Ebola virus enters host cells by macropinocytosis and clathrin-mediated endocytosis

Area of Science:

• Virology
• Cell Biology
• Pathogenesis

Background:

• Virus entry into host cells is critical for infection and disease severity.
• Understanding viral entry mechanisms is essential for developing effective antiviral therapies.

Purpose of the Study:

• To elucidate the entry pathways utilized by Ebola virus-like particles (EBOV-VLPs).
• To investigate the roles of macropinocytosis and clathrin-mediated endocytosis in EBOV-VLP cellular entry.

Main Methods:

• EBOV-VLPs were applied to host cells to observe cellular uptake and associated mechanisms.
• Macropinocytosis was assessed by monitoring actin-driven ruffling and FITC-dextran uptake.
• Inhibitors of actin polymerization, Na(+)/H(+)-exchanger, and PI3-kinase were used to block entry.
• Clathrin-mediated endocytosis was investigated through colocalization with clathrin heavy chain (CHC) and the use of CHC siRNA and a dominant-negative dynamin II mutant.

Main Results:

• EBOV-VLPs primarily entered cells via macropinocytosis, evidenced by induced ruffling and enhanced FITC-dextran uptake.
• Inhibitors targeting macropinocytosis pathways significantly reduced EBOV-VLP entry.
• A subset of EBOV-VLPs utilized clathrin-mediated endocytosis, confirmed by colocalization with CHC and reduced uptake upon CHC depletion or dynamin II inhibition.
• No evidence supported caveolae-mediated entry of EBOV-VLPs.

Conclusions:

• Macropinocytosis is the predominant entry route for EBOV particles.
• Clathrin-dependent endocytosis serves as an alternative pathway for EBOV particle entry.
• Ebola virus entry mechanisms may vary based on cell type and particle characteristics, influencing pathogenicity.