Possible Involvement of a MEG3-miR-21-SPRY1-NF-κB Feedback Loop in Spermatogenic Cells Proliferation, Autophagy and Apoptosis

Non-obstructive azoospermia (NOA) is the most incurable form of male infertility with a complex etiology. Long non-cording RNAs (lncRNAs) were associated with regulating spermatogenesis. Herein, differentially expressed lncRNAs between NOA and control male were screened by RNA-seq analysis. MEG3 was upregulated in NOA tissues and inhibited cell proliferation and promoted cell autophagy and apoptosis in vitro. . Through RNA immunoprecipitation (RIP), biotin pull-down assays, and dual-luciferase reporter assays, MEG3 was proved to act as a competing endogenous RNA of microRNA (miR)-21 and thus influenced the SPRY1/ERK/mTOR signaling pathway. Additionally, bioinformatic prediction and chip assay revealed that MEG3 was possibly regulated by nuclear factor kappa B (NF-kappa B) and SPRY1/NF-kappa B/ MEG3 formed a feedback loop. Seminiferous tubule microinjection further investigated the effects of MEG3 on testes in vivo. These findings demonstrated that MEG3-miR-21-SPRY1-NF-kappa B probably acted as a feedback loop leading to azoospermia. Our study might provide a target and theoretical basis for and NOA.