Earlier diagnosis and treatment of Alzheimer’s disease would greatly benefit from the identification of biomarkers at the prodromal stage. Using a prominent animal model of aspects of the disease, we here show using clinically relevant methodologies that very young, pre-pathological PDAPP mice, which overexpress mutant human amyloid precursor protein in the brain, exhibit two cryptic deficits that are normally undetected using standard methods of assessment. Despite learning a spatial memory task normally and displaying normal brain glucose uptake, they display faster forgetting after a long delay following performance to a criterion, together with a strong impairment of brain glucose uptake at the time of attempted memory retrieval. Preliminary observations suggest that these deficits, likely caused by an impairment in systems consolidation, could be rescued by immunotherapy with an anti-β-amyloid antibody. Our data suggest a biomarker strategy for the early detection of β-amyloid-related abnormalities.

The authors report a patient with Alzheimer disease (AD) without encephalitis who was immunized with AN-1792 (an adjuvanted formulation of Abeta-42). There were no amyloid plaques in the frontal cortex and abundant Abeta-immunoreactive macrophages, but tangles and amyloid angiopathy were present. The white matter appeared normal and minimal lymphocytic infiltration in the leptomeninges was observed. This case illustrates the effects of an Abeta-based immunization on AD pathogenesis in the absence of overt meningoencephalitis and leukoencephalopathy.

Serum samples from Alzheimer's disease (AD) patients immunized with Abeta42 (AN1792) were analyzed to determine the induced antibody properties including precise amyloid-beta peptide (Abeta) epitopes and amyloid plaque-binding characteristics. The predominant response in these patients is independent of whether or not meningoencephalitis developed and is against the free amino terminus of Abeta. The immunostaining of amyloid plaques in brain tissue by patient sera is adsorbable by a linear Abeta1-8 peptide, demonstrating that the antibodies are directed predominantly to this epitope and not dependent on Abeta conformations or aggregates specific to plaques. Furthermore, the antibodies are not capable of binding amyloid precursor protein and would be predicted to be competent in facilitating clearance of amyloid plaques in AD brains.

The actin cytoskeleton is essential for osteoclasts main function, bone resorption. Two different organizations of actin have been described in osteoclasts, the podosomes belt corresponding to numerous F-actin columns arranged at the cell periphery, and the sealing zone defined as a unique large band of actin. To compare the role of these two different actin organizations, we imaged osteoclasts on various substrata: glass, dentin, and apatite. Using primary osteoclasts expressing GFP-actin, we found that podosome belts and sealing zones, both very dynamic actin structures, were present in mature osteoclasts; podosome belts were observed only in spread osteoclasts adhering onto glass, whereas sealing zone were seen in apico-basal polarized osteoclasts adherent on mineralized matrix. Dynamic observations of several resorption cycles of osteoclasts seeded on apatite revealed that 1) podosomes do not fuse together to form the sealing zone; 2) osteoclasts alternate successive stationary polarized resorption phases with a sealing zone and migration, nonresorption phases without any specific actin structure; and 3) apatite itself promotes sealing zone formation though c-src and Rho signaling. Finally, our work suggests that apatite-mediated sealing zone formation is dependent on both c-src and Rho whereas apico-basal polarization requires only Rho.

Supercritical fluid extraction (SFE) with and without entrainer combined with organic solvent extraction was used for fractionation of bioactive natural products as alkaloids and antioxidants from cat's claw (Uncaria tomentosa (Willd.) DC.) bark. Extracts obtained from this plant have a number of beneficial effects, including anti-inflammatory or immune stimulator. The aim of this work was to obtain extracts of enriched and limited alkaloid concentrations, good antioxidants and tannin agents. The results demonstrated that a hybrid process involving SFE is a selective method to obtain an oxindole alkaloid rich fraction (186.0 ± 3.2 mg total pentacyclic oxindole alkaloids/g extract) and a product enriched in tannins (23.8 ± 1.9% tannin content in extract) and antioxidants (IC50 = 5.88 ± 0.54 μg/ml extract).

Transgenic mice mimicking certain features of Alzheimer's disease (AD)-pathology, namely amyloid plaques and neurofibrillary tangles, have been developed in an effort to better understand the mechanism leading to the formation of these characteristic cerebral lesions. More recently, these animal models have been widely used to investigate emergent therapies aimed at the reduction of the cerebral amyloid load. Several studies have shown that immunotherapy targeting the amyloid peptide (Abeta) is efficacious at clearing the amyloid plaques or preventing their formation, and at reducing the memory/behavior impairment observed in these animals. In AD, different types of plaques likely have different pathogenic significance, and further characterization of plaque pathology in the PDAPP transgenic mice would enhance the evaluation of potential therapeutics. In the present study, a morphological classification of amyloid plaques present in the brains of PDAPP mice was established by using Thioflavin-S staining. Neuritic dystrophy associated with amyloid plaques was also investigated. Finally, the efficacy of passive immunization with anti-Abeta antibodies on the clearance of Thio-S positive amyloid plaques was studied. Our results show that distinct morphological types of plaques are differentially cleared depending upon the isotype of the antibody.

In transgenic mouse models of Alzheimer’s disease (AD), immunization with beta-amyloid peptide Aβ1–42 slows or reverses disease progression and provides neuronal protection and improvement in memory tasks. Development of a safe and effective immunization strategy for therapeutic use requires an understanding of the immune system components involved in these responses. A key discovery has been that reduction of AD-like neuropathologies can be obtained with passive administration of antibodies, and that a T cell response against Aβ is not required. Several mechanisms have been suggested to be involved in efficacy, including antibody Fc-mediated and Fc-independent events; these mechanisms are reviewed here.

Podosomes, small actin-based adhesion structures, differ from focal adhesions in two aspects: their core structure and their ability to organize into large patterns in osteoclasts. To address the mechanisms underlying these features, we imaged live preosteoclasts expressing green fluorescent protein-actin during their differentiation. We observe that podosomes always form inside or close to podosome groups, which are surrounded by an actin cloud. Fluorescence recovery after photobleaching shows that actin turns over in individual podosomes in contrast to cortactin, suggesting a continuous actin polymerization in the podosome core. The observation of podosome assemblies during osteoclast differentiation reveals that they evolve from simple clusters into rings that expand by the continuous formation of new podosomes at their outer ridge and inhibition of podosome formation inside the rings. This self-organization of podosomes into dynamic rings is the mechanism that drives podosomes at the periphery of the cell in large circular patterns. We also show that an additional step of differentiation, requiring microtubule integrity, stabilizes the podosome circles at the cell periphery to form the characteristic podosome belt pattern of mature osteoclasts. These results therefore provide a mechanism for the patterning of podosomes in osteoclasts and reveal a turnover of actin inside the podosome.

Transgenic PDAPP mice, which express a disease-linked isoform of the human amyloid precursor protein, exhibit CNS pathology that is similar to Alzheimer's disease. In an age-dependent fashion, the mice develop plaques containing beta-amyloid peptide (Abeta) and exhibit neuronal dystrophy and synaptic loss. It has been shown in previous studies that pathology can be prevented and even reversed by immunization of the mice with the Abeta peptide. Similar protection could be achieved by passive administration of some but not all monoclonal antibodies against Abeta. In the current studies we sought to define the optimal antibody response for reducing neuropathology. Immune sera with reactivity against different Abeta epitopes and monoclonal antibodies with different isotypes were examined for efficacy both ex vivo and in vivo. The studies showed that: (i) of the purified or elicited antibodies tested, only antibodies against the N-terminal regions of Abeta were able to invoke plaque clearance; (ii) plaque binding correlated with a clearance response and neuronal protection, whereas the ability of antibodies to capture soluble Abeta was not necessarily correlated with efficacy; (iii) the isotype of the antibody dramatically influenced the degree of plaque clearance and neuronal protection; (iv) high affinity of the antibody for Fc receptors on microglial cells seemed more important than high affinity for Abeta itself; and (v) complement activation was not required for plaque clearance. These results indicate that antibody Fc-mediated plaque clearance is a highly efficient and effective process for protection against neuropathology in an animal model of Alzheimer's disease.

Cbl is an adaptor protein that is phosphorylated and recruited to several receptor and non-receptor tyrosine kinases upon their activation. After binding to the activated receptor, Cbl plays a key role as a kinase inhibitor and as an E3 ubiquitin ligase, thereby contributing to receptor down-regulation and internalization. In addition, Cbl translocates to intracellular vesicular compartments following receptor activation. We report here that Cbl also associates with Golgi membranes. Confocal immunofluorescence staining of Cbl in a variety of unstimulated cells, including CHO cells, revealed a prominent perinuclear colocalization of Cbl and a Golgi marker. Both the prominent Cbl staining and the Golgi marker were dispersed by brefeldin A. Subcellular fractionation of CHO cells demonstrated that about 10% of Cbl is stably associated with membranes, and that Golgi-enriched membrane fractions produced by isopycnic density centrifugation and free-flow electrophoresis are also enriched in Cbl, relative to other membrane fractions. The membrane-bound Cbl was hyperphosphorylated and it co-immunoprecipitated with endogenous Src. By immunofluorescence, some Src colocalized with Cbl and Golgi markers, and Src, like Cbl, was present in the Golgi-enriched fraction prepared by sequential density centrifugation and free-flow electrophoresis. Transfection of an activated form of Src, but not wild-type Src, increased the amount of Src that co-immunoprecipitated with Cbl, and increased the intensity of Cbl staining on the Golgi. This result, together with the increased tyrosine phosphorylation of the membrane-associated Cbl, suggests that Golgi-associated Cbl could be part of a molecular complex that contains activated Src. The localization and interaction of Src and Cbl at the Golgi and the regulation of the interaction of Cbl with Golgi membrane suggest that this complex may contribute to the regulation of Golgi function.

In AD certain brain structures contain a pathological density of A beta protein deposited into plaques. The effect of genetic mutations found in early onset AD patients was an overproduction of A beta 42, strongly suggesting that overproduction of A beta 42 is associated with AD. We hypothesized that an immunological response to A beta 42 might alter its turnover and metabolism. Young PDAPP transgenic mice were immunized with A beta 1-42, which essentially prevented amyloid deposition; astrocytosis was dramatically reduced and there was reduction in A beta-induced inflammatory response as well. A beta 1-42 immunization also appeared to arrest the progression of amyloidosis in older PDAPP mice. A beta immunization appears to increase clearance of amyloid plaques, and may therefore be a novel and effective approach for the treatment of AD.

Biology of the CellVolume 91, Issue 7 p. 563-563 Vesicular trafficking of p130Cas Frédénic Bard, Frédénic Bard Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this authorRoland Baron, Roland Baron Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this authorPierre Jurdic, Pierre Jurdic Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this author Frédénic Bard, Frédénic Bard Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this authorRoland Baron, Roland Baron Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this authorPierre Jurdic, Pierre Jurdic Dpts of Cell Biology and Orthopoedics, School of Medecine, Yale U., New-Haven, CT 06510 USA — Ecole Normale Supérieure de Lyon, 46 allée d'Italie, 69007 LYON, FranceSearch for more papers by this author First published: 01 February 2012 https://doi.org/10.1016/S0248-4900(99)90294-0Citations: 1AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume91, Issue7September 1999Pages 563-563 RelatedInformation