Amyloid beta

beta amyloidbeta-amyloidβ-amyloidamyloid-betaamyloid-βamyloidamyloid-β peptideamyloid beta peptideamyloid β
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of people with Alzheimer's disease.wikipedia
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Amyloid precursor protein

APP(APPamyloid beta (A4) precursor protein
The peptides derive from the amyloid precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ.
APP is best known as the precursor molecule whose proteolysis generates beta amyloid (Aβ), a polypeptide containing 37 to 49 amino acid residues, whose amyloid fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease patients.

Peptide

polypeptidepeptidespolypeptides
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of people with Alzheimer's disease.
Finally, while aspects of the lab techniques applied to peptides versus polypeptides and proteins differ (e.g., the specifics of electrophoresis, chromatography, etc.), the size boundaries that distinguish peptides from polypeptides and proteins are not absolute: long peptides such as amyloid beta have been referred to as proteins, and smaller proteins like insulin have been considered peptides.

Alzheimer's disease

AlzheimerAlzheimer’s diseaseAlzheimer disease
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of people with Alzheimer's disease.
Most mutations in the APP and presenilin genes increase the production of a small protein called Aβ42, which is the main component of senile plaques.

Ion channel hypothesis of Alzheimer's disease

ion channel hypothesis
The ion channel hypothesis postulates that oligomers of soluble, non-fibrillar Aβ form membrane ion channels allowing the unregulated calcium influx into neurons that underlies disrupted calcium ion homeostasis and apoptosis seen in Alzheimer's disease.
The ion channel hypothesis of Alzheimer’s disease (AD), also known as the channel hypothesis or the amyloid beta ion channel hypothesis, is a more recent variant of the amyloid hypothesis of AD, which identifies amyloid beta (Aβ) as the underlying cause of neurotoxicity seen in AD.

Amyloid

amyloid plaquesamyloid plaqueamyloids
Amyloid beta (Aβ or Abeta) denotes peptides of 36–43 amino acids that are crucially involved in Alzheimer's disease as the main component of the amyloid plaques found in the brains of people with Alzheimer's disease.

Alpha-synuclein

α-synucleinSNCAalpha synuclein
Intra-cellular deposits of tau protein are also seen in the disease, and may also be implicated, as has aggregation of alpha synuclein.
An alpha-synuclein fragment, known as the non-Abeta component (NAC) of Alzheimer's disease amyloid, originally found in an amyloid-enriched fraction, was shown to be a fragment of its precursor protein, NACP.

PSEN1

presenilin 1presenilinpresenilin-1
Furthermore, mice that are in addition engineered to convert oligomers into plaques (APP E693Q X PS1ΔE9), are no more impaired than the oligomer only mice.
Presenilin-1 is one of the four core proteins in the gamma secretase complex, which is considered to play an important role in generation of amyloid beta (Aβ) from amyloid precursor protein (APP).

Glymphatic system

glymphatic
The glymphatic system clears metabolic waste from the mammalian brain, and in particular beta amyloids.
According to the prevailing amyloid hypothesis of Alzheimer's disease, the aggregation of amyloid-beta (a peptide normally produced in and cleared from the healthy young brain) into extracellular plaques drives the neuronal loss and brain atrophy that is the hallmark of Alzheimer's dementia.

Neprilysin

CD10neutral endopeptidasemembrane metallo-endopeptidase
Aβ is also destroyed by several amyloid-degrading enzymes including neprilysin.
It also degrades the amyloid beta peptide whose abnormal folding and aggregation in neural tissue has been implicated as a cause of Alzheimer's disease.

Alpha secretase

α-α-secretaseα-secretases
APP can be cleaved by the proteolytic enzymes α-, β- and γ-secretase; Aβ protein is generated by successive action of the β and γ secretases.
Specifically, alpha secretases cleave within the fragment that gives rise to the Alzheimer's disease-associated peptide amyloid beta when APP is instead processed by beta secretase and gamma secretase.

Tau protein

tauMAPTtau proteins
Intra-cellular deposits of tau protein are also seen in the disease, and may also be implicated, as has aggregation of alpha synuclein. The other protein implicated in Alzheimer's disease, tau protein, also forms such prion-like misfolded oligomers, and there is some evidence that misfolded Aβ can induce tau to misfold.
The A68 protein is a hyperphosphorylated Tau protein differing in its sensitivity and its Kinase as well as Alkaline phosphatase and is along with beta-amyloid a component of pathologic lesions in Alzheimer disease, and is found in the brains of individuals with Alzheimer's disease.

Inclusion body myositis

myositis, inclusion bodyinclusion-body myositis
Similar plaques appear in some variants of Lewy body dementia and in inclusion body myositis (a muscle disease), while Aβ can also form the aggregates that coat cerebral blood vessels in cerebral amyloid angiopathy.

Beta-secretase 1

BACE1beta secretaseβ-secretase
The peptides derive from the amyloid precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ. APP can be cleaved by the proteolytic enzymes α-, β- and γ-secretase; Aβ protein is generated by successive action of the β and γ secretases.
BACE1 is the major beta secretes for the generation of amyloid-β peptides in the neurons.

Cerebral amyloid angiopathy

cerebral amyloid angiopathy, familialamyloid angiopathyCongophilic angiopathy
Similar plaques appear in some variants of Lewy body dementia and in inclusion body myositis (a muscle disease), while Aβ can also form the aggregates that coat cerebral blood vessels in cerebral amyloid angiopathy. Amyloid beta may be primarily vascular, as in cerebral amyloid angiopathy, or in senile plaques in white matter.
It is usually associated with amyloid beta.

Gamma secretase

γ-secretasegamma-secretaseγ-secretases
The peptides derive from the amyloid precursor protein (APP), which is cleaved by beta secretase and gamma secretase to yield Aβ. APP can be cleaved by the proteolytic enzymes α-, β- and γ-secretase; Aβ protein is generated by successive action of the β and γ secretases.
The most well-known substrate of gamma secretase is amyloid precursor protein, a large integral membrane protein that, when cleaved by both gamma and beta secretase, produces a short 37-43 amino acid peptide called amyloid beta whose abnormally folded fibrillar form is the primary component of amyloid plaques found in the brains of Alzheimer's disease patients.

Down syndrome

Down's syndrometrisomy 21Downs Syndrome
Adults with Down syndrome had accumulation of amyloid in association with evidence of Alzheimer’s disease, including declines in cognitive functioning, memory, fine motor movements, executive functioning, and visuospatial skills.
The dementia which occurs in Down syndrome is due to an excess of amyloid beta peptide produced in the brain and is similar to Alzheimer's disease.

Crenezumab

Crenezumab is a fully humanized monoclonal antibody against human 1-40 and 1-42 Beta amyloid, which is being investigated as a treatment of Alzheimer's disease.

Semagacestat

β-Amyloid is a peptide of 39 to 43 amino acids.

Bapineuzumab

Bapineuzumab is an antibody to the beta-amyloid (Aβ) plaques that are believed to underlie Alzheimer's disease neuropathology.

Senile plaques

plaquessenile plaqueplaque
Amyloid beta may be primarily vascular, as in cerebral amyloid angiopathy, or in senile plaques in white matter.
Senile plaques (also known as neuritic plaques) are extracellular deposits of amyloid beta in the grey matter of the brain.

Pittsburgh compound B

PiBPiB PET
Imaging compounds, notably Pittsburgh compound B, (6-OH-BTA-1, a thioflavin), can selectively bind to amyloid beta in vitro and in vivo.
Pittsburgh compound B (PiB) is a radioactive analog of thioflavin T, which can be used in positron emission tomography scans to image beta-amyloid plaques in neuronal tissue.

Positron emission tomography

PETPET scanPET scans
This technique, combined with PET imaging, is used to image areas of plaque deposits in Alzheimer's patients.

Solanezumab

Solanezumab binds the amyloid-β peptides that aggregate and form plaques in the brain that are an early pathological feature of Alzheimer's disease.

Tarenflurbil

FlurizanR-flurbiprofen
Although this compound lacks activity against COX, studies have shown that this drug is a potent reducer of levels of beta amyloid, the main constituent of amyloid plaques in Alzheimer's disease, and therefore there was interest in this drug as a therapeutic agent.

Aducanumab

The antibody targets aggregated forms of β-amyloid found in the brains of people with Alzheimer’s disease, in the hopes of reducing its buildup.