Lactiplantibacillus plantarum promotes lactoferrin synthesis and secretion in bovine mammary epithelial cells through STAT3 and AP-1 transcription factor pathways.

Probiotics can support the immune function of dairy cows and contribute to the synthesis of milk components in mammary gland tissue. Bovine lactoferrin (bLF) possesses immune-regulating and nutritional properties; however, the impact of probiotics on bLF remains unclear. This study aimed to investigate whether probiotics can enhance the synthesis and secretion of bLF in the mammary gland, with a particular focus on the specific mechanisms by which Lactiplantibacillus plantarum (L. plantarum) regulates bLF. Primary bovine mammary epithelial cells (BMECs) were cultured in six-well plates and treated with various types of probiotics. The expression of bLF was evaluated using quantitative real-time PCR (qRT-PCR), Western blot, and enzyme-linked immunosorbent assay (ELISA). The expression of transcription factors associated with the bLF promoter region, specifically, was analyzed through qRT-PCR and Western blot. Lacticaseibacillus rhamnosus (L. rhamnosus), Streptococcus thermophilus (S. thermophilus), Bifidobacterium (Bifido.), and L. plantarum upregulated bLF gene and protein expression to varying extents, with L. plantarum exhibiting the most pronounced effect. Furthermore, L. plantarum was found to regulate the expression of phosphorylated STAT3 and AP-1. These findings indicate that probiotics can influence the expression of bLF in mammary gland tissue. Additionally, L. plantarum modulates the production of bLF via the STAT3 and AP-1 transcription factor pathways.