Interleukin-1 Receptor-associated Kinase 1 Protein Research Articles

The in silico interaction analysis of CARMIL1 protein-containing leucine-rich repeat (LRR) regions with interleukin-1 receptor-associated kinase 1 (IRAK1) protein and LLR peptide

Objectives: Capping protein Arp2/3 and myosin-I linker protein 1 (CARMIL1) encoded by the CARMIL, is a major, multidomain, membrane-linked protein regulating actin assembly; however, its function in inflammatory signaling is not fully elucidated. The leucine-rich repeat (LRR) region of CARMIL1 has been associated with interleukin (IL)-1 receptor-associated kinase (IRAK) in fibroblasts by many methods including tandem mass tag mass spectrometry, immunoprecipitation, and CRISPR-Cas9. This study, therefore, set out to assess the interaction of CARMIL1 with each IRAK1 protein and a novel LRR peptide. Methods: The molecular docking techniques were employed to compare the binding modes and affinities of the 3D structure of CARMIL1 each of LRR peptides and IRAK1 protein. 3D structure model of CARMIL1 protein and LRR peptide was predicted through Robetta tool considering the structures and function of these proteins. Results: As an overall conclusion of docking, the LRR peptide was observed to contact the residues in the LRR 1-2 of the human CARMIL1, whereas the IRAK1 protein was to interact with the residues in the LRR 1, 2, and 10 regions of the human CARMIL1. Conclusions: Our computational results suggest that LRRs in CARMIL1 are involved in the formation of protein-peptide binding interfaces with its structural conformation.

Discovery of Highly Potent and Selective IRAK1 Degraders to Probe Scaffolding Functions of IRAK1 in ABC DLBCL.

MyD88 gene mutation has been identified as one of the most prevalent driver mutations in the activated B-cell-like diffuse large B-cell lymphoma (ABC DLBCL). The published literature suggests that interleukin-1 receptor-associated kinase 1 (IRAK1) is an essential gene for ABC DLBCL harboring MyD88 mutation. Importantly, the scaffolding function of IRAK1, rather than its kinase activity, is required for tumor cell survival. Herein, we present our design, synthesis, and biological evaluation of a novel series of potent and selective IRAK1 degraders. One of the most potent compounds, Degrader-3 (JNJ-1013), effectively degraded cellular IRAK1 protein with a DC50 of 3 nM in HBL-1 cells. Furthermore, JNJ-1013 potently inhibited IRAK1 downstream signaling pathways and demonstrated strong anti-proliferative effects in ABC DLBCL cells with MyD88 mutation. This work suggests that IRAK1 degraders have the potential for treating cancers that are dependent on the IRAK1 scaffolding function.

Targeting Interleukin‐1 Receptor‐Associated Kinase 1 (IRAK1) In Ovarian Cancer

Ovarian cancer (OvCa) is the leading cause of gynecologic cancer-related deaths, due largely to late-stage diagnoses and the development of chemoresistant disease. Nearly 70% of affected women develop recurrent disease, characterized by resistance to standard chemotherapy despite initial response. Cancer stem cells (CSCs) are a subset of cells that have an innate ability to self-renew and enter a dormant state and have been further implicated in resistance to chemotherapy due to high expression of the ATP-binding Cassette (ABC) transporters. To understand the pathways that may be implicated in enhancing this stem-like phenotype, RNA sequencing was performed on cisplatin sensitive and isogenic cisplatin-resistant OvCa cell lines, as well as cells grown in 2- dimensional (2-D) or 3-dimensional (3-D) cultures. OvCa cells grown as spheroids, a 3-D growth model, are enriched with CSCs, and therefore represent a surrogate for stemness. Interestingly, the Toll-like (TLR) or interleukin-1 (IL-1) receptor pathways were highly enriched in resistant cancer cells and spheroid cultures. A critical factor in these signaling pathways is the interleukin receptor associated kinase 1 (IRAK1). IRAK1 is also highly expressed in chemoresistant OvCa and is responsible for activating numerous downstream pathways involved in tumor progression, such as NF-kB, P38/MAPK, and C-Jun. High expression of IRAK1 is associated with poor overall survival based on analysis of the Cancer Genome Atlas (TCGA) publicly available datasets. Due to the important role IRAK1 has in OvCa growth signaling and patient outcomes, IRAK1 represents an attractive target for CSC-targeted drug therapy. The present study is aimed at identifying small molecule inhibitors of IRAK1 by using in-silico molecular docking-based screening. FDA-approved compound libraries were screened using Autodock Vina software. Compounds were assessed for binding within the c-terminal kinase domain. The compounds are ranked-based on their binding energies (BE) and hydrogen bonding patterns. Our screen identified multiple compounds, one of which included mebendazole, an anthelminthic with a BE of -10.3 kCal/mol. This suggests potent interaction with the kinase domain of IRAK1. To confirm the binding in vitro, we performed cellular thermal shift stability assays (CETSA). We observed that mebendazole treatment protected IRAK1 protein from thermal denaturation, confirming the in silico docking data. Lastly, we performed hexosaminidase proliferation assays to assess the effectiveness of mebendazole on inhibiting cancer cell growth. Cisplatin sensitive OvCar3, A1847, A2780 OvCa and cisplatin resistant C30 OvCa cell lines were treated with increasing doses of mebendazole. The inhibitory concentration 50 (IC50) was determined to be approximately 300 nM at 72h for all cell lines. This suggests that mebendazole has potent anti-cancer activity that may be, in part, mediated through the inhibition of IRAK1.

Upregulation of long non-coding RNA SNHG16 promotes diabetes-related RMEC dysfunction via activating NF-κB and PI3K/AKT pathways

Diabetic retinopathy (DR) is a severe diabetes-induced eye disease, in which its pathological phenomena basically include abnormal proliferation, migration, and angiogenesis of microvascular endothelial cells in the retina. Long non-coding RNAs (lncRNAs) have been proven to be important regulators in various biological processes, but their participation in DR remains largely undiscovered. In the present study, we aimed to unveil the role of lncRNA small nucleolar RNA host gene 16 (SNHG16) in regulating the functions of human retinal microvascular endothelial cells (hRMECs) under a high-glucose (HG) condition. We found that SNHG16 expression was significantly upregulated in hRMECs treated with HG. Functionally, SNHG16 could facilitate hRMEC proliferation, migration, and angiogenesis. Moreover, SNHG16 was associated with nuclear factor κB (NF-κB) and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. Mechanistically, SNHG16 could promote hRMEC dysfunction by sequestering microRNA (miR)-146a-5p and miR-7-5p to act as a competing endogenous RNA (ceRNA) with interleukin-1 receptor-associated kinase 1 (IRAK1) and insulin receptor substrate 1 (IRS1). In conclusion, our results illustrated the potential role of SNHG16 in facilitating hRMEC dysfunction under HG treatment, providing a novel approach for DR therapy.

Abstract 1487: Dysregulation of Interleukin-1 receptor-associated kinase 1 promotes prostate cancer-associated chronic inflammation and aggressiveness

Abstract For decades, chronic inflammation has been linked with cancer development. However, the molecular mechanisms of this association with respect to prostate cancer (PCa) aggressiveness are poorly understood. While previous studies exploiting the contributions of upstream and downstream inflammation signaling proteins to this oncogenic alliance have been clinically unsuccessful, the goal of our study is to elucidate the role of the often-neglected midstream inflammation regulatory proteins, such as the Interleukin-1 receptor-associated kinase 1 (IRAK1). We propose that the dysregulation of IRAK1 protein will promote PCa-associated chronic inflammation and aggressiveness. To explore the importance of IRAK1 in PCa-associated chronic inflammation and aggressiveness, both bioinformatics and experimental approaches were employed. Cutting-edge computational meta-analysis was used to characterize and assess the molecular patterns of gene expression and alteration of IRAK1 in clinical datasets of PCa patients acquired from open resource databases. Inflammation-associated PCa models were established by pre-exposure of aggressive PC3-CRPC cells to low doses (10ng-10µg/ml) of TLR-2, -3, -4 and -7/8 agonists, such as zymosan, poly (I:C), LPS, and resiquimod, respectively, which led to the upregulation of IRAK1 prior to mechanistic studies. Chronic inflammation was confirmed by measuring changes in the levels of IL-6/IL-12 via ELISA. IRAK1 mRNA and protein upregulation were analyzed by RT-PCR and western blot or immunofluorescent staining. Next, we investigated the effects of IRAK1 dysregulation on the aggressiveness of PCa cells by downregulating IRAK1 expression in PC3 cells by either pharmacologic inhibition with thymoquinone (an IRAK1 inhibitor) or via RNAi. MTT and colony forming assays were performed to assess the effects on cell viability and survival. IRAK1 mRNA and protein levels in PC3 cells following treatment with thymoquinone or IRAK1 inhibitor were measured using RT-PCR, western blot or immunocytochemistry. Cell migration was assessed by wound healing assay. Acridine orange/propidium iodide fluorescent staining and flow cytometry were used to analyze the effect on cell cycle and apoptosis. Our computational analysis shows that IRAK1 is commonly upregulated at the mRNA and protein levels and genetically altered/mutated in clinical PCa samples. Downregulation of IRAK1 by thymoquinone or RNAi in PC3 cells result in a decrease in cell viability, cell migration, and proinflammatory cytokines as well as an increase in apoptotic cell death in a dose and time-dependent manner. Upregulation of IRAK1 prior to treatment with PI3K/AKT/mTOR pathway inhibitors abrogates the anticancer effects of these drugs. Our study establishes IRAK1 as a promising therapeutic target to treat PCa-associated chronic inflammation and aggressiveness. Citation Format: Saheed Oluwasina Oseni, Cynthia Nguyen, Mirjana Pavlovic, James Kumi-Diaka. Dysregulation of Interleukin-1 receptor-associated kinase 1 promotes prostate cancer-associated chronic inflammation and aggressiveness [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1487.

Effect of high fat diet on NF-кB microRNA146a negative feedback loop in ovalbumin-sensitized rats.

The present study aimed to investigate the role of microRNA-146a and its adapter proteins [interleukin-1 receptor-associated kinase 1 (IRAK1) and tumor necrosis factor (TNF) receptor-associated factor 6 (TRAF6)] in the pathogenesis of ovalbumin (OVA)-sensitized rats in association with the diet-induced obesity condition. Twenty male Wistar rats were divided into four groups: control with normal diet (ND), OVA-sensitized with normal diet (S + ND), high-fat diet (HFD), and OVA-sensitized with high-fat diet (S + HFD). All the animals were fed for 8 weeks with standard pelts or high-fat diet, and were then sensitized and challenged with OVA or saline for another 4 weeks. The tracheal responsiveness to methacholine, serum protein levels, and lipid profile levels was measured by the ELISA method. Moreover, the gene expression level of microRNA-146a (miR-146a) was measured in the lung tissue of the rats using the real-time PCR method. Maximum response to methacholin increased in the S + HFD group in compared with ND, S + ND, and HFD groups (P < 0.05 to P < 0.001). Moreover, in the S + HFD group the mRNA expression levels of miRNA-146a increased in the lung tissue (P < 0.001). In addition, the protein analysis results showed that IRAK1, TRAF6, NF-kB, and IL-1β protein levels were high in the S + HFD group compared to the ND and HFD groups; however, in compared with the S + ND group, only the IL-1β protein level was higher in the S + HFD group (P < 0.05). These results suggest that a defect in the NF-kB-miR-146a negative feedback loop may be involved in the pathogenesis of obesity associated with OVA-sensitized condition. © 2018 BioFactors, 45(1):75-84, 2019.

MiR-146a promotes cervical cancer cell viability via targeting IRAK1 and TRAF6.

Cervical cancer is the third most common type of cancer in women, and microRNAs play an important role in this type of cancer. The elevated expression of miR-146a is involved in the pathogenesis of cancers generally, but its role in cervical cancer has not been fully elucidated. In the present study, we assessed the expression of miR-146a in G>C polymorphisms and confirmed that the overexpression of miR-146a promoted cervical cancer cell viability. The recombinant expression plasmids pre-miR-146a-G or pre-miR-146a-C including single nucleotide polymorphisms (SNP) were successfully constructed. Pre-miR-146a-G or pre-miR-146a-C was transfected into cervical cancer cells or immortalized non-tumorigenic cells and the expression of miR-146a was evaluated by real-time PCR. The cell viability, cell-cycle analysis and apoptosis were assessed using Cell Counting Kit-8 assay (CCK-8), flow cytometry and cleaved caspase-3 protein expression, respectively. The expression of interleukin 1 receptor associated kinase 1 (IRAK1), TNF receptor-associated factor 6 (TRAF6) and cyclin D1 was assessed following the transfection with a miR-146a mimic or a negative control. The cell viability and the number of S-phase cells increased after transfection with miR-146a mimic or an IRAK1 or TRAF6 interference fragment. After transfection, IRAK1 and TRAF6 protein expression was downregulated and the expression of cyclin D1 was upregulated, however apoptosis and cleaved caspase-3 were not affected. Polymorphisms in miR-146a precursor may be linked to the expression of miR-146a and may be a potential target for cervical cancer therapy.

MicroRNA-146a-5p Mediates High Glucose-Induced Endothelial Inflammation via Targeting Interleukin-1 Receptor-Associated Kinase 1 Expression.

Background and Aims: Interleukin-1 receptor-associated kinase-1 (IRAK-1) is critical for mediating toll-like receptor and interleukin-1 receptor signaling. In this study, we have examined whether IRAK-1 expression is altered in high glucose (HG)-stimulated human aortic endothelial cells (HAECs), and whether microRNAs (miRs) target IRAK-1 to regulate HG-induced endothelial inflammation.Methods: HAECs were treated with HG for 24 and 48 h. Real-time PCR, Western blot, monocyte adhesion assay, bioinformatics analysis, TaqMan® arrays, microRNA mimic or inhibitor transfection, luciferase reporter assay and siRNA IRAK-1 transfection were performed. The aortic tissues from db/db type 2 diabetic mice were examined by immunohistochemistry staining.Results: HG time-dependently increased IRAK-1 mRNA and protein levels in HAECs, and was associated with increased VCAM-1/ICAM-1 gene expression and monocyte adhesion. Bioinformatic analysis, TaqMan® arrays, and real-time PCR were used to confirm that miR-146a-5p, miR-339-5p, and miR-874-3p were significantly downregulated in HG-stimulated HAECs, suggesting impaired feedback restraints on HG-induced endothelial inflammation via IRAK-1. However, only miR-146a-5p mimic transfection reduced the HG-induced upregulation of IRAK-1 expression, VCAM-1/ICAM-1 expression, and monocyte adhesion. Additionally, IRAK-1 depletion reduced HG-induced VCAM-1/ICAM-1 gene expression, and monocyte adhesion, indicating that HG-induced endothelial inflammation was mediated partially through IRAK-1. In vivo, intravenous injections of miR-146a-5p mimic prevented endothelial IRAK-1 and ICAM-1 expression in db/db mice.Conclusion: These results suggest that miR-146a-5p is involved in the regulation of HG-induced endothelial inflammation via modulation of IRAK-1; indicating that miR-146a-5p may be a novel target for the treatment of diabetic vascular complications.

MicroRNA-146a and its adapter proteins are affected by diabetes in rat's heart.

This study was conducted to explore whether microRNA-146a and its adapter proteins (TNF-α receptor-associated factor 6 (TRAF6) and interleukin-1 receptor-associated kinase 1 (IRAK1)) are affected by diabetes in the rat heart. Twelve male Sprague-Dawley rats were randomized into control and diabetic groups (n = 6). Streptozotocin-nicotinamide experimental model was used to induce type 2 diabetes. The gene expression of MicroRNA-146a, nuclear factor-κB (NF-κB), IRAK1 and TRAF6, as well as NF-κB activity, IRAK1 and TRAF6 protein levels were measured. Moreover, NF-κB activity was measured in response to miR-146a mimic transfection (20 nmol) in human umbilical vein endothelial cells (HUVECs) under hyperglycemic condition (25 mM D-glucose for 24 h). The expression of MicroRNA-146a was increased in the heart tissue, 2 months after diabetes induction and in HUVECs. Also, the mRNA and protein levels of NF-κB, IRAK1 and TRAF6 were increased in the heart of diabetic rats. Moreover, transfection of miR-146a mimic prevented from a significant increase of NF-κB activity in hyperglycemic HUVECs. Presumably, a defect in the regulation of IRAK1 and TRAF6 can weaken miR-146a regulatory effect and provides a situation for sustained activation of NF-κB and its targets to promote cardiac cells toward abnormalities (Fig. 3, Ref. 28).

Valproic Acid Downregulates NF-κB p50 Activity and IRAK-1 in a Progressive Thyroid Carcinoma Cell Line

Histone deacetylase inhibitor (HDACI) valproic acid (VPA) is a promising drug, currently in clinical phase 2, for the therapy of advanced/poorly differentiated thyroid cancer. The nuclear factor-κB (NF-κB) pathway is constitutively activated in most tumors, including thyroid carcinomas; this often contributes to aggressive tumor growth and therapeutic resistance. We hypothesized that VPA could be useful to decrease NF-κB activity in human thyroid cancer cells. To clarify this, we treated the highly progressive thyroid cancer cell line BHT-101 with VPA (1.0-3.0 mM) for 48 h. Real-time polymerase chain reaction (PCR) and Western blot were used to measure expression of NF-κB-regulatory genes and proteins. NF-κB p50 activity was measured using an ELISA-based colorimetric transcription factor assay kit. We found that VPA significantly and dose-dependently impaired NF-κB activity reducing DNA binding activity of NF-κB p50 subunit by 30% at 1 mM, 40% at 1.5 mM, and 70% at 3 mM. Expression of interleukin-1 receptor-associated kinase-1 (IRAK-1) protein, an upstream mediator of NF-κB activation, was reduced by ̴30% at 1 and 1.5 mM. Furthermore, 3 mM VPA treatment significantly decreased expressions of IRAK-1, phospho-IκBα and NF-κB p50 subunit protein by ̴ 50%. This is the first study to demonstrate that VPA decreases NF-κB activity in a progressive thyroid cancer cell line. Intriguingly, 1mM of VPA, a clinically safe dose in the therapeutic range for epilepsy, was sufficient to reduce NF-κB activity. Thus, VPA may be a promising agent to overcome chemoresistance in cancer therapy and to improve therapeutic efficiency.

Abstract LB-469: An Epstein-Barr virus-encoded microRNA miR-BART5 upregulates human cellular microRNA miR-146a and downregulates IRAK1/NFκB in stomach cancer cells

Abstract Epstein-Barr virus (EBV) contributes to the development of the specific subsets of stomach cancer, nasopharyngeal cancer and malignant lymphoma etc. MicroRNAs (miRNAs) have been implicated in the regulation of various pathobiological processes in cancer. Recently, EBV-encoded viral miRNAs have been disclosed, whereas the functions of which remain largely unknown. A notable example of this is the human miRNA, which is targeted by viral miRNA. In this study, we investigated EBV-encoded viral miRNA miR-BART5/human cellular target interaction. The EBV miR-BART5 in EBV-infected stomach cancer cell line SNU719 was highly expressed comparing with that in EBV-infected lymphoma cell lines, Raji and Jijoye. In addition, EBV-infected stomach cancer cell revealed high level of human cellular miR-146a comparing with EBV-negative stomach cancer cells SNU601 and SNU216. Either miR-BART5 inhibitor product (anti-miR-BART5) or miR-BART5 precursor product (pre-miR-BART5) was transfected into EBV-infected stomach cancer cell, or EBV-negative stomach cancer cell, respectively. As a result, the expression of human cellular miR-146a was decreased in EBV-infected stomach cancer cell transfected with anti-miR-BART5 comparing with that in its original cell, while miR-146a was increased in EBV-negative stomach cancer cell transfected with pre-miR-BART5. As a predicted target of miR-146a, based on predicted base pairing using miRBase online program, we focused on interleukin-1 receptor-associated kinase 1 (IRAK1). Once EBV-negative stomach cancer cell was transfected with pre-miR-BART5, IRAK1 protein level was reduced by 50%, and nuclear factor-kappaB (NF-κB) (p65) was decreased. To check miR-BART5 influences on cellular biologic properties, when pre-miR-BARF5 was transfected into EBV-negative stomach cancer cell, invasion capacity of cancer cell was suppressed with a statistical significance. In conclusion, miR-BART5 could inhibit invasion of stomach cancer cell, which is in part due to the upregulation of miR-146a and downregulation of IRAK-1/ NF-κB signal pathway, offering clinicopathologic entity with a better prognosis to EBV-infected stomach cancer. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-469. doi:1538-7445.AM2012-LB-469

MiR-146a Mediates Protective Innate Immune Tolerance in the Neonate Intestine

After birth, the intestinal mucosa undergoesa dramatic transition from a sterile protected site to an environmentally exposed and permanently colonized surface. The mechanisms that facilitate this transition are ill defined. Here, we demonstrate that microRNA-146a-mediated translational repression and proteolytic degradation of the essential Toll-like receptor (TLR) signaling molecule interleukin 1 receptor associated kinase 1 (IRAK1) is sufficient to induce intestinal epithelial innate immune tolerance and provide protection from bacteria-induced epithelial damage in neonates. Despite low IRAK1 protein levels, continuous TLR4- and IRAK1-dependent signal transduction induced by intraepithelial endotoxin persistence during the neonatal period maintains tolerance through sustained miR-146a expression. Strikingly, it additionally facilitates transcription of a distinct set of genes involved in cell survival, differentiation, and homeostasis. Thus, our results identify the underlying molecular mechanisms of intestinal epithelial innate immune tolerance during the neonatal period and characterize tolerance as an active condition involved in the establishment of intestinal mucosal homeostasis.

The influence of over expression of interleukin-1 receptor-associated kinase 1 on bacterial lipoprotein-induced tolerance

To investigate Toll-like receptor 2 (TLR2) and interleukin-1 receptor-associated kinase 1 (IRAK-1) in bacterial lipoprotein (BLP) tolerance. Western blotting was used to confirm the over expression of TLR2 and IRAK-1 in human embryo kidney 293 (HEK293) cells. Plasmids for dual luciferase reporter gene with nuclear factor-KappaB promoter (pNF-KappaB-Luc) or CMV promoter (phRL-CMV internal control vector) were used to detect the NF-KappaB activation and the induction of BLP tolerance in HEK-TLR2 cells. BLP stimulation resulted in dose-dependent NF-KappaB activation in HEK293 cells stably expressing TLR2. And BLP pretreatment could reduce NF-KappaB activation and induce BLP tolerance in HEK-TLR2 cells. The NF-KappaB activation was 0.329+/-0.010 and 0.168+/-0.010 in BLP-activated and BLP-tolerant HEK-TLR2 cells, respectively. After transfection with 0.02 microg IRAK-1 plasmid, NF-KappaB activation in the two groups was 0.493+/-0.010 and 0.427+/-0.035, respectively (both P<0.01). So over expression of IRAK-1 could increase NF-KappaB activation in a dose-dependent manner. These results demonstrated that over expression of IRAK-1 could reverse BLP tolerance, whereas over expression of TLR2 failed to prevent the induction of BLP tolerance. Therefore reduced IRAK-1 protein expression is an important mechanism in the development of BLP-induced tolerance, suggesting that it could be a potentially important target for future therapeutic strategies in bacterial infection and sepsis.

Smad6 negatively regulates interleukin 1-receptor–Toll-like receptor signaling through direct interaction with the adaptor Pellino-1

Transforming growth factor-beta1 (TGF-beta1) is a potent cytokine with pleiotropic effects, including anti-inflammatory activity. Here we show that the signaling protein Smad6 bound to Pellino-1, an adaptor protein of mammalian interleukin 1 receptor (IL-1R)-associated kinase 1 (IRAK1), and thereby promoted TGF-beta-mediated anti-inflammatory effects. Smad6-Pellino-1 interaction abrogated signaling mediated by a complex of IRAK1, Pellino-1 and adaptor protein TRAF6 that formed after stimulation by IL-1beta treatment. Blockade of IRAK1-Pellino-1-TRAF6 signaling prevented degradation of the inhibitor IkappaBalpha and subsequent nuclear translocation of transcription factor NF-kappaB and thus expression of proinflammatory genes. 'Knockdown' of endogenous Smad6 expression by RNA interference reduced anti-inflammatory activity mediated by TGF-beta1 or the TGF-beta family member BMP-4. Thus Smad6 is a critical mediator of the TGF-beta-BMP pathway that mediates anti-inflammatory activity and negatively regulates IL-1R-Toll-like receptor signals.

Antisense IRAK-1 oligonucleotide blocks activation of NF-κB and AP-1 induced by IL-18

Interleukin-18 (IL-18) is a novel proinflammatory cytokine. Most of the immune and inflammatory genes induced by IL-18 are nuclear factor-kappaB (NF-κB)- and activator protein-1 (AP-1)-regulated. Interleukin-1 receptor-associated kinase-1 (IRAK-1) has recently been shown to be involved in IL-18-stimulated activation of NF-κB and AP-1. The purpose of this study is to investigate the effects of preventing IRAK-1 expression by antisense IRAK-1 oligodeoxynucleotide (ODN) on IL-18-stimulated activation of NF-κB and AP-1. Semiquantitative reverse transcription-PCR (RT-PCR) and western blot analysis revealed that antisense IRAK-1 ODN inhibited IRAK-1 mRNA and protein expression (P<0.01). As a result, antisense IRAK-1 ODN attenuated IL-18-induced activation of NF-κB and AP-1 as measured by sandwich ELISA in a concentration (1–8 μg ml−1)- and time (5–24 h)-dependent fashion. These data suggest that antisense IRAK-1 ODN may share a role in the design of antiinflammatory therapeutics.