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1.
Nat Commun ; 11(1): 4677, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32938929

RESUMO

The Integrated Stress Response (ISR) helps metazoan cells adapt to cellular stress by limiting the availability of initiator methionyl-tRNA for translation. Such limiting conditions paradoxically stimulate the translation of ATF4 mRNA through a regulatory 5' leader sequence with multiple upstream Open Reading Frames (uORFs), thereby activating stress-responsive gene expression. Here, we report the identification of two critical regulators of such ATF4 induction, the noncanonical initiation factors eIF2D and DENR. Loss of eIF2D and DENR in Drosophila results in increased vulnerability to amino acid deprivation, susceptibility to retinal degeneration caused by endoplasmic reticulum (ER) stress, and developmental defects similar to ATF4 mutants. eIF2D requires its RNA-binding motif for regulation of 5' leader-mediated ATF4 translation. Consistently, eIF2D and DENR deficient human cells show impaired ATF4 protein induction in response to ER stress. Altogether, our findings indicate that eIF2D and DENR are critical mediators of ATF4 translational induction and stress responses in vivo.


Assuntos
Proteínas de Drosophila/genética , Drosophila melanogaster/genética , Estresse do Retículo Endoplasmático/genética , Fatores de Iniciação em Eucariotos/genética , Biossíntese de Proteínas , Fatores de Transcrição/genética , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Animais Geneticamente Modificados , Sítios de Ligação , Linhagem Celular , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/metabolismo , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Humanos , Mutação , Fases de Leitura Aberta , Interferência de RNA , Degeneração Retiniana/genética , Fatores de Transcrição/metabolismo
2.
J Toxicol Sci ; 45(9): 589-598, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32879258

RESUMO

Acute mercury chloride (HgCl2) poisoning may lead to kidney injury, but the underlying mechanism remains largely unknown. Endoplasmic reticulum (ER) stress plays a role in some heavy metal poisoning. Whether it mediates kidney injury in acute HgCl2 poisoning remains unknown. In this study, we examined the kidney injury and the corresponding ER stress in the mouse model of different doses of acute HgCl2 poisoning. To further confirm the role of ER stress, we tested the effects of its chemical chaperone [4-phenylbutyric acid (4-PBA)]. The results revealed that acute HgCl2 poisoning caused more severe kidney injury with dose on and activated ER stress, as indicated by increased expression of GRP78 and CHOP. Inhibition of ER stress restored the functional and morphological changes of kidneys, and partly attenuated renal tubular epithelial cell apoptosis. In summary, ER stress contributes to the acute kidney injury following HgCl2 poisoning, and inhibition of ER stress may alleviate the kidney injury via reducing apoptosis.


Assuntos
Lesão Renal Aguda/etiologia , Estresse do Retículo Endoplasmático/fisiologia , Cloreto de Mercúrio/envenenamento , Animais , Butilaminas , Modelos Animais de Doenças , Estresse do Retículo Endoplasmático/genética , Expressão Gênica , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Masculino , Camundongos Endogâmicos C57BL , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo
3.
Am J Chin Med ; 48(6): 1435-1454, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32907363

RESUMO

Endoplasmic reticulum stress (ER stress) plays a main role in pancreatic [Formula: see text]-cell dysfunction and death because of intracellular Ca[Formula: see text] turbulence and inflammation activation. Although several drugs are targeting pancreatic [Formula: see text]-cell to improve [Formula: see text]-cell function, there still lacks agents to alleviate [Formula: see text]-cell ER stress conditions. Therefore we used thapsigargin (THAP) or high glucose (HG) to induce ER stress in [Formula: see text]-cell and aimed to screen natural molecules against ER stress-induced [Formula: see text]-cell dysfunction. Through screening the Traditional Chinese drug library ([Formula: see text] molecules), luteolin was finally discovered to improve [Formula: see text]-cell function. Cellular viability results indicated luteolin reduced the THAP or HG-induced [Formula: see text]-cell death and apoptosis through MTT and flow cytometry assay. Moreover, luteolin improved [Formula: see text]-cell insulin secretion ability under ER stress conditions. Also ER stress-induced intracellular Ca[Formula: see text] turbulence and inflammation activation were inhibited by luteolin treatment. Mechanically, luteolin inhibited HNF4[Formula: see text] signaling, which was induced by ER stress. Moreover, luteolin reduced the transcriptional level of HNF4[Formula: see text] downstream gene, such as Asnk4b and HNF1[Formula: see text]. Conversely HNF4[Formula: see text] knockdown abolished the effect of luteolin on [Formula: see text]-cell using siRNA. These results suggested the protective effect of luteolin on [Formula: see text]-cell was through HNF4[Formula: see text]/Asnk4b pathway. In conclusion, our study discovered that luteolin improved [Formula: see text]-cell function and disclosed the underlying mechanism of luteolin on [Formula: see text]-cell, suggesting luteolin is a promising agent against pancreatic dysfunction.


Assuntos
Sobrevivência Celular/efeitos dos fármacos , Medicamentos de Ervas Chinesas/química , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Fator 4 Nuclear de Hepatócito/genética , Fator 4 Nuclear de Hepatócito/metabolismo , Células Secretoras de Insulina/patologia , Células Secretoras de Insulina/fisiologia , Luteolina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Tapsigargina/efeitos adversos , Apoptose/efeitos dos fármacos , Cálcio/metabolismo , Morte Celular/efeitos dos fármacos , Células Cultivadas , Avaliação Pré-Clínica de Medicamentos , Estresse do Retículo Endoplasmático/fisiologia , Glucose/efeitos adversos , Células Secretoras de Insulina/metabolismo , Luteolina/isolamento & purificação
4.
PLoS One ; 15(8): e0237669, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32810137

RESUMO

Pancreatic beta cell death is a hallmark of type 1 and 2 diabetes (T1D/T2D), but the underlying molecular mechanisms are incompletely understood. Key proteins of the DNA damage response (DDR), including tumor protein P53 (P53, also known as TP53 or TRP53 in rodents) and Ataxia Telangiectasia Mutated (ATM), a kinase known to act upstream of P53, have been associated with T2D. Here we test and compare the effect of ATM and P53 ablation on beta cell survival in the rat beta cell line Ins1E. We demonstrate that ATM and P53 differentially regulate beta cell apoptosis induced upon fundamentally different types of diabetogenic beta cell stress, including DNA damage, inflammation, lipotoxicity and endoplasmic reticulum (ER) stress. DNA damage induced apoptosis by treatment with the commonly used diabetogenic agent streptozotocin (STZ) is regulated by both ATM and P53. We show that ATM is a key STZ induced activator of P53 and that amelioration of STZ induced cell death by inhibition of ATM mainly depends on P53. While both P53 and ATM control lipotoxic beta cell apoptosis, ATM but not P53 fails to alter inflammatory beta cell death. In contrast, tunicamycin induced (ER stress associated) apoptosis is further increased by ATM knockdown or inhibition, but not by P53 knockdown. Our results reveal differential roles for P53 and ATM in beta cell survival in vitro in the context of four key pathophysiological types of diabetogenic beta cell stress, and indicate that ATM can use P53 independent signaling pathways to modify beta cell survival, dependent on the cellular insult.


Assuntos
Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Sobrevivência Celular/genética , Células Secretoras de Insulina/patologia , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Proteínas Mutadas de Ataxia Telangiectasia/antagonistas & inibidores , Proteínas Mutadas de Ataxia Telangiectasia/genética , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Diabetes Mellitus/patologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Técnicas de Silenciamento de Genes , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , RNA Interferente Pequeno/metabolismo , Ratos , Estreptozocina/toxicidade , Tunicamicina/toxicidade
5.
Life Sci ; 259: 118180, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32758622

RESUMO

AIMS: Bufothionine had been used for gastric cancer (GC) treatment, and this study managed to uncover the underlying mechanisms. MATERIALS AND METHODS: Cell proliferation was determined by CCK-8 assay and colony formation assay. Flow cytometry (FCM) and TUNEL assay were used to measure cell apoptosis ratio. Intracellular ROS was measured by DCFH-DA probes. qRT-PCR was used to determine miRNAs levels. Western Blot was performed to probe proteins. Dual-luciferase reporter gene system was employed to validate the binding sites of miR-133a-3p and 3'UTR regions of IGF1R mRNA. Immunohistochemistry (IHC) was used to determine the expressions of Ki-67 in mice tumor tissues. KEY FINDINGS: Bufothionine inhibited cell viability, triggered ER stress and promoted ROS production in GC cells, and both ER stress inhibitor Salburinal (Sal) and ROS scavenger (NAC) abrogated Bufothionine induced GC cell death. Besides, miR-133a-3p was upregulated by Bufothionine, and Bufothionine-induced cell death was enhanced by miR-133a-3p overexpression while alleviated by miR-133a-3p knockdown. Furthermore, miR-133a-3p inactivated PI3K/Akt signal pathway by sponging IGF1R, and Bufothionine inhibited insulin-like growth factor 1 receptor (IGF1R) and inactivated PI3K/Akt cascade by upregulating miR-133a-3p. Notably, the promoting effects of overexpressed miR-133a-3p on Bufothionine-induced GC cell death were abrogated by overexpressing IGF1R, and aggravated by the PI3K/Akt cascade inhibitor (LY294002). SIGNIFICANCE: Bufothionine promoted GC cell death by triggering miR-133a-3p/IGF1R/PI3K/Akt axis mediated ER stress and ROS production.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Alcaloides Indólicos/farmacologia , MicroRNAs/genética , Compostos de Quinolínio/farmacologia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Neoplasias Gástricas/patologia , Animais , Morte Celular/efeitos dos fármacos , Morte Celular/genética , Proliferação de Células , Cromonas/farmacologia , Humanos , Camundongos , Camundongos Endogâmicos BALB C , MicroRNAs/biossíntese , Morfolinas/farmacologia , Proteína Oncogênica v-akt/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Receptor IGF Tipo 1/efeitos dos fármacos , Ensaio Tumoral de Célula-Tronco , Regulação para Cima/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
6.
Mol Cell ; 79(6): 963-977.e3, 2020 09 17.
Artigo em Inglês | MEDLINE | ID: mdl-32735772

RESUMO

Autophagic degradation of the endoplasmic reticulum (ER-phagy) is triggered by ER stress in diverse organisms. However, molecular mechanisms governing ER stress-induced ER-phagy remain insufficiently understood. Here we report that ER stress-induced ER-phagy in the fission yeast Schizosaccharomyces pombe requires Epr1, a soluble Atg8-interacting ER-phagy receptor. Epr1 localizes to the ER through interacting with integral ER membrane proteins VAPs. Bridging an Atg8-VAP association is the main ER-phagy role of Epr1, as it can be bypassed by an artificial Atg8-VAP tether. VAPs contribute to ER-phagy not only by tethering Atg8 to the ER membrane, but also by maintaining the ER-plasma membrane contact. Epr1 is upregulated during ER stress by the unfolded protein response (UPR) regulator Ire1. Loss of Epr1 reduces survival against ER stress. Conversely, increasing Epr1 expression suppresses the ER-phagy defect and ER stress sensitivity of cells lacking Ire1. Our findings expand and deepen the molecular understanding of ER-phagy.


Assuntos
Estresse do Retículo Endoplasmático/genética , Endorribonucleases/genética , Proteínas R-SNARE/genética , Autofagossomos/metabolismo , Autofagia/genética , Família da Proteína 8 Relacionada à Autofagia/genética , Retículo Endoplasmático/genética , Regulação Fúngica da Expressão Gênica/genética , Proteólise , Schizosaccharomyces/genética , Proteínas de Schizosaccharomyces pombe/genética , Resposta a Proteínas não Dobradas/genética
7.
Nat Commun ; 11(1): 3306, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620754

RESUMO

The endoplasmic reticulum (ER) is selectively degraded by autophagy (ER-phagy) through proteins called ER-phagy receptors. In Saccharomyces cerevisiae, Atg40 acts as an ER-phagy receptor to sequester ER fragments into autophagosomes by binding Atg8 on forming autophagosomal membranes. During ER-phagy, parts of the ER are morphologically rearranged, fragmented, and loaded into autophagosomes, but the mechanism remains poorly understood. Here we find that Atg40 molecules assemble in the ER membrane concurrently with autophagosome formation via multivalent interaction with Atg8. Atg8-mediated super-assembly of Atg40 generates highly-curved ER regions, depending on its reticulon-like domain, and supports packing of these regions into autophagosomes. Moreover, tight binding of Atg40 to Atg8 is achieved by a short helix C-terminal to the Atg8-family interacting motif, and this feature is also observed for mammalian ER-phagy receptors. Thus, this study significantly advances our understanding of the mechanisms of ER-phagy and also provides insights into organelle fragmentation in selective autophagy of other organelles.


Assuntos
Autofagossomos/metabolismo , Proteínas Relacionadas à Autofagia/metabolismo , Autofagia , Retículo Endoplasmático/metabolismo , Membranas Intracelulares/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Sequência de Aminoácidos , Família da Proteína 8 Relacionada à Autofagia/química , Família da Proteína 8 Relacionada à Autofagia/genética , Família da Proteína 8 Relacionada à Autofagia/metabolismo , Proteínas Relacionadas à Autofagia/química , Proteínas Relacionadas à Autofagia/genética , Sítios de Ligação/genética , Estresse do Retículo Endoplasmático/genética , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Proteínas de Membrana/química , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Microscopia de Fluorescência , Mutação , Ligação Proteica , Domínios Proteicos , Receptores Citoplasmáticos e Nucleares/química , Receptores Citoplasmáticos e Nucleares/genética , Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/genética
8.
PLoS One ; 15(7): e0236424, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32730292

RESUMO

Grapevines, although adapted to occasional drought or salt stress, are relatively sensitive to growth- and yield-limiting salinity stress. To understand the molecular mechanisms of salt tolerance and endoplasmic reticulum (ER) stress and identify genes commonly regulated by both stresses in grapevine, we investigated transcript profiles in leaves of the salt-tolerant grapevine rootstock 1616C under salt- and ER-stress. Among 1643 differentially expressed transcripts at 6 h post-treatment in leaves, 29 were unique to ER stress, 378 were unique to salt stress, and 16 were common to both stresses. At 24 h post-treatment, 243 transcripts were unique to ER stress, 1150 were unique to salt stress, and 168 were common to both stresses. GO term analysis identified genes in categories including 'oxidative stress', 'protein folding', 'transmembrane transport', 'protein phosphorylation', 'lipid transport', 'proteolysis', 'photosynthesis', and 'regulation of transcription'. The expression of genes encoding transporters, transcription factors, and proteins involved in hormone biosynthesis increased in response to both ER and salt stresses. KEGG pathway analysis of differentially expressed genes for both ER and salt stress were divided into four main categories including; carbohydrate metabolism, amino acid metabolism, signal transduction and lipid metabolism. Differential expression of several genes was confirmed by qRT-PCR analysis, which validated our microarray results. We identified transcripts for genes that might be involved in salt tolerance and also many genes differentially expressed under both ER and salt stresses. Our results could provide new insights into the mechanisms of salt tolerance and ER stress in plants and should be useful for genetic improvement of salt tolerance in grapevine.


Assuntos
Estresse do Retículo Endoplasmático/genética , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Raízes de Plantas/genética , Estresse Salino/genética , Vitis/genética , Metabolismo dos Carboidratos/genética , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Ontologia Genética , Análise de Sequência com Séries de Oligonucleotídeos , Osmose , Reguladores de Crescimento de Planta/farmacologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/efeitos dos fármacos , Caules de Planta/efeitos dos fármacos , Caules de Planta/fisiologia , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Estresse Salino/efeitos dos fármacos , Cloreto de Sódio/farmacologia , Fatores de Transcrição/metabolismo , Tunicamicina/farmacologia
9.
Toxicol Lett ; 331: 178-187, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32569804

RESUMO

Chromium (Cr) (VI) compounds are known to be serious toxic and carcinogenic, but the mechanism is not clear. In our previous study, we found that Cr (VI)-induced ER stress plays an important role in the crosstalk between apoptosis and autophagy, while autophagy was apoptosis-dependent and subsequently prevents apoptosis cell death to keep A549 cells resistant to Cr (VI)-induced toxicity. In this study, we found that Cr (VI) could induce aerobic glycolysis in A549 cells. Both ER stress inhibitor, phenylbutyric acid (4-PBA) and the inhibitor of autophagy, 3-MA, repressed Cr (VI)-induced glycolysis, indicating that both ER stress and autophagy were involved in Cr (VI)-induced glycolysis in A549 cells. Co-treatment of the inhibitor of aerobic glycolysis, 2-DG and Cr (VI) for 24 h increased Cr (VI)-induced cleaved caspase-3, caspase-9 and the number of apoptotic cells, demonstrating that aerobic glycolysis played an important role in attenuating Cr (VI)-induced apoptosis. Furthermore, knockdown of ATF4 by siATF4 significantly decreased Cr (VI)-induced aerobic glycolysis and apoptosis, suggesting that ATF4 was involved in Cr (VI)-induced aerobic glycolysis and its effect of attenuating apoptosis in A549 cells. Taken together, our results demonstrated that autophagy-dependent glycolysis played a role in attenuating Cr (VI)-induced apoptosis. ER stress was involved in facilitating glycolysis, whose induction was mediated by ATF4. These findings open a window for the development of therapeutic interventions to prevent Cr (VI)-induced toxicity.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Cromo/toxicidade , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Glicólise/efeitos dos fármacos , Células A549 , Fator 4 Ativador da Transcrição/genética , Apoptose/genética , Autofagia/genética , Estresse do Retículo Endoplasmático/genética , Técnicas de Silenciamento de Genes , Glicólise/genética , Humanos
10.
Gene ; 755: 144884, 2020 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-32562739

RESUMO

The aim of this work was to study changes in gene expression levels of 7 ER-resident selenoproteins under ER-stress caused by the action of a selenium-containing compound of organic nature, methylselenic acid using three human cancer cell lines DU 145 (prostate carcinoma), MCF 7 (breast adenocarcinoma)and HT-1080 (fibrosarcoma). According to the obtained results, we can speak of a synchronous changes in the expression of SELT and SEP15 mRNA depending on the concentration of MSA for 24 h, while the pattern of SELM expression was completely opposite and was radically different from other selenoproteins. It should be noted that in HT-1080 cells, the expression pattern of SELM differed from the expression pattern in two other cancer cells, while the expression patterns of other ER-resident selenoproteins (SELT, SEP15, SELK, SELS, SELN and DIO2) differed slightly depending on the cell line. Also we investigated the molecular mechanisms of UPR caused by MSA-induced ER stress in three cancer cell lines. According to the obtained results, it can be assumed that in DU 145 cells, MSA promotes activation of the PERK signaling pathway of UPR. In fibrosarcoma cells MSA was promoted the activation of ATF-6 UPR signaling pathway. In MCF 7 cells, MSA promoted the activation of two pro-apoptotic UPR signaling pathways at once: IRE1 and ATF-6.The results of this work once again demonstrate that the mechanisms of ER-stress regulation caused by the same agent, in this case, MSA, lead to the activation of different UPR signaling pathways in different cancer cells, and about their relationship.


Assuntos
Estresse do Retículo Endoplasmático/genética , Compostos Organosselênicos/metabolismo , Selenoproteínas/genética , Apoptose/genética , Linhagem Celular Tumoral , Retículo Endoplasmático/metabolismo , Expressão Gênica/genética , Regulação da Expressão Gênica/genética , Humanos , RNA Mensageiro/genética , Selenoproteínas/metabolismo , Transdução de Sinais/genética , Resposta a Proteínas não Dobradas/genética
11.
Am J Chin Med ; 48(4): 967-985, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32431178

RESUMO

Inflammation and endoplasmic reticulum (ER) stress have been documented to contribute to the development of atherosclerosis. Ginsenoside Rb2 has been reported to exhibit antidiabetic effects. However, the effects of Rb2 on atherosclerotic responses such as inflammation and ER stress in endothelial cells and monocytes remain unclear. In this study, the expression of inflammation and ER stress markers was determined using a Western blotting method. Concentrations of tumor necrosis factor alpha (TNF[Formula: see text]) and monocyte chemoattractant protein-1 (MCP-1) in culture media were assessed by enzyme-linked immunosorbent assay (ELISA) and apoptosis was evaluated by a cell viability assay and a caspase-3 activity measurement kit. We found that exposure of HUVECs and THP-1 monocytes to Rb2 attenuated inflammation and ER stress, resulting in amelioration of apoptosis and THP-1 cell adhesion to HUVECs under lipopolysaccharide (LPS) condition. Increased AMPK phosphorylation and heme oxygenase (HO)-1 expression, including GPR120 expression were observed in Rb2-treated HUVECs and THP-1 monocytes. Downregulation of both, AMPK phosphorylation and HO-1expression rescued these observed changes. Furthermore, GPR120 siRNA mitigated Rb2-induced AMPK phosphorylation. These results suggest that Rb2 inhibits LPS-mediated apoptosis and THP-1 cell adhesion to HUVECs by GPR120/AMPK/HO-1-associated attenuating inflammation and ER stress. Therefore, Rb2 can be used as a potential therapeutic molecule for treatment of atherosclerosis.


Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Aterosclerose/tratamento farmacológico , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Ginsenosídeos/farmacologia , Ginsenosídeos/uso terapêutico , Lipopolissacarídeos/efeitos adversos , Fitoterapia , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Apoptose/efeitos dos fármacos , Apoptose/genética , Aterosclerose/induzido quimicamente , Aterosclerose/genética , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Expressão Gênica/efeitos dos fármacos , Heme Oxigenase-1/genética , Heme Oxigenase-1/metabolismo , Células Endoteliais da Veia Umbilical Humana , Humanos , Inflamação , Fosforilação/efeitos dos fármacos , Receptores Acoplados a Proteínas-G/genética , Receptores Acoplados a Proteínas-G/metabolismo , Células THP-1 , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo
12.
Nucleic Acids Res ; 48(W1): W218-W229, 2020 07 02.
Artigo em Inglês | MEDLINE | ID: mdl-32427338

RESUMO

Ribosome profiling (Ribo-seq) is a powerful technology for globally monitoring RNA translation; ranging from codon occupancy profiling, identification of actively translated open reading frames (ORFs), to the quantification of translational efficiency under various physiological or experimental conditions. However, analyzing and decoding translation information from Ribo-seq data is not trivial. Although there are many existing tools to analyze Ribo-seq data, most of these tools are designed for specific or limited functionalities and an easy-to-use integrated tool to analyze Ribo-seq data is lacking. Fortunately, the small size (26-34 nt) of ribosome protected fragments (RPFs) in Ribo-seq and the relatively small amount of sequencing data greatly facilitates the development of such a web platform, which is easy to manipulate for users with or without bioinformatic expertise. Thus, we developed RiboToolkit (http://rnabioinfor.tch.harvard.edu/RiboToolkit), a convenient, freely available, web-based service to centralize Ribo-seq data analyses, including data cleaning and quality evaluation, expression analysis based on RPFs, codon occupancy, translation efficiency analysis, differential translation analysis, functional annotation, translation metagene analysis, and identification of actively translated ORFs. Besides, easy-to-use web interfaces were developed to facilitate data analysis and intuitively visualize results. Thus, RiboToolkit will greatly facilitate the study of mRNA translation based on ribosome profiling.


Assuntos
Códon , Biossíntese de Proteínas , Ribossomos , Software , Células 3T3 , Animais , Estresse do Retículo Endoplasmático/genética , Camundongos , Anotação de Sequência Molecular , Fases de Leitura Aberta , RNA Mensageiro/metabolismo , Análise de Sequência de RNA
13.
Am J Physiol Endocrinol Metab ; 319(1): E146-E162, 2020 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-32421370

RESUMO

Secreted hormones facilitate tissue cross talk to maintain energy balance. We previously described C1q/TNF-related protein 12 (CTRP12) as a novel metabolic hormone. Gain-of-function and partial-deficiency mouse models have highlighted important roles for this fat-derived adipokine in modulating systemic metabolism. Whether CTRP12 is essential and required for metabolic homeostasis is unknown. We show here that homozygous deletion of Ctrp12 gene results in sexually dimorphic phenotypes. Under basal conditions, complete loss of CTRP12 had little impact on male mice, whereas it decreased body weight (driven by reduced lean mass and liver weight) and improved insulin sensitivity in female mice. When challenged with a high-fat diet, Ctrp12 knockout (KO) male mice had decreased energy expenditure, increased weight gain and adiposity, elevated serum TNFα level, and reduced insulin sensitivity. In contrast, female KO mice had reduced weight gain and liver weight. The expression of lipid synthesis and catabolism genes, as well as profibrotic, endoplasmic reticulum stress, and oxidative stress genes were largely unaffected in the adipose tissue of Ctrp12 KO male mice. Despite greater adiposity and insulin resistance, Ctrp12 KO male mice fed an obesogenic diet had lower circulating triglyceride and free fatty acid levels. In contrast, lipid profiles of the leaner female KO mice were not different from those of WT controls. These data suggest that CTRP12 contributes to whole body energy metabolism in genotype-, diet-, and sex-dependent manners, underscoring complex gene-environment interactions influencing metabolic outcomes.


Assuntos
Adipocinas/genética , Peso Corporal/genética , Dieta Hiperlipídica , Metabolismo Energético/genética , Resistência à Insulina/genética , Tecido Adiposo/metabolismo , Adiposidade/genética , Animais , Estresse do Retículo Endoplasmático/genética , Ácidos Graxos não Esterificados/metabolismo , Feminino , Fibrose/genética , Expressão Gênica , Interação Gene-Ambiente , Metabolismo dos Lipídeos/genética , Fígado/patologia , Masculino , Camundongos , Camundongos Knockout , Tamanho do Órgão , Estresse Oxidativo/genética , Fatores Sexuais , Triglicerídeos/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Ganho de Peso/genética
14.
PLoS One ; 15(5): e0231894, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32365111

RESUMO

Stress granules (SG) are cytoplasmic RNA granules that form during various types of stress known to inhibit general translation, including oxidative stress, hypoxia, endoplasmic reticulum stress (ER), ionizing radiations or viral infection. Induction of these SG promotes cell survival in part through sequestration of proapoptotic molecules, resulting in the inactivation of cell death pathways. SG also form in cancer cells, but studies investigating their formation upon treatment with chemotherapeutics are very limited. Here we identified Lapatinib (Tykerb / Tyverb®), a tyrosine kinase inhibitor used for the treatment of breast cancers as a new inducer of SG in breast cancer cells. Lapatinib-induced SG formation correlates with the inhibition of general translation initiation which involves the phosphorylation of the translation initiation factor eIF2α through the kinase PERK. Disrupting PERK-SG formation by PERK depletion experiments sensitizes resistant breast cancer cells to Lapatinib. This study further supports the assumption that treatment with anticancer drugs activates the SG pathway, which may constitute an intrinsic stress response used by cancer cells to resist treatment.


Assuntos
Grânulos Citoplasmáticos/efeitos dos fármacos , Lapatinib/uso terapêutico , Neoplasias/tratamento farmacológico , Biossíntese de Proteínas/efeitos dos fármacos , Linhagem Celular Tumoral , Grânulos Citoplasmáticos/metabolismo , Grânulos Citoplasmáticos/patologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Estresse do Retículo Endoplasmático/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Humanos , Lapatinib/farmacologia , Células MCF-7 , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Fosforilação/efeitos dos fármacos , Regulação para Cima/efeitos dos fármacos , Regulação para Cima/genética , eIF-2 Quinase/metabolismo
15.
Am J Physiol Endocrinol Metab ; 318(6): E892-E900, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32255680

RESUMO

Proinsulin is a misfolding-prone protein, and its efficient breakdown is critical when ß-cells are confronted with high-insulin biosynthetic demands, to prevent endoplasmic reticulum stress, a key trigger of secretory dysfunction and, if uncompensated, apoptosis. Proinsulin degradation is thought to be performed by the constitutively expressed standard proteasome, while the roles of other proteasomes are unknown. We recently demonstrated that deficiency of the proinsulin chaperone glucose-regulated protein 94 (GRP94) causes impaired proinsulin handling and defective insulin secretion associated with a compensated endoplasmic reticulum stress response. Taking advantage of this model of restricted folding capacity, we investigated the role of different proteasomes in proinsulin degradation, reasoning that insulin secretory dynamics require an inducible protein degradation system. We show that the expression of only one enzymatically active proteasome subunit, namely, the inducible ß5i-subunit, was increased in GRP94 CRISPR/Cas9 knockout (KO) cells. Additionally, the level of ß5i-containing intermediate proteasomes was significantly increased in these cells, as was ß5i-related chymotrypsin-like activity. Moreover, proinsulin levels were restored in GRP94 KO upon ß5i small interfering RNA-mediated knockdown. Finally, the fraction of ß-cells expressing the ß5i-subunit is increased in human islets from type 2 diabetes patients. We conclude that ß5i is an inducible proteasome subunit dedicated to the degradation of mishandled proinsulin.


Assuntos
Diabetes Mellitus Tipo 2/genética , Estresse do Retículo Endoplasmático/genética , Degradação Associada com o Retículo Endoplasmático/genética , Secreção de Insulina/genética , Células Secretoras de Insulina/metabolismo , Proinsulina/metabolismo , Complexo de Endopeptidases do Proteassoma/genética , Animais , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Técnicas de Inativação de Genes , Humanos , Ilhotas Pancreáticas/metabolismo , Glicoproteínas de Membrana/genética , Pessoa de Meia-Idade , Complexo de Endopeptidases do Proteassoma/metabolismo , Dobramento de Proteína , Ratos
16.
PLoS Biol ; 18(3): e3000296, 2020 03.
Artigo em Inglês | MEDLINE | ID: mdl-32163401

RESUMO

The steady increase in the prevalence of obesity and associated type II diabetes mellitus is a major health concern, particularly among children. Maternal obesity represents a risk factor that contributes to metabolic perturbations in the offspring. Endoplasmic reticulum (ER) stress has emerged as a critical mechanism involved in leptin resistance and type 2 diabetes in adult individuals. Here, we used a mouse model of maternal obesity to investigate the importance of early life ER stress in the nutritional programming of this metabolic disease. Offspring of obese dams developed glucose intolerance and displayed increased body weight, adiposity, and food intake. Moreover, maternal obesity disrupted the development of melanocortin circuits associated with neonatal hyperleptinemia and leptin resistance. ER stress-related genes were up-regulated in the hypothalamus of neonates born to obese mothers. Neonatal treatment with the ER stress-relieving drug tauroursodeoxycholic acid improved metabolic and neurodevelopmental deficits and reversed leptin resistance in the offspring of obese dams.


Assuntos
Estresse do Retículo Endoplasmático , Hipotálamo/crescimento & desenvolvimento , Obesidade Materna/metabolismo , Animais , Animais Recém-Nascidos , Axônios/efeitos dos fármacos , Axônios/metabolismo , Composição Corporal , Peso Corporal , Dieta/efeitos adversos , Estresse do Retículo Endoplasmático/genética , Feminino , Hipotálamo/efeitos dos fármacos , Hipotálamo/embriologia , Hipotálamo/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Pâncreas/crescimento & desenvolvimento , Gravidez , Efeitos Tardios da Exposição Pré-Natal , Pró-Opiomelanocortina/metabolismo , Ácido Tauroquenodesoxicólico/farmacologia , alfa-MSH/metabolismo
17.
Proc Natl Acad Sci U S A ; 117(11): 5987-5996, 2020 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-32123111

RESUMO

Endogenous retroviruses and long terminal repeat (LTR) retrotransposons are mobile genetic elements that are closely related to retroviruses. Desilenced endogenous retroviruses are associated with human autoimmune disorders and neurodegenerative diseases. Caenorhabditis elegans and related Caenorhabditis spp. contain LTR retrotransposons and, as described here, numerous integrated viral genes including viral envelope genes that are part of LTR retrotransposons. We found that both LTR retrotransposons and endogenous viral elements are silenced by ADARs [adenosine deaminases acting on double-stranded RNA (dsRNA)] together with the endogenous RNA interference (RNAi) factor ERI-6/7, a homolog of MOV10 helicase, a retrotransposon and retrovirus restriction factor in human. siRNAs corresponding to integrated viral genes and LTR retrotransposons, but not to DNA transposons, are dependent on the ADARs and ERI-6/7. siRNAs corresponding to palindromic repeats are independent of the ADARs and ERI-6/7, and are in fact increased in adar- and eri-6/7-defective mutants because of an antiviral RNAi response to dsRNA. Silencing of LTR retrotransposons is dependent on downstream RNAi factors and P granule components but is independent of the viral sensor DRH-1/RIG-I and the nuclear Argonaute NRDE-3. The activation of retrotransposons in the ADAR- and ERI-6/7/MOV10-defective mutant is associated with the induction of the unfolded protein response (UPR), a common response to viral infection. The overlap between genes induced upon viral infection and infection with intracellular pathogens and genes coexpressed with retrotransposons suggests that there is a common response to different types of foreign elements that includes a response to proteotoxicity presumably caused by the burden of replicating pathogens and expressed retrotransposons.


Assuntos
Caenorhabditis elegans/genética , Retrovirus Endógenos/genética , Interações entre Hospedeiro e Microrganismos/genética , Interferência de RNA , Retroelementos/genética , Adenosina Desaminase/genética , Adenosina Desaminase/metabolismo , Animais , Caenorhabditis elegans/virologia , Proteínas de Caenorhabditis elegans/metabolismo , DNA Helicases/metabolismo , DNA Viral/metabolismo , Estresse do Retículo Endoplasmático/genética , Regulação Viral da Expressão Gênica , Genes Virais/genética , Humanos , RNA de Cadeia Dupla/metabolismo , RNA Viral/metabolismo , Homologia de Sequência de Aminoácidos , Sequências Repetidas Terminais/genética , Resposta a Proteínas não Dobradas/genética
18.
Artigo em Inglês | MEDLINE | ID: mdl-32186893

RESUMO

Selenoprotein S (Seps1) can be protective against oxidative, endoplasmic reticulum (ER), and inflammatory stress. Seps1 global knockout mice are less active, possess compromised fast muscle ex vivo strength, and, depending on context, heightened inflammation. Oxidative, ER, and inflammatory stress modulates contractile function; hence, our aim was to investigate the effects of Seps1 gene dose on exercise performance. Seps1-/- knockout, Seps1-/+ heterozygous, and wild-type mice were randomized to 3 days of incremental, high-intensity treadmill running or a sedentary control group. On day 4, the in situ contractile function of fast tibialis anterior (TA) muscles was determined. Seps1 reduction or deletion compromised exercise capacity, decreasing distance run. TA strength was also reduced. In sedentary Seps1-/- knockout mice, TA fatigability was greater than wild-type mice, and this was ameliorated with exercise. Whereas, in Seps1+/- heterozygous mice, exercise compromised TA endurance. These impairments in exercise capacity and TA contractile function were not associated with increased inflammation or a dysregulated redox state. Seps1 is highly expressed in muscle fibers and blood vessels. Interestingly, Nos1 and Vegfa mRNA transcripts were decreased in TA muscles from Seps1-/- knockout and Seps1-/+ heterozygous mice. Impaired exercise performance with Seps1 reduction or deletion cannot be attributed to heightened cellular stress, but it may potentially be mediated, in part, by the effects of Seps1 on the microvasculature.


Assuntos
Citocinas/sangue , Estresse do Retículo Endoplasmático , Tolerância ao Exercício , Mediadores da Inflamação/sangue , Contração Isométrica , Proteínas de Membrana/deficiência , Músculo Esquelético/irrigação sanguínea , Músculo Esquelético/metabolismo , Estresse Oxidativo , Condicionamento Físico Animal , Selenoproteínas/deficiência , Animais , Citocinas/genética , Estresse do Retículo Endoplasmático/genética , Regulação da Expressão Gênica , Masculino , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Camundongos Knockout , Microcirculação , Fadiga Muscular , Fibras Musculares de Contração Rápida/metabolismo , Fibras Musculares de Contração Rápida/patologia , Força Muscular , Músculo Esquelético/patologia , Oxirredução , Estresse Oxidativo/genética , Corrida , Selenoproteínas/genética , Fatores de Tempo
19.
Stroke ; 51(5): 1570-1577, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32212900

RESUMO

Background and Purpose- Ischemic stroke impairs endoplasmic reticulum (ER) function, causes ER stress, and activates the unfolded protein response. The unfolded protein response consists of 3 branches controlled by ER stress sensor proteins, which include PERK (protein kinase RNA-like ER kinase). Activated PERK phosphorylates eIF2α (eukaryotic initiation factor 2 alpha), resulting in inhibition of global protein synthesis. Here, we aimed to clarify the role of the PERK unfolded protein response branch in stroke. Methods- Neuron-specific and tamoxifen-inducible PERK conditional knockout (cKO) mice were generated by cross-breeding Camk2a-CreERT2 with Perkf/f mice. Transient middle cerebral artery occlusion was used to induce stroke. Short- and long-term stroke outcomes were evaluated. Protein synthesis in the brain was assessed using a surface-sensing-of-translation approach. Results- After tamoxifen-induced deletion of Perk in forebrain neurons was confirmed in PERK-cKO mice, PERK-cKO and control mice were subjected to transient middle cerebral artery occlusion and 3 days or 3 weeks recovery. PERK-cKO mice had larger infarcts and worse neurological outcomes compared with control mice, suggesting that PERK-induced eIF2α phosphorylation and subsequent suppression of translation protects neurons from ischemic stress. Indeed, better stroke outcomes were observed in PERK-cKO mice that received postischemic treatment with salubrinal, which can restore the ischemia-induced increase in phosphorylated eIF2α in these mice. Finally, our data showed that post-treatment with salubrinal improved functional recovery after stroke. Conclusions- Here, we presented the first evidence that postischemic suppression of translation induced by PERK activation promotes recovery of neurological function after stroke. This confirms and further extends our previous observations that recovery of ER function impaired by ischemic stress critically contributes to stroke outcome. Therefore, future research should include strategies to improve stroke outcome by targeting unfolded protein response branches to restore protein homeostasis in neurons.


Assuntos
Estresse do Retículo Endoplasmático/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Infarto da Artéria Cerebral Média/metabolismo , Neurônios/metabolismo , Neuroproteção/genética , Resposta a Proteínas não Dobradas/genética , eIF-2 Quinase/genética , Animais , Isquemia Encefálica/metabolismo , Isquemia Encefálica/fisiopatologia , Cinamatos/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/efeitos dos fármacos , Infarto da Artéria Cerebral Média/fisiopatologia , Camundongos , Camundongos Knockout , Fosforilação , Biossíntese de Proteínas/efeitos dos fármacos , Biossíntese de Proteínas/genética , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/fisiopatologia , Tioureia/análogos & derivados , Tioureia/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos
20.
Biochim Biophys Acta Mol Basis Dis ; 1866(6): 165752, 2020 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-32119897

RESUMO

Mood disorders like major depression and bipolar disorder (BD) are among the most prevalent forms of mental illness. Current knowledge of the neurobiology and pathophysiology of these disorders is still modest and clear biological markers are still missing. Thus, a better understanding of the underlying pathophysiological mechanisms to identify potential therapeutic targets is a prerequisite for the design of new drugs as well as to develop biomarkers that help in a more accurate and earlier diagnosis. Multiple pieces of evidence including genetic and neuro-imaging studies suggest that mood disorders are associated with abnormalities in endoplasmic-reticulum (ER)-related stress responses, mitochondrial function and calcium signalling. Furthermore, deregulation of the innate immune response has been described in patients diagnosed with mood disorders, including depression and BD. These disease-related events are associated with functions localized to a subdomain of the ER, known as Mitochondria-Associated Membranes (MAMs), which are lipid rafts-like domains that connect mitochondria and ER, both physically and biochemically. This review will outline the current understanding of the role of mitochondria and ER dysfunction under pathological brain conditions, particularly in major depressive disorder (MDD) and BD, that support the hypothesis that MAMs can act in these mood disorders as the link connecting ER-related stress response and mitochondrial impairment, as well as a mechanisms behind sterile inflammation arising from deregulation of innate immune responses. The role of MAMs in the pathophysiology of these pathologies and its potential relevance as a potential therapeutic target will be discussed.


Assuntos
Retículo Endoplasmático/metabolismo , Mitocôndrias/metabolismo , Membranas Mitocondriais/metabolismo , Transtornos do Humor/imunologia , Sinalização do Cálcio/genética , Retículo Endoplasmático/patologia , Estresse do Retículo Endoplasmático/genética , Humanos , Imunidade Inata/genética , Microdomínios da Membrana/genética , Microdomínios da Membrana/patologia , Mitocôndrias/patologia , Membranas Mitocondriais/patologia , Transtornos do Humor/genética , Transtornos do Humor/metabolismo , Transtornos do Humor/patologia
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