Isolation and partial characterization of mitogenic factors from cementum

Abstract

Cementum is the mineralized structure through which soft connective tissues are attached to the teeth. It is a unique calcified tissue characterized by a low metabolic turnover, lack of blood supply, and presence of very few cells. However, it contains substances that influence the biological activities of fibroblasts of adjacent soft tissues. We have partially characterized cementum proteins that have mitogenic activity toward fibroblasts. Cementum was harvested from bovine teeth, and mitogenic factors were extracted in 0.5 M CH3COOH. Heparin-Sepharose chromatography separated the mitogenic activity into a major and a minor fraction eluted by 0.5 and 2.0 M NaCl, respectively. The distribution of cementum mitogens in heparin-Sepharose fractions was different from that of alveolar bone and other bones. The cementum mitogenic factor eluting with 2.0 M NaCl from a heparin-Sepharose column was shown to be basic fibroblast growth factor (bFGF) on the basis of inhibition by anti-bFGF antibody and Western blots. The 0.5 M NaCl fraction was purified by HPLC with use of a combination of a DEAE-3W column followed by TSK-250 and C18 columns. NaDodSO4-polyacrylamide gel electrophoresis revealed that the purified fraction contained two protein bands with Mr 22,000 and 19,000, and mitogenic activity was associated with the Mr 22,000 species. The activity of this mitogen, designated as CGF, was potentiated by small quantities of plasma-derived serum or epidermal growth factor. It was heat resistant, but was destroyed by reduction. Assays of CGF preparations revealed that they contained no detectable platelet-derived growth factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Attachment Activity of Cementum Proteins and Mechanism of Endotoxin Inhibition

“…To facilitate connective tissue formation and attachment, attempts have been made to supplement planed roots with molecules such as fibronectin and growth factors; however, these substances have met with only a limited and variable degree of success (Caffesse et al, 1988;Nyman et al, 1988;Wikesjo et al, 1988;Lynch et al, 1989). The cementum proteins are likely to be a more logical choice for this purpose, because they are normal constituents of roots, and they promote a range of biological activities that are essential for periodontal regeneration (Miki et al, 1987;Nakae et al, 1989;Nishimura et al, 1989;Somerman et al, 1987Somerman et al, , 1989McAllister et al, 1990).…”

Regeneration of periodontal tissues: cementogenesis revisited

“…The presence of cementum‐specific proteins remains questionable, although some putative cementum‐specific proteins have been invoked: a 55‐kDa CAP (263); a mitogenic factor (167); and a 72‐kDa protein, CEM‐1 (235). However, as the characterization and the sole expression by cementoblasts of these proteins have not been determined, the possible existence of cementum‐specific proteins remains unknown.…”

Role of Hertwig's epithelial root sheath cells in tooth root development

“…A precise characterization of the mineralized matrix as cementum is difficult, because the presence of cementumspecific proteins remains questionable. Although some putative cementum-specific proteins have been invoked such as the 56-kDa CAP (McAllister et al, 1990;Pitaru et al, 1995;Wu et al, 1996), a mitogenic factor (Nakae et al, 1991) and a 72-kDa protein (CEM-1, Slavkin et al, 1988), characterization of these proteins has been sparse and no particular cell type has been associated with their expression. In the present study, we showed that HERS cells synthesize a secreted as well as membrane-bound protein cross-reactive with a polyclonal antibody against CAP, thus supporting the idea that HERS cells are capable of producing cementum.…”