[Heat-shock protein HSP70 decreases activity of proteasomes in human neuroblastoma cells treated by amyloid-beta 1-42 with isomerized Asp7].

Experimental evidences indicate that heat-shock protein 70 (HSP70) can serve as a prospective therapeutic agent to treat Alzheimer's disease (AD). It has demonstrated a neuroprotective effect in vivo on mice models of AD. Moreover, HSP70 decreases oxidative stress in neurons induced by amyloid-β (Aβ42) and its more toxic form with isomerized Asp7 (isoAβ42). The dysfunction of Ubiquitin-proteasome system (UPS) is observed in AD. UPS is responsible for the degradation of the majority of cellular proteins and plays an important role in protecting cells from oxidative stress. Here, we have shown that the incubation of human neuroblastoma cells SK-N-SH with isoAβ42 increases the activity of intracellular proteasomes, which are the principal elements of the UPS. On the contrary, the proteasomal activity was decreased in isoAβ42-treated cells in the presence of exogenous HSP70. These results highlight the existence of an interplay between Aβ peptides, proteasomes, and HSP70.