GP73 enhances the ox-LDL-induced inflammatory response in THP-1 derived macrophages via affecting NLRP3 inflammasome signaling.

BACKGROUND: Atherosclerosis is a chronic inflammatory disease with its molecular basis incompletely understood. Here, we determined whether the Golgi phosphoprotein 73 (GP73), a novel protein highly related to inflammation and disrupted lipid metabolism, was involved in the development of atherosclerosis. METHODS: Public microarray databases of human vascular samples were analyzed for expression patterns. Apolipoprotein-E-gene-deficient (ApoE-/-) mice (8-week-old) were randomly assigned to either a chow diet group or a high-fat diet group. The levels of serum GP73, lipid profiles and key inflammatory cytokines were determined by ELISA. The aortic root plaque was isolated and used for by Oil Red O staining. PMA-differentiated THP-1 macrophages were transfected with GP73 small interfering RNA (siRNA) or infected with adenovirus expressing GP73, and then stimulated with oxidized low density lipoprotein (ox-LDL). The expressions of pro-inflammatory cytokines and signal pathway key targets were determined by ELISA kit and Western blot respectively. In addition, ichloro-dihydro-fluorescein diacetate (DCFH-DA) was used to measure the intracellular ROS levels. RESULTS: The expressions of GP73 and NLRP3 were substantially upregulated in human atherosclerotic lesions. There were significant linear correlations between GP73 and inflammatory cytokines expressions. High-fat diet-induced atherosclerosis and increased levels of plasma inflammatory mediators (IL-1ß, IL-18, and TNF-α) were observed in ApoE-/- mice. Besides, the expressions of GP73 in the aorta and serum were significantly upregulated and positively correlated with the NLRP3 expression. In the THP-1 derived macrophages, ox-LDL treatment upregulated the expressions of GP73 and NLRP3 proteins and activated the inflammatory responses in a concentration-dependent and time-dependent manner. Silencing of GP73 attenuated the inflammatory response and rescued the decreased migration induced by ox-LDL, inhibiting the NLRP3 inflammasome signaling and the ROS and p-NF-κB activation. CONCLUSIONS: We demonstrated that GP73 promoted the ox-LDL-induced inflammation in macrophages by affecting the NF-κB/NLRP3 inflammasome signaling, and may play a role in atherosclerosis.

D-galactose-induced cardiac ageing: A review of model establishment and potential interventions.

Cardiovascular disease (CVD) is highly prevalent in an ageing society. The increased incidence and mortality rates of CVD are global issues endangering human health. There is an urgent requirement for understanding the aetiology and pathogenesis of CVD and developing possible interventions for preventing CVD in ageing hearts. It is necessary to select appropriate models and treatment methods. The D-galactose-induced cardiac ageing model possesses the advantages of low mortality, short time and low cost and has been increasingly used in the study of cardiovascular diseases in recent years. Therefore, understanding the latest progress in D-galactose-induced cardiac ageing is valuable. This review highlights the recent progress and potential therapeutic interventions used in D-galactose-induced cardiac ageing in recent years by providing a comprehensive summary of D-galactose-induced cardiac ageing in vivo and in vitro. This review may serve as reference literature for future research on age-related heart diseases.

Deep Phenotyping and Prediction of Long-term Cardiovascular Disease: Optimized by Machine Learning.

BACKGROUND: Prediction of cardiovascular disease (CVD) is important in clinical practice. Machine learning (ML) may offer an improved alternative to current CVD risk stratification in individual patients. We aim to identify important predictors and compare ML models with traditional models according to their prediction performance in a large long-term follow-up cohort. METHODS: The Atherosclerosis Risk in Communities (ARIC) study was designed to study the progression of subclinical disease to cardiovascular events over a 25-year follow-up period. All phenotypic variables at visit 1 were obtained. All-cause death, CVD, and coronary heart disease were the outcomes for analysis. The ML framework involved variable selection using the random survival forest (RSF) method, model building, and 5-fold cross-validation. Model performance was evaluated by discrimination using the Harrell concordance index (C-index), accuracy using the Brier score (BS), and interpretability using the number of variables in the model. RESULTS: Of the 14,842 participants in ARIC, the average age was 54.2 years, with 45.2% male and 26.2% Black participants. Thirty-eight unique variables were selected in the RSF top 20 importance ranking of all 6 outcomes. Aging, hypertension, glucose metabolism, renal function, coagulation, adiposity, and sodium retention dominated the predictions of all outcomes. The ML models outperformed the regression models and established risk scores with a higher C-index, lower BS, and varied interpretability. CONCLUSIONS: The ML framework is useful for identifying important predictors of CVD and for developing models with robust performance compared with existing risk models.

NLRP3 inflammasome activation contributes to the pathogenesis of cardiocytes aging.

OBJECTIVE: The NOD-like receptor protein 3 (NOD-like receptor protein 3, NLRP3) inflammasome is associated with many physiological processes related to aging. We investigated whether NLRP3 inflammasome activation contributes to the pathogenesis of cardiocytes aging dissected the underlying mechanism. METHODS: H9c2 cells were treated with different concentrations of D-galactose (D-gal, 0, 2, 10 and 50 g/L) for 24 hours. The cytochemical staining, flow cytometry and fluorescence microscope analysis were employed to detect the ß-galactosidase (ß-gal) activity. Western blot analysis was used to detect the age-associated proteins (P53, P21) and NLRP3 inflammasome proteins [NLRP3, apoptosis-associated speck-like protein (ASC)]. Confocal fluorescent images were applied to capture the colocalization of NLRP3 and caspase-1. Intracellular reactive oxygen species (ROS) was measured using 2'7'-dichlorodihydrofluorescein diacetate (DCFH-DA) by flow cytometry and visualized using a fluorescence microscope. The IL-1ß, IL-18 and lactate dehydrogenase (LDH) release were also detected. RESULTS: D-gal induced-H9c2 cells caused cardiocytes' aging changes (ß-gal staining, CellEvent™ Senescence Green staining, P53, P21) in a concentration-dependent manner. NLRP3 inflammasomes were activated, IL-1ß, IL-18 and LDH release and ROS generation were increased in the cardiocytes aging progress. When MCC950 inhibited NLRP3 inflammasomes, it attenuated the cardiocytes aging, yet the ROS generation was similar. Inhibition of ROS by NAC attenuated cardiocytes aging and inhibited the NLRP3 inflammasome activation at the same time. NLRP3 inflammasome activation by nigericin-induced cardiocytes cells aging progress. CONCLUSIONS: NLRP3 inflammasome activation contributes to the pathogenesis of cardiocytes aging, and ROS generation may serve as a potential mechanism by which NLRP3 inflammasome is activated.

Hypertension and Atrial Fibrillation: A Study on Epidemiology and Mendelian Randomization Causality.

Introduction: Hypertension (HT) and atrial fibrillation (AF) often coexist. However, the causality between these two conditions remains to be determined. Methods: We used individual participant data from the Atherosclerosis Risk in Communities (ARIC) prospective cohort with 9,474 participants. HT was ascertained at visit 1 (1987-1989), and incident AF was identified by ECGs conducted during study examinations at each visit, hospital discharge codes, and death certificates. We used the Kaplan-Meier estimate to compute the cumulative incidence of AF by the HT subgroup. Then we used Cox hazard regression model to assess the association between HT and incident AF. The causality between genetically determined HT and AF was analyzed by the two-sample Mendelian randomization (MR) based on publicly summarized genome-wide association studies (GWASs) data. Results: A total of 1,414 cases (14.9%) of AF were identified during the follow-up period (median 24.1 years). After adjusting for all covariates, the hazard ratio between the participants with HT and incident AF was 1.50 [95% confidence interval (CI) 1.29-1.73]. In the HT → AF MR analysis, we detected a causal correlation between HT and AF (OR: 1.90, 95% CI 1.18-3.04, P = 0.01) with no evidence of heterogeneity from single-nucleotide polymorphisms. Besides, the genetically determined SBP and DBP (10 mmHg) were consistently associated with a higher risk of AF. Conclusions: In the ARIC study, the incident AF increased by 50% in patients with HT. In the MR analysis, our results supported causal inference between HT and AF.

Causal effect of education on type 2 diabetes: A network Mendelian randomization study.

BACKGROUND: The causality between education and type 2 diabetes (T2DM) remains unclear. AIM: To identify the causality between education and T2DM and the potential metabolic risk factors [coronary heart disease (CHD), total cholesterol, low-density lipoprotein, triglycerides (TG), body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting insulin, fasting glucose, and glycated hemoglobin] from summarized genome-wide association study (GWAS) data used a network Mendelian randomization (MR). METHODS: Two-sample MR and network MR were performed to obtain the causality between education-T2DM, education-mediator, and mediator-T2DM. Summary statistics from the Social Science Genetic Association Consortium (discovery data) and Neale Lab consortium (replication data) were used for education and DIAGRAMplusMetabochip for T2DM. RESULTS: The odds ratio for T2DM was 0.392 (95%CI: 0.263-0.583) per standard deviation increase (3.6 years) in education by the inverse variance weighted method, without heterogeneity or horizontal pleiotropy. Education was genetically associated with CHD, TG, BMI, WC, and WHR in the discovery phase, yet only the results for CHD, BMI, and WC were replicated in the replication data. Moreover, BMI was genetically associated with T2DM. CONCLUSION: Short education was found to be associated with an increased T2DM risk. BMI might serve as a potential mediator between them.

Education and heart failure: New insights from the atherosclerosis risk in communities study and mendelian randomization study.

INTRODUCTION: We aim to characterize the nature and magnitude of the prospective association between education and incident heart failure (HF) in the Atherosclerosis Risk in Communities (ARIC) Study and investigate any causal relevance to the association between them. METHODS: The final sample size was 12,315 in this study. Baseline characteristics between education levels were compared using 1-way ANOVA test, the Kruskal-Wallis test, or the χ2 test. We used the Kaplan-Meier estimate to compute the cumulative incident of HF by education levels and the difference in estimate was compared using the log-rank test. Cox hazard regression models were used to explore the association between education levels and incident HF. Two-sample Mendelian randomization (MR) based on publicly available summary-level data from genome-wide association studies (GWASs) was used to estimate the causal influence of the education and incident HF. RESULTS: During a median follow-up of 25.1years, 2453 cases (19.9%) of incident HF occurred. After multiple adjustments in the final model, participants in the intermediate and advanced education levels were still associated with 18% and 21% decreased rate of incident HF separately. In MR analysis, we detected a protective causal association between education and HF (P=0.005). CONCLUSIONS: Participants with higher education levels were associated with a decreased rate of incident HF. There was a causal association between education and HF.

Causal assessment of sleep on coronary heart disease.

OBJECTIVE: Sleep is an essential physiological process that protects our physical and mental health. However, the causality of the association between sleep and coronary heart disease (CHD) is unknown. Mendelian randomization (MR), using genetic variants as instrumental variables to test for causality, can infer credible causal associations. We applied a two-sample MR framework to determine the causal association between sleep (sleeplessness, sleep duration, and daytime dozing) and CHD by integrating summary-level genome-wide association study (GWAS) data. METHODS: Data included in this study were the GWAS summary statistics datasets from the C4D Consortium for CHD; Neale Lab UKB-a:13 Consortium for sleeplessness; Neale Lab UKB-a:9 Consortium for sleep duration and Neale Lab UKB-a:15 Consortium for daytime dozing. The conventional MR approach (inverse variance weighted, IVW) method and Egger method were used. Heterogeneity was calculated using each of the different MR methods where possible. Horizontal pleiotropy was evaluated by p-value of the MR-Egger intercept. RESULTS: The IVW method estimate indicated that the odds ratio (OR) (95% confidence interval, CI) for CHD was 3.924 (1.345-11.447) per standard deviation increase in sleeplessness (p = 0.012). Results were consistent in MR-Egger method (OR, 4.654; 95% CI, 1.191-18.186; p = 0.009). The genetically predicted sleeplessness was positively casually associated with CHD. The causal association between sleep duration (or daytime dozing) and CHD was not established. CONCLUSION: Our analysis provided evidence supporting a causal relationship between sleeplessness (not sleep duration or daytime dozing) and CHD.

Serum albumin and atrial fibrillation: insights from epidemiological and mendelian randomization studies.

Atrial fibrillation (AF) is the most common arrhythmia in clinical practice. Low serum albumin level is linked to the emergence of many cardiovascular diseases, including AF. In this study, we aim to characterize the nature and magnitude of the prospective association between serum albumin and incident AF in the Atherosclerosis Risk in Communities (ARIC) Study and investigate any causal relevance to the association between them. ARIC Study is a population-based, prospective, cohort study of cardiovascular risk factors in four US communities, initially consisting of 15,792 participants, aged 45-64 years, recruited between 1987 and 1989 (visit 1). The final sample size was 12,833 in this study. Baseline (visit 1) characteristics were compared between groups using one-way ANOVA test, Chi square test, or Kruskal-Wallis test as appropriate. We used multivariable Cox' hazard regression models to assess the association between albumin and incident AF. Two-sample Mendelian randomization (MR) based on publicly available summary-level data from genome-wide association studies was used to estimate the causal influence of the serum albumin and incident AF. During a median follow-up of 25.1 years, 2259 (17.6%) participants developed incident AF. After multiple adjustment, serum albumin was inversely associated with incidence of AF [HR = 0.90, 95% CI 0.86-0.94, per SD (0.27 g/dL) increase; HR = 0.80, 95% CI 0.71-0.91, Q4 vs. Q1]. In MR analysis, we detected no evidence for a causal relation between serum albumin level and AF in inverse-variance weighted (IVW) method (odds ratio: 0.996, 95% CI 0.980-1.012, per 1 g/dL increase of albumin; P = 0.620) without evidence of heterogeneity between estimates from individual SNPs (Pheterogeneity = 0.981 [MR-Egger] and Pheterogeneity = 0.860 [IVW]) nor pleiotropy effect (Ppleiotropy = 0.193). The serum albumin level is independently inverse associated with incident AF in a linear pattern. However, MR analyses did not support a causal role of serum albumin in the etiology of AF.

Exploring the causal pathway from omega-6 levels to coronary heart disease: A network Mendelian randomization study.

BACKGROUND AND AIMS: Evidence on the effect of omega-6 fats on coronary heart disease (CHD) risk remains inconclusive. We applied a network MR framework to determine the causal effects between omega-6 levels and CHD and the potential cholesterol metabolic risk factors (Total cholesterol, TC; Low-density lipoprotein cholesterol, LDL-C; High-density lipoprotein cholesterol, HDL-C; Triglycerides, TG) which might act as mediators in the link between omega-6 levels and CHD by integrating summary-level genome wide association study (GWAS) data. METHODS AND RESULTS: Network MR analysis-an approach using genetic variants as the instrumental variables for both the exposure and mediator to infer causality was performed to examine the causal effects between omega-6 levels and CHD and cholesterol metabolic risk factors. Summary statistics from the Kettunen et al. 's consortium were used (n = 13506) for omega-6, CARDIoGRAMplusC4D consortium data were used (n = 184305) for CHD, and GLGC consortia data were used (n = 108363) for TC, LDL-C, HDL-C, and TG. The IVW method estimate indicated that the odds ratio (OR) (95% confidence interval [CI]) for CHD was 1.210 (1.118-1.310) per standard deviation increase in omega-6. Results were consistent in MR Egger method (OR, 1.418; 95% CI, 1.087-1.851; P = 0.050) and weighted median methods (OR, 1.239; 95% CI, 1.125-1.364; P = 0.000). Omega-6 was positively causal associated with TC, LDL-C, and TG but was not associated with HDL-C. Moreover, TC, LDL-C, and TG were positively associated with CHD. CONCLUSIONS: Using a network MR framework, we provided evidence supporting a positive causal relationship between omega-6 and CHD, which might be partially mediated by TC, LDL-C, and TG.

Phenomapping of subgroups in hypertensive patients using unsupervised data-driven cluster analysis: An exploratory study of the SPRINT trial.

BACKGROUND: Hypertensive patients are highly heterogeneous in cardiovascular prognosis and treatment responses. A better classification system with phenomapping of clinical features would be of greater value to identify patients at higher risk of developing cardiovascular outcomes and direct individual decision-making for antihypertensive treatment. METHODS: An unsupervised, data-driven cluster analysis was performed for all baseline variables related to cardiovascular outcomes and treatment responses in subjects from the Systolic Blood Pressure Intervention Trial (SPRINT), in order to identify distinct subgroups with maximal within-group similarities and between-group differences. Cox regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for cardiovascular outcomes and compare the effect of intensive antihypertensive treatment in different clusters. RESULTS: Four replicable clusters of patients were identified: cluster 1 (index hypertensives); cluster 2 (chronic kidney disease hypertensives); cluster 3 (obese hypertensives) and cluster 4 (extra risky hypertensives). In terms of prognosis, individuals in cluster 4 had the highest risk of developing primary outcomes. In terms of treatment responses, intensive antihypertensive treatment was shown to be beneficial only in cluster 4 (HR 0.73, 95% CI 0.55-0.98) and cluster 1 (HR 0.54, 95% CI 0.37-0.79) and was associated with an increased risk of severe adverse effects in cluster 2 (HR 1.18, 95% CI 1.05-1.32). CONCLUSION: Using a data-driven approach, SPRINT subjects can be stratified into four phenotypically distinct subgroups with different profiles on cardiovascular prognoses and responses to intensive antihypertensive treatment. Of note, these results should be taken as hypothesis generating that warrant further validation in future prospective studies.

Livin serves as a prognostic marker for mid-distal rectal cancer and a target of mid-distal rectal cancer treatment.

Livin is a novel member of the inhibitor of apoptosis protein family, which has been identified to be expressed in various malignancies and is suggested to be associated with poor prognostic significance. However, no data are available concerning the significance of livin in mid-distal rectal cancer. In the present study, livin expression, and its association with clinicopathological characteristics and prognosis was examined in patients with mid-distal rectal cancer. Apoptotic susceptibility, invasion capacity and chemosensitivity of LoVo cells were investigated using small interfering RNA (siRNA)-mediated knockdown of livin. It was revealed that livin was highly expressed in mid-distal rectal cancer tissues compared with the normal rectal mucosal tissues. Livin expression was associated with pathological grade, extent of invasion (T stage) and extent of lymph node metastasis (N stage) of tumor, contributing to poor prognosis of mid-distal rectal cancer following surgery. The data suggest that aggressive surgery should be applied in patients with mid-distal rectal cancer with high expression of livin. It was also revealed that knockdown of livin by siRNA increased the apoptotic rate, suppressed invasion of LoVo cells, and decreased the half-maximal inhibitory concentration of oxaliplatin and 5-fluorouracil by ~50% in LoVo cells significantly compared with control groups. The data suggested that a combination of downregulation of livin and anticancer drugs may significantly decrease the toxicity of anticancer drugs. Taken together, the present study indicated that livin may be a promising target in clinical therapy of mid-distal rectal cancer.

Design, synthesis, and antihypertensive activity of curcumin-inspired compounds via ACE inhibition and vasodilation, along with a bioavailability study for possible benefit in cardiovascular diseases.

This study describes the synthesis of a novel series of curcumin-inspired compounds via a facile synthetic route. The structures of these derivatives were ascertained using various spectroscopic and analytic techniques. The pharmacological effects of the target analogs were assessed by assaying their inhibition of angiotensin-converting enzyme (ACE). All of the synthesized derivatives exhibited considerable inhibition of ACE, with half-maximal inhibitory concentrations ranging from 1.23 to 120.32 µM. In a docking analysis with testicular ACE (tACE), the most promising inhibitor (4j) was efficiently accommodated in the deep cleft of the protein cavity, making close interatomic contacts with Glu162, His353, and Ala356, comparable with lisinopril. Compounds 4i, 4j, 4k, and 4l were further selected for determination of their vasodilator activity (cardiac output and stroke volume) on isolated rat hearts using the Langendorff technique. The bioavailability of compound 4j was determined in experimental mice.

Effect of low-dose glucocorticoid on corticosteroid insufficient patients with acute exacerbation of chronic obstructive pulmonary disease.

BACKGROUND: This study aimed to investigate the prevalence rate of critical illness-related corticosteroid insufficiency (CIRCI) and the effect of low-dose glucocorticoid on prognosis of CIRCI in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). METHODS: Since January 2010 to December 2012, 385 patients, who met the criteria of AECOPD, were enrolled in the Intensive Care Unit (ICU) of the First People's Hospital and Municipal Central Hospital of Xiangtan City. The AECOPD patients complicated with CIRCI screened by an adrenalcorticotrophic hormone test within 12 hours after admission to ICU were divided into a treatment group (n=32) and a control group (n=31) for a prospective, randomized and controlled clinical trial. Hydrocortisone (150 mg/d) or normal saline was injected intravenously for 7 days. The patients were followed up for 28 days after injection. The endpoint included 28-day survival time, non-shock time, ICU stay and the period of non-mechanical ventilation. The markers of inflammation C-reactive protein, tumor necrosis factor-α, interleukin 6 and procalcitonin were measured at baseline and 7 days after treatment. The variables were analyzed by Student's t test, the non-parametric statistical test, the Chi-square test or the Kaplan-Meier method with SPSS18.0 statistic software. A P value <0.05 was considered statistically significant. RESULTS: Totally 63 patients were diagnosed with CIRCI by an adrenalcorticotrophic hormone test and the prevalence rate was 16.4%. The shock rate of the AECOPD patients complicated with CIRCI was higher than that of the AECOPD patients without CIRCI (23.8% vs. 8.7%, P<0.01). Kaplan-Meier analysis revealed that the 28-day survival time of the treatment group was obviously longer than that of the control group (P<0.05). Compared with the control group, shock-free days within 28 days was longer in the treatment group (18.2±9.5 vs. 25.8±4.1, P<0.05). Treatment with low-dose glucocorticoid obviously decreased the markers of infection and inflammation (P<0.01), such as C-reactive protein (13.2±5.5 mg/L vs. 8.3±3.1 mg/L for the control group; 13.5±5.9 mg/L vs. 5.1±2.3 mg/L for the treatment group), tumor necrosis factor-α (26.1±16.2 µg/L vs. 17.5±11.7 µg/L for the control group; 25.0±14.8 µg/L vs. 10.4±7.8 µg/L for the treatment group) and procalcitonin (3.88 µg/L vs. 2.03 µg/L for the control group; 3.77 µg/L vs. 1.26 µg/L for the treatment group). Furthermore, the markers in the treatment group decreased more obviously than those in the control group (P<0.01). CONCLUSION: The prevalence rate of CIRCI was higher in the patients with AECOPD in the department of critical medicine, and low-dose glucocorticoid treatment for one week reduced the 28-day mortality, shock time and markers of infection and inflammation.

The role of red blood cell distribution width in mortality and cardiovascular risk among patients with coronary artery diseases: a systematic review and meta-analysis.

BACKGROUND: Red cell distribution width (RDW) might be a novel biomarker that reflects multiple physiological impairments related to atherosclerosis and coronary artery diseases (CAD). We conducted this systematic review and meta-analysis to evaluate the association of RDW between all-cause mortality and fatal/non-fatal cardiovascular disease (CVD) events in CAD patients. METHODS: Relevant studies were searched and identified in the MEDLINE and EMBASE databases. English-language prospective studies that reported risk estimates for RDW and mortality/CVD events were included. Data were extracted regarding the characteristics and clinical outcomes, and a quality assessment was conducted. Results were extracted for the highest versus lowest RDW level, and meta-analyses were carried out using random effects models. RESULTS: We identified 22 studies enrolling 80,216 participants. The study duration ranged between 1 month and 23 years. Of the 15 studies that were included in the meta-analysis, higher RDW indicated a significant increased risk for all-cause mortality in CAD patients: pooled risk ratio (RR) 2.20 (95% CI, 1.42-3.39; P<0.0004). The results for fatal, non-fatal and fatal/non-fatal events were: pooled RR 1.80 (95% CI, 1.35-2.41; P<0.0001), RR 1.86 (95% CI, 1.50-2.31; P<0.00001) and RR 2.13 (95% CI, 1.20-3.77; P=0.01). Heterogeneity was moderately present; however, sensitivity analyses for follow-up duration, CAD subtype, or RDW as dichotomous values showed similar results. CONCLUSIONS: The meta-analysis indicates that higher RDW levels are associated with increased risk of mortality and CVD events in patients with established CAD.

GYY4137, a novel hydrogen sulfide-releasing molecule, likely protects against high glucose-induced cytotoxicity by activation of the AMPK/mTOR signal pathway in H9c2 cells.

Diabetic cardiomyopathy (DCM) has become a major cause of diabetes-related morbidity and mortality. Increasing evidences have proved that hydrogen sulfide (H2S) fulfills a positive role in regulating diabetic myocardial injury. The present study was designed to determine whether GYY4137, a novel H2S-releasing molecule, protected H9c2 cells against high glucose (HG)-induced cytotoxicity by activation of the AMPK/mTOR signal pathway. H9c2 cells were incubated in normal glucose (5.5 mM), 22, 33, and 44 mM glucose for 24 h to mimic the hyperglycemia in DCM in vitro. Then we added 50, 100, and 200 µM GYY4137, and measured the cell viability, lactate dehydrogenase (LDH) enzyme activity, and mitochondrial membrane potential (MMP). 0.5 mM 5-amino-4-imidazole-carboxamide riboside (AICAR, an AMPK activator) and 1 mM adenine 9-ß-D-arabinofuranoside (Ara-A, an AMPK inhibitor) were used to identity whether the AMPK/mTOR signal pathway was involved in GYY4137-mediated cardioprotection. We demonstrated that HG decreased cell viability and increased LDH enzyme activity in a concentration-dependent manner. 33 mM HG treatment for 24 h was chosen as our model group for further study. Both 100 and 200 µM GYY4137 treatments significantly attenuated HG-induced cell viability decrement, LDH enzyme activity increase, and MMP collapse. AICAR had similar effects to GYY4137 treatment while Ara-A attenuated GYY4137-mediated cardioprotection. Importantly, both GYY4137 and AICAR increased AMPK phosphorylation and decreased mTOR phosphorylation compared with the HG model group while Ara-A attenuated GYY4137-mediated AMPK phosphorylation increase and mTOR phosphorylation decrement. In conclusion, we propose that GYY4137 likely protects against HG-induced cytotoxicity by activation of the AMPK/mTOR signal pathway in H9c2 cells.

Polysaccharide from Fuzi likely protects against starvation-induced cytotoxicity in H9c2 cells by increasing autophagy through activation of the AMPK/mTOR pathway.

There is increasing evidence that starvation induces autophagy, which may be protective during starvation, in an AMPK-dependent manner. Polysaccharides from Fuzi (FPS) reportedly have protective effects on nutrition-limited livers. The present study was designed to determine whether FPS protected H9c2 cells against starvation-induced cytotoxicity using an AMPK/mTOR-dependent mechanism. H9c2 cells were incubated in serum and glucose starvation media for 12 hours to establish a cell injury model. 3-Methyladenine (3MA, an autophagy inhibitor) was used to identify the exact role of autophagy in starvation. Cells were incubated with different FPS concentrations, and the cell injury levels, autophagy activity and AMPK/mTOR phosphorylation were measured. Adenine 9-ß-D-arabinofuranoside (Ara-A, an AMPK inhibitor) and 5-amino-4-imidazole-carboxamide riboside (AICAR, an AMPK activator) were used to identify whether the AMPK/mTOR pathway was involved in FPS-mediated cardioprotection. We demonstrated that starvation decreased cell viability in a time-dependent manner, and 3MA-induced autophagy inhibition aggravated the reduced cell viability. FPS treatment attenuated the cell viability decrement and the starvation-induced decline in the mitochondrial membrane potential (MMP), and autophagy; also, the AMPK/mTOR pathways were activated during treatment. Ara-A treatment abolished the protective effect of FPS, while AICAR treatment had a similar effect to FPS. We conclude that autophagy attenuates starvation-induced cardiomyocyte death, and FPS increases autophagy activity to protect against starvation-induced cytotoxicity in H9c2 cells, likely through AMPK/mTOR pathway activation.

[The effects of insulin and gliclazide therapy on endoplasmic reticulum stress and insulin sensitivity in liver of type 2 diabetic rats].

OBJECTIVE: To investigate the effect of insulin and gliclazide therapy on endoplasmic reticulum (ER) stress and insulin sensitivity in the liver of type 2 diabetic rats. METHODS: A high fat diet plus a low-dose of streptozotocin was implemented to create a type 2 diabetic rats which were randomly divided into diabetes mellitus (DM) group, insulin treatment (INS) group and gliclazide treatment (GT) group; and healthy rats were as normal control group. Diabetic rats in INS and GT groups were given neutral protamine hagedorn (NPH) insulin and gliclazide respectively for 3 weeks. Protein expression levels of immunoglobulin binding protein (Bip), spliced X-box binding protein 1 (XBP-1s), phosphorylated c-Jun on serine 73 (p-c-Jun), phosphorylated insulin receptor substrate 1 on serine 307 (p-IRS-1), and glucose-6-phosphatase (G6Pase) in liver homogenate were detected by Western blotting. RESULTS: Compared with the normal rats, Bip and XBP-1s in the DM group were up-regulated (0.28 ± 0.07 vs 0.90 ± 0.10 for Bip; 0.41 ± 0.07 vs 0.95 ± 0.07 for XBP-1s; both P < 0.01); p-c-Jun (0.59 ± 0.18 vs 1.94 ± 0.03), p-IRS-1 (1.73 ± 0.18 vs 5.32 ± 0.22) and G6Pase(0.11 ± 0.01 vs 0.45 ± 0.01) were increased (all P values < 0.01). In the INS group, all of aforementioned changes were reversed (0.90 ± 0.10 vs 0.25 ± 0.04 for Bip; 0.95 ± 0.07 vs 0.47 ± 0.01 for XBP-1s; 1.94 ± 0.03 vs 0.50 ± 0.10 for p-c-Jun; 5.32 ± 0.22 vs 1.59 ± 0.32 for p-IRS-1; 0.45 ± 0.01 vs 0.15 ± 0.02 for G6Pase, all P values < 0.01). In the GT group, all of aforementioned changes were also attenuated (0.90 ± 0.10 vs 0.53 ± 0.02 for Bip; 0.95 ± 0.07 vs 0.78 ± 0.02 for XBP-1s; 1.94 ± 0.03 vs 1.33 ± 0.11 for p-c-Jun; 5.32 ± 0.22 vs 3.13 ± 0.02 for p-IRS-1; 0.45 ± 0.01 vs 0.25 ± 0.01 for G6Pase, all P values < 0.05). Furthermore, all of aforementioned protein levels were down-regulated more obviously in the INS group comparing to the GT group (all P values < 0.01). CONCLUSIONS: Both insulin and gliclazide therapy could relieve ER stress and c-Jun N-terminal kinase activity and improved insulin sensitivity. The effect of insulin on Bip, XBP-1s, p-c-Jun, p-IRS-1 and G6Pase protein expressions is more obvious than that of gliclazide, which indicates besides lowering glucose, insulin might have protective effects of anti-inflammation, anti-oxidative stress or stimulation of lipid redistribution.