6-Shogaol,an active compound of ginger,protects dopaminergic neurons in Parkinson's disease models via anti-neuroinflammation

Aim:

6-Shogaol [1-(4-hydroxy-methoxyphenyl)-4-decen-one], a pungent compound isolated from ginger, has shown various neurobiological and anti-inflammatory effects. The aim of this study was to examine the effects of 6-shogaol on neuroinflammatory-induced damage of dopaminergic (DA) neurons in Parkinson''s disease (PD) models.

Methods:

Cultured rat mesencephalic cells were treated with 6-shogaol (0.001 and 0.01 μmol/L) for 1 h, then with MPP⁺(10 μmol/L) for another 23 h. The levels of TNF-α and NO in medium were analyzed spectrophotometrically. C57/BL mice were administered 6-shogaol (10 mg·kg⁻¹·d⁻¹, po) for 3 d, and then MPTP (30 mg/kg, ip) for 5 d. Seven days after the last MPTP injection, behavioral testings were performed. The levels of tyrosine hydroxylase (TH) and macrophage antigen (MAC)-1 were determined with immunohistochemistry. The expression of iNOS and COX-2 was measured using RT PCR.

Results:

In MPP⁺-treated rat mesencephalic cultures, 6-shogaol significantly increased the number of TH-IR neurons and suppressed TNF-α and NO levels. In C57/BL mice, treatment with 6-shogaol reversed MPTP-induced changes in motor coordination and bradykinesia. Furthermore, 6-shogaol reversed MPTP-induced reductions in TH-positive cell number in the substantia nigra pars compacta (SNpc) and TH-IR fiber intensity in stratum (ST). Moreover, 6-shogaol significantly inhibited the MPTP-induced microglial activation and increases in the levels of TNF-α, NO, iNOS, and COX-2 in both SNpc and ST.

Conclusion:

6-Shogaol exerts neuroprotective effects on DA neurons in in vitro and in vivo PD models.     

Ginsenoside Rg1 protects dopaminergic neurons in a rat model of Parkinson's disease through the IGF-I receptor signalling pathway

Background and purpose:

We have shown that ginsenoside Rg1 is a novel class of potent phytoestrogen and activates insulin-like growth factor-I receptor (IGF-IR) signalling pathway in human breast cancer MCF-7 cells. The present study tested the hypothesis that the neuroprotective actions of Rg1 involved activation of the IGF-IR signalling pathway in a rat model of Parkinson''s disease, induced by 6-hydroxydopamine (6-OHDA).

Experimental approach:

Ovariectomized rats were infused unilaterally with 6-OHDA into the medial forebrain bundle to lesion the nigrostriatal dopamine pathway and treated with Rg1 (1.5 h after 6-OHDA injections) in the absence or presence of the IGF-IR antagonist JB-1 (1 h before Rg1 injections). The rotational behaviour induced by apomorphine and the dopamine content in the striatum were studied. Protein and gene expression of tyrosine hydroxylase, dopamine transporter and Bcl-2 in the substantia nigra were also determined.

Key results:

Rg1 treatment ameliorated the rotational behaviour induced by apomorphine in our model of nigrostriatal injury. This effect was partly blocked by JB-1. 6-OHDA significantly decreased the dopamine content of the striatum and treatment with Rg1 reversed this decrease. Treatment with Rg1 of 6-OHDA-lesioned rats reduced neurotoxicity, as measured by tyrosine hydroxylase, dopamine transporter and Bcl-2 protein and gene level in the substantia nigra. These effects were abolished by JB-1.

Conclusions and implications:

These data provide the first evidence that Rg1 has neuroprotective effects on dopaminergic neurons in the 6-OHDA model of nigrostriatal injury and its actions might involve activation of the IGF-IR signalling pathway.     

The PPARgamma agonist pioglitazone is effective in the MPTP mouse model of Parkinson's disease through inhibition of monoamine oxidase B

BACKGROUND AND PURPOSE: The peroxisome proliferator-activated receptor-gamma (PPARgamma) agonist pioglitazone has previously been shown to attenuate dopaminergic cell loss in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease, an effect attributed to its anti-inflammatory properties. In the present investigation, we provide evidence that pioglitazone is effective in the MPTP mouse model, not via an anti-inflammatory action, but through inhibition of MAO-B, the enzyme required to biotransform MPTP to its active neurotoxic metabolite 1-methyl-4-phenylpyridinium (MPP+). EXPERIMENTAL APPROACH: Mice were treated with pioglitazone (20 mg kg(-1) b.i.d. (twice a day), p.o., for 7 days), prior and post or post-MPTP (30 mg kg(-1) s.c.) treatment. Mice were then assessed for motor impairments on a beam-walking apparatus and for reductions in TH immunoreactivity in the substantia nigra and depletions in striatal dopamine. The effects of pioglitazone on striatal MPP+ levels and MAO-B activity were also assessed. KEY RESULTS: Mice treated with MPTP showed deficits in motor performance, marked depletions in striatal dopamine levels and a concomitant reduction in TH immunoreactivity in the substantia nigra. Pretreatment with pioglitazone completely prevented these effects of MPTP. However, pretreatment with pioglitazone also significantly inhibited the MPTP-induced production of striatal MPP+ and the activity of MAO-B in the striatum. CONCLUSIONS AND IMPLICATIONS: The neuroprotection observed with pioglitazone pretreatment in the MPTP mouse model was due to the blockade of the conversion of MPTP to its active toxic metabolite MPP+, via inhibition of MAO-B.     

Leaf extract of Rhus verniciflua Stokes protects dopaminergic neuronal cells in a rotenone model of Parkinson's disease

Objectives The present study investigated the neuroprotective effects of Rhus verniciflua Stokes (RVS) leaf extract on rotenone‐induced apoptosis in human dopaminergic cells, SH‐SY5Y. Methods Cells were pretreated with RVS extract for 1 h then treated with vehicle or rotenone for 24 h. Cell viability, cell cytotoxicity, cell morphology and nuclear morphology were examined by MTT assay, lactate dehydrogenase release assay, phase contrast microscopy and staining with Hoechast 33342, respectively. Reactive oxygen species were measured by 2′7′‐dichlorofluorescein diacetate and fragmented DNA was observed by TUNEL assay. Mitochondrial membrane potential was determined by Rhodamine 123. Pro‐apoptotic and anti‐apoptotic proteins and tyrosine hydroxylase were analysed by Western blotting. Key findings Results showed that RVS suppressed rotenone‐induced reactive oxygen species generation, cellular injury and apoptotic cell death. RVS also prevented rotenone‐mediated changes in Bax/Bcl‐2 levels, mitochondrial membrane potential dissipation and Caspase 3 activation. Moreover, RVS pretreatment increased the tyrosine hydroxylase levels in SH‐SY5Y cells. Conclusions These findings demonstrate that RVS protects SH‐SY5Y cells against rotenone‐induced injury and suggest that RVS may have potential therapeutic value for neurodegenerative disease associated with oxidative stress.     

Neuroprotection by tetrahydroxystilbene glucoside in the MPTP mouse model of Parkinson's disease

Our in vitro experiments suggested that tetrahydroxystilbene glucoside (TSG) affords a significant neuroprotective effect against MPP⁺-induced damage and apoptosis in PC12 cells though activation of the PI3K/Akt pathway. This study was aimed to investigate the potential neuroprotective effect of TSG in 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine (MPTP)-treated mouse model of Parkinson's disease (PD). We found that treatment of TSG protected dopaminergic neurons by preventing MPTP-induced decreases in substantia nigra tyrosine hydroxylase (TH)-positive cells and striatal dopaminergic transporter (DAT) protein levels. Furthermore, it was also associated with increasing striatal Akt and GSK3β phosphorylation, up-regulation of the Bcl-2/BAD ratio, and inhibition of the activation of caspase-9 and caspase-3. These results showed that TSG promoted dopamine neuron survival in vivo, the PI3K/Akt signaling pathway may have mediated the protection of TSG against MPTP, suggesting that TSG treatment might represent a neuroprotective treatment for PD.     

Adaptive changes in autophagy after UPS impairment in Parkinson's disease

Aim:

Ubiquitin-proteasome system (UPS) and autophagosome-lysosome pathway (ALP) are the most important machineries responsible for protein degradation in Parkinson''s disease (PD). The aim of this study is to investigate the adaptive alterations in autophagy upon proteasome inhibition in dopaminergic neurons in vitro and in vivo.

Methods:

Human dopaminergic neuroblastoma SH-SY5Y cells were treated with the proteasome inhibitor lactacystin (5 μmol/L) for 5, 12, or 24 h. The expression of autophagy-related proteins in the cells was detected with immunoblotting. UPS-impaired mouse model of PD was established by microinjection of lactacystin (2 μg) into the left hemisphere of C57BL/6 mice that were sacrificed 2 or 4 weeks later. The midbrain tissues were dissected to assess alterations in autophagy using immunofluorescence, immunoblotting and electron microscopy assays.

Results:

Both in SH-SY5Y cells and in the midbrain of UPS-impaired mouse model of PD, treatment with lactacystin significantly increased the expression levels of LC3-I/II and Beclin 1, and reduced the levels of p-mTOR, mTOR and p62/SQSTM1. Furthermore, lactacystin treatment in UPS-impaired mouse model of PD caused significant loss of TH-positive neurons in the substantia nigra, and dramatically increased the number of autophagosomes in the left TH-positive neurons.

Conclusion:

Inhibition of UPS by lactacystin in dopaminergic neurons activates another protein degradation system, the ALP, which includes both the mTOR signaling pathway and Beclin 1-associated pathway.     

Animal models of Parkinson's disease: a source of novel treatments and clues to the cause of the disease

Animal models of Parkinson''s disease (PD) have proved highly effective in the discovery of novel treatments for motor symptoms of PD and in the search for clues to the underlying cause of the illness. Models based on specific pathogenic mechanisms may subsequently lead to the development of neuroprotective agents for PD that stop or slow disease progression. The array of available rodent models is large and ranges from acute pharmacological models, such as the reserpine- or haloperidol-treated rats that display one or more parkinsonian signs, to models exhibiting destruction of the dopaminergic nigro-striatal pathway, such as the classical 6-hydroxydopamine (6-OHDA) rat and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse models. All of these have provided test beds in which new molecules for treating the motor symptoms of PD can be assessed. In addition, the emergence of abnormal involuntary movements (AIMs) with repeated treatment of 6-OHDA-lesioned rats with L-DOPA has allowed for examination of the mechanisms responsible for treatment-related dyskinesia in PD, and the detection of molecules able to prevent or reverse their appearance. Other toxin-based models of nigro-striatal tract degeneration include the systemic administration of the pesticides rotenone and paraquat, but whilst providing clues to disease pathogenesis, these are not so commonly used for drug development. The MPTP-treated primate model of PD, which closely mimics the clinical features of PD and in which all currently used anti-parkinsonian medications have been shown to be effective, is undoubtedly the most clinically-relevant of all available models. The MPTP-treated primate develops clear dyskinesia when repeatedly exposed to L-DOPA, and these parkinsonian animals have shown responses to novel dopaminergic agents that are highly predictive of their effect in man. Whether non-dopaminergic drugs show the same degree of predictability of response is a matter of debate. As our understanding of the pathogenesis of PD has improved, so new rodent models produced by agents mimicking these mechanisms, including proteasome inhibitors such as PSI, lactacystin and epoximycin or inflammogens like lipopolysaccharide (LPS) have been developed. A further generation of models aimed at mimicking the genetic causes of PD has also sprung up. Whilst these newer models have provided further clues to the disease pathology, they have so far been less commonly used for drug development. There is little doubt that the availability of experimental animal models of PD has dramatically altered dopaminergic drug treatment of the illness and the prevention and reversal of drug-related side effects that emerge with disease progression and chronic medication. However, so far, we have made little progress in moving into other pharmacological areas for the treatment of PD, and we have not developed models that reflect the progressive nature of the illness and its complexity in terms of the extent of pathology and biochemical change. Only when this occurs are we likely to make progress in developing agents to stop or slow the disease progression. The overarching question that draws all of these models together in the quest for better drug treatments for PD is how well do they recapitulate the human condition and how predictive are they of successful translation of drugs into the clinic? This article aims to clarify the current position and highlight the strengths and weaknesses of available models.

LINKED ARTICLES

This article is part of a themed issue on Translational Neuropharmacology. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2011.164.issue-4     

Population pharmacokinetics of levodopa in subjects with advanced Parkinson's disease: levodopa-carbidopa intestinal gel infusion vs. oral tablets

Aims

Levodopa-carbidopa intestinal gel (LCIG) provides continuous levodopa-carbidopa delivery through intrajejunal infusion. This study characterized the population pharmacokinetics of levodopa following a 16 h jejunal infusion of LCIG or frequent oral administration of levodopa-carbidopa tablets (LC-oral) in subjects with advanced Parkinson''s disease (PD).

Methods

A non-linear mixed-effects model of levodopa pharmacokinetics was developed using serial plasma concentrations from an LCIG phase 1 study and a phase 3 double-blind, double-dummy study of the efficacy and safety of LCIG compared with LC-oral in advanced PD patients (n = 68 for model development; 45 on LCIG and 23 on LC-oral). The final model was internally evaluated using stochastic simulations and bootstrap and externally evaluated using sparse pharmacokinetic data from 311 subjects treated in a long term safety study of LCIG.

Results

The final model was a two compartment model with a transit compartment for absorption, first order elimination, bioavailability for LCIG (97%; confidence interval = 95% to 98%) relative to LC-oral, different first order transit absorption rate constants (LCIG = 9.2 h^–1 vs. LC-oral = 2.4 h^–1; corresponding mean absorption time of 7 min for LCIG vs. 25 min for LC-oral) and different residual (intra-subject) variability for LCIG (15% proportional error, 0.3 μg ml⁻¹ additive error) vs. LC-oral (29% proportional error, 0.59 μg ml⁻¹ additive error). Estimated oral clearance and steady-state volume of distribution for levodopa were 24.8 l h⁻¹ and 131 l, respectively.

Conclusions

LCIG administration results in faster absorption, comparable levodopa bioavailability and significantly reduced intra-subject variability in levodopa concentrations relative to LC-oral administration.     

SIRT3介导褪黑激素保护帕金森病多巴胺能神经元的作用机制

目的研究SIRT3在褪黑激素保护帕金森病(Parkinson’s disease,PD)多巴胺能神经元中的作用。方法48只小鼠随机分为对照组、模型组和治疗组,治疗组小鼠给予褪黑激素(10 mg·kg-1)和MPTP(30 mg·kg-1)腹腔注射,模型组小鼠给予MPTP腹腔注射,对照组小鼠同时给予等量生理盐水,褪黑激素连续给药14 d。采用免疫组化分析黑质TH、Iba-1表达情况,ELISA法检测中脑组织氧化应激指标(ROS、MDA、SOD)及炎症因子(TNF-α、IL-1β)水平,实时定量PCR分析SIRT3 mRNA水平,免疫荧光和Western blot检测蛋白表达情况。结果与对照组比较,模型组小鼠黑质TH表达减少、Iba-1表达增多,中脑组织氧化应激与炎症损伤明显增强,黑质SIRT3 mRNA和蛋白表达水平明显降低,SOD2蛋白表达减少,iNOS蛋白表达增多,组间比较差异均具有统计学意义( P <0.05)。治疗组小鼠经褪黑激素干预后,TH表达增多、Iba-1表达减少,氧化应激与炎症损伤明显减弱,SIRT3 mRNA和蛋白表达水平升高,SOD2蛋白表达上调,iNOS蛋白表达下调,与模型组比较,差异均具有统计学意义( P <0.05)。 结论 褪黑激素通过上调SIRT3表达抵抗PD多巴胺能神经元损伤,作用机制与其抑制小胶质细胞激活减轻氧化应激和炎症损伤有关。     

Suberoylanilide hydroxamic acid, a histone deacetylase inhibitor, protects dopaminergic neurons from neurotoxin-induced damage

BACKGROUND AND PURPOSE

Prevention or disease-modifying therapies are critical for the treatment of neurodegenerative disorders such as Alzheimer''s disease, Parkinson''s disease and Huntington''s disease. However, no such intervention is currently available. Growing evidence has demonstrated that administration of histone deacetylase (HDAC) inhibitors ameliorates a wide range of neurologic and psychiatric disorders in experimental models. Suberoylanilide hydroxamic acid (SAHA) was the first HDAC inhibitor approved by the Food and Drug Administration for the sole use of cancer therapy. The purpose of this study was to explore the potential new indications of SAHA for therapy of neurodegenerative diseases in in vitro Parkinson''s disease models.

EXPERIMENTAL APPROACH

Mesencephalic neuron–glia cultures and reconstituted cultures were used to investigate neurotrophic and neuroprotective effects of SAHA. We measured toxicity in dopaminergic neurons, using dopamine uptake assay and morphological analysis and expression of neurotrophic substances by enzyme-linked immunosorbent assay and real-time RT PCR.

KEY RESULTS

In mesencephalic neuron–glia cultures, SAHA displayed dose- and time-dependent prolongation of the survival and protection against neurotoxin-induced neuronal death of dopaminergic neurons. Mechanistic studies revealed that the neuroprotective effects of SAHA were mediated in part by promoting release of neurotrophic factors from astroglia through inhibition of histone deacetylation.

CONCLUSION AND IMPLICATIONS

The novel neurotrophic and neuroprotective effects of SAHA demonstrated in this study suggest that further study of this HDAC inhibitor could provide a new therapeutic approach to the treatment of neurodegenerative diseases.     

Potential neuroprotective effect of ibuprofen,insights from the mice model of Parkinson's disease

BackgroundParkinson's disease (PD) is one of the most common neurodegenerative diseases. An inflammatory reaction seems to be involved in the pathological process in PD. Prospective clinical studies with various nonsteroidal anti-inflammatory drugs (NSAIDs) have shown that ibuprofen decreases the risk of PD. In the present study we investigated the influence of ibuprofen on dopaminergic neuron injury in the mice model of PD.MethodsTwelve-month-old male C57Bl mice were injected with MPTP together with various doses of ibuprofen (10, 30 or 50 mg/kg), administered 1 h before MPTP injection for 7 consecutive days. Evaluation concerned dopamine content in the striatum, tyrosine hydroxylase (TH) protein and α-synuclein expression measured 7 and 21 days post MPTP administration (dpa).ResultsMPTP caused injury to dopaminergic neuron endings in the striatum: dopamine content decreased by about 90% 7 dpa and by 85% 21 dpa; TH protein expression diminished by 21% 7 dpa; α-synuclein level decreased by 10 and 26% 7 and 21 dpa, respectively. Ibuprofen administration to mice treated with MPTP significantly increased the level of dopamine in the striatum 7 and 21 dpa. It also prevented TH protein decrease and increased α-synuclein level 21 dpa.ConclusionsIbuprofen was shown to protect neurons against MPTP-induced injury in the striatum. The possible mechanism of the neuroprotective effect of ibuprofen might be associated with decreased dopamine turnover and cyclooxygenases inhibition resulting in lower reactive oxygen species formation.     

KW-6002 protects from MPTP induced dopaminergic toxicity in the mouse

The risk of Parkinson's disease (PD) is associated with a lower intake of caffeine, a non-selective adenosine A2A antagonist. In agreement, genetic or pharmacological inactivation of adenosine A2A receptors in animal models of PD has demonstrated both symptomatic and neuroprotective effects. These findings and the lack of disease modifying therapies have led to intense research on adenosine A2A antagonists as a novel treatment for PD. In the present study the neuroprotective effect of the A2A receptor antagonist KW-6002 was investigated using different models of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice, which induced dopaminergic terminal and or dopaminergic cell loss and inflammation. Treatment with KW-6002 prevented the loss of dopaminergic striatal terminals and nigral cell bodies and inhibited the nigral microglia activation. Our results confirm previous findings that pharmacological inactivation of A2A receptors inhibits MPTP-induced dopaminergic damage at the level of striatum. In addition, we demonstrate for the first time that, after MPTP treatment in mice, an A2A antagonist is neuroprotective, and has anti-inflammatory effects, at the level of the substantia nigra. Thus, our data further support the use of A2A receptor antagonists as a novel neuroprotective therapy for PD.     

Safinamide for the treatment of Parkinson's disease

Vasopressin (AVP) and oxytocin (OT) are cyclic nonapeptides whose actions are mediated by the stimulation of specific G-protein-coupled receptors (GPCRs) currently classified into V₁-vascular (V₁R), V₂-renal (V₂R) and V₃-pituitary (V₃R) AVP receptors and OT receptors (OTR). The signal transduction pathways coupled to the different subtypes of AVP/OT receptors are reviewed. The recent cloning of the different members of the AVP/OT family of receptors now allows the extensive characterisation of the molecular determinants involved in agonist and antagonist binding, as well as signal transduction coupling. Potential therapeutic uses of AVP receptor antagonists include: the blockade of V₁-vascular AVP receptors in arterial hypertension, congestive heart failure (CHF) and peripheral vascular diseases; the blockade of V₂-renal AVP receptors in the syndrome of inappropriate vasopressin secretion, CHF, liver cirrhosis, nephrotic syndrome and any state of excessive retention of free water and subsequent hyponatraemia; the blockade of V₃-pituitary AVP receptors in adrenocorticotropin (ACTH)-secreting tumours. The pharmacological and clinical profile of orally-active non-peptide AVP receptor antagonists is reviewed.     

Recent Progress of Imaging Agents for Parkinson's Disease

Parkinson''s disease (PD) is a common progressive, neurodegenerative brain disease that is promoted by mitochondrial dysfunction, oxidative stress, protein aggregation and proteasome dysfunction in the brain. Compared with computer tomography (CT) or magnetic resonance imaging (MRI), non-invasive nuclear radiopharmaceuticals have great significance for the early diagnosis of PD due to their high sensitivity and specificity in atypical and preclinical cases. Based on the development of coordination chemistry and chelator design, radionuclides may be delivered to lesions by attaching to PD-related transporters and receptors, such as dopamine, serotonin, and others. In this review, we comprehensively detailed the current achievements in radionuclide imaging in Parkinson’s disease.     

FSD-C10抑制MPTP诱导的帕金森病小鼠氧化应激及炎性反应研究

目的 研究口服FSD-C10对帕金森病（Parkinson's disease,PD）小鼠的治疗作用,并探讨其相关机制。方法 小鼠随机分为正常组、PD组和FSD-C10组（50 mg·kg^-1）,旷场行为学测试评估小鼠移动的总距离、休息时间、穿格次数;Western blotting检测脑组织酪氨酸羟化酶（tyrosine hydroxylase,TH）、ROCKⅡ;比色法检测脑组织过氧化氢酶（catalase,CAT）、还原型谷胱甘肽（glutathione,GSH）、丙二醛和一氧化氮（nitric oxide,NO）;ELISA检测脑组织肿瘤坏死因子（tumor necrosis factor-α,TNF-α）、白介素-1β（interleukin-1β,IL-1β）及白介素-6（interleukin-6,IL-6）。结果 与正常组比较,PD组小鼠移动的总距离、穿格次数降低（P<0.01）,休息时间延长（P<0.01）,TH表达降低（P<0.05）,ROCKⅡ表达增高（P<0.05）,CAT活力下降（P<0.05）,GSH含量降低（P<0.01）,丙二醛含量升高（P<0.05）,TNF-α、IL-1β、IL-6及NO升高（P<0.05或P<0.01）。与PD组比较,FSD-C10组小鼠移动的总距离、穿格次数增加（P<0.05）,休息时间缩短（P<0.01）,TH表达增高（P<0.05）,ROCKⅡ表达降低（P<0.05）,CAT活力增加（P<0.01）,GSH含量升高（P<0.01）,丙二醛含量降低（P<0.01）,TNF-α、IL-1β、IL-6及NO下降（P<0.01）。结论 口服FSD-C10可以改善PD小鼠的行为学表现,对PD有明确的治疗作用,其作用机制可能与恢复氧化-抗氧化体系平衡、减少炎性因子分泌相关。     

Symptomatic and neuroprotective effects following activation of nigral group III metabotropic glutamate receptors in rodent models of Parkinson's disease

Background and purpose:

Increased glutamatergic innervation of the substantia nigra pars reticulata (SNpr) and pars compacta (SNpc) may contribute to the motor deficits and neurodegeneration, respectively, in Parkinson''s disease (PD). This study aimed to establish whether activation of pre-synaptic group III metabotropic glutamate (mGlu) receptors reduced glutamate release in the SN, and provided symptomatic or neuroprotective relief in animal models of PD.

Experimental approach:

Broad-spectrum group III mGlu receptor agonists, O-phospho-l-serine (l-SOP) and l-2-amino-4-phosphonobutyrate (l-AP4), were assessed for their ability to inhibit KCl-evoked [³H]-d-aspartate release in rat nigral prisms or inhibit KCl-evoked endogenous glutamate release in the SNpr in vivo using microdialysis. Reversal of akinesia in reserpine-treated rats was assessed following intranigral injection of l-SOP and l-AP4. Finally, the neuroprotective effect of 7 days'' supra-nigral treatment with l-AP4 was examined in 6-hydroxydopamine (6-OHDA)-lesioned rats.

Key results:

l-SOP and l-AP4 inhibited [³H]-d-aspartate release by 33 and 44% respectively. These effects were blocked by the selective group III mGlu antagonist (RS)-α-cyclopropyl-4-phosphonophenylglycine (CPPG). l-SOP also reduced glutamate release in the SNpr in vivo by 48%. Injection of l-SOP and l-AP4 into the SNpr reversed reserpine-induced akinesia. Following administration above the SNpc, l-AP4 provided neurochemical, histological and functional protection against 6-OHDA lesion of the nigrostriatal tract. Pretreatment with CPPG inhibited these effects.

Conclusions and implications:

These findings highlight group III mGlu receptors in the SN as potential targets for providing both symptomatic and neuroprotective relief in PD, and indicate that inhibition of glutamate release in the SN may underlie these effects.     

The influence of AAV2-mediated gene transfer of human IL-10 on neurodegeneration and immune response in a murine model of Parkinson's disease

BackgroundThe aim of this study was to examine the effect of AAV2-hIL-10 (vector containing cDNA for human interleukin 10) on dopaminergic system activity (measured as DA levels and TH mRNA expression in mouse striata), and other monoamine and amino acid neurotransmitters concentration as well as development of inflammatory processes (measured as TGF-β, IFN-γ and GFAP mRNA expression) in a murine MPTP neurotoxicant model of Parkinson's disease.MethodsMale C57BL/6 mice 12 months-old were used in this study. AAV2-hIL-10 vector was bilaterally administered into striatum at 14, 21 or 28 days prior to MPTP intoxication. Animals were sacrificed at 7 days following MPTP injection. The expression of hIL-10 (human interleukin 10) was examined by ELISA. Striatal monoamine and amino acid neurotransmitters were measured by HPLC method. TH, TGF-β, IFN-γ and GFAP mRNA expression was examined by RT-PCR method.ResultsMPTP treatment dramatically reduced DA levels and decreased TH mRNA expression in mouse striata, effects that were significantly impeded by AAV2-hIL-10 administration prior to MPTP intoxication. AAV2-hIL-10 infusion increased IFN-γ, TGF-β and GFAP mRNA expression.ConclusionsOur data suggest that the transfer of AAV2-hIL-10 into the striatum may play a neuroprotective role in the mouse MPTP model of PD and these effects are mediated by the anti-inflammatory action of IL-10.     

JMJD3在帕金森病中的研究进展

帕金森病(PD)是一种中老年人常见的神经退行性疾病,其致病因素尚不明确。遗传、饮食习惯、环境毒素、免疫学异常、炎症、氧化应激反应、线粒体功能缺陷、细胞凋亡等所引起的各种生理生化的改变都有可能加剧PD的发生。近年来,有研究表明,小胶质细胞的活化与PD密切相关,活化的小胶质细胞能够促进炎性因子的释放;同时,中脑黑质区多巴胺能神经元的分化情况也与PD有着紧密联系。而作为组蛋白H3K27me3去甲基化酶,JMJD3参与并影响着小胶质细胞的活化,同时能够调控小胶质细胞的极化状态,并影响中脑内多巴胺能神经元的存亡。这为治疗PD提供了新的方法与策略。该文就JMJD3的结构、功能,以及其在小胶质细胞介导的神经炎症中的作用和对神经元的影响展开综述,探究JMJD3在PD中的作用及相关研究进展。