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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

Blood vessel and lymphatic vessel invasion events and sporozoite MSD in videos acquired with and without CD31-labeling of dermal vasculature.(A) No significant difference in the number of invasion events was observed in the presence or absence of CD31-labeling of vascular endothelia. (B) Mean square displacement (MSD) of sporozoite tracks over the duration of 4-min videos, at indicated time points after inoculation, showing comparable displacement of sporozoites in the dermis of mice with and without CD31 labeling. Dotted line shows 10 min time point data from Figure 1B, and solid lines shows the data used for that analysis split up into data from videos with CD31 labeling and videos without. The number of videos processed was: 10 min-all videos (14 videos/179 tracks), 10 min-without CD31 (10 videos/140 tracks), 10 min-with CD31 (4 videos/39 tracks).DOI:http://dx.doi.org/10.7554/eLife.07789.020
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fig5s1: Blood vessel and lymphatic vessel invasion events and sporozoite MSD in videos acquired with and without CD31-labeling of dermal vasculature.(A) No significant difference in the number of invasion events was observed in the presence or absence of CD31-labeling of vascular endothelia. (B) Mean square displacement (MSD) of sporozoite tracks over the duration of 4-min videos, at indicated time points after inoculation, showing comparable displacement of sporozoites in the dermis of mice with and without CD31 labeling. Dotted line shows 10 min time point data from Figure 1B, and solid lines shows the data used for that analysis split up into data from videos with CD31 labeling and videos without. The number of videos processed was: 10 min-all videos (14 videos/179 tracks), 10 min-without CD31 (10 videos/140 tracks), 10 min-with CD31 (4 videos/39 tracks).DOI:http://dx.doi.org/10.7554/eLife.07789.020

Mentions: Intravital microscopy of mutant CSΔN and TRAP-VAL sporozoites in conjunction with fluorescently labeled dermal vascular endothelia was performed, and invasion events were manually quantified (Figure 5E, Video 7 and Video 8). Invasion was classified as previously described (Amino et al., 2006), with blood vessel invasion defined by a sudden increase in speed or visual entry of the blood vessel and disappearance out of the field of view. It should be noted that the speed with which sporozoites appear to be carried out of the field is slower in videos that include CD31-labeling, as a result of the slower acquisition speed due to capture of two channels. Lymphatic invasion was defined by the switch from directed forward movement to sideward drifting with a low velocity. On average, in a 4-min video beginning at 10 min after inoculation, 2.38% of wild-type control sporozoites in the field of view enters the blood circulation, and 2.06% of sporozoites enters the lymphatic system (Figure 5E). Blood vessel invasion of the CSΔN mutant is reduced to 0.23% and only 0.05% of TRAP-VAL sporozoites is seen to enter into blood vessels (Figure 5E), which is consistent with the decrease in infectivity of these mutants upon intradermal inoculation (Coppi et al., 2011; Ejigiri et al., 2012). Invasion of the lymphatic system by CSΔN sporozoites is reduced to 0.26% and not detected at all in the case of TRAP-VAL sporozoites (Figure 5E). Importantly, CD31-labeling is not interfering with entry into dermal blood or lymphatic vessels or parasite dispersal, as vessel invasion rates, as well as sporozoite MSDs, are comparable in videos acquired in mice with and without labeled blood vessels (Figure 5—figure supplement 1).Video 7.Wild-type control sporozoites 10 min after intradermal inoculation together with CD31-labeled vascular endothelia highlighting blood and lymphatic vessel invasion events.


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)

Blood vessel and lymphatic vessel invasion events and sporozoite MSD in videos acquired with and without CD31-labeling of dermal vasculature.(A) No significant difference in the number of invasion events was observed in the presence or absence of CD31-labeling of vascular endothelia. (B) Mean square displacement (MSD) of sporozoite tracks over the duration of 4-min videos, at indicated time points after inoculation, showing comparable displacement of sporozoites in the dermis of mice with and without CD31 labeling. Dotted line shows 10 min time point data from Figure 1B, and solid lines shows the data used for that analysis split up into data from videos with CD31 labeling and videos without. The number of videos processed was: 10 min-all videos (14 videos/179 tracks), 10 min-without CD31 (10 videos/140 tracks), 10 min-with CD31 (4 videos/39 tracks).DOI:http://dx.doi.org/10.7554/eLife.07789.020
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Related In: Results  -  Collection

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fig5s1: Blood vessel and lymphatic vessel invasion events and sporozoite MSD in videos acquired with and without CD31-labeling of dermal vasculature.(A) No significant difference in the number of invasion events was observed in the presence or absence of CD31-labeling of vascular endothelia. (B) Mean square displacement (MSD) of sporozoite tracks over the duration of 4-min videos, at indicated time points after inoculation, showing comparable displacement of sporozoites in the dermis of mice with and without CD31 labeling. Dotted line shows 10 min time point data from Figure 1B, and solid lines shows the data used for that analysis split up into data from videos with CD31 labeling and videos without. The number of videos processed was: 10 min-all videos (14 videos/179 tracks), 10 min-without CD31 (10 videos/140 tracks), 10 min-with CD31 (4 videos/39 tracks).DOI:http://dx.doi.org/10.7554/eLife.07789.020
Mentions: Intravital microscopy of mutant CSΔN and TRAP-VAL sporozoites in conjunction with fluorescently labeled dermal vascular endothelia was performed, and invasion events were manually quantified (Figure 5E, Video 7 and Video 8). Invasion was classified as previously described (Amino et al., 2006), with blood vessel invasion defined by a sudden increase in speed or visual entry of the blood vessel and disappearance out of the field of view. It should be noted that the speed with which sporozoites appear to be carried out of the field is slower in videos that include CD31-labeling, as a result of the slower acquisition speed due to capture of two channels. Lymphatic invasion was defined by the switch from directed forward movement to sideward drifting with a low velocity. On average, in a 4-min video beginning at 10 min after inoculation, 2.38% of wild-type control sporozoites in the field of view enters the blood circulation, and 2.06% of sporozoites enters the lymphatic system (Figure 5E). Blood vessel invasion of the CSΔN mutant is reduced to 0.23% and only 0.05% of TRAP-VAL sporozoites is seen to enter into blood vessels (Figure 5E), which is consistent with the decrease in infectivity of these mutants upon intradermal inoculation (Coppi et al., 2011; Ejigiri et al., 2012). Invasion of the lymphatic system by CSΔN sporozoites is reduced to 0.26% and not detected at all in the case of TRAP-VAL sporozoites (Figure 5E). Importantly, CD31-labeling is not interfering with entry into dermal blood or lymphatic vessels or parasite dispersal, as vessel invasion rates, as well as sporozoite MSDs, are comparable in videos acquired in mice with and without labeled blood vessels (Figure 5—figure supplement 1).Video 7.Wild-type control sporozoites 10 min after intradermal inoculation together with CD31-labeled vascular endothelia highlighting blood and lymphatic vessel invasion events.

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