miR-210-5p Promotes Pulmonary Hypertension by Blocking ATP2A2.

AIM: Aberrant expression of ATPase sarcoplasmic/endoplasmic retic Ca2+ transporting 2 (ATP2A2) has attracted attention for its pathophysiologic role in pulmonary hypertension (PH). Several miRNAs, including miR-210-5p, have also been reported to be pathogenic factors in PH, but their exact mechanisms remain unknown. This study aimed to elucidate the potential mechanisms of miR-210-5p and ATP2A2 in MCT-induced PH. METHODS: Eighteen Sprague-Dawley rats were randomly divided into two groups-monoclonal (MCT) group and control group-and then administered MCT (60 mg/kg) and saline, respectively. mPAP, PVR, RVHI, WT%, and WA% were significantly increased in PH rats after 3 weeks, confirming that the modeling of PH rats was successful. Subsequently, we determined the expression of ATP2A2 and miR-210-5p in lung tissues using WB and qRT-PCR methods. We established an in vitro model using BMP4 and TGF-ß1 treatment of pulmonary artery smooth muscle cells (PASMCs) and examined the expression of ATP2A2 and miR-210-5p using the same method. To further elucidate the regulatory relationship between ATP2A2 and miR-210-5p, we altered the expression level of miR-210-5p and detected the corresponding changes in ATP2A2 levels. In addition, we demonstrated the relationship by dual luciferase experiments. Finally, the effect of silencing ATP2A2 could be confirmed by the level of cell membrane Ca2+ in PAMSCs. RESULTS: Up-regulation of miR-210-5p and down-regulation of ATP2A2 were observed in the MCT group compared with the control group, which was confirmed in the in vitro model. In addition, elevated miR-210-5p expression decreased the level of ATP2A2 while increasing the proliferation of PASMCs, and the results of the dual luciferase assay further confirmed that ATP2A2 is a downstream target of miR-210-5p. Additionally, silencing ATP2A2 resulted in increased cytoplasmic Ca2+ levels in PAMSCs. CONCLUSION: In MCT-induced PH, miR-210-5p promotes pulmonary vascular remodeling by inhibiting ATP2A2.

Grape seed procyanidin suppresses inflammation in cigarette smoke-exposed pulmonary arterial hypertension rats by the PPAR-γ/COX-2 pathway.

BACKGROUND AND AIM: Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling, which is mainly caused by inflammation. Inhibiting inflammation can relieve PAH. Grape seed procyanidin (GSP) possesses remarkable anti-inflammatory property and vascular protective function. In this experiment, we verified the anti-inflammatory property of GSP in cigarette smoke-exposed PAH rats and revealed its molecular mechanism. METHODS AND RESULTS: In vivo, 45 Sprague Dawley (SD) rats were divided into 5 groups randomly, treated with normoxia/cigarette smoke (CS)/GSP + CS/CS + solvent/GSP. After GSP + CS administration, a decrease in mPAP, PVR, RVHI, WT%, and WA% was detected in the rats as compared to those treated with CS. In vitro, the proliferation of pulmonary arterial smooth muscle cells (PASMCs) caused by cigarette smoke extract (CSE) was effectively attenuated with GSP + CSE administration. Furthermore, GSP significantly increased the expression of peroxisome proliferator-activated receptor γ (PPAR-γ) together with the lowered expression level of cyclooxygenase 2 (COX-2) in PASMCs co-incubated with CSE. CONCLUSION: These findings indicate that GSP ameliorates inflammation by the PPAR-γ/COX-2 pathway and finally inhibits the proliferation of PASMCs, which leads to pulmonary vascular remodeling.

[Effects of apple polyphenols on monocrotaline-induced pulmonary vascular remodeling in rats and its mechanism].

OBJECTIVE: To investigate the effects of apple polyphenols on pulmonary vascular remodeling in rats with pulmonary arterial hypertension and its mechanism. METHODS: Rats were randomly divided into 4 groups:control (Con) group, monocrotaline (MCT) group, apple polyphenol (APP) group,monocrotaline + apple polyphenol (MCT+APP) group. In Con group, rats received a subcutaneous injection of physical saline. In APP group, rats received intraperitoneal injection of 20 mg/kg APP, every other day. In MCT group, rats received a single subcutaneous injection of MCT(60 mg/kg). In MCT+APP group, rats received subcutaneous injection of 60 mg/kg MCT followed by an intraperitoneal injection of 20 mg/kg APP every other day. All the disposal lasted 3 weeks. Then the PAH-relevant indicators, such as mean pulmonary artery pressure(mPAP), pulmonary vascular resistance(PVR), right ventricular hypertrophy index (RVHI) ,wall thickness (WT%) and wall area (WA%) were tested. After that, the inflammatory pathway related indicators, such as interleukin1(IL-1),interleukin1(IL-6), tumor necrosis factor α(TNF-α), cyclooxygenase 2(COX-2) and myeloperoxidase(MPO) in pulmonary tissue and free intracellular Ca2+ in pulmonary smooth muscle cell(PASMC), content of eNOS and NO in endothelial cells were determined. RESULTS: Compared with the control group, the levels of mPAP, PVR, RVHI, WA%, WT%, and IL-1, IL-6, TNF-α, COX-2, MPO in tissue and the expression of Ca2 + in PASMC of MCT group were increased significantly, while the contents of eNOS and NO in endothelial cells were decreased significantly (P＜0.05). Compared with the MCT group, the apple polyphenol treatment could improve the above mentioned situation, and the COX-2 and Ca2+ indicators of the apple polyphenol treatment group were decreased significantly (P＜0.05). CONCLUSION: MCT can increase COX-2 expression and intracellular Ca2+ in pulmonary artery smooth muscle cells, decrease the contents of eNOS and NO in endothelial cells, while apple polyphenols can significantly inhibit these effects.