Plasminogen activator Inhibitor-2 inhibits pulmonary arterial smooth muscle cell proliferation in pulmonary arterial hypertension via PI3K/Akt and ERK signaling

https://doi.org/10.1016/j.yexcr.2020.112392Get rights and content

Highlights

  • Serum PAI-2 is decreased in patients with pulmonary arterial hypertension.

  • Serum PAI-2 is associated with disease severity in pulmonary arterial hypertension.

  • Exogenous PAI-2 attenuates monocrotaline induced pulmonary hypertension in rats.

  • PAI-2 inhibits pulmonary arterial smooth muscle proliferation via PI3K/Akt and ERK.

Abstract

Background

The proliferation of pulmonary arterial smooth muscle cells (PASMCs) and subsequent pulmonary vascular remodeling leads to pulmonary arterial hypertension (PAH). Understanding the underlying mechanisms and identifying molecules that can suppress PASMCs proliferation is critical for developing effective pharmacological treatment. We previously showed that plasminogen activator inhibitor-2 (PAI-2) inhibited human PASMC (hPASMCs) proliferation in vitro. However, its inhibitory effect on PAH remains to be determined, and the mechanism remains to be illustrated.

Methods

We compared serum PAI-2 levels between PAH patients and healthy controls, and examined the correlation between PAI-2 level and disease severity. In monocrotaline-induced PAH rats, we examined the effects of exogenous PAI-2 administration on pulmonary vascular remodeling and PAH development. The effect of PAI-2 and potential mechanisms was further examined in cultured hPASMCs.

Results

The serum PAI-2 was decreased in PAH patients compared with controls. PAI-2 level was negatively correlated with mean pulmonary arterial pressure and estimated systolic pulmonary arterial pressure in ultrasonic cardiogram, while positively correlated with 6-min walking distance. In rats, administration of exogenous PAI-2 significantly reversed monocrotaline-induced PAH, as indicated by the decrease in right ventricle systolic pressure, right ventricular hypertrophy index and percent media thickness of pulmonary arterioles. Further mechanistic investigation in hPASMCs showed that PAI-2 inhibited cell proliferation by preventing the activation of PI3K/Akt and ERK pathways.

Conclusion

PAI-2 is downregulated in PAH patients. PAI-2 attenuates PAH development by suppressing hPASMCs proliferation via the inhibition of PI3K/Akt and ERK pathways. PAI-2 may serve as a potential biomarker and therapeutic target for PAH.

Section snippets

Background

Pulmonary arterial hypertension (PAH) shares characteristics similar with malignant diseases, such as the overproliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs) [1,2]. Pulmonary vascular remodeling, characterized by medial hypertrophy, intimal proliferative changes, adventitial thickening, complex lesions and thrombotic lesions, is the major pathological change of PAH [3]. The enhanced proliferation and reduced apoptosis of the PASMCs in the medial layer

Cell culture

hPASMCs isolated from healthy human pulmonary arteries were from ScienCell Research Laboratories (Carlsbad, CA, USA), and characterized by immune-fluorescent method with antibodies to α-smooth muscle actin and desmin. hPASMCs were cultured in smooth muscle cell medium (ScienCell Research Laboratories, Carlsbad, CA, USA) supplemented with 2% fetal bovine serum and 1% smooth muscle cell growth supplement, enriched at 37 °C in a 5% CO2 atmosphere. Passages three to six were used for transfection.

Overexpression and knock-down of PAI-2 in hPASMCs

Serum PAI-2 is decreased in PAH patients

We first examined serum PAI-2 level in patients with PAH. Fifty PAH patients and fifty healthy controls were enrolled in this study. Thirteen patients were diagnosed with idiopathic PAH (IPAH), 24 with connective tissue disease-associated PAH (CTD-PAH), 8 with congenital heart disease-associated PAH (CHD-PAH), 1 with portal hypertension-PAH and 4 with pulmonary veno-occlusive disease (PVOD)/pulmonary capillary hemangiomatosis (PCH). The median age of PAH patients was 36 years old and 74% of

Discussion

In this study, we observed that the serum PAI-2 was decreased in PAH patients compared with healthy controls, and PAI-2 level was negatively correlated with mPAP and eSPAP in ultrasonic cardiogram while positively correlated with 6MWD in PAH patients. In rats, administration of exogenous PAI-2 significantly reversed monocrotaline-induced PAH, as indicated by the decrease of RVSP, RVHI and %MT of pulmonary arterioles. Mechanistically, PAI-2 inhibited hPASMCs proliferation by preventing the

Conflict of interest form

No conflicts of interest, financial or otherwise, are declared by the authors.

CRediT authorship contribution statement

Shuai Zhang: Conceptualization, Methodology, Software, Formal analysis, Investigation, Data curation, Writing - original draft, Project administration, Funding acquisition. Jing Wang: Software, Validation, Investigation, Resources, Data curation. Xianmei Qi: Methodology, Investigation, Resources. Xincao Tao: Investigation, Resources. Wanmu Xie: Resources, Writing - review & editing. Jun Wan: Investigation, Resources, Writing - review & editing. Ying H. Shen: Writing - review & editing,

Acknowledgments

This work was supported by the National Natural Science Foundation of China (No. 81600036 and 81570049), CAMS Innovation Fund for Medical Sciences (CIFMS) (No. 2018-I2M-1-003) and the Fund of the National Key Research and Development Program of China (No. 2016YFC0905600).

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