Abstract
Purpose :
Heme oxygenase-1(HO-1) is a novel enzyme with potent anti-oxidant and anti-proliferative effects. The expression of HO-1 via Nrf2/HIFF-1α pathway has been shown to play a key role in diabetic retinopathy. This research aims to investigate the protective effects of pharmacological induced HO-1，expressed by primary cultured Müller cells, in human vascular endothelial cells and explore the potential mechanism.
Methods :
We identified Heme/ZnPP-IX as inducer/inhibitor of heme oxygenase-1(HO-1) in primary cultured Sprague-Dawley (SD) rats’ Müller cells in vitro. 50mM high glucose /72 hour is the stress state which decreased the expression of HO-1. HO-1, Nrf2, HIF-1α,VEGF, SOD-1 and bcl-2 protein and mRNA expression were detected using immunohistochemical and biochemical methods. The expression of HO-1, Nrf-2, HIF-1α, SOD-1 and bcl-2 were confirmed by immunohistochemistry in Müller cells cultured by DMEM contained high and normal concentrations of glucose. Human vascular endothelial cells were co-cultured with Müller cells pretreated by heme and ZnPP-IX and the expression of VEGF were detected.
Results :
Heme/ZnPP-IX significantly increased/blocked HO-1 expression combined with accordant changes of Nrf2 gene and HIF-1α expression and further down-regulated the expression of VEGF in vascular endothelial cells. Retinal ganglion cells displayed greater sensitivity to apoptosis when HO-1 expression was inhibited. Concurrently, the induced overexpression of HO-1 was associated with an increase in the activation of SOD-1,bcl-2 in Müller cells.
Conclusions :
HO-1 is an important positive modulator that counteracts diabetic-retinopathy-mediated injuries in Müller cells and vascular endothelial cells and enhancement of the HO-1 expression has a potential therapeutic strategy. The Nrf2/HIF-1α signaling pathway may has certain correlation.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.