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Sialic acid expression in the mosquito Aedes aegypti and its possible role in dengue virus-vector interactions.

Cime-Castillo J, Delannoy P, Mendoza-Hernández G, Monroy-Martínez V, Harduin-Lepers A, Lanz-Mendoza H, Hernández-Hernández Fde L, Zenteno E, Cabello-Gutiérrez C, Ruiz-Ordaz BH - Biomed Res Int (2015)

Bottom Line: AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface.Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome.Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology and Biotechnology Department, Biomedical Research Institute, National University of México (UNAM), 04510 México City, Mexico.

ABSTRACT
Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission.

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Lectin histochemistry of Ae. aegypti tissues. (a) Results of α-2,6-linked Sia detection in Ae. aegypti SG, midgut, and head incubated with SNA lectin (1 : 100) and stained with FITC. SG, upper panel: 60x microscopic magnification, lower panel: 40x lens. The inner box in the SG-DAPI panel shows the SG region analyzed. To identify Sia, the midgut and head transverse sections were evaluated with SNA lectin (green) (20x magnification). (b) Results for the α-2,6-linked Sia positive control in D. melanogaster abdomen, gut, and midgut using SNA lectin, which are similar to those for Ae. aegypti tissues. (c) SNA staining of mosquito SG and midgut pretreated with 0.5 IU sialidase for 30 min before SNA incubation. The control comprised D. melanogaster heads pretreated with sialidase. Blue: nuclei stained with DAPI. Green: (FITC) SNA lectin interaction.
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fig2: Lectin histochemistry of Ae. aegypti tissues. (a) Results of α-2,6-linked Sia detection in Ae. aegypti SG, midgut, and head incubated with SNA lectin (1 : 100) and stained with FITC. SG, upper panel: 60x microscopic magnification, lower panel: 40x lens. The inner box in the SG-DAPI panel shows the SG region analyzed. To identify Sia, the midgut and head transverse sections were evaluated with SNA lectin (green) (20x magnification). (b) Results for the α-2,6-linked Sia positive control in D. melanogaster abdomen, gut, and midgut using SNA lectin, which are similar to those for Ae. aegypti tissues. (c) SNA staining of mosquito SG and midgut pretreated with 0.5 IU sialidase for 30 min before SNA incubation. The control comprised D. melanogaster heads pretreated with sialidase. Blue: nuclei stained with DAPI. Green: (FITC) SNA lectin interaction.

Mentions: The Ae. aegypti ST gene is related to the ST6Gal family [37]; thus, we evaluated gene expression based on the presence of α-2,6-Neu5Ac moieties on the surface of mosquito tissues (SG, head, and midguts) using affinocytochemistry and confocal microscopy assays with the lectin SNA, which recognizes Sia in α-2,6-linkages. We observed strong SNA staining in the different mosquito samples (Figure 2(a)). D. melanogaster tissues were used as the positive control and are well known [15] to express α-2,6-linked Neu5Ac moieties (Figure 2(b)). No MAA binding was observed in Ae. aegypti tissues, which indicates that Ae. aegypti does not express α-2,3-ST (similar to D. melanogaster, Figure S2). To validate the SNA binding assay, SGs were pretreated with C. perfringens sialidase and incubated with SNA lectin. In the absence of sialidase treatment, strong SNA staining was observed in Ae. aegypti mosquito and D. melanogaster tissues (Figures 2(a) and 2(b)). However, the SNA binding decreased after sialidase treatment of the mosquito and D. melanogaster tissues (Figure 2(c)).


Sialic acid expression in the mosquito Aedes aegypti and its possible role in dengue virus-vector interactions.

Cime-Castillo J, Delannoy P, Mendoza-Hernández G, Monroy-Martínez V, Harduin-Lepers A, Lanz-Mendoza H, Hernández-Hernández Fde L, Zenteno E, Cabello-Gutiérrez C, Ruiz-Ordaz BH - Biomed Res Int (2015)

Lectin histochemistry of Ae. aegypti tissues. (a) Results of α-2,6-linked Sia detection in Ae. aegypti SG, midgut, and head incubated with SNA lectin (1 : 100) and stained with FITC. SG, upper panel: 60x microscopic magnification, lower panel: 40x lens. The inner box in the SG-DAPI panel shows the SG region analyzed. To identify Sia, the midgut and head transverse sections were evaluated with SNA lectin (green) (20x magnification). (b) Results for the α-2,6-linked Sia positive control in D. melanogaster abdomen, gut, and midgut using SNA lectin, which are similar to those for Ae. aegypti tissues. (c) SNA staining of mosquito SG and midgut pretreated with 0.5 IU sialidase for 30 min before SNA incubation. The control comprised D. melanogaster heads pretreated with sialidase. Blue: nuclei stained with DAPI. Green: (FITC) SNA lectin interaction.
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Related In: Results  -  Collection

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fig2: Lectin histochemistry of Ae. aegypti tissues. (a) Results of α-2,6-linked Sia detection in Ae. aegypti SG, midgut, and head incubated with SNA lectin (1 : 100) and stained with FITC. SG, upper panel: 60x microscopic magnification, lower panel: 40x lens. The inner box in the SG-DAPI panel shows the SG region analyzed. To identify Sia, the midgut and head transverse sections were evaluated with SNA lectin (green) (20x magnification). (b) Results for the α-2,6-linked Sia positive control in D. melanogaster abdomen, gut, and midgut using SNA lectin, which are similar to those for Ae. aegypti tissues. (c) SNA staining of mosquito SG and midgut pretreated with 0.5 IU sialidase for 30 min before SNA incubation. The control comprised D. melanogaster heads pretreated with sialidase. Blue: nuclei stained with DAPI. Green: (FITC) SNA lectin interaction.
Mentions: The Ae. aegypti ST gene is related to the ST6Gal family [37]; thus, we evaluated gene expression based on the presence of α-2,6-Neu5Ac moieties on the surface of mosquito tissues (SG, head, and midguts) using affinocytochemistry and confocal microscopy assays with the lectin SNA, which recognizes Sia in α-2,6-linkages. We observed strong SNA staining in the different mosquito samples (Figure 2(a)). D. melanogaster tissues were used as the positive control and are well known [15] to express α-2,6-linked Neu5Ac moieties (Figure 2(b)). No MAA binding was observed in Ae. aegypti tissues, which indicates that Ae. aegypti does not express α-2,3-ST (similar to D. melanogaster, Figure S2). To validate the SNA binding assay, SGs were pretreated with C. perfringens sialidase and incubated with SNA lectin. In the absence of sialidase treatment, strong SNA staining was observed in Ae. aegypti mosquito and D. melanogaster tissues (Figures 2(a) and 2(b)). However, the SNA binding decreased after sialidase treatment of the mosquito and D. melanogaster tissues (Figure 2(c)).

Bottom Line: AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface.Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome.Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues.

View Article: PubMed Central - PubMed

Affiliation: Molecular Biology and Biotechnology Department, Biomedical Research Institute, National University of México (UNAM), 04510 México City, Mexico.

ABSTRACT
Dengue fever (DF) is the most prevalent arthropod-borne viral disease which affects humans. DF is caused by the four dengue virus (DENV) serotypes, which are transmitted to the host by the mosquito Aedes aegypti that has key roles in DENV infection, replication, and viral transmission (vector competence). Mosquito saliva also plays an important role during DENV transmission. In this study, we detected the presence of sialic acid (Sia) in Aedes aegypti tissues, which may have an important role during DENV-vector competence. We also identified genome sequences encoding enzymes involved in Sia pathways. The cDNA for Aedes aegypti CMP-Sia synthase (CSAS) was amplified, cloned, and functionally evaluated via the complementation of LEC29.Lec32 CSAS-deficient CHO cells. AedesCSAS-transfected LEC29.Lec32 cells were able to express Sia moieties on the cell surface. Sequences related to α-2,6-sialyltransferase were detected in the Aedes aegypti genome. Likewise, we identified Sia-α-2,6-DENV interactions in different mosquito tissues. In addition, we evaluated the possible role of sialylated molecules in a salivary gland extract during DENV internalization in mammalian cells. The knowledge of early DENV-host interactions could facilitate a better understanding of viral tropism and pathogenesis to allow the development of new strategies for controlling DENV transmission.

Show MeSH
Related in: MedlinePlus