Bone Marrow Mesenchymal Stem Cell Exosomal miR-345-3p Ameliorates Cerebral Ischemia-reperfusion Injury by Targeting TRAF6.

Introduction: The purpose of this study was to investigate the effects of bone marrow mesenchymal stem cells (BMSCs) exosomal miR-345-3p and tumor necrosis factor receptorassociated factor 6 (TRAF6) on cerebral ischemia reperfusion (CIR) injury. Exosomes (Exos) derived from BMSCs were isolated and identified. PC12 (rat pheochromocytoma) cells were used to establish an oxygen and glucose deprivation/reoxygenation (OGD/R) model.

Methods: Cell counting kit-8, TUNEL staining, lactate dehydrogenase staining, RT-qPCR, and western blotting were utilized for analyzing the functions of miR-345-3p about PC12 cells. Dualluciferase reporter experiment was then to confirm the link between miR-345-3p and TRAF6. Finally, using male SD rats, the middle cerebral artery occlusion (MCAO) model was constructed. Regulation of I/R damage in MCAO rats of miR-345-3p and TRAF6 were further explored in the changes of modified neurological severity score, cerebral infarction pictures, relative infarct volume, and histopathological changes. After OGD/R treatment, neuronal apoptosis was dramatically increased. After treatment with exosomal miR-345-3p, OGD/R-induced neuroapoptosis was dramatically inhibited. Exosomal miR-345-3p inhibited OGD/R-induced neuroapoptosis by downregulating the expression of TRAF6. However, the miR-345-3p inhibitor aggravated the changes caused by OGD/R.

Results: The corresponding regulations of miR-345-3p were reversed with TRAF6 overexpression. The animal experiments in vivo further verified that miR-345-3p ameliorated brain I/R injury in MCAO rats by targeting TRAF6.

Conclusion: This study found that BMSCs-exosomal miR-345-3p protected against CIR injury by decreasing TRAF6.