白血病抑制因子 (LIF) 是 IL-6 细胞因子家族的成员，在体内平衡和疾病中发挥着核心作用。有趣的是，LIF 的一些多效性效应归因于巨噬细胞功能的调节，尽管其分子基础尚未在全基因组范围内得到探索。在此，我们通过 RNA-seq 研究了小鼠骨髓源性巨噬细胞 (BMDM) 中 LIF 驱动的转录变化。计算机分析揭示了与脂质代谢和细胞激活相关的巨噬细胞基因表达程序的选择性和时间依赖性重塑。因此，通过 RT-qPCR 验证了与胆固醇代谢和脂质内化相关的 LIF 上调转录物的子集。与氧化低密度脂蛋白 (Ox-LDL) 一起孵育后，LIF 增强了巨噬细胞中脂质积累的能力。从机制上讲，LIF 触发 BMDM 中转录因子 STAT3 的磷酸化（Y705 和 S727）和核转位。与此一致的是，Ingenuity Pathway Analysis (IPA) 确定 STAT3 是 LIF 处理的巨噬细胞中转录子子集（包括 Il4ra）的上游调节因子。值得注意的是，LIF 引发增强了 BMDM 对 IL-4 介导的 M2 极化的反应（即增加了精氨酸酶活性和编码 M2 标记的转录物的积累）。相反，LIF 刺激对 BMDM 对 M1 极化刺激（IFNγ 和 LPS）的反应没有显着影响。因此，我们的研究深入了解了 LIF 处理的巨噬细胞的转录情况，揭示了其在脂质代谢和 M2 极化反应中的作用。更好地了解控制 LIF 驱动变化的调节机制可能有助于了解旨在重新编程疾病状态（例如癌症、动脉粥样硬化、感染等）中巨噬细胞表型的新治疗方法。© 作者 2024 年。牛津大学出版大学出版社代表白细胞生物学学会。

Leukemia inhibitory factor (LIF), a member of the IL-6 cytokine family, plays a central role in homeostasis and disease. Interestingly, some of the pleiotropic effects of LIF have been attributed to the modulation of macrophage functions although the molecular underpinnings have not been explored at a genome-wide scale. Herein, we investigated LIF-driven transcriptional changes in murine bone marrow-derived macrophages (BMDM) by RNA-seq. In silico analyses revealed a selective and time-dependent remodelling of macrophage gene expression programs associated with lipid metabolism and cell activation. Accordingly, a subset of LIF-upregulated transcripts related to cholesterol metabolism and lipid internalization was validated by RT-qPCR. This was accompanied by a LIF-enhanced capacity for lipid accumulation in macrophages upon incubation with oxidated low-density lipoprotein (Ox-LDL). Mechanistically, LIF triggered the phosphorylation (Y705 and S727) and nuclear translocation of the transcription factor STAT3 in BMDM. Consistent with this, Ingenuity Pathway Analysis (IPA) identified STAT3 as an upstream regulator of a subset of transcripts, including Il4ra, in LIF-treated macrophages. Notably, LIF priming enhanced BMDM responses to IL-4-mediated M2 polarization (i.e., increased arginase activity and accumulation of transcripts encoding for M2 markers). Conversely, LIF stimulation had no significant effect in BMDM responses to M1 polarizing stimuli (IFNγ and LPS). Thus, our study provides insight into the transcriptional landscape of LIF-treated macrophages, shedding light on its role in lipid metabolism and M2 polarization responses. A better understanding of the regulatory mechanisms governing LIF-driven changes might help informing novel therapeutic approaches aiming to reprogram macrophage phenotypes in diseased states (e.g., cancer, atherosclerosis, infection, etc.).© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology.