Search

In Finland, the frequency of isolated cleft palate (CP) is higher than that of isolated cleft lip with or without cleft palate (CL/P). This trend contrasts to that in other European countries but its genetic underpinnings are unknown. We conducted a genome-wide association study in the Finnish population and identified rs570516915, a single nucleotide polymorphism highly enriched in Finns, as strongly associated with CP (P = 5.25 × 10-34, OR = 8.65, 95% CI 6.11-12.25), but not with CL/P (P = 7.2 × 10-5), with genome-wide significance. The risk allele frequency of rs570516915 parallels the regional variation of CP prevalence in Finland, and the association was replicated in independent cohorts of CP cases from Finland (P = 8.82 × 10-28) and Estonia (P = 1.25 × 10-5). The risk allele of rs570516915 alters a conserved binding site for the transcription factor IRF6 within an enhancer (MCS-9.7) upstream of the IRF6 gene and diminishes the enhancer activity. Oral epithelial cells derived from CRISPR-Cas9 edited induced pluripotent stem cells demonstrate that the CP-associated allele of rs570516915 concomitantly decreases the binding of IRF6 and the expression level of IRF6, suggesting impaired IRF6 autoregulation as a molecular mechanism underlying the risk for CP.

Enhancers control the location and timing of gene expression and contain the majority of variants associated with disease1-3. The ZRS is arguably the most well-studied vertebrate enhancer and mediates the expression of Shh in the developing limb4. Thirty-one human single-nucleotide variants (SNVs) within the ZRS are associated with polydactyly4-6. However, how this enhancer encodes tissue-specific activity, and the mechanisms by which SNVs alter the number of digits, are poorly understood. Here we show that the ETS sites within the ZRS are low affinity, and identify a functional ETS site, ETS-A, with extremely low affinity. Two human SNVs and a synthetic variant optimize the binding affinity of ETS-A subtly from 15% to around 25% relative to the strongest ETS binding sequence, and cause polydactyly with the same penetrance and severity. A greater increase in affinity results in phenotypes that are more penetrant and more severe. Affinity-optimizing SNVs in other ETS sites in the ZRS, as well as in ETS, interferon regulatory factor (IRF), HOX and activator protein 1 (AP-1) sites within a wide variety of enhancers, cause gain-of-function gene expression. The prevalence of binding sites with suboptimal affinity in enhancers creates a vulnerability in genomes whereby SNVs that optimize affinity, even slightly, can be pathogenic. Searching for affinity-optimizing SNVs in genomes could provide a mechanistic approach to identify causal variants that underlie enhanceropathies.

Background: TANK-binding kinase 1 (TBK1) is a pivotal mediator of innate immunity, activated by receptors such as mitochondrial antiviral signaling protein (MAVS), stimulator of interferon genes (STING), and TIR-domain-containing adaptor inducing interferon-β (TRIF). It modulates immune responses by exerting influence on the type I interferons (IFN-Is) signaling and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways, Over the past few years, TBK1 multifaceted role in both immune and inflammatory responses is increasingly recognized. Methods and Results: This review aims to scrutinize how TBK1 operates within the NF-κB pathway and the interferon regulatory transcription factor 3 (IRF3)-dependent IFN-I pathways, highlighting the kinases and other molecules involved in these processes. This analysis reveals the distinctive characteristics of TBK1's involvement in these pathways. Furthermore, it has been observed that the role of TBK1 in exerting anti-inflammatory or pro-inflammatory effects is contingent upon varying pathological conditions, indicating a multifaceted role in immune regulation. Discussion: TBK1's evolving role in various diseases and the potential of TBK1 inhibitors as therapeutic agents are explored. Targeting TBK1 may provide new strategies for treating inflammatory disorders and autoimmune diseases associated with IFN-Is, warranting further investigation. [ABSTRACT FROM AUTHOR]

T cell dysfunction is a major barrier to more effective and long-lasting treatment responses in cancer. Transcription factors (TFs), including nuclear factor of activated T cells (NFAT)/activating protein-1 (AP-1), interferon regulatory factor 4 (IRF4)/basic leucine zipper ATF-like TF (BATF), T cell factor 1 (TCF-1), NR4A, TOX, and T-bet/Eomes, play critical context-specific roles in T cell development, function, and dysfunction. Targeting TFs with existing and future small molecule modulators is an untapped therapeutic opportunity to overcome T cell dysfunction. Small molecule modulators may be able to fine-tune TF protein–protein interactions and activity to prevent exhaustion while preserving critical T cell differentiation, effector, and memory programs. Immune checkpoint blockade (ICB) therapies, which block inhibitory receptors on T cells, can be efficacious in reinvigorating dysfunctional T cell responses. However, most cancers do not respond to these therapies and even in those that respond, tumors can acquire resistance. New strategies are needed to rescue and recruit T cell responses across patient populations and disease states. In this review, we define mechanisms of T cell dysfunction, focusing on key transcription factor (TF) networks. We discuss the complex and sometimes contradictory roles of core TFs in both T cell function and dysfunction. Finally, we review strategies to target TFs using small molecule modulators, which represent a challenging but highly promising opportunity to tune the T cell response toward sustained immunity. [ABSTRACT FROM AUTHOR]

Sepsis‐induced acute lung injury (ALI) is characterized by inflammatory damage to pulmonary endothelial and epithelial cells. The aim of this study is to probe the significance and mechanism of tripartite motif‐containing protein 21 (TRIM21) in sepsis‐induced ALI. The sepsis‐induced ALI mouse model was established by cecum ligation and puncture. The mice were infected with lentivirus and treated with proteasome inhibitor MG132. The lung respiratory damage, levels of interleukin‐6 (IL‐6), tumour necrosis factor α (TNF‐α), IL‐10 and pathological changes were observed. The expression levels of TRIM21, interferon regulatory factors 1 (IRF1) and triggering receptor expressed on myeloid cells 2 (TREM2) were measured and their interactions were analysed. The ubiquitination level of IRF1 was detected. TRIM21 and TREM2 were downregulated and IRF1 was upregulated in sepsis‐induced ALI mice. TRIM21 overexpression eased inflammation and lung injury. TRIM21 promoted IRF1 degradation via ubiquitination modification. IRF1 bonded to the TREM2 promoter to inhibit its transcription. Overexpression of IRF1 or silencing TREM2 reversed the improvement of TRIM21 overexpression on lung injury in mice. In conclusion, TRIM21 reduced IRF1 expression by ubiquitination to improve TREM2 expression and ameliorate sepsis‐induced ALI. [ABSTRACT FROM AUTHOR]

Loss-of-function mutations in nucleotide-binding oligomerization domain 2 (NOD2) constitute the primary risk factors for Crohn’s disease. NOD2 is an intracellular sensor for muramyl dipeptide (MDP), a small molecule derived from the peptidoglycan layer of bacterial cell wall. Although NOD2 is involved in host immune responses, much attention has been paid to the involvement of NOD2 in the maintenance of intestinal homeostasis. Despite the fact that the proinflammatory cytokine and chemokine responses induced by NOD2 activation alone are weaker than those induced by toll-like receptors (TLRs), NOD2 plays a crucial role in host defense against invading pathogens and in the regulation of immune responses. Recent studies have highlighted the importance of negative regulatory functions of NOD2 in TLRs-mediated proinflammatory cytokine responses. MDP-mediated activation of NOD2 induces interferon regulatory factor 4 (IRF4) expression, thereby suppressing nuclear factor-kB-dependent colitogenic cytokine responses through the inhibition of Lys(K)63-linked polyubiquitination on receptor-interacting serine/ threonine protein kinase 2. MDP-mediated activation of NOD2 also downregulates TLR9-induced type I IFN responses by inhibiting the K63-linked polyubiquitination of TNF receptor-associated factor 3 via deubiquitinating enzyme A (DUBA) expression. Thus, NOD2 exerts dual negative regulation of TLRs-mediated proinflammatory cytokine and type I IFN responses by inducing the expression of IRF4 and DUBA, respectively. In this review, we summarize the molecular mechanisms whereby NOD2 activation suppresses TLRs-mediated proinflammatory and type I IFN responses. In addition, we discuss the clinical relevance of the NOD2-mediated negative regulation of TLRs in inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

BackgroundMethodsResultsConclusionAllergic asthma is characterized by airway hyperresponsiveness triggered by inhaled allergens. Type 2 innate lymphoid cells (ILC2s) have been demonstrated to play a crucial role in promoting airway inflammation through the secretion of type 2 effector cytokines. However, the mechanisms underlying the functions of lung ILC2s remain unclear.In this study, we investigated the expression of IRF3 in ILC2s in both human patients and mouse models of asthma. We utilized IRF3-deficient mice to assess the impact of IRF3 deficiency on ILC2 function in a model of IL33-induced asthma. Additionally, we explored the mechanisms underlying IRF3-mediated regulation of ILC2s, focusing on the involvement of the transcription factor Gata3.Our findings revealed elevated expression of IRF3 in ILC2s of patients and mice with asthma, suggesting a potential role for IRF3 in the pathogenesis of allergic asthma. Furthermore, we demonstrated that IRF3 deficiency impairedthe expansion and function of ILC2s in IL33-induced asthma, highlighting the importance of IRF3 in regulating ILC2-mediated responses. Importantly, we showed that the regulation of ILC2s by IRF3 was independent of Th2 cells and mediated by the transcription factor Gata3.This study identifies IRF3 as a novel regulator of lung ILC2s and suggests its potential as a promising immunotherapeutic target for allergic asthma. These findings shed light on the intricate mechanisms underlying asthma pathogenesis and provide insights into potential strategies for the development of targeted therapies for this prevalent airway disease. [ABSTRACT FROM AUTHOR]

Osteoarthritis (OA) is an age-related cartilage-degenerating joint disease. Mitochondrial dysfunction has been reported to promote the development of OA. Poly (ADP-ribose) polymerase family member 12 (PARP12) is a key regulator of mitochondrial function, protein translation, and inflammation. However, the role of PARP12 in OA-based cartilage degradation and the underlying mechanisms are relatively unknown. Here, we first demonstrated that PARP12 inhibits mitophagy and promotes OA progression in human OA cartilage and a monosodium iodoacetate-induced rat OA model. Using mass spectrometry and co-immunoprecipitation assay, PARP12 was shown to interact with ISG15, upregulate mitofusin 1 and 2 (MFN1/2) ISGylation, which downregulated MFN1/2 ubiquitination and SUMOylation, thereby inhibiting PINK1/Parkin-dependent chondrocyte mitophagy and promoting cartilage degradation. Moreover, inflammatory cytokine-induced interferon regulatory factor 1 (IRF1) activation was required for the upregulation of PARP12 expression, and it directly bound to the PARP12 promoter to activate transcription. XAV-939 inhibited PARP12 expression and suppressed OA pathogenesis in vitro and in vivo. Clinically, PARP12 can be used to predict the severity of OA; thus, it represents a new target for the study of mitophagy and OA progression. In brief, the IRF1-mediated upregulation of PARP12 promoted cartilage degradation by inhibiting PINK1/Parkin-dependent mitophagy via ISG15-based attenuation of MFN1/2 ubiquitylation and SUMOylation. Our data provide new insights into the molecular mechanisms underlying PARP12-based regulation of mitophagy and can facilitate the development of therapeutic strategies for the treatment of OA. [ABSTRACT FROM AUTHOR]

The specific mechanisms underlying bacteria‐triggered cell death and osteogenic dysfunction in host bone marrow mesenchymal stem cells (BMSCs) remain unclear, posing a significant challenge to the repair of infected bone defects. This study identifies ferroptosis as the predominant cause of BMSCs death in the infected bone microenvironment. Mechanistically, the bacteria‐induced activation of the innate immune response in BMSCs leads to upregulation and phosphorylation of interferon regulatory factor 7 (IRF7), thus facilitating IRF7‐dependent ferroptosis of BMSCs through the transcriptional upregulation of acyl‐coenzyme A synthetase long‐chain family member 4 (ACSL4). Moreover, it is found that intervening in ferroptosis can partially rescue cell injuries and osteogenic dysfunction. Based on these findings, a hydrogel composite 3D‐printed scaffold is designed with reactive oxygen species (ROS)‐responsive release of antibacterial quaternized chitosan and sustained delivery of the ferroptosis inhibitor Ferrostatin‐1 (Fer‐1), capable of eradicating pathogens and promoting bone regeneration in a rat model of infected bone defects. Together, this study suggests that ferroptosis of BMSCs is a promising therapeutic target for infected bone defect repair. [ABSTRACT FROM AUTHOR]

The treatment of pancreatic ductal adenocarcinoma (PDAC) is an unmet challenge, with the median overall survival rate remaining less than a year, even with the use of FOLFIRINOX-based therapies. This study analyzed archived macrophage-associated mRNA expression using datasets deposited in the UCSC Xena web platform to compare normal pancreatic tissue and PDAC tumor samples. The TGFB2 gene exhibited low mRNA expression levels in normal tissue, with less than one TPM. In contrast, in tumor tissue, TGFB2 expression levels exhibited a 7.9-fold increase in mRNA expression relative to normal tissue (p < 0.0001). Additionally, components of the type-I interferon signaling pathway exhibited significant upregulation of mRNA levels in tumor tissue, including Interferon alpha/beta receptor 1 (IFNAR1; 3.4-fold increase, p < 0.0001), Interferon regulatory factor 9 (IRF9; 4.2-fold increase, p < 0.0001), Signal transducer and activator of transcription 1 (STAT1; 7.1-fold increase, p < 0.0001), and Interferon Alpha Inducible Protein 27 (IFI27; 66.3-fold increase, p < 0.0001). We also utilized TCGA datasets deposited in cBioportal and KMplotter to relate mRNA expression levels to overall survival outcomes. These increased levels of mRNA expression were found to be prognostically significant, whereby patients with high expression levels of either TGFB2, IRF9, or IFI27 showed median OS times ranging from 16 to 20 months (p < 0.01 compared to 72 months for patients with low levels of expression for both TGFB2 and either IRF9 or IFI27). Examination of the KMplotter database determined the prognostic impact of TGFB2 mRNA expression levels by comparing patients expressing high versus low levels of TGFB2 (50th percentile cut-off) in low macrophage TME. In TME with low macrophage levels, patients with high levels of TGFB2 mRNA exhibited significantly shorter OS outcomes than patients with low TGFB2 mRNA levels (Median OS of 15.3 versus 72.7 months, p < 0.0001). Furthermore, multivariate Cox regression models were applied to control for age at diagnosis. Nine genes exhibited significant increases in hazard ratios for TGFB2 mRNA expression, marker gene mRNA expression, and a significant interaction term between TGFB2 and marker gene expression (mRNA for markers: C1QA, CD74, HLA-DQB1, HLA-DRB1, HLA-F, IFI27, IRF9, LGALS9, MARCO). The results of our study suggest that a combination of pharmacological tools can be used in treating PDAC patients, targeting both TGFB2 and the components of the type-I interferon signaling pathway. The significant statistical interaction between TGFB2 and the nine marker genes suggests that TGFB2 is a negative prognostic indicator at low levels of the IFN-I activated genes and TAM marker expression, including the immune checkpoint LGALS9 (upregulated 16.5-fold in tumor tissue; p < 0.0001). [ABSTRACT FROM AUTHOR]

Summary The chromosomal translocation t(1;6)(p35.3;p25.2) is a rare but recurrent aberration in chronic lymphocytic leukaemia (CLL). We report molecular characterization of 10 cases and show that this translocation juxtaposes interferon regulatory factor 4 (IRF4) on 6p25 with regulator of chromosome condensation 1 (RCC1) on 1p35. The breakpoints fell within the 5′ untranslated regions of both genes, resulting in RCC1::IRF4 fusion transcripts without alterations of the protein‐coding sequences. Levels of expression of both RCC1 and IRF4 proteins were not obviously deregulated. The cases showed other mutations typical of CLL and we confirm previously reported skewing towards the IGHV‐unmutated subtype. RCC1::IRF4 fusion characterizes a rare subset of CLL. [ABSTRACT FROM AUTHOR]

Background and Purpose: Traditional Chinese medicine (TCM) played an important role in controlling the COVID‐19 pandemic, but the scientific basis and its active ingredients are still weakly studied. This study aims to decipher the underlying anti‐SARS‐CoV‐2 mechanisms of glycyrrhetinic acid (GA). Experimental Approach: GA's anti‐SARS‐CoV‐2 effect was verified both in vitro and in vivo. Homogeneous time‐resolved fluorescence assays, biolayer interferometry technology, and molecular docking were employed to examine interactions of GA with human stimulator of interferon genes (hSTING). Immunofluorescence staining, western blot, and RT‐qPCR were used to investigate nuclear translocation of interferon regulatory factor 3 (IRF3) and levels of STING target genes. Pharmacokinetics of GA was studied in mice. Key Results: GA could directly bind to Ser162 and Tyr240 residues of hSTING, thus up‐regulating downstream targets and activation of the STING signalling pathway. Such activation is crucial for limiting the replication of SARS‐CoV‐2 Omicron in Calu‐3 cells and protecting against lung injury induced by SARS‐CoV‐2 Omicron infection in K18‐ACE2 transgenic mice. Immunofluorescence staining and western blot indicated that GA increased levels of phosphorylated STING, phosphorylated TANK‐binding kinase‐1, and cyclic GMP‐AMP synthase (cGAS). Importantly, GA increased nuclear translocation of IRF3. Pharmacokinetic analysis of GA in mice indicated it can be absorbed into circulation and detected in the lung at a stable level. Conclusion and Implications: Activation of the cGAS‐STING pathway through the GA‐STING‐IRF3 axis is essential for the antiviral activity of GA in mice, providing new insights into the potential translation of GA for treating SARS‐CoV‐2 in patients. [ABSTRACT FROM AUTHOR]

Loss-of-function mutations in nucleotide-binding oligomerization domain 2 (NOD2) constitute the primary risk factors for Crohn's disease. NOD2 is an intracellular sensor for muramyl dipeptide (MDP), a small molecule derived from the peptidoglycan layer of bacterial cell wall. Although NOD2 is involved in host immune responses, much attention has been paid to the involvement of NOD2 in the maintenance of intestinal homeostasis. Despite the fact that the proinflammatory cytokine and chemokine responses induced by NOD2 activation alone are weaker than those induced by toll-like receptors (TLRs), NOD2 plays a crucial role in host defense against invading pathogens and in the regulation of immune responses. Recent studies have highlighted the importance of negative regulatory functions of NOD2 in TLRs-mediated proinflammatory cytokine responses. MDP-mediated activation of NOD2 induces interferon regulatory factor 4 (IRF4) expression, thereby suppressing nuclear factor-kB-dependent colitogenic cytokine responses through the inhibition of Lys(K)63-linked polyubiquitination on receptor-interacting serine/threonine protein kinase 2. MDP-mediated activation of NOD2 also downregulates TLR9-induced type I IFN responses by inhibiting the K63-linked polyubiquitination of TNF receptor-associated factor 3 via deubiquitinating enzyme A (DUBA) expression. Thus, NOD2 exerts dual negative regulation of TLRs-mediated proinflammatory cytokine and type I IFN responses by inducing the expression of IRF4 and DUBA, respectively. In this review, we summarize the molecular mechanisms whereby NOD2 activation suppresses TLRs-mediated proinflammatory and type I IFN responses. In addition, we discuss the clinical relevance of the NOD2-mediated negative regulation of TLRs in inflammatory bowel disease. [ABSTRACT FROM AUTHOR]

Background: The incidence of inflammatory bowel disease (IBD) is on the rise in developing countries, and investigating the underlying mechanisms of IBD is essential for the development of targeted therapeutic interventions. Interferon regulatory factor 7 (IRF7) is known to exert pro-inflammatory effects in various autoimmune diseases, yet its precise role in the development of colitis remains unclear. Methods: We analyzed the clinical significance of IRF7 in ulcerative colitis (UC) by searching RNA-Seq databases and collecting tissue samples from clinical UC patients. And, we performed dextran sodium sulfate (DSS)-induced colitis modeling using WT and Irf7−/− mice to explore the mechanism of IRF7 action on colitis. Results: In this study, we found that IRF7 expression is significantly reduced in patients with UC, and also demonstrated that Irf7−/− mice display heightened susceptibility to DSS-induced colitis, accompanied by elevated levels of colonic and serum pro-inflammatory cytokines, suggesting that IRF7 is able to inhibit colitis. This increased susceptibility is linked to compromised intestinal barrier integrity and impaired expression of key molecules, including Muc2, E-cadherin, β-catenin, Occludin, and Interleukin-28A (IL-28A), a member of type III interferon (IFN-III), but independent of the deficiency of classic type I interferon (IFN-I) and type II interferon (IFN-II). The stimulation of intestinal epithelial cells by recombinant IL-28A augments the expression of Muc2, E-cadherin, β-catenin, and Occludin. The recombinant IL-28A protein in mice counteracts the heightened susceptibility of Irf7−/− mice to colitis induced by DSS, while also elevating the expression of Muc2, E-cadherin, β-catenin, and Occludin, thereby promoting the integrity of the intestinal barrier. Conclusion: These findings underscore the pivotal role of IRF7 in preserving intestinal homeostasis and forestalling the onset of colitis. [ABSTRACT FROM AUTHOR]

The article in Clinical & Experimental Allergy explores how exposure to house dust mite (HDM) can promote the development of allergy to egg white in mice. The study found that inhalation of egg white and HDM led to systemic Th2 responses in mice, indicating a potential link between respiratory exposure to food allergens and systemic sensitization. The research suggests that prior sensitization to egg proteins through the respiratory tract, facilitated by HDM components, could lead to food allergies when egg is later ingested. The study highlights the adjuvant activity of HDM in enhancing the development of a Th2-driven immune response to egg white through the airways, with protease activity playing a modest role in this context. [Extracted from the article]

Influenza A virus (IAV) infection while primarily affecting the lungs, is often associated with cardiovascular complications. However, the mechanisms underlying this association are not fully understood. Here, we investigated the potential role of FBXL19, a member of the Skp1–Cullin-1–F-box family of E3 ubiquitin ligase, in IAV-induced cardiac inflammation. We demonstrated that FBXL19 overexpression in endothelial cells (ECs) reduced viral titers and IAV matrix protein 1 (M1) levels while increasing antiviral gene expression, including interferon (IFN)-α, -β, and -γ and RANTES (regulated on activation normal T cell expressed and secreted) in the cardiac tissue of IAV-infected mice. Moreover, EC-specific overexpression of FBXL19 attenuated the IAV infection-reduced interferon regulatory factor 3 (IRF3) level without altering its mRNA level and suppressed cardiac inflammation. Furthermore, IAV infection triggered cellular senescence programs in the heart as indicated by the upregulation of p16 and p21 mRNA levels and the downregulation of lamin-B1 levels, which were partially reversed by FBXL19 overexpression in ECs. Our findings indicate that EC-specific overexpression of FBXL19 protects against IAV-induced cardiac damage by enhancing interferon-mediated antiviral signaling, reducing cardiac inflammation, and suppressing cellular senescence programs. NEW & NOTEWORTHY: Our study reveals a novel facet of IAV infection, demonstrating that it can trigger cellular senescence within the heart. Intriguingly, upregulation of endothelial FBXL19 promotes host innate immunity, reduces cardiac senescence, and diminishes inflammation. These findings highlight the therapeutic potential of targeting FBXL19 to mitigate IAV-induced cardiovascular complications. [ABSTRACT FROM AUTHOR]

Interferon regulatory factors (IRFs) comprise a family of nine transcription factors in mammals. IRFs exert broad effects on almost all aspects of immunity but are best known for their role in the antiviral response. Over the past two decades, IRFs have been implicated in metabolic physiology and pathophysiology, partly as a result of their known functions in immune cells, but also because of direct actions in adipocytes, hepatocytes, myocytes and neurons. This Review focuses predominantly on IRF3 and IRF4, which have been the subject of the most intense investigation in this area. IRF3 is located in the cytosol and undergoes activation and nuclear translocation in response to various signals, including stimulation of Toll-like receptors, RIG-I-like receptors and the cGAS–STING pathways. IRF3 promotes weight gain, primarily by inhibiting adipose thermogenesis, and also induces inflammation and insulin resistance using both weight-dependent and weight-independent mechanisms. IRF4, meanwhile, is generally pro-thermogenic and anti-inflammatory and has profound effects on lipogenesis and lipolysis. Finally, new data are emerging on the role of other IRF family members in metabolic homeostasis. Taken together, data indicate that IRFs serve as critical yet underappreciated integrators of metabolic and inflammatory stress. Interferon regulatory factors (IRFs) are well known as mediators of the antiviral response but there is growing appreciation of their role in metabolism. This Review discusses the current understanding of IRFs as metabolic regulators, with a particular focus on IRF3 and IRF4. Key points: Interferon regulatory factors (IRFs) comprise a family of nine transcription factors that evolved coincident with the development of multicellularity in animals and serve to integrate the response to stress, most notably related to infection and inflammation. IRFs help to coordinate metabolic physiology and mediate key aspects of metabolic pathophysiology in diseases such as obesity, type 2 diabetes mellitus and metabolic-associated steatotic liver disease. There is increasing awareness that IRFs not only affect metabolism through their effects on immune cells but also by altering transcription in parenchymal cells such as adipocytes, hepatocytes, myocytes and neurons. IRF3 is generally pro-inflammatory and promotes obesity, insulin resistance, and hepatic steatosis and might also mediate some of the transcriptional actions of leptin in the hypothalamus. IRF4 is generally anti-inflammatory and has essential roles in adipogenesis, lipolysis and thermogenesis in adipose tissue. Other IRFs are beginning to be implicated in metabolic homeostasis, and more insights are likely to emerge over the next few years. [ABSTRACT FROM AUTHOR]

Although mitochondrial aldehyde dehydrogenase 2 (ALDH2) is involved in aging and aging-related diseases, its role in the regulation of human mesenchymal stem cell (MSC) senescence has not been investigated. This study aimed to determine the role of ALDH2 in regulating MSC senescence and illustrate the potential mechanisms. MSCs were isolated from young (YMSCs) and aged donors (AMSCs). Senescence-associated β-galactosidase (SA-β-gal) staining and Western blotting were used to assess MSC senescence. Reactive oxygen species (ROS) generation and mitochondrial membrane potential were determined to evaluate mitochondrial function. We showed that the expression of ALDH2 increased alongside cellular senescence of MSCs. Overexpression of ALDH2 accelerated YMSC senescence whereas down-regulation alleviated premature senescent phenotypes of AMSCs. Transcriptome and biochemical analyses revealed that an elevated ROS level and mitochondrial dysfunction contributed to ALDH2 function in MSC senescence. Using molecular docking, we identified interferon regulatory factor 7 (IRF7) as the potential target of ALDH2. Mechanistically, ectopic expression of ALDH2 led to mitochondrial dysfunction and accelerated senescence of MSCs by increasing the stability of IRF7 through a direct physical interaction. These effects were partially reversed by knockdown of IRF7. These findings highlight a crucial role of ALDH2 in driving MSC senescence by regulating mitochondrial homeostasis, providing a novel potential strategy against human aging-related diseases. The proposed mechanisms involved in ALDH2 mediation of MSC senescence via regulation of mitochondrial homeostasis. [Display omitted] • The mRNA and protein level of ALDH2 was much higher in AMSCs than YMSCs. • Overexpression of ALDH2 accelerated YMSC senescence whereas down-regulation rejuvenated senescent phenotypes of AMSCs. • Overexpression of ALDH2 compromised mitochondrial function and induced ROS generation, leading to MSC senescence. • Overexpression of ALDH2 enhanced the protein level of IRF7, leading to mitochondrial dysfunction and accelerated MSC senescence. [ABSTRACT FROM AUTHOR]

Ferroptosis is a form of cell death that is triggered by the presence of ferrous ions and is characterized by lipid peroxidation induced by these ions. The mechanism exhibits distinct morphological characteristics compared to apoptosis, autophagy, and necrosis. A notable aspect of ferroptosis is its ability to inhibit uncontrolled tumor replication and immortalization, especially in malignant, drug-resistant, and metastatic tumors. Additionally, immunotherapy, a novel therapeutic approach for tumors, has been found to have a reciprocal regulatory relationship with ferroptosis in the context of anti-tumor therapy. A comprehensive analysis of ferroptosis and immunotherapy in tumor therapy is presented in this paper, highlighting the potential for mutual adjuvant effects. Specifically, we discuss the mechanisms underlying ferroptosis and immunotherapy, emphasizing their ability to improve the tumor immune microenvironment and enhance immunotherapeutic effects. Furthermore, we investigate how immunotherapeutic factors may increase the sensitivity of tumor cells to ferroptosis. We aim to provide a prospective view of the promising value of combined ferroptosis and immunotherapy in anticancer therapy by elucidating the mutual regulatory network between each. Ferroptosis in the tumor microenvironment involves intricate crosstalk between tumor cells and immune cells. Through MHC recognition, CD8+T cells activate the JAK1/STAT1 pathway in tumor cells, impairing the function of System Xc and reducing GSH and GPX4 expression to promote tumor cell ferroptosis. Additionally, activation of the STAT1-IRF1-ACSL4 pathway could also promote ferroptosis. The blockade of the antioxidant pathway in tumor cells induces ferroptosis, and the released DAMPs could promote DCs maturation through the cGAMP-STING-TBK1 pathway, leading to antigen presentation that activates CD8+T cells. The release of DAMPs also induces the M1-type polarization of macrophages, which exerts an anti-tumor effect. The anti-tumor effects of CD8+T cells could also be enhanced by blocking inhibitory immune checkpoints such as PD-1, PD-L1, CTLA4, and LAG3. Abbreviations: ACSL4, acyl-CoA synthetase long-chain family member 4; BH4, tetrahydrobiopterin; cGAMP, cyclic GMP-AMP; CTLA4, cytotoxic T lymphocyte-associated antigen-4; DCs, dendritic cells; DHFR, dihydrofolate reductase; DHODH, dihydroorotate dehydrogenase; GPX4, glutathione peroxidase 4; GSH, glutathione; HIF-1α, Hypoxia-Inducible Factor-1α;IFN-γ, interferon-γ; IRF1, interferon regulatory factor 1;IRP1, iron regulatory protein 1; JAK 1, janus kinase; LAG3, lymphocyte activation gene 3; MHC, major histocompatibility complex; NRF2, nuclear factor erythroid-2-related factor 2; PD-1, programmed death protein -1; PD-L1, programmed death ligand 1; PUFA, polyunsaturated fatty acid; ROS, reative oxygen species; STAT1, signal transducer and activator of transcription 1; STING, stimulator of interferon genes; TBK1, TANK-binding kinase 1 TLR2, toll-like receptor 2. This diagram was drawn by Figdraw (www.figdraw.com). [ABSTRACT FROM AUTHOR]

Expression of the classical interferon (IFN) stimulated genes (ISGs) increases in the endometrial stroma and glandular epithelium (GE) through activation of signal transducer and activator of transcription (STAT) signaling in response to the secretion of IFN tau (IFNT) and IFN gamma (IFNG) by the conceptuses of ruminants, including cattle and sheep, and pigs, respectively. The first of the classical ISGs to be characterized was ISG15 in cattle. Classical ISGs are not expressed by the endometrial luminal epithelium (LE) due to the expression of interferon regulatory factor 2 (IRF2) in the LE that prevents the expression of ISGs in the LE. Classical ISG expression in the endometrium serves as a reliable indicator of conceptus health and elongation in cattle. There are also nonclassical ISGs that are upregulated in endometrial LE in response to progesterone (P4) that are further stimulated by IFNT in sheep, the intracellular signaling pathway responsible for IFN effects on expression is unknown. ISGs are also upregulated in extrauterine tissues including CL and peripheral blood mononuclear cells (PBMCs). The expression of ISGs by the PBMCs of cattle serves as an early prognosticator of pregnancy. The physiological roles of ISGs remain obscure, but evidence suggests that they are at least in part involved in modifying the immune system to support endometrial remodeling necessary for the successful implantation of the conceptus. Our understanding of these ISGs is primarily the result of work from the laboratories of Drs Fuller Bazer, Thomas (Tod) Hansen, Gregory Johnson, Hakhyun Ka, Patrick Lonergan, Troy Ott, and Thomas Spencer. [ABSTRACT FROM AUTHOR]

Introduction: Programmed death-ligand 1 (PD-L1) plays essential roles in the negative regulation of anti-tumor immunity. However, the regulatory mechanisms of PD-L1 expression need further exploration. MORC family CWtype zinc finger 3 (MORC3) is a transcriptional factor that regulates innate immune responses, but the expression and roles of MORC3 in cancers remain largely unknown. The present study explored the expression of MORC3 in cancers at both transcriptional and translational levels. Methods: The target genes and pathways were analyzed using RNA interference (RNAi), RNA sequencing (RNA-seq), and quantitative real-time polymerase chain reaction (qRT-PCR) technology in head and neck cancer cells. The expression of MORC3 and its target genes were also analyzed in single cancer cells. Results: MORC3 was significantly downregulated in multiple cancers, including head and neck cancer, and low expression of MORC3 was associated with poor overall survival. MORC3 knockdown significantly increased the expression of many immune-related genes, including interferon (IFN)-associated genes [MX dynamin like GTPase 2 (MX2), interferon induced protein with tetratricopeptide repeats 1 (IFIT1), interferon induced protein with tetratricopeptide repeats 2 (IFIT2), interferon regulatory factor 7 (IRF7), interferon regulatory factor 9 (IRF9), interferon induced protein 44 like (IFI44L), interferon induced transmembrane protein 1 (IFITM1), interferon induced transmembrane protein 3 (IFITM3), interferon induced protein 44 (IFI44), and interferon induced with helicase C domain 1 (IFIH1)]. MORC3 knockdown significantly upregulated PD-L1 and signal transducer and activator of transcription 1 (STAT1) expression. Moreover, the LINC00880 immune-related long non-coding RNA (lnc-RNA) was upregulated by MORC3 knockdown. Silencing LINC00880 attenuated PD-L1 expression. MORC3 knockdown also increased the expression of cellular proliferation-related genes and promoted cancer cell proliferation. Conclusion: The present study demonstrated that MORC3 regulates IFNassociated pathways and is a novel repressor of PD-L1 expression and cancer cell proliferation. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction Methods Results Conclusions Anti‐CD38 therapeutic modalities (e.g., daratumumab) can impede classical CD38 and CD138 gating use for plasma cell (PC) detection in multiple myeloma (MM) patients with minimal residual disease (MRD). We assessed the applicability of CD229, CD269, and interferon regulatory factor (IRF‐4) for PC detection in MM MRD patients.Bone marrow samples were collected from patients with MM. Through multiparameter flow cytometry, we evaluated the suitability of CD229, CD269, and IRF‐4 for distinguishing PCs from other hematopoietic cells and compared their expression pattern on normal PCs (nPCs) and aberrant PCs (aPCs). We also assessed IRF‐4 expression stability after sample storage under different conditions. A 10‐color MRD antibody panel was used to determine whether IRF‐4 is an alternative primary PC‐gating marker for MM MRD assessment.IRF‐4 was expressed specifically on all PCs; its mean fluorescence intensity (MFI) was highest on PCs among all hematopoietic cells. This MFI did not decrease even after sample storage at 4°C or 25°C for 72 h. In all 42 MRD assessment samples, except for samples (n = 10) with no PCs, the use of IRF‐4 enabled accurate nPC (n = 12), aPC (n = 13), and nPC + aPC (n = 7) identification. Even samples from daratumumab‐treated patients had high IRF‐4 MFI, with no difference between pre‐treatment and post‐treatment (n = 7; p = 0.610).IRF‐4 demonstrates high MFI on PCs, and it is not expressed on other leukocytes. In MM patients with MRD, daratumumab treatment does not affect IRF‐4 expression. IRF‐4 is a promising marker for PC identification in MRD assessment of MM patients undergoing anti‐CD38 therapy. [ABSTRACT FROM AUTHOR]

Background: This study aimed to investigate the differential expression levels of the cGAS-STING pathway in peripheral blood mononuclear cells (PBMCs) of spinal tuberculosis (TB) patients with different progression and its feasibility as a diagnostic marker. Methods: Peripheral blood and medical records of 25 patients with spinal TB and 10 healthy individuals, were prospectively collected and analyzed. PBMCs and serum were extracted from peripheral blood and the expression levels of the cGAS-STING pathway in PBMCs were measured by real-time PCR (RT-PCR) and serum interferon β (IFN-β) expression levels were measured by enzyme-linked immunosorbent assay (ELISA). The expression of Interferon regulatory Factor 3 (IRF3) in PBMCs was measured using western blot. Statistical analysis was performed using the SPSS 26.0 statistical package. Results: The results showed that the expression level of the TANK-binding kinase 1 (TBK1) and IRF3 was significantly higher in PBMCs (P < 0.05), in patients with active lesions than in patients with stable lesions. The serum concentration of IFN-β was significantly higher in patients with active lesions (P = 0.028). Compared with healthy individuals, the expression level of the cGAS-STING pathway was elevated in PBMCs of TB patients (P < 0.05), and the difference in the expression level of IFN-β was not statistically significant (P > 0.05), and the serum IFN-β concentration was elevated (P < 0.05). The calculated AUC values for TBK1 and IRF3 in PBMCs, IFN-β in serum and erythrocyte sedimentation rate (ESR) to distinguish between patients with active and stable lesions were 0.732, 0.714, 0.839, and 0.714 respectively. Conclusions: The expression level of TBK1 and IRF3 in PBMCs, and IFN-β in the serum of patients with spinal TB is positively correlated with disease activity. TBK1 has higher specificity and IFN-β in serum has higher sensitivity when used to differentiate between patients with active and stable lesions. [ABSTRACT FROM AUTHOR]

Heritable mutations in BRCA1 associate with increased risk of high-grade serous tubo-ovarian cancer. Nongenetic risk factors associated with this cancer, which arises from fallopian tube epithelial (FTE) cells, suggests a role for repetitive ovulation wherein FTE cells are exposed to inflammatory signaling molecules within follicular fluid. We previously reported increased NFkB and EGFR signaling in BRCA1- deficient primary FTE cells, with follicular fluid exposure further increasing abundance of interferon-stimulated gene (ISG) transcripts, including the ubiquitin-like protein ISG15 and other ISGylation pathway members. Both NFkB and type I interferon signaling are upregulated by stimulation of cGASSTING or MDA5 and RIGI pattern recognition receptors. Since some pattern recognition receptors and their signal transduction pathway members are ISGylated, we tested the impact of ISG15 and ISGylation on interferon regulatory factor 3 (IRF3) and NFkB signaling through cGAS-STING or RIGI and MDA5 activation. Expression of ISG15 or UBA7, the E1- like ISG15-activating enzyme, in immortalized FTE cells was disrupted by CRISPR gene editing. Activation of IRF3 by RIGI or MDA5 but not cGAS-STING was attenuated by loss of either ISG15 or UBA7 and this was reflected by a similar effect on NFkB activation and downstream targets. Loss of ISGylation decreased levels of both MDA5 and RIGI, with knockdown of RIGI but not MDA5, decreasing IRF3 and NFkB activation in parental cells. These finding indicate that ISGylation enhances the ability of dsRNA to activate cytokine release and proinflammatory signaling. Further work to explore ISGylation as a target for prevention of high-grade serous tubo-ovarian cancer in BRCA1 mutation carriers is warranted. [ABSTRACT FROM AUTHOR]

Epstein-Barr virus (EBV), the causative agent of infectious mononucleosis, persistently infects over 90% of the human adult population and is associated with several human cancers. To establish life-long infection, EBV tampers with the induction of type I interferon (IFN I)-dependent antiviral immunity in the host. How various EBV genes help orchestrate this crucial strategy is incompletely defined. Here, we reveal a mechanism by which the EBV nuclear antigen 3A (EBNA3A) may inhibit IFNβ induction. Using proximity biotinylation we identify the histone acetyltransferase P300, a member of the IFNβ transcriptional complex, as a binding partner of EBNA3A. We further show that EBNA3A also interacts with the activated IFN-inducing transcription factor interferon regulatory factor 3 that collaborates with P300 in the nucleus. Both events are mediated by the N-terminal domain of EBNA3A. We propose that EBNA3A limits the binding of interferon regulatory factor 3 to the IFNβ promoter, thereby hampering downstream IFN I signaling. Collectively, our findings suggest a new mechanism of immune evasion by EBV, affected by its latency gene EBNA3A. [ABSTRACT FROM AUTHOR]

Host cells have evolved an intricate regulatory network to fine tune the type-I interferon responses. However, the full picture of this regulatory network remains to be depicted. In this study, we found that knock out of zinc-finger CCHC-type containing protein 8 (ZCCHC8) impairs the replication of influenza A virus (IAV), Sendai virus (Sev), Japanese encephalitis virus (JEV), and vesicular stomatitis virus (VSV). Further investigation unveiled that ZCCHC8 suppresses the type-I interferon responses by targeting the interferon regulatory factor 3 (IRF3) signaling pathway. Mechanistically, ZCCHC8 associates with phosphorylated IRF3 and disrupts the interaction of IRF3 with the co-activator CREB-binding protein (CBP). Additionally, the direct binding of ZCCHC8 with the IFN-stimulated response element (ISRE) impairs the ISRE-binding of IRF3. Our study contributes to the comprehensive understanding for the negative regulatory network of the type-I interferon responses and provides valuable insights for the control of multiple viruses from a host-centric perspective. IMPORTANCE The innate immune responses serve as the initial line of defense against invading pathogens and harmful substances. Negative regulation of the innate immune responses plays an essential role in avoiding auto-immune diseases and over-activated immune responses. Hence, the comprehensive understanding of the negative regulation network for innate immune responses could provide novel therapeutic insights for the control of viral infections and immune dysfunction. In this study, we report that ZCCHC8 negatively regulates the type-I interferon responses. We illustrate that ZCCHC8 impedes the IRF3-CBP association by interacting with phosphorylated IRF3 and competes with IRF3 for binding to ISRE. Our study demonstrates the role of ZCCHC8 in the replication of multiple RNA viruses and contributes to a deeper understanding of the negative regulation system for the type-I interferon responses. [ABSTRACT FROM AUTHOR]

The microenvironment of a cancer stem cell (CSC) niche is often found in coexistence with cancer-associated fibroblasts (CAFs). Here, we show the first in-depth analysis of the interaction between primary triple-negative breast cancer stem cells (BCSCs) with fibroblasts. Using 2D co-culture models with specific seeding ratios, we identified stromal fibroblast aggregation at the BCSC cluster periphery, and, on closer observation, the aggregated fibroblasts was found to encircle BCSC clusters in nematic organization. In addition, collagen type I and fibronectin accumulation were also found at the BCSC–stromal periphery. MACE-Seq analysis of BCSC-encapsulating fibroblasts displayed the transformation of stromal fibroblasts to CAFs and the upregulation of fibrosis regulating genes of which the Interferon Regulatory Factor 6 (IRF6) gene was identified. Loss of function experiments with the IRF6 gene decreased fibroblast encapsulation around BCSC clusters in 2D co-cultures. In BCSC xenografts, fibroblast IRF6 expression led to an increase in the stromal area and fibroblast density in tumors, in addition to a reduction in necrotic growth. Based on our findings, we propose that fibroblast IRF6 function is an important factor in the development of the stromal microenvironment and in sustaining the BCSC tumor niche. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to elucidate the influence of IFN-gamma (IFN-γ) in neuroblastoma (NB) cells and reveal its potential underlying molecular mechanism. Methods: The Cell Counting Kit-8, Transwell apparatus, and flow cytometry were employed to assess cellular viability, migratory capacity, invasive potential, and apoptotic rates, respectively. RNA-seq combined with bioinformatics analysis revealed differentially expressed genes (DEGs) and their possible biological functions. Protein levels were determined by western blot analysis. Results: IFN-γ treatment resulted in diminished cell viability, mitigated migratory and invasive capabilities, and augmented apoptotic activity in the SK-N-BE (2) cell line, whereas it exhibited the opposite effect in SH-SY5Y cells. Furthermore, interferon regulatory factor 1 (IRF-1) was the common DEG in both IFN-γ-treated SK-N-BE (2) and SH-SY5Y cells. Additionally, we found that it was underexpressed in NB tissues. The depletion of IRF-1 promoted the progression of both SK-N-BE (2) and SH-SY5Y cells. Moreover, IRF-1 knockdown effectively counteracted the effects of IFN-γ on SK-N-BE (2) cells, while exacerbating them in SH-SY5Y cells. Conclusion: This study verified that IFN-γ exerted a distinct role in both N-Myc-and non-N-Myc-amplified NB cells, partially by mediating the expression of IRF-1, suggesting that it may serve as a potent agent for treating patients with NB. [ABSTRACT FROM AUTHOR]

Background and objectives: The type I interferon (IFN) signature has been found to be overactivated in many systemic autoimmune diseases. This may be explained by impaired regulation of interferon-stimulated genes (ISGs) as well as interferon-induced protein 44 (IFI44) expression via their regulatory mechanisms via interferon regulatory factors (IRFs). Patients and methods: This case-control study includes two groups: 50 RA patients and 50 healthy controls. The quantification of IFI44 and IRF4 expression levels by the real-time PCR technique was estimated. Disease Activity Score-28 (DAS-28) was estimated for RA patients only. Results: Among the RA patients, there were statistically significant increased ESR, CRP, TLC, RF, and anti-CCP levels (p value < 0.001) and significant increased expression of the IFI44 and IRF4 genes (p value < 0.001). There was a significant positive correlation between the IFI44 and IRF4, and there was a significant correlation between both and ESR and anti-CCP among RA patients. At a cutoff point of 1.95, IFI44 shows higher sensitivity and specificity values than IRF4 for the diagnosis of RA. Conclusion: IFI44 was more sensitive for RA diagnosis than IRF4. IFI44 and IRF4 overexpression could be promising predictors of RA diagnosis and might become useful clinical tools to guide therapeutic strategies. [ABSTRACT FROM AUTHOR]

Repeated sevoflurane exposure in neonatal mice triggers neuroinflammation with detrimental effects on cognitive function. Yet, the mechanism of the sevoflurane-induced cytokine response is largely unknown. In this study, we reveal that 3-MA, an autophagy inhibitor, attenuated the sevoflurane-induced neuroinflammation and cognitive dysfunction, including the decreased freezing time and fewer platform crossings, in the neonate mice. 3-Methyladenine (3-MA) suppressed sevoflurane-induced expression of interleukin-6 and tumor necrosis factor-alpha in vitro. Moreover, sevoflurane activates IRF3, facilitating cytokine transcription in an AKT3-dependent manner. Mechanistically, sevoflurane-induced autophagic degradation of dehydrocholesterol-reductase-7 (DHCR7) resulted in accumulations of its substrate 7-dehydrocholesterol (7-DHC), mimicking the effect of sevoflurane on AKT3 activation and IRF3-driven cytokine expression. 3-MA significantly reversed sevoflurane-induced DHCR7 degradation, AKT phosphorylation, IRF3 activation, and the accumulation of 7-DHC in the hippocampal CA1 region. These findings pave the way for additional investigations aimed at developing novel strategies to mitigate postoperative cognitive impairment in pediatric patients. [Display omitted] • Autophagy promotes sevoflurane-induced neuroinflammation and cognitive dysfunction in neonatal mice. • Sevoflurane activates AKT3 and induces IRF3-driven cytokine expression in neurons. • Sevoflurane-induced autophagic degradation of DHCR7 results in accumulation of 7-DHC which activates AKT3. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Modern Laboratory Medicine is the property of Journal of Modern Laboratory Medicine Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The pathological role of interferon signaling is emerging in neuroinflammatory disorders, yet, the specific role of Interferon Regulatory Factor 3 (IRF3) in neuroinflammation remains poorly understood. Here, we show that global IRF3 deficiency delays TLR4-mediated signaling in microglia and attenuates the hallmark features of LPS-induced inflammation such as cytokine release, microglial reactivity, astrocyte activation, myeloid cell infiltration, and inflammasome activation. Moreover, expression of a constitutively active IRF3 (S388D/S390D: IRF3-2D) in microglia induces a transcriptional program reminiscent of the Activated Response Microglia and the expression of genes associated with Alzheimer's disease, notably apolipoprotein-e. Using bulk-RNAseq of IRF3-2D brain myeloid cells, we identified Z-DNA binding protein-1 (ZBP1) as a target of IRF3 that is relevant across various neuroinflammatory disorders. Lastly, we show IRF3 phosphorylation and IRF3-dependent ZBP1 induction in response to Aβ in primary microglia cultures. Together, our results identify IRF3 as an important regulator of LPS and Aβ -mediated neuroinflammatory responses and highlight IRF3 as a central regulator of disease-specific gene activation in different neuroinflammatory diseases. [ABSTRACT FROM AUTHOR]

The economic importance of lumpfish (Cyclopterus lumpus) is increasing, but several aspects of its immune responses are not well understood. To discover genes and mechanisms involved in the lumpfish antiviral response, fish were intraperitoneally injected with either the viral mimic polyinosinic:polycytidylic acid [poly(I:C)] or phosphate-buffered saline (PBS; vehicle control), and head kidneys were sampled 24 hours post-injection (hpi) for transcriptomic analyses. RNA sequencing (RNA-Seq) (adjusted p-value <0.05) identified 4,499 upregulated and 3,952 downregulated transcripts in the poly(I:C)-injected fish compared to the PBS-injected fish. Eighteen genes identified as differentially expressed by RNA-Seq were included in a qPCR study that confirmed the upregulation of genes encoding proteins with antiviral immune response functions (e.g., rsad2) and the downregulation of genes (e.g., jarid2b) with potential cellular process functions. In addition, transcript expression levels of 12 members of the interferon regulatory factor (IRF) family [seven of which were identified as poly(I:C)-responsive in this RNA-Seq study] were analyzed using qPCR. Levels of irf1a, irf1b, irf2, irf3, irf4b, irf7, irf8, irf9, and irf10 were significantly higher and levels of irf4a and irf5 were significantly lower in the poly(I:C)-injected fish compared to the PBS-injected fish. This research and associated new genomic resources enhance our understanding of the genes and molecular mechanisms underlying the lumpfish response to viral mimic stimulation and help identify possible therapeutic targets and biomarkers for viral infections in this species. [ABSTRACT FROM AUTHOR]

Autoimmune diseases, among the most common disorders of young adults, are mediated by genetic and environmental factors. Although CD4+FOXP3+ regulatory T cells (Tregs) play a central role in preventing autoimmunity, the molecular mechanism underlying their dysfunction is unknown. Here, we performed comprehensive transcriptomic and epigenomic profiling of Tregs in the autoimmune disease multiple sclerosis (MS) to identify critical transcriptional programs regulating human autoimmunity. We found that up-regulation of a primate-specific short isoform of PR domain zinc finger protein 1 (PRDM1-S) induces expression of serum and glucocorticoid-regulated kinase 1 (SGK1) independent from the evolutionarily conserved long PRDM1, which led to destabilization of forkhead box P3 (FOXP3) and Treg dysfunction. This aberrant PRDM1-S/SGK1 axis is shared among other autoimmune diseases. Furthermore, the chromatin landscape profiling in Tregs from individuals with MS revealed enriched activating protein–1 (AP-1)/interferon regulatory factor (IRF) transcription factor binding as candidate upstream regulators of PRDM1-S expression and Treg dysfunction. Our study uncovers a mechanistic model where the evolutionary emergence of PRDM1-S and epigenetic priming of AP-1/IRF may be key drivers of dysfunctional Tregs in autoimmune diseases. Editor's summary: Regulatory T cells (Tregs) are known to be dysfunctional in autoimmune diseases, but the cause of this dysfunction has not been fully elucidated. Here, Sumida et al. found that Tregs isolated from individuals with multiple sclerosis, an autoimmune disease of the central nervous system, had increased expression of the short isoform of PR domain zinc finger protein 1 (PRDM1-S), which destabilized expression of the essential Treg transcription factor FOXP3 and induced Treg dysfunction mediated through SGK1, a salt-sensing kinase. Upstream epigenetic analysis revealed a regulatory role for AP-1 and IRF transcription factors in this circuit. The authors detected similar up-regulation of PRDM1-S in other autoimmune diseases, suggesting that PRDM1-S overexpression may be a common feature of Treg dysfunction. —Courtney Malo [ABSTRACT FROM AUTHOR]

Osteoclasts are multinucleated bone-resorbing cells, and their formation is tightly regulated to prevent excessive bone loss. However, the mechanisms by which osteoclast formation is restricted remain incompletely determined. Here, we found that sterol regulatory element binding protein 2 (SREBP2) functions as a negative regulator of osteoclast formation and inflammatory bone loss. Cholesterols and SREBP2, a key transcription factor for cholesterol biosynthesis, increased in the late phase of osteoclastogenesis. The ablation of SREBP2 in myeloid cells resulted in increased in vivo and in vitro osteoclastogenesis, leading to low bone mass. Moreover, deletion of SREBP2 accelerated inflammatory bone destruction in murine inflammatory osteolysis and arthritis models. SREBP2-mediated regulation of osteoclastogenesis is independent of its canonical function in cholesterol biosynthesis but is mediated, in part, by its downstream target, interferon regulatory factor 7 (IRF7). Taken together, our study highlights a previously undescribed role of the SREBP2-IRF7 regulatory circuit as a negative feedback loop in osteoclast differentiation and represents a novel mechanism to restrain pathological bone destruction. [ABSTRACT FROM AUTHOR]

Introduction: Chronic obstructive pulmonary disease (COPD) is a frequent cause of morbidity and mortality. Dysregulated and enhanced immune-inflammatory responses have been described in COPD. Recent data showed impaired immune responses and, in particular, of interferon (IFNs) signaling pathway in these patients. Aim: To evaluate in peripheral lung of COPD patients, the expression of some of the less investigated key components of the innate immune responses leading to IFN productions including: IFN-receptors (IFNAR1/IFNAR2), IRF-3 and MDA-5. Correlations with clinical traits and with the inflammatory cell profile have been assessed. Methods: Lung specimens were collected from 58 subjects undergoing thoracic surgery: 22 COPD patients, 21 smokers with normal lung function (SC) and 15 non-smoker controls (nSC). The expression of IFNAR1, IFNAR2, IRF-3 and MDA-5, of eosinophils and activated NK cells (NKp46+) were quantified in the peripheral lung by immunohistochemistry. Results: A significant increase of IRF-3 + alveolar macrophages were observed in COPD and SC compared with nSC subjects. However, in COPD patients, the lower the levels of IRF-3 + alveolar macrophages the lower the FEV1 and the higher the exacerbation rate. The presence of chronic bronchitis (CB) was also associated with low levels of IRF-3 + alveolar macrophages. NKp46 + cells, but not eosinophils, were increased in COPD patients compared to nSC patients (p < 0.0001). Conclusions: Smoking is associated with higher levels of innate immune response as showed by higher levels of IRF-3 + alveolar macrophages and NKp46 + cells. In COPD, exacerbation rates, severe airflow obstruction and CB were associated with lower levels of IRF-3 expression, suggesting that innate immune responses characterize specific clinical traits of the disease. [ABSTRACT FROM AUTHOR]

Introduction: The immunological characteristics that could protect children with coronavirus disease 2019 (COVID-19) from severe or fatal illnesses have not been fully understood yet. Methods: Here, we performed single-cell RNA sequencing (scRNA-seq) analysis on peripheral blood samples of 15 children (8 with COVID-19) and compared them to 18 adults (13 with COVID-19). Results: The child-adult integrated single cell data indicated that children with the disease presented a restrained response to type I interferon in most of the major immune cell types, along with suppression of upstream interferon regulatory factor and toll-like receptor expression in monocytes, which was confirmed by in vitro interferon stimulation assays. Unlike adult patients, children with COVID-19 showed lower frequencies of activated proinflammatory CD14+ monocytes, possibly explaining the rareness of cytokine storm in them. Notably, natural killer (NK) cells in pediatric patients displayed potent cytotoxicity with a rich expression of cytotoxic molecules and upregulated cytotoxic pathways, whereas the cellular senescence, along with the Notch signaling pathway, was significantly downregulated in NK cells, all suggesting more robust cytotoxicity in NK cells of children than adult patients that was further confirmed by CD107a degranulation assays. Lastly, a modest adaptive immune response was evident with more naïve T cells but less activated and proliferated T cells while less naïve B cells but more activated B cells in children over adult patients. Conclusion: Conclusively, this preliminary study revealed distinct cell frequency and activation status of major immune cell types, particularly more robust NK cell cytotoxicity in PBMC that might help protect children from severe COVID-19. [ABSTRACT FROM AUTHOR]

Analyzing changes in gene expression within specific brain regions of individuals with Type 2 Diabetes (T2DM) who do not exhibit significant cognitive deficits can yield valuable insights into the mechanisms underlying the progression towards a more severe phenotype. In this study, transcriptomic analysis of the cortex and hippocampus of mice with long-term T2DM revealed alterations in the expression of 28 genes in the cerebral cortex and 15 genes in the hippocampus. Among these genes, six displayed consistent changes in both the cortex and hippocampus: Interferon regulatory factor 7 (Irf7), Hypoxia-inducible factor 3 alpha (Hif-3α), period circadian clock 2 (Per2), xanthine dehydrogenase (Xdh), and Transforming growth factor β-stimulated clone 22/TSC22 (Tsc22d3) were upregulated, while Claudin-5 (Cldn5) was downregulated. Confirmation of these changes was achieved through RT-qPCR. At the protein level, CLDN5 and IRF7 exhibited similar alterations, with CLDN5 being downregulated and IRF7 being upregulated. In addition, the hippocampus and cortex of the T2DM mice showed decreased levels of IκBα, implying the involvement of NF-κB pathways as well. Taken together, these results suggest that the weakening of the blood-brain barrier and an abnormal inflammatory response via the Interferon 1 and NF-κB pathways underlie cognitive impairment in individuals with long-standing T2DM [ABSTRACT FROM AUTHOR]

Esophageal cancer is common worldwide, with ESCC being the most frequent tumor in East Asia. Tumor-associated macrophages are an important component of the ESCC microenvironment. SUMOylation is a post-translational modification of proteins, and SUMO-specific proteases (SENPs) play an important role in de-SUMOylation. In human patients, we discovered that the levels of SENP3 were upregulated in the tumor-associated macrophages. Furthermore, the loss of SENP3 enhanced the alternative activation of macrophages in the 4-NQO-induced ESCC mice model. This is the first study to identify SENP3-mediated macrophage polarization via the de-SUMOylation of interferon regulatory factor 4 (IRF4) at the K349 site. Alternative activation of macrophages increases the migration and invasion potential of ESCC cells and promotes their progression in vivo. Moreover, patients with relatively low SENP3 expression in macrophages exhibit higher primary PET SUVmax value and lymph node metastasis rates. In summary, this study revealed that SENP3-mediated IRF4 de-SUMOylation is crucial for the alternative activation of macrophages and influences the progression of ESCC. Highlights: • SENP3 expression is upregulated in macrophages in esophageal squamous cell carcinoma. • The absence of SENP3 in macrophages promotes the progression of esophageal squamous cell carcinoma both in patients and in the 4-NQO-induced ESCC mice model. • Loss of SENP3 promotes macrophages' alternative activation by attenuating the de-SUMOylation of IRF4 at the K349 site. • ESCC patients with relatively low SENP3 expression in macrophages had higher primary tumor SUVmax and lymph node metastasis rates. [ABSTRACT FROM AUTHOR]

Merkel cell polyomavirus (MCPyV) is the causative agent of the majority of Merkel cell carcinomas (MCC). The virus has limited coding capacity, with its early viral proteins, large T (LT) and small T (sT), being multifunctional and contributing to infection and transformation. A fundamental difference in early viral gene expression between infection and MCPyV-driven tumorigenesis is the expression of a truncated LT (LTtr) in the tumor. In contrast, sT is expressed in both conditions and contributes significantly to oncogenesis. Here, we identified novel functions of early viral proteins by performing genome-wide transcriptome and chromatin studies in primary human fibroblasts. Due to current limitations in infection and tumorigenesis models, we mimic these conditions by ectopically expressing sT, LT or LTtr, individually or in combination, at different time points. In addition to its known function in cell cycle and inflammation modulation, we reveal a fundamentally new function of sT. We show that sT regulates the type I interferon (IFN) response downstream of the type I interferon receptor (IFNAR) by interfering with the interferon-stimulated gene factor 3 (ISGF3)-induced interferon-stimulated gene (ISG) response. Expression of sT leads to a reduction in the expression of interferon regulatory factor 9 (IRF9) which is a central component of the ISGF3 complex. We further show that this function of sT is conserved in BKPyV. We provide a first mechanistic understanding of which early viral proteins trigger and control the type I IFN response, which may influence MCPyV infection, persistence and, during MCC progression, regulation of the tumor microenvironment. Author summary: Merkel cell polyomavirus (MCPyV) is the only human polyomavirus that causes cancer in humans. As with all human polyomaviruses, the available infection models are limited. Thus, many processes such as the host response to infection and its regulation by the virus to establish infection and persistence are poorly understood. To better understand this interplay of viral MCPyV proteins, we performed genome-wide transcriptome and chromatin studies in primary human fibroblasts and simulated infection and tumorigenesis conditions by ectopically expressing the early viral proteins individually or in combination at different time points. This allowed us to uncover a novel, previously undescribed function of polyomavirus sT, namely the reduction of the ISG response by affecting the ISGF3 complex, specifically by reducing IRF9 protein levels. This work sheds light on how early viral proteins influence the type I IFN response and how their interplay may affect MCPyV infection, persistence, and MCC progression. [ABSTRACT FROM AUTHOR]

Nonalcoholic fatty liver disease (NAFLD) is a serious disease. There are no specific drugs for it, in part because of the lack of effective models to aid drug development. However, it has been shown that three-dimensional organoid culture systems can reproduce the organ structure and maintain the gene expression profile of the original tissue. Therefore, we aimed to construct NAFLD models from liver organoids for pharmacological and mechanism studies. We successfully observed morphological changes in normal liver tissue in mouse liver organoids with positive albumin (ALB) expression and potential for differentiation toward hepatocyte-like cells. The mRNA expression of the hepatocyte markers ALB and hepatocyte nuclear factor 4 alpha increased after liver organoid differentiation. We observed free fatty acid (FFA)-induced lipid accumulation in organoids with significant increases in alanine aminotransferase, aspartate aminotransferase, total bilirubin, and triglyceride levels. Moreover, FFA-induced inflammatory cytokines (interleukin-6, tumor necrosis factor-α, and nitric oxide) and fibrosis indicators (collagen type I α1 and laminin α1) were also increased. In addition, RNA sequencing results showed that the expression of key genes [nucleotide oligomerization domain-like receptor (NLR) family apoptosis inhibitory protein, interferon regulatory factor (IRF) 3, and IRF7] involved in NAFLD metabolic abnormalities and insulin resistance in the NLR signaling pathway was altered after FFA induction of the liver organoids. Finally, we found that JC2-11 and lanifibranor limited the FFA-induced increase in oil-red lipid droplets, liver damage, inflammation, and liver fibrosis. In conclusion, tissue structure, gene expression, and the response of mouse liver organoids to drugs can partially mimic in vivo liver tissue. Liver organoids can successfully construct NAFLD models for drug discovery research. [ABSTRACT FROM AUTHOR]

Lung cancer is a major contributor to cancer deaths worldwide and is on the rise. Although surgical resection has been widely used as a standard therapy for lung cancer patients, the relapse rate after surgery is high. It is still unclear whether there is a potential drug that can reduce the probability of postsurgical recurrence in lung cancer patients. We used 5 typical lung cancer cell lines as well as 41 lung cancer tissue samples and paracancer tissue samples to investigate the expression levels of interferon regulatory factor 6 (IRF6) and tumor suppressor candidate 2 (TUSC2, also known as FUS1). We also treated lung cancer cells (H322 and A549) with different concentrations of sevoflurane to study its influence on lung cancer cell tumorigenesis. Lentivirus-mediated gain-of-function studies of IRF6 and FUS1 were applied to validate the role of IRF6 and FUS1 in lung cancer. Next, we used short hairpin RNA-mediated loss of function of IRF6 and luciferase, chromatin immunoprecipitation assays to validate the regulatory role of IRF6 on FUS1. Our findings reported that IRF6 was upregulated in lung cancer tissues, while FUS1 was downregulated. Functional assays revealed that sevoflurane inhibits lung cancer development by downregulating IRF6 expression. Luciferase and chromatin immunoprecipitation-quantitative real-time PCR assays uncovered that IRF6 represses FUS1 transcriptional expression in lung cancer cells. We have shown that sevoflurane prevents lung cancer development by downregulating IRF6 to stimulate FUS1 transcription, indicating that sevoflurane can be used as the potential anesthetic drug in surgical resection to reduce postoperative tumor relapse in lung cancer patients. [ABSTRACT FROM AUTHOR]

[Display omitted] • CFA intraplantar injection caused a significant decrease in the level of spinal IRF7. • IRF7 plays an important role in the regulation of inflammatory pain. • IRF7 regulates the activation of NF-κB pathways in the spinal cord. • IRF7 modulates the expression of inflammatory mediators in the spinal cord. It is known that nerve signals arising from sites of inflammation lead to persistent changes in the spinal cord and contribute to the amplification and persistence of pain. Nevertheless, the underlying mechanisms have not yet been completely elucidated. We identified differentially expressed genes in the lumbar (L4–L6) segment of the spinal cord from complete Freund's adjuvant (CFA) rats compared to control animals via high throughput sequencing. Based on differential gene expression analysis, we selected interferon regulatory factor 7 (IRF7) for follow-up experiments to explore its antinociceptive potential. An animal model of inflammatory pain was induced by intraplantar injection of CFA. We evaluated the effects of adeno-associated viral (AAV)-mediated overexpression of IRF7 in the spinal cord on pain-related behavior after CFA injection. Moreover, the activation of the nuclear factor-κB (NF-κB) and the expression of inflammatory cytokines were investigated to understand the underlying mechanisms related to the contribution of IRF7 to inflammatory pain. CFA intraplantar injection caused a significant decrease in the level of spinal IRF7, which is mainly expressed in the dorsal horn neurons and astrocytes. Moreover, IRF7 overexpression significantly attenuated pain-related behaviors, as well as the activity of NF-κB/p65 and the production of interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) in the spinal cord of CFA rats. Our data indicated that spinal IRF7 plays an important role in the regulation of inflammatory pain. Thus, IRF7 overexpression at the spinal cord level might represent a potential target for the treatment of inflammatory pain. [ABSTRACT FROM AUTHOR]

This article explores the connection between mitochondrial DNA (mtDNA) and vitiligo, an autoimmune disease that causes skin and hair depigmentation. The study reveals that vitiligo patients have an increased number of mtDNA variants, which leads to the release of mtDNA into the cytoplasm. This triggers an inflammatory response and promotes an autoimmune reaction against melanocytes. The findings suggest that targeting mtDNA release and oxidative stress could be potential therapeutic approaches for vitiligo. Additionally, the study suggests that vitiligo can be considered a mitochondrial disease, opening up the possibility of mitochondrial-specific treatments for managing the condition. [Extracted from the article]

Bile acids (BAs) are natural metabolites in mammals and have the potential to function as drugs against viral infection. However, the limited understanding of chenodeoxycholic acid (CDCA) receptors and downstream signaling, along with its lower suppression efficiency in inhibiting virus infection limits its clinical application. In this study, we demonstrate that farnesoid X receptor (FXR), the receptor of CDCA, negatively regulates interferon signaling, thereby contributing to the reduced effectiveness of CDCA against virus replication. FXR deficiency or pharmacological inhibition enhances interferon signaling activation to suppress virus infection. Mechanistically, FXR impairs the DNA binding and transcriptional abilities of activated interferon regulatory factor 3 (IRF3) through interaction. Reduced IRF3 transcriptional activity by FXR–IRF3 interaction significantly undermines the expression of Interferon Beta 1 (IFNB1) and the antiviral response of cells, especially upon the CDCA treatment. In FXR -deficient cells, or when combined with Z -guggulsterone (GUGG) treatment, CDCA exhibits a more potent ability to restrict virus infection. Thus, these findings suggest that FXR serves as a limiting factor for CDCA in inhibiting virus replication, which can be attributed to the "signaling-brake" roles of FXR in interferon signaling. Targeting FXR inhibition represents a promising pharmaceutical strategy for the clinical application of BAs metabolites as antiviral drugs. FXR inhibition enhances antiviral potency of chenodeoxycholic acid by relieving FXR interference with interferon signaling, indicating FXR as a promising target for augmenting bile acids' antiviral effects. [Display omitted] [ABSTRACT FROM AUTHOR]

Interferon regulatory factor 5 (IRF5) is a key transcription factor in inflammatory and immune responses, with its dysregulation linked to autoimmune diseases. Using bioinformatic approaches, including Basic Local Alignment Search Tool (BLAST) for sequence similarity searches, BLAST‐Like Alignment Tool (BLAT) for genome‐wide alignments, and several phylogenetics software, such as Multiple Alignment using Fast Fourier Transform (MAFFT), for phylogenetic analyses, we characterized the structure, origin, and evolutionary history of the human IRF5 pseudogene 1 (IRF5P1). Our analyses reveal that IRF5P1 is a chimeric processed pseudogene containing sequences derived from multiple sources, including IRF5‐like sequences from disparate organisms. We find that IRF5P1 is specific to higher primates, likely originating through an ancient retroviral integration event approximately 60 million years ago. Interestingly, IRF5P1 resides within the triple QxxK/R motif‐containing (TRIQK) gene, and its antisense strand is predominantly expressed as part of the TRIQK pre‐messenger RNA (mRNA). Analysis of publicly available RNA‐seq data suggests potential expression of antisense IRF5P1 RNA. We hypothesize that this antisense RNA may regulate IRF5 expression through complementary binding to IRF5 mRNA, with human genetic variants potentially modulating this interaction. The conservation of IRF5P1 in the primate lineage suggests its positive effects on primate evolution and innate immunity. This study highlights the importance of investigating pseudogenes and their potential regulatory roles in shaping lineage‐specific immune adaptations. [ABSTRACT FROM AUTHOR]

The adjuvant AS01 plays a key role in the immunogenicity of several approved human vaccines with demonstrated high efficacy. Its adjuvant effect relies on activation of the innate immune system. However, specific effects of AS01-adjuvanted vaccines on innate cell function and epigenetic remodeling, as described for Bacille Calmette-Guérin (BCG) and influenza vaccines, are still unknown. We assessed the long-term functional and epigenetic changes in circulating monocytes and dendritic cells induced by a model vaccine containing hepatitis B surface antigen and AS01 in healthy adults (NCT01777295). The AS01-adjuvanted vaccine, but not an Alum-adjuvanted vaccine, increased the number of circulating monocytes and their expression of human leukocyte antigen (HLA)–DR, which correlated with the magnitude of the memory CD4+ T cell response. Single-cell analyses revealed epigenetic alterations in monocyte and dendritic cell subsets, affecting accessibility of transcription factors involved in cell functions including activator protein-1 (AP-1), GATA, C/EBP, and interferon regulatory factor. The functional changes were characterized by a reduced proinflammatory response to Toll-like receptor activation and an improved response to interferon-γ, a cytokine critical for the adjuvant's mode of action. Epigenetic changes were most evident shortly after the second vaccine dose in CD14+ monocytes, for which accessibility differences of some transcription factors could persist for up to 6 months postvaccination. Together, we show that reprogramming of monocyte subsets occurs after vaccination with an AS01-adjuvanted vaccine, an effect that may contribute to the impact of vaccination beyond antigen-specific protection. Editor's summary: Most vaccines based on recombinant antigens rely on coadministration with an adjuvant to elicit a robust immune response. Although adjuvants are needed for many vaccines, it is less clear which adjuvant(s) should be paired with each immunogen. In two papers, Bechtold et al. and Arunachalam et al. performed comparative analyses to assess the effect of different adjuvants on the immune response. Bechtold et al. showed that an AS01-adjuvanted hepatitis B virus vaccine, which induces robust CD4+ T cell responses against the vaccine antigen, also elicited trained immunity in human recipients, which was not observed in an Alum-adjuvanted vaccine. Arunachalam et al. found that Matrix-M and 3M-052 + Alum adjuvantation induced robust immune responses to the R21 malaria vaccine in nonhuman primates, but a third comparator, GLA-LSQ, elicited a lower magnitude of response that was short lived. Although Matrix-M and 3M-052 + Alum induced robust and durable antibody responses, they elicited distinct innate immune responses, demonstrating that multiple innate immune mechanisms can program durable vaccine-induced immunity. These head-to-head comparisons in both humans and nonhuman primates demonstrate that selecting an adjuvant should be done carefully and that different adjuvants have distinct effects on both innate and adaptive immunity. —Courtney Malo [ABSTRACT FROM AUTHOR]

RNA helicases are involved in the innate immune response against pathogens, including bacteria and viruses; however, their mechanism in the human airway epithelial cells is still not fully understood. Here, we demonstrated that DEAH (Asp-Glu-Ala-His) box polypeptide 35 (DHX35), a member of the DExD/H (Asp-Glu-x-Asp/His)-box helicase family, boosts antiviral innate immunity in human airway epithelial cells. DHX35 knockdown attenuated the production of interferon-β (IFN-β), IL6, and CXCL10, whereas DHX35 overexpression increased their production. Upon stimulation, DHX35 was constitutively expressed, but it translocated from the nucleus into the cytosol, where it recognized cytosolic poly(I:C) and poly(dA:dT) via its HELICc domain. Mitochondrial antiviral signaling protein (MAVS) acted as an adaptor for DHX35 and interacted with the HELICc domain of DHX35 using amino acids 360–510. Interestingly, DHX35 interacted with retinoic acid-inducible gene 1 (RIG-I), enhanced the binding affinity of RIG-I with poly(I:C) and poly(dA:dT), and formed a signalsome with MAVS to activate interferon regulatory factor 3 (IRF3), NF-κB-p65, and MAPK signaling pathways. These results indicate that DHX35 not only acted as a cytosolic nucleic acid sensor but also synergized with RIG-I to enhance antiviral immunity in human airway epithelial cells. Our results demonstrate a novel molecular mechanism for DHX35 in RIG-I-mediated innate immunity and provide a novel candidate for drug and vaccine design to control viral infections in the human airway. Author summary: RIG-I plays an important role in defending against RNA viral infections, such as SARS-CoV-2, influenza virus, and vesicular stomatitis virus (VSV). DHX35 is a member of the Asp-Glu-x-Asp/His (DExD/H)-box helicase family. This study revealed a novel function of DHX35 in regulating activation of the RIG-I signaling pathway. DHX35 translocates from the nucleus into cytosol where it recognizes cytosolic nucleic acids upon stimulation, and interacts with MAVS to activate downstream signaling pathways. More importantly, DHX35 interacts with RIG-I to enhance its binding affinity to nucleic acids. Taken together, our findings demonstrate a novel molecular mechanism of RIG-I-mediated innate immunity in human airway epithelial cells. [ABSTRACT FROM AUTHOR]

Background: Z-DNA binding protein 1 (ZBP1) is a nucleic acid sensor that is involved in multiple inflammatory diseases, but whether and how it contributes to osteoarthritis (OA) are unclear. Methods: Cartilage tissues were harvested from patients with OA and a murine model of OA to evaluate ZBP1 expression. Subsequently, the functional role and mechanism of ZBP1 were examined in primary chondrocytes, and the role of ZBP1 in OA was explored in mouse models. Results: We showed the upregulation of ZBP1 in articular cartilage originating from OA patients and mice with OA after destabilization of the medial meniscus (DMM) surgery. Specifically, knockdown of ZBP1 alleviated chondrocyte damage and protected mice from DMM-induced OA. Mechanistically, tumor necrosis factor alpha induced ZBP1 overexpression in an interferon regulatory factor 1 (IRF1)-dependent manner and elicited the activation of ZBP1 via mitochondrial DNA (mtDNA) release and ZBP1 binding. The upregulated and activated ZBP1 could interact with receptor-interacting protein kinase 1 and activate the transforming growth factor-beta-activated kinase 1-NF-κB signaling pathway, which led to chondrocyte inflammation and extracellular matrix degradation. Moreover, inhibition of the mtDNA-IRF1-ZBP1 axis with Cyclosporine A, a blocker of mtDNA release, could delay the progression of DMM-induced OA. Conclusions: Our data revealed the pathological role of the mtDNA-IRF1-ZBP1 axis in OA chondrocytes, suggesting that inhibition of this axis could be a viable therapeutic approach for OA. [ABSTRACT FROM AUTHOR]

Systemic lupus erythematosus (SLE, lupus) is a debilitating, multisystem autoimmune disease that can affect any organ in the body. The disease is characterized by circulating autoantibodies that accumulate in organs and tissues, which triggers an inflammatory response that can cause permanent damage leading to significant morbidity and mortality. Lyn, a member of the Src family of non-receptor protein tyrosine kinases, is highly implicated in SLE as remarkably both mice lacking Lyn or expressing a gain-of-function mutation in Lyn develop spontaneous lupus-like disease due to altered signaling in B lymphocytes and myeloid cells, suggesting its expression or activation state plays a critical role in maintaining tolerance. The past 30 years of research has begun to elucidate the role of Lyn in a duplicitous signaling network of activating and inhibitory immunoreceptors and related targets, including interactions with the interferon regulatory factor family in the toll-like receptor pathway. Gain-offunction mutations in Lyn have now been identified in human cases and like mouse models, cause severe systemic autoinflammation. Studies of Lyn in SLE patients have presented mixed findings, which may reflect the heterogeneity of disease processes in SLE, with impairment or enhancement in Lyn function affecting subsets of SLE patients that may be a means of stratification. In this review, we present an overview of the phosphorylation and protein-binding targets of Lyn in B lymphocytes and myeloid cells, highlighting the structural domains of the protein that are involved in its function, and provide an update on studies of Lyn in SLE patients. [ABSTRACT FROM AUTHOR]