Gene expression study in the siRNA based aniridia cell model and in primary aniridia limbal epithelial cells following duloxetine and ritanserin treatment.

Progressive aniridia associated keratopathy is worsening visual acuity of congenital aniridia subjects lifelong. Restoration of PAX6 expression in PAX6 haploinsufficient limbal epithelial cells could be one therapeutic option. In a previous study using aniridia-like CRISPR/Cas9 genome-edited corneal epithelial cells, the antipsychotic drugs duloxetine and ritanserin increased PAX6 mRNA and protein expression. Our purpose was to investigate the effect of duloxetine and ritanserin on cultured primary limbal epithelial cells (pLECs) without and with PAX6 knockdown. pLECs were isolated from 11 aniridia patients and corneoscleral rims of 8 healthy human donors and were treated with 5 µM duloxetine or ritanserin for 24 hours. In addition, pLECs were transfected with small interfering RNA (siRNA) (PAX6 knockdown) in the siRNA-based aniridia cell model and were also treated by 5 µM duloxetine or ritanserin for 24 hours. Gene and protein expression were analyzed using qPCR and Western blot. In both primary aniridia limbal epithelial cells and the siRNA-based aniridia cell model, the expression of PAX6 at the transcriptional or translational level did not show significant changes through duloxetine or ritanserin treatment (p > 0.5). The target genes of PAX6 such as KRT3, KRT12, DSG1, ALDH1A1, ADH7, FABP5, ABCG2 also did not change significantly (p ≥ 0.2). Our study shows that primary cultures of limbal epithelial cells from both aniridia patients and healthy donors were unresponsive to drug treatment. Therefore, our data suggest that different aniridia cell models or cell culture conditions exhibit varying responses to duloxetine and ritanserin. The use of in vivo models could further enhance our understanding of duloxetine and ritanserin treatment in aniridia-associated keratopathy.