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Updated: Aug 5, 2025
Early Viral Entry Assays for the Identification and Evaluation of Antiviral Compounds
Published on: October 29, 2015
The Antiviral Compound PSP Inhibits HIV-1 Entry via PKR-Dependent Activation in Monocytic Cells
Eduardo Alvarez-Rivera1, Madeline Rodríguez-Valentín2, Nawal M Boukli1
1Biomedical Proteomics Facility, Department of Microbiology and Immunology, Universidad Central del Caribe School of Medicine, Bayamόn, PR 00960, USA.
Abstract:
Actin depolymerization factor (ADF) cofilin-1 is a key cytoskeleton component that serves to lessen cortical actin. HIV-1 manipulates cofilin-1 regulation as a pre- and post-entry requisite. Disruption of ADF signaling is associated with denial of entry. The unfolded protein response (UPR) marker Inositol-Requiring Enzyme-1α (IRE1α) and interferon-induced protein (IFN-IP) double-stranded RNA- activated protein kinase (PKR) are reported to overlap with actin components. In our published findings, Coriolus versicolor bioactive extract polysaccharide peptide (PSP) has demonstrated anti-HIV replicative properties in THP1 monocytic cells. However, its involvement towards viral infectivity has not been elucidated before. In the present study, we examined the roles of PKR and IRE1α in cofilin-1 phosphorylation and its HIV-1 restrictive roles in THP1. HIV-1 p24 antigen was measured through infected supernatant to determine PSP's restrictive potential. Quantitative proteomics was performed to analyze cytoskeletal and UPR regulators. PKR, IRE1α, and cofilin-1 biomarkers were measured through immunoblots. Validation of key proteome markers was done through RT-qPCR. PKR/IRE1α inhibitors were used to validate viral entry and cofilin-1 phosphorylation through Western blots. Our findings show that PSP treatment before infection leads to an overall lower infectivity. Additionally, PKR and IRE1α show to be key regulators in cofilin-1 phosphorylation and viral restriction.
Insights
Polysaccharide peptide (PSP) from Coriolus versicolor inhibits HIV-1 entry by regulating cofilin-1 phosphorylation. This study reveals PSP
Area of Science:
- Cell Biology
- Virology
- Immunology
Background:
- Actin depolymerization factor (ADF) cofilin-1 is crucial for cytoskeleton dynamics and is manipulated by HIV-1.
- The unfolded protein response (UPR) markers Inositol-Requiring Enzyme-1α (IRE1α) and protein kinase R (PKR) are linked to actin regulation.
- Previous research showed polysaccharide peptide (PSP) from Coriolus versicolor has anti-HIV properties in THP1 cells.
Purpose of the Study:
- To investigate the role of PKR and IRE1α in cofilin-1 phosphorylation and HIV-1 restriction by PSP in THP1 cells.
- To elucidate the mechanism by which PSP inhibits viral infectivity.
Main Methods:
- Quantitative proteomics to analyze cytoskeletal and UPR regulators.
- Measurement of HIV-1 p24 antigen in cell supernatant to assess PSP's antiviral potential.
- Immunoblotting and RT-qPCR for biomarker validation (PKR, IRE1α, cofilin-1).
- Use of PKR/IRE1α inhibitors to confirm their role in viral entry and cofilin-1 phosphorylation.
Main Results:
- PSP treatment prior to HIV-1 infection significantly reduced viral infectivity.
- PKR and IRE1α were identified as key regulators of cofilin-1 phosphorylation.
- PSP treatment modulated cofilin-1 phosphorylation, contributing to viral restriction.
Conclusions:
- PSP exhibits anti-HIV-1 activity by influencing cofilin-1 phosphorylation through PKR and IRE1α pathways.
- PKR and IRE1α are critical mediators of cofilin-1 phosphorylation and HIV-1 restriction.
- PSP represents a potential therapeutic agent for HIV-1 infection by targeting host cell factors.
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