RESULTS: We show that miR-15a is increased in the plasma of diabetic patients, correlating with disease severity. miR-15 plays an important role in insulin production in pancreatic β-cells. By culturing rat pancreatic β-cells (INS-1) cells in high-glucose media, we identified a source of increased miR-15a in the blood as exosomes secreted by pancreatic β-cells. We postulate that miR-15a, produced in pancreatic β-cells, can enter the bloodstream and contribute to retinal injury. miR-15a overexpression in Müller cells can be induced by exposing Müller cells to exosomes derived from INS-1 cells under high-glucose conditions and results in oxidative stress by targeting Akt3, which leads to apoptotic cell death. The in vivo relevance of these findings is supported by results from high-fat diet and pancreatic β-cell-specific miR-15a-/- mice.
INNOVATION: This study highlights an important and underappreciated mechanism of remote cell-cell communication (exosomal transfer of miRNA) and its influence on the development of T2D complications.
CONCLUSION: Our findings suggest that circulating miR-15a contributes to the pathogenesis of diabetes and supports the concept that miRNAs released by one cell type can travel through the circulation and play a role in disease progression via their transfer to different cell types, inducing oxidative stress and cell injury. Antioxid. Redox Signal. 27, 913-930.
METHOD: In this study, we investigated the effects of methanol neurotoxicity on memory function and pathological outcomes in the hippocampus of adolescent rats and examined the efficacy of Light- Emitting Diode (LED) therapy. Methanol induced neurotoxic rats showed a significant decrease in the latency period, in comparison to controls, which was significantly improved in LED treated rats at 7, 14 and 28 days, indicating recovery of memory function. In addition, methanol neurotoxicity in hippocampus caused a significant increase in cell death (caspase3+ cells) and cell edema at 7 and 28 days, which were significantly decreased by LED therapy. Furthermore, the number of glial fibrillary acid protein astrocytes was significantly lower in methanol rats, compared to controls, whereas LED treatment caused their significant increase. Finally, methanol neurotoxicity caused a significant decrease in the number of brain-derived neurotrophic factor (BDNF+) cells, but also circulating serum BDNF, at 7 and 28 days, compared to controls, which were significantly increased by LED therapy. Importantly, LED significantly increased the number of Ki-67+ cells and BDNF levels in the serum and hypothalamus in control-LED rats, compared to controls without LED therapy.
CONCLUSION: In conclusion, chronic methanol administration caused severe memory impairments and several pathological outcomes in the hippocampus of adolescent rats which were improved by LED therapy.