High Levels Of ROS Research Articles

Effect of lupeol on insulin resistance in adipose tissue by modulating the expression of insulin and inflammatory signaling molecules in high-fat diet and sucrose-fed diabetic rats

The prevalence of obesity and diabetes has increased globally as a result of lifestyle modifications including eating a high-fat diet and not exercising. The target tissues to insulin action are the key pathophysiological event contributing to the development of type 2 diabetes mellitus. The treatments for type 2 diabetes that are now accessible are ineffectual due to their unfavourable side effects. Hence, search drugs, from plant sources. Lupeol is widely present in various medicinal plants. It has been reported to elicit multitude of bioactivities including antilipidemic and antihyperglycemic activity. However, specific effect of Lupeol on insulin signaling molecules of adipose tissue remains unclear. Hence, the study aimed to assess the beneficial role of Lupeol on the expression of insulin‑signaling molecules in adipose tissue of high fat diet and sucrose-induced type‑2 diabetic rats. The oral effective dose of lupeol at a dose of 25 mg per kg body weight per day orally for 30 days is observed. Lupeol, being a powerful antioxidant agent, normalises hyperglycemia, dyslipidaemia, and hyperinsulinemia while also suppressing oxidative stress by scavenging high levels of ROS. It also enhances insulin signalling in type 2 diabetic rats in adipose tissues. Lupeol administration decreased the levels of pro-inflammatory cytokines, which may be due to lupeol's possible antioxidant and anti-inflammatory activities, and thus it promotes insulin sensitivity via altering pro-inflammatory signalling molecules in adipose tissue such as IL-6, TNF alpha, and NFkB. As a result of the current findings, it is concluded that lupoel possesses potent anti-diabetic characteristics and could be used as a phytomedicine for the treatment of type 2 diabetes.

POLG genotype influences degree of mitochondrial dysfunction in iPSC derived neural progenitors, but not the parent iPSC or derived glia

Diseases caused by POLG mutations are the most common form of mitochondrial diseases and associated with phenotypes of varying severity. Clinical studies have shown that patients with compound heterozygous POLG mutations have a lower survival rate than patients with homozygous mutations, but the molecular mechanisms behind this remain unexplored. Using an induced pluripotent stem cell (iPSC) model, we investigate differences between homozygous and compound heterozygous genotypes in different cell types, including patient-specific fibroblasts, iPSCs, and iPSC-derived neural stem cells (NSCs) and astrocytes. We found that compound heterozygous lines exhibited greater impairment of mitochondrial function in NSCs than homozygous NSCs, but not in fibroblasts, iPSCs, or astrocytes. Compared with homozygous NSCs, compound heterozygous NSCs exhibited more severe functional defects, including reduced ATP production, loss of mitochondrial DNA (mtDNA) copy number and complex I expression, disturbance of NAD+ metabolism, and higher ROS levels, which further led to cellular senescence and activation of mitophagy. RNA sequencing analysis revealed greater downregulation of mitochondrial and metabolic pathways, including the citric acid cycle and oxidative phosphorylation, in compound heterozygous NSCs. Our iPSC-based disease model can be widely used to understand the genotype-phenotype relationship of affected brain cells in mitochondrial diseases, and further drug discovery applications.

Manganese-Based Antioxidase-Inspired Biocatalysts with Axial Mn-N5 Sites and 2D d-π-Conjugated Networks for Rescuing Stem Cell Fate.

Constructing highly effective biocatalysts with controllable coordination geometry for eliminating reactive oxygen species (ROS) is extremely desirable but remains challenging for addressing the current bottlenecks in stem-cell-based therapeutics. Here, inspired by the coordination structure of manganese-based antioxidase, we report amanganese-coordinated polyphthalocyanine-based biocatalyst (Mn-PcBC) with axial Mn-N5 sites and 2D d-π-conjugated networks to serve as artificial antioxidase for rescuing stem cell fates. Owing to the unique chemical and electronic structures, the Mn-PcBC displays efficient, multifaceted, and robust ROS-scavenging activities, including the H2O2 and O2•-, which surpasses the by-far-reported Mn-based ROS-scavenging artificial antioxidases. Consequently, the Mn-PcBC provides efficient rescuing of the bioactivities and functionalities of stem cells in high ROS-level microenvironments via protecting the transcription of osteogenesis-related genes. This work not only offers essential insights into the crucial functions of axially coordinated Mn-N5 sites in ROS-scavenging but also proposes new strategies to create efficient artificial antioxidases for stem-cell therapies.

Deciphering the mechanism of fungal pathogen-induced disease-suppressive soil.

One model of a disease-suppressive soil predicts that the confrontation of plant with a phytopathogen can lead to the recruitment and accumulation of beneficial microorganisms. However, more information needs to be deciphered regarding which beneficial microbes become enriched, and how the disease suppression is achieved. Here, we conditioned soil by continuously growing eight generations of cucumber inoculated with Fusarium oxysporum f.sp. cucumerinum in a split-root system. Disease incidence was found to decrease gradually upon pathogen infection accompanied with higher quantity of reactive oxygen species (ROS mainly OH• ) in roots and accumulation of Bacillus and Sphingomonas. These key microbes were proven to protect the cucumber from pathogen infection by inducing high ROS level in the roots through enrichment of pathways, including a two-component system, a bacterial secretion system, and flagellar assembly revealed by metagenomics sequencing. Untargeted metabolomics analysis combined with invitro application assays suggested that threonic acid and lysine were pivotal to recruit Bacillus and Sphingomonas. Collectively, our study deciphered a 'cry for help' case, wherein cucumber releases particular compounds to enrich beneficial microbes that raise the ROS level of host to prevent pathogen attack. More importantly, this may be one of the fundamental mechanisms underpinning disease-suppressive soil formation.

Abstract 1386: Ag5 is highly potent, mitochondrially targeted agent with a differentiated mechanism of action that promises to be efficacious in solid cancers

Abstract Mitochondrial remodeling in cancer is important for tumorigenesis, metastasis and linked totreatment resistance and poor prognosis. Dysfunctional mitochondria are also driven by oncogenes (e.g. KRAS, MYC) resulting in an increased oxidation state triggering the antioxidant response in order to decrease ROS levels, and to trigger apoptosis when the oxidative stress cannot be overcome. So far, targeting cancer cell energy metabolism has been unsuccessful due to tumor evolution, low therapeutic index and redundancy of protective mechanisms. Taken together, the clinical sequelae of mitochondrial remodeling represent one of the largest areas of unmet need in cancer therapy. We are developing Ag5, a highly potent, mitochondrially targeted agent with a novel mechanism of action that promises to be efficacious in solid cancers. Ag5 selectively kills cancer cells by catalyzing the oxidation of thiol groups of members ofthese pathways, a rapid mechanism of action that can be reversed with ROS scavengers (e.g. NAC). As a consequence, Ag5 will preferentially kill cancer cells, but will spare normal cells due to their REDOX homeostasis. We characterized Ag5 efficacy with a range of in vitro viability assays and showed potency against a panel of established cancer cell lines with an IC50 in the low nM range, whereas Ag5 activity was significantly lower in non-malignant cells. Ag5 sensitivity was not only correlated with high ROS levels as measured by mitoSOX, but also with target protein oxidation (especially the mitochondrially expressed PRDX3), cardiolipin and cytochrome c release, thus highlighting the mitochondrial targeting of Ag5. Several well characterised gene mutations lead to alterations in mitochondrial antioxidant function which sensitise the tumors to Ag5, either by decreasing endogenous antioxidant synthesis or increasing reliance on antioxidants for cell survival. For example, ARID1A damaging mutations directly lead to decreased glutathione synthesis and are found in many solid cancers (e.g. NSCLC, CRC and clear cell ovarian cancers). Experimental data with pairs of ARID1A wild-type or KO cell lines showed strong sensitization to Ag5 activity when ARID1A is knocked out. Furthermore, Ag5 was shown to be effective in reducing tumor growth in KRAS G12C mutated NSCLC and other relevant cell lines in viability assays and an orthotopic in vivo model. Combination treatment with KRAS, SOS1 and SHP2 inhibitors demonstrated not only Ag5 synergy, but also superior efficacy when Ag5 was included over the combination of these inhibitors alone. In summary, Ag5 is a novel and innovative therapeutic candidate shown to be safe and effective in preclinical studies. Based on experimental data with clinically relevant mutations, we hypothesize that Ag5 is ideally investigated in enriched patient populations of lung cancerand other solid cancers. Citation Format: Martin Treder. Ag5 is highly potent, mitochondrially targeted agent with a differentiated mechanism of action that promises to be efficacious in solid cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1386.

Duplex Responsive Nanoplatform with Cascade Targeting for Atherosclerosis Photoacoustic Diagnosis and Multichannel Combination Therapy.

The culprits of atherosclerosis are endothelial damage, local disorders of lipid metabolism, and progressive inflammation. Early atherosclerosis is typically difficult to diagnose in time due to the lack of obvious symptoms, thus missing the best period of treatment. In this work, a π-conjugated polymer (PMeTPP-MBT) based on 3,6-bis(4-methylthiophen-2-yl)-2,5-bis(2-octyldodecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione is designed as a novel photoacoustic contrast agent. On this basis, an intelligent responsive theranostic nanoplatform (PA/ASePSD) combining astaxanthin and SS-31 peptide and loading with PMeTPP-MBT is developed. The high affinity between the dextran shell with the broken endothelial surface VCAM-1 and CD44 confers active targeting of PA/ASePSD to atherosclerotic lesions. High levels of ROS in the acidic plaque microenvironment act as an intelligent cascade switch to achieve controlled release of astaxanthin, SS-31 peptide, and PMeTPP-MBT for non-invasive photoacoustic diagnosis, as well as plaque inhibition mediated by anti-inflammation and multichannel regulation (including ABCA1, ABCG1, CD36, and LOX-1) of lipid metabolism. Both in vitro and in vivo evaluations confirm the impressive anti-atherosclerotic capability and the accurate photoacoustic diagnosis of PA/ASePSD nanoparticles, thus promising a candidate for early-stage atherosclerosis theranostics.

Rutin Protects Fibroblasts from UVA Radiation through Stimulation of Nrf2 Pathway

This study explores the photoprotective effects of rutin, a bioflavonoid found in some vegetables and fruits, against UVA-induced damage in human skin fibroblasts. Our results show that rutin increases cell viability and reduces the high levels of ROS generated by photo-oxidative stress (1 and 2 h of UVA exposure). These effects are related to rutin's ability to modulate the Nrf2 transcriptional pathway. Interestingly, activation of the Nrf2 signaling pathway results in an increase in reduced glutathione and Bcl2/Bax ratio, and the subsequent protection of mitochondrial respiratory capacity. These results demonstrate how rutin may play a potentially cytoprotective role against UVA-induced skin damage through a purely antiapoptotic mechanism.

Chemical Composition of Hazelnut Skin Food Waste and Protective Role against Advanced Glycation End-Products (AGEs) Damage in THP-1-Derived Macrophages.

Glycation and the accumulation of advanced glycation end-products (AGEs) are known to occur during aging, diabetes and neurodegenerative diseases. Increased glucose or methylglyoxal (MGO) levels in the blood of diabetic patients result in increased AGEs. A diet rich in bioactive food compounds, like polyphenols, has a protective effect. The aim of this work is to evaluate the capacity of hazelnut skin polyphenolic extract to protect THP-1-macrophages from damage induced by AGEs. The main polyphenolic subclass was identified and quantified by means of HPLC/MS and the Folin-Ciocalteu method. AGEs derived from incubation of bovine serum albumin (BSA) and MGO were characterized by fluorescence. Cell viability measurement was performed to evaluate the cytotoxic effect of the polyphenolic extract in macrophages. Reactive oxygen species' (ROS) production was assessed by the H2-DCF-DA assay, the inflammatory response by real-time PCR for gene expression, and the ELISA assay for protein quantification. We have shown that the polyphenolic extract protected cell viability from damage induced by AGEs. After treatment with AGEs, macrophages expressed high levels of pro-inflammatory cytokines and ROS, whereas in co-treatment with polyphenol extract there was a reduction in either case. Our study suggests that hazelnut skin polyphenol-rich extracts have positive effects and could be further investigated for nutraceutical applications.

Sirt3-dependent regulation of mitochondrial oxidative stress and apoptosis contributes to the dysfunction of pancreatic islets after severe burns.

Severe burns are often complicated with hyperglycemia caused by mitochondrial oxidative stress-related pancreatic islet dysfunction. Silent information regulator of transcription 3 (Sirt3) can regulate mitochondrial oxidative stress. However, the role and mechanism of Sirt3 on islet function after severe burns remain unclear. Therefore, this study aimed to investigate whether Sirt3 played a role in both mitochondrial oxidative stress in islets and mediating islet function post severe burns. A mouse model of 30% total body surface area full-thickness burn and an in vitro MIN6 cell hypoxia model were established. Sirt3 KO mice were used to demonstrate further the role of Sirt3 in maintaining redox homeostasis and regulating islet function. Fasting blood glucose and glucose-stimulated insulin secretion (GSIS) were detected to assess the islet function. The levels of mitochondrial ROS and deacetylation, and the activities of Mn-SOD and IDH2 were measured to evaluate oxidative stress. The mitochondrial membrane potential (MMP)was detected and the apoptosis rate measured. In vitro MIN6 cells, the hypoxia treatment significantly reduced Sirt3 expression, resulting in increased deacetylation of Mn-SOD and IDH2, which further led to a higher level of mitochondrial ROS. In addition, hypoxia reduced MMP and increased apoptosis rate, which impaired GSIS eventually. Knockdown of Sirt3 caused similar alterations. The hypoxia-induced high level of mitochondrial ROS and apoptosis and impaired GSIS could be reversed by overexpression of Sirt3. Similarly, after severe burns, the expression of Sirt3 in islets decreased significantly with a high level of deacetylation of Mn-SOD, IDH2, mitochondrial ROS and apoptosis, and islet dysfunction. Oxidative stress and apoptosis also occurred in islets of Sirt3 KO mice, accompanied by islet dysfunction. Sirt3 and downstream signalling are critical in modulating the islet function post severe burns by regulating mitochondrial oxidative stress and apoptosis.

BMP4 aggravates mitochondrial dysfunction of HRMECs

Mitochondria are important places for the oxidative phosphorylation of glucose and the maintenance of cell oxidation and antioxidant stability. However, mitochondrial dysfunction causes cell dysfunction. Meanwhile, retinal vascular endothelial cell dysfunction may cause vascular inflammation, hemorrhage, angiogenesis, and other manifestations. Our previous studies have shown that Bone morphogenetic protein 4 (BMP4) is an important target for the treatment of retinal neovascularization, but the mechanism remains unclear. Therefore, our study aims to observe the effects of BMP4 on vascular endothelial cells and hopes to provide a new target for diabetic retinopathy. 4-Hydroxynonenal (4HNE), a kind of lipid peroxide, was used to induce the oxidative stress model. Human retinal microvascular endothelial cells (HRMECs) were randomly divided into control, 4HNE, negative control, and siBMP4 groups. Si-BMP4 significantly reduced leukocyte adhesion and 4HNE-induced high ROS level and restored the mitochondrial membrane potential and OCR. This indicates that BMP4 plays an important role in inducing leukocyte adhesion, oxidative stress, and mitochondrial dysfunction. The relationship between BMP4 and retinal vascular endothelial cell dysfunction is preliminarily confirmed by this study. Mitochondrial dysfunction and oxidative stress may be involved in BMP4-mediated retinal vascular endothelial cell dysfunction.

Role of profilin-1 in vasculopathy induced by advanced glycation end products (AGEs)

AimsTo construct a simple and feasible rat model to mimic diabetic vasculopathy by chronic injection of advanced glycation end products (AGEs) and further determine the role of profilin-1 in vasculopathy in AGE-injection rats. MethodsSprague-Dawley rats were injected with AGEs-BSA (25 mg/kg/day) for 0, 20, 30, 40, and 60 days by caudal vein. Then, the morphological changes in the aorta, heart, and kidney and the expression of profilin-1 were assessed. In cultured endothelial cells, shRNA profilin-1 was used to clarify the role of profilin-1 in AGEs-induced vascular endothelial lesions and inflammatory reactions. ResultsThe aorta, heart, and kidney of the AGE-injection rats had obvious morphological changes. Also, the indicators of vascular remodeling in the aorta significantly increased, accompanied by the increased expression of profilin-1 in the aorta, heart, and kidney and polysaccharide content on the kidney basement membrane. In addition, the protein level of profilin-1 was markedly upregulated in the aorta of AGEs-injected rats and endothelial cells incubated with AGEs. shRNA profilin-1 markedly attenuated the upregulated expression of profilin-1, receptor for AGEs (RAGE), and NF-κB in endothelial cells incubated with AGEs, as well as reduced the high levels of ICAM-1, IL-8, TNF-α, ROS, and apoptosis induced by AGEs. ConclusionsExogenous AGEs can mimic diabetic vasculopathy in vivo to some extent and increase profilin-1 expression in the target organs of diabetic complications. Blockade of profilin-1 attenuates vascular lesions and inflammatory reactions, suggesting its critical role in the metabolic memory mediated by AGEs.

Curcumin and Andrographolide Co-Administration Safely Prevent Steatosis Induction and ROS Production in HepG2 Cell Line.

Non-alcoholic fatty liver disease (NAFLD) is an emerging chronic liver disease worldwide. Curcumin and andrographolide are famous for improving hepatic functions, being able to reverse oxidative stress and release pro-inflammatory cytokines, and they are implicated in hepatic stellate cell activation and in liver fibrosis development. Thus, we tested curcumin and andrographolide separately and in combination to determine their effect on triglyceride accumulation and ROS production, identifying the differential expression of genes involved in fatty liver and oxidative stress development. In vitro steatosis was induced in HepG2 cells and the protective effect of curcumin, andrographolide, and their combination was observed evaluating cell viability, lipid and triglyceride content, ROS levels, and microarray differential gene expression. Curcumin, andrographolide, and their association were effective in reducing steatosis, triglyceride content, and ROS stress, downregulating the genes involved in lipid accumulation. Moreover, the treatments were able to protect the cytotoxic effect of steatosis, promoting the expression of survival and anti-inflammatory genes. The present study showed that the association of curcumin and andrographolide could be used as a therapeutic approach to counter high lipid content and ROS levels in steatosis liver, avoiding the possible hepatotoxic effect of curcumin. Furthermore, this study improved our understanding of the antisteatosis and hepatoprotective properties of a curcumin and andrographolide combination.

Low GSK3β activity is required for insect diapause through responding to ROS/AKT signaling and down-regulation of Smad1/EcR/HR3 cascade

Glycogen synthase kinase 3β (GSK3β) plays important roles in gene transcription, metabolism, apoptosis, development, and signal transduction. However, its role in the regulation of pupal diapause remains unclear. In this paper, we find that low GSK3β activity in brains of diapause-destined pupae of Helicoverpa armigera is caused by elevated AKT activity. In response to ROS, AKT phosphorylates GSK3β to decrease its activity. In developing pupal brains, GSK3β can activate the transcription factor Smad1, which binds to the promoter region of the ecdysone receptor (EcR) gene and increases its expression. In the presence of 20-hydroxyecdysone (20E), EcR can bind to USP and increase the expression of 20E-response genes, including HR3, for pupal-adult development. In contrast, high levels of ROS in brains of diapause-destined pupae up-regulate p-AKT, which in turn decreases GSK3β activity. Low GSK3β activity causes low expression of EcR/HR3 via down-regulation of Smad1 activity, leading to diapause initiation. These results suggest that low GSK3β activity plays a key role in pupal diapause via ROS/AKT/GSK3β/Smad/EcR/HR3 signaling.

Stimuli-responsive ferroptosis for cancer therapy.

Ferroptosis, an iron-dependent programmed cell death mechanism, is regulated by distinct molecular pathways of lipid peroxidation caused by intracellular iron supplementation and glutathione (GSH) synthesis inhibition. It has attracted a great deal of attention as a viable alternative to typical apoptosis-based cancer therapy that exhibits drug resistance. For efficient therapeutic utilization of such a unique and desirable mechanism, precise control using various stimuli to activate the administered nanocarriers is essential. Specific conditions in the tumor microenvironment (e.g., acidic pH, high level of ROS and GSH, hypoxia, etc.) can be exploited as endogenous stimuli to ensure high specificity of the tumor site. Maximized spatiotemporal controllability can be assured by utilizing external energy sources (e.g., magnetic fields, ultrasound, microwaves, light, etc.) as exogenous stimuli that can provide on-demand remote controllability for customized deep tumor therapy with a low inter-patient variation. Strikingly, the utilization of dual endogenous and/or exogenous stimuli provides a new direction for efficient cancer therapy. This review highlights recent advances in the utilization of various endogenous and exogenous stimuli to activate the reactions of nanocarriers for ferroptosis-based cancer therapy that can inspire the field of cancer therapy, particularly for the treatment of intractable tumors.

Functionalization of cellulose nanofibrils to develop novel ROS-sensitive biomaterials

Nanocellulose–oligoproline hydrogels, able to respond to high levels of ROS and protect cells from oxidative environments, are promising candidates for the treatment of chronic wounds and other clinical conditions associated with high levels of ROS.

The bridge between cell survival and cell death: reactive oxygen species-mediated cellular stress.

As a requirement of aerobic metabolism, regulation of redox homeostasis is indispensable for the continuity of living homeostasis and life. Since the stability of the redox state is necessary for the maintenance of the biological functions of the cells, the balance between the pro-oxidants, especially ROS and the antioxidant capacity is kept in balance in the cells through antioxidant defense systems. The pleiotropic transcription factor, Nrf2, is the master regulator of the antioxidant defense system. Disruption of redox homeostasis leads to oxidative and reductive stress, bringing about multiple pathophysiological conditions. Oxidative stress characterized by high ROS levels causes oxidative damage to biomolecules and cell death, while reductive stress characterized by low ROS levels disrupt physiological cell functions. The fact that ROS, which were initially attributed as harmful products of aerobic metabolism, at the same time function as signal molecules at non-toxic levels and play a role in the adaptive response called mithormesis points out that ROS have a dose-dependent effect on cell fate determination. See also Figure 1(Fig. 1).

WSL214 negatively regulates ROS accumulation and pathogen defense response in rice.

WSL214 plays an important role in promoting cellular ROS homeostasis by enhancing catalase activity and reducing photosynthetic ROS production. ROS are the important regulator of cellular homeostasis, and balancing ROS production and clearance contributes to cellular activity. Although many genes associated with ROS have been cloned, the mechanism of this balance is not fully understood. In this study, we obtained the rice mutant wsl214 that arose from a natural mutation. Compared to WT, wsl214 exhibited white-striped leaves, defective chloroplast development, reduced net photosynthetic rate, and overexcitation of photosynthetically active reaction centers. In addition, the ROS accumulation level was significantly elevated, and the ROS scavenging enzyme activity was significantly decreased in wsl214 leaf tissue. As a result of elevated ROS levels, wsl214 leaf cells underwent DNA damage and programmed cell death. However, wsl214 defense response to exogenous pathogens was also enhanced by high ROS levels. Based on the mapping cloning, we discovered that WSL214 had a single base mutation (C to T) in the third exon, resulting in decreased expression of wsl214. The WSL214 encodes an HD domain phosphohydrolase and is widely expressed in various tissues of rice, especially at the highest level in leaf tissue. Further research showed that WSL214 promoted the homeostasis of rice leaf cellular ROS in two ways. First, WSL214 increased the expression of the catalase gene OsCATC, making the intracellular ROS scavenging enzyme more active.Second, WSL214 promoted chloroplast development, kept photosynthesis working properly, and reduced ROS produced by photosynthesis.In conclusion, our report emphasizes that WSL214 is a key part of balancing ROS levels in cells.

Muscle fiber characteristics and apoptotic factor differences in beef Longissimus lumborum and Psoas major during early postmortem

This study was conducted to study muscle fiber characteristics and apoptotic factor differences within 24 h postmortem of bovine longissimus lumborum (LL) and psoas major (PM). Compared to LL, PM had a higher proportion of type I fibers and lower proportion of type II fibers. PM also had higher ROS levels. For bcl-2 family proteins, anti-apoptotic BCL-2 level was lower and pro-apoptotic BAX level was higher in PM. For caspases, at 1 h postmortem, gene and protein expression level of caspase-3 and caspase-9 was higher in PM than that of LL. The levels of DNA damage apoptotic factors ABL1, AIF and ENDOG was higher in PM than in LL. The results suggested that apoptotic gene and protein expression were different in muscles with different fiber type composition. These findings provided insights into muscle fiber and apoptotic factor differences during early postmortem in bovine PM and LL.

Mechanistic role of epigallocatechin-3-gallate in regulation of the antioxidant markers in ethanol induced liver damage in mice

ABSTRACT Background: Failure of endogenous antioxidant system to eliminate high levels of ROS results to oxidative stress, consequently leading to liver damage. Excessive alcohol consumption leads to liver damage due to ROS generation, thus regarded as the leading causes of death worldwide, suggesting great need for use of exogenous antioxidants like epigallocatechin-3-gallate (EGCG), to avert liver damage. However, underlying EGCG mechanisms remains elusive.Aim of the work: This study focused on mechanistic role of EGCG in regulation of antioxidant marker activities during ethanol induced liver damage.Materials and Methods: 20 male Swiss Albino mice were divided into four groups and treated with different dosage. ALT, AST and total proteins were determined as indicators of liver damage. MDA and protein carbonyls were measured as oxidative stress markers. Activities of SOD and CAT were determined. SOD-2 and CAT differential gene expression were also determined. Liver histology analysis by H&E staining. All the experiments were run in duplicates. ANOVA was used to analyzes data using Tukey’s multiple comparison tests and results considered statistically significant if p ≤ 0.05 at 95% confidence level. Results: Findings revealed that chronic consumption of ethanol leads to liver damage through increased levels of serum ALT and AST, MDA, protein carbonyls and remarkable diffuse lipid droplets and decreased enzyme activity of SOD and CAT. EGCG increased activity of SOD and CAT and SOD-2 expression and did not affect CAT expression. Conclusion: In summary, ethanol induces liver damage, and administration of EGCG increases antioxidant system expression, suggesting its role in regulating their activities, defensive of oxidative stress through various pathways.

Protective effect of multifunctional peptides PIISVYWK and FSVVPSPK on oxidative stress-mediated HUVEC injury through antioxidant and anti-apoptotic action

PIISVYWK and FSVVPSPK are antioxidant peptides identified from blue mussel protein. In the present study, the cytoprotective function of the two peptides on H2O2-mediated injuries in human umbilical vein endothelial cells (HUVECs) was evaluated. The results indicated that the peptides significantly restored cell survival (p < 0.05) in response to damage caused by H2O2 exposure. HUVECs treated with H2O2 generated high levels of ROS. While the elevated intracellular levels of ROS were decreased by the treatment with peptides; the result may be attributed to the elevated heme oxygenase-1 expression through Nrf2 nuclear translocation. Investigation of another underlying mechanism revealed that the peptides inhibited the apoptotic process in HUVECs that was induced by H2O2 exposure. Highly elevated levels of apoptotic Bax expression, the release of cytochrome C into the cytoplasm, and the cleaved caspase-3 expression were observed along with the loss of mitochondrial membrane potential (MMP). The peptides downregulated the expression of Bax and the cleaved caspase-3, inhibited the release of cytochrome C, and restored MMP in response to H2O2-mediated HUVECs injuries. In addition, the peptides increased the expression of antiapoptotic Bcl-2.