Involvement of the Akt/NF-κB pathways in the HTNV-mediated increase of IL-6, CCL5, ICAM-1, and VCAM-1 in HUVECs

Cardamonin inhibits the expression of inflammatory mediators in TNF-α-stimulated human periodontal ligament cells

OBJECTIVE

Periodontis is a chronic inflammatory disease induced by periodontopathogenic bacteria. The excessive immune response caused by persistent bacterial infection leads to alveolar bone resorption and ultimately tooth loss. Cardamonin is a biologically active substance that is found in the Zingiberaceae family, such as Alpinia zerumbet, and is classified as a natural chalcone. There have been no attempts to use cardamonin for the treatment of periodontitis, and no reports have examined the effects of cardamonin on periodontal tissue component cells. The aim of this study was to analyze effects of cardamonin on expression of inflammation mediators produced by TNFα-stimulated human periodontal ligament cells (HPDLCs), including its effects on signal transduction molecules.

METHODS

Cytokine and chemokine levels were measured by ELISA. Protein expression in HPDLCs and activations of signal transduction pathway were determined by Western blotting.

RESULTS

Our results indicate that cardamonin suppresses C-C motif chemokine ligand (CCL)2, CCL20, C-X-C motif chemokine ligand (CXCL)10, and interleukin (IL)-6 production and intercellular adhesion molecule (ICAM)-1 and cyclooxygenase (COX)-2 expression in TNF-α-stimulated HPDLCs. In addition, cardamonin induced the expression of the antioxidant enzyme, Heme Oxygenase (HO)-1, in HPDLCs. Furthermore, cardamonin suppressed TNF-α-stimulated c-Jun N-terminal kinase (JNK), nuclear factor (NF)-κB, and signal transducer and activator of transcription (STAT)3 signaling pathways in HPDLCs.

CONCLUSION

We show that cardamonin reduces inflammatory mediator production by inhibiting the activation of several signaling pathways in this manuscript.

Cardamonin decreases inflammatory mediator expression in IL-1β-stimulated human periodontal ligament cells

BACKGROUND

Cardamonin is classified as a natural chalcone, and has been reported to possess various bioactive effects. However, there have been limited attempts to utilize cardamonin in the treatment of periodontitis. This study aimed to investigate whether cardamonin has anti-inflammatory effects on human periodontal ligament cells (HPDLCs), which are a component cell of periodontal tissue. Specifically, the study seeks to determine whether cardamonin affects the expression of inflammatory mediators, such as cytokines and adhesion molecules, induced by interleukin-1β (IL-1β) in HPDLCs, as well as the signaling pathways activated by IL-1β.

METHODS

Cytokine and chemokine levels in supernatants of HPDLCs were measured by ELISA. Western blot analysis was used to measure protein expression and signal transduction pathway activation in HPDLCs.

RESULTS

We found that IL-1β-induced CC chemokine ligand (CCL)2, CCL5, CCL20, CXC-chemokine ligand (CXCL)10, and interleukin (IL)-6 production and intercellular adhesion molecule (ICAM)-1 and cyclooxygenase (COX)-2 expression in HPDLCs were suppressed by cardamonin treatment. We also found that cardamonin suppressed IL-1β-activated nuclear factor (NF)-κB pathway, and the phosphorylation of signal transducer and activator of transcription (STAT)3. Furthermore, cardamonin treatment enhanced the expression of the antioxidant enzymes, heme oxygenase (HO)-1 and NAD(P)H dehydrogenase [quinone] 1 (NQO1), in HPDLCs.

CONCLUSION

In this study, we found that cardamonin could suppress the production of inflammatory mediators in HPDLCs as well as the activation of several signaling pathways induced by IL-1β treatment.

Disparate macrophage responses are linked to infection outcome of Hantan virus in humans or rodents

Hantaan virus (HTNV) is asymptomatically carried by rodents, yet causes lethal hemorrhagic fever with renal syndrome in humans, the underlying mechanisms of which remain to be elucidated. Here, we show that differential macrophage responses may determine disparate infection outcomes. In mice, late-phase inactivation of inflammatory macrophage prevents cytokine storm syndrome that usually occurs in HTNV-infected patients. This is attained by elaborate crosstalk between Notch and NF-κB pathways. Mechanistically, Notch receptors activated by HTNV enhance NF-κB signaling by recruiting IKKβ and p65, promoting inflammatory macrophage polarization in both species. However, in mice rather than humans, Notch-mediated inflammation is timely restrained by a series of murine-specific long noncoding RNAs transcribed by the Notch pathway in a negative feedback manner. Among them, the lnc-ip65 detaches p65 from the Notch receptor and inhibits p65 phosphorylation, rewiring macrophages from the pro-inflammation to the pro-resolution phenotype. Genetic ablation of lnc-ip65 leads to destructive HTNV infection in mice. Thus, our findings reveal an immune-braking function of murine noncoding RNAs, offering a special therapeutic strategy for HTNV infection.

Hemorrhagic fever with renal syndrome caused by destruction of residential area of rodent in a construction site: epidemiological investigation

BACKGROUND

An outbreak of hemorrhagic fever with renal syndrome (HFRS), caused by a Hantavirus, affected nine adult males in the southwest area of Xi'an in November 2020 was analyzed in this study.

METHODS

Clinical and epidemiological data of HFRS patients in this outbreak were retrospectively analyzed. The whole genome of a hantavirus named 201120HV03xa (hv03xa for short) isolated from Apodemus agrarius captured in the construction site was sequenced and analyzed. In addition, nine HFRS patients were monitored for the IgG antibody against the HV N protein at 6 and 12 months, respectively.

RESULTS

In this study, inhalation of aerosolized excreta and contaminated food may be the main source of infection. Genome analysis and phylogenetic analysis showed that hv03xa is a reassortment strain of HTNV, having an S segment related to A16 of HTN 4, an M segment related to Q37 and Q10 of HTN 4, and an L segment related to prototype strain 76-118 of HTN 7. Potential recombination was detected in the S segment of hv03xa strain. The anti-HV-IgG level of all the patients persist for at least one year after infection.

CONCLUSIONS

This report documented an HFRS outbreak in Xi'an, China, which provided the basic data for epidemiological surveillance of endemic HTNV infection and facilitated to predict disease risk and implement prevention measures.

In vitro Anti-Hantavirus Activity of Protein Kinase Inhibitor 8G1 Targeting AKT/mTOR/eIF4E Signaling Pathway

Hantaan virus (HTNV) is the main cause of hemorrhagic fever with renal syndrome (HFRS) around the world, which results in profound morbidity and mortality. However, there are currently no FDA-approved therapeutics or vaccines against HFRS. To find new anti-HTNV drugs, the inhibitory activity of 901 small molecule kinase inhibitors against HTNV is analyzed. Among these compounds, compound 8G1 inhibits HTNV with a relatively high inhibition rate and lower toxicity. The viral titer and nucleocapsid protein of HTNV are reduced after compound 8G1 treatment in a dose-dependent manner at concentrations ranging from 1 to 20 μM. In addition, the administration of compound 8G1 at the early stage of HTNV infection can inhibit the replication of HTNV. The molecular docking result reveals that compound 8G1 forms interactions with the key amino acid residues of serine/threonine-protein kinase B (Akt), which is responsible for the observed affinity. Then, the mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E (eIF4E) signaling pathways are inhibited. Our results may help to design novel targets for therapeutic intervention against HTNV infection and to understand the anti-HTNV mechanism of protein kinase inhibitors.

Elevated Plasma Fractalkine Level Is Associated with the Severity of Hemorrhagic Fever with Renal Syndrome in Humans

Hantaan virus infection may cause severe lethal hemorrhagic fever with renal syndrome (HFRS) in humans. The chemokine fractalkine (CX3CL1) acts as a proinflammatory cytokine, and it is elevated in several infectious diseases. However, little is known about the contributions of CX3CL1 to HFRS pathogenesis. Present study detected plasma CX3CL1 levels and expression of the receptor CX3CR1 in HFRS patients and discussed the possible effects of CX3CL1 on pathogenesis of HFRS. Plasma CX3CL1 in acute phase and Critical/Severe groups of HFRS patients were significantly increased compared to that in normal controls (p < 0.001 and p < 0.01, respectively). High plasma CX3CL1 was negatively correlated with platelet count (r = -0.5844, p < 0.0001) and positively correlated with blood urea nitrogen (r = 0.3668, p = 0.0039), creatinine (r = 0.42, p = 0.0008), and white blood cells (r = 0.2646, p = 0.0411). Expression of CX3CR1 on nonclassical and intermediate monocytes was also increased in the acute phase (p < 0.01 for both the cells) and Critical/Severe groups (p < 0.05 and p < 0.01, respectively) of HFRS patients compared to that in normal controls. Taken together, elevation of plasma CX3CL1 in HFRS patients and expression of CX3CR1 on nonclassical and intermediate monocyte subsets might provide new insights into the potential role of CX3CL1/CX3CR1 in pathogenesis of HFRS.

Ethanolic extract of Artemisia campestris subsp. glutinosa (Besser) Batt. inhibits HIV-1 replication in vitro through the activity of terpenes and flavonoids on viral entry and NF-κB pathway

ETHNO-PHARMACOLOGICAL RELEVANCE

The genus Artemisia spp. is well known for its anti-infectious properties and its high content in anti-infectious compounds, like the well-known sweet wormwood (Artemisia annua L.). Another Artemisia species, Artemisia campestris subsp. glutinosa (Besser) Batt., field wormwood, has been traditionally used as medicinal plant in the Mediterranean region.

AIM OF THE STUDY

The aim of this study is to investigate the anti-HIV activity of field wormwood, to identify the compounds responsible for this activity and their structure and mechanism of action.

MATERIALS AND METHODS

Antiviral activity of isolated compounds and extracts was evaluated in HIV-1 infections of lymphoblastoid cells. We also evaluated the mechanism of action of isolated compounds. Viral entry was studied comparing the inhibitory effect of isolated compounds on wild type HIV-1 and VSV pseudotyped HIV-1. To assess the viral transcriptional effect, plasmids encoding luciferase reporter genes under the control of the whole genome of HIV-1 or NF-κB or Sp1 transcription factors were transfected in the presence of the compounds under evaluation. Finally, antioxidant activity was assessed by quantitation of reduced and total glutathione in treated cell cultures.

RESULTS

Ethanolic and aqueous extracts of Artemisia campestris subsp. glutinosa (Besser) Batt. subsp. glutinosa displayed anti-HIV activity in vitro, although ethanolic extract was more powerful (IC₅₀ 14.62 μg/mL). Bio-guided ethanolic extract fractionation leads to the isolation and characterization of two terpenes, damsin and canrenone, and four flavonoids, 6, 2', 4'-trimethoxyflavone, acerosin, cardamonin and xanthomicrol. All the isolated compounds inhibited HIV-1 replication in vitro with IC₅₀ values between the middle nanomolar and the low micromolar range. Their anti-HIV mechanism of action is due to the bloking of viral entry and/or transcription inhibition, without correlation with the antioxidant activity, through interference with the cellular transcription factors NF-κB and Sp1, which are targets that are not currently reached by antiretroviral therapy.

CONCLUSION

We describe here the anti-HIV activity of field wormwood, Artemisia campestris subsp. glutinosa (Besser) Batt., and the isolation and study of the mechanism of action of two terpenes and four flavonoids, responsible, at least in part, for its activity, through the inhibition of two different cellular targets affecting the HIV replication cycle. The activity of these compounds in cellular targets could explain why plant extracts can be used in the treatment of different diseases. Besides, the presence of several compounds with dual and different mechanisms of action could prove useful in the treatment of HIV-1 infection, since it could aid to overcome drug resistances and simplify drug therapy. This work is a further step in understanding the anti-infectious activity of wormwood species and their use in treating infectious diseases.

9t18:1 and 11t18:1 activate the MAPK pathway to regulate the expression of PLA2 and cause inflammation in HUVECs

trans fatty acids (TFAs) have been reported to promote vascular diseases mainly by promoting apoptosis and inflammation of vascular endothelial cells. However, it has been reported in recent years that elaidic acid (9t18:1) and vaccenic acid (11t18:1) may have different effects on vascular health. This study investigated the effects of 9t18:1 and 11t18:1 on human umbilical vein endothelial cell (HUVEC) function and the possible mechanism of inflammation by analyzing the changes in the phospholipid composition and the relationship between phospholipase A2 (PLA2) and MAPK pathway. Here we found that the effect of 11t18:1 on cell viability, membrane damage and cellular inflammation was significantly lower than that of 9t18:1 (p < 0.05). And 9t18:1 and 11t18:1 had different effects on phospholipid composition. Both 9t18:1 and 11t18:1 significantly increased the protein expression of PLA2. Moreover, the MAPK pathway regulated the expression of PLA2, inflammatory cytokines and cyclooxygenase-2 (COX-2) and the secretion of prostaglandin E2 (PGE2) in HUVECs induced by 9t18:1 and 11t18:1. In conclusion, 9t18:1 and 11t18:1 activated the MAPK pathway which regulated the expression of PLA2 to cause inflammation in HUVECs.

Investigation on risk factors of haemorrhagic fever with renal syndrome (HFRS) in Xuancheng City in Anhui Province, Mainland China

Haemorrhagic fever with renal syndrome (HFRS), a rodent-borne disease, is a major public health concern in both developed and developing countries. China is the most severe endemic country in the world, constituting 90% of the cases. Although the incidence of HFRS has substantively decreased in most areas of China, HFRS has rebounded remarkably in some epidemic areas. Xuancheng is one of these areas. In this study, we collected the case data reported recently in Xuancheng and designed a 1:3 case-control study. The Chi-square test, univariate and multivariate logistic regression analysis were performed. In all cases, farmers made up the highest proportion of occupations. And there were 20 variables with statistical significance including indoor hygienic conditions; the surrounding environment; whether bitten by rats at work and other criteria. In addition, exposure to rodents and rats bites is a high-risk factor for HFRS. Rodent density was calculated at 20.9% (159/760), the virus carrier rate was 9.4% (15/159) and the index of rats with a virus was about 2.0%. Exposure to rodents and insect bites is also high-risk factors for HFRS among local residents in Xuancheng. More importantly, during the flood years, the increased density of rodents led to an increased risk of human exposure to rodents. As our statistical analysis proves, targeted strategies should be developed and implemented to reduce the incidence of local diseases in the future.

RNA-Seq Revealed a Circular RNA-microRNA-mRNA Regulatory Network in Hantaan Virus Infection

Hantaan virus (HTNV), a Hantavirus serotype that is prevalent in Asia, causes hemorrhagic fever with renal syndrome (HFRS) with high mortality in human race. However, the pathogenesis of HTNV infection remains elusive. Circular RNAs (circRNAs), a new type of non-coding RNAs, play a crucial role in various pathogenic processes. Nevertheless, circRNA expression profiles and their effects on pathogenesis of HTNV infection are still completely unknown. In the present study, RNA sequencing was performed to analyze the circRNA, microRNA (miRNA), and mRNA expression profiles in HTNV-infected and mock-infected human umbilical vein endothelial cells (HUVECs). A total of 70 circRNAs, 66 miRNAs, and 788 mRNAs were differently expressed. Several differentially expressed RNAs were validated by RT-qPCR. Moreover, we verified that some differentially expressed RNAs, such as circ_0000479, miR-149-5p, miR-330-5p, miR-411-3p, RIG-I, CMPK2, PARP10, and GBP1, promoted or inhibited HTNV replication. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis demonstrated that the host genes of differentially expressed circRNAs were principally involved in the innate immune response, the type I interferon (IFN) signaling pathway, and the cytokine-mediated signaling pathway. Additionally, the circRNA-miRNA-mRNA regulatory network was integrally analyzed. The data showed that there were many circRNA-miRNA-mRNA interactions in HTNV infection. By dual-luciferase reporter assay, we confirmed that circ_0000479 indirectly regulated RIG-I expression by sponging miR-149-5p, hampering viral replication. This study for the first time presents a comprehensive overview of circRNAs induced by HTNV and reveals that a network of enriched circRNAs and circRNA-associated competitive endogenous RNAs (ceRNAs) is involved in the regulation of HTNV infection, thus offering new insight into the mechanisms underlying HTNV-host interaction.

Type I collagen promotes the migration and myogenic differentiation of C2C12 myoblastsviathe release of interleukin-6 mediated by FAK/NF-κB p65 activation

Type I collagen has the potential to promote the migration and differentiation of C₂C₁₂myoblastviaIL-6 release that was mediated by FAK/NF-κB pathway.

HTNV-induced upregulation of miR-146a in HUVECs promotes viral infection by modulating pro-inflammatory cytokine release

Increasing research has shown a link between viruses and miRNAs, such as miRNA-146a, in regulating virus infection and replication. In the current study, the association between miR-146a and hantaan virus (HTNV) infection in human umbilical vein endothelial cells (HUVECs) was investigated, with a focus on examining the expression of pro-inflammatory cytokines. The results showed that HTNV infection promoted the production of miR-146a in HUVECs and activated nuclear factor-κB (NF-κB) signaling, along with the upregulation of pro-inflammatory cytokines, including interleukin 8 (IL-8), C-C Motif Chemokine Ligand 5 (CCL5, also RANTES), interferon-inducible protein-10 (IP-10) and interferon beta (IFN-β). Moreover, miR-146a exhibited a negative regulatory effect on the NF-κB pathway. Accordingly, a miR-146a inhibitor increased the expression of IL-8, CCL5, IP-10 and IFN-β, whereas a miR-146a mimic reduced the levels of these cytokines. Consequently, exogenous transduction of miR-146a significantly enhanced HTNV replication in HUVEC cells. We also discovered that viral proteins (NP/GP) contributed to miR-146a expression via enhancement the activity of miR-146a promoter. In conclusion, these results imply the negative regulation of miR-146a on the production of HTNV-induced pro-inflammatory cytokines contributes to virus replication, which suggest that miR-146a may be regarded as a novel therapeutic target for HTNV infection.

Performance assessment of the SAPS II and SOFA scoring systems in Hanta virus Hemorrhagic Fever with Renal Syndrome

BACKGROUND

Hemorrhagic Fever with Renal Syndrome (HFRS), caused by the hantavirus, is a natural infectious disease characterized by fever, hemorrhage and renal damage. China is the most severely endemic area for HFRS in the world. In recent years, critical scoring systems based on quantitative classification have become an important clinical tool for predicting and evaluating the prognosis of critical illness, and provide guidelines for clinical practice.

METHODS

The sample comprised 384 patients with HFRS treated in the Taizhou Hospital from January 2006 to February 2017. The patients were divided into the severe group and the mild group according to their clinical characteristics. By comparing the differences in clinical symptoms, signs and laboratory data between the two groups, the clinically relevant indicators of severe HFRS were explored. According to the previous studies, we incorporated the positive fecal occult blood test (FOBT) into the sepsis-related organ failure assessment (SOFA) tool and formulated a new scoring system specifically for HFRS, named H-SOFA. By comparing the simplified acute physiology score II (SAPS II), SOFA and H-SOFA scores of the two groups, their predictive values for the progression of HFRS were assessed.

RESULTS

Compared to the mild group, patients in the severe group had longer hospital stays; higher frequencies of nausea, vomiting, abdomen pain, signs of congestion and hemorrhage; and more pronounced impairment of liver and renal function. The levels of PLT, PCT, TB, and FOBT were positively correlated with the progression of HFRS (P<0.001). Patients with HFRS in the severe group got significantly higher scores on the SAPS II, SOFA, and H-SOFA scoring systems (P<0.001). The values of SAPS II, SOFA and H-SOFA, were significantly correlated with the severity of HFRS, and the AUC values were 0.90, 0.96, and 0.98, respectively.

CONCLUSION

PLT, PCT, TB, and FOBT were independent predictors of severe HFRS; SAPS II, SOFA, and H-SOFA had high predictive value for the progression of severe HFRS, with H-SOFA being the highest.

Hantavirus infection: a global zoonotic challenge

Hantaviruses are comprised of tri-segmented negative sense single-stranded RNA, and are members of the Bunyaviridae family. Hantaviruses are distributed worldwide and are important zoonotic pathogens that can have severe adverse effects in humans. They are naturally maintained in specific reservoir hosts without inducing symptomatic infection. In humans, however, hantaviruses often cause two acute febrile diseases, hemorrhagic fever with renal syndrome (HFRS) and hantavirus cardiopulmonary syndrome (HCPS). In this paper, we review the epidemiology and epizootiology of hantavirus infections worldwide.

Interferon-Induced Transmembrane Protein 3 Inhibits Hantaan Virus Infection, and Its Single Nucleotide Polymorphism rs12252 Influences the Severity of Hemorrhagic Fever with Renal Syndrome

Hantaan virus (HTNV) causes hemorrhagic fever with renal syndrome (HFRS). Previous studies have identified interferon-induced transmembrane proteins (IFITMs) as an interferon-stimulated gene family. However, the role of IFITMs in HTNV infection is unclear. In this study, we observed that IFITM3 single nucleotide polymorphisms (SNP) rs12252 C allele and CC genotype associated with the disease severity and HTNV load in the plasma of HFRS patients. In vitro experiments showed that the truncated protein produced by the rs12252 C allele exhibited an impaired anti-HTNV activity. We also proved that IFITM3 was able to inhibit HTNV infection in both HUVEC and A549 cells by overexpression and RNAi assays, likely via a mechanism of inhibiting virus entry demonstrated by binding and entry assay. Localization of IFITM3 in late endosomes was also observed. In addition, we demonstrated that the transcription of IFITM3 is negatively regulated by an lncRNA negative regulator of interferon response (NRIR). Taken together, we conclude that IFITM3, negatively regulated by NRIR, inhibits HTNV infection, and its SNP rs12252 correlates with the plasma HTNV load and the disease severity of patients with HFRS.

What Do We Know about How Hantaviruses Interact with Their Different Hosts?

Hantaviruses, like other members of the Bunyaviridae family, are emerging viruses that are able to cause hemorrhagic fevers. Occasional transmission to humans is due to inhalation of contaminated aerosolized excreta from infected rodents. Hantaviruses are asymptomatic in their rodent or insectivore natural hosts with which they have co-evolved for millions of years. In contrast, hantaviruses cause different pathologies in humans with varying mortality rates, depending on the hantavirus species and its geographic origin. Cases of hemorrhagic fever with renal syndrome (HFRS) have been reported in Europe and Asia, while hantavirus cardiopulmonary syndromes (HCPS) are observed in the Americas. In some cases, diseases caused by Old World hantaviruses exhibit HCPS-like symptoms. Although the etiologic agents of HFRS were identified in the early 1980s, the way hantaviruses interact with their different hosts still remains elusive. What are the entry receptors? How do hantaviruses propagate in the organism and how do they cope with the immune system? This review summarizes recent data documenting interactions established by pathogenic and nonpathogenic hantaviruses with their natural or human hosts that could highlight their different outcomes.

Aging-associated oxidized albumin promotes cellular senescence and endothelial damage

Increased levels of oxidized proteins with aging have been considered a cardiovascular risk factor. However, it is unclear whether oxidized albumin, which is the most abundant serum protein, induces endothelial damage. The results of this study indicated that with aging processes, the levels of oxidized proteins as well as endothelial microparticles release increased, a novel marker of endothelial damage. Among these, oxidized albumin seems to play a principal role. Through in vitro studies, endothelial cells cultured with oxidized albumin exhibited an increment of endothelial damage markers such as adhesion molecules and apoptosis levels. In addition, albumin oxidation increased the amount of endothelial microparticles that were released. Moreover, endothelial cells with increased oxidative stress undergo senescence. In addition, endothelial cells cultured with oxidized albumin shown a reduction in endothelial cell migration measured by wound healing. As a result, we provide the first evidence that oxidized albumin induces endothelial injury which then contributes to the increase of cardiovascular disease in the elderly subjects.

Hemorrhagic Fever with Renal Syndrome: Pathogenesis and Clinical Picture

Hantaan virus (HTNV) causes hemorrhagic fever with renal syndrome (HFRS), which is a zoonosis endemic in eastern Asia, especially in China. The reservoir host of HTNV is field mouse (Apodemus agraricus). The main manifestation of HFRS, including acute kidney injury, increases vascular permeability, and coagulation abnormalities. In this paper, we review the current knowledge of the pathogenesis of HFRS including virus factor, immunity factor and host genetic factors. Furthermore, the treatment and prevention will be discussed.

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.

SRY gene transferred by extracellular vesicles accelerates atherosclerosis by promotion of leucocyte adherence to endothelial cells

We set out to investigate whether and how SRY (sex-determining region, Y) DNAs in plasma EVs (extracellular vesicles) is involved in the pathogenesis of atherosclerosis. PCR and gene sequencing found the SRY gene fragment in plasma EVs from male, but not female, patients; EVs from male patients with CAD (coronary artery disease) had a higher SRY GCN (gene copy number) than healthy subjects. Additional studies found that leucocytes, the major source of plasma EVs, had higher SRY GCN and mRNA and protein expression in male CAD patients than controls. After incubation with EVs from SRY-transfected HEK (human embryonic kidney)-293 cells, monocytes (THP-1) and HUVECs (human umbilical vein endothelial cells), which do not endogenously express SRY protein, were found to express newly synthesized SRY protein. This resulted in an increase in the adherence factors CD11-a in THP-1 cells and ICAM-1 (intercellular adhesion molecule 1) in HUVECs. EMSA showed that SRY protein increased the promoter activity of CD11-a in THP-1 cells and ICAM-1 in HUVECs. There was an increase in THP-1 cells adherent to HUVECs after incubation with SRY-EVs. SRY DNAs transferred from EVs have pathophysiological significance in vivo; injection of SRY EVs into ApoE−/− (apolipoprotein-knockout) mice accelerated atherosclerosis. The SRY gene in plasma EVs transferred to vascular endothelial cells may play an important role in the pathogenesis of atherosclerosis; this mechanism provides a new approach to the understanding of inheritable CAD in men.

Hantavirus-induced disruption of the endothelial barrier: neutrophils are on the payroll

Viral hemorrhagic fever caused by hantaviruses is an emerging infectious disease for which suitable treatments are not available. In order to improve this situation a better understanding of hantaviral pathogenesis is urgently required. Hantaviruses infect endothelial cell layers in vitro without causing any cytopathogenic effect and without increasing permeability. This implies that the mechanisms underlying vascular hyperpermeability in hantavirus-associated disease are more complex and that immune mechanisms play an important role. In this review we highlight the latest developments in hantavirus-induced immunopathogenesis. A possible contribution of neutrophils has been neglected so far. For this reason, we place special emphasis on the pathogenic role of neutrophils in disrupting the endothelial barrier.

IL-33/ST2 correlates with severity of haemorrhagic fever with renal syndrome and regulates the inflammatory response in Hantaan virus-infected endothelial cells

BACKGROUND

Hantaan virus (HTNV) causes a severe lethal haemorrhagic fever with renal syndrome (HFRS) in humans. Despite a limited understanding of the pathogenesis of HFRS, the importance of the abundant production of pro-inflammatory cytokines has been widely recognized. Interleukin 33 (IL-33) has been demonstrated to play an important role in physiological and pathological immune responses. After binding to its receptor ST2L, IL-33 stimulates the Th2-type immune response and promotes cytokine production. Depending on the disease model, IL-33 either protects against infection or exacerbates inflammatory disease, but it is unknown how the IL-33/ST2 axis regulates the immune response during HTNV infection.

METHODOLOGY/PRINCIPAL FINDINGS

Blood samples were collected from 23 hospitalized patients and 28 healthy controls. The levels of IL-33 and soluble ST2 (sST2) in plasma were quantified by ELISA, and the relationship between IL-33, sST2 and the disease severity was analyzed. The role of IL-33/sST2 axis in the production of pro-inflammatory cytokines was studied on HTNV-infected endothelial cells. The results showed that the plasma IL-33 and sST2 were significantly higher in patients than in healthy controls. Spearman analysis showed that elevated IL-33 and sST2 levels were positively correlated with white blood cell count and viral load, while negatively correlated with platelet count. Furthermore, we found that IL-33 enhanced the production of pro-inflammatory cytokines in HTNV-infected endothelial cells through NF-κB pathway and that this process was inhibited by the recombinant sST2.

CONCLUSION/SIGNIFICANCE

Our results indicate that the IL-33 acts as an initiator of the "cytokine storm" during HTNV infection, while sST2 can inhibit this process. Our findings could provide a promising immunotherapeutic target for the disease control.