Protective effect of NO2-OA on the oxidative stress, gliosis and pro-angiogenic response in Müller Glial Cells

VAGLIENTI, MARIA V.; SUBIRADA, PAULA V.; JORAY, B.; BARCELONA, PABLO F.; BONACCI, GUSTAVO; SÁNCHEZ, MARÍA C.

Buenos Aires

Congreso; Primer encuentro del club de la glía cono sur; 2022

club de la glía cono sur

Inflammation, oxidative and nitrosative stress participate in the pathogenesis and progression of proliferative retinopathies (PR), which also involves a deregulated neovascularization, with a dramatic increase of vascular endothelial growth factor (VEGF) in the retinal tissue. Vascular changes result in alterations of retinal blood barrier, allowing the extravasation of α2-macroglobulin (α2M), which induce gliosis in Müller Glial cells (MGCs) by the increase of GFAP levels. Nitro-fatty acids (NO2-FA) are important electrophilic signaling mediators with anti-inflammatory and cytoprotective properties (Keap1/Nrf2 pathway). Our goal was to determine the effect of nitro-oleic acid (NO2-OA) on oxidative stress, gliosis and pro-angiogenic response in the human MGC line (MIO-M1). Pure synthetic NO2-OA induced HO-1 protein expression in a time- and concentration-dependent manner in MIO-M1 cells and this up-regulation was abrogated with the Nrf2 pharmacological inhibitor, trigonelline. To determine whether NO2-OA could be beneficial against oxidative stress, we pre-treated MIO-M1 cells with or without NO2-OA before PMA and LPS stimulus. Both, PMA and LPS significantly increased ROS in MIO-M1 cells compared with control and NO2-OA prevented the increase in ROS levels induced by both stimuli. On the other hand, α2M induced gliosis characterized by a significant increase of GFAP and vimentin protein expression. In addition, α2M also increased ROS levels and the pre-treatment with NO2-OA reduced α2M induction of GFAP and ROS to the control level. Finally, to evaluate whether NO2-OA could modulate the proangiogenic response of MIO-M1 cells under hypoxic and proinflammatory conditions, we determined VEGF transcriptional expression by qRT-PCR. NO2-OA did not affect VEGF mRNA expression under hypoxic conditions, but in pro-inflammatory conditions NO2-OA significantly reduced VEGF-A mRNA levels in MIO-M1 cells. Furthermore, NO2-OA inhibited endothelial cells tubulogenesis. Collectively, these results indicate that NO2-OA may act as an antioxidant protecting MIO-M1 cells from oxidative damage, gliosis and the exacerbated proangiogenic response.