Xu Feng, Jansakun Chutima, Li Gang, Biswas Uddipta, Poschet Gernot, Staffer Simone, Tuma-Kellner Sabine, Nakchbandi Inaam, Merle Uta, Chamulitrat Walee
Internal Medicine IV, Heidelberg University Hospital, Im Neuenheimer Feld 410, Heidelberg 69120, Germany; Gastrointestinal Cancer Research Institute, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, PR China.
Internal Medicine IV, Heidelberg University Hospital, Im Neuenheimer Feld 410, Heidelberg 69120, Germany; School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat 80161, Thailand.
Biomed Pharmacother. 2025 Jun;187:118146. doi: 10.1016/j.biopha.2025.118146. Epub 2025 May 8.
Genetic PLA2G6 variants are associated with C-reactive protein in humans. Myeloid-specific PLA2G6-deficient (Pla2g6) mice show increased hepatic myeloperoxidase and recruitment of granulocytes in response to lipopolysaccharide (LPS). We hypothesized that Pla2g6 mice could be protected from acetaminophen (APAP) hepatotoxicity whereby neutrophils, eosinophils, and alternatively activated macrophages are reportedly protective. Herein, Pla2g6 mice treated with 300 mg/kg APAP for 24 h showed attenuated hepatic necrosis and plasma cytokines, and with elevated levels of Ly6C in peripheral blood mononuclear cells and plasma lipoxin A4. Remarkably, bone-marrow-derived macrophages (BMDMs) from untreated Pla2g6 mice exhibited elevated baseline expression of cPLA2α, NOX2, Rac1, Arg-1, phospho-MLKL, and iNOS protein, which was exacerbated by LPS in vitro. APAP administration preconditioned Pla2g6 BMDMs for further activation of enzymes involving in phagocytosis (Rac1 and phospho-MLKL) and eicosanoids (COX2 and A15LOXB). Pla2g6 BMDMs showed an increased release of pro-resolution lipid mediators lipoxin A4, PGE2, and 15d-PGJ2, which was further elevated by LPS in vitro or APAP in vivo. Phagocytic gene signatures (myeloperoxidase and NOX2) were also upregulated in livers of untreated and APAP-treated Pla2g6 mice. APAP protection in Pla2g6 mice was associated with increased proportion of neutrophils (Ly6G), eosinophils (eosinophilic cationic protein), and M2 macrophages (CD206) in/at the portal tract and central vein as determined by immunohistochemistry. Thus, myeloid-specific PLA2G6 deficiency preconditioned macrophages for eicosanoid and phagocytic pathways rendering protection against APAP hepatotoxicity. Our results may be applicable to patients with PLA2G6 mutations, and PLA2G6 inhibition specifically in myeloid cells may represent a new strategy to alleviate APAP poisoning.
遗传型磷脂酶A2G6（PLA2G6）变体与人类的C反应蛋白相关。髓系特异性PLA2G6缺陷型（Pla2g6）小鼠在对脂多糖（LPS）产生反应时，肝脏髓过氧化物酶增加，粒细胞募集增多。我们推测Pla2g6小鼠可能对乙酰氨基酚（APAP）肝毒性具有抗性，据报道中性粒细胞、嗜酸性粒细胞和替代性活化巨噬细胞具有保护作用。在此，用300mg/kg APAP处理24小时的Pla2g6小鼠表现出肝脏坏死减轻、血浆细胞因子减少，外周血单核细胞中Ly6C水平升高以及血浆脂氧素A4升高。值得注意的是，未处理的Pla2g6小鼠的骨髓来源巨噬细胞（BMDM）表现出cPLA2α、NOX2、Rac1、Arg-1、磷酸化混合谱系激酶结构域样蛋白（phospho-MLKL）和诱导型一氧化氮合酶（iNOS）蛋白的基线表达升高，在体外LPS作用下这种升高会加剧。APAP给药预处理Pla2g6 BMDM以进一步激活参与吞噬作用的酶（Rac1和磷酸化MLKL）和类花生酸（环氧化酶2（COX2）和A15脂氧合酶（A15LOXB））。Pla2g6 BMDM显示促消退脂质介质脂氧素A4、前列腺素E2（PGE2）和15-脱氧-Δ12,14-前列腺素J2（15d-PGJ2）的释放增加，在体外LPS或体内APAP作用下进一步升高。在未处理和APAP处理的Pla2g6小鼠肝脏中，吞噬相关基因特征（髓过氧化物酶和NOX2）也上调。通过免疫组织化学测定，Pla2g6小鼠中APAP的保护作用与门管区和中央静脉中中性粒细胞（Ly6G）、嗜酸性粒细胞（嗜酸性阳离子蛋白）和M2巨噬细胞（CD206）比例增加有关。因此髓系特异性PLA2G6缺陷使巨噬细胞对类花生酸和吞噬途径产生预处理，从而对APAP肝毒性具有保护作用。我们的结果可能适用于携带PLA2G6突变的患者，并且特异性抑制髓系细胞中的PLA2G6可能代表一种减轻APAP中毒的新策略。
