摘要
Background and Aims:Transplantation of mesenchymal stem cells(MSCs)derived from bone marrow(BM)is an alternative treatment of acute liver failure(ALF)mainly be-cause of the resulting anti-inflammatory activity.It is not known how MSCs regulate local immune responses and liver regeneration.This study explored the effects of MSCs on hepatic macrophages and the Wnt signaling pathway in ALF.Methods:MSCs were isolated from BM aspirates of C57BL/6J mice,and transplanted in mice with ALF induced by D-galactosamine(D-Gal).The proliferation of hepato-cytes was assayed by immunohistochemical(IHC)staining of Ki-67 and proliferating cell nuclear antigen(PCNA).The levels of key proteins in the Wnt signaling pathway were assayed by western blotting and cytokines were determined enzyme-linked immunosorbent assays(ELISAs).A mac-rophage polarization assay characterized the M1/M2 ratio.The potential role of interleukin-4(IL-4)in the biological ac-tivity of MSCs was determined by silencing of IL-4.Results:Transplantation of allogeneic MSCs significantly attenuated D-Gal-induced hepatic inflammation and promoted liver re-generation.MSC transplantation significantly promoted a phenotypic switch from proinflamatory M1 macrophages to anti-inflammatory M2 macrophages,leading to significant Wnt-3a induction and activation of the Wnt signaling path-way in mice with D-Gal-induced ALF.Of the paracrine fac-tors secreted by MSCs(G-CSF,IL-6,IL-1 beta,IL-4,and IL-17A),IL-4 was specifically induced following transplantation in the ALF model mice.The silencing of IL-4 significantly ab-rogated the phenotypic switch to M2 macrophages and the protective effects of MSCs in both the ALF model mice and a co-culture model in an IL-4 dependent manner.Conclu-sions:In vivo and in vitro studies showed that MSCs ame-liorated ALF through an IL-4-dependent macrophage switch toward the M2 anti-inflammatory phenotype.The findings may have clinical implications in that overexpression of IL-4 may enhance the therapeutic effects of allogeneic MSC transplantation in the treatment of ALF.
基金
This work was funded by the National Natural Science Foundation of China(81872359)
Jiangsu Provincial key research and development(BE2020752)
the Natural Science Foundation of Jiangsu Province(BK20190114)
the Nanjing Medical Science and Technique Development Foundation(QRX17129)
Key Project supported by Medical Science and technology development Foundation,Nanjing Department of Health(JQX19002,YKK19070)
the Nanjing Science and technology project(201911039)
the Fundamental Research Funds for the Central Universities(0214-YG1312037)
Project of Modern Hospital Management and Development Institute,Nanjing University and Aid project of Nanjing Drum Tower Hospital Health,Education&Research Foundation(NDYG2020047).