IntroductionStudies have demonstrated that mesenchymal stromal cells (MSCs) could reverse acute and chronic kidney injury by a paracrine or endocrine mechanism, and microvesicles (MVs) have been regarded as a crucial means of intercellular communication. In the current study, we focused on the therapeutic effects of human Wharton-Jelly MSCs derived microvesicles (hWJMSC-MVs) in renal ischemia/reperfusion injury and its potential mechanisms.MethodsMVs isolated from conditioned medium were injected intravenously in rats immediately after ischemia of the left kidney for 60 minutes. The animals were sacrificed at 24 hours, 48 hours and 2 weeks after reperfusion. The infiltration of inflammatory cells was identified by the immunostaining of CD68+ cells. ELISA was employed to determine the inflammatory factors in the kidney and serum von Willebrand Factor (VWF). Tubular cell proliferation and apoptosis were identified by immunostaining. Renal fibrosis was assessed by Masson’s tri-chrome straining and alpha-smooth muscle actin (α-SMA) staining. The CX3CL1 expression in the kidney was measured by immunostaining and Western blot, respectively. In vitro, human umbilical vein endothelial cells were treated with or without MVs for 24 or 48 hours under hypoxia injury to test the CX3CL1 by immunostaining and Western blot.ResultsAfter administration of hWJMSC-MVs in acute kidney injury (AKI) rats, renal cell apoptosis was mitigated and proliferation was enhanced, inflammation was also alleviated in the first 48 hours. MVs also could suppress the expression of CX3CL1 and decrease the number of CD68+ macrophages in the kidney. In the late period, improvement of renal function and abrogation of renal fibrosis were observed. In vitro, MVs could down-regulate the expression of CX3CL1 in human umbilical vein endothelial cells under hypoxia injury at 24 or 48 hours.ConclusionsA single administration of MVs immediately after ischemic AKI could ameliorate renal injury in both the acute and chronic stage, and the anti-inflammatory property of MVs through suppression of CX3CL1 may be a potential mechanism. This establishes a substantial foundation for future research and treatment.

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Several studies suggest that mesenchymal stem cells (MSCs) possess antitumor properties; however, the exact mechanisms remain unclear. Recently, microvesicles (MVs) are considered as a novel avenue intercellular communication, which may be a mediator in MSCs-related antitumor effect. In the present study, we evaluated whether MVs derived from human umbilical cord Wharton’s jelly mesenchymal stem cells (hWJMSCs) may inhibit bladder tumor T24 cells growth using cell culture and the BALB/c nu/nu mice xenograft model. CCK-8 assay and Ki-67 immunostaining were performed to estimate cell proliferation in vitro and in vivo. Flow cytometry and TUNEL assay were used to assess cell cycle and apoptosis. To study the conceivable mechanism by which hWJMSC-MVs attenuate bladder tumor T24 cells, we estimated the expression of Akt/p-Akt, p-p53, p21 and cleaved Caspase 3 by Western blot technique after exposing T24 cells to hWJMSC-MVs for 24, 48 and 72h. Our data indicated that hWJMSC-MVs can inhibit T24 cells proliferative viability via cell cycle arrest and induce apoptosis in T24 cells in vitro and in vivo. This study showed that hWJMSC-MVs down-regulated phosphorylation of Akt protein kinase and up-regulated cleaved Caspase 3 during the process of anti-proliferation and pro-apoptosis in T24 cells. These results demonstrate that hWJMSC-MVs play a vital role in hWJMSC-induced antitumor effect and may be a novel tool for cancer therapy as a new mechanism of cell-to-cell communication.