Search results for "Alzheimer's"

Imaging P-Glycoprotein Induction at the Blood–Brain Barrier of a β-Amyloidosis Mouse Model with 11C-Metoclopramide PET

2019

P-glycoprotein (ABC subfamily B member 1, ABCB1) plays an important role at the blood–brain barrier (BBB) in promoting clearance of neurotoxic β-amyloid (Aβ) peptides from the brain into the blood. ABCB1 expression and activity were found to be decreased in the brains of Alzheimer disease patients. Treatment with drugs that induce cerebral ABCB1 activity may be a promising approach to delay the build-up of Aβ deposits in the brain by enhancing clearance of Aβ peptides from the brain. The aim of this study was to investigate whether PET with the weak ABCB1 substrate radiotracer 11C-metoclopramide can measure ABCB1 induction at the BBB in a β-amyloidosis mouse model (APP/PS1-21 mice) and in w…

The unsolved relationship of brain aging and late-onset Alzheimer disease.

2009

Late-onset Alzheimer disease is the most common form of dementia and is strongly associated with age. Today, around 24 million people suffer from dementia and with aging of industrial populations this number will significantly increase throughout the next decades. An effective therapy that successfully decelerates or prevents the progressive neurodegeneration does not exist. Histopathologically Alzheimer disease is characterized by extensive extracellular amyloid beta (Abeta) plaques, intracellular neurofibrillary tangles (NFTs), synaptic loss and neuronal cell death in distinct brain regions. The molecular correlation of Abeta or NFTs and development of late-onset Alzheimer disease needs f…

Thioflavin T templates amyloid β(1–40) conformation and aggregation pathway

2015

Aβ(1-40) peptide supramolecular assembly and fibril formation processes are widely recognized to have direct implications in the progression of Alzheimer's disease. The molecular basis of this biological process is still unknown and there is a strong need of developing effective strategies to control the occurring events. To this purpose the exploitation of small molecules interacting with Aβ aggregation represents one of the possible routes. Moreover, the use specific labeling has represented so far one of the most common and effective methods to investigate such a process. This possibility in turn rests on the reliability of the probe/labels involved. Here we present evidences of the effe…

The Metalloprotease Meprin β Generates Amino Terminal-truncated Amyloid β Peptide Species

2012

The amyloid β (Aβ) peptide, which is abundantly found in the brains of patients suffering from Alzheimer disease, is central in the pathogenesis of this disease. Therefore, to understand the processing of the amyloid precursor protein (APP) is of critical importance. Recently, we demonstrated that the metalloprotease meprin β cleaves APP and liberates soluble N-terminal APP (N-APP) fragments. In this work, we present evidence that meprin β can also process APP in a manner reminiscent of β-secretase. We identified cleavage sites of meprin β in the amyloid β sequence of the wild type and Swedish mutant of APP at positions p1 and p2, thereby generating Aβ variants starting at the first or seco…

Alcadein cleavages by amyloid beta-precursor protein (APP) alpha- and gamma-secretases generate small peptides, p3-Alcs, indicating Alzheimer disease…

2009

Alcadeins (Alcs) constitute a family of neuronal type I membrane proteins, designated Alc(alpha), Alc(beta), and Alc(gamma). The Alcs express in neurons dominantly and largely colocalize with the Alzheimer amyloid precursor protein (APP) in the brain. Alcs and APP show an identical function as a cargo receptor of kinesin-1. Moreover, proteolytic processing of Alc proteins appears highly similar to that of APP. We found that APP alpha-secretases ADAM 10 and ADAM 17 primarily cleave Alc proteins and trigger the subsequent secondary intramembranous cleavage of Alc C-terminal fragments by a presenilin-dependent gamma-secretase complex, thereby generating "APP p3-like" and non-aggregative Alc pe…

Polymorphisms of pro-inflammatory genes and Alzheimer's disease risk: A pharmacogenomic approach.

2006

Clinically and pathologically Alzheimer's disease (AD) represents a sequential progressive neurodegenerative disorder. AD is etiologically heterogeneous and accounts for a majority of dementia in western societies. Inflammation clearly occurs in pathologically vulnerable regions of the AD brain and the search for genetic factors influencing the pathogenesis of AD has lead to the identification of numerous gene polymorphisms that might act as susceptibility modifiers. Accordingly, several reports have indicated that the risk of AD is substantially influenced by several genetic polymorphisms in the promoter region, or other untranslated regions, of genes encoding inflammatory mediators, altho…

Visual hallucinations and agitation in Alzheimer's Disease due to memantine: report of three cases

2007

Memantine, a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist, is currently the only drug proposed for the treatment of moderate to severe Alzheimer’s disease.1 It has been shown to have neuroprotective effects by inhibiting the excitotoxic effect of NMDA glutamate receptors.2 Memantine has a tolerability profile similar to placebo.1 However, the worsening of psychotic symptoms in patients with Lewy body dementia (LBD) treated with memantine has been recently reported.3 We describe three patients with probable Alzheimer’s disease who developed worsening or de novo visual hallucinations and agitation after memantine treatment. Patient 1 was a 65-year-old woman with a 2-year hi…

Curcumin-Like Compounds as Neuroprotective Agents: Interactions with HSP60 and Amyloid Beta Peptide

2014

Alzheimer’s Disease (AD) represents a fundamental challenge for public health in the 21st century. Current AD therapies largely focus on symptomatic aspects of the clinical pathology, but they have yet to demonstrate any major impact on the disease progression [1]. The most important role of the research aimed at fighting the AD is the development of neuro-protective agents, able to interfere with the protein aggregation process whose clinical signature is represented by the plaques deposition. An important role in AD’s framework could be played by Heat shock proteins (HSPs), highly regulated proteins that mediate the proteins proper folding and promote recovery of their native conformation…

NEUROINFLAMMATION AND SYNAPTIC IMBALANCE IN ALZHEIMER’S DISEASE

2020

THE ROLE OF HSP60 IN AMYLOID BETA PATHWAY: RELEVANCE TO ALZHEIMER’S DISEASE

Alzheimer’s disease (AD) is a devastating neurodegenerative disorder affecting more than 40 million individuals worldwide. The high number of factors triggering the onset of AD justifies the current absence of disease-modifying therapies. The involved pathological mechanisms are still elusive and, therefore, the finding of effective therapies requires further elucidation of biomolecular mechanisms controlling AD pathogenesis. Particularly, the aberrant amyloidogenic cleavage of amyloid precursor protein (APP), amyloid beta (Aβ) peptide misfolding and oligomerization, and the impairment of the protein quality control machinery are key hallmarks characterizing the onset of the disease. Furthe…