RESUMEN
IL-18 is a pleiotropic immunoregulatory cytokine of the IL-1 family. IL-18 has been identified as a potent IFN-γ inducer in synergy with IL-12 and IL-15 and thus as a powerful Th1 cell-polarizing cytokine. IL-18 activity is regulated by its naturally occurring soluble inhibitor IL-18 binding protein (IL-18BP), the production of which is stimulated by IFN-γ in a negative feedback loop. Circulating levels of IL-18BP are elevated, and unbound bioactive free IL-18 is thus not detectable in the circulation in physiologic conditions. However, emerging evidence indicates that the IL-18/IL-18BP balance could be dysregulated in macrophage activation syndrome (MAS), as mirrored by the presence of free IL-18 in the circulation of patients with MAS. Herein, we sought to identify IL-18BP-producing cells in a murine CpG-induced MAS model using IL-18BP knock-in tdTomato reporter mice. Endothelial cells, tissue-resident macrophages, and neutrophils appeared as major cellular sources of IL-18BP. We also identified extramedullary and medullary early erythroid progenitors as IL-18BP-producing cells in an IFN-γ-dependent manner. This finding suggests a novel regulation of IL-18 activity by erythroid precursors, which are likely involved in the prevention of the negative effects of IL-18 on erythropoiesis. Indeed, coherent in vivo and in vitro results indicate that IL-18 indirectly impairs erythropoiesis while favoring myelopoiesis and thus contributes to anemia associated with MAS and potentially with other IL-18-driven inflammatory diseases. In conclusion, IL-18BP production by endothelial cells, neutrophils, macrophages, and erythroid precursors attenuates the anemia associated with murine CpG-induced MAS.
Asunto(s)
Anemia , Síndrome de Activación Macrofágica , Animales , Ratones , Proteínas Portadoras , Citocinas/metabolismo , Células Endoteliales/metabolismo , Interleucina-18/metabolismoRESUMEN
Helicobacter pylori (H. pylori) infection can trigger chronic gastric inflammation perpetuated by overactivation of the innate immune system, leading to a cascade of precancerous lesions culminating in gastric cancer. However, key regulators of innate immunity that promote H. pylori-induced gastric pathology remain ill-defined. The innate immune cytosolic DNA sensor absent in melanoma 2 (AIM2) contributes to the pathogenesis of numerous autoimmune and chronic inflammatory diseases, as well as cancers including gastric cancer. We therefore investigated whether AIM2 contributed to the pathogenesis of Helicobacter-induced gastric disease. Here, we reveal that AIM2 messenger RNA and protein expression levels are elevated in H. pylori-positive versus H. pylori-negative human gastric biopsies. Similarly, chronic Helicobacter felis infection in wild-type mice augmented Aim2 gene expression levels compared with uninfected controls. Notably, gastric inflammation and hyperplasia were less severe in H. felis-infected Aim2-/- versus wild-type mice, evidenced by reductions in gastric immune cell infiltrates, mucosal thickness and proinflammatory cytokine and chemokine release. In addition, H. felis-driven proliferation and apoptosis in both gastric epithelial and immune cells were largely attenuated in Aim2-/- stomachs. These observations in Aim2-/- mouse stomachs correlated with decreased levels of inflammasome activity (caspase-1 cleavage) and the mature inflammasome effector cytokine, interleukin-1ß. Taken together, this work uncovers a pathogenic role for the AIM2 inflammasome in Helicobacter-induced gastric disease, and furthers our understanding of the host immune response to a common pathogen and the complex and varying roles of AIM2 at different stages of cancerous and precancerous gastric disease.
Asunto(s)
Felis , Helicobacter , Lesiones Precancerosas , Neoplasias Gástricas , Animales , Humanos , Ratones , Citocinas/metabolismo , Proteínas de Unión al ADN/metabolismo , Felis/metabolismo , Mucosa Gástrica/metabolismo , Mucosa Gástrica/patología , Helicobacter/metabolismo , Inflamasomas/metabolismo , Inflamación/patología , Lesiones Precancerosas/patologíaRESUMEN
IL-18 binding protein (IL-18BP) acts as a naturally occurring IL-18 decoy receptor. If the balance between IL-18 and IL-18BP is dysregulated, abnormal levels of free bioactive IL-18 are detected, such as in the sera of Il-18bp knockout (KO) mice with CpG-induced macrophage activation syndrome. To determine the cellular sources of Il-18bp in vivo, we selectively depleted Il-18bp expression in either radiosensitive or radioresistant cells using bone marrow transfer between wild-type (WT) and Il-18bp KO mice. Following repeated CpG injections, Il-18bp KO (donor)â Il-18bp KO (recipient) chimeric mice exhibited more severe disease, with an enhanced Ifn-γ signature and circulating free Il-18 levels, in comparison with WTâWT chimeras. Interestingly, the phenotype of KOâWT and WTâKO mice did not differ from that of WTâWT mice. Consistent with this finding, serum Il-18bp levels were similar in these three groups of mice. The contribution of radioresistant and radiosensitive cells to Il-18bp production varied markedly according to the organ examined, with a major contribution of radiosensitive cells in the spleen as opposed to a major contribution of radioresistant cells in the lung. Finally, Ifn-γ blockade abrogated the CpG-induced but not the constitutive Il-18bp production. Our results demonstrate that circulating Il-18bp is induced in response to Ifn-γ during CpG-induced macrophage activation syndrome and is present at high levels in the circulation to prevent the deleterious systemic effects of Il-18.
Asunto(s)
Proteínas Portadoras/metabolismo , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Interleucina-18/metabolismo , Síndrome de Activación Macrofágica/metabolismo , Animales , Femenino , Interferón gamma/metabolismo , Pulmón/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Bazo/metabolismoRESUMEN
The inflammatory effects of IL-1α/ß are controlled by IL-1R antagonist (IL-1Ra). One IL-1Ra isoform is secreted, whereas three other isoforms (intracellular IL-1Ra [icIL-1Ra] 1, 2, and 3) are supposed to remain intracellular because of the absence of a signal peptide. In contrast to the well-characterized function of the secreted isoform, the biological role of the intracellular isoforms remains largely unclear. icIL-1Ra1 represents the major isoform in keratinocytes. We created icIL-1Ra1-/- mice and investigated the role of icIL-1Ra1 in Aldara (5% imiquimod)-induced psoriasis-like skin inflammation. Naive icIL-1Ra1-/- mice bred habitually and exhibited a normal phenotype. icIL-1Ra1 deficiency aggravated Aldara-induced skin inflammation, as demonstrated by increased ear thickness and increased mRNA levels of key proinflammatory cytokines. No intracellular effect of icIL-1Ra1 could be detected in isolated keratinocytes using RNA-sequencing analysis; however, Aldara treatment led to caspase 1/11-, caspase 8-, and RIPK3-independent keratinocyte cell death accompanied by the release of both icIL-1Ra1 and IL-1α. Furthermore, blocking IL-1α attenuated the clinical severity of Aldara-induced ear thickening in icIL-1Ra1-/- mice. Our data suggest that upon keratinocyte damage icIL-1Ra1 acts extracellularly as an antagonist of the alarmin IL-1α to immediately counteract its inflammatory effects.
Asunto(s)
Alarminas/antagonistas & inhibidores , Apoptosis/inmunología , Proteína Antagonista del Receptor de Interleucina 1/metabolismo , Interleucina-1alfa/antagonistas & inhibidores , Psoriasis/inmunología , Alarminas/inmunología , Alarminas/metabolismo , Animales , Modelos Animales de Enfermedad , Femenino , Humanos , Imiquimod/inmunología , Proteína Antagonista del Receptor de Interleucina 1/inmunología , Interleucina-1alfa/inmunología , Interleucina-1alfa/metabolismo , Queratinocitos/metabolismo , Masculino , Ratones , Ratones Noqueados , Isoformas de Proteínas/inmunología , Isoformas de Proteínas/metabolismo , Psoriasis/diagnóstico , Psoriasis/patología , Índice de Severidad de la Enfermedad , Transducción de Señal/inmunología , Piel/citología , Piel/inmunología , Piel/patologíaRESUMEN
The term macrophage activation syndrome (MAS) defines a severe, potentially fatal disorder characterized by overwhelming inflammation and multiorgan involvement. Interleukin-18 (IL-18) is a proinflammatory cytokine belonging to the IL-1 family, the activity of which is regulated by its endogenous inhibitor IL-18 binding protein (IL-18BP). Elevated IL-18 levels have been reported in patients with MAS. Herein, we show that on repeated toll-like receptor 9 (TLR9) stimulation with unmethylated cytosine guanine dinucleotide containing single-stranded DNA (CpG), IL-18BP-/- mice display severe MAS manifestations, including increased weight loss, splenomegaly, anemia, thrombocytopenia, hyperferritinemia, and bone marrow hemophagocytosis as compared with wild-type mice. Serum-free IL-18 was detected in CpG-treated IL-18BP-/- mice only. Levels of interferon-γ (IFN-γ) and of IFN-γ signature genes, such as the chemokine Cxcl9 or the transcription factor CIIta, were significantly increased in IL-18BP-/- mice. Blocking IL-18 receptor signaling attenuated the severity of MAS and IFN-γ responses in IL-18BP-/- mice. Blocking IFN-γ had comparable effects to IL-18 inhibition on most MAS manifestations. Our data indicate that endogenous IL-18BP exerts a protective role in CpG-induced MAS and that IL-18, which acts upstream of IFN-γ, is involved in the severity of MAS.
Asunto(s)
Interleucina-18/inmunología , Síndrome de Activación Macrofágica/inmunología , Transducción de Señal/inmunología , Receptor Toll-Like 9/inmunología , Animales , Quimiocina CXCL9/genética , Quimiocina CXCL9/inmunología , Péptidos y Proteínas de Señalización Intercelular/genética , Péptidos y Proteínas de Señalización Intercelular/inmunología , Interferón gamma/genética , Interferón gamma/inmunología , Interleucina-18/genética , Síndrome de Activación Macrofágica/inducido químicamente , Síndrome de Activación Macrofágica/genética , Síndrome de Activación Macrofágica/patología , Ratones , Ratones Noqueados , Proteínas Nucleares/genética , Proteínas Nucleares/inmunología , Oligodesoxirribonucleótidos/efectos adversos , Oligodesoxirribonucleótidos/farmacología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Receptor Toll-Like 9/agonistas , Receptor Toll-Like 9/genética , Transactivadores/genética , Transactivadores/inmunologíaRESUMEN
The biological activity of IL-1 is tightly regulated by the specific receptor antagonist (IL-1Ra) and the decoy receptor IL-1 receptor type 2 (IL-1R2). The role of IL-1Ra has been well demonstrated in IL-1Ra-deficient mice. In contrast, the role of endogenous IL-1R2 remains widely unknown. To define the functional role of endogenous IL-1R2 in the K/BxN serum transfer arthritis model and in IL-1ß- or LPS-induced systemic inflammation in vivo, IL-1R2-/- mice were created and compared with wild type mice. IL-1R2-/- mice bred habitually and exhibited a normal phenotype. IL-1R2 deficiency aggravated arthritis severity and increased mRNA levels for key cytokines and chemokines such as IL-6, IL-1ß, Cxcl-1, and Cxcl-2 significantly in ankles. There was no effect of IL-1R2 deficiency on the cell-autonomous cytokine response to IL-1ß in the tested cell types, i.e., neutrophils, macrophages, and fibroblasts, but IL-1R2 deficiency on neutrophils increased the IL-1-induced response of fibroblasts in trans. Furthermore, IL-1ß induced shedding of IL-1R2 in vivo. Inflammatory responses to IL-1ß and LPS-induced mortality were not different in IL-1R2-/- compared with wild type mice. Our data demonstrate that the decoy receptor IL-1R2 plays an important inhibitory role in local IL-1- and neutrophil-dependent tissue inflammation as shown in the K/BxN serum transfer arthritis model. In contrast to IL-1Ra, IL-1R2 appears to be less crucial for systemic responses to acute administration of IL-1 or LPS.
Asunto(s)
Artritis Experimental/inmunología , Inflamación/inmunología , Receptores Tipo II de Interleucina-1/inmunología , Animales , Inmunohistoquímica , Ratones , Ratones Noqueados , Reacción en Cadena en Tiempo Real de la PolimerasaRESUMEN
Human and mouse neonates exhibit limited vaccine responses characterized by predominant Th2 and limited Th1 responses. Because IL-36 exerts a synergic adjuvant effect with IL-12, enhancing Th1 polarization in adult (AD) mice, we administered IL-36ß to neonatal (1-wk old) and AD control mice at the time of immunization with tetanus toxoid adsorbed to aluminum hydroxide (TT/Alum). Unexpectedly, the combination of IL-36ß with TT/Alum, which was well tolerated in AD mice, proved toxic and even lethal in neonates. This neonatal toxicity was associated with high Il36r mRNA expression in neonatal liver, resulting in increased cytokine production. Liver Il36r mRNA expression decreased with the termination of fetal liver hematopoiesis, and this decrease correlated with a complete protection from TT/Alum/IL-36ß-induced mortality. The combination of IL-36ß and TT/Alum induced the rapid production of TNF-α and IFN-γ by liver myeloid and lymphoid cells, respectively. These responses were less marked when IL-36ß was used alone, with no adverse effect. The toxicity of IL-36ß + TT/Alum was abrogated by the administration of a neutralizing anti-TNF-α Ab, confirming causality. In conclusion, liver myeloid cells in neonatal mice are an important source of proinflammatory cytokines that may lead to TNF-α-mediated toxicity and even lethality.
Asunto(s)
Interleucina-1/toxicidad , Hígado/inmunología , Células Mieloides/inmunología , Factor de Necrosis Tumoral alfa/biosíntesis , Animales , Animales Recién Nacidos , Citocinas/biosíntesis , Ratones , Ratones Endogámicos C57BL , Toxoide Tetánico/toxicidadRESUMEN
The interleukin-1 (IL-1) superfamily of cytokines comprises a set of pivotal mediators of inflammation. Among them, the action of IL-36 cytokines in immune responses has remained elusive. In a recent study, we demonstrated a direct effect of IL-36 on immune cells. Here we show that, among T cells, the IL-36 receptor is predominantly expressed on naive CD4(+) T cells and that IL-36 cytokines act directly on naive T cells by enhancing both cell proliferation and IL-2 secretion. IL-36ß acts in synergy with IL-12 to promote Th1 polarization and IL-36 signaling is also involved in mediating Th1 immune responses to Bacillus Calmette-Guerin infection in vivo. Our findings point toward a critical function of IL-36 in the priming of Th1 cell responses in vitro, and in adaptive immunity in a model of mycobacterial infection in vivo.
Asunto(s)
Mycobacterium bovis/inmunología , Receptores de Interleucina-1/inmunología , Transducción de Señal/inmunología , Células TH1/inmunología , Tuberculosis/metabolismo , Tuberculosis/veterinaria , Inmunidad Adaptativa , Animales , Diferenciación Celular , Proliferación Celular , Interleucina-1/inmunología , Interleucina-1/farmacología , Interleucina-12/inmunología , Interleucina-12/farmacología , Interleucina-2/biosíntesis , Interleucina-2/inmunología , Activación de Linfocitos , Ratones , Ratones Noqueados , Cultivo Primario de Células , Receptores de Interleucina-1/deficiencia , Receptores de Interleucina-1/genética , Transducción de Señal/genética , Células TH1/citología , Células TH1/microbiología , Tuberculosis/genética , Tuberculosis/inmunologíaRESUMEN
Psoriasis is a common chronic inflammatory skin disease that significantly impacts the patients' quality of life. Recent studies highlighted the function of the interleukin (IL)-1 family member IL-38 in skin homeostasis and suggested an anti-inflammatory role for this cytokine in psoriasis. In this study, we generated mice specifically overexpressing the IL-38 protein in epidermal keratinocytes. We confirmed IL-38 overexpression in the skin by Western blotting. We further detected the protein by ELISA in the plasma, as well as in conditioned media of skin explants isolated from IL-38 overexpressing mice, indicating that IL-38 produced in the epidermis is released from keratinocytes and can be found in the circulation. Unexpectedly, epidermal IL-38 overexpression did not impact the global severity of imiquimod (IMQ)-induced skin inflammation, Similarly, keratinocyte activation and differentiation in IMQ-treated skin were not affected by increased IL-38 expression and there was no global effect on local or systemic inflammatory responses. Nevertheless, we observed a selective inhibition of CXCL1 and IL-6 production in response to IMQ in IL-38 overexpressing skin, as well as reduced Ly6g mRNA levels, suggesting decreased neutrophil infiltration. Epidermal IL-38 overexpression also selectively affected the desquamation process during IMQ-induced psoriasis, as illustrated by reduced plaque formation. Taken together, our results validate the generation of a new mouse line allowing for tissue-specific IL-38 overexpression. Interestingly, epidermal IL-38 overexpression selectively affected specific disease-associated readouts during IMQ-induced psoriasis, suggesting a more complex role of IL-38 in the inflamed skin than previously recognized. In particular, our data highlight a potential involvement of IL-38 in the regulation of skin desquamation.
Asunto(s)
Imiquimod , Interleucina-1 , Queratinocitos , Psoriasis , Animales , Queratinocitos/metabolismo , Queratinocitos/inmunología , Ratones , Psoriasis/inducido químicamente , Psoriasis/inmunología , Psoriasis/metabolismo , Interleucina-1/metabolismo , Interleucina-1/genética , Piel/inmunología , Piel/patología , Piel/metabolismo , Modelos Animales de Enfermedad , Ratones Transgénicos , Ratones Endogámicos C57BLRESUMEN
Interleukin-1 receptor antagonist (IL-1Ra) is a specific IL-1 inhibitor that possesses anti-inflammatory activities. Several studies in human and mouse suggested a protective role for IL-1Ra in liver inflammation, and we previously demonstrated that hepatocytes produce high levels of IL-1Ra in response to inflammatory challenge in vitro and in vivo. In the present study, we investigated the production and the biological function of hepatocyte-derived IL-1Ra in concanavalin A (ConA)-induced hepatitis in mice. We show that the injured liver produces large amounts of IL-1Ra and that secreted and intracellular IL-1Ra isoforms are produced with different kinetics during the course of hepatitis. By using hepatocyte-specific IL-1Ra-deficient mice (IL-1Ra(ΔH)), we demonstrate that hepatocytes represent the major cellular source of local IL-1Ra. Most interestingly, hepatic necrosis and inflammation were increased in IL-1Ra(ΔH) as compared with wild-type mice during the late phase of the disease, leading to a delayed resolution of hepatitis in IL-1Ra(ΔH) mice. In conclusion, our results show that the local production of IL-1Ra by hepatocytes contributes to the resolution of hepatitis.
Asunto(s)
Hepatitis/inmunología , Hepatocitos/inmunología , Proteína Antagonista del Receptor de Interleucina 1/inmunología , Animales , Concanavalina A/toxicidad , Citocinas/análisis , Hepatitis/genética , Hepatitis/patología , Hepatocitos/efectos de los fármacos , Proteína Antagonista del Receptor de Interleucina 1/genética , Hígado/inmunología , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Necrosis/inmunologíaRESUMEN
IL-36α (IL-1F6), IL-36ß (IL-1F8), and IL-36γ (IL-1F9) are members of the IL-1 family of cytokines. These cytokines bind to IL-36R (IL-1Rrp2) and IL-1RAcP, activating similar intracellular signals as IL-1, whereas IL-36Ra (IL-1F5) acts as an IL-36R antagonist (IL-36Ra). In this study, we show that both murine bone marrow-derived dendritic cells (BMDCs) and CD4(+) T lymphocytes constitutively express IL-36R and respond to IL-36α, IL-36ß, and IL-36γ. IL-36 induced the production of proinflammatory cytokines, including IL-12, IL-1ß, IL-6, TNF-α, and IL-23 by BMDCs with a more potent stimulatory effect than that of other IL-1 cytokines. In addition, IL-36ß enhanced the expression of CD80, CD86, and MHC class II by BMDCs. IL-36 also induced the production of IFN-γ, IL-4, and IL-17 by CD4(+) T cells and cultured splenocytes. These stimulatory effects were antagonized by IL-36Ra when used in 100- to 1000-fold molar excess. The immunization of mice with IL-36ß significantly and specifically promoted Th1 responses. Our data thus indicate a critical role of IL-36R ligands in the interface between innate and adaptive immunity, leading to the stimulation of T helper responses.
Asunto(s)
Células Dendríticas/efectos de los fármacos , Ligandos , Receptores de Interleucina-1/agonistas , Receptores de Interleucina/agonistas , Linfocitos T/efectos de los fármacos , Animales , Células de la Médula Ósea/efectos de los fármacos , Células de la Médula Ósea/metabolismo , Células de la Médula Ósea/fisiología , Células Cultivadas , Células Dendríticas/metabolismo , Células Dendríticas/fisiología , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos , Interleucina-1/farmacología , Interleucina-1/fisiología , Interleucinas/farmacología , Interleucinas/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Receptores de Interleucina/antagonistas & inhibidores , Receptores de Interleucina/genética , Receptores de Interleucina/metabolismo , Receptores de Interleucina-1/genética , Receptores de Interleucina-1/metabolismo , Linfocitos T/metabolismo , Linfocitos T/fisiologíaRESUMEN
The cytokine interleukin-1α (IL-1α) is synthesized as a 31kDa peptide that lacks a leader peptide and is not secreted by the conventional secretory pathway. A distinctive characteristic of pro-IL-1α is the presence of a nuclear localization sequence in its amino-terminal moiety that allows its translocation to the nucleus. However no nuclear function(s) of the endogenous pro-IL-1α has been reported to date. In the present study, we used murine macrophages that produce IL-1α in response to pro-inflammatory stimuli, to gain further insight into the biology of the endogenous IL-1α protein in innate immune cells. We show that endogenous IL-1α is essentially found as a chromatin-associated nuclear protein in LPS-stimulated macrophages. In contrast to IL-1ß, IL-1α was not released upon inflammasome activation unless significant cell damage occurred. IL-1ß mRNA and protein levels were specifically decreased in IL-1α deficient macrophages after LPS stimulation. However, overexpression of human pro-IL-1α did not rescue this defective IL-1ß production, suggesting that this finding might be related to the insertion of the targeting construct into the IL-1 locus, rather than to a specific nuclear function of pro-IL-1α. Finally, by using both genomic and proteomic approaches, we could not identify a nuclear function of IL-1α. Taken together, these observations suggest that in macrophages IL-1α primarily acts as an alarmin that is rapidly released upon cell damage to activate early mechanisms of host defense.
Asunto(s)
Interleucina-1alfa/metabolismo , Interleucina-1beta/metabolismo , Macrófagos/metabolismo , Animales , Línea Celular , Núcleo Celular , Cromatina/metabolismo , Humanos , Inmunidad Innata , Inflamasomas/inmunología , Inflamasomas/metabolismo , Interleucina-1alfa/deficiencia , Interleucina-1alfa/genética , Interleucina-1beta/biosíntesis , Lipopolisacáridos , Activación de Macrófagos , Macrófagos/inmunología , Ratones , Ratones Endogámicos C57BL , Ratones NoqueadosRESUMEN
Background: The pathogenesis of rheumatoid arthritis (RA) is believed to initiate at mucosal sites. The so-called 'mucosal origin hypothesis of RA' postulates an increased intestinal permeability before disease onset. Several biomarkers, including lipopolysaccharide binding protein (LBP) and intestinal fatty acid binding protein (I-FABP), have been proposed to reflect gut mucosa permeability and integrity, while serum calprotectin is a new inflammation marker proposed in RA. Methods: We analyzed serum samples of individuals genetically at increased risk of RA in a nested-case-control study. Participants from a longitudinal cohort of first-degree relatives of RA patients (SCREEN-RA cohort) were divided into three pre-clinical stages of RA, based on the presence of risk factors for subsequent RA onset: 1) low-risk healthy asymptomatic controls; 2) intermediate-risk individuals without symptoms, but with RA-associated auto-immunity; 3) high-risk individuals with clinically suspect arthralgias. Five patients with newly diagnosed RA were also sampled. Serum LBP, I-FABP and calprotectin were measured using commercially available ELISA kits. Results: We included 180 individuals genetically at increased risk for RA: 84 asymptomatic controls, 53 individuals with RA-associated autoimmunity and 38 high risk individuals. Serum LBP, I-FAPB or calprotectin concentrations did not differ between individuals in different pre-clinical stages of RA. Conclusion: Based on the serum biomarkers LBP, I-FABP and calprotectin, we could not detect any evidence for intestinal injury in pre-clinical stages of RA.
Asunto(s)
Artritis Reumatoide , Humanos , Estudios de Casos y Controles , Factores de Riesgo , Biomarcadores , Complejo de Antígeno L1 de LeucocitoRESUMEN
The interleukin (IL)-18 cytokine plays an important driver role in a range of autoimmune and inflammatory diseases, as well as cancer. IL-18 is a potent inducer of interferon gamma (IFN-γ), and the bioactivity of IL-18 is regulated by its natural soluble inhibitor, IL-18-binding protein (IL-18BP), which is present at high concentrations in the circulation. Many cell types have been described to secrete IL-18BP, constitutively or under the influence of IFN-γ, thus generating a negative feedback loop for IL-18. Therefore, solely measuring total IL-18 protein levels does not allow to evaluate its biological activity, especially in the context of systemic inflammatory diseases or other circumstances where IL-18BP is present (e.g., samples containing plasma, cells constitutively expressing IL-18BP). Considering there is a critical need to accurately measure the protein levels of both mature, biologically active IL-18 and IL-18BP as biomarkers of disease activity in patients and also stratification for potential anti-IL-18 therapy, in this chapter we provide the latest techniques to measure mature, free, and bioactive IL-18 and IL-18BP in different samples.
Asunto(s)
Citocinas , Interferón gamma , HumanosRESUMEN
Background: Interleukin-18 is a proinflammatory cytokine, the activity of which is regulated by its natural inhibitor, IL-18 binding protein (IL-18BP). Elevated circulating levels of IL-18 have been observed in patients with systemic juvenile idiopathic arthritis (sJIA) and adult-onset Still's disease (AOSD), two conditions associated with dysregulated innate immune responses. This study examines the expression and function of IL-18 and IL-18BP in K/BxN serum transfer arthritis (STA), a model that is uniquely dependent on innate immune responses. Methods: Naïve and serum transfer-induced arthritis (STA) wild-type (WT) mice were used to examine the articular levels of IL-18 and IL-18BP mRNA by RT-qPCR. The cellular sources of IL-18BP in the joints were determined by using Il18bp-tdTomato reporter knock-in mice. The incidence and severity of arthritis, including mRNA levels of different cytokines, were compared in IL-18BP or IL-18 knock-out (KO) mice and their WT littermates. Results: IL-18 and IL-18BP mRNA levels were significantly increased in arthritic as compared to normal joints. Synovial neutrophils, macrophages, and endothelial cells represented the cellular sources of IL-18BP in arthritic joints, whereas IL-18BP production was limited to endothelial cells in non-inflamed joints. The incidence and severity of arthritis were similar in IL-18BP KO and IL-18 KO compared to their WT littermates. Transcript levels of different inflammatory cytokines were not different in the two KO mouse lines compared to WT mice. Conclusion: Although IL-18 and IL-18BP levels were increased in arthritic joints, our results show that the IL-18/IL-18BP balance is not involved in the regulation of STA.
Asunto(s)
Interleucina-18 , Enfermedad de Still del Adulto , Animales , Ratones , Interleucina-18/genética , Interleucina-18/metabolismo , Células Endoteliales/metabolismo , Citocinas , ARN MensajeroRESUMEN
OBJECTIVES: To define the cell type (myeloid vs other cells) specific effect of interleukin 1 (IL-1) receptor antagonist (IL-1Ra) deficiency on the acute inflammatory phase of arthritis. METHODS: Arthritis was induced by K/BxN serum transfer in wild-type (WT), IL-1Ra-deficient (IL-1Ra(-/-)) and conditional knockout mice. In the latter, IL-1Ra production was specifically targeted in myeloid cells (IL-1Ra(ΔM)) or in both hepatocytes and myeloid cells (IL-1Ra(ΔH+M)). Arthritis severity was clinically evaluated and ankle sections were scored for synovial inflammation and cartilage erosion. Quantitative RT-PCR, western blot and immunohistochemical analyses measured expression, localisation and cellular sources of the different IL-1Ra isoforms in arthritic joints. RESULTS: Total and myeloid cell-specific IL-1Ra deficiency was associated with increased arthritis severity, although disease incidence was similar to that of WT mice. Increased clinical scores were associated with exacerbated synovial inflammation. All IL-1Ra isoforms, except for intracellular (ic)IL-1Ra2, were expressed in arthritic joints of WT mice. In contrast, production of secreted (s)IL-1Ra and icIL-1Ra3 isoforms was markedly decreased in arthritic joints of both IL-1Ra(ΔM) and IL-1Ra(ΔH+M) mice. Immunohistochemical and western blot analyses suggested that the icIL-1Ra1 isoform is produced primarily by synovial fibroblasts. CONCLUSION: Myeloid cell-derived IL-1Ra, including both sIL-1Ra and icIL-1Ra3 isoforms, controls articular inflammation during the acute phase of K/BxN serum transfer-induced arthritis.
Asunto(s)
Artritis Experimental/metabolismo , Proteína Antagonista del Receptor de Interleucina 1/fisiología , Células Mieloides/metabolismo , Enfermedad Aguda , Animales , Artritis Experimental/etiología , Artritis Experimental/patología , Cartílago Articular/patología , Progresión de la Enfermedad , Femenino , Proteína Antagonista del Receptor de Interleucina 1/deficiencia , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Isoformas de Proteínas/deficiencia , Isoformas de Proteínas/fisiología , Suero , Índice de Severidad de la Enfermedad , Sinovitis/metabolismo , Sinovitis/patologíaRESUMEN
IL-1R antagonist (IL-1Ra) is a natural inhibitor of the pleiotropic proinflammatory activities of IL-1. Although several reports described the effects of complete IL-1Ra deficiency, no study has examined the consequences of cell type-specific IL-1Ra inactivation during systemic inflammation. Previous in vitro data demonstrated high IL-1Ra production by hepatocytes and myeloid cells after endotoxin stimulation. In addition, hepatocyte IL-1Ra production is regulated as an acute-phase protein in vitro. In this study, we analyzed the production and functional role of hepatocyte- and myeloid cell-derived IL-1Ra during endotoxin-induced septic shock and acute IL-1beta-induced sterile inflammation. Using conditional IL-1Ra knockout mice, we showed that hepatocytes and myeloid cells are the two major cellular sources of circulating IL-1Ra in response to LPS. Interestingly, IL-1Ra production by myeloid cells, but not hepatocytes, is critical for survival during endotoxemia. Furthermore, we provide the first in vivo evidence demonstrating that IL-1Ra is produced as an acute-phase protein by hepatocytes during IL-1beta-induced inflammation and that hepatocyte-derived IL-1Ra functions as an endogenous negative feedback downregulating the proinflammatory effects of IL-1. Taken together, our observations define distinct roles for two major cellular sources of IL-1Ra in response to different types of systemic inflammatory stimuli in vivo.
Asunto(s)
Endotoxemia/sangre , Hepatocitos/metabolismo , Inflamación/sangre , Proteína Antagonista del Receptor de Interleucina 1/sangre , Células Mieloides/metabolismo , Proteínas de Fase Aguda/genética , Proteínas de Fase Aguda/fisiología , Animales , Endotoxemia/fisiopatología , Ensayo de Inmunoadsorción Enzimática , Femenino , Inmunohistoquímica , Inflamación/inducido químicamente , Inflamación/fisiopatología , Proteína Antagonista del Receptor de Interleucina 1/genética , Proteína Antagonista del Receptor de Interleucina 1/fisiología , Lipopolisacáridos , Hígado/metabolismo , Pulmón/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Bazo/metabolismo , Análisis de SupervivenciaRESUMEN
IL-36R signaling plays an important role in the pathogenesis of psoriasis. We ought to assess the specific function of IL-36R in keratinocytes for the pathology of Aldara-induced psoriasis-like dermatitis. Il36r ΔK mice presenting deletion of IL-36R in keratinocytes were similarly resistant to Aldara-induced ear inflammation as Il36r -/- mice, but acanthosis was only prevented in Il36r -/- mice. FACS analysis revealed that IL-36R signaling in keratinocytes is mandatory for early neutrophil infiltration in Aldara-treated ears. RNASeq and qRT-PCR experiments demonstrated the crucial role of IL-36R signaling in keratinocytes for induction of IL-23, IL-17, and IL-22 at early time points. Taken together, our results demonstrate that IL-36R signaling in keratinocytes plays a major role in the induction of Aldara-induced psoriasis-like dermatitis by triggering early production of IL-23/IL-17/IL-22 cytokines and neutrophil infiltration.
Asunto(s)
Erupciones por Medicamentos/inmunología , Interleucina-23/biosíntesis , Queratinocitos/inmunología , Otitis Externa/inmunología , Psoriasis/inmunología , Receptores de Interleucina-1/deficiencia , Transducción de Señal/genética , Administración Cutánea , Animales , Erupciones por Medicamentos/etiología , Erupciones por Medicamentos/metabolismo , Femenino , Eliminación de Gen , Imiquimod/administración & dosificación , Imiquimod/efectos adversos , Interleucina-17/biosíntesis , Interleucinas/biosíntesis , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Infiltración Neutrófila/efectos de los fármacos , Infiltración Neutrófila/genética , Otitis Externa/inducido químicamente , Psoriasis/inducido químicamente , Receptores de Interleucina-1/genética , Transducción de Señal/inmunología , Interleucina-22RESUMEN
The IL-1 cytokine family includes eleven members, among which Il-36α, ß and γ, IL-36Ra and IL-38. The IL-36 cytokines are involved in the pathogenesis of psoriasis. IL-38 is also expressed in the skin and was previously proposed to act as an IL-36 antagonist. In this study, we thus examined expression and function of Il-38 in a mouse model of imiquimod (IMQ)-induced skin inflammation. Il-38 mRNA was detected in the epidermis and in primary mouse keratinocytes, but not in dermal fibroblasts. At the peak of IMQ-induced inflammation, skin Il-38 mRNA levels were reduced, whereas Il-36ra mRNA expression increased. The severity of IMQ-induced skin inflammation, as assessed by recording ear thickness and histological changes, was similar in Il-38 KO and WT littermate control mice, while, in contrast, Il-36ra-deficient mice displayed more severe skin pathology than their WT littermates. Il-38-deficiency had no impact on IMQ-induced expression of proinflammatory mediators in the skin in vivo, on the basal expression of various cytokines or chemokines by cultured primary keratinocytes and dermal fibroblasts in vitro, or on the response of these cells to Il-36ß. Finally, after cessation of topical IMQ application, the resolution of skin inflammation was also not altered in Il-38 KO mice. In conclusion, Il-38-deficiency did not impact the development or resolution of IMQ-induced skin inflammation. Our observations further suggest that endogenous Il-38 does not exert Il-36 inhibitory activity in this model, or in cultured skin cells. A potential anti-inflammatory function of Il-38 in mouse skin thus still remains to be demonstrated.
Asunto(s)
Aminoquinolinas , Dermatitis/genética , Erupciones por Medicamentos/genética , Inflamación/inducido químicamente , Interleucina-1/genética , Interleucinas/genética , Piel/metabolismo , Animales , Células Cultivadas , Dermatitis/metabolismo , Dermatitis/patología , Modelos Animales de Enfermedad , Erupciones por Medicamentos/metabolismo , Erupciones por Medicamentos/patología , Femenino , Imiquimod , Inflamación/genética , Inflamación/patología , Interleucina-1/metabolismo , Interleucinas/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Ratones Noqueados , Índice de Severidad de la Enfermedad , Piel/patologíaRESUMEN
Interleukin (IL)-33 is a cytokine of the IL-1 family, which signals through the ST2 receptor. Previous work demonstrated that the systemic administration of recombinant IL-33 reduces the development of atherosclerosis in apolipoprotein E-deficient (ApoE(-/-)) mice by inducing a Th1-to-Th2 shift. The objective of our study was to examine the role of endogenous IL-33 and ST2 in atherosclerosis. ApoE(-/-), IL-33(-/-)ApoE(-/-), and ST2(-/-)ApoE(-/-) mice were fed with a cholesterol-rich diet for 10 weeks. Additionally, a group of ApoE(-/-) mice was injected with a neutralizing anti-ST2 or an isotype control antibody during the period of the cholesterol-rich diet. Atherosclerotic lesion development was measured by Oil Red O staining in the thoracic-abdominal aorta and the aortic sinus. There were no significant differences in the lipid-staining area of IL-33(-/-)ApoE(-/-), ST2(-/-)ApoE(-/-), or anti-ST2 antibody-treated ApoE(-/-) mice, compared to ApoE(-/-) controls. The absence of IL-33 signaling had no major and consistent impact on the Th1/Th2 cytokine responses in the supernatant of in vitro-stimulated lymph node cells. In summary, deficiency of the endogenously produced IL-33 and its receptor ST2 does not impact the development of atherosclerosis in ApoE-deficient mice.