title: Tumor necrosis factor-alpha converting enzyme in the human placenta throughout gestation.
abstract: Ectodomain shedding of epidermal growth factor receptor ligands such as transforming growth factor- alpha (TGF-alpha), heparin-binding epidermal growth factor-like growth factor (HBEGF), and amphiregulin (AREG) is considered to be important during implantation. Tumor necrosis factor-alpha converting enzyme (TACE) has been suggested as the major sheddase for these molecules. The objectives of this study are (1) to characterize the expression of TACE in the human placenta throughout gestation; (2) to determine the association between the expression of TACE with TGF-alpha, HBEGF, and AREG; (3) to ascertain whether TACE mediates TGF-alpha, HBEGF, and AREG shedding; and (4) to examine the effect of hypoxia on the expression of TACE. By analyzing a total of 55 villous samples representing different gestational ages, the authors found that TACE was continuously expressed in the placentas throughout gestation and that the levels of TACE were positively correlated with the levels of TGF-alpha, HBEGF, and AREG. Preadministration of a TACE inhibitor in villous explant cultures or transfection of cytotrophoblastic cells with TACE-specific small interference RNA decreased the shedding of HBEGF and AREG. Moreover, hypoxia (2% O(2)) caused an increase in the levels of TACE mRNA and protein in villous explants and primary cytotrophoblastic cells in vitro. These results indicate that oxygen regulates the expression of TACE and that TACE may be important for placental development during human pregnancy.
authors.affiliation: Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, Taipei, Taiwan.
authors.forename: Tai-Ho
authors.initials: TH
authors.lastname: Hung
authors.forename: Szu-Fu
authors.initials: SF
authors.lastname: Chen
authors.forename: Ching-Chang
authors.initials: CC
authors.lastname: Hsieh
authors.forename: Jenn-Jeih
authors.initials: JJ
authors.lastname: Hsu
authors.forename: Meng-Jen
authors.initials: MJ
authors.lastname: Li
authors.forename: Yi-Lin
authors.initials: YL
authors.lastname: Yeh
authors.forename: T'sang-T'ang
authors.initials: TT
authors.lastname: Hsieh
mesh_terms: D051722:ADAM Proteins / Q000096:biosynthesis*; D000072198:ADAM17 Protein; D066258:Amphiregulin; D066255:EGF Family of Proteins; D005260:Female; D006023:Glycoproteins / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D010920:Placenta / Q000201:enzymology* / Q000378:metabolism; D011247:Pregnancy / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D014409:Tumor Necrosis Factor-alpha; D051722:ADAM Proteins; D000072198:ADAM17 Protein; C000606462:ADAM17 protein, human