Comparison of Proteins Secreted into Extracellular Space of Pathogenic and Non-pathogenic Acanthamoeba castellanii

Abstract

Pathogenic Acanthamoeba spp. cause granulomatous amoebic encephalitis and keratitis. Acanthamoeba keratitis (AK) is a rare but serious ocular infection that can result in permanent visual impairment or blindness. However, pathogenic factors of AK remain unclear and treatment for AK is arduous. Expression levels of proteins secreted into extracellular space were compared between A. castellanii pathogenic (ACP) and non-pathogenic strains. Two-dimensional polyacrylamide gel electrophoresis revealed 123 differentially expressed proteins, including 34 increased proteins, 7 qualitative increased proteins, 65 decreased proteins, and 17 qualitative decreased proteins in ACP strain. Twenty protein spots with greater than 5-fold increase in ACP strain were analyzed by liquid chromatography triple quadrupole mass spectrometry. These proteins showed similarity each to inosine-uridine preferring nucleoside hydrolase, carboxylesterase, oxygen-dependent choline dehydrogenase, periplasmic-binding protein proteinases and hypothetical proteins. These proteins expressed higher in ACP may provide some information to understand pathogenicity of Acanthamoeba.

Quantitative proteomic analysis and functional characterization of Acanthamoeba castellanii exosome-like vesicles

“…Hence, the biological significance of IUNH in free-living protozoans remains to be determined. Comparative proteomic analysis of proteins secreted into the extracellular space of pathogenic and non-pathogenic A. castellanii also revealed that IUNH is upregulated more than 5-fold in the pathogenic strain [51]. It is worth investigating whether IUNH in EVs plays a crucial role in the pathogenesis of A. castellanii .…”

Production of a polyclonal antibody against inosine-uridine preferring nucleoside hydrolase of Acanthamoeba castellanii and its access to diagnosis of Acanthamoeba keratitis

“…IPNH of A. castellanii has signal peptides and transmembrane domain (Fig 1), which signify that the protein may be easily secreted from the trophozoites of Acanthamoeba. In support of this, the pathogenic strain of A. castellanii has been found to secrete a large amount of IPNH proteins [23]. From this finding, we hypothesized that measurable quantities of IPNH proteins are discharged through the tears of AK patients which implies that the IPNH antigen present in tears can be used for AK diagnosis.…”

“…In support of this, the pathogenic strain of A . castellanii has been found to secrete a large amount of IPNH proteins [ 23 ]. From this finding, we hypothesized that measurable quantities of IPNH proteins are discharged through the tears of AK patients which implies that the IPNH antigen present in tears can be used for AK diagnosis.…”

“…In our previous investigation, secretory proteins of A. castellanii non-pathogenic strain and pathogenic strain were compared by 2-dimensional polyacrylamide gel electrophoresis [23]. In that study, one protein among 41 up-regulated proteins in the pathogenic strain was selected (S1 Fig).…”

“…In the previous study, expression levels of secretory proteins were compared between non-pathogenic and pathogenic strains of A . castellanii , and pathogenic strain revealed 34 increased proteins and 7 qualitatively increased proteins [ 23 ]. Among 34 increased proteins of pathogenic Acanthamoeba , inosine-uridine preferring nucleoside hydrolase (IPNH) was selected for further work.…”