The phosphorylation state of Ser-129 in human alpha-synuclein determines neurodegeneration in a rat model of Parkinson disease

Studies have shown that alpha-synuclein (alpha-syn) deposited in Lewy bodies in brain tissue from patients with Parkinson disease (PD) is extensively phosphorylated at Ser-129. We used recombinant Adeno-associated virus (rAAV) to overexpress human wild-type (wt) alpha-syn and two human alpha-syn mutants with site-directed replacement of Ser-129 to alanine (S129A) or to aspartate (S129D) in the nigrostriatal tract of the rat to investigate the effect of Ser-129 phosphorylation state on dopaminergic neuron pathology. Rats were injected with rAAV2/5 vectors in the substantia nigra pars compacta (SNc) on one side of the brain; the other side remained as a nontransduced control. The level of human wt or mutant alpha-syn expressed on the injected side was about four times the endogenous rat alpha-syn. There was a significant reduction of dopaminergic neurons in the SNc and dopamine (DA) and tyrosine hydroxylase (TH) levels in the striatum of all S129A-treated rats as early as 4 wk postinjection. Nigral DA pathology occurred more slowly in the wt-injected animals, but by 26 wk the wt alpha-syn group lost nigral TH neurons equivalent to the mutated S129A group at 8 wk. In stark contrast, we did not observe any pathological changes in S129D-treated animals. Therefore, the nonphosphorylated form of S129 exacerbates alpha-syn-induced nigral pathology, whereas Ser-129 phosphorylation eliminates alpha-syn-induced nigrostriatal degeneration. This suggests possible new therapeutic targets for Parkinson Disease.     

Minocycline prevents nigrostriatal dopaminergic neurodegeneration in the MPTP model of Parkinson's disease

Parkinson's disease is a chronic neurodegenerative disorder characterized by the loss of dopamine neurons in the substantia nigra, decreased striatal dopamine levels, and consequent extrapyramidal motor dysfunction. We now report that minocycline, a semisynthetic tetracycline, recently shown to have neuroprotective effects in animal models of stroke/ischemic injury and Huntington's disease, prevents nigrostriatal dopaminergic neurodegeneration in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson's disease. Minocycline treatment also blocked dopamine depletion in the striatum as well as in the nucleus accumbens after MPTP administration. The neuroprotective effect of minocycline is associated with marked reductions in inducible NO synthase (iNOS) and caspase 1 expression. In vitro studies using primary cultures of mesencephalic and cerebellar granule neurons (CGN) and/or glia demonstrate that minocycline inhibits both 1-methyl-4-phenylpyridinium (MPP(+))-mediated iNOS expression and NO-induced neurotoxicity, but MPP(+)-induced neurotoxicity is inhibited only in the presence of glia. Further, minocycline also inhibits NO-induced phosphorylation of p38 mitogen-activated protein kinase (MAPK) in CGN and the p38 MAPK inhibitor, SB203580, blocks NO toxicity of CGN. Our results suggest that minocycline blocks MPTP neurotoxicity in vivo by indirectly inhibiting MPTP/MPP(+)-induced glial iNOS expression and/or directly inhibiting NO-induced neurotoxicity, most likely by inhibiting the phosphorylation of p38 MAPK. Thus, NO appears to play an important role in MPTP neurotoxicity. Neuroprotective tetracyclines may be effective in preventing or slowing the progression of Parkinson's and other neurodegenerative diseases.     

Lentiviral gene transfer ameliorates disease progression in Long-Evans cinnamon rats: An animal model for Wilson disease

Objective. Wilson disease is a copper storage disorder caused by mutations in the ATP7B gene leading to liver cirrhosis. It has previously been shown that lentiviral vectors can govern an efficient delivery and stable expression of a transgene. The aim of this pilot study was to prove the principle of a lentiviral gene transfer in the Long-Evans cinnamon (LEC) rat, an animal model of Wilson disease. Material and methods. LEC rats were treated either by systemic application of lentiviral vectors or by intrasplenic transplantation of LEC-rat hepatocytes lentivirally transduced with ATP7B. The ATP7B gene expression was analyzed by RT-PCR and immunofluorescence analysis. The therapeutic effect was assessed by analysis of liver histology, serum ceruloplasmin oxidase activity, and liver copper content. Results, Hepatic expression of the transgene was detected at different time-points post-treatment and lasted for up to 24 weeks (end of experiment). Liver copper levels were lowered in all treatment groups compared to untreated LEC rats. Twenty-four weeks after treatment, the area of the examined liver-tissue sections occupied by fibrosis was 48.3–57.9% in untreated LEC rats and 10.7–19.8% in rats treated with cell therapy. In systemically treated rats, only small fibrous septa could be observed. Conclusions. These data prove for the first time that lentiviral ATP7B gene transfer is feasible in Wilson disease. In our pilot study the systemic approach was more promising in ameliorating disease progression than the transplantation of lentivirally transduced hepatocytes.     

尿酸对帕金森病模型大鼠多巴胺能神经元氧化应激的影响

目的 探讨尿酸对6-羟多巴胺(6-OHDA)诱导的SD大鼠帕金森病体外模型多巴胺(DA)能神经元氧化应激损伤的影响. 方法取孕12～14 d SD大鼠中脑原代细胞进行培养.实验分3组:(1)对照组:原代培养细胞;(2)6-OHDA组:原代培养细胞加6-OHDA;(3)尿酸组:不同浓度尿酸(5、50、100、250、500 μmol/L)分为5个亚组.培养第5天开始加尿酸干预,持续作用5 d,于第10天加50μmol/L的6-OHDA,作用2 h,培养第10天收集细胞.经酪氨酸羟化酶(TH)免疫细胞化学染色,3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)法检测细胞活力;通过流式细胞仪,用罗丹明123(Rh123)检测线粒体膜电位(△ψm). 结果对照组TH阳性(TH~+)细胞[(296.8±42.5)个/ml]较多,突起较长,部分密集成网状;6-OHDA组TH~+细胞[(92.8±19.7)个/ml]明显减少,突起较短,部分有断裂;5、50、100、250、500 μmol/L尿酸组TH~+细胞数(96.5±20.1、115.5± 30.0、152.5±26.7、205.0±48.2、230.1±22.5)个/ml,较对照组减少,但明显多于6-OHDA组,并且同尿酸浓度成正相关(F=13.94,P<0.05).与对照组比较,6-OHDA组细胞活力明显下降(F=90.19,P<0.05);5、50、100、500μmol/L尿酸组细胞活力较对照组下降(F=14.56,P<0.05),但高于6-OHDA组(F=40.96,P<0.05).250 μmol/L尿酸组细胞活力与对照组比较,差异无统计学意义(F=1.27,P>0.05).对照组△ψm(30.05±5.88)%,与6-OHDA组(23.67±2.72)比较明显下降(F=6.30,P<0.05);而尿酸各组与6-OHDA组比较,均升高;其中100、250μmol/L尿酸组△ψm(36.91±2.44)%、(38.08±2.90)%高于对照组(F=4.62,P<0.05). 结论尿酸可减少6-OHDA对神经元的毒性作用,提高细胞活力,稳定细胞膜电位,表明尿酸能通过抗氧化应激活性发挥其对多巴胺能神经元的保护作用.     

Selective inhibition of NF-kappaB activation prevents dopaminergic neuronal loss in a mouse model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disorder. Despite intense investigations, no effective therapy is available to stop its onset or halt its progression. The present study evaluates the ability of peptide corresponding to the NF-κB essential modifier-binding domain (NBD) of IκB kinase α (IKKα) or IKKβ to prevent nigrostriatal degeneration in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD and establish a role for NF-κB in human parkinsonism. First, we found that NF-κB was activated within the substantia nigra pars compacta of PD patients and MPTP-intoxicated mice. However, i.p. injection of wild-type NBD peptide reduced nigral activation of NF-κB, suppressed nigral microglial activation, protected both the nigrostriatal axis and neurotransmitters, and improved motor functions in MPTP-intoxicated mice. These findings were specific because mutated NBD peptide had no effect. We conclude that selective inhibition of NF-κB activation by NBD peptide may be of therapeutic benefit for PD patients.     

Bax ablation prevents dopaminergic neurodegeneration in the 1-methyl- 4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) damages dopaminergic neurons in the substantia nigra pars compacta (SNpc) as seen in Parkinson's disease. Here, we show that the pro-apoptotic protein Bax is highly expressed in the SNpc and that its ablation attenuates SNpc developmental neuronal apoptosis. In adult mice, there is an up-regulation of Bax in the SNpc after MPTP administration and a decrease in Bcl-2. These changes parallel MPTP-induced dopaminergic neurodegeneration. We also show that mutant mice lacking Bax are significantly more resistant to MPTP than their wild-type littermates. This study demonstrates that Bax plays a critical role in the MPTP neurotoxic process and suggests that targeting Bax may provide protective benefit in the treatment of Parkinson's disease.     

alpha -Synucleinopathy and selective dopaminergic neuron loss in a rat lentiviral-based model of Parkinson's disease

Parkinson's disease (PD) is characterized by the progressive loss of substantia nigra dopaminergic neurons and the presence of cytoplasmic inclusions named Lewy bodies. Two missense mutations of the alpha-synuclein (alpha-syn; A30P and A53T) have been described in several families with an autosomal dominant form of PD. alpha-Syn also constitutes one of the main components of Lewy bodies in sporadic cases of PD. To develop an animal model of PD, lentiviral vectors expressing different human or rat forms of alpha-syn were injected into the substantia nigra of rats. In contrast to transgenic mice models, a selective loss of nigral dopaminergic neurons associated with a dopaminergic denervation of the striatum was observed in animals expressing either wild-type or mutant forms of human alpha-syn. This neuronal degeneration correlates with the appearance of abundant alpha-syn-positive inclusions and extensive neuritic pathology detected with both alpha-syn and silver staining. Lentiviral-mediated expression of wild-type or mutated forms of human alpha-syn recapitulates the essential neuropathological features of PD. Rat alpha-syn similarly leads to protein aggregation but without cell loss, suggesting that inclusions are not the primary cause of cell degeneration in PD. Viral-mediated genetic models may contribute to elucidate the mechanism of alpha-syn-induced cell death and allow the screening of candidate therapeutic molecules.     

Gene delivery of human apolipoprotein E alters brain Abeta burden in a mouse model of Alzheimer's disease

Apolipoprotein E (apoE) alleles are important genetic risk factors for Alzheimer's disease (AD), with the epsilon4 allele increasing and the epsilon2 allele decreasing risk for developing AD. ApoE has been shown to influence brain amyloid-beta peptide (Abeta) and amyloid burden, both in humans and in transgenic mice. Here we show that direct intracerebral administration of lentiviral vectors expressing the three common human apoE isoforms differentially alters hippocampal Abeta and amyloid burden in the PDAPP mouse model of AD. Expression of apoE4 in the absence of mouse apoE increases hippocampal Abeta(1-42) levels and amyloid burden. By contrast, expression of apoE2, even in the presence of mouse apoE, markedly reduces hippocampal Abeta burden. Our data demonstrate rapid apoE isoform-dependent effects on brain Abeta burden in a mouse model of AD. Gene delivery of apoE2 may prevent or reduce brain Abeta burden and the subsequent development of neuritic plaques.     

蛋白激酶C抑制剂改善帕金森病大鼠异动症的研究

目的 探讨蛋白激酶C(PKC)抑制剂他莫昔芬对左旋多巴诱发异动症的细胞学与行为学效应. 方法将6-羟多巴胺立体定向注射于大鼠前脑内侧束建立帕金森病(PD)动物模型.模型成功的PD大鼠接受每天2次左旋多巴(50 mg/kg左旋多巴+12.5 mg/kg苄丝肼)腹腔注射,持续22 d.在第23天左旋多巴注射前,2组PD大鼠给予他莫昔芬或溶剂处理.评估旋转反应时间及剂峰旋转次数,采用蛋白印迹法检测纹状体区N-甲基-D-天冬氨酸受体NR1亚单位(NR1)和890、896位丝氨酸位点磷酸化的NR1(NR1S890、NR1S896)表达情况. 结果 PKC抑制剂他莫昔芬减轻少了左旋多巴诱导的PD大鼠剂峰旋转次数[(121.0±7.6)次与(161.5±22.1)次,t=2.6,P<0.05];此外,他莫昔芬能调节与异动症密切相关的NR1的亚细胞分布,使纹状体部位NR1在膜蛋白中的表达量减少至(82.4±5.1)%,与左旋多巴+溶剂组[(103.0±3.5)%]比较差异有统计学意义(t=6.7,P<0.05),同时使NR1S890、NR1S896的磷酸化水平明显降低,其表达量分别为(77.2±4.2)%与(98.4±6.4)%(t=5.9、3.6,均P<0.05). 结论长期左旋多巴作用激活了纹状体棘状神经元内丝氨酸激酶PKC,并导致谷氨酸受体磷酸化,从而出现了异动症;抑制丝氨酸激酶(如PKC)活性的药物可能是治疗及预防帕金森病异动症的一种新的治疗方式.     

不同中医治法对帕金森病大鼠氧化应激反应的影响

目的研究不同中医治法对帕金森病大鼠氧化应激反应的影响。方法采用经典的6-羟基多巴胺损毁注射法制作PD模型,并应用活血化瘀（代表方桃红四物汤）、涤痰熄风（代表方涤痰汤）、滋阴熄风（代表方天麻钩藤饮）和复合治法（代表方复方地黄方）等不同治法的方剂进行治疗,同时设立正常对照组、假手术组作对照。测定大鼠中脑黑质纹状体部位丙二醛、谷胱甘肽含量,谷胱甘肽过氧化物酶、超氧化物歧化酶的活性。结果模型组SOD、GSH、GSH—Px下降,MDA升高。各中药组均可以改善模型组的异常变化,差异均有统计学意义（P〈0．05,或P〈0．01）。桃红四物汤组与涤痰汤组比较,各指标差异均无统计学意义（P〈0．05）。天麻钩藤饮组与桃红四物汤组比较,在SOD、MDA、GSH指标上差异均有统计学意义（P〈0．05,或P〈0．01）;与涤痰汤组比较,在SOD、MDA指标上差异均有统计学意义（p〈0．05）。复方地黄方与桃红四物汤比较,在SOD、MDA和GSH—Px指标上差异均有统计学意义（P〈0．05,或P〈0．01）;与涤痰汤比较,在SOD、MDA和GSH指标上,差异均有统计学意义（P〈0．01）;与天麻钩藤饮比较,在GSH指标上,差异有统计学意义（P〈0．01）。结论各种治法均有明显的抗氧化应激损伤的作用,但以复合治法为好。     

基因治疗帕金森病大鼠脑内纹状体多巴胺含量的检测

目的观察脑源性神经营养因子（ＢＤＮＦ）基因工程成肌细胞脑内纹状体移植对帕金森病（ＰＤ）大鼠脑内纹状体多巴胺含量的影响。方法建立逆转录病毒介导的ＢＤＮＦ表达质粒,并转染成肌细胞进行ＰＤ大鼠脑内纹状体移植。结果细胞移植后第２和第８周,移植组毁损侧纹状体多巴胺含量〔分别为（９５７５３±８８９５）和（１０４０２９±１０４７８）ｐｇ／ｍｇ〕较对照组〔分别为（３３５９８±１０２４８）和（３２７８８±７０２３）ｐｇ／ｍｇ〕明显增加（均为Ｐ＜００１）,并可维持２个月之久。结论脑源性神经营养因子基因工程成肌细胞脑内纹状体移植,可使脑内纹状体多巴胺含量明显增加,可能为帕金森病的治疗提供了一种新的治疗方法。     

Increased glutathione S-transferase activity rescues dopaminergic neuron loss in a Drosophila model of Parkinson's disease

Loss-of-function mutations of the parkin gene are a major cause of early-onset parkinsonism. To explore the mechanism by which loss of parkin function results in neurodegeneration, we are using a genetic approach in Drosophila. Here, we show that Drosophila parkin mutants display degeneration of a subset of dopaminergic (DA) neurons in the brain. The neurodegenerative phenotype of parkin mutants is enhanced by loss-of-function mutations of the glutathione S-transferase S1 (GstS1) gene, which were identified in an unbiased genetic screen for genes that modify parkin phenotypes. Furthermore, overexpression of GstS1 in DA neurons suppresses neurodegeneration in parkin mutants. Given the previous evidence for altered glutathione metabolism and oxidative stress in sporadic Parkinson's disease (PD), these data suggest that the mechanism of DA neuron loss in Drosophila parkin mutants is similar to the mechanisms underlying sporadic PD. Moreover, these findings identify a potential therapeutic approach in treating PD.     

Neural stem cell transplantation and melatonin treatment in a 6-hydroxydopamine model of Parkinson's disease

Melatonin has multiple roles including neuroprotection. Melatonin signaling involves diverse targets including two G-protein-coupled receptors, MT(1) and MT(2), which have both been localized to the nigrostriatal pathway. Previous studies in our laboratory demonstrated preservation of tyrosine hydroxylase immunoreactivity, following chronic treatment with a physiological dose of melatonin, in the 6-hydroxydopamine rat model of Parkinson's disease. Additionally, we reported the presence of the melatonin MT(1) receptor subtype in cultured C17.2 neural stem cells (NSCs). In the present study, we examined the effects of C17.2 NSC transplantation on dopaminergic denervation following 6-hydroxydopamine lesioning in the rat striatum. Moreover, based on our detection of the MT(1) in these cells, we examined the effects of combined C17.2 NSC transplantation and melatonin treatment, following striatal lesioning. Behavioral studies indicated a marked inhibition of apomorphine-induced rotations in lesioned animals that received C17.2 NSC transplantation, melatonin, or the combined regimen. In addition, these treatments resulted in a significant protection of tyrosine hydroxylase immunoreactivity in the striatum and substantia nigra of lesioned animals, when compared with untreated controls. Lesioned animals treated with C17.2 NSCs, melatonin or a combination of both agents exhibited no significant differences in the number of tyrosine hydroxylase-positive cells in the substantia nigra or ventral tegmental area ipsilateral or contralateral to the lesioned striatum. These findings suggest that stem cell therapy and concomitant use of neuroprotective agents such as melatonin could be a viable approach in Parkinson's disease.     

99mTc-TRODAT-1放射自显影对帕金森病大鼠模型多巴胺转运蛋白的观察

目的　探讨 99m Tc- TRODAT- 1多巴胺转运蛋白 (DAT)显像临床应用价值。　方法　应用 6 -羟基多巴胺 (6 - OHDA)建立完全损毁及部分损毁一侧帕金森病 (PD)大鼠模型 ,以 99m Tc-TRODAT- 1作为配体 ,采用放射自显影观察一侧 PD大鼠模型 DAT分布及其密度 ,高效液相 -电化学方法检测模型大鼠纹状体多巴胺 (DA)及其代谢产物含量 ,免疫组化酪氨酸羟化酶 (TH)染色观察模型大鼠黑质及纹状体 TH阳性细胞及纤维。　结果　 6 - OHDA损毁侧纹状体放射性浓集明显低于未损毁侧 ,完全损毁模型的纹状体放射性浓集最低。纹状体 DA含量部分损毁及完全损毁较未损毁侧分别降低 39%和 98%。TH染色可见损毁侧黑质及纹状体 TH阳性细胞及纤维明显少于对侧。　结论　 PD大鼠模型损毁侧纹状体 DAT密度降低 ,且与损毁程度有关。99m Tc- TRODAT- 1DAT显像研究可能有助于 PD的早期诊断。     

Autoantibodies and an immune-based rat model of inflammatory bowel disease

The exact causes of inflammatory bowel disease(IBD)are not yet fully defined.From a vast body of literature,we know that the immune response has long been involved in the pathogenesis of IBD,including both ulcerative colitis and Crohn’s disease.A variety of specific alterations can lead to immune activation and inflammation directed to the colon,as revealed by some animal models.Current research has focused on the role of antibodies in downstream events and mechanisms of autoimmunity and inflammation.It is not well known whether the production of antibodies is a serologic consequence of IBD,or if it is a result of barrier dysfunction induced by inflammation.Here,we present a new hypothesis to distinguish the complex links between genetic susceptibility,barrier dysfunction,commensal and pathologic microbial factors and inflammatory response(especially autoantibodies)in the pathogenesis of IBD.To ascertain the hypothesis,we developed a pilot model with the concept of the presence of antibodies against enteric bacterial antigens in IBD.Results confirmed our hypothesis.Our hypothesis suggests the possibility of subcutaneous vaccination of animals with administration of all or specific enteric bacterial antigens.     

Benznidazole prevents endothelial damage in an experimental model of Chagas disease

ObjectivesTo evaluate the effect of benznidazole on endothelial activation in a murine model of Chagas disease.MethodsA low (30 mg/kg/day) and a high (100 mg/kg/day) dose of benznidazole were administered to mice infected with Trypanosoma cruzi during the early phases of the infection. The effects of the treatments were assessed at 24 and 90 days postinfection by evaluating the parasitaemia, mortality, histopathological changes and expression of ICAM in the cardiac tissue. The blood levels of thromboxane A₂, soluble ICAM and E-selectin were also measured. T. cruzi clearance was assessed by the detection of parasite DNA in the heart tissue of infected mice.ResultsBenznidazole decreased the cardiac damage induced by the parasite, and amastigote nests disappeared at 90 days postinfection. Both doses cleared the parasite from the cardiac tissue at 24 and 90 days postinfection. In addition, benznidazole decreased the thromboxane levels and normalized the plasma sICAM and sE-selectin levels by 90 days postinfection.ConclusionsEarly administration of benznidazole at a dose as low as 30 mg/kg eradicates T. cruzi from cardiac tissue. Additionally, benznidazole prevents cardiac damage and modulates endothelial activation as part of its antichagasic activity.     

FGF2 gene transfer restores hippocampal functions in mouse models of Alzheimer's disease and has therapeutic implications for neurocognitive disorders

The adult hippocampus plays a central role in memory formation, synaptic plasticity, and neurogenesis. The subgranular zone of the dentate gyrus contains neural progenitor cells with self-renewal and multilineage potency. Transgene expression of familial Alzheimer's disease-linked mutants of β-amyloid precursor protein (APP) and presenilin-1 leads to a significant inhibition of neurogenesis, which is potentially linked to age-dependent memory loss. To investigate the effect of neurogenesis on cognitive function in a relevant disease model, FGF2 gene is delivered bilaterally to the hippocampi of APP+presenilin-1 bigenic mice via an adenoassociated virus serotype 2/1 hybrid (AAV2/1-FGF2). Animals injected with AAV2/1-FGF2 at a pre- or postsymptomatic stage show significantly improved spatial learning in the radial arm water maze test. A neuropathological investigation demonstrates that AAV2/1-FGF2 injection enhances the number of doublecortin, BrdU/NeuN, and c-fos-positive cells in the dentate gyrus, and the clearance of fibrillar amyloid-β peptide (Aβ) in the hippocampus. AAV2/1-FGF2 injection also enhances long-term potentiation in another APP mouse model (J20) compared with control AAV2/1-GFP-injected littermates. An in vitro study confirmed the enhanced neurogenesis of mouse neural stem cells by direct AAV2/1-FGF2 infection in an Aβ oligomer-sensitive manner. Further, FGF2 enhances Aβ phagocytosis in primary cultured microglia, and reduces Aβ production from primary cultured neurons after AAV2/1-FGF2 infection. Thus, our data indicate that virus-mediated FGF2 gene delivery has potential as an alternative therapy of Alzheimer's disease and possibly other neurocognitive disorders.