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A Comparative Approach to Characterize the Landscape of Host-Pathogen Protein-Protein Interactions
Published on: July 18, 2013
Spiroplasma eriocheiris Invasion Into Macrobrachium rosenbergii Hemocytes Is Mediated by Pathogen Enolase and Host
Mingxiao Ning1,2, Yunji Xiu1,2,3, Meijun Yuan1,2
1Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Marine Science and Engineering, Nanjing Normal University, Nanjing, China.
Abstract:
Spiroplasma eriocheiris is a crustacean pathogen, without a cell wall, that causes enormous economic loss. Macrobrachium rosenbergii hemocytes are the major targets during S. eriocheiris infection. As wall-less bacteria, S. eriocheiris, its membrane protein should interact with host membrane protein directly and firstly when invaded in host cell. In this investigation, six potential hemocyte receptor proteins were identified firstly that mediate interaction between S. eriocheiris and M. rosenbergii. Among these proteins, lipopolysaccharide and β-1, 3-glucan binding protein (MrLGBP) demonstrated to bind to S. eriocheiris using bacterial binding assays and confocal microscopy. Four spiroplasma ligand proteins for MrLGBP were isolated and identified. But, competitive assessment demonstrated that only enolase of S. eriocheiris (SeEnolase) could be a candidate ligand for MrLGBP. Subsequently, the interaction between MrLGBP and SeEnolase was confirmed by co-immunoprecipitation and co-localization in vitro. After the interaction between MrLGBP and SeEnolase was inhibited by antibody neutralization test, the virulence ability of S. eriocheiris was effectively reduced. The quantity of S. eriocheiris decreased in Drosophila S2 cells after overexpression of MrLGBP, compared with the controls. In addition, RNA interference (RNAi) knockdown of MrLGBP made M. rosenbergii more sensitive to S. eriocheiris infection. Further studies found that the immune genes, including MrLGBP and prophenoloxidase (MrproPO), MrRab7A, and Mrintegrin α1 were significantly up-regulated by SeEnolase stimulation. After SeEnolase pre-stimulation, the ability of M. rosenbergii resistance to S. eriocheiris was significantly improved. Collectively, this investigation demonstrated that MrLGBP and pathogen SeEnolase involved in mediating S. eriocheiris invasion into M. rosenbergii hemocytes.
Insights
Spiroplasma eriocheiris, a crustacean pathogen, invades Macrobrachium rosenbergii hemocytes via interactions between its enolase (SeEnolase) and the host
Area of Science:
- Aquatic animal health
- Microbiology
- Immunology
Background:
- Spiroplasma eriocheiris causes significant economic losses in crustaceans.
- Macrobrachium rosenbergii hemocytes are primary targets for S. eriocheiris infection.
- Understanding host-pathogen interactions is crucial for developing control strategies.
Purpose of the Study:
- To identify host receptor and pathogen ligand proteins mediating S. eriocheiris invasion.
- To elucidate the molecular mechanisms of interaction between S. eriocheiris and M. rosenbergii hemocytes.
- To evaluate the role of identified proteins in host defense and pathogen virulence.
Main Methods:
- Identification of hemocyte receptor proteins using bioinformatics and screening.
- Bacterial binding assays and confocal microscopy to confirm protein interactions.
- Co-immunoprecipitation, co-localization, antibody neutralization, and RNA interference (RNAi) to validate functional roles.
- Gene expression analysis to assess immune response.
Main Results:
- Six potential hemocyte receptor proteins were identified; MrLGBP specifically bound S. eriocheiris.
- S. eriocheiris enolase (SeEnolase) was identified as the primary ligand for MrLGBP.
- Inhibition of MrLGBP-SeEnolase interaction reduced S. eriocheiris virulence and invasion.
- Overexpression of MrLGBP reduced pathogen load, while MrLGBP knockdown increased host susceptibility.
- SeEnolase stimulation upregulated key immune genes and enhanced host resistance.
Conclusions:
- MrLGBP and SeEnolase are critical mediators of S. eriocheiris invasion into M. rosenbergii hemocytes.
- The MrLGBP-SeEnolase interaction represents a potential target for controlling S. eriocheiris infections.
- SeEnolase plays a dual role, facilitating invasion while also triggering host immune responses.
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