CiteULike: Author Trojanowski

New directions for frontotemporal dementia drug discovery.

JQ Trojanowski — 2008-07-21T09:47:51-00:00

Alzheimer's & dementia : the journal of the Alzheimer's Association, Vol. 4, No. 2. (March 2008), pp. 89-93.

This report summarizes the recommendations of the Frontotemporal Dementia (FTD) Working Group on FTD Drug Discovery that was part of an international FTD Workshop held on January 18 and 19, 2007, in Miami, Florida. The workshop was sponsored by the National Institute of Neurological Disorders and Stroke (NINDS) and the National Institute on Aging (NIA) of the National Institutes of Health (NIH) and the Association for Frontotemporal Dementia (AFTD) with the express purpose of defining opportunities to improve the diagnosis and treatment of patients affected by a neurodegenerative disorder classified as one of the many variants of FTD. The recognition that almost all forms of FTD are due to TDP-43 proteinopathies and tauopathies creates new opportunities for FTD drug discovery targeting pathways of TDP-43 and tau-mediated neurodegeneration.

CSF biomarkers in frontotemporal lobar degeneration with known pathology.

H Bian — 2008-06-10T00:58:12-00:00

Neurology, Vol. 70, No. 19 Pt 2. (6 May 2008), pp. 1827-1835.

OBJECTIVE: To evaluate the diagnostic value of CSF biomarkers in patients with known pathology due to frontotemporal lobar degeneration (FTLD). BACKGROUND: It is important to distinguish FTLD from other neurodegenerative diseases like Alzheimer disease (AD), but this may be difficult clinically because of atypical presentations. METHODS: Patients with FTLD (n = 30) and AD (n = 19) were identified at autopsy or on the basis of genetic testing at University of Pennsylvania and Erasmus University Medical Center. CSF was obtained during a diagnostic lumbar puncture and was analyzed using assays for total tau and amyloid-beta 1-42 (A beta(42)). Patients also were assessed with a brief neuropsychological battery. RESULTS: CSF total tau level and the ratio of CSF total tau to A beta(42) (tau/A beta(42)) were significantly lower in FTLD than in AD. Receiver operating characteristic curve analyses confirmed that the CSF tau/A beta(42) ratio is sensitive and specific at discriminating between FTLD and AD, and is more successful at this than CSF total tau alone. Although some neuropsychological measures are significantly different in autopsy-proven FTLD and AD, combining these neuropsychological measures with CSF biomarkers did not improve the ability to distinguish FTLD from AD. CONCLUSIONS: The ratio of CSF tau/A beta(42) is a sensitive and specific biomarker at discriminating frontotemporal lobar degeneration from Alzheimer disease in patients with known pathology.

Enrichment of C-Terminal Fragments in TAR DNA-Binding Protein-43 Cytoplasmic Inclusions in Brain but not in Spinal Cord of Frontotemporal Lobar Degeneration and Amyotrophic Lateral Sclerosis.

Lionel M Igaz — 2008-06-10T00:56:07-00:00

The American journal of pathology (5 June 2008)

TAR DNA-binding protein (TDP-43) has been recently described as a major pathological protein in both frontotemporal dementia with ubiquitin-positive inclusions (FTLD-U) and amyotrophic lateral sclerosis. However, little is known about the relative abundance and distribution of different pathological TDP-43 species, which include hyperphosphorylated, ubiquitinated, and N-terminally cleaved TDP-43. Here, we developed novel N-terminal (N-t) and C-terminal (C-t)-specific TDP-43 antibodies and performed biochemical and immunohistochemical studies to analyze cortical, hippocampal, and spinal cord tissue from frontotemporal dementia with ubiquitin-positive inclusions and amyotrophic lateral sclerosis cases. C-t-specific TDP-43 antibodies revealed similar abundance, morphology, and distribution of dystrophic neurites and neuronal cytoplasmic inclusions in cortex and hippocampus compared with previously described pan-TDP-43 antibodies. By contrast, N-t-specific TDP-43 antibodies only detected a small subset of these lesions. Biochemical studies confirmed the presence of C-t TDP-43 fragments but not extreme N-t fragments. Surprisingly, immunohistochemical analysis of inclusions in spinal cord motor neurons in both diseases showed that they are N-t and C-t positive. TDP-43 inclusions in Alzheimer's disease brains also were examined, and similar enrichment in C-t TDP-43 fragments was observed in cortex and hippocampus. These results show that the composition of the inclusions in brain versus spinal cord tissues differ, with an increased representation of C-t TDP-43 fragments in cortical and hippocampal regions. Therefore, regionally different pathogenic processes may underlie the development of abnormal TDP-43 proteinopathies.

Cytoskeletal requirements in axonal transport of slow component-b.

S Roy — 2008-05-28T12:02:51-00:00

The Journal of neuroscience : the official journal of the Society for Neuroscience, Vol. 28, No. 20. (14 May 2008), pp. 5248-5256.

Slow component-b (SCb) translocates approximately 200 diverse proteins from the cell body to the axon and axon tip at average rates of approximately 2-8 mm/d. Several studies suggest that SCb proteins are cotransported as one or more macromolecular complexes, but the basis for this cotransport is unknown. The identification of actin and myosin in SCb led to the proposal that actin filaments function as a scaffold for the binding of other SCb proteins and that transport of these complexes is powered by myosin: the "microfilament-complex" model. Later, several SCb proteins were also found to bind F-actin, supporting the idea, but despite this, the model has never been directly tested. Here, we test this model by disrupting the cytoskeleton in a live-cell model system wherein we directly visualize transport of SCb cargoes. We focused on three SCb proteins that we previously showed were cotransported in our system: alpha-synuclein, synapsin-I, and glyceraldehyde-3-phosphate dehydrogenase. Disruption of actin filaments with latrunculin had no effect on the velocity or frequency of transport of these three proteins. Furthermore, cotransport of these three SCb proteins continued in actin-depleted axons. We conclude that actin filaments do not function as a scaffold to organize and transport these and possibly other SCb proteins. In contrast, depletion of microtubules led to a dramatic inhibition of vectorial transport of SCb cargoes. These findings do not support the microfilament-complex model, but instead indicate that the transport of protein complexes in SCb is powered by microtubule motors.

Longitudinal decline in autopsy-defined frontotemporal lobar degeneration

M Grossman — 2008-05-27T20:39:22-00:00

Neurology, Vol. 70, No. 22. (27 May 2008), pp. 2036-2045.

Background: The natural history of patients with pathologically proven frontotemporal lobar degeneration (FTLD) is important from clinical and biologic perspectives, but is not well documented quantitatively. Methods: We examine longitudinal decline in cognitive functioning in an autopsy-proven cohort of patients with the clinical diagnosis of a FTLD spectrum disorder or FTLD pathology using a panel of neuropsychological measures. Patients are categorized according to findings at autopsy into tau-positive FTLD, tau-negative FTLD, and frontal variant-Alzheimer disease (fvAD) subgroups. Results: Patients decline significantly over time on all neuropsychological measures. Moreover, several measures differentiate between histopathologically distinct subgroups throughout the course of the disease process. This includes a significant double dissociation involving relative difficulty on a visual constructional measure in tau-positive patients compared to relatively impaired visual confrontation naming in tau-negative patients. Longitudinal measures of FAS naming fluency and animal naming fluency also distinguish tau-positive patients and tau-negative patients with FTLD from patients with fvAD. Other measures show significant decline but do not distinguish between histopathologic groups longitudinally. Conclusion: Our findings suggest different longitudinal patterns of cognitive decline in pathologically defined subgroups of patients. Measures consistently distinguishing between patient subgroups can be used to bolster diagnostic accuracy throughout the course of these diseases, while measures demonstrating undifferentiated longitudinal decline may serve as useful endpoints in treatment trials. 10.1212/01.wnl.0000303816.25065.bc

Synucleins Are Developmentally Expressed, and alpha -Synuclein Regulates the Size of the Presynaptic Vesicular Pool in Primary Hippocampal Neurons

Diane Murphy — 2008-05-27T15:16:14-00:00

J. Neurosci., Vol. 20, No. 9. (1 May 2000), pp. 3214-3220.

[alpha] -, [beta]-, and [gamma]-Synuclein, a novel family of neuronal proteins, has become the focus of research interest because [alpha]-synuclein has been increasingly implicated in the pathogenesis of Parkinson's and Alzheimer's disease. However, the normal functions of the synucleins are still unknown. For this reason, we characterized [alpha]-, [beta]-, and [gamma]-synuclein expression in primary hippocampal neuronal cultures and showed that the onset of [alpha]- and [beta]-synuclein expression was delayed after synaptic development, suggesting that these synucleins may not be essential for synapse formation. In mature cultured primary neurons, [alpha]- and [beta]-synuclein colocalized almost exclusively with synaptophysin in the presynaptic terminal, whereas little [gamma]-synuclein was expressed at all. To assess the function of [alpha]-synuclein, we suppressed expression of this protein with antisense oligonucleotide technology. Morphometric ultrastructural analysis of the [alpha]-synuclein antisense oligonucleotide-treated cultures revealed a significant reduction in the distal pool of synaptic vesicles. These data suggest that one function of [alpha]-synuclein may be to regulate the size of distinct pools of synaptic vesicles in mature neurons.

Alpha-synuclein in Lewy bodies.

MG Spillantini — 2008-05-27T15:03:10-00:00

Nature, Vol. 388, No. 6645. (28 August 1997), pp. 839-840.

Distinct MRI atrophy patterns in autopsy-proven Alzheimer's disease and frontotemporal lobar degeneration.

GD Rabinovici — 2008-04-02T01:24:09-00:00

American journal of Alzheimer's disease and other dementias, Vol. 22, No. 6. (n 2007), pp. 474-488.

To better define the anatomic distinctions between Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD), we retrospectively applied voxel-based morphometry to the earliest magnetic resonance imaging scans of autopsy-proven AD (N = 11), FTLD (N = 18), and controls (N = 40). Compared with controls, AD patients showed gray matter reductions in posterior temporoparietal and occipital cortex; FTLD patients showed atrophy in medial prefrontal and medial temporal cortex, insula, hippocampus, and amygdala; and patients with both disorders showed atrophy in dorsolateral and orbital prefrontal cortex and lateral temporal cortex (P(FWE-corr) < .05). Compared with FTLD, AD patients had decreased gray matter in posterior parietal and occipital cortex, whereas FTLD patients had selective atrophy in anterior cingulate, frontal insula, subcallosal gyrus, and striatum (P < .001, uncorrected). These findings suggest that AD and FTLD are anatomically distinct, with degeneration of a posterior parietal network in AD and degeneration of a paralimbic fronto-insular-striatal network in FTLD.

TARDBP mutations in amyotrophic lateral sclerosis with TDP-43 neuropathology: a genetic and histopathological analysis.

Vivianna M Van Deerlin — 2008-04-09T19:57:14-00:00

Lancet neurology (4 April 2008)

BACKGROUND: TDP-43 is a major component of the ubiquitinated inclusions that characterise amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD) with ubiquitin inclusions (FTLD-U). TDP-43 is an RNA-binding and DNA-binding protein that has many functions and is encoded by the TAR DNA-binding protein gene (TARDBP) on chromosome 1. Our aim was to investigate whether TARDBP is a candidate disease gene for familial ALS that is not associated with mutations in superoxide dismutase 1 (SOD1). METHODS: TARDBP was sequenced in 259 patients with ALS, FTLD, or both. We used TaqMan-based SNP genotyping to screen for the identified variants in control groups matched to two kindreds of patients for age and ethnic origin. Additional clinical, genetic, and pathological assessments were made in these two families. FINDINGS: We identified two variants in TARDBP, which would encode Gly290Ala and Gly298Ser forms of TDP-43, in two kindreds with familial ALS. The variants seem to be pathogenic because they co-segregated with disease in both families, were absent in controls, and were associated with TDP-43 neuropathology in both members of one of these families for whom CNS tissue was available. INTERPRETATION: The Gly290Ala and Gly298Ser mutations are located in the glycine-rich domain of TDP-43, which regulates gene expression and mediates protein-protein interactions such as those with heterogeneous ribonucleoproteins. Owing to the varied and important cellular functions of TDP-43, these mutations might cause neurodegeneration through both gains and losses of function. The finding of pathogenic mutations in TARDBP implicates TDP-43 as an active mediator of neurodegeneration in TDP-43 proteinopathies, a class of disorder that includes ALS and FTLD-U. FUNDING: National Institutes of Health (AG10124, AG17586, AG005136-22, PO1 AG14382), Department of Veterans Affairs, Friedrich-Baur Stiftung (0017/2007), US Public Health Service, ALS Association, and Fundació 'la Caixa'.

Disturbance of nuclear and cytoplasmic Tar DNA binding protein (TDP-43) induces disease-like redistribution, sequestration and aggregate formation.

Matthew J Winton — 2008-02-29T20:57:01-00:00

J Biol Chem (27 February 2008)

TAR DNA binding protein 43 (TDP-43) is the disease protein in frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) and amyotrophic lateral sclerosis (ALS). While normal TDP-43 is a nuclear protein, pathological TDP-43 is redistributed and sequestered as insoluble aggregates in neuronal nuclei, perikarya and neurites. Here we recapitulate these pathological phenotypes in cultured cells by altering endogenous TDP-43 nuclear trafficking and by expressing mutants with defective nuclear localization (TDP-43-NLS) or nuclear export signals (TDP-43-NES). Restricting endogenous cytoplasmic TDP-43 from entering the nucleus or preventing its exit out of the nucleus resulted in TDP-43 aggregate formation. TDP-43-NLS accumulates as insoluble cytoplasmic aggregates and sequesters endogenous TDP-43, thereby depleting normal nuclear TDP-43; whereas TDP-43-NES forms insoluble nuclear aggregates with endogenous TDP-43. Mutant forms of TDP-43 also replicate the biochemical profile of pathological TDP-43 in FTLD-U/ALS. Thus, FTLD-U/ALS pathogenesis may be linked mechanistically to deleterious perturbations of nuclear trafficking and solubility of TDP-43.

Corticobasal syndrome and primary progressive aphasia as manifestations of LRRK2 gene mutations

AS Chen-Plotkin — 2008-02-11T22:07:32-00:00

Neurology, Vol. 70, No. 7. (12 February 2008), pp. 521-527.

Background: Mutations in the LRRK2 gene are an important cause of familial and nonfamilial parkinsonism. Despite pleomorphic pathology, LRRK2 mutations are believed to manifest clinically as typical Parkinson disease (PD). However, most genetic screens have been limited to PD clinic populations. Objective: To clinically characterize LRRK2 mutations in cases recruited from a spectrum of neurodegenerative diseases. Methods: We screened for the common G2019S mutation and several additional previously reported LRRK2 mutations in 434 individuals. A total of 254 patients recruited from neurodegenerative disease clinics and 180 neurodegenerative disease autopsy cases from the University of Pennsylvania brain bank were evaluated. Results: Eight cases were found to harbor a LRRK2 mutation. Among patients with a mutation, two presented with cognitive deficits leading to clinical diagnoses of corticobasal syndrome and primary progressive aphasia. Conclusion: The clinical presentation of LRRK2-associated neurodegenerative disease may be more heterogeneous than previously assumed. GLOSSARY: AD = Alzheimer disease; ALS = amyotrophic lateral sclerosis; CBD = corticobasal degeneration; CBS = corticobasal syndrome; CDNR = Center for Neurodegenerative Disease Research; DLB = dementia with Lewy bodies; EPS = extrapyramidal symptoms; FTD = frontotemporal dementia; FTLD = frontotemporal lobar degeneration; FWHM = full width at half maximum; LBVAD = Lewy body variant of AD; PD = Parkinson disease; PPA = primary progressive aphasia; PSP = progressive supranuclear palsy; UPenn = University of Pennsylvania; UCSF = University of California San Francisco. 10.1212/01.WNL.0000280574.17166.26

Variations in the Progranulin Gene Affect Global Gene Expression in Frontotemporal Lobar Degeneration

Alice Chen-Plotkin — 2008-01-26T15:23:26-00:00

Hum. Mol. Genet. (25 January 2008), ddn023.

Frontotemporal lobar degeneration is a fatal neurodegenerative disease that results in progressive decline in behavior, executive function, and sometimes language. Disease mechanisms remain poorly understood. Recently, however, the DNA- and RNA-binding protein TDP-43 has been identified as the major protein present in the hallmark inclusion bodies of frontotemporal lobar degeneration with ubiquitinated inclusions (FTLD-U), suggesting a role for transcriptional dysregulation in FTLD-U pathophysiology. Using the Affymetrix U133A microarray platform, we profiled global gene expression in both histopathologically affected and unaffected areas of human FTLD-U brains. We then characterized differential gene expression with biological pathway analyses, cluster and principal component analyses, and subgroup analyses based on brain region and progranulin (GRN) gene status. Comparing 17 FTLD-U brains to 11 controls, we identified 414 upregulated and 210 downregulated genes in frontal cortex (p-value <0.001). Moreover, cluster and principal component analyses revealed that samples with mutations or possibly pathogenic variations in the GRN gene (GRN+, 7/17) had an expression signature that was distinct from both normal controls and FTLD-U samples lacking GRN gene variations (GRN-, 10/17). Within the subgroup of GRN+ FTLD-U, we found >1300 dysregulated genes in frontal cortex (p-value <0.001), many participating in pathways uniquely dysregulated in the GRN+ cases. Our findings demonstrate a distinct molecular phenotype for GRN+ FTLD-U, not readily apparent on clinical or histopathological examination, suggesting distinct pathophysiological mechanisms for GRN+ and GRN- subtypes of FTLD-U. In addition, these data from a large number of human brains provide a valuable resource for future testing of disease hypotheses. 10.1093/hmg/ddn023

Rapid and intermittent cotransport of slow component-b proteins.

S Roy — 2008-01-03T14:18:17-00:00

J Neurosci, Vol. 27, No. 12. (21 March 2007), pp. 3131-3138.

After synthesis in neuronal perikarya, proteins destined for synapses and other distant axonal sites are transported in three major groups that differ in average velocity and protein composition: fast component (FC), slow component-a (SCa), and slow component-b (SCb). The FC transports mainly vesicular cargoes at average rates of approximately 200-400 mm/d. SCa transports microtubules and neurofilaments at average rates of approximately 0.2-1 mm/d, whereas SCb translocates approximately 200 diverse proteins critical for axonal growth, regeneration, and synaptic function at average rates of approximately 2-8 mm/d. Several neurodegenerative diseases are characterized by abnormalities in one or more SCb proteins, but little is known about mechanisms underlying SCb compared with FC and SCa. Here, we use live-cell imaging to visualize and quantify the axonal transport of three SCb proteins, alpha-synuclein, synapsin-I, and glyceraldehyde-3-phosphate dehydrogenase in cultured hippocampal neurons, and directly compare their transport to synaptophysin, a prototypical FC protein. All three SCb proteins move rapidly but infrequently with pauses during transit, unlike synaptophysin, which moves much more frequently and persistently. By simultaneously visualizing the transport of proteins at high temporal and spatial resolution, we show that the dynamics of alpha-synuclein transport are distinct from those of synaptophysin but similar to other SCb proteins. Our observations of the cotransport of multiple SCb proteins in single axons suggest that they move as multiprotein complexes. These studies offer novel mechanistic insights into SCb and provide tools for further investigating its role in disease processes.

TDP-43: a novel neurodegenerative proteinopathy.

Mark S Forman — 2007-10-16T20:54:16-00:00

Curr Opin Neurobiol (11 October 2007)

Over the past decade, it has become clear that there is a significant overlap in the clinical spectrum of frontotemporal lobar degeneration and amyotrophic lateral sclerosis (ALS). The identification of TDP-43 as the major disease protein in the pathology of both frontotemporal lobar degeneration with ubiquitin inclusions and ALS provides the first molecular link for these diseases. Pathological TDP-43 is abnormally phosphorylated, ubiquitinated, and cleaved to generate carboxy-terminal fragments in affected brain regions. The normal nuclear expression of TDP-43 is also reduced leading to the hypothesis that sequestration of TDP-43 in pathological inclusions contributes to disease pathogenesis. Thus, TDP-43 is the newest member of the growing list of neurodegenerative proteinopathies, but unique in that it lacks features of brain amyloidosis.

Ways toward an early diagnosis in Alzheimer's disease: The Alzheimer's Disease Neuroimaging Initiative (ADNI).

Susanne G Mueller — 2007-05-23T11:56:12-00:00

Alzheimers Dement, Vol. 1, No. 1. (July 2005), pp. 55-66.

With the increasing life expectancy in developed countries, the incidence of Alzheimer's disease (AD) and thus its socioeconomic impact are growing. Increasing knowledge over the last years about the pathomechanisms involved in AD allow for the development of specific treatment strategies aimed at slowing down or even preventing neuronal death in AD. However, this requires also that (1) AD can be diagnosed with high accuracy, because non-AD dementias would not benefit from an AD-specific treatment; (2) AD can be diagnosed in very early stages when any intervention would be most effective; and (3) treatment efficacy can be reliably and meaningfully monitored. Although there currently is no ideal biomarker that would fulfill all these requirements, there is increasing evidence that a combination of currently existing neuroimaging and cerebrospinal fluid (CSF) and blood biomarkers can provide important complementary information and thus contribute to a more accurate and earlier diagnosis of AD. The Alzheimer's Disease Neuroimaging Initiative (ADNI) is exploring which combinations of these biomarkers are the most powerful for diagnosis of AD and monitoring of treatment effects.

Tau-mediated neurodegeneration in Alzheimer's disease and related disorders

Carlo Ballatore — 2007-08-20T14:22:36-00:00

Nat Rev Neurosci, Vol. 8, No. 9. (2007), pp. 663-672.

A comparison of amyloid fibrillogenesis using the novel fluorescent compound K114.

AS Crystal — 2007-06-28T17:13:29-00:00

J Neurochem, Vol. 86, No. 6. (September 2003), pp. 1359-1368.

Proteinaceous inclusions with amyloidogenic properties are a common link between many neurodegenerative diseases, including Alzheimer's disease and Parkinson's disease. Histological and in vitro studies of amyloid fibrils have advanced the understanding of protein aggregation, and provided important insights into pathogenic mechanisms of these neurodegenerative brain amyloidoses. The classical amyloid dyes Congo Red (CR) and thioflavin T and S, have been used extensively to detect amyloid inclusions in situ. These dyes have also been utilized to monitor the maturation of amyloid fibrils assembled from monomer subunits in vitro. Recently, the compound (trans,trans)-1-bromo-2,5-bis-(3- hydroxycarbonyl-4-hydroxy)styrylbenzene (BSB), derived from the structure of CR, was shown to bind to a wide range of amyloid inclusions in situ. More importantly it was also used to label brain amyloids in live animals. Herein, we show that an analogue of BSB, (trans,trans)-1-bromo-2,5-bis-(4-hydroxy)styrylbenzene (K114), recognizes amyloid lesions, and has distinctive properties which allowed the quantitative monitoring of the formation of amyloid fibrils assembled from the amyloid-beta peptide, alpha-synuclein, and tau.

Pathological TDP-43 distinguishes sporadic amyotrophic lateral sclerosis from amyotrophic lateral sclerosis with SOD1 mutations.

IR Mackenzie — 2007-05-08T15:50:42-00:00

Ann Neurol, Vol. 61, No. 5. (May 2007), pp. 427-434.

OBJECTIVE: Amyotrophic lateral sclerosis (ALS) is a common, fatal motor neuron disorder with no effective treatment. Approximately 10% of cases are familial ALS (FALS), and the most common genetic abnormality is superoxide dismutase-1 (SOD1) mutations. Most ALS research in the past decade has focused on the neurotoxicity of mutant SOD1, and this knowledge has directed therapeutic strategies. We recently identified TDP-43 as the major pathological protein in sporadic ALS. In this study, we investigated TDP-43 in a larger series of ALS cases (n = 111), including familial cases with and without SOD1 mutations. METHODS: Ubiquitin and TDP-43 immunohistochemistry was performed on postmortem tissue from sporadic ALS (n = 59), ALS with SOD1 mutations (n = 15), SOD-1-negative FALS (n = 11), and ALS with dementia (n = 26). Biochemical analysis was performed on representative cases from each group. RESULTS: All cases of sporadic ALS, ALS with dementia, and SOD1-negative FALS had neuronal and glial inclusions that were immunoreactive for both ubiquitin and TDP-43. Cases with SOD1 mutations had ubiquitin-positive neuronal inclusions; however, no cases were immunoreactive for TDP-43. Biochemical analysis of postmortem tissue from sporadic ALS and SOD1-negative FALS demonstrated pathological forms of TDP-43 that were absent in cases with SOD1 mutations. INTERPRETATION: These findings implicate pathological TDP-43 in the pathogenesis of sporadic ALS. In contrast, the absence of pathological TDP-43 in cases with SOD1 mutations implies that motor neuron degeneration in these cases may result from a different mechanism, and that cases with SOD1 mutations may not be the familial counterpart of sporadic ALS. Ann Neurol 2007;61:427-434.

Ubiquitinated TDP-43 in frontotemporal lobar degeneration and amyotrophic lateral sclerosis.

M Neumann — 2006-10-13T17:54:04-00:00

Science, Vol. 314, No. 5796. (6 October 2006), pp. 130-133.

Ubiquitin-positive, tau- and alpha-synuclein-negative inclusions are hallmarks of frontotemporal lobar degeneration with ubiquitin-positive inclusions and amyotrophic lateral sclerosis. Although the identity of the ubiquitinated protein specific to either disorder was unknown, we showed that TDP-43 is the major disease protein in both disorders. Pathologic TDP-43 was hyper-phosphorylated, ubiquitinated, and cleaved to generate C-terminal fragments and was recovered only from affected central nervous system regions, including hippocampus, neocortex, and spinal cord. TDP-43 represents the common pathologic substrate linking these neurodegenerative disorders.

The relationship between oxidative/nitrative stress and pathological inclusions in Alzheimer's and Parkinson's diseases.

BI Giasson — 2007-05-03T15:56:34-00:00

Free Radic Biol Med, Vol. 32, No. 12. (15 June 2002), pp. 1264-1275.

Alzheimer's (AD) and Parkinson's diseases (PD) are late-onset neurodegenerative diseases that have tremendous impact on the lives of affected individuals, their families, and society as a whole. Remarkable efforts are being made to elucidate the dominant factors that result in the pathogenesis of these disorders. Extensive postmortem studies suggest that oxidative/nitrative stresses are prominent features of these diseases, and several animal models support this notion. Furthermore, it is likely that protein modifications resulting from oxidative/nitrative damage contribute to the formation of intracytoplasmic inclusions characteristic of each disease. The frequent presentation of both AD and PD in individuals and the co-occurrence of inclusions characteristic of AD and PD in several other neurodegenerative diseases suggests the involvement of a common underlying aberrant process. It can be surmised that oxidative/nitrative stress, which is cooperatively influenced by environmental factors, genetic predisposition, and senescence, may be a link between these disorders.

Oxidative damage linked to neurodegeneration by selective alpha-synuclein nitration in synucleinopathy lesions.

BI Giasson — 2007-05-03T15:54:46-00:00

Science, Vol. 290, No. 5493. (3 November 2000), pp. 985-989.

Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of neurodegenerative synucleinopathies, and oxidative stress has been implicated in the pathogenesis of some of these disorders. Using antibodies to specific nitrated tyrosine residues in alpha-synuclein, we demonstrate extensive and widespread accumulations of nitrated alpha-synuclein in the signature inclusions of Parkinson's disease, dementia with Lewy bodies, the Lewy body variant of Alzheimer's disease, and multiple system atrophy brains. We also show that nitrated alpha-synuclein is present in the major filamentous building blocks of these inclusions, as well as in the insoluble fractions of affected brain regions of synucleinopathies. The selective and specific nitration of alpha-synuclein in these disorders provides evidence to directly link oxidative and nitrative damage to the onset and progression of neurodegenerative synucleinopathies.

Initiation and Synergistic Fibrillization of Tau and Alpha-Synuclein

Benoit Giasson — 2007-01-09T08:11:18-00:00

Science, Vol. 300, No. 5619. (25 April 2003), pp. 636-640.

Alpha-synuclein (alpha-syn) and tau polymerize into amyloid fibrils and form intraneuronal filamentous inclusions characteristic of neurodegenerative diseases. We demonstrate that alpha-syn induces fibrillization of tau and that coincubation of tau and alpha-syn synergistically promotes fibrillization of both proteins. The in vivo relevance of these findings is grounded in the co-occurrence of alpha-syn and tau filamentous amyloid inclusions in humans, in single transgenic mice that express A53T human alpha-syn in neurons, and in oligodendrocytes of bigenic mice that express wild-type human alpha-syn plus P301L mutant tau. This suggests that interactions between alpha-syn and tau can promote their fibrillization and drive the formation of pathological inclusions in human neurodegenerative diseases. 10.1126/science.1082324

Expression profile of transcripts in Alzheimer's disease tangle-bearing CA1 neurons.

SD Ginsberg — 2006-11-14T01:19:46-00:00

Ann Neurol, Vol. 48, No. 1. (July 2000), pp. 77-87.

The pathogenesis of neurofibrillary tangles (NFTs) in Alzheimer's disease (AD) is poorly understood, but changes in the expression of specific messenger RNAs (mRNAs) may reflect mechanisms underlying the formation of NFTs and their consequences in affected neurons. For these reasons, we compared the relative abundance of multiple mRNAs in tangle-bearing versus normal CA1 neurons aspirated from sections of AD and control brains. Amplified antisense RNA expression profiling was performed on individual isolated neurons for analysis of greater than 18,000 expressed sequence tagged complementary DNAs (cDNAs) with cDNA microarrays, and further quantitative analyses were performed by reverse Northern blot analysis on 120 selected mRNAs on custom cDNA arrays. Relative to normal CA1 neurons, those harboring NFTs in AD brains showed significant reductions in several classes of mRNAs that are known to encode proteins implicated in AD neuropathology, including phosphatases/kinases, cytoskeletal proteins, synaptic proteins, glutamate receptors, and dopamine receptors. Because cathepsin D mRNA was upregulated in NFT-bearing CA1 neurons in AD brains, we performed immunohistochemical studies that demonstrated abundant cathepsin D immunoreactivity in the same population of tangle-bearing CA1 neurons. In addition, levels of mRNAs encoding proteins not previously implicated in AD were reduced in CA1 tangle-bearing neurons, suggesting that these proteins (eg, activity-regulated cytoskeleton-associated protein, focal adhesion kinase, glutaredoxin, utrophin) may be novel mediators of NFT formation or degeneration in affected neurons. Thus, the profile of mRNAs differentially expressed by tangle-bearing CA1 neurons may represent a "molecular fingerprint" of these neurons, and we speculate that mRNA expression profiles of diseased neurons in AD may suggest new directions for AD research or identify novel targets for developing more effective AD therapies.

Single-cell gene expression analysis: implications for neurodegenerative and neuropsychiatric disorders.

SD Ginsberg — 2006-11-14T00:36:46-00:00

Neurochem Res, Vol. 29, No. 6. (June 2004), pp. 1053-1064.

Technical and experimental advances in microaspiration techniques, RNA amplification, quantitative real-time polymerase chain reaction (qPCR), and cDNA microarray analysis have led to an increase in the number of studies of single-cell gene expression. In particular, the central nervous system (CNS) is an ideal structure to apply single-cell gene expression paradigms. Unlike an organ that is composed of one principal cell type, the brain contains a constellation of neuronal and noneuronal populations of cells. A goal is to sample gene expression from similar cell types within a defined region without potential contamination by expression profiles of adjacent neuronal subpopulations and noneuronal cells. The unprecedented resolution afforded by single-cell RNA analysis in combination with cDNA microarrays and qPCR-based analyses allows for relative gene expression level comparisons across cell types under different experimental conditions and disease states. The ability to analyze single cells is an important distinction from global and regional assessments of mRNA expression and can be applied to optimally prepared tissues from animal models as well as postmortem human brain tissues. This focused review illustrates the potential power of single-cell gene expression studies within the CNS in relation to neurodegenerative and neuropsychiatric disorders such as Alzheimer's disease (AD) and schizophrenia, respectively.

Pathological heterogeneity of frontotemporal lobar degeneration with ubiquitin-positive inclusions delineated by ubiquitin immunohistochemistry and novel monoclonal antibodies.

DM Sampathu — 2006-10-18T19:53:17-00:00

Am J Pathol, Vol. 169, No. 4. (October 2006), pp. 1343-1352.

Frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U) is a common neuropathological subtype of frontotemporal dementia. Although this subtype of frontotemporal dementia is defined by the presence of ubiquitin-positive but tau- and alpha-synuclein-negative inclusions, it is unclear whether all cases of FTLD-U have the same underlying pathogenesis. Examination of tissue sections from FTLD-U brains stained with anti-ubiquitin antibodies revealed heterogeneity in the morphological characteristics of pathological inclusions among subsets of cases. Three types of FTLD-U were delineated based on morphology and distribution of ubiquitin-positive inclusions. To address the hypothesis that FTLD-U is pathologically heterogeneous, novel monoclonal antibodies (mAbs) were generated by immunization of mice with high molecular mass (M(r) > 250 kd) insoluble material prepared by biochemical fractionation of FTLD-U brains. Novel mAbs were identified that immunolabeled all of the ubiquitin-positive inclusions in one subset of FTLD-U cases, whereas other mAbs stained the ubiquitin-positive inclusions in a second subset of cases. These novel mAbs did not stain inclusions in other neurodegenerative disorders, including tauopathies and alpha-synucleinopathies. Therefore, ubiquitin immunohistochemistry and the immunostaining properties of the novel mAbs generated here suggest that FTLD-U is pathologically he-terogeneous. Identification of the disease proteins recognized by these mAbs will further advance understanding of molecular substrates of FTLD-U neurodegenerative pathways.

Neurodegenerative diseases: a decade of discoveries paves the way for therapeutic breakthroughs

Mark Forman — 2006-10-18T15:24:21-00:00

Nat Med, Vol. 10, No. 10. (October 2004), pp. 1055-1063.

Expression of GDNF mRNA in rat and human nervous tissue.

JE Springer — 2006-09-09T07:48:23-00:00

Exp Neurol, Vol. 127, No. 2. (June 1994), pp. 167-170.

A recently cloned neurotrophic factor, termed glial cell line-derived neurotrophic factor (GDNF), has been reported to exhibit selective neurotrophic properties on ventral mesencephalon dopaminergic neurons, which degenerate in patients with Parkinson's disease. In the present study, we used reverse transcriptase followed by polymerase chain reaction (PCR) and in situ hybridization to study the expression of GDNF messenger RNA (mRNA) in the adult rat and human central nervous system (CNS). GDNF transcripts were identified using PCR in all regions of the rat CNS analyzed including striatum, hippocampus, cortex, cerebellum, and spinal cord. Interestingly, the rat hippocampal formation contained two transcripts, i.e., a larger form in addition to the amplified GDNF cDNA found in all other areas analyzed. GDNF PCR products also were observed in human striatum, hippocampus, cortex, and spinal cord, but not cerebellum, and both the striatum and hippocampal formation contained two GDNF transcripts. Finally, GDNF transcripts were detected in a rat Schwann cell line previously shown to secrete a factor that exerts a neurotrophic effect on dopaminergic neurons. In situ hybridization experiments using a cRNA probe hybridized to adult rat brain sections demonstrated no positive GDNF mRNA signal. However, intense GDNF mRNA hybridization signal was found to be associated with dorsal root ganglia in Postnatal Day 1 rats. These findings provide evidence that GDNF is detectable using PCR in a number of nervous system structures and, in some areas, GDNF is expressed in more than one form.

Diagnosis and management of dementia with Lewy bodies: Third report of the DLB consortium

IG Mckeith — 2006-03-31T00:12:23-00:00

Neurology, Vol. 65, No. 12. (27 December 2005), pp. 1863-1872.

The dementia with Lewy bodies (DLB) Consortium has revised criteria for the clinical and pathologic diagnosis of DLB incorporating new information about the core clinical features and suggesting improved methods to assess them. REM sleep behavior disorder, severe neuroleptic sensitivity, and reduced striatal dopamine transporter activity on functional neuroimaging are given greater diagnostic weighting as features suggestive of a DLB diagnosis. The 1-year rule distinguishing between DLB and Parkinson disease with dementia may be difficult to apply in clinical settings and in such cases the term most appropriate to each individual patient should be used. Generic terms such as Lewy body (LB) disease are often helpful. The authors propose a new scheme for the pathologic assessment of LBs and Lewy neurites (LN) using alpha-synuclein immunohistochemistry and semiquantitative grading of lesion density, with the pattern of regional involvement being more important than total LB count. The new criteria take into account both Lewy-related and Alzheimer disease (AD)-type pathology to allocate a probability that these are associated with the clinical DLB syndrome. Finally, the authors suggest patient management guidelines including the need for accurate diagnosis, a target symptom approach, and use of appropriate outcome measures. There is limited evidence about specific interventions but available data suggest only a partial response of motor symptoms to levodopa: severe sensitivity to typical and atypical antipsychotics in [~]50%, and improvements in attention, visual hallucinations, and sleep disorders with cholinesterase inhibitors. 10.1212/01.wnl.0000187889.17253.b1

The cytoskeleton in neurodegenerative diseases.

NJ Cairns — 2006-01-09T13:07:50-00:00

J Pathol, Vol. 204, No. 4. (November 2004), pp. 438-449.

Abundant abnormal aggregates of cytoskeletal proteins are neuropathological signatures of many neurodegenerative diseases that are broadly classified by filamentous aggregates of neuronal intermediate filament (IF) proteins, or by inclusions containing the microtubule-associated protein (MAP) tau. The discovery of mutations in neuronal IF and tau genes firmly establishes the importance of neuronal IF proteins and tau in the pathogenesis of neurodegenerative diseases. Multiple IF gene mutations are pathogenic for Charcot-Marie-Tooth (CMT) disease and amyotrophic lateral sclerosis (ALS)--in addition to those in the copper/zinc superoxide dismutase-1 (SOD1) gene. Tau gene mutations are pathogenic for frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), and tau polymorphisms are genetic risk factors for sporadic progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD). Thus, IF and tau abnormalities are linked directly to the aetiology and pathogenesis of neurodegenerative diseases. In vitro and transgenic animal models are being used to demonstrate that different mutations impair protein function, promote tau fibrilization, or perturb tau gene splicing, leading to aberrant and distinct tau aggregates. For recognition of these disorders at neuropathological examination, immunohistochemistry is needed, and this may be combined with biochemistry and molecular genetics to properly determine the nosology of a particular case. As reviewed here, the identification of molecular genetic defects and biochemical alterations in cytoskeletal proteins of human neurodegenerative diseases has facilitated experimental studies and will promote the development of assays of molecules which inhibit abnormal neuronal IF and tau protein inclusions.

Intensive care management of head-injured patients in Europe: a survey from the European brain injury consortium.

N Stocchetti — 2005-08-29T08:34:19-00:00

Intensive Care Med, Vol. 27, No. 2. (February 2001), pp. 400-406.

OBJECTIVES: (a) to describe current practice in the monitoring and treatment of moderate and severe head injuries in Europe; (b) to report on intracranial pressure and cerebral perfusion pressure monitoring, occurrence of measured and reported intracranial hypertension, and complications related to this monitoring; (c) to investigate the relationship between the severity of injury, the frequency of monitoring and management, and outcome. METHODS: A three-page questionnaire comprising 60 items of information has been compiled by 67 centres in 12 European countries. Information was collected prospectively regarding all severe and moderate head injuries in adults (> 16 years) admitted to neurosurgery within 24 h of injury. A total of 1005 adult head injury cases were enrolled in the study from 1 February 1995 to 30 April 1995. The Glasgow Outcome Scale was administered at 6 months. RESULTS: Early surgery was performed in 346 cases (35%); arterial pressure was monitored invasively in 631 (68%), ICP in 346 (37%), and jugular bulb saturation in 173 (18%). Artificial ventilation was provided to 736 patients (78%). Intracranial hypertension was noted in 55% of patients in whom ICP was recorded, while it was suspected in only 12% of cases without ICP measurement. There were great differences in the use of ventilation and CPP monitoring among the centres. Mortality at 6 months was 31%. There was an association between an increased frequency of monitoring and intervention and an increased severity of injury; correspondingly, patients who more frequently underwent monitoring and ventilation had a less favourable outcome. CONCLUSIONS: In Europe there are great differences between centres in the frequency of CPP monitoring and ventilatory support applied to head-injured patients. ICP measurement disclosed a high rate of intracranial hypertension, which was not suspected in patients evaluated on a clinical basis alone. ICP monitoring was associated with a low rate of complications. Cases with severe neurological impairment, and with the worse outcome, were treated and monitored more intensively.