Reactive oxygen species in cardiovascular disease

A Broad-Spectrum ROS-Eliminating Material for Prevention of Inflammation and Drug-Induced Organ Toxicity

Despite the great potential of numerous antioxidants for pharmacotherapy of diseases associated with inflammation and oxidative stress, many challenges remain for their clinical translation. Herein, a superoxidase dismutase/catalase-mimetic material based on Tempol and phenylboronic acid pinacol ester simultaneously conjugated β-cyclodextrin (abbreviated as TPCD), which is capable of eliminating a broad spectrum of reactive oxygen species (ROS), is reported. TPCD can be easily synthesized by sequentially conjugating two functional moieties onto a β-cyclodextrin scaffold. The thus developed pharmacologically active material may be easily produced into antioxidant and anti-inflammatory nanoparticles, with tunable size. TPCD nanoparticles (TPCD NP) effectively protect macrophages from oxidative stress-induced apoptosis in vitro. Consistently, TPCD NP shows superior efficacies in three murine models of inflammatory diseases, with respect to attenuating inflammatory responses and mitigating oxidative stress. TPCD NP can also protect mice from drug-induced organ toxicity. Besides the passive targeting effect, the broad spectrum ROS-scavenging capability contributes to the therapeutic benefits of TPCD NP. Importantly, in vitro and in vivo preliminary experiments demonstrate the good safety profile of TPCD NP. Consequently, TPCD in its native and nanoparticle forms can be further developed as efficacious and safe therapies for treatment of inflammation and oxidative stress-associated diseases.

Targeted Therapy of Atherosclerosis by a Broad-Spectrum Reactive Oxygen Species Scavenging Nanoparticle with Intrinsic Anti-inflammatory Activity

Atherosclerosis is a leading cause of vascular diseases worldwide. Whereas antioxidative therapy has been considered promising for the treatment of atherosclerosis in view of a critical role of reactive oxygen species (ROS) in the pathogenesis of atherosclerosis, currently available antioxidants showed considerably limited clinical outcomes. Herein, we hypothesize that a broad-spectrum ROS-scavenging nanoparticle can serve as an effective therapy for atherosclerosis, taking advantage of its antioxidative stress activity and targeting effects. As a proof of concept, a broad-spectrum ROS-eliminating material was synthesized by covalently conjugating a superoxide dismutase mimetic agent Tempol and a hydrogen-peroxide-eliminating compound of phenylboronic acid pinacol ester onto a cyclic polysaccharide β-cyclodextrin (abbreviated as TPCD). TPCD could be easily processed into a nanoparticle (TPCD NP). The obtained nanotherapy TPCD NP could be efficiently and rapidly internalized by macrophages and vascular smooth muscle cells (VSMCs). TPCD NPs significantly attenuated ROS-induced inflammation and cell apoptosis in macrophages, by eliminating overproduced intracellular ROS. Also, TPCD NPs effectively inhibited foam cell formation in macrophages and VSMCs by decreasing internalization of oxidized low-density lipoprotein. After intravenous (i.v.) administration, TPCD NPs accumulated in atherosclerotic lesions of apolipoprotein E-deficient (ApoE^-/-) mice by passive targeting through the dysfunctional endothelium and translocation via inflammatory cells. TPCD NPs significantly inhibited the development of atherosclerosis in ApoE^-/- mice after i.v. delivery. More importantly, therapy with TPCD NPs afforded stabilized plaques with less cholesterol crystals, a smaller necrotic core, thicker fibrous cap, and lower macrophages and matrix metalloproteinase-9, compared with those treated with control drugs previously developed for antiatherosclerosis. The therapeutic benefits of TPCD NPs mainly resulted from reduced systemic and local oxidative stress and inflammation as well as decreased inflammatory cell infiltration in atherosclerotic plaques. Preliminary in vivo tests implied that TPCD NPs were safe after long-term treatment via i.v. injection. Consequently, TPCD NPs can be developed as a potential antiatherosclerotic nanotherapy.

Effect of proton pump inhibitors on sympathetic hyperinnervation in infarcted rats: Role of magnesium

The long-term use of proton pump inhibitors (PPIs) has been shown to increase the risk of cardiovascular mortality, however the molecular mechanisms are unknown. Superoxide has been implicated in the regulation of nerve growth factor (NGF), a mediator of sympathetic innervation. The purpose of this study was to determine whether PPIs increase ventricular arrhythmias through magnesium-mediated superoxide production in infarcted rats. Male Wistar rats were randomly assigned to receive vehicle, omeprazole, omeprazole + magnesium sulfate, or famotidine treatment for 4 weeks starting 24 hours after the induction of myocardial infarction by ligating the coronary artery. Increased myocardial superoxide and nitrotyrosine levels were noted post-infarction, in addition to a significant upregulation of NGF expression on mRNA and protein levels. Sympathetic hyperinnervation after infarction was confirmed by measuring myocardial norepinephrine and immunofluorescent analysis. Compared with the vehicle, omeprazole-treated infarcted rats had significantly reduced myocardial magnesium content, increased oxidant production, and increased sympathetic innervation, which in turn increased ventricular arrhythmias. These effects were prevented by the coadministration of magnesium sulfate. In an in vivo study, an omeprazole-induced increase in NGF was associated with a superoxide pathway, which was further confirmed by an ex vivo study showing the attenuation of NGF levels after coadministration of the superoxide scavenger Tiron. Magnesium sulfate did not further attenuate NGF levels compared with omeprazole + Tiron. Our results indicate that the long-term administration of PPIs was associated with reduced tissue magnesium content and increased myocardial superoxide production, which exacerbated ventricular arrhythmias after infarction. Magnesium may be a potential target for PPI-related arrhythmias after infarction.

Protective Effects of Rhodiola Crenulata Extract on Hypoxia-Induced Endothelial Damage via Regulation of AMPK and ERK Pathways

Rhodiola crenulata root extract (RCE) has been shown to possess protective activities against hypoxia both in vitro and in vivo. However, the effects of RCE on response to hypoxia in the endothelium remain unclear. In this study, we aimed to examine the effects of RCE in endothelial cells challenged with hypoxic exposure and to elucidate the underlying mechanisms. Human umbilical vein endothelial cells were pretreated with or without RCE and then exposed to hypoxia (1% O₂) for 24 h. Cell viability, nitric oxide (NO) production, oxidative stress markers, as well as mechanistic readouts were studied. We found that hypoxia-induced cell death, impaired NO production, and oxidative stress. These responses were significantly attenuated by RCE treatment and were associated with the activation of AMP-activated kinase and extracellular signal-regulated kinase 1/2 signaling pathways. In summary, we showed that RCE protected endothelial cells from hypoxic insult and suggested that R. crenulata might be useful for the prevention of hypoxia-associated vascular dysfunction.

MiR-30e Attenuates Isoproterenol-induced Cardiac Fibrosis Through Suppressing Snai1/TGF-β Signaling

Background:

MicroRNAs are a class of small RNA molecules that inhibit protein expression through either degradation of messenger RNA or interference with protein translation. Our previous work suggested an involvement of miR-30e in myocardial fibrosis; however, the exact role of miR-30e in the pathogenesis of cardiac fibrosis and the underlying mechanisms are not known.

Methods:

Male Sprague Dawley rats were treated with isoproterenol (ISO) to induce cardiac remodeling and fibrosis and treated with either miR-30e agomir (AG) or antagomir and respective controls. The expression of miR-30e was evaluated by reverse transcription and quantitative polymerase chain reaction. Myocardial fibrosis was assessed by Masson's trichrome staining, and the level of oxidative stress and the expression of Snai1 and transforming growth factor-beta (TGF-β) were detected using Western blots.

Results:

A significant downregulation of miR-30e was found in the hearts of ISO-treated rats with cardiac fibrosis compared with nontreated controls. In vivo administration of miR-30e AG increased the survival of ISO-treated rats compared with AG-negative control administration, which was associated with reduced oxidative stress. We further identified Snai1 as a novel miR-30e target. Snai1 expression was significantly increased in hearts from ISO-treated rats, which coincided with decreased miR-30e expression and increased TGF-β expression. An miR-30e putative target sequence was identified in the 3′-untranslated region (UTR) Snai1. In a reporter assay, miR-30e greatly suppressed the activity of wild-type 3′-UTR–fused luciferase reporter, but showed no significant effect with the mutated 3′-UTR–fused reporter.

Conclusion:

MiR-30e attenuated ISO-induced cardiac dysfunction and cardiac fibrosis in a rat cardiac remodeling model. Mechanistically, miR-30e suppressed Snai1/TGF-β pathway which was involved in ISO-induced cardiac remodeling.

Galectin-3 down-regulates antioxidant peroxiredoxin-4 in human cardiac fibroblasts: a new pathway to induce cardiac damage

Galectin-3 (Gal-3) is increased in heart failure (HF) and promotes cardiac fibrosis and inflammation. We investigated whether Gal-3 modulates oxidative stress in human cardiac fibroblasts, in experimental animal models and in human aortic stenosis (AS). Using proteomics and immunodetection approaches, we have identified that Gal-3 down-regulated the antioxidant peroxiredoxin-4 (Prx-4) in cardiac fibroblasts. In parallel, Gal-3 increased peroxide, nitrotyrosine, malondialdehyde, and N-carboxymethyl-lysine levels and decreased total antioxidant capacity. Gal-3 decreased prohibitin-2 expression without modifying other mitochondrial proteins. Prx-4 silencing increased oxidative stress markers. In Gal-3-silenced cells and in heart from Gal-3 knockout mice, Prx-4 was increased and oxidative stress markers were decreased. Pharmacological inhibition of Gal-3 with modified citrus pectin restored cardiac Prx-4 as well as prohibitin-2 levels and improved oxidative status in spontaneously hypertensive rats. In serum from 87 patients with AS, Gal-3 negatively correlated with total antioxidant capacity and positively correlated with peroxide. In myocardial biopsies from 26 AS patients, Gal-3 up-regulation paralleled a decrease in Prx-4 and in prohibitin-2. Cardiac Gal-3 inversely correlated with Prx-4 levels in myocardial biopsies. These data suggest that Gal-3 decreased Prx-4 antioxidant system in cardiac fibroblasts, increasing oxidative stress. In pathological models presenting enhanced cardiac Gal-3, the decrease in Prx-4 expression paralleled increased oxidative stress. Gal-3 blockade restored Prx-4 expression and improved oxidative stress status. In AS, circulating levels of Gal-3 could reflect oxidative stress. The alteration of the balance between antioxidant systems and reactive oxygen species production could be a new pathogenic mechanism by which Gal-3 induces cardiac damage in HF.

Nuclear factor E2-related factor 2 deficiency impairs atherosclerotic lesion development but promotes features of plaque instability in hypercholesterolaemic mice

Aims

Oxidative stress and inflammation play an important role in the progression of atherosclerosis. Transcription factor NF-E2-related factor 2 (Nrf2) has antioxidant and anti-inflammatory effects in the vessel wall, but paradoxically, global loss of Nrf2 in apoE deficient mice alleviates atherosclerosis. In this study, we investigated the effect of global Nrf2 deficiency on early and advanced atherogenesis in alternative models of atherosclerosis, LDL receptor deficient mice (LDLR−/−), and LDLR−/− mice expressing apoB-100 only (LDLR−/− ApoB100/100) having a humanized lipoprotein profile.

Methods and results

LDLR−/− mice were fed a high-fat diet (HFD) for 6 or 12 weeks and LDLR−/−ApoB100/100 mice a regular chow diet for 6 or 12 months. Nrf2 deficiency significantly reduced early and more advanced atherosclerosis assessed by lesion size and coverage in the aorta in both models. Nrf2 deficiency in LDLR−/− mice reduced total plasma cholesterol after 6 weeks of HFD and triglycerides in LDLR−/−ApoB100/100 mice on a chow diet. Nrf2 deficiency aggravated aortic plaque maturation in aged LDLR−/−ApoB100/100 mice as it increased plaque calcification. Moreover, ∼36% of Nrf2−/−LDLR−/−ApoB100/100 females developed spontaneous myocardial infarction (MI) or sudden death at 5 to 12 months of age. Interestingly, Nrf2 deficiency increased plaque instability index, enhanced plaque inflammation and calcification, and reduced fibrous cap thickness in brachiocephalic arteries of LDLR−/−ApoB100/100 female mice at age of 12 months.

Conclusions

Absence of Nrf2 reduced atherosclerotic lesion size in both atherosclerosis models, likely via systemic effects on lipid metabolism. However, Nrf2 deficiency in aged LDLR−/−ApoB100/100 mice led to an enhanced atherosclerotic plaque instability likely via increased plaque inflammation and oxidative stress, which possibly predisposed to MI and sudden death.

Homoeriodictyol protects human endothelial cells against oxidative insults through activation of Nrf2 and inhibition of mitochondrial dysfunction

Excess intracellular reactive oxygen species (ROS) production is a significant causative factor of many diseases, exemplified by vascular diseases. Mitochondria are a major source of endogenous ROS, which simultaneously induce mitochondrial dysfunction. Nuclear factor-erythroid 2-related factor 2 (Nrf2) represents an important intracellular defense system that protects cells against oxidative insults caused by ROS. Therefore, molecules with the capacities of inducing Nrf2, and preventing mitochondrial dysfunction can inhibit cell apoptosis, and thus are potential drug candidates for the therapy of ROS-mediated vascular diseases. Homoeriodictyol (HE), previously isolated from Viscum articulatum Burm, has been found to be an Nrf2 inducer. In the present study, we investigated its protection on ROS-induced endothelial cell injury using a H₂O₂-induced human umbilical vein EA.hy926 cell oxidative insult model. Our results indicated that HE activated Nrf2 signaling pathway and protected cells against H₂O₂-induced cell damage. HE alleviated H₂O₂-induced loss of mitochondrial membrane potential (MMP), blocked the releases of cytochrome C and apoptosis inducing factor (AIF) from mitochondria, and thus inhibited mitochondria-mediated cell apoptosis. Furthermore, HE inhibited H₂O₂-induced changes of apoptosis-related proteins, such as Bcl-2, Bcl-xL, caspases -3, -9 and PARP. Further study demonstrated that the protection of HE against H₂O₂-induced endothelial cell damage was Nrf2-dependent. Collectively, our observations suggest that HE is capable of counteracting oxidative insults in endothelial cells, and has a potential to be a therapeutic agent against ROS-mediated vascular diseases.

Impact of Obesity and Ozone on the Association Between Particulate Air Pollution and Cardiovascular Disease and Stroke Mortality Among US Adults

Background

Cardiovascular diseases (CVDs) and stroke are the highest and third highest causes of death, respectively, in the whole United States. It is well established that both long‐ and short‐term exposure to particulate air pollution (particulate matter with diameters <2.5 μm [PM_2.5]) increases the risks of both CVD and stroke mortality.

Methods and Results

We combined county‐level data for CVD and stroke mortality, and prevalence of hypertension and obesity, with spatial patterns of PM_2.5 and ozone in a cross‐sectional ecological study. We found significant positive associations between both CVD (β=15.4, P<0.001) and stroke (β=2.7, P<0.001) mortality with PM_2.5. Ozone had significant link with just CVD (β=1372.1, P<0.001). Once poverty, ethnicity, and education were taken into account, there were still significant positive associations between PM_2.5 and both CVD (β=1.2, P<0.001) and stroke (β=1.1, P<0.001) mortality. Moreover, the association between CVD and ozone remained after adjustment for these factors (β=21.8, P<0.001). PM_2.5 and ozone were independent risk factors. The impact of PM_2.5 on CVD and stroke mortality was strongly dependent on the prevalence of obesity. Hypertension partially mediated the associations of PM_2.5 and mortality from CVD and stroke.

Conclusions

There was a spatial association between PM_2.5 exposure and the leading causes of death and disability in United States. The effect of PM_2.5 was considerably greater in areas where obesity is more prevalent. Hypertension is a possible mediator of the association of PM_2.5 and both CVD and stroke.

Evidence for a hyper-reductive redox in a sub-set of heart failure patients

BACKGROUND

Oxidative stress has been linked to heart failure (HF) in humans. Antioxidant-based treatments are often ineffective. Therefore, we hypothesize that some of the HF patients might have a reductive stress (RS) condition. Investigating RS-related mechanisms will aid in personalized optimization of redox homeostasis for better outcomes among HF patients.

METHODS

Blood samples were collected from HF patients (n = 54) and healthy controls (n = 42) and serum was immediately preserved in - 80 °C for redox analysis. Malondialdehyde (MDA; lipid peroxidation) levels by HPLC, reduced glutathione (GSH) and its redox ratio (GSH/GSSG) using enzymatic-recycling assay in the serum of HF patients were measured. Further, the activities of key antioxidant enzymes were analyzed by UV-Vis spectrophotometry. Non-invasive echocardiography was used to relate circulating redox status with cardiac function and remodeling.

RESULTS

The circulatory redox state (GSH/MDA ratio) was used to stratify the HF patients into normal redox (NR), hyper-oxidative (HO), and hyper-reductive (HR) groups. While the majority of the HF patients exhibited the HO (42%), 41% of them had a normal redox (NR) state. Surprisingly, a subset of HF patients (17%) belonged to the hyper-reductive group, suggesting a strong implication for RS in the progression of HF. In all the groups of HF patients, SOD, GPx and catalase were significantly increased while GR activity was significantly reduced relative to healthy controls. Furthermore, echocardiography analyses revealed that 55% of HO patients had higher systolic dysfunction while 62.5% of the hyper-reductive patients had higher diastolic dysfunction.

CONCLUSION

These results suggest that RS may be associated with HF pathogenesis for a subset of cardiac patients. Thus, stratification of HF patients based on their circulating redox status may serve as a useful prognostic tool to guide clinicians designing personalized antioxidant therapies.

Insights From Pre-Clinical and Clinical Studies on the Role of Innate Inflammation in Atherosclerosis Regression

Atherosclerosis, the underlying cause of coronary artery (CAD) and other cardiovascular diseases, is initiated by macrophage-mediated immune responses to lipoprotein and cholesterol accumulation in artery walls, which result in the formation of plaques. Unlike at other sites of inflammation, the immune response becomes maladaptive and inflammation fails to resolve. The most common treatment for reducing the risk from atherosclerosis is low density lipoprotein cholesterol (LDL-C) lowering. Studies have shown, however, that while significant lowering of LDL-C reduces the risk of heart attacks to some degree, there is still residual risk for the majority of the population. We and others have observed “residual inflammatory risk” of atherosclerosis after plasma cholesterol lowering in pre-clinical studies, and that this phenomenon is clinically relevant has been dramatically reinforced by the recent Canakinumab Anti-inflammatory Thrombosis Outcomes Study (CANTOS) trial. This review will summarize the role of the innate immune system, specifically macrophages, in atherosclerosis progression and regression, as well as the pre-clinical and clinical models that have provided significant insights into molecular pathways involved in the resolution of plaque inflammation and plaque regression. Partnered with clinical studies that can be envisioned in the post-CANTOS period, including progress in developing targeted plaque therapies, we expect that pre-clinical studies advancing on the path summarized in this review, already revealing key mechanisms, will continue to be essential contributors to achieve the goals of dampening plaque inflammation and inducing its resolution in order to maximize the therapeutic benefits of conventional risk factor modifications, such as LDL-C lowering.

Lipophilic components of diesel exhaust particles induce pro-inflammatory responses in human endothelial cells through AhR dependent pathway(s)

Background

Exposure to traffic-derived particulate matter (PM), such as diesel exhaust particles (DEP), is a leading environmental cause of cardiovascular disease (CVD), and may contribute to endothelial dysfunction and development of atherosclerosis. It is still debated how DEP and other inhaled PM can contribute to CVD. However, organic chemicals (OC) adhered to the particle surface, are considered central to many of the biological effects. In the present study, we have explored the ability of OC from DEP to reach the endothelium and trigger pro-inflammatory reactions, a central step on the path to atherosclerosis.

Results

Exposure-relevant concentrations of DEP (0.12 μg/cm²) applied on the epithelial side of an alveolar 3D tri-culture, rapidly induced pro-inflammatory and aryl hydrocarbon receptor (AhR)-regulated genes in the basolateral endothelial cells. These effects seem to be due to soluble lipophilic constituents rather than particle translocation. Extractable organic material of DEP (DEP-EOM) was next fractionated with increasing polarity, chemically characterized, and examined for direct effects on pro-inflammatory and AhR-regulated genes in human microvascular endothelial (HMEC-1) cells and primary human endothelial cells (PHEC) from four healthy donors. Exposure-relevant concentrations of lipophilic DEP-EOM (0.15 μg/cm²) induced low to moderate increases in IL-1α, IL-1β, COX2 and MMP-1 gene expression, and the MMP-1 secretion was increased. By contrast, the more polar EOM had negligible effects, even at higher concentrations. Use of pharmacological inhibitors indicated that AhR and protease-activated receptor-2 (PAR-2) were central in regulation of EOM-induced gene expression. Some effects also seemed to be attributed to redox-responses, at least at the highest exposure concentrations tested. Although the most lipophilic EOM, that contained the majority of PAHs and aliphatics, had the clearest low-concentration effects, there was no straight-forward link between chemical composition and biological effects.

Conclusion

Lipophilic and semi-lipophilic chemicals seemed to detach from DEP, translocate through alveolar epithelial cells and trigger pro-inflammatory reactions in endothelial cells at exposure-relevant concentrations. These effects appeared to be triggered by AhR agonists, and involve PAR-2 signaling.

Electronic supplementary material

The online version of this article (10.1186/s12989-018-0257-1) contains supplementary material, which is available to authorized users.

Blocking mitochondrial cyclophilin D ameliorates TSH-impaired defensive barrier of artery

AIMS

Endothelial cells (ECs) constitute the defensive barrier of vasculature, which maintains the vascular homeostasis. Mitochondrial oxidative stress (mitoOS) in ECs significantly affects the initiation and progression of vascular diseases. The higher serum thyroid stimulating hormone (TSH) level is being recognized as a nonconventional risk factor responsible for the increased risk of cardiovascular diseases in subclinical hypothyroidism (SCH). However, effects and underlying mechanisms of elevated TSH on ECs are still ambiguous. We sought to investigate whether cyclophilin D (CypD), emerging as a crucial mediator in mitoOS, regulates effects of TSH on ECs.

METHODS AND RESULTS

SCH patients with TSH > = 10mIU/L showed a positive correlation between serum TSH and endothelin-1 levels. When TSH levels declined to normal in these subjects after levothyroxine therapy, serum endothelin-1 levels were significantly reduced. Supplemented with exogenous thyroxine to keep normal thyroid hormones, thyroid-specific TSH receptor (TSHR)-knockout mice with injection of exogenous TSH exhibited elevated serum TSH levels, significant endothelial oxidative injuries and disturbed endothelium-dependent vasodilation. However, Tshr-/- mice resisted to TSH-impaired vasotonia. We further confirmed that elevated TSH triggered excessive mitochondrial permeability transition pore (mPTP) opening and mitochondrial oxidative damages in mouse aorta, as well as in cultured ECs. Genetic or pharmacological inhibition of CypD (the key regulator for mPTP opening) attenuated TSH-induced mitochondrial oxidative damages and further rescued endothelial functions. Finally, we confirmed that elevated TSH could activate CypD by enhancing CypD acetylation via inhibiting adenosine monophosphate-activated protein kinase/sirtuin-3 signaling pathway in ECs.

CONCLUSIONS

These findings reveal that elevated TSH triggers mitochondrial perturbations in ECs and provide insights that blocking mitochondrial CypD enhances the defensive ability of ECs under TSH exposure.

Horseradish Peroxidase-Encapsulated Hollow Silica Nanospheres for Intracellular Sensing of Reactive Oxygen Species

Reactive oxygen species (ROS) have crucial roles in cell signaling and homeostasis. Overproduction of ROS can induce oxidative damage to various biomolecules and cellular structures. Therefore, developing an approach capable of monitoring and quantifying ROS in living cells is significant for physiology and clinical diagnoses. Some cell-permeable fluorogenic probes developed are useful for the detection of ROS while in conjunction with horseradish peroxidase (HRP). Their intracellular scenario is however hindered by the membrane-impermeable property of enzymes. Herein, a new approach for intracellular sensing of ROS by using horseradish peroxidase-encapsulated hollow silica nanospheres (designated HRP@HSNs), with satisfactory catalytic activity, cell membrane permeability, and biocompatibility, was prepared via a microemulsion method.These HRP@HSNs, combined with selective probes or targeting ligands, could be foreseen as ROS-detecting tools in specific organelles or cell types. As such, dihydrorhodamine 123-coupled HRP@HSNs were used for the qualitative and semi-quantitative analysis of physiological H₂O₂ levels in activated RAW 264.7 macrophages. We envision that this HSNs encapsulating active enzymes can be conjugated with selective probes and targeting ligands to detect ROS in specific organelles or cell types of interest.

Supramolecular Encapsulation and Bioactivity Modulation of a Halonium Ion by Cucurbit[ n]uril ( n = 7, 8)

This is the first time that cucurbit[7]uril and cucurbit[8]uril have been demonstrated to serve as synthetic receptors for a halonium guest species, diphenyleneiodonium, modulating its bioactivities and alleviating its cardiotoxicity, which further expands the onium family of guest molecules for the cucurbit[ n]uril family and provides new insights for halonium-cucurbit[ n]uril host-guest chemistry and its potential applications in pharmaceutical chemistry.

Mitochondria regulate cardiac contraction through ATP-dependent and independent mechanisms

The multipurpose organelle mitochondria play an essential role(s) in controlling cardiac muscle contraction. Mitochondria, not only function as the powerhouses and the energy source of myocytes but also modulate intracellular Ca²⁺ homeostasis, the production of intermediary metabolites/reactive oxygen species (ROS), and other cellular processes. Those molecular events can substantially influence myocardial contraction. Mitochondrial dysfunction is usually associated with cardiac remodelling, and is the causal factor of heart contraction defects in many cases. The manipulation of mitochondria or mitochondria-relevant pathways appears to be a promising therapeutic approach to treat the diseases.

CYP2J2 Expression in Adult Ventricular Myocytes Protects Against Reactive Oxygen Species Toxicity

Cytochrome P450 2J2 isoform (CYP2J2) is a drug-metabolizing enzyme that is highly expressed in adult ventricular myocytes. It is responsible for the bioactivation of arachidonic acid (AA) into epoxyeicosatrienoic acids (EETs). EETs are biologically active signaling compounds that protect against disease progression, particularly in cardiovascular diseases. As a drug-metabolizing enzyme, CYP2J2 is susceptible to drug interactions that could lead to cardiotoxicity. CYP2J2 has been shown to be resistant to induction by canonical CYP inducers such as phenytoin and rifampin. It is, however, unknown how cellular stresses augment CYP2J2 expression. Here, we determine the effects of oxidative stress on gene expression in adult ventricular myocytes. Further, we assess the consequences of CYP2J2 inhibition and CYP2J2 silencing on cells when levels of reactive oxygen species (ROS) are elevated. Findings indicate that CYP2J2 expression increases in response to external ROS or when internal ROS levels are elevated. In addition, cell survival decreases with ROS exposure when CYP2J2 is chemically inhibited or when CYP2J2 expression is reduced using small interfering RNA. These effects are mitigated with external addition of EETs to the cells. Finally, we determined the results of external EETs on gene expression and show that only two of the four regioisomers cause an increase in HMOX1 expression. This work is the first to determine the consequence of cellular stress, specifically high ROS levels, on CYP2J2 expression in human ventricular myocytes and discusses how this enzyme may play an important role in response to cardiac oxidative stress.

Invited review: Whey proteins as antioxidants and promoters of cellular antioxidant pathways

Oxidative stress contributes to cell injury and aggravates several chronic diseases. Dietary antioxidants help the body to fight against free radicals and, therefore, avoid or reduce oxidative stress. Recently, proteins from milk whey liquid have been described as antioxidants. This review summarizes the evidence that whey products exhibit radical scavenging activity and reducing power. It examines the processing and treatment attempts to increase the antioxidant bioactivity and identifies 1 enzyme, subtilisin, which consistently produces the most potent whey fractions. The review compares whey from different milk sources and puts whey proteins in the context of other known food antioxidants. However, for efficacy, the antioxidant activity of whey proteins must not only survive processing, but also upper gut transit and arrival in the bloodstream, if whey products are to promote antioxidant levels in target organs. Studies reveal that direct cell exposure to whey samples increases intracellular antioxidants such as glutathione. However, the physiological relevance of these in vitro assays is questionable, and evidence is conflicting from dietary intervention trials, with both rats and humans, that whey products can boost cellular antioxidant biomarkers.

Chemotherapeutic-Induced Cardiovascular Dysfunction: Physiological Effects, Early Detection-The Role of Telomerase to Counteract Mitochondrial Defects and Oxidative Stress

Although chemotherapeutics can be highly effective at targeting malignancies, their ability to trigger cardiovascular morbidity is clinically significant. Chemotherapy can adversely affect cardiovascular physiology, resulting in the development of cardiomyopathy, heart failure and microvascular defects. Specifically, anthracyclines are known to cause an excessive buildup of free radical species and mitochondrial DNA damage (_mtDNA) that can lead to oxidative stress-induced cardiovascular apoptosis. Therefore, oncologists and cardiologists maintain a network of communication when dealing with patients during treatment in order to treat and prevent chemotherapy-induced cardiovascular damage; however, there is a need to discover more accurate biomarkers and therapeutics to combat and predict the onset of cardiovascular side effects. Telomerase, originally discovered to promote cellular proliferation, has recently emerged as a potential mechanism to counteract mitochondrial defects and restore healthy mitochondrial vascular phenotypes. This review details mechanisms currently used to assess cardiovascular damage, such as C-reactive protein (CRP) and troponin levels, while also unearthing recently researched biomarkers, including circulating _mtDNA, telomere length and telomerase activity. Further, we explore a potential role of telomerase in the mitigation of mitochondrial reactive oxygen species and maintenance of _mtDNA integrity. Telomerase activity presents a promising indicator for the early detection and treatment of chemotherapy-derived cardiac damage.

ROS and redox signaling in myocardial ischemia-reperfusion injury and cardioprotection

Ischemia-reperfusion (IR) injury is central to the pathology of major cardiovascular diseases, such as stroke and myocardial infarction. IR injury is mediated by several factors including the elevated production of reactive oxygen species (ROS), which occurs particularly at reperfusion. The mitochondrial respiratory chain and NADPH oxidases of the NOX family are major sources of ROS in cardiomyocytes. The first part of this review discusses recent findings and controversies on the mechanisms of superoxide production by the mitochondrial electron transport chain during IR injury, as well as the contribution of the NOX isoforms expressed in cardiomyocytes, NOX1, NOX2 and NOX4, to this damage. It then focuses on the effects of ROS on the opening of the mitochondrial permeability transition pore (mPTP), an inner membrane non-selective pore that causes irreversible damage to the heart. The second part analyzes the redox mechanisms of cardiomyocyte mitochondrial protection; specifically, the activation of the hypoxia-inducible factor (HIF) pathway and the antioxidant transcription factor Nrf2, which are both regulated by the cellular redox state. Redox mechanisms involved in ischemic preconditioning, one of the most effective ways of protecting the heart against IR injury, are also reviewed. Interestingly, several of these protective pathways converge on the inhibition of mPTP opening during reperfusion. Finally, the clinical and translational implications of these cardioprotective mechanisms are discussed.

Comparison of volatile anesthetic-induced preconditioning in cardiac and cerebral system: molecular mechanisms and clinical aspects

Volatile anesthetic-induced preconditioning (APC) has shown to have cardiac and cerebral protective properties in both pre-clinical models and clinical trials. Interestingly, accumulating evidences demonstrate that, except from some specific characters, the underlying molecular mechanisms of APC-induced protective effects in myocytes and neurons are very similar; they share several major intracellular signaling pathways, including mediating mitochondrial function, release of inflammatory cytokines and cell apoptosis. Among all the experimental results, cortical spreading depolarization is a relative newly discovered cellular mechanism of APC, which, however, just exists in central nervous system. Applying volatile anesthetic preconditioning to clinical practice seems to be a promising cardio-and neuroprotective strategy. In this review, we also summarized and discussed the results of recent clinical research of APC. Despite all the positive experimental evidences, large-scale, long-term, more precisely controlled clinical trials focusing on the perioperative use of volatile anesthetics for organ protection are still needed.

Inflammatory Response During Myocardial Infarction

The occlusion of a coronary artery by a thrombus generated on a ruptured atherosclerotic plaque has been pursued in the last decades as a determining event for the clinical outcome after myocardial infarction (MI). Yet, MI causes a cell death wave front, which triggers an inflammatory response to clear cellular debris, and which in excess can double the myocardial lesion and influence the clinical prognosis in the short and long term. Accordingly, proper, timely regulated inflammatory response has now been considered a second pivotal player in cardiac recovery after MI justifying the search for pharmacological strategies to modulate inflammatory effectors. This chapter reviews the key events and the main effectors of inflammation after myocardial ischemic insult, as well as the contribution of this phenomenon to the progression of atherosclerosis.

Hemostasis, endothelial stress, inflammation, and the metabolic syndrome

Obesity and the metabolic syndrome (MS) are two of the pressing healthcare problems of our time. The MS is defined as increased abdominal obesity in concert with elevated fasting glucose levels, insulin resistance, elevated blood pressure, and plasma lipids. It is a key risk factor for type 2 diabetes mellitus (T2DM) and for cardiovascular complications and mortality. Here, we review work demonstrating that various aspects of coagulation and hemostasis, as well as vascular reactivity and function, become impaired progressively during chronic ingestion of a western diet, but also acutely after meals. We outline that both T2DM and cardiovascular disease should be viewed as inflammatory diseases and describe that chronic overload of free fatty acids and glucose can trigger inflammatory pathways directly or via increased production of ROS. We propose that since endothelial stress and increases in platelet activity precede inflammation and overt symptoms of the MS, they are likely the first hit. This suggests that endothelial activation and insulin resistance are probably causative in the observed chronic low-level metabolic inflammation, and thus both metabolic and cardiovascular complications linked to consumption of a western diet.

Alterations in mitochondrial respiration and reactive oxygen species in patients poisoned with carbon monoxide treated with hyperbaric oxygen

Background

Carbon monoxide (CO) poisoning is the leading cause of poisoning mortality and morbidity in the USA. Carboxyhemoglobin (COHb) levels are not predictive of severity or prognosis. At this time, the measurement of mitochondrial respiration may serve as a biomarker in CO poisoning. The primary objective of this study was to assess changes in mitochondrial function consisting of respiration and generation of reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMCs) obtained from patients with CO poisoning.

Methods

PBMCs from patients having confirmed CO exposure treated with hyperbaric oxygen or HBO (CO group) and healthy controls (control group) were analyzed with high-resolution respirometry. PBMCs were placed in a 2-ml chamber at a final concentration of 3–4 × 10⁶ cells/ml to simultaneously obtain both respiration and hydrogen peroxide (H₂O₂) production. In the CO group, we performed measurements before and after patients underwent their first HBO treatment.

Results

We enrolled a total of 17 subjects, including 7 subjects with confirmed CO poisoning and 10 subjects in the control group. The CO group included five (71.4%) men and two (28.6%) women having a median COHb of 28%. There was a significant decrease in respiration as measured in pmol O₂ × s^− 1 × 10^− 6 PBMCs in the CO group (pre-HBO) when compared to the control group: maximal respiration (18.4 ± 2.4 versus 35.4 ± 2.8, P < 0.001); uncoupled Complex I respiration (19.8 ± 1.8 versus 41.1 ± 3.8, P < 0.001); uncoupled Complex I + II respiration (32.3 ± 3.2 versus 58.3 ± 3.1, P < 0.001); Complex IV respiration (43.5 ± 2.9 versus 63.6 ± 6.31, P < 0.05). There were also similar differences measured in the CO group before and after HBO treatment with an overall increase in respiration present after treatment. We also determined the rate of H₂O₂ production simultaneously with the measurement of respiration. There was an overall significant increase in the H₂O₂ production in the CO group after HBO treatment when compared to prior HBO treatment and the control group.

Conclusions

In this study, PBMCs obtained from subjects with CO poisoning have an overall decrease in respiration (similar H₂O₂ production) when compared to controls. The inhibition of Complex IV respiration is from CO binding leading to a downstream decrease in respiration at other complexes. PBMCs obtained from CO-poisoned individuals immediately following initial HBO therapy displayed an overall increase in both respiration and H₂O₂ production. The study findings demonstrate that treatment with HBO resulted in improved cellular respiration but a higher H₂O₂ production. It is unclear if the increased production of H₂O₂ in HBO treatment is detrimental.

Maternal diabetes up-regulates NOX2 and enhances myocardial ischaemia/reperfusion injury in adult offspring

Offspring of diabetic mothers are at risk of cardiovascular diseases in adulthood. However, the underlying molecular mechanisms are not clear. We hypothesize that prenatal exposure to maternal diabetes up‐regulates myocardial NOX2 expression and enhances ischaemia/reperfusion (I/R) injury in the adult offspring. Maternal diabetes was induced in C57BL/6 mice by streptozotocin. Glucose‐tolerant adult offspring of diabetic mothers and normal controls were subjected to myocardial I/R injury. Vascular endothelial growth factor (VEGF) expression, ROS generation, myocardial apoptosis and infarct size were assessed. The VEGF‐Akt (protein kinase B)‐mammalian target of rapamycin (mTOR)‐NOX2 signalling pathway was also studied in cultured cardiomyocytes in response to high glucose level. In the hearts of adult offspring from diabetic mothers, increases were observed in VEGF expression, NOX2 protein levels and both Akt and mTOR phosphorylation levels as compared to the offspring of control mothers. After I/R, ROS generation, myocardial apoptosis and infarct size were all significantly higher in the offspring of diabetic mothers relative to offspring of control mothers, and these differences were diminished by in vivo treatment with the NADPH oxidase inhibitor apocynin. In cultured cardiomyocytes, high glucose increased mTOR phosphorylation, which was inhibited by the PI3 kinase inhibitor LY294002. Notably, high glucose‐induced NOX2 protein expression and ROS production were inhibited by rapamycin. In conclusion, maternal diabetes promotes VEGF‐Akt‐mTOR‐NOX2 signalling and enhances myocardial I/R injury in the adult offspring. Increased ROS production from NOX2 is a possible molecular mechanism responsible for developmental origins of cardiovascular disease in offspring of diabetic mothers.

Pharmacological targeting of ROS reaction network in myeloid leukemia cells monitored by ultra-weak photon emission

Acute myeloid leukemia (AML) is a blood cancer that is caused by a disorder of the process that normally generates neutrophils. Function and dysfunction of neutrophils are key to physiologic defense against pathogens as well as pathologies including autoimmunity and cancer. A major mechanism through which neutrophils contribute to health and disease is oxidative burst, which involves rapid release of reactive oxygen species (ROS) generated by a chemical reaction network catalyzed by enzymes including NADPH oxidase and myeloperoxidase (MPO). Due to the involvement of neutrophil-derived reactive oxygen species in many diseases and importance of NADPH oxidase and MPO-mediated reactions in progression and treatment of myeloid leukemia, monitoring this process and modulating it by pharmacological interventions is of great interest. In this work, we have evaluated the potential of a label-free method using ultra-weak photon emission (UPE) to monitor ROS production in neutrophil-like HL60 myeloid leukemia cells. Suppression of ROS was achieved by several drug candidates that target different parts of the reaction pathway. Our results show that UPE can report on ROS production as well as suppression by pharmacological inhibitors. We find that UPE is primarily generated by MPO catalyzed reaction and thus will be affected when an upstream reaction is pharmacologically modulated.

Reactive Oxygen Species Generated by CD45-Cells Distinct from Leukocyte Population in Platelet Concentrates Is Correlated with the Expression and Release of Platelet Activation Markers during Storage

Background

Platelet stimulation with agonists is accompanied by the generation of reactive oxygen species (ROS) which promotes further platelet activation and aggregation. Considering different cell populations in platelet concentrates (PCs), this study investigates the correlation of ROS generation with the expression and release of platelet activation markers during storage.

Methods

Samples obtained from 6 PCs were subjected to flow cytometry and ELISA to evaluate the expression and shedding of platelet P-selectin or CD40L during storage. Intracellular ROS were detected in either CD45- or CD45+ population by flow cytometry using dihydrorhodamine 123, while ROS production was analyzed in both P-selectin+ or P-selectin- and CD40L+ or CD40L- populations. To further evaluate the correlation between ROS generation and release function, TRAP-stimulated platelets were also subjected to flow cytometry analysis.

Results

ROS detected in the CD45-population (leukocyte-free platelets) was significantly increased by fMLP and PMA. P-selectin- or CD40L- platelet did not show significant amount of ROS. Total ROS generation was significantly increased during platelet storage (day 0 vs. day 5; p = 0.0002) while this increasing pattern was directly correlated with the expression of P-selectin (r = 0.72; p = 0.0001) and CD40L (r = 0.69; p = 0.0001). ROS generations were significantly correlated with ectodomain shedding of these pro-inflammatory molecules.

Conclusion

Our data confirmed increasing levels of intracellular ROS generation in both platelets (CD45-) and platelet-leukocyte aggregates (CD45+) during PC storage. The amount of detected ROS is directly correlated with platelet activation and release in each population while platelet-leukocyte aggregates generate higher levels of ROS than single platelets.

Oxidative stress markers and antioxidant activity in patients admitted to Intensive Care Unit with acute myocardial infarction

OBJECTIVES

The aim of the study was to compare the levels of oxidative stress biomarkers and antioxidants in acute myocardial infarction (AMI) patients with healthy individuals and to investigate the effectiveness of these parameters as risk or illness indicators.

METHODOLOGY

This study was conducted on AMI patients admitted to Intensive Care Unit of Al-Salam Hospital and Ibn-Sina Hospital in Mosul, Iraq. Considering inclusion and exclusion criteria, a total of 161 patients and 156 healthy individuals in the age group of 30-80 years were selected for the study. The study groups were screened by estimating cardiac markers and electrocardiography (ECG).

RESULTS

The results indicated a significant increase in the level of serum malondialdehyde, peroxynitrite, and uric acid (P< 0.001). A minor increase in the serum ceruloplasmin level was observed in patients with AMI as compared to healthy individuals. The study also observed a significant decrease in the level of glutathione, Vitamin E, and Vitamin C (P< 0.001), with no significant difference in the level of Vitamin A in patients with AMI.

CONCLUSION

The imbalance in the oxidative status and antioxidant activity in AMI patients reflects the importance of measuring the level of serum oxidative stress biomarkers and antioxidants as a diagnostic and prognostic tool for the medical management of AMI. Oxidative stress biomarkers and antioxidants might be good predictors or indicators for the risk of AMI. Oxidative stress markers contribute in the pathogenesis of AMI and excess of reactive oxygen species overwhelm the stability of the antioxidants.

Spatial perspectives in the redox code-Mass spectrometric proteomics studies of moonlighting proteins

The Redox Code involves specific, reversible oxidative changes in proteins that modulate protein tertiary structure, interactions, trafficking, and activity, and hence couple the proteome to the metabolic/oxidative state of cells. It is currently a major focus of study in cell biology. Recent studies of dynamic cellular spatial reorganization with MS-based subcellular-spatial-razor proteomics reveal that protein constituents of many subcellular structures, including mitochondria, the endoplasmic reticulum, the plasma membrane, and the extracellular matrix, undergo changes in their subcellular abundance/distribution in response to oxidative stress. These proteins are components of a diverse variety of functional processes spatially distributed across cells. Many of the same proteins are involved in response to suppression of DNA replication indicate that oxidative stress is strongly intertwined with DNA replication/proliferation. Both are replete with networks of moonlighting proteins that show coordinated changes in subcellular location and that include primary protein actuators of the redox code involved in the processing of NAD⁺ /NADH, NADP⁺ /NADPH, Cys/CySS, and GSH/GSSG redox couples. Small groups of key proteins such as {KPNA2, KPNB1, PCNA, PTMA, SET} constitute "spatial switches" that modulate many nuclear processes. Much of the functional response involves subcellular protein trafficking, including nuclear import/export processes, vesicle-mediated trafficking, the endoplasmic reticulum/Golgi pathway, chaperone-assisted processes, and other transport systems. This is not visible to measurements of total protein abundance by transcriptomics or proteomics. Comprehensive pictures of cellular function will require collection of data on the subcellular transport and local functions of many moonlighting proteins, especially of those with critical roles in spatial coordination across cells. The proteome-wide analysis of coordinated changes in abundance and trafficking of proteins offered by MS-based proteomics has a unique, crucial role to play in deciphering the complex adaptive systems that underlie cellular function. © 2016 Wiley Periodicals, Inc. Mass Spec Rev.

The role of declining adaptive homeostasis in ageing

Adaptive homeostasis is "the transient expansion or contraction of the homeostatic range for any given physiological parameter in response to exposure to sub-toxic, non-damaging, signalling molecules or events, or the removal or cessation of such molecules or events" (Davies, 2016). Adaptive homeostasis enables biological systems to make continuous short-term adjustments for optimal functioning despite ever-changing internal and external environments. Initiation of adaptation in response to an appropriate signal allows organisms to successfully cope with much greater, normally toxic, stresses. These short-term responses are initiated following effective signals, including hypoxia, cold shock, heat shock, oxidative stress, exercise-induced adaptation, caloric restriction, osmotic stress, mechanical stress, immune response, and even emotional stress. There is now substantial literature detailing a decline in adaptive homeostasis that, unfortunately, appears to manifest with ageing, especially in the last third of the lifespan. In this review, we present the hypothesis that one hallmark of the ageing process is a significant decline in adaptive homeostasis capacity. We discuss the mechanistic importance of diminished capacity for short-term (reversible) adaptive responses (both biochemical and signal transduction/gene expression-based) to changing internal and external conditions, for short-term survival and for lifespan and healthspan. Studies of cultured mammalian cells, worms, flies, rodents, simians, apes, and even humans, all indicate declining adaptive homeostasis as a potential contributor to age-dependent senescence, increased risk of disease, and even mortality. Emerging work points to Nrf2-Keap1 signal transduction pathway inhibitors, including Bach1 and c-Myc, both of whose tissue concentrations increase with age, as possible major causes for age-dependent loss of adaptive homeostasis.

Erythrocytes, leukocytes and platelets as a source of oxidative stress in chronic vascular diseases: Detoxifying mechanisms and potential therapeutic options

Oxidative stress is involved in the chronic pathological vascular remodelling of both abdominal aortic aneurysm and occlusive atherosclerosis. Red blood cells (RBCs), leukocytes and platelets present in both, aneurysmal intraluminal thrombus and intraplaque haemorraghes, could be involved in the redox imbalance inside diseased arterial tissues. RBCs haemolysis may release the pro-oxidant haemoglobin (Hb), which transfers heme to tissue and low-density lipoproteins. Heme-iron potentiates molecular, cell and tissue toxicity mediated by leukocytes and other sources of reactive oxygen species (ROS). Polymorphonuclear neutrophils release myeloperoxidase and, along with activated platelets, produce superoxide mediated by NADPH oxidase, causing oxidative damage. In response to this pro-oxidant milieu, several anti-oxidant molecules of plasma or cell origin can prevent ROS production. Free Hb binds to haptoglobin (Hp) and once Hp-Hb complex is endocytosed by CD163, liberated heme is converted into less toxic compounds by heme oxygenase-1. Iron homeostasis is mainly regulated by transferrin, which transports ferric ions to other cells. Transferrin-bound iron is internalised via endocytosis mediated by transferrin receptor. Once inside the cell, iron is mainly stored by ferritin. Other non hemo-iron related antioxidant enzymes (e.g. superoxide dismutase, catalase, thioredoxin and peroxiredoxin) are also involved in redox modulation in vascular remodelling. Oxidative stress is a main determinant of chronic pathological remodelling of the arterial wall, partially linked to the presence of RBCs, leukocytes, platelets and oxidised fibrin within tissue and to the imbalance between pro-/anti-oxidant molecules. Understanding the complex mechanisms underlying redox imbalance could help to define novel potential targets to decrease atherothrombotic risk.

The Glia-Neuron Lactate Shuttle and Elevated ROS Promote Lipid Synthesis in Neurons and Lipid Droplet Accumulation in Glia via APOE/D

Elevated reactive oxygen species (ROS) induce the formation of lipids in neurons that are transferred to glia, where they form lipid droplets (LDs). We show that glial and neuronal monocarboxylate transporters (MCTs), fatty acid transport proteins (FATPs), and apolipoproteins are critical for glial LD formation. MCTs enable glia to secrete and neurons to absorb lactate, which is converted to pyruvate and acetyl-CoA in neurons. Lactate metabolites provide a substrate for synthesis of fatty acids, which are processed and transferred to glia by FATP and apolipoproteins. In the presence of high ROS, inhibiting lactate transfer or lowering FATP or apolipoprotein levels decreases glial LD accumulation in flies and in primary mouse glial-neuronal cultures. We show that human APOE can substitute for a fly glial apolipoprotein and that APOE4, an Alzheimer's disease susceptibility allele, is impaired in lipid transport and promotes neurodegeneration, providing insights into disease mechanisms.

Corin protects H2O2-induced apoptosis through PI3K/AKT and NF-κB pathway in cardiomyocytes

BACKGROUND

The functional role of corin in H₂O₂-induced apoptosis is largely unexplored. The present study investigated the protective role of corin against cell injury by possible involvement of PI3K/AKT and NF-kB signaling pathways in cardiomyocytes.

METHOD

Cardiomyocytes H9c2 and HL-1 cells were used in the study. Cell viability was measured using CCK-8 assay; cell apoptosis was analyzed by flow cytometry, TUNEL assay, and western blot; and cell migration was measured using wound healing assay. The fluorescent intensities of reactive oxygen species (ROS) were measured using a flow cytometer. Quantitative RT-PCR was used to measure the mRNA expression of corin. Western blot was used to measure the protein expression of corin, apoptosis-related proteins (Bax, cleaved-Caspase-3 and -9), and PI3K/AKT and NF-κB signaling pathway proteins.

RESULTS

Treatment with H₂O₂ (150μM, 6h) significantly decreased cell viability and relative migration, increased apoptosis, and decreased the expression of corin in H9c2 and HL-1 cells. Overexpression of corin alleviated the H₂O₂-induced cell injury by increasing cell viability and migration and decreasing apoptosis in the cardiomyocytes. Overexpression of corin also decreased the ROS level in the cardiomyocytes likely through upregulating HIF-1α. These effects of corin on the cell injury might be mediated via the corin-induced activations of PI3K/AKT and NF-κB signaling pathways.

CONCLUSION

Overexpression of corin protected cardiomyocytes from H₂O₂-induced injury by decreasing apoptosis and ROS level via activations of the PI3K/AKT and NF-κB signaling pathways and upregulating HIF-1α.

Systematic evaluation of bioactive components and antioxidant capacity of some new and common bayberry cultivars using an in vitro gastrointestinal digestion method

This study was aimed to investigate the impact of in vitro gastrointestinal digestion on some common and new bayberry cultivars. The contents of total phenolics (246-669mg gallic acid equivalents/kg FW (fresh weight)), flavonoids (116-689mg quercetin-3-O-rutinoside equivalents/kg FW), procyanidins (28-133mg catechin equivalents/kg FW) and anthocyanins (1-7mg cyaniding-3-O-glucoside equivalents/kg FW) were detected in digested cultivars. HPLC-TOF-MS analysis identified 17 phenolic compounds in digested sample. Among all digested cultivars, the new cultivars Anhaizaomei (ABTS, IC₅₀=2.95mg/mL; FRAP, 401.32mg vitamin C equivalents (VCE)/kg FW) and Yingsi (ABTS, IC₅₀=3.28mg/mL; FRAP, 400.81mg VCE/kg FW) showed better in vitro antioxidant capacity. Further cellular assay indicated that the common cultivar Dongkui (2mg/mL) possessed the strongest ROS scavenging activity. The comprehensive evaluation of bioactive components and antioxidant properties using principal component analysis suggests that common cultivar Dongkui, new cultivars Yingsi and Anhaizaomei could be considered as dietary supplements.

Cardiac Nonmyocyte Cell Functions and Crosstalks in Response to Cardiotoxic Drugs

The discovery of the molecular mechanisms involved in the cardiac responses to anticancer drugs represents the current goal of cardio-oncology research. The oxidative stress has a pivotal role in cardiotoxic responses, affecting the function of all types of cardiac cells, and their functional crosstalks. Generally, cardiomyocytes are the main target of research studies on cardiotoxicity, but recently the contribution of the other nonmyocyte cardiac cells is becoming of growing interest. This review deals with the role of oxidative stress, induced by anticancer drugs, in cardiac nonmyocyte cells (fibroblasts, vascular cells, and immune cells). The alterations of functional interplays among these cardiac cells are discussed, as well. These interesting recent findings increase the knowledge about cardiotoxicity and suggest new molecular targets for both diagnosis and therapy.

Cardioprotective Effect of Resveratrol in a Postinfarction Heart Failure Model

Despite great advances in therapies observed during the last decades, heart failure (HF) remained a major health problem in western countries. In order to further improve symptoms and survival in patients with heart failure, novel therapeutic strategies are needed. In some animal models of HF resveratrol (RES), it was able to prevent cardiac hypertrophy, contractile dysfunction, and remodeling. Several molecular mechanisms are thought to be involved in its protective effects, such as inhibition of prohypertrophic signaling molecules, improvement of myocardial Ca²⁺ handling, regulation of autophagy, and the reduction of oxidative stress and inflammation. In our present study, we wished to further examine the effects of RES on prosurvival (Akt-1, GSK-3β) and stress signaling (p38-MAPK, ERK 1/2, and MKP-1) pathways, on oxidative stress (iNOS, COX-2 activity, and ROS formation), and ultimately on left ventricular function, hypertrophy and fibrosis in a murine, and isoproterenol- (ISO-) induced postinfarction heart failure model. RES treatment improved left ventricle function, decreased interstitial fibrosis, cardiac hypertrophy, and the level of plasma BNP induced by ISO treatment. ISO also increased the activation of P38-MAPK, ERK1/2^{Thr183-Tyr185}, COX-2, iNOS, and ROS formation and decreased the phosphorylation of Akt-1, GSK-3β, and MKP-1, which were favorably influenced by RES. According to our results, regulation of these pathways may also contribute to the beneficial effects of RES in HF.

Diverse cellular actions of tert-butylhydroquinone, a food additive, on rat thymocytes

Tertiary butylhydroquinone (TBHQ) is a food additive that possesses antioxidant activity. Its alternative applications have been explored in recent studies. However, there is controversy regarding safety. In this study using rat thymocytes, the cellular actions of TBHQ at sublethal concentrations were examined. TBHQ at concentrations of 3 μM or more elevated intracellular Zn²⁺ concentration ([Zn²⁺]_i) in a dose-dependent manner, by increasing membrane Zn²⁺ permeability and releasing Zn²⁺ from cellular stores. TBHQ at 30 μM significantly increased side scatter (cell density) and the exposure of phosphatidylserine (PS) on cell membrane surfaces. It also decreased cellular glutathione (GSH) content without affecting cell lethality. Forward scatter was attenuated by 100 μM TBHQ. Thus, it is considered that TBHQ at sublethal concentrations (30 μM or less) exerts some adverse actions on cells. TBHQ at 10-30 μM attenuated the increase in cell lethality induced by hydrogen peroxide (H₂O₂), while potentiation of H₂O₂ cytotoxicity by 100 μM TBHQ was observed. The range of concentrations of TBHQ from benefit to toxicity under in vitro conditions may be 10-30 μM. Although TBHQ exhibits antioxidative actions at concentrations that are lower than those which elicit adverse cellular effects, sublethal levels of TBHQ cause some adverse actions that may be clinically concerned.

Adipose-derived stem cell-released osteoprotegerin protects cardiomyocytes from reactive oxygen species-induced cell death

Background

The paracrine effect is likely the major mechanism of the adipose-derived stem cell (ASC)-mediated cardioprotective effect. However, the exact composition and nature of ASC-released paracrine factors remain elusive. In the present study, we examined the effect of osteoprotegerin (OPG), a stem cell-released decoy receptor for death ligand, on the survival of cardiomyocytes exposed to oxidative stress.

Methods

The production of OPG from ASCs under oxidative stress was determined by ELISA and immunohistochemistry. The effects of OPG and the OPG-containing conditioned media of ASCs on the survival of cardiomyocytes were determined using a cell viability assay.

Results

Hydrogen peroxide (H₂O₂) significantly increased OPG production from ASCs in vitro, and OPG production from the ASCs transplanted into the ischemia–reperfusion-injured heart was also observed. OPG significantly attenuated cardiomyocyte death in vitro. OPG-containing conditioned media of ASCs also significantly protected cardiomyocytes. Delivery of siRNA specific to OPG significantly decreased the OPG production of ASCs, and also offset the protective effect of the conditioned media of ASCs.

Conclusions

Our study strongly suggests that OPG is one of the prosurvival factors released from ASCs that may contribute to the ASC-mediated cardioprotection and calls for further studies to elucidate detailed underlying mechanisms.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0647-6) contains supplementary material, which is available to authorized users.

Characterization of simvastatin acid uptake by organic anion transporting polypeptide 3A1 (OATP3A1) and influence of drug-drug interaction

Human organic anion transporting polypeptide 3A1 (OATP3A1) is predominately expressed in the heart. The ability of OATP3A1 to transport statins into cardiomyocytes is unknown, although other OATPs are known to mediate the uptake of statin drugs in liver. The pleiotropic effects and uptake of simvastatin acid were analyzed in primary human cardiomyocytes and HEK293 cells transfected with the OATP3A1 gene. Treatment with simvastatin acid reduced indoxyl sulfate-mediated reactive oxygen species and modulated OATP3A1 expression in cardiomyocytes and HEK293 cells transfected with the OATP3A1 gene. We observed a pH-dependent effect on OATP3A1 uptake, with more efficient simvastatin acid uptake at pH5.5 in HEK293 cells transfected with the OATP3A1 gene. The Michaelis-Menten constant (K_m) for simvastatin acid uptake by OATP3A1 was 0.017±0.002μM and the V_max was 0.995±0.027fmol/min/10⁵ cells. Uptake of simvastatin acid was significantly increased by known (benzylpenicillin and estrone-3-sulfate) and potential (indoxyl sulfate and cyclosporine) substrates of OATP3A1. In conclusion, the presence of OATP3A1 in cardiomyocytes suggests that this transporter may modulate the exposure of cardiac tissue to simvastatin acid due to its enrichment in cardiomyocytes. Increases in uptake of simvastatin acid by OATP3A1 when combined with OATP substrates suggest the potential for drug-drug interactions that could influence clinical outcomes.