TY - JOUR
T1 - Novel mode of processing and secretion of connective tissue growth factor/ecogenin (CTGF/Hcs24) in chondrocytic HCS-2/8 cells
AU - Kubota, S.
AU - Eguchi, T.
AU - Shimo, Tsuyoshi
AU - Nishida, T.
AU - Hattori, T.
AU - Kondo, S.
AU - Nakanishi, T.
AU - Takigawa, M.
N1 - Funding Information:
This work was supported in part by Grants-in-Aid for Scientific Research from the Ministry of Education, Science, Sports and Culture of Japan (S.K., M.T.); grants from the Research for the Future Programme of the Japan Society for the Promotion of Science (Biological Tissue Engineering Project, Contract Grant No. JSPS-RFTF98100201) (M.T.); the Naito Foundation (M.T.); the Nakatomi Health Science Foundation (M.T.); the Foundation for Growth Science in Japan (M.T.); and the Sumitomo Foundation (M.T.). The authors thank Dr. Kumiko Nawachi, Dr. Masahiro Asano, and Dr. Gen Yosimichi for helpful suggestions; Kazumi Oyama for technical assistance; and Yuki Nonami for secretarial assistance.
PY - 2001
Y1 - 2001
N2 - The synthesis, processing, and secretion of human connective tissue growth factor (CTGF/Hcs24) in a human chondrocytic cell line, HCS-2/8, were analyzed immunochemically. By metabolic pulse-labeling, chasing, and subsequent immunoprecipitation analyses, active synthesis of CTGF was observed not only in growing HCS-2/8 cells, but also in confluent cells. However, secretion and processing of CTGF were found to be regulated differentially, depending upon the growth status. During phases of growth, HCS-2/8 cells released CTGF molecules immediately without sequestering them within the cell layer. In contrast, after the cells reached confluence, the secretion slowed, resulting in an accumulation of CTGF in the cells or extracellular matrices (ECMs). Also, in confluent cell layers, a 10 kDa protein that was reactive to an anti-CTGF serum was observed. This CTGF-related small protein was not detected immediately after labeling, but gradually appeared within 6 h after chase, which suggests its entity as a processed subfragment of CTGF. Surprisingly, the 10 kDa protein was stable even 48 h after synthesis, and was not released by ECM digestion, suggesting an intracellular maintenance and function. Taken together, the behavior of CTGF in HCS-2/8 cells is remarkably different from that reported in fibroblasts, which may represent unique roles for CTGF in the growth and differentiation of chondrocytes.
AB - The synthesis, processing, and secretion of human connective tissue growth factor (CTGF/Hcs24) in a human chondrocytic cell line, HCS-2/8, were analyzed immunochemically. By metabolic pulse-labeling, chasing, and subsequent immunoprecipitation analyses, active synthesis of CTGF was observed not only in growing HCS-2/8 cells, but also in confluent cells. However, secretion and processing of CTGF were found to be regulated differentially, depending upon the growth status. During phases of growth, HCS-2/8 cells released CTGF molecules immediately without sequestering them within the cell layer. In contrast, after the cells reached confluence, the secretion slowed, resulting in an accumulation of CTGF in the cells or extracellular matrices (ECMs). Also, in confluent cell layers, a 10 kDa protein that was reactive to an anti-CTGF serum was observed. This CTGF-related small protein was not detected immediately after labeling, but gradually appeared within 6 h after chase, which suggests its entity as a processed subfragment of CTGF. Surprisingly, the 10 kDa protein was stable even 48 h after synthesis, and was not released by ECM digestion, suggesting an intracellular maintenance and function. Taken together, the behavior of CTGF in HCS-2/8 cells is remarkably different from that reported in fibroblasts, which may represent unique roles for CTGF in the growth and differentiation of chondrocytes.
KW - Cartilage
KW - Chondrocyte
KW - Connective tissue growth factor (CTGF)
KW - Extracellular matrix (ECM)
KW - HCS-2/8
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U2 - 10.1016/S8756-3282(01)00492-6
DO - 10.1016/S8756-3282(01)00492-6
M3 - Article
C2 - 11502477
AN - SCOPUS:0034897156
VL - 29
SP - 155
EP - 161
JO - Bone
JF - Bone
SN - 8756-3282
IS - 2
ER -