Anti-Toxoplasma gondii effect of tylosin in vitro and in vivo.

BACKGROUND: Toxoplasma gondii is an important protozoan pathogen with medical and veterinary importance worldwide. Drugs currently used for treatment of toxoplasmosis are less effective and sometimes cause serious side effects. There is an urgent need for the development of more effective drugs with relatively low toxicity. METHODS: The effect of tylosin on the viability of host cells was measured using CCK8 assays. To assess the inhibition of tylosin on T. gondii proliferation, a real-time PCR targeting the B1 gene was developed for T. gondii detection and quantification. Total RNA was extracted from parasites treated with tylosin and then subjected to transcriptome analysis by RNA sequencing (RNA-seq). Finally, murine infection models of toxoplasmosis were used to evaluate the protective efficacy of tylosin against T. gondii virulent RH strain or avirulent ME49 strain. RESULTS: We found that tylosin displayed low host toxicity, and its 50% inhibitory concentration was 175.3 µM. Tylsoin also inhibited intracellular T. gondii tachyzoite proliferation, with a 50% effective concentration of 9.759 µM. Transcriptome analysis showed that tylosin remarkably perturbed the gene expression of T. gondii, and genes involved in "ribosome biogenesis (GO:0042254)" and "ribosome (GO:0005840)" were significantly dys-regulated. In a murine model, tylosin treatment alone (100 mg/kg, i.p.) or in combination with sulfadiazine sodium (200 mg/kg, i.g.) significantly prolonged the survival time and raised the survival rate of animals infected with T. gondii virulent RH or avirulent ME49 strain. Meanwhile, treatment with tylosin significantly decreased the parasite burdens in multiple organs and decreased the spleen index of mice with acute toxoplasmosis. CONCLUSIONS: Our findings suggest that tylosin exhibited potency against T. gondii both in vitro and in vivo, which offers promise for treatment of human toxoplasmosis.

Treatment outcomes and cognitive function following electroconvulsive therapy in patients with severe depression.

BACKGROUND: Traditional treatments for major depressive disorder (MDD), including medication and therapy, often fail and have undesirable side effects. Electroconvulsive therapy (ECT) uses electrical currents to induce brief seizures in the brain, resulting in rapid and potent antidepressant effects. However, owing to misconceptions and controversies, ECT is not as widely used as it could and often faces stigmatization. AIM: To evaluate the efficacy and safety of ECT compared to those of medication and/or therapy in patients with severe MDD. METHODS: This prospective cohort study included 220 individuals with severe MDD who were divided into the ECT and non-ECT groups. The patients in the ECT group underwent bilateral ECT three times a wk until they either achieved remission or reached a maximum of 12 sessions. The non-ECT group received medication and/or therapy according to clinical guidelines for MDD. The primary outcome was the variation in the hamilton depression rating scale (HDRS) score from treatment/ECT initiation to week 12. In addition, patients' quality of life, cognitive abilities, and biomarkers were measured throughout the study. RESULTS: Although both groups showed significant improvements in their HDRS scores over time, the improvement was more pronounced in the ECT group than in the non-ECT group. Additionally, the ECT group exhibited a more substantial improvement in the quality of life and cognitive function than those of the non-ECT group. Compared with the non-ECT group, the ECT group exhibited evi-dently lower variations in the brain-derived neurotrophic factor (BDNF) and cytokine interleukin-6 (IL-6) levels. The side effects were generally mild and comparable between the two groups. ECT is safer and more potent than medication and/or therapy in mitigating depressive symptoms, enhancing well-being, and bolstering cognitive capabilities in individuals with severe MDD. ECT may also affect the levels of BDNF and IL-6, which are indicators of neuroplasticity and inflammation, respectively. CONCLUSION: ECT has emerged as a potentially advantageous therapeutic approach for patients with MDD who are unresponsive to alternative treatments.

Antimicrobial resistance in E. Coli of animal origin and discovery of a novel ICE mobile element in Northeast China.

BACKGROUND: Multidrug resistance in Enterobacteriaceae including resistance to quinolones is rising worldwide. The development of resistance may lead to the emergence of new transmission mechanisms. In this study, the collection of different E. coli was performed from animals and subjected to subsequent procedures including pulsed-field gel electrophoresis, micro-broth dilution method, polymerase chain reaction. Whole genome sequencing of E. coli C3 was performed to detect the affinity, antimicrobial resistance and major carriers of the isolates. RESULTS: A total of 66 E. coli were isolated and their antibiotic resistance genes, frequency of horizontal transfer and genetic environment of E. coli C3 were determined. The results showed there were both different and same types in PFGE typing, indicating clonal transmission of E. coli among different animals. The detection of antimicrobial resistance and major antibiotic resistance genes and the plasmid transfer results showed that strains from different sources had high levels of resistance to commonly used clinical antibiotics and could be spread horizontally. Whole-genome sequencing discovered a novel ICE mobile element. CONCLUSION: In summary, the antimicrobial resistance of E. coli in northeast China is a serious issue and there is a risk of antimicrobial resistance transmission. Meanwhile, a novel ICE mobile element appeared in the process of antimicrobial resistance formation.

Comprehensive analysis of mRNA-lncRNA co-expression profiles in mouse brain during infection with Toxoplasma gondii.

Toxoplasma gondii is an obligate intracellular protozoan parasite which seriously threatens the health of domestic animals and humans. Long non-coding RNAs (lncRNAs) are non-protein-coding transcripts greater than 200 nucleotides, which are widely involved in transcriptional and epigenetic regulations. However, little is known about the roles of host lncRNAs in the response to T. gondii infections. In this study, using Illumina sequencing technology, we analyzed the expression profiles of mRNAs and lncRNAs in BALB/c mouse brain following infection by T. gondii PRU strain (type II genotype) cysts. The identified differentially expressed (DE) RNAs were subjected to bioinformatics analysis. A total of 2,090 annotated lncRNAs along with 3,577 novel lncRNAs were identified. In the acutely infected mouse brain, a total of 330 mRNAs and 19 lncRNAs were dys-regulated, whereas 136 DE mRNAs and 9 DE lncRNAs were identified in chronically infected mouse brain. GO analysis revealed that these DE mRNAs identified at acute infection stage were involved in immune response, whereas DE mRNAs found at chronic infection stage were mostly enriched in response to protozoan. KEGG analysis showed that DE mRNAs were significantly enriched in disease related pathways. In addition, the putative mRNA-lncRNA co-expression network was constructed, and several hub regulatory RNAs were identified based on the transcriptome data. This study firstly characterized the co-expression profile of mRNAs and lncRNAs in mouse brain infected with T. gondii and provided a framework for further studies of the roles of lncRNAs in host neuropathology during toxoplasmosis progression.

Case report: A double pathogenic mutation in a patient with late-onset MELAS/PEO overlap syndrome.

Mitochondrial encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and progressive external ophthalmoplegia (PEO) are established phenotypes of mitochondrial disorders. They are maternally-inherited, multisystem disorder that is characterized by variable clinical, biochemical, and imaging features. We described the clinical and genetic features of a Chinese patient with late-onset MELAS/PEO overlap syndrome, which has rarely been reported. The patient was a 48-year-old woman who presented with recurrent ischemic strokes associated with characteristic brain imaging and bilateral ptosis. We assessed her clinical characteristics and performed mutation analyses. The main manifestations of the patient were stroke-like episodes and seizures. A laboratory examination revealed an increased level of plasma lactic acid and a brain MRI showed multiple lesions in the cortex. A muscle biopsy demonstrated ragged red fibers. Genetic analysis from a muscle sample identified two mutations: TL1 m.3243A>G and POLG c.3560C>T, with mutation loads of 83 and 43%, respectively. This suggested that mitochondrial disorders are associated with various clinical presentations and an overlap between the syndromes and whole exome sequencing is important, as patients may carry multiple mutations.

Simulation of primary current distribution in Tesla-type pulse generators.

In a Tesla-type pulse generator, self-inductance of the primary coil is a crucial parameter to determine the final oscillating condition. However, the accurate value of this inductance might be changed due to the uneven primary current distribution caused by practical configuration of the primary side. Consequently, in order to precisely design the transformer, it is helpful to evaluate the primary inductance based on electromagnetic simulation instead of conventional approximate calculation. In this paper, a simulation model based on the finite integration technique is established to solve the uneven primary current problem. A primary coil with multiple contacting points is designed, and hexahedral mesh generation of the coil is also discussed. Hence, a series of verification tests using different primary structures are performed to support the results of simulation. Both results of the simulation model and the verification test presented that the variation of the primary inductance will affect the performance of the generator, and the number of contacting points is the main cause to determine the maximum current density of the coil.

Optineurin promotes myogenesis during muscle regeneration in mice by autophagic degradation of GSK3ß.

Skeletal muscle regeneration is essential for maintaining muscle function in injury and muscular disease. Myogenesis plays key roles in forming new myofibers during the process. Here, through bioinformatic screen for the potential regulators of myogenesis from 5 independent microarray datasets, we identify an overlapping differentially expressed gene (DEG) optineurin (OPTN). Optn knockdown (KD) delays muscle regeneration in mice and impairs C2C12 myoblast differentiation without affecting their proliferation. Conversely, Optn overexpression (OE) promotes myoblast differentiation. Mechanistically, OPTN increases nuclear levels of ß-catenin and enhances the T-cell factor/lymphoid enhancer factor (TCF/LEF) transcription activity, suggesting activation of Wnt signaling pathway. The activation is accompanied by decreased protein levels of glycogen synthase kinase 3ß (GSK3ß), a negative regulator of the pathway. We further show that OPTN physically interacts with and targets GSK3ß for autophagic degradation. Pharmacological inhibition of GSK3ß rescues the impaired myogenesis induced by Optn KD during muscle regeneration and myoblast differentiation, corroborating that GSK3ß is the downstream effector of OPTN-mediated myogenesis. Together, our study delineates the novel role of OPTN as a potential regulator of myogenesis and may open innovative therapeutic perspectives for muscle regeneration.

LYAR promotes the proliferation of non-small cell lung cancer and is associated with poor prognosis.

INTRODUCTION: The aim of the study was to investigate the clinical significance of Ly-1 antibody reactive clone (LYAR) in non-small-cell lung cancer (NSCLC). MATERIAL AND METHODS: The expressions of LYAR at the protein level in representative paired NSCLC tumor tissues and adjacent non-tumor tissues were measured by Western blot and immunohistochemistry. Kaplan-Meier method was used to calculate the survival curve of patients with NSCLC. Cell Counting Kit-8 assay and flow cytometry were used to estimate the cell proliferation and cell cycle, respectively. Terminal-deoxynucleotidyl-transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay was performed to detect cell apoptosis. RESULTS: LYAR was dramatically overexpressed in NSCLC tissues which were closely related to the survival of patients with NSCLC. In clinical studies, the expression of LYAR was related to the clinical stage, histological differentiation, and Ki-67 expression. A positive correlation was found between LYAR and Ki-67 expression by Spearman's correlation test. After serum starvation for 72 h, serum re-addition significantly increased the expression of LYAR, PCNA, and Cyclin A and promoted the cell cycle progression. LYAR knockdown inhibited the proliferation and induced the G0/G1 cell cycle arrest and apoptosis of A549 cells. CONCLUSIONS: The present study revealed the clinical significance of LYAR in NSCLC. LYAR might serve as a tumor promoter in NSCLC progression by promoting the proliferation and inhibiting the apoptosis of NSCLC cells. Inhibiting the expression of LYAR was considered as a potential novel therapeutic strategy for NSCLC.

Antimicrobial Natural Products Produced by Soil-Derived Fungus Penicillium cremeogriseum W1-1.

Ten compounds (1-10) were obtained from soil-derived Penicillium cremeogriseum W1-1 with the antimicrobial guided isolation procedure. Among them, 4 presented broad-spectrum antimicrobial activities and its preliminary mechanisms were evaluated. Compound 4 showed growth inhibition on drug-resistant pathogenic strains Escherichia coli and Candida albicans with post-contact effect (PCE), changed the morphology and membrane structure, killed cells with leakage, inhibited the growth of C. albicans by eradicating biofilms. Interestingly, the fraction containing 4 presented in vivo anti-pathogenic activities in mice, indicating this indole diterpenoid alkaloid could been used as potential antimicrobial agent.

Koninginin W, a New Polyketide from the Endophytic Fungus Trichoderma koningiopsis YIM PH30002.

A new compound named koninginin W (1) and four known polyketides (2-5) were isolated from endophytic fungus Trichoderma koningiopsis YIM PH30002 of Panax notoginseng. The structures of 1 - 5, including absolute configuration of 1, were elucidated on the detailed analysis of the HR-ESI-MS, 1D and 2D NMR, and X-ray crystallographic data. Koninginin W (1) presented weak antibacterial activity against Escherichia coli, Bacillus subtilis and Salmonella typhimurium.

Potent Antihyperuricemic Triterpenoids Based on Two Unprecedented Scaffolds from the Leaves of Alstonia scholaris.

Two rearranged triterpenoids, representing new subtypes of pentacyclic triterpenoids, with unique 6/6/6/7/5 and 6/6/5/6/6/6 ring systems were isolated from Alstonia scholaris. Their structures were established by spectroscopic analysis, single-crystal X-ray diffraction, and electronic circular dichroism calculations. Both compounds exhibited potent antihyperuricemic bioactivity in vitro and in vivo.

Myrothins A-F from Endophytic Fungus Myrothecium sp. BS-31 Harbored in Panax notoginseng.

Endophytic fungi play important roles for host's stress tolerance including invasion by pathogenic microbes. Small molecules are common weapons in the microbe-microbe interactions. Panax notoginseng is a widely used traditional Chinese medicinal plant and harbors many endophytes, some exert functions against pathogens. Here, we report six new compounds named myrothins A-F (1-6) produced by Myrothecium sp. BS-31, an endophyte isolated from P. notoginseng, and their antifungal activities against pathogenic fungi causing host root-rot disease. Their structures were elucidated with analysis of spectroscopic data including 1D and 2D NMR, HR-ESI-MS. Myrothins B (2) and E (5) showed the weak activity against Fusarium oxysporum and Phoma herbarum, and myrothins F (6) showed weak activity against F. oxysporum.

Serine protease inhibitor MDSPI16 ameliorates LPS-induced acute lung injury through its anti-inflammatory activity.

A previous study described a novel serine protease inhibitor 16 from Musca domestica (MDSPI16), which inhibited the elastase and chymotrypsin. It also exhibited a potential anti-inflammatory activity for acute lung injury (ALI), while its effects on ALI are yet to be elucidated. The present study aimed to investigate the effects and the underlying mechanisms of MDSPI16 on lipopolysaccharide (LPS)-challenged mice and bone marrow neutrophils. The ALI model based on the results of LPS-induced mice demonstrated that MDSPI16 markedly reduced the infiltration of inflammatory cells, protein exudation in lung tissues, and downregulated the level of interleukin-6 (IL-6), IL-1ß and tumor necrosis factor-α (TNF-α). Furthermore, the LPS-stimulated mouse bone marrow neutrophils model was employed to determine the role of MDSPI16. The cytokine levels were quantified by both the enzyme-linked immunosorbent assay (ELISA) and quantitative real-time polymerase chain reaction (qRT-PCR). Consequently, the expression of IL-6, IL-1ß, and TNF-α was found to be inhibited by MDSPI16 in a dose-dependent manner. Moreover, MDSPI16 also inhibited the mouse neutrophils nuclear factor-κB (NF-κB) signaling pathway, c-Jun N-terminal kinase (JNK) signaling pathway, ERK1/2 and AP-1 signaling pathway in addition to the expression of iNOS and COX-2 proteins, which in turn, might alleviate the release of pro-inflammatory cytokines during ALI. Therefore, MDSPI16 could be proposed as a potential and novel drug therapy for ALI.

Homogeneous nanodiscs of native membranes formed by stilbene-maleic-acid copolymers.

Methylstilbene-alt-maleic acid copolymers spontaneously convert biological membranes into bilayer discs with ∼20 nm diameters. This readily functionalizable class of copolymers has the compositional homogeneity, hydrophobicity, dynamics, and charge that may help to achieve optimal structural resolution, membrane dissolution, stability, and broad utility.

Neohesperidin attenuates obesity by altering the composition of the gut microbiota in high-fat diet-fed mice.

Obesity and related metabolic disorders are associated with intestinal microbiota dysbiosis, disrupted intestinal barrier, and chronic inflammation. Neohesperidin (Neo), a natural polyphenol abundant in citrus fruits, is known for its preventative and therapeutic effects on numerous diseases. Here, we report that Neo administration attenuates weight gain, low-grade inflammation, and insulin resistance in mice fed high-fat diet (HFD). Also, Neo administration substantially restores gut barrier damage, metabolic endotoxemia, and systemic inflammation. Sequencing of 16S rRNA genes in fecal samples revealed that Neo administration reverses HFD-induced intestinal microbiota dysbiosis: an increase in the diversity of gut microbiota and alteration in the composition of intestinal microbiota (particularly in the relative abundances of Bacteroidetes and Firmicutes). Furthermore, systemic antibiotic treatment abolishes the beneficial effects of Neo in body weight control, suggesting that the effect of Neo on obesity attenuation largely depends on the gut microbiota. More importantly, we demonstrate that the impact of Neo on the regulation of obesity could be transferred from Neo-treated mice to HFD-fed mice via fecal microbiota transplantation. Collectively, our data highlight the efficacy of Neo as a prebiotic agent for attenuating obesity, implying a potential mechanism for gut microbiota mediated the beneficial effect of Neo.

Mitochondrial aconitase controls adipogenesis through mediation of cellular ATP production.

Mitochondrial aconitase (Aco2) catalyzes the conversion of citrate to isocitrate in the TCA cycle, which produces NADH and FADH2, driving synthesis of ATP through OXPHOS. In this study, to explore the relationship between adipogenesis and mitochondrial energy metabolism, we hypothesize that Aco2 may play a key role in the lipid synthesis. Here, we show that overexpression of Aco2 in 3T3-L1 cells significantly increased lipogenesis and adipogenesis, accompanied by elevated mitochondrial biogenesis and ATP production. However, when ATP is depleted by rotenone, an inhibitor of the respiratory chain, the promotive role of Aco2 in adipogenesis is abolished. In contrast to Aco2 overexpression, deficiency of Aco2 markedly reduced lipogenesis and adipogenesis, along with the decreased mitochondrial biogenesis and ATP production. Supplementation of isocitrate efficiently rescued the inhibitory effect of Aco2 deficiency. Similarly, the restorative effect of isocitrate was abolished in the presence of rotenone. Together, these results show that Aco2 sustains normal adipogenesis through mediating ATP production, revealing a potential mechanistic link between TCA cycle enzyme and lipid synthesis. Our work suggest that regulation of adipose tissue mitochondria function may be a potential way for combating abnormal adipogenesis related diseases such as obesity and lipodystrophy.

A Potential Nutraceutical Candidate Lactucin Inhibits Adipogenesis through Downregulation of JAK2/STAT3 Signaling Pathway-Mediated Mitotic Clonal Expansion.

The prevalence of obesity has increased dramatically worldwide in the past ~50 years. Searching for safe and effective anti-obesity strategies are urgently needed. Lactucin, a plant-derived natural small molecule, is known for anti-malaria and anti-hyperalgesia. The study is to investigate whether lactucin plays a key role in adipogenesis. To this end, in vivo male C57BL/6 mice fed a high-fat diet (HFD) were treated with 20 mg/kg/day of lactucin or vehicle by gavage for seven weeks. Compared with vehicle-treated controls, Lactucin-treated mice showed lower body mass and mass of adipose tissue. Consistently, in vitro 3T3-L1 cells were treated with 20 µM of lactucin. Compared to controls, lactucin-treated cells showed significantly less lipid accumulation during adipocyte differentiation and lower levels of lipid synthesis markers. Mechanistically, we showed the anti-adipogenic property of lactucin was largely limited to the early stage of adipogenesis. Lactucin-treated cells fail to undergo mitotic clonal expansion (MCE). Further studies demonstrate that lactucin-induced MCE arrests might result from reduced phosphorylation of JAK2 and STAT3. We then asked whether activation of JAK2/STAT3 would restore the inhibitory effect of lactucin on adipogenesis with pharmacological STAT3 activator colivelin. Our results revealed similar levels of lipid accumulation between lactucin-treated cells and controls in the presence of colivelin, indicating that inactivation of STAT3 is the limiting factor for the anti-adipogenesis of lactucin in these cells. Together, our results provide the indication that lactucin exerts an anti-adipogenesis effect, which may open new therapeutic options for obesity.

Overexpression of microRNA-590-3p promotes the proliferation of and inhibits the apoptosis of myocardial cells through inhibition of the NF-κB signaling pathway by binding to RIPK1.

Ischemic heart disease is widely considered as a major health threat, which causes a high number of deaths every year worldwide. Much evidence has shown that oxidative stress (OS) is implicated in the pathogenesis of ischemia-reperfusion injury (IRI). This study aims to evaluate the effect of miR-590-3p on the OS of IRI mice through the nuclear factor kappa-B (NF-κB) signaling pathway by targeting receptor-interacting protein kinase 1 (RIPK1). IRI mouse models were established for extracting myocardial tissues and isolating myocardial cells. The expression of inflammatory related-factors was detected by enzyme-linked immunosorbent assay, and superoxide dismutase (SOD) and malondialdehyde (MDA) in tissues were determined. Reverse transcription quantitative polymerase chain reaction and Western blot analysis were performed to assess the role of miR-590-3p in the expression of NF-κB-related factors and apoptosis-related factors. Besides, the regulatory effects of miR-590-3p on myocardial cell proliferation and apoptosis were also assessed. According to the obtained results, we found that IRI mice displayed higher expression of tumor necrosis factor-α, interleukin (IL)-6, and interferon-γ, lower expression of IL-10 in serum, a decreased SOD level, and an increased MDA level. In addition, RIPK1 was determined as a target gene of miR-590-3p. After transfection of overexpressed miR-590-3p or si-RIPK1, declined RIPK1, NF-κB, Toll-like receptor 4, caspase-3, FasL, p53, and c-myc levels, increased B-cell lymphoma-2 level, promoted cell proliferation, promoted cell cycle distribution and inhibited apoptosis of myocardial cells were found. Our study demonstrates that miR-590-3p can alleviate the OS of IRI mice through the inhibition of the RIPK1 and NF-κB signaling pathway. Thus, miR-590-3p represents a potential target for IRI repair.

[Experimental study of a new animal model with trigeminal neuralgia produced by administration of talc to peripheral infraobital nerve in rats].

PURPOSE: To establish a new animal model of trigeminal neuralgia（TN） produced by administration of talc to peripheral infraobital nerve in rats. METHODS: Thirty male Wistar rats were randomly divided into 2 groups. Talcum powder (30％,0.3 mL) was injected into the peripheral infraorbital foramen in one group, the same dose of normal saline was injected by the same method in another group. On 3 day before surgery and 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 6 weeks, 8 and 12 weeks postoperatively, mechanical pain behavior was determined. Statistical analysis of the threshold of pain response was performed and the behavior of pain was observed in the area of infraorbital nerve innervation in rats. Histopathological changes of the peripheral infraorbital nerve tissue in the rats were observed 3 days, 4 weeks, 8 weeks and 12 weeks postoperatively. The expression of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukin -1ß (IL-1ß) in the territory of the infraorbital nerve was detected by immunohistochemistry. SPSS16.0 software package was used to analyze the data. RESULTS: The mechanical pain threshold of rats in the infraorbital innervation area 3 days postoperatively in the experimental group was significantly decreased compared with that in the preoperative group and the control group (P<0.01). The rats in the experimental group 3 days postoperatively experienced symptoms of irritability, scratching the face or aggressive behavior. Twelve weeks after operation, the mechanical pain threshold was still significantly decreased. Histopathological examination in the experimental group 3 days postoperatively mainly showed inflammation with a few inflammatory factors（IL-1ß and TNF-α）expression. Inflammation in the experimental group 1week postoperatively was more intense and more inflammatory factors were expressed. Four weeks postoperatively, there was more proliferation of granulation tissue in the area of peripheral infraorbital nerve tissue and expression of inflammatory factors was highest. Four to twelve weeks, the inflammatory response in the experimental group was gradually reduced, increased scar and infraorbital nerve compressing by scar were observed, and the expression of inflammatory factors decreased gradually. CONCLUSIONS: Injection of talc to the peripheral infraorbital foramen can establish a reliable and stable animal model for research of etiology and treatment of TN.

Attenuation of High Glucose-Induced Rat Cardiomyocyte Apoptosis by Exendin-4 via Intervention of HO-1/Nrf-2 and the PI3K/AKT Signaling Pathway.

Exendin-4, a glucagon-like peptide-1 receptor agonist, demonstrated cytoprotective actions beyond glycemic control in recent studies. The aims of the present study were to investigate the effects of exendin-4 on high glucose (HG)-induced cardiomyocyte apoptosis and the possible mechanisms. Rat cardiomyocytes were divided into 3 groups: normal glucose group (NG group), HG group and HG +exendin-4 group (HG+Ex Group). Cardiomyocyte apoptosis was evaluated by double-staining with annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) and flow cytometry. Intracellular reactive oxygen species (ROS) production was detected by 2',7'-dichlorodihydrofluorescein diacetate (DCHF-DA) incubation and fluorescence microscopy. LY294002 (LY), a phosphoinositide 3-kinase (PI3K) pathway inhibitor, was added to the medium of the HG+Ex+LY Group for further western blot analysis. The proteins analyzed involved oxidative stress-associated proteins, heme oxygenase-1 (HO-1) and nuclear factor E2-related factor 2 (Nrf-2), and apoptosis-associated proteins, caspase-3, Bax/B-cell lymphoma 2 (Bcl-2) and p-AKT/AKT. HG treatment induced cardiomyocyte apoptosis (P = 0.00) and clearly upregulated ROS production (P = 0.00); exendin-4 co-incubation also ameliorated cardiomyocyte apoptosis (P = 0.004) and decreased ROS (P = 0.00) level significantly. HO-1 and Nrf-2 protein expression levels decreased significantly in the HG group (P < 0.05), but the levels were elevated by exendin-4 intervention (P < 0.05). Furthermore, exendin-4 attenuated HG-induced higher protein expression, including cleaved caspase-3 and Bax, increased the expression of Bcl-2 protein (P < 0.05). However, these impacts of exendin-4 were counteracted significantly by co-incubation with LY294002. In addition, exendin-4 ameliorated HG-induced p-AKT/AKT lower expression, and this impact was also suppressed by LY294002. Exendin-4 ameliorates HG-induced cardiomyocyte apoptosis, and the mechanisms may involve anti-oxidative stress via the HO-1/Nrf-2 system, as well as intervention of the PI3K/AKT signaling pathway.