51
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Jové M, Moreno-Navarrete JM, Pamplona R, Ricart W, Portero-Otín M, Fernández-Real JM. Human omental and subcutaneous adipose tissue exhibit specific lipidomic signatures. FASEB J 2013; 28:1071-81. [PMID: 24265485 DOI: 10.1096/fj.13-234419] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Despite their differential effects on human metabolic pathophysiology, the differences in omental and subcutaneous lipidomes are largely unknown. To explore this field, liquid chromatography coupled with mass spectrometry was used for lipidome analyses of adipose tissue samples (visceral and subcutaneous) selected from a group of obese subjects (n=38). Transcriptomics and in vitro studies in adipocytes were used to confirm the pathways affected by location. The analyses revealed the existence of obesity-related specific lipidome signatures in each of these locations, attributed to selective enrichment of specific triglycerides, glycerophospholipids, and sphingolipids, because these were not observed in adipose tissues from nonobese individuals. The changes were compatible with subcutaneous enrichment in pathways involved in adipogenesis, triacylglyceride synthesis, and lipid droplet formation, as well as increased α-oxidation. Marked differences between omental and subcutaneous depots in obese individuals were seen in the association of lipid species with metabolic traits (body mass index and insulin sensitivity). Targeted studies also revealed increased cholesterol (Δ56%) and cholesterol epoxide (Δ34%) concentrations in omental adipose tissue. In view of the effects of cholesterol epoxide, which induced enhanced expression of adipocyte differentiation and α-oxidation genes in human omental adipocytes, a novel role for cholesterol epoxide as a signaling molecule for differentiation is proposed. In summary, in obesity, adipose tissue exhibits a location-specific differential lipid profile that may contribute to explaining part of its distinct pathogenic role.
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Affiliation(s)
- Mariona Jové
- 1Section of Diabetes, Endocrinology and Nutrition, Hospital of Girona "Dr Josep Trueta," Carretera de França s/n, 17007, Girona, Spain.
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52
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Hadden MK. Hedgehog pathway agonism: therapeutic potential and small-molecule development. ChemMedChem 2013; 9:27-37. [PMID: 24203435 DOI: 10.1002/cmdc.201300358] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Indexed: 11/10/2022]
Abstract
The Hedgehog (Hh) pathway is a developmental signaling pathway that plays multiple roles during embryonic development and in adult tissues. Constitutive Hh signaling has been linked to the development and progression of several forms of cancer, and the application of small-molecule pathway inhibitors as anticancer chemotherapeutics is well studied and clearly defined. Activation of the Hh pathway as a therapeutic strategy for a variety of degenerative or ischemic disorders has also been proposed; however, the development of small-molecule Hh agonists has received less attention. The goal of this review is to highlight the recent evidence supporting the therapeutic potential of Hh pathway activators and to provide a comprehensive overview of small-molecule pathway agonists.
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Affiliation(s)
- M Kyle Hadden
- Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Unit 3092, Storrs, CT 06269 (USA).
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53
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Nachtergaele S, Whalen DM, Mydock LK, Zhao Z, Malinauskas T, Krishnan K, Ingham PW, Covey DF, Siebold C, Rohatgi R. Structure and function of the Smoothened extracellular domain in vertebrate Hedgehog signaling. eLife 2013; 2:e01340. [PMID: 24171105 PMCID: PMC3809587 DOI: 10.7554/elife.01340] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 09/26/2013] [Indexed: 12/14/2022] Open
Abstract
The Hedgehog (Hh) signal is transduced across the membrane by the heptahelical protein Smoothened (Smo), a developmental regulator, oncoprotein and drug target in oncology. We present the 2.3 Å crystal structure of the extracellular cysteine rich domain (CRD) of vertebrate Smo and show that it binds to oxysterols, endogenous lipids that activate Hh signaling. The oxysterol-binding groove in the Smo CRD is analogous to that used by Frizzled 8 to bind to the palmitoleyl group of Wnt ligands and to similar pockets used by other Frizzled-like CRDs to bind hydrophobic ligands. The CRD is required for signaling in response to native Hh ligands, showing that it is an important regulatory module for Smo activation. Indeed, targeting of the Smo CRD by oxysterol-inspired small molecules can block signaling by all known classes of Hh activators and by clinically relevant Smo mutants. DOI:http://dx.doi.org/10.7554/eLife.01340.001.
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MESH Headings
- Animals
- Binding Sites
- Crystallography, X-Ray
- Embryo, Nonmammalian
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Gene Expression Regulation, Developmental
- Hedgehog Proteins/chemistry
- Hedgehog Proteins/genetics
- Hedgehog Proteins/metabolism
- Ligands
- Mice
- Models, Molecular
- Protein Binding
- Protein Structure, Secondary
- Protein Structure, Tertiary
- Receptors, G-Protein-Coupled/antagonists & inhibitors
- Receptors, G-Protein-Coupled/chemistry
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/genetics
- Recombinant Proteins/metabolism
- Signal Transduction
- Smoothened Receptor
- Sterols/chemistry
- Structure-Activity Relationship
- Zebrafish/genetics
- Zebrafish/growth & development
- Zebrafish/metabolism
- Zebrafish Proteins/antagonists & inhibitors
- Zebrafish Proteins/chemistry
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Sigrid Nachtergaele
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
| | - Daniel M Whalen
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Laurel K Mydock
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Zhonghua Zhao
- A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Kathiresan Krishnan
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Philip W Ingham
- A*STAR Institute of Molecular and Cell Biology, Singapore, Singapore
- Lee Kong Chian School of Medicine, Imperial College London/Nanyang Technological University, Singapore, Singapore
| | - Douglas F Covey
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, United States
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States
- Department of Medicine, Stanford University School of Medicine, Stanford, United States
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54
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Hokugo A, Sorice S, Parhami F, Yalom A, Li A, Zuk P, Jarrahy R. A novel oxysterol promotes bone regeneration in rabbit cranial bone defects. J Tissue Eng Regen Med 2013; 10:591-9. [PMID: 23997014 DOI: 10.1002/term.1799] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2013] [Revised: 06/20/2013] [Accepted: 07/15/2013] [Indexed: 12/16/2022]
Abstract
Bone morphogenetic proteins (BMPs) have played a central role in the development of regenerative therapies for bone reconstruction. However, the high cost and side-effect profile of BMPs limits their broad application. Oxysterols, naturally occurring products of cholesterol oxidation, are promising osteogenic agents alternative to BMPs. The osteogenic capacity of these non-toxic and relatively inexpensive molecules has been documented in rodent models. We studied the impact of Oxy49, a novel oxysterol analogue, on the osteogenic differentiation of rabbit bone marrow stromal cells (BMSCs). Moreover, we evaluated the capacity for in vivo bone regeneration with Oxy49 in rabbit cranial bone defects. We found that rabbit BMSCs treated with Oxy49 demonstrated differentiation along osteogenic pathways, and that complete bone regeneration occurred when cranial defects were treated with Oxy49. Collectively, these results demonstrate that Oxy49 has the ability to induce osteogenic differentiation in rabbit BMSCs with an efficacy comparable to that of BMP-2 and to promote significant bone regeneration in cranial defects. Oxysterols may be a viable novel agent in bone tissue engineering. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Akishige Hokugo
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Sarah Sorice
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Farhad Parhami
- Department of Medicine, David Geffen School of Medicine at UCLA, Center for the Health Sciences, Los Angeles, CA, USA
| | - Anisa Yalom
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Andrew Li
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Patricia Zuk
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Reza Jarrahy
- Division of Plastic and Reconstructive Surgery, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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55
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Machorro-Méndez I, Hernández-Mendoza A, Cardenia V, Rodriguez-Estrada M, Lercker G, Spinelli F, Cellini A, García H. Assessment of in vitro
removal of cholesterol oxidation products by Lactobacillus casei
ATCC334. Lett Appl Microbiol 2013; 57:443-50. [DOI: 10.1111/lam.12132] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2013] [Revised: 07/08/2013] [Accepted: 07/08/2013] [Indexed: 12/18/2022]
Affiliation(s)
| | | | - V. Cardenia
- Interdepartmental Centre for Agri-food Industrial Research; Alma Mater Studiorum-University of Bologna; Cesena (FC) Italy
| | - M.T. Rodriguez-Estrada
- Department of Agricultural and Food Sciences; Alma Mater Studiorum-University of Bologna; Bologna Italy
| | - G. Lercker
- Department of Agricultural and Food Sciences; Alma Mater Studiorum-University of Bologna; Bologna Italy
| | - F. Spinelli
- Department of Agricultural Sciences; Alma Mater Studiorum-University of Bologna; Bologna Italy
| | - A. Cellini
- Department of Agricultural Sciences; Alma Mater Studiorum-University of Bologna; Bologna Italy
| | - H.S. García
- UNIDA-Instituto Tecnológico de Veracruz; Veracruz México
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56
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In Vitro Study of a Novel Oxysterol for Osteogenic Differentiation on Rabbit Bone Marrow Stromal Cells. Plast Reconstr Surg 2013; 132:70e-80e. [DOI: 10.1097/prs.0b013e318290f460] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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57
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King WJ, Krebsbach PH. Cyclic-RGD peptides increase the adenoviral transduction of human mesenchymal stem cells. Stem Cells Dev 2013; 22:679-86. [PMID: 22958001 DOI: 10.1089/scd.2012.0379] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Human mesenchymal stem cells (hMSCs) have been extensively explored for drug delivery applications due to their safety, immunomodulatory properties, and ability to differentiate into new tissues. The experiments presented in this study were designed to determine peptide-based mechanisms to increase the adenoviral transduction of hMSCs for the purpose of improving their capacity as drug delivery vehicles. Specifically, we demonstrated that cyclic- RGD peptides increased the internalization of adenoviruses into MSCs. MSCs treated with cyclic-RGD peptides had a transduction efficiency of 76.6%±4%, which was significantly greater than the 23.5%±12.2% transduction efficiency of untreated stem cells (P<0.05). Blocking endocytosis with inhibitors of dynamin or actin polymerization decreased the cyclic-RGD-mediated increase in transduction efficiency. MSCs treated with cyclic-RGD and adenoviruses carrying the gene for bone morphogenetic protein-2 produced significantly greater concentrations of this growth factor compared to stem cells treated with only adenoviruses or adenoviruses cocultured with cyclic-RAD peptides. Furthermore, this stem cell-produced bone morphogenetic protein induced alkaline phosphatase expression in C2C12 cells indicating growth factor bioactivity. Taken together, these studies suggest that cyclic-RGD peptides could be used to increase the adenoviral transduction of hMSCs and increase their therapeutic potential.
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Affiliation(s)
- William J King
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, Ann Arbor, Michigan 48109-1078, USA
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58
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Soto-Rodríguez I, Alexander-Aguilera A, Zamudio-Pérez A, Camara-Contreras M, Hernandez-Diaz G, Garcia HS. Alteration of some inflammatory biomarkers by dietary oxysterols in rats. Inflammation 2013; 35:1302-7. [PMID: 22391743 DOI: 10.1007/s10753-012-9442-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Oxysterols are structurally similar to cholesterol, but are characterized by one or more additional oxygen-containing functional groups. These compounds are implicated in inflammation given their ability to cause irreversible damage to vascular cells. The aim of this study was to study the alteration of some inflammatory biomarkers in Wistar rats in response to dietary oxysterols. Eighteen rats were randomly divided into three groups of six rats each. A standard diet supplemented with 1% (w/w) pure cholesterol (Chol group) or 1% (w/w) of an oxidized cholesterol mixture (COPs group) was fed for 8 weeks. Blood serum was separated; abdominal, pericardial, and epididymal adipose tissue was removed carefully. The COPs subjects exhibited significant increase in blood pressure and serum triacylgycerols as well as increased body fat index and pericardic, abdominal, and epididymal adipose tissue. These effects were accompanied by elevated circulating levels of plasma high-sensitivity C-reactive protein, tumor necrosis factor alpha, and resistin. We suggest that dietary oxysterols have an important pro-inflammatory effect.
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Affiliation(s)
- Ida Soto-Rodríguez
- Facultad de Bioanálisis, Universidad Veracruzana, Carmen Serdán s/n, Col. Flores Magón, Veracruz, Ver, 91700, Mexico
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59
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Cucchi D, Occhione MA, Gulino A, De Smaele E. Hedgehog signaling pathway and its targets for treatment in basal cell carcinoma. J Exp Pharmacol 2012; 4:173-85. [PMID: 27186130 PMCID: PMC4863577 DOI: 10.2147/jep.s28553] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Basal cell carcinoma (BCC) of the skin is the most common type of cancer and accounts for up to 40% of all cancers in the US, with a growing incidence rate over recent decades in all developed countries. Surgery is curative for most patients, although it leaves unaesthetic scars, but those that develop locally advanced or metastatic BCC require different therapeutic approaches. Furthermore, patients with BCC present a high risk of developing additional tumors. The increasing economic burden and the morbidity of BCC render primary interest in the development of targeted treatments for this disease. Among the molecular signals involved in the development of BCC, the critical role of the morphogenetic Hedgehog (Hh) pathway has become evident. This pathway is found altered and activated in almost all BCCs, both sporadic and inherited. Given the centrality of the Hh pathway in the pathophysiology of BCC, the primary efforts to identify molecular targets for the topical or systemic treatment of this cancer have focused on the Hh components. Several Hh inhibitors have been so far identified - from the first identified natural cyclopamine to the recently Food and Drug Administration-approved synthetic vismodegib - most of which target the Hh receptor Smoothened (either its function or its translocation to the primary cilium). Other molecules await further characterization (bisamide compounds), while drugs currently approved for other diseases such as itraconazole (an antimicotic agent) and vitamin D3 have been tested on BCC with encouraging results. The outcomes of the numerous ongoing clinical trials are expected to expand the field in the very near future. Further research is needed to obtain drugs targeting downstream components of the Hh pathway (eg, Gli) or to exploit combinatorial therapies (eg, with phosphatidylinositol 3-kinase inhibitors or retinoids) in order to overcome potential drug resistance.
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Affiliation(s)
- Danilo Cucchi
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
| | | | - Alberto Gulino
- Department of Molecular Medicine, Sapienza University of Rome, Rome, Italy; Center of Life NanoScience @ La Sapienza, Istituto Italiano di Tecnologia, Rome, Italy
| | - Enrico De Smaele
- Department of Experimental Medicine, Sapienza University of Rome, Rome, Italy
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60
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Corman A, DeBerardinis AM, Hadden MK. Structure-activity relationships for side chain oxysterol agonists of the hedgehog signaling pathway. ACS Med Chem Lett 2012; 3:828-33. [PMID: 24900386 DOI: 10.1021/ml300192k] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Accepted: 08/28/2012] [Indexed: 01/20/2023] Open
Abstract
Oxysterols (OHCs) are byproducts of cholesterol oxidation that are known to activate the Hedeghog (Hh) signaling pathway. While OHCs that incorporate hydroxyl groups throughout the scaffold are known, those that act as agonists of Hh signaling primarily contain a single hydroxyl on the alkyl side chain. We sought to further explore how side chain hydroxylation patterns affect oxysterol-mediated Hh activation, by performing a structure-activity relationship study on a series of synthetic OHCs. The most active analogue, 23(R)-OHC (35), demonstrated potent activation of Hh signaling in two Hh-dependent cell lines (EC50 values 0.54-0.65 μM). In addition, OHC 35 was approximately 3-fold selective for the Hh pathway as compared to the liver X receptor, a nuclear receptor that is also activated by endogenous OHCs. Finally, 35 induced osteogenic differentiation and osteoblast formation in cultured cells, indicating functional agonism of the Hh pathway.
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Affiliation(s)
- Audrey Corman
- Department
of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Unit 3092, Storrs, Connecticut 06269-3092,
United States
| | - Albert M. DeBerardinis
- Department
of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Unit 3092, Storrs, Connecticut 06269-3092,
United States
| | - M. Kyle Hadden
- Department
of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Unit 3092, Storrs, Connecticut 06269-3092,
United States
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61
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Zhou Y, Robciuc MR, Wabitsch M, Juuti A, Leivonen M, Ehnholm C, Yki-Järvinen H, Olkkonen VM. OSBP-related proteins (ORPs) in human adipose depots and cultured adipocytes: evidence for impacts on the adipocyte phenotype. PLoS One 2012; 7:e45352. [PMID: 23028956 PMCID: PMC3448648 DOI: 10.1371/journal.pone.0045352] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2012] [Accepted: 08/15/2012] [Indexed: 01/28/2023] Open
Abstract
Oxysterol-binding protein (OSBP) homologues, ORPs, are implicated in lipid homeostatic control, vesicle transport, and cell signaling. We analyzed here the quantity of ORP mRNAs in human subcutaneous (s.c.) and visceral adipose depots, as well as in the Simpson-Golabi-Behmel syndrome (SGBS) adipocyte cell model. All of the ORP mRNAs were present in the s.c and visceral adipose tissues, and the two depots shared an almost identical ORP mRNA expression pattern. SGBS adipocytes displayed a similar pattern, suggesting that the adipose tissue ORP expression pattern mainly derives from adipocytes. During SGBS cell adipogenic differentiation, ORP2, ORP3, ORP4, ORP7, and ORP8 mRNAs were down-regulated, while ORP11 was induced. To assess the impacts of ORPs on adipocyte differentiation, ORP3 and ORP8, proteins down-regulated during adipogenesis, were overexpressed in differentiating SGBS adipocytes, while ORP11, a protein induced during adipogenesis, was silenced. ORP8 overexpression resulted in reduced expression of the aP2 mRNA, while down-regulation of adiponectin and aP2 was observed in ORP11 silenced cells. Furthermore, ORP8 overexpression or silencing of ORP11 markedly decreased cellular triglyceride storage. These data identify the patterns of ORP expression in human adipose depots and SGBS adipocytes, and provide the first evidence for a functional impact of ORPs on the adipocyte phenotype.
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Affiliation(s)
- You Zhou
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
| | - Marius R. Robciuc
- National Institute for Health and Welfare, Public Health Genomics Unit, Helsinki, Finland
| | - Martin Wabitsch
- Division of Paediatric Endocrinology and Diabetes, Department of Paediatrics and Adolescent Medicine, University of Ulm, Ulm, Germany
| | - Anne Juuti
- Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Marja Leivonen
- Department of Surgery, Helsinki University Central Hospital, Helsinki, Finland
| | - Christian Ehnholm
- National Institute for Health and Welfare, Public Health Genomics Unit, Helsinki, Finland
| | - Hannele Yki-Järvinen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Department of Medicine, University of Helsinki, Helsinki, Finland
| | - Vesa M. Olkkonen
- Minerva Foundation Institute for Medical Research, Helsinki, Finland
- Institute of Biomedicine, Anatomy, University of Helsinki, Helsinki, Finland
- * E-mail:
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62
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Stappenbeck F, Xiao W, Epperson M, Riley M, Priest A, Huang D, Nguyen K, Jung ME, Thies RS, Farouz F. Novel oxysterols activate the Hedgehog pathway and induce osteogenesis. Bioorg Med Chem Lett 2012; 22:5893-7. [PMID: 22901899 DOI: 10.1016/j.bmcl.2012.07.073] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 07/16/2012] [Accepted: 07/20/2012] [Indexed: 12/16/2022]
Abstract
Localized induction of bone formation is essential during orthopedic procedures that involve skeletal repair, such as surgical treatment of non-union bone fractures and degenerative disk disease. Herein we disclose the synthesis and biological evaluation of novel oxysterol derivatives designed as anabolic bone growth agents. Structure-activity relationship studies of oxysterol 4 have identified analogues such as 18, 21 and 30. These new analogues are characterized by higher potency in an osteoblast differentiation assay and/or by increased metabolic stability in human liver microsomes. Oxysterols 4, 18 and 21 were evaluated in vivo in a rat spinal fusion model.
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Affiliation(s)
- Frank Stappenbeck
- Fate Therapeutics, 3535 General Atomics Court, Suite 200, San Diego, CA 92121, USA.
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63
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Oxysterols and their cellular effectors. Biomolecules 2012; 2:76-103. [PMID: 24970128 PMCID: PMC4030866 DOI: 10.3390/biom2010076] [Citation(s) in RCA: 126] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 02/03/2012] [Accepted: 02/07/2012] [Indexed: 11/23/2022] Open
Abstract
Oxysterols are oxidized 27-carbon cholesterol derivatives or by-products of cholesterol biosynthesis, with a spectrum of biologic activities. Several oxysterols have cytotoxic and pro-apoptotic activities, the ability to interfere with the lateral domain organization, and packing of membrane lipids. These properties may account for their suggested roles in the pathology of diseases such as atherosclerosis, age-onset macular degeneration and Alzheimer’s disease. Oxysterols also have the capacity to induce inflammatory responses and play roles in cell differentiation processes. The functions of oxysterols as intermediates in the synthesis of bile acids and steroid hormones, and as readily transportable forms of sterol, are well established. Furthermore, their actions as endogenous regulators of gene expression in lipid metabolism via liver X receptors and the Insig (insulin-induced gene) proteins have been investigated in detail. The cytoplasmic oxysterol-binding protein (OSBP) homologues form a group of oxysterol/cholesterol sensors that has recently attracted a lot of attention. However, their mode of action is, as yet, poorly understood. Retinoic acid receptor-related orphan receptors (ROR) α and γ, and Epstein-Barr virus induced gene 2 (EBI2) have been identified as novel oxysterol receptors, revealing new physiologic oxysterol effector mechanisms in development, metabolism, and immunity, and evoking enhanced interest in these compounds in the field of biomedicine.
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64
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Oxysterols are allosteric activators of the oncoprotein Smoothened. Nat Chem Biol 2012; 8:211-20. [PMID: 22231273 PMCID: PMC3262054 DOI: 10.1038/nchembio.765] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 11/03/2011] [Indexed: 12/13/2022]
Abstract
Oxysterols are a class of endogenous signaling molecules that can activate the Hedgehog pathway, which has critical roles in development, regeneration and cancer. However, it has been unclear how oxysterols influence Hedgehog signaling, including whether their effects are mediated through a protein target or indirectly through effects on membrane properties. To answer this question, we synthesized the enantiomer and an epimer of the most potent oxysterol, 20(S)-hydroxycholesterol. Using these molecules, we show that the effects of oxysterols on Hedgehog signaling are exquisitely stereoselective, consistent with the hypothesis that they function through a specific protein target. We present several lines of evidence that this protein target is the seven-pass transmembrane protein Smoothened, a major drug target in oncology. Our work suggests that these enigmatic sterols, which have multiple effects on cell physiology, may act as ligands for signaling receptors and provides a generally applicable framework for probing sterol signaling mechanisms.
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65
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Park BH, Song KJ, Yoon SJ, Park HS, Jang KY, Zhou L, Lee SY, Lee KB, Kim JR. Acceleration of spinal fusion using COMP-angiopoietin 1 with allografting in a rat model. Bone 2011; 49:447-54. [PMID: 21658484 DOI: 10.1016/j.bone.2011.05.020] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 05/12/2011] [Accepted: 05/22/2011] [Indexed: 11/20/2022]
Abstract
INTRODUCTION Allografting has become widely available for the elimination of morbidity due to autogenous bone grafting procedures for spinal fusion. Enhancement of stable bone formation could facilitate this procedure. COMP-Ang1 is a recombinant chimeric protein of angiopoietin-1 that induces angiogenesis and vascular enlargement. We investigated the osteogenic potential of COMP-Ang1 for spinal fusion with allograft based on the enhancement of angiogenesis. METHODS Sixty Sprague-Dawley rats underwent bilateral posterior and posterolateral arthrodesis with allograft at L3-4 and L4-5. The animals were divided into three groups (n=20 each): (1) no treatment (sham group); (2) the bovine serum albumin-impregnated collagen sponge group (BSA group); 3) the COMP-Ang1-impregnated collagen sponge group (COMP-Ang1 group). Animals were sacrificed at six weeks for evaluation of spinal fusion using manual palpation, radiographs, and biomechanical and histomorphometric assessments. Total RNA was prepared from the fusion site and analyzed for osteogenic marker protein expression using RT-PCR analysis. RESULTS The fusion rates determined by manual palpation were 38.9% in the sham group, 42.1% in the BSA group, and 89.5% in the COMP-Ang1 group. Optical density of fusion masses in the COMP-Ang1 group was significantly higher than those in the sham and BSA groups (p<0.001). Total bone volume was significantly higher in the COMP-Ang1 group than in the sham and BSA groups (p<0.001). The mechanical strength was significantly greater in the COMP-Ang1 group than in the sham and BSA groups (p<0.01). Histologically, the fusion site of the COMP-Ang1 group showed a larger number of reactive bones compared with those in the BSA and sham groups. Immunostaining of endothelial cells for factor VIII revealed that COMP-Ang1 group showed higher levels of vascularity in the fusion site. Runt-related transcription factor 2 and its target genes were significantly up-regulated in the COMP-Ang1 group. CONCLUSIONS COMP-Ang1 induced radiologically and histologically demonstrable active osteogenesis by promoting angiogenesis in spinal fusions. It was concluded that COMP-Ang1 enhances spinal fusion and hence the strength of the fusion.
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Affiliation(s)
- Byung-Hyun Park
- Department of Biochemistry, Medical School and Research Institute for Endocrine Sciences, Chonbuk National University, Jeonju, Jeonbuk, 561-756, Republic of Korea
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