SOD1 and DJ-1 converge at Nrf2 pathway: a clue for antioxidant therapeutic potential in neurodegeneration

Role of Oxidative Stress and Inflammation in Doxorubicin-Induced Cardiotoxicity: A Brief Account

Cardiotoxicity is the main side effect of several chemotherapeutic drugs. Doxorubicin (Doxo) is one of the most used anthracyclines in the treatment of many tumors, but the development of acute and chronic cardiotoxicity limits its clinical usefulness. Different studies focused only on the effects of long-term Doxo administration, but recent data show that cardiomyocyte damage is an early event induced by Doxo after a single administration that can be followed by progressive functional decline, leading to overt heart failure. The knowledge of molecular mechanisms involved in the early stage of Doxo-induced cardiotoxicity is of paramount importance to treating and/or preventing it. This review aims to illustrate several mechanisms thought to underlie Doxo-induced cardiotoxicity, such as oxidative and nitrosative stress, inflammation, and mitochondrial dysfunction. Moreover, here we report data from both in vitro and in vivo studies indicating new therapeutic strategies to prevent Doxo-induced cardiotoxicity.

Update on Antioxidant Therapy with Edaravone: Expanding Applications in Neurodegenerative Diseases

The brain is susceptible to oxidative stress, which is associated with various neurological diseases. Edaravone (MCI-186, 3-methyl-1 pheny-2-pyrazolin-5-one), a free radical scavenger, has promising effects by quenching hydroxyl radicals (∙OH) and inhibiting both ∙OH-dependent and ∙OH-independent lipid peroxidation. Edaravone was initially developed in Japan as a neuroprotective agent for acute cerebral infarction and was later applied clinically to treat amyotrophic lateral sclerosis (ALS), a neurodegenerative disease. There is accumulating evidence for the therapeutic effects of edaravone in a wide range of diseases related to oxidative stress, including ischemic stroke, ALS, Alzheimer's disease, and placental ischemia. These neuroprotective effects have expanded the potential applications of edaravone. Data from experimental animal models support its safety for long-term use, implying broader applications in various neurodegenerative diseases. In this review, we explain the unique characteristics of edaravone, summarize recent findings for specific diseases, and discuss its prospects for future therapeutic applications.

A redox-based characterization of human immune cell subsets by polychromatic flow cytometry

Cellular redox state determinants are traditionally studied using fluorescent microscopy and immunoblot analysis; however, no procedure has been developed for simultaneous measurement in various immune cell subsets. Here, we present a flow cytometry assay for measuring antioxidant defense systems and reactive oxygen species simultaneously in T, B, and natural killer lymphocytes. We describe steps for preparing and treating peripheral blood mononuclear cells, surface and dye staining, cell fixation/permeabilization, and intracellular staining. We then detail machine standardization, acquisition, and analysis.

Dietary grape seed proanthocyanidin extract supplementation improves antioxidant capacity and lipid metabolism in finishing pigs

Grape seed proanthocyanidin extract (GSPE) plays a significant role in body health, including improving antioxidant capacity and maintaining lipid metabolism stability. However, whether dietary GSPE supplementation can improve lipid metabolism in finishing pigs remains unclear. Here 18 castrated male Duroc × Landrace × Yorkshire finishing pigs were randomly divided into three groups with six replicates and one pig per replicate. Pigs were fed a basal diet (control), a basal diet supplemented with 100 mg/kg GSPE, or a basal diet supplemented with 200 mg/kg GSPE for 30 days. Antioxidant analysis showed that dietary 200 mg/kg GSPE supplementation increased glutathione, total antioxidant capacity and glutathione peroxidase levels, and reduced malondialdehyde levels in serum, muscle and liver. Dietary 200 mg/kg GSPE supplementation also upregulated the mRNA and protein levels of nuclear-related factor 2 (Nrf2). Lipid metabolism analysis showed that dietary GSPE supplementation increased serum high-density lipoprotein cholesterol levels and reduced serum triglyceride and total cholesterol levels. Besides, GPSE upregulated the mRNA expression of lipolysis- and fatty acid oxidation-related genes downregulated the mRNA expression of lipogenesis-related genes, and activated the AMPK signal in finishing pigs. Together, we provided evidence that dietary GSPE supplementation improved the antioxidant capacity and lipid metabolism in finishing pigs.

Water Extract of Capsella bursa-pastoris Mitigates Doxorubicin-Induced Cardiotoxicity by Upregulating Antioxidant Enzymes

Doxorubicin (DOX), an effective chemotherapeutic drug, causes cardiotoxicity in a cumulative and dose-dependent manner. The aim of this study is to investigate the effects of hot-water extract of Capsella bursa-pastoris (CBW) on DOX-induced cardiotoxicity (DICT). We utilized H9c2 rat cardiomyocytes and MDA-MB-231 human breast cancer cells to evaluate the effects of CBW on DOX-induced cell death. Superoxide dismutase (SOD) levels, reactive oxygen species (ROS) production, and oxygen consumption rate were measured in H9c2 cells. C57BL/6 mice were treated with DOX and CBW to assess their impact on various cardiac parameters. Human-induced pluripotent stem-cell-derived cardiomyocytes were also used to investigate DOX-induced electrophysiological changes and the potential ameliorative effects of CBW. UPLC-TQ/MS analysis identified seven flavonoids in CBW, with luteolin-7-O-glucoside and isoorientin as the major compounds. CBW inhibited DOX-induced death of H9c2 rat cardiomyocytes but did not affect DOX-induced death of MDA-MB-231 human breast cancer cells. CBW increased SOD levels in a dose-dependent manner, reducing ROS production and increasing the oxygen consumption rate in H9c2 cells. The heart rate, RR interval, QT, and ST prolongation remarkably recovered in C57BL/6 mice treated with the combination of DOX and CBW compared to those in mice treated with DOX alone. Administration of CBW with DOX effectively alleviated collagen accumulation, cell death in mouse heart tissues, and reduced the levels of creatinine kinase (CK) and lactate dehydrogenase (LDH) in serum. Furthermore, DOX-induced pathological electrophysiological features in human-induced pluripotent stem-cell-derived cardiomyocytes were ameliorated by CBW. CBW may prevent DICT by stabilizing SOD and scavenging ROS. The presence of flavonoids, particularly luteolin-7-O-glucoside and isoorientin, in CBW may contribute to its protective effects. These results suggest the potential of CBW as a traditional therapeutic option to mitigate DOX-induced cardiotoxicity.

Aripiprazole attenuates the medial prefrontal cortex morphological and biochemical alterations in rats with neonatal ventral hippocampus lesion

Schizophrenia is a neurodevelopmental disorder characterized by a loss of dendritic spines in the medial prefrontal cortex (mPFC). Multiple subclinical and clinical studies have evidenced the ability of antipsychotics to improve neuroplasticity. In this study, it was evaluated the effect of the atypical antipsychotic aripiprazole (ARI) on the behavioral and mPFC neuronal disturbances of rats with neonatal ventral hippocampus lesion (nVHL), which is a heuristic developmental model relevant to the study of schizophrenia. ARI attenuated open field hyperlocomotion in the rats with nVHL. Also, ARI ameliorated structural neuroplasticity disturbances of the mPFC layer 3 pyramidal cells, but not in the layer 5 neurons. These effects can be associated with the ARI capability of increasing brain-derived neurotrophic factor (BDNF) levels. Moreover, in the animals with nVHL, ARI attenuated the immunoreactivity for some oxidative stress-related molecules such as the nitric oxide synthase 2 (NOS-2), 3-nitrotyrosine (3-NT), and cyclooxygenase 2 (COX-2), as well as the reactive astrogliosis in the mPFC. These results contribute to current knowledge about the neurotrophic, anti-inflammatory, and antioxidant properties of antipsychotics which may be contributing to their clinical effects and envision promising therapeutic targets for the treatment of schizophrenia.

The Role of Asiatic Acid in Preventing Dental Pulp Inflammation: An in-vivo Study

Purpose

Acute dental pulp inflammation necessitates early treatment to alleviate inflammation and pain. In the inflammatory phase, a substance is required to lower the inflammatory mediators and reactive oxygen species that play a crucial role in that phase. Asiatic acid is a natural triterpene obtained from the Centella asiatica plant with a high antioxidant value. This study examined the effect of Asiatic acid's antioxidant, anti-inflammatory, and antinociceptive properties on dental pulp inflammation.

Methods

The research is an experimental laboratory, with a post-test only with a control group design. The study utilised 40 male Wistar rats weighing 200-250 grams and aged 8-10 weeks. Rats were divided into five groups (control, eugenol, Asiatic Acid 0.5%; 1%; 2% group). Dental pulp inflammation was created in the maxillary incisor after six hours of administration of lipopolysaccharides (LPS). The dental pulp treatment then continued with the administration of eugenol and three different Asiatic acid concentrations (0.5%, 1% and 2%). In the next 72 hours, the teeth were biopsied, and the dental pulp was analysed using the enzyme-linked immunosorbent assay (ELISA) to measure the level of MDA, SOD, TNF-α, beta-endorphins and CGRP. Histopathological examination and the Rat Grimace Scale were utilised to determine the level of inflammation and pain, respectively.

Results

The effect of Asiatic Acid on MDA, TNF-α, and CGRP levels decreased significantly compared to the control group (p=<0.001). On the SOD and beta-endorphin levels, Asiatic acid treatment resulted in a considerable rise (p =<0.001).

Conclusion

Due to its antioxidant, anti-inflammatory, and antinociceptive characteristics, Asiatic acid can reduce inflammation and pain in acute pulp inflammation due to its ability to decrease MDA, TNFα, and CGRP levels while raising SOD and beta-endorphin levels.

PARP2 poly(ADP-ribosyl)ates nuclear factor erythroid 2-related factor 2 (NRF2) affecting NRF2 subcellular localization

PARP2 is a member of the PARP enzyme family. Although, PARP2 plays role in DNA repair, it has regulatory roles in mitochondrial and lipid metabolism, it has pivotal role in bringing about the adverse effects of pharmacological PARP inhibitors. Previously, we showed that the ablation of PARP2 induces oxidative stress and, consequently, mitochondrial fragmentation. In attempt to identify the source of the reactive species we assessed the possible role of a central regulator of cellular antioxidant defense, nuclear factor erythroid 2-related factor 2 (NRF2). The silencing of PARP2 did not alter either the mRNA or the protein expression of NRF2, but changed its subcellular localization, decreasing the proportion of nuclear, active fraction of NRF2. Pharmacological inhibition of PARP2 partially restored the normal localization pattern of NRF2 and in line with that, we showed that NRF2 is PARylated that is absent in the cells in which PARP2 was silenced. Apparently, the PARylation of NRF2 by PARP2 has pivotal role in regulating the subcellular (nuclear) localization of NRF2. The silencing of PARP2 rearranged the expression of genes encoding proteins with antioxidant function, among these a subset of NRF2-dependent genes.

Probing Oxidant Effects on Superoxide Dismutase 1 Oligomeric States in Live Cells Using Single-Molecule Fluorescence Anisotropy

The protein Cu/Zn superoxide dismutase (SOD1) is known to function as a dimer, but its concentration in cells (∼50 μM) and the dimerization constant (K d of 500 μM) results suggest that it exists in a monomer-dimer equilibrium. It is unclear how the oligomeric state of SOD1 changes when cells are initially exposed to high levels of extracellular oxidative stress. To address this problem, we introduced the single-molecule fluorescence anisotropy (smFA) assay to explore SOD1 oligomeric states in live COS7 cells. smFA specifically probes the fluorescence polarization changes caused by molecular rotations where the fast-rotating molecules (either due to smaller hydrodynamic volume or less viscous environments) deteriorate the emission polarization and thus lower the anisotropy. After validating that smFA is effective in distinguishing monomeric and dimeric fluorescence proteins, we overexpressed SOD1 in live COS7 cells and investigated how its oligomeric state changes under basal, 2 h, and 24 h 100 μM H2O2 treatments. We found that treating cells with H2O2 promotes SOD1 dimerization and decreases cellular viscosity in 2 h. Interestingly, prolonged H2O2 treatments show similar results as the basal conditions, indicating that cells return to a steady state similar to the basal state after 24 h, despite the presence of H2O2. Our results demonstrate that SOD1 changes its oligomeric state equilibrium in response to extracellular oxidative stresses. smFA will open new opportunities to explore the relationship between the SOD1 oligomer state and its H2O2-based signaling and transcription regulation roles.

An Exploratory Trial of EPI-589 in Amyotrophic Lateral Sclerosis (EPIC-ALS): Protocol for a Multicenter, Open-Labeled, 24-Week, Single-Group Study

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder, with its currently approved drugs, including riluzole and edaravone, showing limited therapeutic effects. Therefore, safe and effective drugs are urgently necessary. EPI-589 is an orally available, small-molecule, novel redox-active agent characterized by highly potent protective effects against oxidative stress with high blood-brain barrier permeability. Given the apparent oxidative stress and mitochondrial dysfunction involvement in the pathogenesis of ALS, EPI-589 may hold promise as a therapeutic agent.

OBJECTIVE

This protocol aims to describe the design and rationale for the EPI-589 Early Phase 2 Investigator-Initiated Clinical Trial for ALS (EPIC-ALS).

METHODS

EPIC-ALS is an explorative, open-labeled, single-arm trial that evaluates the safety and tolerability of EPI-589 in patients with ALS. This trial consists of 12-week run-in, 24-week treatment, and 4-week follow-up periods. Patients will receive 500 mg of EPI-589 3 times daily over the 24-week treatment period. Clinical assessments include the mean monthly change of Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised total score. The biomarkers are selected to analyze the effect on oxidative stress and neuronal damage. The plasma biomarkers are 8-hydroxy-2'-deoxyguanosine (8-OHdG), 3-nitrotyrosine (3-NT), neurofilament light chain (NfL), phosphorylated neurofilament heavy chain (pNfH), homocysteine, and creatinine. The cerebrospinal fluid biomarkers are 8-OHdG, 3-NT, NfL, pNfH, and ornithine. The magnetic resonance biomarkers are fractional anisotropy in the corticospinal tract and N-acetylaspartate in the primary motor area.

RESULTS

This trial began data collection in September 2021 and is expected to be completed in October 2023.

CONCLUSIONS

This study can provide useful data to understand the characteristics of EPI-589.

TRIAL REGISTRATION

Japan Primary Registries Network jRCT2061210031; tinyurl.com/2p84emu6.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/42032.

In Vitro Analysis of Biological Activity of Circulating Cell-Free DNA Isolated from Blood Plasma of Schizophrenic Patients and Healthy Controls-Part 2: Adaptive Response

Oxidized in vitro genomic DNA (gDNA) is known to launch an adaptive response in human cell cultures. The cfDNA extracted from the plasma of schizophrenic patients (sz-cfDNA) and healthy controls (hc-cfDNA) contains increased amounts of 8-oxodG, a DNA-oxidation marker. The aim of the research was answering a question: can the human cfDNA isolated from blood plasma stimulate the adaptive response in human cells? In vitro responses of ten human skin fibroblasts (HSFs) and four peripheral blood mononuclear cell (PBMC) lines after 1-24 h of incubation with sz-cfDNA, gDNA and hc-cfDNA containing different amounts of 8-oxodG were examined. Expressions of RNA of eight genes (NOX4, NFE2L2, SOD1, HIF1A, BRCA1, BRCA2, BAX and BCL2), six proteins (NOX4, NRF2, SOD1, HIF1A, γH2AX and BRCA1) and DNA-oxidation marker 8-oxodG were analyzed by RT-qPCR and flow cytometry (when analyzing the data, a subpopulation of lymphocytes (PBL) was identified). Adding hc-cfDNA or sz-cfDNA to HSFs or PBMC media in equal amounts (50 ng/mL, 1-3 h) stimulated transient synthesis of free radicals (ROS), which correlated with an increase in the expressions of NOX4 and SOD1 genes and with an increase in the levels of the markers of DNA damage γH2AX and 8-oxodG. ROS and DNA damage induced an antioxidant response (expression of NFE2L2 and HIF1A), DNA damage response (BRCA1 and BRCA2 gene expression) and anti-apoptotic response (changes in BAX and BCL2 genes expression). Heterogeneity of cells of the same HSFs or PBL population was found with respect to the type of response to (sz,hc)-cfDNA. Most cells responded to oxidative stress with an increase in the amount of NRF2 and BRCA1 proteins along with a moderate increase in the amount of NOX4 protein and a low amount of 8-oxodG oxidation marker. However, upon the exposure to (sz,hc)-cfDNA, the size of the subpopulation with apoptosis signs (high DNA damage degree, high NOX4 and low NRF2 and BRCA1 levels) also increased. No significant difference between the responses to sz-cfDNA and hc-cfDNA was observed. Sz-cfDNA and hc-cfDNA showed similarly high bioactivity towards fibroblasts and lymphocytes. Conclusion: In cultured human cells, hc-cfDNA and sz-cfDNA equally stimulated an adaptive response aimed at launching the antioxidant, repair, and anti-apoptotic processes. The mediator of the development of the adaptive response are ROS produced by, among others, NOX4 and SOD1 enzymes.

Computational Model of the Effect of Mitochondrial Dysfunction on Excitation–Contraction Coupling in Skeletal Muscle

It has become well established that mitochondria not only regulate myoplasmic calcium in skeletal muscle, but also use that calcium to stimulate oxidative phosphorylation (OXPHOS). While experimental approaches have allowed for imaging of mitochondrial calcium and membrane potentials in isolated fibers, capturing the role of mitochondria and the impact of mitochondrial impairments on excitation–contraction coupling (ECC) remains difficult to explore in intact muscle. Computational models have been widely used to examine the structure and function of skeletal muscle contraction; however, models of ECC to date lack communication between the myoplasm and mitochondria for regulating calcium and ATP during sustained contractions. To address this, a mathematical model of mitochondrial calcium handling and OXPHOS was integrated into a physiological model of ECC incorporating action potential propagation, calcium handling between the sarcoplasmic reticulum (SR) and the myoplasm, and crossbridge cycling. The model was used to examine the protective role of mitochondria during repeated stimulation and the impact of mitochondrial dysfunction on ECC resulting from progressive OXPHOS inhibition. Pathological myoplasmic calcium accumulation occurred through distinct mechanisms in the model in the case of either electron transport chain, F1F0 ATP synthase, or adenine nucleotide transporter impairments. To investigate the effect of each impairment on force, a model of calcium-stimulated apoptosis was utilized to capture dysfunction-induced reductions in muscle mass, driving whole muscle force loss. The model presented in this study can be used to examine the role of mitochondria in the regulation of calcium, ATP, and force generation during voluntary contraction.

DJ-1 Protein Inhibits Apoptosis in Cerebral Ischemia by Regulating the Notch1 and Nuclear Factor Erythroid2-Related Factor 2 Signaling Pathways

DJ-1 plays a neuroprotective role in cerebral ischemia- reperfusion (I/R) injury and participates in the apoptosis of brain nerve cells, but the underlying mechanism is unclear. We explored the molecular pathways underlying this role using in vivo and in vitro approaches. Middle cerebral artery occlusion- reperfusion (MCAO/R) rat models and oxygen- glucose deprivation- reoxygenation (OGD/R) HAPI cell cultures were used to simulate cerebral ischemia-reperfusion injury. The interaction between DJ-1 and Notch1 was enhanced after MCAO/R in rats. After treatment of rats with DJ-1 siRNA, the expression of Notch1 and Nrf2 was down-regulated, and apoptosis was promoted. In contrast, the DJ-1 based peptide ND-13 upregulated the expression of Notch1 and Nrf2, and prevented apoptosis. In vitro, the Notch1 signaling pathway inhibitor DAPT reversed the neuroprotective effect of ND-13 and promoted apoptosis, weakened the interaction between DJ-1 and Notch1, and decreased the expression of proteins in the Notch1 and Nrf2 pathways. Thus, we found that DJ-1 inhibits apoptosis by regulating the Notch1 signaling pathway and Nrf2 expression in cerebral I/R injury. These results imply that DJ-1 is a potential therapeutic target for cerebral I/R injury.

Redox profiles of amyotrophic lateral sclerosis lymphoblasts with or without known SOD1 mutations

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a fatal and rapidly progressing neurodegenerative disease that affects motor neurons. This disease is associated with oxidative stress especially in mutant superoxide dismutase 1 (mutSOD1) patients. However, less is known for the most prevalent sporadic ALS form, due to a lack of disease models. Here, we studied oxidative stress profiles in lymphoblasts from ALS patients with mutSOD1 or unknown (undSOD1) mutations.

METHODS

mutSOD1 and undSOD1 lymphoblasts, as well as sex/age-matched controls (3/group) were obtained from Coriell and divided into 46 years-old-men (C1), 46 years-old-women (C2) or 26/27 years-old-men (C3) cohorts. Growth curves were performed, and several parameters associated with redox homeostasis were evaluated, including SOD activity and expression, general oxidative stress levels, lipid peroxidation, response to oxidative stimulus, glutathione redox cycle, catalase expression, and activity, and Nrf2 transcripts. Pooled (all cohorts) and paired (intra-cohort) statistical analyses were performed, followed by clustering and principal component analyses (PCA).

RESULTS

Although a high heterogeneity among lymphoblast redox profiles was found between cohorts, clustering analysis based on 7 parameters with high chi-square ranking (total SOD activity, oxidative stress levels, catalase transcripts, SOD1 protein levels, metabolic response to mM concentrations of tert-butyl hydroperoxide, glutathione reductase activity, and Nrf2 transcript levels) provided a perfect cluster segregation between samples from healthy controls and ALS (undSOD1 and mutSOD1), also visualized in the PCA.

CONCLUSIONS

Our results show distinct redox signatures in lymphoblasts from mutSOD1, undSOD1 and healthy controls that can be used as therapeutic targets for ALS drug development.

Gene expression profiling in liver of zebrafish exposed to ethylhexyl methoxycinnamate and its photoproducts

In recent decades, the ecotoxicological potential of organic ultraviolet filters (OU-VFs) has received growing attention. However, the toxicity of its photoproducts or transformation products on freshwater vertebrates has been little explored. Therefore, the aim of the present study is to evaluate the possible adverse effects of ethylhexyl methoxycinnamate (EHMC) and its photoproducts [2-ethylhexanol (2-EH) and 4-methoxybenzaldehyde (4-MBA)] on the expression of stress-responsive and antioxidant genes. For this, zebrafish (Danio rerio) adults were exposed to pollutants at an environmentally relevant concentration (3 μg/L) and evaluated after 7, 14, and 21 days of exposure. The results of the principal component analysis (PCA) and two-way repeated measures (RM) ANOVA revealed that EHMC, 2-EH, and 4-MBA exposure caused significant downregulation of the genes hsp70, nrf2, cyp1a, ahr, sod1, sod2, cat, gstp1, gpx1a, gss, and gsr (on all trial days) in the liver of the animals. On the other hand, taken together, our data did not show significant differences between the effects induced by EHMC and its photoproducts. The genes evaluated in the present study play a major role in regulating the defensive antioxidant response against EHMC and its photoproducts. Additionally, our study provides an insight into the mechanisms of those OU-VFs in freshwater fish.

Antioxidant defense system in the prefrontal cortex of chronically stressed rats treated with lithium

Background

This study aimed to investigate the effects of lithium treatment on gene expression and activity of the prefrontal antioxidant enzymes: copper, zinc superoxide dismutase (SOD1), manganes superoxide dismutase (SOD2), catalase (CAT), and glutathione peroxidase (GPx) in animals exposed to chronic restraint stress (CRS).

Methods

The investigated parameters were quantified using real-time RT-PCR, Western blot analyses, and assays of enzyme activities.

Results

We found that lithium treatment decreased gene expression of SOD2, as well as the activities of SOD1 and SOD2 in chronically stressed rats to the levels found in unstressed animals. However, lithium treatment in animals exposed to CRS increased prefrontal GPx activity to the levels found in unstressed animals.

Conclusions

These findings confirm that treatment with lithium induced the modulation of prefrontal antioxidant status in chronically stressed rats. Our results may be very important in biomedical research for understanding the role of lithium in maintaining the stability of prefrontal antioxidant defense system in neuropsychiatric disorders caused by chronic stress.

Vitreous Humor Proteome: Targeting Oxidative Stress, Inflammation, and Neurodegeneration in Vitreoretinal Diseases

Oxidative stress is defined as an unbalance between pro-oxidants and antioxidants, as evidenced by an increase in reactive oxygen and reactive nitrogen species production over time. It is important in the pathophysiology of retinal disorders such as diabetic retinopathy, age-related macular degeneration, retinal detachment, and proliferative vitreoretinopathy, which are the focus of this article. Although the human organism's defense mechanisms correct autoxidation caused by endogenous or exogenous factors, this may be insufficient, causing an imbalance in favor of excessive ROS production or a weakening of the endogenous antioxidant system, resulting in molecular and cellular damage. Furthermore, modern lifestyles and environmental factors contribute to increased chemical exposure and stress induction, resulting in oxidative stress. In this review, we discuss the current information about oxidative stress and the vitreous proteome with a special focus on vitreoretinal diseases. Additionally, we explore therapies using antioxidants in an attempt to rescue the body from oxidation, restore balance, and maximize healthy body function, as well as new investigational therapies that have shown significant therapeutic potential in preclinical studies and clinical trial outcomes, along with their goals and strategic approaches to combat oxidative stress.

Polyphenols and Stem Cells for Neuroregeneration in Parkinson's Disease and Amyotrophic Lateral Sclerosis

Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS) are neurological disorders, pathologically characterized by chronic degeneration of dopaminergic neurons and motor neurons respectively. There is still no cure or effective treatment against the disease progression and most of the treatments are symptomatic. The present review offers an overview of the different factors involved in the pathogenesis of these diseases. Subsequently, we focused on the recent advanced studies of dietary polyphenols and stem cell therapies, which have made it possible to slow down the progression of neurodegeneration. To date, stem cells and different polyphenols have been used for the directional induction of neural stem cells into dopaminergic neurons and motor neurons. We have also discussed their involvement in the modulation of different signal transduction pathways and growth factor levels in various in vivo and in vitro studies. Likewise stem cells, polyphenols also exhibit the potential of neuroprotection by their anti-apoptotic, anti-inflammatory, anti-oxidant properties regulating the growth factors levels and molecular signaling events. Overall this review provides a detailed insight into recent strategies that promise the use of polyphenol with stem cell therapy for the possible treatment of PD and ALS.

NRF2 Activation and Downstream Effects: Focus on Parkinson's Disease and Brain Angiotensin

Reactive oxygen species (ROS) are signalling molecules used to regulate cellular metabolism and homeostasis. However, excessive ROS production causes oxidative stress, one of the main mechanisms associated with the origin and progression of neurodegenerative disorders such as Parkinson's disease. NRF2 (Nuclear Factor-Erythroid 2 Like 2) is a transcription factor that orchestrates the cellular response to oxidative stress. The regulation of NRF2 signalling has been shown to be a promising strategy to modulate the progression of the neurodegeneration associated to Parkinson's disease. The NRF2 pathway has been shown to be affected in patients with this disease, and activation of NRF2 has neuroprotective effects in preclinical models, demonstrating the therapeutic potential of this pathway. In this review, we highlight recent advances regarding the regulation of NRF2, including the effect of Angiotensin II as an endogenous signalling molecule able to regulate ROS production and oxidative stress in dopaminergic neurons. The genes regulated and the downstream effects of activation, with special focus on Kruppel Like Factor 9 (KLF9) transcription factor, provide clues about the mechanisms involved in the neurodegenerative process as well as future therapeutic approaches.

Antioxidant Effect of Hydroxytyrosol, Hydroxytyrosol Acetate and Nitrohydroxytyrosol in a Rat MPP+ Model of Parkinson's Disease

3,4-Dihydroxyphenyl ethanol, known as hydroxytyrosol (HTy), is a phenylpropanoid found in diverse vegetable species. Several studies have demonstrated that HTy is a potent antioxidant. Thus, our study is aimed to evaluate the antioxidant effect of HTy and its derivatives, hydroxytyrosol acetate (HTyA) and nitrohydroxytyrosol (HTyN), in a model of oxidative stress induced by 1-methyl-4-phenylpyridinium (MPP⁺) in rats. Rats were administered intravenously (i.v.) in the tail with 1 mL saline solution or polyphenol compound (1.5 mg/kg) 5 min before intrastriatal infusion of 10 µg MPP⁺/8 µL. We found that rats injured with MPP⁺, pretreatment with HTy, HTyA or HTyN significantly decreased ipsilateral turns. This result was consistent with a significant preservation of striatal dopamine levels and decreased lipid fluorescence products (LFP), a marker of oxidative stress. Brain GSH/GSSG ratio, from rats pretreated with HTy or HTyN showed a significant preservation of that marker, decreased as a consequence of MPP⁺-induced oxidative damage. These results show an antioxidant effect of HTy, HTyA and HTyN in the MPP⁺ model of Parkinson's disease in the rat.

Role of Oxidative Stress in the Pathogenesis of Amyotrophic Lateral Sclerosis: Antioxidant Metalloenzymes and Therapeutic Strategies

Amyotrophic lateral sclerosis (ALS) affects motor neurons in the cerebral cortex, brainstem and spinal cord and leads to death due to respiratory failure within three to five years. Although the clinical symptoms of this disease were first described in 1869 and it is the most common motor neuron disease and the most common neurodegenerative disease in middle-aged individuals, the exact etiopathogenesis of ALS remains unclear and it remains incurable. However, free oxygen radicals (i.e., molecules containing one or more free electrons) are known to contribute to the pathogenesis of this disease as they very readily bind intracellular structures, leading to functional impairment. Antioxidant enzymes, which are often metalloenzymes, inactivate free oxygen radicals by converting them into a less harmful substance. One of the most important antioxidant enzymes is Cu²⁺Zn²⁺ superoxide dismutase (SOD1), which is mutated in 20% of cases of the familial form of ALS (fALS) and up to 7% of sporadic ALS (sALS) cases. In addition, the proper functioning of catalase and glutathione peroxidase (GPx) is essential for antioxidant protection. In this review article, we focus on the mechanisms through which these enzymes are involved in the antioxidant response to oxidative stress and thus the pathogenesis of ALS and their potential as therapeutic targets.

Protective Effects of Pterostilbene on Lipopolysaccharide-Induced Acute Lung Injury in Mice by Inhibiting NF-κB and Activating Nrf2/HO-1 Signaling Pathways

Pterostilbene (PTER) is a kind of stilbene compound with biological activity isolated from plants such as red sandalwood, blueberry and grape. It has anti-tumor, anti-bacterial, anti-oxidation and other pharmacological activities. However, the underlying mechanism of the protective effect of PTER on lipopolysaccharide (LPS)-induced acute lung injury (ALI) remained not clarified. In this study, LPS was used to establish a mouse model of ALI. Bronchoalveolar lavage fluid (BALF) was collected for inflammatory cells, and the wet-to-dry weight ratio of the lungs was measured. The activities of myeloperoxidase (MPO), antioxidant indexes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and oxidation index such as malondialdehyde (MDA) in lung tissues of mice were measured by the corresponding kits. The levels of Cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), TNF-α, IL-6 and IL-1β in lung tissues of mice were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The activities of Nrf2, HO-1, p-p65 and p-IκB were determined by western blotting. The results showed that the model of LPS-induced ALI was successfully replicated, and it was found that PTER could significantly improve the pathological degree of ALI such as sustained the integrity of the lung tissue structure, alleviated pulmonary interstitial edema and alveolar wall thickening, reduced infiltrated inflammatory cells. PTER could decrease the number of inflammatory cells and obviously inhibit the increase of W/D ratio caused by LPS. PTER could also significantly reduce LPS-induced MPO and MDA, and increase LPS-decreased SOD, CAT and GSH-Px in the lungs. In addition, it was also found that PTER has the ability to decrease LPS-induced production of COX-2, iNOS, TNF-α, IL-6 and IL-1β. The underlying mechanism involved in the protective effect of PTER on ALI were via activating Nrf2 and HO-1, and inhibiting the phosphorylation of p65 and IκB. These results suggested that PTER can protect LPS-induced ALI in mice by inhibiting inflammatory response and oxidative stress, which provided evidence that PTER may be a potential therapeutic candidate for LPS-induced ALI intervention.

Protective Effect of Biobran/MGN-3 against Sporadic Alzheimer's Disease Mouse Model: Possible Role of Oxidative Stress and Apoptotic Pathways

Alzheimer's disease (AD) is a debilitating and irreversible brain disease that affects an increasing number of aged individuals, mandating the development of protective nutraceuticals. Biobran/MGN-3, an arabinoxylan from rice bran, has potent antioxidant, antiaging, and immunomodulatory effects. The aim of the present study was to investigate the protective effect of Biobran against sporadic Alzheimer's disease (SAD). SAD was induced in mice via intracerebroventricular injection of streptozotocin (STZ) (3 mg/kg). STZ-treated mice were administered with Biobran for 21 days. The effects of Biobran on memory and learning were measured via the Morris water maze, novel object recognition, and Y-maze tests. Biomarkers for apoptosis, oxidative stress, and amyloidogenesis were measured using ELISA and western blot analysis. Histopathological examination was performed to confirm neuronal damage and amyloid-beta deposition. Biobran reversed the spatial memory deficit in SAD-induced mice, and it increased the expression of glutathione, reduced malondialdehyde, decreased IL-6, decreased intercellular adhesion molecule-1 (ICAM-1), and significantly increased nuclear factor erythroid 2-related factor 2 (Nrf2) and antioxidant response element (ARE). Moreover, Biobran exerted a protective effect against amyloid-beta-induced apoptosis via the suppression of both cleaved caspase-3 and the proapoptotic protein Bax and via the upregulation of the antiapoptotic protein Bcl-2. Furthermore, it reduced the expression of forkhead box class O proteins. It could be concluded from this study that Biobran may be a useful nutritional antioxidant agent for protection against SAD through its activation of the gene expression of Nrf2/ARE, which in turn modulates the apoptotic and amyloidogenic pathways.

Chemical compounds with a neuroprotective effect from the seeds of Celosia argentea L

Oxidative stress plays a central role in the common pathophysiology of neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis, and Parkinson's disease. Antioxidant therapy has been suggested for the prevention and treatment of neurodegenerative diseases. Compounds derived from natural sources may offer the potential for new treatment options. Semen Celosiae is a traditional Chinese edible herbal medicine with a long history in China and exhibits wide-reaching biological activities such as hepatoprotective, anti-tumor, anti-diarrheal, anti-diabetic, anti-oxidant, etc. In this study, nine saponins and two phenylacetonitrile glycosides were isolated from Semen Celosiae and their structures were identified using ESI-MS and NMR techniques. Among them, compounds 1 and 2 have not been previously reported. The total concentrations of the five triterpenoid saponins and the two phenylacetonitrile glycosides were 3.348 mg g^-1 and 0.187 mg g^-1, respectively, suggesting that Semen Celosiae is a novel viable source of the two kinds of compounds. These compounds were observed to significantly attenuate t-BHP-induced neuronal damage by effectively enhancing cell viability and decreasing reactive oxygen species generation and cell apoptosis rate in NSC-34 cells. Furthermore, compounds 1 and 7 reduced the ratios of cleaved caspase-3: caspase-3 and cleaved caspase-7: caspase-7 and the level of cytochrome C, while they increased the levels of SOD1 and Beclin 1. These findings suggest that compounds 1-11 are potent inhibitors of neuron injury elicited by t-BHP, possibly via inhibition of oxidative stress and apoptosis, and activation of autophagy; therefore they may be valuable leads for future therapeutic development.

Peripheral Blood NRF2 Expression as a Biomarker in Human Health and Disease

Nuclear factor erythroid 2-related factor 2 (NRF2), a transcription factor which plays a critical role in maintenance of cellular redox, has been identified as a therapeutic target in a number of human diseases. Several reports have demonstrated beneficial effects of NRF2 manipulation in animal models of disease, and one NRF2-activating drug, dimethyl fumarate, is already approved for the treatment of multiple sclerosis. However, drug discovery is slowed due to a dearth of biomarkers which can inform target engagement and magnitude and duration of action. Peripheral blood mononuclear cells (PBMCs) are an accessible, minimally-invasive source of biomarkers which can be readily assayed and objectively monitored as a surrogate endpoint of NRF2 activation in clinical trials. We undertook a review of the literature on PBMC NRF2 measurements in human studies to explore its role as a suitable biomarker in various contexts of health and disease. It is clear that NRF2 and its target genes can be readily assayed from PBMCs in multiple disease contexts and may track with disease progression. Further work needs to be undertaken to evaluate its stability but should be considered as an exploratory marker in clinical trials targeting NRF2 activation.

Tetramethylpyrazine nitrone improves motor dysfunction and pathological manifestations by activating the PGC-1α/Nrf2/HO-1 pathway in ALS mice

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by progressive loss of upper and lower motor neurons that results in skeletal muscle atrophy, weakness and paralysis. Oxidative stress plays a key role in the pathogenesis of ALS, including familial forms of the disease arising from mutation of the gene coding for superoxide dismutase (SOD1). We have used the SOD1^G93A ALS mouse model to investigate the efficacy of 2-[[(1,1-dimethylethyl)oxidoimino]-methyl]-3,5,6-trimethylpyrazine (TBN), a novel tetramethylpyrazine derivative armed with a powerful free-radical scavenging nitrone moiety. TBN was administered to mice by intraperitoneal or intragastric injection after the onset of motor deficits. TBN slowed the progression of motor neuron disease as evidenced by improved motor performance, reduced spinal motor neuron loss and the associated glial response, and decreased skeletal muscle fiber denervation and fibrosis. TBN treatment activated mitochondrial antioxidant activity through the PGC-1α/Nrf2/HO-1 pathway and decreased the expression of human SOD1. These findings suggest that TBN holds promise as a therapeutic agent for ALS.

Natural compounds against doxorubicin-induced cardiotoxicity: A review on the involvement of Nrf2/ARE signaling pathway

Cardiotoxicity is the main concern for long-term use of the doxorubicin (DOX). Reactive oxygen species (ROS) generation leads to oxidative stress that significantly contributes to the cardiac damage induced by DOX. The nuclear factor erythroid 2-related factor (Nrf2) acts as a protective player against DOX-induced myocardial oxidative stress. Several natural compounds (NCs) with anti-oxidative effects, were examined to suppress DOX cardiotoxicity such as asiatic acid, α-linolenic acid, apigenin, baicalein, β-lapachone, curdione, dioscin, ferulic acid, Ganoderma lucidum polysaccharides, genistein, ginsenoside Rg3, indole-3-carbinol, naringenin-7-O-glucoside, neferine, p-coumaric acid, pristimerin, punicalagin, quercetin, sulforaphane, and tanshinone IIA. The present article, reviews NCs that showed protective effects against DOX-induced cardiac injury through induction of Nrf2 signaling pathway.

Foods with Potential Prooxidant and Antioxidant Effects Involved in Parkinson's Disease

Oxidative stress plays a fundamental role in the pathogenesis of Parkinson's disease (PD). Oxidative stress appears to be responsible for the gradual dysfunction that manifests via numerous cellular pathways throughout PD progression. This review will describe the prooxidant effect of excessive consumption of processed food. Processed meat can affect health due to its high sodium content, advanced lipid oxidation end-products, cholesterol, and free fatty acids. During cooking, lipids can react with proteins to form advanced end-products of lipid oxidation. Excessive consumption of different types of carbohydrates is a risk factor for PD. The antioxidant effects of some foods in the regular diet provide an inconclusive interpretation of the environment's mechanisms with the modulation of oxidation stress-induced PD. Some antioxidant molecules are known whose primary mechanism is the neuroprotective effect. The melatonin mechanism consists of neutralizing reactive oxygen species (ROS) and inducing antioxidant enzyme's expression and activity. N-acetylcysteine protects against the development of PD by restoring levels of brain glutathione. The balanced administration of vitamin B3, ascorbic acid, vitamin D and the intake of caffeine every day seem beneficial for brain health in PD. Excessive chocolate intake could have adverse effects in PD patients. The findings reported to date do not provide clear benefits for a possible efficient therapeutic intervention by consuming the nutrients that are consumed regularly.

Regenerative Therapy for Osteoarthritis: A Perspective

Osteoarthritis (OA) is the most common type of arthritis and causes a significant deterioration in patients’ quality of life. The high prevalence of OA as well as the current lack of disease-modifying drugs led to a rise in regenerative medicine efforts. The hope is that this will provide a treatment modality with the ability to alter the course of OA via structural modifications of damaged articular cartilage (AC). Regenerative therapy in OA starts with the concept that administered cells may engraft to a lesion site and differentiate into chondrocytes. However, recent studies show that cells, particularly when injected in suspension, rapidly undergo apoptosis after exerting a transient paracrine effect. If the injected stem cells do not lead to structural improvements of a diseased joint, the high cost of cell therapy for OA cannot be justified, particularly when compared with other injection therapeutics such as corticosteroids and hyaluronic acid. Long-term survival of implanted cells that offer prolonged paracrine effects or possible engraftment is essential for a successful cell therapy that will offer durable structural improvements. In this perspective review, the history and current status of regenerative therapy in OA are summarized along with the conceptual strategy and future directionsfor a successful regenerative therapy that can provide structural modifications in OA.

Exercise-Related Oxidative Stress as Mechanism to Fight Physical Dysfunction in Neuromuscular Disorders

Neuromuscular diseases (NMDs) are a group of often severely disabling disorders characterized by dysfunction in one of the main constituents of the motor unit, the cardinal anatomic-functional structure behind force and movement production. Irrespective of the different pathogenic mechanisms specifically underlying these disease conditions genetically determined or acquired, and the related molecular pathways involved in doing that, oxidative stress has often been shown to play a relevant role within the chain of events that induce or at least modulate the clinical manifestations of these disorders. Due to such a putative relevance of the imbalance of redox status occurring in contractile machinery and/or its neural drive in NMDs, physical exercise appears as one of the most important conditions able to positively interfere along an ideal axis, going from a deranged metabolic cell homeostasis in motor unit components to the reduced motor performance profile exhibited by the patient in everyday life. If so, it comes out that it would be important to identify a proper training program, suitable for load and type of exercise that is able to improve motor performance in adaptation and response to such a homeostatic imbalance. This review therefore analyzes the role of different exercise trainings on oxidative stress mechanisms, both in healthy and in NMDs, also including preclinical studies, to elucidate at which extent these can be useful to counteract muscle impairment associated to the disease, with the final aim of improving physical functions and quality of life of NMD patients.

Depletion of brain perivascular macrophages regulates acute restraint stress-induced neuroinflammation and oxidative/nitrosative stress in rat frontal cortex

The central nervous system can respond to peripheral immune stimuli through the activation of the neurovascular unit. One of the cellular types implicated are perivascular macrophages (PVMs), hematopoietic-derived brain-resident cells located in the perivascular space. PVMs have been implicated in the immune surveillance and in the regulation of the accumulation/trafficking of macromolecules in brain-blood interfaces. Recent studies suggested that the role of PVMs could vary depending on the nature and duration of the immune challenge applied. Here, we investigate the role of PVMs in stress-induced neuroinflammation and oxidative/nitrosative consequences. The basal phagocytic activity of PVMs was exploited to selectively deplete them by ICV injection of liposomes encapsulating the pro-apoptotic drug clodronate. Acute restraint stress-induced neuroinflammation and oxidative/nitrosative stress in rat brain frontal cortex samples were assessed by western blot and RT-PCR analyses. The depletion of PVMs: (1) decreased tumor necrosis-α levels (2) prevented the Janus kinase/signal transducers and activators of transcription pathway and increased interleukin-6 receptor protein-expression in stress conditions; (3) prevented the stress-induced Toll-like receptor 4/Myeloid differentiation primary response 88 protein signaling pathway; (4) down-regulated the pro-inflammatory nuclear factor κB/cyclooxygenase-2 pathway; (5) prevented stress-induced lipid peroxidation and the concomitant increase of the endogenous antioxidant mediators nuclear factor (erythroid-derived 2)-like 2, glutathione reductase 1 and Parkinsonism-associated deglycase mRNA expression. Our results point to PVMs as regulators of stress-induced neuroinflammation and oxidative/nitrosative stress. Much more scientific effort is still needed to evaluate whether their selective manipulation is promising as a therapeutic strategy for the treatment of stress-related neuropsychopathologies.

Paeonol protects against testicular ischaemia-reperfusion injury in rats through inhibition of oxidative stress and inflammation

Ischaemia-reperfusion (IR) is the most common form of testicular injury that results in oxidative damage and inflammation ending by subinfertility. Paeonol, a natural phenolic compound, exhibits antioxidant and anti-inflammatory effects. Thus, the present study investigated the role of paeonol in rat testicular IR injury. Thirty adult Wistar rats were randomly divided into five groups; sham, sham treated with paeonol, IR injury, and IR pre-treated with paeonol at low and high doses. Serum testosterone and testicular levels of malondialdehyde and reduced glutathione (GSH) besides superoxide dismutase (SOD) activity were determined. Gene quantifications for tumour necrosis factor-α (TNF-α), hypoxia-inducible factor-1α (HIF-1α) and heat shock protein 70 (HSP70) were also assessed. Histopathological pictures and the immunohistochemical expression of testicular nuclear factor erythroid 2-related factor 2 (Nrf2), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were shown. Pre-treatment with paeonol prevented the drop in serum testosterone, alongside with improvement of testicular malondialdehyde and GSH levels plus SOD activity. Paeonol regained the normal spermatogenesis with prevention of IR-induced increase in TNF-α, HIF-1α and HSP70 gene expression besides IL-1β and IL-6 immunostaining and reduction in Nrf2 protein expression. Paeonol exerted a dose-dependent beneficial effect on testicular IR injury. This effect was achieved by its antioxidant and anti-inflammatory effects.

ALS skin fibroblasts reveal oxidative stress and ERK1/2-mediated cytoplasmic localization of TDP-43

The main hallmark of many forms of familiar and sporadic amyotrophic lateral sclerosis (ALS) is a reduction in nuclear TDP-43 protein and its inclusion in cytoplasmic aggregates in motor neurons. In order to understand which cellular and molecular mechanisms underlie the mislocalization of TDP-43, we examined human skin fibroblasts from two individuals with familial ALS, both with mutations in TDP-43, and two individuals with sporadic ALS, both without TDP-43 mutations or mutations in other ALS related genes. We found that all ALS fibroblasts had a partially cytoplasmic localization of TDP-43 and had reduced cell metabolism as compared to fibroblasts from apparently healthy individuals. ALS fibroblasts showed an increase in global protein synthesis and an increase in 4E-BP1 and rpS6 phosphorylation, which is indicative of mTORC1 activity. We also observed a decrease in glutathione (GSH), which suggests that oxidative stress is elevated in ALS. ERK1/2 activity regulated the extent of oxidative stress and the localization of TDP-43 in the cytoplasm in all ALS fibroblasts. Lastly, ALS fibroblasts showed reduced stress granule formation in response to H₂O₂ stress. In conclusion, these findings identify specific cellular and molecular defects in ALS fibroblasts, thus providing insight into potential mechanisms that may also occur in degenerating motor neurons.

Mice With a Combined Deficiency of Superoxide Dismutase 1 (Sod1), DJ-1 (Park7), and Parkin (Prkn) Develop Spontaneous Retinal Degeneration With Aging

Purpose

Chronic oxidative stress is an important mechanism of disease in aging disorders. We do not have a good model to recapitulate AMD and other retinal disorders in which chronic oxidative stress plays an important role. We hypothesized that mice with a combined deficiency in superoxide dismutase 1 (Sod1), DJ-1 (Park-7), and Parkin (Prkn) (triple knock out, TKO) would have an increased level of chronic oxidative stress in the retina, with anatomic and functional consequences just with aging.

Methods

Eyes of TKO and B6J control mice were (1) monitored with optical coherence tomography (OCT) and electroretinography (ERG) over time, and (2) collected for oxidative marker protein analysis by ELISA or immunohistochemistry and for transmission electron microscopy studies.

Results

TKO mice developed qualitative disruptions in outer retinal layers in OCT by 3 months, increased accumulation of fundus spots and subretinal microglia by 6 months of age, significant retinal thinning by 9 months, and decreased ERG signal by 12 months. Furthermore, we found increased accumulation of the oxidative marker malondialdehyde (MDA) in the retina and increased basal laminal deposits (BLD) and mitochondria number and size in the retinal pigment epithelium of aging TKO mice.

Conclusions

TKO mice can serve as a platform to study retinal diseases that involve chronic oxidative stress, including macular degeneration, retinal detachment, and ischemic retinopathies. In order to model each of these diseases, additional disease-specific catalysts or triggers could be superimposed onto the TKO mice. Such studies could provide better insight into disease mechanisms and perhaps lead to new therapeutic approaches.

Senile Osteoporosis: The Involvement of Differentiation and Senescence of Bone Marrow Stromal Cells

Senile osteoporosis has become a worldwide bone disease with the aging of the world population. It increases the risk of bone fracture and seriously affects human health. Unlike postmenopausal osteoporosis which is linked to menopause in women, senile osteoporosis is due to aging, hence, affecting both men and women. It is commonly found in people with more than their 70s. Evidence has shown that with age increase, bone marrow stromal cells (BMSCs) differentiate into more adipocytes rather than osteoblasts and undergo senescence, which leads to decreased bone formation and contributes to senile osteoporosis. Therefore, it is necessary to uncover the molecular mechanisms underlying the functional changes of BMSCs. It will benefit not only for understanding the senile osteoporosis development, but also for finding new therapies to treat senile osteoporosis. Here, we review the recent advances of the functional alterations of BMSCs and the related mechanisms during senile osteoporosis development. Moreover, the treatment of senile osteoporosis by aiming at BMSCs is introduced.

Rapamycin Induced Autophagy Inhibits Inflammation-Mediated Endplate Degeneration by Enhancing Nrf2/Keap1 Signaling of Cartilage Endplate Stem Cells

Cartilage endplate (CEP) calcification inhibits the transport of metabolites and nutrients in the intervertebral disk and is an important initiating factor of intervertebral disk degeneration. However, the mechanisms governing CEP degeneration have not been thoroughly elucidated. In this study, we established a mouse CEP degeneration model and showed that autophagy insufficiency caused the degeneration of CEP. We found that the inflammatory cytokine tumor necrosis factor-α (TNF-α) increased the level of intracellular reactive oxygen species (ROS) and caused cell senescence and osteogenic differentiation of cartilage endplate stem cells (CESCs), whereas rapamycin-induced autophagy protected CESCs from TNF-α-induced oxidative stress and cell senescence. Furthermore, rapamycin-induced autophagy helped CESCs maintain the chondrogenic properties and inhibited extracellular matrix protease expression and osteogenic differentiation. Further study revealed that autophagy activated by rapamycin or inhibited by chloroquine influenced the expression and nuclear translocation of Nrf2, thereby controlling the expression of antioxidant proteins and the scavenging of ROS. Taken together, the results indicate that rapamycin-induced autophagy enhances Nrf2/Keap1 signaling and promotes the expression of antioxidant proteins, thereby eliminating ROS, alleviating cell senescence, reducing the osteogenic differentiation of CESCs, and ultimately protecting CEPs from chronic inflammation-induced degeneration. Stem Cells 2019;37:828-840.

Modulation of Hippocampal Antioxidant Defense System in Chronically Stressed Rats by Lithium

This study examined the effects of lithium on gene expression and activity of the antioxidant enzymes copper zinc superoxide dismutase (SOD1), manganese superoxide dismutase (SOD2), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) in the hippocampus of chronically stressed rats. In addition, we examined the effects of lithium on anxiety behaviors, hippocampal concentrations of dopamine (DA) and malondialdehyde (MDA), protein levels of brain-derived neurotrophic factor (BDNF), tyrosine hydroxylase (TH), dopamine transporter (DAT), and catechol-O-methyltransferase (COMT), as well as activity of monoamine oxidase (MAO) in chronically stressed rats. The investigated parameters were quantified by real-time RT-PCR, Western blot analyses, and assays of enzyme activities. We found that lithium did not change gene expression of SOD1, CAT, GPx, and GR but decreased gene expression of SOD2 in chronically stressed rats. A very important result in this study was that lithium treatment decreased the enzyme activities of SOD1 and SOD2 but increased the enzyme activities of GPx and GR in stress condition, which indicates the control of redox balance. The reduced concentration of MDA confirms this. In addition, we found that lithium treatment decreased high protein levels of BDNF and DAT in chronically stressed rats to the level found in unstressed animals. Also, lithium treatment increased the expression of TH but decreased the enzyme activity of MAO B, which contributed to the increase of hippocampal concentration of DA in chronically stressed rats to the level of unstressed animals. Finally, lithium treatment in animals exposed to chronic stress increased the time spent in open arms. Lithium-induced modulation of hippocampal antioxidant status and attenuation of oxidative stress stabilized behavior in animals with high anxiety index. In addition, reduced oxidative stress was followed by the changes of both turnover of DA and levels of BDNF protein in chronically stressed rats treated with lithium. These findings may be important in preclinical research of the effects of lithium on oxidative stress level in pathological conditions.

Dimethyl fumarate, a two-edged drug: Current status and future directions

Dimethyl fumarate (DMF) is a fumaric acid ester registered for the treatment of relapsing-remitting multiple sclerosis (RRMS). It induces protein succination leading to inactivation of cysteine-rich proteins. It was first shown to possess cytoprotective and antioxidant effects in noncancer models, which appeared related to the induction of the nuclear factor erythroid 2 (NF-E2)-related factor 2 (NRF2) pathway. DMF also displays antitumor activity in several cellular and mice models. Recently, we showed that the anticancer mechanism of DMF is dose-dependent and is paradoxically related to the decrease in the nuclear translocation of NRF2. Some other studies performed indicate also the potential role of DMF in cancers, which are dependent on the NRF2 antioxidant and cellular detoxification program, such as KRAS-mutated lung adenocarcinoma. It, however, seems that DMF has multiple biological effects as it has been shown to also inhibit the transcription factor nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), thus blocking downstream targets that may be involved in the development and progression of inflammatory cascades leading to various disease processes, including tumors, lymphomas, diabetic retinopathy, arthritis, and psoriasis. Herein, we present the current status and future directions of the use of DMF in various diseases models with particular emphases on its targeting of specific intracellular signal transduction cascades in cancer; to shed some light on its possible mode of action.

When safeguarding goes wrong: Impact of oxidative stress on protein homeostasis in health and neurodegenerative disorders

Cellular redox status is an established player in many different cellular functions. The buildup of oxidants within the cell is tightly regulated to maintain a balance between the positive and negative outcomes of cellular oxidants. Proteins are highly sensitive to oxidation, since modification can cause widespread unfolding and the formation of toxic aggregates. In response, cells have developed highly regulated systems that contribute to the maintenance of both the global redox status and protein homeostasis at large. Changes to these systems have been found to correlate with aging and age-related disorders, such as neurodegenerative pathologies. This raises intriguing questions as to the source of the imbalance in the redox and protein homeostasis systems, their interconnectivity, and their role in disease progression. Here we focus on the crosstalk between the redox and protein homeostasis systems in neurodegenerative diseases, specifically in Alzheimer's, Parkinson's, and ALS. We elaborate on some of the main players of the stress response systems, including the master regulators of oxidative stress and the heat shock response, Nrf2 and Hsf1, which are essential features of protein folding, and mediators of protein turnover. We illustrate the elegant mechanisms used by these components to provide an immediate response, including protein plasticity controlled by redox-sensing cysteines and the recruitment of naive proteins to the redox homeostasis array that act as chaperons in an ATP-independent manner.

Activation of Nrf2/ARE pathway alleviates the cognitive deficits in PS1V97L-Tg mouse model of Alzheimer's disease through modulation of oxidative stress

Oxidative stress refers to an imbalance between oxidative and antioxidative systems due to environmental factors. Although oxidative stress is implicated in the pathogenesis of Alzheimer's disease (AD), its precise role is not yet understood. We aimed to investigate the pathogenic mechanisms of the oxidative stress by using in vitro cultured neurons and in vivo AD models of PS1V97L-transgenic (Tg) mice. Our results showed that when oxidative stress became increasingly evident, the endogenous protective pathway of nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) decreased in 10-month-old PS1V97L-Tg mice. Activating the Nrf2/ARE pathway suppressed oxidative stress, decreased amyloid-β (Aβ), and improved the cognitive function of the PS1V97L-Tg mice. In contrast, blocking the Nrf2/ARE pathway augmented oxidative injury and decreased the cell viability of PS1V97L-Tg neurons. Our results highlight the role of the Nrf2/ARE pathway in regulating oxidative stress of the PS1V97L-Tg mice and may indicate a potential therapeutic avenue for AD treatment.

pLG72 induces superoxide radicals via interaction and aggregation with SOD1

G72 has been characterised as a susceptibility gene that can have wide-ranging effects in a number of neurodegenerative diseases, including schizophrenia and major depression. Indeed, its product, pLG72, is a potential serum biomarker for schizophrenia. Previous transcriptomic and biochemical studies have indicated that pLG72 may induce the production of mitochondrial reactive oxygen species (ROS), resulting in cell damage. Here, we investigated the mechanism of pLG72 by transfecting a human U87 glioblastoma cell line with a G72 construct. By employing ROS-specific scavengers, we discovered that superoxide radicals were specifically induced in the pLG72-expressing cells. We also found that pLG72 interacted and co-localised with superoxide dismutase 1 (SOD1), resulting in aggregation of SOD1 with a concomitant 23% or 74% reduction of total SOD activity, depending on the amount of G72 transfection plasmid. Finally, we found that transfection of U87 cells with the G72 construct caused a 29% decrease in cell proliferation. The observed loss of SOD1 function in pLG72-expressing cells may explain the elevated ROS levels and inhibition of U87 cell proliferation and has implications for understanding the onset of neurodegenerative diseases in humans.

LncRNA MT1DP Aggravates Cadmium-Induced Oxidative Stress by Repressing the Function of Nrf2 and is Dependent on Interaction with miR-365

Although cadmium (Cd)-induced hepatoxicity is well established, pronounced knowledge gaps remain existed regarding the inherent cellular signaling that dictates Cd toxicity. Specifically, the molecular basis for determining the equilibrium between prosurvival and proapoptotic signaling remains poorly understood. Thus, it is recently revealed that long non-coding RNA (lncRNA) MT1DP, a pseudogene in the metallothionein (MT) family, promoted Cd-induced cell death through activating the RhoC-CCN1/2-AKT pathway and modulating MT1H induction. Here, first the dependency of MT1DP induction on MTF1, an important transcriptional factor in driving the mRNA expression of MT1 members is defined. Additionally, a bridge molecule between MT1DP and nuclear factor erythroid 2-related factor 2 (Nrf2) is established: miR-365. Mechanistically, MT1DP induction under Cd stress decreases the nuclear factor erythroid 2-related factor 2 (Nrf2) level to evoke oxidative stress through the elevation of miR-365, which acted to repress the Nrf2 level via direct binding to its 3'UTR. In contrast to the competing endogenous RNA (ceRNA) mechanism, a new mechanism is proposed: MT1DP elevated the miR-365 level though stabilizing its RNA via direct binding. Collectively, the combined data demonstrate a crucial role of MT1DP in reducing the Nrf2-mediated protection of cells, and this is dependent on the interplay with miR-365. Hence, the study further expands the knowledge of inducible endogenous lncRNA in modulating oxidative stress.

Elevated levels of 8-OHdG and PARK7/DJ-1 in peri-implantitis mucosa

BACKGROUND

Reactive oxygen species contribute to periodontal tissue homeostasis under control of anti-oxidative responses. Disruption in this balance induces severe inflammation and extended tissue degradation.

PURPOSE

Aim of this study was to identify the expression levels of nuclear factor, erythroid 2 like 2 (NFE2L2/NRF2), Parkinsonism associated deglycase (PARK7/DJ-1), kelch-like ECH associated protein 1 (KEAP1), and 8-hydroxy-deoxyguanosine (8-OHdG) in peri-implant mucosal tissues affected by peri-implantitis, and to compare the levels to those of periodontally diseased and healthy tissue samples.

METHODS

Tissue biopsies were collected from systemically healthy, non-smoking 12 peri-implantitis patients, 13 periodontitis patients, and 13 periodontally healthy controls. Expression levels of NFE2L2/NRF2, PARK7/DJ-1, KEAP1, and 8-OHdG in tissue samples were analyzed immunohistochemically. Statistical analysis was performed by one-way ANOVA with Tukey's HSD test.

RESULTS

Inflammatory cell infiltration in the connective tissue and loss of architecture in the spinous layer of the epithelium were prominent in peri-implantitis. Proportions of 8-OHdG and PARK7/DJ-1 expressing cells were elevated in both peri-implantitis (P = .025 for 8-OHdG and P = .014 for PARK7/DJ-1) and periodontitis (P = .038 for 8-OHdG and P = .012 for PARK7/DJ-1) groups in comparison with controls. Staining intensities of 8-OHdG and PARK7/DJ-1 were higher in the periodontitis and peri-implantitis groups than in the control (P < .01) groups. There was no difference in the expression levels of NFE2L2/NRF2 between the groups. KEAP1 was not observed in any tissue sample.

CONCLUSIONS

Peri-implantitis is characterized by severe inflammation and architectural changes in the epithelium and connective tissue. The expressions of 8-OHdG and PARK7/DJ-1 are elevated in both peri-implantitis and periodontitis.

Melatonin and tumeric ameliorate aging-induced changes: implication of immunoglobulins, cytokines, DJ-1/NRF2 and apoptosis regulation

Aging is associated with several biological, physiological, cellular and histological changes. In the present study, we investigated the effect of aging on different signaling pathways, including antioxidant system, apoptosis and immune status. Several natural products were used to ameliorate and block aging-related changes. Melatonin and turmeric have been known to ameliorate and decrease aging-related changes. However, the exact mechanism(s) of their action is not fully understood. In the present study, we tried to uncover the regulatory mechanism(s) by which melatonin and turmeric work against aging. We found that aging differentially regulated blood serum immunoglobulins; increased IgA and decreased IgE. Furthermore, all the serum cytokines investigated (TNF-α, IFN-γ, IL-6 and IL-8) were highly increased by aging. In addition, the antioxidant upstream regulators; DJ-1 and NRF2 were markedly repressed with aging in thymus tissues. We also found that aging induced apoptosis promoting genes p53 and Bax mRNA in thymus tissues. Finally, we found clear histological changes in thymus and spleen tissues. Administration of either melatonin or tumeric clearly ameliorated and blocked to some extinct the effect of aging. Altogether, aging was associated with downregulation of antioxidant regulators; DJ-1 and NRF2, promoted apoptosis and induced changes in the immune status. Furthermore, melatonin and tumeric markedly reversed the action of aging through activating DJ-1/NRF2 signaling pathway and inhibiting p53/Bax apoptotic pathway.

DJ-1 based peptide, ND-13, promote functional recovery in mouse model of focal ischemic injury

Stroke is a leading cause of death worldwide and inflicts serious long-term damage and disability. The vasoconstrictor Endothelin-1, presenting long-term neurological deficits associated with excitotoxicity and oxidative stress is being increasingly used to induce focal ischemic injury as a model of stroke. A DJ-1 based peptide named ND-13 was shown to protect against glutamate toxicity, neurotoxic insults and oxidative stress in various animal models. Here we focus on the benefits of treatment with ND-13 on the functional outcome of focal ischemic injury. Wild type C57BL/6 mice treated with ND-13, after ischemic induction in this model, showed significant improvement in motor function, including improved body balance and motor coordination, and decreased motor asymmetry. We found that DJ-1 knockout mice are more sensitive to Endothelin-1 ischemic insult than wild type mice, contributing thereby additional evidence to the widely reported relevance of DJ-1 in neuroprotection. Furthermore, treatment of DJ-1 knockout mice with ND-13, following Endothelin-1 induced ischemia, resulted in significant improvement in motor functions, suggesting that ND-13 provides compensation for DJ-1 deficits. These preliminary results demonstrate a possible basis for clinical application of the ND-13 peptide to enhance neuroprotection in stroke patients.

Meta-Analysis of Parkinson's Disease and Alzheimer's Disease Revealed Commonly Impaired Pathways and Dysregulation of NRF2-Dependent Genes

Many lines of evidence suggest that Parkinson's disease (PD) and Alzheimer's disease (AD) have common characteristics, such as mitochondrial dysfunction and oxidative stress. As the underlying molecular mechanisms are unclear, we perform a meta-analysis with 9 microarray datasets of PD studies and 7 of AD studies to explore it. Functional enrichment analysis revealed that PD and AD both showed dysfunction in the synaptic vesicle cycle, GABAergic synapses, phagosomes, oxidative phosphorylation, and TCA cycle pathways, and AD had more enriched genes. Comparing the differentially expressed genes between AD and PD, we identified 54 common genes shared by more than six tissues. Among them, 31 downregulated genes contained the antioxidant response element (ARE) consensus sequence bound by NRF2. NRF2 is a transcription factor, which protects cells against oxidative stress through coordinated upregulation of ARE-driven genes. To our surprise, although NRF2 was upregulated, its target genes were all downregulated. Further exploration found that MAFF was upregulated in all tissues and significantly negatively correlated with the 31 NRF2-dependent genes in diseased conditions. Previous studies have demonstrated over-expressed small MAFs can form homodimers and act as transcriptional repressors. Therefore, MAFF might play an important role in dysfunction of NRF2 regulatory network in PD and AD.