Trehalose Inhibits the Heat-Induced Formation of the Amyloid-Like Structure of Soluble Proteins Isolated from Human Cataract Lens.

The age-dependent loss of solubility and aggregation of crystallins constitute the pathological hallmarks of cataract. Several biochemical and biophysical factors are responsible for the reduction of crystallins' solubility and formation of irreversible protein aggregates, which display amyloid-like characteristics. The present study reports the heat-induced aggregation of soluble proteins isolated from human cataract lenses and the formation of amyloid-like structures. Exposure of protein at 55 °C for 4 h resulted in extensive (≈ 60%) protein aggregation. The heat-induced protein aggregates displayed substantial (≈ 20 nm) redshift in the wavelength of maximum absorption (λ) of Congo red (CR) and increase in Thioflavin T (ThT) fluorescence emission intensity, indicating the presence of amyloid-like structures in the heat-induced protein aggregates. Subsequently, the addition of trehalose resulted in substantial inhibition of heat-induced aggregation and the formation of amyloid-like structure. The ability of trehalose to inhibit the heat-induced aggregation was found to be linearly dependent upon its concentration used. The optimum effect was observed in the presence of 30-40% (w/v) trehalose where the aggregated was found to be reduced from 60 to 30%. The present study demonstrated the ability to trehalose to inhibit the protein aggregation and interfere with the formation of amyloid-like structures.