Suppression of Oxidative Stress and Apoptosis in Electrically Stimulated Neonatal Rat Cardiomyocytes by Resveratrol and Underlying Mechanisms

Antioxidant Cardioprotection against Reperfusion Injury: Potential Therapeutic Roles of Resveratrol and Quercetin

Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Therefore, it is worthwhile to consider multitarget antioxidant therapies targeting multifactorial AMI. Indeed, this clinical setting involves injurious effects derived from oxygen deprivation, intracellular pH changes and increased concentration of cytosolic Ca²⁺ and reactive oxygen species, among others. Thus, we will review a brief overview of the pathological cascades involved in ischemia-reperfusion injury and the potential therapeutic effects based on preclinical studies involving a combination of antioxidants, with particular reference to resveratrol and quercetin, which could contribute to cardioprotection against ischemia-reperfusion injury in myocardial tissue. We will also highlight the upcoming perspectives of these antioxidants for designing future studies.

Resveratrol protects against myocardial ischemia-reperfusion injury via attenuating ferroptosis

Resveratrol (Res) is a polyphenol with a variety of biological activities. However, whether Res can prevent myocardial ischemia-reperfusion (I/R) injury is not yet known. This study aimed to investigate the protective effect of Res on myocardial I/R injury and to explore its potential mechanism. H9c2 cells were used for the in vitro experiments and oxygen-glucose deprivation/reoxygenation (OGD/R) model was established. Rats were ligated and perfused by the left anterior descending branch with or without Res (50 mg/kg·bw) for 14 days.The higher level of oxidative stress and Fe²⁺ content was observed in OGD/R-induced H9c2 cells than that of normal cells. OGD/R-induced H9c2 cells showed increased ferroptosis, mainly by reducing the expression of glutathione peroxidase 4 (GPX4) and ferritin heavy chain 1 (FTH1), but enhancing the expression of transferrin receptor 1 (TfR1). Both in vivo and in vitro experiments indicated that Res reduced the level of oxidative stress and Fe2 + content. In addition, Res inhibited ferroptosis, decreased TfR1 expression, and increased the expressions of FTH1 and GPX4 in OGD/R-induced H9c2 cells and I/R rats. Moreover, we found that Res inhibited ferroptosis by the regulation of ubiquity specific peptidase 19 (USP19)-Beclin1 autophagy. Res protects against myocardial I/R injury via reducing oxidative stress and attenuating ferroptosis. Res could be a potential agent to the prevention of myocardial I/R injury.

Resveratrol pretreatment mitigates LPS-induced acute lung injury by regulating conventional dendritic cells' maturation and function

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a severe syndrome lacking efficient therapy and resulting in high morbidity and mortality. Although resveratrol (RES), a natural phytoalexin, has been reported to protect the ALI by suppressing the inflammatory response, the detailed mechanism of how RES affected the immune system is poorly studied. Pulmonary conventional dendritic cells (cDCs) are critically involved in the pathogenesis of inflammatory lung diseases including ALI. In this study, we aimed to investigate the protective role of RES via pulmonary cDCs in lipopolysaccharide (LPS)-induced ALI mice. Murine ALI model was established by intratracheally challenging with 5 mg/kg LPS. We found that RES pretreatment could mitigate LPS-induced ALI. Additionally, proinflammatory-skewed cytokines decreased whereas anti-inflammatory-related cytokines increased in bronchoalveolar lavage fluid by RES pretreatment. Mechanistically, RES regulated pulmonary cDCs’ maturation and function, exhibiting lower level of CD80, CD86, major histocompatibility complex (MHC) II expression, and IL-10 secretion in ALI mice. Furthermore, RES modulated the balance between proinflammation and anti-inflammation of cDCs. Moreover, in vitro RES pretreatment regulated the maturation and function of bone marrow derived dendritic cells (BMDCs). Finally, the adoptive transfer of RES-pretreated BMDCs enhanced recovery of ALI. Thus, these data might further extend our understanding of a protective role of RES in regulating pulmonary cDCs against ALI.

Zn2+ and mPTP mediate resveratrol-induced myocardial protection from endoplasmic reticulum stress

Resveratrol displays cardioprotective activity; however, its mechanism of action remains unclear. In the current study, resveratrol-induced myocardial protection from endoplasmic reticulum stress (ERS) was investigated, focusing on the roles of Zn2+ and the mitochondrial permeability transition pore (mPTP). We found, using the MTT/LDH kit, that 2-DG-induced ERS significantly decreased H9c2 cell viability. Resveratrol markedly inhibited the expression of endoplasmic reticulum chaperone GRP 78/94 and ERS-related apoptosis proteins CHOP, Caspase12, and JNK induced by 2-DG. The zinc ion chelator TPEN, and ERK/GSK-3β inhibitors PD98059 and SB216763 and their siRNAs blocked resveratrol function. The AKT inhibitor LY294002 and siRNA did not alter the action of resveratrol. In addition, resveratrol significantly increased the phosphorylation of ERK and GSK-3β. Resveratrol prevented 2-DG-induced mPTP opening and increased intracellular Zn2+ concentration indicated by TMRE and Newport Green DCF fluorescence intensity, which were further abrogated by ERK/GSK-3β inhibitors and siRNAs. Our data suggested that resveratrol protected cardiac cells from ERS by mobilizing intracellular Zn2+ and preventing mPTP opening through the ERK/GSK-3β but not PI3K/AKT signaling pathway.

Arenobufagin Promoted Oxidative Stress-Associated Mitochondrial Pathway Apoptosis in A549 Non-Small-Cell Lung Cancer Cell Line

Arenobufagin (ARE) has demonstrated potent anticancer activity in various types of tumor, but the role and mechanism of ARE for lung cancer remain unclear. Oxidative stress exists under normal conditions and is an inevitable state in the body. A variety of noxious stimuli can break the equilibrium state of oxidative stress and promote apoptosis. Here, we used a CCK-8 assay to examine cell viability. We determined oxidative stress damage by measuring levels of intracellular ROS and levels of GSH, SOD, and MDA. Annexin V-FITC/PI double staining assay, as well as the Hoechst 33258 staining, was used to detect ARE-induced apoptosis in A549 cell. Evaluation of the expression level of the specified molecule was indicated by Western blot and qRT-PCR. Loss of function experiment was carried out using NAC pretreatment. The experimental results show that ARE significantly declines in the viability of A549 cells and increases the apoptosis rate of A549 cells. As reflected in cell morphology, the A549 cells showed features of shrinkage and had incompletely packed membranes; the same phenomenon is manifested in Hoechst 33258 staining. Following ARE treatment, the ROS level in A549 cells was rising in a concentration-dependent manner, and so were MDA and GSH levels, while the SOD level was decreasing. Moreover, we found that ARE can decrease mitochondrial membrane potential (MMP), and a cascade of apoptotic processes can be triggered by decreased MMP. Importantly, we found significant changes in protein expression levels and mRNA levels of apoptosis-related proteins. Furthermore, when we used NAC to restrain oxidative stress, the expression levels of apoptosis-related proteins have also changed accordingly. Our data demonstrate that apoptosis in the non-small-cell lung cancer (NSCLC) cell line A549 is caused by oxidative stress due to ARE. Our research also shows that ARE may have the potential to become a targeted therapeutic for the treatment of NSCLC in the future.

Effects and mechanisms of pyrethroids on male reproductive system

Synthetic pyrethroids are used as insecticides in agriculture and a variety of household applications worldwide. Pyrethroids are widely distributed in all environmental compartments and the general populations are exposed to pyrethroids through various routes. Pyrethroids have been identified as endocrine-disrupting chemicals (EDCs) which are responsible for the male reproductive impairments. The data confirm pyrethroids cause male reproductive damages. The insecticides exert the toxic effects on male reproductive system through various complex mechanisms including antagonizing androgen receptor (AR), inhibiting steroid synthesis, affecting the hypothalamic-pituitary-gonadal (HPG) axis, acting as estrogen receptor (ER) modulators and inducing oxidative stress. The mechanisms of male reproductive toxicity of pyrethroids involve multiple targets and pathways. The review will provide further insight into pyrethroid-induced male reproductive toxicity and mechanisms, which is crucial to preserve male reproductive health.

Oxidative Stress in Radiation-Induced Cardiotoxicity

There is a distinct increase in the risk of heart disease in people exposed to ionizing radiation (IR). Radiation-induced heart disease (RIHD) is one of the adverse side effects when people are exposed to ionizing radiation. IR may come from various forms, such as diagnostic imaging, radiotherapy for cancer treatment, nuclear disasters, and accidents. However, RIHD was mainly observed after radiotherapy for chest malignant tumors, especially left breast cancer. Radiation therapy (RT) has become one of the main ways to treat all kinds of cancer, which is used to reduce the recurrence of cancer and improve the survival rate of patients. The potential cause of radiation-induced cardiotoxicity is unclear, but it may be relevant to oxidative stress. Oxidative stress, an accumulation of reactive oxygen species (ROS), disrupts intracellular homeostasis through chemical modification and damages proteins, lipids, and DNA; therefore, it results in a series of related pathophysiological changes. The purpose of this review was to summarise the studies of oxidative stress in radiotherapy-induced cardiotoxicity and provide prevention and treatment methods to reduce cardiac damage.

Preventive Role of Resveratrol Against Inflammatory Cytokines and Related Diseases

BACKGROUND

Immunity is the ultimate barrier between foreign stimuli and a host cell. Unwanted immune responses can threaten the host cells and may eventually damage a vital organ. Overproduction of inflammatory cytokines may also lead to autoimmune diseases. Inflammatory cells and pro-inflammatory cytokines can eventually progress to renal, cardiac, brain, hepatic, pancreatic and ocular inflammation that can result in severe damage in the long run. Evidence also suggests that inflammation may lead to atherosclerosis, Alzheimer's, hypertension, stroke, cysts and cancers.

METHODS

This study was designed to correlate the possible molecular mechanisms for inflammatory diseases and prevent biochemical changes owing to inflammatory cytokines by using Resveratrol. Therefore, we searched and accumulated very recent literature on inflammatory disorders and Resveratrol. We scoured PubMed, Scopus, Science Direct, PLoS One and Google Scholar to gather papers and related information.

RESULTS

Reports show that inflammatory diseases are very complex, as multiple cascade systems are involved; therefore, they are quite difficult to cure. However, our literature search also correlates some possible molecular interactions by which inflammation can be prevented. We noticed that Resveratrol is a potent lead component and has multiple activities against harmful inflammatory cytokines and related microRNA. Our study also suggests that the anti-inflammatory properties of Resveratrol have been highly studied on animal models, cell lines and human subjects and proven to be very effective in reducing inflammatory cell production and pro-inflammatory cytokine accumulation. Our tables and figures also demonstrate recent findings and possible preventive activities to minimize inflammatory diseases.

CONCLUSION

This study would outline the role of harmful inflammatory cytokines as well as how they accelerate pathophysiology and progress to an inflammatory disorder. Therefore, this study might show a potential therapeutic value of using Resveratrol by health professionals in preventing inflammatory disorders.

Melatonin Protects Rabbit Somatic Cell Nuclear Transfer (SCNT) Embryos from Electrofusion Damage

The study’s objectives were to examine the effects of electrofusion on rabbit somatic cell nuclear transfer (SCNT) embryos, and to test melatonin as a protective agent against electrofusion damage to SCNT embryos. The levels of reactive oxygen species (ROS), the epigenetic state (H3K9me3), and the content of endoplasmic reticulum (ER) stress-associated transcripts (IRE-1 and CHOP) were measured. Melatonin was added during the preimplantation development period. The total blastocyst cell numbers were counted, and the fragmentation rate and apoptotic index were determined and used to assess embryonic development. Electrofusion increased (1) ROS levels at the 1-, 2-, 4-, and 8-cell stages; (2) H3K9me3 levels at the 2-, 4-, and 8-cell stage; and (3) the expression of IRE-1 and CHOP at the 8-cell, 16-cell, morula, and blastocyst stages. The treatment of SCNT embryos with melatonin significantly reduced the level of ROS and H3K9me3, and the expression levels of IRE-1 and CHOP. This treatment also significantly reduced the fragmentation rate and apoptotic index of blastocysts and increased their total cell number. In conclusion, the electrofusion of rabbit SCNT embryos induced oxidative stress, disturbed the epigenetic state, and caused ER stress, while melatonin reduced this damage. Our findings are of signal importance for improving the efficiency of SCNT and for optimizing the application of electrical stimulation in other biomedical areas.

Diabetic retinopathy: Focus on NADPH oxidase and its potential as therapeutic target

Diabetic retinopathy is a common complication of diabetes that affects the retina due to a sustained high blood sugar level. Recent studies have demonstrated that high glucose-driven oxidative stress plays an important role in the microvascular complications of retina in diabetes. Oxidative stress occurs due to the excess of reactive oxygen species, which causes oxidative damage to retina, leading to the leak of tiny blood vessels, or acts as signaling molecules to trigger neovascularization, resulting in new fragile vessels. NADPH oxidase (NOX) is a key enzymatic source of reactive oxygen species in the retina, and it is involved in the early as well as the advanced stage of diabetic retinopathy. To date, at least 7 NOX isoforms, including NOX1 to NOX5, dual oxidase1 and dual oxidase 2, have been identified. It has been shown that NOX isoforms exert different roles in the pathogenesis of diabetic retinopathy. Intervention of NOX by its inhibitors or modulators shows beneficial effect on improving the retinal functions in the models of diabetic retinopathy in vivo or in vitro. Thereby, NOX might be a potential target for the therapy of diabetic retinopathy. The present review focuses on the role of NOX, particularly the NOX isoforms, in promoting the development of diabetic retinopathy. In addition, NOX isoforms as potential targets for therapy of diabetic retinopathy are also discussed.

Resveratrol alleviates hypoxia/reoxygenation injury‑induced mitochondrial oxidative stress in cardiomyocytes

Resveratrol (RES) is a naturally occurring antioxidant compound found in red wine. Although it has been demonstrated to have a cardioprotective effect, the mechanism underlying this effect remains to be fully elucidated. The aim of the present study was to determine whether RES exerts a protective effect against mitochondrial oxidative stress and apoptosis in neonatal rat cardiomyocytes (NRCMs) induced by hypoxia/reoxygenation (H/R) injury. Primary cultured NRCMs were used as a model system and were divided into four experimental groups: Control, H/R, H/R + DMSO (H/R with 0.2% DMSO) and H/R + RES (H/R with 100 µM RES) groups. Mitochondrial oxidative stress was determined by measuring the alteration in the mitochondrial membrane potential (ΔΨm) of NRCMs, the release of lactate dehydrogenase (LDH) and the ratio of B-cell lymphoma 2 (Bcl-2)/Bcl-2-associated X protein (Bax) from NRCMs. Cell apoptosis was assessed by measuring cell apoptotic rates and the activity of caspase 3. In the H/R+RES group, RES significantly alleviated structural impairment, including disordered α-actin and F-actin, in the NRCMs induced by H/R injury. RES attenuated H/R injury-induced mitochondria oxidative stress. RES also attenuated H/R injury-induced cell apoptosis; it decreased the NRCM apoptotic rate from 84.25±7.41% (H/R) to 46.39±5.43% (H/R+RES) (P<0.05, n=4), rescued the decrease in the Bcl2/Bax ratio induced by H/R from 0.53±0.08-fold (H/R) to 0.86±0.06-fold (H/R+RES) (P<0.05, n=5) and alleviated the increased activity of caspase 3 induced by H/R from 1.32±0.06-fold to 1.02±0.04-fold (P<0.05, n=5). Furthermore, RES significantly attenuated the increment of LDH release induced by H/R injury in NRCMs from 1.41±0.03-fold (H/R) to 1.02±0.06-fold (H/R+RES) (P<0.01, n=4) and alleviated the depolarization of ΔΨm induced by H/R, shifting the ratio of JC-1 monomer from 62.39±1.82% (H/R) to 35.31±8.63% (H/R+RES) (P<0.05, n=4). RES alleviated the decrease in sirtuin 1 induced by H/R injury from 0.61±0.06-fold (H/R) to 1.01±0.05-fold (H/R+RES) (P<0.05, n=5). In conclusion, the present study is the first, to the best of our knowledge, to demonstrate that RES provides cardioprotection against H/R injury through decreasing mitochondria-mediated oxidative stress injury and structural impairment in NRCMs. These results provide scientific evidence for the clinical application of RES in the treatment of cardiac conditions.

Study of Electrical Stimulation with Different Electric-Field Intensities in the Regulation of the Differentiation of PC12 Cells

The strategy of using electrical stimulation (ES) to promote the neural differentiation and regeneration of injured nerves is proven feasible. Study of the possible molecular mechanisms in relation to this ES promotion effect should be helpful for understanding the phenomenon. In this study, it was identified that the neuronal differentiation of PC12 cells was enhanced when the electric field intensity was in the range of 30-80 mV/mm, and a lower or higher electric-field intensity displayed inferior effects. Under ES, however, levels of intracellular reactive oxygen species (ROS), intracellular Ca²⁺ dynamics, and expression of TREK-1 were measured as being gradually increasing alongside higher electric-field intensity. In trying to understand the relationship between the ES enhancement on differentiation and these variations in cell activities, parallel experiments were conducted by introducing exogeneous H₂O₂ into culture systems at different concentrations. Similarly, the effects of H₂O₂ concentration on the neuronal differentiation of PC12 cells, intracellular ROS and Ca²⁺ levels, and TREK-1 expression were systematically characterized. In comparative studies, it was found in two cases that ES of 50 mV/mm for 2 h/day and H₂O₂ of 5 μM in culture medium shared comparable results for intracellular ROS and Ca²⁺ levels and TREK-1 expression. Higher H₂O₂ concentrations (e.g., 10 and 20 μM) demonstrated adverse effects on cell differentiation and caused DNA damage. A stronger ES (e.g., 100 mV/mm), being associated with a higher intracellular ROS level, also resulted in weaker enhancement of the neuronal differentiation of PC12 cells. These facts suggested that the intracellular ROS generated under ES might be an intermediate signal transducer involved in cascade reactions relative to cell differentiation.

Genetic regulation of longevity and age-associated diseases through the methionine sulfoxide reductase system

Methionine sulfoxide reductase enzymes are a protective system against biological oxidative stress in aerobic organisms. Modifications to this antioxidant system have been shown to impact the lifespan of several model system organisms. In humans, methionine oxidation of critical proteins and deficiencies in the methionine sulfoxide reductase system have been linked to age-related diseases, including cancer and neurodegenerative disease. Substrates for methionine sulfoxide reductases have been reviewed multiple times, and are still an active area of discovery. In contrast, less is known about the genetic regulation of methionine sulfoxide reductases. In this review, we discuss studies on the genetic regulation of the methionine sulfoxide reductase system with relevance to longevity and age-related diseases. A better understanding of genetic regulation for methionine sulfoxide reductases may lead to new therapeutic approaches for age-related diseases in the future.

Protective effects of kenpaullone on cardiomyocytes following H2O2-induced oxidative stress are attributed to inhibition of connexin 43 degradation by SGSM3

A previous study showed that small G protein signaling modulator 3 (SGSM3) was highly correlated with Cx43 in heart functions and that high levels of SGSM3 may induce Cx43 turnover through lysosomal degradation in infarcted rat hearts. Here, we investigated the protective effects of kenpaullone on cardiomyocytes following H₂O₂-induced oxidative stress mediated by the interaction of SGSM3 with Cx43. We found that the gap junction protein Cx43 was significantly down-regulated in an H₂O₂ concentration-dependent manner, whereas expression of SGSM3 was up-regulated upon H₂O₂ exposure in H9c2 cells. The effect of kenpaullone pretreatment on H₂O₂-induced cytotoxicity was evaluated in H9c2 cells. H₂O₂ markedly increased the release of lactate dehydrogenase (LDH), while kenpaullone pretreatment suppressed LDH release in H9c2 cells. Moreover, kenpaullone pretreatment significantly reduced ROS fluorescence intensity and significantly down-regulated the level of apoptosis-activating genes (cleaved caspase-3, cleaved caspase-9 and cytochrome C), autophagy markers (LC3A/B), and the Cx43-interacting partner SGSM3. These results suggest that kenpaullone plays a role in protecting cardiomyocytes from oxidative stress and that the turnover of Cx43 through SGSM3-induced lysosomal degradation underlies the anti-apoptotic effect of kenpaullone.