Isolation, characterization, and SREBP1 functional analysis of mammary epithelial cell in buffalo

Regulatory impacts of PPARGC1A gene expression on milk production and cellular metabolism in buffalo mammary epithelial cells

The PPARGC1A gene plays a fundamental role in regulating cellular energy metabolism, including adaptive thermogenesis, mitochondrial biogenesis, adipogenesis, gluconeogenesis, and glucose/fatty acid metabolism. In a previous study, our group investigated seven SNPs in Mediterranean buffalo associated with milk production traits, and the current study builds on this research by exploring the regulatory influences of the PPARGC1A gene in buffalo mammary epithelial cells (BuMECs). Our findings revealed that knockdown of PPARGC1A gene expression significantly affected the growth of BuMECs, including proliferation, cell cycle, and apoptosis. Additionally, we observed downregulated triglyceride secretion after PPARGC1A knockdown. Furthermore, the critical genes related to milk production, including the STATS, BAD, P53, SREBF1, and XDH genes were upregulated after RNAi, while the FABP3 gene, was downregulated. Moreover, Silencing the PPARGC1A gene led to a significant downregulation of β-casein synthesis in BuMECs. Our study provides evidence of the importance of the PPARGC1A gene in regulating cell growth, lipid, and protein metabolism in the buffalo mammary gland. In light of our previous research, the current study underscores the potential of this gene for improving milk production efficiency and overall dairy productivity in buffalo populations.

Novel Insight into the Role of Squalene Epoxidase (SQLE) Gene in Determining Milk Production Traits in Buffalo

Understanding the genetic mechanisms underlying milk production traits contribute to improving the production potential of dairy animals. Squalene epoxidase (SQLE) is one of the rate-limiting enzymes for cholesterol biosynthesis and was highly expressed in the buffalo mammary. The objectives of the present study were to detect the polymorphisms within SQLE in buffalo, the genetic effects of these mutations on milk production traits, and to understand the gene regulatory effects on buffalo mammary epithelial cells (BuMECs). A total of five SNPs were identified by sequencing, g.18858G > A loci were significantly associated with fat yield, and g.22834C > T loci were significantly associated with peak milk yield, milk yield, fat yield, and protein yield. Notably, linkage disequilibrium analysis indicated that 2 SNPs (g.18858G > A and g.22834C > T) formed one haplotype block, which was found to be significantly associated with milk fat yield, fat percentage, and protein yield. Furthermore, expression of SQLE was measured in different tissues of buffalo and was found to be higher in the mammary. Knockdown of SQLE gene expression significantly affected the growth of BuMECs, including proliferation, cell cycle, and apoptosis, and significantly downregulated the expression of related genes MYC, PCNA, and P21. In addition, knockdown of the SQLE gene significantly reduces triglyceride concentrations and the signal intensity of oil red O staining. In addition, silencing of SQLE was also found to regulate the synthesis and secretion of β-casein and κ-casein negatively. Furthermore, SQLE knockdown is accompanied by the downregulation of critical genes (RPS6KB1, JAK2, eIF4E, and SREBP1) related to milk fat and protein synthesis. The current study showed the potential of the SQLE gene as a candidate for buffalo milk production traits. It provides a new understanding of the physiological mechanisms underlying buffalo milk production regulation.

Transcriptional profiling of buffalo mammary gland with different milk fat contents

Milk fat is the most important energy substance in milk and contributes to its quality and health benefits. Water buffalo milk is well known for its high milk quality with higher fat contents compared with cattle milk. Dehong buffalo is a unique local swamp breed in Yunnan Province with higher milk fat and excellent milk quality which provides a good model for the investigation of the molecular mechanisms of milk fat deposition. In this study, we used RNA-seq to obtain mammary tissue transcriptomics of buffalo with different milk fat phenotypes including high(H), medium (M)and low (L) fat content groups. Comparative analyses of buffalo among three groups yielded differentially expressed genes (DEGs). Analyzing the number of different genes among H_VS_L, H_VS_M, and M_VS_L showed the same expression pattern between H_VS_M. The increasing expression levels of genes including CSN1S1, BTN1A1, LALBA, ALDH1L2, SCD and MUC15, and down-regulated expression levels of genes containing CCL2, CRABP2, ADTRP, CLU and C4A in H_VS_L and M_VS_L were found. GO and KEGG enriched pathways revealed these DEGs involved in milk protein and fat as well as immune response. The findings would enhance the understanding of the interplay between the milk composition and immune response, which suggests that the immune capacity should be considered when we tried to improve the milk quality.