LIFR-alpha/JAK/STAT3-dependent Adipose Inflammation Contributes to Obesity-Associated NAFLD - Resubmissi

摘要 虽然脂肪炎症与肥胖有关，但它在重编程脂肪细胞和其他细胞中的作用 肥胖症的代谢合并症包括脂肪变性的发展中的脂肪仍不清楚。的 脂肪组织内复杂的细胞内（基质、血管、免疫和脂肪细胞）相互作用最终 通过平衡脂肪细胞三酰甘油（TAG）脂解和合成来调节其大小。炎症信号 这些细胞类型之间的相互作用也可能影响脂肪细胞对cAMP调节剂的反应。了解 这些相互作用的收敛，我们以前确定细胞因子白血病抑制因子（LIF）作为一个 增加脂肪炎症和脂解的分泌分子。高脂肪饮食（HFD）的野生型小鼠 结果显示，与正常饮食的匹配动物相比，LIF和IL-6脂肪mRNA高7倍。当 将重组LIF给予野生型小鼠，其通过JAK/STAT 3 - 1引起>50%的脂肪量损失。 依赖性脂肪组织重编程，增加脂解和放大炎症通过改变 其他细胞/脂肪因子的表达。JAK抑制剂治疗rLIF施用小鼠抑制脂肪损失 通过1）抑制脂肪炎症，如通过降低的STAT 3磷酸化测定的，2）降低的 脂肪细胞脂解，和3）抑制细胞/脂肪因子变化。为了证明这个信号的重要性 我们选择性地沉默了LIF受体（LIFR-α，基因LIFR）或STAT 3。 脂肪细胞中，并评估饮食诱导的肥胖症中的鼠发育。两种模型都减少了脂肪 炎症导致脂肪量增加50%，肝脏总TAG水平降低约75% 与对照组相比，限制了这些小鼠中的非酒精性脂肪性肝病（NAFLD）和脂肪性肝炎。 相反，在HFD小鼠中，我们观察到JAK/STAT反调节因子SOCS 3的脂肪细胞沉默， 相反的表型，与对照组相比，脂肪量减少约30%。我们假设 LIFR-α/JAK/STAT 3依赖性细胞因子-脂肪-肝轴促进脂肪炎症，导致 增加脂解和改变其他细胞/脂肪因子的表达。这个轴的激活限制了脂肪 扩增，导致TAG从脂肪向肝脏的动员，并最终促成 NAFLD/脂肪性肝炎。这种炎症驱动的轴也影响脂肪对全身代谢的反应， 改变，使脂肪细胞对其他cAMP调节剂的脂解调节敏感。最后，我们提出了初步的 IL-6家族的细胞因子通过JAK/STAT 3诱导腺苷酸环化酶5的表达而发出信号 （ADCY 5）在调节脂质动员中重编程脂肪细胞。SA 1将评价脂肪细胞中LIFR-α/JAK/STAT 3信号级联对细胞因子-脂肪-肝轴的贡献。SA 2将使用基于遗传学的方法来验证马槟榔碱介导的脂肪细胞重编程在促进脂质动员中的作用。 需要ADCY 5功能。SA 3将在我们的多个小鼠模型中使用单细胞RNA-Seq技术来鉴定 炎症调节的肥胖和NAFLD的非脂肪细胞贡献者。

ABSTRACT Although adipose inflammation is associated with obesity, its role in reprogramming adipocytes and other cells in adipose towards the development of obesity’s metabolic comorbidities including steatosis remain unclear. The complex intracellular (stromal, vascular, immune, and adipocyte) interactions within adipose tissue ultimately regulate its size by balancing adipocyte triacylglyceride (TAG) lipolysis and synthesis. The inflammatory signaling of and between these cell types may also influence adipocyte responses to cAMP modulators. To understand the convergence of these interactions, we previously identified cytokine leukemia inhibitory factor (LIF) as a secretory molecule that increased adipose inflammation and lipolysis. Wild type mice on a high fat diet (HFD) demonstrated 7-fold higher LIF and IL-6 adipose mRNA than matched animals on normal diets. When recombinant LIF was administered to wild-type mice, it caused >50% loss of fat mass through JAK/STAT3- dependent reprogramming of adipose tissue, increasing lipolysis and amplifying inflammation by altering the expression of other cyto/adipokines. JAK inhibitor treatment of rLIF-administered mice suppressed adipose loss through 1) inhibition of adipose inflammation as determined by decreased STAT3 phosphorylation, 2) decreased adipocyte lipolysis, and 3) inhibition of cyto/adipokine changes. To establish the importance of this signaling pathway to adipose inflammation, we selectively silenced LIF receptor (LIFR-α, gene LIFR) or STAT3 in adipocytes and assessed murine development in diet-induced obesity. Both models had decreased adipose inflammation resulting in a 50% increase in adipose mass and a ~75% reduction in total hepatic TAG levels compared to controls, limiting non-alcoholic fatty liver disease (NAFLD) and steatohepatitis in these mice. Conversely, with adipocyte silencing of the JAK/STAT counter-regulator SOCS3 in mice on HFDs, we observed the opposite phenotype with a ~30% reduction in adipose mass compared to controls. We hypothesize that a LIFR-α/JAK/STAT3-dependent Cytokine-Adipose-Hepatic Axis facilitates adipose inflammation, leading to increased lipolysis and altered expression of other cyto/adipokines. The activation of this axis limits adipose expansion, resulting in TAG mobilization from adipose to the liver and ultimately contributing to NAFLD/steatohepatitis. This inflammatory-driven axis also affects adipose responses to systemic metabolic change, sensitizing adipocytes to lipolytic regulation by other cAMP modulators. Finally, we present preliminary data that the IL-6 family of cytokines signal through JAK/STAT3 inducing the expression of adenylyl cyclase 5 (ADCY5) to reprogram adipocytes in regulating lipid mobilization. SA1 will evaluate the contribution of the LIFR-α/JAK/STAT3 signaling cascade in adipocytes to the Cytokine-Adipose-Hepatic Axis. SA2 will use a genetics-based approach to verify that cytokine-mediated reprogramming of adipocytes in promoting lipid mobilization requires ADCY5 function. SA3 will use single cell RNA-Seq techniques in our multiple mouse models to identify non-adipocyte contributors to inflammation-regulated obesity and NAFLD.