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A Drosophila model targets Eiger/TNFα to alleviate obesity-related insulin resistance and macrophage infiltration.

ABSTRACT: Obesity is associated with various metabolic disorders, such as insulin resistance and adipose tissue inflammation (ATM), characterized by macrophage infiltration into adipose cells. This study presents a new Drosophila model to investigate the mechanisms underlying these obesity-related pathologies. We employed genetic manipulation to reduce ecdysone levels to prolong the larval stage. These animals are hyperphagic and exhibit features resembling obesity in mammals, including increased lipid storage, adipocyte hypertrophy and high circulating glucose levels. Moreover, we observed significant infiltration of immune cells (hemocytes) into the fat bodies, accompanied by insulin resistance. We found that attenuation of Eiger/TNFα signaling reduced ATM and improved insulin sensitivity. Furthermore, using metformin and the antioxidants anthocyanins, we ameliorated both phenotypes. Our data highlight evolutionarily conserved mechanisms allowing the development of Drosophila models for discovering therapeutic pathways in adipose tissue immune cell infiltration and insulin resistance. Our model can also provide a platform to perform genetic screens or test the efficacy of therapeutic interventions for diseases such as obesity, type 2 diabetes and non-alcoholic fatty liver disease.

SUBMITTER: Mirzoyan Z

PROVIDER: S-EPMC10651092 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature

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A Drosophila model targets Eiger/TNFα to alleviate obesity-related insulin resistance and macrophage infiltration.

Mirzoyan Zhasmine Z Valenza Alice A Zola Sheri S Bonfanti Carola C Arnaboldi Lorenzo L Ferrari Nicholas N Pollard John J Lupi Valeria V Cassinelli Matteo M Frattaroli Matteo M Sahin Mehtap M Pasini Maria Enrica ME Bellosta Paola P

Disease models & mechanisms 20231106 11

Obesity is associated with various metabolic disorders, such as insulin resistance and adipose tissue inflammation (ATM), characterized by macrophage infiltration into adipose cells. This study presents a new Drosophila model to investigate the mechanisms underlying these obesity-related pathologies. We employed genetic manipulation to reduce ecdysone levels to prolong the larval stage. These animals are hyperphagic and exhibit features resembling obesity in mammals, including increased lipid st ...[more]

PMID: 37828911

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Project description:Background/objectivesLimited numbers of studies demonstrated obesity-induced macrophage infiltration in skeletal muscle (SM), but dynamics of immune cell accumulation and contribution of T cells to SM insulin resistance are understudied.Subjects/methodsT cells and macrophage markers were examined in SM of obese humans by reverse transcription-PCR (RT-PCR). Mice were fed high-fat diet (HFD) for 2-24 weeks, and time course of macrophage and T-cell accumulation was assessed by flow cytometry and quantitative RT-PCR. Extramyocellular adipose tissue (EMAT) was quantified by high-resolution micro-computed tomography (CT), and correlation to T-cell number in SM was examined. CD11a-/- mice and C57BL/6 mice were treated with CD11a-neutralizing antibody to determine the role of CD11a in T-cell accumulation in SM. To investigate the involvement of Janus kinase/signal transducer and activator of transcription (JAK/STAT), the major pathway for T helper I (TH1) cytokine interferon-γ, in SM and adipose tissue inflammation and insulin resistance, mice were treated with a JAK1/JAK2 inhibitor, baricitinib.ResultsMacrophage and T-cell markers were upregulated in SM of obese compared with lean humans. SM of obese mice had higher expression of inflammatory cytokines, with macrophages increasing by 2 weeks on HFD and T cells increasing by 8 weeks. The immune cells were localized in EMAT. Micro-CT revealed that EMAT expansion in obese mice correlated with T-cell infiltration and insulin resistance. Deficiency or neutralization of CD11a reduced T-cell accumulation in SM of obese mice. T cells polarized into a proinflammatory TH1 phenotype, with increased STAT1 phosphorylation in SM of obese mice. In vivo inhibition of JAK/STAT pathway with baricitinib reduced T-cell numbers and activation markers in SM and adipose tissue and improved insulin resistance in obese mice.ConclusionsObesity-induced expansion of EMAT in SM was associated with accumulation and proinflammatory polarization of T cells, which may regulate SM metabolic functions through paracrine mechanisms. Obesity-associated SM 'adiposopathy' may thus have an important role in the development of insulin resistance and inflammation.

Dataset Information

A Drosophila model targets Eiger/TNFα to alleviate obesity-related insulin resistance and macrophage infiltration.

Publications

A Drosophila model targets Eiger/TNFα to alleviate obesity-related insulin resistance and macrophage infiltration.

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