The protective effects of repetitive transcranial magnetic stimulation with different high frequencies on motor functions in MPTP/probenecid induced Parkinsonism mouse models.

BACKGROUND: High-frequency repeated transcranial magnetic stimulation (rTMS) stimulating the primary motor cortex (M1) is an alternative, adjunctive therapy for improving the motor symptoms of Parkinson's disease (PD). However, whether the high frequency of rTMS positively correlates to the improvement of motor symptoms of PD is still undecided. By controlling for other parameters, a disease animal model may be useful to compare the neuroprotective effects of different high frequencies of rTMS. OBJECTIVE: The current exploratory study was designed to compare the protective effects of four common high frequencies of rTMS (5, 10, 15, and 20 Hz) and iTBS (a special form of high-frequency rTMS) and explore the optimal high-frequency rTMS on an animal PD model. METHODS: Following high frequencies of rTMS application (twice a week for 5 weeks) in a MPTP/probenecid-induced chronic PD model, the effects of the five protocols on motor behavior as well as dopaminergic neuron degeneration levels were identified. The underlying molecular mechanisms were further explored. RESULTS: We found that all the high frequencies of rTMS had protective effects on the motor functions of PD models to varying degrees. Among them, the 10, 15, and 20 Hz rTMS interventions induced comparable preservation of motor function through the protection of nigrostriatal dopamine neurons. The enhancement of brain-derived neurotrophic factor (BDNF), dopamine transporter (DAT), and vesicular monoamine transporter 2 (VMAT-2) and the suppression of TNF-α and IL-1ß in the nigrostriatum were involved in the process. The efficacy of iTBS was inferior to that of the above three protocols. The effect of 5 Hz rTMS protocol was weakest. CONCLUSIONS: Combined with the results of the present study and the possible side effects induced by rTMS, we concluded that 10 Hz might be the optimal stimulation frequency for preserving the motor functions of PD models using rTMS treatment.

Delivery of CDNF by AAV-mediated gene transfer protects dopamine neurons and regulates ER stress and inflammation in an acute MPTP mouse model of Parkinson's disease.

Cerebral dopamine neurotrophic factor (CDNF) and its close structural relative, mesencephalic astrocyte-derived neurotrophic factor (MANF), are proteins with neurotrophic properties. CDNF protects and restores the function of dopamine (DA) neurons in rodent and non-human primate (NHP) toxin models of Parkinson's disease (PD) and therefore shows promise as a drug candidate for disease-modifying treatment of PD. Moreover, CDNF was found to be safe and to have some therapeutic effects on PD patients in phase 1/2 clinical trials. However, the mechanism underlying the neurotrophic activity of CDNF is unknown. In this study, we delivered human CDNF (hCDNF) to the brain using an adeno-associated viral (AAV) vector and demonstrated the neurotrophic effect of AAV-hCDNF in an acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD. AAV-hCDNF resulted in the expression of hCDNF in the striatum (STR) and substantia nigra (SN), and no toxic effects on the nigrostriatal pathway were observed. Intrastriatal injection of AAV-hCDNF reduced motor impairment and partially alleviated gait dysfunction in the acute MPTP mouse model. In addition, gene therapy with AAV-hCDNF had significant neuroprotective effects on the nigrostriatal pathway and decreased the levels of interleukin 1beta (IL-1ß) and complement 3 (C3) in glial cells in the acute MPTP mouse model. Moreover, AAV-hCDNF reduced C/EBP homologous protein (CHOP) and glucose regulatory protein 78 (GRP78) expression in astroglia. These results suggest that the neuroprotective effects of CDNF may be mediated at least in part through the regulation of neuroinflammation and the UPR pathway in a mouse MPTP model of PD in vivo.

Human neural stem cells promote mitochondrial genesis to alleviate neuronal damage in MPTP-induced cynomolgus monkey models.

Currently, there is no effective treatment for Parkinson's disease (PD), and the regenerative treatment of neural stem cells (NSCs) is considered the most promising method. This study aimed to investigate the protective effect and mechanism of NSCs on neurons in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) induced cynomolgus monkey (Macaca fascicularis) model of PD. We first found that injecting NSCs into the subarachnoid space relieved motor dysfunction in PD cynomolgus monkeys, as well as reduced dopaminergic neuron loss and neuronal damage in the substantia nigra (SN) and striatum. Besides, NSCs decreased 17-estradiol (E2) level, an estrogen, in the cerebrospinal fluid (CSF) of PD cynomolgus monkeys, which shows NSCs may provide neuro-protection by controlling estrogen levels in the CSF. Furthermore, NSCs elevated proliferator-activated receptor gamma coactivator-1 alpha (PGC-1a), mitofusin 2 (MFN2), and optic atrophy 1 (OPA1) expression, three genes mediating mitochondrial biogenesis, in the SN and striatum of PD monkeys. In addition, NSCs suppress reactive oxygen species (ROS) production caused by MPTP, as well as mitochondrial autophagy, therefore preserving dopaminergic neurons. In summary, our findings show that NSCs may preserve dopaminergic and neuronal cells in an MPTP-induced PD cynomolgus monkey model. These protective benefits might be attributed to NSCs' ability of modulating estrogen balance, increasing mitochondrial biogenesis, and limiting oxidative stress and mitochondrial autophagy. These findings add to our understanding of the mechanism of NSC treatment and shed light on further clinical treatment options.

Mesenchymal stem-cell-derived microvesicles ameliorate MPTP-induced neurotoxicity in mice: a role of the gut-microbiota-brain axis.

RATIONALE: Parkinson's disease (PD) is a chronic and progressive neurodegenerative disorder. Increasing evidence suggests the role of the gut-microbiota-brain axis in the pathogenesis of PD. Mesenchymal stem-cell-derived microvesicles (MSC-MVs) have emerged as a therapeutic potential for neurological disorders over the last years. OBJECTIVE: The objective of this study was to investigate whether MSC-MVs could improve PD-like neurotoxicity in mice after administration of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine). RESULTS: MPTP-induced reductions in the dopamine transporter and tyrosine hydroxylase expressions in the striatum and substantia nigra (SNr) were attenuated after a subsequent single administration of MSC-MVs. Increases in the phosphorylated α-synuclein (p-α-Syn)/α-Syn ratio in the striatum, SNr, and colon after MPTP injection were also attenuated after MSC-MVs injection. Furthermore, MSC-MVs restored MPTP-induced abnormalities of the gut microbiota composition. Interestingly, positive correlations between the genus Dubosiella and the p-α-Syn/α-Syn ratio were observed in the brain and colon, suggesting their roles in the gut-microbiota-brain communication. Moreover, MSC-MVs attenuated MPTP-induced reduction of the metabolite, 3,6-dihydroxy-2-[3-methoxy-4-(sulfooxy)phenyl]-7-(sulfinooxy)-3,4-dihydro-2H-1-benzopyran-5-olate, in the blood. Interestingly, a negative correlation between this compound and the p-α-Syn/α-Syn ratio was observed in the brain and colon. CONCLUSIONS: These data suggest that MSC-MVs could ameliorate MPTP-induced neurotoxicity in the brain and colon via the gut-microbiota-brain axis. Therefore, MSC-MVs would have a new therapeutic potential for neurological disorders such as PD.

Hyperbaric Oxygen Therapy Improves Parkinson's Disease by Promoting Mitochondrial Biogenesis via the SIRT-1/PGC-1α Pathway.

Hyperbaric oxygen therapy (HBOT) has been suggested as a potential adjunctive therapy for Parkinson's disease (PD). PD is a neurodegenerative disease characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The aim of this study was to investigate the protective mechanisms of HBOT on neurons and motor function in a 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD and 1-methyl-4-phenylpyridinium (MPP+)-mediated neurotoxicity in SH-SY5Y cells on the potential protective capability. In vivo: male C57BL/6 mice were randomly divided into three groups: control, MPTP group and MPTP+HBOT group. The MPTP-treated mice were intraperitoneally received MPTP (20 mg/kg) four times at 2 h intervals within a day. The day after MPTP treatment, MPTP+HBOT mice were exposed to hyperbaric oxygen at 2.5 atmosphere absolute (ATA) with 100% oxygen for 1 h once daily for 7 consecutive days. In vitro: retinoic acid (RA)-differentiated SH-SY5Y cells were treated with MPP+ for 1 h followed by hyperbaric oxygen at 2.5 ATA with 100% oxygen for 1 h. The results showed that MPTP induced a significant loss in tyrosine hydroxylase (TH)-positive neurons in the SNpc of mice. HBOT treatment significantly increased the number of TH-positive neurons, with enhanced neurotrophic factor BDNF, decreased apoptotic signaling and attenuated inflammatory mediators in the midbrain of MPTP-treated mice. In addition, MPTP treatment decreased the locomotor activity and grip strength of mice, and these effects were shown to improve after HBOT treatment. Furthermore, MPTP decreased mitochondrial biogenesis signaling (SIRT-1, PGC-1α and TFAM), as well as mitochondrial marker VDAC expression, while HBOT treatment was shown to upregulate protein expression. In cell experiments, MPP+ reduced neurite length, while HBOT treatment attenuated neurite retraction. Conclusions: the effects of HBOT in MPTP-treated mice might come from promoting mitochondrial biogenesis, decreasing apoptotic signaling and attenuating inflammatory mediators in the midbrain, suggesting its potential benefits in PD treatment.

Treadmill exercise alleviates neuronal damage by suppressing NLRP3 inflammasome and microglial activation in the MPTP mouse model of Parkinson's disease.

Treadmill exercise has been recognized as an effectively therapeutic strategy for Parkinson's disease (PD). However, its exact molecular mechanism of promoting PD remain unclear. Recently, the NLRP3 inflammasome is considered to play a critical role in the pathogenesis of PD. In this study, we investigated whether NLRP3 inflammasome was involved in treadmill exercise-induced neuroprotection and anti-inflammation effect in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD. 8-week-old male mice (C57BL/6 strain) were divided into four groups: Control, MPTP, MPTP + EX and EX. MPTP was intraperitoneally injected into mice to establish chronic PD model. The open-field test and pole test were used to assess motor function. The results showed that treadmill exercise significantly alleviated motor dysfunction and dopaminergic neuron degeneration induced by MPTP. In addition, we also found that treadmill exercise suppressed MPTP-triggered microglia activation and the co-localization of NLRP3+/Iba-1+ cells in the substantia nigra. These effects were associated with suppression NLRP3 inflammasome via down-regulation of TLR4/MyD88/NF-κB pathway. Overall, our study demonstrated that treadmill exercise could effectively alleviates neuronal damage via inhibition of NLRP3 inflammasome and microglial activation in MPTP-induced PD mouse model.

Endurance exercise training suppresses Parkinson disease-induced overexpression of apoptotic mediators in the heart.

BACKGROUNDWe have shown elevated levels of p53 and active caspase-3 in the heart with Parkinson disease (PD). The main aim of this study is to examine the effect of treadmill training on the cardiac expression of p53 and active caspase-3 in the mouse with induced Parkinsonism. METHODS: Thirty randomly selected normal albino mice were equally divided into the following 3 groups: sedentary control (SC), sedentary Parkinson diseased (SPD), and exercised Parkinson diseased (EPD). 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTP/p) were used to induce chronic Parkinson disease in the SPD and EPD animals. The expression of p53 and active caspase-3 was investigated, using immunohistochemistry, in the heart in each animal group. RESULTS: Both p53 and active caspase-3 expression was significantly (p value < 0.05) reduced in the PD heart following endurance exercise training. CONCLUSION: Our present data suggest that chronic exercise training reduced PD-induced upregulation of p53 and active caspase-3 in the heart. Thus, our study suggests that inhibiting p53 and/or active caspase-3 may be considered as a therapeutic approach to ameliorate PD cardiomyopathy.

Potential therapeutic role of fibroblast growth factor 21 in neurodegeneration: Evidence for ameliorating parkinsonism via silent information regulator 2 homolog 1 and implication for gene therapy.

Parkinson's disease (PD) is one of the common complex neurodegenerative diseases and characterized by abnormal metabolic brain networks. Fibroblast growth factor 21 (FGF21), an endocrine hormone that belongs to the fibroblast growth factor superfamily, plays an extensive role in the regulation of metabolism. However, our understandings of the specific function and mechanisms of FGF21 on PD are still quite limited. Here we aimed to elucidate the actions and the underlying mechanisms of FGF21 on dopaminergic neurodegeneration using cellular and animal models of parkinsonism. To investigate the effects of FGF21 on dopaminergic neurodegeneration in vivo and in vitro, 1-methyl-4-phenyl-1,2,3,6- tetrahydropyridine models of PD were utilized, and animals were treated with recombinant FGF21 protein or FGF21 gene delivered via an adeno-associated virus. In the present study, systemic and continuous intracerebroventricular recombinant FGF21 protein administration to mice both prevented behavioral deficits, protected dopaminergic neurons against degeneration, and ameliorated α-synuclein pathology in PD models; and in vivo gene delivery of FGF21 improved PD-like symptoms and pathologies suggesting a potential implication of FGF21 in gene therapy for PD. In vitro evidence confirmed FGF21 mediated neuroprotective benefits against PD pathologies. Further, our data suggested that enhanced autophagy was involved in the FGF21 neuroprotection in PD models, and silent information regulator 2 homolog 1 may play a crucial role in molecular mechanisms underlying anti-PD activities of FGF21.

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.

Development of a novel gripping test for the evaluation of the finger fine motor ability in MPTP-treated monkeys.

Assessing the finger fine motor ability is extremely important. However, conventional behavioral tests in monkeys are complicated and costly. We attempted to develop a new task to assess the precise finger grip in Parkinson's disease monkeys based on the principles of objectification, multipurpose, and simplification. This study involved seven adult male cynomolgus monkeys. A gripping test based on the previous food reaching test was developed. Parallel experiments of food reaching test and gripping test affected by the treatments of levodopa and deep brain stimulation of the subthalamic nucleus were performed to verify the utility of the gripping test. We found that gross motor ability (measured by food reaching test) could be significantly improved by both the subthalamic nucleus and levodopa administration, which reproduced the results of our previous study. The finger fine motor ability (measured by the gripping test) could be significantly improved by levodopa administration, but not by the subthalamic nucleus. Our results verified the utility and reliability of the gripping test, which is a simple, convenient, and objective task for evaluating the finger fine motor skill in Parkinson's disease monkeys. Mechanisms of the efficacy of deep brain stimulation on fine motor ability require further investigation.

A Gutsy Move for Cell-Based Regenerative Medicine in Parkinson's Disease: Targeting the Gut Microbiome to Sequester Inflammation and Neurotoxicity.

Pharmaceuticals and cell-based regenerative medicine for Parkinson's disease (PD) offer palliative relief but do not arrest the disease progression. Cell therapy has emerged as an experimental treatment, but current cell sources such as human umbilical cord blood (hUCB) stem cells display only partial recapitulation of mature dopaminergic neuron phenotype and function. Nonetheless, stem cell grafts ameliorate PD-associated histological and behavioral deficits likely through stem cell graft-secreted therapeutic substances. We recently demonstrated the potential of hUCB-derived plasma in enhancing motor capabilities and gastrointestinal function, as well as preventing dopaminergic neuronal cell loss, in an 1-methyl-4-phenyl-1,2,3,6-tetrahydro-pyridine (MPTP) rodent model of PD. Recognizing the translational need to test in another PD model, we now examined here the effects of an intravenously transplanted combination of hUCB and plasma into the 6-hydroxydopamine (6-OHDA) lesioned adult rats. Animals received three separate doses of 4 × 106 hUCB cells with plasma beginning at 7 days after stereotaxic 6-OHDA lesion, then behaviorally and immunohistochemically evaluated over 56 days post-lesion. Whereas vehicle-treated lesioned animals exhibited the typical 6-OHDA neurobehavioral symptoms, hUCB and plasma-treated lesioned animals showed significant attenuation of motor function, gut motility, and nigral dopaminergic neuronal survival, combined with diminished pro-inflammatory microbiomes not only in the nigra, but also in the gut. Altogether these data support a regenerative medicine approach for PD by sequestering inflammation and neurotoxicity through correction of gut dysbiosis.

Knockdown of TRB3 improved the MPP+/MPTP-induced Parkinson's disease through the MAPK and AKT signaling pathways.

This study aims to investigate the function and molecular mechanisms of Tribbles homolog 3 (TRB3) on the MPP+/MPTP-induced Parkinson's disease (PD). In this study, MPP+-induced PD cellular model and MPTP-caused PD mice model were established. Following the transfection with TRB3-shRNA, cell viability, cell apoptosis, ROS level, and the ratio of p-p38/ p38, p-JNK/JNK, p-AKT/AKT were examined. At the same time, behavior assessment of wild type female C57BL/6 mice and whole-body TRB3 knockout mice PD models caused by MPTP were performed by Rotarod test and Open-field test. The results showed that TRB3 was markedly upregulated in MPP+-induced cellular model through ATF4/CHOP pathway. Knockdown of TRB3 significantly decreased the MPP+-induced reduction of cell viability, augment of cell apoptosis and accumulation of ROS, inhibited the phosphorylation of p38 and JNK, and promoted the phosphorylation of AKT, in vitro. Further, knockout of TRB3 improved the behavior impairment of PD mice induced by MPTP, in vivo. In conclusion, knockdown of TRB3 has a neuroprotective effect on MPTP/MPP+-induced PD cellular and mice models, through regulating MAPK and AKT signaling pathways.

Neuroprotective effect of anodal transcranial direct current stimulation on 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in mice through modulating mitochondrial dynamics.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the accumulation of protein inclusions and the loss of dopaminergic neurons. Abnormal mitochondrial homeostasis is thought to be important for the pathogenesis of PD. Transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, constitutes a promising approach for promoting recovery of various neurological conditions. However, little is known about its mechanism of action. The present study elucidated the neuroprotective effects of tDCS on the mitochondrial quality control pathway in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse model. We used the MPTP-induced neurotoxicity in vivo model. Mice were stimulated for 5 consecutive days with MPTP treatment. After observation of behavioral alteration using the rotarod test, mice were sacrificed for the measurement of the PD- and mitochondrial quality control-related protein levels in the substantia nigra. tDCS improved the behavioral alterations and changes in tyrosine hydroxylase levels in MPTP-treated mice. Furthermore, tDCS attenuated mitochondrial damage, as indicated by diminished mitochondrial swelling and mitochondrial glutamate dehydrogenase activity in the MPTP-induced PD mouse model. MPTP significantly increased mitophagy and decreased mitochondrial biogenesis-related proteins. These changes were attenuated by tDCS. Furthermore, MPTP significantly increased fission-related protein dynamin-related protein 1 with no effect on fusion-related protein mitofusin-2, and tDCS attenuated these changes. Our findings demonstrated the neuroprotective effect of anodal tDCS on the MPTP-induced neurotoxic mouse model through suppressing excessive mitophagy and balancing mitochondrial dynamics. The neuroprotective effect of anodal tDCS with modulation of mitochondrial dynamics provides a new therapeutic strategy for the treatment of PD.

Fine Manual Dexterity Assessment After Autologous Neural Cell Ecosystem (ANCE) Transplantation in a Non-human Primate Model of Parkinson's Disease.

Background. Autologous neural cell ecosystem (ANCE) transplantation improves motor recovery in MPTP monkeys. These motor symptoms were assessed using semi-quantitative clinical rating scales, widely used in many studies. However, limitations in terms of sensitivity, combined with relatively subjective assessment of their different items, make inter-study comparisons difficult to achieve. Objective. The aim of this study was to quantify the impact of MPTP intoxication in macaque monkeys on manual dexterity and assess whether ANCE can contribute to functional recovery. Methods. Four animals were trained to perform 2 manual dexterity tasks. After reaching a motor performance plateau, the animals were subjected to an MPTP lesion. After the occurrence of a spontaneous functional recovery plateau, all 4 animals were subjected to ANCE transplantation. Results. Two of 4 animals underwent a full spontaneous recovery before the ANCE transplantation, whereas the 2 other animals (symptomatic) presented moderate to severe Parkinson's disease (PD)-like symptoms affecting manual dexterity. The time to grasp small objects using the precision grip increased in these 2 animals. After ANCE transplantation, the 2 symptomatic animals underwent a significant functional recovery, reflected by a decrease in time to execute the different tasks, as compared with the post-lesion phase. Conclusions. Manual dexterity is affected in symptomatic MPTP monkeys. The 2 manual dexterity tasks reported here as pilot are pertinent to quantify PD symptoms and reliably assess a treatment in MPTP monkeys, such as the present ANCE transplantation, to be confirmed in a larger cohort of animals before future clinical applications.

Physical activity sustains memory retrieval in dopamine-depleted mice previously treated with L-Dopa.

The neurodegenerative disorder Parkinson's disease affects motor abilities as well as cognition. The gold standard therapy is L-Dopa, which mainly restores motor skills. Therefore, we require additional interventions to sustain cognitive functions in Parkinson's disease. The lifestyle intervention "physical activity" improves adult hippocampal neurogenesis and memory but so far, its impact has not been investigated in rodent models for Parkinson's disease previously treated with the standard therapy. We hereby asked whether physical activity serves as a pro-neurogenic and -cognitive stimulus in dopamine-depleted mice previously treated with L-Dopa. Therefore, we injected dopamine-depleted mice with L-Dopa/Benserazide followed either by exercise or by a sedentary lifestyle. We analysed adult hippocampal neurogenesis histologically and assessed spatial memory in the Morris water maze. Furthermore, we investigated the hippocampal and striatal monoaminergic cross-talk. Physical activity prevented memory decline and was linked to a slower dopamine turnover but did not enhance neurogenesis in dopamine-depleted mice previously treated with L-Dopa. In conclusion, physical activity did not develop its full pro-neurogenic potential in mice previously treated with L-Dopa but sustained spatial cognition in Parkinson's disease.

Deciduous DPSCs Ameliorate MPTP-Mediated Neurotoxicity, Sensorimotor Coordination and Olfactory Function in Parkinsonian Mice.

Parkinson's disease (PD) is a neurodegenerative disorder defined by progressive deterioration of dopaminergic neurons in the substantia nigra pars compacta (SNpc). Dental pulp stem cells (DPSCs) have been proposed to replace the degenerated dopaminergic neurons due to its inherent neurogenic and regenerative potential. However, the effective delivery and homing of DPSCs within the lesioned brain has been one of the many obstacles faced in cell-based therapy of neurodegenerative disorders. We hypothesized that DPSCs, delivered intranasally, could circumvent these challenges. In the present study, we investigated the therapeutic efficacy of intranasally administered DPSCs in a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of PD. Human deciduous DPSCs were cultured, pre-labelled with PKH 26, and intranasally delivered into PD mice following MPTP treatment. Behavioural analyses were performed to measure olfactory function and sensorimotor coordination, while tyrosine hydroxylase (TH) immunofluorescence was used to evaluate MPTP neurotoxicity in SNpc neurons. Upon intranasal delivery, degenerated TH-positive neurons were ameliorated, while deterioration in behavioural performances was significantly enhanced. Thus, the intranasal approach enriched cell delivery to the brain, optimizing its therapeutic potential through its efficacious delivery and protection against dopaminergic neuron degeneration.

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.

Endurance Exercise Mediates Neuroprotection Against MPTP-mediated Parkinson's Disease via Enhanced Neurogenesis, Antioxidant Capacity, and Autophagy.

Parkinson's disease (PD) is a neurodegenerative disorder caused by loss of dopaminergic neurons in the substantia nigra, leading to motor dysfunction. Growing evidence has demonstrated that endurance exercise (EE) confers neuroprotection against PD. However, the exact molecular mechanisms responsible for exercise-induced protection of dopaminergic neurons in PD remain unclear. Since oxidative stress plays a key role in the degenerative process of PD. We investigated whether EE-induced neuroprotection is associated with enhanced antioxidative capacity and autophagy, using a mouse model of PD induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration. C57BL/6 male mice were randomly assigned to four groups: control (CON, n = 12), exercise (EXE, n = 12), MPTP (MPTP, n = 12) and MPTP + exercise (MPTP + EXE, n = 12). Our data demonstrated that while MPTP treatment impaired motor function, EE restored MPTP-induced motor deficits. Our biochemical data showed that EE-induced neuroprotection occurs in combination with multiple synergic neuroprotective pathways: (1) increased neurogenesis shown by an increase in BrdU-positive neurons; (2) diminished loss of dopaminergic neurons evidenced by upregulated tyrosine hydroxylase (TH) and dopamine transporter (DAT) levels; (3) increased antioxidant capacity (e.g., CuZnSOD, CATALASE, GPX1/2, HO-1, DJ1 and PRXIII); and (4) enhanced autophagy (LC3 II, p62, BECLIN1, BNIP3, LAMP2, CATHEPSIN L and TFEB). Our study suggests that EE-induced multiple synergic protective pathways including enhanced neurogenesis, antioxidative capacity, and concordant autophagy promotion contribute to restoration of impaired dopaminergic neuronal function caused by PD. Thus, PD patients should be encouraged to actively participate in regular EE as a potent nonpharmacological therapeutic strategy against PD.

Evidence for encephalopsin immunoreactivity in interneurones and striosomes of the monkey striatum.

In this study, we examined the cellular distribution of encephalopsin (opsin 3; OPN3) expression in the striatum of non-human primates. In addition, because of our long standing interest in Parkinson's disease and neuroprotection, we examined whether parkinsonian (MPTP; 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) insult and/or photobiomodulation (670 nm) had any impact on encephalopsin expression in this key area of the basal ganglia. Striatal sections of control naïve monkeys, together with those that were either MPTP- and/or photobiomodulation-treated were processed for immunohistochemistry. Our results revealed two populations of striatal interneurones that expressed encephalopsin, one of which was the giant, choline acetyltransferase-containing, cholinergic interneurones. The other population had smaller somata and was not cholinergic. Neither cell group expressed the calcium-binding protein, parvalbumin. There was also rich encephalopsin expression in a set of terminals forming striosome-like patches across the striatum. Finally, we found that neither parkinsonian (MPTP) insult nor photobiomodulation had any effect on encephalopsin expression in the striatum. In summary, our results revealed an extensive network of encephalopsin containing structures throughout the striatum, indicating that external light is in a position to influence a range of striatal activities at both the interneurone and striosome level.

Immunization with α-synuclein/Grp94 reshapes peripheral immunity and suppresses microgliosis in a chronic Parkinsonism model.

Neuroinflammation mediated by chronically activated microglia, largely caused by abnormal accumulation of misfolded α-synuclein (αSyn) protein, is known to contribute to the pathophysiology of Parkinson's disease (PD). In this work, based on the immunomodulatory activities displayed by particular heat-shock proteins (HSPs), we tested a novel vaccination strategy that used a combination of αSyn and Grp94 (HSPC4 or Gp96) chaperone and a murine PD model. We used two different procedures, first, the adoptive transfer of splenocytes from αSyn/Grp94-immunized mice to recipient animals, and second, direct immunization with αSyn/Grp94, to study the effects in a chronic mouse MPTP-model of parkinsonism. We found that both approaches promoted a distinct profile in the peripheral system-supported by humoral and cellular immunity-consisting of a Th1-shifted αSyn-specific response accompanied by an immune-regulatory/Th2-skewed general phenotype. Remarkably, this mixed profile sustained by αSyn/Grp94 immunization led to strong suppression of microglial activation in the substantia nigra and striatum, pointing to a newly described positive effect of anti-αSyn Th1-responses in the context of PD. This strategy is the first to target αSyn and report the suppression of PD-associated microgliosis. Overall, we show that the αSyn/Grp94 combination supports a distinct and long-lasting immune profile in the peripheral system, which has an impact at the CNS level by suppressing chronic microglial activation in an MPTP model of PD. Furthermore, our study demonstrates that reshaping peripheral immunity by vaccination with appropriate misfolding protein/HSP combinations could be highly beneficial as a treatment for neurodegenerative misfolding diseases.