Enhancement of human hepatocyte growth factor production by interleukin- 1α and -1β and tumor necrosis factor-α by fibroblasts in culture

Human hepatocyte growth factor (hHGF) was first purified from plasma of patients with fulminant hepatic failure (Gohda, E., Tsubouchi, H., Nakayama, H., Hirono, S., Sakiyama, O., Takahashi, K., Miyazaki, H., Hashimoto, S., and Daikuhara, Y. (1988) J. Clin. Invest. 81, 414-419) and is now identified to be the same protein as the scatter factor (Weidner, K. M., Arakaki, N., Hartmann, G., Vandekerckhove, J., Weingart, S., Rieder, H., Fonatsch, C., Tsubouchi, H., Hishida, T., Daikuhara, Y., and Birchmeier, W. (1991) Proc. Natl. Acad. Sci. U. S. A. 88, 7001-7005) and tumor cytotoxic factor (Shima, N., Nakao, M., Ogaki, F., Tsuda, E., Murakami, A., and Higashio, K. (1991) Biochem. Biophys. Res. Commun. 180, 1151-1158), and it is known to be produced by fibroblasts in culture. Here we report that inflammatory cytokines such as interleukin-1 (IL-1) and tumor necrosis factor (TNF) stimulate production of hHGF from human embryonic lung fibroblasts, MRC-5, and human gingival fibroblasts, GF-5. Recombinant human IL-1α (rhIL-1α) and recombinant human TNF-α (rhTNF-α) increased hHGF levels in culture supernatants of MRC-5 and GF-5 cells dose-dependently as determined by an enzyme-linked immunosorbent assay for hHGF. The half-maximal stimulatory concentrations of rhIL-1α and rhTNF-α were about 1 ng/ml and 10 units/ml, respectively. rhIL-1β showed almost the same effect as IL-1α on stimulation of production of immunoreactive hHGF from the two cell lines. However, rhIL- 6 failed to show the stimulatory effect on hHGF production by the cells in the range of 2-200 units/ml. Human interferon-β and -γ also did not show the stimulatory activity. Stimulation of hHGF production was observed 6-12 h after addition of rhIL-1α or rhTNF-α and lasted at least 48 h, and the observed stimulation of hHGF production by cytokines was suppressed by addition of corresponding antiserum. hHGF mRNA levels of MRC-5 cells increased by addition of rhIL-1α and rhTNF-α in a dose-dependent manner as determined by Northern blot analysis using cDNA for hHGF as a probe. In addition, results from nuclear run-off transcription experiments showed that the two cytokines regulated increasing hHGF gene expression at transcriptional levels rather than a change in mRNA stability. These observations indicate that the inflammatory cytokines modulate the production and secretion of hHGF by fibroblasts and may play an important role for tissue repair and regeneration.