Piperidine CD4-Mimetic Compounds Expose Vulnerable Env Epitopes Sensitizing HIV-1-Infected Cells to ADCC

Area of Science:

• Virology
• Immunology
• Medicinal Chemistry

Background:

• HIV-1 accessory proteins Nef and Vpu reduce CD4 levels, shielding infected cells from antibody-dependent cellular cytotoxicity (ADCC).
• Small-molecule CD4 mimetics (CD4mc) expose CD4-induced (CD4i) epitopes, sensitizing HIV-1-infected cells to ADCC.
• Non-neutralizing antibodies in HIV-1 patient plasma recognize these CD4i epitopes.

Purpose of the Study:

• To characterize a new family of piperidine-based CD4mc derivatives.
• To develop analogs with improved activity against difficult-to-neutralize HIV-1 variants.
• To investigate the potential of these molecules in eliminating HIV-1-infected cells.

Main Methods:

• Structure-based drug design utilizing piperidine scaffolds.
• Synthesis and characterization of novel CD4mc analogs.
• Assays to evaluate inhibition of tier-2 HIV-1 infection and ADCC sensitization.

Main Results:

• New piperidine-based CD4mc derivatives were developed, engaging the gp120 Phe43 cavity and targeting conserved Asp368.
• Analogs demonstrated improved activity in inhibiting tier-2 HIV-1 infection.
• These molecules effectively sensitized HIV-1-infected cells to ADCC mediated by HIV+ plasma.
• A key H-bond interaction with Asp368 was identified, expanding the chemical space for anti-Env molecules.

Conclusions:

• The novel CD4mc derivatives show significant potential for HIV-1 therapy.
• These molecules enhance ADCC by exposing CD4i epitopes, facilitating infected cell elimination.
• The identified structural features provide a foundation for developing broader-spectrum anti-Env therapeutics.