dj-1β regulates oxidative stress,insulin-like signaling and development in Drosophila melanogaster

DJ-1 (or PARK-7) is a multifunctional protein implicated in numerous pathologies including cancer, sterility and Parkinson disease (PD). The popular genetic model Drosophila melanogaster has two orthologs, dj-1: α and β. Dysfunction of dj-1β strongly impairs fly mobility in an age-dependent manner. In this study, we analyze in detail the molecular mechanism underlying the dj-1β mutant phenotype. Mitochondrial hydrogen peroxide production, but not superoxide production, was increased in mutant flies. An increase in peroxide leak from mitochondria causes oxidative damage elsewhere and explains the strong reduction in mobility caused by dj-1β mutation. However, at the same time, increased levels of hydrogen peroxide activated a pro-survival program characterized by (1) an alteration in insulin-like signaling, (2) an increase in mitochondrial biogenesis and (3) an increase in the de-acetylase activity of sirtuins. The activation of this pro-survival program was associated with increased longevity under conditions of moderate oxidative stress. Additionally, the dj-1β mutation unexpectedly accelerated development, a phenotype not previously associated with this mutation. Our results reveal an important role of dj-1β in oxidative stress handling, insulin-like signaling and development in Drosophila melanogaster.     

Molecular changes in hepatic metabolism in ZDSD rats–A new polygenic rodent model of obesity,metabolic syndrome,and diabetes

In recent years, the prevalence of obesity, metabolic syndrome and type 2 diabetes is increasing dramatically. They share pathophysiological mechanisms and often lead to cardiovascular diseases. The ZDSD rat was suggested as a new animal model to study diabetes and the metabolic syndrome. In the current study, we have further characterized metabolic and hepatic gene expression changes in ZDSD rats. Immuno-histochemical staining of insulin and glucagon on pancreas sections of ZDSD and control SD rats revealed that ZDSD rats have severe damage to their islet structures as early as 15 weeks of age. Animals were followed till they were 26 weeks old, where they exhibited obesity, hypertension, hyperglycemia, dyslipidemia, insulin resistance and diabetes. We found that gene expressions involved in glucose metabolism, lipid metabolism and amino acid metabolism were changed significantly in ZDSD rats. Elevated levels of ER stress markers correlated with the dysregulation of hepatic lipid metabolism in ZDSD rats. Key proteins participating in unfolded protein response pathways were also upregulated and likely contribute to the pathogenesis of dyslipidemia and insulin resistance. Based on its intact leptin system, its insulin deficiency, as well as its timeline of disease development without diet manipulation, this insulin resistant, dyslipidemic, hypertensive, and diabetic rat represents an additional, unique polygenic animal model that could be very useful to study human diabetes.     

Ginger extract mitigates ethanol-induced changes of alpha and beta – myosin heavy chain isoforms gene expression and oxidative stress in the heart of male wistar rats

The association between ethanol consumption and heart abnormalities, such as chamber dilation, myocyte damage, ventricular hypertrophy, and hypertension is well known. However, underlying molecular mediators involved in ethanol-induced heart abnormalities remain elusive. The aim of this study was to investigate the effect of chronic ethanol exposure on alpha and beta – myosin heavy chain (MHC) isoforms gene expression transition and oxidative stress in rats’ heart. It was also planned to find out whether ginger extract mitigated the abnormalities induced by ethanol in rats’ heart. Male wistar rats were divided into three groups of eight animals as follows: Control, ethanol, and ginger extract treated ethanolic (GETE) groups. After six weeks of treatment, the results revealed a significant increase in the β-MHC gene expression, 8- OHdG amount, and NADPH oxidase level. Furthermore, a significant decrease in the ratio of α-MHC/β-MHC gene expression to the amount of paraoxonase enzyme in the ethanol group compared to the control group was found. The consumption of Ginger extract along with ethanol ameliorated the changes in MHC isoforms gene expression and reduced the elevated amount of 8-OHdG and NADPH oxidase. Moreover, compared to the consumption of ethanol alone, it increased the paraoxonase level significantly.These findings indicate that ethanol-induced heart abnormalities may in part be associated with MHC isoforms changes mediated by oxidative stress, and that these effects can be alleviated by using ginger extract as an antioxidant molecule.     

A role for age-related changes in TGFβ signaling in aberrant chondrocyte differentiation and osteoarthritis

Transforming growth factor beta (TGFβ) is a growth factor with many faces. In our osteoarthritis (OA) research we have found that TGFβ can be protective as well as deleterious for articular cartilage. We postulate that the dual effects of TGFβ on chondrocytes can be explained by the fact that TGFβ can signal via different receptors and related Smad signaling routes. On chondrocytes, TGFβ not only signals via the canonical type I receptor ALK5 but also via the ALK1 receptor. Notably, signaling via ALK5 (Smad2/3 route) results in markedly different chondrocyte responses than ALK1 signaling (Smad1/5/8), and we postulate that the balance between ALK5 and ALK1 expression on chondrocytes will determine the overall effect of TGFβ on these cells. Importantly, signaling via ALK1, but not ALK5, stimulates MMP-13 expression by chondrocytes. In cartilage of ageing mice and in experimental OA models we have found that the ALK1/ALK5 ratio is significantly increased, favoring TGFβ signaling via the Smad1/5/8 route, changes in chondrocyte differentiation and MMP-13 expression. Moreover, human OA cartilage showed a significant correlation between ALK1 and MMP-13 expression. In this paper we summarize concepts in OA, its link with ageing and disturbed growth factor responses, and a potential role of TGFβ signaling in OA development.     

A pivotal role for beta-aminoisobutyric acid and oxidative stress in dihydropyrimidine dehydrogenase deficiency?

Dihydropyrimidine dehydrogenase (DPD) constitutes the first step of the pyrimidine degradation pathway in which the pyrimidine bases uracil and thymine are catabolised to beta-alanine and beta-aminoisobutyric acid (beta-AIB), respectively. The mean concentration of beta-AIB was approximately 5- to 8-fold lower in urine of patients with a DPD deficiency, when compared to age-matched controls. Comparable levels of 8-hydroxydeoxyguanosine (8-OHdG) were present in urine from controls and DPD patients at the age <2 year. In contrast, slightly elevated levels of 8-OHdG were detected in urine from DPD patients with an age >2 year, suggesting the presence of increased oxidative stress.     

Evaluation of cytokines,oxidative stress markers and brain-derived neurotrophic factor in patients with fibromyalgia – A controlled cross-sectional study

ObjectivesPrevious studies measuring serum levels of biomarkers of inflammation/oxidative stress and neurotrophins levels in fibromyalgia (FM) have rendered inconsistent results. In the present study, our aim was to explore the levels of interleukins, oxidative stress markers and brain-derived neurotrophic factor (BDNF) in patients with FM in relation to depression and severity of disease.MethodsIn a prospective controlled cross-sectional study, serum concentrations of IL-6, IL-8, IL-10, TNF-α, thiobarbituric acid reactive substances (TBARS), protein carbonyl and BDNF were measured in 69 FM patients and 61 healthy controls (all women). In the FM group, the Fibromyalgia Impact Questionnaire (FIQ), the Beck Depression Inventory (BDI) and the Hamilton Depression Rating Scale (HDRS) were applied. Mann Whitney’s and Spearman correlation tests were used for statistical analysis.ResultsThe FM patients demonstrated a significant impact of the disease on quality of life (FIQ 70.2 ± 17.8) and most of them had depression at some level (82.6% and 87.0% as assessed by BDI and HDRS, respectively). Most biomarkers (IL-6, IL-8, TNF-α, TBARS and protein carbonyl) and BDNF did not differ significantly between patients and controls, but the IL-10 levels were higher in FM patients (adjusted p = 0.041). Among FM patients, there was no correlation of HDRS, FIQ, and BDI scores with any biomarker tested here.ConclusionWe observed no significant differences in biomarkers between FM patients and controls, except for higher levels of IL-10 (an anti-inflammatory cytokine) in patients. The levels of biomarkers were not correlated with parameters of disease and depression severity.     

Cell signaling and receptors in toxicity of advanced glycation end products (AGEs): α-dicarbonyls,radicals, oxidative stress and antioxidants

Considerable attention has been paid to the toxicity of advanced glycation end products (AGEs), including relation to various illnesses. AGEs, generated nonenzymatically from carbohydrates and proteins, comprises large numbers of simple and more complicated compounds. Many reports deal with a role for receptors (RAGE) and cell signaling, including illnesses and aging. Reactive oxygen species appear to participate in signaling. RAGE include angiotensin II type 1 receptors. Many signaling pathways are involved, such as kinases, p38, p21, TGF-β, NF-κβ, TNF-α, JNK and STAT. A recent review puts focus on α-dicarbonyl metabolites, formed by carbohydrate oxidation, and imine derivatives from protein condensation, as a source via electron transfer (ET) of ROS and oxidative stress (OS). The toxic species have been related to illnesses and aging. Antioxidants alleviate the adverse effects.     

Cell signaling and receptors in toxicity of advanced glycation end products (AGEs): α-dicarbonyls, radicals, oxidative stress and antioxidants

Considerable attention has been paid to the toxicity of advanced glycation end products (AGEs), including relation to various illnesses. AGEs, generated nonenzymatically from carbohydrates and proteins, comprises large numbers of simple and more complicated compounds. Many reports deal with a role for receptors (RAGE) and cell signaling, including illnesses and aging. Reactive oxygen species appear to participate in signaling. RAGE include angiotensin II type 1 receptors. Many signaling pathways are involved, such as kinases, p38, p21, TGF-β, NF-κβ, TNF-α, JNK and STAT. A recent review puts focus on α-dicarbonyl metabolites, formed by carbohydrate oxidation, and imine derivatives from protein condensation, as a source via electron transfer (ET) of ROS and oxidative stress (OS). The toxic species have been related to illnesses and aging. Antioxidants alleviate the adverse effects.     

Estrogen signaling,through estrogen receptor β, regulates DNA methylation and its machinery in male germ line in adult rats

Estrogen, through its receptors, regulates various aspects of spermatogenesis and male fertility. To understand the roles of estrogen receptors (ERα and ERβ) in male fertility, we have developed in vivo selective ER agonist administration models. Treatment of adult male rats with ERα or ERβ agonist for 60 d decreases fertility and litter size mainly due to increased pre- and post-implantation embryo loss. Since epigenetic mechanisms like DNA methylation play a crucial role in male fertility, we investigated the effects of the ER agonists on DNA methylation in spermatozoa. Treatment with ERβ agonist causes a significant decrease in DNA methylation both at the global level and at the H19 differentially methylated region (DMR). This could be due to decrease in DNA methyltransferases in the testis upon ERβ agonist treatment. The hypomethylation observed at the H19 DMR corroborates with aberrant expression of Igf2 and H19 imprinted genes in the resorbed embryos sired by ERβ agonist-treated males. Thus, our study demonstrates that ERβ regulates DNA methylation and methylating enzymes during adult rat spermatogenesis. Activation of estrogen signaling through ERβ could therefore cause DNA methylation defects leading to impaired male fertility. These results define a role for estrogen in epigenetic regulation of male germ line, suggesting that epigenetic insults by exposure to environmental estrogens could potentially affect male fertility.     

Distribution and fate of DCX/PSA-NCAM expressing cells in the adult mammalian cortex: A local reservoir for adult cortical neuroplasticity?

The expression of early developmental markers such as doublecortin (DCX) and the polysialylated-neural cell adhesion molecule (PSA-NCAM) has been used to identify immature neurons within canonical neurogenic niches. Additionally, DCX/PSA-NCAM+ immature neurons reside in cortical layer II of the paleocortex and in the paleo- and entorhinal cortex of mice and rats, respectively. These cells are also found in the neocortex of guinea pigs, rabbits, some afrotherian mammals, cats, dogs, non-human primates, and humans. The population of cortical DCX/PSA-NCAM+ immature neurons is generated prenatally as conclusively demonstrated in mice, rats, and guinea pigs. Thus, the majority of these cells do not appear to be the product of adult proliferative events. The immature neurons in cortical layer II are most abundant in the cortices of young individuals, while very few DCX/PSA-NCAM + cortical neurons can be detected in aged mammals. Maturation of DCX/PSA-NCAM+ cells into glutamatergic and GABAergic neurons has been proposed as an explanation for the age-dependent reduction in their population over time. In this review, we compile the recent information regarding the age-related decrease in the number of cortical DCX/PSA-NCAM+ neurons. We compare the distribution and fates of DCX/PSA-NCAM + neurons among mammalian species and speculate their impact on cognitive function. To respond to the diversity of adult neurogenesis research produced over the last number of decades, we close this review by discussing the use and precision of the term “adult non-canonical neurogenesis.”     

Adlay hull extracts attenuate β-amyloid-induced neurotoxicity and oxidative stress in PC12 cells through antioxidative,anti-inflammatory,and antiapoptotic activities

Alzheimer's disease (AD) is characterized by accumulation of β-amyloid (Aβ) in senile plaques, contributing to oxidative stress, mitochondrial diseases, and synaptic atrophy, consequently leading to the deterioration of brain function. Adlay (Coix lacryma-jobi L.) is an annual botanical. Here, a 95% ethanol extract of adlay hull (AHEE) was partitioned by ethyl acetate (AHEAE), n-butanol (AHBUE), and water (AHWE), and the effects of these extracts on lipopolysaccharide (LPS)-induced RAW264.7 cells and Aβ-induced PC12 cells, as experimental models of neurotoxicity, were evaluated. The expression of anti-inflammatory and antiapoptosis-related proteins was investigated and AHEE, AHEAE, and AHWE were found to exert anti-inflammatory effects. AHWE exhibited antiapoptotic effects and inhibited inducible nitric oxide synthase expression and nitric oxide production. We investigated the protective effects of AHWE against Aβ-induced neurotoxicity in dPC12 cells and explored the underlying mechanism. Pretreatment with AHWE significantly attenuated cell death and Aβ-mediated increase in B cell lymphoma (Bcl)-2/Bax ratio. AHWE significantly inhibited Aβ and enhanced protein kinase B (Akt) level in dPC12 cells, suggesting that its protective effect against Aβ-induced apoptosis in dPC12 cells was mediated through upregulation of the phosphoinositide 3-kinases (PI3K)/Akt signaling pathway. These extracts and its bioactive compound K36–21 may be potentially useful to treat neurodegenerative disorders.     

Impact of α-lipoic acid on liver peroxisome proliferator-activated receptor-α, vascular remodeling, and oxidative stress in insulin-resistant rats

This study sought to determine the impact of α-lipoic acid (LA) on superoxide anion (O(2)(?-)) production and peroxisome proliferator-activated receptor-α (PPARα) expression in liver tissue, plasma free fatty acids (FFA), and aortic remodeling in a rat model of insulin resistance. Sprague-Dawley rats (50-75 g) were given either tap water or a drinking solution containing 10% D-glucose for 14 weeks, combined with a diet with or without LA supplement. O(2)(?-) production was measured by lucigenin chemiluminescence, and PPAR-α expression by Western blotting. Cross-sectional area (CSA) of the aortic media and lumen and number of smooth muscle cells (SMC) were determined histologically. Glucose increased systolic blood pressure (SBP), plasma levels of glucose and insulin, and insulin resistance (HOMA index). All of these effects were attenuated by LA. Whereas glucose had no effect on liver PPAR-α protein level, it decreased plasma FFA. LA decreased the aortic and liver O(2)(?-) production, body weight, and plasma FFA levels in control and glucose-treated rats. Liver PPAR-α protein levels were increased by LA, and negatively correlated with plasma FFA. Medial CSA was reduced in all glucose-treated rats, and positively correlated with plasma FFA but not with SBP or aortic O(2)(?-) production. Glucose also reduced aortic lumen area, so that the media-to-lumen ratio remained unchanged. The ability of LA to lower plasma FFA appears to be mediated, in part, by increased hepatic PPAR-α expression, which may positively affect insulin resistance. Glucose-fed rats may serve as a unique model of aortic atrophic remodeling in hypertension and early metabolic syndrome.     

Neurogenic dysregulation, oxidative stress, autoimmunity, and melanocytorrhagy in vitiligo: can they be interconnected?

Several hypotheses have been proposed to explain vitiligo, including the neural theory, impaired redux status, autoimmunity, and more recently melanocytorrhagy arising from defective cell-cell adhesion. It is most likely that the loss of melanocytes in vitiligo arises through a combination of pathogenic mechanisms that act in concert. Here, we discuss the potential interconnection of several mechanisms that are likely to operate. These include the alteration of melanocyte-specific factors by reactive oxygen species to produce neo-antigens and the role of hypoxia and oxidative stress in antigen presentation and the auto-immune destruction of melanocytes.     

Neurogenic dysregulation,oxidative stress,autoimmunity, and melanocytorrhagy in vitiligo: can they be interconnected?

Several hypotheses have been proposed to explain vitiligo, including the neural theory, impaired redux status, autoimmunity, and more recently melanocytorrhagy arising from defective cell‐cell adhesion. It is most likely that the loss of melanocytes in vitiligo arises through a combination of pathogenic mechanisms that act in concert. Here, we discuss the potential interconnection of several mechanisms that are likely to operate. These include the alteration of melanocyte‐specific factors by reactive oxygen species to produce neo‐antigens and the role of hypoxia and oxidative stress in antigen presentation and the auto‐immune destruction of melanocytes.     

Protective effects of curcumin against lithium–pilocarpine induced status epilepticus,cognitive dysfunction and oxidative stress in young rats

Status epilepticus (SE), one of the most severe forms of epilepsy is regarded a medical emergency with considerable morbidity and mortality. Due to the limited efficacy and enormous side effects of currently available drugs, a search for new safe and effective therapeutic agents is critical using experimentally induced SE in animals. The lithium–pilocarpine (Li–Pc) model of SE is most suitable and frequently used for pathophysiological and management strategies of SE. Recent studies have shown significant potential of pharmacological, prophylactic or therapeutic use of curcumin (Cur) in many beneficial activities in the body including neuroprotection in neurodegenerative diseases and antioxidant properties. The present study describes anticonvulsive effects of Cur in Li–Pc induced SE in young rats. The effect of Cur was examined on the intensity and frequency of SE, cognitive behavior in water maze as well as on oxidative stress related enzymes in the brain. Besides its anticonvulsant effect, Cur significantly ameliorates SE-induced cognitive dysfunction and oxidative damages in the hippocampus and striatum areas of the brain. Possible therapeutic application of Cur as an anticonvulsant and as an antioxidant for the treatment of SE has a great potential and warrants further studies.     

5-Phenylselenyl- and 5-methylselenyl-methyl-2′-deoxyuridine induce oxidative stress, DNA damage, and caspase-2-dependent apoptosis in cancer cells

In the present study, we investigated the signaling pathways implicated in the induction of apoptosis by two modified nucleosides, 5-phenylselenyl-methyl-2′-deoxyuridine (PhSe-T) and 5-methylselenyl-methyl-2′-deoxyuridine (MeSe-T), using human cancer cell lines. The induction of apoptosis was associated with proteolytic activation of caspase-3 and -9, PARP cleavage, and decreased levels of IAP family members, including c-IAP-1 and c-IAP-2, but had no effect on XIAP and survivin. PhSe-T and MeSe-T also enhanced the activities of caspase-2 and -8, Bid cleavage, and the conformational activation of Bax. Additionally, nucleoside derivative-induced apoptosis was inhibited by the selective inhibitors of caspase-2, -3, -8, and -9 and also by si-RNAs against caspase-2, -3, -8, and -9; however, inhibition of caspase-2 and -3 was more effective at preventing apoptosis than inhibition of caspase-8 and -9. Moreover, the inhibition of caspase-2 activation by the pharmacological inhibitor z-VDVAD-fmk or by the knockdown of protein expression using siRNA suppressed nucleoside derivative-induced caspase-3 activation, but not vice versa. PhSe-T and MeSe-T also induced a Δψ_m loss via a CsA-insensitive mechanism, ROS production, and DNA damage, including strand breaks. Moreover, ROS scavengers such as NAC, tiron, and quercetin inhibited nucleoside derivative-induced ROS generation and apoptosis by blocking the sequential activation of caspase-2 and -3, indicating the role of ROS in caspase-2-mediated apoptosis. Taken together, these results indicate that caspase-2 acts upstream of caspase-3 and that caspase-2 functions in response to DNA damage in both PhSe-T- and MeSe-T-induced apoptosis. Our results also suggest that ROS are critical regulators of the sequential activation of caspase-2 and -3 in nucleoside derivative-treated cancer cells.