Background: ISGylation is a post-translational protein modification that regulates many life activities, including immunomodulation, antiviral responses, and embryo implantation. The exact contribution of ISGylation to folliculogenesis remains largely undefined. Results: Here, Isg15 knockout in mice causes hyperfertility along with sensitive ovarian responses to gonadotropin, such as increases in cumulus expansion and ovulation rate. Moreover, ISG15 represses the expression of ovulation-related genes in an ISGylation-dependent manner. Mechanistically, ISG15 binds to ADAMTS1 via the ISG15-conjugating system (UBA7, UBE2L6, and HERC6), ISGylating ADAMTS1 at the binding sites Lys309, Lys593, Lys597, and Lys602, resulting in ADAMTS1 degradation via a 20S proteasome-dependent pathway. Conclusion: Taken together, the present study demonstrates that covalent ISG15 conjugation produces a novel regulatory axis of ISG15-ADAMTS1 that enhances the degradation of ADAMTS1, thereby compromising ovulation and female fertility.

Bisphenol AF (BPAF) is a newly identified contaminant in the environment that has been linked to impairment of the male reproductive system. However, only a few studies have systematically studied the mechanisms underlying BPAF-induced toxicity in testicular Sertoli cells. Hence, this study primarily aims to explore the toxic mechanism of BPAF on the porcine Sertoli cell line (ST cells). The effects of various concentrations of BPAF on ST cell viability and cytotoxicity were evaluated using the Counting Kit-8 (CCK-8) assay. The results demonstrated that exposure to a high concentration of BPAF (above 50 μM) significantly inhibited ST cell viability due to marked cytotoxicity. Flow cytometry analysis further confirmed that BPAF facilitated apoptosis and induced cell cycle arrest in the G2/M phase. Moreover, BPAF exposure upregulated the expression of pro-apoptotic markers BAD and BAX while downregulating anti-apoptotic and cell proliferation markers BCL-2, PCNA, CDK2, and CDK4. BPAF exposure also resulted in elevated intracellular levels of reactive oxygen species (ROS) and malondialdehyde (MDA), alongside reduced activities of the antioxidants glutathione (GSH), catalase (CAT), and superoxide dismutase (SOD). Furthermore, the ROS scavenger N-acetyl-L-cysteine (NAC) effectively blocked BPAF-triggered apoptosis and cell cycle arrest. Therefore, this study suggests that BPAF induces apoptosis and cell cycle arrest in ST cells by activating ROS-mediated pathways. These findings enhance our understanding of BPAF’s role in male reproductive toxicity and provide a foundation for future toxicological assessments.

Porcine skeletal muscle development is closely linked to meat production efficiency and quality. The accumulation of porcine intramuscular fat is influenced by the hyperplasia and hypertrophy of adipocytes within the muscle. However, the cellular profiles corresponding to the two stages of muscle development remain undetermined. Single-nucleus RNA sequencing (snRNA-seq) can elucidate cell subsets in tissues, capture gene expression at the individual cell level, and provide innovative perspectives for studying muscle and intramuscular fat formation. In this study, a total of 78,302 nuclei and 9 clusters of cells, which included fibro/adipogenic progenitor (FAP), myonuclei, adipocytes, and other cell types, of Xidu black pigs, were identified on Day 1 and Day 180. The pattern of cell clustering varied between the two developmental stages. Notably, the percentage of adipocytes in the Day 180 group was higher than in the Day 1 group (0.51% vs. 0.15%). Pseudo-time sequence analysis indicated that FAPs could differentiate into adipocytes and myonuclei cells, respectively. The THRSP gene was identified as a biomarker for swine intramuscular fat cells, and its down-regulation resulted in significant reduction in lipid droplet formation in porcine preadipocytes. Our research provides new insights into the cellular characteristics of intramuscular fat formation, which may facilitate the development of novel strategies to enhance intramuscular fat deposition and improve pork quality.

Intramuscular fat (IMF) content plays a crucial role in determining pork quality. Recent studies have highlighted transcriptional mechanisms controlling adipogenesis in porcine IMF. However, the changes in chromatin accessibility during adipogenic differentiation are still not well understood. In this study, we performed the assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and transcriptome sequencing (RNA-Seq) analyses on porcine intramuscular preadipocytes to explore their adipogenic differentiation into mature adipocytes. We identified a total of 56,374 differentially accessible chromatin peaks and 4226 differentially expressed genes at day 0 and day 4 during adipogenic differentiation. A combined analysis of the ATAC-seq and RNA-seq data revealed that 1750 genes exhibited both differential chromatin accessibility and differential RNA expression during this process, including selenium-binding protein 1 (SELENBP1), PLIN1, ADIPOQ, and FASN. Furthermore, we found that vitamin D receptor (VDR) could bind to the promoter region of the SELENBP1 gene, activate SELENBP1 transcription, and ultimately promote lipid accumulation during adipogenic differentiation. This study provides a detailed overview of chromatin accessibility and gene expression changes during the adipogenic differentiation of porcine intramuscular preadipocytes. Moreover, we propose a novel regulatory mechanism involving the VDR–SELENBP1 signaling axis in adipogenic differentiation.

DNA methylation plays a critical role in regulating gene expression during testicular development. However, few studies report on candidate genes related to the DNA methylation regulation of porcine testicular development. This study examined the differentially expressed genes (DEGs) and their methylation levels in testicular tissues from pigs at 60 days of age (60 d) and 180 days of age (180 d) using RNA-Seq and whole genome bisulfite sequencing (WGBS). It was determined that DNA methylation primarily occurs in the cytosine–guanine (CG) context, and the analysis identified 106,282 differentially methylated regions (DMRs) corresponding to 12,385 differentially methylated genes (DMGs). Further integrated analysis of RNA-Seq and WGBS data revealed 1083 DMGs negatively correlated with the expression of DEGs. GO analysis showed that these genes were significantly enriched in spermatogenesis, germ cell development, and spermatid differentiation. The screening of enriched genes revealed that hyper-methylation repressed ADAM30, ADAM3A, DPY19L2, H2BC1, MAK, RPL10L, SPATA16, and YBX2, while hypo-methylation elevated CACNA1I, CADM1, CTNNB1, JAM2, and PAFAH1B3 expression. Additionally, the methylation status of the key genes ADAM3A, ADAM30, YBX2, JAM2, PAFAH1B3, and CTNNB1 was detected by bisulfite sequencing PCR (BSP). This study offers insights into the epigenetic regulation mechanisms underlying porcine testicular development.

Growth traits, as core economic indicators in pig breeding, are closely associated with production costs, rearing duration, and final carcass quality and have thus consistently been a major focus of genetic improvement. This study aimed to identify candidate genes affecting Age to 120 kg live weight (AGE120), Backfat thickness at 120 kg (BF120), and Loin muscle depth at 120 kg (LMD120) in pigs. Ear tissue samples were collected from 3364 healthy adult pigs (including 558 boars and 2805 sows) from three breeds: Large White, Landrace, and Duroc. Genotyping was performed using an 80 K functional site array, and quality-controlled SNP (Single-Nucleotide Polymorphism) loci were subjected to genotype imputation, resulting in 15,447,611 loci obtained. Genome-wide association studies (GWASs) for Age to 120 kg live weight, Back fat thickness at 120 kg, and Loin muscle depth at 120 kg were conducted using a mixed linear model in Genome-wide Complex Trait Analysis (GCTA). Genes located within 500 kb upstream and downstream of significant GWAS loci were extracted using the biomaRt package in R. Furthermore, colocalization analysis was performed using expression Quantitative Trait Locus (eQTL) data of 34 tissues from the PigGTEx database to identify genes that share the same causal variant as the GWAS signals. Through integrated GWAS and eQTL colocalization analysis, in addition to five previously reported genes associated with pig growth traits (TAF11, ZC3HAV1L, ANKS1A, USP20, and TBC1D1), a set of novel, high-confidence candidate genes was identified: ZNF215, UBE2Z, HOXB7, SARDH, ADAMTSL2, ATP6V0A4, RPL10A, PGM2, and RELL1. These findings enrich our understanding of the genetic architecture underlying growth traits in pigs at heavy body weights and provide an important foundation for subsequent functional validation and molecular breeding applications.