Herpes Simplex Virus Type 1 Infection of Human Periodontal Ligament.

The periodontal ligament (PDL) is a complex connective tissue that connects the tooth root to the dental alveolar bone and plays crucial mechanical roles. PDL also exhibits regenerative roles and regulatory functions to maintain periodontium integrity and homeostasis. While PDL exposure to oral microbial pathogens is common, virtually nothing is known regarding viral infections of PDL. In particular, human herpes simplex virus type 1 (HSV-1) persistently infects the oral cavity through infections of the oral epithelium, connective tissue and neurons. While the oral spread of HSV-1 is generally asymptomatic, this virus has also been implicated in various oral pathologies. In this study, using a primary cell model derived from PDL (PDL cells), and whole surgical fragments of PDL, we provide evidence supporting the efficient infection of PDL by HSV-1 and the promotion of cytopathic effects. Infection of PDL by HSV-1 was also associated with an acute innate inflammatory response, as illustrated by the production of antiviral interferons and pro-inflammatory cytokines. Furthermore, this inflammatory response to HSV-1 was exacerbated in the presence of bacterial-derived products, such as peptidoglycans. This work therefore highlights the ability of HSV-1 to infect mesenchymal cells from PDL, suggesting that PDL may serve as a viral reservoir for the periodontal spread of HSV-1. Moreover, this raises questions about HSV-1 oral pathogenesis, as HSV-1-associated cytopathic and inflammatory effects may contribute to profound alterations of PDL integrity and functioning.

Asymptomatic herpes simplex virus brain infection elicits cellular senescence phenotypes in the central nervous system of mice suffering multiple sclerosis-like disease.

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease affecting the central nervous system (CNS) in animals that parallels several clinical and molecular traits of multiple sclerosis in humans. Herpes simplex virus type 1 (HSV-1) infection mainly causes cold sores and eye diseases, yet eventually, it can also reach the CNS, leading to acute encephalitis. Notably, a significant proportion of healthy individuals are likely to have asymptomatic HSV-1 brain infection with chronic brain inflammation due to persistent latent infection in neurons. Because cellular senescence is suggested as a potential factor contributing to the development of various neurodegenerative disorders, including multiple sclerosis, and viral infections may induce a premature senescence state in the CNS, potentially increasing susceptibility to such disorders, here we examine the presence of senescence-related markers in the brains and spinal cords of mice with asymptomatic HSV-1 brain infection, EAE, and both conditions. Across all scenarios, we find a significant increases of senescence biomarkers in the CNS with some differences depending on the analyzed group. Notably, some senescence biomarkers are exclusively observed in mice with the combined conditions. These results indicate that asymptomatic HSV-1 brain infection and EAE associate with a significant expression of senescence biomarkers in the CNS.

Small Animal Models to Study Herpes Simplex Virus Infections.

Herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) are two of the most prevalent human viruses worldwide. They are known to cause a variety of diseases including genital herpes, meningitis, encephalitis, cold sores and herpes stromal keratitis. The seropositive rate for HSV-1 is around 90%, whereas for HSV-2 it remains around 20-25% for the general adult population. The infections caused by these viruses remain difficult to study because a large proportion of infected individuals are asymptomatic. Furthermore, given the neurotropic characteristics of the virus, studies aimed at understanding the complex pathogenesis in humans is difficult. As a result, animal models have been developed to understand several characteristics of HSV biology, pathogenesis, disease and host responses to infection. These models are also commonly used as the first evaluation of new drugs and vaccines. There are several well-established animal models to study infection with HSV, including mice, guinea pigs and rabbits. Variables within the animal models depend on the species of animal, route of infection, viral strain, dosage, etc. This review aims at summarizing the most commonly used animal models to study HSV pathogenesis and therapies.

Human TMEFF1 is a restriction factor for herpes simplex virus in the brain.

Most cases of herpes simplex virus 1 (HSV-1) encephalitis (HSE) remain unexplained1,2. Here, we report on two unrelated people who had HSE as children and are homozygous for rare deleterious variants of TMEFF1, which encodes a cell membrane protein that is preferentially expressed by brain cortical neurons. TMEFF1 interacts with the cell-surface HSV-1 receptor NECTIN-1, impairing HSV-1 glycoprotein D- and NECTIN-1-mediated fusion of the virus and the cell membrane, blocking viral entry. Genetic TMEFF1 deficiency allows HSV-1 to rapidly enter cortical neurons that are either patient specific or derived from CRISPR-Cas9-engineered human pluripotent stem cells, thereby enhancing HSV-1 translocation to the nucleus and subsequent replication. This cellular phenotype can be rescued by pretreatment with type I interferon (IFN) or the expression of exogenous wild-type TMEFF1. Moreover, ectopic expression of full-length TMEFF1 or its amino-terminal extracellular domain, but not its carboxy-terminal intracellular domain, impairs HSV-1 entry into NECTIN-1-expressing cells other than neurons, increasing their resistance to HSV-1 infection. Human TMEFF1 is therefore a host restriction factor for HSV-1 entry into cortical neurons. Its constitutively high abundance in cortical neurons protects these cells from HSV-1 infection, whereas inherited TMEFF1 deficiency renders them susceptible to this virus and can therefore underlie HSE.

Emergence of novel hypervirulent Acinetobacter baumannii strain and herpes simplex type 1 virus in a case of community-acquired pneumonia in China.

BACKGROUND: A. baumannii is an important and common clinical pathogen, especially in the intensive care unit (ICU). This study aimed to characterize one hypervirulent A. baumannii strain in a patient with community-acquired pneumonia and herpes simplex type 1 virus infection. METHODS: Minimum inhibitory concentrations (MICs) were determined using the Kirby-Bauer (K-B) and broth microdilution methods. Galleria mellonella infection model experiment was conducted. Whole-genome sequencing (WGS) was performed using the Illumina and Nanopore platforms. The resistance and virulence determinants were identified using the ABRicate program with ResFinder and the VFDB database. The capsular polysaccharide locus (K locus) and lipooligosaccharide outer core locus (OC locus) were identified using Kleborate with Kaptive. Phylogenetic analyses were conducted using the BacWGSTdb server. RESULTS: A. baumannii XH2146 strain belongs to ST10Pas and ST447Oxf. The strain was resistant to cefazolin, ciprofloxacin, and trimethoprim/sulfamethoxazole (TMP-SMX). Bautype and Kaptive analyses showed that XH2146 contains OCL2 and KL49. WGS analysis revealed that the strain harbored blaADC-76, blaOXA-68, ant(3'')-IIa, tet(B), and sul2. Notably, tet(B) and sul2, both were located within a 114,700-bp plasmid (designated pXH2146-1). Virulence assay revealed A. baumannii XH2146 possessed higher virulence than A. baumannii AB5075 at 12 h. Comparative genomic analysis showed that A. baumannii ST447 strains were mainly isolated from the USA and exhibited a relatively close genetic relationship. Importantly, 11 strains were observed to carry blaOXA-58; blaOXA-23 was identified in 11 isolates and three ST447 A. baumannii strains harbored blaNDM-1. CONCLUSIONS: Early detection of community-acquired hypervirulent Acinetobacter baumannii strains is recommended to prevent their extensive spread in hospitals.

Identification of a novel neurovirulence factor encoded by the cryptic orphan gene UL31.6 of herpes simplex virus 1.

Although the herpes simplex virus type 1 (HSV-1) genome was thought to contain approximately 80 different protein coding sequences (CDSs), recent multi-omics analyses reported HSV-1 encodes more than 200 potential CDSs. However, few of the newly identified CDSs were confirmed to be expressed at the peptide or protein level in HSV-1-infected cells. Furthermore, the impact of the proteins they encode on HSV-1 infection is largely unknown. This study focused on a newly identified CDS, UL31.6. Re-analyzation of our previous chemical proteomics data verified that UL31.6 was expressed at the peptide level in HSV-1-infected cells. Antisera raised against a viral protein encoded by UL31.6 (pUL31.6) reacted with a protein with an approximate molecular mass of 37 kDa in lysates of Vero cells infected with each of three HSV-1 strains. pUL31.6 was efficiently dissociated from virions in high-salt solution. A UL31.6-null mutation had a minimal effect on HSV-1 gene expression, replication, cell-to-cell spread, and morphogenesis in Vero cells; in contrast, it significantly reduced HSV-1 cell-to-cell spread in three neural cells but not in four non-neural cells including Vero cells. The UL31.6-null mutation also significantly reduced the mortality and viral replication in the brains of mice after intracranial infection, but had minimal effects on pathogenic manifestations in and around the eyes, and viral replication detected in the tear films of mice after ocular infection. These results indicated that pUL31.6 was a tegument protein and specifically acted as a neurovirulence factor by potentially promoting viral transmission between neuronal cells in the central nervous system.IMPORTANCERecent multi-omics analyses reported the herpes simplex virus type 1 (HSV-1) genome encodes an additional number of potential coding sequences (CDSs). However, the expressions of these CDSs at the peptide or protein levels and the biological effects of these CDSs on HSV-1 infection remain largely unknown. This study annotated a cryptic orphan CDS, termed UL31.6, an HSV-1 gene that encodes a tegument protein with an approximate molecular mass of 37 kDa, which specifically acts as a neurovirulence factor. Our study indicates that HSV-1 proteins important for viral pathogenesis remain to be identified and a comprehensive understanding of the pathogenesis of HSV-1 will require not only the identification of cryptic orphan CDSs using emerging technologies but also step-by-step and in-depth analyses of each of the cryptic orphan CDSs.

Microbial infection promotes amyloid pathology in a mouse model of Alzheimer's disease via modulating γ-secretase.

Microbial infection as a type of environmental risk factors is considered to be associated with long-term increased risk of dementia, including Alzheimer's disease (AD). AD is characterized by two neuropathologically molecular hallmarks of hyperphosphorylated tau and amyloid-ß (Aß), the latter generated by several biochemically reactive enzymes, including γ-secretase. However, how infectious risk factors contribute to pathological development of the AD core molecules remains to be addressed. In this work, we utilized a modified herpes simplex virus type 1 (mHSV-1) and found that its hippocampal infection locally promotes Aß pathology in 5 × FAD mice, the commonly used amyloid model. Mechanistically, we identified HSV-1 membrane glycoprotein US7 (Envelope gI) that interacts with and modulates γ-secretase and consequently facilitates Aß production. Furthermore, we presented evidence that adenovirus-associated virus-mediated locally hippocampal overexpression of the US7 aggravates Aß pathology in 5 × FAD mice. Collectively, these findings identify a herpesviral factor regulating γ-secretase in the development and progression of AD and represent a causal molecular link between infectious pathogens and neurodegeneration.

Mice with type I interferon signaling deficiency are prone to epilepsy upon HSV-1 infection.

Viral encephalitis continues to be a significant public health concern. In our previous study, we discovered a lower expression of antiviral factors, such as IFN-ß, STING and IFI16, in the brain tissues of patients with Rasmussen's encephalitis (RE), a rare chronic neurological disorder often occurred in children, characterized by unihemispheric brain atrophy. Furthermore, a higher cumulative viral score of human herpes viruses (HHVs) was also found to have a significant positive correlation with the unihemispheric atrophy in RE. Type I IFNs (IFN-I) signaling is essential for innate anti-infection response by binding to IFN-α/ß receptor (IFNAR). In this study, we infected WT mice and IFNAR-deficient A6 mice with herpes simplex virus 1 (HSV-1) via periocular injection to investigate the relationship between IFN-I signaling and HHVs-induced brain lesions. While all mice exhibited typical viral encephalitis lesions in their brains, HSV-induced epilepsy was only observed in A6 mice. The gene expression matrix, functional enrichment analysis and protein-protein interaction network revealed four gene models that were positively related with HSV-induced epilepsy. Additionally, ten key genes with the highest scores were identified. Taken together, these findings indicate that intact IFN-I signaling can effectively limit HHVs induced neural symptoms and brain lesions, thereby confirming the positive correlation between IFN-I signaling repression and brain atrophy in RE and other HHVs encephalitis.

Erupción variceliforme de Kaposi y enfermedad de Darier / Kaposi's varicelliform rash and Darier's disease

La erupción variceliforme de Kaposi es una infección cutánea diseminada, causada en la mayor parte de los casos por el virus Herpes simple tipo 1. Se suele presentar en pacientes con alteraciones preexistentes de la barrera cutánea, especialmente en niños con dermatitis atópica. Se comunica el caso de un paciente de 84 años, quien negaba enfermedades cutáneas previas, que consultó por lesiones dolorosas y pruriginosas, en la piel del tórax y el abdomen, de 3 semanas de evolución. Con sospecha de una enfermedad infecciosa viral, bacteriana, ampollar o neutrofílica, se realizó inmunofluorescencia directa para herpes, cultivo y biopsia de piel para estudio histológico. La inmunofluorescencia fue positiva para Herpes simple tipo 1 y el estudio histopatológico mostró cambios compatibles con infección herpética y enfermedad de Darier. La enfermedad de Darier es una genodermatosis infrecuente que se suele manifestar en la adolescencia. Si bien su diagnóstico en la ancianidad es excepcional, este caso ilustra que se debe considerar en todos los pacientes que presenten erupción variceliforme. (AU)

Kaposi's varicelliform rash is a disseminated cutaneous infection, caused by Herpes virus 1. It usually presents in patients with pre-existing skin barrier disorders, especially in children with atopic dermatitis. We report the case of an 84-year-old patient, who reported having no previous skin diseases, who consulted for painful, itchy, 3-week-old skin lesions. As we suspected viral, bacterial, bullous or neutrophilic disease, direct immunofluorescence, culture, and skin biopsy for histological study were performed. Immunofluorescence was positive for Herpes simplex type 1 and the histopathological study showed changes compatible with herpetic infection and Darier's disease. Darier's disease is a rare genodermatosis that usually manifests in adolescence. Although its diagnosis in old age is anecdotal, it should be considered in patients with a varicelliform rash. (AU)

Herpes simplex virus tipo 1 como factor de riesgo asociado con la enfermedad de Alzheimer / Herpes simplex virus type 1 as risk factor associated to Alzheimer disease

Herpes simplex virus type 1 (HSV-1) is ubiquitous, neurotropic, and the most common pathogenic cause of sporadic acute encephalitis in humans. Herpes simplex encephalitis is associated with a high mortality rate and significant neu-rological, neuropsychological, and neurobehavioral sequels. HSV-1 infects limbic system structures in the central nervous system (CNS), and has been suggested as an environmental risk factor for Alzheimer’s disease. The possibility that HSV-1 reactivates in CNS neurons causing chronic progressive damage at cellular level and altering the neuronal functionality has not been thoroughly investigated. Currently it is ignored if recurrent reactivation of HSV-1 in asymptomatic patients involves some risk of progressive deterioration of the CNS functions caused, in example, by a neuroinflammatory response against the virus or by direct toxicity of the pathogen on neurons. Therefore, studies regarding the routes of dissemination of HSV-1 from the peripheral ganglions to the CNS, as well as the possible cellular and molecular mechanisms implied in generating neuronal damage during latent and productive infection, are of much relevance.

Prevalência do herpes-vírus humano tipo 1 em neoplasias cutâneas epiteliais malignas / Prevalence of human herpes virus type 1 in epithelial skin cancer

FUNDAMENTOS - O DNA viral pode atuar como oncogene, favorecendo o desenvolvimento de neoplasias, como as linfoides e da pele. Entre esses vírus, encontram-se alguns herpes-vírus humanos. OBJETIVO - Identificar a presença de DNA do herpes-vírus humano tipo 1 em neoplasias epiteliais pré-malignas,malignas e pele normal de indivíduos controle, avaliando seu papel na carcinogênese. MÉTODOS - Identificação, por reação em cadeia da polimerase, do DNA viral do tumor e pele sã de 41 pacientes e comparação com grupo controle, sem neoplasia. Análise estatística: Testes de Fisher e de McNemar. RESULTADOS - O vírus foi identificado em 20 indivíduos sem e em 21 com neoplasia. Destes últimos, 11 o expessaram apenas nas células tumorais. A diferença, entretanto, não foi estatisticamente significante. CONCLUSÕES - Parece não haver relação direta entre o encontro do DNA viral na pele sã e na pele tumoral. Sua presença pode facilitar o desenvolvimento da neoplasia ou apenas coincidir de se localizar onde esta já ocorreu.

BACKGROUND - Viral DNA may act as an oncogene, especially in skin and lymphoid organs. This group includes some human herpes virus. OBJECTIVE - To identify human herpes virus type 1 DNA in pre-malignant and malignant skin samples of epithelial tumors comparing to normal skin to determine its role in carcinogenesis. METHODS - Forty-one patients with epithelial tumors were submitted to biopsies from tumor and normal skin. The control group comprised 41 biopsies from patients with other dermatoses than cancer. After DNA extraction, polymerase chain reaction was performed to identify 199-bp band. The results were statistically evaluated by Fisher and McNemar tests. RESULTS - The virus was identified in 20 subjects without cancer and in 21 with skin cancer. From these, 11 expressed it only in tumor cells. This difference was not significant. CONCLUSION - There seem to be no direct relation between viral findings in normal skin and skin cancer cells. It may act as a promoter or just coexist at the same site where a neoplastic transformation has already occurred.

Esofagite herpética / Herpetic esophagitis

Relata-se caso de um paciente de 19 anos, portador de Linfoma Não-Hodgkin em tratamento quimioterápico que desenvolveu Esofagite Herpética. São discutidas as diversas manifestações clínicas e endocópicas, revisando-se a literatura

Imágenes por resonancia magnética en la encefalitis por virus herpes simple 1 / MR features in herpes simplex encephalitis type I

Introducción: La encefalitis por herpes simple (EHS) en niños y adultos, es producida por el virus herpes simple serotipo 1 (VHS 1), y constituye la causa más común de encefalitis fatales no epidémicas. El tratamiento precoz con antivirales disminuye significativamente la morbimortalidad. El diagnóstico de EHS puede establecerse por análisis de líquido cefalorraquídeo (LCR), aunque las técnicas habitualmente utilizadas pueden arrojar resultados normales dentro de la primera semana del comienzo de los síntomas. Actualmente el diagnóstico temprano se establece con los datos clínicos y electroencefalográficos, apoyados en los hallazgos de imágenes por Resonancia Magnética (RM). Casos presentados: Se presentan 5 casos de EHS estudiados por tomografía computada (TC) y RM. Se analizan los hallazgos en imágenes por RM en estadio agudo, subagudo y crónico, y se discuten brevemente los mecanismos patogénicos y las características clínicas y EEG de la enfermedad. Conclusión: Las imágenes por RM muestran cambios patológicos tempranos con elevada sensibilidad, por lo que ante la sospecha clínica de EHS constituyen el método de diagnóstico por imágenes de elección