1 Danish Biomembrane Research Centre, Faculty of Health Sciences, Aarhus University, Aarhus University2 Interdisciplinary Nanoscience Center, Faculty of Science, Aarhus University, Aarhus University3 Department of Physiology and Biophysics, Faculty of Health Sciences, Aarhus University, Aarhus University4 Department of Molecular Biology, Faculty of Science, Aarhus University, Aarhus University5 Department of Biomedicine - Forskning og uddannelse, Vest, Department of Biomedicine, Health, Aarhus University6 Department of Molecular Biology and Genetics - Gene Expression and Gene Medicine, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University7 Institute of Neuroscience and Physiology, University of Gothenburg, Sweden8 Department of Biomedicine - Forskning og uddannelse, Vest, Department of Biomedicine, Health, Aarhus University9 Department of Molecular Biology and Genetics - Gene Expression and Gene Medicine, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
We have recently characterized a cGMP-dependent Ca2+-activated Cl- current (ICl,cGMP) with unique characteristics in smooth muscle cells (SMCs) and suggested that this could be important for vasomotion in mesenteric arteries. We hypothesized that a bestrophin could be responsible for ICl,cGMP based on similarities in the membrane currents and on the distribution pattern of ICl,cGMP and bestrophin-3 protein expression in different SMCs. Bestrophin-3 was downregulated with small interference (siRNA) in rat mesenteric small arteries in vivo. Non-related siRNA and mutated bestrophin-3 siRNA were used as the controls. Downregulation induced by specific siRNA was evident by reduced expression of bestrophin-3 mRNA and protein (to 24+/-17 % and to 58+/-9 % of the control, n=3) without an effect on other bestrophin isoforms. SMCs downregulated for bestrophin-3 demonstrated a significant reduction of ICl,cGMP (by 98+/-0.2%, n=7 at -60 mV), while the “classical” Ca2+-activated Cl- current was unaffected. Surprisingly, arteries with reduced bestrophin-3 were more sensitive to noradrenaline than control vessels. The downregulation of bestrophin-3 significantly reduced the amplitude of arterial vasomotion (by 75+/-10 % n=6) without significant effect on frequency. We provide evidence that bestrophin-3 is essential for ICl,cGMP and is important for generation of vasomotion in rat mesenteric small arteries. This work was supported by the Danish Research Council, the Danish Heart Foundation. The Water and Salt Research Center at the University of Aarhus is established and supported by the Danish National Research Foundation.
Main Research Area:
25th Conference of the European Society for Microcirculation, 2008