Markus Böhm1, Mara Apel2, Torsten Lowin3, Julia Lorenz4, Zsuzsa Jenei-Lanzl5, Silvia Capellino6, Heba Dosoki7, Thomas A Luger8, Rainer H Straub9, Susanne Grässel10. 1. Dept. of Dermatology, Laboratory for Neuroendocrinology and Interdisciplinary Endocrinology, University of Münster, Münster, Germany. Electronic address: bohmm@uni-muenster.de. 2. Dept. of Dermatology, Laboratory for Neuroendocrinology and Interdisciplinary Endocrinology, University of Münster, Münster, Germany. Electronic address: wachsmut@uni-muenster.de. 3. Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Dept. of Internal Medicine I, University of Regensburg, Regensburg, Germany. Electronic address: torsten.lowin@googlemail.com. 4. Dept. of Orthopaedic Surgery, University of Regensburg, Regensburg, Germany; Centre for Medical Biotechnology, BioPark I, Regensburg, Germany. Electronic address: Julia2.Lorenz@klinik.uni-regensburg.de. 5. Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Dept. of Internal Medicine I, University of Regensburg, Regensburg, Germany. Electronic address: zsuzsa.jenei-lanzl@ukr.de. 6. Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Dept. of Internal Medicine I, University of Regensburg, Regensburg, Germany. Electronic address: s.capellino@kerckhoff-klinik.de. 7. Dept. of Dermatology, Laboratory for Neuroendocrinology and Interdisciplinary Endocrinology, University of Münster, Münster, Germany. Electronic address: hebasalah40@gmail.com. 8. Dept. of Dermatology, Laboratory for Neuroendocrinology and Interdisciplinary Endocrinology, University of Münster, Münster, Germany. Electronic address: Thomas.Luger@ukmuenster.de. 9. Laboratory of Experimental Rheumatology and Neuroendocrine Immunology, Dept. of Internal Medicine I, University of Regensburg, Regensburg, Germany. Electronic address: rainer.straub@klinik.uni-regensburg.de. 10. Dept. of Orthopaedic Surgery, University of Regensburg, Regensburg, Germany; Centre for Medical Biotechnology, BioPark I, Regensburg, Germany. Electronic address: Susanne.Graessel@klinik.uni-regensburg.de.
Abstract
INTRODUCTION: The synovium is a target for neuropeptides. Melanocortins have attained particular attention as they elicit antiinflammatory effects. Although synovial fluid from patients with rheumatic diseases contains α-melanocyte-stimulating hormone (α-MSH) it is unknown whether synovial fibroblasts generate α-MSH and respond to melanocortins. METHODS: Synovial tissue was obtained from osteoarthritis (OA) patients. Cells were isolated and prepared either as primary mixed synoviocytes or propagated as synovial fibroblasts (OASFs). Melanocortin receptor (MC) and proopiomelanocortin (POMC) expression were investigated by endpoint RT-PCR, immunofluorescence and Western immunoblotting. Functional coupling of MC1 was assessed by cAMP and Ca(2+) assays. Cell adhesion was monitored by the xCELLigence system. Secretion of α-MSH, tumour necrosis factor (TNF), interleukin (IL)-6 and IL-8 was determined by ELISA. RESULTS: OASFs in vitro expressed MC1. MC1 transcripts were present in synovial tissue and appropriate immunoreactivity was detected in synovial fibroblasts in situ. OASFs contained truncated POMC transcripts but neither full-length POMC mRNA, POMC protein nor α-MSH were detectable. In accordance with this only truncated POMC transcripts were present in synovial tissue. α-MSH increased cAMP dose-dependently but did not alter calcium in OASFs. α-MSH also enhanced adhesion of OASFs to fibronectin and reduced TNF, IL-6 and IL-8 secretion in primary mixed synoviocyte cultures. In OASFs, α-MSH modulated basal and TNF/IL-1β-mediated secretion of IL-6 and IL-8. CONCLUSION: Synovial fibroblasts express MC1in vitro and in situ. α-MSH elicits biological effects in these cells suggesting an endogenous immunomodulatory role of melanocortins within the synovium. Our results encourage in vivo studies with melanocortins in OA models.
INTRODUCTION: The synovium is a target for neuropeptides. Melanocortins have attained particular attention as they elicit antiinflammatory effects. Although synovial fluid from patients with rheumatic diseases contains α-melanocyte-stimulating hormone (α-MSH) it is unknown whether synovial fibroblasts generate α-MSH and respond to melanocortins. METHODS: Synovial tissue was obtained from osteoarthritis (OA) patients. Cells were isolated and prepared either as primary mixed synoviocytes or propagated as synovial fibroblasts (OASFs). Melanocortin receptor (MC) and proopiomelanocortin (POMC) expression were investigated by endpoint RT-PCR, immunofluorescence and Western immunoblotting. Functional coupling of MC1 was assessed by cAMP and Ca(2+) assays. Cell adhesion was monitored by the xCELLigence system. Secretion of α-MSH, tumour necrosis factor (TNF), interleukin (IL)-6 and IL-8 was determined by ELISA. RESULTS: OASFs in vitro expressed MC1. MC1 transcripts were present in synovial tissue and appropriate immunoreactivity was detected in synovial fibroblasts in situ. OASFs contained truncated POMC transcripts but neither full-length POMC mRNA, POMC protein nor α-MSH were detectable. In accordance with this only truncated POMC transcripts were present in synovial tissue. α-MSH increased cAMP dose-dependently but did not alter calcium in OASFs. α-MSH also enhanced adhesion of OASFs to fibronectin and reduced TNF, IL-6 and IL-8 secretion in primary mixed synoviocyte cultures. In OASFs, α-MSH modulated basal and TNF/IL-1β-mediated secretion of IL-6 and IL-8. CONCLUSION: Synovial fibroblasts express MC1in vitro and in situ. α-MSH elicits biological effects in these cells suggesting an endogenous immunomodulatory role of melanocortins within the synovium. Our results encourage in vivo studies with melanocortins in OA models.
Authors: Trinidad Montero-Melendez; Ai Nagano; Claude Chelala; Andrew Filer; Christopher D Buckley; Mauro Perretti Journal: Nat Commun Date: 2020-02-06 Impact factor: 14.919
Authors: Radomir M Slominski; Robert C Tuckey; Pulak R Manna; Anton M Jetten; Arnold Postlethwaite; Chander Raman; Andrzej T Slominski Journal: Genes Immun Date: 2020-03-23 Impact factor: 2.676