Differential effects of secreted frizzled-related proteins (sFRPs) on osteoblastic differentiation of mouse mesenchymal cells and apoptosis of osteoblasts.
Secreted frizzled-related proteins (sFRPs) are modulators of Wnt signaling. This study was undertaken for definitive assessment of contribution of different sFRPs in osteoblastic differentiation of mesenchymal progenitor cells and apoptosis of osteoblasts. Treatment of C3H10T1/2 cells with sFRP-2 at concentrations of 10, 50, and 100nM and sFRP-4 at low concentrations (5nM) significantly increased Wnt-3A-induced alkaline phosphatase (ALP) activities, whereas sFRP-1 or 3 did not. Retroviral transduction of the sFRP-2 but not other sFRPs also significantly enhanced ALP activity induced by beta-glycerophosphate and ascorbic acid. Furthermore, transfection of all the sFRP expression vectors significantly increased beta-catenin/TCF reporter activity and the effects were most prominent with sFRP-2 and -4. In osteoblast apoptosis assay, only sFRP-3 increased etoposide-induced apoptosis in MC3T3-E1 mouse osteoblasts. In conclusion, we found that different repertoires of sFRPs exert differential effects on osteoblastic differentiation of mouse mesenchymal cells and cellular apoptosis of mouse osteoblasts in vitro.
Cho
Sun Wook
SW
Department of Internal Medicine, Seoul National University College of Medicine, 28 Yungun-Dong, Chongno-Gu, Seoul 110-744, Republic of Korea.
Her
Sun Ju
SJ
Sun
Hyun Jin
HJ
Choi
Ok Kyong
OK
Yang
Jae-Yeon
JY
Kim
Sang Wan
SW
Kim
Seong Yeon
SY
Shin
Chan Soo
CS
D000818:Animals; D017209:Apoptosis / Q000502:physiology; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D006023:Glycoproteins / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology*; D051379:Mice; D008809:Mice, Inbred C3H; D010006:Osteoblasts / Q000166:cytology* / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D000099274:Frizzled-Related Proteins; D000094742:Secreted Frizzled-Related Proteins
D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D000099274:Frizzled-Related Proteins; C491628:Sfrp2 protein, mouse; D000094742:Secreted Frizzled-Related Proteins; C498454:Sfrp4 protein, mouse