Involvement Of Sirt3-Gsk3 Beta Deacetylation Pathway In The Effects Of Maternal Diabetes On Oocyte Meiosis

Objectives It has been widely reported that maternal diabetes impairs oocyte quality. However, the responsible mechanisms remain to be explored. In the present study, we focused on whether SIRT3-GSK3 beta pathway mediates the meiotic defects in oocytes from diabetic mice.Materials and methods GSK3 beta functions in mouse oocyte meiosis were first detected by targeted siRNA knockdown. Spindle assembly and chromosome alignment were visualized by immunostaining and analysed under the confocal microscope. PCR-based site mutation of specific GSK3 beta lysine residues was used to confirm which lysine residues function in oocyte meiosis. siRNA knockdown coupled with cRNA overexpression was performed to detect SIRT3-GSK3 beta pathway functions in oocyte meiosis. Immunofluorescence was performed to detect ROS levels. T1DM mouse models were induced by a single intraperitoneal injection of streptozotocin.Results In the present study, we found that specific depletion of GSK3 beta disrupts maturational progression and meiotic apparatus in mouse oocytes. By constructing site-specific mutants, we further revealed that acetylation state of lysine (K) 15 on GSK3 beta is essential for spindle assembly and chromosome alignment during oocyte meiosis. Moreover, non-acetylation-mimetic mutant GSK3 beta-K15R is capable of partly preventing the spindle/chromosome anomalies in oocytes with SIRT3 knockdown. A significant reduction in SIRT3 protein was detected in oocytes from diabetic mice. Of note, forced expression of GSK3 beta-K15R ameliorates maternal diabetes-associated meiotic defects in mouse oocytes, with no evident effects on oxidative stress.Conclusion Our data identify GSK3 beta as a cytoskeletal regulator that is required for the assembly of meiotic apparatus, and discover a beneficial effect of SIRT3-dependent GSK3 beta deacetylation on oocyte quality from diabetic mice.