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1.
Life Sci ; 237: 116944, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31604108

RESUMO

AIMS: Endoplasmic reticulum stress (ERS) is an evolutionarily conserved cell stress response. Recently, it was found that ERS induces not only apoptosis but also endoplasmic reticulophagy (ER-phagy). A previous study demonstrated that inhibition of ER-phagy alleviates cell injury. The purpose of this study was to investigate the involvement of the protein kinase R-like ER kinase (PERK)/nuclear factor erythroid 2-related factor 2 (Nrf2) pathway in ERS-induced ER-phagy in H9c2 cardiomyoblasts. To address this aim, cells were treated with ERS inhibitors and a Nrf2 inhibitor before establishment of thapsigargin (TG)- or tunicamycin (TM)-induced ERS models in H9c2 cardiomyoblasts. MAIN METHODS: Transmission electron microscopy and immunofluorescence staining were used to detect ER-phagy. Western blotting was employed to detect the levels of calreticulin (CRT), total and phosphorylated PERK, nuclear Nrf2, activated transcription factor 4 (ATF4), light chain 3B (LC3B)-II and Beclin 1. Immunofluorescence staining was used to assess subcellular location of Nrf2. KEY FINDING: TG or TM induced H9c2 cell injury and ER-phagy and upregulated CRT expression, PERK phosphorylation, Nrf2 nuclear translocation, and expression of ATF4, Beclin 1, and LC3B-II compared with control cells. Treatment with ERS inhibitors decreased TG- or TM-induced ER-phagy, downregulated CRT expression, PERK phosphorylation, Nrf2 nuclear translocation and the expression of ATF4, Beclin 1 and LC3B-II. Moreover, a Nrf2 inhibitor downregulated the expression of ATF4, Beclin 1 and LC3B-II and alleviated TG- or TM-induced ER-phagy and H9c2 cell injury. SIGNIFICANCE: These findings suggest that the PERK/Nrf2 pathway mediates upregulation of ER-phagy, thereby inducing cell injury in H9c2 cardiomyoblasts.


Assuntos
Apoptose , Estresse do Retículo Endoplasmático , Retículo Endoplasmático/patologia , Miócitos Cardíacos/patologia , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo , eIF-2 Quinase/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Animais , Proteína Beclina-1/metabolismo , Células Cultivadas , Retículo Endoplasmático/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Miócitos Cardíacos/metabolismo , Fosforilação , Ratos , Transdução de Sinais
2.
Life Sci ; 232: 116612, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31260687

RESUMO

AIMS: Accumulating evidence suggest that endoplasmic reticulum (ER) stress is an important mechanism underlying the development of diabetes. We have reported that sustained treatment with N-methyl-d-aspartate (NMDA) results in apoptotic ß-cell death and impairs insulin secretion. However, the molecular mechanism responsible for NMDA-induced ß-cell dysfunction remains largely obscure. Thus, this study aimed to determine whether sustained activation of NMDA receptors (NMDARs) causes ß-cell dysfunction through ER stress. MAIN METHODS: Primary mouse islets and MIN6 mouse pancreatic ß-cells were treated with NMDA for 24 h or high-glucose for 72 h. After the treatment, glucose-stimulated insulin secretion (GSIS) and the expression of ER stress markers were measured, respectively. In vivo, the expression of ER stress markers was measured in the pancreas of diabetic mice treated with or without NMDARs inhibitor Memantine. KEY FINDINGS: NMDA treatment caused an increase in the expression of ER stress markers (ATF4, CHOP, GRP78, and Xbp1s) in primary islets. While, tauroursodeoxycholic acid (TUDCA), an inhibitor of ER stress, significantly attenuated NMDA-induced ß-cell dysfunction, including the loss of glucose-stimulated insulin secretion and reduction of pancreas duodenum homeobox factor-1 (Pdx-1) mRNA expression, a transcription factor regulating insulin synthesis. Besides, NMDA-induced ER stress strongly promoted pro-inflammatory cytokines synthesis (IL-1ß and TNF-α) in ß cells. Interestingly, knockdown of CHOP attenuated ß-cell dysfunction evoked by NMDA. Furthermore, we demonstrated that blockade of NMDARs ameliorated high-glucose-induced ER stress in vitro and in vivo. SIGNIFICANCE: This study confirms that ER stress is actively involved in the activation of NMDARs-related ß-cell dysfunction.


Assuntos
Estresse do Retículo Endoplasmático/fisiologia , Células Secretoras de Insulina/metabolismo , Fator de Transcrição CHOP/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Diabetes Mellitus Experimental/metabolismo , Modelos Animais de Doenças , Retículo Endoplasmático/metabolismo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Glucose/metabolismo , Proteínas de Choque Térmico/metabolismo , Insulina/metabolismo , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , N-Metilaspartato/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Transdução de Sinais , Proteína 1 de Ligação a X-Box/metabolismo
3.
PLoS Pathog ; 15(6): e1007746, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31194856

RESUMO

Toxoplasma gondii is a prevalent protozoan parasite that can infect any nucleated cell but cannot replicate outside of its host cell. Toxoplasma is auxotrophic for several nutrients including arginine, tryptophan, and purines, which it must acquire from its host cell. The demands of parasite replication rapidly deplete the host cell of these essential nutrients, yet Toxoplasma successfully manages to proliferate until it lyses the host cell. In eukaryotic cells, nutrient starvation can induce the integrated stress response (ISR) through phosphorylation of an essential translation factor eIF2. Phosphorylation of eIF2 lowers global protein synthesis coincident with preferential translation of gene transcripts involved in stress adaptation, such as that encoding the transcription factor ATF4 (CREB2), which activates genes that modulate amino acid metabolism and uptake. Here, we discovered that the ISR is induced in host cells infected with Toxoplasma. Our results show that as Toxoplasma depletes host cell arginine, the host cell phosphorylates eIF2 via protein kinase GCN2 (EIF2AK4), leading to induced ATF4. Increased ATF4 then enhances expression of the cationic amino acid transporter CAT1 (SLC7A1), resulting in increased uptake of arginine in Toxoplasma-infected cells. Deletion of host GCN2, or its downstream effectors ATF4 and CAT1, lowers arginine levels in the host, impairing proliferation of the parasite. Our findings establish that Toxoplasma usurps the host cell ISR to help secure nutrients that it needs for parasite replication.


Assuntos
Arginina/metabolismo , Fator de Iniciação 2 em Eucariotos/metabolismo , Biossíntese de Proteínas , Proteínas Serina-Treonina Quinases/metabolismo , Toxoplasma/crescimento & desenvolvimento , Toxoplasmose/metabolismo , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Arginina/genética , Transporte Biológico Ativo/genética , Canais de Cálcio/genética , Canais de Cálcio/metabolismo , Fator de Iniciação 2 em Eucariotos/genética , Camundongos , Camundongos Knockout , Proteínas Serina-Treonina Quinases/genética , Canais de Cátion TRPV/genética , Canais de Cátion TRPV/metabolismo , Toxoplasmose/genética , Toxoplasmose/patologia
4.
Int J Mol Sci ; 20(9)2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31064130

RESUMO

HER2 (human epidermal growth factor receptor 2) activation is critical in breast cancer development. HER2 promotes cell proliferation, angiogenesis, survival, and metastasis by activation of PI3K/Akt, Ras/MEK/ERK, and JAK/STAT pathways. However, beyond these signaling molecules, the key proteins underlining HER2-mediated metastasis remain elusive. ATF4 (Activating transcription factor 4), a critical regulator in unfolded protein response (UPR), is implicated in cell migration and tumor metastasis. In this study, we demonstrate that HER2 upregulated ATF4 expression at both mRNA and protein levels, resulting in cell migration increased. In addition, ATF4 upregulated ZEB1 (Zinc finger E-box-binding homeobox 1) and suppressed E-cadherin expression resulting in promoting cell migration. Restoration of E-cadherin expression effectively inhibited HER2- or ATF4-mediated cell migration. In addition, upregulated expression of ATF4 was found in HER2-positive breast cancer specimens. Together, this study demonstrates that ATF4-ZEB1 is important for HER2-mediated cell migration and suggests that ATF4-ZEB1 may be potential therapeutic targets for breast cancer metastasis.


Assuntos
Fator 4 Ativador da Transcrição/genética , Neoplasias da Mama/metabolismo , Caderinas/genética , Movimento Celular , Receptor ErbB-2/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/genética , Fator 4 Ativador da Transcrição/metabolismo , Neoplasias da Mama/genética , Caderinas/metabolismo , Linhagem Celular , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Células MCF-7 , Receptor ErbB-2/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo
5.
Mol Med Rep ; 19(6): 4645-4654, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30957188

RESUMO

Aberrant increase in angiogenesis contributes to the progression of malignant solid tumors. An alternative anti­angiogenesis therapy is critical for cancer, since the current anti­angiogenesis drugs lack specificity for tumor cells. In the present study, the effects and mechanisms of low­intensity pulsed ultrasound (LIPUS) on human umbilical vein endothelial cells (HUVECs) and human microvascular endothelial cells (HMECs) were investigated, and the therapeutic potential of this technology was assessed. HUVECs and HMECs were treated with LIPUS (0.5 MHz; 210 mW/cm2) for 1 min and cultured for 24 h. Flow cytometry and Cell Counting Kit­8 assays demonstrated that LIPUS treatment at a dose of 210 mW/cm2 promoted apoptosis and decreased the viability in HUVECs and HMECs. Real­time cell analysis also revealed that LIPUS did not affect the proliferation or migration of HUVECs. An endothelial cell tube formation assay indicated that LIPUS treatment inhibited the angiogenic ability of HUVECs and HMECs. Furthermore, LIPUS increased the protein levels of the apoptosis­associated cleaved Caspase­3 and decreased the B­cell lymphoma­2 levels. LIPUS increased the phosphorylation of p38 mitogen­activated protein kinase (MAPK), and the levels of endoplasmic reticulum (ER) stress­associated markers, including activating transcription factor­4 (ATF­4) and phosphorylated eukaryotic initiation factor 2α (eIF2α). The p38 inhibitor SB203580 reversed the pro­apoptotic and anti­angiogenic effects of LIPUS in cells. Finally, inhibition of p38 decreased the LIPUS­induced elevation of p­eIF2α and ATF­4 levels. Taken together, these results suggested that LIPUS promoted apoptosis and inhibited angiogenesis in human endothelial cells via the activation of p38 MAPK­mediated ER stress signaling.


Assuntos
Apoptose/efeitos da radiação , Estresse do Retículo Endoplasmático/efeitos da radiação , Células Endoteliais/efeitos da radiação , Neovascularização Patológica/radioterapia , Ondas Ultrassônicas , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Proliferação de Células/efeitos da radiação , Células Endoteliais da Veia Umbilical Humana/efeitos da radiação , Humanos , Linfoma de Células B/radioterapia , Fosforilação , Proteínas Quinases p38 Ativadas por Mitógeno/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo
6.
Int J Mol Sci ; 20(7)2019 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-30959808

RESUMO

: Carnosic acid (CA) is a phytochemical found in some dietary herbs, such as Rosmarinus officinalis L., and possesses antioxidative and anti-microbial properties. We previously demonstrated that CA functions as an activator of nuclear factor, erythroid 2 (NF-E2)-related factor 2 (Nrf2), an oxidative stress-responsive transcription factor in human and rodent cells. CA enhances the expression of nerve growth factor (NGF) and antioxidant genes, such as HO-1 in an Nrf2-dependent manner in U373MG human astrocytoma cells. However, CA also induces NGF gene expression in an Nrf2-independent manner, since 50 µM of CA administration showed striking NGF gene induction compared with the classical Nrf2 inducer tert-butylhydroquinone (tBHQ) in U373MG cells. By comparative transcriptome analysis, we found that CA activates activating transcription factor 4 (ATF4) in addition to Nrf2 at high doses. CA activated ATF4 in phospho-eIF2α- and heme-regulated inhibitor kinase (HRI)-dependent manners, indicating that CA activates ATF4 through the integrated stress response (ISR) pathway. Furthermore, CA activated Nrf2 and ATF4 cooperatively enhanced the expression of NGF and many antioxidant genes while acting independently to certain client genes. Taken together, these results represent a novel mechanism of CA-mediated gene regulation evoked by Nrf2 and ATF4 cooperation.


Assuntos
Fator 4 Ativador da Transcrição/genética , Citoproteção/genética , Diterpenos de Abietano/farmacologia , Regulação da Expressão Gênica , Fator 2 Relacionado a NF-E2/genética , Fator 4 Ativador da Transcrição/metabolismo , Aldeído Redutase/genética , Aldeído Redutase/metabolismo , Antioxidantes/metabolismo , Linhagem Celular Tumoral , Citoproteção/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Hidroquinonas/farmacologia , Modelos Biológicos , Fator 2 Relacionado a NF-E2/metabolismo , Fator de Crescimento Neural/genética , Fator de Crescimento Neural/metabolismo , Transdução de Sinais/efeitos dos fármacos , Estresse Fisiológico/efeitos dos fármacos , Tunicamicina/farmacologia
7.
Nutrients ; 11(3)2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30818817

RESUMO

This study evaluated the effects of vitamin C on osteogenic differentiation and osteoclast formation, and the effects of vitamin C concentration on bone microstructure in ovariectomized (OVX) Wistar rats. Micro-computed tomography analysis revealed the recovery of bone mineral density and bone separation in OVX rats treated with vitamin C. Histomorphometrical analysis revealed improvements in the number of osteoblasts, osteoclasts, and osteocytes; the osteoblast and osteoclast surface per bone surface; and bone volume in vitamin C-treated OVX rats. The vitamin C-treated group additionally displayed an increase in the expression of osteoblast differentiation genes, including bone morphogenetic protein-2, small mothers against decapentaplegic 1/5/8, runt-related transcription factor 2, osteocalcin, and type I collagen. Vitamin C reduced the expression of osteoclast differentiation genes, such as receptor activator of nuclear factor kappa-B, receptor activator of nuclear factor kappa-B ligand, tartrate-resistant acid phosphatase, and cathepsin K. This study is the first to show that vitamin C can inhibit osteoporosis by promoting osteoblast formation and blocking osteoclastogenesis through the activation of wingless-type MMTV integration site family/ß-catenin/activating transcription factor 4 signaling, which is achieved through the serine/threonine kinase and mitogen-activated protein kinase signaling pathways. Therefore, our results suggest that vitamin C improves bone regeneration.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Ácido Ascórbico/farmacologia , Osteoblastos/efeitos dos fármacos , Osteoclastos/efeitos dos fármacos , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Fator 4 Ativador da Transcrição/genética , Ração Animal , Animais , Densidade Óssea , Dieta , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Osteoporose/prevenção & controle , Ovariectomia , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Proteínas Wnt/genética , beta Catenina/genética
8.
Biochim Biophys Acta Mol Cell Res ; 1866(6): 978-991, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30857869

RESUMO

Extracellular amino acid (AA) withdrawal/restriction invokes an integrated stress response (ISR) that induces global suppression of protein synthesis whilst allowing transcription and translation of a select group of genes, whose protein products facilitate cellular adaptation to AA insufficiency. Transcriptional induction of the System A/SNAT2 AA transporter represents a classic adaptation response and crucially depends upon activation of the General Control Nonderepressible-2 kinase/Activating transcription factor 4 (GCN2/ATF4) pathway. However, the ISR may also include additional signalling inputs operating in conjunction or independently of GCN2/ATF4 to upregulate SNAT2. Herein, we show that whilst pharmacological inhibition of MEK-ERK, mTORC1 and p38 MAP kinase signalling has no detectable effect on System A upregulation, inhibitors targeting GSK3 (e.g. SB415286) caused significant repression of the SNAT2 adaptation response. Strikingly, the effects of SB415286 persist in cells in which GSK3α/ß have been stably silenced indicating an off-target effect. We show that SB415286 can also inhibit cyclin-dependent kinases (CDK) and that roscovitine and flavopiridol (two pan CDK inhibitors) are effective repressors of the SNAT2 adaptive response. In particular, our work reveals that CDK7 activity is upregulated in AA-deprived cells in a GCN-2-dependent manner and that a potent and selective CDK7 inhibitor, THZ-1, not only attenuates the increase in ATF4 expression but blocks System A adaptation. Importantly, the inhibitory effects of THZ-1 on System A adaptation are mitigated in cells expressing a doxycycline-inducible drug-resistant form of CDK7. Our data identify CDK7 as a novel component of the ISR regulating System A adaptation in response to AA insufficiency.


Assuntos
Sistema A de Transporte de Aminoácidos/metabolismo , Aminoácidos/deficiência , Quinases Ciclina-Dependentes/metabolismo , Estresse Fisiológico , Fator 4 Ativador da Transcrição/metabolismo , Aminofenóis/farmacologia , Animais , Linhagem Celular , Flavonoides/farmacologia , Células HEK293 , Células HeLa , Humanos , Maleimidas/farmacologia , Fenilenodiaminas/farmacologia , Piperidinas/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Pirimidinas/farmacologia , Ratos , Roscovitina/farmacologia
9.
Int J Mol Sci ; 20(2)2019 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-30669692

RESUMO

Bacteria inhabiting the human gut metabolize microbiota-accessible carbohydrates (MAC) contained in plant fibers and subsequently release metabolic products. Gut bacteria produce hydrogen (H2), which scavenges the hydroxyl radical (•OH). Because H2 diffuses within the cell, it is hypothesized that H2 scavenges cytoplasmic •OH (cyto •OH) and suppresses cellular senescence. However, the mechanisms of cyto •OH-induced cellular senescence and the physiological role of gut bacteria-secreted H2 have not been elucidated. Based on the pyocyanin-stimulated cyto •OH-induced cellular senescence model, the mechanism by which cyto •OH causes cellular senescence was investigated by adding a supersaturated concentration of H2 into the cell culture medium. Cyto •OH-generated lipid peroxide caused glutathione (GSH) and heme shortage, increased hydrogen peroxide (H2O2), and induced cellular senescence via the phosphorylation of ataxia telangiectasia mutated kinase serine 1981 (p-ATMser1981)/p53 serine 15 (p-p53ser15)/p21 and phosphorylation of heme-regulated inhibitor (p-HRI)/phospho-eukaryotic translation initiation factor 2 subunit alpha serine 51 (p-eIF2α)/activating transcription factor 4 (ATF4)/p16 pathways. Further, H2 suppressed increased H2O2 by suppressing cyto •OH-mediated lipid peroxide formation and cellular senescence induction via two pathways. H2 produced by gut bacteria diffuses throughout the body to scavenge cyto •OH in cells. Therefore, it is highly likely that gut bacteria-produced H2 is involved in intracellular maintenance of the redox state, thereby suppressing cellular senescence and individual aging. Hence, H2 produced by intestinal bacteria may be involved in the suppression of aging.


Assuntos
Senescência Celular , Citoplasma/metabolismo , Peróxido de Hidrogênio/metabolismo , Hidrogênio/metabolismo , Radical Hidroxila/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Senescência Celular/efeitos dos fármacos , Inibidor p16 de Quinase Dependente de Ciclina/genética , Inibidor de Quinase Dependente de Ciclina p21/genética , Dano ao DNA , Fator de Iniciação 2 em Eucariotos/metabolismo , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glutationa/metabolismo , Humanos , Hidrogênio/farmacologia , Peróxido de Hidrogênio/farmacologia , Peroxidação de Lipídeos , Masculino , Estresse Oxidativo , Transdução de Sinais/efeitos dos fármacos
10.
Fitoterapia ; 133: 150-158, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30654125

RESUMO

Gambogenic acid (GNA) is one of the main components of Gamboge, and its anti-cancer effects have been well confirmed by previous researches. Nasopharyngeal carcinoma (NPC) has not been thoroughly studied, and the pathogenesis of NPC is unclear. Scientists have neither discovered effective therapies nor achieved a desirable prognosis. Some studies have found that the regulation of intra- and extracellular ion channels hinges directly on cell apoptosis, and treatment with GNA brings changes to the volume-sensitive outwardly rectifying chloride (VSOR Cl-) current of CNE-2Z cells recorded by the patch clamp method. Nevertheless, rarely have any researchers probed into the relevance between this variation and the anti-tumor mechanism of GNA. This paper is suggested that 2.0 µmol/L GNA activates VSOR Cl- currents on CNE-2Z cell membranes and that the activation of VSOR Cl- currents by GNA in CNE-2Z cells is blocked by the chloride channel blockers DIDS (400 µmol/L) and DCPIB (20 µmol/L). MQAE experiment further proves that GNA leads to the opening of chloride ion channel, which in turn results in the efflux of VSOR Cl- current; GNA induces the downregulation of GRP78 and the upregulation of ATF4 and CHOP proteins. These effects are correlated with endoplasmic reticulum (ER) stress. GNA can activate VSOR Cl- channels, leading to ER stress, inducing apoptosis and inhibiting proliferation in CNE-2Z cells.


Assuntos
Apoptose/efeitos dos fármacos , Canais de Cloreto/metabolismo , Carcinoma Nasofaríngeo/metabolismo , Neoplasias Nasofaríngeas/metabolismo , Xantenos/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Linhagem Celular Tumoral , Cloretos/análise , Estresse do Retículo Endoplasmático , Garcinia/química , Proteínas de Choque Térmico/metabolismo , Humanos , Carcinoma Nasofaríngeo/tratamento farmacológico , Neoplasias Nasofaríngeas/tratamento farmacológico , Fator de Transcrição CHOP/metabolismo
11.
Toxicology ; 414: 1-13, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30605698

RESUMO

The heavy metal cadmium (Cd) is well known to be neurotoxic. Studies have shown that apoptosis plays an essential role in Cd-induced brain injury; however, the mechanisms underlying this injury accompanied by apoptosis have yet to be elucidated. The endoplasmic reticulum (ER) stress plays a key part in the regulation of apoptosis. ER stress is defined as accumulation of unfolded or misfolded proteins in the ER. Here, we demonstrated the role of ER stress on Cd-evoked apoptosis in neuronal cells, as well as the neuroprotective effects of the antioxidant alpha-lipoic acid (α-LA) on Cd-induced ER stress and neuronal injury. In vitro, we observed that Cd activated ER associated proteins via the eIF2α-ATF4 pathway in primary rat cerebral cortical neurons. Furthermore, the ER-stress inhibitor salubrinal blocked the dephosphorylation of eukaryotic translation initiation factor 2α (eIF2α) and significantly reduced the induction of ER stress marker CHOP, the increase of the B-cell lymphoma-2 associate X protein (Bax)/B-cell lymphoma-2 (Bcl-2) ratio, and apoptosis induced by Cd. In addition, Z-ATAD-FMK (a caspase-12 inhibitor) counteracted the Cd-induced activation of caspase-12 and -3, and apoptosis. These in vitro results collectively suggested that ER stress was required for Cd-induced neuronal apoptosis. Importantly, α-LA inhibited the activation of the ER stress eIF2α-ATF4 pathway, the increase of the Bax/Bcl-2 ratio, the activation of caspase-12 and -3, and the apoptosis induced by Cd. In vivo, we also found that the administration of α-LA alleviated Cd-induced neuronal injury, inhibited the activation of the ER stress eIF2α-ATF4 pathway, restored the Bax/Bcl-2 ratio, and prevented the activation of caspase-12 and -3. Taken together, our results demonstrated that Cd triggered protein changes in the ER accompanied by apoptosis via the eIF2α-ATF4 signaling pathway in the neuronal cells of rats, both in vitro and in vivo. Furthermore, we demonstrated for the first time that α-LA protected neurons from Cd-induced injury partly by inhibiting ER stress in rat cerebral cortical neurons.


Assuntos
Acetatos/toxicidade , Fator 4 Ativador da Transcrição/metabolismo , Apoptose/efeitos dos fármacos , Cádmio/toxicidade , Córtex Cerebral/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/metabolismo , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Síndromes Neurotóxicas/prevenção & controle , Ácido Tióctico/farmacologia , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Células Cultivadas , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Citoproteção , Feminino , Neurônios/metabolismo , Neurônios/patologia , Síndromes Neurotóxicas/metabolismo , Síndromes Neurotóxicas/patologia , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
12.
Int J Mol Med ; 43(1): 345-357, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30431065

RESUMO

MicroRNA (miR)­214 has been demonstrated to suppress gluconeogenesis by targeting activating transcription factor 4 (ATF4), which regulates gluconeogenesis by affecting the transcriptional activity of forkhead box protein O1 (FoxO1). Our previous study revealed that the upregulation of maternally expressed gene 3 (MEG3), a long noncoding RNA, enhanced hepatic insulin resistance via increased FoxO1 expression. The present study aimed to explore whether miR­214 and ATF4 were involved in the MEG3­mediated increase of FoxO1 expression. MEG3, miR­214 and ATF4 expression were examined by reverse transcription quantitative polymerase chain reaction and western blot analysis. The interaction among MEG3, miR­214 and ATF4 was analysed using the luciferase reporter assay. MEG3­targeting small interference RNAs were injected into high­fat diet (HFD)­fed mice to verify the role of MEG3 in hepatic insulin resistance in vivo. MEG­3 and ATF4 were demonstrated to be upregulated and miR­214 was indicated to be downregulated in the livers of HFD­fed and ob/ob mice. In mouse primary hepatocytes, palmitate time­dependently increased MEG3 and ATF4 but decreased miR­214 expression levels. Furthermore, MEG3 served as a competing endogenous RNA (ceRNA) for miR­214 to facilitate ATF4 expression, while miR­214 inhibition and ATF4 overexpression reversed the MEG3 knockdown­mediated decrease in the expression of FoxO1 and FoxO1­downstream targets phosphoenolpyruvate carboxykinase and glucose­6­phosphatase catalytic subunit. In HFD­fed mice, MEG3 knockdown substantially improved impaired glucose and insulin tolerance, while downregulating HFD­induced ATF4 expression and upregulating HFD­suppressed miR­214 expression. In conclusion, MEG3 promoted hepatic insulin resistance by serving as a ceRNA of miR­214 to facilitate ATF4 expression. These data provide insight into the molecular mechanism of MEG3 involvement in the development of type 2 diabetes mellitus.


Assuntos
Fator 4 Ativador da Transcrição/genética , Regulação da Expressão Gênica , Resistência à Insulina , Fígado/metabolismo , Fígado/patologia , MicroRNAs/metabolismo , RNA Longo não Codificante/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Animais , Dieta Hiperlipídica , Regulação para Baixo/genética , Proteína Forkhead Box O1/metabolismo , Técnicas de Silenciamento de Genes , Glucose/metabolismo , Glucose-6-Fosfatase/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Obesos , MicroRNAs/genética , Ácido Palmítico/farmacologia , Fosfoenolpiruvato Carboxiquinase (ATP)/metabolismo , RNA Longo não Codificante/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Regulação para Cima/genética
13.
Biochim Biophys Acta Mol Cell Res ; 1866(4): 713-726, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30528975

RESUMO

Lead (Pb) is a known nephrotoxicant that causes damage to proximal tubular cells. PERK pathway plays an important role in the pathogenesis of renal diseases, but its role in Pb-induced nephrotoxicity remains largely unknown. In this study, data showed that Pb could induce ER stress as shown by increased phosphorylation of PERK with subsequent activation of the eIF2α-ATF4-CHOP axis in primary rat proximal tubular (rPT) cells, indicating the activation of PERK-eIF2α-ATF4-CHOP pathway due to excessive ER stress. Pb-activated PERK pathway can be effectively inhibited by 4-phenylbutyric acid and PERK gene silencing, respectively; whereas continuously up-regulated by tunicamycin (TM) treatment. Moreover, Pb-induced apoptosis and inhibition of autophagic flux in rPT cells were significantly augmented and aggravated by co-treatment with TM, respectively. Pharmacological or genetic inhibition of the PERK pathway results in alleviation of apoptosis and restoration of autophagy inhibition in Pb-exposed rPT cells. Mechanistically, activation of PERK-eIF2α-ATF4-CHOP axis triggered by excessive ER stress in rPT cells leads to Pb-induced apoptosis and blockage of autophagic flux, resulting in nephrotoxicity.


Assuntos
Estresse do Retículo Endoplasmático , Túbulos Renais Proximais/efeitos dos fármacos , Chumbo/toxicidade , eIF-2 Quinase/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Células Cultivadas , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Fator de Iniciação 2 em Eucariotos/metabolismo , Túbulos Renais Proximais/enzimologia , Túbulos Renais Proximais/metabolismo , Fenilbutiratos/farmacologia , Ratos Sprague-Dawley , Fator de Transcrição CHOP/metabolismo , Tunicamicina/farmacologia , eIF-2 Quinase/genética
14.
Cell Physiol Biochem ; 51(6): 2955-2971, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30562747

RESUMO

BACKGROUND/AIMS: Intermittent hypoxia (IH) causes apoptosis in pancreatic ß-cells, but the potential mechanisms remain unclear. Endoplasmic reticulum (ER) stress, autophagy, and apoptosis are interlocked in an extensive crosstalk. Thus, this study aimed to investigate the contributions of ER stress and autophagy to IH-induced pancreatic ß-cell apoptosis. METHODS: We established animal and cell models of IH, and then inhibited autophagy and ER stress by pharmacology and small interfering RNA (siRNA) in INS-1 cells and rats. The levels of biomarkers for autophagy, ER stress, and apoptosis were evaluated by immunoblotting and immunofluorescence. The number of autophagic vacuoles was observed by transmission electron microscopy. RESULTS: IH induced autophagy activation both in vivo and in vitro, as evidenced by increased autophagic vacuole formation and LC3 turnover, and decreased SQSTM1 level. The levels of ER-stress-related proteins, including GRP78, CHOP, caspase 12, phosphorylated (p)-protein kinase RNA-like ER kinase (PERK), p-eIF2α, and activating transcription factor 4 (ATF4) were increased under IH conditions. Inhibition of ER stress with tauroursodeoxycholic acid or 4-phenylbutyrate partially blocked IH-induced autophagy in INS-1 cells. Furthermore, inhibition of PERK with GSK2606414 or siRNA blocked the ERstress-related PERK/eIF2α/ATF4 signaling pathway and inhibited autophagy induced by IH, which indicates that IH-induced autophagy activation is dependent on this signaling pathway. Promoting autophagy with rapamycin alleviated IH-induced apoptosis, whereas inhibition of autophagy with chloroquine or autophagy-related gene (Atg5 and Atg7) siRNA aggravated pancreatic ß-cell apoptosis caused by IH. CONCLUSION: IH induces autophagy activation through the ER-stress-related PERK/eIF2α/ATF4 signaling pathway, which is a protective response to pancreatic ß-cell apoptosis caused by IH.


Assuntos
Fator 4 Ativador da Transcrição/metabolismo , Autofagia , Estresse do Retículo Endoplasmático , Fator de Iniciação 2 em Eucariotos/metabolismo , Hipóxia/metabolismo , Células Secretoras de Insulina/citologia , eIF-2 Quinase/metabolismo , Animais , Apoptose , Hipóxia Celular , Células Cultivadas , Células Secretoras de Insulina/metabolismo , Masculino , Ratos Sprague-Dawley , Transdução de Sinais
15.
Int J Mol Sci ; 19(12)2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30551605

RESUMO

A variety of cellular stresses lead to global translation attenuation due to phosphorylation of the alpha subunit of eukaryotic initiation factor 2 (eIF2), which decreases the availability of the eIF2-GTP-Met-tRNAi ternary complex. However, a subset of mRNAs continues to be translated by non-canonical mechanisms under these conditions. In fact, although translation initiation of activating transcription factor 4 (ATF4) is normally repressed by an upstream open reading frame (uORF), a decreased availability of ternary complex leads to increased translation of the main ATF4-coding ORF. We show here that siRNA-mediated depletion of eIF5B-which can substitute for eIF2 in delivering Met-tRNAi-leads to increased levels of ATF4 protein in mammalian cells. This de-repression is not due to phosphorylation of eIF2α under conditions of eIF5B depletion. Although eIF5B depletion leads to a modest increase in the steady-state levels of ATF4 mRNA, we show by polysome profiling that the depletion of eIF5B enhances ATF4 expression primarily at the level of translation. Moreover, eIF5B silencing increases the expression of an ATF4-luciferase translational reporter by a mechanism requiring the repressive uORF2. Further experiments suggest that eIF5B cooperates with eIF1A and eIF5, but not eIF2A, to facilitate the uORF2-mediated repression of ATF4 translation.


Assuntos
Fator 4 Ativador da Transcrição/genética , Endonucleases/metabolismo , Fator de Iniciação 1 em Eucariotos/metabolismo , Fatores de Iniciação em Eucariotos/metabolismo , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas de Ligação a RNA/metabolismo , DNA Polimerase Dirigida por RNA/metabolismo , Fator 4 Ativador da Transcrição/metabolismo , Linhagem Celular , Células HEK293 , Humanos , Fatores de Iniciação de Peptídeos/genética , Fosforilação , Polirribossomos/metabolismo , Biossíntese de Proteínas , RNA Interferente Pequeno/farmacologia , Proteínas de Ligação a RNA/genética
16.
PLoS One ; 13(12): e0208993, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30592731

RESUMO

Endoplasmic reticulum (ER) stress results from imbalances in unfolded/misfolded proteins, contributing to a wide variety of human diseases. To better understand the mechanisms involved in the cellular response to ER stress in cardiomyocytes, we previously conducted a genome-wide screening in an in vitro ER stress model of rat cardiomyocytes, which highlighted amino acid transporter heavy chain, member 2 (SLC3A2) as an important factor in ER stress. In the present study, we characterized the role of SLC3A2 during the unfolded protein response (UPR), as one of the primary pathways activated during ER stress. First, we confirmed the induction of Slc3a2 mRNA expression following treatment with various ER stress inducers in rat cardiomyocytes (H9C2) and neural cells (PC12). Knockdown of Slc3a2 expression with small interfering RNA (siRNA) revealed that the encoded protein functions upstream of three important UPR proteins: ATF4, ATF6, and XBP1. siRNA-mediated knockdown of both SLC3A2 and mammalian target of rapamycin 1 (mTOR1) revealed that mTOR1 acts as a mediator between SLC3A2 and the UPR. RNA sequencing was then performed to gain a more thorough understanding of the function of SLC3A2, which identified 23 highly differentially regulated genes between the control and knockdown cell lines, which were related to the UPR and amino acid transport. Notably, flow cytometry further showed that SLC3A2 inhibition also enhanced the apoptosis of rat cardiomyocytes. Taken together, these results highlight SLC3A2 as a complex, multifunctional signaling protein that acts upstream of well-known UPR proteins with anti-apoptotic properties, suggesting its potential as a therapeutic target for ER stress-related diseases.


Assuntos
Apoptose , Estresse do Retículo Endoplasmático , Cadeia Pesada da Proteína-1 Reguladora de Fusão/metabolismo , Resposta a Proteínas não Dobradas , Fator 4 Ativador da Transcrição/antagonistas & inibidores , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Regulação para Baixo , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Cadeia Pesada da Proteína-1 Reguladora de Fusão/antagonistas & inibidores , Cadeia Pesada da Proteína-1 Reguladora de Fusão/genética , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , Células PC12 , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Ratos , Serina-Treonina Quinases TOR/metabolismo , Tapsigargina/farmacologia , Resposta a Proteínas não Dobradas/efeitos dos fármacos , Proteína 1 de Ligação a X-Box/antagonistas & inibidores , Proteína 1 de Ligação a X-Box/genética , Proteína 1 de Ligação a X-Box/metabolismo
17.
Cell Physiol Biochem ; 49(2): 595-609, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30165357

RESUMO

BACKGROUND/AIMS: Spinal cord injury (SCI) is a serious global problem that leads to permanent motor and sensory deficits. This study explores the anti-apoptotic and neuroprotective effects of the natural extract ß-elemene in vitro and in a rat model of SCI. METHODS: CCK-8 assay was used to evaluate cell viability and lactate dehydrogenase assay was used to evaluate cytotoxicity. A model of cell injury was established using cobalt chloride. Apoptosis was evaluated using a fluorescence-activated cell sorting assay of annexin V-FITC and propidium iodide staining. A rat SCI model was created via the modified Allen's method and Basso, Beattie, and Bresnahan (BBB) scores were used to assess locomotor function. Inflammatory responses were assessed via enzyme-linked immunosorbent assay (ELISA). Apoptotic and surviving neurons in the ventral horn were respectively observed via terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and Nissl staining. Western blotting was used to measure protein expression. RESULTS: ß-elemene (20 µg/ml) promoted cell viability by activating phosphorylation of the PI3K-AKT-mTOR pathway. ß-elemene reduced CoCl2-induced cellular death and apoptosis by suppressing the expression levels of CHOP, cleaved-caspase 12, 78-kilodalton glucose-regulated protein, cleaved-caspase 3, and the Bax/Bcl-2 ratio. In the rat model of SCI, Nissl and TUNEL staining showed that ß-elemene promoted motor neuron survival and reduced neuronal apoptosis in the spinal cord ventral horn. BBB scores showed that ß-elemene significantly promoted locomotor behavioral recovery after SCI. In addition, ß-elemene reduced the ELISA-detected secretion of interleukin (IL)-6 and IL-1ß. CONCLUSION: ß-elemene reduces neuronal apoptosis by alleviating endoplasmic reticulum stress in vitro and in vivo. In addition, ß-elemene promotes locomotor function recovery and tissue repair in SCI rats. Thus, our study provides a novel encouraging strategy for the potential treatment of ß-elemene in SCI patients.


Assuntos
Apoptose/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Recuperação de Função Fisiológica/efeitos dos fármacos , Sesquiterpenos/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Animais , Células Cultivadas , Cobalto/farmacologia , Feminino , Proteínas de Choque Térmico/metabolismo , Neurônios/citologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Ratos , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos , Traumatismos da Medula Espinal/metabolismo , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/veterinária , Serina-Treonina Quinases TOR/metabolismo , Fator de Transcrição CHOP/metabolismo , eIF-2 Quinase/metabolismo
18.
Lipids Health Dis ; 17(1): 183, 2018 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-30064425

RESUMO

BACKGROUND: Lipotoxicity plays an important role in the pathogenesis of kidney injury. Our previous study demonstrated that activation of local renin-angiotensin system (RAS) was involved in saturated free fatty acids palmitic acid (PA)-induced tubular cell injuries. The current study aims to investigate whether suppression of RAS by combination of direct renin inhibitor aliskiren and noncanonical RAS pathway chymase inhibitor chymostatin attenuates PA or cholesterol induced-endoplasmic reticulum stress (ER stress) and apopotosis in cultured human proximal tubular HK2 cells. METHODS: HK2 cells were treated with saturated fatty acid PA (0.6 mM) for 24 h or cholesterol (10 µg/ml) for 6d with or without chymostatin and/or aliskiren. Expressions of the ER stress associated proteins and apoptosis markers were detected by western blotting. The mRNA levels of RAS components were measured by real-time qPCR. RESULTS: Combination treatment of chymostatin and aliskiren markedly suppressed PA or cholesterol-induced ER stress, as reflected by increased BiP, IRE1α, phosphorylated-eIF2α and ATF4 as well as proapoptotic transcription factor CHOP. The ratio of Bax/Bcl-2 and cleaved caspase-3, two markers of apoptosis were upregulated by PA or cholesterol treatment. PA treatment was also associated with increased levels of angiotensinogen and angiotensin type 1 receptor (AT1R) mRNA expression. Combination treatment of chymostatin and aliskiren markedly suppressed PA or cholesterol-induced ER stress and apoptosis. The protective effect of two inhibitors was also observed in primary cultured cortical tubular cells treated with PA. In contrast, chymostatin and/or aliskiren failed to prevent ER stress induced by tunicamycin. CONCLUSIONS: These results suggested that combination treatment of chymostatin and aliskiren attenuates lipid-induced renal tubular cell injury, likely through suppressing activation of intracellular RAS.


Assuntos
Amidas/farmacologia , Anti-Hipertensivos/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Células Epiteliais/efeitos dos fármacos , Fumaratos/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Oligopeptídeos/farmacologia , Inibidores de Serino Proteinase/farmacologia , Fator 4 Ativador da Transcrição/genética , Fator 4 Ativador da Transcrição/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Linhagem Celular Transformada , Colesterol/farmacologia , Combinação de Medicamentos , Sinergismo Farmacológico , Endorribonucleases/genética , Endorribonucleases/metabolismo , Células Epiteliais/citologia , Células Epiteliais/metabolismo , Fator de Iniciação 2 em Eucariotos/genética , Fator de Iniciação 2 em Eucariotos/metabolismo , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Túbulos Renais Proximais/citologia , Túbulos Renais Proximais/efeitos dos fármacos , Túbulos Renais Proximais/metabolismo , Ácido Palmítico/antagonistas & inibidores , Ácido Palmítico/farmacologia , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Receptor Tipo 1 de Angiotensina/genética , Receptor Tipo 1 de Angiotensina/metabolismo , Transdução de Sinais , Fator de Transcrição CHOP/genética , Fator de Transcrição CHOP/metabolismo , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/metabolismo
19.
Nutrients ; 10(7)2018 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-29958415

RESUMO

Oxidative stress (OS) and endoplasmic reticulum stress (ERS) are the major factors underlying photoreceptor degeneration. Lutein, RR-zeaxanthin (3R,3’R-zeaxanthin) and RS (meso)-zeaxanthin (3R,3’S-RS- zeaxanthin) (L/Zi) could protect against cell damage by ameliorating OS in retina. In this study, we examined the effect of L/Zi supplementation in a mouse model of photoreceptor degeneration and investigated whether the treatment of L/Zi ameliorated OS and ERS. BALB/cJ mice after light exposure were used as the animal model. The protective effects of L/Zi were observed by electroretinography (ERG) and terminal deoxyuridine triphosphate nick-end labeling (TUNEL) analysis. The underlying mechanisms related to OS and ERS were explored by Western blotting. After L/Zi treatment, the ERG amplitudes were significantly higher, and the number of TUNEL-positive cells was significantly reduced compared to that of the vehicle group. Western blotting results revealed that OS was ameliorated according to the significant downregulation of phosphorylated c-Jun N-terminal kinase (p-JNK), and significant upregulation of nuclear factor erythroid 2-related factor 2 (Nrf2). In addition, ERS was reduced according to the significant downregulation of 78 kDa glucose-regulated protein (GRP78), phosphorylated protein kinase RNA-like endoplasmic reticulum kinase (p-PERK), activating transcription factor 4 (ATF4) and activating transcription factor (ATF6). Our data shows that L/Zi provided functional and morphological preservation of photoreceptors against light damage, which is probably related to its mitigation of oxidative and endoplasmic reticulum stress.


Assuntos
Antioxidantes/farmacologia , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Luz , Luteína/farmacologia , Estresse Oxidativo/efeitos dos fármacos , Células Fotorreceptoras de Vertebrados/efeitos dos fármacos , Doenças Retinianas/prevenção & controle , Zeaxantinas/farmacologia , Fator 4 Ativador da Transcrição/metabolismo , Fator 6 Ativador da Transcrição/metabolismo , Animais , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Eletrorretinografia , Proteínas de Choque Térmico/metabolismo , Isomerismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Fator 2 Relacionado a NF-E2/metabolismo , Fosforilação , Células Fotorreceptoras de Vertebrados/metabolismo , Células Fotorreceptoras de Vertebrados/patologia , Doenças Retinianas/metabolismo , Doenças Retinianas/patologia , Transdução de Sinais/efeitos dos fármacos , eIF-2 Quinase/metabolismo
20.
Cell Physiol Biochem ; 47(5): 1936-1950, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29972819

RESUMO

BACKGROUND/AIMS: Endoplasmic reticulum (ER) stress and unfolded protein response (UPR) are involved in hematopoietic differentiation. However, the mechanistic linkage between ER stress/UPR and hematopoietic differentiation remains unclear. METHODS: We used bipotent HL-60 cells as an in vitro hematopoietic differentiation system to investigate the role of ER stress and UPR activity in neutrophil and macrophage differentiation. RESULTS: The in vitro differentiation analysis revealed that ER stress decreased during both neutrophil and macrophage differentiations, and the activities of PERK and ATF6 were decreased and that of IRE1α was increased during neutrophil differentiation in a stage-specific manner. By contrast, the activities of ATF6 and ATF4 decreased during macrophage differentiation. When the cells were treated with oligomycin, the expression of CD11b, a myelocytic differentiation marker, and morphological differentiation were suppressed, and XBP-1 activation was inhibited during neutrophil differentiation, whereas CD11b expression was maintained, and morphological differentiation was not obviously affected during macrophage differentiation. CONCLUSION: In this study, we demonstrated that neutrophil differentiation is regulated by ER stress/UPR that is supported by mitochondrial ATP supply, in which IRE1α-XBP1 activation is essential. Our findings provide the evidence that mitochondrial energy metabolism may play a critical role in neutrophil differentiation.


Assuntos
Diferenciação Celular/fisiologia , Metabolismo Energético/fisiologia , Mitocôndrias/metabolismo , Neutrófilos/metabolismo , Resposta a Proteínas não Dobradas/fisiologia , Fator 4 Ativador da Transcrição/metabolismo , Fator 6 Ativador da Transcrição/metabolismo , Antígeno CD11b/metabolismo , Células HL-60 , Humanos , Neutrófilos/citologia , Proteína 1 de Ligação a X-Box/metabolismo , eIF-2 Quinase/metabolismo
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