T. Naitoh et al., Tumor necrosis factor-alpha is induced through phorbol ester- and glycatedhuman albumin-dependent pathway in THP-1 cells, CELL SIGNAL, 13(5), 2001, pp. 331-334
Tumor necrosis factor-alpha (TNF-alpha) is involved in insulin resistance.
Since the fact that peroxisome proliferator-activated receptor gamma (PPAR
gamma) ligands inhibit the induction of TNF-alpha by phorbol ester, but not
by lipopolysaccharide (LPS), suggests two pathways to induce TNF-alpha, we
investigated the mechanisms of glycated human albumin (GHA)- or phorbol es
ter-induced TNF-alpha in THP-1 cells. GHA induced TNF-alpha release in diff
erentiated THP-1 cells, while phorbol ester induced TNF-alpha release in un
differentiated cells but did not induce TNF-alpha in differentiated cells.
Forskolin (adenylate cyclase activator) affected more the GHA-induced TNF-a
lpha release than the phorbol 12-myristate 13-acetate (PMA)-induced one in
undifferentiated cells. Staurosporine [protein kinase-C (PK-C) inhibitor] a
nd PD98059 [mitogen-activated protein kinase inhibitor (MAPK)] only partial
ly inhibited GHA-induced TNF-alpha. Catalase completely inhibited GHA-induc
ed TNF-alpha release; however. superoxide dismutase (SOD) had no effect. Th
ese results suggest at least two pathways to induce NTF-alpha (phorbol este
r- and GHA-dependent ways) and that GHA-induced TNF-alpha release is throug
h predominantly catalase-dependent way in differentiated THP-1 cells. (C) 2
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