Published online Feb 26, 2022. doi: 10.4252/wjsc.v14.i2.183
Peer-review started: October 13, 2021
First decision: November 8, 2021
Revised: November 29, 2021
Accepted: January 25, 2022
Article in press: January 25, 2022
Published online: February 26, 2022
Processing time: 134 Days and 20.8 Hours
Extracellular vesicles (EVs) derived from hypoxia-preconditioned (HP) mesenchymal stem cells (MSCs) have better cardioprotective effects against myocardial infarction (MI) in the early stage than EVs isolated from normoxic (NC)-MSCs. However, the cardioprotective mechanisms of HP-EVs are not fully understood.
To explore the cardioprotective mechanism of EVs derived from HP MSCs.
We evaluated the cardioprotective effects of HP-EVs or NC-EVs from mouse adipose-derived MSCs (ADSCs) following hypoxia in vitro or MI in vivo, in order to improve the survival of cardiomyocytes (CMs) and restore cardiac function. The degree of CM apoptosis in each group was assessed by the terminal deoxynucleotidyl transferase dUTP nick end-labeling and Annexin V/PI assays. MicroRNA (miRNA) sequencing was used to investigate the functional RNA diversity between HP-EVs and NC-EVs from mouse ADSCs. The molecular mechanism of EVs in mediating thioredoxin-interacting protein (TXNIP) was verified by the dual-luciferase reporter assay. Co-immunoprecipitation, western blotting, and immunofluorescence were performed to determine if TXNIP is involved in hypoxia-inducible factor-1 alpha (HIF-1α) ubiquitination and degradation via the chromosomal region maintenance-1 (CRM-1)-dependent nuclear transport pathway.
HP-EVs derived from MSCs reduced both infarct size (necrosis area) and apoptotic degree to a greater extent than NC-EVs from CMs subjected to hypoxia in vitro and mice with MI in vivo. Sequencing of EV-associated miRNAs showed the upregulation of 10 miRNAs predicted to bind TXNIP, an oxidative stress-associated protein. We showed miRNA224-5p, the most upregulated miRNA in HP-EVs, directly combined the 3’ untranslated region of TXNIP and demonstrated its critical protective role against hypoxia-mediated CM injury. Our results demonstrated that MI triggered TXNIP-mediated HIF-1α ubiquitination and degradation in the CRM-1-mediated nuclear transport pathway in CMs, which led to aggravated injury and hypoxia tolerance in CMs in the early stage of MI.
The anti-apoptotic effects of HP-EVs in alleviating MI and the hypoxic conditions of CMs until reperfusion therapy may partly result from EV miR-224-5p targeting TXNIP.
Core Tip: Extracellular vesicles (EVs) from adipose-derived mesenchymal stem cells treated with hypoxia preconditioning improve tolerance toward myocardial infarction or hypoxic conditions and alleviate the degree of cardiomyocyte apoptosis until reperfusion therapy. The anti-apoptotic effects may result from EV miR-224-5p targeting thioredoxin-interacting protein (TXNIP) and subsequent TXNIP-mediated hypoxia-inducible factor-1 alpha ubiquitination and degradation via the chromosomal region maintenance-1-mediated nuclear transport pathway.