DataSheet_1_Single cell transcriptomic analyses reveal diverse and dynamic changes of distinct populations of lung interstitial macrophages in hypoxia-induced pulmonary hypertension.pdf

IntroductionHypoxia is a common pathological driver contributing to various forms of pulmonary vascular diseases leading to pulmonary hypertension (PH). Pulmonary interstitial macrophages (IMs) play pivotal roles in immune and vascular dysfunction, leading to inflammation, abnormal remodeling, and fibrosis in PH. However, IMs’ response to hypoxia and their role in PH progression remain largely unknown. We utilized a murine model of hypoxia-induced PH to investigate the repertoire and functional profiles of IMs in response to acute and prolonged hypoxia, aiming to elucidate their contributions to PH development.MethodsWe conducted single-cell transcriptomic analyses to characterize the repertoire and functional profiles of murine pulmonary IMs following exposure to hypobaric hypoxia for varying durations (0, 1, 3, 7, and 21 days). Hallmark pathways from the mouse Molecular Signatures Database were utilized to characterize the molecular function of the IM subpopulation in response to hypoxia.ResultsOur analysis revealed an early acute inflammatory phase during acute hypoxia exposure (Days 1-3), which was resolved by Day 7, followed by a pro-remodeling phase during prolonged hypoxia (Days 7-21). These phases were marked by distinct subpopulations of IMs: MHCIIhiCCR2+EAR2+ cells characterized the acute inflammatory phase, while TLF+VCAM1hi cells dominated the pro-remodeling phase. The acute inflammatory phase exhibited enrichment in interferon-gamma, IL-2, and IL-6 pathways, while the pro-remodeling phase showed dysregulated chemokine production, hemoglobin clearance, and tissue repair profiles, along with activation of distinct complement pathways.DiscussionOur findings demonstrate the existence of distinct populations of pulmonary interstitial macrophages corresponding to acute and prolonged hypoxia exposure, pivotal in regulating the inflammatory and remodeling phases of PH pathogenesis. This understanding offers potential avenues for targeted interventions, tailored to specific populations and distinct phases of the disease. Moreover, further identification of triggers for pro-remodeling IMs holds promise in unveiling novel therapeutic strategies for pulmonary hypertension.

缺氧作为一种常见的病理学驱动因素，是导致多种类型肺血管疾病进而引发肺动脉高压（PH）的重要因素。肺泡间质巨噬细胞（IMs）在免疫和血管功能障碍中扮演着关键角色，导致PH过程中的炎症、异常重塑和纤维化。然而，IMs对缺氧的反应及其在PH进展中的作用仍鲜为人知。本研究采用缺氧诱导的PH小鼠模型，旨在探究急性及长期缺氧下IMs的组成和功能特征，以阐明其对PH发展的贡献。

研究方法：我们通过对小鼠肺泡间质巨噬细胞进行单细胞转录组分析，以表征其在不同缺氧暴露时间（0、1、3、7和21天）下的组成和功能特征。利用小鼠分子特征数据库中的标志性通路，对IMs亚群在缺氧刺激下的分子功能进行表征。

研究结果：我们的分析揭示了急性缺氧暴露（第1-3天）早期急性炎症阶段，至第7天得到缓解，随后进入长期缺氧下的促重塑阶段（第7-21天）。这些阶段以不同的IMs亚群为特征：MHCIIhiCCR2+EAR2+细胞代表了急性炎症阶段，而TLF+VCAM1hi细胞则主导了促重塑阶段。急性炎症阶段富含干扰素-γ、IL-2和IL-6通路，而促重塑阶段则表现出趋化因子产生失调、血红蛋白清除和组织修复特征，以及不同补体通路的激活。

讨论：我们的研究结果揭示了与急性及长期缺氧暴露相对应的肺泡间质巨噬细胞特定亚群的存在，这些亚群在PH发病机制的炎症和重塑阶段调节中起着关键作用。这一认识为针对特定人群和疾病不同阶段的针对性干预提供了潜在途径。此外，进一步识别促重塑IMs的触发因素有望揭示肺动脉高压的新兴治疗策略。