Myocardial Oxidative Stress Research Articles

MicroRNA-322-5p targeting Smurf2 regulates the TGF-β/Smad pathway to protect cardiac function and inhibit myocardial infarction.

Acute coronary artery blockage leads to acute myocardial infarction (AMI). Cardiomyocytes are terminally differentiated cells that rarely divide. Treatments preventing cardiomyocyte loss during AMI have a high therapeutic benefit. Accumulating evidence shows that microRNAs (miRNAs) may play an essential role in cardiovascular diseases. This study aims to explore the biological function and underlying regulatory molecular mechanism of miR-322-5p on myocardial infarction (MI). This study's miR-322-5p is downregulated in MI-injured hearts according to integrative bioinformatics and experimental analyses. In the MI rat model, miR-322-5p overexpression partially eliminated MI-induced changes in myocardial enzymesand oxidative stress markers, improved MI-caused impairment on cardiac functions, inhibited myocardial apoptosis, attenuated MI-caused alterations in TGF-β, p-Smad2, p-Smad4, and Smad7 protein levels. In oxygen-glucose deprivation (OGD)-injured H9c2 cells, miR-322-5p overexpression partially rescued OGD-inhibited cell viability and attenuated OGD-caused alterations in the TGF-β/Smad signaling. miR-322-5p directly targeted Smurf2 and inhibited Smurf2 expression. In OGD-injured H9c2 cells, Smurf2 knockdown exerted similar effects to miR-322-5p overexpression upon cell viability and TGF-β/Smad signaling; moreover, Smurf2 knockdown partially attenuated miR-322-5p inhibition effects on OGD-injured H9c2 cells. In conclusion, miR-322-5p is downregulated in MI rat heart and OGD-stimulated rat cardiomyocytes; the miR-322-5p/Smurf2 axis improves OGD-inhibited cardiomyocyte cell viability and MI-induced cardiac injuries and dysfunction through the TGF-β/Smad signaling.

Dapagliflozin ameliorates myocardial infarction injury through AMPKα-dependent regulation of oxidative stress and apoptosis

Dapagliflozin (DAPA) has been demonstrated to reduce cardiovascular mortality and heart failure hospitalization rates in diabetic patients. However, the mechanism underlying its cardio-protective effect in non-diabetic patients remains unclear. Our study aimed to explore the cardio-protective impact of DAPA on myocardial infarction in non-diabetic mice. We induced myocardial infarction in C57BL/6 mice by ligating the descending branch of the left coronary artery. After surgery, the animals were randomly treated with either saline or DAPA. We employed echocardiography, Western blot analysis, and tissue staining to assess post-infarction myocardial injury. Additionally, we investigated the mechanism of action through cell experiments. Compared to the myocardial infarction group, DAPA treatment significantly attenuated ventricular remodeling and improved cardiac function. By mitigating myocardial oxidative stress and apoptosis, DAPA may activate the AMPKα signaling pathway, thereby exerting a protective effect. These findings suggest that DAPA could serve as a novel therapeutic approach for patients with cardiac infarction.

NADPH oxidase 2 mediates cardiac sympathetic denervation and myocyte autophagy, resulting in cardiac atrophy and dysfunction in doxorubicin-induced cardiomyopathy

Doxorubicin has been used extensively as a potent anticancer agent, but its clinical use is limited by its cardiotoxicity. However, the underlying mechanisms remain to be fully elucidated. In this study, we tested whether NADPH oxidase 2 (Nox2) mediates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy, resulting in cardiac atrophy and dysfunction in doxorubicin-induced heart failure. Nox2 knockout (KO) and wild-type (WT) mice were randomly assigned to receive a single injection of doxorubicin (15 mg/kg, i.p.) or saline. WT doxorubicin mice exhibited the decreases in survival rate, left ventricular (LV) wall thickness and LV fractional shortening and the increase in the lung wet-to-dry weight ratio 1 week after the injections. These alterations were attenuated in Nox2 KO doxorubicin mice. In WT doxorubicin mice, myocardial oxidative stress was increased, myocardial noradrenergic nerve fibers were reduced, myocardial expression of PGP9.5, GAP43, tyrosine hydroxylase and norepinephrine transporter was decreased, and these changes were prevented in Nox2 KO doxorubicin mice. Myocyte autophagy was increased and myocyte size was decreased in WT doxorubicin mice, but not in Nox2 KO doxorubicin mice. Nox2 mediates cardiac sympathetic nerve terminal abnormalities and myocyte autophagy—both of which contribute to cardiac atrophy and failure after doxorubicin treatment.

MCT4-dependent lactate transport: a novel mechanism for cardiac energy metabolism injury and inflammation in type 2 diabetes mellitus

Diabetic cardiomyopathy (DCM) is a major contributor to mortality in diabetic patients, characterized by a multifaceted pathogenesis and limited therapeutic options. While lactate, a byproduct of glycolysis, is known to be significantly elevated in type 2 diabetes, its specific role in DCM remains uncertain. This study reveals an abnormal upregulation of monocarboxylate transporter 4 (MCT4) on the plasma membrane of cardiomyocytes in type 2 diabetes, leading to excessive lactate efflux from these cells. The disruption in lactate transport homeostasis perturbs the intracellular lactate-pyruvate balance in cardiomyocytes, resulting in oxidative stress and inflammatory responses that exacerbate myocardial damage. Additionally, our findings suggest increased lactate efflux augments histone H4K12 lactylation in macrophages, facilitating inflammatory infiltration within the microenvironment. In vivo experiments have demonstrated that inhibiting MCT4 effectively alleviates myocardial oxidative stress and pathological damage, reduces inflammatory macrophage infiltration, and enhances cardiac function in type 2 diabetic mice. Furthermore, a clinical prediction model has been established, demonstrating a notable association between peripheral blood lactate levels and diastolic dysfunction in individuals with type 2 diabetes. This underscores the potential of lactate as a prognostic biomarker for DCM. Ultimately, our findings highlight the pivotal involvement of MCT4 in the dysregulation of cardiac energy metabolism and macrophage-mediated inflammation in type 2 diabetes. These insights offer novel perspectives on the pathogenesis of DCM and pave the way for the development of targeted therapeutic strategies against this debilitating condition.

Nicotinamide ribose ameliorates myocardial ischemia/reperfusion injury by regulating autophagy and regulating oxidative stress.

Nicotinamide riboside (NR) has been reported to play a protective role in myocardial ischemia-reperfusion (I/R) injury when used in association with other drugs; however, the individual effect of NR is unknown. In the present study Evan's blue/triphenyl tetrazolium chloride staining, hematoxylin and eosin staining, echocardiography, western blotting, reverse transcription-quantitative PCR, and the detection of myocardial injury-associated markers and oxidative stress metabolites were used to explore the ability of NR to alleviate cardiac I/R injury and the relevant mechanisms of action. In a mouse model of I/R injury, dietary supplementation with NR reduced the area of myocardial ischemic infarction, alleviated pathological myocardial changes, decreased inflammatory cell infiltration and attenuated the levels of mitochondrial reactive oxygen species (ROS) and creatine kinase myocardial band (CK-MB). In addition, echocardiography suggested that NR alleviated the functional damage of the myocardium caused by I/R injury. In H9c2 cells, NR pretreatment reduced the levels of lactate dehydrogenase, CK-MB, malondialdehyde, superoxide dismutase and ROS, and reduced cell mortality after the induction of hypoxia/reoxygenation (H/R) injury. In addition, the results indicated NR activated sirt 1 via the upregulation of nicotinamide adenine dinucleotide (NAD+) and protected the cells against autophagy. The sirt 1 inhibitor EX527 significantly attenuated the ability of NR to inhibit autophagy, but had no significant effect on the ROS content of the H9c2 cells. In summary, the present study suggests that NR protects against autophagy by increasing the NAD+ content in the body via the sirt 1 pathway, although the sirt 1 pathway does not affect oxidative stress.

Role of mesenchymal stem cells-derived exosomes on inflammation, apoptosis, fibrosis and telocyte modulation in doxorubicin-induced cardiotoxicity: A closer look at the structural level.

Cardiotoxicity induced by doxorubicin (Dox) is a major complication in cancer patients. Exosomes (Ex) derived from mesenchymal cells could be a promising therapeutic for various heart diseases. This study investigated the role of Ex in Dox-induced cardiotoxicity and its mechanistic insights, using Sacubitril/valsartan (S/V) as a reference drug widely recommended in heart failure management. The study involved 24 Wistar rats, divided into a control, Dox, Dox + S/V, and Dox + Ex groups. The rats were assessed for cardiac enzymes, inflammatory and oxidative stress markers. Immunohistochemical expression of caspase-1, nuclear factor erythroid 2-related factor 2 (NrF2), E-Cadherin, CD117/c-kit, and Platelet-derived growth factor-α (PDGFα) was evaluated. P53 and Annexin V were assessed by PCR. Histological examination was performed using hematoxylin and eosin and Sirius red stains. Ex ameliorated the adverse cardiac pathological changes and significantly decreased the cardiac enzymes and inflammatory and oxidative stress markers. Ex also exerted antifibrotic and antiapoptotic effect in heart tissue. Ex treatment also improved NrF2 immunohistochemistry, up-regulated E-Cadherin immune expression, and restored the telocyte markers CD117/c-kit and PDGFα. Ex can mitigate Dox-induced cardiotoxicity by acting as an anti-inflammatory, antioxidant, antiapoptotic, and antifibrotic agents, restoring telocytes and modulating epithelial mesenchymal transition. RESEARCH HIGHLIGHTS: Exosomes exhibit positive expression for CD90 and CD105 whereas showing -ve expression for CD 34 by flow cytometry. Exosomes restore the immunohistochemical expression of the telocytes markers CD117/c-kit and PDGFα. Exosomes alleviate myocardial apoptosis, oxidative stress and fibrosis.

Chaihu Sanshen Capsules protect rats from myocardial ischemia reperfusion injury via PKCβⅡ/NOX2/ROS signaling pathway

This study aims to explore the pathogenesis of myocardial ischaemia reperfusion injury(MIRI) based on oxidative stress-mediated programmed cell death and the mechanism and targets of Chaihu Sanshen Capsules in treating MIRI via the protein kinase Cβ(PKCβⅡ)/NADPH oxidase 2(NOX2)/reactive oxygen species(ROS) signaling pathway. The rat model of MIRI was established by the ligation of the left anterior descending branch. Rats were randomized into 6 groups: sham group, model group, clinically equivalent-, high-dose Chaihu Sanshen Capsules groups, N-acetylcysteine group, and CGP53353 group. After drug administration for 7 consecutive days, the area of myocardial infarction in each group was measured. The pathological morphology of the myocardial tissue was observed by hematoxylin-eosin(HE) staining. The apoptosis in the myocardial tissue was observed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling(TUNEL). Enzyme-linked immunosorbent assay(ELISA) was employed to measure the le-vels of indicators of myocardial injury and oxidative stress. The level of ROS was detected by flow cytometry. The protein and mRNA levels of the related proteins in the myocardial tissue were determined by Western blot and real-time quantitative PCR(RT-qPCR), respectively. Compared with the sham group, the model group showed obvious myocardial infarction, myocardial structural disorders, interstitial edema and hemorrhage, presence of a large number of vacuoles, elevated levels of myocardial injury markers, myocardial apoptosis, ROS, and malondialdehyde(MDA), lowered superoxide dismutase(SOD) level, and up-regulated protein and mRNA le-vels of PKCβⅡ, NOX2, cysteinyl aspartate specific proteinase-3(caspase-3), and acyl-CoA synthetase long-chain family member 4(ACSL4) in the myocardial tissue. Compared with the model group, Chaihu Sanshen Capsules reduced the area of myocardial infarction, alleviated the pathological changes in the myocardial tissue, lowered the levels of myocardial injury and oxidative stress indicators and apoptosis, and down-regulated the mRNA and protein levels of PKCβⅡ, NOX2, caspase-3, and ACSL4 in the myocardial tissue. Chaihu Sanshen Capsules can inhibit oxidative stress and programmed cell death(apoptosis, ferroptosis) by regulating the PKCβⅡ/NOX2/ROS signaling pathway, thus mitigating myocardial ischemia reperfusion injury.

Aucubin alleviates doxorubicin-induced cardiotoxicity through crosstalk between NRF2 and HIPK2 mediating autophagy and apoptosis

BackgroundDoxorubicin (DOX) is widely used for the treatment of a variety of cancers. However, its clinical application is limited by dose-dependent cardiotoxicity. Recent findings demonstrated that autophagy inhibition and apoptosis of cardiomyocytes induced by oxidative stress dominate the pathophysiology of DOX-induced cardiotoxicity (DIC), however, there are no potential molecules targeting on these. PurposeThis study aimed to explore whether aucubin (AU) acting on inimitable crosstalk between NRF2 and HIPK2 mediated the autophagy, oxidative stress, and apoptosis in DIC, and provide a new and alternative strategy for the treatment of DIC. Methods and ResultsWe first demonstrated the protection of AU on cardiac structure and function in DIC mice manifested by increased EF and FS values, decreased serum CK-MB and LDH contents and well-aligned cardiac tissue in HE staining. Furthermore, AU alleviated DOX-induced myocardial oxidative stress, mitochondrial damage, apoptosis, and autophagy flux dysregulation in mice, as measured by decreased ROS, 8-OHdG, and TUNEL-positive cells in myocardial tissue, increased SOD and decreased MDA in serum, aligned mitochondria with reduced vacuoles, and increased autophagosomes. In vitro, AU alleviated DOX-induced oxidative stress, autophagy inhibition, and apoptosis by promoting NRF2 and HIPK2 expression. We also identified crosstalk between NRF2 and HIPK2 in DIC as documented by overexpression of NRF2 or HIPK2 reversed cellular oxidative stress, autophagy blocking, and apoptosis aggravated by HIPK2 or NRF2 siRNA, respectively. Simultaneously, AU promoted the expression and nuclear localization of NRF2 protein, which was reversed by HIPK2 siRNA, and AU raised the expression of HIPK2 protein as well, which was reversed by NRF2 siRNA. Crucially, AU did not affect the antitumor activity of DOX against MCF-7 and HepG2 cells, which made up for the shortcomings of previous anti-DIC drugs. ConclusionThese collective results innovatively documented that AU regulated the unique crosstalk between NRF2 and HIPK2 to coordinate oxidative stress, autophagy, and apoptosis against DIC without compromising the anti-tumor effect of DOX in vitro.

Colchicine alleviates myocardial ischemia-reperfusion injury in mice by activating AMPK

To investigate the protective effect of colchicine against myocardial ischemia-reperfusion injury (I/R) and explore the underlying mechanism. H9C2 cells exposed to hypoxia/reoxygenation (H/R) were treated with 3 nmol/L colchicine, after which the changes in cell viability were assessed using MTT assay, and AMPK phosphorylation, the expressions of NOX4, NRF2, SOD2, BAX, Bcl-2, and cleaved caspase-3 were detected with Western blotting. Male C57BL/6 mice were randomized into sham operation, I/R, I/R+colchicine, and I/R+colchicine+dorsomorphin (DSMP) groups. After the treatments, myocardial expressions of p-AMPK/AMPK, 8-OHdG, cleaved caspase-3, mitochondrial BAX (Mito-BAX), and cytoplasmic cytochrome C (Cyt-Cyto C) were examined and cardiac functions, infarct area, ATP content, and serum levels of lactic dehydrogenase (LDH) and cardiac troponin T (cTnT) levels were assessed. In H9C2 cells, H/R exposure significantly reduced AMPK phosphorylation and expressions of NRF2, SOD2, and Bcl-2, lowered cell viability, and up-regulated the expressions of NOX4, BAX, and cleaved caspase-3 (P < 0.05), and these changes were obviously alleviated by colchicine treatment (P < 0.05). In the mouse models, myocardial I/R injury significantly reduced myocardial AMPK phosphorylation level, ATP content, and expressions of NRF2, SOD2 and Bcl-2, caused cardiac function impairment, enhanced NOX4, Mito-BAX, Cyt-Cyto C, BAX, 8-OHdG, and cleaved caspase-3 expressions, and increased infarct area and serum LDH and cTnT levels (P < 0.05). Colchicine treatment significantly reversed the damaging effects of I/R (P < 0.05), but its protective effects was obviously antagonized by DSMP (P < 0.05). Colchicine alleviates myocardial I/R injury and protects cardiac function in mice by reducing myocardial oxidative stress and apoptosis via activating AMPK.

Potential protective effects of L-carnitine against myocardial ischemia/reperfusion injury in a rat model.

Myocardial ischemia/reperfusion (I/R) injury is a growing concern for global public health. This study seeks to explore the potential protective effects of L-carnitine (LC) against heart ischemia-reperfusion injury in rats. To induce I/R injury, the rat hearts underwent a 30-min ligation of the left anterior descending coronary artery, followed by 24h of reperfusion. We evaluated cardiac function through electrocardiography and heart rate variability (HRV) and conducted pathological examinations of myocardial structure. Additionally, the study investigated the influence of LC on myocardial apoptosis, inflammation, and oxidative stress in the context of I/R injury. The results show that pretreatment with LC led to improvements in the observed alterations in ECG waveforms and HRV parameters in the nontreated ischemic reperfusion model group, althoughmost of these changes did not reach statistical significance. Similarly, although without a significant difference, LC reduced the levels of proinflammatory cytokines when compared to the values in the nontreated ischemic rat group. Furthermore, LC restored the reduced expressions of SOD1, SOD2, and SOD3. Additionally, LC significantly reduced the elevated Bax expressions and showed a nonsignificant increase in Bcl-2 expression, resulting in a favorable adjustment of the Bcl-2/Bax ratio. We also observed a significant enhancement in the histological appearance of cardiac muscles, a substantial reduction in myocardial fibrosis, and suppressed CD3 + cell proliferation in the ischemic myocardium. This small-scale, experimental, in vivo study indicates that LC was associated with enhancements in the pathological findings in the ischemic myocardium in the context of ischemia/reperfusion injury in this rat model. Although statistical significance was not achieved, LC exhibits potential and beneficial protective effects against I/R injury. It does so by modulating the expression of antioxidative and antiapoptotic genes, inhibiting the inflammatory response, and enhancing autonomic balance, particularly by increasing vagal tone in the heart. Further studies are necessary to confirm and elaborate on these findings.

ATP5me alleviates high glucose-induced myocardial cell injury

BackgroundGestational diabetes mellitus (GDM) is associated with adverse myocardial remodeling and impaired cardiac function of fetus. Nevertheless, specific molecular mechanisms underlying type 1 GDM-induced fetal myocardial injury remain unknown. Therefore, this study proposes to identify possible molecular mechanisms using RNA-seq. MethodsA rat type 1 GDM model was developed using streptozotocin (STZ) (25 and 50 mg/kg), and weight and glucose tolerance of maternal and offspring were evaluated. Changes in markers of myocardial injury and oxidative stress identified by ELISA and biochemical kits in offspring hearts. Identification of differentially expressed mRNAs (DE-mRNAs) associated with myocardial injury in type 1 GDM offspring using RNA-seq. Proliferation, apoptosis, and oxidative stress were assessed in high glucose-induced H9C2 cells after exogenously modulating ATP Synthase Membrane Subunit E (ATP5me). ResultsMaternal weight, glucose and glucose tolerance, and fetal weight and heart weight were reduced in the type 1 GDM model, especially in 50 mg/kg STZ-induced. Increased of creatine kinase-MB (CK-MB), cardiac troponin T (cTnT), hypersensitive C-reactive protein (hs-CRP), reactive oxygen species (ROS) and malondialdehyde (MDA) and decreased of superoxide dismutase (SOD) were observed in type 1 GDM offspring hearts. type 1 GDM offspring hearts exhibited disorganized cardiomyocytes with enlarged gaps, broken myocardial fibers, erythrocyte accumulation and inflammatory infiltration. RNA-seq identified 462 DE-mRNAs in type 1 GDM offspring hearts, which mainly regulate immunity, redox reactions, and cellular communication. Atp5me was under-expressed in type 1 GDM offspring hearts, and high glucose decreased Atp5me expression in H9C2 cells. Overexpressing Atp5me alleviated high glucose-induced decrease in proliferation, mitochondrial membrane potential, BCL2 and SOD, and increase in apoptosis, MDA, ROS, c-Caspase-3, and BAX in H9C2 cells. ConclusionThis study first demonstrated that ATP5me attenuated type 1 GDM-induced fetal myocardial injury. This provides a possible molecular mechanism for the treatment of type 1 GDM-induced fetal myocardial injury.

Curcumin alleviates myocardial inflammation, apoptosis, and oxidative stress induced by acute pulmonary embolism by regulating microRNA-145-5P/insulin receptor substrate 1 axis.

The treatment of patients with acute pulmonary embolism (APE) is extremely challenging due to the complex clinical presentation and prognosis of APE related to the patient's hemodynamic status and insufficient arterial blood flow and right ventricular overload. Protective efficacy against cardiovascular diseases of curcumin, a common natural polyphenolic compound, which has antithrombotic properties and reduces platelet accumulation in the circulation by inhibiting thromboxane synthesis has been demonstrated. However, the direct effect of curcumin on APE has rarely been studied. Therefore, the present study aimed to investigate the therapeutic potential of curcumin in APE and associated myocardial injury to provide new insights into curcumin as a promising competitive new target for the treatment of APE. A suspension of 12 mg/kg microspheres was injected intravenously into rats. An APE rat model was built. Before modeling, intragastric 100 mg/kg curcumin was given, and/or lentiviral plasmid vector targeting microRNA-145-5p or insulin receptor substrate 1 (IRS1) was injected. Pulmonary artery pressure was measured to assess right ventricular systolic pressure (RVSP). Hematoxylin and eosin (H&E) staining was performed on liver tissues and myocardial tissues of APE rats. TUNEL (terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling) staining and immunohistochemical (IHC) staining were conducted to measure apoptosis and CyPA-CD147 expression in the myocardium, respectively. Inflammatory indices interleukin-1beta (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were measured by ELISA in cardiac tissues. RT-qPCR and Western blot were performed to determine the expression levels of related genes. In addition, by dual luciferase reporter assay and RIP assay, the relationship between microRNA-145-5p and insulin receptor substrate 1 (IRS1) was confirmed. In results: curcumin improved APE-induced myocardial injury, reduced myocardial tissue edema, and thrombus volume. It attenuated APE-induced myocardial inflammation and apoptosis, as well as reduced lung injury and pulmonary artery pressure. Curcumin promoted microRNA-145-5p expression in APE rat myocardium. MicroRNA-145-5p overexpression protected against APE-induced myocardial injury, and microRNA-145-5p silencing abolished the beneficial effects of curcumin in APE-induced myocardial injury. IRS1 was targeted by microRNA-145-5p. IRS1 silencing attenuated APE-induced myocardial injury, and enhanced therapeutic effect of curcumin on myocardial injury in APE rats. In conclusion, curcumin alleviates myocardial inflammation, apoptosis, and oxidative stress induced by APE by regulating microRNA-145-5p/IRS1 axis.

CARD9 regulates myocardial inflammation, oxidative stress, and vascular dysfunction in hypertensive rats by activating MAPK/p38 pathway in combination with NOD2

CARD9 regulates myocardial inflammation, oxidative stress, and vascular dysfunction in hypertensive rats by activating MAPK/p38 pathway in combination with NOD2

Taohong siwu decoction suppresses oxidative stress-induced myocardial apoptosis post-myocardial infarction by inhibiting PTEN pathway

BackgroundMyocardial infarction (MI) is an important factor inducing mortality globally. Apoptosis and oxidative stress have been identified as major drivers for MI development. Anti-apoptosis therapies exhibit promising effects in protecting against MI. Typically, Taohong Siwu Decoction (THSWD) exerts cardioprotective properties. However, whether THSWD suppresses oxidative stress-induced myocardial apoptosis after MI and the associated mechanisms remain unclear. PurposeThe present work focused on examining the protective effects of THSWD on oxidative stress-induced myocardial apoptosis after MI and its possible mechanisms. MethodsThe MI mouse model was established via left anterior descending coronary artery (LAD) ligation. Thereafter, echocardiography and histopathology were performed to examine the cardioprotective effects of THSWD. Meanwhile, the protective potential of THSWD against myocardial apoptosis and oxidative stress, as well as modulation of phosphatase and tensin homolog (PTEN) pathway in MI were investigated through TUNEL staining, ROS analysis, immunohistochemistry (IHC), Western blot (WB) and oxidative stress-related biochemical enzyme assay, respectively. Further, the apoptosis of neonatal cardiomyocytes (NCMs) and H9C2 cells was induced by TBHP in vitro. Thereafter, the impacts of THSWD on the TBHP-induced H9C2 and NCMs were detected by Hoechst33342/PI fluorescent staining, WB, ROS analysis, and oxidative stress-related biochemical enzyme assay. In addition, PTEN was overexpressed using transfection viruses in vivo and in vitro for further investigation. ResultsTHSWD might inhibit PTEN and promote the PI3K/AKT pathway in MI mice to prevent myocardial apoptosis. In vitro, THSWD prevented the TBHP-induced apoptosis of NCMs and H9C2 cells. This was achieved by blocking PTEN activity and regulating PI3K/AKT pathway. Moreover, PTEN overexpression significantly enhanced the TBHP-induced H9C2 apoptosis and oxidative stress-induced myocardial apoptosis after MI, and partially blocked the protection of THSWD against myocardial apoptosis and modulating PI3K/AKT pathway in vitro and in vivo. ConclusionTHSWD suppressed oxidative stress-induced myocardial apoptosis in vitro and in vivo by inhibiting PTEN pathway.

Nrf2 prevents diabetic cardiomyopathy via antioxidant effect and normalization of glucose and lipid metabolism in the heart.

Metabolic disorders and oxidative stress are the main causes of diabetic cardiomyopathy. Activation of nuclear factor erythroid 2-related factor 2 (Nrf2) exerts a powerful antioxidant effect and prevents the progression of diabetic cardiomyopathy. However, the mechanism of its cardiac protection and direct action on cardiomyocytes are not well understood. Here, we investigated in a cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) the direct effect of Nrf2 on cardiomyocytes in DCM and its mechanism. In this study, cardiomyocyte-restricted Nrf2 transgenic mice (Nrf2-TG) were used to directly observe whether cardiomyocyte-specific overexpression of Nrf2 can prevent diabetic cardiomyopathy and correct glucose and lipid metabolism disorders in the heart. Compared to wild-type mice, Nrf2-TG mice showed resistance to diabetic cardiomyopathy in a streptozotocin-induced type 1 diabetes mouse model. This was primarily manifested as improved echocardiography results as well as reduced myocardial fibrosis, cardiac inflammation, and oxidative stress. These results showed that Nrf2 can directly act on cardiomyocytes to exert a cardioprotective role. Mechanistically, the cardioprotective effects of Nrf2 depend on its antioxidation activity, partially through improving glucose and lipid metabolism by directly targeting lipid metabolic pathway of AMPK/Sirt1/PGC-1α activation via upstream genes of sestrin2 and LKB1, and indirectly enabling AKT/GSK-3β/HK-Ⅱ activity via AMPK mediated p70S6K inhibition.

FGF12 restrains mitochondria-dependent ferroptosis in doxorubicin-induced cardiomyocytes through the activation of FGFR1/AMPK/NRF2 signaling.

Fibroblast growth factor-12 (FGF12) has been reported to play important role in regulating heart diseases. We aimed to explore the role of FGF12 in doxorubicin (DOX)-induced myocardial injury. DOX-induced mice and DOX-induced HL-1 cells were used as the myocardial injury in vivo and in vitro. Then, FGF12, Anp, Bnp, and Myh7 expression was detected. The pathological injury in myocardium tissue was observed by H&E staining. The levels of markers related to myocardial damage and oxidative stress were assessed. Then, immunohistochemistry and immunofluorescence staining were used to detect FGF12 and 4-HNE expression. Ferroptosis were detected by Prussian blue staining and western blot. The FGFR1/AMPK/NRF2 signaling was measured by western blot. FGF12 expression was downregulated in DOX-induced mice myocardium tissues. FGF12 overexpression alleviated DOX-induced myocardial tissue pathological injury and reduced Anp, Bnp, and Myh7 expression. Additionally, the levels of CK-MB, LDH and cTnT in serum were decreased after FGF12 upregulation in DOX-induced mice. Moreover, FGF12 overexpression reduced the levels of ROS, MDA, and 4-HNE but increased SOD and GSH-Px activities. Meanwhile, FGF12 led to less deposition of iron ion, decreased ACSL4, PTGS2 and increased GPX4, FTH1 expression. Additionally, FGF12 activated the expressions of FGFR1, p-AMPK, and NRF2. Moreover, FGFR1 silencing reversed the protective effects of FGF12 overexpression on cell viability, oxidative stress, ferroptosis, and FGFR1/AMPK/NRF2 pathway. To sum up, FGF12 inhibited mitochondria-dependent ferroptosis in cardiomyocytes induced by DOX through activation of FGFR1/AMPK/NRF2 signaling. These findings clarify a new mechanism of DOX-induced cardiac injury and provide a promising target to limit the disease development.

Myocardial sodium-glucose cotransporter 2 expression and cardiac remodelling in patients with severe aortic stenosis: The BIO-AS study.

Cardiac remodelling plays a major role in the prognosis of patients with aortic stenosis (AS) and could impact the benefits of aortic valve replacement. Our study aimed to evaluate the expression of sodium-glucose cotransporter 2 (SGLT2) gene and protein in patients with severe AS stratified in high gradient (HG) and low flow-low gradient (LF-LG) AS and its association with cardiac functional impairments. Gene expression and protein levels of main biomarkers of cardiac fibrosis (galectin-3, sST2, serpin-4, procollagen type I amino-terminal peptide, procollagen type I carboxy-terminal propeptide, collagen, transforming growth factor [TGF]-β), inflammation (growth differentiation factor-15, interleukin-6, nuclear factor-κB [NF-κB]), oxidative stress (superoxide dismutase 1 [SOD1] and 2 [SOD2]), and cardiac metabolism (sodium-hydrogen exchanger, peroxisome proliferator-activated receptor [PPAR]-α, PPAR-γ, glucose transporter 1 [GLUT1] and 4 [GLUT4]) were evaluated in blood samples and heart biopsies of 45 patients with AS. Our study showed SGLT2 gene and protein hyper-expression in patients with LF-LG AS, compared to controls and HG AS (p < 0.05). These differences remained significant even after adjusting for age, gender, body mass index, history of diabetes mellitus, arterial hypertension, and coronary artery disease. SGLT2 gene expression was positively correlated with: (i) TGF-β (r = 0.72, p < 0.001) and collagen (r = 0.73, p < 0.001) as markers of fibrosis; (ii) NF-κB (r = 0.36, p < 0.01) and myocardial interleukin-6 (r = 0.68, p < 0.001) as markers of inflammation: (iii) SOD2 (r = -0.38, p < 0.006) as a marker of oxidative stress; (iv) GLUT4 (r = 0.33, p < 0.02) and PPAR-α (r = 0.36, p < 0.01) as markers of cardiac metabolism. In patients with LF-LG AS, SGLT2 gene and protein were hyper-expressed in cardiomyocytes and associated with myocardial fibrosis, inflammation, and oxidative stress.

Mitochondria-derived methylmalonic acid aggravates ischemia–reperfusion injury by activating reactive oxygen species-dependent ferroptosis

Ferroptosis is a regulatory cell death process pivotal in myocardial ischemia–reperfusion (I/R) injury. However, the precise mechanism underlying myocardial ferroptosis remains less known. In this study, we investigated the pathophysiological mechanisms of methylmalonic acid (MMA) associated with ferroptosis activation in cardiomyocytes after I/R. We found an increase level of MMA in patients with acute myocardial injury after reperfusion and AC16 cells under hypoxia/reoxygenation (H/R) condition. MMA treatment was found to be associated with excessive oxidative stress in cardiomyocytes, leading to ferroptosis-related myocardial injury. In mice with I/R injury, MMA treatment aggravated myocardial oxidative stress and ferroptosis, which amplified the myocardial infarct size and cardiac dysfunction. Mechanistically, MMA promoted NOX2/4 expression to increase reactive oxygen species (ROS) production in cardiomyocytes, aggravating myocardial injury. Notably, the increased ROS further activated ferroptosis by inhibiting solute carrier family 7 member 11 (SLC7A11) and glutathione peroxidase 4 (GPX4) expression. In addition, MMA decreased the ectopic nuclear distribution of nuclear factor E2-related factor 2 (NRF2) by increasing the interaction between NRF2 and kelch-like ECH-associated protein 1 (KEAP1). This impeded the activation of GPX4/SLC7A11, downstream of NRF2, activating ferroptosis and aggravating myocardial cell injury. Collectively, our study indicates that MMA activates oxidative stress and ROS generation, which induces ferroptosis to exacerbate cardiomyocyte injury in an I/R model. These findings may provide a new perspective for the clinical treatment of I/R injury and warrant further investigation.

Importance of Per2 in cardiac mitochondrial protection during stress

During myocardial injury, inflammatory mediators and oxidative stress significantly increase to impair cardiac mitochondria. Emerging evidence has highlighted interplays between circadian protein—period 2 (Per2) and mitochondrial metabolism. However, besides circadian rhythm regulation, the direct role of Per2 in mitochondrial performance particularly following acute stress, remains unknown. In this study, we aim to determine the importance of Per2 protein’s regulatory role in mitochondrial function following exposure to inflammatory cytokine TNFα and oxidative stressor H2O2 in human cardiomyocytes. Global warm ischemia (37 °C) significantly impaired complex I activity with concurrently reduced mitochondrial Per2 in adult mouse hearts. TNFα or H2O2 decreased Per2 protein levels and damaged mitochondrial respiratory function in adult mouse cardiomyocytes. Next, mitochondrial membrane potential (Δψ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta \\psi$$\\end{document}M) using JC-1 fluorescence probe and mitochondrial respiration capacity via Seahorse Cell Mito Stress Test were then detected in Per2 or control siRNA transfected AC16 Human Cardiomyocytes (HCM) that were subjected to 2 h-treatment of TNFα (100 ng/ml) or H2O2 (100 μM). After 4 h-treatment, cell death was also measured using Annexin V and propidium iodide apoptosis kit through flow cytometry. We found that knockdown of Per2 enhanced TNFα-induced cell death and TNFα- or H2O2-disrupted Δψ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Delta \\psi$$\\end{document}M, as well as TNFα- or H2O2-impaired mitochondrial respiration function. In conclusion, Per2 knockdown increases likelihood of cell death and mitochondrial dysfunction in human cardiomyocytes exposed to either TNFα or H2O2, supporting the protective role of Per2 in HCM during stress with a focus on mitochondrial function.

Atractylenolide II ameliorates myocardial fibrosis and oxidative stress in spontaneous hypertension rats.

Hypertension is a well-recognized risk factor for cardiovascular, which is also a critical factor in causing myocardial fibrosis (MF). The study aimed to explore the effect of Atractylenolide II (ATL-II) on MF and oxidative stress in spontaneous hypertension rats (SHR). The body weight of rats after injection of ATL-II was quantitatively analyzed. The left ventricular function of SHR was evaluated by Echocardiographic. HE staining, Masson trichrome staining, left ventricular mass index (LVMI) and immunofluorescence was applied to investigate the effects of ATL-II on MF. RT qPCR was used to detect the Collagen I, α-SMA, Fibronectin, and Vimentin mRNA expression levels in myocardial slices. The effect ATL-II on cardiomyocyte apoptosis was detected by TUNEL staining and western blot. An immunohistochemistry assay was conducted to detect α-SMA protein and TGF-β1 protein. The contents of H2O2, GSH-PX, SOD, and MDA were measured by colorimetry. ATL-II could dose-dependently improve the BW of SHRs (P< 0.05) and enhance myocardial function. Moreover, ATL-II effectively reduced cardiomyocyte apoptosis in SHRs. Alternatively, ATL-II could inhibit the Collagen I, α-SMA, Fibronectin, and Vimentin mRNA and protein expression levels in SHRs. ATL-II could ameliorate oxidative stress by improving the activities of SOD and GSH-PX and lowering the contents of H2O2 and MDA in ATL-II-treated SHRs, which reach about 80%. ATL-II could exert an inhibiting effect on MF and oxidative stress in SHRs. Hence, ATL-II may hold promise for the treatment of MF and oxidative stress in Spontaneous Hypertension.