α-MSH modulates cell adhesion and inflammatory responses of synovial fibroblasts from osteoarthritis patients

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• 作者：Markus Bö ; hm^a ; ^{bohmm@uni-muenster.de" class="auth_mail" title="E-mail the corresponding author} ; Mara Apel^a ; ^{wachsmut@uni-muenster.de" class="auth_mail" title="E-mail the corresponding author} ; Torsten Lowin^b ; ^{torsten.lowin@googlemail.com" class="auth_mail" title="E-mail the corresponding author} ; Julia Lorenz^c ; ^d ; ^{Julia2.Lorenz@klinik.uni-regensburg.de" class="auth_mail" title="E-mail the corresponding author} ; Zsuzsa Jenei-Lanzl^b ; ^{zsuzsa.jenei-lanzl@ukr.de" class="auth_mail" title="E-mail the corresponding author} ; Silvia Capellino^b ; ^{s.capellino@kerckhoff-klinik.de" class="auth_mail" title="E-mail the corresponding author} ; Heba Dosoki^a ; ^{hebasalah40@gmail.com" class="auth_mail" title="E-mail the corresponding author} ; Thomas A. Luger^a ; ^{Thomas.Luger@ukmuenster.de" class="auth_mail" title="E-mail the corresponding author} ; Rainer H. Straub^b ; ^{rainer.straub@klinik.uni-regensburg.de" class="auth_mail" title="E-mail the corresponding author} ; Susanne Grä ; ssel^c ; ^d ; ^{Susanne.Graessel@klinik.uni-regensburg.de" class="auth_mail" title="E-mail the corresponding author}
• 关键词：ACTH ; adrenocorticotropin ; ASIP ; Agouti signalling protein ; ATP ; adenosine triphosphate ; BSA ; bovine serum albumin ; cAMP ; 3&prime ; 5&prime ; -cyclic adenosine monophosphate ; ELISA ; enzyme-linked immunosorbent assay ; ERK ; extracellular signal-regulated protein kinase ; IL ; interleukin ; DAPI ; 4 ; 6-diamino-2-phenylindole ; FCS ; foetal calf serum ; FSK ; forskolin ; IF ; immunofluorescence ; MC ; melanocortin receptor ; MSH ; melanocyte-stimulating hormone ; OA ; osteoarthritis ; OASFs ; synovial fibroblasts from O
• 刊名：Biochemical Pharmacology
• 出版年：2016
• 出版时间：15 September 2016
• 年：2016
• 卷：116
• 期：Complete
• 页码：89-99
• 全文大小：1621 K

文摘

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 Ca²⁺ 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.