| Protein misfolding and aggregation are characteristics of many neurodegenerative diseases including Alzheimer's disease (AD) and Parkinson's disease (PD). The common neuropathological hallmark linking these diseases is the accumulation of protein aggregates known as amyloid, consisting of highly insoluble amyloid fibrils. Although sequences of the proteins responsible in each disease differ from one to another, they all adopt the same 'cross-beta' secondary structure. In AD, the extracellular deposits are comprised of beta-amyloid while alpha-synuclein is found in the cytoplasmic inclusions in PD. The mechanism of amyloid formation is still unknown and increasing evidence suggests that the small soluble oligomeric intermediate protein is the relevant toxic species that cause neuronal dysfunction in AD and PD. The presence of oligomeric beta-amyloid and alpha-synuclein species precedes clinical symptoms and may serve as key therapeutic and diagnostic targets.;Single chain antibody fragments (scFvs) have been isolated against different forms of amyloid proteins. Here, a novel method to characterize scFv binding specificity using atomic force microscopy (AFM) was developed. The AFM method enables a fast, direct detection, visualization and quantification of specific antigen-antibody binding events with minimal protein handling. Finally, curcumin, a natural food pigment found in turmeric spice, has known anti-oxidant properties can inhibit toxic aggregation of alpha-synuclein and reduce toxicity of either intra- or extracellular alpha-synuclein.;Toxic oligomeric aggregates either inside or outside of the cells can induce apoptosis by various mechanisms including formation of pores in cell membrane, increased calcium influx across the membrane and increased oxidative stress ultimately leading to programmed cell death. The work presented here further investigates beta-amyloid aggregation and toxicity by studying the effects of simple carbohydrates on beta-amyloid aggregation kinetics and cytotoxicity toward SH-SY5Y human neuroblastoma cells. Cyclic carbohydrates such as cyclodextrins have been utilized as vehicles to transport therapeutics across the blood-brain barrier and to sequester cholesterol from cell bodies. The work here showed that cyclodextrins dramatically alter beta-amyloid aggregation, often increasing the accumulation of toxic beta-amyloid species, suggesting that additional studies are needed before using cyclodextrins to treat brain disorders. Antibodies and antibody fragments have also been studied as anti-aggregation agents for treating AD and PD. |
