Transforming growth factor-beta 1 stimulates macrophage urokinase expression and release of matrix-bound basic fibroblast growth factor.
Macrophage expression of urokinase-type plasminogen activator (uPA) appears to play a role in their release of matrix-bound basic fibroblast growth factor (bFGF) and transforming growth factor-beta (TGF-beta). In experiments reported here, we have examined the potential regulatory effects of bFGF and TGF-beta 1 on macrophage uPA expression. TGF-beta 1 stimulated in a dose- and time-dependent manner the expression of secreted membrane and intracellular uPA activities by a macrophage cell line (RAW264.7). When examined at similar concentrations, bFGF had little effect, and interleukin-1 alpha, tumor necrosis factor-alpha, and monocyte colony stimulating factor had no effect on macrophage uPA expression. Exposure of macrophages to TGF-beta 1 led to a rapid and sustained increase in the steady-state levels of uPA mRNA that was independent of de novo protein synthesis and was completely inhibited by actinomycin D. However, the TGF-beta 1-induced increase in uPA mRNA was largely unaffected by subsequent incubation of cells with actinomycin D. The protein kinase C inhibitor H7 markedly reduced the ability of TGF-beta 1 to stimulate expression of uPA activity. Likewise, okadaic acid and microcystin, inhibitors of serine/threonine phosphatases, potentiated the ability of TGF-beta 1 to upregulate macrophage uPA expression. TGF-beta 1 primed cells converted nearly all added plasminogen to plasmin and expressed sixfold more membrane-bound plasmin than control cells. Preincubation of TGF-beta 1 with either serum or methylamine-modified alpha 2-macroglobulin did not affect its ability to induce macrophage uPA expression. When control and TGF-beta 1-primed macrophages were cultured on matrices containing bound 125I-bFGF, their release of 125I-bFGF was increased five and tenfold, respectively, in the presence of plasminogen. The ability of TGF-beta to induce macrophage uPA expression and the plasmin-dependent release of matrix-bound bFGF may provide an indirect mechanism by which TGF-beta stimulates angiogenesis.
Falcone
D J
DJ
Department of Pathology, Cornell Medical College, New York, New York.
McCaffrey
T A
TA
Haimovitz-Friedman
A
A
Garcia
M
M
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D000818:Animals; D002460:Cell Line; D003609:Dactinomycin / Q000494:pharmacology; D004357:Drug Synergism; D004988:Ethers, Cyclic / Q000494:pharmacology; D005109:Extracellular Matrix / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism* / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology; D008264:Macrophages / Q000378:metabolism*; D008744:Methylamines / Q000494:pharmacology; D051379:Mice; D052998:Microcystins; D019319:Okadaic Acid; D010456:Peptides, Cyclic / Q000494:pharmacology; D010879:Piperazines / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D012333:RNA, Messenger / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D014568:Urokinase-Type Plasminogen Activator / Q000235:genetics* / Q000378:metabolism; D000511:alpha-Macroglobulins / Q000494:pharmacology
D004988:Ethers, Cyclic; D007546:Isoquinolines; D008744:Methylamines; D052998:Microcystins; D010456:Peptides, Cyclic; D010879:Piperazines; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D000511:alpha-Macroglobulins; D016222:Fibroblast Growth Factor 2; D003609:Dactinomycin; D019319:Okadaic Acid; C078588:microcystin; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; C027451:methylamine; D011493:Protein Kinase C; D014568:Urokinase-Type Plasminogen Activator