State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China; National Clinical Research Center for Infectious Diseases, 79 Qingchun Rd., Hangzhou City 310003, China.
State Key Laboratory for the Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, 79 Qingchun Rd., Hangzhou City 310003, China; National Clinical Research Center for Infectious Diseases, 79 Qingchun Rd., Hangzhou City 310003, China; Key Laboratory of Diagnosis and Treatment of Aging and Physic-chemical Injury Diseases of Zhejiang Province, 79 Qingchun Rd, Hangzhou City 310003, China.
Pharmacol Res. 2022 May;179:106229. doi: 10.1016/j.phrs.2022.106229. Epub 2022 Apr 22.
Acute liver injury (ALI) is characterized by massive hepatocyte necrosis and subsequent recruitment of myeloid cells to liver. Mesenchymal stem cells (MSCs) have therapeutic potential for ALI through their immunoregulation on macrophages, but the mechanism is not completely clear due to the heterogeneity and controversy of liver macrophages. Here, we detected the survival rate, biochemical indexes, histopathology, and inflammatory chemokine levels to assess the efficacy of MSC treatment on CCl-induced ALI of C57BL/6 mice. Furthermore, flow cytometry and single-cell RNA sequencing (scRNA-Seq) were used to precisely distinguish macrophage populations and reveal the immunoregulation of MSCs. MSC treatment could effectively alleviate ALI and mitigate the recruitment of mononuclear phagocytes. Flow cytometry and scRNA-Seq analyses collectively indicated that there were monocytes with high Ly6C expression and heterogeneous monocyte-derived macrophages (MoMF) with low Ly6C expression in liver. Ly6C pro-inflammatory monocytes and Ly6C MoMF with powerful phagocytosis dominated during the acute injury period. MSC treatment promoted the transition from Ly6C to Ly6C population, inhibit the proinflammatory function of monocytes and promote the lysosomal function of MoMF. Furthermore, MSCs attenuated the recruitment of neutrophils by reducing the expression of CXCL2 of MoMF. MoMF with high expression of arginase 1 appeared during the recovery period, and MSCs could increase their expression of arginase 1, which may promote liver repair. To sum up, we demonstrated the characteristics of distinct MoMF during different periods of ALI and revealed their functional changes after MSC treatment, providing immunotherapeutic targets for MSC treatment of ALI.
急性肝损伤（ALI）的特征是大量肝细胞坏死，随后髓系细胞招募到肝脏。间充质干细胞（MSCs）通过对巨噬细胞的免疫调节，对 ALI 具有治疗潜力，但由于肝巨噬细胞的异质性和争议，其机制尚不完全清楚。在这里，我们检测了存活率、生化指标、组织病理学和炎症趋化因子水平，以评估 MSC 治疗对 C57BL/6 小鼠 CCl 诱导的 ALI 的疗效。此外，流式细胞术和单细胞 RNA 测序（scRNA-Seq）用于精确区分巨噬细胞群，并揭示 MSCs 的免疫调节作用。MSC 治疗可有效缓解 ALI 并减轻单核细胞的募集。流式细胞术和 scRNA-Seq 分析共同表明，肝脏中有高 Ly6C 表达的单核细胞和低 Ly6C 表达的异质性单核细胞衍生的巨噬细胞（MoMF）。Ly6C 促炎单核细胞和具有强大吞噬作用的 Ly6C MoMF 在急性损伤期占主导地位。MSC 治疗促进了从 Ly6C 向 Ly6C 群体的转变，抑制单核细胞的促炎功能，并促进 MoMF 的溶酶体功能。此外，MSC 通过减少 MoMF 的 CXCL2 表达来减少中性粒细胞的募集。在恢复期出现高表达精氨酸酶 1 的 MoMF，MSC 可增加其精氨酸酶 1 的表达，这可能促进肝脏修复。总之，我们展示了 ALI 不同时期不同 MoMF 的特征，并揭示了 MSC 治疗后它们功能的变化，为 MSC 治疗 ALI 提供了免疫治疗靶点。
