The production of recombinant amyloid beta (rAβ) and the effect of exosome from stem cell human exfoliated deciduous teeth (SHED) on anti Aβ aggregation activity

Abstract

 Background: Soluble amyloid beta (Aβ) oligomers have been implicated in synaptotoxicity. These oligomers aggregate into large, insoluble fibrillar plaques, which contribute directly to neuronal cell death. The production of recombinant Aβ (rAβ) is essential for advancing research on its aggregation properties. By generating rAβ, researchers can explore novel therapeutic strategies aimed at modulating Aβ aggregation especially exosomes, it is well-known for their therapeutic potential in various diseases, for example Alzheimer’s disease (AD). Therefore, preventing Aβ aggregation represents a promising therapeutic strategy for AD, focusing on eliminating different forms of Aβ and mitigating their toxic effects.

Objective: This study aimed to produce and purify rAβ and investigate the anti-amyloid beta aggregation effects of exosomes derived from stem cells of human exfoliated deciduous teeth (SHED).

Methods: rAβ was expressed in E. coli Top10 transformed with the pBAD directional TOPO expression-Aβ1-42 vector (pBAD Aβ1-42). rAβ protein was then purified using Ni²z -NTA affinity chromatography. Finally, the Thioflavin T (Th-T) fluorescence assay was performed to evaluate the anti-Aβ aggregation properties of the exosomes.

Results: The E. coli pBAD Aβ1-42 produced rAβ protein (~25 kDa) which contained thioredoxin and a histidine tag following induction with 0.002% arabinose. Subsequent purification confirmed the successful isolation of rAβ, as verified by western blot analysis. Furthermore, exosomes demonstrated the ability to reduce Aβ aggregation ~1-fold change, as indicated by the Th-T fluorescence assay.

Conclusion: We successfully expressed and purified functional rAβ proteins, which can serve as valuable tools for assessing the potential of exosomes in preventing Aβ aggregation