Expression of prostaglandin E receptor subtypes in bone: expression of EP2 in bone development.
Prostaglandin (PG) E2 displays physiological and pharmacological action in various tissues including bone. It increases intracellular Ca, and stimulates or inhibits cAMP production through the PGE receptor subtypes EP1, EP2, and EP3, respectively. These receptor subtypes have been recently cloned. In the present study, we investigate the expression of these receptor subtypes in bone tissue. RT-PCR revealed that EP1, EP2, and EP3 were expressed in rat calvariae and that osteoblastic cells (MC3T3-E1) expressed EP1 and EP2. In situ hybridization analysis using cryosection of neonatal calvariae revealed that EP2 was expressed by osteoblasts and cells not in contact with bone, probably including preosteoblasts. EP2 expression was observed at an early stage in calvarial development, at 14 days prenatal. EP2 expression was also observed at day 3 in rat bone marrow cell culture in which bone-like mineralized nodules are formed at day 8. It has been established that PGE2 response accompanying cAMP production is one of the characteristics of osteoblasts. The present results indicate that this phenotype appears at an early stage of osteoblastic differentiation and bone development.
Kasugai
S
S
Department of Pharmacology, Faculty of Dentistry, Tokyo Medical and Dental University, Japan.
Oida
S
S
Iimura
T
T
Arai
N
N
Takeda
K
K
Ohya
K
K
Sasaki
S
S
D016475:3T3 Cells / Q000166:cytology / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001483:Base Sequence; D001846:Bone Development / Q000502:physiology*; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D017931:DNA Primers / Q000737:chemistry; D015870:Gene Expression; D017403:In Situ Hybridization; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D051381:Rats; D017208:Rats, Wistar; D018078:Receptors, Prostaglandin E / Q000096:biosynthesis* / Q000235:genetics; D012886:Skull / Q000166:cytology / Q000378:metabolism
D017931:DNA Primers; D018078:Receptors, Prostaglandin E; D012313:RNA; D000242:Cyclic AMP