Wuxi School of Medicine, Jiangnan University, Wuxi, China.
Department of Vascular & Cardiology, Ruijin Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
Free Radic Biol Med. 2024 Jul;219:141-152. doi: 10.1016/j.freeradbiomed.2024.04.224. Epub 2024 Apr 16.
Pulmonary hypertension (PH) is a devastating disease that lacks effective treatment options and is characterized by severe pulmonary vascular remodeling. Pulmonary arterial endothelial cell (PAEC) dysfunction drives the initiation and pathogenesis of pulmonary arterial hypertension. Canonical transient receptor potential (TRPC) channels, a family of Ca-permeable channels, play an important role in various diseases. However, the effect and mechanism of TRPCs on PH development have not been fully elucidated. Among the TRPC family members, TRPC4 expression was markedly upregulated in PAECs from hypoxia combined with SU5416 (HySu)-induced PH mice and monocrotaline (MCT)-treated PH rats, as well as in hypoxia-exposed PAECs, suggesting that TRPC4 in PAECs may participate in the occurrence and development of PH. In this study, we aimed to investigate whether TRPC4 in PAECs has an aggravating effect on PH and elucidate the molecular mechanisms. We observed that hypoxia treatment promoted PAEC apoptosis through a caspase-12/endoplasmic reticulum stress (ERS)-dependent pathway. Knockdown of TRPC4 attenuated hypoxia-induced apoptosis and caspase-3/caspase-12 activity in PAECs. Accordingly, adeno-associated virus (AAV) serotype 6-mediated pulmonary endothelial TRPC4 silencing (AAV6-Tie-shRNA-TRPC4) or TRPC4 antagonist suppressed PH progression as evidenced by reduced right ventricular systolic pressure (RVSP), pulmonary vascular remodeling, PAEC apoptosis and reactive oxygen species (ROS) production. Mechanistically, unbiased RNA sequencing (RNA-seq) suggested that TRPC4 deficiency suppressed the expression of the proapoptotic protein sushi domain containing 2 (Susd2) in hypoxia-exposed mouse PAECs. Moreover, TRPC4 activated hypoxia-induced PAEC apoptosis by promoting Susd2 expression. Therefore, inhibiting TRPC4 ameliorated PAEC apoptosis and hypoxic PH in animals by repressing Susd2 signaling, which may serve as a therapeutic target for the management of PH.
肺动脉高压（PH）是一种破坏性疾病，缺乏有效治疗方法，其特征为严重的肺血管重构。肺动脉内皮细胞（PAEC）功能障碍驱动肺动脉高压的起始和发病机制。经典瞬时受体电位（TRPC）通道是一类 Ca 通透性通道，在各种疾病中发挥重要作用。然而，TRPC 对 PH 发展的影响和机制尚未完全阐明。在 TRPC 家族成员中，缺氧联合 SU5416（HySu）诱导的 PH 小鼠和野百合碱（MCT）处理的 PH 大鼠的 PAEC 以及缺氧暴露的 PAEC 中，TRPC4 的表达明显上调，表明 PAEC 中的 TRPC4 可能参与 PH 的发生和发展。在本研究中，我们旨在研究 PAEC 中的 TRPC4 是否对 PH 具有加重作用，并阐明其分子机制。我们观察到缺氧处理通过半胱天冬酶-12/内质网应激（ERS）依赖性途径促进 PAEC 凋亡。TRPC4 敲低可减轻缺氧诱导的 PAEC 凋亡和半胱天冬酶-3/半胱天冬酶-12 活性。因此，腺相关病毒（AAV）血清型 6 介导的肺动脉内皮 TRPC4 沉默（AAV6-Tie-shRNA-TRPC4）或 TRPC4 拮抗剂抑制 PH 进展，表现为右心室收缩压（RVSP）降低、肺血管重构、PAEC 凋亡和活性氧（ROS）产生减少。机制上，无偏 RNA 测序（RNA-seq）表明，TRPC4 缺乏可抑制缺氧暴露的小鼠 PAEC 中促凋亡蛋白 sushi 结构域包含蛋白 2（Susd2）的表达。此外，TRPC4 通过促进 Susd2 表达激活缺氧诱导的 PAEC 凋亡。因此，抑制 TRPC4 通过抑制 Susd2 信号转导改善动物的 PAEC 凋亡和缺氧性 PH，这可能成为 PH 管理的治疗靶点。
