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Insulinlike growth factor II and transforming growth factor β regulate collagen expression in human osteoblastlike cells in vitro
Author(s) -
Strong Donna D.,
Beachler Anthony L.,
Wergedal Jon E.,
Linkhart Thomas A.
Publication year - 1991
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1002/jbmr.5650060105
Subject(s) - procollagen peptidase , endocrinology , transforming growth factor , medicine , growth factor , messenger rna , in vitro , biology , chemistry , biochemistry , gene , receptor
Insulinlike growth factor II (IGF‐II) and transforming growth factor β (TGF‐β) are the most abundant polypeptide growth factors found in human bone matrix and are produced by human bone cells in vitro. IGF‐II and TGF‐β, increased total protein synthesis, collagenous protein synthesis, and the steady‐state level of type I procollagen mRNA in a time‐dependent manner in osteoblastlike cells isolated from human bone. Type III procollagen mRNA expression was low in untreated cultures and was not affected by IGF‐II or TGF‐β. TGF‐β, elevated type I procollagen mRNA rapidly, with the maximal observed change at 10 h. In contrast, procollagen mRNA levels increased more slowly in response to IGF‐II and reached a lower maximal level than with TGF‐β, but the response was sustained through 24 h. Collagenous protein synthesis in IGF‐II‐ and TGF‐β‐treated cells increased in parallel with increases in procollagen mRNA levels and was higher at 21 h for TGF‐β, and at 36 h for IGF‐II. The difference in the time course and magnitude of change in type I procollagen mRNA levels in response to IGF‐II and TGF‐β, suggests that these two growth factors work through distinct mechanisms that provide both a rapid transient response and a later sustained response in bone matrix biosynthetic activity.