IL-6/sIL-6R trans-signalling, but not TNF-alpha induced angiogenesis in a HUVEC and synovial cell co-culture system.
Angiogenesis in synovia is a characteristic of RA patients. We examined whether IL-6 or TNF-alpha induce tubule formation in a co-culture system of fibroblast-like synovial cells from RA patients (RA-FLS) and human umbilical vein endothelial cells (HUVEC). The effects of IL-6 and TNF-alpha on the expression of angiogenic factors in RA-FLS and HUVEC, and the proliferation of HUVEC were also studied. IL-6 + sIL-6R induced tubule formation, whereas IL-6 alone did not. IL-6/sIL-6R-induced tubule formation was completely suppressed by the addition of either anti-IL-6R or anti-VEGF antibody. TNF-alpha did not induce tubule formation. On the contrary, it decreased CD31-positive area compared with the control. IL-6 + sIL-6R augmented VEGF production in RA-FLS, whereas IL-6 alone did not. Anti-IL-6R antibody suppressed IL-6/sIL-6R-induced VEGF production, but not spontaneous VEGF production. In contrast, TNF-alpha did not induce VEGF production from RA-FLS and HUVEC. IL-6 + sIL-6R stimulation of RA-FLS strongly induced mRNA expression of VEGF, but not of other angiogenic factors, such as EGF, bFGF, TGF-beta, IL-1, TNF-alpha and IL-8. Neither IL-6 nor IL-6/sIL-6R promoted HUVEC proliferation, whereas TNF-alpha significantly inhibited VEGF-induced HUVEC proliferation. In conclusion, IL-6/sIL-6R complex showed angiogenic activity via the production of VEGF from RA-FLS, but TNF-alpha was anti-angiogenic in our experimental system.
Hashizume
Misato
M
Product Research Department, Chugai Pharmaceutical Co, Ltd, Gotemba, Shizuoka 412-8513, Japan.
Hayakawa
Naohiko
N
Suzuki
Miho
M
Mihara
Masahiko
M
D001172:Arthritis, Rheumatoid / Q000378:metabolism* / Q000473:pathology; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D004730:Endothelium, Vascular / Q000166:cytology* / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism* / Q000494:pharmacology; D016209:Interleukin-8 / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D019947:Receptors, Interleukin-6 / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013583:Synovial Membrane / Q000378:metabolism / Q000473:pathology*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism* / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D012333:RNA, Messenger; D019947:Receptors, Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; D005346:Fibroblast Growth Factors