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Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii
Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully underst...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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Frontiers Media S.A.
2021
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835678/ https://www.ncbi.nlm.nih.gov/pubmed/33510719 http://dx.doi.org/10.3389/fmicb.2020.595080 |
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author | Wang, Ningning Sun, Hongyu Liu, Di Jiang, Xiaoming Zheng, Meiyu Zhu, Wenhe Liu, Quan Zheng, Wenyu Feng, Xianmin |
author_facet | Wang, Ningning Sun, Hongyu Liu, Di Jiang, Xiaoming Zheng, Meiyu Zhu, Wenhe Liu, Quan Zheng, Wenyu Feng, Xianmin |
author_sort | Wang, Ningning |
collection | PubMed |
description | Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully understood. This study aimed to determine the biological functions of heat shock protein (HSP)-20 of A. castellanii (Ac-HSP20) involved in the maintenance of life cycle and the infectivity of A. castellanii. Immunoscreening A. castellanii cDNA library with A. castellanii infected rabbit sera identified three positive clones, one of them was a putative heat shock protein (Ac-HSP20). The recombinant 23 kDa Ac-HSP20 protein (rAc-HSP20) was successfully expressed in Escherichia coli BL21 (DE3) and purified using metal affinity chromatography. The rabbits immunized with rAc-HSP20 produced high titer antibody (1:25,600). Immunolocalization with the antibody identified the expression of native Ac-HSP20 on the surface of both A. castellanii trophozoites and cysts. Further, Western blot with antibody identified that the expression of native Ac-HSP20 was 7.5 times higher in cysts than in trophozoites. Blocking Ac-HSP20 on the membrane of trophozoites with specific antibody or silencing Ac-hsp20 gene transcription by siRNA inhibited their transformation into cysts at the early stage but returned to normal at the late stage by stimulating the transcription of Ac-hsp20. Incubation of trophozoites with anti-Ac-HSP20 IgG increased macrophage-involved phagocytosis to the protozoa and inhibited trophozoite infectivity on the cornea of rabbits compared with that without antibody. Our study provides that Ac-HSP20 is a surface antigen involved in the encystation and infectivity of A. castellanii and thus an important target for vaccine and drug development. |
format | Online Article Text |
id | pubmed-7835678 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Frontiers Media S.A. |
record_format | MEDLINE/PubMed |
spelling | pubmed-78356782021-01-27 Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii Wang, Ningning Sun, Hongyu Liu, Di Jiang, Xiaoming Zheng, Meiyu Zhu, Wenhe Liu, Quan Zheng, Wenyu Feng, Xianmin Front Microbiol Microbiology Acanthamoeba castellanii is a pathogenic and opportunistic free-living amoeba that causes Acanthamoeba keratitis (AK) and granulomatous amebic encephalitis (GAE) in immunocompromised individuals. The biological and pathogenic characterizations behind this opportunistic protozoan is not fully understood. This study aimed to determine the biological functions of heat shock protein (HSP)-20 of A. castellanii (Ac-HSP20) involved in the maintenance of life cycle and the infectivity of A. castellanii. Immunoscreening A. castellanii cDNA library with A. castellanii infected rabbit sera identified three positive clones, one of them was a putative heat shock protein (Ac-HSP20). The recombinant 23 kDa Ac-HSP20 protein (rAc-HSP20) was successfully expressed in Escherichia coli BL21 (DE3) and purified using metal affinity chromatography. The rabbits immunized with rAc-HSP20 produced high titer antibody (1:25,600). Immunolocalization with the antibody identified the expression of native Ac-HSP20 on the surface of both A. castellanii trophozoites and cysts. Further, Western blot with antibody identified that the expression of native Ac-HSP20 was 7.5 times higher in cysts than in trophozoites. Blocking Ac-HSP20 on the membrane of trophozoites with specific antibody or silencing Ac-hsp20 gene transcription by siRNA inhibited their transformation into cysts at the early stage but returned to normal at the late stage by stimulating the transcription of Ac-hsp20. Incubation of trophozoites with anti-Ac-HSP20 IgG increased macrophage-involved phagocytosis to the protozoa and inhibited trophozoite infectivity on the cornea of rabbits compared with that without antibody. Our study provides that Ac-HSP20 is a surface antigen involved in the encystation and infectivity of A. castellanii and thus an important target for vaccine and drug development. Frontiers Media S.A. 2021-01-12 /pmc/articles/PMC7835678/ /pubmed/33510719 http://dx.doi.org/10.3389/fmicb.2020.595080 Text en Copyright © 2021 Wang, Sun, Liu, Jiang, Zheng, Zhu, Liu, Zheng and Feng. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. |
spellingShingle | Microbiology Wang, Ningning Sun, Hongyu Liu, Di Jiang, Xiaoming Zheng, Meiyu Zhu, Wenhe Liu, Quan Zheng, Wenyu Feng, Xianmin Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title | Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title_full | Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title_fullStr | Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title_full_unstemmed | Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title_short | Ac-HSP20 Is Associated With the Infectivity and Encystation of Acanthamoeba castellanii |
title_sort | ac-hsp20 is associated with the infectivity and encystation of acanthamoeba castellanii |
topic | Microbiology |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835678/ https://www.ncbi.nlm.nih.gov/pubmed/33510719 http://dx.doi.org/10.3389/fmicb.2020.595080 |
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