Acanthamoeba-mediated cytopathic effect correlates with MBP and AhLBP mRNA expression

Ng, Sook-Luan; Nordin, Anisah; Ghafar, Norzana Abd; Suboh, Yusof; Rahim, Noraina Ab; Chua, Kien Hui

doi:10.1186/s13071-017-2547-0

Cited by 17 publications

(14 citation statements)

References 60 publications

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“…Pathogenic Acanthamoeba interacts with host cells through the glycocalyx, the main carbohydrate-containing component of the cell membrane [41,44]. Thus, several adhesins including a >207 kDa adhesin [222], a mannose-binding protein (MBP) [223] and a laminin-binding protein (AhLBP) [224], contribute to trophozoites attachment by interacting with glycoproteins and glycolipids present on the corneal surface [44].…”

Section: Acanthamoeba Sppmentioning

confidence: 99%

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Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins

Betanzos

Bañuelos

Orozco

2019

Genes

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The epithelium represents the first and most extensive line of defence against pathogens, toxins and pollutant agents in humans. In general, pathogens have developed strategies to overcome this barrier and use it as an entrance to the organism. Entamoeba histolytica, Naegleria fowleri and Acanthamoeba spp. are amoebae mainly responsible for intestinal dysentery, meningoencephalitis and keratitis, respectively. These amoebae cause significant morbidity and mortality rates. Thus, the identification, characterization and validation of molecules participating in host-parasite interactions can provide attractive targets to timely intervene disease progress. In this work, we present a compendium of the parasite adhesins, lectins, proteases, hydrolases, kinases, and others, that participate in key pathogenic events. Special focus is made for the analysis of assorted molecules and mechanisms involved in the interaction of the parasites with epithelial surface receptors, changes in epithelial junctional markers, implications on the barrier function, among others. This review allows the assessment of initial host-pathogen interaction, to correlate it to the potential of parasite invasion.

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Section: Acanthamoeba Sppmentioning

confidence: 99%

“…Besides, A. healyi adhere via AhLBP (55 kDa) to the Bowman’s layer and ECM components (laminin, collagen type I), which underlie the basal lamina [224,228]. Similarly, A. polyphaga binds to laminin, collagen IV and fibronectin in a mannose- and calcium-dependent manner [229,230].…”

Section: Acanthamoeba Sppmentioning

confidence: 99%

Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins

Betanzos

Bañuelos

Orozco

2019

Genes

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“…The first stage of Acanthamoeba infection is the interaction between mannose binding protein (MBP) on the surface of the parasite and the mannosylated proteins on the surface of host cells [ 4 ]. Next, a variety of proteolytic enzymes are secreted into the host, hydrolysing the host’s tissue and resulting in tissue oedema, inflammation and necrosis [ 5 ]. Among these enzymes, serine proteases [ 6 ] and cysteine proteases (CPs) [ 7 ] are the main proteolytic proteins.…”

Section: Introductionmentioning

confidence: 99%

Identification and biochemical characterisation of Acanthamoeba castellanii cysteine protease 3

Wang

Tachibana

et al. 2020

Parasites Vectors

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Background Acanthamoeba spp. are free-living amoeba that are ubiquitously distributed in the environment. This study examines pathogenic Acanthamoeba cysteine proteases (AcCPs) belonging to the cathepsin L-family and explores the mechanism of AcCP3 interaction with host cells. Methods Six AcCP genes were amplified by polymerase chain reaction (PCR). Quantitative real-time PCR was used to analyse the relative mRNA expression of AcCPs during the encystation process and between pre- and post-reactivated trophozoites. To further verify the role of AcCP3 in these processes, AcCP3 recombinant proteins were expressed in Escherichia coli, and the hydrolytic activity of AcCP3 was determined. The influence of the AcCP3 on the hydrolytic activity of trophozoites and the toxicity of trophozoites to human corneal epithelial cells (HCECs) was examined by inhibiting AcCP3 expression using siRNA. Furthermore, the levels of p-Raf and p-Erk were examined in HCECs following coculture with AcCP3 gene knockdown trophozoites by Western blotting. Results During encystation, five out of six AcCPs exhibited decreased expression, and only AcCP6 was substantially up-regulated at the mRNA level, indicating that most AcCPs were not directly correlated to encystation. Furthermore, six AcCPs exhibited increased expression level following trophozoite reactivation with HEp-2 cells, particularly AcCP3, indicating that these AcCPs might be virulent factors. After refolding of recombinant AcCP3 protein, the 27 kDa mature protein from the 34 kDa pro-protein hydrolysed host haemoglobin, collagen and albumin and showed high activity in an acidic environment. After AcCP3 knockdown, the hydrolytic activity of trophozoite crude protein against gelatin was decreased, suggesting that these trophozoites had decreased toxicity. Compared with untreated trophozoites or negative control siRNA-treated trophozoites, AcCP3-knockdown trophozoites were less able to penetrate and damage monolayers of HCECs. Western blot analysis showed that the activation levels of the Ras/Raf/Erk/p53 signalling pathways in HCECs decreased after inhibiting the expression of trophozoite AcCP3. Conclusions AcCP6 was correlated to encystation. Furthermore, AcCP3 was a virulent factor in trophozoites and participated in the activation of the Ras/Raf/Erk/p53 signalling pathways of host cells.

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“…The rst stage of Acanthamoeba infection is the interaction between mannose binding protein (MBP) on the surface of the parasite and the mannosylated proteins on the surface of host cells [4]. Next, a variety of proteolytic enzymes are secreted into the host, hydrolysing the host's tissue and resulting in tissue oedema, in ammation and necrosis [5]. Among these enzymes, serine proteases [6] and cysteine proteases (CPs) [7] are the main proteolytic proteins.…”

Section: Introductionmentioning

confidence: 99%

Identification and biochemical characterisation of Acanthamoeba castellanii cysteine protease 3

Wang

Tachibana

et al. 2020

Preprint

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Background: Acanthamoeba spp. are free-living amoeba that are ubiquitously distributed in the environment. This study examines pathogenic Acanthamoeba cysteine proteases (AcCPs) belonging to the cathepsin L-family and explores the mechanism of AcCP3 interaction with host cells.Methods: Six AcCP genes were amplified by polymerase chain reaction (PCR). Quantitative real-time PCR was used to analyse the relative mRNA expression of AcCPs during the encystation process, and between pre- and post-reactivated trophozoites. To further verify the role of AcCP3 in these processes, AcCP3 recombinant proteins were expressed in Escherichia coli, and the hydrolytic activity of AcCP3 was determined. The influence of the AcCP3 on the hydrolytic activity of trophozoites and the toxicity of trophozoites to human corneal epithelial cells (HCECs) was examined by inhibiting AcCP3 expression using siRNA. Further, the levels of p-Raf and p-Erk were examined in HCECs following coculture with AcCP3 gene knockdown trophozoites by western blotting.Results: During encystation, five out of six AcCPs exhibited decreased expression, and only AcCP6 was substantially up-regulated at the mRNA level, indicating that most AcCPs were not directly correlated to encystation. Further, six AcCPs exhibited increased expression level following trophozoite reactivation with HEp-2 cells, particularly AcCP3, indicating that these AcCPs might be virulent factors. After refolding of recombinant AcCP3 protein, the 27 kDa mature protein from the 34 kDa pro-protein hydrolysed host haemoglobin, collagen and albumin, and showed high activity in an acidic environment. After AcCP3 knockdown, the hydrolytic activity of trophozoite crude protein against gelatin was decreased, suggesting that these trophozoite had decreased toxicity. Compared with untreated trophozoites or negative control siRNA-treated trophozoites, AcCP3-knockdown trophozoites were less able to penetrate and damage monolayers of HCECs. Western blot analysis showed that the activation levels of the Ras/Raf/Erk/p53 signalling pathways in HCECs decreased after inhibiting the expression of trophozoite AcCP3.Conclusions: AcCP6 was correlated to encystation. Further, AcCP3 was a virulent factor in trophozoites, and participated in the activation of the Ras/Raf/Erk/p53 signalling pathways of host cells.

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Acanthamoeba-mediated cytopathic effect correlates with MBP and AhLBP mRNA expression

Cited by 17 publications

References 60 publications

Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins

Host Invasion by Pathogenic Amoebae: Epithelial Disruption by Parasite Proteins

Identification and biochemical characterisation of Acanthamoeba castellanii cysteine protease 3

Identification and biochemical characterisation of Acanthamoeba castellanii cysteine protease 3

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