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Molecular interactions that enable movement of the Lyme disease agent from the tick gut into the hemolymph.

Zhang L, Zhang Y, Adusumilli S, Liu L, Narasimhan S, Dai J, Zhao YO, Fikrig E - PLoS Pathog. (2011)

Bottom Line: The decreased hemolymph infection results in lower salivary glands infection, and consequently attenuates mouse infection by tick-transmitted B. burgdorferi.Silencing tre31 also decreased the B. burgdorferi burden in the tick hemolymph.Delineating the specific spirochete and arthropod ligands required for B. burgdorferi movement in the tick may lead to new strategies to interrupt the life cycle of the Lyme disease agent.

View Article: PubMed Central - PubMed

Affiliation: Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America.

ABSTRACT
Borrelia burgdorferi, the causative agent of Lyme disease, is transmitted to humans by bite of Ixodes scapularis ticks. The mechanisms by which the bacterium is transmitted from vector to host are poorly understood. In this study, we show that the F(ab)(2) fragments of BBE31, a B.burgdorferi outer-surface lipoprotein, interfere with the migration of the spirochete from tick gut into the hemolymph during tick feeding. The decreased hemolymph infection results in lower salivary glands infection, and consequently attenuates mouse infection by tick-transmitted B. burgdorferi. Using a yeast surface display approach, a tick gut protein named TRE31 was identified to interact with BBE31. Silencing tre31 also decreased the B. burgdorferi burden in the tick hemolymph. Delineating the specific spirochete and arthropod ligands required for B. burgdorferi movement in the tick may lead to new strategies to interrupt the life cycle of the Lyme disease agent.

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Related in: MedlinePlus

Subcellular localization of BBE31.(A) Protease digestion assay. Intact B. burgdorferi N40 cells were incubated with Protease K in the absence (-) or presence (+) of 0.05% Triton X-100. After digestion, cells were lysed and proteins were fractionated by SDS-PAGE. Immunoblots were developed with anti-BBE31 or anti-BB0365 (an inner membrane protein). 0, 20, 200: Protease K concentration is 0, 20 or 200 µg/ml. (B) Indirect immunofluorescence staining. Intact unfixed or methanol-fixed B. burgdorferi N40 were incubated with primary rabbit anti-BBE31 (right panels) or rabbit anti-BB0365 (left panels) antibodies, then incubated with the secondary antibodies Alexa 488-labelled goat anti-rabbit. Magnification, x63. Scale bar represents 20 µm.
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ppat-1002079-g002: Subcellular localization of BBE31.(A) Protease digestion assay. Intact B. burgdorferi N40 cells were incubated with Protease K in the absence (-) or presence (+) of 0.05% Triton X-100. After digestion, cells were lysed and proteins were fractionated by SDS-PAGE. Immunoblots were developed with anti-BBE31 or anti-BB0365 (an inner membrane protein). 0, 20, 200: Protease K concentration is 0, 20 or 200 µg/ml. (B) Indirect immunofluorescence staining. Intact unfixed or methanol-fixed B. burgdorferi N40 were incubated with primary rabbit anti-BBE31 (right panels) or rabbit anti-BB0365 (left panels) antibodies, then incubated with the secondary antibodies Alexa 488-labelled goat anti-rabbit. Magnification, x63. Scale bar represents 20 µm.

Mentions: Previous studies reported BBE31 as a B.burgorferi membrane protein [5]. To determine the exact localization of BBE31, both in situ proteolysis and indirect immunefluorescence assay (IFA) were carried out in this study. An inner membrane protein BB0365 was used as a negative control [15]. Surface-exposed proteins of intact bacteria can be degraded by proteases, whereas proteins not exposed to the surface are protected from proteolysis. In this work, when intact B.burgdorferi N40 were incubated with protease K, only BBE31 was degraded, while BB0365 was not (Figure 2A, lane 2 and lane 3). After disruption of B.burgdorferi cells by 0.05% Triton X-100, both proteins were completely degraded (Figure 2A, lane 5). These results indicate that BBE31 was degraded by protease K in the intact cells because of its outer-surface localization.


Molecular interactions that enable movement of the Lyme disease agent from the tick gut into the hemolymph.

Zhang L, Zhang Y, Adusumilli S, Liu L, Narasimhan S, Dai J, Zhao YO, Fikrig E - PLoS Pathog. (2011)

Subcellular localization of BBE31.(A) Protease digestion assay. Intact B. burgdorferi N40 cells were incubated with Protease K in the absence (-) or presence (+) of 0.05% Triton X-100. After digestion, cells were lysed and proteins were fractionated by SDS-PAGE. Immunoblots were developed with anti-BBE31 or anti-BB0365 (an inner membrane protein). 0, 20, 200: Protease K concentration is 0, 20 or 200 µg/ml. (B) Indirect immunofluorescence staining. Intact unfixed or methanol-fixed B. burgdorferi N40 were incubated with primary rabbit anti-BBE31 (right panels) or rabbit anti-BB0365 (left panels) antibodies, then incubated with the secondary antibodies Alexa 488-labelled goat anti-rabbit. Magnification, x63. Scale bar represents 20 µm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3111543&req=5

ppat-1002079-g002: Subcellular localization of BBE31.(A) Protease digestion assay. Intact B. burgdorferi N40 cells were incubated with Protease K in the absence (-) or presence (+) of 0.05% Triton X-100. After digestion, cells were lysed and proteins were fractionated by SDS-PAGE. Immunoblots were developed with anti-BBE31 or anti-BB0365 (an inner membrane protein). 0, 20, 200: Protease K concentration is 0, 20 or 200 µg/ml. (B) Indirect immunofluorescence staining. Intact unfixed or methanol-fixed B. burgdorferi N40 were incubated with primary rabbit anti-BBE31 (right panels) or rabbit anti-BB0365 (left panels) antibodies, then incubated with the secondary antibodies Alexa 488-labelled goat anti-rabbit. Magnification, x63. Scale bar represents 20 µm.
Mentions: Previous studies reported BBE31 as a B.burgorferi membrane protein [5]. To determine the exact localization of BBE31, both in situ proteolysis and indirect immunefluorescence assay (IFA) were carried out in this study. An inner membrane protein BB0365 was used as a negative control [15]. Surface-exposed proteins of intact bacteria can be degraded by proteases, whereas proteins not exposed to the surface are protected from proteolysis. In this work, when intact B.burgdorferi N40 were incubated with protease K, only BBE31 was degraded, while BB0365 was not (Figure 2A, lane 2 and lane 3). After disruption of B.burgdorferi cells by 0.05% Triton X-100, both proteins were completely degraded (Figure 2A, lane 5). These results indicate that BBE31 was degraded by protease K in the intact cells because of its outer-surface localization.

Bottom Line: The decreased hemolymph infection results in lower salivary glands infection, and consequently attenuates mouse infection by tick-transmitted B. burgdorferi.Silencing tre31 also decreased the B. burgdorferi burden in the tick hemolymph.Delineating the specific spirochete and arthropod ligands required for B. burgdorferi movement in the tick may lead to new strategies to interrupt the life cycle of the Lyme disease agent.

View Article: PubMed Central - PubMed

Affiliation: Section of Infectious Diseases, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut, United States of America.

ABSTRACT
Borrelia burgdorferi, the causative agent of Lyme disease, is transmitted to humans by bite of Ixodes scapularis ticks. The mechanisms by which the bacterium is transmitted from vector to host are poorly understood. In this study, we show that the F(ab)(2) fragments of BBE31, a B.burgdorferi outer-surface lipoprotein, interfere with the migration of the spirochete from tick gut into the hemolymph during tick feeding. The decreased hemolymph infection results in lower salivary glands infection, and consequently attenuates mouse infection by tick-transmitted B. burgdorferi. Using a yeast surface display approach, a tick gut protein named TRE31 was identified to interact with BBE31. Silencing tre31 also decreased the B. burgdorferi burden in the tick hemolymph. Delineating the specific spirochete and arthropod ligands required for B. burgdorferi movement in the tick may lead to new strategies to interrupt the life cycle of the Lyme disease agent.

Show MeSH
Related in: MedlinePlus