Role Of Interferon Regulatory Factor Research Articles

IRF4 Suppresses Osteogenic Differentiation of Periodontal Ligament Stem Cells by Activating IL-18 Signaling Pathway in Periodontitis.

The present study aims to investigate the role of interferon regulatory factor 4 (IRF4) in osteogenic differentiation of periodontal ligament stem cells (PDLSCs) and analyze the underlying signaling of these processes. In this study, IRF4 is upregulated in periodontitis periodontal ligament tissues, as compared to healthy periodontal ligament tissues. IRF4 knockdown increases cell proliferation, decreases levels of tumor necrosis factor-alpha, interleukin-6, and interleukin-8, enhances osteogenic activity, and increases the expression of RUNX family transcription factor 2, Collagen I, and Osteocalcin in PDLSCs. The opposite results are observed in IRF4 overexpressed PDLSCs. Additionally, GSEA shows that IRF4 activates the interleukin-18 (IL-18) signaling pathway. The expressions of IL-18, B-cell translocation gene 2, interleukin-1beta, and caspase-3 are decreased by IRF4 knockdown, while increased by IRF4 overexpression. IL-18 overexpression eliminates the promoting effect of IRF4 knockdown on osteogenic differentiation of PDLSCs. In conclusion, IRF4 suppresses osteogenic differentiation of PDLSCs by activating the IL-18 signaling pathway.

IRF5 suppresses metastasis through the regulation of tumor-derived extracellular vesicles and pre-metastatic niche formation

Metastasis is driven by extensive cooperation between a tumor and its microenvironment, resulting in the adaptation of molecular mechanisms that evade the immune system and enable pre-metastatic niche (PMN) formation. Little is known of the tumor-intrinsic factors that regulate these mechanisms. Here we show that expression of the transcription factor interferon regulatory factor 5 (IRF5) in osteosarcoma (OS) and breast carcinoma (BC) clinically correlates with prolonged survival and decreased secretion of tumor-derived extracellular vesicles (t-dEVs). Conversely, loss of intra-tumoral IRF5 establishes a PMN that supports metastasis. Mechanistically, IRF5-positive tumor cells retain IRF5 transcripts within t-dEVs that contribute to altered composition, secretion, and trafficking of t-dEVs to sites of metastasis. Upon whole-body pre-conditioning with t-dEVs from IRF5-high or -low OS and BC cells, we found increased lung metastatic colonization that replicated findings from orthotopically implanted cancer cells. Collectively, our findings uncover a new role for IRF5 in cancer metastasis through its regulation of t-dEV programming of the PMN.

The Role of Interferon Regulatory Factors in Liver Diseases.

The interferon regulatory factors (IRFs) family comprises 11 members that are involved in various biological processes such as antiviral defense, cell proliferation regulation, differentiation, and apoptosis. Recent studies have highlighted the roles of IRF1-9 in a range of liver diseases, including hepatic ischemia-reperfusion injury (IRI), alcohol-induced liver injury, Con A-induced liver injury, nonalcoholic fatty liver disease (NAFLD), cirrhosis, and hepatocellular carcinoma (HCC). IRF1 is involved in the progression of hepatic IRI through signaling pathways such as PIAS1/NFATc1/HDAC1/IRF1/p38 MAPK and IRF1/JNK. The regulation of downstream IL-12, IL-15, p21, p38, HMGB1, JNK, Beclin1, β-catenin, caspase 3, caspase 8, IFN-γ, IFN-β and other genes are involved in the progression of hepatic IRI, and in the development of HCC through the regulation of PD-L1, IL-6, IL-8, CXCL1, CXCL10, and CXCR3. In addition, IRF3-PPP2R1B and IRF4-FSTL1-DIP2A/CD14 pathways are involved in the development of NAFLD. Other members of the IRF family also play moderately important functions in different liver diseases. Therefore, given the significance of IRFs in liver diseases and the lack of a comprehensive compilation of their molecular mechanisms in different liver diseases, this review is dedicated to exploring the molecular mechanisms of IRFs in various liver diseases.

DNA Damage and Cellular Senescence in Osteoarthritis: An Unexpected Role for Interferon Regulatory Factor 1 in Chondrocyte DNA Repair.

DNA Damage and Cellular Senescence in Osteoarthritis: An Unexpected Role for Interferon Regulatory Factor 1 in Chondrocyte DNA Repair.

Roles of Interferon Regulatory Factor 1 in Tumor Progression and Regression: Two Sides of a Coin.

IRF1 is a transcription factor well known for its role in IFN signaling. Although IRF1 was initially identified for its involvement in inflammatory processes, there is now evidence that it provides a function in carcinogenesis as well. IRF1 has been shown to affect several important antitumor mechanisms, such as induction of apoptosis, cell cycle arrest, remodeling of tumor immune microenvironment, suppression of telomerase activity, suppression of angiogenesis and others. Nevertheless, the opposite effects of IRF1 on tumor growth have also been demonstrated. In particular, the "immune checkpoint" molecule PD-L1, which is responsible for tumor immune evasion, has IRF1 as a major transcriptional regulator. These and several other properties of IRF1, including its proposed association with response and resistance to immunotherapy and several chemotherapeutic drugs, make it a promising object for further research. Numerous mechanisms of IRF1 regulation in cancer have been identified, including genetic, epigenetic, transcriptional, post-transcriptional, and post-translational mechanisms, although their significance for tumor progression remains to be explored. This review will focus on the established tumor-suppressive and tumor-promoting functions of IRF1, as well as the molecular mechanisms of IRF1 regulation identified in various cancers.

Abstract 13582: Interferon Regulatory Factor 8 Promotes Abdominal Aortic Aneurysm via Inducing Type I Conventional Dendritic Cell Differentiation

Introduction: Abdominal aortic aneurysm (AAA) remains to be the most common true aneurysm worldwide. Previous studies identified the participation of dendritic cells (DC) in the pathogenesis of AAA. However, the detailed subtypes involved and mechanisms remain unknown. Our previous RNA-Seq data determined dramatically increased Irf8 in AAA samples, which drives DC differentiating to Type I conventional dendritic cells (cDC1). Aim: The aim of the work is to determine the role of interferon regulatory factor 8 (IRF8) in the development of AAA. Methods and Results: Murine AAA were induced via elastase infusion. The single-cell transcriptomic sequencing of CD45+ cells in murine AAA samples identified the dramatically increased cDC1. By flow cytometry, we found that the ratio of CD103 + cDC1s reached maximum at day 7. Compared with the control group, Irf8 CAG-LSL Itgax Cre mice ( Irf8 overexpression in DC) suffered significantly more severe aneurysm expansion, elastin degradation and apoptosis of smooth muscle cells, while the AAA development in Irf8 flox/flox Itgax Cre mice ( Irf8 deletion in DC) was less sharp. Batf3 -/- mice which were cDC1 depleted, showed similar characteristic in AAA expansion with Irf8 flox/flox Itgax Cre mice. The effective CD8 + T cells increased significantly in Irf8 CAG-LSL Itgax Cre mice than the control group, while decreased in Irf8 flox/flox Itgax Cre ones. Deletion of Clec9a which blocks cross-present dead-cell-associated antigens to the CD8 + T cells, also attenuated AAA development, in accordance with Irf8 flox/flox Itgax Cre mice in gross anatomy and pathology changes. Conclusion: Our findings suggest that the activation of IRF8 promotes cDC1 differentiation, which subsequently activate CD8 + T cells and contribute to destruction of the aortic-wall and AAA formation.

IRF1 regulates self-renewal and stress responsiveness to support hematopoietic stem cell maintenance.

Hematopoietic stem cells (HSCs) are tightly controlled to maintain a balance between blood cell production and self-renewal. While inflammation-related signaling is a critical regulator of HSC activity, the underlying mechanisms and the precise functions of specific factors under steady-state and stress conditions remain incompletely understood. We investigated the role of interferon regulatory factor 1 (IRF1), a transcription factor that is affected by multiple inflammatory stimuli, in HSC regulation. Our findings demonstrate that the loss of IRF1 from mouse HSCs significantly impairs self-renewal, increases stress-induced proliferation, and confers resistance to apoptosis. In addition, given the frequent abnormal expression of IRF1 in leukemia, we explored the potential of IRF1 expression level as a stratification marker for human acute myeloid leukemia. We show that IRF1-based stratification identifies distinct cancer-related signatures in patient subgroups. These findings establish IRF1 as a pivotal HSC controller and provide previously unknown insights into HSC regulation, with potential implications to IRF1 functions in the context of leukemia.

Astrocytes evoke a robust IRF7-independent type I interferon response upon neurotropic viral infection

BackgroundType I interferons (IFN-I) are fundamental in controlling viral infections but fatal interferonopathy is restricted in the immune-privileged central nervous system (CNS). In contrast to the well-established role of Interferon Regulatory Factor 7 (IRF7) in the regulation of IFN-I response in the periphery, little is known about the specific function in the CNS.MethodsTo investigate the role for IRF7 in antiviral response during neurotropic virus infection, mice deficient for IRF3 and IRF7 were infected systemically with Langat virus (LGTV). Viral burden and IFN-I response was analyzed in the periphery and the CNS by focus formation assay, RT-PCR, immunohistochemistry and in vivo imaging. Microglia and infiltration of CNS-infiltration of immune cells were characterized by flow cytometry.ResultsHere, we demonstrate that during infection with the neurotropic Langat virus (LGTV), an attenuated member of the tick-borne encephalitis virus (TBEV) subgroup, neurons do not rely on IRF7 for cell-intrinsic antiviral resistance and IFN-I induction. An increased viral replication in IRF7-deficient mice suggests an indirect antiviral mechanism. Astrocytes rely on IRF7 to establish a cell-autonomous antiviral response. Notably, the loss of IRF7 particularly in astrocytes resulted in a high IFN-I production. Sustained production of IFN-I in astrocytes is independent of an IRF7-mediated positive feedback loop.ConclusionIFN-I induction in the CNS is profoundly regulated in a cell type-specific fashion.

Targeting the mechanism of IRF3 in sepsis-associated acute kidney injury via the Hippo pathway

Sepsis-induced inflammatory damage and adaptive repair are critical in the pathophysiological mechanisms of acute kidney injury (AKI). Here, we investigated the role of interferon regulatory factor three (IRF3) and subsequent activation of the Hippo pathway in inflammatory damage and repair using an in vitro cell model of LPS-induced AKI. LPS caused the phosphorylation and activation of IRF3 in the early stages of sepsis, and activated IRF3 enhanced the production of type I interferon (IFN), resulting in an excessive inflammatory response. Furthermore, LPS generated considerably more inflammatory injury than intended cell death, and IRF3 activation triggered the Hippo pathway, causing a reduction in YAP, which eventually impaired proliferation and repair in surviving renal tubular epithelial cells and exacerbated the development of AKI. In conclusion, IRF3 promoted the development of sepsis-associated AKI (SAKI) by modulating the Hippo pathway.

Interferon regulatory factor 7 in inflammation, cancer and infection.

Interferon regulatory factor 7 (IRF7), a member of the interferon regulatory factors (IRFs) family, is located downstream of the pattern recognition receptors (PRRs)-mediated signaling pathway and is essential for the production of type I interferon (IFN-I). Activation of IRF7 inhibits various viral and bacterial infections and suppresses the growth and metastasis of some cancers, but it may also affect the tumor microenvironment and promote the development of other cancers. Here, we summarize recent advances in the role of IRF7 as a multifunctional transcription factor in inflammation, cancer and infection by regulating IFN-I production or IFN-I-independent signaling pathways.

IRF3 in adipose tissue inflammation and metabolism

Abstract Dysfunction of adipocytes and adipose tissue is a primary defect in obesity and obesity-associated metabolic diseases. Interferon regulatory factor 3 (IRF3) has been implicated in adipogenesis. However, the role of IRF3 in obesity and obesity associated disorders still remains unclear. Here we show that IRF3 expression in human adipose tissue was positively associated with insulin sensitivity and negatively associated with type 2 diabetes. In mouse preadipocytes, IRF3 not only acts as a brake negatively regulating the adipogenic transcriptional network centered on the PPARg pathway, but also is important for the functionality of adipocytes. In macrophages, IRF3 inhibits inflammatory cytokine expression through IFNb/IL-10 axis, thereby restraining adipose tissue inflammation in obesity. Mice deficient in IRF3 developed obesity and type 2 diabetes spontaneously associated with increased adipose tissue inflammation. This study demonstrates that IRF3 regulates the biology of multiple cell types including adipocytes and macrophages to prevent the development of obesity and obesity-related complications, hence, could be a target for therapeutic interventions for prevention and treatment of obesity-associated metabolic disorders. National Medical Research Council of Singapore

Abstract P5-15-01: Rediscovering IRF5: A prognostic indicator with novel roles in mammary gland development, ribosome biogenesis, tumor initiation, and metastasis

Abstract Breast cancer is the second leading cause of death for women in the United States. However, only 10% of breast cancers have been linked to inherited genomic mutations. Thus, identifying biomarkers to predict cancer progression and metastasis remains a clear need in the research and medical world. Here, we report a novel role for Interferon Regulatory Factor 5 (IRF5) in mammary gland development, tumorigenesis, and metastasis. Historically, IRF5 has been studied as a transcription factor in the context of genetic risk for autoimmune diseases. However, mining of The Cancer Genome Atlas revealed that loss of IRF5 expression in human breast cancer is significantly linked with progression to high grade carcinoma, increased metastasis, and decreased overall and recurrence-free survival. Supporting these analyses, we demonstrated that female Irf5-/- BALB/c mice have higher incidence of spontaneous atypical ductal hyperplasia (ADH), increased progression to DCIS, and ultimately, increased incidence of IDC. Using qPCR, FISH and IHC, we confirmed that IRF5 is expressed in both luminal and basal myoepithelial cells, but expression is higher in basal cells. Histologic analysis of whole mount preparations of Irf5-/- mammary glands revealed aberrant ductal morphogenesis, characterized by expansion of luminal and basal myoepithelial cells with a loss of organized glandular structure. RNAseq of primary mammary epithelial cells from wild type and Irf5-/- littermate mice showed Irf5-/- mammary epithelial cells to be enriched in ribosome biogenesis pathways, the physiologic consequences of which were demonstrated through increased rates of protein synthesis. Transferring our studies in vivo, we demonstrated that loss of tumor IRF5 expression resulted in decreased tumor-infiltrating lymphocytes and increased pulmonary metastasis in the murine orthotopic 4T1 implantation model. Mechanistically, we found that—as in our studies utilizing primary mammary epithelial cells—IRF5 expression in tumors regulated protein translation and ribosome biogenesis. In light of these findings, we propose IRF5 as a novel prognostic biomarker, loss of which alters mammary gland development, drives tumor initiation and metastasis, and dysregulates mammary epithelial cell protein synthesis. Citation Format: Betsy Barnes, Zarina Brune, Matthew Rice, Carter Somerville. Rediscovering IRF5: A prognostic indicator with novel roles in mammary gland development, ribosome biogenesis, tumor initiation, and metastasis [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P5-15-01.

IRF1 promotes the chondrogenesis of human adipose-derived stem cells through regulating HILPDA

BackgroundOsteoarthritis is a main cause of deformity in aging people. The chondrogenesis of human adipose-derived stem cells (hADSCs) has a positive effect on the cure of osteoarthritis. However, the regulatory mechanism of hADSC chondrogenesis still needs further exploration. This research investigates the role of interferon regulatory factor 1 (IRF1) in the chondrogenesis of hADSCs. MethodshADSCs were purchased and cultured. The interaction between IRF1 and hypoxia inducible lipid droplet associated (HILPDA) was predicted by bioinformatics analysis, and verified through dual-luciferase reporter and chromatin immunoprecipitation assays. The expressions of IRF1 and HILPDA in osteoarthritis cartilage samples were measured through qRT-PCR. After hADSCs were transfected or further induced for chondrogenesis, the chondrogenesis was visualized by Alcian blue staining, and the expressions of IRF1, HILPDA and chondrogenesis-related factors (SOX9, Aggrecan, COL2A1, MMP13, MMP3) were determined through qRT-PCR or Western blot. ResultsHILPDA bound to IRF1 in hADSCs. IRF1 and HILPDA levels were up-regulated during the chondrogenesis of hADSCs. Overexpressions of IRF1 and HILPDA promoted the chondrogenesis of hADSCs with the up-regulation of SOX9, Aggrecan and COL2A1 and the down-regulation of MMP13 and MMP3; however, IRF1 silencing generated the opposite effects. Besides, HILPDA overexpression reversed the effects of IRF1 silencing on inhibiting chondrogenesis of hADSCs and regulating the expressions of chondrogenesis-related factors. ConclusionIRF1 promotes the chondrogenesis of hADSCs through up-regulating HILPDA level, providing novel biomarkers for treating osteoarthritis.

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.

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.

IRF5 knockdown reverses TDP-related phenotypes partially by increasing TBK1 expression

Interferon-regulatory factor 5 (IRF5) participates in the regulation of apoptosis, affects the phenotype of inflammatory macrophages and plays an essential role in the inflammatory response. However, the role of IRF5 in the progression of amyotrophic lateral sclerosis (ALS) remains largely unknown. Here, we show that IRF5 mainly accumulated in the nucleus in cells expressing the truncated 25 kD C-terminal fragments of TDP-43 (TDP-25, named TDP-25 cells hereafter). IRF5 knockdown using a lentivirus carrying an shRNA in TDP-25 cells exerted a protective effect and reduced the level of the apoptosis-related protein cleaved caspase-9 and the cell cycle arrest protein p21, while increasing the expression of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) and its target molecule glutamate-cysteine ligase modulatory subunit (GCLM). Furthermore, IRF5-knockdown cells showed improved mitochondrial swelling and cristae dilation. In addition, we found that IRF5 mediated neuronal injury partly through the negative regulation of TANK-binding kinase 1 (TBK1). These data indicate that the loss of IRF5 in TDP-25 cells exerts a protective effect mainly by inhibiting apoptosis, regulating cell cycle arrest and alleviating oxidative stress.

IRF8 regulates efficacy of therapeutic anti-CD20 monoclonal antibodies.

Anti-CD20 monoclonal antibodies such as Rituximab, Ofatumumab, and Obinutuzumab are widely used to treat lymphomas and autoimmune diseases. They act by depleting B cells, mainly through Fc-dependent effectors functions. Some patients develop resistance to treatment but the underlying mechanisms are poorly understood. Here, we performed a genome-wide CRISPR/Cas9 screen to identify genes regulating the efficacy of anti-CD20 antibodies. We used as a model the killing of RAJI B cells by Rituximab through complement-dependent-cytotoxicity (CDC). As expected, the screen identified MS4A1, encoding CD20, the target of Rituximab. Among other identified genes, the role of Interferon Regulatory Factor 8 (IRF8) was validated in two B-cell lines. IRF8 KO also decreased the efficacy of antibody-dependent cellular cytotoxicity and phagocytosis (ADCC and ADCP) induced by anti-CD20 antibodies. We further show that IRF8 is necessary for efficient CD20 transcription. Levels of IRF8 and CD20 RNA or proteins correlated in normal B cells and in hundreds of malignant B cells. Therefore, IRF8 regulates CD20 expression and controls the depleting capacity of anti-CD20 antibodies. Our results bring novel insights into the pathways underlying resistance to CD20-targeting immunotherapies.

IRF2BP2 attenuates gestational diabetes mellitus by activating AMPK signaling

Purpose: To investigate the role of interferon regulatory factor 2 binding protein 2 (IRF2BP2) in gestational diabetes mellitus (GDM).
 Methods: Mice were injected intraperitoneally with streptozotocin to establish a model of GDM and then subjected to intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT) to determine glucose and insulin tolerances. Lipid metabolism was evaluated by enzyme-linked immunosorbent assay (ELISA). The histomorphology of pancreatic islets was assessed by hematoxylin and eosin staining.
 Results: IRF2BP2 was downregulated in pancreatic tissues of mice with GDM (p < 0.001). Mice in GDM group showed higher blood glucose levels than those in normal pregnancy group. However, overexpression of IRF2BP2 reduced glucose and insulin levels in mice with GDM. Overexpression of IRF2BP2 increased the level of high-density lipoprotein (HDL) and reduced triglyceride (TG), total cholesterol (TC), and low-density lipoprotein (LDL) levels in mice with GDM (p < 0.001). The histopathological changes in the islets of mice with GDM were also ameliorated by overexpression of IRF2BP2. Overexpression of IRF2BP2 reduced IL-6, IL-1β, and TNF-α levels and increased protein expression of p-AMPK in mice with GDM.
 Conclusion: IRF2BP2 ameliorates the outcomes of GDM and suppressed inflammation in mice with GDM through activation of AMPK signaling. Thus, IRF2BP2 is a potential therapeutic strategy for the management of GDM.
 Keywords: IRF2BP2; inflammation; gestational diabetes mellitus; AMPK; mice; insulin tolerance

The Role of Interferon Regulatory Factors in Non-Alcoholic Fatty Liver Disease and Non-Alcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is becoming the most common chronic liver disease with many metabolic comorbidities, such as obesity, diabetes, and cardiovascular diseases. Non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, accompanies the progression of hepatic steatosis, inflammation, cell death, and varying degree of liver fibrosis. Interferons (IFNs) have been shown to play important roles in the pathogenesis of NAFLD and NASH. Their regulating transcriptional factors such as interferon regulatory factors (IRFs) can regulate IFN expression, as well as genes involved in macrophage polarization, which are implicated in the pathogenesis of NAFLD and advanced liver disease. In this review, the roles of IRF-involved signaling pathways in hepatic inflammation, insulin resistance, and immune cell activation are reviewed. IRFs such as IRF1 and IRF4 are also involved in the polarization of macrophages that contribute to critical roles in NAFLD or NASH pathogenesis. In addition, IRFs have been shown to be regulated by treatments including microRNAs, PPAR modulators, anti-inflammatory agents, and TLR agonists or antagonists. Modulating IRF-mediated factors through these treatments in chronic liver disease can ameliorate the progression of NAFLD to NASH. Furthermore, adenoviruses and CRISPR activation plasmids can also be applied to regulate IRF-mediated effects in chronic liver disease. Pre-clinical and clinical trials for evaluating IRF regulators in NAFLD treatment are essential in the future direction.

The Modulation of Interferon Regulatory Factor-1 via Caspase-1-Mediated Alveolar Macrophage Pyroptosis in Ventilator-Induced Lung Injury.

Background To examine the role of interferon regulatory factor-1 (IRF-1) and to explore the potential molecular mechanism in ventilator-induced lung injury. Methods Wild-type C57BL/6 mice and IRF-1 gene knockout mice/caspase-1 knockout mice were mechanically ventilated with a high tidal volume to establish a ventilator-related lung injury model. The supernatant of the alveolar lavage solution and the lung tissues of these mice were collected. The degree of lung injury was examined by hematoxylin and eosin staining. The protein and mRNA expression levels of IRF-1, caspase-1 (p10), and interleukin (IL)-1β (p17) in lung tissues were measured by western blot and quantitative real-time polymerase chain reaction, respectively. Pyroptosis of alveolar macrophages was detected by flow cytometry and western blotting for active caspase-1 and cleaved GSDMD. An enzyme-linked immunosorbent assay was used to measure the levels of IL-1β, IL-18, IL-6, TNF-α, and high mobility group box protein 1 (HMGB-1) in alveolar lavage fluid. Results IRF-1 expression and caspase-1-dependent pyroptosis in lung tissues of wild-type mice were significantly upregulated after mechanical ventilation with a high tidal volume. The degree of ventilator-related lung injury in IRF-1 gene knockout mice and caspase-1 knockout mice was significantly improved compared to that in wild-type mice, and the levels of GSDMD, IL-1β, IL-18, IL-6, and HMGB-1 in alveolar lavage solution were significantly reduced (P < 0.05). The expression levels of caspase-1 (p10), cleaved GSDMD, and IL-1β (p17) proteins in lung tissues of IRF-1 knockout mice with ventilator-related lung injury were significantly lower than those of wild-type mice, and the level of pyroptosis of macrophages in alveolar lavage solution was significantly reduced. Conclusions IRF-1 may aggravate ventilator-induced lung injury by regulating the activation of caspase-1 and the focal death of alveolar macrophages.