RESUMO
While ultraviolet (UV) radiation damages DNA, eliciting the DNA damage response (DDR), it also damages RNA, triggering transcriptome-wide ribosomal collisions and eliciting a ribotoxic stress response (RSR). However, the relative contributions, timing, and regulation of these pathways in determining cell fate is unclear. Here we use time-resolved phosphoproteomic, chemical-genetic, single-cell imaging, and biochemical approaches to create a chronological atlas of signaling events activated in cells responding to UV damage. We discover that UV-induced apoptosis is mediated by the RSR kinase ZAK and not through the DDR. We identify two negative-feedback modules that regulate ZAK-mediated apoptosis: (1) GCN2 activation limits ribosomal collisions and attenuates ZAK-mediated RSR and (2) ZAK activity leads to phosphodegron autophosphorylation and its subsequent degradation. These events tune ZAK's activity to collision levels to establish regimes of homeostasis, tolerance, and death, revealing its key role as the cellular sentinel for nucleic acid damage.
Assuntos
Apoptose , Dano ao DNA , Raios Ultravioleta , Raios Ultravioleta/efeitos adversos , Apoptose/efeitos da radiação , Fosforilação/efeitos da radiação , Humanos , Transdução de Sinais/efeitos da radiação , Proteínas Serina-Treonina Quinases/metabolismo , Estresse Fisiológico/efeitos da radiação , Ribossomos/metabolismo , Morte Celular/efeitos da radiaçãoRESUMO
Giant axonal neuropathy (GAN) is caused by mutations in the GAN gene encoding for gigaxonin (GIG), which functions as an adaptor of the CUL3-RBX1-GIG (CRL3GIG) E3 ubiquitin ligase complex. The pathological hallmark of GAN is characterized by the accumulation of densely packed neurofilaments (NFs) in the axons. However, there are fundamental knowledge gaps in our understanding of the molecular mechanisms by which the ubiquitin-proteasome system controls the homeostasis of NF proteins. Recently, the deubiquitylating enzyme USP15 was reported to play a crucial role in regulating ubiquitylation and proteasomal degradation of CRL4CRBN substrate proteins. Here, we report that the CRL3GIG-USP15 pathway governs the destruction of NF proteins NEFL and INA. We identified a specific degron called NEFLL12 degron for CRL3GIG. Notably, mutations in the C-terminal Kelch domain of GIG, represented by L309R, R545C, and C570Y, disrupted the binding of GIG to NEFL and INA, leading to the accumulation of these NF proteins. This accounts for the loss-of-function mutations in GAN patients. In addition to regulating NFs, CRL3GIG also controls actin filaments by directly targeting actin-filament-binding regulatory proteins TPM1, TPM2, TAGLN, and CNN2 for proteasomal degradation. Thus, our findings broadly impact the field by providing fundamental mechanistic insights into regulating extremely long-lived NF proteins NEFL and INA by the CRL3GIG-USP15 pathway and offering previously unexplored therapeutic opportunities to treat GAN patients and other neurodegenerative diseases by explicitly targeting downstream substrates of CRL3GIG.
Assuntos
Neuropatia Axonal Gigante , Proteínas de Neurofilamentos , Humanos , Proteínas do Citoesqueleto/metabolismo , Ubiquitina , Ligases , Axônios/metabolismo , Neuropatia Axonal Gigante/genética , Neuropatia Axonal Gigante/patologia , Neuropatia Axonal Gigante/terapia , Proteases Específicas de UbiquitinaRESUMO
Even though neurons are post-mitotic cells, they still engage in protein synthesis to uphold their cellular content balance, including for organelles, such as the endoplasmic reticulum or mitochondria. Additionally, they expend significant energy on tasks like neurotransmitter production and maintaining redox homeostasis. This cellular homeostasis is upheld through a delicate interplay between mRNA transcription-translation and protein degradative pathways, such as autophagy and proteasome degradation. When faced with cues such as nutrient stress, neurons must adapt by altering their proteome to survive. However, in many neurodegenerative disorders, such as Parkinson's disease, the pathway and processes for coping with cellular stress are impaired. This review explores neuronal proteome adaptation in response to cellular stress, such as nutrient stress, with a focus on proteins associated with autophagy, stress response pathways, and neurotransmitters.
Assuntos
Neurônios , Proteostase , Animais , Humanos , Autofagia/fisiologia , Neurônios/metabolismo , Proteoma/metabolismo , Estresse FisiológicoRESUMO
S6K1 has been implicated in a number of key metabolic responses, which contribute to obesity. Critical among these is the control of a transcriptional program required for the commitment of mesenchymal stem cells to the adipocytic lineage. However, in contrast to its role in the cytosol, the functions and targets of nuclear S6K1 are unknown. Here, we show that adipogenic stimuli trigger nuclear translocation of S6K1, leading to H2BS36 phosphorylation and recruitment of EZH2 to H3, which mediates H3K27 trimethylation. This blocks Wnt gene expression, inducing the upregulation of PPARγ and Cebpa and driving increased adipogenesis. Consistent with this finding, white adipose tissue from S6K1-deficient mice exhibits no detectable H2BS36 phosphorylation or H3K27 trimethylation, whereas both responses are highly elevated in obese humans or in mice fed a high-fat diet. These findings define an S6K1-dependent mechanism in early adipogenesis, contributing to the promotion of obesity.
Assuntos
Adipócitos/enzimologia , Adipogenia , Tecido Adiposo/enzimologia , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Histonas/metabolismo , Obesidade/enzimologia , Processamento de Proteína Pós-Traducional , Proteínas Quinases S6 Ribossômicas 70-kDa/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Tecido Adiposo/patologia , Adiposidade , Animais , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Modelos Animais de Doenças , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Epigênese Genética , Células HeLa , Histonas/genética , Humanos , Masculino , Metilação , Camundongos , Obesidade/genética , Obesidade/patologia , PPAR gama/genética , PPAR gama/metabolismo , Fosforilação , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Proteínas Quinases S6 Ribossômicas 90-kDa/genética , Transcrição Gênica , Transfecção , Proteínas Wnt/genética , Proteínas Wnt/metabolismo , Via de Sinalização WntRESUMO
Human pluripotent stem cells (PSCs) have become popular tools within the research community to study developmental and model diseases. While many induced-PSCs (iPSCs) from various genetic background sources are currently available, scientific advancement has been hampered by the considerable phenotypic variations observed between different iPSC lines. A recent collaborative effort selected a novel iPSC line to address this and encourage the adoption of a standardized iPSC line termed KOLF2.1J. Here, leveraging the multiplexing power of isobaric labeling, we systematically investigate, at the 10k proteome level, the relative protein abundance profiles of the KOLF2.1J reference iPSC line upon two distinct cell state differentiation trajectories. In addition, we side-by-side systematically compare this line with the H9 line, an established embryonically derived PSC line that we previously characterized. We noticed differences in the basal proteome of the two cell lines and highlighted the differentially expressed proteins. While the difference between the cell line's proteome subsisted upon differentiation, the global proteome remodeling trajectory was highly similar during the tested differentiation routes. We thus conclude that the KOLF2.1J line performs well at the proteome level upon the neuro and cardiomyogenesis differentiation protocol used. We believe this dataset will serve as a resource of value for the research community.
Assuntos
Células-Tronco Pluripotentes Induzidas , Células-Tronco Pluripotentes , Humanos , Proteoma/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Células-Tronco Pluripotentes/metabolismo , Neurogênese , Linhagem Celular , Diferenciação Celular/genéticaRESUMO
Extensive epigenetic remodeling occurs during the cell fate determination of stem cells. Previously, we discovered that eudesmin regulates lineage commitment of mesenchymal stem cells through the inhibition of signaling molecules. However, the epigenetic modulations upon eudesmin treatment in genomewide level have not been analyzed. Here, we present a transcriptome profiling data showing the enrichment in PRC2 target genes by eudesmin treatment. Furthermore, gene ontology analysis showed that PRC2 target genes downregulated by eudesmin are closely related to Wnt signaling and pluripotency. We selected DKK1 as an eudesmin-dependent potential top hub gene in the Wnt signaling and pluripotency. Through the ChIP-qPCR and RT-qPCR, we found that eudesmin treatment increased the occupancy of PRC2 components, EZH2 and SUZ12, and H3K27me3 level on the promoter region of DKK1, downregulating its transcription level. According to the analysis of GEO profiles, DEGs by depletion of Oct4 showed an opposite pattern to DEGs by eudesmin treatment. Indeed, the expression of pluripotency markers, Oct4, Sox2, and Nanog, was upregulated upon eudesmin treatment. This finding demonstrates that pharmacological modulation of PRC2 dynamics by eudesmin might control Wnt signaling and maintain pluripotency of stem cells.
Assuntos
Furanos , Lignanas , Transcriptoma , Diferenciação Celular , Linhagem Celular , Reposicionamento de Medicamentos , Histonas/metabolismo , Fator 3 de Transcrição de Octâmero , Complexo Repressor Polycomb 2 , Via de Sinalização WntRESUMO
Two-spotted cricket Gryllus bimaculatus is one of many cricket species, and it is widely used as a food source for insectivorous animals. Moreover, this species is one of the edible insects approved by the Korea Food and Drug Administration (KFDA). (±)-Kituramides A (1) and B (2), which are pairs of novel enantiomeric dopamine dimers possessing a formamide group, were isolated from the two-spotted cricket, together with four other known biosynthetically related compounds (3-6). The chemical structures of 1 and 2 were elucidated using a combination of 1D and 2D NMR spectroscopic experiments and HR-ESIMS data. Compounds 1 and 2 were identified as racemic mixtures; the enantiomers (+)-1/2 and (-)-1/2 were successfully separated by utilizing a chiral HPLC column. The absolute configurations of (±)-1 and (±)-2 were unambiguously delineated by the application of quantum chemical ECD calculations. Further, these insect-derived substances were evaluated to understand their effects on cytokine expression in adipocytes. Treatment with (-)-1, (+)-2, and (-)-2 during adipocyte differentiation significantly promoted the expression of Leptin and IL-6, which resembles the actions of dopamine.
Assuntos
Dopamina/análogos & derivados , Gryllidae/metabolismo , Animais , Cromatografia Líquida de Alta Pressão/métodos , Dimerização , Dopamina/química , Estrutura Molecular , EstereoisomerismoRESUMO
Obesity causes a wide range of metabolic diseases including diabetes, cardiovascular disease, and kidney disease. Thus, plenty of studies have attempted to discover naturally derived compounds displaying anti-obesity effects. In this study, we evaluated the inhibitory effects of morolic acid 3-O-caffeate (MAOC), extracted from Betula schmidtii, on adipogenesis. Treatment of 3T3-L1 cells with MAOC during adipogenesis significantly reduced lipid accumulation and decreased the expression of adiponectin, a marker of mature adipocytes. Moreover, the treatment with MAOC only during the early phase (day 0-2) sufficiently inhibited adipogenesis, comparable with the inhibitory effects observed following MAOC treatment during the whole processes of adipogenesis. In the early phase of adipogenesis, the expression level of Wnt6, which inhibits adipogenesis, increased by MAOC treatment in 3T3-L1 cells. To identify the gene regulatory mechanism, we assessed alterations in histone modifications upon MAOC treatment. Both global and local levels on the Wnt6 promoter region of histone H3 lysine 4 trimethylation, an active transcriptional histone marker, increased markedly by MAOC treatment in 3T3-L1 cells. Our findings identified an epigenetic event associated with inhibition of adipocyte generation by MAOC, suggesting its potential as an efficient therapeutic compound to cure obesity and metabolic diseases.
Assuntos
Adipogenia/efeitos dos fármacos , Adipogenia/genética , Epigênese Genética/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Triterpenos/química , Triterpenos/farmacologia , Células 3T3-L1 , Adipócitos/efeitos dos fármacos , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Camundongos , Estrutura Molecular , Proteínas Proto-Oncogênicas/genética , Proteínas Wnt/genéticaRESUMO
Brown adipocytes are characterized by a high number of uncoupling protein 1 (UCP1)-positive mitochondrial content and increased thermogenic capacity. As UCP1-enriched cells can consume lipids by generating heat, browning of white adipocytes is now highlighted as a promising approach for the prevention of obesity and obesity-associated metabolic diseases. Upon cold exposure or ß-adrenergic stimuli, downregulation of microRNA-133 (miR-133) elevates the expression levels of PR domain containing 16 (Prdm16), which has been shown to be a brown adipose determination factor, in brown adipose tissue and subcutaneous white adipose tissues (WAT). Here, we show that treatment of reversine to white adipocytes induces browning via suppression of miR-133a. Reversine treatment promoted the expression of brown adipocyte marker genes, such as Prdm16 and UCP1, increasing the mitochondrial content, while decreasing the levels of miR-133a and white adipocyte marker genes. Ectopic expression of miR-133a mimic reversed the browning effects of the reversine treatment. Moreover, intraperitoneal administration of reversine in mice upregulated thermogenesis and resulted in resistance to high-fat diet-mediated weight gain as well as browning of subcutaneous and epididymal WAT. Taken together, we found a novel way to promote browning of white adipocytes through downregulation of miR-133a followed by activation of Prdm16, with a synthetic chemical, reversine.
Assuntos
Adipócitos Brancos/efeitos dos fármacos , Tecido Adiposo Marrom/efeitos dos fármacos , Fármacos Antiobesidade/farmacologia , MicroRNAs/metabolismo , Morfolinas/farmacologia , Obesidade/prevenção & controle , Purinas/farmacologia , Aumento de Peso/efeitos dos fármacos , Células 3T3-L1 , Adipócitos Brancos/metabolismo , Adipócitos Brancos/patologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Marrom/patologia , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Dieta Hiperlipídica , Modelos Animais de Doenças , Regulação para Baixo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , MicroRNAs/genética , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Obesidade/etiologia , Obesidade/metabolismo , Obesidade/patologia , Fenótipo , Transdução de Sinais , Termogênese/efeitos dos fármacos , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismoRESUMO
BACKGROUND: The mTOR/S6K1 signaling pathway is often activated in cervical cancer, and thus considered a molecular target for cervical cancer therapies. Inhibiting mTOR is cytotoxic to cervical cancer cells and creates a synergistic anti-tumor effect with conventional chemotherapy agents. In this study, we identified a novel S6K1 inhibitor, rosmarinic acid methyl ester (RAME) for the use of therapeutic agent against cervical cancer. METHODS: Combined structure- and ligand-based virtual screening was employed to identify novel S6K1 inhibitors among the in house natural product library. In vitro kinase assay and immunoblot assay was used to examine the effects of RAME on S6K1 signaling pathway. Lipidation of LC3 and mRNA levels of ATG genes were observed to investigate RAME-mediated autophagy. PARP cleavage, mRNA levels of apoptotic genes, and cell survival was measured to examine RAME-mediated apoptosis. RESULTS: RAME was identified as a novel S6K1 inhibitor through the virtual screening. RAME, not rosmarinic acid, effectively reduced mTOR-mediated S6K1 activation and the kinase activity of S6K1 by blocking the interaction between S6K1 and mTOR. Treatment of cervical cancer cells with RAME promoted autophagy and apoptosis, decreasing cell survival rate. Furthermore, we observed that combination treatment with RAME and cisplatin greatly enhanced the anti-tumor effect in cisplatin-resistant cervical cancer cells, which was likely due to mTOR/S6K1 inhibition-mediated autophagy and apoptosis. CONCLUSIONS: Our findings suggest that inhibition of S6K1 by RAME can induce autophagy and apoptosis in cervical cancer cells, and provide a potential option for cervical cancer treatment, particularly when combined with cisplatin.
Assuntos
Antineoplásicos/farmacologia , Cinamatos/farmacologia , Depsídeos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases S6 Ribossômicas 70-kDa/antagonistas & inibidores , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cinamatos/química , Cisplatino/farmacologia , Depsídeos/química , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Técnicas de Silenciamento de Genes , Humanos , Conformação Molecular , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica , Inibidores de Proteínas Quinases/química , Proteínas Quinases S6 Ribossômicas 70-kDa/química , Proteínas Quinases S6 Ribossômicas 70-kDa/genética , Bibliotecas de Moléculas Pequenas , Relação Estrutura-Atividade , Neoplasias do Colo do ÚteroRESUMO
Amanita pantherina is a poisonous mushroom that causes muscle cramps, insanity, and audiovisual disorders. As part of our systematic study on Korean mushrooms, a chemical investigation of A. pantherina fruiting bodies resulted in the isolation and structural identification of three new fatty acid derivatives, pantheric acids A-C (1-3), and a known compound, 1,10-dimethyl ester-2-decenedioic acid (4). Although 1,10-dimethyl ester-2-decenedioic acid (4) was previously reported as a synthetic product, it was structurally identified from a natural source for the first time. The structures of the new compounds were established by detailed analysis of 1D and 2D (1H-1H COSY, HSQC, and HMBC) NMR, HRMS, and LC/MS/MS data. The absolute configurations of compounds 1 and 2 were unambiguously determined by a recently developed method using competing enantioselective acylation coupled with LC/MS analysis. The isolated compounds (1-4) were evaluated for their effects on lipid accumulation during adipocyte maturation. Pantheric acids A-C (1-3) promoted the enlargement of lipid droplets in 3T3-L1 adipocytes and altered lipid metabolism by inducing lipogenesis and inhibiting lipolysis. Our findings provide experimental evidence suggesting the potential adverse effects of pantheric acids A-C from a poisonous mushroom on lipid metabolism.
Assuntos
Adipócitos/efeitos dos fármacos , Amanita/química , Metabolismo dos Lipídeos/efeitos dos fármacos , Células 3T3-L1 , Adipócitos/metabolismo , Animais , Camundongos , Estrutura Molecular , Análise Espectral/métodosRESUMO
The failure of insulin production by pancreatic ß cells is a common hallmark of type 1 diabetes mellitus (T1DM). Because administration of exogenous insulin is associated with diabetes-derived complications, endogenous α to ß cell transition can be an attractive alternative. Although decreased ß cell size and hypoinsulinaemia have been observed in S6K1-deficient mice, the molecular mechanism underlying the involvement of S6K1 in the transcriptional regulation of insulin remains elusive. Here, we show that the hypoinsulinaemic phenotype of S6K1-deficient mice stems from the dysregulated transcription of a set of genes required for insulin and glucagon production. First, we observed that increased expression of α cell marker genes and decreased expression of ß cell marker genes in pancreas tissues from S6K1-deficient mice. Furthermore, S6K1 was highly activated in murine ß cell line, ßTC6, compared to murine α cell line αTC1. In both α and ß cells, active S6K1 promoted the transcription of ß cell marker genes, including insulin, whereas S6K1 inhibition increased the transcription of α cell marker genes. Moreover, S6K1 mediated pancreatic gene regulation by modifying two histone marks (activating H3K4me3 and repressing H3K27me3) on gene promoters. These results suggest that S6K1 drives the α to ß transition through the epigenetic regulation of cell-specific genes, including insulin and glucagon. This novel role of S6K1 in islet cells provides basic clues to establish therapeutic strategies against T1DM.
Assuntos
Antígenos de Diferenciação/biossíntese , Epigênese Genética , Células Secretoras de Glucagon/metabolismo , Células Secretoras de Insulina/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Transcrição Gênica , Animais , Antígenos de Diferenciação/genética , Células Secretoras de Glucagon/citologia , Células Secretoras de Insulina/citologia , Camundongos , Camundongos Mutantes , Proteínas Quinases S6 Ribossômicas 90-kDa/genéticaRESUMO
Eudesmin has been reported to possess diverse therapeutic effects, including anti-tumor, anti-inflammatory, and anti-bacterial activities. However, its molecular action has not been implicated in metabolic disease. In this study, we show that treatment of mesenchymal stem cells (MSCs) with eudesmin disturbs adipogenesis via suppression of S6K1 signaling pathway. Eudesmin treatment inhibited activation and nuclear translocation of S6K1. Consequently, S6K1-mediated phosphorylation of H2B at serine 36 (H2BS36p) was reduced upon eudesmin treatment, further inducing the expression of Wnt6, Wnt10a, and Wnt10b, which disturbed adipogenic differentiation. Moreover, eudesmin promoted myogenic and osteogenic gene expression in MSCs. Taken together, we found a novel small molecule, eudesmin, to block adipogenesis through down-regulation of S6K1-H2BS36p axis, followed by regulation of cell fate determination genes. This study suggests a promising therapeutic approach with eudesmin to cure obesity and metabolic diseases.
Assuntos
Adipogenia/efeitos dos fármacos , Furanos/farmacologia , Lignanas/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Quinases S6 Ribossômicas 90-kDa/antagonistas & inibidores , Transporte Ativo do Núcleo Celular/efeitos dos fármacos , Animais , Linhagem Celular , Expressão Gênica/efeitos dos fármacos , Histonas/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Camundongos , Células Musculares/citologia , Células Musculares/efeitos dos fármacos , Células Musculares/metabolismo , Osteoblastos/citologia , Osteoblastos/efeitos dos fármacos , Osteoblastos/metabolismo , Proteínas Quinases S6 Ribossômicas 90-kDa/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Wnt/genéticaRESUMO
Reversine has been shown to induce dedifferentiation of C2C12 murine myoblasts into multipotent progenitor cells. However, little is known about the key regulators mediating the dedifferentiation induced by reversine. Here, we show that large scale miRNA gene expression profiling of reversine-treated C2C12 myoblasts identifies a down-regulated miRNA, miR-133a, involved in dedifferentiation of myoblasts. Reversine treatment results in up- and down-regulated miRNA profiles. Among miRNAs affected by reversine, the level of muscle-specific miR-133a, which has been shown to be up-regulated during muscle development and to suppress differentiation into other lineages, is markedly reduced by treatment of C2C12 myoblasts with reversine. In parallel, reversine decreases the expression and recruitment of myogenic factor, SRF, to the enhancer regions of miR-133a. Sequentially, down-regulation of miR-133a by reversine is accompanied by a decrease in active histone modifications including trimethylation of histone H3K4 and H3K36, phosphorylation of H3S10, and acetylation of H3K14 on the miR-133a promoter, leading to dissociation of RNA polymerase II from the promoter. Furthermore, inhibition of miR-133a by transfection of C2C12 myoblasts with miR-133a inhibitor increases the expression of osteogenic lineage marker, Ogn, and adipotenic lineage marker, ApoE, similar to that in response to reversine. In contrast, the co-overexpression of miR-133a mimic reversed the effect of reversine on C2C12 myoblast dedifferentiation. Taken together, the results indicate that reversine induces a multipotency of C2C12 myoblasts by suppression of miR-133a expression through depletion of active histone modifications, and suggest that miR-133a is a potential miRNA regulating the reversine-induced dedifferentiation. Collectively, our findings provide a mechanistic rationale for the application of reversine to dedifferentiation of somatic cells.
Assuntos
Epigênese Genética/efeitos dos fármacos , Inativação Gênica/efeitos dos fármacos , MicroRNAs/genética , Morfolinas/farmacologia , Células-Tronco Multipotentes/efeitos dos fármacos , Purinas/farmacologia , Acetilação/efeitos dos fármacos , Animais , Western Blotting , Desdiferenciação Celular/efeitos dos fármacos , Desdiferenciação Celular/genética , Linhagem Celular , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/genética , Perfilação da Expressão Gênica , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Metilação/efeitos dos fármacos , Camundongos , Células-Tronco Multipotentes/metabolismo , Mioblastos/citologia , Mioblastos/efeitos dos fármacos , Mioblastos/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Fosforilação/efeitos dos fármacos , Regiões Promotoras Genéticas/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fator de Resposta Sérica/genética , Fator de Resposta Sérica/metabolismoRESUMO
Subcellular location and activation of Tank Binding Kinase 1 (TBK1) govern precise progression through mitosis. Either loss of activated TBK1 or its sequestration from the centrosomes causes errors in mitosis and growth defects. Yet, what regulates its recruitment and activation on the centrosomes is unknown. We identified that NAK-associated protein 1 (NAP1) is essential for mitosis, binding to and activating TBK1, which both localize to centrosomes. Loss of NAP1 causes several mitotic and cytokinetic defects due to inactivation of TBK1. Our quantitative phosphoproteomics identified numerous TBK1 substrates that are not only confined to the centrosomes but are also associated with microtubules. Substrate motifs analysis indicates that TBK1 acts upstream of other essential cell cycle kinases like Aurora and PAK kinases. We also identified NAP1 as a TBK1 substrate phosphorylating NAP1 at S318 to promote its degradation by the ubiquitin proteasomal system. These data uncover an important distinct function for the NAP1-TBK1 complex during cell division.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Citocinese , Mitose , Proteínas Serina-Treonina Quinases , Humanos , Ciclo Celular , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismoRESUMO
Accumulation of advanced glycation end products (AGEs) on biopolymers accompanies cellular aging and drives poorly understood disease processes. Here, we studied how AGEs contribute to development of early onset Parkinson's Disease (PD) caused by loss-of-function of DJ1, a protein deglycase. In induced pluripotent stem cell (iPSC)-derived midbrain organoid models deficient for DJ1 activity, we find that lysosomal proteolysis is impaired, causing AGEs to accumulate, α-synuclein (α-syn) phosphorylation to increase, and proteins to aggregate. We demonstrated these processes are at least partly driven by astrocytes, as DJ1 loss reduces their capacity to provide metabolic support and triggers acquisition of a pro-inflammatory phenotype. Consistently, in co-cultures, we find that DJ1-expressing astrocytes are able to reverse the proteolysis deficits of DJ1 knockout midbrain neurons. In conclusion, astrocytes' capacity to clear toxic damaged proteins is critical to preserve neuronal function and their dysfunction contributes to the neurodegeneration observed in a DJ1 loss-of-function PD model.
Assuntos
Doença de Parkinson , Humanos , Doença de Parkinson/genética , Proteostase , Astrócitos , Proteólise , Mesencéfalo , Organoides , LisossomosRESUMO
Lysine- and arginine-specific methyltransferases have been shown to act as either direct or secondary transcriptional co-activator of the estrogen receptor (ERα). However, little is known about the role of protein l-isoaspartyl O-methyltransferase (PIMT) on transcriptional regulation. Here, we show that PIMT acts as a co-activator for ERα-mediated transcription. Activation of the estrogen response element (ERE) promoter by ß-estradiol (E(2)) was suppressed by knockdown of PIMT, and enhanced by overexpression of wild-type PIMT. However, the ERE promoter activity was resistant to E(2) stimulation in cells overexpressing a catalytically inactive PIMT mutant, G88A. Consistent with these results, the expression of the endogenous ERα response gene trefoil factor 1 (TFF1) by E(2) was completely abrogated by PIMT depletion and decreased to approximately 50% when PIMT mutant G88A was expressed. In addition, over-expression of PIMT significantly increased the levels of TFF1 mRNA in the presence or absence of E(2). Interestingly, PIMT interacted with ERα and was distributed to the cytosol and the nucleus. The chromatin immunoprecipitation analysis revealed that PIMT was recruited to the promoter of TFF1 gene together with ERα in an E(2)-dependent manner, which was accompanied by uploading of RNA polymerase II on the promoter. Taken together, the results suggest that PIMT may act as a co-activator in ERα-mediated transcription through its recruitment to the promoter via interacting with ERα.
Assuntos
Receptor alfa de Estrogênio/metabolismo , Proteína D-Aspartato-L-Isoaspartato Metiltransferase/metabolismo , Transativadores/metabolismo , Ativação Transcricional , Proteínas Supressoras de Tumor/genética , Linhagem Celular Tumoral , Técnicas de Silenciamento de Genes , Humanos , Mutação , Regiões Promotoras Genéticas , Proteína D-Aspartato-L-Isoaspartato Metiltransferase/genética , Transativadores/genética , Fator Trefoil-1RESUMO
Adiponectin (encoded by Adipoq), a fat-derived hormone, alleviates risk factors associated with metabolic disorders. Although many transcription factors are known to control adiponectin expression, the mechanism underlying its fluctuation with regard to metabolic status remains unclear. Here, we show that ribosomal protein S6 kinase 1 (S6K1) controls adiponectin expression by inducing a transcriptional switch between two transcriptional machineries, BMAL1 and EZH2. Active S6K1 induced a suppressive histone code cascade, H2BS36p-EZH2-H3K27me3, leading to suppression of adiponectin expression. Moreover, active S6K1 phosphorylated BMAL1, an important transcription factor regulating the circadian clock system, at serine 42, which led to its dissociation from the Adipoq promoter region. This response resulted in EZH2 recruitment and subsequent H3K27me3 modification of the Adipoq promoter. Upon fasting, inactivation of S6K1 induced the opposite transcriptional switch, EZH2-to-BMAL1, promoting adiponectin expression. Consistently, S6K1-depleted mice exhibited lower H3K27me3 levels and elevated adiponectin expression. These findings identify a novel epigenetic switch system by which S6K1 controls the production of adiponectin, which displays beneficial effects on metabolism.
Assuntos
Fatores de Transcrição ARNTL , Adiponectina , Proteína Potenciadora do Homólogo 2 de Zeste , Proteínas Quinases S6 Ribossômicas , Fatores de Transcrição ARNTL/genética , Adiponectina/genética , Animais , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Regulação da Expressão Gênica , Código das Histonas , Camundongos , Proteínas Quinases S6 Ribossômicas/metabolismoRESUMO
Werner syndrome (WRN) is a rare progressive genetic disorder, caused by functional defects in WRN protein and RecQ4L DNA helicase. Acceleration of the aging process is initiated at puberty and the expected life span is approximately the late 50 s. However, a Wrn-deficient mouse model does not show premature aging phenotypes or a short life span, implying that aging processes differ greatly between humans and mice. Gene expression analysis of WRN cells reveals very similar results to gene expression analysis of Hutchinson Gilford progeria syndrome (HGPS) cells, suggesting that these human progeroid syndromes share a common pathological mechanism. Here we show that WRN cells also express progerin, an abnormal variant of the lamin A protein. In addition, we reveal that duplicated sequences of human WRN (hWRN) from exon 9 to exon 10, which differ from the sequence of mouse WRN (mWRN), are a natural inhibitor of progerin. Overexpression of hWRN reduced progerin expression and aging features in HGPS cells. Furthermore, the elimination of progerin by siRNA or a progerin-inhibitor (SLC-D011 also called progerinin) can ameliorate senescence phenotypes in WRN fibroblasts and cardiomyocytes, derived from WRN-iPSCs. These results suggest that progerin, which easily accumulates under WRN-deficient conditions, can lead to premature aging in WRN and that this effect can be prevented by SLC-D011.
Assuntos
Lamina Tipo A/metabolismo , Progéria/patologia , Helicase da Síndrome de Werner/metabolismo , Síndrome de Werner/genética , Adulto , Senilidade Prematura/genética , Animais , Linhagem Celular , Senescência Celular/efeitos dos fármacos , Criança , Modelos Animais de Doenças , Feminino , Fibroblastos/patologia , Expressão Gênica , Humanos , Masculino , Camundongos Mutantes , Progéria/genética , Isoformas de Proteínas , Síndrome de Werner/patologia , Helicase da Síndrome de Werner/genéticaRESUMO
Stem cells are characterized by self-renewal and by their ability to differentiate into cells of various organs. With massive progress in 2D and 3D cell culture techniques, in vitro generation of various types of such organoids from patient-derived stem cells is now possible. As in vitro differentiation protocols are usually made to resemble human developmental processes, organogenesis of patient-derived stem cells can provide key information regarding a range of developmental diseases. Human stem cell-based in vitro modeling as opposed to using animal models can particularly benefit the evaluation of neurological diseases because of significant differences in structure and developmental processes between the human and the animal brain. This review focuses on stem cell-based in vitro modeling of neurodevelopmental disorders, more specifically, the fundamentals and technical advancements in monolayer neuron and brain organoid cultures. Furthermore, we discuss the drawbacks of the conventional culture method and explore the advanced, cutting edge 3D organoid models for several neurodevelopmental diseases, including genetic diseases such as Down syndrome, Rett syndrome, and Miller-Dieker syndrome, as well as brain malformations like macrocephaly and microcephaly. Finally, we discuss the limitations of the current organoid techniques and some potential solutions that pave the way for accurate modeling of neurological disorders in a dish.