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Morozumi A. High concentration of sodium butyrate suppresses osteoblastic differentiation and mineralized nodule formation in ROS17/2.8 cells. J Oral Sci 2012; 53:509-16. [PMID: 22167038 DOI: 10.2334/josnusd.53.509] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
Periodontitis is a destructive disease that is likely the result of the activities of different microbial complexes, including anaerobic Gram-negative periodontopathic bacteria. Butyric acid (sodium butyrate; BA) is a major metabolic by-product of anaerobic Gram-negative periodontopathic bacteria present in subgingival plaque. This study was undertaken to examine the effect of BA on the expression of osteogenesis-related transcription factors and mineralized nodule formation in osteoblastic ROS17/2.8 cells. The cells were cultured with 0 (control), 10(-5), 10(-4), or 10(-3) M BA for up to 7 days. The gene and protein expression levels of transcription factors such as Runx2, Osterix, Dlx5, Msx2, and AJ18, as well as extracellular matrix proteins such as bone sialoprotein (BSP) and osteocalcin, were examined using real-time PCR and Western blotting, respectively. Mineralized nodule formation was detected by alizarin red staining. The expression of Runx2, Osterix, Dlx5, and Msx2 decreased significantly in the presence of 10(-3 )M BA compared to the control, whereas AJ18 expression increased significantly. Mineralized nodule formation decreased markedly in the presence of 10(-3) M BA. Alkaline phosphatase activity and the expression of bone sialoprotein and osteocalcin decreased significantly in the presence of 10(-3) M BA compared to the control. These results suggest that 10(-3) M BA suppresses osteoblastic differentiation and mineralized nodule formation in ROS17/2.8 cells.
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Affiliation(s)
- Akira Morozumi
- Department of Oral Health Sciences, Nihon University School of Dentistry, Tokyo, Japan.
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102
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Sternberg H, Murai JT, Erickson IE, Funk WD, Das S, Wang Q, Snyder E, Chapman KB, Vangsness CT, West MD. A human embryonic stem cell-derived clonal progenitor cell line with chondrogenic potential and markers of craniofacial mesenchyme. Regen Med 2012; 7:481-501. [PMID: 22519755 DOI: 10.2217/rme.12.29] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
AIMS We screened 100 diverse human embryonic stem-derived progenitor cell lines to identify novel lines with chondrogenic potential. MATERIALS & METHODS The 4D20.8 cell line was compared with mesenchymal stem cells and dental pulp stem cells by assessing osteochondral markers using immunohistochemical methods, gene expression microarrays, quantitative real-time PCR and in vivo repair of rat articular condyles. RESULTS 4D20.8 expressed the site-specific gene markers LHX8 and BARX1 and robustly upregulated chondrocyte markers upon differentiation. Differentiated 4D20.8 cells expressed relatively low levels of COL10A1 and lacked IHH and CD74 expression. Transplantation of 4D20.8 cells into experimentally induced defects in the femoral condyle of athymic rats resulted in cartilage and bone differentiation approximating that of the original tissue architecture. Relatively high COL2A1 and minimal COL10A1 expression occurred during differentiation in HyStem-C hydrogel with TGF-β3 and GDF-5. CONCLUSION Human embryonic stem cell-derived embryonic progenitor cell lines may provide a novel means of generating purified site-specific osteochondral progenitor cell lines that are useful in research and therapy.
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103
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Okano T, Kelley MW. Stem cell therapy for the inner ear: recent advances and future directions. Trends Amplif 2012; 16:4-18. [PMID: 22514095 DOI: 10.1177/1084713812440336] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In vertebrates, perception of sound, motion, and balance is mediated through mechanosensory hair cells located within the inner ear. In mammals, hair cells are only generated during a short period of embryonic development. As a result, loss of hair cells as a consequence of injury, disease, or genetic mutation, leads to permanent sensory deficits. At present, cochlear implantation is the only option for profound hearing loss. However, outcomes are still variable and even the best implant cannot provide the acuity of a biological ear. The recent emergence of stem cell technology has the potential to open new approaches for hair cell regeneration. The goal of this review is to summarize the current state of inner ear stem cell research from a viewpoint of its clinical application for inner ear disorders to illustrate how complementary studies have the potential to promote and refine stem cell therapies for inner ear diseases. The review initially discusses our current understanding of the genetic pathways that regulate hair cell formation from inner ear progenitors during normal development. Subsequent sections discuss the possible use of endogenous inner ear stem cells to induce repair as well as the initial studies aimed at transplanting stem cells into the ear.
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104
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Mizuhashi K, Kanamoto T, Ito M, Moriishi T, Muranishi Y, Omori Y, Terada K, Komori T, Furukawa T. OBIF, an osteoblast induction factor, plays an essential role in bone formation in association with osteoblastogenesis. Dev Growth Differ 2012; 54:474-80. [DOI: 10.1111/j.1440-169x.2012.01333.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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105
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Cajal M, Lawson KA, Hill B, Moreau A, Rao J, Ross A, Collignon J, Camus A. Clonal and molecular analysis of the prospective anterior neural boundary in the mouse embryo. Development 2012; 139:423-36. [PMID: 22186731 DOI: 10.1242/dev.075499] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In the mouse embryo the anterior ectoderm undergoes extensive growth and morphogenesis to form the forebrain and cephalic non-neural ectoderm. We traced descendants of single ectoderm cells to study cell fate choice and cell behaviour at late gastrulation. In addition, we provide a comprehensive spatiotemporal atlas of anterior gene expression at stages crucial for anterior ectoderm regionalisation and neural plate formation. Our results show that, at late gastrulation stage, expression patterns of anterior ectoderm genes overlap significantly and correlate with areas of distinct prospective fates but do not define lineages. The fate map delineates a rostral limit to forebrain contribution. However, no early subdivision of the presumptive forebrain territory can be detected. Lineage analysis at single-cell resolution revealed that precursors of the anterior neural ridge (ANR), a signalling centre involved in forebrain development and patterning, are clonally related to neural ectoderm. The prospective ANR and the forebrain neuroectoderm arise from cells scattered within the same broad area of anterior ectoderm. This study establishes that although the segregation between non-neural and neural precursors in the anterior midline ectoderm is not complete at late gastrulation stage, this tissue already harbours elements of regionalisation that prefigure the later organisation of the head.
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Affiliation(s)
- Marieke Cajal
- Université Paris Diderot, Sorbonne Paris Cité, Institut Jacques Monod, UMR7592 CNRS, F-75013 Paris, France
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106
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Nishimura R, Hata K, Matsubara T, Wakabayashi M, Yoneda T. Regulation of bone and cartilage development by network between BMP signalling and transcription factors. J Biochem 2012; 151:247-54. [PMID: 22253449 DOI: 10.1093/jb/mvs004] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Bone morphogenetic protein(s) (BMP) are very powerful cytokines that induce bone and cartilage formation. BMP also stimulate osteoblast and chondrocyte differentiation. During bone and cartilage development, BMP regulates the expression and/or the function of several transcription factors through activation of Smad signalling. Genetic studies revealed that Runx2, Osterix and Sox9, all of which function downstream of BMP, play essential roles in bone and/or cartilage development. In addition, two other transcription factors, Msx2 and Dlx5, which interact with BMP signalling, are involved in bone and cartilage development. The importance of these transcription factors in bone and cartilage development has been supported by biochemical and cell biological studies. Interestingly, BMP is regulated by several negative feedback systems that appear necessary for fine-tuning of bone and cartilage development induced by BMP. Thus, BMP harmoniously regulates bone and cartilage development by forming network with several transcription factors.
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Affiliation(s)
- Riko Nishimura
- Department of Molecular and Cellular Biochemistry, Osaka University Graduate School of Dentistry.
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107
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Redundant functions of Rac GTPases in inner ear morphogenesis. Dev Biol 2011; 362:172-86. [PMID: 22182523 DOI: 10.1016/j.ydbio.2011.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 11/10/2011] [Accepted: 12/02/2011] [Indexed: 11/21/2022]
Abstract
Development of the mammalian inner ear requires coordination of cell proliferation, cell fate determination and morphogenetic movements. While significant progress has been made in identifying developmental signals required for inner ear formation, less is known about how distinct signals are coordinated by their downstream mediators. Members of the Rac family of small GTPases are known regulators of cytoskeletal remodeling and numerous other cellular processes. However, the function of Rac GTPases in otic development is largely unexplored. Here, we show that Rac1 and Rac3 redundantly regulate many aspects of inner ear morphogenesis. While no morphological defects were observed in Rac3(-/-) mice, Rac1(CKO); Rac3(-/-) double mutants displayed enhanced vestibular and cochlear malformations compared to Rac1(CKO) single mutants. Moreover, in Rac1(CKO); Rac3(-/-) mutants, we observed compromised E-cadherin-mediated cell adhesion, reduced cell proliferation and increased cell death in the early developing otocyst, leading to a decreased size and malformation of the membranous labyrinth. Finally, cochlear extension was severely disrupted in Rac1(CKO); Rac3(-/-) mutants, accompanied by a loss of epithelial cohesion and formation of ectopic sensory patches underneath the cochlear duct. The compartmentalized expression of otic patterning genes within the Rac1(CKO); Rac3(-/-) mutant otocyst was largely normal, however, indicating that Rac proteins regulate inner ear morphogenesis without affecting cell fate specification. Taken together, our results reveal an essential role for Rac GTPases in coordinating cell adhesion, cell proliferation, cell death and cell movements during otic development.
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108
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Singh M, Del Carpio-Cano FE, Monroy MA, Popoff SN, Safadi FF. Homeodomain transcription factors regulate BMP-2-induced osteoactivin transcription in osteoblasts. J Cell Physiol 2011; 227:390-9. [PMID: 21503878 DOI: 10.1002/jcp.22791] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Osteoactivin (OA) is required for the differentiation of osteoblast cells. OA expression is stimulated by bone morphogenetic protein-2 (BMP-2). BMP-2 recruits homeodomain transcription factors Dlx3, Dlx5, and Msx2 to selectively activate or repress transcription of osteogenic genes and hence tightly regulate their transcription during osteoblast differentiation. Considering the key roles of Dlx3, Dlx5, and Msx2 in osteoblast differentiation, here we hypothesize that homeodomain proteins regulate BMP-2-induced OA transcription during osteoblast differentiation. Four classical homeodomain binding sites were identified in the proximal 0.96 kb region of rat OA promoter. Deletions and mutagenesis studies of the OA promoter region indicated that all four homeodomain binding sites are crucial for BMP-2-induced OA promoter activity. Simultaneous disruption of homeodomain binding sites at -852 and -843 of the transcription start site of OA gene significantly decreased the BMP-2-induced OA transcription and inhibited binding of Dlx3, Dlx5, and Msx2 proteins to the OA promoter. Dlx3 and Dlx5 proteins were found to activate the OA transcription, whereas, Msx2 suppressed BMP-2-induced OA transcription. Using chromatin immunoprecipitation assays, we demonstrated that the OA promoter is predominantly occupied by Dlx3 and Dlx5 during the proliferation and matrix maturation stages of osteoblast differentiation, respectively. During the matrix mineralization stage, BMP-2 robustly enhanced the recruitment of Dlx5 and to a lesser extent of Dlx3 and Msx2 to the OA promoter region. Collectively, our results show that the BMP-2-induced OA transcription is differentially regulated by Dlx3, Dlx5, and Msx2 during osteoblast differentiation.
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Affiliation(s)
- Maneet Singh
- Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania 19140, USA
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109
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Makishima T, Hochman L, Armstrong P, Rosenberger E, Ridley R, Woo M, Perachio A, Wood S. Inner ear dysfunction in caspase-3 deficient mice. BMC Neurosci 2011; 12:102. [PMID: 21988729 PMCID: PMC3208590 DOI: 10.1186/1471-2202-12-102] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 10/12/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Caspase-3 is one of the most downstream enzymes activated in the apoptotic pathway. In caspase-3 deficient mice, loss of cochlear hair cells and spiral ganglion cells coincide closely with hearing loss. In contrast with the auditory system, details of the vestibular phenotype have not been characterized. Here we report the vestibular phenotype and inner ear anatomy in the caspase-3 deficient (Casp3(-/-)) mouse strain. RESULTS Average ABR thresholds of Casp3(-/-) mice were significantly elevated (P < 0.05) compared to Casp3(+/-) mice and Casp3(+/+) mice at 3 months of age. In DPOAE testing, distortion product 2F1-F2 was significantly decreased (P < 0.05) in Casp3(-/-) mice, whereas Casp3(+/-) and Casp3(+/+) mice showed normal and comparable values to each other. Casp3(-/-) mice were hyperactive and exhibited circling behavior when excited. In lateral canal VOR testing, Casp3(-/-) mice had minimal response to any of the stimuli tested, whereas Casp3(+/-) mice had an intermediate response compared to Casp3(+/+) mice. Inner ear anatomical and histological analysis revealed gross hypomorphism of the vestibular organs, in which the main site was the anterior semicircular canal. Hair cell numbers in the anterior- and lateral crista, and utricle were significantly smaller in Casp3(-/-) mice whereas the Casp3(+/-) and Casp3(+/+) mice had normal hair cell numbers. CONCLUSIONS These results indicate that caspase-3 is essential for correct functioning of the cochlea as well as normal development and function of the vestibule.
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Affiliation(s)
- Tomoko Makishima
- Department of Otolaryngology, University of Texas Medical Branch, Galveston, Texas, USA.
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110
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Brown AS, Epstein DJ. Otic ablation of smoothened reveals direct and indirect requirements for Hedgehog signaling in inner ear development. Development 2011; 138:3967-76. [PMID: 21831920 DOI: 10.1242/dev.066126] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In mouse embryos lacking sonic hedgehog (Shh), dorsoventral polarity within the otic vesicle is disrupted. Consequently, ventral otic derivatives, including the cochlear duct and saccule, fail to form, and dorsal otic derivatives, including the semicircular canals, endolymphatic duct and utricle, are malformed or absent. Since inner ear patterning and morphogenesis are heavily dependent on extracellular signals derived from tissues that are also compromised by the loss of Shh, the extent to which Shh signaling acts directly on the inner ear for its development is unclear. To address this question, we generated embryos in which smoothened (Smo), an essential transducer of Hedgehog (Hh) signaling, was conditionally inactivated in the otic epithelium (Smo(ecko)). Ventral otic derivatives failed to form in Smo(ecko) embryos, whereas vestibular structures developed properly. Consistent with these findings, we demonstrate that ventral, but not dorsal, otic identity is directly dependent on Hh. The role of Hh in cochlear-vestibular ganglion (cvg) formation is more complex, as both direct and indirect signaling mechanisms are implicated. Our data suggest that the loss of cvg neurons in Shh(-/-) animals is due, in part, to an increase in Wnt responsiveness in the otic vesicle, resulting in the ectopic expression of Tbx1 in the neurogenic domain and subsequent repression of Ngn1 transcription. A mitogenic role for Shh in cvg progenitor proliferation was also revealed in our analysis of Smo(ecko) embryos. Taken together, these data contribute to a better understanding of the intrinsic and extrinsic signaling properties of Shh during inner ear development.
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Affiliation(s)
- Alexander S Brown
- Department of Genetics, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, Philadelphia, PA 19104, USA
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111
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A symphony of regulations centered on p63 to control development of ectoderm-derived structures. J Biomed Biotechnol 2011; 2011:864904. [PMID: 21716671 PMCID: PMC3118300 DOI: 10.1155/2011/864904] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Revised: 01/25/2011] [Accepted: 03/16/2011] [Indexed: 12/27/2022] Open
Abstract
The p53-related transcription factor p63 is critically important for basic cellular functions during development of the ectoderm and derived structure and tissues, including skin, limb, palate, and hair. On the one side, p63 is required to sustain the proliferation of keratinocyte progenitors, while on the other side it is required for cell stratification, commitment to differentiate, cell adhesion, and epithelial-mesenchymal signaling. Molecules that are components or regulators of the p63 pathway(s) are rapidly being identified, and it comes with no surprise that alterations in the p63 pathway lead to congenital conditions in which the skin and other ectoderm-derived structures are affected. In this paper, we summarize the current knowledge of the molecular and cellular regulations centered on p63, derived from the comprehension of p63-linked human diseases and the corresponding animal models, as well as from cellular models and high-throughput molecular approaches. We point out common themes and features, that allow to speculate on the possible role of p63 downstream events and their potential exploitation in future attempts to correct the congenital defect in preclinical studies.
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112
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Bouhali K, Dipietromaria A, Fontaine A, Caburet S, Barbieri O, Bellessort B, Fellous M, Veitia RA, Levi G. Allelic reduction of Dlx5 and Dlx6 results in early follicular depletion: a new mouse model of primary ovarian insufficiency. Hum Mol Genet 2011; 20:2642-50. [PMID: 21505076 DOI: 10.1093/hmg/ddr166] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Primary ovarian insufficiency (POI) is characterized by the loss of ovarian function before the age of 40 in humans. Although most cases of POI are idiopathic, many are familial, underlying a genetic origin of the disease. Mutations in genes involved in the control of steroidogenesis, such as NR5A1 (SF-1, Steroidogenic Factor 1), CYP17, CYP19A1 (aromatase), StAR (Steroidogenic Acute Regulatory), and the forkhead transcription factor FOXL2 have been associated with different forms of POI. In males, the homeobox transcription factors Dlx5 and Dlx6 are involved in the control of steroidogenesis through the activation of GATA4-induced-StAR transcription. Here, we analyze the potential involvement of Dlx5 and Dlx6 in female reproduction. To this end, we make use of an existing mouse model in which Dlx5 and Dlx6 are simultaneously disrupted. We show that: (i) allelic reduction of Dlx5 and Dlx6 in the mouse results in a POI-like phenotype, characterized by reduced fertility and early follicular exhaustion; (ii) in granulosa cell lines, a reciprocal regulation exists between Dlx5 and Foxl2; (iii) in the mouse ovary, allelic reduction of Dlx5/6 results in the upregulation of Foxl2. We propose that the mutual regulation between Dlx5/6 and Foxl2 and their opposite effects on StAR expression might contribute to determine the homeostatic control of steroidogenesis within the ovary. Dysregulation of this homeostatic control would result in abnormal follicular maturation and reduced fertility. Our results bring new elements to our conceptual model of follicle maturation and maintenance and provide new potential genetic targets for cases of familial POI.
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Affiliation(s)
- Kamal Bouhali
- Evolution des Régulations Endocriniennes, CNRS UMR 7221, Muséum National d'Histoire Naturelle, Paris, France
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113
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Abstract
The transcription factor p63 is essential for the formation of the epidermis and other stratifying epithelia. This is clearly demonstrated by the severe abnormality of p63-deficient mice and by the development of certain types of ectodermal dysplasias in humans as a result of p63 mutations. Investigation of the in vivo functions of p63 is complicated by the occurrence of 10 different splicing isoforms and by its interaction with the other family members, p53 and p73. In vitro and in vivo models have been used to unravel the functions of p63 and its different isoforms, but the results or their interpretation are often contradictory. This review focuses on what mammalian in vivo models and patient studies have taught us in the last 10 years.
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Affiliation(s)
- Hans Vanbokhoven
- Department of Human Genetics, Molecular Neurogenetics Unit, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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114
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Haugas M, Lilleväli K, Hakanen J, Salminen M. Gata2 is required for the development of inner ear semicircular ducts and the surrounding perilymphatic space. Dev Dyn 2011; 239:2452-69. [PMID: 20652952 DOI: 10.1002/dvdy.22373] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Gata2 has essential roles in the development of many organs. During mouse inner ear morphogenesis, it is expressed in otic vesicle and the surrounding periotic mesenchyme from early on, but no defects in the ear development of Gata2 null mice have been observed before lethality at embryonic day (E) 10.5. Here, we used conditional gene targeting to reveal the role of Gata2 at later stages of inner ear development. We show that Gata2 is critically required from E14.5-E15.5 onward for vestibular morphogenesis. Without Gata2 the semicircular ducts fail to grow to their normal size and the surrounding mesenchymal cells are not removed properly to generate the perilymphatic space. Gata2 is the first factor known to control the clearing of the vestibular perilymphatic mesenchyme, but interestingly, it is not required for the formation of the cochlear perilymphatic areas, suggesting distinct molecular control for these processes.
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Affiliation(s)
- Maarja Haugas
- Department of Veterinary Biosciences, University of Helsinki, Finland
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115
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Gitton Y, Benouaiche L, Vincent C, Heude E, Soulika M, Bouhali K, Couly G, Levi G. Dlx5 and Dlx6 expression in the anterior neural fold is essential for patterning the dorsal nasal capsule. Development 2011; 138:897-903. [PMID: 21270050 DOI: 10.1242/dev.057505] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Morphogenesis of the vertebrate facial skeleton depends upon inductive interactions between cephalic neural crest cells (CNCCs) and cephalic epithelia. The nasal capsule is a CNCC-derived cartilaginous structure comprising a ventral midline bar (mesethmoid) overlaid by a dorsal capsule (ectethmoid). Although Shh signalling from the anterior-most region of the endoderm (EZ-I) patterns the mesethmoid, the cues involved in ectethmoid induction are still undefined. Here, we show that ectethmoid formation depends upon Dlx5 and Dlx6 expression in a restricted ectodermal territory of the anterior neural folds, which we name NF-ZA. In both chick and mouse neurulas, Dlx5 and Dlx6 expression is mostly restricted to NF-ZA. Simultaneous Dlx5 and Dlx6 inactivation in the mouse precludes ectethmoid formation, while the mesethmoid is still present. Consistently, siRNA-mediated downregulation of Dlx5 and Dlx6 in the cephalic region of the early avian neurula specifically prevents ectethmoid formation, whereas other CNCC-derived structures, including the mesethmoid, are not affected. Similarly, NF-ZA surgical removal in chick neurulas averts ectethmoid development, whereas grafting a supernumerary NF-ZA results in an ectopic ectethmoid. Simultaneous ablation or grafting of both NF-ZA and EZ-I result, respectively, in the absence or duplication of both dorsal and ventral nasal capsule components. The present work shows that early ectodermal and endodermal signals instruct different contingents of CNCCs to form the ectethmoid and the mesethmoid, which then assemble to form a complete nasal capsule.
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Affiliation(s)
- Yorick Gitton
- Evolution des Régulations Endocriniennes, CNRS UMR 7221, Muséum National d'Histoire Naturelle, Paris, France
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116
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Gordon CT, Brinas IML, Rodda FA, Bendall AJ, Farlie PG. Role of Dlx genes in craniofacial morphogenesis: Dlx2 influences skeletal patterning by inducing ectomesenchymal aggregation in ovo. Evol Dev 2011; 12:459-73. [PMID: 20883215 DOI: 10.1111/j.1525-142x.2010.00432.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Dlx homeodomain transcription factors are expressed in neural crest-derived mesenchyme of the pharyngeal arches and are required for patterning of the craniofacial skeleton. However, the cellular and molecular mechanisms by which Dlx factors control skeletogenesis in the facial primordia are unclear. We have investigated the function of Dlx2 and Dlx5 by sustained misexpression in ovo. We find that RCAS-Dlx2- and RCAS-Dlx5-infected avian embryos exhibit very similar patterns of local, stereotypical changes in skeletal development in the upper jaw. The changes include ectopic dermal bone along the jugal arch, and ectopic cartilages that develop between the quadrate and the trabecula. The ectopic cartilage associated with the trabecula is reminiscent of a normally occurring element in this region in some bird taxa. Analysis of the distribution of RCAS-Dlx2-infected cells suggests that Dlx2 induces aggregation of undifferentiated mesenchyme, which subsequently develops into the ectopic skeletal elements. Comparison of infected embryos with restricted or widespread misexpression, and of embryos in which Dlx genes were delivered to migratory or postmigratory neural crest, indicate that there are limited regions of competence in which the ectopic elements can arise. The site-specific differentiation program that the aggregates undergo may be dependent on local environmental signals. Our results suggest that Dlx factors mediate localization of ectomesenchymal subpopulations within the pharyngeal arches and in doing so define where skeletogenic condensations will arise. Consequently, variation in Dlx expression or activity may have influenced the morphology of jaw elements during vertebrate evolution.
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Affiliation(s)
- Christopher T Gordon
- Craniofacial Development Laboratory, Murdoch Children's Research Institute, Royal Children's Hospital, Parkville 3052, Australia
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117
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Sajan SA, Rubenstein JLR, Warchol ME, Lovett M. Identification of direct downstream targets of Dlx5 during early inner ear development. Hum Mol Genet 2011; 20:1262-73. [PMID: 21227998 DOI: 10.1093/hmg/ddq567] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Dlx5, a homeobox transcription factor, plays a key role in the development of many organ systems. It is a candidate gene for human split-hand/split-foot type 1 malformation associated with sensorineural hearing loss. A deletion of one of its enhancers has been implicated in human craniofacial defects/hearing loss and it has also been associated with autism. However, little is known of how Dlx5 exerts its regulatory effects. We identified direct targets of Dlx5 in the mouse inner ear by gene expression profiling wild-type and Dlx5 null otic vesicles from embryonic stages E10 and E10.5. Four hundred genes were differentially expressed. We examined the genomic DNA sequences in the promoter regions of these genes for (i) previously described Dlx5 binding sites, (ii) novel 12 bp long motifs with a canonical homeodomain element shared by two or more genes and (iii) 100% conservation of these motifs in promoters of human orthologs. Forty genes passed these filters, 12 of which are expressed in the otic vesicle in domains that overlap with Dlx5. Chromatin immunoprecipitation using a Dlx5 antibody confirmed direct binding of Dlx5 to promoters of seven of these (Atbf1, Bmper, Large, Lrrtm1, Msx1, Ebf1 and Lhx1) in a cell line over-expressing Dlx5. Bmper and Lrrtm1 were up-regulated in this cell line, further supporting their identification as targets of Dlx5 in the inner ear and potentially in other organs. These direct targets support a model in which Bmp signaling is downstream of Dlx5 in the early inner ear and provide new insights into how the Dlx5 regulatory cascade is initiated.
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Affiliation(s)
- Samin A Sajan
- Department of Genetics, Central Institute for the Deaf, Washington University School of Medicine, 4566 Scott Ave, St Louis, MO 63110, USA
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Jang WG, Kim EJ, Lee KN, Son HJ, Koh JT. AMP-activated protein kinase (AMPK) positively regulates osteoblast differentiation via induction of Dlx5-dependent Runx2 expression in MC3T3E1 cells. Biochem Biophys Res Commun 2010; 404:1004-9. [PMID: 21187071 DOI: 10.1016/j.bbrc.2010.12.099] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2010] [Accepted: 12/20/2010] [Indexed: 02/06/2023]
Abstract
This study examined the role of AMPK activation in osteoblast differentiation and the underlining mechanism. An AMPK activator (AICAR or metformin) stimulated osteoblast differentiation with increases in ALP and OC protein production as well as the induction of AMPK phosphorylation in MC3T3E1 cells. In addition, metformin induced the phosphorylation of Smad1/5/8 and expression of Dlx5 and Runx2, whereas compound C or dominant negative AMPK inhibited these effects. Transient transfection studies also showed that metformin increased the BRE-Luc and Runx2-Luc activities, which were inhibited by DN-AMPK or compound C. Down-regulation of Dlx5 expression by siRNA suppressed metformin-induced Runx2 expression. These results suggest that the activation of AMPK stimulates osteoblast differentiation via the regulation of Smad1/5/8-Dlx5-Runx2 signaling pathway.
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Affiliation(s)
- Won Gu Jang
- Department of Pharmacology and Dental Therapeutics and BK21, School of Dentistry, Chonnam National University, Gwangju 500-757, Republic of Korea.
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119
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Baek JA, Lan Y, Liu H, Maltby KM, Mishina Y, Jiang R. Bmpr1a signaling plays critical roles in palatal shelf growth and palatal bone formation. Dev Biol 2010; 350:520-31. [PMID: 21185278 DOI: 10.1016/j.ydbio.2010.12.028] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/02/2010] [Accepted: 12/16/2010] [Indexed: 12/27/2022]
Abstract
Cleft palate, including submucous cleft palate, is among the most common birth defects in humans. While overt cleft palate results from defects in growth or fusion of the developing palatal shelves, submucous cleft palate is characterized by defects in palatal bones. In this report, we show that the Bmpr1a gene, encoding a type I receptor for bone morphogenetic proteins (Bmp), is preferentially expressed in the primary palate and anterior secondary palate during palatal outgrowth. Following palatal fusion, Bmpr1a mRNA expression was upregulated in the condensed mesenchyme progenitors of palatal bone. Tissue-specific inactivation of Bmpr1a in the developing palatal mesenchyme in mice caused reduced cell proliferation in the primary and anterior secondary palate, resulting in partial cleft of the anterior palate at birth. Expression of Msx1 and Fgf10 was downregulated in the anterior palate mesenchyme and expression of Shh was downregulated in the anterior palatal epithelium in the Bmpr1a conditional mutant embryos, indicating that Bmp signaling regulates mesenchymal-epithelial interactions during palatal outgrowth. In addition, formation of the palatal processes of the maxilla was blocked while formation of the palatal processes of the palatine was significantly delayed, resulting in submucous cleft of the hard palate in the mutant mice. Our data indicate that Bmp signaling plays critical roles in the regulation of palatal mesenchyme condensation and osteoblast differentiation during palatal bone formation.
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Affiliation(s)
- Jin-A Baek
- Center for Oral Biology, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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120
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Fairbridge NA, Dawe CE, Niri FH, Kooistra MK, King-Jones K, McDermid HE. Cecr2 mutations causing exencephaly trigger misregulation of mesenchymal/ectodermal transcription factors. ACTA ACUST UNITED AC 2010; 88:619-25. [PMID: 20589882 DOI: 10.1002/bdra.20695] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Over 200 mouse genes are associated with neural tube defects (NTDs), including Cecr2, the bromodomain-containing subunit of the CERF chromatin remodeling complex. METHODS Gene-trap mutation Cecr2(Gt45Bic) results in 74% exencephaly (equivalent of human anencephaly) on the BALB/c strain. Gene expression altered during cranial neural tube closure by the Cecr2 mutation was identified through microarray analysis of 11-14 somites stage Cecr2(Gt45Bic)embryos. RESULTS Analysis of Affymetrix Mouse 430 2.0 chips detected 60 transcripts up-regulated and 54 transcripts down-regulated in the Cecr2(Gt45Bic) embryos (fold > 1.5, p < 0.05). The Cecr2 transcript was reduced only approximately 7- to 14-fold from normal levels, suggesting the Cecr2(Gt45Bic) is a hypomorphic mutation. We therefore generated a novel Cecr2 null allele (Cecr2 (tm1.1Hemc)). Resulting mutants displayed a stronger penetrance of exencephaly than Cecr2(Gt45Bic) in both BALB/c and FVB/N strains, in addition to midline facial clefts and forebrain encephalocele in the FVB/N strain. The Cecr2 transcript is reduced 260-fold in the Cecr2(tm1.1Hemc) line. Subsequent qRT-PCR using Cecr2 (tm1.1Hemc) mutant heads confirmed downregulation of transcription factors Alx1/Cart1, Dlx5, Eya1, and Six1. CONCLUSIONS As both Alx1/Cart1 and Dlx5 mouse mutations result in exencephaly, we hypothesize that changes in expression of these mesenchymal/ectodermal transcription factors may contribute to NTDs associated with Cecr2.
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121
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Frenz DA, Liu W, Cvekl A, Xie Q, Wassef L, Quadro L, Niederreither K, Maconochie M, Shanske A. Retinoid signaling in inner ear development: A "Goldilocks" phenomenon. Am J Med Genet A 2010; 152A:2947-61. [PMID: 21108385 PMCID: PMC3057869 DOI: 10.1002/ajmg.a.33670] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Retinoic acid (RA) is a biologically active derivative of vitamin A that is indispensable for inner ear development. The normal function of RA is achieved only at optimal homeostatic concentrations, with an excess or deficiency in RA leading to inner ear dysmorphogenesis. We present an overview of the role of RA in the developing mammalian inner ear, discussing both how and when RA may act to critically control a program of inner ear development. Molecular mechanisms of otic teratogenicity involving two members of the fibroblast growth factor family, FGF3 and FGF10, and their downstream targets, Dlx5 and Dlx6, are examined under conditions of both RA excess and deficiency. We term the effect of too little or too much RA on FGF/Dlx signaling a Goldilocks phenomenon. We demonstrate that in each case (RA excess, RA deficiency), RA can directly affect FGF3/FGF10 signaling within the otic epithelium, leading to downregulated expression of these essential signaling molecules, which in turn, leads to diminution in Dlx5/Dlx6 expression. Non-cell autonomous affects of the otic epithelium subsequently occur, altering transforming growth factor-beta (TGFβ) expression in the neighboring periotic mesenchyme and serving as a putative explanation for RA-mediated otic capsule defects. We conclude that RA coordinates inner ear morphogenesis by controlling an FGF/Dlx signaling cascade, whose perturbation by deviations in local retinoid concentrations can lead to inner ear dysmorphogenesis.
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Affiliation(s)
- Dorothy A Frenz
- Department of Otorhinolaryngology Head & Neck Surgery, Albert Einstein College of Medicine, Bronx, New York, USA.
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Chung IH, Han J, Iwata J, Chai Y. Msx1 and Dlx5 function synergistically to regulate frontal bone development. Genesis 2010; 48:645-55. [PMID: 20824629 DOI: 10.1002/dvg.20671] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2010] [Revised: 08/31/2010] [Accepted: 09/01/2010] [Indexed: 11/09/2022]
Abstract
The Msx and Dlx families of homeobox proteins are important regulators for embryogenesis. Loss of Msx1 in mice results in multiple developmental defects including craniofacial malformations. Although Dlx5 is widely expressed during embryonic development, targeted null mutation of Dlx5 mainly affects the development of craniofacial bones. Msx1 and Dlx5 show overlapping expression patterns during frontal bone development. To investigate the functional significance of Msx1/Dlx5 interaction in regulating frontal bone development, we generated Msx1 and Dlx5 double null mutant mice. In Msx1(-/-) ;Dlx5(-/-) mice, the frontal bones defect was more severe than that of either Msx1(-/-) or Dlx5(-/-) mice. This aggravated frontal bone defect suggests that Msx1 and Dlx5 function synergistically to regulate osteogenesis. This synergistic effect of Msx1 and Dlx5 on the frontal bone represents a tissue specific mode of interaction of the Msx and Dlx genes. Furthermore, Dlx5 requires Msx1 for its expression in the context of frontal bone development. Our study shows that Msx1/Dlx5 interaction is crucial for osteogenic induction during frontal bone development.
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Affiliation(s)
- Il-Hyuk Chung
- Center for Craniofacial Molecular Biology, Ostrow School of Dentistry, University of Southern California, Los Angeles, California 90033, USA
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123
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Chen JR, Lazarenko OP, Wu X, Kang J, Blackburn ML, Shankar K, Badger TM, Ronis MJJ. Dietary-induced serum phenolic acids promote bone growth via p38 MAPK/β-catenin canonical Wnt signaling. J Bone Miner Res 2010; 25:2399-411. [PMID: 20499363 DOI: 10.1002/jbmr.137] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Diet and nutritional status are critical factors that influences bone development. In this report we demonstrate that a mixture of phenolic acids found in the serum of young rats fed blueberries (BB) significantly stimulated osteoblast differentiation, resulting in significantly increased bone mass. Greater bone formation in BB diet-fed animals was associated with increases in osteoblast progenitors and osteoblast differentiation and reduced osteoclastogenesis. Blockade of p38 phosphorylation eliminated effects of BB on activation of Wnt signaling in preosteoblasts. Knocking down β-catenin expression also blocked the ability of serum from BB diet-fed rats to stimulate osteoblast differentiation in vitro. Based on our in vivo and in vitro data, we propose that the underlying mechanisms of these powerful bone-promoting effects occur through β-catenin activation and the nuclear accumulation and transactivation of TCF/LEF gene transcription in bone and in osteoblasts. These results indicate stimulation of molecular events leading to osteoblast differentiation triggered by P38 MAP kinase (MAPK)/β-catenin canonical Wnt signaling results in significant increases in bone growth in young rats consuming BB-supplemented diets. Liquid chromatography/mass spectrometry (LC/MS) characterization of the serum after BB feeding revealed a mixture of simple phenolic acids that may provide a basis for developing a new treatment to increase peak bone mass and delay degenerative bone disorders such as osteoporosis.
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Affiliation(s)
- Jin-Ran Chen
- Arkansas Children's Nutrition Center, University of Arkansas for Medical Sciences, Little Rock, AR 72202, USA.
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124
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Vieux-Rochas M, Mantero S, Heude E, Barbieri O, Astigiano S, Couly G, Kurihara H, Levi G, Merlo GR. Spatio-temporal dynamics of gene expression of the Edn1-Dlx5/6 pathway during development of the lower jaw. Genesis 2010; 48:262-373. [PMID: 20333701 DOI: 10.1002/dvg.20625] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The morphogenesis of the vertebrate skull results from highly dynamic integrated processes involving the exchange of signals between the ectoderm, the endoderm, and cephalic neural crest cells (CNCCs). Before migration CNCCs are not committed to form any specific skull element, molecular signals exchanged in restricted regions of tissue interaction are crucial in providing positional identity to the CNCCs mesenchyme and activate the specific morphogenetic process of different skeletal components of the head. In particular, the endothelin-1 (Edn1)-dependent activation of Dlx5 and Dlx6 in CNCCs that colonize the first pharyngeal arch (PA1) is necessary and sufficient to specify maxillo-mandibular identity. Here, to better analyze the spatio-temporal dynamics of this process, we associate quantitative gene expression analysis with detailed examination of skeletal phenotypes resulting from combined allelic reduction of Edn1, Dlx5, and Dlx6. We show that Edn1-dependent and -independent regulatory pathways act at different developmental times in distinct regions of PA1. The Edn1-->Dlx5/6-->Hand2 pathway is already active at E9.5 during early stages of CNCCs colonization. At later stages (E10.5) the scenario is more complex: we propose a model in which PA1 is subdivided into four adjacent territories in which distinct regulations are taking place. This new developmental model may provide a conceptual framework to interpret the craniofacial malformations present in several mouse mutants and in human first arch syndromes. More in general, our findings emphasize the importance of quantitative gene expression in the fine control of morphogenetic events.
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125
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Kouwenhoven EN, van Heeringen SJ, Tena JJ, Oti M, Dutilh BE, Alonso ME, de la Calle-Mustienes E, Smeenk L, Rinne T, Parsaulian L, Bolat E, Jurgelenaite R, Huynen MA, Hoischen A, Veltman JA, Brunner HG, Roscioli T, Oates E, Wilson M, Manzanares M, Gómez-Skarmeta JL, Stunnenberg HG, Lohrum M, van Bokhoven H, Zhou H. Genome-wide profiling of p63 DNA-binding sites identifies an element that regulates gene expression during limb development in the 7q21 SHFM1 locus. PLoS Genet 2010; 6:e1001065. [PMID: 20808887 PMCID: PMC2924305 DOI: 10.1371/journal.pgen.1001065] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 07/12/2010] [Indexed: 12/04/2022] Open
Abstract
Heterozygous mutations in p63 are associated with split hand/foot malformations (SHFM), orofacial clefting, and ectodermal abnormalities. Elucidation of the p63 gene network that includes target genes and regulatory elements may reveal new genes for other malformation disorders. We performed genome-wide DNA–binding profiling by chromatin immunoprecipitation (ChIP), followed by deep sequencing (ChIP–seq) in primary human keratinocytes, and identified potential target genes and regulatory elements controlled by p63. We show that p63 binds to an enhancer element in the SHFM1 locus on chromosome 7q and that this element controls expression of DLX6 and possibly DLX5, both of which are important for limb development. A unique micro-deletion including this enhancer element, but not the DLX5/DLX6 genes, was identified in a patient with SHFM. Our study strongly indicates disruption of a non-coding cis-regulatory element located more than 250 kb from the DLX5/DLX6 genes as a novel disease mechanism in SHFM1. These data provide a proof-of-concept that the catalogue of p63 binding sites identified in this study may be of relevance to the studies of SHFM and other congenital malformations that resemble the p63-associated phenotypes. Mammalian embryonic development requires precise control of gene expression in the right place at the right time. One level of control of gene expression is through cis-regulatory elements controlled by transcription factors. Deregulation of gene expression by mutations in such cis-regulatory elements has been described in developmental disorders. Heterozygous mutations in the transcription factor p63 are found in patients with limb malformations, cleft lip/palate, and defects in skin and other epidermal appendages, through disruption of normal ectodermal development during embryogenesis. We reasoned that the identification of target genes and cis-regulatory elements controlled by p63 would provide candidate genes for defects arising from abnormally regulated ectodermal development. To test our hypothesis, we carried out a genome-wide binding site analysis and identified a large number of target genes and regulatory elements regulated by p63. We further showed that one of these regulatory elements controls expression of DLX6 and possibly DLX5 in the apical ectodermal ridge in the developing limbs. Loss of this element through a micro-deletion was associated with split hand foot malformation (SHFM1). The list of p63 binding sites provides a resource for the identification of mutations that cause ectodermal dysplasias and malformations in humans.
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MESH Headings
- Animals
- Base Sequence
- Binding Sites
- Cells, Cultured
- Child, Preschool
- Chromatin Immunoprecipitation
- Chromosomes, Human, Pair 7/genetics
- Chromosomes, Human, Pair 7/metabolism
- DNA-Binding Proteins/genetics
- DNA-Binding Proteins/metabolism
- Enhancer Elements, Genetic
- Female
- Gene Expression Regulation, Developmental
- Genome-Wide Association Study
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Humans
- Keratinocytes/metabolism
- Limb Deformities, Congenital/genetics
- Limb Deformities, Congenital/metabolism
- Male
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice
- Molecular Sequence Data
- Proteasome Endopeptidase Complex/genetics
- Proteasome Endopeptidase Complex/metabolism
- Protein Binding
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Zebrafish
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Affiliation(s)
- Evelyn N. Kouwenhoven
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Simon J. van Heeringen
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Juan J. Tena
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Martin Oti
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Bas E. Dutilh
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - M. Eva Alonso
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - Elisa de la Calle-Mustienes
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Leonie Smeenk
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Tuula Rinne
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Lilian Parsaulian
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Emine Bolat
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Rasa Jurgelenaite
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Martijn A. Huynen
- Centre for Molecular and Biomolecular Informatics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Joris A. Veltman
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Han G. Brunner
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Tony Roscioli
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - Emily Oates
- Department of Clinical Genetics, Children's Hospital at Westmead, Westmead, Australia
| | - Meredith Wilson
- Department of Clinical Genetics, Children's Hospital at Westmead, Westmead, Australia
| | - Miguel Manzanares
- Fundación Centro Nacional de Investigaciones Cardiovasculares Carlos III, Madrid, Spain
| | - José Luis Gómez-Skarmeta
- Centro Andaluz de Biología del Desarrollo, Universidad Pablo de Olavide, Consejo Superior de Investigaciones Científicas, Sevilla, Spain
| | - Hendrik G. Stunnenberg
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Marion Lohrum
- Department of Molecular Biology, Faculty of Science, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands
| | - Hans van Bokhoven
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition, and Behavior, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (HZ); (HvB)
| | - Huiqing Zhou
- Department of Human Genetics, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
- * E-mail: (HZ); (HvB)
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126
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Minoux M, Rijli FM. Molecular mechanisms of cranial neural crest cell migration and patterning in craniofacial development. Development 2010; 137:2605-21. [DOI: 10.1242/dev.040048] [Citation(s) in RCA: 329] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
During vertebrate craniofacial development, neural crest cells (NCCs) contribute much of the cartilage, bone and connective tissue that make up the developing head. Although the initial patterns of NCC segmentation and migration are conserved between species, the variety of vertebrate facial morphologies that exist indicates that a complex interplay occurs between intrinsic genetic NCC programs and extrinsic environmental signals during morphogenesis. Here, we review recent work that has begun to shed light on the molecular mechanisms that govern the spatiotemporal patterning of NCC-derived skeletal structures – advances that are central to understanding craniofacial development and its evolution.
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Affiliation(s)
- Maryline Minoux
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
- Faculté de Chirurgie Dentaire, 1, Place de l'Hôpital, 67000 Strasbourg, France
| | - Filippo M. Rijli
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
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127
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Chatterjee S, Kraus P, Lufkin T. A symphony of inner ear developmental control genes. BMC Genet 2010; 11:68. [PMID: 20637105 PMCID: PMC2915946 DOI: 10.1186/1471-2156-11-68] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Accepted: 07/16/2010] [Indexed: 01/21/2023] Open
Abstract
The inner ear is one of the most complex and detailed organs in the vertebrate body and provides us with the priceless ability to hear and perceive linear and angular acceleration (hence maintain balance). The development and morphogenesis of the inner ear from an ectodermal thickening into distinct auditory and vestibular components depends upon precise temporally and spatially coordinated gene expression patterns and well orchestrated signaling cascades within the otic vesicle and upon cellular movements and interactions with surrounding tissues. Gene loss of function analysis in mice has identified homeobox genes along with other transcription and secreted factors as crucial regulators of inner ear morphogenesis and development. While otic induction seems dependent upon fibroblast growth factors, morphogenesis of the otic vesicle into the distinct vestibular and auditory components appears to be clearly dependent upon the activities of a number of homeobox transcription factors. The Pax2 paired-homeobox gene is crucial for the specification of the ventral otic vesicle derived auditory structures and the Dlx5 and Dlx6 homeobox genes play a major role in specification of the dorsally derived vestibular structures. Some Micro RNAs have also been recently identified which play a crucial role in the inner ear formation.
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Affiliation(s)
- Sumantra Chatterjee
- Stem Cell and Developmental Biology, Genome Institute of Singapore, 60 Biopolis Street, 138672 Singapore
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128
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Iacoangeli A, Bianchi R, Tiedge H. Regulatory RNAs in brain function and disorders. Brain Res 2010; 1338:36-47. [PMID: 20307503 PMCID: PMC3524968 DOI: 10.1016/j.brainres.2010.03.042] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/10/2010] [Accepted: 03/15/2010] [Indexed: 11/17/2022]
Abstract
Regulatory RNAs are being increasingly investigated in neurons, and important roles in brain function have been revealed. Regulatory RNAs are non-protein-coding RNAs (npcRNAs) that comprise a heterogeneous group of molecules, varying in size and mechanism of action. Regulatory RNAs often exert post-transcriptional control of gene expression, resulting in gene silencing or gene expression stimulation. Here, we review evidence that regulatory RNAs are implicated in neuronal development, differentiation, and plasticity. We will also discuss npcRNA dysregulation that may be involved in pathological states of the brain such as neurodevelopmental disorders, neurodegeneration, and epilepsy.
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Affiliation(s)
- Anna Iacoangeli
- The Robert F. Furchgott Center for Neural and Behavioral Science, Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
| | - Riccardo Bianchi
- The Robert F. Furchgott Center for Neural and Behavioral Science, Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
- Program in Neural and Behavioral Science, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
| | - Henri Tiedge
- The Robert F. Furchgott Center for Neural and Behavioral Science, Department of Physiology and Pharmacology, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
- Program in Neural and Behavioral Science, State University of New York, Health Science Center at Brooklyn, 450 Clarkson Avenue, Brooklyn, New York 11203, USA
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129
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Zhang C. Transcriptional regulation of bone formation by the osteoblast-specific transcription factor Osx. J Orthop Surg Res 2010; 5:37. [PMID: 20550694 PMCID: PMC2898801 DOI: 10.1186/1749-799x-5-37] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 06/15/2010] [Indexed: 12/17/2022] Open
Abstract
Bone formation is a complex developmental process involving the differentiation of mesenchymal stem cells to osteoblasts. Osteoblast differentiation occurs through a multi-step molecular pathway regulated by different transcription factors and signaling proteins. Osx (also known as Sp7) is the only osteoblast-specific transcriptional factor identified so far which is required for osteoblast differentiation and bone formation. Osx knock-out mice lack bone completely and cartilage is normal. This opens a new window to the whole research field of bone formation. Osx inhibits Wnt pathway signaling, a possible mechanism for Osx to inhibit osteoblast proliferation. These reports demonstrate that Osx is the master gene that controls osteoblast lineage commitment and the subsequent osteoblast proliferation and differentiation. This review is to highlight recent progress in understanding the molecular mechanisms of transcriptional regulation of bone formation by Osx.
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Affiliation(s)
- Chi Zhang
- Bone Research Laboratory, Texas Scottish Rite Hospital for Children, Department of Orthopedic Surgery, University of Texas Southwestern Medical Center at Dallas, Texas, USA.
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130
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Greenblatt MB, Shim JH, Zou W, Sitara D, Schweitzer M, Hu D, Lotinun S, Sano Y, Baron R, Park JM, Arthur S, Xie M, Schneider MD, Zhai B, Gygi S, Davis R, Glimcher LH. The p38 MAPK pathway is essential for skeletogenesis and bone homeostasis in mice. J Clin Invest 2010; 120:2457-73. [PMID: 20551513 DOI: 10.1172/jci42285] [Citation(s) in RCA: 314] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Accepted: 04/28/2010] [Indexed: 01/19/2023] Open
Abstract
Nearly every extracellular ligand that has been found to play a role in regulating bone biology acts, at least in part, through MAPK pathways. Nevertheless, much remains to be learned about the contribution of MAPKs to osteoblast biology in vivo. Here we report that the p38 MAPK pathway is required for normal skeletogenesis in mice, as mice with deletion of any of the MAPK pathway member-encoding genes MAPK kinase 3 (Mkk3), Mkk6, p38a, or p38b displayed profoundly reduced bone mass secondary to defective osteoblast differentiation. Among the MAPK kinase kinase (MAP3K) family, we identified TGF-beta-activated kinase 1 (TAK1; also known as MAP3K7) as the critical activator upstream of p38 in osteoblasts. Osteoblast-specific deletion of Tak1 resulted in clavicular hypoplasia and delayed fontanelle fusion, a phenotype similar to the cleidocranial dysplasia observed in humans haploinsufficient for the transcription factor runt-related transcription factor 2 (Runx2). Mechanistic analysis revealed that the TAK1-MKK3/6-p38 MAPK axis phosphorylated Runx2, promoting its association with the coactivator CREB-binding protein (CBP), which was required to regulate osteoblast genetic programs. These findings reveal an in vivo function for p38beta and establish that MAPK signaling is essential for bone formation in vivo. These results also suggest that selective p38beta agonists may represent attractive therapeutic agents to prevent bone loss associated with osteoporosis and aging.
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Affiliation(s)
- Matthew B Greenblatt
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, and Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
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131
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Song GA, Kim HJ, Woo KM, Baek JH, Kim GS, Choi JY, Ryoo HM. Molecular consequences of the ACVR1(R206H) mutation of fibrodysplasia ossificans progressiva. J Biol Chem 2010; 285:22542-53. [PMID: 20463014 DOI: 10.1074/jbc.m109.094557] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Fibrodysplasia ossificans progressiva (FOP), a rare genetic and catastrophic disorder characterized by progressive heterotopic ossification, is caused by a point mutation, c.617G>A; p.R206H, in the activin A receptor type 1 (ACVR1) gene, one of the bone morphogenetic protein type I receptors (BMPR-Is). Although altered BMP signaling has been suggested to explain the pathogenesis, the molecular consequences of this mutation are still elusive. Here we studied the impact of ACVR1 R206H mutation on BMP signaling and its downstream signaling cascades in murine myogenic C2C12 cells and HEK 293 cells. We found that ACVR1 was the most abundant of the BMPR-Is expressed in mesenchymal cells but its contribution to osteogenic BMP signal transduction was minor. The R206H mutant caused weak activation of the BMP signaling pathway, unlike the Q207D mutant, a strong and constitutively active form. The R206H mutant showed a decreased binding affinity for FKBP1A/FKBP12, a known safeguard molecule against the leakage of transforming growth factor (TGF)-beta or BMP signaling. The decreased binding affinity of FKBP1A to the mutant R206H ACVR1 resulted in leaky activation of the BMP signal, and moreover, it decreased steady-state R206H ACVR1 protein levels. Interestingly, while WT ACVR1 and FKBP1A were broadly distributed in plasma membrane and cytoplasm without BMP-2 stimulation and then localized in plasma membrane on BMP-2 stimulation, R206H ACVR1 and FKBP1A were mainly distributed in plasma membrane regardless of BMP-2 stimulation. The impaired binding to FKBP1A and an altered subcellular distribution by R206H ACVR1 mutation may result in mild activation of osteogenic BMP-signaling in extraskeletal sites such as muscle, which eventually lead to delayed and progressive ectopic bone formation in FOP patients.
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Affiliation(s)
- Gin-Ah Song
- Department of Molecular Genetics, BK21 Program, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749, Korea
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132
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Mikami Y, Asano M, Honda MJ, Takagi M. Bone morphogenetic protein 2 and dexamethasone synergistically increase alkaline phosphatase levels through JAK/STAT signaling in C3H10T1/2 cells. J Cell Physiol 2010; 223:123-33. [PMID: 20039267 DOI: 10.1002/jcp.22017] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Alkaline phosphatase (ALP) is generally believed to be a faithful marker of osteoblast differentiation, and its expression is induced by bone morphogenetic protein-2 (BMP-2) and dexamethasone (Dex). However, the effects of combined administration of BMP-2 and Dex on ALP transcription have not been extensively examined. In this study, we found that BMP-2 and Dex synergistically increase ALP levels in mouse C3H10T1/2 pluripotent stem cells. However, switching from one inducer to the other, by adding BMP-2 or Dex to cell cultures at different times, was no more effective than continuous treatment with either inducer alone. A significant induction of ALP mRNA expression was observed only in cells continuously treated with both inducers. This result suggests that both BMP-2 and Dex may act in the same pathway or at the same stage of differentiation. A luciferase assay using ALP promoter deletion constructs showed that a region of the promoter containing a putative signal transducer and activator of transcription 3 (STAT3) response element (SRE) responds to treatment with a combination of BMP-2 and Dex. Furthermore, a ChIP assay indicated that STAT3 bound to the SRE. In addition, a STAT3 siRNA suppressed the synergistic effect of BMP-2 and Dex on ALP levels. These results indicate that STAT3 may play an important role in regulating ALP expression. To our knowledge, this is the first time that STAT3 has been implicated in the regulation of ALP expression by BMP-2 and Dex. These findings raise the possibility of developing new strategies for the enhancement of bone formation using a combination of BMPs and Dex.
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Affiliation(s)
- Yoshikazu Mikami
- 1st Department of Anatomy, Nihon University School of Dentistry, Chiyoda-ku, Tokyo, Japan.
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133
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Brown KK, Reiss JA, Crow K, Ferguson HL, Kelly C, Fritzsch B, Morton CC. Deletion of an enhancer near DLX5 and DLX6 in a family with hearing loss, craniofacial defects, and an inv(7)(q21.3q35). Hum Genet 2010; 127:19-31. [PMID: 19707792 DOI: 10.1007/s00439-009-0736-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2009] [Accepted: 08/16/2009] [Indexed: 11/29/2022]
Abstract
Precisely regulated temporal and spatial patterns of gene expression are essential for proper human development. Cis-acting regulatory elements, some located at large distances from their corresponding genes, play a critical role in transcriptional control of key developmental genes and disruption of these regulatory elements can lead to disease. We report a three generation family with five affected members, all of whom have hearing loss, craniofacial defects, and a paracentric inversion of the long arm of chromosome 7, inv(7)(q21.3q35). High resolution mapping of the inversion showed that the 7q21.3 breakpoint is located 65 and 80 kb centromeric of DLX6 and DLX5, respectively. Further analysis revealed a 5,115 bp deletion at the 7q21.3 breakpoint. While the breakpoint does not disrupt either DLX5 or DLX6, the syndrome present in the family is similar to that observed in Dlx5 knockout mice and includes a subset of the features observed in individuals with DLX5 and DLX6 deletions, implicating dysregulation of DLX5 and DLX6 in the family's phenotype. Bioinformatic analysis indicates that the 5,115 bp deletion at the 7q21.3 breakpoint could contain regulatory elements necessary for DLX5 and DLX6 expression. Using a transgenic mouse reporter assay, we show that the deleted sequence can drive expression in the inner ear and developing bones of E12.5 embryos. Consequently, the observed familial syndrome is likely caused by dysregulation of DLX5 and/or DLX6 in specific tissues due to deletion of an enhancer and possibly separation from other regulatory elements by the chromosomal inversion.
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Affiliation(s)
- Kerry K Brown
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
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134
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Human-specific transcriptional regulation of CNS development genes by FOXP2. Nature 2010; 462:213-7. [PMID: 19907493 PMCID: PMC2778075 DOI: 10.1038/nature08549] [Citation(s) in RCA: 238] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2009] [Accepted: 10/01/2009] [Indexed: 02/07/2023]
Abstract
The signaling pathways orchestrating both the evolution and development of language in the human brain remain unknown. To date, the transcription factor FOXP2 (forkhead box P2) is the only gene implicated in Mendelian forms of human speech and language dysfunction1,2,3. It has been proposed, that the amino acid composition in the human variant of FOXP2 has undergone accelerated evolution, and this change occurred around the time of language emergence in humans4,5. However, this remains controversial, and whether the acquisition of these amino acids in human FOXP2 has any functional consequence in human neurons remains untested. Here, we demonstrate that these two amino acids alter FOXP2 function by conferring differential transcriptional regulation in vitro. We extend these observations in vivo to human and chimpanzee brain, and use network analysis to identify novel relationships among the differentially expressed genes. These data provide experimental support for the functional relevance of changes in FOXP2 that occur on the human lineage, highlighting specific pathways with direct consequences for human brain development and disease. Since FOXP2 has an important role in speech and language in humans, the identified targets may have a critical function in the development and evolution of language circuitry in humans.
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135
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Schlosser G. Making senses development of vertebrate cranial placodes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 283:129-234. [PMID: 20801420 DOI: 10.1016/s1937-6448(10)83004-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Cranial placodes (which include the adenohypophyseal, olfactory, lens, otic, lateral line, profundal/trigeminal, and epibranchial placodes) give rise to many sense organs and ganglia of the vertebrate head. Recent evidence suggests that all cranial placodes may be developmentally related structures, which originate from a common panplacodal primordium at neural plate stages and use similar regulatory mechanisms to control developmental processes shared between different placodes such as neurogenesis and morphogenetic movements. After providing a brief overview of placodal diversity, the present review summarizes current evidence for the existence of a panplacodal primordium and discusses the central role of transcription factors Six1 and Eya1 in the regulation of processes shared between different placodes. Upstream signaling events and transcription factors involved in early embryonic induction and specification of the panplacodal primordium are discussed next. I then review how individual placodes arise from the panplacodal primordium and present a model of multistep placode induction. Finally, I briefly summarize recent advances concerning how placodal neurons and sensory cells are specified, and how morphogenesis of placodes (including delamination and migration of placode-derived cells and invagination) is controlled.
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Affiliation(s)
- Gerhard Schlosser
- Zoology, School of Natural Sciences & Martin Ryan Institute, National University of Ireland, Galway, Ireland
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136
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Kanamoto T, Mizuhashi K, Terada K, Minami T, Yoshikawa H, Furukawa T. Isolation and characterization of a novel plasma membrane protein, osteoblast induction factor (obif), associated with osteoblast differentiation. BMC DEVELOPMENTAL BIOLOGY 2009; 9:70. [PMID: 20025746 PMCID: PMC2805627 DOI: 10.1186/1471-213x-9-70] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 12/21/2009] [Indexed: 01/09/2023]
Abstract
BACKGROUND While several cell types are known to contribute to bone formation, the major player is a common bone matrix-secreting cell type, the osteoblast. Chondrocytes, which plays critical roles at several stages of endochondral ossification, and osteoblasts are derived from common precursors, and both intrinsic cues and signals from extrinsic cues play critical roles in the lineage decision of these cell types. Several studies have shown that cell fate commitment within the osteoblast lineage requires sequential, stage-specific signaling to promote osteoblastic differentiation programs. In osteoblastic differentiation, the functional mechanisms of transcriptional regulators have been well elucidated, however the exact roles of extrinsic molecules in osteoblastic differentiation are less clear. RESULTS We identify a novel gene, obif (osteoblast induction factor), encoding a transmembrane protein that is predominantly expressed in osteoblasts. During mouse development, obif is initially observed in the limb bud in a complementary pattern to Sox9 expression. Later in development, obif is highly expressed in osteoblasts at the stage of endochondral ossification. In cell line models, obif is up-regulated during osteoblastic differentiation. Exogenous obif expression stimulates osteoblastic differentiation and obif knockdown inhibits osteoblastic differentiation in preosteblastic MC3T3-E1 cells. In addition, the extracellular domain of obif protein exhibits functions similar to the full-length obif protein in induction of MC3T3-E1 differentiation. CONCLUSIONS Our results suggest that obif plays a role in osteoblastic differentiation by acting as a ligand.
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Affiliation(s)
- Takashi Kanamoto
- Department of Developmental Biology, Osaka Bioscience Institute, 6-2-4 Furuedai, Suita, Osaka 565-0874, Japan.
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137
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Paxton CN, Bleyl SB, Chapman SC, Schoenwolf GC. Identification of differentially expressed genes in early inner ear development. Gene Expr Patterns 2009; 10:31-43. [PMID: 19913109 DOI: 10.1016/j.gep.2009.11.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Revised: 10/30/2009] [Accepted: 11/05/2009] [Indexed: 01/06/2023]
Abstract
To understand the etiology of congenital hearing loss, a comprehensive understanding of the molecular genetic mechanisms underlying normal ear development is required. We are identifying genes involved in otogenesis, with the longer term goal of studying their mechanisms of action, leading to inner ear induction and patterning. Using Agilent microarrays, we compared the differential expression of a test domain (which consisted of the pre-otic placodal ectoderm with the adjacent hindbrain ectoderm and the underlying mesendodermal tissues) with a rostral control domain (which included tissue that is competent, but not specified, to express inner ear markers in explant assays). We identified 1261 transcripts differentially expressed between the two domains at a 2-fold or greater change: 463 were upregulated and 798 were downregulated in the test domain. We validated the differential expression of several signaling molecules and transcription factors identified in this array using in situ hybridization. Furthermore, the expression patterns of the validated group of genes from the test domain were explored in detail to determine how the timing of their expression relates to specific events of otic induction and development. In conclusion, we identified a number of novel candidate genes for otic placode induction.
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Affiliation(s)
- Christian N Paxton
- University of Utah, Dept. of Neurobiology and Anatomy, Salt Lake City, UT 84132-3401, USA
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138
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Deng M, Pan L, Xie X, Gan L. Requirement for Lmo4 in the vestibular morphogenesis of mouse inner ear. Dev Biol 2009; 338:38-49. [PMID: 19913004 DOI: 10.1016/j.ydbio.2009.11.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2008] [Revised: 11/04/2009] [Accepted: 11/04/2009] [Indexed: 02/02/2023]
Abstract
During development, compartmentalization of an early embryonic structure produces blocks of cells with distinct properties and developmental potentials. The auditory and vestibular components of vertebrate inner ears are derived from defined compartments within the otocyst during embryogenesis. The vestibular apparatus, including three semicircular canals, saccule, utricle, and their associated sensory organs, detects angular and linear acceleration of the head and relays the information through vestibular neurons to vestibular nuclei in the brainstem. How the early developmental events manifest vestibular structures at the molecular level is largely unknown. Here, we show that LMO4, a LIM-domain-only transcriptional regulator, is required for the formation of semicircular canals and their associated sensory cristae. Targeted disruption of Lmo4 resulted in the dysmorphogenesis of the vestibule and in the absence of three semicircular canals, anterior and posterior cristae. In Lmo4-null otocysts, canal outpouches failed to form and cell proliferation was reduced in the dorsolateral region. Expression analysis of the known otic markers showed that Lmo4 is essential for the normal expression of Bmp4, Fgf10, Msx1, Isl1, Gata3, and Dlx5 in the dorsolateral domain of the otocyst, whereas the initial compartmentalization of the otocyst remains unaffected. Our results demonstrate that Lmo4 controls the development of the dorsolateral otocyst into semicircular canals and cristae through two distinct mechanisms: regulating the expression of otic specific genes and stimulating the proliferation of the dorsolateral part of the otocyst.
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Affiliation(s)
- Min Deng
- University of Rochester Flaum Eye Institute, University of Rochester, Rochester, NY 14642, USA
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139
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Hwang CH, Simeone A, Lai E, Wu DK. Foxg1is required for proper separation and formation of sensory cristae during inner ear development. Dev Dyn 2009; 238:2725-34. [PMID: 19842177 DOI: 10.1002/dvdy.22111] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Chan Ho Hwang
- Lab of Molecular Biology, National Institute on Deafness and Other Communication Disorders, Rockville, Maryland 20850, USA
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140
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Samee N, Geoffroy V, Marty C, Schiltz C, Vieux-Rochas M, Clément-Lacroix P, Belleville C, Levi G, de Vernejoul MC. Increased bone resorption and osteopenia in Dlx5 heterozygous mice. J Cell Biochem 2009; 107:865-72. [PMID: 19415689 DOI: 10.1002/jcb.22188] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Distal-less (Dlx) homeobox transcription factors play a central role in the control of osteogenesis. In particular, Dlx5 regulates osteoblasts/osteoclasts coupling during perinatal bone formation. We analyze here the effect of Dlx5 allelic reduction in the control of bone remodeling. We first show that Dlx5 expression persists during postnatal bone development. We then compare the skeletal phenotype of 10- and 20-week-old Dlx5(+/-) mice to that of wild-type (WT) littermates. Dlx5(+/-) male mice exhibit lower bone mineral density (BMD) at both ages while only 20-week-old females are affected. microCT analyses reveal a reduction in cortical thickness of femoral midshafts in Dlx5(+/-) mice. Histomorphometry on distal femora shows no changes in trabecular structure and confirms a reduction in Dlx5(+/-) cortical thickness. The cortical decrease of 10-week-old mice does not derive from a reduction in periosteal bone apposition, but results from increased bone resorption with a significantly higher number of endosteal osteoclasts per bone surface and a larger marrow diameter. Urinary level of deoxypyridinoline is also higher in heterozygous mice confirming an increase in bone resorption activity. Our findings might be relevant for understanding complex, multifactorial diseases such as osteoporosis in which quantitative deregulation of gene expression leads to disruption of bone homeostasis.
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Affiliation(s)
- Nadeem Samee
- INSERM U606, Hôpital Lariboisière, 2, rue Ambroise-Paré, 75475 Paris Cedex 10, France
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141
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Szeto IYY, Leung KKH, Sham MH, Cheah KSE. Utility of HoxB2 enhancer-mediated Cre activity for functional studies in the developing inner ear. Genesis 2009; 47:361-5. [PMID: 19370753 DOI: 10.1002/dvg.20507] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The rhombomere 4(r4)-restricted expression of the mouse Hoxb2 gene is regulated by a 1.4-kb enhancer-containing fragment. Here, we showthat transgenic mouse lines expressing cre driven by this fragment (B2-r4-Cre), activated the R26R Cre reporter in rhombomere 4 and the second branchial arch, the epithelium of the first branchial arch, apical ectodermal ridge of the limb buds and the tail region. Of particular interest is Cre activity in the developing inner ear. Cre activity was found in the preotic field and otic placode at E8.5 and otocyst at E9.5-E12.5, in the cochleovestibular and facio-acoustic ganglia at E10.5 and the vestibular and spiral ganglia and all the otic epithelia derived from the otocyst at E15.5 and P0. Our data suggest that the B2-r4-Cre transgenic mice provide an important tool for conditional gene manipulation and lineage tracing in the inner ear. In combination with other transgenic lines expressing cre exclusively in the otic vesicle, the relative contributions of the hindbrain, periotic mesenchyme and otic epithelium in otic development can be dissected.
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Affiliation(s)
- Irene Y Y Szeto
- Department of Biochemistry and Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
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142
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Tgfbr2 is required for development of the skull vault. Dev Biol 2009; 334:481-90. [PMID: 19699732 DOI: 10.1016/j.ydbio.2009.08.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 08/07/2009] [Accepted: 08/17/2009] [Indexed: 12/26/2022]
Abstract
Transforming growth factor beta (TGFbeta) is known to play important roles in multiple developmental processes. One of the main functions is in skeletal development. Our previous studies demonstrated that loss of Tgfbr2 in Prx1Cre-expressing limb mesenchyme results in defects in the long bones and joints of mice. Here we show that loss of Tgfbr2 also results in defects in the development of the skull vault indicating Tgfbr2 has a critical role in intramembranous bone formation as well as endochondral bone formation. Mutant mice did not survive after birth and demonstrated an open skull. The first signs of skull defects were observed at E14.5 day. Prx1Cre(+)/Tgfbr2(f/f) embryos showed significantly reduced cell proliferation in the developing mesenchyme of the skull by E14.5 day without any detectable alteration in apoptosis suggesting that reduced cell proliferation in Prx1Cre(+)/Tgfbr2(f/f) embryos was at least partially responsible for the defects observed. Immunofluorescent staining showed a significant reduction in the expression of Runx2/Cbfa1 and Osterix/Sp7 in Prx1Cre(+)/Tgfbr2(f/f) embryos suggesting that osteoblast differentiation was also altered in Prx1Cre(+)/Tgfbr2(f/f) embryos. To distinguish between the effects of losing Tgfbr2 on mesenchymal proliferation versus osteoblast differentiation, osteoprogenitor cells from the skulls of Tgfbr2(f/f) embryos were cultured under conditions of high cell density and Tgfbr2 was deleted from the cells using Adeno-Cre virus. RT-PCR analysis showed that the mRNA level of Runx2 and Osterix as well as Dlx5 and Msx2 were down-regulated in Tgfbr2-deleted cultures compared to control cultures indicating that Tgfbr2 regulates osteoblast differentiation independent of regulating proliferation. Together, these results suggest that Tgfbr2 is required for normal development of the skull.
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143
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Muneoka K, Allan CH, Yang X, Lee J, Han M. Mammalian regeneration and regenerative medicine. ACTA ACUST UNITED AC 2008; 84:265-80. [DOI: 10.1002/bdrc.20137] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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144
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Mikami Y, Somei M, Takagi M. A New Synthetic Compound, SST-VEDI-1, Inhibits Osteoblast Differentiation with a Down-Regulation of the Osterix Expression. J Biochem 2008; 145:239-47. [DOI: 10.1093/jb/mvn164] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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145
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Esterberg R, Fritz A. dlx3b/4b are required for the formation of the preplacodal region and otic placode through local modulation of BMP activity. Dev Biol 2008; 325:189-99. [PMID: 19007769 DOI: 10.1016/j.ydbio.2008.10.017] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 09/19/2008] [Accepted: 10/13/2008] [Indexed: 12/20/2022]
Abstract
The vertebrate inner ear arises from the otic placode, a transient thickening of ectodermal epithelium adjacent to neural crest domains in the presumptive head. During late gastrulation, cells fated to comprise the inner ear are part of a domain in cranial ectoderm that contain precursors of all sensory placodes, termed the preplacodal region (PPR). The combination of low levels of BMP activity coupled with high levels of FGF signaling are required to establish the PPR through induction of members of the six/eya/dach, iro, and dlx families of transcription factors. The zebrafish dlx3b/4b transcription factors are expressed at the neural plate border where they play partially redundant roles in the specification of the PPR, otic and olfactory placodes. We demonstrate that dlx3b/4b assist in establishing the PPR through the transcriptional regulation of the BMP antagonist cv2. Morpholino-mediated knockdown of Dlx3b/4b results in loss of cv2 expression in the PPR and a transient increase in Bmp4 activity that lasts throughout early somitogenesis. Through the cv2-mediated inhibition of BMP activity, dlx3b/4b create an environment where FGF activity is favorable for PPR and otic marker expression. Our results provide insight into the mechanisms of PPR specification as well as the role of dlx3b/4b function in PPR and otic placode induction.
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146
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Bear M, Butcher M, Shaughnessy SG. Oxidized low-density lipoprotein acts synergistically with beta-glycerophosphate to induce osteoblast differentiation in primary cultures of vascular smooth muscle cells. J Cell Biochem 2008; 105:185-93. [PMID: 18461557 DOI: 10.1002/jcb.21812] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Previous studies have localized osteoblast specific markers to sites of calcified atherosclerotic lesions. We therefore decided to use an established in vitro model of vascular calcification in order to confirm earlier reports of oxidized low-density lipoprotein (oxLDL) promoting the osteogenic differentiation of vascular smooth muscle cells. Treatment of primary bovine aortic smooth muscle cells (BASMCs) with beta-glycerophosphate was found to induce a time-dependent increase in osteoblast differentiation. In contrast, no effect was seen when BASMCs were cultured in the presence of oxLDL alone. However, when the BASMCs were cultured in the presence of both beta-glycerophosphate and oxLDL, beta-glycerophosphate's ability to induce osteoblast differentiation was significantly enhanced. In an attempt to resolve the mechanism by which this effect was occurring, we examined the effect of beta-glycerophosphate and oxLDL on several pathways known to be critical to the differentiation of osteoblasts. Surprisingly, beta-glycerophosphate alone was found to enhance Osterix (Osx) expression by inducing both Smad 1/5/8 activation and Runx2 expression. In contrast, oxLDL did not affect either Smad 1/5/8 activation or Runx2 activation but rather, it enhanced both beta-glycerophosphate-induced Osx expression and osteoblast differentiation in an extracellular signal-regulated kinase 1 and 2 (Erk 1 and 2) -dependent manner. When taken together, these findings suggest a plausible mechanism by which oxLDL may promote osteogenic differentiation and vascular calcification in vivo. J. Cell. Biochem. 105: 185-193, 2008. (c) 2008 Wiley-Liss, Inc.
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Affiliation(s)
- Mackenzie Bear
- Department of Pathology and Molecular Medicine, McMaster University and the Henderson Research Centre, Hamilton, Ontario, Canada
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147
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Sasaki A, Hinck L, Watanabe K. RumMAGE-D the Members: Structure and Function of a New Adaptor Family of MAGE-D Proteins. J Recept Signal Transduct Res 2008; 25:181-98. [PMID: 16194933 DOI: 10.1080/10799890500210511] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
MAGE genes were first described as cancer-testis antigens, which are silenced in normal adult tissues but aberrantly expressed in tumor cells. The short peptides, derived from the degradation of MAGE transcripts, are the source of antigens that cause tumor rejection reactions when presented in the context of major histocompatibility complex. The recent discovery of a subset of genes that contain the structurally conserved MAGE homology domain (MHD) has accelerated the investigation into the normal function of MAGE genes. This new type of MAGE gene is normally expressed in embryonal and adult tissue, especially the brain. MAGE-D1, also known as NRAGE or Dlxin-1, functions as an adaptor protein that mediates multiple signaling pathways, including NGFR (p75NTR) and UNC5H1-induced apoptosis and Dlx/Msx-mediated transcription. Loss of a different MAGE family member, Necdin, which works as a cell cycle regulator, may play a role in the pathogenesis of Prader-Willi syndrome, a neurobehavioral disorder. In this article, the authors discuss recent findings concerning the structure and function of new MAGE genes, primarily focusing on MAGE-D1. Because some MAGE-D subfamily proteins share significant homology within the MHD, these recent discoveries on MAGE-D1 may give insight into the function of other MAGE-D proteins.
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Affiliation(s)
- Aya Sasaki
- Division of the Clinical Pathology, Sapporo Medical University Hospital, Hokkaido, Japan
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148
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Lézot F, Thomas B, Greene SR, Hotton D, Yuan ZA, Castaneda B, Bolaños A, Depew M, Sharpe P, Gibson CW, Berdal A. Physiological implications of DLX homeoproteins in enamel formation. J Cell Physiol 2008; 216:688-97. [PMID: 18366088 DOI: 10.1002/jcp.21448] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Tooth development is a complex process including successive stages of initiation, morphogenesis, and histogenesis. The role of the Dlx family of homeobox genes during the early stages of tooth development has been widely analyzed, while little data has been reported on their role in dental histogenesis. The expression pattern of Dlx2 has been described in the mouse incisor; an inverse linear relationship exists between the level of Dlx2 expression and enamel thickness, suggesting a role for Dlx2 in regulation of ameloblast differentiation and activity. In vitro data have revealed that DLX homeoproteins are able to regulate the expression of matrix proteins such as osteocalcin. The aim of the present study was to analyze the expression and function of Dlx genes during amelogenesis. Analysis of Dlx2/LacZ transgenic reporter mice, Dlx2 and Dlx1/Dlx2 null mutant mice, identified spatial variations in Dlx2 expression within molar tooth germs and suggests a role for Dlx2 in the organization of preameloblastic cells as a palisade in the labial region of molars. Later, during the secretory and maturation stages of amelogenesis, the expression pattern in molars was found to be similar to that described in incisors. The expression patterns of the other Dlx genes were examined in incisors and compared to Dlx2. Within the ameloblasts Dlx3 and Dlx6 are expressed constantly throughout presecretory, secretory, and maturation stages; during the secretory phase when Dlx2 is transitorily switched off, Dlx1 expression is upregulated. These data suggest a role for DLX homeoproteins in the morphological control of enamel. Sequence analysis of the amelogenin gene promoter revealed five potential responsive elements for DLX proteins that are shown to be functional for DLX2. Regulation of amelogenin in ameloblasts may be one method by which DLX homeoproteins may control enamel formation. To conclude, this study establishes supplementary functions of Dlx family members during tooth development: the participation in establishment of dental epithelial functional organization and the control of enamel morphogenesis via regulation of amelogenin expression.
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149
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Samee N, Geoffroy V, Marty C, Schiltz C, Vieux-Rochas M, Levi G, de Vernejoul MC. Dlx5, a positive regulator of osteoblastogenesis, is essential for osteoblast-osteoclast coupling. THE AMERICAN JOURNAL OF PATHOLOGY 2008; 173:773-80. [PMID: 18669617 DOI: 10.2353/ajpath.2008.080243] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The homeodomain protein Dlx5 is an activator of Runx2 (a key regulator of osteogenesis) and is thought to be an important regulator of bone formation. At present, however, the perinatal lethality of Dlx5-null mice has hampered the elucidation of its function in osteogenesis. Here we provide the first analysis of the effects of Dlx5 inactivation on bone development. Femurs of Dlx5-null mouse embryos at the end of gestation exhibit a reduction in both total and trabecular bone volume associated with increased trabecular separation and reduced trabecular number. These parameters are often associated with pathological conditions characterized by reduced osteoblast activity and increased bone resorption. Dlx5(-/-) osteoblasts in culture display reduced proliferation and differentiation rate and reduction of Runx2, Osx, Osteocalcin and Bone Sialoprotein expression. In addition to impaired osteoblast function, Dlx5(-/-) femurs exhibit significant increases in osteoclast number. As Dlx5 is not expressed by osteoclasts, we suggest that its osteoblastic expression might control osteoblast/osteoclast coupling. Cultured Dlx5(-/-) osteoblasts displayed a higher RANKL/OPG ratio. Furthermore, Dlx5(-/-) osteoblasts induced a higher number of TRAP-positive multinucleated cells in normal spleen cultures with a globally increased resorption activity. These findings suggest that Dlx5 is a central regulator of bone turnover as it activates bone formation directly and bone resorption indirectly.
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Affiliation(s)
- Nadeem Samee
- INSERM U606, Hôpital Lariboisière, Paris, France
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150
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Vázquez-Echeverría C, Dominguez-Frutos E, Charnay P, Schimmang T, Pujades C. Analysis of mouse kreisler mutants reveals new roles of hindbrain-derived signals in the establishment of the otic neurogenic domain. Dev Biol 2008; 322:167-78. [PMID: 18703040 DOI: 10.1016/j.ydbio.2008.07.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/17/2008] [Accepted: 07/17/2008] [Indexed: 10/21/2022]
Abstract
The inner ear, the sensory organ responsible for hearing and balance, contains specialized sensory and non-sensory epithelia arranged in a highly complex three-dimensional structure. To achieve this complexity, a tight coordination between morphogenesis and cell fate specification is essential during otic development. Tissues surrounding the otic primordium, and more particularly the adjacent segmented hindbrain, have been implicated in specifying structures along the anteroposterior and dorsoventral axes of the inner ear. In this work we have first characterized the generation and axial specification of the otic neurogenic domain, and second, we have investigated the effects of the mutation of kreisler/MafB--a gene transiently expressed in rhombomeres 5 and 6 of the developing hindbrain--in early otic patterning and cell specification. We show that kr/kr embryos display an expansion of the otic neurogenic domain, due to defects in otic patterning. Although many reports have pointed to the role of FGF3 in otic regionalisation, we provide evidence that FGF3 is not sufficient to govern this process. Neither Krox20 nor Fgf3 mutant embryos, characterized by a downregulation or absence of Fgf3 in r5 and r6, display ectopic neuroblasts in the otic primordium. However, Fgf3-/-Fgf10-/- double mutants show a phenotype very similar to kr/kr embryos: they present ectopic neuroblasts along the AP and DV otic axes. Finally, partial rescue of the kr/kr phenotype is obtained when Fgf3 or Fgf10 are ectopically expressed in the hindbrain of kr/kr embryos. These results highlight the importance of hindbrain-derived signals in the regulation of otic neurogenesis.
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Affiliation(s)
- Citlali Vázquez-Echeverría
- Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, C/ Dr. Aiguader 88, 08003 Barcelona, Spain
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