OBJECTIVE: Since fibroblasts in the synovium of patients with rheumatoid arthritis (RA) express the serine proteases fibroblast activation protein (FAP) and dipeptidylpeptidase 4 (DPP-4)/CD26, we undertook the current study to determine the functional role of both enzymes in the invasion of RA synovial fibroblasts (RASFs) into articular cartilage. METHODS: Expression of FAP and DPP-4/CD26 by RASFs was analyzed using fluorescence-activated cell sorting and immunocytochemistry. Serine protease activity was measured by cleavage of fluorogenic substrates and inhibited upon treatment with L-glutamyl L-boroproline. The induction and expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in RASFs were detected using real-time polymerase chain reaction. Densitometric measurements of MMPs using immunoblotting confirmed our findings on the messenger RNA level. Stromal cell-derived factor 1 (SDF-1 [CXCL12]), MMP-1, and MMP-3 protein levels were measured using enzyme-linked immunosorbent assay. The impact of FAP and DPP-4/CD26 inhibition on the invasiveness of RASFs was analyzed in the SCID mouse coimplantation model of RA using immunohistochemistry. RESULTS: Inhibition of serine protease activity of FAP and DPP-4/CD26 in vitro led to increased levels of SDF-1 in concert with MMP-1 and MMP-3, which are downstream effectors of SDF-1 signaling. Using the SCID mouse coimplantation model, inhibition of enzymatic activity in vivo significantly promoted invasion of xenotransplanted RASFs into cotransplanted human cartilage. Zones of cartilage resorption were infiltrated by FAP-expressing RASFs and marked by a significantly higher accumulation of MMP-1 and MMP-3, when compared with controls. CONCLUSION: Our results indicate a central role for the serine protease activity of FAP and DPP-4/CD26 in protecting articular cartilage against invasion by synovial fibroblasts in RA.
OBJECTIVE: Since fibroblasts in the synovium of patients with rheumatoid arthritis (RA) express the serine proteases fibroblast activation protein (FAP) and dipeptidylpeptidase 4 (DPP-4)/CD26, we undertook the current study to determine the functional role of both enzymes in the invasion of RA synovial fibroblasts (RASFs) into articular cartilage. METHODS: Expression of FAP and DPP-4/CD26 by RASFs was analyzed using fluorescence-activated cell sorting and immunocytochemistry. Serine protease activity was measured by cleavage of fluorogenic substrates and inhibited upon treatment with L-glutamyl L-boroproline. The induction and expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in RASFs were detected using real-time polymerase chain reaction. Densitometric measurements of MMPs using immunoblotting confirmed our findings on the messenger RNA level. Stromal cell-derived factor 1 (SDF-1 [CXCL12]), MMP-1, and MMP-3 protein levels were measured using enzyme-linked immunosorbent assay. The impact of FAP and DPP-4/CD26 inhibition on the invasiveness of RASFs was analyzed in the SCIDmouse coimplantation model of RA using immunohistochemistry. RESULTS: Inhibition of serine protease activity of FAP and DPP-4/CD26 in vitro led to increased levels of SDF-1 in concert with MMP-1 and MMP-3, which are downstream effectors of SDF-1 signaling. Using the SCIDmouse coimplantation model, inhibition of enzymatic activity in vivo significantly promoted invasion of xenotransplanted RASFs into cotransplanted humancartilage. Zones of cartilage resorption were infiltrated by FAP-expressing RASFs and marked by a significantly higher accumulation of MMP-1 and MMP-3, when compared with controls. CONCLUSION: Our results indicate a central role for the serine protease activity of FAP and DPP-4/CD26 in protecting articular cartilage against invasion by synovial fibroblasts in RA.
Authors: Premarani Sinnathurai; Wendy Lau; Ana Julia Vieira de Ribeiro; William W Bachovchin; Helen Englert; Graydon Howe; David Spencer; Nicholas Manolios; Mark D Gorrell Journal: Int J Rheum Dis Date: 2016-12-19 Impact factor: 2.454
Authors: Yael Haberman; Phillip Minar; Rebekah Karns; Phillip J Dexheimer; Sudhir Ghandikota; Samuel Tegge; Daniel Shapiro; Brianne Shuler; Suresh Venkateswaran; Tzipi Braun; Allison Ta; Thomas D Walters; Robert N Baldassano; Joshua D Noe; Joel Rosh; James Markowitz; Jennifer L Dotson; David R Mack; Richard Kellermayer; Anne M Griffiths; Melvin B Heyman; Susan S Baker; Dedrick Moulton; Ashish S Patel; Ajay S Gulati; Steven J Steiner; Neal LeLeiko; Anthony Otley; Maria Oliva-Hemker; David Ziring; Ranjana Gokhale; Sandra Kim; Stephen L Guthery; Stanley A Cohen; Scott Snapper; Bruce J Aronow; Michael Stephens; Greg Gibson; Jonathan R Dillman; Marla Dubinsky; Jeffrey S Hyams; Subra Kugathasan; Anil G Jegga; Lee A Denson Journal: J Crohns Colitis Date: 2020-08-08 Impact factor: 9.071
Authors: Ulf Petrausch; Petra C Schuberth; Christian Hagedorn; Alex Soltermann; Sandra Tomaszek; Rolf Stahel; Walter Weder; Christoph Renner Journal: BMC Cancer Date: 2012-12-22 Impact factor: 4.430