TY - JOUR
T1 - β-adrenergic and fibroblast growth factor receptors induce neuronal process outgrowth through different mechanisms
AU - Kwon, John H.
AU - Vogt Weisenhorn, Daniela M.
AU - Downen, Martha
AU - Ruan, Kesan
AU - Roback, Linda
AU - Joshi, Harish
AU - Wainer, Bruce H.
N1 - Copyright:
Copyright 2007 Elsevier B.V., All rights reserved.
PY - 1998
Y1 - 1998
N2 - The mechanisms that initiate and direct neuronal process formation remain poorly understood. We have recently described a neuronal progenitor cell line, AS583-8.E4.22 (AS583-8) which undergoes neurite formation in response to β2-adrenergic and basic fibroblast growth factor (bFGF) receptor activation. In the present study, a comparison of these responses revealed that isoproterenol (ISO), a β-adrenergic receptor agonist, induces multiple, highly branched processes within 30 min while bFGF induces fewer, unbranched processes within 24 h. In contrast to the ISO response, bFGF induces mitogen-activated protein kinase activation and c-fos expression in the cell line and results in neurite outgrowth that is dependent on new mRNA and protein synthesis. Two-dimensional isoelectric focusing-sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cytoskeletal preparations revealed different patterns following ISO vs. bFGF exposure suggesting selective changes in protein expression and/or post-translational modifications. Immunoblot analysis of these preparations for β-tubulin, tyrosinated α-tubulin and acetylated α-tubulin also revealed different patterns following each type of treatment. Follow-up confocal microscopy revealed that following ISO, the distribution of tyrosinated tubulin extends to the distal ends of processes whereas acetylated α-tubulin is diminished within distal ends. This pattern has been reported to be associated with enhanced microtubule dynamics, a state in which process outgrowth is facilitated. In contrast, following bFGF treatment the distributions of tyrosinated and acetylated α-tubulin were identical, a state associated with a diminution of microtubule dynamics. These results, a different time course of neurite formation, dependency on new gene expression and differential expression and cellular distribution of major cytoskeleton proteins suggest that neurite outgrowth induced by ISO vs. bFGF is mediated by two distinct intracellular effector mechanisms in AS583-8 cells. In addition, studies, using the differential distribution of post-translational modified α-tubulins in neurites of primary neuronal cultures as marker for the two distinct processes of neurite formation suggest, that similar mechanisms are present in vivo. Therefore, the AS583-8 cell line provides a useful model to study these signalling mechanisms that couple neurotransmitter and growth factor receptor activation to the cytoskeletal changes that mediate neurite formation.
AB - The mechanisms that initiate and direct neuronal process formation remain poorly understood. We have recently described a neuronal progenitor cell line, AS583-8.E4.22 (AS583-8) which undergoes neurite formation in response to β2-adrenergic and basic fibroblast growth factor (bFGF) receptor activation. In the present study, a comparison of these responses revealed that isoproterenol (ISO), a β-adrenergic receptor agonist, induces multiple, highly branched processes within 30 min while bFGF induces fewer, unbranched processes within 24 h. In contrast to the ISO response, bFGF induces mitogen-activated protein kinase activation and c-fos expression in the cell line and results in neurite outgrowth that is dependent on new mRNA and protein synthesis. Two-dimensional isoelectric focusing-sodium dodecyl sulphate-polyacrylamide gel electrophoresis of cytoskeletal preparations revealed different patterns following ISO vs. bFGF exposure suggesting selective changes in protein expression and/or post-translational modifications. Immunoblot analysis of these preparations for β-tubulin, tyrosinated α-tubulin and acetylated α-tubulin also revealed different patterns following each type of treatment. Follow-up confocal microscopy revealed that following ISO, the distribution of tyrosinated tubulin extends to the distal ends of processes whereas acetylated α-tubulin is diminished within distal ends. This pattern has been reported to be associated with enhanced microtubule dynamics, a state in which process outgrowth is facilitated. In contrast, following bFGF treatment the distributions of tyrosinated and acetylated α-tubulin were identical, a state associated with a diminution of microtubule dynamics. These results, a different time course of neurite formation, dependency on new gene expression and differential expression and cellular distribution of major cytoskeleton proteins suggest that neurite outgrowth induced by ISO vs. bFGF is mediated by two distinct intracellular effector mechanisms in AS583-8 cells. In addition, studies, using the differential distribution of post-translational modified α-tubulins in neurites of primary neuronal cultures as marker for the two distinct processes of neurite formation suggest, that similar mechanisms are present in vivo. Therefore, the AS583-8 cell line provides a useful model to study these signalling mechanisms that couple neurotransmitter and growth factor receptor activation to the cytoskeletal changes that mediate neurite formation.
KW - Basic fibroblast growth factor
KW - Cell line
KW - Fibroblast growth factor receptor
KW - Neurite outgrowth
KW - Tubulin
KW - β-adrenergic receptor
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U2 - 10.1111/j.1460-9568.1998.00315.x
DO - 10.1111/j.1460-9568.1998.00315.x
M3 - Article
C2 - 9758148
AN - SCOPUS:0032449461
SN - 0953-816X
VL - 10
SP - 2776
EP - 2789
JO - European Journal of Neuroscience
JF - European Journal of Neuroscience
IS - 9
ER -