Impact of the microgravity environment in a 3-dimensional clinostat on osteoblast- and osteoclast-like cells.
Mechanical unloading conditions result in decreases in bone mineral density and quantity, which may be partly attributed to an imbalance in bone formation and resorption. To investigate the effect of mechanical unloading on osteoblast and osteoclast differentiation, and the expression of RANKL and OPG genes in osteoblasts, we used a three-dimensional (3D) clinostat system simulating microgravity to culture MC3T3-E1 and RAW264.7 cells. Long-term exposure (7 days) of MC3T3-E1 cells to microgravity in the 3D clinostat inhibited the expression of Runx2, Osterix, type I collagen alphaI chain, RANKL and OPG genes. Similarly, 3D clinostat exposure inhibited the enhancement of beta3-integrin gene expression, which normally induced by sRANKL stimulation in RAW264.7 cells. These results, taken together, demonstrate that long-term 3D clinostat exposure inhibits the differentiation of MC3T3-E1 cells together with suppression of RANKL and OPG gene expression, as well as the RANKL-dependent cellular fusion of RAW264.7 cells, suggesting that long-term mechanical unloading suppresses bone formation and resorption.
Makihira
Seicho
S
Department of Medical Design and Engineering, Division of Oral Health Engineering, Institute for Oral Health Science, Hiroshima University Faculty of Dentistry,1-2-3 Kasumi Minami-ku, Hiroshima 734-8553, Japan. seicho@hiroshima-u.ac.jp
Kawahara
Yumi
Y
Yuge
Louis
L
Mine
Yuichi
Y
Nikawa
Hiroki
H
D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D018929:Cell Culture Techniques / Q000295:instrumentation*; D002460:Cell Line; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D039661:Integrin beta3 / Q000235:genetics / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology* / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology* / Q000378:metabolism; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism; D053245:RANK Ligand / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase; D014893:Weightlessness
D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; C499636:DC-STAMP protein, mouse; D039661:Integrin beta3; D007527:Isoenzymes; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase