Suppression of Calbindin-D28k Expression Exacerbates SCA1 Phenotype in a Disease Mouse Model

Spinocerebellar ataxia type?1 (SCA1) is an autosomal dominant neurological disorder caused by the expansion of a polyglutamine tract in the mutant protein ataxin-1. The cerebellar Purkinje cells (PCs) are the major targets of mutant ataxin-1. The mechanism of PC death in SCA1 is not known; however, previous work indicates that downregulation of specific proteins involved in calcium homeostasis and signaling by mutant ataxin-1 is the probable cause of PC degeneration in SCA1. In this study, we explored if targeted deprivation of PC specific calcium-binding protein calbindin-D28k (CaB) exacerbates ataxin-1 mediated toxicity in SCA1 transgenic (Tg) mice. Using behavioral tests, we found that though both SCA1/+ and SCA1/+: CaB null (-/+) double mutants exhibited progressive impaired performance on the rotating rod, a simultaneous enhancement of exploratory activity, and absence of deficits in coordination, the double mutants were more severely impaired than SCA1/+ mice. With increasing age, SCA1/+ mice showed a progressive loss in the expression and localization of CaB and other PC specific calcium-binding and signaling proteins. In double mutants, these changes were more pronounced and had an earlier onset. Gene expression profiling of young mice exhibiting no behavior or biochemical deficits revealed a differential expression of many genes common to SCA1/+ and CaB-/+ lines, and unique to SCA1/+: CaB-/+ phenotype. Our study provides further evidence for a critical role of CaB in SCA1 pathogenesis, which may help identify new therapeutic targets to treat SCA1 or other cerebellar ataxias.     

A Mouse Model of Alzheimer's Disease with Transplanted Stem-Cell-Derived Human Neurons

正Alzheimer’s disease(AD),the main cause of dementia,is defined by the combined presence of amyloid-b(Ab)deposition and abnormal tau aggregation[1].Experimental models are critical to obtain a better understanding of AD pathogenesis,and to evaluate the potential of novel therapeutic approaches.The most commonly used AD     

Ganglioside GM1 overcomes serum inhibition of neuritic outgrowth

Considerable variations in both neuritic and non-neuronal cell outgrowths of ganglionic expiant cultures are imposed when different substrata and medium supplements are used. Therefore, a neuritic response to exogenous agents such as gangliosides may be better, or exclusively revealed under selected combinations of medium and substratum. We have surveyed a number of different ganglia for their ability to display a neuritic response to ganglioside GM1 and the culture conditions under which such a display may take place. GM1 can recognizably promote neurite extension from embryonic day 8 chick dorsal root ganglia, day 11 sympathetic ganglia, and day 8 ciliary ganglia. Demonstration of such effects, however, requires an appropriate balance between promoting and inhibiting influences by other extrinsic influences (culture substrata, neuronotrophic factors, serum inhibitors) thereby allowing for improvement by the ganglioside. Different ganglia require different combinations of those influences. Ciliary ganglia, for example, will show a GM1 response on a polyornithine substratum in medium supplemented with the chick eye Ciliary Neuronotrophic Factor and 1% fetal calf serum, but not with 10% serum or no serum. The effective concentration range for GM1 is in accord with previously reported serum binding data. These, and other data are consistent with an action of GM1 in executing a neurite program, rather than an imposition of the program itself.     

Ganglioside GM1 elevation in DBA/2 mouse embryos

The composition of whole embryo gangliosides at embryonic day E-12 was compared among the C57BL/6 (B6) DBA/2 (D2), and C3H mouse strains. N-acetylneuraminic acid was the predominant sialic acid species in the E-12 embryos. N-glycolyneuraminic acid was either undetectable or present in only trace amounts. Whole embryo ganglioside sialic concentration was significantly lower in D2 embryos than in B6 or C3H embryos. GM3 and GD3 were the most abundant ganglioside species in each strain and comprised approximately 75% of the total distribution. The D2 embryos expressed an elevation of GD1a and a reduction of GQ1b relative to B6 and C3H. Also, the level of GM1 was significantly higher in the D2 embryos than in the B6 or C3H embryos. Since a reduction of beta-galactosidase activity and an elevation of GM1 concentration in brain were previously reported in postnatal DBA mice, our results suggest that the elevated GM1 in D2 embryos may result from a reduced activity of GM1 beta-galactosidase.     

Ganglioside GM1 and GM3 in early human brain development: An immunocytochemical study

The distribution of GM1 and GM3 gangliosides in human brain development between gestational week (g.w.) 6 and 15 was demonstrated by an immunocytochemical approach using polyclonal anti-GM1 and anti-GM3 antibodies. The first appearance of GM1- and GM3-positive cells was recorded as early as in g.w. 6. Both antibodies labeled the cells in the ventricular zone of the telencephalic wall, with radially oriented fibers toward the pial surface, which represent radial glia cells with glia fibers. The intensive GM3 immunoreactivity was also exhibited in proliferating cells in the ventricular zone between g.w. 6 and 12. During the period from g.w. 12 to 15, characterized by a rapid multiplication of neurons and glia cells, an increased number of GM1- and GM3-positive cells was observed. Prominent GM1 ganglioside staining was observed at the surface of the cell bodies in the ventricular zone. Besides surface labeling in migrating cells, GM1 immunoreactivity was identified inside the soma in the regions of cortical plate and subplate. GM1 immunoreactivity was more pronounced on the membrane of neuronal cells migrating along radial glia fibers, especially at the contact site between neuronal and glial cells. The GM3 ganglioside was localized mostly inside the soma, showing a granular immunoreactivity pattern.Our observations confirm the presence of GM1 and GM3 gangliosides in neuronal and glial cells in early human brain development. The involvement, especially of GM1 ganglioside in glia-neuronal contacts during migration of neuroblasts to their final destination, as well as the presence of GM3 ganglioside in proliferative cells in the ventricular zone of the telencephalic wall was also recorded.     

Effects of Chronic GM1 Ganglioside Treatment on Cognitieve and Motor Deficits in a Slowly Progressing Model of Parkinsonism in Non-Human Primates

This study examined the effects of chronic GM1 ganglioside administration on the evolution of cognitive and motor deficits in monkeys exposed to low doses of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) over an extended period of time. Monkeys were administered low doses of MPTP for 26 weeks. Once stable cognitive deficits and minimal motor deficits were observed, animals were randomized to saline (N = 2) or GM1 ganglioside (N = 3) treatment groups. Treatments were administered for 90 weeks concurrent with continued low dose MPTP administration. During the first phase of the study (treatment 1-31), GM1 administration ameliorated cognitive deficits and protected against further cognitive decline. Cognitieve deficits worsened in saline-treated animals during this period. In the second phase of the study (weeks 32-52) MPTP dose were increased to enhance the severity of the parkinsonism. GM1-treated animals had delayed onset of motor deficits and a continued preservation of cognitive function. Cognitive and motor function declined in the saline-treated group. In the final phase of the study (weeks 53-90), MPTP doses were lowered back to the levels used during the intial phase of study. GM1-treated animals had significant recovery of motor function, while motor and cognitive function continued to be severely impaired in the saline-treated group. These results suggest that chronic GM1 treatment could be useful in the long-term treatment of Parkinson's disease.     

Imaging and Spectral Characteristics of Amyloid Plaque Autofluorescence in Brain Slices from the APP/PS1 Mouse Model of Alzheimer's Disease

Amyloid deposits are one of the hallmark pathological lesions of Alzheimer's disease(AD). They can be visualized by thioflavin-S, silver impregnation,Congo red staining, and immunohistochemical reactions.However, that amyloid deposits generate blue autofluorescence(auto-F) has been ignored. Here, we report that visible light-induced auto-F of senile plaques(SPs) was detected and validated with conventional methods. Brain slices from APP/PS1(amyloid precursor protein/presenilin1) transgenic mice were mounted on slides, rinsed,coverslipped and observed for details of the imaging and spectral characteristics of the auto-F of SPs. Then the slices were treated with the above classic methods for comparative validation. We found that the SP auto-F was greatest under blue-violet excitation with a specific emission spectrum, and was much easier, more sensitive, and reliable than the classic methods. Because it does not damage slices, observation of auto-F can be combined with all post-staining techniques in slices and for brain-wide imaging in AD.     

格林-巴利综合征患者的GM1抗体与空肠弯曲菌感染的关系

目的　检测GBS患者血清中的GM1抗体 ,并且观察其与CJ抗体的关系 ,以试图发现CJ是否是通过GM 1样结构致敏导致GBS的发生。方法　用间接ELISA法在 81例GBS患者、34例其他神经疾病患者 (OND)和 6 3例正常对照 (NC)的血清测定了CJ抗体和GM 1抗体。结果　GBS组IgM型抗体和IgG型抗体的阳性率分别为 30 .9%和 34.6 % ,与OND组和NC组差异均有显著性。在IgM型GM 1抗体阳性的GBS患者 6 8%有CJ近期感染 ,IgG型GM1抗体阳性的患者 5 3.6 %有CJ近期感染。IgM型GM 1抗体与IgM型CJ抗体和CJ近期感染有关 ,而IgG型GM1抗体与IgG型CJ抗体和CJ近期感染无关。结论　IgM型GM 1抗体与CJ近期感染有关 ,而IgG型GM 1抗体与CJ近期感染无关。CJ感染后可通过GM1样结构发生交叉反应导致神经组织结构和功能的改变 ,但并非所有GM1抗体均为CJ感染引起的     

Knockdown of Acid-Sensing Ion Channel 1a (ASIC1a) Suppresses Disease Phenotype in SCA1 Mouse Model

The mutated ataxin-1 protein in spinocerebellar ataxia 1 (SCA1) targets Purkinje cells (PCs) of the cerebellum and causes progressive ataxia due to loss of PCs and neurons of the brainstem. The exact mechanism of this cellular loss is still not clear. Currently, there are no treatments for SCA1; however, understanding of the mechanisms that regulate SCA1 pathology is essential for devising new therapies for SCA1 patients. We previously established a connection between the loss of intracellular calcium-buffering and calcium-signalling proteins with initiation of neurodegeneration in SCA1 transgenic (Tg) mice. Recently, acid-sensing ion channel 1a (ASIC1a) have been implicated in calcium-mediated toxicity in many brain disorders. Here, we report generating SCA1 Tg mice in the ASIC1a knockout (KO) background and demonstrate that the deletion of ASIC1a gene expression causes suppression of the SCA1 disease phenotype. Loss of the ASIC1a channel in SCA1/ASIC1a KO mice resulted in the improvement of motor deficit and decreased PC degeneration. Interestingly, the expression of the ASIC1 variant, ASIC1b, was upregulated in the cerebellum of both SCA1/ASIC1a KO and ASIC1a KO animals as compared to the wild-type (WT) and SCA1 Tg mice. Further, these SCA1/ASIC1a KO mice exhibited translocation of PC calcium-binding protein calbindin-D28k from the nucleus to the cytosol in young animals, which otherwise have both cytosolic and nuclear localization. Furthermore, in addition to higher expression of calcium-buffering protein parvalbumin, PCs of the older SCA1/ASIC1a KO mice showed a decrease in morphologic abnormalities as compared to the age-matched SCA1 animals. Our data suggest that ASIC1a may be a mediator of SCA1 pathogenesis and targeting ASIC1a could be a novel approach to treat SCA1.     

胞二磷胆碱、氯脂醒、神经节苷脂对大鼠癫(癎)的影响

目的 探讨胞二磷胆碱、氯脂醒、神经节苷脂(GM1)对青霉素致(癎)大鼠行为学及脑皮层电图的影响,为临床治疗颅脑损伤和外伤后癫(癎)提供理论依据.方法 制作大鼠癫(癎)模型,观察并比较对照组、模型组、胞二磷胆碱组、氯脂醒组、GM1组大鼠的行为学及脑皮层电图表现.结果 胞二磷胆碱、氯脂醒、GM1均不能阻止青霉素诱导的大鼠癫(癎)发作.胞二磷胆碱、GM1可以延长青霉素诱导的大鼠癫(癎)(癎)波潜伏期、阵挛强直波潜伏期,减少阵挛强直总时间.结论 胞二磷胆碱、氯脂醒、GM1均不能阻止青霉素诱导的大鼠癫(癎)发作;胞二磷胆碱、GM1可以延长青霉素诱导的大鼠癫(癎)(癎)波潜伏期、阵挛强直波潜伏期,减少青霉素腹腔注射后50 min内的阵挛强直总时间.     

Overexpression of Cell Cycle Proteins of Peripheral Lymphocytes in Patients with Alzheimer's Disease

ObjectiveBiological markers for Alzheimer''s disease (AD) will help clinicians make objective diagnoses early during the course of dementia. Previous studies have suggested that cell cycle dysregulation begins earlier than the onset of clinical manifestations in AD.MethodsWe examined the lymphocyte expression of cell cycle proteins in AD patients, dementia controls (DC), and normal controls (NC). One-hundred seventeen subjects (36 AD, 31 DC, and 50 NC) were recruited. The cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were measured in peripheral lymphocytes. Cell cycle protein expression in the three groups was compared after adjusting for age and sex.ResultsThe levels of cell cycle proteins CDK2, CDK4, CDK6, cyclin B, and cyclin D were significantly higher in AD patients than in the NC subjects. The DC group manifested intermediate levels of cell cycle proteins compared with the AD patients and the NC subjects. The present study indicates that cell cycle proteins are upregulated in the peripheral lymphocytes of AD patients.ConclusionCell cycle dysregulation in peripheral lymphocytes may present a promising starting point for identifying peripheral biomarkers of AD.     

Rapamycin Delays Disease Onset and Prevents PrP Plaque Deposition in a Mouse Model of Gerstmann-Straussler-Scheinker Disease

Autophagy is a cell survival response to nutrient deprivation that delivers cellular components to lysosomes for digestion. In recent years, autophagy has also been shown to assist in the degradation of misfolded proteins linked to neurodegenerative disease (Ross and Poirier, 2004). In support of this, rapamycin, an autophagy inducer, improves the phenotype of several animal models of neurodegenerative disease. Our Tg(PrP-A116V) mice model Gerstmann-Str?ussler-Scheinker disease (GSS), a genetic prion disease characterized by prominent ataxia and extracellular PrP amyloid plaque deposits in brain (Yang et al., 2009). To determine whether autophagy induction can mitigate the development of GSS, Tg(PrP-A116V) mice were chronically treated with 10 or 20 mg/kg rapamycin intraperitoneally thrice weekly, beginning at 6 weeks of age. We observed a dose-related delay in disease onset, a reduction in symptom severity, and an extension of survival in rapamycin-treated Tg(PrP-A116V) mice. Coincident with this response was an increase in the autophagy-specific marker LC3II, a reduction in insoluble PrP-A116V, and a near-complete absence of PrP amyloid plaques in the brain. An increase in glial cell apoptosis of unclear significance was also detected. These findings suggest autophagy induction enhances elimination of misfolded PrP before its accumulation in plaques. Because ataxia persisted in these mice despite the absence of plaque deposits, our findings also suggest that PrP plaque pathology, a histopathological marker for the diagnosis of GSS, is not essential for the GSS phenotype.     

Sexually Dimorphic Expression of Reelin in the Brain of a Mouse Model of Alzheimer Disease

Recent evidence highlights the protective role of reelin against amyloid β (Aβ)-induced synaptic dysfunction and cognitive impairment in Alzheimer disease (AD). In this study, exploiting TgCRND8 mice that overexpress a mutant form of amyloid β precursor protein (AβPP) and display an early onset of AD neuropathological signs, we addressed the question whether changes of reelin expression eventually precede the appearance of Aβ-plaques in a sex-dependent manner. We show that sex-associated and brain region-specific differences in reelin expression appear long before Aβ-plaque formation. However, in spite of a downregulation of reelin expression compared to males, TgCRND8 females display fewer Aβ-plaques, suggesting that additional factors, other than sex and reelin level, influence amyloidosis in this mouse model.     

Decline in Daily Running Distance Presages Disease Onset in a Mouse Model of ALS

Amyotrophic lateral sclerosis (ALS) is characterized by progressive degeneration of lower motor neurons resulting in paralysis and death. Epidemiological and clinical findings suggest that a decline in athletic performance may presage the clinical onset of ALS, but this possibility has not been tested in an animal model. By placing running wheels in each mouse’s cage to measure their exercise activity, we show that presymptomatic G93A SOD1 ALS mice are more active runners (15–20 km/day) than control mice (7–9 km/day). The ALS mice then exhibit a sharp decline in daily running distance 10–20 days prior to the onset of clinical disease. Within the group of ALS mice, there were no significant correlations between cumulative lifetime running distance and age at clinical disease onset or age at death, suggesting that amount of exercise did not affect the course of the disease process. Our data show that presymptomatic ALS mice have a propensity for running long distances, and then dramatically reduce the amount they run prior to the appearance of clinical symptoms. The monitoring of voluntary running distance may provide a valuable biomarker to evaluate the efficacy of potential therapeutic interventions for ALS in preclinical studies. Daniel A. Bruestle and Roy G. Cutler contributed equally to this work.     

Peripheral intraaxonal storage in Tay-Sachs' disease (GM2-gangliosidosis type 1

Considerable intraaxonal lipid storage was observed in intramuscular nerve fibres mainly of the extraocular muscles and less frequently in limb muscles of a 3-year-old child, which had suffered from Tay-Sachs' disease. Many axons of the small intramuscular nerve twigs and of the terminal and preterminal nerve endings showed spherical and cylindrical enlargements containing granular storage material of the same staining properties as the material in the central nervous system. The identify of the axonal and the neuronal storage material was further confirmed by electron-microscopical demonstration of typical multilamellated cytoplasmic bodies (MCBs) in both of them. In addition, silver impregnation and electron microscopy revealed dystrophic changes with an increase of argyrophilic filamentous material within some of the axonal distensions, indicating that the latter were probably due to both a lipid storage and an unspecific dystrophic process.