The State Key Laboratory of Pharmaceutical Biotechnology, Division of Immunology, Medical School, Nanjing University, No. 22 Hankou Rd., Gulou District, Nanjing, Jiangsu, 210093, People's Republic of China.
Department of Obstetrics and Gynecology, Affiliated Hospital of Medical School, Nanjing Drum Tower Hospital, Nanjing University, Nanjing, China.
Stem Cell Res Ther. 2024 May 1;15(1):127. doi: 10.1186/s13287-024-03742-z.
Endometria are one of the important components of the uterus, which is located in the peritoneal cavity. Endometrial injury usually leads to intrauterine adhesions (IUA), accompanied by inflammation and cell death. We previously reported that both the endometrial ferroptosis was increased and monocytes/macrophages were involved in endometrial injury of IUA. Large peritoneal macrophages (LPMs) are recently reported to migrate into the injured tissues and phagocytose dead cells to repair the tissues. We previously demonstrated that mesenchymal stromal cells (MSCs) had made excellent progress in the repair of endometrial injury. However, it is unclear whether MSCs regulate the LPM efferocytosis against ferroptotic monocytes/macrophages in the injured endometria.
Here, endometrial injury in IUA mouse model was conducted by uterine curettage and LPS injection surgery and the samples were collected at different times to detect the changes of LPMs and ferroptotic monocytes/macrophages. We conducted LPMs depletion assay in vivo and LPMs and Erastin-induced ferroptotic THP-1 cells coculture systems in vitro to detect the LPM efferocytosis against ferroptotic monocytes/macrophages. The IUA model was treated with MSCs, and their effects on LPMs and endometrial repair were analyzed. Flow cytometry, western blotting, quantitative real-time PCR, immunohistochemical analysis, ELISA, and RNA-sequencing were performed.
We found that LPMs migrated to the injured uteri in response to the damage in early phase (3 h), and sustained to a later stage (7 days). Astonishingly, we found that ferroptotic monocytes/macrophages were significantly increased in the injured uteri since 12 h after injury. Moreover, LPMs cocultured with Erastin-induced ferroptotic THP-1 cells in vitro, efferocytosis of LPMs against ferroptotic monocytes/macrophages was emerged. The mRNA expression profiles revealed that LPM efferocytosis against ferroptotic monocytes/macrophages was an induction of glycolysis program and depended on the PPARγ-HK2 pathway. Importantly, we validated that MSCs promoted the efferocytic capability and migration of LPMs to the injured uteri via secreting stanniocalcin-1 (STC-1).
The data collectively demonstrated first the roles of LPMs via removal of ferroptotic monocytes/macrophages and provided a novel mechanism of MSCs in repairing the endometrial injury.
子宫内膜是子宫的重要组成部分之一，位于腹膜腔中。子宫内膜损伤通常会导致宫腔粘连（IUA），并伴有炎症和细胞死亡。我们之前的研究表明，子宫内膜铁死亡增加，单核细胞/巨噬细胞参与了 IUA 的子宫内膜损伤。最近有研究报道，大量腹膜巨噬细胞（LPMs）迁移到受损组织中，吞噬死亡细胞以修复组织。我们之前的研究表明，间充质基质细胞（MSCs）在子宫内膜损伤修复方面取得了很好的进展。然而，目前尚不清楚 MSCs 是否调节受损子宫内膜中 LPM 对铁死亡单核细胞/巨噬细胞的吞噬作用。
在这里，通过子宫刮除术和 LPS 注射手术构建 IUA 小鼠模型，并在不同时间点收集样本，以检测 LPMs 和铁死亡单核细胞/巨噬细胞的变化。我们在体内进行了 LPMs 耗竭实验，在体外进行了 LPMs 和 Erastin 诱导的铁死亡 THP-1 细胞共培养系统实验，以检测 LPMs 对铁死亡单核细胞/巨噬细胞的吞噬作用。用 MSCs 处理 IUA 模型，分析其对 LPMs 和子宫内膜修复的影响。进行流式细胞术、Western blot、实时定量 PCR、免疫组织化学分析、ELISA 和 RNA 测序。
我们发现 LPMs 在损伤早期（3 小时）迁移到受损的子宫，并持续到后期（7 天）。令人惊讶的是，我们发现损伤后 12 小时，受损子宫中的铁死亡单核细胞/巨噬细胞明显增加。此外，体外与 Erastin 诱导的铁死亡 THP-1 细胞共培养的 LPMs 中，LPMs 对铁死亡单核细胞/巨噬细胞的吞噬作用出现。mRNA 表达谱显示，LPMs 对铁死亡单核细胞/巨噬细胞的吞噬作用是糖酵解程序的诱导，依赖于 PPARγ-HK2 途径。重要的是，我们验证了 MSCs 通过分泌 STC-1 促进 LPMs 向受损子宫的吞噬作用和迁移。
这些数据首次证明了 LPMs 通过清除铁死亡单核细胞/巨噬细胞的作用，并提供了 MSCs 修复子宫内膜损伤的新机制。
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