RESUMO
In eukaryotic cells, molecular fate and cellular responses are shaped by multicomponent enzyme systems which reversibly attach ubiquitin and ubiquitin-like modifiers to target proteins. The extent of the ubiquitin proteasome system in Leishmania mexicana and its importance for parasite survival has recently been established through deletion mutagenesis and life-cycle phenotyping studies. The ubiquitin conjugating E2 enzyme UBC2, and the E2 enzyme variant UEV1, with which it forms a stable complex in vitro, were shown to be essential for the differentiation of promastigote parasites to the infectious amastigote form. To investigate further, we used immunoprecipitation of Myc-UBC2 or Myc-UEV1 to identify interacting proteins in L. mexicana promastigotes. The interactome of UBC2 comprises multiple ubiquitin-proteasome components including UEV1 and four RING E3 ligases, as well as potential substrates predicted to have roles in carbohydrate metabolism and intracellular trafficking. The smaller UEV1 interactome comprises six proteins, including UBC2 and shared components of the UBC2 interactome consistent with the presence of intracellular UBC2-UEV1 complexes. Recombinant RING1, RING2 and RING4 E3 ligases were shown to support ubiquitin transfer reactions involving the E1, UBA1a, and UBC2 to available substrate proteins or to unanchored ubiquitin chains. These studies define additional components of a UBC2-dependent ubiquitination pathway shown previously to be essential for promastigote to amastigote differentiation.
Assuntos
Leishmania mexicana , Proteínas de Protozoários , Enzimas de Conjugação de Ubiquitina , Ubiquitina-Proteína Ligases , Enzimas de Conjugação de Ubiquitina/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Proteínas de Protozoários/metabolismo , Proteínas de Protozoários/genética , Leishmania mexicana/genética , Leishmania mexicana/enzimologia , Leishmania mexicana/metabolismo , Ligação Proteica , Mapeamento de Interação de Proteínas , ImunoprecipitaçãoRESUMO
SUMMARY: Gastrin plays a vital role in the development and progression of gastric cancer (GC). Its expression is up-regulated in GC tissues and several GC cell lines. Yet, the underlying mechanism remains to be investigated. Here, we aim to investigate the role and mechanism of gastrin in GC proliferation. Gastrin-overexpressing GC cell model was constructed using SGC7901 cells. Then the differentially expressed proteins were identified by iTRAQ analysis. Next, we use flow cytometry and immunofluorescence to study the effect of gastrin on the mitochondrial potential and mitochondria-derived ROS production. Finally, we studied the underlying mechanism of gastrin regulating mitochondrial function using Co-IP, mass spectrometry and immunofluorescence. Overexpression of gastrin promoted GC cell proliferation in vitro and in vivo. A total of 173 proteins were expressed differently between the controls and gastrin- overexpression cells and most of these proteins were involved in tumorigenesis and cell proliferation. Among them, Cox17, Cox5B and ATP5J that were all localized to the mitochondrial respiratory chain were down-regulated in gastrin-overexpression cells. Furthermore, gastrin overexpression led to mitochondrial potential decrease and mitochondria-derived ROS increase. Additionally, gastrin-induced ROS generation resulted in the inhibition of cell apoptosis via activating NF-kB, inhibiting Bax expression and promoting Bcl-2 expression. Finally, we found gastrin interacted with mitochondrial membrane protein Annexin A2 using Co-IP and mass spectrometry. Overexpr ession of gastrin inhibits GC cell apoptosis by inducing mitochondrial dysfunction through interacting with mitochondrial protein Annexin A2, then up-regulating ROS production to activate NF-kB and further leading to Bax/Bcl-2 ratio decrease.
La gastrina juega un papel vital en el desarrollo y progresión del cáncer gástrico (CG). Su expresión está regulada al alza en tejidos de CG y en varias líneas celulares de CG. Sin embargo, el mecanismo subyacente aun no se ha investigado. El objetivo de este estudio fue investigar el papel y el mecanismo de la gastrina en la proliferación de CG. El modelo de células CG que sobre expresan gastrina se construyó usando células SGC7901. Luego, las proteínas expresadas diferencialmente se identificaron mediante análisis iTRAQ. A continuación, utilizamos la citometría de flujo y la inmunofluorescencia para estudiar el efecto de la gastrina en el potencial mitocondrial y la producción de ROS derivada de las mitocondrias. Finalmente, estudiamos el mecanismo subyacente de la gastrina que regula la función mitocondrial utilizando Co-IP, espectrometría de masas e inmunofluorescencia. La sobreexpresión de gastrina promovió la proliferación de células CG in vitro e in vivo. Un total de 173 proteínas se expresaron de manera diferente entre los controles y las células con sobreexpresión de gastrina y la mayoría de estas proteínas estaban implicadas en la tumorigenesis y la proliferación celular. Entre estas, Cox17, Cox5B y ATP5J, todas localizadas en la cadena respiratoria mitocondrial, estaban reguladas a la baja en las células con sobreexpresión de gastrina. Además, la sobreexpresión de gastrina provocó una disminución del potencial mitocondrial y un aumento de las ROS derivadas de las mitocondrias. Por otra parte, la generación de ROS inducida por gastrina resultó en la inhibición de la apoptosis celular mediante la activación de NF-kB, inhibiendo la expresión de Bax y promoviendo la expresión de Bcl-2. Finalmente, encontramos que la gastrina interactuaba con la proteína de membrana mitocondrial Anexina A2 usando Co-IP y espectrometría de masas. La sobreexpresión de gastrina inhibe la apoptosis de las células CG al inducir la disfunción mitocondrial a través de la interacción con la proteína mitocondrial Anexina A2, luego regula el aumento de la producción de ROS para activar NF-kB y conduce aún más a la disminución de la relación Bax/Bcl-2.
Assuntos
Animais , Camundongos , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patologia , Gastrinas/metabolismo , Anexina A2/metabolismo , Mitocôndrias/patologia , Espectrometria de Massas , NF-kappa B , Imunofluorescência , Espécies Reativas de Oxigênio , Apoptose , Linhagem Celular Tumoral , Imunoprecipitação , Proliferação de Células , Carcinogênese , Citometria de FluxoRESUMO
Background: Isoliquiritigenin (ISL) presents antitumor effects against melanoma cells. It is known that various circular RNAs (circRNAs) are involved in the development of melanoma. Therefore, the present study aims to investigate the molecular mechanisms of ISL and circ_0002860. Methods: Circ_0002860, microRNA-431-5p (miR-431-5p) and member RAS oncogene family (RAB9A) were detected through reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay. Cell viability was examined via cell counting kit-8 assay. The proliferation ability was assessed using colony formation assay. Cell apoptosis and cell cycle were determined by flow cytometry. Transwell assay was used for detection of migration and invasion. Western blot was conducted for protein analysis. Target binding was confirmed via dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. In vivo research was performed through xenograft tumor assay. Results: Circ_0002860 was downregulated by ISL in melanoma cells. ISL-induced inhibitory effects on cell proliferation, cell cycle progression, migration and invasion were alleviated by circ_0002860 overexpression. MiR-431-5p was a target of circ_0002860. Circ_0002860 eliminated the ISL-induced tumor inhibition via sponging miR-431-5p in melanoma cells. Circ_0002860 elevated the RAB9A level by targeting miR-431-5p. The function of ISL was related to miR-431-5p/RAB9A axis in melanoma progression. Tumor growth was reduced by ISL in vivo through downregulating circ_0002860 to regulate miR-431-5p and RAB9A levels. Conclusion: The current data indicates that ISL suppressed cell malignant progression of melanoma via targeting the circ_0002860/miR-431-5p/RAB9A pathway.(AU)
Assuntos
Fenóis/análise , Melanoma/tratamento farmacológico , Antineoplásicos/efeitos adversos , ImunoprecipitaçãoRESUMO
Anti-fibrillarin autoantibodies are useful for the diagnosis and prognosis of systemic sclerosis (SSc). Anti-fibrillarin produces a clumpy nucleolar pattern in indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA). Here we develop and validate a reliable cell-based anti-fibrillarin assay (Fibrillarin/CBA) for use in clinical diagnostic laboratories. A TransMembrane Signal was fused to the human fibrillarin gene (TMS-fibrillarin). HEp-2 cells overexpressing transgenic TMS-fibrillarin at the cytoplasmic membrane were used as IFA substrate in the Fibrillarin/CBA. Sixty-two serum samples with nucleolar pattern in the HEp-2 IFA (41 clumpy; 21 homogeneous/punctate) were tested for anti-fibrillarin using Fibrillarin/CBA, immunoprecipitation (IP), line-blot and ELISA. In addition, samples from 106 SSc-patients were evaluated with Fibrillarin/CBA and the results were correlated with disease phenotypes. Thirty-eight of 41 samples with the clumpy nucleolar pattern (92.7%) were positive in the Fibrillarin/CBA, while all 21 samples with other nucleolar patterns were negative. Fibrillarin/CBA results agreed 100% with IP results. Among the 38 Fibrillarin/CBA-positive samples, only 15 (39.5%) and 11 (29%) were positive for anti-fibrillarin in line-blot and ELISA, respectively. Higher frequency of diffuse cutaneous SSc (dcSSc) phenotype (72.7% vs 36.8%; p=0.022), cardiac involvement (36.4% vs 6.5%; p=0.001) and scleroderma renal crisis (18.2% vs 3.3% p = 0.028) was observed in SSc patients with positive compared to negative Fibrillarin/CBA result. Performance of Fibrillarin/CBA in the detection of anti-fibrillarin autoantibodies was comparable to the gold standard IP. Positive Fibrillarin/CBA results correlated with disease phenotypes known to be associated with anti-fibrillarin autoantibodies, underscoring the clinical validation of this novel assay.
Assuntos
Autoanticorpos , Escleroderma Sistêmico , Ensaio de Imunoadsorção Enzimática , Técnica Indireta de Fluorescência para Anticorpo , Humanos , Imunoprecipitação , Escleroderma Sistêmico/diagnósticoRESUMO
Coimmunoprecipitation is a powerful and commonly used method to identify protein-protein interactions in a physiological context. Here, we report a coimmunoprecipitation protocol that was adapted and optimized for the haloarchaeon Haloferax volcanii to identify interacting partners to the LonB protease. This protocol includes the in vivo cross-linking of H. volcanii proteins using two different crosslinker agents, dithiobis(succinimidyl propionate) and formaldehyde, followed by immunoprecipitation with anti-LonB antibody conjugated to Protein A - Sepharose beads. Tryptic on-bead protein digestion was performed combined with Mass Spectrometry analysis of peptides for the identification and quantification of LonB ligands.
Assuntos
Haloferax volcanii , Formaldeído , Imunoprecipitação , Peptídeo Hidrolases/metabolismo , Peptídeos/análise , Propionatos , Proteínas , SefaroseRESUMO
BACKGROUND: Hepatocellular carcinoma (HCC) is a primary liver cancer with a high mortality rate. It has been reported that circular RNA hsa_circ_0091579 (circ_0091579) is involved in HCC progression. Nevertheless, the molecular mechanism by which circ_0091579 modulates HCC advancement is indistinct. METHODS: The expression of circ_0091579, microRNA (miR)-624, and H3 histone family member 3B (H3F3B) mRNA was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The extracellular acidification rate (ECAR) and oxygen consumption rate (OCR) of HCC cells were analyzed using an extracellular flux analyzer. Adenosine triphosphate (ATP) level was evaluated using a commercial kit. Cell migration, invasion, and apoptosis were assessed by wound-healing, transwell, or flow cytometry assay. The relationship between miR-624 and circ_0091579 or H3F3B was verified using luciferase reporter assay and/or RNA immunoprecipitation (RIP) assay. H3F3B protein level was detected by western blotting. RESULTS: Circ_0091579 was upregulated in HCC tissues and cells. Circ_0091579 inhibition decreased xenograft tumor growth in vivo and repressed Warburg effect, migration, invasion, and induced apoptosis of HCC cells in vitro. MiR-624 was downregulated, while H3F3B was upregulated in HCC tissues and cells. Circ_0091579 acted as a miR-624 sponge and regulated H3F3B expression by adsorbing miR-624. MiR-624 inhibitor reversed circ_0091579 downregulation-mediated effects on the Warburg effect and malignant behaviors of HCC cells. H3F3B overexpression reversed the repressive impact of miR-624 mimic on the Warburg effect and malignancy of HCC cells. CONCLUSIONS: Circ_0091579 accelerated Warburg effect and tumor growth via upregulating H3F3B via adsorbing miR-624 in HCC, providing evidence to support the involvement of circ_0091579 in the progression of HCC.
Assuntos
Carcinoma Hepatocelular/metabolismo , Histonas/metabolismo , Neoplasias Hepáticas/metabolismo , MicroRNAs/metabolismo , RNA Circular/metabolismo , RNA Mensageiro/metabolismo , Efeito Warburg em Oncologia , Trifosfato de Adenosina/análise , Trifosfato de Adenosina/metabolismo , Animais , Apoptose , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Movimento Celular , Progressão da Doença , Regulação para Baixo , Humanos , Imunoprecipitação/métodos , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Camundongos , Camundongos Nus , MicroRNAs/antagonistas & inibidores , Invasividade Neoplásica , Transplante de Neoplasias , Consumo de Oxigênio , RNA Circular/antagonistas & inibidores , Regulação para CimaRESUMO
OBJECTIVES: The promoting roles of cyclin dependent kinase 1 (CDK1) have been revealed in various tumors, however, its effects in the progression of cancer stem cells are still confusing. This work aims to explore the roles of CDK1 in regulating the stemness of lung cancer cells. METHODS: Online dataset analysis was performed to evaluate the correlation between CDK1 exression and the survival of lung cancer patients. RT-qPCR, western blot, cell viability, sphere-formation analysis and ALDH activity detection were used to investigate the roles of CDK1 on lung cancer cell stemness, viability and chemotherapeutic sensitivity. Immunocoprecipitation (Co-IP) analysis and rescuing experiments were performed to reveal the underlying mechanisms contributing to CDK1-mediated effects on lung cancer cell stemness. RESULTS: CDK1 mRNA expression was negatively correlated with the overall survival of lung cancer patients and remarkably increased in tumor spheres formed by lung cancer cells compared to the parental cells. Additionally, CDK1 positively regulated the stemness of lung cancer cells. Mechanistically, CDK1 could interact with Sox2 protein, but not other stemness markers (Oct4, Nanog and CD133). Furthermore, CDK1 increased the phosphorylation, cytoplasm-nuclear translocation and transcriptional activity of Sox2 protein in lung cancer cells. Moreover, CDK1 positively regulated the stemness of lung cancer cells in a Sox2-dependent manner. Finally, we revealed that inhibition of CDK1 enhanced the chemotherapeutic sensitivity, which was also rescued by Sox2 overexpression. CONCLUSIONS: This work reveals a novel CDK1/Sox2 axis responsible for maintaining the stemness of lung cancer cells.
Assuntos
Proteína Quinase CDC2/metabolismo , Neoplasias Pulmonares/patologia , Células-Tronco Neoplásicas/patologia , Fatores de Transcrição SOXB1/metabolismo , Células A549 , Antígeno AC133/metabolismo , Adenocarcinoma/tratamento farmacológico , Adenocarcinoma/metabolismo , Adenocarcinoma/mortalidade , Adenocarcinoma/patologia , Aldeído Desidrogenase/metabolismo , Proteína Quinase CDC2/antagonistas & inibidores , Proteína Quinase CDC2/genética , Carcinoma de Células Escamosas/tratamento farmacológico , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/mortalidade , Carcinoma de Células Escamosas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular , Progressão da Doença , Humanos , Imunoprecipitação/métodos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Neoplasias Pulmonares/mortalidade , Proteína Homeobox Nanog/metabolismo , Proteínas de Neoplasias/metabolismo , Células-Tronco Neoplásicas/efeitos dos fármacos , Fator 3 de Transcrição de Octâmero/metabolismo , Fosforilação , RNA Mensageiro/metabolismo , Esferoides Celulares/patologiaRESUMO
Posttranslational modifications (PTMs) such as phosphorylation, acetylation, and glycosylation are an essential regulatory mechanism of protein function and interaction, and they are associated with a wide range of biological processes. Since most PTMs alter the molecular mass of a protein, mass spectrometry (MS) is the ideal analytical tool for studying various PTMs. However, PTMs are often present in substoichiometric levels, and therefore their unmodified counterpart often suppresses their signal in MS. Consequently, PTM analysis by MS is a challenging task, requiring highly specialized and sensitive PTM-specific enrichment methods. Currently, several methods have been implemented for PTM enrichment, and each of them has its drawbacks and advantages as they differ in selectivity and specificity toward specific protein modifications. Unfortunately, for the vast majority of more than 400 known modifications, we have no or poor tools for selective enrichment.Here, we describe a comprehensive workflow to simultaneously study phosphorylation, acetylation, and N-linked sialylated glycosylation from the same biological sample. The protocol involves an initial titanium dioxide (TiO2) step to enrich for phosphopeptides and sialylated N-linked glycopeptides followed by glycan release and post-fractionation using sequential elution from immobilized metal affinity chromatography (SIMAC) to separate mono-phosphorylated and deglycosylated peptides from multi-phosphorylated ones. The IMAC flow-through and acidic elution are subsequently subjected to a next round of TiO2 enrichment for further separation of mono-phosphopeptides from deglycosylated peptides. Furthermore, the lysine-acetylated peptides present in the first TiO2 flow-through fraction are enriched by immunoprecipitation (IP) after peptide cleanup. Finally, the samples are fractionated by high pH reversed phase chromatography (HpH) or hydrophilic interaction liquid chromatography (HILIC ) to reduce sample complexity and increase the coverage in the subsequent LC-MS /MS analysis. This allows the analysis of multiple types of modifications from the same highly complex biological sample without decreasing the quality of each individual PTM study.
Assuntos
Processamento de Proteína Pós-Traducional , Proteínas/análise , Proteômica , Acetilação , Cromatografia de Afinidade , Cromatografia de Fase Reversa , Glicosilação , Imunoprecipitação , Fosforilação , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Titânio/química , Fluxo de TrabalhoRESUMO
Giardia intestinalis is a human parasite that causes a diarrheal disease in developing countries. G. intestinalis has a cytoskeleton (CSK) composed of microtubules and microfilaments, and the Giardia genome does not code for the canonical CSK-binding proteins described in other eukaryotic cells. To identify candidate actin and tubulin cross-linking proteins, we performed a BLAST analysis of the Giardia genome using a spectraplakins consensus sequence as a query. Based on the highest BLAST score, we selected a 259-kDa sequence designated as a cytoskeleton linker protein (CLP259). The sequence was cloned in three fragments and characterized by immunoprecipitation, confocal microscopy, and mass spectrometry (MS). CLP259 was located in the cytoplasm in the form of clusters of thick rods and colocalized with actin at numerous sites and with tubulin in the median body. Immunoprecipitation followed by mass spectrometry revealed that CLP259 interacts with structural proteins such as giardins, SALP-1, axonemal, and eight coiled-coils. The vesicular traffic proteins detected were Mu adaptin, Vacuolar ATP synthase subunit B, Bip, Sec61 alpha, NSF, AP complex subunit beta, and dynamin. These results indicate that CLP259 in trophozoites is a CSK linker protein for actin and tubulin and could act as a scaffold protein driving vesicular traffic.
Assuntos
Actinas/metabolismo , Giardia lamblia/metabolismo , Plaquinas/metabolismo , Tubulina (Proteína)/metabolismo , Actinas/química , Sequência de Aminoácidos , Animais , Anquirinas/química , Sequência de Bases , Western Blotting , Biologia Computacional , Sequência Consenso , Citoplasma/química , Citoesqueleto/química , Citoesqueleto/fisiologia , Citoesqueleto/ultraestrutura , Dinaminas/análise , Feminino , Imunofluorescência , Giardia lamblia/química , Giardia lamblia/ultraestrutura , Humanos , Imunoprecipitação , Camundongos , Camundongos Endogâmicos BALB C , Microscopia Confocal , Plaquinas/química , Alinhamento de Sequência , Tubulina (Proteína)/químicaRESUMO
BACKGROUND: To deeply understand the role of antibodies in the context of Trypanosoma cruzi infection, we decided to characterize A2R1, a parasite antibody selected from single-chain variable fragment (scFv) phage display libraries constructed from B cells of chronic Chagas heart disease patients. METHODS: Immunoblot, ELISA, cytometry, immunofluorescence and immunohistochemical assays were used to characterize A2R1 reactivity. To identify the antibody target, we performed an immunoprecipitation and two-dimensional electrophoresis coupled to mass spectrometry and confirmed A2R1 specific interaction by producing the antigen in different expression systems. Based on these data, we carried out a comparative in silico analysis of the protein target´s orthologues, focusing mainly on post-translational modifications. FINDINGS: A2R1 recognizes a parasite protein of ~50 kDa present in all life cycle stages of T. cruzi, as well as in other members of the kinetoplastid family, showing a defined immunofluorescence labeling pattern consistent with the cytoskeleton. A2R1 binds to tubulin, but this interaction relies on its post-translational modifications. Interestingly, this antibody also targets mammalian tubulin only present in brain, staining in and around cell bodies of the human peripheral and central nervous system. INTERPRETATION: Our findings demonstrate for the first time the existence of a human antibody against T. cruzi tubulin capable of cross-reacting with a human neural protein. This work re-emphasizes the role of molecular mimicry between host and parasitic antigens in the development of pathological manifestations of T. cruzi infection.
Assuntos
Anticorpos Monoclonais/farmacologia , Anticorpos Antiprotozoários/farmacologia , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Proteínas Recombinantes de Fusão/farmacologia , Trypanosoma cruzi/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/uso terapêutico , Anticorpos Antiprotozoários/imunologia , Anticorpos Antiprotozoários/uso terapêutico , Especificidade de Anticorpos/imunologia , Antígenos de Protozoários/imunologia , Linhagem Celular , Clonagem Molecular , Reações Cruzadas/imunologia , Desenvolvimento de Medicamentos , Ensaio de Imunoadsorção Enzimática , Escherichia coli/genética , Escherichia coli/metabolismo , Imunofluorescência , Expressão Gênica , Humanos , Imunoprecipitação , Espectrometria de Massas , Camundongos , Mimetismo Molecular , Ratos , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/uso terapêutico , Análise de Sequência de DNA , Anticorpos de Cadeia Única/imunologia , Anticorpos de Cadeia Única/farmacologia , Anticorpos de Cadeia Única/uso terapêuticoRESUMO
Macroautophagy/autophagy is an intracellular process involved in the breakdown of macromolecules and organelles. Recent studies have shown that PKD2/PC2/TRPP2 (polycystin 2, transient receptor potential cation channel), a nonselective cation channel permeable to Ca2+ that belongs to the family of transient receptor potential channels, is required for autophagy in multiple cell types by a mechanism that remains unclear. Here, we report that PKD2 forms a protein complex with BECN1 (beclin 1), a key protein required for the formation of autophagic vacuoles, by acting as a scaffold that interacts with several co-modulators via its coiled-coil domain (CCD). Our data identified a physical and functional interaction between PKD2 and BECN1, which depends on one out of two CCD domains (CC1), located in the carboxy-terminal tail of PKD2. In addition, depletion of intracellular Ca2+ with BAPTA-AM not only blunted starvation-induced autophagy but also disrupted the PKD2-BECN1 complex. Consistently, PKD2 overexpression triggered autophagy by increasing its interaction with BECN1, while overexpression of PKD2D509V, a Ca2+ channel activity-deficient mutant, did not induce autophagy and manifested diminished interaction with BECN1. Our findings show that the PKD2-BECN1 complex is required for the induction of autophagy, and its formation depends on the presence of the CC1 domain of PKD2 and on intracellular Ca2+ mobilization by PKD2. These results provide new insights regarding the molecular mechanisms by which PKD2 controls autophagy.Abbreviations: ADPKD: autosomal dominant polycystic kidney disease; ATG: autophagy-related; ATG14/ATG14L: autophagy related 14; Baf A1: bafilomycin A1; BCL2/Bcl-2: BCL2 apoptosis regulator; BCL2L1/BCL-XL: BCL2 like 1; BECN1: beclin 1; CCD: coiled-coil domain; EBSS: Earle's balanced salt solution; ER: endoplasmic reticulum; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GFP: green fluorescent protein; GOLGA2/GM130: golgin A2; GST: glutathione s-transferase; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTORC1: mechanistic target of rapamycin kinase complex 1; NBR1: NBR1 autophagy cargo receptor; PIK3C3/VPS34: phosphatidylinositol 3-kinase catalytic subunit type 3; PKD2/PC2: polycystin 2, transient receptor potential cation channel; RTN4/NOGO: reticulon 4; RUBCN/RUBICON: rubicon autophagy regulator; SQSTM1/p62: sequestosome 1; UVRAG: UV radiation resistance associated; WIPI2: WD repeat domain, phosphoinositide interacting 2.
Assuntos
Autofagia , Proteína Beclina-1/fisiologia , Canais de Cátion TRPP/fisiologia , Proteína Beclina-1/metabolismo , Western Blotting , Imunofluorescência , Células HEK293 , Células HeLa , Humanos , Imunoprecipitação , Canais de Cátion TRPP/metabolismoRESUMO
PURPOSE: Increasing evidence suggested that microRNA plays an important role in ovarian cancer. In this study, the role of miR-92 in ovarian cancer was investigated. METHODS: In this study, miR-92 expression in clinical sample was evaluated, role of miR-92 was investigated in vitro, and underlying mechanism was investigated using Chip, co-IP, and western blot. RESULTS: In this study, we show that miR-92 is overexpressed in ovarian cancer tissue compared with normal cancer tissue. Transfection of miR-92 increased proliferation of ovarian cancer cell, and increased migration capacity and colony formation were observed after miR-92 transfection; we found that expression of LATS2 was decreased by miR-92, and this was further confirmed by luciferase assay, which proved that miR-92 is targeting 3' of the endogenous LATS2 gene. Downregulation of LATS2 resulted in increased translocation of YAP1 and upregulation of PD-L1, which subsequently suppressed NK cell function and promoted T cell apoptosis. Moreover, co-transfection of YAP1-targeted shRNA could relieve miR-92-induced immune suppression effect. Mechanically, immunoprecipitation (IP) was used to show that LATS2 interacted with YAP1 and subsequently limited nuclear translocation of YAP1; chromatin immunoprecipitation (ChIP) was used to confirm that YAP1 could bind to enhancer region of PD-L1 to enhance transcription activity of PD-L1. CONCLUSIONS: Our data revealed a novel mechanism which finally resulted in immune suppression in ovarian cancer.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Antígeno B7-H1/metabolismo , Células Matadoras Naturais/imunologia , MicroRNAs/metabolismo , Neoplasias Ovarianas/imunologia , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Apoptose , Linhagem Celular Tumoral , Movimento Celular , Núcleo Celular/metabolismo , Proliferação de Células , Regulação para Baixo , Elementos Facilitadores Genéticos , Feminino , Inativação Gênica , Humanos , Imunidade Celular , Imunoprecipitação , Células-Tronco Neoplásicas , Neoplasias Ovarianas/metabolismo , Neoplasias Ovarianas/patologia , Proteínas Serina-Treonina Quinases/genética , RNA Interferente Pequeno , Transdução de Sinais , Linfócitos T/fisiologia , Proteínas Supressoras de Tumor/genética , Regulação para Cima , Proteínas de Sinalização YAPRESUMO
PURPOSE: The current study aims to explore the effects of CDKN2A on cell proliferation and cycle, and investigate the underlying mechanisms. METHODS: Expression of CDKN2A in cervical cancer cell lines was evaluated by real-time quantitative PCR (RT-qPCR) and western blotting. Apoptotic rate was detected by Annexin V assay. MTT assay, Transwell assay and cell cycle assay kit were applied to examine the effect of CDKN2A on cell viability, invasion and cell cycle. Co-immunoprecipitation and western blotting were devoted to explore the mechanism by which CDKN2A contributes to cell function. RESULTS: CDKN2A was expressed at a low level in cervical cancer cell lines. Overexpression of CDKN2A inhibited cell proliferation and invasion, and caused cell cycle arrest in the G1 phase. CDKN2A mediates the AKT-mTOR signaling pathway by suppressing lactate dehydrogenase (LDHA). Taken together, our data revealed that CDKN2A can be applied as a therapeutic target for the treatment of cervical cancer in future. CONCLUSIONS: CDKN2A inhibits cell proliferation and invasion in cervical cancer through LDHA-mediated AKT-mTOR pathway.
Assuntos
Proliferação de Células/fisiologia , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , L-Lactato Desidrogenase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Neoplasias do Colo do Útero/metabolismo , Apoptose/fisiologia , Linhagem Celular Tumoral , Sobrevivência Celular/fisiologia , Regulação para Baixo/fisiologia , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular , Células HeLa , Humanos , Imunoprecipitação , Invasividade Neoplásica , Neoplasias do Colo do Útero/patologiaRESUMO
Atherosclerosis (AS) is a common vascular disease, which can cause apoptosis of vascular endothelial cells. Notoginsenoside R1 (NGR1) is considered an anti-AS drug. MicroRNAs (miRNAs) are believed to play a vital role in cell apoptosis and angiogenesis. This study aimed to explore the mechanism of NGR1 for treating AS through miRNAs. Flow cytometry was used to detect the apoptosis rate. The levels of inflammatory cytokines interleukin (IL)-6 and IL-1ß were detected using ELISA. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were measured using corresponding assay kits. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to detect miR-221-3p expression. Dual-luciferase reporter and RNA immunoprecipitation assays were carried out to examine the relationship between miR-221-3p and toll-like receptors 4 (TLR4). Also, western blot analysis was performed to determine the levels of TLR4 and nuclear factor kappa B (NF-κB) signaling pathway-related proteins. Oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cells (HUVECs) apoptosis, inflammation, and oxidative stress. NGR1 alleviated the negative effect of ox-LDL through promoting the expression of miR-221-3p in HUVECs. TLR4 was a target of miR-221-3p, and its overexpression could reverse the inhibition effects of miR-221-3p on apoptosis, inflammation, and oxidative stress. NGR1 improved miR-221-3p expression to inhibit the activation of the TLR4/NF-κB pathway in ox-LDL-treated HUVECs. NGR1 decreased ox-LDL-induced HUVECs apoptosis, inflammation, and oxidative stress through increasing miR-221-3p expression, thereby inhibiting the activation of the TLR4/NF-κB pathway. This study of the mechanism of NGR1 provided a more theoretical basis for the treatment of AS.
Assuntos
Apoptose/efeitos dos fármacos , Ginsenosídeos/farmacologia , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Inflamação/metabolismo , Lipoproteínas LDL/metabolismo , MicroRNAs/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Western Blotting , Ensaio de Imunoadsorção Enzimática , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Imunoprecipitação , MicroRNAs/metabolismo , NF-kappa B/antagonistas & inibidores , Espécies Reativas de Oxigênio , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais , Receptor 4 Toll-Like/antagonistas & inibidores , Ativação Transcricional , Regulação para CimaRESUMO
Immunoprecipitation is a helpful tool to assess interactions between proteins and proteins or nucleic acids (DNA or RNA). Its principle consists in capturing and enriching one or multiple target proteins from a complex sample with a specific antibody conjugated to a solid matrix and isolating the RNA and/or protein molecules associated to those target(s) group of proteins that can be further identified by advanced techniques such as RNA-seq and/or mass spectrometry. Since this technique allows for identifying, mapping, and checking new protein-protein and protein-RNA interactions, its use is very convenient in situations where many proteins remain with their functions uncharacterized, as is the case of the protozoan Trypanosoma cruzi. Here we describe a protocol that is based on the cryogrinding method for cell lysis and the use of antibodies conjugated to magnetic beads to capture and purify protein complexes in a robust and efficient way.
Assuntos
Separação Imunomagnética/métodos , Imunoprecipitação/métodos , Substâncias Macromoleculares/isolamento & purificação , Trypanosoma cruzi/fisiologia , Substâncias Macromoleculares/metabolismo , Espectrometria de Massas/métodos , Parasitologia/métodos , Mapeamento de Interação de Proteínas , Proteínas de Protozoários/isolamento & purificação , Proteínas de Protozoários/metabolismo , RNA de Protozoário/isolamento & purificação , RNA de Protozoário/metabolismoRESUMO
Chronic kidney disease (CKD) causes anemia by renal damage. In CKD, the kidney is submitted to hypoxia, persistent inflammation, leading to fibrosis and permanent loss of renal function. Human recombinant erythropoietin (rEPO) has been widely used to treat CKD-associated anemia and is known to possess organ-protective properties that are independent from its well-established hematopoietic effects. Nonhematopoietic effects of EPO are mediated by an alternative receptor that is proposed to consist of a heterocomplex between the erythropoietin receptor (EPOR) and the beta common receptor (ßcR). The present study explored the effects of rEPO to prevent renal fibrosis in adenine-induced chronic kidney disease (Ad-CKD) and their association with the expression of the heterodimer EPOR/ßcR. Male Wistar rats were randomized to control group (CTL), adenine-fed rats (Ad-CKD), and Ad-CKD with treatment of rEPO (1050 IU/kg, once weekly for 4 weeks). Ad-CKD rats exhibited anemia, uremia, decreased renal function, increased infiltration of inflammatory cells, tubular atrophy, and fibrosis. rEPO treatment not only corrected anemia but reduced uremia and partially improved renal function as well. In addition, we observed that rEPO diminishes tubular injury, prevents fibrosis deposition, and induces the EPOR/ßcR heteroreceptor. The findings may explain the extrahematopoietic effects of rEPO in CKD and provide new strategies for the treatment of renal fibrosis in CKD.
Assuntos
Fibrose/metabolismo , Fibrose/prevenção & controle , Insuficiência Renal Crônica/induzido quimicamente , Insuficiência Renal Crônica/tratamento farmacológico , Animais , Western Blotting , Eritropoetina/uso terapêutico , Imunofluorescência , Humanos , Imunoprecipitação , Masculino , Ratos , Ratos Wistar , Reação em Cadeia da Polimerase em Tempo Real , Receptores da Eritropoetina/metabolismo , Proteínas Recombinantes/uso terapêuticoRESUMO
OBJECTIVES: Xerostomia in SS patients has been associated with low quality and quantity of salivary mucins, which are fundamental for the hydration and protection of the oral mucosa. The aim of this study was to evaluate if cytokines induce aberrant mucin expression and whether tauroursodeoxycholic acid (TUDCA) is able to counteract such an anomaly. METHODS: Labial salivary glands from 16 SS patients and 15 control subjects, as well as 3D acini or human submandibular gland cells stimulated with TNF-α or IFN-γ and co-incubated with TUDCA, were analysed. mRNA and protein levels of Mucin 1 (MUC1) and MUC7 were determined by RT-qPCR and western blot, respectively. Co-immunoprecipitation and immunofluorescence assays for mucins and GRP78 [an endoplasmic reticulum (ER)-resident protein] were also performed. mRNA levels of RelA/p65 (nuclear factor-κB subunit), TNF-α, IL-1ß, IL-6, SEL1L and EDEM1 were determined by RT-qPCR, and RelA/p65 localization was evaluated by immunofluorescence. RESULTS: MUC1 is overexpressed and accumulated in the ER of labial salivary gland from SS patients, while MUC7 accumulates throughout the cytoplasm of acinar cells; however, MUC1, but not MUC7, co-precipitated with GRP78. TUDCA diminished the overexpression and aberrant accumulation of MUC1 induced by TNF-α and IFN-γ, as well as the nuclear translocation of RelA/p65, together with the expression of inflammatory and ER stress markers in 3D acini. CONCLUSION: Chronic inflammation alters the secretory process of MUC1, inducing ER stress and affecting the quality of saliva in SS patients. TUDCA showed anti-inflammatory properties decreasing aberrant MUC1 accumulation. Further studies are necessary to evaluate the potential therapeutic effect of TUDCA in restoring glandular homeostasis in SS patients.
Assuntos
Células Acinares/efeitos dos fármacos , Estresse do Retículo Endoplasmático/efeitos dos fármacos , Mucina-1/efeitos dos fármacos , Glândulas Salivares Menores/efeitos dos fármacos , Síndrome de Sjogren/metabolismo , Glândula Submandibular/efeitos dos fármacos , Ácido Tauroquenodesoxicólico/farmacologia , Xerostomia/metabolismo , Células Acinares/metabolismo , Adulto , Idoso , Estudos de Casos e Controles , Células Cultivadas , Chaperona BiP do Retículo Endoplasmático , Estresse do Retículo Endoplasmático/genética , Feminino , Proteínas de Choque Térmico/efeitos dos fármacos , Proteínas de Choque Térmico/genética , Proteínas de Choque Térmico/metabolismo , Humanos , Imunoprecipitação , Técnicas In Vitro , Interferon gama/farmacologia , Interleucina-1beta/efeitos dos fármacos , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Interleucina-6/genética , Interleucina-6/metabolismo , Masculino , Proteínas de Membrana/efeitos dos fármacos , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Pessoa de Meia-Idade , Mucina-1/genética , Mucina-1/metabolismo , Mucinas/efeitos dos fármacos , Mucinas/genética , Mucinas/metabolismo , Proteínas/efeitos dos fármacos , Proteínas/genética , Proteínas/metabolismo , RNA Mensageiro/efeitos dos fármacos , RNA Mensageiro/metabolismo , Glândulas Salivares Menores/metabolismo , Proteínas e Peptídeos Salivares/efeitos dos fármacos , Proteínas e Peptídeos Salivares/genética , Proteínas e Peptídeos Salivares/metabolismo , Síndrome de Sjogren/genética , Glândula Submandibular/citologia , Glândula Submandibular/metabolismo , Fator de Transcrição RelA/efeitos dos fármacos , Fator de Transcrição RelA/genética , Fator de Transcrição RelA/metabolismo , Fator de Necrose Tumoral alfa/efeitos dos fármacos , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Fator de Necrose Tumoral alfa/farmacologia , Xerostomia/genéticaRESUMO
Atherosclerosis (AS) is a common vascular disease, which can cause apoptosis of vascular endothelial cells. Notoginsenoside R1 (NGR1) is considered an anti-AS drug. MicroRNAs (miRNAs) are believed to play a vital role in cell apoptosis and angiogenesis. This study aimed to explore the mechanism of NGR1 for treating AS through miRNAs. Flow cytometry was used to detect the apoptosis rate. The levels of inflammatory cytokines interleukin (IL)-6 and IL-1β were detected using ELISA. Reactive oxygen species (ROS) and malondialdehyde (MDA) levels were measured using corresponding assay kits. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was performed to detect miR-221-3p expression. Dual-luciferase reporter and RNA immunoprecipitation assays were carried out to examine the relationship between miR-221-3p and toll-like receptors 4 (TLR4). Also, western blot analysis was performed to determine the levels of TLR4 and nuclear factor kappa B (NF-κB) signaling pathway-related proteins. Oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cells (HUVECs) apoptosis, inflammation, and oxidative stress. NGR1 alleviated the negative effect of ox-LDL through promoting the expression of miR-221-3p in HUVECs. TLR4 was a target of miR-221-3p, and its overexpression could reverse the inhibition effects of miR-221-3p on apoptosis, inflammation, and oxidative stress. NGR1 improved miR-221-3p expression to inhibit the activation of the TLR4/NF-κB pathway in ox-LDL-treated HUVECs. NGR1 decreased ox-LDL-induced HUVECs apoptosis, inflammation, and oxidative stress through increasing miR-221-3p expression, thereby inhibiting the activation of the TLR4/NF-κB pathway. This study of the mechanism of NGR1 provided a more theoretical basis for the treatment of AS.
Assuntos
Humanos , Apoptose/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Ginsenosídeos/farmacologia , MicroRNAs/efeitos adversos , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Inflamação/metabolismo , Lipoproteínas LDL/metabolismo , Ensaio de Imunoadsorção Enzimática , Transdução de Sinais , Ativação Transcricional , Regulação para Cima , Western Blotting , NF-kappa B/antagonistas & inibidores , Espécies Reativas de Oxigênio , MicroRNAs/metabolismo , Imunoprecipitação , Receptor 4 Toll-Like/antagonistas & inibidores , Células Endoteliais da Veia Umbilical Humana/metabolismo , Reação em Cadeia da Polimerase em Tempo RealRESUMO
BACKGROUND/AIMS: Cyclophilin D (CypD) mediates the mitochondrial permeability transition pore (mPTP) opening that contributes to mitochondrial dysfunction. CypD is regulated by its acetylation/deacetylation state that depends on Sirtuin-3 (SIRT3) mitochondrial deacetylase. Since obesity and metabolic syndrome decrease SIRT3 activity and expression, we tested the hypothesis that CypD hyperacetylation promotes mitochondrial dysfunction under this pathophysiological state, which is associated with ventricular dysfunction and heart failure. METHODS: Myocardial tissue samples from patients with left ventricular heart failure, with either obesity or normal weight, were processed for the expression of SIRT3 and acetylation profile by Western Blot (WB). In addition, a rat model of obesity and metabolic syndrome induced by 30% (w/v) of sucrose was conducted. The WB analysis was used to determine the levels of mitochondrial expression of SIRT3, Adenine Nucleotide Translocator (ANT), CypD and the acetylation profile, as well as immunoprecipitation to establish the acetylation levels of CypD. Mitochondrial function was assessed by oxygen consumption analysis and maximum Ca2+ retention capacity. Oxidative stress was assessed by aconitase activity, protein carbonyl and thiol groups content. RESULTS: SIRT3 expression in the biopsies of the failing human hearts showed a 46% decrease in the expression levels of obese patients in comparison to the non-obese patients (p=0.0219). Remarkably, body mass index was associated with protein acetylation (0.627; p = 0.035), suggesting that the acetylation profiles of the failing hearts of obese patients are partly mediated by a reduction in SIRT3, which is also associated with higher BNP levels, indicating a more severe ventricular dysfunction (-0.636; p = 0.043). Accordingly, obese rats demonstrated a SIRT3 mitochondrial expression decrease of 22% concomitantly with a hyperacetylated mitochondrial profile, including CypD. Cardiac mitochondria from obese animals were 2.5-fold more prone to mPTP opening than the controls. CONCLUSION: Our results indicate that obesity reduces SIRT3 expression and that CypD hyperacetylation increases mPTP opening, suggesting that the activation of SIRT3 might be a potential target to decrease ventricular dysfunction and slow the progression of heart failure.
Assuntos
Mitocôndrias Cardíacas/metabolismo , Proteínas de Transporte da Membrana Mitocondrial/metabolismo , Obesidade/metabolismo , Sirtuína 3/metabolismo , Acetilação , Adulto , Idoso , Animais , Índice de Massa Corporal , Cálcio/metabolismo , Peptidil-Prolil Isomerase F , Ciclofilinas/metabolismo , Feminino , Insuficiência Cardíaca/metabolismo , Humanos , Imunoprecipitação , Técnicas In Vitro , Masculino , Síndrome Metabólica/metabolismo , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Translocases Mitocondriais de ADP e ATP/metabolismo , Poro de Transição de Permeabilidade Mitocondrial , Consumo de Oxigênio/fisiologia , Ratos , Ratos WistarRESUMO
Toxoplasma gondii is an important human and veterinary pathogen and the causative agent of toxoplasmosis, a potentially severe disease especially in immunocompromised or congenitally infected humans. Current therapeutic compounds are not well-tolerated, present increasing resistance, limited efficacy and require long periods of treatment. On this context, searching for new therapeutic targets is crucial to drug discovery. In this sense, recent works suggest that N-myristoyltransferase (NMT), the enzyme responsible for protein myristoylation that is essential in some parasites, could be the target of new anti-parasitic compounds. However, up to date there is no information on NMT and the extent of this modification in T. gondii. In this work, we decided to explore T. gondii genome in search of elements related with the N-myristoylation process. By a bioinformatics approach it was possible to identify a putative T. gondii NMT (TgNMT). This enzyme that is homologous to other parasitic NMTs, presents activity in vitro, is expressed in both intra- and extracellular parasites and interacts with predicted TgNMT substrates. Additionally, NMT activity seems to be important for the lytic cycle of Toxoplasma gondii. In parallel, an in silico myristoylome predicts 157 proteins to be affected by this modification. Myristoylated proteins would be affecting several metabolic functions with some of them being critical for the life cycle of this parasite. Together, these data indicate that TgNMT could be an interesting target of intervention for the treatment of toxoplasmosis.