Nano-assemblies enhance chaperone activity, stability, and delivery of alpha B-crystallin-D3 (αB-D3)

Crystallins, small heat shock chaperone proteins that prevent protein aggregation, are of potential value in treating protein aggregation disorders. However, their therapeutic use is limited by their low potency and poor intracellular delivery. One approach to facilitate the development of crystallins is to improve their activity, stability, and delivery. In this study, zinc addition to αB-crystallin-D3 (αB-D3) formed supramolecular nano- and micro- assemblies, induced dose-dependent changes in structure (beta-sheet to alpha-helix) and increased surface hydrophobicity and chemical stability. Further, crystallin assemblies exhibited a size-dependent chaperone activity, with the nano-assemblies being superior to micro-assemblies and 4.3-fold more effective than the native protein in preventing β-mercaptoethanol induced aggregation of insulin. Insulin rescued by crystallin assemblies retained the activity as evidenced by glucose uptake in 3T3-L1 cells. The most active nano-assemblies enhanced protein stability, in the presence of urea, by 1.6-fold, whereas intracellular delivery was enhanced by 3.0-fold. The αB-D3 crystallin nano-assemblies exhibit uniquely enhanced stability, activity, and delivery compared to the native protein. [Display omitted] •Nano- and micro- assemblies of αB-D3 crystallin with enhanced chemical stability, chaperone activity, and cell uptake were developed.•ZnCl2 promotes the formation of supramolecular assemblies of αB-D3 crystallin.•More ordered α-helix conformation was observed in αB-D3 crystallin with the addition of ZnCl2.•Addition of zinc ions allows the formation of chemically stable supramolecular assemblies of αB-D3 crystallin.