Dengue Virus (DENV-2)-Induced Epididymitis in Mice: Overview of the Inflammatory Profile and Immune Cell Recruitment.

• Grant number: 25/04157-9
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: November 30, 2028
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Erick José Ramo da Silva
• Grantee: Isabela Andrade de Camargo
• Host Institution: Instituto de Biociências (IBB). Universidade Estadual Paulista (UNESP). Campus de Botucatu. Botucatu , SP, Brazil
• Associated research grant: 21/06718-7 - Translational studies on the sperm-binding protein EPPIN as a male contraceptive drug target, AP.JP2

Abstract

Dengue virus (DENV) is one of the flaviviruses with the greatest impact on global public health, with four distinct serotypes and widespread distribution in tropical and subtropical regions. In 2024, Brazil recorded the largest dengue epidemic in its history. The disease can be asymptomatic or induce symptoms ranging from fever, chills, headache, and myalgia to hemorrhagic manifestations and plasma leakage, in its most severe forms. It is transmitted mainly through the bite of mosquitoes of the Aedes genus, but other routes, such as blood transfusion and organ transplantation, have also been documented. Evidence indicates the presence of DENV in semen, suggesting its ability to infect and colonize the male reproductive system and the possibility of sexual transmission. The epididymis can be affected by viral infections, leading to inflammatory conditions, known as epididymitis, compromising male reproductive health. Studies by our group have demonstrated that DENV-2 non-structural protein 1 (NS1) induces acute inflammation in the epididymis of mice, in a TLR4-dependent manner. Using a neuroadapted intracerebral infection model of DENV-2 New Guinea strain (NGC) in mice, we also demonstrated the activation of an immune response in the epididymis, with increased expression of inflammatory mediator transcripts, such as interferon beta 1 (Ifnb1) and interferon gamma (Ifng). Considering that the reproductive-age population is among the groups most exposed to the risk of infection, it is essential to investigate the consequences of the disease in the male reproductive system. In the present project, we will evaluate the profile of the immune response of the epididymis after infection by DENV-2 New Guinea strain (NGC), as well as the possible protective effects of immunization with the pcTPANS1 DNA vaccine. To this end, mice will be infected with DENV-2 intracerebrally or intravenously and, at specific times post-infection, the epididymis will be processed for RT-qPCR and Multiplex panel assays for viral quantification and cytokine and chemokine expression (mRNA and protein), histopathological analyses for quantifying cellular damage, flow cytometry for characterization of the immune cell population and immunofluorescence for identification of the distribution of viral proteins. In parallel, groups immunized with the pcTPANS1 DNA vaccine will be evaluated for efficacy in reducing viral load and inflammation in the epididymis. We hope to advance the knowledge of the pathophysiological mechanisms of viral epididymitis induced by DENV-2 and its impact on the male reproductive system, in addition to supporting new preventive and therapeutic strategies in order to mitigate the effects of viral infection and preserve male reproductive health.