Astaxanthin mediated regulation of VEGF through HIF1 α and XBP1 signaling pathway: An insight from ARPE-19 cell and streptozotocin mediated diabetic rat model

Exp Eye Res. 2021 Mar 28:108555. doi: 10.1016/j.exer.2021.108555. Online ahead of print.ABSTRACTBreakdown of outer blood-retina barrier (BRB) has been associated with the pathogenesis of diabetic retinopathy (DR) and diabetic macular edema (DME). Vascular endothelial growth factor (VEGF) might play a detrimental role in the pathogenesis of DME, a major clinical manifestation of DR. In the present study, we investigated the inhibitory mechanism of astaxanthin on VEGF and its upstream signaling pathways under in vitro and in vivo conditions. Astaxanthin has been observed to downregulate VEGF expression under hyperglycemic (HG) and CoCl2 induced hypoxic conditions in ARPE-19 cells. There were compelling pieces of evidence for the involvement of transcription factors like HIF1α and XBP1 in the upregulation of VEGF under HG and hypoxic conditions. Thus, we investigated the role of astaxanthin in the expression and nuclear translocation of HIF1α and XBP1. The activation and translocation of HIF1α and XBP1 induced by HG or CoCl2 conditions were hindered by astaxanthin. Additionally, treatment with HIF1α siRNA and IRE1 inhibitor STF-083010 also inhibited the expression of VEGF induced by HG and CoCl2 conditions. These results indicated that the anti-VEGF property of astaxanthin might be associated with the downregulation of HIF1α and XBP1. Furthermore, astaxanthin mitigated the enhanced migration of retinal pigment epithelial (RPE) cells under DR conditions. As well, astaxanthin...
Source: Experimental Eye Research - Category: Opthalmology Authors: Source Type: research