title: Thymosin beta4 regulates cardiac valve formation via endothelial-mesenchymal transformation in zebrafish embryos.
abstract: Thymosin beta4 (TB4) has multiple functions in cellular response in processes as diverse as embryonic organ development and the pathogeneses of disease, especially those associated with cardiac coronary vessels. However, the specific roles played by TB4 during heart valve development in vertebrates are largely unknown. Here, we identified a novel function of TB4 in endothelialmesenchymal transformation (EMT) in cardiac valve endocardial cushions in zebrafish. The expressions of thymosin family members in developing zebrafish embryos were determined by whole mount in situ hybridization. Of the thymosin family members only zTB4 was expressed in the developing heart region. Cardiac valve development at 48 h post fertilization was defected in zebrafish TB4 (zTB4) morpholino-injected embryos (morphants). In zTB4 morphants, abnormal linear heart tube development was observed. The expressions of bone morphogenetic protein (BMP) 4, notch1b, and hyaluronic acid synthase (HAS) 2 genes were also markedly reduced in atrio-ventricular canal (AVC). Endocardial cells in the AVC region were stained with anti-Zn5 antibody reactive against Dm-grasp (an EMT marker) to observe EMT in developing cardiac valves in zTB4 morphants. EMT marker expression in valve endothelial cells was confirmed after transfection with TB4 siRNA in the presence of transforming growth factor β (TGFβ) by RT-PCR and immunofluorescent assay. Zn5-positive endocardial AVC cells were not observed in zTB4 morphants, and knockdown of TB4 suppressed TGF-β-induced EMT in ovine valve endothelial cells. Taken together, our results demonstrate that TB4 plays a pivotal role in cardiac valve formation by increasing EMT.1.
authors.affiliation: Research Institute of Pharmaceutical Sciences, College of Pharmacy, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Sun-Hye
authors.initials: SH
authors.lastname: Shin
authors.forename: Sangkyu
authors.initials: S
authors.lastname: Lee
authors.forename: Jong-Sup
authors.initials: JS
authors.lastname: Bae
authors.forename: Jun-Goo
authors.initials: JG
authors.lastname: Jee
authors.affiliation: Department of Parasitology and Genetics, Kosin University College of Medicine, Busan 602-703, Korea.
authors.forename: Hee-Jae
authors.initials: HJ
authors.lastname: Cha
authors.affiliation: School of Life Sciences and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: You Mie
authors.initials: YM
authors.lastname: Lee
mesh_terms: D000818:Animals; D002417:Cattle; D002454:Cell Differentiation / Q000235:genetics; D002460:Cell Line; D004625:Embryo, Nonmammalian; D047108:Embryonic Development / Q000235:genetics; D004727:Endothelium / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D006351:Heart Valves / Q000196:embryology* / Q000473:pathology; D006801:Humans; D008648:Mesoderm / Q000502:physiology*; D016376:Oligonucleotides, Antisense / Q000235:genetics; D038081:Organogenesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D012756:Sheep; D013947:Thymosin / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism; D015027:Zebrafish; D000099201:Thymosin beta(4)
chemical_list: D016376:Oligonucleotides, Antisense; D034741:RNA, Small Interfering; D013947:Thymosin; D016212:Transforming Growth Factor beta; D000099201:Thymosin beta(4)
references.citation: Nature. 2003 Oct 9;425(6958):577-84
references.pmid: 14534577
references.citation: Cardiovasc Res. 2011 Jul 15;91(2):279-88
references.pmid: 21602174
references.citation: Biochem Biophys Res Commun. 2008 Sep 26;374(3):512-6
references.pmid: 18647596
references.citation: Expert Opin Biol Ther. 2012 Jan;12(1):37-51
references.pmid: 22074294
references.citation: Development. 2005 Dec;132(23):5199-209
references.pmid: 16251212
references.citation: Development. 2005 Sep;132(18):4193-204
references.pmid: 16107477
references.citation: FASEB J. 1997 May;11(6):474-81
references.pmid: 9194528
references.citation: Development. 2002 Oct;129(19):4443-55
references.pmid: 12223403
references.citation: Int J Biochem Cell Biol. 2001 Mar;33(3):205-20
references.pmid: 11311852
references.citation: Nature. 2004 Nov 25;432(7016):466-72
references.pmid: 15565145
references.citation: Exp Eye Res. 2002 Feb;74(2):293-9
references.pmid: 11950239
references.citation: Biochim Biophys Acta. 1996 May 2;1306(2-3):187-93
references.pmid: 8634336
references.citation: J Invest Dermatol. 1999 Sep;113(3):364-8
references.pmid: 10469335
references.citation: Cancer Invest. 2013 Feb;31(2):103-10
references.pmid: 23320791
references.citation: Am J Pathol. 2001 Oct;159(4):1335-43
references.pmid: 11583961
references.citation: J Biol Chem. 2003 Jan 17;278(3):1686-92
references.pmid: 12427739
references.citation: PLoS One. 2013 Apr 17;8(4):e61960
references.pmid: 23613983
references.citation: Am J Anat. 1977 Jan;148(1):85-119
references.pmid: 842477
references.citation: Development. 2006 Mar;133(6):1125-32
references.pmid: 16481353
references.citation: Dev Biol. 2010 Nov 15;347(2):325-36
references.pmid: 20816797
references.citation: Ann N Y Acad Sci. 2012 Oct;1270:112-9
references.pmid: 23050826
references.citation: Pathol Oncol Res. 2013 Apr;19(2):237-45
references.pmid: 23055022
references.citation: Dev Dyn. 2003 Sep;228(1):30-40
references.pmid: 12950077
references.citation: FEBS Lett. 2010 Jan 4;584(1):141-6
references.pmid: 19914243
references.citation: Circ Res. 2004 Sep 3;95(5):459-70
references.pmid: 15345668
references.citation: Dev Biol. 1999 Oct 1;214(1):23-37
references.pmid: 10491254
references.citation: Dev Biol. 2009 Jun 15;330(2):213-20
references.pmid: 19371733
references.citation: Nature. 2011 Jun 08;474(7353):640-4
references.pmid: 21654746
references.citation: J Heart Valve Dis. 2002 Sep;11(5):726-35
references.pmid: 12358412
references.citation: Curr Pharm Des. 2012;18(6):799-806
references.pmid: 22236126
references.citation: Dev Dyn. 2006 Jan;235(1):29-37
references.pmid: 16170785
references.citation: Nature. 2007 Jan 11;445(7124):177-82
references.pmid: 17108969
references.citation: Exp Cell Res. 2004 Feb 1;293(1):175-83
references.pmid: 14729067
references.citation: Cold Spring Harb Symp Quant Biol. 2002;67:49-56
references.pmid: 12858523
references.citation: J Mol Cell Cardiol. 2009 May;46(5):728-38
references.pmid: 19358334