A plant cell-based system that predicts alpha beta 42 misfolding: Potential as a drug discovery tool for Alzheimer%26apos;s disease

作者：Zhao Tiehan; Zeng Ying; Kermode Allison R^*

来源：Molecular Genetics and Metabolism, 2012, 107(3): 571-579.

DOI：10.1016/j.ymgme.2012.08.010

• Alzheimer%26apos
• s disease
• Amyloid beta (A beta)
• Protein misfolding/aggregation
• GFP
• Hptll
• Plant cell

Alzheimer%26apos;s disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid beta (A beta) peptides and the failure of mechanisms to clear toxic aggregates. The A beta 42 peptide is considered to be a causative factor that underlies the pathophysiology of AD, in part due to its propensity for misfolding and aggregation; the small oligomers that result represent toxic species. Thus agents that prevent A beta 42 misfolding/ aggregation or, alternatively improve A beta 42 oligomer clearance, may have significant therapeutic value. We have developed the basis for a drug screening system based on transgenic plant cells that express A beta 42 fusion proteins to serve as the reliable indicators of the general conformational status of A beta 42. Within cells of transgenic tobacco and Nicotiana benthamiana, misfolding of A beta 42 causes the misfolding of a GFP fusion partner, and consequently there is a loss of fluorescence associated with the native GFP protein. In a similar fusion consisting of A beta 42 linked to hygromycin phosphotransferase II (Hpt II), a hygromycin-resistance marker, misfolding of A beta 42 leads to a misfolded Hpt II, and consequently the transgenic cells are unable to grow on media containing hygromycin. Importantly, substitution of the %26apos;aggregation-prone%26apos; A beta 42 with a missense mutant of A beta 42 (F19S/L34F) that is not prone to misfolding/aggregation, %26apos;rescues%26apos; both fusion partners. Several %26apos;positive control%26apos; chemicals that represent inhibitors of A beta 42 aggregation, including curcumin, epigallocatechin-3-gallate (EGCG), and resveratrol show efficacy in preventing the A beta 42-fusion proteins from misfolding/aggregating in the transgenic plant cells. We discuss the potential of the two fusion protein systems to serve as the basis for an inexpensive, selective, and efficient screening system in which a plant cell can fluoresce or survive only in the presence of drug candidates that are able to prevent A beta 42 misfolding/aggregation.

• 出版日期2012-11