Fig. 5: Macrophage deficiency of LXN promotes PD-L2 expression by enhancing JAK1/STAT3 activity.

A Immunoblotting shows that LXN interacts with JAK1 in BMDMs. B Representative co-localization of LXN and JAK1 in BMDMs by immunofluorescence. Scale bars = 20 µm. C RAW264.7 cells were transfected with pStat3-TA-luc, Myc-JAK1 and Flag-LXN plasmid as indicated, and induction of luciferase activity was determined. Data are representative of three independent experiments. **P < 0.01. D Western blot shows that LXN deficiency increases the expression of PD-L2 and phosphorylation of JAK1/STAT3 in mice macrophages. E Representative the expression of PD-L2 in macrophages from WT and LXN KO mice by immunofluorescence. The red arrow indicates that PD-L2 is expressed on the cell surface. Scale bars = 20 µm. F Macrophages from WT and LXN KO mice treated with solcitinib for 24 h, the expression of PD-L2 and the activity of JAK1/STAT3 were determined by Western blot (left). Quantitative analysis of western blot was shown (right). Data are representative of three independent experiments. **P < 0.01, ***P < 0.001, n.s. no significance. G Representative the DNA-binding activity of STAT3 in WT and LXN KO macrophage by EMSA assay. *P < 0.05. H Representative the binding activity of STAT3 to PD-L1/2 promoter in WT and LXN KO macrophages by ChIP assay. I Representative the binding activity of STAT3 to PD-L1/2 promoter in RAW 264.7 cells transfected with Flag LXN. Data are representative of three independent experiments. **P < 0.01, n.s. no significance.