The leptin receptor in human osteoblasts and the direct effect of leptin on bone metabolism.
It is important to elucidate whether the leptin receptor, especially the long signal-transducing form of the leptin receptor (OB-Rb) is expressed in human osteoblasts. We detected the expression of human OB-Rb in cultured commercially available human osteoblasts (NHOst cells) using real-time quantitative reverse transcriptase polymerase chain reaction (RT-PCR). After confirming the expression of OB-Rb, we investigated the effect of leptin on NHOst cells. Leptin enhanced cell proliferation of the cells shown by the MTT assay. Furthermore, leptin changed the copy numbers of Bax and Bcl-2 mRNAs in the cultured cells as shown by real-time quantitative RT-PCR, although the effect was not consistent. Leptin did not change the production of osteocalcin and osteopontin by the cells. Leptin did not change the expression of OB-Rb mRNA in the cells. In conclusion, OB-Rb mRNA is expressed in cultured commercially available human osteoblasts. Leptin may have some effects on bone metabolism by directly modulating cell proliferation and apoptosis of osteoblasts in humans.
Iwamoto
I
I
Department of Obstetrics and Gynecology, Faculty of Medicine, Kagoshima University, Kagoshima, Japan. ichiro@m.kufm.kagoshima-u.ac.jp
Fujino
T
T
Douchi
T
T
D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D019254:Genes, bcl-2 / Q000235:genetics; D006801:Humans; D020738:Leptin / Q000494:pharmacology / Q000502:physiology*; D010006:Osteoblasts / Q000737:chemistry* / Q000187:drug effects*; D015675:Osteocalcin / Q000032:analysis; D053495:Osteopontin; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface / Q000235:genetics*; D054411:Receptors, Leptin; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000032:analysis; D051028:bcl-2-Associated X Protein
C494826:BAX protein, human; C515448:LEPR protein, human; D020738:Leptin; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; D054411:Receptors, Leptin; C506895:SPP1 protein, human; D012795:Sialoglycoproteins; D051028:bcl-2-Associated X Protein; D015675:Osteocalcin; D053495:Osteopontin