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1.
J Biol Chem ; : 107480, 2024 Jun 17.
Article in English | MEDLINE | ID: mdl-38897568

ABSTRACT

Phospholipase A2 receptor 1 (PLA2R1) is a 180-kDa transmembrane protein that plays a role in inflammation and cancer, and is the major autoantigen in membranous nephropathy (MN), a rare but severe autoimmune kidney disease. A soluble form of PLA2R1 has been detected in mouse and human serum. It is likely produced by proteolytic shedding of membrane-bound PLA2R1 but the mechanism is unknown. Here, we show that human PLA2R1 is cleaved by A Disintegrin And Metalloprotease 10 (ADAM10) and ADAM17 in HEK293 cells, mouse embryonic fibroblasts and human podocytes. By combining site-directed mutagenesis and sequencing, we determined the exact cleavage site within the extracellular juxtamembrane stalk of human PLA2R1. Orthologs and paralogs of PLA2R1 are also shed. By using pharmacological inhibitors and genetic approaches with RNA interference and knock-out cellular models, we identified a major role of ADAM10 in the constitutive shedding of PLA2R1, and a dual role of ADAM10 and ADAM17 in the stimulated shedding. We did not observe evidence for cleavage by ß- or γ-secretase, suggesting that PLA2R1 may not be a substrate for Regulated Intramembrane Proteolysis. PLA2R1 shedding occurs constitutively and can be triggered by the calcium ionophore ionomycin, the protein kinase C inducer PMA, cytokines and lipopolysaccharides, in vitro and in vivo. Altogether, our results show that PLA2R1 is a novel substrate for ADAM10 and ADAM17, producing a soluble form that is increased in inflammatory conditions and likely exerts various functions in physiological and pathophysiological conditions including inflammation, cancer and MN.

2.
Expert Opin Ther Targets ; 28(1-2): 57-65, 2024.
Article in English | MEDLINE | ID: mdl-38217849

ABSTRACT

INTRODUCTION: Inflammatory bowel disease (IBD) is an umbrella term that includes different chronic inflammatory diseases of the gastrointestinal tract, most commonly Crohn's disease and ulcerative colitis. IBD affects more than 6 million people worldwide and constitutes not only a debilitating disease for the patients, but also a significant factor for society due to costs for health care and reduced working capacity. Despite the introduction of biologicals for the treatment of IBD, the identification of novel targets that could lead to novel therapeutics is still needed. AREAS COVERED: In this review, we summarize current knowledge about the interleukin-6 family of cytokines as potential therapeutic targets for improving the therapy of patients with IBD. We discuss cytokines like IL-6 itself for which therapeutics such as inhibitory monoclonal antibodies have already entered the clinics, but also focus on other family members whose therapeutic potential has not been explored yet. EXPERT OPINION: The different cytokines of the IL-6 family offer multiple therapeutic targets that can potentially be used to treat patients with inflammatory bowel disease, but unwanted side effects like inhibition of epithelial regeneration have to be considered.


Subject(s)
Colitis, Ulcerative , Crohn Disease , Inflammatory Bowel Diseases , Humans , Cytokines , Interleukin-6/therapeutic use , Inflammatory Bowel Diseases/drug therapy , Colitis, Ulcerative/drug therapy
3.
FEBS J ; 291(8): 1667-1683, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37994264

ABSTRACT

Interleukin-11 (IL-11) is a member of the IL-6 family of cytokines and is an important factor for bone homeostasis. IL-11 binds to and signals via the membrane-bound IL-11 receptor (IL-11R, classic signaling) or soluble forms of the IL-11R (sIL-11R, trans-signaling). Mutations in the IL11RA gene, which encodes the IL-11R, are associated with craniosynostosis, a human condition in which one or several of the sutures close prematurely, resulting in malformation of the skull. The biological mechanisms of how mutations within the IL-11R are linked to craniosynostosis are mostly unexplored. In this study, we analyze two variants of the IL-11R described in craniosynostosis patients: p.T306_S308dup, which results in a duplication of three amino-acid residues within the membrane-proximal fibronectin type III domain, and p.E364_V368del, which results in a deletion of five amino-acid residues in the so-called stalk region adjacent to the plasma membrane. The stalk region connects the three extracellular domains to the transmembrane and intracellular region of the IL-11R and contains cleavage sites for different proteases that generate sIL-11R variants. Using a combination of bioinformatics and different biochemical, molecular, and cell biology methods, we show that the IL-11R-T306_S308dup variant does not mature correctly, is intracellularly retained, and does not reach the cell surface. In contrast, the IL-11R-E364_V368del variant is fully biologically active and processed normally by proteases, thus allowing classic and trans-signaling of IL-11. Our results provide evidence that mutations within the IL11RA gene may not be causative for craniosynostosis and suggest that other regulatory mechanism(s) are involved but remain to be identified.


Subject(s)
Craniosynostoses , Interleukin-11 , Humans , Receptors, Interleukin-11/genetics , Receptors, Interleukin-11/chemistry , Receptors, Interleukin-11/metabolism , Interleukin-11/genetics , Interleukin-11/metabolism , Signal Transduction , Craniosynostoses/genetics , Peptide Hydrolases/metabolism , Receptors, Interleukin-6/genetics , Cytokine Receptor gp130/genetics
4.
Immunology ; 171(3): 377-387, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38037265

ABSTRACT

The pleiotropic cytokine interleukin-2 (IL-2) is an integral regulator of healthy and pathological immune responses, with the most important role in regulating the homeostasis of regulatory T cells. IL-2 signalling involves three distinct receptors: The IL-2 receptor α (IL-2Rα/CD25), IL-2Rß, and IL-2Rγ/γc . While IL-2Rß and γc are essential for signal transduction, IL-2Rα regulates the affinity of the receptor complex towards IL-2. A soluble form of the IL-2Rα (sIL-2Rα) is present in the blood of healthy individuals and increased under various pathological conditions. Although it is known that the sIL-2Rα retains its ability to bind IL-2, it is not fully understood how this molecule affects IL-2 function and thus immune responses. Here, we summarize the current knowledge on the generation and function of the sIL-2Rα. We describe the molecular mechanisms leading to sIL-2Rα generation and discuss the different IL-2 modulating functions that have been attributed to the sIL-2Rα. Finally, we describe attempts to utilize the sIL-2Rα as a therapeutic tool.


Subject(s)
Interleukin Receptor Common gamma Subunit , Interleukin-2 , Humans , Interleukin-2 Receptor alpha Subunit , Receptors, Interleukin-2
5.
Sci Rep ; 13(1): 13479, 2023 08 18.
Article in English | MEDLINE | ID: mdl-37596289

ABSTRACT

Craniosynostosis is characterized by the premature fusion and ossification of one or more of the sutures of the calvaria, often resulting in abnormal features of the face and the skull. In cases in which growth of the brain supersedes available space within the skull, developmental delay or cognitive impairment can occur. A complex interplay of different cell types and multiple signaling pathways are required for correct craniofacial development. In this study, we report on two siblings with craniosynostosis and a homozygous missense pathogenic variant within the IL11RA gene (c.919 T > C; p.W307R). The patients present with craniosynostosis, exophthalmos, delayed tooth eruption, mild platybasia, and a basilar invagination. The p.W307R variant is located within the arginine-tryptophan-zipper within the D3 domain of the IL-11R, a structural element known to be important for the stability of the cytokine receptor. Expression of IL-11R-W307R in cells shows impaired maturation of the IL-11R, no transport to the cell surface and intracellular retention. Accordingly, cells stably expressing IL-11R-W307R do not respond when stimulated with IL-11, arguing for a loss-of-function mutation. In summary, the IL-11R-W307R variant, reported here for the first time to our knowledge, is most likely the causative variant underlying craniosynostosis in these patients.


Subject(s)
Craniosynostoses , Humans , Craniosynostoses/genetics , Skull , Head , Brain , Arginine
6.
Methods Mol Biol ; 2691: 207-224, 2023.
Article in English | MEDLINE | ID: mdl-37355548

ABSTRACT

Interleukin-6 (IL-6) is a cytokine synthesized by many cells in the human body. IL-6 binds to a membrane-bound receptor (IL-6R), which is only present on hepatocytes, some epithelial cells, and some leukocytes. The complex of IL-6 and IL-6R binds to the ubiquitously expressed receptor subunit gp130, which forms a homodimer and thereby initiates intracellular signaling, e.g., the JAK/STAT and MAPK pathways. Proteases can cleave the membrane-bound IL-6R from the cell surface and generate a soluble IL-6R (sIL-6R), which retains its ability to bind IL-6. The IL-6/sIL-6R complex associates with gp130 and induces signaling even on cells which do not express the IL-6R. This paradigm has been called IL-6 trans-signaling, whereas signaling via the membrane-bound IL-6R is referred to as classic signaling. We have generated several molecular tools to differentiate between both pathways and to analyze the consequences of cellular IL-6 signaling in vivo. One of these tools is soluble gp130Fc, which selectively inhibits IL-6 trans-signaling. This protein under the WHO name Olamkicept has successfully undergone phase II clinical trials in patients with autoimmune diseases. Here, in this chapter, we describe several molecular tools to differentiate between IL-6 classic and trans-signaling and to analyze the consequences of cellular IL-6 signaling in vivo.


Subject(s)
Interleukin-6 , Neoplasms , Humans , Interleukin-6/genetics , Cytokine Receptor gp130/genetics , Cytokine Receptor gp130/metabolism , Receptors, Interleukin-6/genetics , Neoplasms/genetics , Cytokines/metabolism , Inflammation/metabolism
8.
Nat Rev Immunol ; 23(10): 666-681, 2023 10.
Article in English | MEDLINE | ID: mdl-37069261

ABSTRACT

Interleukin-6 (IL-6) is a key immunomodulatory cytokine that affects the pathogenesis of diverse diseases, including autoimmune diseases, chronic inflammatory conditions and cancer. Classical IL-6 signalling involves the binding of IL-6 to the membrane-bound IL-6 receptor α-subunit (hereafter termed 'mIL-6R') and glycoprotein 130 (gp130) signal-transducing subunit. By contrast, in IL-6 trans-signalling, complexes of IL-6 and the soluble form of IL-6 receptor (sIL-6R) signal via membrane-bound gp130. A third mode of IL-6 signalling - known as cluster signalling - involves preformed complexes of membrane-bound IL-6-mIL-6R on one cell activating gp130 subunits on target cells. Antibodies and small molecules have been developed that block all three forms of IL-6 signalling, but in the past decade, IL-6 trans-signalling has emerged as the predominant pathway by which IL-6 promotes disease pathogenesis. The first selective inhibitor of IL-6 trans-signalling, sgp130, has shown therapeutic potential in various preclinical models of disease and olamkicept, a sgp130Fc variant, had promising results in phase II clinical studies for inflammatory bowel disease. Technological developments have already led to next-generation sgp130 variants with increased affinity and selectivity towards IL-6 trans-signalling, along with indirect strategies to block IL-6 trans-signalling. Here, we summarize our current understanding of the biological outcomes of IL-6-mediated signalling and the potential for targeting this pathway in the clinic.


Subject(s)
Interleukin-6 , Neoplasms , Humans , Cytokine Receptor gp130/metabolism , Receptors, Interleukin-6 , Cytokines/therapeutic use , Neoplasms/drug therapy
9.
Front Pharmacol ; 13: 758233, 2022.
Article in English | MEDLINE | ID: mdl-35754497

ABSTRACT

Inflammation is a strong driver of atherosclerotic cardiovascular disease (ASCVD). There is a large unmet need for therapies that prevent or reduce excessive inflammation while avoiding systemic immunosuppression. We showed previously that selective inhibition of pro-inflammatory interleukin-6 (IL-6) trans-signalling by the fusion protein olamkicept (sgp130Fc) prevented and reduced experimental murine atherosclerosis in low-density lipoprotein receptor-deficient (Ldlr -/-) mice on a high-fat, high-cholesterol diet independently of low-density lipoprotein (LDL) cholesterol metabolism. Therefore, we allowed compassionate use of olamkicept (600 mg intravenously biweekly for 10 weeks) in a patient with very-high-risk ASCVD. Despite optimal LDL cholesterol under maximum tolerated lipid-lowering treatment, the patient had a remaining very high risk for future cardiovascular events related to significant arterial wall inflammation with lipoprotein (a) [Lp(a)]-cholesterol as the main contributor. 18Fluorodeoxyglucose positron emission tomography/computed tomography (18FDG PET/CT) measurements were performed before and after the treatment period. Olamkicept reduced arterial wall inflammation in this patient without interfering with lipoprotein metabolism. No clinical or laboratory side effects were observed during or after treatment with olamkicept. Our findings in this patient matched the results from our mechanistic study in Ldlr -/- mice, which were extended by additional analyses on vascular inflammation. Olamkicept may be a promising option for treating ASCVD independently of LDL cholesterol metabolism. A Phase II trial of olamkicept in ASCVD is currently being prepared.

10.
Front Immunol ; 13: 891456, 2022.
Article in English | MEDLINE | ID: mdl-35634332

ABSTRACT

IL-6 is one of the major mediators of the hyper-inflammatory responses with complex biological functions as it can signal via different modes of action. IL-6 by classical signalling has anti-inflammatory and antibacterial activities, while trans-signalling mediates pro-inflammatory effects. The net biological effect of IL-6 is established by multiple factors beyond its absolute concentration. Here, we assess the relationship between IL-6 signalling variables [IL-6, soluble IL-6R (sIL-6R) and soluble gp130 (sgp130)] and outcomes in a cohort of 366 COVID-19 patients. The potential trans-signalling was evaluated by a ratio between the pro-inflammatory binary IL-6:sIL-6R complex and the inactive ternary IL-6:sIL-6R:sgp130 complex (binary/ternary complex) and the fold molar excess of sgp130 over sIL-6R (FME). Our data provide new evidence that high levels of IL-6, sIL-6R, sgp130, binary/ternary complex ratio, and low FME are independent predictors of COVID-19 severity in survivor patients (without death), and the combination of IL-6 + sIL-6R + sgp130 exhibited the most robust classification capacity. Conversely, in a subgroup of patients with a very poor prognosis, we found that high levels of IL-6 and low levels of sIL-6R, sgp130, and binary/ternary complex ratio were predictors of death. In this context, the highest predictive capacity corresponded to the combined analysis of IL-6 + FME + lymphopenia + creatinine. Herein, we present IL-6 signalling variables as a helpful tool for the early identification and stratification of patients with clear implications for treatment and clinical decision-making.


Subject(s)
COVID-19 , Interleukin-6 , Receptors, Interleukin-6 , Signal Transduction , COVID-19/diagnosis , COVID-19/immunology , Cytokine Receptor gp130/metabolism , Humans , Interleukin-6/metabolism , Receptors, Interleukin-6/metabolism , Severity of Illness Index
11.
J Biol Chem ; 298(6): 101910, 2022 06.
Article in English | MEDLINE | ID: mdl-35398356

ABSTRACT

The cytokine interleukin-2 (IL-2) plays a critical role in controlling the immune homeostasis by regulating the proliferation and differentiation of immune cells, especially T cells. IL-2 signaling is mediated via the IL-2 receptor (IL-2R) complex, which consists of the IL-2Rα (CD25), the IL-2Rß, and the IL-2Rγ. While the latter are required for signal transduction, IL-2Rα controls the ligand-binding affinity of the receptor complex. A soluble form of the IL-2Rα (sIL-2Rα) is found constitutively in human serum, though its levels are increased under various pathophysiological conditions. The sIL-2Rα originates partly from activated T cells through proteolytic cleavage, but neither the responsible proteases nor stimuli that lead to IL-2Rα cleavage are known. Here, we show that the metalloproteases ADAM10 and ADAM17 can cleave the IL-2Rα and generate a soluble ectodomain, which functions as a decoy receptor that inhibits IL-2 signaling in T cells. We demonstrate that ADAM10 is mainly responsible for constitutive shedding of the IL-2Rα, while ADAM17 is involved in IL-2Rα cleavage upon T cell activation. In vivo, we found that mice with a CD4-specific deletion of ADAM10, but not ADAM17, show reduced steady-state sIL-2Rα serum levels. We propose that the identification of proteases involved in sIL-2Rα generation will allow for manipulation of IL-2Rα cleavage, especially as constitutive and induced cleavage of IL-2Rα are executed by different proteases, and thus offer a novel opportunity to alter IL-2 function.


Subject(s)
ADAM10 Protein , Interleukin-2 Receptor alpha Subunit , Receptors, Interleukin-2 , ADAM10 Protein/genetics , ADAM10 Protein/metabolism , ADAM17 Protein/genetics , ADAM17 Protein/metabolism , Animals , Gene Deletion , Interleukin-2/genetics , Interleukin-2 Receptor alpha Subunit/metabolism , Lymphocyte Activation , Mice , Receptors, Interleukin-2/genetics
12.
FASEB J ; 36(3): e22234, 2022 03.
Article in English | MEDLINE | ID: mdl-35199397

ABSTRACT

The transmembrane protease angiotensin converting enzyme 2 (ACE2) is a protective regulator within the renin angiotensin system and additionally represents the cellular receptor for SARS-CoV. The release of soluble ACE2 (sACE2) from the cell surface is hence believed to be a crucial part of its (patho)physiological functions, as both, ACE2 protease activity and SARS-CoV binding ability, are transferred from the cell membrane to body fluids. Yet, the molecular sources of sACE2 are still not completely investigated. In this study, we show different sources and prerequisites for the release of sACE2 from the cell membrane. By using inhibitors as well as CRISPR/Cas9-derived cells, we demonstrated that, in addition to the metalloprotease ADAM17, also ADAM10 is an important novel shedding protease of ACE2. Moreover, we observed that ACE2 can also be released in extracellular vesicles. The degree of either ADAM10- or ADAM17-mediated ACE2 shedding is dependent on stimulatory conditions and on the expression level of the pro-inflammatory ADAM17 regulator iRhom2. Finally, by using structural analysis and in vitro verification, we determined for the first time that the susceptibility to ADAM10- and ADAM17-mediated shedding is mediated by the collectrin-like part of ACE2. Overall, our findings give novel insights into sACE2 release by several independent molecular mechanisms.


Subject(s)
ADAM10 Protein/metabolism , ADAM17 Protein/metabolism , Amyloid Precursor Protein Secretases/metabolism , Angiotensin-Converting Enzyme 2/metabolism , Extracellular Vesicles/metabolism , Membrane Glycoproteins/metabolism , Membrane Proteins/metabolism , Severe acute respiratory syndrome-related coronavirus/metabolism , ADAM10 Protein/genetics , ADAM17 Protein/genetics , Amyloid Precursor Protein Secretases/genetics , Angiotensin-Converting Enzyme 2/genetics , Clustered Regularly Interspaced Short Palindromic Repeats , Extracellular Vesicles/genetics , HEK293 Cells , Humans , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Membrane Glycoproteins/genetics , Membrane Proteins/genetics , Severe acute respiratory syndrome-related coronavirus/genetics , SARS-CoV-2
13.
Sci Rep ; 12(1): 1943, 2022 02 04.
Article in English | MEDLINE | ID: mdl-35121767

ABSTRACT

T helper (Th) cells provide immunity to pathogens but also contribute to detrimental immune responses during allergy and autoimmunity. Th2 cells mediate asthmatic airway inflammation and Th1 cells are involved in the pathogenesis of multiple sclerosis. T cell activation involves complex transcriptional networks and metabolic reprogramming, which enable proliferation and differentiation into Th1 and Th2 cells. The essential trace element zinc has reported immunomodulatory capacity and high zinc concentrations interfere with T cell function. However, how high doses of zinc affect T cell gene networks and metabolism remained so far elusive. Herein, we demonstrate by means of transcriptomic analysis that zinc aspartate (UNIZINK), a registered pharmaceutical infusion solution with high bioavailability, negatively regulates gene networks controlling DNA replication and the energy metabolism of murine CD3/CD28-activated CD4+ T cells. Specifically, in the presence of zinc, CD4+ T cells show impaired expression of cell cycle, glycolytic and tricarboxylic acid cycle genes, which functionally cumulates in reduced glycolysis, oxidative phosphorylation, metabolic fitness and viability. Moreover, high zinc concentrations impaired nuclear expression of the metabolic transcription factor MYC, prevented Th1 and Th2 differentiation in vitro and reduced Th1 autoimmune central nervous system (CNS) inflammation and Th2 asthmatic airway inflammation induced by house dust mites in vivo. Together, we find that higher zinc doses impair the metabolic fitness of CD4+ T cells and prevent Th1 CNS autoimmunity and Th2 allergy.


Subject(s)
Aspartic Acid/analogs & derivatives , Asthma/drug therapy , Central Nervous System/drug effects , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Energy Metabolism/drug effects , Immunomodulating Agents/pharmacology , Lung/drug effects , Lymphocyte Activation/drug effects , Pneumonia/drug therapy , Th1 Cells/drug effects , Th2 Cells/drug effects , Zinc Compounds/pharmacology , Animals , Aspartic Acid/pharmacology , Asthma/genetics , Asthma/immunology , Asthma/metabolism , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Cell Proliferation/drug effects , Cells, Cultured , Central Nervous System/immunology , Central Nervous System/metabolism , Encephalomyelitis, Autoimmune, Experimental/genetics , Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/metabolism , Energy Metabolism/genetics , Gene Expression Regulation , Lung/immunology , Lung/metabolism , Lymphocyte Activation/genetics , Mice, Inbred C57BL , Mice, Transgenic , Pneumonia/genetics , Pneumonia/immunology , Pneumonia/metabolism , Pyroglyphidae/immunology , Signal Transduction , Th1 Cells/immunology , Th1 Cells/metabolism , Th2 Cells/immunology , Th2 Cells/metabolism , Transcription, Genetic
14.
Biochim Biophys Acta Mol Cell Res ; 1869(1): 119135, 2022 01.
Article in English | MEDLINE | ID: mdl-34624437

ABSTRACT

Although interleukin-11 (IL-11) was discovered more than 30 years ago, it remains an understudied member of the IL-6 family of cytokines. While it was originally discovered as a secreted factor that could foster megakaryocyte maturation and was therefore used as a recombinant protein to increase platelet production in patients with thrombocytopenia, recent research has established important roles for IL-11 in inflammation, fibrosis and cancer. In order to initiate signal transduction, IL-11 binds first to a non-signaling membrane-bound IL-11 receptor (IL-11R, classic signaling), which subsequently induces the formation of a heterodimer of the signal-transducing receptor gp130 that is shared with the other family members. Complex formation initiates several intracellular signaling cascades, most notably the Janus kinase/Signal Transducer and Activator of Transcription (Jak/STAT) pathway. We have recently identified a trans-signaling mechanism, in which IL-11 binds to soluble forms of the IL-11R (sIL-11R) and the agonistic IL-11/sIL-11R complex can activate cells that do not express the IL-11R and would usually not respond to IL-11. The generation of sIL-11R and thus the initiation of IL-11 trans-signaling is mediated by proteolytic cleavage. In this review, we summarize the current state of knowledge regarding IL-11R cleavage, highlight recent developments in IL-11 biology and discuss therapeutic opportunities and challenges in the light of IL-11 classic and trans-signaling.


Subject(s)
Interleukin-11/metabolism , Proteolysis , Animals , Humans , Receptors, Interleukin-11/metabolism , Signal Transduction
15.
Biochim Biophys Acta Mol Cell Res ; 1869(1): 119143, 2022 01.
Article in English | MEDLINE | ID: mdl-34626681

ABSTRACT

The pleiotropic cytokine interleukin-6 (IL-6) is involved in numerous physiological and pathophysiological functions that include development, immune cell differentiation, inflammation and cancer. IL-6 can signal via the membrane-bound IL-6 receptor (IL-6R, classic signaling) or via soluble forms of the IL-6R (sIL-6R, trans-signaling). Both modes of signaling induce the formation of a homodimer of the signal transducing ß-receptor glycoprotein 130 (gp130) and the activation of several intracellular signaling cascades, e.g. the Jak/STAT pathway. Intriguingly, only IL-6 trans-signaling is required for the pro-inflammatory properties of IL-6, while regenerative and anti-inflammatory functions are mediated via classic signaling. The sIL-6R is generated by different molecular mechanisms, including alternative mRNA splicing, proteolysis of the membrane-bound IL-6R and the release of extracellular vesicles. In this review, we give an in-depth overview on these molecular mechanisms with a special emphasize on IL-6R cleavage by the metalloprotease ADAM17 and other proteases. We discuss the biological functions of the sIL-6R and highlight attempts to selectively block IL-6 trans-signaling in pre-clinical animal models as well as in clinical studies in patients with inflammatory bowel disease.


Subject(s)
Inflammatory Bowel Diseases/drug therapy , Proteolysis , Receptors, Interleukin-6/metabolism , Animals , Anti-Inflammatory Agents/pharmacology , Humans , Interleukin-6/metabolism , Receptors, Interleukin-6/genetics , Recombinant Fusion Proteins/pharmacology , Signal Transduction/drug effects
16.
Blood Adv ; 6(2): 399-404, 2022 01 25.
Article in English | MEDLINE | ID: mdl-34559181

ABSTRACT

Somatic mutations in JAK2, MPL and Calreticulin and inflammation play a key role in pathophysiology of chronic myeloproliferative neoplasia (CMN). One of the most prominent cytokines elevated in serum of Polycythemia vera patients is interleukin-6 (IL-6). Currently, it is being discussed whether suppression of inflammation by anti-cytokine approaches as anti-IL-6 treatment may be therapeutically useful in CMN. We here sought to investigate the efficacy of anti-IL-6 treatment on inflammatory cytokines, hematocrit and splenomegaly in CMN like disease. JAK2-V617F knock-in mice (JAK2+/V617F) were treated for three weeks with anti-IL-6 antibody (Ab) or IgG-control. Upon anti-IL-6 Ab treatment, serum levels of CXCL2 and CXCL10 were significantly reduced. In addition, CXCL1, CCL11, M-CSF, G-CSF, IL-17, IL-12p40 and CCL2 were reduced by a factor of 0.3 -- 0.8. Partly, this was also achieved by applying high-dose IgG. Hematocrit, erythrocyte and leukocyte counts were elevated in JAK2+/V617F mice but were not reduced by anti-IL6 Ab treatment. In addition, there was no apparent amelioration of splenomegaly and spleen histopathology. In conclusion, anti-IL-6 Ab treatment did not result in improvement of hematological disease parameters but was shown to modulate the serum cytokine signature.


Subject(s)
Myeloproliferative Disorders , Polycythemia Vera , Animals , Cytokines , Disease Models, Animal , Hematocrit , Humans , Immunoglobulin G/therapeutic use , Inflammation , Interleukin-6 , Mice , Myeloproliferative Disorders/drug therapy , Polycythemia Vera/complications , Polycythemia Vera/drug therapy , Polycythemia Vera/genetics , Splenomegaly/drug therapy , Splenomegaly/etiology
17.
FEBS Lett ; 595(24): 3072-3082, 2021 12.
Article in English | MEDLINE | ID: mdl-34778975

ABSTRACT

Interleukin-6 (IL-6) and interleukin-11 (IL-11) are two important pleiotropic cytokines, both of which signal through a homodimer of the ß-receptor gp130. Specificity is gained through the unique, nonsignaling α-receptors IL-6R and IL-11R. Soluble variants of IL-6R and IL-11R also exist. Both membrane-bound receptors can be cleaved by the metalloprotease ADAM10. Here, we use ten different chimeric receptors consisting of different parts of IL-6R and IL-11R and analyze their susceptibility toward cleavage by ADAM10. As expected, all chimeras are substrates of ADAM10. However, we observed that cleavage of chimeric receptors containing the stalk region of the IL-11R could be blocked by the protease inhibitor GI (selective for ADAM10), but not by the protease inhibitor GW (selective for both ADAM10 and ADAM17), suggesting that another protease besides ADAM10 is involved in cleavage of these chimeras.


Subject(s)
ADAM10 Protein/metabolism , Ionomycin/pharmacology , Proteolysis , Receptors, Interleukin-11/metabolism , Recombinant Fusion Proteins/pharmacology , HEK293 Cells , Humans , Interleukin-6/chemistry , Interleukin-6/metabolism , Protease Inhibitors/pharmacology , Proteolysis/drug effects , Receptors, Interleukin-11/chemistry
18.
iScience ; 24(11): 103309, 2021 Nov 19.
Article in English | MEDLINE | ID: mdl-34765926

ABSTRACT

Blocking the activity of cytokines is an efficient strategy to combat inflammatory diseases. Interleukin-6 (IL-6) fulfills its pro-inflammatory properties via its soluble receptor (IL-6 trans-signaling). The selective trans-signaling inhibitor olamkicept (sgp130Fc) is currently in clinical development. We have previously shown that sgp130Fc can also efficiently block trans-signaling of the closely related cytokine IL-11, which elicits the question how selectivity for one of the two cytokines can be achieved. Using structural information, we show that the interfaces between IL-6R-gp130 and IL-11R-gp130, respectively, within the so-called site III are different between the two cytokines. Modification of an aromatic cluster around Q113 of gp130 within these interfaces allows the discrimination between IL-6 and IL-11 trans-signaling. Using recombinant sgp130Fc variants, we demonstrate that these differences can indeed be exploited to generate a truly selective IL-6 trans-signaling inhibitor. Our data highlight how the selectivity of a clinically relevant designer protein can be further improved.

19.
Best Pract Res Clin Rheumatol ; 35(4): 101722, 2021 12.
Article in English | MEDLINE | ID: mdl-34732285

ABSTRACT

Osteoarthritis (OA) is a degenerative joint disease characterized by progressive degeneration of articular cartilage. Due to its high prevalence and limited treatment options, OA has become one of the most disabling diseases in developed countries. In recent years, OA has been recognized as a heterogenic disease with various phenotypes. Calcium crystal-related endotypes, which are defined by either a distinct functional or pathobiological mechanism, are present in approximately 60% of all OA patients. Two different calcium crystals can accumulate in the joint and thereby calcify the cartilage matrix, which are basic calcium phosphate (BCP) and calcium pyrophosphate (CPP) crystals. The formation of these crystals depends mainly on the balance of phosphate and pyrophosphate, which is regulated by specific proteins controlling the pyrophosphate metabolism. Dysregulation of these molecules subsequently leads to preferential formation of either BCP or CPP crystals. BCP crystals, on the one hand, are directly associated with OA severity and cartilage degradation. They are mostly located in the deeper cartilage layers and are associated with chondrocyte hypertrophy. CPP crystal deposition, on the other hand, is a hallmark of chondrocalcinosis and is associated with aging and chondrocyte senescence. Therefore, BCP and CPP crystals are associated with different chondrocyte phenotypes. However, BCP and CPP crystals are not mutually exclusive and can coexist in OA, creating a mixed endotype of OA. Both crystals clearly play a role in the pathogenesis of OA. However, the exact impact of each crystal type on either driving the disease progression or being a result of chondrocyte differentiation is still to be elucidated.


Subject(s)
Cartilage, Articular , Chondrocalcinosis , Osteoarthritis , Calcium , Calcium Pyrophosphate , Chondrocalcinosis/etiology , Chondrocytes , Humans , Osteoarthritis/etiology
20.
Nutrients ; 13(11)2021 Oct 23.
Article in English | MEDLINE | ID: mdl-34835991

ABSTRACT

Maternal obesity greatly affects next generations, elevating obesity risk in the offspring through perinatal programming and flawed maternal and newborn nutrition. The exact underlying mechanisms are poorly understood. Interleukin-6 (IL-6) mediates its effects through a membrane-bound receptor or by trans-signaling (tS), which can be inhibited by the soluble form of the co-receptor gp130 (sgp130). As IL-6 tS mediates western-style diet (WSD) effects via chronic low-grade inflammation (LGI) and LGI is an important mediator in brain-adipose tissue communication, this study aims at determining the effects of maternal obesity in a transgenic mouse model of brain-restricted IL-6tS inhibition (GFAPsgp130) on offspring's short- and long-term body composition and epigonadal white adipose tissue (egWAT) metabolism. Female wild type (WT) or transgenic mice were fed either standard diet (SD) or WSD pregestationally, during gestation, and lactation. Male offspring received SD from postnatal day (P)21 to P56 and were metabolically challenged with WSD from P56 to P120. At P21, offspring from WT and transgenic dams that were fed WSD displayed increased body weight and egWAT mass, while glucose tolerance testing showed the strongest impairment in GFAPsgp130WSD offspring. Simultaneously, egWAT proteome reveals a characteristic egWAT expression pattern in offspring as a result of maternal conditions. IL-6tS inhibition in transgenic mice was in tendency associated with lower body weight in dams on SD and their respective offspring but blunted by the WSD. In conclusion, maternal nutrition affects offspring's body weight and egWAT metabolism predominantly independent of IL-6tS inhibition, emphasizing the importance of maternal and newborn nutrition for long-term offspring health.


Subject(s)
Brain/metabolism , Interleukin-6/metabolism , Obesity, Maternal/metabolism , Signal Transduction , Adipokines/genetics , Adipokines/metabolism , Adipose Tissue, White/metabolism , Animals , Biomarkers/blood , Body Weight , Diet , Diet, Western , Female , Glucose Tolerance Test , Insulin/metabolism , Male , Mice, Inbred C57BL , Obesity, Maternal/blood , Phenotype , Pregnancy , Proteome/metabolism , Proteomics , RNA, Messenger/genetics , RNA, Messenger/metabolism
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