Harmol used for the treatment of herpes simplex virus induced keratitis.

Herpes simplex virus type 1 (HSV-1) infection of the eyes results in herpes simplex keratitis (HSK), which has led to vision loss and even blindness in patients. However, the rate of drug resistance in HSV is on the rise; therefore, new antiviral agents with sufficient safety profiles must be developed. At present, we assessed the anti-HSV-1 activity of 502 natural compounds and their ability to reduce the HSV-1-induced cytopathic effect. We chose harmol for further studies because it exhibited the highest antiviral activity. We found that harmol inhibited both HSV-1 F and HSV-1/153 (a clinical drug-resistant strain) replication, with an EC50 of 9.34 µM and 5.84 µM, respectively. Moreover, harmol reduced HSV-1 replication in corneal tissues and viral progeny production in tears, and also alleviated early corneal surface lesions related to HSK. For example, harmol treatment preserved corneal thickness and nerve density in HSK mice. Interestingly, harmol also showed a promising antiviral effect on HSV-1/153 induced HSK in mouse model. Furthermore, harmol combined with acyclovir (ACV) treatment showed a greater antiviral effect than either one alone in vitro. Therefore, harmol may be a promising therapeutic agent for managing HSK.

HSV-1 immune escapes in microglia by down-regulating GM130 to inhibit TLR3-mediated innate immune responses.

BACKGROUND: To investigate the mechanism of Golgi matrix protein 130(GM130) regulating the antiviral immune response of TLR3 after herpes simplex virus type 1(HSV-1) infection of microglia cells. We explored the regulatory effects of berberine on the immune response mediated by GM130 and TLR3. METHODS: An in vitro model of HSV-1 infection was established by infecting BV2 cells with HSV-1. RESULTS: Compared to the uninfected group, the Golgi apparatus (GA) fragmentation and GM130 decreased after HSV-1 infection; TLR3 increased at 6 h and began to decrease at 12 h after HSV-1 infection; the secretion of interferon-beta(IFN-ß), tumour necrosis factor alpha(TNF-α), and interleukin-6(IL-6) increased after infection. Knockdown of GM130 aggravated fragmentation of the GA and caused TLR3 to further decrease, and the virus titer also increased significantly. GM130 knockdown inhibits the increase in TLR3 and inflammatory factors induced by TLR3 agonists and increases the viral titer. Overexpression of GM130 alleviated fragmentation of the GA induced by HSV-1, partially restored the levels of TLR3, and reduced viral titers. GM130 overexpression reversed the reduction in TLR3 and inflammatory cytokine levels induced by TLR3 inhibitors. Therefore, the decrease in GM130 levels caused by HSV-1 infection leads to increased viral replication by inhibiting TLR3-mediated innate immunity. Berberine can protect the GA and reverse the downregulation of GM130, as well as the downregulation of TLR3 and its downstream factors after HSV-1 infection, reducing the virus titer. CONCLUSIONS: In microglia, one mechanism of HSV-1 immune escape is disruption of the GM130/TLR3 pathway. Berberine protects the GA and enhances TLR3-mediated antiviral immune responses.

Immunogenicity and protective efficacy of a recombinant lactococcus lactis vaccine against HSV-1 infection.

BACKGROUND: Herpes simplex virus type 1 (HSV-1) is a major cause of viral encephalitis, genital mucosal infections, and neonatal infections. Lactococcus lactis (L. lactis) has been proven to be an effective vehicle for delivering protein antigens and stimulating both mucosal and systemic immune responses. In this study, we constructed a recombinant L. lactis system expressing the protective antigen glycoprotein D (gD) of HSV-1. RESULTS: To improve the stability and persistence of antigen stimulation of the local mucosa, we inserted the immunologic adjuvant interleukin (IL)-2 and the Fc fragment of IgG into the expression system, and a recombinant L. lactis named NZ3900-gD-IL-2-Fc was constructed. By utilizing this recombinant L. lactis strain to elicit an immune response and evaluate the protective effect in mice, the recombinant L. lactis vaccine induced a significant increase in specific neutralizing antibodies, IgG, IgA, interferon-γ, and IL-4 levels in the serum of mice. Furthermore, in comparison to the mice in the control group, the vaccine also enhanced the proliferation levels of lymphocytes in response to gD. Moreover, recombinant L. lactis expressing gD significantly boosted nonspecific immune reactions in mice through the activation of immune-related genes. Furthermore, following the HSV-1 challenge of the murine lung mucosa, mice inoculated with the experimental vaccine exhibited less lung damage than control mice. CONCLUSION: Our study presents a novel method for constructing a recombinant vaccine using the food-grade, non-pathogenic, and non-commercial bacterium L. lactis. The findings indicate that this recombinant vaccine shows promise in preventing HSV-1 infection in mice.

Development of an HSV-1 production process involving serum-reduced culturing and bead-to-bead transfer.

Herpes simplex virus type 1 (HSV-1) plays an important role in the field of gene therapy and viral vaccines, especially as an oncolytic virus. However, the mass production of HSV-1 viral vectors remains a challenge in the industry. In this study, a microcarrier-mediated serum-reduced medium culture was used to improve the bioprocess of HSV-1 production and increase HSV-1 yields. The composition of the culture media, which included a basal medium, serum concentration, and glutamine additive, was optimized. The process was successfully conducted in a 1 L bioreactor, and virus production was threefold greater than that of conventional processes with a 10% serum medium. The bead-to-bead transfer process was also developed to further increase scalability. In spinner flasks, the detachment rate increased from 49.4 to 80.6% when combined agitation was performed during digestion; the overall recovery proportion increased from 37.9 to 71.1% after the operational steps were optimized. Specifically, microcarrier loss was reduced during aspiration and transfer, and microcarriers and detached cells were separated with filters. Comparable cell growth was achieved with the baseline process using 2D culture as the inoculum by exchanging the subculture medium. To increase virus production after bead-to-bead transfer, critical parameters, including shear stress during digestion, TrypLE and EDTA concentrations in the subculture, and the CCI, were identified from 47 parameters via correlation analysis and principal component analysis. The optimized bead-to-bead transfer process achieved an average of 90.4% overall recovery and comparable virus production compared to that of the baseline process. This study is the first to report the optimization of HSV-1 production in Vero cells cultured on microcarriers in serum-reduced medium after bead-to-bead transfer. KEY POINTS: • An HSV-1 production process was developed that involves culturing in serum-reduced medium, and this process achieved threefold greater virus production than that of traditional processes. • An indirect bead-to-bead transfer process was developed with over 90% recovery yield in bioreactors. • HSV-1 production after bead-to-bead transfer was optimized and was comparable to that achieved with 2D culture as inoculum.

Dupilumab strengthens herpes simplex virus type 1-specific immune responses in atopic dermatitis.

BACKGROUND: Impaired virus clearance in a subgroup of atopic dermatitis (AD) patients can lead to severe herpes simplex virus (HSV) infections called eczema herpeticum (EH). We recently identified a type 2 skewed viral immune response in EH patients. Clinical data suggest a reduced incidence of EH in AD patients treated with dupilumab, although immunologic investigations of this phenomenon are still lacking. OBJECTIVE: We examined the impact of dupilumab on the HSV type 1 (HSV-1) specific immune response in AD, focusing on patients with (ADEH+) and without (ADEH-) a history of EH. METHODS: Sera and peripheral blood mononuclear cells were collected from ADEH+ and ADEH- patients, a subgroup of whom was receiving dupilumab treatment, and healthy controls. Serum samples were tested for IgE against HSV-1 glycoprotein D (n = 85). Peripheral blood mononuclear cells were stimulated with HSV peptides, and activated CD4+ and CD8+ cells were characterized by flow cytometry after magnetic enrichment via CD154 or CD137 (n = 60). Cytokine production of HSV-1-reactive T-cell lines (n = 33) and MHC-I tetramer+ (HSV-1-UL25) CD8+ T cells was investigated by bead assay and intracellular cytokine staining (n = 21). RESULTS: We confirmed that HSV-1-specific IgE is elevated in ADEH+ patients. During dupilumab treatment, the IgE levels were significantly decreased, reaching levels of healthy controls. HSV-1-specific TC1 frequencies were elevated in ADEH- patients treated with dupilumab compared to dupilumab-negative patients. There were no changes in the frequencies of HSV-1-specific TH cells while receiving dupilumab therapy. AD patients receiving dupilumab exhibited elevated IFN-γ and reduced IL-4 production in HSV-1-UL25-epitope-specific T cells compared to dupilumab-negative patients. CONCLUSION: Dupilumab may improve the HSV-1-specific immune response in AD as a result of an increased type I immune response and a reduction of HSV-1-specific IgE.

Vaginal Lactobacilli Supernatants Protect from Herpes Simplex Virus Type 1 Infection in Cell Culture Models.

A healthy vaginal microbiota hosts Lactobacillus as the most predominant genus. Lactobacilli play a role in human health through the production of diverse antimicrobial substances that can act against human pathogens or modulate the immune system. Previous reports highlighted the ability of vaginal lactobacilli to counteract viruses causing STIs, e.g., HIV-1 and HSV-2. In this report, we analyze the activity of supernatants of vaginal lactobacilli against HSV-1 infection, which is becoming increasingly relevant as a STI. We show that the supernatants of two vaginal Lactobacillus species (i.e., L. crispatus and L. gasseri) were active at neutralizing HSV-1 infection in two different cell lines of human and simian origin. Specifically, we demonstrate that L. crispatus strains are the most effective in antiviral activity, as evidenced by the comparison with a vaginal pathogen taken as reference. The effect was specific and not attributable to the generic toxicity of the supernatants to the cells. Our results pave the way for the development of probiotics to limit the impact of HSV-1 infection on women's health.

Combined Effect of Basic Antiherpetic Drugs with a New Inhibitor of the Terminase Complex of Herpes Simplex Virus Type 1 in Vero Cell Cultures.

Carriers of herpes simplex virus type 1 (HSV-1) account for more than 90% of the global population. Infection manifests itself in the formation of blisters and ulcers on the face or genitals and can cause blindness, encephalitis, and generalized infection. All first- and second-line modern antiherpetic drugs selectively inhibit viral DNA polymerase. The purine-benzoxazine conjugate LAS-131 ((S)-4-[6-(purin-6-yl)aminohexanoyl]-7,8-difluoro-3,4-dihydro-3-methyl-2H-[1,4]benzoxazine), which we have described earlier, uses the large subunit of the HSV-1 terminase complex as a biotarget and selectively inhibits HSV-1 reproduction in vitro. Basically new results were for the first time obtained to characterize the combined effect on human herpesvirus infection for LAS-131 used in combination with practically significant antiviral compounds, including the nucleoside analogs acyclovir (ACV), penciclovir (PCV), ganciclovir (GCV), brivudine (BVdU), iododeoxyuridine (IdU), and adenine arabinoside (Ara-A); the nucleoside phosphonate analog cidofovir (CDV); and the pyrophosphate analog foscarnet (FOS). A cytopathic effect (CPE) inhibition assay showed that the drug concentration that inhibited the virus-induced CPE by 50% decreased by a factor of 2 (an additive effect, FOS) or more (a synergistic effect; ACV, PCV, GCV, IdU, BVdU, Ara-A, and CDV) when the drugs were used in combination with LAS-131. Nonpermissive conditions for HSV-1 reproduction were thus created at lower drug concentrations, opening up new real possibilities to control human herpesvirus infection.

Association between human genetic variants affecting the host NK cell response and the development of herpes simplex virus type 1 encephalitis.

Herpes simplex virus encephalitis (HSE) is a rare complication of herpes simplex virus type 1 (HSV-1) infection or reactivation. It is so far unclear why only few patients develop HSE. As natural killer (NK) cells provide an important defense against HSV-1, we investigated whether there is an association between distinct human genetic variants associated with the host NK cell response and HSE. Forty-nine adult patients with confirmed HSE and 247 matched controls were analyzed for the distribution of the following genotypes: CD16A (FcγRIIIA) V/F and IGHG1 G1m3/17, both influencing antibody-dependent cellular cytotoxicity; HLA-E*0101/*0103, associated with NK cell activation; and SLFN13 rs9916629C/T  associated with NK cell response. Homozygous HLA-E*0101:0101 and HLA-E*0103:0103 variants as well as the rs9916629CC genotype were overrepresented in HSE patients compared to controls (p ≤ 0.001). Notably, cooccurrence of the homozygous HLA-E*0101 and rs9916629CC genotypes was present in 19% of patients but totally absent in controls (p ≤ 0.0001). Distribution of CD16A and IGHG1 variants did not differ between patients and controls. Our data show that the rare combination of HLA-E*0101:0101 and rs9916629CC is significantly associated with HSE. Possibly, these genetic variations could be useful as clinical markers predicting HSE prognosis and helping to adapt the treatment of HSE in the individual patient.

HSV-1 infection-induced herpetic neuralgia involves a CCL5/CCR5-mediated inflammation mechanism.

Herpetic-related neuralgia (HN) caused by varicella-zoster virus (VZV) infection is one of the most typical and common neuropathic pain in the clinic. However, the potential mechanisms and therapeutic approaches for the prevention and treatment of HN are still unclear. This study aims to provide a comprehensive understanding of the molecular mechanisms and potential therapeutic targets of HN. We used an HSV-1 infection-induced HN mouse model and screened the differentially expressed genes (DEGs) in the DRG and spinal cord using an RNAseq technique. Moreover, bioinformatics methods were used to figure out the signaling pathways and expression regulation patterns of the DEGs enriched. In addition, quantitative real-time RT-PCR and western blot were carried out to further confirm the expression of DEGs. HSV-1 inoculation in mice resulted in mechanical allodynia, thermal hyperalgesia, and cold allodynia, following the infection of HSV-1 in both DRG and spinal cord. Besides, HSV-1 inoculation induced an up-regulation of ATF3, CGRP, and GAL in DRG and activation of astrocytes and microglia in the spinal cord. Moreover, 639 genes were upregulated, 249 genes were downregulated in DRG, whereas 534 genes were upregulated and 12 genes were downregulated in the spinal cord of mice 7 days after HSV-1 inoculation. GO and KEGG enrichment analysis suggested that immune responses and cytokine-cytokine receptor interaction are involved in DRG and spinal cord neurons in mice after HSV-1 infection. In addition, CCL5 and its receptor CCR5 were significantly upregulated in DRG and spinal cord upon HSV-1 infection in mice. And blockade of CCR5 exhibited a significant analgesic effect and suppressed the upregulation of inflammatory cytokines in DRG and spinal cord induced by HSV-1 infection in mice. HSV-1 infection-induced allodynia and hyperalgesia in mice through dysregulation of immune response and cytokine-cytokine receptor interaction mechanism. Blockade of CCR5 alleviated allodynia and hyperalgesia probably through the suppression of inflammatory cytokines. Therefore, CCR5 could be a therapeutic target for the alleviation of HSV-1 infection-induced HN.

HSV-1 latency-associated transcript miR-H3 and miR-H4 target STXBP1 and GABBR2 genes.

During latent infection, the HSV-1 virus generates only a single transcript, LAT, which encodes six miRNAs. The GABAergic pathway signaling system is an essential cell signaling pathway influenced by various therapeutic targets and some brain disorders, such as epilepsy. This study found that miRNAs encoding LAT might target the STXBP1 and GABBR2 genes, which are among the significant genes in the GABAergic pathway. Bioinformatic analysis utilizing TargetScan version 5.2 and the RNA22 tools uncovered miRNAs encoding LAT that can influence STXBP1 and GABBR2 transcripts. To evaluate the targeting effect of candidate microRNAs encoding LAT, namely, miR-H3 and miR-H4, LAT constructs were transfected into HEK 293T cells. The expression levels of microRNAs encoding LAT, as well as STXBP1 and GABBR2, were assayed by real-time PCR. Finally, the targeting potential of STXBP1 and GABBR2 3'UTR by LAT-encoded microRNAs was evaluated by the luciferase assay. In the current study, the bioinformatic tool TargetScan demonstrated that miR-H3 has the potential to target the transcripts of the STXBP1 and GABBR2 genes, whereas miR-H4 solely targeted GABBR2. On the other hand, the bioinformatic tool RNA22 validated the potential targeting of STXBP1 and GABBR2 by miR-H3 and miR-H4. Our findings showed that overexpression of miR-H4, miR-H3, or LAT significantly decreased STXBP1 gene expression by an average of 0.0593-fold, 0.237-fold, and 0.84-fold, respectively. Similarly, overexpression of miR-H3 or miR-H4 decreased GABBR2 expression by an average of 0.055- or 0.687-fold, respectively. Notably, targeting the GABBR2 3'UTR with the LAT transcript had no detectable effect. The evaluation of the targeting potential of STXBP1 and GABBR2 3'UTR by microRNAs encoded by LAT was conducted with a luciferase assay. Our results showed that miR-H3 overexpression reduces Renilla expression in psiCHECK2 plasmids with STXBP1 or GABBR2 3'UTR genes by 0.62- and 0.55-fold, respectively. miR-H4 reduced Renilla gene expression regulated by GABBR2's 3'UTR plasmid but had no effect on the Renilla gene expression regulated by STXBP1's 3'UTR. When the LAT transcript was overexpressed, there was a decrease in Renilla expression by 0.44-fold because of the regulation of STXBP1's 3'UTR. However, there was no significant effect observed through the control of GABBR2's 3'UTR.

Fatal Simplexvirus humanalpha1 infection in howler-monkeys (Alouatta sp.) under human care: Clinical, molecular, and pathological findings.

BACKGROUND: Simplexvirus humanalpha1 (HuAHV-1) are common anthropozoonosis reported in marmosets but rare in howler monkeys (Alouatta sp.). METHODS: Necropsy of two brown-howler monkeys (A. caraya) and one red-howler monkey (A. guariba clamitans) from different zoo collections were performed. Fragments of all organs were examined through microscopy. Samples were submitted to IHC for Simplexvirus humanalpha 2 (HuAHV-2) [sin. Herpesvirus simplex type 2] and PCR. RESULTS: Grossly, only the A. guariba showed liver lesions characterized by multifocal, pinpoint white areas corresponding microscopically as random necrotizing herpetic hepatitis and ulcerative glossitis. Both A. caraya showed necrotizing meningoencephalitis with Cowdry A-type body inclusions within neurons and astrocytes. Immunolabeling for HuAHV-1/2 was observed in the tongue, liver, and brain. HuAHV-1 was confirmed in all samples by PCR, Sanger sequencing, and phylogenetic analyses. CONCLUSION: Necrotizing meningoencephalitis was appreciated in 2/3 of animals, and it is associated with neurologic signs. Along with ulcerative glossitis, a hallmark lesion in marmosets, it was present in one animal. Regarding herpetic hepatitis, it is not frequent in monkeys and occurs mainly in immunocompromised animals. HuAHV-1 infection was confirmed corroborating with a human source. This is the second report on captive black-howler monkeys and the first gross, histologic, immunohistochemical, and molecular description of herpetic hepatitis and ulcerative glossitis in red-howler monkeys (A. guariba).

The possibility of spreading herpes simplex virus type 1 via food handling and sharing.

AIMS: Herpes simplex virus type 1 (HSV-1) is an enveloped virus that causes recurrent and incurable diseases in 67% of the world population. Although it is not listed as a foodborne virus, some studies have shown that it can be recovered from surfaces as well as food. METHODS AND RESULTS: We investigated its persistence at -20°C, 4°C, 20°C, or 37°C for up to 7 days on stainless steel, aluminum, glass, polypropylene, cheddar cheese, sliced almond, and apple skin and in cola soft drink, orange juice, coffee, and milk, as well as its transferability from stainless steel to dry or moistened nitrile or latex gloves over time at typical ambient temperatures. Based on the plaque assay on Vero cells, HSV-1 persisted at least 24 h on all surfaces and at least 1 h on food matrices but was inactivated quickly in cola soft drink. Temperature and pH affected HSV-1 infectivity. Transfer of HSV-1 at a contact pressure of 1 kg cm2-1 for 10 s occurred only on latex, especially moistened. CONCLUSIONS: Our data on the persistence of HSV-1 on food-related surfaces suggest that some risk may be associated with sharing foods with infected carriers.

Reducing lipid peroxidation attenuates stress-induced susceptibility to herpes simplex virus type 1.

Psychological stress increases the susceptibility to herpes simplex virus type 1 (HSV-1) infection. There is no effective intervention due to the unknown pathogenesis mechanisms. In this study we explored the molecular mechanisms underlying stress-induced HSV-1 susceptibility and the antiviral effect of a natural compound rosmarinic acid (RA) in vivo and in vitro. Mice were administered RA (11.7, 23.4 mg·kg-1·d-1, i.g.) or acyclovir (ACV, 206 mg·kg-1·d-1, i.g.) for 23 days. The mice were subjected to restraint stress for 7 days followed by intranasal infection with HSV-1 on D7. At the end of RA or ACV treatment, mouse plasma samples and brain tissues were collected for analysis. We showed that both RA and ACV treatment significantly decreased stress-augmented mortality and alleviated eye swelling and neurological symptoms in HSV-1-infected mice. In SH-SY5Y cells and PC12 cells exposed to the stress hormone corticosterone (CORT) plus HSV-1, RA (100 µM) significantly increased the cell viability, and inhibited CORT-induced elevation in the expression of viral proteins and genes. We demonstrated that CORT (50 µM) triggered lipoxygenase 15 (ALOX15)-mediated redox imbalance in the neuronal cells, increasing the level of 4-HNE-conjugated STING, which impaired STING translocation from the endoplasmic reticulum to Golgi; the abnormality of STING-mediated innate immunity led to HSV-1 susceptibility. We revealed that RA was an inhibitor of lipid peroxidation by directly targeting ALOX15, thus RA could rescue stress-weakened neuronal innate immune response, thereby reducing HSV-1 susceptibility in vivo and in vitro. This study illustrates the critical role of lipid peroxidation in stress-induced HSV-1 susceptibility and reveals the potential for developing RA as an effective intervention in anti-HSV-1 therapy.

Evaluation of the effects of herpes simplex glycoprotein B on complement system and cytokines in in vitro models of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder that causes memory loss and dementia and is characterized by a decline in cognitive functions. Brain infections, especially induced by herpes simplex virus type-1 (HSV-1), are suggested to play a key role in the pathogenesis of AD. Within the scope of this study, two different AD models (Tau model and amyloid beta [Aß]) were created in the SH-SY5Y cell line, and HSV glycoprotein B (gB) was applied to the cell line and on the generated AD models. Study groups (n = 3) were designed as (1) control, (2) HSV-gB group, (3) retinoic acid (RA) and brain derived neurotrophic factor (BDNF) induced Alzheimer's model (AD), (4) RA and BDNF induced Alzheimer's model + HSV-gB (ADH), (5) Aß 1-42 peptide-induced Alzheimer's model (Aß), and (6) Aß 1-42 peptide-induced Alzheimer's model + HSV-gB (AßH). Levels of complement proteins and cytokines were determined comparatively. In addition, specific markers of AD (hyperphosphorylated Tau proteins, Aß 1-40 peptide and amyloid precursor protein) were measured in all groups. HSV-gB administration was found to increase Aß and hyperphosphorylated Tau levels, similar to AD models. In addition, our data confirmed that the immune system and chronic inflammation might have a crucial role in AD development and that HSV-1 infection might also be an underlying factor of AD.

Infections, Vaccinations, and Risk of Alzheimer's Disease (AD)/Dementia: Probable Involvement of Reactivated Herpes Simplex Virus Type 1.

Infections are associated with cognitive decline and increased risk of AD/dementia (Sochocka M, Zwolinska K, Leszek J. Curr Neuropharmacol 15:996-1009, 2017; Ou YN, Zhu JX, Hou XH, Shen XN, Xu W, Dong Q, et al. J Alzheimers Dis 75:299-309, 2020; Sipilä PN, Heikkilä N, Lindbohm JV, Hakulinen C, Vahtera J, Elovainio M, et al. Lancet Infect Dis 21:1557-1567, 2021; Damiano RF, Guedes BF, de Rocca CC, de Padua Serafim A, Castro LHM, Munhoz CD, et al. Eur Arch Psychiatry Clin Neurosci 272:139-154, 2022), and some studies have shown that vaccinations, such as BCG, against a variety of infections decrease the risk. Several reports have described an association of varicella zoster virus (VZV) with AD, and in an epidemiological study, we found that shingles, a disease caused by VZV, conferred a small increased AD/dementia risk, while vaccination against the disease led to a greatly decreased risk - subsequently confirmed by others (Lophatananon A, Mekli K, Cant R, Burns A, Dobson C, Itzhaki R, Muir K, BMJ Open 11:e045871, 2021a; Lehrer S, Rheinstein PH. In Vivo 35:3271-3275, 2021; Scherrer JF, Salas J, Wiemken TL, Hoft DF, Jacobs C, Morley JE. PLoS One 16:e0257405, 2021).

Metabolomics Profiles Reveal New Insights of Herpes Simplex Virus Type 1 Infection.

Herpes simplex virus type 1 (HSV-1) is a ubiquitous human pathogen that can cause significant morbidity, primarily facial cold sores and herpes simplex encephalitis. Previous studies have shown that a variety of viruses can reprogram the metabolic profiles of host cells to facilitate self-replication. In order to further elucidate the metabolic interactions between the host cell and HSV-1, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to analyze the metabolic profiles in human lung fibroblasts KMB17 infected with HSV-1. The results showed that 654 and 474 differential metabolites were identified in positive and negative ion modes, respectively, and 169 and 114 metabolic pathways that might be altered were screened. These altered metabolites are mainly involved in central carbon metabolism, choline metabolism, amino acid metabolism, purine and pyrimidine metabolism, cholesterol metabolism, bile secretion, and prolactin signaling pathway. Further, we confirmed that the addition of tryptophan metabolite kynurenine promotes HSV-1 replication, and the addition of 25-Hydroxycholesterol inhibits viral replication. Significantly, HSV-1 replication was obviously enhanced in the ChOKα (a choline metabolic rate-limiting enzyme) deficient mouse macrophages. These results indicated that HSV-1 induces the metabolic reprogramming of host cells to promote or resist viral replication. Taken together, these observations highlighted the significance of host cell metabolism in HSV-1 replication, which would help to clarify the pathogenesis of HSV-1 and identify new anti-HSV-1 therapeutic targets.

The Dilemma of HSV-1 Oncolytic Virus Delivery: The Method Choice and Hurdles.

Oncolytic viruses (OVs) have emerged as effective gene therapy and immunotherapy drugs. As an important gene delivery platform, the integration of exogenous genes into OVs has become a novel path for the advancement of OV therapy, while the herpes simplex virus type 1 (HSV-1) is the most commonly used. However, the current mode of administration of HSV-1 oncolytic virus is mainly based on the tumor in situ injection, which limits the application of such OV drugs to a certain extent. Intravenous administration offers a solution to the systemic distribution of OV drugs but is ambiguous in terms of efficacy and safety. The main reason is the synergistic role of innate and adaptive immunity of the immune system in the response against the HSV-1 oncolytic virus, which is rapidly cleared by the body's immune system before it reaches the tumor, a process that is accompanied by side effects. This article reviews different administration methods of HSV-1 oncolytic virus in the process of tumor treatment, especially the research progress in intravenous administration. It also discusses immune constraints and solutions of intravenous administration with the intent to provide new insights into HSV-1 delivery for OV therapy.

Synthetic Heparanase Inhibitors Can Prevent Herpes Simplex Viral Spread.

Herpes simplex virus (HSV-1) employs heparan sulfate (HS) as receptor for cell attachment and entry. During late-stage infection, the virus induces the upregulation of human heparanase (Hpse) to remove cell surface HS allowing viral spread. We hypothesized that inhibition of Hpse will prevent viral release thereby representing a new therapeutic strategy for HSV-1. A range of HS-oligosaccharides was prepared to examine the importance of chain length and 2-O-sulfation of iduronic moieties for Hpse inhibition. It was found that hexa- and octasaccharides potently inhibited the enzyme and that 2-O-sulfation of iduronic acid is tolerated. Computational studies provided a rationale for the observed structure-activity relationship. Treatment of human corneal epithelial cells (HCEs) infected with HSV-1 with the hexa- and octasaccharide blocked viral induced shedding of HS which significantly reduced spread of virions. The compounds also inhibited migration and proliferation of immortalized HCEs thereby providing additional therapeutic properties.

Herpes Simplex Virus 1 Coinfection Modifies Adeno-associated Virus Genome End Recombination.

Wild-type adeno-associated virus (AAV) can only replicate in the presence of helper factors, which can be provided by coinfecting helper viruses such as adenoviruses and herpesviruses. The AAV genome consists of a linear, single-stranded DNA (ssDNA), which is converted into different molecular structures within the host cell. Using high-throughput sequencing, we found that herpes simplex virus 1 (HSV-1) coinfection leads to a shift in the type of AAV genome end recombination. In particular, open-end inverted terminal repeat (ITR) recombination was enhanced, whereas open-closed ITR recombination was reduced in the presence of HSV-1. We demonstrate that the HSV-1 protein ICP8 plays an essential role in HSV-1-mediated interference with AAV genome end recombination, indicating that the previously described ICP8-driven mechanism of HSV-1 genome recombination may be underlying the observed changes. We also provide evidence that additional factors, such as products of true late genes, are involved. Although HSV-1 coinfection significantly changed the type of AAV genome end recombination, no significant change in the amount of circular AAV genomes was identified. IMPORTANCE Adeno-associated virus (AAV)-mediated gene therapy represents one of the most promising approaches for the treatment of genetic diseases. Currently, various GMP-compatible production methods can be applied to manufacture clinical-grade vector, including methods that employ helper factors derived from herpes simplex virus 1 (HSV-1). Yet, to date, we do not fully understand how HSV-1 interacts with AAV. We observed that HSV-1 modulates AAV genome ends similarly to the genome recombination events observed during HSV-1 replication and postulate that further improvements of the HSV-1 production platform may enhance packaging of the recombinant AAV particles.

Upregulation of nuclear factor E2-related factor 2 (Nrf2) represses the replication of herpes simplex virus type 1.

BACKGROUND: Nuclear factor E2-related factor 2 (Nrf2) is an important transcription factor which plays a pivotal role in detoxifying reactive oxygen species (ROS) and has been more recently shown to regulate inflammatory and antiviral responses. However, the role of Nrf2 in Herpes Simplex Virus type 1 (HSV-1) infection is still unclear. In this study, the interaction between the Nrf2 and HSV-1 replication was investigated. METHODS: The levels of oxidative stress was monitored by using 8-hydroxy-2'-deoxyguanosine (8-OHdG) ELISA kits, and the dynamic changes of Nrf2-antioxidant response element (Nrf2-ARE) pathway were detected by Western Blot. The effect of Nrf2-ARE pathway on the regulation of HSV-1 proliferation was analyzed by Western Blot, Real-Time PCR and TCID50 assay. RESULTS: HSV-1 infection induced oxidative stress. Nrf2 was activated, accompanied by the increase of its down-stream antioxidant enzyme heme oxygenase-1 (HO-1) and NAD(P)H quinone oxidoreductase 1 (NQO1) in the early stage of HSV-1 infection. The proliferation of HSV-1 was inhibited by overexpression of Nrf2 or treatment with its activator tert-Butylhydroquinone (tBHQ). On the contrary, silencing of Nrf2 promotes virus replication. HO-1 is involved in the regulation of IFN response, leading to efficient anti-HSV-1 effects. CONCLUSION: Our observations indicate that the Nrf2-ARE pathway activates a passive defensive response in the early stage of HSV-1 infection. Targeting the Nrf2 pathway demonstrates the potential for combating HSV-1 infection.