Abstract
Purpose :
Intraocular pressure (IOP) elevation is a major risk factor causing insidious vision deterioration in primary open angle glaucoma in which inflammation and apoptosis lead to optic nerve damage and retinal ganglion cell (RGC) loss. Pre-clinical studies showed that adeno-associated virus (AAV)-mediated transfer of SIRT1, a NAD+-dependent deacetylase with anti-oxidative stress and anti-inflammatory functions, promotes effective neuroprotection following injury. Herein, we used a mouse model of chronic ocular hypertension to examine the molecular bases of AAV-SIRT1-based gene therapy.
Methods :
Eight-week old C57BL[RA1] /6 mice (3 animals/group) were intravitreally injected with either control or therapeutic AAV expressing a g-synuclein promoter-driven human SIRT1 cDNA (AAV-SIRT1). Two weeks later, IOP was elevated in mice through intracameral injection of magnetic microbeads. RNA sequencing and pathway enrichment analyses were performed to determine transcriptomic changes among retinas from control and high IOP mice with and without AAV-SIRT1 treatments for 2 and 8 weeks after the onset of elevated IOP.
Results :
IOP elevation induced differential expression of 165 genes, of which 151 were upregulated and 14 were downregulated after 2 weeks. The expression of 57 genes remained elevated after 8 weeks of IOP elevation. More than 29 biological processes and molecular functions were affected by IOP elevation with most genes being associated with inflammation, adaptive and innate immune responses, cellular transport, and angiogenesis. AAV-SIRT1-treatment affected the expression of 67 genes. Of these, Gja3 and -8, Birc7, Mip, Sox1ot, Wnt7a- and -b, Serpind1 and Fgfr3 were the most downregulated and Serpine3 and Lad1 were the most upregulated genes in mice with elevated IOP for 2 weeks. At 8 weeks of IOP elevation, AAV-SIRT1 therapy upregulated the expression of CD200r4, Igvh3-6 and IL7r, which regulate neuroinflammation, phagocytosis. and immune response, respectively. Additionally, identifiers (e.g., GAP43, WSCD2, SNCG) and neuronal survival factors (e.g., NRTN) of RGCs were selectively enriched in the transcriptome of AAV-SIRT1-treated mouse retinas.
Conclusions :
Results suggest that SIRT1-treatment enhances the survival potential of RGCs, as marked by preserved expression of several RGC subtype markers and may work, at least in part, by mitigating inflammatory responses.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.