摘要一：中国特发性肺动脉高压患者PTGIS基因突变情况及临床特征：多中心、回顾性研究

【背景】

肺动脉高压（Pulmonary arterial Hypertension，PAH）被称为“心血管系统癌症”，是因肺血管重构导致肺血管阻力升高，引发心力衰竭而致残致死的疑难危重心血管疾病。特发性肺动脉高压（Idiopathic Pulmonary Arterial Hypertension, IPAH）病因未明，诊断延迟，致残致死率高。PAH现有靶向药物仅能缓解症状，无法逆转肺血管重构和右心病变，靶向药物开发进入瓶颈期。PAH的病理生理学机制复杂，遗传、表观遗传和环境等因素存在交互作用。开发基于不同PAH亚型的分子机制探究，向个体化精准治疗策略转化迫在眉睫。在中国人群中，有大量IPAH疾病相关基因未被揭示。破译中国本土疾病密码是领域研究的难点和关键。目前肺动脉高压分类和风险评估局限于患者临床症状和活动耐量等指标分类，而面对患者本身的深入动态挖掘明显不足。肺动脉高压已逐渐进入临床患者为根基，疾病精准分子分型时代。近年来中国学者首次发现前列环素合酶基因（Prostaglandin I2 Synthase, PTGIS) 是中国IPAH新的疾病风险基因。携带PTGIS罕见突变PAH患者的全面临床特征未知。

【目的】  

本研究旨在更新中国IPAH患者携带PTGIS罕见有害变异频率，描绘携带PTGIS有害变异肺动脉高压患者特征，为后续早期诊断、致病机制研究和个体化精准治疗策略选择提供依据。

【方法】

本研究基于多中心、回顾性队列研究，更新中国IPAH患者携带PTGIS罕见有害变异的频率，系统性观察、分析PTGIS基因突变患者的临床特征和疾病表型。研究参与单位包括中国3个医学中心。研究对象为经右心导管检查确诊的IPAH患者。采集患者外周血样本，通过二代测序技术筛查PTGIS基因突变情况，更新中国IPAH患者中PTGIS罕见有害变异频率。整合患者人口统计学资料、临床基线数据、影像学资料及治疗信息，深入分析携带突变患者的临床特征。挖掘中国携带PTGIS基因突变的PAH患者家系。

【结果】

研究基于2008年至2022年中国多中心IPAH测序数据，在731例病因不明的PAH患者中，更新PTGIS罕见有害变异频率为5.2%。PTGIS p.A447T是热点突变，占比34.2 %。在已有初步功能学研究基础的4种突变20位患者中，发现携带PTGIS突变的患者具有独特临床表型。在PTGIS突变患者中，急性血管反应试验阳性患者占比高达20%，诊断年龄显著小于急性血管反应试验阴性患者。患者中75%为女性，确诊时心功能及活动耐量明显受损。15% PTGIS突变患者存在肺血管形态异常。发现中国携带PTGIS基因突变的PAH家系。

【结论】

在我国病因不明PAH患者中，PTGIS罕见有害变异频率为5.2%。其热点突变（p.A447T）呈现高频分布。携带PTGIS罕见有害变异的患者表现出独特的临床表型谱，包括高急性肺血管扩张试验阳性率伴早发诊断特征，以及部分患者合并肺血管形态学异常。本研究发现中国携带PTGIS基因突变PAH家系。

摘要二：PTGIS基因突变对肺动脉高压发生发展的作用

【背景】

肺动脉高压（Pulmonary Arterial Hypertension，PAH）病理生理学机制具有高度复杂性，其具体病不明，涉及遗传易感性、表观遗传调控与环境暴露因素间的动态交互作用。深入解析其病理机制并挖掘逆转疾病进程的关键治疗靶点，已成为核心科学命题。从发病机制层面，内皮细胞功能障碍被认为是重构进程的始动环节。然而，患者来源的肺组织多来源于肺移植，例数少，表型晚期，无法贴合肺动脉高压发生发展的特点。获取携带特定遗传变异的原代PAH患者肺血管内皮细胞面临重大技术挑战。基于患者体细胞重编程技术构建的人诱导多能干细胞（induced pluripotent stem cells，iPSCs）及其定向分化内皮细胞（iPSC-derived endothelial cells，iPSC-ECs）模型，可有效整合个体遗传背景与疾病表型特征。在动物模型方面，目前肺高血压动物模型多采用野百合碱、Sugen联合低氧等外界干预手段，在血流动力学特征和病理生理学表型方面与人类疾病存在显著差异。这种"种属鸿沟"严重制约基础研究成果向临床应用的转化效率。

【目的】

构建患者特异性iPSC-ECs模型开展分子机制研究，建立基于患者热点突变PTGIS p.A447T突变位点的啮齿类动物模型，旨在构建具有临床转化价值的精准研究工具，初步阐明该致病突变在PAH发生发展中的生物学效应。

【方法】

第一步使用PTGIS p.A447T突变的PAH患者和健康对照诱导多能干细胞定向分化为内皮细胞。同时引入患者修复PTGIS p.A447T突变、健康对照引入突变的人诱导多能干细胞进行实验。第二步探究AAV过表达患者PTGIS p.A447T对应位点突变对野百合碱肺高血压模型大鼠的作用。基于此结果趋势，构建PTGIS点突变基因编辑小鼠模型，探究PTGIS p.A447T体内实验研究结果。

【结果】

PTGIS p.A447T突变降低iPSC-ECs中PTGIS表达，降低PGI₂稳定代谢产物6-keto-PGF1α水平，影响内皮细胞功能, 修复突变可逆转趋势。AAV6过表达Ptgis c.1342 G>A加重野百合碱大鼠肺动脉高压模型。构建基于患者PTGIS p.A447T突变的小鼠模型，点突变小鼠PTGIS蛋白表达降低，肺动脉高压造模表型更重。

【结论】

PTGIS p.A447T突变降低iPSC-ECs细胞PTGIS表达和功能，PTGIS p.A447T突变破坏内皮细胞功能，修复突变可逆转。构建基于患者PTGIS p.A447T突变的啮齿类动物模型，点突变加重肺动脉高压造模表型。

Abstract 1. Distribution of PTGIS Mutations and Distinct Clinical Phenotypes in Idiopathic Pulmonary Arterial Hypertension: A Retrospective Multicenter Analysis

Background

Pulmonary arterial hypertension (PAH) is a detrimental cardiovascular disorder characterized by progressive pulmonary vascular remodeling, elevated pulmonary vascular resistance, and eventual right heart failure. Idiopathic pulmonary arterial hypertension (IPAH), with unknown etiology and frequent diagnostic delays, exhibits high rates of disability and mortality. Current targeted therapies only alleviate symptoms and fail to reverse pulmonary vascular remodeling or right heart dysfunction, highlighting a urgent need in precision drug development. The complex pathophysiology of PAH involves interactions among genetic, epigenetic, and environmental factors. Elucidating molecular mechanisms specific to PAH subtypes and advancing personalized treatment strategies are urgent priorities. In Chinese populations, a large proportion of IPAH-associated genetic variants remains unidentified, underscoring the necessity to uncover localized disease mechanisms. Current PAH classification and risk stratification rely only on clinical symptoms and exercise capacity metrics, lacking in-depth dynamic profiling of individual patients. PAH management is transitioning toward a precision medicine era, emphasizing molecular subtyping. Recent study by Chinese researchers identified the prostaglandin I2 synthase (PTGIS) gene as a novel risk locus for IPAH in this population. However,  clinical characterization of PAH patients harboring rare PTGIS mutations remains to be delineated.

Objectives

This study aims to characterize pulmonary arterial hypertension (PAH) patients carrying pathogenic PTGIS mutations and summarize the clinical features of those with rare PTGIS variants. The findings will provide a foundation for improving early diagnosis, clarifying disease mechanisms, and guiding personalized precision treatment strategies.

Results

Analysis of multicenter Chinese idiopathic pulmonary arterial hypertension (IPAH) sequencing data (2008 to 2022) revealed a 5.2% prevalence of rare pathogenic PTGIS variants in patients with unexplained PAH, with PTGIS p.A447T identified as the predominant hotspot mutation (34.2% of cases). Carriers of PTGIS mutations exhibited distinct clinical phenotypes: a female predominance (75%), and severe impairments in cardiac function and exercise capacity at diagnosis. Notably, 20% of PTGIS mutation carriers showed positive responses to acute vasoreactivity testing, with these patients diagnosed at a significantly younger age than non-responders. Abnormal pulmonary vascular morphology was observed in 15% of cases. Additionally, PTGIS mutation-positive PAH pedigrees demonstrated no co-occurrence of other established PAH-associated genetic variants, highlighting the unique role of PTGIS in these patients.

Conclusion

In Chinese patients with idiopathic pulmonary arterial hypertension (IPAH), rare pathogenic PTGIS variants were identified in 5.2% of cases, with the p.A447T mutation accounting for 34.2% of these variants. PTGIS mutation carriers exhibited distinct clinical features including a high proportion of positive acute vasoreactivity testing, younger age at diagnosis compared to non-responders, and abnormal pulmonary vascular morphology. Notably, PTGIS-specific PAH pedigrees were identified, underscoring its genetic relevance. These findings highlight unique phenotypic characteristics associated with PTGIS mutations, emphasizing their potential role in refining diagnostic strategies and personalized management for IPAH.

Abstract 2. Role of PTGIS Mutations in the Pathogenesis and Progression of Pulmonary Arterial Hypertension

Background

The pathophysiology of pulmonary arterial hypertension (PAH) is highly complex, with incomplete understanding of its etiology involving dynamic interactions among genetic predisposition, epigenetic regulation, and environmental factors. Elucidating its mechanisms and identifying therapeutic targets to reverse disease progression remain critical challenges. Endothelial dysfunction is recognized as a key driver of vascular remodeling; however, patient-derived lung tissues, often obtained from late-stage transplants, are scarce and fail to reflect early disease dynamics. Isolating primary endothelial cells from PAH patients with specific genetic variants poses significant technical barriers. Induced pluripotent stem cell (iPSC) models, generated by reprogramming patient-derived somatic cells and differentiated into endothelial cells (iPSC-ECs), offer a promising platform to integrate genetic backgrounds with disease phenotypes. Current PAH animal models exhibit marked species-related discrepancies in hemodynamic and pathophysiological features compared to human disease, severely limiting the translation of preclinical findings to clinical applications.

Objectives

This study developed patient-specific induced pluripotent stem cell-derived endothelial cell models and generated gene-edited mice harboring the PTGIS p.A447T mutation to establish translational research tools for investigating molecular mechanisms in pulmonary arterial hypertension. By integrating iPSC-EC models with genetic editing approaches, we aimed to elucidate the biological effects of this pathogenic variant on PAH initiation and progression. These models address limitations of conventional animal systems and provide a platform to bridge genetic insights with functional validation, advancing precision medicine strategies for PAH.

Results

We generated induced pluripotent stem cell-derived endothelial cells from three pulmonary arterial hypertension (PAH) patients carrying the PTGIS p.A447T mutation and three healthy controls. Isogenic lines were established by correcting the mutation in patient-derived iPSCs and introducing the PTGIS p.A447T variant into control iPSCs. The PTGIS p.A447T mutation significantly reduced PTGIS expression and 6-keto-PGF1α synthesis in iPSC-ECs, while genetic correction rescued these deficits. In vivo, AAV6-mediated overexpression of Ptgis c.1342 G>A (p.A447T) exacerbated pulmonary hypertension in monocrotaline-induced rat models. Furthermore, homozygous PTGIS p.A447T knock-in mice exhibited reduced PTGIS protein levels and more severe pulmonary hypertension phenotypes following hypoxia/SU5416 exposure compared to wild-type littermates.

Conclusion

The PTGIS p.A447T mutation was found to significantly reduce PTGIS expression and functional activity, as demonstrated by impaired prostacyclin synthesis in induced pluripotent stem cell-derived endothelial cells (iPSC-ECs). This mutation increased apoptosis susceptibility and disrupted tube formation capacity in iPSC-ECs, both of which were reversed upon genetic correction of the mutation. PTGIS  knock-in mouse exhibited decreased PTGIS protein levels and aggravated pulmonary hypertension (PH) phenotypes.