304
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Behr B, Longaker MT, Quarto N. Differential activation of canonical Wnt signaling determines cranial sutures fate: a novel mechanism for sagittal suture craniosynostosis. Dev Biol 2010; 344:922-40. [PMID: 20547147 DOI: 10.1016/j.ydbio.2010.06.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2010] [Revised: 05/21/2010] [Accepted: 06/04/2010] [Indexed: 10/19/2022]
Abstract
Premature closure of cranial sutures, which serve as growth centers for the skull vault, result in craniosynostosis. In the mouse posterior frontal (PF) suture closes by endochondral ossification, whereas sagittal (SAG) remain patent life time, although both are neural crest tissue derived. We therefore, investigated why cranial sutures of same tissue origin adopt a different fate. We demonstrated that closure of the PF suture is tightly regulated by canonical Wnt signaling, whereas patency of the SAG suture is achieved by constantly activated canonical Wnt signaling. Importantly, the fate of PF and SAG sutures can be reversed by manipulating Wnt signaling. Continuous activation of canonical Wnt signaling in the PF suture inhibits endochondral ossification and therefore, suture closure, In contrast, inhibition of canonical Wnt signaling in the SAG suture, upon treatment with Wnt antagonists results in endochondral ossification and suture closure. Thus, inhibition of canonical Wnt signaling in the SAG suture phenocopies craniosynostosis. Moreover, mice haploinsufficient for Twist1, a target gene of canonical Wnt signaling which inhibits chondrogenesis, have sagittal craniosynostosis. We propose that regulation of canonical Wnt signaling is of crucial importance during the physiological patterning of PF and SAG sutures. Importantly, dysregulation of this pathway may lead to craniosynostosis.
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Affiliation(s)
- Björn Behr
- Children's Surgical Research Program, Department of Surgery, Division of Plastic and Reconstructive Surgery, Stanford University School of Medicine, Stanford, CA, USA
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307
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Choi YA, Lim J, Kim KM, Acharya B, Cho JY, Bae YC, Shin HI, Kim SY, Park EK. Secretome Analysis of Human BMSCs and Identification of SMOC1 as an Important ECM Protein in Osteoblast Differentiation. J Proteome Res 2010; 9:2946-56. [DOI: 10.1021/pr901110q] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Young-Ae Choi
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Jiwon Lim
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Kyung Min Kim
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Bodhraj Acharya
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Je-Yoel Cho
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Yong-Chul Bae
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Hong-In Shin
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Shin-Yoon Kim
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
| | - Eui Kyun Park
- Department of Oral Pathology, School of Dentistry, BK21, IHBR, Kyungpook National University, Daegu, Korea, Department of Oral Biochemistry, School of Dentistry, Kyungpook National University, Daegu, Korea, Department of Oral Anatomy and Neurobiology, School of Dentistry, Kyungpook National University Hospital, Daegu, Korea, and Department of Orthopaedic Surgery, Skeletal Diseases Genome Research Center, Kyungpook National University Hospital, Daegu, Korea
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313
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Deng L, Hu S, Baydoun AR, Chen J, Chen X, Cong X. Aspirin induces apoptosis in mesenchymal stem cells requiring Wnt/beta-catenin pathway. Cell Prolif 2009; 42:721-30. [PMID: 19706045 DOI: 10.1111/j.1365-2184.2009.00639.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Mesenchymal stem cells (MSC) are multipotent progenitor cells that are have found use in regenerative medicine. We have previously observed that aspirin, a widely used anti-inflammatory drug, inhibits MSC proliferation. Here we have aimed to elucidate whether aspirin induces MSC apoptosis and whether this is modulated through the Wnt/beta-catenin pathway. MATERIALS AND METHODS Apoptosis of MSCs was assessed using Hoechst 33342 dye and an Annexin V-FITC/PI Apoptosis Kit. Expression of protein and protein phosphorylation were investigated using Western blot analysis. Caspase-3 activity was detected by applying a caspase-3/CPP32 Colorimetric Assay Kit. RESULTS In these MSCs, aspirin induced morphological changes characteristic of apoptosis, cytochrome c release from mitochondria, and caspase-3 activation. Stimulating the Wnt/beta-catenin pathway by both Wnt 3a and GSK-3beta inhibitors (LiCl and SB 216763), blocked aspirin-induced apoptosis and protected mitochondrial function, as demonstrated by decreased cytochrome c release and caspase-3 activity. Aspirin initially caused a time-dependent decrease in COX-2 expression but subsequently, and unexpectedly, elevated the latter. Stimulation of COX-2 expression by aspirin was further enhanced following stimulation of the Wnt/beta-catenin pathway. Application of the COX-2 inhibitor NS-398 suppressed elevated COX-2 expression and promoted aspirin-induced apoptosis. CONCLUSION These results demonstrate that the Wnt/beta-catenin pathway is a key modulator of aspirin-induced apoptosis in MSCs by regulation of mitochrondrial/caspase-3 function. More importantly, our findings suggest that aspirin may influence MSC survival under certain conditions; therefore, it should be used with caution when considering regenerative MSC transplantation in patients with concomitant chronic inflammatory diseases such as arthritis.
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Affiliation(s)
- L Deng
- Research Center for Cardiovascular Regenerative Medicine, Ministry of Health, Cardiovascular Institute & Fu Wai Hospital, Chinese Academy of Medical Science & Peking Union Medicine College, Beijing 100037, China
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315
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Li C, Li A, Li M, Xing Y, Chen H, Hu L, Tiozzo C, Anderson S, Taketo MM, Minoo P. Stabilized beta-catenin in lung epithelial cells changes cell fate and leads to tracheal and bronchial polyposis. Dev Biol 2009; 334:97-108. [PMID: 19631635 DOI: 10.1016/j.ydbio.2009.07.021] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 06/15/2009] [Accepted: 07/09/2009] [Indexed: 01/22/2023]
Abstract
The precise mechanisms by which beta-catenin controls morphogenesis and cell differentiation remain largely unknown. Using embryonic lung development as a model, we deleted exon 3 of beta-catenin via Nkx2.1-cre in the Catnb[+/lox(ex3)] mice and studied its impact on epithelial morphogenesis. Robust selective accumulation of truncated, stabilized beta-catenin was found in Nkx2.1-cre;Catnb[+/lox(ex3)] lungs that were associated with the formation of polyp-like structures in the trachea and main-stem bronchi. Characterization of polyps suggests that accumulated beta-catenin impacts epithelial morphogenesis in at least two ways. "Intracellular" accumulation of beta-catenin blocked differentiation of spatially-appropriate airway epithelial cell types, Clara cells, ciliated cells and basal cells, and activated UCHL1, a marker for pulmonary neuroendocrine cells. There was also evidence for a "paracrine" impact of beta-catenin accumulation, potentially mediated via activation of Bmp4 that inhibited Clara and ciliated, but not basal cell differentiation. Thus, excess beta-catenin can alter cell fate determination by both direct and paracrine mechanisms.
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Affiliation(s)
- Changgong Li
- Department of Pediatrics, Women's and Children's Hospital, USC Keck School of Medicine, Los Angeles, CA 90033, USA.
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317
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Hsu F, Schwarz S, Mougous JD. TagR promotes PpkA-catalysed type VI secretion activation in Pseudomonas aeruginosa. Mol Microbiol 2009; 72:1111-25. [PMID: 19400797 DOI: 10.1111/j.1365-2958.2009.06701.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Type VI secretion systems (T6SSs) contribute to interactions of bacterial pathogens and symbionts with their hosts. Previously, we showed that Pseudomonas aeruginosa T6S is posttranslationally activated upon phosphorylation of Fha1, an FHA domain protein, by PpkA, a membrane-spanning threonine kinase. Herein, additional structural, enzymatic and genetic requirements for PpkA-catalysed T6SS activation are identified. We found that PpkA plays an essential structural role in the T6SS, and that this role is intimately linked to its ability to promote secretion and phosphorylate Fha1. Protein localization and protein-protein interaction studies show that a complex containing Fha1 and the T6S ATPase, ClpV1 is recruited to the T6S apparatus in a phosphorylation-dependent manner. The mechanism of PpkA activation was also investigated. We identified critical PpkA autophosphorylation sites and showed that small molecule-induced dimerization of the extracellular domains of PpkA is sufficient to activate the T6SS. Finally, we discovered TagR, a component of the T6S posttranslational regulatory pathway that functions upstream of PpkA to promote kinase activity. We present a model whereby an unknown cue causes dimerization of the extracellular domains of PpkA, leading to its autophosphorylation, recruitment of the Fha1-ClpV1 complex, phosphorylation of Fha1, and T6SS activation. Our findings should facilitate approaches for identifying physiological activators of T6S.
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Affiliation(s)
- FoSheng Hsu
- Department of Microbiology, University of Washington, Seattle, WA 98195, USA
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