrotic markers. Analysis of the Notch1, SHH, mTOR, and Wnt/{beta}-catenin signaling pathways in the PAX6 mutant keratocytes revealed altered gene and protein expression of the key players involved in these pathways. CONCLUSIONSA properly functioning PAX6 gene in keratocytes is crucial for the regulation of signaling pathways important for cell fate determination, proliferation, and inflammation. Pax6 mutation in the in vitro settings leads to changes in these pathways which resemble those found in corneas of patients with ARK.