RESUMO
Transthyretin-mediated amyloidosis (ATTR) is a systemic disease with protein precipitation in many tissues, mainly the peripheral nerve and heart. Both genetic (ATTRv, "v" for variant) and wild-type (ATTRwt) forms are known. Beyond the steric encumbrance, precipitated transthyretin seems to have a toxic effect. In this study carried out in men, we recruited 15 ATTRv patients, 7 ATTRv asymptomatic carriers, 14 ATTRwt patients and 10 young and 13 old healthy controls to evaluate the oxidative stress using FORD (Free Oxygen Radicals Defense) and FORT (Free Oxygen Radicals Test) analyses. ATTRv patients showed reduced FORD compared to ATTRwt and ATTRv asymptomatic carriers. FORD independently predicted the disease stage, with the early stages characterized by the highest consumption. These findings suggest a role for oxidative stress in the early stages of ATTRv.
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The deficiency of survival motor neuron protein (SMN) causes spinal muscular atrophy (SMA), a rare neuromuscular disease that affects different organs. SMN is a key player in RNA metabolism regulation. An intriguing aspect of SMN function is its relationship with plasma membrane-associated proteins. Here, we provide a first demonstration that SMN affects the ATP-binding cassette transporter A1, (ABCA1), a membrane protein critically involved in cholesterol homeostasis. In human fibroblasts, we showed that SMN associates to ABCA1 mRNA, and impacts its subcellular distribution. Consistent with the central role of ABCA1 in the efflux of free cholesterol from cells, we observed a cholesterol accumulation in SMN-depleted human fibroblasts. These results were also confirmed in SMA type I patient-derived fibroblasts. These findings not only validate the intimate connection between SMN and plasma membrane-associated proteins, but also highlight a contribution of dysregulated cholesterol efflux in SMA pathophysiology.
Assuntos
Neurônios Motores , Atrofia Muscular Espinal , Humanos , Neurônios Motores/metabolismo , Atrofia Muscular Espinal/metabolismo , Fatores de Transcrição/metabolismo , Fibroblastos/metabolismo , Proteínas de Membrana/metabolismo , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Transportador 1 de Cassete de Ligação de ATP/metabolismoRESUMO
Head and neck squamous cell carcinoma (HNSCC) arises from the mucosal epithelium in the oral cavity, pharynx, sino-nasal region, and larynx. Laryngeal squamous cell carcinoma (LSCC) represents one-third of all head and neck cancers. Dysregulated RNA-related pathways define an important molecular signature in this aggressive carcinoma. The Survival Motor Neuron (SMN) protein regulates fundamental aspects of the RNA metabolism but, curiously, its role in cancer is virtually unknown. For the first time, here, we focus on the SMN in the cancer context. We conducted a pilot study in a total of 20 patients with LSCC where the SMN was found overexpressed at both the protein and transcript levels. By a cellular model of human laryngeal carcinoma, we demonstrated that the SMN impacts cancer-relevant behaviors and perturbs key players of cell migration, invasion, and adhesion. Furthermore, in LSCC we showed a physical interaction between the SMN and the epidermal growth factor receptor (EGFR), whose overexpression is an important feature in these tumors. This study proposes the SMN protein as a novel therapeutic target in LSSC and likely in the whole spectrum of HNSCC. Overall, we provide the first analysis of the SMN in human cancer.
Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Laríngeas , Humanos , Carcinoma de Células Escamosas de Cabeça e Pescoço/genética , Carcinoma de Células Escamosas/patologia , Projetos Piloto , Neoplasias de Cabeça e Pescoço/genética , Neoplasias Laríngeas/metabolismo , RNA , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica , Proliferação de Células/genéticaRESUMO
The ongoing COVID-19 pandemic dictated new priorities in biomedicine research. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of COVID-19, is a single-stranded positive-sense RNA virus. In this pilot study, we optimized our padlock assay to visualize genomic and subgenomic regions using formalin-fixed paraffin-embedded placental samples obtained from a confirmed case of COVID-19. SARS-CoV-2 RNA was localized in trophoblastic cells. We also checked the presence of the virion by immunolocalization of its glycoprotein spike. In addition, we imaged mitochondria of placental villi keeping in mind that the mitochondrion has been suggested as a potential residence of the SARS-CoV-2 genome. We observed a substantial overlapping of SARS-CoV-2 RNA and mitochondria in trophoblastic cells. This intriguing linkage correlated with an aberrant mitochondrial network. Overall, to the best of our knowledge, this is the first study that provides evidence of colocalization of the SARS-CoV-2 genome and mitochondria in SARS-CoV-2 infected tissue. These findings also support the notion that SARS-CoV-2 infection can reprogram mitochondrial activity in the highly specialized maternal-fetal interface.
Assuntos
Mitocôndrias/virologia , Técnicas de Amplificação de Ácido Nucleico/métodos , Placenta/virologia , RNA Viral/metabolismo , SARS-CoV-2/genética , Adulto , COVID-19/patologia , COVID-19/virologia , Sondas de DNA/metabolismo , Feminino , Humanos , Projetos Piloto , Placenta/patologia , Gravidez , SARS-CoV-2/isolamento & purificaçãoRESUMO
Increasing evidence points to the Survival Motor Neuron (SMN) protein as a key determinant of translation pathway. Besides its role in RNA processing and sorting, several works support a critical implication of SMN in ribosome biogenesis. We previously showed that SMN binds ribosomal proteins (RPs) as well as their encoding transcripts, ensuring an appropriate level of locally synthesized RPs. SMN impacts the translation machinery in both neural and non-neural cells, in agreement with the concept that SMN is an essential protein in all cell types. Here, we further assessed the relationship between SMN and translation-related factors in immortalized human fibroblasts. We focused on SMN-nucleolin interaction, keeping in mind that nucleolin is an RNA-binding protein, highly abundant within the nucleolus, that exhibits a central role in ribosomes production. Nucleolin may also affects translation network by binding the mammalian target of rapamycin (mTOR) mRNA and promoting its local synthesis. In this regard, for the first time we provided evidence that SMN protein itself associates with mTOR transcript. Collectively, we found that: (1) SMN coexists with nucleolin-mTOR mRNA complexes at subcellular level; (2) SMN deficiency impairs nucleolar compartmentalization of nucleolin, and (3) this event correlates with the nuclear retention of mTOR mRNA. These findings suggest that SMN may regulate not only structural components of translation machinery, but also their upstream regulating factors.
Assuntos
Fosfoproteínas/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteínas do Complexo SMN/metabolismo , Serina-Treonina Quinases TOR/genética , Linhagem Celular , Nucléolo Celular/metabolismo , Técnicas de Silenciamento de Genes , Humanos , Ligação Proteica , Biossíntese de Proteínas , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas do Complexo SMN/deficiência , Frações Subcelulares/metabolismo , Serina-Treonina Quinases TOR/metabolismo , NucleolinaRESUMO
Several types of cancer grow differently depending on the environmental stimuli they receive. In glioma, exposure to an enriched environment (EE) increases the overall survival rate of tumor-bearing mice, acting on the cells that participate to define the tumor microenvironment. In particular, environmental cues increase the microglial production of interleukin (IL)-15 which promotes a pro-inflammatory (antitumor) phenotype of microglia and the cytotoxic activity of natural killer (NK) cells, counteracting glioma growth, thus representing a virtuous mechanism of interaction between NK cells and microglia. To mimic the effect of EE on glioma, we investigated the potential of creating engineered microglia as the source of IL-15 in glioma. We demonstrated that microglia modified with recombinant adeno-associated virus serotype 2 (rAAV2) carrying IL-15 (rAAV2-IL-15), to force the production of IL-15, are able to increase the NK cells viability in coculture. Furthermore, the intranasal delivery of rAAV2-IL-15 microglia triggered the interplay with NK cells in vivo, enhancing NK cell recruitment and pro-inflammatory microglial phenotype in tumor mass of glioma-bearing mice, and ultimately counteracted tumor growth. This approach has a high potential for clinical translatability, highlighting the therapeutic efficacy of forced IL-15 production in microglia: the delivery of engineered rAAV2-IL-15 microglia to boost the immune response paves the way to design a new perspective therapy for glioma patients.
Assuntos
Neoplasias Encefálicas/terapia , Dependovirus/metabolismo , Terapia Genética , Glioma/terapia , Imunoterapia , Interleucina-15/metabolismo , Microglia/transplante , Microambiente Tumoral , Animais , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/imunologia , Neoplasias Encefálicas/metabolismo , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Técnicas de Cocultura , Citotoxicidade Imunológica , Dependovirus/genética , Dependovirus/imunologia , Engenharia Genética , Glioma/genética , Glioma/imunologia , Glioma/metabolismo , Interleucina-15/genética , Células Matadoras Naturais/imunologia , Células Matadoras Naturais/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microglia/imunologia , Microglia/metabolismo , Fenótipo , Transdução Genética , Carga TumoralRESUMO
CCHCR1 (Coiled-Coil alpha-Helical Rod 1), maps to chromosomal region 6p21.3, within the major psoriasis susceptibility locus PSORS1. CCHCR1 itself is a plausible psoriasis candidate gene, however its role in psoriasis pathogenesis remains unclear. We previously demonstrated that CCHCR1 protein acts as a cytoplasmic docking site for RNA polymerase II core subunit 3 (RPB3) in cycling cells, suggesting a role for CCHCR1 in vesicular trafficking between cellular compartments. Here, we report a novel interaction between CCHCR1 and the RNA binding protein HAX1. HAX1 maps to chromosomal region 1q21.3 within the PSORS4 locus and is over-expressed in psoriasis. Both CCHCR1 and HAX1 share subcellular co-localization with mitochondria, nuclei and cytoplasmic vesicles as P-bodies. By a series of ribonucleoprotein immunoprecipitation (RIP) assays, we isolated a pool of mRNAs complexed with HAX1 and/or CCHCR1 proteins. Among the mRNAs complexed with both CCHCR1 and HAX1 proteins, there are Vimentin mRNA, previously described to be bound by HAX1, and CAMP/LL37 mRNA, whose gene product is over-expressed in psoriasis.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Redes Reguladoras de Genes , Peptídeos e Proteínas de Sinalização Intracelular/genética , Mapas de Interação de Proteínas , Psoríase/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Células Cultivadas , Redes Reguladoras de Genes/genética , Loci Gênicos , Predisposição Genética para Doença/genética , Células HL-60 , Células HeLa , Humanos , Recém-Nascido , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Masculino , Polimorfismo de Nucleotídeo Único , Ligação Proteica , Mapas de Interação de Proteínas/genética , RNA Mensageiro/análise , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , CoelhosRESUMO
Up-regulation of the dystrophin-related gene utrophin represents a promising therapeutic strategy for the treatment of Duchenne Muscular Dystrophy (DMD). In order to re-program the utrophin expression level in muscle, we engineered artificial zinc finger transcription factors (ZF-ATFs) that target the utrophin 'A' promoter. We have previously shown that the ZF-ATF "Jazz", either by transgenic manipulation or by systemic adeno-associated viral delivery, induces significant rescue of muscle function in dystrophic "mdx" mice. We present the full characterization of an upgraded version of Jazz gene named "JZif1" designed to minimize any possible host immune response. JZif1 was engineered on the Zif268 gene-backbone using selective amino acid substitutions to address JZif1 to the utrophin 'A' promoter. Here, we show that JZif1 induces remarkable amelioration of the pathological phenotype in mdx mice. To investigate the molecular mechanisms underlying Jazz and JZif1 induced muscle functional rescue, we focused on utrophin related pathways. Coherently with utrophin subcellular localization and role in neuromuscular junction (NMJ) plasticity, we found that our ZF-ATFs positively impact the NMJ. We report on ZF-ATF effects on post-synaptic membranes in myogenic cell line, as well as in wild type and mdx mice. These results candidate our ZF-ATFs as novel therapeutic molecules for DMD treatment.
Assuntos
Terapia Genética/métodos , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/terapia , Junção Neuromuscular/metabolismo , Engenharia de Proteínas , Fatores de Transcrição , Regulação para Cima , Animais , Células HeLa , Humanos , Camundongos , Camundongos Endogâmicos mdx , Músculo Esquelético/patologia , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Junção Neuromuscular/genética , Junção Neuromuscular/patologia , Fatores de Transcrição/biossíntese , Fatores de Transcrição/genética , Utrofina/genética , Dedos de ZincoRESUMO
BACKGROUND: We have previously shown that the eukaryotic elongation factor subunit 1B gamma (eEF1Bγ) interacts with the RNA polymerase II (pol II) alpha-like subunit "C" (POLR2C), alone or complexed, in the pol II enzyme. Moreover, we demonstrated that eEF1Bγ binds the promoter region and the 3' UTR mRNA of the vimentin gene. These events contribute to localize the vimentin transcript and consequentially its translation, promoting a proper mitochondrial network. METHODS: With the intent of identifying additional transcripts that complex with the eEF1Bγ protein, we performed a series of ribonucleoprotein immunoprecipitation (RIP) assays using a mitochondria-enriched heavy membrane (HM) fraction. RESULTS: Among the eEF1Bγ complexed transcripts, we found the mRNA encoding the Che-1/AATF multifunctional protein. As reported by other research groups, we found the tumor suppressor p53 transcript complexed with the eEF1Bγ protein. Here, we show for the first time that eEF1Bγ binds not only Che-1 and p53 transcripts but also their promoters. Remarkably, we demonstrate that both the Che-1 transcript and its translated product localize also to the mitochondria and that eEF1Bγ depletion strongly perturbs the mitochondrial network and the correct localization of Che-1. In a doxorubicin (Dox)-induced DNA damage assay we show that eEF1Bγ depletion significantly decreases p53 protein accumulation and slightly impacts on Che-1 accumulation. Importantly, Che-1 and p53 proteins are components of the DNA damage response machinery that maintains genome integrity and prevents tumorigenesis. CONCLUSIONS: Our data support the notion that eEF1Bγ, besides its canonical role in translation, is an RNA-binding protein and a key player in cellular stress responses. We suggest for eEF1Bγ a role as primordial transcription/translation factor that links fundamental steps from transcription control to local translation.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Neoplasias/metabolismo , Fator 1 de Elongação de Peptídeos/metabolismo , Proteínas Repressoras/genética , Proteína Supressora de Tumor p53/genética , Regiões 3' não Traduzidas , Linhagem Celular Tumoral , Células HCT116 , Células HeLa , Humanos , Mitocôndrias/genética , Neoplasias/genética , Regiões Promotoras Genéticas , Estabilidade de RNA , RNA Mensageiro/química , RNA Mensageiro/metabolismoRESUMO
Transcriptional regulation is a key process in the formation of long-term memories. Che-1 is a protein involved in the regulation of gene transcription that has recently been proved to bind the transcription factor NF-κB, which is known to be involved in many memory-related molecular events. This evidence prompted us to investigate the putative role of Che-1 in memory processes. For this study we newly generated a line of Che-1(+/-) heterozygous mice. Che-1 homozygous KO mouse is lethal during development, but Che-1(+/-) heterozygous mouse is normal in its general anatomical and physiological characteristics. We analyzed the behavioral characteristic and memory performance of Che-1(+/-) mice in two NF-κB dependent types of memory. We found that Che-1(+/-) mice show similar locomotor activity and thigmotactic behavior than wild type (WT) mice in an open field. In a similar way, no differences were found in anxiety-like behavior between Che-1(+/-) and WT mice in an elevated plus maze as well as in fear response in a contextual fear conditioning (CFC) and object exploration in a novel object recognition (NOR) task. No differences were found between WT and Che-1(+/-) mice performance in CFC training and when tested at 24h or 7days after training. Similar performance was found between groups in NOR task, both in training and 24h testing performance. However, we found that object recognition memory persistence at 7days was impaired in Che-1(+/-) heterozygous mice. This is the first evidence showing that Che-1 is involved in memory processes.
Assuntos
Proteínas Reguladoras de Apoptose/genética , Memória/fisiologia , Reconhecimento Psicológico/fisiologia , Proteínas Repressoras/genética , Animais , Ansiedade/genética , Comportamento Animal/fisiologia , Condicionamento Psicológico/fisiologia , Medo/fisiologia , Heterozigoto , Camundongos , Camundongos Knockout , Atividade Motora/genéticaRESUMO
Disconnection between membrane signalling and actin networks can have catastrophic effects depending on cell size and polarity. The survival motor neuron (SMN) protein is ubiquitously involved in assembly of spliceosomal small nuclear ribonucleoprotein particles. Other SMN functions could, however, affect cellular activities driving asymmetrical cell surface expansions. Genes able to mitigate SMN deficiency operate within pathways in which SMN can act, such as mRNA translation, actin network and endocytosis. Here, we found that SMN accumulates at membrane protrusions during the dynamic rearrangement of the actin filaments. In addition to localization data, we show that SMN interacts with caveolin-1, which mediates anchoring of translation machinery components. Importantly, SMN deficiency depletes the plasma membrane of ribosomes, and this correlates with the failure of fibroblasts to extend membrane protrusions. These findings strongly support a relationship between SMN and membrane dynamics. We propose that SMN could assembly translational platforms associated with and governed by the plasma membrane. This activity could be crucial in cells that have an exacerbated interdependence of membrane remodelling and local protein synthesis.
Assuntos
Membrana Celular/metabolismo , Proteínas do Complexo SMN/fisiologia , Citoesqueleto de Actina/metabolismo , Caveolina 1/metabolismo , Membrana Celular/ultraestrutura , Extensões da Superfície Celular/metabolismo , Extensões da Superfície Celular/ultraestrutura , Células Cultivadas , Humanos , Biossíntese de Proteínas , Transporte Proteico , Ribossomos/metabolismoRESUMO
Numerous therapeutic approaches for Duchenne and Becker Muscular Dystrophy (DMD and BMD), the most common X-linked muscle degenerative disease, have been proposed. So far, the only one showing a clear beneficial effect is the use of corticosteroids. Recent evidence indicates an improvement of dystrophic cardiac and skeletal muscles in the presence of sustained cGMP levels secondary to a blocking of their degradation by phosphodiesterase five (PDE5). Due to these data, we performed a study to investigate the effect of the specific PDE5 inhibitor, tadalafil, on dystrophic skeletal muscle function. Chronic pharmacological treatment with tadalafil has been carried out in mdx mice. Behavioral and physiological tests, as well as histological and biochemical analyses, confirmed the efficacy of the therapy. We then performed a microarray-based genomic analysis to assess the pattern of gene expression in muscle samples obtained from the different cohorts of animals treated with tadalafil. This scrutiny allowed us to identify several classes of modulated genes. Our results show that PDE5 inhibition can ameliorate dystrophy by acting at different levels. Tadalafil can lead to (1) increased lipid metabolism; (2) a switch towards slow oxidative fibers driven by the up-regulation of PGC-1α; (3) an increased protein synthesis efficiency; (4) a better actin network organization at Z-disk.
Assuntos
Metabolismo dos Lipídeos/efeitos dos fármacos , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/metabolismo , Inibidores da Fosfodiesterase 5/farmacologia , Tadalafila/farmacologia , Animais , Feminino , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/genética , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo , Fatores de Transcrição/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
Over-expression of the dystrophin-related gene utrophin represents a promising therapeutic strategy for Duchenne muscular dystrophy (DMD). The strategy is based on the ability of utrophin to functionally replace defective dystrophin. We developed the artificial zinc finger transcription factor "Jazz" that up-regulates both the human and mouse utrophin promoter. We observed a significant recovery of muscle strength in dystrophic Jazz-transgenic mdx mice. Here we demonstrate the efficacy of an experimental gene therapy based on the systemic delivery of Jazz gene in mdx mice by adeno-associated virus (AAV). AAV serotype 8 was chosen on the basis of its high affinity for skeletal muscle. Muscle-specific expression of the therapeutic Jazz gene was enhanced by adding the muscle α-actin promoter to the AAV vector (mAAV). Injection of mAAV8-Jazz viral preparations into mdx mice resulted in muscle-specific Jazz expression coupled with up-regulation of the utrophin gene. We show a significant recovery from the dystrophic phenotype in mAAV8-Jazz-treated mdx mice. Histological and physiological analysis revealed a reduction of fiber necrosis and inflammatory cell infiltration associated with functional recovery in muscle contractile force. The combination of ZF-ATF technology with the AAV delivery can open a new avenue to obtain a therapeutic strategy for treatment of DMD.
Assuntos
Dependovirus/genética , Técnicas de Transferência de Genes , Terapia Genética/métodos , Vetores Genéticos , Músculo Esquelético/metabolismo , Distrofia Muscular de Duchenne/terapia , Proteínas Recombinantes de Fusão/biossíntese , Fatores de Transcrição/biossíntese , Utrofina/metabolismo , Dedos de Zinco , Actinas/genética , Animais , Modelos Animais de Doenças , Genótipo , Humanos , Camundongos , Camundongos Endogâmicos mdx , Contração Muscular , Força Muscular , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Distrofia Muscular de Duchenne/fisiopatologia , Necrose , Fenótipo , Regiões Promotoras Genéticas , Proteínas Recombinantes de Fusão/genética , Recuperação de Função Fisiológica , Fatores de Tempo , Fatores de Transcrição/genética , Regulação para Cima , Utrofina/genética , Dedos de Zinco/genéticaRESUMO
Memory consolidation requires gene expression regulation by transcription factors, which eventually may induce chromatin modifications as histone acetylation. This mechanism is regulated by histone acetylases and deacetylases. It is not yet clear whether memory consolidation always recruits histone acetylation or it is only engaged in more persistent memories. To address this question, we used different strength of training for novel object recognition task in mice. Only strong training induced a long-lasting memory and an increase in hippocampal histone H3 acetylation. Histone acetylase inhibition in the hippocampus during consolidation impaired memory persistence, whereas histone deacetylase inhibition caused weak memory to persist. Nuclear factor κB (NF-κB) transcription factor inhibition impaired memory persistence and, concomitantly, reduced the general level of H3 acetylation. Accordingly, we found an important increase in H3 acetylation at a specific NF-κB-regulated promoter region of the Camk2d gene, which was reversed by NF-kB inhibition. These results show for the first time that histone acetylation is a specific molecular signature of enduring memories.
Assuntos
Histonas/metabolismo , Memória/fisiologia , NF-kappa B/fisiologia , Reconhecimento Psicológico/fisiologia , Acetilação , Animais , Histona Acetiltransferases/metabolismo , Aprendizagem/fisiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Duchenne muscular dystrophy (DMD) is the most common X-linked muscle degenerative disease and it is due to the absence of the cytoskeletal protein dystrophin. Currently there is no effective treatment for DMD. Among the different strategies for achieving a functional recovery of the dystrophic muscle, the upregulation of the dystrophin-related gene utrophin is becoming more and more feasible. RESULTS: We have previously shown that the zinc finger-based artificial transcriptional factor "Jazz" corrects the dystrophic pathology in mdx mice by upregulating utrophin gene expression. Here we describe a novel artificial transcription factor, named "UtroUp", engineered to further improve the DNA-binding specificity. UtroUp has been designed to recognise an extended DNA target sequence on both the human and mouse utrophin gene promoters. The UtroUp DNA-binding domain contains six zinc finger motifs in tandem, which is able to recognise an 18-base-pair DNA target sequence that statistically is present only once in the human genome. To achieve a higher transcriptional activation, we coupled the UtroUp DNA-binding domain with the innovative transcriptional activation domain, which was derived from the multivalent adaptor protein Che-1/AATF. We show that the artificial transcription factor UtroUp, due to its six zinc finger tandem motif, possesses a low dissociation constant that is consistent with a strong affinity/specificity toward its DNA-binding site. When expressed in mammalian cell lines, UtroUp promotes utrophin transcription and efficiently accesses active chromatin promoting accumulation of the acetylated form of histone H3 in the utrophin promoter locus. CONCLUSIONS: This novel artificial molecule may represent an improved platform for the development of future applications in DMD treatment.
Assuntos
Distrofia Muscular de Duchenne/metabolismo , Regiões Promotoras Genéticas , Fatores de Transcrição/química , Fatores de Transcrição/metabolismo , Regulação para Cima , Utrofina/genética , Utrofina/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Regulação da Expressão Gênica , Humanos , Camundongos , Distrofia Muscular de Duchenne/genética , Fatores de Transcrição/genética , Utrofina/química , Dedos de ZincoRESUMO
Zinc finger (ZF) proteins belonging to the Cys2-His2 class provide a simple and versatile framework to design novel artificial transcription factors (ATFs) targeted to the desired genes. Our work is based on ZF ATFs engineered to up-regulate the expression level of the dystrophin-related gene utrophin in Duchenne muscular dystrophy (DMD). In particular, on the basis of the "recognition code" that defines specific rules between zinc finger primary structure and potential DNA-binding sites we engineered and selected a new family of artificial transcription factors, whose DNA-binding domain consists in a three zinc finger peptide called "Jazz." Jazz protein binds specifically the 9 bp DNA sequence (5(')-GCT-GCT-GCG-3(')) present in the promoter region of both the human and mouse utrophin gene. We generated a transgenic mouse expressing Jazz protein fused to the strong transcriptional activation domain VP16 and under the control of the muscle specific promoter of the myosin light chain gene. Vp16-Jazz mice display a strong up-regulation of the utrophin at both mRNA and protein levels. To our knowledge, this represents the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger-based transcription factor.
Assuntos
Terapia Genética/métodos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Fatores de Transcrição/metabolismo , Dedos de Zinco/genética , Animais , Western Blotting , Imunoprecipitação da Cromatina , Eletroforese em Gel de Poliacrilamida , Feminino , Genótipo , Humanos , Immunoblotting , Masculino , Camundongos , Camundongos Transgênicos , Fatores de Transcrição/genética , Utrofina/genéticaRESUMO
Here, we show that the eukaryotic translation elongation factor 1 gamma (eEF1γ) physically interacts with the RNA polymerase II (pol II) core subunit 3 (RPB3), both in isolation and in the context of the holo-enzyme. Importantly, eEF1γ has been recently shown to bind Vimentin mRNA. By chromatin immunoprecipitation experiments, we demonstrate, for the first time, that eEF1γ is also physically present on the genomic locus corresponding to the promoter region of human Vimentin gene. The eEF1γ depletion causes the Vimentin protein to be incorrectly compartmentalised and to severely compromise cellular shape and mitochondria localisation. We demonstrate that eEF1γ partially colocalises with the mitochondrial marker Tom20 and that eEF1γ depletion increases mitochondrial superoxide generation as well as the total levels of carbonylated proteins. Finally, we hypothesise that eEF1γ, in addition to its role in translation elongation complex, is involved in regulating Vimentin gene by contacting both pol II and the Vimentin promoter region and then shuttling/nursing the Vimentin mRNA from its gene locus to its appropriate cellular compartment for translation.
Assuntos
Fator 1 de Elongação de Peptídeos/genética , Regiões Promotoras Genéticas , RNA Polimerase II/genética , Vimentina/genética , Carbono/química , Proteínas do Olho/metabolismo , Células HeLa , Humanos , Proteínas de Membrana Transportadoras/metabolismo , Mitocôndrias/metabolismo , Proteínas do Complexo de Importação de Proteína Precursora Mitocondrial , Proteínas Mitocondriais/metabolismo , Fator 1 de Elongação de Peptídeos/metabolismo , Ligação Proteica , Biossíntese de Proteínas , Estrutura Terciária de Proteína , RNA Polimerase II/metabolismo , Receptores de Superfície Celular/metabolismo , Proteínas de Ligação ao Retinol/metabolismo , Superóxidos/metabolismo , Técnicas do Sistema de Duplo-HíbridoRESUMO
The absence of the cytoskeletal protein dystrophin results in Duchenne muscular dystrophy (DMD). The utrophin protein is the best candidate for dystrophin replacement in DMD patients. To obtain therapeutic levels of utrophin expression in dystrophic muscle, we developed an alternative strategy based on the use of artificial zinc finger transcription factors (ZF ATFs). The ZF ATF 'Jazz' was recently engineered and tested in vivo by generating a transgenic mouse specifically expressing Jazz at the muscular level. To validate the ZF ATF technology for DMD treatment we generated a second mouse model by crossing Jazz-transgenic mice with dystrophin-deficient mdx mice. Here, we show that the artificial Jazz protein restores sarcolemmal integrity and prevents the development of the dystrophic disease in mdx mice. This exclusive animal model establishes the notion that utrophin-based therapy for DMD can be efficiently developed using ZF ATF technology and candidates Jazz as a novel therapeutic molecule for DMD therapy.
Assuntos
Distrofia Muscular Animal/terapia , Fatores de Transcrição/genética , Utrofina/genética , Animais , Distrofina/genética , Distrofina/metabolismo , Feminino , Masculino , Camundongos , Camundongos Endogâmicos mdx , Camundongos Transgênicos , Distrofia Muscular Animal/genética , Distrofia Muscular Animal/patologia , Utrofina/metabolismo , Dedos de ZincoRESUMO
BACKGROUND: Aberrant hypermethylation of CpG islands in housekeeping gene promoters and widespread genome hypomethylation are typical events occurring in cancer cells. The molecular mechanisms behind these cancer-related changes in DNA methylation patterns are not well understood. Two questions are particularly important: (i) how are CpG islands protected from methylation in normal cells, and how is this protection compromised in cancer cells, and (ii) how does the genome-wide demethylation in cancer cells occur. The latter question is especially intriguing since so far no DNA demethylase enzyme has been found. METHODOLOGY/PRINCIPAL FINDINGS: Our data show that the absence of ADP-ribose polymers (PARs), caused by ectopic over-expression of poly(ADP-ribose) glycohydrolase (PARG) in L929 mouse fibroblast cells leads to aberrant methylation of the CpG island in the promoter of the Dnmt1 gene, which in turn shuts down its transcription. The transcriptional silencing of Dnmt1 may be responsible for the widespread passive hypomethylation of genomic DNA which we detect on the example of pericentromeric repeat sequences. Chromatin immunoprecipitation results show that in normal cells the Dnmt1 promoter is occupied by poly(ADP-ribosyl)ated Parp1, suggesting that PARylated Parp1 plays a role in protecting the promoter from methylation. CONCLUSIONS/SIGNIFICANCE: In conclusion, the genome methylation pattern following PARG over-expression mirrors the pattern characteristic of cancer cells, supporting our idea that the right balance between Parp/Parg activities maintains the DNA methylation patterns in normal cells. The finding that in normal cells Parp1 and ADP-ribose polymers localize on the Dnmt1 promoter raises the possibility that PARylated Parp1 marks those sequences in the genome that must remain unmethylated and protects them from methylation, thus playing a role in the epigenetic regulation of gene expression.
Assuntos
DNA (Citosina-5-)-Metiltransferases/genética , Metilação de DNA , Epigênese Genética , Poli(ADP-Ribose) Polimerases/metabolismo , Regiões Promotoras Genéticas , Animais , Linhagem Celular , DNA (Citosina-5-)-Metiltransferase 1 , Fibroblastos , Genoma , Glicosídeo Hidrolases/metabolismo , Camundongos , Poli(ADP-Ribose) Polimerase-1 , Poli(ADP-Ribose) Polimerases/genéticaRESUMO
Our aim is to upregulate the expression level of the dystrophin related gene utrophin in Duchenne muscular dystrophy, thus complementing the lack of dystrophin functions. To this end, we have engineered synthetic zinc finger based transcription factors. We have previously shown that the artificial three-zinc finger protein named Jazz fused with the Vp16 activation domain, is able to bind utrophin promoter A and to increase the endogenous level of utrophin in transgenic mice. Here, we report on an innovative artificial protein, named CJ7, that consists of Jazz DNA binding domain fused to a novel activation domain derived from the regulatory multivalent adaptor protein Che-1/AATF. This transcriptional activation domain is 100 amino acids in size and it is very powerful as compared to the Vp16 activation domain. We show that CJ7 protein efficiently promotes transcription and accumulation of the acetylated form of histone H3 on the genomic utrophin promoter locus.