Untargeted Metabolomic Study of Lung Cancer Patients after Surgery with Curative Intent.

Lung cancer (LC) is a leading cause of mortality, claiming more than 1.8 million deaths per year worldwide. Surgery is one of the most effective treatments when the disease is in its early stages. The study of metabolic alterations after surgical intervention with curative intent could be used to assess the response to treatment or the detection of cancer recurrence. In this study, we have evaluated the metabolomic profile of serum samples (n = 110) from preoperative (PRE) and postoperative (POST) LC patients collected at two different time points (1 month, A; 3-6 months, B) with respect to healthy people. An untargeted metabolomic platform based on reversed phase (RP) and hydrophilic interaction chromatography (HILIC), using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry (MS), was applied (MassIVE ID MSV000092213). Twenty-two altered metabolites were annotated by comparing all the different studied groups. DG(14,0/22:1), stearamide, proline, and E,e-carotene-3,3'-dione were found altered in PRE, and their levels returned to those of a baseline control group 3-6 months after surgery. Furthermore, 3-galactosyllactose levels remained altered after intervention in some patients. This study provides unique insights into the metabolic profiles of LC patients after surgery at two different time points by combining complementary analytical methods.

Metallomic Signatures of Lung Cancer and Chronic Obstructive Pulmonary Disease.

Lung cancer (LC) is the leading cause of cancer deaths, and chronic obstructive pulmonary disease (COPD) can increase LC risk. Metallomics may provide insights into both of these tobacco-related diseases and their shared etiology. We conducted an observational study of 191 human serum samples, including those of healthy controls, LC patients, COPD patients, and patients with both COPD and LC. We found 18 elements (V, Al, As, Mn, Co, Cu, Zn, Cd, Se, W, Mo, Sb, Pb, Tl, Cr, Mg, Ni, and U) in these samples. In addition, we evaluated the elemental profiles of COPD cases of varying severity. The ratios and associations between the elements were also studied as possible signatures of the diseases. COPD severity and LC have a significant impact on the elemental composition of human serum. The severity of COPD was found to reduce the serum concentrations of As, Cd, and Tl and increased the serum concentrations of Mn and Sb compared with healthy control samples, while LC was found to increase Al, As, Mn, and Pb concentrations. This study provides new insights into the effects of LC and COPD on the human serum elemental profile that will pave the way for the potential use of elements as biomarkers for diagnosis and prognosis. It also sheds light on the potential link between the two diseases, i.e., the evolution of COPD to LC.

Contribution of the HIV-1 Envelope Glycoprotein to AIDS Pathogenesis and Clinical Progression.

In the absence of antiviral therapy, HIV-1 infection progresses to a wide spectrum of clinical manifestations that are the result of an entangled contribution of host, immune and viral factors. The contribution of these factors is not completely established. Several investigations have described the involvement of the immune system in the viral control. In addition, distinct HLA-B alleles, HLA-B27, -B57-58, were associated with infection control. The combination of these elements and antiviral host restriction factors results in different clinical outcomes. The role of the viral proteins in HIV-1 infection has been, however, less investigated. We will review contributions dedicated to the pathogenesis of HIV-1 infection focusing on studies identifying the function of the viral envelope glycoprotein (Env) in the clinical progression because of its essential role in the initial events of the virus life-cycle. Some analysis showed that inefficient viral Envs were dominant in non-progressor individuals. These poorly-functional viral proteins resulted in lower cellular activation, viral replication and minor viral loads. This limited viral antigenic production allows a better immune response and a lower immune exhaustion. Thus, the properties of HIV-1 Env are significant in the clinical outcome of the HIV-1 infection and AIDS pathogenesis.

The Characteristics of the HIV-1 Env Glycoprotein Are Linked With Viral Pathogenesis.

The understanding of HIV-1 pathogenesis and clinical progression is incomplete due to the variable contribution of host, immune, and viral factors. The involvement of viral factors has been investigated in extreme clinical phenotypes from rapid progressors to long-term non-progressors (LTNPs). Among HIV-1 proteins, the envelope glycoprotein complex (Env) has been concentrated on in many studies for its important role in the immune response and in the first steps of viral replication. In this study, we analyzed the contribution of 41 Envs from 24 patients with different clinical progression rates and viral loads (VLs), LTNP-Elite Controllers (LTNP-ECs); Viremic LTNPs (vLTNPs), and non-controller individuals contemporary to LTNPs or recent, named Old and Modern progressors. We studied the Env expression, the fusion and cell-to-cell transfer capacities, as well as viral infectivity. The sequence and phylogenetic analysis of Envs were also performed. In every functional characteristic, the Envs from subjects with viral control (LTNP-ECs and vLTNPs) showed significant lower performance compared to those from the progressor individuals (Old and Modern). Regarding sequence analysis, the variable loops of the gp120 subunit of the Env (i.e., V2, V4, and mainly V5) of the progressor individuals showed longer and more glycosylated sequences than controller subjects. Therefore, HIV-1 Envs from virus of patients presenting viremic control and the non-progressor clinical phenotype showed poor viral functions and shorter sequences, whereas functional Envs were associated with virus of patients lacking virological control and with progressor clinical phenotypes. These correlations support the role of Env genotypic and phenotypic characteristics in the in vivo HIV-1 infection and pathogenesis.

Immunoescape of HIV-1 in Env-EL9 CD8 + T cell response restricted by HLA-B*14:02 in a Non progressor who lost twenty-seven years of HIV-1 control.

BACKGROUND: Long-Term Non-Progressors (LTNPs) are untreated Human Immunodeficiency virus type 1 (HIV-1) infected individuals able to control disease progression for prolonged periods. However, the LTNPs status is temporary, as viral load increases followed by decreases in CD4 + T-cell counts. Control of HIV-1 infection in LTNPs viremic controllers, have been associated with effective immunodominant HIV-1 Gag-CD8 + T-cell responses restricted by protective HLA-B alleles. Individuals carrying HLA-B*14:02 control HIV-1 infection is related to an immunodominant Env-CD8 + T-cell response. Limited data are available on the contribution of HLA-B*14:02 CD8 + T -cells in LTNPs. RESULTS: In this study, we performed a virological and immunological detailed analysis of an HLA-B*14:02 LNTP individual that lost viral control (LVC) 27 years after HIV-1 diagnosis. We analysed viral evolution and immune escape in HLA-B*14:02 restricted CD8 + T -cell epitopes and identified viral evolution at the Env-EL9 epitope selecting the L592R mutation. By IFN-γ ELISpot and immune phenotype, we characterized HLA- B*14:02 HIV-1 CD8 + T cell responses targeting, Gag-DA9 and Env-EL9 epitopes before and after LVC. We observed an immunodominant response against the Env-EL9 epitope and a decreased of the CD8 T + cell response over time with LVC. Loss of Env-EL9 responses was concomitant with selecting K588R + L592R mutations at Env-EL9. Finally, we evaluated the impact of Env-EL9 escape mutations on HIV-1 infectivity and Env protein structure. The K588R + L592R escape variant was directly related to HIV-1 increase replicative capacity and stability of Env at the LVC. CONCLUSIONS: These findings support the contribution of immunodominant Env-EL9 CD8 + T-cell responses and the imposition of immune escape variants with higher replicative capacity associated with LVC in this LNTP. These data highlight the importance of Env-EL9 specific-CD8 + T-cell responses restricted by the HLA-B*14:02 and brings new insights into understanding long-term HIV-1 control mediated by Env mediated CD8 + T-cell responses.

High-Risk Sexual Practices Contribute to HIV-1 Double Infection Among Men Who Have Sex with Men in Madrid.

Data on the prevalence of double infection (DI) in HIV individuals are lacking in Spain. To fill this gap, we analyzed the prevalence of DI in a cohort of men who have sex with men (MSM) and examined factors contributing to DI. We selected 81 MSM attending Centro Sanitario Sandoval, a sexually transmitted diseases clinic in Madrid. We obtained by ultra-deep sequencing the proviral sequences in gag and env genes and performed a phylogenetic analysis for the identification of DI. Clinical, behavioral, host, and viral factors were studied for its association with DI. We detected six individuals with DI and one case of superinfection with a global prevalence of 8.6%. The genetic distance among the subtype B viruses in monoinfected individuals (24.4%) was lower than the distance between the two viruses in subtype B DI individuals (29.5%). Individuals with a high number of sexual contacts (>25 partners/year) had an 8.66 times higher risk of DI (p = .017). In this MSM cohort the prevalence of HIV DI was estimated at 8.6%. DI was strongly associated with the number of sexual partners. Because of the pathogenic consequences of HIV DI, this high prevalence should promote public health programs targeted at high-risk population such as MSM for the control of HIV infection and DI. HIV DI should be considered for a better clinical management of these individuals.

Characterizing the antiviral effect of an ATR inhibitor on human immunodeficiency virus type 1 replication.

In the search for new antiviral therapies against human immunodeficiency virus type 1 (HIV-1), several cellular targets are being investigated. Ataxia telangiectasia and Rad3-related protein (ATR) has been implicated in HIV-1 replication, namely during retroviral DNA integration. We studied the effect of the ATR inhibitor ETP-46464 on HIV-1 replication in peripheral blood mononuclear cells (PBMCs) and in the persistently HIV-1-infected cell line H61-D. After treatment with ETP-46464, a significant decrease in virus production was observed in both cell systems. Quantification of viral DNA forms in the acutely infected PBMCs suggests that inhibition could take place in the early phase of the viral life cycle before viral DNA integration. Moreover, after treatment of H61-D cells with 3'-azido-3'-deoxythymidine (AZT), which blocks new reverse transcription events, ETP-46464 decreased viral production, suggesting that inhibition of viral replication occurred in the late phase of the life cycle after viral DNA integration. A decrease in virus production after transfection of 293T cells with an HIV-1 infectious molecular clone also suggested that the effect of ETP-46464 is exerted at a post-integration step. We propose that ETP-46464 produces its inhibitory effect on HIV-1 replication by acting in both the early and late phases of the retroviral replication cycle. Thus, ATR could represent a new target for inhibition of HIV-1 replication.

Permanent control of HIV-1 pathogenesis in exceptional elite controllers: a model of spontaneous cure.

Elite controllers (EC) represent a small subset of HIV-1-infected people that spontaneously control viral replication. However, natural virological suppression and absence of immune dysfunction are not always long-term sustained. We define exceptional EC (EEC) as HIV-1 subjects who maintain the EC characteristics without disease progression for more than 25 years. We analyzed three EEC, diagnosed between 1988 and 1992, who never showed signs of clinical disease progression in absence of any antiretroviral treatment. A comprehensive clinical, virological, and immunological study was performed. The individuals simultaneously exhibited ≥3 described host protective alleles, low levels of total HIV-1 DNA (<20 copies/106 CD4+ T-cells) without evidence of replication-competent viruses (<0.025 IUPM), consistent with high levels of defective genomes, strong cellular HIV-1-specific immune response, and a high poly-functionality index (>0.50). Inflammation levels of EEC were similar to HIV-1 negative donors. Remarkably, they showed an exceptional lack of viral evolution and 8-fold lower genetic diversity (<0.01 s/n) in env gene than other EC. We postulate that these EEC represent cases of spontaneous functional HIV-1 cure. A non-functional and non-genetically evolving viral reservoir along with an HIV-1-specific immune response seems to be key for the spontaneous functional cure.

Elite controllers and lessons learned for HIV-1 cure.

Following the success of HIV-1 antiviral treatment that maintains undetectable levels of viral replication and lack of clinical progression, the design of an HIV-1 cure for patients became the next objective. The success of the treated individuals together with the identification of subjects that spontaneously control the clinical progression for long periods, such as long-term non-progressors (LTNPs) and particularly LTNP Elite Controllers (LTNP EC) have shed hope for the feasibility of a potential cure. Although a successful cure has not been attained yet, these patients have provided critical information on the mechanisms involved in the clinical control such as host genetic factors, as well as strong immune responses against the virus. Less attention has been paid to virological factors, particularly the association of the genetic variability and the control of viral infection. Considering all these studies, it has become clear that a combination of several host, immune and viral factors is needed to attain control of the viral replication control and the non-progressor clinical phenotype. Because this control can be reached through different combinations of factors, this group of individuals is not homogenous. As HIV-1 cure has been shown to be extremely difficult to achieve, a more feasible objective is the functional cure of the viral infection. After the analysis of multiple studies on the mechanisms of control in LTNP EC, we found subjects with various host protective factors and prolonged viral control. These subjects present a complete lack of evolution after more than 20-30 years of infection, stable levels of CD4+ cells (>400-500 cells/µl), a strong immune response, and no signs of clinical progression. We propose that individuals with these characteristics could have attained a functional cure of the HIV-1 infection.

HIV-1 envelope glycoproteins isolated from Viremic Non-Progressor individuals are fully functional and cytopathic.

In untreated HIV-1-infected individuals, viremia is positively associated with disease progression. However, some viremic non progressors (VNPs) individuals show paradoxical high CD4+ T cell counts. HIV-1 envelope glycoprotein complex (Env) is a major cytopathic determinant in viral replication; therefore, we have deeply characterized Env function in this rare clinical phenotype. Full-length Env clones isolated from individuals with Viral Load (VL) > 10,000 copies/mL classified as VNPs (n = 15) or rapid progressors (RPs, n = 17) were geno- and phenotypically analyzed by determining diversity, expression, CD4 binding/signaling, fusogenicity, infectivity and autophagy induction. Selected Env clones from VNPs and RPs (n = 32) showed similar expression, fusion and infection abilities. Env clones from both groups showed similar affinity for CD4 during cell-to-cell transmission and consistently induced similar levels of CD4 signaling, measured by α-tubulin acetylation. Moreover, we demonstrate for the first time that primary Env clones from VNP and RP induce autophagy in uninfected cells and that this feature correlated with fusogenic capacity but was unrelated to disease progression. In conclusion, our data suggest that Env clones from VNP individuals are fully functional. Therefore, the paradoxical CD4+ T cell count stability coexisting with high levels of viral replication is unrelated to Env function.

Viral Characteristics Associated with the Clinical Nonprogressor Phenotype Are Inherited by Viruses from a Cluster of HIV-1 Elite Controllers.

A small group of HIV-1-infected individuals, called long-term nonprogressors (LTNPs), and in particular a subgroup of LTNPs, elite controllers (LTNP-ECs), display permanent control of viral replication and lack of clinical progression. This control is the result of a complex interaction of host, immune, and viral factors. We identified, by phylogenetic analysis, a cluster of LTNP-ECs infected with very similar low-replication HIV-1 viruses, suggesting the contribution of common viral features to the clinical LTNP-EC phenotype. HIV-1 envelope (Env) glycoprotein mediates signaling and promotes HIV-1 fusion, entry, and infection, being a key factor of viral fitness in vitro, cytopathicity, and infection progression in vivo Therefore, we isolated full-length env genes from viruses of these patients and from chronically infected control individuals. Functional characterization of the initial events of the viral infection showed that Envs from the LTNP-ECs were ineffective in the binding to CD4 and in the key triggering of actin/tubulin-cytoskeleton modifications compared to Envs from chronic patients. The viral properties of the cluster viruses result in a defective viral fusion, entry, and infection, and these properties were inherited by every virus of the cluster. Therefore, inefficient HIV-1 Env functions and signaling defects may contribute to the low viral replication capacity and transmissibility of the cluster viruses, suggesting a direct role in the LTNP-EC phenotype of these individuals. These results highlight the important role of viral characteristics in the LTNP-EC clinical phenotype. These Env viral properties were common to all the cluster viruses and thus support the heritability of the viral characteristics.IMPORTANCE HIV-1 long-term nonprogressor elite controller patients, due to their permanent control of viral replication, have been the object of numerous studies to identify the factors responsible for this clinical phenotype. In this work, we analyzed the viral characteristics of the envelopes of viruses from a phylogenetic cluster of LTNP-EC patients. These envelopes showed ineffective binding to CD4 and the subsequent signaling activity to modify actin/tubulin cytoskeletons, which result in low fusion and deficient entry and infection capacities. These Env viral characteristics could explain the nonprogressor clinical phenotype of these patients. In addition, these inefficient env viral properties were present in all viruses of the cluster, supporting the heritability of the viral phenotype.

Factors Leading to the Loss of Natural Elite Control of HIV-1 Infection.

HIV-1 elite controllers (EC) maintain undetectable viral loads (VL) in the absence of antiretroviral treatment. However, these subjects have heterogeneous clinical outcomes, including a proportion that loses HIV-1 control over time. In this work, we compared, in a longitudinal design, transient EC, analyzed before and after the loss of virological control, with persistent EC. The aim was to identify factors leading to the loss of natural virological control of HIV-1 infection with a longitudinal retrospective study design. Gag-specific T-cell responses were assessed by in vitro intracellular polycytokine production quantified by flow cytometry. Viral diversity determinations and sequence dating were performed in proviral DNA by PCR amplification at limiting dilution of env and gag genes. The expression profile of 70 serum cytokines and chemokines was assessed by multiplex immunoassays. We identified transient EC as subjects with low Gag-specific T-cell polyfunctionality, high viral diversity, and high proinflammatory cytokine levels before the loss of control. Gag-specific T-cell polyfunctionality was inversely associated with viral diversity in transient controllers before the loss of control (r = -0.8; P = 0.02). RANTES was a potential biomarker of transient control. This study identified virological and immunological factors, including inflammatory biomarkers associated with two different phenotypes within EC. These results may allow a more accurate definition of EC, which could help in better clinical management of these individuals and in the development of future curative approaches.IMPORTANCE There is a rare group of HIV-infected patients who have the extraordinary capacity to maintain undetectable viral load levels in the absence of antiretroviral treatment, the so-called HIV-1 elite controllers (EC). However, there is a proportion within these subjects that eventually loses this capability. In this work, we found differences in virological and immune factors, including soluble inflammatory biomarkers, between subjects with persistent control of viral replication and EC that will lose virological control. The identification of these factors could be a key point for a right medical care of those EC who are going to lose natural control of viral replication and for the design of future immunotherapeutic strategies using as a model the natural persistent control of HIV infection.

Human Immunodeficiency Virus Type 1 Two-Long Terminal Repeat Circles: A Subject for Debate.

HIV-1 infections are characterized by the integration of the reverse transcribed genomic RNA into the host chromosomes making up the provirus. In addition to the integrated proviral DNA, there are other forms of linear and circular unintegrated viral DNA in HIV-1-infected cells. One of these forms, known as two-long terminal repeat circles, has been extensively studied and characterized both in in vitro infected cells and in cells from patients. Detection of two-long terminal repeat circles has been proposed as a marker of antiretroviral treatment efficacy or ongoing replication in patients with undetectable viral load. But not all authors agree with this use because of the uncertainty about the lifespan of the two-long terminal repeat circles. We review the major studies estimating the half-life of the two-long terminal repeat circles as well as those proposing its detection as a marker of ongoing replication or therapeutic efficacy. We also review the characteristic of these circular forms and the difficulties in its detection and quantification. The variety of approaches and methods used in the two-long terminal repeat quantification as well as the low reliability of some methods make the comparison between results difficult. We conclude that it is not possible to draw a clear supposition about the lifespan of two-long terminal repeat circles and consequently they should not be used as a marker of ongoing replication without a careful analysis of the methods and results.

HIV-1 Dual Infected LTNP-EC Patients Developed an Unexpected Antibody Cross-Neutralizing Activity.

This study evaluated the neutralization breadth in dually infected (DI) HIV-1 long-term non-progressor elite controller patients (LTNP-EC) using a representative minipanel of 6 viruses from 5 different subtypes. Our results showed an improved neutralization breadth in DI LTNP-EC patients when compared with matched LTNP single-infected patients. The role of viral diversity in neutralization was estimated with the Shannon Entropy and the p-distance in viral quasispecies. We found a positive correlation between neutralization breadth and diversity within the viral quasispecies. This correlation could explain why a group of LTNP-EC patients developed a broad neutralizing response despite having undetectable levels of viremia.

Identification of a cluster of HIV-1 controllers infected with low replicating viruses.

Long term non-progressor patients (LTNPs) are characterized by the natural control of HIV-1 infection. This control is related to host genetic, immunological and virological factors. In this work, phylogenetic analysis of the proviral nucleotide sequences in env gene from a Spanish HIV-1 LTNPs cohort identified a cluster of 6 HIV-1 controllers infected with closely-related viruses. The patients of the cluster showed common clinical and epidemiological features: drug user practices, infection in the same city (Madrid, Spain) and at the same time (late 70's-early 80's). All cluster patients displayed distinct host alleles associated with HIV control. Analysis of the virus envelope nucleotide sequences showed ancestral characteristic, lack of evolution and presence of rare amino-acids. Biological characterization of recombinant viruses with the envelope proteins from the cluster viruses showed very low replicative capacity in TZMbl and U87-CD4/CCR5 cells. The lack of clinical progression in the viral cluster patients with distinct combinations of protective host genotypes, but infected by low replicating viruses, indicate the important role of the virus in the non-progressor phenotype in these patients.

Evidence of ongoing replication in a human immunodeficiency virus type 1 persistently infected cell line.

Human immunodeficiency virus type 1 (HIV-1) persistently infected cell lines are characterized by the continuous viral production without cytopathic effect. However, it is not completely clear if this production is contributed only by viral transcription or also by new cycles of viral replication. We studied an HIV-1 persistently infected cell line, designated H61-D, providing evidence of new replication cycles as sustained by: (i) a decrease in viral production, measured by p24 protein, after treatment of the culture with 3'-azydo-3'-deoxythymydine; (ii) detection of new integration events in the course of cell culture, and (iii) finding of two-long-terminal repeat circles in the cells. H61-D cells were not infected by cell-free virus, but infection was possible by co-culture with another productive-infected cell line. In conclusion, ongoing viral replication is taking place in H61-D persistent cells and new infections are mediated by a cell-to-cell spread mechanism.

Mutagen-mediated enhancement of HIV-1 replication in persistently infected cells.

Lethal mutagenesis, a new antiviral strategy to extinguish virus through elevated mutation rates, was explored in H61-D cells an HIV-1 persistently infected lymphoid cell line. Three mutagenic agents: 5-hydroxy-2(')-deoxycytidine (5-OHdC), 5-fluorouracil (5-FU) and 2,2(')-difluoro-2(')-deoxycytidine (gemcitabine) were used. After 54 passages, treatments with 5-FU and gemcitabine reduced virus infectivity, p24 and RT activity. Treatment with the pyrimidine analog 5-OHdC resulted in increases of p24 production, RT activity and infectivity. Rise in viral replication by 5-OHdC during HIV-1 persistence is in contrast with its inhibitory effect in acute infections. Viral replication enhancement by 5-OHdC was associated with an increase in intracellular HIV-1 RNA mutations. Mechanisms of HIV-1 replication enhancement by 5-OHdC are unknown but some potential factors are discussed. Increase of HIV-1 replication by 5-OHdC cautions against the use, without previous analyses, of mutagenic nucleoside analogs for AIDS treatment.

A combination of defective DNA and protective host factors are found in a set of HIV-1 ancestral LTNPs.

We studied viral evolution in three HIV-1 ancestral patients from a group of LTNPs; although some minor sequences showing viral evolution were detected in all patients, the extremely low viral evolution of their viruses was shown by the phylogenetic analysis of the env sequences. Complete nucleotide sequencing of viral DNA showed the major presence of deletions. In two patients, deletions of 1088 and 228 nucleotides mapped to 5' LTR-gag region; in the other, a 247 nucleotide deletion was positioned in pol gene up to the vif ORF. These deleted genomes became dominant during follow up. Patient's viruses displayed 13 common mutations in conserved residues, from the 5' LTR to the nef gene. These mutations provided evidence of a common origin. Regarding host characteristics, one patient had HLA B2705/B5801; another B1402/B5701; whereas a third showed B3901/B4402 and was Delta32-CCR5 heterozygous. These HIV controllers presented a combination of deleted viral genomes and host protective factors.

Human immunodeficiency virus type 1 chronic infection is associated with different gene expression in MT-4, H9 and U937 cell lines.

To investigate cellular factors involved in HIV-1 chronic infection, three cell lines chronically infected with the same HIV-1 viral isolate (s61) were studied by cDNA microarray analysis. Two T cell lines, H61 and M61, showed the characteristics of a persistent infection whereas U61 cell line displayed a latent infection pattern. Analysis of genes with altered expression in the three cell lines revealed evidence of apoptosis control by up-regulation of anti-apoptotic genes and down-regulation of pro-apoptotic genes. In addition, cell cycle control was affected in the two persistent T cell lines particularly through the down-regulation of cyclin-dependent kinase inhibitor 1A (CDKN1A/p21). Moreover, each cell line showed specific characteristics, like in M61 cells, genes related with cellular activation and with cell migration and motility. In U61 cells, genes associated with immune response were activated. Genes with altered expression in our experiments, and not previously related with HIV such as ANXA 1 or CFLAR were detected and validated. This work revealed that different cell mechanism such as control of apoptosis and cell cycle are important for "in vitro" HIV-1 chronic infections, and discovered new genes previously not related with HIV-1 replication.

HIV-1 protease dimer interface mutations that compensate for viral reverse transcriptase instability in infectious virions.

Mature enzymes encoded within the human immunodeficiency virus type 1 (HIV-1) genome (protease (PR), reverse transcriptase (RT) and integrase (IN)) derive from proteolytic processing of a large polyprotein (Gag-Pol). Gag-Pol processing is catalyzed by the viral PR, which is active as a homodimer. The HIV-1 RT functions as a heterodimer (p66/p51) composed of subunits of 560 and 440 amino acid residues, respectively. Both subunits have identical amino acid sequence, but p51 lacks 120 residues that are removed by the HIV-1 PR during viral maturation. While p66 is the catalytic subunit, p51 has a primarily structural role. Amino acid substitutions affecting the stability of p66/p51 (i.e. F130W) have a deleterious effect on viral fitness. Previously, we showed that the effects of F130W are mediated by p51 and can be compensated by mutation T58S. While studying the dynamics of emergence of the compensatory mutation, we observed that mutations in the viral PR-coding region were selected in HIV clones containing the RT substitution F130W, before the imposition of T58S/F130W mutations. The PR mutations identified (G94S and T96S) improved the replication capacity of the F130W mutant virus. By using a trans-complementation assay, we demonstrate that the loss of p66/p51 heterodimer stability caused by Trp130 can be attributed to an increased susceptibility of RT to viral PR degradation. Recombinant HIV-1 PRs bearing mutations G94S or T96S showed decreased dimer stability and reduced catalytic efficiency. These results were consistent with crystallographic data showing the location of both residues in the PR dimerization interface.