Introduction: Metallothioneins (MTs) are a class of ubiquitously occurring low-molecular-weight cysteine- and metal-rich proteins containing sulfur-based metal clusters. MT-3 exhibits neuro-inhibitory activity. The possibility to enhance the expression of MT-3 or protect it from degradation is an attractive therapeutic target, because low levels of MT-3 were found in brains of Alzheimer's disease (AD) patients.
Objectives: The primary objective of this study was to test an enhancement of MT-3 cellular concentration after MT-3 binding treatment, which could prevent MT-3 degradation.
Methods: MTT assay, flow-cytometry, fluorescence microscopy, quantitative real-time polymerase chain reaction, and immunodetection of MT3 were used for analysis of effect of STOCK1N-26544, STOCK1N-26929, and STOCK1N-72593 on immortalized human microglia-SV40 cell line.
Results: All three tested compounds enhanced concentration of MT-3 protein in cells and surprisingly also mRNA concentration. IC50 values of tested molecules exceeded about ten times the concentration that was needed for induction of MT-3 expression. The tested compound Benzothiazolone-2 enhanced apoptosis and necrosis, but it was not of severe effect. About 80% of cells were still viable. There was no serious ROS-generation and no severe decrease in mitochondria numbers or stress induced endoplasmic reticulum changes after test treatments. The selected compound showed stable hydrophobic and electrostatic interaction during MT-3 ligand interaction.
Conclusion: Benzothiazolone-2 compounds significantly enhanced MT-3 protein and mRNA levels. The compounds can be looked upon as one of the probable lead compounds for future drug designing experiments in the treatment of Alzheimer's disease.
Keywords: Alzheimer's disease; flow cytometry; immunodetection; metallothionein‐3; molecular dynamics; qRT‐PCR.