Peripheral leptin signaling persists in innate immune cells during diet-induced obesity. Issue 6 (18th October 2020)

• Record Type: Journal Article
• Authors: Souza-Almeida, Glaucia; Palhinha, Lohanna; Liechocki, Sally; da Silva Pereira, Jéssica Aparecida; Reis, Patrícia Alves; Dib, Paula Ribeiro Braga; Hottz, Eugenio D; Gameiro, Jacy; Vallochi, Adriana Lima; de Almeida, Cecília Jacques; Castro-Faria-Neto, Hugo; Bozza, Patrícia T; Maya-Monteiro, Clarissa Menezes
• Is Part Of: Journal of leukocyte biology. Volume 109:Issue 6(2021)
• Page Start: 1131
• Page End: 1138
• Publication Date: 2020-10-18
• Subjects: adipose tissue -- high-fat diet -- leptin signaling -- leukocytes -- macrophages -- neutrophils; Leucocytes -- Periodicals; Reticulo-endothelial system -- Periodicals; 571.96
• DOI: 10.1002/JLB.3AB0820-092RR
• Languages: English
• ISSNs: 0741-5400

Abstract

Abstract: Leptin is a pleiotropic adipokine that regulates immunometabolism centrally and peripherally. Obese individuals present increased levels of leptin in the blood and develop hypothalamic resistance to this adipokine. Here we investigated whether leptin effects on the periphery are maintained despite the hypothalamic resistance. We previously reported that leptin injection induces in vivo neutrophil migration and peritoneal macrophage activation in lean mice through TNF-α- and CXCL1-dependent mechanisms. However, leptin effects on leukocyte biology during obesity remain unclear. In this study, we investigated the in vivo responsiveness of leukocytes to i.p. injected leptin in mice with diet-induced obesity (DIO). After 14–16 wk, high-sucrose, high-fat diet (HFD)-fed mice showed hyperglycemia, hyperleptinemia, and dyslipidemia compared to normal-sucrose, normal-fat diet (ND). Exogenous leptin did not reduce food intake in DIO mice in contrast to control mice, indicating that DIO mice were centrally resistant to leptin. Regardless of the diet, we found increased levels of TNF-α and CXCL1 in the animals injected with leptin, alongside a pronounced neutrophil migration to the peritoneal cavity and enhanced biogenesis of lipid droplets in peritoneal macrophages. Supporting our in vivo results, data from ex vivo leptin stimulation experiments confirmed hypothalamic resistance in DIO mice, whereas bone marrow cells responded to leptin stimulation through mTOR signaling despite obesity. Altogether, our results show that leukocytes responded equally to leptin in ND- or HFD-fed mice. These results support a role for leptin in the innate immune response also in obesity, contributing to the inflammatory status that leads to the development of metabolic disease. Graphical Abstract: Leptin signaling in leukocytes persists in the periphery during obesity.