Expression and synthesis of bone morphogenetic proteins by osteoclasts: a possible path to anabolic bone remodeling.
Skeletal remodeling is a finely orchestrated process coupling bone formation to bone resorption. The dynamics of coupling is regulated by the microenvironment at the bone remodeling site, which in turn is influenced by the intercellular communication between cells like osteoclasts and osteoblasts. Understanding the dynamics of coupling is important in devising new therapeutic approaches to the treatment of skeletal diseases characterized by disturbances in the bone remodeling process. In this study, we report the localization of bone morphogenetic proteins (BMPs) in osteoclasts generated from primary cocultures of bone marrow cells from mouse femur and tibia with mouse calvarial osteoblasts, using immunocytochemistry and in situ hybridization. Positive staining was seen in osteoclasts for BMP-2, -4, -6, and -7. Real-time PCR was used to quantitatively confirm the expression of transcripts for BMP-2, BMP-4, and BMP-6 mRNA in murine osteoclasts. Finally, the presence of BMP-2, -4, -6, and-7 proteins was confirmed in osteoclast lysates by Western blotting. Overall, our data suggest a possible direct role for osteoclasts in promoting bone formation via expression and synthesis of BMPs, which then would play an important role in promoting the recruitment, proliferation, and differentiation of osteoblasts at bone resorption sites.
Garimella
Rama
R
Department of Pathology, University of Kansas Medical Center, Kansas City, Kansas, USA.
Tague
Sarah E
SE
Zhang
Jianghong
J
Belibi
Frank
F
Nahar
Niru
N
Sun
Ben Hua
BH
Insogna
Karl
K
Wang
Jinxi
J
Anderson
H Clarke
HC
D000135:Acid Phosphatase; D000818:Animals; D015153:Blotting, Western; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D019485:Bone Morphogenetic Proteins / Q000096:biosynthesis* / Q000235:genetics; D016723:Bone Remodeling; D018920:Coculture Techniques; D005269:Femur / Q000166:cytology; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007527:Isoenzymes; D051379:Mice; D010010:Osteoclasts / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012886:Skull / Q000166:cytology; D000071681:Tartrate-Resistant Acid Phosphatase; D013977:Tibia / Q000166:cytology
D019485:Bone Morphogenetic Proteins; D007527:Isoenzymes; D012333:RNA, Messenger; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase