Leptin brain entry via a tanycytic LepR-EGFR shuttle controls lipid metabolism and pancreas function.
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ABSTRACT:
SUBMITTER: Duquenne M
PROVIDER: S-EPMC7611554 | biostudies-literature | 2021 Aug
REPOSITORIES: biostudies-literature
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Leptin brain entry via a tanycytic LepR-EGFR shuttle controls lipid metabolism and pancreas function.
Duquenne Manon M Folgueira Cintia C Bourouh Cyril C Millet Marion M Silva Anisia A Clasadonte Jérôme J Imbernon Monica M Fernandois Daniela D Martinez-Corral Ines I Kusumakshi Soumya S Caron Emilie E Rasika S S Deliglia Eleonora E Jouy Nathalie N Oishi Asturo A Mazzone Massimiliano M Trinquet Eric E Tavernier Jan J Kim Young-Bum YB Ory Stéphane S Jockers Ralf R Schwaninger Markus M Boehm Ulrich U Nogueiras Ruben R Annicotte Jean-Sébastien JS Gasman Stéphane S Dam Julie J Prévot Vincent V
Nature metabolism 20210802 8
Metabolic health depends on the brain's ability to control food intake and nutrient use versus storage, processes that require peripheral signals such as the adipocyte-derived hormone, leptin, to cross brain barriers and mobilize regulatory circuits. We have previously shown that hypothalamic tanycytes shuttle leptin into the brain to reach target neurons. Here, using multiple complementary models, we show that tanycytes express functional leptin receptor (LepR), respond to leptin by triggering ...[more]
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Project description:Hypothalamic glial cells named tanycytes, which line the 3rd ventricle (3V), are components of the hypothalamic network that regulates a diverse array of metabolic functions for energy homeostasis. Herein, we report that TSPO (translocator protein), an outer mitochondrial protein, is highly enriched in tanycytes and regulates homeostatic responses to nutrient excess as a potential target for an effective intervention in obesity. Administration of a TSPO ligand, PK11195, into the 3V, and tanycyte-specific deletion of Tspo reduced food intake and elevated energy expenditure, leading to negative energy balance in a high-fat diet challenge. Ablation of tanycytic Tspo elicited AMPK-dependent lipophagy, breaking down lipid droplets into free fatty acids, thereby elevating ATP in a lipid stimulus. Our findings suggest that tanycytic TSPO affects systemic energy balance through macroautophagy/autophagy-regulated lipid metabolism, and highlight the physiological significance of TSPO in hypothalamic lipid sensing and bioenergetics in response to overnutrition.Abbreviations3V: 3rd ventricle; ACAC: acetyl-Coenzyme A carboxylase; AGRP: agouti related neuropeptide; AIF1/IBA1: allograft inflammatory factor 1; AMPK: AMP-activated protein kinase; ARC: arcuate nucleus; Atg: autophagy related; Bafilo: bafilomycin A1; CAMKK2: calcium/calmodulin-dependent protein kinase kinase 2, beta; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CNS: central nervous system; COX4I1: cytochrome c oxidase subunit 4I1; FFA: free fatty acid; GFAP: glial fibrillary acidic protein; HFD: high-fat diet; ICV: intracerebroventricular; LAMP2: lysosomal-associated membrane protein 2; LD: lipid droplet; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; MBH: mediobasal hypothalamus; ME: median eminence; MEF: mouse embryonic fibroblast; NCD: normal chow diet; NEFM/NFM: neurofilament medium; NPY: neuropeptide Y; OL: oleic acid; POMC: pro-opiomelanocortin-alpha; PRKN/Parkin: parkin RBR E3 ubiquitin protein ligase; Rax: retina and anterior neural fold homeobox; RBFOX3/NeuN: RNA binding protein, fox-1 homolog (C. elegans) 3; RER: respiratory exchange ratio; siRNA: small interfering RNA; SQSTM1: sequestosome 1; TG: triglyceride; TSPO: translocator protein; ULK1: unc-51 like kinase 1; VCO2: carbon dioxide production; VMH: ventromedial hypothalamus; VO2: oxygen consumption.
| S-EPMC7469491 | biostudies-literature
Project description:The autonomic nervous system plays a critical role in glucose metabolism through both its sympathetic and parasympathetic branches, but the mechanisms that underlie the development of the autonomic innervation of the pancreas remain poorly understood. Here, we report that cholinergic innervation of pancreatic islets develops during mid-gestation under the influence of leptin. Leptin-deficient mice display a greater cholinergic innervation of pancreatic islets beginning in embryonic life, and this increase persists into adulthood. Remarkably, a single intracerebroventricular injection of leptin in embryos caused a permanent reduction in parasympathetic innervation of pancreatic β cells and long-term impairments in glucose homeostasis. These developmental effects of leptin involve a direct inhibitory effect on the outgrowth of preganglionic axons from the hindbrain. These studies reveal an unanticipated regulatory role of leptin on the parasympathetic nervous system during embryonic development and may have important implications for our understanding of the early mechanisms that contribute to diabetes.
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Project description:Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Methods: Male ZDF rats at six week of age were randomly divided into two groups and administered testosterone undecanoate(TU) or vehicle alone every three days for three weeks. After three weeks, overnight fasted blood glucose and insulin concentrations were significantly higher and glucose tolerance and insulin sensitivity were impaired in TU treated ZDF rats compared to vehicle controls. Moreover, increased serum triglycerides and VLDL were observed in TU treated rats. To further explore the observed metabolic changes in TU treated ZDF rats, whole-genome microarray analysis were performed on isolated liver mRNA. Results: Array analysis revealed that many hepatic lipogenic genes were increased in male ZDF rat livers treated with TU. Interestingly, SREBP-1c, a key transcriptional activator of lipogenic genes and PGC-1 , an activator of SREBP-1c were induced while small heterodimer partner, a transcriptional inhibitor of lipogenic genes was suppressed by TU treatment. Exploring signaling pathways for these effects, we observed that the hepatic activated forms of STAT3 and AMPK, two known inhibitors of hepatic lipogenesis, were decreased in TU treated rat. Moreover, we observed that DHT could block the induction of STAT3 and AMPK phosphorylation in treated primary human hepatocytes. Preliminarily, in the leptin receptor positive zucker diabetic lean male rats, we observed that TU treatment has an oppose effect on the hepatic lipogenic genes, suggesting that hepatic leptin signaling may influence androgen signaling. Further insight into the relationship between androgen deficiency and the leptin system may help improve treatment of the metabolic syndrome. Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Two-condition experiment. (1) lean ZDF rats (control) vs. lean ZDF rats (testosterone treated). (2) obese ZDF rats (control) vs. obese ZDF rats (testosterone treated). Biological replicates: 4 control replicates, 4 treated replicates.
2012-09-02 | E-GEOD-23941 | biostudies-arrayexpress
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Project description:Perturbations in the functional integrity of the leptin axis are obvious candidates for mediation of altered adiposity. In a large number of genetic association studies in humans, the nonconservative LEPR Q223R allele has been inconsistently associated with adiposity. Subtle, long-term effects of such genetic variants can be obscured by effects of the environment and other confounders that render definitive inferences difficult to reach. We directly assessed the biological effects of this variant in 129P3/J mice segregating for the humanized Lepr allele at codon 223. No effects of this allele were detected on body weight, composition, or energy expenditure in animals fed diets of varying fat content over periods as long as 235 days. In vitro, Q223R did not affect leptin signaling as reflected by activation of STAT3. We conclude that Q223R is unlikely to play a significant role in regulation of human adiposity. This approach to vetting of human allelic variation might be more widely used.
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Project description:Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions. Methods: Male ZDF rats at six week of age were randomly divided into two groups and administered testosterone undecanoate(TU) or vehicle alone every three days for three weeks. After three weeks, overnight fasted blood glucose and insulin concentrations were significantly higher and glucose tolerance and insulin sensitivity were impaired in TU treated ZDF rats compared to vehicle controls. Moreover, increased serum triglycerides and VLDL were observed in TU treated rats. To further explore the observed metabolic changes in TU treated ZDF rats, whole-genome microarray analysis were performed on isolated liver mRNA. Results: Array analysis revealed that many hepatic lipogenic genes were increased in male ZDF rat livers treated with TU. Interestingly, SREBP-1c, a key transcriptional activator of lipogenic genes and PGC-1 , an activator of SREBP-1c were induced while small heterodimer partner, a transcriptional inhibitor of lipogenic genes was suppressed by TU treatment. Exploring signaling pathways for these effects, we observed that the hepatic activated forms of STAT3 and AMPK, two known inhibitors of hepatic lipogenesis, were decreased in TU treated rat. Moreover, we observed that DHT could block the induction of STAT3 and AMPK phosphorylation in treated primary human hepatocytes. Preliminarily, in the leptin receptor positive zucker diabetic lean male rats, we observed that TU treatment has an oppose effect on the hepatic lipogenic genes, suggesting that hepatic leptin signaling may influence androgen signaling. Further insight into the relationship between androgen deficiency and the leptin system may help improve treatment of the metabolic syndrome. Population based studies have established that androgen deficiency in males correlates with type 2 diabetes, visceral adiposity, and metabolic syndrome. Androgen therapy has been investigated as a possible treatment regime to combat these disorders. However, the molecular mechanism of androgen effects on these diseases still remain poorly understood. The zucker diabetic fatty (ZDF) rat, containing a mutation in the leptin receptor, is a well-investigated model of obesity and type 2 diabetes. Male rats are characterized as androgen deficient and spontaneously develop obese, hyperlipidemia, hyperglycemia and hyperinsulinemia. In this study, we used ZDF male rats as a model of metabolic syndrome to investigate the effects of testosterone administration on the development of the metabolic conditions.
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