Influence of membrane fluidity on human immunodeficiency virus type 1 entry

Area of Science:

• Virology
• Cell Biology
• Biophysics

Background:

• Human immunodeficiency virus type 1 (HIV-1) entry into host cells is a complex process involving viral envelope proteins and host cell membranes.
• The precise biophysical mechanisms governing HIV-1 fusion and entry remain an active area of research.
• Membrane fluidity is a critical biophysical property influencing membrane-mediated events, including viral fusion.

Purpose of the Study:

• To investigate the role of plasma membrane and viral envelope fluidity in HIV-1 penetration.
• To determine the quantitative relationship between membrane fluidity and HIV-1 infectivity.
• To explore how factors affecting membrane fluidity influence HIV-1 entry dynamics.

Main Methods:

• Treatment of cells and virus with fluidity-modulating agents.
• Quantification of HIV-1 infectivity following fluidity modulation.
• Assessment of the impact of temperature and xylocaine on HIV-1 infectivity.
• Inhibition studies using anti-CXCR4 peptide.

Main Results:

• HIV-1 infectivity demonstrated a strong dependence on membrane fluidity.
• A 5% decrease in fluidity suppressed infectivity by 56%, while a 5% increase augmented it 2.4-fold.
• Elevated temperature (40°C) and xylocaine treatment enhanced infectivity by 2.6- and 1.5-fold, respectively.
• These enhancements were sensitive to anti-CXCR4 peptide, suggesting accelerated multiple-site binding.

Conclusions:

• Membrane fluidity is essential for the formation of the fusion-pore during HIV-1 entry.
• Both plasma membrane and viral envelope fluidity are required for complete HIV-1 penetration.
• Fluidity modulation offers a potential target for understanding and potentially controlling HIV-1 infection.