Abstract
Purpose :
HTRA1 is one of the most significant susceptibility genes in age-related macular degeneration (AMD), and RPE senescence is an important contributor to AMD. But the correlation between HTRA1 and retinal pigment epithelium (RPE) senescence hasn’t been investigated in the pathogenesis of AMD. We hypothesize that HTRA1 could induce RPE senescence in retinal degeneration by activating HIF-1 signaling.
Methods :
C57BL/6J (N=81) and hHTRA1-transgenic mice (hHTRA1-Tg) (N=61) aged 6 to 10 weeks were intraperitoneally injected with 20 mg/kg NaIO3. 10mg/kg KC7F2 was treated 3 days before and 3 days after NaIO3 treatment to inhibit HIF1α translation. Retinal degeneration was detected by fundus photography, fundus fluorescein angiography (FFA) and optical coherence tomography (OCT). Electroretinogram (ERG) was used to evaluate retinal functions. Mitochondria and senescence in RPE of mice were detected by transmission electron microscopy (TEM) and senescence-associated-β-galactosidase (SA-β-gal) staining. Mitochondrial respiration and glycolytic capacity in ARPE-19 cells were measured using oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). 10μM KC7F2 treated for 72h was used to reduce the HIF1α expression in ARPE-19 cells. Student's t-test, one-way ANOVA and Chi-square test were used for statistical analysis.
Results :
81.97% hHTRA1-Tg and 59.26% wild type (WT) mice developed oxidative stress-induced retinal degeneration (p=0.004), and the amplitude of scotopic ERG a-wave of hHTRA1-Tg declined (-14.96±3.30μV) compared to WT (-24.65±2.70μV, p=0.038). RPE senescence was facilitated in hHTRA1-Tg mice. Overexpression of HTRA1 in ARPE-19 cells accelerated cellular senescence. HTRA1 overexpression in ARPE-19 cells impaired mitochondrial function and augmented glycolytic capacity. Upregulation of HTRA1 remarkably activated HIF-1 signaling, shown as promoting HIF1α expression and translocation to the nucleus. KC7F2 significantly prevented HTRA1-induced cellular senescence in ARPE-19 cells and improved the visual function in hHTRA1-Tg mice treated with NaIO3.
Conclusions :
Our study showed elevated HTRA1 contributes to the pathogenesis of AMD by promoting cellular senescence in RPE through damaging mitochondrial function and activating HIF-1 signaling. Inhibition of HIF-1 signaling might serve as a potential therapeutic strategy for AMD.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.