No abstract

Paternal life experiences impact offspring health via germline, and epigenetic inheritance provides a potential mechanism. However, global reprogramming during offspring embryogenesis and gametogenesis represents the largest hurdle to conceptualize it. Yet, detailed characterization of how sperm epigenetic alterations carrying “environmental memory” can evade offspring embryonic reprogramming remains elusive. Here, mice exposed to long-term restraint stress were employed to study the mechanisms underlying inter- and transgenerational effects of paternal exposure to a long-term psychological stress. We found that stress could induce paternal inheritance of reproductive, behavioral, and metabolic disorders. Bisulfite methylation profiling of 18 sperm and 12 embryo samples of three consecutive generations identified inter- and transgenerational inheritance of paternal Differential DNA Methylation Regions (DMRs) at frequencies ~11.36% and 0.48%, respectively. These DMRs related to genes with functional implications for psychological stress response, and tissue inheritance of these DMRs passed paternal disorders epigenetically to offspring. More importantly, these DMRs evaded offspring embryonic reprogramming through erasure and subsequent reestablishment, but not via un-erasure way. Nonetheless, their reestablishment proportions in the primitive streak (E7.5) stage were altered. Furthermore, sncRNA-seq revealed that stress-induced tsRNA, miRNA and rsRNA dysregulation in paternal sperm might play important roles in DMRs occurrence and paternal inheritance. These finding implied that sperm epigenetic alterations contribute to inter- and transgenerational effects of paternal exposure to long-term psychological stress, and highlighted the possible underlying molecular mechanism.

Male infertility is a rising problem around the world. Often the cause of male infertility is unclear, and this hampers diagnosis and treatment. Spermatogenesis is a complex process under sophisticated regulation by many testis‐specific genes. Here, we report the testis‐specific gene 1700102P08Rik is conserved in both the human and mouse and highly expressed in spermatocytes. To investigate the role of 1700102P08Rik in male fertility, knockout mice were generated by CRISPR‐Cas9. 1700102P08Rik knockout male mice were infertile with smaller testis and epididymis, but female knockout mice retained normal fertility. Spermatogenesis in the 1700102P08Rik knockout male mouse was arrested at the spermatocyte stage, and no sperm were found in the epididymis. The deletion of 1700102P08Rik causes apoptosis in the testis but did not affect the serum concentration of testosterone, luteinizing hormone, and follicle‐stimulating hormone or the synapsis and recombination of homologous chromosomes. We also found that 1700102P08Rik is downregulated in spermatocyte arrest in men. Together, these results indicate that the 1700102P08Rik gene is essential for spermatogenesis and its dysfunction leads to male infertility.

Seminal plasma contains a high concentration of extracellular vesicles (EVs). The heterogeneity of small EVs or the presence of non-vesicular extracellular matter (NV) pose major obstacles in understanding the composition and function of seminal EVs. In this study, we employed high-resolution density gradient fractionation to accurately characterize the composition and function of seminal EVs and NV. We found that the seminal EVs could be divided into three different subtypes, namely high-density EV (EV-H), medium-density EV (EV-M), and low-density EV (EV-L) after purification using iodixanol,while NV was successfully isolated. EVs and NV display different features in size, shape and expression of some classic exosome markers. Both EV-H and NV could markedly promote sperm motility and capacitation compared with EV-M and EV-L, whereas only the NV fraction induced sperm acrosome reaction. Proteomic analysis results showed that EV-H, EV-M, EV-L, and NV had different protein components and were involved in different physiological functions. Further study showed that EV-M might reduce the production of sperm intrinsic reactive oxygen species (ROS) through Glutathione S-transferase Mu 2 (GSTM2).This study provides novel insights into important aspects of seminal EVs constituents and sounder footing to explore their functional properties in male fertility.