Insulin Growth Factor-Induced Pulmonary Artery Smooth Muscle Cell Proliferation In Patients With Pulmonary Arterial Hypertension

Author(s):  
Laurence Dewachter ◽  
Celine Dewachter ◽  
Benoit Rondelet ◽  
Myriam Remmelinck ◽  
Jean-Luc Vachiery ◽  
...  
2021 ◽  
Vol 12 ◽  
Author(s):  
Yong-Jie Chen ◽  
Yi Li ◽  
Xian Guo ◽  
Bo Huo ◽  
Yue Chen ◽  
...  

Abnormal proliferation of pulmonary artery smooth muscle cells (PASMCs) is a critical pathological feature in the pathogenesis of pulmonary arterial hypertension (PAH), but the regulatory mechanisms remain largely unknown. Herein, we demonstrated that interferon regulatory factor 9 (IRF9) accelerated PASMCs proliferation by regulating Prohibitin 1 (PHB1) expression and the AKT-GSK3β signaling pathway. Compared with control groups, the rats treated with chronic hypoxia (CH), monocrotaline (MCT) or sugen5416 combined with chronic hypoxia (SuHx), and mice challenged with CH had significantly thickened pulmonary arterioles and hyperproliferative PASMCs. More importantly, the protein level of IRF9 was found to be elevated in the thickened medial wall of the pulmonary arterioles in all of these PAH models. Notably, overexpression of IRF9 significantly promoted the proliferation of rat and human PASMCs, as evidenced by increased cell counts, EdU-positive cells and upregulated biomarkers of cell proliferation. In contrast, knockdown of IRF9 suppressed the proliferation of rat and human PASMCs. Mechanistically, IRF9 directly restrained PHB1 expression and interacted with AKT to inhibit the phosphorylation of AKT at thr308 site, which finally led to mitochondrial dysfunction and PASMC proliferation. Unsurprisingly, MK2206, a specific inhibitor of AKT, partially reversed the PASMC proliferation inhibited by IRF9 knockdown. Thus, our results suggested that elevation of IRF9 facilitates PASMC proliferation by regulating PHB1 expression and AKT signaling pathway to affect mitochondrial function during the development of PAH, which indicated that targeting IRF9 may serve as a novel strategy to delay the pathological progression of PAH.


2021 ◽  
Vol 41 (3) ◽  
pp. 1205-1217 ◽  
Author(s):  
Ryo Kurosawa ◽  
Kimio Satoh ◽  
Takashi Nakata ◽  
Tomohiko Shindo ◽  
Nobuhiro Kikuchi ◽  
...  

Objective: Pulmonary arterial hypertension is characterized by abnormal proliferation of pulmonary artery smooth muscle cells and vascular remodeling, which leads to right ventricular (RV) failure. Bsg (Basigin) is a transmembrane glycoprotein that promotes myofibroblast differentiation, cell proliferation, and matrix metalloproteinase activation. CyPA (cyclophilin A) binds to its receptor Bsg and promotes pulmonary artery smooth muscle cell proliferation and inflammatory cell recruitment. We previously reported that Bsg promotes cardiac fibrosis and failure in the left ventricle in response to pressure-overload in mice. However, the roles of Bsg and CyPA in RV failure remain to be elucidated. Approach and Results: First, we found that protein levels of Bsg and CyPA were upregulated in the heart of hypoxia-induced pulmonary hypertension (PH) in mice and monocrotaline-induced PH in rats. Furthermore, cardiomyocyte-specific Bsg-overexpressing mice showed exacerbated RV hypertrophy, fibrosis, and dysfunction compared with their littermates under chronic hypoxia and pulmonary artery banding. Treatment with celastrol, which we identified as a suppressor of Bsg and CyPA by drug screening, decreased proliferation, reactive oxygen species, and inflammatory cytokines in pulmonary artery smooth muscle cells. Furthermore, celastrol treatment ameliorated RV systolic pressure, hypertrophy, fibrosis, and dysfunction in hypoxia-induced PH in mice and SU5416/hypoxia-induced PH in rats with reduced Bsg, CyPA, and inflammatory cytokines in the hearts and lungs. Conclusions: These results indicate that elevated Bsg in pressure-overloaded RV exacerbates RV dysfunction and that celastrol ameliorates RV dysfunction in PH model animals by suppressing Bsg and its ligand CyPA. Thus, celastrol can be a novel drug for PH and RV failure that targets Bsg and CyPA. Graphic Abstract: A graphic abstract is available for this article.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Thomas E Stephens ◽  
Elena Arons ◽  
Ying-Yi Zhang ◽  
Paula Zaman ◽  
Reza Aghamohammadzadeh ◽  
...  

In pulmonary arterial hypertension (PAH), elevated levels of aldosterone (ALDO) induce a vasculopathy that is characterized by dysregulated pulmonary artery smooth muscle cell (PSMC) growth. Upregulation of the mammalian target of rapamycin complex 1 subunit Raptor induces PSMC growth; however, the factors regulating Raptor in PAH are not known. We hypothesized that Raptor activation by ALDO induces PSMC proliferation, hypertrophic vascular remodeling, and PAH. To test this hypothesis, PSMCs were exposed to vehicle (V) control or ALDO (10 -7 mol/l) for 1 h. Compared to V-treated cells, ALDO increased expression of P-Raptor(Ser792) and the Raptor target P-p70S6K(Thr389) by 68% (P<0.01) and 50% (P<0.01), respectively, without affecting total Raptor/p70S6K levels. Raptor upregulation in ALDO-treated cells also increased PSMC proliferation by 19% (P<0.01), assessed by BrdU incorporation. To explore the relevance of ALDO-Raptor signaling in vivo , we studied the monocrotaline (MCT) model of PAH, which is characterized by hyperALDO. In a prevention protocol, MCT-PAH rats were treated with spironolactone (SP)(25 mg/kg/d) in the drinking water to inhibit ALDO and/or intravenous Staramine-mPEG labeled with Raptor-siRNA (2 mg/kg dose x4)(si-Raptor). Anti-Raptor and anti-α-SM actin immunohistochemistry showed that compared to controls (N=4), Raptor expression and vessel thickness was increased in MCT-PAH rats (N=5) by 87% (P<0.01) and 5.8-fold (P<0.01), respectively, and pulmonary artery systolic pressure (PASP) was increased significantly (25 ± 4 vs. 77 ± 12 mmHg, P<0.01) as assessed by catheterization. Compared to MCT-PAH, MCT-si-Raptor (N=5) decreased Raptor levels by 31% (P<0.05), arteriole thickness by 41% (P<0.05), and PASP (77 ± 12 vs. 46 ± 5 mmHg, P<0.05) without affecting central blood pressure significantly. A further benefit was observed in MCT-si-Raptor+SP rats (N=5) for arterial thickness (-57%, P<0.01) and PASP (46 ± 5 vs. 39 ± 5 mmHg, P<0.05) compared to MCT-si-Raptor. Taken together, Raptor activation by ALDO induces PSMC proliferation in vitro to promote PAH in vivo . Identifying ALDO-Raptor signaling as a pathobiological mechanism underlying pulmonary vascular remodeling may have novel therapeutic implications for PAH patients.


2017 ◽  
Vol 96 (2) ◽  
pp. 223-235 ◽  
Author(s):  
Alice Bourgeois ◽  
Caroline Lambert ◽  
Karima Habbout ◽  
Benoit Ranchoux ◽  
Stéphanie Paquet-Marceau ◽  
...  

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