Sequential expression of bone morphogenetic protein, tumor necrosis factor, and their receptors in bone-forming reaction after mouse femoral marrow ablation.
Tumor necrosis factor-alpha (TNF-alpha) is considered a promoter of bone resorption and a suppressor of osteogenesis, whereas bone morphogenetic protein (BMP) is a promoter of bone formation. In the present study, the osteogenic potential of the medullary cavity after bone marrow ablation was evaluated in association with the pattern of BMP, bone morphogenetic protein receptor (BMPR), TNF-alpha, and tumor necrosis factor receptor (TNFR) expression. Immunostaining, in situ hybridization, and TRAP staining were performed following marrow ablation. By day 4, BMP-4 mRNA was detected by in situ hybridization in growing undifferentiated cells and, on day 7, the osteoblastic cells that covered abundant woven bone also showed evidence of BMP-4 expression. BMPR-IA and BMPR-II were immunolocalized from days 4 to 10 after ablation, and became negative on days 21 and 28. At 10 days postablation, osteoclasts were revealed by TRAP staining. TNF-alpha expression disappeared transiently after ablation and then reappeared on day 7, predominantly in osteoblastic cells. On days 7, 10, and 14, immunostaining for TNFR-I was observed in osteoblasts lining the woven bone and later disappeared. No evidence of TNFR-II staining was observed on osteoblastic cells throughout the reaction. From day 14, newly formed bone decreased in quantity and was replaced by hematopoietic cells and, by day 28, the bone marrow had regenerated to its original state. This study suggests that TNF-alpha is produced and secreted by the osteoblast and acts on these cells in an autocrine manner to suppress osteoblastic function. TNF-alpha may also play a role in the recruitment of osteoclasts because TRAP-positive osteoclasts appeared after TNF-alpha expression.
Shimizu
T
T
Department of Orthopaedic Surgery, School of Medicine, Shinshu University, Matsumoto, Japan. tshimiz@med.shinshu-u.ac.jp
Mehdi
R
R
Yoshimura
Y
Y
Yoshikawa
H
H
Nomura
S
S
Miyazono
K
K
Takaoka
K
K
D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D015519:Bone Density; D001853:Bone Marrow / Q000502:physiology* / Q000601:surgery; D055415:Bone Morphogenetic Protein 4; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis*; D016723:Bone Remodeling; D002454:Cell Differentiation / Q000502:physiology; D005269:Femur / Q000000981:diagnostic imaging / Q000502:physiology / Q000601:surgery; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes / Q000032:analysis; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000096:biosynthesis; D011859:Radiography; D017978:Receptors, Growth Factor / Q000096:biosynthesis*; D000071681:Tartrate-Resistant Acid Phosphatase; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; D019485:Bone Morphogenetic Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D017978:Receptors, Growth Factor; D014409:Tumor Necrosis Factor-alpha; D017346:Protein Serine-Threonine Kinases; C498212:Bmpr1a protein, mouse; C498219:Bmpr2 protein, mouse; D052005:Bone Morphogenetic Protein Receptors, Type I; D052006:Bone Morphogenetic Protein Receptors, Type II; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase