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1.
Am J Emerg Med ; 55: 228.e1-228.e3, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35058085

RESUMEN

We describe a case of acute respiratory failure caused by inhalation of gas formed from a reaction of intentional dissolution of sodium dichloroisocyanurate (NaDCC) tablets in water. A patient had refractory respiratory failure despite the use of conventional therapy, including lung-protective mechanical ventilation. Early veno-venous extracorporeal membrane oxygenation (VV-ECMO) support was initiated in the emergency department (ED). The patient was weaned from ECMO on hospital day 6 and discharged from the ICU on hospital day 27. Cases of severe inhalation injury with acute respiratory failure refractory to conventional treatments and mechanical ventilator support may benefit from VV-ECMO. Literature on early initiation of ED-VV-ECMO in NaDCC-induced refractory respiratory failure is rare. This case may be used as a guide in the management of subsequent cases as it shows that early initiation of ED-VV-ECMO was beneficial to the patient.


Asunto(s)
Oxigenación por Membrana Extracorpórea , Síndrome de Dificultad Respiratoria , Insuficiencia Respiratoria , Servicio de Urgencia en Hospital , Humanos , Respiración Artificial , Insuficiencia Respiratoria/etiología , Insuficiencia Respiratoria/terapia
2.
Cell Oncol (Dordr) ; 44(6): 1287-1305, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34582006

RESUMEN

PURPOSE: Spatiotemporal regulation of cell membrane dynamics is a major process that promotes cancer cell invasion by acting as a driving force for cell migration. Beta-Pix (ßPix), a guanine nucleotide exchange factor for Rac1, has been reported to be involved in actin-mediated cellular processes, such as cell migration, by interacting with various proteins. As yet, however, the molecular mechanisms underlying ßPix-mediated cancer cell invasion remain unclear. METHODS: The clinical significance of ßPix was analyzed in patients with colorectal cancer (CRC) using public clinical databases. Pull-down and immunoprecipitation assays were employed to identify novel binding partners for ßPix. Additionally, various cell biological assays including immunocytochemistry and time-lapse video microscopy were performed to assess the effects of ßPix on CRC progression. A ßPix-SH3 antibody delivery system was used to determine the effects of the ßPix-Dyn2 complex in CRC cells. RESULTS: We found that the Src homology 3 (SH3) domain of ßPix interacts with the proline-rich domain of Dynamin 2 (Dyn2), a large GTPase. The ßPix-Dyn2 interaction promoted lamellipodia formation, along with plasma membrane localization of membrane-type 1 matrix metalloproteinase (MT1-MMP). Furthermore, we found that Src kinase-mediated phosphorylation of the tyrosine residue at position 442 of ßPix enhanced ßPix-Dyn2 complex formation. Disruption of the ßPix-Dyn2 complex by ßPix-SH3 antibodies targeting intracellular ßPix inhibited CRC cell invasion. CONCLUSIONS: Our data indicate that spatiotemporal regulation of the Src-ßPix-Dyn2 axis is crucial for CRC cell invasion by promoting membrane dynamics and MT1-MMP recruitment into the leading edge. The development of inhibitors that disrupt the ßPix-Dyn2 complex may be a useful therapeutic strategy for CRC.


Asunto(s)
Membrana Celular/metabolismo , Neoplasias Colorrectales/metabolismo , Neoplasias Colorrectales/patología , Progresión de la Enfermedad , Dinamina II/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Secuencia de Aminoácidos , Línea Celular Tumoral , Movimiento Celular/genética , Dinamina II/química , Regulación Neoplásica de la Expresión Génica , Oro/química , Células HEK293 , Humanos , Metaloproteinasa 14 de la Matriz/metabolismo , Nanopartículas del Metal/química , Invasividad Neoplásica , Fosforilación , Fosfotirosina/metabolismo , Unión Proteica , Seudópodos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/química , Regulación hacia Arriba , Proteína de Unión al GTP rac1/metabolismo , Dominios Homologos src
3.
Am J Emerg Med ; 40: 184-187, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33243534

RESUMEN

BACKGROUND: Aconitine is well-known for its potential analgesic, anti-inflammatory, and circulation promoting effects and has been widely used as a folk medicine in South Korea. Owing to its extremely toxic nature and relatively low safety margin, intoxication is sometimes fatal. The toxic compound mainly affects the central nervous system, heart, and muscle, resulting in cardiovascular complications. PURPOSE: To determine the exact relationship between blood concentration of aconitine and clinical manifestation. BASIC PROCEDURES: The National Forensic Service (NFS) was commissioned to assist in a quantitative analysis of highly toxic aconitine and corresponding blood concentrations by analyzing the body fluids of three patients who were suspected of aconitine poisoning. MAIN FINDINGS: Aconitine blood values tested by the NFS showed that patients with a blood concentration below a certain level developed symptoms slowly and showed a high severity of clinical manifestation. There was no correlation between blood concentration and symptoms or ECG results. CONCLUSIONS: In case of suspected aconitine poisoning, an emergency care department should be visited, even with symptomatic improvement, and the patient should be monitored for at least 24 h, depending on the level of recovery and changes in ECG results.


Asunto(s)
Aconitina/sangre , Aconitina/envenenamiento , Anciano , Anciano de 80 o más Años , Electrocardiografía , Servicio de Urgencia en Hospital , Femenino , Medicina Legal , Humanos , Masculino , Persona de Mediana Edad , República de Corea
4.
BMC Biol ; 18(1): 60, 2020 06 03.
Artículo en Inglés | MEDLINE | ID: mdl-32493324

RESUMEN

BACKGROUND: Epithin/PRSS14, a type II transmembrane serine protease, is an emerging target of cancer therapy because of its critical roles in tumor progression and metastasis. In many circumstances, the protease, through its ectodomain shedding, exists as a soluble form and performs its proteolytic functions in extracellular environments increasing cellular invasiveness. The seemingly functional integrity of the soluble form raises the question of why the protease is initially made as a membrane-associated protein. RESULTS: In this report, we show that the epithin/PRSS14 intracellular domain (EICD) can be released from the membrane by the action of signal peptide peptidase-like 2b (SPPL2b) after ectodomain shedding. The EICD preferentially localizes in the nucleus and can enhance migration, invasion, and metastasis of epithelial cancer when heterologously expressed. Unbiased RNA-seq analysis and subsequent antibody arrays showed that EICD could control the gene expression of chemokines involved in cell motility, by increasing their promoter activities. Finally, bioinformatics analysis provided evidence for the clinical significance of the intramembrane proteolysis of epithin/PRSS14 by revealing that the poor survival of estrogen receptor (ER)-negative breast cancer patients with high epithin/PRSS14 expression is further worsened by high levels of SPPL2b. CONCLUSIONS: These results show that ectodomain shedding of epithin/PRSS14 can initiate a unique and synchronized bidirectional signal for cancer metastasis: extracellularly broadening proteolytic modification of the surrounding environment and intracellularly reprogramming the transcriptome for metastatic conversion. Clinically, this study also suggests that the intracellular function of epithin/PRSS14 should be considered for targeting this protease for anti-cancer treatment.


Asunto(s)
Neoplasias de la Mama/genética , Proteínas de la Membrana/genética , Proteolisis , Serina Endopeptidasas/genética , Animales , Neoplasias de la Mama/fisiopatología , Movimiento Celular , Núcleo Celular/metabolismo , Células Cultivadas , Humanos , Proteínas de la Membrana/metabolismo , Ratones , Ratones Endogámicos BALB C , Ratones Transgénicos , Serina Endopeptidasas/metabolismo
5.
PLoS One ; 15(5): e0233327, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32401784

RESUMEN

[This corrects the article DOI: 10.1371/journal.pone.0230814.].

6.
PLoS One ; 15(4): e0230814, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32251425

RESUMEN

Microtubules are a major cytoskeletal component of neurites, and the regulation of microtubule stability is essential for neurite morphogenesis. ßPix (ARHGEF7) is a guanine nucleotide exchange factor for the small GTPases Rac1 and Cdc42, which modulate the organization of actin filaments and microtubules. ßPix is expressed as alternatively spliced variants, including the ubiquitous isoform ßPix-a and the neuronal isoforms ßPix-b and ßPix-d, but the function of the neuronal isoforms remains unclear. Here, we reveal the novel role of ßPix neuronal isoforms in regulating tubulin acetylation and neurite outgrowth. At DIV4, hippocampal neurons cultured from ßPix neuronal isoform knockout (ßPix-NIKO) mice exhibit defects in neurite morphology and tubulin acetylation, a type of tubulin modification which often labels stable microtubules. Treating ßPix-NIKO neurons with paclitaxel, which stabilizes the microtubules, or reintroducing either neuronal ßPix isoform to the KO neurons overcomes the impairment in neurite morphology and tubulin acetylation, suggesting that neuronal ßPix isoforms may promote microtubule stabilization during neurite development. ßPix-NIKO neurons also exhibit lower phosphorylation levels for Stathmin1, a microtubule-destabilizing protein, at Ser16. Expressing either ßPix neuronal isoform in the ßPix-NIKO neurons restores Stathmin1 phosphorylation levels, with ßPix-d having a greater effect than ßPix-b. Furthermore, we find that the recovery of neurite length and Stathmin1 phosphorylation via ßPix-d expression requires PAK kinase activity. Taken together, our study demonstrates that ßPix-d regulates the phosphorylation of Stathmin1 in a PAK-dependent manner and that neuronal ßPix isoforms promote tubulin acetylation and neurite morphogenesis during neuronal development.


Asunto(s)
Proyección Neuronal/fisiología , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Transducción de Señal/fisiología , Estatmina/metabolismo , Tubulina (Proteína)/metabolismo , Quinasas p21 Activadas/metabolismo , Proteína de Unión al GTP rac1/metabolismo , Acetilación , Citoesqueleto de Actina/metabolismo , Animales , Proteínas de Ciclo Celular/metabolismo , Células Cultivadas , Femenino , Hipocampo/metabolismo , Hipocampo/fisiología , Masculino , Ratones , Ratones Noqueados , Microtúbulos/metabolismo , Neuritas/metabolismo , Neuritas/fisiología , Neuronas/metabolismo , Neuronas/fisiología , Fosforilación/fisiología , Isoformas de Proteínas/metabolismo , Isoformas de Proteínas/fisiología
7.
Mol Cells ; 42(8): 589-596, 2019 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-31402636

RESUMEN

ßPix is a guanine nucleotide exchange factor for the Rho family small GTPases, Rac1 and Cdc42. It is known to regulate focal adhesion dynamics and cell migration. However, the in vivo role of ßPix is currently not well understood. Here, we report the production and characterization of ßPix-KO mice. Loss of ßPix results in embryonic lethality accompanied by abnormal developmental features, such as incomplete neural tube closure, impaired axial rotation, and failure of allantoischorion fusion. We also generated ßPix-KO mouse embryonic fibroblasts (MEFs) to examine ßPix function in mouse fibroblasts. ßPix-KO MEFs exhibit decreased Rac1 activity, and defects in cell spreading and platelet-derived growth factor (PDGF)-induced ruffle formation and chemotaxis. The average size of focal adhesions is increased in ßPix-KO MEFs. Interestingly, ßPix-KO MEFs showed increased motility in random migration and rapid wound healing with elevated levels of MLC2 phosphorylation. Taken together, our data demonstrate that ßPix plays essential roles in early embryonic development, cell spreading, and cell migration in fibroblasts.


Asunto(s)
Movimiento Celular/efectos de los fármacos , Quimiotaxis/efectos de los fármacos , Embrión de Mamíferos/citología , Desarrollo Embrionario/efectos de los fármacos , Fibroblastos/citología , Factor de Crecimiento Derivado de Plaquetas/farmacología , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Animales , Bovinos , Pérdida del Embrión/patología , Fibroblastos/efectos de los fármacos , Fibroblastos/metabolismo , Adhesiones Focales/metabolismo , Humanos , Ratones Noqueados , Cadenas Ligeras de Miosina/metabolismo , Fosforilación/efectos de los fármacos , Fosfoserina/metabolismo
8.
Biochem Biophys Res Commun ; 516(4): 1204-1210, 2019 09 03.
Artículo en Inglés | MEDLINE | ID: mdl-31296385

RESUMEN

ßPix activates Rho family small GTPases, Rac1 and Cdc42 as a guanine nucleotide exchange factor. Although overexpression of ßPix in cultured neurons indicates that ßPix is involved in spine morphogenesis and synapse formation in vitro, the in vivo role of ßPix in the neuron is not well understood. Recently, we generated ßPix knockout mice that showed lethality at embryonic day 9.5. Here, we investigate the neuronal role of ßPix using ßPix heterozygous mice that are viable and fertile. ßPix heterozygous mice show decreased expression levels of ßPix proteins in various tissues including the brain. Cultured hippocampal neurons from ßPix heterozygous mice show a decrease in neurite length and complexity as well as synaptic density. Both excitatory and inhibitory synapse densities are decreased in these neurons. Golgi-staining of hippocampal tissues from the brain of these mice show reduced dendritic complexity and spine density in the hippocampal neurons. Expression levels of NMDA- and AMPA-receptor subunits and Git1 protein in hippocampal tissues are also decreased in these mice. Behaviorally, ßPix heterozygous mice exhibit impaired social interaction. Altogether, these results indicate that ßPix is required for neurite morphogenesis and synapse formation, and the reduced expression of ßPix proteins results in a defect in social behavior.


Asunto(s)
Hipocampo/patología , Neuronas/patología , Factores de Intercambio de Guanina Nucleótido Rho/genética , Animales , Células Cultivadas , Dendritas/metabolismo , Dendritas/patología , Eliminación de Gen , Heterocigoto , Hipocampo/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neuritas/metabolismo , Neuritas/patología , Neuronas/metabolismo , Conducta Social , Sinapsis/metabolismo , Sinapsis/patología
9.
J Cell Sci ; 132(5)2019 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-30683798

RESUMEN

PAK-interacting guanine nucleotide exchange factor (ßPix; also known as Arhgef7) has been implicated in many actin-based cellular processes, including spine morphogenesis in neurons. However, the molecular mechanisms by which ßPix controls spine morphology remain elusive. Previously, we have reported the expression of several alternative spliced ßPix isoforms in the brain. Here, we report a novel finding that the b isoform of ßPix (ßPix-b) mediates the regulation of spine and synapse formation. We found that ßPix-b, which is mainly expressed in neurons, enhances spine and synapse formation through preferential localization at spines. In neurons, glutamate treatment efficiently stimulates Rac1 GEF activity of ßPix-b. The glutamate stimulation also promotes Src-mediated phosphorylation of ßPix-b in both an AMPA receptor- and NMDA receptor-dependent manner. Tyrosine 598 (Y598) of ßPix-b is identified as the major Src-mediated phosphorylation site. Finally, Y598 phosphorylation of ßPix-b enhances its Rac1 GEF activity that is critical for spine and synapse formation. In conclusion, we provide a novel mechanism by which ßPix-b regulates activity-dependent spinogenesis and synaptogenesis via Src-mediated phosphorylation.


Asunto(s)
Espinas Dendríticas/metabolismo , Espinas Dendríticas/patología , Neuronas/fisiología , Factores de Intercambio de Guanina Nucleótido Rho/metabolismo , Transmisión Sináptica/fisiología , Actinas/metabolismo , Animales , Línea Celular , Células Cultivadas , Ratones , Ratones Noqueados , Morfogénesis , Neuronas/patología , Fosforilación , Receptores AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo , Factores de Intercambio de Guanina Nucleótido Rho/genética , Transducción de Señal , Familia-src Quinasas/metabolismo
10.
Forensic Sci Int ; 288: 283-290, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29793194

RESUMEN

In Korea, an increasing number of people attempt to evade military conscription by posing as mental health patients. To verify the authenticity of mental illness, there is a need to detect wide range of psychoactive agents in biological specimens of conscription candidates. In this study, we developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for simultaneous determination of 18 psychoactive agents and 6 metabolites in human plasma. The method was characterized by the use of a simple, fast and cheap protein precipitation as sample preparation, a rapid run time (11min) and a low volume of plasma sample (200µL). The analytes were monitored under the scheduled multiple reaction monitoring (sMRM) positive and negative mode using electrospray ionization (ESI). The essential validation parameters including selectivity, linearity, accuracy, precision, matrix effect and recovery were satisfactory. The limit of detection ranged from 0.0005 to 0.001µg/mL, and limit of quantitation ranged from 0.005 to 0.025µg/mL. The developed method was successfully applied to 323 actual plasma samples submitted by Korea central physical examination center of military manpower administration in 2016, and is expected to contribute to the rapid and accurate disposition of military service.


Asunto(s)
Psicotrópicos/sangre , Cromatografía Liquida , Toxicología Forense , Humanos , Límite de Detección , Personal Militar , Reproducibilidad de los Resultados , República de Corea , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en Tándem
11.
Biochem Biophys Res Commun ; 490(3): 997-1003, 2017 08 26.
Artículo en Inglés | MEDLINE | ID: mdl-28666872

RESUMEN

Ectodomain shedding regulates functions of many membrane proteins through the cleavage of their juxtamembrane region mainly by a disintegrin and metalloproteinase family proteinases. Tumor necrosis factor-alpha converting enzyme (TACE) is known to be responsible for phorbol myristate acetate (PMA)-induced shedding of various membrane proteins. How PMA regulates TACE-dependent shedding and how TACE exhibits substrate specificity without proteolysis of other membrane proteins are questionable. Here, we show that TACE can interact with an actin-binding protein, filamin, through 20th filamin repeat. We found that the interaction between TACE and filamin was increased by PMA treatment. In addition, loss of filamin or specific disruption of TACE-filamin interaction inhibited ectodomain shedding of representative TACE substrates, CD44 and amyloid protein precursor. From these data, we suggest that filamin may work as a scaffold that can recruit TACE and its substrates in a PMA-dependent manner to achieve substrate specificity for TACE.


Asunto(s)
Proteína ADAM17/metabolismo , Carcinógenos/metabolismo , Filaminas/metabolismo , Serina Endopeptidasas/metabolismo , Acetato de Tetradecanoilforbol/metabolismo , Proteína ADAM17/análisis , Línea Celular Tumoral , Filaminas/análisis , Humanos , Modelos Moleculares , Dominios Proteicos/efectos de los fármacos , Mapas de Interacción de Proteínas/efectos de los fármacos , Serina Endopeptidasas/análisis
12.
J Biol Chem ; 292(24): 9858-9864, 2017 06 16.
Artículo en Inglés | MEDLINE | ID: mdl-28487468

RESUMEN

Epigallocatechin gallate (EGCG) is the principal bioactive ingredient in green tea and has been reported to have many health benefits. EGCG influences multiple signal transduction pathways related to human diseases, including redox, inflammation, cell cycle, and cell adhesion pathways. However, the molecular mechanisms of these varying effects are unclear, limiting further development and utilization of EGCG as a pharmaceutical compound. Here, we examined the effect of EGCG on two representative transmembrane signaling receptors, integrinαIIbß3 and epidermal growth factor receptor (EGFR). We report that EGCG inhibits talin-induced integrin αIIbß3 activation, but it activates αIIbß3 in the absence of talin both in a purified system and in cells. This apparent paradox was explained by the fact that the activation state of αIIbß3 is tightly regulated by the topology of ß3 transmembrane domain (TMD); increases or decreases in TMD embedding can activate integrins. Talin increases the embedding of integrin ß3 TMD, resulting in integrin activation, whereas we observed here that EGCG decreases the embedding, thus opposing talin-induced integrin activation. In the absence of talin, EGCG decreases the TMD embedding, which can also disrupt the integrin α-ß TMD interaction, leading to integrin activation. EGCG exhibited similar paradoxical behavior in EGFR signaling. EGCG alters the topology of EGFR TMD and activates the receptor in the absence of EGF, but inhibits EGF-induced EGFR activation. Thus, this widely ingested polyphenol exhibits pleiotropic effects on transmembrane signaling by modifying the topology of TMDs.


Asunto(s)
Antioxidantes/metabolismo , Catequina/análogos & derivados , Receptores ErbB/metabolismo , Integrina beta3/metabolismo , Membrana Dobles de Lípidos/metabolismo , Modelos Moleculares , Transducción de Señal , Sustitución de Aminoácidos , Animales , Antioxidantes/química , Antioxidantes/uso terapéutico , Células CHO , Catequina/química , Catequina/metabolismo , Catequina/uso terapéutico , Cricetulus , Suplementos Dietéticos , Dimerización , Receptores ErbB/agonistas , Receptores ErbB/química , Receptores ErbB/genética , Humanos , Integrina alfa2/química , Integrina alfa2/genética , Integrina alfa2/metabolismo , Integrina beta3/química , Integrina beta3/genética , Ligandos , Membrana Dobles de Lípidos/química , Mutación , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/agonistas , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/química , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/genética , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Dominios y Motivos de Interacción de Proteínas , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/metabolismo , Talina/antagonistas & inhibidores , Talina/química , Talina/metabolismo
13.
Chem Biol Drug Des ; 90(5): 873-882, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28432753

RESUMEN

Cardiovascular disease, which is caused by unregulated platelet aggregation, is one of the main causes of deaths worldwide. Many studies have focused on natural products with antiplatelet effects as a safe alternative therapy to prevent the disease. In this context, an in-house chemical library was screened to find natural products capable of inhibiting the interaction between platelet integrin αIIbß3 and fibrinogen, which is an essential step in platelet aggregation. On the basis of the screening results, indothiazinone, an alkaloid found in microbial cultures, was identified as a potential antiplatelet agent. Specifically, indothiazinone treatment significantly inhibited the binding of fibrinogen to Chinese hamster ovary cells expressing integrin αIIbß3. It also restricted thrombin- and adenosine diphosphate-dependent spreading of human platelets on a fibrinogen matrix. More importantly, surface plasmon resonance and molecular dynamics studies suggested that indothiazinone suppressed talin-induced activation of integrin αIIbß3 presumably by inhibiting talin-integrin interaction. In conclusion, these results suggest that indothiazinone can be used as a lead compound for the development of antiplatelet drugs with a novel mode of action.


Asunto(s)
Plaquetas/efectos de los fármacos , Indoles/farmacología , Inhibidores de Agregación Plaquetaria/farmacología , Tiazoles/farmacología , Animales , Plaquetas/citología , Plaquetas/metabolismo , Células CHO , Cricetulus , Humanos , Indoles/química , Modelos Moleculares , Inhibidores de Agregación Plaquetaria/química , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Talina/metabolismo , Tiazoles/química
14.
Arterioscler Thromb Vasc Biol ; 36(7): 1406-16, 2016 07.
Artículo en Inglés | MEDLINE | ID: mdl-27199448

RESUMEN

OBJECTIVE: Angiogenesis, the process of building complex vascular structures, begins with sprout formation on preexisting blood vessels, followed by extension of the vessels through proliferation and migration of endothelial cells. Based on the potential therapeutic benefits of preventing angiogenesis in pathological conditions, many studies have focused on the mechanisms of its initiation as well as control. However, how the extension of vessels is terminated remains obscure. Thus, we investigated the negative regulation mechanism. APPROACH AND RESULTS: We report that increased intracellular calcium can induce dephosphorylation of the endothelial receptor tyrosine kinase Tie2. The calcium-mediated dephosphorylation was found to be dependent on Tie2-calmodulin interaction. The Tyr1113 residue in the C-terminal end loop of the Tie2 kinase domain was mapped and found to be required for this interaction. Moreover, mutation of this residue into Phe impaired both the Tie2-calmodulin interaction and calcium-mediated Tie2 dephosphorylation. Furthermore, expressing a mutant Tie2 incapable of binding to calmodulin or inhibiting calmodulin function in vivo causes unchecked growth of the vasculature in Xenopus. Specifically, knockdown of Tie2 in Xenopus embryo retarded the sprouting and extension of intersomitic veins. Although human Tie2 expression in the Tie2-deficient animals almost completely rescued the retardation, the Tie2(Y1113F) mutant caused overgrowth of intersomitic veins with strikingly complex and excessive branching patterns. CONCLUSIONS: We propose that the calcium/calmodulin-dependent negative regulation of Tie2 can be used as an inhibitory signal for vessel growth and branching to build proper vessel architecture during embryonic development.


Asunto(s)
Señalización del Calcio , Calmodulina/metabolismo , Embrión no Mamífero/irrigación sanguínea , Células Endoteliales de la Vena Umbilical Humana/metabolismo , Neovascularización Fisiológica , Receptor TIE-2/metabolismo , Xenopus/embriología , Animales , Células CHO , Cricetulus , Embrión no Mamífero/metabolismo , Regulación del Desarrollo de la Expresión Génica , Técnicas de Silenciamiento del Gen , Genotipo , Células HEK293 , Humanos , Mutación , Fenotipo , Fosforilación , Unión Proteica , Dominios y Motivos de Interacción de Proteínas , Receptor TIE-2/genética , Transfección , Tirosina , Xenopus/genética , Xenopus/metabolismo
15.
J Cell Sci ; 129(10): 2030-42, 2016 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-27044755

RESUMEN

Vimentin, an intermediate filament protein induced during epithelial-to-mesenchymal transition, is known to regulate cell migration and invasion. However, it is still unclear how vimentin controls such behaviors. In this study, we aimed to find a new integrin regulator by investigating the H-Ras-mediated integrin suppression mechanism. Through a proteomic screen using the integrin ß3 cytoplasmic tail protein, we found that vimentin might work as an effector of H-Ras signaling. H-Ras converted filamentous vimentin into aggregates near the nucleus, where no integrin binding can occur. In addition, an increase in the amount of vimentin filaments accessible to the integrin ß3 tail enhanced talin-induced integrin binding to its ligands by inducing integrin clustering. In contrast, the vimentin head domain, which was found to bind directly to the integrin ß3 tail and compete with endogenous vimentin filaments for integrin binding, induced nuclear accumulation of vimentin filaments and reduced the amount of integrin-ligand binding. Finally, we found that expression of the vimentin head domain can reduce cell migration and metastasis. From these data, we suggest that filamentous vimentin underneath the plasma membrane is involved in increasing integrin adhesiveness, and thus regulation of the vimentin-integrin interaction might control cell adhesion.


Asunto(s)
Adhesión Celular/genética , Citoesqueleto/metabolismo , Integrina beta3/genética , Vimentina/genética , Animales , Células CHO , Membrana Celular/genética , Membrana Celular/metabolismo , Movimiento Celular/genética , Cricetinae , Cricetulus , Citoesqueleto/genética , Transición Epitelial-Mesenquimal/genética , Humanos , Integrina beta3/metabolismo , Ligandos , Unión Proteica , Mapas de Interacción de Proteínas , Proteómica , Vimentina/metabolismo
16.
Neoplasia ; 17(6): 518-24, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-26152360

RESUMEN

c-Cbl, a RING-type ubiquitin E3 ligase, downregulates various receptor tyrosine kinases (e.g., epidermal growth factor receptor (EGFR)), leading to inhibition of cell proliferation. Moreover, patients with myeloid neoplasm frequently harbor c-Cbl mutations, implicating the role of c-Cbl as a tumor suppressor. Recently, we have shown that c-Cbl downregulates αPix-mediated cell migration and invasion, and the lack of c-Cbl in the rat C6 and human A172 glioma cells is responsible for their malignant behavior. Here, we showed that c-Cbl exon skipping occurs in the glioma cells and the brain tissues from glioblastoma patients lacking c-Cbl. This exon skipping resulted in generation of two types of c-Cbl isoforms: type I lacking exon-9 and type II lacking exon-9 and exon-10. However, the c-Cbl isoforms in the cells and tissues could not be detected as they were rapidly degraded by proteasome. Consequently, C6 and A172 cells showed sustained EGFR activation. However, no splice site mutation was found in the region from exon-7 to exon-11 of the c-Cbl gene in C6 cells and a glioblastoma tissue lacking c-Cbl. In addition, c-Cbl exon skipping could be induced when cells transfected with a c-Cbl mini-gene were grown to high density or under hypoxic stress. These results suggest that unknown alternations (e.g., mutation) of splicing machinery in C6 and A172 cells and the glioblastoma brain tissues are responsible for the deleterious exon skipping. Collectively, these findings indicate that the c-Cbl exon skipping contributes to human glioma and its malignant behavior.


Asunto(s)
Exones , Regulación Neoplásica de la Expresión Génica , Glioma/genética , Glioma/patología , Hipoxia/fisiopatología , Proteínas Proto-Oncogénicas c-cbl/genética , Animales , Western Blotting , Receptores ErbB/genética , Humanos , Inmunoprecipitación , Mutación/genética , ARN Mensajero/genética , Ratas , Reacción en Cadena en Tiempo Real de la Polimerasa , Elementos Reguladores de la Transcripción , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Células Tumorales Cultivadas
17.
J Biol Chem ; 290(37): 22759-70, 2015 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-26157139

RESUMEN

Microtubule dynamics are important for axon growth during development as well as axon regeneration after injury. We have previously identified HDAC5 as an injury-regulated tubulin deacetylase that functions at the injury site to promote axon regeneration. However, the mechanisms involved in the spatial control of HDAC5 activity remain poorly understood. Here we reveal that HDAC5 interacts with the actin binding protein filamin A via its C-terminal domain. Filamin A plays critical roles in HDAC5-dependent tubulin deacetylation because, in cells lacking filamin A, the levels of acetylated tubulin are elevated markedly. We found that nerve injury increases filamin A axonal expression in a protein synthesis-dependent manner. Reducing filamin A levels or interfering with the interaction between HDAC5 and filamin A prevents injury-induced tubulin deacetylation as well as HDAC5 localization at the injured axon tips. In addition, neurons lacking filamin A display reduced axon regeneration. Our findings suggest a model in which filamin A local translation following axon injury controls localized HDAC5 activity to promote axon regeneration.


Asunto(s)
Axones/fisiología , Filaminas/metabolismo , Histona Desacetilasas/metabolismo , Modelos Neurológicos , Regeneración , Acetilación , Animales , Células Cultivadas , Filaminas/genética , Histona Desacetilasas/genética , Ratones , Ratones Noqueados , Transporte de Proteínas/genética , Tubulina (Proteína)/genética , Tubulina (Proteína)/metabolismo
18.
Mol Oncol ; 9(2): 398-408, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25306393

RESUMEN

The synergistic interaction of two antibodies targeting the same protein could be developed as an effective anti-cancer therapy. Human epidermal growth factor receptor 2 (HER2) is overexpressed in 20-25% of breast and gastric cancer patients, and HER2-targeted antibody therapy using trastuzumab is effective in many of these patients. Nonetheless, improving therapeutic efficacy and patient survival is important, particularly in patients with HER2-positive gastric cancer. Here, we describe the development of 1E11, a HER2-targeted humanized monoclonal antibody showing increased efficacy in a highly synergistic manner in combination with trastuzumab in the HER2-overexpressing gastric cancer cell lines NCI-N87 and OE-19. The two antibodies bind to sub-domain IV of the receptor, but have non-overlapping epitopes, allowing them to simultaneously bind HER2. Treatment with 1E11 alone induced apoptosis in HER2-positive cancer cells, and this effect was enhanced by combination treatment with trastuzumab. Combination treatment with 1E11 and trastuzumab reduced the levels of total HER2 protein and those of aberrant HER2 signaling molecules including phosphorylated HER3 and EGFR. The synergistic antitumor activity of 1E11 in combination with trastuzumab indicates that it could be a novel potent therapeutic antibody for the treatment of HER2-overexpressing gastric cancers.


Asunto(s)
Anticuerpos Monoclonales Humanizados/farmacología , Anticuerpos Antineoplásicos/farmacología , Anticuerpos Neutralizantes/farmacología , Antineoplásicos/farmacología , Receptor ErbB-2/antagonistas & inhibidores , Neoplasias Gástricas/tratamiento farmacológico , Línea Celular Tumoral , Sinergismo Farmacológico , Humanos , Receptor ErbB-2/metabolismo , Neoplasias Gástricas/metabolismo , Neoplasias Gástricas/patología , Trastuzumab
19.
Biochem Biophys Res Commun ; 452(4): 1084-90, 2014 Oct 03.
Artículo en Inglés | MEDLINE | ID: mdl-25245289

RESUMEN

Epithin/PRSS14, a type II transmembrane serine protease, plays critical roles in cancer metastasis. Previously, we have reported that epithin/PRSS14 undergoes ectodomain shedding in response to phorbol myristate acetate (PMA) stimulation. In this study, we show that transforming growth factor-ß (TGF-ß) induces rapid epithin/PRSS14 shedding through receptor mediated pathway in 427.1.86 thymoma cells. Tumor necrosis factor-α converting enzyme (TACE) is responsible for this shedding. Amino acid sequence encompassing the putative shedding cleavage site of epithin/PRSS14 exhibit strong homology to the cleavage site of l-selectin, a known TACE substrate. TACE inhibitor, TAPI-0 and TACE siRNA greatly reduced TGF-ß-induced epithin/PRSS14 shedding. TGF-ß treatment induces translocation of intracellular pool of TACE to the membrane where epithin/PRSS14 resides. These findings suggest that TGF-ß induces epithin/PRSS14 shedding by mediating translocation of epithin/PRSS14 sheddase, TACE, to the membrane.


Asunto(s)
Proteínas ADAM/metabolismo , Membrana Celular/metabolismo , Células Epiteliales/metabolismo , Proteínas de la Membrana/metabolismo , Serina Endopeptidasas/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Proteína ADAM17 , Animales , Línea Celular , Ratones , Transporte de Proteínas/fisiología
20.
Am J Physiol Renal Physiol ; 306(10): F1161-70, 2014 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-24694590

RESUMEN

DW1029M is a botanical extract consisting of Morus bark and Puerariae radix, produced by Dong-Wha Pharmaceutical, for nephroprotective drug development; it has been in phase II clinical trials in Korea. In our mechanistic investigations, we found that DW1029M inhibits advanced glycation end products (AGEs), rat lens aldose reductase (RLAR), and transforming growth factor (TGF)-ß1 signaling, all of which are implicated in diabetic complications such as diabetic nephropathy and diabetic retinopathy. DW1029M inhibits AGE formation via Fe(2+) chelation. The extract contains 13 active constituents that inhibit AGE formation, 8 active constituents that inhibit RLAR activity, and 1 inhibitor of TGF-ß1 signaling. Our results suggest DW1029M protects against diabetic nephropathy via blockade of AGE formation, RLAR activity, and TGF-ß1 signaling.


Asunto(s)
Aldehído Reductasa/antagonistas & inhibidores , Productos Finales de Glicación Avanzada/antagonistas & inhibidores , Morus , Extractos Vegetales/farmacología , Pueraria , Transducción de Señal/efectos de los fármacos , Factor de Crecimiento Transformador beta1/antagonistas & inhibidores , Aldehído Reductasa/efectos de los fármacos , Aldehído Reductasa/metabolismo , Animales , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/metabolismo , Nefropatías Diabéticas/prevención & control , Retinopatía Diabética/prevención & control , Modelos Animales de Enfermedad , Femenino , Productos Finales de Glicación Avanzada/efectos de los fármacos , Productos Finales de Glicación Avanzada/metabolismo , Técnicas In Vitro , Cristalino/enzimología , Extractos Vegetales/uso terapéutico , Ratas , Ratas Sprague-Dawley , Estreptozocina/efectos adversos , Factor de Crecimiento Transformador beta1/efectos de los fármacos , Factor de Crecimiento Transformador beta1/metabolismo
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