IRAK family in inflammatory autoimmune diseases

miR-148-1-5p modulates NF-κB signaling pathway by targeting IRAK1 in miiuy croaker (Miichthys miiuy)

microRNAs (miRNAs), a crucial class of small non-coding RNA species, have been extensively studied as key molecular in immune regulation in the past decades. Here, we discover a new miRNA miR-148-1-5p and we elaborate that miR-148-1-5p functions as a negative regulator to participate in innate immune responses. In this article, it has been researched that the regulation effect of miR-148-1-5p to the nuclear factor kappaB (NF-κB) signaling pathway by targeting IRAK1 in miiuy croaker. First, through bioinformatics software to predict the potential targets of miR-148-1-5p, we found that IRAK1 had a base complementary region with indicated miRNA. Next, the dual-luciferase assays revealed that overexpression of miR-148-1-5p mimics and pre-miR-148 plasmid could significantly inhibit the luciferase activity of wild-type IRAK1-3'UTR. However, miR-148-1-5p inhibitors attenuated the inhibition caused by miR-148-1-5p. In addition, we also confirmed that miR-148-1-5p could suppress the expression of IRAK1 at mRNA level. Collectively, the regulations of miR-148-1-5p to NF-κB signaling pathways via targeting the IRAK1 gene was studied in miiuy croaker, which provided new information to enrich the immune regulation network of miRNA in teleost fish.

Hsa_circ_0010957 knockdown attenuates lipopolysaccharide-induced HK2 cell injury by regulating the miR-1224-5p/IRAK1 axis

Circular RNAs (circRNAs) are involved in the progression of various diseases, including lupus nephritis. Hsa_circ_0010957 is reported to be dysregulated in lupus nephritis, but the exact function of this circRNA is unknown. This research aims to study the function and mechanism of circRNA hsa_circ_0010957 in a lipopolysaccharide (LPS)-induced cellular model of lupus nephritis. Human renal proximal tubular cell line HK2 cells were challenged by LPS. Hsa_circ_0010957, microRNA-1224-5p (miR-1224-5p), and interleukin-1 receptor-associated kinase 1 (IRAK1) abundances were examined by quantitative reverse transcription polymerase chain reaction or western blot. LPS-induced damage was evaluated via cell viability, apoptosis, inflammatory response and oxidative injury. The target interaction was analyzed by dual-luciferase reporter analysis and RNA immunoprecipitation. Hsa_circ_0010957 abundance was enhanced in LPS-challenged HK2 cells. Hsa_circ_0010957 knockdown alleviated LPS-induced apoptosis, the inflammatory response and oxidative injury in HK2 cells. MiR-1224-5p was targeted by hsa_circ_0010957, and miR-1224-5p knockdown reversed the influence of hsa_circ_0010957 silence on LPS-induced injury. IRAK1 was targeted via miR-1224-5p, and hsa_circ_0010957 could regulate IRAK1 by miR-1224-5p. MiR-1224-5p overexpression could mitigate LPS-induced apoptosis, the inflammatory response and oxidative injury, and this effect was abolished by IRAK1. Hsa_circ_0010957 silence weakened LPS-induced HK2 cell apoptosis, the inflammatory response and oxidative injury via regulating the miR-1224-5p/IRAK1 axis.

Activation loop phosphorylaton of a non-RD receptor kinase initiates plant innate immune signaling

Receptor kinases (RKs) are fundamental for extracellular sensing and regulate development and stress responses across kingdoms. In plants, leucine-rich repeat receptor kinases (LRR-RKs) are primarily peptide receptors that regulate responses to myriad internal and external stimuli. Phosphorylation of LRR-RK cytoplasmic domains is among the earliest responses following ligand perception, and reciprocal transphosphorylation between a receptor and its coreceptor is thought to activate the receptor complex. Originally proposed based on characterization of the brassinosteroid receptor, the prevalence of complex activation via reciprocal transphosphorylation across the plant RK family has not been tested. Using the LRR-RK ELONGATION FACTOR TU RECEPTOR (EFR) as a model, we set out to understand the steps critical for activating RK complexes. While the EFR cytoplasmic domain is an active protein kinase in vitro and is phosphorylated in a ligand-dependent manner in vivo, catalytically deficient EFR variants are functional in antibacterial immunity. These results reveal a noncatalytic role for EFR in triggering immune signaling and indicate that reciprocal transphoshorylation is not a ubiquitous requirement for LRR-RK complex activation. Rather, our analysis of EFR along with a detailed survey of the literature suggests a distinction between LRR-RKs with RD- versus non-RD protein kinase domains. Based on newly identified phosphorylation sites that regulate the activation state of the EFR complex in vivo, we propose that LRR-RK complexes containing a non-RD protein kinase may be regulated by phosphorylation-dependent conformational changes of the ligand-binding receptor, which could initiate signaling either allosterically or through driving the dissociation of negative regulators of the complex.

Associations of IRAK1 Gene Polymorphisms and mRNA Expression With NMOSD Risk in the Northern Chinese Han Population

Objectives: Interleukin (IL)-1 receptor-associated kinase 1 (IRAK1) is a very important immunomodulatory gene for autoimmune diseases located on the X chromosome. However, there was little study about the correlation of IRAK1 functional single nucleotide polymorphisms with mRNA expression in neuromyelitis optica spectrum disorder (NMOSD) patients. In this study, we aimed to investigate the plausible association of IRAK1 polymorphism, IRAK1 mRNA expression, and NMOSD risk in the northern Chinese Han population. Methods: Four loci of IRAK1 gene (rs1059702, rs7061789, rs1059703, and rs3027898) were genotyped using multiplex SNaPshot technique in 102 NMOSD patients and 213 healthy subjects. Allele, genotype, and haplotype frequencies were compared. Stratified analyses were conducted by age, sex, AQP4 status, and age of onset. IRAK1 mRNA levels in the peripheral blood mononuclear cells of 30 NMOSD patients (of active phase) and 15 healthy control subjects were detected using qPCR. The correlations between the SNP polymorphisms and mRNA expression levels of genes were tested using non-parametric tests. Results: The minor allele frequencies (MAF) of these four locis were significantly lower in NMOSD cases than that of the controls. The frequencies of rs1059703G/G genotype, rs1059702A/A genotype, rs3027898 C/C genotype, and rs7061789G/G genotype were higher in the case group than that of the control group. Haplotype analysis revealed that the major haplotype "G-A-C-G" (alleles in the order of SNPs rs1059703, rs1059702, rs3027898, and rs7061789), containing the risk alleles, conferred an adverse effect on NMOSD. The level of IRAK1mRNA was markedly higher in NMOSD when compared to the healthy control groups. The IRAK1mRNA levels of female patients with the major haplotype were significantly higher compared to those with other haplotypes and to the male patients with the same genotype. Conclusion: IRAK1 polymorphisms were highly correlated with NMOSD susceptibility. Its haplotype G-A-C-G (rs1059703-rs1059702-rs3027898-rs7061789) confers increasing the risk of NMOSD in female patients. The IRAK1 risk haplotype G-A-C-G upregulated IRAK1 mRNA expression in female NMOSD patients. Our study provides a novel insight into the molecular mechanism of the pathogenesis of NMOSD and reveals that IRAK1 is the potential mechanism-specific druggable target in NMOSD disease.

Blocking of Birc3/TLR4/Myd88 signaling protects carbapenem-resistant klebsiella pneumoniae in a mouse model of infection

BACKGROUND

Klebsiella pneumonia (KP) and carbapenem-resistant Klebsiella pneumonia (CRKP) lung infections significantly increase the morbidity and mortality of pneumonia. Recent studies have shown that baculoviral IAP repeat-containing 3 (Birc3) plays an important role in the prevention and treatment of pneumonia. However, the role of Birc3 in CRKP-induced pneumonia has not been widely reported.

METHODS

In vivo, we successfully established a mouse model of pneumonia induced by KP and CRKP. In vitro, we established a macrophage model treated with KP and CRKP. The phagocytosis of macrophages treated with CRKP was measured by Flow cytometry and coated plate counting. STRING and Co-IP assays were used to predict and verify the relationship between Birc3 and toll-like receptor 4 (TLR4) or myeloid differentiation factor 88 (Myd88). HE staining was used to detect the lung pathological changes of anti-Birc3 IgG inhibited CRKP-induced inflammatory cells. The levels of inflammatory factors and proteins were detected by ELISA and Western blot, respectively.

RESULTS

The phagocytic ability of macrophages was reduced, and the cytokine storm was enhanced in CRKP treated Raw264.7 cells. Macrophages treated with CRKP impaired phagocytosis. Birc3 could interact with TLR4 and MyD88. Anti-Birc3 IgG inhibited CRKP-induced inflammatory cell lung infiltration. In addition, mice treated with anti-Birc3 IgG improved the CRKP-induced inflammatory cell lung infiltration, bacterial spread, and cytokine storm by inhibiting the Birc3/TLR4/Myd88 signaling pathway.

CONCLUSION

The results suggest that Birc3 may serve as a target for the treatment of bacterial infection and lung inflammation in CRKP-induced pneumonia.

PROTACs technology for targeting non-oncoproteins: Advances and perspectives

Proteolysis targeting chimeras (PROTACs) have been developed to be an effective technology for targeted protein degradation. Each PROTAC contains three key components: a protein-of-interest (POI) ligand, an E3 ligase ligand, and a linker. These bifunctional molecules can hijack the intracellular inherent ubiquitin-proteasome system to degrade different POIs. With several advantages over other therapeutic strategies, PROTACs have set off a new upsurge of drug discovery in recent years. PRTOACs have been extensively explored worldwide and have excelled not only in cancer diseases but also in cardiovascular diseases, fatty liver disease, immune diseases, neurodegenerative diseases, and viral infections. In this review, we aim to summarize the rapid progress from 2010 to 2021 in PROTACs targeting various non-oncoproteins and elucidate the advantages of PROTACs technology. Finally, the potential challenges of this dynamic field are also discussed.

Sinner or Saint?: Nck Adaptor Proteins in Vascular Biology

The Nck family of modular adaptor proteins, including Nck1 and Nck2, link phosphotyrosine signaling to changes in cytoskeletal dynamics and gene expression that critically modulate cellular phenotype. The Nck SH2 domain interacts with phosphotyrosine at dynamic signaling hubs, such as activated growth factor receptors and sites of cell adhesion. The Nck SH3 domains interact with signaling effectors containing proline-rich regions that mediate their activation by upstream kinases. In vascular biology, Nck1 and Nck2 play redundant roles in vascular development and postnatal angiogenesis. However, recent studies suggest that Nck1 and Nck2 differentially regulate cell phenotype in the adult vasculature. Domain-specific interactions likely mediate these isoform-selective effects, and these isolated domains may serve as therapeutic targets to limit specific protein-protein interactions. In this review, we highlight the function of the Nck adaptor proteins, the known differences in domain-selective interactions, and discuss the role of individual Nck isoforms in vascular remodeling and function.

Interleukin-1 receptor-associated kinase-4 gene variation may increase post-bronchiolitis asthma risk

AIM

Evidence based on studies of the encoding genes suggests that interleukin-1 receptor-associated kinase-4 (IRAK4) plays a role in childhood asthma and allergy. Our aim was to evaluate the associations of six IRAK4 gene polymorphisms with presence of asthma and allergic rhinitis and use of inhaled corticosteroids (ICSs) for asthma at 5-7 and 11-13 years of ages after hospitalisation for bronchiolitis at younger than 6 months of age.

METHODS

IRAK4 rs4251513, rs4251520, rs4251522, rs4251578, rs79154645 and rs13852554 polymorphisms were determined in 141 former bronchiolitis patients prospectively followed up until 5-7 and in 125 children until 11-13 years of age.

RESULTS

The homozygous variant IRAK4 rs4251513 genotype was associated with the presence of asthma and allergic rhinitis and use of ICSs at 5-7 and 11-13 years of ages in univariate analyses. Statistical significance remained for the presence of asthma and use of ICSs but was lost in the case of allergic rhinitis in multivariate analyses. The adjusted odds ratios were 3.48 and 4.16 for asthma and 5.22 and 14.00 for ICS use at these two ages.

CONCLUSION

The homozygous variant IRAK4 rs4251513 genotype was constantly associated with post-bronchiolitis asthma and asthma medication in school-aged children.

Small molecule approaches to treat autoimmune and inflammatory diseases (Part I): Kinase inhibitors

Autoimmune and inflammatory diseases place a huge burden on the healthcare system. Small molecule (SM) therapeutics provide much needed complementary treatment options for these diseases. This digest series highlights the latest progress in the discovery and development of safe and efficacious SMs to treat autoimmune and inflammatory diseases with each part representing a class of SMs, namely: 1) protein kinases; 2) nucleic acid-sensing pathways; and 3) soluble ligands and receptors on cell surfaces. In this first part of the series, the focus is on kinase inhibitors that emerged between 2018 and 2020, and which exhibit increased target and tissue selectivity with the aim of increasing their therapeutic index.

DNA methylation-mediated silencing of microRNA-204 enhances T cell acute lymphoblastic leukemia by up-regulating MMP-2 and MMP-9 via NF-κB

T cell acute lymphoblastic leukaemia (T‐ALL) is a highly aggressive haematological cancer of the bone marrow. The abnormal expression of microRNAs (miRNAs) is reportedly involved in T‐ALL development and progression. Thus, we aimed to decipher the involvement of miR‐204 silencing mediated by DNA methylation in the occurrence of T cell acute lymphoblastic leukaemia (T‐ALL). miR‐204 expression was determined in bone marrow and peripheral blood samples from T‐ALL patients by real‐time quantitative PCR (RT‐qPCR) with its effect on cell proliferation evaluated by functional assays. In addition, bisulphite sequencing PCR was employed to detect the DNA methylation level of the miR‐204 promoter region, and the binding site between miR‐204 and IRAK1 was detected by luciferase assay. We found that miR‐204 was down‐regulated in T cells of T‐ALL patients, which was caused by the increased DNA methylation in the promoter region of miR‐204. Moreover, overexpression of miR‐204 inhibited T‐ALL cell proliferation while enhancing their apoptosis through interleukin receptor‐associated kinase 1 (IRAK1), which enhanced the expression of matrix metalloproteinase‐2 (MMP‐2) and MMP‐9 through activation of p‐p65. Thus, miR‐204 modulated MMP‐2 and MMP‐9 through IRAK1/NF‐κB signalling pathway, which was confirmed by in vivo assay. Taken together, DNA methylation‐mediated miR‐204 silencing increased the transcription of IRAK1, thus activating the NF‐κB signalling pathway and up‐regulating the downstream targets MMP‐2/MMP‐9.

Trichlorocarban induces developmental and immune toxicity to zebrafish (Danio rerio) by targeting TLR4/MyD88/NF-κB signaling pathway

Trichlorocarban (TCC) is ubiquitously detected in environmental matrices, while there is a paucity of information regarding its systemic toxicity. In the present study, we observed that TCC exposure led to high embryo mortality, delayed hatching and yolk absorption, as well as increased malformations, such as closure of swim sac and yolk sac edema. Meanwhile, TCC affected the formation and branch of subintestinal veins (SIVs), intersegmental vessels and posterior cardinal veins. Especially, the SIVs were shrunk, and their branches were reduced or even broken along with reduced coverage area. TCC-induced oxidative stress and excessive apoptosis resulted from abnormal expression of the anti/pro-apoptotic genes. Significant reduction in the number and aggregation function of immune cells proved that TCC had prominent immunotoxicity to zebrafish. TCC-targeted TLR4 signaling pathway was demonstrated by abnormal expression of the marker genes (tlr4, MyD88 and nf-κb) and release of the downstream inflammatory factors (TNF-α, IL-6, etc.). Inhibition of TLR4/MyD88/NF-κB pathway by an inhibitor (CA-4948) rescued the decreasing trend of the immune cells induced by TCC. Molecular docking results demonstrated that TCC could stably bind to TLR4 receptor to form hydrogen bonds and hydrophobic interactions with amino acids. Overall, these findings reveal the underlying molecular mechanisms on TCC-induced developmental and immune toxicity to zebrafish.

Downregulation of IRAK1 Prevents the Malignant Behavior of Hepatocellular Carcinoma Cells by Blocking Activation of the MAPKs/NLRP3/IL-1β Pathway

INTRODUCTION

Interleukin-1 receptor-associated kinase 1 (IRAK1) was shown to contribute to a variety of cancer-related processes. However, the function of IRAK1 in hepatocellular carcinoma (HCC) pathogenesis has not been investigated in detail.

METHODS

IRAK1 expression in HCC was examined by immunohistochemistry, qRT-PCR, and Western blot assays. In addition, Huh7 and Hep3B cells were transfected with IRAK1 siRNAs and/or a NOD-like receptor family pyrindomain containing 3 (NLRP3) plasmid. Western blot, EdU staining, and Transwell assays were performed to determine changes of apoptosis, proliferation, migration, and invasion in HCC cells. Moreover, changes in the expression of proteins involved in the MAPKs/NLRP3/IL-1β pathway were confirmed by Western blotting.

RESULTS

IRAK1 was found to be highly upregulated in HCC tissues and cells. Knockdown of IRAK1 signaling prevented the proliferation, invasion, migration, epithelial-mesenchymal transition (EMT) of HCC cells. Mechanistically, we found that activation of the MAPKs/NLRP3/IL-1β pathway could be markedly suppressed by IRAK1 knockdown in HCC cells. Furthermore, our data showed that NLRP3 could partially reverse the reduced aggressive biological behaviors of HCC cells which were caused by RAK1 knockdown.

CONCLUSION

Knockdown of IRAK1 prevented HCC progression by inhibiting the ability of NLRP3 to block the MAPKs/IL-1β pathway, suggesting that approach as a strategy for treating HCC.

Silencing TLR4/MyD88/NF-κB Signaling Pathway Alleviated Inflammation of Corneal Epithelial Cells Infected by ISE

The regulatory role of toll-like receptor 4 (TLR4) in the inactivate staphylococcus epidermidis (ISE)-induced cornea inflammation is not well investigated. Here, TLR4 silence could decrease inflammatory cytokines in corneal epithelial cells treated with ISE. The mouse corneal epithelial cells were exposed to ISE for 24 h, either alone or with the NF-κB inhibitor, TLR4 lentivirus to bilaterally (knock-down or and overexpression). The expression of TLR4 in mouse corneal epithelial cells was investigated using western blot and qRT-PCR assay. The inflammatory cytokine levels were evaluated by qRT-PCR and ELISA, respectively. The relative impact factors of TLR4-mediated NF-κB signaling detected using western blot assay. Results show the expression levels of TLR4 and some inflammatory cytokines were significantly increased in corneal epithelial cells treated with ISE. TLR4 Silence markedly decreased ISE-induced production of IL12, TNF-α, CCL5, and CCL9 in corneal epithelial cells. Furthermore, the nuclear translocation of NF-κB p65 and myeloid differentiation protein 88 (MyD88) in the cells treated with ISE were further reduced by silencing TLR4. Inhibition of TLR4-mediated NF-κB signaling by using BAY11-7082 also alleviated ISE-induced inflammation. In the rescue experiment, transfected the stable TLR4 silenced corneal epithelial cells with TLR4 overexpression lentivirus, we found that TLR4 overexpression can restore the down-regulation of TLR4 and inflammatory cytokines (IL12, TNF-α, CCL9) caused by TLR4 knocked down. Therefore, ISE-induced cornea inflammation was due to the activation of the TLR4/MyD88/NF-κB signaling pathway, and dramatically stimulated IL12, TNF-α, CCL9 secretion. TLR4 silence presented mitigates damage in corneal epithelial cells treated with ISE.

Discovery of Proteolysis-Targeting Chimera Molecules that Selectively Degrade the IRAK3 Pseudokinase

We report the first disclosure of IRAK3 degraders in the scientific literature. Taking advantage of an opportune byproduct obtained during our efforts to identify IRAK4 inhibitors, we identified ready-to-use, selective IRAK3 ligands in our compound collection with the required properties for conversion into proteolysis-targeting chimera (PROTAC) degraders. This work culminated with the discovery of PROTAC 23, which we demonstrated to be a potent and selective degrader of IRAK3 after 16 h in THP1 cells. 23 induced proteasome-dependent degradation of IRAK3 and required both CRBN and IRAK3 binding for activity. We conclude that PROTAC 23 constitutes an excellent in vitro tool with which to interrogate the biology of IRAK3.

A Genetic Screen for Human Genes Suppressing FUS Induced Toxicity in Yeast

FUS is a nucleic acid binding protein that, when mutated, cause a subset of familial amyotrophic lateral sclerosis (ALS). Expression of FUS in yeast recapitulates several pathological features of the disease-causing mutant proteins, including nuclear to cytoplasmic translocation, formation of cytoplasmic inclusions, and cytotoxicity. Genetic screens using the yeast model of FUS have identified yeast genes and their corresponding human homologs suppressing FUS induced toxicity in yeast, neurons and animal models. To expand the search for human suppressor genes of FUS induced toxicity, we carried out a genome-scale genetic screen using a newly constructed library containing 13570 human genes cloned in an inducible yeast-expression vector. Through multiple rounds of verification, we found 37 human genes that, when overexpressed, suppress FUS induced toxicity in yeast. Human genes with DNA or RNA binding functions are overrepresented among the identified suppressor genes, supporting that perturbations of RNA metabolism is a key underlying mechanism of FUS toxicity.

MicroRNA (miRNA): A New Dimension in the Pathogenesis of Antiphospholipid Syndrome (APS)

MicroRNAs (miRNAs) are single-stranded, endogenous RNA molecules that play a significant role in the regulation of gene expression as well as cell development, differentiation, and function. Recent data suggest that these small molecules are responsible for the regulation of immune responses. Therefore, they may act as potent modulators of the immune system and play an important role in the development of several autoimmune diseases. Antiphospholipid syndrome (APS) is an autoimmune systemic disease characterized by venous and/or arterial thromboses and/or recurrent fetal losses in the presence of antiphospholipid antibodies (aPLs). Several lines of evidence suggest that like other autoimmune disorders, miRNAs are deeply involved in the pathogenesis of APS, interacting with the function of innate and adaptive immune responses. In this review, we characterize miRNAs in the light of having a functional role in the immune system and autoimmune responses focusing on APS. In addition, we also discuss miRNAs as potential biomarkers and target molecules in treating APS.