Rsk2 controls synovial fibroblast hyperplasia and the course of arthritis

TY - JOUR

T1 - Rsk2 controls synovial fibroblast hyperplasia and the course of arthritis

AU - Derer, Anja

AU - Böhm, Christina

AU - Grötsch, Bettina

AU - Grün, Joachim R

AU - Grützkau, Andreas

AU - Stock, Michael

AU - Böhm, Sybille

AU - Sehnert, Bettina

AU - Gaipl, Udo

AU - Schett, Georg

AU - Hueber, Axel J

AU - David, Jean-Pierre

N1 - Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

PY - 2016/1/1

Y1 - 2016/1/1

N2 - OBJECTIVE: Arthritis is a chronic inflammatory disease characterised by immune cell infiltration and mesenchymal cell expansion in the joints. Although the role of immune cells in arthritis is well characterised, the development of mesenchymal cell hyperplasia needs to be better defined. Here, we analysed the role of the ribosomal S6 kinase Rsk2, which we found to be highly activated in joints of patients with arthritis, in the development of mesenchymal cell hyperplasia.METHODS: We genetically inactivated Rsk2 in the tumour necrosis factor (TNF)-α transgenic (TNFtg) mice, an animal model for human inflammatory arthritis. Clinical and histological signs of arthritis as well as molecular markers of inflammation and joint destruction were quantified. Fibroblast-like synoviocytes (FLS) were characterised in vitro and the effect of Rsk2 deletion on the pattern of gene expression was determined.RESULTS: Rsk2 deficiency in TNFtg mice results in earlier and exacerbated inflammation as well as increased bone and cartilage destruction. The production of inflammatory cytokines, matrix metalloproteinases and osteoclastogenic molecules was significantly increased in vivo upon Rsk2 inactivation. Bone marrow deficient in Rsk2 could not transfer this phenotype, indicating that Rsk2 expression in mesenchymal cells controls the course of arthritis. Indeed, Rsk2 deficiency was associated with a more activated phenotype and higher proliferative capacity of FLS, thereby increasing cytokines and production of matrix proteinases.CONCLUSIONS: Rsk2 emerges as a key regulator of mesenchymal cell numbers in the joint and thereby could be targeted to control the inflammatory and tissue-destructive feature of joints in arthritis.

AB - OBJECTIVE: Arthritis is a chronic inflammatory disease characterised by immune cell infiltration and mesenchymal cell expansion in the joints. Although the role of immune cells in arthritis is well characterised, the development of mesenchymal cell hyperplasia needs to be better defined. Here, we analysed the role of the ribosomal S6 kinase Rsk2, which we found to be highly activated in joints of patients with arthritis, in the development of mesenchymal cell hyperplasia.METHODS: We genetically inactivated Rsk2 in the tumour necrosis factor (TNF)-α transgenic (TNFtg) mice, an animal model for human inflammatory arthritis. Clinical and histological signs of arthritis as well as molecular markers of inflammation and joint destruction were quantified. Fibroblast-like synoviocytes (FLS) were characterised in vitro and the effect of Rsk2 deletion on the pattern of gene expression was determined.RESULTS: Rsk2 deficiency in TNFtg mice results in earlier and exacerbated inflammation as well as increased bone and cartilage destruction. The production of inflammatory cytokines, matrix metalloproteinases and osteoclastogenic molecules was significantly increased in vivo upon Rsk2 inactivation. Bone marrow deficient in Rsk2 could not transfer this phenotype, indicating that Rsk2 expression in mesenchymal cells controls the course of arthritis. Indeed, Rsk2 deficiency was associated with a more activated phenotype and higher proliferative capacity of FLS, thereby increasing cytokines and production of matrix proteinases.CONCLUSIONS: Rsk2 emerges as a key regulator of mesenchymal cell numbers in the joint and thereby could be targeted to control the inflammatory and tissue-destructive feature of joints in arthritis.

U2 - 10.1136/annrheumdis-2014-205618

DO - 10.1136/annrheumdis-2014-205618

M3 - SCORING: Journal article

C2 - 25414238

VL - 75

SP - 413

EP - 421

JO - ANN RHEUM DIS

JF - ANN RHEUM DIS

SN - 0003-4967

IS - 2

ER -