title: Infection by Mycoplasma hyorhinis strongly enhances uptake of antisense oligonucleotides: a reassessment of receptor-mediated endocytosis in the HepG2 cell line.
abstract: This paper shows that the approximately 66 kDa band, previously isolated from the HepG2 cell line as an oligonucleotide (ON) plasma membrane 'receptor', is induced by Mycoplasma infection. Moreover, this band has been identified as the invariant membrane protein of Mycoplasma hyorhinis, p70, based on ribosomal DNA sequencing combined with ON ligand blotting after p70 immunoprecipitation by a monoclonal antibody. Whereas antibiotic treatment of infected HepG2 cells strongly decreased ON capture, as measured by a biochemical assay, conversely, deliberate infection of HeLa cells with M.hyorhinis dramatically promoted ON uptake but did not affect receptor-mediated endocytosis of transferrin. This was confirmed by confocal microscopy of infected HepG2 cells, which also showed an indistinguishable labelling pattern after exposure of living cells to fluorescent ON and after p70 immunolabelling in permeabilised fixed cells. We propose that ON binds to p70 on M.hyorhinis attached at the cell surface, after which the complex is internalised by 'piggy-back' endocytosis.
authors.affiliation: Cell Biology Unit, Christian de Duve Institute of Cellular Pathology and Université catholique de Louvain, UCL 7541, 75 avenue Hippocrate, B-1200 Brussels, Belgium. diesbach@cell.ucl.ac.be
authors.forename: Philippe
authors.initials: P
authors.lastname: de Diesbach
authors.forename: Francisca
authors.initials: F
authors.lastname: N'Kuli
authors.forename: Michel
authors.initials: M
authors.lastname: Delmée
authors.forename: Pierre J
authors.initials: PJ
authors.lastname: Courtoy
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D004705:Endocytosis; D006367:HeLa Cells; D006801:Humans; D009174:Mycoplasma; D016376:Oligonucleotides, Antisense / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D000900:Anti-Bacterial Agents; D001425:Bacterial Outer Membrane Proteins; D016376:Oligonucleotides, Antisense; D011956:Receptors, Cell Surface