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1.
Cell ; 180(6): 1228-1244.e24, 2020 03 19.
Artigo em Inglês | MEDLINE | ID: mdl-32142649

RESUMO

Transcription-coupled nucleotide excision repair (TC-NER) is initiated by the stalling of elongating RNA polymerase II (RNAPIIo) at DNA lesions. The ubiquitination of RNAPIIo in response to DNA damage is an evolutionarily conserved event, but its function in mammals is unknown. Here, we identified a single DNA damage-induced ubiquitination site in RNAPII at RPB1-K1268, which regulates transcription recovery and DNA damage resistance. Mechanistically, RPB1-K1268 ubiquitination stimulates the association of the core-TFIIH complex with stalled RNAPIIo through a transfer mechanism that also involves UVSSA-K414 ubiquitination. We developed a strand-specific ChIP-seq method, which revealed RPB1-K1268 ubiquitination is important for repair and the resolution of transcriptional bottlenecks at DNA lesions. Finally, RPB1-K1268R knockin mice displayed a short life-span, premature aging, and neurodegeneration. Our results reveal RNAPII ubiquitination provides a two-tier protection mechanism by activating TC-NER and, in parallel, the processing of DNA damage-stalled RNAPIIo, which together prevent prolonged transcription arrest and protect against neurodegeneration.


Assuntos
Reparo do DNA/fisiologia , RNA Polimerase II/metabolismo , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , DNA/metabolismo , Dano ao DNA/fisiologia , DNA Helicases/metabolismo , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Feminino , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , RNA Polimerase II/genética , Ubiquitinação
2.
Mol Cell ; 84(15): 2949-2965.e10, 2024 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-39053456

RESUMO

The eukaryotic nucleus has a highly organized structure. Although the spatiotemporal arrangement of spliceosomes on nascent RNA drives splicing, the nuclear architecture that directly supports this process remains unclear. Here, we show that RNA-binding proteins (RBPs) assembled on RNA form meshworks in human and mouse cells. Core and accessory RBPs in RNA splicing make two distinct meshworks adjacently but distinctly distributed throughout the nucleus. This is achieved by mutual exclusion dynamics between the charged and uncharged intrinsically disordered regions (IDRs) of RBPs. These two types of meshworks compete for spatial occupancy on pre-mRNA to regulate splicing. Furthermore, the optogenetic enhancement of the RBP meshwork causes aberrant splicing, particularly of genes involved in neurodegeneration. Genetic mutations associated with neurodegenerative diseases are often found in the IDRs of RBPs, and cells harboring these mutations exhibit impaired meshwork formation. Our results uncovered the spatial organization of RBP networks to drive RNA splicing.


Assuntos
Núcleo Celular , Splicing de RNA , Proteínas de Ligação a RNA , Humanos , Núcleo Celular/metabolismo , Núcleo Celular/genética , Animais , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , Camundongos , Precursores de RNA/metabolismo , Precursores de RNA/genética , Mutação , Spliceossomos/metabolismo , Spliceossomos/genética , Células HeLa , Células HEK293
3.
Hum Mol Genet ; 32(9): 1511-1523, 2023 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-36579833

RESUMO

At the neuromuscular junction, the downstream of tyrosine kinase 7 (DOK7) enhances the phosphorylation of muscle-specific kinase (MuSK) and induces clustering of acetylcholine receptors (AChRs). We identified a patient with congenital myasthenic syndrome (CMS) with two heteroallelic mutations in DOK7, c.653-1G>C in intron 5 and c.190G>A predicting p.G64R in the pleckstrin homology domain. iPS cells established from the patient (CMS-iPSCs) showed that c.653-1G>C caused in-frame skipping of exon 6 (120 bp) and frame-shifting activation of a cryptic splice site deleting seven nucleotides in exon 6. p.G64R reduced the expression of DOK7 to 10% of wild-type DOK7, and markedly compromised AChR clustering in transfected C2C12 myotubes. p.G64R-DOK7 made insoluble aggresomes at the juxtanuclear region in transfected C2C12 myoblasts and COS7 cells, which were co-localized with molecules in the autophagosome system. A protease inhibitor MG132 reduced the soluble fraction of p.G64R-DOK7 and enhanced the aggresome formation of p.G64R-DOK7. To match the differentiation levels between patient-derived and control induced pluripotent stem cells (iPSCs), we corrected c.190G>A (p.G64R) by CRISPR/Cas9 to make isogenic iPSCs while retaining c.653-1G>C (CMS-iPSCsCas9). Myogenically differentiated CMS-iPSCs showed juxtanuclear aggregates of DOK7, reduced expression of endogenous DOK7 and reduced phosphorylation of endogenous MuSK. Another mutation, p.T77M, also made aggresome to a less extent compared with p.G64R in transfected COS7 cells. These results suggest that p.G64R-DOK7 makes aggresomes in cultured cells and is likely to compromise MuSK phosphorylation for AChR clustering.


Assuntos
Células-Tronco Pluripotentes Induzidas , Síndromes Miastênicas Congênitas , Humanos , Células Cultivadas , Células-Tronco Pluripotentes Induzidas/metabolismo , Proteínas Musculares/genética , Mutação , Síndromes Miastênicas Congênitas/genética , Síndromes Miastênicas Congênitas/metabolismo , Fosforilação , Receptores Colinérgicos/genética , Receptores Colinérgicos/metabolismo
4.
EMBO J ; 40(22): e107485, 2021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34605568

RESUMO

Although large exons cannot be readily recognized by the spliceosome, many are evolutionarily conserved and constitutively spliced for inclusion in the processed transcript. Furthermore, whether large exons may be enriched in a certain subset of proteins, or mediate specific functions, has remained unclear. Here, we identify a set of nearly 3,000 SRSF3-dependent large constitutive exons (S3-LCEs) in human and mouse cells. These exons are enriched for cytidine-rich sequence motifs, which bind and recruit the splicing factors hnRNP K and SRSF3. We find that hnRNP K suppresses S3-LCE splicing, an effect that is mitigated by SRSF3 to thus achieve constitutive splicing of S3-LCEs. S3-LCEs are enriched in genes for components of transcription machineries, including mediator and BAF complexes, and frequently contain intrinsically disordered regions (IDRs). In a subset of analyzed S3-LCE-containing transcription factors, SRSF3 depletion leads to deletion of the IDRs due to S3-LCE exon skipping, thereby disrupting phase-separated assemblies of these factors. Cytidine enrichment in large exons introduces proline/serine codon bias in intrinsically disordered regions and appears to have been evolutionarily acquired in vertebrates. We propose that layered splicing regulation by hnRNP K and SRSF3 ensures proper phase-separation of these S3-LCE-containing transcription factors in vertebrates.


Assuntos
Éxons , Fatores de Processamento de Serina-Arginina/genética , Fatores de Transcrição/genética , Vertebrados/genética , Animais , Linhagem Celular , Citidina/genética , Evolução Molecular , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo K/metabolismo , Humanos , Proteínas Intrinsicamente Desordenadas/genética , Proteínas Intrinsicamente Desordenadas/metabolismo , Camundongos , Poliadenilação , Splicing de RNA , Proteínas de Ligação a RNA/genética , Fatores de Processamento de Serina-Arginina/metabolismo , Fatores de Transcrição/metabolismo
5.
J Neurochem ; 168(4): 342-354, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37994470

RESUMO

Skeletal muscle fiber is a large syncytium with multiple and evenly distributed nuclei. Adult subsynaptic myonuclei beneath the neuromuscular junction (NMJ) express specific genes, the products of which coordinately function in the maintenance of the pre- and post-synaptic regions. However, the gene expression profiles that promote the NMJ formation during embryogenesis remain largely unexplored. We performed single-nucleus RNA sequencing (snRNA-seq) analysis of embryonic and neonatal mouse diaphragms, and found that each myonucleus had a distinct transcriptome pattern during the NMJ formation. Among the previously reported NMJ-constituting genes, Dok7, Chrna1, and Chrnd are specifically expressed in subsynaptic myonuclei at E18.5. In the E18.5 diaphragm, ca. 10.7% of the myonuclei express genes for the NMJ formation (Dok7, Chrna1, and Chrnd) together with four representative ß-catenin regulators (Amotl2, Ptprk, Fam53b, and Tcf7l2). Additionally, the temporal gene expression patterns of these seven genes are synchronized in differentiating C2C12 myoblasts. Amotl2 and Ptprk are expressed in the sarcoplasm, where ß-catenin serves as a structural protein to organize the membrane-anchored NMJ structure. In contrast, Fam53b and Tcf7l2 are expressed in the myonucleus, where ß-catenin serves as a transcriptional coactivator in Wnt/ß-catenin signaling at the NMJ. In C2C12 myotubes, knockdown of Amotl2 or Ptprk markedly, and that of Fam53b and Tcf7l2 less efficiently, impair the clustering of acetylcholine receptors. In contrast, knockdown of Fam53b and Tcf7l2, but not of Amotl2 or Ptprk, impairs the gene expression of Slit2 encoding an axonal attractant for motor neurons, which is required for the maturation of motor nerve terminal. Thus, Amotl2 and Ptprk exert different roles at the NM compared to Fam53b and Tcf7l2. Additionally, Wnt ligands originating from the spinal motor neurons and the perichondrium/chondrocyte are likely to work remotely on the subsynaptic nuclei and the myotendinous junctional nuclei, respectively. We conclude that snRNA-seq analysis of embryonic/neonatal diaphragms reveal a novel coordinated expression profile especially in the Wnt/ß-catenin signaling that regulate the formation of the embryonic NMJ.


Assuntos
Transcriptoma , beta Catenina , Camundongos , Animais , beta Catenina/metabolismo , Junção Neuromuscular/genética , Junção Neuromuscular/metabolismo , Via de Sinalização Wnt/genética , RNA Nuclear Pequeno/metabolismo , Desenvolvimento Embrionário , Músculo Esquelético/metabolismo , Receptores Colinérgicos/metabolismo
6.
Biochem Biophys Res Commun ; 731: 150400, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39024975

RESUMO

Neuromuscular signal transmission is affected in various diseases including myasthenia gravis, congenital myasthenic syndromes, and sarcopenia. We used an ATF2-luciferase system to monitor the phosphorylation of MuSK in HEK293 cells introduced with MUSK and LRP4 cDNAs to find novel chemical compounds that enhanced agrin-mediated acetylcholine receptor (AChR) clustering. Four compounds with similar chemical structures carrying benzene rings and heterocyclic rings increased the luciferase activities 8- to 30-folds, and two of them showed continuously graded dose dependence. The effects were higher than that of disulfiram, a clinically available aldehyde dehydrogenase inhibitor, which we identified to be the most competent preapproved drug to enhance ATF2-luciferase activity in the same assay system. In C2C12 myotubes, all the compounds increased the area, intensity, length, and number of AChR clusters. Three of the four compounds increased the phosphorylation of MuSK, but not of Dok7, JNK. ERK, or p38. Monitoring cell toxicity using the neurite elongation of NSC34 neuronal cells as a surrogate marker showed that all the compounds had no effects on the neurite elongation up to 1 µM. Extensive docking simulation and binding structure prediction of the four compounds with all available human proteins using AutoDock Vina and DiffDock showed that the four compounds were unlikely to directly bind to MuSK or Dok7, and the exact target remained unknown. The identified compounds are expected to serve as a seed to develop a novel therapeutic agent to treat defective NMJ signal transmission.


Assuntos
Fibras Musculares Esqueléticas , Receptores Nicotínicos , Receptores Nicotínicos/genética , Receptores Nicotínicos/metabolismo , Fibras Musculares Esqueléticas/efeitos dos fármacos , Fibras Musculares Esqueléticas/metabolismo , Animais , Camundongos , Linhagem Celular , Humanos , Fator 2 Ativador da Transcrição/genética , Fator 2 Ativador da Transcrição/metabolismo , Genes Reporter , Proteínas Relacionadas a Receptor de LDL/genética , Proteínas Relacionadas a Receptor de LDL/metabolismo , Receptores Proteína Tirosina Quinases/genética , Receptores Proteína Tirosina Quinases/metabolismo , Receptores Colinérgicos/genética , Receptores Colinérgicos/metabolismo , Família Multigênica , Transdução de Sinais/efeitos dos fármacos , Proteínas Musculares/genética , Proteínas Musculares/metabolismo , Neuritos , Bungarotoxinas/farmacologia , Benzeno/farmacologia , Compostos Heterocíclicos/farmacologia , Simulação de Acoplamento Molecular
7.
J Hum Genet ; 69(6): 235-244, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38424183

RESUMO

Dyssegmental dysplasia (DD) is a severe skeletal dysplasia comprised of two subtypes: lethal Silverman-Handmaker type (DDSH) and nonlethal Rolland-Desbuquois type (DDRD). DDSH is caused by biallelic pathogenic variants in HSPG2 encoding perlecan, whereas the genetic cause of DDRD remains undetermined. Schwartz-Jampel syndrome (SJS) is also caused by biallelic pathogenic variants in HSPG2 and is an allelic disorder of DDSH. In SJS and DDSH, 44 and 8 pathogenic variants have been reported in HSPG2, respectively. Here, we report that five patients with DDRD carried four pathogenic variants in HSPG2: c.9970 G > A (p.G3324R), c.559 C > T (p.R187X), c7006 + 1 G > A, and c.11562 + 2 T > G. Two patients were homozygous for p.G3324R, and three patients were heterozygous for p.G3324R. Haplotype analysis revealed a founder haplotype spanning 85,973 bp shared in the five patients. SJS, DDRD, and DDSH are allelic disorders with pathogenic variants in HSPG2.


Assuntos
Haplótipos , Proteoglicanas de Heparan Sulfato , Osteocondrodisplasias , Feminino , Humanos , Masculino , Alelos , Doenças do Desenvolvimento Ósseo/genética , Doenças do Desenvolvimento Ósseo/patologia , Efeito Fundador , Proteoglicanas de Heparan Sulfato/genética , Mutação , Osteocondrodisplasias/genética , Osteocondrodisplasias/patologia , Doenças Fetais
8.
Pituitary ; 26(2): 237-249, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-36995457

RESUMO

PURPOSE: Delayed hyponatremia (DHN), a unique complication, is the leading cause of unexpected readmission after pituitary surgery. Therefore, this study aimed to develop tools for predicting postoperative DHN in patients undergoing endoscopic transsphenoidal surgery (eTSS) for pituitary neuroendocrine tumors (PitNETs). METHODS: This was a single-center, retrospective study involving 193 patients with PitNETs who underwent eTSS. The objective variable was DHN, defined as serum sodium levels < 135 mmol/L at ≥ 1 time between post operative days 3 and 9. We trained four machine learning models to predict this objective variable using the clinical variables available preoperatively and on the first postoperative day. The clinical variables included patient characteristics, pituitary-related hormone levels, blood test results, radiological findings, and postoperative complications. RESULTS: The random forest (RF) model demonstrated the highest (0.759 ± 0.039) area under the curve of the receiver operating characteristic curve (ROC-AUC), followed by the support vector machine (0.747 ± 0.034), the light gradient boosting machine (LGBM: 0.738 ± 0.026), and the logistic regression (0.710 ± 0.028). The highest accuracy (0.746 ± 0.029) was observed in the LGBM model. The best-performing RF model was based on 24 features, nine of which were clinically available preoperatively. CONCLUSIONS: The proposed machine learning models with pre- and post-resection features predicted DHN after the resection of PitNETs.


Assuntos
Adenoma , Hiponatremia , Neoplasias Hipofisárias , Humanos , Hiponatremia/etiologia , Estudos Retrospectivos , Adenoma/cirurgia , Neoplasias Hipofisárias/cirurgia , Neoplasias Hipofisárias/complicações , Aprendizado de Máquina
9.
BMC Musculoskelet Disord ; 24(1): 200, 2023 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-36927417

RESUMO

BACKGROUND: Postmenopausal osteoporosis is a widespread health concern due to its prevalence among older adults and an associated high risk of fracture. The downregulation of bone regeneration delays fracture healing. Activated fibroblast growth factor receptor 3 (FGFR3) accelerates bone regeneration at juvenile age and downregulates bone mineralization at all ages. However, the impact of FGFR3 signaling on bone regeneration and bone mineralization post-menopause is still unknown. This study aimed to evaluate the impact of FGFR3 signaling on bone regeneration and bone mineralization during menopause by developing a distraction osteogenesis (DO) mouse model after ovariectomy (OVX) using transgenic mice with activated FGFR3 driven by Col2a1 promoter (Fgfr3 mice). METHODS: The OVX or sham operations were performed in 8-week-old female Fgfr3 and wild-type mice. After 8 weeks of OVX surgery, DO surgery in the lower limb was performed. The 5-day-latency period followed by performing distraction for 9 days. Bone mineral density (BMD) and bone regeneration was assessed by micro-computed tomography (micro-CT) scan and soft X-ray. Bone volume in the distraction area was also evaluated by histological analysis after 7 days at the end of distraction. Osteogenic differentiation and mineralization of bone marrow-derived mesenchymal stem cells (BMSCs) derived from each mouse after 8 weeks of the OVX or sham operations were also evaluated with and without an inhibitor for FGFR3 signaling (meclozine). RESULTS: BMD decreased after OVX in both groups, and it further deteriorated in Fgfr3 mice. Poor callus formation after DO was also observed in both groups with OVX, and the amount of regenerated bone was further decreased in Fgfr3 mice. Similarly, histological analysis revealed that Fgfr3 OVX mice showed lower bone volume. Osteogenic differentiation and mineralization of BMSCs were also deteriorated in Fgfr3 OVX mice. An inhibitor for FGFR3 signaling dramatically reversed the inhibitory effect of OVX and FGFR3 signaling on BMSC mineralization. CONCLUSION: Upregulated FGFR3 decreased newly regenerated bone after DO and BMD in OVX mice. FGFR3 signaling can be a potential therapeutic target in patients with postmenopausal osteoporosis.


Assuntos
Osteogênese , Osteoporose Pós-Menopausa , Animais , Feminino , Humanos , Camundongos , Densidade Óssea , Regeneração Óssea , Calcificação Fisiológica , Modelos Animais de Doenças , Osteoporose Pós-Menopausa/genética , Osteoporose Pós-Menopausa/patologia , Ovariectomia , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 3 de Fator de Crescimento de Fibroblastos/farmacologia , Microtomografia por Raio-X
10.
Ecotoxicol Environ Saf ; 264: 115482, 2023 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-37717354

RESUMO

The pervasive weak electromagnetic fields (EMF) inundate the industrialized society, but the biological effects of EMF as weak as 10 µT have been scarcely analyzed. Heat shock proteins (HSPs) are molecular chaperones that mediate a sequential stress response. HSP70 and HSP90 provide cells under undesirable situations with either assisting covalent folding of proteins or degrading improperly folded proteins in an ATP-dependent manner. Here we examined the effect of extremely low-frequency (ELF)-EMF on AML12 and HEK293 cells. Although the protein expression levels of HSP70 and HSP90 were reduced after an exposure to ELF-EMF for 3 h, acetylations of HSP70 and HSP90 were increased, which was followed by an enhanced binding affinities of HSP70 and HSP90 for HSP70/HSP90-organizing protein (HOP/STIP1). After 3 h exposure to ELF-EMF, the amount of mitochondria was reduced but the ATP level and the maximal mitochondrial oxygen consumption were increased, which was followed by the reduced protein aggregates and the increased cell viability. Thus, ELF-EMF exposure for 3 h activated acetylation of HSPs to enhance protein folding, which was returned to the basal level at 12 h. The proteostatic effects of ELF-EMF will be able to be applied to treat pathological states in humans.


Assuntos
Campos Eletromagnéticos , Proteínas de Choque Térmico , Humanos , Acetilação , Campos Eletromagnéticos/efeitos adversos , Células HEK293 , Dobramento de Proteína , Proteínas de Choque Térmico HSP70 , Proteínas de Choque Térmico HSP90 , Trifosfato de Adenosina
11.
Genes Dev ; 29(10): 1045-57, 2015 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-25995189

RESUMO

More than half of all human genes produce prematurely terminated polyadenylated short mRNAs. However, the underlying mechanisms remain largely elusive. CLIP-seq (cross-linking immunoprecipitation [CLIP] combined with deep sequencing) of FUS (fused in sarcoma) in neuronal cells showed that FUS is frequently clustered around an alternative polyadenylation (APA) site of nascent RNA. ChIP-seq (chromatin immunoprecipitation [ChIP] combined with deep sequencing) of RNA polymerase II (RNAP II) demonstrated that FUS stalls RNAP II and prematurely terminates transcription. When an APA site is located upstream of an FUS cluster, FUS enhances polyadenylation by recruiting CPSF160 and up-regulates the alternative short transcript. In contrast, when an APA site is located downstream from an FUS cluster, polyadenylation is not activated, and the RNAP II-suppressing effect of FUS leads to down-regulation of the alternative short transcript. CAGE-seq (cap analysis of gene expression [CAGE] combined with deep sequencing) and PolyA-seq (a strand-specific and quantitative method for high-throughput sequencing of 3' ends of polyadenylated transcripts) revealed that position-specific regulation of mRNA lengths by FUS is operational in two-thirds of transcripts in neuronal cells, with enrichment in genes involved in synaptic activities.


Assuntos
Regulação da Expressão Gênica , RNA Mensageiro/metabolismo , Proteína FUS de Ligação a RNA/metabolismo , RNA/metabolismo , Animais , Linhagem Celular Tumoral , Fator de Especificidade de Clivagem e Poliadenilação/metabolismo , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Camundongos , Poliadenilação , Ligação Proteica , RNA Polimerase II/metabolismo , Transcriptoma
12.
Int J Mol Sci ; 24(4)2023 Feb 13.
Artigo em Inglês | MEDLINE | ID: mdl-36835142

RESUMO

Congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders characterized by impaired neuromuscular signal transmission due to germline pathogenic variants in genes expressed at the neuromuscular junction (NMJ). A total of 35 genes have been reported in CMS (AGRN, ALG14, ALG2, CHAT, CHD8, CHRNA1, CHRNB1, CHRND, CHRNE, CHRNG, COL13A1, COLQ, DOK7, DPAGT1, GFPT1, GMPPB, LAMA5, LAMB2, LRP4, MUSK, MYO9A, PLEC, PREPL, PURA, RAPSN, RPH3A, SCN4A, SLC18A3, SLC25A1, SLC5A7, SNAP25, SYT2, TOR1AIP1, UNC13A, VAMP1). The 35 genes can be classified into 14 groups according to the pathomechanical, clinical, and therapeutic features of CMS patients. Measurement of compound muscle action potentials elicited by repetitive nerve stimulation is required to diagnose CMS. Clinical and electrophysiological features are not sufficient to identify a defective molecule, and genetic studies are always required for accurate diagnosis. From a pharmacological point of view, cholinesterase inhibitors are effective in most groups of CMS, but are contraindicated in some groups of CMS. Similarly, ephedrine, salbutamol (albuterol), amifampridine are effective in most but not all groups of CMS. This review extensively covers pathomechanical and clinical features of CMS by citing 442 relevant articles.


Assuntos
Síndromes Miastênicas Congênitas , Simportadores , Humanos , Albuterol , Amifampridina , Inibidores da Colinesterase , Proteínas Mitocondriais/genética , Mutação , Síndromes Miastênicas Congênitas/genética , Síndromes Miastênicas Congênitas/patologia , Canal de Sódio Disparado por Voltagem NAV1.4/genética , Junção Neuromuscular/patologia , Receptores Colinérgicos/genética , Simportadores/genética , Transmissão Sináptica
13.
Int J Mol Sci ; 24(8)2023 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-37108583

RESUMO

Agrin is a heparan sulfate proteoglycan essential for the clustering of acetylcholine receptors at the neuromuscular junction. Neuron-specific isoforms of agrin are generated by alternative inclusion of three exons, called Y, Z8, and Z11 exons, although their processing mechanisms remain elusive. We found, by inspection of splicing cis-elements into the human AGRN gene, that binding sites for polypyrimidine tract binding protein 1 (PTBP1) were extensively enriched around Y and Z exons. PTBP1-silencing enhanced the coordinated inclusion of Y and Z exons in human SH-SY5Y neuronal cells, even though three constitutive exons are flanked by these alternative exons. Deletion analysis using minigenes identified five PTBP1-binding sites with remarkable splicing repression activities around Y and Z exons. Furthermore, artificial tethering experiments indicated that binding of a single PTBP1 molecule to any of these sites represses nearby Y or Z exons as well as the other distal exons. The RRM4 domain of PTBP1, which is required for looping out a target RNA segment, was likely to play a crucial role in the repression. Neuronal differentiation downregulates PTBP1 expression and promotes the coordinated inclusion of Y and Z exons. We propose that the reduction in the PTPB1-RNA network spanning these alternative exons is essential for the generation of the neuron-specific agrin isoforms.


Assuntos
Neuroblastoma , RNA , Humanos , RNA/metabolismo , Agrina/genética , Agrina/metabolismo , Neurônios/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Processamento Alternativo , Proteína de Ligação a Regiões Ricas em Polipirimidinas/genética , Proteína de Ligação a Regiões Ricas em Polipirimidinas/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas/genética , Ribonucleoproteínas Nucleares Heterogêneas/metabolismo
14.
Biochem Biophys Res Commun ; 592: 87-92, 2022 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-35033871

RESUMO

We screened pre-approved drugs for the survival of the Hu5/KD3 human myogenic progenitors. We found that meclozine, an anti-histamine drug that has long been used for motion sickness, promoted the proliferation and survival of Hu5/KD3 cells. Meclozine increased expression of MyoD, but reduced expression of myosin heavy chain and suppressed myotube formation. Withdrawal of meclozine, however, resumed the ability of Hu5/KD3 cells to differentiate into myotubes. We examined the effects of meclozine on mdx mouse carrying a nonsense mutation in the dystrophin gene and modeling for Duchenne muscular dystrophy. Intragastric administration of meclozine in mdx mouse increased the body weight, the muscle mass in the lower limbs, the cross-sectional area of the paravertebral muscle, and improved exercise performances. Previous reports show that inhibition of phosphorylation of ERK1/2 improves muscle functions in mouse models for Emery-Dreifuss muscular dystrophy and cancer cachexia, as well as in mdx mice. We and others previously showed that meclozine blocks the phosphorylation of ERK1/2 in cultured cells. We currently showed that meclozine decreased phosphorylation of ERK1/2 in muscles in mdx mice but not in wild-type mice. This was likely to be one of the underlying mechanisms of the effects of meclozine on mdx mice.


Assuntos
Meclizina/farmacologia , Força Muscular/fisiologia , Músculo Esquelético/patologia , Músculo Esquelético/fisiopatologia , Animais , Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Humanos , Masculino , Meclizina/uso terapêutico , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos mdx , Atividade Motora/efeitos dos fármacos , Desenvolvimento Muscular/efeitos dos fármacos , Força Muscular/efeitos dos fármacos , Distrofia Muscular de Duchenne/tratamento farmacológico , Distrofia Muscular de Duchenne/patologia , Distrofia Muscular de Duchenne/fisiopatologia , Fosforilação/efeitos dos fármacos
15.
EMBO Rep ; 21(5): e49890, 2020 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-32189459

RESUMO

RNA processing occurs co-transcriptionally through the dynamic recruitment of RNA processing factors to RNA polymerase II (RNAPII). However, transcriptome-wide identification of protein-RNA interactions specifically assembled on transcribing RNAPII is challenging. Here, we develop the targeted RNA immunoprecipitation sequencing (tRIP-seq) method that detects protein-RNA interaction sites in thousands of cells. The high sensitivity of tRIP-seq enables identification of protein-RNA interactions at functional subcellular levels. Application of tRIP-seq to the FUS-RNA complex in the RNAPII machinery reveals that FUS binds upstream of alternative polyadenylation (APA) sites of nascent RNA bound to RNAPII, which retards RNAPII and suppresses the recognition of the polyadenylation signal by CPSF. Further tRIP-seq analyses demonstrate that the repression of APA is achieved by a complex composed of FUS and U1 snRNP on RNAPII, but not by either one alone. Moreover, our analysis reveals that FUS mutations in familial amyotrophic lateral sclerosis (ALS) that impair the FUS-U1 snRNP interaction aberrantly activate the APA sites. tRIP-seq provides new insights into the regulatory mechanism of co-transcriptional RNA processing by RNA processing factors.


Assuntos
Poliadenilação , Proteína FUS de Ligação a RNA , Ribonucleoproteína Nuclear Pequena U1 , Humanos , RNA/metabolismo , RNA Polimerase II/genética , RNA Polimerase II/metabolismo , Proteína FUS de Ligação a RNA/genética , Proteína FUS de Ligação a RNA/metabolismo , Ribonucleoproteína Nuclear Pequena U1/genética , Ribonucleoproteína Nuclear Pequena U1/metabolismo
16.
EMBO Rep ; 21(8): e48462, 2020 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-32558157

RESUMO

At the neuromuscular junction (NMJ), lipoprotein-related receptor 4 (LRP4) mediates agrin-induced MuSK phosphorylation that leads to clustering of acetylcholine receptors (AChRs) in the postsynaptic region of the skeletal muscle. Additionally, the ectodomain of LRP4 is necessary for differentiation of the presynaptic nerve terminal. However, the molecules regulating LRP4 have not been fully elucidated yet. Here, we show that the CT domain of connective tissue growth factor (CTGF/CCN2) directly binds to the third beta-propeller domain of LRP4. CTGF/CCN2 enhances the binding of LRP4 to MuSK and facilitates the localization of LRP4 on the plasma membrane. CTGF/CCN2 enhances agrin-induced MuSK phosphorylation and AChR clustering in cultured myotubes. Ctgf-deficient mouse embryos (Ctgf-/- ) have small AChR clusters and abnormal dispersion of synaptic vesicles along the motor axon. Ultrastructurally, the presynaptic nerve terminals have reduced numbers of active zones and mitochondria. Functionally, Ctgf-/- embryos exhibit impaired NMJ signal transmission. These results indicate that CTGF/CCN2 interacts with LRP4 to facilitate clustering of AChRs at the motor endplate and the maturation of the nerve terminal.


Assuntos
Fator de Crescimento do Tecido Conjuntivo , Proteínas Relacionadas a Receptor de LDL , Agrina/genética , Agrina/metabolismo , Animais , Fator de Crescimento do Tecido Conjuntivo/genética , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Proteínas Relacionadas a Receptor de LDL/genética , Proteínas Relacionadas a Receptor de LDL/metabolismo , Camundongos , Junção Neuromuscular/metabolismo , Fosforilação
17.
Int J Mol Sci ; 23(23)2022 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-36498838

RESUMO

Many studies demonstrate the safety of alkaline-electrolyzed-reduced water (ERW); however, several animal studies have reported significant tissue damage and hyperkalemia after drinking ERW. The mechanism responsible for these results remains unknown but may be due to electrode degradation associated with the production of higher pH, in which platinum nanoparticles and other metals that have harmful effects may leach into the water. Clinical studies have reported that, when ERW exceeds pH 9.8, some people develop dangerous hyperkalemia. Accordingly, regulations on ERW mandate that the pH of ERW should not exceed 9.8. It is recommended that those with impaired kidney function refrain from using ERW without medical supervision. Other potential safety concerns include impaired growth, reduced mineral, vitamin, and nutrient absorption, harmful bacterial overgrowth, and damage to the mucosal lining causing excessive thirst. Since the concentration of H2 in ERW may be well below therapeutic levels, users are encouraged to frequently measure the H2 concentration with accurate methods, avoiding ORP or ORP-based H2 meters. Importantly, although, there have been many people that have used high-pH ERW without any issues, additional safety research on ERW is warranted, and ERW users should follow recommendations to not ingest ERW above 9.8 pH.


Assuntos
Nanopartículas Metálicas , Água , Animais , Eletrólise , Hidrogênio , Platina , Concentração de Íons de Hidrogênio , Oxirredução
18.
Int J Mol Sci ; 23(23)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36499079

RESUMO

Numerous benefits have been attributed to alkaline-electrolyzed-reduced water (ERW). Sometimes these claims are associated with easily debunked concepts. The observed benefits have been conjectured to be due to the intrinsic properties of ERW (e.g., negative oxidation-reduction potential (ORP), alkaline pH, H2 gas), as well enigmatic characteristics (e.g., altered water structure, microclusters, free electrons, active hydrogen, mineral hydrides). The associated pseudoscientific marketing has contributed to the reluctance of mainstream science to accept ERW as having biological effects. Finally, through many in vitro and in vivo studies, each one of these propositions was examined and refuted one-by-one until it was conclusively demonstrated that H2 was the exclusive agent responsible for both the negative ORP and the observed therapeutic effects of ERW. This article briefly apprised the history of ERW and comprehensively reviewed the sequential research demonstrating the importance of H2. We illustrated that the effects of ERW could be readily explained by the known biological effects of H2 and by utilizing conventional chemistry without requiring any metaphysical conjecture (e.g., microclustering, free electrons, etc.) or reliance on implausible notions (e.g., alkaline water neutralizes acidic waste). The H2 concentration of ERW should be measured to ensure it is comparable to those used in clinical studies.


Assuntos
Eletrólise , Água , Água/química , Hidrogênio/uso terapêutico , Hidrogênio/farmacologia , Concentração de Íons de Hidrogênio
19.
Int J Mol Sci ; 23(8)2022 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-35456905

RESUMO

KIAA1199 has a strong hyaluronidase activity in inflammatory arthritis. This study aimed to identify a drug that could reduce KIAA1199 activity and clarify its effects on inflammatory arthritis. Rat chondrosarcoma (RCS) cells were strongly stained with Alcian blue (AB). Its stainability was reduced in RCS cells, which were over-expressed with the KIAA1199 gene (RCS-KIAA). We screened the drugs that restore the AB stainability in RCS-KIAA. The effects of the drug were evaluated by particle exclusion assay, HA ELISA, RT-PCR, and Western blotting. We further evaluated the HA accumulation and the MMP1 and three expressions in fibroblast-like synoviocytes (FLS). In vivo, the effects of the drug on symptoms and serum concentration of HA in a collagen-induced arthritis mouse were evaluated. Ipriflavone was identified to restore AB stainability at 23%. Extracellular matrix formation was significantly increased in a dose-dependent manner (p = 0.006). Ipriflavone increased the HA accumulation and suppressed the MMP1 and MMP3 expression on TNF-α stimulated FLS. In vivo, Ipriflavone significantly improved the symptoms and reduced the serum concentrations of HA. Conclusions: We identified Ipriflavone, which has inhibitory effects on KIAA1199 activity. Ipriflavone may be a therapeutic candidate based on its reduction of KIAA1199 activity in inflammatory arthritis.


Assuntos
Artrite Experimental , Sinoviócitos , Animais , Artrite Experimental/tratamento farmacológico , Artrite Experimental/metabolismo , Reposicionamento de Medicamentos , Fibroblastos/metabolismo , Ácido Hialurônico/farmacologia , Hialuronoglucosaminidase/metabolismo , Isoflavonas , Metaloproteinase 1 da Matriz/genética , Metaloproteinase 1 da Matriz/metabolismo , Camundongos , Ratos , Sinoviócitos/metabolismo
20.
Int J Mol Sci ; 23(5)2022 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-35270030

RESUMO

Molecular hydrogen ameliorates pathological states in a variety of human diseases, animal models, and cell models, but the effects of hydrogen on cancer have been rarely reported. In addition, the molecular mechanisms underlying the effects of hydrogen remain mostly unelucidated. We found that hydrogen enhances proliferation of four out of seven human cancer cell lines (the responders). The proliferation-promoting effects were not correlated with basal levels of cellular reactive oxygen species. Expression profiling of the seven cells showed that the responders have higher gene expression of mitochondrial electron transport chain (ETC) molecules than the non-responders. In addition, the responders have higher mitochondrial mass, higher mitochondrial superoxide, higher mitochondrial membrane potential, and higher mitochondrial spare respiratory capacity than the non-responders. In the responders, hydrogen provoked mitochondrial unfolded protein response (mtUPR). Suppression of cell proliferation by rotenone, an inhibitor of mitochondrial ETC complex I, was rescued by hydrogen in the responders. Hydrogen triggers mtUPR and induces cell proliferation in cancer cells that have high basal and spare mitochondrial ETC activities.


Assuntos
Neoplasias , Resposta a Proteínas não Dobradas , Animais , Proliferação de Células , Hidrogênio/metabolismo , Hidrogênio/farmacologia , Mitocôndrias/metabolismo , Neoplasias/tratamento farmacológico , Neoplasias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Superóxidos/metabolismo
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