Ligandability Assessment of IL-1ß by Integrated Hit Identification Approaches.

Human interleukin-1ß (IL-1ß) is a pro-inflammatory cytokine that plays a critical role in the regulation of the immune response and the development of various inflammatory diseases. In this publication, we disclose our efforts toward the discovery of IL-1ß binders that interfere with IL-1ß signaling. To this end, several technologies were used in parallel, including fragment-based screening (FBS), DNA-encoded library (DEL) technology, peptide discovery platform (PDP), and virtual screening. The utilization of distinct technologies resulted in the identification of new chemical entities exploiting three different sites on IL-1ß, all of them also inhibiting the interaction with the IL-1R1 receptor. Moreover, we identified lysine 103 of IL-1ß as a target residue suitable for the development of covalent, low-molecular-weight IL-1ß antagonists.

Myeloid Cell-Derived IL-1 Signaling Damps Neuregulin-1 from Fibroblasts to Suppress Colitis-Induced Early Repair of the Intestinal Epithelium.

Neuregulin-1 (Nrg1, gene symbol: Nrg1), a ligand of the ErbB receptor family, promotes intestinal epithelial cell proliferation and repair. However, the dynamics and accurate derivation of Nrg1 expression during colitis remain unclear. By analyzing the public single-cell RNA-sequencing datasets and employing a dextran sulfate sodium (DSS)-induced colitis model, we investigated the cell source of Nrg1 expression and its potential regulator in the process of epithelial healing. Nrg1 was majorly expressed in stem-like fibroblasts arising early in mouse colon after DSS administration, and Nrg1-Erbb3 signaling was identified as a potential mediator of interaction between stem-like fibroblasts and colonic epithelial cells. During the ongoing colitis phase, a significant infiltration of macrophages and neutrophils secreting IL-1ß emerged, accompanied by the rise in stem-like fibroblasts that co-expressed Nrg1 and IL-1 receptor 1. By stimulating intestinal or lung fibroblasts with IL-1ß in the context of inflammation, we observed a downregulation of Nrg1 expression. Patients with inflammatory bowel disease also exhibited an increase in NRG1+IL1R1+ fibroblasts and an interaction of NRG1-ERBB between IL1R1+ fibroblasts and colonic epithelial cells. This study reveals a novel potential mechanism for mucosal healing after inflammation-induced epithelial injury, in which inflammatory myeloid cell-derived IL-1ß suppresses the early regeneration of intestinal tissue by interfering with the secretion of reparative neuregulin-1 by stem-like fibroblasts.

IL-1 receptor 1 signaling shapes the development of viral antigen-specific CD4+ T cell responses following COVID-19 mRNA vaccination.

BACKGROUND: The innate immune cytokine interleukin (IL)-1 can affect T cell immunity, a critical factor in host defense. In a previous study, we identified a subset of human CD4+ T cells which express IL-1 receptor 1 (IL-1R1). However, the expression of such receptor by viral antigen-specific CD4+ T cells and its biological implication remain largely unexplored. This led us to investigate the implication of IL-1R1 in the development of viral antigen-specific CD4+ T cell responses in humans, including healthy individuals and patients with primary antibody deficiency (PAD), and animals. METHODS: We characterized CD4+ T cells specific for SARS-CoV-2 spike (S) protein, influenza virus, and cytomegalovirus utilizing multiplexed single cell RNA-seq, mass cytometry and flow cytometry followed by an animal study. FINDINGS: In healthy individuals, CD4+ T cells specific for viral antigens, including S protein, highly expressed IL-1R1. IL-1ß promoted interferon (IFN)-γ expression by S protein-stimulated CD4+ T cells, supporting the functional implication of IL-1R1. Following the 2nd dose of COVID-19 mRNA vaccines, S protein-specific CD4+ T cells with high levels of IL-1R1 increased, likely reflecting repetitive antigenic stimulation. The expression levels of IL-1R1 by such cells correlated with the development of serum anti-S protein IgG antibody. A similar finding of increased expression of IL-1R1 by S protein-specific CD4+ T cells was also observed in patients with PAD following COVID-19 mRNA vaccination although the expression levels of IL-1R1 by such cells did not correlate with the levels of serum anti-S protein IgG antibody. In mice immunized with COVID-19 mRNA vaccine, neutralizing IL-1R1 decreased IFN-γ expression by S protein-specific CD4+ T cells and the development of anti-S protein IgG antibody. INTERPRETATION: Our results demonstrate the significance of IL-1R1 expression in CD4+ T cells for the development of viral antigen-specific CD4+ T cell responses, contributing to humoral immunity. This provides an insight into the regulation of adaptive immune responses to viruses via the IL-1 and IL-1R1 interface. FUNDING: Moderna to HJP, National Institutes of Health (NIH) 1R01AG056728 and R01AG055362 to IK and KL2 TR001862 to JJS, Quest Diagnostics to IK and RB, and the Mathers Foundation to RB.

IL-1R1 signaling in TBI: assessing chronic impacts and neuroinflammatory dynamics in a mouse model of mild closed-head injury.

Neuroinflammation contributes to secondary injury cascades following traumatic brain injury (TBI), with alternating waves of inflammation and resolution. Interleukin-1 (IL-1), a critical neuroinflammatory mediator originating from brain endothelial cells, microglia, astrocytes, and peripheral immune cells, is acutely overexpressed after TBI, propagating secondary injury and tissue damage. IL-1 affects blood-brain barrier permeability, immune cell activation, and neural plasticity. Despite the complexity of cytokine signaling post-TBI, we hypothesize that IL-1 signaling specifically regulates neuroinflammatory response components. Using a closed-head injury (CHI) TBI model, we investigated IL-1's role in the neuroinflammatory cascade with a new global knock-out (gKO) mouse model of the IL-1 receptor (IL-1R1), which efficiently eliminates all IL-1 signaling. We found that IL-1R1 gKO attenuated behavioral impairments 14 weeks post-injury and reduced reactive microglia and astrocyte staining in the neocortex, corpus callosum, and hippocampus. We then examined whether IL-1R1 loss altered acute neuroinflammatory dynamics, measuring gene expression changes in the neocortex at 3, 9, 24, and 72 h post-CHI using the NanoString Neuroinflammatory panel. Of 757 analyzed genes, IL-1R1 signaling showed temporal specificity in neuroinflammatory gene regulation, with major effects at 9 h post-CHI. IL-1R1 signaling specifically affected astrocyte-related genes, selectively upregulating chemokines like Ccl2, Ccl3, and Ccl4, while having limited impact on cytokine regulation, such as Tnfα. This study provides further insight into IL-1R1 function in amplifying the neuroinflammatory cascade following CHI in mice and demonstrates that suppression of IL-1R1 signaling offers long-term protective effects on brain health.

A paracrine circuit of IL-1ß/IL-1R1 between myeloid and tumor cells drives genotype-dependent glioblastoma progression.

Monocytes and monocyte-derived macrophages (MDMs) from blood circulation infiltrate glioblastoma (GBM) and promote growth. Here, we show that PDGFB-driven GBM cells induce the expression of the potent proinflammatory cytokine IL-1ß in MDM, which engages IL-1R1 in tumor cells, activates the NF-κB pathway, and subsequently leads to induction of monocyte chemoattractant proteins (MCPs). Thus, a feedforward paracrine circuit of IL-1ß/IL-1R1 between tumors and MDM creates an interdependence driving PDGFB-driven GBM progression. Genetic loss or locally antagonizing IL-1ß/IL-1R1 leads to reduced MDM infiltration, diminished tumor growth, and reduced exhausted CD8+ T cells and thereby extends the survival of tumor-bearing mice. In contrast to IL-1ß, IL-1α exhibits antitumor effects. Genetic deletion of Il1a/b is associated with decreased recruitment of lymphoid cells and loss-of-interferon signaling in various immune populations and subsets of malignant cells and is associated with decreased survival time of PDGFB-driven tumor-bearing mice. In contrast to PDGFB-driven GBM, Nf1-silenced tumors have a constitutively active NF-κB pathway, which drives the expression of MCPs to recruit monocytes into tumors. These results indicate local antagonism of IL-1ß could be considered as an effective therapy specifically for proneural GBM.

The expression profiling and clinical significance of a chronic pain-related gene IL1R1.

Chronic pain is a disease that existed during cancer treatment for a long time. It has been reported that interleukin (IL)-1 is involved in the inflammatory response during tumor development. IL1R1 and IL1R2 are members of the IL-1 receptor family of cytokine receptors. However, few studies have reported the role of chronic pain-related genes, IL1R1, in pan-cancer. In this study, 8 lumbar disc prolapse (LDP) patients and 8 controls with differentially expressed genes were investigated to find chronic pain-related genes. Then, IL1R1 was analyzed using the TCGA database. The clinical survival data from TCGA were used to analyze the prognostic value of IL1R1. This study further evaluated the relationship between IL1R1 and immune checkpoints, immune-activating genes, immunosuppressive genes, chemokines, and chemokine receptors. IL1R1 was expressed in varying degrees in most TCGA tumor types, indicating a better survival status. The expression of IL1R1 is closely related to T cell infiltration, immune checkpoints, immune-activating genes, immunosuppressive genes, chemokines, and chemokine receptors. The results show that IL1R1 is a kind of potential cancer biomarker. Coordination with other immune checkpoints IL1R1k may adjust the immune microenvironment, immunotherapy can be applied to the development of new targeted drugs.

Interleukin-1 contributes to clonal expansion and progression of bone marrow fibrosis in JAK2V617F-induced myeloproliferative neoplasm.

Chronic inflammation is frequently associated with myeloproliferative neoplasms (MPN), but the role of inflammation in the pathogenesis of MPN remains unclear. Expression of the proinflammatory cytokine interleukin-1 (IL-1) is elevated in patients with MPN as well as in Jak2V617F knock-in mice. Here, we show that genetic deletion of IL-1 receptor 1 (IL-1R1) normalizes peripheral blood counts, reduces splenomegaly and ameliorates bone marrow fibrosis in homozygous Jak2V617F mouse model of myelofibrosis. Deletion of IL-1R1 also significantly reduces Jak2V617F mutant hematopoietic stem/progenitor cells. Exogenous administration of IL-1ß enhances myeloid cell expansion and accelerates the development of bone marrow fibrosis in heterozygous Jak2V617F mice. Furthermore, treatment with anti-IL-1R1 antibodies significantly reduces leukocytosis and splenomegaly, and ameliorates bone marrow fibrosis in homozygous Jak2V617F mice. Collectively, these results suggest that IL-1 signaling plays a pathogenic role in MPN disease progression, and targeting of IL-1R1 could be a useful strategy for the treatment of myelofibrosis.

IL-1R1 blockade attenuates liver injury through inhibiting the recruitment of myeloid-derived suppressor cells in sepsis.

Myeloid-derived suppressor cells (MDSCs) mobilize and migrate from bone marrow to peripheral tissues or immune organs, which is associated with poor prognosis in sepsis. Intervention of MDSCs might be a potential target for the effective treatment of sepsis. In the present study, we demonstrated that IL-1R1 blockade with either recombinant human IL-1R antagonist Anakinra or IL-1R1 deficiency had a protective effect on the liver injury in septic mice. The possible mechanism was that Anakinra treatment and IL-1R1 knockout inhibited the migration of MDSCs to the liver in sepsis, thus attenuating the immune suppression of MDSCs on effector T cells characterized with the decrease in proportion of CD4+ and CD8+ T cells. Furthermore, the switch from pro-inflammatory M1 macrophage to anti-inflammatory M2 phenotype and the ability of bacterial clearance in the liver of septic mice were enhanced obviously by Anakinra and IL-1R1 deficiency, which contributes to the attenuated liver injury. Taken together, these findings provide new ideas for revealing the relationship between IL-1R1 and MDSCs in sepsis, thereby providing a potentially effective target for ameliorating septic liver injury.

Why are the phenotypes of TRAF6 knock-in and TRAF6 knock-out mice so different?

The expression of TNF-Receptor Associated Factor 6 (TRAF6) is essential for many physiological processes. Here we studied the phenotype of TRAF6[L74H] knock-in mice which are devoid of TRAF6 E3 ligase activity in every cell of the body, but express normal levels of the TRAF6 protein. Remarkably, TRAF6[L74H] mice have none of the phenotypes seen in TRAF6 KO mice. Instead TRAF6[L74H] mice display an entirely different phenotype, exhibiting autoimmunity, and severe inflammation of the skin and modest inflammation of the liver and lungs. Similar to mice with a Treg-specific knockout of TRAF6, or mice devoid of TRAF6 in all T cells, the CD4+ and CD8+ T cells in the spleen and lymph nodes displayed an activated effector memory phenotype with CD44high/CD62Llow expression on the cell surface. In contrast, T cells from WT mice exhibited the CD44low/CD62Lhigh phenotype characteristic of naïve T cells. The onset of autoimmunity and autoinflammation in TRAF6[L74H] mice (two weeks) was much faster than in mice with a Treg-specific knockout of TRAF6 or lacking TRAF6 expression in all T cells (2-3 months) and we discuss whether this may be caused by secondary inflammation of other tissues. The distinct phenotypes of mice lacking TRAF6 expression in all cells appears to be explained by their inability to signal via TNF Receptor Superfamily members, which does not seem to be impaired significantly in TRAF6[L74H] mice.

Intratumoral IL-1R1 expression delineates a distinctive molecular subset with therapeutic resistance in patients with gastric cancer.

BACKGROUND: With the essential role of interleukin-1 signaling in cancer-related inflammation, IL-1R1, the main receptor for both IL-1α and IL-1ß, demonstrated therapeutic potential in several types of cancer, which has been put into clinical trials. However, the expression profile and critical role of IL-1R1 in gastric cancer (GC) remain obscure. This study aimed to investigate the prognostic significance of IL-1R1 expression and its predictive value for chemotherapy and immunotherapy in GC. METHODS: The study enrolled three cohorts, consisting of 409 tumor microarray specimens of GC patients from Zhongshan Hospital, 341 transcriptional data from The Cancer Genome Atlas, and 45 transcriptional data from patients treated with pembrolizumab. IL-1R1 mRNA expression was directly acquired from public datasets, and we also detected IL-1R1 protein expression on tumor microarray by immunohistochemistry. Finally, the associations of IL-1R1 expression with clinical outcomes, immune contexture, and genomic features were analyzed. RESULTS: High IL-1R1 expression predicted poor prognosis and inferior responsiveness to both 5-fluorouracil-based adjuvant chemotherapy (ACT) and immune checkpoint blockade (ICB). IL-1R1 fostered an immunosuppressive microenvironment characterized by upregulated M2 macrophages and exhausted CD8+ T cells infiltration. Moreover, the expression of IL-1R1 was intrinsically linked to genomic alterations associated with targeted therapies in GC. CONCLUSIONS: IL-1R1 served as an independent prognosticator and predictive biomarker for ACT and ICB in GC. Furthermore, IL-1R1 antagonists could be a novel agent alone or combined with current therapeutic strategies in GC.

Early alveolar macrophage response and IL-1R-dependent T cell priming determine transmissibility of Mycobacterium tuberculosis strains.

Mechanisms underlying variability in transmission of Mycobacterium tuberculosis strains remain undefined. By characterizing high and low transmission strains of M.tuberculosis in mice, we show here that high transmission M.tuberculosis strain induce rapid IL-1R-dependent alveolar macrophage migration from the alveolar space into the interstitium and that this action is key to subsequent temporal events of early dissemination of bacteria to the lymph nodes, Th1 priming, granulomatous response and bacterial control. In contrast, IL-1R-dependent alveolar macrophage migration and early dissemination of bacteria to lymph nodes is significantly impeded in infection with low transmission M.tuberculosis strain; these events promote the development of Th17 immunity, fostering neutrophilic inflammation and increased bacterial replication. Our results suggest that by inducing granulomas with the potential to develop into cavitary lesions that aids bacterial escape into the airways, high transmission M.tuberculosis strain is poised for greater transmissibility. These findings implicate bacterial heterogeneity as an important modifier of TB disease manifestations and transmission.

The interleukin-1 receptor type I promotes the development of aging-associated cardiomyopathy in mice.

BACKGROUND: Aging is associated with metabolic and structural changes causing heart failure with preserved ejection fraction (HFpEF). Interleukin-1 (IL-1) is a pro-inflammatory cytokine involved in aging-related inflammation. OBJECTIVE: We sought to determine whether IL-1 mediates aging-related changes in the heart, as seen in HFpEF. METHODS: We studied age-matched young (4-month-old), middle-aged (14-month-old), and old (23-month-old) wild-type (WT) C57BL/6J and IL-1 receptor type I deficient (IL1RI-KO) male mice. Echocardiography was used to evaluate left ventricular (LV) dimensions and systolic/diastolic function, and a pressure transducer was used to measure the LV end-diastolic pressure. Picrosirius red stain was used to assess for myocardial interstitial fibrosis (MIF) at pathology. RESULTS: WT and IL-1RIKO mice showed a normal cardiac phenotype at young age, without any differences between the two groups. With aging, the WT mice developed LV concentric hypertrophy (as measured by a significant increase in LV mass [+42%, P < 0.01] and relative wall thickness [+34%, P < 0.01]), whereas the aging IL-1RI-KO mice did not. With aging, the WT mice also developed diastolic dysfunction (as measured by a significant increase in isovolumetric relaxation time [+148%, P < 0.01] and a significantly higher LV end-diastolic pressure [+174%, P < 0.01]), whereas the aging IL1RI-KO did not. Aged WT mice showed a significant increase in MIF (+124%, P < 0.01) at cardiac pathology, whereas the aging IL-1RI-KO did not. CONCLUSIONS: Genetically-modified mice lacking the IL-1RI receptor, not responsive to IL-1, are protected from aging-related LV hypertrophy, fibrosis, and diastolic dysfunction. These data support a central role of IL-1 in the pathophysiology of aging-related HFpEF.

Glycan-mediated functional assembly of IL-1RI: structural insights into completion of the current description for immune response.

Interleukin 1 Receptor type I (IL-1RI) is a multi-domain transmembrane receptor that triggers the inflammatory response. Understanding its detailed mechanism of action is crucial for treating immune disorders. IL-1RI is activated upon formation of its functional assembly that occurs by binding of the IL-1 cytokine and the accessory protein (Il-1RAcP) to it. X-ray crystallography, small-Angle X-ray Scattering and molecular dynamics simulation studies showed that IL-1RI adopts two types of 'compact' and 'extended' conformational states in its dynamical pattern. Furthermore, glycosylation has shown to play a critical role in its activation process. Here, classical and accelerated atomistic molecular dynamics were carried out to examine the role of full glycosylation of IL-1RI and IL-1RAcP in arrangement of the functional assembly. Simulations showed that the 'compact' and 'extended' IL-1RI form two types of 'cytokine-inaccessible-non-signaling' and 'cytokine-accessible-signaling' assemblies with the IL-1RacP, respectively that are both abiding in the presence of glycans. Suggesting that the cytokine binding to IL-1RI is not required for the formation of IL-1RI-IL-1RAcP complex and the 'compact' complex could act as a down-regulatory mechanism. The 'extended' complex is maintained by formation of several persistent hydrogen bonds between the IL-1RI-IL-1RAcP inter-connected glycans. Taken together, it was shown that full glycosylation regulates formation of the IL-1RI functional assembly and play critical role in cytokine biding and triggering the IL-1RI involved downstream pathways in the cell.Communicated by Ramaswamy H. Sarma.

IL-1 receptor signaling in podocytes limits susceptibility to glomerular damage.

Interleukin (IL)-1 receptor type 1 (IL-1R1) activation triggers a proinflammatory signaling cascade that can exacerbate kidney injury. However, the functions of podocyte IL-1R1 in glomerular disease remain unclear. To study the role of IL-1R1 signaling in podocytes, we selectively ablated podocyte IL-1R1 in mice (PKO mice). We then subjected PKO mice and wild-type controls to two glomerular injury models: nephrotoxic serum (NTS)- and adriamycin-induced nephropathy. Surprisingly, we found that IL-1R1 activation in podocytes limited albuminuria and podocyte injury during NTS- and adriamycin-induced nephropathy. Moreover, deletion of IL-1R1 in podocytes drove podocyte apoptosis and glomerular injury through diminishing Akt activation. Activation of Akt signaling abrogated the differences in albuminuria and podocyte injury between wild-type and PKO mice during NTS. Thus, IL-1R1 signaling in podocytes limits susceptibility to glomerular injury via an Akt-dependent signaling pathway. These data identify an unexpected protective role for IL-1R1 signaling in podocytes in the pathogenesis of glomerular disease.NEW & NOTEWORTHY The present study establishes that activation of the receptor for interleukin-1 limits susceptibility to damage to the kidney glomerulus in preclinical mouse models by stimulating Akt signaling cascades inside the podocyte.

Molecular mechanisms in IL-1ß-mediated decorin production by decidual cells.

Decorin, a small leucine-rich proteoglycan produced by decidual cells restrains trophoblast differentiation, migration and invasiveness of extra-villous trophoblast cells. Decidual overproduction of decorin is associated with preeclampsia, and elevated decorin levels in maternal plasma are a predictive biomarker of preeclampsia. Furthermore, decorin plays an autocrine role in maturation of human endometrial stromal cells into decidual cells. Thus, a balanced decorin production by the decidua is critical for healthy pregnancy. However, the molecular mechanisms regulating decorin production by the decidua are unclear. Interleukin-1 beta is an inflammation-associated multi-functional cytokine, and is reported to induce decidualization in primates. Hence, the present study was designed: (i) to test if exogenous Interleukin-1 beta stimulated decorin production by human endometrial stromal cells; and if so, (ii) to identify the cellular source of Interleukin-1 beta in first trimester decidual tissue; (iii) to identify the downstream molecular partners in Interleukin-1 beta mediated decorin production by human endometrial stromal cells. Results revealed that (i) amongst multiple pro-inflammatory cytokines tested, Interleukin-1 beta alone stimulated decorin production by these cells; (ii) both macrophages and decidual cells in first trimester decidua produced Interleukin-1 beta; (iii) Interleukin-1 beta mediated decorin production was dependent on Interleukin-1 receptor activation, followed by activation and nuclear translocation of nuclear factor kappa B and its binding to the decorin promoter. These results reveal that Interleukin-1 beta plays a novel role in inducing decorin production by human endometrial stromal cells by activating nuclear factor kappa B.

NLRP2 Is Overexpressed in Spinal Astrocytes at the Peak of Mechanical Pain Sensitivity during Complete Freund Adjuvant-Induced Persistent Pain.

Our earlier findings revealed that interleukin-1 receptor type-1 (IL-1R1) was overexpressed in spinal neurons, and IL-1R1-deficient mice showed significant attenuation of thermal and mechanical allodynia during the course of the Complete Freund adjuvant (CFA)-induced persistent pain model. In the present study, we found that a ligand of IL-1R1, termed interleukin-1ß (IL-1ß), is also significantly overexpressed at the peak of mechanical pain sensitivity in the CFA-evoked pain model. Analysis of cellular distribution and modeling using IMARIS software showed that in the lumbar spinal dorsal horn, IL-1ß is significantly elevated by astrocytic expression. Maturation of IL-1ß to its active form is facilitated by the formation of the multiprotein complex called inflammasome; thus, we tested the expression of NOD-like receptor proteins (NLRPs) in astrocytes. At the peak of mechanical allodynia, we found expression of the NLRP2 inflammasome sensor and its significantly elevated co-localization with the GFAP astrocytic marker, while NLRP3 was moderately present and NLRP1 showed total segregation from the astrocytic profiles. Our results indicate that peripheral CFA injection induces NLRP2 inflammasome and IL-1ß expression in spinal astrocytes. The release of mature IL-1ß can contribute to the maintenance of persistent pain by acting on its neuronally expressed receptor, which can lead to altered neuronal excitability.

Bioactive compounds and therapeutic role of Brassica oleracea L. seeds in rheumatoid arthritis rats via regulating inflammatory signalling pathways and antagonizing interleukin-1 receptor action.

CONTEXT: Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by aggressive and systematic polyarthritis. OBJECTIVE: The present study aimed to isolate and identify the phenolic constituents in Brassica oleracea L. (Brassicaceae) seeds methanolic extract and evaluates its effect against rheumatoid arthritis in rats referring to the new therapy; interleukin-1 receptor antagonist (IL-1RA). MATERIALS AND METHODS: The GC/MS profiling of the plant was determined. Arthritis induction was done using complete Freund's adjuvant. Arthritis severity was assessed by percentage of edema and arthritis index. IL-1 receptor type I gene expression, interleukin-1ß (IL-1ß), oxidative stress markers, protein content, inflammatory mediators, prostaglandin-E2 (PGE2), genetic abnormalities and the histopathological features of ankle joint were evaluated. RESULTS: For the first time twelve phenolic compounds had been isolated from the seeds extract. Treatment with extract and IL-1RA improved the tested parameters by variable degrees. CONCLUSIONS: RA is an irreversible disease, where its severity increases with the time of induction. Brassica oleracea L. seeds extract is considered as a promising anti-arthritis agent. IL-1 RA may be considered as an unusual therapeutic agent for RA disease. More studies are needed to consider the seeds extract as a nutraceutical agent and to recommend IL-1RA as a new RA drug.

NLRP3 Inflammasome Mediates Immune-Stromal Interactions in Vasculitis.

[Figure: see text].

Inflammatory Regulation of CNS Barriers After Traumatic Brain Injury: A Tale Directed by Interleukin-1.

Several barriers separate the central nervous system (CNS) from the rest of the body. These barriers are essential for regulating the movement of fluid, ions, molecules, and immune cells into and out of the brain parenchyma. Each CNS barrier is unique and highly dynamic. Endothelial cells, epithelial cells, pericytes, astrocytes, and other cellular constituents each have intricate functions that are essential to sustain the brain's health. Along with damaging neurons, a traumatic brain injury (TBI) also directly insults the CNS barrier-forming cells. Disruption to the barriers first occurs by physical damage to the cells, called the primary injury. Subsequently, during the secondary injury cascade, a further array of molecular and biochemical changes occurs at the barriers. These changes are focused on rebuilding and remodeling, as well as movement of immune cells and waste into and out of the brain. Secondary injury cascades further damage the CNS barriers. Inflammation is central to healthy remodeling of CNS barriers. However, inflammation, as a secondary pathology, also plays a role in the chronic disruption of the barriers' functions after TBI. The goal of this paper is to review the different barriers of the brain, including (1) the blood-brain barrier, (2) the blood-cerebrospinal fluid barrier, (3) the meningeal barrier, (4) the blood-retina barrier, and (5) the brain-lesion border. We then detail the changes at these barriers due to both primary and secondary injury following TBI and indicate areas open for future research and discoveries. Finally, we describe the unique function of the pro-inflammatory cytokine interleukin-1 as a central actor in the inflammatory regulation of CNS barrier function and dysfunction after a TBI.

Inhibition of MLKL-dependent necroptosis via downregulating interleukin-1R1 contributes to neuroprotection of hypoxic preconditioning in transient global cerebral ischemic rats.

BACKGROUND: Our previous study indicated that hypoxic preconditioning reduced receptor interacting protein (RIP) 3-mediated necroptotic neuronal death in hippocampal CA1 of adult rats after transient global cerebral ischemia (tGCI). Although mixed lineage kinase domain-like (MLKL) has emerged as a crucial molecule for necroptosis induction downstream of RIP3, how MLKL executes necroptosis is not yet well understood. In this study, we aim to elucidate the molecular mechanism underlying hypoxic preconditioning that inactivates MLKL-dependent neuronal necroptosis after tGCI. METHODS: Transient global cerebral ischemia was induced by the four-vessel occlusion method. Twenty-four hours before ischemia, rats were exposed to systemic hypoxia with 8% O2 for 30 min. Western blotting was used to detect the expression of MLKL and interleukin-1 type 1 receptor (IL-1R1) in CA1. Immunoprecipitation was used to assess the interactions among IL-1R1, RIP3, and phosphorylated MLKL (p-MLKL). The concentration of intracellular free calcium ion (Ca2+) was measured using Fluo-4 AM. Silencing and overexpression studies were used to study the role of p-MLKL in tGCI-induced neuronal death. RESULTS: Hypoxic preconditioning decreased the phosphorylation of MLKL both in neurons and microglia of CA1 after tGCI. The knockdown of MLKL with siRNA decreased the expression of p-MLKL and exerted neuroprotective effects after tGCI, whereas treatment with lentiviral delivery of MLKL showed opposite results. Mechanistically, hypoxic preconditioning or MLKL siRNA attenuated the RIP3-p-MLKL interaction, reduced the plasma membrane translocation of p-MLKL, and blocked Ca2+ influx after tGCI. Furthermore, hypoxic preconditioning downregulated the expression of IL-1R1 in CA1 after tGCI. Additionally, neutralizing IL-1R1 with its antagonist disrupted the interaction between IL-1R1 and the necrosome, attenuated the expression and the plasma membrane translocation of p-MLKL, thus alleviating neuronal death after tGCI. CONCLUSIONS: These data support that the inhibition of MLKL-dependent neuronal necroptosis through downregulating IL-1R1 contributes to neuroprotection of hypoxic preconditioning against tGCI.