Research article

Advanced glycation end products induce cell cycle arrest and proinflammatory changes in osteoarthritic fibroblast-like synovial cells

Sybille Franke¹ , Manfred Sommer¹ , Christiane Rüster¹ , Tzvetanka Bondeva¹ , Julia Marticke² , Gunther Hofmann² , Gert Hein¹ and Gunter Wolf¹

¹  Department Internal Medicine III, Jena University Hospital, Erlanger Allee 101, Jena, 07740, Germany

²  Department of Traumatology, Hand and Reconstructive Surgery, Jena University Hospital, Erlanger Allee 101, Jena, 07740, Germany

author email corresponding author email

Arthritis Research & Therapy 2009, 11:R136doi:10.1186/ar2807

Published:	7 September 2009

Abstract

Introduction

Advanced glycation end products (AGEs) have been introduced to be involved in the pathogenesis of osteoarthritis (OA). The influence of AGEs on osteoarthritic fibroblast-like synovial cells (FLS) has been incompletely understood as yet. The present study investigates a potential influence of AGE-modified bovine serum albumin (AGE-BSA) on cell growth, and on the expression of proinflammatory and osteoclastogenic markers in cultured FLS.

Methods

FLS were established from OA joints and stimulated with AGE-BSA. The mRNA expression of p27^Kip1, RAGE (receptor for AGEs), nuclear factor kappa B subunit p65 (NFκB p65), tumor necrosis factor alpha (TNF-α, interleukin-6 (IL-6), receptor activator of NFκB ligand (RANKL) and osteoprotegerin was measured by real-time PCR. The respective protein expression was evaluated by western blot analysis or ELISA. NFκB activation was investigated by luciferase assay and electrophoretic mobility shift assay (EMSA). Cell cycle analysis, cell proliferation and markers of necrosis and early apoptosis were assessed. The specificity of the response was tested in the presence of an anti-RAGE antibody.

Results

AGE-BSA was actively taken up into the cells as determined by immunohistochemistry and western blots. AGE-induced p27^Kip1 mRNA and protein expression was associated with cell cycle arrest and an increase in necrotic, but not apoptotic cells. NFκB activation was confirmed by EMSAs including supershift experiments. Anti-RAGE antibodies attenuated all AGE-BSA induced responses. The increased expression of RAGE, IL-6 and TNF-α together with NFκB activation indicates AGE-mediated inflammation. The decreased expression of RANKL and osteoprotegerin may reflect a diminished osteoclastogenic potential.

Conclusions

The present study demonstrates that AGEs modulate growth and expression of genes involved in the pathophysiological process of OA. This may lead to functional and structural impairment of the joints.