title: Role of mutation and pharmacologic block of human KCNH2 in vasculogenesis and fetal mortality: partial rescue by transforming growth factor-β.
abstract: BACKGROUND
  N629D KCNH2 is a human missense long-QT2 mutation. Previously, we reported that the N629D/N629D mutation embryos disrupted cardiac looping, right ventricle development, and ablated IKr activity at E9.5. The present study evaluates the role of KCNH2 in vasculogenesis.
  
  
  RESULTS
  N629D/N629D yolk sac vessels and aorta consist of sinusoids without normal arborization. Isolated E9.5 +/+ first branchial arches showed normal outgrowth of mouse ERG-positive/α-smooth muscle actin coimmunolocalized cells; however, outgrowth was grossly reduced in N629D/N629D. N629D/N629D aortas showed fewer α-smooth muscle actin positive cells that were not coimmunolocalized with mouse ERG cells. Transforming growth factor-β treatment of isolated N629D/N629D embryoid bodies partially rescued this phenotype. Cultured N629D/N629D embryos recapitulate the same cardiovascular phenotypes as seen in vivo. Transforming growth factor-β treatment significantly rescued these embryonic phenotypes. Both in vivo and in vitro, dofetilide treatment, over a narrow window of time, entirely recapitulated the N629D/N629D fetal phenotypes. Exogenous transforming growth factor-β treatment also rescued the dofetilide-induced phenotype toward normal.
  
  
  CONCLUSIONS
  Loss of function of KCNH2 mutations results in defects in cardiogenesis and vasculogenesis. Because many medications inadvertently block the KCNH2 potassium current, these novel findings seem to have clinical relevance.
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Guoqi
authors: G
authors: Teng
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Xiang
authors: X
authors: Zhao
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: James P
authors: JP
authors: Lees-Miller
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Darrell
authors: D
authors: Belke
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Chunhua
authors: C
authors: Shi
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Yongxiang
authors: Y
authors: Chen
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Edward R
authors: ER
authors: O'Brien
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Paul W
authors: PW
authors: Fedak
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: Nathan
authors: N
authors: Bracey
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada.
authors: James C
authors: JC
authors: Cross
authors: From the Libin Cardiovascular Institute, Faculty of Medicine (G.T., J.P.L.-M., D.B., C.S., Y.C., E.R.O'B., P.W.F., N.B., H.J.D.) and Department of Comparative Biology and Experimental Medicine and Faculty of Veterinary Medicine (X.Z., J.C.C.), University of Calgary, Calgary, Alberta, Canada. hduff@ucalgary.ca.
authors: Henry J
authors: HJ
authors: Duff
mesh_terms: D000014:Abnormalities, Drug-Induced / Q000196:embryology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D000818:Animals; D002478:Cells, Cultured; D000072237:ERG1 Potassium Channel; D046149:Embryo Culture Techniques; D053595:Embryonic Stem Cells / Q000187:drug effects* / Q000378:metabolism; D051638:Ether-A-Go-Go Potassium Channels / Q000037:antagonists & inhibitors* / Q000235:genetics* / Q000378:metabolism; D005313:Fetal Death; D018507:Gene Expression Regulation, Developmental; D005838:Genotype; D006330:Heart Defects, Congenital / Q000139:chemically induced / Q000196:embryology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D006801:Humans; D057507:Mice, 129 Strain; D008822:Mice, Transgenic; D009024:Morphogenesis / Q000187:drug effects; D020125:Mutation, Missense; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D010627:Phenethylamines / Q000633:toxicity*; D010641:Phenotype; D026902:Potassium Channel Blockers / Q000633:toxicity*; D015398:Signal Transduction; D013449:Sulfonamides / Q000633:toxicity*; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D054079:Vascular Malformations / Q000139:chemically induced / Q000196:embryology / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C000606915:Kcnh2 protein, mouse; D010627:Phenethylamines; D026902:Potassium Channel Blockers; D013449:Sulfonamides; D016212:Transforming Growth Factor beta; C063533:dofetilide
keywords: aorta; embryonic development; gene targeting; mice; organogenesis; potassium channels; transforming growth factor beta