Department of Molecular and Cellular Physiology, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71103, USA.
Center for Cardiovascular Diseases and Sciences and Center for Redox Biology and Cardiovascular Disease, Louisiana State University Health Sciences Center-Shreveport, Shreveport, LA 71103, USA.
Endocrinology. 2023 Sep 23;164(11). doi: 10.1210/endocr/bqad143.
Glucocorticoids acting via the glucocorticoid receptors (GR) are key regulators of metabolism and the stress response. However, uncontrolled or excessive GR signaling adversely affects adipose tissue, including endocrine, immune, and metabolic functions. Inflammation of the adipose tissue promotes systemic metabolic dysfunction; however, the molecular mechanisms underlying the role of adipocyte GR in regulating genes associated with adipose tissue inflammation are poorly understood. We performed in vivo studies using adipocyte-specific GR knockout mice in conjunction with in vitro studies to understand the contribution of adipocyte GR in regulating adipose tissue immune homeostasis. Our findings show that adipocyte-specific GR signaling regulates adipokines at both mRNA and plasma levels and immune regulatory (Coch, Pdcd1, Cemip, and Cxcr2) mRNA gene expression, which affects myeloid immune cell presence in white adipose tissue. We found that, in adipocytes, GR directly influences Cxcr2. This chemokine receptor promotes immune cell migration, indirectly affecting Pdcd1 and Cemip gene expression in nonadipocyte or stromal cells. Our findings suggest that GR adipocyte signaling suppresses inflammatory signals, maintaining immune homeostasis. We also found that GR signaling in adipose tissue in response to stress is sexually dimorphic. Understanding the molecular relationship between GR signaling and adipose tissue inflammation could help develop potential targets to improve local and systemic inflammation, insulin sensitivity, and metabolic health.
糖皮质激素通过糖皮质激素受体 (GR) 发挥作用,是代谢和应激反应的关键调节剂。然而,不受控制或过度的 GR 信号会对脂肪组织产生不利影响,包括内分泌、免疫和代谢功能。脂肪组织的炎症会促进全身代谢功能障碍;然而,脂肪细胞 GR 调节与脂肪组织炎症相关基因的作用的分子机制尚不清楚。我们使用脂肪细胞特异性 GR 敲除小鼠进行体内研究,并结合体外研究,以了解脂肪细胞 GR 在调节脂肪组织免疫稳态中的作用。我们的研究结果表明,脂肪细胞特异性 GR 信号调节脂肪细胞因子在 mRNA 和血浆水平以及免疫调节(Coch、Pdcd1、Cemip 和 Cxcr2)mRNA 基因表达中的作用,这会影响髓样免疫细胞在白色脂肪组织中的存在。我们发现,在脂肪细胞中,GR 直接影响 Cxcr2。这种趋化因子受体促进免疫细胞迁移,间接影响非脂肪细胞或基质细胞中 Pdcd1 和 Cemip 基因的表达。我们的研究结果表明,GR 脂肪细胞信号抑制炎症信号,维持免疫稳态。我们还发现,脂肪组织对压力的 GR 信号具有性别二态性。了解 GR 信号与脂肪组织炎症之间的分子关系可能有助于开发潜在的靶点,以改善局部和全身炎症、胰岛素敏感性和代谢健康。