Einfluss von IL-6 klassik- und IL-6 trans-signaling auf Concanavalin A immunvermittelten Leberschaden

Interleukin-6 (IL-6) is a pleiotropic cytokine with various cellular functions including induction of acute phase proteins in the liver, stimulation of lymphocytes and control of regenerative processes including wound healing and liver regeneration.Prominent infiltration of lymphocytes into the liver is a hallmark for acute and chronic hepatitis. Liver injury induced by intravenous injection of the mitogenic plant lectin Concanavalin A (ConA) is considered as a murine model of T-cell mediated hepatitis accompanied by up-regulation of proinflammatory cytokines,occurrence of CD4+ T-cells in hepatic lesions but also by the involvement of an activation of resident hepatic NKT, Kupffer cells and neutrophils. In this study, the role of classic IL-6 signaling and IL-6 trans-signaling during ConA-mediated hepatitis was investigated using IL-6 deficient mice and mice either injected with anti-IL6 mAbs or sgp130Fc. Application of ConA induced liver injury in mice with massive hepatocyte necrosis and neutrophil infiltration. Surprisingly, IL-6 deficient mice and mice treated with an anti-IL-6 mAb but not with sgp130Fc showed reduced ConA induced liver injury. This was accompanied by a diminished increase of circulating and liver infiltrating neutrophils, by an upregulation of the hepatoprotective C-C chemokine ligand 2 (CCL2)/monocyte chemoattractant protein-1 (MCP-1), and by a downregulation of the hepatodestructive cytokine IL-4, but by unchanged levels of the neutrophil attracting chemokine KC. IL-6 has a dual role in ConA-induced hepatitis, which is hepatoprotective when IL-6 is injected before ConA administration and hepatodestructive if applicated after ConA administration. A single IL-6 injection to mice resulted in release of neutrophils to the circulation. These findings showed that abrogated classic IL-6-signaling in ConA mediated hepatitis exhibited liverprotective effects, which were at least in part caused by the failure to mount an efficient neutrophilia. 8 days after a first ConA injection, mice became tolerant against ConA restimulation. 24 h after a second ConA-challenge IL-6 deficient mice developed severe liver damage accompanied by increased CD4+ T-cell activation compared to completely protected wild-type animals. These data confirmed a dual mode of IL-6 action during ConA-induced hepatitis pointing to early harmful effects mediated by extensive neutrophilia and long term protective effects by an altered T-cell activation pattern.Interleukin-6 (IL-6) ist ein pleiotropes Cytokin mit verschiedenen zellulären Funktionen wie der Induktion von Akut-Phase Proteinen in der Leber, Stimulation von Lymphozyten und ist außerdem bei der Regulierung regenerativer Prozesse wie der Wundheilung und Leberregeneration beteiligt. Vermehrte Lymphozyteneinwanderung in die Leber ist ein Kennzeichen akuter und chronischer Hepatitis. Intravenöse Injektion des Pflanzenlektins Concanavalin A (ConA) führt zu erhöhter Ausschüttung proinflammatorischer Cytokine, vermehrtem Auftreten von CD4+ T-Zellen in entstehenden Leberlesionen, Aktivierung von NKT Zellen, Kupffer Zellen,neutrophilen Granulozyten und gilt als Mausmodell einer T-Zell vermittelten Hepatitis. In dieser Arbeit wurde unter Verwendung IL-6 defizienter Mäuse, anti-IL-6 Antikörper injizierter Mäuse und sgp130Fc injizierter Mäuse die Rolle von klassischem IL-6 signaling und IL-6 trans-signaling in der ConA vermittelten Hepatitis untersucht. Die Applikation von ConA führte zu einer Schädigung der Leber mit massiver Nekrose und Einwanderung von Neutrophilen. IL-6 defiziente und mit anti-IL-6 Antikörpern behandelte Mäuse wiesen im Gegensatz zu sgp130Fc behandelten Tieren reduzierte Leberschädigung auf. Zudem wurde ein verminderter Anstieg von Neutrophilen im Blutkreislauf und der Leber, eine Hochregulierung des hepatoprotektiven monocyte chemoattractant protein-1 (MCP-1), eine Herunterregulierung des leberschädigenden Cytokins IL-4, aber keine Veränderung des Neutrophilen anziehenden Chemokins KC gefunden. IL-6 spielt eine duale Rolle während der ConA vermittelten Hepatitis. IL-6 Injektion vor ConA Applikation schützt die Leber, während eine IL-6 Injektion nach ConA Applikation die Leber schädigt. Eine IL-6 Injektion führte zudem zu einer erhöhten Neutrophilenzahl im Blutkreislauf. Die Ergebnisse zeigten, dass unterbrochenes klassisches IL-6 signaling während ConA immunvermittelter Hepatitis leberschützende Effekte aufwies, die zumindest teilweise auf eine Störung der effizienten Freisetzung von Neutrophilen in den Kreislauf zurückzuführen ist. Mäuse bilden 8 Tage nach einer ersten ConA Injektion Toleranz gegenüber einer erneuten Stimulierung mit ConA aus. Im Vergleich zu geschützten wildtyp Mäusen entwickelten IL-6 defiziente erneut einen massiven Leberschaden der 24 Stunden nach ConARestimulation durch erhöhte Aktivierung von CD4+ T-Zellen gekennzeichnet war. Diese Resultate zeigen die duale Wirkungsweise von IL-6 während ConA induzierter Hepatitis mit anfänglich schädigenden und langfristig schützenden Effekten

Circulating Autoantibodies Recognizing Immunodominant Epitopes From Human Apolipoprotein B Associate With Cardiometabolic Risk Factors, but Not With Atherosclerotic Disease

Rationale: Atherosclerosis is a chronic inflammatory disease of large arteries that involves an autoimmune response with autoreactive T cells and auto-antibodies recognizing Apolipoprotein B (ApoB), the core protein of low-density lipoprotein (LDL). Here, we aimed to establish a clinical association between circulating human ApoB auto-antibodies with atherosclerosis and its clinical risk factors using a novel assay to detect auto-antibodies against a pool of highly immunogenic ApoB-peptides. Methods and Results: To detect polyclonal IgM- and IgG-antibodies recognizing ApoB, we developed a chemiluminescent sandwich ELISA with 30 ApoB peptides selected by an in silico assay for a high binding affinity to MHC-II, which cover more than 80% of known MHC-II variants in a Caucasian population. This pre-selection of immunogenic self-peptides accounted for the high variability of human MHC-II, which is fundamental to allow T cell dependent generation of IgG antibodies. We quantified levels of ApoB-autoantibodies in a clinical cohort of 307 patients that underwent coronary angiography. Plasma anti-ApoB IgG and IgM concentrations showed no differences across healthy individuals (n = 67), patients with coronary artery disease (n = 179), and patients with an acute coronary syndrome (n = 61). However, plasma levels of anti-ApoB IgG, which are considered pro-inflammatory, were significantly increased in patients with obesity (p = 0.044) and arterial hypertension (p < 0.0001). In addition, patients diagnosed with the metabolic syndrome showed significantly elevated Anti-ApoB IgG (p = 0.002). Even when normalized for total plasma IgG, anti-ApoB IgG remained highly upregulated in hypertensive patients (p < 0.0001). We observed no association with triglycerides, total cholesterol, VLDL, or LDL plasma levels. However, total and normalized anti-ApoB IgG levels negatively correlated with HDL. In contrast, total and normalized anti-ApoB IgM, that have been suggested as anti-inflammatory, were significantly lower in diabetic patients (p = 0.012) and in patients with the metabolic syndrome (p = 0.005). Conclusion: Using a novel ELISA method to detect auto-antibodies against ApoB in humans, we show that anti-ApoB IgG associate with cardiovascular risk factors but not with the clinical appearance of atherosclerosis, suggesting that humoral immune responses against ApoB are shaped by cardiovascular risk factors but not disease status itself. This novel tool will be helpful to develop immune-based risk stratification for clinical atherosclerosis in the future.Fil: Marchini, Timoteo Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Albert Ludwigs University of Freiburg; AlemaniaFil: Malchow, Sara. Albert Ludwigs University of Freiburg; AlemaniaFil: Caceres, Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Albert Ludwigs University of Freiburg; AlemaniaFil: El Rabih, Abed Al Hadi. Albert Ludwigs University of Freiburg; AlemaniaFil: Hansen, Sophie. Albert Ludwigs University of Freiburg; AlemaniaFil: Mwinyella, Timothy. Albert Ludwigs University of Freiburg; AlemaniaFil: Spiga, Lisa. Albert Ludwigs University of Freiburg; AlemaniaFil: Piepenburg, Sven. Albert Ludwigs University of Freiburg; AlemaniaFil: Horstmann, Hauke. Albert Ludwigs University of Freiburg; AlemaniaFil: Olawale, Tijani. Albert Ludwigs University of Freiburg; AlemaniaFil: Li, Xiaowei. Albert Ludwigs University of Freiburg; AlemaniaFil: Mitre, Lucia Sol. Albert Ludwigs University of Freiburg; AlemaniaFil: Gissler, Mark Colin. Albert Ludwigs University of Freiburg; AlemaniaFil: Bugger, Heiko. University of Graz; AustriaFil: Zirlik, Andreas. University of Graz; AustriaFil: Heidt, Timo. Albert Ludwigs University of Freiburg; AlemaniaFil: Hilgendorf, Ingo. Albert Ludwigs University of Freiburg; AlemaniaFil: Stachon, Peter. Albert Ludwigs University of Freiburg; AlemaniaFil: von zur Muehlen, Constantin. Albert Ludwigs University of Freiburg; AlemaniaFil: Bode, Christoph. Albert Ludwigs University of Freiburg; AlemaniaFil: Wolf, Dennis. Albert Ludwigs University of Freiburg; Alemani

The multimodal Munich Clinical Deep Phenotyping study to bridge the translational gap in severe mental illness treatment research

Introduction: Treatment of severe mental illness (SMI) symptoms, especially negative symptoms and cognitive dysfunction in schizophrenia, remains a major unmet need. There is good evidence that SMIs have a strong genetic background and are characterized by multiple biological alterations, including disturbed brain circuits and connectivity, dysregulated neuronal excitation-inhibition, disturbed dopaminergic and glutamatergic pathways, and partially dysregulated inflammatory processes. The ways in which the dysregulated signaling pathways are interconnected remains largely unknown, in part because well-characterized clinical studies on comprehensive biomaterial are lacking. Furthermore, the development of drugs to treat SMIs such as schizophrenia is limited by the use of operationalized symptom-based clusters for diagnosis. Methods: In line with the Research Domain Criteria initiative, the Clinical Deep Phenotyping (CDP) study is using a multimodal approach to reveal the neurobiological underpinnings of clinically relevant schizophrenia subgroups by performing broad transdiagnostic clinical characterization with standardized neurocognitive assessments, multimodal neuroimaging, electrophysiological assessments, retinal investigations, and omics-based analyzes of blood and cerebrospinal fluid. Moreover, to bridge the translational gap in biological psychiatry the study includes in vitro investigations on human-induced pluripotent stem cells, which are available from a subset of participants. Results: Here, we report on the feasibility of this multimodal approach, which has been successfully initiated in the first participants in the CDP cohort; to date, the cohort comprises over 194 individuals with SMI and 187 age and gender matched healthy controls. In addition, we describe the applied research modalities and study objectives. Discussion: The identification of cross-diagnostic and diagnosis-specific biotype-informed subgroups of patients and the translational dissection of those subgroups may help to pave the way toward precision medicine with artificial intelligence-supported tailored interventions and treatment. This aim is particularly important in psychiatry, a field where innovation is urgently needed because specific symptom domains, such as negative symptoms and cognitive dysfunction, and treatment-resistant symptoms in general are still difficult to treat

Role of IL-6 trans-signaling in CCl4 induced liver damage

AbstractInterleukin-6 (IL-6) plays an important role in liver regeneration and protection against liver damage. In addition to IL-6 classic signaling via membrane bound receptor (mIL-6R), IL-6 signaling can also be mediated by soluble IL-6R (sIL-6R) thereby activating cells that do not express membrane bound IL-6R. This process has been named trans-signaling. IL-6 trans-signaling has been demonstrated to operate during liver regeneration. We have developed methods to specifically block or mimic IL-6 trans-signaling. A soluble gp130 protein (sgp130Fc) exclusively inhibits IL-6 trans-signaling whereas an IL-6/sIL-6R fusion protein (Hyper-IL-6) mimics IL-6 trans-signaling. Using these tools we investigate the role of IL-6 trans-signaling in CCl4 induced liver damage. Blockade of IL-6 trans-signaling during CCl4 induced liver damage led to higher liver damage, although induction of Cyp4502E1 and thus bioactivation of CCl4 was unchanged. Depletion of neutrophils resulted in reduced liver transaminase levels irrespective of IL-6 trans-signaling blockade. Furthermore, IL-6 trans-signaling was important for refilling of hepatocyte glycogen stores, which were depleted 24h after CCl4 treatment. We conclude that IL-6 trans-signaling via the soluble IL-6R is important for the physiologic response of the liver to CCl4 induced chemical damage