Transcriptional regulation of BMP-2 activated genes in osteoblasts using gene expression microarray analysis role of DLX2 and DLX5 transcription factors

Harris, S. E.; Guo, Dayong; Harris, Marie A.; Krishnaswamy, Arvind; Lichtler, Alex

doi:10.2741/1170

Cited by 69 publications

(47 citation statements)

References 19 publications

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“…Many extracellular and intracellular proteins, such as Dlx-5, regulate the Bmp-2/ 4 signaling pathway. 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).…”

Section: Discussionmentioning

confidence: 97%

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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Section: Discussionmentioning

confidence: 97%

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

Wadhwa

Ortiz

et al. 2007

Bone

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“…HtrA1 Overexpression Prevents BMP-2-induced Mineralization-BMP-2 accelerates the appearance of mineralized nodules in 2T3 cells (22,23), and HtrA1 has been demonstrated to inhibit signaling of BMP family members in vitro (14). Therefore, to investigate whether the overexpression of HtrA1 could suppress the effect of BMP-2 on osteoblast mineralization, wild-type cells and C2 cells were cultured in the presence of recombinant BMP-2.…”

Section: Htra1mentioning

confidence: 99%

“…Several complementary approaches were taken. First, we determined the expression pattern of HtrA1 in differentiating 2T3 osteoblast cells, an in vitro model system of bone formation (22)(23)(24)(25). Second, the effects of overexpressing and knocking down expression of HtrA1 were assessed with respect to matrix mineralization, and the response of HtrA1 overexpressing cells to BMP-2 was determined.…”

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confidence: 99%

HtrA1 Inhibits Mineral Deposition by Osteoblasts

Hadfield

Rock

Inkson

et al. 2008

Journal of Biological Chemistry

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HtrA1 is a secreted multidomain protein with serine protease activity. In light of increasing evidence implicating this protein in the regulation of skeletal development and pathology, we investigated the role of HtrA1 in osteoblast mineralization and identified domains essential for this activity. We demonstrate increased HtrA1 expression in differentiating 2T3 osteoblasts prior to the appearance of mineralization. HtrA1 is subsequently down-regulated in fully mineralized cultures. The functional role of HtrA1 in matrix calcification was investigated using three complementary approaches. First, we transfected a full-length HtrA1 expression plasmid into 2T3 cells and showed that overexpression of HtrA1 delayed mineralization, reduced expression of Cbfa1 and collagen type I mRNA, and prevented BMP-2-induced mineralization. Second, knocking down HtrA1 expression using short interfering RNA induced mineral deposition by 2T3 cells. Third, by expressing a series of recombinant HtrA1 proteins, we demonstrated that the protease domain and the PDZ domain are essential for the inhibitory effect of HtrA1 on osteoblast mineralization. Finally, we tested whether HtrA1 cleaves specific matrix proteins that are known to regulate osteoblast differentiation, mineralization, and/or BMP-2 activity. Full-length recombinant HtrA1 cleaved recombinant decorin, fibronectin, and matrix Gla protein. Both the protease domain and the PDZ domain were necessary for the cleavage of matrix Gla protein, whereas the PDZ domain was not required for the cleavage of decorin or fibronectin. Type I collagen was not cleaved by recombinant HtrA1. These results suggest that HtrA1 may regulate matrix calcification via the inhibition of BMP-2 signaling, modulating osteoblast gene expression, and/or via the degradation of specific matrix proteins.Mammalian HtrA1 is a member of the family of HtrA (high temperature requirement) proteins that were originally identified in bacteria (1). These proteins are characterized by the presence of a trypsin-like serine protease domain and either one or two PDZ domains. However, in contrast to bacterial HtrA, mammalian HtrA1 is secreted, and it also contains an IGFBP 4 /mac25-like domain and a Kazal-type inhibitor domain at the N terminus (2, 3). Evidence is now accumulating to suggest that HtrA1 is involved in the development and progression of several pathologies. HtrA1 has been found to exhibit properties of a tumor suppressor protein, as its expression is downregulated in many cancer cell lines (2, 4), low levels of HtrA1 are detected in cancerous tissue compared with normal tissues (4, 5), and overexpression of this protein inhibits tumor cell growth in vivo and in vitro (4, 5). HtrA1 expression is also markedly up-regulated in several diseases, including rheumatoid arthritis and osteoarthritis (3, 6 -8), Alzheimer disease (9), and Duchenne muscular dystrophy (10). In addition, a single-nucleotide polymorphism in the gene encoding HtrA1 has been shown to increase susceptibility to age-related macular degeneration (...

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“…This allowed us to test the role of endogenous Dlx2, using a retroviral vector encoding a chimeric protein in which the Dlx2 homeodomain had been fused to the Engrailed repressor domain (Fig. 4 A) (see Material and Methods), thus converting Dlx2-mediated transactivation into repression (Harris et al, 2003;Woda et al, 2003;Kaji and Artinger, 2004) (Fig. 4 A, E).…”

Section: Dlx2 Acts Potently Neurogenic In Adult Sez Cells In Vitromentioning

confidence: 99%

A Dlx2- and Pax6-Dependent Transcriptional Code for Periglomerular Neuron Specification in the Adult Olfactory Bulb

Brill¹,

Snapyan²,

Wohlfrom³

et al. 2008

Journal of Neuroscience

187

222

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Distinct olfactory bulb (OB) interneurons are thought to become specified depending on from which of the different subregions lining the lateral ventricle wall they originate, but the role of region-specific transcription factors (TFs) in the generation of OB interneurons diversity is still poorly understood. Despite the crucial roles of the Dlx family of TFs for patterning and neurogenesis in the ventral telencephalon during embryonic development, their role in adult neurogenesis has not yet been addressed. Here we show that in the adult brain, Dlx 1 and Dlx2 are expressed in progenitors of the lateral but not the dorsal subependymal zone (SEZ), thus exhibiting a striking regional specificity. Using retroviral vectors to examine the function of Dlx2 in a cell-autonomous manner, we demonstrate that this TF is necessary for neurogenesis of virtually all OB interneurons arising from the lateral SEZ. Beyond its function in generic neurogenesis, Dlx2 also plays a crucial role in neuronal subtype specification in the OB, promoting specification of adult-born periglomerular neurons (PGNs) toward a dopaminergic fate. Strikingly, Dlx2 requires interaction with Pax6, because Pax6 deletion blocks Dlx2-mediated PGN specification. Thus, Dlx2 wields a dual function by first instructing generic neurogenesis from adult precursors and subsequently specifying PGN subtypes in conjunction with Pax6.

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Transcriptional regulation of BMP-2 activated genes in osteoblasts using gene expression microarray analysis role of DLX2 and DLX5 transcription factors

Cited by 69 publications

References 19 publications

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

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

HtrA1 Inhibits Mineral Deposition by Osteoblasts

A Dlx2- and Pax6-Dependent Transcriptional Code for Periglomerular Neuron Specification in the Adult Olfactory Bulb

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