CXCL10 Chemokine: A Critical Player in RNA and DNA Viral Infections

AGR2-mediated cell-cell communication controls the antiviral immune response by promoting the thiol oxidation of TRAF3

Protein disulfide isomerases (PDIs) are essential catalysts for the formation and isomerization of disulfide bonds in diverse substrate proteins and exert multiple functions under pathophysiological conditions. Here, we show that anterior gradient 2 (AGR2), a member of PDIs, acts as a negative regulator in antiviral immunity. RNA virus infection stimulated the expression and secretion of AGR2 in epithelial cells. While AGR2 is absent in immune cells, both intracellular AGR2 and extracellular AGR2 compromised type I interferon (IFN-I) production in vitro and in vivo. The inhibitory effect of secreted AGR2 on the immune response resulted from its crosstalk with immune cells, such as macrophages, by which eAGR2 was internalized via endocytosis depending on its adhesion motif. We further identified AGR2 as a novel binding protein of TRAF3, which forms a disulfide bond between Cys81 of AGR2 and Cys296 on TRAF3. This interaction led to the inhibition of TRAF3 K63-linked ubiquitination and TRAF3-TBK1 complex formation, ultimately impairing TRAF3's ability to induce IFN-I production. The TRAF3 Cys296 mutation diminishes oxidative modification by AGR2 but enhances self-association of TRAF3 and IFN-I production. Our study demonstrated a cysteine-dependent oxidative modification of TRAF3 by AGR2 that suppresses TRAF3 activity and maintains innate immune homeostasis.

Addition of metformin to anti-PD-1/PD-L1 drugs activates anti-tumor immune response in peripheral immune cells of NSCLC patients

Immunotherapy has transformed the treatment landscape for non-small cell lung cancer (NSCLC), yet achieving lasting benefits remains a challenge. The resistance mechanisms to immunotherapy are complex, involving interactions between tumor cells and immune cells that are not fully understood. Metformin, an FDA-approved diabetes medication, shows promise in enhancing immunotherapy efficacy by boosting anti-tumor immune responses, although the underlying molecular pathways are still being investigated. This study utilized co-culture models of cancer and immune cells to explore the effects of combining metformin with anti-PD-1/PD-L1 therapies on the anti-tumor immune response in LKB1 mutant (LKB1mut) versus wild-type (LKB1wt) NSCLC cells, alongside peripheral blood immune cells from NSCLC patients. The transcriptomic profiles of LKB1mut and LKB1wt NSCLC cells were characterized via bulk RNA sequencing to understand gene expression changes induced by metformin. Patients with advanced-stage NSCLC provided peripheral blood mononuclear cells (PBMCs) for analysis. The study assessed metformin's impact both alone and in combination with anti-PD-1/PD-L1 agents on innate immune pathways. Results indicated that metformin activated the cGAS-STING pathway and interferons in PBMCs, enhancing their anti-tumor capabilities. Notably, immune cells treated with metformin and immunotherapy exhibited synergistic effects, significantly reducing colony formation in LKB1mut NSCLC cells. Additionally, monocytes from NSCLC patients showed decreased viability of NSCLC cells in co-culture, independent of LKB1 status, and shifted towards an anti-tumor M1 phenotype with combined treatment. These findings were supported by 3D co-culture models involving tumor spheroids and patient-derived organoids, highlighting a novel biological rationale for using metformin alongside immunotherapeutic agents to boost anti-tumor activity across various immune cell subsets derived from NSCLC patients.

Investigating potential drug targets for the treatment of glioblastoma: a Mendelian randomization study

Glioblastoma (GBM), one of the most aggressive brain tumors, has a 5-year survival rate of less than 5%. Current standard therapies, including surgery, radiotherapy, and temozolomide (TMZ) chemotherapy, are limited by drug resistance and the blood-brain barrier. Integrating expression quantitative trait loci (eQTL) and protein quantitative trait loci (pQTL) data has shown promise in uncovering disease mechanisms and therapeutic targets. This study combined eQTL and pQTL analyses to identify potential GBM-related genes and circulating plasma proteins for therapeutic exploration. Using transcriptomic data from The Cancer Genome Atlas (TCGA), we identified 2,528 differentially expressed genes, including GPX7 and CXCL10. eQTL-MR analysis identifies GBM-associated differentially expressed genes and constructs a protein-protein interaction (PPI) network.Integrating pQTL data from the deCODE database, pQTL-MR, and colocalization analyses validated the therapeutic potential of GPX7 and CXCL10.These findings provide new perspectives on GBM biology and suggest actionable targets for therapy. Despite limitations due to sample size and population-specific data, this study highlights GPX7 and CXCL10 as promising candidates for further investigation and lays the foundation for targeted GBM treatments.

Maternal immune activation elicits rapid and sex-dependent changes in gene expression and vascular dysfunction in the rat placenta

INTRODUCTION

Maternal immune activation (MIA), characterized by increased circulating inflammatory mediators during pregnancy, is associated with adverse pregnancy outcomes and neurodevelopmental deficits in offspring. These health outcomes often manifest differently depending on fetal-placental sex. A well-established model of MIA involves administration of a viral mimetic, polyinosinic:polycytidilic acid (PolyI:C), to pregnant rodents. Placental responses to PolyI:C contribute to the detrimental effects of MIA on offspring, but these responses have not yet been well characterized. In the present study, we profiled acute gene expression changes in male and female placentas following PolyI:C administration to pregnant rats during late gestation.

METHODS

Pregnant rats received 4 mg/kg PolyI:C or saline intravenously on gestational day 18.5, and tissues were harvested 4-5 h later. Gene expression profiling on placental tissue was performed. Enzyme immunoassays and immunohistochemistry were conducted to determine levels of select proteins in maternal blood and placental tissue, respectively.

RESULTS

Maternal PolyI:C exposure caused a robust increase in levels of inflammatory mediators in maternal blood and placental tissue. There were more genes differentially expressed in female placentas after PolyI:C exposure (765) than male placentas (221), including reduced expression of genes associated with maternal-fetal communication. Placentas also had increased expression of genes linked with vascular dysfunction after PolyI:C-induced MIA.

DISCUSSION

PolyI:C elicited a powerful inflammatory response in the placenta along with vascular dysfunction, likely contributing to the adverse pregnancy outcomes triggered by MIA. Female placentas responded to PolyI:C more vigorously than male placentas, which could underlie the differential outcomes of MIA depending on sex.

Cxcl10 is protective during mouse-adapted SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the coronavirus disease 2019 (COVID-19) pandemic, remains endemic worldwide. Circulating levels of the chemokine CXCL10 are strongly positively associated with poor outcome; however, its precise role in SARS-CoV-2 pathogenesis and its suitability as a therapeutic target have remained undefined. Here, we challenged mice genetically deficient in Cxcl10 with a mouse-adapted strain of SARS-CoV-2. Infected male, but not female, Cxcl10-/- mice displayed increased mortality compared to wild type controls. Histopathological damage, inflammatory gene induction, and virus load in the lungs of male mice were not broadly influenced by Cxcl10 deficiency. However, accumulation of B and T lymphocytes in the lung parenchyma of infected mice was reduced in the absence of Cxcl10. Thus, during acute SARS-CoV-2 infection, Cxcl10 regulates lymphocyte infiltration in lung and confers protection against mortality. Our preclinical model results do not support targeting CXCL10 therapeutically in severe COVID-19.

Harnessing immunotherapeutic molecules and diagnostic biomarkers as human-derived adjuvants for MERS-CoV vaccine development

The pandemic potential of the Middle East Respiratory Syndrome Coronavirus (MERS-CoV) highlights the critical need for effective vaccines due to its high fatality rate of around 36%. In this review, we identified a variety of immunotherapeutic molecules and diagnostic biomarkers that could be used in MERS vaccine development as human-derived adjuvants. We identified immune molecules that have been incorporated into standard clinical diagnostics such as CXCL10/IP10, CXCL8/IL-8, CCL5/RANTES, IL-6, and the complement proteins Ca3 and Ca5. Utilization of different human monoclonal antibodies in the treatment of MERS-CoV patients demonstrates promising outcomes in combatting MERS-CoV infections in vivo, such as hMS-1, 4C2H, 3B11-N, NBMS10-FC, HR2P-M2, SAB-301, M336, LCA60, REGN3051, REGN3048, MCA1, MERs-4, MERs-27, MERs-gd27, and MERs-gd33. Host-derived adjuvants such as CCL28, CCL27, RANTES, TCA3, and GM-CSF have shown significant improvements in immune responses, underscoring their potential to bolster both systemic and mucosal immunity. In conclusion, we believe that host-derived adjuvants like HBD-2, CD40L, and LL-37 offer significant advantages over synthetic options in vaccine development, underscoring the need for clinical trials to validate their efficacy.

IFN-γ Induces Pleural Mesothelial Cells to Recruit Immune Cells via CXCL10-CXCR3 Axis in a Mouse Pleurisy Model

Background

Pleural mesothelial cells (PMCs) form the entire surface of the pleural cavity and interact with microorganisms in the thorax. Although PMCs are known to exert multiple immune functions, their role in pleurisy remains unclear.

Methods

Pleurisy model was induced by intrapleural injection of Mycobacterium bovis bacillus Calmette-Guerin (BCG) into wild-type (WT) C57BL/6 mice. The pleural cavity was washed with Phosphate Buffered Saline (PBS) to get the immune cells. Flow cytometry was performed to identify the characteristics of the target cells.

Results

We found that IFN-γ prompts PMCs to act a summon role for the recruitment of inflammatory cells in pleurisy model. Our data showed that CD4+ T cells were the main producer of IFN-γ in the pleurisy model, and IFN-γ stimulated PMCs to recruit immune cells into the pleural cavity through the CXCL10-CXCR3 axis. In addition, IFN-γ can reshape PMCs to display macrophage-like polarization. These results revealed some new immune roles of PMCs in pleurisy.

Conclusion

In a mouse model of pleurisy, IFN-γ, which is mainly derived from CD4+ T cells, promoted PMCs to recruit of immune cells into the pleural cavity and exhibited macrophage-like polarization.

Hemostatic Profile and Serum Levels of Interferon Gamma-Induced Protein 10 (IP-10) in Neonates Born to Mothers with COVID-19 During the Peripartum Period

The COVID-19 pandemic has raised significant concerns regarding its potential impact on maternal and neonatal health. This study aimed to investigate the immunologic and hemostatic profiles of neonates exposed to SARS-CoV-2 during the peripartum period (0-14 days prior to delivery). This retrospective study included 28 neonates born to COVID-19-positive mothers during the peripartum period and a control group of 54 neonates born to mothers who never tested positive for SARS-CoV-2 during pregnancy. Arterial blood samples were collected from all neonates on the second day of life for the simultaneous assessment of full blood count, C-reactive protein (CRP), serum interleukin-6 (IL-6), and Interferon gamma-induced protein 10 (IP-10) levels, as well as Rotational Thromboelastometry (ROTEM) tests (EXTEM, INTEM, and NATEM). Neonates born to COVID-19-positive mothers and those born to COVID-19-negative mothers exhibited similar coagulation profiles based on ROTEM analysis. Multiple linear regression analysis revealed that peripartum COVID-19 infection was associated with higher IP-10 levels in neonates (coefficient: +16.8, 95% CI: +9.0 to +24.6, p < 0.0001). Our study findings suggest that the presence of immunologic disturbance in neonates is related to recent peripartum exposure to maternal SARS-CoV-2 infection, as evidenced by increased IP-10 levels in blood samples obtained from neonates born to SARS-CoV-2-positive mothers. However, peripartum exposure to maternal SARS-CoV-2 did not appear to disrupt the hemostatic profile of the exposed newborns based on ROTEM test results.

Temporal transcriptional profiling of host cells infected by a veterinary alphaherpesvirus using nanopore sequencing

In our research, we performed temporal transcriptomic profiling of host cells infected with Equid alphaherpesvirus 1 (EHV-1) by utilizing direct cDNA sequencing based on nanopore MinION technology. The sequencing reads were harnessed for transcript quantification at various time points. Viral infection-induced differential gene expression was identified through the edgeR package. The identified genes were segmented into six groups based on their kinetic characteristics. The initial three clusters encompass immediate-early response genes, typically transcription factors and elements of antiviral signaling pathways. These genes were either upregulated (cluster 1) or downregulated (clusters 2 and 3) during the early infection phase. The remaining three clusters include late response genes. In these categories, it is challenging to determine whether changes in gene expression are directly connected to the viral infection or merely side effects of the infection. A study of gene associations using the STRINGDB software revealed several gene networks that might be directly impacted by the virus. We also explored whether gene co-expression could be a result of their collective regulation by upstream transcription factors using the Gene Regulatory Network database. Finally, our differential transcript usage (DTU) analysis identified a number of genes that exhibited altered proportions of transcript isoforms in comparison to non-infected cells. Thus, our analysis revealed that EHV-1 infection not only alters host gene expression but also leads to differential use of transcript isoforms, particularly splice variants.

The Therapeutic Efficacy and Molecular Mechanisms of Artemisia argyi Essential Oil in Treating Feline Herpesvirus Infection via Nasal Drops

This study aimed to explore the therapeutic potential and mechanisms of Artemisia argyi essential oil (AAEO) in managing feline herpesvirus type 1 (FeHV-1) infections. FeHV-1, the causative agent of feline viral rhinotracheitis (FVR), leads to severe respiratory and systemic complications in cats. In this study, 35 cats were divided into blank, FeHV-1 infection, and AAEO treatment groups (high, medium, and low doses). In vivo experiments demonstrated that AAEO alleviated clinical symptoms, reduced tissue damage, and modulated immune responses. The AAEO-treated groups showed higher survival rates, stabilized body temperatures, and less severe weight loss compared to the FeHV-1 group. Histopathological analysis revealed improved integrity in nasal, tracheal, and bronchial tissues. Transcriptomic and proteomic analyses identified critical pathways, such as IL-17 signaling, influenced by AAEO treatment, highlighting its role in suppressing inflammation and protecting tissue integrity. In vitro assays revealed that AAEO has concentration-dependent cytotoxicity in feline kidney cells (F81) and provides protective effects when used as a pre-treatment. These findings suggest that AAEO enhances host immune defenses and mitigates FeHV-1-induced damage through immune modulation and tissue protection.

Interferon-Stimulated Genes and Immune Metabolites as Broad-Spectrum Biomarkers for Viral Infections

The type I interferon (IFN-I) response is a critical component of the immune defense against various viral pathogens, triggering the expression of hundreds of interferon-stimulated genes (ISGs). These ISGs encode proteins with diverse antiviral functions, targeting various stages of viral replication and restricting infection spread. Beyond their antiviral functions, ISGs and associated immune metabolites have emerged as promising broad-spectrum biomarkers that can differentiate viral infections from other conditions. This review provides an overview of the diagnostic potential of ISGs at transcript and protein levels, as well as their immune metabolites. We focus on their clinical applications and the sensitivity and specificity of these biomarkers through receiver operating characteristic (ROC) analysis. We highlight the need for further research to facilitate the effective translation of these biomarkers into clinical practice.

Serum proteomics identifies biomarkers for predicting non-survivors in elderly COVID-19 patients

In December 2022, China ceased the zero-COVID-19 policy, resulting in an increase in hospitalizations and deaths due to COVID-19, particularly among the elderly population. Predicting non-survivors aims to identify high-risk patients and enable targeted interventions to improve survival rates. Additionally, understanding factors affecting prognosis provides essential insights for further research and optimization of treatment strategies. We applied 4D-DIA mass spectrometry for serum proteome analysis and provided a comprehensive characterization of disease features in elderly patients within the Chinese population. Our study elucidated that immune disorders, lung damage, and cardiovascular disorders are predominant causes of death in these patients. Compared to clinical indices, proteomic analysis is more sensitive in tracing these disorders. We also provided a prediction panel for survival outcomes of elderly patients using levels of CXCL10, CXCL16 and IL1RA, which were validated by ELISA. These biomarkers will help improve predictive efficacy for survival outcomes in elderly patients.

Inflammaging Markers in the Extremely Cold Climate: A Case Study of Yakutian Population

Yakutia is one of the coldest permanently inhabited regions in the world, characterized by a subarctic climate with average January temperatures near -40 °C and the minimum below -60 °C. Recently, we demonstrated accelerated epigenetic aging of the Yakutian population in comparison to their Central Russian counterparts, residing in a considerably milder climate. In this paper, we analyzed these cohorts from the inflammaging perspective and addressed two hypotheses: a mismatch in the immunological profiles and accelerated inflammatory aging in Yakuts. We found that the levels of 17 cytokines displayed statistically significant differences in the mean values between the groups (with minimal p-value = 2.06 × 10-19), and 6 of them are among 10 SImAge markers. We demonstrated that five out of these six markers (PDGFB, CD40LG, VEGFA, PDGFA, and CXCL10) had higher mean levels in the Yakutian cohort, and therefore, due to their positive chronological age correlation, might indicate a trend toward accelerated inflammatory aging. At the same time, a statistically significant biological age acceleration difference between the two cohorts according to the inflammatory SImAge clock was not detected because they had similar levels of CXCL9, CCL22, and IL6, the top contributing biomarkers to SImAge. We introduced an explainable deep neural network to separate individual inflammatory profiles between the two groups, resulting in over 95% accuracy. The obtained results allow for hypothesizing the specificity of cytokine and chemokine profiles among people living in extremely cold climates, possibly reflecting the effects of long-term human (dis)adaptation to cold conditions related to inflammaging and the risk of developing a number of pathologies.

Recent Advances in Immunological Landscape and Immunotherapeutic Agent of Nipah Virus Infection

Over the last two decades, the Nipah virus (NiV) emerged as a highly lethal zoonotic pathogen to humans. Outbreaks occurred occasionally in South and Southeast Asia. Therefore, a safe and effective vaccine against the virus is needed to fight against the deadly virus. Understanding the immunological landscape during this lethal virus infection is necessary in this direction. However, we found scattered information on the immunological landscape of the virus's reservoir, as well as hosts such as humans and livestock. The review provides a recent understanding of the immunological landscape of the virus's reservoir, human hosts, monoclonal antibodies, and vaccines for NiV infection. To describe the immunological landscape, we divided our review article into some points. Firstly, we illustrated bats' immune response as a reservoir during the NiV infection. Secondly, we illustrated an overview of the molecular mechanisms underlying the immune response to the NiV infection, various immune cells, humans' innate immune response, adaptive immunity, and the landscape of cytokines and chemokines. We also discussed INF escape, NET evasion, the T cell landscape, and the B cell landscape during virus infection. Thirdly, we also demonstrated the potential monoclonal antibody therapeutics, and vaccines. Finally, neutralizing antibodies (nAbs) of NiV and potentially other therapeutic strategies were discussed. The review will help researchers for better understanding the immunological landscape, mAbs, and vaccines, enabling them to develop their next-generation versions.

BK Polyomavirus Infection in Kidney Transplantation: A Comprehensive Review of Current Challenges and Future Directions

BK polyomavirus (BKPyV) infection of the kidney graft remains a major clinical issue in the field of organ transplantation. Risk factors for BKPyV-associated nephropathy (BKPyVAN) and molecular tools for determining viral DNA loads are now better defined. BKPyV DNAemia in plasma, in particular, plays a central role in diagnosing active infection and managing treatment decisions. However, significant gaps remain in the development of reliable biomarkers that can anticipate BKPyV viremia and predict disease outcomes. Biomarkers under active investigation include urine-based viral load assays, viral antigen detection, and immune responses against BKPyV, which may offer more precise methods for monitoring disease progression. In addition, treatment of BKPyVAN is currently based on immunosuppression minimization, while the role of adjunctive therapies remains an area of active research, highlighting the need for more personalized treatment regimens. Ongoing clinical trials are also exploring the efficacy of T-cell-based immunotherapies. The clinical management of BKPyV infection, based on proactive virological monitoring, immune response assessment, integrated histopathology, and timely immunosuppression reduction, is likely to reduce the burden of disease and improve outcomes in kidney transplantation.

Defective proviruses significantly impact viral transcription and immune activation in men and women with HIV-1 subtype C in rural South Africa

Introduction

The main obstacle to achieving an HIV-1 cure is the proviral reservoir. To promote equity in HIV cure strategies, it is crucial to study the viral reservoir of the predominant HIV-1 subtype C in both women and men. Therefore, we investigated the dynamics of the (intact) viral reservoir in relation to plasma viral load (VL), CD4+ T cell count, and immune activation before and during 96 weeks of successful antiretroviral therapy (ART).

Methods

Eighty-two participants (62% female) newly initiating ART in a rural clinic in South Africa were included in the study. Blood samples were collected at baseline, week 48, and week 96, and CD4 count was determined. Plasma was used for VL and immune marker analyses, while isolated peripheral blood mononuclear cells (PBMCs) were used for the quantification of cellular multiple spliced HIV-1 RNA (msRNA) and the intact proviral DNA assay. For the longitudinal analyses on ART, we selected only those participants who durably suppressed their VL to <200 copies/mL during 48 (n=65) and/or 96 (n=60) weeks of treatment.

Results

At ART initiation, the median CD4 count was 234 cells/mm3 and VL was 68,897 copies/mL. Interestingly, at baseline the number of defective proviruses was significantly correlated with VL (p<0.0001), msRNA (p<0.0001), CD4 count (p=0.0008), CXCL10 (p=0.0003) and TNF-α (p=0.0394). During successful ART, a significant decrease of both the intact and defective proviral reservoir was observed (p<0.0001). The decrease of the intact proviral reservoir was more profound compared to the defective fraction after 96 weeks of therapy. In addition, a significant decrease in cellular msRNA and IL-6, IL-7, TNF-α, sCD14, sCD163, CCL2, CXCL10, and CRP was detected.

Discussion

This study underscores the significant relationship observed prior to therapy initiation between the number of defective proviruses, viral transcription/production and their association with immune response indicators such as CD4 count, CXCL10, and TNF-α. Furthermore, the observation of a less pronounced decrease of the defective proviral DNA highlights the importance of addressing both intact and defective proviruses in therapeutic strategies to enhance clinical outcomes for people with HIV-1. Together, these findings suggest a significant role of the defective proviruses in HIV-related disease progression.

A Lassa virus live attenuated vaccine candidate that is safe and efficacious in guinea pigs

Lassa virus (LASV) is a rodent-borne mammarenavirus that causes tens to hundreds of thousands of human infections annually in Western Africa. Approximately 20% of these infections progress to Lassa fever (LF), an acute disease with case-fatality rates from ≈20-70%. Currently, there are no approved vaccines or specific therapeutics to prevent or treat LF. The LASV genome consists of a small (S) segment that has two genes, GP and NP, and a large (L) segment that has two genes, L and Z. In both segments, the two genes are separated by non-coding intergenic regions (IGRs). Recombinant LASVs (rLASVs), in which the L segment IGR was replaced with the S segment IGR or in which the GP gene was codon-deoptimized, lost fitness in vitro, were highly attenuated in vivo, and, when used as vaccines, protected domesticated guinea pigs from otherwise lethal LASV exposure. Here, we report the generation of rLASV/IGR-CD, which includes both determinants of attenuation and further enhances the safety of the vaccine compared with its predecessors. rLASV/IGR-CD grew to high titers in Vero cells, which are approved for human vaccine production, but did not cause signs of disease or pathology in guinea pigs. Importantly, guinea pigs vaccinated with rLASV/IGR-CD were completely protected from disease and death after a typically lethal exposure to wild-type LASV. Our data support the development of rLASV/IGR-CD as a live-attenuated LF vaccine with stringent safety features.

Euphorbium compositum SN improves the innate defenses of the airway mucosal barrier network during rhinovirus infection

BACKGROUND

Rhinoviruses (RV) are the major cause of common colds in healthy individuals and are associated with acute exacerbations in patients with chronic lung diseases. Yet, no vaccines or effective treatment against RV are available. This study investigated the effect of Euphorbium compositum SN (ECSN6), a multicomponent, multitarget medication made from natural ingredients, on the mucosal barrier network during RV infection.

METHODS

Mucociliary-differentiated airway epithelial cell cultures were infected with RV or sham, and treated with 20% ECSN6 or placebo twice daily. Barrier integrity was assessed by measuring transepithelial resistance (TER), permeability to inulin, and expression and localization of intercellular junctions proteins (IJ). Ciliary beat frequency (CBF), expression of pro-inflammatory cytokines, antiviral interferons and mucins, and viral load were also measured. C57BL/6 mice were infected intranasally with RV or sham and treated with 40% ECSN6 or placebo twice daily. Inflammation of sinunasal mucosa, localization of E-cadherin, viral load and mucin gene expression were determined.

RESULTS

ECSN6-treated, uninfected cell cultures showed small, but significant increase in TER over placebo, which was associated with enhanced localization of E-cadherin and ZO-1 to IJ. In RV-infected cultures, treatment with ECSN6, but not placebo prevented RV-induced (1) reduction in TER, (2) dissociation of E-cadherin and ZO-1 from the IJ, (3) mucin expression, and (4) CBF attenuation. ECSN6 also decreased RV-stimulated expression of pro-inflammatory cytokines and permeability to inulin. Although ECSN6 significantly increased the expression of some antiviral type I and type III interferons, it did not alter viral load. In vivo, ECSN6 reduced RV-A1-induced moderate inflammation of nasal mucosa, beneficially affected RV-A1-induced cytokine responses and Muc5ac mRNA expression and prevented RV-caused dissociation of E-cadherin from the IJ of nasal mucosa without an effect on viral clearance.

CONCLUSIONS

ECSN6 prevents RV-induced airway mucosal barrier dysfunction and improves the immunological and mucociliary barrier function. ECSN6 may maintain integrity of barrier function by promoting localization of tight and adherence junction proteins to the IJ. This in turn may lead to the observed decrease in RV-induced pro-inflammatory responses in vitro. By improving the innate defenses of the airway mucosal barrier network, ECSN6 may alleviate respiratory symptoms caused by RV infections.

Effects of Phenolic Acids Produced from Food-Derived Flavonoids and Amino Acids by the Gut Microbiota on Health and Disease

The gut microbiota metabolizes flavonoids, amino acids, dietary fiber, and other components of foods to produce a variety of gut microbiota-derived metabolites. Flavonoids are the largest group of polyphenols, and approximately 7000 flavonoids have been identified. A variety of phenolic acids are produced from flavonoids and amino acids through metabolic processes by the gut microbiota. Furthermore, these phenolic acids are easily absorbed. Phenolic acids generally represent phenolic compounds with one carboxylic acid group. Gut microbiota-derived phenolic acids have antiviral effects against several viruses, such as SARS-CoV-2 and influenza. Furthermore, phenolic acids influence the immune system by inhibiting the secretion of proinflammatory cytokines, such as interleukin-1β and tumor necrosis factor-α. In the nervous systems, phenolic acids may have protective effects against neurodegenerative diseases, such as Alzheimer's and Parkinson's diseases. Moreover, phenolic acids can improve levels of blood glucose, cholesterols, and triglycerides. Phenolic acids also improve cardiovascular functions, such as blood pressure and atherosclerotic lesions. This review focuses on the current knowledge of the effects of phenolic acids produced from food-derived flavonoids and amino acids by the gut microbiota on health and disease.

Cxcl10 is required for survival during SARS-CoV-2 infection in mice

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiological agent of the coronavirus disease 2019 (COVID-19) pandemic, remains endemic worldwide ~5 years since the first documented case. Severe COVID-19 is widely considered to be caused by a dysregulated immune response to SARS-CoV-2 within the respiratory tract. Circulating levels of the chemokine CXCL10 are strongly positively associated with poor outcome; however, its precise role in pathogenesis and its suitability as a therapeutic target have remained undefined. Here, we challenged 4-6 month old C57BL/6 mice genetically deficient in Cxcl10 with a mouse-adapted strain of SARS-CoV-2. Infected male, but not female, Cxcl10 -/- mice displayed increased mortality compared to wild type controls. Histopathological damage, inflammatory gene induction and virus load in the lungs of male mice 4 days post infection and before death were not broadly influenced by Cxcl10 deficiency. However, accumulation of B cells and both CD4+ and CD8+ T cells in the lung parenchyma of infected mice was reduced in the absence of Cxcl10. Thus, during acute SARS-CoV-2 infection, Cxcl10 regulates lymphocyte infiltration in the lung and confers protection against mortality. Our preclinical model results do not support targeting CXCL10 therapeutically in severe COVID-19.

Whole-transcriptome analyses of ovine lung microvascular endothelial cells infected with bluetongue virus

Bluetongue virus (BTV) infection induces profound and intricate changes in the transcriptional profile of the host to facilitate its survival and replication. However, there have been no whole-transcriptome studies on ovine lung microvascular endothelial cells (OLMECs) infected with BTV. In this study, we comprehensively analysed the whole-transcriptome sequences of BTV-1 serotype-infected and mock-infected OLMECs and subsequently performed bioinformatics differential analysis. Our analysis revealed 1215 differentially expressed mRNA transcripts, 82 differentially expressed long noncoding RNAs (lncRNAs) transcripts, 63 differentially expressed microRNAs (miRNAs) transcripts, and 42 differentially expressed circular RNAs (circRNAs) transcripts. Annotation from Gene Ontology, enrichment from the Kyoto Encyclopedia of Genes and Genomes, and construction of endogenous competing RNA network analysis revealed that the differentially expressed RNAs primarily participated in viral sensing and signal transduction pathways, antiviral and immune responses, inflammation, and extracellular matrix (ECM)-related pathways. Furthermore, protein‒protein interaction network analysis revealed that BTV may regulate the conformation of ECM receptor proteins and change their biological activity through a series of complex mechanisms. Finally, on the basis of real-time fluorescence quantitative polymerase chain reaction results, the expression trends of the differentially expressed RNA were consistent with the whole-transcriptome sequencing data, such as downregulation of the expression of COL4A1, ITGA8, ITGB5, and TNC and upregulation of the expression of CXCL10, RNASEL, IRF3, IRF7, and IFIHI. This study provides a novel perspective for further investigations of the mechanism of the ECM in the BTV-host interactome and the pathogenesis of lung microvascular endothelial cells.

Interferon-stimulated gene 56 positively regulates Toll-like receptor 3-mediated CXCL10 expression in human renal proximal tubular epithelial cells

Viral infections in tubular epithelial cells lead to the production of inflammatory cytokines by innate immunity, causing tubulointerstitial nephritis. TLR3 recognizes viral infections and acts via the activation of interferon (IFN)/IFN-stimulated genes (ISGs). This study investigates the role of ISG56, a representative ISG, in TLR3 signaling in cultured human renal proximal tubular epithelial cells (hRPTECs). To this end, hRPTECs were stimulated by a synthetic TLR3 ligand, polyinosinic-polycytidylic acid (poly IC), recombinant human interferon-β [r(h)IFN-β] or Japanese encephalitis virus (JEV) infection and assayed for inflammatory cytokine mRNA expression by RT-qPCR, and protein expression via western blotting or ELISA. ISG56 was expressed by poly IC or r(h)IFN-β and IFN-β knockdown reduced poly IC-induced expression of ISG56 and CXCL10. Moreover, ISG56 knockdown reduced poly IC- or r(h)IFN-β-induced expression of CXCL10 at the same time as increasing JEV growth and reducing CXCL10 expression induced by JEV infection. Overall, TLR3 signaling induced IFN-β-dependent expression of ISG56 and CXCL10. We show that ISG56 possibly plays a critical role in antiviral immunity of hRPTECs by positive regulation of IFN-β-mediated CXCL10 expression downstream of TLR3.

Gene expression in heart, kidney, and liver identifies possible mechanisms underpinning fetal resistance and susceptibility to in utero PRRSV infection

Porcine reproductive and respiratory syndrome (PRRS) is one of the costliest diseases to pork producers worldwide. We tested samples from the pregnant gilt model (PGM) to better understand the fetal response to in-utero PRRS virus (PRRSV) infection. Our goal was to identify critical tissues and genes associated with fetal resilience or susceptibility. Pregnant gilts (N=22) were infected with PRRSV on day 86 of gestation. At 21 days post maternal infection, the gilts and fetuses were euthanized, and fetal tissues collected. Fetuses were characterized for PRRS viral load in fetal serum and thymus, and preservation status (viable or meconium stained: VIA or MEC). Fetuses (N=10 per group) were compared: uninfected (UNIF; <1 log/µL PRRSV RNA), resilient (HV_VIA, >5 log virus/µL but viable), and susceptible (HV_MEC, >5 log virus/µL with MEC). Gene expression in fetal heart, kidney, and liver was investigated using NanoString transcriptomics. Gene categories investigated were hypothesized to be involved in fetal response to PRRSV infection: renin- angiotensin-aldosterone, inflammatory, transporter and metabolic systems. Following PRRSV infection, CCL5 increased expression in heart and kidney, and ACE2 decreased expression in kidney, each associated with fetal PRRS susceptibility. Liver revealed the most significant differential gene expression: CXCL10 decreased and IL10 increased indicative of immune suppression. Increased liver gene expression indicated potential associations with fetal PRRS susceptibility on several systems including blood pressure regulation (AGTR1), energy metabolism (SLC16A1 and SLC16A7), tissue specific responses (KL) and growth modulation (TGFB1). Overall, analyses of non-lymphoid tissues provided clues to mechanisms of fetal compromise following maternal PRRSV infection.

An LGR6 frameshift variant abrogates receptor expression on select leukocyte subsets and is associated with viral infections

ABSTRACT

The leucine-rich repeat-containing G-protein-coupled receptor 6 (LGR6) was recently identified as the cognate receptor for the proresolving mediator maresin 1 (MaR1). To address the biological role of LGR6 in humans, we investigated the functional impact of a genetic variant in the gene encoding for LGR6, which is predicted to lead to a frameshift mutation in one of the receptor isoforms, on both receptor expression and immune cell responses. In neutrophils, monocytes, and natural killer (NK) cells from volunteers homozygous for this variant, we found a significant downregulation in the expression of LGR6 when compared with controls without the variant; whereas the LGR6 expression was essentially similar in monocyte-derived macrophages and CD8+ T cells. Functionally, loss of LGR6 expression was linked with a decreased ability of neutrophils and monocytes to phagocytose bacteria. We observed an increase in neutrophil chemotaxis and leukotriene B4 production and increased expression of activation markers, including markers for platelet-leukocyte phagocyte heterotypic aggregates, such as CD41, in neutrophils and monocytes from the variant group. Using data from the UK Biobank, we found that at a population level the rs4266947 variant, which is in high linkage disequilibrium with rs74355478, was associated with a higher incidence of viral infections. Intriguingly, neutrophils, NK cells, and CD8+ T cells from volunteers with the LGR6 variant displayed altered viral responses when stimulated with Toll-like receptor 3 (TLR3), TLR7/TLR8, and TLR9 agonists. Together, these findings shed new light on the cell type-specific regulation of LGR6 expression and the role of this receptor in directing host immune responses.

Age-related dysregulation of CXCL9/10 in monocytes is linked to impaired innate immune responses in a mouse model of Staphylococcus aureus osteomyelitis

BACKGROUND

Age-associated impairments in innate immunity are believed to be a causative factor responsible for severe pathogenesis of Staphylococcus aureus (S. aureus) infection in the bone tissue. However, the basis for age-associated decline in innate immune response upon S. aureus infection remains poorly understood.

RESULTS

Our transcriptional data (GEO: GSE166522) from a mouse model of S. aureus osteomyelitis show up-regulated CXCL9 and CXCL10 (CXCL9/10), which is further confirmed in vitro and in vivo by the present study. Notably, monocytes are a main source for CXCL9/10 production in bone marrow upon S. aureus challenge, but this response declines in middle-aged mice. Interestingly, conditional medium of bone marrow monocytes from middle-aged mice has a strikingly decreased effect on bactericidal functions of neutrophils and macrophages compares with that from young mice. We further show that activation of CXCL9/10-CXCR3 axis between monocytes and macrophages/neutrophils promotes the bactericidal function of the cells, whereas blocking the axis impairs such function. Importantly, treatment with either exogenous CXCL9 or CXCL10 in a middle-aged mice model enhances, while pharmacological inhibition of CXCR3 in young mice model impairs, bacterial clearance and bone marrow structure.

CONCLUSIONS

These findings demonstrate that bone marrow monocytes act as a critical promotor of innate immune response via the CXLCL9/10-CXCR3 axis upon S. aureus infection, and that the increased susceptibility to S. aureus infection in skeleton in an aged host may be largely attributable to the declined induction of CXCR9/10 in monocytes.

TLR4/7-mediated host-defense responses of gingival epithelial cells

Gingival epithelial cells (GECs) are physical and immunological barriers against outward pathogens while coping with a plethora of non-pathogenic commensal bacteria. GECs express several members of Toll-like receptors (TLRs) and control subsequent innate immune responses. TLR4 senses lipopolysaccharide (LPS) while TLR7/8 recognizes single-strand RNA (ssRNA) playing important roles against viral infection. However, their distinct roles in GECs have not been fully demonstrated. Here, we analyzed biological responses of GECs to  LPS and CL075, a TLR7/8 agonist. GE1, a mouse gingival epithelial cell line, constitutively express TLR4 and TLR7, but not TLR8, like primary skin keratinocytes. Stimulation of GE1 cells with CL075 induced cytokine, chemokine, and antimicrobial peptide  expressions, the pattern of which is rather different from that with LPS: higher mRNA levels of interferon (IFN) β, CXCL10, and β-defensin (BD) 14 (mouse homolog of human BD3); lower levels of tumor necrosis factor (TNF), CCL5, CCL11, CCL20, CXCL2, and CX3CL1. As for the intracellular signal transduction of GE1 cells, CL075 rapidly induced significant AKT phosphorylation but failed to activate IKKα/β-NFκB pathway, whereas LPS induced marked IKKα/β-NFκB activation without significant AKT phosphorylation. In contrast, both CL075 and LPS induced rapid IKKα/β-NFκB activation and AKT phosphorylation in a macrophage cell line. Furthermore, specific inhibition of AKT activity abrogated CL075-induced IFNβ, CXCL10, and BD14 mRNA expression in GE1 cells. Thus, TLR4/7 ligands appear to induce rather different host-defense responses of GECs through distinct intracellular signaling mechanisms.

Neonatal Chlamydia muridarum respiratory infection causes neuroinflammation within the brainstem during the early postnatal period

Respiratory infections are one of the most common causes of illness and morbidity in neonates worldwide. In the acute phase infections are known to cause wide-spread peripheral inflammation. However, the inflammatory consequences to the critical neural control centres for respiration have not been explored. Utilising a well characterised model of neonatal respiratory infection, we investigated acute responses within the medulla oblongata which contains key respiratory regions. Neonatal mice were intranasally inoculated within 24 h of birth, with either Chlamydia muridarum or sham-infected, and tissue collected on postnatal day 15, the peak of peripheral inflammation. A key finding of this study is that, while the periphery appeared to show no sex-specific effects of a neonatal respiratory infection, sex had a significant impact on the inflammatory response of the medulla oblongata. There was a distinct sex-specific response in the medulla coincident with peak of peripheral inflammation, with females demonstrating an upregulation of anti-inflammatory cytokines and males showing very few changes. Microglia also demonstrated sex-specificity with the morphology of females and males differing based upon the nuclei. Astrocytes showed limited changes during the acute response to neonatal infection. These data highlight the strong sex-specific impact of a respiratory infection can have on the medulla in the acute inflammatory phase.

Transcriptome Analysis in Air-Liquid Interface Porcine Respiratory Epithelial Cell Cultures Reveals That the Betacoronavirus Porcine Encephalomyelitis Hemagglutinating Virus Induces a Robust Interferon Response to Infection

Porcine hemagglutinating encephalomyelitis virus (PHEV) replicates in the upper respiratory tract and tonsils of pigs. Using an air-liquid interface porcine respiratory epithelial cells (ALI-PRECs) culture system, we demonstrated that PHEV disrupts respiratory epithelia homeostasis by impairing ciliary function and inducing antiviral, pro-inflammatory cytokine, and chemokine responses. This study explores the mechanisms driving early innate immune responses during PHEV infection through host transcriptome analysis. Total RNA was collected from ALI-PRECs at 24, 36, and 48 h post inoculation (hpi). RNA-seq analysis was performed using an Illumina Hiseq 600 to generate 100 bp paired-end reads. Differential gene expression was analyzed using DeSeq2. PHEV replicated actively in ALI-PRECs, causing cytopathic changes and progressive mucociliary disruption. Transcriptome analysis revealed downregulation of cilia-associated genes such as CILK1, DNAH11, LRRC-23, -49, and -51, and acidic sialomucin CD164L2. PHEV also activated antiviral signaling pathways, significantly increasing the expression of interferon-stimulated genes (RSAD2, MX1, IFIT, and ISG15) and chemokine genes (CCL5 and CXCL10), highlighting inflammatory regulation. This study contributes to elucidating the molecular mechanisms of the innate immune response to PHEV infection of the airway epithelium, emphasizing the critical roles of the mucociliary, interferon, and chemokine responses.

The glycosaminoglycan-binding chemokine fragment CXCL9(74-103) reduces inflammation and tissue damage in mouse models of coronavirus infection

Introduction

Pulmonary diseases represent a significant burden to patients and the healthcare system and are one of the leading causes of mortality worldwide. Particularly, the COVID-19 pandemic has had a profound global impact, affecting public health, economies, and daily life. While the peak of the crisis has subsided, the global number of reported COVID-19 cases remains significantly high, according to medical agencies around the world. Furthermore, despite the success of vaccines in reducing the number of deaths caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), there remains a gap in the treatment of the disease, especially in addressing uncontrolled inflammation. The massive recruitment of leukocytes to lung tissue and alveoli is a hallmark factor in COVID-19, being essential for effectively responding to the pulmonary insult but also linked to inflammation and lung damage. In this context, mice models are a crucial tool, offering valuable insights into both the pathogenesis of the disease and potential therapeutic approaches.

Methods

Here, we investigated the anti-inflammatory effect of the glycosaminoglycan (GAG)-binding chemokine fragment CXCL9(74-103), a molecule that potentially decreases neutrophil transmigration by competing with chemokines for GAG-binding sites, in two models of pneumonia caused by coronavirus infection.

Results

In a murine model of betacoronavirus MHV-3 infection, the treatment with CXCL9(74-103) decreased the accumulation of total leukocytes, mainly neutrophils, to the alveolar space and improved several parameters of lung dysfunction 3 days after infection. Additionally, this treatment also reduced the lung damage. In the SARS-CoV-2 model in K18-hACE2-mice, CXCL9(74-103) significantly improved the clinical manifestations of the disease, reducing pulmonary damage and decreasing viral titers in the lungs.

Discussion

These findings indicate that CXCL9(74-103) resulted in highly favorable outcomes in controlling pneumonia caused by coronavirus, as it effectively diminishes the clinical consequences of the infections and reduces both local and systemic inflammation.

Follow-up of cognitive impairment and inflammatory profile in individuals with mild COVID-19

Individuals who experience mild COVID-19 can suffer from long-lasting cognitive symptoms. Notably, 26% of these individuals experience difficulties with visuospatial abilities six months after infection. However, among those who initially exhibited visuoconstructive impairments, 66% showed improvement or complete reversal over time. Additionally, changes in cytokine levels, particularly CCL11, HGF, and CXCL10, were observed. These results suggest a potential link between ongoing cognitive issues and elevated levels of pro-inflammatory cytokines, which merits further investigation.

Large-Scale Proteome Profiling Identifies Biomarkers Associated with Suspected Neurosyphilis Diagnosis

Neurosyphilis (NS) is a central nervous system (CNS) infection caused by Treponema pallidum (T. pallidum). NS can occur at any stage of syphilis and manifests as a broad spectrum of clinical symptoms. Often referred to as "the great imitator," NS can be easily overlooked or misdiagnosed due to the absence of standard diagnostic tests, potentially leading to severe and irreversible organ dysfunction. In this study, proteomic and machine learning model techniques are used to characterize 223 cerebrospinal fluid (CSF) samples to identify diagnostic markers of NS and provide insights into the underlying mechanisms of the associated inflammatory responses. Three biomarkers (SEMA7A, SERPINA3, and ITIH4) are validated as contributors to NS diagnosis through multicenter verification of an additional 115 CSF samples. We anticipate that the identified biomarkers will become effective tools for assisting in diagnosis of NS. Our insights into NS pathogenesis in brain tissue may inform therapeutic strategies and drug discoveries for NS patients.

Disease-specific plasma protein profiles in patients with fever after traveling to tropical areas

Fever is common among individuals seeking healthcare after traveling to tropical regions. Despite the association with potentially severe disease, the etiology is often not determined. Plasma protein patterns can be informative to understand the host response to infection and can potentially indicate the pathogen causing the disease. In this study, we measured 49 proteins in the plasma of 124 patients with fever after travel to tropical or subtropical regions. The patients had confirmed diagnoses of either malaria, dengue fever, influenza, bacterial respiratory tract infection, or bacterial gastroenteritis, representing the most common etiologies. We used multivariate and machine learning methods to identify combinations of proteins that contributed to distinguishing infected patients from healthy controls, and each other. Malaria displayed the most unique protein signature, indicating a strong immunoregulatory response with high levels of IL10, sTNFRI and II, and sCD25 but low levels of sCD40L. In contrast, bacterial gastroenteritis had high levels of sCD40L, APRIL, and IFN-γ, while dengue was the only infection with elevated IFN-α2. These results suggest that characterization of the inflammatory profile of individuals with fever can help to identify disease-specific host responses, which in turn can be used to guide future research on diagnostic strategies and therapeutic interventions.

Studying the correlation of inflammatory cytokines to COVID-19 disease

Extreme response of the immune system develops cytokine storm which might be crucial in the pathology of COVID-19. The research aims to evaluate the serum level of IL-6, TNF-α, and IP-10 in severe, mild, and pre-vaccinated one-dose COVID-19 patients and investigate their clinical value and effect in the disease development among different groups of patients. A total of 72 samples were collected 18 as healthy control and 54 from confirmed COVID-19 patients including 18 mild, 18 severe, and 18 pre-vaccinated (one dose). It was confirmed that the severe group of COVID-19 patients had the highest circulating IL-6, TNF- α, and IP-10. IL-6 level in mild and pre-vaccinated (one dose) was significantly lower than in severe. In conclusion, IL-6, TNF-α, and IP-10 are associated with the pathogenicity of COVID-19, furthermore, vaccination could help to control severity of the disease.

Production and characterization of anti-porcine CXCL10 monoclonal antibodies

Research on C-X-C motif chemokine ligand 10 (CXCL10) has been widely reported for humans and select animal species, yet immune reagents are limited for pig chemokines. Our goal is to provide veterinary immunologists and the biomedical community with new commercial immune reagents and standardized assays. Recombinant porcine CXCL10 (rPoCXCL10) protein was produced by yeast expression and used to generate a panel of α CXCL10 monoclonal antibodies (mAbs). All mAbs were assessed for cross-inhibition and reactivity to orthologous yeast expressed CXCL10 proteins. Characterization of a panel of nine α PoCXCL10 mAbs identified six distinct antigenic determinants. A sensitive quantitative sandwich ELISA was developed with anti-PoCXCL10-1.6 and -1.9 mAb; reactivity was verified with both rPoCXCL10 and native PoCXCL10, detected in supernatants of peripheral blood mononuclear cells stimulated with rPoIFNγ or PMA/Ionomycin. Immunostaining of in vitro rPoIFNγ stimulated pig spleen and blood cells verified CXCL10 + cells as CD3-CD4-CD172+, with occasional CD3-CD4 + CD172 + subsets. Comparison studies determined that α PoCXCL10-1.4 mAb was the ideal mAb clone for intracellular staining, whereas with α PoCXCL10-1.1 and -1.2 mAbs were best for immunohistochemistry analyses. These techniques and tools will be useful for evaluating swine immune development, responses to infectious diseases and vaccines, as well as for improving utility of pigs as an important biomedical model.

Microbiota and glioma: a new perspective from association to clinical translation

Gliomas pose a significant challenge in oncology due to their malignant nature, aggressive growth, frequent recurrence, and complications posed by the blood-brain barrier. Emerging research has revealed the critical role of gut microbiota in influencing health and disease, indicating its possible impact on glioma pathogenesis and treatment responsiveness. This review focused on existing evidence and hypotheses on the relationship between microbiota and glioma from progression to invasion. By discussing possible mechanisms through which microbiota may affect glioma biology, this paper offers new avenues for targeted therapies and precision medicine in oncology.

Cell-Specific Regulation of Inflammatory Cytokines and Acute-Phase Proteins by the Glucocorticoid Receptor

BACKGROUND

Literature and data mining found abnormal induction of chemokine (C-X-C motif) ligand 1 (CXCL1) and CXCL8 and down-regulation of CXCL2 in inflammatory liver diseases. This study was performed to understand the glucocorticoid receptor's (GR's) effects on chemokine and acute-phase protein expression in human liver, in settings of bacterial infection (modeled using LPS) or inflammation (modeled using TNFα).

METHODS

Primary human hepatocytes (PHH) were treated with combinations of tumor necrosis factor alpha (TNFα), lipopolysaccharide (LPS), and dexamethasone (DEX) for 24 h, following which chemokine mRNA and protein expression were analyzed using qPCR and enzyme-linked immunosorbent assay assays. Dual luciferase assays were performed on transfected cell lines. Mutant CXCL2 promoters were used in dual luciferase assays to identify specific regions of the CXCL2 promoter affected by GR, TNFα, or hepatocyte nuclear factor 4α (HNF4α, a liver-enriched transcription factor).

RESULTS

In PHH from donor 1, GR strongly inhibited LPS-induced CXCL1 and CXCL8 translation and transcription, whereas CXCL2 transcription tended to increase with DEX treatment. In PHH from donor 2, DEX treatment inhibited protein expression and secretion of CXCL1 and CXCL8 induced by TNFα and/or LPS, whereas CXCL2 upregulation was largely unaffected by DEX treatment. In nonliver HEK293T cells GR activity inhibited CXCL2 promoter activity. However, in liver-derived HEPG2 cells, GR induced CXCL2 promoter activity. A 407-base pair region upstream of CXCL2 promoter is necessary for full GR functionality in HEPG2 cells. TNFα synergized with HNF4α in inducing CXCL2 promoter activity in HEPG2 cells.

CONCLUSIONS

GR's effects on chemokine expression are cell-type specific and chemokine specific. GR down-regulated CXCL1 and CXCL8 in different cell types, whereas the specific activation of CXCL2 in hepatocytes and down-regulation of CXCL2 in nonhepatocytes by GR appears due to cell-specific utilization of CXCL2 promoter. By specifically increasing GR activity in the liver, we may normalize chemokine imbalances and prevent sepsis in inflammatory liver diseases.

Identification of interferon-stimulated genes with modulated expression during hepatitis E virus infection in pig liver tissues and human HepaRG cells

Introduction

Hepatitis E virus (HEV) is a common cause of enterically transmitted acute hepatitis worldwide. The virus is transmitted by the fecal-oral route via the consumption of contaminated water supplies and is also a zoonotic foodborne pathogen. Swine are the main reservoir of zoonotic HEV. In humans, HEV infection is usually asymptomatic or causes acute hepatitis that is self-limited. However, fulminant hepatic failure and chronic cases of HEV infection can occur in some patients. In contrast, HEV infection in pigs remains asymptomatic, although the virus replicates efficiently, suggesting that swine are able to control the virus pathogenesis. Upon viral infection, IFN is secreted and activates cellular pathways leading to the expression of many IFN-stimulated genes (ISGs). ISGs can restrict the replication of specific viruses and establish an antiviral state within infected and neighboring cells.

Methods

In this study, we used PCR arrays to determine the expression level of up to 168 ISGs and other IFN-related genes in the liver tissues of pigs infected with zoonotic HEV-3c and HEV-3f and in human bipotent liver HepaRG cells persistently infected with HEV-3f.

Results and discussion

The expression of 12 and 25 ISGs was found to be up-regulated in infected swine livers and HepaRG cells, respectively. The expression of CXCL10, IFIT2, MX2, OASL and OAS2 was up-regulated in both species. Increased expression of IFI16 mRNA was also found in swine liver tissues. This study contributes to the identification of potential ISGs that could play a role in the control or persistence of HEV infection.

Understanding yellow fever-associated myocardial injury: an autopsy study

BACKGROUND

Yellow fever (YF) is a viral hemorrhagic fever, endemic in parts of South America and Africa. There is scarce evidence about the pathogenesis of the myocardial injury. The objective of this study is to evaluate the cardiac pathology in fatal cases of YF.

METHODS

This retrospective autopsy study included cases from the São Paulo (Brazil) epidemic of 2017-2019. We reviewed medical records and performed cardiac tissue histopathological evaluation, electron microscopy, immunohistochemical assays, RT-qPCR for YF virus (YFV)-RNA, and proteomics analysis on inflammatory and endothelial biomarkers.

FINDINGS

Seventy-three confirmed YF cases with a median age of 48 (34-60) years were included. We observed myocardial fibrosis in 68 (93.2%) patients; cardiomyocyte hypertrophy in 68 (93.2%); endothelial alterations in 67 (91.8%); fiber necrosis in 50 (68.5%); viral myocarditis in 9 (12.3%); and secondary myocarditis in 5 (6.8%). Four out of five patients with 17DD vaccine-associated viscerotropic disease presented with myocarditis. The cardiac conduction system showed edema, hemorrhages and endothelial fibrinoid necrosis. Immunohistochemistry detected CD68-positive inflammatory interstitial cells and YFV antigens in endothelial and inflammatory cells. YFV-RNA was detected positive in 95.7% of the cardiac samples. The proteomics analysis demonstrated that YF patients had higher levels of multiple inflammatory and endothelial biomarkers in comparison to cardiovascular controls, and higher levels of interferon gamma-induced protein 10 (IP-10) in comparison to sepsis (p = 0.01) and cardiovascular controls (p < 0.001) in Dunn test.

INTERPRETATION

Myocardial injury is frequent in severe YF, due to multifactorial mechanisms, including direct YFV-mediated damage, endothelial cell injury, and inflammatory response, with a possible prominent role for IP-10.

FUNDING

This study was funded by Fundação de Amparo à Pesquisa do Estado de São Paulo, Bill and Melinda Gates Foundation, Conselho Nacional de Desenvolvimento Científico e Tecnológico, Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.

GATA1-defective immune-megakaryocytes as possible drivers of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disorder with limited therapeutic options. Insufficient understanding of driver mutations and poor fidelity of currently available animal models has limited the development of effective therapies. Since GATA1 deficient megakaryocytes sustain myelofibrosis, we hypothesized that they may also induce fibrosis in lungs. We discovered that lungs from IPF patients and Gata1low mice contain numerous GATA1negative immune-poised megakaryocytes that, in mice, have defective RNA-seq profiling and increased TGF-β1, CXCL1 and P-selectin content. With age, Gata1low mice develop fibrosis in lungs. Development of lung fibrosis in this model is prevented by P-selectin deletion and rescued by P-selectin, TGF-β1 or CXCL1 inhibition. Mechanistically, P-selectin inhibition decreases TGF-β1 and CXCL1 content and increases GATA1positive megakaryocytes while TGF-β1 or CXCL1 inhibition decreased CXCL1 only. In conclusion, Gata1low mice are a novel genetic-driven model for IPF and provide a link between abnormal immune-megakaryocytes and lung fibrosis.

YKL-40 promotes chemokine expression following drug-induced liver injury via TF-PAR1 pathway in mice

Background: The inflammatory factor YKL-40 is associated with various inflammatory diseases and is key to remodeling inflammatory cells and tissues. YKL-40 (Chi3l1) promotes the activation of tissue factor (TF), leading to intrahepatic vascular coagulation (IAOC) and liver injury. TF is a key promoter of the exogenous coagulation cascade and is also involved in several signaling involving cell proliferation, apoptosis, charring, migration and inflammatory diseases pathways. However, the effect of YKL-40-induced TF-PAR1 pathway on the expression of downstream chemokines remains unknown. Methods: We established a liver injury model using Concanavalin A (ConA) in C57 BL/6 mice. By adopting various experimental techniques, the effect of YKL-40 induced TF-PAR1 pathway on the expression of downstream chemokine ligand 2 (CCL2) and IP-10 was verified. Results: We found that overexpression of YKL-40 increased the expression of TF, protease-activated receptor 1 (PAR1), CCL2 and IP-10 in mice and exacerbated the severity of liver injury. However, blocking the expression of TF significantly reversed the extent of liver injury. Conclusion: We found that YKL-40 promotes the expression of downstream chemokines ligand 2 (CCL2) and IP-10 by activating the TF-PAR1 pathway, leading to increased recruitment of inflammatory cells and exacerbating the progression of liver injury. This provides a new approach for the clinical treatment of drug-induced liver injury.

COVID-19 Biomarkers at the Crossroad between Patient Stratification and Targeted Therapy: The Role of Validated and Proposed Parameters

Clinical knowledge about SARS-CoV-2 infection mechanisms and COVID-19 pathophysiology have enormously increased during the pandemic. Nevertheless, because of the great heterogeneity of disease manifestations, a precise patient stratification at admission is still difficult, thus rendering a rational allocation of limited medical resources as well as a tailored therapeutic approach challenging. To date, many hematologic biomarkers have been validated to support the early triage of SARS-CoV-2-positive patients and to monitor their disease progression. Among them, some indices have proven to be not only predictive parameters, but also direct or indirect pharmacological targets, thus allowing for a more tailored approach to single-patient symptoms, especially in those with severe progressive disease. While many blood test-derived parameters quickly entered routine clinical practice, other circulating biomarkers have been proposed by several researchers who have investigated their reliability in specific patient cohorts. Despite their usefulness in specific contexts as well as their potential interest as therapeutic targets, such experimental markers have not been implemented in routine clinical practice, mainly due to their higher costs and low availability in general hospital settings. This narrative review will present an overview of the most commonly adopted biomarkers in clinical practice and of the most promising ones emerging from specific population studies. Considering that each of the validated markers reflects a specific aspect of COVID-19 evolution, embedding new highly informative markers into routine clinical testing could help not only in early patient stratification, but also in guiding a timely and tailored method of therapeutic intervention.