1,25-Dihydroxyvitamin D3 potentiates the innate immune response of peripheral blood mononuclear cells from Japanese Black cattle.

1,25-Dihydroxyvitamin D3 (1,25(OH)2 D3 ), a bioactive vitamin D, is known to regulate immune responses in mammals. However, its impact on the innate immune responses of Japanese Black cattle, which are beef cattle endemic to Japan, remains unknown. Thus, in this study, we investigated the effect of 1,25(OH)2 D3 on the immune responses of peripheral blood mononuclear cells from Japanese Black cattle. As a result, the treatment of 1,25(OH)2 D3 upregulated the expression of antibacterial peptides, bovine beta-defensin 10 (DEFB10), and lingual antimicrobial peptide (LAP), in the presence and absence of lipopolysaccharide (LPS) stimulation. Moreover, 1,25(OH)2 D3 enhanced the inflammatory responses, including C-X-C motif ligand 8 (CXCL8) and nitric oxide synthase (NOS2), while reducing the expression of anti-inflammatory cytokine IL10, leading to an inflammatory phenotype. However, in contrast to humans and mice, 1,25(OH)2 D3 did not alter the expression of tumor necrosis factor (TNF) and downregulated triggering receptor expressed on myeloid cell 1 (TREM1) with LPS treatment. These results suggest that 1,25(OH)2 D3 potentiates the innate immune responses of Japanese Black cattle, albeit with different effects and mechanisms as compared to humans and mice.