TY - JOUR
T1 - Soluble or bound laminin elicit in human neuroblastoma cells short- or long-term potentiation of a K+ inwardly rectifying current
T2 - Relevance to neuritogenesis
AU - Arcangeli, Annarosa
AU - Faravelli, Laura
AU - Bianchi, Laura
AU - Rosati, Barbara
AU - Gritti, Angela
AU - Vescovi, Angelo
AU - Wanke, Enzo
AU - Olivotto, Massimo
N1 - Funding Information:
The authors are indebted to Prof. A. Fonnesu, Chairman of the Istituto di Patologia Generale, Universith di Firenze, and to Prof. A. Ferroni, Chairman of the Dipartimento di Fisiologia e Biochimica Generali, Universith di Milano, for their support and advice. The critical reading of the manuscript by Guido Tarone (University of Torino, Italy) and the shipping of the anti-integrin antibodies (BV7) is acknowledged. Thanks are also due to Dr. C. Damsky, from the University of California, San Francisco, USA, for kindly gifting the anti p,- integrin antibodies (AIIB2), and to Dr. A. Zaza, from the Dipartimento di Fisiologia e Biochimica Generali, Universith di Milano, for kindly gifting the antiarrhythmic drug E4031. We also thank Marco Cutri for the precious technical assistance. This work was supported by grants from the Asso-ciazione Italiana per la Ricerca sul Cancro (AIRC), from the Consiglio Nazionale delle Ricerche (CNR; Finalized Project ACRO), from the Minister0 della Universith e della Ricerca Scientifica e Tecnologica (MURST), and from the Associazione Italiana contro le Leucemie (AIL), Firenze.
Copyright:
Copyright 2004 Elsevier Science B.V., Amsterdam. All rights reserved.
PY - 1996
Y1 - 1996
N2 - Changes in the resting potential (VREST) and in the underlying ionic conductances were measured by the patch-clamp technique in SH-SY5Y human neuroblastoma cells exposed to substrate-bound or soluble Laminin (bLN; sLN), as compared to integrin-independent substrates (polylysine (PL); bovine serum albumin (BSA)). While PL and BSA were ineffective, both forms of LN caused an early (5-15 min) activation of a peculiar type of Inwardly Rectifying K+ current (IIR) characterised by a voltage-dependent inactivation in the range of membrane potentials around -50/0 mV. IIR was blocked by Cs+ ions and by the antiarrhythmic drug E-4031, a specific inhibitor of the HERG-codified channels. In cells adherent to bLN, IIR potentiation (85%) persisted for 90-120 min and was accompanied by a similar, but transient, increase in the leakage conductance (GL). Successively, the persistence of a high IIR conductance and the decrease of GL progressively bring VREST from -12 to ∼ -30 mV in about 120 min. On the other hand, in cells adherent to PL, exposure to sLN produced a similar but not persistent activation of IIR, without any increase in GL. this caused a rapid, transient hyperpolarisation of VREST. The effects of bLN and sLN were mimicked by antibodies raised against the integrin β1 subunit, suggesting a specific integrin-mediated mechanism. In fact, when bound to the culture dishes, these antibodies simultaneously activated the IIR and GL, whereas in soluble form they only activated IIR. Cells adherent to bLN emitted neurites, a process impaired by the block of IIR by E-4031 and Cs-. On the whole data suggest that the integrin-mediated activation of IIR plays a crucial role in the commitment to neuritogenesis of neuroblastoma cells, independently on the effects of this activation on VREST.
AB - Changes in the resting potential (VREST) and in the underlying ionic conductances were measured by the patch-clamp technique in SH-SY5Y human neuroblastoma cells exposed to substrate-bound or soluble Laminin (bLN; sLN), as compared to integrin-independent substrates (polylysine (PL); bovine serum albumin (BSA)). While PL and BSA were ineffective, both forms of LN caused an early (5-15 min) activation of a peculiar type of Inwardly Rectifying K+ current (IIR) characterised by a voltage-dependent inactivation in the range of membrane potentials around -50/0 mV. IIR was blocked by Cs+ ions and by the antiarrhythmic drug E-4031, a specific inhibitor of the HERG-codified channels. In cells adherent to bLN, IIR potentiation (85%) persisted for 90-120 min and was accompanied by a similar, but transient, increase in the leakage conductance (GL). Successively, the persistence of a high IIR conductance and the decrease of GL progressively bring VREST from -12 to ∼ -30 mV in about 120 min. On the other hand, in cells adherent to PL, exposure to sLN produced a similar but not persistent activation of IIR, without any increase in GL. this caused a rapid, transient hyperpolarisation of VREST. The effects of bLN and sLN were mimicked by antibodies raised against the integrin β1 subunit, suggesting a specific integrin-mediated mechanism. In fact, when bound to the culture dishes, these antibodies simultaneously activated the IIR and GL, whereas in soluble form they only activated IIR. Cells adherent to bLN emitted neurites, a process impaired by the block of IIR by E-4031 and Cs-. On the whole data suggest that the integrin-mediated activation of IIR plays a crucial role in the commitment to neuritogenesis of neuroblastoma cells, independently on the effects of this activation on VREST.
KW - Electrical signals
KW - Integrin receptors
KW - Inward rectifier K channels
KW - Neuritogenesis
KW - Neuroblastoma
KW - Soluble and bound laminin
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UR - http://www.scopus.com/inward/citedby.url?scp=0030480853&partnerID=8YFLogxK
M3 - Article
C2 - 9117354
AN - SCOPUS:0030480853
VL - 4
SP - 369
EP - 385
JO - Cell Adhesion and Communication
JF - Cell Adhesion and Communication
SN - 1061-5385
IS - 4-5
ER -