Recent evidence suggests that testosterone deficiency can dramatically decrease the quality of sperm. MicroRNAs (miRNAs) are conserved mediators of post-transcriptional gene regulation in eukaryotes. However, the systemic regulation and function of miRNAs in sperm quality decline induced by testosterone deficiency has not been investigated. Here, we found that the sperm apoptosis was significantly enhanced and the sperm motility was dramatically decreased in hemicastrated pigs. We then used small RNA sequencing to detect miRNA profiles of sperm from pigs with prepubertal hemicastration (HC) and compared them with control libraries. We identified 16 differentially expressed (DE) miRNAs between the sperm of prepubertal HC and control (CT) pigs. Functional enrichment analysis indicated that the target genes of these DE miRNAs were mainly enriched in apoptosis-related pathways including the p53, mitogen-activated protein kinase (MAPK), and mammalian target of rapamycin (mTOR) pathways. Furthermore, gain- and loss-of-function analyses demonstrated potential anti-apoptotic effects of the DE miRNAs miR-26a-5p and let-7g-5p on sperm cells. The luciferase reporter assay confirmed that PTEN and PMAIP1 are targets of miR-26a-5p and let-7g-5p, respectively. Spearman’s correlation analysis revealed significantly positive correlations between the sperm and its corresponding seminal plasma exosomes regarding the miRNA expression levels. In conclusion, testosterone deficiency-induced changes in the miRNA components of seminal plasma exosomes secreted by the genital tract may partially elucidate sperm miRNAome alterations, which are further responsible for the decline of sperm motility.

Acute myocardial infarction (AMI) is an ischemic heart disease with high mortality worldwide. AMI triggers a hypoxic microenvironment and induces extensive myocardial injury, including autophagy and apoptosis. MiRNAs, which are a class of posttranscriptional regulators, have been shown to be involved in the development of ischemic heart diseases. We have previously reported that hypoxia significantly alters the miRNA transcriptome in rat cardiomyoblast cells (H9c2), including miR-27a-5p. In the present study, we further investigated the potential function of miR-27a-5p in the cardiomyocyte response to hypoxia, and showed that miR-27a-5p expression was downregulated in the H9c2 cells at different hypoxia-exposed timepoints and the myocardium of a rat AMI model. Follow-up experiments revealed that miR-27a-5p attenuated hypoxia-induced cardiomyocyte injury by regulating autophagy and apoptosis via Atg7, which partly elucidated the anti-hypoxic injury effects of miR-27a-5p. Taken together, this study shows that miR-27a-5p has a cardioprotective effect on hypoxia-induced H9c2 cell injury, suggesting it may be a novel target for the treatment of hypoxia-related heart diseases.

Commensal microbial–host interaction is crucial for host metabolism, growth, development, and immunity. However, research on microbial–host immunity in large animal models has been limited. This study was conducted to investigate the effects of the commensal microbiota on immune function in two model groups: germ-free (GF) and specific-pathogen-free (SPF) piglets. The weight and organ index of the spleen of the GF piglet were larger than those in the SPF piglet (P < 0.05). The histological structure of the red pulp area and mean area of germinal centers were larger in the SPF piglet than in the GF piglet (P < 0.05), whereas the areas of staining of B cells and T cells in the spleen and mesenteric lymph nodes (MLNs) were lower in the GF piglet (P < 0.05). We identified immune-related genes in the spleen and MLNs using RNA sequencing, and used real-time quantitative PCR to analyze the expression of core genes identified in gene set enrichment analysis. The expression levels of genes in the transforming growth factor-β/SMAD3 signaling pathway, Toll-like receptor 2/MyD88/nuclear factor-κB signaling pathway, and pro-inflammatory factor genes IL-6 and TNF-α in the spleen and MLNs were higher in the SPF piglet and in splenic lymphocytes compared with those in the GF and control group, respectively, under treatment with acetic acid, propionic acid, butyric acid, lipopolysaccharide (LPS), or concanavalin A (ConA). The abundances of plasma cells, CD8⁺⁺ T cells, follicular helper T cells, and resting natural killer cells in the spleen and MLNs were significantly greater in the SPF piglet than in the GF piglet (P < 0.05). In conclusion, the commensal microbiota influenced the immune tissue structure, abundances of immune cells, and expression of immune-related pathways, indicating the importance of the commensal microbiota for spleen and MLNs development and function. In our study, GF piglet was used as the research model, eliminating the interference of microbiota in the experiment, and providing a suitable and efficient large animal research model for exploring the mechanism of “microbial-host” interactions.