Regulation of type I interferon responses

Impaired Aire-dependent IFN signaling in the thymus precedes the protective autoantibodies to IFNα

Recent studies have highlighted the role of the thymus in maintaining immune tolerance to type 1 interferons (T1 IFNs). Individuals with thymic abnormalities, such as autoimmune regulator (AIRE) gene mutations, frequently develop neutralizing autoantibodies to interferon-alpha (IFNα). Unlike mice, Aire-deficient rats develop robust autoantibodies to IFNα. Using this rat model, we show that Aire regulates the thymic expression of interferon-stimulated genes (ISGs), which occurs before developing anti-IFNα autoantibodies. In the periphery, we observed a widespread downregulation of ISGs across immune cells and reduced activation of natural killer (NK) cells. Furthermore, the presence of anti-IFNα autoantibodies correlated with reduced peripheral tissue inflammation, suggesting their role in dampening T1 IFN signaling and minimizing tissue infiltration. Our findings reveal that Aire-mediated regulation of thymic T1 IFN signaling is linked to the production of protective anti-IFNα autoantibodies, which inversely correlate with autoimmune pathology in peripheral tissues.

Cyclophilin D knockdown/knockout promotes microglia M2 polarization by inhibiting STAT1 to alleviate neuroinflammation in neonatal white matter injury

The activation of microglia cells is intimately associated with the pathophysiology of neuroinflammation and neonatal white matter injury (WMI). Cyclophilin D (CypD), a matrix cyclophilin, is known to be one of the important regulators of mitochondrial permeability transition pore. Currently, CypD has been discovered the function of regulating inflammation. However, its impact on microglia in the context of neonatal WMI remains unclear. In our study, CypD inhibition ameliorated microglia activation, decreased pro-inflammatory factor levels, and increased anti-inflammatory factor levels in both neonatal WMI mice and oxygen glucose deprivation/reperfusion (OGD/R)-induced BV2 microglial cells. CypD knockout promoted myelination and rescued neurological function in mice following hypoxic-ischemic injury. In addition, CypD knockdown alleviated mitochondrial dysfunction of BV2 microglial cells. RNA-Seq indicated that CypD inhibition downregulated STAT1. Western blotting results verified that CypD inhibition significantly downregulated the phosphorylation level of STAT1. Our research revealed the protective role of CypD inhibition in neuroinflammation and mitochondrial function of microglia. Targeting CypD expression in microglia may be a potential therapeutic option for neonatal WMI.

Pegylated Interferons: Still a Major Player for the Treatment of Myeloproliferative Neoplasms

Over the past 35 years, interferons have been explored in various formulations for the management of Philadelphia chromosome-negative myeloproliferative neoplasms (MPNs), such as essential thrombocythemia (ET), polycythemia vera (PV), and myelofibrosis, and remain a key tool in caring for patients with these diseases. These agents are excellent cytoreductive agents with high rates of hematologic response, are helpful in symptom management, and have a long track record of safety and manageable toxicities. More recently, they have shown promise in sustaining responses over many years, with associated reductions in driver mutations (JAK2, MPL, CALR) of these diseases, particularly in PV and ET. Since reductions in molecular mutant allele burden have been correlated with several response outcomes such as reductions in both thrombotic risk and disease progression, there is emerging proof that interferons may offer disease-modifying activity. These long-term benefits and their use as the preferred agent in young pregnant women who need cytoreduction make interferons often the first choice in young adult population who harbor a lifetime risk of progression. Looking forward, the prospect of sustained treatment-free responses, like chronic myeloid leukemia after deep molecular response, and normal life expectancy may also be on the frontier. Despite relative rookies such as JAK inhibitors in the MPN landscape, the veteran in the game, interferon, remains a key player.

A gut-wrenching tale of neuronal distress

Neurons innervating the gut are on the frontlines of host-microbe interactions and thus exposed to a myriad of inflammatory and infectious insults. In this issue of Neuron, Forster, Jakob et al.1 reveal that diverse populations of gut-innervating neurons exhibit conserved responses to inflammation, linking interferon signaling to ferroptosis.

Pharmacological inhibition of tyrosine protein-kinase 2 reduces islet inflammation and delays type 1 diabetes onset in mice

BACKGROUND

Tyrosine protein-kinase 2 (TYK2) mediates inflammatory signalling through multiple cytokines, including interferon-α (IFNα), interleukin (IL)-12, and IL-23. TYK2 missense mutations protect against type 1 diabetes (T1D), and inhibition of TYK2 shows promise in other autoimmune conditions.

METHODS

We evaluated the effects of specific TYK2 inhibitors (TYK2is) in pre-clinical models of T1D, including human β cells, cadaveric islets, iPSC-derived islets, and mouse models.

FINDINGS

In vitro studies showed that TYK2is prevented IFNα-induced β cell HLA class I up-regulation, endoplasmic reticulum stress, and chemokine production. In co-culture studies, pre-treatment of β cells with TYK2i prevented IFNα-induced antigenic peptide presentation and alloreactive and autoreactive T cell degranulation. In vivo administration of BMS-986202 in two mouse models of T1D (RIP-LCMV-GP and NOD mice) reduced systemic and tissue-localised inflammation, prevented β cell death, and delayed T1D onset. Transcriptional phenotyping of pancreatic islets, pancreatic lymph nodes, and spleen highlighted a role for TYK2 inhibition in modulating signalling pathways associated with inflammation, translational control, stress signalling, secretory function, immunity, and diabetes. Additionally, TYK2i treatment changed the composition of innate and adaptive immune cell populations in the blood and disease target tissues.

INTERPRETATION

These findings indicate that TYK2i has beneficial effects on both the immune and endocrine compartments in models of T1D, thus supporting a path forward for testing TYK2is in human T1D.

FUNDING

This work was supported by the National Institutes of Health (NIH), Veteran Affairs (VA), Breakthrough T1D, and gifts from the Sigma Beta Sorority, the Ball Brothers Foundation, and the George and Frances Ball Foundation.

VAPA suppresses BEFV and VSV-induced type I IFNs signaling response by targeting JAK1 for NEDD4-mediated ubiquitin-proteasome degradation

VAMP-associated protein A (VAPA) binds to various proteins involved in multiple cellular processes, however, its role in the regulation of type I interferons (IFN-I) signaling has not been elucidated. In this study, we demonstrate that VAPA negatively regulates the IFN-I signaling during bovine epidemic fever virus (BEFV) and vesicular stomatitis virus (VSV) infection. Upon treatment with IFN-β, VAPA negatively regulates the JAK-STAT signaling pathway. Further studies show that VAPA inhibits the IFN-I signaling by promoting the degradation of JAK1 through the ubiquitin-proteasome system during BEFV and VSV infection. Mechanistically, VAPA facilitates the interaction between the E3 ubiquitin ligase NEDD4 and JAK1, thereby enhancing the ubiquitination and subsequent degradation of JAK1. Furthermore, viral titers are markedly reduced, and the promoting effect of VAPA on VSV or BEFV replication is attenuated in NEDD4-deficient cells. Taken together, our findings reveal a novel role for VAPA in negatively regulating the IFN-I signaling response and provide a molecular basis for the design of targeted antiviral agents.

Mouse models of Tembusu virus infection for differentiating between cluster 2.1 and 2.2 isolates

Tembusu virus (TMUV) cluster 2.1 and 2.2 strains are known to produce lethal neurological disease in mice inoculated by intracerebral (ic) route. Here, we report the comparative clinicopathological findings following experimental infections of 3-week-old BALB/c and Kunming mice with cluster 2.1 isolate H and cluster 2.2 isolate Y. When infected by the subcutaneous (sc) route, both isolates failed to induce disease in mice. When infected by the ic route, both isolates caused lethal neurological disease in mice, with isolate H presenting markedly higher neurovirulence than isolate Y. Further studies with the Kunming mouse model showed that following sc inoculation, both H and Y isolates failed to replicate in brain and spleen, and that following ic inoculation, isolate H replicated to higher levels in brain and spleen than isolate Y. The findings may help to explain non-neuroinvasive property of clusters 2.1 and 2.2 and suggest that enhanced neurovirulence of cluster 2.1 relative to cluster 2.2 is associated with more efficient replication in the central nervous system and in the periphery. Moreover, isolate H induced significantly higher levels of IFN-β, IL-1β, IL-6, TNF-α, Ifit1, and Ifit2 expression relative to isolate Y, indicating a positive correlation between TMUV neurovirulence and magnitude of antiviral innate immune response. The present work demonstrates that the mouse models allow to differentiate between cluster 2.1 and 2.2 isolates and provides mechanistic insights into TMUV-induced disease.

Mycoplasma hyopneumoniae nuclease Mhp597 negatively regulates TBK1-IRF3-IFN-I pathway by targeting vimentin to facilitate infection

Infection with Mycoplasma hyopneumoniae (M. hyopneumoniae) leads to chronic infectious pneumonia in pigs, resulting in significant distress and economic losses in the global pig industry. The pathogen secretes various proteins, including toxins, adhesins, and virulence-related enzymes, which facilitate adhesion, invasion, and immune evasion processes between bacteria and the host. However, the effector proteins of M. hyopneumoniae are predominantly uncharacterized. In this study, we demonstrate that the nuclease Mhp597 functions as a potential effector protein of M. hyopneumoniae, and we elucidate its mechanism of action in facilitating immune evasion. Our findings indicate that Mhp597 exhibits high expression efficiency in host cells and significantly inhibits IFN-α and IFN-β protein expression. Using yeast two-hybrid and co-immunoprecipitation experiments, we established that Mhp597 interacts with porcine alveolar macrophage vimentin (Vim) via specific amino acid residues (Arg 232, Lys 256, Phe 263, and Lys 317). Further analysis revealed that Mhp597 inhibited the phosphorylation of TBK1 and IRF3 via Vim, thereby suppressing type I interferon (IFN-I) production and promoting the proliferation of M. hyopneumoniae within host cells. In conclusion, this study provides the first detailed account of the molecular mechanism by which Mhp597 negatively regulates the TBK1-IRF3-IFN-I signaling pathway through Vim, thus facilitating immune evasion and proliferation of M. hyopneumoniae within host cells. These findings enhance our understanding of the pathogenic mechanisms of M. hyopneumoniae and suggest potential molecular targets for the development of novel therapeutic strategies.

A novel homozygous ISG15 missense variant leads to severe inflammatory skin lesions, interstitial pneumonia, and basal ganglia calcifications in a Chinese infant with ISG15 deficiency

Type I interferonopathies are a group of rare inherited autoinflammatory disorders characterized by dysregulation of type I interferon (IFN-I) signaling pathways. ISG15, a unique ubiquitin-like (Ubl) modifier in the interferon-stimulated genes (ISGs) family, plays a critical role in innate immune responses induced by IFN-I. When ISG15 function is impaired, it results in a disorder known as ISG15 deficiency, which is classified as an autosomal recessive systemic type I interferonopathy. Here, we report a 4-month-old Chinese patient presenting with inflammatory skin lesions, interstitial pneumonia, and basal ganglia calcifications. Whole-exome sequencing (WES) identified a novel homozygous missense variant (NM_005101.4: exon2: c.392 T > C, p.Leu131Pro) of ISG15. Functional analysis revealed that this variant impaired ISGylation and disrupted the stabilization of USP18, leading to defective negative regulation of IFN-I signaling and consequent excessive IFN-I production. Consistent with this, the patient exhibited elevated expression of ISGs in both peripheral blood and peripheral blood mononuclear cells (PBMCs). Treatment with the Janus kinase (JAK) inhibitor baricitinib rapidly resolved the patient's clinical symptoms. In conclusion, our findings expand the pathogenic spectrum of ISG15 deficiency and highlight the therapeutic efficacy of baricitinib in this disease. Notably, this case represents the first reported instance of a homozygous ISG15 missense variant in the Chinese population and the third such variant reported worldwide, further enriching our understanding of this rare autoinflammatory disease.

Targeting CTP synthetase 1 to restore interferon induction and impede nucleotide synthesis in SARS-CoV-2 infection

Despite the global impact caused by the most recent SARS-CoV-2 pandemic, our knowledge of the molecular underpinnings of its highly infectious nature remains incomplete. We report here that SARS-CoV-2 exploits cellular CTP synthetase 1 (CTPS1) to promote CTP synthesis and suppress interferon (IFN) induction. In addition to catalyzing CTP synthesis, CTPS1 also deamidates interferon regulatory factor 3 (IRF3) to dampen interferon induction. Screening a SARS-CoV-2 expression library, we identified several viral proteins that interact with CTPS1. Functional analyses demonstrate that ORF8 and Nsp8 activate CTPS1 to deamidate IRF3 and negate IFN induction, whereas ORF7b and ORF8 activate CTPS1 to promote CTP synthesis. These results highlight CTPS1 as a signaling node that integrates cellular metabolism and innate immune response. Indeed, small-molecule inhibitors of CTPS1 deplete CTP and boost IFN induction in SARS-CoV-2-infected cells, thus effectively impeding SARS-CoV-2 replication and pathogenesis in mouse models. Our work uncovers an intricate mechanism by which a viral pathogen couples immune evasion to metabolic activation to fuel viral replication. Inhibition of the cellular CTPS1 offers an attractive means to develop antiviral therapy against highly mutagenic viruses.IMPORTANCEOur understanding of the underpinnings of highly infectious SARS-CoV-2 is rudimentary at best. We report here that SARS-CoV-2 activates CTPS1 to promote CTP synthesis and suppress IFN induction, thus coupling immune evasion to activated nucleotide synthesis. Inhibition of the key metabolic enzyme not only depletes the nucleotide pool but also boosts host antiviral defense, thereby impeding SARS-CoV-2 replication. Targeting cellular enzymes presents a strategy to counter the rapidly evolving SARS-CoV-2 variants.

Unveiling hub genes and biological pathways: A bioinformatics analysis of Trauma-Induced Coagulopathy (TIC)

BACKGROUND

Trauma-Induced Coagulopathy is a severe condition that rapidly manifests following traumatic injury and is characterized by shock, hypoperfusion, and vascular damage. This study employed bioinformatics methods to identify crucial hub genes and pathways associated with TIC.

METHODS

Microarray datasets (accession number GSE223245) were obtained from the Gene Expression Omnibus (GEO) database. The data were subjected analyses to identify the Differentially Expressed Genes (DEGs), which were further subjected to GO and KEGG pathway analyses. Subsequently, a Protein-Protein Interaction (PPI) network was constructed and hub DEGs closely linked to TIC were identified using CytoHubba, MCODE, and CTD scores. The diagnostic value of these hub genes was evaluated using Receiver Operating Characteristic (ROC) analysis.

RESULTS

Among the analyzed genes, 269 were identified as DEGs, comprising 103 upregulated and 739 downregulated genes. Notably, several significant hub genes were associated with the development of TIC, as revealed by bioinformatic analyses.

CONCLUSIONS

This study highlights the critical impact of newly discovered genes on the development and progression of TIC. Further validation through experimental research and clinical trials is required to confirm these findings.

Dissecting inflammation in the immunemetabolomic era

The role of immune metabolism, specific metabolites and cell-intrinsic and -extrinsic metabolic states across the time course of an inflammatory response are emerging knowledge. Targeted and untargeted metabolomic analysis is essential to understand how immune cells adapt their metabolic program throughout an immune response. In addition, metabolomic analysis can aid to identify pathophysiological patterns in inflammatory disease. Here, we discuss new metabolomic findings within the transition from inflammation to resolution, focusing on three key programs of immunity: Efferocytosis, IL-10 signaling and trained immunity. Particularly the tryptophan-derived metabolite kynurenine was identified as essential for efferocytosis and inflammation resolution as well as a potential biomarker in diverse inflammatory conditions. In summary, metabolomic analysis and integration with transcriptomic and proteomic data, high resolution imaging and spatial information is key to unravel metabolic drivers and dependencies during inflammation and progression to tissue-repair.

Nanoparticle-Based Strategies to Enhance the Efficacy of STING Activators in Cancer Immunotherapy

The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) pathway plays a critical role in triggering innate and adaptive immune responses through type I interferon activation and immune cell recruitment, holding significant promise for cancer therapy. While STING activators targeting this pathway have been developed, their clinical application is hindered by challenges such as poor membrane permeability, rapid degradation, suboptimal pharmacokinetics, off-target biodistribution, and toxicity. Nanoparticle-based delivery systems offer a promising solution by enhancing the stability, circulation time, tumor accumulation, and intracellular release of STING activators. Furthermore, combining nanoparticle-delivered STING activators with radiotherapy, chemotherapy, phototherapy, and other immunotherapies enables synergistic antitumor effects through multimodal mechanisms, addressing resistance to monotherapies and reducing risks of recurrence and metastasis. This review outlines the immunomodulatory mechanisms of the cGAS-STING pathway, surveys current STING-targeted activators, and comprehensively discusses recent advances in nanoparticle-mediated delivery strategies for STING activation. Additionally, we explore combinatorial approaches that integrate STING-targeted nanotherapies with conventional and emerging treatments. Finally, we highlight the current status, prospects, and challenges of nanoparticle-based STING activation for cancer immunotherapy.

Curcumin activates the JAK-STAT signaling pathway to enhance the innate immune response against porcine epidemic diarrhea virus infection in vivo and in vitro

Porcine epidemic diarrhea (PED) is a highly pathogenic infectious disease caused by porcine epidemic diarrhea virus (PEDV), which has caused significant economic losses to the global pig industry. Due to the high mutability of the PEDV genome, the development of effective vaccines or drugs to prevent and control PEDV is still facing great difficulties. In this study, we found that the natural compound curcumin showed effective antiviral activity against PEDV in VERO-E6 and IPEC-J2 cells. The Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) signaling pathway was screened by transcriptomics as a potential innate immune mechanism of IPEC-J2 cells against PEDV infection. For PEDV, a highly pathogenic virus, cellular autoimmune response is not sufficient to fight against its infection. Our results demonstrated that curcumin could exert antiviral effects by enhancing the JAK-STAT cascade reaction mediated by type I interferon IFN-α and IFN-β in IPEC-J2 cells. In vivo experiments further confirmed the protective effect of curcumin on PEDV-infected piglets and its positive regulation of the JAK-STAT signaling pathway. In vivo, curcumin prophylaxis significantly enhanced IFN-α and IFN-β-induced JAK-STAT signaling and the production of interferon-stimulated genes (ISGs), and increased the innate immune response, thus exerting antiviral effects effectively. In conclusion, our data indicate that curcumin can effectively resist PEDV infection in IPEC-J2 cells and piglets, which provides a new reference for the development of anti-PEDV drugs with important application prospects.

The role of double-negative B cells in the pathogenesis of systemic lupus erythematosus

B cells are essential to the pathophysiology of systemic lupus erythematosus (SLE), a chronic autoimmune illness. IgD-CD27-double negative B cells (DNB cells) are one of the aberrant B cell subsets linked to SLE that have attracted much scientific interest. There is growing evidence that DNB cells play a significant role in the development of the disease and are strongly linked to the activity of lupus. These cells play a pivotal role in the pathogenesis of SLE by producing a diverse array of autoantibodies, which form immune complexes that drive target organ damage. A comprehensive understanding of SLE pathophysiology necessitates in-depth investigation into DNB cells, not only to elucidate their mechanistic contributions but also to uncover novel therapeutic strategies. According to available data, treatments that target B cells have proven effective in managing SLE; nevertheless, a significant breakthrough in precision medicine for SLE may come from targeting DNB cells specifically. Despite growing interest in DNB cells, their precise characteristics, developmental trajectories, and regulatory mechanisms remain incompletely defined, posing significant challenges to the field. A comprehensive investigation of the regulatory mechanisms governing DNB cell differentiation and expansion in SLE may facilitate novel therapeutic discoveries. This review aims to provide an updated synthesis of current research on DNB cells, with a focus on their origins, developmental trajectories in SLE, and potential as precision therapeutic targets.

Electron Pump and Photon Trap Effect-Derived Selective Antitumor of Fe-Ppy@CaO2-Modified Polyetheretherketone for Bone Tumor Therapy

Bone tumors with high mortality and disability have become a major clinical challenge. Herewith, it is necessary to design materials for bone tumor therapy and bone repair. In this work, Fe-doped polypyrrole (Fe-Ppy) and CaO2 are constructed on sulfonated polyetheretherketone (SP) to form a multistage-responsive coating. The coating achieves long-lasting antitumor through chemodynamic therapy (CDT), photothermal therapy (PTT), and combined immunotherapy. Fe-Ppy acts as an electron pump to replenish Fe2+ through oxidizing -NH- to -N+-, which lasts the Fenton reaction and persistently produces reactive oxygen species (ROS) in the tumor microenvironment (TME). CaO2 selectively provides exogenous H2O2 in response to TME to boost the electron cycle. Stronger near-infrared light absorption due to Fe doping and more photon traps caused by porous structure-induced scattering and refraction diminishment improve the photothermal conversion of modified SP. Furthermore, long-lasting ROS and effective photothermal conversion enhance M1 activation to secrete TNF-α and IFN to kill tumor cells. After tumor therapy, Fe-Ppy@CaO2-modified SP could adaptively switch the macrophage to M2 and promote osteogenesis with the abolishment of TME and NIR stimulation. In summary, Fe-Ppy@CaO2-modified SP with long-lasting ROS, enhanced photothermal conversion, and immunomodulation is a potential candidate for bone tumor therapy and tissue repair.

Human papillomavirus E1 proteins inhibit RIG-I/MDA5-MAVS, TLR3-TRIF, cGAS-STING, and JAK-STAT signaling pathways to evade innate antiviral immunity

Human papillomavirus (HPV) is a major etiological agent of both malignant and benign lesions, with high-risk types, such as HPV16 and HPV18, being strongly linked to cervical cancer, while low-risk types like HPV11 are associated with benign conditions. While viral proteins such as E6 and E7 are well-established regulators of immune evasion, the role of E1 in modulating the host antiviral responses remains insufficiently characterized. This study investigates the immunomodulatory functions of HPV16 and HPV11 E1 in suppressing innate antiviral immune signaling pathways. Through a combination of RT-qPCR and luciferase reporter assays, we demonstrate that E1 suppresses the production of interferons and interferon-stimulated genes triggered by viral infections and the activation of RIG-I/MDA5-MAVS, TLR3-TRIF, cGAS-STING, and JAK-STAT pathways. Co-immunoprecipitation assays reveal that E1 interacts directly with key signaling molecules within these pathways. E1 also impairs TBK1 and IRF3 phosphorylation and obstructs the nuclear translocation of IRF3, thereby broadly suppressing IFN responses. Additionally, E1 disrupts the JAK-STAT pathway by binding STAT1, which prevents the assembly and nuclear localization of the ISGF3 complex containing STAT1, STAT2, and IRF9, thereby further diminishing antiviral response. These findings establish E1 as a pivotal regulator of immune evasion and suggest its potential as a novel therapeutic target to enhance antiviral immunity in HPV-associated diseases.

Bilirubin metabolism in the liver orchestrates antiviral innate immunity in the body

Bilirubin metabolism crucially maintains normal liver function, but whether it contributes to antiviral immunity remains unknown. Here, we reveal that the liver bilirubin metabolic pathway facilitates antiviral innate immunity of the body. We discovered that viral infection upregulates uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) expression in the liver, which in turn stabilizes IRF3 proteins to promote type I interferon (IFN-I) production. Moreover, we found that serum unconjugated bilirubin (UCB), a unique physiological substrate of UGT1A1, can competitively inhibit the binding of IFN-I to IFN-I receptor 2 (IFNAR2), thus attenuating IFN-I-induced antiviral signaling of the body. Accordingly, effective bilirubin metabolism in the liver promotes antiviral immunity of the body by specifically employing liver UGT1A1-mediated enhancement of IFN-I production and reducing serum bilirubin-mediated inhibition of IFN-I signaling. This study uncovers the significance of bilirubin metabolism in antiviral innate immunity and demonstrates that conventional IFN-I therapy is less efficient for patients with hepatitis B virus (HBV) with high levels of bilirubin.

Type I interferon regulation of group I ILC subsets during both homeostasis and cytomegalovirus infection

Type 1 innate lymphoid cells (ILC1s) and conventional natural killer cells belong to the group 1 ILCs (gILC1), characterized largely by T-bet expression and interferon γ secretion. While much has been done to define factors that regulate the development, differentiation, and effector functions of both cell types, little is known about what controls gILC1 homeostasis. Here, mixed bone marrow chimeras were used to define the role of type I interferon receptor (IFNAR) signaling in regulating gILC1 in the spleen and liver at homeostasis and during murine cytomegalovirus infection. We show that basal IFNAR signaling induces cell and tissue-specific phenotypic changes in gILC1, inhibiting bona-fide ILC1 markers (CD49a, CD200R, CXCR6) and regulating expression of perforin and granzymes B and C. Finally, while IFNAR signaling enhances cytokine responsiveness in vitro in both gILC1 subsets, it has a dichotomous effect on interferon γ production during murine cytomegalovirus infection, stimulating it in conventional natural killer cells and inhibiting it in ILC1.

Disease-specific B cell clones are shared between patients with Crohn's disease

B cells have important functions in gut homeostasis, and dysregulated B cell populations are frequently observed in patients with inflammatory bowel diseases, including both ulcerative colitis (UC) and Crohn's disease (CD). How these B cell perturbations contribute to disease remains largely unknown. Here, we perform deep sequencing of the B cell receptor (BCR) repertoire in four cohorts of patients with CD, together with healthy controls and patients with UC. We identify BCR clones that are shared between patients with CD but not found in healthy individuals nor in patients with UC, indicating CD-associated B cell immune responses. Shared clones are present in the inflamed gut mucosa, draining intestinal lymph nodes and blood, suggesting the presence of common CD-associated antigens that drive B cell responses in CD patients.

Deep insight into cytokine storm: from pathogenesis to treatment

Cytokine storm (CS) is a severe systemic inflammatory syndrome characterized by the excessive activation of immune cells and a significant increase in circulating levels of cytokines. This pathological process is implicated in the development of life-threatening conditions such as fulminant myocarditis (FM), acute respiratory distress syndrome (ARDS), primary or secondary hemophagocytic lymphohistiocytosis (HLH), cytokine release syndrome (CRS) associated with chimeric antigen receptor-modified T (CAR-T) therapy, and grade III to IV acute graft-versus-host disease following allogeneic hematopoietic stem cell transplantation. The significant involvement of the JAK-STAT pathway, Toll-like receptors, neutrophil extracellular traps, NLRP3 inflammasome, and other signaling pathways has been recognized in the pathogenesis of CS. Therapies targeting these pathways have been developed or are currently being investigated. While novel drugs have demonstrated promising therapeutic efficacy in mitigating CS, the overall mortality rate of CS resulting from underlying diseases remains high. In the clinical setting, the management of CS typically necessitates a multidisciplinary team strategy encompassing the removal of abnormal inflammatory or immune system activation, the preservation of vital organ function, the treatment of the underlying disease, and the provision of life supportive therapy. This review provides a comprehensive overview of the key signaling pathways and associated cytokines implicated in CS, elucidates the impact of dysregulated immune cell activation, and delineates the resultant organ injury associated with CS. In addition, we offer insights and current literature on the management of CS in cases of FM, ARDS, systemic inflammatory response syndrome, treatment-induced CRS, HLH, and other related conditions.

Human long noncoding RNA VILMIR is induced by major respiratory viral infections and modulates the host interferon response

Long noncoding RNAs (lncRNAs) are a newer class of noncoding transcripts identified as key regulators of biological processes. Here, we aimed to identify novel lncRNA targets that play critical roles in major human respiratory viral infections by systematically mining large-scale transcriptomic data sets. Using bulk RNA-sequencing (RNA-seq) analysis, we identified a previously uncharacterized lncRNA, named virus-inducible lncRNA modulator of interferon response (VILMIR), that was consistently upregulated after in vitro influenza infection across multiple human epithelial cell lines and influenza A virus subtypes. VILMIR was also upregulated after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) infections in vitro. We experimentally confirmed the response of VILMIR to influenza infection and interferon-beta (IFN-β) treatment in the A549 human epithelial cell line and found the expression of VILMIR was robustly induced by IFN-β treatment in a dose- and time-specific manner. Single-cell RNA-seq analysis of bronchoalveolar lavage fluid samples from coronavirus disease 2019 (COVID-19) patients uncovered that VILMIR was upregulated across various cell types, including at least five immune cells. The upregulation of VILMIR in immune cells was further confirmed in the human T cell and monocyte cell lines, SUP-T1 and THP-1, after IFN-β treatment. Finally, we found that knockdown of VILMIR expression reduced the magnitude of host transcriptional responses to both IFN-β treatment and influenza A virus infection in A549 cells. Together, our results show that VILMIR is a novel interferon-stimulated gene (ISG) that regulates the host interferon response and may be a potential therapeutic target for human respiratory viral infections upon further mechanistic investigation.IMPORTANCEIdentifying host factors that regulate the immune response to human respiratory viral infection is critical to developing new therapeutics. Human long noncoding RNAs (lncRNAs) have been found to play key regulatory roles during biological processes; however, the majority of lncRNA functions within the host antiviral response remain unknown. In this study, we identified that a previously uncharacterized lncRNA, virus-inducible lncRNA modulator of interferon response (VILMIR), is upregulated after major respiratory viral infections including influenza, severe acute respiratory syndrome coronavirus 2, and respiratory syncytial virus. We demonstrated that VILMIR is an interferon-stimulated gene that is upregulated after interferon-beta (IFN-β) in several human cell types. We also found that knockdown of VILMIR reduced the magnitude of host transcriptional responses to IFN-β treatment and influenza A infection in human epithelial cells. Our results reveal that VILMIR regulates the host interferon response and may present a new therapeutic target during human respiratory viral infections.

Hepatitis B surface antigen hijacks TANK-binding kinase 1 to suppress type I interferon and induce early autophagy

There are close links between innate immunity and autophagy. However, the crosstalk between innate immunity and autophagy in host cells infected with hepatitis B virus (HBV) remains unclear. Here, we reported that HBsAg suppressed type I interferon production and induced the accumulation of autophagosomes. HBsAg boosted TANK-binding kinase 1 (TBK1) phosphorylation and depressed interferon regulatory factor 3 (IRF3) phosphorylation ex vivo and in vivo. Mechanistic studies showed that HBsAg interaction with the kinase domain (KD) of TBK1 augmented its dimerization but disrupted TBK1-IRF3 complexes. Using the TBK1 inhibitor, BX795, we discovered that HBsAg-enhanced TBK1 dimerization, promoting sequestosome-1 (p62) phosphorylation, was necessary for HBV-induced autophagy and HBV replication. Moreover, HBsAg blocked autophagosome-lysosome fusion by inhibiting the synaptosomal-associated protein 29 (SNAP29) promoter. Notably, liver tissues from HBsAg transgenic mice or chronic HBV patients revealed that IFNβ signaling was inhibited and incomplete autophagy was induced. These findings suggest a novel mechanism by which HBsAg targets TBK1 to inhibit type I interferon and induce early autophagy, possibly leading to persistent HBV infection. Molecular mechanisms of HBsAg suppression of the IFNβ signaling pathway and triggering of early autophagy. HBsAg targets the kinase domain of TBK1, thereby disrupting the TBK1-IRF3 complex and inhibiting type I interferon production. On the other hand, HBsAg enhances TBK1 dimerization and phosphorylation, which upregulates the phosphorylation of p62 to induce p62-mediated autophagy. Furthermore, HBV infection causes the accumulation of autophagosomes. This is achieved by HBsAg suppressing the SNAP29 promoter activity, which blocks autophagosome-lysosome fusion.

CMTM4 promotes PD-L1-mediated macrophage apoptosis by enhancing STAT2 phosphorylation in sepsis

BACKGROUND

Macrophage apoptosis is a key contributor to the elimination of immune cells and increased susceptibility during sepsis. CKLF like MARVEL transmembrane domain containing 4 (CMTM4) is a membrane protein with four transmembrane domains. It has recently been implicated in the regulation of immune cell biological functions. However, its role in regulating macrophage apoptosis during sepsis has not been extensively studied.

METHODS

Clinical samples were analyzed to determine CMTM4 expression levels and their correlation with clinical examination results. An in vitro model was developed using C57BL/6 mice and the THP-1 cell line. An immunofluorescence analysis was used to assess protein expression levels, apoptosis, and protein co-localization. Western blotting (WB) was used to measure protein expression levels, while flow cytometry was used to detect cell apoptosis. Transcriptomic sequencing was conducted to identify differentially expressed genes and to perform a functional enrichment analysis. Transcription factors were screened using databases. Chromatin immunoprecipitation, followed by quantitative PCR (ChIP-qPCR), was conducted to analyze protein-DNA interactions, and co-immunoprecipitation (Co-IP) was used to examine protein-protein interactions.

RESULTS

CMTM4 expression in macrophages was upregulated in sepsis. The inhibition of CMTM4 expression reduced macrophage apoptosis. PD-L1 was identified as a key molecule regulated by CMTM4 in macrophage apoptosis. CMTM4 regulates PD-L1 by promoting the phosphorylation of its transcription factor, STAT2, rather than directly binding to PD-L1.

CONCLUSION

In sepsis, CMTM4 facilitates PD-L1-dependent macrophage apoptosis by enhancing STAT2 phosphorylation. This discovery offers new insights for the diagnosis and treatment of sepsis.

Practical microenvironment classification in diffuse large B cell lymphoma using digital pathology

Diffuse large B cell lymphoma (DLBCL) is a heterogeneous B cell neoplasm with variable clinical outcomes influenced by both tumor-derived and lymphoma microenvironment (LME) alterations. A recent transcriptomic study identifies four DLBCL subtypes based on LME characteristics: germinal center (GC)-like, mesenchymal (MS), inflammatory (IN), and depleted (DP). However, integrating this classification into clinical practice remains challenging. Here, we utilize deconvolution methods to assess microenvironment component abundance, establishing an LME classification of DLBCL using immunohistochemistry markers and digital pathology based on CD3, CD8, CD68, PD-L1, and collagen. This staining-based algorithm demonstrates over 80% concordance with transcriptome-based classification. Single-cell sequencing confirms that the immune microenvironments distinguished by this algorithm align with transcriptomic profiles. Significant disparities in overall and progression-free survival are observed among LME subtypes following rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) or R-CHOP with targeted agents (R-CHOP-X) immunochemotherapy. LME subtypes differed from distinct immune escape mechanisms, highlighting specific immunotherapeutic targets and supporting application of this classification in future precision medicine trials.

Macrophage Polarization in Lung Diseases: From Mechanisms to Therapeutic Strategies

Macrophages are pivotal immune cells involved in maintaining immune homeostasis and defending against pathogens. They exhibit significant plasticity and heterogeneity, enabling polarization into pro-inflammatory M1 or anti-inflammatory M2 phenotypes in response to distinct microenvironmental cues. The process of macrophage polarization is tightly regulated by complex signaling pathways and transcriptional networks. This review explores the factors influencing macrophage polarization, the associated signaling pathways, and their roles in the pathogenesis of lung diseases, including fibrosis, cancer, and chronic inflammatory conditions. By summarizing recent advances, we aim to provide insights into the immunoregulatory functions of macrophages and their therapeutic potential. Based on our review, it is believed that targeting macrophage polarization emerges as a promising approach for developing effective treatments for lung diseases, balancing inflammation and repair while mitigating disease progression.

Shared and distinct peripheral blood immune cell landscape in MCTD, SLE, and pSS

BACKGROUND

Mixed connective tissue disease (MCTD) is a rare autoimmune disease, and little is known about its pathogenesis. Furthermore, MCTD, systemic lupus erythematosus (SLE), and primary Sjögren's syndrome (pSS) share many clinical, laboratory, and immunological manifestations. This overlap complicates early diagnosis and accurate treatment.

METHODS

The transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) from MCTD patients was performed using both bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq) for the first time. Additionally, we applied MCTD scRNA-seq data, along with datasets from SLE (GSE135779) and pSS (GSE157278) from the Gene Expression Omnibus database, to characterize and compare the similarities and heterogeneity among MCTD, SLE, and pSS.

RESULTS

We first resolved transcriptomic changes in peripheral blood immune cells of MCTD, and then revealed the shared and unique features among MCTD, SLE, and pSS. Analyses showed that the percentage of CD8+ effector T cells was increased, while mucosal-associated invariant T cells were decreased in all three diseases. Genes related to the 'interferon (IFN) γ response' and 'IFN α response' were significantly upregulated. SCENIC analysis revealed activation of STAT1 and IRF7 in disease states, targeting IFN-related genes. The IFN-II signaling network was notably elevated in all three diseases. Unique features of MCTD, SLE, and pSS were also identified.

CONCLUSION

We dissected the immune landscape of MCTD at single-cell resolution, providing new insights into the development of novel biomarkers and immunotherapies for MCTD. Furthermore, we offer insights into the transcriptomic similarities and heterogeneity across different autoimmune diseases, while highlighting prospective therapeutic targets.

Nuclear AGO2 supports influenza A virus replication through type-I interferon regulation

The role of Argonaute (AGO) proteins and the RNA interference (RNAi) machinery in mammalian antiviral response has been debated. Therefore, we set out to investigate how mammalian RNAi impacts influenza A virus (IAV) infection. We reveal that IAV infection triggers nuclear accumulation of AGO2, which is directly facilitated by p53 activation. Mechanistically, we show that IAV induces nuclear AGO2 targeting of TRIM71and type-I interferon-pathway genes for silencing. Accordingly, Tp53-/- mice do not accumulate nuclear AGO2 and demonstrate decreased susceptibility to IAV infection. Hence, the RNAi machinery is highjacked by the virus to evade the immune system and support viral replication. Furthermore, the FDA-approved drug, arsenic trioxide, prevents p53 nuclear translocation, increases interferon response and decreases viral replication in vitro and in a mouse model in vivo. Our data indicate that targeting the AGO2:p53-mediated silencing of innate immunity may offer a promising strategy to mitigate viral infections.

Human papillomavirus E2 proteins suppress innate antiviral signaling pathways

Human papillomavirus (HPV) is a major cause of cancers and benign lesions. High-risk (HR) types, including HPV16 and HPV18, are strongly implicated in cervical and other malignancies, while low-risk (LR) types, such as HPV11, are predominantly associated with benign conditions. Although the immune evasion of HPV oncoproteins E6 and E7 are extensively studied, the immunomodulatory functions of the E2 protein remain poorly underexplored. This study elucidates the role of HPV11 and HPV16 E2 proteins in modulating innate immune responses, focusing on their interaction with key innate antiviral signaling pathways. We demonstrate that HPV11 and HPV16 E2 proteins effectively suppress the activation of pivotal antiviral signaling pathways, including RIG-I/MDA5-MAVS, TLR3-TRIF, cGAS-STING, and JAK-STAT. Mechanistic analyses reveal that E2 proteins interact with the core components of type I interferon (IFN)-inducing pathways, inhibiting IRF3 phosphorylation and nuclear translocation, thereby attenuating IFN expression. Additionally, E2 disrupts the JAK-STAT signaling cascade by preventing the assembly of the ISGF3 complex, comprising STAT1, STAT2, and IRF9, ultimately inhibiting the transcription of interferon-stimulated genes (ISGs). These findings underscore the broader immunosuppressive role of HPV E2 proteins, complementing the well-established immune evasion mechanisms mediated by E6 and E7. This work advances our understanding of HPV-mediated immune evasion and positions the E2 protein as a promising target for therapeutic strategies aimed at augmenting antiviral immunity in HPV-associated diseases.

Type I IFN receptor blockade alleviates liver fibrosis through macrophage-derived STAT3 signaling

Liver macrophages play a role in the development of liver fibrosis progression via the regulation of inflammatory signaling. However, the precise mechanisms of macrophages contributing to liver fibrosis progression remain unclear. Using a preclinical model of CCl4-treated mice, we determined the composition of immune cells and the alteration of inflammatory gene expression. Our findings revealed a significant increase in liver macrophages, particularly those derived from infiltrating blood monocytes, in fibrotic mice. Moreover, the expression levels of type I IFN signature genes such as IFNα, IFNβ, ISG15, USP18, Ifi44, Ifit1, Ifit2, IRF3, and IRF7 were elevated in fibrotic mice. To determine the role of type I IFN signaling in liver fibrosis, we administered an IFNAR-1 antibody to block this pathway for 3 days prior to harvesting the liver. Notably, IFNAR-1 blockade reduced macrophage numbers compared to control mice and alleviated liver fibrosis in mice with increased hepatocyte proliferation and apoptosis. The ratio of P-STAT3/P-STAT1 in monocyte-derived macrophages was increased in the IFNAR-1 blockade group compared to fibrotic mice, and this was related to the appearance of M2 macrophage differentiation. Additionally, single-cell RNA-seq analysis indicated that IFNAR blockade affected inflammatory pathways involved in hepatocyte regeneration and fibrosis prevention. Taken together, IFNAR-1 blockade alleviates liver fibrosis progression by modulating macrophage inflammatory responses. These results provide insights for developing anti-fibrotic therapies against type I IFN signaling.

Sterile production of interferons in the thymus

T-cell central tolerance is controlled by thymocyte TCR recognition of self-peptides presented by thymic APCs. While thymic epithelial cells are essential for T-cell central tolerance, a variety of other traditional APCs also play critical roles in T-cell selection. Similar to how peripheral APCs require activation to become effective, thymic APCs also require activation to become tolerogenic. Recent studies have identified IFNs as an essential factor for the activation and generation of an optimally tolerogenic thymic environment. In this review, we focus on interferon (IFN) production within the thymus and its effects on thymic APCs and developing thymocytes. We also examine the importance of T-cell tolerance to IFN itself as well as to interferon-stimulated proteins generated during peripheral immune responses.

Chasing Virus Replication and Infection: PAMP-PRR Interaction Drives Type I Interferon Production, Which in Turn Activates ISG Expression and ISGylation

The innate immune response, particularly the interferon-mediated pathway, serves as the first line of defense against viral infections. During virus infection, viral pathogen-associated molecular patterns (PAMPs) are recognized by host pattern recognition receptors (PRRs), triggering downstream signaling pathways. This leads to the activation of transcription factors like IRF3, IRF7, and NF-κB, which translocate to the nucleus and induce the production of type I interferons (IFN-α and IFN-β). Once secreted, type I interferons bind to their receptors (IFNARs) on the surfaces of infected and neighboring cells, activating the JAK-STAT pathway. This results in the formation of the ISGF3 complex (composed of STAT1, STAT2, and IRF9), which translocates to the nucleus and drives the expression of interferon-stimulated genes (ISGs). Some ISGs exert antiviral effects by directly or indirectly blocking infection and replication. Among these ISGs, ISG15 plays a crucial role in the ISGylation process, a ubiquitin-like modification that tags viral and host proteins, regulating immune responses and inhibiting viral replication. However, viruses have evolved counteractive strategies to evade ISG15-mediated immunity and ISGylation. This review first outlines the PAMP-PRR-induced pathways leading to the production of cytokines and ISGs, followed by a summary of ISGylation's role in antiviral defense and viral evasion mechanisms targeting ISG15 and ISGYlation.

Interferon-I modulation and natural products: Unraveling mechanisms and therapeutic potential in severe COVID-19

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to pose a significant global public health threat, particularly to older adults, pregnant women, and individuals with underlying chronic conditions. Dysregulated immune responses to SARS-CoV-2 infection are believed to contribute to the progression of COVID-19 in severe cases. Previous studies indicates that a deficiency in type I interferon (IFN-I) immunity accounts for approximately 15 %-20 % of patients with severe pneumonia caused by COVID-19, highlighting the potential therapeutic importance of modulating IFN-I signals. Natural products and their derivatives, due to their structural diversity and novel scaffolds, play a crucial role in drug discovery. Some of these natural products targeting IFN-I have demonstrated applications in infectious diseases and inflammatory conditions. However, the immunomodulatory potential of IFN-I in critical COVID-19 pneumonia and the natural compounds regulating the related signal pathway remain not fully understood. In this review, we offer a comprehensive assessment of the association between IFN-I and severe COVID-19, exploring its mechanisms and integrating information on natural compounds effective for IFN-I regulation. Focusing on the primary targets of IFN-I, we also summarize the regulatory mechanisms of natural products, their impact on IFNs, and their therapeutic roles in viral infections. Collectively, by synthesizing these findings, our goal is to provide a valuable reference for future research and to inspire innovative treatment strategies for COVID-19.

Conserved chromatin regulators control the transcriptional immune response to intracellular pathogens in Caenorhabditis elegans

Robust transcriptional responses are critical for defense against infection. However, unrestrained immune responses can cause negative impacts such as damaging inflammation and slowed development. Here, we find that a class of transcriptional regulators previously associated with regulation of development in Caenorhabditis elegans, is also involved in repressing immune responses. Specifically, through forward genetics, we find that loss of lin-15B leads to constitutive expression of Intracellular Pathogen Response (IPR) genes. lin-15B encodes a transcriptional repressor with a conserved THAP domain that is associated with the DRM chromatin remodeling complex that regulates C. elegans development. We show that lin-15B mutants have increased resistance to natural intracellular pathogens, and the induction of IPR genes in lin-15B mutants relies on the MES-4 histone methyltransferase. We extend our analyses to other DRM and NuRD chromatin remodeling factors, as well as SUMOylation histone modifiers, showing that a broad range of chromatin-related factors can repress IPR gene expression. Altogether these findings suggest that conserved chromatin regulators may facilitate development in part by repressing damaging immune responses against intracellular pathogens.

EBV enhances immunotherapy sensitivity in intrahepatic cholangiocarcinoma through cGAS-STING pathway activation

BACKGROUND

The absence of representative Epstein-Barr virus-associated intrahepatic cholangiocarcinoma (EBVaICC) cell lines has limited our understanding of the molecular and immunological characteristics of this cancer subtype.

METHODS

We reviewed patients with metastatic cholangiocarcinoma at Sun Yat-sen University Cancer Center from January 2015 to August 2023. Among them, 22 patients with EBVaICC and 66 patients with non-EBVaICC who received anti-PD1 treatment were included. Additionally, 2 EBV-positive ICC cell lines, RBE-EBV and HuH28-EBV, were developed through cell-to-cell infection. Stable EBV infection and responsiveness to viral reactivation were confirmed. Transcriptomic and bioinformatics analyses were performed, and in vitro experiments examined the immune effects of EBV-positive ICC. Key immune-related genes and cytokines were validated by reverse transcription quantitative polymerase chain reaction and ELISA in cell lines and patient plasma samples.

RESULTS

In this study, we found that patients with EBVaICC showed enhanced immune responses and improved overall and progression-free survival compared to patients with non-EBVaICC. We first successfully established and validated 2 EBV-positive ICC cell lines (RBE-EBV and HuH28-EBV). These cell lines were confirmed for stable EBV infection and displayed responsiveness to viral reactivation, making them suitable for future studies. Transcriptomic analyses and in vitro studies revealed that EBV activated the cGAS-STING pathway, resulting in MHC-I upregulation and CXCL10 secretion in ICC cells, which collectively enhanced CD8+ T cell chemotaxis and cytotoxicity. Furthermore, ELISA analysis showed higher plasma levels of CXCL10 and IFN-γ in patients with EBVaICC, suggesting a potential role for EBV in enhancing immunotherapy sensitivity in this subtype.

CONCLUSIONS

The established EBV-positive ICC cell lines revealed enhanced immunogenicity driven by cGAS-STING pathway activation, providing valuable models for future research and insights into the mechanisms of improved immunotherapy sensitivity in EBVaICC.

The characterization of a novel IRF8-like homolog and its role in the immune modulation of the sea urchin Strongylocentrotus intermedius

Interferon regulatory factor (IRF) proteins, functioning as transcription factors, are essential for various animal species' innate immune defense and stress responses. However, further research is required to elucidate the roles of IRF in echinoderms. In this study, a new IRF gene (SiIRF8-like) was obtained from the sea urchin (Strongylocentrotus intermedius). The open reading frame for SiIRF8-like spanned 2004 bp and encoded a protein composed of 667 amino acids. Domain prediction analysis revealed a typical IRF domain at the N-terminus and an IRF3 domain at the C terminus of the SiIRF8-like protein, exhibiting similar amino acid sequences across different species. Phylogenetic analyses indicated that SiIRF8-like proteins were closely related to mollusk IRF8 proteins. Quantitative real-time PCR revealed detectable levels of SiIRF8-like mRNA in all sea urchin tissues examined, with the highest expression observed in coelomocytes. Furthermore, lipopolysaccharide and polyinosinic-polycytidylic acid treatments significantly increased transcript expression levels of SiIRF8-like. Subcellular localization experiments revealed that SiIRF8-like is mainly localized in the nucleus. Additionally, dual-luciferase reporter assays indicated that overexpression of SiIRF8-like in HEK293T cells could specifically activate reporter genes such as interleukin 6, interferon α/β/γ, activating protein 1, and interferon-stimulated response element. Finally, the overexpressed SiIRF8-like could promote the phosphorylation of protein kinases (JNK and Erk1/2). These preliminary findings regarding the immune functions linked to the SiIRF8-like protein offer valuable insights into the innate immunity mechanisms of invertebrate IRFs and provide theoretical support for developing disease-resistant strains of sea urchins.

Toward a personalized therapy of still's disease based on immunologic endotypes: a narrative review

INTRODUCTION

Accumulative evidence indicates that both innate and adaptive immunity are involved in pathogenesis of Still's disease, an autoinflammatory disease. With Increasing insights into the pathogenesis of Still's disease coupled with the availability of emerging targeted therapeutics, it may be the unmet need for personalizing therapy and achieving a treat-to-target goal. We aim to summarize the available evidence regarding immunopathogenesis of Still's disease and therapeutic strategies based on immunologic endotypes.

AREAS COVERED

We searched MEDLINE database using the PubMed interface and reviewed relevant English-language literature from 1971 to 2024. This review focuses on the existing evidence on pathophysiology and immunological endotypes of Still's disease and their implications for personalized strategies for patients with this disease.

EXPERT OPINION

Targeting the complex immunopathogenesis of Still's disease, emerging new agents are available for treatment, including biologic disease-modifying anti-rheumatic drugs (bDMARDs) and targeted synthetic DMARDs (tsDMARDs) such as Janus kinase inhibitors (JAKi). According to the updated evidence, meta-analyses, and recommendations, we propose a flow chart emphasizing personalized therapeutic strategies based on immunological endotypes. Hopefully, the therapeutic strategy might help guide the optimal selection of b/tsDMARDs to achieve a 'treat-to-target' goal in Still's disease. This proposed flow chart will be updated as newer evidence emerges.

Guardians at the gate: Unraveling Type I interferon's role and challenges posed by anti-interferon antibodies in COVID-19

The intricate interplay involving Type I interferon (IFN), anti-interferon antibodies, and COVID-19 elucidates a complex symphony within the immune system. This chapter thoroughly explores the dynamic landscape of Type I IFN, delineating its pivotal role as the guardian of the immune response. As SARS-CoV-2 engages the host, the delicate balance of IFN induction and signaling pathways is disrupted, resulting in a nuanced impact on the severity and pathogenesis of COVID-19. Clinical studies illuminate a critical link between impaired IFN response and severe outcomes, uncovering genetic factors contributing to susceptibility. Furthermore, the emergence of anti-interferon antibodies proves to be a disruptive force, compromising the immune arsenal and correlating with disease severity. Our chapter encompasses diagnostic and prognostic implications, highlighting the importance of assays in identifying levels of IFN and anti-interferon antibodies. This chapter examines the possible incorporation of interferon-related biomarkers in COVID-19 diagnostics, offering predictive insights into disease progression. On the therapeutic front, efforts to manipulate the IFN pathway undergo scrutiny, encountering complexities in light of anti-interferon antibodies. This chapter concludes by outlining prospective avenues for precision medicine, emphasizing the imperative need for a comprehensive comprehension of the IFN landscape and its intricate interaction with COVID-19.

The alpha-coronavirus E protein inhibits the JAK-STAT pathway signaling by triggering STAT2 degradation through OPTN- and NBR1-mediated selective autophagy

The zoonotic transmission of coronaviruses continues to pose a considerable threat to humans. Swine acute diarrhea syndrome coronavirus (SADS-CoV), a bat coronavirus related to HKU2, causes severe economic losses in the pig industry and has the potential to trigger outbreaks in humans. However, our understanding of how SADS-CoV evades the host's innate immunity remains limited, hindering effective responses to potential human outbreaks. In this study, we demonstrate that the SADS-CoV envelope protein (E) inhibits type I interferon (IFN-I) signaling by inducing the degradation of STAT2 via the macroautophagy/autophagy-lysosome pathway. Mechanistically, the E protein evades host innate immunity by promoting STAT2 degradation through autophagy, mediated by the NBR1 and OPTN receptors. Notably, ubiquitination of E protein is required for the autophagic degradation of STAT2. Additionally, lysine residue K61 of the E protein is crucial for its stable expression; however, it is not involved in its ubiquitination. In conclusion, our study reveals a novel mechanism by which the E protein disrupts IFN-I signaling by targeting STAT2 via autophagy, enhancing our understanding of SADS-CoV's immune evasion strategies and providing potential drug targets for controlling viral infections.Abbreviations: 3-MA: 3-methyladenine; ATG: autophagy related; BafA1: bafilomycin A1; BSA: bovine serum albumin; CALCOCO2/NDP52: calcium binding and coiled-coil domain 2; CC: coiled-coil; CHX: cycloheximide; Co-IP: co-immunoprecipitation; DAPI: 4',6-diamidino-2-phenylindole; DBD: DNA-binding domain; DMEM: Dulbecco's Modified Eagle's medium; DMSO: dimethyl sulfoxide; E, Envelope. FW: four-tryptophan; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; HA: hemagglutinin; hpt: hours post-treatment; IF: indirect immunofluorescence; IFNB/IFN-β: interferon beta; IgG: immunoglobulin G; ISG: IFN-stimulated genes; ISRE: interferon-stimulated response element; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MOI: multiplicity of infection; NBR1: NBR1 autophagy cargo receptor; OPTN: optineurin; PBS: phosphate-buffered saline; PRRs: pattern recognition receptors; qPCR: quantitative polymerase chain reaction; SAR: selective autophagy receptor; SQSTM1/p62: sequestosome 1; STAT: signal transduction and activator of transcription; TBS-T: Tris-buffered saline with Tween 20; TCID50: 50% tissue culture infective dose; TOLLIP: toll interacting protein; Ub: ubiquitin; UBA: C-terminal ubiquitin-associated; VSV: vesicular stomatitis virus; WB: western blotting. WT: wild type.

Blood Single-Cell Transcriptomic and Proteomic Signatures of Paradoxical Eczema in Patients with Psoriasis Treated with Biologics

Biologics targeting the TNF and IL-17/23 axis are highly effective treatments for psoriasis but can result in cutaneous adverse events. The pathogenesis of paradoxical eczema, the occurrence of an atopic dermatitis phenotype after biologic initiation in people with psoriasis, is unknown. Using single-cell RNA sequencing and mass cytometry, we found increased expression of TNF, IFN-γ, and IFN-α and their signaling pathways in paradoxical eczema case cell clusters compared with that in matched psoriasis controls. Genetic variants influencing the expression of chemokine signaling and TNF pathway genes were associated with paradoxical eczema in a separate genotyped cohort, and this association was independent of known atopic risk loci. This suggests that paradoxical eczema has a predominantly type 1 systemic inflammatory signature and that genetic susceptibility to aberrant chemokine and TNF pathway signaling could contribute to development of this phenotype during biologic treatment.

STAT Signature Dish: Serving Immunity with a Side of Dietary Control

Immunity is a fundamental aspect of animal biology, defined as the host's ability to detect and defend against harmful pathogens and toxic substances to preserve homeostasis. However, immune defenses are metabolically demanding, requiring the efficient allocation of limited resources to balance immune function with other physiological and developmental needs. To achieve this balance, organisms have evolved sophisticated signaling networks that enable precise, context-specific responses to internal and external cues. These networks are essential for survival and adaptation in multicellular systems. Central to this regulatory architecture is the STAT (signal transducer and activator of Transcription) family, a group of versatile signaling molecules that govern a wide array of biological processes across eukaryotes. STAT signaling demonstrates remarkable plasticity, from orchestrating host defense mechanisms to regulating dietary metabolism. Despite its critical role, the cell-specific and context-dependent nuances of STAT signaling remain incompletely understood, highlighting a significant gap in our understanding. This review delves into emerging perspectives on immunity, presenting dynamic frameworks to explore the complexity and adaptability of STAT signaling and the underlying logic driving cellular decision-making. It emphasizes how STAT pathways integrate diverse physiological processes, from immune responses to dietary regulation, ultimately supporting organismal balance and homeostasis.

Regulation of immunogenic cell death and potential applications in cancer therapy

Immunogenic cell death (ICD), a type of regulatory cell death, plays an important role in activating the adaptive immune response. Activation of the tumor-specific immune response is accompanied by the cell surface exposure of calreticulin and heat-shock proteins, the secretion of adenosine triphosphate, and the release of high mobility group box-1. In this review, we summarize and classify the latest types of ICD inducers and their molecular mechanisms, and discuss the effects and potential applications of inducing ICD by chemotherapy drugs, targeted drugs, and oncolytic viruses in clinical research. We also explore the potential role of epigenetic modifiers in the induction of ICD, and clarify the synergistic anti-tumor effects of nano-pulse stimulation, radiosensitizers for radiotherapy, photosensitizers for photodynamic therapy, photothermal therapy, and other physical stimulation, combined with radiotherapy and chemotherapy induced-ICD, in multimodal immunotherapy. In addition, we elucidate the molecular mechanism of ICD in detail, including the calcium imbalance, mitochondrial stress, and the interactions in the tumor microenvironment. Ultimately, this review aims to offer deeper insight into the factors and mechanisms of ICD induction and provide a theoretical basis for the future development of ICD-based immunotherapy.

Host restriction factors against porcine epidemic diarrhea virus: a mini-review

Porcine epidemic diarrhea is an acute contagious disease caused by porcine epidemic diarrhea virus (PEDV), which severely constrains the development of the global swine industry. Host restriction factors constitute a vital defensive barrier against viral infections, typically interacting with viruses at specific stages of their replication process to disrupt it. Considering that traditional PEDV vaccines often struggle to effectively activate mucosal immunity in sows and thereby fail to provide reliable passive immunity to piglets via milk, this review focuses on the host restriction factors that play crucial roles in restricting PEDV infection and replication. The aim is to identify potential targets for the development of anti-PEDV drugs and offer insights for the exploration of novel vaccine adjuvants.

Distinct pathogenic mutations in ARF1 allow dissection of its dual role in cGAS-STING signalling

Tight control of cGAS-STING-mediated DNA sensing is crucial to avoid auto-inflammation. The GTPase ADP-ribosylation factor 1 (ARF1) is crucial to maintain cGAS-STING homeostasis and various pathogenic ARF1 variants are associated with type I interferonopathies. Functional ARF1 inhibits STING activity by maintaining mitochondrial integrity and facilitating COPI-mediated retrograde STING trafficking and deactivation. Yet the factors governing the two distinct functions of ARF1 remained unexplored. Here, we dissect ARF1's dual role by a comparative analysis of disease-associated ARF1 variants and their impact on STING signalling. We identify a de novo heterozygous s.55 C > T/p.R19C ARF1 variant in a patient with type I interferonopathy symptoms. The GTPase-deficient variant ARF1 R19C selectively disrupts COPI binding and retrograde transport of STING, thereby prolonging innate immune activation without affecting mitochondrial integrity. Treatment of patient fibroblasts in vitro with the STING signalling inhibitors H-151 and amlexanox reduces chronic interferon signalling. Summarizing, our data reveal the molecular basis of a ARF1-associated type I interferonopathy allowing dissection of the two roles of ARF1, and suggest that pharmacological targeting of STING may alleviate ARF1-associated auto-inflammation.

Validation of Polymorphisms Associated with the Immune Response After Vaccination Against Porcine Reproductive and Respiratory Syndrome Virus in Yorkshire Gilts

Porcine respiratory and reproductive syndrome is a viral disease that impacts the health and profitability of swine farms, largely due to significant variation in the vaccination response. The objective was to identify and validate molecular markers associated with the antibody response in gilts following vaccination against the PRRSV. The study included one hundred (n = 100) 6-month-old Yorkshire gilts that were negative for the PRRSV. Gilts were randomly assigned to one of two treatments, PRRS-vaccinated (n = 75) and control (n = 25) groups. Blood samples collected on day 21 were analyzed to evaluate the antibody response, as indicated by the sample-to-positive (S/P) ratio, to the PRRSV following vaccination. DNA was extracted and genotyped using a low-density chip containing 10,000 single nucleotide polymorphisms (SNPs). A genome-wide association study (GWAS) was conducted to identify candidate SNPs associated with the S/P ratio, which were validated in two independent gilt populations (n = 226). The SNPs rs707264998, rs708860811, and rs81358818 in the genes RNF144B, XKR9, and BMAL1, respectively, were significantly associated (p < 0.01) with the S/P ratio and demonstrated an additive effect. In conclusion, three SNPs are proposed as candidate markers for an enhanced immune response to vaccination against the PRRSV and may be beneficial in genetic selection programs.

Nailfold videocapillaroscopy findings are associated with IIM subtypes and IFN activation

OBJECTIVE

This study aimed to characterize nailfold videocapillaroscopy (NVC) features in patients with different subtypes of Idiopathic inflammatory myopathy (IIM) and to investigate the correlations between NVC findings, myositis-specific antibody (MSA) subtypes, disease activity, cytokine profiles, and interferon-stimulated gene (ISG) expression levels.

METHODS

This cross-sectional observational single-center study included 55 IIM patients, categorized into MDA5 (+), anti-aminoacyl-tRNA-synthetase antibodies (ARS) (+), and MSA(-) groups based on their MSA profiles. Demographic data, laboratory tests, and NVC assessments were systematically collected and analyzed. The relative expression of type I ISGs in whole blood, as well as serum cytokine and chemokine profiles, were measured. Statistical analyses were performed to explore correlations between NVC scores and clinical parameters, including serum biomarkers.

RESULTS

NVC abnormalities were observed in most IIM patients, with significant differences in NVC features among the MSA subgroups. The MDA5(+) group exhibited significantly higher scores for capillary dilation (P < 0.01), giant capillaries (P < 0.05), microhemorrhages (P < 0.01), and abnormal capillary morphology (P < 0.05) compared to the ARS (+) group. ISG expression and cytokine levels were upregulated in IIM patients, with active disease patients showing significantly higher levels of certain ISGs and cytokines compared to clinically stable patients. Notably, specific NVC score dimensions were positively correlated with the levels of certain ISGs and cytokines. For example, microhemorrhage, capillary dilation, and capillary density all had significantly positive correlations with MX1, IFI27, IP-10, RANTES, and GROα (P < 0.05). And giant capillary is also related to levels of IFI27, SDF-1α, IP-10, RANTES, and GROα (P < 0.05).

CONCLUSION

IIM patients exhibit distinct NVC abnormalities, which vary across different MSA subtypes. NVC findings have potential clinical value in screening disease activity and interferon pathway activation in IIM patients.

Antiviral Therapy-Induced Changes in Long Non-Coding RNA Expression Profiles in Umbilical Cord Blood and Placental Tissues of Hepatitis B Virus-Infected Pregnant Women

Background

Hepatitis B virus (HBV) is a major global health concern, with maternal-fetal transmission being the primary route of transmission, which can lead to chronic HBV infection in newborns. Long non-coding RNAs (lncRNAs) play crucial roles in gene regulation and immune responses, but their involvement in HBV transmission during pregnancy remains unclear. This study aimed to assess the impact of tenofovir disoproxil fumarate (TDF)-based antiviral therapy on lncRNA expression profiles and immune signaling pathways in umbilical cord blood and placental tissues and to identify potential therapeutic targets for preventing intrauterine HBV infection.

Materials and Methods

Umbilical cord serum and placental tissues were collected from six HBV carriers. Three carriers received TDF-based antiviral therapy, and the remaining carriers who did not receive antiviral therapy served as controls. LncRNA microarray analysis and bioinformatics were used to evaluate the effects of antiviral therapy on lncRNA expression profiles and signaling pathways.

Results

Antiviral therapy exerted minimal effects on lncRNA expression profiles in umbilical cord blood. In placental tissues, significant alterations in lncRNA expression profiles were observed, including 249 upregulated and 381 downregulated lncRNAs. Antiviral therapy activated innate immune pathways, such as intracellular DNA sensing, chemokine signaling, type I interferon, Jak-Stat, and interferon-γ-mediated adaptive immunity. Through intersection analysis, CPED1 was found differentially expressed in both cord blood and placental tissues. KEGG pathway analysis suggested that low CPED1 expression may inhibit virus transmission via the JAK-STAT pathway.

Conclusion

This study demonstrated that TDF-based antiviral therapy altered lncRNA expression and activated immune signaling pathways in placental tissues, offering insights into the molecular mechanisms of maternal-fetal HBV transmission.

Potential role of lactylation in intrinsic immune pathways in lung cancer

Lung cancer, one of the most lethal malignancies, has seen its therapeutic strategies become a focal point of significant scientific attention. Intrinsic immune signaling pathways play crucial roles in anti-tumor immunity but face clinical application challenges despite promising preclinical outcomes. Lactylation, an emerging research focus, may influences lung cancer progression by modulating the functions of histones and non-histone proteins. Recent findings have suggested that lactylation regulates key intrinsic immune molecules, including cGAS-STING, TLR, and RIG-I, thereby impacting interferon expression. However, the precise mechanisms by which lactylation governs intrinsic immune signaling in lung cancer remain unclear. This review presents a comprehensive and systematic analysis of the relationship between lactylation and intrinsic immune signaling pathways in lung cancer and emphasizes the innovative perspective of linking lactylation-mediated epigenetic modifications with immune regulation. By thoroughly examining current research findings, this review uncovers potential regulatory mechanisms and highlights the therapeutic implications of targeting lactylation in lung cancer. Future investigations into the intricate interactions between lactylation and intrinsic immunity are anticipated to unveil novel therapeutic targets and strategies, potentially improving patient survival outcomes.

Altered LY6E and TRIM6 expression in PBMCs correlated with HBsAg clearance and response to Peg-IFN-α treatment in HBeAg-negative chronic hepatitis B patients

BACKGROUND

Pegylated interferon alpha (Peg-IFN-α) has the potential to eradicate hepatitis B surface antigen (HBsAg). This study aimed to investigate whether the expression levels of lymphocyte antigen 6 family member E (LY6E) and tripartite motif-containing protein 6 (TRIM6) mRNAs in peripheral blood mononuclear cells (PBMCs) of hepatitis B e antigen (HBeAg)-negative chronic hepatitis B virus (HBV) patients is associated with the response to Peg-IFN-α treatment and HBsAg clearance.

METHODS

In this prospective study, HBeAg-negative chronic HBV patients treated with Peg-IFN-α were followed for 48 weeks. The participants were classified into two groups, the virological response (VR) group and nonvirological response (NVR) group, according to the changes in HBV DNA and HBsAg levels observed at week 48 of treatment. Furthermore, these patients were divided into a serological response (SR) group and a nonserological response (NSR) group, depending on whether they exhibited a loss of serum HBsAg or evidence of seroconversion. The expression levels of LY6E and TRIM6 mRNAs in PBMCs were evaluated using real-time quantitative PCR with fluorescence detection. The diagnostic performance of LY6E and TRIM6 was assessed by analyzing the receiver operating characteristic (ROC) curve and calculating the area under the ROC curve (AUC).

RESULTS

After the treatment period, the observed VR and SR rates were 44.64% and 28.57%, respectively. Dynamic changes in LY6E and TRIM6 mRNA levels were significantly different between the VR and NVR groups and between the SR and NSR groups. Multivariate analysis revealed that TRIM6 was independently associated with VR at weeks 12 and 24 of Peg-IFN-α therapy and with SR at week 12; in addition, LY6E was independently associated with VR at week 12 and SR at week 24. At week 24, the area under the curve (AUC) for LY6E in the prediction of VR was 0.6942, and the AUC for the prediction of SR was 0.7766; at week 12, TRIM6 had AUCs of 0.7600 for the prediction of VR and 0.8469 for the prediction of SR.

CONCLUSIONS

LY6E and TRIM6 are important biomarkers for early therapeutic responses to Peg-IFN-α and HBsAg clearance.

TRIAL REGISTRATION

Registration number: 2023 - 311. Date of registration: 1 October 2023.

Mild Zika Virus Infection in Mice Without Motor Impairments Induces Working Memory Deficits, Anxiety-like Behaviors, and Dysregulation of Immunity and Synaptic Vesicle Pathways

BACKGROUND

The Zika virus (ZIKV) is an arbovirus linked to "Congenital Zika Syndrome" and a range of neurodevelopmental disorders (NDDs), with microcephaly as the most severe manifestation. Milder NDDs, such as autism spectrum disorders and delays in neuropsychomotor and language development, often go unnoticed in neonates, resulting in long-term social and academic difficulties. Murine models of ZIKV infection can be used to mimic part of the spectrum of motor and cognitive deficits observed in humans. These can be evaluated through behavioral tests, enabling comparison with gene expression profiles and aiding in the characterization of ZIKV-induced NDDs.

OBJECTIVES

This study aimed to identify genes associated with behavioral changes following a subtle ZIKV infection in juvenile BALB/c mice.

METHODS

Neonatal mice were subcutaneously inoculated with ZIKV (MH544701.2) on postnatal day 1 (DPN) at a dose of 6.8 × 103 PFU. Viral presence in the cerebellum and cortex was quantified at 10- and 30-days post-infection (DPI) using RT-qPCR. Neurobehavioral deficits were assessed at 30 DPI through T-maze, rotarod, and open field tests. Next-Generation Sequencing (NGS) was performed to identify differentially expressed genes (DEGs), which were analyzed through Gene Ontology (GO) and KEGG enrichment. Gene interaction networks were then constructed to explore gene interactions in the most enriched biological categories.

RESULTS

A ZIKV infection model was successfully established, enabling brain infection while allowing survival beyond 30 DPI. The infection induced mild cognitive behavioral changes, though motor and motivational functions remained unaffected. These cognitive changes were linked to the functional repression of synaptic vesicles and alterations in neuronal structure, suggesting potential disruptions in neuronal plasticity.

CONCLUSIONS

Moderate ZIKV infection with circulating strains from the 2016 epidemic may cause dysregulation of genes related to immune response, alterations in cytoskeletal organization, and modifications in cellular transport mediated by vesicles. Despite viral control, neurocognitive effects persisted, including memory deficits and anxiety-like behaviors, highlighting the long-term neurological consequences of ZIKV infection in models that show no apparent malformations.