(A) CM from PDGF-D-treated fibroblasts ((PDGF-D) CM) dramatically impaired the integrity of the lymphatic endothelial barrier, more effectively than VEGF-C and VEGF-A. This effect was only partially counteracted by the concomitant treatment with αVEGFR2 ((PDGF-D) CM + αVEGFR2), but completely abrogated by the supplementation with αVEGFR3 ((PDGF-D) CM + αVEGFR3) or with bevacizumab ((PDGF-D) CM + Bev) or anti-VEGF-C ((PDGF-D) CM + αVEGF-C), as well as by PDGFRβ antagonism in PDGF-D-treated fibroblasts ((PDGF-D + IM) CM). (B) In TrEM experiments, CM from PDGF-D-treated fibroblasts ((PDGF-D) CM) enabled the CCA cell line EGI-1-EGFP to cross the LEC monolayer (similar to VEGF-A and VEGF-C), an effect blunted by the treatment of PDGF-D-stimulated fibroblasts with PDGFRβ antagonist ((PDGF-D + IM) CM), or with bevacizumab ((PDGF-D) CM + Bev) or anti-VEGF-C ((PDGF-D) CM + αVEGF-C), or by the treatment of LEC with αVEGFR3 ((PDGF-D) CM + αVEGFR3), but not with αVEGFR2 ((PDGF-D) CM + αVEGFR2). For TEER, n=4–15 experiments in duplicate. For TrEM, n=3–4; *p<0.05 vs Ctrl, **p<0.01 vs Ctrl, ^p<0.05 vs (PDGF-D) CM, ^^p<0.01 vs (PDGF-D) CM, using two-tail t test.