Vitamin D endocrinology on the cross-road between immunity and metabolism

- Cellular metabolic pathways determine the phenotype and function of specific immune subsets.
- 1,25(OH)2D3 has potent immunomodulatory effects in cells of the innate and adaptive immune system.
- Macrophages and DCs shift their intracellular metabolism under influence of 1,25(OH)2D3.
- Better understanding of metabolic pathways will contribute to generation/improvement of cell-based immunotherapies.

The effects of vitamin D on the immune function have been recognized for more than a quarter of a century. However, our understanding of the multifactorial nature of the effects of vitamin D at the cellular, molecular and metabolic level in different immune cells of the innate and adaptive immune system has dramatically progressed during the last decades. In this review, we summarize the main metabolic pathways preferentially used in different subsets of macrophages, dendritic cells, T and B cells as well as the immunomodulatory effects of vitamin D on these cells. We will highlight the metabolic reprogramming happening in vitamin D-conditioned tolerogenic dendritic cells. A better knowledge of the dynamics of metabolic states in immune subsets and their possible roles in inflammation and autoimmunity may advance the development of novel immunotherapies. Likewise, the implications of effects of vitamin D on immunometabolism may progress our insights in the nature of immune responses in health and disease.