Background:Mutations in PIEZO1 (Piezo type mechanosensitive ion channel component 1) cause human lymphatic malformations. We have previously uncovered an ORAI1 (ORAI calcium release-activated calcium modulator 1)-mediated mechanotransduction pathway that triggers lymphatic sprouting through Notch downregulation in response to fluid flow. However, the identity of its upstream mechanosensor remains unknown. This study aimed to identify and characterize the molecular sensor that translates the flow-mediated external signal to the Orai1-regulated lymphatic expansion.Methods:Various mutant mouse models, cellular, biochemical, and molecular biology tools, and a mouse tail lymphedema model were employed to elucidate the role of Piezo1 in flow-induced lymphatic growth and regeneration.Results:Piezo1 was found to be abundantly expressed in lymphatic endothelial cells. Piezo1 knockdown in cultured lymphatic endothelial cells inhibited the laminar flow-induced calcium influx and abrogated the flow-mediated regulation of the Orai1 downstream genes, such as KLF2 (Krüppel-like factor 2), DTX1 (Deltex E3 ubiquitin ligase 1), DTX3L (Deltex E3 ubiquitin ligase 3L,) and NOTCH1 (Notch receptor 1), which are involved in lymphatic sprouting. Conversely, stimulation of Piezo1 activated the Orai1-regulated mechanotransduction in the absence of fluid flow. Piezo1-mediated mechanotransduction was significantly blocked by Orai1 inhibition, establishing the epistatic relationship between Piezo1 and Orai1. Lymphatic-specific conditional Piezo1 knockout largely phenocopied sprouting defects shown in Orai1- or Klf2- knockout lymphatics during embryo development. Postnatal deletion of Piezo1 induced lymphatic regression in adults. Ectopic Dtx3L expression rescued the lymphatic defects caused by Piezo1 knockout, affirming that the Piezo1 promotes lymphatic sprouting through Notch downregulation. Consistently, transgenic Piezo1 expression or pharmacological Piezo1 activation enhanced lymphatic sprouting. Finally, we assessed a potential therapeutic value of Piezo1 activation in lymphatic regeneration and found that a Piezo1 agonist, Yoda1, effectively suppressed postsurgical lymphedema development.Conclusions:Piezo1 is an upstream mechanosensor for the lymphatic mechanotransduction pathway and regulates lymphatic growth in response to external physical stimuli. Piezo1 activation presents a novel therapeutic opportunity for preventing postsurgical lymphedema. The Piezo1-regulated lymphangiogenesis mechanism offers a molecular basis for Piezo1-associated lymphatic malformation in humans.

中文翻译：

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Piezo1 调节的机械传导控制流动激活的淋巴管扩张

背景：PIEZO1（压电型机械敏感离子通道成分1）的突变会导致人类淋巴管畸形。我们之前发现了 ORAI1（ORAI 钙释放激活钙调节剂 1）介导的机械传导途径，该途径通过响应液体流动而下调 Notch 来触发淋巴萌芽。然而，其上游机械​​传感器的身份仍然未知。本研究旨在鉴定和表征将流介导的外部信号转化为 Orai1 调节的淋巴管扩张的分子传感器。方法：采用了各种突变小鼠模型、细胞、生化和分子生物学工具以及小鼠尾部淋巴水肿模型阐明 Piezo1 在流动诱导的淋巴管生长和再生中的作用。结果：研究发现 Piezo1 在淋巴管内皮细胞中大量表达。培养的淋巴内皮细胞中的 Piezo1 敲低抑制了层流诱导的钙内流，并消除了 Orai1 下游基因的流介导调节，例如 KLF2（Krüppel 样因子 2）、DTX1（Deltex E3 泛素连接酶 1）、DTX3L（ Deltex E3 泛素连接酶 3L) 和 NOTCH1（Notch 受体 1），参与淋巴萌芽。相反，在没有液体流动的情况下，刺激 Piezo1 会激活 Orai1 调节的机械转导。Piezo1 介导的机械转导被 Orai1 抑制显着阻断，建立了 Piezo1 和 Orai1 之间的上位关系。淋巴特异性条件性 Piezo1 敲除很大程度上模仿了胚胎发育过程中 Orai1 或 Klf2 敲除淋巴管中显示的发芽缺陷。出生后 Piezo1 缺失会诱导成人淋巴消退。异位 Dtx3L 表达挽救了 Piezo1 敲除引起的淋巴缺陷，证实了 Piezo1 通过 Notch 下调促进淋巴萌芽。一致地，转基因 Piezo1 表达或药理学 Piezo1 激活增强了淋巴萌芽。最后，我们评估了 Piezo1 激活在淋巴再生中的潜在治疗价值，发现 Piezo1 激动剂 Yoda1 可以有效抑制术后淋巴水肿的发展。结论：Piezo1 是淋巴机械传导途径的上游机械传感器，可调节淋巴管生长以响应外部物理刺激。Piezo1 激活为预防术后淋巴水肿提供了新的治疗机会。Piezo1 调节的淋巴管生成机制为人类 Piezo1 相关淋巴管畸形提供了分子基础。