Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 452
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
2.
PLoS Pathog ; 15(9): e1008065, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31557263

RESUMO

Most known thioredoxin-type proteins (Trx) participate in redox pathways, using two highly conserved cysteine residues to catalyze thiol-disulfide exchange reactions. Here we demonstrate that the so far unexplored Trx2 from African trypanosomes (Trypanosoma brucei) lacks protein disulfide reductase activity but functions as an effective temperature-activated and redox-regulated chaperone. Immunofluorescence microscopy and fractionated cell lysis revealed that Trx2 is located in the mitochondrion of the parasite. RNA-interference and gene knock-out approaches showed that depletion of Trx2 impairs growth of both mammalian bloodstream and insect stage procyclic parasites. Procyclic cells lacking Trx2 stop proliferation under standard culture conditions at 27°C and are unable to survive prolonged exposure to 37°C, indicating that Trx2 plays a vital role that becomes augmented under heat stress. Moreover, we found that Trx2 contributes to the in vivo infectivity of T. brucei. Remarkably, a Trx2 version, in which all five cysteines were replaced by serine residues, complements for the wildtype protein in conditional knock-out cells and confers parasite infectivity in the mouse model. Characterization of the recombinant protein revealed that Trx2 can coordinate an iron sulfur cluster and is highly sensitive towards spontaneous oxidation. Moreover, we discovered that both wildtype and mutant Trx2 protect other proteins against thermal aggregation and preserve their ability to refold upon return to non-stress conditions. Activation of the chaperone function of Trx2 appears to be triggered by temperature-mediated structural changes and inhibited by oxidative disulfide bond formation. Our studies indicate that Trx2 acts as a novel chaperone in the unique single mitochondrion of T. brucei and reveal a new perspective regarding the physiological function of thioredoxin-type proteins in trypanosomes.


Assuntos
Proteínas de Protozoários/metabolismo , Tiorredoxinas/metabolismo , Trypanosoma brucei brucei/metabolismo , Animais , Técnicas de Silenciamento de Genes , Genes de Protozoários , Humanos , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Chaperonas Moleculares/antagonistas & inibidores , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Mutação , Oxirredução , Proteínas de Protozoários/antagonistas & inibidores , Proteínas de Protozoários/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Tiorredoxinas/antagonistas & inibidores , Tiorredoxinas/genética , Trypanosoma brucei brucei/genética , Trypanosoma brucei brucei/patogenicidade
3.
Dis Markers ; 2019: 6131548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31379979

RESUMO

Breast cancer is one of the most serious cancers worldwide, and chemotherapy resistance frequently drives cancer progression. Triple-negative breast cancer (TNBC) has a high recurrence rate and poor prognosis given its resistance to chemotherapy. In our previous study, we found a remarkable abnormal methylation modification of the PCDHGB7 gene in breast cancer. However, the roles of PCDHGB7 in the progression and treatment of breast cancer are unclear. In this study, we examined the effects of PCDHGB7 on the sensitivity of TNBC cells to carboplatin and investigated the underlying mechanism. By knocking down and overexpressing PCDHGB7 in HS578T and BT549 cells, we confirmed that PCDHGB7 increases TNBC cell chemosensitivity to carboplatin. Mechanistically, we found that PCDHGB7 negatively regulates the expression of HSPA9, uplifting its inhibition on P53 translocation and caspase-3 activation. Thus, we demonstrated that PCDHGB7 increases chemosensitivity of TNBC cells to carboplatin by inhibiting HSPA9 via inducing apoptosis. PCDHGB7 and HSPA9 represent potential therapeutic targets for chemosensitivity in breast cancer.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias da Mama/tratamento farmacológico , Caderinas/metabolismo , Carboplatina/farmacologia , Resistencia a Medicamentos Antineoplásicos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteínas Mitocondriais/antagonistas & inibidores , Antineoplásicos/farmacologia , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Caderinas/genética , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Células Tumorais Cultivadas
4.
Biochem J ; 476(11): 1585-1604, 2019 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-31036718

RESUMO

Mitochondria play a central role in the maintenance of the naive state of embryonic stem cells. Many details of the mechanism remain to be fully elucidated. Solute carrier family 25 member 36 (Slc25a36) might regulate mitochondrial function through transporting pyrimidine nucleotides for mtDNA/RNA synthesis. Its physical role in this process remains unknown; however, Slc25a36 was recently found to be highly expressed in naive mouse embryonic stem cells (mESCs). Here, the function of Slc25a36 was characterized as a maintenance factor of mESCs pluripotency. Slc25a36 deficiency (via knockdown) has been demonstrated to result in mitochondrial dysfunction, which induces the differentiation of mESCs. The expression of key pluripotency markers (Pou5f1, Sox2, Nanog, and Utf1) decreased, while that of key TE genes (Cdx2, Gata3, and Hand1) increased. Cdx2-positive cells emerged in Slc25a36-deficient colonies under trophoblast stem cell culture conditions. As a result of Slc25a36 deficiency, mtDNA of knockdown cells declined, leading to impaired mitochondria with swollen morphology, decreased mitochondrial membrane potential, and low numbers. The key transcription regulators of mitochondrial biogenesis also decreased. These results indicate that mitochondrial dysfunction leads to an inability to support the pluripotency maintenance. Moreover, down-regulated glutathione metabolism and up-regulated focal adhesion reinforced and stabilized the process of differentiation by separately enhancing OCT4 degradation and promoting cell spread. This study improves the understanding of the function of Slc25a36, as well as the relationship of mitochondrial function with naive pluripotency maintenance and stem cell fate decision.


Assuntos
Glutationa/metabolismo , Proteínas Mitocondriais/metabolismo , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Proteínas de Transporte de Nucleotídeos/metabolismo , Animais , Fator de Transcrição CDX2/metabolismo , Diferenciação Celular/genética , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Adesões Focais , Regulação da Expressão Gênica , Técnicas de Silenciamento de Genes , Camundongos , Mitocôndrias/metabolismo , Mitocôndrias/ultraestrutura , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Proteínas de Transporte de Nucleotídeos/antagonistas & inibidores , Proteínas de Transporte de Nucleotídeos/genética , Fator 3 de Transcrição de Octâmero/metabolismo
5.
Biofactors ; 45(5): 631-640, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31136038

RESUMO

Cancer metastasis represents a multistep process, including alteration of cell adhesion/motility in the microenvironment and sustained angiogenesis, which is essential for supporting cancer growth in tissues that are distant from the primary tumor. There is growing evidence suggesting that heat shock proteins (HSPs) (also known as heat stress proteins), which constitute a family of stress-inducible proteins, may be involved in the pathogenesis of cancer. Curcumin (diferuloylmethane) is a potent anti-inflammatory, antioxidant, antimicrobial, and antitumor agent. Curcumin has been shown to regulate different members of HSPs including HSP27, HSP40, HSP60, HSP70, and HSP90 in cancer. Here, we present extent findings suggesting that curcumin may act as a potential therapeutic agent for the treatment of cancer through its regulation of HSPs.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Curcumina/farmacologia , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Proteínas de Neoplasias/genética , Neoplasias/tratamento farmacológico , Neovascularização Patológica/prevenção & controle , Chaperonina 60/antagonistas & inibidores , Chaperonina 60/genética , Chaperonina 60/metabolismo , Proteínas de Choque Térmico HSP40/agonistas , Proteínas de Choque Térmico HSP40/genética , Proteínas de Choque Térmico HSP40/metabolismo , Proteínas de Choque Térmico HSP70/agonistas , Proteínas de Choque Térmico HSP70/genética , Proteínas de Choque Térmico HSP70/metabolismo , Proteínas de Choque Térmico HSP90/antagonistas & inibidores , Proteínas de Choque Térmico HSP90/genética , Proteínas de Choque Térmico HSP90/metabolismo , Proteínas de Choque Térmico/antagonistas & inibidores , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Metástase Linfática , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Chaperonas Moleculares/antagonistas & inibidores , Chaperonas Moleculares/genética , Chaperonas Moleculares/metabolismo , Proteínas de Neoplasias/agonistas , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/metabolismo , Neoplasias/genética , Neoplasias/metabolismo , Neoplasias/patologia , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Neovascularização Patológica/patologia , Transdução de Sinais , Microambiente Tumoral/efeitos dos fármacos , Microambiente Tumoral/genética
6.
BMC Res Notes ; 12(1): 293, 2019 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-31133049

RESUMO

OBJECTIVE: Recombinant immunotoxins (RITs) are antibody-toxin fusion proteins that can selectively eliminate populations of cells expressing specific surface receptors. They are in evaluation as therapeutic agents for cancer. RITs based on Pseudomonas exotoxin A (PE) are in use clinically for the treatment of hairy cell leukemia, and under trial for the treatment of other cancers. In an effort to improve the efficacy of PE-based RITs, we evaluated the potential of combination therapy with several common antibiotics (tetracycline, chloramphenicol, streptomycin, linezolid, fusidic acid, and kanamycin) on human cell lines HEK293, OVCAR8, and CA46. Antibiotics were selected based on their potential to inhibit mitochondrial protein synthesis and disrupt energy metabolism in cancer cells. RESULTS: Tetracycline, chloramphenicol, linezolid, and fusidic acid alone killed cultured human cells at high concentrations. At high but nontoxic concentrations of each antibiotic, only chloramphenicol treatment of the Burkitt's lymphoma cell line CA46 showed enhanced cytotoxicity when paired with an anti-transferrin receptor/PE RIT. This result, however, could not be replicated in additional Burkitt's lymphoma cell lines Ramos and Raji. Although the six antibiotics we tested are not promising candidates for RIT combination therapy, we suggest that fusidic acid could be considered independently as a potential cancer therapeutic.


Assuntos
ADP Ribose Transferases/farmacologia , Antibacterianos/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Toxinas Bacterianas/farmacologia , Exotoxinas/farmacologia , Ácido Fusídico/farmacologia , Imunotoxinas/farmacologia , Fatores de Virulência/farmacologia , Anticorpos Monoclonais/química , Anticorpos Monoclonais/farmacologia , Linhagem Celular Tumoral , Cloranfenicol/farmacologia , Células Epiteliais/efeitos dos fármacos , Células Epiteliais/metabolismo , Células Epiteliais/patologia , Células HEK293 , Humanos , Concentração Inibidora 50 , Canamicina/farmacologia , Linezolida/farmacologia , Linfócitos/efeitos dos fármacos , Linfócitos/patologia , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/biossíntese , Proteínas Recombinantes de Fusão/farmacologia , Estreptomicina/farmacologia , Tetraciclina
7.
J Pharmacol Exp Ther ; 370(1): 25-34, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31010844

RESUMO

Disease relapse in B-cell acute lymphoblastic leukemia (ALL), either due to development of acquired resistance after therapy or because of de novo resistance, remains a therapeutic challenge. In the present study, we have developed a cytarabine (Ara-C)-resistant REH cell line (REH/Ara-C) as a chemoresistance model. REH/Ara-C 1) was not crossresistant to vincristine or methotrexate; 2) showed a similar proliferation rate and cell surface marker expression as parental REH; 3) demonstrated decreased chemotaxis toward bone marrow stromal cells; and 4) expressed higher transcript levels of cytidine deaminase (CDA) and mitoNEET (CISD1) than the parental REH cell line. Based on these findings, we tested NL-1, a mitoNEET inhibitor, which induced a concentration-dependent decrease in cell viability with a comparable IC50 value in REH and REH/Ara-C. Furthermore, NL-1 decreased cell viability in six different ALL cell lines and showed inhibitory activity in a hemosphere assay. NL-1 also impaired the migratory ability of leukemic cells, irrespective of the chemoattractant used, in a chemotaxis assay. More importantly, NL-1 showed specific activity in inducing death in a drug-resistant population of leukemic cells within a coculture model that mimicked the acquired resistance and de novo resistance observed in the bone marrow of relapsed patients. Subsequent studies indicated that NL-1 mediates autophagy, and inhibition of autophagy partially decreased NL-1-induced tumor cell death. Finally, NL-1 showed antileukemic activity in an in vivo mouse ALL model. Taken together, our study demonstrates that mitoNEET has potential as a novel antileukemic drug target in treatment refractory or relapsed ALL.


Assuntos
Antineoplásicos/farmacologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Leucemia-Linfoma Linfoblástico de Células Precursoras/patologia , Autofagia/efeitos dos fármacos , Linhagem Celular Tumoral , Quimiotaxia/efeitos dos fármacos , Citarabina/farmacologia , Descoberta de Drogas , Humanos , Ligantes , Proteínas Mitocondriais/antagonistas & inibidores , Recidiva
8.
Neurosci Lett ; 705: 7-13, 2019 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-30995519

RESUMO

The discovery of rare familial monogenic forms of early-onset Parkinson's disease has led to the identification of a mitochondrial quality control process as a key player in this disease. Loss-of-function mutations in the genes encoding PINK1 or Parkin result in insufficient removal of dysfunctional mitochondria through autophagy, a process termed mitophagy. Understanding the mechanism of this process and the function of its two key players, PINK1 and Parkin, has led to the discovery of new therapeutic approaches. Small molecule activators of mitophagy, either activating PINK1 or Parkin directly or inhibiting Parkin's counterplayer, the ubiquitin-specific protease USP30, are in preclinical development. To enable clinical success of future small molecule mitophagy enhancers, biomarkers for mitochondrial integrity and mitophagy are being developed. Only a few years after the discovery of mitophagy deficits in Parkinson's disease, research of the underlying mechanisms, drug discovery of modulators for this mechanism and identification of biomarkers provide new avenues towards the development of disease-modifying therapies.


Assuntos
/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Proteínas Quinases/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Humanos , Proteínas Mitocondriais/antagonistas & inibidores , Mutação , Doença de Parkinson/genética , Proteínas Quinases/genética , Tioléster Hidrolases/antagonistas & inibidores , Ubiquitina-Proteína Ligases/genética
9.
Cell Physiol Biochem ; 52(3): 468-485, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30873822

RESUMO

BACKGROUND/AIMS: Breast cancer is a clinically and molecularly heterogeneous disease. Patients with triple-negative breast cancer (TNBC) have poorer outcomes than those with other breast cancer subtypes due to lack of effective molecular targets for therapy. The present study aimed to the identification of estrogen receptor (ER)ß as a novel mitochondrial target in TNBC cells, together with underlying mechanisms. METHODS: Expression of ERß in clinical breast samples were examined by qRT-PCR, immunohistochemistry and immunoblotting. Subcellular distribution and binding of ERß-Grp75 was determined by confocal microscopic analysis, co-immunoprecipitation experiments, and limited-detergent extraction of subcellular organelles. The effect of mitocondrial ERß(mitoERß) overexpression on cell proliferation and cell cycle distribution were assessed CCK-8 assays and FACS. Mitochondrial ROS, membrane potential, and Ca²âº level were measured using the specific fluorescent probes Mito-Sox, TMRE, and Rhod-2AM. The tumorigenic effect of mitoERß overexpression was assessed using an anchorage-independent growth assay, sphere formation and a mouse orthotopic xenograft model. RESULTS: ERß expression was lower in tumor tissue than in adjacent normal tissue of patients with breast cancer, and low levels of mitochondrial ERß (mitoERß) also were associated with increased tumor recurrence after surgery. Overexpression of mitoERß inhibited the proliferation of TNBC cells and tumor masses in an animal model. Moreover, overexpression of mitoERß increased ATP production in TNBC cells and normal breast MCF10A cells, with the latter completely reversed by mitoERß knockdown in MCF10A cells. Grp75 was found to positively regulate ERß translocation into mitochondria via a direct interaction. Coimmunoprecipitation and subcellular fractionation experiments revealed that ERß-Grp75 complex is stable in mitochondria. CONCLUSION: These results suggest that the up-regulation of mitoERß in TNBC cells ensures proper mitochondrial transcription, activating the OXPHOS system to produce ATP. Studying the effects of mitoERß on mitochondrial activity and specific mitochondrial gene expression in breast cancer might help predict tumor recurrence, inform clinical decision-making, and identify novel drug targets in the treatment of TNBC.


Assuntos
Trifosfato de Adenosina/biossíntese , Receptor beta de Estrogênio/genética , Regulação Neoplásica da Expressão Gênica , Proteínas de Choque Térmico HSP70/genética , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Neoplasias de Mama Triplo Negativas/genética , Animais , Cálcio/metabolismo , Ciclo Celular , Linhagem Celular Tumoral , Proliferação de Células , Receptor beta de Estrogênio/antagonistas & inibidores , Receptor beta de Estrogênio/metabolismo , Feminino , Corantes Fluorescentes/química , Proteínas de Choque Térmico HSP70/antagonistas & inibidores , Proteínas de Choque Térmico HSP70/metabolismo , Humanos , Camundongos , Mitocôndrias/genética , Mitocôndrias/patologia , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/metabolismo , Estadiamento de Neoplasias , Fosforilação Oxidativa , Ligação Proteica , Transporte Proteico , RNA Interferente Pequeno/biossíntese , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Análise de Sobrevida , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/mortalidade , Neoplasias de Mama Triplo Negativas/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Am J Physiol Cell Physiol ; 316(6): C862-C875, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30865517

RESUMO

The attachment of O-linked ß-N-acetylglucosamine (O-GlcNAc) to the serine and threonine residues of proteins in distinct cellular compartments is increasingly recognized as an important mechanism regulating cellular function. Importantly, the O-GlcNAc modification of mitochondrial proteins has been identified as a potential mechanism to modulate metabolism under stress with both potentially beneficial and detrimental effects. This suggests that temporal and dose-dependent changes in O-GlcNAcylation may have different effects on mitochondrial function. In the current study, we found that acutely augmenting O-GlcNAc levels by inhibiting O-GlcNAcase with Thiamet-G for up to 6 h resulted in a time-dependent decrease in cellular bioenergetics and decreased mitochondrial complex I, II, and IV activities. Under these conditions, mitochondrial number was unchanged, whereas an increase in the protein levels of the subunits of several electron transport complex proteins was observed. However, the observed bioenergetic changes appeared not to be due to direct increased O-GlcNAc modification of complex subunit proteins. Increases in O-GlcNAc were also associated with an accumulation of mitochondrial ubiquitinated proteins; phosphatase and tensin homolog induced kinase 1 (PINK1) and p62 protein levels were also significantly increased. Interestingly, the increase in O-GlcNAc levels was associated with a decrease in the protein levels of the mitochondrial Lon protease homolog 1 (LonP1), which is known to target complex IV subunits and PINK1, in addition to other mitochondrial proteins. These data suggest that impaired bioenergetics associated with short-term increases in O-GlcNAc levels could be due to impaired, LonP1-dependent, mitochondrial complex protein turnover.


Assuntos
Proteases Dependentes de ATP/metabolismo , Acetilglucosamina/metabolismo , Regulação para Baixo/fisiologia , Metabolismo Energético/fisiologia , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo , beta-N-Acetil-Hexosaminidases/metabolismo , Proteases Dependentes de ATP/antagonistas & inibidores , Linhagem Celular , Relação Dose-Resposta a Droga , Humanos , Proteínas Mitocondriais/antagonistas & inibidores
11.
Int Immunopharmacol ; 71: 61-67, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30877875

RESUMO

Sepsis-induced hepatic dysfunction is considered as an independent risk factor of multiple organ dysfunction syndrome (MODS) and death. Mitophagy, a selective form of autophagy, plays a major role in sepsis-induced organ damage. We have demonstrated that hydrogen gas (H2), a selective antioxidant, exerts protective effects in septic mice. Here, we hypothesize that the therapeutic effects of H2 on septic animals with liver damages may be exerted through regulation of the Fun14 domain-containing protein 1 (FUDNC1)-induced mitophagy pathway. Male C57BL/6J mice were subjected to sham or cecal ligation and puncture (CLP) operation and treated with 2% H2 gas inhalation for 3 h starting at 1 h after sham or CLP surgery. To verify the role of FUNDC1, the cell-penetrating peptide P (NH2-GRKKRRQRRRPQDYESDDESYEVLDLTEY-COOH) (1 mg/kg) that functions as a FUNDC1 inhibitor was intraperitoneally injected into mice 24 h before the sham or CLP operation. To evaluate the severity of septic liver injury, the 7-day survival rate, liver histopathologic score, alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, respiration control ratio (RCR), and FUDNC1, P-18-FUDNC1, P62, LC3B-II, Tim23, and caspase-1 levels were evaluated after the sham or CLP operation. The results demonstrated that 2% H2 gas inhalation resulted in an increase in the 7-day survival rate, ALT and AST levels, RCR, and P62 and LC3B-II expression but decreased the histological score and FUDNC1, P-18-FUDNC1, Tim23, and caspase-1 levels after sepsis. However, no significant differences were reported between the CLP + peptide P and CLP + H2 + peptide P groups. These observations indicate that 2% H2 gas inhalation for 3 h may serve as an effective therapeutic strategy for sepsis-induced liver injury through the regulation of FUNDC1-dependent mitophagy.


Assuntos
Antioxidantes/uso terapêutico , Hidrogênio/uso terapêutico , Hepatopatias/terapia , Fígado/patologia , Proteínas de Membrana/metabolismo , Proteínas Mitocondriais/metabolismo , Sepse/terapia , Administração por Inalação , Animais , Ceco/cirurgia , Peptídeos Penetradores de Células/administração & dosagem , Peptídeos Penetradores de Células/farmacologia , Modelos Animais de Doenças , Humanos , Fígado/metabolismo , Masculino , Proteínas de Membrana/antagonistas & inibidores , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Mitocondriais/antagonistas & inibidores , Transaminases/sangue
12.
J Biol Chem ; 294(16): 6550-6561, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-30824536

RESUMO

Site-specific suppressors of superoxide production (named S1QELs) in the quinone-reaction site in mitochondrial respiratory complex I during reverse electron transfer have been previously reported; however, their mechanism of action remains elusive. Using bovine heart submitochondrial particles, we herein investigated the effects of S1QELs on complex I functions. We found that the inhibitory effects of S1QELs on complex I are distinctly different from those of other known quinone-site inhibitors. For example, the inhibitory potencies of S1QELs significantly varied depending on the direction of electron transfer (forward or reverse). S1QELs marginally suppressed the specific chemical modification of Asp160 in the 49-kDa subunit, located deep in the quinone-binding pocket, by the tosyl chemistry reagent AL1. S1QELs also failed to suppress the binding of a photoreactive quinazoline-type inhibitor ([125I]AzQ) to the 49-kDa subunit. Moreover, a photoaffinity labeling experiment with photoreactive S1QEL derivatives indicated that they bind to a segment in the ND1 subunit that is not considered to make up the binding pocket for quinone or inhibitors. These results indicate that unlike known quinone-site inhibitors, S1QELs do not occupy the quinone- or inhibitor-binding pocket; rather, they may indirectly modulate the quinone-redox reactions by inducing structural changes of the pocket through binding to ND1. We conclude that this indirect effect may be a prerequisite for S1QELs' direction-dependent modulation of electron transfer. This, in turn, may be responsible for the suppression of superoxide production during reverse electron transfer without significantly interfering with forward electron transfer.


Assuntos
Complexo I de Transporte de Elétrons , Inibidores Enzimáticos/farmacologia , Mitocôndrias Cardíacas/metabolismo , Proteínas Mitocondriais , Superóxidos/metabolismo , Animais , Domínio Catalítico , Bovinos , Transporte de Elétrons/efeitos dos fármacos , Complexo I de Transporte de Elétrons/antagonistas & inibidores , Complexo I de Transporte de Elétrons/metabolismo , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/metabolismo
13.
Cancer Lett ; 452: 226-236, 2019 06 28.
Artigo em Inglês | MEDLINE | ID: mdl-30905812

RESUMO

UHRF1 (ubiquitin like with plant homeodomain and ring finger domains 1) is an epigenetic modifier that is overexpressed in some cancers, including pancreatic cancer, and mediates silencing of tumor suppressor genes. However, the role of UHRF1 in regulating pancreatic cancer metabolism and metastasis is not clear. In the present study, we demonstrated that silencing UHRF1 significantly inhibited aerobic glycolysis in pancreatic cancer cells. Furthermore, we demonstrated that UHRF1 knockdown decreased hypoxia inducible factor (HIF)1α levels and HIF1α targeted glycolytic genes. The Cancer Genome Atlas dataset analysis supported this observation. The Sirtuin (SIRT) family members regulate aerobic glycolysis in many cancers. We analyzed the correlation between UHRF1 and SIRT3-5 expression and found a significant negative correlation between UHRF1 and SIRT4. Further transcriptional and functional analysis demonstrates that SIRT4 is a downstream target of UHRF1 and negatively regulated aerobic glycolysis, cell proliferation and tumor growth. Our study identified a novel UHRF1/SIRT4 axis in regulation of pancreatic cancer cell proliferation, metabolism, and metastasis.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Glicólise/fisiologia , Proteínas Mitocondriais/antagonistas & inibidores , Neoplasias Pancreáticas/patologia , Sirtuínas/antagonistas & inibidores , Ubiquitina-Proteína Ligases/metabolismo , Apoptose/fisiologia , Proteínas Estimuladoras de Ligação a CCAAT/genética , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Glicólise/genética , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Metástase Neoplásica/patologia , Consumo de Oxigênio/fisiologia , Ubiquitina-Proteína Ligases/genética
14.
Oxid Med Cell Longev ; 2019: 9817576, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30805086

RESUMO

The mitochondrial protein mitoNEET is a type of iron-sulfur protein localized to the outer membrane of mitochondria and is involved in a variety of human pathologies including cystic fibrosis, diabetes, muscle atrophy, and neurodegeneration. In the current study, we found that isoliquiritigenin (ISL), one of the components of the root of Glycyrrhiza glabra L., could decrease the expression of mitoNEET in A375 melanoma cells. We also demonstrated that mitoNEET could regulate the content of reactive oxygen species (ROS), by showing that the ISL-mediated increase in the cellular ROS content could be mitigated by the mitoNEET overexpression. We also confirmed the important role of ROS in ISL-treated A375 cells. The increased apoptosis rate and the decreased mitochondrial membrane potential were mitigated by the overexpression of mitoNEET in A375 cells. These findings indicated that ISL could decrease the expression of mitoNEET, which regulated ROS content and subsequently induced mitochondrial dysfunction and apoptosis in A375 cells. Our findings also highlight mitoNEET as a promising mitochondrial target for cancer therapy.


Assuntos
Apoptose/efeitos dos fármacos , Chalconas/farmacologia , Melanoma/metabolismo , Melanoma/patologia , Mitocôndrias/patologia , Proteínas Mitocondriais/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/metabolismo
15.
Biochim Biophys Acta Mol Basis Dis ; 1865(6): 1460-1476, 2019 06 01.
Artigo em Inglês | MEDLINE | ID: mdl-30802640

RESUMO

An increased level of proinflammatory cytokines, including TNF-α in tumor microenvironment regulates the bioenergetic capacity, immune evasion and survival of cancer cells. Emerging evidences suggest that mitochondrial immune signaling proteins modulates mitochondrial bioenergetic capacity, in addition to the regulation of innate immune response. The optimal oxidative phosphorylation (OxPhos) capacity is required for the maintenance of functional lysosomes and autophagy flux. NLRX1, a mitochondrial NOD family receptor protein, regulates mitochondrial function during apoptosis and tissue injury. However, its role in regulation of mitochondrial and lysosomal function to modulate autophagy flux during inflammatory conditions is not understood. In the current study, we investigated the role of NLRX1 in modulating TNF-α induced autophagy flux and mitochondrial turnover and its implication in regulating the invasive and metastatic capability of breast cancer cells. Expression analyses of clinical breast cancer samples and meta-analysis of multiple public databases revealed that NLRX1 expression is significantly increased in basal-like and metastatic breast carcinoma as compared to non-basal-like and primary breast cancer. Depletion of NLRX1 expression in triple-negative breast cancer cells, altered the organization and activity of OxPhos complexes in presence of TNF-α. NLRX1 depletion further impaired lysosomal function and hence the turnover of damaged mitochondria through mitophagy in presence of TNF-α. Importantly, loss of NLRX1 decreased OxPhos-dependent cell proliferation and migration ability of triple-negative breast cancer cells in presence of TNF-α. These evidences suggest an essential role of NLRX1 in maintaining the crosstalk of mitochondrial metabolism and lysosomal function to regulate invasion and metastasis capability of breast cancer cells.


Assuntos
Neoplasias da Mama/genética , Regulação Neoplásica da Expressão Gênica , Lisossomos/metabolismo , Mitocôndrias/metabolismo , Proteínas Mitocondriais/genética , Fator de Necrose Tumoral alfa/genética , Autofagia/efeitos dos fármacos , Autofagia/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Feminino , Células HEK293 , Humanos , Metástase Linfática , Lisossomos/efeitos dos fármacos , Células MCF-7 , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/patologia , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/metabolismo , /genética , Invasividade Neoplásica , Fosforilação Oxidativa/efeitos dos fármacos , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Microambiente Tumoral/genética , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/farmacologia
16.
EBioMedicine ; 41: 384-394, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30803933

RESUMO

BACKGROUND: FUN14 domain-containing 1 (FUNDC1), as a novel member of mitochondria-associated endoplasmic reticulum (ER) membranes associates with mitochondrial division and mitophagy. However, the expression profile and functional roles of FUNDC1 remain largely unclear in human cancer biology, including breast cancer (BC). METHODS: Immunohistochemistry and western blot analysis were used to determine the expression of FUNDC1 and BMI1 polycomb ring finger oncogene (BMI1). CCK8, cell counting and transwell assays were used to analyze cell proliferation, migration and invasion, respectively. Luciferase reporter and chromatin immunoprecipitation (ChIP) assays were used to detect the transcriptional regulation of Nuclear factor of activated T-cells, cytoplasmic 1 (NFATC1). The prognostic merit of NFATC1 expression was assessed by Kaplan-Meier assay. FINDINGS: Immunohistochemistry revealed strong immunostaining for FUNDC1 in cytoplasmic and nuclear membrane distribution in BC tissues as compared with normal breast epithelium. Kaplan-Meier survival analysis showed worse outcome for BC patients with high FUNDC1 expression. In vitro assay of gain- and loss-of-function of FUNDC1 suggested that FUNDC1 could stimulate BC cell proliferation, migration and invasion. Furthermore, elevated FUNDC1 level promoted Ca2+ cytosol influx from ER and extracellular, as well as NFATC1 nuclear translocation and activity. Nuclear NFATC1 bound to the BMI1 gene promoter and transcriptionally upregulated its expression. Notably, BMI1 overexpression could rescue the loss of function of FUNDC1. Co-expression of FUNDC1 and BMI1 in BC patients predicted worse prognosis than without either expression. INTERPRETATION: FUNDC1 might promote BC progression by activating the Ca2+-NFATC1-BMI1 axis. This pathway may be promising for developing multiple targets for BC therapy.


Assuntos
Neoplasias da Mama/patologia , Cálcio/metabolismo , Proteínas de Membrana/metabolismo , Proteínas Mitocondriais/metabolismo , Fatores de Transcrição NFATC/metabolismo , Complexo Repressor Polycomb 1/metabolismo , Neoplasias da Mama/metabolismo , Neoplasias da Mama/mortalidade , Canais de Cálcio/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Humanos , Estimativa de Kaplan-Meier , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Pessoa de Meia-Idade , Proteínas Mitocondriais/antagonistas & inibidores , Proteínas Mitocondriais/genética , Fatores de Transcrição NFATC/antagonistas & inibidores , Fatores de Transcrição NFATC/genética , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Molécula 1 de Interação Estromal/antagonistas & inibidores , Molécula 1 de Interação Estromal/genética , Molécula 1 de Interação Estromal/metabolismo
17.
Cardiovasc Drugs Ther ; 33(1): 13-23, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30637549

RESUMO

PURPOSE: Necroptosis is an important form of cell death following myocardial ischemia/reperfusion (I/R) and phosphoglycerate mutase 5 (PGAM5) functions as the convergent point for multiple necrosis pathways. This study aims to investigate whether inhibition of PGAM5 could reduce I/R-induced myocardial necroptosis and the underlying mechanisms. METHODS: The SD rat hearts (or H9c2 cells) were subjected to 1-h ischemia (or 10-h hypoxia) plus 3-h reperfusion (or 4-h reoxygenation) to establish the I/R (or H/R) injury model. The myocardial injury was assessed by the methods of biochemistry, H&E (hematoxylin and eosin), and PI/DAPI (propidium iodide/4',6-diamidino-2-phenylindole) staining, respectively. Drug interventions or gene knockdown was used to verify the role of PGAM5 in I/R (or H/R)-induced myocardial necroptosis and possible mechanisms. RESULTS: The I/R-treated heart showed the injuries (increase in infarct size and creatine kinase release), upregulation of PGAM5, dynamin-related protein 1 (Drp1), p-Drp1-S616, and necroptosis-relevant proteins (RIPK1/RIPK3, receptor-interacting protein kinase 1/3; MLKL, mixed lineage kinase domain-like); these phenomena were attenuated by inhibition of PGAM5 or RIPK1. In H9c2 cells, H/R treatment elevated the levels of PGAM5, RIPK1, RIPK3, MLKL, Drp1, and p-Drp1-S616 and induced mitochondrial dysfunctions (elevation in mitochondrial membrane potential and ROS level) and cellular necrosis (increase in LDH release and the ratio of PI+/DAPI+ cells); these effects were blocked by inhibition or knockdown of PGAM5. CONCLUSIONS: Inhibition of PGAM5 can reduce necroptosis in I/R-treated rat hearts through suppression of Drp1; there is a positive feedback between RIPK1 and PGAM5, and PGAM5 might serve as a novel therapeutic target for prevention of myocardial I/R injury.


Assuntos
DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Inibidores Enzimáticos/farmacologia , Glicolatos/farmacologia , Proteínas Mitocondriais/antagonistas & inibidores , Infarto do Miocárdio/prevenção & controle , Traumatismo por Reperfusão Miocárdica/prevenção & controle , Miócitos Cardíacos/efeitos dos fármacos , Fosfoglicerato Mutase/antagonistas & inibidores , Fosfoproteínas Fosfatases/antagonistas & inibidores , Animais , Morte Celular/efeitos dos fármacos , Linhagem Celular , Modelos Animais de Doenças , Regulação para Baixo , Masculino , Proteínas Mitocondriais/genética , Proteínas Mitocondriais/metabolismo , Infarto do Miocárdio/enzimologia , Infarto do Miocárdio/patologia , Traumatismo por Reperfusão Miocárdica/enzimologia , Traumatismo por Reperfusão Miocárdica/patologia , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/patologia , Fosfoglicerato Mutase/genética , Fosfoglicerato Mutase/metabolismo , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/metabolismo , Proteínas Serina-Treonina Quinases/metabolismo , Ratos Sprague-Dawley , Transdução de Sinais/efeitos dos fármacos
18.
Nat Commun ; 10(1): 329, 2019 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-30659190

RESUMO

We previously demonstrated that beta II protein kinase C (ßIIPKC) activity is elevated in failing hearts and contributes to this pathology. Here we report that ßIIPKC accumulates on the mitochondrial outer membrane and phosphorylates mitofusin 1 (Mfn1) at serine 86. Mfn1 phosphorylation results in partial loss of its GTPase activity and in a buildup of fragmented and dysfunctional mitochondria in heart failure. ßIIPKC siRNA or a ßIIPKC inhibitor mitigates mitochondrial fragmentation and cell death. We confirm that Mfn1-ßIIPKC interaction alone is critical in inhibiting mitochondrial function and cardiac myocyte viability using SAMßA, a rationally-designed peptide that selectively antagonizes Mfn1-ßIIPKC association. SAMßA treatment protects cultured neonatal and adult cardiac myocytes, but not Mfn1 knockout cells, from stress-induced death. Importantly, SAMßA treatment re-establishes mitochondrial morphology and function and improves cardiac contractility in rats with heart failure, suggesting that SAMßA may be a potential treatment for patients with heart failure.


Assuntos
Insuficiência Cardíaca/tratamento farmacológico , Proteínas de Membrana/antagonistas & inibidores , Proteínas Mitocondriais/antagonistas & inibidores , Peptídeos/farmacologia , Proteína Quinase C beta/antagonistas & inibidores , Animais , GTP Fosfo-Hidrolases/metabolismo , Técnicas de Inativação de Genes , Insuficiência Cardíaca/metabolismo , Masculino , Membranas Mitocondriais/metabolismo , Contração Miocárdica , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Miócitos Cardíacos/efeitos dos fármacos , Fosforilação , RNA Interferente Pequeno , Ratos Wistar
19.
Plant Physiol Biochem ; 136: 92-97, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30660100

RESUMO

Aluminum (Al) toxicity has been recognized to be a main limiting factor of crop productivity in acid soil. Al interacts with cell walls disrupting the functions of the plasma membrane and is associated with oxidative damage and mitochondrial dysfunction. Jatropha curcas L. (J. curcas) is a drought resistant plant, widely distributed around the world, with great economic and medicinal importance. Here we investigated the effects of Al on J. curcas mitochondrial function and cell viability, analyzing mitochondrial respiration, phenolic compounds, reducing sugars and cell viability in cultured J. curcas cells. The results showed that at 70 µM, Al limited mitochondrial respiration by inhibiting the alternative oxidase (AOX) pathway in the respiratory chain. An increased concentration of reducing sugars and reduced concentration of intracellular phenolic compounds was observed during respiratory inhibition. After inhibition, a time-dependent upregulation of AOX mRNA was observed followed by restoration of respiratory activity and reducing sugar concentrations. Cultured J. curcas cells were very resistant to Al-induced cell death. In addition, at 70 µM, Al also appeared as an inhibitor of cell wall invertase. In conclusion, Al tolerance in cultured J. curcas cells involves a inhibition of mitochondrial AOX pathway, which seems to start an oxidative burst to induce AOX upregulation, which in turn restores consumption of O2 and substrates. These data provide new insight into the signaling cascades that modulate the Al tolerance mechanism.


Assuntos
Alumínio/farmacologia , Jatropha/efeitos dos fármacos , Proteínas Mitocondriais/metabolismo , Oxirredutases/metabolismo , Proteínas de Plantas/metabolismo , Técnicas de Cultura de Células , Jatropha/enzimologia , Jatropha/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteínas Mitocondriais/antagonistas & inibidores , Oxirredução/efeitos dos fármacos , Oxirredutases/antagonistas & inibidores , Consumo de Oxigênio/efeitos dos fármacos , Proteínas de Plantas/antagonistas & inibidores
20.
Pest Manag Sci ; 75(5): 1295-1303, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30350447

RESUMO

BACKGROUND: Moniliophthora perniciosa (Stahel) Aime & Phillips-Mora is the causal agent of witches' broom disease (WBD) of cocoa (Theobroma cacao L.) and a threat to the chocolate industry. The membrane-bound enzyme alternative oxidase (AOX) is critical for M. perniciosa virulence and resistance to fungicides, which has also been observed in other phytopathogens. Notably AOX is an escape mechanism from strobilurins and other respiration inhibitors, making AOX a promising target for controlling WBD and other fungal diseases. RESULTS: We present the first study aimed at developing novel fungal AOX inhibitors. N-Phenylbenzamide (NPD) derivatives were screened in the model yeast Pichia pastoris through oxygen consumption and growth measurements. The most promising AOX inhibitor (NPD 7j-41) was further characterized and displayed better activity than the classical AOX inhibitor SHAM in vitro against filamentous fugal phytopathogens, such as M. perniciosa, Sclerotinia sclerotiorum and Venturia pirina. We demonstrate that 7j-41 inhibits M. perniciosa spore germination and prevents WBD symptom appearance in infected plants. Finally, a structural model of P. pastoris AOX was created and used in ligand structure-activity relationships analyses. CONCLUSION: We present novel fungal AOX inhibitors with antifungal activity against relevant phytopathogens. We envisage the development of novel antifungal agents to secure food production. © 2018 Society of Chemical Industry.


Assuntos
Agaricales/efeitos dos fármacos , Agaricales/fisiologia , Benzamidas/síntese química , Benzamidas/farmacologia , Cacau/microbiologia , Proteínas Mitocondriais/antagonistas & inibidores , Oxirredutases/antagonistas & inibidores , Doenças das Plantas/microbiologia , Proteínas de Plantas/antagonistas & inibidores , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Benzamidas/química , Técnicas de Química Sintética , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Relação Estrutura-Atividade
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA