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1.
Se Pu ; 39(10): 1086-1093, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34505430

RESUMO

Many secreted proteins, including cytokines, growth factors and hormones, are crucial in processes like intercellular signaling. Dynamic changes in secreted proteins usually reflect the growth and pathological state of the cells. Many drug targets are secretory proteins. The proteins are also important biomarkers. Conditioned cell culture media are important samples for secretory proteomic studies. Biomass spectrometry-based proteomic analysis enables the systematic study of secretory proteins. The main problem in analyzing secretory proteins in conditioned culture media is the low concentration of these proteins and the presence of serum, amino acids, and additives in culture media that may interfere with the protein analysis. Conventional secretory proteome analysis uses serum-free cell culture to reduce sample complexity, and typically involves protein concentration, purification, and desalting using ultrafiltration, dialysis, lyophilization, and trichloroacetic acid (TCA) or acetone precipitation, followed by enzymatic digestion and mass spectrometry analysis. This analytical process does not allow specific enrichment of secreted proteins. Thus, only a few secreted proteins can be identified. In addition, prolonged serum-free incubation of cells also tends to lead to unexpected changes in their activity status. A bioorthogonal-based enrichment approach can effectively avoid this problem. In recent years, unnatural sugars containing bio-orthologous groups, such as azide groups, have been used to metabolically label glycosylated proteins, enabling cellular imaging or selective enrichment of glycoproteins and their use for proteomic analysis. The strategy is a two-step process. First, azide-based sugar analogues are added to the cell culture medium and introduced to glycoproteins via the intracellular glycan biosynthesis pathway. Second, they are specifically covalently labeled with imaging probes or affinity probes via click chemistry. Since secreted proteins are usually glycoproteins, this glycolytic labeling has been used to label and enrich secreted proteins. N-Azidoacetylgalactosamine (GalNAz), N-azidoacetylglucosamine (GlcNAz), and N-azidoacetylmannosamine (ManNAz) are classical azide-based sugar analogues. Their effects on cytoplasmic membrane proteins have been compared. However, only ManNAz has been used for metabolic labeling of secreted proteins. No other glyco-analogues that label secreted proteins have been reported. Here, the bio-orthogonal chemical biology technology achieved highly selective labeling and enriched secreted proteins. In combination with click chemistry, different sugar analogues were evaluated for metabolic labeling of secreted proteins. HeLa cells were metabolically labeled by ManNAz, GalNAz, and GlcNAz (the three most commonly used commercial sugar analogues). These glycolytic markers can selectively label specific types of glycosylation. For example, ManNAz, an analogue of the biosynthetic precursor of sialic acid, N-acetylmannosamine (ManNAc), can label sialylated N- or O-glycoproteins. GalNAz, an analogue of N-acetylgalactosamine (GalNAc), can replace GalNAc as a core residue of mucin-type O-glycans and thus label O-glycoproteins. In addition, the intracellular metabolic intermediate of GalNAz (pyrophosphate) UDP-GalNAz can be interconverted with UDP-GlcNAz catalyzed by UDP-galactose-4-differential isomerase (GALE) and thus can also label N-glycoproteins and O-GlcNAc glycoproteins instead of GlcNAc. The GlcNAz analogue is commonly used to label nuclear and cytoplasmic glycoproteins with β-O-GlcNAc residues, but can also label N-glycoproteins with mucin-type O-glycoproteins by converting GALE to GalNAz, followed by enrichment using a biotin-alkynyl probe. Label-free quantitative proteomic analysis was performed to evaluate their labeling efficiency. ManNAz-based secretory protein labeling identified 282 secretory proteins, 224 plasma membrane proteins, and 846 N-glycosites. Compared with GalNAz and GlcNAz, the enrichment of secreted proteins was increased 130% and 67.2%, respectively, and the enrichment of plasma membrane proteins was increased 273.3% and 148.7%, respectively. This study provides a useful comparative analysis and new strategies for highly selective enrichment and systematic secretome analysis.


Assuntos
Proteômica , Açúcares , Glicoproteínas , Glicosilação , Células HeLa , Humanos
2.
Mater Sci Eng C Mater Biol Appl ; 128: 112314, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34474865

RESUMO

We used an in situ chemical oxidation method to prepare a new composite of silver nanoparticles (AgNPs) with polypyrrole (PPy), whose properties were optimized through a 23-factorial design of the synthesis conditions. The successful formation of the AgNPs/PPy composite was confirmed by UV-Visible and FTIR spectroscopies. Transmission electron microscopy revealed the presence of AgNPs smaller than 100 nm, dispersed into the PPy matrix. This hybrid composite exhibits a blue fluorescence emission after excitation in the ultraviolet region. In MTT assays, the AgNPs/PPy composite exhibited low cytotoxicity toward non-tumoral cell lines (fibroblast, Vero, and macrophages) and selectively inhibited the viability of HeLa cells. The AgNPs/PPy composite induces ultrastructural changes in HeLa cells that are consistent with the noticeable selectivity exhibited toward them when compared to its action against non-tumoral cell lineages. Also, the AgNPs/PPy exhibited a hemolytic activity below 14% for all blood groups tested, at concentrations up to 125 µg/mL. These results suggest that the AgNPs/PPy composite has a promising potential for use as an antitumoral agent.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos , Células HeLa , Humanos , Polímeros , Pirróis/farmacologia
3.
Nanoscale ; 13(31): 13294-13300, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477735

RESUMO

Successful delivery of fluorescent nanodiamonds (FNDs) into the cytoplasm is essential to many biological applications. Other applications require FNDs to stay within the endosomes. The diversity of cellular uptake of FNDs and following endosomal escape are less explored. In this article, we quantify particle uptake at a single cell level. We report that FNDs enter into the cells gradually. The number of internalized FNDs per cell differs significantly for the cell lines we investigated at the same incubation time. In HeLa cells we do not see any significant endosomal escape. We also found a wide distribution of FND endosomal escape efficiency within the same cell type. However, compared with HeLa cells, FNDs in HUVECs can easily escape from the endosomes and less than 25% FNDs remained in the vesicles after 4 h incubation time. We believe this work can bring more attention to the diversity of the cells and provide potential guidelines for future studies.


Assuntos
Nanodiamantes , Endossomos , Corantes Fluorescentes , Células HeLa , Humanos
4.
Int J Mol Sci ; 22(16)2021 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-34445214

RESUMO

Deubiquitinating enzymes play key roles in the precise modulation of Aurora B-an essential cell cycle regulator. The expression of Aurora B increases before the onset of mitosis and decreases during mitotic exit; an imbalance in these levels has a severe impact on the fate of the cell cycle. Dysregulation of Aurora B can lead to aberrant chromosomal segregation and accumulation of errors during mitosis, eventually resulting in cytokinesis failure. Thus, it is essential to identify the precise regulatory mechanisms that modulate Aurora B levels during the cell division cycle. Using a deubiquitinase knockout strategy, we identified USP48 as an important candidate that can regulate Aurora B protein levels during the normal cell cycle. Here, we report that USP48 interacts with and stabilizes the Aurora B protein. Furthermore, we showed that the deubiquitinating activity of USP48 helps to maintain the steady-state levels of Aurora B protein by regulating its half-life. Finally, USP48 knockout resulted in delayed progression of cell cycle due to accumulation of mitotic defects and ultimately cytokinesis failure, suggesting the role of USP48 in cell cycle regulation.


Assuntos
Aurora Quinase B/metabolismo , Citocinese , Mitose , Proteases Específicas de Ubiquitina/metabolismo , Aurora Quinase B/genética , Estabilidade Enzimática , Células HEK293 , Células HeLa , Humanos , Proteases Específicas de Ubiquitina/genética
5.
Int J Mol Sci ; 22(16)2021 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-34445405

RESUMO

Persistent HPV (Human Papillomavirus) infection is the primary cause of cervical cancer. Despite the development of the HPV vaccine to prevent infections, cervical cancer is still a fatal malignant tumor and metastatic disease, and it is often difficult to treat, so a new treatment strategy is needed. The FDA-approved drug Bazedoxifene is a novel inhibitor of protein-protein interactions between IL-6 and GP130. Multiple ligand simultaneous docking and drug repositioning approaches have demonstrated that an IL-6/GP130 inhibitor can act as a selective estrogen modulator. However, the molecular basis for GP130 activation in cervical cancer remains unclear. In this study, we investigated the anticancer properties of Bazedoxifene in HPV-positive cervical cancer cells. In vitro and in vivo experiments showed that Bazedoxifene inhibited cell invasion, migration, colony formation, and tumor growth in cervical cancer cells. We also confirmed that Bazedoxifene inhibits the GP130/STAT3 pathway and suppresses the EMT (Epithelial-mesenchymal transition) sub-signal. Thus, these data not only suggest a molecular mechanism by which the GP130/STAT3 pathway may promote cancer, but also may provide a basis for cervical cancer replacement therapy.


Assuntos
Receptor gp130 de Citocina/metabolismo , Indóis/administração & dosagem , Interleucina-6/metabolismo , Infecções por Papillomavirus/tratamento farmacológico , Neoplasias do Colo do Útero/tratamento farmacológico , Neoplasias do Colo do Útero/virologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Reposicionamento de Medicamentos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Feminino , Células HeLa , Humanos , Indóis/farmacologia , Camundongos , Camundongos Nus , Infecções por Papillomavirus/metabolismo , Fosforilação/efeitos dos fármacos , Mapas de Interação de Proteínas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Neoplasias do Colo do Útero/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto
6.
mBio ; 12(4): e0159021, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34340537

RESUMO

Selective pressures drive adaptive changes in the coronavirus spike proteins directing virus-cell entry. These changes are concentrated in the amino-terminal domains (NTDs) and the receptor-binding domains (RBDs) of complex modular spike protein trimers. The impact of this hypervariability on virus entry is often unclear, particularly with respect to sarbecovirus NTD variations. Therefore, we constructed indels and substitutions within hypervariable NTD regions and used severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus-like particles and quantitative virus-cell entry assays to elucidate spike structures controlling this initial infection stage. We identified NTD variations that increased SARS-CoV-2 spike protein-mediated membrane fusion and cell entry. Increased cell entry correlated with greater presentation of RBDs to ACE2 receptors. This revealed a significant allosteric effect, in that changes within the NTDs can orient RBDs for effective virus-cell binding. Yet, those NTD changes elevating receptor binding and membrane fusion also reduced interdomain associations, leaving spikes on virus-like particles susceptible to irreversible inactivation. These findings parallel those obtained decades ago, in which comparisons of murine coronavirus spike protein variants established inverse relationships between membrane fusion potential and virus stability. Considerable hypervariability in the SARS-CoV-2 spike protein NTDs also appear to be driven by counterbalancing pressures for effective virus-cell entry and durable extracellular virus infectivity. These forces may selectively amplify SARS-CoV-2 variants of concern. IMPORTANCE Adaptive changes that increase SARS-CoV-2 transmissibility may expand and prolong the coronavirus disease 2019 (COVID-19) pandemic. Transmission requires metastable and dynamic spike proteins that bind viruses to cells and catalyze virus-cell membrane fusion. Using newly developed assays reflecting these two essential steps in virus-cell entry, we focused on adaptive changes in SARS-CoV-2 spike proteins and found that deletions in amino-terminal domains reset spike protein metastability, rendering viruses less stable yet more poised to respond to cellular factors that prompt entry and subsequent infection. The results identify adjustable control features that balance extracellular virus stability with facile virus dynamics during cell entry. These equilibrating elements warrant attention when monitoring the evolution of pandemic coronaviruses.


Assuntos
COVID-19/transmissão , SARS-CoV-2/genética , Glicoproteína da Espícula de Coronavírus/genética , Internalização do Vírus , Enzima de Conversão de Angiotensina 2/metabolismo , COVID-19/patologia , Linhagem Celular Tumoral , Células HEK293 , Células HeLa , Humanos , Fusão de Membrana/fisiologia , Domínios Proteicos/fisiologia , Receptores Virais/metabolismo , Glicoproteína da Espícula de Coronavírus/metabolismo
7.
Nat Commun ; 12(1): 4883, 2021 08 12.
Artigo em Inglês | MEDLINE | ID: mdl-34385449

RESUMO

Pure organic room-temperature phosphorescent (RTP) materials have been suggested to be promising bioimaging materials due to their good biocompatibility and long emission lifetime. Herein, we report a class of RTP materials. These materials are developed through the simple introduction of an aromatic carbonyl to a tetraphenylpyrrole molecule and also exhibit aggregation-induced emission (AIE) properties. These molecules show non-emission in solution and purely phosphorescent emission in the aggregated state, which are desirable properties for biological imaging. Highly crystalline nanoparticles can be easily fabricated with a long emission lifetime (20 µs), which eliminate background fluorescence interference from cells and tissues. The prepared nanoparticles demonstrate two-photon absorption characteristics and can be excited by near infrared (NIR) light, making them promising materials for deep-tissue optical imaging. This integrated aggregation-induced phosphorescence (AIP) strategy diversifies the existing pool of bioimaging agents to inspire the development of bioprobes in the future.


Assuntos
Corantes Fluorescentes/química , Luminescência , Microscopia de Fluorescência por Excitação Multifotônica/métodos , Nanopartículas/química , Pirróis/química , Imagem com Lapso de Tempo/métodos , Animais , Células HeLa , Humanos , Camundongos Endogâmicos BALB C , Camundongos Nus , Microscopia Confocal/métodos , Microscopia Eletrônica de Transmissão/métodos , Nanopartículas/ultraestrutura , Tamanho da Partícula
8.
Nat Commun ; 12(1): 4919, 2021 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-34389725

RESUMO

BRCA1 or BRCA2 germline mutations predispose to breast, ovarian and other cancers. High-throughput sequencing of tumour genomes revealed that oncogene amplification and BRCA1/2 mutations are mutually exclusive in cancer, however the molecular mechanism underlying this incompatibility remains unknown. Here, we report that activation of ß-catenin, an oncogene of the WNT signalling pathway, inhibits proliferation of BRCA1/2-deficient cells. RNA-seq analyses revealed ß-catenin-induced discrete transcriptome alterations in BRCA2-deficient cells, including suppression of CDKN1A gene encoding the CDK inhibitor p21. This accelerates G1/S transition, triggering illegitimate origin firing and DNA damage. In addition, ß-catenin activation accelerates replication fork progression in BRCA2-deficient cells, which is critically dependent on p21 downregulation. Importantly, we find that upregulated p21 expression is essential for the survival of BRCA2-deficient cells and tumours. Thus, our work demonstrates that ß-catenin toxicity in cancer cells with compromised BRCA1/2 function is driven by transcriptional alterations that cause aberrant replication and inflict DNA damage.


Assuntos
Proteína BRCA1/genética , Proteína BRCA2/genética , Oncogenes/genética , Transcrição Genética/genética , beta Catenina/genética , Proteína BRCA1/deficiência , Proteína BRCA2/deficiência , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Sobrevivência Celular/genética , Células Cultivadas , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Dano ao DNA , Feminino , Perfilação da Expressão Gênica/métodos , Células HeLa , Humanos , Neoplasias Ovarianas/genética , Neoplasias Ovarianas/metabolismo , RNA-Seq/métodos , beta Catenina/metabolismo
9.
Nat Commun ; 12(1): 4841, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34404770

RESUMO

RAS proteins are GTPases that lie upstream of a signaling network impacting cell fate determination. How cells integrate RAS activity to balance proliferation and cellular senescence is still incompletely characterized. Here, we identify ZNF768 as a phosphoprotein destabilized upon RAS activation. We report that ZNF768 depletion impairs proliferation and induces senescence by modulating the expression of key cell cycle effectors and established p53 targets. ZNF768 levels decrease in response to replicative-, stress- and oncogene-induced senescence. Interestingly, ZNF768 overexpression contributes to bypass RAS-induced senescence by repressing the p53 pathway. Furthermore, we show that ZNF768 interacts with and represses p53 phosphorylation and activity. Cancer genomics and immunohistochemical analyses reveal that ZNF768 is often amplified and/or overexpressed in tumors, suggesting that cells could use ZNF768 to bypass senescence, sustain proliferation and promote malignant transformation. Thus, we identify ZNF768 as a protein linking oncogenic signaling to the control of cell fate decision and proliferation.


Assuntos
Senescência Celular/genética , Genes ras/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Carcinogênese , Ciclo Celular , Diferenciação Celular , Proliferação de Células , Transformação Celular Neoplásica , Replicação do DNA , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Genômica , Células HeLa , Humanos , Oncogenes , Fenótipo , Fosfoproteínas , Fosforilação , Repressão Psicológica , Transdução de Sinais , Proteínas ras/genética
10.
Signal Transduct Target Ther ; 6(1): 308, 2021 08 18.
Artigo em Inglês | MEDLINE | ID: mdl-34408131

RESUMO

Cytokine storm induced by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is a major pathological feature of Coronavirus Disease 2019 (COVID-19) and a crucial determinant in COVID-19 prognosis. Understanding the mechanism underlying the SARS-CoV-2-induced cytokine storm is critical for COVID-19 control. Here, we identify that SARS-CoV-2 ORF3a and host hypoxia-inducible factor-1α (HIF-1α) play key roles in the virus infection and pro-inflammatory responses. RNA sequencing shows that HIF-1α signaling, immune response, and metabolism pathways are dysregulated in COVID-19 patients. Clinical analyses indicate that HIF-1α production, inflammatory responses, and high mortalities occurr in elderly patients. HIF-1α and pro-inflammatory cytokines are elicited in patients and infected cells. Interestingly, SARS-CoV-2 ORF3a induces mitochondrial damage and Mito-ROS production to promote HIF-1α expression, which subsequently facilitates SARS-CoV-2 infection and cytokines production. Notably, HIF-1α also broadly promotes the infection of other viruses. Collectively, during SARS-CoV-2 infection, ORF3a induces HIF-1α, which in turn aggravates viral infection and inflammatory responses. Therefore, HIF-1α plays an important role in promoting SARS-CoV-2 infection and inducing pro-inflammatory responses to COVID-19.


Assuntos
COVID-19/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Mitocôndrias/metabolismo , SARS-CoV-2/metabolismo , Transdução de Sinais , Proteínas Viroporinas/metabolismo , Células A549 , Animais , Chlorocebus aethiops , Células HEK293 , Células HeLa , Humanos , Mitocôndrias/patologia , RNA-Seq , Células THP-1 , Células Vero
11.
Nat Commun ; 12(1): 4835, 2021 08 10.
Artigo em Inglês | MEDLINE | ID: mdl-34376679

RESUMO

F-ATP synthase is a leading candidate as the mitochondrial permeability transition pore (PTP) but the mechanism(s) leading to channel formation remain undefined. Here, to shed light on the structural requirements for PTP formation, we test cells ablated for g, OSCP and b subunits, and ρ0 cells lacking subunits a and A6L. Δg cells (that also lack subunit e) do not show PTP channel opening in intact cells or patch-clamped mitoplasts unless atractylate is added. Δb and ΔOSCP cells display currents insensitive to cyclosporin A but inhibited by bongkrekate, suggesting that the adenine nucleotide translocator (ANT) can contribute to channel formation in the absence of an assembled F-ATP synthase. Mitoplasts from ρ0 mitochondria display PTP currents indistinguishable from their wild-type counterparts. In this work, we show that peripheral stalk subunits are essential to turn the F-ATP synthase into the PTP and that the ANT provides mitochondria with a distinct permeability pathway.


Assuntos
Cálcio/metabolismo , Mitocôndrias/metabolismo , Poro de Transição de Permeabilidade Mitocondrial/metabolismo , ATPases Mitocondriais Próton-Translocadoras/metabolismo , Cálcio/farmacologia , Carbonil Cianeto p-Trifluormetoxifenil Hidrazona/farmacologia , Linhagem Celular Tumoral , Células HeLa , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Potencial da Membrana Mitocondrial/fisiologia , Mitocôndrias/efeitos dos fármacos , ATPases Mitocondriais Próton-Translocadoras/genética , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Ionóforos de Próton/farmacologia
12.
Anal Chem ; 93(32): 11072-11080, 2021 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-34342978

RESUMO

Pyrylium salts are considered efficient chemical tags for amino groups. However, the apparent steric selectivity of pyrylium salts limits their application in the field of chemical labeling, especially during the labeling of sterically hindered compounds like amino acids, peptides, and proteins. Herein, we have investigated the effects of the α-substitution of pyrylium salts on their reactivity. We have also investigated the mechanism of nucleophilic reactions with pyrylium salts and further proposed that the reactivity of pyrylium salts mainly depends on the position and type of their substituents. A series of pyrylium salts were synthesized, and a highly active α-monosubstituted pyrylium salt, 2,4,5-triphenylpyrylium, was developed for efficient chemical labeling. All of the 15 amino acids studied were efficiently labeled under optimized reaction conditions. The 2,4,5-triphenylpyrylium salt was highly efficient in comparison to the previously reported 2,4,6-triphenylpyrylium salt developed for lysine-specific modifications. Furthermore, we successfully used 2,4,5-triphenylpyrylium salt for the hydrophobic labeling of peptides and protein hydrolysates. The most striking observation was that the ionization efficiency of short-chain multilabeled peptides in mixed samples, after derivatization, increased by up to 60 times. The increase in ionization efficiency gradually decreased with increasing peptide chain length. During the "soft" collision-induced dissociation (CID) process, the peptide was tagged at the N-terminus with 2,4,5-triphenylpyrylium, producing abundant a-type ions and b-type ions (Δ = 28), which eases the peptide resequencing process and assists in cracking the peptide codes. Moreover, 2,4,5-triphenylpyrylium has been utilized for the proteomic analysis of HeLa cell digests. In addition, 215 additional proteins were identified in the labeled products and the coverage of most proteins was improved.


Assuntos
Peptídeos , Proteômica , Células HeLa , Humanos , Indicadores e Reagentes , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
13.
Nat Commun ; 12(1): 5057, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417449

RESUMO

Argonaute is the primary mediator of metazoan miRNA targeting (MT). Among the currently identified >1,500 human RNA-binding proteins (RBPs), there are only a handful of RBPs known to enhance MT and several others reported to suppress MT, leaving the global impact of RBPs on MT elusive. In this study, we have systematically analyzed transcriptome-wide binding sites for 150 human RBPs and evaluated the quantitative effect of individual RBPs on MT efficacy. In contrast to previous studies, we show that most RBPs significantly affect MT and that all of those MT-regulating RBPs function as MT enhancers rather than suppressors, by making the local secondary structure of the target site accessible to Argonaute. Our findings illuminate the unappreciated regulatory impact of human RBPs on MT, and as these RBPs may play key roles in the gene regulatory network governed by metazoan miRNAs, MT should be understood in the context of co-regulating RBPs.


Assuntos
MicroRNAs/metabolismo , Proteínas de Ligação a RNA/metabolismo , Regiões 3' não Traduzidas/genética , Sítios de Ligação , Evolução Molecular , Células HeLa , Células Hep G2 , Humanos , MicroRNAs/genética , Conformação de Ácido Nucleico , Ligação Proteica , RNA Mensageiro/química , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Reprodutibilidade dos Testes , Especificidade por Substrato
14.
Nucleic Acids Res ; 49(15): 8625-8641, 2021 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-34358319

RESUMO

Transcriptional regulation by Wnt signalling is primarily thought to be accomplished by a complex of ß-catenin and TCF family transcription factors (TFs). Although numerous studies have suggested that additional TFs play roles in regulating Wnt target genes, their mechanisms of action have not been investigated in detail. We characterised a Wnt-responsive element (WRE) downstream of the Wnt target gene Axin2 and found that TCFs and Caudal type homeobox (CDX) proteins were required for its activation. Using a new separation-of-function TCF mutant, we found that WRE activity requires the formation of a TCF/CDX complex. Our systematic mutagenesis of this enhancer identified other sequences essential for activation by Wnt signalling, including several copies of a novel CAG DNA motif. Computational and experimental evidence indicates that the TCF/CDX/CAG mode of regulation is prevalent in multiple WREs. Put together, our results demonstrate the complex nature of cis- and trans- interactions required for signal-dependent enhancer activity.


Assuntos
Elementos Facilitadores Genéticos , Proteínas de Homeodomínio/metabolismo , Fatores de Transcrição TCF/metabolismo , Via de Sinalização Wnt , Proteína Axina/genética , Sítios de Ligação , DNA/química , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Humanos , Motivos de Nucleotídeos , Proteínas Proto-Oncogênicas c-myc/genética , Proteína 2 Semelhante ao Fator 7 de Transcrição/metabolismo
15.
Photochem Photobiol Sci ; 20(8): 1087-1098, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34398442

RESUMO

In this study, C-doped TiO2 nanoparticles (C-TiO2) were prepared and tested as a photosensitizer for visible-light-driven photodynamic therapy against cervical cancer cells (HeLa). X-ray diffraction and Transmission Electron Microscopy confirmed the anatase form of nanoparticles, spherical shape, and size distribution from 5 to 15 nm. Ultraviolet-visible light spectroscopy showed that C doping of TiO2 enhances the optical absorption in the visible light range caused by a bandgap narrowing. The photo-cytotoxic activity of C-TiO2 was investigated in vitro against HeLa cells. The lack of dark cytotoxicity indicates good biocompatibility of C-TiO2. In contrast, a combination with blue light significantly reduced the survival of HeLa cells: illumination only decreased cell viability by 30% (15 min of illumination, 120 µW power), and 60% when HeLa cells were preincubated with C-TiO2. We have also confirmed blue light-induced C-TiO2-catalyzed generation of reactive oxygen species in vitro and intracellularly. Oxidative stress triggered by C-TiO2/blue light was the leading cause of HeLa cell death. Fluorescent labeling of treated HeLa cells showed distinct morphological changes after the C-TiO2/blue light treatment. Unlike blue light illumination, which caused the appearance of large necrotic cells with deformed nuclei, cytoplasm swelling, and membrane blebbing, a combination of C-TiO2/blue light leads to controlled cell death, thus providing a better outcome of local anticancer therapy.


Assuntos
Carbono/química , Nanopartículas , Fototerapia , Titânio/química , Titânio/farmacologia , Neoplasias do Colo do Útero/patologia , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Terapia Combinada , Feminino , Células HeLa , Humanos
16.
Anal Chem ; 93(34): 11758-11764, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34410685

RESUMO

The detection of SO2 and its derivatives is indispensable for monitoring atmospheric, water quality, and biological fluctuation of oxidative stress and metabolism of biothiols within native cellular contexts. In this article, the brush copolymer nanoreactors containing amine-terminated PDMS were used to encapsulate the fluorescent indicator C11-BDP, forming sulfite-sensitive nanoreactors (ssNRs). Surprisingly, the ssNRs were found to be highly selective to sulfite over a range of reactive oxygen/nitrogen/sulfur species and anions, which was not observed with freely dissolved indicators. The ssNRs showed a rapid response (t95 = 65 s), an excellent detection limit (0.7 µM), and a very high sensitivity (ca. 1000-fold ratiometric intensity change) to sulfite. For cellular studies, the ssNRs exhibited negligible toxicity and could be endocytosed into endosomes and lysosomes. Finally, the ssNRs allowed us to visualize the different responses of three different types of cells (pre-adipocytes, RAW264.7, and HeLa cells) to external stimuli in the culture media with sulfites and lipopolysaccharides.


Assuntos
Corantes Fluorescentes , Sulfitos , Células HeLa , Humanos , Peroxidação de Lipídeos , Nanotecnologia
17.
Anal Chem ; 93(34): 11826-11835, 2021 08 31.
Artigo em Inglês | MEDLINE | ID: mdl-34461732

RESUMO

Cancer ranks as a leading cause of death in every country of the world. However, if they are discovered early, a lot of cancers can be prevented or cured. Discovering and monitoring cancer markers are the main methods for early diagnosis of cancer. To date, many fluorescent probes designed and used for early cancer diagnosis can only react with a single marker, which always causes insufficient accuracy in complex systems. Herein, a novel near-infrared (NIR) fluorescent probe (CyO-DNP) for the sequential detection of H2S and H+ is synthesized. In this probe, a heptamethine dye is selected as the fluorophore and a 2,4-dinitrophenyl (DNP) ether is chosen as recognition group. In the presence of H2S, CyO-DNP is transformed into CyO, which exhibits an intense fluorescence at 663 nm. Then, H+ induces the protonation of CyO to obtain CyOH, and the final fluorescence emission at 793 nm significantly enhances. Owing to the low cytotoxicity and the NIR fluorescence emission, CyO-DNP can sequentially monitor endogenous H2S and H+ in cancer cells and image exogenous and endogenous H2S and H+ in mice. It is worth mentioning that CyO-DNP can effectively avoid the false positive signal caused by the liver and kidney and discriminate normal mice and tumor mice accurately. For all we know, CyO-DNP is the first fluorescent probe for early accurate diagnosis of cancer by sequentially detecting H2S and H+.


Assuntos
Sulfeto de Hidrogênio , Neoplasias , Animais , Corantes Fluorescentes , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Camundongos , Microscopia de Fluorescência , Neoplasias/diagnóstico
18.
Theranostics ; 11(16): 7767-7778, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34335963

RESUMO

Background: Lipid droplets (LDs) establish a considerable number of contact sites with mitochondria to enable energy transfer and communication. In this study, we developed a fluorescent biosensor to image LD-mitochondria interactions at the nanoscale and further explored the function of LD-mediated matrix transmission in processes involving multi-organelle interactions. Methods: A fluorescent probe called C-Py (C21H19N3O2, 7-(diethylamino) coumarin-3-vinyl-4-pyridine acetonitrile) was designed and synthesized. Colocalization of C-Py and the commercial LD stain Nile Red was analyzed in HeLa cells. The fluorescence stability and signal to background ratio of C-Py under structured illumination microscopy (SIM) were compared to those of the commercial probe BODIPY493/503. The cytotoxicity of C-Py was assessed using CCK-8 assays. The uptake pattern of C-Py in HeLa cells was then observed under various temperatures, metabolic levels, and endocytosis levels. Contact sites between LDs and various organelles, such as mitochondria, nuclei, and cell membrane, were imaged and quantitated using SIM. Physical changes to the contact sites between LDs and mitochondria were monitored after lipopolysaccharide induction. Results: A LD-targeted fluorescent biosensor, C-Py, with good specificity, low background signal, excellent photostability, low cytotoxicity, and high cellular permeability was developed for tracking LD contact sites with multiple organelles using SIM. Using C-Py, the subcellular distribution and dynamic processes of LDs in living cells were observed under SIM. The formation of contact sites between LDs and multiple organelles was visualized at a resolution below ~200 nm. The number of LD-mitochondria contact sites formed was decreased by lipopolysaccharide treatment inducing an inflammatory environment. Conclusions: C-Py provides strategies for the design of ultra-highly selective biosensors and a new tool for investigating the role and regulation of LDs in living cells at the nanoscale.


Assuntos
Gotículas Lipídicas/metabolismo , Mitocôndrias/metabolismo , Imagem Individual de Molécula/métodos , Técnicas Biossensoriais/métodos , Corantes Fluorescentes/síntese química , Corantes Fluorescentes/metabolismo , Células HeLa , Humanos , Metabolismo dos Lipídeos/fisiologia
19.
FASEB J ; 35(9): e21825, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34383978

RESUMO

Ubiquitination is an essential post-translational modification that regulates protein stability or function. Its substrate specificity is dictated by various E3 ligases. The human C-terminal to LisH (CTLH) complex is a newly discovered multi-subunit really interesting new gene (RING) E3 ligase with only a few known ubiquitination targets. Here, we used mass spectrometry-based proteomic techniques to gain insight into CTLH complex function and ubiquitination substrates in HeLa cells. First, global proteomics determined proteins that were significantly increased, and thus may be substrates targeted for degradation, in cells depleted of CTLH complex member RanBPM. RanBPM-dependent ubiquitination determined using diGLY-enriched proteomics and the endogenous RanBPM interactome further revealed candidate ubiquitination targets. Three glycolysis enzymes alpha-enolase, L-lactate dehydrogenase A chain (LDHA), and pyruvate kinase M1/2 (PKM) had decreased ubiquitin sites in shRanBPM cells and were found associated with RanBPM in the interactome. Reduced polyubiquitination was validated for PKM2 and LDHA in cells depleted of RanBPM and CTLH complex RING domain subunit RMND5A. PKM2 and LDHA protein levels were unchanged, yet their activity was increased in extracts of cells with downregulated RanBPM. Finally, RanBPM deficient cells displayed enhanced glycolysis and deregulated central carbon metabolism. Overall, this study identifies potential CTLH complex ubiquitination substrates and uncovers that the CTLH complex inhibits glycolysis via non-degradative ubiquitination of PKM2 and LDHA.


Assuntos
Glicólise/fisiologia , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitinação/fisiologia , Animais , Linhagem Celular Tumoral , Células HeLa , Humanos , L-Lactato Desidrogenase/metabolismo , Camundongos , Proteômica/métodos , Especificidade por Substrato , Ubiquitina/metabolismo
20.
Int J Mol Sci ; 22(15)2021 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-34361008

RESUMO

The emergence of multidrug-resistant (MDR) bacteria through the abuse and long-term use of antibiotics is a serious health problem worldwide. Therefore, novel antimicrobial agents that can cure an infection from MDR bacteria, especially gram-negative bacteria, are urgently needed. Antimicrobial peptides, part of the innate immunity system, have been studied to find bactericidal agents potent against MDR bacteria. However, they have many problems, such as restrained systemic activity and cytotoxicity. In a previous study, we suggested that the K58-R78 domain of Romo1, a mitochondrial protein encoded by the nucleus, was a promising treatment candidate for sepsis caused by MDR bacteria. Here, we performed sequence optimization to enhance the antimicrobial activity of this peptide and named it as AMPR-22 (antimicrobial peptide derived from Romo1). It showed broad-spectrum antimicrobial activity against 17 sepsis-causing bacteria, including MDR strains, by inducing membrane permeabilization. Moreover, treatment with AMPR-22 enabled a remarkable survival rate in mice injected with MDR bacteria in a murine model of sepsis. Based on these results, we suggest that AMPR-22 could be prescribed as a first-line therapy (prior to bacterial identification) for patients diagnosed with sepsis.


Assuntos
Proteínas de Membrana/química , Proteínas Mitocondriais/química , Fragmentos de Peptídeos/uso terapêutico , Proteínas Citotóxicas Formadoras de Poros/uso terapêutico , Sepse/tratamento farmacológico , Animais , Células Cultivadas , Farmacorresistência Bacteriana , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Células HEK293 , Células HeLa , Humanos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Proteínas Citotóxicas Formadoras de Poros/química , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Domínios Proteicos , Sepse/microbiologia
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