RESUMO
Staphylococcus aureus is a major pathogen of subclinical bovine mastitis that usually is chronic and recurrent, which has been related to its ability to internalize into bovine mammary epithelial cells (bMECs). Previously, we reported that short and medium fatty acids and cholecalciferol reduce S. aureus internalization into pretreated-bMECs with these molecules suggesting a role as immunomodulatory agents. Hence, we assessed the role of sodium butyrate (NaB), sodium octanoate (NaO) and cholecalciferol on S. aureus adhesin expression and its internalization into bMECs. S. aureus pre-treated 2â¯h with 0.5â¯mM or 2â¯mM NaB showed a reduction in internalization into bMECs (â¼35% and â¼55%; respectively), which coincided with a down-regulated expression of clumping factor B (ClfB). Also, the S. aureus internalization reduction by 2â¯mM NaB (2â¯h) agreed with a down-regulated expression of sdrC. Moreover, the 2â¯mM NaB (24â¯h) pre-treatment induced bacterial internalization (â¼3-fold), which was related with an up-regulation of spa, clfB and sdrC genes. Also, NaO (0.25â¯mM and 1â¯mM) only reduced S. aureus internalization when bacteria were grown 2â¯h with this molecule but there was no relationship with adhesin expression. In addition, cholecalciferol (50â¯nM) reduced bacteria internalization at similar levels (â¼50%) when bacteria were grown 2 and 24â¯h in broth supplemented with this compound, which correlated with spa and sdrC mRNA expression down-regulated at 2â¯h, and fnba and clfB mRNA expression decreased at 24â¯h. In conclusion, our data support the fact that fatty acids and cholecalciferol regulate adhesin gene expression as well as bacteria internalization in nonprofessional phagocytic cells, which may lead to development of anti-virulence agents for control of pathogens.