Hooper, L. V. | bioRxiv Science

bioRxiv2019

The intestinal microbiota programs diurnal rhythms in host metabolism through histone deacetylase 3

Circadian rhythmicity is a defining feature of mammalian metabolism that synchronizes metabolic processes to day-night light cycles. Here, we show that the intestinal microbiota programs diurnal metabolic rhythms in the mouse small intestine through histone deacetylase 3 (HDAC3). The microbiota induced expression of intestinal epithelial HDAC3, which was recruited rhythmically to chromatin and produced synchronized diurnal oscillations in histone acetylation, metabolic gene expression, and nutrient uptake. HDAC3 also functioned non-canonically to coactivate estrogen related receptor (ERR), inducing microbiota-dependent rhythmic transcription of the lipid transporter gene Cd36 and promoting lipid absorption and diet-and jet lag-induced obesity. Our findings reveal that HDAC3 integrates microbial and circadian cues to regulate diurnal metabolic rhythms, and pinpoint a key mechanism by which the microbiota controls host metabolism. One sentence summaryThe intestinal microbiota induces daily metabolic rhythms and controls lipid uptake through the enzyme histone deacetylase 3.

microbiology↗

bioRxiv2019

Epithelial retinoid acid receptor β regulates serum amyloid A expression and vitamin A-dependent intestinal immunity

Vitamin A is a dietary component that is essential for the development of intestinal immunity. Vitamin A is absorbed and converted to its bioactive derivatives retinol and retinoic acid by the intestinal epithelium, yet little is known about how epithelial cells regulate vitamin A-dependent intestinal immunity. Here we show that epithelial cell expression of the transcription factor retinoic acid receptor {beta} (RAR{beta}) is essential for vitamin A-dependent intestinal immunity. Epithelial RAR{beta} activated vitamin A-dependent expression of serum amyloid A (SAA) proteins by binding directly to Saa promoters. In accordance with the known role of SAAs in regulating Th17 cell effector function, epithelial RAR{beta} promoted IL-17 production by intestinal Th17 cells. More broadly, epithelial RAR{beta} was required for the development of key vitamin A-dependent adaptive immune responses, including CD4+ T cell homing to the intestine and the development of immunoglobulin A-producing intestinal B cells. Our findings provide insight into how the intestinal epithelium senses dietary vitamin A status to regulate adaptive immunity and highlight the role of epithelial cells in regulating intestinal immunity in response to diet. Significance StatementVitamin A is a nutrient that is essential for the development of intestinal immunity. It is absorbed by gut epithelial cells which convert it to retinol and retinoic acid. Here we show that the transcription factor retinoic acid receptor {beta} (RAR{beta}) allows epithelial cells to sense vitamin A in the diet and regulate vitamin A-dependent immunity in the intestine. We find that epithelial RAR{beta} regulates several intestinal immune responses, including production of the immunomodulatory protein serum amyloid A, T cell homing to the intestine, and B cell production of immunoglobulin A. Our findings provide new insight into how epithelial cells sense vitamin A to regulate intestinal immunity and highlight why vitamin A is so important for immunity to infection.

immunology↗