Functional characterization of a serine protease inhibitor modulated in the infection of the Aedes aegypti with dengue virus

Author(s)

Soares, Tatiane Sanches ^[1] ; Rodriguez Gonzalez, Boris Luis ^[1] ; Soares Torquato, Ricardo Jose ^[1] ; Alves Lemos, Francisco Jose ^[2] ; Costa-da-Silva, Andre L. ^[3] ; Capurro Guimaraes, Margareth de Lara ^[3] ; Tanaka, Aparecida Sadae ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Escola Paulista Med, Dept Bioquim, Rua 3 Maio 100, BR-04044020 Sao Paulo, SP - Brazil

^[2] Univ Estadual Norte Fluminense, Lab Biotecnol, Rio De Janeiro, RJ - Brazil

^[3] Univ Sao Paulo, Inst Ciencias Biomed, Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Biochimie; v. 144, p. 160-168, JAN 2018.
• Web of Science Citations: 4

Abstract

During feeding with blood meal, female Aedes aegypti can transmit infectious agents, such as dengue, yellow fever, chikungunya and Zika viruses. Dengue virus causes human mortality in tropical regions of the world, and there is no specific treatment or vaccine with maximum efficiency being used for these infections. In the vector-virus interaction, the production of several molecules is modulated by both mosquitoes and invading agents. However, little information is available about these molecules in the Ae. aegypti mosquito during dengue infection. Inhibitors of the pacifastin family have been described to participate in the immune response of insects and Pac2 is the only gene of this family present in Ae. aegypti being then chosen for investigation. Pac2 was expressed in E. coli, purified and analyzed by mass spectrometry and SDS-PAGE. The Pac2 transcript was detected by qPCR, and its protein levels were assessed by Western blotting. The inhibitory activity of Pac2 was measured using its K-i, IC50 and zymography. Mosquito infections with DENV were introduced with the Brazilian ACS-46 DENV-2 strain propagated in C6/36 cells. In the present work, we showed that it is possibly involved in the interaction of the mosquitoes with the dengue virus. The Pac2 transcript was detected in larvae and in both the salivary gland and midgut of Ae. aegypti females, while the native protein was identified in females 3 h post-blood meal. Pac2 is a strong inhibitor of trypsin-like and thrombin-like proteases, which are present in 4th instar larvae midgut and females 24 h after blood meal. During DENV infection, up regulation of Pac2 expression occurs in the salivary gland and midgut. Pac2 is the first Pacifastin inhibitor member described in mosquitoes. Our results suggest that Pac2 acts on mosquito serine proteases, mainly the trypsin-like type, and is under transcriptional control by virus infection signals to allow its survival in the vector or by the mosquito as a defense mechanism against virus infection. (C) 2017 Elsevier B.V. and Societe Francaise de Biochimie et Biologie Moleculaire (SFBBM). All rights reserved. (AU)

• FAPESP's process: 12/15191-3 - Functional characterization of serine protease inhibitors present in mosquito Aedes aegypti infected and not infected with dengue virus
• Grantee: Tatiane Sanches Soares
• Support type: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 12/03657-8 - Inhibitor and proteases of ectoparasites: relationship of structure-function and identification of the role of these molecules in the interaction of diseases vector e their etiological agents
• Grantee: Aparecida Sadae Tanaka
• Support type: Research Projects - Thematic Grants