BDH1 acetylation at K116 modulates milk fat production in dairy goats

Goat milk is increasing valued for its superior nutritional profile, digestibility, and unique compositional properties. Protein acetylation, a pivotal post-translational modification, plays a critical role in the regulation of biosynthesis and metabolic processes. This study aims to identify key acetylated proteins and their modification sites governing milk production and the synthesis of milk components in dairy goats. Our findings establish a mechanistic foundation for elucidating molecular regulation of lactation and enhancing milk quality through targeted breeding strategies.

The acetylome profile of mammary gland tissues in dairy goats was successfully established. A total of 862 significantly acetylated proteins were identified across two lactation phases, and a total of 2,028 acetylation modified sites were identified in mammary gland tissues in dairy goats. Differentially acetylated proteins were predominantly localized in the cytoplasm (39.98%). From these, 54 key acetylated proteins, including MTOR, BCAT2, QARS1, GOT1, GOT2, BDH1, ACSS1, STAT5B, FABP5, and GPAM were identified as candidates potentially involved in milk protein synthesis, milk lipid synthesis, lactose synthesis, and other lactation-related biological processes in dairy goats.Among them, the acetylation modification of the β-hydroxybutyrate dehydrogenase 1 (BDH1) protein was characterized in dairy goats. The HDACs family was identified as primary regulators mediating the deacetylation of BDH1. Acetylation of BDH1 promoted the expression of LXRα, ACSL1 and SCD1genes, while its deacetylation induced the expression of SCD1, FASN and ACSL1 genes. BDH1 acetylation/deacetylation significantly reduced the expression of the SREBP1 gene. Furthermore, BDH1 acetylation promoted the formation of lipid droplets and the synthesis of triglycerides in mammary epithelial cells of dairy goats (GMECs).

This study established, for the first time, the comprehensive acetylome of mammary gland tissue in dairy goats, revealing a substantial number of differentially acetylated proteins and modification sites. We demonstrate that acetylation of BDH1-regulated by HDACs-promotes lipid droplet biogenesis and triglyceride synthesis in GMECs through transcriptional modulation of key lipogenic genes (LXRα, ACSL1, SCD1, FASN) and suppression of SREBP1. These findings provide novel mechanistic insights into the post-translational regulation of mammary lipid metabolism during lactation.