ABSTRACT
BACKGROUND: COVID-19 disease severity and need for intensive care has been associated with profound immune disturbances in which interleukin 6 (IL-6) is central. IL-6 signals through two pathways: classical IL-6 signalling with C-reactive protein (CRP) as a product is pivotal in the acute immune response against pathogens while IL-6 trans-signalling is involved in prolonged inflammation. We measured biomarkers of the IL-6 classical and trans-signalling pathways in patients with moderate or severe COVID-19 in the first wave of the COVID-19 pandemic. METHOD: In a longitudinal cohort study including patients admitted to Danderyd hospital, Stockholm, Sweden, with COVID-19 (n = 112), plasma IL-6 mirroring activity in both pathways, CRP as marker of classical signalling and the soluble IL-6 receptor (sIL-6R) and soluble glycoprotein 130 (sgp130) as markers of trans-signalling were analysed at baseline. Potential differences in biomarker levels between groups of moderate and severe COVID-19 defined by care level, level of respiratory support and one-month mortality was analysed, as was correlations between biomarkers. In addition, levels 4 months after hospital admission were compared to those at baseline. RESULTS: Levels of IL-6 and CRP were increased in severe COVID-19 whereas IL-6 trans-signalling markers (sIL-6R, sgp130) did not differ between the groups. CRP correlated positively with IL-6 in all patients while correlation with IL-6 could not be demonstrated for sIL-6R and sgp130 in either group. Levels of IL-6, CRP and sIL-6R were significantly decreased after 4 months whereas sgp130 levels increased. CONCLUSION: Classical signalling is the dominating IL-6 pathway in moderate-severe COVID-19.
Subject(s)
COVID-19 , Interleukin-6 , Biomarkers , C-Reactive Protein , Cytokine Receptor gp130/metabolism , Humans , Hyperplasia , Longitudinal Studies , Pandemics , Receptors, Interleukin-6/metabolism , SARS-CoV-2 , Sweden/epidemiologyABSTRACT
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 IndexABSTRACT
Anti-proinflammatory cytokine therapies against interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1 are major advancements in treating inflammatory diseases, especially rheumatoid arthritis. Such therapies are mainly performed by injection of antibodies against cytokines or cytokine receptors. We initially found that the glycolytic inhibitor 2-deoxy-d-glucose (2-DG), a simple monosaccharide, attenuated cellular responses to IL-6 by inhibiting N-linked glycosylation of the IL-6 receptor gp130. Aglycoforms of gp130 did not bind to IL-6 or activate downstream intracellular signals that included Janus kinases. 2-DG completely inhibited dextran sodium sulfate-induced colitis, a mouse model for inflammatory bowel disease, and alleviated laminarin-induced arthritis in the SKG mouse, an experimental model for human rheumatoid arthritis. These diseases have been shown to be partially dependent on IL-6. We also found that 2-DG inhibited signals for other proinflammatory cytokines such as TNF-α, IL-1ß, and interferon -γ, and accordingly, prevented death by another inflammatory disease, lipopolysaccharide (LPS) shock. Furthermore, 2-DG prevented LPS shock, a model for a cytokine storm, and LPS-induced pulmonary inflammation, a model for acute respiratory distress syndrome of coronavirus disease 2019 (COVID-19). These results suggest that targeted therapies that inhibit cytokine receptor glycosylation are effective for treatment of various inflammatory diseases.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Deoxyglucose/pharmacology , Glycosylation/drug effects , Inflammation/prevention & control , Receptors, Cytokine/drug effects , Animals , Cells, Cultured , Cytokine Receptor gp130/antagonists & inhibitors , Cytokine Receptor gp130/metabolism , Cytokine Release Syndrome/prevention & control , Cytokines/metabolism , Inflammation/chemically induced , Janus Kinases/drug effects , Lipopolysaccharides , Mice , Mice, Inbred C57BL , Mice, Knockout , Receptors, Cytokine/immunology , Receptors, Cytokine/metabolism , Receptors, Interleukin-6/antagonists & inhibitors , Receptors, Interleukin-6/genetics , Receptors, Interleukin-6/metabolismABSTRACT
LianHuaQingWen (LHQW) improves clinical symptoms and alleviates the severity of COVID-19, but the mechanism is unclear. This study aimed to investigate the potential molecular targets and mechanisms of LHQW in treating COVID-19 using a network pharmacology-based approach and molecular docking analysis. The main active ingredients, therapeutic targets of LHQW, and the pathogenic targets of COVID-19 were screened using the TCMSP, UniProt, STRING, and GeneCards databases. According to the "Drug-Ingredients-Targets-Disease" network, Interleukin 6 (IL6) was identified as the core target, and quercetin, luteolin, and wogonin as the active ingredients of LHQW associated with IL6. The response to lipopolysaccharide was the most significant biological process identified by gene ontology enrichment analysis, and AGE-RAGE signaling pathway activation was prominent based on the interaction between LHQW and COVID-19. Protein-protein docking analysis showed that IL6 receptor (IL6R)/IL6/IL6 receptor subunit beta (IL6ST) and Spike protein were mainly bound via conventional hydrogen bonds. Furthermore, protein-small molecule docking showed that all three active ingredients could bind stably in the binding model of IL6R/IL6 and IL6ST. Our findings suggest that LHQW may inhibit the lipopolysaccharide-mediated inflammatory response and regulate the AGE-RAGE signaling pathway through IL6. In addition, the N-terminal domain of the S protein of COVID-19 has a good binding activity to IL6ST, and quercetin and wogonin in LHQW may affect IL6ST-mediated IL6 signal transduction and a large number of signaling pathways downstream to other cytokines by directly affecting protein-protein interaction. These findings suggest the potential molecular mechanism by which LHQW inhibits COVID-19 through the regulation of IL6R/IL6/IL6ST.