title: Inhibition of hyaluronan synthesis in Streptococcus equi FM100 by 4-methylumbelliferone.
abstract: As observed previously in cultured human skin fibroblasts, a decrease of hyaluronan production was also observed in group C Streptococcus equi FM100 cells treated with 4-methylumbelliferone (MU), although there was no effect on their growth. In this study, the inhibition mechanism of hyaluronan synthesis by MU was examined using Streptococcus equi FM100, as a model. When MU was added to a reaction mixture containing the two sugar nucleotide donors and a membrane-rich fraction as an enzyme source in a cell-free hyaluronan synthesis experiment, there was no change in the production of hyaluronan. On the contrary, when MU was added to the culture medium of FM100 cells, hyaluronan production in the isolated membranes was decreased in a dose-dependent manner. However, when the effect of MU on the expression level of hyaluronan synthase was examined, MU did not decrease either the mRNA level of the has operon containing the hyaluronan synthase gene or the protein level of hyaluronan synthase. Solubilization of the enzyme from membranes of MU-treated cells and addition of the exogenous phospholipid, cardiolipin, rescued hyaluronan synthase activity. In the mass spectrometric analysis of the membrane phospholipids from FM100 cells treated with MU, changes were observed in the distribution of only cardiolipin species but not of the other major phospholipid, PtdGro. These results suggest that MU treatment may cause a decrease in hyaluronan synthase activity by altering the lipid environment of membranes, especially the distribution of different cardiolipin species, surrounding hyaluronan synthase.
authors.affiliation: Departments of Biochemistry and Bacteriology, Hirosaki University School of Medicine, Hirosaki, Japan.
authors.forename: Ikuko
authors.initials: I
authors.lastname: Kakizaki
authors.forename: Keiichi
authors.initials: K
authors.lastname: Takagaki
authors.forename: Yasufumi
authors.initials: Y
authors.lastname: Endo
authors.forename: Daisuke
authors.initials: D
authors.lastname: Kudo
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Ikeya
authors.forename: Teruzo
authors.initials: T
authors.lastname: Miyoshi
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Baggenstoss
authors.forename: Valarie L
authors.initials: VL
authors.lastname: Tlapak-Simmons
authors.forename: Kshama
authors.initials: K
authors.lastname: Kumari
authors.forename: Akio
authors.initials: A
authors.lastname: Nakane
authors.forename: Paul H
authors.initials: PH
authors.lastname: Weigel
authors.forename: Masahiko
authors.initials: M
authors.lastname: Endo
mesh_terms: D002474:Cell-Free System; D014453:Glucuronosyltransferase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D016695:Glycosyltransferases; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D006923:Hymecromone / Q000494:pharmacology*; D008563:Membrane Lipids / Q000378:metabolism; D008565:Membrane Proteins; D010743:Phospholipids / Q000737:chemistry / Q000378:metabolism; D018502:Streptococcus equi / Q000187:drug effects* / Q000378:metabolism*; D014166:Transferases; D029867:Xenopus Proteins
chemical_list: D008563:Membrane Lipids; D008565:Membrane Proteins; D010743:Phospholipids; D029867:Xenopus Proteins; D006923:Hymecromone; D006820:Hyaluronic Acid; D014166:Transferases; D016695:Glycosyltransferases; D014453:Glucuronosyltransferase; C056944:HAS1 protein, Xenopus; D000076002:Hyaluronan Synthases