Figure 1. FRCs and vascular ECs express autotaxin in an LTβR-signaling-dependent manner.
(A) Representative dot plot of the CD45- stromal cells in LNs. CD45- cells were divided by CD31 and gp38 expression into FRCs (gp38+ CD31-), lymphatic endothelial cells (LECs; gp38+ CD31+), blood endothelial cells (BEC; gp38-CD31+), and double-negative cells. Numbers indicate the frequency of cells in each gate. (B) Enpp2/Autotaxin expression in stromal LN fractions, analyzed by quantitative RT-PCR. (C) ATX expression examined by immunoelectron microscopy; arrow indicates positive signals in an FRC. C: collagen fibers; L: lymphocytes. Bar, 1 μm. (D) Enpp2 in CD45- EYFP+ cells in LNs and the spleen of Ccl19-Cre x R26-EYFP mice. (E) Effect of LTβR signaling on Enpp2 expression in FRCs and BECs. LTβR signaling was blocked by injecting 100 μg of recombinant LTβR-Fc or an isotype control into adult mice intraperitoneally weekly for 4 weeks. The FRCs and BECs were then sorted, and the indicated gene expressions were analyzed by quantitative PCR. Data are representative of three (A, B, D) or two (C, E) independent experiments (n = 3 per group). Differences between groups were evaluated by Student’s t-test. *P < 0.05; **P < 0.005; ***P < 0.0005.