Project description:The molecular mechanisms by which dietary fruits and vegetables confer cardiometabolic benefits remain poorly understood. Historically, these beneficial properties have been attributed to the antioxidant activity of flavonoids. Here, we reveal that the host metabolic benefits associated with flavonoid consumption actually hinge on gut microbial metabolism. However, flavonoids are consumed in a largely glycosylated form, rendering them poorly available for small intestinal absorption and subjecting them to microbial metabolism in the colon. We show that a single gut microbial flavonoid catabolite is sufficient to reduce diet-induced cardiometabolic disease burden in mice. Dietary supplementation with elderberry extract attenuated obesity and continuous delivery of the catabolite 4-hydroxphenylacetic acid was sufficient to reverse hepatic steatosis. Analysis of human gut metagenomes revealed that under one percent contains a flavonol catabolic pathway, underscoring the rarity of this process. Our study will impact the design of dietary and probiotic interventions to complement traditional cardiometabolic treatment strategies.
Project description:The maintenance of tissue-specific chronic inflammation results from the interplay of genetic and unidentified environmental factors. Here, we describe an immunoregulatory role for an environmentally driven microbial metabolite in Card14E138A/+-induced spontaneous psoriasis. Through metabolite screening, we demonstrate chronic skin inflammation is accompanied by alterations microbial metabolite. Notably, depletion of gut, not skin, microbes alleviates disease symptoms. We further identify indoxyl sulfate (I3S), a bacteriogenic metabolite, as a key driver of psoriatic inflammation and confirm that gut-resident indole-producing microbiota mediate this process. Mechanistically, indole-producing microbiota promote host I3S biothsynthesis via a metabolic relay, and I3S potentiates skin inflammation by reshaping chromatin accessibility in skin Th17 cells through AHR signaling. In human psoriasis cohorts, serum I3S levels correlate with disease severit. In summary, our study uncovers a mechanistic link between gut microbial factors and type 3 skin inflammation, highlighting targeting gut microbiota as a strategy for mitigating skin inflammation.
Project description:The maintenance of tissue-specific chronic inflammation results from the interplay of genetic and unidentified environmental factors. Here, we describe an immunoregulatory role for an environmentally driven microbial metabolite in Card14E138A/+-induced spontaneous psoriasis. Through metabolite screening, we demonstrate chronic skin inflammation is accompanied by alterations microbial metabolite. Notably, depletion of gut, not skin, microbes alleviates disease symptoms. We further identify indoxyl sulfate (I3S), a bacteriogenic metabolite, as a key driver of psoriatic inflammation and confirm that gut-resident indole-producing microbiota mediate this process. Mechanistically, indole-producing microbiota promote host I3S biothsynthesis via a metabolic relay, and I3S potentiates skin inflammation by reshaping chromatin accessibility in skin Th17 cells through AHR signaling. In human psoriasis cohorts, serum I3S levels correlate with disease severit. In summary, our study uncovers a mechanistic link between gut microbial factors and type 3 skin inflammation, highlighting targeting gut microbiota as a strategy for mitigating skin inflammation.
Project description:Reprogramming in vivo using OCT4, SOX2, KLF4 and MYC (OSKM) triggers cell dedifferentiation, which is considered of relevance for tissue repair and regeneration. However, little is known about the metabolic requirements of this process. We found that antibiotic depletion of the gut microbiota abolished in vivo reprogramming. Analysis of bacterial metagenomes from stool samples of wild type (WT) and OSKM mice treated with doxycycline led us to identify vitamin B12 as a key factor for in vivo reprogramming, which is partly supplied by the microbiome. We report that B12 demand increases during reprogramming due to enhanced expression of enzymes in the methionine cycle, and supplementing B12 levels both in vitro and in vivo enhances the efficiency of OSKM reprogramming.