Extracellular vesicles from hypoxia-preconditioned mesenchymal stem cells alleviates myocardial injury by targeting thioredoxin-interacting protein-mediated hypoxia-inducible factor-1α pathway

Figure 8 Thioredoxin-interacting protein promotes the ubiquitination of hypoxia-inducible factor-1 alpha through the chromosomal region maintenance-1 nuclear export pathway. A: H₉C₂ cardiomyocytes (CMs) overexpressing thioredoxin-interacting protein (TXNIP) or TXNIP-L294A mutant as indicated and leptomycin B were used to inhibit the chromosomal region maintenance 1 nuclear export pathway. The expression and cellular localization of hypoxia-inducible factor-1 alpha (HIF-1α) was analyzed by immunofluorescence staining; B: H₉C₂CMs were treated with hypoxia or normoxia and TXNIP was overexpressed as indicated. The expression of HIF-1α was analyzed by western blotting; C: H₉C₂ CMs were pretreated with MG132 for 2 h and TXNIP or TXNIP-L294A-mutant were overexpressed as indicated. The interaction of TXNIP and HIF-1α, and HIF-1α ubiquitination were assessed by immunoprecipitation with an anti-HIF-1α antibody; D: H₉C₂ CMs were pretreated with MG132 for 2 h. TXNIP was overexpressed and hypoxia treatment was applied as indicated. The interaction of TXNIP and HIF-1α, and HIF-1α ubiquitination were assessed by immunoprecipitation with an anti-HIF-1α antibody.