Key Points

Thrombomodulin on the cell surface acts as an anticoagulant and antifibrinolytic factor by binding to thrombin.Enhancement of thrombomodulin expression reduced renal infarction and pulmonary embolism induced by adipose-derived mesenchymal stem cells.Adipose-derived mesenchymal stem cells with enhanced thrombomodulin potentiated anti-inflammation and antifibrotic effects.

Background

Adipose-derived mesenchymal stem cells (ASCs) are expected to be a new therapy for organ injury; however, they were reported to have procoagulant activity, raising concerns about thrombogenic risk. Thrombomodulin acts as an anticoagulant factor by binding to thrombin, leading to the hypothesis that ASCs overexpressing thrombomodulin (TM-ASCs) could be safely used for cell therapy by reducing the risk of thromboembolism.

Methods

TM-ASCs were generated using adeno-associated virus carrying thrombomodulin cDNA. To examine the risk of ASC-induced renal infarction, ASCs were administered through renal artery into rats with unilateral ischemia-reperfusion injury (IRI) and contralateral nephrectomy. To assess the risk of ASC-induced pulmonary embolism, ASCs were injected into rats through tail vein. In addition, we examined whether TM-ASCs potently inhibited inflammatory cell infiltration and kidney fibrosis in IRI rats. Furthermore, we explored synthetic compounds that enhanced thrombomodulin expression in ASCs.

Results

Overexpression of thrombomodulin using adeno-associated virus reduced rat deaths related to renal infarction and pulmonary embolism induced by ASCs. TM-ASCs alleviated renal inflammation and fibrosis potently in IRI rats. The therapeutic mechanism of TM-ASCs involved increased prostaglandin E2 secretion, a shift in the macrophage phenotype to immunosuppressive M2 in vitro, and potent M2 macrophage polarization in the damaged areas in vivo. We produced ASCs with enhanced thrombomodulin expression by pretreatment with a selective inhibitory kappa-B kinase-β inhibitor. These ASCs also improved thrombotic mortality and markedly attenuated kidney fibrosis induced by IRI, similar to TM-ASCs generated by adeno-associated virus. ASCs with enhanced thrombomodulin expression by inhibitory kappa-B kinase-β inhibitor also increased prostaglandin E2 secretion, leading to a more pronounced polarization of M2 macrophages.

Conclusions

ASCs with enhanced thrombomodulin expression eliminated the risk of thrombosis and reinforced therapeutic efficacy.