Project description:The prevalence of overweight and obesity continues to rise in the population worldwide. Because it is an important predisposing factor for cancer, cardiovascular diseases, diabetes mellitus, and COVID-19, obesity reduces life expectancy. Adipose tissue (AT), the main fat storage organ with endocrine capacity, plays fundamental roles in systemic metabolism and obesity-related diseases. Dysfunctional AT can induce excess or reduced body fat (lipodystrophy). Dido1 is a marker gene for stemness; gene-targeting experiments compromised several functions ranging from cell division to embryonic stem cell differentiation, both in vivo and in vitro. We report that mutant mice lacking the DIDO N terminus show a lean phenotype. This consists of reduced AT and hypolipidemia, even when mice are fed a high-nutrient diet. DIDO mutation caused hypothermia due to lipoatrophy of white adipose tissue (WAT) and dermal fat thinning. Deep sequencing of the epididymal white fat (Epi WAT) transcriptome supported Dido1 control of the cellular lipid metabolic process. We found that, by controlling the expression of transcription factors such as C/EBPα or PPARγ, Dido1 is necessary for adipocyte differentiation, and that restoring their expression reestablished adipogenesis capacity in Dido1 mutants. Our model differs from other lipodystrophic mice and could constitute a new system for the development of therapeutic intervention in obesity.
Project description:The prevalence of overweight and obesity continues to rise in the population worldwide. Because it is an important predisposing factor for cancer, cardiovascular diseases, diabetes mellitus, and COVID-19, obesity reduces life expectancy. Adipose tissue (AT), the main fat storage organ with endocrine capacity, plays fundamental roles in systemic metabolism and obesity-related diseases. Dysfunctional AT can induce excess or reduced body fat (lipodystrophy). Dido1 is a marker gene for stemness; gene-targeting experiments compromised several functions ranging from cell division to embryonic stem cell differentiation, both in vivo and in vitro. We report that mutant mice lacking the DIDO N terminus show a lean phenotype. This consists of reduced AT and hypolipidemia, even when mice are fed a high nutrient diet. DIDO mutation caused hypothermia due to lipoatrophy of white adipose tissue (WAT) and dermal fat thinning. Deep sequencing of the epididymal white fat (Epi WAT) transcriptome supported Dido1 control of the lipid metabolic process. We found that, by controlling expression of transcription factors such as C/EBPα or PPARγ, Dido1 is necessary for adipocyte differentiation, and that restoring their expression reestablished adipogenesis capacity in Dido1 mutants. Our model differs from other lipodystrophic mice and could constitute a new system for the development of therapeutic intervention in obesity.
Project description:Rates of overweight and obesity continue to rise in the population worldwide. Obesity reduces life expectancy because it is an important predisposing factor for cancer, cardiovascular diseases and diabetes mellitus. Adipose tissue (AT), the main organ for fat storage with endocrine capacity, plays fundamental roles in systemic metabolism and in obesity-related diseases. Adiposity and lipodystrophy are associated with metabolic disorders, indicating that normal AT function is required for metabolic health. Dido1 is a marker gene for stemness and gene-targeting experiments compromised several functions from cell division to embryonic stem cell differentiation, in vivo and in vitro. Using animals carrying a DIDO mutant without the N-terminal, we report that these mice display a lean phenotype with reduced adipose tissue and hypolipidemia even when fed with an obesogenic diet. The phenotype related to impaired adipogenesis, partially corrected by transcription factors C/EBPα or PPARγ expression and to hypothermia subsequent to dermal fat thinning. Deep sequencing of the epididymal white fat (Epi WAT) transcriptome shows the role of Dido1 in the control of cellular lipases. The molecular analysis involves Dido1 in orchestrating adipogenesis and altogether offers a model different from described lipodystrophies in mice and pioneers a new path to understand obesity and identify mechanism for obesity intervention.
Project description:An understanding of the mechanisms regulating white adipose tissue (WAT) formation is key for developing of new tools to treat obesity and its related diseases. Here, we identify DEPTOR as a positive regulator of adipogenesis whose expression is associated with obesity. In a polygenic mouse model of obesity/leanness, Deptor is part of the Fob3a QTL linked to obesity and we fine that Deptor is the highest priority candidate gene regulating WAT accumulation in this model. Using a doxycycline-inducible mouse model for Deptor overexpression, we confirmed that Deptor promotes WAT expansion in vivo. DEPTOR expression is elevated in WAT of obese humans and strongly correlates with the degree of obesity. We show that DEPTOR is induced during adipogenesis and that its overexpression cell-autonomously promotes, while its suppression blocks, adipogenesis. DEPTOR positively regulates adipogenesis by promoting the activity of the pro-adipogenic factors Akt/PKB and PPAR-gamma. These results establish DEPTOR as a physiological regulator of adipogenesis and provide new insights into the molecular mechanisms controlling WAT formation. 2 groups of F2 mice for opossing genotype at Fob3a QTL (FF versus VV) - parental strains of the F2 cross were the Fat line and congenic V-line; 5 biological replications per group; reference for Fat line: Horvat S. et al. (2000) MAMMALIAN GENOME 11(1): 2-7
Project description:An understanding of the mechanisms regulating white adipose tissue (WAT) formation is key for developing of new tools to treat obesity and its related diseases. Here, we identify DEPTOR as a positive regulator of adipogenesis whose expression is associated with obesity. In a polygenic mouse model of obesity/leanness, Deptor is part of the Fob3a QTL linked to obesity and we fine that Deptor is the highest priority candidate gene regulating WAT accumulation in this model. Using a doxycycline-inducible mouse model for Deptor overexpression, we confirmed that Deptor promotes WAT expansion in vivo. DEPTOR expression is elevated in WAT of obese humans and strongly correlates with the degree of obesity. We show that DEPTOR is induced during adipogenesis and that its overexpression cell-autonomously promotes, while its suppression blocks, adipogenesis. DEPTOR positively regulates adipogenesis by promoting the activity of the pro-adipogenic factors Akt/PKB and PPAR-gamma. These results establish DEPTOR as a physiological regulator of adipogenesis and provide new insights into the molecular mechanisms controlling WAT formation.
Project description:DDB1 is typically recognized as a component of the Cullin4 (CUL4)-RING E3 ubiquitin ligase complex. Here, we show that DDB1 functions independently of CUL4 to promote adipogenesis and diet-induced obesity. In contrast to depletion of CUL4A or CUL4B that stimulates adipogenesis, lack of DDB1 dramatically suppresses the process. Re-introduction of a DDB1 mutant that lacks the binding ability to CUL4A or CUL4B fully restores adipogenesis in DDB1-deficient preadipocytes. Furthermore, while inducibly knocking out Cul4a or Cul4b in mice aggravates diet-induced obesity, Ddb1+/- mice are lean on high-fat diet. Mechanistically, by binding the bromodomain-containing histone reader BRWD3, DDB1 is recruited to acetylated histones in the proximal promoters of immediate-early response genes, where it facilitates the release of paused RNA polymerase II (Pol II) and activates the transcription of these genes. Our findings have thus uncovered a mechanism of activating the transcriptional cascade in adipogenesis by DDB1-mediated release of paused Pol II.
Project description:DDB1 is typically recognized as a component of the Cullin4 (CUL4)-RING E3 ubiquitin ligase complex. Here, we show that DDB1 functions independently of CUL4 to promote adipogenesis and diet-induced obesity. In contrast to depletion of CUL4A or CUL4B that stimulates adipogenesis, lack of DDB1 dramatically suppresses the process. Re-introduction of a DDB1 mutant that lacks the binding ability to CUL4A or CUL4B fully restores adipogenesis in DDB1-deficient preadipocytes. Furthermore, while inducibly knocking out Cul4a or Cul4b in mice aggravates diet-induced obesity, Ddb1+/- mice are lean on high-fat diet. Mechanistically, by binding the bromodomain-containing histone reader BRWD3, DDB1 is recruited to acetylated histones in the proximal promoters of immediate-early response genes, where it facilitates the release of paused RNA polymerase II (Pol II) and activates the transcription of these genes. Our findings have thus uncovered a mechanism of activating the transcriptional cascade in adipogenesis by DDB1-mediated release of paused Pol II.