Interleukin-37 treatment of mice with metabolic syndrome improves insulin sensitivity and reduces pro-inflammatory cytokine production in adipose tissue.
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ABSTRACT: Obesity and the metabolic syndrome are characterized by chronic, low-grade inflammation mainly originating from expanding adipose tissue and resulting in inhibition of insulin signaling and disruption of glycemic control. Transgenic mice expressing human interleukin 37 (IL-37), an anti-inflammatory cytokine of the IL-1 family, are protected against metabolic syndrome when fed a high-fat diet (HFD) containing 45% fat. Here, we examined whether treatment with recombinant IL-37 ameliorates established insulin resistance and obesity-induced inflammation. WT mice were fed a HFD for 22 weeks and then treated daily with IL-37 (1 ?g/mouse) during the last 2 weeks. Compared with vehicle only-treated mice, IL-37-treated mice exhibited reduced insulin in the plasma and had significant improvements in glucose tolerance and in insulin content of the islets. The IL-37 treatment also increased the levels of circulating IL-1 receptor antagonist. Cultured adipose tissues revealed that IL-37 treatment significantly decreases spontaneous secretions of IL-1?, tumor necrosis factor ? (TNF?), and CXC motif chemokine ligand 1 (CXCL-1). We also fed mice a 60% fat diet with concomitant daily IL-37 for 2 weeks and observed decreased secretion of IL-1?, TNF?, and IL-6 and reduced intracellular levels of IL-1? in the liver and adipose tissue, along with improved plasma glucose clearance. Compared with vehicle treatment, these IL-37-treated mice had no apparent weight gain. In human adipose tissue cultures, the presence of 50 pm IL-37 reduced spontaneous release of TNF? and 50% of lipopolysaccharide-induced TNF?. These findings indicate that IL-37's anti-inflammatory effects can ameliorate established metabolic disturbances during obesity.
SUBMITTER: Ballak DB
PROVIDER: S-EPMC6139546 | biostudies-literature | 2018 Sep
REPOSITORIES: biostudies-literature
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