IMPAIRED AUTOPHAGY FLUX IN MÜLLER GLIAL CELLS EXPOSED TO HYPOXIA: IN VITRO AND IN VIVO MODELS

SUBIRADA, PV; BARCELONA, PF; PAZ, MC; SANCHE, MC; RIDANO, ME; FADER KAISER C

CORDOBA

Congreso; SAIB 2016 (XLVII Reunión Anual de Sociedad Argentina en Bioquímica y Biología Molecular); 2016

Sociedad de Bioquimica y Biologia Molecular

Hypoxia is one of the main insults in Diabetic Retinopathy (DR) and Retinopathy of Prematurity (ROP), leading to neovascularization and neurodegeneration. In this pathological context, Müller Glial Cells (MGCs) has been reported to participate in retinal homeostasis maintenance by eliminating protein aggregates, activating stress proteins and detoxifying mechanisms. Here, we investigate whether autophagy is involved in MGCs response under hypoxia. MIO- M1, a human immortalized cell line of MGCs, were pre incubated with cloroquine 10 uM and exposed to CoCl2 250 uM for 24 h. In a similar experiment, MIO-M1 were exposed to 0,1% O2. Western blot and immunofluorescence analysis revealed increased levels of LC3B-II and p62/SQTSM1 but decreased colocalization of LC3 and lysotracker. In addition, autophagy flux was determined in the OIR mice model, which closely resemble ROP and DR. C57/BL6 mice exposed to 75% O2 from postnatal day (P)7 to 12, were brought to room air (RA) for additional five (P17) or nine days (P26). Age-matched mice maintained in RA were used as control. Western blot of neural retinas showed changes in autophagy flux, glutamine syntethase, total caspase 3 and GFAP levels at p12, p17 and p26. A distinct pattern of LC3 was observed at the end feet of MGCs by immunofluorescence staining demostrating that hypoxia modifies autophagy flux in MGCs during retinopathies.