Effects of 1,25-Dihydroxyvitamin D3 and 25-Hydroxyvitamin D3 on PBMCs From Dairy Cattle Naturally Infected With Mycobacterium avium subsp. paratuberculosis

Taylor L T Wherry; Shankumar Mooyottu; Judith R Stabel

doi:10.3389/fvets.2022.830144

Effects of 1,25-Dihydroxyvitamin D₃ and 25-Hydroxyvitamin D₃ on PBMCs From Dairy Cattle Naturally Infected With Mycobacterium avium subsp. paratuberculosis

Front Vet Sci. 2022 Feb 8:9:830144. doi: 10.3389/fvets.2022.830144. eCollection 2022.

Authors

Taylor L T Wherry^{1

2}, Shankumar Mooyottu², Judith R Stabel¹

Affiliations

¹ Infectious Bacterial Diseases, National Animal Disease Center, United States Department of Agriculture-Agricultural Research Service, Ames, IA, United States.
² Department of Veterinary Pathology, Iowa State University, Ames, IA, United States.

Abstract

The role of vitamin D₃ in modulating immune responses has been well-established for over two decades; however, its specific functions have not been extensively detailed in cattle, particularly cattle in different stages of infection with Mycobacterium avium subspecies paratuberculosis (MAP). Consistent with previous work in our lab, the present study showed that infected cattle in the clinical stage of disease have reduced serum 25-hydroxyvitamin D₃ [25(OH)D₃]. Additionally, effects of vitamin D₃ on peripheral blood mononuclear cells (PBMCs) from naturally infected dairy cattle in subclinical (n = 8) or clinical (n = 8) stages of infection were compared to non-infected control cows (n = 8). Briefly, PBMCs were isolated and cultured in vitro with 4 ng/ml 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] or 100 ng/ml 25(OH)D₃. Treatment with 1,25(OH)₂D₃ resulted in decreased secretion for some pro-inflammatory cytokines in clinical animals, including IL-1β, IL-6, and IFN-γ. Similar responses for IL-1β and IL-6 were noted with the addition of 25(OH)D₃. Additionally, pro-inflammatory cytokine gene expression tended to be upregulated in PBMCs from clinical animals after treatment with 1,25(OH)₂D₃. In contrast, PBMCs from clinical animals treated with 25(OH)D₃ showed downregulation of pro-inflammatory cytokine gene expression, although only significant for IL1B. Following 25(OH)D₃ treatment, clinical animals showed significant reduction in CD4+CD25+ T cells. CYP27B1 gene expression was notably decreased in clinical and control animals following 25(OH)D₃ treatment but increased in subclinical cows. 1,25(OH)₂D₃ treatment reduced CYP24A1 gene expression in all groups, while 25(OH)D₃ treatment only significantly reduced expression for control cows. Lastly, serum 25(OH)D₃ levels were significantly lower in clinical animals. Taken together, these data show vitamin D₃ modulates cytokine signaling in cattle at different stages of MAP infection and, therefore, may have implications on disease progression.

Keywords: Johne's disease; Mycobacterium avium subsp. paratuberculosis; PBMC; cattle; immune responses; vitamin D.