Bis(indolyl)phenylmethane derivatives are effective small molecules for inhibition of amyloid fibril formation by hen lysozyme.
Amyloid or similar protein aggregates are the hallmarks of many disorders, including Alzheimer's, Parkinson's, Huntington's diseases and amyloidoses. The inhibition of the formation of these aberrant species by small molecules is a promising strategy for disease treatment. However, at present, all such diseases lack an appropriate therapeutic approach based on small molecules. In this work we have evaluated five bis(indolyl)phenylmethane derivatives to reduce amyloid fibril formation by hen egg white lysozyme (HEWL) and its associated cytotoxicity. HEWL is a widely used model system to study the fundamentals of amyloid fibril formation and is heterologous to human lysozyme, which forms amyloid fibrils in a familial form of systemic amyloidosis. HEWL aggregation was tested in the presence and absence of the five compounds, under conditions in which the protein is partially unfolded. To this purpose, various techniques were used, including Congo red and Thioflavin T binding assays, atomic force microscopy, Fourier-Transform Infrared spectroscopy and cell-based cytotoxicity assays, such as the MTT reduction test and the trypan blue test. It was found that all compounds inhibited the formation of amyloid fibrils and their associated toxicity, diverging the aggregation process towards the formation of large, morphologically amorphous, unstructured, nontoxic aggregates, thus resembling class I molecules defined previously. In addition, the five compounds also appeared to disaggregate pre-formed fibrils of HEWL, which categorizes them into class IA. The half maximal inhibitory concentration (IC50) was found to be ca 12.3 ± 1.0 μM for the forefather compound.
Biology Department, Payam Noor University, 19395-4697 Tehran, Islamic Republic of Iran.
Hassan
H
Ramshini
Department of Chemistry, University of Cambridge, Cambridge, United Kingdom; Section of Biochemical Sciences, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy.
Benedetta
B
Mannini
Biology Department, Payam Noor University, 19395-4697 Tehran, Islamic Republic of Iran.
Kaveh
K
Khodayari
Endocrinology and Metabolism Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran; Modeling and Simulation Group, Endocrinology and Metabolism Molecular -Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran.
Azadeh
A
Ebrahim-Habibi
Biology Department, Payam Noor University, 19395-4697 Tehran, Islamic Republic of Iran.
Azam Sadat
AS
Moghaddasi
Department of Chemistry, School of Sciences, Hakim Sabzevari University, Iran.
Reza
R
Tayebee
Section of Biochemical Sciences, Department of Biomedical, Experimental and Clinical Sciences, University of Florence, Florence, Italy. Electronic address: fabrizio.chiti@unifi.it.
Fabrizio
F
Chiti
D000682:Amyloid / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007211:Indoles / Q000737:chemistry* / Q000494:pharmacology* / Q000633:toxicity; D007700:Kinetics; D061986:MCF-7 Cells; D009113:Muramidase / Q000737:chemistry*; D066329:Protein Aggregates / Q000187:drug effects*
D000682:Amyloid; D007211:Indoles; D066329:Protein Aggregates; C421864:hen egg lysozyme; D009113:Muramidase
Amyloid aggregation inhibitors; Aromatic compounds; Drug discovery; Indolyl methanes; Protein misfolding