Reduced vitamin D-induced cathelicidin production and killing of in macrophages from a patient with a non-functional vitamin D receptor: A case report.

Tuberculosis (TB) presents a serious health problem with approximately a quarter of the world's population infected with () in an asymptomatic latent state of which 5-10% develops active TB at some point in their lives. The antimicrobial protein cathelicidin has broad antimicrobial activity towards viruses and bacteria including . Vitamin D increases the expression of cathelicidin in many cell types including macrophages, and it has been suggested that the vitamin D-mediated antimicrobial activity against is dependent on the induction of cathelicidin.

Induced Human Regulatory T Cells Express the Glucagon-like Peptide-1 Receptor.

The glucagon-like peptide-1 receptor (GLP-1R) plays a key role in metabolism and is an important therapeutic target in diabetes and obesity. Recent studies in experimental animals have shown that certain subsets of T cells express functional GLP-1R, indicating an immune regulatory role of GLP-1. In contrast, less is known about the expression and function of the GLP-1R in human T cells.

Normal T and B Cell Responses Against SARS-CoV-2 in a Family With a Non-Functional Vitamin D Receptor: A Case Report.

The coronavirus disease 2019 (COVID-19) pandemic has severely impacted daily life all over the world. Any measures to slow down the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and to decrease disease severity are highly requested. Recent studies have reported inverse correlations between plasma levels of vitamin D and susceptibility to SARS-CoV-2 infection and COVID-19 severity.

Macrophages Control the Bioavailability of Vitamin D and Vitamin D-Regulated T Cell Responses.

The active form of vitamin D (1,25(OH)D) has a great impact on T cell effector function. Thus, 1,25(OH)D promotes T helper 2 (Th2) and regulatory T (Treg) cell function and concomitantly inhibits Th1 and Th17 cell function. Thus, it is believed that vitamin D exerts anti-inflammatory effects.

Vitamin D Inhibits IL-22 Production Through a Repressive Vitamin D Response Element in the Promoter.

Th22 cells constitute a recently described CD4 T cell subset defined by its production of interleukin (IL)-22. The action of IL-22 is mainly restricted to epithelial cells. IL-22 enhances keratinocyte proliferation but inhibits their differentiation and maturation.

Impaired Vitamin D Signaling in T Cells From a Family With Hereditary Vitamin D Resistant Rickets.

The active form of vitamin D, 1,25-dihydroxyvitamin D (1,25(OH)D), mediates its immunomodulatory effects by binding to the vitamin D receptor (VDR). Here, we describe a new point mutation in the DNA-binding domain of the VDR and its consequences for 1,25(OH)D signaling in T cells from heterozygous and homozygous carriers of the mutation. The mutation did not affect the overall structure or the ability of the VDR to bind 1,25(OH)D and the retinoid X receptor.

Tumor necrosis factor induces rapid down-regulation of TXNIP in human T cells.

In addition to antigen-driven signals, T cells need co-stimulatory signals for robust activation. Several receptors, including members of the tumor necrosis factor receptor superfamily (TNFRSF), can deliver co-stimulatory signals to T cells. Thioredoxin interacting protein (TXNIP) is an important inhibitor of glucose uptake and cell proliferation, but it is unknown how TXNIP is regulated in T cells.