Genetic variation in Trex1 affects HIV-1 disease progression

Three prime repair exonuclease 1 (TREX1) plays a pivotal role in HIV-1 infection. In-vitro studies have shown that TREX1 degrades excess HIV-1 DNA, thereby shielding HIV-1 from recognition by innate immune receptors and preventing a type 1 interferon response. To determine whether TREX1 plays a role in HIV-1 pathogenesis, we analyzed whether genetic variation in Trex1 is associated with the clinical course of HIV-1 infection. Two tagging single nucleotide polymorphisms (SNPs) in Trex1 were genotyped in a cohort of 304 HIV-1-infected MSM and a cohort of 66 high-risk seronegative individuals. Kaplan-Meier and Cox regression survival analyses were used to analyze the effect of the SNPs on HIV-1 disease progression. In-vitro HIV-1 infection assays and Trex1 mRNA analysis were performed in peripheral blood mononuclear cells (PBMCs) obtained from donors that were genotyped for the tag SNP in Trex1. We observed that the minor allele of SNP rs3135941 in Trex1 is associated with faster HIV-1 disease progression. This association was independent of the CCR5-Δ32 genotype and human leukocyte antigen alleles that were previously found to be predictive of disease progression. In addition, we observed an increased HIV-1 replication in PBMC positive for the minor allele of SNP rs3135941. Our data emphasize the important role of TREX1 in HIV-1 pathogenesis. The association of SNP rs3135941 with accelerated disease progression that we observed might be explained by the increased HIV-1 replication observed in PBMC positive for the minor allele of the SN

Mutations in CypA Binding Region of HIV-1 Capsid Affect Capsid Stability and Viral Replication in Primary Macrophages

Mutations in the cyclophilin A (CypA) binding region in the HIV-1 capsid affect their dependency on the known HIV-1 cofactor CypA and allow escape from the HIV-1 restriction factor Trim5α in human and simian cells. Here we study the effect of these mutations in the CypA binding region of capsid on cofactor binding, capsid destabilization, and viral replication in primary cells. We showed that the viral capsid with mutations in the CypA binding region (CypA-BR) interacted efficiently with CypA, but had an increased stability upon infection as compared to the wild-type capsid. Interestingly, the wild-type virus was able to infect monocyte-derived macrophages (MDM) more efficiently as compared to the CypA-BR mutant variant. The lower infectivity of the CypA-BR mutant virus in MDM was associated with lower levels of reverse transcription products. Similar to the wild-type virus, the CypA-BR mutant variant was unable to induce a strong innate response in primary macrophages. These data demonstrate that mutations in the CypA binding site of the capsid resulted in higher capsid stability and hampered infectivity in macrophage

The evolution of human immunodeficiency virus type-1 (HIV-1) envelope molecular properties and coreceptor use at all stages of infection in an HIV-1 donor-recipient pair

To trace the evolutionary patterns underlying evolution of coreceptor use within a host, we studied an HIV-1 transmission pair involving a donor who exclusively harbored CCR5-using (R5) variants throughout his entire disease course and a recipient who developed CXCR4-using variants. Over time, R5 variants in the donor optimized coreceptor use, which was associated with an increased number of potential N-linked glycosylation sites (PNGS) and elevated V3 charge in the viral envelope. Interestingly, R5 variants that were transmitted to the recipient preserved the viral characteristics of this late stage genotype and phenotype. Following a selective sweep, CXCR4-using variants subsequently emerged in the recipient coinciding with a further increase in the number of PNGS and V3 charge in the envelope of R5 viruses. Although described in a single transmission pair, the transmission and subsequent persistence of R5 variants with late stage characteristics demonstrate the potential for coreceptor use adaptation at the population level. (C) 2011 Elsevier Inc. All rights reserve

The evolution of human immunodeficiency virus type-1 (HIV-1) envelope molecular properties and coreceptor use at all stages of infection in an HIV-1 donor-recipient pair

To trace the evolutionary patterns underlying evolution of coreceptor use within a host, we studied an HIV-1 transmission pair involving a donor who exclusively harbored CCR5-using (R5) variants throughout his entire disease course and a recipient who developed CXCR4-using variants. Over time, R5 variants in the donor optimized coreceptor use, which was associated with an increased number of potential N-linked glycosylation sites (PNGS) and elevated V3 charge in the viral envelope. Interestingly, R5 variants that were transmitted to the recipient preserved the viral characteristics of this late stage genotype and phenotype. Following a selective sweep, CXCR4-using variants subsequently emerged in the recipient coinciding with a further increase in the number of PNGS and V3 charge in the envelope of R5 viruses. Although described in a single transmission pair, the transmission and subsequent persistence of R5 variants with late stage characteristics demonstrate the potential for coreceptor use adaptation at the population level.status: publishe

Receptor usage dictates HIV-1 restriction by human TRIM5α in dendritic cell subsets

The most prevalent route of HIV-1 infection is across mucosal tissues after sexual contact. Langerhans cells (LCs) belong to the subset of dendritic cells (DCs) that line the mucosal epithelia of vagina and foreskin and have the ability to sense and induce immunity to invading pathogens. Anatomical and functional characteristics make LCs one of the primary targets of HIV-1 infection. Notably, LCs form a protective barrier against HIV-1 infection and transmission. LCs restrict HIV-1 infection through the capture of HIV-1 by the C-type lectin receptor Langerin and subsequent internalization into Birbeck granules. However, the underlying molecular mechanism of HIV-1 restriction in LCs remains unknown. Here we show that human E3-ubiquitin ligase tri-partite-containing motif 5α (TRIM5α) potently restricts HIV-1 infection of LCs but not of subepithelial DC-SIGN(+) DCs. HIV-1 restriction by TRIM5α was thus far considered to be reserved to non-human primate TRIM5α orthologues, but our data strongly suggest that human TRIM5α is a cell-specific restriction factor dependent on C-type lectin receptor function. Our findings highlight the importance of HIV-1 binding to Langerin for the routeing of HIV-1 into the human TRIM5α-mediated restriction pathway. TRIM5α mediates the assembly of an autophagy-activating scaffold to Langerin, which targets HIV-1 for autophagic degradation and prevents infection of LCs. By contrast, HIV-1 binding to DC-SIGN(+) DCs leads to disassociation of TRIM5α from DC-SIGN, which abrogates TRIM5α restriction. Thus, our data strongly suggest that restriction by human TRIM5α is controlled by C-type-lectin-receptor-dependent uptake of HIV-1, dictating protection or infection of human DC subsets. Therapeutic interventions that incorporate C-type lectin receptors and autophagy-targeting strategies could thus provide cell-mediated resistance to HIV-1 in human