Masayoshi Kumegawa

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We have previously cloned a rabbit cDNA clone (OC-2) from an osteoclast cDNA library by the differential screening. OC-2 was found to encode a novel cysteine proteinase, tentatively called cathepsin K, which is predominantly expressed in osteoclasts. By use of a rabbit OC-2 fragment as a probe, its human counterpart was cloned from a cDNA library of(More)
Osteoclasts are multinucleate giant cells playing key roles in bone resorption. These cells solubilize mineralized bone matrix by means of acid and protease action; however, the precise mechanism of this process is not well known. Recently, we succeeded in the isolation of pure osteoclasts from rabbit bones and constructed a cDNA library. Using a(More)
To understand the molecular events coupling between cell proliferation and differentiation by elucidating genes essential for the process, we conducted a large scale gene expression analysis of an in vitro osteoclastogenesis system consisting of recombinant RANKL and mouse RAW264 cells. The entire process leading to the formation of tartrate resistant acid(More)
Bone morphogenetic proteins (BMPs) play an important role in various kinds of pattern formation and organogenesis during vertebrate development. In the skeleton, BMPs induce the differentiation of cells of chondrocytic and osteoblastic cell lineage and enhance their function. However, the action of BMPs on osteoclastic bone resorption, a process essential(More)
The patterns of gene expression for hepatocyte growth factor (HGF) and its receptor, c-Met, were revealed in the tooth germ of rat mandibular molars using RT-PCR. In situ hybridization demonstrated that the HGF gene was expressed only in the cells of the dental papilla of the tooth germ in vivo. The characteristic temporospatial distribution of HGF and(More)
A variety of studies have shown that osteoclasts originate from bone marrow, but their exact progenitors and differentiation pathway remain unclear. The treatment of mice with a high dose of 5-fluorouracil (5-FU) results in an enrichment for primitive hematopoietic progenitors; using this procedure, we prepared a new class of murine hematopoietic colonies(More)
Bone metabolism consists of osteoblast-mediated bone formation coupled to osteoclastic resorption of bone. Osteoclastic bone resorption plays an important role in normal skeletal development and the maintenance of its integrity throughout life. Although osteoclastic activity is thought to be under the control of feedback regulation by extracellular cations,(More)
Osteopetrotic (op/op) mice have a severe deficiency of osteoclasts, monocytes, and peritoneal macrophages because of a defect in the production of functional macrophage colony-stimulating factor (M-CSF) resulting from a mutation within the M-CSF gene. In this study, we examined whether daily 5-microgram injections of purified recombinant human M-CSF(More)
Milk is recommended as an excellent calcium source for bone health. Moreover, milk is considered to contain other components effective for bone health. In our previous studies, using an unfractionated bone cell culture system, we found that milk whey protein, especially its basic fraction (milk basic protein [MBP]), suppressed bone resorption. In this(More)
In bone development and regeneration, angiogenesis and bone/cartilage resorption are essential processes and are closely associated with each other, suggesting a common mediator for these two biological events. To address this interrelationship, we examined the effect of vascular endothelial growth factor (VEGF), the most critical growth factor for(More)