ARS | Publication request: Vitamin D Signaling in the Bovine Mammary Gland is Part of the Innate Immune Response to Bacterial Pathogens

Submitted to: Mastitis Council Meeting Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: December 2, 2009
Publication Date: January 31, 2010
Citation: Nelson, C.D., Reinhardt, T.A., Lippolis, J.D. 2010. Vitamin D Signaling in the Bovine Mammary Gland is Part of the Innate Immune Response to Bacterial Pathogens [abstract]. National Mastitis Council. p. 196.

Technical Abstract: Vitamin D has been primarily known for the role it has in regulating calcium homeostasis, but we have recently found evidence that it is also involved in the immune response also. The active vitamin D metabolite is 1,25-dihydroxyvitamin (1,25[OH]2D3). Systemically, 1,25(OH)2D3 functions to regulate the expression of genes involved in calcium homeostasis (Horst et al., 2003). For that reason, the production of 1,25(OH)2D3 is tightly controlled. 1,25(OH)2D3 is produced from 25-hydroxyvitamin D3 by the enzyme 1alpha-hydroxylase (1alpha-OHase). For years, the kidney was thought to be the only site of 1,25(OH)2D3 production by 1alpha-OHase. However, we have recently found that 1,25(OH)2D3 is produced by 1alpha-OHase in bovine monocytes upon activation by toll-like receptor recognition of bacterial cell wall components. In activated monocytes, 1,25(OH)2D3 increases the expression of inducible nitric oxide synthase (iNOS) and the chemokine RANTES. Here we show for the first time that 1alpha-OHase is expressed in the mammary gland during mastitis; providing a mechanism to regulate vitamin D-mediated expression of iNOS and RANTES during mastitis.