Abstract
Purpose :
Cellular senescence is a hallmark of aging. Progressive deterioration of ocular neurovascular functions is exacerbated by aging in glaucoma. We recently unraveled the crucial role of the cytochrome P450 (CYP) pathway in the retina (R) and ophthalmic artery (OA). The CYP metabolites are hydrolyzed by soluble epoxide hydrolase (sEH), which diminishes their protective effects. Hence, sEH has emerged as a novel inhibitory drug target. This study deciphered the molecular implications of Ephx2 gene knockout (KO) that impinge senescence in the R and OA.
Methods :
Retinae and OA were isolated from 80 young (3-5 months) and old (12-24 months) male wild type (WT) and KO mice. Samples were pooled (n=5 mice/group/replicate) with 4 biological replicates/group and subjected to mass spectrometry-based proteomics to profile the differentially expressed proteins (DEP) and in-silico bioinformatics analyses to elucidate cell signaling changes.
Results :
Aging significantly (p<0.05) altered the proteome of both R and OA of WT mice, with 183 and 111 DEP, respectively. Remarkably, KO profoundly decreased the DEP in the aging R and OA to 155 and 57 proteins, respectively. In the OA, KO significantly ameliorated inflammatory response in young (p=2.63×10-6) and aged (p=7.39×10-5) mice. Aging-related apoptotic and oxidative stress proteins in WT were also significantly mitigated in the KO, while vascular protective mechanisms driven by the RhoA-RhoGDI-eNOS signaling proteins vital for reversing aging-induced dysfunction was highly regulated. In the R, KO influenced protein translation dynamics mediated by the eIF2 signaling (p=1.15×10-12) as a stress response to restore cellular homeostasis in the aging mice, supported by significant activation of a translation regulator that regulates protein synthesis, LARP1, in the aged KO (p=10×10-16) compared to aged WT (p= 3.1×10-5). Importantly, KO significantly reprogrammed R protein expression involved in bioenergetics via oxidative phosphorylation (p=1.3×10-6) and inhibition of mitochondrial dysfunction (p=3.4×10-3) in young mice, with corresponding involvement of UQCC3 (p=7.3×10-7).
Conclusions :
We demonstrated for the first time that Ephx2 gene deletion significantly reprogrammed detrimental senescesome in ocular neurovascular tissues. The potential use of sEH inhibitors in aging glaucoma patients needs further investigation.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.