Characterising the transcriptional profile of murine 3T3-L1 adipocytes with altered expression of IRF3.. Mus musculus

The chronic inflammatory state that accompanies obesity is a major contributor to insulin resistance and other metabolic dysfunction features. Despite recent advances in our understanding of the cellular and secreted factors that promote the inflammatory milieu of obesity, we have much less insight into the transcriptional pathways that drive these processes. While most attention has focused on the canonical inflammatory transcription factor NF-KB, other potentially important factors exist, including members of the interferon regultory factor (IRF) family. Here we show that IRF3 expression is upregulated in the adipocytes of obese mice and humans. TLR3/TLR4 activation induces insulin resistance in adipocytes, which can be prevented by IRF3 knockdown. Furthermore, Irf3KO mice display improved insulin sensitivity, associated with reduced intra-adipose and systemic inflammation in the high-fat fed state, enhanced browning of subcutaneous fat, and increased adipose expression of Glut4. Taken together, our data indicates that IRF3 is a major transcriptional regulator of adipose inflammation to maintain systemic glucose and energy homeostasis. Overall design: Transcriptional profiling of murine 3T3-L1 adipocytes with altered expression of IRF3. Overexpression or knockdown of IRF3 was achieved by lentivirus transduction for 6 days. 3T3-L1 adipocytes with IRF3 knockdown were further treated in the absence or presence of LPS for 6 days. Samples consist of triplicate replica with appropriate control.

伴随肥胖发生的慢性炎症状态是胰岛素抵抗及其他代谢功能紊乱表现的主要诱因。尽管当前学界对介导肥胖炎症微环境的细胞与分泌因子已有了更为深入的认知，但对驱动这些进程的转录调控通路仍知之甚少。尽管多数研究聚焦于经典炎症转录因子核因子κB（NF-κB），但仍存在其他潜在的关键调控因子，包括干扰素调节因子（IRF）家族成员。本研究证实，IRF3在肥胖小鼠与人类的脂肪细胞中表达上调。Toll样受体3/4（TLR3/TLR4）激活可诱导脂肪细胞产生胰岛素抵抗，而该效应可通过敲低IRF3得以阻断。此外，Irf3基因敲除（Irf3KO）小鼠在高脂喂养状态下展现出更优的胰岛素敏感性，同时伴随脂肪组织内及全身性炎症水平降低、皮下脂肪褐变增强，以及脂肪组织葡萄糖转运蛋白4（Glut4）表达上调。综合以上实验结果，本研究数据表明IRF3是脂肪组织炎症的核心转录调控因子，可维持系统性葡萄糖与能量稳态。实验设计概要：对IRF3表达水平改变的小鼠3T3-L1脂肪细胞开展转录谱分析（Transcriptional profiling）。通过慢病毒转染处理6天，即可实现IRF3的过表达或敲低。对经IRF3敲低处理的3T3-L1脂肪细胞，进一步在有无脂多糖（LPS）的条件下培养6天。所有样本均设置三次生物学重复，并配备相应对照组。