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Molecular and Biochemical Properties of a Cysteine Protease of Acanthamoeba castellanii
Yeonchul Hong,Jung-Mi Kang,So-Young Joo,Su-Min Song,H??ng Giang Le,Th? Lam Thai,Jinyoung Lee,Youn-Kyoung Goo,Dong-Il Chung,Woon-Mok Sohn,Byoung-Kuk Na 대한기생충학열대의학회 2018 The Korean Journal of Parasitology Vol.56 No.5
Moon, Eun-Kyung,Hong, Yeonchul,Chung, Dong-Il,Goo, Youn-Kyoung,Kong, Hyun-Hee Masson Pub. USA 2015 Cornea Vol.34 No.12
PURPOSE:: The aim of this study was to improve the cytopathic effect (CPE) of antiamebic agents by combining with cellulose synthesis inhibitor as an encystation inhibitor. METHODS:: Cellulose synthesis inhibitors, 2,6-dichlorobenzonitrile (DCB) and isoxaben were used to block encystation of Acanthamoeba during cultivation. Cultured human corneal epithelial (HCE) cells and Acanthamoeba were treated with polyhexamethylene biguanide (PHMB) combined with cellulose synthesis inhibitors to evaluate the CPE as an antiamebic agent. RESULTS:: 0.02% PHMB showed a 51.9% CPE on HCE cells within 30 minutes but exhibited significant toxic effects on Acanthamoeba. At a level of 0.00125%, PHMB had no significant CPEs on HCE cells, whereas 100 μM DCB and 10 μM isoxaben significantly inhibited the formation of the inner cyst wall of Acanthamoeba during encystation, and Acanthamoeba trophozoites failed to convert into mature cysts. Although a low concentration (0.00125%) of PHMB was used, the novel combinations with 100 μM DCB or 10 μM isoxaben had 23.4% or 18.7% additional amebicidal effects on Acanthamoeba. However, 100 μM DCB and 10 μM isoxaben had no CPEs on HCE cells. CONCLUSIONS:: The combination of cellulose synthesis inhibitors with low concentrations of PHMB reduced the CPE on HCE cells and improved the amebicidal effect on Acanthamoeba by inhibition of encystation.
Autophagy Inhibitors as a Potential Antiamoebic Treatment for <i>Acanthamoeba</i> Keratitis
Moon, Eun-Kyung,Kim, So-Hee,Hong, Yeonchul,Chung, Dong-Il,Goo, Youn-Kyoung,Kong, Hyun-Hee American Society for Microbiology 2015 Antimicrobial agents and chemotherapy Vol.59 No.7
<P>Acanthamoeba cysts are resistant to extreme physical and chemical conditions. Autophagy is an essential pathway for encystation of Acanthamoeba cells. To evaluate the possibility of an autophagic Acanthamoeba encystation mechanism, we evaluated autophagy inhibitors, such as 3-methyladenine (3MA), LY294002, wortmannin, bafilomycin A, and chloroquine. Among these autophagy inhibitors, the use of 3MA and chloroquine showed a significant reduction in the encystation ratio in Acanthamoeba cells. Wortmannin also inhibited the formation of mature cysts, while LY294002 and bafilomycin A did not affect the encystation of Acanthamoeba cells. Transmission electron microscopy revealed that 3MA and wortmannin inhibited autophagy formation and that chloroquine interfered with the formation of autolysosomes. Inhibition of autophagy or autolysosome formation resulted in a significant block in the encystation in Acanthamoeba cells. Clinical treatment with 0.02% polyhexamethylene biguanide (PHMB) showed high cytopathic effects on Acanthamoeba trophozoites and cysts; however, it also revealed high cytopathic effects on human corneal epithelial cells. In this study, we investigated effects of the combination of a low (0.00125%) concentration of PHMB with each of the autophagy inhibitors 3MA, wortmannin, and chloroquine on Acanthamoeba and human corneal epithelial cells. These new combination treatments showed low cytopathic effects on human corneal cells and high cytopathic effects on Acanthamoeba cells. Taken together, these results provide fundamental information for optimizing the treatment of Acanthamoeba keratitis.</P>
Moon, Eun-Kyung,Chung, Dong-Il,Hong, Yeonchul,Kong, Hyun-Hee Elsevier 2011 Experimental parasitology Vol.127 No.4
<P><B>Graphical abstract</B></P><P><ce:figure id='f0015'></ce:figure></P><P><B>Research highlights</B></P><P>► Encystation efficiency of <I>Acanthamoeba</I> was attenuated by long term cultivation in vitro. ► A general functional classification of 2706 cyst ESTs and 2659 trophozoite ESTs were obtained by a BLASTX similarity search against the <B>KOG</B> database. ► The gene profile data of encysting <I>A. castellanii</I> were stored on the ‘<I>Acanthamoeba</I> ESTs database’ (http://knupara.knu.ac.kr). ► Cyst specific ESTs shows higher percentage in <B>G</B>, <B>H</B>, <B>I</B>, <B>D</B>, <B>T</B> and <B>O</B> article.</P> <P><B>Abstract</B></P><P>The life cycle of <I>Acanthamoeba</I> consists of two stages, trophozoite and cyst. The cyst form is resistant to almost all antibiotics. By long term cultivation, <I>Acanthamoeba</I> severely attenuated the encysting ability. To determine the changing of gene expression by the long term cultivation, especially focusing an encystation mediating factors, this study compared the ESTs of the fresh strain and the old strain, and trophozoite. Comparison of the KOG (euKaryotic Orthologous Groups) analysis relative to trophozoite revealed higher percentages of cyst ESTs related to <B>G</B> (Carbohydrate transport and metabolism), <B>H</B> (Coenzyme transport and metabolism), <B>I</B> (Lipid transport and metabolism), <B>D</B> (Cell cycle control, cell division, chromosome partitioning), <B>T</B> (signal transduction mechanisms), and <B>O</B> (Posttranslational modification, protein turnover, chaperones). In addition to this result, KOG analysis of fresh strain relative to old strain showed higher percentage of cyst ESTs related to metabolism category and T (signal transduction mechanisms) article. ESTs of the fresh strain revealed more various gene profiles compared to the old strain including encystation mediating factors like autophagy related proteins (Z article) and signal transduction proteins (T article). Twenty seven kinds of protein kinase C (PKC) like genes were detected in cyst or trophozoite ESTs and twenty one of them were highly expressed during encystation. The information of the expressed genes during encystation in only the fresh strain will provide new clues to understanding the encystation mechanism of encysting protozoa including <I>Acanthamoeba</I>.</P>