Protection against oxidative stress-induced neurodegeneration by a modulator for DJ-1, the wild-type of familial Parkinson's disease-linked PARK7

PARK7/DJ-1 as a Therapeutic Target in Gut-Brain Axis Diseases

It is increasingly known that Parkinson's (PD) and Alzheimer's (AD) diseases occur more frequently in patients with inflammatory gastrointestinal diseases including inflammatory bowel (IBD) or celiac disease, indicating a pathological link between them. Although epidemiological observations suggest the existence of the gut-brain axis (GBA) involving systemic inflammatory and neural pathways, little is known about the exact molecular mechanisms. Parkinson's disease 7 (PARK7/DJ-1) is a multifunctional protein whose protective role has been widely demonstrated in neurodegenerative diseases, including PD, AD, or ischemic stroke. Recent studies also revealed the importance of PARK7/DJ-1 in the maintenance of the gut microbiome and also in the regulation of intestinal inflammation. All these findings suggest that PARK7/DJ-1 may be a link and also a potential therapeutic target in gut and brain diseases. In this review, therefore, we discuss our current knowledge about PARK7/DJ-1 in the context of GBA diseases.

Moving beyond the Tip of the Iceberg: DJ-1 Implications in Cancer Metabolism

DJ-1, also called Parkinson’s protein 7 (PARK7), is ubiquitously expressed and plays multiple actions in different physiological and, especially, pathophysiological processes, as evidenced by its identification in neurodegenerative diseases and its high expression in different types of cancer. To date, the exact activity of DJ-1 in carcinogenesis has not been fully elucidated, however several recent studies disclosed its involvement in regulating fundamental pathways involved in cancer onset, development, and metastatization. At this purpose, we have dissected the role of DJ-1 in maintaining the transformed phenotype, survival, drug resistance, metastasis formation, and differentiation in cancer cells. Moreover, we have discussed the role of DJ-1 in controlling the redox status in cancer cells, along with the ability to attenuate reactive oxygen species (ROS)-dependent cell death, as well as to mediate ferropotosis. Finally, a mention to the development of therapeutic strategies targeting DJ-1 has been done. We have reported the most recent studies, aiming to shed light on the role played by DJ-1 in different cancer aspects and create the foundation for moving beyond the tip of the iceberg.

DJ-1: A promising therapeutic candidate for ischemia-reperfusion injury

DJ-1 is a multifaceted protein with pleiotropic functions that has been implicated in multiple diseases, ranging from neurodegeneration to cancer and ischemia-reperfusion injury. Ischemia is a complex pathological state arising when tissues and organs do not receive adequate levels of oxygen and nutrients. When the blood flow is restored, significant damage occurs over and above that of ischemia alone and is termed ischemia-reperfusion injury. Despite great efforts in the scientific community to ameliorate this pathology, its complex nature has rendered it challenging to obtain satisfactory treatments that translate to the clinic. In this review, we will describe the recent findings on the participation of the protein DJ-1 in the pathophysiology of ischemia-reperfusion injury, firstly introducing the features and functions of DJ-1 and, successively highlighting the therapeutic potential of the protein.

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DJ-1 has been shown to confer protection in ischemia-reperfusion injury models.

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DJ-1 protection relies on the activation of antioxidant signaling pathways.

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DJ-1 regulates mitochondrial homeostasis during ischemia and reperfusion.

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DJ-1 seems to modulate ion homeostasis during ischemia and reperfusion.

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DJ-1 may represent a promising therapeutic target for ischemia-reperfusion injury.

PARIS-DJ-1 Interaction Regulates Mitochondrial Functions in Cardiomyocytes, Which Is Critically Important in Cardiac Hypertrophy

Mitochondrial dysfunction is one of the major pathological attributes of cardiac hypertrophy and is associated with reduced expression of PGC1α in cardiomyocytes. However, the transcriptional regulation of PGC1α remains elusive. Here, we show that parkin interacting substrate (PARIS), a KRAB zinc finger protein, prevented PGC1α transcription despite the induction of cardiomyocytes with hypertrophic stimuli. Moreover, PARIS expression and its nuclear localization are enhanced in hypertrophy both in vitro and in vivo Knocking down PARIS resulted in mitochondrial biogenesis and improved respiration and other biochemical features that were compromised during hypertrophy. Furthermore, a PARIS-dependent proteome showed exclusive binding of a deSUMOylating protein called DJ-1 to PARIS in control cells, while this interaction is completely abrogated in hypertrophied cells. We further demonstrate that proteasomal degradation of DJ-1 under oxidative stress led to augmented PARIS SUMOylation and consequent repression of PGC1α promoter activity. SUMOylation-resistant mutants of PARIS failed to repress PGC1α, suggesting a critical role for PARIS SUMOylation in hypertrophy. The present study, therefore, proposes a novel regulatory pathway where DJ-1 acts as an oxidative stress sensor and contributes to the feedback loop governing PARIS-mediated mitochondrial function.

DJ-1 suppresses ferroptosis through preserving the activity of S-adenosyl homocysteine hydrolase

Ferroptosis is a newly characterized form of regulated cell death mediated by iron-dependent accumulation of lipid reactive oxygen species and holds great potential for cancer therapy. However, the molecular mechanisms underlying ferroptosis remain largely elusive. In this study, we define an integrative role of DJ-1 in ferroptosis. Inhibition of DJ-1 potently enhances the sensitivity of tumor cells to ferroptosis inducers both in vitro and in vivo. Metabolic analysis and metabolite rescue assay reveal that DJ-1 depletion inhibits the transsulfuration pathway by disrupting the formation of the S-adenosyl homocysteine hydrolase tetramer and impairing its activity. Consequently, more ferroptosis is induced when homocysteine generation is decreased, which might be the only source of glutathione biosynthesis when cystine uptake is blocked. Thus, our findings show that DJ-1 determines the response of cancer cells to ferroptosis, and highlight a candidate therapeutic target to potentially improve the effect of ferroptosis-based antitumor therapy.

DJ-1 in Parkinson's Disease: Clinical Insights and Therapeutic Perspectives

Mutations in the protein DJ-1 cause autosomal recessive forms of Parkinson’s disease (PD) and oxidized DJ-1 is found in the brains of idiopathic PD individuals. While several functions have been ascribed to DJ-1 (most notably protection from oxidative stress), its contribution to PD pathogenesis is not yet clear. Here we provide an overview of the clinical research to date on DJ-1 and the current state of knowledge regarding DJ-1 characterization in the human brain. The relevance of DJ-1 as a PD biomarker is also discussed, as are studies exploring DJ-1 as a possible therapeutic target for PD and neurodegeneration.

Astrocytic Oxidative/Nitrosative Stress Contributes to Parkinson's Disease Pathogenesis: The Dual Role of Reactive Astrocytes

Parkinson’s disease (PD) is the second most common neurodegenerative disease worldwide; it is characterized by dopaminergic neurodegeneration in the substantia nigra pars compacta, but its etiology is not fully understood. Astrocytes, a class of glial cells in the central nervous system (CNS), provide critical structural and metabolic support to neurons, but growing evidence reveals that astrocytic oxidative and nitrosative stress contributes to PD pathogenesis. As astrocytes play a critical role in the production of antioxidants and the detoxification of reactive oxygen and nitrogen species (ROS/RNS), astrocytic oxidative/nitrosative stress has emerged as a critical mediator of the etiology of PD. Cellular stress and inflammation induce reactive astrogliosis, which initiates the production of astrocytic ROS/RNS and may lead to oxidative/nitrosative stress and PD pathogenesis. Although the cause of aberrant reactive astrogliosis is unknown, gene mutations and environmental toxicants may also contribute to astrocytic oxidative/nitrosative stress. In this review, we briefly discuss the physiological functions of astrocytes and the role of astrocytic oxidative/nitrosative stress in PD pathogenesis. Additionally, we examine the impact of PD-related genes such as α-synuclein, protein deglycase DJ-1( DJ-1), Parkin, and PTEN-induced kinase 1 (PINK1) on astrocytic function, and highlight the impact of environmental toxicants, such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), rotenone, manganese, and paraquat, on astrocytic oxidative/nitrosative stress in experimental models.

Comparison of plasma PARK7 and NDKA diagnostic value in acute stroke

AIM

In this prospective case-control study we aimed to compare diagnostic value of plasma PARK7 and NDKA in early diagnosis of acute stroke and evaluate the validated diagnostic values of PARK7 and NDKA in an independent patient cohort. We then assessed the quantitative relationship between the release of these markers: stroke severity and time. Blood samples were drawn upon hospital admission and 14 days later. PARK7 and NDKA concentrations were measured using an ELISA.

RESULTS

The expression of PARK7 (area under the curve [AUC] = 0.897) in acute stroke patients was more significant than in controls, relative to the NDKA expression (AUC = 0.462); p < 0.05. Their expressions were not related to the clinical characteristics of both groups; p > 0.05.

CONCLUSION

Even though both markers cannot differentiate stroke etiologies (ischemic or hemorrhagic), plasma PARK7 has better diagnostic value than NDKA for early diagnosis of stroke. 72 plasma samples obtained from acute stroke patients and 78 plasma samples collected from non-stroke patients were analyzed in this study.

DJ-1 as a Therapeutic Target Against Cancer

DJ-1 is a gene involved in various cellular processes, including transcriptional regulation, oxidative stress response, fertilization, mitochondrial regulation, inflammatory and fibrogenic niche formation, and glycation damage prevention. Although a disease-associated genetic study within the past decade has demonstrated that the mutation of DJ-1 is associated with autosomal early-onset Parkinson's disease, increasing evidence suggests that DJ-1 also plays a critical role in tumor development and progression. In this review, we provide an overview of current knowledge concerning the role and the mechanism of DJ-1 in cancer and also discuss the possibility of DJ-1 as a therapeutic target against cancer.

Effects of a DJ-1-Binding Compound on Spatial Learning and Memory Impairment in a Mouse Model of Alzheimer's Disease

Previously, DJ-1 modulator UCP0054278/comp-B was identified by virtual screening, where comp-B interacts with DJ-1 to produce antioxidant and neuroprotective responses in Parkinson's disease models. However, the effect of comp-B in an in vivo Alzheimer's disease (AD) model is yet undetermined. Thus, we examined the effect of comp-B on spatial learning, memory, and amyloid-β (Aβ) clearance in a transgenic mouse model of AD. We found that comp-B resolved the cognitive deficits, reduced insoluble Aβ42 levels, and prevented the degeneration of synaptic functions, thereby suggesting that comp-B may become a major compound for AD treatment.

Common mechanisms of onset of cancer and neurodegenerative diseases

Onset of cancer and neurodegenerative disease occurs by abnormal cell growth and neuronal cell death, respectively, and the number of patients with both diseases has been increasing in parallel with an increase in mean lifetime, especially in developed countries. Although both diseases are sporadic, about 10% of the diseases are genetically inherited, and analyses of such familial forms of gene products have contributed to an understanding of the molecular mechanisms underlying the onset and pathogenesis of these diseases. I have been working on c-myc, a protooncogene, for a long time and identified various c-Myc-binding proteins that play roles in c-Myc-derived tumorigenesis. Among these proteins, some proteins have been found to be also responsible for the onset of neurodegenerative diseases, including Parkinson's disease, retinitis pigmentosa and cerebellar atrophy. In this review, I summarize our findings indicating the common mechanisms of onset between cancer and neurodegenerative diseases, with a focus on genes such as DJ-1 and Myc-Modulator 1 (MM-1) and signaling pathways that contribute to the onset and pathogenesis of cancer and neurodegenerative diseases.

DJ-1/PARK7, But Not Its L166P Mutant Linked to Autosomal Recessive Parkinsonism, Modulates the Transcriptional Activity of the Orphan Nuclear Receptor Nurr1 In Vitro and In Vivo

Although mutations of DJ-1 have been linked to autosomal recessive Parkinsonism for years, its physiological function and the pathological mechanism of its mutants are not well understood. We report for the first time that exogenous application of DJ-1, but not its L166P mutant, enhances the nuclear translocation and the transcriptional activity of Nurr1, a transcription factor essential for dopaminergic neuron development and maturation, both in vitro and in vivo. Knockdown of DJ-1 attenuates Nurr1 activity. Further investigation showed that signaling of Raf/MEK/ERK MAPKs is involved in this regulatory process and that activation induced by exogenous DJ-1 is antagonized by U0126, an ERK pathway inhibitor, indicating that DJ-1 modulates Nurr1 activity via the Raf/MEK/ERK pathway. Our findings shed light on the novel function of DJ-1 to enhance Nurr1 activity and provide the first insight into the molecular mechanism by which DJ-1 enhances Nurr1 activity.

Parkinson's disease proteins: Novel mitochondrial targets for cardioprotection

Ischemic heart disease (IHD) is the leading cause of death and disability worldwide. Therefore, novel therapeutic targets for protecting the heart against acute ischemia/reperfusion injury (IRI) are required to attenuate cardiomyocyte death, preserve myocardial function, and prevent the onset of heart failure. In this regard, a specific group of mitochondrial proteins, which have been linked to familial forms of Parkinson's disease (PD), may provide novel therapeutic targets for cardioprotection. In dopaminergic neurons of the substantia nigra, these PD proteins, which include Parkin, PINK1, DJ-1, LRRK2, and α-synuclein, play essential roles in preventing cell death-through maintaining normal mitochondrial function, protecting against oxidative stress, mediating mitophagy, and preventing apoptosis. These rare familial forms of PD may therefore provide important insights into the pathophysiology underlying mitochondrial dysfunction and the development of PD. Interestingly, these PD proteins are also present in the heart, but their role in myocardial health and disease is not clear. In this article, we review the role of these PD proteins in the heart and explore their potential as novel mitochondrial targets for cardioprotection.

DJ-1-dependent protective activity of DJ-1-binding compound no. 23 against neuronal cell death in MPTP-treated mouse model of Parkinson's disease

Parkinson's disease (PD) is caused by dopaminergic cell death in the substantia nigra, leading to a reduced level of dopamine in the striatum. Oxidative stress is one of the causes of PD. Since symptomatic PD therapies are used, identification of compounds or proteins that inhibit oxidative stress-induced neuronal cell death is necessary. DJ-1 is a causative gene product of familial PD and plays a role in anti-oxidative stress reaction. We have identified various DJ-1-binding compounds, including compound-23, that restored neuronal cell death and locomotion defects observed in neurotoxin-induced PD models. In this study, wild-type and DJ-1-knockout mice were injected intraperitoneally with 1 mg/kg of compound-23 and then with 30 mg/kg of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) at 1 h after injection. Five days after administration, the effects of compound-23 on MPTP-induced locomotion deficits, on dopaminergic cell death and on brain dopamine levels were analyzed by rotor rod tests, by staining cells with an anti-TH antibody and by an HPLC, respectively. The results showed that compound-23 inhibited MPTP-induced reduction of retention time on the rotor rod bar, neuronal cell death in the substantia nigra and striatum and dopamine content in wild-type mice but not in DJ-1-knockout mice, indicating a DJ-1-dependent effect of compound-23.

DJ-1 as a human oncogene and potential therapeutic target

DJ-1 is a cancer- and Parkinson's disease-associated protein that participates in different intracellular signaling pathways to protect cells from toxic stresses. DJ-1 expression, oxidation, localization, and phosphorylation are often altered in human tumors, and DJ-1 has been implicated in various aspects of transformation, including uncontrolled proliferation, invasion, metastasis, and resistance to chemotherapy and apoptosis. Despite the strong relationship between DJ-1 and cancer, which made it a particularly attractive therapeutic target for cancer treatment, the detailed mechanisms of how this oncogene coordinates altered signaling with cell survival remains elusive. In this commentary, we discuss the role of DJ-1 in transformation, highlight some of the significant aspects of and prospects for therapeutically targeting the DJ-1 signaling in cancer, and describe what the future may hold.

Baicalein prevents 6-hydroxydopamine-induced mitochondrial dysfunction in SH-SY5Y cells via inhibition of mitochondrial oxidation and up-regulation of DJ-1 protein expression

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic (DA) neurons at the substantia nigra. Mitochondrial dysfunction is involved in the mechanism of cell damage in Parkinson’s disease (PD). 6-Hydroxydopamine (6-OHDA) is a dopamine analog which specifically damages dopaminergic neurons. Baicalein has been previously reported to have potential in the treatment of PD. The purpose of the present study was to investigate the mechanism of action of baicalein against 6-OHDA injury in SH-SY5Y cells. The results showed that baicalein significantly alleviated alterations of mitochondrial redox activity and mitochondrial membrane potential induced by 6-OHDA in a dose-dependent manner in SH-SY5Y cells compared with vehicle group. Futhermore, baicalein decreased the production of ROS and upregulated the DJ-1 protein expression in SH-SY5Y cells. In addition, baicalein also inhibited ROS production and lipid peroxidation (IC₅₀ = 6.32 ± 0.03 μM) in rat brain mitochondia. In summary, the underlying mechanisms of baicalein against 6-OHDA-induced mitochondrial dysfunction may involve inhibition of mitochondrial oxidation and upregulation of DJ-1 protein expression.

Caenorhabditis elegans as an experimental tool for the study of complex neurological diseases: Parkinson's disease, Alzheimer's disease and autism spectrum disorder

The nematode Caenorhabditis elegans has a very well-defined and genetically tractable nervous system which offers an effective model to explore basic mechanistic pathways that might be underpin complex human neurological diseases. Here, the role C. elegans is playing in understanding two neurodegenerative conditions, Parkinson's and Alzheimer's disease (AD), and a complex neurological condition, autism, is used as an exemplar of the utility of this model system. C. elegans is an imperfect model of Parkinson's disease because it lacks orthologues of the human disease-related genes PARK1 and LRRK2 which are linked to the autosomal dominant form of this disease. Despite this fact, the nematode is a good model because it allows transgenic expression of these human genes and the study of the impact on dopaminergic neurons in several genetic backgrounds and environmental conditions. For AD, C. elegans has orthologues of the amyloid precursor protein and both human presenilins, PS1 and PS2. In addition, many of the neurotoxic properties linked with Aβ amyloid and tau peptides can be studied in the nematode. Autism spectrum disorder is a complex neurodevelopmental disorder characterised by impairments in human social interaction, difficulties in communication, and restrictive and repetitive behaviours. Establishing C. elegans as a model for this complex behavioural disorder is difficult; however, abnormalities in neuronal synaptic communication are implicated in the aetiology of the disorder. Numerous studies have associated autism with mutations in several genes involved in excitatory and inhibitory synapses in the mammalian brain, including neuroligin, neurexin and shank, for which there are C. elegans orthologues. Thus, several molecular pathways and behavioural phenotypes in C. elegans have been related to autism. In general, the nematode offers a series of advantages that combined with knowledge from other animal models and human research, provides a powerful complementary experimental approach for understanding the molecular mechanisms and underlying aetiology of complex neurological diseases.

Neuroprotective effect of a new DJ-1-binding compound against neurodegeneration in Parkinson's disease and stroke model rats

Background

Parkinson's disease (PD) and cerebral ischemia are chronic and acute neurodegenerative diseases, respectively, and onsets of these diseases are thought to be induced at least by oxidative stress. PD is caused by decreased dopamine levels in the substantia nigra and striatum, and cerebral ischemia occurs as a result of local reduction or arrest of blood supply. Although a precursor of dopamine and inhibitors of dopamine degradation have been used for PD therapy and an anti-oxidant have been used for cerebral ischemia therapy, cell death progresses during treatment. Reagents that prevent oxidative stress-induced cell death are therefore necessary for fundamental therapies for PD and cerebral ischemia. DJ-1, a causative gene product of a familial form of PD, PARK7, plays roles in transcriptional regulation and anti-oxidative stress, and loss of its function is thought to result in the onset of PD. Superfluous oxidation of cysteine at amino acid 106 (C106) of DJ-1 renders DJ-1 inactive, and such oxidized DJ-1 has been observed in patients with the sporadic form of PD.

Results

In this study, a compound, comp-23, that binds to DJ-1 was isolated by virtual screening. Comp-23 prevented oxidative stress-induced death of SH-SY5Y cells and primary neuronal cells of the ventral mesencephalon but not that of DJ-1-knockdown SH-SY5Y cells, indicating that the effect of the compound is specific to DJ-1. Comp-23 inhibited the production of reactive oxygen species (ROS) induced by oxidative stress and prevented excess oxidation of DJ-1. Furthermore, comp-23 prevented dopaminergic cell death in the substantia nigra and restored movement abnormality in 6-hydroxyldopamine-injected and rotenone-treated PD model rats and mice. Comp-23 also reduced infarct size of cerebral ischemia in rats that had been induced by middle cerebral artery occlusion. Protective activity of comp-23 seemed to be stronger than that of previously identified compound B.

Conclusions

The results indicate that comp-23 exerts a neuroprotective effect by reducing ROS-mediated neuronal injury, suggesting that comp-23 becomes a lead compound for PD and ischemic neurodegeneration therapies.

Proteomics analysis identifies PARK7 as an important player for renal cell resistance and survival under oxidative stress

Renal fibrosis is a process that is characterized by declining excretory renal function. The molecular mechanisms of fibrosis are not fully understood. Oxidative stress pathways were reported to be involved in renal tissue deterioration and fibrosis progression. In order to identify new molecular targets associated with oxidative stress and renal fibrosis, differential proteomics analysis was performed with established renal cell lines (TK173 and HK-2). The cells were treated with oxidative stress triggering factor H(2)O(2) and the proteome alterations were investigated. Two dimensional protein maps were generated and differentially expressed proteins were processed and identified using mass spectrometry analysis combined with data base search. Interestingly the increase of ROS in the renal cell lines upon H(2)O(2) treatment was accompanied by alteration of a large number of proteins, which could be classified in three categories: the first category grouped the proteins that have been described to be involved in fibrogenesis (e.g. ACTA2, VIN, VIM, DES, KRT, COL1A1, COL4A1), the second category, which was more interesting involved proteins of the oxidative stress pathway (PRDX1, PRDX2, PRDX6, SOD, PARK7, HYOU1), which were highly up-regulated under oxidative stress, and the third category represented proteins, which are involved in different other metabolic pathways. Among the oxidative stress proteins the up-regulation of PARK7 was accompanied by a shift in the pI as a result of oxidation. Knockdown of PARK7 using siRNA led to significant reduction in renal cell viability under oxidative stress. Under H(2)O(2) treatment the PARK7 knockdown cells showed up to 80% decrease in cell viability and an increase in apoptosis compared to the controls. These results highlight for the first time the important role of PARK7 in oxidative stress resistance in renal cells.