Qiliqiangxin alleviates Ang II-induced CMECs apoptosis by downregulating autophagy via the ErbB2-AKT-FoxO3a axis.

Our previous work revealed the protective effect of Qiliqiangxin (QLQX) on cardiac microvascular endothelial cells (CMECs), but the underlying mechanisms remain unclear. We aimed to investigate whether QLQX exerts its protective effect against high-concentration angiotensin II (Ang II)-induced CMEC apoptosis through the autophagy machinery. CMECs were cultured in high-concentration Ang II (1 µM) medium in the presence or absence of QLQX for 48 h. We found that QLQX obviously inhibited Ang II-triggered autophagosome synthesis and apoptosis in cultured CMECs. QLQX-mediated protection against Ang II-induced CMEC apoptosis was reversed by the autophagy activator rapamycin. Specifically, deletion of ATG7 in cultured CMECs indicated a detrimental role of autophagy in Ang II-induced CMEC apoptosis. QLQX reversed Ang II-mediated ErbB2 phosphorylation impairment. Furthermore, inhibition of ErbB2 phosphorylation with lapatinib in CMECs revealed that QLQX-induced downregulation of Ang II-activated autophagy and apoptosis was ErbB2 phosphorylation-dependent via the AKT-FoxO3a axis. Activation of ErbB2 phosphorylation by Neuregulin-1ß achieved a similar CMEC-protective effect as QLQX in high-concentration Ang II medium, and this effect was also abolished by autophagy activation. These results show that the CMEC-protective effect of QLQX under high-concentration Ang II conditions could be partly attributable to QLQX-mediated ErbB2 phosphorylation-dependent downregulation of autophagy via the AKT-FoxO3a axis.

Prognostic value of sST2 in patients with heart failure with reduced, mid-range and preserved ejection fraction.

BACKGROUNDS: Prognostic value of soluble suppression of tumorigenecity (sST2), a novel circulating biomarker for myocardial fibrosis, remains elusive in the heart failure patients with preserved ejection fraction (HFpEF). METHODS: 405 consecutive patients with heart failure (HF) were enrolled prospectively, and were grouped into HF with reduced ejection fraction (HFrEF, N = 215), HF with mid-range ejection fraction (HFmrEF, N = 80) and HFpEF (N = 110). The primary endpoint was the composite endpoint of all-cause death and HF rehospitalization. RESULTS: After a median of 12 months, 139 patients reached the primary endpoint, with 57 patients died and 82 patients rehospitalized. Multivariate analysis confirmed that sST2 was an independent risk factor of the primary endpoint for all HF patients [hazard ratio (HR) 2.35, 95% confidence interval (CI) 1.30-4.22, P = 0.004]. Predicting efficacy of sST2 on outcomes was higher for HFpEF (HR 6.48, 95%CI 1.89-22.21, P = 0.003) as compared to HFrEF (HR 3.21, 95% CI 1.67-6.19, P = 0.000). But the association between sST2 and outcomes in HFmrEF is not statistical (HR 3.38, 95%CI 0.82-13.86, P = 0.091). The combined use of sST2 and N terminal pro B type natriuretic peptide (NT-proBNP) could improve the prognostic value compared to using NT-proBNP alone in HFrEF (AUC = 0.794 vs. 0.752, P = 0.034). CONCLUSION: Higher baseline sST2 levels are associated with increased risk of all-cause death and HF rehospitalization in patients with HF independent of ejection fraction. The combined use of sST2 and NT-proBNP could improve the prognostic value than using these two values alone, especially for HFrEF patients.

Diffuse myocardial fibrosis and the prognosis of heart failure with reduced ejection fraction in Chinese patients: a cohort study.

Evidence regarding the relationship between diffuse myocardial fibrosis and the prognosis of heart failure with reduced ejection fraction (HFrEF) was limited. Therefore, this study set out to investigate whether diffuse myocardial fibrosis was independently related to the prognosis of failure with reduced ejection fraction in Chinese patients after adjusting for other covariates. The present study was a cohort study. A total of 45 consecutive HFrEF patients were involved in Zhongshan Hospital of Fudan University in China from 1/9/2015 to 31/12/2016. The target-independent variable was extracellular volume (ECV) quantified by cardiac magnetic resonance T1 mapping using the modified Look-Locker inversion recovery (MOLLI) sequence at baseline. To assess the prognostic impact of MOLLI-ECV, its association with hospitalization for heart failure/cardiac death was tested by multivariable Cox regression analysis. Covariates involved in this study included age, gender, body mass index, heart rate, systolic blood pressure diastolic blood pressure, smoking, hypertension, diabetes mellitus, etiology, NYHA functional class, blood urea nitrogen, creatinine, serum uric acid, total bilirubin, and growth stimulation-expressed gene 2. Ten age- and sex-matched healthy participants with no history of cardiovascular disease served as a control group. Mean MOLLI-ECV was significantly higher in HFrEF patients versus healthy controls (29.55 ± 1.46% vs. 23.17 ± 1.93%, P < 0.001). Patients were followed for 9 months, during which the primary outcome (cardiac death or first heart failure hospitalization) occurred in 15 patients. By Kaplan-Meier analysis, patients with high MOLLI-ECV ≥ 30.10% had shorter event-free survival than the middle (MOLLI-ECV between 30.10 and 28.60) and low (MOLLI-ECV < 28.60) MOLLI-ECV patients (log-rank, P = 0.0035). Result of fully-adjusted multivariable Cox regression analysis showed MOLLI-ECV was positively associated with the composite outcome of HFrEF patients after adjusting confounders hazard ratio (HR) 2.57, 95% CI (1.09, 6.04). By subgroup analysis, a stronger association was seen in patients who with NYHA functional class III-IV, hematocrit < 39.8%, left atrial diameter ≥ 53.5 mm, or without the medical history of MRA or diuretics other than MRA. The P for interaction was < 0.05. In HFrEF patients, the relationship between MOLLI-ECV determined by CMR and the composite outcome is linear. High MOLLI-ECV was associated with a higher rate of cardiac mortality and first HF hospitalization in the short term follow up.

Angiotensin II induces apoptosis of cardiac microvascular endothelial cells via regulating PTP1B/PI3K/Akt pathway.

Endothelial cell apoptosis and renin-angiotensin-aldosterone system (RAAS) activation are the major pathological mechanisms for cardiovascular disease and heart failure; however, the interaction and mechanism between them remain unclear. Investigating the role of PTP1B in angiotensin II (Ang II)-induced apoptosis of primary cardiac microvascular endothelial cells (CMECs) may provide direct evidence of the link between endothelial cell apoptosis and RAAS. Isolated rat CMECs were treated with different concentrations of Ang II to induce apoptosis, and an Ang II concentration of 4 nM was selected as the effective dose for the subsequent studies. The CMECs were cultured for 48 h with or without Ang II (4 nM) in the absence or presence of the PTP1B inhibitor TCS 401 (8 µM) and the PI3K inhibitor LY294002 (10 µM). The level of CMEC apoptosis was assessed by TUNEL staining and caspase-3 activity. The protein expressions of PTP1B, PI3K, Akt, p-Akt, Bcl-2, Bax, caspase-3, and cleaved caspase-3 were determined by Western blot (WB). The results showed that Ang II increased apoptosis of CMECs, upregulated PTP1B expression, and inhibited the PI3K/Akt pathway. Furthermore, cotreatment with PTP1B inhibitor significantly decreased the number of apoptotic CMECs induced by Ang II, along with increased PI3K expression, phosphorylation of Akt and the ratio of Bcl-2/Bax, decreased caspase-3 activity, and a cleaved caspase-3/caspase-3 ratio, while treatment with LY294002 partly inhibited the anti-apoptotic effect of the PTP1B inhibitor. Ang II induces apoptosis of primary rat CMECs via regulating the PTP1B/PI3K/Akt pathway.

Qiliqiangxin attenuates hypoxia-induced injury in primary rat cardiac microvascular endothelial cells via promoting HIF-1α-dependent glycolysis.

Protection of cardiac microvascular endothelial cells (CMECs) against hypoxia injury is an important therapeutic strategy for treating ischaemic cardiovascular disease. In this study, we investigated the effects of qiliqiangxin (QL) on primary rat CMECs exposed to hypoxia and the underlying mechanisms. Rat CMECs were successfully isolated and passaged to the second generation. CMECs that were pre-treated with QL (0.5 mg/mL) and/or HIF-1α siRNA were cultured in a three-gas hypoxic incubator chamber (5% CO2 , 1% O2 , 94% N2 ) for 12 hours. Firstly, we demonstrated that compared with hypoxia group, QL effectively promoted the proliferation while attenuated the apoptosis, improved mitochondrial function and reduced ROS generation in hypoxic CMECs in a HIF-1α-dependent manner. Meanwhile, QL also promoted angiogenesis of CMECs via HIF-1α/VEGF signalling pathway. Moreover, QL improved glucose utilization and metabolism and increased ATP production by up-regulating HIF-1α and a series of glycolysis-relevant enzymes, including glucose transport 1 (GLUT1), hexokinase 2 (HK2), 6-phosphofructokinase 1 (PFK1), pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA). Our findings indicate that QL can protect CMECs against hypoxia injury via promoting glycolysis in a HIF-1α-dependent manner. Lastly, the results suggested that QL-dependent enhancement of HIF-1α protein expression in hypoxic CMECs was associated with the regulation of AMPK/mTOR/HIF-1α pathway, and we speculated that QL also improved HIF-1α stabilization through down-regulating prolyl hydroxylases 3 (PHD3) expression.

Qiliqiangxin protects against anoxic injury in cardiac microvascular endothelial cells via NRG-1/ErbB-PI3K/Akt/mTOR pathway.

Cardiac microvascular endothelial cells (CMECs) are important angiogenic components and are injured rapidly after cardiac ischaemia and anoxia. Cardioprotective effects of Qiliqiangxin (QL), a traditional Chinese medicine, have been displayed recently. This study aims to investigate whether QL could protect CMECs against anoxic injury and to explore related signalling mechanisms. CMECs were successfully cultured from Sprague-Dawley rats and exposed to anoxia for 12 hrs in the absence and presence of QL. Cell migration assay and capillary-like tube formation assay on Matrigel were performed, and cell apoptosis was determined by TUNEL assay and caspase-3 activity. Neuregulin-1 (NRG-1) siRNA and LY294002 were administrated to block NRG-1/ErbB and PI3K/Akt signalling, respectively. As a result, anoxia inhibited cell migration, capillary-like tube formation and angiogenesis, and increased cell apoptosis. QL significantly reversed these anoxia-induced injuries and up-regulated expressions of NRG-1, phospho-ErbB2, phospho-ErbB4, phospho-Akt, phospho-mammalian target of rapamycin (mTOR), hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in CMECs, while NRG-1 knockdown abolished the protective effects of QL with suppressed NRG-1, phospho-ErbB2, phospho-ErbB4, phospho-Akt, phospho-mTOR, HIF-1α and VEGF expressions. Similarly, LY294002 interrupted the beneficial effects of QL with down-regulated phospho-Akt, phospho-mTOR, HIF-1α and VEGF expressions. However, it had no impact on NRG-1/ErbB signalling. Our data indicated that QL could attenuate anoxia-induced injuries in CMECs via NRG-1/ErbB signalling which was most probably dependent on PI3K/Akt/mTOR pathway.