Galectin-1 Restores Immune Tolerance to Liver Transplantation Through Activation of Hepatic Stellate Cells

Abstract

Background/Aims: Immune tolerance is considered the only way to manage liver transplantation (LT). The current study hypothesized that galectin-1 via the activation of hepatic stellate cells (HSCs) is capable of inducing immune tolerance in LT. Methods: Lentiviral-mediated gene knockdown and overexpression of galectin-1 were conducted in HSC-T6 cells. Reverse transcription quantitative polymerase chain reaction and western blot analysis were used to determine galectin-1 expression. LT was performed in 20 C57BL/J6 mice and 20 C3H mice. T-cells were assigned into control, Galectin-1 shRNA, Galectin-1 OE, Galectin-1 OE SB431542, Galectin-1 OE Sulforaphane, Galectin-1 OE Y27632, and Galectin-1 OE UO126 groups. CFSE, flow cytometry, and ELISA were respectively employed to detect T-cell proliferation, CD4⁺/ CD8⁺ ratio and IL-2, IL-10 and TGF-β levels. After establishing mouse models of immune tolerance and acute rejection, immunohistochemistry, TUNEL, and immunofluorescence assay were performed to determine CD3⁺ expression, apoptosis, α-SMA, and desmin. Mouse models of CCl4-induced liver fibrosis were established, followed by assigning the control₁ and CCl4 groups. ELISA was used to determine ALT, AST, TBIL and Hyp levels. A total of 3 C57BL/J6 mice (donor) and 6 C3H mice (recipient) were grouped into the control₂ and UO126 groups, followed by ELISA detection for IL-2, IL-10 and TGF-β. Results: In T-cells, galectin-1 shRNA increased cell proliferation and IL-2 levels with reduced IL-10 and TGF-β levels, while the Galectin-1 OE and Galectin-1 OE UO126 groups revealed the opposite results. Galectin-1 overexpression elevated the ratio of the CD4⁺ to CD8⁺ T-cells. The acute rejection group exhibited enhanced desmin expression and reduced α-SMA expression. Compared with the immune tolerance group, the acute rejection group displayed higher galectin-1 expression, a positive expression rate of CD3⁺ T-cells, and an increased apoptosis rate. Compared with the control₁ group, the CCl4 group exhibited higher galectin-1 expression, ALT, AST, TBIL, and Hyp levels, α-SMA expression and CD4⁺/CD8⁺ T-cell ratio, in addition to decreased expression of desmin. Compared with the control₂ group, UO126 increased galectin-1 expressions, IL-10 and TGF-β levels and reduced IL-2 levels with inactivated HSCs. Conclusions: The findings of the current study indicated that the overexpression of galectin-1 promoted the activation of HSCs, which reduced the inflammatory response by exerting immunosuppressive effects and accordingly contributed to immune tolerance in LT.

Transplant Tolerance Induction: Insights From the Liver

“…There was no suggestion of modulation of regulatory effects by altering CD4 + CD25 + FoxP3 + T cell numbers (91). Overexpression of galectin-1 in T cells promotes the activation of hepatic stellate cells that contribute to tolerance (92).…”

Understanding, predicting and achieving liver transplant tolerance: from bench to bedside

“…Galectin 1, an endogenous lectin that is expressed in lymphoid organs, substantially prolongs the survival of liver allografts from mouse donors treated with the haematopoietic growth factor FMS-like tyrosine kinase 3 ligand (FLT3L) (which contain markedly increased numbers of myeloid APCs) by inducing T cell apoptosis within the grafts and by suppressing T H 1 and T H 17 cell responses, suggesting that galectin 1 might also have a vital regulatory role in prolonging liver allograft survival 170 . It seems that overexpression of galectin 1 by T cells might promote the activation of HSCs to reduce the inflammatory response and to potentially contribute to restoration of transplant tolerance 171 . Thus, on the basis of extensive in vitro and experimental animal data, it seems that T cell tolerance to liver allografts might be driven by multiple, possibly parallel, molecular mechanisms.…”

The Role of Galectins in Chronic Lung Allograft Dysfunction

“…Gal-1 has been demonstrated to play a negative prognostic role in several conditions, including cancer and fibrotic processes [ 23 , 24 ]. In transplantation, Gal-1 has shown to participate to hepatic graft tolerance and has been postulated it can be implicated in the inhibition of dendritic cells-mediated allogeneic T cell stimulation and survival and Th1/Th17 production [ 19 , 25 , 26 ]. It is also implicated in the dysregulation of the ERK/MAPK pathway [ 12 ] and plays its major function of immunomodulation determining the reduction of INF-gamma and inducing IL5 and IL10 production under inflammatory conditions [ 17 ] thus participating to neutrophil homeostasis [ 27 ].…”