Delivery of Adipose-Derived Stem Cells Attenuates Adipose Tissue Inflammation and Insulin Resistance in Obese Mice Through Remodeling Macrophage Phenotypes

Adipose-derived stem cells (ADSCs) have been used to control several autoimmune or inflammatory diseases due to immunosuppressive properties, but their role in obesity-associated inflammation remains unestablished. This study aims to evaluate the effects of ADSCs on obesity-induced white adipose tissue (WAT) inflammation and insulin resistance. We found that diet-induced obesity caused a remarkable reduction of ADSC fraction in mouse WAT. Delivery of lean mouse-derived ADSCs, which could successfully locate into WAT of obese mice, substantially improved insulin action and metabolic homeostasis of obese mice. ADSC treatment not only reduced adipocyte hypertrophy but also attenuated WAT inflammation by reducing crown-like structures of macrophages and tumor necrosis factor (TNF)-α secretion. Importantly, ADSC treatment remodeled the phenotypes of adipose-resident macrophages from proinflammatory M1 toward anti-inflammatory M2-like subtypes, as characterized by decreased MHC class II-expressing but increased interleukin (IL)-10-producing macrophages together with low expression of TNF-α and IL-12. Coculture of ADSCs through the transwell or conditional medium with induced M1 macrophages also reproduced the phenotypic switch toward M2-like macrophages, which was substantiated by elevated arginase 1, declined inducible nitric oxide synthase, inhibition of NF-κB activity, and activation of STAT3/STAT6. Taken together, our data support that ADSC supplement in obese mice could sustain IL-10-producing M2-like macrophages in WAT through paracrine action, thereby suggesting the crucial role of ADSCs in resolving WAT inflammation, maintaining adipose homeostasis, and proposing a potential ADSC-based approach for the treatment of obesity-related diseases.