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

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.