Fig. 1: Podocyte B7-1 is upregulated in a variety of glomerular diseases and associates with β-catenin.

A Representative micrographs of B7-1 RNAscope staining and β-catenin immunochemistry staining in human kidney cortical tissue from CKD patients with lupus nephritis class III (LN), and the healthy control was from paracancerous tissue. Arrows indicate positive staining. Bar = 50 μm. B, C Representative micrographs showing the colocalization of B7-1 and α-actinin-4, B7-1 and β-catenin, β-catenin and α-actinin-4 in human kidney biopsy from a patient with LN. Arrows indicate positive staining. Bar = 50 μm. D Urinary B7-1 levels were increased following the disease progression in CKD patients. Patients were grouped according to their estimated glomerular filtration rate (eGFR) (ml/min per 1.73 m²) as indicated. *P < 0.05, **P < 0.01 versus healthy control group. Healthy control (Ctl): n = 10; CKD1: n = 33; CKD2-3: n = 32; CKD4-5: n = 11. E–G Linear regressions showing the correlation between urinary B7-1 and eGFR, urinary albumin-to-creatinine ratio (ACR) or urinary β-2 microglobulin (β2-MG) content in all subjects (n = 86). The spearman correlation coefficient (r) and P value are shown. H Representative images showing B7-1 IF staining (Bar = 20 μm), β-catenin IHC staining (Bar = 25 μm), and TEM micrographs (Bar = 1 μm) in diabetic db/db mice and their genetic control (db/m) mice. White and black Arrows indicate positive staining. Yellow arrow indicates foot process effacement. I Representative micrographs showing the colocalization of B7-1 and α-actinin-4 in db/db mice, Bar = 10 μm. J, K Western blot and quantitative data showing the relative protein levels of B7-1 and β-catenin in kidneys from db/db mice and db/m mice. *P < 0.05, ***P < 0.001 versus db/m mice. L The relative mRNA level of B7-1 in isolated glomerulus and tubule from mice after treatment with adriamycin (ADR) at indicated time points (3, 7 or 14 days). *P < 0.05, **P < 0.01 versus control group. n = 5. M Representative Western blot showing the protein levels of B7-1, Nephrin and Desmin in isolated glomeruli at different time points after ADR injection. Each group contains five biological independent samples from mice. N Representative micrographs showing the co-expression of B7-1 and β-catenin, or B7-1 and Podocalyxin in isolated glomeruli from ADR mice. Arrows indicate the colocalization of B7-1 and β-catenin or podocalyxin. Bar = 10 μm. The full length original western blots for all results are provided in Supplementary File 1.