HINT2 protects against pressure overload-induced cardiac remodelling through mitochondrial pathways.

Histidine triad nucleotide-binding protein 2 (HINT2) is an enzyme found in mitochondria that functions as a nucleotide hydrolase and transferase. Prior studies have demonstrated that HINT2 plays a crucial role in ischemic heart disease, but its importance in cardiac remodelling remains unknown. Therefore, the current study intends to determine the role of HINT2 in cardiac remodelling. HINT2 expression levels were found to be lower in failing hearts and hypertrophy cardiomyocytes. The mice that overexpressed HINT2 exhibited reduced myocyte hypertrophy and cardiac dysfunction in response to stress. In contrast, the deficiency of HINT2 in the heart of mice resulted in a worsening hypertrophic phenotype. Further analysis indicated that upregulated genes were predominantly associated with the oxidative phosphorylation and mitochondrial complex I pathways in HINT2-overexpressed mice after aortic banding (AB) treatment. This suggests that HINT2 increases the expression of NADH dehydrogenase (ubiquinone) flavoprotein (NDUF) genes. In cellular studies, rotenone was used to disrupt mitochondrial complex I, and the protective effect of HINT2 overexpression was nullified. Lastly, we predicted that thyroid hormone receptor beta might regulate HINT2 transcriptional activity. To conclusion, the current study showcased that HINT2 alleviates pressure overload-induced cardiac remodelling by influencing the activity and assembly of mitochondrial complex I. Thus, targeting HINT2 could be a novel therapeutic strategy for reducing cardiac remodelling.

Corosolic acid attenuates cardiac fibrosis following myocardial infarction in mice.

Corosolic acid (CRA) is a pentacyclic triterpenoid isolated from Lagerstroemia speciosa. The aim of the present study was to determine whether CRA reduces cardiac remodelling following myocardial infarction (MI) and to elucidate the underlying mechanisms. C57BL/6J mice were randomly divided into control (PBS­treated) or CRA­treated groups. After 14 days of pre­treatment, the mice were subjected to either sham surgery or permanent ligation of the left anterior descending artery. Following surgery, all animals were treated with PBS or CRA (10 or 20 mg/kg/day) for 4 weeks. After 4 weeks, echocardiographic, haemodynamic, gravimetric, histological and biochemical analyses were conducted. The results revealed that, upon MI, mice with CRA treatment exhibited decreased mortality rates, improved ventricular function and attenuated cardiac fibrosis compared with those in control mice. Furthermore, CRA treatment resulted in reduced oxidative stress, inflammation and apoptosis, as well as inhibited the transforming growth factor ß1/Smad signalling pathway activation in cardiac tissue. In vitro studies further indicated that inhibition of AMP­activated protein kinase α (AMPKα) reversed the protective effect of CRA. In conclusion, the study revealed that CRA attenuated MI­induced cardiac fibrosis and dysfunction through modulation of inflammation and oxidative stress associated with AMPKα.

Geniposide protects against sepsis-induced myocardial dysfunction through AMPKα-dependent pathway.

Uncontrolled inflammatory response and subsequent cardiomyocytes loss (apoptosis and pyroptosis) are closely involved in sepsis-induced myocardial dysfunction. Our previous study has found that geniposide (GE) can protect the murine hearts against obesity-induced inflammation. However, the effect of GE on sepsis-related cardiac dysfunction is still unknown. Mice were exposed to lipopolysaccharide (LPS) to generate sepsis-induced myocardial dysfunction. And 50 mg/kg GE was used to treat mice for consecutive 7 days. Our results showed that GE treatment significantly improved survival rate and cardiac function, and suppressed myocardial inflammatory response, as well as myocardial loss in LPS-treated mice. Those effects of GE were largely abolished in NOD-like receptor protein 3 (NLRP3)-deficient mice. Further detection revealed that the inhibition of NLRP3 inflammasome activation depended on the reduction of p47phox by GE. GE treatment restored the phosphorylation and activity of AMP-activated protein kinase α (AMPKα) in the hearts of sepsis mice, and knockout of AMPKα abolished the protection of GE against reactive oxygen species (ROS) accumulation, NLRP3 inflammasome activation and cardiomyocytes loss in sepsis mice. In conclusion, our findings revealed that GE activated AMPKα to suppress myocardial ROS accumulation, thus blocking NLRP3 inflammasome-mediated cardiomyocyte apoptosis and pyroptosis and improving cardiac function in mice with sepsis.

Myricetin Alleviates Pathological Cardiac Hypertrophy via TRAF6/TAK1/MAPK and Nrf2 Signaling Pathway.

Myricetin (Myr) is a common plant-derived polyphenol and is well recognized for its multiple activities including antioxidant, anti-inflammation, anticancer, and antidiabetes. Our previous studies indicated that Myr protected mouse heart from lipopolysaccharide and streptozocin-induced injuries. However, it remained to be unclear whether Myr could prevent mouse heart from pressure overload-induced pathological hypertrophy. Wild type (WT) and cardiac Nrf2 knockdown (Nrf2-KD) mice were subjected to aortic banding (AB) surgery and then administered with Myr (200 mg/kg/d) for 6 weeks. Myr significantly alleviated AB-induced cardiac hypertrophy, fibrosis, and cardiac dysfunction in both WT and Nrf2-KD mice. Myr also inhibited phenylephrine- (PE-) induced neonatal rat cardiomyocyte (NRCM) hypertrophy and hypertrophic markers' expression in vitro. Mechanically, Myr markedly increased Nrf2 activity, decreased NF-κB activity, and inhibited TAK1/p38/JNK1/2 MAPK signaling in WT mouse hearts. We further demonstrated that Myr could inhibit TAK1/p38/JNK1/2 signaling via inhibiting Traf6 ubiquitination and its interaction with TAK1 after Nrf2 knockdown in NRCM. These results strongly suggested that Myr could attenuate pressure overload-induced pathological hypertrophy in vivo and PE-induced NRCM hypertrophy via enhancing Nrf2 activity and inhibiting TAK1/P38/JNK1/2 phosphorylation by regulating Traf6 ubiquitination. Thus, Myr might be a potential strategy for therapy or adjuvant therapy for malignant cardiac hypertrophy.

Corosolic acid ameliorates cardiac hypertrophy via regulating autophagy.

AIM: In this work, we explored the role of corosolic acid (CRA) during pressure overload-induced cardiac hypertrophy. METHODS AND RESULTS: Cardiac hypertrophy was induced in mice by aortic banding. Four weeks post-surgery, CRA-treated mice developed blunted cardiac hypertrophy, fibrosis, and dysfunction, and showed increased LC3 II and p-AMPK expression. In line with the in vivo studies, CRA also inhibited the hypertrophic response induced by PE stimulation accompanying with increased LC3 II and p-AMPK expression. It was also found that CRA blunted cardiomyocyte hypertrophy and promoted autophagy in Angiotensin II (Ang II)-treated H9c2 cells. Moreover, to further verify whether CRA inhibits cardiac hypertrophy by the activation of autophagy, blockade of autophagy was achieved by CQ (an inhibitor of the fusion between autophagosomes and lysosomes) or 3-MA (an inhibitor of autophagosome formation). It was found that autophagy inhibition counteracts the protective effect of CRA on cardiac hypertrophy. Interestingly, AMPK knockdown with AMPKα2 siRNA-counteracted LC3 II expression increase and the hypertrophic response inhibition caused by CRA in PE-treated H9c2 cells. CONCLUSION: These results suggest that CRA may protect against cardiac hypertrophy through regulating AMPK-dependent autophagy.

Protection against Doxorubicin-Induced Cytotoxicity by Geniposide Involves AMPKα Signaling Pathway.

Oxidative stress and cardiomyocyte apoptosis play critical roles in the development of doxorubicin- (DOX-) induced cardiotoxicity. Our previous study found that geniposide (GE) could inhibit cardiac oxidative stress and apoptosis of cardiomyocytes but its role in DOX-induced heart injury remains unknown. Our study is aimed at investigating whether GE could protect against DOX-induced heart injury. The mice were subjected to a single intraperitoneal injection of DOX (15 mg/kg) to induce cardiomyopathy model. To explore the protective effects, GE was orally given for 10 days. The morphological examination and biochemical analysis were used to evaluate the effects of GE. H9C2 cells were used to verify the protective role of GE in vitro. GE treatment alleviated heart dysfunction and attenuated cardiac oxidative stress and cell loss induced by DOX in vivo and in vitro. GE could activate AMP-activated protein kinase α (AMPKα) in vivo and in vitro. Moreover, inhibition of AMPKα could abolish the protective effects of GE against DOX-induced oxidative stress and apoptosis. GE could protect against DOX-induced heart injury via activation of AMPKα. GE has therapeutic potential for the treatment of DOX cardiotoxicity.

The effect of statin treatment on circulating coenzyme Q10 concentrations: an updated meta-analysis of randomized controlled trials.

BACKGROUND: The effect of statin treatment on circulating coenzyme Q10 (CoQ10) has been studied in numerous randomized controlled trails (RCTs). However, whether statin treatment decreases circulating CoQ10 is still controversial. METHODS: PubMed, EMBASE, and the Cochrane Library were searched to identify RCTs to investigate the effect of statin treatment on circulating CoQ10. We calculated the pooled standard mean difference (SMD) using a fixed effect model or random effect model to assess the effect of statin treatment on circulating CoQ10. The methodological quality of the studies was determined according to the Cochrane Handbook. Publication bias was evaluated by a funnel plot, the Egger regression test, and the Begg-Mazumdar correlation test. RESULTS: Twelve RCTs with a total of 1776 participants were evaluated. Compared with placebo, statin treatment resulted in a reduction of circulating CoQ10 (SMD, - 2.12; 95% CI, - 3.40 to - 0.84; p = 0.001), which was not associated with the duration of statin treatment (Exp, 1.00; 95% CI, 0.97 to 1.03; p = 0.994). Subgroup analysis demonstrated that both lipophilic statins (SMD, - 1.91; 95% CI, - 3.62 to 0.2; p = 0.017) and hydrophilic statins (SMD, - 2.36; 95% CI, - 4.30 to - 0.42; p = 0.028) decreased circulating CoQ10, and no obvious difference was observed between the two groups (SMD, - 0.20; 95% CI, - 0.208 to 0.618; p = 0.320). In addition, both low-middle intensity statins (SMD, - 2.403; 95% CI, - 3.992 to - 0.813; p < 0.001) and high intensity statins (SMD, - 1.727; 95% CI, - 2.746 to - 0.709; p < 0.001) decreased circulating CoQ10. Meta-regression showed that the effect of statin on decreasing circulating CoQ10 was not closely associated with the duration of statin treatment (Exp, 1.00; 95% CI, 0.97 to 1.03; p = 0.994). CONCLUSIONS: Statin treatment decreased circulating CoQ10 but was not associated with the statin solution, intensity, or treatment time. The findings of this study provide a potential mechanism for statin-associated muscle symptoms (SAMS) and suggest that CoQ10 supplementation may be a promising complementary approach for SAMS.

Sanguinarine Attenuates Lipopolysaccharide-induced Inflammation and Apoptosis by Inhibiting the TLR4/NF-κB Pathway in H9c2 Cardiomyocytes.

The inflammatory response is involved in the pathogenesis of the most common types of heart disease. Sanguinarine (SAN) has various pharmacological properties such as anti-inflammatory, antioxidant, antibacterial, antitumor, and immune-enhancing properties. However, few studies have investigated the effects of SAN on lipopolysaccharide (LPS)-induced inflammatory and apoptotic responses in H9c2 cardiomyocytes. Therefore, in this study, H9c2 cells were co-treated with SAN and LPS, and the mRNA levels of pro-inflammation markers and the apoptosis rate were measured to clarify the effect of SAN on cardiac inflammation. The underlying mechanism was further investigated by detecting the activation of Toll-like receptor (TLR)4/nuclear factor-κB (NF-κB) signaling pathways. As a result, increased mRNA expression of interleukin (IL)-1ß, IL-6, and TNFα induced by LPS was attenuated after SAN treatment; LPS-induced apoptosis of H9c2 cardiomyocytes and cleaved-caspase 8, 9, 3 were all significantly reduced by SAN. Further experiments showed that the beneficial effect of SAN on blocking the inflammation and apoptosis of H9c2 cardiomyocytes induced by LPS was associated with suppression of the TLR4/NF-κB signaling pathway. It was suggested that SAN suppressed the LPS-induced inflammation and apoptosis of H9c2 cardiomyocytes, which may be mediated by inhibition of the TLR4/NF-κB signaling pathway. Thus, SAN may be a feasible therapy to treat sepsis patients with cardiac dysfunction.

Aucubin Protects against Myocardial Infarction-Induced Cardiac Remodeling via nNOS/NO-Regulated Oxidative Stress.

Whether aucubin could protect myocardial infarction- (MI-) induced cardiac remodeling is not clear. In this study, in a mouse model, cardiac remodeling was induced by left anterior descending coronary artery ligation surgery. Mice were intraperitoneally injected with aucubin (10 mg/kg) 3 days post-MI. Two weeks post-MI, mice in the aucubin treatment group showed decreased mortality, decreased infarct size, and improved cardiac function. Aucubin also decreased cardiac remodeling post-MI. Consistently, aucubin protected cardiomyocytes against hypoxic injury in vitro. Mechanistically, we found that aucubin inhibited the ASK1/JNK signaling. These effects were abolished by the JNK activator. Moreover, we found that the oxidative stress was attenuated in both in vivo aucubin-treated mice heart and in vitro-treated cardiomyocytes, which caused decreased thioredoxin (Trx) consumption, leading to ASK1 forming the inactive complex with Trx. Aucubin increased nNOS-derived NO production in vivo and vitro. The protective effects of aucubin were reversed by the NOS inhibitors L-NAME and L-VINO in vitro. Furthermore, nNOS knockout mice also reversed the protective effects of aucubin on cardiac remodeling. Taken together, aucubin protects against cardiac remodeling post-MI through activation of the nNOS/NO pathway, which subsequently attenuates the ROS production, increases Trx preservation, and leads to inhibition of the ASK1/JNK pathway.

The protective effect of geniposide on human neuroblastoma cells in the presence of formaldehyde.

BACKGROUND: Formaldehyde can induce misfolding and aggregation of Tau protein and ß amyloid protein, which are characteristic pathological features of Alzheimer's disease (AD). An increase in endogenous formaldehyde concentration in the brain is closely related to dementia in aging people. Therefore, the discovery of effective drugs to counteract the adverse impact of formaldehyde on neuronal cells is beneficial for the development of appropriate treatments for age-associated cognitive decline. METHODS: In this study, we assessed the neuroprotective properties of TongLuoJiuNao (TLJN), a traditional Chinese medicine preparation, against formaldehyde stress in human neuroblastoma cells (SH-SY5Y cell line). The effect of TLJN and its main ingredients (geniposide and ginsenoside Rg1) on cell viability, apoptosis, intracellular antioxidant activity and the expression of apoptotic-related genes in the presence of formaldehyde were monitored. RESULTS: Cell counting studies showed that in the presence of TLJN, the viability of formaldehyde-treated SH-SY5Y cells significantly recovered. Laser scanning confocal microscopy revealed that the morphology of formaldehyde-injured cells was rescued by TLJN and geniposide, an effective ingredient of TLJN. Moreover, the inhibitory effect of geniposide on formaldehyde-induced apoptosis was dose-dependent. The activity of intracellular antioxidants (superoxide dismutase and glutathione peroxidase) increased, as did mRNA and protein levels of the antiapoptotic gene Bcl-2 after the addition of geniposide. In contrast, the expression of the apoptotic-related gene - P53, apoptotic executer - caspase 3 and apoptotic initiator - caspase 9 were downregulated after geniposide treatment. CONCLUSIONS: Our results indicate that geniposide can protect SH-SY5Y cells against formaldehyde stress through modulating the expression of Bcl-2, P53, caspase 3 and caspase 9, and by increasing the activity of intracellular superoxide dismutase and glutathione peroxidase.

Inhibitory effect of the paraoxonase gene on the formation of rabbit coronary atherosclerosis.

OBJECTIVE: To observe the effect on the inhibition of coronary atherosclerosis hardening of the paraoxonase gene (PON-1) which transfected to the rabbit epicardial adipose tissue. METHODS: Rabbit coronary atherosclerosis model was established by high-fat feeding, liposome-encapsulated recombinant plasmid pEGFP-PON-1 50 µ L was injected to the rabbit pericardial cavity, and was harvested 4 weeks after transfection. RESULTS: The epicardial fat transfected PON-1 gene had effect on the high lipid level. It significantly increased expression of PON-1 in peripheral arterial vascular tissue (P <0.05); and significantly reduced total cholesterol and low-density lipoprotein cholesterol levels (P<0.05), and the thickness ratio of coronary artery intima/media (P <0.05). CONCLUSIONS: The injection of the PON-1 gene in the pericardial cavity can effectively suppress the formation of coronary atherosclerosis.

Effects of organic solvent and crystal water on γ-chymotrypsin in acetonitrile media: observations from molecular dynamics simulation and DFT calculation.

The use of enzymes in nonaqueous solvent has been one of the most exciting facets of enzymology in recent times; however, the mechanism of how organic solvent and essential water influence on structure and function of enzyme has been not satisfactorily explained in experiments, which limit its further application. Herein, we used molecular dynamics (MD) simulation to study γ-chymotrypsin in two types of media (viz., acetonitrile media with inclusion of 151 crystal water molecules and aqueous solution). On the basis of the MD result, the truncated active site modes containing two specific solvent molecules are furthered studied at the B3LYP/6-31+G(d,p) level of theory within the framework of PCM model. The results show that the acetontrile solvent gives rise to an extent deviation of enzyme structure from the native one, a drop in the flexibility and the total SASA of enzyme. The QM study further reveals that the structure variation of the active pocket caused by acetonitrile would lead to a weakened strength in the catalytic H-bond network, a drop in the pK(a) value of His57, and an increase in the proton transfer barriers from the Ser195 to the His57 residue, which may contribute to the drop in the enzymatic activity in acetontrile media. In addition, the crystal waters play an importance role in retaining the catalytic H-bond network and weakening the acetonitrile-induced variations above, which may be associated with the fact that the enzyme could retain catalytic activity in microhydration acetonitrile media.