Neuro-mesenchyme units control ILC2 and obesity via a brain-adipose circuit [GAT MSCs]
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ABSTRACT: Signals from sympathetic neurons and immune cells regulate adipocytes contributing to fat tissue biology. Interactions between the nervous and immune systems have recently emerged as major regulators of host defence and inflammation1-4. Nevertheless, whether neuronal and immune cells cooperate in brain-body axes to orchestrate metabolism and obesity remains elusive. Here we report a novel neuro-mesenchyme unit that controls group 2 innate lymphoid cells (ILC2), adipose tissue physiology, metabolism and obesity via a brain-adipose circuit. We found that sympathetic nerve terminals act on neighbouring adipose mesenchymal cells via the beta-2 adrenergic receptor to control the expression of the glial-derived neurotrophic factor (GDNF) and the activity of ILC2 in gonadal fat. Accordingly, ILC2-autonomous manipulation of the GDNF receptor machinery led to altered ILC2 function, energy expenditure, insulin resistance and propensity to obesity. Retrograde tracing, chemical, surgical and chemogenetic manipulations identified a sympathetic aorticorenal circuit that modulates gonadal fat ILC2 and connects to high-order brain areas, including the paraventricular nucleus of the hypothalamus (PVH). Our work decodes a neuro-mesenchymal unit that translates long-range neuronal circuitry cues into adipose-resident ILC2 function, shaping the host metabolism and obesity.
Project description:Signals from sympathetic neurons and immune cells regulate adipocytes contributing to fat tissue biology. Interactions between the nervous and immune systems have recently emerged as major regulators of host defence and inflammation1-4. Nevertheless, whether neuronal and immune cells cooperate in brain-body axes to orchestrate metabolism and obesity remains elusive. Here we report a novel neuro-mesenchyme unit that controls group 2 innate lymphoid cells (ILC2), adipose tissue physiology, metabolism and obesity via a brain-adipose circuit. We found that sympathetic nerve terminals act on neighbouring adipose mesenchymal cells via the beta-2 adrenergic receptor to control the expression of the glial-derived neurotrophic factor (GDNF) and the activity of ILC2 in gonadal fat. Accordingly, ILC2-autonomous manipulation of the GDNF receptor machinery led to altered ILC2 function, energy expenditure, insulin resistance and propensity to obesity. Retrograde tracing, chemical, surgical and chemogenetic manipulations identified a sympathetic aorticorenal circuit that modulates gonadal fat ILC2 and connects to high-order brain areas, including the paraventricular nucleus of the hypothalamus (PVH). Our work decodes a neuro-mesenchymal unit that translates long-range neuronal circuitry cues into adipose-resident ILC2 function, shaping the host metabolism and obesity.
Project description:The melanocortin system is a brain circuit that influences energy balance by regulating energy intake and expenditure. In addition, the brain-melanocortin system controls adipose tissue metabolism to optimize fuel mobilization and storage. Specifically, increased brain-melanocortin signaling or negative energy balance promotes lipid mobilization by increasing Sympathetic Nervous input to adipose tissue. In contrast, calorie-independent mechanisms favoring energy storage are less understood. Here we demonstrate that obesogenic signals, including reduction of brain-melanocortin signaling or high-fat feeding, actively promote fat mass gain independently of caloric intake via efferent nerve fibers conveyed by the common hepatic branch of the vagus nerve. These signals promote adipose tissue expansion by activating lipogenic program and adipocyte and endothelial cell proliferation independently of insulin action or the sympathetic tone to adipose tissue. These data reveal a novel physiological mechanism whereby the brain controls energy stores that may contribute to increased susceptibility to obesity.
Project description:Activation of brown fat thermogenesis increases energy expenditure and alleviates obesity. Sympathetic nervous system (SNS) is important in brown/beige adipocyte thermogenesis. Here we discover a novel fat-derived “adipokine” neurotrophic factor neurotrophin 3 (NTF3) and its receptor Tropomyosin receptor kinase C (TRKC) as key regulators of SNS growth and innervation in adipose tissue. NTF3 is highly expressed in brown/beige adipocytes, and potently stimulates sympathetic neuron neurite growth. NTF3/TRKC regulates a plethora of pathways in neuronal axonal growth and elongation. Adipose tissue sympathetic innervation is significantly increased in mice with adipocyte-specific NTF3 overexpression, but profoundly reduced in mice with TRKC haploinsufficiency (TRKC+/-). Increasing NTF3 via pharmacological or genetic approach promotes beige adipocyte development, enhances cold-induced thermogenesis and protects against diet-induced obesity (DIO); whereas TRKC+/- mice or SNS TRKC deficient mice are cold intolerant and prone to DIO. Thus, NTF3 is an important fat-derived neurotrophic factor regulating SNS innervation, energy metabolism and obesity.
Project description:Transcript abundance in adipose and liver tissues was used to map expression quantitative trait loci (eQTL) underlying fat accretion, weight gain and liver weight. Gonadal fat and liver tissues were used from 48 individuals F2 selected from a cohort (1,200 mice) originated from a cross between M16i and MB2 mice. A complex polygenic architecture within the MB2 locus was observed which was comprised of several locally regulated eQTL (cis-eQTL) with significant correlations to obesity traits. Total RNA obtained from isolated gonadal fat and liver tissues were used to mesured transcript abundance in order to detect expression QTLs.
Project description:Identify genes in the gonadal adipose tissue whose expression is under genetic regulation in the Hybrid Mouse Diversity Panel (HMDP). The HMDP comprises classical inbred and recombinant inbred wild type mice. The RMA values of genes were used for genome wide association as described in Parks et al Cell Metabolism 2015. These data are used to identify candidate genes at loci associated with obesity and dietary responsiveness. GWAS for expression of gonadal adipose tissue in inbred strains fed chow diet for 8 weeks followed by high-fat/high-sucrose diet 8 weeks
Project description:Adipose tissues (ATs) are innervated by sympathetic nerves, which drive reduction of fat mass via lipolysis and thermogenesis. Here, we report a population of immunomodulatory leptin receptor (LepR)-expressing barrier cells which ensheath sympathetic axon bundles in adipose tissues. These LepR-expressing Sympathetic Perineurial Cells (SPCs) produce IL33, a factor for maintenance and recruitment of regulatory T cell (Treg) and eosinophils in AT. Brown adipose tissues (BAT) of mice lacking IL33 in SPCs (SPCIL33cKO) have fewer Treg and eosinophils, resulting in increased BAT inflammation. These SPCIL33cKO mice are more susceptible to diet-induced obesity, independently of food intake. Furthermore, SPCIL33cKO mice have impaired adaptive thermogenesis, and are unresponsive to leptin-induced rescue of metabolic adaptation. We, therefore, identify LepR-expressing SPCs as a source of IL33 which orchestrate an anti-inflammatory environment in BAT, preserving sympathetic-mediated thermogenesis and body weight homeostasis. LepR+ IL33+SPCs provide a cellular link between leptin and immune regulation of body weight, unifying neuroendocrinology and immunometabolism as previously disconnected fields of obesity research.
Project description:Glycyrrhetinic acid (GA) and its derivative, magnesium isoglycyrrhizinate, exhibit promising anti-obesity effects through mechanisms that are not fully understood. Here, we showed that GA mitigated white adipose tissue remodeling and diet-induced obesity by enhancing lipid catabolism. GA indirectly promoted adipocyte lipolysis and thermogenesis by modulating catecholamine pathways, facilitated by increased intra-fat sympathetic innervation and reduced protein expression of monoamine oxidase A (MAOA), which degrades norepinephrine. In suit visualization of MAOA identified adipose tissue macrophages (ATMs) as key mediators of intra-fat catecholamine degradation. RNA sequencing of sorted ATMs revealed that GA reduced pro-inflammatory shifts and altered macrophage polarity, preventing activation of the Toll-like receptor 4 (TLR4) signaling pathway, as supported by molecular docking analysis and binding assays. Moreover, the anti-obesity effects of GA were absent in TLR4-deletive mice, which exhibited decreased MAOA protein levels and sensitivity to FUNDC1-mediated mitophagy in ATMs. These findings suggest that GA targets macrophage-sympathetic neuron crosstalk, offering a promising therapeutic approach for obesity by preserving NE availability and promoting lipid catabolism.