title: Common pathways for receptor-mediated ingestion of Escherichia coli and LDL cholesterol by Entamoeba histolytica regulated in part by transmembrane kinase 39.
abstract: The single-celled parasite, Entamoeba histolytica, is an enteric pathogen that ingests bacteria and host cells. Inhibition of phagocytosis renders the parasite avirulent. The ligand/receptor interactions that allow E. histolytica to phagocytose are not well understood. We hypothesised that E. histolytica trophozoites might accomplish ingestion through the utilisation of a scavenger receptor for cholesterol. Here we show that acetylated low density lipoprotein cholesterol was phagocytosed by amoebae via receptor mediated mechanisms. Acetylated low density lipoprotein cholesterol competitively inhibited by 31 ± 1.3% (P < 0.005) the ingestion of Escherichia coli, but not erythrocytes and Jurkat T lymphocytes, suggesting a partially redundant phagocytic pathway for E. coli and cholesterol. Inducible expression ofa signalling-dead dominant-negative version of E. histolytica transmembrane kinase 39 inhibited ingestion of E. coli by 55 ± 3% (P < 0.005) but not LDL particles. We concluded that ingestion of E. coli was regulated by TMK39 and partially shared the acetylated low density lipoprotein cholesterol uptake pathway.
authors.affiliation: Department of Microbiology, Immunology and Cancer Biology, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA.
authors.forename: Nathaniel C V
authors.initials: NC
authors.lastname: Christy
authors.forename: Sarah N
authors.initials: SN
authors.lastname: Buss
authors.forename: William A
authors.initials: WA
authors.lastname: Petri
mesh_terms: D008078:Cholesterol, LDL / Q000378:metabolism*; D004748:Entamoeba histolytica / Q000201:enzymology* / Q000378:metabolism / Q000382:microbiology / Q000502:physiology*; D004912:Erythrocytes / Q000378:metabolism / Q000382:microbiology; D004926:Escherichia coli / Q000302:isolation & purification*; D006801:Humans; D019169:Jurkat Cells / Q000378:metabolism / Q000382:microbiology; D010587:Phagocytosis; D010770:Phosphotransferases / Q000378:metabolism*; D021381:Protein Transport
chemical_list: D008078:Cholesterol, LDL; D010770:Phosphotransferases