Xu Liu

Background: Mastitis, one of the most prevalent inflammatory diseases in female mammals, causes significant economic losses in livestock farming. Notably, the natural flavonoid compound baicalin exhibits potent anti-inflammatory activity. However, its efficacy in alleviating mastitis severity and the underlying molecular mechanisms remain unexplored. Therefore, this study aims to investigate the protective effects of baicalin in alleviating mastitis and its key molecular mechanisms. Results: This study demonstrated in vivo that baicalin effectively alleviates mastitis symptoms in dairy cows and mice, primarily manifested by reduced tissue pathological damage, decreased levels of pro-inflammatory cytokines, and maintain the integrity of the blood-milk barrier (BMB). Multi-omics sequencing analysis indicated that IL-17 and TNF signaling pathways play crucial roles in this process. Further studies demonstrated that IL-17RA ^−/− mice exhibited a phenotype similar to that observed with baicalin treatment, confirming the importance of this pathway. Notably, network pharmacology screening combined with molecular dynamics simulations revealed stable binding of baicalin to IL-17RA, suggesting that baicalin exerts its protective effect to alleviate mastitis by targeting IL-17RA. Mechanistically, both baicalin treatment and IL-17RA deletion block activation of key downstream pathways of the IL-17 signaling pathway, including MAPK, ERK and NF-κB, thereby suppressing excessive activation of the TNF signaling pathway, preventing exacerbation of the inflammatory response and barrier damage. Conclusions: In conclusion, this study demonstrates that baicalin inhibits excessive activation of the IL-17/TNF signaling pathway by targeting IL-17RA, thereby reducing inflammatory responses and BMB damage within the mammary gland and alleviating mastitis severity.

ADIPOQ plays a crucial role in regulating the reproductive system, but there are few reports on the effects of ADIPOQ on ovarian in dairy cows. Previous studies have verified the presence of a 67-bp mutation in the promoter region of the ADIPOQ gene. Hence, we employed ovarian tissues (n = 2111) and blood samples (n = 108) from Chinese Holstein cows as experimental samples to examine the association between ADIPOQ promoter variants and ovarian traits. We extracted DNA from these samples and conducted genetic typing identification on each sample using advanced techniques like PCR and agarose gel electrophoresis. Consequently, the DD, ID, and II genotypes were discovered. and it has been observed that the mutation frequency of this locus is low in the Chinese Holstein cow. Importantly, the correlational analysis unveiled a significant relationship (p < 0.05) between the weight of ovaries in late estrus and the width of ovaries during the estrus interval with the mutation. Result of the RT-PCR revealed that the ID genotype partially diminished the expression of the ADIPOQ gene. The results of this study suggest that the identified variable duplication could serve as a potential genetic marker for enhancing the ovarian traits of Chinese Holstein cows.

Animal cloning can be achieved by somatic cell nuclear transfer (SCNT), but the resulting live birth rate is relatively low. We previously improved the efficiency of bovine SCNT by exogenous melatonin treatment or by overexpression of lysine-specific demethylase 4D (KDM4D) and 4E (KDM4E). In this study, we revealed abundant alternative splicing (AS) transitions during fertilization and embryonic genome activation, and demonstrated abnormal AS in bovine SCNT embryos compared with in vitro fertilized embryos. We used the CRISPR-Cas13d RNA-targeting system to target cis-elements of ABI2 and ZNF106 pre-mRNA to modify AS, thus reducing the ratio of abnormal-isoform SCNT embryos by nearly 50% and achieving a high survival rate (11%–19%). These results indicate that this system may provide an efficient method for bovine cloning, while also paving the way for further improvements in the efficiency of SCNT.

Alternative splicing (AS) of mRNA precursors allows the synthesis of multiple mRNAs from a single primary transcript, significantly expanding the information content and regulatory possibilities of higher eukaryotic genomes. During mammalian development, AS drives certain decisive changes in different physiological processes. As development progresses, the maternal-to-zygotic transition (MZT) will trigger two processes: elimination of a subset of maternal mRNA and transcription of the zygote genome begins. Recent high-throughput technological advancements have facilitated genome-wide AS, whereas its analysis in mouse oocyte transition to the zygote stage has not been reported. We present a high-resolution global analysis of AS transitions and discovered extensive AS transitions between mouse oocyte and zygote. The difference of AS patterns was further confirmed using reverse transcription-polymerase chain reaction analysis. Many genes with specific AS events in mouse oocytes are differentially expressed between oocyte and zygote, but only a few genes with specific AS events in zygote are differentially expressed between oocyte and zygote. We provide a landscape of AS events in mouse oocyte and zygote. Our results advance the understanding of AS transitions during mouse fertilization and its potential functions for MZT and further development.