Nephrology Division, Department of Medicine, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Division of Cardiovascular Medicine, Department of Medicine, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
J Extracell Vesicles. 2023 Jul;12(7):e12334. doi: 10.1002/jev2.12334.
Progressive peritoneal fibrosis and the loss of peritoneal function often emerged in patients undergoing long-term peritoneal dialysis (PD), resulting in PD therapy failure. Varieties of cell-cell communications among peritoneal cells play a significant role in peritoneal fibrogenesis. Extracellular vesicles (EVs) have been confirmed to involve in intercellular communication by transmitting proteins, nucleic acids or lipids. However, their roles and functional mechanisms in peritoneal fibrosis remain to be determined. Using integrative analysis of EV proteomics and single-cell RNA sequencing, we characterized the EVs isolated from PD patient's effluent and revealed that mesothelial cells are the main source of EVs in PD effluent. We demonstrated that transforming growth factor-β1 (TGF-β1) can substitute for PD fluid to stimulate mesothelial cells releasing EVs, which in turn promoted fibroblast activation and peritoneal fibrogenesis. Blockade of EVs secretion by GW4869 or Rab27a knockdown markedly suppressed PD-induced fibroblast activation and peritoneal fibrosis. Mechanistically, injured mesothelial cells produced EVs containing high level of integrin-linked kinase (ILK), which was delivered to fibroblast and activated them via p38 MAPK signalling pathway. Clinically, the expression of ILK was up-regulated in fibrotic peritoneum of patients undergoing long-term PD. The percentage of ILK positive EVs in PD effluent correlated with peritoneal dysfunction and the degree of peritoneal damage. Our study highlights that peritoneal EVs mediate communications between mesothelial cells and fibroblasts to initiate peritoneal fibrogenesis. Targeting EVs or ILK could provide a novel therapeutic strategy to combat peritoneal fibrosis.
进行长期腹膜透析（PD）的患者常出现腹膜纤维化和腹膜功能丧失，导致 PD 治疗失败。腹膜细胞间的各种细胞-细胞通讯在腹膜纤维化中起重要作用。细胞外囊泡（EVs）已被证实通过传递蛋白质、核酸或脂质参与细胞间通讯。然而，它们在腹膜纤维化中的作用和功能机制仍有待确定。通过 EV 蛋白质组学和单细胞 RNA 测序的综合分析，我们对从 PD 患者流出液中分离出的 EVs 进行了表征，并揭示间皮细胞是 PD 流出液中 EVs 的主要来源。我们证明转化生长因子-β1（TGF-β1）可以替代 PD 液刺激间皮细胞释放 EVs，进而促进成纤维细胞激活和腹膜纤维化。GW4869 或 Rab27a 敲低阻断 EVs 分泌可显著抑制 PD 诱导的成纤维细胞激活和腹膜纤维化。机制上，受损的间皮细胞产生含有高水平整合素连接激酶（ILK）的 EVs，ILK 通过 p38 MAPK 信号通路被传递到成纤维细胞并激活它们。临床上，长期 PD 患者纤维化腹膜中 ILK 的表达上调。PD 流出液中 ILK 阳性 EVs 的百分比与腹膜功能障碍和腹膜损伤程度相关。我们的研究强调了腹膜 EVs 介导间皮细胞和成纤维细胞之间的通讯，从而引发腹膜纤维化。靶向 EVs 或 ILK 可能为治疗腹膜纤维化提供一种新的治疗策略。
