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Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition.

Hopp CS, Chiou K, Ragheb DR, Salman A, Khan SM, Liu AJ, Sinnis P - Elife (2015)

Bottom Line: How sporozoites locate and enter a blood vessel is a critical, but poorly understood process.Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained.Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States.

ABSTRACT
Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host. How sporozoites locate and enter a blood vessel is a critical, but poorly understood process. In this study, we examine sporozoite motility and their interaction with dermal blood vessels, using intravital microscopy in mice. Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained. We find that curvature of sporozoite tracks engaging with vasculature optimizes contact with dermal capillaries. Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.

No MeSH data available.


Related in: MedlinePlus

Anti-CD31 does not stain lymphatic vessels early after its inoculation.Dual live immunostaining for the lymphatic vessel hyaluronan receptor-1 and the panendothelial marker CD31. Lymphatic vessels (green) are labeled with anti-mouse LYVE-1 (clone ALY7, Affymetrix), inoculated intravenously 24 hr prior to imaging. Anti-mouse CD31 AF-64 was inoculated 3 hr prior to imaging and though blood vessels are stained (magenta), at this time point, lymphatic vessels remain unstained with anti-CD31.DOI:http://dx.doi.org/10.7554/eLife.07789.009
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fig2s1: Anti-CD31 does not stain lymphatic vessels early after its inoculation.Dual live immunostaining for the lymphatic vessel hyaluronan receptor-1 and the panendothelial marker CD31. Lymphatic vessels (green) are labeled with anti-mouse LYVE-1 (clone ALY7, Affymetrix), inoculated intravenously 24 hr prior to imaging. Anti-mouse CD31 AF-64 was inoculated 3 hr prior to imaging and though blood vessels are stained (magenta), at this time point, lymphatic vessels remain unstained with anti-CD31.DOI:http://dx.doi.org/10.7554/eLife.07789.009

Mentions: In order to exit the skin and enter the blood circulation, sporozoites must encounter and penetrate blood vessels. Although it was initially postulated that sporozoites might also reach the liver via the lymphatic vessels, a previous study found that sporozoites entering lymphatic vessels in the skin do not travel beyond the draining lymph node, and thus do not participate in liver stage infection (Amino et al., 2006; Radtke et al., 2015). To characterize the ability of sporozoites to engage with dermal vasculature, we visualized vascular endothelia by labeling the pan-endothelial junction molecule CD31 (also designated as platelet endothelial cell adhesion molecule 1, PECAM-1) by intravenous injection of fluorescently labeled rat anti-CD31 (Formaglio et al., 2014). CD31 is a member of the immunoglobulin superfamily and is present on the surface of endothelial cells of both lymphatics and blood vessels, where it is a constituent of intercellular junctions. However, as we performed our experiments within 2–3 hr of intravenous inoculation of anti-CD31, lymphatics were not labeled in our studies, since it takes ∼24 hr for intravenously inoculated antibody to get into the extravascular space and taken up by lymphatic vessels (Sarkisyan et al., 2012). This was confirmed by labeling lymphatic vessels with antibodies against the lymphatic vessel endothelial receptor 1 (LYVE-1) (Kilarski et al., 2013), which in the time frame of our experiments revealed no co-localization with CD31 (Figure 2—figure supplement 1). Additionally, lymphatic vessels, being wider and flatter and frequently possessing blind endings, have a different shape than blood vessels.


Longitudinal analysis of Plasmodium sporozoite motility in the dermis reveals component of blood vessel recognition.

Hopp CS, Chiou K, Ragheb DR, Salman A, Khan SM, Liu AJ, Sinnis P - Elife (2015)

Anti-CD31 does not stain lymphatic vessels early after its inoculation.Dual live immunostaining for the lymphatic vessel hyaluronan receptor-1 and the panendothelial marker CD31. Lymphatic vessels (green) are labeled with anti-mouse LYVE-1 (clone ALY7, Affymetrix), inoculated intravenously 24 hr prior to imaging. Anti-mouse CD31 AF-64 was inoculated 3 hr prior to imaging and though blood vessels are stained (magenta), at this time point, lymphatic vessels remain unstained with anti-CD31.DOI:http://dx.doi.org/10.7554/eLife.07789.009
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4594146&req=5

fig2s1: Anti-CD31 does not stain lymphatic vessels early after its inoculation.Dual live immunostaining for the lymphatic vessel hyaluronan receptor-1 and the panendothelial marker CD31. Lymphatic vessels (green) are labeled with anti-mouse LYVE-1 (clone ALY7, Affymetrix), inoculated intravenously 24 hr prior to imaging. Anti-mouse CD31 AF-64 was inoculated 3 hr prior to imaging and though blood vessels are stained (magenta), at this time point, lymphatic vessels remain unstained with anti-CD31.DOI:http://dx.doi.org/10.7554/eLife.07789.009
Mentions: In order to exit the skin and enter the blood circulation, sporozoites must encounter and penetrate blood vessels. Although it was initially postulated that sporozoites might also reach the liver via the lymphatic vessels, a previous study found that sporozoites entering lymphatic vessels in the skin do not travel beyond the draining lymph node, and thus do not participate in liver stage infection (Amino et al., 2006; Radtke et al., 2015). To characterize the ability of sporozoites to engage with dermal vasculature, we visualized vascular endothelia by labeling the pan-endothelial junction molecule CD31 (also designated as platelet endothelial cell adhesion molecule 1, PECAM-1) by intravenous injection of fluorescently labeled rat anti-CD31 (Formaglio et al., 2014). CD31 is a member of the immunoglobulin superfamily and is present on the surface of endothelial cells of both lymphatics and blood vessels, where it is a constituent of intercellular junctions. However, as we performed our experiments within 2–3 hr of intravenous inoculation of anti-CD31, lymphatics were not labeled in our studies, since it takes ∼24 hr for intravenously inoculated antibody to get into the extravascular space and taken up by lymphatic vessels (Sarkisyan et al., 2012). This was confirmed by labeling lymphatic vessels with antibodies against the lymphatic vessel endothelial receptor 1 (LYVE-1) (Kilarski et al., 2013), which in the time frame of our experiments revealed no co-localization with CD31 (Figure 2—figure supplement 1). Additionally, lymphatic vessels, being wider and flatter and frequently possessing blind endings, have a different shape than blood vessels.

Bottom Line: How sporozoites locate and enter a blood vessel is a critical, but poorly understood process.Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained.Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, United States.

ABSTRACT
Malaria infection starts with injection of Plasmodium sporozoites by an Anopheles mosquito into the skin of the mammalian host. How sporozoites locate and enter a blood vessel is a critical, but poorly understood process. In this study, we examine sporozoite motility and their interaction with dermal blood vessels, using intravital microscopy in mice. Our data suggest that sporozoites exhibit two types of motility: in regions far from blood vessels, they exhibit 'avascular motility', defined by high speed and less confinement, while in the vicinity of blood vessels their motility is more constrained. We find that curvature of sporozoite tracks engaging with vasculature optimizes contact with dermal capillaries. Imaging of sporozoites with mutations in key adhesive proteins highlight the importance of the sporozoite's gliding speed and its ability to modulate adhesive properties for successful exit from the inoculation site.

No MeSH data available.


Related in: MedlinePlus