Bridge Integrator 2, a New Specific Target for Improving Reproductive Life Span through RPS6 and NNT

Abstract Female ovary is the earliest degenerated organ and it faces distinct medical disadvantages that impair primordial follicle reserve and oocyte quality. Herein, we found that bridge integrator 2 (Bin2) was predominant within mouse ovaries and oocytes, and global-knockout of Bin2 improved both female fertility and oocyte quality with healthy physiology in mice. Ovarian quantitative proteomics and phosphomics showed that Bin2 knockout specifically decreased only p-RPS6 of mTOR pathway; meanwhile, it increased nicotinamide nucleotide transhydrogenase (NNT), the free-radical detoxifier, over 6-fold. Mechanically, phosphorylation at Thr423 & Ser424 translocated membrane Bin2 into cytoplasm to phosphorylate RPS6, while p-RPS6 bound 42-95 bp NNT UTR to inhibit NNT translation. We then synthesized a peptide (BPP) to mimic Bin2 inhibition, and found that 3-week BPP injection improved primordial follicle reserve and oocyte quality in aging or chemotherapeutics-treated mice. In all, Bin2 inhibition improve both primordial follicle reserve and oocyte quality without discernible side effects.