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Mohan M, Mannan A, Singh TG. Therapeutic implication of Sonic Hedgehog as a potential modulator in ischemic injury. Pharmacol Rep 2023:10.1007/s43440-023-00505-0. [PMID: 37347388 DOI: 10.1007/s43440-023-00505-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 06/05/2023] [Accepted: 06/07/2023] [Indexed: 06/23/2023]
Abstract
Sonic Hedgehog (SHh) is a homology protein that is involved in the modeling and development of embryonic tissues. As SHh plays both protective and harmful roles in ischemia, any disruption in the transduction and regulation of the SHh signaling pathway causes ischemia to worsen. The SHh signal activation occurs when SHh binds to the receptor complex of Ptc-mediated Smoothened (Smo) (Ptc-smo), which initiates the downstream signaling cascade. This article will shed light on how pharmacological modifications to the SHh signaling pathway transduction mechanism alter ischemic conditions via canonical and non-canonical pathways by activating certain downstream signaling cascades with respect to protein kinase pathways, angiogenic cytokines, inflammatory mediators, oxidative parameters, and apoptotic pathways. The canonical pathway includes direct activation of interleukins (ILs), angiogenic cytokines like hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and hypoxia-inducible factor alpha (HIF-), which modulate ischemia. The non-canonical pathway includes indirect activation of certain pathways like mTOR, PI3K/Akt, MAPK, RhoA/ROCK, Wnt/-catenin, NOTCH, Forkhead box protein (FOXF), Toll-like receptors (TLR), oxidative parameters such as GSH, SOD, and CAT, and some apoptotic parameters such as Bcl2. This review provides comprehensive insights that contribute to our knowledge of how SHh impacts the progression and outcomes of ischemic injuries.
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Affiliation(s)
- Maneesh Mohan
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, 140401, India
| | - Ashi Mannan
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, 140401, India
| | - Thakur Gurjeet Singh
- Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, 140401, India.
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2
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Sailer SA, Burkhalter MD, Philipp M. Cholesterol and Phosphoinositides in Cilia Biology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:121-142. [PMID: 36988879 DOI: 10.1007/978-3-031-21547-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Cilia are evolutionarily conserved organelles that can be found on virtually every cell. They appear as hair-like structures emanating from the cellular surface either as single or as bundles of cilia. There, they sense external stimuli and translate them into intracellular signals. Motile cilia beat for the generation of locomotion of unicellular organisms or fluid flow in certain body cavities of vertebrate organisms. Defects in cilia are detrimental and account for the development of ciliopathies, one of the fastest-growing family of afflictions. In the past decade, membrane lipids, such as cholesterol and phosphoinositides, have emerged as essential elements in both the signal transduction via cilia and the building of cilia itself. Here, we summarize the current knowledge on the impact of cholesterol and phosphoinositides on cilium biology.
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Affiliation(s)
- Steffen-Alexander Sailer
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Division of Pharmacogenomics, University Hospital Tübingen, Tübingen, Germany
| | - Martin D Burkhalter
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Division of Pharmacogenomics, University Hospital Tübingen, Tübingen, Germany
| | - Melanie Philipp
- Department of Experimental and Clinical Pharmacology and Pharmacogenomics, Division of Pharmacogenomics, University Hospital Tübingen, Tübingen, Germany.
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3
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Kaushal JB, Batra SK, Rachagani S. Hedgehog signaling and its molecular perspective with cholesterol: a comprehensive review. Cell Mol Life Sci 2022; 79:266. [PMID: 35486193 PMCID: PMC9990174 DOI: 10.1007/s00018-022-04233-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/18/2022] [Accepted: 03/07/2022] [Indexed: 02/08/2023]
Abstract
Hedgehog (Hh) signaling is evolutionarily conserved and plays an instructional role in embryonic morphogenesis, organogenesis in various animals, and the central nervous system organization. Multiple feedback mechanisms dynamically regulate this pathway in a spatiotemporal and context-dependent manner to confer differential patterns in cell fate determination. Hh signaling is complex due to canonical and non-canonical mechanisms coordinating cell-cell communication. In addition, studies have demonstrated a regulatory framework of Hh signaling and shown that cholesterol is vital for Hh ligand biogenesis, signal generation, and transduction from the cell surface to intracellular space. Studies have shown the importance of a specific cholesterol pool, termed accessible cholesterol, which serves as a second messenger, conveying signals between smoothened (Smo) and patched 1 (Ptch1) across the plasma and ciliary membranes. Remarkably, recent high-resolution structural and molecular studies shed new light on the interplay between Hh signaling and cholesterol in membrane biology. These studies elucidated novel mechanistic insight into the release and dispersal of cholesterol-anchored Hh and the basis of Hh recognition by Ptch1. Additionally, the putative model of Smo activation by cholesterol binding and/or modification and Ptch1 antagonization of Smo has been explicated. However, the coupling mechanism of Hh signaling and cholesterol offered a new regulatory principle in cell biology: how effector molecules of the Hh signal network react to and remodel cholesterol accessibility in the membrane and selectively activate Hh signaling proteins thereof. Recognizing the biological importance of cholesterol in Hh signaling activation and transduction opens the door for translational research to develop novel therapeutic strategies. This review looks in-depth at canonical and non-canonical Hh signaling and the distinct proposed model of cholesterol-mediated regulation of Hh signaling components, facilitating a more sophisticated understanding of the Hh signal network and cholesterol biology.
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Affiliation(s)
- Jyoti B Kaushal
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Fred and Pamela Buffet Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
| | - Satyanarayana Rachagani
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
- Fred and Pamela Buffet Cancer Center, Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA.
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4
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Sun MR, Steward AC, Sweet EA, Martin AA, Lipinski RJ. Developmental malformations resulting from high-dose maternal tamoxifen exposure in the mouse. PLoS One 2021; 16:e0256299. [PMID: 34403436 PMCID: PMC8370643 DOI: 10.1371/journal.pone.0256299] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/03/2021] [Indexed: 12/27/2022] Open
Abstract
Tamoxifen is an estrogen receptor (ER) ligand with widespread use in clinical and basic research settings. Beyond its application in treating ER-positive cancer, tamoxifen has been co-opted into a powerful approach for temporal-specific genetic alteration. The use of tamoxifen-inducible Cre-recombinase mouse models to examine genetic, molecular, and cellular mechanisms of development and disease is now prevalent in biomedical research. Understanding off-target effects of tamoxifen will inform its use in both clinical and basic research applications. Here, we show that prenatal tamoxifen exposure can cause structural birth defects in the mouse. Administration of a single 200 mg/kg tamoxifen dose to pregnant wildtype C57BL/6J mice at gestational day 9.75 caused cleft palate and limb malformations in the fetuses, including posterior digit duplication, reduction, or fusion. These malformations were highly penetrant and consistent across independent chemical manufacturers. As opposed to 200 mg/kg, a single dose of 50 mg/kg tamoxifen at the same developmental stage did not result in overt structural malformations. Demonstrating that prenatal tamoxifen exposure at a specific time point causes dose-dependent developmental abnormalities, these findings argue for more considerate application of tamoxifen in Cre-inducible systems and further investigation of tamoxifen’s mechanisms of action.
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Affiliation(s)
- Miranda R. Sun
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Austin C. Steward
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Emma A. Sweet
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Alexander A. Martin
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Robert J. Lipinski
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
- * E-mail:
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5
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Hedgehog/GLI Signaling Pathway: Transduction, Regulation, and Implications for Disease. Cancers (Basel) 2021; 13:cancers13143410. [PMID: 34298625 PMCID: PMC8304605 DOI: 10.3390/cancers13143410] [Citation(s) in RCA: 103] [Impact Index Per Article: 34.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 07/04/2021] [Accepted: 07/05/2021] [Indexed: 12/12/2022] Open
Abstract
Simple Summary The Hedgehog/GLI (Hh/GLI) pathway plays a major role during development and it is commonly dysregulated in many diseases, including cancer. This highly concerted series of ligands, receptors, cytoplasmic signaling molecules, transcription factors, and co-regulators is involved in regulating the biological functions controlled by this pathway. Activation of Hh/GLI in cancer is most often through a non-canonical method of activation, independent of ligand binding. This review is intended to summarize our current understanding of the Hh/GLI signaling, non-canonical mechanisms of pathway activation, its implication in disease, and the current therapeutic strategies targeting this cascade. Abstract The Hh/GLI signaling pathway was originally discovered in Drosophila as a major regulator of segment patterning in development. This pathway consists of a series of ligands (Shh, Ihh, and Dhh), transmembrane receptors (Ptch1 and Ptch2), transcription factors (GLI1–3), and signaling regulators (SMO, HHIP, SUFU, PKA, CK1, GSK3β, etc.) that work in concert to repress (Ptch1, Ptch2, SUFU, PKA, CK1, GSK3β) or activate (Shh, Ihh, Dhh, SMO, GLI1–3) the signaling cascade. Not long after the initial discovery, dysregulation of the Hh/GLI signaling pathway was implicated in human disease. Activation of this signaling pathway is observed in many types of cancer, including basal cell carcinoma, medulloblastoma, colorectal, prostate, pancreatic, and many more. Most often, the activation of the Hh/GLI pathway in cancer occurs through a ligand-independent mechanism. However, in benign disease, this activation is mostly ligand-dependent. The upstream signaling component of the receptor complex, SMO, is bypassed, and the GLI family of transcription factors can be activated regardless of ligand binding. Additional mechanisms of pathway activation exist whereby the entirety of the downstream signaling pathway is bypassed, and PTCH1 promotes cell cycle progression and prevents caspase-mediated apoptosis. Throughout this review, we summarize each component of the signaling cascade, non-canonical modes of pathway activation, and the implications in human disease, including cancer.
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Kothandapani A, Jefcoate CR, Jorgensen JS. Cholesterol Contributes to Male Sex Differentiation Through Its Developmental Role in Androgen Synthesis and Hedgehog Signaling. Endocrinology 2021; 162:6204698. [PMID: 33784378 PMCID: PMC8168945 DOI: 10.1210/endocr/bqab066] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Indexed: 12/17/2022]
Abstract
Two specialized functions of cholesterol during fetal development include serving as a precursor to androgen synthesis and supporting hedgehog (HH) signaling activity. Androgens are produced by the testes to facilitate masculinization of the fetus. Recent evidence shows that intricate interactions between the HH and androgen signaling pathways are required for optimal male sex differentiation and defects of either can cause birth anomalies indicative of 46,XY male variations of sex development (VSD). Further, perturbations in cholesterol synthesis can cause developmental defects, including VSD, that phenocopy those caused by disrupted androgen or HH signaling, highlighting the functional role of cholesterol in promoting male sex differentiation. In this review, we focus on the role of cholesterol in systemic androgen and local HH signaling events during fetal masculinization and their collective contributions to pediatric VSD.
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Affiliation(s)
- Anbarasi Kothandapani
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
- Correspondence: Anbarasi Kothandapani, PhD, Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Dr, Madison, WI 53705, USA. E-mail:
| | - Colin R Jefcoate
- Department of Cell and Regenerative Biology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, USA
| | - Joan S Jorgensen
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
- Correspondence: Joan S. Jorgensen, DVM, PhD, Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Dr, Madison, WI 53705, USA. E-mail:
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7
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Acikgoz E, Mukhtarova G, Alpay A, Avci CB, Bagca BG, Oktem G. Sonic hedgehog signaling is associated with resistance to zoledronic acid in CD133high/CD44high prostate cancer stem cells. Mol Biol Rep 2021; 48:3567-3578. [PMID: 33948856 DOI: 10.1007/s11033-021-06387-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 04/24/2021] [Indexed: 12/19/2022]
Abstract
Cancer stem cells (CSCs) are a unique population that has been linked to drug resistance and metastasis and recurrence of prostate cancer. The sonic hedgehog (SHH) signal regulates stem cells in normal prostate epithelium by affecting cell behavior, survival, proliferation, and maintenance. Aberrant SHH pathway activation leads to an unsuitable expansion of stem cell lineages in the prostate epithelium and the transformation of prostate CSCs (PCSCs). Zoledronic acid (ZOL), one of the third-generation bisphosphonates, effectively prevented bone metastasis and treated advanced prostate cancer despite androgen deprivation therapy. Despite strong evidence for the involvement of the SHH in human PCSCs survival and drug resistance, the roles of SHH in the PCSCs-related resistance to ZOL remain to be fully elucidated. The present study aimed to investigate the role of the SHH pathway in ZOL resistance of PCSCs in 2D and three 3D cell culture conditions. For this purpose, we isolated CD133high/ CD44high PCSCs using a flow cytometer. Following ZOL treatment, mRNA and protein expressions of the components of the SHH signaling pathway in PCSCs and non-CSCs were analyzed using qRT-PCR and Immunofluorescence staining, respectively. Our finding suggested that SHH signaling may be activated by different mechanisms that lead to avoidance of the inhibition effect of ZOL. Thereby, SHH pathways may be associated with the resistance to ZOL developed by prostate CSCs. Inhibition of CSCs-related SHH signaling along with ZOL treatment should be considered to achieve improvement in survival or delayed treatment failure and prevention of the CSCs-related drug resistance.
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Affiliation(s)
- Eda Acikgoz
- Department of Histology and Embryology, Faculty of Medicine, Van Yuzuncu Yil University, Van, 65080, Turkey.
| | - Gunel Mukhtarova
- Department of Medical Genetics, Ege University Medical School, İzmir, 35080, Turkey.,Department of Basic Oncology, Graduate School of Health Sciences, Ege University, Izmir, 35080, Turkey
| | - Araz Alpay
- Department of Health Bioinformatics, Graduate School of Health Sciences, Ege University, Izmir, 35080, Turkey
| | - Cigir Biray Avci
- Department of Medical Biology, Faculty of Medicine, Ege University, Izmir, 35080, Turkey
| | - Bakiye Goker Bagca
- Department of Medical Biology, Faculty of Medicine, Ege University, Izmir, 35080, Turkey
| | - Gulperi Oktem
- Department of Histology and Embryology, Faculty of Medicine, Ege University, Izmir, 35080, Turkey.,Department of Stem Cell, Institute of Health Science, Ege University, Izmir, 35080, Turkey
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8
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Kim JH, Hanlon CD, Vohra S, Devreotes PN, Andrew DJ. Hedgehog signaling and Tre1 regulate actin dynamics through PI(4,5)P 2 to direct migration of Drosophila embryonic germ cells. Cell Rep 2021; 34:108799. [PMID: 33657369 PMCID: PMC8023404 DOI: 10.1016/j.celrep.2021.108799] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 12/21/2020] [Accepted: 02/05/2021] [Indexed: 01/09/2023] Open
Abstract
The Tre1 G-protein coupled receptor (GPCR) was discovered to be required for Drosophila germ cell (GC) coalescence almost two decades ago, yet the molecular events both upstream and downstream of Tre1 activation remain poorly understood. To gain insight into these events, we describe a bona fide null allele and both untagged and tagged versions of Tre1. We find that the primary defect with complete Tre1 loss is the failure of GCs to properly navigate, with GC mis-migration occurring from early stages. We find that Tre1 localizes with F-actin at the migration front, along with PI(4,5)P2; dPIP5K, an enzyme that generates PI(4,5)P2; and dWIP, a protein that binds activated Wiskott-Aldrich syndrome protein (WASP), which stimulates F-actin polymerization. We show that Tre1 is required for polarized accumulation of F-actin, PI(4,5)P2, and dPIP5K. Smoothened also localizes with F-actin at the migration front, and Hh, through Smo, increases levels of Tre1 at the plasma membrane and Tre1’s association with dPIP5K. Kim et al. uncover molecular and cellular events upstream and downstream of the Tre1 G-protein coupled receptor (GPCR), which is required for germ cell navigation in Drosophila. Hedgehog signaling through Smoothened localizes Tre1 to activate F-actin assembly through dPIP5K, PI(4,5)P2, and WASP.
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Affiliation(s)
- Ji Hoon Kim
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Caitlin D Hanlon
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sunaina Vohra
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Peter N Devreotes
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Deborah J Andrew
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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9
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Derrick DJA, Wolton K, Currie RA, Tindall MJ. A mathematical model of the role of aggregation in sonic hedgehog signalling. PLoS Comput Biol 2021; 17:e1008562. [PMID: 33617524 PMCID: PMC7932509 DOI: 10.1371/journal.pcbi.1008562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 03/04/2021] [Accepted: 11/23/2020] [Indexed: 11/25/2022] Open
Abstract
Effective regulation of the sonic hedgehog (Shh) signalling pathway is essential for normal development in a wide variety of species. Correct Shh signalling requires the formation of Shh aggregates on the surface of producing cells. Shh aggregates subsequently diffuse away and are recognised in receiving cells located elsewhere in the developing embryo. Various mechanisms have been postulated regarding how these aggregates form and what their precise role is in the overall signalling process. To understand the role of these mechanisms in the overall signalling process, we formulate and analyse a mathematical model of Shh aggregation using nonlinear ordinary differential equations. We consider Shh aggregate formation to comprise of multimerisation, association with heparan sulfate proteoglycans (HSPG) and binding with lipoproteins. We show that the size distribution of the Shh aggregates formed on the producing cell surface resembles an exponential distribution, a result in agreement with experimental data. A detailed sensitivity analysis of our model reveals that this exponential distribution is robust to parameter changes, and subsequently, also to variations in the processes by which Shh is recruited by HSPGs and lipoproteins. The work demonstrates the time taken for different sized Shh aggregates to form and the important role this likely plays in Shh diffusion. The sonic hedgehog (Shh) pathway is vital for normal development in a wide variety of species and its activity is strictly regulated to ensure correct spatiotemporal patterning of numerous developing tissues. Shh signalling requires the formation of Shh aggregates, formed on producing cells via a range of different mechanisms, that then diffuse to receiving cells. We formulate and analyse a mathematical model of the most well described mechanisms, namely monomer multimerisation, and recruitment of Shh by heparan sulfate proteoglycans and lipoproteins. Our results illustrate a distribution of the size and quantities of aggregates formed by these mechanisms. We found that as a consequence of competition between the mechanisms for Shh monomers the shape distribution of Shh aggregates resembles an exponential distribution. We also found the distribution to be robust to both parameter changes and variations to the processes by which mechanisms recruit Shh. We report that our approach and subsequent results demonstrate that these mechanisms act in synergy allowing Shh to aggregate in various quantities with diverse diffusive abilities. We postulate that this regulation contributes significantly to aid precision in signalling for Shh in areas of development.
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Affiliation(s)
- Daniel J. A. Derrick
- Department of Mathematics and Statistics, University of Reading, Whiteknights, Reading, United Kingdom
| | - Kathryn Wolton
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire, United Kingdom
| | - Richard A. Currie
- Syngenta, Jealott’s Hill International Research Centre, Bracknell, Berkshire, United Kingdom
| | - Marcus John Tindall
- Department of Mathematics and Statistics, University of Reading, Whiteknights, Reading, United Kingdom
- Institute of Cardiovascular and Metabolic Research, University of Reading, Whiteknights, Reading, United Kingdom
- * E-mail:
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10
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Johnson BP, Vitek RA, Morgan MM, Fink DM, Beames TG, Geiger PG, Beebe DJ, Lipinski RJ. A Microphysiological Approach to Evaluate Effectors of Intercellular Hedgehog Signaling in Development. Front Cell Dev Biol 2021; 9:621442. [PMID: 33634122 PMCID: PMC7900501 DOI: 10.3389/fcell.2021.621442] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 01/08/2021] [Indexed: 12/14/2022] Open
Abstract
Paracrine signaling in the tissue microenvironment is a central mediator of morphogenesis, and modeling this dynamic intercellular activity in vitro is critical to understanding normal and abnormal development. For example, Sonic Hedgehog (Shh) signaling is a conserved mechanism involved in multiple developmental processes and strongly linked to human birth defects including orofacial clefts of the lip and palate. SHH ligand produced, processed, and secreted from the epithelial ectoderm is shuttled through the extracellular matrix where it binds mesenchymal receptors, establishing a gradient of transcriptional response that drives orofacial morphogenesis. In humans, complex interactions of genetic predispositions and environmental insults acting on diverse molecular targets are thought to underlie orofacial cleft etiology. Consequently, there is a need for tractable in vitro approaches that model this complex cellular and environmental interplay and are sensitive to disruption across the multistep signaling cascade. We developed a microplate-based device that supports an epithelium directly overlaid onto an extracellular matrix-embedded mesenchyme, mimicking the basic tissue architecture of developing orofacial tissues. SHH ligand produced from the epithelium generated a gradient of SHH-driven transcription in the adjacent mesenchyme, recapitulating the gradient of pathway activity observed in vivo. Shh pathway activation was antagonized by small molecule inhibitors of epithelial secretory, extracellular matrix transport, and mesenchymal sensing targets, supporting the use of this approach in high-content chemical screening of the complete Shh pathway. Together, these findings demonstrate a novel and practical microphysiological model with broad utility for investigating epithelial-mesenchymal interactions and environmental signaling disruptions in development.
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Affiliation(s)
- Brian P Johnson
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, United States.,Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, United States.,Department of Biomedical Engineering, Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States.,Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, United States
| | - Ross A Vitek
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, United States
| | - Molly M Morgan
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, United States
| | - Dustin M Fink
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
| | - Tyler G Beames
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, United States.,Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
| | - Peter G Geiger
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, United States
| | - David J Beebe
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, United States
| | - Robert J Lipinski
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI, United States.,Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
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11
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A biomimetic engineered bone platform for advanced testing of prosthetic implants. Sci Rep 2020; 10:22154. [PMID: 33335113 PMCID: PMC7747643 DOI: 10.1038/s41598-020-78416-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 11/09/2020] [Indexed: 02/08/2023] Open
Abstract
Existing methods for testing prosthetic implants suffer from critical limitations, creating an urgent need for new strategies that facilitate research and development of implants with enhanced osseointegration potential. Herein, we describe a novel, biomimetic, human bone platform for advanced testing of implants in vitro, and demonstrate the scientific validity and predictive value of this approach using an assortment of complementary evaluation methods. We anchored titanium (Ti) and stainless steel (SS) implants into biomimetic scaffolds, seeded with human induced mesenchymal stem cells, to recapitulate the osseointegration process in vitro. We show distinct patterns of gene expression, matrix deposition, and mineralization in response to the two materials, with Ti implants ultimately resulting in stronger integration strength, as seen in other preclinical and clinical studies. Interestingly, RNAseq analysis reveals that the TGF-beta and the FGF2 pathways are overexpressed in response to Ti implants, while the Wnt, BMP, and IGF pathways are overexpressed in response to SS implants. High-resolution imaging shows significantly increased tissue mineralization and calcium deposition at the tissue-implant interface in response to Ti implants, contributing to a twofold increase in pullout strength compared to SS implants. Our technology creates unprecedented research opportunities towards the design of implants and biomaterials that can be personalized, and exhibit enhanced osseointegration potential, with reduced need for animal testing.
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12
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Lézot F, Corre I, Morice S, Rédini F, Verrecchia F. SHH Signaling Pathway Drives Pediatric Bone Sarcoma Progression. Cells 2020; 9:cells9030536. [PMID: 32110934 PMCID: PMC7140443 DOI: 10.3390/cells9030536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 02/07/2023] Open
Abstract
Primary bone tumors can be divided into two classes, benign and malignant. Among the latter group, osteosarcoma and Ewing sarcoma are the most prevalent malignant primary bone tumors in children and adolescents. Despite intensive efforts to improve treatments, almost 40% of patients succumb to the disease. Specifically, the clinical outcome for metastatic osteosarcoma or Ewing sarcoma remains poor; less than 30% of patients who present metastases will survive 5 years after initial diagnosis. One common and specific point of these bone tumors is their ability to deregulate bone homeostasis and remodeling and divert them to their benefit. Over the past years, considerable interest in the Sonic Hedgehog (SHH) pathway has taken place within the cancer research community. The activation of this SHH cascade can be done through different ways and, schematically, two pathways can be described, the canonical and the non-canonical. This review discusses the current knowledge about the involvement of the SHH signaling pathway in skeletal development, pediatric bone sarcoma progression and the related therapeutic options that may be possible for these tumors.
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13
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Sasai N, Toriyama M, Kondo T. Hedgehog Signal and Genetic Disorders. Front Genet 2019; 10:1103. [PMID: 31781166 PMCID: PMC6856222 DOI: 10.3389/fgene.2019.01103] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 10/11/2019] [Indexed: 12/12/2022] Open
Abstract
The hedgehog (Hh) family comprises sonic hedgehog (Shh), Indian hedgehog (Ihh), and desert hedgehog (Dhh), which are versatile signaling molecules involved in a wide spectrum of biological events including cell differentiation, proliferation, and survival; establishment of the vertebrate body plan; and aging. These molecules play critical roles from embryogenesis to adult stages; therefore, alterations such as abnormal expression or mutations of the genes involved and their downstream factors cause a variety of genetic disorders at different stages. The Hh family involves many signaling mediators and functions through complex mechanisms, and achieving a comprehensive understanding of the entire signaling system is challenging. This review discusses the signaling mediators of the Hh pathway and their functions at the cellular and organismal levels. We first focus on the roles of Hh signaling mediators in signal transduction at the cellular level and the networks formed by these factors. Then, we analyze the spatiotemporal pattern of expression of Hh pathway molecules in tissues and organs, and describe the phenotypes of mutant mice. Finally, we discuss the genetic disorders caused by malfunction of Hh signaling-related molecules in humans.
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Affiliation(s)
- Noriaki Sasai
- Developmental Biomedical Science, Division of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Michinori Toriyama
- Systems Neurobiology and Medicine, Division of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
- Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Toru Kondo
- Division of Stem Cell Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
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Bonn-Breach R, Gu Y, Jenkins J, Fasan R, Wedekind J. Structure of Sonic Hedgehog protein in complex with zinc(II) and magnesium(II) reveals ion-coordination plasticity relevant to peptide drug design. Acta Crystallogr D Struct Biol 2019; 75:969-979. [PMID: 31692471 PMCID: PMC6834079 DOI: 10.1107/s2059798319012890] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 09/17/2019] [Indexed: 12/21/2022] Open
Abstract
The Hedgehog pathway is an essential cell-signaling paradigm implicated in cancer tumorigenesis and the developmental disorder holoprosencephaly, making it an attractive target for therapeutic design. The N-terminal domain of the Sonic Hedgehog protein (Shh-N) is the essential signaling molecule in the Hedgehog pathway. In this role Shh-N interacts with its cognate membrane receptor Patched, as well as the regulatory proteins HHIP and CDO, by utilizing interfaces harboring one or more divalent ions. Here, the crystal structure of human Shh-N is presented at 1.43 Å resolution, representing a landmark in the characterization of this protein. The structure reveals that the conserved Zn2+-binding site adopts an atypical octahedral coordination geometry, whereas an adjacent binding site, normally occupied by binuclear Ca2+, has been supplanted by a single octahedrally bound Mg2+. Both divalent sites are compared with those in previous Shh-N structures, which demonstrates a significant degree of plasticity of the Shh-N protein in terms of divalent ion binding. The presence of a high Mg2+ concentration in the crystallization medium appears to have influenced metal loading at both metal ion-binding sites. These observations have technical and design implications for efforts focused on the development of inhibitors that target Shh-N-mediated protein-protein interactions.
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Affiliation(s)
- Rachel Bonn-Breach
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Yu Gu
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627, USA
| | - Jermaine Jenkins
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Rudi Fasan
- Department of Chemistry, University of Rochester, 120 Trustee Road, Rochester, NY 14627, USA
| | - Joseph Wedekind
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Rochester, NY 14642, USA
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Su KH, Dai S, Tang Z, Xu M, Dai C. Heat Shock Factor 1 Is a Direct Antagonist of AMP-Activated Protein Kinase. Mol Cell 2019; 76:546-561.e8. [PMID: 31561952 DOI: 10.1016/j.molcel.2019.08.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 06/03/2019] [Accepted: 08/21/2019] [Indexed: 02/08/2023]
Abstract
Through transcriptional control of the evolutionarily conserved heat shock, or proteotoxic stress, response, heat shock factor 1 (HSF1) preserves proteomic stability. Here, we show that HSF1, a physiological substrate for AMP-activated protein kinase (AMPK), constitutively suppresses this central metabolic sensor. By physically evoking conformational switching of AMPK, HSF1 impairs AMP binding to the γ subunits and enhances the PP2A-mediated de-phosphorylation, but it impedes the LKB1-mediated phosphorylation of Thr172, and retards ATP binding to the catalytic α subunits. These immediate and manifold regulations empower HSF1 to both repress AMPK under basal conditions and restrain its activation by diverse stimuli, thereby promoting lipogenesis, cholesterol synthesis, and protein cholesteroylation. In vivo, HSF1 antagonizes AMPK to control body fat mass and drive the lipogenic phenotype and growth of melanomas independently of its intrinsic transcriptional action. Thus, the physical AMPK-HSF1 interaction epitomizes a reciprocal kinase-substrate regulation whereby lipid metabolism and proteomic stability intertwine.
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Affiliation(s)
- Kuo-Hui Su
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - Siyuan Dai
- Graduate School of Biomedical Sciences, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Zijian Tang
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, USA; Graduate programs, Department of Molecular & Biomedical Sciences, The University of Maine, Orono, ME 04469, USA
| | - Meng Xu
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, USA
| | - Chengkai Dai
- Mouse Cancer Genetics Program, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, USA.
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16
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Aravani D, Morris GE, Jones PD, Tattersall HK, Karamanavi E, Kaiser MA, Kostogrys RB, Ghaderi Najafabadi M, Andrews SL, Nath M, Ye S, Stringer EJ, Samani NJ, Webb TR. HHIPL1, a Gene at the 14q32 Coronary Artery Disease Locus, Positively Regulates Hedgehog Signaling and Promotes Atherosclerosis. Circulation 2019; 140:500-513. [PMID: 31163988 PMCID: PMC6686954 DOI: 10.1161/circulationaha.119.041059] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Supplemental Digital Content is available in the text. Background: Genome-wide association studies have identified chromosome 14q32 as a locus for coronary artery disease. The disease-associated variants fall in a hitherto uncharacterized gene called HHIPL1 (hedgehog interacting protein-like 1), which encodes a sequence homolog of an antagonist of hedgehog signaling. The function of HHIPL1 and its role in atherosclerosis are unknown. Methods: HHIPL1 cellular localization, interaction with sonic hedgehog (SHH), and influence on hedgehog signaling were tested. HHIPL1 expression was measured in coronary artery disease–relevant human cells, and protein localization was assessed in wild-type and Apoe−/− (apolipoprotein E deficient) mice. Human aortic smooth muscle cell phenotypes and hedgehog signaling were investigated after gene knockdown. Hhipl1−/− mice were generated and aortic smooth muscle cells collected for phenotypic analysis and assessment of hedgehog signaling activity. Hhipl1−/− mice were bred onto both the Apoe−/− and Ldlr−/− (low-density lipoprotein receptor deficient) knockout strains, and the extent of atherosclerosis was quantified after 12 weeks of high-fat diet. Cellular composition and collagen content of aortic plaques were assessed by immunohistochemistry. Results: In vitro analyses revealed that HHIPL1 is a secreted protein that interacts with SHH and increases hedgehog signaling activity. HHIPL1 expression was detected in human smooth muscle cells and in smooth muscle within atherosclerotic plaques of Apoe−/− mice. The expression of Hhipl1 increased with disease progression in aortic roots of Apoe−/− mice. Proliferation and migration were reduced in Hhipl1 knockout mouse and HHIPL1 knockdown aortic smooth muscle cells, and hedgehog signaling was decreased in HHIPL1-deficient cells. Hhipl1 knockout caused a reduction of >50% in atherosclerosis burden on both Apoe−/− and Ldlr−/− knockout backgrounds, and lesions were characterized by reduced smooth muscle cell content. Conclusions: HHIPL1 is a secreted proatherogenic protein that enhances hedgehog signaling and regulates smooth muscle cell proliferation and migration. Inhibition of HHIPL1 protein function might offer a novel therapeutic strategy for coronary artery disease.
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Affiliation(s)
- Dimitra Aravani
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Gavin E Morris
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Peter D Jones
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Helena K Tattersall
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Elisavet Karamanavi
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Michael A Kaiser
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Renata B Kostogrys
- Department of Human Nutrition, Faculty of Food Technology, University of Agriculture in Kraków, Poland (R.B.K)
| | - Maryam Ghaderi Najafabadi
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Sarah L Andrews
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Mintu Nath
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Shu Ye
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Emma J Stringer
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Nilesh J Samani
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
| | - Tom R Webb
- Department of Cardiovascular Sciences, University of Leicester and National Institute for Health Research Leicester Biomedical Research Centre, Glenfield Hospital, United Kingdom (D.A., G.E.M., P.D.J., H.K.T., E.K., M.A.K., M.G.N., S.L.A., M.N., S.Y., E.J.S., N.J.S., T.R.W.)
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Chimento A, Casaburi I, Avena P, Trotta F, De Luca A, Rago V, Pezzi V, Sirianni R. Cholesterol and Its Metabolites in Tumor Growth: Therapeutic Potential of Statins in Cancer Treatment. Front Endocrinol (Lausanne) 2018; 9:807. [PMID: 30719023 PMCID: PMC6348274 DOI: 10.3389/fendo.2018.00807] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/21/2018] [Indexed: 12/13/2022] Open
Abstract
Cholesterol is essential for cell function and viability. It is a component of the plasma membrane and lipid rafts and is a precursor for bile acids, steroid hormones, and Vitamin D. As a ligand for estrogen-related receptor alpha (ESRRA), cholesterol becomes a signaling molecule. Furthermore, cholesterol-derived oxysterols activate liver X receptors (LXRs) or estrogen receptors (ERs). Several studies performed in cancer cells reveal that cholesterol synthesis is enhanced compared to normal cells. Additionally, high serum cholesterol levels are associated with increased risk for many cancers, but thus far, clinical trials with 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) have had mixed results. Statins inhibit cholesterol synthesis within cells through the inhibition of HMG-CoA reductase, the rate-limiting enzyme in the mevalonate and cholesterol synthetic pathway. Many downstream products of mevalonate have a role in cell proliferation, since they are required for maintenance of membrane integrity; signaling, as some proteins to be active must undergo prenylation; protein synthesis, as isopentenyladenine is an essential substrate for the modification of certain tRNAs; and cell-cycle progression. In this review starting from recent acquired findings on the role that cholesterol and its metabolites fulfill in the contest of cancer cells, we discuss the results of studies focused to investigate the use of statins in order to prevent cancer growth and metastasis.
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18
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Engelking LJ, Cantoria MJ, Xu Y, Liang G. Developmental and extrahepatic physiological functions of SREBP pathway genes in mice. Semin Cell Dev Biol 2017; 81:98-109. [PMID: 28736205 DOI: 10.1016/j.semcdb.2017.07.011] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/07/2017] [Indexed: 12/17/2022]
Abstract
Sterol regulatory element-binding proteins (SREBPs), master transcriptional regulators of cholesterol and fatty acid synthesis, have been found to contribute to a diverse array of cellular processes. In this review, we focus on genetically engineered mice in which the activities of six components of the SREBP gene pathway, namely SREBP-1, SREBP-2, Scap, Insig-1, Insig-2, or Site-1 protease have been altered through gene knockout or transgenic approaches. In addition to the expected impacts on lipid metabolism, manipulation of these genes in mice is found to affect a wide array of developmental and physiologic processes ranging from interferon signaling in macrophages to synaptic transmission in the brain. The findings reviewed herein provide a blueprint to guide future studies defining the complex interactions between lipid biology and the physiologic processes of many distinct organ systems.
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Affiliation(s)
- Luke J Engelking
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Mary Jo Cantoria
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Yanchao Xu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guosheng Liang
- Departments of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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19
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Ali SA, Al-Jazrawe M, Ma H, Whetstone H, Poon R, Farr S, Naples M, Adeli K, Alman BA. Regulation of Cholesterol Homeostasis by Hedgehog Signaling in Osteoarthritic Cartilage. Arthritis Rheumatol 2016; 68:127-37. [PMID: 26315393 PMCID: PMC4690757 DOI: 10.1002/art.39337] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Accepted: 08/13/2015] [Indexed: 12/11/2022]
Abstract
Objective With no effective therapies to attenuate cartilage degeneration in osteoarthritis (OA), the result is pain and disability. Activation of hedgehog (HH) signaling causes changes related to the progression of OA, with higher levels of Gli‐mediated transcriptional activation associated with increased disease severity. To elucidate the mechanism through which this occurs, this study sought to identify genes regulated by HH signaling in human OA chondrocytes. Methods Using human OA cartilage samples, microarray analyses were performed to detect changes in gene expression when the HH pathway was modulated. Results were analyzed for differentially expressed genes, grouped into functional networks, and validated in independent samples. To investigate the effects of chondrocyte‐specific sterol accumulation, we generated mice lacking Insig1 and Insig2, which are major negative regulators of cholesterol homeostasis, under Col2a1 regulatory elements. Results HH signaling was found to regulate genes that govern cholesterol homeostasis, and this led to alterations in cholesterol accumulation in chondrocytes. A higher level of Gli‐mediated transcription resulted in accumulation of intracellular cholesterol. In genetically modified mice, chondrocyte‐specific cholesterol accumulation was associated with an OA phenotype. Reducing cholesterol accumulation attenuated the severity of OA in mice in vivo and decreased the expression of proteases in human OA cartilage in vitro. Conclusion HH signaling regulates cholesterol homeostasis in chondrocytes, and intracellular cholesterol accumulation contributes to the severity of OA. Our findings have therapeutic implications, since reduction of HH signaling reversed cholesterol accumulation and statin treatment attenuated cartilage degeneration.
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Affiliation(s)
- Shabana Amanda Ali
- University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mushriq Al-Jazrawe
- University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
| | - Henry Ma
- University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Raymond Poon
- Hospital for Sick Children, Toronto, Ontario, Canada
| | - Sarah Farr
- University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mark Naples
- Hospital for Sick Children, Toronto, Ontario, Canada
| | - Khosrow Adeli
- University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada
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20
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Gurdziel K, Vogt KR, Schneider G, Richards N, Gumucio DL. Computational prediction and experimental validation of novel Hedgehog-responsive enhancers linked to genes of the Hedgehog pathway. BMC DEVELOPMENTAL BIOLOGY 2016; 16:4. [PMID: 26912062 PMCID: PMC4765071 DOI: 10.1186/s12861-016-0106-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/16/2016] [Indexed: 12/14/2022]
Abstract
BACKGROUND The Hedgehog (Hh) signaling pathway, acting through three homologous transcription factors (GLI1, GLI2, GLI3) in vertebrates, plays multiple roles in embryonic organ development and adult tissue homeostasis. At the level of the genome, GLI factors bind to specific motifs in enhancers, some of which are hundreds of kilobases removed from the gene promoter. These enhancers integrate the Hh signal in a context-specific manner to control the spatiotemporal pattern of target gene expression. Importantly, a number of genes that encode Hh pathway molecules are themselves targets of Hh signaling, allowing pathway regulation by an intricate balance of feed-back activation and inhibition. However, surprisingly few of the critical enhancer elements that control these pathway target genes have been identified despite the fact that such elements are central determinants of Hh signaling activity. Recently, ChIP studies have been carried out in multiple tissue contexts using mouse models carrying FLAG-tagged GLI proteins (GLI(FLAG)). Using these datasets, we tested whether a meta-analysis of GLI binding sites, coupled with a machine learning approach, could reveal genomic features that could be used to empirically identify Hh-regulated enhancers linked to loci of the Hh signaling pathway. RESULTS A meta-analysis of four existing GLI(FLAG) datasets revealed a library of GLI binding motifs that was substantially more restricted than the potential sites predicted by previous in vitro binding studies. A machine learning method (kmer-SVM) was then applied to these datasets and enriched k-mers were identified that, when applied to the mouse genome, predicted as many as 37,000 potential Hh enhancers. For functional analysis, we selected nine regions which were annotated to putative Hh pathway molecules and found that seven exhibited GLI-dependent activity, indicating that they are directly regulated by Hh signaling (78% success rate). CONCLUSIONS The results suggest that Hh enhancer regions share common sequence features. The kmer-SVM machine learning approach identifies those features and can successfully predict functional Hh regulatory regions in genomic DNA surrounding Hh pathway molecules and likely, other Hh targets. Additionally, the library of enriched GLI binding motifs that we have identified may allow improved identification of functional GLI binding sites.
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Affiliation(s)
- Katherine Gurdziel
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
- Department of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Kyle R Vogt
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Gary Schneider
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Neil Richards
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Deborah L Gumucio
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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21
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Callahan BP, Wang C. Hedgehog Cholesterolysis: Specialized Gatekeeper to Oncogenic Signaling. Cancers (Basel) 2015; 7:2037-53. [PMID: 26473928 PMCID: PMC4695875 DOI: 10.3390/cancers7040875] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/22/2015] [Accepted: 09/28/2015] [Indexed: 12/16/2022] Open
Abstract
Discussions of therapeutic suppression of hedgehog (Hh) signaling almost exclusively focus on receptor antagonism; however, hedgehog's biosynthesis represents a unique and potentially targetable aspect of this oncogenic signaling pathway. Here, we review a key biosynthetic step called cholesterolysis from the perspectives of structure/function and small molecule inhibition. Cholesterolysis, also called cholesteroylation, generates cholesterol-modified Hh ligand via autoprocessing of a hedgehog precursor protein. Post-translational modification by cholesterol appears to be restricted to proteins in the hedgehog family. The transformation is essential for Hh biological activity and upstream of signaling events. Despite its decisive role in generating ligand, cholesterolysis remains conspicuously unexplored as a therapeutic target.
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Affiliation(s)
- Brian P Callahan
- Chemistry Department, Binghamton University 4400 Vestal Parkway East, Binghamton, NY 13902, USA.
| | - Chunyu Wang
- Biology Department, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY 12180, USA.
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22
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Porter TD. Electron Transfer Pathways in Cholesterol Synthesis. Lipids 2015; 50:927-36. [PMID: 26344922 DOI: 10.1007/s11745-015-4065-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/21/2015] [Indexed: 12/17/2022]
Abstract
Cholesterol synthesis in the endoplasmic reticulum requires electron input at multiple steps and utilizes both NADH and NADPH as the electron source. Four enzymes catalyzing five steps in the pathway require electron input: squalene monooxygenase, lanosterol demethylase, sterol 4α-methyl oxidase, and sterol C5-desaturase. The electron-donor proteins for these enzymes include cytochrome P450 reductase and the cytochrome b5 pathway. Here I review the evidence for electron donor protein requirements with these enzymes, the evidence for additional electron donor pathways, and the effect of deletion of these redox enzymes on cholesterol and lipid metabolism.
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Affiliation(s)
- Todd D Porter
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, 40536-0596, USA.
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23
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Pan YB, Gong Y, Ruan HF, Pan LY, Wu XK, Tang C, Wang CJ, Zhu HB, Zhang ZM, Tang LF, Zou CC, Wang HB, Wu XM. Sonic hedgehog through Gli2 and Gli3 is required for the proper development of placental labyrinth. Cell Death Dis 2015; 6:e1653. [PMID: 25695606 PMCID: PMC4669788 DOI: 10.1038/cddis.2015.28] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/14/2015] [Accepted: 01/15/2015] [Indexed: 01/20/2023]
Abstract
Sonic hedgehog (Shh) functions as a conserved morphogen in the development of various organs in metazoans ranging from Drosophila to humans. Here, we have investigated the potential roles and underlying mechanisms of Shh signaling in murine placentation. Immunostaining revealed the abundant expression of the main components of Shh pathway in both the trophectoderm of blastocysts and developing placentas. Disruption of Shh led to impaired vascularogenesis of yolk sac, less branching and malformation of placental labyrinth, thereby leading to a robust decrease in capacity of transplacental passages. Moreover, placenta-specific gene incorporation by lentiviral transduction of mouse blastocysts and blastocyst transplantation robustly knocked down the expression of Gli3 and Gli2 in placenta but not in embryos. Finally, Gli3 knockdown in Shh−/− placentas partially rescued the defects of both yolk sac and placental labyrinth, and robustly restored the capacity of transplacental passages. Gli2 knockdown in Shh+/− placentas affected neither the capacity of tranplacental passages nor the vascularogenesis of yolk sac, however, it partially phenocopied the labyrinthine defects of Shh−/− placentas. Taken together, these results uncover that both Shh/Gli2 and Shh/Gli3 signals are required for proper development of murine placentas and are possibly essential for pregnant maintenance.
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Affiliation(s)
- Y B Pan
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - Y Gong
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - H F Ruan
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - L Y Pan
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - X K Wu
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - C Tang
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
| | - C J Wang
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - H B Zhu
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Z M Zhang
- Department of Gynaecology and Obstetrics, The First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - L F Tang
- Department of Internal Medicine, The Affiliated Children Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - C C Zou
- Department of Internal Medicine, The Affiliated Children Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - H B Wang
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - X M Wu
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou, China
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Wu CH, Bialecka-Fornal M, Newman DK. Methylation at the C-2 position of hopanoids increases rigidity in native bacterial membranes. eLife 2015; 4. [PMID: 25599566 PMCID: PMC4337730 DOI: 10.7554/elife.05663] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 01/14/2015] [Indexed: 12/17/2022] Open
Abstract
Sedimentary rocks host a vast reservoir of organic carbon, such as 2-methylhopane biomarkers, whose evolutionary significance we poorly understand. Our ability to interpret this molecular fossil record is constrained by ignorance of the function of their molecular antecedents. To gain insight into the meaning of 2-methylhopanes, we quantified the dominant (des)methylated hopanoid species in the membranes of the model hopanoid-producing bacterium Rhodopseudomonas palustris TIE-1. Fluorescence polarization studies of small unilamellar vesicles revealed that hopanoid 2-methylation specifically renders native bacterial membranes more rigid at concentrations that are relevant in vivo. That hopanoids differentially modify native membrane rigidity as a function of their methylation state indicates that methylation itself promotes fitness under stress. Moreover, knowing the in vivo (2Me)-hopanoid concentration range in different cell membranes, and appreciating that (2Me)-hopanoids' biophysical effects are tuned by the lipid environment, permits the design of more relevant in vitro experiments to study their physiological functions. DOI:http://dx.doi.org/10.7554/eLife.05663.001 The cell membrane that separates the inside of a cell from its outside environment is not a fixed structure. A cell can change the amount and type of different molecules in its membrane, which can alter the rigidity and permeability of the membrane and allow the cell to adapt to changing conditions. The cell membranes of many bacteria contain molecules called hopanoids. Hopanes are the fossilized forms of these molecules and many hopanes are found extensively in sedimentary rocks. For example, 2-methylated hopanes—the fossilized forms of hopanoids that have a methyl group added to a particular carbon atom—have been found in ancient rocks that formed up to 1.6 billion years ago. Many researchers have suggested that 2-methylated hopanes (and other molecular fossils) in sedimentary rocks could act as ‘biomarkers’ and be used to deduce what primitive life and ancient living conditions were like. Millions of years ago, several periods occurred where the Earth's oceans lost almost all of their oxygen; this likely placed all life on Earth under great stress. A greater proportion of the hopanes found in rocks formed during those periods are methylated than those seen in rocks from other time periods. However, it was difficult to interpret this observation about the fossil record, as the role of 2-methylated hopanoids in living bacterial cells was unknown. Wu et al. have now investigated the role of 2-methylated hopanoids by performing experiments on bacterial membranes and found that 2-methylated hopanoids help the other molecules that make up the membrane to pack more tightly together. This makes the membrane more rigid, and the extent of this stiffening depends on the length of the 2-methylated hopanoid and on the other molecules that are present in the membrane. A more rigid membrane would protect the bacteria more in times of stress; therefore, rock layers containing an increased amount of 2-methylhopane are likely to indicate times when the bacteria living at that time were under a great deal of stress. DOI:http://dx.doi.org/10.7554/eLife.05663.002
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Affiliation(s)
- Chia-Hung Wu
- Division of Biology and Biological Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, United States
| | - Maja Bialecka-Fornal
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Dianne K Newman
- Division of Biology and Biological Engineering, Howard Hughes Medical Institute, California Institute of Technology, Pasadena, United States
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Majumdar R, Sixt M, Parent CA. New paradigms in the establishment and maintenance of gradients during directed cell migration. Curr Opin Cell Biol 2014; 30:33-40. [PMID: 24959970 DOI: 10.1016/j.ceb.2014.05.010] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 05/27/2014] [Indexed: 11/16/2022]
Abstract
Directional guidance of migrating cells is relatively well explored in the reductionist setting of cell culture experiments. Here spatial gradients of chemical cues as well as gradients of mechanical substrate characteristics prove sufficient to attract single cells as well as their collectives. How such gradients present and act in the context of an organism is far less clear. Here we review recent advances in understanding how guidance cues emerge and operate in complex physiological settings.
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Affiliation(s)
- Ritankar Majumdar
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
| | - Michael Sixt
- IST Austria (Institute of Science and Technology Austria), 3400 Klostemeuburg, Austria
| | - Carole A Parent
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States.
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Hwang S, Thangapandian S, Lee KW. Molecular dynamics simulations of sonic hedgehog-receptor and inhibitor complexes and their applications for potential anticancer agent discovery. PLoS One 2013; 8:e68271. [PMID: 23935859 PMCID: PMC3729836 DOI: 10.1371/journal.pone.0068271] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/24/2013] [Indexed: 11/29/2022] Open
Abstract
The sonic hedgehog (Shh) signaling pathway is necessary for a variety of development and differentiation during embryogenesis as well as maintenance and renascence of diverse adult tissues. However, an abnormal activation of the signaling pathway is related to various cancers. In this pathway, the Shh signaling transduction is facilitated by binding of Shh to its receptor protein, Ptch. In this study, we modeled the 3D structure of functionally important key loop peptides of Ptch based on homologous proteins. Using this loop model, the molecular interactions between the structural components present in the pseudo-active site of Shh and key residues of Ptch was investigated in atomic level through molecular dynamics (MD) simulations. For the purpose of developing inhibitor candidates of the Shh signaling pathway, the Shh pseudo-active site of this interface region was selected as a target to block the direct binding between Shh and Ptch. Two different structure-based pharmacophore models were generated considering the key loop of Ptch and known inhibitor-induced conformational changes of the Shh through MD simulations. Finally two hit compounds were retrieved through a series of virtual screening combined with molecular docking simulations and we propose two hit compounds as potential inhibitory lead candidates to block the Shh signaling pathway based on their strong interactions to receptor or inhibitor induced conformations of the Shh.
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Affiliation(s)
- Swan Hwang
- Division of Applied Life Science (BK21 Program), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), Jinju, Republic of Korea
| | - Sundarapandian Thangapandian
- Division of Applied Life Science (BK21 Program), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), Jinju, Republic of Korea
| | - Keun Woo Lee
- Division of Applied Life Science (BK21 Program), Systems and Synthetic Agrobiotech Center (SSAC), Plant Molecular Biology and Biotechnology Research Center (PMBBRC), Research Institute of Natural Science (RINS), Gyeongsang National University (GNU), Jinju, Republic of Korea
- * E-mail:
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27
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The liver x receptor in correlation with other nuclear receptors in spontaneous and recurrent abortions. PPAR Res 2013; 2013:575604. [PMID: 23690759 PMCID: PMC3649716 DOI: 10.1155/2013/575604] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 02/07/2013] [Accepted: 03/14/2013] [Indexed: 01/29/2023] Open
Abstract
The liver X receptors (LXRs) have been shown to be crucially involved in maternal-fetal cholesterol transport and placentation. The aim of this study was to investigate the expression pattern and frequency of LXR under normal physiological circumstances and in spontaneous abortion and/or recurrent miscarriage. A total of 29 (12 physiologic pregnancies/10 spontaneous abortions/7 recurrent miscarriages) human pregnancies in first trimester were analysed for LXR expression. Expression changes were evaluated by immunohistochemistry for receptor and quantitative RT-PCR (TaqMan) was performed to determine the level of LXR mRNA expression. We also stained for RXRα and PPARγ as possible heterodimers of LXR. LXR expression was downregulated in the syncytiotrophoblast of spontaneous abortion placentas compared to normal pregnancy. In recurrent miscarriage there was a trend for a downregulation. Decidua showed an even stronger downregulation in both groups. In the syncytiotrophoblast we found a positive correlation for the combination of LXR/PPARγ in abortions and a negative correlation for LXR/RXRα. In addition, double-immunofluorescence staining showed that LXR as well as RXRα and PPARγ are expressed by the extravillous trophoblast. Finally, RXRα and LXR showed coexpression in the same extravillous trophoblast cells. To conclude, our data show that LXR expression is decreased in miscarriage.
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Valdes VJ, Athie A, Salinas LS, Navarro RE, Vaca L. CUP-1 is a novel protein involved in dietary cholesterol uptake in Caenorhabditis elegans. PLoS One 2012; 7:e33962. [PMID: 22479487 PMCID: PMC3313951 DOI: 10.1371/journal.pone.0033962] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 02/22/2012] [Indexed: 01/15/2023] Open
Abstract
Sterols transport and distribution are essential processes in all multicellular organisms. Survival of the nematode Caenorhabditis elegans depends on dietary absorption of sterols present in the environment. However the general mechanisms associated to sterol uptake in nematodes are poorly understood. In the present work we provide evidence showing that a previously uncharacterized transmembrane protein, designated Cholesterol Uptake Protein-1 (ChUP-1), [corrected] is involved in dietary cholesterol uptake in C. elegans. Animals lacking ChUP-1 [corrected] showed hypersensitivity to cholesterol limitation and were unable to uptake cholesterol. A ChUP-1-GFP [corrected] fusion protein colocalized with cholesterol-rich vesicles, endosomes and lysosomes as well as the plasma membrane. Additionally, by FRET imaging, a direct interaction was found between the cholesterol analog DHE and the transmembrane "cholesterol recognition/interaction amino acid consensus" (CRAC) motif present in C. elegans ChUP-1. [corrected]. In-silico analysis identified two mammalian homologues of ChUP-1. [corrected]. Most interestingly, CRAC motifs are conserved in mammalian ChUP-1 [corrected] homologous. Our results suggest a role of ChUP-1 [corrected] in cholesterol uptake in C. elegans and open up the possibility for the existence of a new class of proteins involved in sterol absorption in mammals.
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Affiliation(s)
| | | | | | - Rosa E. Navarro
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF, México
| | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, México DF, México
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29
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Chen W, Li L, Du Z, Liu J, Reitter JN, Mills KV, Linhardt RJ, Wang C. Intramolecular disulfide bond between catalytic cysteines in an intein precursor. J Am Chem Soc 2012; 134:2500-3. [PMID: 22280304 DOI: 10.1021/ja211010g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein splicing is a self-catalyzed and spontaneous post-translational process in which inteins excise themselves out of precursor proteins while the exteins are ligated together. We report the first discovery of an intramolecular disulfide bond between the two active-site cysteines, Cys1 and Cys+1, in an intein precursor composed of the hyperthermophilic Pyrococcus abyssi PolII intein and extein. The existence of this intramolecular disulfide bond is demonstrated by the effect of reducing agents on the precursor, mutagenesis, and liquid chromatography-mass spectrometry (LC-MS) with tandem MS (MS/MS) of the tryptic peptide containing the intramolecular disulfide bond. The disulfide bond inhibits protein splicing, and splicing can be induced by reducing agents such as tris(2-carboxyethyl)phosphine (TCEP). The stability of the intramolecular disulfide bond is enhanced by electrostatic interactions between the N- and C-exteins but is reduced by elevated temperature. The presence of this intramolecular disulfide bond may contribute to the redox control of splicing activity in hypoxia and at low temperature and point to the intriguing possibility that inteins may act as switches to control extein function.
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Affiliation(s)
- Wen Chen
- Department of Biology, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York 12180, USA
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30
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Seth A, Machingo QJ, Fritz A, Shur BD. Core fucosylation is required for midline patterning during zebrafish development. Dev Dyn 2011; 239:3380-90. [PMID: 21069830 DOI: 10.1002/dvdy.22475] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Complex carbohydrates represent one of the most polymorphic classes of macromolecules, but their functions during embryonic development remain poorly defined. Herein, we show that knockdown of FucT8, the fucosyltransferase responsible for adding an α1,6 fucosyl residue to the core region of N-linked oligosaccharides, results in defective midline patterning during zebrafish development. Reduced FucT8 expression leads to mild cyclopia, small forebrains, U-shaped somites, among other midline patterning defects. One of the principal FucT8 substrates was identified as Apolipoprotein B (ApoB), the major scaffold protein that is responsible for assembly and secretion of lipoprotein particles in vertebrates. In Drosophila, lipoprotein particles are thought to facilitate cell signaling by serving as a transport vehicle for lipid-modified cell signaling proteins, such as hedgehog. In this regard, knockdown of ApoB expression in zebrafish embryos leads to similar midline patterning defects as those seen in FucT8 morphant embryos. Furthermore, preliminary studies suggest that ApoB facilitates Sonic hedgehog signaling during zebrafish development, analogous to the function of lipoprotein particles during hedgehog signaling in Drosophila.
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Affiliation(s)
- Anandita Seth
- Department of Cell Biology, Emory University, Atlanta, Georgia, USA
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31
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Jung Y, Witek RP, Syn WK, Choi SS, Omenetti A, Premont R, Guy CD, Diehl AM. Signals from dying hepatocytes trigger growth of liver progenitors. Gut 2010; 59:655-65. [PMID: 20427400 PMCID: PMC3632642 DOI: 10.1136/gut.2009.204354] [Citation(s) in RCA: 131] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The death rate of mature hepatocytes is chronically increased in various liver diseases, triggering responses that prevent liver atrophy, but often cause fibrosis. Mice with targeted disruption of inhibitor kappa B kinase (Ikk) in hepatocytes (HEP mice) provide a model to investigate this process because inhibiting Ikk-nuclear factor-kappaB (NF-kappaB) signalling in hepatocytes increases their apoptosis. METHODS Cell proliferation, apoptosis, progenitors, fibrosis and production of Hedgehog (Hh) ligands (progenitor and myofibroblast growth factors) were compared in HEP and control mice before and after feeding methionine choline-deficient ethionine-supplemented (MCDE) diets. Ikkbeta was deleted from primary hepatocytes to determine the effects on Hh ligand production; Hh signalling was inhibited directly in progenitors to determine the effects on viability. Liver sections from patients were examined to assess relationships between hepatocyte production of Hh ligands, accumulation of myofibroblastic cells and liver fibrosis. RESULTS Disrupting the Ikk-NF-kappaB pathway in hepatocytes inhibited their proliferation but induced their production of Hh ligands. The latter provided viability signals for progenitors and myofibroblasts, enhancing accumulation of these cell types and causing fibrogenesis. Findings in the mouse models were recapitulated in diseased human livers. CONCLUSION Dying mature hepatocytes produce Hh ligands which promote the compensatory outgrowth of progenitors and myofibroblasts. These results help to explain why diseases that chronically increase hepatocyte death promote cirrhosis.
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Affiliation(s)
- Youngmi Jung
- Department of Medicine, Duke University, Durham, North Carolina
| | - Rafal P. Witek
- Department of Medicine, Duke University, Durham, North Carolina
| | - Wing-Kin Syn
- Department of Medicine, Duke University, Durham, North Carolina
| | - Steve S. Choi
- Department of Medicine, Duke University, Durham, North Carolina
| | | | - Richard Premont
- Department of Medicine, Duke University, Durham, North Carolina
| | - Cynthia D. Guy
- Department of Pathology, Duke University, Durham, North Carolina
| | - Anna Mae Diehl
- Department of Medicine, Duke University, Durham, North Carolina
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Cunningham D, Spychala K, McLarren KW, Garza LA, Boerkoel CF, Herman GE. Developmental expression pattern of the cholesterogenic enzyme NSDHL and negative selection of NSDHL-deficient cells in the heterozygous Bpa(1H)/+ mouse. Mol Genet Metab 2009; 98:356-66. [PMID: 19631568 PMCID: PMC2783206 DOI: 10.1016/j.ymgme.2009.06.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 06/30/2009] [Accepted: 06/30/2009] [Indexed: 12/22/2022]
Abstract
NSDHL (NAD(P)H sterol dehydrogenase-like), is a 3beta-hydroxysterol dehydrogenase thought to function in the demethylation of sterol precursors in one of the later steps of cholesterol biosynthesis. Mutations in the X-linked NSDHL gene cause CHILD syndrome in humans, and the male-lethal bare patches (Bpa) phenotype in mice. The relative level of NSDHL expression among different mouse tissues at several stages of embryogenesis and postnatal development was analyzed by immunohistochemistry. In wild type (WT) embryos, the highest levels of expression were seen in the liver, dorsal root ganglia, central nervous system, retina, adrenal gland and testis. Heterozygous Bpa(1H) females are mosaic for NSDHL expression due to normal random X-inactivation. NSDHL-deficient cells were detected in the developing cerebral cortex and retina of Bpa(1H) female embryos. In postnatal WT and Bpa(1H) animals, we compared the expression pattern of NSDHL in skin, an affected tissue; liver, a main site of cholesterol synthesis; and brain, a tissue dependent on endogenous synthesis of cholesterol due to lack of transport across the blood-brain barrier. Clonal populations of mutant cells were visible in the brain, skin and liver of Bpa(1H) pups. In the liver, the proportion of NSDHL negative cells dropped from approximately 50% at postnatal day 6 to approximately 20% at one year of age. In the brain, which showed the highest expression in cerebral cortical and hippocampal neurons, the proportion of NSDHL negative cells also dropped dramatically over the first year of life. Our results suggest that while NSDHL-deficient cells in the mosaic Bpa(1H) female are able to survive and differentiate during embryonic development, they are subject to negative selection over the life of the animal.
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Affiliation(s)
- David Cunningham
- The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.
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33
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Wen S, Li H, Liu J. Dynamic signaling for neural stem cell fate determination. Cell Adh Migr 2009; 3:107-17. [PMID: 19262166 DOI: 10.4161/cam.3.1.7602] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Central nervous system (CNS) development starts from neural stem cells (NSCs) which ultimately give rise to the three major cell types (neurons, oligodendrocytes and astrocytes) of the CNS. NSCs are specified in space- and time-related fashions, becoming spatially heterogeneous and generating a progressively restricted repertoire of cell types. Mammalian NSCs produce different cell types at different time points during development under the influence of multiple signaling pathways. These pathways act in a dynamic web mode to determine the fate of NSCs via modulating the expression and activity of distinct set of transcription factors which in turn trigger the transcription of neural fate-associated genes. This review thus introduces the major signal pathways, transcription factors and their cross-talks and coordinative interactions in NSC fate determination.
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Affiliation(s)
- Shu Wen
- Department of Cell Biology, College of Basic Medical Sciences, Dalian Medical University, Dalian, China
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34
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Ding J, Jiang D, Kurczy M, Nalepka J, Dudley B, Merkel EI, Porter FD, Ewing AG, Winograd N, Burgess J, Molyneaux K. Inhibition of HMG CoA reductase reveals an unexpected role for cholesterol during PGC migration in the mouse. BMC DEVELOPMENTAL BIOLOGY 2008; 8:120. [PMID: 19117526 PMCID: PMC2631600 DOI: 10.1186/1471-213x-8-120] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2008] [Accepted: 12/31/2008] [Indexed: 11/10/2022]
Abstract
BACKGROUND Primordial germ cells (PGCs) are the embryonic precursors of the sperm and eggs. Environmental or genetic defects that alter PGC development can impair fertility or cause formation of germ cell tumors. RESULTS We demonstrate a novel role for cholesterol during germ cell migration in mice. Cholesterol was measured in living tissue dissected from mouse embryos and was found to accumulate within the developing gonads as germ cells migrate to colonize these structures. Cholesterol synthesis was blocked in culture by inhibiting the activity of HMG CoA reductase (HMGCR) resulting in germ cell survival and migration defects. These defects were rescued by co-addition of isoprenoids and cholesterol, but neither compound alone was sufficient. In contrast, loss of the last or penultimate enzyme in cholesterol biosynthesis did not alter PGC numbers or position in vivo. However embryos that lack these enzymes do not exhibit cholesterol defects at the stage at which PGCs are migrating. This demonstrates that during gestation, the cholesterol required for PGC migration can be supplied maternally. CONCLUSION In the mouse, cholesterol is required for PGC survival and motility. It may act cell-autonomously by regulating clustering of growth factor receptors within PGCs or non cell-autonomously by controlling release of growth factors required for PGC guidance and survival.
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Affiliation(s)
- Jiaxi Ding
- Department of Genetics Case Western Reserve University, Cleveland, OH, USA
| | - DeChen Jiang
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Michael Kurczy
- Department of Chemistry, Penn State University, University Park, PA, USA
| | - Jennifer Nalepka
- Department of Genetics Case Western Reserve University, Cleveland, OH, USA
| | - Brian Dudley
- Department of Genetics Case Western Reserve University, Cleveland, OH, USA
| | - Erin I Merkel
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Forbes D Porter
- Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Andrew G Ewing
- Department of Chemistry, Penn State University, University Park, PA, USA
- Department of Chemistry, Gothenburg University, Kemivägen 4, SE-41296 Gothenburg, Sweden
| | - Nicholas Winograd
- Department of Chemistry, Penn State University, University Park, PA, USA
| | - James Burgess
- Department of Chemistry, Case Western Reserve University, Cleveland, OH, USA
| | - Kathleen Molyneaux
- Department of Genetics Case Western Reserve University, Cleveland, OH, USA
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Abstract
Thyroid hormone was first identified as a potent regulator of skeletal maturation at the growth plate more than forty years ago. Since that time, many in vitro and in vivo studies have confirmed that thyroid hormone regulates the critical transition between cell proliferation and terminal differentiation in the growth plate, specifically the maturation of growth plate chondrocytes into hypertrophic cells. However these studies have neither identified the molecular mechanisms involved in the regulation of skeletal maturation by thyroid hormone, nor demonstrated how the systemic actions of thyroid hormone interface with the local regulatory milieu of the growth plate. This article will review our current understanding of the role of thyroid hormone in regulating the process of endochondral ossification at the growth plate, as well as what is currently known about the molecular mechanisms involved in this regulation.
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Affiliation(s)
- Yvonne Y Shao
- Orthopaedic Research Center, Department of Orthopaedic Surgery, The Cleveland Clinic Foundation, Cleveland, OH, USA
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36
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Zugasti O, Rajan J, Kuwabara PE. The function and expansion of the Patched- and Hedgehog-related homologs in C. elegans. Genome Res 2006; 15:1402-10. [PMID: 16204193 PMCID: PMC1240083 DOI: 10.1101/gr.3935405] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The Hedgehog (Hh) signaling pathway promotes pattern formation and cell proliferation in Drosophila and vertebrates. Hh is a ligand that binds and represses the Patched (Ptc) receptor and thereby releases the latent activity of the multipass membrane protein Smoothened (Smo), which is essential for transducing the Hh signal. In Caenorhabditis elegans, the Hh signaling pathway has undergone considerable divergence. Surprisingly, obvious Smo and Hh homologs are absent whereas PTC, PTC-related (PTR), and a large family of nematode Hh-related (Hh-r) proteins are present. We find that the number of PTC-related and Hh-r proteins has expanded in C. elegans, and that this expansion occurred early in Nematoda. Moreover, the function of these proteins appears to be conserved in Caenorhabditis briggsae. Given our present understanding of the Hh signaling pathway, the absence of Hh and Smo raises many questions about the evolution and the function of the PTC, PTR, and Hh-r proteins in C. elegans. To gain insights into their roles, we performed a global survey of the phenotypes produced by RNA-mediated interference (RNAi). Our study reveals that these genes do not require Smo for activity and that they function in multiple aspects of C. elegans development, including molting, cytokinesis, growth, and pattern formation. Moreover, a subset of the PTC, PTR, and Hh-r proteins have the same RNAi phenotypes, indicating that they have the potential to participate in the same processes.
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Affiliation(s)
- Olivier Zugasti
- University of Bristol, Department of Biochemistry, School of Medical Sciences, Bristol BS8 1TD, United Kingdom
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Novatchkova M, Wildpaner M, Schweizer D, Eisenhaber F. PhyloDome--visualization of taxonomic distributions of domains occurring in eukaryote protein sequence sets. Nucleic Acids Res 2005; 33:W121-5. [PMID: 15980439 PMCID: PMC1160134 DOI: 10.1093/nar/gki373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The analysis of taxonomic distribution and lineage-specific variation of domains and domain combinations is an important step in the assessment of their functional roles and potential interoperability. In the study of eukaryote sequence sets with many multi-domain proteins, it can become laborious to evaluate the phylogenetic context of the many occurring domains and their mutual relationships. PhyloDome is an answer to that problem. It provides a fast overview on the taxonomic spreading and potential interrelation of domains that are either given as a list of names and PFAM/SMART accessions or derived from a user-defined set of sequences. This taxonomic distribution analysis can be helpful in protein function and interaction assignment as the comparative study of potential Hedgehog pathway members in C.elegans shows. An implementation of PhyloDome is accessible for public use as a WWW-Service at . Software components are available on request.
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Affiliation(s)
- Maria Novatchkova
- Gregor-Mendel-Institute (GMI) of the Austrian Academy of Sciences, Dr Ignaz Seipel-Platz 2, A-1010 Vienna, Austria.
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Hellemans J, Coucke PJ, Giedion A, Paepe AD, Kramer P, Beemer F, Mortier GR. Homozygous mutations in IHH cause acrocapitofemoral dysplasia, an autosomal recessive disorder with cone-shaped epiphyses in hands and hips. Am J Hum Genet 2003; 72:1040-6. [PMID: 12632327 PMCID: PMC1180335 DOI: 10.1086/374318] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2002] [Accepted: 01/13/2003] [Indexed: 12/20/2022] Open
Abstract
Acrocapitofemoral dysplasia is a recently delineated autosomal recessive skeletal dysplasia, characterized clinically by short stature with short limbs and radiographically by cone-shaped epiphyses, mainly in hands and hips. Genomewide homozygosity mapping in two consanguineous families linked the locus to 2q35-q36 with a maximum two-point LOD score of 8.02 at marker D2S2248. Two recombination events defined the minimal critical region between markers D2S2248 and D2S2151 (3.74 cM). Using a candidate-gene approach, we identified two missense mutations in the amino-terminal signaling domain of the gene encoding Indian hedgehog (IHH). Both affected individuals of family 1 are homozygous for a 137C-->T transition (P46L), and the three patients in family 2 are homozygous for a 569T-->C transition (V190A). The two mutant amino acids are strongly conserved and predicted to be located outside the region where brachydactyly type A-1 mutations are clustered.
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Affiliation(s)
- Jan Hellemans
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Paul J. Coucke
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Andres Giedion
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Anne De Paepe
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Peter Kramer
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Frits Beemer
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
| | - Geert R. Mortier
- Department of Medical Genetics, Ghent University Hospital, Ghent, Belgium; Department of Radiology, Children’s Hospital Zürich, Zurich; and Departments of Radiology and Medical Genetics, Division of Biomedical Genetics, University Medical Center, Utrecht
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Porter FD. Malformation syndromes due to inborn errors of cholesterol synthesis. J Clin Invest 2002; 110:715-24. [PMID: 12235098 PMCID: PMC151134 DOI: 10.1172/jci16386] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Affiliation(s)
- Forbes D Porter
- Heritable Disorders Branch, National Institute of Child Health and Human Development, NIH, Bethesda, Maryland 20892, USA.
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Affiliation(s)
- Kai Simons
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.
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