Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 68
Filtrar
Más filtros

Intervalo de año de publicación
1.
EMBO J ; 42(14): e112845, 2023 07 17.
Artículo en Inglés | MEDLINE | ID: mdl-37272163

RESUMEN

The canonical autophagy pathway in mammalian cells sequesters diverse cytoplasmic cargo within the double membrane autophagosomes that eventually convert into degradative compartments via fusion with endolysosomal intermediates. Here, we report that autophagosomal membranes show permeability in cells lacking principal ATG8 proteins (mATG8s) and are unable to mature into autolysosomes. Using a combination of methods including a novel in vitro assay to measure membrane sealing, we uncovered a previously unappreciated function of mATG8s to maintain autophagosomal membranes in a sealed state. The mATG8 proteins GABARAP and LC3A bind to key ESCRT-I components contributing, along with other ESCRTs, to the integrity and imperviousness of autophagic membranes. Autophagic organelles in cells lacking mATG8s are permeant, are arrested as amphisomes, and do not progress to functional autolysosomes. Thus, autophagosomal organelles need to be maintained in a sealed state in order to become lytic autolysosomes.


Asunto(s)
Autofagia , Proteínas Asociadas a Microtúbulos , Animales , Humanos , Familia de las Proteínas 8 Relacionadas con la Autofagia/genética , Familia de las Proteínas 8 Relacionadas con la Autofagia/metabolismo , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Autofagosomas/metabolismo , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Mamíferos
2.
J Am Chem Soc ; 146(10): 7052-7062, 2024 03 13.
Artículo en Inglés | MEDLINE | ID: mdl-38427585

RESUMEN

Functional DNAs are valuable molecular tools in chemical biology and analytical chemistry but suffer from low activities due to their limited chemical functionalities. Here, we present a chemoenzymatic method for site-specific installation of diverse functional groups on DNA, and showcase the application of this method to enhance the catalytic activity of a DNA catalyst. Through chemoenzymatic introduction of distinct chemical groups, such as hydroxyl, carboxyl, and benzyl, at specific positions, we achieve significant enhancements in the catalytic activity of the RNA-cleaving deoxyribozyme 10-23. A single carboxyl modification results in a 100-fold increase, while dual modifications (carboxyl and benzyl) yield an approximately 700-fold increase in activity when an RNA cleavage reaction is catalyzed on a DNA-RNA chimeric substrate. The resulting dually modified DNA catalyst, CaBn, exhibits a kobs of 3.76 min-1 in the presence of 1 mM Mg2+ and can be employed for fluorescent imaging of intracellular magnesium ions. Molecular dynamics simulations reveal the superior capability of CaBn to recruit magnesium ions to metal-ion-binding site 2 and adopt a catalytically competent conformation. Our work provides a broadly accessible strategy for DNA functionalization with diverse chemical modifications, and CaBn offers a highly active DNA catalyst with immense potential in chemistry and biotechnology.


Asunto(s)
ADN Catalítico , ARN Catalítico , Secuencia de Bases , Magnesio , ADN Catalítico/química , ADN , ARN/química , Iones , Conformación de Ácido Nucleico , Catálisis , ARN Catalítico/metabolismo
3.
Phys Rev Lett ; 133(6): 064001, 2024 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-39178449

RESUMEN

Laser triggered and photothermally induced vapor bubbles have emerged as promising approaches to facilitate optomechanical energy conversion for numerous applications in microfluidics and nanofluidics. Here, we report an observation of spontaneously triggered periodic nucleation of plasmonic vapor bubbles near a rigid sidewall with readily tuned nucleation frequency from 0.8 kHz to over 200 kHz. The detailed collapsing process of the vapor bubbles was experimentally and numerically investigated. We find that the lateral migration of residual bubbles toward the sidewall refreshes the laser spot area, terminates the subsequent steady bubble growth, and leads to the repeatable bubble nucleation. A mathematic model regarding the Kelvin impulses was derived. It shows that the competition between the rigid boundary induced Bjerknes force and laser irradiation caused thermal Marangoni force on collapsing bubbles governs the process. The model also leads to a criterion of γζ<0.34 for repeatable bubble nucleation, where γ is the normalized distance and ζ thermal Marangoni coefficient. This study demonstrates nucleation of violent vapor bubbles at extreme high frequencies, providing an approach to remotely realize strong localized flows in microfluidics and nanofluidics.

4.
Arch Biochem Biophys ; 760: 110134, 2024 10.
Artículo en Inglés | MEDLINE | ID: mdl-39181381

RESUMEN

Skin wound is an emerging health challenge on account of the high-frequency trauma, surgery and chronic refractory ulcer. Further study on the disease biology will help to develop new effective approaches for wound healing. Here, we identified a wound-stress responsive gene, activating transcription factor 3 (ATF3), and then investigated its biological action and mechanism in wound healing. In the full-thickness skin wound model, ATF3 was found to promote fibroblast activation and collagen production, resulted in accelerated wound healing. Mechanically, ATF3 transcriptionally activated TGF-ß receptor Ⅱ via directly binding to its specific promoter motif, followed by the enhanced TGF-ß/Smad pathway in fibroblasts. Moreover, the increased ATF3 upon skin injury was partly resulted from hypoxia stimulation with Hif-1α dependent manner. Altogether, this work gives novel insights into the biology and mechanism of stress-responsive gene ATF3 in wound healing, and provides a potential therapeutic target for treatment.


Asunto(s)
Factor de Transcripción Activador 3 , Colágeno , Fibroblastos , Piel , Cicatrización de Heridas , Factor de Transcripción Activador 3/metabolismo , Factor de Transcripción Activador 3/genética , Cicatrización de Heridas/genética , Fibroblastos/metabolismo , Animales , Colágeno/metabolismo , Piel/metabolismo , Piel/lesiones , Piel/patología , Ratones , Humanos , Receptor Tipo II de Factor de Crecimiento Transformador beta/metabolismo , Receptor Tipo II de Factor de Crecimiento Transformador beta/genética , Regiones Promotoras Genéticas , Masculino , Activación Transcripcional , Transducción de Señal , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Transcripción Genética
5.
Small ; 19(49): e2302939, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37496086

RESUMEN

Microbubble generation and manipulation play critical roles in diverse applications such as microfluidic mixing, pumping, and microrobot propulsion. However, existing methods are typically limited to lateral movements on customized substrates or rely on specific liquids with particular properties or designed concentration gradients, thereby hindering their practical applications. To address this challenge, this paper presents a method that enables robust vertical manipulation of microbubbles. By focusing a resonant laser on hydrophilic silica-coated gold nanoparticle arrays immersed in water, plasmonic microbubbles are generated and detach from the substrates immediately upon cessation of laser irradiation. Using simple laser pulse control, it can achieve an adjustable size and frequency of bubble bouncing, which is governed by the movement of the three-phase contact line during surface wetting. Furthermore, it demonstrates that rising bubbles can be pulled back by laser irradiation induced thermal Marangoni flow, which is verified by particle image velocimetry measurements and numerical simulations. This study provides novel insights into flexible bubble manipulation and integration in microfluidics, with significant implications for various applications including mixing, drug delivery, and the development of soft actuators.

6.
Cancer Invest ; 39(1): 62-72, 2021 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-33258714

RESUMEN

To dissect gene expression subgroups of FOLFOX resistance colorectal cancer(CRC) and predict FOLFOX response, gene expression data of 83 stage IV CRC tumor samples (FOLFOX responder n = 42, non-responder n = 41) are used to develop a novel iterative supervised learning method IML. IML identified two mutually exclusive subgroups of CRC patients that rely on different DNA damage repair proteins and resist FOLFOX. IML was validated in two validation sets (HR = 2.6, p Value = 0.02; HR = 2.36, p value = 0.02). A subgroup of mesenchymal subtype patients benefit from FOLFOX. Different subgroups of FOLFOX nonresponders may need to be treated differently.


Asunto(s)
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Neoplasias Colorrectales/tratamiento farmacológico , Resistencia a Antineoplásicos/efectos de los fármacos , Protocolos de Quimioterapia Combinada Antineoplásica/farmacología , Femenino , Fluorouracilo/farmacología , Fluorouracilo/uso terapéutico , Humanos , Leucovorina/farmacología , Leucovorina/uso terapéutico , Masculino , Compuestos Organoplatinos/farmacología , Compuestos Organoplatinos/uso terapéutico
7.
Sensors (Basel) ; 21(19)2021 Sep 23.
Artículo en Inglés | MEDLINE | ID: mdl-34640659

RESUMEN

For an airborne passive radar with contaminated reference signals, the clutter caused by multipath (MP) signals involved in the reference channel (MP clutter) corrupts the covariance estimation in space-time adaptive processing (STAP). In order to overcome the severe STAP performance degradation caused by impure reference signals and off-grid effects, a novel MP clutter suppression method based on local search is proposed for airborne passive radar. In the proposed method, the global dictionary is constructed based on the sparse measurement model of MP clutter, and the global atoms that are most relevant to the residual are selected. Then, the local dictionary is designed iteratively, and local searches are performed to match real MP clutter points. Finally, the off-grid effects are mitigated, and the MP clutter is suppressed from all matched atoms. A range of simulations is conducted in order to demonstrate the effectiveness of the proposed method.


Asunto(s)
Algoritmos , Sistemas de Computación , Radar
8.
J Mol Cell Cardiol ; 131: 29-40, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-31004678

RESUMEN

Although cancer cells use heparanase for tumor metastasis, favourable effects of heparanase have been reported in the management of Alzheimer's disease and diabetes. Indeed, we previously established a protective function for heparanase in the acutely diabetic heart, where it conferred cardiomyocyte resistance to oxidative stress and apoptosis by provoking changes in gene expression. In this study, we tested if overexpression of heparanase can protect the heart against chemically induced or ischemia/reperfusion (I/R) injury. Transcriptomic analysis of Hep-tg hearts reveal that 240 genes related to the stress response, immune response, cell death, and development were altered in a pro-survival direction encompassing genes promoting the unfolded protein response (UPR) and autophagy, as well as those protecting against oxidative stress. The observed UPR activation was adaptive and not apoptotic, was mediated by activation of ATF6α, and when combined with mTOR inhibition, induced autophagy. Subjecting wild type (WT) mice to increasing concentrations of the ER stress inducer thapsigargin evoked a transition from adaptive to apoptotic UPR, an effect that was attenuated in Hep-tg mouse hearts. Consistent with these observations, when exposed to I/R, the infarct size and markers of apoptosis were significantly lower in the Hep-tg heart compared to WT. Finally, UPR and autophagy inhibitors reduced the protective effects of heparanase overexpression during I/R. Our data suggest that the mechanisms that underlie the role of heparanase in promoting cell survival could be uniquely beneficial to the heart by providing protection against cellular stresses, and could be useful for exploitation as a therapeutic target for the treatment of heart disease.


Asunto(s)
Glucuronidasa/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Miocardio/metabolismo , Miocitos Cardíacos/metabolismo , Sustancias Protectoras/metabolismo , Animales , Apoptosis/fisiología , Autofagia/fisiología , Supervivencia Celular/fisiología , Corazón/fisiología , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Ratas , Ratas Wistar , Tapsigargina/metabolismo , Respuesta de Proteína Desplegada/fisiología
9.
Am J Physiol Heart Circ Physiol ; 314(1): H82-H94, 2018 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-28986359

RESUMEN

In the diabetic heart, there is excessive dependence on fatty acid (FA) utilization to generate ATP. Lipoprotein lipase (LPL)-mediated hydrolysis of circulating triglycerides is suggested to be the predominant source of FA for cardiac utilization during diabetes. In the heart, the majority of LPL is synthesized in cardiomyocytes and secreted onto cell surface heparan sulfate proteoglycan (HSPG), where an endothelial cell (EC)-releasable ß-endoglycosidase, heparanase cleaves the side chains of HSPG to liberate LPL for its onward movement across the EC. EC glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) captures this released enzyme at its basolateral side and shuttles it across to its luminal side. We tested whether the diabetes-induced increase of transforming growth factor-ß (TGF-ß) can influence the myocyte and EC to help transfer LPL to the vascular lumen to generate triglyceride-FA. In response to high glucose and EC heparanase secretion, this endoglycosidase is taken up by the cardiomyocyte (Wang Y, Chiu AP, Neumaier K, Wang F, Zhang D, Hussein B, Lal N, Wan A, Liu G, Vlodavsky I, Rodrigues B. Diabetes 63: 2643-2655, 2014) to stimulate matrix metalloproteinase-9 expression and the conversion of latent to active TGF-ß. In the cardiomyocyte, TGF-ß activation of RhoA enhances actin cytoskeleton rearrangement to promote LPL trafficking and secretion onto cell surface HSPG. In the EC, TGF-ß signaling promotes mesodermal homeobox 2 translocation to the nucleus, which increases the expression of GPIHBP1, which facilitates movement of LPL to the vascular lumen. Collectively, our data suggest that in the diabetic heart, TGF-ß actions on the cardiomyocyte promotes movement of LPL, whereas its action on the EC facilitates LPL shuttling. NEW & NOTEWORTHY Endothelial cells, as first responders to hyperglycemia, release heparanase, whose subsequent uptake by cardiomyocytes amplifies matrix metalloproteinase-9 expression and activation of transforming growth factor-ß. Transforming growth factor-ß increases lipoprotein lipase secretion from cardiomyocytes and promotes mesodermal homeobox 2 to enhance glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1-dependent transfer of lipoprotein lipase across endothelial cells, mechanisms that accelerate fatty acid utilization by the diabetic heart.


Asunto(s)
Glucemia/metabolismo , Diabetes Mellitus Experimental/enzimología , Cardiomiopatías Diabéticas/enzimología , Células Endoteliales/enzimología , Metabolismo Energético , Ácidos Grasos/metabolismo , Lipoproteína Lipasa/metabolismo , Miocitos Cardíacos/enzimología , Animales , Comunicación Celular , Células Cultivadas , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/fisiopatología , Cardiomiopatías Diabéticas/sangre , Cardiomiopatías Diabéticas/fisiopatología , Glucuronidasa/metabolismo , Proteínas de Homeodominio/metabolismo , Masculino , Metaloproteinasa 9 de la Matriz/metabolismo , Proteínas Musculares/metabolismo , Ratas Wistar , Receptores de Lipoproteína/metabolismo , Transducción de Señal , Factor de Crecimiento Transformador beta/metabolismo
10.
Am J Physiol Heart Circ Physiol ; 312(6): H1163-H1175, 2017 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-28314760

RESUMEN

Vascular endothelial growth factor B (VEGFB) is highly expressed in metabolically active tissues, such as the heart and skeletal muscle, suggesting a function in maintaining oxidative metabolic and contractile function in these tissues. Multiple models of heart failure have indicated a significant drop in VEGFB. However, whether there is a role for decreased VEGFB in diabetic cardiomyopathy is currently unknown. Of the VEGFB located in cardiomyocytes, there is a substantial and readily releasable pool localized on the cell surface. The immediate response to high glucose and the secretion of endothelial heparanase is the release of this surface-bound VEGFB, which triggers signaling pathways and gene expression to influence endothelial cell (autocrine action) and cardiomyocyte (paracrine effects) survival. Under conditions of hyperglycemia, when VEGFB production is impaired, a robust increase in vascular endothelial growth factor receptor (VEGFR)-1 expression ensues as a possible mechanism to enhance or maintain VEGFB signaling. However, even with an increase in VEGFR1 after diabetes, cardiomyocytes are unable to respond to VEGFB. In addition to the loss of VEGFB production and signaling, evaluation of latent heparanase, the protein responsible for VEGFB release, also showed a significant decline in expression in whole hearts from animals with chronic or acute diabetes. Defects in these numerous VEGFB pathways were associated with an increased cell death signature in our models of diabetes. Through this bidirectional interaction between endothelial cells (which secrete heparanase) and cardiomyocytes (which release VEGFB), this growth factor could provide the diabetic heart protection against cell death and may be a critical tool to delay or prevent cardiomyopathy.NEW & NOTEWORTHY We discovered a bidirectional interaction between endothelial cells (which secrete heparanase) and cardiomyocytes [which release vascular endothelial growth factor B (VEGFB)]. VEGFB promoted cell survival through ERK and cell death gene expression. Loss of VEGFB and its downstream signaling is an early event following hyperglycemia, is sustained with disease progression, and could explain diabetic cardiomyopathy.


Asunto(s)
Apoptosis , Cardiomiopatías Diabéticas/metabolismo , Miocardio/metabolismo , Transducción de Señal , Factor B de Crecimiento Endotelial Vascular/metabolismo , Animales , Proteínas Reguladoras de la Apoptosis/genética , Proteínas Reguladoras de la Apoptosis/metabolismo , Comunicación Autocrina , Células Cultivadas , Diabetes Mellitus Experimental/inducido químicamente , Cardiomiopatías Diabéticas/inducido químicamente , Cardiomiopatías Diabéticas/genética , Cardiomiopatías Diabéticas/patología , Células Endoteliales/enzimología , Glucuronidasa/metabolismo , Masculino , Miocardio/patología , Comunicación Paracrina , Ratas Wistar , Estreptozocina , Factor B de Crecimiento Endotelial Vascular/genética , Receptor 1 de Factores de Crecimiento Endotelial Vascular/genética , Receptor 1 de Factores de Crecimiento Endotelial Vascular/metabolismo
11.
Arterioscler Thromb Vasc Biol ; 36(1): 145-55, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26586663

RESUMEN

OBJECTIVE: Lipoprotein lipase (LPL)-mediated triglyceride hydrolysis is the major source of fatty acid for cardiac energy. LPL, synthesized in cardiomyocytes, is translocated across endothelial cells (EC) by its transporter glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1). Previously, we have reported an augmentation in coronary LPL, which was linked to an increased expression of GPIHBP1 following moderate diabetes mellitus. We examined the potential mechanism by which hyperglycemia amplifies GPIHBP1. APPROACH AND RESULTS: Exposure of rat aortic EC to high glucose induced GPIHBP1 expression and amplified LPL shuttling across these cells. This effect coincided with an elevated secretion of heparanase. Incubation of EC with high glucose or latent heparanase resulted in secretion of vascular endothelial growth factor (VEGF). Primary cardiomyocytes, being a rich source of VEGF, when cocultured with EC, restored EC GPIHBP1 that is lost because of cell passaging. Furthermore, recombinant VEGF induced EC GPIHBP1 mRNA and protein expression within 24 hours, an effect that could be prevented by a VEGF neutralizing antibody. This VEGF-induced increase in GPIHBP1 was through Notch signaling that encompassed Delta-like ligand 4 augmentation and nuclear translocation of the Notch intracellular domain. Finally, cardiomyocytes from severely diabetic animals exhibiting attenuation of VEGF were unable to increase EC GPIHBP1 expression and had lower LPL activity at the vascular lumen in perfused hearts. CONCLUSION: EC, as the first responders to hyperglycemia, can release heparanase to liberate myocyte VEGF. This growth factor, by activating EC Notch signaling, is responsible for facilitating GPIHBP1-mediated translocation of LPL across EC and regulating LPL-derived fatty acid delivery to the cardiomyocytes.


Asunto(s)
Vasos Coronarios/enzimología , Diabetes Mellitus Experimental/enzimología , Células Endoteliales/enzimología , Lipoproteína Lipasa/metabolismo , Miocitos Cardíacos/metabolismo , Comunicación Paracrina , Receptores de Lipoproteína/metabolismo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Animales , Glucemia/metabolismo , Células Cultivadas , Técnicas de Cocultivo , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/genética , Metabolismo Energético , Regulación de la Expresión Génica , Glucuronidasa/metabolismo , Péptidos y Proteínas de Señalización Intracelular/metabolismo , Masculino , Proteínas de la Membrana/metabolismo , Transporte de Proteínas , ARN Mensajero/metabolismo , Ratas Wistar , Receptores de Lipoproteína/genética , Receptores Notch/metabolismo , Transducción de Señal , Factores de Tiempo
12.
Molecules ; 21(2): 173, 2016 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-26840288

RESUMEN

In previous studies, heterocyclic amines (HCAs) have been identified as carcinogenic and a risk factor for human cancer. Therefore, the present study was designed to identify bioactive natural products capable of controlling the formation of HCAs during cooking. For this purpose we have evaluated the effect of Rosa rugosa tea extract (RTE) on the formation of HCAs in ground beef patties fried at 160 °C or 220 °C. RTE is rich in phenolic compounds and capable of inhibiting the formation of free radicals. The pyrido[3,4-b]indole (norharman) and 1-methyl-9H-pyrido[3,4-b]indole (harman) contents were significantly (p < 0.05) decreased in RTE-treated patties at 220 °C. 9H-3-Amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2) and 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole acetate (Trp-P-1) were not detected at 160 °C and were statistically (p < 0.01) reduced at 220 °C compared to the control. RTE remarkably inhibited the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) at 220 °C (p < 0.001) and at 160 °C (p < 0.05). 2-Amino-9H-pyrido[2,3-b]indole (AαC) and 2-amino-3-methyl-9H-pyrido[2,3-b]-indole (MeAαC) were only detected in the control group at 160 °C but were comparatively (p > 0.05) similar in the control and treated groups at 220 °C. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), and 2-amino-3,4,8-trimethylimidazo[4,5-f]-quinoxaline (4,8-DiMeIQx) were not detected in any sample. Total HCAs were positively correlated with cooking loss. In the RTE-treated groups, 75% of the total HCAs were decreased at 160 °C and 46% at 220 °C, suggesting that RTE is effective at both temperatures and can be used during cooking at high temperatures to lessen the amount of HCAs formed.


Asunto(s)
Aminas/análisis , Compuestos Heterocíclicos/análisis , Carne/análisis , Fenoles/farmacología , Rosa/química , Aminas/química , Animales , Bovinos , Culinaria , Compuestos Heterocíclicos/química , Calor , Humanos , Extractos Vegetales/química , Extractos Vegetales/farmacología
13.
Chin J Cancer ; 34(9): 394-403, 2015 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-26111932

RESUMEN

INTRODUCTION: Multimodality therapy, including preoperative chemoradiotherapy (CRT) and total mesorectal excision (TME), has effectively reduced local recurrence rates of rectal cancer over the past decade. However, the benefits and risks of the addition of neoadjuvant CRT to surgery need to be evaluated. This study was to compare the efficacy of TME with versus without preoperative concurrent chemoradiotherapy (CCRT) involving XELOX regimen (oxaliplatin plus capecitabine) in Chinese patients with stages II and III mid/low rectal adenocarcinoma. METHODS: We randomly assigned patients to the TME group (TME without preoperative CCRT) or CCRT + TME group (TME with preoperative CCRT). The primary endpoint was disease-free survival (DFS); the secondary endpoints were overall survival (OS), local and distant recurrence, tumor response to CRT, toxicity, sphincter preservation, and surgical complications. An interim analysis of the potential inferiority of DFS in the CCRT + TME group was planned when the first 180 patients had been followed up for at least 6 months. RESULTS: A total of 94 patients in the TME group and 90 patients in the CCRT + TME group were able to be evaluated. The 3-year DFS and OS rates were 86.3 % and 91.5 % in the whole cohort, respectively. The 3-year DFS rates of the TME and CCRT + TME groups were 85.7% and 87.9 % (P = 0.766), respectively, and the 3-year OS rates were 90.7 % and 92.3 % (P = 0.855), respectively. The functional sphincter preservation rates of the TME and CCRT + TME groups were 71.3 % and 70.0 % (P = 0.849), respectively. In the TME group, 16 (17.0 %) patients were proven to have pTNM stage I disease after surgery. In the CCRT + TME group, 32 (35.6 %) patients achieved a pathologic complete response (pCR). CONCLUSIONS: Preliminary results indicated no significant differences in the DFS, OS, or functional sphincter preservation rates between the TME and CCRT + TME groups. However, preoperative CCRT with XELOX yielded a high pCR rate. Newer techniques are needed to improve the staging accuracy, and further investigation is warranted. CLINICAL TRIAL REGISTRATION NUMBER: Chi CTR-TRC-08000122.


Asunto(s)
Quimioradioterapia , Terapia Neoadyuvante , Pronóstico , Neoplasias del Recto , Adenocarcinoma , Protocolos de Quimioterapia Combinada Antineoplásica , Capecitabina , Terapia Combinada , Desoxicitidina/análogos & derivados , Supervivencia sin Enfermedad , Fluorouracilo/análogos & derivados , Humanos , Estadificación de Neoplasias , Compuestos Organoplatinos , Oxaliplatino , Oxaloacetatos , Estudios Prospectivos , Tasa de Supervivencia
14.
J Biol Chem ; 288(4): 2355-64, 2013 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-23184941

RESUMEN

The molecular basis of the lymphatic development remains largely unknown. Using zebrafish as a model, we discovered a novel role for the Ras guanine-releasing protein 1 (RasGRP1), a protein involved in Ras activation in lymphangiogenesis. Secondary lymphatic sprouts from the posterior cardinal vein give rise to thoracic duct which is the first lymphatic vessel in zebrafish. Knockdown of rasgrp1 by injecting morpholino in zebrafish embryos impaired formation of thoracic duct accompanied by pericardial and truck edema, whereas blood vessel development of the embryos was largely unaffected. In rasgrp1-knockdown embryos, the number of sprouts producing the string of parachordal lymphangioblast cells was reduced. Meanwhile the total number of the secondary sprouts was not changed. As a result, the number of venous intersegmental vessels was increased, whereas the number of lymphatic vessel was reduced at a later stage. The lymphatic developmental defects caused by rasgrp1 knockdown could be rescued by ectopic expression of a constitutively active HRas. Further analysis revealed that RasGRP1 knockdown could synergize with flt4/vegfr3 knockdown to induce defects in lymphangiogenesis. Taken together, this finding demonstrates a critical role for RasGRP1 in lymphatic development in zebrafish.


Asunto(s)
Proteínas de Unión al ADN/fisiología , Regulación del Desarrollo de la Expresión Génica , Factores de Intercambio de Guanina Nucleótido/fisiología , Sistema Linfático/embriología , Proteínas ras/metabolismo , Animales , Animales Modificados Genéticamente , Proteínas de Unión al ADN/química , Proteínas de Unión al ADN/genética , Perfilación de la Expresión Génica , Proteínas Fluorescentes Verdes/metabolismo , Factores de Intercambio de Guanina Nucleótido/genética , Hibridación in Situ , Linfangiogénesis , Vasos Linfáticos/fisiología , Neovascularización Fisiológica , Conducto Torácico/embriología , Factores de Tiempo , Factor A de Crecimiento Endotelial Vascular/metabolismo , Pez Cebra
15.
Am J Physiol Endocrinol Metab ; 306(11): E1274-83, 2014 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-24735886

RESUMEN

In diabetes, when glucose uptake and oxidation are impaired, the heart is compelled to use fatty acid (FA) almost exclusively for ATP. The vascular content of lipoprotein lipase (LPL), the rate-limiting enzyme that determines circulating triglyceride clearance, is largely responsible for this FA delivery and increases following diabetes. Glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein [GPIHBP1; a protein expressed abundantly in the heart in endothelial cells (EC)] collects LPL from the interstitial space and transfers it across ECs onto the luminal binding sites of these cells, where the enzyme is functional. We tested whether ECs respond to hyperglycemia by increasing GPIHBP1. Streptozotocin diabetes increased cardiac LPL activity and GPIHBP1 gene and protein expression. The increased LPL and GPIHBP1 were located at the capillary lumen. In vitro, passaging EC caused a loss of GPIHBP1, which could be induced on exposure to increasing concentrations of glucose. The high-glucose-induced GPIHBP1 increased LPL shuttling across EC monolayers. GPIHBP1 expression was linked to the EC content of heparanase. Moreover, active heparanase increased GPIHBP1 gene and protein expression. Both ECs and myocyte heparan sulfate proteoglycan-bound platelet-derived growth factor (PDGF) released by heparanase caused augmentation of GPIHBP1. Overall, our data suggest that this protein "ensemble" (heparanase-PDGF-GPIHBP1) cooperates in the diabetic heart to regulate FA delivery and utilization by the cardiomyocytes. Interrupting this axis may be a novel therapeutic strategy to restore metabolic equilibrium, curb lipotoxicity, and help prevent or delay heart dysfunction that is characteristic of diabetes.


Asunto(s)
Células Endoteliales/metabolismo , Hiperglucemia/metabolismo , Lipoproteína Lipasa/biosíntesis , Receptores de Lipoproteína/biosíntesis , Animales , Transporte Biológico Activo/fisiología , Western Blotting , Bovinos , Técnicas de Cocultivo , Citocinas/biosíntesis , Diabetes Mellitus Experimental/metabolismo , Técnica del Anticuerpo Fluorescente , Glucosa/farmacología , Glucuronidasa/metabolismo , Lipólisis/fisiología , Masculino , Monocitos/metabolismo , Miocitos Cardíacos/metabolismo , Factor de Crecimiento Derivado de Plaquetas/metabolismo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Ratas , Ratas Wistar , Reacción en Cadena en Tiempo Real de la Polimerasa
16.
Arterioscler Thromb Vasc Biol ; 33(12): 2830-8, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-24115032

RESUMEN

OBJECTIVE: During diabetes mellitus, coronary lipoprotein lipase increases to promote the predominant use of fatty acids. We have reported that high glucose stimulates active heparanase secretion from endothelial cells to cleave cardiomyocyte heparan sulfate and release bound lipoprotein lipase for transfer to the vascular lumen. In the current study, we examined whether heparanase also has a function to release cardiomyocyte vascular endothelial growth factor (VEGF), and whether this growth factor influences cardiomyocyte fatty acid delivery in an autocrine manner. APPROACH AND RESULTS: Acute, reversible hyperglycemia was induced in rats, and a modified Langendorff heart perfusion was used to separate the coronary perfusate from the interstitial effluent. Coronary artery endothelial cells were exposed to high glucose to generate conditioned medium, and VEGF release from isolated cardiomyocytes was tested using endothelial cell conditioned medium or purified active and latent heparanase. Autocrine signaling of myocyte-derived VEGF on cardiac metabolism was studied. High glucose promoted latent and active heparanase secretion into endothelial cell conditioned medium, an effective stimulus for releasing cardiomyocyte VEGF. Intriguingly, latent heparanase was more efficient than active heparanase in releasing VEGF from a unique cell surface pool. VEGF augmented cardiomyocyte intracellular calcium and AMP-activated protein kinase phosphorylation and increased heparin-releasable lipoprotein lipase. CONCLUSIONS: Our data suggest that the heparanase-lipoprotein lipase-VEGF axis amplifies fatty acid delivery, a rapid and adaptive mechanism that is geared to overcome the loss of glucose consumption by the diabetic heart. If prolonged, the resultant lipotoxicity could lead to cardiovascular disease in humans.


Asunto(s)
Comunicación Autocrina , Vasos Coronarios/enzimología , Células Endoteliales/enzimología , Glucuronidasa/metabolismo , Hiperglucemia/enzimología , Lipoproteína Lipasa/metabolismo , Miocitos Cardíacos/enzimología , Factor A de Crecimiento Endotelial Vascular/metabolismo , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , Glucemia/metabolismo , Calcio/metabolismo , Medios de Cultivo Condicionados/metabolismo , Diazóxido , Modelos Animales de Enfermedad , Metabolismo Energético , Activación Enzimática , Ácidos Grasos/metabolismo , Hiperglucemia/sangre , Hiperglucemia/inducido químicamente , Fosforilación , Ratas , Transducción de Señal , Factores de Tiempo
17.
ACS Omega ; 9(25): 27329-27337, 2024 Jun 25.
Artículo en Inglés | MEDLINE | ID: mdl-38947819

RESUMEN

As gas reservoir pressure decreases, edge and bottom water irregularly flow into the reservoir through storage and permeability spaces. Water influx poses a significant challenge for the development of gas reservoirs, impacting development efficiency and the ultimate recovery rate. Therefore, exploring rational optimization methods for gas well allocation is essential. This study utilizes the vertical well productivity equation considering two-phase flow and employs the net present value (NPV) to evaluate the economic benefits of gas well production. A parallel-structured genetic algorithm (GA) is developed to account for dynamic reservoir inflow, wellbore conditions, and surface facilities engineering. The new model is applied to investigate the optimal allocation of the B-21 well in the Amu Darya right bank gas reservoirs in Turkmenistan. Results indicate a match of over 90% between the cumulative gas production and water/gas ratio calculated by the proposed method and those calculated by a numerical simulation model. Compared with the traditional genetic algorithm, the new approach reduces the number of iterations to approximately 2100 (a 72.4% decrease) and significantly improves the convergence rate.

18.
Diabetes ; 73(8): 1300-1316, 2024 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-38771953

RESUMEN

In addition to controlling smooth muscle tone in coronary vessels, endothelial cells also influence subjacent cardiomyocyte growth. Because heparanase, with exclusive expression in endothelial cells, enables extracellular matrix remodeling, angiogenesis, metabolic reprogramming, and cell survival, it is conceivable that it could also encourage development of cardiac hypertrophy. Global heparanase overexpression resulted in physiologic cardiac hypertrophy, likely an outcome of HSPG clustering and activation of hypertrophic signaling. The heparanase autocrine effect of releasing neuregulin-1 could have also contributed to this overexpression. Hyperglycemia induced by streptozotocin-induced diabetes sensitized the heart to flow-induced release of heparanase and neuregulin-1. Despite this excess secretion, progression of diabetes caused significant gene expression changes related to mitochondrial metabolism and cell death that led to development of pathologic hypertrophy and heart dysfunction. Physiologic cardiac hypertrophy was also observed in rats with cardiomyocyte-specific vascular endothelial growth factor B overexpression. When perfused, hearts from these animals released significantly higher amounts of both heparanase and neuregulin-1. However, subjecting these animals to diabetes triggered robust transcriptome changes related to metabolism and a transition to pathologic hypertrophy. Our data suggest that in the absence of mechanisms that support cardiac energy generation and prevention of cell death, as seen after diabetes, there is a transition from physiologic to pathologic cardiac hypertrophy and a decline in cardiac function.


Asunto(s)
Cardiomegalia , Diabetes Mellitus Experimental , Glucuronidasa , Remodelación Ventricular , Animales , Masculino , Ratas , Cardiomegalia/metabolismo , Cardiomegalia/patología , Diabetes Mellitus Experimental/metabolismo , Glucuronidasa/metabolismo , Glucuronidasa/genética , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Neurregulina-1/metabolismo , Neurregulina-1/genética , Remodelación Ventricular/fisiología , Femenino
19.
Pathol Res Pract ; 259: 155369, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-38820928

RESUMEN

Bladder cancer is a common malignancy with a poor prognosis worldwide. Positive cofactor 4 (PC4) is widely reported to promote malignant phenotypes in various tumors. Nonetheless, the biological function and mechanism of PC4 in bladder cancer remain unclear. Here, for the first time, we report that PC4 is elevated in bladder cancer and is associated with patient survival. Moreover, PC4 deficiency obviously inhibited bladder cancer cell proliferation and metastasis by reducing the expression of genes related to cancer stemness (CD44, CD47, KLF4 and c-Myc). Through RNA-seq and experimental verification, we found that activation of the Wnt5a/ß-catenin pathway is involved in the malignant function of PC4. Mechanistically, PC4 directly interacts with Sp1 to promote Wnt5a transcription. Thus, our study furthers our understanding of the role of PC4 in cancer stemness regulation and provides a promising strategy for bladder cancer therapy.


Asunto(s)
Regulación Neoplásica de la Expresión Génica , Factor 4 Similar a Kruppel , Células Madre Neoplásicas , Neoplasias de la Vejiga Urinaria , Proteína Wnt-5a , Animales , Humanos , Ratones , beta Catenina/metabolismo , beta Catenina/genética , Línea Celular Tumoral , Proliferación Celular/genética , Progresión de la Enfermedad , Factor 4 Similar a Kruppel/metabolismo , Células Madre Neoplásicas/patología , Células Madre Neoplásicas/metabolismo , Factor de Transcripción Sp1/metabolismo , Factor de Transcripción Sp1/genética , Neoplasias de la Vejiga Urinaria/patología , Neoplasias de la Vejiga Urinaria/genética , Neoplasias de la Vejiga Urinaria/metabolismo , Vía de Señalización Wnt/fisiología , Vía de Señalización Wnt/genética , Proteína Wnt-5a/metabolismo , Proteína Wnt-5a/genética
20.
Autophagy ; 20(2): 448-450, 2024 02.
Artículo en Inglés | MEDLINE | ID: mdl-37876292

RESUMEN

ATG5 plays a pivotal role in membrane Atg8ylation, influencing downstream processes encompassing canonical autophagy and noncanonical processes. Remarkably, genetic ablation of ATG5 in myeloid cells leads to an exacerbated pathological state in murine models of tuberculosis, characterized by an early surge in mortality much more severe when compared to the depletion of other components involved in Atg8ylation or canonical autophagy. This study shows that in the absence of ATG5, but not other core canonical autophagy factors, endolysosomal organelles display a lysosomal hypersensitivity phenotype when subjected to damage. This is in part due to a compromised recruitment of ESCRT proteins to lysosomes in need of repair. Mechanistically, in the absence of ATG5, the ESCRT protein PDCD6IP/ALIX is sequestered by the alternative conjugate ATG12-ATG3, contributing to excessive exocytic processes while not being available for lysosomal repair. Specifically, this condition increases secretion of extracellular vesicles and particles, and leads to excessive degranulation in neutrophils. Our findings uncover unique functions of ATG5 outside of the autophagy and Atg8ylation paradigm. This finding is of in vivo relevance for tuberculosis pathogenesis as modeled in mice.Abbreviations: Atg5: autophagy related 5; ESCRT: endosomal sorting complex required for transport; EVPs: extracellular vesicles and particles; FPR1: formyl peptide receptor 1; LyHYP: lysosomal hypersensitivity phenotype; LysoIP: lysosome immunopurification; Mtb: Mycobacterium tuberculosis; ORF3a: open reading frame 3a protein; PDCD6IP/ALIX: programmed cell death 6 interacting protein; SARS-CoV-2: severe acute respiratory syndrome coronavirus 2, TFEB: transcription factor EB.


Asunto(s)
Mycobacterium tuberculosis , Tuberculosis , Animales , Ratones , Autofagia/fisiología , Proteína 5 Relacionada con la Autofagia/metabolismo , Tuberculosis/microbiología , Complejos de Clasificación Endosomal Requeridos para el Transporte/metabolismo , Lisosomas/metabolismo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA