RSSTargeting phospho-Ser422 by active Tau immunotherapy in the THY-Tau22 mouse model: a suitable therapeutic approach.
Source
Inserm UMR837, Alzheimer&Tauopathies, Centre de Recherches Jean-Pierre Aubert, Faculté de Médecine Pole Recherche, Place de Verdun, F-59045 Lille, France. luc.buee@inserm.fr.
Abstract
Recent data indicate that Tau immunotherapy may be relevant for interfering with neurofibrillary degeneration in Alzheimer disease and related disorders referred to as Tauopathies. The key question for immunotherapy is the choice of the epitope to target. Abnormal phosphorylation is a well-described posttranslational modification of Tau proteins and may be a good target. In the present study, we investigated the effects of active immunization against the pathological epitope phospho-Ser422 in the THY-Tau22 transgenic mouse model. Starting from 3-6 months of age, THY-Tau22 mice develop hippocampal neurofibrillary tangle-like inclusions and exhibit phosphorylation of Tau on several AD-relevant Tauepitopes. Three month-old THY-Tau22 mice were immunized with a peptide including the phosphoserine 422 residue while control mice received the adjuvant alone. A specific antibody response against the phospho-Ser422 epitope was observed. We noticed a decrease in insoluble Tau species (AT100- and pS422 immunoreactive) by both biochemical and immunohistochemical means correlated with significant cognitive improvement using the Y-maze. This Tauimmunotherapy may facilitate Tau clearance from the brain toward the periphery since, following immunization, an increase in Tau concentrations was observed in blood. Overall, the present work is, to our knowledge, the first one to demonstrate that active immunotherapy targeting a real pathological epitope such as phospho-Ser422 epitope is efficient. This immunotherapy allows for Tau clearance and improves cognitive deficits promoted by Tau pathology in a well-defined Tau transgenic model.
- PMID:
- 22272619
- [PubMed - as supplied by publisher]
Multiple sclerosis: High-avidity anti-tau antibodies found in patients with MS.
Alzheimer's Disease: APP, Gamma Secretase, APOE, CLU, CR1, PICALM, ABCA7, BIN1, CD2AP, CD33, EPHA1, and MS4A2, and Their Relationships with Herpes Simplex, C. Pneumoniae, Other Suspect Pathogens, and the Immune System.
Source
PolygenicPathways, Flat 2, 40 Baldslow Road, Hastings, East Sussex TN34 2EY, UK.
Abstract
Alzheimer's disease susceptibility genes, APP and gamma-secretase, are involved in the herpes simplex life cycle, and that of other suspect pathogens (C. pneumoniae, H. pylori, C. neoformans, B. burgdorferri, P. gingivalis) or immune defence. Such pathogens promote beta-amyloid deposition and tau phosphorylation and may thus be causative agents, whose effects are conditioned by genes. The antimicrobial effects of beta-amyloid, the localisation of APP/gamma-secretase in immunocompetent dendritic cells, and gamma secretase cleavage of numerous pathogen receptors suggest that this network is concerned with pathogen disposal, effects which may be abrogated by the presence of beta-amyloid autoantibodies in the elderly. These autoantibodies, as well as those to nerve growth factor and tau, also observed in Alzheimer's disease, may well be antibodies to pathogens, due to homology between human autoantigens and pathogen proteins. NGF or tau antibodies promote beta-amyloid deposition, neurofibrillary tangles, or cholinergic neuronal loss, and, with other autoantibodies, such as anti-ATPase, are potential agents of destruction, whose formation is dictated by sequence homology between pathogen and human proteins, and thus by pathogen strain and human genes. Pathogen elimination in the ageing population and removal of culpable autoantibodies might reduce the incidence and offer hope for a cure in this affliction.
Identification of oligomers at early stages of tau aggregation in Alzheimer's disease.
Source
*George P. and Cynthia Woods Mitchell Center for Neurodegenerative Diseases.
Abstract
Neurofibrillary tangles (NFTs) are a pathological hallmark of Alzheimer's disease (AD); however, the relationship between NFTs and disease progression remains controversial. Analyses of tau animal models suggest that phenotypes coincide with accumulation of soluble aggregated tau species but not the accumulation of NFTs. The pathological role of prefilamentous tau aggregates, e.g., tau oligomeric intermediates, is poorly understood, in part because of methodological challenges. Here, we engineered a novel tau oligomer-specific antibody, T22, and used it to elucidate the temporal course and biochemical features of oligomers during NFT development in AD brain. We found that tauoligomers in human AD brain samples were 4-fold higher than those in the controls. We also revealed the role of oligomeric tau conformers in pretangles, neuritic plaques, and neuropil threads in the frontal cortex tissue from AD brains; this analysis uncovers a consistent code that governs tau oligomerization with regard to degree of neuronal cytopathology. These data are the first to characterize the role of tau oligomers in the natural history of NFTs, and they highlight the suitability of tau oligomers as therapeutic targets in AD and related tauopathies.-Lasagna-Reeves, C. A., Castillo-Carranza, D. L., Sengupta, U., Troncoso, J., Jackson, G. R., Kayed, R. Identification of oligomers at early stages of tau aggregation in Alzheimer's disease.
Long-term oral lithium treatment attenuates motor disturbance in tauopathy model mice: Implications of autophagy promotion.
Source
Department of Neurology, Juntendo University School of Medicine, Tokyo, Japan; Department of Pharmacy, Juntendo University School of Medicine, Tokyo, Japan; Department of Pharmacy, Juntendo Tokyo Koto Geriatric Medical Center, Tokyo, Japan(f).
Abstract
Lithium, a drug used to treat bipolar disorders, has a variety of neuroprotective mechanisms including inhibition of glycogen synthase kinase-3 (GSK-3), a major tau kinase. Recently, it has been shown that, in various neurodegenerative proteinopathies, lithium could induce autophagy. To analyze how lithium is therapeutically beneficial in tauopathies, transgenic mice overexpressing human mutant tau (P301L) were treated with oral lithium chloride (LiCl) for 4months starting at the age of 5months. At first, we examined the effects of treatment on behavior (using a battery of behavioral tests), tau phosphorylation (by biochemical assays), and number of neurofibrillary tangles (NFTs) (by immunohistopathology). In comparison with control mice, LiCl-treated mice showed a significantly better score in the sensory motor tasks, as well as decreases in tau phosphorylation, soluble tau level, and number of NFTs. Next, we examined lithium effects on autophagy using an antibody against microtubule-associated protein 1 light chain 3 (LC3) as an autophagosome marker. The number of LC3-positive autophagosome-like puncta was increased in neurons of LiCl-treated mice. Neurons containing NFTs were completely LC3-negative, whereas LC3-positive autophagosome-like puncta contained phosphorylated-tau (p-tau). The protein level of p62 was decreased in LiCl-treated mice. These data suggested that oral long-term lithium treatment could attenuate p-tau-induced motor disturbance not only by inhibiting GSK-3 but also by enhancing autophagy in tauopathy model mice.
Copyright © 2012. Published by Elsevier Inc.
Widespread neuronal and glial hyperphosphorylated tau deposition in ALS with cognitive impairment.
Source
Robarts Research Institute, The University of Western Ontario.
Abstract
Although the biological basis of frontotemporal syndromes associated with amyotrophic lateral sclerosis (ALS) is considered to be altered metabolism of TDP-43, in ALS with cognitive impairment (ALSci) the metabolism of tau protein is also altered. This includes neuronal hyperphosphorylation (pThr(175)). Using novel polyclonal phospho-tau antibodies(pSer(208, 210), pThr(217) and pThr(175)) and antibodies directed against PHF tau (pSer(202)), TDP-43 or ubiquitin, we characterized tau deposition in ALS and ALSci. In ALS, we observed pThr(175) tau immunoreactive intraneuronal and neuritic aggregates throughout the amygdala and entorhinal cortex. In ALSci, this extended to the anterior cingulate gyrus, superior frontal cortex and substantia nigra. The pThr(217) antibody detected widespread astrocytic taudeposition, including punctuate or fibrillary aggregates, or intensely immunoreactive tufted astrocytes in the superior frontal cortex, anterior cingulate gyrus, entorhinal cortex, amygdala and basal ganglia of ALS. In ALSci, a similar but more widely distributed pThr(217) pathology was observed. There was no correlation between the extent of pathologicaltau deposition and TDP-43 pathology, although nuclear TDP-43 immunoreactivity was absent in neurons with taupathology. In conclusion, ALSci is unique in possessing both tau and TDP-43 pathology. The presence of widespread astrocytic tau pathology suggests that ALSci may initially be characterized by astrocytic pathology.
- PMID:
- 22214313
- [PubMed - as supplied by publisher]
Increased intrathecal high-avidity anti-tau antibodies in patients with multiple sclerosis.
Source
Institute of Medical Biochemistry, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic.
Abstract
BACKGROUND:
Antibodies against tau protein indicate an interaction between the immune system and the neurocytoskeleton and therefore may reflect axonal injury in multiple sclerosis (MS).
METHODOLOGY/PRINCIPAL FINDINGS:
The levels and avidities of anti-tau IgG antibodies were measured using ELISA in paired cerebrospinal fluid (CSF) and serum samples obtained from 49 MS patients and 47 controls. Anti-tauantibodies were significantly elevated intrathecally (p<0.0001) in the MS group. The CSF anti-tau antibody levels were lower in MS patients receiving therapy than those without treatment (p<0.05). The avidities of anti-tau antibodies were higher in the CSF than in the serum (MS group p<0.0001; controls p<0.005). Anti-tau avidities in the CSF were elevated in MS patients in comparison with controls (p<0.05), but not in serum.
CONCLUSIONS:
MS patients have higher levels of intrathecal anti-tau antibodies. Anti-tau antibodies have different avidities in different compartments with the highest values in the CSF of MS patients.
Tangle evolution linked to differential 3- and 4-repeat tau isoform deposition: a double immunofluorolabeling study using two monoclonal antibodies.
Source
Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo, 156-8509, Japan, uchihara-ts@igakuken.or.jp.
Abstract
Double immunofluorolabeling for 3-repeat (3R) and 4-repeat (4R) tau was performed with two monoclonal antibodies, RD3 and RD4, after an additional pretreatment with potassium permanganate and oxalic acid to eliminate nonspecific 3R taucytoplasmic staining. This method involves hyperdilution of one of the primary monoclonal antibodies (≥100-fold), making it undetectable by usual secondary antibodies. The hyperdiluted primary antibody can then only be detected after tyramide amplification. Subsequent application of the other monoclonal antibody at its usual concentration allows double immunofluorolabeling without cross-reaction. This novel method revealed that tau immunoreactivity (IR) in the hippocampal pyramidal neurons of Alzheimer's disease (AD) brains is heterogeneous in that pretangle neurons exhibit 4R-selective (3R-/4R+) IR, ghost tangles exhibit 3R-selective (3R+/4R-) IR, and neurofibrillary tangles exhibit both 3R and 4R (3R+/4R+) IR. Some nigral neurons exhibited RD3 IR in both AD and corticobasal degeneration/progressive supranuclear palsy (CBD/PSP) brains. However, in CBD/PSP cases, 3R IR was always superimposed on 4R IR, while 3R-selective neurons were present in AD cases. These differential isoform profiles may provide a pivotal molecular reference, closely related to the morphological evolution of tau-positive neurons, which may be variable according to disease (CBD/PSP vs. AD), lesion site (cerebral cortex and substantia nigra), or the stage of evolution (from pretangles to ghost tangles). These findings should provide a more comprehensive understanding of the histological differentiation of various tau deposits in human neurodegenerative disease.
Proteomic identification of predictive biomarkers of resistance to neoadjuvant chemotherapy in luminal breast cancer: A possible role for 14-3-3 theta/tau and tBID?
Source
Cancer Biology Proteomics Group, Postgraduate Medical Institute of the University of Hull, Hull, UK.
Abstract
INTRODUCTION:
Chemotherapy resistance is a major obstacle in effective neoadjuvant treatment for estrogen receptor-positive breast cancer. The ability to predict tumour response would allow chemotherapy administration to be directed towards only those patients who would benefit, thus maximising treatment efficiency. We aimed to identify putative protein biomarkers associated with chemotherapy resistance, using fresh tumour samples with antibody microarray analysis and then to perform pilot clinical validation experiments.
MATERIALS AND METHODS:
Chemotherapy resistant and chemotherapy sensitive tumour samples were collected from breast cancer patients who had received anthracycline based neoadjuvant therapy consisting of epirubicin with cyclophosphamide followed by docetaxel. A total of 5 comparative proteomics experiments were performed using invasive ductal carcinomas which demonstrated estrogen receptor positivity (luminal subtype). Protein expression was compared between chemotherapy resistant and chemotherapy sensitive tumour samples using the Panorama XPRESS Profiler725 antibody microarray containing 725 antibodies from a wide variety of cell signalling and apoptosis pathways. A pilot series of archival samples was used for clinical validation of putative predictive biomarkers.
RESULTS:
AbMA analysis revealed 38 differentially expressed proteins which demonstrated at least 1.8 fold difference in expression in chemotherapy resistant tumours and 7 of these proteins (Zyxin, 14-3-3 theta/tau, tBID, Pinin, Bcl-xL, RIP and MyD88) were found in at least 2 experiments. Clinical validation in a pilot series of archival samples revealed 14-3-3 theta/tau and tBID to be significantly associated with chemotherapy resistance.
CONCLUSIONS:
For the first time, antibody microarrays have been used to identify proteins associated with chemotherapy resistance using fresh breast cancer tissue. We propose a potential role for 14-3-3 theta/tau and tBID as predictive biomarkers of neoadjuvant chemotherapy resistance in breast cancer. Further validation in a larger sample series is now required.
Copyright © 2011 Elsevier B.V. All rights reserved.
Defects in the medial entorhinal cortex and dentate gyrus in the mouse model of Sanfilippo syndrome type B.
Source
Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California, United States of America.
Abstract
Sanfilippo syndrome type B (MPS IIIB) is characterized by profound mental retardation in childhood, dementia and death in late adolescence; it is caused by deficiency of α-N-acetylglucosaminidase and resulting lysosomal storage of heparan sulfate. A mouse model, generated by homologous recombination of the Naglu gene, was used to study pathological changes in the brain. We found earlier that neurons in the medial entorhinal cortex (MEC) and the dentate gyrus showed a number of secondary defects, including the presence of hyperphosphorylated tau (Ptau) detected withantibodies raised against Ptau in Alzheimer disease brain. By further use of immunohistochemistry, we now show staining in neurons of the same area for beta amyloid, extending the resemblance to Alzheimer disease. Ptau inclusions in the dentate gyrus of MPS IIIB mice were reduced in number when the mice were administered LiCl, a specific inhibitor of Gsk3β. Additional proteins found elevated in MEC include proteins involved in autophagy and the heparan sulfate proteoglycans, glypicans 1 and 5, the latter closely related to the primary defect. The level of secondary accumulations was associated with elevation of glypican, as seen by comparing brains of mice at different ages or with different mucopolysaccharide storage diseases. The MEC of an MPS IIIA mouse had the same intense immunostaining for glypican 1 and other markers as MPS IIIB, while MEC of MPS I and MPS II mice had weak staining, and MEC of an MPS VI mouse had no staining at all for the same proteins. A considerable amount of glypican was found in MEC of MPS IIIB mice outside of lysosomes. We propose that it is the extralysosomal glypican that would be harmful to neurons, because its heparan sulfate branches could potentiate the formation of Ptau and beta amyloid aggregates, which would be toxic as well as difficult to degrade.
Selective tau tyrosine nitration in non-AD tauopathies.
Source
Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, 60611, USA, juan-reyes@northwestern.edu.
Abstract
Previously, we reported the characterization of two novel antibodies that react with tau nitrated at tyrosine 197 (Tau-nY197) and tyrosine 394 (Tau-nY394) in Alzheimer's disease (AD). In this report, we examined whether tau nitration at these sites also occurs in corticobasal degeneration (CBD), progressive supranuclear palsy (PSP) and Pick's disease (PiD), three neurodegenerative tauopathies that contain abundant tau deposits within glial and neuronal cell types but lack amyloid deposition. The reactivity of these antibodies was also compared to two previously characterizedantibodies Tau-nY18 and Tau-nY29, specific for tau nitrated at tyrosine 18 and tyrosine 29, respectively. In the present experiments, Tau-nY18 did not label the classical pathological lesions of CBD or PSP but did label the neuronal lesions associated with PiD to a limited extent. In contrast, Tau-nY29 revealed some, but not all classes of tau inclusions associated with both CBD and PSP but did label numerous Pick body inclusions in PiD. Tau-nY197 was restricted to the neuropil threads in both CBD and PSP; however, similar to Tau-nY29, extensive Pick body pathology was clearly labeled. Tau-nY394 did not detect any of the lesions associated with these disorders. In contrast, extensive neuronal and glial tau pathology within these diseases was labeled by Tau-Y197, a monoclonal antibody that reacts within the Y-197-containing proline-rich region of the molecule. Based on our Western and IHC experiments, it appears that nitration of tau at tyrosine 29 is a pathological modification that might be associated with neurodegeneration. Collectively, our data suggest that site-specific tau tyrosine nitration events occur in a disease and lesion-specific manner, indicating that nitration appears to be a highly controlled modification in AD and non-AD tauopathies.
GSPE interferes with tau aggregation in vivo: implication for treating tauopathy.
Source
Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA; Alzheimer Disease Research Unit, CIEN Foundation, Queen Sofia Foundation, Madrid, Spain.
Abstract
Tauopathies are characterized by progressive neurodegeneration caused by intracellular accumulation of hyperphosphorylated tau protein aggregates in the brain. The present study was designed to test whether a grape seed polyphenolic extract (GSPE) previously shown to inhibit tau protein aggregation in vitro could benefit tau-mediated neuropathology and behavior deficits in JNPL3 transgenic mice expressing a human tau protein containing the P301L mutation. Nine-month-old JNPL3 mice were treated with GSPE delivered through their drinking water for 6 months. We found that GSPE treatment significantly reduced the number of motor neurons immunoreactive for hyperphosphorylated and conformationally-modified tau in the ventral horns of the spinal cord identified using AT100, PHF-1, AT8, and Alz50tau antibodies. This coincided with a drastically reduced level of hyperphosphorylated and sarcosyl-insoluble tau in spinal cord fractions. Furthermore, the reduction of tau pathology was accompanied by an improvement in the motor function assessed by a wire hang test. Collectively, our results suggest that GSPE can interfere with tau-mediated neurodegenerative mechanisms and ameliorate neurodegenerative phenotype in an animal model of tauopathy. Our studies support further evaluation of GSPE for preventing and/or treating of tauopathies in humans.
Copyright © 2011 Elsevier Inc. All rights reserved.
Association of overexpression of TIF1γ with colorectal carcinogenesis and advanced colorectal adenocarcinoma.
Source
Department of Pathology, New York University School of Medicine, New York, NY 10016, United States.
Abstract
AIM:
To determine the expression and clinical significance of transcriptional intermediary factor 1 gamma (TIF1γ), Smad4 and transforming growth factor-beta (TGFβR) across a spectrum representing colorectal cancer (CRC) development.
METHODS:
Tissue microarrays were prepared from archival paraffin embedded tissue, including 51 colorectal carcinomas, 25 tubular adenomas (TA) and 26 HPs, each with matched normal colonic epithelium. Immunohistochemistry was performed using antibodies against TIF1γ, Smad4 and TGFβRII. The levels of expression were scored semi-quantitatively (score 0-3 or loss and retention for Smad4).
RESULTS:
Overexpression of TIF1γ was detected in 5/26 (19%) HP; however, it was seen in a significantly higher proportion of neoplasms, 15/25 (60%) TAs and 24/51 (47%) CRCs (P < 0.05). Normal colonic mucosa, HP, and TAs showed strong Smad4 expression, while its expression was absent in 22/51 (43%) CRCs. Overexpression of TGFβRII was more commonly seen in neoplasms, 13/25 (52%) TAs and 29/51 (57%) CRCs compared to 9/26 (35%) HP (P < 0.05). Furthermore, there was a correlation between TIF1γ overexpression and Smad4 loss in CRC (Kendall tau rank correlation value = 0.35, P < 0.05). The levels of TIF1γ overexpression were significantly higher in stage III than in stage I and II CRC (P < 0.05).
CONCLUSION:
The findings suggest that over-expression of TIF1γ occurs in early stages of colorectal carcinogenesis, is inversely related with Smad4 loss, and may be a prognostic indicator for poor outcome.
Site directed biotinylation of filamentous phage structural proteins.
Source
Department of Cell Research and Immunology, George S, Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978 Israel. gershoni@tauex.tau.ac.il.
Abstract
ABSTRACT: Filamentous bacteriophages have been used in numerous applications for the display of antibodies and random peptide libraries. Here we describe the introduction of a 13 amino acid sequence LASIFEAQKIEWR (designated BT, which is biotinylated in vivo by E. coli) into the N termini of four of the five structural proteins of the filamentous bacteriophage fd (Proteins 3, 7, 8 and 9). The in vivo and in vitro biotinylation of the various phages were compared. The production of multifunctional phages and their application as affinity reagents are demonstrated.
Dual modification of Alzheimer's disease PHF-tau protein by lysine methylation and ubiquitylation: a mass spectrometry approach.
Source
Greenebaum Cancer Center, University of Maryland, Baltimore, MD, 21201, USA.
Abstract
In sporadic Alzheimer's disease (AD), neurofibrillary lesion formation is preceded by extensive post-translational modification of the microtubule associated protein tau. To identify the modification signature associated with tau lesion formation at single amino acid resolution, immunopurified paired helical filaments were isolated from AD brain and subjected to nanoflow liquid chromatography-tandem mass spectrometry analysis. The resulting spectra identified monomethylation of lysine residues as a new tau modification. The methyl-lysine was distributed among seven residues located in the projection and microtubule binding repeat regions of tau protein, with one site, K254, being a substrate for a competing lysine modification, ubiquitylation. To characterize methyl lysine content in intact tissue, hippocampal sections prepared from post mortem late-stage AD cases were subjected to double-label confocal fluorescence microscopy using anti-tau and anti-methyl lysine antibodies. Anti-methyl lysine immunoreactivity colocalized with 78 ± 13% of neurofibrillary tangles in these specimens. Together these data provide the first evidence that tau in neurofibrillary lesions is post-translationally modified by lysine methylation.
Mechanistic Studies of Antibody-Mediated Clearance of Tau Aggregates Using an ex vivo Brain Slice Model.
Source
Department of Physiology and Neuroscience, New York University School of Medicine New York, NY, USA.
Abstract
Recent studies have shown that immunotherapy clears amyloid beta (Aβ) plaques and reduces Aβ levels in mouse models of Alzheimer's disease (AD), as well as in AD patients. Tangle pathology is also relevant for the neurodegeneration in AD, and our studies have shown that active immunization with an AD related phospho-tau peptide reduces aggregated tau within the brain and slows the progression of tauopathy-induced behavioral impairments. Thus, clearance of neurofibrillary tangles and/or their precursors may reduce synaptic and neuronal loss associated with AD and other tauopathies. So far the mechanisms involved in antibody-mediated clearance of tau pathology are yet to be elucidated. In this study we have used a mouse brain slice model to examine the uptake and localization of FITC labeled anti-tau antibodies. Confocal microscopy analysis showed that the FITC labeled anti-tau antibody co-stained with phosphorylated tau, had a perinuclear appearance and co-localized with markers of the endosomal/lysosomal pathway. Additionally, tau and FITC-IgG were found together in an enriched lysosome fraction. In summary, antibody-mediated clearance of intracellular tau aggregates appears to occur via the lysosomal pathway.
A proteomic study identifies different levels of light chain ferritin in corticobasal degeneration and progressive supranuclear palsy.
Source
Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.
Abstract
Clinical and pathological evidence supports the notion that corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) are distinct, but overlapping neurodegenerative tauopathies. Although both disorders are characterized by abnormal accumulation of 4-repeat tau, they display distinct proteolytic profiles of tau species and they have distinct astrocytic lesions, astrocytic plaques in CBD and tufted astrocytes in PSP. To investigate other differences between these two disorders at the molecular level, we compared the profiles of proteins from caudate nucleus of CBD and PSP by quantitative two-dimensional difference gel electrophoresis. Twenty-one protein spots differentially expressed in CBD and PSP were dissected for mass spectrometry (MS). One of the spots was identified by MS to contain light chain (LC) ferritin. Western blot analysis verified the presence of LC ferritin in this spot and showed that this protein was two-fold higher in caudate of CBD than that of PSP samples. These results were confirmed by LC ferritin immunohistochemistry. Co-labeling of caudate nucleus with tau and LC ferritin antibodies showed the presence of LC ferritin immunoreactivity in astrocytic plaques of CBD, but minimal labeling of tufted astrocytes in PSP. This difference did not reflect the extent of gliosis. Analysis of other brain regions in CBD and PSP showed no difference in LC ferritin levels. Together the data suggest that LC ferritin is a unique marker of astrocytic lesions in CBD, adding further support to the notion that CBD and PSP are distinct clinicopathologic entities.
Transglutaminase 1 and its regulator tazarotene-induced gene 3 localize to neuronal tau inclusions in tauopathies.
Source
Department of Anatomy and Neurosciences, Neuroscience Campus Amsterdam, VU University Medical Center, The Netherlands. m.wilhelmus@vumc.nl
Abstract
Alzheimer's disease (AD), progressive supranuclear palsy (PSP), frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17), and Pick's disease (PiD) are commonly known as tauopathies. Neurodegeneration observed in these diseases is linked to neuronal fibrillary hyperphosphorylated tau protein inclusions. Transglutaminases (TGs) are inducible enzymes, capable of modifying conformational and/or structural properties of proteins by inducing molecular cross-links. Both transglutaminase 1 (TG1) and transglutaminase 2 (TG2) are abundantly expressed in the brain and are associated with fibrillary hyperphosphorylated tau protein inclusions in neurons of AD, so-called neurofibrillary tangles (NFTs). However, other data obtained by our group suggested that tau pathology in the brain may be primarily related to TG1 and not to TG2 activity. To obtain more information on this issue, we set out to investigate the association of TG1, TG2, and TG-catalysed cross-links with fibrillary hyperphosphorylated tau inclusions in tauopathies other than AD, using immunohistochemistry. We found strong TG1 and TG-catalysed cross-link staining in neuronal tau inclusions characteristic of PSP, FTDP-17 with mutations in the tau gene (FTDP-17T), and PiD brain, whereas, in contrast to AD, TG2 was only rarely observed in these inclusions. Furthermore, using a biochemical approach, we demonstrated that tau is a substrate for TG1-mediated cross-linking. Interestingly, we found co-localization of the TG1 activator, tazarotene-induced gene 3 (TIG3), in the neuronal tau inclusions of PSP, FTDP-17T, and PiD, but not in NFTs of AD cases, indicating that these tau-containing protein aggregates are not identical. We conclude that TG1-catalysed cross-linking, regulated by TIG3, might play an important role in the formation of neuronaltau inclusions in PSP, FTDP-17T, and PiD brain.
Copyright © 2011 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Experimental Research On Nitric Oxide And The Therapy Of Alzheimer Disease: A Challenging Bridge.
Source
Institute of Pharmacology, Catholic University School of Medicine, Largo Francesco Vito, 1 00168 Rome, Italy. cmancuso@rm.unicatt.it.
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by severe cognitive impairment due to neuronal death. Although the lost of cognitive function is the main problem for AD subjects, death occurs due to secondary issues such as concomitant infections, respiratory complications or multi-organ failure. Current drugs used in AD are acetylcholinesterase inhibitors and antagonists of the N-methyl-D-aspartate receptor. These drugs may only slightly improve cognitive functions but have only very limited impact on the clinical course of the disease. Over the last 5 years, new targets were identified and innovative drugs against AD have been designed and developed. Worthy of mention are beta-secretase inhibitors, monoclonal antibodies against amyloid-beta-peptide and tau inhibitors. However, although promising beneficial effects were highlighted in the data from preclinical studies, only few of these new drugs improved cognitive functions for a significant time frame in AD subjects. Controversial is the therapeutic effect on AD obtained through the manipulation of the nitric oxide synthase/nitric oxide system since the potential toxic effects on brain function could overcome the beneficial effects. The aim of this review is to analyze from a pharmacologic point of view both old and new drugs developed for the treatment of AD. In addition, the risk/benefit ratio related to the modulation of the nitric oxide synthase/nitric oxide system in AD brain will be analyzed.
- PMID:
- 21999733
- [PubMed - as supplied by publisher]
Novel Antibody Capture Assay for Paraffin-Embedded Tissue Detects Wide-Ranging Amyloid Beta and Paired Helical Filament-Tau Accumulation in Cognitively Normal Older Adults.
Source
Departments of Pathology Medicine Neurology, University of Washington Geriatric Research Clinical and Education Center, VA-Puget Sound Health Care System Group Health Research Institute, Group Health Cooperative, Seattle, Wa.
Abstract
Quantifying antigens in formalin-fixed tissue is challenging and limits investigation in population-based studies of brain aging. To address this major limitation, we have developed a new technique that we call "Histelide": immunohistochemistry (HIST-) and enzyme-linked immunosorbent assay (ELISA) (-EL-) performed on a glass slide (-IDE). We validated Histelide in sections of prefrontal cortex from 20 selected cases: 12 subjects with clinically and neuropathologically diagnosed Alzheimer's disease (AD), either autosomal dominant or late-onset forms, and 8 clinical and neuropathologic controls. AD cases had significantly increased amyloid beta (Aβ) peptide and paired helical filament- (PHF-) tau per area of neocortex that was proteinase K-sensitive, and significantly decreased amount of synaptophysin. We next investigated prefrontal cortex from 81 consecutive cases of high-cognitive performers from the Adult Changes in Thought (ACT) study, a population-based study of brain aging and incident dementia. As expected, latent AD was common in this group; however, our results quantified widely individually varying levels of Aβ peptides and PHF-tau among these high-cognitive performers. This novel approach obtains quantitative data from population-based studies, and our initial studies with high-cognitive performers provide important quantitative insights into latent AD that should help guide expectations from neuroimaging and prevention studies.
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