Nitric oxide mediates laminin-induced neurite outgrowth in PC12 cells

Laminin is a potent stimulator of neurite outgrowth in a variety of primary neurons and neuronal cell lines. Here, we investigate the role of nitric o xide in the signaling mechanism of laminin-mediated neurite outgrowth in th e PC12 cell line. Within 8 s of exposure to laminin, PC12 cells produce nit ric oxide. Peak laminin-induced nitric oxide levels reach 8 nM within 12 s of exposure to laminin and constitutive nitric oxide production is sustaine d for 1 min. A neurite outgrowth promoting synthetic peptide (AG73), derive d from the laminin-l-alpha globular domain, also stimulated nitric oxide re lease. The nitric oxide synthase inhibitor, 1-NAME, prevents the formation of nitric oxide and here, 1-NAME inhibited both laminin-mediated and AG73-m ediated neurite outgrowth by 88 and 95%, respectively. In contrast, C16, a synthetic peptide derived from the laminin-1-gamma chain, is shown here to promote PC12 cell attachment, but not neurite outgrowth. Interestingly, the C16 peptide did not activate nitric oxide release, suggesting that laminin -induced nitric oxide release in PC12 cells is associated only with neurite outgrowth promoting laminin domains and signals. In addition, the data her e show that the nitric oxide released by PC12 cells in response to laminin is required as a part of the mechanism of laminin-mediated neurite outgrowt h. (C) 2000 Academic Press.