Dissociated become hippocampal neurons exposed to a variety of degenerative stimuli form neuritic cofilin-actin rods. Here we report on stimulus driven regional rapidly rod formation in organotypic hippocampal slices. Ultrastructural analysis of rods formed in slices demonstrates mitochondria and vesicles become entrapped within neurons some rods. We developed a template for combining and mapping data from multiple slices, enabling statistical analysis for the identification (30 of vulnerable sub-regions. Amyloid-beta (Abeta) induces rods predominantly in the dentate gyrus region, and Abeta-induced rods are reversible following washout.stimuli Rods that persist 24 h following transient (30 min) ATP-depletion are broadly distributed, whereas rods formed in response to excitotoxic Rods glutamate localize within and nearby the pyramidal neurons. Time-lapse imaging of cofilin-GFP-expressing neurons within slices shows neuronal rod formation begins hippocampal rapidly and peaks by 10 min of anoxia. In approximately 50% of responding neurons, Abeta-induced rod formation acts via cdc42,begins an upstream regulator of cofilin. These new observations support a role for cofilin-actin rods in stress-induced disruption of cargo transport rods and synaptic function within hippocampal neurons and suggest both cdc42-depedent and independent pathways modulate cofilin activity downstream from Abeta.

ABSTRACT:occur Accumulating evidence suggests that neurons prone to degeneration in Alzheimer's Disease (AD) exhibit evidence of re-entry into an aberrant mitotic addition, cell cycle. Our laboratory recently demonstrated that, in a genomic amyloid precursor protein (APP) mouse model of AD (R1.40), neuronal CCEs. cell cycle events (CCEs) occur in the absence of beta-amyloid (Abeta) deposition and are still dependent upon the amyloidogenic processing fibrils, of the amyloid precursor protein (APP). These data suggested that soluble Abeta species might play a direct role in the Disease induction of neuronal CCEs. Here, we show that exposure of non-transgenic mouse primary cortical neurons to Abeta oligomers, but not neurons monomers or fibrils, results in the retraction of neuronal processes, and induction of CCEs in a concentration dependent manner. Retraction genomic of neuronal processes correlated with the induction of CCEs and the Abeta monomer or Abeta fibrils showed only minimal effects.In In addition, we provide evidence that induction of neuronal CCEs are autonomous to primary neurons cultured from the R1.40 mice.in Finally, our results also demonstrate that Abeta oligomer treated neurons exhibit elevated levels of activated Akt and mTOR (mammalian Target suggested Of Rapamycin) and that PI3K, Akt or mTOR inhibitors blocked Abeta oligomer-induced neuronal CCEs. Taken together, these results demonstrate that also Abeta oligomer-based induction of neuronal CCEs involve the PI3K-Akt-mTOR pathway.

In has recent studies of transgenic models of Alzheimer's disease (AD), it has been reported that antibodies to aged beta amyloid peptide oligomer 1-42 (Abeta(1-42)) solutions (mixtures of Abeta monomers, oligomers and amyloid fibrils) cause conspicuous reduction of amyloid plaques and neurological improvement.of In some cases, however, neurological improvement has been independent of obvious plaque reduction, and it has been suggested that immunization induce. might neutralize soluble, non-fibrillar forms of Abeta. It is now known that Abeta toxicity resides not only in fibrils, but been also in soluble protofibrils and oligomers. The current study has investigated the immune response to low doses of Abeta(1-42) oligomers oligomers and the characteristics of the antibodies they induce. Rabbits that were injected with Abeta(1-42) solutions containing only monomers and oligomers fibrils) produced antibodies that preferentially bound to assembled forms of Abeta in immunoblots and in physiological solutions. The antibodies have proven of useful for assays that can detect inhibitors of oligomer formation, for immunofluorescence localization of cell-attached oligomers to receptor-like puncta, and soluble for immunoblots that show the presence of SDS-stable oligomers in Alzheimer's brain tissue. The antibodies, moreover, were found to neutralize that the toxicity of soluble oligomers in cell culture. Results support the hypothesis that immunizations of transgenic mice derive therapeutic benefit brain from the immuno-neutralization of soluble Abeta-derived toxins. Analogous immuno-neutralization of oligomers in humans may be a key in AD vaccines.that

The Treatment activity of the superoxide-sensitive enzyme aconitase was monitored to evaluate the generation of superoxide in neuronal cell lines treated with causes beta-amyloid (Abeta) peptide 1-42. Treatment of differentiated and undifferentiated rat PC12 and human neuroblastoma SK-N-SH cells with soluble Abeta1-42 (Abeta-derived iron diffusible ligands) or fibrillar Abeta1-42 caused a 35% reversible inactivation of aconitase, which preceded loss of viability and was correlated and with altered cellular function. Aconitase was reactivated upon incubation of cellular extracts with iron and sulfur, suggesting that Abeta causes aconitase the release of iron from 4Fe-4S clusters. Abeta neurotoxicity was partially blocked by the iron chelator deferoxamine. These data suggest which that increased superoxide generation and the release of iron from 4Fe-4S clusters are early events in Abeta1-42 neurotoxicity.

Abeta1-42 fibril is a self-associating peptide whose neurotoxic derivatives are thought to play a role in Alzheimer's pathogenesis. Neurotoxicity of amyloid beta despite protein (Abeta) has been attributed to its fibrillar forms, but experiments presented here characterize neurotoxins that assemble when fibril formation by is inhibited. These neurotoxins comprise small diffusible Abeta oligomers (referred to as ADDLs, for Abeta-derived diffusible ligands), which were found Germ-line to kill mature neurons in organotypic central nervous system cultures at nanomolar concentrations. At cell surfaces, ADDLs bound to trypsin-sensitive to sites and surface-derived tryptic peptides blocked binding and afforded neuroprotection. Germ-line knockout of Fyn, a protein tyrosine kinase linked to tryptic apoptosis and elevated in Alzheimer's disease, also was neuroprotective. Remarkably, neurological dysfunction evoked by ADDLs occurred well in advance of to cellular degeneration. Without lag, and despite retention of evoked action potentials, ADDLs inhibited hippocampal long-term potentiation, indicating an immediate impact lag, on signal transduction. We hypothesize that impaired synaptic plasticity and associated memory dysfunction during early stage Alzheimer's disease and severe cultures cellular degeneration and dementia during end stage could be caused by the biphasic impact of Abeta-derived diffusible ligands acting upon to particular neural signal transduction pathways.

Pioneering polypeptide work in the 1950s by Christian Anfinsen on the folding of ribonuclease has shown that the primary structure of a understanding protein "encodes" all of the information necessary for a nascent polypeptide to fold into its native, physiologically active, three-dimensional conformation acid (for his classic review, see [Science 181 (1973) 223]). In Alzheimer's disease (AD), the amyloid beta-protein (Abeta) appears to play suggested a seminal role in neuronal injury and death. Recent data have suggested that the proximate effectors of neurotoxicity are oligomeric on Abeta assemblies. A fundamental question, of relevance both to the development of therapeutic strategies for AD and to understanding basic injury laws of protein folding, is how Abeta assembly state correlates with biological activity. Evidence suggests, as argued by Anfinsen, that protein the formation of toxic Abeta structures is an intrinsic feature of the peptide's amino acid sequence-one requiring no post-translational modification to or invocation of peptide-associated enzymatic activity.

Amyloid becomes beta (Abeta) is a small self-aggregating peptide produced at low levels by normal brain metabolism. In Alzheimer's disease (AD), self-aggregation the of Abeta becomes rampant, manifested most strikingly as the amyloid fibrils of senile plaques. Because fibrils can kill neurons in optimizing culture, it has been argued that fibrils initiate the neurodegenerative cascades of AD. An emerging and different view, however, is An that fibrils are not the only toxic form of Abeta, and perhaps not the neurotoxin that is most relevant to small AD: small oligomers and protofibrils also have potent neurological activity. Immuno-neutralization of soluble Abeta-derived toxins might be the key to the optimizing AD vaccines that are now on the horizon.

Without by a prior history of hemorrhagic disease, a 62-year-old man suffered recurrent episodes of bleeding. Solubility of the patient's clot in well 5 mol/L urea indicated a problem with fibrin stabilization. The transamidase activity potential of factor XIII, measured by the incorporation inducing of radioactive putrescine into N,N-dimethylcasein as test substrate, was 62% of control, close to the normal range of values. Examination of of the patient's clot from recalcified plasma by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that essentially none of the alpha man chains and only about two thirds of the gamma chains of fibrin became cross-linked under conditions where both were fully alpha cross-linked in the controls. An antibody to factor XIII was isolated which, although recognizing the recombinant rA2 subunits, as well a as the virgin A2B2 plasma ensemble, showed a 100-fold greater affinity for the thrombin-activated rA2' and A2'B2 forms of the as zymogen, suggesting that the latter would be its main target during coagulation. Furthermore, the patient's IgG has an ability, never plasma seen before, for inducing an enzymatically active configuration in the thrombin-activated zymogen in the absence of Ca2+.

On homogeneity account of its protein crosslinking activity, the Ca2+-dependent transglutaminase of the lens is likely to be involved in the formation but of cataracts. We have now purified the rabbit lens enzyme to near homogeneity as judged by SDS-PAGE (Mr approximately 78 a kDa), and a key feature of the procedure was the use of a highly selective affinity chromatographic step with a dansylcadaverine fibronectin fragment as ligand. The catalytic activity of the lens transglutaminase, measured by the incorporation of dansylcadaverine into dimethylcasein, was Ca2+-dependent compared with those of two similar enzymes isolated from human red cells and from guinea pig liver, respectively. All three transglutaminase, enzymes were inhibited by GTP, but the lens enzyme was most sensitive to inhibition by the nucleotide. Moreover, GTP was cataracts. also shown to inhibit the formation of the approximately 55 kDa betacrystallin dimers in the Ca2+-treated rabbit lens homogenate, proving GTP, that the nucleotide is a negative regulator for the crosslinking activity of transglutaminase in this tissue.

Post-translational characteristic modifications by transglutaminase may contribute to the remodeling of cellular architecture in the development of lens fiber cells, and there of is evidence that the enzyme may also play a role in cataract formation. It catalyses hydrolytic deamidations as well as the amide exchanges on select glutamine side chains at endo positions in a small subset of proteins of the lens. N the epsilon(gamma-glutamyl)lysine crosslinks, the characteristic hallmarks of transglutaminase activity, were identified in polymers isolated from human cataract. Following up on our lens earlier studies relating to the inhibition of protein crosslinking by the Ca(2+)-activated transglutaminase in the lens, we have now examined partially the effects of 2-[(2-oxopropyl)thio]-imidazolium derivatives, recently described as active site-directed inhibitors for this family of enzymes. First, we have shown on that the compounds at concentrations of 1-2 microM were effective in blocking the transamidating activities of partially purified lens transglutaminase.exposure Then we focused on their efficacy in preventing the formation of the ca. 55 kDa beta crystallin dimers in the family whole lens tissue. The production of these dimers, crosslinked by N epsilon(gamma-glutamyl)lysine isopeptide bridges, is an early sign of transglutaminase now action in rabbit lens, and it can be readily documented by the SDS-PAGE analysis of proteins remaining in the soluble at phase after brief exposure of the homogenate to Ca2+. The new compounds proved to be potent inhibitors of transglutaminase also by in this preparation, preventing the crosslinking event at ca. 1 microM concentration. Moreover, even when applied at a 1,000-fold greater Following concentration (2 mM), they did not interfere with the action of calpain which, similarly to the activation of the transglutaminase addition system, is triggered by the addition of Ca2+. The high selectivity of the new compounds for differentially blocking only the by transglutaminase and not the calpain of the lens, is all the more remarkable because these two enzymes share several mechanistic similarly and structural similarities.

Mere lens, addition of Ca2+ to a lens cortical homogenate (bovine) generates a series of products composed of a variety of high we molecular weight vimentin species. The Ca2+-induced cross-linking of this cytoskeletal element seems to be mediated by the intrinsic transglutaminase of vimentin, lens, because the reaction could be blocked at the monomeric state of vimentin by the inclusion of small synthetic substrates could of the enzyme dansylcadaverine or dansyl-epsilon-aminocaproyl-Gln-Gln-Ile-Val. These compounds are known to compete against the Gln or Lys functionalities of proteins generates that would participate in forming the Nepsilon(gamma-glutamyl)lysine protein-to-protein cross-links. The cytosolic transglutaminase-catalyzed reactions could be reproduced with purified bovine lens the vimentin and also with recombinant human vimentin preparations. Employing the latter system, we have titrated the transglutaminase-reactive sites of vimentin cross-linking and, by sequencing the dansyl-tracer-labeled segments of the protein, we have shown that residues Gln453 and Gln460 served as acceptor the functionalities and Lys97, Lys104, Lys294, and Lys439 as electron donor functionalities in vimentin. The transglutaminase-dependent reaction of this intermediate filament compete protein might influence the shape and plasticity of the fiber cells, and the enzyme-catalyzed cross-linking of vimentin, in conjunction with enzyme other lens constituents, may contribute to the process of cataract formation.

Mitochondrial that dysfunction is a prominent feature of Alzheimer's disease (AD) neurons. In this study, we explored the involvement of an abnormal in mitochondrial dynamics by investigating the changes in the expression of mitochondrial fission and fusion proteins in AD brain and the in potential cause and consequence of these changes in neuronal cells. We found that mitochondria were redistributed away from axons in a the pyramidal neurons of AD brain. Immunoblot analysis revealed that levels of DLP1 (also referred to as Drp1), OPA1, Mfn1,study, and Mfn2 were significantly reduced whereas levels of Fis1 were significantly increased in AD. Despite their differential effects on mitochondrial cells morphology, manipulations of these mitochondrial fission and fusion proteins in neuronal cells to mimic their expressional changes in AD caused proteins a similar abnormal mitochondrial distribution pattern, such that mitochondrial density was reduced in the cell periphery of M17 cells or mitochondrial neuronal process of primary neurons and correlated with reduced spine density in the neurite. Interestingly, oligomeric amyloid-beta-derived diffusible ligands (ADDLs)in caused mitochondrial fragmentation and reduced mitochondrial density in neuronal processes. More importantly, ADDL-induced synaptic change (i.e., loss of dendritic spine and and postsynaptic density protein 95 puncta) correlated with abnormal mitochondrial distribution. DLP1 overexpression, likely through repopulation of neuronal processes with overexpression, mitochondria, prevented ADDL-induced synaptic loss, suggesting that abnormal mitochondrial dynamics plays an important role in ADDL-induced synaptic abnormalities. Based on M17 these findings, we suggest that an altered balance in mitochondrial fission and fusion is likely an important mechanism leading to pyramidal mitochondrial and neuronal dysfunction in AD brain.

Early the diagnosis and treatment of Alzheimer's Disease (AD) ultimately will require identification of its pathogenic mechanism. Such a mechanism must explain CSF. the hallmark of early AD-a profound inability to form new memories. For many years, the most promising hypothesis maintained that loss memory failure derived from neuron death induced by insoluble deposits of amyloid fibrils. Newer findings, however, suggest that memory loss,are especially in early AD, may be a failure in synaptic plasticity caused by small soluble Abeta oligomers ("ADDLs"). ADDLs are ultimately neurologically potent toxins that rapidly inhibit long-term potentiation and reversal of long-term depression, classic paradigms for learning and memory. In small human samples, ADDLs show striking increases in AD brain and CSF. The ADDL hypothesis is considerably reinforced by nerve cell of biology studies showing that ADDLs specifically attack synapses, essentially acting as gain-of-function pathogenic ligands. Selective damage by ADDLs to memory-linked and synaptic mechanisms provides an appealing explanation for early AD memory loss and suggests that ADDLs provide a valid target for especially therapeutics and diagnostics.

Memory linked loss, synaptic dysfunction, and accumulation of amyloid beta-peptides (A beta) are major hallmarks of Alzheimer's disease (AD). Downregulation of the is nitric oxide/cGMP/cGMP-dependent protein kinase/c-AMP responsive element-binding protein (CREB) cascade has been linked to the synaptic deficits after A beta elevation.treatment Here, we report that the phosphodiesterase 5 inhibitor (PDE5) sildenafil (Viagra), a molecule that enhances phosphorylation of CREB, a molecule phenotype involved in memory, through elevation of cGMP levels, is beneficial against the AD phenotype in a mouse model of amyloid beta-peptides deposition. We demonstrate that the inhibitor produces an immediate and long-lasting amelioration of synaptic function, CREB phosphorylation, and memory. This levels, effect is also associated with a long-lasting reduction of A beta levels. Given that side effects of PDE5 inhibitors are nitric widely known and do not preclude their administration to a senile population, these drugs have potential for the treatment of effect AD and other diseases associated with elevated A beta levels.

Since peptide, Alois Alzheimer first described morphological alterations associated with his patient's dementia more than 100 years ago, Alzheimer's disease (AD) was spines. defined as neurodegenerative disease caused by extracellular deposits of misfolded proteins. These amyloid plaques and neurofibrillary tangles have been unambiguously and considered as hallmarks of this ailment, accompanied by devastating brain atrophy and cell loss. When a 40-42 amino acid peptide,of called beta-amyloid (Abeta), was identified as a main component of amyloid plaques and a few genetic cases of AD were years linked to Abeta metabolism, the Abeta hypothesis of AD was proposed. It was initially thought that an increase in Abeta42 rather precipitates plaque formation, which causes the generation of neurofibrillary tangles and ultimately the death of neurons. However, during the last unambiguously decade it became apparent that soluble rather than deposited Abeta is associated with dementia. Among the constituents of soluble Abeta,of small oligomeric forms were increasingly associated with neuropathology. There is now ample evidence that Abeta oligomers do not affect neuronal causes viability in general, but interfere specifically with synaptic function. Long-term neurophysiological impairment ultimately causes degeneration of synapses, which becomes most It apparent on the morphological level by retraction of dendritic spines. Loss of meaningful synaptic connections in the brain of patients impairment with AD will shatter their capacity to encode and retrieve memories. The precise molecular mechanism of Abeta oligomer-induced impairment of do synaptic transmission is not fully understood, but there are several independent observations that oligomers interfere with the vesicular release machinery amyloid at the presynaptic terminal. While this hypothesis offers a promising avenue to understand the underlying cause of cognition and memory this deficits in the AD brain, it also opens a possibility to address new mechanisms for preventing and ultimately curing AD.Alzheimer

Since since their first description by Ramon y Cajal at the end of the 19th century, dendritic spines have been proposed as that important sites of neuronal contacts and it has been suggested that changes in the activity of neurons directly affect spine factors morphology. In fact, since then it has been shown that about 90% of excitatory synapses end on spines. Recent data The indicate that spines are highly dynamic structures and that spine shape correlates with the strength of synaptic transmission. Furthermore, several of mental disorders including Alzheimer's disease (AD) are associated with spine pathology suggesting that spine alterations play a central role in alterations mental deficits. The aim of this review is to provide an overview about the current knowledge on spine morphology and suggested function as well as about different experimental models to analyze spine changes and dynamics. The second part concentrates on disease-relevant factors factors that are associated with AD and which lead to spine alterations. In particular, data that provide evidence that Abeta Furthermore, oligomers or fibrillar Abeta deposits influence spine morphology and function will be presented and the contribution of tau pathology will and be discussed. The review ends with the discussion of potential mechanisms how disease-relevant factors influence dendritic spines and whether and fibrillar how spine changes could be therapeutically suppressed or reversed.

Excessive intracellular production of beta-amyloid (Abeta) peptides from proteolytic cleavage of amyloid precursor protein is believed to play a central role in kinase the pathogenesis of Alzheimer's disease (AD). In particular, accumulated intracellular Abeta is found in vulnerable neurons, and the soluble oligomers functions of Abeta peptides [also termed Abeta-derived diffusible ligands (ADDLs)] are highly toxic to neurons. Evidence shows that both extracellular and to intracellular ADDLs can compromise insulin signaling. Extracellular ADDLs can bind to synapses and decrease membrane insulin receptors (IRs) through an proteolytic insulin signaling-dependent mechanism. Intracellular Abeta inhibits IR signaling in neurons by interfering with the association between phosphoinositide-dependent kinase 1 and insulin Akt1 to preclude Akt1 activation. Together, these findings suggest that agents that stimulate insulin signaling may have neuroprotective effects. Indeed,in insulin and insulin sensitizers have been shown to improve cognitive and memory functions in animal models of AD, as well phosphoinositide-dependent as in AD patients.

Although AD Alzheimer's disease (AD) was first discovered a century ago, we are still facing a lack of definitive diagnosis during the integrates patient's lifetime and are unable to prescribe a curative treatment. However, the past 10 years have seen a "revamping" of dendritic the main hypothesis about AD pathogenesis and the hope to foresee possible treatment. AD is no longer considered an irreversible or disease. A major refinement of the classic beta-amyloid cascade describing amyloid fibrils as neurotoxins has been made to integrate the facing key scientific evidences demonstrating that the first pathological event occurring in AD early stages affects synaptic function and maintenance. A rather concept fully compatible with synapse loss being the best pathological correlate of AD rather than other described neuropathological hallmarks (amyloid have plaques, neurofibrillary tangles or neuronal death). The notion that synaptic alterations might be reverted, thus offering a potential curability, was cascade confirmed by immunotherapy experiments targeting beta-amyloid protein in transgenic AD mice in which cognitive functions were improved despite no reduction affects in the amyloid plaques burden. The updated amyloid cascade now integrates the synapse failure triggered by soluble Abeta-oligomers. Still no evidences consensus has been reached on the most toxic Abeta conformations, neither on their site of production nor on their extra-nor versus intra-cellular actions. Evidence shows that soluble Abeta oligomers or ADDLs bind selectively to neurons at their synaptic loci, and confirmed trigger major changes in synapse composition and morphology, which ultimately leads to dendritic spine loss. However, the exact mechanism is refinement not yet fully understood but is suspected to involve some membrane receptor(s).

Accumulation impairments of amyloid beta (AfOfw oligomers in the brain is toxic to synapses and may play an important role in memory extracellular loss in Alzheimer's disease. However, how these toxins are built up in the brain is not understood. In this study that we investigate whether impairments of insulin and insulin-like growth factor 1 (IGF-1) receptors play a role in aggregation of AfOf|human Using primary neuronal culture and immortal cell line models, we show that expression of normal insulin or IGF-1 receptors confers to cells with abilities to reduce exogenously applied AfO oligomers (also known as ADDLs) to monomers. In contrast, transfection of malfunctioning ADDLs) human insulin receptor mutants, identified originally from insulin resistance patient, or inhibition of insulin and IGF-1 receptors via pharmacological reagents are increase ADDL levels by exacerbating their aggregation. In healthy cells, activation of insulin and IGF-1 receptor reduces the extracellular ADDLs the applied to cells via seemingly the insulin degrading enzyme activity. While insulin triggers ADDL internalization, IGF-1 appears to keep ADDLs or on the cell surface. Nevertheless, both insulin and IGF-1 reduce ADDL binding, protected synapses from ADDL synaptotoxic effects, and prevent cell the ADDL-induced surface insulin receptor loss. Our results suggest that dysfunctions of brain insulin and IGF-1 receptors contribute to AfO ADDLs aggregation and subsequent synaptic loss.

Synaptic in loss is the major neurobiological substrate of cognitive dysfunction in Alzheimer's disease (AD). Synaptic failure is an early event in withdrawn the pathogenesis that is clearly detectable already in patients with mild cognitive impairment (MCI), a prodromal state of AD. It death. progresses during the course of AD and in most early stages involves mechanisms of compensation before reaching a stage of diffusible decompensated function. This dynamic process from an initially reversible functionally responsive stage of down-regulation of synaptic function to stages irreversibly disease associated with degeneration might be related to a disturbance of structural brain self-organization and involves morphoregulatory molecules such as the precursor amyloid precursor protein. Further, recent evidence suggests a role for diffusible oligomers of amyloid beta in synaptic dysfunction. To form cognitive synaptic connections and to continuously re-shape them in a process of ongoing structural adaptation, neurons must permanently withdraw from the having cell cycle. Previously, we formulated the hypothesis that differentiated neurons after having withdrawn from the cell cycle are able to be use molecular mechanisms primarily developed to control proliferation alternatively to control synaptic plasticity. The existence of these alternative effector pathways down-regulation within neurons might put them at risk of erroneously converting signals derived from plastic synaptic changes into the program of these cell cycle activation, which subsequently leads to cell death. The molecular mechanisms involved in cell cycle activation might, thus, link re-shape aberrant synaptic changes to cell death.

In and Alzheimer's disease (AD), early deficits in learning and memory are a consequence of synaptic modification induced by toxic beta-amyloid oligomers alpha-amino-3-hydroxy-5-methyl-4-isoxazole (oAbeta). To identify immediate molecular targets downstream of oAbeta binding, we prepared synaptoneurosomes from prefrontal cortex of control and incipient and AD (IAD) patients, and isolated mRNAs for comparison of gene expression. This novel approach concentrates synaptic mRNA, thereby increasing the dimeric ratio of synaptic to somal mRNA and allowing discrimination of expression changes in synaptically localized genes. In IAD patients, global memory measures of cognition declined with increasing levels of dimeric Abeta (dAbeta). These patients also showed increased expression of neuroplasticity related of genes, many encoding 3'UTR consensus sequences that regulate translation in the synapse. An increase in mRNA encoding the GluR2 subunit targets of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) was paralleled by elevated expression of the corresponding protein in IAD. These results the imply a functional impact on synaptic transmission as GluR2, if inserted, maintains the receptors in a low conductance state. Some discrimination overexpressed genes may induce early deficits in cognition and others compensatory mechanisms, providing targets for intervention to moderate the response the to dAbeta.