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Differential effects of retinoic acid and growth factors on osteoblastic markers and CD10/NEP activity in stromal‐derived osteoblasts
Author(s) -
Benayahu D.,
Fried A.,
Shamay A.,
Cunningham N.,
Blumberg S.,
Wientroub S.
Publication year - 1994
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.240560111
Subject(s) - retinoic acid , stromal cell , osteonectin , alkaline phosphatase , osteopontin , chemistry , cell culture , biglycan , microbiology and biotechnology , endocrinology , medicine , osteocalcin , biology , extracellular matrix , biochemistry , cancer research , enzyme , genetics , proteoglycan , decorin
The effects of retinoic acid (RA) on the expression of osteoblastic‐related cell makers was examined. A marrow and osteogenic cell line, MBA‐15, was analyzed by Northern blotting for the expression of bone matrix proteins. These cells constituentively express mRNA encoding for procolllagen a 2 (1), osteonectin, osteopontin, biglycan and alkaline phosphatase (ALK‐P). Gene expression was unchanged in response to RA triggering for 24hr. Furthermore, cell growth and enzymatic activities of ALK‐P and neutral endopeptidase (CD10/NEP) were studied. These parameters were examined in MBA‐15 and clonal populations representing different stages of differentiation. The cell's growth rate was unchanged, while ALK‐P activity was greatly increased during the culture period under RA treatment in MBA‐15 and in the clonal cell lines examined while CD10/NEP activity dispalyed a different pattern. MBA‐15.4, a presosteoblast cell ine, exhibited an inhibition in CD10/NEP activity at the beginning of the culture period, reaching basal level with time. This activity was greatly increased over control level in MBA‐15.6, a mature stage of osteoblasts. Furthermore, the response of cell lines to various growth factors was tested subsequent to priming the cultures with RA. A synergistic effect was monitored for ALK‐P activity in MBA‐15.4 and MBA‐15.6 cells under rh‐bone morphogenic protein (BMP‐2) and purified osteogenin (BMP‐3), and an antagonist effect was measured when cells were exposed to transforming growth factor β (TGFβ). Contrarily, BMP‐2 and BMP‐3 inhibited the CD10/NEP activity that had remained unchanged following priming of the cell with RA. Insulin‐like growth factor 1 (IGF‐1) and basic fibroblast growth factors (bFGF) did not affect either ALK‐P nor CD10/NEP activities in both cloned cells. Cellular response to bone‐seeking hormone, parathyroid hormone (PTH), and prostaglandin E 2 (PGE 2 ) was monitored by activation of intracellular cAMP. Treatment with RA caused a dramatic increase in MBA‐15.6 cell responses to PTH and PGE 2 but no significant effects could be observed in other clonal lines.