Comparable response of ccn1 with ccn2 genes upon arthritis: An in vitro evaluation with a human chondrocytic cell line stimulated by a set of cytokines

Norifumi H Moritani,Masaharu Takigawa,Satoshi Kubota,Toshio Sugahara

doi:10.1186/1478-811x-3-6

Abstract

BackgroundThe chondrosarcoma-derived HCS-2/8 has been known to be an excellent model of human articular chondrocytes. By mimicking the arthritic conditions through the treatment of HCS-2/8 cells with cytokines, we estimated the gene expression response of ccn1 and ccn2 during the course of joint inflammation in vitro.ResultsIn order to mimic the initiation of inflammation, HCS-2/8 cells were treated with tumor necrosis factor (TNF)-α. To induce pro-inflammatory or reparative responses, TGF-β was employed. Effects of an anti-inflammatory glucocorticoid were also evaluated. After stimulation, expression levels of ccn1 and ccn2 were quantitatively analyzed. Surprisingly, not only ccn2, but also ccn1 expression was repressed upon TNF-α stimulation, whereas both mRNAs were uniformly induced by transforming growth factor (TGF)-β and a glucocorticoid.ConclusionThese results describing the same response during the course of inflammation suggest similar and co-operative roles of these 2 ccn family members in the course of arthritis.

Highlights

The chondrosarcoma-derived HCS-2/8 has been known to be an excellent model of human articular chondrocytes
In our present study, we assessed the gene regulation profile of CCN1 as well as CCN2 in a human chondrocytic cell line, HCS-2/8, upon the stimulation mimicking the course of chronic inflammation. This particular cell line was selected, since HCS-2/8 was established from a chondrosarcoma and has best retained a variety of mature chondrocytic phenotypes [16,17,18]. Using this in vitro model, we found CCN1 may be involved in the inflammatory response in joints and may be useful in cartilage regenerative therapeutics, as described in CCN2
Strict and discriminating quantification of ccn1 and ccn2 mRNAs by real-time-reverse transcription (RT)-PCR Since ccn1 and ccn2 are members of the same gene family, it is critically important to examine the specificity of each quantification system in order to avoid possible cross-recognition [4]

Summary

Introduction

The chondrosarcoma-derived HCS-2/8 has been known to be an excellent model of human articular chondrocytes. Osteoarthritis (OA) and rheumatoid arthritis (RA) are most common orthopaedic complexities among aged individuals [1]. They may be etiologically distinct each other, both are characterized by progressive destruction of articular cartilage, which is mainly caused by inflammatory stresses [1]. The most major problem in the therapeutics of these joint diseases is the difficulty in regenerating damaged articular cartilage. We for the first time clarified that CCN2/connective tissue growth factor (CTGF) was capable of regenerating full-thickness defect in articular cartilage and promoted the repair of damaged cartilage in an OA model in vivo [2]. Expression of ccn in OA cases (page number not for citation purposes)

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