MicroRNA regulation of viral immunity, latency, and carcinogenesis of selected tumor viruses and HIV

Immune Characteristics and Immunotherapy of HIV-Associated Lymphoma

In the era of antiretroviral therapy (ART), mortality among people living with the human immunodeficiency virus (HIV) has significantly decreased, yet the population of people living with HIV remains substantial. Among people living with HIV (PLWH), HIV-associated lymphoma (HAL) has surpassed Kaposi's sarcoma to become the most common tumor in this population in developed countries. However, there remains a dearth of comprehensive and systematic understanding regarding HIV-associated lymphomas. This review aims to shed light on the changes in the immune system among PLWH and the characteristics of the immune microenvironment in HIV-associated lymphoma, with a specific focus on the immune system's role in these individuals. Additionally, it seeks to explore recent advancements in immunotherapy for the treatment of HIV-associated lymphoma, intending to enhance strategies for immunotherapy in this specific population.

Study on anti-BmNPV mechanism of branched-chain amino acid aminotransferases in silkworm

Bombyx mori nucleopolyhedrovirus (BmNPV) is the most important virus that threatens sericulture industry. At present, there is no effective treatment for BmNPV infection in silkworms, and lncRNA plays an important role in biological immune response and host-virus interaction, but there are relatively few studies in silkworms. In this study, the four midgut tissue samples of the resistance strain NB (NB) and susceptible strain 306 (306) and the NB and 306 continuously infected with BmNPV for 96 h are used for whole transcriptome sequencing to analyze the differences in the genetic background of NB and 306 and the differences after inoculation of BmNPV, and the significantly different mRNA, miRNA and lnRNA between NB and 306 after BmNPV inoculation were screened. By comparing NB and 306, 2651 significantly different mRNAs, 57 significantly different miRNAs and 198 significantly different lncRNAs were screened. By comparing NB and 306 after BmNPV inoculation, 2684 significantly different mRNAs, 39 significantly different miRNAs and 125 significantly different lncRNAs were screened. According to the significantly different mRNA, miRNA and lncRNA screened from NB and 306 and NB and 306 after virus inoculation, the mRNA-miRNA-lncRNA regulatory network was constructed before and after virus inoculation, and the BmBCAT-Bomo_chr7_8305-MSTRG.3236.2 regulatory axis was screened from them, and it was found that BmBCAT was not Bomo_chr7_8305 regulated in the genetic background, after viral infection, MSTRG.3236.2 competes for binding Bomo_chr7_8305 regulates BmBCAT. The whole transcriptome sequencing results were verified by qPCR and the time-series expression analysis was performed to prove the reliability of the regulatory network. The BmBCAT-Bomo_chr7_8305-MSTRG.3236.2 regulatory axis may play a potential role in the interaction between silkworms and BmNPV. These results provide new insights into the interaction mechanism between silkworms and BmNPV.

Insights into intricacies of the Latent Membrane Protein-1 (LMP-1) in EBV-associated cancers

Numerous lymphomas, carcinomas, and other disorders have been associated with Epstein-Barr Virus (EBV) infection. EBV's carcinogenic potential can be correlated to latent membrane protein 1 (LMP1), which is essential for fibroblast and primary lymphocyte transformation. LMP1, a transmembrane protein with constitutive activity, belongs to the tumour necrosis factor receptor (TNFR) superfamily. LMP1 performs number of role in the life cycle of EBV and the pathogenesis by interfering with, reprogramming, and influencing a vast range of host cellular activities and functions that are getting well-known but still poorly understood. LMP1, pleiotropically perturbs, reprograms and balances a wide range of various processes of cell such as extracellular vesicles, epigenetics, ubiquitin machinery, metabolism, cell proliferation and survival, and also promotes oncogenic transformation, angiogenesis, anchorage-independent cell growth, metastasis and invasion, tumour microenvironment. By the help of various experiments, it is proven that EBV-encoded LMP1 activates multiple cell signalling pathways which affect antigen presentation, cell-cell interactions, chemokine and cytokine production. Therefore, it is assumed that LMP1 may perform majorly in EBV associated malignancies. For the development of novel techniques toward targeted therapeutic applications, it is essential to have a complete understanding of the LMP1 signalling landscape in order to identify potential targets. The focus of this review is on LMP1-interacting proteins and related signalling processes. We further discuss tactics for using the LMP1 protein as a potential therapeutic for cancers caused by the EBV.

Inducible miR-150 Inhibits Porcine Reproductive and Respiratory Syndrome Virus Replication by Targeting Viral Genome and Suppressor of Cytokine Signaling 1

Hosts exploit various approaches to defend against porcine reproductive and respiratory syndrome virus (PRRSV) infection. microRNAs (miRNAs) have emerged as key negative post-transcriptional regulators of gene expression and have been reported to play important roles in regulating virus infection. Here, we identified that miR-150 was differentially expressed in virus permissive and non-permissive cells. Subsequently, we demonstrated that PRRSV induced the expression of miR-150 via activating the protein kinase C (PKC)/c-Jun amino-terminal kinases (JNK)/c-Jun pathway, and overexpression of miR-150 suppressed PRRSV replication. Further analysis revealed that miR-150 not only directly targeted the PRRSV genome, but also facilitated type I IFN signaling. RNA immunoprecipitation assay demonstrated that miR-150 targeted the suppressor of cytokine signaling 1 (SOCS1), which is a negative regulator of Janus activated kinase (JAK)/signal transducer and activator of the transcription (STAT) signaling pathway. The inverse correlation between miR-150 and SOCS1 expression implies that miR-150 plays a role in regulating ISG expression. In conclusion, miR-150 expression is upregulated upon PRRSV infection. miR-150 feedback positively targets the PRRSV genome and promotes type I IFN signaling, which can be seen as a host defensive strategy.

Transcriptome of miRNA during inhibition of Bombyx mori nuclear polyhedrosis virus by geldanamycin in BmN cells

Bombyx mori nuclear polyhedrosis virus (BmNPV) is one of several viruses that cause great harm to the sericulture industry, and its pathogenic mechanism is still being explored. Geldanamycin (GA), a kind of HSP90 inhibitor, has been verified to suppress BmNPV proliferation. However, the molecular mechanism by which GA inhibits BmNPV is unclear. MicroRNAs (miRNAs) have been shown to play a key role in regulating virus proliferation and host-pathogen interactions. In this study, BmN cells infected with BmNPV were treated by GA and DMSO for 72 h, respectively, then transcriptome analysis of miRNA was performed from the GA group and the control group. As a result, a total of 29 miRNAs were differentially expressed (DE), with 13 upregulated and 16 downregulated. Using bioinformatics analysis, it was found that the target genes of DEmiRNAs were involved in ubiquitin-mediated proteolysis, phagosome, proteasome, endocytosis pathways, and so on. Six DEmiRNAs were verified by quantitative reverse-transcription polymerase chain reaction. DElong noncoding RNA (DElncRNA)-DEmiRNA-messenger RNA (mRNA) regulatory networks involved in apoptosis and immune pathways were constructed in GA-treated BmN cells, which included 12 DEmiRNA, 132 DElncRNA, and 69 mRNAs. This regulatory network enriched the functional role of miRNA in the BmNPV-silkworm interactions and improved our understanding of the molecular mechanism of HSP90 inhibitors on BmNPV proliferation.

miR-455-5p enhances 5-fluorouracil sensitivity in colorectal cancer cells by targeting PIK3R1 and DEPDC1

Our previous study has demonstrated that miR-455-5p was a tumor suppressor in colorectal cancer (CRC). This study aimed to investigate the role of miR-455-5p in 5-fluorouracil (5-Fu) in CRC. The expression of miR-455-5p, PIK3R1, and DEPDC1 was analyzed in HT-29 cells after treatment with different concentrations (0, 0.5, 2.5, and 12.5 μM) of 5-Fu. The effects of miR-455-5p on cell proliferation and apoptosis were analyzed by CCK-8 and flow cytometry. PIK3R1 and DEPDC1 were overexpressed to measure the mechanism of miR-455-5p on 5-Fu sensitivity. And the direct binding between miR-455-5p and DEPDC1 was detected by a dual-luciferase reporter assay. We found that miR-455-5p decreased, while PIK3R1 and DEPDC1 increased after 5-Fu treatment. miR-455-5p mimic significantly suppressed cell viability and elevated cell apoptosis in 5-Fu-treated HT-29 cells, whereas miR-455-5p inhibitor showed the opposite effects. Overexpression of PIK3R1 and DEPDC1 could attenuate the effects of miR-455-5p mimic on the viability and apoptosis of 5-Fu-treated cells. miR-455-5p could directly bind to DEPDC1 in HT-29 cells. In conclusion, miR-455-5p enhanced 5-Fu sensitivity by targeting PIK3R1 and DEPDC1 in CRC. This study provides a novel role of miR-455-5p in CRC and restoring miR-455-5p might be a therapeutic strategy to enhance chemosensitivity to 5-Fu.

New Look of EBV LMP1 Signaling Landscape

Simple Summary

Epstein-Barr Virus (EBV) infection is associated with various lymphomas and carcinomas as well as other diseases in humans. The transmembrane protein LMP1 plays versatile roles in EBV life cycle and pathogenesis, by perturbing, reprograming, and regulating a large range of host cellular mechanisms and functions, which have been increasingly disclosed but not fully understood so far. We summarize recent research progress on LMP1 signaling, including the novel components LIMD1, p62, and LUBAC in LMP1 signalosome and LMP1 novel functions, such as its induction of p62-mediated selective autophagy, regulation of metabolism, induction of extracellular vehicles, and activation of NRF2-mediated antioxidative defense. A comprehensive understanding of LMP1 signal transduction and functions may allow us to leverage these LMP1-regulated cellular mechanisms for clinical purposes.

Abstract

The Epstein–Barr Virus (EBV) principal oncoprotein Latent Membrane Protein 1 (LMP1) is a member of the Tumor Necrosis Factor Receptor (TNFR) superfamily with constitutive activity. LMP1 shares many features with Pathogen Recognition Receptors (PRRs), including the use of TRAFs, adaptors, and kinase cascades, for signal transduction leading to the activation of NFκB, AP1, and Akt, as well as a subset of IRFs and likely the master antioxidative transcription factor NRF2, which we have gradually added to the list. In recent years, we have discovered the Linear UBiquitin Assembly Complex (LUBAC), the adaptor protein LIMD1, and the ubiquitin sensor and signaling hub p62, as novel components of LMP1 signalosome. Functionally, LMP1 is a pleiotropic factor that reprograms, balances, and perturbs a large spectrum of cellular mechanisms, including the ubiquitin machinery, metabolism, epigenetics, DNA damage response, extracellular vehicles, immune defenses, and telomere elongation, to promote oncogenic transformation, cell proliferation and survival, anchorage-independent cell growth, angiogenesis, and metastasis and invasion, as well as the development of the tumor microenvironment. We have recently shown that LMP1 induces p62-mediated selective autophagy in EBV latency, at least by contributing to the induction of p62 expression, and Reactive Oxygen Species (ROS) production. We have also been collecting evidence supporting the hypothesis that LMP1 activates the Keap1-NRF2 pathway, which serves as the key antioxidative defense mechanism. Last but not least, our preliminary data shows that LMP1 is associated with the deregulation of cGAS-STING DNA sensing pathway in EBV latency. A comprehensive understanding of the LMP1 signaling landscape is essential for identifying potential targets for the development of novel strategies towards targeted therapeutic applications.

The Impact of microRNA Regulation on Immune Recovery in HIV-1-Infected Patients Treated during Acute Infection: A Pilot Study

microRNAs (miRNAs) are small noncoding RNAs involved in a large range of cellular activities and can be used as biomarkers and indicators for diagnosis. We investigated the alterations in miRNA profiles in immune reconstituted vs. nonimmune reconstituted HIV-1-infected individuals to assess the association between miRNAs and the occurrence of immunological nonresponses, with the aim of searching for miRNA-based biomarkers for these HIV-1-infected individuals. Thirteen immunological responders (IRs) and 12 immunological nonresponders (INRs) were recruited, and RNA was collected from the plasma samples of the 25 HIV-1-infected individuals at both baseline and after 24 months of maintaining virological suppression (VS). Next-generation sequencing was used to detect miRNAs and evaluate the expression differences in miRNAs between IR and INR patients and between baseline and after 24 months of maintaining VS. Samples from 13 IRs and 11 INRs were successfully sequenced. The horizontal comparison of differentially expressed miRNAs between the groups and the longitudinal comparison of differentially expressed miRNAs between baseline and after 24 months of maintaining VS showed that a large proportion of miRNAs in INRs are downregulated compared to the levels in IRs. We also found that the miRNA let-7d-5p was downregulated in 9 INRs but only in 2 IRs by more than 2-fold. The difference was significant. In summary, these results demonstrate for the first time that a large proportion of miRNAs are downregulated in INRs compared with IRs, and the miRNA let-7d-5p is a potential biomarker for INRs.

Exosomal miRNAs: novel players in viral infection

Exosomes are secreted nanovesicles that are able to transfer their cargo (such as miRNAs) between cells. To determine to what extent exosomes and exosomal miRNAs are involved in the pathogenesis, progression and diagnosis of viral infections. The scientific literature (PubMed and Google Scholar) was searched from 1970 to 2019. The complex biogenesis of exosomes and miRNAs was reviewed. Exosomes contain both viral and host miRNAs that can be used as diagnostic biomarkers for viral diseases. Viral proteins can alter miRNAs, and conversely miRNAs can alter the host response to viral infections in a positive or negative manner. It is expected that exosomal miRNAs will be increasingly used for diagnosis, monitoring and even treatment of viral infections.

DEF Cell-Derived Exosomal miR-148a-5p Promotes DTMUV Replication by Negative Regulating TLR3 Expression

Duck tembusu virus (DTMUV) is a single-stranded, positive-polarity RNA flavivirus that has caused considerable economic losses in China in recent years. Innate immunity represents the first line of defense against invading pathogens and serves as an important role in resisting viral infections. In this study, we found that the infection of ducks by DTMUV triggers Toll-like receptors (TLRs) and (RIG-I)-like receptors (RLRs) signaling pathways and inducing abundant of pro-inflammatory factors and type I interferons (IFNs), in which melanoma differentiation-associated gene 5 (MDA5) and Toll-like receptor 3 (TLR3) play important immunity roles, they can inhibit the replication process of DTMUV via inducing type I IFNs. Moreover, we demonstrated that type I IFNs can inhibit the DTMUV replication process in a time- and dose-dependent manner. Exosomes are small membrane vesicles that have important roles in intercellular communication. MicroRNAs (miRNAs) are small non-coding RNAs that can modulate gene expression and are common substances in exosomes. In our experiment, we successfully isolated DEF cells derived exosome for the first time and explored its function. Firstly, we found the expression of miR-148a-5p is significantly decreased following DTMUV infect. Then we found miR-148a-5p can target TLR3 and down-regulate the expression of TLR3, serving as a negative factor in innate immunity. Unfortunately, we cannot find miRNAs with different expression changes that can target MDA5. Lastly, our experimental results showed that TLR3 was one of the causes of miR-148a-5p reduction, suggesting that the high level of TLR3 after DTMUV infect can both trigger innate immunity and suppress miR-148a-5p to resist DTMUV.

Identification and Characterization of MicroRNAs in Skin of Chinese Giant Salamander (Andrias davidianus) by the Deep Sequencing Approach

MicroRNAs (miRNA) play a pivotal role in regulating a broad range of biological processes, acting by cleaving mRNAs or by translational repression. However, the miRNAs from skin of Andrias davidianus have not been reported. In this study, a small-RNA cDNA library was constructed and sequenced from skin of A. davidianus. A total of 513 conserved miRNAs belonging to 174 families were identified. The remaining 108 miRNAs we identified were novel and likely to be skin tissue-specific but were expressed at low levels. The presence of randomly selected 15 miRNAs identified and their expression in eight different tissues from A. davidianus were validated by stem-loop qRT-PCR. For better understanding the functions of miRNAs, 129,791 predicated target genes were analyzed by GO and their pathways illustrated by KEGG pathway analyses. The results show that these identified miRNAs from A. davidianus skin are involved in a broad range of physiological functions including metabolism, growth, development, and immune responses. This study exhaustively identifies miRNAs and their target genes, which will ultimately pave the way for understanding their role in skin of A. davidianus and other amphibians. Further studies are necessary to better understand miRNA-mediated gene regulation.

mircoRNA-3162-3p is a potential biomarker to identify new infections in HIV-1-infected patients

BACKGROUND

Identification of new HIV infections (HIV incidence) is critical for monitoring AIDS epidemic and assessing the effectiveness of intervention measures. However, current methods for distinguishing new infections from newly diagnosed HIV-1 patients are still imperfect. We explored utilizing miRNAs as biomarker to identify HIV new infections.

METHODS

According to the HIV-1 status and the estimated duration of infection (EDI), we enrolled participants and divided them into three groups: healthy control, new infection (within 1 year), and old infection (longer than 1 year). Participants were assigned into screening set or validation set. miRNA microarray was performed in screening set and the differentially expressed miRNAs were screened out. The differentially expressed miRNAs were further confirmed in validation set and HIV-1 IIIB-MT2 cells infection system.

RESULTS

In screening set, 5 miRNAs including miR-1291, miR-3609, miR-3162-3p, miR-874-5p and miR-4258 were screened out for their differential expression in plasma among three groups. In validation set, down- trend of miR-3162-3p was validated from healthy control, new infection to old infection groups. In HIV-1 IIIB-MT2 system, the levels of miR-3162-3p also decreased along with infection duration in vitro. Sensitivity and specificity for miR-3162-3p to distinguish new infection from old infection were 100.0% and 71.43%, respectively, with the cut-off value of 0.916.

CONCLUSION

miR-3162-3p in plasma could be a potential microRNA biomarker to identify HIV new infections in HIV-1 infected patients.

MERS-CoV infection in humans is associated with a pro-inflammatory Th1 and Th17 cytokine profile

The Middle East respiratory syndrome coronavirus (MERS-CoV) has been recognized as a highly pathogenic virus to humans that infects the respiratory tract and is associated with high morbidity and mortality. Studies in animal models suggest that MERS-CoV infection induces a strong inflammatory response, which may be related to the severity of disease. Data showing the cytokine profiles in humans during the acute phase of MERS-CoV infection are limited. In this study, we have analyzed the profile of cytokine responses in plasma samples from patients with confirmed MERS-CoV infections (n = 7) compared to healthy controls (n = 13). The cytokine profiles, including T helper (Th) 1, Th2 and Th17 responses, were analyzed using cytometric bead array (CBA). A prominent pro-inflammatory Th1 and Th17 response was clearly seen in patients with MERS-CoV infection, with markedly increased concentrations of IFN-γ, TNF-α, IL-15 and IL-17 compared to controls. IL-12 expression levels showed no difference between patients with MERS-CoV infection and the healthy controls despite the significantly increased levels of IFN-α2 and IFN-γ (P < .01). No changes were observed in the levels of IL-2, IL-4, IL-5, IL-13, and TGF-α (P > .05). Our results demonstrate a marked pro-inflammatory cytokine response during the acute phase of MERS-CoV infection in humans.

"Toll-free" pathways for production of type I interferons

Pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs) are recognized by different cellular pathogen recognition receptors (PRRs), which are expressed on cell membrane or in the cytoplasm of cells of the innate immune system. Nucleic acids derived from pathogens or from certain cellular conditions represent a large category of PAMPs/DAMPs that trigger production of type I interferons (IFN-I) in addition to pro-inflammatory cytokines, by specifically binding to intracellular Toll-like receptors or cytosolic receptors. These cytosolic receptors, which are not related to TLRs and we call them “Toll-free” receptors, include the RNA-sensing RIG-I like receptors (RLRs), the DNA-sensing HIN200 family, and cGAS, amongst others. Viruses have evolved myriad strategies to evoke both host cellular and viral factors to evade IFN-I-mediated innate immune responses, to facilitate their infection, replication, and establishment of latency. This review outlines these “Toll-free” innate immune pathways and recent updates on their regulation, with focus on cellular and viral factors with enzyme activities.

Potential use of microRNA-200c as a prognostic marker in non-small cell lung cancer

MicroRNAs (miRNAs/miRs) are a class of small, highly conserved non-coding RNAs that can serve either oncogenic or tumor-suppressive roles in a wide variety of tumors. miR-200c is a member of the miR-200 family whose specific role in non-small cell lung cancer (NSCLC) has not yet been elucidated. The purpose of the present study was to detect the expression level of miR-200c in NSCLC, and to analyze its association with clinicopathological factors and patient prognosis. The present study determined the expression levels of miR-200c in 110 tumor samples collected from patients diagnosed with NSCLC who underwent complete tumor resection with regional lymph node dissection, as assessed by reverse transcription-quantitative polymerase chain reaction. The association between the expression level of miR-200c and clinicopathological features and patient prognosis was also analyzed. The results showed that miR-200c overexpression was detected in 66 of the 110 cases and was significantly associated with positive lymph node metastasis (P<0.001). Univariate survival analysis demonstrated that high miR-200c expression, positive lymph node metastasis and advanced Tumor-Node-Metastasis (TNM) classification stage significantly predicted decreased 5-year disease-free survival rates (all P<0.05) and poor 5-year overall survival rates (all P<0.01), respectively. The results of multivariate Cox regression analysis showed that TNM stage and miR-200c expression retained its significance as an independent prognostic factor for unfavorable 5-year disease-free survival rates (P<0.05) and poor 5-year overall survival rates (P<0.01). The present findings suggest that miR-200c overexpression is significantly associated with poor survival rates in NSCLC and that miR-200c could play an oncogenic role. miR-200c may have clinical potential as a promising prognostic predictor for patients with NSCLC.

MiR-451 as a new tumor marker for gastric cancer

Gastric cancer is the second most common malignancy in China. However, the prognosis for gastric cancer patients remains poor. The purpose of this study was to investigate whether miR-451 was a potential prognostic biomarker for gastric cancer. Fresh tissues were immediately frozen in liquid nitrogen until use. The plasma was extracted and quantitative real-time polymerase chain reaction was performed to detect miR-451 expression. The Student's t test analysis and multivariate Cox regression analysis were performed to analyze expression of miR-451. The analysis results showed that the expression level of miR-451 was decreased expression in gastric cancer tissue. The down-regulation of miR-451 tended to be positively correlated with tumor stage, lymphatic metastasis and shorter overall survival of patients. MiR-451 may be a potential biomarker and a potential therapeutic target for the diagnoses and prognosis of gastric cancer.

Role of Natural Killer Cells in HIV-Associated Malignancies

Now in its fourth decade, the burden of HIV disease still persists, despite significant milestone achievements in HIV prevention, diagnosis, treatment, care, and support. Even with long-term use of currently available antiretroviral therapies (ARTs), eradication of HIV remains elusive and now poses a unique set of challenges for the HIV-infected individual. The occurrence of HIV-associated non-AIDS-related comorbidities outside the scope of AIDS-defining illnesses, in particular non-AIDS-defining cancers, is much greater than the age-matched uninfected population. The underlying mechanism is now recognized in part to be related to the immune dysregulated and inflammatory status characteristic of HIV infection that persists despite ART. Natural killer (NK) cells are multifunctional effector immune cells that play a critical role in shaping the innate immune responses to viral infections and cancer. NK cells can modulate the adaptive immune response via their role in dendritic cell (DC) maturation, removal of immature tolerogenic DCs, and their ability to produce immunoregulatory cytokines. NK cells are therefore poised as attractive therapeutic targets that can be harnessed to control or clear both HIV and HIV-associated malignancies. To date, features of the tumor microenvironment and the evolution of NK-cell function among individuals with HIV-related malignancies remain unclear and may be distinct from malignancies observed in uninfected persons. This review intends to uncouple anti-HIV and antitumor NK-cell features that can be manipulated to halt the evolution of HIV disease and HIV-associated malignancies and serve as potential preventative and curative immunotherapeutic options.

Peripheral Blood Epstein-Barr Viral Nucleic Acid Surveillance as a Marker for Posttransplant Cancer Risk

Several viruses, such as Epstein-Barr virus, are now known to be associated with several human cancers, but not all patients with these viral infections develop cancer. In transplantation, such viruses often have a prolonged time gap from infection to cancer development, and many are preceded by a period of circulating and detectable nucleic acids in the peripheral blood compartment. The interpretation of a viral load as a measure of posttransplant risk of developing cancer depends on the virus, the cancer and associated pathogenic factors. This review describes the current state of knowledge regarding the utility and limitations of peripheral blood nucleic acid testing for Epstein-Barr virus in surveillance and risk prediction for posttransplant lymphoproliferative disorders.

NOS1 S-nitrosylates PTEN and inhibits autophagy in nasopharyngeal carcinoma cells

Autophagy is a cellular survival mechanism that involves the catabolic degradation of damaged proteins and organelles during periods of metabolic stress, and when overly stimulated, commonly contributes to cell death. Nitric oxide (NO), a potent cellular messenger, participates in a complex mechanism which assists in controlling autophagy. However, the mechanism by which endogenous NO formed by distinct isoforms of nitric oxide synthase (NOS) helps to regulate autophagy in cancer cells remains unclear. Here we report that NOS1 reduces excessive levels of autophagy and promotes the survival of nasopharyngeal carcinoma cells. We found that inhibition of NOS1 increased cell death resulting from siRNA or the use of pharmacologic agents; and this effect was reversed by the autophagy inhibitor, chloroquine. The role of NOS1 in the autophagy process depended on the activation of AKT/mTOR signaling by S-nitrosylation of phosphatase and tensin homolog (PTEN) proteins. The mechanism by which NOS1 modifies PTEN protein might involve a direct interaction between these two molecules. Moreover, in an in vivo study, the NOS1 inhibitor N(G)-nitro-L-arginine methyl ester activated AKT/mTOR signaling and promoted autophagy in xenograph tumors. Our studies demonstrated that NOS1 prevents excessive autophagy via S-nitrosylation of PTEN, and activation of the AKT/mTOR signaling pathway. PTEN and the AKT/mTOR signaling pathway are promising targets for improving the chemotherapeutic treatment of cancer.

Genome-Wide Analysis of Differentially Expressed microRNA in Bombyx mori Infected with Nucleopolyhedrosis Virus

Bombyx mori nucleopolyhedrosis virus (BmNPV) is a major pathogen that threatens the growth and sustainability of the sericulture industry. Since microRNAs (miRNAs) have been shown to play important roles in host-pathogen interactions, in this study we investigated the effects of BmNPV infection on silkworm microRNAs expression profile. To achieve this, we constructed and deep-sequenced two small RNA libraries generated from BmNPV infected and un-infected larvae. The results revealed that 38 silkworm miRNAs were differentially expressed after BmNPV infection. Based on the GO analysis, their predicted target genes were found to be involved in diverse functions such as binding, catalytic, virion and immune response to stimulus suggesting their potential roles in host-virus interactions. Using the dual-luciferase reporter assay, we confirmed that Bmo-miR-277-5p, up-regulated in BmNPV-infected larvae, targeted the B. mori DNA cytosine-5 methyltransferase (Dnmt2) gene which may play potential role in silkworm-BmNPV interaction. These results provide new insights into exploring the interaction mechanism between silkworm and BmNPV.

Protection of CD4+ T cells from hepatitis C virus infection-associated senescence via ΔNp63-miR-181a-Sirt1 pathway

T cell dysfunction has a crucial role in establishing and maintaining viral persistence. We have previously shown a decline in miR-181a, which regulates CD4⁺ T cell responses via DUSP6 overexpression, in individuals with hepatitis C virus (HCV) infection. Here, we describe accelerated T cell senescence in HCV-infected individuals compared with age- and sex-matched healthy subjects. Mechanistic studies revealed that up-regulation of transcription factor ΔNp63 led to the decline of miR-181a expression, resulting in an overexpression of the antiaging protein Sirt1, in CD4⁺ T cells from HCV-infected individuals. Either reconstituting miR-181a or silencing ΔNp63 or Sirt1 expression in CD4⁺ T cells led to accelerated T cell senescence, as evidenced by an increased senescence-associated β-galactosidase (SA-β-gal) expression, shortened telomere length, and decreased EdU incorporation; this suggests that HCV-induced T cell senescence is counterregulated by the ΔNp63-miR-181a-Sirt1 pathway. An increase of IL-2 production was observed in these senescent CD4⁺ T cells and was driven by a markedly reduced frequency of Foxp3⁺ regulatory T (T_reg) cells and increased number of Foxp3^- effector T (T_eff) cells upon manipulating the ΔNp63-miR-181a-Sirt1 pathway. In conclusion, these findings provide novel mechanistic insights into how HCV uses cellular senescent pathways to regulate T cell functions, revealing new targets for rejuvenating impaired T cell responses during chronic viral infection.

MicroRNA-19b-3p Modulates Japanese Encephalitis Virus-Mediated Inflammation via Targeting RNF11

Japanese encephalitis virus (JEV) can invade the central nervous system and consequently induce neuroinflammation, which is characterized by profound neuronal cell damage accompanied by astrogliosis and microgliosis. Albeit microRNAs (miRNAs) have emerged as major regulatory noncoding RNAs with profound effects on inflammatory response, it is unknown how astrocytic miRNAs regulate JEV-induced inflammation. Here, we found the involvement of miR-19b-3p in regulating the JEV-induced inflammatory responsein vitroandin vivo The data demonstrated that miR-19b-3p is upregulated in cultured cells and mouse brain tissues during JEV infection. Overexpression of miR-19b-3p led to increased production of inflammatory cytokines, including tumor necrosis factor alpha, interleukin-6, interleukin-1β, and chemokine (C-C motif) ligand 5, after JEV infection, whereas knockdown of miR-19b-3p had completely opposite effects. Mechanistically, miR-19b-3p modulated the JEV-induced inflammatory response via targeting ring finger protein 11, a negative regulator of nuclear factor kappa B signaling. We also found that inhibition of ring finger protein 11 by miR-19b-3p resulted in accumulation of nuclear factor kappa B in the nucleus, which in turn led to higher production of inflammatory cytokines.In vivosilencing of miR-19b-3p by a specific antagomir reinvigorates the expression level of RNF11, which in turn reduces the production of inflammatory cytokines, abrogates gliosis and neuronal cell death, and eventually improves the survival rate in the mouse model. Collectively, our results demonstrate that miR-19b-3p positively regulates the JEV-induced inflammatory response. Thus, miR-19b-3p targeting may constitute a thought-provoking approach to rein in JEV-induced inflammation.

IMPORTANCE

Japanese encephalitis virus (JEV) is one of the major causes of acute encephalitis in humans worldwide. The pathological features of JEV-induced encephalitis are inflammatory reactions and neurological diseases resulting from glia activation. MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression posttranscriptionally. Accumulating data indicate that miRNAs regulate a variety of cellular processes, including the host inflammatory response under pathological conditions. Recently, a few studies demonstrated the role of miRNAs in a JEV-induced inflammatory response in microglia; however, their role in an astrocyte-derived inflammatory response is largely unknown. The present study reveals that miR-19b-3p targets ring finger protein 11 in glia and promotes inflammatory cytokine production by enhancing nuclear factor kappa B activity in these cells. Moreover, administration of an miR-19b-3p-specific antagomir in JEV-infected mice reduces neuroinflammation and lethality. These findings suggest a new insight into the molecular mechanism of the JEV-induced inflammatory response and provide a possible therapeutic entry point for treating viral encephalitis.

Epigenetic control of HIV-1 post integration latency: implications for therapy

With the development of effective combined anti-retroviral therapy (cART), there is significant reduction in deaths associated with human immunodeficiency virus type 1 (HIV-1) infection. However, the complete cure of HIV-1 infection is difficult to achieve without the elimination of latent reservoirs which exist in the infected individuals even under cART regimen. These latent reservoirs established during early infection have long life span, include resting CD4⁺ T cells, macrophages, central nervous system (CNS) resident macrophage/microglia, and gut-associated lymphoid tissue/macrophages, and can actively produce virus upon interruption of the cART. Several epigenetic and non-epigenetic mechanisms have been implicated in the regulation of viral latency. Epigenetic mechanisms such as histone post translational modifications (e.g., acetylation and methylation) and DNA methylation of the proviral DNA and microRNAs are involved in the establishment of HIV-1 latency. The better understanding of epigenetic mechanisms modulating HIV-1 latency could give clues for the complete eradication of these latent reservoirs. Several latency-reversing agents (LRA) have been found effective in reactivating HIV-1 reservoirs in vitro, ex vivo, and in vivo. Some of these agents target epigenetic modifications to elicit viral expression in order to kill latently infected cells through viral cytopathic effect or host immune response. These therapeutic approaches aimed at achieving a sterilizing cure (elimination of HIV-1 from the human body). In the present review, we will discuss our current understanding of HIV-1 epigenomics and how this information can be moved from the laboratory bench to the patient’s bedside.