Functional amyloids: interrelationship with other amyloids and therapeutic assessment to treat neurodegenerative diseases.

Misfolded β-sheet structures of proteins leading to neurodegenerative diseases like Alzheimer's disease (AD) and Parkinson's disease (PD) are in the spotlight since long. However, not much was known about the functional amyloids till the last decade. Researchers have become increasingly more concerned with the degree of involvement of these functional amyloids in human physiology. Interestingly, it has been found that the human body is exposed to a tremendous systemic amyloid burden, especially, during aging. Although many findings regarding these functional amyloids come up every day, some questions still remain unanswered like do these functional amyloids directly involve in the fibrillization of amyloid beta (Aβ) 42 peptide or enhance the Aβ42 aggregation rate; whether functional bacterial amyloids (FuBA) co-localize with the senile plaques of AD or not. A detailed review of the latest status regarding the interrelationship between functional amyloids, pathogenic amyloids and misfolded prions and therapeutic assessment of functional amyloids for the treatment of neurodegenerative diseases can help identify an alternative medication for neurodegeneration. A unique mathematical model is proposed here for alteration of Aβ42 aggregation kinetics in AD to carve out the future direction of therapeutic consideration.