Low fertility is the main cause of the low productivity in beef cattle and is mainly associated with a lack of conception after fertilization. The establishment of early pregnancy in cattle is a complex physiological process, and embryo implantation is crucial for the successful establishment of pregnancy. Exosomal miRNAs play an important role in regulating mammalian embryo implantation and development. This study used synchronous estrus technology to extract exosomes from bovine serum at 0, 14, and 21 days of early pregnancy and analyzed the expression profile of exosomal miRNAs through RNA-seq technology. We identified 472 miRNA precursor sequences and 367 mature miRNA sequences in the three sample groups, with the majority of the miRNAs having high abundance. Differentially expressed miRNAs (DEmiRNAs) were screened, and 20 DEmiRNAs were obtained. The differential expression analysis results show that compared to day 0, there were 15 DEmiRNAs in the serum on day 14 and 5 on day 21 of pregnancy. Compared to the 14th day of pregnancy, there were eight DEmiRNAs in the serum on the 21st day of pregnancy. Bioinformatics analysis shows that the target genes of DEmiRNAs regulated the signaling pathways closely related to early pregnancy, including the VEGF, NF-κB, and MAPK signaling pathways. In addition, the newly discovered miRNAs were bta-miR-3604, bta-miR-2889, bta-miR-3432a, and bta-miR-409b. These results provide a theoretical reference for screening the molecular markers for early pregnancy establishment and maternal recognition of pregnancy (MRP) in cattle and new ideas for shortening the calving interval in cows.

[目的]旨在进行牛钙调蛋白依赖性蛋白激酶4(Calmodulin-dependent protein kinase 4,CAMK4)基因编码区(Coding se-quence,CDS)的克隆、CAMK4蛋白的功能预测分析及CAMK4基因在西门塔尔牛各组织中的组织表达谱分析.[方法]采用RT-PCR结合测序技术获得牛CAMK4基因的CDS区,利用PortParam、ProtScale、SOPM A和DNAMAN等生物信息学在线工具进行CAMK4基因及其所编码蛋白质的序列分析,并利用qRT-PCR检测CAMK4基因在西门塔尔牛的心、肝、脾、肺、肾、肌肉和睾丸组织中的表达量.[结果]牛CAMK4基因CDS区的长度为801 bp,编码1条266个氨基酸组成的不稳定且无跨膜结构域的亲水的酸性蛋白质.牛CAMK4蛋白存在丝氨酸(Ser)、苏氨酸(Thr)和酪氨酸(Tyr)残基的19个磷酸化位点,主要在细胞质中发挥作用.该蛋白质含有1个蛋白激酶C超家族(PKc_like superfamily)结构域和1个尿嘧 啶DNA糖基化酶(PHA03201)结构域,同时,蛋白互作网络预测发现 CAMK4 蛋白可能与 HDAC5、HDAC4、CAMKK1、CALM、CREB1、CALM2、PLCG2、CAMKK2、CALML3 和 CALML5 蛋白有相互作用.CAMK4基因在西门塔尔牛睾丸组织中的表达量极显著高于心、肝、脾、肺、肾和肌肉组织.结合生物信息学分析结果,提示C4MK4基因可能参与调控细胞周期和免疫反应,并在精子发生及运动、精原干细胞自我更新等生物学过程发挥重要作用.[结论]本研究为进一步揭示牛CAMK4基因的功能和促进高繁殖力肉牛分子育种技术的研发提供基础资料.

Bovine oocytes are one of the indispensable cells in cattle reproduction and have become a research hot spot in cattle reproduction in recent years. The maturation process of oocytes is mainly regulated by enzymes, hormones, cytokines, and other molecules. The factors affecting cattle oocyte maturation have been previously studied to clarify the molecular mechanisms of cattle oocyte maturation. In this review article, phospholipid protein-3-kinase/protein kinase B, mitogen-activated protein kinase/extracellular signal-regulated kinase, Janus kinase/signal transducer and activator of transcription, epidermal growth factor receptor/extracellular signal-regulated kinase, and other signaling pathways related to oocyte maturation are discussed. In addition, the molecular mechanisms of some coding genes (JY-1, FGF-10, CDC20, etc.) and non-coding genes (miRNA, lncRNA, and circRNA) regulating oocyte maturation have been reviewed to provide new ideas for high reproductive performance molecular breeding of high-quality cattle.

Bovine mammary epithelial cells (bMECs) are involved in the early defense against the invasion of intramammary pathogens and are essential for the health of bovine mammary gland. MicroRNA (MiRNA) is a key factor that regulates cell state and physiological function. In the present study, the transcriptome profiles of miR-223 inhibitor transfection group (miR-223_Inhibitor) and negative control inhibitor transfection group (NC_Inhibitor) within bMECs were detected via the RNA sequencing (RNA-seq) platform. Based on these experiments, the differentially expressed mRNAs (DE-mRNAs) of the miR-223_Inhibitor transfection group were screened, and the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes functional analyses of DE-mRNAs were performed. The results revealed that compared with the NC_Inhibitor, 224 differentially expressed genes (DEGs) were identified in the miR-223_Inhibitor, including 184 upregulated and 40 downregulated genes. The functional annotation of the above DEGs indicated that some of these genes are involved in the immune response generated by extracellular substance stimulation, regulation of the activity of cytokines and chemokines, and the immune signaling pathways of NF-κB and TNF. Meanwhile, miR-223_inhibitor upregulated the immune key genes IRF1 and NFκBIA, cytokines IL-6 and IL-24, as well as chemokines CXCL3, CXCL5, and CCR6, triggering a signaling cascade response that exacerbated inflammation in bMECs. These results suggested that miR-223 plays an important role in inhibiting the inflammatory response and maintaining the stability of bMECs, and is a potential target for treating mastitis in dairy cows.

Long noncoding RNAs (lncRNAs) are recently discovered genetic regulatory molecules that regulate immune responses and are closely associated with the occurrence and development of various diseases, including inflammation, in humans and animals. Under specific physiological conditions, lncRNA expression varies at the cell or tissue level, and lncRNAs can bind to specific miRNAs, target mRNAs, and target proteins to participate in certain processes, such as cell differentiation and inflammatory responses, via the corresponding signaling pathways. This review article summarizes the regulatory role of lncRNAs in macrophage polarization, dendritic cell differentiation, T cell differentiation, and endothelial and epithelial inflammation. In addition, it describes the molecular mechanism of lncRNAs in acute kidney injury, hepatitis, inflammatory injury of the lung, osteoarthritis, mastitis, and neuroinflammation to provide a reference for the molecular regulatory network as well as the genetic diagnosis and treatment of inflammatory diseases in humans and animals.