Abstract
Purpose :
αB-crystallin super chaperone (αBΔ54-61) can be prepared by deleting 54-61 amino acid residues in αB-crystallin. The objective of this study was to evaluate the therapeutic potentials of αBΔ54-61 super chaperone using cell culture systems and C. elegans model system. Additionally, whether heat- or urea-induced unfolding and refolding of αBΔ54-61 and WT protein increases the proteins ability to protect cells from oxidative stress and apoptosis was also evaluated.
Methods :
The therapeutic efficacy of the WT- and Δ54-61-αB-crystallins was investigated a C. elegans model (CL4176) for Alzheimer's disease (AD). The αB-crystallin response to counter thermal and chemical-induced stress was studied using wild type (N2 strain) C. elegans. The chaperone-like activity of heat-/urea-activated wild-type and αBΔ54-61 were measured using luciferase and lysozyme as client proteins. The structural and molecular changes in Δ54-61-αB-crystallin after urea/heat activation were investigated using multi-angle light scattering analysis method. The cytoprotective effects of the native and heat/urea-activated αB-crystallins were evaluated in ARPE-19 cells using cell integrity assay and 2,7-dichlorofluorescin diacetate staining.
Results :
The super chaperone protected C. elegans (N2 strain) from paraquat and juglone-induced oxidative stress to a greater extent than did by wild-type αB-crystallin. The mutant super chaperone also prevented Aβ-induced toxicity on ARPE-19 cells in a more effective manner when compared to the wild-type protein. The mutant αB-crystallin also delayed Aβ-induced paralysis in a C. elegans model for AD and showed 10% increase in lifespan of the worm. C. elegans pre-treated with mutant αB-crystallin and exposed to thermal stress (35°C) showed a 11% increase in survival. In contrast, the wild-type protein treated worms showed no significant increase in survival when compared to placebo. Heat- and urea-induced unfolding/refolding events showed two-fold increase in the chaperone-like function with a concomitant increase in surface hydrophobicity of the mutant protein, even though increased hydrophobicity didn’t result in enhanced cytoprotective effects.
Conclusions :
Our findings suggest that αB-crystallin super chaperone (αBΔ54-61) has improved therapeutic potential in cell culture and C. elegans model system.
This is a 2021 ARVO Annual Meeting abstract.