1
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Mulhall EM, Gharpure A, Lee RM, Dubin AE, Aaron JS, Marshall KL, Spencer KR, Reiche MA, Henderson SC, Chew TL, Patapoutian A. Direct observation of the conformational states of PIEZO1. Nature 2023; 620:1117-1125. [PMID: 37587339 PMCID: PMC10468401 DOI: 10.1038/s41586-023-06427-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Accepted: 07/11/2023] [Indexed: 08/18/2023]
Abstract
PIEZOs are mechanosensitive ion channels that convert force into chemoelectric signals1,2 and have essential roles in diverse physiological settings3. In vitro studies have proposed that PIEZO channels transduce mechanical force through the deformation of extensive blades of transmembrane domains emanating from a central ion-conducting pore4-8. However, little is known about how these channels interact with their native environment and which molecular movements underlie activation. Here we directly observe the conformational dynamics of the blades of individual PIEZO1 molecules in a cell using nanoscopic fluorescence imaging. Compared with previous structural models of PIEZO1, we show that the blades are significantly expanded at rest by the bending stress exerted by the plasma membrane. The degree of expansion varies dramatically along the length of the blade, where decreased binding strength between subdomains can explain increased flexibility of the distal blade. Using chemical and mechanical modulators of PIEZO1, we show that blade expansion and channel activation are correlated. Our findings begin to uncover how PIEZO1 is activated in a native environment. More generally, as we reliably detect conformational shifts of single nanometres from populations of channels, we expect that this approach will serve as a framework for the structural analysis of membrane proteins through nanoscopic imaging.
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Affiliation(s)
- Eric M Mulhall
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Anant Gharpure
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Rachel M Lee
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Adrienne E Dubin
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Jesse S Aaron
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Kara L Marshall
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Kathryn R Spencer
- Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA
| | - Michael A Reiche
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Scott C Henderson
- Department of Molecular Medicine, Scripps Research, La Jolla, CA, USA
| | - Teng-Leong Chew
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Ardem Patapoutian
- Howard Hughes Medical Institute, Department of Neuroscience, Dorris Neuroscience Center, Scripps Research, La Jolla, CA, USA.
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2
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Mulhall EM, Lee R, Dubin AE, Aaron J, Reiche M, Gharpure A, Marshall K, Spencer K, Henderson SC, Chew TL, Patapoutian A. Direct observation of Piezo1 conformational states. Biophys J 2023; 122:90a. [PMID: 36785079 DOI: 10.1016/j.bpj.2022.11.685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023] Open
Affiliation(s)
- Eric M Mulhall
- Department of Neuroscience, Scripps Research, San Diego, CA, USA
| | - Rachel Lee
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Adrienne E Dubin
- Department of Neuroscience, Scripps Research, San Diego, CA, USA
| | - Jesse Aaron
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Michael Reiche
- Advanced Imaging Center, Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
| | - Anant Gharpure
- Department of Neuroscience, Scripps Research, San Diego, CA, USA
| | - Kara Marshall
- Department of Neuroscience, Scripps Research, San Diego, CA, USA
| | - Kathryn Spencer
- Department of Neuroscience, Scripps Research, San Diego, CA, USA
| | - Scott C Henderson
- Department of Molecular Medicine, Scripps Research, San Diego, CA, USA
| | - Teng-Leong Chew
- Howard Hughes Medical Institute Janelia Research Campus, Ashburn, VA, USA
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3
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Johnson JL, Meneses-Salas E, Ramadass M, Monfregola J, Rahman F, Carvalho Gontijo R, Kiosses WB, Pestonjamasp K, Allen D, Zhang J, Osborne DG, Zhu YP, Wineinger N, Askari K, Chen D, Yu J, Henderson SC, Hedrick CC, Ursini MV, Grinstein S, Billadeau DD, Catz SD. Differential dysregulation of granule subsets in WASH-deficient neutrophil leukocytes resulting in inflammation. Nat Commun 2022; 13:5529. [PMID: 36130971 PMCID: PMC9492659 DOI: 10.1038/s41467-022-33230-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 09/08/2022] [Indexed: 11/09/2022] Open
Abstract
Dysregulated secretion in neutrophil leukocytes associates with human inflammatory disease. The exocytosis response to triggering stimuli is sequential; gelatinase granules modulate the initiation of the innate immune response, followed by the release of pro-inflammatory azurophilic granules, requiring stronger stimulation. Exocytosis requires actin depolymerization which is actively counteracted under non-stimulatory conditions. Here we show that the actin nucleator, WASH, is necessary to maintain azurophilic granules in their refractory state by granule actin entrapment and interference with the Rab27a-JFC1 exocytic machinery. On the contrary, gelatinase granules of WASH-deficient neutrophil leukocytes are characterized by decreased Rac1, shortened granule-associated actin comets and impaired exocytosis. Rac1 activation restores exocytosis of these granules. In vivo, WASH deficiency induces exacerbated azurophilic granule exocytosis, inflammation, and decreased survival. WASH deficiency thus differentially impacts neutrophil granule subtypes, impairing exocytosis of granules that mediate the initiation of the neutrophil innate response while exacerbating pro-inflammatory granule secretion.
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Affiliation(s)
- Jennifer L Johnson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Elsa Meneses-Salas
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Mahalakshmi Ramadass
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jlenia Monfregola
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
- Telethon Institute of Genetics and Medicine (TIGEM), Via Campi Flegrei 34, 80078, Pozzuoli, Naples, Italy
| | - Farhana Rahman
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | | | - William B Kiosses
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Kersi Pestonjamasp
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Dale Allen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Jinzhong Zhang
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Douglas G Osborne
- The Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Yanfang Peipei Zhu
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, CA, USA
| | - Nathan Wineinger
- Research Translational Institute, Statistics, The Scripps Research Institute, La Jolla, CA, USA
| | - Kasra Askari
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Danni Chen
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Juan Yu
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Scott C Henderson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Catherine C Hedrick
- Division of Inflammation Biology, La Jolla Institute for Immunology, La Jolla, CA, USA
| | | | - Sergio Grinstein
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Daniel D Billadeau
- The Division of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Sergio D Catz
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA.
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4
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Deng Y, Hammond JA, Pauszek R, Ozog S, Chai I, Rabuck-Gibbons J, Lamichhane R, Henderson SC, Millar DP, Torbett BE, Williamson JR. Discrimination between Functional and Non-functional Cellular Gag Complexes involved in HIV-1 Assembly. J Mol Biol 2021; 433:166842. [PMID: 33539875 DOI: 10.1016/j.jmb.2021.166842] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 01/18/2021] [Accepted: 01/20/2021] [Indexed: 02/06/2023]
Abstract
HIV-1 Gag and Gag-Pol are responsible for viral assembly and maturation and represent a major paradigm for enveloped virus assembly. Numerous intracellular Gag-containing complexes (GCCs) have been identified in cellular lysates using sucrose gradient ultracentrifugation. While these complexes are universally present in Gag-expressing cells, their roles in virus assembly are not well understood. Here we demonstrate that most GCC species are predominantly comprised of monomeric or dimeric Gag molecules bound to ribosomal complexes, and as such, are not on-pathway intermediates in HIV assembly. Rather, these GCCs represent a population of Gag that is not yet functionally committed for incorporation into a viable virion precursor. We hypothesize that these complexes act as a reservoir of monomeric Gag that can incorporate into assembling viruses, and serve to mitigate non-specific intracellular Gag oligomerization. We have identified a subset of large GCC complexes, comprising more than 20 Gag molecules, that may be equivalent to membrane-associated puncta previously shown to be bona fide assembling-virus intermediates. This work provides a clear rationale for the existence of diverse GCCs, and serves as the foundation for characterizing on-pathway intermediates early in virus assembly.
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Affiliation(s)
- Yisong Deng
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - John A Hammond
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Raymond Pauszek
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Stosh Ozog
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Ilean Chai
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Jessica Rabuck-Gibbons
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Rajan Lamichhane
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Scott C Henderson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - David P Millar
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - Bruce E Torbett
- Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037, United States
| | - James R Williamson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA 92037, United States; Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037, United States; The Skaggs Institute of Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, United States.
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5
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Saleh T, Tyutyunyk-Massey L, Murray GF, Alotaibi MR, Kawale AS, Elsayed Z, Henderson SC, Yakovlev V, Elmore LW, Toor A, Harada H, Reed J, Landry JW, Gewirtz DA. Abstract 901: Elimination of senescent tumor cells by ABT263 interferes with proliferative recovery and provides a two-hit therapeutic approach. Cancer Res 2019. [DOI: 10.1158/1538-7445.am2019-901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Senescence represents a fundamental response to cancer therapy. Accumulating senescent cells contribute to the deleterious outcomes of cancer therapy including cancer relapse, effects that may be largely mediated by the Senescence-Associated Secretory Phenotype (SASP). In this work, we show that tumor cells induced into senescence by etoposide retain proliferative capacity based on their capacity to generate proliferating colonies in culture as well as giving rise to viable tumors in vivo. Using a flow cytometry-based enrichment approach based on enlarged size and expression of Senescence-Associated β-galactosidase (SA-β-gal), we were able to utilize real time imaging to establish the re-emergence of non-small cell lung cancer cells from senescence-based arrest and the generation or proliferating daughter cells (i.e. self-renewal). Moreover, we implemented High-Speed Live-Cell Interferometry (HSLCI) to provide a single-cell lineage tracking of dividing senescent cells. The recovery from senescence was accompanied by resolution of several senescence-associated hallmarks, specifically SA-β-gal activity, p21Waf1/Cip1 and several components of the SASP (IL-1β, IL-6 and CXCL1). Our data suggests that Therapy-Induced Senescence (TIS) may ultimately be a transient process in that at least a subpopulation of tumor cells can recover proliferative capacity. We further demonstrate that the senolytic agent, ABT263, which has been shown to eliminate senescent cells from aging-related animal models can also eliminate senescent tumor cells that persistent after exposure to chemotherapy by shifting the response towards apoptotic cell death. Furthermore, sequential administration of ABT263 interferes with the ability of tumor cells induced into senescence by chemotherapy to recover growth potential. These studies suggest that senescent tumor cells can potentially contribute to cancer relapse by acquiring proliferative properties. The use of senolytic agents after induction of senescence by conventional or targeted therapies allows for the clearance of residual (possibly dormant) senescent tumor cells, which could serve to suppress disease recurrence and cancer mortality.
Citation Format: Tareq Saleh, Liliya Tyutyunyk-Massey, Graeme F. Murray, Moureq R. Alotaibi, Ajinkya S. Kawale, Zeinab Elsayed, Scott C. Henderson, Vasily Yakovlev, Lynne W. Elmore, Amir Toor, Hisashi Harada, Jason Reed, Joseph W. Landry, David A. Gewirtz. Elimination of senescent tumor cells by ABT263 interferes with proliferative recovery and provides a two-hit therapeutic approach [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 901.
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Affiliation(s)
- Tareq Saleh
- 1Virginia Commonwealth University, Richmond, VA
| | | | | | | | | | | | | | | | | | - Amir Toor
- 1Virginia Commonwealth University, Richmond, VA
| | | | - Jason Reed
- 1Virginia Commonwealth University, Richmond, VA
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6
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Saleh T, Tyutyunyk-Massey L, Murray GF, Alotaibi MR, Kawale AS, Elsayed Z, Henderson SC, Yakovlev V, Elmore LW, Toor A, Harada H, Reed J, Landry JW, Gewirtz DA. Tumor cell escape from therapy-induced senescence. Biochem Pharmacol 2018; 162:202-212. [PMID: 30576620 DOI: 10.1016/j.bcp.2018.12.013] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Accepted: 12/17/2018] [Indexed: 01/10/2023]
Abstract
H460 non-small cell lung, HCT116 colon and 4T1 breast tumor cell lines induced into senescence by exposure to either etoposide or doxorubicin were able to recover proliferative capacity both in mass culture and when enriched for the senescence-like phenotype by flow cytometry (based on β-galactosidase staining and cell size, and a senescence-associated reporter, BTG1-RFP). Recovery was further established using both real-time microscopy and High-Speed Live-Cell Interferometry (HSLCI) and was shown to be accompanied by the attenuation of the Senescence-Associated Secretory Phenotype (SASP). Cells enriched for the senescence-like phenotype were also capable of forming tumors when implanted in both immunodeficient and immunocompetent mice. As chemotherapy-induced senescence has been identified in patient tumors, our results suggest that certain senescence-like phenotypes may not reflect a terminal state of growth arrest, as cells that recover with self-renewal capacity may ultimately contribute to disease recurrence.
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Affiliation(s)
- Tareq Saleh
- Departments of Pharmacology & Toxicology and Medicine, and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
| | - Liliya Tyutyunyk-Massey
- Departments of Pharmacology & Toxicology and Medicine, and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States
| | - Graeme F Murray
- Department of Physics, Virginia Commonwealth University, Richmond, VA, United States
| | | | - Ajinkya S Kawale
- Departments of Pharmacology & Toxicology and Medicine, and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States; Department of Molecular Biology and Genetics, Virginia Commonwealth University, Richmond, VA, United States
| | - Zeinab Elsayed
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, United States
| | - Scott C Henderson
- Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, United States
| | - Vasily Yakovlev
- Department of Radiation Oncology, Virginia Commonwealth University, Richmond, VA, United States
| | - Lynne W Elmore
- Department of Extramural Research, American Cancer Society, Atlanta, GA, United States
| | - Amir Toor
- Department of Internal Medicine, Virginia Commonwealth University, Richmond, VA, United States
| | - Hisashi Harada
- Philips Institute for Oral Health Research, School of Dentistry, Virginia Commonwealth University, Richmond, VA, United States
| | - Jason Reed
- Department of Physics, Virginia Commonwealth University, Richmond, VA, United States
| | - Joseph W Landry
- Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, VA, United States
| | - David A Gewirtz
- Departments of Pharmacology & Toxicology and Medicine, and Massey Cancer Center, Virginia Commonwealth University, Richmond, VA, United States.
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7
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Saleh T, Alotaibi MR, Kyte SL, Cudjoe EK, Kawale A, Xu J, Elsayed Z, Landry JW, Henderson SC, Yakovlev V, Elmore LW, Gewirtz DA. Abstract 459: Therapy-induced senescence is reversible in vitro and in vivo. Cancer Res 2018. [DOI: 10.1158/1538-7445.am2018-459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
While cellular senescence has long been recognized as an irreversible form of growth arrest, evidence in the literature has suggested that subpopulations of senescent tumor cells may retain proliferative capacity. To directly address this question, H460 non-small cell lung cancer cells induced into senescence by exposure to etoposide, and enriched based on β-galactosidase staining and size, were shown to recover reproductive capacity, which was accompanied by resolution of the DNA-damage-response (downregulation of p53 and p21Waf1/Cip1 induction), attenuation of the senescence-associated secretory phenotype (SASP) as well as downregulation of miRNA34 expression and an increase in c-myc. The senescence-enriched lung cancer cells were also capable of tumor growth upon transplantation into immunodeficient mice. Re-emergence from etoposide-induced senescence was also observed using HCT116 colon cancer cells, as evidenced by concomitant downregulation of a senescence-associated reporter (BTG1-RFP). Collectively, these findings indicate that therapy-induced senescence (TIS) may ultimately be a transient process in that at least a subpopulation of tumor cells can resume proliferation. We propose that some forms of tumor dormancy that lead to disease recurrence may reflect cells that enter into and ultimately escape from senescence.
Citation Format: Tareq Saleh, Moureq R. Alotaibi, Sarah L. Kyte, Emmanuel K. Cudjoe, Ajinkya Kawale, Jingwen Xu, Zeinab Elsayed, Joseph W. Landry, Scott C. Henderson, Vasily Yakovlev, Lynne W. Elmore, David A. Gewirtz. Therapy-induced senescence is reversible in vitro and in vivo [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 459.
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Affiliation(s)
| | | | | | | | | | - Jingwen Xu
- 3Shenyang Pharmaceutical University, Richmond, China
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8
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Xu X, Zhang A, Halquist MS, Yuan X, Henderson SC, Dewey WL, Li PL, Li N, Zhang F. Simvastatin promotes NPC1-mediated free cholesterol efflux from lysosomes through CYP7A1/LXRα signalling pathway in oxLDL-loaded macrophages. J Cell Mol Med 2016; 21:364-374. [PMID: 27629819 PMCID: PMC5264135 DOI: 10.1111/jcmm.12970] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/09/2016] [Indexed: 01/05/2023] Open
Abstract
Statins, 3‐hydroxyl‐3‐methylglutaryl coenzyme A reductase inhibitors, are the first‐line medications prescribed for the prevention and treatment of coronary artery diseases. The efficacy of statins has been attributed not only to their systemic cholesterol‐lowering actions but also to their pleiotropic effects that are unrelated to cholesterol reduction. These pleiotropic effects have been increasingly recognized as essential in statins therapy. This study was designed to investigate the pleiotropic actions of simvastatin, one of the most commonly prescribed statins, on macrophage cholesterol homeostasis with a focus on lysosomal free cholesterol egression. With simultaneous nile red and filipin staining, analysis of confocal/multi‐photon imaging demonstrated that simvastatin markedly attenuated unesterified (free) cholesterol buildup in macrophages loaded with oxidized low‐density lipoprotein but had little effect in reducing the sizes of cholesteryl ester‐containing lipid droplets; the reduction in free cholesterol was mainly attributed to decreases in lysosome‐compartmentalized cholesterol. Functionally, the egression of free cholesterol from lysosomes attenuated pro‐inflammatory cytokine secretion. It was determined that the reduction of lysosomal free cholesterol buildup by simvastatin was due to the up‐regulation of Niemann‐Pick C1 (NPC1), a lysosomal residing cholesterol transporter. Moreover, the enhanced enzymatic production of 7‐hydroxycholesterol by cytochrome P450 7A1 and the subsequent activation of liver X receptor α underscored the up‐regulation of NPC1. These findings reveal a novel pleiotropic effect of simvastatin in affecting lysosomal cholesterol efflux in macrophages and the associated significance in the treatment of atherosclerosis.
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Affiliation(s)
- Xiaoyang Xu
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA.,Department of Physiology, Guangzhou Medical University, Guangzhou, China
| | - Aolin Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Matthew S Halquist
- Department of Pharmaceutics, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Xinxu Yuan
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Scott C Henderson
- Department of Anatomy & Neurobiology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - William L Dewey
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Pin-Lan Li
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Ningjun Li
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
| | - Fan Zhang
- Department of Pharmacology & Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA, USA
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9
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Li W, Mukherjee A, Wu J, Zhang L, Teves ME, Li H, Nambiar S, Henderson SC, Horwitz AR, Strauss JF, Fang X, Zhang Z. Sperm Associated Antigen 6 (SPAG6) Regulates Fibroblast Cell Growth, Morphology, Migration and Ciliogenesis. Sci Rep 2015; 5:16506. [PMID: 26585507 PMCID: PMC4653743 DOI: 10.1038/srep16506] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 10/15/2015] [Indexed: 11/09/2022] Open
Abstract
Mammalian Spag6 is the orthologue of Chlamydomonas PF16, which encodes a protein localized in the axoneme central apparatus, and regulates flagella/cilia motility. Most Spag6-deficient mice are smaller in size than their littermates. Because SPAG6 decorates microtubules, we hypothesized that SPAG6 has other roles related to microtubule function besides regulating flagellar/cilia motility. Mouse embryonic fibroblasts (MEFs) were isolated from Spag6-deficient and wild-type embryos for these studies. Both primary and immortalized Spag6-deficient MEFs proliferated at a much slower rate than the wild-type MEFs, and they had a larger surface area. Re-expression of SPAG6 in the Spag6-deficient MEFs rescued the abnormal cell morphology. Spag6-deficient MEFs were less motile than wild-type MEFs, as shown by both chemotactic analysis and wound-healing assays. Spag6-deficient MEFs also showed reduced adhesion associated with a non-polarized F-actin distribution. Multiple centrosomes were observed in the Spag6-deficient MEF cultures. The percentage of cells with primary cilia was significantly reduced compared to the wild-type MEFs, and some Spag6-deficient MEFs developed multiple cilia. Furthermore, SPAG6 selectively increased expression of acetylated tubulin, a microtubule stability marker. The Spag6-deficient MEFs were more sensitive to paclitaxel, a microtubule stabilizer. Our studies reveal new roles for SPAG6 in modulation of cell morphology, proliferation, migration, and ciliogenesis.
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Affiliation(s)
- Wei Li
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Abir Mukherjee
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Jinhua Wu
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Ling Zhang
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298.,School of Public Health, Wuhan University of Science and Technology, Wuhan, Hubei 430065, China
| | - Maria E Teves
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Hongfei Li
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Shanti Nambiar
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Scott C Henderson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Alan R Horwitz
- Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA
| | - Jerome F Strauss
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298.,Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Xianjun Fang
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Zhibing Zhang
- Department of Obstetrics &Gynecology, Virginia Commonwealth University, Richmond, VA, 23298.,Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, VA, 23298
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10
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Baer ML, Henderson SC, Colello RJ. Elucidating the Role of Injury-Induced Electric Fields (EFs) in Regulating the Astrocytic Response to Injury in the Mammalian Central Nervous System. PLoS One 2015; 10:e0142740. [PMID: 26562295 PMCID: PMC4643040 DOI: 10.1371/journal.pone.0142740] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 10/25/2015] [Indexed: 12/22/2022] Open
Abstract
Injury to the vertebrate central nervous system (CNS) induces astrocytes to change their morphology, to increase their rate of proliferation, and to display directional migration to the injury site, all to facilitate repair. These astrocytic responses to injury occur in a clear temporal sequence and, by their intensity and duration, can have both beneficial and detrimental effects on the repair of damaged CNS tissue. Studies on highly regenerative tissues in non-mammalian vertebrates have demonstrated that the intensity of direct-current extracellular electric fields (EFs) at the injury site, which are 50-100 fold greater than in uninjured tissue, represent a potent signal to drive tissue repair. In contrast, a 10-fold EF increase has been measured in many injured mammalian tissues where limited regeneration occurs. As the astrocytic response to CNS injury is crucial to the reparative outcome, we exposed purified rat cortical astrocytes to EF intensities associated with intact and injured mammalian tissues, as well as to those EF intensities measured in regenerating non-mammalian vertebrate tissues, to determine whether EFs may contribute to the astrocytic injury response. Astrocytes exposed to EF intensities associated with uninjured tissue showed little change in their cellular behavior. However, astrocytes exposed to EF intensities associated with injured tissue showed a dramatic increase in migration and proliferation. At EF intensities associated with regenerating non-mammalian vertebrate tissues, these cellular responses were even more robust and included morphological changes consistent with a regenerative phenotype. These findings suggest that endogenous EFs may be a crucial signal for regulating the astrocytic response to injury and that their manipulation may be a novel target for facilitating CNS repair.
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Affiliation(s)
- Matthew L. Baer
- Department of Anatomy & Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Scott C. Henderson
- Department of Anatomy & Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Raymond J. Colello
- Department of Anatomy & Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia, United States of America
- * E-mail:
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11
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Jiang M, Zhang M, Henderson SC, Gea-Ny T. Probing the Trafficking Routes of KCNQ1 and KCNE1 After Their ER Exit. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.1081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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12
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Marmarou CR, Liang X, Abidi NH, Parveen S, Taya K, Henderson SC, Young HF, Filippidis AS, Baumgarten CM. Selective vasopressin-1a receptor antagonist prevents brain edema, reduces astrocytic cell swelling and GFAP, V1aR and AQP4 expression after focal traumatic brain injury. Brain Res 2014; 1581:89-102. [PMID: 24933327 DOI: 10.1016/j.brainres.2014.06.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 05/08/2014] [Accepted: 06/04/2014] [Indexed: 11/16/2022]
Abstract
A secondary and often lethal consequence of traumatic brain injury is cellular edema that we posit is due to astrocytic swelling caused by transmembrane water fluxes augmented by vasopressin-regulated aquaporin-4 (AQP4). We therefore tested whether vasopressin 1a receptor (V1aR) inhibition would suppress astrocyte AQP4, reduce astrocytic edema, and thereby diminish TBI-induced edematous changes. V1aR inhibition by SR49059 significantly reduced brain edema after cortical contusion injury (CCI) in rat 5h post-injury. Injured-hemisphere brain water content (n=6 animals/group) and astrocytic area (n=3/group) were significantly higher in CCI-vehicle (80.5±0.3%; 18.0±1.4 µm(2)) versus sham groups (78.3±0.1%; 9.5±0.9 µm(2)), and SR49059 blunted CCI-induced increases in brain edema (79.0±0.2%; 9.4±0.8µm(2)). CCI significantly up-regulated GFAP, V1aR and AQP4 protein levels and SR49059 suppressed injury induced up regulation (n=6/group). In CCI-vehicle, sham and CCI-SR49059 groups, GFAP was 1.58±0.04, 0.47±0.02, and 0.81±0.03, respectively; V1aR was 1.00±0.06, 0.45±0.05, and 0.46±0.09; and AQP4 was 2.03±0.34, 0.49±0.04, and 0.92±0.22. Confocal immunohistochemistry gave analogous results. In CCI-vehicle, sham and CCI-SR49059 groups, fluorescence intensity of GFAP was 349±38, 56±5, and 244±30, respectively, V1aR was 601±71, 117.8±14, and 390±76, and AQP4 was 818±117, 158±5, and 458±55 (n=3/group). The results support that edema was predominantly cellular following CCI and documented that V1aR inhibition with SR49059 suppressed injury-induced up regulation of GFAP, V1A and AQP4, blunting edematous changes. Our findings suggest V1aR inhibitors may be potential therapeutic tools to prevent cellular swelling and provide treatment for post-traumatic brain edema.
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Affiliation(s)
- Christina R Marmarou
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA; Department of Physiology and Biophysics, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA.
| | - Xiuyin Liang
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Naqeeb H Abidi
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Shanaz Parveen
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Keisuke Taya
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Scott C Henderson
- Department of Anatomy and Neurobiolog, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Harold F Young
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Aristotelis S Filippidis
- Department of Neurosurgery, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
| | - Clive M Baumgarten
- Department of Physiology and Biophysics, Virginia Commonwealth University, Medical College of Virginia Campus, Richmond, VA 23298, USA
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13
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Abstract
Fluorescence labeled oligonucleotides have a long history of being used to monitor nucleic acid transport and uptake. However, it is not known if the fluorescent moiety itself physically limits the number of pathways that can be used by the cell due to steric, hydrophobic, or other chemical characteristics. Here, we report a method for comparing the uptake kinetics of oligonucleotides labeled either with the fluorescent pteridine, 3-methyl-8-(2-deoxy-β-D-ribofuranosyl) isoxanthopterin (3MI), or the common fluorophore 5-carboxyfluorescein (5-FAM). We use a multiphoton microscopic technique to monitor nucleic acid uptake LLC-PK1, a pig renal tubular cell line that is known to have multiple uptake pathways. We find that the two fluorophores enter the cells at different rates, suggesting that choice of fluorescent moiety influences the uptake pathway used by a cell. Finally, we reconstituted an LLC-PK1 membrane channel that is selective for nucleic acids in planar lipid bilayers, and tested the ability of the labeled nucleic acids to permeate the channel. We find that 3MI, and not 5-FAM labeled oligonucleotides can traverse the plasma membrane through the channel. These results have implications for future studies aimed at delivering pteridine moieties to cells and for tracking nucleic acid transport into tissues.
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Affiliation(s)
- Justin A Costa
- Division of Nephrology, Department of Medicine, Mt. Sinai School of Medicine, New York, NY
| | - Edgar Leal-Pinto
- Department of Physiology and Biophysics, Virginia Commonwealth University Medical Center, Richmond, VA
| | - Scott C Henderson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University Medical Center, Richmond, VA
| | | | - Mary E Hawkins
- Laboratory of Receptor Biology and Gene Expression, NCI/NIH, Bethesda, MD
| | - Basil Hanss
- Division of Nephrology, Department of Medicine, Mt. Sinai School of Medicine, New York, NY
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14
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Wang Y, Zankov DP, Jiang M, Zhang M, Henderson SC, Tseng GN. [Ca2+]i elevation and oxidative stress induce KCNQ1 protein translocation from the cytosol to the cell surface and increase slow delayed rectifier (IKs) in cardiac myocytes. J Biol Chem 2013; 288:35358-71. [PMID: 24142691 DOI: 10.1074/jbc.m113.504746] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Our goals are to simultaneously determine the three-dimensional distribution patterns of KCNQ1 and KCNE1 in cardiac myocytes and to study the mechanism and functional implications for variations in KCNQ1/KCNE1 colocalization in myocytes. We monitored the distribution patterns of KCNQ1, KCNE1, and markers for subcellular compartments/organelles using immunofluorescence/confocal microscopy and confirmed the findings in ventricular myocytes by directly observing fluorescently tagged KCNQ1-GFP and KCNE1-dsRed expressed in these cells. We also monitored the effects of stress on KCNQ1-GFP and endoplasmic reticulum (ER) remodeling during live cell imaging. The data showed that 1) KCNE1 maintained a stable cell surface localization, whereas KCNQ1 exhibited variations in the cytosolic compartment (striations versus vesicles) and the degree of presence on the cell surface; 2) the degree of cell surface KCNQ1/KCNE1 colocalization was positively correlated with slow delayed rectifier (IKs) current density; 3) KCNQ1 and calnexin (an ER marker) shared a cytosolic compartment; and 4) in response to stress ([Ca(2+)]i elevation, oxidative overload, or AT1R stimulation), KCNQ1 exited the cytosolic compartment and trafficked to the cell periphery in vesicles. This was accompanied by partial ER fragmentation. We conclude that the cellular milieu regulates KCNQ1 distribution in cardiac myocytes and that stressful conditions can increase IKs by inducing KCNQ1 movement to the cell surface. This represents a hitherto unrecognized mechanism by which IKs fulfills its function as a repolarization reserve in ventricular myocytes.
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Affiliation(s)
- Yuhong Wang
- From the Department of Physiology and Biophysics and
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15
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Pomicter AD, Deloyht JM, Hackett AR, Purdie N, Sato-Bigbee C, Henderson SC, Dupree JL. Nfasc155H and MAG are specifically susceptible to detergent extraction in the absence of the myelin sphingolipid sulfatide. Neurochem Res 2013; 38:2490-502. [PMID: 24081651 DOI: 10.1007/s11064-013-1162-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 07/17/2013] [Accepted: 09/20/2013] [Indexed: 12/13/2022]
Abstract
Mice incapable of synthesizing the myelin lipid sulfatide form paranodes that deteriorate with age. Similar instability also occurs in mice that lack contactin, contactin-associated protein or neurofascin155 (Nfasc155), the proteins that cluster in the paranode and form the junctional complex that mediates myelin-axon adhesion. In contrast to these proteins, sulfatide has not been shown to be enriched in the paranode nor has a sulfatide paranodal binding partner been identified; thus, it remains unclear how the absence of sulfatide results in compromised paranode integrity. Using an in situ extraction procedure, it has been reported that the absence of the myelin sphingolipids, galactocerebroside and sulfatide, increased the susceptibility of Nfasc155 to detergent extraction. Here, employing a similar approach, we demonstrate that in the presence of galactocerebroside but in the absence of sulfatide Nfasc155 is susceptible to detergent extraction. Furthermore, we use this in situ approach to show that stable association of myelin-associated glycoprotein (MAG) with the myelin membrane is sulfatide dependent while the membrane associations of myelin/oligodendrocyte glycoprotein, myelin basic protein and cyclic nucleotide phosphodiesterase are sulfatide independent. These findings indicate that myelin proteins maintain their membrane associations by different mechanisms. Moreover, the myelin proteins that cluster in the paranode and require sulfatide mediate myelin-axon adhesion. Additionally, the apparent dependency on sulfatide for maintaining Nfasc155 and MAG associations is intriguing since the fatty acid composition of sulfatide is altered and paranodal ultrastructure is compromised in multiple sclerosis. Thus, our findings present a potential link between sulfatide perturbation and myelin deterioration in multiple sclerosis.
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Affiliation(s)
- A D Pomicter
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, 1101 E. Marshall Street, Richmond, VA, 23298, USA
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16
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Cepeda MS, Fife D, Chow W, Mastrogiovanni G, Henderson SC. Opioid Shopping Behavior: How Often, How Soon, Which Drugs, and What Payment Method. J Clin Pharmacol 2013; 53:112-7. [DOI: 10.1177/0091270012436561] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Accepted: 11/14/2011] [Indexed: 11/17/2022]
Affiliation(s)
| | - Daniel Fife
- Janssen Research & Development LLC; Titusville, NJ,; USA
| | - Wing Chow
- Janssen Research & Development LLC; Titusville, NJ,; USA
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17
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Teves ME, Zhang Z, Costanzo RM, Henderson SC, Corwin FD, Zweit J, Sundaresan G, Subler M, Salloum FN, Rubin BK, Strauss JF. Sperm-associated antigen-17 gene is essential for motile cilia function and neonatal survival. Am J Respir Cell Mol Biol 2013; 48:765-72. [PMID: 23418344 PMCID: PMC3727877 DOI: 10.1165/rcmb.2012-0362oc] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 01/16/2013] [Indexed: 11/24/2022] Open
Abstract
Primary ciliary dyskinesia (PCD), resulting from defects in cilia assembly or motility, is caused by mutations in a number of genes encoding axonemal proteins. PCD phenotypes are variable, and include recurrent respiratory tract infections, bronchiectasis, hydrocephaly, situs inversus, and male infertility. We generated knockout mice for the sperm-associated antigen-17 (Spag17) gene, which encodes a central pair (CP) protein present in the axonemes of cells with "9 + 2" motile cilia or flagella. The targeting of Spag17 resulted in a severe phenotype characterized by immotile nasal and tracheal cilia, reduced clearance of nasal mucus, profound respiratory distress associated with lung fluid accumulation and disruption of the alveolar epithelium, cerebral ventricular expansion consistent with emerging hydrocephalus, failure to suckle, and neonatal demise within 12 hours of birth. Ultrastructural analysis revealed the loss of one CP microtubule in approximately one quarter of tracheal cilia axonemes, an absence of a C1 microtubule projection, and other less frequent CP structural abnormalities. SPAG6 and SPAG16 (CP proteins that interact with SPAG17) were increased in tracheal tissue from SPAG17-deficient mice. We conclude that Spag17 plays a critical role in the function and structure of motile cilia, and that neonatal lethality is likely explained by impaired airway mucociliary clearance.
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Affiliation(s)
| | - Zhibing Zhang
- Department of Obstetrics and Gynecology
- Department of Biochemistry and Molecular Biology
| | | | | | | | - Jamal Zweit
- Department of Biochemistry and Molecular Biology
- Department of Radiology
| | | | | | - Fadi N. Salloum
- Pauley Heart Center, Division of Cardiology, Department of Internal Medicine, and
| | - Bruce K. Rubin
- Department of Physiology and Biophysics
- Department of Pediatrics, Virginia Commonwealth University, Richmond, Virginia
| | - Jerome F. Strauss
- Department of Obstetrics and Gynecology
- Department of Biochemistry and Molecular Biology
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18
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Colello RJ, Tozer J, Henderson SC. Confocal laser scanning microscopic photoconversion: a new method to stabilize fluorescently labeled cellular elements for electron microscopic analysis. ACTA ACUST UNITED AC 2013; Chapter 2:Unit2.15. [PMID: 23042499 DOI: 10.1002/0471142301.ns0215s58] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Photoconversion, the method by which a fluorescent dye is transformed into a stable, osmiophilic product that can be visualized by electron microscopy, is the most widely used method to enable the ultrastructural analysis of fluorescently labeled cellular structures. Nevertheless, the conventional method of photoconversion using widefield fluorescence microscopy requires long reaction times and results in low-resolution cell targeting. Accordingly, we have developed a photoconversion method that ameliorates these limitations by adapting confocal laser scanning microscopy to the procedure. We have found that this method greatly reduces photoconversion times, as compared to conventional wide field microscopy. Moreover, region-of-interest scanning capabilities of a confocal microscope facilitate the targeting of the photoconversion process to individual cellular or subcellular elements within a fluorescent field. This reduces the area of the cell exposed to light energy, thereby reducing the ultrastructural damage common to this process when widefield microscopes are employed.
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Affiliation(s)
- Raymond J Colello
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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19
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Abstract
Nuclei in the giant polyploid silk gland cells of Calpodes ethlius grow by endomitosis and can develop hundreds of branches during larval life. The shape of the these nuclei is characteristic for each region of the gland. We have found shape to be correlated with arrangement of the nuclear matrix. Scanning electron microscopy showed nuclear matrices with shapes similar to those of feulgen stained nuclei. Profiles of isolated matrices seen by transmission electron microscopy had filaments aligned parallel to the long axis of nuclear branches. DNA stained by Hoechst had a similar parallel alignment within the branches. Nuclear shape may be maintained by a small number of components, since electrophoretic analysis showed only a few abundant polypeptides in the matrix fraction. Silk gland nuclei have some of the same nuclear matrix antigens found in smaller, more regularly shaped, eukaryote nuclei.
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Affiliation(s)
- S C Henderson
- Department of Zoology, University of Western Ontario, London, Ontario, Canada, N6A 5B7
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20
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Abstract
Double-strand breaks (DSBs) are the most deleterious DNA lesions a cell can encounter. If left unrepaired, DSBs harbor great potential to generate mutations and chromosomal aberrations. To prevent this trauma from catalyzing genomic instability, it is crucial for cells to detect DSBs, activate the DNA damage response (DDR), and repair the DNA. When stimulated, the DDR works to preserve genomic integrity by triggering cell cycle arrest to allow for repair to take place or force the cell to undergo apoptosis. The predominant mechanisms of DSB repair occur through nonhomologous end-joining (NHEJ) and homologous recombination repair (HRR) (reviewed in). There are many proteins whose activities must be precisely orchestrated for the DDR to function properly. Herein, we describe a method for 2- and 3-dimensional (D) visualization of one of these proteins, 53BP1. The p53-binding protein 1 (53BP1) localizes to areas of DSBs by binding to modified histones, forming foci within 5-15 minutes. The histone modifications and recruitment of 53BP1 and other DDR proteins to DSB sites are believed to facilitate the structural rearrangement of chromatin around areas of damage and contribute to DNA repair. Beyond direct participation in repair, additional roles have been described for 53BP1 in the DDR, such as regulating an intra-S checkpoint, a G2/M checkpoint, and activating downstream DDR proteins. Recently, it was discovered that 53BP1 does not form foci in response to DNA damage induced during mitosis, instead waiting for cells to enter G1 before localizing to the vicinity of DSBs. DDR proteins such as 53BP1 have been found to associate with mitotic structures (such as kinetochores) during the progression through mitosis. In this protocol we describe the use of 2- and 3-D live cell imaging to visualize the formation of 53BP1 foci in response to the DNA damaging agent camptothecin (CPT), as well as 53BP1's behavior during mitosis. Camptothecin is a topoisomerase I inhibitor that primarily causes DSBs during DNA replication. To accomplish this, we used a previously described 53BP1-mCherry fluorescent fusion protein construct consisting of a 53BP1 protein domain able to bind DSBs. In addition, we used a histone H2B-GFP fluorescent fusion protein construct able to monitor chromatin dynamics throughout the cell cycle but in particular during mitosis. Live cell imaging in multiple dimensions is an excellent tool to deepen our understanding of the function of DDR proteins in eukaryotic cells.
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Affiliation(s)
- Jason M Beckta
- Department of Radiation Oncology, Virginia Commonwealth University, USA
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21
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Goehe RW, Di X, Sharma K, Bristol ML, Henderson SC, Valerie K, Rodier F, Davalos AR, Gewirtz DA. The autophagy-senescence connection in chemotherapy: must tumor cells (self) eat before they sleep? J Pharmacol Exp Ther 2012; 343:763-78. [PMID: 22927544 DOI: 10.1124/jpet.112.197590] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Exposure of MCF-7 breast tumor cells or HCT-116 colon carcinoma cells to clinically relevant concentrations of doxorubicin (Adriamycin; Farmitalia Research Laboratories, Milan, Italy) or camptothecin results in both autophagy and senescence. To determine whether autophagy is required for chemotherapy-induced senescence, reactive oxygen generation induced by Adriamycin was suppressed by N-acetyl cysteine and glutathione, and the induction of ataxia telangiectasia mutated, p53, and p21 was modulated pharmacologically and/or genetically. In all cases, autophagy and senescence were collaterally suppressed. The close association between autophagy and senescence indicated by these experiments reflects their collateral regulation via common signaling pathways. The potential relationship between autophagy and senescence was further examined through pharmacologic inhibition of autophagy with chloroquine and 3-methyl-adenine and genetic ablation of the autophagy-related genes ATG5 and ATG7. However, inhibition of autophagy by pharmacological and genetic approaches could not entirely abrogate the senescence response, which was only reduced and/or delayed. Taken together, our findings suggest that autophagy and senescence tend to occur in parallel, and furthermore that autophagy accelerates the development of the senescent phenotype. However, these responses are not inexorably linked or interdependent, as senescence can occur when autophagy is abrogated.
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Affiliation(s)
- Rachel W Goehe
- Departments of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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22
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Wang J, Teves ME, Shen X, Nagarkatti-Gude DR, Hess RA, Henderson SC, Strauss JF, Zhang Z. Mouse RC/BTB2, a member of the RCC1 superfamily, localizes to spermatid acrosomal vesicles. PLoS One 2012; 7:e39846. [PMID: 22768142 PMCID: PMC3387240 DOI: 10.1371/journal.pone.0039846] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/31/2012] [Indexed: 12/01/2022] Open
Abstract
Mouse RC/BTB2 is an unstudied protein of the RCC1 (Regulator of Chromosome Condensation) superfamily. Because of the significant remodeling of chromatin that occurs during spermiogenesis, we characterized the expression and localization of mouse RC/BTB2 in the testis and male germ cells. The Rc/btb2 gene yields two major transcripts: 2.3 kb Rc/btb2-s, present in most somatic tissues examined; and 2.5 kb Rc/btb2-t, which contains a unique non-translated exon in its 5'-UTR that is only detected in the testis. During the first wave of spermatogenesis, Rc/btb2-t mRNA is expressed from day 8 after birth, reaching highest levels of expression at day 30 after birth. The full-length protein contains three RCC1 domains in the N-terminus, and a BTB domain in the C-terminus. In the testis, the protein is detectable from day 12, but is progressively up-regulated to day 30 and day 42 after birth. In spermatids, some of the protein co-localizes with acrosomal markers sp56 and peanut lectin, indicating that it is an acrosomal protein. A GFP-tagged RCC1 domain is present throughout the cytoplasm of transfected CHO cells. However, both GFP-tagged, full-length RC/BTB2 and a GFP-tagged BTB domain localize to vesicles in close proximity to the nuclear membrane, suggesting that the BTB domain might play a role in mediating full-length RC/BTB2 localization. Since RCC1 domains associate with Ran, a small GTPase that regulates molecular trafficking, it is possible that RC/BTB2 plays a role in transporting proteins during acrosome formation.
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Affiliation(s)
- Jiannan Wang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Maria E. Teves
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Xuening Shen
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - David R. Nagarkatti-Gude
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Rex A. Hess
- Department of Comparative Biosciences, College of Veterinary Medicine, University of Illinois, Urbana, Illinois, United States of America
| | - Scott C. Henderson
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jerome F. Strauss
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Zhibing Zhang
- Department of Obstetrics & Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Biochemistry & Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
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23
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Bristol ML, Di X, Beckman MJ, Wilson EN, Henderson SC, Maiti A, Fan Z, Gewirtz DA. Dual functions of autophagy in the response of breast tumor cells to radiation: cytoprotective autophagy with radiation alone and cytotoxic autophagy in radiosensitization by vitamin D 3. Autophagy 2012; 8:739-53. [PMID: 22498493 DOI: 10.4161/auto.19313] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In MCF-7 breast tumor cells, ionizing radiation promoted autophagy that was cytoprotective; pharmacological or genetic interference with autophagy induced by radiation resulted in growth suppression and/or cell killing (primarily by apoptosis). The hormonally active form of vitamin D, 1,25D 3, also promoted autophagy in irradiated MCF-7 cells, sensitized the cells to radiation and suppressed the proliferative recovery that occurs after radiation alone. 1,25D 3 enhanced radiosensitivity and promoted autophagy in MCF-7 cells that overexpress Her-2/neu as well as in p53 mutant Hs578t breast tumor cells. In contrast, 1,25D 3 failed to alter radiosensitivity or promote autophagy in the BT474 breast tumor cell line with low-level expression of the vitamin D receptor. Enhancement of MCF-7 cell sensitivity to radiation by 1,25D 3 was not attenuated by a genetic block to autophagy due largely to the promotion of apoptosis via the collateral suppression of protective autophagy. However, MCF-7 cells were protected from the combination of 1,25D 3 with radiation using a concentration of chloroquine that produced minimal sensitization to radiation alone. The current studies are consistent with the premise that while autophagy mediates a cytoprotective function in irradiated breast tumor cells, promotion of autophagy can also confer radiosensitivity by vitamin D (1,25D 3). As both cytoprotective and cytotoxic autophagy can apparently be expressed in the same experimental system in response to radiation, this type of model could be utilized to distinguish biochemical, molecular and/or functional differences in these dual functions of autophagy.
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Affiliation(s)
- Molly L Bristol
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
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24
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25
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Shepherd MN, Pomicter AD, Velazco CS, Henderson SC, Dupree JL. Paranodal reorganization results in the depletion of transverse bands in the aged central nervous system. Neurobiol Aging 2012; 33:203.e13-24. [PMID: 20888080 PMCID: PMC3282488 DOI: 10.1016/j.neurobiolaging.2010.08.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 07/26/2010] [Accepted: 08/05/2010] [Indexed: 11/16/2022]
Abstract
Paranodal axo-glial junctional complexes anchor the myelin sheath to the axon and breakdown of these complexes presumably facilitates demyelination. Myelin deterioration is also prominent in the aging central nervous system (CNS); however, the stability of the paranodal complexes in the aged CNS has not been examined. Here, we show that transverse bands, prominent components of paranodal junctions, are significantly reduced in the aged CNS; however, the number of paired clusters of both myelin and axonal paranodal proteins is not altered. Ultrastructural analyses also reveal that thicker myelin sheaths display a "piling" of paranodal loops, the cytoplasm-containing sacs that demarcate the paranode. Loops involved in piling are observed throughout the paranode and are not limited to loops positioned in either the nodal- or juxtanodal-most regions. Here, we propose that as myelination continues, previously anchored loops lose their transverse bands and recede away from the axolemma. Newly juxtaposed loops then lose their transverse bands, move laterally to fill in the gap left by the receded loops and finally reform their transverse bands. This paranodal reorganization results in conservation of paranodal length, which may be important in maintaining ion channel spacing and axonal function. Furthermore, we propose that transverse band reformation is less efficient in the aged CNS, resulting in the significant reduction of these junctional components. Although demyelination was not observed, we propose that loss of transverse bands facilitates myelin degeneration and may predispose the aged CNS to a poorer prognosis following a secondary insult.
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Affiliation(s)
- Mark N. Shepherd
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
- MD Biosciences, 2575 University Avenue W. Suite 100 St Paul, MN, USA 55114 (present address)
| | - Anthony D. Pomicter
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Cristine S. Velazco
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Scott C. Henderson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
| | - Jeffrey L. Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA, USA 23298
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Nagarkatti-Gude DR, Jaimez R, Henderson SC, Teves ME, Zhang Z, Strauss JF. Spag16, an axonemal central apparatus gene, encodes a male germ cell nuclear speckle protein that regulates SPAG16 mRNA expression. PLoS One 2011; 6:e20625. [PMID: 21655194 PMCID: PMC3105110 DOI: 10.1371/journal.pone.0020625] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Accepted: 05/05/2011] [Indexed: 11/28/2022] Open
Abstract
Spag16 is the murine orthologue of Chlamydomonas reinhardtii PF20, a protein known to be essential to the structure and function of the "9+2" axoneme. In Chlamydomonas, the PF20 gene encodes a single protein present in the central pair of the axoneme. Loss of PF20 prevents central pair assembly/integrity and results in flagellar paralysis. Here we demonstrate that the murine Spag16 gene encodes two proteins: 71 kDa SPAG16L, which is found in all murine cells with motile cilia or flagella, and 35 kDa SPAG16S, representing the C terminus of SPAG16L, which is expressed only in male germ cells, and is predominantly found in specific regions within the nucleus that also contain SC35, a known marker of nuclear speckles enriched in pre-mRNA splicing factors. SPAG16S expression precedes expression of SPAG16L. Mice homozygous for a knockout of SPAG16L alone are infertile, but show no abnormalities in spermatogenesis. Mice chimeric for a mutation deleting the transcripts for both SPAG16L and SPAG16S have a profound defect in spermatogenesis. We show here that transduction of SPAG16S into cultured dispersed mouse male germ cells and BEAS-2B human bronchial epithelial cells increases SPAG16L expression, but has no effect on the expression of several other axoneme components. We also demonstrate that the Spag16L promoter shows increased activity in the presence of SPAG16S. The distinct nuclear localization of SPAG16S and its ability to modulate Spag16L mRNA expression suggest that SPAG16S plays an important role in the gene expression machinery of male germ cells. This is a unique example of a highly conserved axonemal protein gene that encodes two protein products with different functions.
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Affiliation(s)
- David R. Nagarkatti-Gude
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Ruth Jaimez
- Center for Research on Reproduction and Women's Health, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Scott C. Henderson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Maria E. Teves
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Zhibing Zhang
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
| | - Jerome F. Strauss
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, Richmond, Virginia, United States of America
- Department of Obstetrics and Gynecology, Virginia Commonwealth University, Richmond, Virginia, United States of America
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27
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Fillmore HL, Shultz MD, Henderson SC, Cooper P, Broaddus WC, Chen ZJ, Shu CY, Zhang J, Ge J, Dorn HC, Corwin F, Hirsch JI, Wilson J, Fatouros PP. Conjugation of functionalized gadolinium metallofullerenes with IL-13 peptides for targeting and imaging glial tumors. Nanomedicine (Lond) 2011; 6:449-58. [PMID: 21542684 DOI: 10.2217/nnm.10.134] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: Glioblastoma multiforme is the most common and most lethal primary brain tumor in humans, with median survival of approximately 1 year. Owing to the ability of glioma cells to aggressively infiltrate normal brain tissue and survive exposure to current adjuvant therapies, there is a great need for specific targeted nanoplatforms capable of delivering both therapeutic and imaging agents directly to invasive tumor cells. Method: Gadolinium-containing endohedral fullerenes, highly efficient contrast agents for MRI, were functionalized and conjugated with a tumor-specific peptide and assessed for their ability to bind to glioma cells in vitro. Results: We report the successful conjugation of the carboxyl functionalized metallofullerene Gd3N@C80(OH)-26(CH2CH2COOH)-16 to IL-13 peptides and the successful targeting ability towards brain tumor cells that overexpress the IL-13 receptor (IL-13Rα2). Conclusion: These studies demonstrate that IL-13 peptide-conjugated gadolinium metallofullerenes could serve as a platform to deliver imaging and therapeutic agents to tumor cells.
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Affiliation(s)
| | | | - Scott C Henderson
- Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Patricia Cooper
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA; 4111 Monarch Way, Suite 203, Office of Research, Old Dominion University, Norfolk, VA 23508, USA
| | - William C Broaddus
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA; 4111 Monarch Way, Suite 203, Office of Research, Old Dominion University, Norfolk, VA 23508, USA
| | - Zhi Jian Chen
- Department of Neurosurgery, Virginia Commonwealth University, Richmond, VA, USA; 4111 Monarch Way, Suite 203, Office of Research, Old Dominion University, Norfolk, VA 23508, USA
| | - Chun-Ying Shu
- Department of Chemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA, USA
| | - Jianfei Zhang
- Department of Chemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA, USA
| | - Jiechao Ge
- Department of Chemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA, USA
| | - Harry C Dorn
- Department of Chemistry, Virginia Polytechnic Institute & State University, Blacksburg, VA, USA
| | - Frank Corwin
- Radiology, Virginia Commonwealth University, Richmond, VA, USA
| | - Jerry I Hirsch
- Radiology, Virginia Commonwealth University, Richmond, VA, USA
| | - John Wilson
- Radiology, Virginia Commonwealth University, Richmond, VA, USA
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Zhang J, Ge J, Shultz MD, Chung E, Singh G, Shu C, Deck PA, Fatouros PP, Henderson SC, Corwin FD, Geohegan DB, Puretzky AA, Rouleau CM, More K, Rylander C, Rylander MN, Gibson HW, Dorn HC. In vitro and in vivo studies of single-walled carbon nanohorns with encapsulated metallofullerenes and exohedrally functionalized quantum dots. Nano Lett 2010; 10:2843-8. [PMID: 20698597 PMCID: PMC2935139 DOI: 10.1021/nl1008635] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Single-walled carbon nanohorns (SWNHs) are new carbonaceous materials. In this paper, we report the first successful preparation of SWNHs encapsulating trimetallic nitride template endohedral metallofullerenes (TNT-EMFs). The resultant materials were functionalized by a high-speed vibration milling method and conjugated with CdSe/ZnS quantum dots (QDs). The successful encapsulation of TNT-EMFs and external functionalization with QDs provide a dual diagnostic platform for in vitro and in vivo biomedical applications of these new carbonaceous materials.
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Affiliation(s)
- Jianfei Zhang
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Jiechao Ge
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Michael D. Shultz
- Department of Radiology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Eunna Chung
- Department of Mechanical Engineering and School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Gurpreet Singh
- Institute for Critical Technology and Applied Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Chunying Shu
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Paul A. Deck
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Panos P. Fatouros
- Department of Radiology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Scott C. Henderson
- Department of Anatomy & Neurobiology, Virginia Commonwealth University, Richmond, VA, 23298
| | - Frank D. Corwin
- Department of Radiology, Virginia Commonwealth University, Richmond, VA, 23298
| | - David B. Geohegan
- Center for Nanophase Materials Sciences and SHARE Facilities, Oak Ridge National Laboratories, Oak Ridge, TN, 37831
| | - Alex A. Puretzky
- Center for Nanophase Materials Sciences and SHARE Facilities, Oak Ridge National Laboratories, Oak Ridge, TN, 37831
| | - Christopher M. Rouleau
- Center for Nanophase Materials Sciences and SHARE Facilities, Oak Ridge National Laboratories, Oak Ridge, TN, 37831
| | - Karren More
- Center for Nanophase Materials Sciences and SHARE Facilities, Oak Ridge National Laboratories, Oak Ridge, TN, 37831
| | - Christopher Rylander
- Department of Mechanical Engineering and School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Marissa Nichole Rylander
- Department of Mechanical Engineering and School of Biomedical Engineering and Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Harry W. Gibson
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
| | - Harry C. Dorn
- Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060
- Correspondence author: Harry C. Dorn, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA, 24060; ; Phone: 540-231-5953; Fax: 540-231-3255
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Abstract
OBJECTIVE Estimate the proportion of phosphodiesterase type-5 inhibitor (PDE5-I) patients who co-possess nitrates and compare the proportion of tadalafil patients dispensed nitrates to a matched control group. Secondarily, examine the percentage of co-possession of PDE5-Is and nitrates where the products were dispensed on the same day or written by the same prescriber. METHODS Male patients aged 18+ years filling PDE5-I prescriptions between December 2003 and March 2006 were identified using a U.S. longitudinal prescription database (IMS Health LRx). Similar patients not dispensed a PDE5-I during this period were matched to the tadalafil-dispensed cohort using a propensity score approach. Co-possession, as a proxy for concurrent use, was defined as an overlap in time on therapy for a PDE5-I and nitrate and was compared for the three PDE5-Is and for tadalafil to the matched control group. RESULTS Among 601,063 tadalafil patients, 3.31% were dispensed a nitrate during the study period, compared to 6.18% in control patients (n = 601,063). When co-possessed prescriptions were defined by overlapping exposure periods, the proportion of PDE5-I patients with co-possessed nitrates ranged from 1.44% (tadalafil) to 1.72% (vardenafil) and 2.13% (sildenafil). Co-possession percentages of PDE5-I prescriptions were 0.83% for tadalafil and 1.07% for sildenafil and vardenafil. The majority (54.29%) of co-possessed PDE5-I and nitrate prescriptions had the nitrate dispensed prior to the PDE5-I prescription identified in the study cohort. CONCLUSIONS Keeping in mind the limitations of observational studies, these results suggest that co-dispensing of nitrates and PDE5-Is is low. Compared to control patients, the proportion of nitrate co-possession was lowest for patients filling tadalafil. Tadalafil patients also had the lowest co-possessed proportion among the three PDE5-I cohorts. While the majority of co-possessed drug pairs were prescribed by different providers, the highest percentage of co-prescribing from the same physician was among cardiologists. These results suggest that physicians adhere to contraindications and are careful about co-prescribing of nitrates with PDE-5Is.
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Di X, Henderson SC, Gewirtz DA. Abstract 3221: Analysis of the relationship between autophagy and senescence in response to Adriamycin in breast tumor cells. Cancer Res 2010. [DOI: 10.1158/1538-7445.am10-3221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Autophagy is a conservative biological process, which involves the degradation of intracellular components (proteins or organelles) via the fusion of autophagosomes with lysosomes. Autophagy has been reported to have both cytoprotective and cytotoxic actions in response to either chemotherapy or radiation in different tumor model systems. In previous studies (Elmore LW et al., J Biol Chem. 2002 Sep 20; 277(38): 35509-15.), Adriamycin (doxorubicin), one of the primary chemotherapeutic drugs utilized in the treatment of breast cancer, was shown to induce a pronounced senescence response within 72hrs in MCF-7 breast tumor cells (at a clinically relevant concentration of 1μM, with a 2 hr exposure). Interestingly, Adriamycin was also observed to cause a time-dependent increase of autophagy within 72hrs (by acridine orange, Monodansylcadaverine) staining and electron microscopy). The current study was designed to evaluate the relationship between Adriamycin-induced autophagy and senescence in MCF-7 breast tumor cells. The antioxidants, GSH (glutathione) and NAC (N-acetyl cysteine), were previously shown to effectively block Adriamycin-induced senescence (Di X. et al., Biochem Pharmacol. 2009 Apr 1; 77(7):1139-50.). We now demonstrate that both GSH and NAC also effectively abolish Adriamycin-induced autophagy in MCF-7cells (as confirmed by the disappearance of punctuated red fluorescence staining (RFP-LC3) induced by Adriamycin. Unexpectedly, however, the autophagy inhibitors, 3-MA or wortmannin, failed to block Adriamycin-induced senescence (based on β-Gal staining). Another autophagy inhibitor, chloroquine, showed a significant blockade to β-Gal staining, although typical senescence morphology phenotypes, such as cell enlargement and flattening were still observed by phase contrast microscopy. Silencing of the autophagic protein, ATG5, failed to completely block Adriamycin-induced senescence, although the MCF-7/ATG5 knockdown cells showed decreased and delayed β-Gal staining. Taken together, our studies suggest that that autophagy proceeds and may contribute to the development of Adriamycin-induced senescence. The fact that blockade of senescence (by reactive oxygen scavengers) abrogates Adriamycin-induced autophagy further suggests that senescence and autophagy may be collaterally regulated in response to Adriamycin in MCF-7 cells. Both autophagy and senescence may be related to tumor dormancy (Gewirtz DA, Autophagy. 2009 Nov 24; 5(8).). Further studies are in progress to delineate the roles (cytoprotective or cytotoxic) of autophagy and the relationship of autophagy to senescence, tumor dormancy and sensitivity to chemotherapy and radiation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3221.
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Affiliation(s)
- Xu Di
- 1VCU Massey Cancer Ctr., Richmond, VA
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Seegar TCM, Eller B, Tzvetkova-Robev D, Kolev MV, Henderson SC, Nikolov DB, Barton WA. Tie1-Tie2 interactions mediate functional differences between angiopoietin ligands. Mol Cell 2010; 37:643-55. [PMID: 20227369 DOI: 10.1016/j.molcel.2010.02.007] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2009] [Revised: 09/18/2009] [Accepted: 12/21/2009] [Indexed: 11/17/2022]
Abstract
The Tie family of endothelial-specific receptor tyrosine kinases is essential for cell proliferation, migration, and survival during angiogenesis. Despite considerable similarity, experiments with Tie1- or Tie2-deficient mice highlight distinct functions for these receptors in vivo. The Tie2 receptor is further unique with respect to its structurally homologous ligands. Angiopoietin-2 and -3 can function as agonists or antagonists; angiopoietin-1 and -4 are constitutive agonists. To address the role of Tie1 in angiopoietin-mediated Tie2 signaling and determine the basis for the behavior of the individual angiopoietins, we used an in vivo FRET-based proximity assay to monitor Tie1 and -2 localization and association. We provide evidence for Tie1-Tie2 complex formation on the cell surface and identify molecular surface areas essential for receptor-receptor recognition. We further demonstrate that the Tie1-Tie2 interactions are dynamic, inhibitory, and differentially modulated by angiopoietin-1 and -2. Based on the available data, we propose a unified model for angiopoietin-induced Tie2 signaling.
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Affiliation(s)
- Tom C M Seegar
- Department of Biochemistry and Molecular Biology, Virginia Commonwealth University, 1101 East Marshall Street, Richmond, VA 23298, USA
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32
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Shroff SM, Pomicter AD, Chow WN, Fox MA, Colello RJ, Henderson SC, Dupree JL. Adult CST-null mice maintain an increased number of oligodendrocytes. J Neurosci Res 2010; 87:3403-14. [PMID: 19224580 DOI: 10.1002/jnr.22003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The galactolipids galactocerebroside and sulfatide have been implicated in oligodendrocyte (OL) development and myelin formation. Much of the early evidence for myelin galactolipid function has been derived from antibody and chemical perturbation of OLs in vitro. To determine the role of these lipids in vivo, we previously characterized mice lacking galactocerebroside and sulfatide and observed abundant, unstable myelin and an increased number of OLs. We have also reported that mice incapable of synthesizing sulfatide (CST-null) while maintaining normal levels of galactocerebroside generate relatively stable myelin with unstable paranodes. Additionally, Hirahara et al. (2004; Glia 45:269-277) reported that these CST-null mice also contain an increased number of OLs in the forebrain, medulla, and cerebellum at 7 days of age. Here, we further the findings of Hirahara et al. by demonstrating that the number of OLs in the CST-null mice is also increased in the spinal cord and that this elevated OL population is maintained through, at least, 7 months of age. Moreover, we show that the enhanced OL population is accompanied by increased proliferation and decreased apoptosis of oligodendrocytic-lineage cells. Finally, through ultrastructural analysis, we show that the CST-null OLs exhibit decreased morphological complexity, a feature that may result in decreased OL competition and increased OL survival.
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Affiliation(s)
- S M Shroff
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia, USA
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Bogaard HJ, Natarajan R, Henderson SC, Long CS, Kraskauskas D, Smithson L, Ockaili R, McCord JM, Voelkel NF. Chronic Pulmonary Artery Pressure Elevation Is Insufficient to Explain Right Heart Failure. Circulation 2009; 120:1951-60. [DOI: 10.1161/circulationaha.109.883843] [Citation(s) in RCA: 402] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
The most important determinant of longevity in pulmonary arterial hypertension is right ventricular (RV) function, but in contrast to experimental work elucidating the pathobiology of left ventricular failure, there is a paucity of data on the cellular and molecular mechanisms of RV failure.
Methods and Results—
A mechanical animal model of chronic progressive RV pressure overload (pulmonary artery banding, not associated with structural alterations of the lung circulation) was compared with an established model of angioproliferative pulmonary hypertension associated with fatal RV failure. Isolated RV pressure overload induced RV hypertrophy without failure, whereas in the context of angioproliferative pulmonary hypertension, RV failure developed that was associated with myocardial apoptosis, fibrosis, a decreased RV capillary density, and a decreased vascular endothelial growth factor mRNA and protein expression despite increased nuclear stabilization of hypoxia-induced factor-1α. Induction of myocardial nuclear factor E2-related factor 2 and heme-oxygenase 1 with a dietary supplement (Protandim) prevented fibrosis and capillary loss and preserved RV function despite continuing pressure overload.
Conclusion—
These data brought into question the commonly held concept that RV failure associated with pulmonary hypertension is due strictly to the increased RV afterload.
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Affiliation(s)
- Harm J. Bogaard
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Ramesh Natarajan
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Scott C. Henderson
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Carlin S. Long
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Donatas Kraskauskas
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Lisa Smithson
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Ramzi Ockaili
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Joe M. McCord
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
| | - Norbert F. Voelkel
- From the Divisions of Pulmonary and Critical Care (H.J.B., R.N., D.K., L.S., N.F.V.) and Cardiology (R.O.), Department of Medicine, and Department of Anatomy and Neurobiology (S.C.H.), Virginia Commonwealth University, Richmond; Department of Pulmonary Medicine, VU University Medical Center, Amsterdam, the Netherlands (H.J.B.); and Divisions of Cardiology (C.S.L.) and Pulmonary Sciences (J.M.M.), Department of Medicine, University of Colorado at Denver and Health Sciences Center, Aurora
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Collins C, Klausner AP, Herrick B, Koo HP, Miner AS, Henderson SC, Ratz PH. Potential for control of detrusor smooth muscle spontaneous rhythmic contraction by cyclooxygenase products released by interstitial cells of Cajal. J Cell Mol Med 2009; 13:3236-50. [PMID: 19243470 PMCID: PMC4516481 DOI: 10.1111/j.1582-4934.2009.00714.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Interstitial cells of Cajal (ICCs) have been identified as pacemaker cells in the upper urinary tract and urethra, but the role of ICCs in the bladder remains to be determined. We tested the hypotheses that ICCs express cyclooxygenase (COX), and that COX products (prostaglandins), are the cause of spontaneous rhythmic contraction (SRC) of isolated strips of rabbit bladder free of urothelium. SRC was abolished by 10 μM indomethacin and ibuprofen (non-selective COX inhibitors). SRC was concentration-dependently inhibited by selective COX-1 (SC-560 and FR-122047) and COX-2 inhibitors (NS-398 and LM-1685), and by SC-51089, a selective antagonist for the PGE-2 receptor (EP) and ICI-192,605 and SQ-29,548, selective antagonists for thromboxane receptors (TP). The partial agonist/antagonist of the PGF-2α receptor (FP), AL-8810, inhibited SRC by ∼50%. Maximum inhibition was ∼90% by SC-51089, ∼80–85% by the COX inhibitors and ∼70% by TP receptor antagonists. In the presence of ibuprofen to abolish SRC, PGE-2, sulprostone, misoprostol, PGF-2α and U-46619 (thromboxane mimetic) caused rhythmic contractions that mimicked SRC. Fluorescence immunohistochemistry coupled with confocal laser scanning microscopy revealed that c-Kit and vimentin co-localized to interstitial cells surrounding detrusor smooth muscle bundles, indicating the presence of extensive ICCs in rabbit bladder. Co-localization of COX-1 and vimentin, and COX-2 and vimentin by ICCs supports the hypothesis that ICCs were the predominant cell type in rabbit bladder expressing both COX isoforms. These data together suggest that ICCs appear to be an important source of prostaglandins that likely play a role in regulation of SRC. Additional studies on prostaglandin-dependent SRC may generate opportunities for the application of novel treatments for disorders leading to overactive bladder.
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Affiliation(s)
- Clinton Collins
- Department of Surgery, Urology Division, Virginia Commonwealth University School of Medicine, VA 23298-0614, USA
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35
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Hanss B, Leal-Pinto E, Teixeira A, Tran B, Lee CH, Henderson SC, Klotman PE. Localization of the Nucleic Acid Channel Regulatory Subunit, Cytosolic Malate Dehydrogenase. J Membr Biol 2008; 226:1-8. [DOI: 10.1007/s00232-008-9133-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2008] [Accepted: 09/29/2008] [Indexed: 10/21/2022]
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36
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Ayres CE, Jha BS, Meredith H, Bowman JR, Bowlin GL, Henderson SC, Simpson DG. Measuring fiber alignment in electrospun scaffolds: a user's guide to the 2D fast Fourier transform approach. J Biomater Sci Polym Ed 2008; 19:603-21. [PMID: 18419940 DOI: 10.1163/156856208784089643] [Citation(s) in RCA: 206] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this study we describe how to use a two-dimensional fast Fourier transform (2D FFT) approach to measure fiber alignment in electrospun materials. This image processing function can be coupled with a variety of imaging modalities to assign an objective numerical value to scaffold anisotropy. A data image of an electrospun scaffold is composed of pixels that depict the spatial organization of the constituent fibers. The 2D FFT function converts this spatial information into a mathematically defined frequency domain that maps the rate at which pixel intensities change across the original data image. This output image also contains quantitative information concerning the orientation of objects in a data image. We discuss the theory and practice of using the frequency plot of the 2D FFT function to measure relative scaffold anisotropy and identify the principal axis of fiber orientation. We note that specific degrees of scaffold anisotropy may represent a critical design feature in the fabrication of tissues that will be subjected to well-defined uniaxial mechanical loads. This structural property may also represent a source of guidance cues that can be exploited to regulate cell phenotype.
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Affiliation(s)
- Chantal E Ayres
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23116, USA
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37
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Schanuel SM, Bell KA, Henderson SC, McQuiston AR. Heterologous expression of the invertebrate FMRFamide-gated sodium channel as a mechanism to selectively activate mammalian neurons. Neuroscience 2008; 155:374-86. [PMID: 18598740 DOI: 10.1016/j.neuroscience.2008.05.052] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 05/30/2008] [Accepted: 05/30/2008] [Indexed: 01/01/2023]
Abstract
Considerable effort has been directed toward the development of methods to selectively activate specific subtypes of neurons. Focus has been placed on the heterologous expression of proteins that are capable of exciting neurons in which they are expressed. Here we describe the heterologous expression of the invertebrate FMRFamide (H-phenylalanine-methionine-arginine-phenylalanine-NH2) -gated sodium channel from Helix aspersa (HaFaNaC) in hippocampal slice cultures. HaFaNaC was co-expressed with a fluorescent protein (green fluorescent protein (GFP), red fluorescent protein from Discosoma sp (dsRed) or mutated form of red fluorescent protein from Discosoma sp (tdTomato)) in CA3 pyramidal neurons of rat hippocampal slice cultures using single cell electroporation. Pressure application of the agonist FMRFamide to HaFaNaC-expressing neuronal somata produced large prolonged depolarizations and bursts of action potentials (APs). FMRFamide responses were inhibited by amiloride (100 microM). In contrast, pressure application of FMRFamide to the axons of neurons expressing HaFaNaC produced no response. Fusion of GFP to the N-terminus of HaFaNaC showed that GFP-HaFaNaC was absent from axons. Bath application of FMRFamide produced persistent AP firing in HaFaNaC-expressing neurons. This FMRFamide-induced increase in the frequency of APs was dose-dependent. The concentrations of FMRFamide required to activate HaFaNaC-expressing neurons were below that required to activate the homologous acid sensing ion channel normally found in mammalian neurons. Furthermore, the mammalian neuropeptides neuropeptide FF and RFamide-related peptide-1, which have amidated RF C-termini, did not affect HaFaNaC-expressing neurons. Antagonists of NPFF receptors (BIBP3226) also had no effect on HaFaNaC. Therefore, we suggest that heterologous-expression of HaFaNaC in mammalian neurons could be a useful method to selectively and persistently excite specific subtypes of neurons in intact nervous tissue.
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Affiliation(s)
- S M Schanuel
- Department of Anatomy and Neurobiology, Virginia Commonwealth University School of Medicine, Box 980709, Richmond, VA 23298, USA
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38
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Kurz JE, Moore BJ, Henderson SC, Campbell JN, Churn SB. A cellular mechanism for dendritic spine loss in the pilocarpine model of status epilepticus. Epilepsia 2008; 49:1696-710. [PMID: 18479390 DOI: 10.1111/j.1528-1167.2008.01616.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE Previous studies have documented a synaptic translocation of calcineurin (CaN) and increased CaN activity following status epilepticus (SE); however, the cellular effect of these changes in CaN in the pathology of SE remains to be elucidated. This study examined a CaN-dependent modification of the dendritic cytoskeleton. CaN has been shown to induce dephosphorylation of cofilin, an actin depolymerization factor. The ensuing actin depolymerization can lead to a number of physiological changes that are of interest in SE. METHODS SE was induced by pilocarpine injection, and seizure activity was monitored by video-EEG. Subcellular fractions were isolated by differential centrifugation. CaN activity was assayed using a paranitrophenol phosphate (pNPP) assay protocol. Cofilin phosphorylation was assessed using phosphocofilin-specific antibodies. Cofilin-actin binding was determined by coimmunoprecipitation, and actin polymerization was measured using a triton-solubilization protocol. Spines were visualized using a single-section rapid Golgi impregnation procedure. RESULTS The immunoreactivity of phosphocofilin decreased significantly in hippocampal and cortical synaptosomal samples after SE. SE-induced cofilin dephosphorylation could be partially blocked by the preinjection of CaN inhibitors. Cofilin activation could be further demonstrated by increased actin-cofilin binding and a significant depolymerization of neuronal actin, both of which were also blocked by CaN inhibitors. Finally, we demonstrated a CaN-dependent loss of dendritic spines histologically. DISCUSSION The data demonstrate a CaN-dependent, cellular mechanism through which prolonged seizure activity results in loss of dendritic spines via cofilin activation. Further research into this area may provide useful insights into the pathology of SE and epileptogenic mechanisms.
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Affiliation(s)
- Jonathan E Kurz
- Department of Neurology, Virginia Commonwealth University, Richmond, Virginia 23298, USA
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39
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Maples KM, Henderson SC, Graham M, Irani AM. Treatment of eosinophilic esophagitis with inhaled budesonide in a 7-year-old boy with concomitant persistent asthma: resolution of esophageal submucosal fibrosis and eosinophilic infiltration. Ann Allergy Asthma Immunol 2008; 99:572-4. [PMID: 18219842 DOI: 10.1016/s1081-1206(10)60390-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
OBJECTIVE Determine whether monthly dosing of bisphosphonates has an impact on persistence relative to weekly dosing. METHODS We used the IMS Longitudinal Prescription database of retail prescription records to study 165,955 women aged 50 years or older newly initiated on therapy between September and November 2005 with no bisphosphonate prescriptions in the prior 12 months. All patients were followed for 365 days from their initial prescription and were considered persistent until they had a refill gap greater than 30 days between the end of the day's supply of one prescription and the beginning of the next. Proportional-hazards regression models were executed to compare persistence across bisphosphonates. Persistence may be underestimated because of the following: (1) we had no information on the receipt of samples; (2) we had no information about refills at pharmacies that did not participate in the IMS prescription database, (3) switched patients were excluded; and (4) the cohort was limited to patients newly initiated on bisphosphonates. RESULTS Patients initiating on monthly ibandronate had a lower average persistence duration (98 days) than weekly alendronate (116 days) and risedronate (113 days) patients (p < 0.0001). Based on the proportional-hazards model, monthly ibandronate patients were 10% more likely to discontinue than alendronate patients (HR = 1.10, p < 0.0001). After removing the patients who failed to refill after their initial prescription, persistence beyond patients' first refill were similar across the three bisphosphonates. CONCLUSIONS Monthly dosing does not appear to be associated with improvements in patient persistence with oral bisphosphonates for patients newly initiated on bisphosphonates.
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Affiliation(s)
- Thomas W Weiss
- US Outcomes Research, Merck & Co., Inc., West Point, PA 19486-0004, USA.
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41
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Tozer JT, Henderson SC, Sun D, Colello RJ. Photoconversion using confocal laser scanning microscopy: A new tool for the ultrastructural analysis of fluorescently labeled cellular elements. J Neurosci Methods 2007; 164:240-6. [PMID: 17586051 PMCID: PMC3282580 DOI: 10.1016/j.jneumeth.2007.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2007] [Revised: 04/30/2007] [Accepted: 05/01/2007] [Indexed: 11/15/2022]
Abstract
Photoconversion, the method by which a fluorescent dye is transformed into a stable, osmiophilic product that can be visualized by transmission electron microscopy, is the most widely used method to enable the ultrastructural analysis of fluorescently labeled cellular structures. Nevertheless, the conventional method of photoconversion using widefield fluorescence microscopy requires long reaction times and results in low resolution cell targeting which limit its utility. Accordingly, we developed a photoconversion method that ameliorates these limitations by adapting confocal laser scanning microscopy to the procedure. We confirmed that photoconversion times were dramatically reduced when using a confocal laser scanning microscope in the photoconversion process. We also demonstrated that the region of interest scanning capabilities of a confocal laser scanning microscope equipped with an acousto-optical tunable filter represented a unique tool to facilitate the targeting of the photoconversion process to individual cellular or subcellular elements within a fluorescent field. Moreover, region of interest scanning greatly reduced the area of the cell exposed to light energy, ameliorating the ultrastructural damage common to this process when widefield microscopes are employed. The potential of this new methodology extends beyond the neurosciences to any scientific modality which requires ultrastructural analysis of fluorescently labeled specimens, especially those where discrete photoconversion on a cellular or subcellular basis could be beneficial.
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Affiliation(s)
- Jordan T. Tozer
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, VA, 23298
| | - Scott C. Henderson
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, VA, 23298
| | - Dong Sun
- Department of Neurosurgery, School of Medicine, Virginia Commonwealth University, Richmond, VA, 23298
| | - Raymond J. Colello
- Department of Anatomy and Neurobiology, School of Medicine, Virginia Commonwealth University, Richmond, VA, 23298
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42
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Ayres C, Bowlin GL, Henderson SC, Taylor L, Shultz J, Alexander J, Telemeco TA, Simpson DG. Modulation of anisotropy in electrospun tissue-engineering scaffolds: Analysis of fiber alignment by the fast Fourier transform. Biomaterials 2006; 27:5524-34. [PMID: 16859744 PMCID: PMC2929953 DOI: 10.1016/j.biomaterials.2006.06.014] [Citation(s) in RCA: 193] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2006] [Accepted: 06/20/2006] [Indexed: 11/16/2022]
Abstract
We describe the use of the fast Fourier transform (FFT) in the measurement of anisotropy in electrospun scaffolds of gelatin as a function of the starting conditions. In electrospinning, fiber alignment and overall scaffold anisotropy can be manipulated by controlling the motion of the collecting mandrel with respect to the source electrospinning solution. By using FFT to assign relative alignment values to an electrospun matrix it is possible to systematically evaluate how different processing variables impact the structure and material properties of a scaffold. Gelatin was suspended at varying concentrations (80, 100, 130, 150 mg/ml) and electrospun from 2,2,2 trifluoroethanol onto rotating mandrels (200-7000 RPM). At each starting concentration, fiber diameter remained constant over a wide range of mandrel RPM. Scaffold anisotropy developed as a function of fiber diameter and mandrel RPM. The induction of varying degrees of anisotropy imparted distinctive material properties to the electrospun scaffolds. The FFT is a rapid method for evaluating fiber alignment in tissue-engineering materials.
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Affiliation(s)
- Chantal Ayres
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23298, USA
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43
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Wearne SL, Rodriguez A, Ehlenberger DB, Rocher AB, Henderson SC, Hof PR. New techniques for imaging, digitization and analysis of three-dimensional neural morphology on multiple scales. Neuroscience 2006; 136:661-80. [PMID: 16344143 DOI: 10.1016/j.neuroscience.2005.05.053] [Citation(s) in RCA: 240] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 05/17/2005] [Accepted: 05/19/2005] [Indexed: 01/15/2023]
Abstract
Cognitive impairment in normal aging and neurodegenerative diseases is accompanied by altered morphologies on multiple scales. Understanding of the role of these structural changes in producing functional deficits in brain aging and neuropsychiatric disorders requires accurate three-dimensional representations of neuronal morphology, and realistic biophysical modeling that can directly relate structural changes to altered neuronal firing patterns. To date however, tools capable of resolving, digitizing and analyzing neuronal morphology on both local and global scales, and with sufficient throughput and automation, have been lacking. The precision of existing image analysis-based morphometric tools is restricted at the finest scales, where resolution of fine dendritic features and spine geometry is limited by the skeletonization methods used, and by quantization errors arising from insufficient imaging resolution. We are developing techniques for imaging, reconstruction and analysis of neuronal morphology that capture both local and global structural variation. To minimize quantization error and evaluate more precisely the fine geometry of dendrites and spines, we introduce a new shape analysis technique, the Rayburst sampling algorithm that uses the original grayscale data rather than the segmented images for precise, continuous radius estimation, and multidirectional radius sampling to represent non-circular branch cross-sections and anisotropic structures such as dendritic spine heads, with greater accuracy. We apply the Rayburst technique to 3D neuronal shape analysis at different scales. We reconstruct and digitize entire neurons from stacks of laser-scanning microscopy images, as well as globally complex structures such as multineuron networks and microvascular networks. We also introduce imaging techniques necessary to recover detailed information on three-dimensional mass distribution and surface roughness of amyloid beta plaques from human Alzheimer's disease patients and from the Tg2576 mouse that expresses the "Swedish" mutation of the amyloid precursor protein. By providing true three-dimensional morphometry of complex histologic structures on multiple scales, the tools described in this report will enable multiscale biophysical modeling studies capable of testing potential mechanisms by which altered dendritic structure, spine geometry and network branching patterns that occur in normal aging and in many brain disorders, determine deficits of functions such as working memory and cognition.
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MESH Headings
- Aged
- Aged, 80 and over
- Alzheimer Disease/genetics
- Alzheimer Disease/pathology
- Animals
- Cell Size
- Diagnostic Imaging
- Disease Models, Animal
- Female
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Hippocampus/pathology
- Humans
- Imaging, Three-Dimensional
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Microscopy, Confocal/methods
- Microscopy, Electron, Scanning/methods
- Models, Anatomic
- Neurons/metabolism
- Neurons/pathology
- Neurons/ultrastructure
- Plaque, Amyloid/ultrastructure
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Affiliation(s)
- S L Wearne
- Computational Neurobiology and Imaging Center, Mount Sinai School of Medicine, New York, NY 10029-6574, USA.
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44
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Wang L, Wang Y, Han Y, Henderson SC, Majeska RJ, Weinbaum S, Schaffler MB. In situ measurement of solute transport in the bone lacunar-canalicular system. Proc Natl Acad Sci U S A 2005; 102:11911-11916. [PMID: 16087872 DOI: 10.1073/pnas.050519310] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2023] Open
Abstract
Solute transport through the bone lacunar-canalicular system is believed to be essential for osteocyte survival and function but has proved difficult to measure. We report an approach that permits direct measurement of real-time solute movement in intact bones. By using fluorescence recovery after photobleaching, the movement of a vitally injected fluorescent dye (sodium fluorescein) among individual osteocytic lacunae was visualized in situ beneath the periosteal surface of mouse cortical bone at depths up to 50 microm with laser scanning confocal microscopy. Transport was analyzed by using a two-compartment mathematical model of solute diffusion that accounted for the characteristic anatomical features of the lacunar-canalicular system. The diffusion coefficient of fluorescein (376 Da) was determined to be 3.3 +/- 0.6 x 10(-6) cm2/sec, which is 62% of its diffusion coefficient in water and is similar to diffusion coefficients measured for comparably sized molecules in cartilage. The diffusion of fluorescein in bone is also consistent with the presence of an osteocyte pericellular matrix whose structure resembles that proposed for the endothelial glycocalyx [Squire, J. M., Chew, M., Nneji, G., Neal, C., Barry, J. & Michel, C. (2001) J. Struct. Biol. 136, 239-255]. To our knowledge, this is the first instance where the dynamics of molecular movement has been measured directly in the bone lacunar-canalicular system. This in situ imaging approach should also facilitate the analysis of convection-based transport mechanisms in bones of living animals.
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Affiliation(s)
- Liyun Wang
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY 10029, USA.
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45
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Wang L, Wang Y, Han Y, Henderson SC, Majeska RJ, Weinbaum S, Schaffler MB. In situ measurement of solute transport in the bone lacunar-canalicular system. Proc Natl Acad Sci U S A 2005; 102:11911-6. [PMID: 16087872 PMCID: PMC1187997 DOI: 10.1073/pnas.0505193102] [Citation(s) in RCA: 165] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Solute transport through the bone lacunar-canalicular system is believed to be essential for osteocyte survival and function but has proved difficult to measure. We report an approach that permits direct measurement of real-time solute movement in intact bones. By using fluorescence recovery after photobleaching, the movement of a vitally injected fluorescent dye (sodium fluorescein) among individual osteocytic lacunae was visualized in situ beneath the periosteal surface of mouse cortical bone at depths up to 50 microm with laser scanning confocal microscopy. Transport was analyzed by using a two-compartment mathematical model of solute diffusion that accounted for the characteristic anatomical features of the lacunar-canalicular system. The diffusion coefficient of fluorescein (376 Da) was determined to be 3.3 +/- 0.6 x 10(-6) cm2/sec, which is 62% of its diffusion coefficient in water and is similar to diffusion coefficients measured for comparably sized molecules in cartilage. The diffusion of fluorescein in bone is also consistent with the presence of an osteocyte pericellular matrix whose structure resembles that proposed for the endothelial glycocalyx [Squire, J. M., Chew, M., Nneji, G., Neal, C., Barry, J. & Michel, C. (2001) J. Struct. Biol. 136, 239-255]. To our knowledge, this is the first instance where the dynamics of molecular movement has been measured directly in the bone lacunar-canalicular system. This in situ imaging approach should also facilitate the analysis of convection-based transport mechanisms in bones of living animals.
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Affiliation(s)
- Liyun Wang
- Leni and Peter W. May Department of Orthopaedics, Mount Sinai School of Medicine, New York, NY 10029, USA.
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46
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Butler A, Henderson SC, Gordon RE, Dagan A, Gatt S, Schuchman EH. Preimplantation diagnosis of a lysosomal storage disorder by in situ enzymatic activity: 'proof of principle' in acid sphingomyelinase-deficient mice. J Inherit Metab Dis 2005; 28:1-12. [PMID: 15702401 DOI: 10.1007/s10545-005-4418-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2004] [Accepted: 08/10/2004] [Indexed: 10/25/2022]
Abstract
Genetic diagnosis of preimplantation embryos (PGD) can substantially reduce the chance that at-risk couples have children afflicted with inherited diseases. However, PGD requires DNA,which is usually obtained from single cells following embryo biopsy. In addition, PGD requires that the genetic defect(s) causing the disorder be known. We have therefore developed an alternative to PGD, which we term preimplantation enzymatic diagnosis (PED). PED has several advantages over PGD, including the facts that it does not require embryo biopsy and that the gene defect(s) causing the disorder need not be known. We have demonstrated 'proof of principle' for this approach using embryos obtained from a mouse model (ASMKO mice) of acid sphingomyelinase (ASM)-deficient Niemann-Pick disease, an inherited lysosomal storage disorder. For this technique, fluorescently (BODIPY)-conjugated sphingomyelin was used to detect ASM activity in situ. Wild-type, preimplantation embryos degraded the substrate following a short 'pulse-chase' period, resulting in markedly reduced fluorescence compared to ASMKO embryos, which retained the fluorescent substrate. Thus, the two embryo types could be easily distinguished by fluorescent microscopy. The fluorescent sphingomyelin was not toxic to the embryos, and the entire procedure could be accomplished within 48 h without embryo biopsy. We suggest that PED may be useful for the preimplantation diagnosis of lysosomal storage disorders, and perhaps other enzymatic defects where similar in situ assay methods are available.
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Affiliation(s)
- A Butler
- Department of Human Genetics, Mount Sinai School of Medicine, 1425 Madision Avenue, New York, NY 10029, USA
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47
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Holstein GR, Martinelli GP, Henderson SC, Friedrich VL, Rabbitt RD, Highstein SM. Gamma-aminobutyric acid is present in a spatially discrete subpopulation of hair cells in the crista ampullaris of the toadfish Opsanus tau. J Comp Neurol 2004; 471:1-10. [PMID: 14983471 DOI: 10.1002/cne.11025] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although gamma-aminobutyric acid (GABA) and glutamate are known to be present in the vestibular sensory epithelia of a variety of species, the functional relationship between these two transmitters is not clear. The present study addresses the three-dimensional spatial distribution of GABA and glutamate immunoreactivity in the vestibular labyrinth of the oyster toadfish by using whole end organs labeled by immunofluorescence with monoclonal anti-GABA and/or antiglutamate antibodies and visualized as whole mounts by multiphoton confocal microscopy. We find glutamate-immunoreactive hair cells present throughout the sensory epithelium. In contrast, prominent GABA immunoreactivity is restricted to a small population of hair cells located in the central region of the crista. Double immunofluorescence reveals two distinct staining patterns in GABA-labeled hair cells. Most ( approximately 80%) GABA-labeled cells show trace levels of glutamate, appropriate for the metabolic/synthetic role of cytoplasmic glutamate. The remainder of the GABA-stained cells contain substantial levels of both GABA and glutamate, suggesting transmitter colocalization. In the toadfish utricle, glutamatergic hair cells are present throughout the macula. GABA-immunoreactive hair cells follow the arc of the striola, and most GABA-labeled receptor cells coexpress glutamate. The localization of GABA was explored in other species as well. In the pigeon, GABAergic hair cells are present throughout the crista ampullaris. Our findings demonstrate that multiple, neurochemically distinct types of hair cells are present in vestibular sensory epithelia. These observations, together with the excitatory activity generally associated with 8th nerve afferent fibers, strongly suggest that GABA serves an important, specific, and complex role in determining primary afferent response dynamics.
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Affiliation(s)
- Gay R Holstein
- Department of Neurology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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48
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Abstract
Transduction of proteins and other macromolecules constitutes a potent technology to analyze cell functions and to achieve therapeutic interventions. In general, fusion proteins with protein transduction domains, such as TAT, are produced in a bacterial expression system. Here we describe the generation of a mammalian expression vector coding for TAT-EGFP fusion protein. Transfection of CHO-K1 cells by this vector and subsequent selection by Zeocin resulted in cell lines that express and secrete EGFP, a variant of the green fluorescent protein GFP. The ultimate cell line was produced by first cloning the stable integrants and subsequent selection of EGFP-expressing cells by flow cytometric sorting. In the resulting cell line approximately 98% of cells express EGFP. Using the same methodology, we generated cell lines that express DsRed fluorescent protein. The advantages of using such a mammalian expression system include the ease of generating TAT fusion proteins and the potential for sustained production of such proteins in vitro and, potentially, in vivo.
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Affiliation(s)
- Tibor Barka
- Center for Anatomy and Functional Morphology and Department of Pathology, Mount Sinai School of Medicine, New York, New York 10029, USA.
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49
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Goldstein JL, Zhao SZ, Burke TA, Palmer R, von Allmen H, Henderson SC. Incidence of outpatient physician claims for upper gastrointestinal symptoms among new users of celecoxib, ibuprofen, and naproxen in an insured population in the United States. Am J Gastroenterol 2003; 98:2627-34. [PMID: 14687808 DOI: 10.1111/j.1572-0241.2003.08722.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE The aim of this study was to compare the risk of outpatient medical claims for UGI symptoms among new users of celecoxib versus ibuprofen, and naproxen. METHODS The study was conducted using LifeLink, an insurance claims database of approximately 1.8 million employees, dependents, and retirees in the United States. Patients newly treated with a prescription of celecoxib, ibuprofen, or naproxen between June 1, 1999, and June 30, 2001, were included. A patient with an upper GI (UGI) symptom was any individual with an outpatient physician claim for dyspepsia (ICD-9 = 536.8), abdominal pain (789.0), or nausea/vomiting (787.0). Incidence was determined using person-time analysis. Multivariate analyses were conducted using Poisson and Cox regression models. RESULTS The cohort consisted of patients prescribed celecoxib (n = 68,939), ibuprofen (n = 71,456), or naproxen (n = 50,014). At baseline, celecoxib users were older and more likely to have a history of UGI or cardiovascular conditions. The incidence rate of any UGI symptom was 0.46 per 1,000 patient-days for celecoxib, 0.70 for ibuprofen, and 0.62 for naproxen. After adjusting for confounding factors using Poisson regression, the ibuprofen rate was 48% higher than the celecoxib rate (incidence rate ratio (IRR) = 1.48; 95% CI = 1.39-1.58; p < 0.001), whereas the naproxen rate was 40% higher (IRR = 1.40; 95% CI = 1.31-1.49; p < 0.001). The association between drug use and UGI symptoms was confirmed by Cox regression analysis; the hazard ratios were 1.21 (95% CI = 1.13-1.29; p < 0.001) for ibuprofen and 1.15 (95% CI = 1.07-1.23; p < 0.001) for naproxen relative to celecoxib. Younger age, female sex, medical history of UGI, cardiovascular and renal conditions, and higher baseline average healthcare expenditures for the 12-month period preceding the index prescription were also significantly associated with an increased incidence of UGI symptoms. CONCLUSIONS Celecoxib use is associated with a significantly decreased risk of outpatient physician claims for UGI symptoms compared with commonly used prescription nonspecific nonsteroidal anti-inflammatory drugs.
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Affiliation(s)
- Jay L Goldstein
- Department of Medicine, Section of Digestive Diseases and Nutrition, College of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Henderson SC, Bamezai A. Loss of Ly-6A.2 expression on immature developing T cells in the thymus is necessary for their normal growth and generation of the Vbeta T-cell repertoire. Tissue Antigens 2003; 62:117-32. [PMID: 12889992 DOI: 10.1034/j.1399-0039.2003.00063.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Stage-specific expression of a number of cell-surface and signaling proteins is critical for normal development of T cells in the thymus. Equally important may be the loss of expression/signaling of developmentally regulated proteins for proper transitioning of developing T cells into thymic subsets. Ly-6A.2 exhibits a regulated pattern of expression on T cells maturing in the thymus, and dysregulating its expression results in arrest of developing T cells within the CD3-CD4-CD8- triple negative (TN) stage where the normal expression of Ly-6A.2 is extinguished. To further characterize the mechanisms underlying this block, we examined whether cell signaling and/or cell adhesion properties of the Ly-6A.2 molecule influenced the block in T-cell development. Analysis of bone marrow chimeras generated by injecting CFSE-labeled Ly-6A.2 transgenic bone marrow cells into irradiated syngeneic non-transgenic mice revealed normal trafficking of developing T cells from the cortex into the medulla. Production of LAT but not p56lck was diminished in CD4-CD8- DN cells from Ly-6A.2 dysregulated mice when compared with control littermates. Dysregulated expression of Ly-6A.2 did not suppress endogenous TCR-Vbeta expression. Finally, dysregulated expression of Ly-6A.2 enhanced apoptosis of an immature CD4+CD8+ (DP) subset of developing cells and altered the selected TCR-Vbeta repertoire. Taken together, these observations indicate that the termination of Ly-6A.2 expression and signaling within the CD4-CD8-CD3- subset of developing T cells is an important checkpoint during normal thymic development.
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Affiliation(s)
- S C Henderson
- Department of Cellular Biology, University of Georgia, Athens, GA, USA
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