AUTHOR=Cantorna Margherita T. , Lin Yang-Ding , Arora Juhi , Bora Stephanie , Tian Yuan , Nichols Robert G. , Patterson Andrew D. 

TITLE=Vitamin D Regulates the Microbiota to Control the Numbers of RORγt/FoxP3+ Regulatory T Cells in the Colon

JOURNAL=Frontiers in Immunology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2019.01772

DOI=10.3389/fimmu.2019.01772

ISSN=1664-3224

ABSTRACT=<p>The active form of vitamin D (1,25(OH)<sub>2</sub>D) suppresses experimental models of inflammatory bowel disease in part by regulating the microbiota. In this study, the role of vitamin D in the regulation of microbe induced RORγt/FoxP3+ T regulatory (reg) cells in the colon was determined. Vitamin D sufficient (D+) mice had significantly higher frequencies of FoxP3+ and RORγt/FoxP3+ T reg cells in the colon compared to vitamin D deficient (D–) mice. The higher frequency of RORγt/FoxP3+ T reg cells in D+ colon correlated with higher numbers of bacteria from the <italic>Clostridium</italic> XIVa and <italic>Bacteroides</italic> in D+ compared to D– cecum. D– mice with fewer RORγt/FoxP3+ T reg cells were significantly more susceptible to colitis than D+ mice. Transfer of the cecal bacteria from D+ or D– mice to germfree recipients phenocopied the higher numbers of RORγt/FoxP3+ cells and reduced susceptibility to colitis in D+ vs. D– recipient mice. 1,25(OH)<sub>2</sub>D treatment of the D– mice beginning at 3 weeks of age did not completely recover RORγt/FoxP3+ T reg cells or the <italic>Bacteriodes, Bacteriodes thetaiotaomicron</italic>, and <italic>Clostridi</italic>um XIVa numbers to D+ values. Early vitamin D status shapes the microbiota to optimize the population of colonic RORγt/FoxP3+ T reg cells important for resistance to colitis.</p>