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

Background: Soluble amyloid beta (A) 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 A (rA) is essential for advancing research on its aggregation properties.By generating rA, researchers can explore novel therapeutic strategies aimed at modulating A aggregation especially exosomes, it is well-known for their therapeutic potential in various diseases, for example Alzheimer's disease (AD).Therefore, preventing A aggregation represents a promising therapeutic strategy for AD, focusing on eliminating different forms of A and mitigating their toxic effects.Objective: This study aimed to produce and purify rA and investigate the anti-amyloid beta aggregation effects of exosomes derived from stem cells of human exfoliated deciduous teeth (SHED).Methods: rA was expressed in E. coli Top10 transformed with the pBAD directional TOPO expression-A1-42 vector (pBAD A1-42).rA protein was then purified using Niz -NTA affinity chromatography.Finally, the Thioflavin T (Th-T) fluorescence assay was performed to evaluate the anti-A aggregation properties of the exosomes.Results: The E. coli pBAD A1-42 produced rA protein (~25 kDa) which contained thioredoxin and a histidine tag following induction with 0.002% arabinose.Subsequent purification confirmed the successful isolation of rA, as verified by western blot analysis.Furthermore, exosomes demonstrated the ability to reduce A aggregation ~1-fold change, as indicated by the Th-T fluorescence assay. Conclusion:We successfully expressed and purified functional rA proteins, which can serve as valuable tools for assessing the potential of exosomes in preventing A aggregation.