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Overexpression of Bcl2 in osteoblasts inhibits osteoblast differentiation and induces osteocyte apoptosis.
PLoS One 2011; 6(11):e27487Plos

Abstract

Bcl2 subfamily proteins, including Bcl2 and Bcl-X(L), inhibit apoptosis. As osteoblast apoptosis is in part responsible for osteoporosis in sex steroid deficiency, glucocorticoid excess, and aging, bone loss might be inhibited by the upregulation of Bcl2; however, the effects of Bcl2 overexpression on osteoblast differentiation and bone development and maintenance have not been fully investigated. To investigate these issues, we established two lines of osteoblast-specific BCL2 transgenic mice. In BCL2 transgenic mice, bone volume was increased at 6 weeks of age but not at 10 weeks of age compared with wild-type mice. The numbers of osteoblasts and osteocytes increased, but osteoid thickness and the bone formation rate were reduced in BCL2 transgenic mice with high expression at 10 weeks of age. The number of BrdU-positive cells was increased but that of TUNEL-positive cells was unaltered at 2 and 6 weeks of age. Osteoblast differentiation was inhibited, as shown by reduced Col1a1 and osteocalcin expression. Osteoblast differentiation of calvarial cells from BCL2 transgenic mice also fell in vitro. Overexpression of BCL2 in primary osteoblasts had no effect on osteoclastogenesis in co-culture with bone marrow cells. Unexpectedly, overexpression of BCL2 in osteoblasts eventually caused osteocyte apoptosis. Osteocytes, which had a reduced number of processes, gradually died with apoptotic structural alterations and the expression of apoptosis-related molecules, and dead osteocytes accumulated in cortical bone. These findings indicate that overexpression of BCL2 in osteoblasts inhibits osteoblast differentiation, reduces osteocyte processes, and causes osteocyte apoptosis.

Authors+Show Affiliations

Department of Cell Biology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22114675

Citation

Moriishi, Takeshi, et al. "Overexpression of Bcl2 in Osteoblasts Inhibits Osteoblast Differentiation and Induces Osteocyte Apoptosis." PloS One, vol. 6, no. 11, 2011, pp. e27487.
Moriishi T, Maruyama Z, Fukuyama R, et al. Overexpression of Bcl2 in osteoblasts inhibits osteoblast differentiation and induces osteocyte apoptosis. PLoS ONE. 2011;6(11):e27487.
Moriishi, T., Maruyama, Z., Fukuyama, R., Ito, M., Miyazaki, T., Kitaura, H., ... Komori, T. (2011). Overexpression of Bcl2 in osteoblasts inhibits osteoblast differentiation and induces osteocyte apoptosis. PloS One, 6(11), pp. e27487. doi:10.1371/journal.pone.0027487.
Moriishi T, et al. Overexpression of Bcl2 in Osteoblasts Inhibits Osteoblast Differentiation and Induces Osteocyte Apoptosis. PLoS ONE. 2011;6(11):e27487. PubMed PMID: 22114675.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Overexpression of Bcl2 in osteoblasts inhibits osteoblast differentiation and induces osteocyte apoptosis. AU - Moriishi,Takeshi, AU - Maruyama,Zenjiro, AU - Fukuyama,Ryo, AU - Ito,Masako, AU - Miyazaki,Toshihiro, AU - Kitaura,Hideki, AU - Ohnishi,Hidetake, AU - Furuichi,Tatsuya, AU - Kawai,Yosuke, AU - Masuyama,Ritsuko, AU - Komori,Hisato, AU - Takada,Kenji, AU - Kawaguchi,Hiroshi, AU - Komori,Toshihisa, Y1 - 2011/11/17/ PY - 2011/09/09/received PY - 2011/10/18/accepted PY - 2011/11/25/entrez PY - 2011/11/25/pubmed PY - 2012/5/4/medline SP - e27487 EP - e27487 JF - PloS one JO - PLoS ONE VL - 6 IS - 11 N2 - Bcl2 subfamily proteins, including Bcl2 and Bcl-X(L), inhibit apoptosis. As osteoblast apoptosis is in part responsible for osteoporosis in sex steroid deficiency, glucocorticoid excess, and aging, bone loss might be inhibited by the upregulation of Bcl2; however, the effects of Bcl2 overexpression on osteoblast differentiation and bone development and maintenance have not been fully investigated. To investigate these issues, we established two lines of osteoblast-specific BCL2 transgenic mice. In BCL2 transgenic mice, bone volume was increased at 6 weeks of age but not at 10 weeks of age compared with wild-type mice. The numbers of osteoblasts and osteocytes increased, but osteoid thickness and the bone formation rate were reduced in BCL2 transgenic mice with high expression at 10 weeks of age. The number of BrdU-positive cells was increased but that of TUNEL-positive cells was unaltered at 2 and 6 weeks of age. Osteoblast differentiation was inhibited, as shown by reduced Col1a1 and osteocalcin expression. Osteoblast differentiation of calvarial cells from BCL2 transgenic mice also fell in vitro. Overexpression of BCL2 in primary osteoblasts had no effect on osteoclastogenesis in co-culture with bone marrow cells. Unexpectedly, overexpression of BCL2 in osteoblasts eventually caused osteocyte apoptosis. Osteocytes, which had a reduced number of processes, gradually died with apoptotic structural alterations and the expression of apoptosis-related molecules, and dead osteocytes accumulated in cortical bone. These findings indicate that overexpression of BCL2 in osteoblasts inhibits osteoblast differentiation, reduces osteocyte processes, and causes osteocyte apoptosis. SN - 1932-6203 UR - https://www.unboundmedicine.com/medline/citation/22114675/Overexpression_of_Bcl2_in_osteoblasts_inhibits_osteoblast_differentiation_and_induces_osteocyte_apoptosis_ L2 - http://dx.plos.org/10.1371/journal.pone.0027487 DB - PRIME DP - Unbound Medicine ER -