title: Influence of the extracellular matrix and integrins on volume-sensitive osmolyte anion channels in C2C12 myoblasts.
abstract: The purpose of this study was to determine whether extracellular matrix (ECM) composition through integrin receptors modulated the volume-sensitive osmolyte anion channels (VSOACs) in skeletal muscle-derived C2C12 cells. Cl(-) currents were recorded in whole cell voltage-clamped cells grown on laminin (LM), fibronectin (FN), or in the absence of a defined ECM (NM). Basal membrane currents recorded in isotonic media (300 mosmol/kg) were larger in cells grown on FN (3.8-fold at +100 mV) or LM (8.8-fold at +100 mV) when compared with NM. VSOAC currents activated by cell exposure to hypotonic solution were larger in cells grown on LM (1.72-fold at +100 mV) or FN (1.75-fold at +100 mV) compared with NM. Additionally, the kinetics of VSOAC activation was approximately 27% quicker on FN and LM. These currents were tamoxifen sensitive, displayed outward rectification, reversed at the equilibrium potential of Cl(-) and inactivated at potentials >+60 mV. Specific knockdown of beta(1)-integrin by short hairpin RNA interference strongly inhibited the VSOAC Cl(-) currents in cells plated on FN. In conclusion, ECM composition and integrins profoundly influence the biophysical properties and mechanisms of onset of VSOACs.
authors.affiliation: Dept. of Biochemistry, Univ. of Nevada School of Medicine, Reno, NV 89557, USA.
authors.forename: Iva
authors.initials: I
authors.lastname: Neveux
authors.forename: Jinger
authors.initials: J
authors.lastname: Doe
authors.forename: Normand
authors.initials: N
authors.lastname: Leblanc
authors.forename: Maria L
authors.initials: ML
authors.lastname: Valencik
mesh_terms: D000138:Acidosis / Q000097:blood / Q000139:chemically induced / Q000378:metabolism / Q000652:urine; D000818:Animals; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death; D018118:Chloride Channels / Q000378:metabolism*; D005109:Extracellular Matrix / Q000378:metabolism*; D005786:Gene Expression Regulation; D018698:Glutamic Acid; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D006801:Humans; D006851:Hydrochloric Acid / Q000494:pharmacology; D016023:Integrins / Q000378:metabolism*; D051379:Mice; D032446:Myoblasts / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D027982:Sodium-Bicarbonate Symporters / Q000235:genetics / Q000378:metabolism*
chemical_list: D018118:Chloride Channels; D016023:Integrins; C498902:Slc4a7 protein, rat; D027982:Sodium-Bicarbonate Symporters; D018698:Glutamic Acid; D053148:Caspase 3; D006851:Hydrochloric Acid