Transplantation of Mesenchymal Stem Cells Attenuates Acute Liver Failure in Mice via an Interleukin-4-dependent Switch to the M2 Macrophage Anti-inflammatory Phenotype

Abstract

Background and Aims: Transplantation of mesenchymal stem cells (MSCs) derived from bone marrow (BM) is an alternative treatment of acute liver failure (ALF) mainly because 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 hepatocytes 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 macrophage polarization assay characterized the M1/M2 ratio. The potential role of interleukin-4 (IL-4) in the biological activity of MSCs was determined by silencing of IL-4. Results: Transplantation of allogeneic MSCs significantly attenuated D-Gal-induced hepatic inflammation and promoted liver regeneration. 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 pathway in mice with D-Gal-induced ALF. Of the paracrine factors 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 abrogated 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. Conclusions: In vivo and in vitro studies showed that MSCs ameliorated 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.

Comparison of the Efficacy of Two Routes of Administration of Human Amniotic Epithelial Cells in Cell Therapy of Acute Hepatic Insufficiency

“…The activated Kupffer cells produce substances such as TNF-α and IL-1β, which induce increased expression of E- and P-selectins on vascular endothelial cells, enabling the inflow of not only neutrophils and monocytes but also hAECs [ 50 , 58 ]. A paracrine therapeutic effect was also obtained in the ALF mouse model after administration of MSCs derived both from bone marrow and adipose tissue, which, despite not being engrafted in the liver, reduced the hepatotoxic effects [ 59 , 60 ]. Compared to intravenous administration, intraperitoneal administration of the cells should potentially favour their direct effect on the damaged liver due to their close proximity to this organ and the possibility of more intense attraction to the damage site by chemoattractants such as SDF-1.…”

The Role of Immune Cells in Liver Regeneration

“…Recently, the transplantation of mesenchymal stem cells (MSCs) has been established as a potential strategy to trigger restorative macrophages. MSC transplantation promotes IL-4-dependent M2 macrophage switching and hepatocyte proliferation, and improves outcomes in mice with acute liver injury induced by GaIN [42], as well as in mice with chronic liver injury induced by multiple doses of CCl 4 [43]. Another single-cell RNA sequencing (scRNAseq) study highlighted that MSC treatment promoted the transition of hepatic macrophages from an Ly6C high to an Ly6C low population in mice with acute liver injury [44].…”

Advances in Mesenchymal stem cells regulating macrophage polarization and treatment of sepsis-induced liver injury

“…Simultaneously, the upregulation of Wnt-3a expression is induced by MSCs. Facilitating the shift from the M1 pro-inflammatory phenotype to the M2 anti-inflammatory phenotype (38). Through the coencapsulation of hepatocytes and human umbilical cord MSCs (HNF4a-UMSCs), a series of beneficial effects have been observed.…”