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Leishmania infection modulates beta-1 integrin activation and alters the kinetics of monocyte spreading over fibronectin.

Figueira CP, Carvalhal DG, Almeida RA, Hermida Md, Touchard D, Robert P, Pierres A, Bongrand P, dos-Santos WL - Sci Rep (2015)

Bottom Line: Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue.This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody.These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Fundação Oswaldo Cruz-Bahia, Centro de Pesquisas Gonçalo Moniz, Brazilian Ministry of Health, Salvador, Brazil.

ABSTRACT
Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue. In this work, we studied the early stages of bond formation between VLA4 and fibronectin, measured the kinetics of membrane alignment and the monocyte cytoplasm spreading area over a fibronectin-coated surface, and studied the expression of high affinity integrin epitope in uninfected and Leishmania-infected human monocytes. Our results show that the initial VLA4-mediated interaction of Leishmania-infected monocyte with a fibronectin-coated surface is preserved, however, the later stage, leukocyte spreading over the substrate is abrogated in Leishmania-infected cells. The median of spreading area was 72 [55-89] μm(2) for uninfected and 41 [34-51] μm(2) for Leishmania-infected monocyte. This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody. After the initial contact with the fibronectrin-coated surface, uninfected monocyte quickly spread the cytoplasm at a 15 μm(2) s(-1) ratio whilst Leishmania-infected monocytes only made small contacts at a 5.5 μm(2) s(-1) ratio. The expression of high affinity epitope by VLA4 (from 39 ± 21% to 14 ± 3%); and LFA1 (from 37 ± 32% to 18 ± 16%) molecules was reduced in Leishmania-infected monocytes. These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.

No MeSH data available.


Related in: MedlinePlus

High-affinity LFA1 epitope expression on infected monocytes.For single-color staining, 1 × 106 monocytes were cultured in medium alone or in medium containing Leishmania. The cells were resuspended in medium alone (A) or in medium containing Mn++ (B). The cells were then stained with a specific LFA1 high-affinity epitope marker and analyzed by flow cytometry. Empty histograms cells incubated with isotype control antibody. Grey histograms cells incubated with the anti-LFA1 high affinity epitope antibody. Scatterplots: Each pair of data connected by line represents an independent experiment using the same batch of monocytes, cultured with medium alone (Control) or with medium containing Leishmania (Infected) (Not significant Mann-Whitney test).
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f7: High-affinity LFA1 epitope expression on infected monocytes.For single-color staining, 1 × 106 monocytes were cultured in medium alone or in medium containing Leishmania. The cells were resuspended in medium alone (A) or in medium containing Mn++ (B). The cells were then stained with a specific LFA1 high-affinity epitope marker and analyzed by flow cytometry. Empty histograms cells incubated with isotype control antibody. Grey histograms cells incubated with the anti-LFA1 high affinity epitope antibody. Scatterplots: Each pair of data connected by line represents an independent experiment using the same batch of monocytes, cultured with medium alone (Control) or with medium containing Leishmania (Infected) (Not significant Mann-Whitney test).

Mentions: To determine whether this disturbance in the integrin configuration was restricted to VLA4 or was a more generalized effect of Leishmania infection, we studied the expression of the high-affinity epitope of LFA1, a beta-2 integrin expressed by leukocytes. The expression of the LFA1 high-affinity epitope was lower in Leishmania-infected monocytes (18 ± 16%) than in uninfected monocytes (37 ± 32%, Fig. 7A). Even after stimulation with Mn++, the expression of the LFA1 high-affinity epitope remained lower in the Leishmania-infected monocytes (52 ± 13%) than in the uninfected monocytes (67 ± 20%); however, this difference was not statistically significant (Fig. 7B).


Leishmania infection modulates beta-1 integrin activation and alters the kinetics of monocyte spreading over fibronectin.

Figueira CP, Carvalhal DG, Almeida RA, Hermida Md, Touchard D, Robert P, Pierres A, Bongrand P, dos-Santos WL - Sci Rep (2015)

High-affinity LFA1 epitope expression on infected monocytes.For single-color staining, 1 × 106 monocytes were cultured in medium alone or in medium containing Leishmania. The cells were resuspended in medium alone (A) or in medium containing Mn++ (B). The cells were then stained with a specific LFA1 high-affinity epitope marker and analyzed by flow cytometry. Empty histograms cells incubated with isotype control antibody. Grey histograms cells incubated with the anti-LFA1 high affinity epitope antibody. Scatterplots: Each pair of data connected by line represents an independent experiment using the same batch of monocytes, cultured with medium alone (Control) or with medium containing Leishmania (Infected) (Not significant Mann-Whitney test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4528201&req=5

f7: High-affinity LFA1 epitope expression on infected monocytes.For single-color staining, 1 × 106 monocytes were cultured in medium alone or in medium containing Leishmania. The cells were resuspended in medium alone (A) or in medium containing Mn++ (B). The cells were then stained with a specific LFA1 high-affinity epitope marker and analyzed by flow cytometry. Empty histograms cells incubated with isotype control antibody. Grey histograms cells incubated with the anti-LFA1 high affinity epitope antibody. Scatterplots: Each pair of data connected by line represents an independent experiment using the same batch of monocytes, cultured with medium alone (Control) or with medium containing Leishmania (Infected) (Not significant Mann-Whitney test).
Mentions: To determine whether this disturbance in the integrin configuration was restricted to VLA4 or was a more generalized effect of Leishmania infection, we studied the expression of the high-affinity epitope of LFA1, a beta-2 integrin expressed by leukocytes. The expression of the LFA1 high-affinity epitope was lower in Leishmania-infected monocytes (18 ± 16%) than in uninfected monocytes (37 ± 32%, Fig. 7A). Even after stimulation with Mn++, the expression of the LFA1 high-affinity epitope remained lower in the Leishmania-infected monocytes (52 ± 13%) than in the uninfected monocytes (67 ± 20%); however, this difference was not statistically significant (Fig. 7B).

Bottom Line: Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue.This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody.These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Fundação Oswaldo Cruz-Bahia, Centro de Pesquisas Gonçalo Moniz, Brazilian Ministry of Health, Salvador, Brazil.

ABSTRACT
Contact with Leishmania leads to a decreases in mononuclear phagocyte adherence to connective tissue. In this work, we studied the early stages of bond formation between VLA4 and fibronectin, measured the kinetics of membrane alignment and the monocyte cytoplasm spreading area over a fibronectin-coated surface, and studied the expression of high affinity integrin epitope in uninfected and Leishmania-infected human monocytes. Our results show that the initial VLA4-mediated interaction of Leishmania-infected monocyte with a fibronectin-coated surface is preserved, however, the later stage, leukocyte spreading over the substrate is abrogated in Leishmania-infected cells. The median of spreading area was 72 [55-89] μm(2) for uninfected and 41 [34-51] μm(2) for Leishmania-infected monocyte. This cytoplasm spread was inhibited using an anti-VLA4 blocking antibody. After the initial contact with the fibronectrin-coated surface, uninfected monocyte quickly spread the cytoplasm at a 15 μm(2) s(-1) ratio whilst Leishmania-infected monocytes only made small contacts at a 5.5 μm(2) s(-1) ratio. The expression of high affinity epitope by VLA4 (from 39 ± 21% to 14 ± 3%); and LFA1 (from 37 ± 32% to 18 ± 16%) molecules was reduced in Leishmania-infected monocytes. These changes in phagocyte function may be important for parasite dissemination and distribution of lesions in leishmaniasis.

No MeSH data available.


Related in: MedlinePlus