51
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Gudde AEEG, González-Barriga A, van den Broek WJAA, Wieringa B, Wansink DG. A low absolute number of expanded transcripts is involved in myotonic dystrophy type 1 manifestation in muscle. Hum Mol Genet 2016; 25:1648-62. [PMID: 26908607 PMCID: PMC4805313 DOI: 10.1093/hmg/ddw042] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 02/09/2016] [Indexed: 12/15/2022] Open
Abstract
Muscular manifestation of myotonic dystrophy type 1 (DM1), a common inheritable degenerative multisystem disorder, is mainly caused by expression of RNA from a (CTG·CAG)n-expanded DM1 locus. Here, we report on comparative profiling of expression of normal and expanded endogenous or transgenic transcripts in skeletal muscle cells and biopsies from DM1 mouse models and patients in order to help us in understanding the role of this RNA-mediated toxicity. In tissue of HSALR mice, the most intensely used ‘muscle-only’ model in the DM1 field, RNA from the α-actin (CTG)250 transgene was at least 1000-fold more abundant than that from the Dmpk gene, or the DMPK gene in humans. Conversely, the DMPK transgene in another line, DM500/DMSXL mice, was expressed ∼10-fold lower than the endogenous gene. Temporal regulation of expanded RNA expression differed between models. Onset of expression occurred remarkably late in HSALR myoblasts during in vitro myogenesis whereas Dmpk or DMPK (trans)genes were expressed throughout proliferation and differentiation phases. Importantly, quantification of absolute transcript numbers revealed that normal and expanded Dmpk/DMPK transcripts in mouse models and DM1 patients are low-abundance RNA species. Northern blotting, reverse transcriptase–quantitative polymerase chain reaction, RNA-sequencing and fluorescent in situ hybridization analyses showed that they occur at an absolute number between one and a few dozen molecules per cell. Our findings refine the current RNA dominance theory for DM1 pathophysiology, as anomalous factor binding to expanded transcripts and formation of soluble or insoluble ribonucleoprotein aggregates must be nucleated by only few expanded DMPK transcripts and therefore be a small numbers game.
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Affiliation(s)
- Anke E E G Gudde
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Anchel González-Barriga
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Walther J A A van den Broek
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Bé Wieringa
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Derick G Wansink
- Department of Cell Biology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
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52
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Escobar H, Schöwel V, Spuler S, Marg A, Izsvák Z. Full-length Dysferlin Transfer by the Hyperactive Sleeping Beauty Transposase Restores Dysferlin-deficient Muscle. MOLECULAR THERAPY. NUCLEIC ACIDS 2016; 5:e277. [PMID: 26784637 PMCID: PMC5012550 DOI: 10.1038/mtna.2015.52] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 11/13/2015] [Indexed: 12/18/2022]
Abstract
Dysferlin-deficient muscular dystrophy is a progressive disease characterized by muscle weakness and wasting for which there is no treatment. It is caused by mutations in DYSF, a large, multiexonic gene that forms a coding sequence of 6.2 kb. Sleeping Beauty (SB) transposon is a nonviral gene transfer vector, already used in clinical trials. The hyperactive SB system consists of a transposon DNA sequence and a transposase protein, SB100X, that can integrate DNA over 10 kb into the target genome. We constructed an SB transposon-based vector to deliver full-length human DYSF cDNA into dysferlin-deficient H2K A/J myoblasts. We demonstrate proper dysferlin expression as well as highly efficient engraftment (>1,100 donor-derived fibers) of the engineered myoblasts in the skeletal muscle of dysferlin- and immunodeficient B6.Cg-Dysf(prmd) Prkdc(scid)/J (Scid/BLA/J) mice. Nonviral gene delivery of full-length human dysferlin into muscle cells, along with a successful and efficient transplantation into skeletal muscle are important advances towards successful gene therapy of dysferlin-deficient muscular dystrophy.
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Affiliation(s)
- Helena Escobar
- Mobile DNA, Max Delbrück Center for Molecular Medicine of the Helmholtz Society, Berlin, Germany
| | - Verena Schöwel
- Muscle Research Unit, Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité, Universitätsmedizin Berlin and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Simone Spuler
- Muscle Research Unit, Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité, Universitätsmedizin Berlin and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Andreas Marg
- Muscle Research Unit, Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité, Universitätsmedizin Berlin and the Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Zsuzsanna Izsvák
- Mobile DNA, Max Delbrück Center for Molecular Medicine of the Helmholtz Society, Berlin, Germany
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53
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Le BT, Filichev VV, Veedu RN. Investigation of twisted intercalating nucleic acid (TINA)-modified antisense oligonucleotides for splice modulation by induced exon-skipping in vitro. RSC Adv 2016. [DOI: 10.1039/c6ra22346j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
We have investigated the applicability of twisted intercalating nucleic acids (TINA)-modified antisense oligonucleotides (AOs) in exon skipping. We found that TINA-modified AOs induced exon skipping.
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Affiliation(s)
- Bao T. Le
- Centre for Comparative Genomics
- Murdoch University
- Perth 6150
- Australia
- Western Australian Neuroscience Research Institute
| | | | - Rakesh N. Veedu
- Centre for Comparative Genomics
- Murdoch University
- Perth 6150
- Australia
- Western Australian Neuroscience Research Institute
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54
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Blat Y, Blat S. Drug Discovery of Therapies for Duchenne Muscular Dystrophy. ACTA ACUST UNITED AC 2015; 20:1189-203. [PMID: 25975656 DOI: 10.1177/1087057115586535] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/21/2015] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a genetic, lethal, muscle disorder caused by the loss of the muscle protein, dystrophin, leading to progressive loss of muscle fibers and muscle weakness. Drug discovery efforts targeting DMD have used two main approaches: (1) the restoration of dystrophin expression or the expression of a compensatory protein, and (2) the mitigation of downstream pathological mechanisms, including dysregulated calcium homeostasis, oxidative stress, inflammation, fibrosis, and muscle ischemia. The aim of this review is to introduce the disease, its pathophysiology, and the available research tools to a drug discovery audience. This review will also detail the most promising therapies that are currently being tested in clinical trials or in advanced preclinical models.
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Affiliation(s)
| | - Shachar Blat
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, USA
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55
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Onopiuk M, Brutkowski W, Young C, Krasowska E, Róg J, Ritso M, Wojciechowska S, Arkle S, Zabłocki K, Górecki DC. Store-operated calcium entry contributes to abnormal Ca²⁺ signalling in dystrophic mdx mouse myoblasts. Arch Biochem Biophys 2015; 569:1-9. [PMID: 25659883 DOI: 10.1016/j.abb.2015.01.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 01/20/2015] [Accepted: 01/28/2015] [Indexed: 01/13/2023]
Abstract
Sarcolemma damage and activation of various calcium channels are implicated in altered Ca(2+) homeostasis in muscle fibres of both Duchenne muscular dystrophy (DMD) sufferers and in the mdx mouse model of DMD. Previously we have demonstrated that also in mdx myoblasts extracellular nucleotides trigger elevated cytoplasmic Ca(2+) concentrations due to alterations of both ionotropic and metabotropic purinergic receptors. Here we extend these findings to show that the mdx mutation is associated with enhanced store-operated calcium entry (SOCE). Substantially increased rate of SOCE in mdx myoblasts in comparison to that in control cells correlated with significantly elevated STIM1 protein levels. These results reveal that mutation in the dystrophin-encoding Dmd gene may significantly impact cellular calcium response to metabotropic stimulation involving depletion of the intracellular calcium stores followed by activation of the store-operated calcium entry, as early as in undifferentiated myoblasts. These data are in agreement with the increasing number of reports showing that the dystrophic pathology resulting from dystrophin mutations may be developmentally regulated. Moreover, our results showing that aberrant responses to extracellular stimuli may contribute to DMD pathogenesis suggest that treatments inhibiting such responses might alter progression of this lethal disease.
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Affiliation(s)
- Marta Onopiuk
- Nencki Institute of Experimental Biology, Warsaw, Poland; Departments of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA(1)
| | - Wojciech Brutkowski
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK; Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Christopher Young
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | - Elżbieta Krasowska
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK; Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Justyna Róg
- Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Morten Ritso
- Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | | | - Stephen Arkle
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
| | | | - Dariusz C Górecki
- School of Pharmacy and Biomedical Sciences, University of Portsmouth, Portsmouth, UK
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56
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Järver P, Zaghloul EM, Arzumanov AA, Saleh AF, McClorey G, Hammond SM, Hällbrink M, Langel Ü, Smith CIE, Wood MJA, Gait MJ, El Andaloussi S. Peptide nanoparticle delivery of charge-neutral splice-switching morpholino oligonucleotides. Nucleic Acid Ther 2015; 25:65-77. [PMID: 25594433 PMCID: PMC4376484 DOI: 10.1089/nat.2014.0511] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Oligonucleotide analogs have provided novel therapeutics targeting various disorders. However, their poor cellular uptake remains a major obstacle for their clinical development. Negatively charged oligonucleotides, such as 2′-O-Methyl RNA and locked nucleic acids have in recent years been delivered successfully into cells through complex formation with cationic polymers, peptides, liposomes, or similar nanoparticle delivery systems. However, due to the lack of electrostatic interactions, this promising delivery method has been unsuccessful to date using charge-neutral oligonucleotide analogs. We show here that lipid-functionalized cell-penetrating peptides can be efficiently exploited for cellular transfection of the charge-neutral oligonucleotide analog phosphorodiamidate morpholino. The lipopeptides form complexes with splice-switching phosphorodiamidate morpholino oligonucleotide and can be delivered into clinically relevant cell lines that are otherwise difficult to transfect while retaining biological activity. To our knowledge, this is the first study to show delivery through complex formation of biologically active charge-neutral oligonucleotides by cationic peptides.
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Affiliation(s)
- Peter Järver
- 1 Medical Research Council , Laboratory of Molecular Biology, Cambridge Biomedical Campus, Cambridge, United Kingdom
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57
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Correlating In Vitro Splice Switching Activity With Systemic In Vivo Delivery Using Novel ZEN-modified Oligonucleotides. MOLECULAR THERAPY-NUCLEIC ACIDS 2014; 3:e212. [PMID: 25423116 PMCID: PMC4459549 DOI: 10.1038/mtna.2014.63] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/20/2014] [Indexed: 01/16/2023]
Abstract
Splice switching oligonucleotides (SSOs) induce alternative splicing of pre-mRNA and typically employ chemical modifications to increase nuclease resistance and binding affinity to target pre-mRNA. Here we describe a new SSO non-base modifier (a naphthyl-azo group, "ZEN™") to direct exon exclusion in mutant dystrophin pre-mRNA to generate functional dystrophin protein. The ZEN modifier is placed near the ends of a 2'-O-methyl (2'OMe) oligonucleotide, increasing melting temperature and potency over unmodified 2'OMe oligonucleotides. In cultured H2K cells, a ZEN-modified 2'OMe phosphorothioate (PS) oligonucleotide delivered by lipid transfection greatly enhanced dystrophin exon skipping over the same 2'OMePS SSO lacking ZEN. However, when tested using free gymnotic uptake in vitro and following systemic delivery in vivo in dystrophin deficient mdx mice, the same ZEN-modified SSO failed to enhance potency. Importantly, we show for the first time that in vivo activity of anionic SSOs is modelled in vitro only when using gymnotic delivery. ZEN is thus a novel modifier that enhances activity of SSOs in vitro but will require improved delivery methods before its in vivo clinical potential can be realized.
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58
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Molt S, Bührdel JB, Yakovlev S, Schein P, Orfanos Z, Kirfel G, Winter L, Wiche G, van der Ven PFM, Rottbauer W, Just S, Belkin AM, Fürst DO. Aciculin interacts with filamin C and Xin and is essential for myofibril assembly, remodeling and maintenance. J Cell Sci 2014; 127:3578-92. [PMID: 24963132 DOI: 10.1242/jcs.152157] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Filamin C (FLNc) and Xin actin-binding repeat-containing proteins (XIRPs) are multi-adaptor proteins that are mainly expressed in cardiac and skeletal muscles and which play important roles in the assembly and repair of myofibrils and their attachment to the membrane. We identified the dystrophin-binding protein aciculin (also known as phosphoglucomutase-like protein 5, PGM5) as a new interaction partner of FLNc and Xin. All three proteins colocalized at intercalated discs of cardiac muscle and myotendinous junctions of skeletal muscle, whereas FLNc and aciculin also colocalized in mature Z-discs. Bimolecular fluorescence complementation experiments in developing cultured mammalian skeletal muscle cells demonstrated that Xin and aciculin also interact in FLNc-containing immature myofibrils and areas of myofibrillar remodeling and repair induced by electrical pulse stimulation (EPS). Fluorescence recovery after photobleaching (FRAP) experiments showed that aciculin is a highly dynamic and mobile protein. Aciculin knockdown in myotubes led to failure in myofibril assembly, alignment and membrane attachment, and a massive reduction in myofibril number. A highly similar phenotype was found upon depletion of aciculin in zebrafish embryos. Our results point to a thus far unappreciated, but essential, function of aciculin in myofibril formation, maintenance and remodeling.
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Affiliation(s)
- Sibylle Molt
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - John B Bührdel
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Sergiy Yakovlev
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Peter Schein
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | | | - Gregor Kirfel
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Lilli Winter
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Gerhard Wiche
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | | | - Wolfgang Rottbauer
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Steffen Just
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Alexey M Belkin
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Dieter O Fürst
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
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59
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Hildyard JCW, Wells DJ. Identification and validation of quantitative PCR reference genes suitable for normalizing expression in normal and dystrophic cell culture models of myogenesis. PLOS CURRENTS 2014; 6. [PMID: 24634799 PMCID: PMC3948689 DOI: 10.1371/currents.md.faafdde4bea8df4aa7d06cd5553119a6] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The coordinated differentiation of myoblasts to mature muscle is essential for muscle development and repair, and study of the myogenic program in health and disease is critical to the understanding and treatment of muscle pathologies. Use of quantitative RT-PCR to analyse gene expression in cell culture models of muscle differentiation can be highly informative, but data must be normalized to one or more suitable reference genes. Myogenesis is highly dynamic, thus identification of genes with stable expression throughout this process is challenging. Establishing a common set of reference genes suitable for measuring expression in both healthy and disease models would be of considerable advantage. We measured expression of 11 candidate normalization genes (Cdc40, Htatsf1, Ap3d1, Csnk2a2, Fbxw2, Fbxo38, Pak1ip1, Zfp91, GAPDH, ActB, 18S) in three cell culture models of myogenesis (C2C12 , H2K2B4, and the dystrophic line H2KSF1). Strong and weak normalization candidates were identified using the software packages Bestkeeper, geNorm and Normfinder, then validated against several known myogenic markers (MyoD, myogenin, MEF2C, dystrophin). Our data show that Csnk2a2 and Ap3d1 are suitable for normalizing gene expression during differentiation in both healthy and dystrophic cell-culture models, and that the commonly-used reference standards 18S, ActB and GAPDH are exceptionally poor candidates.
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Affiliation(s)
- John C W Hildyard
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, London, UK
| | - Dominic J Wells
- Department of Comparative and Biomedical Sciences, Royal Veterinary College, London, UK
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60
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Bestas B, McClorey G, Tedebark U, Moreno PMD, Roberts TC, Hammond SM, Smith CIE, Wood MJA, Andaloussi SE. Design and application of bispecific splice-switching oligonucleotides. Nucleic Acid Ther 2014; 24:13-24. [PMID: 24506779 DOI: 10.1089/nat.2013.0462] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Targeting of pre-mRNA by short splice-switching oligonucleotides (SSOs) is increasingly being used as a therapeutic modality, one rationale being to disrupt splicing so as to remove exons containing premature termination codons, or to restore the translation reading frame around out-of-frame deletion mutations. The aim of this study was to investigate the effect of chemically linking individual SSOs so as to ascertain equimolar cellular uptake that would provide for more defined drug formulations. In contrast to conventional bispecific SSOs generated by conjugation in solution, here we describe a protocol for synthesis of bispecific SSOs on solid phase. These SSOs comprised of either a non-cleavable hydrocarbon linker or disulfide-based cleavable linkers. To assess the efficacy of these SSOs we have utilized splice switching to bypass a disease-causing mutation in the DMD gene concurrent with disruption of the reading frame of the myostatin gene (Mstn). The premise of this approach is that disruption of myostatin expression is known to induce muscle hypertrophy and so for Duchenne muscular dystrophy (DMD) could be expected to have a better outcome than dystrophin restoration alone. All tested SSOs mediated simultaneous robust exon removal from mature Dmd and Mstn transcripts in myotubes. Our results also demonstrate that using cleavable SSOs is preferred over the non-cleavable counterparts and that these are equally efficient at inducing exon skipping as cocktails of monospecific versions. In conclusion, we have developed a protocol for solid-phase synthesis of single molecule cleavable bispecific SSOs that can be efficiently exploited for targeting of multiple RNA transcripts.
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Affiliation(s)
- Burcu Bestas
- 1 Department of Laboratory Medicine, Karolinska Institutet , Huddinge, Sweden
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61
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Huynh T, Uaesoontrachoon K, Quinn JL, Tatem KS, Heier CR, Van Der Meulen JH, Yu Q, Harris M, Nolan CJ, Haegeman G, Grounds MD, Nagaraju K. Selective modulation through the glucocorticoid receptor ameliorates muscle pathology in mdx mice. J Pathol 2013; 231:223-35. [PMID: 23794417 DOI: 10.1002/path.4231] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Revised: 05/11/2013] [Accepted: 06/01/2013] [Indexed: 02/05/2023]
Abstract
The over-expression of NF-κB signalling in both muscle and immune cells contribute to the pathology in dystrophic muscle. The anti-inflammatory properties of glucocorticoids, mediated predominantly through monomeric glucocorticoid receptor inhibition of transcription factors such as NF-κB (transrepression), are postulated to be an important mechanism for their beneficial effects in Duchenne muscular dystrophy. Chronic glucocorticoid therapy is associated with adverse effects on metabolism, growth, bone mineral density and the maintenance of muscle mass. These detrimental effects result from direct glucocorticoid receptor homodimer interactions with glucocorticoid response elements of the relevant genes. Compound A, a non-steroidal selective glucocorticoid receptor modulator, is capable of transrepression without transactivation. We confirm the in vitro NF-κB inhibitory activity of compound A in H-2K(b) -tsA58 mdx myoblasts and myotubes, and demonstrate improvements in disease phenotype of dystrophin deficient mdx mice. Compound A treatment in mdx mice from 18 days of post-natal age to 8 weeks of age increased the absolute and normalized forelimb and hindlimb grip strength, attenuated cathepsin-B enzyme activity (a surrogate marker for inflammation) in forelimb and hindlimb muscles, decreased serum creatine kinase levels and reduced IL-6, CCL2, IFNγ, TNF and IL-12p70 cytokine levels in gastrocnemius (GA) muscles. Compared with compound A, treatment with prednisolone, a classical glucocorticoid, in both wild-type and mdx mice was associated with reduced body weight, reduced GA, tibialis anterior and extensor digitorum longus muscle mass and shorter tibial lengths. Prednisolone increased osteopontin (Spp1) gene expression and osteopontin protein levels in the GA muscles of mdx mice and had less favourable effects on the expression of Foxo1, Foxo3, Fbxo32, Trim63, Mstn and Igf1 in GA muscles, as well as hepatic Igf1 in wild-type mice. In conclusion, selective glucocorticoid receptor modulation by compound A represents a potential therapeutic strategy to improve dystrophic pathology.
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Affiliation(s)
- Tony Huynh
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC, USA; Endocrine Research Unit and the Australian National University Medical School, Canberra Hospital, ACT, Australia
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62
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Eulitz S, Sauer F, Pelissier MC, Boisguerin P, Molt S, Schuld J, Orfanos Z, Kley RA, Volkmer R, Wilmanns M, Kirfel G, van der Ven PFM, Fürst DO. Identification of Xin-repeat proteins as novel ligands of the SH3 domains of nebulin and nebulette and analysis of their interaction during myofibril formation and remodeling. Mol Biol Cell 2013; 24:3215-26. [PMID: 23985323 PMCID: PMC3810769 DOI: 10.1091/mbc.e13-04-0202] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The striated muscle–specific actin-binding proteins Xin and Xirp2 are identified as novel ligands of the SH3 domains of the thin filament ruler nebulin and nebulette. The interaction is spatially restricted to structures associated with myofibril development or remodeling, indicating a role for these proteins in myofibril assembly and repair. The Xin actin-binding repeat–containing proteins Xin and XIRP2 are exclusively expressed in striated muscle cells, where they are believed to play an important role in development. In adult muscle, both proteins are concentrated at attachment sites of myofibrils to the membrane. In contrast, during development they are localized to immature myofibrils together with their binding partner, filamin C, indicating an involvement of both proteins in myofibril assembly. We identify the SH3 domains of nebulin and nebulette as novel ligands of proline-rich regions of Xin and XIRP2. Precise binding motifs are mapped and shown to bind both SH3 domains with micromolar affinity. Cocrystallization of the nebulette SH3 domain with the interacting XIRP2 peptide PPPTLPKPKLPKH reveals selective interactions that conform to class II SH3 domain–binding peptides. Bimolecular fluorescence complementation experiments in cultured muscle cells indicate a temporally restricted interaction of Xin-repeat proteins with nebulin/nebulette during early stages of myofibril development that is lost upon further maturation. In mature myofibrils, this interaction is limited to longitudinally oriented structures associated with myofibril development and remodeling. These data provide new insights into the role of Xin actin-binding repeat–containing proteins (together with their interaction partners) in myofibril assembly and after muscle damage.
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Affiliation(s)
- Stefan Eulitz
- Institute for Cell Biology, University of Bonn, D-53121 Bonn, Germany European Molecular Biology Laboratory-Hamburg/Deutsches Elektronen-Synchrotron, D-22603 Hamburg, Germany Department of Medicinal Immunology, Charité-University Medicine Berlin, D-13353 Berlin, Germany Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, D-44789 Bochum, Germany
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63
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Duguez S, Duddy W, Johnston H, Lainé J, Le Bihan MC, Brown KJ, Bigot A, Hathout Y, Butler-Browne G, Partridge T. Dystrophin deficiency leads to disturbance of LAMP1-vesicle-associated protein secretion. Cell Mol Life Sci 2013; 70:2159-74. [PMID: 23344255 PMCID: PMC11113779 DOI: 10.1007/s00018-012-1248-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 12/13/2012] [Accepted: 12/17/2012] [Indexed: 01/06/2023]
Abstract
Duchenne muscular dystrophy results from loss of the protein dystrophin, which links the intracellular cytoskeletal network with the extracellular matrix, but deficiency in this function does not fully explain the onset or progression of the disease. While some intracellular events involved in the degeneration of dystrophin-deficient muscle fibers have been well characterized, changes in their secretory profile are undescribed. To analyze the secretome profile of mdx myotubes independently of myonecrosis, we labeled the proteins of mdx and wild-type myotubes with stable isotope-labeled amino acids (SILAC), finding marked enrichment of vesicular markers in the mdx secretome. These included the lysosomal-associated membrane protein, LAMP1, that co-localized in vesicles with an over-secreted cytoskeletal protein, myosin light chain 1. These LAMP1/MLC1-3-positive vesicles accumulated in the cytosol of mdx myotubes and were secreted into the culture medium in a range of abnormal densities. Restitution of dystrophin expression, by exon skipping, to some 30 % of the control value, partially normalized the secretome profile and the excess LAMP1 accumulation. Together, our results suggest that a lack of dystrophin leads to a general dysregulation of vesicle trafficking. We hypothesize that disturbance of the export of proteins through vesicles occurs before, and then concurrently with, the myonecrotic cascade and contributes chronically to the pathophysiology of DMD, thereby presenting us with a range of new potential therapeutic targets.
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Affiliation(s)
- Stephanie Duguez
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
- Institut de Myologie, UM76, Inserm U974, CNRS, UMR7215, Université Pierre et Marie Curie-Paris 6, Paris, 75013 France
| | - William Duddy
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
- Institut de Myologie, UM76, Inserm U974, CNRS, UMR7215, Université Pierre et Marie Curie-Paris 6, Paris, 75013 France
| | - Helen Johnston
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
| | - Jeanne Lainé
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
- Département de Physiologie, Université Pierre Et Marie Curie-Paris 06, Site Pitié-Salpêtrière, Paris, 75013 France
| | - Marie Catherine Le Bihan
- Institut de Myologie, UM76, Inserm U974, CNRS, UMR7215, Université Pierre et Marie Curie-Paris 6, Paris, 75013 France
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Kristy J. Brown
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
| | - Anne Bigot
- Institut de Myologie, UM76, Inserm U974, CNRS, UMR7215, Université Pierre et Marie Curie-Paris 6, Paris, 75013 France
| | - Yetrib Hathout
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
| | - Gillian Butler-Browne
- Institut de Myologie, UM76, Inserm U974, CNRS, UMR7215, Université Pierre et Marie Curie-Paris 6, Paris, 75013 France
| | - Terence Partridge
- Center for Genetic Medicine, Children’s Research Institute, Children’s National Medical Center, 111 Michigan Avenue, Washington, DC USA
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64
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Siegel AL, Gurevich DB, Currie PD. A myogenic precursor cell that could contribute to regeneration in zebrafish and its similarity to the satellite cell. FEBS J 2013; 280:4074-88. [PMID: 23607511 DOI: 10.1111/febs.12300] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 04/12/2013] [Indexed: 11/28/2022]
Abstract
The cellular basis for mammalian muscle regeneration has been an area of intense investigation over recent decades. The consensus is that a specialized self-renewing stem cell, termed the satellite cell, plays a major role during the process of regeneration in amniotes. How broadly this mechanism is deployed within the vertebrate phylogeny remains an open question. A lack of information on the role of cells analogous to the satellite cell in other vertebrate systems is even more unexpected given the fact that satellite cells were first designated in frogs. An intriguing aspect of this debate is that a number of amphibia and many fish species exhibit epimorphic regenerative processes in specific tissues, whereby regeneration occurs by the dedifferentiation of the damaged tissue, without deploying specialized stem cell populations analogous to satellite cells. Hence, it is feasible that a cellular process completely distinct from that deployed during mammalian muscle regeneration could operate in species capable of epimorphic regeneration. In this minireview, we examine the evidence for the broad phylogenetic distribution of satellite cells. We conclude that, in the vertebrates examined so far, epimorphosis does not appear to be deployed during muscle regeneration, and that analogous cells expressing similar marker genes to satellite cells appear to be deployed during the regenerative process. However, the functional definition of these cells as self-renewing muscle stem cells remains a final hurdle to the definition of the satellite cell as a generic vertebrate cell type.
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Affiliation(s)
- Ashley L Siegel
- Australian Regenerative Medicine Institute, Monash University, Clayton, Victoria, Australia.
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65
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Istvanffy R, Oostendorp RAJ. Generation and establishment of murine adherent cell lines. Methods Mol Biol 2013. [PMID: 23179840 DOI: 10.1007/978-1-62703-128-8_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
We describe a method to derive cell lines and clones from cells of the murine midgestation aorta-gonads-mesonephros (AGM) microenvironment. We start from subdissected AGM regions in "explant" or "single cell suspension" type cultures from embryos transgenic for tsA58, a temperature-sensitive mutant of the SV40 T antigen gene. The number of cells in such cultures initially expand, but in most cases, this expansion phase is followed by a stable or even decline in cell number. After this so-called crisis phase, cell proliferation is noticeable in more than 90% of the cultures. Stromal cell clones can be isolated from these cultures, some of which have been cultured for more than 50 population doublings, and functionally characterized using various methods These stromal cell clones are valuable tools for the study of the regulation of hematopoietic stem and progenitor cells in the midgestation mouse embryo.
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Affiliation(s)
- Rouzanna Istvanffy
- The Stem Cell Physiology Laboratory, Medizinische Klinik, Technische Universität München, Munich, Germany
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66
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Yang L, Niu H, Gao X, Wang Q, Han G, Cao L, Cai C, Weiler J, Yin H. Effective exon skipping and dystrophin restoration by 2'-o-methoxyethyl antisense oligonucleotide in dystrophin-deficient mice. PLoS One 2013; 8:e61584. [PMID: 23658612 PMCID: PMC3637291 DOI: 10.1371/journal.pone.0061584] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Accepted: 03/11/2013] [Indexed: 01/30/2023] Open
Abstract
Antisense oligonucleotide (AO)–mediated exon-skipping therapy is one of the most promising therapeutic strategies for Duchenne Muscular Dystrophy (DMD) and several AO chemistries have been rigorously investigated. In this report, we focused on the effect of 2′-O-methoxyethyl oligonucleotides (MOE) on exon skipping in cultured mdx myoblasts and mice. Efficient dose-dependent skipping of targeted exon 23 was achieved in myoblasts with MOE AOs of different lengths and backbone chemistries. Furthermore, we established that 25-mer MOE phosphorothioate (PS) AOs provided the greatest exon-skipping efficacy. When compared with 2′O methyl phosphorothioate (2′OmePS) AOs, 25-mer MOE (PS) AOs also showed higher exon-skipping activity in vitro and in mdx mice after intramuscular injections. Characterization of uptake in vitro corroborated with exon-skipping results, suggesting that increased uptake of 25-mer MOE PS AOs might partly contribute to the difference in exon-skipping activity observed in vitro and in mdx mice. Our findings demonstrate the substantial potential for MOE PS AOs as an alternative option for the treatment of DMD.
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MESH Headings
- Animals
- Disease Models, Animal
- Dystrophin/genetics
- Dystrophin/metabolism
- Exons
- Genetic Therapy
- Humans
- Injections, Intramuscular
- Mice
- Mice, Transgenic
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Muscular Dystrophy, Duchenne/therapy
- Myoblasts/drug effects
- Myoblasts/metabolism
- Myoblasts/pathology
- Oligonucleotides, Antisense/genetics
- Oligonucleotides, Antisense/pharmacology
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Affiliation(s)
- Lu Yang
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Hongjing Niu
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Xianjun Gao
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Qingsong Wang
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Gang Han
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Limin Cao
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Chunquan Cai
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
| | - Jan Weiler
- Novartis Institutes for BioMedical Research Inc., NIBR Biologics Center, Cambridge, Massachusetts, United States of America
| | - Haifang Yin
- Research Centre of Basic Medical Science, Tianjin Medical University, Heping District, Tianjin, China
- * E-mail:
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67
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Cohen TV, Gnocchi VF, Cohen JE, Phadke A, Liu H, Ellis JA, Foisner R, Stewart CL, Zammit PS, Partridge TA. Defective skeletal muscle growth in lamin A/C-deficient mice is rescued by loss of Lap2α. Hum Mol Genet 2013; 22:2852-69. [PMID: 23535822 DOI: 10.1093/hmg/ddt135] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mutations in lamin A/C result in a range of tissue-specific disorders collectively called laminopathies. Of these, Emery-Dreifuss and Limb-Girdle muscular dystrophy 1B mainly affect striated muscle. A useful model for understanding both laminopathies and lamin A/C function is the Lmna(-/-) mouse. We found that skeletal muscle growth and muscle satellite (stem) cell proliferation were both reduced in Lmna(-/-) mice. Lamins A and C associate with lamina-associated polypeptide 2 alpha (Lap2α) and the retinoblastoma gene product, pRb, to regulate cell cycle exit. We found Lap2α to be upregulated in Lmna(-/-) myoblasts (MBs). To specifically test the contribution of elevated Lap2α to the phenotype of Lmna(-/-) mice, we generated Lmna(-/-)Lap2α(-/-) mice. Lifespan and body mass were increased in Lmna(-/-)Lap2α(-/-) mice compared with Lmna(-/-). Importantly, the satellite cell proliferation defect was rescued, resulting in improved myogenesis. Lmna(-/-) MBs also exhibited increased levels of Smad2/3, which were abnormally distributed in the cell and failed to respond to TGFβ1 stimulation as in control cells. However, using SIS3 to inhibit signaling via Smad3 reduced cell death and augmented MB fusion. Together, our results show that perturbed Lap2α/pRb and Smad2/3 signaling are important regulatory pathways mediating defective muscle growth in Lmna(-/-) mice, and that inhibition of either pathway alone or in combination can ameliorate this deleterious phenotype.
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Affiliation(s)
- Tatiana V Cohen
- Research Center for Genetic Medicine, Children’s National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA.
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68
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Zhou W, He DQ, Liu JY, Feng Y, Zhang XY, Hua CG, Tang XF. Angiogenic gene-modified myoblasts promote vascularization during repair of skeletal muscle defects. J Tissue Eng Regen Med 2013; 9:1404-16. [PMID: 23365046 DOI: 10.1002/term.1692] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2012] [Revised: 10/20/2012] [Accepted: 12/20/2012] [Indexed: 02/05/2023]
Affiliation(s)
- Wei Zhou
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Deng-Qi He
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Ji-Yuan Liu
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Yang Feng
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Xiang-Yu Zhang
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Cheng-Ge Hua
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Xiu-Fa Tang
- Department of Head and Neck Oncology; State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
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69
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Duguez S, Duddy WJ, Gnocchi V, Bowe J, Dadgar S, Partridge TA. Atmospheric oxygen tension slows myoblast proliferation via mitochondrial activation. PLoS One 2012; 7:e43853. [PMID: 22937109 PMCID: PMC3427224 DOI: 10.1371/journal.pone.0043853] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2011] [Accepted: 07/30/2012] [Indexed: 11/23/2022] Open
Abstract
Background Mitochondrial activity inhibits proliferation and is required for differentiation of myoblasts. Myoblast proliferation is also inhibited by the ∼20% oxygen level used in standard tissue culture. We hypothesize that mitochondrial activity would be greater at hyperoxia (20% O2) relative to more physiological oxygen (5% O2). Methodology/Principal Findings Murine primary myoblasts from isolated myofibres and conditionally immortalized H-2K myoblasts were cultured at 5% and 20% oxygen. Proliferation, assayed by cell counts, EdU labeling, and CFSE dilution, was slower at 20% oxygen. Expression of MyoD in primary myoblasts was delayed at 20% oxygen, but myogenicity, as measured by fusion index, was slightly higher. FACS-based measurement of mitochondrial activity indicators and luminometric measurement of ATP levels revealed that mitochondria exhibited greater membrane potential and higher levels of Reactive Oxygen Species (ROS) at 20% oxygen with concomitant elevation of intracellular ATP. Mitochondrial mass was unaffected. Low concentrations of CCCP, a respiratory chain uncoupler, and Oligomycin A, an ATP synthase inhibitor, each increased the rate of myoblast proliferation. ROS were investigated as a potential mechanism of mitochondrial retrograde signaling, but scavenging of ROS levels by N-acetyl-cysteine (NAC) or α-Phenyl-N-tert-butylnitrone (PBN) did not rescue the suppressed rate of cell division in hyperoxic conditions, suggesting other pathways. Primary myoblasts from older mice showed a slower proliferation than those from younger adult mice at 20% oxygen but no difference at 5% oxygen. Conclusions/Significance These results implicate mitochondrial regulation as a mechanistic explanation for myoblast response to oxygen tension. The rescue of proliferation rate in myoblasts of aged mice by 5% oxygen suggests a major artefactual component to age-related decline of satellite cell proliferation in standard tissue culture at 20% oxygen. It lends weight to the idea that these age-related changes result at least in part from environmental factors rather than characteristics intrinsic to the satellite cell.
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Affiliation(s)
- Stephanie Duguez
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
- Université Pierre et Marie Curie (UPMC UMR S 974)-Institut National de la Santé et de la Recherche Médicale (Inserm U974)-Centre National de la Recherche Scientifique (CNRS UMR 7215), Institut de Myologie, Paris, France
| | - William J. Duddy
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
- Université Pierre et Marie Curie (UPMC UMR S 974)-Institut National de la Santé et de la Recherche Médicale (Inserm U974)-Centre National de la Recherche Scientifique (CNRS UMR 7215), Institut de Myologie, Paris, France
- * E-mail:
| | - Viola Gnocchi
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
| | - James Bowe
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
| | - Sherry Dadgar
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
| | - Terence A. Partridge
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, District of Columbia, United States of America
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70
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Bodywide skipping of exons 45-55 in dystrophic mdx52 mice by systemic antisense delivery. Proc Natl Acad Sci U S A 2012; 109:13763-8. [PMID: 22869723 DOI: 10.1073/pnas.1204638109] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD), the commonest form of muscular dystrophy, is caused by lack of dystrophin. One of the most promising therapeutic approaches is antisense-mediated elimination of frame-disrupting mutations by exon skipping. However, this approach faces two major hurdles: limited applicability of each individual target exon and uncertain function and stability of each resulting truncated dystrophin. Skipping of exons 45-55 at the mutation hotspot of the DMD gene would address both issues. Theoretically it could rescue more than 60% of patients with deletion mutations. Moreover, spontaneous deletions of this specific region are associated with asymptomatic or exceptionally mild phenotypes. However, such multiple exon skipping of exons 45-55 has proved technically challenging. We have therefore designed antisense oligo (AO) morpholino mixtures to minimize self- or heteroduplex formation. These were tested as conjugates with cell-penetrating moieties (vivo-morpholinos). We have tested the feasibility of skipping exons 45-55 in H2K-mdx52 myotubes and in mdx52 mice, which lack exon 52. Encouragingly, with mixtures of 10 AOs, we demonstrated skipping of all 10 exons in vitro, in H2K-mdx52 myotubes and on intramuscular injection into mdx52 mice. Moreover, in mdx52 mice in vivo, systemic injections of 10 AOs induced extensive dystrophin expression at the subsarcolemma in skeletal muscles throughout the body, producing up to 15% of wild-type dystrophin protein levels, accompanied by improved muscle strength and histopathology without any detectable toxicity. This is a unique successful demonstration of effective rescue by exon 45-55 skipping in a dystrophin-deficient animal model.
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71
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Miller G, Moore CJ, Terry R, La Riviere T, Mitchell A, Piggott R, Dear TN, Wells DJ, Winder SJ. Preventing phosphorylation of dystroglycan ameliorates the dystrophic phenotype in mdx mouse. Hum Mol Genet 2012; 21:4508-20. [PMID: 22810924 DOI: 10.1093/hmg/dds293] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Loss of dystrophin protein due to mutations in the DMD gene causes Duchenne muscular dystrophy. Dystrophin loss also leads to the loss of the dystrophin glycoprotein complex (DGC) from the sarcolemma which contributes to the dystrophic phenotype. Tyrosine phosphorylation of dystroglycan has been identified as a possible signal to promote the proteasomal degradation of the DGC. In order to test the role of tyrosine phosphorylation of dystroglycan in the aetiology of DMD, we generated a knock-in mouse with a phenylalanine substitution at a key tyrosine phosphorylation site in dystroglycan, Y890. Dystroglycan knock-in mice (Dag1(Y890F/Y890F)) had no overt phenotype. In order to examine the consequence of blocking dystroglycan phosphorylation on the aetiology of dystrophin-deficient muscular dystrophy, the Y890F mice were crossed with mdx mice an established model of muscular dystrophy. Dag1(Y890F/Y890F)/mdx mice showed a significant improvement in several parameters of muscle pathophysiology associated with muscular dystrophy, including a reduction in centrally nucleated fibres, less Evans blue dye infiltration and lower serum creatine kinase levels. With the exception of dystrophin, other DGC components were restored to the sarcolemma including α-sarcoglycan, α-/β-dystroglycan and sarcospan. Furthermore, Dag1(Y890F/Y890F)/mdx showed a significant resistance to muscle damage and force loss following repeated eccentric contractions when compared with mdx mice. While the Y890F substitution may prevent dystroglycan from proteasomal degradation, an increase in sarcolemmal plectin appeared to confer protection on Dag1(Y890F/Y890F)/mdx mouse muscle. This new model confirms dystroglycan phosphorylation as an important pathway in the aetiology of DMD and provides novel targets for therapeutic intervention.
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Affiliation(s)
- Gaynor Miller
- Department of Cardiovascular Science, University of Sheffield, Firth Court, Western Bank, Sheffield, S10 2TN, UK
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72
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Sharma N, Medikayala S, Defour A, Rayavarapu S, Brown KJ, Hathout Y, Jaiswal JK. Use of quantitative membrane proteomics identifies a novel role of mitochondria in healing injured muscles. J Biol Chem 2012; 287:30455-67. [PMID: 22778268 DOI: 10.1074/jbc.m112.354415] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Skeletal muscles are proficient at healing from a variety of injuries. Healing occurs in two phases, early and late phase. Early phase involves healing the injured sarcolemma and restricting the spread of damage to the injured myofiber. Late phase of healing occurs a few days postinjury and involves interaction of injured myofibers with regenerative and inflammatory cells. Of the two phases, cellular and molecular processes involved in the early phase of healing are poorly understood. We have implemented an improved sarcolemmal proteomics approach together with in vivo labeling of proteins with modified amino acids in mice to study acute changes in the sarcolemmal proteome in early phase of myofiber injury. We find that a notable early phase response to muscle injury is an increased association of mitochondria with the injured sarcolemma. Real-time imaging of live myofibers during injury demonstrated that the increased association of mitochondria with the injured sarcolemma involves translocation of mitochondria to the site of injury, a response that is lacking in cultured myoblasts. Inhibiting mitochondrial function at the time of injury inhibited healing of the injured myofibers. This identifies a novel role of mitochondria in the early phase of healing injured myofibers.
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Affiliation(s)
- Nimisha Sharma
- Center for Genetic Medicine Research, Children's National Medical Center, Washington, DC 20010, USA
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73
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Baudy AR, Reeves EKM, Damsker JM, Heier C, Garvin LM, Dillingham BC, McCall J, Rayavarapu S, Wang Z, Vandermeulen JH, Sali A, Jahnke V, Duguez S, DuBois D, Rose MC, Nagaraju K, Hoffman EP. Δ-9,11 modification of glucocorticoids dissociates nuclear factor-κB inhibitory efficacy from glucocorticoid response element-associated side effects. J Pharmacol Exp Ther 2012; 343:225-32. [PMID: 22743576 DOI: 10.1124/jpet.112.194340] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Glucocorticoids are standard of care for many inflammatory conditions, but chronic use is associated with a broad array of side effects. This has led to a search for dissociative glucocorticoids--drugs able to retain or improve efficacy associated with transrepression [nuclear factor-κB (NF-κB) inhibition] but with the loss of side effects associated with transactivation (receptor-mediated transcriptional activation through glucocorticoid response element gene promoter elements). We investigated a glucocorticoid derivative with a Δ-9,11 modification as a dissociative steroid. The Δ-9,11 analog showed potent inhibition of tumor necrosis factor-α-induced NF-κB signaling in cell reporter assays, and this transrepression activity was blocked by 17β-hydroxy-11β-[4-dimethylamino phenyl]-17α-[1-propynyl]estra-4,9-dien-3-one (RU-486), showing the requirement for the glucocorticoid receptor (GR). The Δ-9,11 analog induced the nuclear translocation of GR but showed the loss of transactivation as assayed by GR-luciferase constructs as well as mRNA profiles of treated cells. The Δ-9,11 analog was tested for efficacy and side effects in two mouse models of muscular dystrophy: mdx (dystrophin deficiency), and SJL (dysferlin deficiency). Daily oral delivery of the Δ-9,11 analog showed a reduction of muscle inflammation and improvements in multiple muscle function assays yet no reductions in body weight or spleen size, suggesting the loss of key side effects. Our data demonstrate that a Δ-9,11 analog dissociates the GR-mediated transcriptional activities from anti-inflammatory activities. Accordingly, Δ-9,11 analogs may hold promise as a source of safer therapeutic agents for chronic inflammatory disorders.
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Affiliation(s)
- Andreas R Baudy
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, District of Columbia, USA
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Abstract
Myostatin (Mstn) is a secreted growth factor that negatively regulates muscle mass and is therefore a potential pharmacological target for the treatment of muscle wasting disorders such as Duchenne muscular dystrophy. Here we describe a novel Mstn blockade approach in which small interfering RNAs (siRNAs) complementary to a promoter-associated transcript induce transcriptional gene silencing (TGS) in two differentiated mouse muscle cell lines. Silencing is sensitive to treatment with the histone deacetylase inhibitor trichostatin A, and the silent state chromatin mark H3K9me2 is enriched at the Mstn promoter following siRNA transfection, suggesting epigenetic remodeling underlies the silencing effect. These observations suggest that long-term epigenetic silencing may be feasible for Mstn and that TGS is a promising novel therapeutic strategy for the treatment of muscle wasting disorders.
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75
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Koch AJ, Holaska JM. Loss of emerin alters myogenic signaling and miRNA expression in mouse myogenic progenitors. PLoS One 2012; 7:e37262. [PMID: 22606356 PMCID: PMC3350500 DOI: 10.1371/journal.pone.0037262] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 04/19/2012] [Indexed: 01/01/2023] Open
Abstract
Emerin is an integral membrane protein of the inner nuclear membrane. Mutations in emerin cause X-linked Emery-Dreifuss muscular dystrophy (EDMD), a disease characterized by skeletal muscle wasting and dilated cardiomyopathy. Current evidence suggests the muscle wasting phenotype of EDMD is caused by defective myogenic progenitor cell differentiation and impaired muscle regeneration. We obtained genome-wide expression data for both mRNA and micro-RNA (miRNA) in wildtype and emerin-null mouse myogenic progenitor cells. We report here that emerin-null myogenic progenitors exhibit differential expression of multiple signaling pathway components required for normal muscle development and regeneration. Components of the Wnt, IGF-1, TGF-β, and Notch signaling pathways are misexpressed in emerin-null myogenic progenitors at both the mRNA and protein levels. We also report significant perturbations in the expression and activation of p38/Mapk14 in emerin-null myogenic progenitors, showing that perturbed expression of Wnt, IGF-1, TGF-β, and Notch signaling components disrupts normal downstream myogenic signaling in these cells. Collectively, these data support the hypothesis that emerin is essential for proper myogenic signaling in myogenic progenitors, which is necessary for myogenic differentiation and muscle regeneration.
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Affiliation(s)
- Adam J. Koch
- The University of Chicago Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, Illinois, United States of America
| | - James M. Holaska
- The University of Chicago Committee on Genetics, Genomics and Systems Biology, The University of Chicago, Chicago, Illinois, United States of America
- Department of Medicine, Section of Cardiology, The University of Chicago, Chicago, Illinois, United States of America
- Committee on Developmental, Regeneration and Stem Cell Biology, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Cohen TV, Cohen JE, Partridge TA. Myogenesis in dysferlin-deficient myoblasts is inhibited by an intrinsic inflammatory response. Neuromuscul Disord 2012; 22:648-58. [PMID: 22560623 DOI: 10.1016/j.nmd.2012.03.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 02/20/2012] [Accepted: 03/02/2012] [Indexed: 01/13/2023]
Abstract
Limb-girdle muscular dystrophy type 2B results from mutations in dysferlin, a membrane-associated protein involved in cellular membrane repair. Primary myoblast cultures derived from dysferlinopathy patients show reduced myogenic potential, suggesting that dysferlin may regulate myotube fusion and be required for muscle regeneration. These observations contrast with the findings that muscle develops normally in pre-symptomatic dysferlinopathy patients. To better understand the role of dysferlin in myogenesis, we investigated this process in vitro using cells derived from two mouse models of dysferlinopathy: SJL/J and A/J mice. We observed that myotubes derived from dysferlin-deficient muscle were of significantly smaller diameters, contained fewer myonuclei, and displayed reduced myogenic gene expression compared to dysferlin-sufficient cells. Together, these findings suggest that the absence of dysferlin from myoblasts is detrimental to myogenesis. Pro-inflammatory NFκB signaling was upregulated in dysferlin-deficient myotubes; the anti-inflammatory agent celastrol reduced the NFκB activation and improved myogenesis in dysferlin-deficient cultures. The results suggest that decreased myotube fusion in dysferlin deficiency is attributable to intrinsic inflammatory activation and can be improved using anti-inflammatory mediators.
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Affiliation(s)
- Tatiana V Cohen
- Research Center for Genetic Medicine, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC 20010, USA
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77
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Abstract
The receptor tyrosine kinase MuSK is indispensable for nerve-muscle synapse formation and maintenance. MuSK is necessary for prepatterning of the endplate zone anlage and as a signaling receptor for agrin-mediated postsynaptic differentiation. MuSK-associated proteins such as Dok7, LRP4, and Wnt11r are involved in these early events in neuromuscular junction formation. However, the mechanisms regulating synapse stability are poorly understood. Here we examine a novel role for the extracellular matrix protein biglycan in synapse stability. Synaptic development in fetal and early postnatal biglycan null (bgn(-/o)) muscle is indistinguishable from wild-type controls. However, by 5 weeks after birth, nerve-muscle synapses in bgn(-/o) mice are abnormal as judged by the presence of perijunctional folds, increased segmentation, and focal misalignment of acetylcholinesterase and AChRs. These observations indicate that previously occupied presynaptic and postsynaptic territory has been vacated. Biglycan binds MuSK and the levels of this receptor tyrosine kinase are selectively reduced at bgn(-/o) synapses. In bgn(-/o) myotubes, the initial stages of agrin-induced MuSK phosphorylation and AChR clustering are normal, but the AChR clusters are unstable. This stability defect can be substantially rescued by the addition of purified biglycan. Together, these results indicate that biglycan is an extracellular ligand for MuSK that is important for synapse stability.
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78
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Botezatu L, Sievers S, Gama-Norton L, Schucht R, Hauser H, Wirth D. Genetic aspects of cell line development from a synthetic biology perspective. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2012; 127:251-284. [PMID: 22068842 DOI: 10.1007/10_2011_117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Animal cells can be regarded as factories for the production of relevant proteins. The advances described in this chapter towards the development of cell lines with higher productivity capacities, certain metabolic and proliferation properties, reduced apoptosis and other features must be regarded in an integrative perspective. The systematic application of systems biology approaches in combination with a synthetic arsenal for targeted modification of endogenous networks are proposed to lead towards the achievement of a predictable and technologically advanced cell system with high biotechnological impact.
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Affiliation(s)
- L Botezatu
- Helmholtz Centre for Infection Research, Braunschweig, Germany
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79
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Restoration of dystrophin expression using the Sleeping Beauty transposon. PLOS CURRENTS 2011; 3:RRN1296. [PMID: 22318674 PMCID: PMC3269885 DOI: 10.1371/currents.rrn1296] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/29/2011] [Indexed: 11/25/2022]
Abstract
The Sleeping beauty (SB) system is a non-viral DNA based vector that has been used to stably integrate therapeutic genes into disease models. Here we report the SB system is capable of stably integrating the ΔR4-R23/CTΔ micro-dystrophin gene into a conditionally immortal dystrophin deficient muscle cell-line, H2K SF1, a murine cell model for Duchenne muscular dystrophy. Genetically corrected H2K SF1 cells retained their myogenic properties in vitro. Moreover, upon transplantation ΔR4-R23/CTΔ micro-dystrophin expression was detected within mdx nu/nu mice. Our data suggests the SB system is an effective way of stably integrating therapeutic genes into myogenic cells.
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80
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Perez-Pinera P, Ousterout DG, Brown MT, Gersbach CA. Gene targeting to the ROSA26 locus directed by engineered zinc finger nucleases. Nucleic Acids Res 2011; 40:3741-52. [PMID: 22169954 PMCID: PMC3333879 DOI: 10.1093/nar/gkr1214] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Targeted gene addition to mammalian genomes is central to biotechnology, basic research and gene therapy. For example, gene targeting to the ROSA26 locus by homologous recombination in embryonic stem cells is commonly used for mouse transgenesis to achieve ubiquitous and persistent transgene expression. However, conventional methods are not readily adaptable to gene targeting in other cell types. The emerging zinc finger nuclease (ZFN) technology facilitates gene targeting in diverse species and cell types, but an optimal strategy for engineering highly active ZFNs is still unclear. We used a modular assembly approach to build ZFNs that target the ROSA26 locus. ZFN activity was dependent on the number of modules in each zinc finger array. The ZFNs were active in a variety of cell types in a time- and dose-dependent manner. The ZFNs directed gene addition to the ROSA26 locus, which enhanced the level of sustained gene expression, the uniformity of gene expression within clonal cell populations and the reproducibility of gene expression between clones. These ZFNs are a promising resource for cell engineering, mouse transgenesis and pre-clinical gene therapy studies. Furthermore, this characterization of the modular assembly method provides general insights into the implementation of the ZFN technology.
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Affiliation(s)
- Pablo Perez-Pinera
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
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81
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A new extensively characterised conditionally immortal muscle cell-line for investigating therapeutic strategies in muscular dystrophies. PLoS One 2011; 6:e24826. [PMID: 21935475 PMCID: PMC3173493 DOI: 10.1371/journal.pone.0024826] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Accepted: 08/18/2011] [Indexed: 01/13/2023] Open
Abstract
A new conditionally immortal satellite cell-derived cell-line, H2K 2B4, was generated from the H2Kb-tsA58 immortomouse. Under permissive conditions H2K 2B4 cells terminally differentiate in vitro to form uniform myotubes with a myogenic protein profile comparable with freshly isolated satellite cells. Following engraftment into immunodeficient dystrophin-deficient mice, H2K 2B4 cells regenerated host muscle with donor derived myofibres that persisted for at least 24 weeks, without forming tumours. These cells were readily transfectable using both retrovirus and the non-viral transfection methods and importantly upon transplantation, were able to reconstitute the satellite cell niche with functional donor derived satellite cells. Finally using the Class II DNA transposon, Sleeping Beauty, we successfully integrated a reporter plasmid into the genome of H2K 2B4 cells without hindering the myogenic differentiation. Overall, these data suggest that H2K 2B4 cells represent a readily transfectable stable cell-line in which to investigate future stem cell based therapies for muscle disease.
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82
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Modeling oculopharyngeal muscular dystrophy in myotube cultures reveals reduced accumulation of soluble mutant PABPN1 protein. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:1988-2000. [PMID: 21854744 DOI: 10.1016/j.ajpath.2011.06.044] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2011] [Revised: 06/07/2011] [Accepted: 06/21/2011] [Indexed: 12/17/2022]
Abstract
Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant disease caused by an alanine tract expansion mutation in poly(A) binding protein nuclear 1 (expPABPN1). To model OPMD in a myogenic and physiological context, we generated mouse myoblast cell clones stably expressing either human wild type (WT) or expPABPN1 at low levels. Transgene expression is induced on myotube differentiation and results in formation of insoluble nuclear PABPN1 aggregates that are similar to those observed in patients with OPMD. Quantitative analysis of PABPN1 in myotube cultures revealed that expPABPN1 accumulation and aggregation is greater than that of the WT protein. We found that aggregation of expPABPN1 is more affected than WT PABPN1 by inhibition of proteasome activity. Consistent with this, in myotube cultures expressing expPABPN1, deregulation of the proteasome was identified as the most significantly perturbed pathway. Differences in the accumulation of soluble WT and expPABPN1 were consistent with differences in ubiquitination and rate of protein turnover. This study demonstrates, for the first time to our knowledge, that, in myotubes, the ratio of soluble/insoluble expPABPN1 is significantly lower compared with that of the WT protein. We suggest that this difference can contribute to muscle weakness in OPMD.
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83
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Abstract
Duchenne muscular dystrophy is a devastating muscular dystrophy of childhood. Mutations in the dystrophin gene destroy the link between the internal muscle filaments and the extracellular matrix, resulting in severe muscle weakness and progressive muscle wasting. There is currently no cure and, whilst palliative treatment has improved, affected boys are normally confined to a wheelchair by 12 years of age and die from respiratory or cardiac complications in their twenties or thirties. Therapies currently being developed include mutation-specific treatments, DNA- and cell-based therapies, and drugs which aim to modulate cellular pathways or gene expression. This review aims to provide an overview of the different therapeutic approaches aimed at reconstructing the dystrophin-associated protein complex, including restoration of dystrophin expression and upregulation of the functional homologue, utrophin.
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Affiliation(s)
- Rebecca J Fairclough
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford UK
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84
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Dore-Duffy P, Mehedi A, Wang X, Bradley M, Trotter R, Gow A. Immortalized CNS pericytes are quiescent smooth muscle actin-negative and pluripotent. Microvasc Res 2011; 82:18-27. [PMID: 21515289 PMCID: PMC3250068 DOI: 10.1016/j.mvr.2011.04.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 04/05/2011] [Accepted: 04/09/2011] [Indexed: 01/31/2023]
Abstract
Despite their identification more than 100 years ago by the French scientist Charles-Marie Benjamin Rouget, microvascular pericytes have proven difficult to functionally characterize, due in part to their relatively low numbers and the lack of specific cell markers. However, recent progress is beginning to shed light on the diverse biological functions of these cells. Pericytes are thought to be involved in regulating vascular homeostasis and hemostasis as well as serving as a local source of adult stem cells. To further define the properties of these intriguing cells, we have isolated pericytes from transgenic mice (Immortomouse®) harboring a temperature-sensitive mutant of the SV40 virus target T-gene. This Immortopericyte (IMP) conditional cell line is stable for long periods of time and, at 33°C in the presence of interferon gamma, does not differentiate. Under these conditions IMPs are alpha muscle actin-negative and exhibit a pluripotent phenotype, but can be induced to differentiate along both mesenchymal and neuronal lineages at 37°C. Alternatively, differentiation of wild type pericytes and IMPs can be induced directly from capillaries in culture. Finally, the addition of endothelial cells to purified IMP cultures augments their rate of self-renewal and differentiation, possibly in a cell-to-cell contact dependent manner.
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Affiliation(s)
- Paula Dore-Duffy
- Department of Neurology, Division of Neuroimmunology Wayne State University School of Medicine, Detroit, MI 48201, USA.
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85
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Tinsley JM, Fairclough RJ, Storer R, Wilkes FJ, Potter AC, Squire SE, Powell DS, Cozzoli A, Capogrosso RF, Lambert A, Wilson FX, Wren SP, De Luca A, Davies KE. Daily treatment with SMTC1100, a novel small molecule utrophin upregulator, dramatically reduces the dystrophic symptoms in the mdx mouse. PLoS One 2011; 6:e19189. [PMID: 21573153 PMCID: PMC3089598 DOI: 10.1371/journal.pone.0019189] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Accepted: 03/22/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is a lethal, progressive muscle wasting disease caused by a loss of sarcolemmal bound dystrophin, which results in the death of the muscle fibers leading to the gradual depletion of skeletal muscle. There is significant evidence demonstrating that increasing levels of the dystrophin-related protein, utrophin, in mouse models results in sarcolemmal bound utrophin and prevents the muscular dystrophy pathology. The aim of this work was to develop a small molecule which increases the levels of utrophin in muscle and thus has therapeutic potential. METHODOLOGY AND PRINCIPAL FINDINGS We describe the in vivo activity of SMT C1100; the first orally bioavailable small molecule utrophin upregulator. Once-a-day daily-dosing with SMT C1100 reduces a number of the pathological effects of dystrophin deficiency. Treatment results in reduced pathology, better muscle physiology leading to an increase in overall strength, and an ability to resist fatigue after forced exercise; a surrogate for the six minute walk test currently recommended as the pivotal outcome measure in human trials for DMD. CONCLUSIONS AND SIGNIFICANCE This study demonstrates proof-of-principle for the use of in vitro screening methods in allowing identification of pharmacological agents for utrophin transcriptional upregulation. The best compound identified, SMT C1100, demonstrated significant disease modifying effects in DMD models. Our data warrant the full evaluation of this compound in clinical trials in DMD patients.
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Affiliation(s)
| | - Rebecca J. Fairclough
- MRC Functional Genomics Unit, Department of Physiology Anatomy and
Genetics, University of Oxford, Oxford, United Kingdom
| | | | | | - Allyson C. Potter
- MRC Functional Genomics Unit, Department of Physiology Anatomy and
Genetics, University of Oxford, Oxford, United Kingdom
| | - Sarah E. Squire
- MRC Functional Genomics Unit, Department of Physiology Anatomy and
Genetics, University of Oxford, Oxford, United Kingdom
| | - Dave S. Powell
- MRC Functional Genomics Unit, Department of Physiology Anatomy and
Genetics, University of Oxford, Oxford, United Kingdom
| | - Anna Cozzoli
- Unit of Pharmacology, Department of Pharmaco-biology, University of Bari
“A. Moro”, Bari, Italy
| | - Roberta F. Capogrosso
- Unit of Pharmacology, Department of Pharmaco-biology, University of Bari
“A. Moro”, Bari, Italy
| | | | | | | | - Annamaria De Luca
- Unit of Pharmacology, Department of Pharmaco-biology, University of Bari
“A. Moro”, Bari, Italy
| | - Kay E. Davies
- MRC Functional Genomics Unit, Department of Physiology Anatomy and
Genetics, University of Oxford, Oxford, United Kingdom
- * E-mail: (JMT); (KED)
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86
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Ezzat K, Andaloussi SEL, Zaghloul EM, Lehto T, Lindberg S, Moreno PMD, Viola JR, Magdy T, Abdo R, Guterstam P, Sillard R, Hammond SM, Wood MJA, Arzumanov AA, Gait MJ, Smith CIE, Hällbrink M, Langel Ü. PepFect 14, a novel cell-penetrating peptide for oligonucleotide delivery in solution and as solid formulation. Nucleic Acids Res 2011; 39:5284-98. [PMID: 21345932 PMCID: PMC3130259 DOI: 10.1093/nar/gkr072] [Citation(s) in RCA: 163] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Numerous human genetic diseases are caused by mutations that give rise to aberrant alternative splicing. Recently, several of these debilitating disorders have been shown to be amenable for splice-correcting oligonucleotides (SCOs) that modify splicing patterns and restore the phenotype in experimental models. However, translational approaches are required to transform SCOs into usable drug products. In this study, we present a new cell-penetrating peptide, PepFect14 (PF14), which efficiently delivers SCOs to different cell models including HeLa pLuc705 and mdx mouse myotubes; a cell culture model of Duchenne's muscular dystrophy (DMD). Non-covalent PF14-SCO nanocomplexes induce splice-correction at rates higher than the commercially available lipid-based vector Lipofectamine 2000 (LF2000) and remain active in the presence of serum. Furthermore, we demonstrate the feasibility of incorporating this delivery system into solid formulations that could be suitable for several therapeutic applications. Solid dispersion technique is utilized and the formed solid formulations are as active as the freshly prepared nanocomplexes in solution even when stored at an elevated temperatures for several weeks. In contrast, LF2000 drastically loses activity after being subjected to same procedure. This shows that using PF14 is a very promising translational approach for the delivery of SCOs in different pharmaceutical forms.
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Affiliation(s)
- Kariem Ezzat
- Department of Neurochemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
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87
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Abnormal actomyosin assembly in proliferating and differentiating myoblasts upon expression of a cytosolic DMPK isoform. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:867-77. [PMID: 21295081 DOI: 10.1016/j.bbamcr.2011.01.024] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Revised: 01/05/2011] [Accepted: 01/24/2011] [Indexed: 01/17/2023]
Abstract
DMPK, the product of the mutated gene in myotonic dystrophy type 1, belongs to the subfamily of Rho-associated serine-threonine protein kinases, whose members play a role in actin-based cell morphodynamics. Not much is known about the physiological role of differentially localized individual DMPK splice isoforms. We report here that prominent stellar-shaped stress fibers are formed during early and late steps of differentiation in DMPK-deficient myoblast-myotubes upon complementation with the short cytosolic DMPK E isoform. Expression of DMPK E led to an increased phosphorylation status of MLC2. We found no such effects with vectors that encode a mutant DMPK E which was rendered enzymatically inactive or any of the long C-terminally anchored DMPK isoforms. Presence of stellar structures appears associated with changes in cell shape and motility and a delay in myogenesis. Our data strongly suggest that cytosolic DMPK participates in remodeling of the actomyosin cytoskeleton in developing skeletal muscle cells. This article is part of a Special Issue entitled: 11th European Symposium on Calcium.
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88
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Proteomic analysis of the dysferlin protein complex unveils its importance for sarcolemmal maintenance and integrity. PLoS One 2010; 5:e13854. [PMID: 21079765 PMCID: PMC2974636 DOI: 10.1371/journal.pone.0013854] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Accepted: 10/15/2010] [Indexed: 11/19/2022] Open
Abstract
Dysferlin is critical for repair of muscle membranes after damage. Mutations in dysferlin lead to a progressive muscular dystrophy. Recent studies suggest additional roles for dysferlin. We set out to study dysferlin's protein-protein interactions to obtain comprehensive knowledge of dysferlin functionalities in a myogenic context. We developed a robust and reproducible method to isolate dysferlin protein complexes from cells and tissue. We analyzed the composition of these complexes in cultured myoblasts, myotubes and skeletal muscle tissue by mass spectrometry and subsequently inferred potential protein functions through bioinformatics analyses. Our data confirm previously reported interactions and support a function for dysferlin as a vesicle trafficking protein. In addition novel potential functionalities were uncovered, including phagocytosis and focal adhesion. Our data reveal that the dysferlin protein complex has a dynamic composition as a function of myogenic differentiation. We provide additional experimental evidence and show dysferlin localization to, and interaction with the focal adhesion protein vinculin at the sarcolemma. Finally, our studies reveal evidence for cross-talk between dysferlin and its protein family member myoferlin. Together our analyses show that dysferlin is not only a membrane repair protein but also important for muscle membrane maintenance and integrity.
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89
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Abstract
Duchenne muscular dystrophy is mainly caused by mutations that disrupt the generation of a translatable mRNA transcript. Most such mutations occur in parts of the gene that are not essential for its function and thus might be eliminated from the transcript to permit translation of a partially functional protein that would convert the disease to a milder clinical form. Two such antisense oligonucleotides of different backbone chemistries have been successful when tested on the mdx mouse, targeting exon 23, containing the nonsense mutation. Subsequently, the morpholino, the more effective of these, has been tested on the dystrophic dog, where it is necessary to skip 2 exons, again with beneficial results. Currently, results of 2 human trials targeting exon 51 have also yielded promising preliminary results.
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Affiliation(s)
- Terence Partridge
- Genetic Medicine Research Center, Children's National Medical Center, Washington, DC 20010, USA.
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90
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Thompson O, Moore CJ, Hussain SA, Kleino I, Peckham M, Hohenester E, Ayscough KR, Saksela K, Winder SJ. Modulation of cell spreading and cell-substrate adhesion dynamics by dystroglycan. J Cell Sci 2010; 123:118-27. [PMID: 20016072 DOI: 10.1242/jcs.047902] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Dystroglycan is a ubiquitously expressed cell adhesion protein. Its principal role has been determined as a component of the dystrophin-glycoprotein complex of muscle, where it constitutes a key component of the costameric cell adhesion system. To investigate more fundamental aspects of dystroglycan function in cell adhesion, we examined the role of dystroglycan in the dynamics and assembly of cellular adhesions in myoblasts. We show that beta-dystroglycan is recruited to adhesion structures and, based on staining for vinculin, that overexpression or depletion of dystroglycan affects both size and number of fibrillar adhesions. Knockdown of dystroglycan increases the size and number of adhesions, whereas overexpression decreases the number of adhesions. Dystroglycan knockdown or overexpression affects the ability of cells to adhere to different substrates, and has effects on cell migration that are consistent with effects on the formation of fibrillar adhesions. Using an SH3 domain proteomic screen, we identified vinexin as a binding partner for dystroglycan. Furthermore, we show that dystroglycan can interact indirectly with vinculin by binding to the vinculin-binding protein vinexin, and that this interaction has a role in dystroglycan-mediated cell adhesion and spreading. For the first time, we also demonstrate unequivocally that beta-dystroglycan is a resident of focal adhesions.
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Affiliation(s)
- Oliver Thompson
- Departments of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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91
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Peltzer J, Carpentier G, Martelly I, Courty J, Keller A. Transitions towards either slow-oxidative or fast-glycolytic phenotype can be induced in the murine WTt myogenic cell line. J Cell Biochem 2010; 111:82-93. [DOI: 10.1002/jcb.22665] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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92
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Vandenburgh H. High-content drug screening with engineered musculoskeletal tissues. TISSUE ENGINEERING PART B-REVIEWS 2010; 16:55-64. [PMID: 19728786 DOI: 10.1089/ten.teb.2009.0445] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Tissue engineering for in vitro drug-screening applications based on tissue function is an active area of translational research. Compared to targeted high-throughput drug-screening methods that rapidly analyze hundreds of thousands of compounds affecting a single biochemical reaction or gene expression, high-content screening (HCS) with engineered tissues is more complex and based on the cumulative positive and negative effects of a compound on the multiple pathways altering tissue function. It may therefore serve as better predictor of in vivo activity and serve as a bridge between high-throughput drug screening and in vivo animal studies. In the case of the musculoskeletal system, tissue function includes determining improvements in the mechanical properties of bone, tendon, cartilage, and, for skeletal muscle, contractile properties such as rate of contraction/relaxation, force generation, fatigability, and recovery from fatigue. HCS of compound banks with engineered tissues requires miniature musculoskeletal organs as well as automated functional testing. The resulting technologies should be rapid, cost effective, and reduce the number of small animals required for follow-on in vivo studies. Identification of compounds that improve the repair/regeneration of damaged tissues in vivo would have extensive clinical applications for treating musculoskeletal disorders.
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Affiliation(s)
- Herman Vandenburgh
- Department of Pathology, Brown Medical School-Miriam Hospital, Providence, Rhode Island 02906, USA.
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93
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In vivo fluorescence imaging of muscle cell regeneration by transplanted EGFP-labeled myoblasts. Mol Ther 2010; 18:835-42. [PMID: 20125125 DOI: 10.1038/mt.2010.3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
In vivo fluorescence imaging (FLI) enables monitoring fluorescent protein (FP)-labeled cells and proteins in living organisms noninvasively. Here, we examined whether this modality could reach a sufficient sensitivity to allow evaluation of the regeneration process of enhanced green fluorescent protein (eGFP)-labeled muscle precursors (myoblasts). Using a basic FLI station, we were able to detect clear fluorescence signals generated by 40,000 labeled cells injected into a tibialis anterior (TA) muscle of mouse. We observed that the signal declined to approximately 25% on the 48 hours of cell injection followed by a recovery starting at the second day and reached a peak of approximately 45% of the original signal by the 7th day, suggesting that the survived population underwent a limited run of proliferation before differentiation. To assess whether transplanted myoblasts could form satellite cells, we injured the transplanted muscles repeatedly with cardiotoxin. We observed a recovery of fluorescence signal following a disappearance of the signal after each cardiotoxin injection. Histology results showed donor-derived cells located underneath basal membrane and expressing Pax7, confirming that the regeneration observed by imaging was indeed mediated by donor-derived satellite cells. Our results show that FLI is a powerful tool that can extend our ability to unveil complicated biological processes such as stem cell-mediated regeneration.
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94
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O'Leary DA, Sharif O, Anderson P, Tu B, Welch G, Zhou Y, Caldwell JS, Engels IH, Brinker A. Identification of small molecule and genetic modulators of AON-induced dystrophin exon skipping by high-throughput screening. PLoS One 2009; 4:e8348. [PMID: 20020055 PMCID: PMC2791862 DOI: 10.1371/journal.pone.0008348] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 11/23/2009] [Indexed: 11/28/2022] Open
Abstract
One therapeutic approach to Duchenne Muscular Dystrophy (DMD) recently entering clinical trials aims to convert DMD phenotypes to that of a milder disease variant, Becker Muscular Dystrophy (BMD), by employing antisense oligonucleotides (AONs) targeting splice sites, to induce exon skipping and restore partial dystrophin function. In order to search for small molecule and genetic modulators of AON-dependent and independent exon skipping, we screened ∼10,000 known small molecule drugs, >17,000 cDNA clones, and >2,000 kinase- targeted siRNAs against a 5.6 kb luciferase minigene construct, encompassing exon 71 to exon 73 of human dystrophin. As a result, we identified several enhancers of exon skipping, acting on both the reporter construct as well as endogenous dystrophin in mdx cells. Multiple mechanisms of action were identified, including histone deacetylase inhibition, tubulin modulation and pre-mRNA processing. Among others, the nucleolar protein NOL8 and staufen RNA binding protein homolog 2 (Stau2) were found to induce endogenous exon skipping in mdx cells in an AON-dependent fashion. An unexpected but recurrent theme observed in our screening efforts was the apparent link between the inhibition of cell cycle progression and the induction of exon skipping.
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Affiliation(s)
- Debra A. O'Leary
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (DAO); (IHE)
| | - Orzala Sharif
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Paul Anderson
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Buu Tu
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Genevieve Welch
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Yingyao Zhou
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Jeremy S. Caldwell
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
| | - Ingo H. Engels
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
- * E-mail: (DAO); (IHE)
| | - Achim Brinker
- Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America
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95
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Fant X, Srsen V, Espigat-Georger A, Merdes A. Nuclei of non-muscle cells bind centrosome proteins upon fusion with differentiating myoblasts. PLoS One 2009; 4:e8303. [PMID: 20011525 PMCID: PMC2788420 DOI: 10.1371/journal.pone.0008303] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 11/23/2009] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In differentiating myoblasts, the microtubule network is reorganized from a centrosome-bound, radial array into parallel fibres, aligned along the long axis of the cell. Concomitantly, proteins of the centrosome relocalize from the pericentriolar material to the outer surface of the nucleus. The mechanisms that govern this relocalization are largely unknown. METHODOLOGY In this study, we perform experiments in vitro and in cell culture indicating that microtubule nucleation at the centrosome is reduced during myoblast differentiation, while nucleation at the nuclear surface increases. We show in heterologous cell fusion experiments, between cultures of differentiating mouse myoblasts and human cells of non-muscular origin, that nuclei from non-muscle cells recruit centrosome proteins once fused with the differentiating myoblasts. This recruitment still occurs in the presence of cycloheximide and thus appears to be independent of new protein biosynthesis. CONCLUSIONS Altogether, our data suggest that nuclei of undifferentiated cells have the dormant potential to bind centrosome proteins, and that this potential becomes activated during myoblast differentiation.
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Affiliation(s)
- Xavier Fant
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Vlastimil Srsen
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Aude Espigat-Georger
- Unité Mixte de Recherche 2587, Centre National de la Recherche Scientifique-Pierre Fabre, Toulouse, France
| | - Andreas Merdes
- Unité Mixte de Recherche 2587, Centre National de la Recherche Scientifique-Pierre Fabre, Toulouse, France
- * E-mail:
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96
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Oude Ophuis RJA, Mulders SAM, van Herpen REMA, van de Vorstenbosch R, Wieringa B, Wansink DG. DMPK protein isoforms are differentially expressed in myogenic and neural cell lineages. Muscle Nerve 2009; 40:545-55. [PMID: 19626675 DOI: 10.1002/mus.21352] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by an unstable (CTG . CAG)n segment in the 3' untranslated region of the myotonic dystrophy protein kinase (DMPK) gene. It is commonly accepted that DMPK mRNA-based toxicity is the main contributor to DM1 manifestations; however, not much is known about the significance of the DMPK protein. To appreciate its normal and possible pathobiological role, we analyzed the patterns of DMPK splice isoform expression in mouse tissues. Long membrane-anchored DMPK dominated in heart, diaphragm, and skeletal muscle, whereas short cytosolic isoforms were highly expressed in bladder and stomach. Both isoform types were present in diverse brain regions. DMPK protein was also detectable in cultured myoblasts, myotubes, cortical astrocytes, and related cell lines of neural or muscle origin, but not in hippocampal neurons. This work identifies DMPK as a kinase with pronounced expression in diverse muscle and neural tissues that are affected in DM1.
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Affiliation(s)
- Ralph J A Oude Ophuis
- Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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97
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Kesireddy V, van der Ven PFM, Fürst DO. Multipurpose modular lentiviral vectors for RNA interference and transgene expression. Mol Biol Rep 2009; 37:2863-70. [PMID: 19798586 DOI: 10.1007/s11033-009-9840-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2009] [Accepted: 09/15/2009] [Indexed: 11/28/2022]
Abstract
We have created a multipurpose modular lentiviral vector system for expressing both transgenes and miRNA 30-based short hairpins (shRNAmirs) for RNAi. The core of the resulting vector system, pLVmir, allows a simple two step cloning procedure for expressing shRNAmirs under the control of a Pol II promoter in both a constitutive and conditional manner. The adapted cloning method includes a PCR-free method for transferring shRNAmir based RNAi clones from a publicly available library (Open Biosystems). The addition of a Pol II promoter-driven shRNAmir cassette and broadening the choice of Pol III promoters and silencing triggers offers great flexibility to this system. The combination of several preexisting and additional modules created here caters to common needs of researchers. Our modular vector system was validated regarding functionality of promoters, inducibility and reversibility. We successfully applied the system to knockdown Xirp2 mRNA expression in H2kb-tsA58 muscle cells and determined that this had no spurious effect on the expression of a closely related protein. Finally, our set of lentiviral vectors may be used to achieve synergistic effects, for simultaneous knockdown of two genes, as a rescue plasmid and for studying mutant proteins in a physiological context.
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Affiliation(s)
- Venu Kesireddy
- Department of Molecular Cell Biology, Institute for Cell Biology, University of Bonn, Ulrich-Haberland-Str. 61a, 53121 Bonn, Germany
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98
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Fritah A. Control of skeletal muscle metabolic properties by the nuclear receptor corepressor RIP140. Appl Physiol Nutr Metab 2009; 34:362-7. [PMID: 19448699 DOI: 10.1139/h09-026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transcriptional control of metabolism in response to environmental changes plays an important role in energy homeostasis. A number of nuclear receptors control both anabolic and catabolic pathways in metabolic tissues. Their transcriptional activity is mediated by recruitment of coactivators or corepressors to target genes. The corepressor receptor-interacting protein 140 (RIP140) is recruited by many nuclear receptors, including peroxisome proliferator-activated receptors and estrogen-related receptors, and by a number of other transcription factors such as nuclear receptor factor 1. It is responsible for the suppression of gene networks that control catabolism in adipose tissue and skeletal muscle, including glucose uptake, glycolysis, tricarboxylic acid cycle, fatty-acid oxidation, mitochondrial biogenesis, oxidative phosphorylation, and mitochondrial uncoupling. In this review, we focus on the role of RIP140 in regulating energy expenditure and highlight issues to address RIP140 action in skeletal muscle.
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Affiliation(s)
- Asmaà Fritah
- Institute of Reproductive and Developmental Biology, Imperial College London, Faculty of Medicine, Du Cane Road, London W12 0NN, UK
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99
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Onopiuk M, Brutkowski W, Wierzbicka K, Wojciechowska S, Szczepanowska J, Fronk J, Lochmüller H, Górecki DC, Zabłocki K. Mutation in dystrophin-encoding gene affects energy metabolism in mouse myoblasts. Biochem Biophys Res Commun 2009; 386:463-6. [PMID: 19527684 DOI: 10.1016/j.bbrc.2009.06.053] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Accepted: 06/09/2009] [Indexed: 11/28/2022]
Abstract
Duchenne Muscular Dystrophy is characterized by severe defects in differentiated muscle fibers, including abnormal calcium homeostasis and impaired cellular energy metabolism. Here we demonstrate that myoblasts derived from dystrophic (mdx) mouse exhibit reduced oxygen consumption, increased mitochondrial membrane potential, enhanced reactive oxygen species formation, stimulated glycolysis but unaffected total cellular ATP content. Moreover, reduced amounts of specific subunits of the mitochondrial respiratory complexes and ATP-synthase as well as disorganized mitochondrial network were observed. Both the dystrophic and control myoblasts used were derived from a common inbred mouse strain and the only difference between them is a point mutation in the dystrophin-encoding gene, thus these data indicate that this mutation results in multiple phenotypic alterations demonstrating as early as in undifferentiated myoblasts. This finding sheds new light on the molecular mechanisms of Duchenne Muscular Dystrophy pathogenesis.
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Affiliation(s)
- Marta Onopiuk
- Nencki Institute of Experimental Biology, Warsaw, Poland
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100
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Jørgensen LH, Larochelle N, Orlopp K, Dunant P, Dudley RW, Stucka R, Thirion C, Walter MC, Laval SH, Lochmüller H. Efficient and Fast Functional Screening of Microdystrophin ConstructsIn VivoandIn Vitrofor Therapy of Duchenne Muscular Dystrophy. Hum Gene Ther 2009; 20:641-50. [DOI: 10.1089/hum.2008.162] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Louise H. Jørgensen
- Institute of Human Genetics, University of Newcastle, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Nancy Larochelle
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Kristian Orlopp
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
| | - Patrick Dunant
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
| | - Roy W.R. Dudley
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, QC H3A 2B4, Canada
| | - Rolf Stucka
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
| | - Christian Thirion
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
| | - Maggie C. Walter
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
| | - Steven H. Laval
- Institute of Human Genetics, University of Newcastle, Newcastle upon Tyne NE1 3BZ, United Kingdom
| | - Hanns Lochmüller
- Institute of Human Genetics, University of Newcastle, Newcastle upon Tyne NE1 3BZ, United Kingdom
- Friedrich Baur Institute and Department of Neurology, Ludwig Maximilians University, Munich 81377, Germany
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