Dataset Information

The role of IRAKM in IL-1β-treated adipocytes

ABSTRACT: Toll-like receptors/Interleukin-1 receptor (IL-1R) signaling plays an important role in High-fat diet (HFD)-induced adipose tissue dysfunction contributing to obesity-associated metabolic syndromes. Here, we show an unconventional IL-1R-IRAKM (IL-1R-associated kinase M)-Slc25a1 signaling axis in adipocytes that reprograms lipogenesis to promote diet-induced obesity. Adipocyte-specific deficiency of IRAKM reduced HFD-induced body weight gain, increased whole body energy expenditure and improved insulin resistance, associated with decreased lipid accumulation and adipocyte cell sizes. IL-1β stimulation induced the translocation of IRAKM Myddosome to mitochondria to promote de novo lipogenesis in adipocytes. Mechanistically, IRAKM interacts with and phosphorylates mitochondrial citrate carrier Slc25a1 to promote IL-1β-induced mitochondrial citrate transport to cytosol and de novo lipogenesis. Moreover, IRAKM-Slc25a1 axis mediates IL-1β induced Pgc1a acetylation to regulate thermogenic gene expression in adipocytes. IRAKM kinase-inactivation also attenuated HFD-induced obesity. Taken together, our study suggests that the IL-1R-IRAKM-Slc25a1 signaling axis tightly links inflammation and adipocyte metabolism, indicating a novel therapeutic target for obesity.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Adipocyte

DISEASE(S): Obesity

SUBMITTER: Ling Li

LAB HEAD: Xiaoxia Li

PROVIDER: PXD031934 | Pride | 2022-06-09

REPOSITORIES: Pride

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Publications

IL-1R-IRAKM-Slc25a1 signaling axis reprograms lipogenesis in adipocytes to promote diet-induced obesity in mice.

Liu Weiwei W Zhou Hao H Wang Han H Zhang Quanri Q Zhang Renliang R Willard Belinda B Liu Caini C Kang Zizhen Z Li Xiao X Li Xiaoxia X

Nature communications 20220518 1

Toll-like receptors/Interleukin-1 receptor signaling plays an important role in high-fat diet-induced adipose tissue dysfunction contributing to obesity-associated metabolic syndromes. Here, we show an unconventional IL-1R-IRAKM-Slc25a1 signaling axis in adipocytes that reprograms lipogenesis to promote diet-induced obesity. Adipocyte-specific deficiency of IRAKM reduces high-fat diet-induced body weight gain, increases whole body energy expenditure and improves insulin resistance, associated w ...[more]

PMID: 35585086

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Project description:Obesity due to overnutrition causes adipose tissue dysfunction, serving as a critical pathological step on the road to Type 2 diabetes (T2D) and other metabolic disorders. Here, we performed an unbiased investigation into the fundamental molecular mechanisms by which adipocytes transition to an unhealthy state during obesity. We fed NuTRAP (Nuclear tagging and Translating Ribosome Affinity Purification) mice crossed with Adipoq-Cre with chow or high fat diet (HFD) for 10 weeks and determined adipocyte-specific transcriptomic profiles by RNA-seq, active promoter and enhancer activities by H3K27ac ChIP-seq, and the PPARg cistrome by ChIP-seq. We also assessed the impact of the PPARg agonist rosiglitazone (Rosi) on gene expression and cellular state of adipocytes from HFD-fed mice. We used bioinformatic approaches to find transcriptional pathways and performed functional studies using shRNA-mediated loss-of-function approaches in 3T3-L1 adipocytes. Adipocytes from HFD-fed mice exhibited reduced expression of adipocyte markers and metabolic genes while showing enhanced expression of myofibroblast marker genes involved in cytoskeletal organization, accompanied by the formation of actin filament structures within the cell. PPARg binding was globally reduced in adipocytes after HFD feeding, and Rosi restored the molecular and cellular phenotypes of adipocytes associated with HFD feeding. SMAD binding motifs were over-represented in HFD-induced promoters and enhancers, while TGFb1 expression was elevated in adipose tissues after HFD feeding. TGFb1 treatment of mature 3T3-L1 adipocytes induced gene expression and cellular changes similar to those seen after HFD in vivo, and knockdown of Smad3 blunted the effects of TGFb1. Our data demonstrate that adipocytes fail to maintain cellular identity after HFD, acquiring characteristics of a myofibroblast-like cell type through reduced PPARg activity and elevated TGFb-SMAD signaling. This cellular identity crisis may serve as a fundamental mechanism that drives functional decline of adipose tissues during obesity.

Project description:Abstract Background In obesity, adipose tissue undergoes a remodeling process characterized by increased adipocyte size (hypertrophia) and number (hyperplasia). The individual ability to tip the balance toward the hyperplastic growth, with recruitment of new fat cells through adipogenesis, seems to be critical for a healthy adipose tissue expansion, as opposed to the development of inflammation and detrimental metabolic consequences. However, the molecular mechanisms underlying this fine-tuned regulation are far from being understood. Methods We analyzed by mass spectrometry-based proteomics visceral white adipose tissue (vWAT) samples collected from C57BL6 mice fed with a HFD for 8 weeks. A subset of these mice, called low responders (LowR HFD), showed a low susceptibility to the onset of adipose tissue inflammation, as opposed to their HFD counterpart. We identified the discriminants between LowR HFD and HFD vWAT samples and explored their function in Adipose Derived human Mesenchymal Stem Cells (AD-hMSCs) differentiated to adipocytes. Results We quantified 6051 proteins. Among the candidates that most differentiate LowR HFD from HFD vWAT, we found proteins involved in adipocyte function, including adiponectin and hormone sensitive lipase, suggesting that adipocyte differentiation is enhanced in LowR HFD, as compared to HFD. The chromatin modifier SET and MYND Domain Containing 3 (SMYD3), whose function in adipose tissue was totally unknown, was another top-scored hit. SMYD3 expression was significantly higher in LowR HFD vWAT, as confirmed by western blot analysis. In vitro, we found that SMYD3 mRNA and protein levels decrease rapidly along the differentiation process of AD-hMSCs. Moreover, SMYD3 knock-down at the beginning of adipocyte differentiation resulted in reduced cell proliferation and, at longer term, reduced lipid accumulation in adipocytes. Conclusions Our study describes for the first time the role of SMYD3 as a regulator of adipocyte proliferation during the early steps of adipogenesis.

Dataset Information

The role of IRAKM in IL-1β-treated adipocytes

Publications

IL-1R-IRAKM-Slc25a1 signaling axis reprograms lipogenesis in adipocytes to promote diet-induced obesity in mice.

Similar Datasets

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