4-Aminopyridine Protects Nigral Dopaminergic Neurons in the MPTP Mouse Model of Parkinson's Disease.

Various pharmacological blockers targeting K+ channel have been identified to be related to the treatment of Parkinson's disease (PD). Previous studies showed that 4-Aminopyridine (4-AP), a wide-spectrum K+ channel blocker, was able to attenuate apomorphine-induced rotation in parkinsonism rats, indicating the possible beneficial effects in attenuation of PD motor symptoms. However, it is unclear whether 4-AP exhibits neuroprotective effects against the neurodegeneration of substantia nigra (SN)-striatum system in PD. In this study, the 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse model was employed to evaluate the neuroprotective effects of 4-AP. Results showed that 4-AP inhibited MPTP-induced dopaminergic neuronal loss in the SN as well as dopamine depletion in the striatum. Behavior indexes of open field test and rotarod test confirmed that 4-AP attenuated MPTP-induced motor deficits. We also showed that 4-AP treatment could significantly attenuate the MPTP-induced increase in malonaldehyde (MDA) levels and decrease in superoxide dismutase (SOD) levels. Additionally, MPTP significantly reduced the Bcl-2 expression and promoted the Caspase-3 activation; 4-AP protected dopaminergic neurons against MPTP-induced neurotoxicity by reversing these changes. These results indicate that 4-AP exerts a neuroprotective effect on dopaminergic neurons against MPTP by decreasing oxidative stress and apoptosis. This provides a promising therapeutic target for the treatment of PD.

Exercise attenuates mitochondrial autophagy and neuronal degeneration in MPTP induced Parkinson's disease by regulating inflammatory pathway.

Parkinson's disease (PD) is a chronic neuronal loss of dopamine and drugs used for its management has several limitations. The present report determines the effect of exercise on mitochondrial autophagy against PD. Parkinson's disease was induced by 15 doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP; 30 mg/kg, i.p.) for 3 weeks, on five consecutive days in a week. Exposure of exercise was provided for 40 min for a period of 2 weeks after PD confirmation. Assessment of behaviour was performed to evaluate the effect of exercise on motor function and cognitive function in PD rats. Levels of reactive oxygen species (ROS) and inflammatory cytokines were assessed in PD rats using enzyme linked immunosorbent assay (ELISA). Expression of myocyte-specific enhancer factor 2D (MEF2D) and NADH dehydrogenase 6 (ND6) was estimated in PD rats. Exposure to exercise ameliorates the altered motor function and cognitive function in PD rats. There was a reduction in ROS and cytokine levels in the brain tissue of the exercise group compared to the negative control group. Exercise ameliorates the altered expression of apoptotic proteins and mRNA expression of MEF2D and ND6 in the brain tissue of MPTP induced PD rats. In conclusion, data of study reveal that exercise protects the mitochondrial autophagy in PD rats by reducing inflammatory cytokines and oxidative stress.

Polygonatum sibiricum Polysaccharides Protect against MPP-Induced Neurotoxicity via the Akt/mTOR and Nrf2 Pathways.

Polygonatum sibiricum, a well-known life-prolonging tonic in Chinese medicine, has been widely used for nourishing nerves in the orient, but the underlying molecular mechanisms remain unclear. In this study, we found that P. sibiricum polysaccharides (PSP) ameliorated 1-methyl-4-phenyl-1,2.3,6-tetrahydropyridine- (MPTP-) induced locomotor activity deficiency and dopaminergic neuronal loss in an in vivo Parkinson's disease (PD) mouse model. Additionally, PSP pretreatment inhibited N-methyl-4-phenylpyridine (MPP+) induced the production of reactive oxygen species, increasing the ratio of reduced glutathione/oxidized glutathione. In vitro experiments showed that PSP promoted the proliferation of N2a cells in a dose-dependent manner, while exhibiting effects against oxidative stress and neuronal apoptosis elicited by MPP+. These effects were found to be associated with the activation of Akt/mTOR-mediated p70S6K and 4E-BP1 signaling pathways, as well as nuclear factor erythroid 2-related factor 2- (Nrf2-) mediated NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase-1 (HO-1), glutamate-cysteine ligase catalytic subunit (Gclc), and glutamate-cysteine ligase modulatory subunit (Gclm), resulting in antiapoptotic and antioxidative effects. Meanwhile, PSP exhibited no chronic toxicity in C57BJ/6 mice. Together, our results suggest that PSP can serve as a promising therapeutic candidate with neuroprotective properties in preventing PD.

Protection by rhynchophylline against MPTP/MPP+-induced neurotoxicity via regulating PI3K/Akt pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Isolated from Uncaria rhynchophylla (U. rhynchophylla), rhynchophylline (Rhy) has been applied for treating diseases related to central nervous system such as Parkinson's disease. Nevertheless, the molecular mechanism of the neuroprotective effect has not been well interpreted. AIM OF THE STUDY: To investigate the effects of Rhy on MPTP/MPP + -induced neurotoxicity in C57BL/6 mice or PC12 cells and study the mechanisms involved. MATERIALS AND METHODS: The neuroprotective effect of Rhy on MPTP-induced neurotoxicity was evaluated by spontaneous motor activity test, as well as a test of rota-rod on a rat model of Parkinson's disease. The numbers of TH-positive neurons in the substantia nigra pars compacta (SNpc) was assessed by immunohistological. CCK-8, lactate dehydrogenase (LDH), reactive oxygen species (ROS), the concentration of intracellular calcium ([Ca2+]i) and flow cytometry analysis were performed to evaluate the pharmacological property of Rhy on 1-methyl-4-phenylpyridinium (MPP+) induced neurotoxicity in PC12 cells. Besides, LY294002, a PI3K inhibitor was employed to determine the underlying molecular signaling pathway revealing the effect of Rhy by western-blot analysis. RESULTS: The results showed that Rhy exhibited a protective effect against the MPTP-induced decrease in tyrosine hydroxylase (TH)-positive fibers in the substantia nigra at 30 mg/kg, demonstrated by the immunohistological and behavioral outcomes. Furthermore, it has been indicated that cell viability was improved and the MPP+-induced apoptosis was inhibited after the treatment of Rhy at 20 µM, which were severally analyzed by the CCK-8 and the Annexin V/propidium iodide staining method. In addition, Rhy treatment attenuated MPP+-induced up-regulation of LDH, ([Ca2+]i), and the levels of ROS. Besides, it can be revealed from the Western blot assay that LY294002, as a selective Phosphatidylinositol 3-Kinase (PI3K) inhibitor, effectively inhibited the Akt phosphorylation caused by Rhy, which suggested that Rhy showed its protective property through the activated the PI3K/Akt signaling pathway. Moreover, the Rhy-induced decreases of Bax and caspase-3 as the proapoptotic markers and the increase of Bcl-2 as the antiapoptotic marker, were blocked by LY294002 in the MPP+-treated PC12 cells. CONCLUSIONS: Rhy exerts a neuroprotective effect is partly mediated by activating the PI3K/Akt signaling pathway.

Synergistic effect of electric stimulation and mesenchymal stem cells against Parkinson's disease.

Electroconvulsive therapy (ECT) has known beneficial effects on the core motor symptoms of Parkinson's disease (PD), likely through induction of dopamine release and sensitivity of dopamine receptors. Mesenchymal stem cells (MSCs) can salvage loss of dopamine in PD through their differentiation into dopaminergic neurons. However, it is not known if combined ECT and MSC transplantation may have a synergistic effect against PD. Here, we showed that ECT significantly increased the differentiation of the transplanted MSCs into dopaminergic neurons in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. On the other hand, transplantation of MSCs significantly increased dopamine levels after ECT. Co-application of ECT and MSC transplantation generated a synergistic effect through increases in dopamine and decreases in pro-inflammatory cytokines, resulting in significantly attenuated defect in stepping test and rotational behavior in MPTP-mice. Together, our data suggest that combined ECT and MSC transplantation can be a valuable treatment of PD.

Neuroprotective Activities of Long-Acting Granulocyte-Macrophage Colony-Stimulating Factor (mPDM608) in 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Intoxicated Mice.

Loss of dopaminergic neurons along the nigrostriatal axis, neuroinflammation, and peripheral immune dysfunction are the pathobiological hallmarks of Parkinson's disease (PD). Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been successfully tested for PD treatment. GM-CSF is a known immune modulator that induces regulatory T cells (Tregs) and serves as a neuronal protectant in a broad range of neurodegenerative diseases. Due to its short half-life, limited biodistribution, and potential adverse effects, alternative long-acting treatment schemes are of immediate need. A long-acting mouse GM-CSF (mPDM608) was developed through Calibr, a Division of Scripps Research. Following mPDM608 treatment, complete hematologic and chemistry profiles and T-cell phenotypes and functions were determined. Neuroprotective and anti-inflammatory capacities of mPDM608 were assessed in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated mice that included transcriptomic immune profiles. Treatment with a single dose of mPDM608 resulted in dose-dependent spleen and white blood cell increases with parallel enhancements in Treg numbers and immunosuppressive function. A shift in CD4+ T-cell gene expression towards an anti-inflammatory phenotype corresponded with decreased microgliosis and increased dopaminergic neuronal cell survival. mPDM608 elicited a neuroprotective peripheral immune transformation. The observed phenotypic shift and neuroprotective response was greater than observed with recombinant GM-CSF (rGM-CSF) suggesting human PDM608 as a candidate for PD treatment.

LncRNA H19 Attenuates Apoptosis in MPTP-Induced Parkinson's Disease Through Regulating miR-585-3p/PIK3R3.

Parkinson's disease (PD) is a prevalent age-related neurodegenerative disease which is modulated by various molecules, including long non-coding RNAs (lncRNAs). LncRNA H19 has been shown to be associated with PD progression, but the mechanism is still unclear. This research aims to investigate the role of H19 in PD development and the detailed mechanisms. Our results showed that H19 was down-regulated in brain tissue of MPTP-induced PD mice (in vivo) and in MPP+ treated human neuroblastoma cells. miR-585-3p was verified to be a target of lncRNA H19 and was negatively regulated by H19. In addition, H19 could increase the expression of PIK3R3 through miR-585-3p. In vitro results indicated that H19 inhibited the apoptosis of MPP+ treated neuroblastoma cells by regulating of miR-585-3p. Moreover, in PD model mice, overexpression of H19 attenuated MPTP-induced neuronal apoptosis. In summary, our present research demonstrated that LncRNA H19 could attenuate neurons apoptosis in MPTP-induced PD mice as well as MPP+ treated neuroblastoma cells through regulating miR-585-3p/PIK3R3. The results may provide a potential theoretical experimental data for the clinical treatment of PD through targeting lncRNAs or miRNAs.

Chrysin restores MPTP induced neuroinflammation, oxidative stress and neurotrophic factors in an acute Parkinson's disease mouse model.

Parkinson disease occurs due to the depletion of dopaminergic neurons in brain resulting in decreased dopamine level and abnormal protein aggregation. Chrysin is a flavonoid which possesses pharmacological properties against various diseases like hypertension, diabetes, cancer, etc. According to the recent literatures, it is evidenced that chrysin protects mice against Focal Cerebral Ischemia/Reperfusion Injury. The present study aimed to elucidate the effect of chrysin on neuronal restoration in MPTP intoxicated acute mice model. From the results, it is revealed that the pre-treatment with chrysin protected MPTP induced degeneration of nigra-striatal neurons. It is observed that chrysin also ameliorates MPTP induced oxidative stress in mice by upregulating GSH, SOD and downregulating LPO levels. The motor dysfunction is also found to be enhanced which was evidenced through Beam walk, Horizontal grid and vertical grid tests. Pre-treatment with chrysin also averted MPTP induced alterations in neurotrophic factors, inflammatory markers and Dopamine contents. The findings of the present study clearly indicated that the chrysin reversed the neurochemical deficits, oxidative stress and behavioral abnormalities in PD mice and offers promising strategy for the treatment of neurodegenerative diseases.

MicroRNA-190 alleviates neuronal damage and inhibits neuroinflammation via Nlrp3 in MPTP-induced Parkinson's disease mouse model.

Parkinson's disease (PD) is neurodegenerative dyskinesia characterized by loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Although neuroinflammation is one of the pathological features of PD, its mechanism of promoting PD is still not fully understood. Recently, the microRNA (miR) is considered to play a critical regulatory role in inflammatory responses. In this study, we examined the anti-inflammatory activity, antineuronal injury, and the underlying target of miR-190 with MPTP-induced PD mouse model and BV2 cells. The results showed that miR-190 is downregulated in lipopolysaccharide (LPS)-induced BV2 cells; however, when the miR-190 overexpressed, the expression of proinflammatory mediators, such as iNOS, IL-6, TNF-α, and TGF-ß1, were inhibited and the anti-inflammatory mediator such IL-10 was increased. In addition, we predicted the potential target of miR-190 to be Nlrp3 and verified by luciferase reporter assay. The results also showed that Nlrp3 was upregulated in LPS-induced BV2 cells, whereas knockdown of Nlrp3 inhibited the LPS-induced inflammatory response in BV2 cells. Furthermore, upregulation of miR-190 or knockdown of Nlrp3 inhibited LPS-induced apoptosis in BV2 cells. However, the apoptosis inhibition effect of miR-190 was abrogated by overexpression of Nlrp3. Finally, upregulation of miR-190 inhibited the activation of microglial cells and inflammation and attenuated the tyrosine hydroxylase loss in SNpc in MPTP-induced PD mice. In conclusion, we demonstrated that miR-190 alleviates neuronal damage and inhibits inflammation via negatively regulating the expression and activation of Nlrp3 in MPTP-induced PD mouse model.

Nicotine improved the olfactory impairment in MPTP-induced mouse model of Parkinson's disease.

Olfactory impairment is an early feature of patients with Parkinson's disease (PD). Retrospective epidemiological studies reported lower scores on the University of Pennsylvania Smell Identification Test (UPSIT) in non-smokers than smokers with PD and showed an inverse correlation between susceptibility to PD and a person's history of smoking. But the mechanisms by which cigarettes affect olfaction in PD are not fully understood. So we investigated the effect of nicotine on the olfactory function in 1-methyl-4-phenyl-1, 2, 3, 6 tetrahydropyridine (MPTP)-treated mice. We observed that nicotine improved locomotor activity and protection against dopaminergic neuron loss in the midbrain in MPTP-treated mice. Compared to controls, MPTP-treated mice showed a deficit of odor discrimination and odor detection, which were alleviated by nicotine treatment. But no significant changes were found in olfactory memory in MPTP-treated mice. Moreover, we detected a marked decrease of Choline acetyltransferase (ChAT) expression in the olfactory bulb (OB) in MPTP-treated mice, which was also attenuated by nicotine administration. In addition, nicotine ameliorated the loss of cholinergic neurons and dopaminergic innervation in the horizontal limb of the diagonal band (HDB), which is the primary origin of cholinergic input to the OB. Our results suggested that nicotine could improve the olfactory impairment by protecting cholinergic systems in the OB of MPTP-treated mice. And nicotine protection of cholinergic systems in the OB is relevant to attenuating dopaminergic neuron loss in the midbrain and HDB.

A simple method to study motor and non-motor behaviors in adult zebrafish.

BACKGROUND: Motor and non-motor behavior analyses are increasingly utilizied in drug discovery and screening, detection of neurobehavioral disorders and chemical toxicology. The emergence of computational approaches has helped to develop different tools to analyse complex behaviors. Analysis of locomotor behavior helps in understanding the motor neuron disorders like Parkinson's Disease. Although many animal models are available to study the locomotion, adult zebrafish has emerged as a simple and efficient model to study this behavior. An inexpensive and easily customizable tool is required to replace the licensed and expensive set-up to analyse the locomotor behavior. NEW METHOD: In this study we have optimized the ImageJ plugin wrMTrck to analyse motor and non-motor behaviors in adult zebrafish. We have generated a macro to simplify the preprocessing and tracking. Subsequently, we have developed a data analysis sheet to analyse various behavioral end points. RESULTS: We have successfully developed an inexpensive video acquisition set-up and optimized wrMTrck for adult zebrafish. In order to demonstrate the efficacy of this method, adult zebrafish were injected with MPTP and motor and non-motor behaviors were analysed. Expectedly, MPTP injected fish showed decrease in dopamine level and dat expression level, which subsequently led to locomotor behavioral defects as well as anxiety, a non-motor symptom of PD. COMPARISON WITH EXISTING METHOD(S): Further, the obtained results were validated by another ImageJ macro developed by Pelkowski et al. (2011) and we observed identical trajectories. CONCLUSIONS: The usefulness of popular ImageJ plugin wrMTrck and this extended protocol will be helpful to quantify motor and non-motor behavioral parameters.

In vivo, in vitro and pharmacologic models of Parkinson's disease.

Parkinson's disease (PD), which is the second most common neurodegenerative disorder after Alzheimer's disease, is firstly defined after James Parkinson's report. It carries motor symptoms such as resting tremor, bradykinesia and rigidity of skeletal muscle and freezing of gait. Furthermore, non-motor symptoms such as cognitive and behavioral problems, besides sensory impairments are seen in the patients. However, they may also suffer from sleep disorders or autonomic dysfunction. Although there are some medications in order to symptomatic management, but unfortunately, scientist could not have found exact approaches to cure this disease. Hence, producing a model which can express the most pathophysiologic and behavioral aspects of the disease is a desire. In this paper, we aimed to describe the different models of Parkinson's disease in brief.

Neuroprotective effect of crocin on substantia nigra in MPTP-induced Parkinson's disease model of mice.

Parkinson's disease is caused by damage to substantia nigra dopaminergic neurons. Factors such as oxidative stress, inflammatory factors, and acetylcholinesterase activity may induce this disease. On the other hand, crocin-one of the active ingredients of saffron-has anti-oxidant and anti-inflammatory properties. This study was performed to evaluate the protective effect of crocin to decrease dopaminergic neuron damage and Parkinson's disease complications induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). A set of 24 male BALB/c Mice were divided randomly into four groups: (1) MPTP group receiving 30 mg/kg MPTP for 5 days; (2) MPTP + crocin group receiving 30 mg/kg MPTP for 5 days and 30 mg/kg crocin for 15 days; (3) NS group receiving normal saline for 5 days; and (4) NSIG group receiving normal saline intraperitoneally for 5 days and also normal saline by gavage for 15 days. After the treatment period, pole and hanging motor tests were performed in all groups. Then, the brains of all the animals were removed and fixed in formalin, prepared according to routine histologic methods and cut into sections of 5 µm thickness. Prepared sections were stained by immunohistochemistry techniques and toluidine blue to detect tyrosine-hydroxylase (TH)-positive neurons and dark neurons, respectively. Finally, the mean number of these cells were calculated by stereological methods and compared with the statistical tests in different groups. The results showed a significant increase in the time taken for the animal to fall from the pole in the MPTP group in comparison with other groups (P < 0.001). The time taken for them to stay on the wire in the hanging test decreased significantly in the MPTP group compared to the other groups (P < 0.001).,while in the MPTP + crocin group, the time to falling decreased (P < 0.05) and the time staying on the wire increased (P < 0.001) compared to the MPTP group. The number of TH-positive neurons in the MPTP group also decreased significantly in comparison with saline and MPTP + crocin groups (P < 0.001). The number of dark neuron sin the MPTP group increased significantly as compared with saline and the MPTP + Crocin groups (P < 0.001). Our results showed that crocin improves MPTP-induced Parkinson's disease complications and decreases cell death in the substantia nigra.

Enteric Neurodegeneration is Mediated Through Independent Neuritic and Somal Mechanisms in Rotenone and MPP+ Toxicity.

Gut motility malfunction and pathological changes in the enteric nervous system (ENS) are observed in the early stages of Parkinson's disease (PD). In many cases disturbances in the autonomous functions such as gut motility precedes the observed loss of central motor functions in PD. However, the mechanism by which ENS degeneration occurs in PD is unknown. We show that parkinsonian mimetics rotenone and MPP+ induce neurite degeneration that precedes cell death in primary enteric neurons cultured in vitro. If the neuronal death signals originate from degenerating neurites, neuronal death should be prevented by inhibiting neurite degeneration. Our data demonstrate that overexpression of cytNmnat1, an axon protector, maintains healthy neurites in enteric neurons treated with either of the parkinsonian mimetics, but cannot protect the soma. We also demonstrate that neurite protection via cytNmnat1 is independent of mitochondrial dynamics or ATP levels. Overexpression of Bcl-xl, an anti-apoptotic factor, protects both the neuronal cell body and the neurites in both rotenone and MPP+ treated enteric neurons. Our data reveals that Bcl-xl and cytNmnat1 act through separate mechanisms to protect enteric neurites. Our findings suggest that neurite protection alone is not sufficient to inhibit enteric neuronal degeneration in rotenone or MPP+ toxicity, and enteric neurodegeneration in PD may be occurring through independent somatic and neuritic mechanisms. Thus, therapies targeting both axonal and somal protection can be important in finding interventions for enteric symptoms in PD.

α-Synuclein disrupts the anti-inflammatory role of Drd2 via interfering ß-arrestin2-TAB1 interaction in astrocytes.

BACKGROUND: α-Synuclein (α-Syn)-induced neuroinflammation plays a crucial role in the pathogenesis of Parkinson's disease (PD). Dopamine D2 receptor (Drd2) has been regarded as a potential anti-inflammatory target in the therapy of neurodegenerative diseases. However, the effect of astrocytic Drd2 in α-Syn-induced neuroinflammation remains unclear. METHODS: The effect of Drd2 on neuroinflammation was examined in mouse primary astrocyte in vitro and A53T transgenic mice in vivo. The inflammatory responses of astrocyte were detected using immunofluorescence, ELISA, and qRT-PCR. The details of molecular mechanism were assessed using Western blotting and protein-protein interaction assays. RESULTS: We showed that the selective Drd2 agonist quinpirole suppressed inflammation in the midbrain of wild-type mice, but not in α-Syn-overexpressed mice. We also found that Drd2 agonists significantly alleviated LPS-induced inflammatory response in astrocytes, but failed to suppress α-Syn-induced inflammatory response. The anti-inflammation effect of Drd2 was dependent on ß-arrestin2-mediated signaling, but not classical G protein pathway. α-Syn reduced the expression of ß-arrestin2 in astrocytes. Increased the ß-arrestin2 expression restored in the anti-inflammation of Drd2 in α-Syn-induced inflammation. Furthermore, we demonstrated that α-Syn disrupted the anti-inflammation of Drd2 via inhibiting the association of ß-arrestin2 with transforming growth factor-beta-activated kinase 1 (TAK1)-binding protein 1 (TAB1) and promoting TAK1-TAB1 interaction in astrocytes. CONCLUSIONS: Our study illustrates that astrocytic Drd2 inhibits neuroinflammation through a ß-arrestin2-dependent mechanism and provides a new strategy for treatment of PD. Our findings also reveal that α-Syn disrupts the function of ß-arrestin2 and inflammatory pathways in the pathogenesis of PD.

Distribution of oxidized DJ-1 in Parkinson's disease-related sites in the brain and in the peripheral tissues: effects of aging and a neurotoxin.

DJ-1 plays an important role in antioxidant defenses, and a reactive cysteine at position 106 (Cys106) of DJ-1, a critical residue of its biological function, is oxidized under oxidative stress. DJ-1 oxidation has been reported in patients with Parkinson's disease (PD), but the relationship between DJ-1 oxidation and PD is still unclear. In the present study using specific antibody for Cys106-oxidized DJ-1 (oxDJ-1), we analyzed oxDJ-1 levels in the brain and peripheral tissues in young and aged mice and in a mouse model of PD induced using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). OxDJ-1 levels in the brain, heart, and skeletal muscle were high compared with other tissues. In the brain, oxDJ-1 was detected in PD-related brain sites such as the substantia nigra (SN) of the midbrain, olfactory bulb (OB), and striatum. In aged wild-type mice, oxDJ-1 levels in the OB, striatum, and heart tended to decrease, while those in the skeletal muscle increased significantly. Expression of dopamine-metabolizing enzymes significantly increased in the SN and OB of aged DJ-1-/- mice, accompanied by a complementary increase in glutathione peroxidase 1. MPTP treatment concordantly changed oxDJ-1 levels in PD-related brain sites and heart. These results indicate that the effects of physiological metabolism, aging, and neurotoxin change oxDJ-1 levels in PD-related brain sites, heart, and skeletal muscle where mitochondrial load is high, suggesting a substantial role of DJ-1 in antioxidant defenses and/or dopamine metabolism in these tissues.

Modulation of mitochondrial phenotypes by endurance exercise contributes to neuroprotection against a MPTP-induced animal model of PD.

AIM: Endurance exercise (EE) has been reported to confer neuroprotection against Parkinson's disease (PD); however, underlying molecular mechanisms of the protection remain still unclear. Since mitochondrial impairment is commonly observed in the brain of PD patients and animals, this study investigated whether EE-induced neuroprotection is associated with mitochondrial phenotypes, using a mouse model of PD induced by intraperitoneal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MAIN METHODS: SH-SY5Y cells were cultured with a neurotoxin MPP+ known to cause PD-like symptoms to examine if modifications of mitochondrial morphology are linked to etiology of PD. For in vivo experiments, C57BL/6 male mice were randomly assigned to four groups: control (CON, n = 12), endurance exercise (EXE, n = 12), MPTP (MPTP, n = 12) and MPTP plus endurance exercise (MPTP + EXE, n = 12). Mice assigned to endurance exercise performed treadmill running at 12 m/min for 60 min/day, 5 days/week for 6 weeks. KEY FINDINGS: SH-SY5Y cells exposed to a neurotoxin MPP+ exhibited mitochondrial fragmentation and diminished mitochondrial proteins, and cell death. Similarly, animals administered with MPTP displayed comparable impairments in the substantia nigra pars compacta (SNpc). In contrast, EE intervention restored motor function to control levels and reduced apoptosis. These propitious effects of EE were associated with mitochondrial phenotypic changes such as upregulated anti-apoptotic proteins (e.g., MCL-1 and BLC-2), reduced a pro-apoptotic protein (e.g., AIF), and improved mitochondrial biogenesis and fusion. SIGNIFICANCE: Our finding that EE-induced mitochondrial phenotypic changes that resist mitochondrial impairment and cell death against PD introduce potential insight into mitochondria as a new therapeutic target for PD.

Acute Restraint Stress Augments 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine Neurotoxicity via Increased Toxin Uptake into the Brain in C57BL/6 Mice.

As an environmental risk factor, psychological stress may trigger the onset or accelerate the progression of Parkinson's disease (PD). Here, we evaluated the effects of acute restraint stress on striatal dopaminergic terminals and the brain metabolism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which has been widely used for creating a mouse model of PD. Exposure to 2 h of restraint stress immediately after injection of a low dose of MPTP caused a severe loss of striatal dopaminergic terminals as indicated by decreases in the dopamine transporter protein and dopamine levels compared with MPTP administration alone. Both striatal 1-methyl-4-phenylpyridinium ion (MPP+) and MPTP concentrations were significantly increased by the application of restraint stress. Striatal monoamine oxidase-B, which catalyzes the oxidation of MPTP to MPP+, was not changed by the restraint stress. Our results indicate that the enhanced striatal dopaminergic terminal loss in the stressed mice is associated with an increase in the transport of neurotoxin into the brain.

Oligo-Porphyran Ameliorates Neurobehavioral Deficits in Parkinsonian Mice by Regulating the PI3K/Akt/Bcl-2 Pathway.

Parkinson's disease (PD) is a neurodegenerative movement disorder that is caused by a selective loss of dopaminergic neurons. Current PD treatments provide symptomatic relief but do not prevent or decelerate disease progression. Previous studies have suggested that acetylated and phosphorylated porphyran, derived from Porphyra, produces a neuroprotective effect against 6-OHDA-induced damage. Due to its antioxidant and neuroprotective potential, this study evaluates whether oligo-porphyran (OP) could be beneficial in an experimental model of PD in mice. The drug 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was intraperitoneally injected (20 mg/kg body weight) for seven days to simulate PD, followed by OP administration. We found that the behavioral deficits in spontaneous motor activity, latency to descend in a pole test, and suspension in a traction test were ameliorated, and excessive dopamine (DA) metabolism was suppressed after OP treatment. Additionally, we found that OP protected dopaminergic neurons by preventing MPTP-induced decreases in dopaminergic transporter and tyrosine hydroxylase protein levels. We speculated whether OP regulates a signaling pathway that affects the behavioral changes seen in PD mice. In this study, the PI3K/Akt/Bcl-2 pathway was detected. Our results demonstrate that OP increased the phosphorylation of PI3K/Akt/GSK-3ß and inhibited the activation of caspase-3 and poly (ADP-ribose) polymerase, with changes in the Bax/Bcl-2 ratio. These results showed that OP might promote DA neuron survival in vivo by regulating the PI3K/Akt/Bcl-2 pathway, thereby ameliorating the neurobehavioral deficits in a PD mouse model and suggesting OP as a neuroprotective treatment for PD.

Pharmacokinetics and Toxicology of the Neuroprotective e,e,e-Methanofullerene(60)-63-tris Malonic Acid [C3] in Mice and Primates.

BACKGROUND AND OBJECTIVES: Fullerene-based compounds are a novel class of molecules being developed for a variety of biomedical applications, with nearly 1000 publications in this area in the last 4 years alone. One such compound, the e,e,e-methanofullerene(60)-63-tris malonic acid (designated C3), is a potent catalytic superoxide dismutase mimetic which has shown neuroprotective efficacy in a number of animal models of neurologic disease, including Parkinsonian Macaca fascicularis monkeys. The aim of this study was to characterize its toxicity and pharmacokinetics in mice and monkeys. METHODS: To assess pharmacokinetics in mice, we synthesized and administered 14C-C3 to mice using various routes of delivery, including orally. To assess potential toxicity in primates, serial blood studies and electrocardiograms (ECGs) were obtained from monkeys treated with C3 (3 or 7 mg/kg/day) for 2  months. RESULTS AND CONCLUSIONS: The plasma half-life of C3 was 8.2 ± 0.2 h, and there was wide tissue distribution, including uptake into brain. The compound was cleared by both hepatic and renal excretion. C3 was quite stable, with minimal metabolism of the compound even after 7 days of treatment. The LD50 in mice was 80 mg/kg for a single intraperitoneal injection, and was > 30 mg/kg/day for sustained administration; therapeutic doses are 1-5 mg/kg/day. For primates, no evidence of renal, hepatic, electrolyte, or hematologic abnormalities were noted, and serial ECGs demonstrated no alteration in cardiac electrical activity. Thus, doses of C3 that have therapeutic efficacy appear to be well tolerated after 2 years (mice) or 2 months (non-human primates) of treatment.