Background: Acute kidney injury (AKI) has a complex pathophysiology and imposes serious health concerns worldwide. Extracellular vesicles (EVs) derived from induced mesenchymal stem cells (iMSCs) have been recognized as novel cell-free therapeutics for various inflammatory and degenerative disorders. In this study, we investigated whether iMSCs stimulated with a pan-peroxisome proliferator-activated receptor (PPAR) agonist could enhance the therapeutic efficacy of EVs against AKI.
Methods: Human iMSCs were primed with or without lanifibranor, a PPAR agonist for 24 h, and EVs were collected after an additional 24 h. The basic characteristics of EVs were evaluated using cryo-transmission electron microscopy imaging, immunoblot detection of EV markers, nanoparticle tracking analysis, and localization in AKI kidneys. In vitro, the potential of the EVs to promote the growth and survival of HK-2 cells undergoing cisplatin-induced apoptosis and anti-inflammatory effects in M1-polarized THP-1 was compared. Subsequently, AKI was induced in BALB/c mice using cisplatin. After 8 and 24 h of cisplatin treatment, iMSC-EVs or pan-PPAR-iMSC-EVs were injected intravascularly. At 96 h after cisplatin administration, the renoprotective effects of iMSC-EVs or pan-PPAR-iMSC-EVs in inhibiting inflammation and apoptosis were compared using serum biochemistry, histology, immunohistochemistry, and gene expression analysis by qPCR.
Results: Both EV types expressed EV markers and had typical EV morphology, and their localization in the renal tissue was confirmed. The proliferation and survival of HK-2 cells were higher in pan-PPAR-iMSC-EVs than those in iMSC-EVs. In M1-polarized THP-1 cells, the reduction in the mRNA expression of inflammatory cytokines was more significant in pan-PPAR-iMSC-EVs than that in iMSC-EVs. In the mouse model of cisplatin-induced AKI, pan-PPAR-iMSC-EVs markedly enhanced renoprotective effects compared to iMSC-EVs. Specifically, pan-PPAR-iMSC-EVs reduced tissue inflammation, immune cell infiltration, and apoptosis. Pan-PPAR-iMSC-EVs also increased renal capillary density.
Conclusion: Priming iMSCs with a PPAR agonist significantly improved the therapeutic potential of EVs by reducing inflammation and apoptosis. The reported strategy may contribute to the development of a novel cell-free option for AKI treatment.
Trial registration: Not applicable.
Keywords: Acute kidney injury; Extracellular vesicle; Induced mesenchymal stem cells; Priming.
© 2023. The Author(s).