Fig 2: GITRL depletion in liver progenitor cells decreased the proportions of CD8+ lymphocytes and GITR+CD8+ lymphocytes.A Representative flow cytometry images and statistical quantification of the proportion of GITR+ cells among the liver-infiltrating CD45+CD3 – cells and CD45+CD3+ cells. B Representative flow cytometry images of the proportion of CD4+GITR+ cells among the liver-infiltrating CD45+CD3+ lymphocytes. Statistical quantification of the percentage of CD4+ cells among the CD45+CD3+ cells and GITR+ cells among CD45+CD3+CD4+ cells. C Representative flow cytometry images of the proportion of CD8+GITR+ cells among the liver-infiltrating CD45+CD3+ lymphocytes. Statistical quantification of the percentage of CD8+ cells among the CD45+CD3+ cells and GITR+ cells among CD45+CD3+CD8+ cells.

Fig 3: GITR and GITRL participate in the interaction of CD8+ T lymphocytes and liver progenitor organoids.A Representative flow cytometry images of the proportion of CD8+ T lymphocytes before and after magnetic sorting from the nonparenchymal cells. B Experimental design strategy of the coculture system of CD8+ T lymphocytes and liver progenitor organoids. C The mRNA transcript levels of EpCAM, Sox9, ALB, HNF4α, Axin1, and Fzd1 in liver progenitor organoids cocultured with CD8+ T lymphocytes with or without GITR antibodies. D The mRNA transcript levels of TNFα and TGF-β2 in CD8+ T lymphocytes cocultured with Sox9Cre-ERRosaTdTomatoTnfsf18+/+ or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids. E Schematic representation of the effect of GITR and GITRL on hepatic progenitor cells and CD8+ T lymphocytes in CDE mice.

Fig 4: GITRL suppresses the differentiation of liver progenitor cells into hepatocytes, and GITR further hinders this process by reducing the Wnt/β-catenin pathway.A Representative bright-field microscopy images or EpCAM immunofluorescence images of the liver progenitor organoids from Sox9Cre-ERRosaTdTomatoTnfsf18+/+ mice or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox mice. B The mRNA transcript levels of GITRL, EpCAM, PCNA, Cyclin D, CK19, AFP, and ALB in the Sox9Cre-ERRosaTdTomatoTnfsf18+/+ or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids. C The mRNA transcript levels of EpCAM and ALB in the GITR-Fc-exposed Sox9Cre-ERRosaTdTomatoTnfsf18+/+ or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids. D Principal component analysis (PCA) of GITR-Fc- or IgG-exposed Sox9Cre-ERRosaTdTomatoTnfsf18+/+ or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids. E GSEA of GITR-Fc-exposed Sox9Cre-ERRosaTdTomatoTnfsf18+/+ liver progenitor organoids v.s. their IgG-exposed organoids and GITR-Fc-exposed Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids v.s. their IgG-exposed organoids. F GSEA revealed suppression of Wnt/β-catenin signalling in GITR-Fc-exposed Sox9Cre-ERRosaTdTomatoTnfsf18+/+ liver progenitor organoids v.s. their IgG-exposed organoids. G The mRNA transcript levels of Axin1, Fzd1, and Skp2 in the GITR-Fc-exposed Sox9Cre-ERRosaTdTomatoTnfsf18+/+ or Sox9Cre-ERRosaTdTomatoTnfsf18flox/flox liver progenitor organoids and their IgG-exposed control organoids.