Elevated circulating inflammatory biomarker levels in the SIRT1-NF-κB-sCD40L pathway in patients with acute myocardial infarction: a case-control study.

BACKGROUND: Inflammation plays a key role in atherosclerosis development and progression. However, the role of novel inflammatory biomarker pathways, namely the SIRT1-NF-κB-sCD40L, in the etiopathogenesis of human atherosclerosis remains undefined. This study was designed to evaluate the changes and clinical implications of these inflammatory mediators in the plasma of patients with acute myocardial infarction (AMI). METHODS: The peripheral arterial blood of 88 participants (68 patients with AMI and 20 age-matched controls), was drawn prior to performing coronary angiography (CAG). The SIRT1, NF-κB, and sCD40L plasma levels were quantified using ELISA. Spearman's analysis was used to evaluate the correlation between the three inflammatory markers, while Pearson's test assessed their potential correlation with cardiac troponin T (TNT) levels. Sensitivity, specificity, and area under the ROC curve (AUC) were calculated as measures of diagnostic accuracy. RESULTS: Patients with AMI showed higher levels of circulating SIRT1, NF-κB, and sCD40L compared to the age-matched controls (p < 0.05). However, the plasma concentrations of these three inflammatory mediators did not differ between the ST-segment elevation myocardial infarction (STEMI) and non-STEMI (NSTEMI) patients. Additionally, in patients with AMI, the SIRT1 level was positively correlated with NF-κB and sCD40L levels (p < 0.001). Likewise, the levels of SIRT1, NF-κB and sCD40L were positively correlated with TNT levels (p < 0.001). More importantly, the ROC analysis showed that the diagnostic accuracy of AMI was significantly higher when NF-κB or sCD40L level was used in combination with TNT levels (p < 0.05). CONCLUSIONS: The levels of the circulating inflammatory biomarkers, including SIRT1, NF-κB, and sCD40L, were significantly elevated in patients with AMI. These novel biomarkers can improve the diagnostic accuracy of AMI when combined with TNT.KEY MESSAGESAMI is a potentially lethal CAD and is the leading cause of mortality and morbidity worldwide. Inflammation plays a key role in atherosclerosis development and progression. The levels of the circulating novel inflammatory biomarkers, including SIRT1, NF-κB, and sCD40L, were significantly elevated in patients with AMI.The SIRT1 level was positively correlated with NF-κB and sCD40L levels in patients with AMI.The levels of SIRT1, NF-κB and sCD40L were positively correlated with TNT levels.The ROC analysis showed that the diagnostic accuracy of AMI was significantly higher when NF-κB or sCD40L level was used in combination with TNT levels.SIRT1/NF-κB/sCD40L axis inhibition is a potential new target for AMI treatment.

Activation of p62-NRF2 Axis Protects against Doxorubicin-Induced Ferroptosis in Cardiomyocytes: A Novel Role and Molecular Mechanism of Resveratrol.

Doxorubicin (DOX) is a most common anthracycline chemotherapeutic agent; however, its clinical efficacy is limited due to its severe and irreversible cardiotoxicity. Ferroptosis, characterized by iron overload and lipid peroxidation, plays a pivotal role in DOX-induced cardiotoxicity. Resveratrol (RSV) displays cardioprotective and anticancer effects, owing to its antioxidative and anti-inflammatory properties. However, the role and mechanism of RSV in DOX-mediated ferroptosis in cardiomyocytes is unclear. This study showed that DOX decreased cell viability, increased iron accumulation and lipid peroxidation in H9c2 cells; however, these effects were reversed by RSV and ferroptosis inhibitor ferrostatin-1 (Fer-1) pre-treatment. Additionally, RSV significantly increased the cell viability of H9c2 cells treated with ferroptosis inducers Erastin (Era) and RSL3. Mechanistically, RSV inhibited mitochondrial reactive oxygen species (mtROS) overproduction and upregulated the p62-NRF2/HO-1 pathway. RSV-induced NRF2 activation was partially dependent on p62, and the selective inhibition of p62 (using p62-siRNA interference) or NRF2 (using NRF2 specific inhibitor, ML385) significantly abolished the anti-ferroptosis function of RSV. Furthermore, RSV treatment protected mice against DOX-induced cardiotoxicity, including significantly improving left ventricular function, ameliorating myocardial fibrosis and suppressing ferroptosis. Consistent with in vitro results, RSV also upregulated the p62-NRF2/HO-1 expression, which was inhibited by DOX, in the myocardium. Notably, the protective effect of RSV in DOX-mediated ferroptosis was similar to that of Fer-1 in vitro and in vivo. Thus, the p62-NRF2 axis plays a critical role in regulating DOX-induced ferroptosis in cardiomyocytes. RSV as a potent p62 activator has potential as a therapeutic target in preventing DOX-induced cardiotoxicity via ferroptosis modulation.

Silencing TXNIP ameliorates high uric acid-induced insulin resistance via the IRS2/AKT and Nrf2/HO-1 pathways in macrophages.

Insulin resistance (IR) promotes atherosclerosis and increases the risk of diabetes and cardiovascular diseases. Our previous studies have demonstrated that high uric acid (HUA) increased oxidative stress, leading to IR in cardiomyocytes and pancreatic ß cells. However, whether HUA can induce IR in monocytes/macrophages, which play critical roles in all stages of atherosclerosis, is unclear. Recent findings revealed that thioredoxin-interacting protein (TXNIP) negatively regulates insulin signaling; however, the roles and mechanisms of TXNIP in HUA-induced IR remain unclear. Therefore, in this study, we investigated the function of TXNIP in macrophages treated with UA. Transcriptomic profiling revealed TXNIP as one of the most upregulated genes, and subsequent RT-PCR and Western blot analyses confirmed that TXNIP was upregulated by HUA. HUA treatment significantly increased mitochondrial reactive oxygen species (MtROS) levels and decreased insulin-stimulated glucose uptake. Silencing TXNIP by RNA interference significantly diminished HUA-induced oxidative stress and IR. Mechanistically, silencing TXNIP reversed the inhibition of the phosphorylation of insulin receptor substrate 2 (IRS2)/protein kinase B (AKT) pathway induced by HUA. Additional study revealed that HUA induced the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling pathway, but silencing TXNIP abolished it. Moreover, Nrf2 inhibitor (ML385) ameliorated HUA-induced IR independent of IRS2/AKT signaling. Probenecid, a well-known UA-lowering drug, significantly suppressed the activation of TXNIP and Nrf2/HO-1 signaling. Furthermore, RNA-seq revealed that activation of the TXNIP-related redox pathway may be a key regulator in patients with asymptomatic hyperuricemia. These data suggest that silencing TXNIP could ameliorate HUA-induced IR via the IRS2/AKT and Nrf2/HO-1 pathways in macrophages. Additionally, TXNIP might be a promising therapeutic target for preventing and treating oxidative stress and IR induced by HUA.

Whole-exome sequencing reveals MYH7 p.R671C mutation in three different phenotypes of familial hypertrophic cardiomyopathy.

Familial hypertrophic cardiomyopathy (HCM) is one of the most common types of genetic heart disorder and features high genetic heterogeneity. HCM is a major cause of sudden cardiac death and also an important cause of heart failure-related disability. A pedigree with suspected familial HCM was recruited for the present study to identify genetic abnormalities. HCM was confirmed by echocardiography and clinical data of the family members were collected. Genomic DNA was extracted from the peripheral blood and sequenced based on standard whole-exome sequencing (WES) protocols. Sanger sequencing was further performed to verify mutation sites and their association with HCM. WES and Sanger sequencing revealed a heterozygous missense mutation (c.2011C>T p.R671C) in myosin heavy chain 7 (MYH7) that was identified in three family members. The Arg671Cys mutation was located in exon 18 and, to the best of our knowledge, has not been previously reported in familial HCM. Furthermore, family members carrying the same mutated gene were of different sexes and clinical phenotypes. They included the proband, a 17-year-old survivor of sudden cardiac arrest with ventricular systolic dysfunction, the proband's maternal uncle, who presented with ventricular diastolic dysfunction and the proband's mother, who had no obvious clinical symptoms and did not present with cardiac dysfunction. However, echocardiology indicated that the proband's mother had an enlarged left atrium, slightly thicker right anterior wall and anterior septum and an expanded atrial septum. Therefore, HCM exhibited obvious genetic and phenotypic heterogeneity. To the best of our knowledge, the present study was the first to report such a mutation in the MYH7 gene in familial HCM. In addition, the present study demonstrated that WES is a powerful tool for identifying genetic variants in HCM.

The role and molecular mechanism of FoxO1 in mediating cardiac hypertrophy.

Cardiac hypertrophy can lead to heart failure and cardiovascular events and has become a research hotspot in the field of cardiovascular disease. Despite extensive and in-depth research, the pathogenesis of cardiac hypertrophy is far from being fully understood. Increasing evidence has shown that the transcription factor forkhead box protein O 1 (FoxO1) is closely related to the occurrence and development of cardiac hypertrophy. This review summarizes the current literature on the role and molecular mechanism of FoxO1 in cardiac hypertrophy. We searched the database MEDLINE via PubMed for available evidence on the effect of FoxO1 on cardiac hypertrophy. FoxO1 has many effects on multiple diseases, including cardiovascular diseases, diabetes, cancer, aging, and stem cell activity. Recent studies have shown that FoxO1 plays a critical role in the development of cardiac hypertrophy. Evidence for this relationship includes the following. (i) FoxO1 can regulate cardiac growth/protein synthesis, calcium homeostasis, cell apoptosis, and autophagy and (ii) is controlled by several upstream signalling molecules (e.g. phosphatidylinositol 3-kinase/Akt, AMP-activated protein kinase, and sirtuins) and regulates many downstream transcription proteins (e.g. ubiquitin ligases muscle RING finger 1/muscle atrophy F-box, calcineurin/nuclear factor of activated T cells, and microRNAs). In response to stress or external stimulation (e.g. low energy, oxidative stress, or growth factor signalling), FoxO1 undergoes post-translational modification and transfers from the cytoplasm to nucleus, thus regulating the expression of a series of target genes in myocardium that are involved in cardiac growth/protein synthesis, calcium homeostasis, cell apoptosis, and autophagy. (iii) Finally, targeted regulation of FoxO1 is an effective method of intervening in myocardial hypertrophy. The information reviewed here should be significant for understanding the roles of FoxO1 in cardiac hypertrophy and should contribute to the design of further studies related to FoxO1 and the hypertrophic response. It should also shed light on a potential treatment for cardiac hypertrophy.

Structural characterisation and ACE-inhibitory activities of polysaccharide from Gastrodia elata Blume.

The structural properties and Angiotensin-I converting enzyme (ACE) inhibition activities of a polysaccharide (PGE) extracted from Gastrodia elata Blume were investigated. PGE was extracted using hot water and purified by Sephadex G-200 followed by ultra-filtration. The structural characterisation of PGE was analysed by FT-IR, NMR spectroscopy, specific rotation determination, periodate oxidation-smith degradation, methylation analysis, GC-MS and Congo red test. The results revealed that PGE was composed by glucose, with an average molecular weight of 1.54 × 103 kDa. The structure of PGE was 1→3 and 1→4,6-branched-glucopyranose that had a linear backbone of (1 → 4)-linked-d-glucopyranose (Glcp). ACE-inhibitory activity results showed that PGE was efficient to inhibit ACE and the IC50 value was 0.66 mg/mL.

Moderate calorie restriction attenuates age­associated alterations and improves cardiac function by increasing SIRT1 and SIRT3 expression.

Calorie restriction (CR) extends the lifespan of mammals and improves cardiac function by attenuation of age­associated alterations. Sirtuins (SIRT) are involved in these mechanisms, however, the extent to which CR affects cardiac function and sirtuin expression remains unknown. Therefore, the present study aimed to determine to what extent CR affects cardiac function and sirtuin expression. A total of 60 female Sprague­Dawley rats were randomly divided into four groups, including normal control (NC), 25% calorie restriction (25% CR), 45% calorie restriction (45% CR) and high­fat diet (HF). The groups were maintained on these specific regimens for 2 months. CR rats were observed to have significantly lower body weight, heart weight, and left ventricle mass index compared with NC and HF rats. Visceral fat, triglyceride, and low density lipoprotein levels were significantly decreased in CR rats. Compared with the 25% CR group, the 45% CR group heart function decreased. The heart rate, left ventricular systolic pressure, +dp/dt and ­dp/dt of the 45% CR rats decreased, whereas the left ventricular end­diastolic pressure increased. To explore the molecular mechanism of CR on cardiac function, immunoblotting was used to detect the protein expression of SIRT1 and SIRT3. The 25% CR diet increased the expression of SIRT1 and SIRT3 in myocardium, whereas the 45% CR and HF diets resulted in a decrease in SIRT1 and SIRT3 expression. Moderate calorie restriction (25% CR) improves cardiac function by attenuation of age­associated alterations in rats. SIRT1 and SIRT3 are associated with these effects.

SIRT3 protects cardiomyocytes from oxidative stress-mediated cell death by activating NF-κB.

Oxidative stress-mediated cell death in cardiomyocytes reportedly plays an important role in many cardiac pathologies. Our previous report demonstrated that mitochondrial SIRT3 plays an essential role in mediating cell survival in cardiac myocytes, and that resveratrol protects cardiomyocytes from oxidative stress-induced apoptosis by activating SIRT3. However, the exact mechanism by which SIRT3 prevents oxidative stress remains unknown. Here, we show that exposure of H9c2 cells to 50 µM H(2)O(2) for 6h caused a significant increase in cell death and the down-regulation of SIRT3. Reactive oxygen species (ROS)-mediated NF-κB activation was involved in this SIRT3 down-regulation. The SIRT3 activator, resveratrol, which is considered an important antioxidant, protected against H(2)O(2)-induced cell death, whereas the SIRT inhibitor, nicotinamide, enhanced cell death. Moreover, resveratrol negatively regulated H(2)O(2)-induced NF-κB activation, whereas nicotinamide enhanced H(2)O(2)-induced NF-κB activation. We also found that SOD2, Bcl-2 and Bax, the downstream genes of NF-κB, were involved in this pathological process. These results suggest that SIRT3 protects cardiomyocytes exposed to oxidative stress from apoptosis via a mechanism that may involve the NF-κB pathway.

Red wine may be used in the therapy of myocarditis.

Myocarditis is one of the most commonly cardiovascular diseases in clinical practice, but the treatment is always limited at present. Considering the multifactorial etiology of myocarditis, a novel therapeutic agent with multi-bioactivties should be presented. Red wine has been recognized as a favorable natural medicine against a large number of pathologic conditions. Recent results indicate that red wine could effectively decrease inflammatory factors secretion, reduce the migration of neutrophils, antagonize oxidation, and regulate immunity. By these bioactivities of anti-inflammation, anti-oxidation, and immunomodulation, red wine may be an effective therapeutic candidate to manage the symptoms and prevent the recurrence of myocarditis.

Insulin signaling: a possible pathogenesis of cardiac hypertrophy.

Cardiac hypertrophy is one of the most commonly cardiovascular diseases in clinical practice. Despite the extensive studies, the pathophysiology of cardiac hypertrophy, however, remains incompletely understood. Studies have demonstrated that insulin signaling may be involved in cardiac growth and protein synthesis. More recently, a growing body of evidence suggests that insulin signaling is associated with the development of cardiac hypertrophy. The evidence for the hypotheses included that (1) several studies have demonstrated insulin is an important regulator of physiological cardiac growth; (2) PI3K-Akt pathway has been investigated as a participant in the cardiac hypertrophic program; (3) negative regulators of insulin signaling show beneficial effects on cardiac hypertrophy development; and (4) insulin signaling interaction with angiotensin II in cardiac hypertrophy. Although the studies suggest that the association between insulin signaling and cardiac hypertrophy, the exact pathogenesis of insulin signaling in cardiac hypertrophy development remains elusive and requires further investigation. Insulin signaling may provide a scientific basis for further research on the underlying mechanisms of cardiac hypertrophy and may target for pharmacological interruption of cardiac hypertrophy.

SIRT1: a novel target to prevent atherosclerosis.

Atherosclerosis is a chronic immuno-inflammatory disease associated with blood lipids disorder. Many studies have demonstrated that caloric restriction (CR) can prevent atherosclerosis and extend lifespan. Sir2 protein, mammal's SIRT1, has been reported to at least partly contribute to the protective effect of CR. Hence, we hypothesize that SIRT1 is a key regulator in the pathogenesis of atherosclerosis and that upregulation of SIRT1 in endothelial cells may mimic CR's beneficial effect on vascular health. The recent studies have demonstrated that endothelial SIRT1 is an anti-atherosclerosis factor and the possible mechanism may be related to inhibit oxidized low-density lipoprotein (oxLDL)-induced apoptosis, upregulate endothelial nitric oxide synthase (eNOS) expression, and improve endothelium relaxation function. We infer that SIRT1 may be a novel target for atherosclerosis prevention and treatment.

Effects of resveratrol on H(2)O(2)-induced apoptosis and expression of SIRTs in H9c2 cells.

Resveratrol, a polyphenol found in fruits, has been demonstrated to activate Sir2. Though many studies have demonstrated that resveratrol can activate SIRT1, whether it has effect on other sirtuins (SIRT2-7) are unknown. The present study shows that exposure of H9c2 cells to 50 microM H(2)O(2) for 6 h caused a significant increase in apoptosis, as evaluated by TUNEL and flow cytometry (FCM), but pretreatment of resveratrol (20 microM) eliminated H(2)O(2)-induced apoptosis. Resveratrol also prevented H(2)O(2)-induced caspase-3 activation. Exposure of cells to resveratrol caused rapid activation of SIRT1,3,4,7. Sirtuin inhibitor, nicotinamide (20 mM) attenuated resveratrol's inhibitory effect on cell apoptosis and caspase-3 activity. These results suggest that resveratrol protects cardiomyocytes from H(2)O(2)-induced apoptosis by activating SIRT1,3,4,7.

Resveratrol protects cardiomyocytes from hypoxia-induced apoptosis through the SIRT1-FoxO1 pathway.

Loss of cardiomyocytes through apoptosis has been proposed as a cause of ventricular remodeling and heart failure. Ischemia- and hypoxia-induced apoptosis of cardiomyocytes reportedly plays an important role in many cardiac pathologies. We investigated whether resveratrol (Res) has direct cytoprotective effects against ischemia/hypoxia for cardiomyocytes. Exposure of H9c2 embryonic rat heart-derived cells to hypoxia for 24h caused a significant increase in apoptosis, as evaluated by TUNEL and flow cytometry, while treatment with 20 microM Res greatly decreased hypoxia-induced apoptosis in these cells. Exposure of the cells to Res (20 microM) caused rapid activation of SIRT1, which had a dual effect on FoxO1 function: SIRT1 increased FoxO1's ability to induce cell cycle arrest, but inhibited FoxO1's ability to induce cell death. This effect could be reversed by SIRT1 inhibition. Results of our study indicate that Res inhibits hypoxia-induced apoptosis via the SIRT1-FoxO1 pathway in H9c2 cells. This polyphenol may have potential in preventing cardiovascular disease, especially in coronary artery disease (CAD) patients.