The amyloid β-peptide (Aβ) has a central role in initiating neurodegeneration in Alzheimer disease (AD) ¹. It is widely believed to be an incidental catabolic byproduct of the amyloid β protein precursor (APP) with no normal physiological function.²

Aβ has been shown to be a ligand for a number of different receptors and other molecules^3-5.  It is transported between tissues and across the blood brain barrierby complex trafficking pathways⁶.  Aβ is modulated in response to a variety of environmental stressors and is able to induce pro-inflammatory activities⁷.

Soluble amyloid β-peptide fragment that is a substrate for gelatinase A/type IV collagenase/MMP-2 and APP secretase; cleaved between Lys16 and Leu17.

Figure1. Structure of Amyloid β-Peptide

Ref:

1. Small, D.H., Mok, S.S. & Bornstein, J.C. Alzheimer’s disease and Aβ-toxicity: From top to bottom. Nature Rev. Neurosci. 2, 595–598 (2001)

2. Soscia SJ, Kirby JE, Washicosky KJ, Tucker SM, Ingelsson M, Hyman B, Burton MA, Goldstein LE, Duong S, Tanzi RE, Moir RD (2010). Bush, Ashley I.. ed. The Alzheimer's Disease-Associated Amyloid β-Protein Is an Antimicrobial Peptide. PLoS ONE 5 (3)

3. Le Y, Gong W, Tiffany HL, Tumanov A, Nedospasov S, et al. (2001) Amyloid (b)42 activates a G-protein-coupled chemoattractant receptor, FPR-like-1.J Neurosci 21: RC123.

4. Koldamova RP, Lefterov IM, Lefterova MI, Lazo JS (2001) Apolipoprotein A-I directly interacts with amyloid precursor protein and inhibits Ab aggregation and toxicity. Biochemistry 40: 3553–3560.

5. Maezawa I, Jin LW, Woltjer RL, Maeda N, Martin GM, et al. (2004) Apolipoprotein E isoforms and apolipoprotein AI protect from amyloid precursor protein carboxy terminal fragment-associated cytotoxicity. J Neurochem 91: 1312–1321.

6. Tanzi RE, Moir RD, Wagner SL (2004) Clearance of Alzheimer’s Ab peptide: the many roads to perdition. Neuron 43: 605–608.

7. Paris D, Town T, Parker TA, Tan J, Humphrey J, et al. (1999) Inhibition of Alzheimer’s b-amyloid induced vasoactivity and proinflammatory response in microglia by a cGMP-dependent mechanism. Exp Neurol 157: 211–221.