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Science (New York, N.Y.) Aug 2023The intestinal microbiota regulates mammalian lipid absorption, metabolism, and storage. We report that the microbiota reprograms intestinal lipid metabolism in mice by...
The intestinal microbiota regulates mammalian lipid absorption, metabolism, and storage. We report that the microbiota reprograms intestinal lipid metabolism in mice by repressing the expression of long noncoding RNA (lncRNA) (small nucleolar RNA host gene 9) in small intestinal epithelial cells. suppressed the activity of peroxisome proliferator-activated receptor γ (PPARγ)-a central regulator of lipid metabolism-by dissociating the PPARγ inhibitor sirtuin 1 from cell cycle and apoptosis protein 2 (CCAR2). Forced expression of in the intestinal epithelium of conventional mice impaired lipid absorption, reduced body fat, and protected against diet-induced obesity. The microbiota repressed expression through an immune relay encompassing myeloid cells and group 3 innate lymphoid cells. Our findings thus identify an unanticipated role for a lncRNA in microbial control of host metabolism.
Topics: Animals; Mice; Gastrointestinal Microbiome; Immunity, Innate; Lipid Metabolism; Lymphocytes; PPAR gamma; RNA, Long Noncoding; Sirtuin 1; Cell Cycle Proteins; Apoptosis Regulatory Proteins; Myeloid Cells; Intestines; Adipose Tissue; Humans
PubMed: 37616368
DOI: 10.1126/science.ade0522 -
Nature Aug 2023Sympathetic activation during cold exposure increases adipocyte thermogenesis via the expression of mitochondrial protein uncoupling protein 1 (UCP1). The propensity of...
Sympathetic activation during cold exposure increases adipocyte thermogenesis via the expression of mitochondrial protein uncoupling protein 1 (UCP1). The propensity of adipocytes to express UCP1 is under a critical influence of the adipose microenvironment and varies between sexes and among various fat depots. Here we report that mammary gland ductal epithelial cells in the adipose niche regulate cold-induced adipocyte UCP1 expression in female mouse subcutaneous white adipose tissue (scWAT). Single-cell RNA sequencing shows that glandular luminal epithelium subtypes express transcripts that encode secretory factors controlling adipocyte UCP1 expression under cold conditions. We term these luminal epithelium secretory factors 'mammokines'. Using 3D visualization of whole-tissue immunofluorescence, we reveal sympathetic nerve-ductal contact points. We show that mammary ducts activated by sympathetic nerves limit adipocyte UCP1 expression via the mammokine lipocalin 2. In vivo and ex vivo ablation of mammary duct epithelium enhance the cold-induced adipocyte thermogenic gene programme in scWAT. Since the mammary duct network extends throughout most of the scWAT in female mice, females show markedly less scWAT UCP1 expression, fat oxidation, energy expenditure and subcutaneous fat mass loss compared with male mice, implicating sex-specific roles of mammokines in adipose thermogenesis. These results reveal a role of sympathetic nerve-activated glandular epithelium in adipocyte UCP1 expression and suggest that mammary duct luminal epithelium has an important role in controlling glandular adiposity.
Topics: Animals; Female; Male; Mice; Adipocytes; Adipose Tissue, White; Epithelium; Thermogenesis; Uncoupling Protein 1; Mammary Glands, Animal; Cold Temperature; Sympathetic Nervous System; Energy Metabolism; Oxidation-Reduction; Sex Characteristics
PubMed: 37495690
DOI: 10.1038/s41586-023-06361-5 -
Differentiation; Research in Biological... Nov 2023Fibroblast growth factor 20 (FGF20) is a neurotrophic factor and a member of the FGF9 subfamily. It was first identified in Xenopus embryos and was isolated shortly...
Fibroblast growth factor 20 (FGF20) is a neurotrophic factor and a member of the FGF9 subfamily. It was first identified in Xenopus embryos and was isolated shortly thereafter from the adult rat brain. Its receptors include FGFR4, FGFR3b, FGFR2b and the FGFRc splice forms. In adults it is highly expressed in the brain, while it is expressed in a variety of regions during embryonic development, including the inner ear, heart, hair placodes, mammary buds, dental epithelium and limbs. As a result of its wide-spread expression, FGF20 mouse mutants exhibit a variety of phenotypes including congenital deafness, lack of hair, small kidneys and delayed mammary ductal outgrowth. FGF20 is also associated with human diseases including Parkinson's Disease, cancer and hereditary deafness.
PubMed: 38007375
DOI: 10.1016/j.diff.2023.10.005 -
Nature Aug 2023Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development....
Recent studies have documented frequent evolution of clones carrying common cancer mutations in apparently normal tissues, which are implicated in cancer development. However, our knowledge is still missing with regard to what additional driver events take place in what order, before one or more of these clones in normal tissues ultimately evolve to cancer. Here, using phylogenetic analyses of multiple microdissected samples from both cancer and non-cancer lesions, we show unique evolutionary histories of breast cancers harbouring der(1;16), a common driver alteration found in roughly 20% of breast cancers. The approximate timing of early evolutionary events was estimated from the mutation rate measured in normal epithelial cells. In der(1;16)(+) cancers, the derivative chromosome was acquired from early puberty to late adolescence, followed by the emergence of a common ancestor by the patient's early 30s, from which both cancer and non-cancer clones evolved. Replacing the pre-existing mammary epithelium in the following years, these clones occupied a large area within the premenopausal breast tissues by the time of cancer diagnosis. Evolution of multiple independent cancer founders from the non-cancer ancestors was common, contributing to intratumour heterogeneity. The number of driver events did not correlate with histology, suggesting the role of local microenvironments and/or epigenetic driver events. A similar evolutionary pattern was also observed in another case evolving from an AKT1-mutated founder. Taken together, our findings provide new insight into how breast cancer evolves.
Topics: Adolescent; Adult; Female; Humans; Young Adult; Breast Neoplasms; Cell Lineage; Clone Cells; Epigenesis, Genetic; Epithelial Cells; Epithelium; Evolution, Molecular; Microdissection; Mutagenesis; Mutation; Mutation Rate; Premenopause; Tumor Microenvironment
PubMed: 37495687
DOI: 10.1038/s41586-023-06333-9 -
Cardiovascular Research Oct 2023Enhancing SIRT1 activity exerts beneficial cardiovascular effects. In diabetes, plasma SIRT1 levels are reduced. We aimed to investigate the therapeutic potential of...
AIMS
Enhancing SIRT1 activity exerts beneficial cardiovascular effects. In diabetes, plasma SIRT1 levels are reduced. We aimed to investigate the therapeutic potential of chronic recombinant murine SIRT1 (rmSIRT1) supplementation to alleviate endothelial and vascular dysfunction in diabetic mice (db/db).
METHODS AND RESULTS
Left internal mammary arteries obtained from patients undergoing coronary artery bypass grafting with or without a diagnosis of diabetes were assayed for SIRT1 protein levels. Twelve-week-old male db/db mice and db/+ controls were treated with vehicle or rmSIRT1 intraperitoneally for 4 weeks, after which carotid artery pulse wave velocity (PWV) and energy expenditure/activity were assessed by ultrasound and metabolic cages, respectively. Aorta, carotid, and mesenteric arteries were isolated to determine endothelial and vascular function using the myograph system.Arteries obtained from diabetic patients had significantly lower levels of SIRT1 relative to non-diabetics. In line, aortic SIRT1 levels were reduced in db/db mice compared to db/+ mice, while rmSIRT1 supplementation restored SIRT1 levels. Mice receiving rmSIRT1 supplementation displayed increased physical activity and improved vascular compliance as reflected by reduced PWV and attenuated collagen deposition. Aorta of rmSIRT1-treated mice exhibited increased endothelial nitric oxide (eNOS) activity, while endothelium-dependent contractions of their carotid arteries were significantly decreased, with mesenteric resistance arteries showing preserved hyperpolarization. Ex vivo incubation with reactive oxygen species (ROS) scavenger Tiron and NADPH oxidase inhibitor apocynin revealed that rmSIRT1 leads to preserved vascular function by suppressing NADPH oxidase (NOX)-related ROS synthesis. Chronic rmSIRT1 treatment resulted in reduced expression of both NOX1 and NOX4, in line with a reduction in aortic protein carbonylation and plasma nitrotyrosine levels.
CONCLUSIONS
In diabetic conditions, arterial SIRT1 levels are significantly reduced. Chronic rmSIRT1 supplementation improves endothelial function and vascular compliance by enhancing eNOS activity and suppressing NOX-related oxidative stress. Thus, SIRT1 supplementation may represent novel therapeutic strategy to prevent diabetic vascular disease.
Topics: Humans; Mice; Male; Animals; Reactive Oxygen Species; Diabetes Mellitus, Experimental; Vasodilation; Sirtuin 1; Pulse Wave Analysis; Endothelium, Vascular; Oxidative Stress; NADPH Oxidases; Dietary Supplements; Mice, Inbred C57BL; Nitric Oxide Synthase Type III
PubMed: 37401647
DOI: 10.1093/cvr/cvad102