Rapamycin and Resveratrol Modulate the Gliotic and Pro-Angiogenic Response in Müller Glial Cells Under Hypoxia

SUBIRADA, PAULA V.; VAGLIENTI, MARÍA V.; JORAY, MARIANA B.; PAZ, MARÍA C.; BARCELONA, PABLO F.; SÁNCHEZ, MARÍA C.

Frontiers in Cell and Developmental Biology

Frontiers Media S.A.

Año: 2022 vol. 10

Hypoxia and hypoxia-reoxygenation are frequently developed through the course of manyretinal diseases of different etiologies. Müller glial cells (MGCs), together with microglia andastrocytes, participate firstly in response to the injury and later in the repair of tissuedamage. New pharmacological strategies tend to modulate MGCs ability to induceangiogenesis and gliosis in order to accelerate the recovery stage. In this article, weinvestigated the variation in autophagy flux under hypoxia during 4 h, employing both gasculture chamber (1% O2) and chemical (CoCl2) hypoxia, and also in hypoxiareoxygenation. Then, we delineated a strategy to induce autophagy with Rapamycinand Resveratrol and analysed the gliotic and pro-angiogenic response of MGCs underhypoxic conditions. Our results showed an increase in LC3B II and p62 protein levels afterboth hypoxic exposure respect to normoxia. Moreover, 1 h of reoxygenation after gashypoxia upregulated LC3B II levels respect to hypoxia although a decreased cell survivalwas observed. Exposure to low oxygen levels increased the protein expression of the glialfibrillary acid protein (GFAP) in MGCs, whereas Vimentin levels remained constant. In ourexperimental conditions, Rapamycin but not Resveratrol decreased GFAP protein levels inhypoxia. Finally, supernatants of MGCs incubated in hypoxic conditions and in presence ofthe autophagy inductors inhibited endothelial cells (ECs) tubulogenesis. In agreement withthese results, reduced expression of vascular endothelial growth factor (VEGF) mRNA wasobserved in MGCs with Rapamycin, whereas pigment epithelium-derived factor (PEDF)mRNA levels significantly increased in MGCs incubated with Resveratrol. In conclusion,this research provides evidence about the variation of autophagy flux under hypoxia andhypoxia-reoxygenation as a protective mechanism activated in response to the injury. Inaddition, beneficial effects were observed with Rapamycin treatment as it decreased thegliotic response and prevented the development of newly formed blood vessels.