[F32] Entry Determinants for Understanding Parechovirus Neurotropism

Description

Project Summary/Abstract Parechovirus A3 (PeV-A3) is an underrecognized picornavirus that causes severe disease in infants, including meningitis, encephalitis, and sepsis-like illness. Although PeV-A1 and PeV-A3 are the most common genotypes circulating in the United States, only PeV-A3 displays consistent neurovirulence in young infants. This disparity suggests that the two viruses engage distinct host entry factors or exploit unique tissue environments to facilitate central nervous system (CNS) infection. Because no targeted therapies or vaccines exist, defining the mechanisms that enable PeV-A3 to infect CNS tissues is essential for improving surveillance and therapeutic strategies. The overall goal of this project is to define viral and host determinants that drive PeV-A3 entry and neurotropism. The central hypothesis is that PeV-A3 uses distinct entry factors compared to PeV-A1 and that its ability to infect choroid plexus (ChP) tissue contributes to its presence in cerebrospinal fluid (CSF) and its association with meningitis. Preliminary findings from an unbiased CRISPR-Cas9 knockout screen identified a novel cell surface protein as a candidate entry factor uniquely required for PeV-A3 infection, supporting the idea that divergent receptor usage contributes to genotype-specific disease. Specific Aim 1 will investigate this host protein as a potential entry factor for PeV-A3. We will test the hypothesis that PeV-A3 utilizes this protein for attachment and entry using three complementary approaches: (1) quantify attachment to non-permissive CHO cells engineered to express this protein; (2) receptor neutralization assay using soluble recombinant protein; and (3) ELISA and binding assays to determine level of virion attachment to our identified protein. These studies will define whether our identified protein directly mediates PeV-A3 attachment and identify key structural elements required for infection. Specific Aim 2 will characterize infection dynamics and immune responses to PeV-A1 and PeV-A3 in human ChP organoids. We hypothesize that PeV-A3 uniquely infects ChP cells and elicits strong proinflammatory signals that contribute to meningitis. Using a long-term ChP organoid model, a New Approach Methodology (NAM) that reduces reliance on animal models, we will compare genotype-specific infection patterns, viral release into CSF, and induction of antiviral cytokines. Viral antigen localization, genome quantification, and multiplex immune profiling will define how each genotype interacts with ChP tissue and triggers distinct innate responses. Completion of these studies will identify mechanistic differences in receptor usage, tissue tropism, and immune activation that explain why PeV-A3 causes more severe neurologic disease in infants. This fellowship leverages NAM-based human organoid models and interdisciplinary training in viral entry mechanisms and host-pathogen interactions under guidance of two mentors with complementary expertise. Ultim Istituzione: UNIV OF NORTH CAROLINA CHAPEL HILL PI: Lorellin Durnell Progetto: 1F32AI203003-01

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Source

Source: reporter.nih.gov