Abstract
Purpose :
Astrocytes are the major glia cell type within the optic nerve head (ONH). During glaucoma pathogenesis, elevated intraocular pressure (IOP) deforms the ONH and activates astrocytes relevant to their mechanosensing mechanisms. In this study, we performed RNA sequencing (RNA-seq) to investigate the mechanisms underlying astrocyte activation.
Methods :
Primary mouse ONH astrocytes were derived from C57BL/6J mice and subjected to mechanical stretch of 12% strain for 24 hours using a FlexCell Tension System. Total RNA was extracted from astrocytes and RNA-seq libraries were prepared and sequenced on an Illumina Miseq2000. RNA-seq analysis was performed to identify significant differentially expressed genes, which were further investigated in pathway enrichment analysis. The Egl1 mouse strain was obtained from the Jackson Laboratory and intraocular pressure (IOP) was measured non-invasively using the TonoLab tonometer. Immunofluorescent staining was performed to validate the gene of interest in the ONH of glaucomatous mice.
Results :
RNA-seq identified 2197 significantly up-regulated and 2092 significantly down-regulated genes (FDR<0.05) in mechanically stretched ONH astrocytes. Based on gene ontology enrichment results, identified genes are associated with a variety of cellular components (pigment granule, preribosome, et al.), biological processes (ATP hydrolysis coupled cation transmembrane transport, protein folding, et al.) and molecular functions (structural constituent of cytoskeleton, tRNA binding, et al.). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis show that differentially regulated genes are involved in phagosome, carbon metabolism, and Aminoacyl-tRNA biosynthesis, et al. There was an increased expression of Iba1 in the ONH of glaucomatous mice.
Conclusions :
Mechanical stretch regulates the expression levels of genes that may be responsible for ONH astrocyte activation during the pathogenesis of glaucoma. This study provides new insights into mechanisms of astrocyte activation induced by mechanical stimulation. These new insights will lead to novel therapeutic targets for glaucoma.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.