Zhilong Huoxue Tongyu capsule improves myocardial ischemia/reperfusion injury via the PI3K/AKT/Nrf2 axis.

INTRODUCTION: Zhilong Huoxue Tongyu Capsule (ZL) is a Chinese medicine used for the treatment of cardio-cerebral diseases. However, the pharmacological mechanisms underlying its regulation of myocardial ischemia/reperfusion injury (MI/RI) remain unclear. PURPOSE: This study aims to investigate the effects and mechanisms of ZL on MI/RI in mice. MATERIALS AND METHODS: C57BL/6J mice were randomly assigned to four groups: Sham group, I/R group, ZL group, and ZLY group. The MI/RI mouse model was established by ligation of the left anterior descending coronary artery for 30 minutes, followed by reperfusion for 120 minutes to restore blood perfusion. Cardiac function was evaluated using cardiac ultrasound. Histopathological changes and myocardial infarction area were assessed using Hematoxylin and eosin (H&E) staining and triphenyltetrazolium chloride (TTC) staining. The changes in oxidative stress- and ferroptosis-related markers were detected. RT-qPCR, Western blot, and ELISA were conducted to further explore the mechanism of ZL in improving MI/RI. RESULTS: Our findings demonstrated that ZL exerted a protective effect against MI/RI by inhibiting ferroptosis, evidenced by the upregulation of antioxidant enzymes such as GSH and GPX4, coupled with the downregulation of ACSL4, a pro-ferroptosis factor. Furthermore, ZL positively impacted the PI3K/AKT/Nrf2 pathway by promoting ATPase activities and enhancing the relative protein expression of its components. Notably, the administration of a PI3K/AKT inhibitor reversed the antioxidant and anti-ferroptosis effects of ZL to some extent, suggesting a potential role for this pathway in mediating ZL's protective effects. CONCLUSIONS: ZL protects against MI/RI-induced ferroptosis by modulating the PI3K/AKT signaling pathway, leading to increased Nrf2 expression and activation of the HO-1/GPX4 pathway. These findings shed light on the potential therapeutic mechanisms of ZL in the context of cardiovascular diseases.

JAK/STAT3 signaling in cardiac fibrosis: a promising therapeutic target.

Cardiac fibrosis is a serious health problem because it is a common pathological change in almost all forms of cardiovascular diseases. Cardiac fibrosis is characterized by the transdifferentiation of cardiac fibroblasts (CFs) into cardiac myofibroblasts and the excessive deposition of extracellular matrix (ECM) components produced by activated myofibroblasts, which leads to fibrotic scar formation and subsequent cardiac dysfunction. However, there are currently few effective therapeutic strategies protecting against fibrogenesis. This lack is largely because the molecular mechanisms of cardiac fibrosis remain unclear despite extensive research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling cascade is an extensively present intracellular signal transduction pathway and can regulate a wide range of biological processes, including cell proliferation, migration, differentiation, apoptosis, and immune response. Various upstream mediators such as cytokines, growth factors and hormones can initiate signal transmission via this pathway and play corresponding regulatory roles. STAT3 is a crucial player of the JAK/STAT pathway and its activation is related to inflammation, malignant tumors and autoimmune illnesses. Recently, the JAK/STAT3 signaling has been in the spotlight for its role in the occurrence and development of cardiac fibrosis and its activation can promote the proliferation and activation of CFs and the production of ECM proteins, thus leading to cardiac fibrosis. In this manuscript, we discuss the structure, transactivation and regulation of the JAK/STAT3 signaling pathway and review recent progress on the role of this pathway in cardiac fibrosis. Moreover, we summarize the current challenges and opportunities of targeting the JAK/STAT3 signaling for the treatment of fibrosis. In summary, the information presented in this article is critical for comprehending the role of the JAK/STAT3 pathway in cardiac fibrosis, and will also contribute to future research aimed at the development of effective anti-fibrotic therapeutic strategies targeting the JAK/STAT3 signaling.

Single-cell RNA sequencing of murine hearts for studying the development of the cardiac conduction system.

The development of the cardiac conduction system (CCS) is essential for correct heart function. However, critical details on the cell types populating the CCS in the mammalian heart during the development remain to be resolved. Using single-cell RNA sequencing, we generated a large dataset of transcriptomes of ~0.5 million individual cells isolated from murine hearts at six successive developmental corresponding to the early, middle and late stages of heart development. The dataset provides a powerful library for studying the development of the heart's CCS and other cardiac components. Our initial analysis identified distinct cell types between 20 to 26 cell types across different stages, of which ten are involved in forming the CCS. Our dataset allows researchers to reuse the datasets for data mining and a wide range of analyses. Collectively, our data add valuable transcriptomic resources for further study of cardiac development, such as gene expression, transcriptional regulation and functional gene activity in developing hearts, particularly the CCS.

[Irisin Alleviates Inflammatory Injury in Diabetic Cardiomyopathy by Regulating NF-κB Pathway].

Objective: To investigate the protective effect of irisin in diabetic cardiomyopathy (DCM) and its mechanism. Methods: A mouse model of DCM was established by high-fat diet combined with the injection of streptozotocin. The mice were assigned to a control group, a DCM group, a DCM+low-dose irisin group, a DCM+high-dose irisin group, and a DCM+pyrrolidine dithiocarbamate (PDTC) (nuclear factor [NF]-κB inhibitor) group. Then, the mice received irisin intervention for 3 weeks after successful modeling. Myocardial morphologic changes were observed by hematoxylin and eosin (HE) staining and Masson staining. The levels of serum creatine kinase (CK) and creatine kinase isoenzyme CK-MB were examined by automatic biochemical analyzer. H9c2 cells were divided into the control group, high glucose and high lipid (HG/HL) group, HG/HL+low-dose irisin group, HG/HL+high-dose irisin group, and HG/HL+PDTC group. CCK-8 assay was conducted to determine cell viability. The expression levels of tumor necrosis factor-α (TNF-α), interleukin (IL)-1ß, and IL-6 in the myocardial tissue and the cells were determined by ELISA. In addition, nuclear translocation of NF-κB p65 protein and the protein expression level of NF-κB inhibitor protein α (IκBα) in the myocardial tissue and the cells were determined by Western blot. Results: According to the results of animal experiment, low and high doses of irisin could alleviate the pathological injury and fibrosis of myocardial tissue to varying degrees. Irisin inhibited the levels of CK, CK-MB, and inflammatory factors, up-regulated IκB protein expression, and diminished NF-κB nuclear translocation. According to the results of cell experiment, low and high doses of irisin could enhance H9c2 cell viability to varying degrees, increase the level of intracellular IκB proteins, and inhibit NF-κB p65 nuclear translocation and inflammatory factor expression. The changes in these aspects in the DCM+low-dose irisin group and the DCM+high-dose irisin group were similar to those in the DCM+PDTC group. Conclusion: Through inhibiting NF-κB p65 nuclear translocation, irisin may reduce the inflammatory response in the myocardial tissue of DCM mice and H9c2 cells of myocardial injury induced by high glucose and high fat, thereby exerting a protective effect on myocardium.

Semaglutide inhibits ischemia/reperfusion-induced cardiomyocyte apoptosis through activating PKG/PKCε/ERK1/2 pathway.

Apoptosis is a major pathophysiological change following myocardial ischemia/reperfusion (I/R) injury. Glucagon-like peptide 1 (GLP-1) and its receptor GLP-1R are widely expressed in the cardiovascular system and GLP-1/GLP-1R activates the protein kinase G (PKG)-related signaling pathway. Therefore, this study tested whether semaglutide, a new GLP-1 analog, inhibits I/R injury-induced cardiomyocyte apoptosis by activating the PKG/PKCε/ERK1/2 pathway. We induced myocardial I/R injury in rats and hypoxia/reoxygenation (H/R) injury in H9C2 cells and detected the effects of semaglutide, a PKG analog (8-Br-cGMP), and a PKG inhibitor (KT-5823) on the PKG/PKCε/ERK1/2 pathway and cardiomyocyte apoptosis. We found that semaglutide upregulated GLP-1R levels, and both semaglutide and 8-Br-cGMP activated the PKG/PKCε/ERK1/2 pathway, inhibited myocardial infarction (MI), decreased hs-cTNT levels, increased NT-proBNP levels, and suppressed cardiomyocyte apoptosis in I/R rats and H/R H9C2 cells. However, KT-5823 exerted contrasting effects with semaglutide and 8-Br-cGMP, and KT-5823 weakened the cardioprotective effects of semaglutide. In conclusion, semaglutide inhibits I/R injury-induced cardiomyocyte apoptosis by activating the PKG/PKCε/ERK1/2 pathway. The beneficial effect of GLP-1/GLP-1R, involved in the activation of the PKG/PKCε/ERK1/2 pathway, may provide a novel treatment method for myocardial I/R injury.

A dataset of dual calcium and voltage optical mapping in healthy and hypertrophied murine hearts.

Pathological hypertrophy underlies sudden cardiac death due to its high incidence of occurrence of ventricular arrhythmias. The alteration of transmural electrophysiological properties in hypertrophic cardiac murine tissue has never been explored previously. In this dataset, we have for the first time conducted high-throughput simultaneous optical imaging of transmembrane potential and calcium transients (CaT) throughout the entire hypertrophic murine hearts at high temporal and spatial resolution. Using ElectroMap, we have conducted multiple parameters analysis including action potential duration/calcium transient duration, conduction velocity, alternans and diastolic interval. Voltage-calcium latency was measured as time difference between action potential and CaT peak. The dataset therefore provides the first high spatial resolution transmural electrophysiological profiling of the murine heart, allowing interrogation of mechanisms driving ventricular arrhythmias associated with pathological hypertrophy. The dataset allows for further reuse and detailed analyses of geometrical, topological and functional analyses and reconstruction of 2-dimensional and 3-dimentional models.

Naringenin: A Promising Therapeutic Agent against Organ Fibrosis.

Fibrosis is the final common pathology of most chronic diseases as seen in the heart, liver, lung, kidney, and skin and contributes to nearly half of death in the developed countries. Fibrosis, or scarring, is mainly characterized by the transdifferentiation of fibroblasts into myofibroblasts and the excessive accumulation of extracellular matrix (ECM) secreted by myofibroblasts. Despite immense efforts made in the field of organ fibrosis over the past decades and considerable understanding of the occurrence and development of fibrosis gained, there is still lack of an effective treatment for fibrotic diseases. Therefore, identifying a new therapeutic strategy against organ fibrosis is an unmet clinical need. Naringenin, a flavonoid that occurs naturally in citrus fruits, has been found to confer a wide range of pharmacological effects including antioxidant, anti-inflammatory, and anticancer benefits and thus potentially exerting preventive and curative effects on numerous diseases. In addition, emerging evidence has revealed that naringenin can prevent the pathogenesis of fibrosis in vivo and in vitro via the regulation of various pathways that involved signaling molecules such as transforming growth factor-ß1/small mother against decapentaplegic protein 3 (TGF-ß1/Smad3), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), sirtuin1 (SIRT1), nuclear factor-kappa B (NF-κB), or reactive oxygen species (ROS). Targeting these profibrotic pathways by naringenin could potentially become a novel therapeutic approach for the management of fibrotic disorders. In this review, we present a comprehensive summary of the antifibrotic roles of naringenin in vivo and in vitro and their underlying mechanisms of action. As a food derived compound, naringenin may serve as a promising drug candidate for the treatment of fibrotic disorders.

miR­541­3p inhibits the viability and migration of vascular smooth muscle cells via targeting STIM1.

The transformation of vascular smooth muscle cells (VSMCs) into the proliferative migratory phenotype in the plaque area contributes to stable plaque formation and facilitates the pathogenesis of atherosclerosis. Stromal interaction molecule 1 (STIM1) has been identified to promote the proliferation of VSMCs, suggesting that STIM1 may be a potent target for the prevention and treatment of atherosclerosis. Bioinformatics analysis has previously predicted STIM1 as a target of microRNA (miR)­541­3p. The present study aimed to determine the effect of the miR­541­3p/STIM1 axis on the progression of atherosclerosis in vitro. Oxidized low­density lipoprotein (ox­LDL)­treated VSMCs were used as an in vitro atherosclerosis model. Cell Counting Kit­8 and Transwell migration assays were used to analyze cell viability and migration, respectively. Reverse transcription­quantitative PCR and western blotting were applied to measure mRNA and protein expression levels, respectively. The association between miR­541­3p and STIM1 was detected using a dual luciferase gene reporter assay. The results of the present study revealed that ox­LDL treatment significantly downregulated miR­541­3p expression levels and upregulated STIM1 expression levels in VSMCs. In addition, ox­LDL stimulation enhanced cell viability and migration. The overexpression of miR­541­3p significantly reversed the ox­LDL­mediated increase in cell viability and migration, whereas the knockdown of miR­541­3p expression enhanced the ox­LDL­mediated effects. STIM1 was confirmed to be a target gene of miR­541­3p in VSMCs. The knockdown of STIM1 significantly impaired the stimulatory effects of miR­541­3p knockdown on cell viability and migration. In conclusion, the findings of the present study suggested that miR­541­3p may efficiently repress VSMC viability and migration by targeting STIM1 under the treatment of ox­LDL. These results indicated that the miR­541­3p/STIM1 axis may represent a potent target to modulate VSMC viability and migration.

Individual Plasmonic Nanoprobes for Biosensing and Bioimaging: Recent Advances and Perspectives.

With the advent of nanofabrication techniques, plasmonic nanoparticles (PNPs) have been widely applied in various research fields ranging from photocatalysis to chemical and bio-sensing. PNPs efficiently convert chemical or physical stimuli in their local environment into optical signals. PNPs also have excellent properties, including good biocompatibility, large surfaces for the attachment of biomolecules, tunable optical properties, strong and stable scattering light, and good conductivity. Thus, single optical biosensors with plasmonic properties enable a broad range of uses of optical imaging techniques in biological sensing and imaging with high spatial and temporal resolution. This work provides a comprehensive overview on the optical properties of single PNPs, the description of five types of commonly used optical imaging techniques, including surface plasmon resonance (SPR) microscopy, surface-enhanced Raman scattering (SERS) technique, differential interference contrast (DIC) microscopy, total internal reflection scattering (TIRS) microscopy, and dark-field microscopy (DFM) technique, with an emphasis on their single plasmonic nanoprobes and mechanisms for applications in biological imaging and sensing, as well as the challenges and future trends of these fields.

P21­activated kinase 1 mediates angiotensin II­induced differentiation of human atrial fibroblasts via the JNK/c­Jun pathway.

Cardiac fibrosis is a common pathophysiological condition involved in numerous types of cardiovascular disease. The renin­angiotensin system, particularly angiotensin II (AngII), serves an important role in cardiac fibrosis and remodeling. Furthermore, p21­activated kinase 1 (PAK1) is a highly conserved serine/threonine protein kinase, which is abundantly expressed in all regions of the heart. However, the role of PAK1 in AngII­mediated activation of cardiac fibroblasts remains unknown. Therefore, the present study aimed to investigate the role of PAK1 in cardiac fibroblasts and its underlying mechanisms. Human cardiac fibroblasts (HCFs) were cultured and treated with PAK1 inhibitor IPA­3 or transduced with PAK1 short hairpin (sh)RNA by lentiviral particles to silence PAK1 expression levels. Subsequently, the cell proliferation and migration abilities of the HCFs were determined. Western blot analysis was used to detect the phosphorylation status of Janus kinase (JNK) and c­Jun. A Cell Counting Kit­8 assay showed that PAK1 inhibition following treatment of HCFs with 5 µM IPA­3 or PAK1­shRNA, significantly attenuated AngII­induced proliferation of fibroblasts. In addition, wound healing and Transwell migration assays demonstrated that inhibition of PAK1 significantly inhibited AngII­induced cell migration. Finally, decreased PAK1 expression levels downregulated AngII­mediated upregulation of α­smooth muscle actin (α­SMA), collagen I, phosphorylated (p)­JNK and p­c­Jun, a downstream molecule of JNK signaling. These findings indicate that PAK1 contributes to AngII­induced proliferation, migration and transdifferentiation of HCFs via the JNK/c­Jun pathway.

Curcumin affects ox-LDL-induced IL-6, TNF-α, MCP-1 secretion and cholesterol efflux in THP-1 cells by suppressing the TLR4/NF-κB/miR33a signaling pathway.

The aim of the present study was to study the molecular mechanism of how curcumin decreases the formation of ox-LDL induced human monocyte macrophage foam cells, promotes the efflux of cholesterol and reduces the secretion of inflammatory cytokines. In vitro cultured THP-1 cells were induced to become macrophages using phorbol-12-myristate-13-acetate. The cells were then pre-treated with curcumin before inducing the foam cell model by addition of oxidized low-density lipoprotein (ox-LDL). Western blot assays were used to detect expression levels of toll-like receptor (TLR)4, nuclear factor κB (NF-κB), NF-κB inhibitor α (IκBα), phosphorylated-IκBα and ATP binding cassette transporter (ABC)A1. Reverse transcription-quantitative PCR was employed to examine mRNA levels of TLR4, microRNA (miR)33a and ABCA1. ELISAs were used to detect inflammatory factors, including tumor necrosis factor (TNF)-α, monocyte chemotactic protein (MCP)-1 and interleukin (IL)-6. ox-LDL successfully induced the foam cell model, promoted phosphorylation of IκBα, promoted nuclear translocation of NF-κB, promoted the expression of TLR4 and miR33a, and promoted the secretion of TNF-α, MCP-1 and Il-6. Additionally, ox-LDL reduced the expression of ABCA1 and cholesterol efflux. However, pretreatment with curcumin increased the expression of ABCA1 and cholesterol efflux and suppressed secretion of TNF-α, MCP-1 and Il-6. TLR4 antibodies, the NF-κB blocker, PDTC, and the miR33a inhibitor also reduced the abnormal transformations induced by ox-LDL. Curcumin promoted cholesterol efflux by suppressing the TLR4/NF-κB/miR33a signaling pathway, and reduced the formation of foam cells and the secretion of inflammatory factors.

Atorvastatin attenuates TGF­ß1­induced fibrogenesis by inhibiting Smad3 and MAPK signaling in human ventricular fibroblasts.

Excessive proliferation and myofibroblasts transformation of cardiac fibroblasts play a critical role in the process of cardiac fibrosis. Atorvastatin (ATV), a 3­hydroxy­3­methyl­glutaryl­coenzyme A reductase inhibitor, is commonly used to treat hypercholesterolemia. It has previously been shown that ATV has potential anti­fibrotic effects. However, the underlying mechanisms of ATV against cardiac fibrosis remain to be fully elucidated, and to the best of our knowledge, there are no reports focusing on the effects of ATV on transforming growth factor­ß1 (TGF­ß1)­induced human ventricular fibroblasts (hVFs) activation. In the present study, hVFs were stimulated with TGF­ß1 with or without pretreatment with ATV. Subsequently, hVF proliferation, cytotoxicity, myofibroblast differentiation and pro­fibrotic gene expression were assessed. Canonical and non­canonical signaling downstream of TGF­ß1, such as Smad3 and mitogen­activated protein kinase (MAPK) signaling, were investigated by evaluating the phosphorylation levels of Smad3, extracellular signal­regulated kinase 1/2, p38 MAPK and c­Jun N­terminal kinase. The results indicated that ATV significantly prevented TGF­ß1­induced cell proliferation, myofibroblast differentiation and production of extracellular matrix proteins, such as matrix metalloproteinase­2, collagen I and collagen III, in hVFs. Furthermore, ATV effectively inhibited TGF­ß1­induced activation of Smad3 and MAPK signaling in hVFs. In conclusion, the present results demonstrated that ATV prevented TGF­ß1­induced fibrogenesis in hVFs, at least in part by inhibiting the Smad3 and MAPK signaling pathways. Therefore, these results imply that ATV may be a promising agent to treat myocardial fibrosis.

Interaction between eNOS gene polymorphism and current smoking on susceptibility to coronary heart disease in Chinese people.

OBJECTIVE: This study aims to explore the relation between endothelial nitric oxide synthase (eNOS) single-nucleotide polymorphisms (SNPs) and the risk of coronary heart disease (CHD). METHODS: SNPstats (online software: http://bioinfo.iconcologia.net/SNPstats) was performed to test Hardy-Weinberg equilibrium in controls. Generalized multifactor dimensionality reduction (GMDR) was adopted to screen the preferable interaction between eNOS SNPs and smoking. RESULTS: The frequency for the rs1799983-T allele was 31.1% in CHD patients, which was significantly higher than that of 19.8% in controls (P < 0.05). The frequency for the rs891512-A allele was 28.8% in cases, which was also significantly higher than that of 20.1% in controls (P < 0.05). Logistic regression analysis showed that both rs1799983-T and rs891512-A alleles were related with increased risk of CHD, and the odds ratios (ORs) [95% confidence interval (CI)] were 1.71 (1.31-2.15) and 1.57 (1.14-2.07), respectively. High-order interactions were investigated among SNPs and environmental factors using the GMDR method. The data showed that a two-locus model (rs1799983 × smoking) had a testing accuracy of 0.60 (P = 0.001). We found that current smokers with rs1799983-GT or TT within eNOS gene have the highest CHD risk, compared to never smokers with rs1799983-GG genotype, OR (95% CI) = 2.74 (1.78-3.85), after covariates adjustment for age, gender, BMI, and alcohol drinking. CONCLUSION: The rs1799983-T and rs891512-A alleles and interaction between rs1799983 and smoking were all risk factors of CHD.

MiR-26b Suppresses the Development of Stanford Type A Aortic Dissection by Regulating HMGA2 and TGF-ß/Smad3 Signaling Pathway.

PURPOSE: Stanford type A aortic dissection (TAAD) is one of the most dangerous cardiovascular diseases. MicroRNAs (miRNAs) have been considered as potential therapeutic targets for TAAD. In this present study, we aimed to investigate the functional role and regulatory mechanism of miR-26b in TAAD development. MATERIALS AND METHODS: MiR-26b mRNA expression was detected by real-time polymerase chain reaction (RT-PCR) and protein levels were measured by Western blot. Verifying the direct target of miR-26b was used by dual luciferase assay, RT-PCR, and Western blot. Cell Counting Kit-8 (CCK-8) and TUNEL staining assays were applied for detecting rat aortic vascular smooth muscle cells (VSMCs) viability and apoptosis, respectively. RESULTS: We found that miR-26b was under-expressed in TAAD patients and closely associated with the poor prognosis of TAAD patients. Re-expression of miR-26b facilitated while knockdown of miR-26b inhibited VSMC proliferation. However, miR-26b showed the opposite effect on cell apoptosis. More importantly, high-mobility group AT-hook 2 (HMGA2) was verified as the direct target of miR-26b. Furthermore, transforming growth factor beta (TGF-ß)/Smad3 signaling pathway was involved in the development of TAAD modulated by miR-26b. CONCLUSION: miR-26b impeded TAAD development by regulating HMGA2 and TGF-ß/Smad3 signaling pathway, which provided a potential biomarker for TAAD treatment.

Mitochondrial tRNASer(UCN) 7471delC may be a novel mutation associated with maternally transmitted hypertension.

OBJECTIVE: The objective of the study was to investigate the association between mitochondrial DNA (mtDNA) mutations and essential hypertension (EH). METHODS: One Han Chinese pedigree with maternally inherited EH was recruited in the current study. The matrilineal relatives from this family underwent clinical, genetic, and molecular analysis. Moreover, the mtDNA gene mutations were screened by PCR and direct Sanger sequence. Evolutionary conservation was performed and the secondary structure of mt-tRNASer(UCN) with and without the 7471delC was evaluated by the RNA Fold Webserver program. Moreover, the pathogenicity scoring system was used to assess the 7471delC. RESULTS: This Chinese pedigree exhibited a relative high penetrance and expressivity of EH. Of 13 matrilineal relatives, 5 of them suffered from high blood pressure (BP). Genetic analysis of the complete mtDNA genes showed the presence of a novel tRNASer(UCN) 7471delC, together with a set of polymorphisms belonging to the human mitochondrial haplogroup G2a1. In fact, the 7471delC occurred within the T-stem and extra arm of tRNASer(UCN), which was very conserved from bacteria to human mitochondria. Interestingly, the 7472insC which was located at the same position had been regarded as a pathogenic mutation associated with non-syndromic hearing loss. In addition, bioinformatics analysis revealed that the 7471delC affected the secondary structure of tRNASer(UCN). The pathogenicity scoring system showed that the 7471delC may be "possibly pathogenic" associated with EH. CONCLUSION: We believed that the 7471delC may impair the mitochondrial functional and played an active role in the pathogenesis of EH in this pedigree. The 7471delC may be a novel risk factor for maternally transmitted EH.

Activation of TGR5 Partially Alleviates High Glucose-Induced Cardiomyocyte Injury by Inhibition of Inflammatory Responses and Oxidative Stress.

High glucose- (HG-) induced cardiomyocyte injury is the leading cause of diabetic cardiomyopathy, which is associated with the induction of inflammatory responses and oxidative stress. TGR5 plays an important role in the regulation of glucose metabolism. However, whether TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury is unknown. Neonatal mouse cardiomyocytes were isolated and incubated in a HG medium. Protein and mRNA expression was detected by western blotting and RT-PCR, respectively. Cell apoptosis was determined by Hoechst 33342 staining and flow cytometry. After treatment of cells with HG, TGR5-selective agonist INT-777 reduced the increase in expression of proinflammatory cytokines and NF-κB, whereas pretreatment of cells with TGR5 shRNA significantly reduced the inhibitory effects of INT-777. We also found that INT-777 increased the protein expression of Nrf2 and HO-1. In the presence of TGR5 shRNA, the expression of Nrf2 and HO-1 was reduced, indicating that TGR5 may exert an antioxidant effect partially through the Nrf2/HO-1 pathway. Furthermore, INT-777 treatment inhibited HG-induced ROS production and apoptosis that were attenuated in the presence of TGR5 shRNA or ZnPP (HO-1 inhibitor). Activation of TGR5 has cardioprotective effects against HG-induced cardiomyocyte injury and could be a pharmacological target for the treatment of diabetic cardiomyopathy.

Advanced Glycation End Products: Potential Mechanism and Therapeutic Target in Cardiovascular Complications under Diabetes.

The occurrence and development of cardiovascular complications are predominantly responsible for the increased morbidity and mortality observed in patients with diabetes. Oxidative stress under hyperglycemia is currently considered the initial link to diabetic cardiovascular complications and a key node for the prevention and treatment of diabetes-related fatal cardiovascular events. Numerous studies have indicated that the common upstream pathway in the context of oxidative stress in the cardiovascular system under diabetic conditions is the interaction of advanced glycation end products (AGEs) with their receptors (RAGEs). Therefore, a further understanding of the relationship between oxidative stress and AGEs is of great significance for the prevention and treatment of cardiovascular complications in patients with diabetes. In this review, we will briefly summarize the recent research advances in diabetes with an emphasis on oxidative stress and its association with AGEs in diabetic cardiovascular complications.

Hyperpolarization-Activated Cyclic Nucleotide-Gated Ion (HCN) Channels Regulate PC12 Cell Differentiation Toward Sympathetic Neuron.

Hyperpolarization-activated cyclic nucleotide-gated ion channels (HCN channels) are widely expressed in the central and peripheral nervous systems and organs, while their functions are not well elucidated especially in the sympathetic nerve. The present study aimed to investigate the roles of HCN channel isoforms in the differentiation of sympathetic neurons using PC12 cell as a model. PC12 cells derived from rat pheochromocytoma were cultured and induced by nerve growth factor (NGF) (25 ng/ml) to differentiate to sympathetic neuron-like cells. Sympathetic directional differentiation of PC12 cells were evaluated by expressions of growth-associated protein 43 (GAP-43) (a growth cone marker), tyrosine hydroxylase (TH) (a sympathetic neuron marker) and neurite outgrowth. Results show that the HCN channel isoforms (HCN1-4) were all expressed in PC12 cells; blocking HCN channels with ivabradine suppressed NGF-induced GAP-43 expression and neurite outgrowth; silencing the expression of HCN2 and HCN4 using silenced using small interfering RNAs (siRNA), rather than HCN1 and HCN3, restrained GAP-43 expression and neurite outgrowth, while overexpression of HCN2 and HCN4 channels with gene transfer promoted GAP-43 expression and neurite outgrowth. Patch clamp experiments show that PC12 cells exhibited resting potentials (RP) of about -65 to -70 mV, and also presented inward HCN channel currents and outward (K+) currents, but no inward voltage-gated Na+ current was induced; NGF did not significantly affect the RP but promoted the establishment of excitability as indicated by the increased ability to depolarize and repolarize in the evoked suspicious action potentials (AP). We conclude that HCN2 and HCN4 channel isoforms, but not HCN1 and HCN3, promote the differentiation of PC12 cells toward sympathetic neurons. NGF potentiates the establishment of excitability during PC12 cell differentiation.

Association Between γ-Glutamyltransferase Level and Cardiovascular or All-Cause Mortality in Patients With Coronary Artery Disease: A Systematic Review and Meta-Analysis.

This meta-analysis assessed the prognostic value of serum γ-glutamyltransferase (GGT) level for cardiovascular (CV) and all-cause mortality in patients with coronary artery disease (CAD). We conducted a systematic literature search of PubMed, Web of Science, Embase, China National Knowledge Infrastructure, Wanfang, and Weipu databases until December 2018. Observational studies investigating the prognostic role of serum GGT level for CV and all-cause mortality in patients with CAD were included. Pooled risk ratios (RR) with 95% confidence intervals (CI) for the highest versus the lowest GGT level were used to summarize the prognostic value. Twelve studies involving 12 531 patients with CAD were included. Meta-analysis showed that elevated GGT level was significantly associated with higher risk of CV mortality (RR: 2.04; 95% CI: 1.57-2.64) and all-cause mortality (RR: 1.49; 95% CI: 1.27-1.74) in patients with CAD. This meta-analysis suggests that elevated serum GGT levels are an independent predictor of CV and all-cause mortality in patients with CAD. Determination of GGT level may improve the prediction of CV and all-cause mortality in patients with CAD.

Curcumin increases cholesterol efflux via heme oxygenase­1­mediated ABCA1 and SR­BI expression in macrophages.

Curcumin, which is an extract from a traditional Chinese medicine, has previously been demonstrated to exhibit an anti­atherosclerotic effect, which is closely associated with an increase in cholesterol efflux. However, it is unclear as to whether the increased effect is mediated by heme oxygenase (HO)­1. Macrophages were treated with different concentrations of curcumin, HO­1 inhibitor and small interfering (si)RNA in different experiments. Analysis of protein expression was conducted via western blotting. mRNA expression levels were measured using reverse transcription­polymerase chain reaction. Antioxidant response element (ARE)­driven promoter activity was measured by a dual­luciferase reporter assay. The cholesterol efflux analysis was performed by fluorescence­labelled cholesterol (NBD) using a multi­label counter. In the present study, the results indicated that curcumin increased the cholesterol efflux from macrophages. Additionally, curcumin significantly upregulated HO­1 expression. The HO­1 inhibitor (zinc protoporphyrin) partly blocked this effect. Curcumin also promoted scavenger receptor class B type I (SR­BI) and ATP­binding cassette transporter A1 (ABCA1) expression. HO­1 small interfering (si)RNA partly abolished the increased SR­BI and ABCA1 expression induced by curcumin. Furthermore, the nuclear factor, erythroid 2 like 2 (Nrf2) expression in the nucleus was dose­dependently increased by curcumin. Nrf2 siRNA successfully inhibited the curcumin­induced HO­1 expression. Curcumin significantly increased Nrf2­driven luciferase activity. Overall, these data indicated that curcumin activates the Nrf2­ARE signaling pathway and upregulates HO­1 expression, which mediates SR­BI and ABCA1 expression and thereby increases cholesterol efflux.