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Padilla-Benavides T, Olea-Flores M, Sharma T, Syed SA, Witwicka H, Zuñiga-Eulogio MD, Zhang K, Navarro-Tito N, Imbalzano AN. Differential Contributions of mSWI/SNF Chromatin Remodeler Sub-Families to Myoblast Differentiation. Int J Mol Sci 2023; 24:11256. [PMID: 37511016 PMCID: PMC10378909 DOI: 10.3390/ijms241411256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 05/30/2023] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Mammalian SWI/SNF (mSWI/SNF) complexes are ATP-dependent chromatin remodeling enzymes that are critical for normal cellular functions. mSWI/SNF enzymes are classified into three sub-families based on the presence of specific subunit proteins. The sub-families are Brm- or Brg1-associated factor (BAF), ncBAF (non-canonical BAF), and polybromo-associated BAF (PBAF). The biological roles for the different enzyme sub-families are poorly described. We knocked down the expression of genes encoding unique subunit proteins for each sub-family, Baf250A, Brd9, and Baf180, which mark the BAF, ncBAF, and PBAF sub-families, respectively, and examined the requirement for each in myoblast differentiation. We found that Baf250A and the BAF complex were required to drive lineage-specific gene expression. KD of Brd9 delayed differentiation. However, while the Baf250A-dependent gene expression profile included myogenic genes, the Brd9-dependent gene expression profile did not, suggesting Brd9 and the ncBAF complex indirectly contributed to differentiation. Baf180 was dispensable for myoblast differentiation. The results distinguish between the roles of the mSWI/SNF enzyme sub-families during myoblast differentiation.
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Affiliation(s)
- Teresita Padilla-Benavides
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06459, USA; (M.O.-F.); (M.D.Z.-E.); (K.Z.)
| | - Monserrat Olea-Flores
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06459, USA; (M.O.-F.); (M.D.Z.-E.); (K.Z.)
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; (T.S.); (S.A.S.); (H.W.)
| | - Tapan Sharma
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; (T.S.); (S.A.S.); (H.W.)
| | - Sabriya A. Syed
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; (T.S.); (S.A.S.); (H.W.)
| | - Hanna Witwicka
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; (T.S.); (S.A.S.); (H.W.)
| | - Miriam D. Zuñiga-Eulogio
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06459, USA; (M.O.-F.); (M.D.Z.-E.); (K.Z.)
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo de los Bravo 39086, GRO, Mexico;
| | - Kexin Zhang
- Department of Molecular Biology and Biochemistry, Wesleyan University, Middletown, CT 06459, USA; (M.O.-F.); (M.D.Z.-E.); (K.Z.)
| | - Napoleon Navarro-Tito
- Facultad de Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Chilpancingo de los Bravo 39086, GRO, Mexico;
| | - Anthony N. Imbalzano
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA; (T.S.); (S.A.S.); (H.W.)
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2
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Sharma T, Robinson DCL, Witwicka H, Dilworth FJ, Imbalzano AN. The Bromodomains of the mammalian SWI/SNF (mSWI/SNF) ATPases Brahma (BRM) and Brahma Related Gene 1 (BRG1) promote chromatin interaction and are critical for skeletal muscle differentiation. Nucleic Acids Res 2021; 49:8060-8077. [PMID: 34289068 PMCID: PMC8373147 DOI: 10.1093/nar/gkab617] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/17/2021] [Accepted: 07/08/2021] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle regeneration is mediated by myoblasts that undergo epigenomic changes to establish the gene expression program of differentiated myofibers. mSWI/SNF chromatin remodeling enzymes coordinate with lineage-determining transcription factors to establish the epigenome of differentiated myofibers. Bromodomains bind to acetylated lysines on histone N-terminal tails and other proteins. The mutually exclusive ATPases of mSWI/SNF complexes, BRG1 and BRM, contain bromodomains with undefined functional importance in skeletal muscle differentiation. Pharmacological inhibition of mSWI/SNF bromodomain function using the small molecule PFI-3 reduced differentiation in cell culture and in vivo through decreased myogenic gene expression, while increasing cell cycle-related gene expression and the number of cells remaining in the cell cycle. Comparative gene expression analysis with data from myoblasts depleted of BRG1 or BRM showed that bromodomain function was required for a subset of BRG1- and BRM-dependent gene expression. Reduced binding of BRG1 and BRM after PFI-3 treatment showed that the bromodomain is required for stable chromatin binding at target gene promoters to alter gene expression. Our findings demonstrate that mSWI/SNF ATPase bromodomains permit stable binding of the mSWI/SNF ATPases to promoters required for cell cycle exit and establishment of muscle-specific gene expression.
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Affiliation(s)
- Tapan Sharma
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Daniel C L Robinson
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 8L6, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Hanna Witwicka
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - F Jeffrey Dilworth
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute, University of Ottawa, Ottawa, ON K1H 8L6, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Anthony N Imbalzano
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
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Meier JC, Tallant C, Fedorov O, Witwicka H, Hwang SY, van Stiphout RG, Lambert JP, Rogers C, Yapp C, Gerstenberger BS, Fedele V, Savitsky P, Heidenreich D, Daniels DL, Owen DR, Fish PV, Igoe NM, Bayle ED, Haendler B, Oppermann UC, Buffa F, Brennan PE, Müller S, Gingras AC, Odgren PR, Birnbaum MJ, Knapp S. Selective Targeting of Bromodomains of the Bromodomain-PHD Fingers Family Impairs Osteoclast Differentiation. ACS Chem Biol 2017; 12:2619-2630. [PMID: 28849908 PMCID: PMC5662925 DOI: 10.1021/acschembio.7b00481] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [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: 06/12/2017] [Accepted: 08/29/2017] [Indexed: 01/16/2023]
Abstract
Histone acetyltransferases of the MYST family are recruited to chromatin by BRPF scaffolding proteins. We explored functional consequences and the therapeutic potential of inhibitors targeting acetyl-lysine dependent protein interaction domains (bromodomains) present in BRPF1-3 in bone maintenance. We report three potent and selective inhibitors: one (PFI-4) with high selectivity for the BRPF1B isoform and two pan-BRPF bromodomain inhibitors (OF-1, NI-57). The developed inhibitors displaced BRPF bromodomains from chromatin and did not inhibit cell growth and proliferation. Intriguingly, the inhibitors impaired RANKL-induced differentiation of primary murine bone marrow cells and human primary monocytes into bone resorbing osteoclasts by specifically repressing transcriptional programs required for osteoclastogenesis. The data suggest a key role of BRPF in regulating gene expression during osteoclastogenesis, and the excellent druggability of these bromodomains may lead to new treatment strategies for patients suffering from bone loss or osteolytic malignant bone lesions.
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Affiliation(s)
- Julia C. Meier
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Cynthia Tallant
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Oleg Fedorov
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Hanna Witwicka
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Sung-Yong Hwang
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Ruud G. van Stiphout
- Department of Oncology, Oxford University, Old Road Campus Research Building, Oxford OX3 7DQ, United Kingdom
| | - Jean-Philippe Lambert
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Catherine Rogers
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Clarence Yapp
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Brian S. Gerstenberger
- Pfizer Worldwide Medicinal
Chemistry, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Vita Fedele
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Pavel Savitsky
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - David Heidenreich
- Goethe-University Frankfurt, Institute of Pharmaceutical Chemistry, Riedberg Campus, 60438 Frankfurt am Main, Germany
| | | | - Dafydd R. Owen
- Pfizer Worldwide Medicinal
Chemistry, 610 Main Street, Cambridge, Massachusetts 02139, United States
| | - Paul V. Fish
- Department
of Pharmaceutical & Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, United
Kingdom
| | - Niall M. Igoe
- Department
of Pharmaceutical & Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, United
Kingdom
| | - Elliott D. Bayle
- Department
of Pharmaceutical & Biological Chemistry, UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, United
Kingdom
| | - Bernard Haendler
- Drug Discovery, Bayer Pharma
AG, Müllerstrasse
178, D-13353 Berlin, Germany
| | | | - Francesca Buffa
- Department of Oncology, Oxford University, Old Road Campus Research Building, Oxford OX3 7DQ, United Kingdom
| | - Paul E. Brennan
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
| | - Susanne Müller
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
- Buchmann Institute for Life Sciences (BMLS), Riedberg Campus, 60438 Frankfurt am Main, Germany
| | - Anne Claude Gingras
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Paul R. Odgren
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, United States
| | - Mark J. Birnbaum
- Department of Biology, Merrimack College, North Andover, Massachusetts, United States
| | - Stefan Knapp
- Target Discovery
Institute and Structural Genomics Consortium, Oxford University, Oxford, United Kingom
- Buchmann Institute for Life Sciences (BMLS), Riedberg Campus, 60438 Frankfurt am Main, Germany
- Goethe-University Frankfurt, Institute of Pharmaceutical Chemistry, Riedberg Campus, 60438 Frankfurt am Main, Germany
- German Cancer Network (DKTK), Frankfurt site, 60438 Frankfurt am Main, Germany
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Odgren PR, Witwicka H, Reyes-Gutierrez P. The cast of clasts: catabolism and vascular invasion during bone growth, repair, and disease by osteoclasts, chondroclasts, and septoclasts. Connect Tissue Res 2016; 57:161-74. [PMID: 26818783 PMCID: PMC4912663 DOI: 10.3109/03008207.2016.1140752] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Three named cell types degrade and remove skeletal tissues during growth, repair, or disease: osteoclasts, chondroclasts, and septoclasts. A fourth type, unnamed and less understood, removes nonmineralized cartilage during development of secondary ossification centers. "Osteoclasts," best known and studied, are polykaryons formed by fusion of monocyte precursors under the influence of colony stimulating factor 1 (CSF)-1 (M-CSF) and RANKL. They resorb bone during growth, remodeling, repair, and disease. "Chondroclasts," originally described as highly similar in cytological detail to osteoclasts, reside on and degrade mineralized cartilage. They may be identical to osteoclasts since to date there are no distinguishing markers for them. Because osteoclasts also consume cartilage cores along with bone during growth, the term "chondroclast" might best be reserved for cells attached only to cartilage. "Septoclasts" are less studied and appreciated. They are mononuclear perivascular cells rich in cathepsin B. They extend a cytoplasmic projection with a ruffled membrane and degrade the last transverse septum of hypertrophic cartilage in the growth plate, permitting capillaries to bud into it. To do this, antiangiogenic signals in cartilage must give way to vascular trophic factors, mainly vascular endothelial growth factor (VEGF). The final cell type excavates cartilage canals for vascular invasion of articular cartilage during development of secondary ossification centers. The "clasts" are considered in the context of fracture repair and diseases such as arthritis and tumor metastasis. Many observations support an essential role for hypertrophic chondrocytes in recruiting septoclasts and osteoclasts/chondroclasts by supplying VEGF and RANKL. The intimate relationship between blood vessels and skeletal turnover and repair is also examined.
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Affiliation(s)
- Paul R. Odgren
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655,Corresponding author: Department of Cell and Developmental Biology, University of Massachusetts Medical School, 55 Lake Avenue, North, Worcester, MA 01655, USA, Phone: 508 856 8609, Fax: 508 856 1033,
| | - Hanna Witwicka
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Pablo Reyes-Gutierrez
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA 01655
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Witwicka H, Hwang SY, Reyes-Gutierrez P, Jia H, Odgren PE, Donahue LR, Birnbaum MJ, Odgren PR. Studies of OC-STAMP in Osteoclast Fusion: A New Knockout Mouse Model, Rescue of Cell Fusion, and Transmembrane Topology. PLoS One 2015; 10:e0128275. [PMID: 26042409 PMCID: PMC4456411 DOI: 10.1371/journal.pone.0128275] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [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: 11/11/2014] [Accepted: 04/23/2015] [Indexed: 11/29/2022] Open
Abstract
The fusion of monocyte/macrophage lineage cells into fully active, multinucleated, bone resorbing osteoclasts is a complex cell biological phenomenon that utilizes specialized proteins. OC-STAMP, a multi-pass transmembrane protein, has been shown to be required for pre-osteoclast fusion and for optimal bone resorption activity. A previously reported knockout mouse model had only mononuclear osteoclasts with markedly reduced resorption activity in vitro, but with paradoxically normal skeletal micro-CT parameters. To further explore this and related questions, we used mouse ES cells carrying a gene trap allele to generate a second OC-STAMP null mouse strain. Bone histology showed overall normal bone form with large numbers of TRAP-positive, mononuclear osteoclasts. Micro-CT parameters were not significantly different between knockout and wild type mice at 2 or 6 weeks old. At 6 weeks, metaphyseal TRAP-positive areas were lower and mean size of the areas were smaller in knockout femora, but bone turnover markers in serum were normal. Bone marrow mononuclear cells became TRAP-positive when cultured with CSF-1 and RANKL, but they did not fuse. Expression levels of other osteoclast markers, such as cathepsin K, carbonic anhydrase II, and NFATc1, were not significantly different compared to wild type. Actin rings were present, but small, and pit assays showed a 3.5-fold decrease in area resorbed. Restoring OC-STAMP in knockout cells by lentiviral transduction rescued fusion and resorption. N- and C-termini of OC-STAMP were intracellular, and a predicted glycosylation site was shown to be utilized and to lie on an extracellular loop. The site is conserved in all terrestrial vertebrates and appears to be required for protein stability, but not for fusion. Based on this and other results, we present a topological model of OC-STAMP as a 6-transmembrane domain protein. We also contrast the osteoclast-specific roles of OC- and DC-STAMP with more generalized cell fusion mechanisms.
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Affiliation(s)
- Hanna Witwicka
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Sung-Yong Hwang
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Pablo Reyes-Gutierrez
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Hong Jia
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
| | - Paul E. Odgren
- Parallax Pictures, Princeton, MA, United States of America
| | - Leah Rae Donahue
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Mark J. Birnbaum
- Department of Biology, Merrimack College, North Andover, MA, United States of America
| | - Paul R. Odgren
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, MA, United States of America
- * E-mail:
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Witwicka H, Jia H, Kutikov A, Reyes-Gutierrez P, Li X, Odgren PR. TRAFD1 (FLN29) Interacts with Plekhm1 and Regulates Osteoclast Acidification and Resorption. PLoS One 2015; 10:e0127537. [PMID: 25992615 PMCID: PMC4438057 DOI: 10.1371/journal.pone.0127537] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [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: 02/18/2015] [Accepted: 04/16/2015] [Indexed: 02/07/2023] Open
Abstract
Plekhm1 is a large, multi-modular, adapter protein implicated in osteoclast vesicle trafficking and bone resorption. In patients, inactivating mutations cause osteopetrosis, and gain-of-function mutations cause osteopenia. Investigations of potential Plekhm1 interaction partners by mass spectrometry identified TRAFD1 (FLN29), a protein previously shown to suppress toll-like receptor signaling in monocytes/macrophages, thereby dampening inflammatory responses to innate immunity. We mapped the binding domains to the TRAFD1 zinc finger (aa 37-60), and to the region of Plekhm1 between its second pleckstrin homology domain and its C1 domain (aa 784-986). RANKL slightly increased TRAFD1 levels, particularly in primary osteoclasts, and the co-localization of TRAFD1 with Plekhm1 also increased with RANKL treatment. Stable knockdown of TRAFD1 in RAW 264.7 cells inhibited resorption activity proportionally to the degree of knockdown, and inhibited acidification. The lack of acidification occurred despite the presence of osteoclast acidification factors including carbonic anhydrase II, a3-V-ATPase, and the ClC7 chloride channel. Secretion of TRAP and cathepsin K were also markedly inhibited in knockdown cells. Truncated Plekhm1 in ia/ia osteopetrotic rat cells prevented vesicle localization of Plekhm1 and TRAFD1. We conclude that TRAFD1, in association with Plekhm1/Rab7-positive late endosomes-early lysosomes, has a previously unknown role in vesicle trafficking, acidification, and resorption in osteoclasts.
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Affiliation(s)
- Hanna Witwicka
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
| | - Hong Jia
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
| | - Artem Kutikov
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
| | - Pablo Reyes-Gutierrez
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
| | - Xiangdong Li
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
| | - Paul R. Odgren
- Department of Cell and Developmental Biology, University of Massachusetts Medical School, Worcester, Massachusetts, 01655 United States of America
- * E-mail:
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Birnbaum MJ, Picco J, Clements M, Witwicka H, Yang M, Hoey MT, Odgren PR. Using osteoclast differentiation as a model for gene discovery in an undergraduate cell biology laboratory. Biochem Mol Biol Educ 2010; 38:385-392. [PMID: 21567867 PMCID: PMC4090094 DOI: 10.1002/bmb.20433] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A key goal of molecular/cell biology/biotechnology is to identify essential genes in virtually every physiological process to uncover basic mechanisms of cell function and to establish potential targets of drug therapy combating human disease. This article describes a semester-long, project-oriented molecular/cellular/biotechnology laboratory providing students, within a framework of bone cell biology, with a modern approach to gene discovery. Students are introduced to the topics of bone cells, bone synthesis, bone resorption, and osteoporosis. They then review the theory of microchip gene arrays, and study microchip array data generated during the differentiation of bone-resorbing osteoclasts in vitro. The class selects genes whose expression increases during osteoclastogenesis, and researches them in small groups using web-based bioinformatics tools. Students then go to a biotechnology company website to find and order small inhibitory RNAs (siRNAs) designed to "knockdown" expression of the gene of interest. Students then learn to transfect these siRNAs into osteoclasts, stimulate the cells to differentiate, assay osteoclast differentiation in vitro, and measure specific gene expression using real-time PCR and immunoblotting. Specific siRNA knockdown resulting in a decrease in osteoclastogenesis is indicative of a gene's physiological relevance. The results are analyzed statistically and presented to the class in groups. In the past 2 years, students identified several genes essential for optimal osteoclast differentiation, including Myo1d. The students hypothesize that the myo1d protein functions in osteoclasts to deliver important proteins to the cell surface via vesicular transport along microfilaments. Student response to the new course was overwhelmingly positive.
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Affiliation(s)
- Mark J Birnbaum
- Department of Biology, Merrimack College, North Andover, Massachusetts 01845, USA.
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8
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Ciuman M, Siednienko J, Czyzyk R, Witwicka H, Kołosionek E, Kobiałka M, Gorczyca WA. Cyclic GMP-dependent protein kinase and soluble guanylyl cyclase disappear in elicited rat neutrophils. Biochim Biophys Acta Gen Subj 2006; 1760:1618-23. [PMID: 17045402 DOI: 10.1016/j.bbagen.2006.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Revised: 07/24/2006] [Accepted: 09/05/2006] [Indexed: 10/24/2022]
Abstract
The nitric oxide/soluble guanylyl cyclase/cGMP-dependent protein kinase (NO/sGC/PKG) cascade has been shown to affect important functions of circulating neutrophils. We demonstrate that neutrophils isolated from rats treated intraperitoneally with peptone protease cannot use this signaling pathway. Although PKG was detected at both the mRNA and protein levels in peripheral blood neutrophils (PBNs) of control rats, it was expressed neither in PBNs nor in peritoneal exudate neutrophils (PENs) of provoked rats. Also, mRNA of the alpha and beta chains of heterodimeric sGC was present in PBNs, but absent in PENs. Consistently, PBNs responded to activators of sGC with cGMP synthesis, while PENs did not. These results showed that neutrophils recruited by a provoking agent lost PKG and, in the case of PENs, also sGC and thus the capacity to respond to NO with cGMP signaling. We speculate that such downregulation of the sGC/PKG pathway is likely a result of the high activity of inducible NO synthase observed in inflammatory neutrophils.
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Affiliation(s)
- Małgorzata Ciuman
- Laboratory of Signaling Proteins, L. Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114 Wrocław, Poland
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9
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Witwicka H, Kobiałka M, Siednienko J, Mitkiewicz M, Gorczyca WA. Expression and activity of cGMP-dependent phosphodiesterases is up-regulated by lipopolysaccharide (LPS) in rat peritoneal macrophages. Biochim Biophys Acta 2006; 1773:209-18. [PMID: 17141339 DOI: 10.1016/j.bbamcr.2006.10.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2006] [Revised: 10/15/2006] [Accepted: 10/17/2006] [Indexed: 12/21/2022]
Abstract
It has been shown that cyclic GMP (cGMP) modulates the inflammatory responses of macrophages, but the underlying molecular mechanisms are still poorly understood. Looking for proteins potentially regulated by cGMP in rat peritoneal macrophages (PMs), in this study we analyzed expression and activity of cGMP-hydrolyzing and cGMP-regulated phosphodiesterases (PDEs). It was found that freshly isolated peritoneal exudate macrophages (PEMs) express enzymes belonging to families PDE1-3, PDE5, PDE10, and PDE11. Analysis of substrate specificity, sensitivity to inhibitors, and subcellular localization showed that PDE2 and PDE3 are the main cGMP-regulated PDE isoforms in PEMs. The profile of PDE expression was altered by maintaining PEMs in culture and treatment with bacterial endotoxin (LPS). After 24 h culture, PDE5 was not present and the levels of PDE2, PDE3, and PDE11 were markedly decreased. However, their expression and activity was recovered after treatment of cultured cells with LPS. A similar pattern of changes was observed for the expression of TNFalpha, but not for guanylyl cyclase A (GC-A). LPS up-regulated PDE expression also in resident peritoneal macrophages (RPMs), although not all PDEs present in PEMs were detected in RPMs. Taken together, our results show that in rat PMs expression of cGMP-dependent PDEs positively correlates with the activation state of cells. Moreover, the fact that most of these PDEs hydrolyze also cAMP indicates that cGMP can play a role of potent regulator of cAMP signaling in macrophages.
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Affiliation(s)
- Hanna Witwicka
- Laboratory of Signaling Proteins, L. Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, R. Weigla 12, 53-114 Wrocław, Poland
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Siednienko J, Ciuman M, Witwicka H, Gorczyca WA. Activation of NF-κB by nitric oxide/cGMP in human blood CD14+ cells. BMC Pharmacol 2005. [DOI: 10.1186/1471-2210-5-s1-p51] [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: 11/10/2022] Open
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Abstract
The aim of our studies was to establish which enzymes constitute the "cGMP pathway" in rat and guinea pig peritoneal macrophages (PM). We found that in guinea pig PM synthesis of the nucleotide was significantly enhanced in response to activators of soluble guanylyl cyclase (sGC) and it was only slightly stimulated by specific activators of particulate guanylyl cyclases (pGC). In contrast, rat PM responded strongly to atrial natriuretic peptide (ANP), the activator of pGC type A. The rat cells synthesized about three-fold more cGMP than an equal number of the guinea pig cells. The activity of phosphodiesterases (PDE) hydrolyzing cGMP was apparently regulated by cGMP itself in PM of both species and again it was higher in the rat cells than in those isolated from guinea pig. However, guinea pig PM revealed an activity of Ca(2+)/calmodulin-dependent PDE1, which was absent in the rat cells. Using Western blotting analysis we were unable to detect the presence of cGMP-dependent protein kinase 1 (PKG1) in PM isolated from either species. In summary, our findings indicate that particulate GC-A is the main active form of GC in the rat PM, while in guinea pig macrophages the sGC activity dominates. Since the profiles of the PDE activities in rat and guinea pig PM are also different, we conclude that the mechanisms regulating cGMP metabolism in PM are species-specific. Moreover, our results suggest that targets for cGMP other than PKG1 should be present in PM of both species.
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Kobiałka M, Witwicka H, Siednienko J, Gorczyca WA. Metabolism of cyclic GMP in peritoneal macrophages of rat and guinea pig. Acta Biochim Pol 2003; 50:837-848. [PMID: 14515164] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2003] [Revised: 08/07/2003] [Accepted: 08/12/2003] [Indexed: 05/24/2023]
Abstract
The aim of our studies was to establish which enzymes constitute the "cGMP pathway" in rat and guinea pig peritoneal macrophages (PM). We found that in guinea pig PM synthesis of the nucleotide was significantly enhanced in response to activators of soluble guanylyl cyclase (sGC) and it was only slightly stimulated by specific activators of particulate guanylyl cyclases (pGC). In contrast, rat PM responded strongly to atrial natriuretic peptide (ANP), the activator of pGC type A. The rat cells synthesized about three-fold more cGMP than an equal number of the guinea pig cells. The activity of phosphodiesterases (PDE) hydrolyzing cGMP was apparently regulated by cGMP itself in PM of both species and again it was higher in the rat cells than in those isolated from guinea pig. However, guinea pig PM revealed an activity of Ca(2+)/calmodulin-dependent PDE1, which was absent in the rat cells. Using Western blotting analysis we were unable to detect the presence of cGMP-dependent protein kinase 1 (PKG1) in PM isolated from either species. In summary, our findings indicate that particulate GC-A is the main active form of GC in the rat PM, while in guinea pig macrophages the sGC activity dominates. Since the profiles of the PDE activities in rat and guinea pig PM are also different, we conclude that the mechanisms regulating cGMP metabolism in PM are species-specific. Moreover, our results suggest that targets for cGMP other than PKG1 should be present in PM of both species.
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Affiliation(s)
- Marcin Kobiałka
- Laboratory of Signaling Proteins, L. Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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Abstract
Intact rat peritoneal macrophages (rPM) treated with 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases (PDEs), accumulated more cGMP than untreated cells. A PDE activity toward [(3)H]cGMP was detected in the soluble and particulate fractions of rPM. The hydrolysis of cGMP was Ca(2+)/calmodulin-independent but increased in the presence of cGMP excess. Similar results were obtained when [(3)H]cAMP was used as a substrate. The hydrolytic activity towards both nucleotides was inhibited in the presence of IBMX. Therefore, the PDEs of families 2, 5, 10 and 11 are potential candidates for cGMP hydrolysis in the rPM. They may not only regulate the cGMP level in a feedback-controlled way but also link cGMP-dependent pathways with those regulated by cAMP.
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Witwicka H, Kobiałka M, Gorczyca WA. Hydrolysis of cyclic GMP in rat peritoneal macrophages. Acta Biochim Pol 2002; 49:891-897. [PMID: 12545195] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2002] [Revised: 11/20/2002] [Accepted: 11/21/2002] [Indexed: 05/24/2023]
Abstract
Intact rat peritoneal macrophages (rPM) treated with 3-isobutyl-1-methylxanthine (IBMX), an inhibitor of phosphodiesterases (PDEs), accumulated more cGMP than untreated cells. A PDE activity toward [(3)H]cGMP was detected in the soluble and particulate fractions of rPM. The hydrolysis of cGMP was Ca(2+)/calmodulin-independent but increased in the presence of cGMP excess. Similar results were obtained when [(3)H]cAMP was used as a substrate. The hydrolytic activity towards both nucleotides was inhibited in the presence of IBMX. Therefore, the PDEs of families 2, 5, 10 and 11 are potential candidates for cGMP hydrolysis in the rPM. They may not only regulate the cGMP level in a feedback-controlled way but also link cGMP-dependent pathways with those regulated by cAMP.
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Affiliation(s)
- Hanna Witwicka
- Laboratory of Signaling Proteins, L Hirszfeld Institute of Immunology and Experimental Therapy, Polish Academy of Sciences, Wrocław, Poland
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