HVEM is a TNF Receptor with Multiple Regulatory Roles in the Mucosal Immune System

Inflammatory bowel disease and rheumatoid arthritis share a common genetic structure

Background

The comorbidity rate of inflammatory bowel disease (IBD) and rheumatoid arthritis (RA) is high; nevertheless, the reasons behind this high rate remain unclear. Their similar genetic makeup probably contributes to this comorbidity.

Methods

Based on data obtained from the genome-wide association study of IBD and RA, we first assessed an overall genetic association by performing the linkage disequilibrium score regression (LDSC) analysis. Further, a local correlation analysis was performed by estimating the heritability in summary statistics. Next, the causality between the two diseases was analyzed by two-sample Mendelian randomization (MR). A genetic overlap was analyzed by the conditional/conjoint false discovery rate (cond/conjFDR) method.LDSC with specific expression of gene analysis was performed to identify related tissues between the two diseases. Finally, GWAS multi-trait analysis (MTAG) was also carried out.

Results

IBD and RA are correlated at the genomic level, both overall and locally. The MR results suggested that IBD induced RA. We identified 20 shared loci between IBD and RA on the basis of a conjFDR of <0.01. Additionally, we identified two tissues, namely spleen and small intestine terminal ileum, which were commonly associated with both IBD and RA.

Conclusion

Herein, we proved the presence of a polygenic overlap between the genetic makeup of IBD and RA and provided new insights into the genetic architecture and mechanisms underlying the high comorbidity between these two diseases.

Genetically predicted N-methylhydroxyproline levels mediate the association between naive CD8+ T cells and allergic rhinitis: a mediation Mendelian randomization study

Background

Allergic rhinitis (AR), a prevalent chronic inflammatory condition triggered by immunoglobulin E (IgE), involves pivotal roles of immune and metabolic factors in its onset and progression. However, the intricacies and uncertainties in clinical research render current investigations into their interplay somewhat inadequate.

Objective

To elucidate the causal relationships between immune cells, metabolites, and AR, we conducted a mediation Mendelian randomization (MR) analysis.

Methods

Leveraging comprehensive publicly accessible summary-level data from genome-wide association studies (GWAS), this study employed the two-sample MR research method to investigate causal relationships among 731 immune cell phenotypes, 1400 metabolite levels, and AR. Additionally, employing the mediation MR approach, the study analyzed potential mediated effect of metabolites in the relationships between immune cells and AR. Various sensitivity analysis methods were systematically employed to ensure the robustness of the results.

Results

Following false discovery rate (FDR) correction, we identified three immune cell phenotypes as protective factors for AR: Naive CD8br %CD8br (odds ratio (OR): 0.978, 95% CI = 0.966-0.990, P = 4.5×10-4), CD3 on CD39+ activated Treg (OR: 0.947, 95% CI = 0.923-0.972, P = 3×10-5), HVEM on CD45RA- CD4+ (OR: 0.967, 95% CI = 0.948-0.986, P = 4×10-5). Additionally, three metabolite levels were identified as risk factors for AR: N-methylhydroxyproline levels (OR: 1.219, 95% CI = 1.104-1.346, P = 9×10-5), N-acetylneuraminate levels (OR: 1.133, 95% CI = 1.061-1.211, P = 1.7×10-4), 1-stearoyl-2-arachidonoyl-gpc (18:0/20:4) levels (OR: 1.058, 95% CI = 1.029-1.087, P = 5×10-5). Mediation MR analysis indicated a causal relationship between Naive CD8br %CD8br and N-methylhydroxyproline levels, acting as a protective factor (OR: 0.971, 95% CI = 0.950-0.992, P = 8.31×10-3). The mediated effect was -0.00574, accounting for 26.1% of the total effect, with a direct effect of -0.01626. Naive CD8+ T cells exert a protective effect on AR by reducing N-methylhydroxyproline levels.

Conclusion

Our study, delving into genetic information, has substantiated the intricate connection between immune cell phenotypes and metabolite levels with AR. This reveals a potential pathway to prevent the onset of AR, providing guiding directions for future clinical investigations.

Herpesvirus Entry Mediator as an Immune Checkpoint Target and a Potential Prognostic Biomarker in Myeloid and Lymphoid Leukemia

Herpesvirus entry mediator (HVEM) is a molecular switch that can modulate immune responses against cancer. The significance of HVEM as an immune checkpoint target and a potential prognostic biomarker in malignancies is still controversial. This study aims to determine whether HVEM is an immune checkpoint target with inhibitory effects on anti-tumor CD4+ T cell responses in vitro and whether HVEM gene expression is dysregulated in patients with acute lymphocytic leukemia (ALL). HVEM gene expression in tumor cell lines and peripheral blood mononuclear cells (PBMCs) from ALL patients and healthy controls was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Tumor cells were left untreated (control) or were treated with an HVEM blocker before co-culturing with CD4+ T cells in vitro in a carboxyfluorescein succinimidyl ester (CFSE)-dependent proliferation assay. HVEM expression was upregulated in the chronic myelogenous leukemia cell line (K562) (FC = 376.3, p = 0.086) compared with normal embryonic kidney cells (Hek293). CD4+ T cell proliferation was significantly increased in the HVEM blocker-treated K562 cells (p = 0.0033). Significant HVEM differences were detected in ALL PBMCs compared with the controls, and these were associated with newly diagnosed ALL (p = 0.0011) and relapsed/refractory (p = 0.0051) B cell ALL (p = 0.0039) patients. A significant differentiation between malignant ALL and the controls was observed in a receiver operating characteristic (ROC) curve analysis with AUC = 0.78 ± 0.092 (p = 0.014). These results indicate that HVEM is an inhibitory molecule that may serve as a target for immunotherapy and a potential ALL biomarker.

Transcriptomic and proteomic study of cancer cell lines exposed to actinomycin D and nutlin-3a reveals numerous, novel candidates for p53-regulated genes

Transcriptomic analyses have revealed hundreds of p53-regulated genes; however, these studies used a limited number of cell lines and p53-activating agents. Therefore, we searched for candidate p53-target genes by employing stress factors and cell lines never before used in a high-throughput search for p53-regulated genes. We performed RNA-Seq on A549 cells exposed to camptothecin, actinomycin D, nutlin-3a, as well as a combination of actinomycin D and nutlin-3a (A + N). The latter two substances synergise upon the activation of selected p53-target genes. A similar analysis was performed on other cell lines (U-2 OS, NCI-H460, A375) exposed to A + N. To identify proteins in cell lysates or those secreted into a medium of A549 cells in control conditions or treated with A + N, we employed mass spectrometry. The expression of selected genes strongly upregulated by A + N or camptothecin was examined by RT-PCR in p53-deficient cells and their controls. We found that p53 participates in the upregulation of: ACP5, APOL3, CDH3, CIBAR2, CRABP2, CTHRC1, CTSH, FAM13C, FBXO2, FRMD8, FRZB, GAST, ICOSLG, KANK3, KCNK6, KLRG2, MAFB, MR1, NDRG4, PTAFR, RETSAT, TMEM52, TNFRSF14, TRANK1, TYSND1, WFDC2, WFDC5, WNT4 genes. Twelve of these proteins were detected in the secretome and/or proteome of treated cells. Our data generated new hypotheses concerning the functioning of p53. Many genes activated by A + N or camptothecin are also activated by interferons, indicating a noticeable overlap between transcriptional programs of p53 and these antiviral cytokines. Moreover, several identified genes code for antagonists of WNT/β-catenin signalling pathways, which suggests new connections between these two cancer-related signalling systems. One of these antagonists is DRAXIN. Previously, we found that its gene is activated by p53. In this study, using mass spectrometry and Western blotting, we detected expression of DRAXIN in a medium of A549 cells exposed to A + N. Thus, this protein functions not only in the development of the nervous system, but it may also have a new cancer-related function.

Responsiveness to Vedolizumab Therapy in Ulcerative Colitis is Associated With Alterations in Immune Cell-Cell Communications

BACKGROUND

Ulcerative colitis (UC) and Crohn's disease are 2 types of inflammatory bowel disease (IBD), a group of chronic digestive disorders caused by aberrant immune responses to intestinal microbes. Although changes in the composition of immune cell subsets in the context of IBD have been previously described, the interactions and communication among cells are less well understood. Moreover, the precise mechanisms of action underlying many biologic therapies, including the anti-α4β7 integrin antagonist vedolizumab, remain incompletely understood. Our study aimed to explore possible additional mechanisms through which vedolizumab acts.

METHODS

We performed cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) on peripheral blood and colon immune cells derived from patients with ulcerative colitis treated with the anti-α4β7 integrin antagonist vedolizumab. We applied a previously published computational approach, NicheNet, to predict immune cell-cell interactions, revealing putative ligand-receptor pairs and key transcriptional changes downstream of these cell-cell communications (CCC).

RESULTS

We observed decreased proportions of T helper 17 (TH17) cells in UC patients who responded to vedolizumab and therefore focused the study on identifying cell-cell communications and signals of TH17 cells with other immune cells. For example, we observed that colon TH17 cells from vedolizumab nonresponders were predicted to have a greater degree of interactions with classical monocytes compared with responders, whereas colon TH17 cells from vedolizumab responders exhibited more interactions with myeloid dendritic cells compared with nonresponders.

CONCLUSIONS

Overall, our results indicate that efforts to elucidate cell-cell communications among immune and nonimmune cell types may increase the mechanistic understanding of current and investigational therapies for IBD.

Lymphocyte HVEM/BTLA co-expression after critical illness demonstrates severity indiscriminate upregulation, impacting critical illness-induced immunosuppression

Introduction

The co-regulatory molecule, HVEM, can stimulate or inhibit immune function, but when co-expressed with BTLA, forms an inert complex preventing signaling. Altered HVEM or BTLA expression, separately have been associated with increased nosocomial infections in critical illness. Given that severe injury induces immunosuppression, we hypothesized that varying severity of shock and sepsis in murine models and critically ill patients would induce variable increases in HVEM/BTLA leukocyte co-expression.

Methods

In this study, varying severities of murine models of critical illness were utilized to explore HVEM⁺BTLA⁺ co-expression in the thymic and splenic immune compartments, while circulating blood lymphocytes from critically ill patients were also assessed for HVEM⁺BTLA⁺ co-expression.

Results

Higher severity murine models resulted in minimal change in HVEM⁺BTLA⁺ co-expression, while the lower severity model demonstrated increased HVEM⁺BTLA⁺ co-expression on thymic and splenic CD4⁺ lymphocytes and splenic B220⁺ lymphocytes at the 48-hour time point. Patients demonstrated increased co-expression of HVEM⁺BTLA⁺ on CD3⁺ lymphocytes compared to controls, as well as CD3⁺Ki67^- lymphocytes. Both L-CLP 48hr mice and critically ill patients demonstrated significant increases in TNF-α.

Discussion

While HVEM increased on leukocytes after critical illness in mice and patients, changes in co-expression did not relate to degree of injury severity of murine model. Rather, co-expression increases were seen at later time points in lower severity models, suggesting this mechanism evolves temporally. Increased co-expression on CD3⁺ lymphocytes in patients on non-proliferating cells, and associated TNF-α level increases, suggest post-critical illness co-expression does associate with developing immune suppression.

Single-cell eQTL analysis of activated T cell subsets reveals activation and cell type-dependent effects of disease-risk variants

The impact of genetic variants on cells challenged in biologically relevant contexts has not been fully explored. Here, we activated CD4⁺ T cells from 89 healthy donors and performed a single-cell RNA sequencing assay with >1 million cells to examine cell type-specific and activation-dependent effects of genetic variants. Single-cell expression quantitative trait loci (sc-eQTL) analysis of 19 distinct CD4⁺ T cell subsets showed that the expression of over 4000 genes is significantly associated with common genetic polymorphisms and that most of these genes show their most prominent effects in specific cell types. These genes included many that encode for molecules important for activation, differentiation, and effector functions of T cells. We also found new gene associations for disease-risk variants identified from genome-wide association studies and highlighted the cell types in which their effects are most prominent. We found that biological sex has a major influence on activation-dependent gene expression in CD4⁺ T cell subsets. Sex-biased transcripts were significantly enriched in several pathways that are essential for the initiation and execution of effector functions by CD4⁺ T cells like TCR signaling, cytokines, cytokine receptors, costimulatory, apoptosis, and cell-cell adhesion pathways. Overall, this DICE (Database of Immune Cell Expression, eQTLs, and Epigenomics) subproject highlights the power of sc-eQTL studies for simultaneously exploring the activation and cell type-dependent effects of common genetic variants on gene expression (https://dice-database.org).

The Implementation of TNFRSF Co-Stimulatory Domains in CAR-T Cells for Optimal Functional Activity

The Tumor Necrosis Factor Receptor Superfamily (TNFRSF) is a large and important immunoregulatory family that provides crucial co-stimulatory signals to many if not all immune effector cells. Each co-stimulatory TNFRSF member has a distinct expression profile and a unique functional impact on various types of cells and at different stages of the immune response. Correspondingly, exploiting TNFRSF-mediated signaling for cancer immunotherapy has been a major field of interest, with various therapeutic TNFRSF-exploiting anti-cancer approaches such as 4-1BB and CD27 agonistic antibodies being evaluated (pre)clinically. A further application of TNFRSF signaling is the incorporation of the intracellular co-stimulatory domain of a TNFRSF into so-called Chimeric Antigen Receptor (CAR) constructs for CAR-T cell therapy, the most prominent example of which is the 4-1BB co-stimulatory domain included in the clinically approved product Kymriah. In fact, CAR-T cell function can be clearly influenced by the unique co-stimulatory features of members of the TNFRSF. Here, we review a select group of TNFRSF members (4-1BB, OX40, CD27, CD40, HVEM, and GITR) that have gained prominence as co-stimulatory domains in CAR-T cell therapy and illustrate the unique features that each confers to CAR-T cells.

Investigation of IL-4, IL-10, and HVEM polymorphisms with esophageal squamous cell carcinoma: a case-control study involving 1929 participants

It is believed that an individual’s hereditary factors may be involved in the development of esophageal cancer (EC). The present study recruited 721 esophageal squamous cell carcinoma (ESCC) cases and 1208 controls and explored the roles of single nucleotide polymorphisms (SNPs) in the interleukin-4 (IL-4), IL-10, and herpesvirus entry mediator (HVEM) genes in contributing to ESCC risk. IL-4, IL-10, and HVEM SNPs were analyzed by employing an SNPscan method. After adjustment for body mass index (BMI), smoking, drinking, age and gender, we identified that the rs2070874 T>C locus in IL-4 gene decreased the risk of ESCC (CC vs. TT: P=0.008; CC vs. TT/TC: P=0.010). After a stratified analysis, we suggested that the IL-4 rs2070874 T>C variants might be a protective factor for ESCC in male, ≥63 years old, never smoking, drinking and BMI < 24 kg/m² subgroups. In addition, we identified that the rs2243263 G>C polymorphism in IL-4 gene was a risk factor for ESCC development in the BMI ≥ 24 kg/m² subgroup (GC vs. GG: P=0.030 and GC/CC vs. GG: P=0.018). We identified an association of the IL-4 rs2070874 T>C SNP with the decreased susceptibility of ESCC in stage I/II subgroup. Finally, we found an association of the IL-10 rs1800872 T>G SNP with a worse differentiation (TG vs. TT: P=0.048 and GG/TG vs. TT: P=0.032). In conclusion, the findings indicate a potential importance of IL-4 rs2070874 T>C, IL-4 rs2243263 G>C and IL-10 rs1800872 T>G SNPs in the development of ESCC.

Single-cell analyses of Crohn's disease tissues reveal intestinal intraepithelial T cells heterogeneity and altered subset distributions

Crohn's disease (CD) is a chronic transmural inflammation of intestinal segments caused by dysregulated interaction between microbiome and gut immune system. Here, we profile, via multiple single-cell technologies, T cells purified from the intestinal epithelium and lamina propria (LP) from terminal ileum resections of adult severe CD cases. We find that intraepithelial lymphocytes (IEL) contain several unique T cell subsets, including NKp30⁺γδT cells expressing RORγt and producing IL-26 upon NKp30 engagement. Further analyses comparing tissues from non-inflamed and inflamed regions of patients with CD versus healthy controls show increased activated T_H17 but decreased CD8⁺T, γδT, T_FH and Treg cells in inflamed tissues. Similar analyses of LP find increased CD8⁺, as well as reduced CD4⁺T cells with an elevated T_H17 over Treg/T_FH ratio. Our analyses of CD tissues thus suggest a potential link, pending additional validations, between transmural inflammation, reduced IEL γδT cells and altered spatial distribution of IEL and LP T cell subsets.

Unmasking Unique Immune Altering Aspects of the Microbiome as a Tool to Correct Sepsis-Induced Immune Dysfunction

Background: Sepsis-related mortality is driven by immune dysfunction. A bidirectional micro-organism-immune cell cross talks exists. Gut Bacteroides fragilis-T-cell crosstalk maintains innate immune cell/pathogen homeostasis. Commensal gut Clostridia spp. suppress inflammation and induce gut tolerance. Probiotics are administered to restore immune microbiome homeostasis. Individual microbial components have an immunomodulatory effect. However, probiotic therapies for sepsis-induced immune disruptions are rarely tailored to specific immune responses. Thus, we ask the question as to how components of the intestinal microbiome, often found in probiotic therapies, affect lymphocyte phenotypic profile? Methods: T-lymphocytes were cultured with either monomicrobial or polymicrobial combinations. Microbes used were Bacteroides fragilis, Clostridium perfringens, or Lactobacillus acidophilus. Cytokines, measured by enzyme-linked immunosorbent assay (ELISA)-included interleukin (IL)-6, IL-10, IL-22, and IL-33. Flow cytometry was used for T-cell phenotyping for program-death receptor-1 (PD-1) and B- and T-lymphocyte attenuator (BTLA). T-cell DNA was extracted to assess global epigenetic changes. For translation, IL-33 was measured from surgical intensive care unit (ICU) patients with sepsis with either monomicrobial or polymicrobial infection. Results: Lactobacillus consistently induced IL-22 and IL-33. Bacteroides fragilis induced IL-33 only under polymicrobial (pB) conditions. Within surgical ICU patients, IL-33 levels were higher in polymicrobial versus monomicrobial patients. PD-1⁺ expression was lowest with either monomicrobial Bacteroides fragilis or Bacteroides fragilis predominant polymicrobial context. Conversely Bacteroides fragilis exposure induced a distinct PD-1^-high subpopulation. B- and T-lymphocyte attenuator-positive expression did not differ after individual microbes. Among polymicrobial conditions, Bacteroides fragilis predominant (pB) and Lactobacillus acidophilus predominant (pL) increased BTLA⁺ expression. DNA methylation was most increased in response to Clostridium perfringens in monomicrobial and in response to Bacteroides fragilis in polymicrobial conditions. Conclusion: Unique microbe/lymphocyte interactions occur. Bacteroides fragilis induced a T-cell phenotype consistent with potential long-term immune recovery. This work begins to discover how varying microbes may induce unique functional and phenotypic T-lymphocyte responses.

In Vitro Zika Virus Infection of Human Neural Progenitor Cells: Meta-Analysis of RNA-Seq Assays

The Zika virus (ZIKV) is an emergent arthropod-borne virus (arbovirus) responsible for congenital Zika syndrome (CZS) and a range of other congenital malformations. Evidence shows that ZIKV infects human neural progenitor cells (hNPCs) in the fetal brain, prompting inflammation and tissue damage/loss. Despite recent advances, little is known about the pathways involved in CZS pathogenesis. We performed a meta-analysis, gene ontology (GO), and pathway analysis of whole transcriptome studies with the aim of clarifying the genes and pathways potentially altered during hNPCs infection with ZIKV. We selected three studies (17 samples of infected hPNCs compared to hPNCs uninfected controls) through a systematic search of the Gene Expression Omnibus (GEO) database. The raw reads were trimmed, counted, and normalized. Next, we performed a rank product meta-analysis to detect consistently differentially expressed genes (DEGs) in these independent experiments. We detected 13 statistically significant DEGs. GO ontology and reactome analysis showed an enrichment of interferon, pro-inflammatory, and chemokines signaling and apoptosis pathways in ZIKV-infected cells. Moreover, we detected three possible new candidate genes involved in hNPCs infection: APOL6, XAF1, and TNFRSF1. Our results confirm that interferon (IFN) signaling dominates the ZIKV response, and that a crucial contribution is given by apoptotic pathways, which might elicit the CZS phenotype.

Herpes Virus Entry Mediator (HVEM): A Novel Potential Mediator of Trauma-Induced Immunosuppression

BACKGROUND

Herpes virus entry mediator (HVEM) is a coinhibitory molecule which can both stimulate and inhibit host immune responses. Altered expression of HVEM and its ligands is associated with increased nosocomial infections in septic patients. We hypothesize critically ill trauma patients will display increased lymphocyte HVEM expression and that such alteration is predictive of infectious events.

MATERIALS AND METHODS

Trauma patients prospectively enrolled from the ICU were compared with healthy controls. Leukocytes were isolated from whole blood, stained for CD3 (lymphocytes) and HVEM, and evaluated by flow cytometry. Charts were reviewed for injuries sustained, APACHE II score, hospital course, and secondary infections.

RESULTS

Trauma patients (n = 31) were older (46.7 ± 2.4 versus 36.8 ± 2.1 y; P = 0.03) than healthy controls (n = 10), but matched for male sex (74% versus 60%; P = 0.4). Trauma patients had higher presenting WBC (13.9 ± 1.3 versus 5.6 ± 0.5 × 106/mL; P = 0.002), lower percentage of CD3+ lymphocytes (7.5% ± 0.8 versus 22.5% ± 0.9; P < 0.001), but significantly greater expression of HVEM+/CD3+ lymphocytes (89.6% ± 1.46 versus 67.3% ± 1.7; P < 0.001). Among trauma patients, secondary infection during the hospitalization was associated with higher APACHE II scores (20.6 ± 1.6 versus 13.6 ± 1.4; P = 0.03) and markedly lower CD3+ lymphocyte HVEM expression (75% ± 2.6 versus 93% ± 0.7; P < 0.01).

CONCLUSIONS

HVEM expression on CD3+ cells increases after trauma. Patients developing secondary infections have less circulating HVEM+CD3+. This implies HVEM signaling in lymphocytes plays a role in maintaining host defense to infection in after trauma. HVEM expression may represent a marker of infectious risk as well as a potential therapeutic target, modulating immune responses to trauma.

High expression of herpes virus entry mediator is associated with poor prognosis in clear cell renal cell carcinoma

Herpes virus entry mediator (HVEM), also called tumor necrosis factor receptor superfamily 14 (TNFRSF14), is highly expressed in various tumor tissues and plays critical roles in tumor biology. However, the role of HVEM in clear cell renal cell carcinoma (ccRCC) is unknown. This study evaluated the clinical importance of HVEM in patients with ccRCC. HVEM expression was assessed in fresh and 140 archived paraffin-embedded ccRCC tissue samples by quantitative RT-PCR, western blot, and immunohistochemical staining. HVEM expression was higher in ccRCC than in paired peritumor tissue. Kaplan-Meier analysis showed that high level of HVEM expression was associated with poor overall survival (OS) and disease-free survival (DFS) in patients with ccRCC (both P < 0.001). Multivariate analysis indicated that HVEM overexpression was independently prognostic of survival in ccRCC patients. Two novel nomogram systems were constructed by integrating HVEM expression and other clinical parameters to predict OS (c-index 0.75) and DFS (c-index 0.74) in these patients, with both having better predictive accuracy than traditional TNM (c-index 0.65 for OS and 0.639 for DFS) and Fuhrman (c-index 0.612 for OS and 0.641 for DFS) systems. In addition, HVEM silencing led to an observable reduction in tumor cells growth in vitro and in vivo. Taken together, these findings indicate that high HVEM expression is a novel and independent adverse predictor of clinical outcomes in patients with ccRCC and that HVEM may be a potential therapeutic target.

Immune checkpoint molecule herpes virus entry mediator is overexpressed and associated with poor prognosis in human glioblastoma

Background

Dysregulation of immune checkpoint molecules leads to immune evasion in human tumours but has become a viable target for tumour therapy. Here, we examined expression of Herpes virus entry mediator (HVEM), an immune checkpoint molecule, in human glioblastoma (GBM) to assess its potential as a molecular target for treatment.

Methods

Molecular and clinical data from publicly available genomic databases containing WHO grade II-IV human glioma cases (n = 1866) were analyzed. Immunohistochemistry was applied to assess HVEM protein levels in primary tumour sections. Statistical analysis was performed using Matlab and R language.

Findings

HVEM was found to be elevated in aggressive gliomas, particularly in the mesenchymal and isocitrate dehydrogenase (IDH) wild-type molecular subtypes of GBM. HVEM^high tumours tended to be associated with amplification of EGFR and loss of PTEN, while HVEM^low tumours harbored mutations in IDH1 (93%). HVEM exhibited potential as a prognostic marker based on Cox regression and nomogram models. HVEM displayed intra-tumour heterogeneity and was more highly expressed in peri-necrotic and microvascular regions. Gene ontology and pathway analysis revealed enrichment of HVEM in multiple immune regulatory processes, such as suppression of T cell mediated immunity in GBM. Finally, in cell lineage analysis, HVEM was found to be tightly associated with several infiltrating immune and stromal cell types which localized to the tumour microenvironment.

Interpretation

Our data highlights the importance of HVEM in the development of GBM and as a potential molecular target in combination with current immune checkpoint blockades for treatment of GBM.

Characterization of Sex Differences in Ocular Herpes Simplex Virus 1 Infection and Herpes Stromal Keratitis Pathogenesis of Wild-Type and Herpesvirus Entry Mediator Knockout Mice

Sex differences related to immune response and inflammation play a role in the susceptibility and pathogenesis of a variety of viral infections and disease (S. L. Klein, Bioessays 34:1050-1059, 2012, https://doi.org/10.1002/bies.201200099). Herpes simplex virus 1 (HSV-1) causes chronic inflammatory disease in the cornea, an immune-privileged tissue, resulting in irreversible damage and blindness in affected individuals (A. Rowe, A. St Leger, S. Jeon, D. K. Dhaliwal, et al., Prog Retin Eye Res 32:88-101, 2013, https://doi.org/10.1016/j.preteyeres.2012.08.002). Our research focuses on the role of herpesvirus entry mediator (HVEM) as an immune regulator during ocular HSV-1 infection. Mice lacking HVEM (HVEM knockout [KO] mice) exhibit lower levels of immune cell infiltrates and less severe ocular disease in the cornea than wild-type (WT) mice. As sex differences contribute to pathogenesis in many inflammatory diseases, we tested whether sex acts as a biological variable in the immune response to HSV-1 infection and herpes stromal keratitis (HSK) pathogenesis. Adult male and female WT and HVEM KO mice were inoculated with HSV-1 via corneal scarification and monitored daily for disease course. Viral titers were determined, and immune cell infiltrates were collected and analyzed. Our results indicated no significant differences in viral titers in tear film or affected tissues, in immune cell infiltration, or in clinical symptoms between males and females of either genotype. These results suggest that sex is not a significant biological variable in this experimental model and that male and female mice of the C57BL/6 background can be used similarly in studies of ocular HSV-1 pathogenesis.IMPORTANCE Sex hormones have come to be considered an important factor for the development of certain diseases only recently and as such should continue to be considered a biological variable. Ocular HSV-1, and the resulting HSK, is the leading cause of infectious blindness worldwide. We compared levels of ocular HSV-1 infection and pathogenesis in the two sexes and found no significance differences between male and female WT mice or HVEM KO mice.

Aberrant Expressions of Co-stimulatory and Co-inhibitory Molecules in Autoimmune Diseases

Co-signaling molecules include co-stimulatory and co-inhibitory molecules and play important roles in modulating immune responses. The roles of co-signaling molecules in autoimmune diseases have not been clearly defined. We assessed the expressions of co-stimulatory and co-inhibitory molecules in autoimmune diseases through a bioinformatics-based study. By using datasets of whole-genome transcriptome, the expressions of 54 co-stimulatory or co-inhibitory genes in common autoimmune diseases were analyzed using Robust rank aggregation (RRA) method. Nineteen array datasets and 6 RNA-seq datasets were included in the RRA discovery study and RRA validation study, respectively. Significant genes were further validated in several autoimmune diseases including Graves' disease (GD). RRA discovery study suggested that CD160 was the most significant gene aberrantly expressed in autoimmune diseases (Adjusted P = 5.9E-12), followed by CD58 (Adjusted P = 5.7E-06) and CD244 (Adjusted P = 9.5E-05). RRA validation study also identified CD160 as the most significant gene aberrantly expressed in autoimmune diseases (Adjusted P = 5.9E-09). We further found that the aberrant expression of CD160 was statistically significant in multiple autoimmune diseases including GD (P < 0.05), and CD160 had a moderate role in diagnosing those autoimmune diseases. Flow cytometry confirmed that CD160 was differentially expressed on the surface of CD8⁺ T cells between GD patients and healthy controls (P = 0.002), which proved the aberrant expression of CD160 in GD at the protein level. This study suggests that CD160 is the most significant co-signaling gene aberrantly expressed in autoimmune diseases. Treatment strategy targeting CD160-related pathway may be promising for the therapy of autoimmune diseases.

Herpesvirus Entry Mediator and Ocular Herpesvirus Infection: More than Meets the Eye

As its name suggests, the host receptor herpesvirus entry mediator (HVEM) facilitates herpes simplex virus (HSV) entry through interactions with a viral envelope glycoprotein. HVEM also bridges several signaling networks, binding ligands from both tumor necrosis factor (TNF) and immunoglobulin (Ig) superfamilies with diverse, and often opposing, outcomes. While HVEM was first identified as a viral entry receptor for HSV, it is only recently that HVEM has emerged as an important host factor in immunopathogenesis of ocular HSV type 1 (HSV-1) infection. Surprisingly, HVEM exacerbates disease development in the eye independently of entry. HVEM signaling has been shown to play a variety of roles in modulating immune responses to HSV and other pathogens, and there is increasing evidence that these effects are responsible for HVEM-mediated pathogenesis in the eye. Here, we review the dual branches of HVEM function during HSV infection: entry and immunomodulation. HVEM is broadly expressed; intersects two important immunologic signaling networks; and impacts autoimmunity, infection, and inflammation. We hope that by understanding the complex range of effects mediated by this receptor, we can offer insights applicable to a wide variety of disease states.

Identification of the long, edited dsRNAome of LPS-stimulated immune cells

Endogenous double-stranded RNA (dsRNA) must be intricately regulated in mammals to prevent aberrant activation of host inflammatory pathways by cytosolic dsRNA binding proteins. Here, we define the long, endogenous dsRNA repertoire in mammalian macrophages and monocytes during the inflammatory response to bacterial lipopolysaccharide. Hyperediting by adenosine deaminases that act on RNA (ADAR) enzymes was quantified over time using RNA-seq data from activated mouse macrophages to identify 342 Editing Enriched Regions (EERs), indicative of highly structured dsRNA. Analysis of publicly available data sets for samples of human peripheral blood monocytes resulted in discovery of 3438 EERs in the human transcriptome. Human EERs had predicted secondary structures that were significantly more stable than those of mouse EERs and were located primarily in introns, whereas nearly all mouse EERs were in 3' UTRs. Seventy-four mouse EER-associated genes contained an EER in the orthologous human gene, although nucleotide sequence and position were only rarely conserved. Among these conserved EER-associated genes were several TNF alpha-signaling genes, including Sppl2a and Tnfrsf1b, important for processing and recognition of TNF alpha, respectively. Using publicly available data and experimental validation, we found that a significant proportion of EERs accumulated in the nucleus, a strategy that may prevent aberrant activation of proinflammatory cascades in the cytoplasm. The observation of many ADAR-edited dsRNAs in mammalian immune cells, a subset of which are in orthologous genes of mouse and human, suggests a conserved role for these structured regions.

Herpesvirus entry mediator on radiation-resistant cell lineages promotes ocular herpes simplex virus 1 pathogenesis in an entry-independent manner

Ocular herpes simplex virus 1 (HSV-1) infection leads to a potentially blinding immunoinflammatory syndrome, herpes stromal keratitis (HSK). Herpesvirus entry mediator (HVEM), a widely expressed tumor necrosis factor (TNF) receptor superfamily member with diverse roles in immune signaling, facilitates viral entry through interactions with viral glycoprotein D (gD) and is important for HSV-1 pathogenesis. We subjected mice to corneal infection with an HSV-1 mutant in which HVEM-mediated entry was specifically abolished and found that the HVEM-entry mutant produced clinical disease comparable to that produced by the control virus. HVEM-mediated induction of corneal cytokines, which correlated with an HVEM-dependent increase in levels of corneal immune cell infiltrates, was also gD independent. Given the complexity of HVEM immune signaling, we used hematopoietic chimeric mice to determine which HVEM-expressing cells mediate HSV-1 pathogenesis in the eye. Regardless of whether the donor was a wild-type (WT) or HVEM knockout (KO) strain, HVEM KO recipients were protected from ocular HSV-1, suggesting that HVEM on radiation-resistant cell types, likely resident cells of the cornea, confers wild-type-like susceptibility to disease. Together, these data indicate that HVEM contributes to ocular pathogenesis independently of entry and point to an immunomodulatory role for this protein specifically on radiation-resistant cells.

Immune privilege is maintained in the eye in order to protect specialized ocular tissues, such as the translucent cornea, from vision-reducing damage. Ocular herpes simplex virus 1 (HSV-1) infection can disrupt this immune privilege, provoking a host response that ultimately brings about the majority of the damage seen with the immunoinflammatory syndrome herpes stromal keratitis (HSK). Our previous work has shown that HVEM, a host TNF receptor superfamily member that also serves as a viral entry receptor, is a critical component contributing to ocular HSV-1 pathogenesis, although its precise role in this process remains unclear. We hypothesized that HVEM promotes an inflammatory microenvironment in the eye through immunomodulatory actions, enhancing disease after ocular inoculation of HSV-1. Investigating the mechanisms responsible for orchestrating this aberrant immune response shed light on the initiation and maintenance of HSK, one of the leading causes of infectious blindness in the developed world.

Cutting Edge: the BTLA-HVEM regulatory pathway interferes with protective immunity to intestinal Helminth infection

Helminths exploit intrinsic regulatory pathways of the mammalian immune system to dampen the immune response directed against them. In this article, we show that infection with the parasitic nematode Strongyloides ratti induced upregulation of the coinhibitory receptor B and T lymphocyte attenuator (BTLA) predominantly on CD4(+) T cells but also on a small fraction of innate leukocytes. Deficiency of either BTLA or its ligand herpes virus entry mediator (HVEM) resulted in reduced numbers of parasitic adults in the small intestine and reduced larval output throughout infection. Reduced parasite burden in BTLA- and HVEM-deficient mice was accompanied by accelerated degranulation of mucosal mast cells and increased Ag-specific production of the mast cell-activating cytokine IL-9. Our combined results support a model whereby BTLA on CD4(+) T cells and additional innate leukocytes is triggered by HVEM and delivers negative signals into BTLA(+) cells, thereby interfering with the protective immune response to this intestinal parasite.