Reduced Reactive Oxygen Species Generation Research Articles

Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress

IntroductionThe etiology of radiation-induced erectile dysfunction (ED) is complex and multifactorial, and it appears to be mainly atherogenic. AimTo focus on vascular aspects of radiation-induced ED and to elucidate whether the protective effects of sildenafil are mediated by attenuation of oxidative stress and apoptosis in the endothelial cells. MethodsBovine aortic endothelial cells (BAECs), with or without pretreatment of sildenafil (5 μM at 5 minutes before radiation), were used to test endothelial dysfunction in response to external beam radiation at 10–15 Gy. Generation of reactive oxygen species (ROS) was studied. Extracellular hydrogen peroxide (H2O2) was measured using the Amplex Red assay and intracellular H2O2 using a fluorescent sensor. In addition, ROS superoxide (O2•-) was measured using a O2•- chemiluminescence enhancer. Both H2O2 and O2•- are known to reduce the bioavailability of nitric oxide, which is the most significant chemical mediator of penile erection. Generation of cellular peroxynitrite (ONOO−) was measured using a chemiluminescence assay with the PNCL probe. Subsequently, we measured the activation of acid sphingomyelinase (ASMase) enzyme by radioenzymatic assay using [14C-methylcholine] sphingomyelin as substrate, and the generation of the proapoptotic C16-ceramide was assessed using the diacylglycerol kinase assay. Endothelial cells apoptosis was measured as a readout of these cells’ dysfunction. Main Outcome MeasuresSingle high-dose radiation therapy induced NADPH oxidases (NOXs) activation and ROS generation via the proapoptotic ASMase/ceramide pathway. The radio-protective effect of sildenafil on BAECs was due to inhibition of this pathway. ResultsHere, we demonstrate for the first time that radiation activated NOXs and induced generation of ROS in BAECs. In addition, we showed that sildenafil significantly reduced radiation-induced O2•- and as a result there was reduction in the generation of peroxynitrite in these cells. Subsequently, sildenafil protected the endothelial cells from radiation therapy-induced apoptosis. Strengths and LimitationsThis is the first study demonstrating that single high-dose radiation therapy induced NOXs activation, resulting in the generation of O2•- and peroxynitrite in endothelial cells. Sildenafil reduced ROS generation by inhibiting the ASMase/ceramide pathway. These studies should be followed in an animal model of ED. ConclusionsThis study demonstrated that sildenafil protects BAECs from radiation-induced oxidative stress by reducing NOX-induced ROS generation, thus resulting in decreased endothelial dysfunction. Therefore, it provides a potential mechanism to better understand the atherogenic etiology of postradiation ED.Wortel RC, Mizrachi A, Li H, et al. Sildenafil Protects Endothelial Cells From Radiation-Induced Oxidative Stress. J Sex Med 2019;16:1721–1733.

Prospective role of mitochondrial apoptotic pathway in mediating GMG-ITC to reduce cytotoxicity in H2O2-induced oxidative stress in differentiated SH-SY5Y cells

The antioxidant and neuroprotective activity of Glucomoringin isothiocyanate (GMG-ITC) have been reported in in vivo and in vitro models of neurodegenerative diseases. However, its neuroprotective role via mitochondrial-dependent pathway in a noxious environment remains unknown. The main objective of the present study was to unveil the mitochondrial apoptotic genes’ profile and prospectively link with neuroprotective activity of GMG-ITC through its ROS scavenging. The results showed that pre-treatment of differentiated SH-SY5Y cells with 1.25 μg/mL purified isolated GMG-ITC, significantly reduced reactive oxygen species (ROS) production level, compared to H2O2 control group, as evidenced by flow cytometry-based evaluation of ROS generation. Presence of GMG-ITC prior to development of oxidative stress condition, downregulated the expression of cyt-c, p53, Apaf-1, Bax, CASP3, CASP8 and CASP9 genes with concurrent upregulation of Bcl-2 gene in mitochondrial apoptotic signalling pathway. Protein Multiplex revealed significant decreased in cyt-c, p53, Apaf-1, Bax, CASP8 and CASP9 due to GMG-ITC pre-treatment in oxidative stress condition. The present findings speculated that pre-treatment with GMG-ITC may alleviate oxidative stress condition in neuronal cells by reducing ROS production level and protect the cells against apoptosis via neurodegenerative disease potential pathways.

Isosteviol prevents the development of isoprenaline‑induced myocardial hypertrophy.

Isosteviol sodium (STVNa), which is a derivate of the natural sweet-tasting glycoside stevioside, has recently been developed and it has been determined that this compound exhibits neuro- and cardio-protective properties. In the current study, whether STVNa interferes with the development of cardiac hypertrophy, which is induced by isoprenaline (Iso), was investigated in an experimental rat model. Rats were treated with a vehicle (0.9% NaCl; control), isoprenaline (Iso; 5 mg/kg) or Iso (5 mg/kg) with STVNa (4 mg/kg; Iso + STVNa). Cardiomyocytes were isolated using enzymatic dissociation and were treated with 5 µM Iso for 24 h and co-treated with 5 µM STVNa. Brain natriuretic peptide (BNP) mRNA expression was determined using PCR analysis. Cell surface area, intracellular reactive oxygen species (ROS), mitochondrial transmembrane potential (ΔΨm), cytoplasmic Ca2+ and Ca2+ and contractile function were examined using a laser scanning confocal microscope. The current study demonstrated that STVNa inhibited Iso-induced cardiac hypertrophy by inhibiting cardiomyocyte size. STVNa significantly reduced cell surface area and decreased BNP mRNA expression in ventricular cardiomyocyte Iso-induced hypertrophy. STVNa was also revealed to restore ΔΨm and reduce ROS generation and intracellular Ca2+ concentration when compared with the Iso-treated group. Additionally, STVNa preserved Ca2+ transients in hypertrophic cardiomyocytes. In conclusion, the present study demonstrated that STVNa protects against Iso-induced myocardial hypertrophy by reducing oxidative stress, restoring ΔΨm and maintaining Ca2+ homeostasis.

Coriolus versicolor-derived protein-bound polysaccharides trigger the caspase-independent cell death pathway in amelanotic but not melanotic melanoma cells.

We have investigated the potential cell death mechanism promoted by Coriolus versicolor fungus-derived protein-bound polysaccharides (PBPs) in melanoma cells. Knowing that melanogenesis has the potential to affect the tumor behavior and melanoma therapy outcome, the cytotoxic effects of PBPs were evaluated in human SKMel-188 melanoma cell line, whose phenotype, amelanotic versus pigmented, depends on the concentration of melanin precursors in the culture medium. Our results showed that inhibitory effect of PBPs (100 and 200 μg/ml) towards melanoma cells is inversely associated with the pigmentation level. This cytotoxicity induced in nonpigmented melanoma cells by PBPs was caspase-independent; however, it was accompanied by an increased intracellular reactive oxygen species (ROS) generation. The ROS production was controlled by c-Jun N-terminal kinase (JNK) because SP600125, a JNK inhibitor, significantly reduced ROS generation and protected cells against PBPs-induced death. We also found that PBPs-induced lactate dehydrogenase release in amelanotic melanoma cells was abolished by co-treatment with receptor-interacting serine/threonine-protein kinase 1 inhibitor, implying engagement of this kinase in PBPs-induced death pathway. The results suggest that PBPs induce an alternative programmed cell death, regulated by receptor-interacting protein-1 and ROS and that this process is modified by melanin content in melanoma cells. These findings are remarkable when considering the use of commercially available Coriolus versicolor by patients who suffer from melanoma cancer.

Dapagliflozin Prevents NOX- and SGLT2-Dependent Oxidative Stress in Lens Cells Exposed to Fructose-Induced Diabetes Mellitus.

Purpose: Cataracts in patients with diabetes mellitus (DM) are a major cause of blindness in developed and developing countries. This study aims to examine whether the generation of reactive oxygen species (ROS) via the increased expression of glucose transporters (GLUTs) and the receptor for advanced glycation end products (RAGE) influences the cataract development in DM. Methods: Lens epithelial cells (LECs) were isolated during cataract surgery from patients without DM or with DM, but without diabetic retinopathy. In a rat model, fructose (10% fructose, 8 or 12 weeks) with or without dapagliflozin (1.2 mg/day, 2 weeks) treatment did induce DM, as verified by blood pressure and serum parameter measurements. Immunofluorescence stainings and immunoblottings were used to quantify the protein levels. Endogenous O2˙¯ production in the LECs was determined in vivo with dihydroethidium stainings. Results: We investigated that GLUT levels in LECs differed significantly, thus leading to the direct enhancement of RAGE-associated superoxide generation in DM patients with cataracts. Superoxide production was significantly higher in LECs from rats with fructose-induced type 2 DM, whereas treatment with the sodium-glucose cotransporter 2 (SGLT2) inhibitor dapagliflozin prevented this effect in fructose-fed rats. Protein expression levels of the sodium/glucose cotransporter 2 (SGLT2), GLUT1, GLUT5, the nicotinamide adenine dinucleotide phosphate reduced form (NADPH) oxidase subunit p67-phox, NOX2/4 and RAGE were upregulated in fructose-fed animals, whereas dapagliflozin treatment reversed these effects. Conclusions: In rats with fructose-induced DM, dapagliflozin downregulates RAGE-induced NADPH oxidase expression in LECs via the inactivation of GLUTs and a reduction in ROS generation. These novel findings suggest that the SGLT2 inhibitor dapagliflozin may be a candidate for the pharmacological prevention of cataracts in patients with DM.

The Neuroprotective Effect of Steroid Receptor Coactivator-Interacting Protein (SIP) in Astrocyte Model of 1-Methyl-4-Phenylpyridinium (MPP⁺)-Induced Parkinson's Disease.

BackgroundThe purpose of this study was to investigate the role and mechanism of steroid receptor coactivator-interacting protein (SIP) in an astrocyte model of 1-methyl-4-phenylpyridinium (MPP+)-induced Parkinson’s disease.Material/MethodsTo perform our study, a Parkinson’s disease cell model was established by treating the rat glioblastoma cell line C6 with MPP+. SIP was overexpressed in C6 cells using SIP-plasmid. Cell viability and apoptosis were analyzed using MTT assay and flow cytometer respectively. Tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels were detected using enzyme linked immunosorbent assay and quantitative reverse transcription PCR. Besides, lactate dehydrogenase (LDH) release, reactive oxygen species (ROS) production, and superoxide dismutase (SOD) enzyme activity were determined in the present study. For protein and mRNA detection, western blot assay, and qRT-PCR were performed respectively.ResultsSIP was decreased in MPP+-induced C6 cells. SIP overexpression relieved MPP+-induced cytotoxicity of C6 cells, displayed as increased cell viability and reduced cell apoptosis and reduced LDH release. Besides, SIP inhibited MPP+-induced inflammatory response and oxidative stress, evidenced by decreased levels of inflammatory factors (TNF-α and IL-1β), reduced ROS generation and enhanced SOD activity. Moreover, MPP+-induced nuclear factor-κB activation was inhibited by SIP overexpression.ConclusionsSIP was downregulated in Parkinson’s disease and it played a protective role in the development Parkinson’s disease, thus may be a promising target for Parkinson’s disease treatment.

A loop involving NRF2, miR-29b-1-5p and AKT, regulates cell fate of MDA-MB-231 triple-negative breast cancer cells.

The present study shows that nuclear factor erythroid 2-related factor 2 (NRF2) and miR-29b-1-5p are two opposite forces which could regulate the fate of MDA-MB-231 cells, the most studied triple-negative breast cancer (TNBC) cell line. We show that NRF2 activation stimulates cell growth and markedly reduces reactive oxygen species (ROS) generation, whereas miR-29b-1-5p overexpression increases ROS generation and reduces cell proliferation. Moreover, NRF2 downregulates miR-29b-1-5p expression, whereas miR-29b-1-5p overexpression decreases p-AKT and p-NRF2. Furthermore, miR-29b-1-5p overexpression induces both inhibition of DNA N-methyltransferases (DNMT1, DNMT3A, and DNMT3B) expression and re-expression of HIN1, RASSF1A and CCND2. Conversely, NRF2 activation induces opposite effects. We also show that parthenolide, a naturally occurring small molecule, induces the expression of miR-29b-1-5p which could suppress NRF2 activation via AKT inhibition. Overall, this study uncovers a novel NRF2/miR-29b-1-5p/AKT regulatory loop that can regulate the fate (life/death) of MDA-MB-231 cells and suggests this loop as therapeutic target for TNBC.

Combination of metformin and p38 MAPK inhibitor, SB203580, reduced myocardial ischemia/reperfusion injury in non‑obese type 2 diabetic Goto‑Kakizaki rats

Diabetic cardiomyopathy, especially myocardial ischemia reperfusion (I/R) injury, is a major cause of morbidity and mortality in type 2 diabetic patients. The increasing of basal p38 MAP Kinase (p38 MAPK) activation is a major factor that aggravates cardiac death on diabetic cardiomyopathy. In addition, metformin also shows cardio-protective effects on myocardial ischemia/reperfusion injury. In this study, we investigated the effect of the combination between metformin and p38 MAPK inhibitor (SB203580) in diabetic rats subjected to I/R injury. H9c2 cells were induced into a hyperglycemic condition and treated with metformin, SB203580 or the combination of metformin and SB203580. In addition, cells in both the presence and absence of drug treatment were subjected to simulated ischemia/reperfusion injury. Cell viability and cellular reactive oxygen species (ROS) were determined. Moreover, the Goto-Kakizaki (GK) rats were treated with metformin, SB203580, and the combination of metformin and SB203580 for 4 weeks. Diabetic parameters and cardiac functions were assessed. Finally, rat hearts were induced ischemia/reperfusion injury for the purpose of infarct size analysis and determination of signal transduction. A high-glucose condition did not reduce cell viability but significantly increased ROS production and significantly decreased cell viability after induced sI/R. Treatment using drugs was shown to reduce ROS generation and cardiac cell death. The GK rats displayed diabetic phenotype by increasing diabetic parameters and these parameters were significantly decreased when treated with drugs. Treatment with metformin or SB203580 could significantly reduce the infarct size. Interestingly, the combination of metformin and SB203580 could enhance cardio-protective ability. Myocardial I/R injury significantly increased p38 MAPK phosphorylation, Bax/Bcl-2 ratio and caspase-3 level. Treatment with drugs significantly decreased the p38 MAPK phosphorylation, Bax/Bcl-2 ratio, caspase-3 level and increased Akt phosphorylation. In conclusion, using the combination of metformin and SB203580 shows positive cardio-protective effects on diabetic ischemic cardiomyopathy.

Effect of Moringa oleifera stem extract on hydrogen peroxide-induced opacity of cultured mouse lens

BackgroundMoringa oleifera, also known as horseradish tree or drumstick tree, has strong antioxidant properties. In the present study, we investigated the potential effect of Moringa oleifera stem extract (MOSE) on cataract formation induced by oxidative stress in cultured mouse lenses.MethodsMouse lenses cultured in vitro were pretreated with MOSE (0.5 and 1 mg/mL) for 24 h. Then, 1 mM hydrogen peroxide was added, and mouse lenses were cultured for a further 24 h. The medium was then changed to normal culture medium. After 48 h, lens opacification, reactive oxygen species (ROS) generation, reduced glutathione (GSH) content, and activities of superoxide dismutase (SOD) and catalase (CAT) were measured in lens tissues. In addition, the protein expression of peroxisome proliferator-activated receptor alpha (PPARα), a nuclear receptor with potential benefits to improve vision-threatening eye diseases, was assayed.ResultsMOSE (1 mg/mL) alleviated lens opacification, reduced ROS generation, increased GSH content, and elevated SOD and CAT activities in cultured lenses. Moreover, MOSE upregulated the expressions of SOD, CAT, and PPARα.ConclusionsThis study showed that MOSE alleviates oxidative stress-induced cataract formation, and the mechanism of the effect is mainly related to its improvement of the endogenous antioxidant system in the lens.

Antagonistic effect of co-exposure to short-multiwalled carbon nanotubes and benzo[a]pyrene in human lung cells (A549).

In theenvironment, co-exposure to short-multiwalled carbon nanotubes (S-MWCNTs) and polycyclic aromatic compounds (PAHs) has been reported. In the co-exposure condition, the adsorption of PAHs onto MWCNTs may reduce PAHs toxic effect. The objective of this study was to investigate the cytotoxicity of S-MWCNTs and benzo[a]pyrene (B[a]P) individually, and in combination in human lung cell lines (A549). The adsorption of B[a]P onto MWCNTs was measured spectrometrically. In vitro toxicity was assessed through cell viability, reactive oxygen species (ROS) generation, apoptosis, and 8-hydroxy-2'-deoxyguanosine (8-OHdG) generation experiments. The S-MWCNTs demonstrated cytotoxicity through the generation of ROS, apoptosis, and 8-OHdG in A549 cells. Co-exposure to S-MWCNTs and B[a]P demonstrated a significant reduction in ROS generation and apoptosis compared with the sum of their separate toxic effects at the same concentrations. Decreasing the bioavailability of B[a]P by MWCNT interaction is the probable reason for the antagonistic effects of the co-exposure condition. The findings of this study will contribute to a better understanding of the health effects of co-exposures to air pollutants and could be a starting point for modifying future health risk assessments.

DUSP26 regulates podocyte oxidative stress and fibrosis in a mouse model with diabetic nephropathy through the mediation of ROS

Diabetic nephropathy (DN) is a leading cause of renal failure worldwide. Unfortunately, the pathogenetic mechanism of DN is far from to be understood. Dual-specificity phosphatase 26 (DUSP26) is a member of the Dusp protein family, and is suggested to be involved in divers biological and pathological processes, such as cell growth, differentiation, inflammation and apoptosis. However, its role in the development of DN is still vague. In this study, we found that DUSP26 expression was increased in kidney of DN patients. Then, the wild type (DUSP26+/+) and gene knockout (DUSP26−/−) mice were used to further explore the effects of DUSP26 on DN development induced by streptozotocin (STZ). DUSP26 deficiency accelerated renal injury and dysfunction, as evidenced by the elevated glomerulosclerosis, reduced expression of Nephrin and promoted glomerular basement membrane thickness. In addition, STZ treatment resulted in reactive oxygen species (ROS) accumulation, H2O2 overproduction and superoxide dismutase (SOD) reduction in renal cortex or glomeruli of mice. The ROS production caused the activation of mitogen-activated protein kinase (MAPKs) signaling in kidney glomeruli of STZ-induced mice. These in vivo pathological processes were further confirmed in the differentiated podocytes stimulated by glucose (GLU). Intriguingly, we found that STZ-induced DN as mentioned above was further accelerated by DUSP26−/− in mice following STZ injection. Moreover, STZ-induced fibrosis in kidney glomeruli of DN mice was markedly prolonged in DUSP26-knockout mice through potentiating transforming growth factor-β1 (TGF-β1) expression. More importantly, reducing ROS generation could significantly abolish DUSP26 knockdown-exacerbated TGF-β1 expression and MAPKs activation, thereby protecting podocytes from GLU-induced podocyte injury. Thus, DUSP26-regulated DN development was largely dependent on ROS generation. Taken together, we concluded that DUSP26 might be a promising therapeutic target for developing effective treatments against DN progression.

Decrease of MLK4 prevents hepatocellular carcinoma (HCC) through reducing metastasis and inducing apoptosis regulated by ROS/MAPKs signaling

Hepatocellular carcinoma (HCC) results in large amounts of deaths each year worldwide. To develop more effective treatments for HCC, it is very necessary to define the molecular mechanisms in hepatocarcinogenesis. Mixed lineage kinase (MLK)-4 is a member of the MLK family of mitogen-activated protein kinase kinase kinases, and modulates different cellular responses. However, its role in the meditation of HCC progression remains unclear. In the study, we found that MLK4 was over-expressed in tumor samples of HCC patients. High MLK4 expression was significantly associated with shorter overall survival in HCC. Knockdown of MLK4 inhibited HCC cell proliferation and metastasis, which was partly through reducing matrix metalloproteinase (MMP)-13, MMP2, enhancer of zeste homolog 2 (EZH2) and Vimentin expressions. Apoptosis was significantly induced by MLK4 knockdown in HCC cells via decreasing Bcl-2 and increasing cleaved poly (ADP-ribose) polymerase (PARP), Caspase-7 and -3 expression levels. In addition, MLK4 silence led to a significant reactive oxygen species (ROS) production in liver cancer cells, accompanied with elevated expression of phosphorylated p38, c-Jun N-terminal kinase (JNK) and ERK1/2. Notably, reducing ROS generation and blocking MAPKs (p38/JNK/ERK1/2) signaling markedly abrogated MLK4 knockdown-induced apoptosis in HCC cells. Moreover, MLK4 silence-prevented metastasis was also rescued by scavenging ROS generation and repressing MAPKs pathway. In vivo, injection of MLK4 siRNA markedly inhibited liver tumor growth in xenograft models, and MLK4 knockdown reduced HCC lung metastasis. Together, our study indicated the essential function of MLK4 in HCC progression, providing crucial therapeutic hypothesis for the prevention of hepatocellular carcinoma.

YiQiFuMai Powder Injection Attenuates Coronary Artery Ligation-Induced Heart Failure Through Improving Mitochondrial Function via Regulating ROS Generation and CaMKII Signaling Pathways.

The YiQiFuMai powder injection (YQFM), a traditional Chinese medicine (TCM) prescription re-developed based on Sheng-Mai-San, is widely applied for the treatment of cardiovascular diseases. However, its potential molecular mechanism remains obscure. The present study was designed to observe the effects of YQFM and underlying mechanisms on coronary artery ligation (CAL)-induced heart failure (HF) and cell hypoxia of 24 h oxygen-glucose deprivation (OGD) in neonatal rat ventricular myocytes (NRVMs). HF was induced by permanent CAL for 2 weeks in ICR mice. The results demonstrated that YQFM significantly attenuated CAL-induced HF via improving the cardiac function, cardiac systolic function, cardiac structure impairment, cardiac histological features and fibrosis. YQFM markedly attenuated mitochondrial dysfunction through improving mitochondrial morphology, increasing mitochondria membrane potential (Δψm), mitochondrial ROS generation and expression of Mitofusin-2 (Mfn2), meanwhile, decreasing phosphorylation of dynamin-related protein 1 (p-Drp1). Mechanistically, YQFM could significantly decrease the expression of isoforms of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit NADPH oxidase 2 (NOX2), p67phox and NADPH oxidase 4 (NOX4), ultimately reducing reactive oxygen species (ROS) generation. In addition, YQFM could down-regulate expression of calcium voltage-gated channel subunit α1C (CACNA1C) and phosphorylation of calmodulin dependent protein kinase II (p-CaMKII). These results suggest that YQFM ameliorates mitochondrial function in HF mice, partially through inhibiting ROS generation and CaMKII signaling pathways. Therefore, the present study provided scientific evidence for the underlying mechanism of YQFM.

Ilexgenin A inhibits mitochondrial fission and promote Drp1 degradation by Nrf2-induced PSMB5 in endothelial cells.

Atherosclerosis (AS) is one of important events involving in the pathological process of coronary artery disease. Many traditional Chinese medicines have been widely used for the treatment of AS. Previous studies have demonstrated that Ilexgenin A (IA) obtained from Ilex hainanensis Merr. could improve AS development. However, its underlying mechanism is still unknown. This study was conducted to explore the possible targets and mechanisms involving in the anti-atheroclerosis effect of IA. The results showed IA significantly promoted NO production, reduced reactive oxygen species (ROS) generation, and inflammatory cytokine production induced by palmitate (PA) in endothelial cells, demonstrating IA could improve endothelial dysfunction. Meanwhile, IA dramatically inhibited dynamin-related protein 1 (Drp1) expression and mitochondrial fission induced by PA whereas proteasome inhibitor epoxomicin attenuated its effect on Drp1 expression, indicating IA decreased Drp1 expression with regulation of proteasome. Furthermore, IA also could increase the expression of proteasome subunit beta type5 (PSMB5) and activate nuclear factor-like 2 (Nrf2). Nrf2 knockdown eliminated the induction effect of IA on PSMB5 expression while abrogated its inhibition on ROS generation and mitochondrial fission stimulated by PA. These results demonstrated that IA could promote PSMB5 expression in an Nrf2-dependent manner, resulting in the suppression of mitochondrial fission, and thus improve endothelial dysfunction. These findings laid a foundation to the future development of IA as an agent to the prevention and treatment of AS.

Atorvastatin inhibits pro-inflammatory actions of aldosterone in vascular smooth muscle cells by reducing oxidative stress

Vascular inflammatory responses play an important role in several cardiovascular diseases. Of the many pro-inflammatory vasoactive factors implicated in this process, is aldosterone, an important mediator of vascular oxidative stress. Statins, such as atorvastatin, are cholesterol-lowering drugs that have pleiotropic actions, including anti-oxidant properties independently of their cholesterol-lowering effect. This study investigated whether atorvastatin prevents aldosterone-induced VSMC inflammation by reducing reactive oxygen species (ROS) production. Vascular smooth muscle cells (VSMC) from WKY rats were treated with 1 μM atorvastatin for 60 min or for 72 h prior to aldosterone (10-7 mol/L) stimulation. Atorvastatin inhibited Rac1/2 and p47phox translocation from the cytosol to the membrane, as well as reduced aldosterone-induced ROS production. Atorvastatin also attenuated aldosterone-induced vascular inflammation and macrophage adhesion to VSMC. Similarly EHT1864, a Rac1/2 inhibitor, and tiron, ROS scavenger, reduced macrophage adhesion. Through its inhibitory effects on Rac1/2 activation and ROS production, atorvastatin reduces vascular ROS generation and inhibits VSMC inflammation. Our data suggest that in conditions associated with aldosterone-induced vascular damage, statins may have vasoprotective effects by inhibiting oxidative stress and inflammation.

Effects of high glucose induced primary cardiomyocytes injury on necroptosis and the related mechanism

To observe whether necroptosis was happened in high glucose (HG) - induced primary cardiomyocytes injury and to investigate the likely mechanism. The primary cultured cardiomyocytes were divided into 4 groups (n=9): control group (the cardiomyocytes were incubated with 5.5 mmol/L glucose for 48 h), HG group (the cardiomyocytes were incubated with 30 mmol/L glucose for 48 h), HG + necrostatin-1 (Nec-1) group (the cardiomyocytes was co-incubated with necroptosis inhibitor Nec-1 at 100 μmol/L and HG for 48 h) and hypertonic pressure group (HPG, the cardiomyocytes was co-incubated with 5.5 mmol/L glucose and 24.5 mmol/L mannitol for 48 h). Cell viability was measured by MTT method, reactive oxygen species (ROS) generation was measured by DHE staining. The levels of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β) were tested by ELISA method. The mRNA and protein expressions of necroptosis related genes receptor interacting serine/threonine protein kinase 1 (RIP1), RIP3, mixed lineage kinase domain-like protein (MLKL) were tested by quantitative real-time PCR and Western blot. The results showed HG intervention decreased cardiomyocytes viability, increased ROS generation, up-regulated the levels of TNF-α, IL-6 and IL-1β, increased RIP1, RIP3, MLKL expressions at mRNA and protein levels. Nec-1 treatment attenuated HG-induced increased cardiomyocytes viability, reduced ROS generation, down-regulated the levels of TNF-α, IL-6 and IL-1β, decreased RIP1, RIP3, MLKL expressions at mRNA and protein levels. Necroptosis was happened in high glucose-induced primary cardiomyocytes injury. Inhibition of necroptosis can reduce high glucose-induced cardiomyocytes damage, may be related to inhibition of oxidative stress and depression of inflammative factors releasing.

Dual-function of Baicalin in nsPEFs-treated Hepatocytes and Hepatocellular Carcinoma cells for Different Death Pathway and Mitochondrial Response.

Nanosecond pulsed electric fields (nsPEFs) is emerged as a potential curative modality to ablate hepatocellular carcinoma (HCC). The application of local ablation is usually limited by insufficiency of liver function. While baicalin, a flavonoid isolated from Scutellaria baicalensis Georgi, has been proven to possess both anti-tumor and protective effects. Our study aimed to estimate different responses of hepatic cancer cells and hepatocytes to the combination of nsPEFs and baicalin. Cell viability, apoptosis and necrosis, mitochondrial transmembrane potential (MTP) and reactive oxygen species (ROS) were examined by CCK-8, FCM, JC-1 and fluorescent probe, respectively. After treatment by nsPEFs, most hepatocytes died by apoptosis, nevertheless, nearly all cancer cells were killed through necrosis. Low concentration of baicalin synergically enhanced nsPEFs-induced suppression and necrosis of HCC cells, nevertheless, the application of baicalin protected normal hepatocytes from the injury caused by nsPEFs, owing to elevating mitochondrial transmembrane potential and reducing ROS generation. Our work provided an advantageous therapy for HCC through the enhanced combination treatment of nsPEFs and baicalin, with which could improve the tumor-ablation effect and alleviate the injury of hepatic tissues simultaneously.

A tannic acid-modified fluoride pre-treated Mg-Zn-Y-Nd alloy with antioxidant and platelet-repellent functionalities for vascular stent application.

Vascular stent interventional therapy, as a regular and effective therapy, has been widely used to treat coronary artery diseases. However, adverse events occur frequently after stent intervention, especially restenosis and late stent thrombosis. The targeted implanting site will suffer from severe atherosclerosis, which is considered as a chronic inflammatory disease. Meanwhile, with the over-expanding use of endovascular mechanical intervention, vascular injury has become an increasingly common issue. Lesions and newly induced vascular injury result in inflammatory and oxidative stress; meanwhile, activated macrophages and granulocytes generate high levels of reactive oxygen species (ROS), contributing to endothelial dysfunction and neointima hyperplasia. Therefore, attenuating oxidative stress and reducing ROS generation in the inflammatory response represent reasonable strategies to inhibit intimal hyperplasia and restenosis. Herein, we have developed a multifunctional surface for the MgZnYNd alloy with tannic acid (TA) coating, and the pH dependence of the coating deposition is also demonstrated. The phenolic hydroxyl groups on the coatings endow the modified surface with excellent antioxidant functions. We found that the coating can be recycled, and the scavenging activity hardly weakened within five cycles. Also, the TA coating has a promising strong antioxidant activity as it shows a radical scavenging activity over 80% in long term. Moreover, the TA coating possesses platelet-repellent capability. No significant inflammatory response was observed for the TA modified sample in the rat subcutaneous implantation test. Combining these performances, we envision that the vascular stent modified with TA coating can have great potential in various applications by virtue of its simplicity and effectiveness.

PERK/eIF-2α/CHOP Pathway Dependent ROS Generation Mediates Butein-induced Non-small-cell Lung Cancer Apoptosis and G2/M Phase Arrest.

Butein, a member of the chalcone family, is a potent anticarcinogen against multiple cancers, but its specific anti-NSCLC mechanism remains unknown. The present study examined the effects of butein treatment on NSCLC cell lines and NSCLC xenografts. Butein markedly decreased NSCLC cell viability; inhibited cell adhesion, migration, invasion, and colony forming ability; and induced cell apoptosis and G2/M phase arrest in NSCLC cells. Moreover, butein significantly inhibited PC-9 xenograft growth. Both in vivo and in vitro studies verified that butein exerted anti-NSCLC effect through activating endoplasmic reticulum (ER) stress-dependent reactive oxygen species (ROS) generation. These pro-apoptotic effects were reversed by the use of 4- phenylbutyric acid (4-PBA), CHOP siRNA, N-acetyl-L-cysteine (NAC) and Z-VAD-FMK (z-VAD) in vitro. Moreover, inhibition of ER stress markedly reduced ROS generation. In addition, in vivo studies further confirmed that inhibition of ER stress or oxidative stress partially abolished the butein-induced inhibition of tumor growth. Therefore, butein is a potential therapeutic agent for NSCLC, and its anticarcinogenic action might be mediated by ER stress-dependent ROS generation and the apoptosis pathway.

SIRT3 Sumoylation Contributes to Chemoresistance in AML

Acute myeloid leukemia (AML) is a clonal disease originated from a rare population of malignant hematopoietic cells, called leukemic stem cells (LSCs), which is not only often resistant to standard chemotherapies, but also the major cause of relapse and eventual death of AML patients. The five-year survival of AML keeps as low as 27% for the last few decades. LSCs possess unique metabolism profiles such as higher rates of oxidative phosphorylation, and dependence on fatty acid oxidation for survival, which is distinct from normal hematopoietic cells, and, as a consequence, relatively low level of reactive oxygen species (ROS), a critical regulator for stemness maintenance. Therefore, targeting mitochondrial metabolism, especially ROS, may be a promising strategy to improve chemotherapy outcome for AML.We have previously found in hepatocarcinoma cells that SUMOylation is one of the important post-translational modifications for a variety of cellular proteins, and is capable of regulating the enzymatic activity of some key mitochondrial enzymes involved in the metabolic control, one example of which is SIRT3, a NAD+-dependent protein deacetylase. SIRT3 is reported to influence cellular metabolism and downregulate ROS generation by deacetylating mitochondrial anti-oxidant enzymes. The targets of SIRT3 include superoxide dismutase 2 (SOD2), manganese superoxide dismutase (MnSOD) and isocitrate dehydrogenase 2 (IDH2), which have been shown closely related to leukemogenesis. Since sophisticated regulation of ROS production is required for the maintenance of LSCs, we reproduced SUMOylation of SIRT3, and investigated its role in the mitochondrial metabolism in AML. In fact, SIRT3 SUMOylation at lysine 288 was also found in AML cells.To reveal the consequences of SIRT3 SUMOylation in AML, we constructed a plasmid expressing SIRT3-K288R that fails to be SUMOylated in AML cells. As a result, AML cells expressing SIRT3-K288R protected AML cells from as shown by apoptotic assays and quantitation of activated caspase 3 via reduction of not only total but also mitochondrial ROS production under chemotherapeutic agent-induced cell death comparing to those transfected with vector or overexpressing wild type SIRT3.To further investigate the role of SIRT3 de-SUMOylation in AML, we examined the influence of mitochondrial metabolism and anti-oxidant enzymes by SIRT3-K288R. SIRT3-K288R significantly downregulated the acetylation of mitochondrial anti-oxidant enzymes, such as SOD2, leading to decreased NADP/NADPH ratio and increased GSH/GSSG ratio. SIRT3 de-SUMOylation enhanced OCR but impaired ECAR under both basic and cytarabine treated conditions. We analyzed 18 primary AML samples to evaluate the correlation among SIRT3 SUMOylation, ROS level and chemoresistance. As we expected, low level of SIRT3 SUMOylation correlates with low cellular ROS level in both bulk AML and CD34+CD38- AML stem cells, and less sensitivity to cytarabine.Furthermore, MV4-11 cells bearing control vector, wild type SIRT3 or SIRT3-K288R were engrafted in NSG mice. Cytarabine was administered to the xenografts to evaluate the chemoresistance in these cell line-derived xenograft (CDX) mouse models. Consistent to the in vitro data, SIRT3-K288R reduced total and mitochondrial ROS in vivo, resulted in enhanced leukemogenesis and impaired survival.Taken together, our study showed that SIRT3 can be SUMOylated in AML. De-SUMOylation enhances SIRT3 deacetylase activity, and contribute to the chemoresistance of AML cells via altered mitochondrial metabolism and reduced ROS generation. Thus, SIRT3 and its de-SUMOylase can be utilized as potential therapeutic targets to improve AML chemotherapy. DisclosuresNo relevant conflicts of interest to declare.