Long noncoding RNAs (lncRNAs) are composed of nucleotides located in the nucleus and cytoplasm; these are transcribed by RNA polymerase II and are greater than 200 nt in length. LncRNAs fulfill important functions in a variety of biological processes, including genome imprinting, cell differentiation, apoptosis, stem cell pluripotency, X chromosome inactivation and nuclear transport. As high throughput sequencing technology develops, a substantial number of lncRNAs have been found to be related to a variety of biological processes, such as development of the testes, maintaining the self-renewal and differentiation of spermatogonial stem cells, and regulating spermatocyte meiosis. These indicate that lncRNAs can be used as biomarkers and potential therapeutic targets for male infertility. However, only a few comprehensive reviews have described the role of lncRNAs in male reproduction. In this paper, we summarize recent findings relating to the role of lncRNAs in spermatogenesis, their potential as biomarkers for male infertility and the relationship between reproductive arrest and transgenerational effects. Finally, we suggest specific targets for the treatment of male infertility from the perspective of lncRNAs.

Inhibin A is well known for its inhibitory properties against follicle-stimulating hormone (FSH), released through a pituitary–gonadal negative feedback loop to regulate follicular development. Ovarian folliculogenesis, hormonal biosynthesis, and gametogenesis are dependent on inhibins, playing vital roles in promoting or inhibiting cell proliferation. The present study explored the physiological and molecular response of bovine granulosa cells (GCs) to different concentrations of inhibin A in vitro. We treated the primary GCs isolated from ovarian follicles (3–6 mm) with different levels of inhibin A (20, 50, and 100 ng/mL) along with the control (0 ng/mL) for 24 h. To evaluate the impact of inhibin A on GCs, several in vitro cellular parameters, including cell apoptosis, viability, cell cycle, and mitochondrial membrane potential (MMP) were detected. Besides, the transcriptional regulation of pro-apoptotic (BAX, Caspase-3) and cell proliferation (PCNA, CyclinB1) genes were also quantified. The results indicated a significant (p < 0.05) increase in the cell viability in a dose-dependent manner of inhibin A. Likewise, MMP was significantly (p < 0.05) enhanced when GCs were treated with high doses (50, 100 ng/mL) of inhibin A. Furthermore, inhibin A dose (100 ng/mL) markedly improved the progression of the G1 phase of the cell cycle and increased the cell number in the S phase, which was supported by the up-regulation of the proliferating cell nuclear antigen PCNA (20, 50, and 100ng/mL) and CyclinB (100 ng/mL) genes. In addition, higher doses of inhibin A (50 and 100 ng/mL) significantly (p < 0.05) decreased the apoptotic rate in GCs, which was manifested by down regulating BAX and Caspase-3 genes. Conclusively, our study presented a worthy strategy for the first time to characterize the cellular adaptation of bovine GCs under different concentrations of inhibin A. Our results conclude that inhibin A is a broad regulatory marker in GCs by regulating apoptosis and cellular progression.

The Polled Celtic (Pc) mutation locus is a genetically simple single mutation that is the best choice for breeding polled cattle using gene editing. However, the mechanism of the Pc locus for regulating horn development is unclear, so we used gene editing, somatic cell nuclear transfer and embryo transfer to obtain polled Holstein fetal bovine (gestation time 90 days) with a homozygous Pc insertion (gene-edited Holstein fetal bovine, EH) and the wild-type 90 days Holstein fetal bovine (WH) as controls. The hematoxylin-eosin (HE) staining results showed that, compared to the WH, the EH horn buds had no white keratinized projections or vacuolated keratinocytes and no thick nerve bundles under the dermal tissue. Furthermore, DNA sequencing results showed that the Pc locus was homozygously inserted into the fetal bovine genome. A total of 791 differentially expressed genes were identified by transcriptome sequencing analysis. Enrichment analysis and protein interaction analysis results of differentially expressed genes showed that abundant gene changes after Pc insertion were associated with the adhesion molecule regulation, actin expression, cytoskeletal deformation and keratin expression and keratinization. It was also noted that the results contained several genes that had been reported to be associated with the development of horn traits, such as RXFP2 and TWIST1. This study identified these changes for the first time and summarized them. The results suggested that the Pc mutant locus may inhibit neural crest cell EMT generation and keratin expression, leading to failures in neural crest cell migration and keratinization of the horn bud tissue, regulating the production of the polled phenotype.

Spermatogenesis is a complex, tightly regulated biological process crucial for male fertility in mammals. MicroRNAs (miRNAs) and messenger RNAs (mRNAs) play essential functions in regulating gene expression during spermatogenesis, and their specific roles in Holstein bull testicular development remain unclear. The study analyzed testicular tissues from young and mature Holstein bulls, unveiling the post-sexual maturation transcriptome landscape with a focus on spermatogenesis-associated miRNAs and mRNA profiles. The cDNA libraries from the testicular tissues of three young Holstein bulls (X1, X2, and X3; group YB) and three mature Holstein bulls (D5, D6, and D7; group AB) were established for RNA-sequencing analysis using Illumina high-throughput sequencing technology, followed by bioinformatics analysis. A total of 1114 miRNAs were identified in the X vs. D groups: 683 known miRNAs and 431 novel miRNAs. Notably, 221 known miRNAs exhibit differential expression between the X and D groups, with 118 up-regulated and 103 down-regulated genes. Moreover, a total of 237 previously unidentified novel miRNAs were also observed to exhibit differential expression between X and D, with 77 up-regulated and 160 down-regulated miRNA genes. These miRNA genes were linked to Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to male reproduction and spermatogenesis. The DE analysis of miRNA genes identified the top five up-regulated miRNAs (bta-miR-127, bta-miR-495, bta-miR-493, bta-miR-432, and bta-miR-3956) and down-regulated miRNAs (bta-miR-34c, bta-miR-34b, bta-miR-449a, bta-miR-449b, and 23_28233-5p (hsa-miR-6774-3p)) between the young bull and adult bull groups. The miRNA-mRNA network analysis also identified 17_16057-5p, X_45311-3p (cpo-miR-12072-3p), bta-miR-34c, bta-miR-375, 17_15431-5p (eca-miR-8912), 10_2547-3p (isc-miR-5313), bta-miR-449b, and mRNA genes such as BCL2L11, ADAMTSI1, MED1, and PRDM1; these genes were associated with reproductive system development. The mRNA genes (STRB and BCL2L11) and miRNA genes (bta-miR-134, bta-let-7e, bta-miR-181b, and bta-miR-214) were also found to have a significant correlation with the spermatogenic process. Thus, the comprehensive analysis of miRNA and mRNA enhances our knowledge of the regulatory networks involved in testicular development and identifies potential targets for further investigation and manipulation to improve cattle reproductive efficiency and genetic selection.