Elevated Serum Levels of Herpes Virus Entry Mediator and IL-5 in Cough Variant Asthma Versus Classic Asthma Patients

BackgroundCough variant asthma (CVA) is a special phenotype of asthma. The precise inflammatory features of patients with CVA, however, is still unclear. We aimed to elucidate the differential inflammatory features in patients with CVA in contrast to patients with classic asthma (CA). MethodsA total of 68 patients with persistent uncontrolled asthma (34 with CVA, 34 with CA) in Shenzhen People’s Hospital between August 2018 and May 2019 were enrolled. We collected the demographic data, pulmonary function test (PFT) parameters, hematological variables, and several serum biomarkers. Receiver operating characteristic (ROC) curves were generated to evaluate the values of biomarkers for distinguishing between CVA and CA. ResultsCompared with CA group, CVA group had a higher percentage of females (73.5 vs. 50%, P = 0.046), lower proportion of asthma family history (5.9 vs. 29.4%, P = 0.011), shorter disease course [12.0 (4.8, 39) vs. 96.0 (48.0, 240.0) months, P < 0.001], and better pulmonary function (P all < 0.05). Increased levels of blood eosinophil count [0.35 (0.13, 0.94) vs. 0.34 (0.01, 0.53) X109/L, P = 0.045], eosinophil percentage [6.3 (3.0, 9.8) vs. 4.4 (0.2, 8.4) %, P = 0.046], serum IL-5 [104.19 (89.03, 199.66) vs. 84.57 (26.87, 103.58) ng/L, P = 0.011], and serum herpesvirus entry mediator (HVEM) [128.53 (100.89, 204.83) vs. 90.71 (37.05, 108.08) pg/mL, P = 0.002] were also found in CVA patients compared to those in CA patients. The logistic analysis revealed that serum HVEM had a strong predictive power for CVA group (OR = 1.105, P = 0.015). The sensitivities and specificity of serum HVEM and IL-5 to distinguish between CVA and CA at optimal cut-offs were 85.0% and 61.1%; 85.0% and 61.1%, respectively. AUCs of serum HVEM and IL-5 were 0.789 and 0.739, respectively. Furthermore, serum HVEM and IL-5 had no correlation with PFT parameters in CVA group (P all > 0.05).ConclusionsElevated serum levels of HVEM and IL-5 are exhibited in CVA patients, which may indicate their important roles in the pathogenesis and progression of CVA.

EFFECT OF FREE FATTY ACID ON EXPRESION OF LIGHT AND HVEM mRNA LEVELS IN CULTURED SKELETAL MUSCLE CELLS

Light, tumor necrosis factor superfamily member 14 (TNFSF14), is a secreted peptide of the TNF superfamily. It binds to the herpesvirus entry mediator (HVEM). Light\HVEM signaling is well reported as an important factor linking inflammation and obesity. Here, in the current study, we manipulated skeletal muscle cells incubated in media containing free fatty acid (FFA) to mimic an obesity-related inflammatory environment. Our result revealed that FFA strongly induced expression of mRNA levels of light and interleukin 6 (IL6) - an inflammatory cytokine in the skeletal muscle cells. Surprisingly, expression of HVEM mRNA levels was not significantly different between the FFA-treated skeletal muscle cells and the control cells. These data suggest that FFA increases light expression in skeletal muscle cells that in turn, can bind to HVEM as an autocrine effect inducing inflammatory responses in skeletal muscle cells.

Herpesvirus Entry Mediator Binding Partners Mediate Immunopathogenesis of Ocular Herpes Simplex Virus 1 Infection

ABSTRACT Ocular herpes simplex virus 1 (HSV-1) infection leads to an immunopathogenic disease called herpes stromal keratitis (HSK), in which CD4+ T cell-driven inflammation contributes to irreversible damage to the cornea. Herpesvirus entry mediator (HVEM) is an immune modulator that activates stimulatory and inhibitory cosignals by interacting with its binding partners, LIGHT (TNFSF14), BTLA (B and T lymphocyte attenuator), and CD160. We have previously shown that HVEM exacerbates HSK pathogenesis, but the involvement of its binding partners and its connection to the pathogenic T cell response have not been elucidated. In this study, we investigated the role of HVEM and its binding partners in mediating the T cell response using a murine model of ocular HSV-1 infection. By infecting mice lacking the binding partners, we demonstrated that multiple HVEM binding partners were required for HSK pathogenesis. Surprisingly, while LIGHT−/−, BTLA−/−, and CD160−/− mice did not show differences in disease compared to wild-type mice, BTLA−/− LIGHT−/− and CD160−/− LIGHT−/− double knockout mice showed attenuated disease characterized by decreased clinical symptoms, increased retention of corneal sensitivity, and decreased infiltrating leukocytes in the cornea. We determined that the attenuation of disease in HVEM−/−, BTLA−/− LIGHT−/−, and CD160−/− LIGHT−/− mice correlated with a decrease in gamma interferon (IFN-γ)-producing CD4+ T cells. Together, these results suggest that HVEM cosignaling through multiple binding partners induces a pathogenic Th1 response to promote HSK. This report provides new insight into the mechanism of HVEM in HSK pathogenesis and highlights the complexity of HVEM signaling in modulating the immune response following ocular HSV-1 infection. IMPORTANCE Herpes simplex virus 1 (HSV-1), a ubiquitous human pathogen, is capable of causing a progressive inflammatory ocular disease called herpes stromal keratitis (HSK). HSV-1 ocular infection leads to persistent inflammation in the cornea resulting in outcomes ranging from significant visual impairment to complete blindness. Our previous work showed that herpesvirus entry mediator (HVEM) promotes the symptoms of HSK independently of viral entry and that HVEM expression on CD45+ cells correlates with increased infiltration of leukocytes into the cornea during the chronic inflammatory phase of the disease. Here, we elucidated the role of HVEM in the pathogenic Th1 response following ocular HSV-1 infection and the contribution of HVEM binding partners in HSK pathogenesis. Investigating the molecular mechanisms of HVEM in promoting corneal inflammation following HSV-1 infection improves our understanding of potential therapeutic targets for HSK.

Invasion of Herpes Simplex Virus 1 into Murine Dermis: Role of Nectin-1 and Herpesvirus Entry Mediator as Cellular Receptors during Aging

ABSTRACT Skin is a major target tissue of herpes simplex virus 1 (HSV-1), and we are only beginning to understand how individual receptors contribute to the initiation of infection in tissue. We recently demonstrated the impact of the receptors nectin-1 and herpesvirus entry mediator (HVEM) for entry of HSV-1 into murine epidermis. Here, we focus on viral invasion into the dermis, a further critical target tissue in vivo. In principle, murine dermal fibroblasts are highly susceptible to HSV-1, and we previously showed that nectin-1 and HVEM can act as alternative receptors. To characterize their contribution as receptors in dermal tissue, we established an ex vivo infection assay of murine dermis. Only after separation of the epidermis from the dermis, we observed single infected cells in the upper dermis from juvenile mice at 5 h postinfection with increasing numbers of infected cells at later times. While nectin-1-expressing cells were less frequently detected, we found HVEM expressed on most cells of juvenile dermis. The comparison of infection efficiency during aging revealed a strong delay in the onset of infection in the dermis from aged mice. This observation correlated with a decrease in nectin-1-expressing fibroblasts during aging while the number of HVEM-expressing cells remained stable. Accordingly, aged nectin-1-deficient dermis was less susceptible to HSV-1 than the dermis from control mice. Thus, we conclude that the reduced availability of nectin-1 in aged dermis is a key contributor to a decrease in infection efficiency during aging. IMPORTANCE HSV-1 is a prevalent human pathogen which invades skin and mucocutaneous linings. So far, the underlying mechanisms of how the virus invades tissue, reaches its receptors, and initiates infection are still unresolved. To unravel the mechanical prerequisites that limit or favor viral invasion into tissue, we need to understand the contribution of the receptors that are involved in viral internalization. Here, we investigated the invasion process into murine dermis with the focus on receptor availability and found that infection efficiency decreases in aging mice. Based on studies of the expression of the receptors nectin-1 and HVEM, we suggest that the decreasing number of nectin-1-expressing fibroblasts leads to a delayed onset of infection in the dermis from aged compared to juvenile mice. Our results imply that the level of infection efficiency in murine dermis is closely linked to the availability of the receptor nectin-1 and can change during aging.

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

ABSTRACTSex 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.IMPORTANCESex 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.