Competition between two HUSH complexes orchestrates the immune response to retroelement invasion.

The human silencing hub (HUSH) preserves genome integrity through the epigenetic repression of invasive genetic elements. However, despite our understanding of HUSH as an obligate complex of three subunits, only loss of MPP8 or Periphilin, but not TASOR, triggers interferon signaling following derepression of endogenous retroelements. Here, we resolve this paradox by characterizing a second HUSH complex that shares MPP8 and Periphilin but assembles around TASOR2, an uncharacterized paralog of TASOR. Whereas HUSH represses LINE-1 retroelements marked by the repressive histone modification H3K9me3, HUSH2 is recruited by the transcription factor IRF2 to repress interferon-stimulated genes. Mechanistically, HUSH-mediated retroelement silencing sequesters the limited pool of the shared subunits MPP8 and Periphilin, preventing TASOR2 from forming HUSH2 complexes and hence relieving the HUSH2-mediated repression of interferon-stimulated genes. Thus, competition between two HUSH complexes intertwines retroelement silencing with the induction of an immune response, coupling epigenetic and immune aspects of genome defense.

The transcription factor IRF2 drives interferon-mediated CD8+ T cell exhaustion to restrict anti-tumor immunity.

Type I and II interferons (IFNs) stimulate pro-inflammatory programs that are critical for immune activation, but also induce immune-suppressive feedback circuits that impede control of cancer growth. Here, we sought to determine how these opposing programs are differentially induced. We demonstrated that the transcription factor interferon regulatory factor 2 (IRF2) was expressed by many immune cells in the tumor in response to sustained IFN signaling. CD8+ T cell-specific deletion of IRF2 prevented acquisition of the T cell exhaustion program within the tumor and instead enabled sustained effector functions that promoted long-term tumor control and increased responsiveness to immune checkpoint and adoptive cell therapies. The long-term tumor control by IRF2-deficient CD8+ T cells required continuous integration of both IFN-I and IFN-II signals. Thus, IRF2 is a foundational feedback molecule that redirects IFN signals to suppress T cell responses and represents a potential target to enhance cancer control.

Bcl6, Irf2, and Notch2 promote nonclassical monocyte development.

Ly6Clo monocytes are a myeloid subset that specializes in the surveillance of vascular endothelium. Ly6Clo monocytes have been shown to derive from Ly6Chi monocytes. NOTCH2 signaling has been implicated as a trigger for Ly6Clo monocyte development, but the basis for this effect is unclear. Here, we examined the impact of NOTCH2 signaling of myeloid progenitors on the development of Ly6Clo monocytes in vitro. NOTCH2 signaling induced by delta-like ligand 1 (DLL1) efficiently induced the transition of Ly6Chi TREML4- monocytes into Ly6Clo TREML4+ monocytes. We further identified two additional transcriptional requirements for development of Ly6Clo monocytes. Deletion of BCL6 from myeloid progenitors abrogated development of Ly6Clo monocytes. IRF2 was also required for Ly6Clo monocyte development in a cell-intrinsic manner. DLL1-induced in vitro transition into Ly6Clo TREML4+ monocytes required IRF2 but unexpectedly could occur in the absence of NUR77 or BCL6. These results imply a transcriptional hierarchy for these factors in controlling Ly6Clo monocyte development.

Mesenchymal stem cells (MSCs) from the mouse bone marrow show differential expression of interferon regulatory factors IRF-1 and IRF-2.

BACKGROUND: Interferon regulatory factors (IRF-1 and IRF-2) are transcription factors widely implicated in various cellular processes, including regulation of inflammatory responses to pathogens, cell proliferation, oncogenesis, differentiation, autophagy, and apoptosis. METHODS: We have studied the expression of IRF-1, IRF-2 mRNAs by RT-PCR, cellular localization of the proteins by immunofluorescence, and expression of mRNAs of genes regulated by IRF-1, IRF-2 by RT-PCR in mouse bone marrow cells (BMCs) and mesenchymal stem cells (MSCs). RESULTS: Higher level of IRF-1 mRNA was observed in BMCs and MSCs compared to that of IRF-2. Similarly, differential expression of IRF-1 and IRF-2 proteins was observed in BMCs and MSCs. IRF-1 was predominantly localized in the cytoplasm, whereas IRF-2 was localized in the nuclei of BMCs. MSCs showed nucleo-cytoplasmic distribution of IRF-1 and nuclear localization of IRF-2. Constitutive expression of IRF-1 and IRF-2 target genes: monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase-2 (COX-2), matrix metalloproteinase-9 (MMP-9), and caspase-1 was observed in both BMCs and MSCs. MSCs showed constitutive expression of the pluripotency-associated factors, Oct3/4 and Sox-2. Lipopolysaccharide (LPS)-treatment of MSCs induced prominent cellular localization of IRF-1 and IRF-2. CONCLUSIONS: Our results suggest that IRF-1 and IRF-2 exhibit differential expression of their mRNAs and subcellular localization of the proteins in BMCs and MSCs. These cells also show differential levels of constitutive expression of IRF-1 and IRF-2 target genes. This may regulate immune-responsive properties of BMCs and MSCs through IRF-1, IRF-2-dependent gene expression and protein-protein interaction. Regulating IRF-1 and IRF-2 may be helpful for immunomodulatory functions of MSCs for cell therapy and regenerative medicine.

Expanding the phenotype of NEDAMSS with a psychiatric perspective: analysis of a new case, and a systematic review of the literature.

Pathogenic variants in the IRF2BPL gene are associated with neurodevelopmental disorders with varying degrees of regression, loss of speech and epilepsy. The phenotype is also known as Neurodevelopmental Disorder with regression, Abnormal Movements, loss of Speech, and Seizures (NEDAMSS). The motor symptoms of this disorder share significant phenotypical characteristics with catatonia, a severe neuropsychiatric psychomotor syndrome. The objective of this article is to expand the knowledge on the presentation of NEDAMSS with a focus on psychiatric symptoms including catatonia. A systematic review of 32 case presentations of NEDAMSS, and a novel case report of a patient with NEDAMSS, exhibiting multiple psychiatric symptoms, including catatonia are presented. Psychiatric symptoms and disorders including affective disorders, psychotic symptoms, catatonia, and developmental disorders are reported in one third of the reviewed cases. Reported effects of pharmacological treatment on motor symptoms of NEDAMSS are very limited. Our case presents improvement in motor symptoms originally attributed to NEDAMSS, after treatment with Lorazepam following diagnosis with catatonia. Patients with NEDAMSS may present with both neurological and psychiatric symptoms. The clinical presentation of NEDAMSS motor symptoms and catatonia have similarities and thus poses significant challenges to the diagnostic process, with risk of incorrect or delayed treatment. The limited experience and the complex phenotype of NEDAMSS complicates pharmacological treatment and encourages caution, especially with the use of antipsychotic drugs in the presence of possible catatonic symptoms.

A novel IRF2BP2::CDX2 Gene fusion in digital intravascular myoepithelioma of soft tissue: An enigma!

Soft tissue myoepitheliomas (STM) are benign myoepithelial neoplasms (of nonsalivary gland origin) arising, most commonly within subcutaneous and deep soft tissues of the extremities and rarely within bones. To the best of our knowledge, the intravascular location of STM as well as the identification of a novel IRF2BP2::CDX2 fusion have not been previously reported. Herein, we report a case of spindle cell myoepithelioma arising within the intravascular space of the right index finger in a 52-year-old male of more than 20 years duration. Histopathology demonstrated an intravascular tumefactive lesion composed of predominantly plump banal spindle cells in a fascicular arrangement within a mixed collagenous and chondromyxoid stroma colliding with papillary endothelial hyperplasia (Masson tumor). By immunohistochemistry, the lesional cells were positive for keratin-AE1/3, epithelial membrane antigen, S100, SOX10, glial fibrillary acid protein, calponin and negative for CD34, smooth muscle actin, desmin, p63, and ERG. Fluorescence in situ hybridization for EWSR1 gene rearrangement was negative. Next-generation sequencing detected a novel IRF2BP2::CDX2 fusion involving Exon 1 of the IRF2BP2 gene and Exon 2 of the CDX2 gene confirmed by reverse transcriptase polymerase chain reaction and Sanger sequencing. Further, clinical evaluation for a salivary gland mass in the head and neck region and magnetic resonance imaging (MRI) of the chest, abdomen, and pelvis was performed with no evidence of tumor elsewhere. Taken together, the overall features were considered diagnostic of STM. Our current case underscores the novelty of the IRF2BP2::CDX2 gene fusion in STM and its exceptionally rare intravascular location.

IRF2 Cooperates with Phosphoprotein of Spring Viremia of Carp Virus to Suppress Antiviral Response in Zebrafish.

IFN regulatory factor (IRF) 2 belongs to the IRF1 subfamily, and its functions are not yet fully understood. In this study, we showed that IRF2a was a negative regulator of the interferon (IFN) response induced by spring viremia of carp virus (SVCV). Irf2a-/- knockout zebrafish were less susceptible to SVCV than wild-type fish. Transcriptomic analysis reveals that differentially expressed genes (DEGs) in the irf2a-/- and irf2a+/+ cells derived caudal fins were mainly involved in cytokine-cytokine receptor interaction, mitogen-activated protein kinase (MAPK) signaling pathway, and transforming growth factor-beta (TGF-beta) signaling pathway. Interestingly, the basal expression levels of interferon stimulating genes (ISGs), including pkz, mx, apol, and stat1 were higher in the irf2a-/- cells than irf2a+/+ cells, suggesting that they may contribute to the increased viral resistance of the irf2a-/- cells. Overexpression of IRF2a inhibited the activation of ifnφ1 and ifnφ3 induced by SVCV and poly(I:C) in the epithelioma papulosum cyprini (EPC) cells. Further, it was found that SVCV phosphoprotein (SVCV-P) could interact with IRF2a to promote IRF2a nuclear translocation and protein stability via suppressing K48-linked ubiquitination of IRF2a. Both IRF2a and SVCV-P not only destabilized STAT1a but reduced its translocation into the nucleus. Our work demonstrates that IRF2a cooperates with SVCV-P to suppress host antiviral response against viral infection in zebrafish. IMPORTANCE Interferon regulatory factors (IRFs) are central in the regulation of interferon-mediated antiviral immunity. Here, we reported that IRF2a suppressed interferon response and promoted virus replication in zebrafish. The suppressive effects were enhanced by the phosphoprotein of the spring viremia of carp virus (SVCV) via inhibition of K48-linked ubiquitination of IRF2a. IRF2a and SVCV phosphoprotein cooperated to degrade STAT1 and block its nuclear translocation. Our work demonstrated that IRFs and STATs were targeted by the virus through posttranslational modifications to repress interferon-mediated antiviral response in lower vertebrates.

Novel mutation and expanding phenotype in IRF2BP2 deficiency.

OBJECTIVES: Inborn errors of immunity manifest with susceptibility to infection but may also present with immune dysregulation only. According to the European Society for Immunodeficiencies Registry about 50% of inborn errors of immunity are classified as common variable immunodeficiencies (CVID). In only few CVID patients are monogenic causes identified. IFN regulatory factor-2 binding protein 2 (IRF2BP2) is one of 20 known genes associated with CVID phenotypes and has only been reported in two families so far. We report another IRF2BP2-deficient patient with a novel pathogenic variant and phenotype and characterize impaired B cell function and immune dysregulation. METHODS: We performed trio whole-exome sequencing, determined B cell subpopulations and intracellular calcium mobilization upon B cell receptor crosslinking in B cells. T cell subpopulations, T cell proliferation and a type I IFN signature were measured. Colonoscopy and gastroduodenoscopy including histopathology were performed. RESULTS: The 33-year-old male presented with recurrent respiratory infections since childhood, colitis and RA beginning at age 25 years. We identified a novel de novo nonsense IRF2BP2 variant c.1618C>T; p.(Q540*). IgG deficiency was detected as consequence of a severe B cell differentiation defect. This was confirmed by impaired plasmablast formation upon stimulation with CpG. No serum autoantibodies were detected. Intracellular cytokine production in CD4+ T cells and CTLA4 expression on FOXP3+ Tregs were impaired. Type I IFN signature was elevated. CONCLUSION: The identified loss-of-function variant in IRF2BP2 severely impairs B cell development and T cell homeostasis, and may be associated with colitis and RA. Our results provide further evidence for association of IRF2BP2 with CVID and contribute to the understanding of the underlying pathomechanisms.

IRF2BPL: A new genotype for progressive myoclonus epilepsies.

The progressive myoclonus epilepsies (PMEs) are a heterogeneous group of neurodegenerative disorders, typically presenting in late childhood. An etiologic diagnosis is achieved in about 80% of patients with PME, and genome-wide molecular studies on remaining, well-selected, undiagnosed cases can further dissect the underlying genetic heterogeneity. Through whole-exome sequencing (WES), we identified pathogenic truncating variants in the IRF2BPL gene in two, unrelated patients presenting with PME. IRF2BPL belongs to the transcriptional regulators family and it is expressed in multiple human tissues, including the brain. Recently missense and nonsense mutations in IRF2BPL were found in patients presenting with developmental delay and epileptic encephalopathy, ataxia, and movement disorders, but none with clear PME. We identified 13 other patients in the literature with myoclonic seizures and IRF2BPL variants. There was no clear genotype-phenotype correlation. With the description of these cases, the IRF2BPL gene should be considered in the list of genes to be tested in the presence of PME, in addition to patients with neurodevelopmental or movement disorders.

IRF2BPL as a novel causative gene for progressive myoclonus epilepsy.

IRF2BPL has recently been described as a novel cause of neurodevelopmental disorders with multisystemic regression, epilepsy, cerebellar symptoms, dysphagia, dystonia, and pyramidal signs. We describe a novel IRF2BPL phenotype consistent with progressive myoclonus epilepsy (PME) in three novel subjects and review the features of the 31 subjects with IRF2BPL-related disorders previously reported. Our three probands, aged 28-40 years, harbored de novo nonsense variants in IRF2BPL (c.370C > T, p.[Gln124*] and c.364C > T; p.[Gln122*], respectively). From late childhood/adolescence, they presented with severe myoclonus epilepsy, stimulus-sensitive myoclonus, and progressive cognitive, speech, and cerebellar impairment, consistent with a typical PME syndrome. The skin biopsy revealed massive intracellular glycogen inclusions in one proband, suggesting a similar pathogenic pathway to other storage disorders. Whereas the two older probands were severely affected, the younger proband had a milder PME phenotype, partially overlapping with some of the previously reported IRF2BPL cases, suggesting that some of them might be unrecognized PME. Interestingly, all three patients harbored protein-truncating variants clustered in a proximal, highly conserved gene region around the "coiled-coil" domain. Our data show that PME can be an additional phenotype within the spectrum of IRF2BPL-related disorders and suggest IRF2BPL as a novel causative gene for PME.

OIP5-AS1 Inhibits Oxidative Stress and Inflammation in Ischemic Stroke Through miR-155-5p/IRF2BP2 Axis.

BACKGROUND: Ischemic stroke is a very dangerous disease with high incidence, fatality and disability rate in human beings. Massive evidence has indicated that oxidative stress and inflammation are intimately correlated with progression of ischemic stroke. Additionally, LncRNAs were reported to be involved in ischemic stroke. Here, we aim to explore the effects and molecular mechanism of lncRNA OIP5-AS1 on oxidative stress and inflammation in ischemic stroke. METHODS: HMC3 and SH-SY5Y cells were under the condition of oxygen-glucose deprivation/reoxygenation (OGD/R) treatment to establish cell models of ischemic stroke. Commercial kits were employed to detect the indicators of oxidative stress including ROS, MDA and SOD. The expression of OIP5-AS1, miR-155-5p and IRF2BP2 mRNA was determined using RT-qPCR. The protein levels of inflammatory factors including TNF-α, IL-1ß and IL-6 and IRF2BP2 were assessed by western blot and/or ELISA. Luciferase activity assay was employed to validate their correlations among OIP5-AS1, miR-155-5p and IRF2BP2. RESULTS: In OGD/R-induced HMC3 and SH-SY5Y cells, the expression of OIP5-AS1 and IRF2BP2 was reduced while miR-155-5p was elevated. OGD/R induction promoted oxidative stress and inflammatory response in HMC3 and SH-SY5Y cells, while OIP5-AS1 or IRF2BP2 sufficiency as well as miR-155-5p inhibitor attenuated OGD/R-induced these influences. In addition, IRF2BP2 knockdown abolished the suppressive impacts of OIP5-AS1 overexpression on oxidative stress and inflammatory response in OGD/R-induced HMC3 and SH-SY5Y cells. Mechanistically, OIP5-AS1 enhanced IRF2BP2 expression via sponging miR-155-5p. CONCLUSION: OIP5-AS1 suppressed oxidative stress and inflammatory response to alleviate cell injury caused by OGD/R induction in HMC3 and SH-SY5Y cells through regulating miR-155-5p/IRF2BP2 axis, which might offer novel targeted molecules for ischemic stroke therapy.

Transient deSUMOylation of IRF2BP proteins controls early transcription in EGFR signaling.

Molecular switches are essential modules in signaling networks and transcriptional reprogramming. Here, we describe a role for small ubiquitin-related modifier SUMO as a molecular switch in epidermal growth factor receptor (EGFR) signaling. Using quantitative mass spectrometry, we compare the endogenous SUMO proteomes of HeLa cells before and after EGF stimulation. Thereby, we identify a small group of transcriptional coregulators including IRF2BP1, IRF2BP2, and IRF2BPL as novel players in EGFR signaling. Comparison of cells expressing wild type or SUMOylation-deficient IRF2BP1 indicates that transient deSUMOylation of IRF2BP proteins is important for appropriate expression of immediate early genes including dual specificity phosphatase 1 (DUSP1, MKP-1) and the transcription factor ATF3. We find that IRF2BP1 is a repressor, whose transient deSUMOylation on the DUSP1 promoter allows-and whose timely reSUMOylation restricts-DUSP1 transcription. Our work thus provides a paradigm how comparative SUMO proteome analyses serve to reveal novel regulators in signal transduction and transcription.

Agmatine-IRF2BP2 interaction induces M2 phenotype of microglia by increasing IRF2-KLF4 signaling.

BACKGROUND: Following central nervous system (CNS) injury, the investigation for neuroinflammation is vital because of its pleiotropic role in both acute injury and long-term recovery. Agmatine (Agm) is well known for its neuroprotective effects and anti-neuroinflammatory properties. However, Agm's mechanism for neuroprotection is still unclear. We screened target proteins that bind to Agm using a protein microarray; the results showed that Agm strongly binds to interferon regulatory factor 2 binding protein (IRF2BP2), which partakes in the inflammatory response. Based on these prior data, we attempted to elucidate the mechanism by which the combination of Agm and IRF2BP2 induces a neuroprotective phenotype of microglia. METHODS: To confirm the relationship between Agm and IRF2BP2 in neuroinflammation, we used microglia cell-line (BV2) and treated with lipopolysaccharide from Escherichia coli 0111:B4 (LPS; 20 ng/mL, 24 h) and interleukin (IL)-4 (20 ng/mL, 24 h). Although Agm bound to IRF2BP2, it failed to enhance IRF2BP2 expression in BV2. Therefore, we shifted our focus onto interferon regulatory factor 2 (IRF2), which is a transcription factor and interacts with IRF2BP2. RESULTS: IRF2 was highly expressed in BV2 after LPS treatment but not after IL-4 treatment. When Agm bound to IRF2BP2 following Agm treatment, the free IRF2 translocated to the nucleus of BV2. The translocated IRF2 activated the transcription of Kruppel-like factor 4 (KLF4), causing KLF4 to be induced in BV2. The expression of KLF4 increased the CD206-positive cells in BV2. CONCLUSIONS: Taken together, unbound IRF2, resulting from the competitive binding of Agm to IRF2BP2, may provide neuroprotection against neuroinflammation via an anti-inflammatory mechanism of microglia involving the expression of KLF4.

IRF2BPL gene variants with dystonia: one new Chinese case report.

BACKGROUND: The carriers of damaging heterozygous variants in interferon regulatory factor 2 binding protein-like (IRF2BPL), encoding a member of the IRF2BP family of transcriptional regulators, may be affected by a variety of neurological symptoms, such as neurodevelopmental regression, language and motor developmental delay, seizures, progressive ataxia and a lack of coordination, and even dystonia. CASE PRESENTATION: We report a Chinese boy who presented with dystonia, dysarthria, and normal development due to nonsense IRF2BPL mutation, with intact imaging and EEG findings but without developmental delays or seizures. Whole-exome sequencing revealed a novel nonsense variant IRF2BPL (NM_024496) Exon C.562C > T (p.Arg188*). CONCLUSION: This case report presents a Chinese boy with a novel nonsense variant in IRF2BPL, displaying rapid progressive dystonia and dysarthria, without early developmental delay or epilepsy; expands the IRF2BPL phenotypes in the Chinese population; and raises awareness of patients with IRF2BPL.

An IRF2BP member (CgIRF2BP) involved in negative regulation of CgIFNLP expression in oyster Crassostrea gigas.

The IRF2BP family of transcription regulators act as corepressor molecules by inhibiting both enhancer-activated and basal transcription involving in many biological contexts. In the present study, an IRF2BP homologue (CgIRF2BP) was identified from oyster C. gigas. Its open reading frame is of 1809 bp encoding a polypeptide of 602 amino acids, which contains an IRF-2BP1_2 domain and a RING domain. The mRNA transcripts of CgIRF2BP were detected in all tested tissues with highest level in haemocytes (28.99-fold of that in mantle, p < 0.05). After poly (I:C) stimulation, the expression level of CgIRF2BP was significantly down-regulated at 3 h (0.50-fold of that in control group, p < 0.001) and gradually increased from 6 h to 48 h (2.69-fold of that in control group, p < 0.01). The recombinant protein of CgIRF2BP (rCgIRF2BP) showed high affinity to both rCgIRF1 and rCgIRF8 with Kd value of 1.02 × 10-7 and 2.09 × 10-7, respectively. In CgIRF2BP-RNAi oysters, the mRNA expression of CgIFNLP, CgMx1, CgViperin and CgIFI44L were significantly increased after poly (I:C) stimulation, which were 2.88 (p < 0.01), 1.83 (p < 0.05), 2.47 (p < 0.05), and 1.99-fold (p < 0.01) of that in EGFP group, respectively. These findings suggested that CgIRF2BP negatively regulated CgIFNLP expression by binding with CgIRF1 and CgIRF8.

Hirudin ameliorates diabetic nephropathy by inhibiting Gsdmd-mediated pyroptosis.

Our group previously reported that hirudin ameliorated diabetic nephropathy (DN) in streptozotocin (STZ)-injected rats, but the mechanism remained largely unknown. Therefore, we further explored its possible mechanism. We subcutaneously injected 5 U hirudin into STZ-induced WT mice or Gasdermin D (Gsdmd)-/- (KO) mice daily for 12 weeks, respectively, and evaluated their kidney injury. Next, glomerular endothelial cells (GECs), renal tubular epithelial cells (RTECs), and bone-marrow-derived macrophages (BMDMs) were isolated from WT mice and treated with hirudin in the presence of high glucose/lipopolysaccharides and ATP to measure the release of interleukin-18 and interleukin-1ß. Kidney injury induced by STZ injection was significantly ameliorated by hirudin through inhibiting Gsdmd-mediated pyroptosis in the mice, not Caspase 1-mediated apoptosis. Meanwhile, hirudin also suppressed pyroptosis in primary GECs, RTECs, and BMDMs in vitro. Moreover, the deletion of Gsdmd reduced pyroptosis and kidney injury both in vivo and in vitro. We also found that hirudin regulated the expression of Gsdmd by inhibiting interferon regulatory factor 2 (Irf2). Hirudin ameliorated Gsdmd-mediated pyroptosis by inhibiting irf2, leading to the improvement of kidney injury. Therefore, hirudin might serve as a potential therapeutic strategy to treat DN.

IRF2BP2 is a novel HNF4α co-repressor: Its role in gluconeogenic gene regulation via biochemically labile interaction.

Hepatocyte nuclear factor 4α (HNF4α) has essential roles in controlling the expression of a variety of genes involved in key metabolic pathways, including gluconeogenesis in the liver. The mechanistic and physiological significance of peroxisome proliferator-activated receptor gamma co-activator-1α (PGC-1α) for HNF4α-mediated transcriptional activation models for gluconeogenic genes is well characterized. However, the transcriptional repression of HNF4α for those genes remains to be examined. In this study, we applied novel proteomic techniques to evaluate the interactions of HNF4α, including those with biochemically labile binding proteins. Based upon our experiments, we identified interferon regulatory factor 2 binding protein 2 (IRF2BP2) as a novel HNF4α co-repressor. This interaction could not be detected by conventional immunoprecipitation. IRF2BP2 repressed the transcriptional activity of HNF4α dependent on its E3 ubiquitin ligase activity. Deficiency of the IRF2BP2 gene in HepG2 cells induced gluconeogenic genes comparable to that of forskolin-treated wild-type HepG2 cells. Together, these results suggest that IRF2BP2 represents a novel class of nuclear receptor co-regulator.

IRF-2 inhibits cancer proliferation by promoting AMER-1 transcription in human gastric cancer.

BACKGROUND: Interferon regulatory factor 2 (IRF-2) acts as an anti-oncogene in gastric cancer (GC); however, the underlying mechanism remains unknown. METHODS: This study determined the expression of IRF-2 in GC tissues and adjacent non-tumor tissues using immunohistochemistry (IHC) and explored the predictive value of IRF-2 for the prognoses of GC patients. Cell function and xenograft tumor growth experiments in nude mice were performed to test tumor proliferation ability, both in vitro and in vivo. Chromatin immunoprecipitation sequencing (ChIP-Seq) assay was used to verify the direct target of IRF-2. RESULTS: We found that IRF-2 expression was downregulated in GC tissues and was negatively correlated with the prognoses of GC patients. IRF-2 negatively affected GC cell proliferation both in vitro and in vivo. ChIP-Seq assay showed that IRF-2 could directly activate AMER-1 transcription and regulate the Wnt/ß-catenin signaling pathway, which was validated using IHC, in both tissue microarray and xenografted tumor tissues, western blot analysis, and cell function experiments. CONCLUSIONS: Increased expression of IRF-2 can inhibit tumor growth and affect the prognoses of patients by directly regulating AMER-1 transcription in GC and inhibiting the Wnt/ß-catenin signaling pathway.

Analysis of miRNA Expression Profiling of RIP2 Knockdown in Chicken HD11 Cells When Infected with Avian Pathogenic E. coli (APEC).

Colibacillosis is an acute and chronic avian disease caused by avian pathogenic E. coli (APEC). Previous studies have demonstrated that RIP2 plays a significant role in APEC infection. Moreover, increasing evidence indicates that microRNAs (miRNAs) are involved in host-pathogen interactions and the immune response. However, the role of miRNAs in the host against APEC infection remains unclear. Herein, we attempted to reveal new miRNAs potentially involved in the regulation of the immune and inflammatory response against APEC infection, with a particular focus on those possibly correlated with RIP2 expression, via miRNA-seq, RT-qPCR, Western blotting, dual-luciferase reporter assay, and CCK-8. The results showed that a total of 93 and 148 differentially expressed (DE) miRNAs were identified in the knockdown of RIP2 cells following APEC infection (shRIP2+APEC) vs. knockdown of RIP2 cells (shRIP2) and shRIP2 vs. wild-type cells (WT), respectively. Among those identified DE miRNAs, the biological function of gga-miR-455-5p was investigated. It was found that gga-miR-455-5p regulated by RIP2 was involved in the immune and inflammatory response against APEC infection via targeting of IRF2 to modulate the expression of type I interferons. Additionally, RIP2 could directly regulate the production of the type I interferons. Altogether, these findings highlighted the crucial role of miRNAs, especially gga-miR-455-5p, in host defense against APEC infection.

Circular RNA hsa_circ_0000658 inhibits osteosarcoma cell proliferation and migration via the miR-1227/IRF2 axis.

Osteosarcoma (OS) is the most frequently occurring bone cancer. Circular RNAs (circRNAs) have been shown to exert pivotal impact in modulation of gene expression, but their roles in OS are still not fully understood. In this study, we analysed the role of circ-0000658 in OS. Thereafter, molecular techniques such as Western blot, qRT-PCR, RNA-binding protein immunoprecipitation and Dual-Luciferase reporter assays were implemented to investigate the role of circ-0000658/miR-1227/interferon regulatory factor-2 (IRF2) axis in OS. Eventually, the impact of circ-0000658 on tumour growth and metastasis was observed in a xenograft mouse model. The results of this study revealed that circ-0000658 exhibits low levels in OS tissues and cell lines. Moreover, circ-0000658 repression promoted cell cycle, proliferation, invasion and migration but inhibited the apoptosis of OS cells. Researches have previously shown that circ-0000658 contains a binding site for miR-1227 and thus can abundantly sponge miR-1227 to up-regulate the expression of its target gene IRF2. Moreover, both inhibition of miR-1227 and overexpression of IRF2 reversed cell proliferation and invasion, which was triggered by circ-0000658 repression. Conclusively, circ-0000658 modulates biological function of OS cells through the miR-1227/IRF2 axis. Therefore, circ-0000658 might act as a possible novel therapeutic target for the treatment of OS.