Expression Of Interferon Regulatory Factor Research Articles

NF-κB p65 and SETDB1 expedite lipopolysaccharide-induced intestinal inflammation in mice by inducing IRF7/NLR-dependent macrophage M1 polarization

Macrophages exhibit distinct phenotypes that are pro-inflammatory (M1) or anti-inflammatory (M2) in response to inflammation. In this study, we tried to identify the roles and mechanisms of interferon regulatory factor 7 (IRF7) in modulating the phenotypes of macrophages in lipopolysaccharide (LPS)-induced intestinal inflammation. The mouse model of intestinal inflammation was induced by lipopolysaccharide (LPS), and mouse bone marrow-derived macrophages (BMDMs) and mouse intestinal epithelial cells were selected for experimental verification in vitro. Results demonstrated that IRF7 was highly expressed in the mouse model of intestinal inflammation, while IRF7 deficiency repressed macrophage M1 polarization and attenuated intestinal inflammation in mice. p65 and SET domain bifurcated 1 (SETDB1) synergistically promoted histone 3 lysine 4 trimethylation (H3K4me3) methylation to elevate IRF7 expression, which activated the Nod-like receptor (NLR) pathway to induce macrophage M1 polarization. Through this mechanism, IRF7 in BMDMs functioned to accelerate intestinal epithelial cell apoptosis and their release of pro-inflammatory proteins. Furthermore, the promoting effect of p65 and SETDB1 on LPS-induced intestinal inflammation was validated in vivo. To sum up, NF-κB p65 and SETDB1 facilitated IRF7-mediated macrophage M1 polarization, thereby aggravating the LPS-induced intestinal inflammation. Hence, this study highlights the appealing value of these factors as anti-inflammatory targets.

Inhibition of Checkpoint Kinase 1 (CHK1) Upregulates Interferon Regulatory Factor 1 (IRF1) to Promote Apoptosis and Activate Anti-Tumor Immunity via MICA in Hepatocellular Carcinoma (HCC).

CHK1 is considered a key cell cycle checkpoint kinase in DNA damage response (DDR) pathway to communicate with several signaling pathways involved in the tumor microenvironment (TME) in numerous cancers. However, the mechanism of CHK1 signaling regulating TME in hepatocellular carcinoma (HCC) remains unclear. CHK1 expression in HCC tissue was determined by IHC staining assay. DNA damage and apoptosis in HCC cells induced by cisplatin or CHK1 inhibition were detected by WB and flow cytometry. The interaction of CHK1 and IRF1 was analyzed by single-cell RNA-sequence, WB, and immunoprecipitation assay. The mechanism of IRF1 regulating MICA was investigated by ChIP-qPCR. CHK1 expression is upregulated in human HCC tumors compared to the background liver. High CHK1 mRNA level predicts advanced tumor stage and worse prognosis. Cisplatin and CHK1 inhibition augment cellular DNA damage and apoptosis. Overexpressed CHK1 suppresses IRF1 expression through proteolysis. Furthermore, single-cell RNA-sequence analyses confirmed that MICA expression positively correlated with IRF1 in HCC cells. Immunoprecipitation assay showed the binding between CHK1 and IRF1. Cisplatin and CHK1 inhibition upregulate MICA expression through IRF1-mediated transcriptional effects. A novel specific cis-acting IRF response element was identified at -1756 bp in the MICA promoter region that bound IRF1 to induce MICA gene transcription. MICA may increase NK cell and CD8+T cell infiltration in HCC. DNA damage regulates the interaction of CHK1 and IRF1 to activate anti-tumor immunity via the IRF1-MICA pathway in HCC.

Identification of IRF-associated molecular subtypes in clear cell renal cell carcinoma to characterize immunological characteristics and guide therapy.

Recently studies have identified a critical role for interferon regulatory factor (IRF) in modulating tumour immune microenvironment (TME) infiltration and tumorigenesis. Based on IRF1-9 expression profiles, we classified all ccRCC samples into three molecular subtypes (clusters A-C) and characterized the prognosis and immune infiltration of these clusters. IRFscore constructed by principal component analysis was performed to quantify IRF-related subtypes in individual patients. We proved that IRFscore predicted multiple patient characteristics, with high IRFscore group having poorer prognosis, suppressed TME, increased T-cell exhaustion, increased TMB and greater sensitivity to anti- PD-1/CTLA-4 therapies. Furthermore, analysis of metastatic ccRCC (mccRCC) molecular subtypes and drug sensitivity proved that low IRFscore was more sensitive to targeted therapies. Moreover, IRFscore grouping can be well matched to the immunological and molecular typing of ccRCC. qRT-PCR showed differential expression of IRFs in different cell lines. Evaluating IRF-related molecular subtypes in individual ccRCC patients not only facilitates our understanding of tumour immune infiltration, but also provides more effective clinical ideas for personalised treatment.

IRF8 Regulates Intrinsic Ferroptosis through Repressing p53 Expression to Maintain Tumor Cell Sensitivity to Cytotoxic T Lymphocytes.

Ferroptosis has emerged as a cytotoxic T lymphocyte (CTL)-induced tumor cell death pathway. The regulation of tumor cell sensitivity to ferroptosis is incompletely understood. Here, we report that interferon regulatory factor 8 (IRF8) functions as a regulator of tumor cell intrinsic ferroptosis. Genome-wide gene expression profiling identified the ferroptosis pathway as an IRF8-regulated pathway in tumor cells. IRF8.KO tumor cells acquire resistance to intrinsic ferroptosis induction and IRF8-deficient tumor cells also exhibit decreased ferroptosis in response to tumor-specific CTLs. Irf8 deletion increased p53 expression in tumor cells and knocking out p53 in IRF8.KO tumor cells restored tumor cell sensitivity to intrinsic ferroptosis induction. Furthermore, IRF8.KO tumor cells grew significantly faster than WT tumor cells in immune-competent mice. To restore IRF8 expression in tumor cells, we designed and synthesized codon usage-optimized IRF8-encoding DNA to generate IRF8-encoding plasmid NTC9385R-mIRF8. Restoring IRF8 expression via a lipid nanoparticle-encapsulated NTC9385R-mIRF8 plasmid therapy suppressed established tumor growth in vivo. In human cancer patients, nivolumab responders have a significantly higher IRF8 expression level in their tumor cells as compared to the non-responders. Our data determine that IRF8 represses p53 expression to maintain tumor cell sensitivity to intrinsic ferroptosis.

Continuous Expression of Interferon Regulatory Factor 4 Sustains CD8+ T Cell Immunity against Tumor.

T-cell-based immunotherapy is gaining momentum in cancer treatment; however, our comprehension of the transcriptional regulation governing T cell antitumor activity remains constrained. The objective of this study was to explore the function of interferon regulatory factor 4 (IRF4) in antitumor CD8+ T cells using the TRAMP-C1 prostate cancer and B16F10 melanoma model. To achieve this, we generated an Irf4GFP-DTR mouse strain and discovered that CD8+ tumor-infiltrating lymphocytes (TILs) expressing high levels of IRF4.GFP exhibited a more differentiated PD-1high cell phenotype. By administering diphtheria toxin to tumor-bearing Irf4GFP-DTR mice, we partially depleted IRF4.GFP+ TILs and observed an accelerated tumor growth. To specifically explore the function of IRF4 in antitumor CD8+ T cells, we conducted 3 adoptive cell therapy (ACT) models. Firstly, depleting IRF4.GFP+ CD8+ TILs derived from ACT significantly accelerated tumor growth, emphasizing their crucial role in controlling tumor progression. Secondly, deleting the Irf4 gene in antitumor CD8+ T cells used for ACT led to a reduction in the frequency and effector differentiation of CD8+ TILs, completely abolishing the antitumor effects of ACT. Lastly, we performed a temporal deletion of the Irf4 gene in antitumor CD8+ T cells during ACT, starting from 20 days after tumor implantation, which significantly compromised tumor control. Therefore, sustained expression of IRF4 is essential for maintaining CD8+ T cell immunity in the melanoma model, and these findings carry noteworthy implications for the advancement of more potent immunotherapies for solid tumors.

The dynamic functions of IRF4 in B cell malignancies.

The trajectory of B cell development goes through subsequent steps governed by complex genetic programs, strictly regulated by multiple transcription factors. Interferon regulatory factor 4 (IRF4) regulates key points from pre-B cell development and receptor editing to germinal center formation, class-switch recombination and plasma cell differentiation. The pleiotropic ability of IRF4 is mediated by its "kinetic control", allowing different IRF4 expression levels to activate distinct genetic programs due to modulation of IRF4 DNA-binding affinity. IRF4 is implicated in B cell malignancies, acting both as tumor suppressor and as tumor oncogene in different types of precursors and mature B cell neoplasia. Here, we summarize the complexity of IRF4 functions related to different DNA-binding affinity, multiple IRF4-specific target DNA motif, and interactions with transcriptional partners. Moreover, we describe the unique role of IRF4 in acute leukemias and B cell mature neoplasia, focusing on pathogenetic implications and possible therapeutic strategies in multiple myeloma and chronic lymphocytic leukemia.

T-box transcription factor 2 mediates antitumor immune response in cutaneous squamous cell carcinoma by regulating the expression of programmed death ligand 1.

Cutaneous squamous cell carcinoma (CSCC) is the second largest nonmelanoma skin cancer in humans; effective treatment options for metastatic CSCC are still in short. In this study, we aimed to explore the function of T-box transcription factor 2 (TBX2) in CSCC. The expression level of TBX2 was determined in CSCC samples and cell lines. Programmed death ligand 1 (PD-L1) expression was also analyzed in human CSCC samples. Furthermore, SCC13 cells were transfected with TBX2-DN (loss of function) or normal TBX2 to check its role in regulating PD-L1. The expression level of TBX2 was positively correlated with the stage of CSCC. CSCC tumor cell lines have significantly higher expression levels of TBX2 than normal skin cell lines, and SCC13 cells showed the highest expression. PD-L1 expressions were upregulated during the progression of CSCC, and positively correlated with TBX2. Furthermore, PD-L1 expression increased in SCC13 cells overexpressing TBX2. However, TBX2 did not regulate the activation of IFNγ signal, but mediated the expression of interferon regulatory factor 1 (IRF1) and PD-L1 in both SCC13 and PDV cells. TBX2 could mediate antitumor immune response in CSCC by regulating the expression of PD-L1 through IRF1. It might be a prognostic marker in CSCC and synergistic target for PD-1 immunotherapy.

Silencing of IRF8 Mediated by m6A Modification Promotes the Progression of T-Cell Acute Lymphoblastic Leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with a poor prognosis, urging for novel therapeutic targets and treatment strategies. N6-methyladenosine (m6A) is a crucial methylation modification that affects the pathogenesis of leukemia by regulating the mRNA of key genes. Interferon regulatory factor 8 (IRF8) is a crucial transcription factor for hematological lineage commitment, but its role in T-ALL is unclear. Here, IRF8 is shown to suppress T-ALL. The expression of IRF8 is abnormally silenced in patients with T-ALL. Knockout of Irf8 significantly hastens the progression of Notch1-induced T-ALL in vivo. Overexpression of IRF8 suppresses the proliferation and invasion of T-ALL cells by inhibiting the phosphatidylinositol 3-kinase/AKT signaling pathway. The fat mass- and obesity-associated protein (FTO), an m6A demethylase, is responsible for directly binding to m6A sites in 3' untranslated region of IRF8 messenger RNA (mRNA) and inducing mRNA degradation via m6A modification. Targeting the FTO-IRF8 axis is used as a proof of concept therapy; inhibition of FTO's demethylase activity drastically alleviates the proliferation of leukemic cells and prolongs the survival of T-ALL mice by restoring IRF8 expression. This study elucidates the pathogenesis of T-ALL from the perspective of epitranscriptomics and provides new insight into the genetic mechanisms and targeted therapy of T-ALL.

Nebulized Mycobacterium vaccae protects against asthma by attenuating the imbalance of IRF4/IRF8 expression in dendritic cells

Objective: To assess the effects of nebulized inhaled Mycobacterium vaccae on allergic airway inflammation, airway hyperresponsiveness, and Th1/Th2 cell imbalance in mice with ovalbumin (OVA)-induced asthma. Methods: Mice received OVA sensitization and challenge for establishment of the asthmatic model. For intervention, mice received Mycobacterium vaccae nebulization once every other day from the first day of sensitization to the day before challenge. After challenge, pulmonary histological analysis and airway responsiveness measurement were performed. In addition, Th1/Th2 cytokines and OVA-specific IgE levels in bronchoalveolar lavage fluid were measured by ELISA. Th1/Th2 subset ratios and the expression of interferon-regulatory factor 4 (IRF4), IRF8 and Toll-like receptor 4 (TLR4) in dendritic cells were evaluated by flow cytometry. Results: Severe inflammatory infiltration and airway hyperresponsiveness were observed in OVA-induced asthmatic mice. Asthmatic mice showed higher Th2 cytokine concentration and increased percentage of Th2 cells, along with lower Th1 cytokine concentration and reduced percentage of Th1 cells compared with the normal control. Moreover, an imbalance of IRF4+ and IRF8+ in dendritic cells was found in asthmatic mice. Nebulized inhaled Mycobacterium vaccae reduced airway hyperresponsiveness and inflammation in OVA-induced asthmatic mice. In addition, nebulized inhaled Mycobacterium vaccae enhanced TLR4 and IRF8 expression, and alleviated the imbalance of Th1/Th2 as well as IRF4+ and IRF8+ in dendritic cells. Conclusions: Nebulized inhaled Mycobacterium vaccae protects against asthma by alleviating the imbalance of Th1/Th2 and IRF4/ IRF8 in OVA-induced asthmatic mice.

Duck Enteritis Virus Inhibits the cGAS-STING DNA-Sensing Pathway To Evade the Innate Immune Response.

Cyclic GMP-AMP synthase (cGAS), a key DNA sensor, detects cytosolic viral DNA and activates the adaptor protein stimulator of interferon genes (STING) to initiate interferon (IFN) production and host innate antiviral responses. Duck enteritis virus (DEV) is a duck alphaherpesvirus that causes an acute and contagious disease with high mortality in waterfowl. In the present study, we found that DEV inhibits host innate immune responses during the late phase of viral infection. Furthermore, we screened DEV proteins for their ability to inhibit the cGAS-STING DNA-sensing pathway and identified multiple viral proteins, including UL41, US3, UL28, UL53, and UL24, which block IFN-β activation through this pathway. The DEV tegument protein UL41, which exhibited the strongest inhibitory effect, selectively downregulated the expression of interferon regulatory factor 7 (IRF7) by reducing its mRNA accumulation, thereby inhibiting the DNA-sensing pathway. Ectopic expression of UL41 markedly reduced viral DNA-triggered IFN-β production and promoted viral replication, whereas deficiency of UL41 in the context of DEV infection increased the IFN-β response to DEV and suppressed viral replication. In addition, ectopic expression of IRF7 inhibited the replication of the UL41-deficient virus, whereas IRF7 knockdown facilitated its replication. This study is the first report identifying multiple viral proteins encoded by a duck DNA virus, which inhibit the cGAS-STING DNA-sensing pathway. These findings expand our knowledge of DNA sensing in ducks and reveal a mechanism through which DEV antagonizes the host innate immune response. IMPORTANCE Duck enteritis virus (DEV) is a duck alphaherpesvirus that causes an acute and contagious disease with high mortality, resulting in substantial economic losses in the commercial waterfowl industry. The evasion of DNA-sensing pathway-mediated antiviral innate immunity is essential for the persistent infection and replication of many DNA viruses. However, the mechanisms used by DEV to modulate the DNA-sensing pathway remain poorly understood. In the present study, we found that DEV encodes multiple viral proteins to inhibit the cGAS-STING DNA-sensing pathway. The DEV tegument protein UL41 selectively diminished the accumulation of interferon regulatory factor 7 (IRF7) mRNA, thereby inhibiting the DNA-sensing pathway. Loss of UL41 potently enhanced the IFN-β response to DEV and impaired viral replication in ducks. These findings provide insights into the host-virus interaction during DEV infection and help develop new live attenuated vaccines against DEV.

Negative Modulation of B Cell Activation by Melanocortin 1 Receptor Signaling Protects against Membranous Nephropathy.

Emerging evidence suggests that melanocortin neuropeptides-specifically adrenocorticotropic hormone-offer a novel, steroidogenic-independent therapeutic modality for membranous nephropathy (MN). The molecular mechanism underlying this beneficial effect, however, remains largely elusive. To investigate whether melanocortins modulate humoral immunity, the authors induced passive Heymann nephritis, a model of human MN, in wild-type and melanocortin 1 receptor (MC1R) knockout rats and treated them with melanocortin agents. Additional rats received adoptive transfer of bone marrow-derived cells beforehand from wild-type or MC1R knockout rats. The findings indicate that MC1R signaling plays a key role in negative modulation of B-cell activation and thereby suppresses humoral immune responses in passive Heymann nephritis, and suggest that MC1R signaling might offer a novel B cell-targeted therapeutic strategy for MN. Emerging evidence suggests that the pituitary neuropeptide melanocortins-specifically, adrenocorticotropic hormone-offer a novel nonsteroidogenic therapeutic modality for membranous nephropathy (MN). However, the mechanism(s) of action remains elusive. To investigate whether melanocortins modulate humoral immunity, we induced passive Heymann nephritis (PHN), a model of MN, in wild-type (WT) and melanocortin 1 receptor (MC1R) knockout (KO) rats. We treated the animals with melanocortin agents-repository corticotropin injection, the nonsteroidogenic pan-melanocortin receptor agonist [Nle 4 , DPhe 7 ]-α-melanocyte stimulating hormone, the selective MC1R agonist MS05, vehicle gel, or phosphate-buffered saline-and evaluated kidney function, histology, and molecular changes. Additional rats received adoptive transfer of syngeneic bone marrow-derived cells beforehand from WT or MC1R KO rats. KO of MC1R worsened PHN and this was associated with increased deposition of autologous immunoglobulin G (IgG) and complement C5b-9 in glomeruli and higher circulating levels of autologous IgG-evidence of a sensitized humoral immune response. Melanocortin therapy ameliorated PHN in WT rats, coinciding with reduced glomerular deposition of autologous IgG and C5b -9. The beneficial efficacy of melanocortins was blunted in KO rats but restored by adoptive transfer of syngeneic bone marrow-derived cells derived from WT rats. Mechanistically, MC1R was expressed in B lymphocytes and was negatively associated with B cell activation. MC1R agonism triggered the expression of microphthalmia-associated transcription factor in activated B cells in a cAMP-dependent mode and also repressed the expression of interferon regulatory factor 4 (a lymphoid transcription factor essential for B-cell development and maturation), resulting in suppressed plasma cell differentiation and IgG production. MC1R signaling negatively modulates B cell activation and suppresses humoral immune responses in PHN, suggesting that MC1R signaling might offer a novel therapeutic target for MN.

The Role of Interferon Regulatory Factor 1 in Regulating Microglial Activation and Retinal Inflammation.

Microglia are resident immune cells in the central nervous system (CNS). Microglial activation plays a prominent role in neuroinflammation and CNS diseases. However, the underlying mechanisms of microglial activation are not well understood. Here, we report that the transcription factor interferon regulatory factor 1 (IRF1) plays critical roles in microglial activation and retinal inflammation by regulating pro- and anti-inflammatory gene expression. IRF1 expression was upregulated in activated retinal microglia compared to those at the steady state. IRF1 knockout (KO) in BV2 microglia cells (BV2ΔIRF1) created by CRISPR/Cas9 genome-editing technique causes decreased microglia proliferation, migration, and phagocytosis. IRF1-KO decreased pro-inflammatory M1 marker gene expression induced by lipopolysaccharides (LPS), such as IL-6, COX-2, and CCL5, but increased anti-inflammatory M2 marker gene expression by IL-4/13, such as Arg-1, CD206, and TGF-β. Compared to the wild-type cells, microglial-conditioned media (MCM) of activated BV2ΔIRF1 cell cultures reduced toxicity or death to several retinal cells, including mouse cone photoreceptor-like 661 W cells, rat retinal neuron precursor R28 cells, and human ARPE-19 cells. IRF1 knockdown by siRNA alleviated microglial activation and retinal inflammation induced by LPS in mice. Together, the findings suggest that IRF1 plays a vital role in regulating microglial activation and retinal inflammation and, therefore, may be targeted for treating inflammatory and degenerative retinal diseases.

Analysis of COVID-19-Associated Proteins Identifies TANK-Binding Kinase 1 As an Immunotherapeutic Target in Multiple Myeloma

Background and Rationale. Patients with multiple myeloma (MM) are at a higher risk of viral infection due to immune deficiency, as recently highlighted by the severity of COVID-19 in MM patients. However, the mechanism(s) underlying the lack of anti-viral immune response in MM are unclear. We have previously shown that there are more plasmacytoid dendritic cells (pDCs) in the bone marrow of MM patients than in the bone marrow of healthy individuals and that these dysfunctional patient pDCs suppress T and NK cell-mediated immunity. Importantly, pDCs play a key role in both recognizing viral nucleic acid and initiating anti-viral immunity via type 1 interferon (IFN) response signaling. Therefore, we analyzed the immune-pathway proteins implicated in COVID-19-host interactions [COVID-19 protein interaction map, Gordon et al, Nature 2020; 583, 459-568] to assess whether pDC-MM interactions modulate these pathways to confer immune suppression and susceptibility to COVID-19. Results. We first assessed whether the expression of human genes involved in the COVID-19-host interaction changes when ex vivo MM cells are co-cultured with patient pDCs (compared to MM cells alone). We found that 41 of these genes were differentially expressed in MM cells when exposed to pDCs (log2Fold change: ± 3.5-fold; p < 0.00001), and this expression varied widely (median (log10): -0.13 to 4.5; adj p < 0.001). Three of these genes are linked to innate immunity and are essential for IFN production in MM cells - TBK1, IRF3 (Interferon regulatory factor 3), and RAE1 (interferon-inducible mRNA nuclear export factor). Importantly, pDCs downregulated the expression of TBK1 (Log2FC: -0.5) and RAE1 (Log2FC: -0.3) and upregulated the expression of IRF3 (Log2FC: 1.5) in MM cells after coculture (compared to MM cells alone, p < 0.0001). Concordantly, analysis of publicly available gene profiling datasets on relapsed MM patients showed low levels of TBK1 and RAE1 and higher levels of IRF3 (n = 50) (Log2FC: TBK1: -0.208; RAE1: -0.286; IRF3: 0.273; vs normal; p < 0.05). Of note, TBK1 expression was positively correlated with prognosis (n = 350, p = 0.026). We found that most of the 41 genes were also expressed in pDCs (NCBI GEO Datasets based on pDC cell line CAL1 and human peripheral blood pDCs). In unstimulated pDCs, TBK1 expression was significantly lower than IRF3 and RAE1 expression (2-3-fold, p < 0.05). Yet treating pDCs with CpG-ODN type-A, which induces IFN-α expression, increased both TBK1 (adj P = 0.004) and RAE1 (adj P = 0.043) expression, without significantly altering IRF3 expression. Finally, COVID-19 relies on the host ubiquitin-proteasome system for propagation, and we found that targeting ubiquitin receptor Rpn13 with the specific inhibitor RA190 restored TBK1 expression in MM cell lines, indicating the potential clinical use of targeting Rpn13 in restoring anti-viral immune responses in MM. Conclusion. Taken together, we show that TBK1 is downregulated in pDCs, and pDCs interacting with MM cells further decrease TBK1 expression in MM cells, thereby attenuating IFN-mediated anti-viral immune response signaling. Our findings suggest that: 1) low levels of TBK1 may confer increased susceptibility of MM patients to COVID-19 and 2) targeting TBK1 may restore the anti-viral immune response and reduce COVID-19 severity in MM.

IRF4 expression by lung dendritic cells drives acute but not Trm cell-dependent memory Th2 responses.

Expression of the transcription factor interferon regulatory factor 4 (IRF4) is required for the development of lung conventional DCs type 2 (cDC2s) that elicit Th2 responses, yet how IRF4 functions in lung cDC2s throughout the acute and memory allergic response is not clear. Here, we used a mouse model that loses IRF4 expression after lung cDC2 development to demonstrate that mice with IRF4-deficient DCs display impaired memory responses to allergen. This defect in the memory response was a direct result of ineffective Th2 induction and impaired recruitment of activated effector T cells to the lung after sensitization. IRF4-deficient DCs demonstrated defects in their migration to the draining lymph node and in T cell priming. Finally, T cells primed by IRF4-competent DCs mediated potent memory responses independently of IRF4-expressing DCs, demonstrating that IRF4-expressing DCs are not necessary during the memory response. Thus, IRF4 controlled a program in mature DCs governing Th2 priming and effector responses, but IRF4-expressing DCs were dispensable during tissue-resident memory T cell-dependent memory responses.

IRF4 Gene Expression on the Trail of Molecular Response: Looking at Chronic Myeloid Leukemia from Another Perspective

Introduction: Interferon regulatory factor 4 (IRF4) is a transcriptional factor with a key role in the modulation of inflammation and immune surveillance. The IRF4 gene is downregulated in Philadelphia-negative myeloproliferative neoplasms, and its expression is associated with prognosis and response to treatment. Methods: We evaluated the IRF4 expression kinetics during tyrosine kinase inhibitor (TKI) treatment in a cohort of 116 chronic myeloid leukemia (CML) patients to elucidate its role in the disease course. Results: A relationship between the IRF4 expression and the disease burden was observed at various disease stages. A correlation analysis between the International Scale (IS) and IRF4 values confirmed this close association. A significant increase is detected after 3 months of TKI treatment. Patients achieving an early molecular response (EMR) had higher IRF4 values at both diagnosis and after 3 months of therapy as compared to those failing the EMR target. Patients achieving treatment-free remission did not show IRF4 fluctuations during monitoring, while a decreased IRF4 expression emerged at the time of molecular relapse. Conclusion: Our data seem to confirm the relevance of IRF4 in the pathogenesis of CML, suggesting a pivotal role at the disease onset and a predictive value during the CML course.

Circ_0005615 contributes to the progression and Bortezomib resistance of multiple myeloma by sponging miR-185-5p and upregulating IRF4.

Circular RNAs (circRNAs) have been shown to play critical regulatory roles in multiple myeloma progression. Here, we aimed to explore the biologic role of circ_0005615 in multiple myeloma progression and its associated mechanism. Cell counting kit-8 assay was conducted to analyze the bortezomib resistance and proliferation of multiple myeloma cells. Cell proliferation was also analyzed by 5-Ethynyl-2'-deoxyuridine incorporation and flow cytometry assays. Cell apoptosis was assessed by flow cytometry. The interaction between microRNA-185-5p (miR-185-5p) and circ_0005615 or interferon regulatory factor 4 (IRF4) was verified by the dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. A xenograft tumor model was established in non-obese diabetic/server combined immune-deficiency mice to analyze the roles of circ_0005615 in tumor growth and bortezomib resistance. Circ_0005615 was upregulated in multiple myeloma tissues and cell lines. Circ_0005615 knockdown restrained the bortezomib resistance and proliferation and induced the apoptosis of multiple myeloma cells. Circ_0005615 acted as a molecular sponge for miR-185-5p, and the antitumor effects mediated by circ_0005615 knockdown were reversed by silencing miR-185-5p. IRF4 was confirmed as a direct target of miR-185-5p, and miR-185-5p overexpression-induced antitumor influences could be counteracted by IRF4 overexpression. Circ_0005615 could positively regulate IRF4 expression by sponging miR-185-5p in multiple myeloma cells. Circ_0005615 knockdown suppressed the growth and bortezomib resistance of xenograft tumors in vivo. Circ_0005615 contributed to the malignant progression and bortezomib resistance of multiple myeloma through mediating miR-185-5p/IRF4 signaling.

IRF8: Mechanism of Action and Health Implications.

Interferon regulatory factor 8 (IRF8) is a transcription factor of the IRF protein family. IRF8 was originally identified as an essentialfactor for myeloid cell lineage commitment and differentiation. Deletion of Irf8 leads to massive accumulation of CD11b+Gr1+ immature myeloid cells (IMCs), particularly the CD11b+Ly6Chi/+Ly6G− polymorphonuclear myeloid-derived suppressor cell-like cells (PMN-MDSCs). Under pathological conditions such as cancer, Irf8 is silenced by its promoter DNA hypermethylation, resulting in accumulation of PMN-MDSCs and CD11b+ Ly6G+Ly6Clo monocytic MDSCs (M-MDSCs) in mice. IRF8 is often silenced in MDSCs in human cancer patients. MDSCs are heterogeneous populations of immune suppressive cells that suppress T and NK cell activity to promote tumor immune evasion and produce growth factors to exert direct tumor-promoting activity. Emerging experimental data reveals that IRF8 is also expressed in non-hematopoietic cells. Epithelial cell-expressed IRF8 regulates apoptosis and represses Osteopontin (OPN). Human tumor cells may use the IRF8 promoter DNA methylation as a mechanism to repress IRF8 expression to advance cancer through acquiring apoptosis resistance and OPN up-regulation. Elevated OPN engages CD44 to suppress T cell activation and promote tumor cell stemness to advance cancer. IRF8 thus is a transcription factor that regulates both the immune and non-immune components in human health and diseases.

A Comprehensive Analysis of Interferon Regulatory Factor Expression: Correlation with Immune Cell Infiltration and Patient Prognosis in Endometrial Carcinoma

As a family of transcription factors, the correlations between expression pattern of nine interferon regulatory factor (IRF) family members, the immune invasion pattern, and the associated patient survival rate in endometrial carcinoma (EC) remain to be elucidated. Based on The Cancer Genome Atlas (TCGA), the expression profiles of the high and low IRF mRNA expression groups were analyzed using R (3.6.3) statistical software. Gene annotation and pathway analyses were performed using Metascape. GSEA was performed using the R package clusterProfiler (3.6.3). The single-sample gene set enrichment analysis (ssGSEA) was used to quantify the relative tumor infiltration levels of immune cell types. Immunohistochemistry data provided by HPA database was used to study the expression of the IRF proteins. Using the GEPIA dataset, the correlation between the expression of IRFs and the tumor stage of EC was analyzed. The correlations between the different IRFs were analyzed using cBioPortal. The expression of IRF2, IRF3, IRF5, IRF6, IRF7, IRF8, and IRF9 was different when comparing EC and normal endometrial samples. IRF2, IRF6, IRF7, and IRF8 were indicated to be potential diagnostic markers for EC. In combination with receiver operating characteristic analysis results, IRF2, IRF6, IRF7, and IRF8 were indicated to be potential diagnostic markers for EC. Levels of individual IRFs were associated with alternate outcomes, with the expression of IRF3 being correlated with the stage of EC and high expression of IRF4 being positively correlated with overall survival (OS); conversely, high expression of IRF5 was negatively correlated with OS. Additionally, high expression levels of both IRF2 and IRF4 were positively correlated with the disease-specific survival rate, and high expression of IRF4 was positively correlated with the progression-free interval. These data suggest a role for IRF2, IRF4, and IRF5 in the prognosis of EC. The expression of IRFs is associated with immune infiltration.

Exploration of mechanism of "simultaneous treatment of brain and heart" of Naoxintong Capsules based on Toll-like receptor signaling pathway

This study aims to explore the mechanism of &quot;simultaneous treatment of the brain and the heart&quot; of Naoxintong Capsules(NXT) under cerebral ischemia based on Toll-like receptor(TLR) signaling pathway.Male SD rats were randomized into sham operation group, model group, NXT group, and positive drug group.Middle cerebral artery occlusion(MCAO) model rats were used in model group, NXT group, and positive drug group, respectively.Neurological function was scored with the Bederson scale, and brain infarct rate was measured by 2,3,5-triphenyltetrazolium chloride(TTC) staining.Brain edema was detected with wet-dry weight method.Hematoxylin-eosin(HE) staining and TdT-mediated dUTP nick-end labeling(TUNEL) staining were used to observe and count apoptotic cardiocytes.In addition, serum myocardial enzymes were measured.The expression of 8 TLR signaling pathway-related proteins interferon-α(IFN-α), interferon regulatory factor-3(IRF3), interferon regulatory factor-7(IRF7), TLR2, TLR4, TLR7, TLR9, and tumor necrosis factor-α(TNF-α) in the cerebral cortex and heart of rats was detected by Western blot. Brain infarct rate, neurological function score, and brain water content in NXT group decreased significantly compared with those in the model group. At the same time, the reduction in apoptosis rate of cardiocytes and the content of serum aspartate aminotransferase(AST), alanine aminotransferase(ALT), creatine kinase(CK), and lactate dehydrogenase(LDH) were decreased in the NXT group.Systems pharmacological results and previous research showed that TLR signaling pathway played an important role in immune inflammatory response.The study of TLR signaling pathway and related proteins is helpful to elucidate the mechanism of &quot;simultaneous treatment of the brain and the heart&quot;. Western blot results showed that NXT significantly inhibited the expression of IRF3, IRF7, TLR2, TLR7, and TNF-α in cerebral cortex and heart under cerebral ischemia.Cerebral ischemia influences cardiac functions, and TLR signaling pathway is one of the pathways for &quot;simultaneous treatment of the brain and the heart&quot; of NXT.

IRF8 deficiency induces the transcriptional, functional, and epigenetic reprogramming of cDC1 into the cDC2 lineage

Conventional dendritic cells (cDCs) consist of two major functionally and phenotypically distinct subsets, cDC1 and cDC2, whose development is dependent on distinct sets of transcription factors. Interferon regulatory factor 8 (IRF8) is required at multiple stages of cDC1 development, but its role in committed cDC1 remains unclear. Here, we used Xcr1-cre to delete Irf8 in committed cDC1 and demonstrate that Irf8 is required for maintaining the identity of cDC1. In the absence of Irf8, committed cDC1 acquired the transcriptional, functional, and chromatin accessibility properties of cDC2. This conversion was independent of Irf4 and was associated with the decreased accessibility of putative IRF8, Batf3, and composite AP-1-IRF (AICE)-binding elements, together with increased accessibility of cDC2-associated transcription-factor-binding elements. Thus, IRF8 expression by committed cDC1 is required for preventing their conversion into cDC2-like cells.