E2f1 mediates high glucose-induced neuronal death in cultured mouse retinal explants

Abstract

Diabetic retinopathy (DR) is the most common complication of diabetes and remains one of the major causes of blindness in the world; infants born to diabetic mothers have higher risk of developing retinopathy of prematurity (ROP). While hyperglycemia is a major risk factor, the molecular and cellular mechanisms underlying DR and diabetic ROP are poorly understood. To explore the consequences of retinal cells under high glucose, we cultured wild type or E2f1 mouse retinal explants from postnatal day 8 with normal glucose, high osmotic or high glucose media. Explants were also incubated with cobalt chloride (CoCl) to mimic the hypoxic condition. We showed that, at 7 days post exposure to high glucose, retinal explants displayed elevated cell death, ectopic cell division and intact retinal vascular plexus. Cell death mainly occurred in excitatory neurons, such as ganglion and bipolar cells, which were also ectopically dividing. Many Müller glial cells reentered the cell cycle; some had irregular morphology or migrated to other layers. High glucose inhibited the hyperoxia-induced blood vessel regression of retinal explants. Moreover, inactivation of E2f1 rescued high glucose-induced ectopic division and cell death of retinal neurons, but not ectopic cell division of Müller glial cells and vascular phenotypes. This suggests that high glucose has direct but distinct effects on retinal neurons, glial cells and blood vessels, and that E2f1 mediates its effects on retinal neurons. These findings shed new light onto mechanisms of DR and the fetal retinal abnormalities associated with maternal diabetes, and suggest possible new therapeutic strategies.

Rb is required for retinal angiogenesis and lamination

“…Our work exposes new roles for Rb in the developing retina, pinpointing aberrant E2f1 and Bax activity as key drivers of defects in neuronal survival and angiogenesis, and further implicating E2f1 in aberrant lamination. The Rb/E2f pathway is commonly involved in many diseases, such as most human cancers 13 , retinal degeneration 51 , diabetic retinopathy 52 , and neuronal degeneration 53 . Abnormal cell survival, proliferation, angiogenesis, and lamination are common features of these diseases.…”

Rb1/Rbl1/Vhl loss induces mouse subretinal angiomatous proliferation and hemangioblastoma

“…Ex vivo retinal explant cultures and ChIP. Retinal explants obtained from P8 WT C57/BL mice were cultured using a modified protocol from previously described methods (73,74). Briefly, both eyes were enucleated and retinas were carefully peeled away from the RPE, and radial cuts were made to flatten the retina.…”

Hyperglycemia induced testicular damage in type 2 diabetes mellitus rats exhibiting microcirculation impairments associated with vascular endothelial growth factor decreased via PI3K/Akt pathway

“…Briefly, RTSCs were transfer into 96-well plate (approximately 5000 cells/well), and were further incubated for 24 hours 37°C. After replacement with fresh medium, VEGF-A (25ng/ml) [ 64 ], CoCl 2 (200 μm/L) [ 65 ], VEGF and CoCl 2 were added to each well respectively for another 2 days, 3days and 4 days. Cells were then incubated for an additional 2 h with CCK-8 reagent (100 μL/mL medium) and read at 450 nm using a microplate reader (Thermo, Varioskan Flash).…”