The epidermal barrier defends the body against dehydration and harmful substances. The commensal microbiota is essential for proper differentiation and repair of the epidermal barrier, an effect mediated by the aryl hydrocarbon receptor (AHR). However, the microbial mechanisms of AHR activation in skin are less understood. Tryptophan metabolites are AHR ligands that can be products of microbial metabolism. To identify microbially regulated tryptophan metabolites in vivo, we established a gnotobiotic model colonized with fifty human skin commensals and performed targeted mass spectrometry on murine skin. Indole-related metabolites were enriched in colonized skin compared to germ-free skin. In reconstructed human epidermis and in murine models of atopic-like barrier damage, these metabolites improved barrier repair and function individually and as a cocktail. These results provide a framework for the identification of microbial metabolites that mediate specific host functions, which can guide the development of microbe-based therapies for skin disorders.
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http://dx.doi.org/10.1016/j.chembiol.2024.12.007 | DOI Listing |
Microb Pathog
January 2025
State Key Laboratory of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong, China; Guangzhou National Laboratory, Guangzhou, Guangdong, China. Electronic address:
Background: The coexistence of tuberculosis (TB) and lung cancer (LC) is not rare, but their causal association are underexplored. This study aims to elucidate these bidirectional correlations and investigate the mediating effects of immunophenotypes and plasma metabolites.
Methods: Genetic variants for TB and LC were sourced from the IEU Open GWAS Project, while data for 731 immunophenotypes and 1400 plasma metabolites from previously published GWAS.
J Biol Chem
January 2025
Department of Chemistry, The University of Texas at San Antonio, Texas 78249, United States. Electronic address:
MarE, a heme-dependent enzyme, catalyzes a unique 2-oxindole-forming monooxygenation reaction from tryptophan metabolites. To elucidate its enzyme-substrate interaction mode, we present the first X-ray crystal structures of MarE in complex with its prime substrate, (2S,3S)-β-methyl-L-tryptophan and cyanide at 1.89 Å resolution as well as a truncated yet catalytically active version in complex with the substrate at 2.
View Article and Find Full Text PDFmBio
January 2025
Centre for Microbiology and Environmental Systems Science, Department of Microbiology and Ecosystem Science, Division of Microbial Ecology, University of Vienna, Vienna, Austria.
Unlabelled: In the gut, microRNAs (miRNAs) produced by intestinal epithelial cells are secreted into the lumen and can shape the composition and function of the gut microbiome. Crosstalk between gut microbes and the host plays a key role in irritable bowel syndrome (IBS) and inflammatory bowel diseases, yet little is known about how the miRNA-gut microbiome axis contributes to the pathogenesis of these conditions. Here, we investigate the ability of miR-21, a miRNA that we found decreased in fecal samples from IBS patients, to associate with and regulate gut microbiome function.
View Article and Find Full Text PDFMol Neurobiol
January 2025
Cellular and Molecular Neurobiology and Drug Targeting Laboratory, Department of Zoology, Indira Gandhi National Tribal University, Amarkantak-484 887, MP, India.
Depression is one of the most disabling mental disorders worldwide and characterized by symptoms including worthlessness, anhedonia, sleep, and appetite disturbances. Recently, studies have suggested that tryptophan (Trp) metabolism plays a key role in depressed mood through serotonin and kynurenine pathway involving enzyme tryptophan 5-monooxygenase (TPH) and indoleamine-2,3-dioxygenase (IDO) respectively. Moreover, during neuroinflammation, IDO is activated by proinflammatory cytokines and affects neurogenesis, cognition, disturbed hypothalamic-pituitary-adrenal (HPA) axis, and gut homeostasis by altering the gut bacteria and its metabolites like Trp derivatives.
View Article and Find Full Text PDFFront Pharmacol
January 2025
Department of Pharmacognosy, School of Pharmacy, Xinjiang Medical University, Urumqi, China.
Objective: To elucidate the metabolic mechanisms by which acteoside (ACT) isolated from alleviates cancer-related fatigue (CRF) in a murine model of colon cancer with cachexia.
Methods: BALB/c mice inoculated with C26 colon cancer cells were treated with paclitaxel (PTX, 10 mg/kg) and ACT (100 mg/kg) alone or in combination for 21 days. Fatigue-associated behaviors, tumor inhibition rate, and skeletal muscle morphology assessed by hematoxylin-eosin (H&E) staining and electron microscopy were evaluated.
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