Role of Fibroblast Activation Protein Alpha in Fibroblast-like Synoviocytes of Rheumatoid Arthritis

Mohammad Javad  Mousavi; Elham  Farhadi; Mohammad  Vodjgani; Jafar  Karami; Mohammad Naghi  Tahmasebi; Arash  Sharafat Vaziri; Marzieh  Asgari; Nima  Rezaei; Shayan  Mostafaei; Ahmadreza  Jamshidi; Mahdi  Mahmoudi

doi:10.18502/ijaai.v20i3.6335

Mohammad Javad Mousavi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Elham Farhadi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Vodjgani Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Jafar Karami Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Mohammad Naghi Tahmasebi Department of Orthopedics, Division of Knee Surgery, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
Arash Sharafat Vaziri Department of Orthopedics, Division of Knee Surgery, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
Marzieh Asgari Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Nima Rezaei Department of Immunology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Shayan Mostafaei Department of Biostatistics, Faculty of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran
Ahmadreza Jamshidi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran
Mahdi Mahmoudi Rheumatology Research Center, Tehran University of Medical Sciences, Tehran, Iran

DOI: https://doi.org/10.18502/ijaai.v20i3.6335

Keywords: Fibroblast activation protein alpha; Rheumatoid arthritis; Fibroblast-like synoviocytes

Abstract

Fibroblast-like synoviocytes (FLSs) have been introduced in recent years as a key player in the pathogenesis of rheumatoid arthritis (RA), but the exact mechanisms of their transformation and intracellular pathways have not yet been determined. This study aimed to investigate the role of fibroblast activation protein-alpha (FAP-α) in the regulation of genes involved in the transformation and pathogenic activity of RA FLSs. Synovial FLSs were isolated from RA patients and non-arthritic individuals (n=10 in both groups) and characterized; using immunocytochemistry and flow cytometry analysis. FLSs were divided into un-treated and Talabostat-treated groups to evaluate the FAP-α effect on the selected genes involved in cell cycle regulation (p21, p53, CCND1), apoptosis (Bcl-2, PUMA), and inflammatory and destructive behavior of FLSs (IL-6, TGF-β1, MMP-2, MMP-9, P2RX7). Gene expression analysis was performed by quantitative real-time polymerase chain reaction (qRTPCR), and immunoblotting was carried out to evaluate FAP-α protein levels. The basal level of FAP-α protein in RA patients was significantly higher than non-arthritic control individuals. However, no differences were observed between RA and non-arthritic FLSs, at the baseline mRNA levels of all the genes. Talabostat treatment significantly reduced FAPα protein levels in both RA and non-arthritic FLSs, however, had no effect on mRNA expressions except an upregulated TGF-β1 expression in non-arthritic FLSs. A significantly higher protein level of FAP-α in FLSs of RA patients compared with that of healthy individuals may point to the pathogenic role of this protein in RA FLSs. However, more investigations are necessary to address the mechanisms mediating the FAP-α pathogenic role in RA FLSs.