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

2007 ◽  
Vol 293 (1) ◽  
pp. L1-L8 ◽  
Author(s):  
Enrique Arciniegas ◽  
Maria G. Frid ◽  
Ivor S. Douglas ◽  
Kurt R. Stenmark

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.

2021 ◽  
Vol 22 (9) ◽  
pp. 4980
Author(s):  
Inés Roger ◽  
Javier Milara ◽  
Paula Montero ◽  
Julio Cortijo

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.


1995 ◽  
Vol 79 (4) ◽  
pp. 1163-1172 ◽  
Author(s):  
J. R. Gossage ◽  
E. A. Perkett ◽  
J. M. Davidson ◽  
B. C. Starcher ◽  
D. Carmichael ◽  
...  

Continuous air embolization (CAE) into the pulmonary arterial circulation of sheep results in functional and structural changes of chronic pulmonary hypertension. Release of elastin peptides into lung lymph during CAE and attenuation of CAE-induced pulmonary hypertension by neutrophil depletion suggest that neutrophil elastase may contribute to these changes. To investigate this notion, we treated awake sheep with a potent neutrophil elastase inhibitor, recombinant secretory leukoprotease inhibitor (SLPI) (100 mg/day by aerosol), during 12 days of CAE (CAE+SLPI; n = 7). Controls included sheep receiving CAE + vehicle (VEH) (n = 6), VEH alone (n = 3), and SLPI alone (n = 3). SLPI significantly attenuated the CAE-induced increases in lung lymph flow (day 8; 2.3 +/- 0.5 vs. 5.6 +/- 1.7 ml/15 min), protein clearance (day 8; 1.36 +/- 0.32 vs. 3.08 +/- 0.84 ml/15 min), and elastin peptide concentration (day 8; 243 +/- 41 vs. 398 +/- 44 ng/ml). SLPI delayed the onset of sustained pulmonary hypertension from day 8 to day 12. Both CAE groups showed similar structural changes in the pulmonary arteries. SLPI was well tolerated in control sheep and did not affect hemodynamics or structure. We conclude that serine proteases may contribute to the early initiation of chronic pulmonary hypertension but do not play a striking role in its eventual development.


2001 ◽  
Vol 280 (6) ◽  
pp. L1104-L1114 ◽  
Author(s):  
Hideki Takahashi ◽  
Sanae Soma ◽  
Masashi Muramatsu ◽  
Masahiko Oka ◽  
Yoshinosuke Fukuchi

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.


1995 ◽  
Vol 79 (2) ◽  
pp. 589-593 ◽  
Author(s):  
J. A. Madden ◽  
P. A. Keller ◽  
J. S. Choy ◽  
T. A. Alvarez ◽  
A. D. Hacker

To determine whether altered NO production contributes to attenuated distensibility (alpha), vasoreactivity, and acetylcholine (ACh) dilation in pulmonary arteries from monocrotaline (MCT)-treated rats (J.A. Madden, P.A. Keller, R. M. Effrosa, C. Sequitte, J.S. Choy, and A.D. Hacker. J. Appl. Physiol. 76: 1589–1593, 1994), intralobar and sidebranch arteries from rats 21 days after MCT treatment were cannulated and pressurized and their diameter changes in response to KCl, norepinephrine, angiotensin II, and pressure were measured in the presence of N omega-nitro-L-arginine (NLA) and L-arginine. NLA treatment decreased MCT artery diameters more than normal arteries (P < 0.05) and abolished ACh dilation in both. Agonist responses were greater in normal but not MCT arteries. The alpha increased in NLA-treated normal (P < 0.05) but not MCT arteries. After L-arginine, normal and MCT arteries returned to control diameters and dilated to ACh. Agonist responses returned to control in normal but not MCT arteries. Normal but not MCT arteries dilated in calcium-free solution (P < 0.05). These results suggest that pulmonary arteries from rats with MCT-induced pulmonary hypertension produce more NO than do pulmonary arteries; inhibiting NO does not increase contractility; and decreased vasoreactivity and alpha values are not due to smooth muscle cell tone but may be due to abnormal vascular remodeling.


2003 ◽  
Vol 284 (5) ◽  
pp. L826-L833 ◽  
Author(s):  
Vivek Balasubramaniam ◽  
Timothy D. Le Cras ◽  
D. Dunbar Ivy ◽  
Theresa R. Grover ◽  
John P. Kinsella ◽  
...  

Platelet-derived growth factor (PDGF) is a potent smooth muscle cell mitogen that may contribute to smooth muscle hyperplasia during the development of chronic pulmonary hypertension (PH). We studied changes in PDGFα- and β-receptor and ligand expression in lambs with chronic intrauterine PH induced by partial ligation of the ductus arteriosus (DA) at gestational age 124–128 days (term = 147 days). Western blot analysis performed on whole lung homogenates from PH animals after 8 days of DA ligation showed a twofold increase in PDGFα- and β-receptor proteins compared with age-matched controls ( P < 0.05). Lung PDGF-A and -B mRNA expression did not differ between PH and control animals. We treated PH animals with NX1975, an aptamer that selectively inhibits PDGF-B, by infusion into the left pulmonary artery for 7 days after DA ligation. NX1975 reduced the development of muscular thickening of small pulmonary arteries by 47% ( P < 0.05) and right ventricular hypertrophy (RVH) by 66% ( P < 0.02). Lung PDGFα- and β-receptor expression is increased in perinatal PH, and NX1975 reduces the increase in wall thickness of small pulmonary arteries and RVH in this model. We speculate that PDGF signaling contributes to structural vascular remodeling in perinatal PH and that selective PDGF inhibition may provide a novel therapeutic strategy for the treatment of chronic PH.


Circulation ◽  
2020 ◽  
Vol 142 (16) ◽  
pp. 1545-1561
Author(s):  
Lea C. Steffes ◽  
Alexis A. Froistad ◽  
Adam Andruska ◽  
Mario Boehm ◽  
Madeleine McGlynn ◽  
...  

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.


2019 ◽  
Author(s):  
Takeo Tsutsumi ◽  
Tetsutaro Nagaoka ◽  
Takashi Yoshida ◽  
Lei Wang ◽  
Sachiko Kuriyama ◽  
...  

AbstractNeointimal lesion and medial wall thickness of pulmonary arteries (PAs) are common pathological findings in pulmonary arterial hypertension (PAH). Platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) signaling contribute to intimal and medial vascular remodeling in PAH. Nintedanib is a tyrosine kinase inhibitor whose targets include PDGF and FGF receptors. Although the beneficial effects of nintedanib were demonstrated for human idiopathic pulmonary fibrosis, its efficacy for PAH is still unclear. Thus, we hypothesized that nintedanib is a novel treatment for PAH to inhibit the progression of vascular remodeling in PAs. The inhibitory effects of nintedanib were evaluated both in endothelial mesenchymal transition (EndMT)-induced human pulmonary microvascular endothelial cells (HPMVECs) and human pulmonary arterial smooth muscle cells (HPASMCs) stimulated by growth factors. We also tested the effect of chronic nintedanib administration on a PAH rat model induced by Sugen5416 (a VEGF receptor inhibitor) combined with chronic hypoxia. Nintedanib was administered from weeks 3 to 5 after Sugen5416 injection, and pulmonary hemodynamics and PAs pathology were evaluated. Nintedanib attenuated the expression of mesenchymal markers in EndMT-induced HPMVECs and HPASMCs proliferation. Phosphorylation of PDGF and FGF receptors was augmented both in both intimal and medial lesions of PAs. Nintedanib blocked these phosphorylation, improved hemodynamics and reduced vascular remodeling involving neointimal lesions and medial wall thickening in PAs. Additionally, expressions Twist1, transcription factors associated with EndMT, in lung tissue was significantly reduced by nintedanib. These results suggest that nintedanib may be a novel treatment for PAH with anti-vascular remodeling effects.


2009 ◽  
Vol 106 (4) ◽  
pp. 1356-1364 ◽  
Author(s):  
Arne Yndestad ◽  
Karl-Otto Larsen ◽  
Erik Øie ◽  
Thor Ueland ◽  
Camilla Smith ◽  
...  

Activin A, a member of the transforming growth factor (TGF)-β superfamily, is involved in regulation of tissue remodeling and inflammation. Herein, we wanted to explore a role for activin A in pulmonary hypertension (PH). Circulating levels of activin A and its binding protein follistatin were measured in patients with PH ( n = 47) and control subjects ( n = 14). To investigate synthesis and localization of pulmonary activin A, we utilized an experimental model of hypoxia-induced PH. In mouse lungs, we also explored signaling pathways that can be activated by activin A, such as phosphorylation of Smads, which are mediators of TGF-β signaling. Possible pathophysiological mechanisms initiated by activin A were explored by exposing pulmonary arterial smooth muscle cells in culture to this cytokine. Elevated levels of activin A and follistatin were found in patients with PH, and activin A levels were significantly related to mortality. Immunohistochemistry of lung autopsies from PH patients and lungs with experimental PH localized activin A primarily to alveolar macrophages and bronchial epithelial cells. Mice with PH exhibited increased pulmonary levels of mRNA for activin A and follistatin in the lungs, and also elevated pulmonary levels of phosphorylated Smad2. Finally, we found that activin A increased proliferation and induced gene expression of endothelin-1 and plasminogen activator inhibitor-1 in pulmonary artery smooth muscle cells, mediators that could contribute to vascular remodeling. Our findings in both clinical and experimental studies suggest a role for activin A in the development of various types of PH.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Megan F Burke ◽  
Caitlin O’Rourke ◽  
Trejeeve Martyn ◽  
Hannah R Shakartzi ◽  
Timothy E Thayer ◽  
...  

Background: Matrix Gla protein (MGP) is an extracellular matrix protein that inhibits bone morphogenetic protein (BMP) signaling in vitro. MGP deficiency induces vascular calcification associated with osteogenic transdifferentiation of endothelial cells (via endothelial-mesenchymal transition, EndMT) and vascular smooth muscle cells (VSMCs). We previously reported that treatment with two pharmacologic inhibitors of BMP signaling reduced aortic calcification in MGP-/- mice. We hypothesized that BMP signaling is essential for EndMT and VSMC osteogenic transdifferentiation induced by MGP deficiency. Methods and Results: Aortic levels of mRNAs encoding markers of osteogenesis (Runx2 and osteopontin) and EndMT (nanog, Sox2, and Oct3/4) were greater in MGP-/- than in wild-type mice (P<0.01 for all). Aortic expression of markers of VSMC differentiation (α-smooth muscle actin, transgelin, and calponin) was less in MGP-/- than in wild-type mice (P<0.001 for all). Treatment of MGP-/- mice with the BMP signaling inhibitor, LDN-193189, reduced expression of both osteogenic and EndMT markers (P<0.05 for all) but did not prevent VSMC de-differentiation. Depletion of MGP in cultured wild-type VSMCs with siRNA specific for MGP (siMGP) was associated with a 30-40% reduction in levels of mRNAs encoding markers of VSMC differentiation (P<0.05 for all), an effect that was not prevented by LDN-193189. Incubation in phosphate-containing media induced greater calcification in siMGP-treated VSMCs than in cells treated with control siRNA (P<0.0001). Treatment with LDN-193189 reduced calcification in siMGP-treated VSMCs (50%, P=0.0003). Conversely, infection of MGP-/- VSMCs with adenovirus specifying MGP increased expression of markers of VSMC differentiation by 60-80% (P<0.01 for all) and decreased calcification by 74% (P=0.03). Conclusions: Inhibition of BMP signaling suppresses osteogenic and EndMT gene programs in MGP-/- mice and reduces calcification of siMGP-treated VSMCs. However, MGP deficiency induces VSMC de-differentiation via a BMP-independent mechanism. These findings suggest that the processes underlying vascular calcification in MGP deficiency are mediated by both BMP signaling-dependent and -independent mechanisms.


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