Electrical signals elicited by integrin interaction with ECM components and their role in neurite outgrowth were studied in two clones (N1 and N7) isolated from 41A3 murine neuroblastoma cell line. Although the two clones similarly adhered to fibronectin (FN) and vitronectin (VN), this adhesion induced neurite outgrowth in N1 but not in N7 cells. Patch clamp recordings in whole cell configuration showed that, upon adhesion to FN or VN but not to platelet factor 4 (PF4), N1 cells undergo a marked (is-approximately-equal-to 20 mV) hyperpolarization of the resting potential (V(rest)) that occurred within the first 20 min after cell contact with ECM, and persisted for approximately 1 h before reverting to the time zero values. This hyperpolarization was totally absent in N7 cells. A detailed analysis of the molecular mechanisms involved in N1 and N7 cell adhesion to ECM substrata was performed by using antibodies raised against the FN receptor and synthetic peptides variously competing with the FN or VN binding to integrin receptors (GRGDSP and GRGESP). Antibodies, as well as GRGDSP, abolished adhesion of N1 and N7 clones to FN and VN, revealing a similar implication of integrins in the adhesion of these clones to the ECM proteins. However, these anti-adhesive treatments, while ineffective on V(rest), of N7 cells, abolished in N1 cells the FN- or VN-induced hyperpolarization and neurite outgrowth, that appeared therefore strictly associated and integrin-mediated phenomena. The nature of this association was deepened through a comparative analysis of the integrin profiles and the ion channels of N1 and N7 cells. The integrin immunoprecipitation profile resulted very similarly in the two clones, with only minor differences concerning the alphaV containing complexes. Both clones possessed Ca2+ and K+ delayed rectifier (K(DR)) channels, while only N1 cells were endowed with inward rectifier K+ (K(IR)) channels. The latter governed the V(rest), and, unlike K(DR) channels, were blocked by Ba2+ and Cs+. By moving patched cells in contact with FN-coated beads, it was shown that K(IR) channel activation was responsible for the FN-mediated hyperpolarization of V(rest). Treatment with Pertuxis toxin (PTX) abolished this hyperpolarization and neurite outgrowth, indicating that a G protein is interposed between integrins and K(IR) channels and that the activation of these channels is required for neuritogenesis. In fact, the block of K(IR) channels by Cs+ abolished both hyperpolarization and neurite outgrowth, provided that the cation was supplied during the first two hours after N1 cell contact with FN. This Cs+-sensitive commitment time for neuritogenesis coincided with the time length of the FN-induced hyperpolarization.

Integrin-mediated neurite outgrowth in neuroblastoma cells depends on the activation of potassium channels / A. ARCANGELI; A. BECCHETTI; A. MANNINI; G. MUGNAI; P. DE FILIPPI; G. TARONE; M.R. DEL BENE; E. BARLETTA; E. WANKE; M. OLIVOTTO. - In: THE JOURNAL OF CELL BIOLOGY. - ISSN 0021-9525. - ELETTRONICO. - 122:(1993), pp. 1131-1143. [10.1083/jcb.122.5.1131]

Integrin-mediated neurite outgrowth in neuroblastoma cells depends on the activation of potassium channels.

ARCANGELI, ANNAROSA;MANNINI, ANTONELLA;MUGNAI, GABRIELE;BARLETTA, EMANUELA;OLIVOTTO, MASSIMO
1993

Abstract

Electrical signals elicited by integrin interaction with ECM components and their role in neurite outgrowth were studied in two clones (N1 and N7) isolated from 41A3 murine neuroblastoma cell line. Although the two clones similarly adhered to fibronectin (FN) and vitronectin (VN), this adhesion induced neurite outgrowth in N1 but not in N7 cells. Patch clamp recordings in whole cell configuration showed that, upon adhesion to FN or VN but not to platelet factor 4 (PF4), N1 cells undergo a marked (is-approximately-equal-to 20 mV) hyperpolarization of the resting potential (V(rest)) that occurred within the first 20 min after cell contact with ECM, and persisted for approximately 1 h before reverting to the time zero values. This hyperpolarization was totally absent in N7 cells. A detailed analysis of the molecular mechanisms involved in N1 and N7 cell adhesion to ECM substrata was performed by using antibodies raised against the FN receptor and synthetic peptides variously competing with the FN or VN binding to integrin receptors (GRGDSP and GRGESP). Antibodies, as well as GRGDSP, abolished adhesion of N1 and N7 clones to FN and VN, revealing a similar implication of integrins in the adhesion of these clones to the ECM proteins. However, these anti-adhesive treatments, while ineffective on V(rest), of N7 cells, abolished in N1 cells the FN- or VN-induced hyperpolarization and neurite outgrowth, that appeared therefore strictly associated and integrin-mediated phenomena. The nature of this association was deepened through a comparative analysis of the integrin profiles and the ion channels of N1 and N7 cells. The integrin immunoprecipitation profile resulted very similarly in the two clones, with only minor differences concerning the alphaV containing complexes. Both clones possessed Ca2+ and K+ delayed rectifier (K(DR)) channels, while only N1 cells were endowed with inward rectifier K+ (K(IR)) channels. The latter governed the V(rest), and, unlike K(DR) channels, were blocked by Ba2+ and Cs+. By moving patched cells in contact with FN-coated beads, it was shown that K(IR) channel activation was responsible for the FN-mediated hyperpolarization of V(rest). Treatment with Pertuxis toxin (PTX) abolished this hyperpolarization and neurite outgrowth, indicating that a G protein is interposed between integrins and K(IR) channels and that the activation of these channels is required for neuritogenesis. In fact, the block of K(IR) channels by Cs+ abolished both hyperpolarization and neurite outgrowth, provided that the cation was supplied during the first two hours after N1 cell contact with FN. This Cs+-sensitive commitment time for neuritogenesis coincided with the time length of the FN-induced hyperpolarization.
1993
122
1131
1143
Goal 3: Good health and well-being for people
A. ARCANGELI; A. BECCHETTI; A. MANNINI; G. MUGNAI; P. DE FILIPPI; G. TARONE; M.R. DEL BENE; E. BARLETTA; E. WANKE; M. OLIVOTTO
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Utilizza questo identificatore per citare o creare un link a questa risorsa: https://hdl.handle.net/2158/309959
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