Protein Levels Of Antioxidant Enzymes Research Articles

Therapeutic potential of salidroside in preserving rat cochlea organ of corti from gentamicin-induced injury through modulation of NRF2 signaling and GSK3β/NF-κB pathway.

Salidroside (SAL) is a phenol glycoside compound found in plants of the Rhodiola genus which has natural antioxidant and free radical scavenging properties. SAL are able to protect against manganese-induced ototoxicity. However, the molecular mechanism by which SAL reduces levels of reactive oxygen species (ROS) is unclear. Here, we established an in vitro gentamicin (GM) ototoxicity model to observe the protective effect of SAL on GM-induced hair cells (HC) damage. Cochlear explants of postnatal day 4 rats were obtained and randomly divided into six groups: two model groups (treatment with 0.2 mM or 0.4 mM GM for 24 h); two 400 μmol/L SAL-pretreated groups pretreatment with SAL for 3 h followed by GM treatment (0.2 mM or 0.4 mM) for 24 h; 400 μmol/L SAL group (treatment with SAL for 24 h); control group (normal cultured cochlear explants). The protective effects of SAL on GM-induced HC damage, and on mRNA and protein levels of antioxidant enzymes were observed. HC loss occurred after 24 h of GM treatment. Pretreatment with SAL significantly reduced GM-induced OHC loss. In cochlear tissues, mRNA and protein levels of NRF2 and HO-1 were enhanced in the GM alone group compared with the SAL pretreatment GM treatment group. SAL may protect against GM-induced ototoxicity by regulating the antioxidant defense system of cochlear tissues; SAL can activate NRF2/HO-1 signaling, inhibit NF-κB activation, activate AKT, and increase inhibitory phosphorylation of GSK3β to decrease GSK3 activity, all of which exert antioxidant effects.

Recombinant human brain natriuretic peptide attenuates ischemic brain injury in mice by inhibiting oxidative stress and cell apoptosis via activation of PI3K/AKT/Nrf2/HO-1 pathway.

Ischemic stroke followed by cerebral artery occlusion is a main cause of chronic disability worldwide. Recombinant human brain natriuretic peptide (rhBNP) has been reported to alleviate sepsis-induced cognitive dysfunction and brain I/R injury. However, the function and molecular mechanisms of rhBNP in ischemic brain injury have not been clarified. For establishment of an animal model of ischemic brain injury, C57BL/6 mice were treated with middle cerebral artery occlusion (MCAO) surgery for 1h and reperfusion for 24h. After subcutaneous injection of rhBNP into model mice, neurologic deficits were assessed by evaluating behavior of mice according to Longa scoring system, and TTC staining was utilized to determine the brain infarct size of mice. The levels of oxidative stress markers, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA), were detected in hippocampal tissues of mice by corresponding kits. Cell apoptosis in hippocampus tissues was examined by TUNEL staining. Protein levels of antioxidant enzymes (HO-1 and NQO1) in cerebral cortex, apoptotic markers (Bax, Bcl-2, and cleaved caspase), and PI3K/AKT pathway-associated factors in hippocampus were tested by western blot analysis. The results revealed that injection of rhBNP decreased neurologic deficit scores, the percent of brain water content, and infarct volume. Additionally, rhBNP downregulated MDA level, upregulated the levels of SOD, CAT, and GSH in hippocampus of mice, and increased protein levels of HO-1 and NQO1 in the cortex. Cell apoptosis in hippocampus tissues of model mice was inhibited by rhBNP which was shown as the reduced TUNEL-positive cells, the decreased Bax, cleaved caspase-3, and cleaved caspase-9 protein levels, and the enhanced Bcl-2 protein level. In addition, rhBNP treatment activated the PI3K/AKT signaling pathway and upregulated the protein levels of HO-1 and NRF2. Overall, rhBNP activates the PI3K/AKT/HO-1/NRF2 pathway to attenuate ischemic brain injury in mice after MCAO by suppression of cell apoptosis and oxidative stress.

Effects of Leptin and Body Weight on Inflammation and Knee Osteoarthritis Phenotypes in Female Rats.

Leptin is a proinflammatory adipokine that contributes to obesity-associated osteoarthritis (OA), especially in women. However, the extent to which leptin causes knee OA separate from the effect of increased body weight is not clear. We hypothesized that leptin is necessary to induce knee OA in obese female rats but not sufficient to induce knee OA in lean rats lacking systemic metabolic inflammation. The effect of obesity without leptin signaling was modeled by comparing female lean Zucker rats to pair fed obese Zucker rats, which possess mutant fa alleles of the leptin receptor gene. The effect of leptin without obesity was modeled in female F344BN F1 hybrid rats by systemically administering recombinant rat leptin versus saline for 23 weeks via osmotic pumps. Primary OA outcomes included cartilage histopathology and subchondral bone micro-computed tomography. Secondary outcomes included targeted cartilage proteomics, serum inflammation, and synovial fluid inflammation following an acute intra-articular challenge with interleukin-1β (IL-1β). Compared to lean Zucker rats, obese Zucker rats developed more severe tibial osteophytes and focal cartilage lesions in the medial tibial plateau, with modest changes in proximal tibial epiphysis trabecular bone structure. In contrast, exogenous leptin treatment, which increased plasma leptin sixfold without altering body weight, caused mild generalized cartilage fibrillation and reduced Safranin O staining compared to vehicle-treated animals. Leptin also significantly increased subchondral and trabecular bone volume and bone mineral density in the proximal tibia. Cartilage metabolic and antioxidant enzyme protein levels were substantially elevated with leptin deficiency and minimally suppressed with leptin treatment. In contrast, leptin treatment induced greater changes in systemic and local inflammatory mediators compared to leptin receptor deficiency, including reduced serum IL-6 and increased synovial fluid IL-1β. In conclusion, rat models that separately elevate leptin or body weight develop distinct OA-associated phenotypes, revealing how obesity increases OA pathology through both leptin-dependent and independent pathways. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Effects of salt and stress on blood pressure parameters and antioxidant enzyme function in the heart and aorta of borderline hypertensive rats.

What is the central question of this study? Although the involvement of reactive oxidative species in triggering hypertension has been documented, there are no data about the role of antioxidant enzymes in the heart and aorta of borderline hypertensive rats kept in baseline conditions or exposed to high salt with or without repeated stress. What is the main finding and its importance? In borderline hypertensive rats, high salt intake and stress contribute significantly to increase blood pressure and antioxidative defence in the aorta but decrease it in the heart. Elucidating the early changes that accompany elevated blood pressure could provide new therapeutical venues for prevention and treatment of the condition. Hypertension and its complications are a leading cause of death in the human population. Several factors can contribute to development of hypertension, such as genetic predisposition, high salt intake and environmental stressors, underlying oxidative stress as one of its key trademarks. We studied the effects of increased salt intake and chronic stress on blood pressure parameters and the activity and protein levels of antioxidant enzymes in the heart and aorta of borderline hypertensive rats (BHRs) with genetic susceptibility to hypertension. All animals were randomized into four groups: (1) Wistar rats kept in baseline conditions; (2) BHRs kept in baseline conditions; (3) BHRs drinking 0.9% saline solution; and (4) BHRs drinking 0.9% saline solution and exposed to repeated heterotypic stress. The BHRs exhibited significantly higher blood pressure, mitochondrial superoxide dismutase (SOD2) and catalase (CAT) protein levels and lower glutathione peroxidase (GPx) and glutathione reductase (GR) activities in the aorta, followed by lower CAT and GPx protein levels and higher CAT and GR activities in the heart, compared with normotensive Wistar rats. In the BHR aorta, high salt intake elevated CAT and GPx activities, and when combined with stress it increased GPx and GR activities. In BHR hearts, high salt intake provoked lower CAT activity. Adding repeated stress to salt treatment further decreased CAT activity, in addition to Cu2+ -Zn2+ superoxide dismutase (SOD1) and GR activities. The protein level of CAT was lower, whereas SOD2 and GPx increased. Overall, our results suggest that BHR hearts are better adapted to oxidative pressure, compared with the aorta, when exposed to salt and stress.

Oligonol ameliorates liver function and brain function in the 5 × FAD mouse model: transcriptional and cellular analysis.

Alzheimer's disease (AD) is a common neurodegenerative disease worldwide and is accompanied by memory deficits, personality changes, anxiety, depression, and social difficulties. For treatment of AD, many researchers have attempted to find medicinal resources with high effectiveness and without side effects. Oligonol is a low molecular weight polypeptide derived from lychee fruit extract. We investigated the effects of oligonol in 5 × FAD transgenic AD mice, which developed severe amyloid pathology, through behavioral tests (Barnes maze, marble burying, and nestle shredding) and molecular experiments. Oligonol treatment attenuated blood glucose levels and increased the antioxidant response in the livers of 5 × FAD mice. Moreover, the behavioral score data showed improvements in anxiety, depressive behavior, and cognitive impairment following a 2-month course of orally administered oligonol. Oligonol treatment not only altered the circulating levels of cytokines and adipokines in 5 × FAD mice, but also significantly enhanced the mRNA and protein levels of antioxidant enzymes and synaptic plasticity in the brain cortex and hippocampus. Therefore, we highlight the therapeutic potential of oligonol to attenuate neuropsychiatric problems and improve memory deficits in the early stage of AD.

Puerarin induces Nrf2 as a cytoprotective mechanism to prevent cadmium-induced autophagy inhibition and NLRP3 inflammasome activation in AML12 hepatic cells

Liver is the main target organ of cadmium (Cd) toxicity and puerarin (PU) has been shown to prevent Cd-induced hepatic cell damage via its antioxidant activity. Nrf2 acts as a critical regulator of cellular defense against various oxidative insults, but its role in the protection of PU against Cd-induced hepatic damage has not yet been clarified. Hereby, this study was designed to investigate the underlying mechanism using mouse hepatocyte line AML-12. Data firstly showed that Cd-inhibited Nrf2 pathway was markedly restored by PU treatment, assessed by Nrf2 nuclear translocation, protein levels of Keap1 and Nrf2 downstream target genes. Accordingly, Cd-reduced protein levels of antioxidant enzymes were significantly up-regulated by PU. Next, Nrf2 silencing cellular model was established to further elucidate the role of Nrf2 in the protection of PU against Cd-induced hepatic damage. Attenuation of Cd-induced autophagy inhibition and autophagosome accumulation by PU was remarkably countered by Nrf2 silencing. Moreover, alleviation of Cd-induced NLRP3 inflammasome activation by PU was distinctly prevented by Nrf2 knockdown, assessed by protein levels of NLRP3 inflammosome complex and downstream IL-18 and IL-1β production. Collectively, our data suggest that PU restores Cd-induced Nrf2 inhibition to prevent autophagy inhibition and NLRP3 inflammasome activation, providing novel insights into the protection of PU against Cd-induced hepatic cell damage.

Common Cellular Events Implicated in the Regulation of Cold Stress Tolerance and Soft Rot Resistance Induced by Metabolites of Pseudomonas Aeruginosa in Phalaenopsis Orchids

Microbial metabolites induce diverse plant physiological responses. In this study, Pseudomonas aeruginosa strain Y1 was shown to produce metabolites exhibiting a high capacity for metal chelation and moderate reducing power activity. In Phalaenopsis orchids, treatments with Y1 metabolites (Y1M) increased the contents of carbohydrates and lignin and the activity of antioxidant enzymes and phenylalanine ammonia lyase (PAL). Y1M treatments increased the tolerance to cold stress (10°C) by reducing malondialdehyde (MDA) accumulation and electrolyte leakage in a 10°C growth environment and enhanced disease resistance against bacterial soft rot caused by Erwinia chrysanthemi. Protein analyses indicated that, in response to Y1M treatment, the protein levels of antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX); pathogenesis-related (PR) proteins, such as PR-2 and PR-3; and lipoxygenase 1 (LOX1) were increased in Phalaenopsis orchids. Transcriptome analyses indicated that Y1M increased transcription associated with the iron-deficient response mediated by miRNA, the regulation of reactive oxygen species (ROS) homeostasis, and Jasmonic acid (JA) biosynthesis/perception. Gene groups associated with the induced defense response, including cellular events of pattern-triggered immunity (PTI), hypersensitive response (HR), synthesis of the PR protein, and callose formation, were also increased by the Y1M treatments. Transcription factors involved in regulating the cold stress response, such as C-repeat binding factor 1 (CBF1), and cell strengthening, such as MYB26, also had increased expression. In summary, Y1M can activate cellular pathways implicated in regulating stress tolerance shared by cold stress and bacterial invasion.

Common Cellular Events Implicated in the Regulation of Cold Stress Tolerance and Soft Rot Resistance Induced by Metabolites of Pseudomonas Aeruginosa in Phalaenopsis Orchids

Microbial metabolites induce diverse plant physiological responses. In this study, Pseudomonas aeruginosa strain Y1 was shown to produce metabolites exhibiting a high capacity for metal chelation and moderate reducing power activity. In Phalaenopsis orchids, treatments with Y1 metabolites (Y1M) increased the contents of carbohydrates and lignin and the activity of antioxidant enzymes and phenylalanine ammonia lyase (PAL). Y1M treatments increased the tolerance to cold stress (10°C) by reducing malondialdehyde (MDA) accumulation and electrolyte leakage in a 10°C growth environment and enhanced disease resistance against bacterial soft rot caused by Erwinia chrysanthemi. Protein analyses indicated that, in response to Y1M treatment, the protein levels of antioxidant enzymes, such as catalase (CAT) and ascorbate peroxidase (APX); pathogenesis-related (PR) proteins, such as PR-2 and PR-3; and lipoxygenase 1 (LOX1) were increased in Phalaenopsis orchids. Transcriptome analyses indicated that Y1M increased transcription associated with the iron-deficient response mediated by miRNA, the regulation of reactive oxygen species (ROS) homeostasis, and Jasmonic acid (JA) biosynthesis/perception. Gene groups associated with the induced defense response, including cellular events of pattern-triggered immunity (PTI), hypersensitive response (HR), synthesis of the PR protein, and callose formation, were also increased by the Y1M treatments. Transcription factors involved in regulating the cold stress response, such as C-repeat binding factor 1 (CBF1), and cell strengthening, such as MYB26, also had increased expression. In summary, Y1M can activate cellular pathways implicated in regulating stress tolerance shared by cold stress and bacterial invasion.

Protective function on liver and proteomic analysis of the improvement mechanism of Sedum sarmentosum Bunge extract on nonalcoholic fatty liver disease in Nile tilapia

Nonalcoholic fatty liver disease (NAFLD) caused by high-fat diet (HFD) feeding in fish has greatly impacted the aquaculture industry in a negative way. In order to investigate the effect of Sedum sarmentosum Bunge (SSB) extract on liver function and differentially expressed protein (DEP) profiles in NAFLD, Nile tilapia NAFLD model was constructed. Indicators of liver functions, blood lipid levels, and levels of antioxidant enzymes were evaluated. LC-MS/MS analysis was employed to identify DEPs for exploring the potential mechanism underlying the protective effect of SSB against NAFLD. Parallel reaction monitoring (PRM) was performed to verify the results of proteomic analysis. Growth, hepatosomatic index, hepatocyte apoptosis, levels of liver function indicators (AST, ALT, LDH, and TBA), and levels of blood lipids (CHOL and TG) were increased, and the mRNA and protein levels of antioxidant enzymes (HL and CAT) were decreased in HFD-fed tilapia as compared to normal diet-fed tilapia; notably, treatment with SSB extract reversed these alterations. A total of 302 DEPs were identified in the liver tissues of HFD-fed tilapia in comparison with normal diet-fed tilapia, of which regulation of 78 DEPs were significantly reversed by SSB treatment. Kyoto Encyclopedia of Genes and Genomes (KEGG) and protein–protein interaction (PPI) analysis showed that the 302 DEPs were enriched in processes such as fatty acid biosynthesis, steroid biosynthesis, lipid metabolism, and apoptosis, which are associated with development of NAFLD. Furthermore, results of PRM validation showed that the expression ratios of nine proteins were in accordance with the results of proteomic analysis. Our study reveals that SSB extract has a hepatoprotective role in Nile tilapia with HFD-induced NAFLD, and the observed changes in the DEP profiles indicate that SSB exerts its protective effects via regulation of lipid metabolism, steroid biosynthesis, and apoptosis.

Inflammation and oxidative stress induced by lipid peroxidation metabolite 4-hydroxynonenal in human corneal epithelial cells.

Oxidative stress is widely known to be a major contributor in the pathogenesis of dry eye disease (DED). 4-Hydroxynonenal (4-HNE), a well-known byproduct frequently measured as an indicator of oxidative stress-induced lipid peroxidation, has been shown to be elevated in both human and murine corneal DED samples. This study aims to investigate if 4-HNE is responsible for the oxidative stress in human corneal epithelial cells (HCECs) and explores the underlying mechanism by which it confers its effects. SV40-immortalized HCECs were cultured in minimum essential media (MEM) with 1% penicillin/streptomycin and 10% fetal bovine serum. HCECs were exposed to media with or without 4-HNE and cell culture supernatants were collected at 4 and 24h. Cellular reactive oxygen species (ROS) measurement was performed using a 2',7'-dichlorofluorescein diacetate (DCFDA) assay kit according to the manufacturer's instructions. Protein levels of antioxidant enzymes copper/zinc superoxide dismutase 1 (SOD1) and NAD(P)H quinone dehydrogenase 1 (NQO1) were analyzed by Western blot. NF-κB activation and expression of IL-6 and IL-8 were measured using an NF-κB p65 Total SimpleStep ELISA Kit and Proteome Profiler Human Cytokine Array Kit. Cell viability was evaluated by LDH cytotoxicity assay. Treatment with 4-HNE decreased cell viability of HCECs. Band intensities corresponding to levels of ROS production showed a significant increase in ROS generation after treatment with 4-HNE. 4-HNE decreased SOD1 levels and upregulated NQO1 expression in HCECs. A significant increase in activation of NF-κB and production of pro-inflammatory cytokines IL-6 and IL-8 was observed after treatment with 4-HNE. Exposure to N-acetylcysteine (NAC), an antioxidant and ROS scavenger, antagonized the oxidative effects of 4-HNE on HCECs. 4-HNE induces oxidative stress in corneal epithelial cells by increasing levels of ROS generation and modifying the expression of antioxidant enzyme levels, decreasing cell viability of HCECs in vitro. This study demonstrates a potential pathway by which 4-HNE functions to confer its detrimental effects and provides a new therapeutic target for the treatment of DED.

Puerarin reverses cadmium-induced lysosomal dysfunction in primary rat proximal tubular cells via inhibiting Nrf2 pathway

Previous studies have shown that oxidative stress-induced inhibition of autophagy plays a pivotal role in cadmium (Cd)-mediated cytotoxicity in primary rat proximal tubular (rPT) cells. The objective of this study is to explore the protective effect of puerarin (PU), a potent antioxidant, on Cd-induced autophagy inhibition and oxidative stress in rPT cells. First, Cd-induced blockage of autophagic flux in rPT cells was obviously restored by PU treatment, evidenced by immunoblot analysis of autophagy marker proteins and tandem fluorescent-tagged LC3 method. Resultantly, Cd-induced autophagosome accumulation was significantly alleviated by PU treatment. Also, Cd-induced lysosomal alkalinization and impairment of lysosomal degradation capacity were obviously recovered by PU, demonstrating that PU can restore Cd-induced lysosomal dysfunction. Moreover, Cd-induced lysosomal membrane permeabilization (LMP) was effectively blocked by PU. Cd-stimulated Nrf2 nuclear translocation and subsequent elevated expression of Nrf2-downstream targets were significantly inhibited by PU treatment. Simultaneously, Cd-elevated protein levels of antioxidant enzymes and glutathione synthesis-related proteins in rPT cells were markedly downregulated by PU treatment. In conclusion, these observations indicate that PU alleviates Cd-induced cytotoxicity in rPT cells through restoring autophagy, blocking LMP and inhibiting Nrf2 pathway, which is intimately related with its antioxidant activity.

P 204 - Differences in antioxidant enzymes in tumour tissue and non-tumour adjacent tissue in colorectal cancer patients at different stages (III and IV)

Colorectal Cancer (CRC) is one of the leading causes of death by cancer worldwide; its high mortality rate is mainly attributable to metastases. Oxidative stress has been classically related to cancer due to the harmful effects of free radicals, both in their onset and in their evolution. Recent studies have revealed the influence of non-tumour adjacent tissue on the progression and metastasis of CRC. Based on this, we have studied the protein levels of antioxidant enzymes by western blot comparing samples of non-tumour adjacent tissue and tumour tissue of CRC patients in advanced stages (III and IV). In the results obtained, higher levels of antioxidant enzymes have been observed in the tumour tissue than in the non-tumour adjacent tissue, although these differences are shortened in stage IV, due to the fact that stage IV patients present a significant increase in levels of antioxidant enzymes in non-tumour adjacent tissue. In addition, higher levels of antioxidant enzymes have been observed in the non-tumour adjacent tissue of patients in IV stage than in III This study emphasizes the importance of non-tumour adjacent tissue as a prognostic factor in the evolution of CRC cancer patients.

IL‐6 modulates cardiac muscle proteostasis and anti‐oxidative capacity post‐burn

Heart failure is the number one cause of death in severely burned patients. Burn‐induced cardiac dysfunction includes increased cardiac work, tachycardia and increased energy expenditure. Burn injury induces a surge in catecholamine and cytokines levels that lasts up to 3 years post injury. While cardiac dysfunction has been associated with stimulation of the β‐adrenergic receptors (β‐ARs) by catecholamines, the role of inflammatory cytokines in the cardiac muscle function is still unclear. We have reported that burn injury alters the beta‐adrenergic signaling in the heart at 7 days post‐burn. In another study, we have shown that burn injury induces atrophy of the diaphragm muscle through activation of the IL‐6/JAK/Stat pathway.Male wild‐type and interleukin 6 knockout mice (IL‐6 KO) were subjected to a 30% total body surface area full‐thickness burn. Animals were sacrificed 10 days post injury. The hearts were isolated and western blotting performed to analyze the role of JAK/Stat signaling pathways and antioxidant enzymes in cardiac muscle proteostasis post‐burn.Burn injury significantly increases Stat‐3 phosphorylation at Ser 727 in the WT (p<0.05) but not in the IL‐6‐KO animals. Stat‐3 phosphorylation at tyrosine705 (Y705) was activated in the cardiac muscle of both the WT (p<0.05) and IL‐6 KO (p<0.05) mice post‐burn. At basal levels, p‐Stat‐3(Y705) was higher in the control IL‐6 KO than the control WT animals (p< 0.05). P‐Stat‐3 (Y705) levels were also higher in L‐6 KO burned animals compared to WT burned animals (p<0.01). The protein levels of antioxidant enzymes SOD‐2 and catalase were significantly decreased post‐burn in the WT (both p<0.05) but not in the IL‐6 KO animals.These data suggest that the molecular mechanisms regulating cardiac muscle proteostasis and anti‐oxidative capacity following burn injury are altered in the IL‐6‐KO mice supporting the role of IL‐6 as a critical mediator in these processes.Support or Funding InformationThis study was supported by grants from the National Institute of Health (P50‐GM60338, R01‐GM56687, and T32‐GM8256, NIH R01 GM 112936‐01, UL1TR000071), Shriners Hospitals for Children (71008, 71001 and 84080), and the Shriners Hospital for Children fellowship for AE (SHC 84202).

Olfactory Ensheathing Cell-Conditioned Medium Reverts Aβ25-35-Induced Oxidative Damage in SH-SY5Y Cells by Modulating the Mitochondria-Mediated Apoptotic Pathway.

Olfactory ensheathing cells (OECs) are a type of glia from the mammalian olfactory system, with neuroprotective and regenerative properties. β-Amyloid peptides are a major component of the senile plaques characteristic of the Alzheimer brain. The amyloid beta (Aβ) precursor protein is cleaved to amyloid peptides, and Aβ25-35 is regarded to be the functional domain of Aβ, responsible for its neurotoxic properties. It has been reported that Aβ25-35 triggers reactive oxygen species (ROS)-mediated oxidative damage, altering the structure and function of mitochondria, leading to the activation of the mitochondrial intrinsic apoptotic pathway. Our goal is to investigate the effects of OECs on the toxicity of aggregated Aβ25-35, in human neuroblastoma SH-SY5Y cells. For such purpose, SH-SY5Y cells were incubated with Aβ25-35 and OEC-conditioned medium (OECCM). OECCM promoted the cell viability and reduced the apoptosis, and decreased the intracellular ROS and the lipid peroxidation. In the presence of OECCM, mRNA and protein levels of antioxidant enzymes (SOD1 and SOD2) were upregulated. Concomitantly, OECCM decreased mRNA and the protein expression levels of cytochrome c, caspase-9, caspase-3, and Bax in SH-SY5Y cells, and increased mRNA and the protein expression level of Bcl-2. However, OECCM did not alter intracellular Ca2+ concentration in SH-SY5Y cells. Taken together, our data suggest that OECCM ameliorates Aβ25-35-induced oxidative damage in neuroblastoma SH-SY5Y cells by inhibiting the mitochondrial intrinsic pathway. These data provide new insights into the functional actions of OECCM on oxidative stress-induced cell damage.

Pharmacological targeting of mitochondrial reactive oxygen species counteracts diaphragm weakness in chronic heart failure.

Diaphragm muscle weakness in chronic heart failure (CHF) is caused by elevated oxidants and exacerbates breathing abnormalities, exercise intolerance, and dyspnea. However, the specific source of oxidants that cause diaphragm weakness is unknown. We examined whether mitochondrial reactive oxygen species (ROS) cause diaphragm weakness in CHF by testing the hypothesis that CHF animals treated with a mitochondria-targeted antioxidant have normal diaphragm function. Rats underwent CHF or sham surgery. Eight weeks after surgeries, we administered a mitochondrial-targeted antioxidant (MitoTEMPO; 1 mg·kg(-1)·day(-1)) or sterile saline (Vehicle). Left ventricular dysfunction (echocardiography) pre- and posttreatment and morphological abnormalities were consistent with the presence of CHF. CHF elicited a threefold (P < 0.05) increase in diaphragm mitochondrial H2O2 emission, decreased diaphragm glutathione content by 23%, and also depressed twitch and maximal tetanic force by ∼20% in Vehicle-treated animals compared with Sham (P < 0.05 for all comparisons). Diaphragm mitochondrial H2O2 emission, glutathione content, and twitch and maximal tetanic force were normal in CHF animals receiving MitoTEMPO. Neither CHF nor MitoTEMPO altered the diaphragm protein levels of antioxidant enzymes: superoxide dismutases (CuZn-SOD or MnSOD), glutathione peroxidase, and catalase. In both Vehicle and MitoTEMPO groups, CHF elicited a ∼30% increase in cytochrome c oxidase activity, whereas there were no changes in citrate synthase activity. Our data suggest that elevated mitochondrial H2O2 emission causes diaphragm weakness in CHF. Moreover, changes in protein levels of antioxidant enzymes or mitochondrial content do not seem to mediate the increase in mitochondria H2O2 emission in CHF and protective effects of MitoTEMPO.

리치 저분자 폴리페놀인 Oligonol의 Streptozotocin 투여 당뇨 쥐에서 산화적 스트레스와 관련된 간 손상에 미치는 영향

This study was conducted to examine whether or not oligonol, a low molecular weight polyphenol derived from lychee fruit, has an ameliorative effect on diabetes-induced oxidative stress-related hepatic damage in streptozotocin (STZ)-induced diabetic rats. Oligonol (10 or 20 mg/kg body weight; O10 or O20, respectively) was orally administered every day for 10 days to STZ-induced diabetic rats, and its effects were compared to vehicle-treated diabetic (Veh) and non-diabetic rats. Administration of 20 mg/kg of oligonol significantly decreased liver weight compared with the Veh group (P<0.05). Elevated levels of hepatic glucose, reactive oxygen species, peroxynitrite, and lipid peroxidation were detected in diabetic vehicle rats, whereas oligonol treatment significantly attenuated these levels (P<0.05). In diabetic vehicle rats, hepatic antioxidant enzyme protein levels decreased, whereas oligonol treatment showed significant elevated results. For inflammation-related protein expression, oligonol-treated groups showed insignificant reduction. Oligonol improved expression of proapoptotic protein caspase-3 in the liver of diabetic rats (P<0.05). In conclusion, these results provide important evidence that oligonol exhibits an inhibitory effect on oxidative stress and apoptosis-related protein expression as well as a hepato-protective effect against the development of diabetic complications in STZ-induced type 1 diabetic rats.

An antioxidant response is involved in resistance of Giardia duodenalis to albendazole.

Albendazole (ABZ) is a therapeutic benzimidazole used to treat giardiasis that targets β-tubulin. However, the molecular bases of ABZ resistance in Giardia duodenalis are not understood because β-tubulin in ABZ-resistant clones lacks mutations explaining drug resistance. In previous work we compared ABZ-resistant (1.35, 8, and 250 μM) and ABZ-susceptible clones by proteomic analysis and eight proteins involved in energy metabolism, cytoskeleton dynamics, and antioxidant response were found as differentially expressed among the clones. Since ABZ is converted into sulphoxide (ABZ-SO) and sulphone (ABZ-SOO) metabolites we measured the levels of these metabolites, the antioxidant enzymes and free thiols in the susceptible and resistant clones. Production of reactive oxygen species (ROS) and levels of ABZ-SO/ABZ-SOO induced by ABZ were determined by fluorescein diacetate-based fluorescence and liquid chromatography respectively. The mRNA and protein levels of antioxidant enzymes (NADH oxidase, peroxiredoxin 1a, superoxide dismutase and flavodiiron protein) in these clones were determined by RT-PCR and proteomic analysis. The intracellular sulfhydryl (R-SH) pool was quantified using dinitrobenzoic acid. The results showed that ABZ induced ROS accumulation in the ABZ-susceptible Giardia cultures but not in the resistant ones whilst the accumulation of ABZ-SO and ABZ-SOO was lower in all ABZ-resistant cultures. Consistent with these findings, all the antioxidant enzymes detected and analyzed were upregulated in ABZ-resistant clones. Likewise the R-SH pool increased concomitantly to the degree of ABZ-resistance. These results indicate an association between accumulation of ABZ metabolites and a pro-oxidant effect of ABZ in Giardia-susceptible clones. Furthermore the antioxidant response involving ROS-metabolizing enzymes and intracellular free thiols in ABZ-resistant parasites suggest that this response may contribute to overcome the pro-oxidant cytotoxicity of ABZ.

Cytokine and Antioxidant Regulation in the Intestine of the Gray Mouse Lemur (Microcebus murinus) During Torpor

During food shortages, the gray mouse lemur (Microcebus murinus) of Madagascar experiences daily torpor thereby reducing energy expenditures. The present study aimed to understand the impacts of torpor on the immune system and antioxidant response in the gut of these animals. This interaction may be of critical importance given the trade-off between the energetically costly immune response and the need to defend against pathogen entry during hypometabolism. The protein levels of cytokines and antioxidants were measured in the small intestine (duodenum, jejunum, and ileum) and large intestine of aroused and torpid lemurs. While there was a significant decrease of some pro-inflammatory cytokines (IL-6 and TNF-α) in the duodenum and jejunum during torpor as compared to aroused animals, there was no change in anti-inflammatory cytokines. We observed decreased levels of cytokines (IL-12p70 and M-CSF), and several chemokines (MCP-1 and MIP-2) but an increase in MIP-1α in the jejunum of the torpid animals. In addition, we evaluated antioxidant response by examining the protein levels of antioxidant enzymes and total antioxidant capacity provided by metabolites such as glutathione (and others). Our results indicated that levels of antioxidant enzymes did not change between torpor and aroused states, although antioxidant capacity was significantly higher in the ileum during torpor. These data suggest a suppression of the immune response, likely as an energy conservation measure, and a limited role of antioxidant defenses in supporting torpor in lemur intestine.

Melatonin attenuates intermittent hypoxia-induced lipid peroxidation and local inflammation in rat adrenal medulla.

Chronic intermittent hypoxia (CIH) induces lipid peroxidation and leads to cardiovascular dysfunction, in which impaired activities of the adrenal medulla are involved. This may be caused by CIH-induced injury in the adrenal medulla, for which the mechanism is currently undefined. We tested the hypothesis that melatonin ameliorates the CIH-induced lipid peroxidation, local inflammation and cellular injury in rat adrenal medulla. Adult Sprague–Dawley rats were exposed to air (normoxic control) or hypoxia mimicking a severe recurrent sleep apnoeic condition for 14 days. The injection of melatonin (10 mg/kg) or vehicle was given before the daily hypoxic treatment. We found that levels of malondialdehyde and nitrotyrosine were significantly increased in the vehicle-treated hypoxic group, when compared with the normoxic control or hypoxic group treated with melatonin. Also, the protein levels of antioxidant enzymes (superoxide dismutase (SOD)-1 and SOD-2) were significantly lowered in the hypoxic group treated with vehicle but not in the melatonin group. In addition, the level of macrophage infiltration and the expression of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6) and mediators (inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2)) were elevated in the vehicle-treated hypoxic group, but were significantly ameliorated by the melatonin treatment. Moreover, the amount of apoptotic cells in the hypoxic groups was significantly less in the melatonin-treated group. In conclusion, CIH-induced lipid peroxidation causes local inflammation and cellular injury in the adrenal medulla. The antioxidant and anti-inflammatory actions of melatonin are indicative of a protective agent against adrenal damage in patients with severe obstructive sleep apnea syndrome.

Oxidative Stress and DNA Lesions: The Role of 8-Oxoguanine Lesions in Trypanosoma cruzi Cell Viability

The main consequence of oxidative stress is the formation of DNA lesions, which can result in genomic instability and lead to cell death. Guanine is the base that is most susceptible to oxidation, due to its low redox potential, and 8-oxoguanine (8-oxoG) is the most common lesion. These characteristics make 8-oxoG a good cellular biomarker to indicate the extent of oxidative stress. If not repaired, 8-oxoG can pair with adenine and cause a G:C to T:A transversion. When 8-oxoG is inserted during DNA replication, it could generate double-strand breaks, which makes this lesion particularly deleterious. Trypanosoma cruzi needs to address various oxidative stress situations, such as the mammalian intracellular environment and the triatomine insect gut where it replicates. We focused on the MutT enzyme, which is responsible for removing 8-oxoG from the nucleotide pool. To investigate the importance of 8-oxoG during parasite infection of mammalian cells, we characterized the MutT gene in T. cruzi (TcMTH) and generated T. cruzi parasites heterologously expressing Escherichia coli MutT or overexpressing the TcMTH enzyme. In the epimastigote form, the recombinant and wild-type parasites displayed similar growth in normal conditions, but the MutT-expressing cells were more resistant to hydrogen peroxide treatment. The recombinant parasite also displayed significantly increased growth after 48 hours of infection in fibroblasts and macrophages when compared to wild-type cells, as well as increased parasitemia in Swiss mice. In addition, we demonstrated, using western blotting experiments, that MutT heterologous expression can influence the parasite antioxidant enzyme protein levels. These results indicate the importance of the 8-oxoG repair system for cell viability.