Risk factors of oncogenic HPV infection in HIV-positive men with anal condyloma acuminata in Shenzhen, Southeast China: a retrospective cohort study.

Background: Human immunodeficiency virus (HIV)-positive patients with anal condyloma acuminata (CA) present an increased risk of anal cancer progression associated with oncogenic human papillomavirus (HPV) infection. It is essential to explore determinants of anal infection by oncogenic HPV among HIV-positive patients with CA. Methods: A retrospective cohort study was performed in HIV-positive patients with CA between January 2019 to October 2021 in Shenzhen, Southeast China. Exfoliated cells were collected from CA lesions and the anal canal of HPV genotypes detected by fluorescence PCR. Unconditional logistic regression analysis was used to probe associations of independent variables with oncogenic HPV infection. Results: Among HIV-positive patients with CA, the most prevalent oncogenic genotypes were HPV52 (29.43%), HPV16 (28.93%), HPV59 (19.20%), and HPV18 (15.96%). Risk of oncogenic HPV infection increased with age at enrollment (COR: 1.04, 95% CI: 1.01-1.07, p = 0.022). In the multivariable analysis, age ≥ 35 years (AOR: 2.56, 95% CI: 1.20-5.70, p = 0.02) and history of syphilis (AOR: 3.46, 95% CI: 1.90-6.79, p < 0.01) were independent risk factors statistically associated with oncogenic HPV infection. History of syphilis (AOR: 1.72, 95% CI: 1.08-2.73, p < 0.02) was also an independent risk factor statistically associated with HPV16 or HPV18 infection. Conclusion: In clinical practice, HIV-positive CA patients aged ≥35 years or with a history of syphilis should carry out HR-HPV testing and even anal cancer-related examinations to prevent the occurrence of anal cancer.

The HLA-B*57:01 allele corresponds to a very large MHC haploblock likely explaining its massive effect for HIV-1 elite control.

Introduction: We have reanalyzed the genomic data of the International Collaboration for the Genomics of HIV (ICGH), centering on HIV-1 Elite Controllers. Methods: We performed a genome-wide Association Study comparing 543 HIV Elite Controllers with 3,272 uninfected controls of European descent. Using the latest database for imputation, we analyzed 35,552 Single Nucleotide Polymorphisms (SNPs) within the Major Histocompatibility Complex (MHC) region. Results: Our analysis identified 2,626 SNPs significantly associated (p<5. 10-8) with elite control of HIV-1 infection, including well-established MHC signals such as the rs2395029-G allele which tags HLA-B*57:01. A thorough investigation of SNPs in linkage disequilibrium with rs2395029 revealed an extensive haploblock spanning 1.9 megabases in the MHC region tagging HLA-B*57:01, comprising 379 SNP alleles impacting 72 genes. This haploblock contains damaging variations in proteins like NOTCH4 and DXO and is also associated with a strong differential pattern of expression of multiple MHC genes such as HLA-B, MICB, and ZBTB12. The study was expanded to include two cohorts of seropositive African-American individuals, where a haploblock tagging the HLA-B*57:03 allele was similarly associated with control of viral load. The mRNA expression profile of this haploblock in African Americans closely mirrored that in the European cohort. Discussion: These findings suggest that additional molecular mechanisms beyond the conventional antigen-presenting role of class I HLA molecules may contribute to the observed influence of HLA-B*57:01/B*57:03 alleles on HIV-1 elite control. Overall, this study has uncovered a large haploblock associated with HLA-B*57 alleles, providing novel insights into their massive effect on HIV-1 elite control.

HIV-1 Remission: Accelerating the Path to Permanent HIV-1 Silencing.

Despite remarkable progress, a cure for HIV-1 infection remains elusive. Rebound competent latent and transcriptionally active reservoir cells persevere despite antiretroviral therapy and rekindle infection due to inefficient proviral silencing. We propose a novel "block-lock-stop" approach, entailing long term durable silencing of viral expression towards an irreversible transcriptionally inactive latent provirus to achieve long term antiretroviral free control of the virus. A graded transformation of remnant HIV-1 in PLWH from persistent into silent to permanently defective proviruses is proposed, emulating and accelerating the natural path that human endogenous retroviruses (HERVs) take over millions of years. This hypothesis was based on research into delineating the mechanisms of HIV-1 latency, lessons from latency reversing agents and advances of Tat inhibitors, as well as expertise in the biology of HERVs. Insights from elite controllers and the availability of advanced genome engineering technologies for the direct excision of remnant virus set the stage for a rapid path to an HIV-1 cure.

Characteristics of genotype, drug resistance, and molecular transmission network among newly diagnosed HIV-1 infections in Shenzhen, China.

The HIV-1 pandemic has persisted for four decades, and poses a major challenge to global public health. Shenzhen, a city with large number of migrant populations in China, is suffering HIV-1 epidemic. It is necessary to continuously conduct the molecular surveillance among newly diagnosed HIV-1 patients in these migrant population. In this study, plasma samples of newly diagnosed and ART-naive HIV-1 infections were collected from Shenzhen city in China. The partial genes of HIV-1 gag and pol were amplified and sequenced for the analysis of genotype, drug resistance, and molecular transmission network. Ninety-one sequences of pol gene were obtained from newly diagnosed HIV-1 infections in Shenzhen, and seven HIV-1 subtypes were revealed in this investigation. Among them, the circulating recombinant form (CRF) 07_BC was the mostly frequent subtype (53.8%, 49/91), followed by CRF01_AE (20.9%, 19/91), CRF55_01B (9.9%, 9/91), unique recombinant forms (URFs) (8.8%, 8/91), B (3.3%, 3/91), CRF59_01B (2.2%, 2/91), and CRF08_BC (1.1%, 1/91). The overall prevalence of pretreatment drug resistance (PDR) was 23.1% (21/91), and 52.38% (11/21) of the PDR was specific for the nonnucleotide reverse transcriptase inhibitors (NNRTIs). Furthermore, a total of 3091 pol gene sequences were used to generate 19 molecular transmission clusters, and then one growing cluster, a new cluster, and a cluster with growth reactivation were identified. The result revealed that more sexual partner, CRF_07BC subtype, and seven amino acid deletions in gag p6 region might be the influencing factors associated with the high risk of transmission behavior. Compared with CRF01_AE subtype, CRF07_BC subtype strains were more likely to form clusters in molecular transmission network. This suggests that long-term surveillance of the HIV-1 molecular transmission should be a critical measure to achieve a precise intervention for controlling the spread of HIV-1 in China.

HIV-1 molecular transmission network and drug resistance in Chongqing, China, among men who have sex with men (2018-2021).

BACKGROUND: Over the past few years, HIV transmission among men who have sex with men (MSM) in China has increased significantly. Chongqing, located in the southwest of China, has the highest prevalence of HIV among MSM in the country. METHODS: Blood samples were taken from 894 MSM in Chongqing who had recently been diagnosed with HIV-1 infection and had not yet started getting treatment. In order to determine the distribution of HIV-1 subtypes, transmitted drug resistance, and assessments of molecularly transmitted clusters, we sequenced the Pol genes and employed them in phylogenetic analysis. The genetic distance between molecular clusters was 1.5%. To find potential contributing factors, logistic regression analyses were performed. RESULTS: Of the 894 HIV-1 pol sequences acquired from study participants, we discovered that CRF07_BC (73.6%) and CRF01_AE (19.6%) were the two most prevalent HIV-1 genotypes in Chongqing among MSM, accounting for 93.2% of all infections. In addition, CRF08_BC (1.1%), B subtype (1.0%), CRF55_01B (3.4%), and URF/Other subtypes (1.3%) were less frequently observed. Among MSM in Chongqing, transmitted drug resistance (TDR) was reported to be present at a rate of 5.6%. 48 clusters with 600 (67.1%, 600/894) sequences were found by analysis of the molecular transmission network. The distributions of people by age, sexual orientation, syphilis, and genotype were significantly differentially related to being in clusters, according to the multivariable logistic regression model. CONCLUSION: Despite the low overall prevalence of TDR, the significance of genotypic drug resistance monitoring needs to be emphasized. CRF07_BC and CRF01_AE were the two main genotypes that created intricate molecular transmission networks. In order to prevent the expansion of molecular networks and stop the virus's spread among MSM in Chongqing, more effective HIV intervention plans should be introduced.

Genome mosaic structure of two novel HIV-1 recombinant forms (CRF01_AE/B) in men who have sex with men in Hebei, China.

BACKGROUND: Homosexual contact is the main route of human immunodeficiency virus type one (HIV-1) transmission in Cangzhou Prefecture, Hebei, China. Moreover, the number of circulating recombinant forms (CRFs) and unique recombinant forms (URFs) in this key population is ever increasing. METHODS: In this study, we identified two novel URFs (hcz0017 and hcz0045) from two men who have sex with men (MSM) based in Cangzhou Prefecture. Phylogenetic and recombinant breakpoint analyses, based on the near full-length genomes (NFLGs) of the two novel URFs, showed that they originated from a recombination between HIV-1 CRF01_AE and subtype B. RESULTS: HXB2 numbering revealed that the NFLGs of hcz0017 and hcz0045 each contained the following seven subregions: hcz0017: IB (790-1,171 nt), IICRF01_AE (1,172-2,022 nt), IIIB (2,023-4,469 nt), IVCRF01_AE (4,470-5,866 nt), VB (5,867-7,462 nt), VICRF01_AE (7,463-8,379 nt), VIIB (8,380-9,411 nt); hcz0045: ICRF01_AE (790-5,147 nt), IIB (5,148-5,614 nt), IIICRF01_AE (5,615-6,035 nt), IVB (6,036-6,241 nt), VCRF01_AE (6,242-7,325nt), VIB (7,326-8,254 nt), VIICRF01_AE (8,255-9,411 nt). Moreover, the two MSM from whom the novel URFs originated from were diagnosed as recently HIV-1-infected, suggesting that the high prevalence of HIV-1 among MSM was related to high-risk sexual activity such as unprotected anal sex and multiple sexual partners. CONCLUSIONS: Our results highlight the need to continually monitor HIV-1 diversity in Hebei and its neighboring provinces to achieve a more effective control of HIV-1 spread within the MSM community.

A modular CRISPR screen identifies individual and combination pathways contributing to HIV-1 latency.

Transcriptional silencing of latent HIV-1 proviruses entails complex and overlapping mechanisms that pose a major barrier to in vivo elimination of HIV-1. We developed a new latency CRISPR screening strategy, called Latency HIV-CRISPR which uses the packaging of guideRNA-encoding lentiviral vector genomes into the supernatant of budding virions as a direct readout of factors involved in the maintenance of HIV-1 latency. We developed a custom guideRNA library targeting epigenetic regulatory genes and paired the screen with and without a latency reversal agent-AZD5582, an activator of the non-canonical NFκB pathway-to examine a combination of mechanisms controlling HIV-1 latency. A component of the Nucleosome Acetyltransferase of H4 histone acetylation (NuA4 HAT) complex, ING3, acts in concert with AZD5582 to activate proviruses in J-Lat cell lines and in a primary CD4+ T cell model of HIV-1 latency. We found that the knockout of ING3 reduces acetylation of the H4 histone tail and BRD4 occupancy on the HIV-1 LTR. However, the combination of ING3 knockout accompanied with the activation of the non-canonical NFκB pathway via AZD5582 resulted in a dramatic increase in initiation and elongation of RNA Polymerase II on the HIV-1 provirus in a manner that is nearly unique among all cellular promoters.

Comprehensive Genetic Characterization of Four Novel HIV-1 Circulating Recombinant Forms (CRF129_56G, CRF130_A1B, CRF131_A1B, and CRF138_cpx): Insights from Molecular Epidemiology in Cyprus.

Molecular investigations of the HIV-1 pol region (2253-5250 in the HXB2 genome) were conducted on sequences obtained from 331 individuals infected with HIV-1 in Cyprus between 2017 and 2021. This study unveiled four distinct HIV-1 putative transmission clusters, encompassing 19 previously unidentified HIV-1 recombinants. These recombinants, each comprising eight, three, four, and four sequences, respectively, did not align with previously established Circulating Recombinant Forms (CRFs). To characterize these novel HIV-1 recombinants, near-full-length genome sequences were successfully obtained for 16 of the 19 recombinants (790-8795 in the HXB2 genome) using an in-house-developed RT-PCR assay. Phylogenetic analyses, employing MEGAX and Cluster-Picker, along with confirmatory neighbor-joining tree analyses of subregions, were conducted to identify distinct clusters and determine subtypes. The uniqueness of the HIV-1 recombinants was evident in their exclusive clustering within generated maximum likelihood trees. Recombination analyses highlighted the distinct chimeric nature of these recombinants, with consistent mosaic patterns observed across all sequences within each of the four putative transmission clusters. Conclusive genetic characterization identified four novel HIV-1 CRFs: CRF129_56G, CRF130_A1B, CRF131_A1B, and CRF138_cpx. CRF129_56G exhibited two recombination breakpoints and three fragments of subtypes CRF56_cpx and G. Both CRF130_A1B and CRF131_A1B featured seven recombination breakpoints and eight fragments of subtypes A1 and B. CRF138_cpx displayed five recombination breakpoints and six fragments of subtypes CRF22_01A1 and F2, along with an unclassified fragment. Additional BLAST analyses identified a Unique Recombinant Form (URF) of CRF138_cpx with three additional recombination sites, involving subtype F2, a fragment of unknown subtype origin, and CRF138_cpx. Post-identification, all putative transmission clusters remained active, with CRF130_A1B, CRF131_A1B, and CRF138_cpx clusters exhibiting further growth. Furthermore, international connections were identified through BLAST analyses, linking one sequence from the USA to the CRF130_A1B strain, and three sequences from Belgium and Cameroon to the CRF138_cpx strain. This study contributes valuable insights into the dynamic landscape of HIV-1 diversity and transmission patterns, emphasizing the need for ongoing molecular surveillance and global collaboration in tracking emerging viral variants.

HIV-1 Rev-RRE functional activity in primary isolates is highly dependent on minimal context-dependent changes in Rev.

During HIV infection, intron-containing viral mRNAs are exported from the cell nucleus to the cytoplasm to complete the replication cycle. Cellular restrictions on the export of incompletely spliced transcripts are overcome by a viral protein, Rev, and an RNA structure found in all unspliced and incompletely spliced viral mRNAs, the Rev Response Element (RRE). Primary HIV isolates display substantial variation in the sequence and functional activity of Rev proteins. We analyzed Rev from two primary isolates with disparate activity that resulted in differences in in vitro fitness of replication-competent viral constructs. The results showed that amino acid differences within the oligomerization domain, but not the arginine-rich motif or the nuclear export signal, determined the level of Rev activity. Two specific amino acid substitutions were sufficient to alter the low-activity Rev to a high-activity phenotype. Other mutations in Rev sequences had unpredictable effects on activity that differed between the two Rev backbones. The sensitivity of Rev function level to small sequence changes likely permits modulation of Rev-RRE activity during HIV infection, which may play a role in pathogenesis. The functional consequences of Rev mutations differed between primary isolates, highlighting the challenge of generalizing studies of Rev conducted using laboratory HIV strains.

Immunological Control of HIV-1 Disease Progression by Rare Protective HLA Allele.

Rare HLA alleles such as HLA-B57 are associated with slow progression to AIDS. However, the evidence for the advantage of rare protective alleles is limited, and the mechanism is still unclear. Although the prevalence of HLA-B*67:01 is only 1.2% in Japan, HLA-B*67:01-positive (HLA-B*67:01+) individuals had the lowest plasma viral load (pVL) and highest CD4 count in HIV-1 clade B-infected Japanese individuals. We investigated the mechanism of immunological control of HIV-1 by a rare protective allele, HLA-B*67:01. We identified six novel HLA-B*67:01-restricted epitopes and found that T cells specific for four epitopes were significantly associated with good clinical outcomes, pVL and/or CD4 count. The wild type or cross-reactive sequences of three protective and immunodominant Pol and Gag epitopes were found in around 95% of the circulating HIV-1, indicating that T cells specific for three conserved or cross-reactive epitopes contributed to good clinical outcomes. One escape mutation (Nef71K) in the Nef protective epitope, which was selected by T cells restricted by either HLA allele in the HLA-B*67:01-C*07:02 haplotype, affected the HLA-B*67:01-restricted RY11-specific T-cell recognition. These results imply that the further accumulation of the Nef71K mutation in the population will negatively affect the control of HIV-1 replication by RY11-specific CD8+ T cells in HIV-1-infected HLA-B*67:01+ individuals. The present study demonstrated that conserved or cross-reactive epitope-specific T cells mainly contribute to control of HIV-1 by a rare protective allele, HLA-B*67:01. IMPORTANCE HLA-B57 is a relatively rare allele around world and the strongest protective HLA allele in Caucasians and African black individuals infected with HIV-1. Previous studies suggested that the advantage of this allele in HIV-1 disease progression is due to a strong functional ability of HLA-B57-restricted Gag-specific T cells and lower fitness of mutant viruses selected by the T cells. HLA-B*57 is a very rare allele and has not been reported as a protective allele in Asian countries, whereas a rare allele, HLA-B*67:01, was shown to be a protective allele in Japan. Therefore, the analysis of HLA-B*67:01-restricted T cells is important to clarify the mechanism of immunological control of HIV-1 by a rare protective HLA allele in Asia. We found that HLA-B*67:01-restricted T cells specific for three conserved or cross-reactive Gag and Pol epitopes are associated with good clinical outcomes in HLA-B*67:01+ individuals. It is expected that T cells specific for conserved or cross-reactive epitopes contribute to a curing treatment.

Host Cell Redox Alterations Promote Latent HIV-1 Reactivation through Atypical Transcription Factor Cooperativity.

Immune cell state alterations rewire HIV-1 gene expression, thereby influencing viral latency and reactivation, but the mechanisms are still unfolding. Here, using a screen approach on CD4+ T cell models of HIV-1 latency, we revealed Small Molecule Reactivators (SMOREs) with unique chemistries altering the CD4+ T cell state and consequently promoting latent HIV-1 transcription and reactivation through an unprecedented mechanism of action. SMOREs triggered rapid oxidative stress and activated a redox-responsive program composed of cell-signaling kinases (MEK-ERK axis) and atypical transcription factor (AP-1 and HIF-1α) cooperativity. SMOREs induced an unusual AP-1 phosphorylation signature to promote AP-1/HIF-1α binding to the latent HIV-1 proviral genome for its activation. Consistently, latent HIV-1 reactivation was compromised with pharmacologic inhibition of oxidative stress sensing or of cell-signaling kinases, and transcription factor's loss of expression, thus functionally linking the host redox-responsive program to viral transcriptional rewiring. Notably, SMOREs induced the redox program in primary CD4+ T cells and reactivated latent HIV-1 in aviremic patient samples alone and in combination with known latency-reversing agents, thus providing physiological relevance. Our findings suggest that manipulation of redox-sensitive pathways could be exploited to alter the course of HIV-1 latency, thus rendering host cells responsive to help achieve a sterilizing cure.

FCGR3A gene duplication, FcγRIIb-232TT and FcγRIIIb-HNA1a associate with an increased risk of vertical acquisition of HIV-1.

BACKGROUND: Some mother-to-child transmission (MTCT) studies suggest that allelic variations of Fc gamma receptors (FcγR) play a role in infant HIV-1 acquisition, but findings are inconsistent. To address the limitations of previous studies, the present study investigates the association between perinatal HIV-1 transmission and FcγR variability in three cohorts of South African infants born to women living with HIV-1. METHODS: This nested case-control study combines FCGR genotypic data from three perinatal cohorts at two hospitals in Johannesburg, South Africa. Children with perinatally-acquired HIV-1 (cases, n = 395) were compared to HIV-1-exposed uninfected children (controls, n = 312). All study participants were black South Africans and received nevirapine for prevention of MTCT. Functional variants were genotyped using a multiplex ligation-dependent probe amplification assay, and their representation compared between groups using logistic regression analyses. RESULTS: FCGR3A gene duplication associated with HIV-1 acquisition (OR = 10.27; 95% CI 2.00-52.65; P = 0.005) as did the FcγRIIb-232TT genotype even after adjusting for FCGR3A copy number and FCGR3B genotype (AOR = 1.72; 95%CI 1.07-2.76; P = 0.024). The association between FcγRIIb-232TT genotype and HIV-1 acquisition was further strengthened (AOR = 2.28; 95%CI 1.11-4.69; P = 0.024) if adjusted separately for FCGR2C c.134-96C>T. Homozygous FcγRIIIb-HNA1a did not significantly associate with HIV-1 acquisition in a univariate model (OR = 1.42; 95%CI 0.94-2.16; P = 0.098) but attained significance after adjustment for FCGR3A copy number and FCGR2B genotype (AOR = 1.55; 95%CI 1.01-2.38; P = 0.044). Both FcγRIIb-232TT (AOR = 1.83; 95%CI 1.13-2.97; P = 0.014) and homozygous FcγRIIIb-HNA1a (AOR = 1.66; 95%CI 1.07-2.57; P = 0.025) retained significance when birthweight and breastfeeding were added to the model. The common FCGR2A and FCGR3A polymorphisms did not associate with HIV-1 acquisition. CONCLUSIONS: Collectively, our findings suggest that the FcγRIIb-232TT genotype exerts a controlling influence on infant susceptibility to HIV-1 infection. We also show a role for less studied variants-FCGR3A duplication and homozygous HNA1a. These findings provide additional insight into a role for FcγRs in HIV-1 infection in children.

Phosphomimetic S207D Lysyl-tRNA Synthetase Binds HIV-1 5'UTR in an Open Conformation and Increases RNA Dynamics.

Interactions between lysyl-tRNA synthetase (LysRS) and HIV-1 Gag facilitate selective packaging of the HIV-1 reverse transcription primer, tRNALys3. During HIV-1 infection, LysRS is phosphorylated at S207, released from a multi-aminoacyl-tRNA synthetase complex and packaged into progeny virions. LysRS is critical for proper targeting of tRNALys3 to the primer-binding site (PBS) by specifically binding a PBS-adjacent tRNA-like element (TLE), which promotes release of the tRNA proximal to the PBS. However, whether LysRS phosphorylation plays a role in this process remains unknown. Here, we used a combination of binding assays, RNA chemical probing, and small-angle X-ray scattering to show that both wild-type (WT) and a phosphomimetic S207D LysRS mutant bind similarly to the HIV-1 genomic RNA (gRNA) 5'UTR via direct interactions with the TLE and stem loop 1 (SL1) and have a modest preference for binding dimeric gRNA. Unlike WT, S207D LysRS bound in an open conformation and increased the dynamics of both the PBS region and SL1. A new working model is proposed wherein a dimeric phosphorylated LysRS/tRNA complex binds to a gRNA dimer to facilitate tRNA primer release and placement onto the PBS. Future anti-viral strategies that prevent this host factor-gRNA interaction are envisioned.

Evaluation of the HIV-1 Polymerase Gene Sequence Diversity for Prediction of Recent HIV-1 Infections Using Shannon Entropy Analysis.

HIV-1 incidence is an important parameter for assessing the impact of HIV-1 interventions. The aim of this study was to evaluate HIV-1 polymerase (pol) gene sequence diversity for the prediction of recent HIV-1 infections. Complete pol Sanger sequences obtained from 45 participants confirmed to have recent or chronic HIV-1 infection were used. Shannon entropy was calculated for amino acid (aa) sequences for the entire pol and for sliding windows consisting of 50 aa each. Entropy scores for the complete HIV-1 pol were significantly higher in chronic compared to recent HIV-1 infections (p < 0.0001) and the same pattern was observed for some sliding windows (p-values ranging from 0.011 to <0.001), leading to the identification of some aa mutations that could discriminate between recent and chronic infection. Different aa mutation groups were assessed for predicting recent infection and their performance ranged from 64.3% to 100% but had a high false recency rate (FRR), which was decreased to 19.4% when another amino acid mutation (M456) was included in the analysis. The pol-based molecular method identified in this study would not be ideal for use on its own due to high FRR; however, this method could be considered for complementing existing serological assays to further reduce FRR.

Super high-resolution single-molecule sequence-based typing of HLA class I alleles in HIV-1 infected individuals in Ghana.

Polymorphisms in human leukocyte antigen (HLA) class I loci are known to have a great impact on disease progression in HIV-1 infection. Prevailing HIV-1 subtypes and HLA genotype distribution are different all over the world, and the HIV-1 and host HLA interaction could be specific to individual areas. Data on the HIV-1 and HLA interaction have been accumulated in HIV-1 subtype B- and C-predominant populations but not fully obtained in West Africa where HIV-1 subtype CRF02_AG is predominant. In the present study, to obtain accurate HLA typing data for analysis of HLA association with disease progression in HIV-1 infection in West African populations, HLA class I (HLA-A, -B, and -C) four-digit allele typing was performed in treatment-naïve HIV-1 infected individuals in Ghana (n = 324) by a super high-resolution single-molecule sequence-based typing (SS-SBT) using next-generation sequencing. Comparison of the SS-SBT-based data with those obtained by a conventional sequencing-based typing (SBT) revealed incorrect assignment of several alleles by SBT. Indeed, HLA-A*23:17, HLA-B*07:06, HLA-C*07:18, and HLA-C*18:02 whose allele frequencies were 2.5%, 0.9%, 4.3%, and 3.7%, respectively, were not determined by SBT. Several HLA alleles were associated with clinical markers, viral load and CD4+ T-cell count. Of note, the impact of HLA-B*57:03 and HLA-B*58:01, known as protective alleles against HIV-1 subtype B and C infection, on clinical markers was not observed in our cohort. This study for the first time presents SS-SBT-based four-digit typing data on HLA-A, -B, and -C alleles in Ghana, describing impact of HLA on viral load and CD4 count in HIV-1 infection. Accumulation of these data would facilitate high-resolution HLA genotyping, contributing to our understanding of the HIV-1 and host HLA interaction in Ghana, West Africa.

Inhibition of a Chromatin and Transcription Modulator, SLTM, Increases HIV-1 Reactivation Identified by a CRISPR Inhibition Screen.

Despite effective antiretroviral therapy, HIV-1 persistence in latent reservoirs remains a major obstacle to a cure. We postulate that HIV-1 silencing factors suppress HIV-1 reactivation and that inhibition of these factors will increase HIV-1 reactivation. To identify HIV-1 silencing factors, we conducted a genome-wide CRISPR inhibition (CRISPRi) screen using four CRISPRi-ready, HIV-1-d6-GFP-infected Jurkat T cell clones with distinct integration sites. We sorted cells with increased green fluorescent protein (GFP) expression and captured single guide RNAs (sgRNAs) via targeted deep sequencing. We identified 18 HIV-1 silencing factors that were significantly enriched in HIV-1-d6-GFPhigh cells. Among them, SLTM (scaffold attachment factor B-like transcription modulator) is an epigenetic and transcriptional modulator having both DNA and RNA binding capacities not previously known to affect HIV-1 transcription. Knocking down SLTM by CRISPRi significantly increased HIV-1-d6-GFP expression (by 1.9- to 4.2-fold) in three HIV-1-d6-GFP-Jurkat T cell clones. Furthermore, SLTM knockdown increased the chromatin accessibility of HIV-1 and the gene in which HIV-1 is integrated but not the housekeeping gene POLR2A. To test whether SLTM inhibition can reactivate HIV-1 and further induce cell death of HIV-1-infected cells ex vivo, we established a small interfering RNA (siRNA) knockdown method that reduced SLTM expression in CD4+ T cells from 10 antiretroviral therapy (ART)-treated, virally suppressed, HIV-1-infected individuals ex vivo. Using limiting dilution culture, we found that SLTM knockdown significantly reduced the frequency of HIV-1-infected cells harboring inducible HIV-1 by 62.2% (0.56/106 versus 1.48/106 CD4+ T cells [P = 0.029]). Overall, our study indicates that SLTM inhibition reactivates HIV-1 in vitro and induces cell death of HIV-1-infected cells ex vivo. Our study identified SLTM as a novel therapeutic target. IMPORTANCE HIV-1-infected cells, which can survive drug treatment and immune cell killing, prevent an HIV-1 cure. Immune recognition of infected cells requires HIV-1 protein expression; however, HIV-1 protein expression is limited in infected cells after long-term therapy. The ways in which the HIV-1 provirus is blocked from producing protein are unknown. We identified a new host protein that regulates HIV-1 gene expression. We also provided a new method of studying HIV-1-host factor interactions in cells from infected individuals. These improvements may enable future strategies to reactivate HIV-1 in infected individuals so that infected cells can be killed by immune cells, drug treatment, or the virus itself.

Biallelic, Selectable, Knock-in Targeting of CCR5 via CRISPR-Cas9 Mediated Homology Directed Repair Inhibits HIV-1 Replication.

Transplanting HIV-1 positive patients with hematopoietic stem cells homozygous for a 32 bp deletion in the chemokine receptor type 5 (CCR5) gene resulted in a loss of detectable HIV-1, suggesting genetically disrupting CCR5 is a promising approach for HIV-1 cure. Targeting the CCR5-locus with CRISPR-Cas9 was shown to decrease the amount of CCR5 expression and HIV-1 susceptibility in vitro as well as in vivo. Still, only the individuals homozygous for the CCR5-Δ32 frameshift mutation confer complete resistance to HIV-1 infection. In this study we introduce a mechanism to target CCR5 and efficiently select for cells with biallelic frameshift insertion, using CRISPR-Cas9 mediated homology directed repair (HDR). We hypothesized that cells harboring two different selectable markers (double positive), each in one allele of the CCR5 locus, would carry a frameshift mutation in both alleles, lack CCR5 expression and resist HIV-1 infection. Inducing double-stranded breaks (DSB) via CRISPR-Cas9 leads to HDR and integration of a donor plasmid. Double-positive cells were selected via fluorescence-activated cell sorting (FACS), and CCR5 was analyzed genetically, phenotypically, and functionally. Targeted and selected populations showed a very high frequency of mutations and a drastic reduction in CCR5 surface expression. Most importantly, double-positive cells displayed potent inhibition to HIV-1 infection. Taken together, we show that targeting cells via CRISPR-Cas9 mediated HDR enables efficient selection of mutant cells that are deficient for CCR5 and highly resistant to HIV-1 infection.

Extending the Coding Potential of Viral Genomes with Overlapping Antisense ORFs: A Case for the De Novo Creation of the Gene Encoding the Antisense Protein ASP of HIV-1.

Gene overprinting occurs when point mutations within a genomic region with an existing coding sequence create a new one in another reading frame. This process is quite frequent in viral genomes either to maximize the amount of information that they encode or in response to strong selective pressure. The most frequent scenario involves two different reading frames in the same DNA strand (sense overlap). Much less frequent are cases of overlapping genes that are encoded on opposite DNA strands (antisense overlap). One such example is the antisense ORF, asp in the minus strand of the HIV-1 genome overlapping the env gene. The asp gene is highly conserved in pandemic HIV-1 strains of group M, and it is absent in non-pandemic HIV-1 groups, HIV-2, and lentiviruses infecting non-human primates, suggesting that the ~190-amino acid protein that is expressed from this gene (ASP) may play a role in virus spread. While the function of ASP in the virus life cycle remains to be elucidated, mounting evidence from several research groups indicates that ASP is expressed in vivo. There are two alternative hypotheses that could be envisioned to explain the origin of the asp ORF. On one hand, asp may have originally been present in the ancestor of contemporary lentiviruses, and subsequently lost in all descendants except for most HIV-1 strains of group M due to selective advantage. Alternatively, the asp ORF may have originated very recently with the emergence of group M HIV-1 strains from SIVcpz. Here, we used a combination of computational and statistical approaches to study the genomic region of env in primate lentiviruses to shed light on the origin, structure, and sequence evolution of the asp ORF. The results emerging from our studies support the hypothesis of a recent de novo addition of the antisense ORF to the HIV-1 genome through a process that entailed progressive removal of existing internal stop codons from SIV strains to HIV-1 strains of group M, and fine tuning of the codon sequence in env that reduced the chances of new stop codons occurring in asp. Altogether, the study supports the notion that the HIV-1 asp gene encodes an accessory protein, providing a selective advantage to the virus.

Amino acid substitutions at the HIV-1 transframe region significantly impair virus infectivity.

A transframe region within HIV-1 Gag-Pol (referred to as p6* or p6pol), directly linked to the protease (PR) N-terminus, plays a pivotal role in modulating PR activation. To identify specific p6* residues involved in PR activation, we created a series of p6* mutants by making substitutions for conserved p6* residues. Our results indicate that some p6* mutants were defective in terms of virus infectivity, despite displaying a wild-type virus particle processing pattern. Mutations at p6* F8 reduced virus infectivity associated with insufficient virus processing, due in part to impaired PR maturation and RT packaging. Our data strongly suggest that conserved Phe (F) residues at position 8 of p6* are involved in the PR maturation process.

Th1 cytokine gene polymorphism and the corresponding plasma cytokine levels: A comparative study in HIV-1 positive and exposed uninfected infants.

The pro-inflammatory (Th1) cytokines namely interleukin (IL)-2, IL-6, IL-12, interferon (IFN)-γ, tumor necrosis factor-α (TNF-α) are vital in the clearance of HIV infection. This prospective cohort study aimed to evaluate the polymorphisms of Th1 cytokine genes and their corresponding plasma cytokine levels in HIV-1 positive and exposed uninfected (EU) infants born to HIV-1 positive mothers. CD4 count, viral load of HIV-1 positive mothers was done using commercially available reagents. Cytokine genotyping analysis and levels were done in 20 HIV-1 positive and 54 EU infants. The polymorphisms of Th1 cytokines were done using the PCR-SSP method. Plasma cytokine levels were estimated using Bio-Plex-Pro cytokine assay (BIO-RAD; USA). Results revealed treatment status of the mothers and viral load were the two confounding factors having a significant effect on HIV status of the infant. TNF-α GG genotype is significantly higher in EU infants as compared with HIV-1 positive infants. GG genotype was associated with high TNF- α levels in HIV-1 positive infants but the difference was not statistically significant. HIV-1 positive infants with -IFN-γ (+874) TT genotype was significantly associated with high IFN-γ levels. To the best of our knowledge, this is the first study reporting the role of Th1 cytokine gene polymorphisms and their corresponding plasma cytokine levels in HIV-1 positive and EU infants from India.