Regulation of tumour necrosis factor-α processing by a metalloproteinase inhibitor

Abstract

Tumour necrosis factor-alpha (TNF-alpha) is a potent pro-inflammatory agent produced primarily by activated monocytes and macrophages. TNF-alpha is synthesized as a precursor protein of M(r) 26,000 (26K) which is processed to a secreted 17K mature form by cleavage of an Ala-Val bond between residues 76-77. The enzyme(s) responsible for processing pro-TNF-alpha has yet to be identified. Here, we describe the capacity of a metalloproteinase inhibitor, GI 129471, to block TNF-alpha secretion both in vitro and in vivo. The inhibition is specific to TNF-alpha; the production of other secreted cytokines, such as the interleukins IL-1 beta, IL-2, or IL-6, is not inhibited. The mechanism of inhibition occurs at a post-translational step in TNF-alpha production. Our data suggest that TNF-alpha processing is mediated by a unique Zn2+ endopeptidase which is inhibited by GI 129471 and would represent a novel target for therapeutic intervention in TNF-alpha associated pathologies.

Stimulation of Matrix Metalloproteinase-9 Expression in Human Fibrosarcoma Cells by Synthetic Matrix Metalloproteinase Inhibitors

“…7). A similar stimulation of IL-1β secretion by synthetic MMPIs has been previously documented by others [27,58,59] and results most probably from the inhibition of an MMP-mediated IL-1β degradation [60]. In order to assess whether this elevated IL-1β concentration could mediate MMP-9 overexpression, HT1080 cells, treated or not with GI129471 (1 µM), were supplemented with increasing concentrations of recombinant human IL-1β (0-5 ng/ml) and 48-h conditioned media were analyzed by gelatin zymography.…”

“…All culture reagents were purchased from Gibco-Life Technologies (Merelbeke, Belgium). [26,27], BB-94 [26], and AG3340 [28] are broad-spectrum hydroxamic acid based synthetic MMPIs (all these inhibitors were kindly provided by Roche Diagnostics and synthesized according to the PCT Patent Applications WO 90/05719 [GI129471 and BB-94] and WO 95/04735 [AG3340]). Recombinant human TIMP-1 (rTIMP-1) was a gift of Prof. G. Murphy (School of Biological Sciences, University of East Anglia, Norwich, UK).…”

Matrix metalloproteinases in neuroinflammation

“…TNF-␣ is bound to the membrane as an inactive 26-kDa form and is processed to an active 17-kDa entity by TACE. Hydroxymate-based metalloproteinase inhibitors blocked the processing of inactive TNF-␣ to the active form (McGeehan et al, 1994;Gearing et al, 1994). The growing ADAMs family includes enzymes that cleave a number of ECM molecules; they also act as "sheddases" in removing ectodomain molecules from the cell surface.…”

Developmental expression of MMP‐9 (gelatinase B) mRNA in mouse embryos

“…MMP-9, as well as many of the other MMPs, is capable of processing TNF-a (although which species is active in vitro is not known). This suggests that MMPs may have important functions other than or in addition to the degradation of extracellular matrix components (Gearing et al, 1994;McGeehan et al, 1994). MMP-9, like other members of the MMP family, is secreted as a proenzyme, requires zinc for activity, and can be inhibited by naturally occurring inhibitors called tissue inhibitors of metalloproteinases (TIMP) (Birkedal-Hansen et al, 1993;Khokha and Denhardt, 1989;Matrisian, 1990;Murphy and Docherty, 1992;Stetler-Stevenson et al, 1993).…”