Bosserhoff Anja-Katrin, Hofmeister Simone, Ruedel Anke, Schubert Thomas
Institute of Pathology, University of Regensburg Regensburg, Germany.
Institute of Applied Pathology Speyer, Germany.
Int J Clin Exp Pathol. 2014 Apr 15;7(5):1947-56. eCollection 2014.
In a recent study we determined a strong differential expression of DCC in OA compared to normal chondrocytes and a strong impact of the DCC receptor on cellular mobility triggered by its ligand Netrin-1. Migration of chondrocytes or their progenitor cells may play a role in remodeling of cartilage and pathological conditions. The purpose of this study is to identify subsets of chondrocytes expressing DCC and to understand signaling pathways used by DCC in chondrocytes.
Immunofluorescent histology of human cartilage was used to determine the expression pattern of CD166, DCC and p-CREB. Cell culture of chondrocytes and SW1353, transient transfection, siRNA transfection, EMSA, luciferase assay, quantitative RT-PCR, ELISA, and Western Blotting were used to study signaling down-stream of DCC.
DCC expressing chondrocytes are mainly located in the surface layers of OA cartilage. These also express CD166 indicating that DCC expressing chondrocytes are progenitor cells. Interestingly, expression of DCC reduces cAMP levels, CREB DNA-binding activity and CRE activity in chondrocytes, whereas down-regulation of DCC results in induction of CRE signaling.
In summary, DCC is up-regulated in CD166-positive chondrogenic progenitor cells in OA and induces down-regulation of CREB. These findings indicate that migration of CD166 positive progenitor cells to sites of cartilage damage may be directed by regulation of DCC signaling.
在最近的一项研究中，我们确定了与正常软骨细胞相比，DCC在骨关节炎（OA）中存在强烈的差异表达，并且DCC受体对其配体Netrin-1触发的细胞迁移有强烈影响。软骨细胞或其祖细胞的迁移可能在软骨重塑和病理状况中起作用。本研究的目的是鉴定表达DCC的软骨细胞亚群，并了解DCC在软骨细胞中使用的信号通路。
用人软骨的免疫荧光组织学来确定CD166、DCC和p-CREB的表达模式。使用软骨细胞和SW1353的细胞培养、瞬时转染、siRNA转染、电泳迁移率变动分析（EMSA）、荧光素酶测定、定量逆转录聚合酶链反应（RT-PCR）、酶联免疫吸附测定（ELISA）和蛋白质免疫印迹法来研究DCC下游的信号传导。
表达DCC的软骨细胞主要位于OA软骨的表层。这些细胞也表达CD166，表明表达DCC的软骨细胞是祖细胞。有趣的是，DCC的表达降低了软骨细胞中的环磷酸腺苷（cAMP）水平、CREB的DNA结合活性和CRE活性，而DCC的下调导致CRE信号的诱导。
总之，在OA中，CD166阳性软骨生成祖细胞中的DCC上调并诱导CREB下调。这些发现表明，CD166阳性祖细胞向软骨损伤部位的迁移可能受DCC信号调节的指导。
