title: HIV-1 adapts to a retrocyclin with cationic amino acid substitutions that reduce fusion efficiency of gp41.
abstract: Retrocyclin (RC)-101 is a cationic theta-defensin that inhibits HIV-1 entry. Passaging HIV-1(BAL) under selective pressure by this cyclic minidefensin resulted in only a 5- to 10-fold decrease in viral susceptibility to RC-101. Emergent viral isolates had three amino acid substitutions in their envelope glycoprotein. One was in a CD4-binding region of gp120, and the others were in the heptad repeat (HR) domains of gp41 (HR1 and HR2). Each mutation replaced an electroneutral or electronegative residue with one that was positively charged. These mutations were evaluated either alone or in combination in a single-round viral entry assay. Although the mutation in gp120 did not affect viral entry, the mutation in HR1 of gp41 conferred relative resistance to RC-101. Interestingly, the envelope with the HR2 mutation was less efficient and became codependent on the presence of RC-101 for entry. The adaptive response of HIV-1 to this cationic host defense peptide resembles the responses of bacteria that modulate their surface or membrane charge to evade analogous host defense peptides. These findings also suggest that interactions between theta-defensins and gp41 may contribute to the ability of these cyclic minidefensins to prevent HIV-1 entry into target cells.
authors.affiliation: Department of Molecular Biology and Microbiology, Burnett College of Biomedical Sciences, University of Central Florida, FL 32816, USA. acole@mail.ucf.edu
authors.forename: Amy L
authors.initials: AL
authors.lastname: Cole
authors.forename: Otto O
authors.initials: OO
authors.lastname: Yang
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Warren
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Waring
authors.forename: Robert I
authors.initials: RI
authors.lastname: Lehrer
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Cole
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution / Q000235:genetics; D019380:Anti-HIV Agents / Q000378:metabolism / Q000494:pharmacology; D002460:Cell Line; D023082:Defensins / Q000378:metabolism / Q000502:physiology*; D015536:Down-Regulation / Q000235:genetics; D024882:Drug Resistance, Viral / Q000235:genetics; D015700:HIV Envelope Protein gp41 / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008561:Membrane Fusion / Q000235:genetics; D008969:Molecular Sequence Data; D014760:Viral Fusion Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication / Q000187:drug effects / Q000235:genetics
chemical_list: D019380:Anti-HIV Agents; D023082:Defensins; D015700:HIV Envelope Protein gp41; D014760:Viral Fusion Proteins; C450142:theta-defensin