Background/Aims: Pulmonary arterial hypertension (PAH) is a severe and debilitating disease characterized by remodeling of the pulmonary vessels, which is driven by excessive proliferation and migration and apoptosis resistance in pulmonary artery smooth muscle cells (PASMCs). The calcineurin (CaN)/nuclear factor of activated T-cells (NFAT) signaling pathway is the most important downstream signaling pathway of store-operated Ca²⁺ entry (SOCE), which is increased in PAH. CaN/NFAT has been reported to contribute to abnormal proliferation in chronic hypoxia (CH)-induced PAH. However, the effect of CaN/NFAT signaling on PASMC proliferation, migration and apoptosis in monocrotaline (MCT)-induced PAH remains unclear. Methods: PAH rats were established by a single intraperitoneal injection of MCT for 21 days. PASMCs were isolated and cultured in normal and MCT-induced PAH Sprague-Dawley rat. PASMCs were treated with CsA targeting CaN and siRNA targeting NFATc2-4 gene respectively by liposome. We investigated the expression of calcineurin/NFAT signaling by immunofluorescence, qRT-PCR and Western blotting methods. Cell proliferation was monitored using MTS reagent or by assessing proliferating cell nuclear antigen (PCNA) expression. Cell apoptosis was evaluated with an Annexin V - FITC/propidium iodide (PI) apoptosis kit by flow cytometry. PASMC migration was assessed with a Transwell chamber. Results: MCT successfully induced PAH and pulmonary vascular remodeling in rats. CaN phosphatase activity and nuclear translocation of NFATc2-4 were increased in PASMCs derived from MCT-treated rats. In addition, CaNBβ/NFATc2-4 expression was amplified at the mRNA and protein levels. PASMC proliferation and migration were markedly inhibited in a dosedependent manner by cyclosporin A (CsA). Furthermore, siRNA targeting NFATc2 and NFATc4 attenuated the excessive proliferation and migration and apoptosis resistance in PASMCs derived from both CON and MCT-treated rats, while NFATc3 knockdown specifically affected MCT-PASMCs. Conclusion: Our results demonstrate that CaN/NFAT signaling is activated and involved in the modulation of PASMC proliferation, migration and apoptosis in MCT-induced PAH.

Background: Daunorubicin (DNR)-induced cardiotoxicity, which is closely associated with cardiomyocyte apoptosis, limits the drug's clinical application. The activation of the extracellular regulated protein kinases (ERKs) pathway is responsible for the pro-apoptosis effect of DNR Sodium ferulate (SF) has recently been found to attenuate both DNR-induced cardiotoxicity and mitochondrial apoptosis in juvenile rats. Nonetheless, the precise mechanism underlying SF-induced cardio-protection remains unclear. Methods: The DNR-injured H9c2 cell model was prepared by incubating the cells in 1 µM DNR for 24 h. Amounts of 15.6, 31.3 or 62.5 µM SF were simultaneously added to the cells. The effect of SF on the cytotoxic and apoptotic parameters of the cells was studied by monitoring apoptosis regulation via the ERKs pathway. Results: SF attenuated DNR-induced cell death (particularly apoptotic death), cTnI and β-tubulin degradation, and cellular morphological changes. SF reduced mitochondrial membrane potential depolarization, cytochrome c leakage, and caspase-9 and caspase-3 activation. SF also decreased ERK1/2, phospho-ERK1/2, p53 and Bax expression and increased Bcl-2 expression. These effects were similar to the results observed when using the pharmacological ERKs phosphorylation inhibitor, AZD6244. Conclusion: We determined that SF protects H9c2 cells from DNR-induced apoptosis through a mechanism that involves the interruption of the ERKs signaling pathway.

(2020) Preventive treatment with ginsenoside Rb1 ameliorates monocrotaline-induced pulmonary arterial hypertension in rats and involves store-operated calcium entry inhibition,

Daunorubicin (DNR) is a widely used chemotherapeutic agent; however, its clinical use is limited because of its cardiotoxicity. This study was aimed to investigate the protective effect of sodium ferulate (SF), an effective component from traditional Chinese herbs, against DNR-induced cardiotoxicity in juvenile rats. DNR was administered intraperitoneally to rats at the dosage of 2.5 mg·kg(-1)·wk(-1) for 5 consecutive weeks (cumulative dose of 12.5 mg/kg) or in combination with intraperitoneal injection of SF at 50 mg·kg(-1)·d(-1) over a period of 30 days. The animals were killed 6 days after the last injection of DNR. SF significantly ameliorated the DNR-induced cardiac dysfunction, structural damage of the myocardium, and release of lactate dehydrogenase and creatine kinase. Treatment with SF also reversed DNR-induced oxidative stress as evidenced by a decrease in malondialdehyde levels with a concomitant increase in myocardical superoxide dismutase activities. Furthermore, SF afforded significant cardioprotection against DNR-induced apoptosis in vivo and effectively suppressed the complex mitochondrion-dependent apoptotic signaling triggered by DNR. This study indicates that SF may improve cardiac function by inhibition of oxidative stress and apoptosis, thus providing a beneficial effect on the prevention of DNR-induced cardiotoxicity.

This study was designed to investigate the effects and mechanisms of ginsenoside Rb1 on pulmonary arteries (PAs) and pulmonary arterial smooth muscle cells (PASMCs) in control and pulmonary hypertension (PH) rats. Isometric tension inPAs, intracellular Ca2+ concentration ([Ca2+]i) and Mn2+ quenching of Fura‐2 in the PASMCs f were measured from control and two widely used models of chronic hypoxia (CH)‐ and monocrotaline (MCT)‐induced PH rats. The results showed that ginsenoside Rb1‐induced dose‐dependent relaxation (0.1‐300 µM, EC50=6 µM ) on PAs precontracted with endothelin‐1 (ET‐1) of control rats. Pretreatment with 6 μM ginsenoside Rb1 attenuated PAs contraction induced by a store‐operated calcium entry (SOCE) activator, 10μM cyclopiazonic acid (CPA) and 10 nM ET‐1 on control, CH‐ and MCT‐treated rats, respectively. 6 μM Ginsenoside Rb1 also induced vasorelaxation of PAs precontracted with 10μM CPA and 10 nM ET‐1 on control, CH‐exposed and MCT‐treated rats, respectively. Moreover, after a SOCE blocker, 20 nM Gd3+ decreased pre contraction induced by 10 nM ET‐1, 6 μM ginsenoside Rb1 can not significantly reduce the PAs contraction again. 6 μM ginsenoside Rb1 significantly decreased 10μM CPA‐induced Ca2+ transients and cation entry by Mn2+ quenching in PASMCs of control, CH‐ and MCT‐ groups. We concluded that ginsenoside Rb1 may take a PAs relaxation via inhibiting SOCE on control, CH‐exposed and MCT‐treated rats. The vasorelaxation of ginsenoside Rb1 in CH‐ and MCT‐induced PH rats may provide a new insight for curing PH.