Frataxin deficiency as a cause of endothelial senescence in multiple subtypes of pulmonary hypertension

背景：内皮细胞(EC)病理生物学导致了肺动脉高压(PH)，但对 这种疾病中EC表型的演变已经持续了几十年。EC衰老，一种稳定的细胞状态 周期停滞，在PH中已有报道，但其调控特征尚不清楚。由我们之前的工作所领导的 在PH缺乏铁-硫(Fe-S)簇的情况下，我们发现一种铁-S生物发生蛋白Frataxin(FXN)控制着 肺内皮细胞的衰老。这可能发生在Friedreich共济失调(FRDA)中，这是一种以基因为标志的疾病 FXN缺乏，心肌病，常为PH。在这里，我们提供了一种新的PH中EC生物学模型，其中FXN 在FXN足够低的肺内皮细胞亚群中，Lost会促进遗传毒性应激和衰老。衰老 然后，ECS促进炎症，并推动许多PH亚型，包括FRDA和左心疾病的PH。 假设：我们提出FXN缺乏，由遗传或获得性手段驱动，协调铁-S依赖 基因毒性应激，促进EC衰老和多种PH亚型。目标1.确定FXN是否缺乏 促进DNA损伤以加强EC的衰老。人肺动脉和微血管内皮细胞的研究 并通过基因组编辑FRDA来源的可诱导多能干细胞(IPSC)来源的ECs中的FXN突变 我们将研究FXN在基因组应激和EC衰老中的作用。通过对循环因素的研究， 组织学和单细胞RNA测序，我们将评估血浆和罕见的肺标本中的EC衰老 来自PAH患者和合并肺血管疾病的FRDA和HCM患者。我们预计会看到一剂- FXN活性的依赖编排在EC衰老和PH时收敛。目标2.确定EC FXN 虚弱依赖于衰老和髓系炎症来推动PH。在第1组小鼠模型中 通过使用EC FXN-/-(KO)技术和腺相关病毒传递，FRDA导致的PAH和第2组PH FXN及其结合伙伴ISCU与肺内皮细胞的体内结合，我们将评估EC基因组应激，衰老， 炎症和PH。EC特异性p16 KO小鼠和CX3CR1 KO小鼠将被用来定义EC FXN是否依赖于 在衰老和下游髓系炎症时控制PH。因此，我们的目标是证明一种新的因果关系 PH中的EC生物学模型-一个解开了困扰这一问题的EC异质性困惑的模型 几十年来一直在田野里。目的3.确定一种新的GSTP1抑制剂是否能增加FXN并逆转多重PH 子类型。我们发现GSTP1抑制剂增加了FXN和ISCU，并改善了PH。我们将定义这一点 药物对改善1-2组PH模型的疗效以及FXN和GSTP1是否对其功能至关重要(通过 FXN和GSTP1/2KO小鼠)。如果是这样的话，我们可以定义一种全新的铁-S特异性疗法来治疗PH和FRDA。 意义：通过独特的人类和啮齿动物发现平台，我们将调查EC Fe-S星团- 控制多种PH亚型的衰老轴。我们的工作可以解释EC生物学在PH中的进化 和改变分子范例，特别是对于FRDA和第2族PH。我们的工作还将开发新的治疗方法 使用抗衰老药物控制铁-S的生物发生，特别适用于未经批准的第二组PH。

Background: Endothelial cell (EC) pathobiology drives pulmonary hypertension (PH), but confusion over the evolution of EC phenotypes in this disease has persisted for decades. EC senescence, a state of stable cell cycle arrest, has been reported in PH, but the regulatory features are unknown. Led by our prior work showing deficiency of iron-sulfur (Fe-S) clusters in PH, we found that a Fe-S biogenesis protein, frataxin (FXN), controls senescence in pulmonary ECs. This may occur in Friedreich’s ataxia (FRDA), a disease marked by genetic FXN deficiency, cardiomyopathy, and often PH. Here, we offer a new model of EC biology in PH, where FXN loss promotes genotoxic stress and senescence in a pulmonary EC subset with low enough FXN. Senescent ECs then promote inflammation and drive many PH subtypes, including PH of FRDA and left heart disease. Hypothesis: We propose FXN deficiency, driven by genetic or acquired means, orchestrates Fe-S-dependent genotoxic stress, enforcing EC senescence and multiple PH subtypes. Aim 1. Determine if FXN deficiency drives DNA damage to enforce EC senescence. By study of human pulmonary artery and microvascular ECs and via genome editing of FXN mutations in inducible pluripotent stem cell (iPSC)-derived ECs from FRDA patients, we will study the role of FXN in genomic stress and EC senescence. Via study of circulating factors, histology, and single cell RNA sequencing, we will assess EC senescence in plasma and rare lung specimens from PAH patients and FRDA and HCM patients with pulmonary vascular disease. We expect to see a dose- dependent orchestration of FXN activities converging on EC senescence and PH. Aim 2. Determine if EC FXN deficiency depends upon senescence and myeloid inflammation to drive PH. In mice models of Groups 1 PAH and Group 2 PH due to FRDA, by using EC FXN-/- (KO) technology and adeno-associated virus delivery of FXN and its binding partner ISCU to pulmonary ECs in vivo, we will assess EC genomic stress, senescence, inflammation, and PH. EC-specific p16 KO mice and CX3CR1 KO mice will be used to define if EC FXN depends upon senescence and downstream myeloid inflammation to control PH. Thus, we aim to prove a new causative model of EC biology in PH – one that deconvolutes the confusion over EC heterogeneity that has plagued this field for decades. Aim 3. Determine if a novel GSTP1 inhibitor increases FXN and reverses multiple PH subtypes. We found that a GSTP1 inhibitor increases FXN and ISCU and improves PH. We will define this drug’s efficacy for ameliorating Groups 1-2 PH models and if FXN and GSTP1 are crucial for its function (via FXN and GSTP1/2 KO mice). If so, we could define an entirely new Fe-S-specific therapy for PH and FRDA. Significance: Via unique human and rodent discovery platforms, we will investigate an EC Fe-S cluster- senescence axis controlling multiple PH subtypes. Our work could explain the evolution of EC biology in PH and shift molecular paradigms, particularly for FRDA and Group 2 PH. Our work will also develop new therapies using senolytic drugs to control Fe-S biogenesis, notably applicable to Group 2 PH with no approved treatments.