HSV-1 biology and life cycle

T84 Monolayer Cell Cultures Support Productive HBoV and HSV-1 Replication and Enable In Vitro Co-Infection Studies

Based on several clinical observations it was hypothesized that herpesviruses may influence the replication of human bocaviruses, the second known parvoviruses that have been confirmed as human pathogens. While several cell lines support the growth of HSV-1, HBoV-1 was exclusively cultivated on air-liquid interface cultures, the latter being a rather complicated, slow, and low throughput system. One of the cell lines are T84 cells, which are derived from the lung metastasis of a colorectal tumor. In this study, we provide evidence that T84 also supports HBoV replication when cultivated as monolayers, while simultaneously being permissive for HSV-1. The cell culture model thus would enable co-infection studies of both viruses and is worth being optimized for high throughput studies with HBoV-1. Additionally, the study provides evidence for a supporting effect of HSV-1 on the replication and packaging of HBoV-1 progeny DNA into DNase-resistant viral particles.

USP7 promotes cervical cancer progression by stabilizing MTDH expression through deubiquitination

BACKGROUND

Metadherin (MTDH) and ubiquitin specific protease 7 (USP7) have been identified to involve in the tumorigenesis of cervical cancer (CC). USP7 is one of the deubiquitinating enzymes. Here, this study aimed to explore whether USP7 affected CC progression via interacting with MTDH and regulating its stability via deubiquitination.

METHODS

qRT-PCR and western blotting assays detected the levels of genes and proteins. Functional analysis was conducted using 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, transwell, and tube formation assays, respectively. Proteins between USP7 and MTDH were identified by co-immunoprecipitation assay. A mouse xenograft model was established for in vivo analysis.

RESULTS

MTDH was highly expressed in CC tissues and cells, silencing of MTDH suppressed CC cell proliferation, migration, invasion, angiogenesis, and macrophage M2 polarization. Mechanistically, USP7 directly bound to MTDH, and maintained its stability by removing ubiquitination on MTDH. CC tissues and cells showed high USP7 expression, and USP7 knockdown also inhibited CC cell proliferation, migration, invasion, angiogenesis and macrophage M2 polarization, and these effects mediated by USP7 knockdown were reversed by MTDH overexpression. Moreover, USP7 knockdown impeded CC growth in vivo by regulating MTDH.

CONCLUSION

Collectively, USP7 promoted CC cell proliferation, migration, invasion, angiogenesis, and macrophage M2 polarization in vitro, as well as tumor growth in vivo by regulating MTDH.

Viral MicroRNAs in Herpes Simplex Virus 1 Pathobiology

Simplexvirus humanalpha1 (Herpes simplex virus type 1 [HSV-1]) infects millions of people globally, manifesting as vesiculo-ulcerative lesions of the oral or genital mucosa. After primary infection, the virus establishes latency in the peripheral neurons and reactivates sporadically in response to various environmental and genetic factors. A unique feature of herpesviruses is their ability to encode tiny noncoding RNAs called microRNA (miRNAs). Simplexvirus humanalpha1 encodes eighteen miRNA precursors that generate twentyseven different mature miRNA sequences. Unique Simplexvirus humanalpha1 miRNAs repertoire is expressed in lytic and latent stages and exhibits expressional disparity in various cell types and model systems, suggesting their key pathological functions. This review will focus on elucidating the mechanisms underlying the regulation of host-virus interaction by HSV-1 encoded viral miRNAs. Numerous studies have demonstrated sequence- specific targeting of both viral and host transcripts by Simplexvirus humanalpha1 miRNAs. While these noncoding RNAs predominantly target viral genes involved in viral life cycle switch, they regulate host genes involved in antiviral immunity, thereby facilitating viral evasion and lifelong viral persistence inside the host. Expression of Simplexvirus humanalpha1 miRNAs has been associated with disease progression and resolution. Systemic circulation and stability of viral miRNAs compared to viral mRNAs can be harnessed to utilize their potential as diagnostic and prognostic markers. Moreover, functional inhibition of these enigmatic molecules may allow us to devise strategies that have therapeutic significance to contain Simplexvirus humanalpha1 infection.

CLEAR Strategy Inhibited HSV Proliferation Using Viral Vectors Delivered CRISPR-Cas9

Herpes simplex virus type 1 (HSV-1) is a leading cause of encephalitis and infectious blindness. The commonly used clinical therapeutic drugs are nucleoside analogues such as acyclovir. However, current drugs for HSV cannot eliminate the latent virus or viral reactivation. Therefore, the development of new treatment strategies against latent HSV has become an urgent need. To comprehensively suppress the proliferation of HSV, we designed the CLEAR strategy (coordinated lifecycle elimination against viral replication). VP16, ICP27, ICP4, and gD-which are crucial genes that perform significant functions in different stages of the HSV infection lifecycle-were selected as targeting sites based on CRISPR-Cas9 editing system. In vitro and in vivo investigations revealed that genome editing by VP16, ICP27, ICP4 or gD single gene targeting could effectively inhibit HSV replication. Moreover, the combined administration method (termed "Cocktail") showed superior effects compared to single gene editing, which resulted in the greatest decrease in viral proliferation. Lentivirus-delivered CRISPR-Cas9/gRNA editing could effectively block HSV replication. The CLEAR strategy may provide new insights into the potential treatment of refractory HSV-1-associated diseases, particularly when conventional approaches have encountered resistance.

Ethosomal Gel for Topical Administration of Dimethyl Fumarate in the Treatment of HSV-1 Infections

The infections caused by the HSV-1 virus induce lesions on the lips, mouth, face, and eye. In this study, an ethosome gel loaded with dimethyl fumarate was investigated as a possible approach to treat HSV-1 infections. A formulative study was conducted, evaluating the effect of drug concentration on size distribution and dimensional stability of ethosomes by photon correlation spectroscopy. Ethosome morphology was investigated by cryogenic transmission electron microscopy, while the interaction between dimethyl fumarate and vesicles, and the drug entrapment capacity were respectively evaluated by FTIR and HPLC. To favor the topical application of ethosomes on mucosa and skin, different semisolid forms, based on xanthan gum or poloxamer 407, were designed and compared for spreadability and leakage. Dimethyl fumarate release and diffusion kinetics were evaluated in vitro by Franz cells. The antiviral activity against HSV-1 was tested by plaque reduction assay in Vero and HRPE monolayer cells, while skin irritation effect was evaluated by patch test on 20 healthy volunteers. The lower drug concentration was selected, resulting in smaller and longer stable vesicles, mainly characterized by a multilamellar organization. Dimethyl fumarate entrapment in ethosome was 91% w/w, suggesting an almost total recovery of the drug in the lipid phase. Xanthan gum 0.5%, selected to thicken the ethosome dispersion, allowed to control drug release and diffusion. The antiviral effect of dimethyl fumarate loaded in ethosome gel was demonstrated by a reduction in viral growth both 1 h and 4 h post-infection. Moreover, the patch test demonstrated the safety of the ethosomal gel applied on the skin.

Engineering antiviral immune-like systems for autonomous virus detection and inhibition in mice

The ongoing COVID-19 pandemic has demonstrated that viral diseases represent an enormous public health and economic threat to mankind and that individuals with compromised immune systems are at greater risk of complications and death from viral diseases. The development of broad-spectrum antivirals is an important part of pandemic preparedness. Here, we have engineer a series of designer cells which we term autonomous, intelligent, virus-inducible immune-like (ALICE) cells as sense-and-destroy antiviral system. After developing a destabilized STING-based sensor to detect viruses from seven different genera, we have used a synthetic signal transduction system to link viral detection to the expression of multiple antiviral effector molecules, including antiviral cytokines, a CRISPR-Cas9 module for viral degradation and the secretion of a neutralizing antibody. We perform a proof-of-concept study using multiple iterations of our ALICE system in vitro, followed by in vivo functionality testing in mice. We show that dual output ALICE_SaCas9+Ab system delivered by an AAV-vector inhibited viral infection in herpetic simplex keratitis (HSK) mouse model. Our work demonstrates that viral detection and antiviral countermeasures can be paired for intelligent sense-and-destroy applications as a flexible and innovative method against virus infection.

Quindoline-derivatives display potent G-quadruplex-mediated antiviral activity against herpes simplex virus 1

G-quadruplexes (G4s) are non-canonical nucleic acid structures that regulate key biological processes, from transcription to genome replication both in humans and viruses. The herpes simplex virus-1 (HSV-1) genome is prone to form G4s that, along with proteins, regulate its viral cycle. General G4 ligands have been shown to hamper the viral cycle, pointing to viral G4s as original antiviral targets. Because cellular G4s are also normally present in infected cells, the quest for improved anti-HSV-1 G4 ligands is still open. Here, we evaluated a series of new quindoline-derivatives which showed high binding to and stabilization of the viral G4s. They displayed nanomolar-range anti-HSV-1 activity paralleled by negligible cytotoxicity in human cells, thus proving remarkable selectivity. The best-in-class compound inhibited the viral life cycle at the early times post infection up to the step of viral genome replication. In infected human cells, it reduced expression of ICP4, the main viral transcription factor, by stabilizing the G4s embedded in ICP4 promoter. Quindoline-derivatives thus emerge as a new class of G4 ligands with potent dual anti HSV-1 activity.

The Role of Pyrazolopyridine Derivatives on Different Steps of Herpes Simplex Virus Type-1 In Vitro Replicative Cycle

Herpes simplex virus type-1 (HSV-1) infection causes several disorders, and acyclovir is used as a reference compound. However, resistant strains are commonly observed. Herein, we investigate the effects of N-heterocyclic compounds (pyrazolopyridine derivatives), named ARA-04, ARA-05, and AM-57, on HSV-1 in vitro replication. We show that the 50% effective concentration (EC₅₀) values of the compounds ARA-04, ARA-05, and AM-57 were 1.00 ± 0.10, 1.00 ± 0.05, and 0.70 ± 0.10 µM, respectively. These compounds presented high 50% cytotoxic concentration (CC₅₀) values, which resulted in a selective index (SI) of 1000, 1000, and 857.1 for ARA-04, ARA-05, and AM-57, respectively. To gain insight into which step of the HSV-1 replication cycle these molecules would impair, we performed adsorption and penetration inhibition assays and time-of-addition experiments. Our results indicated that ARA-04 and ARA-05 affected viral adsorption, while AM-57 interfered with the virus replication during its α- and γ-phases and decreased ICP27 content during initial and late events of HSV-1 replication. In addition, we also observed that AM-57 caused a strong decrease in viral gD content, which was reinforced by in silico calculations that suggested AM-57 interacts preferentially with the viral complex between a general transcription factor and virion protein (TFIIBc-VP16). In contrast, ARA-04 and ARA-05 interact preferentially in the proteins responsible for the viral adsorption process (nectin-1 and glycoprotein). Thus, our results suggest that the 1H-pyrazolo[3,4-b]pyridine derivatives inhibit the HSV-1 replicative cycle with a novel mechanism of action, and its scaffold can be used as a template for the synthesis of promising new molecules with antiviral effects, including to reinforce the presented data herein for a limited number of molecules.

The Importance of CXCL1 in Physiology and Noncancerous Diseases of Bone, Bone Marrow, Muscle and the Nervous System

This review describes the role of CXCL1, a chemokine crucial in inflammation as a chemoattractant for neutrophils, in physiology and in selected major non-cancer diseases. Due to the vast amount of available information, we focus on the role CXCL1 plays in the physiology of bones, bone marrow, muscle and the nervous system. For this reason, we describe its effects on hematopoietic stem cells, myoblasts, oligodendrocyte progenitors and osteoclast precursors. We also present the involvement of CXCL1 in diseases of selected tissues and organs including Alzheimer’s disease, epilepsy, herpes simplex virus type 1 (HSV-1) encephalitis, ischemic stroke, major depression, multiple sclerosis, neuromyelitis optica, neuropathic pain, osteoporosis, prion diseases, rheumatoid arthritis, tick-borne encephalitis (TBE), traumatic spinal cord injury and West Nile fever.

A novel H129-based anterograde monosynaptic tracer exhibits features of strong labeling intensity, high tracing efficiency, and reduced retrograde labeling

Background

Viral tracers are important tools for mapping brain connectomes. The feature of predominant anterograde transneuronal transmission offers herpes simplex virus-1 (HSV-1) strain H129 (HSV1-H129) as a promising candidate to be developed as anterograde viral tracers. In our earlier studies, we developed H129-derived anterograde polysynaptic tracers and TK deficient (H129-dTK) monosynaptic tracers. However, their broad application is limited by some intrinsic drawbacks of the H129-dTK tracers, such as low labeling intensity due to TK deficiency and potential retrograde labeling caused by axon terminal invasion. The glycoprotein K (gK) of HSV-1 plays important roles in virus entry, egress, and virus-induced cell fusion. Its deficiency severely disables virus egress and spread, while only slightly limits viral genome replication and expression of viral proteins. Therefore, we created a novel H129-derived anterograde monosynaptic tracer (H129-dgK) by targeting gK, which overcomes the limitations of H129-dTK.

Methods

Using our established platform and pipeline for developing viral tracers, we generated a novel tracer by deleting the gK gene from the H129-G4. The gK-deleted virus (H129-dgK-G4) was reconstituted and propagated in the Vero cell expressing wildtype H129 gK (gK_wt) or the mutant gK (gK_mut, A40V, C82S, M223I, L224V, V309M), respectively. Then the obtained viral tracers of gK_mut pseudotyped and gK_wt coated H129-dgK-G4 were tested in vitro and in vivo to characterize their tracing properties.

Results

H129-dgK-G4 expresses high levels of fluorescent proteins, eliminating the requirement of immunostaining for imaging detection. Compared to the TK deficient monosynaptic tracer H129-dTK-G4, H129-dgK-G4 labeled neurons with 1.76-fold stronger fluorescence intensity, and visualized 2.00-fold more postsynaptic neurons in the downstream brain regions. gK_mut pseudotyping leads to a 77% decrease in retrograde labeling by reducing axon terminal invasion, and thus dramatically improves the anterograde-specific tracing of H129-dgK-G4. In addition, assisted by the AAV helper trans-complementarily expressing gK_wt, H129-dgK-G4 allows for mapping monosynaptic connections and quantifying the circuit connectivity difference in the Alzheimer’s disease and control mouse brains.

Conclusions

gK_mut pseudotyped H129-dgK-G4, a novel anterograde monosynaptic tracer, overcomes the limitations of H129-dTK tracers, and demonstrates desirable features of strong labeling intensity, high tracing efficiency, and improved anterograde specificity.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13024-021-00508-6.

Mangiferin-Loaded Smart Gels for HSV-1 Treatment

Infections due to HSV-1 affect many people all over the world. To counteract this pathology, usually characterized by perioral sores or by less frequent serious symptoms including keratitis, synthetic antiviral drugs are employed, such as acyclovir, often resulting in resistant viral strains under long-term use. Many plant-derived compounds, such as mangiferin and quercetin, have demonstrated antiviral potentials. In this study, smart semisolid forms based on phosphatidylcholine and Pluronic were investigated as delivery systems to administer mangiferin on skin and mucosae affected by HSV-1 infection. Particularly, lecithin organogels, Pluronic gel, and Pluronic lecithin organogels were formulated and characterized. After the selection of gel compositions, physical aspects, such as rheological behavior, spreadability, leakage, and adhesion were evaluated, suggesting a scarce suitability of the lecithin organogel for topical administration. Mangiferin was efficiently included in all type of gels. An in vitro study based on the Franz cell enabled us to find evidence of the gel capability to control drug diffusion, especially in the case of Pluronic organogel, while an in vivo study conducted on human volunteers demonstrated the safeness of all of the gels after cutaneous administration. Furthermore, a plaque reduction assay demonstrated the virucidal effect of mangiferin loaded in a Pluronic gel and a Pluronic lecithin organogel against the HSV-1 KOS strain.

Risk factors associated with the development of oral mucositis in pediatric oncology patients: Systematic review and meta-analysis

OBJECTIVES

Oral mucositis (OM) is an acute toxicity related to cancer treatment. This systematic review aimed to identify potential risk factors associated with the development of OM in pediatric cancer patients.

METHODS

A search was performed in four electronic databases to identify studies that analyzed risk factors for OM in pediatric cancer patients.

RESULTS

Nineteen articles were included. The incidence of OM ranged from 20% to 80.4%. Chemotherapeutic agents were potential risk factors for OM in eight (42%) studies. Hematological, hepatic, and renal parameters were also considered in eight (42%) studies, while specific individual factors were reported in five (26.3%) studies. Baseline disease, oral microbiota, genetic profile, and biomarkers were reported in four (21.5%) studies each. Meta-analysis showed that groups submitted to high-risk chemotherapy for OM had a 2.79-fold increased risk of OM.

CONCLUSIONS

Identifying risk factors for OM is essential in order to allow individualized and early prevention treatment.

Dysregulation of the Ubiquitin Proteasome System in Human Malignancies: A Window for Therapeutic Intervention

Simple Summary

The ubiquitin proteasome system (UPS) governs the non-lysosomal degradation of oxidized, damaged, or misfolded proteins in eukaryotic cells. Dysregulation of the UPS results in loss of ability to maintain protein quality through proteolysis, and is closely related to the development of various malignancies and tumorigenesis. Here, we provide a comprehensive general overview on the regulation and roles of UPS and discuss the mechanisms linking dysregulated UPS to human malignancies. Inhibitors developed against components of the UPS, which include U.S. Food and Drug Administration FDA-approved and those currently undergoing clinical trials, are also presented in this review.

Abstract

The ubiquitin proteasome system (UPS) governs the non-lysosomal degradation of oxidized, damaged, or misfolded proteins in eukaryotic cells. This process is tightly regulated through the activation and transfer of polyubiquitin chains to target proteins which are then recognized and degraded by the 26S proteasome complex. The role of UPS is crucial in regulating protein levels through degradation to maintain fundamental cellular processes such as growth, division, signal transduction, and stress response. Dysregulation of the UPS, resulting in loss of ability to maintain protein quality through proteolysis, is closely related to the development of various malignancies and tumorigenesis. Here, we provide a comprehensive general overview on the regulation and roles of UPS and discuss functional links of dysregulated UPS in human malignancies. Inhibitors developed against components of the UPS, which include U.S. Food and Drug Administration FDA-approved and those currently undergoing clinical trials, are also presented in this review.

Metagenomic Sequencing Revealed the Potential Pathogenic Threats of Banknotes

Banknotes have long been suspected to be biologically "dirty" due to their frequent human contact, which may transmit human microbial pathogens. Still, it is an unsettled issue whether the microbes on banknotes pose a real threat to human health. In several previous studies, metagenomic sequencing was used to reveal the diversities of microbes on banknotes but live microorganism culture and functional verification were lacking. In this study, we collected banknotes of RMB in China as well as dollar bills in the United States and analyzed the microbial biodiversity and drug resistance genes carried by the identified microbes by metagenomic sequencing and in vitro culture methods. We identified eight major genera of drug-resistant bacteria through screening of 30 antibiotics, and the blood agar plate culture uncovered six pathogenic fungal species. Numerous phage and six dangerous viral sequences were also found. These results should substantiate our concern about the potential risk of banknotes to human health.

The prognostic value of USP7 and p53 in advanced hypopharyngeal carcinoma

BACKGROUND

Hypopharyngeal squamous cell carcinoma (HPSCC) is a rare malignancy of poor prognosis in head and neck. The aim of the study is to assess the expression and prognostic value of USP7 and p53 in advanced HPSCC.

METHODS

A retrospective study was performed on a cohort of 103 patients with advanced HPSCC. The immunohistochemical expression of USP7 and p53 was evaluated in all the patients, and the prognostic value of USP7 and p53 was further evaluated. Overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS), and local-regional recurrence-free survival (LRFS) were assessed using the Kaplan-Meier method and multivariate Cox regression analysis.

RESULTS

In our study, 78 patients (75.7%) showed low expression of USP7, and the other 25 patients (24.3%) had high expression of USP7; additionally, high USP7 expression was associated with advanced T stage. Low expression of p53 was found in 52 patients (50.5%), while the other 51 patients (49.5%) had a high expression of p53. Our data revealed that low expression of p53 was associated with the advanced N stage (p=0.028). Kaplan-Meier analysis revealed that high expression of USP7 was significantly correlated with the inferior OS, DFS, DMFS, and LRFS, respectively (all p<0.05); additionally, high expression of p53 was correlated with superior OS (p=0.023). The Cox proportional multivariate hazard model revealed that high expression of USP7 was an independent predictor of poor OS, DFS, and LRFS, respectively (all p<0.05).

CONCLUSIONS

Our findings suggest that USP7 combined with p53 are reliable prognostic factors in patients with advanced HPSCC.

Lights and Shadows of TORCH Infection Proteomics

Congenital abnormalities cause serious fetal consequences. The term TORCH is used to designate the most common perinatal infections, where: (T) refers to toxoplasmosis, (O) means "others" and includes syphilis, varicella-zoster, parvovirus B19, zika virus (ZIKV), and malaria among others, (R) refers to rubella, (C) relates to cytomegalovirus infection, and (H) to herpes simplex virus infections. Among the main abnormalities identified in neonates exposed to congenital infections are central nervous system (CNS) damage, microcephaly, hearing loss, and ophthalmological impairment, all requiring regular follow-up to monitor its progression. Protein changes such as mutations, post-translational modifications, abundance, structure, and function may indicate a pathological condition before the onset of the first symptoms, allowing early diagnosis and understanding of a particular disease or infection. The term "proteomics" is defined as the science that studies the proteome, which consists of the total protein content of a cell, tissue or organism in a given space and time, including post-translational modifications (PTMs) and interactions between proteins. Currently, quantitative bottom-up proteomic strategies allow rapid and high throughput characterization of complex biological mixtures. Investigating proteome modulation during host-pathogen interaction helps in elucidating the mechanisms of infection and in predicting disease progression. This "molecular battle" between host and pathogen is a key to identify drug targets and diagnostic markers. Here, we conducted a survey on proteomic techniques applied to congenital diseases classified in the terminology "TORCH", including toxoplasmosis, ZIKV, malaria, syphilis, human immunodeficiency virus (HIV), herpes simplex virus (HSV) and human cytomegalovirus (HCVM). We have highlighted proteins and/or protein complexes actively involved in the infection. Most of the proteomic studies reported have been performed in cell line models, and the evaluation of tissues (brain, muscle, and placenta) and biofluids (plasma, serum and urine) in animal models is still underexplored. Moreover, there are a plethora of studies focusing on the pathogen or the host without considering the triad mother-fetus-pathogen as a dynamic and interconnected system.

Association between herpes simplex virus 1 exposure and the risk of depression in UK Biobank

BACKGROUND

Herpes simplex virus-1 (HSV-1) infection is reported to be associated with depression. But limited efforts were made to investigate the relationship between HSV-1 infection and the risk of depression, especially from the genetic perspective.

METHODS

In UK Biobank cohort, linear and logistic regression analyses were first performed to test the association of HSV-1 seropositivity/antibody with depression, including depression status (N = 2951) and Patient Health Questionnaire (PHQ) score (N = 2839). Using individual genotypic and phenotypic data from the UK Biobank, genome-wide environmental interaction study (GWEIS) was then conducted by PLINK2.0 to evaluate gene × HSV-1 interacting effect on the risk of depression. Finally, gene set enrichment analysis was conducted to identify the biological pathways involved in the observed gene × HSV-1 interaction for depression.

RESULT

In UK Biobank cohort, significant associations were observed between depression status and HSV-1 (odds ratio [OR] = 1.09; 95% confidence interval [CI], 1.02-1.16; P = 2.40 × 10^-2 for HSV-1 antibody and OR = 1.28; 95% CI, 1.12-1.47, P = 2.59 × 10^-3 for HSV-1 seropositivity). GWEIS revealed four significant gene × HSV-1 interaction signals for PHQ score (all P < 5.0 × 10^-8 ) and the leading loci was SULF2 (rs6094791, P = 8.60 × 10^-9 ). Pathway analyses identified 21 pathways for PHQ score and 19 for depression status, including multiple neural development- and immune-related ones, such as KEGG_NEUROACTIVE_LIGAND_RECEPTOR_INTERACTION (false discovery rate [FDR] = 3.18 × 10^-2 ) for depression and LU_AGING_BRAIN_UP (FDR = 4.21 × 10^-2 ) for PHQ score.

CONCLUSION

Our results suggested that HSV-1 was associated with the risk of depression, which was modulated by the several genes that were related to the nerve development or immune function.

The Nuclear Matrix Protein SAFA Surveils Viral RNA and Facilitates Immunity by Activating Antiviral Enhancers and Super-enhancers

Pathogen pattern recognition receptors (PRRs) trigger innate immune responses to invading pathogens. All known PRRs for viral RNA have extranuclear localization. However, for many viruses, replication generates dsRNA in the nucleus. Here, we show that the nuclear matrix protein SAFA (also known as HnRNPU) functions as a nuclear viral dsRNA sensor for both DNA and RNA viruses. Upon recognition of viral dsRNA, SAFA oligomerizes and activates the enhancers of antiviral genes, including IFNB1. Moreover, SAFA is required for the activation of super-enhancers, which direct vigorous immune gene transcription to establish the antiviral state. Myeloid-specific SAFA-deficient mice were more susceptible to lethal HSV-1 and VSV infection, with decreased type I IFNs. Thus, SAFA functions as a nuclear viral RNA sensor and trans-activator to bridge innate sensing with chromatin remodeling and potentiate robust antiviral responses.

Comprehensive Mutagenesis of Herpes Simplex Virus 1 Genome Identifies UL42 as an Inhibitor of Type I Interferon Induction

In spite of several decades of research focused on understanding the biology of human herpes simplex virus 1 (HSV-1), no tool has been developed to study its genome in a high-throughput fashion. Here, we describe the creation of a transposon insertion mutant library of the HSV-1 genome. Using this tool, we aimed to identify novel viral regulators of type I interferon (IFN-I). HSV-1 evades the host immune system by encoding viral proteins that inhibit the type I interferon response. Applying differential selective pressure, we identified the three strongest viral IFN-I regulators in HSV-1. We report that the viral polymerase processivity factor UL42 interacts with the host transcription factor IFN regulatory factor 3 (IRF-3), inhibiting its phosphorylation and downstream beta interferon (IFN-β) gene transcription. This study represents a proof of concept for the use of high-throughput screening of the HSV-1 genome in investigating viral biology and offers new targets both for antiviral therapy and for oncolytic vector design.IMPORTANCE This work is the first to report the use of a high-throughput mutagenesis method to study the genome of HSV-1. We report three novel viral proteins potentially involved in regulating the host type I interferon response. We describe a novel mechanism by which the viral protein UL42 is able to suppress the production of beta interferon. The tool we introduce in this study can be used to study the HSV-1 genome in great detail to better understand viral gene functions.

USP7: Novel Drug Target in Cancer Therapy

Ubiquitin specific protease 7 (USP7) is one of the deubiquitinating enzymes (DUB) that erases ubiquitin and protects substrate protein from degradation. Full activity of USP7 requires the C-terminal Ub-like domains fold back onto the catalytic domain, allowing the remodeling of the active site to a catalytically competent state by the C-terminal peptide. Until now, numerous proteins have been identified as substrates of USP7, which play a key role in cell cycle, DNA repair, chromatin remodeling, and epigenetic regulation. Aberrant activation or overexpression of USP7 may promote oncogenesis and viral disease, making it a target for therapeutic intervention. Currently, several synthetic small molecules have been identified as inhibitors of USP7, and applied in the treatment of diverse diseases. Hence, USP7 may be a promising therapeutic target for the treatment of cancer.

A novel glycoprotein D-specific monoclonal antibody neutralizes herpes simplex virus

The worldwide prevalence of herpes simplex virus (HSV) and the shortage of efficient vaccines and novel therapeutic strategies against HSV are widely global concerns. The abundance on the virion and the major stimulus for the virus-neutralizing antibodies makes gD a predominant candidate for cure of HSV infection. In this study, we generated a monoclonal antibody (mAb), termed m27f, targeting to glycoprotein D (gD) of HSV-2, which also has cross-reactivity against HSV-1 gD. It has a high level of neutralizing activity against both HSV-1 and HSV-2, and binds to a highly conserved region (residues 292-297) within the pro-fusion domain of gD. It can effectively block HSV cell-to-cell spread in vitro. The pre- or post-attachment neutralization assay and syncytium formation inhibition assay revealed that m27f neutralizes HSV at the post-binding stage. Moreover, therapeutic administration of m27f completely prevented infection-related mortality of mice challenged with a lethal dose of HSV-2. Our newly identified epitope for the neutralizing antibody would facilitate studies of gD-based HSV entry or vaccine design, and m27f itself demonstrated a high potential for adaptation as a protective or therapeutic drug against HSV.

Regulable Transgene Expression in Dorsal Root Ganglia of a Replication-Defective Herpes Simplex Virus Type 1 Vector by Means of Sciatic Nerve Injection

BACKGROUND

Targeted and controllable gene delivery to neurons is essential to efforts to facilitate peripheral nerve regeneration. The authors investigated both the in vitro and in vivo expression profiles of a tetracycline-controlled, replication-defective, herpes simplex virus type 1-based vector.

METHODS

Mouse primary dorsal root ganglia cells were infected with QR9TO-LacZ in the absence or presence of tetracycline. LacZ gene expression was examined. It was also injected into sciatic nerves in CD-1 mice fed with and without tetracycline. LacZ expression in the upstream dorsal root ganglia was examined.

RESULTS

Following inoculation with QR9TO-LacZ, approximately 40 percent of the cultured primary dorsal root ganglia cells exhibited strong LacZ activity in the presence of tetracycline at 48 and 72 hours, whereas little was detected in those in the absence of tetracycline. Quantitative analysis revealed that the β-galactosidase activity within cells exposed to tetracycline increased 181-fold at 48 hours (p < 0.001) and 47-fold at 72 hours after infection (p < 0.05) compared with those without tetracycline. However, this LacZ transgene activity in the presence of tetracycline tapered off to less than sevenfold over baseline 168 hours after infection (p < 0.05). Furthermore, successful uptake of this replication-defective viral vector was evident in upstream dorsal root ganglia after sciatic nerve injection in mice. In addition, its expression profile was similar to that in vitro, as strong β-galactosidase activity was evident only in mice fed with a doxycycline-containing diet, and it tapered off by 168 hours.

CONCLUSION

The replication-defective herpes simplex virus type 1-based vector, which provides tightly regulated transgene expression in dorsal root ganglia by means of peripheral nerve injection, represents an appealing approach to improve peripheral nerve regeneration.

In search for effective and definitive treatment of herpes simplex virus type 1 (HSV-1) infections

Herpes Simplex Virus type 1 (HSV-1) is a nuclear replicating enveloped virus.