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. 2001 Jan 15;353(Pt 2):333–338. doi: 10.1042/0264-6021:3530333

Inhibition of prolyl 4-hydroxylase in vitro and in vivo by members of a novel series of phenanthrolinones.

T J Franklin 1, W P Morris 1, P N Edwards 1, M S Large 1, R Stephenson 1
PMCID: PMC1221576  PMID: 11139398

Abstract

Examples of a novel series of phenanthrolinones are shown to be potent competitive inhibitors of avian prolyl 4-hydroxylase, and of collagen hydroxylation, in embryonic chick tendon cells and human foreskin fibroblasts in vitro and in the oestradiol-stimulated rat uterus in vivo. Two compounds, Compound 1 (1,4-dihydrophenanthrolin-4-one-3-carboxylic acid) and Compound 5 [8-(N-butyl-N-ethylcarbamoyl)-1,4-dihydrophenathrolin-4-one-3-carboxylic acid], with comparable potencies in vivo, were chosen to investigate the effect of the inhibition of the hydroxylation of newly synthesized uterine collagen on the turnover of this protein in vivo. Inhibition of hydroxylation by more than 50% for approx. 8 h following single oral doses of the compounds was associated with significant losses of radiolabelled proline and 4-hydroxyproline from collagen during this period. Progressive hydroxylation of collagen over 48 h, as the inhibitory action of the compounds declined, was accompanied by a decreased loss of radiolabel from the uterine collagen. Earlier reports indicated that underhydroxylated collagen, accumulating within the endoplasmic reticulum in cells where prolyl 4-hydroxylase is inactivated, is slowly degraded, but is then rapidly hydroxylated and secreted when the activity of prolyl 4-hydroxylase is restored. Taken with the present results, this suggests that the potential use of inhibitors of prolyl 4-hydroxylase to control excessive collagen deposition in pathological fibrosis may be limited by the need to maintain continuous inhibition of collagen hydroxylation so as to facilitate intracellular degradation of the accumulated protein.

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Selected References

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  1. Berg R. A., Schwartz M. L., Crystal R. G. Regulation of the production of secretory proteins: intracellular degradation of newly synthesized "defective" collagen. Proc Natl Acad Sci U S A. 1980 Aug;77(8):4746–4750. doi: 10.1073/pnas.77.8.4746. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Cunliffe C. J., Franklin T. J., Gaskell R. M. Assay of prolyl 4-hydroxylase by the chromatographic determination of [14C]succinic acid on ion-exchange minicolumns. Biochem J. 1986 Dec 1;240(2):617–619. doi: 10.1042/bj2400617. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Franklin T. J., Hales N. J., Johnstone D., Morris W. B., Cunliffe C. J., Millest A. J., Hill G. B. Approaches to the design of anti-fibrotic drugs. Biochem Soc Trans. 1991 Nov;19(4):812–815. doi: 10.1042/bst0190812. [DOI] [PubMed] [Google Scholar]
  4. Franklin T. J., Hitchen M. Inhibition of collagen hydroxylation by 2,7,8-trihydroxyanthraquinone in embryonic-chick tendon cells. Biochem J. 1989 Jul 1;261(1):127–130. doi: 10.1042/bj2610127. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Franklin T. J. Therapeutic approaches to organ fibrosis. Int J Biochem Cell Biol. 1997 Jan;29(1):79–89. doi: 10.1016/s1357-2725(96)00121-5. [DOI] [PubMed] [Google Scholar]
  6. Hanauske-Abel H. M. Prolyl 4-hydroxylase, a target enzyme for drug development. Design of suppressive agents and the in vitro effects of inhibitors and proinhibitors. J Hepatol. 1991;13 (Suppl 3):S8–S16. doi: 10.1016/0168-8278(91)90003-t. [DOI] [PubMed] [Google Scholar]
  7. Jimenez S. A., Yankowski R. Role of molecular conformation on secretion of chick tendon procollagen. J Biol Chem. 1978 Mar 10;253(5):1420–1426. [PubMed] [Google Scholar]
  8. Kedersha N. L., Berg R. A. An improved method for the purification of vertebrate prolyl hydroxylase by affinity chromatography. Coll Relat Res. 1981 Jul;1(4):345–353. doi: 10.1016/s0174-173x(81)80011-8. [DOI] [PubMed] [Google Scholar]
  9. Klausner R. D., Sitia R. Protein degradation in the endoplasmic reticulum. Cell. 1990 Aug 24;62(4):611–614. doi: 10.1016/0092-8674(90)90104-m. [DOI] [PubMed] [Google Scholar]
  10. Kurisu K., Ohsaki Y., Nagata K., Inai T., Kukita T. Heterogeneous distribution of the precursor of type I and type III collagen and fibronectin in the rough endoplasmic reticulum of palatal mesenchymal cells of the mouse embryo cultured in ascorbate-depleted medium. Cell Tissue Res. 1992 Mar;267(3):429–435. doi: 10.1007/BF00319365. [DOI] [PubMed] [Google Scholar]
  11. Pacifici M., Iozzo R. V. Remodeling of the rough endoplasmic reticulum during stimulation of procollagen secretion by ascorbic acid in cultured chondrocytes. A biochemical and morphological study. J Biol Chem. 1988 Feb 15;263(5):2483–2492. [PubMed] [Google Scholar]
  12. Rosenbloom J., Harsch M., Jimenez S. Hydroxyproline content determines the denaturation temperature of chick tendon collagen. Arch Biochem Biophys. 1973 Oct;158(2):478–484. doi: 10.1016/0003-9861(73)90539-0. [DOI] [PubMed] [Google Scholar]
  13. Tschank G., Brocks D. G., Engelbart K., Mohr J., Baader E., Günzler V., Hanauske-Abel H. M. Inhibition of prolyl hydroxylation and procollagen processing in chick-embryo calvaria by a derivative of pyridine-2,4-dicarboxylate. Characterization of the diethyl ester as a proinhibitor. Biochem J. 1991 Apr 15;275(Pt 2):469–476. doi: 10.1042/bj2750469. [DOI] [PMC free article] [PubMed] [Google Scholar]

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