Trehalose rescues glial cell dysfunction in striatal cultures from HD R6/1 mice at early postnatal development.

The pathological hallmark of Huntington disease (HD) is the intracellular aggregation of mutant huntingtin (mHTT) in striatal neurons and glia associated with the selective loss of striatal medium-sized spiny neurons. Up to the present, the role of glia in HD is poorly understood and has been classically considered secondary to neuronal disorder. Trehalose is a disaccharide known to possess many pharmacological properties, acting as an antioxidant, a chemical chaperone, and an inducer of autophagy. In this study, we analyzed at an early postnatal development stage the abnormalities observed in striatal glial cell cultures of postnatal R6/1 mice (HD glia), under baseline and stressing conditions and the protective effects of trehalose. Our data demonstrate that glial HD alterations already occur at early stages of postnatal development. After 20 postnatal days in vitro, striatal HD glia cultures showed more reactive astrocytes with increased expression of glial fibrillary acidic protein (GFAP) but with less replication capacity, less A2B5(+) glial progenitors and more microglia than wild-type (WT) cultures. HD glia had lower levels of intracellular glutathione (GSH) and was more susceptible to H2O2 and epoxomicin insults. The amount of expressed GDNF and secreted mature-BDNF by HD astrocytes were much lower than by WT astrocytes. In addition, HD glial cultures showed a deregulation of the major proteolytic systems, the ubiquitin-proteasomal system (UPS), and the autophagic pathway. This produces a defective protein quality control, indicated by the elevated levels of ubiquitination and p62 protein. Interestingly, we show that trehalose, through its capacity to induce autophagy, inhibited p62/SQSTM1 accumulation and facilitated the degradation of cytoplasmic aggregates from mHTT and α-synuclein proteins. Trehalose also reduced microglia activation and reversed the disrupted cytoskeleton of astrocytes accompanied with an increase in the replication capacity. In addition, trehalose up-regulated mature-BDNF neurotrophic factor expression and secretion, probably mediating cytoskeletal organization and helping in vesicular BDNF transport. Together, these findings indicate that glia suffers functional early changes in the disease process, changes that may contribute to HD neurodegeneration. Trehalose could be a very promising compound for treatment of HD and other diseases with abnormal protein aggregates. Furthermore our study identifies glial cells as a novel target for trehalose to induce neurotrophic and neuroprotective actions in HD.

Revisiting genotype-phenotype overlap in neurogenetics: triplet-repeat expansions mimicking spastic paraplegias.

Hereditary spastic paraplegias (HSPs) constitute a heterogeneous group of neurological disorders, characterized primarily by progressive spasticity and weakness of the lower limbs. HSPs are caused by mutations in multiple genes (at least 48 loci and 28 causative genes). The clinical spectrum of HSPs is wide and important differences have been reported between patients with distinct mutations in the same gene, or even between different family members bearing the same mutation. Many patients with HSP present clinical deficits related to the involvement of neuronal systems other than corticospinal tracts, namely, peripheral nerves, sensory, or cerebellar pathways. These cases may be difficult to differentiate from other neurological diseases (e.g., hereditary ataxias), also genetically and clinically heterogeneous. As an illustration of how overlapping this genotype-phenotype relationship is, and the difficulties that it brings upon the development of neurogenetic algorithms and databases, we review the main clinical and genetic features of HSPs, and summarize reports on cases of triplet-repeat spinocerebellar ataxias that can mimic HSP phenotypes. This complex scenario makes the necessity of high-quality, curated mutation databases even more urgent, in order to develop adequate diagnostic guidelines, correct interpretation of genetic testing, and appropriate genetic counseling.

Placebo effect characteristics observed in a single, international, longitudinal study in Huntington's disease.

BACKGROUND: Classically, clinical trials are based on the placebo-control design. Our aim was to analyze the placebo effect in Huntington's disease. METHODS: Placebo data were obtained from an international, longitudinal, placebo-controlled trial for Huntington's disease (European Huntington's Disease Initiative Study Group). One-hundred and eighty patients were evaluated using the Unified Huntington Disease Rating Scale over 36 months. A placebo effect was defined as an improvement of at least 50% over baseline scores in the Unified Huntington Disease Rating Scale, and clinically relevant when at least 10% of the population met it. RESULTS: Only behavior showed a significant placebo effect, and the proportion of the patients with placebo effect ranged from 16% (first visit) to 41% (last visit). Nondepressed patients with better functional status were most likely to be placebo-responders over time. CONCLUSIONS: In Huntington's disease, behavior seems to be more vulnerable to placebo than overall motor function, cognition, and function

Parkin deletion causes cerebral and systemic amyloidosis in human mutated tau over-expressing mice.

Deposition of proteins leading to amyloid takes place in some neurodegenerative diseases such as Alzheimer's disease and Huntington's disease. Mutations of tau and parkin proteins produce neurofibrillary abnormalities without deposition of amyloid. Here we report that mature, parkin null, over-expressing human mutated tau (PK(-/-)/Tau(VLW)) mice have altered behaviour and dopamine neurotransmission, tau pathology in brain and amyloid deposition in brain and peripheral organs. PK(-/-)/Tau(VLW) mice have abnormal behaviour and severe drop out of dopamine neurons in the ventral midbrain, up to 70%, at 12 months and abundant phosphorylated tau positive neuritic plaques, neuro-fibrillary tangles, astrogliosis, microgliosis and plaques of murine beta-amyloid in the hippocampus. PK(-/-)/Tau(VLW) mice have organomegaly of the liver, spleen and kidneys. The electron microscopy of the liver confirmed the presence of a fibrillary protein deposits with amyloid characteristics. There is also accumulation of mouse tau in hepatocytes. These mice have lower levels of CHIP-HSP70, involved in the proteosomal degradation of tau, increased oxidative stress, measured as depletion of glutathione which, added to lack of parkin, could trigger tau accumulation and amyloidogenesis. This model is the first that demonstrates beta-amyloid deposits caused by over-expression of tau and without modification of the amyloid precursor protein, presenilins or secretases. PK(-/-)/Tau(VLW) mice provide a link between the two proteins more important for the pathogenesis of Alzheimer disease.

Cannabinoid CB1 receptors are early downregulated followed by a further upregulation in the basal ganglia of mice with deletion of specific park genes.

This study was designed to examine the type of changes experienced by the CB1 receptor, a key element of the cannabinoid signaling system, in the basal ganglia of different mouse mutants generated by deletion of specific genes associated with the development of Parkinson's disease in humans [PARK1 (alpha-synuclein), PARK2 (parkin) or PARK6 (PINK1)]. We observed that CB1 receptor-mRNA levels were significantly reduced in the caudate-putamen in the three models under examination when animals were analyzed at early phases (< or = 12 months of age). This decrease was, in general, associated with a reduction in CB1 receptor binding in the substantia nigra and the globus pallidus, particularly in the case of alpha-synuclein-deficient mice. By contrast, both parameters, mRNA levels and binding for the CB1 receptor, showed an elevation in the same areas when animals were analyzed at older ages, mainly in the case of the CB1 receptor binding in the substantia nigra. In summary, our data revealed the existence of a biphasic response for CB1 receptors, with losses at early phases, when dopaminergic dysfunction is possibly the major event that takes place, followed by upregulatory responses at advanced phases characterized by the occurrence of evident nigrostriatal pathology including neuronal death in some cases.

Gender differences and estrogen effects in parkin null mice.

Estrogens are considered neurotrophic for dopamine neurons. Parkinson's disease is more frequent in males than in females, and more prevalent in females with short reproductive life. Estrogens are neuroprotective against neurotoxic agents for dopamine neurons in vivo and in vitro. Here, we have investigated the role of estrogens in wild-type (WT) and parkin null mice (PK-/-). WT mice present sexual dimorphisms in neuroprotective mechanisms (Bcl-2/Bax, chaperones, and GSH), but some of these inter-sex differences disappear in PK-/-. Tyrosine hydroxylase (TH) protein and TH+ cells decreased earlier and more severely in female than in male PK-/- mice. Neuronal cultures from midbrain of WT and PK-/- mice were treated with estradiol from 10 min to 48 h. Short-term treatments activated the mitogen-activated protein kinase pathway of WT and PK-/- neurons and the phosphatidylinositol 3'-kinase/AKT/glycogen synthase kinase-3 pathway of WT but not of PK-/- cultures. Long-term treatments with estradiol increased the number of TH+ neurons, the TH expression, and the extension of neurites, and decreased the level of apoptosis, the expression of glial fibrillary acidic protein, and the number of microglial cells in WT but not in PK-/- cultures. The levels of estrogen receptor-alpha were elevated in midbrain cultures and in the striatum of adult PK-/- male mice, suggesting that suppression of parkin changes the estrogen receptor-alpha turnover. From our data, it appears that parkin participates in the cellular estrogen response which could be of interest in the management of parkin-related Parkinson's disease patients.

Quantification of the Light Subunit of Neurofilament Protein in Cerebrospinal Fluid of Huntington's Disease Patients.

 Neurofilament light proteins (NFL) are a structural element of the neuronal cytoskeleton and are released with neuronal damage. Its levels are increased in cerebrospinal fluid (CSF) in the setting of neurodegenerative diseases. We investigated the CSF-NFL levels of Huntington´s disease (HD) patients (participating in a clinical trial SAT-HD) as well as of premanifest carriers and compared their results with a sample of healthy controls and correlated CSF-NFL levels with demographic and clinical variables (baseline demographic characteristics and HD measures of disease severity). CSF levels were significantly higher in all HD subjects [5014.4 (1557.3) ng/l] and pre-manifest carriers [1050 (212.13) ng/l as compared to controls [331.4 (200.2) ng/l] (p<0.00) and were correlated with age (correlation coefficient -0.37, p<0.01) and CAG triplet number (0,51, p<0.05) in the subset of HD patients. NFL levels were not correlated with age in the control group. We did not find any correlation with the remaining variables. These results indicate, as in previous studies, that CSF-NFL levels are a marker of neuronal damage in HD. It seems to be a highly sensitive, but non-specific marker of axonal damage. One of the limitations of our study is a very small number of patients in pre-symptomatic group and lack of individuals with very advanced HD. Further investigations should focus on study of CSF-NFL levels in advanced patients, tracking prospectively CSF-NFL levels and analysing its correlation with the clinical course and usefulness to monitor disease progression, validation and quantification of NFL levels in more accessible biofluids.

Progressive nonfluent aphasia associated with a new mutation V363I in tau gene.

Reported here is a new missense mutation V363I in exon 12 of the microtubule-associated protein tau (MAPT) gene associated with progressive nonfluent aphasia, with onset at the age of 69 years in a woman. Although near mute, she maintained complex activities and had no discernible deficits outside of language until the age of 75 years, when progressive gait and swallowing disturbances appeared. There was a history of late-onset aphasia and apraxia in her father. All of her children were asymptomatic adults, but psycholinguistic abnormalities were detected in those bearing the mutation, consisting of difficulties in comprehension, both reading (symbol discrimination and comprehension of oral spelling) and oral (matching sentences to pictures and comprehension of locative relationships). A mutation-bearing sibling showed no abnormalities at 70 years old, consistent with the limited penetrance expected in late-onset disease. The mutation, corresponding to a highly conserved residue in the fourth tubulin-binding repeat, was not present in 194 normal individuals with the same genetic background.

Parkinsonism and other movement disorders in 23 cases of neurocysticercosis.

INTRODUCTION: Parkinsonism and other movement disorders have been occasionally described in neurocysticercosis (NCC) but their clinical features and pathogenesis are not well understood. METHODS: This is a descriptive study conducted over 20 years. We studied 590 consecutive patients from the NCC Registry at Eugenio Espejo Hospital, Quito, Ecuador, and found 23 subjects who developed movement disorders. We investigated the clinical features, localization of brain lesions, severity of infection and neurological deficit as well as the outcome of the patients. Patients were treated with albendazole, dexamethasone, acetazolamide and surgery. We established the diagnosis of NCC, by absolute, imaging and clinical/exposure criteria. RESULTS: Fifteen patients had parkinsonism, 5 tremor, 2 dystonia and 1 chorea. Patients with chorea and dystonia were young females and had cystic lesions in the thalamus and putamen, respectively. Parkinsonism was more frequent in middle aged subjects with subarachnoid and ventricular cysts, hydrocephalus, brain cysts and frequently abnormal cerebrospinal fluid. After anthelmintic treatment no patient died and all patients with chorea, dystonia and tremor fully recovered; 7 of the 15 patients with parkinsonism required treatment with steroids, surgery and long term l-DOPA therapy. CONCLUSIONS: Chorea and dystonia in NCC are due to selective lesions of the basal ganglia. Parkinsonism, the most common movement disorder in NCC, is not related to specific localization of the lesions but the patients show widespread and large lesions, associated with inflammation and distortions of brain structures. In patients with NCC, chorea, dystonia, tremor have a better prognosis, Parkinsonism has a worse one.

Plasma amyloid-beta, Abeta1-42, load is reduced by haemodialysis.

Patients with chronic renal failure treated with haemodialysis have vascular risk factors that, in the general population, are associated with increased prevalence of Alzheimer's disease (AD). Patients in haemodialysis, however, present different kinds of dementia but they do not have an increased risk of AD. We have hypothesized that amyloid-beta (Abeta)1-42 is washed out from plasma during the dialysis and that this procedure enhances Abeta elimination and reduces the risk of AD. We have measured plasma Abeta1-42 levels in 11 patients with renal failure, before and after haemodialysis. A single procedure reduced the plasma Abeta levels in all subjects with a mean decrement of 30% of baseline. Since Abeta deposition could be altered by certain metals like Cu and Zn, we have also measured the effects of dialysis on the levels of these ions in plasma. We found no changes in levels of Cu and Zn after dialysis. Haemodialysis, therefore, reduces very effectively plasma Abeta without modifying Cu and Zn levels. The potential use of this strategy in patients with AD requires further investigation.

Profile of pridopidine and its potential in the treatment of Huntington disease: the evidence to date.

Huntington disease (HD) is a chronic, genetic, neurodegenerative disease for which there is no cure. The main symptoms of HD are abnormal involuntary movements (chorea and dystonia), impaired voluntary movements (ie, incoordination and gait balance), progressive cognitive decline, and psychiatric disturbances. HD is caused by a CAG-repeat expanded mutation in the HTT gene, which encodes the huntingtin protein. The inherited mutation results in the production of an elongated polyQ mutant huntingtin protein (mHtt). The cellular functions of the Htt protein are not yet fully understood, but the functions of its mutant variant are thought to include alteration of gene transcription and energy production, and dysregulation of neurotransmitter metabolism, receptors, and growth factors. The phenylpiperidines pridopidine (4-[3-methanesulfonyl-phenyl]-1-propyl-piperidine; formerly known as ACR16) and OSU6162 ([S]-[-]-3-[3-methane [sulfonyl-phenyl]-1-propyl-piperidine) are members of a new class of pharmacologic agents known as "dopamine stabilizers". Recent clinical trials have highlighted the potential of pridopidine for symptomatic treatment of patients with HD. More recently, the analysis of HD models (ie, in vitro and in mice) highlighted previously unknown effects of pridopidine (increase in brain-derived neurotrophic factor, reduction in mHtt levels, and σ-1 receptor binding and modulation). These additional functions of pridopidine suggest it might be a neuroprotective and disease-modifying drug. Data from ongoing clinical trials of pridopidine will help define its place in the treatment of HD. This commentary examines the available preclinical and clinical evidence regarding the use of pridopidine in HD.

Progressive supranuclear palsy and tau hyperphosphorylation in a patient with a C212Y parkin mutation.

Autosomal recessive-juvenile parkinsonism (AR-JP) is one of the most common forms of familial Parkinson's disease (PD) and is related to mutations in the Park-2 gene, encoding for a protein ligase of ubiquitin, parkin. Different mutations located along the parkin gene have been observed in different AR-JP affected families, possibly interfering with the normal function of parkin and the proteasome system. Two cases of patients with AR-JP have been recently described presenting different homo- and heterozygous parkin mutations and limited tau pathology. We report here the case of a patient with clinical and pathological findings compatible with progressive supranuclear palsy (PSP), carrier of a single, heterozygous mutation of the parkin gene, and homozygous for the H1/H1 haplotype in the tau gene. Abnormal tau hyperphosphorylation has been observed in our patient brain samples, suggesting that a partial deficit of parkin, a protein with ubiquitin-ligase function, may trigger tau pathology in individuals with molecular genetic risk factors.

A two-hybrid screening of human Tau protein: interactions with Alu-derived domain.

The microtubule associated protein tau has been implicated in several neurodegenerative diseases, grouped as tauopathies. To search for tau-associated proteins, the two-hybrid system was used with tau as a bait and an adult human brain cDNA library as a source of putative interacting proteins. We have identified two positive clones consisting of an Alu-derived amino acid sequence that binds to tau and show moderate homology with a motif found in several neuronal proteins related to neurodegenerative disorders. We have also demonstrated that the Alu-derived motif interacts in vitro with tau and may be involved in modulation of its phosphorylation. These findings suggest the existence of tau-binding proteins that are able to bind to tau through their Alu-derived sequence in a direct way. The possible interaction of these proteins with tau could play a role in its cellular localization, regulate the amount of phosphorylated tau and also be involved in the pathological processes of tauopathies.

Neurotrophic factors for the investigation and treatment of movement disorders.

Neurotrophic factors (NFs) are proteins that enhance neuronal survival, differentiation, neurotransmitter function and resistance to neurotoxins and lesions. For these reasons the NFs are considered as a new potential therapeutic tool for the treatment of neurodegenerative disorders, a group of diseases that produce the most important cause for disability in the Western world. Some NFs prevent or even reverse the behavioral, biochemical, pharmacological and histological abnormalities observed in several in vitro and in vivo models of neurodegenerative disorders, namely Parkinson's disease. Several NFs have been investigated in primate models of neurological disorders and some of them have been used for patients with these diseases. The results so far obtained in humans have been disappointing for several reasons, including technical problems for delivery, unbearable side effects or lack of efficacy. Future approaches for the use of NFs in humans should include the following: (1) Investigation of the putative compounds in animal models more related to the pathophysiology of each disease, such as in genetic models of neurodegenerative diseases; (2) New methods of delivery including genetic engineering by viral vectors and administration through implantable devices; (3) More precise methods of continuous response evaluation, including the novel neuroimaging techniques; (4) Investigation of the effects of behavioral stimulation and conventional pharmacotherapy on the metabolism of NFs.

Trehalose reverses cell malfunction in fibroblasts from normal and Huntington's disease patients caused by proteosome inhibition.

Huntington's disease (HD) is a neurodegenerative disorder characterized by progressive motor, cognitive and psychiatric deficits, associated with predominant loss of striatal neurons and is caused by polyglutamine expansion in the huntingtin protein. Mutant huntingtin protein and its fragments are resistant to protein degradation and produce a blockade of the ubiquitin proteasome system (UPS). In HD models, the proteasome inhibitor epoxomicin aggravates protein accumulation and the inductor of autophagy, trehalose, diminishes it. We have investigated the effects of epoxomicin and trehalose in skin fibroblasts of control and HD patients. Untreated HD fibroblasts have increased the levels of ubiquitinized proteins and higher levels of reactive oxygen species (ROS), huntingtin and the autophagy marker LAMP2A. Baseline replication rates were higher in HD than in controls fibroblasts but that was reverted after 12 passages. Epoxomicin increases the activated caspase-3, HSP70, huntingtin, ubiquitinated proteins and ROS levels in both HD and controls. Treatment with trehalose counteracts the increase in ROS, ubiquitinated proteins, huntingtin and activated caspase-3 levels induced by epoxomicin, and also increases the LC3 levels more in HD fibroblast than controls. These results suggest that trehalose could revert protein processing abnormalities in patients with Huntington's Disease.

One-year safety and tolerability profile of pridopidine in patients with Huntington disease.

OBJECTIVE: To assess the 1-year safety profile of the dopaminergic stabilizer pridopidine in patients with Huntington disease. METHODS: Patients received pridopidine 45 mg/day for 4 weeks then pridopidine 90 mg/day for 22 weeks in this 6-month open-label extension (OLE) of the 6-month MermaiHD randomized controlled trial (RCT). Any adverse events (AEs) were recorded. Patients were categorized by their RCT treatment group (placebo, pridopidine 45 mg/day, pridopidine 90 mg/day). RESULTS: Of the 386 patients who completed the RCT, 353 entered the OLE and 305 (86.4%) completed. In 1 year, similar percentages of patients from each group reported ≥1 AE (placebo, 79.6% [n = 90/113]; 45 mg/day, 80.8% [n = 101/125]; 90 mg/day, 82.6% [n = 95/115]) and ≥1 serious AE (8.0% [n = 9/113], 12.8% [n = 16/125], and 8.7% [n = 10/115], respectively). The AE profile across both studies was similar; falls and worsening of chorea were most commonly reported. During the OLE, more patients previously receiving pridopidine reported ≥1 AE (67.9% [n = 163/240]) than those who had received placebo (56.6% [n = 64/113]). Early in the RCT, small increases in heart rate were reported in patients receiving pridopidine. During 1 year, no clinically meaningful changes in laboratory parameters or EKG-related safety concerns were identified. CONCLUSION: Pridopidine (≤90 mg/day) has an acceptable safety profile and is well-tolerated for 1 year. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that pridopidine (≤90 mg/day) is generally safe and well-tolerated in patients with Huntington disease for up to 1 year.