title: Matrix extracellular phosphoglycoprotein (MEPE) is highly expressed in osteocytes in human bone.
abstract: The matrix extracellular phosphoglycoprotein (MEPE) gene is highly expressed in tumors that cause oncogenic hypophosphatemic osteomalacia (OHO). MEPE is also known as one of the bone-tooth matrix proteins and is associated with bone mineralization. We developed a rabbit polyclonal antibody directed against recombinant human MEPE (rhMEPE) after cloning its cDNA from the cDNA library of a nasal tumor tissue causing OHO. Using this antibody, we analyzed the distribution of MEPE in human bones by immunohistochemistry. In bone specimens from normal subjects, MEPE was predominantly expressed by osteocytes and not by osteoblasts. In bone specimens from patients with osteomalacia, however, MEPE was focally expressed by deeply located osteocytes. We also compared the MEPE positivity of osteocytes in mineralized bone and non-mineralized osteoid obtained from patients with osteomalacia and osteoporosis. Among osteomalacia patients, MEPE positivity was seen in 87.5 +/- 8.6% of the osteocytes from mineralized bone compared with 7.8 +/- 6.4% of those from osteoid. Among osteoporosis patients, MEPE positivity was found in 95.3 +/- 0.5% of the osteocytes from mineralized bone compared with 4.9 +/- 5.7% of those from osteoid. MEPE was mainly expressed by osteocytes embedded in the matrix of mineralized bone from patients with osteomalacia or osteoporosis. Our data provide the first histological evidence that MEPE is predominantly expressed by osteocytes in human bone, with significant expression by osteocytes within mineralized bone.
authors.affiliation: Department of Orthopaedics, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita 565-0871, Japan.
authors.forename: Akihide
authors.initials: A
authors.lastname: Nampei
authors.forename: Jun
authors.initials: J
authors.lastname: Hashimoto
authors.forename: Kenji
authors.initials: K
authors.lastname: Hayashida
authors.forename: Hideki
authors.initials: H
authors.lastname: Tsuboi
authors.forename: Kenrin
authors.initials: K
authors.lastname: Shi
authors.forename: Isamu
authors.initials: I
authors.lastname: Tsuji
authors.forename: Hideaki
authors.initials: H
authors.lastname: Miyashita
authors.forename: Takao
authors.initials: T
authors.lastname: Yamada
authors.forename: Naomichi
authors.initials: N
authors.lastname: Matsukawa
authors.forename: Masayuki
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Shigeto
authors.initials: S
authors.lastname: Morimoto
authors.forename: Toshio
authors.initials: T
authors.lastname: Ogihara
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ochi
authors.forename: Hideki
authors.initials: H
authors.lastname: Yoshikawa
mesh_terms: D000818:Animals; D015153:Blotting, Western; D001842:Bone and Bones / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D016466:CHO Cells; D006224:Cricetinae; D004926:Escherichia coli; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D015870:Gene Expression; D006023:Glycoproteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007106:Immune Sera / Q000276:immunology; D010011:Osteocytes / Q000378:metabolism* / Q000473:pathology; D010018:Osteomalacia / Q000378:metabolism; D010024:Osteoporosis / Q000378:metabolism; D010750:Phosphoproteins / Q000096:biosynthesis / Q000276:immunology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology
chemical_list: D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D007106:Immune Sera; C486579:MEPE protein, human; D010750:Phosphoproteins; D011994:Recombinant Proteins