Genotype-related variations in proinflammatory and regulatory cytokine levels in treated and treatment-naive HCV-infected patients.

Hepatitis C virus (HCV) modulates immune-related inflammatory responses to induce milder reactions leading to virus persistence. In this regard, the present study aimed to investigate the link between the HCV genotypes and the proinflammatory and regulatory cytokine levels. Ninety patients with hepatitis C infection (68 treatment-naive and 22 treated patients) and 76 healthy blood donors were studied. The serum levels of IFN-γ, IL-10, IL-17A, and IL-21 were measured by ELISA in the patients and healthy controls. IL-10, IL-17A, and IL-21 levels were significantly higher in HCV patients than in the healthy controls. The same cytokines were also higher in genotype 3a-infected patients compared with genotype 1a-infected patients. Interestingly, in treated patients, lower serum levels of IL-17A and IL-21 were detected in G3a-infected individuals, but not in those infected with G1a. G3a viral load displayed a significant correlation with IL-21 and IL-17A levels. In addition, G1a viral load correlated with IL-10 levels. In G3a-infected patients, a significant association was found between IL-17A serum levels and ALT. We found differences in IL-21 and IL-17A serum levels among HCV-infected patients which were genotype dependent. Since Th17-associated cytokines are associated with the progression of liver disease in HCV patients, IL-17A and IL-21 can be used as important biological markers for evaluating the immunopathogenesis of chronic hepatitis. Our results suggest that HCV G3a along with immune responses such as cytokines in HCV patients should be taken into account when interpreting clinical data and IFN-based therapeutic response.

HIV-1 Vpr Protein Induces Proteasomal Degradation of Chromatin-associated Class I HDACs to Overcome Latent Infection of Macrophages.

Mechanisms underlying HIV-1 latency remain among the most crucial questions that need to be answered to adopt strategies for purging the latent viral reservoirs. Here we show that HIV-1 accessory protein Vpr induces depletion of class I HDACs, including HDAC1, 2, 3, and 8, to overcome latency in macrophages. We found that Vpr binds and depletes chromatin-associated class I HDACs through a VprBP-dependent mechanism, with HDAC3 as the most affected class I HDAC. De novo expression of Vpr in infected macrophages induced depletion of HDAC1 and 3 on the HIV-1 LTR that was associated with hyperacetylation of histones on the HIV-1 LTR. As a result of hyperacetylation of histones on HIV-1 promotor, the virus established an active promotor and this contributed to the acute infection of macrophages. Collectively, HIV-1 Vpr down-regulates class I HDACs on chromatin to counteract latent infections of macrophages.

Underlying mechanisms of HIV-1 latency.

Similarly to other retroviruses, HIV-1 integrates its genome into the cellular chromosome. Expression of viral genes from the integrated viral DNA could then be regulated by the host genome. If the infected cell suppresses viral gene expression, the virus will undergo latency. The latently infected cells cannot be detected or cleared by the immune system since they do not express viral antigens. These cells remain undetected for several years, even under antiretroviral treatments. The silenced HIV-1 DNA could be reactivated under certain conditions. Despite the efficient use of antiretroviral drugs, HIV-1 latently infected cells remain the major obstacles to a permanent cure. In this review, we discuss the cellular and molecular mechanisms through which HIV-1 establishes latency.

HIV-1 Vpr Protein Enhances Proteasomal Degradation of MCM10 DNA Replication Factor through the Cul4-DDB1[VprBP] E3 Ubiquitin Ligase to Induce G2/M Cell Cycle Arrest.

Human immunodeficiency virus type 1 Vpr is an accessory protein that induces G2/M cell cycle arrest. It is well documented that interaction of Vpr with the Cul4-DDB1[VprBP] E3 ubiquitin ligase is essential for the induction of G2/M arrest. In this study, we show that HIV-1 Vpr indirectly binds MCM10, a eukaryotic DNA replication factor, in a Vpr-binding protein (VprBP) (VprBP)-dependent manner. Binding of Vpr to MCM10 enhanced ubiquitination and proteasomal degradation of MCM10. G2/M-defective mutants of Vpr were not able to deplete MCM10, and we show that Vpr-induced depletion of MCM10 is related to the ability of Vpr to induce G2/M arrest. Our study demonstrates that MCM10 is the natural substrate of the Cul4-DDB1[VprBP] E3 ubiquitin ligase whose degradation is regulated by VprBP, but Vpr enhances the proteasomal degradation of MCM10 by interacting with VprBP.

Functions of Tat: the versatile protein of human immunodeficiency virus type 1.

Human immunodeficiency virus type 1 (HIV-1) Tat is a multifunctional protein that contributes to several pathological symptoms of HIV-1 infection as well as playing a critical role in virus replication. Tat is a robust transactivating protein that induces a variety of effects by altering the expression levels of cellular and viral genes. The functions of Tat are therefore primarily related to its role in modulation of gene expression. In this review the functions of HIV-1 Tat that have been well documented, as well as a number of novel functions that have been proposed for this protein, are discussed. Since some of the functions of Tat vary in different cell types in a concentration-dependent manner and because Tat sometimes exerts the same activity through different pathways, study of this protein has at times yielded conflicting and controversial results. Due to its pivotal role in viral replication and in disease pathogenesis, Tat and the cellular pathways targeted by Tat are potential targets for new anti-HIV drugs.

Antiviral roles of APOBEC proteins against HIV-1 and suppression by Vif.

Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like (APOBEC) proteins are members of a protein family sharing the common characteristic of cytidine deaminase activity. The antiviral activity of APOBEC3G and APOBEC3F has been studied more extensively than that of the other members of this family. The antiviral activity of APOBEC3B and APOBEC3DE has also been described. Studies of other APOBEC proteins have not revealed any antiviral activities against HIV-1; however, further investigation is required. In the absence of human immunodeficiency virus type 1 (HIV-1) virion infectivity factor (Vif), APOBEC3G and APOBEC3F are incorporated into HIV-1 virions and hypermutate the viral genomic DNA by their cytidine deaminase activity. HIV-1 Vif protein suppresses the antiviral role of APOBEC proteins by several mechanisms that lead to inhibition of incorporation of APOBEC3G/3F into HIV-1 virions. The detailed mechanisms involved in the suppression of APOBEC proteins by Vif are still being elucidated. Novel studies in which as yet undefined aspects of the suppression of APOBEC proteins are investigated could reveal important and potentially exploitable information for addressing HIV-1 infection in humans.

Erratum: Functional conservation and coherence of HIV-1 subtype A Vpu alleles.

This corrects the article DOI: 10.1038/srep44894.

Functional conservation and coherence of HIV-1 subtype A Vpu alleles.

Functional studies of HIV-1 proteins are normally conducted using lab adapted strains of HIV-1. The extent of those functions in clinical strains is sometimes unknown. In this study, we amplified and sequenced HIV-1 Vpu from 10 Iranian patients infected with HIV-1. Phylogenetic analysis indicated that the Vpu alleles were closely related to the CRF35_AD from Iran and subtype A Vpu. We addressed some of the well-established functions of the HIV-1 Vpu, as well as some of its recently reported functions. Ability of the clinical strains of subtype A Vpu alleles for downregulation of CD4 was similar to that of the lab adapted NL4.3 Vpu. Majority of the subtype A Vpu alleles performed stronger than NL4.3 Vpu for downregulation of SNAT1. The Vpu alleles differentially induced downregulation of HLA-C, ranging from no effect to 88% downregulation of surface HLA-C. Downregulation of tetherin and enhancement of virus release was similar for the subtype A Vpu alleles and NL4.3. Subtype A Vpu alleles were more potent when compared with NL4.3 for inhibition of NF-κB activation. Our study shows that subtype A Vpu alleles exert the classical functions of HIV-1 Vpu.

Functional conservation and coherence of HIV-1 subtype A Vpu alleles.

Functional studies of HIV-1 proteins are normally conducted using lab adapted strains of HIV-1. The extent of those functions in clinical strains is sometimes unknown. In this study, we amplified and sequenced HIV-1 Vpu from 10 Iranian patients infected with HIV-1. Phylogenetic analysis indicated that the Vpu alleles were closely related to the CRF35_AD from Iran and subtype A Vpu. We addressed some of the well-established functions of the HIV-1 Vpu, as well as some of its recently reported functions. Ability of the clinical strains of subtype A Vpu alleles for downregulation of CD4 was similar to that of the lab adapted NL4.3 Vpu. Majority of the subtype A Vpu alleles performed stronger than NL4.3 Vpu for downregulation of SNAT1. The Vpu alleles differentially induced downregulation of HLA-C, ranging from no effect to 88% downregulation of surface HLA-C. Downregulation of tetherin and enhancement of virus release was similar for the subtype A Vpu alleles and NL4.3. Subtype A Vpu alleles were more potent when compared with NL4.3 for inhibition of NF-κB activation. Our study shows that subtype A Vpu alleles exert the classical functions of HIV-1 Vpu.

Antibody production by in vivo RNA transfection.

Monoclonal antibodies have a variety of applications in research and medicine. Here, we report development of a new method for production of monoclonal antibodies. Our method relies on in vivo RNA transfection rather than peptide vaccination. We took advantage of RNA transcripts complexed with DOTMA and DOPE lipids to transfect mice. Intravenous administration of our RNA vaccine to mice resulted in expression of the antigenic peptides by splenic dendritic cells and detection of the antigens in the serum. The RNA vaccine stimulated production of specific antibodies against the RNA-encoded peptides. We produced monoclonal antibodies against viral, bacterial, and human antigens. In addition, we showed that our RNA vaccine stimulated humoral immunity and rescued mice infected with influenza A virus. Our method could be used as an efficient tool to generate monoclonal antibodies and to stimulate humoral immunity for research and medical purposes.

Antimicrobial activity of endophytic bacterial populations isolated from medical plants of Iran.

BACKGROUND AND OBJECTIVES: Endophytic actinobacteria colonize inside the plant tissues without causing damages to the host plant. Since these microorganisms colonize in the different parts of plants and can stop plant disease, they have been applied as biological agents for controlling human diseases. The aim of this study was molecular identification and measuring the antimicrobial activity of endophytic Actinomycetes isolated from medicinal plants of Iran. MATERIALS AND METHODS: The total of 23 medicinal plant samples were collected, sterilized, and crushed. Small pieces of the crushed samples were then cultured directly on three selective media. Grown colonies were identified by 16S rRNA gene sequencing method. Each isolate was cultured in TSB medium and then antimicrobial compound was extracted using ethyl acetate and tested against the target bacteria. RESULTS: Sixteen out of 23 bacterial isolates (69%) exhibited antimicrobial activity against the selected pathogenic bacteria, such as Bacillus cereus, Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumoniae, Citrobacter freundii, Proteus mirabilis, Shigella flexneri and Escherichia coli. CONCLUSION: Our Study showed a high phylogenetic diversity and the potent antibiotic activity of endophytic bacteria in medicinal plants of Iran.

Targeting human breast cancer cells by an oncolytic adenovirus using microRNA-targeting strategy.

MicroRNA-targeting strategy is a promising approach that enables oncolytic viruses to replicate in tumor cells but not in normal cells. In this study, we targeted adenoviral replication toward breast cancer cells by inserting ten complementary binding sites for miR-145-5p downstream of E1A gene. In addition, we evaluated the effect of increasing miR-145 binding sites on inhibition of virus replication. Ad5-control and adenoviruses carrying five or ten copies of miR145-5p target sites (Ad5-5miR145T, Ad5-10miR145T) were generated and inoculated into MDA-MB-453, BT-20, MCF-7 breast cancer cell lines and human mammary epithelial cells (HMEpC). Titer of Ad5-10miR145T in HMEpC was significantly lower than Ad5-control titer. Difference between the titer of these two viruses at 12, 24, 36, and 48h after infection was 1.25, 2.96, 3.06, and 3.77 log TCID50. No significant difference was observed between the titer of both adenoviruses in MDA-MB-453, BT-20 and MCF-7 cells. The infectious titer of adenovirus containing 10 miR-145 binding sites in HMEpC cells at 24, 36, and 48h post-infection was 1.7, 2.08, and 4-fold, respectively, lower than the titer of adenovirus carrying 5 miR-145 targets. Our results suggest that miR-145-targeting strategy provides selectivity for adenovirus replication in breast cancer cells. Increasing the number of miRNA binding sites within the adenoviral genome confers more selectivity for viral replication in cancer cells.

The Effect of Various Stabilizers on Preserving Immunogenicity of Lyophilized Mumps Vaccines.

BACKGROUND: Chemical stabilizers are added to live attenuated vaccines for enhancing the virus stability. The aim of this study was to evaluate the effect of various stabilizers on preserving immunogenicity of lyophilized mumps vaccines. STUDY DESIGN: An experimental study. METHODS: Three mumps vaccines with different formulations were inoculated to three groups of Guinea pigs. Sterile water was injected to eight Guinea pigs as a control group. Blood samples were collected before inoculation and on 14, 28 and 42 d after vaccine injection. Mumps antibodies in the sera were measured using hemagglutination inhibition assay (HAI). RESULTS: All three formulated mumps vaccines induced antibody in Guinea pigs after two weeks. Formulation 1 containing trehalose dihydrate and formulation 2 comprised human serum albumin stimulated antibodies in the higher level than Razi routine formulation. CONCLUSIONS: Various stabilizers have different preservation potencies that differently affect immune response against virus. More stable and more immunogenic vaccines can be produced using stabilizers containing trehalose dihydrate.

Autophagy induction reduces telomerase activity in HeLa cells.

Autophagy is a cellular homeostatic process whereby damaged proteins and organelles are encapsulated into double membrane vesicles, called autophagosomes, for lysosomal digestion. Beclin1 plays a key role in the initial steps of autophagosome formation. In this study, we evaluated the effect of Beclin 1 overexpression in induction of autophagy and the relationship between autophagy induction and telomerase activity in HeLa cells. We found that overexpression of Beclin 1 in HeLa cells leads to autophagosome formation as shown by intracellular autophagosomal marker LC3-II staining. Expression of Beclin1 reduced telomerase activity for about 100 fold compared with the control while it did not affect TERT expression level. The results of cell cycle analysis indicated that the cell cycle and proliferation progressed normally up to 48h post-transfection. Understanding the role of autophagy induction and telomerase in the pathophysiology of aging and human cancer reveal new strategies that hold much promise for intervention and therapeutic uses.

No genetic association between A118G polymorphism of µ-opioid receptor gene and schizophrenia and bipolar disorders.

BACKGROUND: Schizophrenia (SZ) and bipolar disorder (BD) are chronic and multifactorial psychiatric disorders that might be affected by different genes in combination with environmental factors. There is evidence of association between polymorphisms of µ-opioid receptor gene (OPRM1) with these disorders. OBJECTIVES: The aim of this study was to investigate the genetic association between OPRM1 A118G SNP in SZ and BD patients in comparison with healthy controls (HCs). MATERIALS AND METHODS: One single-nucleotide polymorphism in OPRM1 was genotyped using TaqMan real-time PCR assay in 203 SZ and BD patients and 389 HCs. RESULTS: There was no statistically significant difference in genotypic and allelic frequencies of OPRM1 A118G SNP between HCs and SZ/BD patients. CONCLUSIONS: To find the underlying genetic factors associated with these complex disorders, further studies need to be conducted using larger sample size, different genetic populations, and different gene variations.

Autophagy induction regulates influenza virus replication in a time-dependent manner.

PURPOSE: Autophagy plays a key role in host defence responses against microbial infections by promoting degradation of pathogens and participating in acquired immunity. The interaction between autophagy and viruses is complex, and this pathway is hijacked by several viruses. Influenza virus (IV) interferes with autophagy through its replication and increases the accumulation of autophagosomes by blocking lysosome fusion. Thus, autophagy could be an effective area for antiviral research. METHODOLOGY: In this study, we evaluated the effect of autophagy on IV replication. Two cell lines were transfected with Beclin-1 expression plasmid before (prophylactic approach) and after (therapeutic approach) IV inoculation.Results/Key findings. Beclin-1 overexpression in the cells infected by virus induced autophagy to 26 %. The log10haemagglutinin titre and TCID50 (tissue culture infective dose giving 50 % infection) of replicating virus were measured at 24 and 48 h post-infection. In the prophylactic approach, the virus titre was enhanced significantly at 24 h post-infection (P≤0.01), but it was not significantly different from the control at 48 h post-infection. In contrast, the therapeutic approach of autophagy induction inhibited the virus replication at 24 and 48 h post-infection. Additionally, we showed that inhibition of autophagy using 3-methyladenine reduced viral replication. CONCLUSION: This study revealed that the virus (H1N1) titre was controlled in a time-dependent manner following autophagy induction in host cells. Manipulation of autophagy during the IV life cycle can be targeted both for antiviral aims and for increasing viral yield for virus production.

HIV-1 Vpr reactivates latent HIV-1 provirus by inducing depletion of class I HDACs on chromatin.

HIV-1 Vpr is an accessory protein that induces proteasomal degradation of multiple proteins. We recently showed that Vpr targets class I HDACs on chromatin for proteasomal degradation. Here we show that Vpr induces degradation of HDAC1 and HDAC3 in HIV-1 latently infected J-Lat cells. Degradation of HDAC1 and HDAC3 was also observed on the HIV-1 LTR and as a result, markers of active transcription were recruited to the viral promoter and induced viral activation. Knockdown of HDAC1 and HDAC3 activated the latent HIV-1 provirus and complementation with HDAC3 inhibited Vpr-induced HIV-1 reactivation. Viral reactivation and degradation of HDAC1 and HDAC3 was conserved among Vpr proteins of HV-1 group M. Serum Vpr isolated from patients or the release of virion-incorporated Vpr from viral lysates also activated HIV-1 in latently infected cell lines and PBMCs from HIV-1 infected patients. Our results indicate that Vpr counteracts HIV-1 latency by inducing proteasomal degradation of HDAC1 and 3 leading to reactivation of the viral promoter.

Defining the interactions and role of DCAF1/VPRBP in the DDB1-cullin4A E3 ubiquitin ligase complex engaged by HIV-1 Vpr to induce a G2 cell cycle arrest.

HIV viral protein R (Vpr) induces a cell cycle arrest at the G2/M phase by activating the ATR DNA damage/replication stress signalling pathway through engagement of the DDB1-CUL4A-DCAF1 E3 ubiquitin ligase via a direct binding to the substrate specificity receptor DCAF1. Since no high resolution structures of the DDB1-DCAF1-Vpr substrate recognition module currently exist, we used a mutagenesis approach to better define motifs in DCAF1 that are crucial for Vpr and DDB1 binding. Herein, we show that the minimal domain of DCAF1 that retained the ability to bind Vpr and DDB1 was mapped to residues 1041 to 1393 (DCAF1 WD). Mutagenic analyses identified an α-helical H-box motif and F/YxxF/Y motifs located in the N-terminal domain of DCAF1 WD that are involved in exclusive binding to DDB1. While we could not identify elements specifically involved in Vpr binding, overall, the mutagenesis data suggest that the predicted ß-propeller conformation of DCAF1 is likely to be critical for Vpr association. Importantly, we provide evidence that binding of Vpr to DCAF1 appears to modulate the formation of a DDB1/DCAF1 complex. Lastly, we show that expression of DCAF1 WD in the absence of endogenous DCAF1 was not sufficient to enable Vpr-mediated G2 arrest activity. Overall, our results reveal that Vpr and DDB1 binding on DCAF1 can be genetically separated and further suggest that DCAF1 contains determinants in addition to the Vpr and DDB1 minimal binding domain, which are required for Vpr to enable the induction of a G2 arrest.

Lentivirus Vpr and Vpx accessory proteins usurp the cullin4-DDB1 (DCAF1) E3 ubiquitin ligase.

Myeloid cells display a differential permissivity to primate lentivirus infection that is related to their ability to encode the Vpx and to a lesser extent the Vpr accessory proteins. Vpr is encoded by all primate lentiviruses, including HIV-1 and HIV-2, while its paralog, Vpx, is unique to HIV-2 and a subset of simian lentiviruses. Both proteins usurp the CRL4A (DCAF1) E3 ligase to fulfil their functions. Vpx induces the degradation of SAMHD1, a nucleotide triphosphohydrolase that blocks lentiviral reverse transcription in myeloid cells via depletion of the intracellular pool of dNTPs. Vpr engages CRL4A (DCAF1) to degrade a yet unknown factor(s), whose proteolysis induces a G2 cell-cycle arrest in dividing cells. Although the identification of the host protein(s) targeted for degradation by Vpr will be necessary to understand its actual function, the discovery of SAMHD1 has already shed light into a new mechanism of restriction that limits infection of myeloid cells by HIV-1.

Functional integrity of naturally occurring mutants of HIV-1 subtype C Vpr.

HIV-1 Vpr, an accessory protein with multiple functions, is involved in the induction of apoptosis, cell cycle G2 arrest, and modulation of gene expression. Many functions of this protein have been documented for the wild-type subtype B Vpr, however the functionality of other subtypes has not sufficiently been addressed. In this study, the functionality of Subtype B Vpr, 6 subtype C mutant Vpr proteins and the consensus sequence of subtype C Vpr were compared with each other. All the subtype B and C Vpr proteins localized to the nucleus of human 293T cells. Subtype C Vpr proteins induced cell cycle G2 arrest in a lower proportion of human 293T cells compared to subtype B Vpr. Subtype B and the naturally mutant Vpr proteins induced apoptosis in a similar manner, ranging from 95.33% to 98.64%. However, an artificially designed Vpr protein containing the consensus sequences of subtype C Vpr indicated a reduced ability in induction of apoptosis. The study of mRNA profile of the transfected cells indicated that all Vpr proteins modulated the apoptotic genes triggering the intrinsic pathway of apoptosis. Our results indicate that subtype C Vpr is able to exert the same functions previously reported for subtype B Vpr. Most natural mutations in Vpr not only do not disturb the functions of the protein but also potentiate the protein for an increased functionality. The natural mutations of Vpr may thus not always be regarded as defective mutations. The study suggests the adaptive role of the natural mutations commonly found in subtype C Vpr.