Autophagy modulation in organotypic retinal cultures exposed to high glucose

Abstract

Purpose: Diabetic retinopathy (DR) is one of the most serious complications of diabetes mellitus and a leading cause of vision loss among working‐age population in industrialized countries (1, 2). DR has long been considered a microvascular disease (3). However, more recently, neurodegeneration and neuroinflammation emerged as important determinants in the pathogenesis and evolution of the pathology (4). Autophagy, the main catabolic pathway involved in the degradation and recycling of damaged organelles and macromolecules, plays an important role in the pathophysiology of retina neurodegenerative diseases (5). Here we studied the changes occurring in ex‐vivo cultured retinas under normal and high glucose conditions and focused on the autophagy pathway. Methods: Organotypic retinal culture from C57BL/6J mice were exposed to normal (15 mM) (NG) or high (50 mM) glucose (HG) for 7 days. Neuronal survival and glial activation were studied by immunofluorescence with cell subtype specific antibodies. Protein or mRNA levels of autophagy‐related proteins (LC3, p62, Atg5‐12) and inflammatory markers (GFAP, IL‐1β and IL‐6) were studied by western blotting or quantitative PCR. Results: Loss of the neuronal components and reduction of glial reactivity were observed in the retina maintained in NG for 7 days. These cellular changes were only slightly affected by exposure to HG. However, under these conditions an upregulation of inflammatory related proteins and significant changes in the autophagic flux were reported. Conclusions: Our preliminary data suggest that autophagy is modulated in organotypic retinal cultures exposed to HG although further experiments are needed to define its pathological role. References. 1. Seewoodhary M. Nurs Stand(2021; 30 36: 71–76. 2. Prokofyeva E and Zrenner E. Ophthalmic Res 2012; 7 47: 171–188. 3. Cheung CY et al. Diabetologia 2017; 60: 1770–1781. 4. Kadłubowska J et al. Curr Neuropharmacol 2016; 14: 831–839. 5. Adornetto A et al. Front Cell Dev Biol 2020; 4;8: 121. This work is supported by grants from the Italian Ministry of Education, University and Research: PRIN 2017 protocol number “2017TSHBXZ_002.”