A MATRIX METALLOPROTEINASE INHIBITOR PREVENTS PROCESSING OF TUMOR-NECROSIS-FACTOR-ALPHA (TNF-ALPHA) AND ABROGATES ENDOTOXIN-INDUCED LETHALITY

Excessive tumor necrosis factor alpha (TNF alpha) production in respon se to Gram-negative bacteremia or endotoxemia can often lead to hypote nsion, shock, and increased mortality. Current approaches used to bloc k the deleterious effects of exaggerated TNF alpha production rely on monoclonal antibodies or immunoadhesins that bind TNF alpha and thus p revent the interaction with its cellular receptors. This report examin es whether a previously described inhibitor of matrix metalloproteinas es, GM-6001, can inhibit TNF alpha processing and release and attenuat e endotoxin-induced mortality. In human peripheral blood mononuclear c ells stimulated in vitro with I mu g/mL endotoxin, GM-6001 at concentr ations >5 mu g/mL blocked release of TNF alpha, but did not affect the release of either IL-1 beta or IL-6. GM-6001 also inhibited the relea se of soluble TNF receptor (p75) from peripheral blood mononuclear cel ls stimulated with endotoxin and/or TNF alpha. To confirm the role of secreted TNF alpha in endotoxic shock-induced mortality, C57BL/6 mice were challenged with either endotoxin alone (500 mu g/mouse) or endoto xin (100 ng/mouse) plus D-galactosamine (8 mg/mouse). GM-6001 pretreat ment(100 mg/kg) significantly attenuated the 90-minute plasma TNF alph a response in both models and improved survival in mice treated with l ow-dose endotoxin plus D-galactosamine. However, plasma IL-1 beta and IL-6 concentrations al 90 min after endotoxin treatment were unaffecte d by GM-6001 following lethal endotoxin challenge, confirming the in v ivo specificity of this matrix metalloproteinase inhibitor for TNF alp ha processing. These findings demonstrate that a novel inhibitor of ma trix metalloproteinases can prevent the release of TNF alpha both in v itro and in vivo, and can abrogate the harmful sequelae of endotoxemic shock.