Structural determination of the interaction between dengue virus NS1 and human prothrombin/thrombin: mapping critical exosites in the modulation of blood coagulation during infection

• Grant number: 25/02869-1
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date: September 01, 2025
• End date: August 31, 2026
• Field of knowledge: Biological Sciences - Biophysics - Molecular Biophysics
• Principal Investigator: Paula Rahal
• Grantee: Carolina Gismene
• Supervisor: Sriram Krishnaswamy
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil
• Institution abroad: Children's Hospital of Philadelphia (CHOP), United States
• Associated to the scholarship: 24/00876-8 - Protein exosites, cryptic sites and moonlighting: identification, functional mapping and effects of changes in structure, BP.PD

Abstract

Dengue is a viral disease that poses an increasing threat to global public health, particularly in tropical and subtropical regions. Caused by the dengue virus (DENV) and transmitted by Aedes mosquitoes, the infection affects millions of people annually. Despite advancements such as the development of the Dengvaxia vaccine, its efficacy remains limited, especially in preventing severe cases like dengue hemorrhagic fever (DHF), underscoring the ongoing need for new treatments and prophylactic approaches. In this context, the dengue virus non-structural protein 1 (NS1) emerges as a promising target for scientific research due to its multifaceted role as a viral virulence factor. Unlike NS1 from other Flaviviridae family viruses, such as Zika virus (ZIKV) and Yellow Fever virus (YFV), DENV-NS1 has been shown to interact with blood coagulation factors, including prothrombin and thrombin, aligning with the virus's ability to cause DHF. However, the specific domains of these proteins involved in such interactions, as well as the mechanistic pathways that facilitate the binding between NS1-prothrombin and NS1-thrombin, remain unknown. Moreover, the implications of these interactions on blood coagulation are not yet fully understood. Given these gaps, the primary objective of this research project is to investigate the molecular steps underlying the association of DENV-NS1 with human prothrombin and thrombin by mapping critical exosites that modulate these interactions. Additionally, the project aims to determine whether full-length NS1 influences prothrombin activation and thrombin catalytic activity, as well as identify the NS1 domain responsible for inhibiting fII activation. The potential impact of prothrombin and thrombin on the functional oligomeric state of NS1, affecting its conformation and function, will also be assessed. To achieve these objectives, advanced biophysical, biochemical, and structural techniques will be employed. Overall, this proposal seeks to provide molecular and structural insights into how NS1 influences blood coagulation, contributing to the severe symptoms observed in dengue hemorrhagic fever.