Induction of NQO1 and Neuroprotection by a Novel Compound KMS04014 in Parkinson’s Disease Models

Impact of NQO1 dysregulation in CNS disorders

NAD(P)H Quinone Dehydrogenase 1 (NQO1) plays a pivotal role in the regulation of neuronal function and synaptic plasticity, cellular adaptation to oxidative stress, neuroinflammatory and degenerative processes, and tumorigenesis in the central nervous system (CNS). Impairment of the NQO1 activity in the CNS can result in abnormal neurotransmitter release and clearance, increased oxidative stress, and aggravated cellular injury/death. Furthermore, it can cause disturbances in neural circuit function and synaptic neurotransmission. The abnormalities of NQO1 enzyme activity have been linked to the pathophysiological mechanisms of multiple neurological disorders, including Parkinson's disease, Alzheimer's disease, epilepsy, multiple sclerosis, cerebrovascular disease, traumatic brain injury, and brain malignancy. NQO1 contributes to various dimensions of tumorigenesis and treatment response in various brain tumors. The precise mechanisms through which abnormalities in NQO1 function contribute to these neurological disorders continue to be a subject of ongoing research. Building upon the existing knowledge, the present study reviews current investigations describing the role of NQO1 dysregulations in various neurological disorders. This study emphasizes the potential of NQO1 as a biomarker in diagnostic and prognostic approaches, as well as its suitability as a target for drug development strategies in neurological disorders.

Circulating (Poly)phenol Metabolites: Neuroprotection in a 3D Cell Model of Parkinson's Disease

SCOPE

Diets rich in (poly)phenols have been associated with positive effects on neurodegenerative disorders, such as Parkinson's disease (PD). Several low-molecular weight (poly)phenol metabolites (LMWPM) are found in the plasma after consumption of (poly)phenol-rich food. It is expected that LMWPM, upon reaching the brain, may have beneficial effects against both oxidative stress and neuroinflammation, and possibly attenuate cell death mechanisms relate to the loss of dopaminergic neurons in PD.

METHODS AND RESULTS

This study investigates the neuroprotective potential of two blood-brain barrier permeant LMWPM, catechol-O-sulfate (cat-sulf), and pyrogallol-O-sulfate (pyr-sulf), in a human 3D cell model of PD. Neurospheroids were generated from LUHMES neuronal precursor cells and challenged by 1-methyl-4-phenylpyridinium (MPP⁺ ) to induce neuronal stress. LMWPM pretreatments were differently neuroprotective towards MPP⁺ insult, presenting distinct effects on the neuronal transcriptome. Particularly, cat-sulf pretreatment appeared to boost counter-regulatory defense mechanisms (preconditioning). When MPP⁺ is applied, both LMWPM positively modulated glutathione metabolism and heat-shock response, as also favorably shifting the balance of pro/anti-apoptotic proteins.

CONCLUSIONS

Our findings point to the potential of LMWPM to trigger molecular mechanisms that help dopaminergic neurons to cope with a subsequent toxic insult. They are promising molecules to be further explored in the context of preventing and attenuating parkinsonian neurodegeneration.

ADHD-associated PARK2 copy number variants: A pilot study on gene expression and effects of supplementary deprivation in patient-derived cell lines

Recent studies show an association of Parkin RBR E3 ubiquitin protein ligase (PARK2) copy number variations (CNVs) with attention deficit hyperactivity disorder (ADHD). The aim of our pilot study to investigate gene expression associated with PARK2 CNVs in human-derived cellular models. We investigated gene expression in fibroblasts, hiPSC and dopaminergic neurons (DNs) of ADHD PARK2 deletion and duplication carriers by qRT PCR compared with healthy and ADHD cell lines without PARK2 CNVs. The selected 10 genes of interest were associated with oxidative stress response (TP53, NQO1, and NFE2L2), ubiquitin pathway (UBE3A, UBB, UBC, and ATXN3) and with a function in mitochondrial quality control (PINK1, MFN2, and ATG5). Additionally, an exploratory RNA bulk sequencing analysis in DNs was conducted. Nutrient deprivation as a supplementary deprivation stress paradigm was used to enhance potential genotype effects. At baseline, in fibroblasts, hiPSC, and DNs, there was no significant difference in gene expression after correction for multiple testing. After nutrient deprivation in fibroblasts NAD(P)H-quinone-dehydrogenase 1 (NQO1) expression was significantly increased in PARK2 CNV carriers. In a multivariate analysis, ubiquitin C (UBC) was significantly upregulated in fibroblasts of PARK2 CNV carriers. RNA sequencing analysis of DNs showed the strongest significant differential regulation in Neurontin (NNAT) at baseline and after nutrient deprivation. Our preliminary results suggest differential gene expression in pathways associated with oxidative stress, ubiquitine-proteasome, immunity, inflammation, cell growth, and differentiation, excitation/inhibition modulation, and energy metabolism in PARK2 CNV carriers compared to wildtype healthy controls and ADHD patients.

Pharmacological Modulation of Nrf2/HO-1 Signaling Pathway as a Therapeutic Target of Parkinson's Disease

Parkinson’s disease (PD) is a complex neurodegenerative disorder featuring both motor and nonmotor symptoms associated with a progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Oxidative stress (OS) has been implicated in the pathogenesis of PD. Genetic and environmental factors can produce OS, which has been implicated as a core contributor to the initiation and progression of PD through the degeneration of dopaminergic neurons. The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) orchestrates activation of multiple protective genes, including heme oxygenase-1 (HO-1), which protects cells from OS. Nrf2 has also been shown to exert anti-inflammatory effects and modulate both mitochondrial function and biogenesis. Recently, a series of studies have reported that different bioactive compounds were shown to be able to activate Nrf2/antioxidant response element (ARE) and can ameliorate PD-associated neurotoxin, both in animal models and in tissue culture. In this review, we briefly overview the sources of OS and the association between OS and the pathogenesis of PD. Then, we provided a concise overview of Nrf2/ARE pathway and delineated the role played by activation of Nrf2/HO-1 in PD. At last, we expand our discussion to the neuroprotective effects of pharmacological modulation of Nrf2/HO-1 by bioactive compounds and the potential application of Nrf2 activators for the treatment of PD. This review suggests that pharmacological modulation of Nrf2/HO-1 signaling pathway by bioactive compounds is a therapeutic target of PD.

Insulin-like growth factor II prevents oxidative and neuronal damage in cellular and mice models of Parkinson's disease

Oxidative distress and mitochondrial dysfunction, are key factors involved in the pathophysiology of Parkinson's disease (PD). The pleiotropic hormone insulin-like growth factor II (IGF-II) has shown neuroprotective and antioxidant effects in some neurodegenerative diseases. In this work, we demonstrate the protective effect of IGF-II against the damage induced by 1-methyl-4-phenylpyridinium (MPP+) in neuronal dopaminergic cell cultures and a mouse model of progressive PD. In the neuronal model, IGF-II counteracts the oxidative distress produced by MPP + protecting dopaminergic neurons. Improved mitochondrial function, increased nuclear factor (erythroid-derived 2)-like2 (NRF2) nuclear translocation along with NRF2-dependent upregulation of antioxidative enzymes, and modulation of mammalian target of rapamycin (mTOR) signalling pathway were identified as mechanisms leading to neuroprotection and the survival of dopaminergic cells. The neuroprotective effect of IGF-II against MPP + -neurotoxicity on dopaminergic neurons depends on the specific IGF-II receptor (IGF-IIr). In the mouse model, IGF-II prevents behavioural dysfunction and dopaminergic nigrostriatal pathway degeneration and mitigates neuroinflammation induced by MPP+. Our work demonstrates that hampering oxidative stress and normalising mitochondrial function through the interaction of IGF-II with its specific IGF-IIr are neuroprotective in both neuronal and mouse models. Thus, the modulation of the IGF-II/IGF-IIr signalling pathway may be a useful therapeutic approach for the prevention and treatment of PD.

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IGF-II hampers oxidative damage and promotes survival in a cellular model of PD.

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IGF-II avoids mitochondrial damage in dopaminergic cells in a model of PD.

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IGF-II receptor mediates the neuroprotective effect of IGF-II in a cellular model of PD.

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IGF-II prevents nigrostriatal degeneration and inflammation in a mice model of PD.

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IGF-II prevents behavioural dysfunction in a mice model of PD.

NQO1 mediates the anti-inflammatory effects of nootkatone in lipopolysaccharide-induced neuroinflammation by modulating the AMPK signaling pathway

Neuroinflammation and oxidative stress play key roles in the progression of neurodegenerative diseases. Thus, the use of potent anti-inflammatory/antioxidant agents has been suggested as a promising therapeutic strategy for neurodegenerative diseases. In the present study, we investigated the anti-inflammatory and antioxidant effects of nootkatone (NKT), a sesquiterpenoid compound isolated from grapefruit, in in vitro and in vivo models of neuroinflammation. In lipopolysaccharide (LPS)-stimulated BV2 microglial cells, NKT inhibited the expression of iNOS, COX-2, and pro-inflammatory cytokines, and increased the expression of the anti-inflammatory cytokine, IL-10. In addition, NKT inhibited reactive oxygen species (ROS) production and upregulated the expression of antioxidant enzymes, such as NQO1 and HO-1. Molecular mechanistic studies showed that NKT inhibited Akt, p38 MAPK, and NF-κB activities, while increasing AMPK, PKA/CREB, and Nrf2/ARE signaling in LPS-stimulated BV2 cells. Since NKT dramatically increased NQO1 expression, we investigated the role of this enzyme using pharmacological inhibition or knockdown experiments. Treatment of BV2 cells with the NQO1-specific inhibitor, dicoumarol, or with NQO1 siRNA significantly blocked NKT-mediated inhibition of NO, ROS, TNF-α, IL-1β, and upregulation of IL-10. Furthermore, NQO1 inhibition reversed the effects of NKT on pro- and anti-inflammatory signaling molecules. Intriguingly, we found that the AMPK inhibitor, compound C, mimicked the effects of dicoumarol, suggesting the presence of a crosstalk between NQO1 and AMPK. Finally, we demonstrated that NKT inhibited microglial activation, lipid peroxidation, and the expression of pro-inflammatory markers in the brains of LPS-injected mice, which was also reversed by dicoumarol. These data collectively suggest that NQO1 plays a critical role in mediating the anti-inflammatory and antioxidant effects of NKT in LPS-induced neuroinflammation by modulating AMPK and its downstream signaling pathways.

Docosahexanoic acid signals through the Nrf2-Nqo1 pathway to maintain redox balance and promote neurite outgrowth

Evidence suggests that n-3 polyunsaturated fatty acids may act as activators of the Nrf2 antioxidant pathway. The antioxidant response, in turn, promotes neuronal differentiation and neurite outgrowth. Nrf2 has recently been suggested to be a cell intrinsic mediator of docosohexanoic acid (DHA) signaling. In the current study, we assessed whether DHA-mediated axodendritic development was dependent on activation of the Nrf2 pathway and whether Nrf2 protected from agrochemical-induced neuritic retraction. Expression profiling of the DHA-enriched Fat-1 mouse brain relative to wild type showed a significant enrichment of genes associated with neuronal development and neuronal projection and genes associated with the Nrf2-transcriptional pathway. Moreover, we found that primary cortical neurons treated with DHA showed a dose-dependent increase in Nrf2 transcriptional activity and Nrf2-target gene expression. DHA-mediated activation of Nrf2 promoted neurite outgrowth and inhibited oxidative stress-induced neuritic retraction evoked by exposure to agrochemicals. Finally, we provide evidence that this effect is largely dependent on induction of the Nrf2-target gene NAD(P)H: (quinone acceptor) oxidoreductase 1 (NQO1), and that silencing of either Nrf2 or Nqo1 blocks the effects of DHA on the axodendritic compartment. Collectively, these data support a role for the Nrf2-NQO1 pathway in DHA-mediated axodendritic development and protection from agrochemical exposure.

Neuroprotective Effects of Cryptotanshinone in a Direct Reprogramming Model of Parkinson's Disease

Parkinson’s disease (PD) is a well-known age-related neurodegenerative disease. Considering the vital importance of disease modeling based on reprogramming technology, we adopted direct reprogramming to human-induced neuronal progenitor cells (hiNPCs) for in vitro assessment of potential therapeutics. In this study, we investigated the neuroprotective effects of cryptotanshinone (CTN), which has been reported to have antioxidant properties, through PD patient-derived hiNPCs (PD-iNPCs) model with induced oxidative stress and cell death by the proteasome inhibitor MG132. A cytotoxicity assay showed that CTN possesses anti-apoptotic properties in PD-hiNPCs. CTN treatment significantly reduced cellular apoptosis through mitochondrial restoration, such as the reduction in mitochondrial reactive oxygen species and increments of mitochondrial membrane potential. These effects of CTN are mediated via the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in PD-hiNPCs. Consequently, CTN could be a potential antioxidant reagent for preventing disease-related pathological phenotypes of PD.

The Nrf2-mediated defense mechanism associated with HFE genotype limits vulnerability to oxidative stress-induced toxicity

There is considerable interest in gene and environment interactions in neurodegenerative diseases. The HFE (homeostatic iron regulator) gene variant (H63D) is highly prevalent in the population and has been investigated as a disease modifier in multiple neurodegenerative diseases. We have developed a mouse model to interrogate the impact of this gene variant in a model of paraquat toxicity. Using primary astrocytes, we found that the H67D-Hfe(equivalent of the human H63D variant) astrocytes are less vulnerable than the WT-Hfe astrocytes to paraquat-induced cell death, mitochondrial damage, and cellular senescence. We hypothesized that the Hfe variant-associated protection is a result of the activation of the Nrf2 antioxidant defense system and found a significant increase in Nrf2 levels after paraquat exposure in the H67D-Hfe astrocytes than the WT-Hfe astrocytes. Moreover, decreasing Nrf2 by molecular or pharmaceutical manipulation resulted in increased vulnerability to paraquat in the H67D-Hfe astrocytes. To further elucidate the role of Hfe variant genotype in neuroprotection mediated by astrocytes, we added media from the paraquat-treated astrocytes to differentiated SH-SY5Y neuroblastoma cells and found a significantly larger reduction in the viability when treated with WT-Hfe astrocyte media than the H67D-Hfe astrocyte media possibly due to higher secretion of IL-6 observed in the WT-Hfe astrocytes. To further explore the mechanism of Nrf2 protection, we measured NQO1, the Nrf2-mediated antioxidant, in primary astrocytes and found a significantly higher NQO1 level in the H67D-Hfe astrocytes. To consider the translational potential of our findings, we utilized the PPMI (Parkinson's Progression Markers Initiative) clinical database and found that, consistent with the mouse study, H63D-HFE carriers had a significantly higher NQO1 level in the CSF than the WT-HFE carriers. Consistent with our previous reports on H63D-HFE in disease, these data further suggest that HFE genotype in the human population impacts the antioxidant defense system and can therefore alter pathogenesis.

Reasonably activating Nrf2: A long-term, effective and controllable strategy for neurodegenerative diseases

Neurodegenerative diseases are a variety of debilitating and fatal disorder in central nervous system (CNS). Besides targeting neuronal activity by influencing neurotransmitters or their corresponding receptors, modulating the underlying processes that lead to cell death, such as oxidative stress and mitochondrial dysfunction, should also be emphasized as an assistant strategy for neurodegeneration therapy. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) has been closely verified to be related to anti-inflammation and oxidative stress, rationally regulating its belonging pathway and activating Nrf2 is emphasized to be a potential treatment approach. There have existed multiple Nrf2 activators with different mechanisms and diverse structures, but those applied for neuro-disorders are still limited. On the basis of research arrangement and compound summary, we put forward the limitations of existing Nrf2 activators for neurodegenerative diseases and their future developing directions in enhancing the blood-brain barrier permeability to make Nrf2 activators function in CNS and designing Nrf2-based multi-target-directed ligands to affect multiple nodes in pathology of neurodegenerative diseases.

Protective effects of DA-9805 on dopaminergic neurons against 6-hydroxydopamine-induced neurotoxicity in the models of Parkinson's disease

With the elderly population rapidly growing, the prevalence of Parkinson's disease (PD) is quickly increasing because neurodegenerative disorders are usually late-onset. Herbal medicines and formula are adjuvant therapies of conventional PD agents, which result in serious side effects with long-term use. This study evaluated the neuroprotective effects of DA-9805, a standardized herbal formula that consists of an ethanolic extract of Moutan Cortex Radix, Angelica Dahuricae Radix, and Bupleuri Radix against 6-hydroxydopamine (6-OHDA)-induced cytotoxicity in vitro and in vivo. In PC12 cells, DA-9805 at concentrations of 1 and 10 μg/mL ameliorated cell viability, which was reduced by 6-OHDA. In addition, DA-9805 activated the extracellular-regulated kinase-nuclear transcription factor-erythroid 2-related factor 2 pathway, subsequently stimulating antioxidative enzymes such as NAD(P)H:quinone oxidoreductase 1 and catalase and suppressing apoptosis. Furthermore, DA-9805 prevented 6-OHDA-induced movement impairment, as well as a decrease of dopaminergic neurons and dopamine transmission in rodents. Taken together, these results suggest that the mixed herbal formula DA-9805 may be a pharmaceutical agent for preventing or improving PD.

NQO1: A target for the treatment of cancer and neurological diseases, and a model to understand loss of function disease mechanisms

NAD(P)H quinone oxidoreductase 1 (NQO1) is a multi-functional protein that catalyses the reduction of quinones (and other molecules), thus playing roles in xenobiotic detoxification and redox balance, and also has roles in stabilising apoptosis regulators such as p53. The structure and enzymology of NQO1 is well-characterised, showing a substituted enzyme mechanism in which NAD(P)H binds first and reduces an FAD cofactor in the active site, assisted by a charge relay system involving Tyr-155 and His-161. Protein dynamics play important role in physio-pathological aspects of this protein. NQO1 is a good target to treat cancer due to its overexpression in cancer cells. A polymorphic form of NQO1 (p.P187S) is associated with increased cancer risk and certain neurological disorders (such as multiple sclerosis and Alzheimer´s disease), possibly due to its roles in the antioxidant defence. p.P187S has greatly reduced FAD affinity and stability, due to destabilization of the flavin binding site and the C-terminal domain, which leading to reduced activity and enhanced degradation. Suppressor mutations partially restore the activity of p.P187S by local stabilization of these regions, and showing long-range allosteric communication within the protein. Consequently, the correction of NQO1 misfolding by pharmacological chaperones is a viable strategy, which may be useful to treat cancer and some neurological conditions, targeting structural spots linked to specific disease-mechanisms. Thus, NQO1 emerges as a good model to investigate loss of function mechanisms in genetic diseases as well as to improve strategies to discriminate between neutral and pathogenic variants in genome-wide sequencing studies.

Hydralazine Protects Nigrostriatal Dopaminergic Neurons From MPP+ and MPTP Induced Neurotoxicity: Roles of Nrf2-ARE Signaling Pathway

Although the pathogenic mechanisms of Parkinson's disease (PD) remain unclear, ample empirical evidence suggests that oxidative stress is involved in the pathogenesis of this disease. The nuclear factor E2-related factor 2 (Nrf2) is known to activate several antioxidant response element (ARE)-driven antioxidative genes that prevents oxidative stress in vitro and in vivo. Moreover, it was documented that hydralazine is a potent Nrf2 activator. In this study, we tested whether hydralazine can attenuate 1-Methyl-4-phenylpyridinium (MPP⁺) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)- induced neurotoxicity in vitro and in vivo by activating Nrf2 and its downstream network of antioxidative genes. We found that treatment with hydralazine attenuated MPP⁺ or H₂O₂-induced loss of cell viability in human neuroblastoma cell line (SH-SY5Y). In addition, hydralazine significantly promoted the nuclear translocation of Nrf2, and upregulated the expression of its downstream antioxidative genes. Further, knockout of Nrf2 abolished the protection conferred by hydralazine on MPP⁺ -induced cell death. Similar findings were observed in vivo. Before, during, and after MPTP 30 mg/kg (i.p.) administration for 7 days, the mice were given hydralazine (Hyd) 51.7 mg/kg per day by oral gavage for 3 weeks. Oral administration of hydralazine ameliorated oxidative stress, MPTP-induced behavioral disorder, and loss of neurons of dopaminergic system in the substantia nigra (SN) and striatum, all of which were attributed to its ability to activate the Nrf2-ARE pathway. Hydralazine increased the migration of Nrf2 to the nucleus in dopaminergic neurons, enhanced the expression of its downstream antioxidative genes. Together, these datasets show that the Nrf2-ARE pathway mediates the protective effects of hydralazine on Parkinson's disease.

Transcriptomic signatures of schizophrenia revealed by dopamine perturbation in an ex vivo model

The dopaminergic hypothesis of schizophrenia (SZ) postulates that dopaminergic over activity causes psychosis, a central feature of SZ, based on the observation that blocking dopamine (DA) improves psychotic symptoms. DA is known to have both receptor- and non-receptor-mediated effects, including oxidative mechanisms that lead to apoptosis. The role of DA-mediated oxidative processes in SZ has been little studied. Here, we have used a cell perturbation approach and measured transcriptomic profiles by RNAseq to study the effect of DA exposure on transcription in B-cell transformed lymphoblastoid cell lines (LCLs) from 514 SZ cases and 690 controls. We found that DA had widespread effects on both cell growth and gene expression in LCLs. Overall, 1455 genes showed statistically significant differential DA response in SZ cases and controls. This set of differentially expressed genes is enriched for brain expression and for functions related to immune processes and apoptosis, suggesting that DA may play a role in SZ pathogenesis through modulating those systems. Moreover, we observed a non-significant enrichment of genes near genome-wide significant SZ loci and with genes spanned by SZ-associated copy number variants (CNVs), which suggests convergent pathogenic mechanisms detected by both genetic association and gene expression. The study suggests a novel role of DA in the biological processes of immune and apoptosis that may be relevant to SZ pathogenesis. Furthermore, our results show the utility of pathophysiologically relevant perturbation experiments to investigate the biology of complex mental disorders.

Overexpression of CYB5R3 and NQO1, two NAD+ -producing enzymes, mimics aspects of caloric restriction

Calorie restriction (CR) is one of the most robust means to improve health and survival in model organisms. CR imposes a metabolic program that leads to increased stress resistance and delayed onset of chronic diseases, including cancer. In rodents, CR induces the upregulation of two NADH-dehydrogenases, namely NAD(P)H:quinone oxidoreductase 1 (Nqo1) and cytochrome b5 reductase 3 (Cyb5r3), which provide electrons for energy metabolism. It has been proposed that this upregulation may be responsible for some of the beneficial effects of CR, and defects in their activity are linked to aging and several age-associated diseases. However, it is unclear whether changes in metabolic homeostasis solely through upregulation of these NADH-dehydrogenases have a positive impact on health and survival. We generated a mouse that overexpresses both metabolic enzymes leading to phenotypes that resemble aspects of CR including a modest increase in lifespan, greater physical performance, a decrease in chronic inflammation, and, importantly, protection against carcinogenesis, one of the main hallmarks of CR. Furthermore, these animals showed an enhancement of metabolic flexibility and a significant upregulation of the NAD+ /sirtuin pathway. The results highlight the importance of these NAD+ producers for the promotion of health and extended lifespan.

Potential repositioning of exemestane as a neuroprotective agent for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder characterised by selective degeneration of the nigral dopaminergic neurons, and neuroinflammation and oxidative stress are believed to be involved in its pathogenesis. In the present study, we provide data that the synthetic steroid exemestane, which is currently being used to treat breast cancer, may be useful for PD therapy. In BV-2 microglial cells, exemestane activated the transcription factor Nrf2 and induced expression of the Nrf2-dependent genes that encode the antioxidant enzymes NAD(P)H: quinone oxidoreductase 1, haem oxygenase-1, and glutamylcysteine ligase. It also downregulated gene expression of inducible nitric oxide (NO) synthase, lowered the levels of NO and reactive oxygen species, interleukin-1β and tumour necrosis factor-α in lipopolysaccharide-activated microglial cells. In CATH.a dopaminergic neuronal cells, exemestane also induced the same set of Nrf2-dependent antioxidant enzyme genes and provided neuroprotection against oxidative damage. In vivo, the drug protected the nigral dopaminergic neurons, decreased microglial activation, and prevented motor deficits in C57Bl/6 male mice that had been administered with the dopaminergic neurotoxin MPTP. Taken together, the results suggested a utility of repositioning exemestane towards disease-modifying therapy for PD.

Identification of NQO1 and ferrochelatase as interaction partners for neuroprotective N-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-arylamides

Affinity chromatography was used to identify potential cellular targets that are responsible for neuroprotective activity of N-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-arylamides. Active and inactive representatives of N-{[2-(4-phenyl-piperazin-1-yl)-ethyl]-phenyl}-arylamides bearing an extended linker were synthesized and immobilized on an agarose-based matrix. This was followed by the identification of specifically bound proteins isolated out of the whole rat brain extract. Inducible flavoprotein NAD(P)H:quinone oxidoreductase (NQO1) was identified as candidates for cellular targets.

Activation of the Nrf2 signaling pathway and neuroprotection of nigral dopaminergic neurons by a novel synthetic compound KMS99220

The transcription factor Nrf2 is known to induce gene expression of antioxidant enzymes and proteasome subunits. Because both oxidative stress and protein aggregation have damaging effects on neurons, activation of the Nrf2 signaling should be beneficial against neurodegeneration. In this study, we report a novel synthetic morpholine-containing chalcone KMS99220 that confers neuroprotection. It showed high binding affinity to the Nrf2 inhibitory protein Keap-1 and increased nuclear translocation of Nrf2 and gene expression of the antioxidant enzymes heme oxygenase-1, NAD(P)H:quinone oxidoreductase-1, and the catalytic and modifier subunits of glutamate-cysteine ligase in dopaminergic CATH.a cells. KMS99220 also increased expression of the proteasome subunits PSMB5, PSMB7, PSMB8 and PSMA1, and the respective chymotrypsin and trypsin-like proteasomal enzyme activities, and reduced α-synuclein aggregate in GFP-α-syn A53T-overexpressing cells. KMS99220 exhibited a favorable pharmacokinetic profile with excellent bioavailability and metabolic stability, did not interfere with activities of the cytochrome p450 isotypes, and showed no apparent in vivo toxicity when administered up to 2000 mg/kg. In 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated mice, oral administration of KMS99220 prevented degeneration of the nigral dopaminergic neurons, induced the Nrf2 target genes, and effectively prevented the associated motor deficits. These results suggest KMS99220 as a potential candidate for therapy against Parkinson's disease.

Lowering the concentration affects the migration and viability of intracerebroventricular-delivered human mesenchymal stem cells

Due to their widely known therapeutic benefits, mesenchymal stem cells have been proposed as a novel treatment option for a wide range of diseases including Alzheimer's disease. To maximize these benefits, critical factors such as delivery route, cell viability, and cell migration must be accounted for. Out of the various delivery routes to the brain, the intracerebroventricular (ICV) route stands out due to the widespread distribution that can occur via cerebrospinal fluid flow. The major objective of this present study was to observe how altering cell concentration influences the migration and viability of human umbilical cord blood derived-mesenchymal stem cells (hUCB-MSCs), delivered via ICV injection, in the brains of wild-type (WT) mice. C3H/C57 WT mice were divided into three groups and were injected with 1 × 10⁵ hUCB-MSCs suspended in varying volumes: high (3 μl), middle (5 μl), and low (7 μl) concentrations, respectively. Lowering the concentration increased the migratory capabilities and elevated the viability of hUCB-MSCs. These results suggest that cell concentration can affect the physiological state of hUCB-MSCs, and thus the extent of therapeutic efficacy that can be achieved.

IGF-II promotes neuroprotection and neuroplasticity recovery in a long-lasting model of oxidative damage induced by glucocorticoids

Insulin-like growth factor-II (IGF-II) is a naturally occurring hormone that exerts neurotrophic and neuroprotective properties in a wide range of neurodegenerative diseases and ageing. Accumulating evidence suggests that the effects of IGF-II in the brain may be explained by its binding to the specific transmembrane receptor, IGFII/M6P receptor (IGF-IIR). However, relatively little is known regarding the role of IGF-II through IGF-IIR in neuroprotection. Here, using adult cortical neuronal cultures, we investigated whether IGF-II exhibits long-term antioxidant effects and neuroprotection at the synaptic level after oxidative damage induced by high and transient levels of corticosterone (CORT). Furthermore, the involvement of the IGF-IIR was also studied to elucidate its role in the neuroprotective actions of IGF-II. We found that neurons treated with IGF-II after CORT incubation showed reduced oxidative stress damage and recovered antioxidant status (normalized total antioxidant status, lipid hydroperoxides and NAD(P) H:quinone oxidoreductase activity). Similar results were obtained when mitochondria function was analysed (cytochrome c oxidase activity, mitochondrial membrane potential and subcellular mitochondrial distribution). Furthermore, neuronal impairment and degeneration were also assessed (synaptophysin and PSD-95 expression, presynaptic function and FluoroJade B® stain). IGF-II was also able to recover the long-lasting neuronal cell damage. Finally, the effects of IGF-II were not blocked by an IGF-IR antagonist, suggesting the involvement of IGF-IIR. Altogether these results suggest that, in or model, IGF-II through IGF-IIR is able to revert the oxidative damage induced by CORT. In accordance with the neuroprotective role of the IGF-II/IGF-IIR reported in our study, pharmacotherapy approaches targeting this pathway may be useful for the treatment of diseases associated with cognitive deficits (i.e., neurodegenerative disorders, depression, etc.).

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First evidence that IGF-II reverts oxidative synaptic damage produced by corticoids.

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IGF-II recovers mitochondrial function in synapses after oxidative damage.

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IGF-II restores mitochondrial distribution in neurons after oxidative damage.

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Evidence of the involvement of IGF-II receptor in the recovery of synaptic function.

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IGF-II reverts neurodegeneration induced by oxidative damage produced by corticoids.

Nrf2--a therapeutic target for the treatment of neurodegenerative diseases

The brain is very sensitive to changes in redox status; thus maintaining redox homeostasis in the brain is critical for the prevention of accumulating oxidative damage. Aging is the primary risk factor for developing neurodegenerative diseases. In addition to age, genetic and environmental risk factors have also been associated with disease development. The primary reactive insults associated with the aging process are a result of oxidative stress (OS) and nitrosative stress (NS). Markers of increased oxidative stress, protein and DNA modification, inflammation, and dysfunctional proteostasis have all been implicated in contributing to the progression of neurodegeneration. The ability of the cell to combat OS/NS and maintain a clearance mechanism for misfolded aggregating proteins determines whether or not it will survive. A critical pathway in this regard is the Nrf2 (nuclear factor erythroid 2-related factor 2)- antioxidant response element (ARE) pathway. Nrf2 activation has been shown to mitigate a number of pathologic mechanisms associated with Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease, and multiple sclerosis. This review will focus on the role of Nrf2 in these diseases and the potential for Nrf2 activation to attenuate disease progression.