BMP-2-induced Osterix expression is mediated by Dlx5 but is independent of Runx2

Lee, Mi-Hye; Kwon, Tae-Geon; Park, Hyo‐Sang; Wozney, John M.; Ryoo, Hyun‐Mo

doi:10.1016/j.bbrc.2003.08.058

Cited by 360 publications

(288 citation statements)

References 25 publications

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“…Although Osx has been shown to be a downstream effecter of Runx2, (52) we did not detect any alteration in Runx2 mRNA levels by FHL2. The disparity in the regulation of Osx and Runx2 expression has also been reported previously, (40,53) suggesting that Osx may also be regulated in a Runx2-independent manner. The detailed mechanism in the regulation of Osx by FHL2 awaits future analysis.…”

Section: Discussionsupporting

confidence: 75%

Four and Half Lim Protein 2 (FHL2) Stimulates Osteoblast Differentiation

Lai

Bai

Uthgenannt

et al. 2006

Journal of Bone and Mineral Research

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FHL2, a molecule that interacts with many integrins and transcription factors, was found to play an important role in osteoblast differentiation. Overexpression of FHL2 increases the accumulation of osteoblast differentiation markers and matrix mineralization, whereas FHL2 deficiency results in inhibition of osteoblast differentiation and decreased bone formation.Introduction: Integrin-matrix interaction plays a critical role in osteoblast function. It has been shown that the cytoplasmic domains of integrin ␤ subunits mediate signal transduction induced by integrin-matrix interaction. We reasoned that the identification of proteins interacting with ␤-cytoplasmic tails followed by analysis of the function of these proteins would enhance our understanding on integrin signaling and the roles of these proteins in osteoblast activities. Materials and Methods: Yeast two hybrid assay was used to identify proteins interacting with the cytoplasmic domain of integrin ␤5 subunit. The association of these proteins with integrin ␣v␤5 was confirmed by confocal analysis and co-immunoprecipitation. A stable MC3T3-E1 cells line overexpressing Four and Half Lim Protein 2 (FHL2) and mouse osteoblasts deficient in FHL2 were used to study the roles of FHL2 in osteoblast differentiation and bone formation. Matrix protein expression was determined by mRNA analysis and Western blotting. Matrix mineralization was detected by Alizarin red staining. Alkaline phosphatase activity was also measured. CT was used to determine bone histomorphometry. Results and Conclusions: FHL2 and actin-binding proteins, palladin and filamin A, were identified as proteins interacting with ␤5 cytoplasmic domain. FHL2 co-localized with ␣v␤5 at the focal adhesion sites in association with palladin and filamin A. FHL2 was also present in nuclei. Osteoblasts overexpressing FHL2 exhibited increased adhesion to and migration on matrix proteins. Conversely, FHL2 stimulation of CREB activity was dependent on integrin function because it was inhibited by Gly-Arg-Gly-Asp-Ser (GRGDS) peptide. The expression of osteoblast differentiation markers and Msx2 was upregulated, and bone matrix mineralization was increased in FHL2 overexpressing cells. In contrast, FHL2-deficient bone marrow cells and osteoblasts displayed decreased osteoblast colony formation and differentiation, respectively, compared with wildtype cells. Moreover, FHL2-deficient female mice exhibited greater bone loss than the wildtype littermates after ovariectomy. Thus, FHL2 plays an important role in osteoblast differentiation and bone formation.

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Section: Discussionsupporting

confidence: 75%

Four and Half Lim Protein 2 (FHL2) Stimulates Osteoblast Differentiation

Lai

Bai

Uthgenannt

et al. 2006

Journal of Bone and Mineral Research

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“…Specifically, Bmp-2/4 has been shown to increase Dlx-5 expression in avian calvarial explant cultures (13) and in osteoblastic cell cultures (10). In addition, the BMP2/ 4 regulation of the osteoblast differentiation markers, Runx-2, Osterix, and Alkaline phosphatase, appears to be dependent on Dlx-5 (17,19,20). Impaired PFS fusion in the Bgn/Dcn double deficient mice may be due to failure of appropriate expression of signaling molecules involved in promoting bone formation and mineralization, which is consistent with previous findings of severe osteopenia (2,5) and decreased expression of Dlx-5 in the cranial sutures.…”

Section: Discussionmentioning

confidence: 99%

Impaired posterior frontal sutural fusion in the biglycan/decorin double deficient mice

Wadhwa

Ortiz

et al. 2007

Bone

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Biglycan (Bgn) and decorin (Dcn) are highly expressed in numerous tissues in the craniofacial complex. However, their expression and function in the cranial sutures is unknown. In order to study this, we first examined the expression of biglycan and decorin in the posterior frontal suture (PFS), which predictably fuses between 21-45 days post-natal and in the non-fusing sagittal (S) suture from wildtype (Wt) mice. Our data showed that Bgn and Dcn were expressed in both cranial sutures. We then characterized the cranial suture phenotype in Bgn deficient, Dcn deficient, Bgn/Dcn double deficient, and Wt mice. At embryonic day 18.5, alizarin red/ alcian blue staining showed that the Bgn/Dcn double deficient mice had hypomineralization of the frontal and parietal craniofacial bones. Histological analysis of adult mice (45-60 days post natal) showed that the Bgn or Dcn deficient mice had no cranial suture abnormalities and immunohistochemistry staining showed increased production of Dcn in the PFS from Bgn deficient mice. To test possible compensation of Dcn in the Bgn deficient sutures we examined the Bgn/Dcn double deficient mice and found they had impaired fusion of the PFS. Semi-quantitative RT-PCR analysis of RNA from 35 day-old mice revealed increased expression of Bmp-4 and Dlx-5 in the PFS compared to their non-fusing S suture in Wt tissues and decreased expression of Dlx-5 in both PF and S sutures in the Bgn/Dcn double deficient mice compared to the Wt mice. Failure of PFS fusion and hypomineralization of the calvaria in the Bgn/Dcn double deficient mice demonstrate these extracellular matrix proteoglycans could have a role in controlling the formation and growth of the cranial vault.

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“…Dlx5 is a BMP-responsive gene activated through a responsive element in its proximal promoter. Moreover, Dlx5 interacts with the Osx promoter and mediates BMP2-induced Osx expression independently of Runx2 (Lee et al 2003, Ulsamer et al 2008. miR-141 and miR-200a have been found to act as repressors of Dlx5 and Osx expression, and it has been demonstrated that both bind to Dlx5 mRNA in vitro (Itoh et al 2009).…”

Section: Mirnas and Osteoblast Differentiationmentioning

confidence: 99%

MicroRNAs and post-transcriptional regulation of skeletal development

Gámez¹,

Rodríguez-Carballo²,

Ventura³

2014

Journal of Molecular Endocrinology

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MicroRNAs (miRNAs) have become integral nodes of post-transcriptional control of genes that confer cellular identity and regulate differentiation. Cell-specific signaling and transcriptional regulation in skeletal biology are extremely dynamic processes that are highly reliant on dose-dependent responses. As such, skeletal cell-determining genes are ideal targets for quantitative regulation by miRNAs. So far, large amounts of evidence have revealed a characteristic temporal miRNA signature in skeletal cell differentiation and confirmed the essential roles that numerous miRNAs play in bone development and homeostasis. In addition, microarray expression data have provided evidence for their role in several skeletal pathologies. Mouse models in which their expression is altered have provided evidence of causal links between miRNAs and bone abnormalities. Thus, a detailed understanding of the function of miRNAs and their tight relationship with bone diseases would constitute a powerful tool for early diagnosis and future therapeutic approaches.

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BMP-2-induced Osterix expression is mediated by Dlx5 but is independent of Runx2

Cited by 360 publications

References 25 publications

Four and Half Lim Protein 2 (FHL2) Stimulates Osteoblast Differentiation

Four and Half Lim Protein 2 (FHL2) Stimulates Osteoblast Differentiation

Impaired posterior frontal sutural fusion in the biglycan/decorin double deficient mice

MicroRNAs and post-transcriptional regulation of skeletal development

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