Daniel Zickler1, Christian Luecht1,2, Kevin Willy1, Lei Chen1, Janusz Witowski3, Matthias Girndt4, Roman Fiedler4, Markus Storr5, Julian Kamhieh-Milz6, Janosch Schoon7,8, Sven Geissler7,8, Olle Ringdén9, Ralf Schindler1, Guido Moll7,8,9, Duska Dragun1,2, Rusan Catar1,2. 1. Clinic for Nephrology and Critical Care Medicine, Charite-Universitatsmedizin Berlin, corporate member of Freie Universitat Berlin, Humboldt-Universitat zu Berlin, and Berlin Institute of Health (BIH), Berlin, Germany. 2. Berlin Institute of Health (BIH), Berlin, Germany. 3. Department of Pathophysiology, Poznan University of Medical Sciences, Poznan, Poland. 4. Department of Internal Medicine II, Martin-Luther-University Halle, Germany. 5. Department of Research and Development, Gambro Dialysatoren GmbH, Hechingen, Germany. 6. Department of Transfusion Medicine. 7. Berlin-Brandenburg Center and School for Regenerative Therapies(BCRT/BSRT). 8. Julius Wolff Institute for Biomechanics and Muskuloskeletal Regeneration (JWI), Charité-Universitätsmedizin Berlin, Berlin, Germany. 9. Division of Therapeutic Immunology (TIM), Department of Laboratory Medicine (LABMED), Karolinska Institutet, Stockholm, Sweden.
Abstract
Background: Vascular calcification is enhanced in uraemic chronic haemodialysis patients, likely due to the accumulation of midsize uraemic toxins, such as interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Here we have assessed the impact of uraemia on vascular smooth muscle cell (VSMC) calcification and examined the role of IL-6 and TNF-α as possible mediators and, most importantly, its underlying signalling pathway in VSMCs. Methods: VSMCs were incubated with samples of uraemic serum obtained from patients treated with haemodialysis for renal failure in the Permeability Enhancement to Reduce Chronic Inflammation-I clinical trial. The VSMCs were assessed for IL-6 gene regulation and promoter activation in response to uraemic serum and TNF-α with reporter assays and electrophoretic mobility shift assay and for osteoblastic transition, cellular calcification and cell viability upon osteogenic differentiation. Results: Uraemic serum contained higher levels of TNF-α and IL-6 compared with serum from healthy individuals. Exposure of VSMCs to uraemic serum or recombinant TNF-α lead to a strong upregulation of IL-6 mRNA expression and protein secretion, which was mediated by activator protein 1 (AP-1)/c-FOS-pathway signalling. Uraemic serum induced osteoblastic transition and calcification of VSMCs could be strongly attenuated by blocking TNF-α, IL-6 or AP-1/c-FOS signalling, which was accompanied by improved cell viability. Conclusion: These results demonstrate that uraemic serum contains higher levels of uraemic toxins TNF-α and IL-6 and that uraemia promotes vascular calcification through a signalling pathway involving TNF-α, IL-6 and the AP-1/c-FOS cytokine-signalling axis. Thus treatment modalities aiming to reduce systemic TNF-α and IL-6 levels in chronic haemodialysis patients should be evaluated in future clinical trials.
Background: Vascular calcification is enhanced in uraemic chronic haemodialysispatients, likely due to the accumulation of midsize uraemic toxins, such as interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-α). Here we have assessed the impact of uraemia on vascular smooth muscle cell (VSMC) calcification and examined the role of IL-6 and TNF-α as possible mediators and, most importantly, its underlying signalling pathway in VSMCs. Methods:VSMCs were incubated with samples of uraemic serum obtained from patients treated with haemodialysis for renal failure in the Permeability Enhancement to Reduce Chronic Inflammation-I clinical trial. The VSMCs were assessed for IL-6 gene regulation and promoter activation in response to uraemic serum and TNF-α with reporter assays and electrophoretic mobility shift assay and for osteoblastic transition, cellular calcification and cell viability upon osteogenic differentiation. Results: Uraemic serum contained higher levels of TNF-α and IL-6 compared with serum from healthy individuals. Exposure of VSMCs to uraemic serum or recombinant TNF-α lead to a strong upregulation of IL-6 mRNA expression and protein secretion, which was mediated by activator protein 1 (AP-1)/c-FOS-pathway signalling. Uraemic serum induced osteoblastic transition and calcification of VSMCs could be strongly attenuated by blocking TNF-α, IL-6 or AP-1/c-FOS signalling, which was accompanied by improved cell viability. Conclusion: These results demonstrate that uraemic serum contains higher levels of uraemic toxins TNF-α and IL-6 and that uraemia promotes vascular calcification through a signalling pathway involving TNF-α, IL-6 and the AP-1/c-FOS cytokine-signalling axis. Thus treatment modalities aiming to reduce systemic TNF-α and IL-6 levels in chronic haemodialysis patients should be evaluated in future clinical trials.
Authors: Yun Kyung Jeon; Myung Jun Shin; Sunil Kumar Saini; Carlo Custodero; Monica Aggarwal; Stephen D Anton; Christiaan Leeuwenburgh; Robert T Mankowski Journal: Exp Gerontol Date: 2020-12-26 Impact factor: 4.032
Authors: Daria Shishkova; Elena Velikanova; Maxim Sinitsky; Anna Tsepokina; Olga Gruzdeva; Leo Bogdanov; Anton Kutikhin Journal: Int J Mol Sci Date: 2019-11-15 Impact factor: 5.923