Naoxintong/PPARα Signaling Inhibits H9c2 Cell Apoptosis and Autophagy in Response to Oxidative Stress

Naoxintong capsule for treating cardiovascular and cerebrovascular diseases: from bench to bedside

Naoxintong Capsule (NXT), a renowned traditional Chinese medicine (TCM) formulation, has been broadly applied in China for more than 30 years. Over decades, accumulating evidences have proven satisfactory efficacy and safety of NXT in treating cardiovascular and cerebrovascular diseases (CCVD). Studies have been conducted unceasingly, while this growing latest knowledge of NXT has not yet been interpreted properly and summarized comprehensively. Hence, we systematically review the advancements in NXT research, from its chemical constituents, quality control, pharmacokinetics, to its profound pharmacological activities as well as its clinical applications in CCVD. Moreover, we further propose specific challenges for its future perspectives: 1) to precisely clarify bioactivities of single compound in complicated mixtures; 2) to evaluate the pharmacokinetic behaviors of NXT feature components in clinical studies, especially drug-drug interactions in CCVD patients; 3) to explore and validate its multi-target mechanisms by integrating multi-omics technologies; 4) to re-evaluate the safety and efficacy of NXT by carrying out large-scale, multicenter randomized controlled trials. In brief, this review aims to straighten out a paradigm for TCM modernization, which help to contribute NXT as a piece of Chinese Wisdom into the advanced intervention strategy for CCVD therapy.

An Energy Metabolism Study on the Efficacy of Naoxintong Capsules against Myocardial Infarction in a Rat Model

Background

In myocardial ischemia, optimizing the myocardial metabolic phenotype to improve cardiac function is critical. Naoxintong capsules (NXT) are widely prescribed in Chinese medicine for the treatment of cerebrovascular and cardiovascular diseases.

Methods

In this study, a rat model of myocardial infarction was established by ligation of the left anterior descending coronary artery. The structure and function of the heart were evaluated using echocardiography. The pathological changes of the rat myocardium and the myocardial volume collagen fraction (CVF) were examined using hematoxylin-eosin (HE) and Masson's trichrome staining (Masson). The expression of TNF-α and IL-6 were detected by immunohistochemistry. The level of cTnT was also measured to evaluate myocardial injury. In order to study the changes in energy metabolism in myocardial infarction and the effects of NXT, a targeted analysis method for detecting the 29 energy metabolites in cardiac muscle tissue was developed based on UPLC-QQQ-MS. Western blotting was used to detect the expression of proteins related to energy metabolism in myocardia.

Results

In the rat model of myocardial infarction, NXT showed obvious effects, such as improving heart function and increasing LVEF and LVFS. HE staining, Masson staining, and immunohistochemical results revealed that NXT decreased inflammatory infiltration, improved myocardial fibrosis, and reduced infarct size. In addition, NXT significantly reduced the level of serum cTnT. The levels of the 29 energy metabolites in cardiac muscle tissue were analyzed using a newly developed targeted analysis method. Compared to the sham group, the levels of 17 metabolites from different energy metabolic pathways, including four compounds in glycolysis metabolism, four compounds in TCA cycle, three compounds in oxidative phosphorylation, four compounds in purine metabolism, and two compounds in glutathione metabolism, displayed obvious changes induced by myocardial ischemia. Expressions of SIRT1, PGC-1α, and ATP5D proteins related to energy metabolism were decreased after myocardial infarction. These perturbations could all be reversed by NXT intervention, suggesting that the therapeutic effects of NXT were partially due to interferences with energy metabolisms.

Conclusion

This study provides a useful approach for investigating the mechanism of myocardial infarction and evaluating the efficacy of NXT from energy metabolism.

Qili Qiangxin, a compound herbal medicine formula, alleviates hypoxia-reoxygenation-induced apoptotic and autophagic cell death via suppression of ROS/AMPK/mTOR pathway in vitro

OBJECTIVE

Qili Qiangxin (QLQX), a compound herbal medicine formula, is used effectively to treat congestive heart failure in China. However, the molecular mechanisms of the cardioprotective effect are still unclear. This study explores the cardioprotective effect and mechanism of QLQX using the hypoxia-reoxygenation (H/R)-induced myocardial injury model.

METHODS

The main chemical constituents of QLQX were analyzed using high-performance liquid chromatography-evaporative light-scattering detection. The model of H/R-induced myocardial injury in H9c2 cells was developed to simulate myocardial ischemia-reperfusion injury. Apoptosis, autophagy, and generation of reactive oxygen species (ROS) were measured to assess the protective effect of QLQX. Proteins related to autophagy, apoptosis and signalling pathways were detected using Western blotting.

RESULTS

Apoptosis, autophagy and the excessive production of ROS induced by H/R were significantly reduced after treating the H9c2 cells with QLQX. QLQX treatment at concentrations of 50 and 250 μg/mL caused significant reduction in the levels of LC3II and p62 degradation (P < 0.05), and also suppressed the AMPK/mTOR signalling pathway. Furthermore, the AMPK inhibitor Compound C (at 0.5 μmol/L), and QLQX (250 μg/mL) significantly inhibited H/R-induced autophagy and apoptosis (P < 0.01), while AICAR (an AMPK activator, at 0.5 mmol/L) increased cardiomyocyte apoptosis and autophagy and abolished the anti-apoptotic effect of QLQX. Similar phenomena were also observed on the expressions of apoptotic and autophagic proteins, demonstrating that QLQX reduced the apoptosis and autophagy in the H/R-induced injury model via inhibiting the AMPK/mTOR pathway. Moreover, ROS scavenger, N-Acetyl-L-cysteine (NAC, at 2.5 mmol/L), significantly reduced H/R-triggered cell apoptosis and autophagy (P < 0.01). Meanwhile, NAC treatment down-regulated the ratio of phosphorylation of AMPK/AMPK (P < 0.01), which showed a similar effect to QLQX.

CONCLUSION

QLQX plays a cardioprotective role by alleviating apoptotic and autophagic cell death through inhibition of the ROS/AMPK/mTOR signalling pathway.

Evaluation of the anti-inflammatory and antioxidant pharmcodynamic compoents of naoxintong capsules as a basis of broad spectrum effects

CONTEXT

Naoxintong capsule (NXT) is one of the most prevalent Traditional Chinese Medicine formulations in the treatment of coronary heart disease (CHD), yet the action of pharmacodynamic components remains unclear.

OBJECTIVE

To determine the basis by which pharmacodynamic components of NXT may be effective in the treatment of CHD.

MATERIALS AND METHODS

The protective effect of NXT (0.01-100 μg/mL) on 293 T and hy926 cells was determined by MTT assay for 24 h. Afterwards, to investigate the pharmacodynamic material basis of NXT in anti-inflammatory and antioxidant effects, based on previous UPLC/Q-TOF analysis, 293 T and hy926 cells were divided into control (treated with solvent), model (incubated with TNF-α, LPS or H₂O₂), intervention (treated with UPLC components) and positive groups. After 24 h of treatment, all cells were tested to verify the screening results. MOE software was applied to dock bioactive compounds with phosphoinositide 3-kinase (PI3K), then the protein expression and phosphate levels were determined by western blotting.

RESULTS

NXT could significantly inhibit the expression of NF-κB, MMP-9 and NO in cells with IC₅₀ values of 0.1178, 0.1182 and 0.1094 μg/mL. Based on the screening results, six components of NXT were identified (calycosin, ferulic acid, salvianolic acid B, ononin, salvianolic acid E, and salvianolic acid F) which can inhibit NF-κB, MMP-9, and NO simultaneously, while exerting cytoprotective effects by inhibiting the activation of the PI3K/AKT pathway under different conditions by virtue of their advantageous interaction with PI3K.

CONCLUSIONS

These ingredients have outstanding therapeutic potential and may provide a scientific basis for the future application and research of NXT.

Myocardial protective effect and transcriptome profiling of Naoxintong on cardiomyopathy in zebrafish

Background

Cardiomyopathy is a kind of cardiovascular diseases, which makes it more difficult for the heart to pump blood to other parts of the body, eventually leading to heart failure. Naoxintong (NXT), as a traditional Chinese Medicine (TCM) preparation, is widely used in the treatment of cardiovascular diseases, including cardiomyopathy, while its underlying mechanism has not been fully elucidated. The purpose of this study is to investigate the therapeutic effect of NXT on cardiomyopathy and its molecular mechanism in zebrafish model.

Methods

The zebrafish cardiomyopathy model was established using terfenadine (TFD) and treated with NXT. The therapeutic effect of NXT on cardiomyopathy was evaluated by measuring the heart rate, the distance between the sinus venosus and bulbus arteriosus (SV-BA), the pericardial area, and the blood flow velocity of zebrafish. Then, the zebrafish hearts were isolated and collected; transcriptome analysis of NXT on cardiomyopathy was investigated. Moreover, the heg1 mutant of zebrafish congenital cardiomyopathy model was used to further validate the therapeutic effect of NXT on cardiomyopathy. Additionally, UPLC analysis combined with the zebrafish model investigation was performed to identify the bioactive components of NXT.

Results

In the TFD-induced zebrafish cardiomyopathy model, NXT treatment could significantly restore the cardiovascular malformations caused by cardiac dysfunction. Transcriptome and bioinformatics analyses of the TFD and TFD  +  NXT treated zebrafish developing hearts revealed that the differentially expressed genes were highly enriched in biological processes such as cardiac muscle contraction and heart development. As a cardiac development protein associated with cardiomyopathy, HEG1 had been identified as one of the important targets of NXT in the treatment of cardiomyopathy. The cardiovascular abnormalities of zebrafish heg1 mutant could be recovered significantly from NXT treatment, including the expanded atrial cavity and blood stagnation. qRT-PCR analysis further showed that NXT could restore cardiomyopathy phenotype in zebrafish through HEG1-CCM signaling. Among the seven components identified in NXT, paeoniflorin (PF) and salvianolic acid B (Sal B) were considered to be the main bioactive ones with myocardial protection.

Conclusion

NXT presented myocardial protective effect and could restore myocardial injury and cardiac dysfunction in zebrafish; the action mechanism was involved in HEG1-CCM signaling.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00532-0.

Naoxintong Retards Atherosclerosis by Inhibiting Foam Cell Formation Through Activating Pparα Pathway

BACKGROUNDS

We recently reported that Naoxintong (NXT), a China Food and Drug Administration (FDA)-approved cardiac medicine, could reduce the plaque size, but the underlying mechanism remains elusive now.

OBJECTIVE

In this study, we investigated the effects of NXT on foam cell accumulation both in vivo and in vitro and explored related mechanisms.

METHOD

THP-1 cells and bone marrow-derived macrophages were incubated with oxidized low-density lipoprotein (ox-LDL) with/without Naoxintong. ApoE-/- mice fed an atherogenic diet were administered to receive NXT for eight weeks. Macrophage-derived foam cell formation in plaques was measured by immunohistochemical staining. Expression of proteins was evaluated by Western blot. Lentivirus was used to knockdown PPARα in THP-1 cells.

RESULTS

After NXT treatment, foam cell accumulation was significantly reduced in atherosclerotic plaques. Further investigation revealed that oxidized low-density lipoprotein (ox-LDL) uptake was significantly decreased and expression of scavenger receptor class A (SR-A) and class B (SR-B and CD36) was significantly downregulated post-NXT treatment. On the other hand, NXT increased cholesterol efflux and upregulated ATP-binding cassette (ABC) transporters (ABCA-1 and ABCG-1) in macrophages. Above beneficial effects of NXT were partly abolished after lentiviral knockdown of PPARα.

CONCLUSION

Our findings suggest that NXT could retard atherosclerosis by inhibiting foam cell formation through reducing ox-LDL uptake and enhancing cholesterol efflux and above beneficial effects are partly mediated through PPARα pathway.

Naoxintong inhibits myocardial infarction injury by VEGF/eNOS signaling-mediated neovascularization

ETHNOPHARMACOLOGICAL RELEVANCE

Naoxintong capsules (NXT), a traditional Chinese Medical preparation, are widely used for treatment of cardiovascular diseases, while the mechanism is still unclear.

MATERIALS AND METHODS

Myocardial infarction (MI) was induced by ligation of the left coronary artery in mice. Echocardiographic measurements were performed to do physiological assessments of left ventricle (LV) function. Histological and immunohistochemical staining was used to determine infarct size, capillary density, tissue endothelial nitric oxide synthase (eNOS) expression. Bone Marrow Transplantation (BMT) model and flow cytometric (FCM) analyses were applied to assay endothelial progenitor cells (EPCs) mobilization. Quantitative Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR), Western blotting and enzyme-linked immunosorbent assay (ELISA) were performed to detect the expressions of vascular endothelial growth factor (VEGF), kinase domain region (KDR), phosphorylated-Akt (p-Akt), phosphorylated-eNOS (p-eNOS).

RESULTS

NXT administration reduced myocardium fibrosis and increased myocardium capillary density in response to MI. NXT increased circulating Sca1⁺/ Fetal liver kinase 1 (Flk1)⁺ mononuclear cells (MNCs) and soluble Kit ligand (sKitL) of bone marrow (BM) in response to MI. In mice transplanted with green fluorescent protein (GFP) BM cells, NXT increased the numbers of GFP-positive cells at the border zone of the ischemic region in MI-induced mice. NXT increased the numbers of eNOS-expressing BM-derived cells in tissues, which was involved in increased the expressions of VEGF, KDR, p-eNOS, p-Akt in the myocardium.

CONCLUSION

NXT-mediated recovery in MI-induced mice was involved in mobilization and incorporation of bone marrow-derived EPCs/circulating angiogenic cells (CACs) leading to enhancement of neovascularization via VEGF/eNOS signaling.

Naoxintong/PPAR Signaling Inhibits Cardiac Hypertrophy via Activation of Autophagy

As a traditional Chinese medicine, Naoxintong capsule (NXT) has been approved by China Food and Drug Administration (CFDA), which is used for cardiocerebrovascular disease treatment. Here we found that NXT extract significantly promoted H9c2 cardiomyocyte cell autophagy involved in increased autophagy-associated gene expression leading to inhibition of mTOR signaling. Moreover, NXT extract increased PPARγ protein expression and transcription activity of H9c2 cell. Consistent with this, in PPARγ gene silenced H9c2 cells, NXT had no effect on autophagy and mTOR signaling. Furthermore, NXT/PPARγ-mediated H9c2 autophagy led to inhibition of cardiomyocyte cell hypertrophy. These findings suggest that the extract of NXT inhibited H9c2 cardiomyocyte cell hypertrophy via PPARγ-mediated cell autophagy.