Redox Dysregulation Research Articles

Redox Control in Acute Lymphoblastic Leukemia: From Physiology to Pathology and Therapeutic Opportunities.

Acute lymphoblastic leukemia (ALL) is a hematological malignancy originating from B- or T-lymphoid progenitor cells. Recent studies have shown that redox dysregulation caused by overproduction of reactive oxygen species (ROS) has an important role in the development and progression of leukemia. The application of pro-oxidant therapy, which targets redox dysregulation, has achieved satisfactory results in alleviating the conditions of and improving the survival rate for patients with ALL. However, drug resistance and side effects are two major challenges that must be addressed in pro-oxidant therapy. Oxidative stress can activate a variety of antioxidant mechanisms to help leukemia cells escape the damage caused by pro-oxidant drugs and develop drug resistance. Hematopoietic stem cells (HSCs) are extremely sensitive to oxidative stress due to their low levels of differentiation, and the use of pro-oxidant drugs inevitably causes damage to HSCs and may even cause severe bone marrow suppression. In this article, we reviewed research progress regarding the generation and regulation of ROS in normal HSCs and ALL cells as well as the impact of ROS on the biological behavior and fate of cells. An in-depth understanding of the regulatory mechanisms of redox homeostasis in normal and malignant HSCs is conducive to the formulation of rational targeted treatment plans to effectively reduce oxidative damage to normal HSCs while eradicating ALL cells.

Redox Dysregulation, Myelination Deficit and Dysconnectivity in Schizophrenia: A Translational Study in First Episode Patients and Experimental Models

Redox Dysregulation, Myelination Deficit and Dysconnectivity in Schizophrenia: A Translational Study in First Episode Patients and Experimental Models

Interplay Between Reactive Oxygen/Reactive Nitrogen Species and Metabolism in Vascular Biology and Disease.

Reactive oxygen species (ROS; e.g., superoxide [O2•-] and hydrogen peroxide [H2O2]) and reactive nitrogen species (RNS; e.g., nitric oxide [NO•]) at the physiological level function as signaling molecules that mediate many biological responses, including cell proliferation, migration, differentiation, and gene expression. By contrast, excess ROS/RNS, a consequence of dysregulated redox homeostasis, is a hallmark of cardiovascular disease. Accumulating evidence suggests that both ROS and RNS regulate various metabolic pathways and enzymes. Recent studies indicate that cells have mechanisms that fine-tune ROS/RNS levels by tight regulation of metabolic pathways, such as glycolysis and oxidative phosphorylation. The ROS/RNS-mediated inhibition of glycolytic pathways promotes metabolic reprogramming away from glycolytic flux toward the oxidative pentose phosphate pathway to generate nicotinamide adenine dinucleotide phosphate (NADPH) for antioxidant defense. This review summarizes our current knowledge of the mechanisms by which ROS/RNS regulate metabolic enzymes and cellular metabolism and how cellular metabolism influences redox homeostasis and the pathogenesis of disease. A full understanding of these mechanisms will be important for the development of new therapeutic strategies to treat diseases associated with dysregulated redox homeostasis and metabolism. Antioxid. Redox Signal. 34, 1319-1354.

Determinants of Schizophrenia Endophenotypes Based on Neuroimaging and Biochemical Parameters.

Despite extensive research, there is no convincing evidence of a reliable diagnostic biomarker for schizophrenia beyond clinical observation. Disorders of glutamatergic neurotransmission associated with N-methyl-D-aspartate (NMDA) receptor insufficiency, neuroinflammation, and redox dysregulation are the principal common mechanism linking changes in the periphery with the brain, ultimately contributing to the emergence of negative symptoms of schizophrenia that underlie differential diagnosis. The aim of the study was to evaluate the influence of these systems via peripheral and cerebral biochemical indices in relation to the patient’s clinical condition. Using neuroimaging diagnostics, we were able to define endophenotypes of schizophrenia based on objective laboratory data that form the basis of a personalized approach to diagnosis and treatment. The two distinguished endophenotypes differed in terms of the quality of life, specific schizophrenia symptoms, and glutamatergic neurotransmission metabolites in the anterior cingulate gyrus. Our results, as well as further studies of the excitatory or inhibitory balance of microcircuits, relating the redox systems on the periphery with the distant regions of the brain might allow for predicting potential biomarkers of neuropsychiatric diseases, including schizophrenia. To the best of our knowledge, our study is the first to identify an objective molecular biomarker of schizophrenia outcome.

Sodium acetate ameliorated systemic and renal oxidative stress in high-fructose insulin-resistant pregnant Wistar rats.

Pregnancy is an insulin-resistant condition especially at near term predisposing maternal kidneys to hyperinsulinemia-induced oxidative stress. The impact of fructose on renal metabolic dysregulation and oxidative stress in pregnancy requires elucidation. Short-chain fatty acids (SCFAs) are known for protective roles in oxidative stress conditions. Therefore, the study aimed at investigating fructose-induced glucose dysregulation and renal oxidative stress in pregnant and non-pregnant rats and the possible preventive role of SCFA, acetate. Thirty female Wistar rats were grouped (n = 5/group). Three groups were made pregnant (P); the other three remained non-pregnant (NP). Both pregnant and non-pregnant rats received drinking water (control), 10% fructose (w/v) (NP+F or P+F), and 10% (w/v) fructose plus sodium acetate (200 mg/kg) (NP+F+A or P+F+A) for 3 weeks. Renal and plasma glutathione antioxidant index (GSH/GSSG), G6PDH, and adenosine were significantly lower in NP+F and P+F groups compared with control while renal and plasma adenosine deaminase (ADA), xanthine oxidase (XO), uric acid (UA), lactate dehydrogenase (LDH), and malonaldehyde (MDA) were significantly elevated in NP+F and P+F groups compared with controls. HOMA-IR showed marked impairment in both NP+F and P+F groups. The P+F group revealed greater suppression in plasma and renal G6PDH-dependent antioxidant index, adenosine, and aggravation of LDH, MDA compared with the NP+F group (p < 0.05). Sodium acetate reduces plasma and renal surrogate oxidative stress markers, improved G6PD-dependent antioxidant index, and HOMA-IR in NP+F and P+F groups. Pregnancy exacerbates fructose-induced insulin resistance and renal oxidative stress whereas acetate ameliorated fructose-induced redox and glucose dysregulation in pregnant and non-pregnant rats.

Emerging Evidence Highlighting the Importance of Redox Dysregulation in the Pathogenesis of Amyotrophic Lateral Sclerosis (ALS).

The cellular redox state, or balance between cellular oxidation and reduction reactions, serves as a vital antioxidant defence system that is linked to all important cellular activities. Redox regulation is therefore a fundamental cellular process for aerobic organisms. Whilst oxidative stress is well described in neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), other aspects of redox dysfunction and their contributions to pathophysiology are only just emerging. ALS is a fatal neurodegenerative disease affecting motor neurons, with few useful treatments. Hence there is an urgent need to develop more effective therapeutics in the future. Here, we discuss the increasing evidence for redox dysregulation as an important and primary contributor to ALS pathogenesis, which is associated with multiple disease mechanisms. Understanding the connection between redox homeostasis, proteins that mediate redox regulation, and disease pathophysiology in ALS, may facilitate a better understanding of disease mechanisms, and lead to the design of better therapeutic strategies.

Distinctive Under-Expression Profile of Inflammatory and Redox Genes in the Blood of Elderly Patients with Cardiovascular Disease.

PurposeChronic low-grade inflammation and oxidative stress are present in most of the pathologic mechanisms underlying non-communicable diseases. Inflammation and redox biomarkers might therefore have a value in disease prognosis and therapy response. In this context, we performed a case–control study for assessing in whole blood the expression profile of inflammation and redox-related genes in elderly subjects with various comorbidities.Patients and MethodsIn the blood of 130 elderly subjects with various pathologies (cardiovascular disease, hypertension, dyslipidemia including hypercholesterolemia, type 2 diabetes mellitus), kept under control by polyvalent disease-specific medication, we investigated by pathway-focused qRT-PCR a panel comprising 84 inflammation-related and 84 redox-related genes.ResultsThe study highlights a distinctive expression profile of genes critically involved in NF-κB-mediated inflammation and redox signaling in the blood of patients with cardiovascular disease, characterized by significant down-regulation of the genes NFKB2, NFKBIA, RELA, RELB, AKT1, IRF1, STAT1, CD40, LTA, TRAF2, PTGS1, ALOX12, DUOX1, DUOX2, MPO, GSR, TXNRD2, HSPA1A, MSRA, and PDLIM1. This gene expression profile defines the transcriptional status of blood leukocytes in stable disease under medication control, without discriminating between disease- and therapy-related changes.ConclusionThe study brings preliminary proof on a minimally invasive strategy for monitoring disease in patients with cardiovascular pathology, from the point of view of inflammation or redox dysregulation in whole blood.

The Efficacy of Vitamin K, A Member Of Naphthoquinones in the Treatment of Cancer: A Systematic Review and Meta-Analysis.

Redox dysregulation originating from metabolic alterations in cancer cells contributes to their proliferation, invasion, and resistance to therapy. Conversely, these features represent a specific vulnerability of malignant cells that can be selectively targeted by redox chemotherapeutics. Amongst them, Vitamin K (VitK) carries the potential against cancer stem cells, in addition to the rest of tumor mass. To assess the possible benefits and safety of VitK for cancer treatment using a systematic review and meta-analysis with a mixed-methods approach. We performed a systematic search on several electronic databases for studies comparing VitK treatment with and without combination to the control groups. For quantitative studies, fully or partially reported clinical outcomes such as recurrence rates, survival, overall response and adverse reactions were assessed. For qualitative studies, a narrative synthesis was accomplished. Our analysis suggested that the clinical outcome of efficacy, the pooled hazard ratio for progression-free survival, and the pooled relative risk for overall survival, and overall response were significantly higher in the VitK therapy group compared to the placebo group (p<0.05). We did not observe any significant difference in the occurrence of adverse events between groups. Among qualitative studies, VitK treatment targeting myelodysplastic syndrome and advanced solid tumors resulted in 24.1% and 10% of clinical response, respectively. VitK not only exerts antitumor effects against a wide range of tumor types, but it also has excellent synergism with other therapeutic agents.

Activatable Nanoparticles: Recent Advances in Redox-Sensitive Magnetic Resonance Contrast Agent Candidates Capable of Detecting Inflammation.

The emergence of activatable magnetic resonance (MR) contrast agents has prompted significant interest in the detection of functional markers of diseases, resulting in the creation of a plethora of nanoprobes capable of detecting these biomarkers. These markers are commonly dysregulated in several chronic diseases, specifically select cancers and inflammatory diseases. Recently, the development of redox-sensitive nanoparticle-based contrast agents has gained momentum given advances in medicine linking several inflammatory diseases to redox imbalance. Researchers have pinpointed redox dysregulation as an opportunity to use activatable MR contrast agents to detect and stage several diseases as well as monitor the treatment of inflammatory diseases or conditions. These new classes of agents represent an advancement in the field of MR imaging as they elicit a response to stimuli, creating contrast while providing evidence of biomarker changes and commensurate disease state. Most redox-sensitive nanoparticle-based contrast agents are sensitive to reductive glutathione or oxidative reactive oxygen species. In this review, we will explore recent investigations into redox-activatable, nanoparticle-based MR contrast agent candidates.

Roles of Ion Fluxes, Metabolism, and Redox Balance in Cancer Therapy.

Recent Advances: The 2019 Nobel Prize awarded to the mechanisms for oxygen sensing and adaptation according to oxygen availability, highlighting the fundamental importance of gaseous molecules. Gaseous molecules, including reactive oxygen species (ROS), can interact with different cations generated during metabolic and redox dysregulation in cancer cells. Cross talk between calcium signaling and metabolic/redox pathways leads to network-based dyregulation in cancer. Significance: Recent discovery on using small molecules targeting the ion channels, redox signaling, and protein modification on metabolic enzymes can effectively inhibit cancer growth. Several FDA-approved drugs and clinical trials are ongoing to target the calcium channels, such as TRPV6 and TRPM8. Multiple small molecules from natural products target metablic and redox enzymes to exert an anticancer effect. Critical Issues: Small molecules targeting key ion channels, metabolic enzymes that control key aspects of metabolism, and redox proteins are promising, but their action mechanisms of the target are needed to be elucidated with advanced-omic technologies, which can give network-based and highly dimensioal data. In addition, small molecules that can directly modify the protein residues have emerged as a novel anticancer strategy. Future Directions: Advanced technology accelerates the detection of ions and metabolic and redox changes in clinical samples for diagnosis and informs the decision of cancer treatment. The improvement of ROS detection, ROS target identification, and computational-aid drug discovery also improves clincal outcome.Overall, network-based or holistic regulations of cancer via ion therapy and metabolic and redox intervention are promising as new anticancer strategies. Antioxid. Redox Signal. 34, 1108-1127.

Combatting Nitrosative Stress and Inflammation with Novel Substituted Triazinoindole Inhibitors of Aldose Reductase in PC12 Cells Exposed to 6-Hydroxydopamine Plus High Glucose.

Cellular redox dysregulation produced by aldose reductase (AR) in the presence of high blood sugar is a mechanism involved in neurodegeneration commonly observed in diabetes mellitus (DM) and Parkinson's disease (PD); therefore, AR is a key target for treatment of both diseases. The substituted triazinoindole derivatives 2-(3-thioxo-2H-[1,2,4]triazino[5,6-b]indol-5(3H)-yl) acetic acid (cemtirestat or CMTI) and 2-(3-oxo-2H-[1,2,4]triazino[5,6-b]indol-5(3H)-yl) acetic acid (COTI) are well-known AR inhibitors (ARIs). The neuroprotective properties of CMTI, COTI, the clinically used epalrestat (EPA), and the pyridoindole antioxidants stobadine and SMe1EC2 were all tested in the neurotoxic models produced by hyperglycemic glucotoxicity (HG, 75mM D-glucose, 72h), 6-hydroxydopamine (6-OHDA), and HG+6-OHDA models in PC12 cells. Cell viability decreased in all toxic models, increased by 1-5μM EPA, and decreased by COTI at ≥ 2.5μM. In the HG model alone, where compounds were present in the medium for 24h after a continuous 24-h exposure to HG, cell viability was improved by 100nM-5μM EPA, 1-10μM ARIs, and the antioxidants studied, but decreased by EPA at ≥ 10μM. In the 6-OHDA model alone, where cells were treated with compounds for 24h and further exposed to 100μM 6-OHDA (8h), only the antioxidants protected cell viability. In the HG+6-OHDA model, where cells were treated with all compounds (1nM to 50μM) for 48h and exposed to 75mM glucose for 24h followed by incubation with 6-OHDA for 8h, cell viability was protected by 100nM-10μM ARIs and 100-500nM EPA, but not by antioxidants. All ARIs inhibited the HG+6-OHDA-induced increase in iNOS, IL-1β, TNF-α, 3-NT, and total oxidant status at 1-50μM, while increased SOD, CAT, GPx, and total antioxidant status at 1-10μM. EPA and CMTI also reduced the HG+6-OHDA-induced increase in the cellular levels of nuclear factor kB (NF-KB). The neuroprotective potential of the novel ARIs and the pyridoindole antioxidants studied constitutes a promising tool for the development of therapeutic strategies against DM-induced and PD-related neurodegeneration.

Anti-Melanoma Activities of Artemisone and Prenylated Amino-Artemisinins in Combination With Known Anticancer Drugs.

The most frequently occurring cancers are those of the skin, with melanoma being the leading cause of death due to skin cancer. Breakthroughs in chemotherapy have been achieved in certain cases, though only marginal advances have been made in treatment of metastatic melanoma. Strategies aimed at inducing redox dysregulation by use of reactive oxygen species (ROS) inducers present a promising approach to cancer chemotherapy. Here we use a rational combination of an oxidant drug combined with a redox or pro-oxidant drug to optimize the cytotoxic effect. Thus we demonstrate for the first time enhanced activity of the amino-artemisinin artemisone and novel prenylated piperazine derivatives derived from dihydroartemisinin as the oxidant component, and elesclomol-Cu(II) as the redox component, against human malignant melanoma cells A375 in vitro. The combinations caused a dose dependent decrease in cell numbers and increase in apoptosis. The results indicate that oxidant-redox drug combinations have considerable potential and warrant further investigation.

In vivo 31P magnetic resonance spectroscopy study of mouse cerebral NAD content and redox state during neurodevelopment

Nicotinamide adenine dinucleotide (NAD) is an important cofactor of energy-producing pathways. The redox ratio (NAD+/NADH) reflects the cellular oxidoreductive state. Oxidative stress and redox dysregulation have been suggested to contribute to various neurological diseases. The assessment of NAD content has been recently demonstrated in large animals and human brains by 31P magnetic resonance spectroscopy. However, its measurement in small rodents has never been attempted. The purpose of this study was to investigate, in vivo, the NAD content during mouse brain neurodevelopment. 31P-MR-spectra were acquired in the mouse brain at postnatal days P20, P40, P90 and P250 at 14.1 T using a 3D-localization sequence. High spectral quality was achieved at 14.1 T. NAD+ and NADH were quantified with mean Cramér-Rao lower bound of 10% and 14%, respectively. An increase in NAD+/NADH was observed from P20 to P250 due to a decrease in [NADH]. The intracellular pH was significantly reduced with age, while the free [Mg2+] in the brain was significantly increased. This study demonstrates for the first time the feasibility of the measurement of NAD content in vivo in mouse brains during development, which opens the prospect of longitudinally studying energy metabolism and redox dysfunction in mouse models of brain pathology.

Relationship of Seminal Oxidation-Reduction Potential with Sperm DNA Integrity and pH in Idiopathic Infertile Patients

Seminal oxidative stress (OS) is one of the most promising factors to describe the causes of idiopathic male infertility. Redox balance is essential in several biological processes related to fertility, so alterations such as high reactive oxygen species (ROS) levels or low antioxidant agent levels can compromise it. MiOXSYS has been developed to evaluate the seminal static oxidation-reduction potential (sORP) and it has been proposed as an effective diagnostic biomarker. However, its relationship with parameters like sperm DNA fragmentation (SDF), chromatin compaction status or seminal pH requires further analysis, making it the object of this study. Semen and sORP analysis were performed for all samples. A terminal deoxynucleotidyl transferase dUTP nick end labeling assay (TUNEL) and Comet assay were used to assess SDF and chromomycin a3 (CMA3) test to assess sperm chromatin compaction. Regarding sORP measures, it was found that alkaline pH has an effect on sample reproducibility. To our knowledge, this unexpected effect has not been previously described. A statistical analysis showed that sORP correlated negatively with CMA3 positive cells and sperm motility, but not with SDF. As redox dysregulation, which occurs mainly at the testicular and epididymal level, causes chromatin compaction problems and leaves DNA exposed to damage, an excess of ROS could be counterbalanced further by a seminal supply of antioxidant molecules, explaining the negative correlation with CMA3 positive cells but no correlation with SDF. Our results show that the study of idiopathic infertility would benefit from a combined approach comprising OS analysis, SDF and chromatin compaction analysis.

Abstract 3572: Merlin deficiency induces redox imbalance in breast cancer

Abstract Merlin is encoded by the NF2 gene and, as a tumor suppressor, stalls cell proliferation by contact-dependent growth inhibition. Prior work from our laboratory has established that Merlin levels are significantly decreased in breast tumor tissues representing advanced grade. Moreover, Merlin expression is completely lost in cases representing metastatic breast cancer. Therefore, we mimicked Merlin deficiency by stably knocking down NF2 in non-metastatic breast cancer cells. Recognizing the role of metabolic reprogramming in tumor progression, we undertook untargeted metabolomics analysis - this effort identified low levels of reduced glutathione (GSH) in Merlin-deficient cells. Given the role of GSH as the most abundant antioxidant cofactor, we explored if a major reactive oxygen species (ROS) clearance mechanism is compromised in Merlin-deficient breast cancer cells. Indeed, accumulated levels of ROS were detected in Merlin-deficient cells, suggesting that Merlin deficiency causes redox imbalance. Quenching of elevated ROS levels attenuated migration and invasion capabilities indicating a role of ROS in intensifying malignant behaviors upon Merlin deficiency. Furthermore, dysregulated STAT3 activity upregulated the expression of NADPH oxidase (NOX) enzymes in Merlin-deficient breast cancer cells compared to their control counterparts. These findings were also recapitulated in non-tumorigenic Nf2 −/- mouse embryonic fibroblasts further supporting the key role of Merlin in these phenotypes. In conclusion, ROS accumulation and increased malignancy in Merlin-deficient cells may be the result of a dysregulated cellular redox management system. Citation Format: Mateus Mota, Brandon Metge, Lalita Shevde-Samant. Merlin deficiency induces redox imbalance in breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3572.

The Current State of the Clinical High Risk for Psychosis Research Paradigm

Psychotic disorders tend to have onset during late adolescence and early adulthood and are often chronic and debilitating. Antipsychotic drugs are not effective in treating the full array of symptoms, cognitive deficits, and functional impairments associated with these illnesses, and these drugs require maintenance dosing and carry significant side effect burdens ( 1 Steeds H. Carhart-Harris R.L. Stone J.M. Drug models of schizophrenia. Ther Adv Psychopharmacol. 2015; 5: 43-58 Crossref PubMed Scopus (80) Google Scholar ). Accordingly, many researchers are interested in developing preemptive strategies for psychotic disorders. One such approach is based on the clinical high risk for psychosis (CHR-P) paradigm, in which young people presenting with subpsychotic symptoms are followed to determine predictors of risk for conversion to frank psychosis ( 2 Yung A.R. McGorry P.D. The prodromal phase of first-episode psychosis: Past and current conceptualizations. Schizophr Bull. 1996; 22: 353-370 Crossref PubMed Scopus (871) Google Scholar ). A related goal is elucidating changes at the neural and molecular levels that participate mechanistically in the onset of full symptoms, which could facilitate the development of novel treatments targeting the contributing molecular signaling pathways. Key advantages of the CHR-P paradigm include the prospective, longitudinal nature of the research design, the focus on individuals who are at risk for psychosis during a critical period of brain and cognitive development, and the ability to differentiate biological and behavioral markers associated with illness onset from those secondary to treatments. As indicated in the articles and commentaries appearing in the current issue of Biological Psychiatry ( 3 Carpenter W.T. Classification is essential for the attenuated psychosis syndrome. Biol Psychiatry. 2020; 88: 289-290 Abstract Full Text Full Text PDF Scopus (1) Google Scholar , 4 Srihari V.H. Kane J.M. Early intervention services 2.0: Designing systems for the next generation of work. Biol Psychiatry. 2020; 88: 291-293 Abstract Full Text Full Text PDF Scopus (1) Google Scholar , 5 Gordon J.A. Heinssen R.K. Collaborative approaches to the clinical high risk state: From data to mechanism to intervention. Biol Psychiatry. 2020; 88: 287-288 Abstract Full Text Full Text PDF Scopus (3) Google Scholar , 6 Hamilton H.K. Boos A.K. Mathalon D.H. Electroencephalography and event-related potential biomarkers in individuals at clinical high risk for psychosis. Biol Psychiatry. 2020; 88: 294-303 Abstract Full Text Full Text PDF PubMed Scopus (12) Google Scholar , 7 Howes O.D. Hird E.J. Adams R.A. Corlett P.R. McGuire P. Aberrant salience, information processing, and dopaminergic signaling in people at clinical high risk for psychosis. Biol Psychiatry. 2020; 88: 304-314 Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar , 8 Mennigen E. Bearden C.E. Psychosis risk and development: What do we know from population-based studies?. Biol Psychiatry. 2020; 88: 315-325 Google Scholar , 9 Perkins D.O. Jeffries C.D. Do K.Q. Potential roles of redox dysregulation in the development of schizophrenia. Biol Psychiatry. 2020; 88: 326-336 Abstract Full Text Full Text PDF Scopus (30) Google Scholar , 10 Sanfelici R. Dwyer D.B. Antonucci L.A. Koutsouleris N. Individualized diagnostic and prognostic models for patients with psychosis risk syndromes: A meta-analytic view on the state of the art. Biol Psychiatry. 2020; 88: 349-360 Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar , 11 Taylor J.H. Calkins M.E. Gur R.E. Markers of psychosis risk in the general population. Biol Psychiatry. 2020; 88: 337-348 Google Scholar ), the field has made substantial strides using this paradigm in the past 25 years. Here, I highlight several key advances and discuss their significance in relation to the original goals of the CHR-P paradigm.

Deletion of the Mitochondrial Matrix Protein CyclophilinD Prevents Parvalbumin Interneuron Dysfunctionand Cognitive Deficits in a Mouse Model of NMDA Hypofunction.

Redox dysregulation and oxidative stress are final common pathways in the pathophysiology of a variety of psychiatric disorders, including schizophrenia. Oxidative stress causes dysfunction of GABAergic parvalbumin (PV)-positive interneurons (PVI), which are crucial for the coordination of neuronal synchrony during sensory and cognitive processing. Mitochondria are the main source of reactive oxygen species (ROS) in neurons and they control synaptic activity through their roles in energy production and intracellular calcium homeostasis. We have previously shown that in male mice transient blockade of NMDA receptors (NMDARs) during development [subcutaneous injections of 30 mg/kg ketamine (KET) on postnatal days 7, 9, and 11] results in long-lasting alterations in synaptic transmission and reduced PV expression in the adult prefrontal cortex (PFC), contributing to a behavioral phenotype that mimics multiple symptoms associated with schizophrenia. These changes correlate with oxidative stress and impaired mitochondrial function in both PVI and pyramidal cells. Here, we show that genetic deletion (Ppif-/-) of the mitochondrial matrix protein cyclophilin D (CypD) prevents perinatal KET-induced increases in ROS and the resulting deficits in PVI function, and changes in excitatory and inhibitory synaptic transmission in the PFC. Deletion of CypD also prevented KET-induced behavioral deficits in cognitive flexibility, social interaction, and novel object recognition (NOR). Taken together, these data highlight how mitochondrial activity may play an integral role in modulating PVI-mediated cognitive processes.SIGNIFICANCE STATEMENT Mitochondria are important modulators of oxidative stress and cell function, yet how mitochondrial dysfunction affects cell activity and synaptic transmission in psychiatric illnesses is not well understood. NMDA receptor (NMDAR) blockade with ketamine (KET) during development causes oxidative stress, dysfunction of parvalbumin (PV)-positive interneurons (PVI), and long-lasting physiological and behavioral changes. Here we show that mice deficient for the mitochondrial matrix protein cyclophilin D (CypD) show robust protection from PVI dysfunction following perinatal NMDAR blockade. Mitochondria serve as an essential node for a number of stress-induced signaling pathways and our experiments suggest that failure of mitochondrial redox regulation can contribute to PVI dysfunction.

Mitochondrial superoxide contributes to oxidative stress exacerbated by DNA damage response in RAD51-depleted ovarian cancer cells

Ovarian cancer is the most lethal gynecological malignancy. Abnormal homologous recombination repair, high level of reactive oxygen species (ROS) and upregulation of antioxidant genes are characteristic features of ovarian cancer. However, the molecular mechanisms governing the redox homeostasis in ovarian cancer cells remain to be fully elucidated. We here demonstrated a critical role of RAD51, a protein essential for homologous recombination, in the maintenance of redox homeostasis. We found that RAD51 is overexpressed in high grade serous ovarian cancer and is associated with poor prognosis. Depletion or inhibition of RAD51 results in G2/M arrest, increased production of reactive oxygen species and accumulation of oxidative DNA damage. Importantly, antioxidant N-acetylcysteine (NAC) significantly attenuated the induction of DNA damage and the perturbation of proliferation caused by RAD51 depletion. We further demonstrated that RAD51 inhibition or depletion led to elevated production of mitochondrial superoxide and increased accumulation of mitochondria. Moreover, CHK1 activation is required for the G2/M arrest and the generation of mitochondrial stress in response to RAD51 depletion. Together, our results indicate that nuclear DNA damage caused by RAD51 depletion may trigger mitochondria-originated redox dysregulation. Our findings suggest that a vicious cycle of nuclear DNA damage, mitochondrial accumulation and oxidative stress may contribute to the tumor-suppressive effects of RAD51 depletion or inhibition.

S69. CLINICAL HIGH RISK STATE: STRATIFICATION BASED ON CLINICAL PROFILE AND REDOX STATUS

BackgroundThe Clinical High Risk state (CHR) concept was implemented to promote the early detection of young help-seeking patients with higher risk of psychotic transition. This category is based on specific clinical criteria (EPA, 2015) and require narrow frequency/duration ratings of subclinical positive psychotic symptoms to allow its definition. Prevalence of CHR “category” appears nevertheless rare in help-seeking young people and the rate of psychotic transition of CHR state is lower than predicted by early studies. Therefore, the binary outcome of transition to psychosis proposed by the “CHR model” actually fails to be an efficient marker to stratify, in neurobiological studies, people with different psychopathological trajectories, notably those who develop psychosis from those who do not. In order to rely on a vulnerability model for schizophrenic psychosis more sensitive to psychosocial functioning and negative dimension, we study prospectively with three years of follow-up a population of help-seekers addressed for clinical suspicion of prodromal state of psychosis.We aimed here to identify subgroups of patients in a sample of subclinical psychotic states using psychological and cognitive outcomes as profiling criteria, focusing not only on transition but also on psychosocial functioning as main outcome.MethodsA total of 32 help-seeking adolescents and young adults aged 14 to 35 were referred by health care providers for a specialized evaluation in case of suspicion of a prodromal psychotic state and/or detected by the French version of the Prodromal Questionnaire (PQ-16; cut-off 6/16). Their CHR status was assessed by the Structured Interview for Psychosis-Risk Syndromes (SIPS) and the Schizophrenia Proneness Instrument, Adult (SPI-A). Individuals included in the study presented either a CHR status, a subclinical CHR status or negative symptomatology. All subjects performed an additional neuropsychological battery and blood test for redox markers (Glutathione Peroxidase (GPx) and Glutathione Reductase (GR) activities) (Xin et al, 2016). Based on their clinical profile, we made a stratification of the patients using a Principal Component Analysis.ResultsCognitive and psychological outcome stratification of all help-seekers revealed two subgroups (called group1 and group2) of patients with distinct profiles. Individuals in group1 (n=18) had greater levels of basic symptoms and general symptomatology. On the other hand, in group2 (n=14), individuals showed a weaker self-esteem and a lower rate of “living independently”. Cognitive scores for speed processing, attention, verbal learning and social cognition were significantly lower in group2 compared to group1. In addition, these cognitive outcomes were negatively correlated with negative symptoms only in group2. Analysis of redox markers revealed a positive correlation between GPx and GR activities in group1, a correlation disrupted in group2.DiscussionStratification of a cohort of young help-seekers with suspicion of prodromal psychosis, regardless of their CHR status, allowed us to distinguish two subgroups with different clinical profiles: group1 with higher levels of basic symptoms and general symptomatology, and group2 with weaker self-esteem, less autonomy and poorer neurocognition. In addition, analysis of redox markers revealed a redox dysregulation in patients with poorer cognitive profile. Considering the impact of neurocognitive impairment on functioning, special focus to patients of group2 is needed, mostly in clinical practice. Moreover, they might benefit of supplementation with antioxidant compounds such as NAC, which may improve cognitive deficits (Conus et al, 2018).

Association of MTHFR 677C > T genetic polymorphism with extrapyramidal side effects of antipsychotic treatment

Several studies have revealed a positive association between methylenetetrahydrofolate reductase (MTHFR) single nucleotide polymorphism 677C > T and schizophrenia. In T-allele carriers the functional activity of MTHFR is reduced contributing to hyperhomocysteinemia development, methionine deficiency and as a consequence - redox dysregulation and the alteration of dopamine synthesis. The aim of this study was to investigate the association of MTHFR677C > T with the severity of extrapyramidal side effects of antipsychotics in schizophrenia. The average score on the Simpson-Angus scale (SAS) in a group of patients with MTHFR 677 T-allele (n = 30; 13.27 ± 5.10, M ± SD) was statistically significantly higher (t = −2.40; p = 0.02) than in the comparison group of wild genotype MTHFR 677 CC carriers (n = 31; 9.84 ± 6.03, M ± SD), confirming the working hypothesis about a possible association of the MTHFR677 T-allele carriage with the development of extrapyramidal side effects of antipsychotics.