title: Gallate, the component of HIF-inducing catechins, inhibits HIF prolyl hydroxylase.
abstract: Catechins have recently been reported to increase the cellular content of the hypoxia-inducible factor (HIF)-1alpha within mammalian cells. These catechins have a gallate moiety as a common structure. We now report that n-propyl gallate (nPG) also increases the HIF-1alpha protein in the rat heart-derived H9c2 cells. The increase was dose-dependent and reached a maximum at 2-4h after the addition of nPG to the cells. nPG did not change the HIF-1alpha mRNA level, showing that the increase is a posttranscriptional event. Although nPG did not inhibit the HIF prolyl hydroxylase, gallate, the hydrolysis product of nPG, inhibited the enzyme completely at submillimolar concentrations. Model building studies on the human HIF prolyl hydroxylase 2 showed that the two phenolate oxygen atoms of gallate form a chelate with the active site Fe(2+), while the carboxyl group of gallate forms a strong ionic/hydrogen bonding interaction with Arg383, explaining why nPG, which has an esterified carboxyl group, is unable to inhibit the hydroxylase. Together with the observation that gallate was detected in the H9c2 cells treated with nPG, these results suggest that nPG incorporated into the cells is hydrolyzed and the released gallate inhibits the HIF prolyl hydroxylase, thereby reducing the HIF degradation rate and increasing the HIF-1alpha content.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, Osaka Medical College, Daigakumachi, Takatsuki 569-8686, Japan.
authors.forename: Fuyo
authors.initials: F
authors.lastname: Tsukiyama
authors.forename: Yumi
authors.initials: Y
authors.lastname: Nakai
authors.forename: Masataka
authors.initials: M
authors.lastname: Yoshida
authors.forename: Takahiro
authors.initials: T
authors.lastname: Tokuhara
authors.forename: Kiichi
authors.initials: K
authors.lastname: Hirota
authors.forename: Akiko
authors.initials: A
authors.lastname: Sakai
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Hayashi
authors.forename: Takahiro
authors.initials: T
authors.lastname: Katsumata
mesh_terms: D000818:Animals; D002396:Catechols / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D003198:Computer Simulation; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000737:chemistry* / Q000378:metabolism*; D008954:Models, Biological; D008956:Models, Chemical; D008958:Models, Molecular; D032342:Muscle Cells / Q000187:drug effects / Q000378:metabolism*; D011393:Procollagen-Proline Dioxygenase / Q000037:antagonists & inhibitors*; D011435:Propyl Gallate / Q000008:administration & dosage* / Q000737:chemistry*; D011485:Protein Binding; D011487:Protein Conformation; D051381:Rats
chemical_list: D002396:Catechols; D004791:Enzyme Inhibitors; C497443:Hif1a protein, mouse; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D011435:Propyl Gallate; D011393:Procollagen-Proline Dioxygenase; C034221:catechol