The Role of JAK/STAT Molecular Pathway in Vascular Remodeling Associated with Pulmonary Hypertension

Pulmonary hypertension is defined as a group of diseases characterized by a progressive increase in pulmonary vascular resistance (PVR), which leads to right ventricular failure and premature death. There are multiple clinical manifestations that can be grouped into five different types. Pulmonary artery remodeling is a common feature in pulmonary hypertension (PH) characterized by endothelial dysfunction and smooth muscle pulmonary artery cell proliferation. The current treatments for PH are limited to vasodilatory agents that do not stop the progression of the disease. Therefore, there is a need for new agents that inhibit pulmonary artery remodeling targeting the main genetic, molecular, and cellular processes involved in PH. Chronic inflammation contributes to pulmonary artery remodeling and PH, among other vascular disorders, and many inflammatory mediators signal through the JAK/STAT pathway. Recent evidence indicates that the JAK/STAT pathway is overactivated in the pulmonary arteries of patients with PH of different types. In addition, different profibrotic cytokines such as IL-6, IL-13, and IL-11 and growth factors such as PDGF, VEGF, and TGFβ1 are activators of the JAK/STAT pathway and inducers of pulmonary remodeling, thus participating in the development of PH. The understanding of the participation and modulation of the JAK/STAT pathway in PH could be an attractive strategy for developing future treatments. There have been no studies to date focused on the JAK/STAT pathway and PH. In this review, we focus on the analysis of the expression and distribution of different JAK/STAT isoforms in the pulmonary arteries of patients with different types of PH. Furthermore, molecular canonical and noncanonical JAK/STAT pathway transactivation will be discussed in the context of vascular remodeling and PH. The consequences of JAK/STAT activation for endothelial cells and pulmonary artery smooth muscle cells’ proliferation, migration, senescence, and transformation into mesenchymal/myofibroblast cells will be described and discussed, together with different promising drugs targeting the JAK/STAT pathway in vitro and in vivo.

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A Notch3-Marked Subpopulation of Vascular Smooth Muscle Cells Is the Cell of Origin for Occlusive Pulmonary Vascular Lesions

Circulation ◽

10.1161/circulationaha.120.045750 ◽

2020 ◽

Vol 142 (16) ◽

pp. 1545-1561

Author(s):

Lea C. Steffes ◽

Alexis A. Froistad ◽

Adam Andruska ◽

Mario Boehm ◽

Madeleine McGlynn ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Smooth Muscle Cells ◽

Vascular Remodeling ◽

Pulmonary Arteries ◽

Muscle Cells ◽

Neointima Formation ◽

Cell Of Origin ◽

Medial Thickening

Background: Pulmonary arterial hypertension (PAH) is a fatal disease characterized by profound vascular remodeling in which pulmonary arteries narrow because of medial thickening and occlusion by neointimal lesions, resulting in elevated pulmonary vascular resistance and right heart failure. Therapies targeting the neointima would represent a significant advance in PAH treatment; however, our understanding of the cellular events driving neointima formation, and the molecular pathways that control them, remains limited. Methods: We comprehensively map the stepwise remodeling of pulmonary arteries in a robust, chronic inflammatory mouse model of pulmonary hypertension. This model demonstrates pathological features of the human disease, including increased right ventricular pressures, medial thickening, neointimal lesion formation, elastin breakdown, increased anastomosis within the bronchial circulation, and perivascular inflammation. Using genetic lineage tracing, clonal analysis, multiplexed in situ hybridization, immunostaining, deep confocal imaging, and staged pharmacological inhibition, we define the cell behaviors underlying each stage of vascular remodeling and identify a pathway required for neointima formation. Results: Neointima arises from smooth muscle cells (SMCs) and not endothelium. Medial SMCs proliferate broadly to thicken the media, after which a small number of SMCs are selected to establish the neointima. These neointimal founder cells subsequently undergoing massive clonal expansion to form occlusive neointimal lesions. The normal pulmonary artery SMC population is heterogeneous, and we identify a Notch3-marked minority subset of SMCs as the major neointimal cell of origin. Notch signaling is specifically required for the selection of neointimal founder cells, and Notch inhibition significantly improves pulmonary artery pressure in animals with pulmonary hypertension. Conclusions: This work describes the first nongenetically driven murine model of pulmonary hypertension (PH) that generates robust and diffuse occlusive neointimal lesions across the pulmonary vascular bed and does so in a stereotyped timeframe. We uncover distinct cellular and molecular mechanisms underlying medial thickening and neointima formation and highlight novel transcriptional, behavioral, and pathogenic heterogeneity within pulmonary artery SMCs. In this model, inflammation is sufficient to generate characteristic vascular pathologies and physiological measures of human PAH. We hope that identifying the molecular cues regulating each stage of vascular remodeling will open new avenues for therapeutic advancements in the treatment of PAH.

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Perspectives on endothelial-to-mesenchymal transition: potential contribution to vascular remodeling in chronic pulmonary hypertension

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00378.2006 ◽

2007 ◽

Vol 293 (1) ◽

pp. L1-L8 ◽

Cited By ~ 202

Author(s):

Enrique Arciniegas ◽

Maria G. Frid ◽

Ivor S. Douglas ◽

Kurt R. Stenmark

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Vascular Remodeling ◽

Serine Proteases ◽

Structural Changes ◽

Transforming Growth Factor ◽

Pulmonary Arteries ◽

Potential Contribution ◽

Mesenchymal Transition ◽

Endothelial Mesenchymal Transition

All forms of pulmonary hypertension are characterized by structural changes in pulmonary arteries. Increased numbers of cells expressing α-smooth muscle (α-SM) actin is a nearly universal finding in the remodeled artery. Traditionally, it was assumed that resident smooth muscle cells were the exclusive source of these newly appearing α-SM actin-expressing cells. However, rapidly emerging experimental evidence suggests other, alternative cellular sources of these cells. One possibility is that endothelial cells can transition into mesenchymal cells expressing α-SM actin and that this process contributes to the accumulation of SM-like cells in vascular pathologies. We review the evidence that endothelial-mesenchymal transition is an important contributor to cardiac and vascular development as well as to pathophysiological vascular remodeling. Recent work has provided evidence for the role of transforming growth factor-β, Wnt, and Notch signaling in this process. The potential roles of matrix metalloproteinases and serine proteases are also discussed. Importantly, endothelial-mesenchymal transition may be reversible. Thus insights into the mechanisms controlling endothelial-mesenchymal transition are relevant to vascular remodeling and are important as we consider new therapies aimed at reversing pulmonary vascular remodeling.

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Upregulation of ET-1 and its receptors and remodeling in small pulmonary veins under hypoxic conditions

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.2001.280.6.l1104 ◽

2001 ◽

Vol 280 (6) ◽

pp. L1104-L1114 ◽

Cited By ~ 30

Author(s):

Hideki Takahashi ◽

Sanae Soma ◽

Masashi Muramatsu ◽

Masahiko Oka ◽

Yoshinosuke Fukuchi

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Vascular Remodeling ◽

Smooth Muscle Actin ◽

Pulmonary Veins ◽

Pulmonary Arteries ◽

Immunohistochemical Method ◽

Muscle Actin ◽

Converting Enzyme ◽

Hypoxic Conditions

Pulmonary veins show greater sensitivity to endothelin (ET)-1-induced vasoconstriction than pulmonary arteries, and remodeling was observed in pulmonary veins under hypoxic conditions. We examined, using an immunohistochemical method, the expression of Big ET-1, ET-converting enzyme (ECE), and ETA and ETB receptors in rat pulmonary veins under normoxic and hypoxic conditions. In control rats, Big ET-1 and ECE were coexpressed in the intima and media of the pulmonary veins, with an even distribution along the axial pathway. ETA and ETB receptors were expressed in the pulmonary veins, with a predominant distribution in the proximal segments. The expression of Big ET-1 was more abundant in the pulmonary veins than in the pulmonary arteries. After exposure to hypoxia for 7 or 14 days, the expression of Big ET-1, ECE, and ET receptors increased in small pulmonary veins. Increases in the medial thickness, wall thickness, and immunoreactivity for α-smooth muscle actin were also observed in the small pulmonary veins under hypoxic conditions. The upregulation of ET-1 and ET receptors in the small pulmonary veins is associated with vascular remodeling, which may lead to the development of hypoxic pulmonary hypertension.

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Regulation of soluble guanylyl cyclase-α1 expression in chronic hypoxia-induced pulmonary hypertension: role of NFATc3 and HuR

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00060.2009 ◽

2009 ◽

Vol 297 (3) ◽

pp. L475-L486 ◽

Cited By ~ 21

Author(s):

Sergio de Frutos ◽

Carlos H. Nitta ◽

Elizabeth Caldwell ◽

Jessica Friedman ◽

Laura V. González Bosc

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Smooth Muscle Cells ◽

Guanylyl Cyclase ◽

Chronic Hypoxia ◽

Pulmonary Arteries ◽

Soluble Guanylyl Cyclase ◽

Muscle Cells ◽

Pulmonary Artery Smooth Muscle

The nitric oxide/soluble guanylyl cyclase (sGC) signal transduction pathway plays an important role in smooth muscle relaxation and phenotypic regulation. However, the transcriptional regulation of sGC gene expression is largely unknown. It has been shown that sGC expression increases in pulmonary arteries from chronic hypoxia-induced pulmonary hypertensive animals. Since the transcription factor NFATc3 is required for the upregulation of the smooth muscle hypertrophic/differentiation marker α-actin in pulmonary artery smooth muscle cells from chronically hypoxic mice, we hypothesized that NFATc3 is required for the regulation of sGC-α1 expression during chronic hypoxia. Exposure to chronic hypoxia for 2 days induced a decrease in sGC-α1 expression in mouse pulmonary arteries. This reduction was independent of NFATc3 but mediated by nuclear accumulation of the mRNA-stabilizing protein human antigen R (HuR). Consistent with our hypothesis, chronic hypoxia (21 days) upregulated pulmonary artery sGC-α1 expression, bringing it back to the level of the normoxic controls. This response was prevented in NFATc3 knockout and cyclosporin (calcineurin/NFATc inhibitor)-treated mice. Furthermore, we identified effective binding sites for NFATc in the mouse sGC-α1 promoter. Activation of NFATc3 increased sGC-α1 promoter activity in human embryonic derived kidney cells, rat aortic-derived smooth muscle cells, and human pulmonary artery smooth muscle cells. Our results suggest that NFATc3 and HuR are important regulators of sGC-α1 expression in pulmonary vascular smooth muscle cells during chronic hypoxia-induced pulmonary hypertension.

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PPARγ regulates hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells through NF-κB

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00090.2010 ◽

2010 ◽

Vol 299 (4) ◽

pp. L559-L566 ◽

Cited By ~ 96

Author(s):

Xianghuai Lu ◽

Tamara C. Murphy ◽

Mark S. Nanes ◽

C. Michael Hart

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Smooth Muscle Cells ◽

Vascular Remodeling ◽

Promoter Activity ◽

Vascular Wall ◽

Pulmonary Artery Smooth Muscle ◽

Human Pulmonary Artery ◽

Stimulation Of

NADPH oxidases are a major source of superoxide production in the vasculature. The constitutively active Nox4 subunit, which is selectively upregulated in the lungs of human subjects and experimental animals with pulmonary hypertension, is highly expressed in vascular wall cells. We demonstrated that rosiglitazone, a synthetic agonist of the peroxisome proliferator-activated receptor-γ (PPARγ), attenuated hypoxia-induced pulmonary hypertension, vascular remodeling, Nox4 induction, and reactive oxygen species generation in the mouse lung. The current study examined the molecular mechanisms involved in PPARγ-regulated, hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells (HPASMC). Exposing HPASMC to 1% oxygen for 72 h increased Nox4 gene expression and H2O2 production, both of which were reduced by treatment with rosiglitazone during the last 24 h of hypoxia exposure or by treatment with small interfering RNA (siRNA) to Nox4. Hypoxia also increased HPASMC proliferation as well as the activity of a Nox4 promoter luciferase reporter, and these increases were attenuated by rosiglitazone. Chromatin immunoprecipitation assays demonstrated that hypoxia increased binding of the NF-κB subunit, p65, to the Nox4 promoter and that binding was attenuated by rosiglitazone treatment. The role of NF-κB in Nox4 regulation was further supported by demonstrating that overexpression of p65 stimulated Nox4 promoter activity, whereas siRNA to p50 or p65 attenuated hypoxic stimulation of Nox4 promoter activity. These results provide novel evidence for NF-κB-mediated stimulation of Nox4 expression in HPASMC that can be negatively regulated by PPARγ. These data provide new insights into potential mechanisms by which PPARγ activation inhibits Nox4 upregulation and the proliferation of cells in the pulmonary vascular wall to ameliorate pulmonary hypertension and vascular remodeling in response to hypoxia.

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Role of 12-lipoxygenase in hypoxia-induced rat pulmonary artery smooth muscle cell proliferation

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00114.2005 ◽

2006 ◽

Vol 290 (2) ◽

pp. L367-L374 ◽

Cited By ~ 61

Author(s):

Ioana R. Preston ◽

Nicholas S. Hill ◽

Rod R. Warburton ◽

Barry L. Fanburg

Keyword(s):

Endothelial Cells ◽

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Protein Expression ◽

Pulmonary Arteries ◽

Mek Inhibitor ◽

Gene And Protein Expression ◽

12 Lipoxygenase

The 12-lipoxygenase (12-LO) pathway of arachidonic acid metabolism stimulates cell growth and metastasis of various cancer cells and the 12-LO metabolite, 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE], enhances proliferation of aortic smooth muscle cells (SMCs). However, pulmonary vascular effects of 12-LO have not been previously studied. We sought evidence for a role of 12-LO and 12(S)-HETE in the development of hypoxia-induced pulmonary hypertension. We found that 12-LO gene and protein expression is elevated in lung homogenates of rats exposed to chronic hypoxia. Immunohistochemical staining with a 12-LO antibody revealed intense staining in endothelial cells of large pulmonary arteries, SMCs (and possibly endothelial cells) of medium and small-size pulmonary arteries and in alveolar walls of hypoxic lungs. 12-LO protein expression was increased in hypoxic cultured rat pulmonary artery SMCs. 12(S)-HETE at concentrations as low as 10−5 μM stimulated proliferation of pulmonary artery SMCs. 12(S)-HETE induced ERK 1/ERK 2 phosphorylation but had no effect on p38 kinase expression as assessed by Western blotting. 12(S)-HETE-stimulated SMC proliferation was blocked by the MEK inhibitor PD-98059, but not by the p38 MAPK inhibitor SB-202190. Hypoxia (3%)-stimulated pulmonary artery SMC proliferation was blocked by both U0126, a MEK inhibitor, and baicalein, an inhibitor of 12-LO. We conclude that 12-LO and its product, 12(S)-HETE, are important intermediates in hypoxia-induced pulmonary artery SMC proliferation and may participate in hypoxia-induced pulmonary hypertension.

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Pulmonary Artery Smooth Muscle Cell Senescence Promotes the Proliferation of PASMCs by Paracrine IL-6 in Hypoxia-Induced Pulmonary Hypertension

Frontiers in Physiology ◽

10.3389/fphys.2021.656139 ◽

2021 ◽

Vol 12 ◽

Author(s):

Ai-Ping Wang ◽

Fang Yang ◽

Ying Tian ◽

Jian-Hui Su ◽

Qing Gu ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Smooth Muscle Cell ◽

Muscle Cell ◽

Vascular Remodeling ◽

Pathophysiological Mechanism ◽

Pulmonary Vascular Remodeling ◽

Pulmonary Artery Smooth Muscle ◽

Active Substances

Pulmonary hypertension (PH) is a critical and dangerous disease in cardiovascular system. Pulmonary vascular remodeling is an important pathophysiological mechanism for the development of pulmonary arterial hypertension. Pulmonary artery smooth muscle cell (PASMC) proliferation, hypertrophy, and enhancing secretory activity are the main causes of pulmonary vascular remodeling. Previous studies have proven that various active substances and inflammatory factors, such as interleukin 6 (IL-6), IL-8, chemotactic factor for monocyte 1, etc., are involved in pulmonary vascular remodeling in PH. However, the underlying mechanisms of these active substances to promote the PASMC proliferation remain to be elucidated. In our study, we demonstrated that PASMC senescence, as a physiopathologic mechanism, played an essential role in hypoxia-induced PASMC proliferation. In the progression of PH, senescence PASMCs could contribute to PASMC proliferation via increasing the expression of paracrine IL-6 (senescence-associated secretory phenotype). In addition, we found that activated mTOR/S6K1 pathway can promote PASMC senescence and elevate hypoxia-induced PASMC proliferation. Further study revealed that the activation of mTOR/S6K1 pathway was responsible for senescence PASMCs inducing PASMC proliferation via paracrine IL-6. Targeted inhibition of PASMC senescence could effectively suppress PASMC proliferation and relieve pulmonary vascular remodeling in PH, indicating a potential for the exploration of novel anti-PH strategies.

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Up-regulation of nPKC Contributes to Proliferation of Pulmonary Artery Smooth Muscle Cells in Hypoxia-induced Pulmonary Hypertension

10.21203/rs.3.rs-135752/v1 ◽

2020 ◽

Author(s):

Yiwei Shi ◽

Rui Jiang ◽

Xiaojiang Qin ◽

Anqi Gao ◽

Xiaomin Hou ◽

...

Keyword(s):

Pulmonary Hypertension ◽

Smooth Muscle ◽

Pulmonary Artery ◽

Smooth Muscle Cells ◽

Magnetic Separation ◽

Muscle Cells ◽

Molecular Therapy ◽

Different Types ◽

Pulmonary Artery Smooth Muscle

Abstract Background It has been indicated that protein kinase C (PKC) plays a vital role in the pathogenesis of hypoxia-induced pulmonary hypertension (PH). The functions or the pathogenic roles of PKCs vary from different types, and their related downstream pathways may also be distinct. Therefore, the specific role of different types of PKC deserves to be elucidated. Discussions regarding conventional PKC (cPKC) have dominated research in recent years, however, the relationship between novel PKC (nPKC) and the development of PH remain unclear. In addition, it is less known whether nPKC has a direct effect on the proliferation of pulmonary artery smooth muscle cells (PASMCs). This study is designed to investigate the role of nPKC in mediating PASMCs proliferation in PH and the underlying mechanisms. Methods Mouse PASMCs was isolated using magnetic separation technology. The PASMCs were divided into 24 h group, 48 h group and 72 h group according to different hypoxia treatment time, then detected cell proliferation rate and nPKC expression level in each group. We treated PASMCs with agonists or inhibitors of PKCδ and PKCε and exposed them to hypoxia or normoxia for 72 h, then measured the proliferation of PASMCs. We also constructed a lentiviral vector containing siRNA fragments for inhibiting PKCδ and PKCε to transfected PASMCs, then examined their proliferation. Results PASMCs isolated successfully by magnetic separation method and were in good condition. Hypoxia promoted the proliferation of PASMCs, and the treatment for 72 h had the most significant effect. Hypoxia upregulated the expression of PKCδ and PKCε in mouse PASMCs, leading to PASMCs proliferation. Moreover, Our study demonstrated that hypoxia induced upregulation of PKCδ and PKCε expression resulting to the proliferation of PASMCs via up-regulating the phosphorylation of AKT and ERK. Conclusions Our study provides clear evidence that increased nPKC expression contributes to PASMCs proliferation and uncovers the correlation between AKT and ERK pathways and nPKC-mediated proliferation of PASMCs. These findings may provide novel targets for molecular therapy of pulmonary hypertension.

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