Protein kinase D1 deletion in adipocytes enhances energy dissipation and protects against adiposity
Ontology highlight
ABSTRACT: DAG-activated Pkd1 promotes triglyceride accumulation in adipocytes; Pkd1 promotes lipogenesis and suppresses mitochondrial function in adipocytes in an AMPK-dependent manner; Pkd1 suppresses expression of genes characteristic for beige adipocytes; Deletion of Pkd1 in adipocytes protects mice from diet-induced obesity, T2D and liver steatosis.
Project description:Beige adipocytes accumulates mitochondria and alleviates metabolic disorder via activating energy expenditure. Whether the opposing process of mitochondrial biogenesis and clearance are integrated regulated in beige adipocytes is beyond known. Here we show that DNA binding protein Ets1 suppresses beige adipocyte formation via bidirectional regulation of mitochondrial biogenesis and clearance. The expression level of Ets1 was down-regulated in browning adipocytes, and up-regulated in the subcutaneous fat of obese mice. Adipocyte Ets1 heterozygous knock-in mice showed suppressed beige adipocytes formation under cold stress, while the homozygous knock-in mice are cold intolerance. On the other hand, knocking out Ets1 in adipocytes enhanced energy expenditure and protect the mice from high fat diet induced metabolic disorders. Mechanical assay suggests Ets1 binds to the promoter region of mitochondria complex coding genes and autophagy related genes, transcriptionally suppresses mitochondrial biogenesis and activates its clearance. Our results indicate that Ets1 integrally regulates the balance of mitochondria generation and degradation, hence acts as a pivotal governor of mitochondria content and negatively regulates beige adipocyte formation.
Project description:Beige adipocytes accumulates mitochondria and alleviates metabolic disorder via activating energy expenditure. Whether the opposing process of mitochondrial biogenesis and clearance are integrated regulated in beige adipocytes is beyond known. Here we show that DNA binding protein Ets1 suppresses beige adipocyte formation via bidirectional regulation of mitochondrial biogenesis and clearance. The expression level of Ets1 was down-regulated in browning adipocytes, and up-regulated in the subcutaneous fat of obese mice. Adipocyte Ets1 heterozygous knock-in mice showed suppressed beige adipocytes formation under cold stress, while the homozygous knock-in mice are cold intolerance. On the other hand, knocking out Ets1 in adipocytes enhanced energy expenditure and protect the mice from high fat diet induced metabolic disorders. Mechanical assay suggests Ets1 binds to the promoter region of mitochondria complex coding genes and autophagy related genes, transcriptionally suppresses mitochondrial biogenesis and activates its clearance. Our results indicate that Ets1 integrally regulates the balance of mitochondria generation and degradation, hence acts as a pivotal governor of mitochondria content and negatively regulates beige adipocyte formation.
Project description:Here we show that synthesis of the mitochondrial phospholipid cardiolipin is an indispensable driver of thermogenic fat function. Cardiolipin biosynthesis is robustly induced in brown and beige adipose upon cold exposure. Mimicking this response by overexpressing cardiolipin synthase (Crls1) enhances energy consumption in mouse and human adipocytes. Crls1 deficiency diminishes mitochondrial uncoupling in brown and beige adipocytes and elicits a nuclear transcriptional response through ER stress-mediated retrograde communication. Cardiolipin depletion in brown and beige fat abolishes adipose thermogenesis and glucose uptake and renders animals strikingly insulin resistant. We further identify a rare human CRLS1 variant associated with insulin resistance and show that adipose CRLS1 levels positively correlate with insulin sensitivity. Thus, adipose cardiolipin is a powerful regulator of organismal energy homeostasis through thermogenic fat bioenergetics.
Project description:In Crohn’s disease (CD), microbe-host interactions are altered, with changes in microbial’s communities and barrier defects leading to translocation of microbes to surrounding adipose tissue (AT). We evaluated the presence of beige AT depots in CD and questioned whether succinate and/or bacterial translocation promotes white-to-beige transition in adipocytes.
Project description:Members of the Protein Kinase D (PKD) family (PKD1, 2, and 3) integrate hormonal and nutritional inputs to regulate complex cellular metabolism. Despite the fact that a number of functions have been annotated to particular PKDs, their molecular targets are relatively poorly explored. PKD3 promotes insulin sensitivity and suppresses lipogenesis in the liver of animals fed a high-fat diet. However, its substrates are largely unknown. Here we applied proteomic approaches to determine PKD3 targets. We identified over three-hundred putative targets of PKD3. Further, biochemical analysis revealed that PKD3 regulates cAMP-dependent protein kinase A (PKA) activity, a master regulator of the hepatic response to glucagon and fasting. PKA regulates glucose, lipid, and amino acid metabolism in the liver, by targeting key enzymes in the respective processes. Among them the PKA targets phenylalanine hydroxylase (PAH) catalyzes the conversion of phenylalanine to tyrosine Consistently, we showed that PKD3 is activated by glucagon and promotes glucose and tyrosine levels in hepatocytes
Project description:Prolonged cold exposure stimulates the recruitment of beige adipocytes within white adipose tissue. Beige adipocytes depend on mitochondrial oxidative phosphorylation to drive thermogenesis. The transcriptional mechanisms that promote remodeling in adipose tissue during the cold are not well understood. Here we demonstrate that the transcriptional coregulator transducin-like enhancer of split 3 (TLE3) inhibits mitochondrial gene expression in beige adipocytes. Conditional deletion of TLE3 in adipocytes promotes mitochondrial oxidative metabolism and increases energy expenditure, thereby improving glucose control. Using chromatin immunoprecipitation and deep sequencing, we found that TLE3 occupies distal enhancers in proximity to nuclear-encoded mitochondrial genes and that many of these binding sites are also enriched for early B-cell factor (EBF) transcription factors. TLE3 interacts with EBF2 and blocks its ability to promote the thermogenic transcriptional program. Collectively, these studies demonstrate that TLE3 regulates thermogenic gene expression in beige adipocytes through inhibition of EBF2 transcriptional activity. Inhibition of TLE3 may provide a novel therapeutic approach for obesity and diabetes.
Project description:Beige adipocytes are a distinct type of thermogenic fat cells in human. Since beige adipocytes are distributed sporadically within white adipose, characterization of human beige adipocytes has long been a problem. In this study, we reported a rapid and roboust method in generating human beige adipocyte with chemically defined medium and RNA-Seq was perfomed to reveal the molecular characterization of derived human beige adipocytes.
Project description:Low-protein/high carbohydrate (LP/HC) diet promotes metabolic health and longevity in adult human and animal models. However, the complex molecular underpinnings of how LP/HC diet leads to metabolic benefits remain elusive. Through a multi-layered approach, here we observed that LP/HC diet promotes an energy-dissipating response consisting in the parallel recruitment of canonical and non-canonical (muscular) thermogenic systems in subcutaneous adipose tissue (sWAT). In particular, we measured Ucp1 induction in association with up-regulation of actomyosin components and several Serca (Serca1, Serca2a, Serca2b) ATPases. In beige adipocytes, we observed that AMPK activation is responsible for transducing the amino acid lowering in an enhanced fat catabolism, which sustains both Ucp1- and Serca-dependent energy dissipation. Limiting AMPK activation counteracts the expression of brown fat and muscular genes, including Ucp1 and Serca, as well as mitochondrial oxidative genes. We observed that mitochondrial reactive oxygen species are the upstream molecules controlling AMPK-mediated metabolic rewiring in amino acid-restricted beige adipocytes. Our findings delineate a novel metabolic phenotype of responses to amino acid shortage, which recapitulates some of the benefits of cool temperature in sWAT. In conclusion, this study highlights LP/HC diet as a valuable and practicable strategy to prevent metabolic diseases through the enhancement of mitochondrial oxidative metabolism and the recruitment of different energy dissipating routes in beige adipocytes.
Project description:Prolonged cold exposure stimulates the recruitment of beige adipocytes within white adipose tissue. Beige adipocytes depend on mitochondrial oxidative phosphorylation to drive thermogenesis. The transcriptional coregulator TLE3 inhibits mitochondrial and metabolic gene expression in beige adipocytes.