title: Chronic administration of calcitriol enhanced neuregulin-1/ErbB signaling in rat myocardium.
abstract: Although emerging evidence suggests that vitamin D has beneficial effects in the cardiovascular health, the underlying mechanisms are far from fully elucidated. Given the indispensable role of neuregulin-1 (NRG1)/ErbB signaling in the cardiovascular system, the present study investigated the influences of prolonged administration of calcitriol, the active form of vitamin D, on the NRG1/ErbB system. We examined the protein expression of NRG1, ErbB receptors (ErbB2 and ErbB4) and their phosphorylated forms in the myocardium of rats following 6-week administration of calcitriol (50 ng/kg/day or 100 ng/kg/day). We further assessed the myocardial vitamin D receptor (VDR) to confirm the effect of calcitriol treatment. Additionally, serum neuregulin-1 level was also analyzed. Generally, calcitriol enhanced myocardial VDR expression and NRG1/ErbB signaling. Calcitriol increased NRG1 protein level at the higher dose, while both doses promoted ErbB2 and phosphorylated ErbB2 expression. Although calcitriol has no significant influence on ErbB4 expression, phosphorylated ErbB4 receptors were enhanced at the higher dose. Furthermore, the serum neuregulin-1 concentration was increased at both doses. Overall, our data firstly showed that chronic calcitriol administration enhanced NRG1/ErbB signaling in the heart, indicating a novel mechanism underlying the cardiac effects of vitamin D.
authors.forename: Ruili
authors.initials: R
authors.lastname: Dang
authors.forename: Yujin
authors.initials: Y
authors.lastname: Guo
authors.forename: Yungui
authors.initials: Y
authors.lastname: Zhu
authors.forename: Ranyao
authors.initials: R
authors.lastname: Yang
authors.forename: Hualin
authors.initials: H
authors.lastname: Cai
authors.forename: Pei
authors.initials: P
authors.lastname: Jiang
mesh_terms: D000818:Animals; D002117:Calcitriol / Q000494:pharmacology*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D020890:Neuregulin-1 / Q000096:biosynthesis / Q000097:blood / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis / Q000187:drug effects*; D066247:Receptor, ErbB-4 / Q000096:biosynthesis / Q000187:drug effects*; D018167:Receptors, Calcitriol / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D002117:Calcitriol; D002120:Calcium Channel Agonists; D020890:Neuregulin-1; D018719:Erb-b2 Receptor Tyrosine Kinases; D066247:Receptor, ErbB-4; D018167:Receptors, Calcitriol; C490580:Nrg1 protein, rat; C483804:Erbb2 protein, rat; C587691:Erbb4 protein, rat