Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 42
Filtrar
1.
RNA ; 25(4): 481-495, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30700578

RESUMO

Myotonic dystrophy type 1 (DM1) is a complex neuromuscular disorder caused by expansion of a CTG repeat in the 3'-untranslated region (UTR) of the DMPK gene. Mutant DMPK transcripts form aberrant structures and anomalously associate with RNA-binding proteins (RBPs). As a first step toward better understanding of the involvement of abnormal DMPK mRNA folding in DM1 manifestation, we used SHAPE, DMS, CMCT, and RNase T1 structure probing in vitro for modeling of the topology of the DMPK 3'-UTR with normal and pathogenic repeat lengths of up to 197 CUG triplets. The resulting structural information was validated by disruption of base-pairing with LNA antisense oligonucleotides (AONs) and used for prediction of therapeutic AON accessibility and verification of DMPK knockdown efficacy in cells. Our model for DMPK RNA structure demonstrates that the hairpin formed by the CUG repeat has length-dependent conformational plasticity, with a structure that is guided by and embedded in an otherwise rigid architecture of flanking regions in the DMPK 3'-UTR. Evidence is provided that long CUG repeats may form not only single asymmetrical hairpins but also exist as branched structures. These newly identified structures have implications for DM1 pathogenic mechanisms, like sequestration of RBPs and repeat-associated non-AUG (RAN) translation.


Assuntos
Regiões 3' não Traduzidas , Sequências Repetidas Invertidas , Miotonina Proteína Quinase/genética , Repetições de Trinucleotídeos , Pareamento de Bases , Expressão Gênica , Humanos , Modelos Genéticos , Distrofia Miotônica/genética , Distrofia Miotônica/metabolismo , Distrofia Miotônica/patologia , Miotonina Proteína Quinase/metabolismo , Conformação de Ácido Nucleico , Oligonucleotídeos/genética , Oligonucleotídeos/metabolismo , Oligonucleotídeos Antissenso/síntese química , Oligonucleotídeos Antissenso/genética , Oligonucleotídeos Antissenso/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
2.
FASEB J ; 33(10): 11314-11325, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31311315

RESUMO

Antisense oligonucleotides (ASOs) are a promising class of therapeutics that are starting to emerge in the clinic. Determination of intracellular concentrations required for biologic effects and identification of effective delivery vehicles are crucial for understanding the mode of action and required dosing. Here, we investigated which nuclear oligonucleotide concentration is needed for a therapeutic effect for a triplet repeat-targeting ASO in a muscle cell model of myotonic dystrophy type 1 (DM1). For cellular delivery, ASOs were complexed into nanoparticles using the cationic cell-penetrating peptides nona-arginine and PepFect14 (PF14). Although both peptides facilitated uptake, only PF14 led to a dose-dependent correction of disease-typical abnormal splicing. In line with this observation, time-lapse confocal microscopy demonstrated that only PF14 mediated translocation of the ASOs to the nucleus, which is the main site of action. Through fluorescence lifetime imaging, we could distinguish intact oligonucleotide from free fluorophore, showing that PF14 also shielded the ASOs from degradation. Finally, we employed a combination of live-cell fluorescence correlation spectroscopy and immunofluorescence microscopy and demonstrated that intranuclear blocking-type oligonucleotide concentrations in the upper nanomolar range were required to dissolve nuclear muscleblind-like protein 1 foci, a hallmark of DM1. Our findings have important implications for the clinical use of ASOs in DM1 and provide a basis for further research on other types of ASOs.-Van der Bent, M. L., Paulino da Silva Filho, O., Willemse, M., Hällbrink, M., Wansink, D. G., Brock, R. The nuclear concentration required for antisense oligonucleotide activity in myotonic dystrophy cells.


Assuntos
Núcleo Celular/genética , Distrofia Miotônica/genética , Oligonucleotídeos Antissenso/genética , Células Cultivadas , Humanos , Músculo Esquelético/fisiologia , Mioblastos/fisiologia , Oligonucleotídeos/genética
3.
BMC Med Educ ; 19(1): 178, 2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31151456

RESUMO

BACKGROUND: Study motivation and knowledge retention benefit from regular student self-assessments. Inclusion of certainty-based learning (CBL) in computer-assisted formative tests may further enhance this by enabling students to identify whether they are uninformed or misinformed regarding the topics tested, which may trigger future study actions including instructor consultation. METHODS: Using a cross-over study design involving two out of thirteen computer-assisted formative assessments (CAFAs) of a first-year cell biology course, we compared student-instructor interactions, student learning experiences and final exam scores between two (bio)medical science student cohorts who worked with different CBL-containing CAFAs. RESULTS: A total of 389 students participated in the study. After completion 159 (41%) filled in a questionnaire on their experience with CBL during supervised CAFAs. In the control group the median duration of student-instructor interactions was 90 s (range 60-140 s), and this increased with 20 s to 110 s (range 60-150 s) in the group working with a CBL-based CAFA. The number of interactions was similar in both groups (0.22 per student per hour, regardless of CBL inclusion). Forty percent of the students expected that CBL would positively influence their study behavior, and 23% also anticipated a positive effect on examination scores. Student examination scores, however, were not affected by CBL. Almost half of the students (43%) were in favor of CBL inclusion in future computer-assisted learning modules, whereas 33% did not see merit in including CBL in CAFAs. CONCLUSIONS: Incorporation of CBL in a single formative assessment led to a slight increase in student-instructor interaction times, but had effect neither on the number of student-instructor interactions nor on exam scores. CBL inclusion positively influenced student's appreciation of the coursework, presumably by helping students to evaluate their mastery level and identify misconceptions. A more extensive enrollment of CBL beyond an individual formative assessment, throughout a course or a curriculum, may possibly reveal positive effects on study efficacy.


Assuntos
Avaliação Educacional/métodos , Estudantes de Medicina/psicologia , Adolescente , Instrução por Computador/métodos , Estudos Cross-Over , Feminino , Feedback Formativo , Humanos , Masculino , Adulto Jovem
4.
Int J Mol Sci ; 20(15)2019 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-31357652

RESUMO

CRISPR/Cas technology holds promise for the development of therapies to treat inherited diseases. Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disorder with a variable multisystemic character for which no cure is yet available. Here, we review CRISPR/Cas-mediated approaches that target the unstable (CTG•CAG)n repeat in the DMPK/DM1-AS gene pair, the autosomal dominant mutation that causes DM1. Expansion of the repeat results in a complex constellation of toxicity at the DNA level, an altered transcriptome and a disturbed proteome. To restore cellular homeostasis and ameliorate DM1 disease symptoms, CRISPR/Cas approaches were directed at the causative mutation in the DNA and the RNA. Specifically, the triplet repeat has been excised from the genome by several laboratories via dual CRISPR/Cas9 cleavage, while one group prevented transcription of the (CTG)n repeat through homology-directed insertion of a polyadenylation signal in DMPK. Independently, catalytically deficient Cas9 (dCas9) was recruited to the (CTG)n repeat to block progression of RNA polymerase II and a dCas9-RNase fusion was shown to degrade expanded (CUG)n RNA. We compare these promising developments in DM1 with those in other microsatellite instability diseases. Finally, we look at hurdles that must be taken to make CRISPR/Cas-mediated editing a therapeutic reality in patients.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Terapia Genética , Distrofia Miotônica/genética , Distrofia Miotônica/terapia , Animais , Terapia Baseada em Transplante de Células e Tecidos , Marcação de Genes , Estudos de Associação Genética , Loci Gênicos , Predisposição Genética para Doença , Humanos , Expansão das Repetições de Trinucleotídeos , Repetições de Trinucleotídeos
5.
Int J Mol Sci ; 20(22)2019 Nov 13.
Artigo em Inglês | MEDLINE | ID: mdl-31766224

RESUMO

The congenital form of myotonic dystrophy type 1 (cDM) is caused by the large-scale expansion of a (CTG•CAG)n repeat in DMPK and DM1-AS. The production of toxic transcripts with long trinucleotide tracts from these genes results in impairment of the myogenic differentiation capacity as cDM's most prominent morpho-phenotypic hallmark. In the current in vitro study, we compared the early differentiation programs of isogenic cDM myoblasts with and without a (CTG)2600 repeat obtained by gene editing. We found that excision of the repeat restored the ability of cDM myoblasts to engage in myogenic fusion, preventing the ensuing myotubes from remaining immature. Although the cDM-typical epigenetic status of the DM1 locus and the expression of genes therein were not altered upon removal of the repeat, analyses at the transcriptome and proteome level revealed that early abnormalities in the temporal expression of differentiation regulators, myogenic progression markers, and alternative splicing patterns before and immediately after the onset of differentiation became normalized. Our observation that molecular and cellular features of cDM are reversible in vitro and can be corrected by repeat-directed genome editing in muscle progenitors, when already committed and poised for myogenic differentiation, is important information for the future development of gene therapy for different forms of myotonic dystrophy type 1 (DM1).


Assuntos
Mioblastos/patologia , Distrofia Miotônica/genética , Repetições de Trinucleotídeos , Linhagem Celular , Epigênese Genética , Edição de Genes , Terapia Genética , Humanos , Desenvolvimento Muscular , Mioblastos/citologia , Mioblastos/metabolismo , Distrofia Miotônica/patologia , Distrofia Miotônica/terapia , Miotonina Proteína Quinase/genética
6.
Hum Mol Genet ; 25(8): 1648-62, 2016 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-26908607

RESUMO

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 HSA(LR) 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 HSA(LR) 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.


Assuntos
Perfilação da Expressão Gênica/métodos , Músculo Esquelético/citologia , Distrofia Miotônica/genética , RNA Mensageiro/genética , Expansão das Repetições de Trinucleotídeos , Actinas/genética , Animais , Células Cultivadas , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Camundongos , Desenvolvimento Muscular , Músculo Esquelético/patologia , Distrofia Miotônica/patologia , Miotonina Proteína Quinase/genética , Miotonina Proteína Quinase/metabolismo
7.
Mol Ther ; 25(1): 24-43, 2017 01 04.
Artigo em Inglês | MEDLINE | ID: mdl-28129118

RESUMO

Myotonic dystrophy type 1 (DM1) is caused by (CTG⋅CAG)n-repeat expansion within the DMPK gene and thought to be mediated by a toxic RNA gain of function. Current attempts to develop therapy for this disease mainly aim at destroying or blocking abnormal properties of mutant DMPK (CUG)n RNA. Here, we explored a DNA-directed strategy and demonstrate that single clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-cleavage in either its 5' or 3' unique flank promotes uncontrollable deletion of large segments from the expanded trinucleotide repeat, rather than formation of short indels usually seen after double-strand break repair. Complete and precise excision of the repeat tract from normal and large expanded DMPK alleles in myoblasts from unaffected individuals, DM1 patients, and a DM1 mouse model could be achieved at high frequency by dual CRISPR/Cas9-cleavage at either side of the (CTG⋅CAG)n sequence. Importantly, removal of the repeat appeared to have no detrimental effects on the expression of genes in the DM1 locus. Moreover, myogenic capacity, nucleocytoplasmic distribution, and abnormal RNP-binding behavior of transcripts from the edited DMPK gene were normalized. Dual sgRNA-guided excision of the (CTG⋅CAG)n tract by CRISPR/Cas9 technology is applicable for developing isogenic cell lines for research and may provide new therapeutic opportunities for patients with DM1.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Instabilidade Genômica , Distrofia Miotônica/genética , Miotonina Proteína Quinase/genética , Expansão das Repetições de Trinucleotídeos , Repetições de Trinucleotídeos , Animais , Proteínas de Bactérias/genética , Sequência de Bases , Proteína 9 Associada à CRISPR , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Códon , Modelos Animais de Doenças , Endonucleases/genética , Fibroblastos/metabolismo , Expressão Gênica , Ordem dos Genes , Loci Gênicos , Humanos , Camundongos , RNA Guia de Cinetoplastídeos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Deleção de Sequência
8.
RNA Biol ; 14(10): 1374-1388, 2017 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-28102759

RESUMO

The unstable (CTG·CAG)n trinucleotide repeat in the myotonic dystrophy type 1 (DM1) locus is bidirectionally transcribed from genes with terminal overlap. By transcription in the sense direction, the DMPK gene produces various alternatively spliced mRNAs with a (CUG)n repeat in their 3' UTR. Expression in opposite orientation reportedly yields (CAG)n-repeat containing RNA, but both structure and biologic significance of this antisense gene (DM1-AS) are largely unknown. Via a combinatorial approach of computational and experimental analyses of RNA from unaffected individuals and DM1 patients we discovered that DM1-AS spans >6 kb, contains alternative transcription start sites and uses alternative polyadenylation sites up- and downstream of the (CAG)n repeat. Moreover, its primary transcripts undergo alternative splicing, whereby the (CAG)n segment is removed as part of an intron. Thus, in patients a mixture of DM1-AS RNAs with and without expanded (CAG)n repeat are produced. DM1-AS expression appears upregulated in patients, but transcript abundance remains very low in all tissues analyzed. Our data suggest that DM1-AS transcripts belong to the class of long non-coding RNAs. These and other biologically relevant implications for how (CAG)n-expanded transcripts may contribute to DM1 pathology can now be explored experimentally.


Assuntos
Distrofia Miotônica/genética , Miotonina Proteína Quinase/genética , RNA Antissenso/genética , RNA Mensageiro/química , Expansão das Repetições de Trinucleotídeos , Regiões 3' não Traduzidas , Adolescente , Processamento Alternativo , Estudos de Casos e Controles , Linhagem Celular , Biologia Computacional/métodos , Humanos , Masculino , Miotonina Proteína Quinase/química , Fases de Leitura Aberta , Poliadenilação , RNA Antissenso/química , RNA Longo não Codificante/genética , RNA Mensageiro/genética , Sítio de Iniciação de Transcrição , Regulação para Cima
9.
Nat Genet ; 39(2): 251-8, 2007 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17237782

RESUMO

In mammalian males, the first meiotic prophase is characterized by formation of a separate chromatin domain called the sex body. In this domain, the X and Y chromosomes are partially synapsed and transcriptionally silenced, a process termed meiotic sex-chromosome inactivation (MSCI). Likewise, unsynapsed autosomal chromatin present during pachytene is also silenced (meiotic silencing of unsynapsed chromatin, MSUC). Although it is known that MSCI and MSUC are both dependent on histone H2A.X phosphorylation mediated by the kinase ATR, and cause repressive H3 Lys9 dimethylation, the mechanisms underlying silencing are largely unidentified. Here, we demonstrate an extensive replacement of nucleosomes within unsynapsed chromatin, depending on and initiated shortly after induction of MSCI and MSUC. Nucleosomal eviction results in the exclusive incorporation of the H3.3 variant, which to date has primarily been associated with transcriptional activity. Nucleosomal exchange causes loss and subsequent selective reacquisition of specific histone modifications. This process therefore provides a means for epigenetic reprogramming of sex chromatin presumably required for gene silencing in the male mammalian germ line.


Assuntos
Histonas/metabolismo , Meiose , Nucleossomos , Cromossomos Sexuais , Animais , Cromatina/metabolismo , Inativação Gênica , Masculino , Camundongos , Camundongos Transgênicos , Estágio Paquíteno , Estrutura Terciária de Proteína , Espermatócitos/ultraestrutura , Cromossomo Y
10.
Stem Cell Res Ther ; 15(1): 302, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-39278936

RESUMO

BACKGROUND: Cell-based strategies are being explored as a therapeutic option for muscular dystrophies, using a variety of cell types from different origin and with different characteristics. Primary pericytes are multifunctional cells found in the capillary bed that exhibit stem cell-like and myogenic regenerative properties. This unique combination allows them to be applied systemically, presenting a promising opportunity for body-wide muscle regeneration. We previously reported the successful isolation of ALP+ pericytes from skeletal muscle of patients with myotonic dystrophy type 1 (DM1). These pericytes maintained normal growth parameters and myogenic characteristics in vitro despite the presence of nuclear (CUG)n RNA foci, the cellular hallmark of DM1. Here, we examined the behaviour of DM1 pericytes during myogenic differentiation. METHODS: DMPK (CTG)n repeat lengths in patient pericytes were assessed using small pool PCR, to be able to relate variation in myogenic properties and disease hallmarks to repeat expansion. Pericytes from unaffected controls and DM1 patients were cultured under differentiating conditions in vitro. In addition, the pericytes were grown in co-cultures with myoblasts to examine their regenerative capacity by forming hybrid myotubes. Finally, the effect of pericyte fusion on DM1 disease hallmarks was investigated. RESULTS: Small pool PCR analysis revealed the presence of somatic mosaicism in pericyte cell pools. Upon differentiation to myotubes, DMPK expression was upregulated, leading to an increase in nuclear foci sequestering MBNL1 protein. Remarkably, despite the manifestation of these disease biomarkers, patient-derived pericytes demonstrated myogenic potential in co-culture experiments comparable to unaffected pericytes and myoblasts. However, only the unaffected pericytes improved the disease hallmarks in hybrid myotubes. From 20% onwards, the fraction of unaffected nuclei in myotubes positively correlated with a reduction of the number of RNA foci and an increase in the amount of free MBNL1. CONCLUSIONS: Fusion of only a limited number of unaffected myogenic precursors to DM1 myotubes already ameliorates cellular disease hallmarks, offering promise for the development of cell transplantation strategies to lower disease burden.


Assuntos
Diferenciação Celular , Fibras Musculares Esqueléticas , Distrofia Miotônica , Miotonina Proteína Quinase , Pericitos , Humanos , Distrofia Miotônica/metabolismo , Distrofia Miotônica/genética , Distrofia Miotônica/terapia , Distrofia Miotônica/patologia , Fibras Musculares Esqueléticas/metabolismo , Pericitos/metabolismo , Miotonina Proteína Quinase/genética , Miotonina Proteína Quinase/metabolismo , Mioblastos/metabolismo , Mioblastos/citologia , Desenvolvimento Muscular , Células Cultivadas , Masculino , Adulto , Feminino , Técnicas de Cocultura , Pessoa de Meia-Idade , Fusão Celular
11.
Nat Commun ; 15(1): 3270, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38627364

RESUMO

Epigenetic defects caused by hereditary or de novo mutations are implicated in various human diseases. It remains uncertain whether correcting the underlying mutation can reverse these defects in patient cells. Here we show by the analysis of myotonic dystrophy type 1 (DM1)-related locus that in mutant human embryonic stem cells (hESCs), DNA methylation and H3K9me3 enrichments are completely abolished by repeat excision (CTG2000 expansion), whereas in patient myoblasts (CTG2600 expansion), repeat deletion fails to do so. This distinction between undifferentiated and differentiated cells arises during cell differentiation, and can be reversed by reprogramming of gene-edited myoblasts. We demonstrate that abnormal methylation in DM1 is distinctively maintained in the undifferentiated state by the activity of the de novo DNMTs (DNMT3b in tandem with DNMT3a). Overall, the findings highlight a crucial difference in heterochromatin maintenance between undifferentiated (sequence-dependent) and differentiated (sequence-independent) cells, thus underscoring the role of differentiation as a locking mechanism for repressive epigenetic modifications at the DM1 locus.


Assuntos
Distrofia Miotônica , Humanos , Distrofia Miotônica/genética , Heterocromatina/genética , Diferenciação Celular/genética , Metilação de DNA , Epigênese Genética
12.
Mol Ther Nucleic Acids ; 32: 622-636, 2023 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-37200862

RESUMO

Antisense oligonucleotide (ASO) therapies for myotonic dystrophy type 1 (DM1) are based on elimination of transcripts containing an expanded repeat or inhibition of sequestration of RNA-binding proteins. This activity is achievable by both degradation of expanded transcripts and steric hindrance, although it is unknown which approach is superior. We compared blocking ASOs with RNase H-recruiting gapmers of equivalent chemistries. Two DMPK target sequences were selected: the triplet repeat and a unique sequence upstream thereof. We assessed ASO effects on transcript levels, ribonucleoprotein foci and disease-associated missplicing, and performed RNA sequencing to investigate on- and off-target effects. Both gapmers and the repeat blocker led to significant DMPK knockdown and a reduction in (CUG)exp foci. However, the repeat blocker was more effective in MBNL1 protein displacement and had superior efficiency in splicing correction at the tested dose of 100 nM. By comparison, on a transcriptome level, the blocking ASO had the fewest off-target effects. In particular, the off-target profile of the repeat gapmer asks for cautious consideration in further therapeutic development. Altogether, our study demonstrates the importance of evaluating both on-target and downstream effects of ASOs in a DM1 context, and provides guiding principles for safe and effective targeting of toxic transcripts.

13.
Biochim Biophys Acta ; 1813(5): 867-77, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21295081

RESUMO

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.


Assuntos
Actomiosina/metabolismo , Diferenciação Celular , Citosol/enzimologia , Mioblastos/citologia , Mioblastos/enzimologia , Proteínas Serina-Treonina Quinases/metabolismo , Actinas/química , Actinas/metabolismo , Animais , Movimento Celular , Polaridade Celular , Proliferação de Células , Forma Celular , Isoenzimas/metabolismo , Camundongos , Desenvolvimento Muscular , Miosina Tipo II/metabolismo , Miotonina Proteína Quinase , Fosforilação , Estrutura Quaternária de Proteína , Transporte Proteico , Fibras de Estresse/metabolismo , Fibras de Estresse/ultraestrutura , Frações Subcelulares/metabolismo
14.
J Cell Biochem ; 113(6): 2126-35, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22492269

RESUMO

Serine/threonine kinases of the AGC group are important regulators of cell growth and motility. To examine the candidate substrate profile for two members of this group, DMPK E and Lats2, we performed in vitro kinase assays on peptide arrays. Substrate peptides for both kinases exhibited a predominance of basic residues surrounding the phosphorylation target site. 3D homology modeling of the kinase domains of DMPK E and Lats2 indicated that presence of two negative pockets in the peptide binding groove provides an explanation for the substrate preference. These findings will aid future research toward signaling functions of Lats2 and DMPK E within cells.


Assuntos
Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células COS , Linhagem Celular , Chlorocebus aethiops , Proteínas Quinases Dependentes de AMP Cíclico/química , Proteínas Quinases Dependentes de AMP Cíclico/genética , Modelos Moleculares , Miotonina Proteína Quinase , Fosforilação , Conformação Proteica , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/genética , Estrutura Terciária de Proteína , Transdução de Sinais , Especificidade por Substrato , Proteínas Supressoras de Tumor/genética
15.
Hum Mol Genet ; 19(R1): R90-7, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20406734

RESUMO

Myotonic dystrophy (DM) is a complex, dominantly inherited, multisystem disorder and the archetypal example of an RNA gain-of-function disease. Unstable expansions of (CTG*CAG)n or (CCTG*CAGG)n repeat tracts in the DMPK and ZNF9 genes cause the two known subtypes of myotonic dystrophy, DM1 and DM2, for which no cure or effective molecular treatment exists. Focus in therapeutic development is currently on toxic, expanded (C/CUG)n RNAs. A series of recent papers provide proof of concept of promising strategies using antisense oligonucleotides or small organic compounds aimed at either complete elimination of expanded (CUG)n RNA transcripts or prevention of detrimental protein binding to thermodynamically stable (C/CUG)n hairpin structures. These developments offer new hope to patients with DM, even though several hurdles still have to be overcome before they can be introduced into clinical practice.


Assuntos
Distrofia Miotônica/tratamento farmacológico , RNA Mensageiro/genética , Humanos , Distrofia Miotônica/genética , Miotonina Proteína Quinase , Ligação Proteica , Proteínas Serina-Treonina Quinases/genética , Interferência de RNA , Proteínas de Ligação a RNA/genética
16.
Proc Natl Acad Sci U S A ; 106(33): 13915-20, 2009 Aug 18.
Artigo em Inglês | MEDLINE | ID: mdl-19667189

RESUMO

Myotonic dystrophy type 1 (DM1) is caused by toxicity of an expanded, noncoding (CUG)n tract in DM protein kinase (DMPK) transcripts. According to current evidence the long (CUG)n segment is involved in entrapment of muscleblind (Mbnl) proteins in ribonuclear aggregates and stabilized expression of CUG binding protein 1 (CUGBP1), causing aberrant premRNA splicing and associated pathogenesis in DM1 patients. Here, we report on the use of antisense oligonucleotides (AONs) in a therapeutic strategy for reversal of RNA-gain-of-function toxicity. Using a previously undescribed mouse DM1 myoblast-myotube cell model and DM1 patient cells as screening tools, we have identified a fully 2'-O-methyl-phosphorothioate-modified (CAG)7 AON that silences mutant DMPK RNA expression and reduces the number of ribonuclear aggregates in a selective and (CUG)n-length-dependent manner. Direct administration of this AON in muscle of DM1 mouse models in vivo caused a significant reduction in the level of toxic (CUG)n RNA and a normalizing effect on aberrant premRNA splicing. Our data demonstrate proof of principle for therapeutic use of simple sequence AONs in DM1 and potentially other unstable microsatellite diseases.


Assuntos
Distrofia Miotônica/genética , Oligonucleotídeos/genética , RNA/genética , Alelos , Animais , Proteínas CELF1 , Inativação Gênica , Camundongos , Modelos Genéticos , Músculo Esquelético/metabolismo , Mutação , Mioblastos/metabolismo , Distrofia Miotônica/terapia , Oligonucleotídeos/química , Oligonucleotídeos Antissenso/genética , Interferência de RNA , Splicing de RNA , Proteínas de Ligação a RNA/genética
17.
Methods Mol Biol ; 2383: 197-210, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34766291

RESUMO

Cationic cell-penetrating peptides spontaneously associate with negatively charged oligonucleotides to form submicron nanoparticles, so-called polyplexes. Contact with cells leads to endosomal uptake of these nanoparticles. Oligonucleotide activity critically depends on endosomal release and finally dissociation of polyplexes. Fluorescence provides a highly powerful means to follow the spatial dynamics of oligonucleotide uptake, trafficking and decomplexation, in particular when combined with markers of subcellular compartments that enable a quantitative analysis of colocalization and thereby mapping of trafficking routes. In this chapter, we describe protocols for a highly defined formation of polyplexes. We then point out the use of fluorescent fusion proteins to identify subcellular trafficking compartments and image analysis protocols to obtain quantitative information on trafficking routes and endosomal release.


Assuntos
Peptídeos Penetradores de Células , Peptídeos Penetradores de Células/metabolismo , Endossomos , Oligonucleotídeos , Oligonucleotídeos Antissenso
18.
NAR Genom Bioinform ; 4(1): lqac016, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35274098

RESUMO

In patients with myotonic dystrophy type 1 (DM1), dysregulation of RNA-binding proteins like MBNL and CELF1 leads to alternative splicing of exons and is thought to induce a return to fetal splicing patterns in adult tissues, including the central nervous system (CNS). To comprehensively evaluate this, we created an atlas of developmentally regulated splicing patterns in the frontal cortex of healthy individuals and DM1 patients, by combining RNA-seq data from BrainSpan, GTEx and DM1 patients. Thirty-four splice events displayed an inclusion pattern in DM1 patients that is typical for the fetal situation in healthy individuals. The regulation of DM1-relevant splicing patterns could partly be explained by changes in mRNA expression of the splice regulators MBNL1, MBNL2 and CELF1. On the contrary, interindividual differences in splicing patterns between healthy adults could not be explained by differential expression of these splice regulators. Our findings lend transcriptome-wide evidence to the previously noted shift to fetal splicing patterns in the adult DM1 brain as a consequence of an imbalance in antagonistic MBNL and CELF1 activities. Our atlas serves as a solid foundation for further study and understanding of the cognitive phenotype in patients.

19.
J Cell Biochem ; 112(6): 1612-21, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21344488

RESUMO

The mismatch repair protein, MSH3, together with MSH2, forms the MutSß heterodimer which recognizes and repairs base pair mismatches and larger insertion/deletion loops in DNA. Lack of specific antibodies against mouse MSH3 has hampered studies of its expression and localization. Mouse MSH3 is not immunogenic in normal mice. This problem was overcome by immunizing msh3-knockout mice and generating a panel of ten monoclonal antibodies, two of which localize MSH3 specifically in cultured mouse cells and bind to an epitope containing amino-acids 33-37. The panel also includes two antibodies that recognise both mouse and human MSH3 and bind to a conserved epitope containing amino-acids 187-194. The mouse MSH3-specific antibodies show that MSH3 is a nuclear protein with a finely-granular nucleoplasmic distribution, largely absent from areas of condensed heterochromatin. Specificity of the localization was demonstrated by absence of immunostaining in a cell line from the msh3-knockout mouse. Furthermore, we show for the first time that stress treatment of mouse cells with ethanol or hydrogen peroxide caused the re-distribution of MSH3 into nuclear bodies containing the proliferating cell nuclear antigen (PCNA), a known binding partner of MutSß.


Assuntos
Núcleo Celular/metabolismo , Proteínas/metabolismo , Animais , Anticorpos Monoclonais , Western Blotting , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos , Células HeLa , Humanos , Hibridomas , Peróxido de Hidrogênio/farmacologia , Camundongos , Camundongos Knockout , Proteína 3 Homóloga a MutS , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Antígeno Nuclear de Célula em Proliferação/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas/genética
20.
Stem Cell Rev Rep ; 17(3): 878-899, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33349909

RESUMO

The intrinsic regenerative capacity of skeletal muscle makes it an excellent target for cell therapy. However, the potential of muscle tissue to renew is typically exhausted and insufficient in muscular dystrophies (MDs), a large group of heterogeneous genetic disorders showing progressive loss of skeletal muscle fibers. Cell therapy for MDs has to rely on suppletion with donor cells with high myogenic regenerative capacity. Here, we provide an overview on stem cell lineages employed for strategies in MDs, with a focus on adult stem cells and progenitor cells resident in skeletal muscle. In the early days, the potential of myoblasts and satellite cells was explored, but after disappointing clinical results the field moved to other muscle progenitor cells, each with its own advantages and disadvantages. Most recently, mesoangioblasts and pericytes have been pursued for muscle cell therapy, leading to a handful of preclinical studies and a clinical trial. The current status of (pre)clinical work for the most common forms of MD illustrates the existing challenges and bottlenecks. Besides the intrinsic properties of transplantable cells, we discuss issues relating to cell expansion and cell viability after transplantation, optimal dosage, and route and timing of administration. Since MDs are genetic conditions, autologous cell therapy and gene therapy will need to go hand-in-hand, bringing in additional complications. Finally, we discuss determinants for optimization of future clinical trials for muscle cell therapy. Joined research efforts bring hope that effective therapies for MDs are on the horizon to fulfil the unmet clinical need in patients.


Assuntos
Distrofias Musculares , Terapia Baseada em Transplante de Células e Tecidos , Humanos , Músculos , Distrofias Musculares/terapia , Mioblastos , Células-Tronco , Resultado do Tratamento
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA