RESUMO
Antimicrobial peptides are effectors of innate immunity, providing their hosts with rapid non-specific defence against parasitic invaders. In this report, the effects are assessed of two well-characterized antimicrobial amphipathic peptides (melittin and cecropin) on human immunodeficiency virus 1 (HIV-1) replication and gene expression in acutely infected cells at subtoxic concentrations. Production of infectious, cell-free virus was inhibited in a dose-dependent manner, with ID50 values in the range 0.9-1.5 microM for melittin and 2-3 microM for cecropin. Analysis of the effect of melittin on cell-associated virus production revealed decreased levels of Gag antigen and HIV-1 mRNAs. Transient transfection assays with HIV long terminal repeat (LTR)-driven reporter gene plasmids indicated that melittin has a direct suppressive effect on activity of the HIV LTR. HIV LTR activity was also reduced in human cells stably transfected with retroviral expression plasmids for the melittin or cecropin gene. It is concluded that antimicrobial peptides such as melittin and cecropin are capable of inhibiting cell-associated production of HIV-1 by suppressing HIV-1 gene expression.
Assuntos
Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos , HIV-1/efeitos dos fármacos , Meliteno/farmacologia , Peptídeos/farmacologia , Sequência de Bases , Linhagem Celular , Primers do DNA/genética , Expressão Gênica/efeitos dos fármacos , Genes Virais/efeitos dos fármacos , Repetição Terminal Longa de HIV/efeitos dos fármacos , HIV-1/genética , HIV-1/fisiologia , Humanos , Meliteno/genética , Peptídeos/genética , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , RNA Viral/biossíntese , Transfecção , Proteínas Virais/biossíntese , Replicação Viral/efeitos dos fármacos , Replicação Viral/genéticaRESUMO
Bryodin, a single-chain ribosome-inactivating protein (RIP) isolated from Bryonia cretica ssp dioica (cucurbitaceae), was found to selectively inhibit the growth of persistently HIV-1-infected T lymphoma cells (KE37/1) and human lung fibroblast when used in concentrations from 2-20 micrograms/ml. Uninfected KE37/1 cells remained unaffected at the same doses of bryodin. In addition, bryodin reduced HIV production in the surviving infected cells. Two isoforms of bryodin were purified by dye ligand chromatography. Both isoforms exerted the growth-inhibiting influence and reduced HIV production. Trichosanthin, another member of the RIP family, had similar inhibitory effects on the growth of HIV-1 infected cells and on HIV-1 production. Bryodin and trichosanthin were effective in about the same dose range. No selective effects for HIV-infected cells were observed with the RIPs gelonin and ricin.
Assuntos
HIV-1/efeitos dos fármacos , HIV-1/crescimento & desenvolvimento , Proteínas de Plantas/farmacologia , Ribossomos/efeitos dos fármacos , Toxinas Biológicas , Replicação Viral/efeitos dos fármacos , Células Cultivadas , Eletroforese em Gel de Poliacrilamida , Fibroblastos/efeitos dos fármacos , Humanos , Inibidores da Síntese de Proteínas/farmacologia , Proteínas Inativadoras de Ribossomos Tipo 1 , Ricina/farmacologia , Tricosantina/farmacologiaRESUMO
The effects of several amphipathic peptides on HIV-1 production in persistently infected cells are described. Melittin, a 26 amino acid alpha-helical amphipathic peptide, reduces HIV-1 production dose-dependently, whereas other amphipathic peptides do not. Six melittin derivatives which retain the alpha-helical portion have similar effects as melittin. The reduction of viral infectivity is not due to an effect of melittin on the virus particles but to an intracellular action of the peptide, which is readily taken up into cells, as shown by quantitative ELISA. Western blots of cells from melittin-treated cultures suggest that the processing of the gag/pol precursor is impaired.
