title: Heat shock protein 70 of Naegleria fowleri is important factor for proliferation and in vitro cytotoxicity.
abstract: To evaluate the role of heat shock 70 protein (HSP70) in free-living amoeba, a constitutive and inducible heat shock 70 gene of pathogenic Naegleria fowleri has previously been cloned, characterized, and named as Nf-cHSP70. The Nf-cHSP70 is localized in the cytoplasm, pseudopodia, and phagocytic food-cups. To investigate the role of Nf-cHSP70 in the pathogenicity of N. fowleri, the synthesis of N. fowleri HSP70 was first inhibited with benzylidene lactam compound (KNK437), and Nf-cHSP70 gene was knock-downed with antisense oligomers, which were designed with a start region-specific antisense oligonucleotides (24 oligomers) and modified with phosphorothioate. KNK437 inhibited the induction of N. fowleri HSP70 in a dose-dependent manner. In addition, 300 muM KNK437 reduced the proliferation of N. fowleri to 79.4% of untreated control (100%). Nf-cHSP70 knock-downed N. fowleri with antisense oligomers showed 68.5% reduction of proliferation in comparison with untreated control (100%). The cytotoxicity of N. fowleri against CHO target cells was reduced to 42.1% by KNK437 and 68.6% by antisense oligomers. These results suggest that the cloned Nf-cHSP70 plays an important role in the proliferation and cytotoxicity of pathogenic N. fowleri.
authors.affiliation: Department of Environmental Medical Biology, Yonsei University College of Medicine, Seoul, 121-752, South Korea.
authors.forename: Kyoung-Ju
authors.initials: KJ
authors.lastname: Song
authors.forename: Kyung-Hui
authors.initials: KH
authors.lastname: Song
authors.forename: Jong-Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Hae-Jin
authors.initials: HJ
authors.lastname: Sohn
authors.forename: Yang-Jin
authors.initials: YJ
authors.lastname: Lee
authors.forename: Chang-Eun
authors.initials: CE
authors.lastname: Park
authors.forename: Ho-Joon
authors.initials: HJ
authors.lastname: Shin
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds / Q000494:pharmacology; D016466:CHO Cells / Q000469:parasitology; D006224:Cricetinae; D003412:Cricetulus; D017353:Gene Deletion; D018840:HSP70 Heat-Shock Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D016848:Naegleria fowleri / Q000254:growth & development* / Q000472:pathogenicity* / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D011760:Pyrrolidinones / Q000494:pharmacology; D053058:Trophozoites / Q000254:growth & development
chemical_list: D001559:Benzhydryl Compounds; D018840:HSP70 Heat-Shock Proteins; C410027:KNK 437; D015800:Protozoan Proteins; D011760:Pyrrolidinones