Reactive Oxygen Species In Pathogenesis Research Articles

Serum Paroxonase 1 level may be an Indicator and Predictor of the Severity of Androgenetic Alopecia

Background:Androgenetic alopecia (AGA) is a common stressful form of hair loss caused by androgen excess, genetic factors, and exposure to oxidative stress (OS) with the formation of reactive oxygen species (ROS). Paraoxonase 1 (PON1) is an enzyme synthesized in the liver bound to high-density lipoproteins to prevent lipid peroxidation.Aim:The aim of our work is to estimate serum PON1 level in patients with AGA and correlate its levels with disease severity which may help in determining if there is a role of ROS in pathogenesis of AGA.Subjects and Methods:This study was carried out as a case and control on 40 patients with AGA (diagnosed by typical clinical and dermoscopic finding) versus 40 control subjects. Blood samples were taken from all subjects to assess serum PON1enzyme using enzyme-linked immunosorbent assay kits.Results:There was a significant decrease in serum PON1 concentration level in AGA patients in comparison to controls, in addition, there was a significant decrease correlated with AGA severity (P < 0,001). The study proved that PON1 is considered highly sensitive and specific for AGA cases and a good predictive factor of AGA in healthy subjects.Conclusion:This is the first study done to reveal that the level of PON1 significantly decreased in AGA patients, which may give additional proof that OS has role in the pathogenesis of AGA and hence may help in the management of AGA by adding antioxidants in treatment.

P53 sensitizes chemoresistant non-small cell lung cancer via elevation of reactive oxygen species and suppression of EGFR/PI3K/AKT signaling

BackgroundNon-small cell lung cancer (NSCLC) is the leading cause of cancer deaths primarily due to chemoresistance. Somatic mutation of TP53 (36%) and epidermal growth factor receptor (EGFR; > 30%) are major contributors to cisplatin (CDDP) resistance. Substantial evidence suggests the elevated levels of reactive oxygen species (ROS) is a key determinant in cancer. The elevated ROS can affect the cellular responses to chemotherapeutic treatments. Although the role of EGFR in PI3K/Akt signaling cascade in NSCLC is extensively studied, the molecular link between EGFR and p53 and the role of ROS in pathogenesis of NSCLC are limitedly addressed. In this study, we investigated the role of p53 in regulation of ROS production and EGFR signaling, and the chemosensitivity of NSCLC.MethodsIn multiple NSCLC cell lines with varied p53 and EGFR status, we compared and examined the protein contents involved in EGFR-Akt-P53 signaling loop (EGFR, P-EGFR, Akt, P-Akt, p53, P-p53) by Western blot. Apoptosis was determined based on nuclear morphological assessment using Hoechst 33258 staining. Cellular ROS levels were measured by dichlorofluorescin diacetate (DCFDA) staining followed by flow cytometry analysis.ResultsWe have demonstrated for the first time that activation of p53 sensitizes chemoresistant NSCLC cells to CDDP by down-regulating EGFR signaling pathway and promoting intracellular ROS production. Likewise, blocking EGFR/PI3K/AKT signaling with PI3K inhibitor elicited a similar response. Our findings suggest that CDDP-induced apoptosis in chemosensitive NSCLC cells involves p53 activation, leading to suppressed EGFR signaling and ROS production. In contrast, in chemoresistant NSCLC, activated Akt promotes EGFR signaling by the positive feedback loop and suppresses CDDP-induced ROS production and apoptosis.ConclusionCollectively, our study reveals that the interaction of the p53 and Akt feedback loops determine the fate of NSCLC cells and their CDDP sensitivity.

Effects of Camphorquinone on Cytotoxicity, Cell Cycle Regulation and Prostaglandin E2 Production of Dental Pulp Cells: Role of ROS, ATM/Chk2, MEK/ERK and Hemeoxygenase-1.

Camphorquinone (CQ) is a popularly-used photosensitizer in composite resin restoration. In this study, the effects of CQ on cytotoxicity and inflammation-related genes and proteins expression of pulp cells were investigated. The role of reactive oxygen species (ROS), ATM/Chk2/p53 and hemeoxygenase-1 (HO-1) and MEK/ERK signaling was also evaluated. We found that ROS and free radicals may play important role in CQ toxicity. CQ (1 and 2 mM) decreased the viability of pulp cells to about 70% and 50% of control, respectively. CQ also induced G2/M cell cycle arrest and apoptosis of pulp cells. The expression of type I collagen, cdc2, cyclin B, and cdc25C was inhibited, while p21, HO-1 and cyclooxygenase-2 (COX-2) were stimulated by CQ. CQ also activated ATM, Chk2, and p53 phosphorylation and GADD45α expression. Besides, exposure to CQ increased cellular ROS level and 8-isoprostane production. CQ also stimulated COX-2 expression and PGE2 production of pulp cells. The reduction of cell viability caused by CQ can be attenuated by N-acetyl-L-cysteine (NAC), catalase and superoxide dismutase (SOD), but can be promoted by Zinc protoporphyin (ZnPP). CQ stimulated ERK1/2 phosphorylation, and U0126 prevented the CQ-induced COX-2 expression and prostaglandin E2 (PGE2) production. These results indicate that CQ may cause cytotoxicity, cell cycle arrest, apoptosis, and PGE2 production of pulp cells. These events could be due to stimulation of ROS and 8-isoprostane production, ATM/Chk2/p53 signaling, HO-1, COX-2 and p21 expression, as well as the inhibition of cdc2, cdc25C and cyclin B1. These results are important for understanding the role of ROS in pathogenesis of pulp necrosis and pulpal inflammation after clinical composite resin filling.

Redox biomarkers in cardiovascular medicine.

The central role of oxidative signalling in cardiovascular pathophysiology positions biometric measures of redox state as excellent markers for research and clinical application. However, despite this tantalizing biological plausibility, no redox biomarker is currently in widespread clinical use. Major recent insights into the mechanistic complexities of redox signalling may yet provide the opportunity to identify markers that most closely reflect the underlying pathobiology. Such redox biomarkers may, in principle, quantify the integrated effects of various known and unknown pathophysiological drivers of cardiovascular disease processes. Recent advances with the greatest potential include assays measuring post-translational oxidative modifications that have significant cellular effects. However, analytical issues, including the relative instability of redox-modified products, remain a major technical obstacle. Appreciation of these challenges may facilitate future development of user-friendly markers with prognostic value in addition to traditional risk factors, and which could be used to guide personalized cardiovascular therapies. We review both established and recently identified biomarkers of redox signalling, and provide a realistic discussion of the many challenges that remain if they are to be incorporated into clinical practice. Despite the current lack of redox biomarkers in clinical application, the integral role of reactive oxygen species in pathogenesis of cardiovascular disease provides a strong incentive for continued efforts.

Development Of t-MDS In Patients Undergoing Autologous Transplantation For Lymphoma Is Not Associated With Increased Frequency Of Mitochondrial DNA Mutations

Therapy-related myelodysplasia/acute myeloid leukemia (t-MDS) is a lethal complication of cytotoxic cancer treatment. The incidence of t-MDS is particularly high in patients undergoing autologous hematopoietic cell transplantation (aHCT) for Hodgkin lymphoma (HL) or non-Hodgkin lymphoma (NHL). To better understand pathogenetic mechanisms underlying development of t-MDS we are prospectively following a cohort of patients undergoing aHCT for lymphoma at our center. In previous studies using samples from this cohort we identified altered expression of genes related to mitochondrial function in pre-aHCT samples from lymphoma patients who later developed t-MDS (cases) compared to patients from the cohort who did not develop t-MDS (controls) (Cancer Cell 2011 20:591). Altered mitochondrial gene expression was associated with increased levels of mitochondrial reactive oxygen species (ROS) in samples from patients who subsequently developed t-MDS. These results suggest a possible role for mitochondrial dysfunction and increased ROS in pathogenesis of t-MDS. Somatic mutations of mitochondria DNA (mtDNA) are observed at increased frequency in many malignant conditions. Somatic mtDNA mutations may reflect increased susceptibility to mutagenesis, and could contribute to altered mitochondrial function in patients with t-MDS.Here we sought to investigate the role of mitochondrial genomic instability in t-MDS development by analyzing the mutation profile of mtDNA in hematopoietic cells from pre-HCT samples obtained from cases that developed t-MDS and controls that did not develop t-MDS after aHCT for lymphoma. We isolated myeloid and lymphoid cell populations from t-MDS cases (n=13) and controls (n=18) using flow cytometry, amplified mtDNA by PCR using specific primers, and sequenced pooled, barcoded amplicons using next generation sequencing on a Illumina Hi-Seq instrument. Sequences were alighted to the revised Cambridge Reference Sequence (rCRS) in the MITOMAP database.We did not identify significant differences in abundance of variations between controls and cases in protein coding genes (control 13.9, case 14.9), hypervariable region (control 7.7, case 6.6) and rRNA/tRNA genes (control 5.7, case 5.6). In addition we did not observe differences in the abundance of variation between cases and controls in individual genes. We also did not detect significant differences in the abundance of SNPs resulting in non-synonymous amino acid changes in lymphoid compared to myeloid populations from both cases (lymphoid 5.0, myeloid 4.7) and controls (lymphoid 5.3, myeloid 4.3). Several new variations in both coding and noncoding regions were identified that were not previously reported in the rCRS database, which were present in greater abundance in myeloid (control 5.3, case 5.3) compared to lymphoid cells (control 1.7, case 2.2). Amongst new variations, the top 5 protein coding genes with the highest number of mutations were found in myeloid cells and included NADH dehydrogenase subunit 2, 4, and 5, and cytochrome c oxidase subunit 1 and 2. We also analyzed the specific mutations that displayed a variation frequency greater than 25% in myeloid control and case samples. Interestingly, the A10398G mutation, in the NADH dehydrogenase subunit 3 (ND3) coding region, associated with metabolic syndrome and increased risk for breast cancer, was found in ∼30% of t-MDS myeloid case samples.In summary our data suggests that there is increased abundance of novel variations in mtDNA in myeloid compared to lymphoid populations. Although several new, previously unreported variations were identified, we did not observe any significant differences in type of lesions, abundance of lesions in coding and non-coding regions, or in individual genes between cases and controls. We conclude that changes in mtDNA sequence are not significantly different between patients that later develop t-MDS after aHCT (cases) compared to controls that do not develop t-MDS. These observations suggest that differences in mtDNA sequence cannot by itself explain the alterations in altered mitochondrial function seen early during the course of development of t-MDS. Disclosures:No relevant conflicts of interest to declare.

Role of Reactive Oxygen Species in Pathogenesis of Radiocontrast-Induced Nephropathy

In vitro and in vivo studies have demonstrated enhanced hypoxia and formation of reactive oxygen species (ROS) in the kidney following the administration of iodinated contrast media, which play a relevant role in the development of contrast media-induced nephropathy. Many studies indeed support this possibility, suggesting a protective effect of ROS scavenging or reduced ROS formation with the administration of N-acetylcysteine and bicarbonate infusion, respectively. Furthermore, most risk factors, predisposing to contrast-induced nephropathy, are prone to enhanced renal parenchymal hypoxia and ROS formation. In this review, the association of renal hypoxia and ROS-mediated injury is outlined. Generated during contrast-induced renal parenchymal hypoxia, ROS may exert direct tubular and vascular endothelial injury and might further intensify renal parenchymal hypoxia by virtue of endothelial dysfunction and dysregulation of tubular transport. Preventive strategies conceivably should include inhibition of ROS generation or ROS scavenging.

The immunopathogenic role of reactive oxygen species in Alzheimer disease.

Reactive oxygen species (ROS) are produced in many normal and abnormal processes in humans, including atheroma, asthma, joint diseases, cancer, and aging. Basal levels of ROS production in cells could be related to several physiological functions including cell proliferation, apoptosis and homeostasis. However, excessive ROS production above basal levels would impair and oxidize DNA, lipids, sugars and proteins and consequently result in dysfunction of these molecules within cells and finally cell death. A leading theory of the cause of aging indicates that free radical damage and oxidative stress play a major role in the pathogenesis of Alzheimer disease (AD). Because the brain utilizes 20% more oxygen than other tissues that also undergo mitochondrial respiration, the potential for ROS exposure increases. In fact, AD has been demonstrated to be highly associated with cellular oxidative stress, including augmentation of protein oxidation, protein nitration, glycoloxidation and lipid peroxidation as well as accumulation of Amyloid β (Aβ). The treatment with anti-oxidant compounds can provide protection against oxidative stress and Aβ toxicity. In this review, our aim was to clarify the role of ROS in pathogenesis of AD and will discuss therapeutic efficacy of some antioxidants studies in recent years in this disease.

Control of Aspergillus niger infection in varieties of Arachis hypogeae L. by supplementation of zinc ions during seed germination

Three varieties of Arachis hypogeae, GG 11, GG 20 and GG 24, were compared for resistance against A. niger. GG 20 showed the least disease severity. Infection with A. niger resulted in a rapid increase in NADPH oxidase, Glutathione reductase (GR) and salicylic acid in all the three varieties, indicating hyper increase of reactive oxygen species (ROS) and activation of phenyl propanoid pathway. Ferric reducing antioxidant power value was found to be decreasing due to infection in all the three varieties, confirming the role of ROS in pathogenesis. Since A. niger was found to cause pathogenesis by oxidative stress, the treatment of zinc was given as an antioxidant and its effect was studied. The application of zinc inhibited NADPH oxidase and GR activity in the control as well as in the infected GG 11 and GG 24 varieties but induced in the tolerant variety GG 20. Because zinc treatment could control the ROS in GG 11 and GG 24 varieties, disease severity was reduced but in GG 20 variety, zinc treatment aggravated ROS levels and also the disease severity. The protein profile of GG 20 in comparison to GG 11 and GG 24 varieties revealed one oligomeric protein of 110 kD as one of the responsible factors for its resistance. Total oil and its iodine value were found little higher in GG 20 variety than in other two varieties. It was found that the control of ROS could control the A. niger infection in Arachis hypogeae.

Glucose oxidase induces insulin resistance via influencing multiple targets in vitro and in vivo: The central role of oxidative stress

It is well known that reactive oxygen species (ROS) plays a role in the pathogenesis of insulin resistance which is the hallmark of type 2 diabetes. However, it is still needed to clarify the mechanism underlying insulin resistance. Glucose oxidase (GOD) is an oxi-reductase catalyzing the conversion of glucose to glucolactone, which is further converted to glucuronic acid and H(2)O(2). The present study was designed to establish a rat model of insulin resistance using GOD and to investigate possible mechanisms. The results showed that three days administration of GOD could significantly increase fasting blood glucose, resulting in impaired glucose and insulin tolerance. Moreover, GOD disrupted insulin signaling both in rats and in hepatocytes, as evidenced by decreased phosphorylation of insulin-stimulated Akt, GSK3 and FOXO1α. Furthermore, GOD administration decreased the expression of PPARγ, alterated the phosphorylation of MAPKs, including p38, ERK and JNK, increased the expression of GRP78 and reduced the expression of PGC-1α and decreased the activities of ATPase and respiratory complexes, all of which have been reported to contribute to insulin resistance. Redox balance was evaluated by detecting the expression of antioxidant defenses and ROS generation. After the treatment with GOD, nuclear factorerythroid 2 p45-related factor 2 (Nrf2)-regulated antioxidant enzymes were damaged and ROS production increased significantly. N-acetyl-L-cysteine (NAC), a potent antioxidant, could notably inhibit these effects of GOD. Although further studies are needed to investigate the clear mechanism, these data also support the conclusion that, if not the most early event, ROS generation is the most important event that plays a central role in the pathogenesis of insulin resistance. Overall, our study established an insulin resistant animal model induced by GOD, elucidated the importance of ROS in pathogenesis of insulin resistance and provided the clue for further studies on the underlying mechanisms.

Genetically encoded redox sensor identifies the role of ROS in degenerative and mitochondrial disease pathogenesis

Mitochondrial dysfunction plays an important role in the pathogenesis of neurodegenerative diseases, numerous other disease states and senescence. The ability to monitor reactive oxygen species (ROS) within tissues and over time in animal model systems is of significant research value. Recently, redox-sensitive fluorescent proteins have been developed. Transgenic flies expressing genetically encoded redox-sensitive GFPs (roGFPs) targeted to the mitochondria function as a useful in vivo assay of mitochondrial dysfunction and ROS. We have generated transgenic flies expressing a mitochondrial-targeted roGFP2, demonstrated its responsiveness to redox changes in cultured cells and in vivo and utilized this protein to discover elevated ROS as a contributor to pathogenesis in a characterized neurodegeneration mutant and in a model of mitochondrial encephalomyopathy. These studies identify the role of ROS in pathogenesis associated with mitochondrial disease and demonstrate the utility of genetically encoded redox sensors in Drosophila.

Redox Control of the Survival of Healthy and Diseased Cells

Abstract Cellular redox homeostasis is the first line of defense against diverse stimuli and is crucial for various biological processes. Reactive oxygen species (ROS), byproducts of numerous cellular events, may serve in turn as signaling molecules to regulate cellular processes such as proliferation, differentiation, and apoptosis. However, when overproduced ROS fail to be scavenged by the antioxidant system, they may damage cellular components, giving rise to senescent, degenerative, or fatal lesions in cells. Accordingly, this review not only covers general mechanisms of ROS production under different conditions, but also focuses on various types of ROS-involved diseases, including atherosclerosis, ischemia/reperfusion injury, diabetes mellitus, neurodegenerative diseases, and cancer. In addition, potentially therapeutic agents and approaches are reviewed in a relatively comprehensive manner. However, due to the complexity of ROS and their cellular impacts, we believe that the goal to design more effective approaches or agents may require a better understanding of mechanisms of ROS production, particularly their multifaceted impacts in disease at biochemical, molecular, genetic, and epigenetic levels. Thus, it requires additional tools of omics in systems biology to achieve such a goal. Antioxid. Redox Signal. 15, 2867-2908.

Role of free radicals and antioxidant status in childhood nephrotic syndrome

Nephrotic syndrome (NS) is characterized by heavy proteinuria and hypoalbuminuria. Reactive oxygen species (ROS) seem to play an important role in the etiopathogenesis of proteinuria in NS. This study aims to evaluate the potential role of reactive oxygen species in pathogenesis of NS by estimating the levels of oxidants and antioxidants in children with NS. Thirty patients of NS and thirty age, sex-matched healthy subjects, were selected for the study. As compared to healthy controls, the levels of serum lipid peroxide were significantly elevated while levels of nitric oxide, erythrocyte-superoxide dismutase activity, levels of vitamin C, albumin and total antioxidant capacity were significantly reduced in nephrotic patients. The levels of uric acid and bilirubin were significantly increased in children with NS as compared to controls. There was no significant difference in vitamin E level between patients and controls. It can be concluded that increased ROS generation and decreased antioxidant defense may be related to the pathogenesis of proteinuria in NS.

Role of reactive oxygen species in pathogenesis of nephrotic syndrome

Nephrotic syndrome is the common chronic disorder characterized by alteration of permeability of the glomerular capillary wall, resulting in its inability to restrict the urinary loss of proteins. Nephrotic syndrome is characterized by heavy proteinuria, hypoalbuminemia, hyperlipidemia associated with peripheral edema. The molecular basis of glomerular permselectivity remains largely unknown. In recent years it has been proposed that Nephrotic syndrome is a consequence of an imbalance between oxidant and antioxidant activity. The present study was aimed to test that the reactive oxygen species are the mediators of excessive protein permeability and other complications of Nephrotic syndrome. For this 30 adults with Nephrotic syndrome were studied. The control group comprised 30 healthy adults matched for age. Serum levels of lipid peroxides, nitric oxide (NO⊙), α- tocopherol, ascorbic acid, erythrocyte superoxide dismutase activity, serum albumin, uric acid, cholesterol and plasma total antioxidant capacity were measured. Student's 't' test was applied for statistical analysis. There was a significant increase in lipid peroxide (1.58 ± 0.42 in controls, 3.64 ±1.3 in patients) (P<0.001) levels in study group as compared with controls. α-tocopherol (12.95 ± 1.04 in controls, 9.93 ± 1.43 in patients) (P<0.001), erythrocyte SOD activity(1.88 ± 0.9 in controls 1.07 ± 0.5 in patients) (P=0.01), serum albumin(4.06 ± 0.50 in controls, 3.04 ± 0.11 in patients) (P<0.001), and plasma total antioxidant capacity (847.33 ± 126.83 in controls, 684.00±102.94 in patients) (P<0.001) were significantly decreased. There was non-significant increase in uric acid (P>0.05), a non-significant decrease in NO⊙ (38.48 ± 15.47 in controls 37.47 ± 14.27 in patients) (P>0.05) and ascorbic acid levels ascorbic acid,( 0.95 ± 0.31in controls 0.79 ± 0.30 in patients) (P>0.05) in study group as compared with controls. Imbalance between oxidants and antioxidants may contribute to pathogenesis of proteinuria and related complications in nephrotic syndrome.

Induction of IL-8 in periodontal ligament cells by H2O2

Periodontitis is an inflammatory disease caused by bacteria. In periodontitis, reactive oxygen species (ROS) are released from inflammatory cells in response to bacteria. Interleukin (IL)-8 is one of pro-inflammatory cytokines. To investigate the role of ROS in pathogenesis of periodontitis, we estimated the effect of H(2)O(2), one of ROS, on the expression of IL-8 in human periodontal ligament (PDL) cells. PDL cells were treated with H(2)O(2). IL-8 expression was determined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). The phosphorylation of extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38) and c-jun NH(2)-terminal kinase (JNK) was estimated by Western blotting. Treatment with H(2)O(2) at concentration of up to 250 microM increased IL-8 mRNA expression and production in a concentration-dependent manner. However, treatment with 500 microM H(2)O(2) did not increase IL-8 production. Catalase, an inhibitor of H(2)O(2), down-regulated the production of IL-8 induced by H(2)O(2). H(2)O(2) increased the phosphorylation of ERK, p38, and JNK. Pretreatment with PD98059 (ERK inhibitor), SB203580 (p38 inhibitor), or SP600125 (JNK inhibitor) decreased the IL-8 production induced by H(2)O(2). These results indicate that H(2)O(2) acts as an inducer of IL-8 secretion via activation of ERK, p38, and JNK in PDL cells. H(2)O(2) deposited in periodontal tissue during inflammation against bacteria may accelerate tissue destruction via induction of IL-8 in PDL cells.

Reactive oxygen species-mediated tissue injury in experimental ascending pyelonephritis

Pyelonephritis is the most common urinary tract infection in females, but the pathogenetic mechanisms are not well understood. Reactive oxygen species (ROS) have been implicated as cause of injury in several renal diseases. In this study, we have demonstrated the role of ROS in pathogenesis of pyelonephritis in Balb/c mice. A clear correlation between extent of ROS generation and subsequent lipid peroxidation and DNA damage in kidneys was observed during the course of infection, from 2 to 14 days. Activities of brush border membrane marker enzymes were also significantly altered. Administration of antioxidants, superoxide dismutase, catalase and dimethylsulfoxide significantly reversed the histopathological changes, reduced the extent of lipid peroxidation in renal brush border membrane, and also reversed the altered enzyme activities to near normal situation. These results clearly suggest that interaction of ROS with various cellular organelles in kidneys has a significant deleterious effect, and this could be the underlying mechanism for renal dysfunction in pyelonephritis.