Effect of cell polarization on hepatitis C virus entry

Area of Science:

• Virology
• Cell Biology
• Hepatology

Background:

• Hepatocytes are the primary reservoir for Hepatitis C virus (HCV) replication.
• HCV entry requires host cell factors including CD81, scavenger receptor BI (SR-BI), and claudin 1 (CLDN1).
• The role of tight junctions (TJs) and cell polarization in HCV entry is under investigation.

Purpose of the Study:

• To investigate the impact of tight junction (TJ) formation and cell polarization on Hepatitis C virus (HCV) entry.
• To analyze the expression and localization of HCV entry factors in polarized Caco-2 cells.
• To determine the role of TJs as a barrier in HCV entry.

Main Methods:

• Utilized the polarized colorectal adenocarcinoma Caco-2 cell line expressing HCV entry receptors.
• Assessed viral receptor expression and localization upon cell polarization.
• Performed HCV pseudoparticle and recombinant E1E2 glycoprotein infection assays.
• Evaluated the effect of TJ disruption on HCV entry.

Main Results:

• Polarized Caco-2 cells exhibited increased viral receptor expression and CLDN1 relocalization to cell-cell junctions.
• HCV entry and pseudoparticle infection occurred predominantly at the apical surface of polarized cells.
• Disruption of TJs significantly enhanced HCV entry, indicating a barrier function.
• HCV entry was glycoprotein-dependent and neutralized by anti-E2 antibodies.

Conclusions:

• Tight junctions (TJs) play a crucial role in regulating Hepatitis C virus (HCV) entry.
• TJs form a physical barrier that restricts viral access to receptors on lateral and basolateral domains.
• Cell polarization and TJ integrity are key factors influencing HCV infection pathways.