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1.
Ecotoxicol Environ Saf ; 226: 112835, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34600292

RESUMO

Halobenzoquinones (HBQs) are emerging and widespread disinfection byproducts (DBPs), but their toxicological mechanisms to aquatic organisms remain elusive. Herein, we evaluated oxidative stress, cardiac toxicity, and cerebral toxicity after 2, 6-dichloro-1, 4-benzoquinone (2,6-DCBQ) exposure in zebrafish. Adult zebrafish were respectively exposed to 0.25, 0.5, and 1 µM 2,6-DCBQ for 96 h. The mortality rate of 2,6-DCBQ (1 µM) was 10%, while the LC50 value was 1.532 µM. Besides, 2,6-DCBQ exposure caused irregularity and elimination of myocardial fiber in the heart, and the pyknosis of nuclears and the agglutination of chromatin in the brain. We measured the 2,6-DCBQ-induced oxidative stresses in the heart and brain. Additionally, the glutathione (GSH) content, superoxide dismutase (SOD) activity, catalase (CAT) activity, and total antioxidant capacity (T-AOC) were significantly inhibited. To better understand the potential toxicity of 2,6-DCBQ, transcriptomic analysis was performed in the control and 1 µM group after 96 h exposure. As a result, 545 and 1228 differentially expressed genes (DEGs) were detected in the heart and brain, respectively. GO analysis revealed that these DEGs were primarily enriched in blood vessel development, vasculature development, and oxidoreductase activity in the heart; response to stimulus, nervous system development, and oxidoreductase activity in the brain. KEGG enrichment analysis indicated that the DEGs were mainly enriched in VEGF signaling pathway and vascular smooth muscle contraction pathway in the heart; neuroactive ligand-receptor interaction, and NOD-like receptor signaling pathway in the brain. These findings exposed the underlying toxicity mechanism of 2,6-DCBQ exposure on zebrafish cardiovascular and brain systems.


Assuntos
Água Potável , Poluentes Químicos da Água , Animais , Benzoquinonas , Encéfalo , Água Potável/análise , Estresse Oxidativo , Transcriptoma , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/genética
2.
J Immunol ; 197(5): 1683-91, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27465533

RESUMO

Exploring the mechanisms controlling lymphocyte trafficking is essential for understanding the function of the immune system and the pathophysiology of immunodeficiencies. The mammalian Ste20-like kinase 1 (Mst1) has been identified as a critical signaling mediator of T cell migration, and loss of Mst1 results in immunodeficiency disease. Although Mst1 is known to support T cell migration through induction of cell polarization and lamellipodial formation, the downstream effectors of Mst1 are incompletely defined. Mice deficient for the actin-bundling protein L-plastin (LPL) have phenotypes similar to mice lacking Mst1, including decreased T cell polarization, lamellipodial formation, and cell migration. We therefore asked whether LPL functions downstream of Mst1. The regulatory N-terminal domain of LPL contains a consensus Mst1 phosphorylation site at Thr(89) We found that Mst1 can phosphorylate LPL in vitro and that Mst1 can interact with LPL in cells. Removal of the Mst1 phosphorylation site by mutating Thr(89) to Ala impaired localization of LPL to the actin-rich lamellipodia of T cells. Expression of the T89A LPL mutant failed to restore migration of LPL-deficient T cells in vitro. Furthermore, expression of T89A LPL in LPL-deficient hematopoietic cells, using bone marrow chimeras, failed to rescue the phenotype of decreased thymic egress. These results identify LPL as a key effector of Mst1 and establish a novel mechanism linking a signaling intermediate to an actin-binding protein critical to T cell migration.


Assuntos
Movimento Celular , Fosfoproteínas/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais , Linfócitos T/imunologia , Animais , Proteínas do Citoesqueleto , Citometria de Fluxo , Ativação Linfocitária , Linfócitos/imunologia , Camundongos , Proteínas dos Microfilamentos , Fosfoproteínas/deficiência , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Transporte Proteico , Pseudópodes/imunologia , Pseudópodes/fisiologia
3.
Exp Cell Res ; 319(8): 1124-35, 2013 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-23454549

RESUMO

In polarized, migrating cells, stress fibers are a highly dynamic network of contractile acto-myosin structures composed of bundles of actin filaments held together by actin cross-linking proteins such as α-actinins. As such, α-actinins influence actin cytoskeleton organization and dynamics and focal adhesion maturation. In response to environmental signals, α-actinins are tyrosine phosphorylated and this affects their binding to actin stress fibers; however, the cellular role of α-actinin tyrosine phosphorylation remains largely unknown. We found that non-muscle α-actinin1/4 are critical for the establishment of dorsal stress fibers and maintenance of transverse arc stress fibers. Analysis of cells genetically depleted of α-actinin1 and 4 reveals two distinct modes for focal adhesion maturation. An α-actinin1 or 4 dependent mode that uses dorsal stress fiber precursors as a template for establishing focal adhesions and their maturation, and an α-actinin-independent manner that uses transverse arc precursors to establish focal adhesions at both ends. Focal adhesions formed in the absence of α-actinins are delayed in their maturation, exhibit altered morphology, have decreased amounts of Zyxin and VASP, and reduced adhesiveness to extracellular matrix. Further rescue experiments demonstrate that the tyrosine phosphorylation of α-actinin1 at Y12 and α-actinin4 at Y265 is critical for dorsal stress fiber establishment, transverse arc maintenance and focal adhesion maturation.


Assuntos
Actinina/metabolismo , Adesões Focais/fisiologia , Proteínas Tirosina Quinases/metabolismo , Fibras de Estresse/metabolismo , Fibras de Estresse/fisiologia , Actinina/genética , Actinina/fisiologia , Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Quinase 1 de Adesão Focal/metabolismo , Adesões Focais/química , Adesões Focais/genética , Adesões Focais/metabolismo , Células HEK293 , Humanos , Proteínas dos Microfilamentos/metabolismo , Paxilina/metabolismo , Fosfoproteínas/metabolismo , Fosforilação/genética , Fosforilação/fisiologia , Proteínas Tirosina Quinases/fisiologia , Tirosina/genética , Tirosina/metabolismo , Zixina/metabolismo
4.
Biophys J ; 105(10): 2289-300, 2013 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-24268141

RESUMO

A wide range of invasive pathological outcomes originate from the loss of epithelial phenotype and involve either loss of function or downregulation of transmembrane adhesive receptor complexes, including Ecadherin (Ecad) and binding partners ß-catenin and α-catenin at adherens junctions. Cellular pathways regulating wild-type ß-catenin level, or direct mutations in ß-catenin that affect the turnover of the protein have been shown to contribute to cancer development, through induction of uncontrolled proliferation of transformed tumor cells, particularly in colon cancer. Using single-molecule force spectroscopy, we show that depletion of ß-catenin or the prominent cancer-related S45 deletion mutation in ß-catenin present in human colon cancers both weaken tumor intercellular Ecad/Ecad bond strength and diminishes the capacity of specific extracellular matrix proteins-including collagen I, collagen IV, and laminin V-to modulate intercellular Ecad/Ecad bond strength through α-catenin and the kinase activity of glycogen synthase kinase 3 (GSK-3ß). Thus, in addition to regulating tumor cell proliferation, cancer-related mutations in ß-catenin can influence tumor progression by weakening the adhesion of tumor cells to one another through reduced individual Ecad/Ecad bond strength and cellular adhesion to specific components of the extracellular matrix and the basement membrane.


Assuntos
Caderinas/metabolismo , Espaço Extracelular/metabolismo , beta Catenina/metabolismo , Sequência de Bases , Adesão Celular/genética , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Proteínas da Matriz Extracelular/metabolismo , Regulação Neoplásica da Expressão Gênica , Quinase 3 da Glicogênio Sintase/metabolismo , Glicogênio Sintase Quinase 3 beta , Humanos , Ligação Proteica , Deleção de Sequência , beta Catenina/genética
5.
Proc Natl Acad Sci U S A ; 107(7): 2938-43, 2010 Feb 16.
Artigo em Inglês | MEDLINE | ID: mdl-20133701

RESUMO

Corepressors play an essential role in nuclear receptor-mediated transcriptional repression. In general, corepressors directly bind to nuclear receptors via CoRNR boxes (L/I-X-X-I/V-I) in the absence of ligand and appear to act as scaffolds to further recruit chromatin remodeling complexes to specific target genes. Here, we describe the identification of the multiple LIM domain protein Ajuba as a unique corepressor for a subset of nuclear hormone receptors. Ajuba contains functional nuclear-receptor interacting motifs and selectively interacts with retinoic acid receptors (RARs) and rexinoid receptor (RXRs) subtypes in a ligand-dependent manner. Simultaneous mutation of these motifs abolishes RAR binding and concomitantly leads to loss of repression on RARE reporter genes. P19 cells depleted of Ajuba are highly sensitized to all-trans retinoic acid (atRA)-induced transcription and differentiation. In the absence of atRA, Ajuba can be readily found at the RARE control elements of RAR endogenous target genes. Stimulation of cells with atRA results in the dissociation of Ajuba from these regions. Moreover, we observed that coexpression of the known Ajuba binding partner Prmt5 (protein arginine methyltransferase-5) inhibited the Ajuba/RAR interaction. The high-affinity Ajuba-RAR/RXR interaction site overlaps the region responsible for Ajuba/Prmt5 binding, and thus binding appears to be mutually exclusive, providing a potential mechanism for these observations. Identification of Ajuba as a unique corepressor for nuclear receptors sheds new light on mechanisms for nuclear receptor-mediated repression and provides a unique target for developing more effective therapeutics to modulate this important pathway.


Assuntos
Proteínas Correpressoras/metabolismo , Regulação da Expressão Gênica/fisiologia , Proteínas de Homeodomínio/metabolismo , Receptores Citoplasmáticos e Nucleares/metabolismo , Transdução de Sinais/fisiologia , Tretinoína/metabolismo , Motivos de Aminoácidos/genética , Motivos de Aminoácidos/fisiologia , Animais , Western Blotting , Linhagem Celular , Imunoprecipitação da Cromatina , Humanos , Imunoprecipitação , Proteínas com Domínio LIM , Luciferases , Camundongos , Microscopia de Fluorescência , Ligação Proteica , Proteína-Arginina N-Metiltransferases/metabolismo , Receptores do Ácido Retinoico/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
6.
Proc Natl Acad Sci U S A ; 105(47): 18331-6, 2008 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-19017792

RESUMO

alpha-Catenin is essential in cadherin-mediated epithelium development and maintenance of tissues and in cancer progression and metastasis. However, recent studies question the conventional wisdom that alpha-catenin directly bridges the cadherin adhesion complex to the actin cytoskeleton. Therefore, whether alpha-catenin plays a direct role in cadherin-dependent cell adhesion is unknown. Here, single-molecule force spectroscopy measurements in cells depleted of alpha-catenin or expressing the hereditary diffuse gastric cancer associated V832M E-cadherin germ-line missense mutation show that alpha-catenin plays a critical role in cadherin-mediated intercellular recognition and subsequent multibond formation within the first 300 ms of cell contact. At short contact times, alpha-catenin mediates a 30% stronger interaction between apposing E-cadherin molecules than when it cannot bind the E-cadherin-beta-catenin complex. As contact time between cells increases, alpha-catenin is essential for the strengthening of the first intercellular cadherin bond and for the ensuing formation of additional bonds between the cells, all without the intervention of actin. These results suggest that a critical decision to form an adhesion complex between 2 cells occurs within an extremely short time span and at a single-molecule level and identify a previously unappreciated role for alpha-catenin in these processes.


Assuntos
Caderinas/fisiologia , Adesão Celular/fisiologia , alfa Catenina/fisiologia , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Imunoprecipitação , Microscopia de Força Atômica , Ligação Proteica , RNA Interferente Pequeno/genética , Sensibilidade e Especificidade , Transfecção
7.
Gene ; 788: 145673, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33882324

RESUMO

Type I collagen is a major extracellular matrix (ECM) component in the interstitial stroma of solid tumors, and it represents the first barrier against tumor cell invasion after basement-membrane degradation. The collagen receptors that convey molecular signals into the cells are collagen-binding discoidin domain receptors (DDRs) and integrins. Collagen-activated DDR2 clusters form DDR2-containing remnants in an integrin-dependent manner in three-dimensional (3D) collagen matrix. Although DDR2-containing remnants in the collagen matrix may generate sustained perturbation to ECM remodeling, the molecular components and function of the remnants are largely unknown. Here we determined the interaction and co-localization between DDR2 and membrane type I-matrix metalloproteinase (MT1-MMP) in the cells and the DDR2-containing remnants on collagen fibers, and we found that MT1-MMP was co-tethered to collagen fibers in the remnants. These collagen fiber-associated MT1-MMP remained active. Furthermore, DDR2 enhanced MT1-MMP proteolytic activity. These results demonstrate that DDR2 ensures the remnant-associated MT1-MMP to continue the degradation of ECM in addition to pericellular ECM degradation mediated by cell surface tethered MT1-MMP. Thus, our findings reveal a new alternative ECM degradation mechanism mediated by MT1-MMP in the DDR2-containing remnants.


Assuntos
Neoplasias da Mama/metabolismo , Colágeno Tipo I/metabolismo , Receptor com Domínio Discoidina 2/metabolismo , Fibrossarcoma/metabolismo , Metaloproteinase 14 da Matriz/metabolismo , Linhagem Celular Tumoral , Movimento Celular , Receptor com Domínio Discoidina 2/química , Matriz Extracelular/metabolismo , Feminino , Humanos , Metaloproteinase 14 da Matriz/química , Microscopia Confocal , Ligação Proteica , Imagem com Lapso de Tempo
8.
J Biol Chem ; 284(27): 18252-9, 2009 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-19458087

RESUMO

The progression of several human cancers correlates with the loss of cytoplasmic protein alpha-catenin from E-cadherin-rich intercellular junctions and loss of adhesion. However, the potential role of alpha-catenin in directly modulating the adhesive function of individual E-cadherin molecules in human cancer is unknown. Here we use single-molecule force spectroscopy to probe the tensile strength, unstressed bond lifetime, and interaction energy between E-cadherins expressed on the surface of live human parental breast cancer cells lacking alpha-catenin and these cells where alpha-catenin is re-expressed. We find that the tensile strength and the lifetime of single E-cadherin/E-cadherin bonds between parental cells are significantly lower over a wide range of loading rates. Statistical analysis of the force displacement spectra reveals that single cadherin bonds between cancer cells feature an exceedingly low energy barrier against tensile forces and low molecular stiffness. Disassembly of filamentous actin using latrunculin B has no significant effect on the strength of single intercellular E-cadherin bonds. The absence of alpha-catenin causes a dominant negative effect on both global cell-cell adhesion and single E-cadherin bond strength. These results suggest that the loss of alpha-catenin alone drastically reduces the adhesive force between individual cadherin pairs on adjoining cells, explain the global loss of cell adhesion in human breast cancer cells, and show that the forced expression of alpha-catenin in cancer cells can restore both higher intercellular avidity and intercellular E-cadherin bond strength.


Assuntos
Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Caderinas/metabolismo , Adesão Celular/fisiologia , alfa Catenina/metabolismo , Linhagem Celular Tumoral , Epitélio/metabolismo , Epitélio/patologia , Feminino , Humanos , Junções Intercelulares/metabolismo , Microscopia de Força Atômica , Pessoa de Meia-Idade , Análise Espectral , Resistência à Tração/fisiologia , Transfecção , alfa Catenina/genética
9.
J Cell Biol ; 168(5): 813-24, 2005 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-15728191

RESUMO

Cell migration requires extension of lamellipodia that are stabilized by formation of adhesive complexes at the leading edge. Both processes are regulated by signaling proteins recruited to nascent adhesive sites that lead to activation of Rho GTPases. The Ajuba/Zyxin family of LIM proteins are components of cellular adhesive complexes. We show that cells from Ajuba null mice are inhibited in their migration, without associated abnormality in adhesion to extracellular matrix proteins, cell spreading, or integrin activation. Lamellipodia production, or function, is defective and there is a selective reduction in the level and tyrosine phosphorylation of FAK, p130Cas, Crk, and Dock180 at nascent focal complexes. In response to migratory cues Rac activation is blunted in Ajuba null cells, as detected biochemically and by FRET analysis. Ajuba associates with the focal adhesion-targeting domain of p130Cas, and rescue experiments suggest that Ajuba acts upstream of p130Cas to localize p130Cas to nascent adhesive sites in migrating cells thereby leading to the activation of Rac.


Assuntos
Movimento Celular/fisiologia , Proteínas de Homeodomínio/metabolismo , Proteínas/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Proteína Substrato Associada a Crk , Proteínas do Citoesqueleto/metabolismo , Proteínas da Matriz Extracelular/metabolismo , Fibroblastos/fisiologia , Quinase 1 de Adesão Focal , Proteína-Tirosina Quinases de Adesão Focal , Proteínas com Domínio LIM , Camundongos , Paxilina , Fosfoproteínas/metabolismo , Proteínas Tirosina Quinases/metabolismo , Pseudópodes/metabolismo , Proteína p130 Retinoblastoma-Like , Fatores de Tempo
10.
Abdom Radiol (NY) ; 44(7): 2466-2473, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30937505

RESUMO

OBJECTIVE: This study examined radiological imaging features of small (≤ 3 cm) and large (> 3 cm) adenosquamous carcinomas of the pancreas (PASC) lesions to better understand the morphology of these lesions. METHODS: Images from 110 patients with pathologically proven PASC (80 males and 30 females, mean age: 62.6 years) were retrospectively reviewed. Two radiologists analyzed images and reached a consensus regarding the following features: location, shape, margins, presence of solid and necrotic components, rim enhancement, density/intensity during the portal venous phase, invasion of surrounding organs, vascular invasion, venous tumor thrombus formation, and enlarged lymph nodes. Differences in the imaging features between the two groups were evaluated with the Chi-square test or Fisher's exact test. RESULTS: There were 41 small PASC lesions (mean age: 60.59 years) and 69 large PASC lesions (63.74 years). Statistical analysis demonstrated significant differences in the location, shape, adjacent organ and vessel invasion, and venous tumor thrombus formation (P < 0.05). Small PASC lesions were more frequently detected in the pancreatic head and had an ovoid shape. There was no significant difference in the presence of solid and necrotic components (P = 0.090), including approximately 3/4 of the lesions with necrosis and 1/4 purely solid lesions, enlarged lymph nodes (P = 0.068) and other features. CONCLUSION: Regardless of the tumor size, 75% of PASC lesions present with central necrosis while 25% are purely solid. Small PASC lesions can be associated with lymph node metastasis at a relatively early stage. Large PASC lesions are likely to invade adjacent tissues and be associated with venous tumor thrombus formation.


Assuntos
Carcinoma Adenoescamoso/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Neoplasias Pancreáticas/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pâncreas/diagnóstico por imagem , Estudos Retrospectivos
11.
Int J Biol Sci ; 14(6): 654-666, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29904280

RESUMO

Cell-matrix interactions play critical roles in cell adhesion, tissue remodeling and cancer metastasis. Discoidin domain receptor 2 (DDR2) is a collagen receptor belonging to receptor tyrosine kinase (RTK) family. It is a powerful regulator of collagen deposition in the extracellular matrix (ECM). Although the oligomerization of DDR extracellular domain (ECD) proteins can affect matrix remodeling by inhibiting fibrillogenesis, it is still unknown how cellular DDR2 is incorporated into collagen matrix. Using 3-dimentional (3D) imaging for migrating cells, we identified a novel mechanism that explains how DDR2 incorporating into collagen matrix, which we named as posterior remnant tethering. We followed the de novo formation of these remnants and identified that DDR2 clusters formed at the retracting phase of a pseudopodium, then these clusters were tethered to fibrillar collagen and peeled off from the cell body to generate DDR2 containing posterior remnants. Inhibition of ß1-integrin or Rac1 activity abrogated the remnant formation. Thus, our findings unveil a special cellular mechanism for DDR2 clusters incorporating into collagen matrix in an integrin-dependent manner.


Assuntos
Colágeno/metabolismo , Receptor com Domínio Discoidina 2/metabolismo , Integrinas/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/genética , Movimento Celular/fisiologia , Colágeno/genética , Receptor com Domínio Discoidina 2/genética , Matriz Extracelular/genética , Matriz Extracelular/metabolismo , Humanos , Integrinas/genética , Microscopia Confocal , Ratos
12.
Sci Rep ; 8(1): 4054, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29497089

RESUMO

A correction has been published and is linked to the HTML and PDF versions of this paper. The error has not been fixed in the paper.

13.
Ultrason Sonochem ; 14(1): 67-74, 2007 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-16690343

RESUMO

Copper-chromite oxide and TiO2-supported copper-chromite oxide catalysts are prepared by various methods. They are characterized with ICP, BET, XRD, XPS, SEM, and TEM, etc. Their catalytic performance for liquid phase hydrogenation of furfural to furfuryl alcohol is also valuated. The catalysts prepared by ultrasound exhibit good performance. Catalytic activity of TiO2-supported catalysts is higher than that of catalyst without TiO2, notwithstanding they are all prepared by ultrasound. It is worth stressing that after reduced the TiO2-supported catalysts, which are X-ray amorphous, display good performance at 140 degrees C, while the catalysts without TiO2 show no activity under the same condition. Obtained results indicate that the catalytic performance of catalysts depends upon the amount of reducible copper ions and the activity decay is related to the loss of metal elements on the surface of catalyst.


Assuntos
Furaldeído/química , Furaldeído/efeitos da radiação , Furanos/química , Hidrogênio/química , Hidrogênio/efeitos da radiação , Sonicação , Catálise , Furanos/efeitos da radiação
14.
Sci Rep ; 7(1): 1485, 2017 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-28469254

RESUMO

V-domain Immunoglobulin Suppressor of T cell Activation (VISTA) is an inhibitory immune-checkpoint molecule that suppresses CD4+ and CD8+ T cell activation when expressed on antigen-presenting cells. Vsir -/- mice developed loss of peripheral tolerance and multi-organ chronic inflammatory phenotypes. Vsir -/- CD4+ and CD8+ T cells were hyper-responsive towards self- and foreign antigens. Whether or not VISTA regulates innate immunity is unknown. Using a murine model of psoriasis induced by TLR7 agonist imiquimod (IMQ), we show that VISTA deficiency exacerbated psoriasiform inflammation. Enhanced TLR7 signaling in Vsir -/- dendritic cells (DCs) led to the hyper-activation of Erk1/2 and Jnk1/2, and augmented the production of IL-23. IL-23, in turn, promoted the expression of IL-17A in both TCRγδ+ T cells and CD4+ Th17 cells. Furthermore, VISTA regulates the peripheral homeostasis of CD27- γδ T cells and their activation upon TCR-mediated or cytokine-mediated stimulation. IL-17A-producing CD27- γδ T cells were expanded in the Vsir -/- mice and amplified the inflammatory cascade. In conclusion, this study has demonstrated that VISTA critically regulates the inflammatory responses mediated by DCs and IL-17-producing TCRγδ+ and CD4+ Th17 T cells following TLR7 stimulation. Our finding provides a rationale for therapeutically enhancing VISTA-mediated pathways to benefit the treatment of autoimmune and inflammatory disorders.


Assuntos
Imunidade Inata , Inflamação/imunologia , Interleucina-17/imunologia , Interleucina-23/imunologia , Proteínas de Membrana/imunologia , Animais , Citocinas/imunologia , Imiquimode/administração & dosagem , Inflamação/complicações , Mediadores da Inflamação/imunologia , Linfócitos Intraepiteliais/imunologia , Proteínas de Membrana/genética , Camundongos Knockout , Psoríase/induzido quimicamente , Psoríase/imunologia , Transdução de Sinais , Células Th17/imunologia
15.
JCI Insight ; 1(17): e86330, 2016 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-27777970

RESUMO

Mutations of the Plekhm1 gene in humans and rats cause osteopetrosis, an inherited bone disease characterized by diminished bone resorption by osteoclasts. PLEKHM1 binds to RAB7 and is critical for lysosome trafficking. However, the molecular mechanisms by which PLEKHM1 regulates lysosomal pathways remain unknown. Here, we generated germline and conditional Plekhm1-deficient mice. These mice displayed no overt abnormalities in major organs, except for an increase in trabecular bone mass. Furthermore, loss of PLEKHM1 abrogated the peripheral distribution of lysosomes and bone resorption in osteoclasts. Mechanistically, we indicated that DEF8 interacts with PLEKHM1 and promotes its binding to RAB7, whereas the binding of FAM98A and NDEL1 with PLEKHM1 connects lysosomes to microtubules. Importantly, suppression of these proteins results in lysosome positioning and bone resorption defects similar to those of Plekhm1-null osteoclasts. Thus, PLHKEM1, DEF8, FAM98A, and NDEL1 constitute a molecular complex that regulates lysosome positioning and secretion through RAB7.


Assuntos
Reabsorção Óssea , Lisossomos/fisiologia , Osteoclastos/fisiologia , Proteínas de Transporte Vesicular/fisiologia , Proteínas rab de Ligação ao GTP/fisiologia , Proteínas Adaptadoras de Transdução de Sinal , Animais , Proteínas Relacionadas à Autofagia , Diferenciação Celular , Células Cultivadas , Endossomos , Deleção de Genes , Homeostase , Camundongos , Camundongos Endogâmicos C57BL , Proteínas de Transporte Vesicular/genética , proteínas de unión al GTP Rab7
16.
Sci Rep ; 5: 14580, 2015 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-26423227

RESUMO

Multiple attributes of the three-dimensional (3D) extracellular matrix (ECM) have been independently implicated as regulators of cell motility, including pore size, crosslink density, structural organization, and stiffness. However, these parameters cannot be independently varied within a complex 3D ECM protein network. We present an integrated, quantitative study of these parameters across a broad range of complex matrix configurations using self-assembling 3D collagen and show how each parameter relates to the others and to cell motility. Increasing collagen density resulted in a decrease and then an increase in both pore size and fiber alignment, which both correlated significantly with cell motility but not bulk matrix stiffness within the range tested. However, using the crosslinking enzyme Transglutaminase II to alter microstructure independently of density revealed that motility is most significantly predicted by fiber alignment. Cellular protrusion rate, protrusion orientation, speed of migration, and invasion distance showed coupled biphasic responses to increasing collagen density not predicted by 2D models or by stiffness, but instead by fiber alignment. The requirement of matrix metalloproteinase (MMP) activity was also observed to depend on microstructure, and a threshold of MMP utility was identified. Our results suggest that fiber topography guides protrusions and thereby MMP activity and motility.


Assuntos
Movimento Celular , Metaloproteinase 14 da Matriz/fisiologia , Técnicas de Cultura de Células , Linhagem Celular Tumoral , Forma Celular , Meios de Cultura , Matriz Extracelular/enzimologia , Colágenos Fibrilares/química , Colágenos Fibrilares/ultraestrutura , Proteínas de Ligação ao GTP , Humanos , Proteína 2 Glutamina gama-Glutamiltransferase , Estrutura Quaternária de Proteína , Transglutaminases
17.
Artigo em Inglês | MEDLINE | ID: mdl-12219200

RESUMO

By the study of in vivo induction of rabbit 2',5'-oligoadenylate synthetase (2',5'-OASE), it has been found that polyinosinic acid-polycytidylic acid (poly(I).poly(C)) can induce the formation of 2',5'-OASE only in rabbit peripheral blood mononuclear cells(PBMC), whereas New Castle disease virus (NDV) and erythropoietin (EPO) are capable of enhancing 2',5'-OASE level in the total red blood capsule (RBC) as well as in PBMC. It has been demonstrated that the enzyme is located in reticulocytes and that the increase of 2',5'-OASE level by phenylhydrazine, NDV, EPO in RBC is proportionally related to the increase of reticulocytes. The level of 2',5'-OASE in PBMC from rabbit treated with poly(I).poly(C), NDV, EPO is 6 times higher than that of the control, suggesting an induction effect occurs. Considering that poly(I).poly(C) and NDV are highly efficient inducers of rabbit interferon and that the induction kinetics by EPO is similar to that by interferon, it is reasonable to postulate that the induction effect of the two former agents are mediated by interferon, while the latter initiates induction directly.

18.
Artigo em Inglês | MEDLINE | ID: mdl-12219201

RESUMO

Only one 2',5'-oligoadenylate synthetase (2',5'-OASE) with a mass of 110 kD is present in the NDV-induced rabbit reticulocytes, whereas two 2',5'-OASE isozymes with mass of 110 kD and 40 kD respectively exist in the NDV-treated rabbit spleen. The large 110 kD enzymes from reticulocytes and spleen are associated with the ribosome. The small enzyme from spleen has been found in both the cytosol and ribosomal pellet. The characterization of the large enzymes purified from NDV-induced reticulocytes and spleen show that the 110 kD enzymes are the same one, and identical to the enzyme from phenylhydrazine-induced rabbit reticulocytes, suggesting that they are most likely encoded by the same gene, although their induction pathway and tissue distribution pattern are different. It is postulated that the 40 kD 2',5'-OASE from rabbit spleen and the large enzyme are isozymes with different physiological functions, considering that they require different conditions for catalytic reaction reaction and are located in different subcellular fractions.

19.
Br J Pharmacol ; 166(8): 2212-27, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22352842

RESUMO

BACKGROUND AND PURPOSE: Diabetes is characterized by hyperglycaemia, which facilitates the formation of advanced glycation end-products (AGEs). Type 2 diabetes mellitus is commonly accompanied by non-alcoholic steatohepatitis, which could lead to hepatic fibrosis. Receptor for AGEs (RAGE) mediates effects of AGEs and is associated with increased oxidative stress, cell growth and inflammation. The phytochemical curcumin inhibits the activation of hepatic stellate cells (HSCs), the major effectors during hepatic fibrogenesis. The aim of this study was to explore the underlying mechanisms of curcumin in the elimination of the stimulating effects of AGEs on the activation of HSCs. We hypothesize that curcumin eliminates the effects of AGEs by suppressing gene expression of RAGE. EXPERIMENTAL APPROACH: Gene promoter activities were evaluated by transient transfection assays. The expression of rage was silenced by short hairpin RNA. Gene expression was analysed by real-time PCR and Western blots. Oxidative stress was evaluated. KEY RESULTS: AGEs induced rage expression in cultured HSCs, which played a critical role in the AGEs-induced activation of HSCs. Curcumin at 20 µM eliminated the AGE effects, which required the activation of PPARγ. In addition, curcumin attenuated AGEs-induced oxidative stress in HSCs by elevating the activity of glutamate-cysteine ligase and by stimulating de novo synthesis of glutathione, leading to the suppression of gene expression of RAGE. CONCLUSION AND IMPLICATIONS: Curcumin suppressed gene expression of RAGE by elevating the activity of PPARγ and attenuating oxidative stress, leading to the elimination of the AGE effects on the activation of HSCs. LINKED ARTICLE: This article is commented on by Stefanska, pp. 2209-2211 of this issue. To view this commentary visit http://dx.doi.org/10.1111/j.1476-5381.2012.01959.x.


Assuntos
Curcumina/farmacologia , Células Estreladas do Fígado/metabolismo , PPAR gama/metabolismo , Receptores Imunológicos/metabolismo , Animais , Regulação da Expressão Gênica/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Glutationa/metabolismo , Células Estreladas do Fígado/efeitos dos fármacos , Peroxidação de Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nitrocompostos/farmacologia , Estresse Oxidativo , PPAR gama/genética , RNA/genética , RNA/metabolismo , RNA Interferente Pequeno , Ratos , Ratos Sprague-Dawley , Espécies Reativas de Oxigênio , Reação em Cadeia da Polimerase em Tempo Real , Receptor para Produtos Finais de Glicação Avançada , Receptores Imunológicos/genética , Tiazóis/farmacologia
20.
Nat Commun ; 3: 719, 2012 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-22395610

RESUMO

Spontaneous molecular oscillations are ubiquitous in biology. But to our knowledge, periodic cell migratory patterns have not been observed. Here we report the highly regular, periodic migration of cells along rectilinear tracks generated inside three-dimensional matrices, with each excursion encompassing several cell lengths, a phenotype that does not occur on conventional substrates. Short hairpin RNA depletion shows that these one-dimensional oscillations are uniquely controlled by zyxin and binding partners α-actinin and p130Cas, but not vasodilator-stimulated phosphoprotein and cysteine-rich protein 1. Oscillations are recapitulated for cells migrating along one-dimensional micropatterns, but not on two-dimensional compliant substrates. These results indicate that although two-dimensional motility can be well described by speed and persistence, three-dimensional motility requires two additional parameters, the dimensionality of the cell paths in the matrix and the temporal control of cell movements along these paths. These results also suggest that the zyxin/α-actinin/p130Cas module may ensure that motile cells in a three-dimensional matrix explore the largest space possible in minimum time.


Assuntos
Actinina/metabolismo , Movimento Celular , Proteína Substrato Associada a Crk/metabolismo , Zixina/metabolismo , Proteínas de Transporte/metabolismo , Moléculas de Adesão Celular/metabolismo , Linhagem Celular Tumoral , Adesões Focais/metabolismo , Humanos , Proteínas com Domínio LIM/metabolismo , Proteínas dos Microfilamentos/metabolismo , Fosfoproteínas/metabolismo , Interferência de RNA , RNA Interferente Pequeno
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