Hepatitis C virus (HCV)/HIV co-infected patients have more rapid progression of liver fibrosis and only modest cure rates (sustained virologic responses, SVRs) when compared to HCV monoinfected patients.
We compared the virologic responses of either twice-weekly peginterferon-α-2a 180 µg/week (for 4 weeks, followed by weekly dosing) or weekly peginterferon-α-2a 180 µg/week, and weight-based ribavirin (1–1.2 g/day), among HIV/HCV co-infected genotype-1 individuals.
Patients receiving the investigational dosing had lower levels of HCV RNA at all time points after initiation of therapy. More patients on this arm achieved clinically relevant early virological responses at weeks 1, 2, 4, 12, and 24. The enhanced early virologic response observed with the investigational arm was associated with a higher induction of interferon-stimulated genes. This early double dose regimen also resulted in a rapid normalization of liver enzymes. Twice-weekly peginterferon-α-2a was associated with more frequent early virological responses with similar safety profiles when compared with standard therapy.
Our results, when confirmed in larger randomized clinical trials, may provide a novel therapeutic approach to improve SVR among HIV/HCV co-infected patients, especially African–American patients.
hepatitis C virus; HIV; sustained virologic response; twice-weekly interferon; viral kinetics
The humoral immune response following acute HIV-1 infection is delayed and ineffective. The HIV-1 envelope protein gp120 binds to and signals through α4β7 on T cells. We show that gp120 also binds and signals through α4β7 on naïve B cells, resulting in an abortive proliferative response. In primary B cells gp120 signaling through α4β7 resulted in increased expression of the immunosuppressive cytokine TGF-β1 and the B cell inhibitory receptor FcRL4. Co-culture of B cells with HIV-1-infected autologous CD4+ T cells also increased B cell FcRL4 expression. These findings indicate that, in addition to mediating chronic immune activation, viral proteins can contribute directly to HIV-1-associated B cell dysfunction. Our studies provide a mechanism whereby the virus may subvert the early HIV-1-specific humoral immune response.
Interleukin-27 (IL-27) is a pleiotropic cytokine which plays important and diverse roles in the immune system. We have previously demonstrated that IL-27 induces potent anti-viral effects against HIV-1, HIV-2, SIV, HSV-2, KSHV and influenza viruses in macrophages. This induction occurred in an Interferon (IFN) independent manner and involved down regulation of SPTBN1. MicroRNAs (miRNAs) are critical regulators of mRNA translation and turnover. There have been reports that some miRNAs inhibit viral replication. In this study, we hypothesized that IL-27 could induce the expression of novel miRNAs in macrophages which may have functional relevance in terms of anti-viral activity and primary monocytes were differentiated into macrophages using either M-CSF (M-Mac) or a combination of M-CSF and IL-27 (I-Mac) for seven days. Following this, total RNA was extracted from these cells and deep sequencing was performed, in parallel with gene expression microarrays. Using the novel miRNA discovery software, miRDeep, seven novel miRNAs were discovered in these macrophages. Four of which were preferentially expressed in I-Mac (miR-SX1, -SX2, -SX3 and -SX6) whilst three were detected in both M-Mac and I-Mac (miR-SX4, -SX5 and -SX7). The expression of six of the seven novel miRNAs was highly correlated with qRT-PCR using specific primer/probes designed for the novel miRNAs. Gene expression microarray further demonstrated that a number of genes were potentially targeted by these differentially expressed novel miRNAs. Finally, several of these novel miRNAs (miR-SX1, -SX4, -SX5, -SX6 and -SX7) were shown to target the open reading frames of a number of viruses (including HSV-1, HSV-2 and HHV-8) which may partially explain the anti-viral properties observed.
Interleukin-27; macrophages; MicroRNAs; HIV; HSV-1; HSV-2; HHV-8
This study examines the distinct gene expression profile of peripheral blood mononuclear cells from patients with chronic hepatitis C infection and mixed cryoglobulinemic (MC) vasculitis. Our DNA microarray analysis indicates that hepatitis C virus (HCV)-associated MC vasculitis is characterized by compromised neutrophil function, impaired chemotaxis, and increased interferon-stimulated gene (ISG) expression, contributing to overall MC pathogenesis and end-organ damage. Increased ISG expression is suggestive of an enhanced endogenous interferon gene signature. PBMC depletion assays demonstrate that this increased expression is likely due to an activation of monocytes and not a direct result of B cell expansion. Notably, this monocyte activation of ISG expression in HCV-associated MC vasculitis suggests a poor predictor status of interferon-based treatment. Further analysis of PBMC gene expression profiles before and after in vivo B cell depletion therapy is critical to completely understanding the mechanisms of MC vasculitis pathogenesis.
hepatitis C; mixed cryoglobulinemia; vasculitis; interferon-stimulated genes
Recently, several SNPs in the region of the IL28B (IFN-λ) gene have been associated with spontaneous clearance of hepatitis C virus (HCV) and enhanced cure rates for IFN-alfa-based therapies, suggesting a potential correlation between IFN-λ and the ability to clear HCV. To understand the mechanism of IFN-λ’s as compared to IFN-α’s antiviral activity, we performed a comprehensive analysis of their anti-HCV effects, whole genome transcriptome profiling with validation, and signaling of IFN-α and IFN-λ using J6/JFH-1 and Huh7.5 cells in vitro. IFN-λ and IFN-α exhibited comparable anti-HCV activity and gene expression profiles in Huh7.5 cells. While the majority of genes induced by IFN-α and IFN-λ were similar, IFN-λ exhibits profound, but delayed kinetics of ISG induction, while IFN-α induced more rapid induction of ISGs. Furthermore, the increased induction of ISG expression by IFN-λ correlated with up-regulation of IFN-λ receptor (IL-28RA) expression and more prolonged activation of the Jak-STAT signaling pathway. The findings from our comparative analysis of IFN-α and IFN-λ in HCV-infected and non-infected cells support the clinical use of IFN-λ as a potential alternative to IFN-α in the treatment of chronic hepatitis C.
Huh7.5 cells; hepatitis C; IFN-alpha; IL28B; JFH-1
HIV-induced immune activation leads to expansion of a subset of human CD8+ T cells expressing HLA-DR antigens. Expansion of CD8+HLA-DR+ T cells can be also observed in non-HIV settings including several autoimmune diseases and aging. Although these cells are felt to represent “immune exhaustion” and/or to be anergic, their precise role in host defense has remained unclear. Here, we report that this subset of cells exhibits a restricted repertoire, shows evidence of multiple rounds of division, but lacks markers of recent TCR-engagement. Detailed cell cycle analysis revealed that compared with their CD8+HLA-DR-counterpart, the CD8+HLA-DR+ T-cell pool contained an increased fraction of cells in S-phase with elevated levels of the G2/M regulators: cyclin A2, CDC25C, Cdc2 (CDK1), indicating that these cells are not truly anergic but rather experiencing proliferation in vivo. Together, these data support a hypothesis that antigen stimulation leads to the initial expansion of a CD8+ pool of cells in vivo that undergo further expansion independent of ongoing TCR-engagement. No qualitative differences were noted between CD8+HLA-DR+ cells from HIV+ and HIV− donors, indicating that the generation of CD8+HLA-DR+ T cells is a part of normal immune regulation that is exaggerated in the setting of HIV-1 infection.
Immune activation; HIV; activated CD8+ T cells; HLA-DR; cell cycle
PacBio RS, a newly emerging third-generation DNA sequencing platform, is based on a real-time, single-molecule, nano-nitch sequencing technology that can generate very long reads (up to 20-kb) in contrast to the shorter reads produced by the first and second generation sequencing technologies. As a new platform, it is important to assess the sequencing error rate, as well as the quality control (QC) parameters associated with the PacBio sequence data. In this study, a mixture of 10 prior known, closely related DNA amplicons were sequenced using the PacBio RS sequencing platform. After aligning Circular Consensus Sequence (CCS) reads derived from the above sequencing experiment to the known reference sequences, we found that the median error rate was 2.5% without read QC, and improved to 1.3% with an SVM based multi-parameter QC method. In addition, a De Novo assembly was used as a downstream application to evaluate the effects of different QC approaches. This benchmark study indicates that even though CCS reads are post error-corrected it is still necessary to perform appropriate QC on CCS reads in order to produce successful downstream bioinformatics analytical results.
PacBio; CCS read; quality control (QC); pass number; quality value (QV); SVM regression; assembly
IL-27 promotes the differentiation of monocytes to HIV-resistant macrophages by down-regulating host factor SPTBN1.
The susceptibility of macrophages to HIV-1 infection is modulated during monocyte differentiation. IL-27 is an anti-HIV cytokine that also modulates monocyte activation. In this study, we present new evidence that IL-27 promotes monocyte differentiation into macrophages that are nonpermissive for HIV-1 infection. Although IL-27 treatment does not affect expression of macrophage differentiation markers or macrophage biological functions, it confers HIV resistance by down-regulating spectrin β nonerythrocyte 1 (SPTBN1), a required host factor for HIV-1 infection. IL-27 down-regulates SPTBN1 through a TAK-1–mediated MAPK signaling pathway. Knockdown of SPTBN1 strongly inhibits HIV-1 infection of macrophages; conversely, overexpression of SPTBN1 markedly increases HIV susceptibility of IL-27–treated macrophages. Moreover, we demonstrate that SPTBN1 associates with HIV-1 gag proteins. Collectively, our results underscore the ability of IL-27 to protect macrophages from HIV-1 infection by down-regulating SPTBN1, thus indicating that SPTBN1 is an important host target to reduce HIV-1 replication in one major element of the viral reservoir.
Recent studies have shown that a single nucleotide polymorphism upstream of the interleukin (IL)-28B gene plays a major role in predicting therapeutic response in HCV-infected patients treated with pegylated interferon-alpha (IFN)/ribavirin. We sought to investigate the mechanism of the IL28B polymorphism, specifically as it relates to early HCV viral kinetics (VK), IFN pharmacokinetics (PK), IFN pharmacodynamics (PD), and gene expression profiles. Two prospective cohorts (HIV/HCV co-infected and HCV mono-infected) completing treatment with IFN/ribavirin were enrolled. Patients (N=88; 44 HIV/HCV and 44 HCV) were genotyped at the polymorphic site rs12979860. In the HIV/HCV cohort frequent serum sampling was completed for HCV RNA and IFN-levels. DNA microarray of PBMCs and individual expression of interferon stimulated genes (ISGs) were quantified on IFN-therapy. The IL28B favorable (CC) genotype was associated with improved therapeutic response compared to unfavorable (CT/TT) genotypes. Patients with favorable genotype had greater first and second phase VK (P=0.004 and P=0.036, respectively), IFN maximum anti-viral efficiency (P=0.007) and infected cell death loss (P=0.009) compared to unfavorable genotypes. Functional annotation analysis of DNA microarray data was consistent with depressed innate immune function, particularly of NK cells, from patients with unfavorable genotypes (P<0.004). Induction of innate immunity genes was also lower in unfavorable genotype. ISG expression at baseline and induction with IFN was independent of IL28B genotype.
Carriers of the IL28B favorable genotype were more likely to have superior innate immune response to IFN-therapy compared to unfavorable genotypes, this suggests the unfavorable genotype has aberrant baseline induction of innate immune response pathways resulting in impaired virologic response. IL28B genotype is associated with more rapid viral kinetics and improved treatment response outcomes independent of ISG expression.
Interferon Stimulating Genes; candidate gene; polymorphism; genetic variation
Cytosolic foreign DNA is detected by pattern recognition receptors and mainly induces Type-I IFN production. We found that transfection of different types of DNA into various untreated cells induces Type-III IFN (IFN-lambda1) rather than Type-I IFN, indicating the presence of uncharacterized DNA sensor(s). A pull-down assay using cytosolic proteins identified that Ku70 and Ku80 are the DNA binding proteins. The knockdown studies and the reporter assay revealed that Ku70 is a novel DNA sensor inducing the IFN-lambda1 activation. The functional analysis of IFNL1 promoter revealed that PRDI and ISRE sites are predominantly involved in the DNA-mediated IFNL1 activation. A pull-down assay using nuclear proteins demonstrated that the IFN-lambda1 induction is associated with the activation of IRF-1 and IRF-7. Thus we show for the first time that Ku70 mediates type III IFN induction by DNA.
Background. Although human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) affect mitochondrial DNA (mtDNA) content and function, comprehensive evaluations of their effects on mitochondria in muscle, adipose tissue, and blood cells are limited.
Methods. Mitochondrial DNA quantification, mitochondrial genome sequencing, and gene expression analysis were performed on muscle, adipose tissue, and peripheral blood mononuclear cell (PBMC) samples from untreated HIV-positive patients, HIV-positive patients receiving nucleoside reverse transcriptase inhibitor (NRTI)–based ART, and HIV-negative controls.
Results. The adipose tissue mtDNA/nuclear DNA (nDNA) ratio was increased in untreated HIV-infected patients (ratio, 353) and decreased in those receiving ART (ratio, 162) compared with controls (ratio, 255; P < .05 for both comparisons); the difference between the 2 HIV-infected groups was also significant (P = .002). In HIV-infected participants, mtDNA/nDNA in adipose tissue correlated with the level of activation (CD38+/HLA-DR+) for CD4+ and CD8+ lymphocytes. No significant differences in mtDNA content were noted in muscle or PMBCs among groups. Exploratory DNA microarray analysis identified differential gene expression between patient groups, including a subset of adipose tissue genes.
Conclusions. HIV infection and ART have opposing effects on mtDNA content in adipose tissue; immune activation may mediate the effects of HIV, whereas NRTIs likely mediate the effects of ART.
We investigated whether interferon-inducible genes (IFIGs) with known anti–human immunodeficiency virus (HIV) activity in vitro were associated with in vivo virological response in HIV infection. Nine untreated HIV-1–infected volunteers were treated for 12 weeks with peginterferon alfa-2a. A subset of IFIGs (23 of 47) increased compared with baseline through 6 weeks beyond therapy, and 10 of the 23 IFIGs significantly inversely correlated (r = −0.7; P < .05) with virological response. The strength of peginterferon alfa-2a–induced IFIG response significantly correlated with declines in HIV load during treatment (r2 = 0.87, p = .003). This study links HIV virological response to a specific IFIG subset, a potential prognostic indicator in peginterferon alfa-2a–treated patients with HIV infection.
IL-27, a member of the IL-12 family of cytokines, plays an important and diverse role in the function of the immune system. Whilst generally recognized as an anti-inflammatory cytokine, in addition IL-27 has been found to have broad anti-viral effects. Recently, IL-27 has been shown to be a potent inhibitor of HIV-1 infection in CD4+ T cells and macrophages. The main objective of this study was to see whether IL-27 has a similar inhibitory effect on HIV-1 replication in dendritic cells (DCs). Monocytes were differentiated into immature DCs (iDCs) and mature DCs (mDCs) with standard techniques using a combination of GM-CSF, IL-4 and LPS. Following differentiation, iDCs were infected with HIV-1 and co-cultured in the presence or absence of IL-27. IL-27 treated DCs were shown to be highly potent inhibitors of cis HIV-1, particularly of CCR5 tropic strains. Of note, other IL-12 family members (IL-12, IL-23 and IL-35) had no effect on HIV-1 replication. Microarray studies of IL-27 treated DCs showed no up-regulation of Type I (IFN) gene expression. Neutralization of the Type-I IFN receptor had no impact on the HIV inhibition. Lastly, IL-27 mediated inhibition was shown to act post-viral entry and prior to completion of reverse transcription. These results show for the first time that IL-27 is a potent inhibitor of cis HIV-1 infection in DCs by a Type I IFN independent mechanism. IL-27 has previously been reported to inhibit HIV-1 replication in CD4+ T cells and macrophages, thus taken together, this cytokine is a potent anti-HIV agent against all major cell types targeted by the HIV-1 virus and may have a therapeutic role in the future.
Hepatitis C-related fibrogenesis has been shown to involve complex interactions between peripheral and hepatic immune responses. Peripheral whole blood (PB) samples from patients with chronic hepatitis C (n = 36) were subjected to microarray analysis in order to identify gene expression patterns associated with immune pathways in PB and hepatic fibrosis. Distinct regulation of gene expression of inositol polyphosphate-5-phosphatase/145kDa (INPP5D or SHIP), a TLR2/TLR4-inhibitor, and heat shock protein 8/22kDa (HSPB8), an endogenous TLR4-ligand, during fibrogenesis was identified and could be confirmed by quantitative reverse-transcription polymerase chain reaction. These results suggest a potential link between peripheral activity of the TLR4-pathway, peripheral SHIP-dependent immune regulation, and liver fibrosis.
In order to develop targeted strategies for combating drug resistance it is essential to understand it’s basic molecular mechanisms. In an exploratory study we have found several possible indicators of etoposide resistance operating in MCF7VP cells, including up-regulation of ABC transporter genes, modulation of miRNA, and alteration in copy numbers of genes.
Retinoic acids regulate the reverse cholesterol transport by inducing the ATP binding cassette transporter A1 (ABCA1) dependent cholesterol efflux in macrophages, neuronal as well as intestine cells. In the present study, we aim to test the effect of all trans retinoic acid (ATRA) on ABCA1 expression in human CD4+ T cells and the involvement of cholesterol in ATRA mediated anti-HIV effect.
Treatment with ATRA dramatically up-regulated ABCA1 expression in CD4+ T cells in a time and dose dependent manner. The expression of ABCA1 paralleled with increased ABCA1-dependent cholesterol efflux. This induction was dependent on T cell receptor (TCR) signaling and ATRA failed to induce ABCA1 expression in resting T cells. Moreover, ATRA and liver X receptor (LXR) agonist-TO-901317 together had synergistic effect on ABCA1 expression as well as cholesterol efflux. Increased ABCA1 expression was associated with lower cellular cholesterol staining. Cells treated with either ATRA or TO-901317 were less vulnerable to HIV-1 infection. Combination of retinoic acid and TO-901317 further inhibited HIV-1 entry and their inhibitory effects could be reversed by cholesterol replenishment.
ABCA1 RNA and protein were determined by real-time PCR and immuno blot methods in cells treated with ATRA. Cholesterol efflux rate was measured in cells treated with ATRA and TO-901317.
ATRA up-regulates ABCA1 expression and cholesterol efflux in CD4+ T cells and combination of ATRA and liver X receptor (LXR) agonist further enhanced these effects. Increased cholesterol efflux contributed to reduced HIV-1 entry, suggesting that anti-HIV effect of ATRA is mediated through ABCA1.
ABCA1; ATRA; retinoic acid; TO-901317; RAR; RXR; LXR; cholesterol efflux; HIV-1; CD4+ T cells
In chronic hepatitis C virus (HCV) infection, liver tissue pathology and HCV genotype are important determinants of clinical and/or treatment-related outcome. Although consistent epidemiological and/or molecular-biological clues derived from different studies on single virus-host interactions are meanwhile published, the in vivo transcriptional responses and cellular pathways affected in >1 key aspects of the disease or treatment process are far from being understood.
Microarray analysis was performed in peripheral whole blood (PB) samples from 36 therapy-naïve HCV-infected patients with known liver histology. Linear regression analysis identified gene expression profiles significantly correlating (P < 0.015) with ≥1 out of 7 variables: sustained viral response (SVR), viral non-response (NR), end of treatment viral response (ETR), viral breakthrough (VB), HCV genotype (Gt. 1 vs. Gt. 2/3), stage of hepatic fibrosis [St. 0/1 vs. St. 2/3/4] and grade of hepatic inflammation (Gr. 0/1 vs. Gr. 2/3/4). Correlation values across all seven contrasts were considered for hierarchical clustering (HCL).
A total of 1,697 genes showed ≥1 significant correlation results and genes involved in cell differentiation (183), immune response (53), and apoptosis (170) were leading fractions. HCL grouped the genes into six major clusters. Functional annotation analysis using DAVID (http://david.abcc.ncifcrf.gov) revealed that expression profiles that best linked these variables were highly enriched in cytokine/chemokine activity (Fisher-exact P < 0.0001) and specific biological module-centric algorithms finally led our focus on four out of fifty-three immune response genes: SMAD family member 3 (SMAD3), interleukin 1 receptor accessory protein (IL1RAP), tumor necrosis factor receptor superfamily member 1A (TNFRSF1A), and chemokine ‘C-C motif’ receptor 5 (CCR5). Of those, TNFRSF1A and CCR5 showed significant correlation with two out of seven variables based on microarray and/or quantitative real-time polymerase chain reaction (qRT-PCR) data.
We identified molecular targets of the innate and adaptive immune system and validated their transcriptional specificity in vivo suggesting significant involvement in two unique outcomes during HCV treatment.
HCV; Cytokines; Chemokines; Microarrays
Summary: The database for annotation, visualization and integrated discovery (DAVID), which can be freely accessed at http://david.abcc.ncifcrf.gov/, is a web-based online bioinformatics resource that aims to provide tools for the functional interpretation of large lists of genes/proteins. It has been used by researchers from more than 5000 institutes worldwide, with a daily submission rate of ∼1200 gene lists from ∼400 unique researchers, and has been cited by more than 6000 scientific publications. However, the current web interface does not support programmatic access to DAVID, and the uniform resource locator (URL)-based application programming interface (API) has a limit on URL size and is stateless in nature as it uses URL request and response messages to communicate with the server, without keeping any state-related details. DAVID-WS (web service) has been developed to automate user tasks by providing stateful web services to access DAVID programmatically without the need for human interactions.
Availability: The web service and sample clients (written in Java, Perl, Python and Matlab) are made freely available under the DAVID License at http://david.abcc.ncifcrf.gov/content.jsp?file=WS.html.
We previously reported the establishment of a rabbit (Oryctolagus cuniculus) model in which peptide immunization led to production of lupus-like autoantibodies including anti-Sm, -RNP, -SS-A, -SS-B and –dsDNA characteristic of those produced in Systemic Lupus Erythematosus (SLE) patients. Some neurological symptoms in form of seizures and nystagmus were observed. The animals used in the previous and in the present study were from a National Institute of Allergy and Infectious Diseases colony of rabbits that were pedigreed, immunoglobulin allotype-defined but not inbred. Their genetic heterogeneity may correspond to that found among patients of a given ethnicity. We extended the information about this rabbit model by microarray based expression profiling. We first demonstrated that human expression arrays could be used with rabbit RNA to yield information on molecular pathways. We then designed a study evaluating gene expression profiles in 8 groups of control and treated rabbits (47 rabbits in total). Genes significantly upregulated in treated rabbits were associated with NK cytotoxicity, antigen presentation, leukocyte migration, cytokine activity, protein kinases, RNA spliceosomal ribonucleoproteins, intracellular signaling cascades, and glutamate receptor activity. These results link increased immune activation with up-regulation of components associated with neurological and anti-RNP responses, demonstrating the utility of the rabbit model to uncover biological pathways related to SLE-induced clinical symptoms, including Neuropsychiatric Lupus. Our finding of distinct gene expression patterns in rabbits that made anti-dsDNA compared to those that only made other anti-nuclear antibodies should be further investigated in subsets of SLE patients with different autoantibody profiles.
It is known that retinoid receptor function is attenuated during T cell activation, a phenomenon that involves actin remodeling, suggesting that actin modification may play a role in such inhibition. Here we have investigated the role of actin dynamics and the effect of actin cytoskeleton modifying agents on retinoid receptor-mediated transactivation.
Agents that disturb the F-actin assembly or disassembly attenuated receptor-mediated transcription indicating that actin cytoskeletal homeostasis is important for retinoid receptor function. Overexpression or siRNA-induced knockdown of cofilin-1 (CFL1), a key regulator of F-actin assembly, induced the loss of receptor function. In addition, expression of either constitutively active or inactive/dominant-negative mutants of CFL1or CFL1 kinase LIMK1 induced loss of receptor function suggesting a critical role of the LIMK1-mediated CFL1 pathway in receptor-dependent transcription. Further evidence of the role of LMK1/CFL1-mediated actin dynamics, was provided by studying the effect of Nef, an actin modifying HIV-1 protein, on receptor function. Expression of Nef induced phosphorylation of CFL1 at serine 3 and LIMK1 at threonine 508, inhibited retinoid-receptor mediated reporter activity, and the expression of a number of genes that contain retinoid receptor binding sites in their promoters. The results suggest that the Nef-mediated inhibition of receptor function encompasses deregulation of actin filament dynamics by LIMK1 activation and phosphorylation of CFL1.
We have identified a critical role of LIMK1-mediated CFL1 pathway and actin dynamics in modulating retinoid receptor mediated function and shown that LIMK1-mediated phosphocycling of CFL1 plays a crucial role in maintaining actin homeostasis and receptor activity. We suggest that T cell activation-induced repression of nuclear receptor-dependent transactivation is in part through the modification of actin dynamics.
The antiviral activity of pegylated interferon-alpha-2a has not been studied in untreated HIV-1-infected subjects without chronic hepatitis C virus (HCV) infection.
Untreated HIV-1-infected volunteers without HCV received weekly pegylated interferon alfa-2a (180 μg) for twelve weeks. Changes in HIV-1 RNA (pVL), CD4+ T-cell counts, pharmacokinetics, pharmacodynamic measurements of 2’,5’ oligoadenylate synthetase (OAS) activity, and induction of interferon inducible genes (IFIG) were measured. Nonparametric statistical analysis was performed.
Eleven subjects completed 12 weeks of therapy. Median pVL decline and change in CD4 T-cell counts at week 12 were 0.61 log10 cp/mL [90% CI:0.20,1.18] and −44 (− 95, 85) cells/mm3, respectively. There was no correlation between pVL declines and concurrent pegylated interferon plasma concentrations. However, subjects with larger increases in OAS exhibited greater decreases in pVL at weeks 1 and 2 (estimated Spearman correlations -0.75 [-0.93,-0.28]) and -0.61 [-0.87,-0.09], respectively). Subjects with higher baseline IFIG levels had smaller week 12 declines in pVL (0.66[0.06,0.91]), while those with larger IFIG induction exhibited larger declines in pVL (-0.74 [-0.93,-0.21]).
Pegylated interferon alfa-2a was well tolerated and had significant anti-HIV-1 activity in HIV-1-monoinfected patients. The anti-HIV-1 effect correlated with OAS protein (weeks 1 and 2) and IFIG induction (week 12), but not with pegylated interferon concentrations.
mRNA expression signatures are frequently used as surrogate measures of cellular function and pathway changes. Few studies have directly compared results obtained using gene expression and multiplex protein assays for corresponding gene products.
We utilized data available from a clinical trial of an HPV-16 vaccine that tracked gene expression and cytokine/chemokine production by peripheral blood mononuclear cells (PBMCs) stimulated in culture with various antigens to evaluate the degree to which gene expression levels reflect observed levels of cytokines/chemokines. Twenty-six women enrolled in a phase II clinical trial of an HPV-16 vaccine were evaluated for gene expression (using the Affymetrix Human Genome Focus Array) and cytokine/chemokine levels (using a bead-based 22-plex cytokine assay developed by Linco Research, Inc.) before and after vaccination.
Our results suggest the presence of a wide range of correlations between mRNA expression and secreted protein levels. The strongest correlation was observed for IFN-γ (R=0.90 overall levels; 0.69 when vaccine induced changes were evaluated). More modest overall correlations ranging from 0.40 to 0.80 were observed for MIP1A, IP10, TNF-α, MCP1, IL2, GM-CSF, IL5, RANTES, and IL-8. Weaker or no correlation was observed between gene expression and protein levels for the remaining cytokines/chemokines evaluated.
The degree of correlation between gene expression and protein levels varied among different cytokines/chemokines.
Researchers should be cautious when using mRNA expression array results as a proxy for protein levels using existing technologies.
cytokines; mRNA expression; protein levels; affymetrix gene expression microarray; multiplex protein assays
Gene duplication is a normal evolutionary process. If there is no selective advantage in keeping the duplicated gene, it is usually reduced to a pseudogene and disappears from the genome. However, some paralogs are retained. These gene products are likely to be beneficial to the organism, e.g. in adaptation to new environmental conditions. The aim of our analysis is to investigate the properties of paralog-forming genes in prokaryotes, and to analyse the role of these retained paralogs by relating gene properties to life style of the corresponding prokaryotes.
Paralogs were identified in a number of prokaryotes, and these paralogs were compared to singletons of persistent orthologs based on functional classification. This showed that the paralogs were associated with for example energy production, cell motility, ion transport, and defence mechanisms. A statistical overrepresentation analysis of gene and protein annotations was based on paralogs of the 200 prokaryotes with the highest fraction of paralog-forming genes. Biclustering of overrepresented gene ontology terms versus species was used to identify clusters of properties associated with clusters of species. The clusters were classified using similarity scores on properties and species to identify interesting clusters, and a subset of clusters were analysed by comparison to literature data. This analysis showed that paralogs often are associated with properties that are important for survival and proliferation of the specific organisms. This includes processes like ion transport, locomotion, chemotaxis and photosynthesis. However, the analysis also showed that the gene ontology terms sometimes were too general, imprecise or even misleading for automatic analysis.
Properties described by gene ontology terms identified in the overrepresentation analysis are often consistent with individual prokaryote lifestyles and are likely to give a competitive advantage to the organism. Paralogs and singletons dominate different categories of functional classification, where paralogs in particular seem to be associated with processes involving interaction with the environment.
Many species form extraembryonic tissues during embryogenesis, such as the placenta of humans and other viviparous mammals. Extraembryonic tissues have various roles in protecting, nourishing and patterning embryos. Prior to gastrulation in zebrafish, the yolk syncytial layer - an extraembryonic nuclear syncytium - produces signals that induce mesoderm and endoderm formation. Mesoderm and endoderm precursor cells are situated in the embryonic margin, an external ring of cells along the embryo-yolk interface. The yolk syncytial layer initially forms below the margin, in a domain called the external yolk syncytial layer (E-YSL).
We hypothesize that key components of the yolk syncytial layer's mesoderm and endoderm inducing activity are expressed as mRNAs in the E-YSL. To identify genes expressed in the E-YSL, we used microarrays to compare the transcription profiles of intact pre-gastrula embryos with pre-gastrula embryonic cells that we had separated from the yolk and yolk syncytial layer. This identified a cohort of genes with enriched expression in intact embryos. Here we describe our whole mount in situ hybridization analysis of sixty-eight of them. This includes ten genes with E-YSL expression (camsap1l1, gata3, znf503, hnf1ba, slc26a1, slc40a1, gata6, gpr137bb, otop1 and cebpa), four genes with expression in the enveloping layer (EVL), a superficial epithelium that protects the embryo (zgc:136817, zgc:152778, slc14a2 and elovl6l), three EVL genes whose expression is transiently confined to the animal pole (elovl6l, zgc:136359 and clica), and six genes with transient maternal expression (mtf1, wu:fj59f04, mospd2, rftn2, arrdc1a and pho). We also assessed the requirement of Nodal signaling for the expression of selected genes in the E-YSL, EVL and margin. Margin expression was Nodal dependent for all genes we tested, including the concentrated margin expression of an EVL gene: zgc:110712. All other instances of EVL and E-YSL expression that we tested were Nodal independent.
We have devised an effective strategy for enriching and identifying genes expressed in the E-YSL of pre-gastrula embryos. To our surprise, maternal genes and genes expressed in the EVL were also enriched by this strategy. A number of these genes are promising candidates for future functional studies on early embryonic patterning.