Modulation of the No Secretion in the Pichilan-Activated Murine Macrophage Cell Line, Malu

The mechanism of action of pichilan, a (1->3)-β-D-glucan on nitric oxide production by a murine macrophage cell line, MALU cells, was examined. Different metabolic pathways were investigated in order to understand pichilan-induced NO secretion. We demonstrate in the present paper that neither the acid arachidonic metabolism, the cAMP nor Ca2+ accumulation occured in the pichilan mechanism of action on NO secretion. On the other hand, we observed that a phorbol ester, PMA, modulated the NO secretion. An inhibition of 36% of the NO secretion was observed; consequently, pichilan could regulate the NO secretion by way of the protein kinase C. Furthermore, we demonstrated that TNF production stimulated by pichilan activation induced NO secretion by MALU cells. TNF would be the main modulator of NO secretion by pichilan or LPS-activated MALU cells. Moreover, we can note that pichilan and LPS did not act similarly on nitrite secretion by MALU cells.