206 The Role of Mechanosensitive Ion Channels in Primary Open Angle Glaucoma

Abstract

OBJECTIVES/GOALS: Intraocular pressure is the most significant risk factor for glaucoma. Mechanosensitive proteins may have a critical role in transducing mechanical stimuli that ultimately lead to death of retinal ganglion cells. Our goal is to use genetic and functional approaches to discover mechanosensitive ion channels that mediate the progression of glaucoma. METHODS/STUDY POPULATION: Association data, obtained using a logistic regression model that included age, gender and population substructure as co-variates, for 2,576 SNPs located in the PIEZO1 and PIEZO2 genomic regions were extracted from the NEIGHBORHOOD genome-wide association study results for primary open angle glaucoma (POAG) (3,853 cases and 33,480 controls) and the subset of cases with intraocular pressure (IOP) measurements > 21mmHg (high-tension, HTG) (1868 cases and 33,480 controls). Rare coding PIEZO1 and PIEZO2 variants were evaluated using logistic regression and SNP data from the Human Exome array in 2606 POAG cases and 2606 controls and the subset of 1868 HTG cases and 2606 controls. Immunohistochemistry was used to characterize the expression of Piezo1 and Piezo2 in mouse eye sections. RESULTS/ANTICIPATED RESULTS: Exome data analysis identified two protein-altering variants associated with lower glaucoma risk (P<0.05): a PIEZO1 missense allele (Arg1527His; OR= 0.18, P= 0.001) and a variant disrupting a splice donor site (c.1107+1G>C; OR=0.38, P= 0.02), that prematurely truncates the protein. Investigation of the NEIGHBORHOOD GWAS dataset identified nominal association with common PIEZO2 variants (minor allele frequency > 0.3) in POAG overall (top SNP rs264179, P= 0.008) and in the HTG subgroup (top SNP rs264160, P= 0.001). The associated PIEZO2 SNPs are significantly associated with gene expression in lymphocytes (P< 1x10-8) with the risk allele correlated with decreased gene expression. Piezo1 and Piezo2 are expressed in many ocular tissues in the mouse, including cornea, ciliary body and retina. DISCUSSION/SIGNIFICANCE: We identify rare, protein-altering PIEZO1 variants associated with lower glaucoma risk and show that Piezo1 and Piezo2 are broadly expressed in the eye. Common variants influencing PIEZO2 expression also show nominal association with POAG risk. Inhibition of Piezo1 or augmentation of Piezo2 could be novel therapeutic strategies for glaucoma.