Tumour
necrosis factor-alpha (
TNF-alpha) is an inflammatory
cytokine produced by circulating monocytes and resident macrophages during acute
inflammation and is responsible for a diverse range of signalling events within cells, leading to
necrosis or apoptosis. The
biologic activities of TNF are mediated by two receptors
TNFR1 and
TNFR2, although a lot of studies demonstrated that most of the
biological activities of
TNF-alpha are mediated through
TNFR1. In the present study, we want to evaluate the role of
TNF-alpha on regulation of in vitro models of
inflammation. In particular we used peritoneal macrophages, from TNF-alphaR1 knock out and TNF-alphaR1 wild-type mice, stimulated with LPS 10 microg/ml and IFN-gamma 100 U/ml. Our results showed that the deletion of TNF-alphaR1 gene significantly reduced the degree of (i) MAPK activation, (ii)
IkappaB-alpha degradation, (iii) phosphorylation of Ser536 on the
NF-kappaB subunit p65 and (iv) iNOS and COX-2 expression. In addition, to confirm the pivotal role of
TNF-alpha on regulation of peritoneal macrophages
inflammation, we have also investigated the protective effects of
infliximab, a
TNF-alpha chimeric mouse/human
IgG1 antibody against
TNF-alpha. As shown in the present study, the cell incubation with
infliximab (0.1 microg/ml, 1 microg/ml and 10 microg/ml) significantly leads to a concentration-dependent inhibition of the inflammatory mediators above described. In conclusion, our study demonstrates that pharmacological and genetic inhibition of the TNF/
TNFR1 binding reduce the degree of macrophages
inflammation caused by LPS/IFN-gamma stimulation.