Lung-specific RNA interference of coupling factor 6, a novel peptide, attenuates pulmonary arterial hypertension in rats.

Jing Yin ,Shuling You,Shouhai Jiao,Hesheng Hu,Xiaolu Li,Nannan Li,Min Xu,Ju Liu,Mei Xue,Ye Wang,Wen-Chieh Cheng ,Shi Fang Yan

doi:10.1186/s12931-016-0409-5

Abstract

BackgroundPulmonary arterial hypertension (PAH) is a progressive and life-threatening disease associated with high morbidity and mortality rates. However, the exact regulatory mechanism of PAH is unknown. Although coupling factor 6 (CF6) is known to function as a repressor, its role in PAH has not been explored. Here, we investigated the involvement of endogenous CF6 in the development of PAH.MethodsPAH was induced with monocrotaline (MCT), as demonstrated by significant increases in pulmonary artery pressure and vessel wall thickness. The adeno-associated virus (AAV) carrying CF6 short hairpin RNA (shRNA) or control vector (2×1010 gp) was intratracheally transfected into the lungs of rats 2 weeks before or after MCT injection.ResultsA 2-6-fold increase in CF6 was observed in the lungs and circulation of the MCT-injected rats as confirmed by qRT-PCR and ELISA. Immunohistochemistry analysis revealed a small quantity of CF6 localized to endothelial cells (ECs) under physiological conditions spread to surrounding tissues in a paracrine manner in PAH lungs. Notably, CF6 shRNA effectively inhibited CF6 expression, abolished lung macrophage infiltration, reversed endothelial dysfunction and vascular remodeling, and ameliorated the severity of pulmonary hypertension and right ventricular dysfunction at 4 weeks both as a pretreatment and rescue intervention. In addition, the circulating and lung levels of 6-keto-PGF1a, a stable metabolite of prostacyclin, were reversed by CF6 inhibition, suggesting that the effect of CF6 inhibition may partly be mediated through prostacyclin.ConclusionsCF6 contributes to the pathogenesis of PAH, probably in association with downregulation of prostacyclin. The blockage of CF6 might be applied as a novel therapeutic approach for PAH and PA remodeling.Electronic supplementary materialThe online version of this article (doi:10.1186/s12931-016-0409-5) contains supplementary material, which is available to authorized users.

Highlights

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease associated with high morbidity and mortality rates
High death rates were observed among the PAH rats at 4 weeks after MCT injection; no control rats died during the experimental period
Our results showed that the Green fluorescent protein (GFP) was expressed in lung tissues, indicating that the short hairpin RNA (shRNA) complex could be efficiently delivered to lungs in vivo via intratracheal injection (Fig. 3a)

Summary

Introduction

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease associated with high morbidity and mortality rates. Yin et al Respiratory Research (2016) 17:99 from the surface of vascular endothelial cells by mechanical forces such as the tumor necrosis factor-alpha (TNF-α), shear stress, and high glucose levels [8, 9]. Studies showed that plasma membranebound ATP synthase in the vascular endothelial cells functions as a receptor for CF6 and may play an important role in affecting vascular function by increasing the concentration of intracellular proton, acidosis [10]. In CF6-overexpressing transgenic mice, endothelial dysfunction increases, and wall thickness and inflammation are increased in small vessels [11]. These data suggests that CF6, which directly inhibits PGI2 synthase, may be present in pulmonary arteries and function as a novel target in the treatment of PAH

Objectives

Methods

Results

Discussion

Conclusion