Endocrinology department, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain.
Department of Biochemistry and Physiology, School of Pharmacy and Food Sciences, Institute of Biomedicine of the University of Barcelona (IBUB), Universitat de Barcelona (UB), Barcelona, Spain.
Front Endocrinol (Lausanne). 2024 Mar 13;15:1346317. doi: 10.3389/fendo.2024.1346317. eCollection 2024.
Obesity is a chronic condition associated with low-grade inflammation mainly due to immune cell infiltration of white adipose tissue (WAT). WAT is distributed into two main depots: subcutaneous WAT (sWAT) and visceral WAT (vWAT), each with different biochemical features and metabolic roles. Proinflammatory cytokines including interleukin (IL)-16 are secreted by both adipocytes and infiltrated immune cells to upregulate inflammation. IL-16 has been widely studied in the peripheral proinflammatory immune response; however, little is known about its role in adipocytes in the context of obesity.
AIM & METHODS: We aimed to study the levels of IL-16 in WAT derived from sWAT and vWAT depots of humans with obesity and the role of this cytokine in palmitate-exposed 3T3-L1 adipocytes.
The results demonstrated that IL-16 expression was higher in vWAT compared with sWAT in individuals with obesity. In addition, IL-16 serum levels were higher in patients with obesity compared with normal-weight individuals, increased at 6 months after bariatric surgery, and at 12 months after surgery decreased to levels similar to before the intervention. Our in vitro models showed that IL-16 could modulate markers of adipogenesis (Pref1), lipid metabolism (Plin1, Cd36, and Glut4), fibrosis (Hif1a, Col4a, Col6a, and Vegf), and inflammatory signaling (IL6) during adipogenesis and in mature adipocytes. In addition, lipid accumulation and glycerol release assays suggested lipolysis alteration.
Our results suggest a potential role of IL-16 in adipogenesis, lipid and glucose homeostasis, fibrosis, and inflammation in an obesity context.
肥胖是一种与低度炎症相关的慢性疾病，主要是由于免疫细胞浸润白色脂肪组织（WAT）。WAT 分为两个主要储存库：皮下 WAT（sWAT）和内脏 WAT（vWAT），每个储存库都具有不同的生化特征和代谢作用。包括白细胞介素（IL）-16 在内的促炎细胞因子由脂肪细胞和浸润的免疫细胞分泌，以上调炎症反应。IL-16 在周围促炎免疫反应中得到了广泛研究，但关于其在肥胖情况下脂肪细胞中的作用知之甚少。
我们旨在研究肥胖人群的 sWAT 和 vWAT 来源的 WAT 中 IL-16 的水平，以及这种细胞因子在棕榈酸暴露的 3T3-L1 脂肪细胞中的作用。
结果表明，肥胖个体的 vWAT 中 IL-16 的表达高于 sWAT。此外，肥胖患者的血清 IL-16 水平高于体重正常者，在减肥手术后 6 个月升高，并在手术后 12 个月下降至干预前水平。我们的体外模型表明，IL-16 可以在脂肪生成过程中和成熟脂肪细胞中调节脂肪生成标志物（Pref1）、脂质代谢（Plin1、Cd36 和 Glut4）、纤维化（Hif1a、Col4a、Col6a 和 Vegf）和炎症信号（IL6）。此外，脂质积累和甘油释放试验表明脂肪分解发生改变。
我们的结果表明，IL-16 在肥胖背景下可能在脂肪生成、脂质和葡萄糖稳态、纤维化和炎症中发挥作用。
