title: Loss of epidermal growth factor receptor in vascular smooth muscle cells and cardiomyocytes causes arterial hypotension and cardiac hypertrophy.
abstract: The epidermal growth factor receptor (EGFR), a receptor tyrosine kinase, contributes to parainflammatory dysregulation, possibly causing cardiovascular dysfunction and remodeling. The physiological role of cardiovascular EGFR is not completely understood. To investigate the physiological importance of EGFR in vascular smooth muscle cells and cardiomyocytes, we generated a mouse model with targeted deletion of the EGFR using the SM22 (smooth muscle-specific protein 22) promoter. While the reproduction of knockout animals was not impaired, life span was significantly reduced. Systolic blood pressure was not different between the 2 genotypes-neither in tail cuff nor in intravascular measurements-whereas total peripheral vascular resistance, diastolic blood pressure, and mean blood pressure were reduced. Loss of vascular smooth muscle cell-EGFR results in a dilated vascular phenotype with minor signs of fibrosis and inflammation. Echocardiography, necropsy, and histology revealed a dramatic eccentric cardiac hypertrophy in knockout mice (2.5-fold increase in heart weight), with increased stroke volume and cardiac output as well as left ventricular wall thickness and lumen. Cardiac hypertrophy is accompanied by an increase in cardiomyocyte volume, a strong tendency to cardiac fibrosis and inflammation, as well as enhanced NADPH-oxidase 4 and hypertrophy marker expression. Thus, in cardiomyocytes, EGFR prevents excessive hypertrophic growth through its impact on reactive oxygen species balance, whereas in vascular smooth muscle cells EGFR contributes to the appropriate vascular wall architecture and vessel reactivity, thereby supporting a physiological vascular tone.
authors.affiliation: Julius-Bernstein-Institute of Physiology, Medical Faculty, University of Halle-Wittenberg, Halle, Germany. barbara.schreier@medizin.uni-halle.de
authors.forename: Barbara
authors.initials: B
authors.lastname: Schreier
authors.forename: Sindy
authors.initials: S
authors.lastname: Rabe
authors.forename: Bettina
authors.initials: B
authors.lastname: Schneider
authors.forename: Maria
authors.initials: M
authors.lastname: Bretschneider
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rupp
authors.forename: Stefanie
authors.initials: S
authors.lastname: Ruhs
authors.forename: Joachim
authors.initials: J
authors.lastname: Neumann
authors.forename: Uwe
authors.initials: U
authors.lastname: Rueckschloss
authors.forename: Maria
authors.initials: M
authors.lastname: Sibilia
authors.forename: Michael
authors.initials: M
authors.lastname: Gotthardt
authors.forename: Claudia
authors.initials: C
authors.lastname: Grossmann
authors.forename: Michael
authors.initials: M
authors.lastname: Gekle
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002302:Cardiac Output / Q000502:physiology; D006332:Cardiomegaly / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000378:metabolism / Q000503:physiopathology; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism*; D007022:Hypotension / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D051379:Mice; D018345:Mice, Knockout; D009131:Muscle, Smooth, Vascular / Q000378:metabolism* / Q000503:physiopathology; D032383:Myocytes, Cardiac / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D066246:ErbB Receptors