Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908, USA.
Department of Surgery, University of Virginia, Charlottesville, VA 22908, USA.
Sci Signal. 2023 Oct 24;16(808):eadg1553. doi: 10.1126/scisignal.adg1553.
Lung ischemia-reperfusion injury (IRI), characterized by inflammation, vascular permeability, and lung edema, is the major cause of primary graft dysfunction after lung transplantation. Here, we investigated the cellular mechanisms underlying lung IR-induced activation of endothelial TRPV4 channels, which play a central role in lung edema and dysfunction after IR. In a left lung hilar-ligation model of IRI in mice, we found that lung IRI increased the efflux of ATP through pannexin 1 (Panx1) channels at the endothelial cell (EC) membrane. Elevated extracellular ATP activated Ca influx through endothelial TRPV4 channels downstream of purinergic P2Y2 receptor (P2Y2R) signaling. P2Y2R-dependent activation of TRPV4 channels was also observed in human and mouse pulmonary microvascular endothelium in ex vivo and in vitro models of IR. Endothelium-specific deletion of P2Y2R, TRPV4, or Panx1 in mice substantially prevented lung IRI-induced activation of endothelial TRPV4 channels and lung edema, inflammation, and dysfunction. These results identify endothelial P2Y2R as a mediator of the pathological sequelae of IRI in the lung and show that disruption of the endothelial Panx1-P2Y2R-TRPV4 signaling pathway could be a promising therapeutic strategy for preventing lung IRI after transplantation.
肺缺血再灌注损伤（IRI）的特征是炎症、血管通透性和肺水肿，是肺移植后原发性移植物功能障碍的主要原因。在这里，我们研究了肺 IRI 激活内皮 TRPV4 通道的细胞机制，该通道在 IR 后肺水肿和功能障碍中起核心作用。在小鼠肺门结扎的 IRI 左肺模型中，我们发现肺 IRI 通过内皮细胞（EC）膜上的 Panx1（Panx1）通道增加了 ATP 的外排。细胞外 ATP 升高通过嘌呤能 P2Y2 受体（P2Y2R）信号下游的内皮 TRPV4 通道激活 Ca 内流。在 IR 的体外和体内模型中，还观察到人类和小鼠肺微血管内皮中 P2Y2R 依赖性的 TRPV4 通道激活。在小鼠中内皮细胞特异性敲除 P2Y2R、TRPV4 或 Panx1 可显著预防肺 IRI 诱导的内皮 TRPV4 通道激活和肺水肿、炎症和功能障碍。这些结果表明内皮 P2Y2R 是肺 IRI 病理后果的介导物，并表明破坏内皮 Panx1-P2Y2R-TRPV4 信号通路可能是预防移植后肺 IRI 的一种有前途的治疗策略。
