Herpes Simplex Virus Type 1 Infection Research Articles

Heparanase 2 Modulation Inhibits HSV-2 Replication by Regulating Heparan Sulfate

The host enzyme heparanase (HPSE) facilitates the release of herpes simplex virus type 2 (HSV-2) from target cells by cleaving the viral attachment receptor heparan sulfate (HS) from infected cell surfaces. HPSE 2, an isoform of HPSE, binds to but does not possess the enzymatic activity needed to cleave cell surface HS. Our study demonstrates that HSV-2 infection significantly elevates HPSE 2 protein levels, impacting two distinct stages of viral replication. We show that higher HPSE 2 negatively affects HSV-2 replication which may be through the regulation of cell surface HS. By acting as a competitive inhibitor of HPSE, HPSE 2 may be interfering with HPSE’s interactions with HS. We demonstrate that the enhanced expression of HPSE 2, either via viral infection or plasmid transfection, reduces HPSE’s ability to cleave HS, thereby hindering viral egress. Conversely, low HPSE 2 levels achieved through siRNA transfection allow HPSE to cleave more HS, reducing viral entry. Altogether, we propose a hypothetical model in which the modulation of HPSE 2 impedes HSV-2 replication by regulating HS availability on the cell surface. This dual role of HPSE 2 in viral replication and potential tumor suppression underscores its significance in cellular processes and viral pathogenesis.

Cryptic phosphoribosylase activity of NAMPT restricts the virion incorporation of viral proteins.

As obligate intracellular pathogens, viruses activate host metabolic enzymes to supply intermediates that support progeny production. Nicotinamide phosphoribosyltransferase (NAMPT), the rate-limiting enzyme of salvage nicotinamide adenine dinucleotide (NAD+) synthesis, is an interferon-inducible protein that inhibits the replication of several RNA and DNA viruses through unknown mechanisms. Here, we show that NAMPT restricts herpes simplex virus type 1 (HSV-1) replication by impeding the virion incorporation of viral proteins owing to its phosphoribosyl-hydrolase (phosphoribosylase) activity, which is independent of the role of NAMPT in NAD+ synthesis. Proteomics analysis of HSV-1-infected cells identifies phosphoribosylated viral structural proteins, particularly glycoproteins and tegument proteins, which are de-phosphoribosylated by NAMPT in vitro and in cells. Chimeric and recombinant HSV-1 carrying phosphoribosylation-resistant mutations show that phosphoribosylation promotes the incorporation of structural proteins into HSV-1 virions and subsequent virus entry. Loss of NAMPT renders mice highly susceptible to HSV-1 infection. Our work describes an additional enzymatic activity of a metabolic enzyme in viral infection and host defence, offering a system to interrogate the roles of protein phosphoribosylation in metazoans.

Control of HSV-1 Infection: Directions for the Development of CRISPR/Cas-Based Therapeutics and Diagnostics.

It is estimated that nearly all individuals have been infected with herpesviruses, with herpes simplex virus type 1 (HSV-1) representing the most prevalent virus. In most cases, HSV-1 causes non-life-threatening skin damage in adults. However, in patients with compromised immune systems, it can cause serious diseases, including death. The situation is further complicated by the emergence of strains that are resistant to both traditional and novel antiviral drugs. It is, therefore, imperative that new methods of combating HSV-1 and other herpesviruses be developed without delay. CRISPR/Cas systems may prove an effective means of controlling herpesvirus infections. This review presents the current understanding of the underlying molecular mechanisms of HSV-1 infection and discusses four potential applications of CRISPR/Cas systems in the fight against HSV-1 infections. These include the search for viral and cellular genes that may serve as effective targets, the optimization of anti-HSV-1 activity of CRISPR/Cas systems in vivo, the development of CRISPR/Cas-based HSV-1 diagnostics, and the validation of HSV-1 drug resistance mutations.

Olfactory and trigeminal routes of HSV-1 CNS infection with regional microglial heterogeneity.

Herpes simplex virus type 1 (HSV-1) primarily targets the oral and nasal epithelia before establishing latency in the trigeminal ganglion (TG) and other peripheral ganglia. HSV-1 can also infect and become latent in the central nervous system (CNS) independent of latency in the TGs. Recent studies suggest entry to the CNS via two distinct routes: the TG-brainstem connection and olfactory nerve; however, to date, there is no characterization of brain regions targeted during HSV-1 primary infection. Furthermore, the immune response by microglia may also contribute to the heterogeneity between different brain regions. However, the response to HSV-1 by microglia has not been characterized in a region-specific manner. This study investigated the time course of HSV-1 spread within the olfactory epithelium (OE) and CNS following intranasal inoculation and the corresponding macrophage/microglial response in a C57BL/6 mouse model. We found an apical to basal spread of HSV-1 within the OE and underlying tissue accompanied by an inflammatory response of macrophages. OE infection was followed by infection of a small subset of brain regions targeted by the TG in the brainstem and other cranial nerve nuclei, including the vagus and hypoglossal nerve. Furthermore, other brain regions were positive for HSV-1 antigens, such as the locus coeruleus (LC), raphe nucleus (RaN), and hypothalamus while sparing the hippocampus and cortex. Within each brain region, microglia activation also varied widely. These findings provide critical insights into the region-specific dissemination of HSV-1 within the CNS, elucidating potential mechanisms linking viral infection to neurological and neurodegenerative diseases.IMPORTANCEThis study shows how herpes simplex virus type 1 (HSV-1) spreads within the brain after infecting the nasal passages. Our data reveal the distinct pattern of HSV-1 through the brain during a non-encephalitic infection. Furthermore, microglial activation was also temporally and spatially specific, with some regions of the brain having sustained microglial activation even in the absence of viral antigens. Previous reports have identified specific brain regions found to be positive for HSV-1 infection; however, to date, there has not been a concise investigation of the anatomical spread of HSV-1 and the brain regions consistently vulnerable to viral entry and spread. Understanding these region-specific differences in infection and immune response is crucial because it links HSV-1 infection to potential triggers for neurological and neurodegenerative diseases.

Lactylation of RNA m6A demethylase ALKBH5 promotes innate immune response to DNA herpesviruses and mpox virus

RNA N6-methyladenosine (m6A) demethylase AlkB homolog 5 (ALKBH5) plays a crucial role in regulating innate immunity. Lysine acylation, a widespread protein modification, influences protein function, but its impact on ALKBH5 during viral infections has not been well characterized. This study investigates the presence and regulatory mechanisms of a previously unidentified lysine acylation in ALKBH5 and its role in mediating m6A modifications to activate antiviral innate immune responses. We demonstrate that ALKBH5 undergoes lactylation, which is essential for an effective innate immune response against DNA herpesviruses, including herpes simplex virus type 1 (HSV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and mpox virus (MPXV). This lactylation attenuates viral replication. Mechanistically, viral infections enhance ALKBH5 lactylation by increasing its interaction with acetyltransferase ESCO2 and decreasing its interaction with deacetyltransferase SIRT6. Lactylated ALKBH5 binds interferon-beta (IFN-β) messenger RNA (mRNA), leading to demethylation of its m6A modifications and promoting IFN-β mRNA biogenesis. Overexpression of ESCO2 or depletion of SIRT6 further enhances ALKBH5 lactylation to strengthen IFN-β mRNA biogenesis. Our results identify a posttranslational modification of ALKBH5 and its role in regulating antiviral innate immune responses through m6A modification. The finding provides an understanding of innate immunity and offers a potential therapeutic target for HSV-1, KSHV, and MPXV infections.

Seroprevalence of herpes simplex virus 2 infection among commercial sex workers in Colombo, Sri Lanka

Background: Herpes Simplex Virus Type 2 (HSV2) causes genital herpes, an incurable, lifelong sexually transmitted infection (STI). This study was conducted to describe the seroprevalence and associated factors of HSV2 infection in a cohort of Female Sex Workers (FSWs). Methods: A descriptive cross-sectional study was conducted on 136 FSWs who attended the central STD Clinic, in Colombo. They were assessed using an interviewer-administered questionnaire followed by serum sampling. Serum samples were tested for HSV2 IgG using an enzyme immunoassay specific for glycoprotein gG2 of HSV2. Results: HSV2 seroprevalence of FSW was 66.9% (91/136) of which only 14.3% (13/91) reported a history of genital infection. Age ≥35 years (OR 3.35, 95%CI 1.54-7.31, p=0.002), education ≥ grade 5 (OR 8.35, 95%CI 13.1- 64.7, p<0.001), lifetime sexual partners ≥ 200 (OR 5.33, 95% CI 2.3-12.36), p<0.001), duration of sex work ≥1 year (OR 4.5, 95% CI 2.09-9.65, p<0.001) and history of STI (OR 4.52, 95% CI 1.9-10.78, p<0.001) were statistically significant risk factors for high HSV2 prevalence. Consistent condom use by commercial partners in the last 3 months was not a significant protective factor in preventing HSV2 infection (OR 0.44, 95% CI 0.15-1.26, p = 0.12) in this cohort. Conclusions: The seroprevalence of HSV2 is high in this population and most of them did not report any genital infection. Multiple risk factors for higher prevalence were observed. Findings support the need for regular surveillance, monitoring of HSV-2 infection in high-risk populations, and expanding awareness of HSV-2 infection in the country.

Herpes Simplex Virus Type 2 Blocks IFN-β Production through the Viral UL24 N-Terminal Domain-Mediated Inhibition of IRF-3 Phosphorylation.

Herpes simplex virus type 2 (HSV-2) is a sexually transmitted virus, the cause of genital herpes, and its infection can increase the risk of HIV-1 infection. After initial infection, HSV-2 can establish lifelong latency within the nervous system, which is likely associated with the virus-mediated immune evasion. In this study, we found that HSV-2 UL24 significantly inhibited the activation of the IFN-β promoter and the production of IFN-β at both mRNA and protein levels. Of importance, the inhibitory effect of HSV-2 on IFN-β production was significantly impaired in the context of HSV-2 infection when UL24 was knocked down. Additional studies revealed that, although the full-length HSV-2 UL24 affected cell cycle and viability to some extent, its N-terminal 1-202AA domain showed no obvious cytotoxicity while its C-terminal 201-281 AA domain had a minimal impact on cell viability. Further studies showed that the N-terminal 1-202 AA domain of HSV-2 UL24 (HSV-2 UL24-N) was the main functional region responsible for the inhibition of IFN-β production mediated by HSV-2 UL24. This domain significantly suppressed the activity of RIG-IN, MAVS, TBK-1, IKK-ε, or the IRF-3/5D-activated IFN-β promoter. Mechanistically, HSV-2 UL24-N suppressed IRF-3 phosphorylation, resulting in the inhibition of IFN-β production. The findings of this study highlight the significance of HSV-2 UL24 in inhibiting IFN-β production, revealing two potential roles of UL24 during HSV-2 infection: facilitating immune evasion and inducing cell cycle arrest.

The alphaherpesvirus gE/gI glycoprotein complex and proteases jointly orchestrate invasion across the host's upper respiratory epithelial barrier.

Herpes simplex virus type 1 (HSV-1) infections are a worldwide issue. More than three billion people are infected with HSV-1 globally. Although most infections with HSV-1 occur subclinically, severe symptoms and complications are numerous and can be life-threatening. Complications include encephalitis and blindness. Recently, HSV-1 infections have been associated with the development of Alzheimer's Disease. To date, no effective vaccines against HSV-1 are on the market. Pseudorabies virus (PRV) and bovine herpesvirus type 1 (BoHV-1) are two alphaherpesviruses of major veterinary importance. Although efforts have been made to eradicate these viruses from livestock animals, clinical problems still occur, resulting in great economic losses for farmers. It is evident that new insights into the pathogenesis of alphaherpesviruses are needed, to develop effective treatments and novel preventive therapies.

Co-infection of human papillomavirus and herpes simplex virus-2 with cervical dysplasia among women in Kaduna State, Nigeria

Background: The epidemiology of human papillomavirus (HPV) and co-infections with herpes simplex virus type 2 (HSV-2) remains poorly characterized in Africa. High risk HPV (hrHPV) infection is the primary cause of 99.7% all cervical cancer especially in the presence of genital ulcer disease (GUD) which is usually caused by HSV-2. Herpes simplex virus-2 might interact directly with hrHPV to increase the risk of cervical cancer. Co-infection of HPV and HSV-2 in asymptomatic women could provide a clue to early diagnosis of cervical cancer and this could aid in the development of new strategies for effective management and improvement of the quality of life of women who are infected. If the synergy between HPV and HSV-2 can be prevented, there may be significant reduction of the incidence of cervical cancer. Methodology: This was a descriptive cross-sectional study of 515 randomly selected apparently healthy women of reproductive age whose cervical samples were screened for HPV and HSV-2 in Kaduna State, Nigeria. The cervical samples were collected by liquid-based cytology (LBC) for detection of cervical epithelial cell abnormalities (CEA) and molecular detection of HPV and HSV-2 using conventional polymerase chain reaction (PCR) assay. Extracted viral DNAs from the samples were amplified by convectional PCR using specific hrHPV (HPV 16,18, 31 and 45) primer sets and a broad spectrum MY09/11 and GP5+/6+ primers for a wider range of HPV genotypes while HSV-2 DNA was detected by florescence-based PCR assay with HSV-2 gG primers and probes. Results: PCR assay revealed that 14.7% (n=76) of the 515 selected women harbored HPV, HSV-2 or both. The prevalence of HPV, hrHPV, HSV-2 and HPV/HSV-2 co-infection among in the study participants are 11.8% (n=61), 9.3% (n=48), 5.6% 4% (n=29) and 2.3% (n=12) respectively. The frequency of HPV detection in HSV-2 infected participants (41.4%, 12/29) was significantly higher (OR=6.295, p<0.0001) than in HSV-2 negative participants (10.1%, 49/437), but only co-infections of HPV-31 (p=0.004) and HPV-18 (p=0.040) with HSV-2 were significantly associated. Cervical cytology reports on the smears revealed prevalence of cervical epithelial abnormalities (CEA) of 16.7% (n=86), with cervical dysplasia prevalence of 6.4% (n=33), consisting of high grade squamous intraepithelial lesion (HGSIL) of 1.6% (n=8), low grade squamous intraepithelial lesion (LGSIL) of 4.1% (n=21) and atypical squamous cells of uncertain significance (ASCUS) of 0.8% (n=4). The frequency of HPV detection in women with cervical dysplasia (93.9%, 31/33) was significantly higher (OR=14.22, p<0.0001) than in women without cervical dysplasia (6.2%, 30/482), and all HPV genotypes were significantly associated (p<0.05) with cervical dysplasia except HPV 16 (p=0.051). Also, the frequency of HPV/HSV-2 co-infection among women with cervical dysplasia (15.2%, 5/33) was significantly higher than among women without cervical dysplasia (1.5%, 7/482) (OR=12.12, p<0.0001). Comparing women with cervical inflammatory and atrophic changes (n=53), women with cervical dysplasia (HGSIL, LGSIL and ASC-US) had significantly higher frequency of HPV infection (χ2=42.829, p=0.000), HSV-2 infection (χ2=25.140, p=0.001) and HPV/HSV-2 co-infections (χ2=66.602, p=0.000). Conclusion: Co-infection rate of hrHPV and HSV-2 among women in Kaduna State is 2.3%. Demographic factors significantly influencing the rate of co-infections included age and marital status. In spite of the screening method using the traditional Pap smear, GUD and cervical cancer continues to be a major public health problem, thus more sensitive and specific methods such as liquid based cytology technique and polymerase chain reaction for early detection of cervical dysplasia and hrHPV or HSV-2 in asymptomatic women should be adopted for routine use

Regulation of voltage-gated sodium channels by TNF-α during herpes simplex virus latency establishment.

During lytic or latent infection of sensory neurons with herpes simplex virus type 1 (HSV-1) there are significant changes in the expression of voltage-gated Na+ channels, which may disrupt the transmission of pain information. HSV-1 infection can also evoke the secretion of various pro-inflammatory cytokines, including TNF-α and IL-6. In this work, we hypothesized that TNF-α regulates the expression of Na+ channels during HSV-1 latency establishment in ND7/23 sensory-like neurons. Latency establishment was mimicked by culturing HSV-1 infected ND7/23 cells in the presence of acyclovir (ACV) for 3 days. Changes in the functional expression of voltage-gated Na+ channels were assessed by whole-cell recordings. Our results demonstrate that infection of ND7/23 cells with the HSV-1 strain McKrae with GFP expression (M-GFP) causes a significant decrease in sodium currents during latency establishment. Exposure of ND7/23 cells to TNF-α during latency establishment reverses the effect of HSV-1, resulting in a significant increase in sodium current density. However, Na+ currents were not restored by 3day-treatment with IL-6. There were no changes in the pharmacological and biophysical properties of sodium currents promoted by TNF-α, including sensitivity to tetrodotoxin and the current-voltage relationship. TNF-α stimulation of ND7/23 cells increases p38 signaling. Inhibition of p38 signaling with SB203580 or SB202190 eliminates the stimulatory effect of TNF-α on sodium currents. These results indicate that TNF-α signaling in sensory neurons during latency establishment upregulates the expression of voltage-gated Na+ channels in order to maintain the transmission of pain information.

Acupuncture improves spatial learning and memory impairment caused by herpes simplex virus type-1 in rats through the p38 MAPK/CREB pathway

BackgroundAcupuncture can improve herpes simplex encephalitis (HSE), but the underlying mechanism is not clear. Therefore, we evaluated the cognitive function and apoptosis in hippocampus caused by herpes simplex virus type-1 (HSV-1) in rats after acupuncture and described the molecular mechanism.MethodsSprague–Dawley rats were induced into HSE models by HSV-1 infection. After 3 days, they received acupuncture at the acupoints of Xuanzhong (GB39), Baihui (GV20), Shenmen (HT7), Shenting (GV24), and Sanyinjiao (SP6), and/or intraperitoneal injection of the p38 MAPK inhibitor SB203580. Morris water maze test was performed on rats. The hippocampus of rats was obtained, and the expression of apoptosis-related genes in the tissues was detected by qRT-PCR. In addition, apoptosis-related proteins and proteins related to the p38 MAPK/CREB pathway in the tissues was detected by western blot.ResultsAfter HSV-1 induction, the rat's escape latency was increased, the time spent on the platform in the target quadrant and the number of platform crossings significantly decreased. In addition, there was an increase in apoptosis in the hippocampus, accompanied by elevated levels of p–p38 and decreased levels of p-CREB. However, these effects could be improved by acupuncture treatment. Interestingly, SB203580 plays a similar role to acupuncture, and acupuncture could further enhance the impacts of SB203580 on cognitive function and apoptosis in hippocampus in HSE rats.ConclusionAcupuncture improves spatial learning and memory impairment caused by HSV-1 in rats. The functional mechanism of acupuncture may be through the p38 MAPK/CREB pathway.

Epidemiological characteristics of three herpesviruses infections in children in Nanjing, China, from 2018 to 2023.

To evaluate the epidemiology characteristics of Herpes simplex virus type 2 (HSV-2), Epstein-Barr virus (EBV) and Cytomegalovirus (CMV) infection in children from January 2018 to December 2023, in Nanjing, China. We conducted a retrospective analysis of 21,210, 49,494 and 32,457 outpatients and inpatients aged 1 day to 17 years who were subjected to the three herpesviruses (HSV-2, EBV, and CMV) nucleic acid testing from January 2018 to December 2023, respectively. Demographic information, laboratory findings, etc. were collected and analyzed. HSV-2, EBV and CMV nucleic acid testing were performed by real-time PCR. The total rate of detection of the three herpesviruses for all specimens was 0.32% (67/21,210), 14.99% (7419/49,494), and 8.88% (2881/32,457), respectively. A declining trend in the incidence of viral infections over the years was observed for the three herpesviruses (all P<0.05). The detection rate for HSV-2, EBV, and CMV was highest among patients aged 1-3 years, 3-7 years, and 28 days to 1 year, respectively (all P<0.05). The presence of HSV-2 and CMV infection did not exhibit a discernible seasonal pattern, whereas EBV typically demonstrated an elevation during the summer and autumn. EBV and CMV were both prevalent among children in China, except for HSV-2. The annual prevalence of the three herpesviruses show decreasing trend from 2018 to 2023, and no difference in gender (except for EBV). EBV infections usually occur in the summer and autumn, whereas HSV-2 and CMV do not exhibit significant seasonality. The positivity rate of HSV-2 is highest in 1-3 years, EBV is highest in 3-7 years, and that of CMV is highest in 28 days to 1 year. Positive detection rates are higher in outpatients than in inpatients.

The antimicrobial protein RNase 7 directly restricts herpes simplex virus infection of human keratinocytes.

Approximately 22% of moderately to severely affected atopic dermatitis (AD) patients have a history of eczema herpeticum, a disseminated rash primarily caused by herpes simplex virus type 1 (HSV-1). Reduced activity of antimicrobial peptides may contribute to the increased susceptibility of AD patients to HSV-1. We previously demonstrated that the antimicrobial protein RNase 7 limits HSV-1 infection of human keratinocytes by promoting self-DNA sensing. Here, we addressed whether RNase 7 has any effect on HSV-1 infection when infecting keratinocytes without exogenously added costimulatory DNA, and which step(s) of the infection cycle RNase 7 interferes with. We quantified viral gene expression by RT-qPCR and flow cytometry, viral genome replication by qPCR, virucidal effects by plaque titration, and plaque formation and the subcellular localization of incoming HSV-1 particles by microscopy. Recombinant RNase 7 restricted HSV-1 gene expression, genome replication, and plaque formation in human keratinocytes. It decreased HSV-1 immediate-early transcripts independently of the induction of interferon-stimulated genes. Its main effect was on intracellular infection processes and not on extracellular virions or virus binding to cells. RNase 7 reduced the amount of cell-associated capsids and the HSV-1 envelope glycoprotein D at 3 but not at 0.5 h postinfection. Our data show that RNase 7 directly restricts HSV-1 infection of human keratinocytes, possibly by promoting the degradation of incoming HSV-1 particles. This suggests that RNase 7 may limit HSV-1 spread in the skin and that mechanisms that reduce its activity in the lesional skin of AD patients may increase their susceptibility to eczema herpeticum.

Development and characterization of formulations based on combinatorial potential of antivirals against genital herpes.

Herpes simplex virus type 2 (HSV-2) treatment faces challenges due to antiviral resistance and systemic side effects of oral therapies. Local delivery of antiviral agents, such as tenofovir (TDF) and zinc acetate dihydrate (ZAD), may offer improved efficacy and reduced systemic toxicity. This study's objective is to develop and evaluate local unit dose formulations of TDF and ZAD combination for local treatment of HSV-2 infection and exploring their individual and combinatory effects in vitro. The study involved the development of immediate-release film and pessary formulations containing TDF and ZAD. These formulations were characterized for physicochemical properties and in vitro drug release profiles. Cytotoxicity and antiviral activity assays were conducted to evaluate the individual and combinatory effects of TDF and ZAD. Film formulations released over 90% of the drugs within 1h, and pessary formulations within 90min, ensuring effective local drug delivery. ZAD showed moderate antiviral activity while TDF exhibited significant antiviral activity at non-cytotoxic concentrations. The combination of TDF and ZAD demonstrated synergistic effects in co-infection treatments, reducing the concentration required for 50% inhibition of HSV-2. Developed film and pessary formulations offer consistent and predictable local drug delivery, enhancing antiviral efficacy while minimizing systemic side effects. The combination of TDF and ZAD showed potential synergy against HSV-2, particularly in co-infection treatments. Further preclinical studies on pharmacokinetics, safety, and efficacy are necessary to advance these formulations toward clinical application.

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

BackgroundTo 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.MethodsAn in vitro model of HSV-1 infection was established by infecting BV2 cells with HSV-1.ResultsCompared 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-β), 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.ConclusionsIn 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.

A novel GFP-based strategy to quantitate cellular spatial associations in HSV-1 viral pathogenesis.

Periodic reactivation of herpes simplex virus type 1 (HSV-1) triggers immune responses that result in corneal scarring (CS), known as herpes stromal keratitis (HSK). Despite considerable research, fully understanding HSK and eliminating it remains challenging due to a lack of comprehensive analysis of HSV-1-infected immune cells in both corneas and trigeminal ganglia (TG). We engineered a recombinant HSV-1 expressing green fluorescent protein (GFP) in the virulent McKrae virus strain that does not require corneal scarification for efficient virus replication (GFP-McKrae). Next-generation sequencing (NGS) analysis, along with in vitro and in vivo assays, showed that GFP-McKrae virus was similar to WT-McKrae virus. Furthermore, corneal cells infected with GFP-McKrae were quantitatively analyzed using image mass cytometry (IMC). The single-cell reconstruction data generated cellular maps of corneas based on the expression of 25 immune cell markers in GFP-McKrae-infected mice. Corneas from mock control mice showed the presence of T cells and macrophages, whereas corneas from GFP-McKrae-infected mice on days 3 and 5 post-infection (PI) exhibited increased immune cells. Notably, on day 3 PI, increased GFP expression was observed in closely situated clusters of DCs, macrophages, and epithelial cells. By day 5 PI, macrophages and T cells became prominent. Finally, immunostaining methods detected HSV-1 or GFP and gD proteins in latently infected TG. This study presents a valuable strategy for identifying cellular spatial associations in viral pathogenesis and holds promise for future therapeutic applications.IMPORTANCEThe goal of this study was to establish quantitative approaches to analyze immune cell markers in HSV-1-infected intact corneas and trigeminal ganglia from primary and latently infected mice. This allowed us to define spatial and temporal interactions between specific immune cells and their potential roles in virus replication and latency. To accomplish this important goal, we took advantage of the utility of GFP-McKrae virus as a valuable research tool while also highlighting its potential to uncover previously unrecognized cell types that play pivotal roles in HSV-1 replication and latency. Such insights will pave the way for developing targeted therapeutic approaches to tackle HSV-1 infections more effectively.

Prevalence of sexually transmitted infections (STIs) among first time visitors at STIs clinic in Hangzhou, China: Assessing the influence of the COVID-19 pandemic.

This study assesses the prevalence of sexually transmitted infections (STIs) in first time visitors to the STIs clinic in Hangzhou, China, considering different genders, ages and symptoms. And also explores howthe COVID-19 pandemic has affected on STIs. From 2019 to 2023, 27,283 first time visitors were tested for nine distinct STIs, including Human Papillomavirus (HPV), Human Immunodeficiency Virus (HIV), syphilis, Herpes Simplex Virus type 2 (HSV-2), Ureaplasma urealyticum (UU), Chlamydia trachomatis (CT), Neisseria gonorrhoeae (NG), Mycoplasma genitalium (MG), and vaginal Candida. Symptomatic male and female visitors showed overall STI-positive rates of 39.27% and 59.20%, respectively(p < .001). The top three pathogens in both genders were HPV (47.56% and 56.71%), UU (29.21% and 56.47%), and HSV-2 (22.41% and 52.94%). Among asymptomatic visitors, the total STI-positive rate was 36.63% in males and 52.03% in females. Age-stratified analysis revealed higher STI rates in visitors ≤ 20 or >50 years, regardless of gender and symptoms. During the COVID-19 pandemic, symptomatic visitors showed lower positive rates for HPV, HIV, syphilis, and HSV-2, while Candida, UU, CT, NG, and multiple infections increased. Among asymptomatic visitors, HPV had the lowest positive rate, while NG and multiple infections increased during the pandemic. STI prevalence is notably high, particularly in those aged ≤ 20 and >50 years. It emphasizes the need for enhanced health education, condom use, and vaccination. The COVID-19 pandemic impacting STIs through varied factors, such as reduced sexual activity and clinical service interruption.

HSV-2 Manipulates Autophagy through Interferon Pathway: A Strategy for Viral Survival.

Autophagy, an evolutionarily conserved cellular process, influences the regulation of viral infections. While the existing understanding indicates that Herpes Simplex Virus type 2 (HSV-2) maintains a basal level of autophagy to support its viral yield, the precise pathways governing the induction of autophagy during HSV-2 infection remain unknown. Therefore, this study aims to explore the role of type I interferons (IFN-I) in modulating autophagy during HSV-2 infection and to decode the associated signaling pathways. Our findings revealed an interplay wherein IFN-I regulates the autophagic response during HSV-2 infection. Additionally, we investigated the cellular pathways modulated during this complex process. Exploring the intricate network of signaling events involved in autophagy induction during HSV-2 infection holds promising therapeutic implications. Identifying these pathways advances our understanding of host-virus interactions and holds the foundation for developing targeted therapeutic strategies against HSV-2. The insight gained from this study provides a platform for exploring potential therapeutic targets to restrict HSV-2 infections, addressing a crucial need in antiviral research.

HSV-1 infection induces phosphorylated tau propagation among neurons via extracellular vesicles.

Extracellular vesicles (EV), key players in cell-to-cell communication, may contribute to disease propagation in several neurodegenerative diseases, including Alzheimer's disease (AD), by favoring the dissemination of neurotoxic proteins within the brain. Interestingly, growing evidence supports the role of herpes simplex virus type 1 (HSV-1) infection in the pathogenesis of AD. Here, we investigated whether HSV-1 infection could promote the spread of phosphorylated tau (ptau) among neurons via EV. We analyzed the ptau species that were secreted via EV following HSV-1 infection in neuroblastoma cells and primary neurons, focusing particularly on T205, T181, and T217, the phosphorylation sites mainly associated with AD. Moreover, by overexpressing human tau tagged with GFP (htauGFP), we found that recipient tau knockout (KO) neurons uptook EV that are loaded with HSV-1-induced phtauGFP. Finally, we exploited an in vivo model of acute infection and assessed that cerebral HSV-1 infection promotes the release of ptau via EV in the brain of infected mice. Overall, our data suggest that, following HSV-1 infection, EV play a role in tau spreading within the brain, thus contributing to neurodegeneration.IMPORTANCEHerpes simplex virus type 1 (HSV-1) infection that reaches the brain has been repeatedly linked with the appearance of the pathognomonic markers of Alzheimer's disease (AD), including accumulation of amyloid beta and hyperphosphorylated tau proteins, and cognitive deficits. AD is a multifactorial neurodegenerative disease representing the most common form of dementia in the elderly, and no cure is currently available, thus prompting additional investigation on potential risk factors and pathological mechanisms. Here, we demonstrate that the virus exploits the extracellular vesicles (EV) to disseminate phosphorylated tau (ptau) among brain cells. Importantly, we provide evidence that the HSV-1-induced EV-bearing ptau can be undertaken by recipient neurons, thus likely contributing to misfolding and aggregation of native tau, as reported for other AD models. Hence, our data highlight a novel mechanism exploited by HSV-1 to propagate tau-related damage in the brain.

Fas/FasL-Mediated Apoptosis and Inflammation Contribute to Recovery from HSV-2-Mediated Spinal Cord Infection.

Herpes simplex virus type 2 (HSV-2) is a sexually transmitted pathogen that causes a persistent infection in sensory ganglia. The infection manifests itself as genital herpes but in rare cases it can cause meningitis. In this study, we used a murine model of HSV-2 meningitis to show that Fas and FasL are induced within the CNS upon HSV-2 infection, both on resident microglia and astrocytes and on infiltrating monocytes and lymphocytes. Mice lacking Fas or FasL had a more severe disease development with significantly higher morbidity, mortality, and an overall higher CNS viral load. In parallel, these Fas/FasL-deficient mice showed a severely impaired infection-induced CNS inflammatory response with lower levels of infiltrating CD4+ T-cells, lower levels of Th1 cytokines and chemokines, and a shift in the balance between M1 and M2 microglia/monocytes. In vitro, we confirmed that Fas and FasL is required for the induction of leucocyte apoptosis, but also show that the Fas/FasL pathway is required for adequate cytokine and chemokine production by glial cells. In summary, our data show that the Fas/FasL cell death receptor pathway is an important defense mechanism in the spinal cord as it down-regulates HSV-2-induced inflammation while at the same time promoting adequate anti-viral immune responses against infection.