Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Sci Adv ; 10(18): eadl6409, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38701215

RESUMO

Ultrafast photoinduced melting provides an essential platform for studying nonequilibrium phase transitions by linking the kinetics of electron dynamics to ionic motions. Knowledge of dynamic balance in their energetics is essential to understanding how the ionic reaction is influenced by femtosecond photoexcited electrons with notable time lag depending on reaction mechanisms. Here, by directly imaging fluctuating density distributions and evaluating the ionic pressure and Gibbs free energy from two-temperature molecular dynamics that verified experimental results, we uncovered that transient ionic pressure, triggered by photoexcited electrons, controls the overall melting kinetics. In particular, ultrafast nonequilibrium melting can be described by the reverse nucleation process with voids as nucleation seeds. The strongly driven solid-to-liquid transition of metallic gold is successfully explained by void nucleation facilitated by photoexcited electron-initiated ionic pressure, establishing a solid knowledge base for understanding ultrafast nonequilibrium kinetics.

2.
Sensors (Basel) ; 24(7)2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38610590

RESUMO

Indoor fires may cause casualties and property damage, so it is important to develop a system that predicts fires in advance. There have been studies to predict potential fires using sensor values, and they mostly exploited machine learning models or recurrent neural networks. In this paper, we propose a stack of Transformer encoders for fire prediction using multiple sensors. Our model takes the time-series values collected from the sensors as input, and predicts the potential fire based on the sequential patterns underlying the time-series data. We compared our model with traditional machine learning models and recurrent neural networks on two datasets. For a simple dataset, we found that the machine learning models are better than ours, whereas our model gave better performance for a complex dataset. This implies that our model has a greater potential for real-world applications that probably have complex patterns and scenarios.

3.
J Synchrotron Radiat ; 31(Pt 3): 469-477, 2024 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-38517754

RESUMO

Various X-ray techniques are employed to investigate specimens in diverse fields. Generally, scattering and absorption/emission processes occur due to the interaction of X-rays with matter. The output signals from these processes contain structural information and the electronic structure of specimens, respectively. The combination of complementary X-ray techniques improves the understanding of complex systems holistically. In this context, we introduce a multiplex imaging instrument that can collect small-/wide-angle X-ray diffraction and X-ray emission spectra simultaneously to investigate morphological information with nanoscale resolution, crystal arrangement at the atomic scale and the electronic structure of specimens.

4.
Biomacromolecules ; 25(4): 2597-2606, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38483111

RESUMO

The development of highly effective hemostatic materials with high biocompatibility and outstanding performance is vital to the field of biomaterials. In this study, we develop a hemostatic fiber material that exhibits high biocompatibility and excellent performance. By incorporating polydopamine (PDA) into the alkaline treatment of silk fibroin (SF), we achieve PDA-coated SF fibers with lengths that can be controlled by the alkaline concentration. The PDA coating significantly enhances the hemostatic ability of the silk fibers and exhibits superior performance in both in vitro and ex vivo experiments. By performing animal studies involving a mouse liver puncture model and a femoral vein incision model, we demonstrate the remarkable hemostatic capability of the PDA-coated SF fibers, as evidenced by the lower blood loss compared to that of a commercial hemostat powder. These findings highlight the potential of applying a PDA-assisted alkaline treatment to SF fibers to efficiently create hemostatic fibers with controllable lengths, which would be promising candidates for clinical hemostatic applications.


Assuntos
Fibroínas , Hemostáticos , Indóis , Camundongos , Animais , Seda , Hemostáticos/farmacologia , Polímeros/farmacologia , Materiais Biocompatíveis , Fibroínas/farmacologia
5.
ACS Nano ; 17(22): 22488-22498, 2023 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-37851941

RESUMO

Mesoporous nanoparticles provide rich platforms to devise functional materials by customizing the three-dimensional (3D) structures of nanopores. With the pore network as a key tuning parameter, the noninvasive and quantitative characterization of these 3D structures is crucial for the rational design of functional materials. This has prompted researchers to develop versatile nanoprobes with a high penetration power to inspect various specimens sized a few micrometers at nanoscale 3D resolutions. Here, with adaptive phase retrievals on independent data sets with different sampling frequencies, we introduce multidistance coherent X-ray tomography as a noninvasive and quantitative nanoprobe to realize high-resolution 3D imaging of micrometer-sized specimens. The 3D density distribution of an entire mesoporous silica nanoparticle was obtained at 13 nm 3D resolution for quantitative physical and morphological analyses of its 3D pore structure. The morphological features of the whole 3D pore network and pore connectivity were examined to gain insight into the potential functions of the particles. The proposed multidistance tomographic imaging scheme with quantitative structural analyses is expected to advance studies of functional materials by facilitating their structure-based rational design.

6.
IUCrJ ; 10(Pt 6): 700-707, 2023 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-37772598

RESUMO

Photoinduced nonequilibrium phase transitions have stimulated interest in the dynamic interactions between electrons and crystalline ions, which have long been overlooked within the Born-Oppenheimer approximation. Ultrafast melting before lattice thermalization prompted researchers to revisit this issue to understand ultrafast photoinduced weakening of the crystal bonding. However, the absence of direct evidence demonstrating the role of orbital dynamics in lattice disorder leaves it elusive. By performing time-resolved resonant X-ray scattering with an X-ray free-electron laser, we directly monitored the ultrafast dynamics of bonding orbitals of Ge to drive photoinduced melting. Increased photoexcitation of bonding electrons amplifies the orbital disturbance to expedite the lattice disorder approaching the sub-picosecond scale of the nonthermal regime. The lattice disorder time shows strong nonlinear dependence on the laser fluence with a crossover behavior from thermal-driven to nonthermal-dominant kinetics, which is also verified by ab initio and two-temperature molecular dynamics simulations. This study elucidates the impact of bonding orbitals on lattice stability with a unifying interpretation on photoinduced melting.

7.
Theranostics ; 13(12): 4182-4196, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37554269

RESUMO

Background: Endothelial dysfunction is a systemic disorder and is involved in the pathogenesis of several human diseases. Hemodynamic shear stress plays an important role in vascular homeostasis including nitric oxide (NO) production. Impairment of NO production in endothelial cells stimulates the capillarization of liver sinusoidal endothelial cells, followed by hepatic stellate cell activation, inducing liver fibrosis. However, the detailed mechanism underlying NO production is not well understood. In hepatocytes, transcriptional co-activator with PDZ-binding motif (TAZ) has been reported to be involved in liver fibrosis. However, the role of endothelial TAZ in liver fibrosis has not been investigated. In this study, we uncovered the role TAZ in endothelial cell NO production, and its subsequent effects on liver fibrosis. Methods: TAZ-floxed mice were crossed with Tie2-cre transgenic mice, to generate endothelium-specific TAZ-knockout (eKO) mice. To induce liver damage, a 3,5-diethoxycarboncyl-1,4-dihydrocollidine, methionine-choline-deficient diet, or partial hepatectomy was applied. Liver fibrosis and endothelial dysfunction were analyzed in wild-type and eKO mice after liver damage. In addition, liver sinusoidal endothelial cell (LSEC) was used for in vitro assays of protein and mRNA levels. To study transcriptional regulation, chromatin immunoprecipitation and luciferase reporter assays were performed. Results: In liver of eKO mice, LSEC capillarization was observed, evidenced by loss of fenestrae and decreased LSEC-specific marker gene expression. LSEC capillarization of eKO mouse is caused by downregulation of endothelial nitric oxide synthase expression and subsequent decrease in NO concentration, which is transcriptionally regulated by TAZ-KLF2 binding to Nos3 promoter. Diminished NO concentration by TAZ knockout in endothelium accelerates liver fibrosis induced by liver damages. Conclusions: Endothelial TAZ inhibits damage-induced liver fibrosis via NO production. This highlights an unappreciated role of TAZ in vascular health and liver diseases.


Assuntos
Hepatopatias , Óxido Nítrico , Camundongos , Humanos , Animais , Óxido Nítrico/metabolismo , Células Endoteliais/metabolismo , Cirrose Hepática/metabolismo , Hepatopatias/patologia , Fígado/metabolismo , Endotélio/metabolismo
8.
J Cell Physiol ; 237(12): 4504-4516, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36250997

RESUMO

Chronic liver injury follows inflammation and liver fibrosis; however, the molecular mechanism underlying fibrosis has not been fully elucidated. In this study, the role of ductal WW domain-containing transcription regulator 1 (WWTR1)/transcriptional coactivator with PDZ-binding motif (TAZ) was investigated after liver injury. Ductal TAZ-knockout (DKO) mice showed decreased liver fibrosis following a Diethyl 1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate (DDC) diet compared to wild-type (WT) mice, as evidenced by decreased expression levels of fibrosis inducers, including connective tissue growth factor (Ctgf)/cellular communication network factor 2 (CCN2), cysteine-rich angiogenic inducer 61 (Cyr61/CCN1), and transforming growth factor beta 1 (Tgfb1), in DKO mice. Similarly, TAZ-knockout (KO) cholangiocyte organoids showed decreased expression of fibrosis inducers. Additionally, the culture supernatant of TAZ-KO cholangiocyte organoids decreased the fibrogenic gene expression in liver stellate cells. Further studies revealed that prominin 1 (PROM1/CD133) stimulated TAZ for fibrosis. After the administration of DDC diet, fibrosis was decreased in CD133-KO (CD133-KO) mice compared to that in WT mice. Similarly, CD133-KO cholangiocyte organoids showed decreased Ctgf, Cyr61, and Tgfb1 expression levels compared to WT cholangiocyte organoids. Mechanistically, CD133 stabilized TAZ via Src activation. Inhibition of Src decreased TAZ levels. Similarly, CD133-knockdown HCT116 cells showed decreased TAZ levels, but reintroduction of active Src recovered the TAZ levels. Taken together, our results suggest that TAZ facilitates liver fibrosis after a DDC diet via the CD133-Src-TAZ axis.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Doença Hepática Crônica Induzida por Substâncias e Drogas , Transativadores , Animais , Camundongos , Dieta , Fibrose , Peptídeos e Proteínas de Sinalização Intracelular , Fígado , Cirrose Hepática/induzido quimicamente , Camundongos Knockout , Fatores de Transcrição/genética , Proteínas Proto-Oncogênicas pp60(c-src) , Proteínas Adaptadoras de Transdução de Sinal/genética
9.
Nat Commun ; 13(1): 653, 2022 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-35115527

RESUMO

Mitochondria are energy-generating organelles and mitochondrial biogenesis is stimulated to meet energy requirements in response to extracellular stimuli, including exercise. However, the mechanisms underlying mitochondrial biogenesis remain unknown. Here, we demonstrate that transcriptional coactivator with PDZ-binding motif (TAZ) stimulates mitochondrial biogenesis in skeletal muscle. In muscle-specific TAZ-knockout (mKO) mice, mitochondrial biogenesis, respiratory metabolism, and exercise ability were decreased compared to wild-type mice. Mechanistically, TAZ stimulates the translation of mitochondrial transcription factor A via Ras homolog enriched in brain (Rheb)/Rheb like 1 (Rhebl1)-mTOR axis. TAZ stimulates Rhebl1 expression via TEA domain family transcription factor. Rhebl1 introduction by adeno-associated virus or mTOR activation recovered mitochondrial biogenesis in mKO muscle. Physiologically, mKO mice did not stimulate exercise-induced mitochondrial biogenesis. Collectively, our results suggested that TAZ is a novel stimulator for mitochondrial biogenesis and exercise-induced muscle adaptation.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas de Ligação a DNA/genética , Mitocôndrias Musculares/genética , Proteínas Mitocondriais/genética , Biogênese de Organelas , Condicionamento Físico Animal , Fatores de Transcrição/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Trifosfato de Adenosina/metabolismo , Animais , Linhagem Celular , Células Cultivadas , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Fibroblastos/citologia , Fibroblastos/metabolismo , Células HEK293 , Humanos , Camundongos Knockout , Mitocôndrias Musculares/metabolismo , Proteínas Mitocondriais/metabolismo , Músculo Esquelético/citologia , Músculo Esquelético/metabolismo , Mioblastos/citologia , Mioblastos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Fatores de Transcrição/metabolismo
10.
Proc Natl Acad Sci U S A ; 118(46)2021 11 16.
Artigo em Inglês | MEDLINE | ID: mdl-34750262

RESUMO

DNA molecules are atomic-scale information storage molecules that promote reliable information transfer via fault-free repetitions of replications and transcriptions. Remarkable accuracy of compacting a few-meters-long DNA into a micrometer-scale object, and the reverse, makes the chromosome one of the most intriguing structures from both physical and biological viewpoints. However, its three-dimensional (3D) structure remains elusive with challenges in observing native structures of specimens at tens-of-nanometers resolution. Here, using cryogenic coherent X-ray diffraction imaging, we succeeded in obtaining nanoscale 3D structures of metaphase chromosomes that exhibited a random distribution of electron density without characteristics of high-order folding structures. Scaling analysis of the chromosomes, compared with a model structure having the same density profile as the experimental results, has discovered the fractal nature of density distributions. Quantitative 3D density maps, corroborated by molecular dynamics simulations, reveal that internal structures of chromosomes conform to diffusion-limited aggregation behavior, which indicates that 3D chromatin packing occurs via stochastic processes.


Assuntos
Cromatina/genética , Cromossomos/genética , Linhagem Celular Tumoral , DNA/genética , Células HCT116 , Humanos , Metáfase/genética , Difração de Raios X/métodos , Raios X
11.
Sci Rep ; 11(1): 21214, 2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34707193

RESUMO

In this report, the galvanic corrosion inhibition between Cu and Ru metal films is studied, based on bonding orbital theory, using pyridinecarboxylic acid groups which show different affinities depending on the electron configuration of each metal resulting from a π-backbonding. The sp2 carbon atoms adjacent to nitrogen in the pyridine ring provide π-acceptor which forms a complex with filled d-orbital of native oxides on Cu and Ru metal film. The difference in the d-orbital electron density of each metal oxide leads to different π-backbonding strength, resulting in dense or sparse adsorption on native metal oxides. The dense adsorption layer is formed on native Cu oxide film due to the full-filled d-orbital electrons, which effectively suppresses anodic reaction in Cu film. On the other hand, only a sparse adsorption layer is formed on native Ru oxide due to its relatively weak affinity between partially filled d-orbital and pyridine groups. The adsorption behaviour is investigated through interfacial interaction analysis and electrochemical interaction evaluation. Based on this finding, the galvanic corrosion behaviour between Cu and Ru during chemical mechanical planarization (CMP) processing has been controlled.

12.
ACS Nano ; 15(3): 4066-4076, 2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33506675

RESUMO

The structures as building blocks for designing functional nanomaterials have fueled the development of versatile nanoprobes to understand local structures of noncrystalline specimens. Progress in analyzing structures of individual specimens with atomic scale accuracy has been notable recently. In most cases, however, only a limited number of specimens are inspected lacking statistics to represent the systems with structural inhomogeneity. Here, by employing single-particle imaging with X-ray free electron lasers and algorithms for multiple-model 3D imaging, we succeeded in investigating several thousand specimens in a couple of hours and identified intrinsic heterogeneities with 3D structures. Quantitative analysis has unveiled 3D morphology, facet indices, and elastic strain. The 3D elastic energy distribution is further corroborated by molecular dynamics simulations to gain mechanical insight at the atomic level. This work establishes a route to high-throughput characterization of individual specimens in large ensembles, hence overcoming statistical deficiency while providing quantitative information at the nanoscale.

13.
Clin Epigenetics ; 12(1): 66, 2020 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-32398127

RESUMO

BACKGROUND: Atherosclerosis is the main cause of cardiovascular diseases such as ischemic stroke and coronary heart disease. Gene-specific promoter methylation changes have been suggested as one of the causes underlying the development of atherosclerosis. We aimed to identify and validate specific genes that are differentially expressed through promoter methylation in atherosclerotic plaques. We performed the present study in four steps: (1) profiling and identification of gene-specific promoter methylation changes in atherosclerotic tissues; (2) validation of the promoter methylation changes of genes in plaques by comparison with non-plaque intima; (3) evaluation of promoter methylation status of the genes in vascular cellular components composing atherosclerotic plaques; and (4) evaluation of promoter methylation differences in genes among monocytes, T cells, and B cells isolated from the blood of ischemic stroke patients. RESULTS: Upon profiling, AIRE1, ALOX12, FANK1, NETO1, and SERHL2 were found to have displayed changes in promoter methylation. Of these, AIRE1 and ALOX12 displayed higher methylation levels in plaques than in non-plaque intima, but lower than those in the buffy coat of blood. Between inflammatory cells, the three genes were significantly less methylated in monocytes than in T and B cells. In the vascular cells, AIRE1 methylation was lower in endothelial and smooth muscle cells. ALOX12 methylation was higher in endothelial, but lower in smooth muscle cells. Immunofluorescence staining showed that co-localization of ALOX12 and AIRE1 was more frequent in CD14(+)-monocytes than in CD4(+)-T cell in plaque than in non-plaque intima. CONCLUSIONS: Promoter methylation changes in AIRE1 and ALOX12 occur in atherosclerosis and can be considered as novel epigenetic markers.


Assuntos
Araquidonato 12-Lipoxigenase/genética , Aterosclerose/genética , Epigênese Genética , Fatores de Transcrição/genética , Aterosclerose/metabolismo , Biomarcadores/metabolismo , Metilação de DNA , Endotélio Vascular/metabolismo , Linfócitos/metabolismo , Monócitos/metabolismo , Músculo Liso Vascular/metabolismo , Placa Aterosclerótica/genética , Regiões Promotoras Genéticas , Proteína AIRE
14.
Biochem Biophys Res Commun ; 524(1): 242-248, 2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-31983436

RESUMO

Ultraviolet (UV) irradiation induces the proliferation and differentiation of keratinocytes in the basal layer of the epidermis, which increases epidermal thickness in skin regeneration. However, the mechanism underlying this phenomenon is not yet known in detail. In this study, we aimed to demonstrate that the transcriptional coactivator with PDZ-binding motif (TAZ) stimulates epidermal regeneration by increasing keratinocyte proliferation. During epidermal regeneration, TAZ is localized in the nucleus of keratinocytes of the basal layer and stimulates epidermal growth factor receptor (EGFR) signaling. TAZ depletion in keratinocytes decreased EGFR signaling activation, which delays epidermal regeneration. Interestingly, TAZ stimulated the transcription of amphiregulin (AREG), a ligand of EGFR, through TEAD-mediated transcriptional activation. Together, these results show that TAZ stimulates EGFR signaling through AREG induction, suggesting that it plays an important role in epidermal regeneration.


Assuntos
Anfirregulina/genética , Epiderme/fisiologia , Regeneração , Transativadores/metabolismo , Transcrição Gênica , Raios Ultravioleta , Proteínas Adaptadoras de Transdução de Sinal , Anfirregulina/metabolismo , Animais , Proliferação de Células/efeitos da radiação , Epiderme/efeitos da radiação , Receptores ErbB/metabolismo , Deleção de Genes , Humanos , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Ligantes , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Regeneração/efeitos da radiação , Transdução de Sinais/efeitos da radiação , Transcrição Gênica/efeitos da radiação
15.
Biotechnol Bioeng ; 117(1): 184-193, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31560128

RESUMO

A nanoscale artificial extracellular matrix (nanoshell) formed by layer-by-layer adsorption can enhance and modulate the function of stem cells by transferring biochemical stimulus to the cell directly. Here, the nanoshell composed of fibronectin (FN) and chondroitin sulfate (CS) is demonstrated to promote chondrogenic differentiation of mesenchymal stem cells (MSCs). The multilayer structure of nanoshell is formed by repeating self-assembly of FN and CS, and its thickness can be controlled through the number of layers. The expression of chondrogenic markers in MSCs coated with the FN/CS nanoshell was increased as the number of bilayers in the nanoshell increased until four, but when it exceeds five bilayers, the effect began to decrease. Finally, the MSCs coated with optimized four bilayers of FN/CS nanoshell have high chondrogenic differentiation efficiency and showed the potential to increase formation of cartilage tissue when it is transplanted into mouse kidney. So, the precise regulation of stem cell fate at single cell level can be possible through the cellular surface modification by self-assembled polymeric film.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Condrogênese/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Nanoconchas/química , Animais , Cartilagem/metabolismo , Engenharia Celular , Sulfatos de Condroitina/química , Sulfatos de Condroitina/farmacologia , Matriz Extracelular/metabolismo , Fibronectinas/química , Fibronectinas/farmacologia , Humanos , Rim/efeitos dos fármacos , Rim/metabolismo , Células-Tronco Mesenquimais/efeitos dos fármacos , Camundongos
16.
FASEB J ; 33(5): 5914-5923, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30742777

RESUMO

In response to liver injury, the liver undergoes a regeneration process to retain its mass and function. However, the regeneration mechanism has not been fully clarified. This study investigated the role of transcriptional coactivator with PDZ-binding motif (TAZ), a Hippo-signaling effector, in liver regeneration. We observed that TAZ stimulates liver regeneration after liver injury. After partial hepatectomy (PHx) or carbon tetrachloride damage, TAZ was required for liver regeneration to increase hepatic cell proliferation and resist hepatic apoptosis, which were decreased in liver-specific TAZ knockout (LKO) mice. TAZ stimulated macrophage infiltration, resulting in IL-6 production, which induced liver regeneration. In LKO mice, IL-6-induced activation of signal transducer and activator of transcription 3, ERK, and PKB was decreased. We also observed that periductal fibrogenesis was significantly increased in LKO mice during liver regeneration after PHx, which was caused by increased hepatic apoptosis. Our results suggest that TAZ stimulates liver regeneration through IL-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.-Kim, A. R., Park, J. I., Oh, H. T., Kim, K. M., Hwang, J.-H., Jeong, M. G., Kim, E.-H., Hwang, E. S., Hong, J.-H. TAZ stimulates liver regeneration through interleukin-6-induced hepatocyte proliferation and inhibition of cell death after liver injury.


Assuntos
Interleucina-6/metabolismo , Regeneração Hepática , Fígado/lesões , Transativadores/metabolismo , Proteínas Adaptadoras de Transdução de Sinal , Alelos , Animais , Apoptose , Tetracloreto de Carbono , Morte Celular , Proliferação de Células , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Hepatectomia , Hepatócitos/citologia , Hepatócitos/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator de Transcrição STAT3/metabolismo
17.
Nat Commun ; 10(1): 421, 2019 01 24.
Artigo em Inglês | MEDLINE | ID: mdl-30679431

RESUMO

Insulin regulates blood glucose levels by binding its receptor and stimulating downstream proteins through the insulin receptor substrate (IRS). Impaired insulin signalling leads to metabolic syndrome, but the regulation of this process is not well understood. Here, we describe a novel insulin signalling regulatory pathway involving TAZ. TAZ upregulates IRS1 and stimulates Akt- and Glut4-mediated glucose uptake in muscle cells. Muscle-specific TAZ-knockout mice shows significantly decreased Irs1 expression and insulin sensitivity. Furthermore, TAZ is required for Wnt signalling-induced Irs1 expression, as observed by decreased Irs1 expression and insulin sensitivity in muscle-specific APC- and TAZ-double-knockout mice. TAZ physically interacts with c-Jun and Tead4 to induce Irs1 transcription. Finally, statin administration decreases TAZ, IRS1 level and insulin sensitivity. However, in myoblasts, the statin-mediated decrease in insulin sensitivity is counteracted by the expression of a constitutively active TAZ mutant. These results suggest that TAZ is a novel insulin signalling activator that increases insulin sensitivity and couples Hippo/Wnt signalling and insulin sensitivity.


Assuntos
Proteínas Substratos do Receptor de Insulina/metabolismo , Resistência à Insulina/fisiologia , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Fatores de Transcrição/metabolismo , Aciltransferases , Animais , Glicemia , Linhagem Celular , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Glucose/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Células HEK293 , Via de Sinalização Hippo , Humanos , Insulina/metabolismo , Camundongos , Camundongos Knockout , Células Musculares/metabolismo , Músculo Esquelético/metabolismo , Mutagênese Sítio-Dirigida , Mioblastos/metabolismo , Veículos Farmacêuticos/administração & dosagem , Sinvastatina/administração & dosagem , Sinvastatina/farmacologia , Fatores de Transcrição/genética , Regulação para Cima , Via de Sinalização Wnt
18.
Acta Biomater ; 86: 247-256, 2019 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-30594632

RESUMO

In regenerative medicine, the generation of therapeutic stem cells and tissue engineering are important for replacing damaged tissues. Numerous studies have attempted to produce cellular components that mimic the native tissue for gaining optimal function. Particularly, the extracellular matrix (ECM) composition plays an important role in cellular functions including determining the fates of mesenchymal stem cells (MSCs). Here, we evaluated the osteogenic effects of a nanofilm in which oppositely charged polyelectrolytes were alternately adsorbed onto the cell surface to create an artificial ECM environment for single MSCs. Interestingly, nanofilm composed of collagen (Col) and alginate (AA) showed relatively high stiffness and MSCs coated with the Col/AA nanofilm showed increased osteogenic differentiation efficiency compared to other nanofilm-coated MSCs. Further analysis revealed that the Col/AA nanofilm coating stimulated osteogenesis by activating transcriptional coactivators with the PDZ binding motif through extracellular signal-related kinase and p38 MAPK signaling. This nano-sized cellular coating will facilitate the development of nanotechnology for controlling cellular functions and advance stem cell-based clinical applications for regenerative medicine. STATE OF SIGNIFICANCE: In this study, we developed an artificial cellular nano-environment formed by multilayer nanofilms. We demonstrated that the nanofilms introduced to mesenchymal stem cells (MSCs) stimulate osteogenic differentiation by regulating intracellular signaling. Among the various nanofilm combinations, the induction of osteogenic gene transcription in collagen (Col) and alginate (AA) film-coated MSCs was the most pronounced compared to that on other nanofilms. A minimum number of Col/AA nanofilm bilayers (n = 2) was required for effective induction of MSC osteogenic differentiation. In addition, we observed the correlation between the promoting effect of osteogenic differentiation and stiffness of the nanofilm. Our results may be useful for developing a cell coating model system widely applicable in bioengineering and regenerative medicine.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Colágeno/farmacologia , Células-Tronco Mesenquimais/citologia , Nanopartículas/química , Osteogênese/efeitos dos fármacos , Alginatos/farmacologia , Animais , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Sistema de Sinalização das MAP Quinases , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/ultraestrutura , Nanopartículas/ultraestrutura , Fosforilação/efeitos dos fármacos , Ratos
19.
Cancer Lett ; 410: 32-40, 2017 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-28939028

RESUMO

Proto-oncogene tyrosine-protein kinase Src (cSRC) is involved in colorectal cancer (CRC) development and damage-induced intestinal regeneration, although the cellular mechanisms involved are poorly understood. Here, we report that transcriptional coactivator with PDZ binding domain (TAZ) is activated by cSRC, regulating CRC cell proliferation and tumor formation, where cSRC overexpression increases TAZ expression in CRC cells. In contrast, knockdown of cSRC decreases TAZ expression. Additionally, direct phosphorylation of TAZ at Tyr316 by cSRC stimulates nuclear localization and facilitates transcriptional enhancer factor TEF-3 (TEAD4)-mediated transcription. However, a TAZ phosphorylation mutant significantly decreased cell proliferation, wound healing, colony forming, and tumor formation. In a CRC mouse model, ApcMin/+, activated SRC expression was associated with increased TAZ expression in polyps and TAZ depletion decreased polyp formation. Moreover, intestinal TAZ knockout mice had intestinal regeneration defects following γ-irradiation. Finally, significant correspondence between SRC activation and TAZ overexpression was observed in CRC patients. These results suggest that TAZ is a critical factor for SRC-mediated intestinal tumor formation and regeneration.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adenoma/enzimologia , Proliferação de Células , Transformação Celular Neoplásica/metabolismo , Neoplasias Colorretais/enzimologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Regeneração , Quinases da Família src/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/deficiência , Proteínas Adaptadoras de Transdução de Sinal/genética , Adenoma/genética , Adenoma/patologia , Animais , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/patologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Ativação Enzimática , Feminino , Regulação Neoplásica da Expressão Gênica , Genes APC , Predisposição Genética para Doença , Células HCT116 , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Camundongos Knockout , Camundongos Nus , Mutação , Fenótipo , Fosforilação , Proto-Oncogene Mas , Transdução de Sinais , Fatores de Tempo , Transativadores , Fatores de Transcrição , Proteínas com Motivo de Ligação a PDZ com Coativador Transcricional , Quinases da Família src/genética
20.
Cent Eur J Immunol ; 42(1): 24-29, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28680328

RESUMO

AIM OF THE STUDY: We aimed to evaluate the anti-allergic effect of luteolin treatment in mice with allergic asthma and rhinitis. MATERIAL AND METHODS: Thirty-two BALB/c mice (n = 8 for each group) were used. Mice in group A (nonallergic group) were exposed to saline, while those in Group B (allergic group) were exposed to ovalbumin (OVA) intraperitoneal (i.p.) injection and intranasal (i.n.) challenge. Null treatment group (Group C) received sterile saline (150 µl) i.p. injection, 30 minutes before each i.n. challenge. Finally, the treatment group (Group D) received luteolin (0.1 mg/kg) by i.p. injection, 30 minutes before each i.n. challenge. We evaluated the number of inflammatory cells including eosinophils, neutrophils and lymphocytes in bronchoalveolar lavage (BAL) fluid, the titers of IL-4, IL-5 and IL-13 in lung homogenate, and we also evaluated histopathologic findings, including infiltration of inflammatory cells into the pulmonary parenchyma and nasal mucosa. RESULTS: After the OVA challenge, the number of eosinophils, neutrophils and lymphocytes in BAL fluid was significantly increased in group B, compared to group A (p < 0.001). Mice in group C had no significant difference (p > 0.05). On the other hand, group D showed a significant decrease in all inflammatory cells compared to group B (p < 0.05). Also, group D showed a significant decrease in IL-4, IL-5 and IL-13 in their lung homogenate compared to groups B and C (p < 0.05). Group D also showed a significant decrease in inflammatory cell infiltration after luteolin treatment (p < 0.05). CONCLUSION: Luteolin had an anti-allergic effect in a murine model of allergic asthma and rhinitis.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...