cytidylyl-3--5--guanosine and HIV-Infections

The clinical course of HIV-1 varies greatly among infected individuals. Despite extensive research, virus factors associated with slow-progression remain poorly understood. Identification of unique HIV-1 genomic signatures linked to slow-progression remains elusive. We investigated CpG dinucleotide content in HIV-1 envelope gene as a potential virus factor in disease progression. We analysed 1808 HIV-1 envelope gene sequences from three independent longitudinal studies; this included 1280 sequences from twelve typical-progressors and 528 sequences from six slow-progressors. Relative abundance of CpG dinucleotides and relative synonymous codon usage (RSCU) for CpG-containing codons among HIV-1 envelope gene sequences from typical-progressors and slow-progressors were analysed. HIV-1 envelope gene sequences from slow-progressors have high-CpG dinucleotide content and increased number of CpG-containing codons as compared to typical-progressors. Our findings suggest that observed differences in CpG-content between typical-progressors and slow-progressors is not explained by differences in the mononucleotide content. Our results also highlight that the high-CpG content in HIV-1 envelope gene from slow-progressors is observed immediately after seroconversion. Thus CpG dinucleotide content of HIV-1 envelope gene is a potential virus-related factor that is linked to disease progression. The CpG dinucleotide content of HIV-1 envelope gene may help predict HIV-1 disease progression at early stages after seroconversion.

Topics: Base Composition; Codon; Dinucleoside Phosphates; Disease Progression; Genes, env; HIV Infections; HIV Seropositivity; HIV-1; Humans; Prognosis; Sequence Analysis, DNA

Efforts to cure HIV-1 infections aim at eliminating proviral DNA. Integrated DNA from various viruses often becomes methylated de novo and transcriptionally inactivated. We therefore investigated CpG methylation profiles of 55 of 94 CpG's (58.5%) in HIV-1 proviral genomes including ten CpG's in each LTR and additional CpG's in portions of gag, env, nef, rev, and tat genes. We analyzed 33 DNA samples from PBMC's of 23 subjects representing a broad spectrum of HIV-1 disease. In 22 of 23 HIV-1-infected individuals, there were only unmethylated CpG's regardless of infection status. In one long term nonprogressor, however, methylation of proviral DNA varied between 0 and 75% over an 11-year period although the CD4+ counts remained stable. Hence levels of proviral DNA methylation can fluctuate. The preponderance of unmethylated CpG's suggests that proviral methylation is not a major factor in regulating HIV-1 proviral activity in PBMC's. Unmethylated CpG's may play a role in HIV-1 immunopathogenesis.

Topics: Adult; Cells, Cultured; Dinucleoside Phosphates; DNA Methylation; Epigenesis, Genetic; Female; Genome, Viral; HIV Infections; HIV-1; Humans; Leukocytes, Mononuclear; Male; Proviruses; Young Adult

Topical microbicides represent a promising new approach to preventing HIV and other sexually transmitted infections. TLR agonists are ideal candidates for microbicides, as they trigger a multitude of antiviral genes effective against a broad range of viruses. Although vaginal application of CpG oligodeoxynucleotides (ODNs) and poly I:C has been shown to protect mice from genital herpes infection, the mechanism by which these agents provide protection remains unclear. Here, we show that plasmacytoid DCs (pDCs) are required for CpG ODN-mediated protection against lethal vaginal challenge with herpes simplex virus type 2 (HSV-2). Moreover, we demonstrate that cells of both the hematopoietic and stromal compartments must respond to CpG ODN via TLR9 and to type I IFNs through IFN-alphabeta receptor (IFN-alphabetaR) for protection. Thus, crosstalk between pDCs and vaginal stromal cells provides for optimal microbicide efficacy. Our results imply that temporally and spatially controlled targeting of CpG ODN to pDCs and epithelial cells can potentially maximize their effectiveness as microbicides while minimizing the associated inflammatory responses.

Topics: Animals; Anti-Infective Agents; Antiviral Agents; Base Sequence; Dendritic Cells; Dinucleoside Phosphates; Female; HIV Infections; Mice; Mice, Inbred C57BL; Mice, Inbred Strains; Oligodeoxyribonucleotides; Plasma Cells; Sexually Transmitted Diseases; Vagina

Intra-anal malignancies disproportionately affect individuals who engage in anal intercourse because of infection with human papillomaviruses (HPVs), with an increased risk attributed to infection with HIV because of a declining immunity against HPVs. Long-term persistence of HPVs suggests yet other mechanisms that determine the clinical outcome, however. Because methylation of HPV DNA represses oncogene expression in cervical samples, we investigated whether this mechanism also occurs in HIV-positive men and studied the methylation of CpG dinucleotides overlapping with the HPV-16 enhancer and promoter in 16 anal samples. Similar to cervical infections, the average methylation frequency was 12.3%, with heterogeneities between clones from different and the same samples. In low-grade anal intraepithelial neoplasia (AIN), methylation was high in CpGs overlapping the viral enhancer but rare in promoter positions, whereas methylation was high in promoter regions in high-grade AIN, especially in samples with a high load of viral genomes. The viral replication origin was never methylated. We also detected de novo methylation at methylated (me) CpA, meCpT, and meCpC dinucleotides. Our study expands the observation and mapping of HPV DNA methylation to anal infections and the HIV-positive patient population. As observed at the cervix, DNA methylation may force HPVs into latency with functional replication but repressed transcription. Escape from this repression is a prerequisite for neoplastic progression; however, methylation resumes because of chromosomal integration of HPV genomes but spares some HPV genomes in each cell that maintain the transformed phenotype. DNA methylation, taken together with virus load, may be useful to diagnose the emergence of a population of tumor cells.

Topics: Anal Canal; Base Sequence; Biopsy; Dinucleoside Phosphates; DNA Methylation; DNA Primers; DNA, Viral; Enhancer Elements, Genetic; Genome, Viral; HIV Infections; Homosexuality, Male; Humans; Intestinal Mucosa; Male; Papillomaviridae; Polymerase Chain Reaction; Virus Latency; Virus Replication