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1.
Proc Natl Acad Sci U S A ; 120(42): e2302780120, 2023 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-37812701

RESUMO

Brain L-serine is critical for neurodevelopment and is thought to be synthesized solely from glucose. In contrast, we found that the influx of L-serine across the blood-brain barrier (BBB) is essential for brain development. We identified the endothelial Slc38a5, previously thought to be a glutamine transporter, as an L-serine transporter expressed at the BBB in early postnatal life. Young Slc38a5 knockout (KO) mice exhibit developmental alterations and a decrease in brain L-serine and D-serine, without changes in serum or liver amino acids. Slc38a5-KO brains exhibit accumulation of neurotoxic deoxysphingolipids, synaptic and mitochondrial abnormalities, and decreased neurogenesis at the dentate gyrus. Slc38a5-KO pups exhibit motor impairments that are affected by the administration of L-serine at concentrations that replenish the serine pool in the brain. Our results highlight a critical role of Slc38a5 in supplying L-serine via the BBB for proper brain development.


Assuntos
Barreira Hematoencefálica , Encéfalo , Camundongos , Animais , Barreira Hematoencefálica/metabolismo , Encéfalo/metabolismo , Transporte Biológico , Transporte de Íons , Serina/metabolismo , Camundongos Knockout
2.
Semin Cell Dev Biol ; 103: 14-19, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32081627

RESUMO

The islet of Langerhans contains at least five types of endocrine cells producing distinct hormones. In response to nutrient or neuronal stimulation, islet endocrine cells release biochemicals including peptide hormones to regulate metabolism and to control glucose homeostasis. It is now recognized that malfunction of islet cells, notably insufficient insulin release of ß-cells and hypersecretion of glucagon from α-cells, represents a causal event leading to hyperglycemia and frank diabetes, a disease that is increasing at an alarming rate to reach an epidemic level worldwide. Understanding the mechanisms regulating stimulus-secretion coupling and investigating how islet ß-cells maintain a robust secretory activity are important topics in islet biology and diabetes research. To facilitate such studies, a number of biological systems and assay platforms have been developed for the functional analysis of islet cells. These technologies have enabled detailed analyses of individual islets at the cellular level, either in vitro, in situ, or in vivo.


Assuntos
Diabetes Mellitus/metabolismo , Técnicas In Vitro/métodos , Dosimetria in Vivo/métodos , Ilhotas Pancreáticas/metabolismo , Humanos
3.
Molecules ; 27(18)2022 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-36144859

RESUMO

Ceramides belong to the sphingolipid family and represent the central hub of the sphingolipid network. In obesity, oversupply of saturated fatty acids including palmitate raises ceramide levels which can be detrimental to cells. Elevated ceramides can cause insulin resistance, endoplasmic reticulum stress, and mitochondrial dysfunction. Studies over the last few decades have highlighted the role played by ceramides in pancreatic islet ß-cell apoptosis, especially under glucolipotoxic and inflammatory conditions. This review focuses on ceramides and adiponectin receptor signaling, summarizing recent advancements in our understanding of their roles in islet ß-cells and the discovery of zinc-dependent lipid hydrolase (ceramidase) activity of adiponectin receptors. The therapeutic potential of targeting these events to prevent islet ß-cell loss for treating diabetes is discussed.


Assuntos
Ceramidas , Diabetes Mellitus , Apoptose/fisiologia , Ceramidases , Ácidos Graxos , Humanos , Palmitatos , Receptores de Adiponectina , Esfingolipídeos , Zinco
4.
J Lipid Res ; 62: 100095, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34214600

RESUMO

The pleiotropic actions of adiponectin in improving cell survival and metabolism have motivated the development of small-molecule therapeutic agents for treating diabetes and lipotoxicity. AdipoRon is a synthetic agonist of the adiponectin receptors, yet is limited by its poor solubility and bioavailability. In this work, we expand on the protective effects of AdipoRon in pancreatic ß-cells and examine how structural modifications could affect the activity, pharmacokinetics, and bioavailability of this small molecule. We describe a series of AdipoRon analogs containing amphiphilic ethylene glycol (PEG) chains. Among these, AdipoRonPEG5 induced pleiotropic effects in mice under insulinopenic and high-fat diet (HFD) conditions. While both AdipoRon and AdipoRonPEG5 substantially attenuate palmitate-induced lipotoxicity in INS-1 cells, only AdipoRonPEG5 treatment is accompanied by a significant reduction in cytotoxic ceramides. In vivo, AdipoRonPEG5 can substantially reduce pancreatic, hepatic, and serum ceramide species, with a concomitant increase in the corresponding sphingoid bases and improves insulin sensitivity of mice under HFD feeding conditions. Furthermore, hyperglycemia in streptozotocin (STZ)-induced insulinopenic adiponectin-null mice is also attenuated upon AdipoRonPEG5 treatment. Our results suggest that AdipoRonPEG5 is more effective in reducing ceramides and dihydroceramides in the liver of HFD-fed mice than AdipoRon, consistent with its potent activity in activating ceramidase in vitro in INS-1 cells. Additionally, these results indicate that the beneficial effects of AdipoRonPEG5 can be partially attributed to improved pharmacokinetics as compared with AdipoRon, thus suggesting that further derivatization may improve affinity and tissue-specific targeting.


Assuntos
Dieta Hiperlipídica/efeitos adversos , Glucose/metabolismo , Metabolismo dos Lipídeos/efeitos dos fármacos , Piperidinas/farmacologia , Animais , Resistência à Insulina , Fígado/química , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Piperidinas/administração & dosagem , Piperidinas/química , Polietilenoglicóis/química
5.
Zhongguo Zhong Yao Za Zhi ; 46(5): 1293-1300, 2021 Mar.
Artigo em Zh | MEDLINE | ID: mdl-33787125

RESUMO

The innovation and patent layout of traditional Chinese medicine compounds reflects the innovation level of the traditio-nal Chinese medicine industry to a certain extent. Lianhua Qingwen Formula was taken as an example to analyze the innovation and patent layout of traditional Chinese medicine compounds. The study first proposed an innovative technology system for traditional Chinese medicine compounds, and then analyzed the advantages and disadvantages of Lianhua Qingwen Formula in innovation and patent layout based on 56 patents and other relevant patents. The analysis results showed that Lianhua Qingwen Formula had the following characte-ristics in terms of patent layout. In terms of innovation technical route, the patented technical route of Lianhua Qingwen Formula was mainly based on the composition and preparation of granules as the first choice, followed by corresponding process improvements, new uses, and detection methods as the main improvement routes. In terms of the corresponding patent layout, the basic patent protection scope of Lianhua Qingwen Formula completely covered marketed drugs, and then took new functions as the main layout strategy for subsequent patent applications. With the advancement of modern technical means, the preparation process and testing methods have been optimized continuously. At the same time, the international patent layout was given the priority in domestic patent application. Based on the above characteristics, the study gave suggestions for follow-up innovation and patent work for Lianhua Qingwen Formula, so as to provide enlightenment for other traditional Chinese medicine companies in exploring original innovation of traditional Chinese medicine compounds, improving innovative methods, and enhancing the ability of patent layout of innovative achievements.


Assuntos
Medicamentos de Ervas Chinesas , Medicina Tradicional Chinesa , Projetos de Pesquisa , Tecnologia
6.
Plant Dis ; 2020 Nov 02.
Artigo em Inglês | MEDLINE | ID: mdl-33135988

RESUMO

Tobacco (Nicotiana tabacum L.) is one of the most important cash crops in China. In June 2019, tobacco (cv. Yunyan 87) samples with gray spots surrounded by yellowish ring were collected in Zhengan (107.43° N, 28.55° E), Guizhou province, China. Pieces of leaf tissue (3 mm × 3 mm) that were cut at the junction of diseased and healthy portion were surface sterilized and plated on potato dextrose agar (PDA). After incubation at 25°C in the dark for 7 days, an isolate (T22) was chosen and used for pathogen identification. The colonies had aerial hyphae, initially white and then turned grey, and produced a soluble red pigmen on PDA. The colonies were floccose aerial mycelia, dark grey, with pale brown hyphae, and produced conidia on oatmeal agar. Conidia were ovoid or ampulliform, black, smooth. Based on morphological characteristics, isolate T22 was identified as Nigrospora aurantiaca (Wang et al. 2017). For molecular identification, the large subunit (LSU) and internal transcribed spacer (ITS) of ribosomal RNA, ß-tubulin (TUB) and translation elongation factor 1-alpha (TEF1) genes of T22 were amplified by PCR with the primer sets LROR/LR5, ITS1/ITS4, Bt2a/Bt2b and EF1-728F/EF2 (Suwannarach et al.2019), then PCR products were sequenced. Their GenBank accession numbers were MT341787, MT328649, MT348395 and MT348394, respectively. Phylogenetic tree of combined LSU, ITS, TUB, and TEF sequences showed that isolate T22 was assigned to N. aurantiaca strain (CGMCC 3.18130 and LC 7034) with 100% bootstrap support. Based on morphological characteristics and multi-gene molecular analysis, isolate T22 was identified as N. aurantiaca. To fulfill Koch's postulates, PDA plugs grown with N. aurantiaca were placed on the leaves of four tobacco plants (cv. Yunyan 87) at the 10-leaf stage. Leaves inoculated with PDA only plugs served as the controls. Treated plants were maintained in a greenhouse with temperatures ranging from 18 to 28 °C. Five days after inoculation, typical symptoms were observed on inoculated leaves but not on the controls. N. aurantiaca was re-isolated from the diseased leaves but not from the controls. To our best of knowledge, this is the first report of N. aurantiaca causing leaf spot on tobacco in China. N. aurantiaca has been reported to cause leaf spot on Castanea mollissima in China (Luo et al. 2020). Due to potential serious damage caused by the disease in this region, proper disease management practices should be developed and implemented.

7.
Proc Natl Acad Sci U S A ; 113(37): E5464-71, 2016 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-27562169

RESUMO

Many secretory tissues release Zn(II) ions along with other molecules in response to external stimuli. Here we demonstrate that secretion of Zn(II) ions from normal, healthy prostate tissue is stimulated by glucose in fasted mice and that release of Zn(II) can be monitored by MRI. An ∼50% increase in water proton signal enhancement is observed in T1-weighted images of the healthy mouse prostate after infusion of a Gd-based Zn(II) sensor and an i.p. bolus of glucose. Release of Zn(II) from intracellular stores was validated in human epithelial prostate cells in vitro and in surgically exposed prostate tissue in vivo using a Zn(II)-sensitive fluorescent probe known to bind to the extracellular surface of cells. Given the known differences in intracellular Zn(II) stores in healthy versus malignant prostate tissues, the Zn(II) sensor was then evaluated in a transgenic adenocarcinoma of the mouse prostate (TRAMP) model in vivo. The agent proved successful in detecting small malignant lesions as early as 11 wk of age, making this noninvasive MR imaging method potentially useful for identifying prostate cancer in situations where it may be difficult to detect using current multiparametric MRI protocols.


Assuntos
Meios de Contraste/administração & dosagem , Imageamento por Ressonância Magnética/métodos , Neoplasias da Próstata/diagnóstico por imagem , Zinco/metabolismo , Animais , Modelos Animais de Doenças , Corantes Fluorescentes , Humanos , Masculino , Camundongos , Próstata/diagnóstico por imagem , Próstata/metabolismo , Neoplasias da Próstata/metabolismo , Neoplasias da Próstata/patologia , Zinco/química
8.
RNA Biol ; 14(2): 259-274, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27982722

RESUMO

MicroRNAs are small non-coding RNAs acting as posttranscriptional repressors of gene expression. Identifying mRNA targets of a given miRNA remains an outstanding challenge in the field. We have developed a new experimental approach, TargetLink, that applied locked nucleic acid (LNA) as the affinity probe to enrich target genes of a specific microRNA in intact cells. TargetLink also consists a rigorous and systematic data analysis pipeline to identify target genes by comparing LNA-enriched sequences between experimental and control samples. Using miR-21 as a test microRNA, we identified 12 target genes of miR-21 in a human colorectal cancer cell by this approach. The majority of the identified targets interacted with miR-21 via imperfect seed pairing. Target validation confirmed that miR-21 repressed the expression of the identified targets. The cellular abundance of the identified miR-21 target transcripts varied over a wide range, with some targets expressed at a rather low level, confirming that both abundant and rare transcripts are susceptible to regulation by microRNAs, and that TargetLink is an efficient approach for identifying the target set of a specific microRNA in intact cells. C20orf111, one of the novel targets identified by TargetLink, was found to reside in the nuclear speckle and to be reliably repressed by miR-21 through the interaction at its coding sequence.


Assuntos
Perfilação da Expressão Gênica , MicroRNAs/genética , Oligonucleotídeos/genética , Interferência de RNA , RNA Mensageiro/genética , Pareamento de Bases , Sequência de Bases , Linhagem Celular , Expressão Gênica , Técnicas de Inativação de Genes , Genes Reporter , Sequenciamento de Nucleotídeos em Larga Escala , Humanos
9.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(4): 1001-6, 2016 Apr.
Artigo em Zh | MEDLINE | ID: mdl-30048097

RESUMO

Photovoltaic power generation is one of the best ways to utilize solar energy, but the cost of electricity is very high. To reduce the cost of photovoltaic power generation, in this paper, a type of planar luminescent solar concentrator waveguides based on Lumogen F Red 305 (LR305) dye with each size of 50 mm×50 mm×5 mm was proposed with radical polymerization method. The optical properties and photo-electricity outputs of the waveguides were characterized.

10.
Guang Pu Xue Yu Guang Pu Fen Xi ; 36(4): 1007-12, 2016 Apr.
Artigo em Zh | MEDLINE | ID: mdl-30048098

RESUMO

Flavanone derivatives are important active ingredients of natural medicine, so the synthesis of these compounds is one of the research hotspots of organic synthesis. Nevertheless, there is little research on fluorescence properties of these compounds up to now. Fluorescence properties of flavanone and 6 kinds of hydroxyl derivatives are studied in this paper. It is found that aqueous solutions of flavanone (FV), 7-hydroxyflavanone (7HF) and 6-hydroxyflavanone (6HF) have fluorescence, but aqueous solutions of 2'-hydroxyflavanone (2'HF), 4'-hydroxyflavanone (4'HF), naringenin and pinocembrin basically have no fluorescence. In three dimensional fluorescence spectra, excitation wavelengths λex of FV are located at 235, 265 and 340 nm, emission wavelength λem is at 386 nm; λex of 7HF are at 230, 276 and 315 nm, λem is at 391 nm; λex of 6HF are at 260 and 356 nm, em is at 482 nm. Influences of pH on fluorescence of FV, 7HF and 6HF are studied, and the reasons of pH affects on fluorescence are discussed from the viewpoint of molecular structure. The UV-absorption spectra of 7HF and 6HF at different pH are studied, and the proton ionization constants (pKa) of 7HF and 6HF are determined respectively to be 7.26±0.05 and 9.90±0.02, by a pH-absorption method. Influences of solvent (methanol) on fluorescence of FV, 7HF and 6HF are studied, and find that the fluorescence of FV and 7HF in methanol are weaker than that in water, but the fluorescence of 6HF in methanol is much stronger. In ordered media (SDS, CTAB and ß-CD), fluorescence of FV and 7HF decreased than that in water, but the fluorescence of 6HF enhanced in the media of ß-CD or CTAB. Using quinine sulfate or L-tryptophane as reference, fluorescence quantum yields of FV and 7HF aqueous solutions are measured to be 0.057 and 0.012, respectively; fluorescence quantum yields of 6HF in methanol or in aqueous solution containing 1.62 mg·mL-1 ß-CD are measured to be 0.064 or 0.012, respectively.

11.
Development ; 139(22): 4191-201, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23093425

RESUMO

The C. elegans left and right AWC olfactory neurons specify asymmetric subtypes, one default AWC(OFF) and one induced AWC(ON), through a stochastic, coordinated cell signaling event. Intercellular communication between AWCs and non-AWC neurons via a NSY-5 gap junction network coordinates AWC asymmetry. However, the nature of intercellular signaling across the network and how individual non-AWC cells in the network influence AWC asymmetry is not known. Here, we demonstrate that intercellular calcium signaling through the NSY-5 gap junction neural network coordinates a precise 1AWC(ON)/1AWC(OFF) decision. We show that NSY-5 gap junctions in C. elegans cells mediate small molecule passage. We expressed vertebrate calcium-buffer proteins in groups of cells in the network to reduce intracellular calcium levels, thereby disrupting intercellular communication. We find that calcium in non-AWC cells of the network promotes the AWC(ON) fate, in contrast to the autonomous role of calcium in AWCs to promote the AWC(OFF) fate. In addition, calcium in specific non-AWCs promotes AWC(ON) side biases through NSY-5 gap junctions. Our results suggest a novel model in which calcium has dual roles within the NSY-5 network: autonomously promoting AWC(OFF) and non-autonomously promoting AWC(ON).


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/citologia , Caenorhabditis elegans/metabolismo , Sinalização do Cálcio , Conexinas/metabolismo , Junções Comunicantes/metabolismo , Neurônios/citologia , Neurônios Receptores Olfatórios/metabolismo , Animais , Transporte Biológico , Caenorhabditis elegans/genética , Calbindinas , Cálcio/metabolismo , Comunicação Celular , Células Cultivadas , Regulação da Expressão Gênica no Desenvolvimento , Canais Iônicos/metabolismo , Proteínas de Membrana/metabolismo , Neurônios/metabolismo , Condutos Olfatórios , Neurônios Receptores Olfatórios/citologia , Proteína G de Ligação ao Cálcio S100/metabolismo , Transdução de Sinais
12.
Bioconjug Chem ; 26(8): 1443-50, 2015 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-26121325

RESUMO

The pancreatic islet beta cell plays an essential role in maintaining the normal blood glucose level by releasing insulin. Loss of functional beta cell mass leads to diabetes­a disease affecting ∼9% of the population worldwide. There has been great interest and intense effort in developing imaging probes for monitoring islet beta cells, and glucagon-like peptide-1 receptor (GLP-1R) has emerged as a valuable biomarker for targeting beta cells. However, efforts thus far in GLP-1R mediated beta cell labeling and imaging has largely, if not exclusively, focused on developing imaging probes for monitoring beta cell mass, and few studies have investigated imaging beta cell function (insulin release) through GLP-1R. We now report the design and synthesis of a bioconjugate, ZIMIR-Ex4(9-39), that consists of a fluorescent Zn(2+) sensor and a truncated exendin 4 peptide for imaging insulin/Zn(2+) release in islet beta cells. In vitro, the conjugate bound to Zn(2+) with high affinity and displayed a robust fluorescence enhancement upon Zn(2+) chelation. When added to beta cells at submicromolar concentration, ZIMIR-Ex4(9-39) rapidly labeled cell surface in minutes to report the dynamics of insulin/Zn(2+) release with high spatiotemporal resolution. Future explorations of this approach may lead to probes for tracking beta cell function using different imaging modalities.


Assuntos
Exocitose/fisiologia , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Células Secretoras de Insulina/citologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Imagem Molecular/métodos , Zinco/metabolismo , Animais , Técnicas Biossensoriais/métodos , Células Cultivadas , Corantes Fluorescentes/química , Secreção de Insulina , Camundongos , Microscopia de Fluorescência , Células NIH 3T3
13.
Yao Xue Xue Bao ; 50(10): 1324-9, 2015 Oct.
Artigo em Zh | MEDLINE | ID: mdl-26837181

RESUMO

Fluorescence enhancement reaction of flavoxate hydrochloride (FX) in strong alkali solution was studied, the mechanism of the reaction was investigated, and a novel fluorimetric method for analysis of FX in drug sample was established. FX has no intrinsic fluorescence, but it can slowly produce fluorescence in strong alkali solution. Heating can promote the fluorescence enhancement reaction. In 3D fluorescence spectra of the decomposition product of FX, two fluorescence peaks, located respectively at excitation wavelengths λex/ emission wavelength λem =223/410 nm, and 302/410 nm, were observed. Using quinine sulfate as a reference, fluorescence quantum yield of the decomposition product was measured to be 0.50. The structural characteriza- tion and spectral analysis of the decomposition product reveal that ester bond hydrolysis reaction of FX is firstly occurred during heating process, forming 3-methylflavone-8-carboxylic acid (MFA), then a cleavage reaction of the γ-pyrone ring of MFA occurred, producing α, ß-unsaturated ketone. This product includes adjacent hydroxyl benzoic acid group in its molecule, which can form intramolecular hydrogen bond under alkaline condition, so that increase the conjugate degree and enhance the rigidity of the molecule, and thereby cause fluorescence enhancement. Based on this fluorescence enhancement reaction, a fluorimetric method was proposed for the determination of FX. A linear calibration curve covered the concentration range 0.020 3-0.487 µg · mL. The regression equation was I(F) = 23.9 + 5357.3 c, with correlation coefficient r = 0.999 7 (n = 8), detection limit D = 1.1 ng · mL(-1). The method was applied to the analysis of FX tablets, with a spiked recovery rate of 100.2%. The reliability of the method was verified by a UV-spectrophotometric method.


Assuntos
Flavoxato/química , Fluorescência , Álcalis , Calibragem , Química Farmacêutica , Flavoxato/análogos & derivados , Limite de Detecção , Reprodutibilidade dos Testes , Soluções , Comprimidos
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(3): 787-90, 2015 Mar.
Artigo em Zh | MEDLINE | ID: mdl-26117898

RESUMO

Laser induced breakdown spectroscopy (LIBS) is a widely used material element detection technology. Because of its detection result is affected by many factors, and therefore, analysing and comparising the different experimental conditions have important significance for LIBS. Experimental sample produced by Beichuan County, Sichuan Province, China, which is ordinary Portland cement P. O42.5, using eight-channel fiber optic spectrometer AvaSpec-2048-USB2-RM, delay trigger DG645 for LIBS testing. Several metallic elements as Mg, Al, Na, K, which affect cement's technical indicators were analyzed. Mainly compares the effect of laser frequency, the same point measurement times on different metal element spectral signal intensity, the optimum experimental parameters under the condition of this experiment: 10 Hz was the best laser frequency. When laser frequency is 10 Hz, the spectrum intensity of elements Mg, Al, Na, K were increased by 67.66%, 47.88%, 84.59%, 43.36% than 8 Hz. Because the tablet samples in place, the surface will have a small amount of oxidation and deliquescence, in order to measure 10 times for an average income results were recorded under the condition, with third, four records of results for the best.

15.
Cancer Sci ; 105(6): 660-6, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24673742

RESUMO

Metastasis is the leading cause of cancer-related death in almost all types of cancers, including colorectal cancer (CRC). Metastasis is a complex, multistep, dynamic biological event, and epithelial-mesenchymal transition (EMT) is a critical process during the cascade. Ajuba family proteins are LIM domain-containing proteins and are reported to be transcription repressors regulating different kinds of physiological processes. However, the expression and pathological roles of Ajuba family proteins in tumors, especial in tumor metastasis, remain poorly studied. Here, we found that JUB, but not the other Ajuba family proteins, was highly upregulated in clinical specimens and CRC cell lines. Ectopic expression of JUB induced EMT and enhanced motility and invasiveness in CRC, and vice versa. Mechanistic study revealed that JUB induces EMT via Snail and JUB is also required for Snail-induced EMT. The expression of JUB shows an inverse correlation with E-cadherin expression in clinical specimens. Taken together, these findings revealed that the LIM protein JUB serves as a tumor-promoting gene in CRC by promoting EMT, a critical process of metastasis. Thus, the LIM protein JUB may provide a novel target for therapy of metastatic CRC.


Assuntos
Neoplasias Colorretais/patologia , Transição Epitelial-Mesenquimal , Proteínas com Domínio LIM/metabolismo , Células CACO-2 , Caderinas/biossíntese , Movimento Celular , Neoplasias Colorretais/genética , Células HCT116 , Humanos , Proteínas com Domínio LIM/genética , Invasividade Neoplásica , Metástase Neoplásica , Interferência de RNA , RNA Interferente Pequeno , Transdução de Sinais , Fatores de Transcrição da Família Snail , Esferoides Celulares/patologia , Fatores de Transcrição/metabolismo , Células Tumorais Cultivadas , Regulação para Cima
16.
Proc Natl Acad Sci U S A ; 108(52): 21063-8, 2011 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-22160693

RESUMO

Current methods of monitoring insulin secretion lack the required spatial and temporal resolution to adequately map the dynamics of exocytosis of native insulin granules in intact cell populations in three dimensions. Exploiting the fact that insulin granules contain a high level of Zn(2+), and that Zn(2+) is coreleased with insulin during secretion, we have developed a fluorescent, cell surface-targeted zinc indicator for monitoring induced exocytotic release (ZIMIR). ZIMIR displayed a robust fluorescence enhancement on Zn(2+) chelation and bound Zn(2+) with high selectivity against Ca(2+) and Mg(2+). When added to cultured ß cells or intact pancreatic islets at low micromolar concentrations, ZIMIR labeled cells rapidly, noninvasively, and stably, and it reliably reported changes in Zn(2+) concentration near the sites of granule fusion with high sensitivity that correlated well with membrane capacitance measurement. Fluorescence imaging of ZIMIR-labeled ß cells followed the dynamics of exocytotic activity at subcellular resolution, even when using simple epifluorescence microscopy, and located the chief sites of insulin release to intercellular junctions. Moreover, ZIMIR imaging of intact rat islets revealed that Zn(2+)/insulin release occurred largely in small groups of adjacent ß cells, with each forming a "secretory unit." Concurrent imaging of ZIMIR and Fura-2 showed that the amplitude of cytosolic Ca(2+) elevation did not necessarily correlate with insulin secretion activity, suggesting that events downstream of Ca(2+) signaling underlie the cell-cell heterogeneity in insulin release. In addition to studying stimulation-secretion coupling in cells with Zn(2+)-containing granules, ZIMIR may find applications in ß-cell engineering and screening for molecules regulating insulin secretion on high-throughput platforms.


Assuntos
Exocitose/fisiologia , Células Secretoras de Insulina/metabolismo , Insulina/metabolismo , Imagem Molecular/métodos , Zinco/química , Animais , Linhagem Celular , Células Cultivadas , Eletrofisiologia , Humanos , Imuno-Histoquímica , Indicadores e Reagentes/química , Secreção de Insulina , Camundongos , Microscopia de Fluorescência/métodos , Estrutura Molecular , Ratos
17.
Nat Commun ; 15(1): 334, 2024 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-38184650

RESUMO

Pancreatic ß-cells respond to metabolic stress by upregulating insulin secretion, however the underlying mechanisms remain unclear. Here we show, in ß-cells from overweight humans without diabetes and mice fed a high-fat diet for 2 days, insulin exocytosis and secretion are enhanced without increased Ca2+ influx. RNA-seq of sorted ß-cells suggests altered metabolic pathways early following high fat diet, where we find increased basal oxygen consumption and proton leak, but a more reduced cytosolic redox state. Increased ß-cell exocytosis after 2-day high fat diet is dependent on this reduced intracellular redox state and requires the sentrin-specific SUMO-protease-1. Mice with either pancreas- or ß-cell-specific deletion of this fail to up-regulate exocytosis and become rapidly glucose intolerant after 2-day high fat diet. Mechanistically, redox-sensing by the SUMO-protease requires a thiol group at C535 which together with Zn+-binding suppresses basal protease activity and unrestrained ß-cell exocytosis, and increases enzyme sensitivity to regulation by redox signals.


Assuntos
Dieta Hiperlipídica , Exocitose , Animais , Humanos , Camundongos , Cisteína Endopeptidases/genética , Citosol , Dieta Hiperlipídica/efeitos adversos , Glucose , Peptídeo Hidrolases
18.
BMC Cancer ; 13: 412, 2013 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-24006921

RESUMO

BACKGROUND: Colorectal cancer (CRC) is one of the most common cancers worldwide and a leading cause of cancer related death. Although the mortality rate of CRC is decreasing, finding novel targets for its therapy remains urgent. Carboxypeptidase E (CPE), a member of the pro-protein convertases, which are involved in the maturation of protein precursors, has recently been reported as elevated in many types of cancer. However, its role and mechanisms in tumor progression are poorly understood. METHODS: In the present study, we investigated expression of CPE in CRC cell lines and tumor tissues using Western blot and real-time qRT-PCR. Plasmids for overexpression and depletion of CPE were constructed and analyzed by Western blot, MTT and colony formation assays and bromodeoxyuridine incorporation assays. The relative expression of p21, p27, and cyclin D1 were analyzed by Real-time qRT-PCR in the indicated cells. RESULTS: Our study showed that CPE was significantly upregulated in CRC cell lines and tumor tissues. MTT and colony formation assays indicated that overexpression of CPE enhanced cell growth rates. BrdU incorporation and flow-cytometry assays showed that ectopic expression of CPE increased the S-phase fraction cells. Soft agar assay proved enhanced tumorigenicity activity in CPE over-expressing CRC cells. Further studies of the molecular mechanisms of CPE indicated that is promoted cell proliferation and tumorigenicity through downregulation of p21 and p27, and upregulation of cyclin D1. CONCLUSIONS: Taken together, these data suggest that CPE plays an important role in cell cycle regulation and tumorigenicity, and may serve as a potential target for CRC therapeutics.


Assuntos
Carboxipeptidase H/genética , Transformação Celular Neoplásica/genética , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Regulação Neoplásica da Expressão Gênica , Carboxipeptidase H/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Ciclina D1/genética , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p21/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/genética , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Fase S/genética , Regulação para Cima
19.
Water Sci Technol ; 67(2): 284-92, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23168625

RESUMO

Sludge-based activated carbon (SAC) was prepared from paper mill sewage sludge by physical activation with steam for wastewater treatment in this study. The effects of preparation variables, including carbonization temperature, carbonization time, activation temperature and activation time, on iodine number and yield were investigated through orthogonal experiments. The influences of washing by deionized water and acid on the characteristics and adsorption capacities of SAC for phosphate, methylene blue and reactive red 24 were also studied. The results indicated that the optimal preparation conditions were: carbonization temperature of 350 °C, carbonization time of 40 min, activation temperature of 800 °C and activation time of 20 min. The characteristics and adsorption capacities of SAC were obviously different before and after washing, especially by acid. The surface area was improved and adsorption capacities for dyes increased after washing, while adsorption capacity for phosphate decreased. The maximum adsorption capacities provided strong evidence of the potential of SAC as an alternative adsorbent for wastewater treatment.


Assuntos
Carvão Vegetal/química , Resíduos Industriais/análise , Papel , Esgotos/química , Adsorção , China , Azul de Metileno/isolamento & purificação , Nitrogênio/isolamento & purificação , Fosfatos/isolamento & purificação , Porosidade , Temperatura , Triazinas/isolamento & purificação
20.
Mol Nutr Food Res ; 67(13): e2300033, 2023 07.
Artigo em Inglês | MEDLINE | ID: mdl-37128748

RESUMO

SCOPE: Skeletal muscle atrophy is a critical feature of cancer-associated cachexia (CAC) and it is responsible for poor quality of life and high mortality in cancer patients. The previous study demonstrates that eicosapentaenoic acid-enriched phospholipids (EPA-PL) prevent body weight loss in a mouse model of CAC. However, the role of EPA-PL on cancer-induced skeletal muscle atrophy remains unclear. METHODS AND RESULTS: In the present study, a Lewis lung carcinoma (LLC) mouse model is established, then the effect and underlying mechanism of EPA-PL on skeletal muscle atrophy in LLC-bearing mice are investigated. The results reveal that EPA-PL treatment significantly attenuates skeletal muscle atrophy in LLC-bearing mice, as evidenced by suppressing the reductions of skeletal muscle mass, myofiber cross-sectional area, and grip strength. Besides, the study finds that EPA-PL alleviated cancer-induced skeletal muscle atrophy via balancing muscle protein degradation and synthesis, inhibiting type I oxidative muscle fibers atrophy, and promoting mitochondrial function. Furthermore, the results also indicate that EPA-PL may counteract skeletal muscle atrophy in LLC mouse model via a sirtuin 1-dependent mechanism. CONCLUSION: These findings provide evidence that EPA-PL may be beneficial as a nutritional supplement for prevention and treatment of cancer-induced skeletal muscle atrophy.


Assuntos
Carcinoma Pulmonar de Lewis , Camundongos , Animais , Carcinoma Pulmonar de Lewis/complicações , Carcinoma Pulmonar de Lewis/tratamento farmacológico , Carcinoma Pulmonar de Lewis/metabolismo , Ácido Eicosapentaenoico/farmacologia , Ácido Eicosapentaenoico/metabolismo , Fosfolipídeos/metabolismo , Qualidade de Vida , Atrofia Muscular/tratamento farmacológico , Atrofia Muscular/etiologia , Atrofia Muscular/prevenção & controle , Caquexia/tratamento farmacológico , Caquexia/etiologia , Caquexia/prevenção & controle , Modelos Animais de Doenças , Músculo Esquelético/metabolismo
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