Fig. 4: 26S proteasome activity and HSP90α levels were downregulated in hypoxic rat MSCs.
From: Hypoxia-induced 26S proteasome dysfunction increases immunogenicity of mesenchymal stem cells
a To measure 26S activity, the levels of both 19S (deubiquitinating activity) and 20S (proteolysing activity) were determined. The activities were measured by using flurogenic substrates:- U-555 for 19S and SUC-LLVY-AMC for 20S. Hypoxic MSCs were found to have a marked reduction in 26S activity (n = 3). b, c NOB1, BLM10, HSP90α, and HSP90β mRNA and protein levels were determined by RT-PCR and western blotting. NOB1, BLM10, and HSP90β levels did not change in MSCs after exposure to hypoxia for 24 h. However, HSP90α mRNA and protein levels decreased in hypoxia-exposed MSCs (n = 4); *p < 0.05 compared with normoxic MSC. Each experiment was repeated four to six times
