Key Laboratory for Experimental Teratology of Ministry of Education, Department of Immunology, Shandong University School of Basic Medical Sciences, Jinan, Shandong 250012, People's Republic of China.
Department of Clinical Laboratory, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong 250012, People's Republic of China.
J Immunol. 2020 Apr 15;204(8):2232-2241. doi: 10.4049/jimmunol.1901246. Epub 2020 Mar 16.
Sepsis is a life-threatening condition with limited therapeutic options, characterized as excessive systemic inflammation and multiple organ failure. Macrophages play critical roles in sepsis pathogenesis. Metabolism orchestrates homeostasis of macrophages. However, the precise mechanism of macrophage metabolism during sepsis remains poorly elucidated. In this study, we identified the key role of zinc fingers and homeoboxes (Zhx2), a ubiquitous transcription factor, in macrophage glycolysis and sepsis by enhancing 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (Pfkfb3) expression. Mice with myeloid Zhx2-specific deletion (abbreviated as MKO) showed more resistance to cecal ligation and puncture and LPS-induced sepsis, exhibiting as prolonged survival, attenuated pulmonary injury, and reduced level of proinflammatory cytokines, such as TNF-α, IL-6, and IL-1β. Interestingly, Zhx2 deletion conferred macrophage tolerance to LPS-induced glycolysis, accompanied by reduced proinflammatory cytokines and lactate. Consistently, treatment of glycolytic inhibitor 2-deoxyglucose almost completely abrogated the protection of mice from LPS-induced sepsis initiated by Zhx2 deletion in macrophages. RNA sequencing and chromatin immunoprecipitation assays confirmed that Zhx2 enhanced transcription of Pfkfb3, the glycolysis rate-limiting enzyme, via binding with promoter. Furthermore, Pfkfb3 overexpression not only rescued the reduction of macrophage glycolysis caused by Zhx2 deficiency, displaying as extracellular acidification rates and lactate production but also destroyed the resistance of mice to LPS-induced sepsis initiated by transfer of bone marrow-derived macrophages from MKO mice. These findings highlight the novel role of transcription factor Zhx2 in sepsis via regulating Pfkfb3 expression and reprogramming macrophage metabolism, which would shed new insights into the potential strategy to intervene sepsis.
脓毒症是一种危及生命的疾病，治疗选择有限，其特征为过度的全身炎症和多器官衰竭。巨噬细胞在脓毒症发病机制中起着关键作用。代谢调节巨噬细胞的内稳态。然而，巨噬细胞代谢在脓毒症中的精确机制仍未被充分阐明。在这项研究中，我们通过增强 6-磷酸果糖-2-激酶/果糖-2,6-二磷酸酶 3（Pfkfb3）的表达，确定了普遍存在的转录因子锌指和同源盒（Zhx2）在巨噬细胞糖酵解和脓毒症中的关键作用。骨髓特异性 Zhx2 缺失（缩写为 MKO）的小鼠对盲肠结扎和穿刺以及 LPS 诱导的脓毒症表现出更高的抵抗力，表现为存活时间延长、肺损伤减轻以及促炎细胞因子（如 TNF-α、IL-6 和 IL-1β）水平降低。有趣的是，Zhx2 缺失赋予巨噬细胞对 LPS 诱导的糖酵解的耐受性，同时减少促炎细胞因子和乳酸。一致地，糖酵解抑制剂 2-脱氧葡萄糖的治疗几乎完全消除了 Zhx2 缺失对 LPS 诱导的巨噬细胞脓毒症的保护作用。RNA 测序和染色质免疫沉淀测定证实，Zhx2 通过与启动子结合增强了糖酵解限速酶 Pfkfb3 的转录。此外，Pfkfb3 的过表达不仅挽救了 Zhx2 缺失引起的巨噬细胞糖酵解减少，表现为细胞外酸化率和乳酸生成减少，而且破坏了从 MKO 小鼠骨髓来源的巨噬细胞转移引起的 LPS 诱导的脓毒症的小鼠抵抗。这些发现强调了转录因子 Zhx2 通过调节 Pfkfb3 的表达和重塑巨噬细胞代谢在脓毒症中的新作用，这为干预脓毒症提供了新的思路。
