Gene expression profile at single cell level of human pulmonary arteries (PA) of 2 healthy and 3 pulmonary hypertension associated with pulmonary fibrosis (PFPH) affected lungs
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ABSTRACT: Dysfunction of pulmonary arterial endothelial cells (PAECs) is associated with the development and progression of vascular pathology. However, it remains unknown how pulmonary hypertension (PH) affects cellular composition and transcriptomic profile of pulmonary endothelium. Here, we have undertaken a single-cell, compartment specific approach to characterise alterations in PAECs associated with two different types of PH, i.e., pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with pulmonary fibrosis (PHPF). Our unbiased analysis showed that endothelium of medium / small caliber pulmonary arteries is composed of three subsets of endothelial cells (ECs). The analysis of healthy and PH endothelium revealed that the three populations are persistently represented in remodelled arteries. Additionally, an exploratory analysis of human aorta (AO) and coronary arteries (CA) endothelium revealed that, although similar gene expression patterns were noticeable, PAECs subpopulations proportions differs significantly from pulmonary arteries (PA) endothelium. To address whether EC heterogeneity is a prime feature of human endothelium, we also performed a similar analysis in a murine model of hypoxia, revealing that similar EC populations were evident in this animal model. Comparative analysis of EC subpopulations in healthy and PH EC identified a common genetic deregulation accompanying vascular remodelling. Even though murine EC displayed some similarities with human EC subpopulations, the intense re-programming associated with hypoxia associated vascular remodelling displayed significant differences compared to the human disease. Finally, in depth comparative analysis of PAH and PHPF EC highlighted the development of disease-specific transcriptomic alterations in the three populations. Therefore, characterisation of transcriptomic differences in the endothelial bed of PAH and PHPF patients can facilitate identification of novel, disease-specific therapeutic targets.
Project description:Rationale: Pulmonary arterial hypertension (PAH) is a devastating disease characterized by obliterative vascular remodeling and persistent increase of vascular resistance, leading to right heart failure and premature death. Understanding the cellular and molecular mechanisms will help develop novel therapeutic approaches for PAH patients. Objectives: To determine whether upregulation of fatty-acid binding protein 4 and 5 (FABP4/5) is critical in pathogenesis of PAH. Methods: FABP4/5 expression was examined in pulmonary arterial endothelial cells (PAECs) and lung tissues from patients with idiopathic PAH and pulmonary hypertension (PH) rat models. Plasma proteome analysis was performed in human PAH samples. Echocardiography, hemodynamics, histology, and immunostaining were performed to evaluate the lung and heart PH phenotypes in Egln1Tie2Cre (CKO) mice and Egln1Tie2Cre/Fabp4-5-/- (TKO) mice. Measurement and Main Results: Both FABP4 and FABP5 were highly induced in ECs of CKO mice and PAECs from IPAH patients, and in whole lungs of PH rats. Plasma levels of FABP4/5 were upregulated in IPAH patients and directly correlated with severity of hemodynamics and biochemical parameters. Genetic deletion of both Fabp4 and 5 in CKO mice caused a reduction of right ventricular systolic pressure (RVSP) and RV hypertrophy, attenuated pulmonary vascular remodeling and prevented the right heart failure. Fabp4/5 deletion also normalized EC glycolysis, reduced ROS and HIF-2a expression, and decreased aberrant EC proliferation in CKO lungs. Conclusions: PH causes aberrant expression of FABP4/5 in pulmonary ECs which leads to enhanced EC glycolysis and hyperproliferation, contributing to the accumulation of arterial ECs and vascular remodeling and exacerbating the disease.
Project description:There is marked sexual dimorphism displayed in the onset and progression of pulmonary hypertension (PH). Females more commonly develop pulmonary arterial hypertension (PAH), however, females with PAH and other types of PH have better survival than males. Pulmonary microvascular endothelial cells play a crucial role in the pulmonary vascular remodelling and increased pulmonary vascular resistance of PH. Given this background, we hypothesized that there are sex differences in the pulmonary microvascular endothelium basally and in response to hypoxia that are independent of the sex hormone environment.
Project description:We investigate the MED1/KLF4 co-regulation of the BMP/TGF-beta axes in endothelium by studying the epigenetic regulation of BMP receptor type II (BMPR2), ETS-related gene (ERG), and TGF-beta receptor 2 (TGFBR2) and their involvement in the PH. High throughput screening involving data from RNA-seq, MED1 ChIP-seq, H3K27ac ChIP-seq, KLF4 ATAC-seq, and high-throughput chromosome conformation capture (HiC) together with in silico computations were used to explore the epigenetic and transcriptional regulation of BMPR2, ERG, and TGFBR2 by MED1 and KLF4. In vitro experiments with cultured pulmonary arterial endothelial cells (PAECs) and bulk assays were used to validate results from these in silico analyses. Lung tissue from patients with idiopathic pulmonary arterial hypertension (IPAH), animals with experimental PH, and mice with endothelial ablation of MED1 (EC-MED1-/-) were used to study the PH-protective effect of MED1. Levels of MED1 were decreased in lung tissue or PAECs from IPAH patients and rodent PH models. Mechanistically, MED1 acted synergistically with KLF4 to transactivate BMPR2, ERG, and TGFBR2 via chromatin remodeling and enhancer-promoter interactions. EC-MED1-/- mice showed PH susceptibility. In contrast, MED1 overexpression mitigated the PH phenotype in rodents. A homeostatic regulation of BMPR2, ERG, and TGFBR2 in ECs by MED1 synergistic with KLF4 is essential for the normal function of the pulmonary endothelium. Dysregulation of MED1 and the resulting impairment of the BMP/TGF- signaling is implicated in the disease progression of PAH in humans and PH in rodent models.
Project description:Pulmonary arterial hypertension (PAH) is characterized by endothelial cell (EC) dysfunction. There are no data from living patients to inform whether differential gene expression of pulmonary artery ECs (PAECs) can discern disease subtypes, progression and pathogenesis. We aimed to further validate our previously described method to propagate ECs from right heart catheter (RHC) balloon tips and to perform additional PAEC phenotyping. We performed bulk RNA sequencing of PAECs from RHC balloons. Using unsupervised dimensionality reduction and clustering we compared transcriptional signatures from PAH to controls and other forms of pulmonary hypertension. Select PAEC samples underwent single cell and population growth characterization and anoikis quantification. Fifty-four specimens were analyzed from 49 subjects. The transcriptome appeared stable over limited passages. Six genes involved in sex steroid signaling, metabolism, and oncogenesis were significantly upregulated in PAH subjects as compared to controls. Genes regulating BMP and Wnt signaling, oxidative stress and cellular metabolism were differentially expressed in PAH subjects. Changes in gene expression tracked with clinical events in PAH subjects with serial samples over time. Functional assays demonstrated enhanced replication competency and anoikis resistance. Our findings recapitulate fundamental biological processes of PAH and provide new evidence of a cancer-like phenotype in ECs from the central vasculature of PAH patients. This “cell biopsy” approach may provide insight into EC heterogeneity within the lung and a therapeutic screening approach in PAH.
Project description:SRY-Box Transcription Factor 17 (SOX17) enhancers variants and mutations are found in patients with pulmonary arterial hypertension (PAH). In human PAH pulmonary endothelial cells, there is a significant downregulation of SOX17 expression. We hypothesized that SOX17 deficiency contributes to the pathogenesis of PAH and found that mice with endothelial specific disruption (ecKO Sox17) developed spontaneous pulmonary hypertension (PH) and exacerbated hypoxia-induced PH. Loss of SOX17 in lung ECs induced endothelial dysfunctions including upregulation of cell cycle programming and paracrine effect, proliferative and anti-apoptotic phenotypes, impaired cellular junction and BMP signaling. E2F Transcription Factor 1 (E2F1) signaling was showed to mediate the SOX17 deficiency-induced EC dysfunction. Pharmacological inhibition of E2F1 in ecKO Sox17 mice attenuated PH and cell cycle programming. Our study demonstrated that endothelial SOX17 deficiency induces PH through E2F1 and targeting E2F1 signaling represents a promising approach in PAH patients.
Project description:Pulmonary arterial hypertension (PAH) is a fatal disease characterized by a proliferative endothelial cell phenotype, inflammation and pulmonary vascular remodeling. BMPR2 loss-of-function has been linked to pathologic plexiform lesions with obliteration of distal pulmonary arteries distal pulmonary arteries BMPR2 silencing inprimary human pulmonary artery ECs (HPAECs) recapitulate important aspects of cellular dysfunction and deregulated signaling associated with PAH. Primary HPAECs were transfected with gene-specific siRNA pools targeting BMPR2 or control siRNA followed PMA or control stimulation.
Project description:Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that culminates in right heart failure. Vascular pathology in PH is characterized by pulmonary vasoconstriction and progressive vascular remodeling processes that affects all layers of the vascular wall (intima, media and adventitia). Our objective was to profile and analyze the differential gene expression signatures between the cells isolated from normal and idiopathic PAH patients. We generated vascular cell-specific transcriptome profiles from the adventitial fibroblasts (PAAF) isolated ex vivo from the dissected human pulmonary arteries of normal donor and PAH lungs using paired-end RNA-sequencing.
Project description:Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that culminates in right heart failure. Vascular pathology in PH is characterized by pulmonary vasoconstriction and progressive vascular remodeling processes that affects all layers of the vascular wall (intima, media and adventitia). Our objective was to profile and analyze the differential gene expression signatures between the cells isolated from normal and idiopathic PAH patients. We generated vascular cell-specific transcriptome profiles from the adventitial fibroblasts (PAAF) isolated ex vivo from the dissected human pulmonary arteries of normal donor and PAH lungs using paired-end RNA-sequencing.
Project description:Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that culminates in right heart failure. Vascular pathology in PH is characterized by pulmonary vasoconstriction and progressive vascular remodeling processes that affects all layers of the vascular wall (intima, media and adventitia). Our objective was to profile and analyze the differential gene expression signatures between the cells isolated from normal and idiopathic PAH patients. We generated vascular cell-specific transcriptome profiles from the adventitial fibroblasts (PAAF) isolated ex vivo from the dissected human pulmonary arteries of normal donor and PAH lungs using paired-end RNA-sequencing.
Project description:Pulmonary arterial hypertension (PAH) is a progressive pulmonary vascular disease that culminates in right heart failure. Vascular pathology in PH is characterized by pulmonary vasoconstriction and progressive vascular remodeling processes that affects all layers of the vascular wall (intima, media and adventitia). Our objective was to profile and analyze the differential gene expression signatures between the cells isolated from normal and idiopathic PAH patients. We generated vascular cell-specific transcriptome profiles from the adventitial fibroblasts (PAAF) isolated ex vivo from the dissected human pulmonary arteries of normal donor and PAH lungs using paired-end RNA-sequencing.