Cardiac‐specific Overexpression of the Human Short Clc‐3 Chloride Channel Isoform in Mice

Abstract

1. ClC-3 has been proposed as a molecular candidate responsible for volume-sensitive outwardly rectifying anion channels (VSOAC) in cardiac and smooth muscle cells. To further test this hypothesis, we produced a novel line of transgenic mice with cardiac-specific overexpression of the human short ClC-3 isoform (hsClC-3). 2. Northern and western blot analyses demonstrated that mRNA and protein levels of the short isoform (sClC-3) in the heart were significantly increased in hsClC-3-overexpressing (OE) mice compared with wild-type (WT) mice. Heart weight : bodyweight ratios for OE mice were significantly smaller compared with age-matched WT mice. 3. Electrocardiogram recordings indicated no difference at rest, whereas echocardiographic recordings revealed consistent reductions in left ventricular diastolic diameter, left ventricular posterior wall thickness at end of diastole and interventricular septum thickness in diastole in OE mice. 4. The VSOAC current densities in atrial cardiomyocytes were significantly increased by ClC-3 overexpression compared with WT cells. No differences in VSOAC current properties in OE and WT atrial myocytes were observed in terms of outward rectification, anion permeability (I(-) > Cl(-) > Asp(-)) and inhibition by 4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid and glibenclamide. The VSOAC in atrial myocytes from both groups were totally abolished by phorbol-12,13-dibutyrate (a protein kinase C activator) and by intracellular dialysis of an N-terminal anti-ClC-3 antibody. 5. Cardiac cell volume measurements revealed a significant acceleration of the rate of regulatory volume decrease (RVD) in OE myocytes compared with WT. 6. In conclusion, enhanced VSOAC currents and acceleration of the time-course of RVD in atrial myocytes of OE mice is strong evidence supporting an essential role of sClC-3 in native VSOAC function in mouse atrial myocytes.

Molecular Interaction and Functional Regulation of ClC-3 by Ca2+/Calmodulin-dependent Protein Kinase II (CaMKII) in Human Malignant Glioma

“…Membrane-For ClC-3 to play a role in cell migration (8,11,35), proliferation (9,17,36), and volume regulation (37,38), we hypothesize that it is at least partially expressed on the cell membrane. Using confocal imaging, we found that ClC-3 colocalizes with cortical actin at the cell membrane (Fig.…”

Developmental delays consistent with cochlear hypothyroidism contribute to failure to develop hearing in mice lacking Slc26a4/pendrin expression

“…Pendrin, which is an exchanger that transports anions such as Cl Ϫ , I Ϫ , and HCO 3 Ϫ , is involved in the secretion of I Ϫ across the apical membrane of thyroid follicular epithelial cells (24,50,51,53,56,66). In addition to pendrin, several other I Ϫ -permeable transporters may contribute to I Ϫ transport including the anion/proton exchangers, ClC-3 and ClC-5, and the anion channels Cftr and Slc26a7 (6,19,40,61,65). Expression levels of pendrin in the murine thyroid have been found to be ϳ50-fold less than in the kidney (61).…”

Regulatory Volume Increase and Regulatory Volume Decrease Responses in HL-1 Atrial Myocytes

“…HL-1 cells show RVD response following hypotonic challenge, similar to responses seen in other cardiac atrial cells [16]. Moreover, HL-1 cardiac cells show abundant RVI responses.…”

“…The RVD response in cardiac myocytes has been studied from the following models: embryonic chicken, neonatal rat, guinea pig, rabbit adult ventricular myocytes and mouse adult atrial myocytes [10,11,12,13,14,15,16]. Cultured chick embryo cardiac myocytes [17,18], ventricular rat myocytes [15], adult rabbit ventricular myocytes [19] and mouse atrial myocytes [16] can exhibit RVD. However, others reported the absence of spontaneous RVD in neonatal rat and guinea pig cardiac myocytes [10,13,20,21].…”