PPARγ lipodystrophy mutants reveal intermolecular interactions required for enhancer activation
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE199426 | GEO | 2022/10/27
REPOSITORIES: GEO
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Project description:The peroxisome proliferator-activated receptor γ (PPARγ) is the master regulator of adipocyte differentiation, and mutations that interfere with PPARγ function cause lipodystrophy. Structural studies indicate that PPARγ domains engage in several intra- and inter-moleuclar interactions; however, how these interactions modulate the ability of PPARγ to activate target genes in a cellular context is currently poorly understood. Here we analysed the transcriptional potential of R212Q and E379K two previously uncharacterised lipodystrophy-associated PPARγ mutants that are located in distinct PPARγ domains but are both predicted to affect intermolecular interactions. Using a combination of biochemical and genome-wide approaches we show that these mutations impair binding to an overlapping subset of enhancers that are less accessible and specifically require PPARγ for chromatin remodeling. Based on these findings we propose a model in which recruitment of PPARγ to chromatin is determined by several intermolecular interfaces. Furthermore, our data exemplify that relatively subtle molecular defects in transcription factors are sufficient to significantly affect enhancer binding and thereby transcriptional output.
2022-09-08 | PXD036589 | Pride
Project description:Adipocytes are the primary sites for fatty acid storage, but the synthesis rate of fatty acids is very low. The physiological significance of this phenomenon remains unclear. Here, we show that surplus fatty acid synthesis in adipocytes induces necroptosis and lipodystrophy. Transcriptional activation of FASN elevates fatty acid synthesis, but decreases NADPH level and increases ROS production, which ultimately leads to adipocyte necroptosis. We identify MED20, a subunit of the Mediator complex, as a negative regulator of FASN transcription. Adipocyte-specific male Med20 knockout mice progressively develop lipodystrophy, which is reversed by scavenging ROS. Further, in a murine model of HIV-associated lipodystrophy and a human patient with acquired lipodystrophy, ROS neutralization significantly improves metabolic disorders, indicating a causal role of ROS in disease onset. Our study well explains the low fatty acid synthesis rate in adipocytes, and sheds light on the management of acquired lipodystrophy.
2023-12-11 | GSE249808 | GEO
Project description:Background and objective: Combination antiretroviral therapy (cART) is associated with lipodystrophy i.e. loss of subcutaneous adipose tissue in abdomen, limbs and face and its accumulation intra-abdominally. No fat is lost dorsocervically and it can even accumulates in this region (“buffalo hump”). It is unknown how preserved dorsocervical fat differs from abdominal subcutaneous fat in HIV-1-infected cART-treated patients with (cART+LD+) and without (cART+LD-) lipodystrophy. Results: Albeit dorsocervical adipose tissue in cART+LD+ seems spared from lipoatrophy, its mitochondrial DNA (mtDNA, copies/cell) content was significantly lower (by 62%) than that of the corresponding tissue in cART+LD-. Expression of CD68 mRNA, a marker of macrophages, and numerous inflammatory genes in microarray were significantly lower in dorsocervical vs. abdominal subcutaneous adipose tissue. Genes with the greatest difference in expression between the two depots were those involved in regulation of transcription and regionalization (homeobox genes), irrespective of lipodystrophy status. There was negligible mRNA expression of uncoupling protein 1, a gene characteristic of brown adipose tissue, in either depot. Conclusions: As mtDNA is depleted even in the non-atrophic dorsocervical adipose tissue, it is unlikely that the cause of lipoatrophy is loss of mtDNA. Dorsocervical adipose tissue is less inflamed than lipoatrophic adipose tissue. It does not resemble brown adipose tissue. The greatest difference in gene expression between dorsocervical and abdominal s.c. adipose tissue is in expression of homeobox genes. We used histology, microarray, polymerase chain reaction and magnetic resonance imaging to compare dorsocervical and abdominal subcutaneous adipose tissue in cART+LD+ (n=21) and cART+LD- (n=11). The study consists of 17 patients on antiretroviral treatment who have developed lipodystrophy and 11 patients that are on similar treatment but have not developped lipodystrophy. All patients are HIV+ and have 2 adipose tissue samples taken from them (dorsocervical+abdominal).
2011-09-14 | E-GEOD-28073 | biostudies-arrayexpress
Project description:Genome wide DNA methylation profiling of Congenital Lipodystrophy type 2 patients, mutation carriers , and healthy control samples .The Infinium MethylationEPIC Kit was used to measure genome-wide DNA methylation across > 868,000 CpG sites.
2023-08-08 | GSE214297 | GEO
Project description:PLAAT3 is a phospholipid modifying enzyme predominantly expressed in neural and white adipose tissue (WAT). We identified loss-of-function variants in human PLAAT3 as the cause of a severe lipodystrophy syndrome associated with neurological with features. To identify the underlying molecular pathways associated with PLAAT3 deficiency, we performed RNA sequencing and differential gene expression analysis on WAT specimens from Plaat3 knockout mice.
2023-05-30 | GSE233433 | GEO
Project description:Congenital generalized lipodystrophy (CGL) is an autosomal recessive disorder characterized by defective adipose tissue, extreme insulin resistance, and early onset of diabetes. There are four types of congenital generalized lipodystrophy based on the causative genetic alterations. The symptoms and the degrees of disease progression are varied among all affected individuals, which might be due to unknown genetic modifiers. To identify potential predictive biomarkers associated with the disease progressions, we recruited 7 patients (cgl2_p1,cgl2_p2,cgl2_p3,cgl2_p4,cgl2_p5,cgl2_p6,cgl2_p7),as well as gender/aged-matched controls (cgl2_c1,cgl2_c2,cgl2_c3,cgl2_c4,cgl2_c5,cgl2_c6,cgl2_c7).The total RNA samples were extracted from the participants' peripheral blood mononuclear cells, followed by RNA-Seq. To find the molecular signatures that might be associated with disease progression, patients were further categorized into sub-groups based on the results of biochemical analysis and their clinical symptoms (e.g. diabetes, metabolic syndrome and metal retardation). DEGs were identified for each sub-groups of patients, and pathway analysis was performed to explore the underlying dysregulated mechanisms.
2021-08-18 | GSE159337 | GEO
Project description:We identified a microRNA (miRNA) profile characterizing HIV lipodystrophy and explored the downstream mechanistic implications with respect to adipocyte biology and the associated clinical phenotype. Human preadipocytes transfected with mimic miR-20a-3p, anti–miR-324-5p, or anti–miR-186 induced consistent changes in latent transforming growth factor beta binding protein 2 (Ltbp2), Wisp2, and Nebl expression.
2021-09-22 | GSE183822 | GEO
Project description:Background and objective: Combination antiretroviral therapy (cART) is associated with lipodystrophy i.e. loss of subcutaneous adipose tissue in abdomen, limbs and face and its accumulation intra-abdominally. No fat is lost dorsocervically and it can even accumulates in this region (“buffalo hump”). It is unknown how preserved dorsocervical fat differs from abdominal subcutaneous fat in HIV-1-infected cART-treated patients with (cART+LD+) and without (cART+LD-) lipodystrophy. Results: Albeit dorsocervical adipose tissue in cART+LD+ seems spared from lipoatrophy, its mitochondrial DNA (mtDNA, copies/cell) content was significantly lower (by 62%) than that of the corresponding tissue in cART+LD-. Expression of CD68 mRNA, a marker of macrophages, and numerous inflammatory genes in microarray were significantly lower in dorsocervical vs. abdominal subcutaneous adipose tissue. Genes with the greatest difference in expression between the two depots were those involved in regulation of transcription and regionalization (homeobox genes), irrespective of lipodystrophy status. There was negligible mRNA expression of uncoupling protein 1, a gene characteristic of brown adipose tissue, in either depot. Conclusions: As mtDNA is depleted even in the non-atrophic dorsocervical adipose tissue, it is unlikely that the cause of lipoatrophy is loss of mtDNA. Dorsocervical adipose tissue is less inflamed than lipoatrophic adipose tissue. It does not resemble brown adipose tissue. The greatest difference in gene expression between dorsocervical and abdominal s.c. adipose tissue is in expression of homeobox genes.
2011-09-15 | GSE28073 | GEO
Project description:Molecular defects in some ultra-rare subtypes of familial lipodystrophies remain unidentified. We identified novel NOTCH3 heterozygous variants in familial partial lipodystrophy (FPL) pedigrees. All variants were clustered in the heterodimerization domain of the negative regulatory region of NOTCH3. Proteomics of skin fibroblasts revealed significantly higher RNA expression of NOTCH3 and activation of widespread senescence pathways in the FPL patients versus controls.
2024-10-28 | MSV000096235 | MassIVE
Project description:PPARG interactome datasets containing (1) Flag-PPARG AP-MS, identifying MRE11, RAD50 and NBS1 as novel interactors, (2) tandem-IP (in solution and silver fragments) of PPARG-Strep and Flag-NBS1, which identifies PPARG interaction with UBR5 (3) tandem-IP (same as 2) with BS3 cross-linking illustrates the binding interface between PPARG and NBS1.
These mass spec data and other biochemical data demonstrate PPARG novel roles in promoting DNA damage response and repair, by activating the ATM pathway.
2018-12-18 | MSV000083257 | MassIVE