DIRECTIONAL NEURITE OUTGROWTH AND AXONAL DIFFERENTIATION OF EMBRYONICHIPPOCAMPAL-NEURONS ARE PROMOTED BY A NEURITE OUTGROWTH DOMAIN OF THEB2-CHAIN OF LAMININ

Molecular cues involved in directional neurite outgrowth and axonal di fferentiation of embryonic hippocampal neurons were studied on substra tes coated in a striped 5 mu m pattern with synthetic peptides from a neurite outgrowth (RDIAEIIKDI, P1543) and cell attachment (CDPGYIGSR, P364) domain of the B2- and B1-chains of laminin, respectively. Both p eptides supported neuronal attachment, but only the B2-chain-derived P 1543 promoted expression of a mature neuronal phenotype. Directional n eurite outgrowth and axonal differentiation of embryonic hippocampal n eurons were selectively induced by striped substrates of the B2-chain- derived P1543. Axonal differentiation was determined by expression of a phosphorylated epitope of the 200 kDa neurofilament protein in the l onger ''axonal'' neurite of the bipolar embryonic hippocampal neurons. Ethanol (100 mM), a neuroactive compound known to delay neuronal deve lopment, impaired both directional neurite outgrowth and expression of a phosphorylated epitope of the 200 kDa neurofilament protein on a pa tterned P1543 substratum. The present results provide direct evidence that a 10 amino acid peptide (P1543), derived from a neurite outgrowth domain of the B2-chain of laminin, may be an axonal guidance and diff erentiation factor for embryonic hippocampal neurons in vitro. Publish ed by Elsevier Science Ltd.