Immunomodulatory Properties of Vitamin D in the Intestinal and Respiratory Systems

Abstract

Vitamin D plays a crucial role in modulating the innate immune response by interacting with its intracellular receptor, VDR. In this review, we address vitamin D/VDR signaling and how it contributes to the regulation of intestinal and respiratory microbiota. We additionally review some components of the innate immune system, such as the barrier function of the pulmonary and intestinal epithelial membranes and secretion of mucus, with their respective modulation by vitamin D. We also explore the mechanisms by which this vitamin D/VDR signaling mounts an antimicrobial response through the transduction of microbial signals and the production of antimicrobial peptides that constitute one of the body’s first lines of defense against pathogens. Additionally, we highlight the role of vitamin D in clinical diseases, namely inflammatory bowel disease and acute respiratory distress syndrome, where excessive inflammatory responses and dysbiosis are hallmarks. Increasing evidence suggests that vitamin D supplementation may have potentially beneficial effects on those diseases.

Vitamin D Supplementation in Neonatal and Infant MIS-C Following COVID-19 Infection

“…In particular, the vitamin D/VDR complex is known to modulate both the way in which pathogens are recognized (e.g., by influencing the pathogen recognition receptors) and the host's responses (e.g., NF-kB-and IL1β-driven downstream responses). In addition to directly regulating the transcription of cathelicidins and defensins, the vitamin D/VDR complex is also able to regulate the cytosolic components of the pathogen recognition system, such as the inflammasome-driven response [103,111].…”

Exposure to a Vitamin D Best Practices Toolkit, Model, and E-Tools Increases Knowledge, Confidence, and the Translation of Research to Public Health and Practice

“…Vitamin D plays a significant role in most physiologic and pathologic processes in the body, including DNA repair mechanisms, the prevention of cancer cell proliferation, lowering viral replication rates, antimicrobial defenses, lowering pro-inflammatory cytokine concentrations, the balance of the microbiota, innate and adaptive immune system homeostasis, and gene expression [35,[39][40][41]. A 2019 randomized controlled double-blind clinical trial (RCT) demonstrated a dose-dependent relationship between vitamin D3 supplementation and gene expression, showing the up-or down-regulation of 1289 identified genes with the daily supplementation of 10,000 IU/day compared to 320 genes with the supplementation of 4000 IU/day and 162 genes with the supplementation of 600 IU/day [42].…”