Data_Sheet_1_Macrophages promote Fibrinogenesis during kidney injury.docx

Macrophages (Mø) are widely considered fundamental in the development of kidney fibrosis since Mø accumulation commonly aggravates kidney fibrosis, while Mø depletion mitigates it. Although many studies have aimed to elucidate Mø-dependent mechanisms linked to kidney fibrosis and have suggested various mechanisms, the proposed roles have been mostly passive, indirect, and non-unique to Mø. Therefore, the molecular mechanism of how Mø directly promote kidney fibrosis is not fully understood. Recent evidence suggests that Mø produce coagulation factors under diverse pathologic conditions. Notably, coagulation factors mediate fibrinogenesis and contribute to fibrosis. Thus, we hypothesized that kidney Mø express coagulation factors that contribute to the provisional matrix formation during acute kidney injury (AKI). To test our hypothesis, we probed for Mø-derived coagulation factors after kidney injury and uncovered that both infiltrating and kidney-resident Mø produce non-redundant coagulation factors in AKI and chronic kidney disease (CKD). We also identified F13a1, which catalyzes the final step of the coagulation cascade, as the most strongly upregulated coagulation factor in murine and human kidney Mø during AKI and CKD. Our in vitro experiments revealed that the upregulation of coagulation factors in Mø occurs in a Ca2 + −dependent manner. Taken together, our study demonstrates that kidney Mø populations express key coagulation factors following local injury, suggesting a novel effector mechanism of Mø contributing to kidney fibrosis.

巨噬细胞（Macrophages，简称Mø）被广泛认为是肾纤维化发生发展中的核心参与者，因其聚集通常会加重肾纤维化进程，而巨噬细胞清除则可缓解该病理过程。尽管诸多研究旨在阐明与肾纤维化相关的巨噬细胞依赖型致病机制，并提出了多种假说，但目前已提出的功能大多为间接、非特异性的被动作用，并非巨噬细胞所独有。因此，巨噬细胞直接促进肾纤维化的分子机制尚未完全明确。近期研究证据表明，巨噬细胞可在多种病理状态下分泌凝血因子。值得注意的是，凝血因子可介导纤维蛋白生成并参与纤维化进程。基于此，我们提出假说：肾组织巨噬细胞可表达凝血因子，参与急性肾损伤（AKI）过程中的临时基质形成。为验证该假说，我们对肾损伤后巨噬细胞来源的凝血因子进行了检测，结果发现，在急性肾损伤与慢性肾病（CKD）模型中，浸润型巨噬细胞与肾脏驻留型巨噬细胞均可分泌功能非冗余的凝血因子。我们还鉴定出凝血级联反应终末步骤的催化因子F13a1，其在急性肾损伤与慢性肾病过程中的小鼠及人源肾脏巨噬细胞中，是上调幅度最为显著的凝血因子。体外实验证实，巨噬细胞中凝血因子的上调表达以钙离子依赖的方式发生。综上，本研究证实，肾脏巨噬细胞群体在局部损伤后可表达关键凝血因子，这揭示了巨噬细胞促进肾纤维化的全新效应机制。