Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Microbiol Spectr ; 11(4): e0148123, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37432124

RESUMO

Streptococcus gallolyticus subsp. gallolyticus (SGG) is an opportunistic bacterial pathogen strongly associated with colorectal cancer. Here, through comparative genomics analysis, we demonstrated that the genetic locus encoding the type VIIb secretion system (T7SSb) machinery is uniquely present in SGG in two different arrangements. SGG UCN34 carrying the most prevalent T7SSb genetic arrangement was chosen as the reference strain. To identify the effectors secreted by this secretion system, we inactivated the essC gene encoding the motor of this machinery. A comparison of the proteins secreted by UCN34 wild type and its isogenic ΔessC mutant revealed six T7SSb effector proteins, including the expected WXG effector EsxA and three LXG-containing proteins. In this work, we characterized an LXG-family toxin named herein TelE promoting the loss of membrane integrity. Seven homologs of TelE harboring a conserved glycine zipper motif at the C terminus were identified in different SGG isolates. Scanning mutagenesis of this motif showed that the glycine residue at position 470 was crucial for TelE membrane destabilization activity. TelE activity was antagonized by a small protein TipE belonging to the DUF5085 family. Overall, we report herein a unique SGG T7SSb effector exhibiting a toxic activity against nonimmune bacteria. IMPORTANCE In this study, 38 clinical isolates of Streptococcus gallolyticus subsp. gallolyticus (SGG) were sequenced and a genetic locus encoding the type VIIb secretion system (T7SSb) was found conserved and absent from 16 genomes of the closely related S. gallolyticus subsp. pasteurianus (SGP). The T7SSb is a bona fide pathogenicity island. Here, we report that the model organism SGG strain UCN34 secretes six T7SSb effectors. One of the six effectors named TelE displayed a strong toxicity when overexpressed in Escherichia coli. Our results indicate that TelE is probably a pore-forming toxin whose activity can be antagonized by a specific immunity protein named TipE. Overall, we report a unique toxin-immunity protein pair and our data expand the range of effectors secreted through T7SSb.


Assuntos
Motivos de Aminoácidos , Streptococcus gallolyticus subspecies gallolyticus , Sistemas de Secreção Tipo VII , Streptococcus gallolyticus subspecies gallolyticus/genética , Glicina
2.
Chin J Cancer Res ; 35(1): 66-80, 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36910852

RESUMO

Objective: Lung metastasis is a common and fatal complication of liver transplantation for hepatocellular carcinoma (HCC). The precise prediction of post-transplant lung metastasis in the early phase is of great value. Methods: The mRNA profiles of primary and paired lung metastatic lesions were analyzed to determine key signaling pathways. We enrolled 241 HCC patients who underwent liver transplantation from three centers. Tissue microarrays were used to evaluate the prognostic capacity of tumor necrosis factor (TNF), tumor necrosis factor receptor 1 (TNFR1), and TNFR2, particularly for post-transplant lung metastasis. Results: Comparison of primary and lung metastatic lesions revealed that the TNF-dependent signaling pathway was related to lung metastasis of HCC. The expression of TNF was degraded in comparison to that in para-tumor tissues (P<0.001). The expression of key receptors in the TNF-dependent signaling pathway, TNFR1 and TNFR2, was higher in HCC tissues than in para-tumor tissues (P<0.001). TNF and TNFR1 showed no relationship with patients' outcomes, whereas elevated TNFR2 in tumor tissue was significantly associated with worse overall survival (OS) and increased recurrence risk (5-year OS rate: 31.9% vs. 62.5%, P<0.001). Notably, elevated TNFR2 levels were also associated with an increased risk of post-transplant lung metastasis (hazard ratio: 1.146; P<0.001). Cox regression analysis revealed that TNFR2, Hangzhou criteria, age, and hepatitis B surface antigen were independent risk factors for post-transplant lung metastasis, and a novel nomogram was established accordingly. The nomogram achieved excellent prognostic efficiency (area under time-dependent receiver operating characteristic =0.755, concordance-index =0.779) and was superior to conventional models, such as the Milan criteria. Conclusions: TNFR2 is a potent prognostic biomarker for predicting post-transplant lung metastasis in patients with HCC. A nomogram incorporating TNFR2 deserves to be a helpful prognostic tool in liver transplantation for HCC.

3.
JAMA Otolaryngol Head Neck Surg ; 148(9): 862-869, 2022 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-35951318

RESUMO

Importance: Obstructive sleep apnea (OSA) is associated with a rise in serum inflammatory markers, which may be attenuated by sleep surgery. Objective: To evaluate whether sleep surgery was associated with improved levels of proinflammatory markers in adults with OSA. Data Sources: Two authors independently searched Cochrane, Embase, and PubMed databases from inception through June 14, 2022. Study Selection: Two authors searched the Cochrane, Embase, and PubMed databases for studies comparing preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery. Data Extraction and Synthesis: Data were extracted from included articles into a structured proforma. Meta-analyses of the standardized mean difference (SMD) were conducted in random-effects models. To ensure relevance to clinicians and patients, the probability of benefit and number needed to treat were calculated for outcomes that demonstrated a statistically significant effect after sleep surgery. Main Outcomes and Measures: The primary outcome was the preoperative and postoperative levels of serum biomarkers in patients undergoing sleep surgery, including C-reactive protein (CRP), glucose, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and interleukin-6 (IL-6). Data analysis was performed from April to May 2022. Results: Of the 3218 studies screened, 26 studies with 1187 patients (mean [SD] age, 42.8 [11.1] years; 932 [78.5%] men and 255 [21.5%] women) were included. Soft-tissue sleep surgery was associated with a large decrease in CRP (SMD, -0.377; 95% CI, -0.617 to -0.137), total cholesterol (SMD, -0.267; 95% CI, -0.417 to -0.116), LDL (SMD, -0.201; 95% CI, -0.344 to -0.058), IL-6 (SMD, -1.086; 95% CI, -1.952 to -0.221), tumor necrosis factor-α (SMD, -0.822; 95% CI, -1.617 to -0.027), triglyceride (SMD, -0.186; 95% CI, -0.301 to -0.071), and leptin (SMD, -0.519; 95% CI, -0.954 to -0.083) in patients with OSA. Meta-regression highlighted that increased age, higher preoperative score for cumulative sleep time percentage with oxyhemoglobin saturation less than 90% (CT90), and greater change in CT90 postoperatively were associated with a greater decrease in serum CRP levels after soft-tissue sleep surgery. A greater reduction in apnea hypopnea index (AHI) was strongly associated with a greater reduction in total cholesterol and LDL. A greater reduction in body mass index and AHI were also associated with a greater increase in HDL. Conclusions and Relevance: The findings of this systematic review and meta-analysis of 26 studies suggest that sleep surgery is associated with decreased levels of CRP, total cholesterol, LDL, triglyceride, IL-6, leptin, and TNF-α, which may improve the inflammatory and cardiometabolic profile of patients who undergo sleep surgery.


Assuntos
Doenças Cardiovasculares , Apneia Obstrutiva do Sono , Adulto , Biomarcadores , Colesterol , Feminino , Humanos , Interleucina-6 , Leptina , Masculino , Pessoa de Meia-Idade , Sono , Apneia Obstrutiva do Sono/cirurgia , Triglicerídeos
4.
Front Cardiovasc Med ; 8: 724183, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35083295

RESUMO

Deep neural networks have become the mainstream approach for analyzing and interpreting histology images. In this study, we established and validated an interpretable DNN model to assess endomyocardial biopsy (EMB) data of patients with myocardial injury. Deep learning models were used to extract features and classify EMB histopathological images of heart failure cases diagnosed with either ischemic cardiomyopathy or idiopathic dilated cardiomyopathy and non-failing cases (organ donors without a history of heart failure). We utilized the gradient-weighted class activation mapping (Grad-CAM) technique to emphasize injured regions, providing an entry point to assess the dominant morphology in the process of a comprehensive evaluation. To visualize clustered regions of interest (ROI), we utilized uniform manifold approximation and projection (UMAP) embedding for dimension reduction. We further implemented a multi-model ensemble mechanism to improve the quantitative metric (area under the receiver operating characteristic curve, AUC) to 0.985 and 0.992 on ROI-level and case-level, respectively, outperforming the achievement of 0.971 ± 0.017 and 0.981 ± 0.020 based on the sub-models. Collectively, this new methodology provides a robust and interpretive framework to explore local histopathological patterns, facilitating the automatic and high-throughput quantification of cardiac EMB analysis.

5.
Front Microbiol ; 11: 519, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32300337

RESUMO

Pseudomonas aeruginosa is an environmental microorganism that can thrive in diverse ecological niches including plants, animals, water, soil, and crude oil. It also one of the microorganism widely used in tertiary recovery of crude oil and bioremediation. However, the genomic information regarding the mechanisms of survival and adapation of this bacterium in crude oil is still limited. In this study, three Pseudomonads strains (named as IMP66, IMP67, and IMP68) isolated from crude oil were taken for whole-genome sequencing by using a hybridized PacBio and Illumina approach. The phylogeny analysis showed that the three strains were all P. aeruginosa species and clustered in clade 1, the group with PAO1 as a representitive. Subsequent comparative genomic analysis revealed a high degree of individual genomic plasticity, with a probable alkane degradation genomic island, one type I-F CRISPR-Cas system and several prophages integrated into their genomes. Nine genes encoding alkane hydroxylases (AHs) homologs were found in each strain, which might enable these strains to degrade alkane in crude oil. P. aeruginosa can produce rhamnolipids (RLs) biosurfactant to emulsify oil, which enables their survival in crude oil enviroments. Our previous report showed that IMP67 and IMP68 were high RLs producers, while IMP66 produced little RLs. Genomic analysis suggested that their RLs yield was not likely due to differences at genetic level. We then further analyzed the quorum sensing (QS) signal molecules that regulate RLs synthesis. IMP67 and IMP68 produced more N-acyl-homoserine lactones (AHLs) signal molecules than that of PAO1 and IMP66, which could explain their high RLs yield. This study provides evidence for adaptation of P. aeruginosa in crude oil and proposes the potential application of IMP67 and IMP68 in microbial-enhanced oil recovery and bioremediation.

6.
JCI Insight ; 4(8)2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-30996130

RESUMO

Zebrafish are increasingly utilized to model cardiomyopathies and regeneration. Current methods evaluating cardiac function have known limitations, fail to reliably detect focal mechanics, and are not readily feasible in zebrafish. We developed a semiautomated, open-source method - displacement analysis of myocardial mechanical deformation (DIAMOND) - for quantitative assessment of 4D segmental cardiac function. We imaged transgenic embryonic zebrafish in vivo using a light-sheet fluorescence microscopy system with 4D cardiac motion synchronization. Our method permits the derivation of a transformation matrix to quantify the time-dependent 3D displacement of segmental myocardial mass centroids. Through treatment with doxorubicin, and by chemically and genetically manipulating the myocardial injury-activated Notch signaling pathway, we used DIAMOND to demonstrate that basal ventricular segments adjacent to the atrioventricular canal display the highest 3D displacement and are also the most susceptible to doxorubicin-induced injury. Thus, DIAMOND provides biomechanical insights into in vivo segmental cardiac function scalable to high-throughput research applications.


Assuntos
Antibióticos Antineoplásicos/efeitos adversos , Cardiomiopatias/induzido quimicamente , Doxorrubicina/efeitos adversos , Ventrículos do Coração/diagnóstico por imagem , Imageamento Tridimensional/métodos , Animais , Animais Geneticamente Modificados , Cardiomiopatias/diagnóstico por imagem , Cardiomiopatias/fisiopatologia , Modelos Animais de Doenças , Ecocardiografia , Embrião não Mamífero , Estudos de Viabilidade , Ventrículos do Coração/efeitos dos fármacos , Ventrículos do Coração/fisiopatologia , Ensaios de Triagem em Larga Escala/métodos , Humanos , Contração Miocárdica/efeitos dos fármacos , Miocárdio/patologia , Neoplasias/tratamento farmacológico , Receptores Notch/metabolismo , Regeneração/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Peixe-Zebra
7.
Dev Cell ; 48(5): 617-630.e3, 2019 03 11.
Artigo em Inglês | MEDLINE | ID: mdl-30799229

RESUMO

During mammalian embryogenesis, de novo hematopoiesis occurs transiently in multiple anatomical sites including the yolk sac, dorsal aorta, and heart tube. A long-unanswered question is whether these local transient hematopoietic mechanisms are essential for embryonic growth. Here, we show that endocardial hematopoiesis is critical for cardiac valve remodeling as a source of tissue macrophages. Colony formation assay from explanted heart tubes and genetic lineage tracing with the endocardial specific Nfatc1-Cre mouse revealed that hemogenic endocardium is a de novo source of tissue macrophages in the endocardial cushion, the primordium of the cardiac valves. Surface marker characterization, gene expression profiling, and ex vivo phagocytosis assay revealed that the endocardially derived cardiac tissue macrophages play a phagocytic and antigen presenting role. Indeed, genetic ablation of endocardially derived macrophages caused severe valve malformation. Together, these data suggest that transient hemogenic activity in the endocardium is indispensable for the valvular tissue remodeling in the heart.


Assuntos
Endocárdio/metabolismo , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Valvas Cardíacas/citologia , Macrófagos/metabolismo , Animais , Embrião de Mamíferos/metabolismo , Hematopoese/fisiologia , Mesoderma/metabolismo , Camundongos Transgênicos , Fatores de Transcrição NFATC/metabolismo , Saco Vitelino
8.
Biomed Eng Online ; 17(1): 187, 2018 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-30594200

RESUMO

BACKGROUND: Optical imaging is one of the most common, low-cost imaging tools used for investigating the tumor biological behavior in vivo. This study explores the feasibility and sensitivity of a near infrared fluorescent protein mKate2 for a long-term non-invasive tumor imaging in BALB/c nude mice, by using a low-power optical imaging system. METHODS: In this study, breast cancer cell line MDA-MB-435s expressing mKate2 and MDA-MB-231 expressing a dual reporter gene firefly luciferase (fLuc)-GFP were used as cell models. Tumor cells were implanted in different animal body compartments including subcutaneous, abdominal and deep tissue area and closely monitored in real-time. A simple and low-power optical imaging system was set up to image both fluorescence and bioluminescence in live animals. RESULTS: The presence of malignant tissue was further confirmed by histopathological assay. Considering its lower exposure time and no need of substrate injection, mKate2 is considered a superior choice for subcutaneous imaging compared with fLuc. On the contrary, fLuc has shown to be a better option when monitoring the tumor in a diffusive area such as abdominal cavity. Furthermore, both reporter genes have shown good stability and sensitivity for deep tissue imaging, i.e. tumor within the liver. In addition, fLuc has shown to be an excellent method for detecting tumor cells in the lung. CONCLUSIONS: The combination of mKate2 and fLuc offers a superior choice for long-term non-invasive real-time investigation of tumor biological behavior in vivo.


Assuntos
Proteínas Luminescentes/metabolismo , Imagem Óptica/métodos , Animais , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C
9.
JCI Insight ; 3(13)2018 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-29997298

RESUMO

Hemodynamic shear force has been implicated as modulating Notch signaling-mediated cardiac trabeculation. Whether the spatiotemporal variations in wall shear stress (WSS) coordinate the initiation of trabeculation to influence ventricular contractile function remains unknown. Using light-sheet fluorescent microscopy, we reconstructed the 4D moving domain and applied computational fluid dynamics to quantify 4D WSS along the trabecular ridges and in the groves. In WT zebrafish, pulsatile shear stress developed along the trabecular ridges, with prominent endocardial Notch activity at 3 days after fertilization (dpf), and oscillatory shear stress developed in the trabecular grooves, with epicardial Notch activity at 4 dpf. Genetic manipulations were performed to reduce hematopoiesis and inhibit atrial contraction to lower WSS in synchrony with attenuation of oscillatory shear index (OSI) during ventricular development. γ-Secretase inhibitor of Notch intracellular domain (NICD) abrogated endocardial and epicardial Notch activity. Rescue with NICD mRNA restored Notch activity sequentially from the endocardium to trabecular grooves, which was corroborated by observed Notch-mediated cardiomyocyte proliferations on WT zebrafish trabeculae. We also demonstrated in vitro that a high OSI value correlated with upregulated endothelial Notch-related mRNA expression. In silico computation of energy dissipation further supports the role of trabeculation to preserve ventricular structure and contractile function. Thus, spatiotemporal variations in WSS coordinate trabecular organization for ventricular contractile function.


Assuntos
Ventrículos do Coração/embriologia , Ventrículos do Coração/crescimento & desenvolvimento , Hemodinâmica , Organogênese , Algoritmos , Animais , Animais Geneticamente Modificados , Proliferação de Células , Desenvolvimento Embrionário , Fator de Transcrição GATA1 , Regulação da Expressão Gênica , Genes erbB-2/genética , Genes erbB-2/fisiologia , Insuficiência Cardíaca , Ventrículos do Coração/diagnóstico por imagem , Simulação de Dinâmica Molecular , Miócitos Cardíacos/fisiologia , RNA Mensageiro/metabolismo , Receptor Notch1/genética , Receptor Notch1/metabolismo , Receptores Notch/genética , Transdução de Sinais , Estresse Mecânico , Peixe-Zebra/embriologia , Proteínas de Peixe-Zebra
10.
Proc Natl Acad Sci U S A ; 115(20): 5157-5162, 2018 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-29712846

RESUMO

The ribosome is one of the richest targets for antibiotics. Unfortunately, antibiotic resistance is an urgent issue in clinical practice. Several ATP-binding cassette family proteins confer resistance to ribosome-targeting antibiotics through a yet unknown mechanism. Among them, MsrE has been implicated in macrolide resistance. Here, we report the cryo-EM structure of ATP form MsrE bound to the ribosome. Unlike previously characterized ribosomal protection proteins, MsrE is shown to bind to ribosomal exit site. Our structure reveals that the domain linker forms a unique needle-like arrangement with two crossed helices connected by an extended loop projecting into the peptidyl-transferase center and the nascent peptide exit tunnel, where numerous antibiotics bind. In combination with biochemical assays, our structure provides insight into how MsrE binding leads to conformational changes, which results in the release of the drug. This mechanism appears to be universal for the ABC-F type ribosome protection proteins.


Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Proteínas de Bactérias/metabolismo , Resistência Microbiana a Medicamentos , Ribossomos/efeitos dos fármacos , Ribossomos/metabolismo , Transportadores de Cassetes de Ligação de ATP/química , Trifosfato de Adenosina/metabolismo , Proteínas de Bactérias/química , Sítios de Ligação , Cristalografia por Raios X , Modelos Moleculares , Peptidil Transferases/química , Peptidil Transferases/metabolismo , Biossíntese de Proteínas , Conformação Proteica , Ribossomos/química
11.
Antioxid Redox Signal ; 28(13): 1209-1223, 2018 05 01.
Artigo em Inglês | MEDLINE | ID: mdl-29037123

RESUMO

AIMS: Redox active ultrafine particles (UFP, d < 0.2 µm) promote vascular oxidative stress and atherosclerosis. Notch signaling is intimately involved in vascular homeostasis, in which forkhead box O1 (FOXO1) acts as a co-activator of the Notch activation complex. We elucidated the importance of FOXO1/Notch transcriptional activation complex to restore vascular regeneration after UFP exposure. RESULTS: In a zebrafish model of tail injury and repair, transgenic Tg(fli1:GFP) embryos developed vascular regeneration at 3 days post amputation (dpa), whereas UFP exposure impaired regeneration (p < 0.05, n = 20 for control, n = 28 for UFP). UFP dose dependently reduced Notch reporter activity and Notch signaling-related genes (Dll4, JAG1, JAG2, Notch1b, Hey2, Hes1; p < 0.05, n = 3). In the transgenic Tg(tp1:GFP; flk1:mCherry) embryos, UFP attenuated endothelial Notch activity at the amputation site (p < 0.05 vs. wild type [WT], n = 20). A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) inhibitor or dominant negative (DN)-Notch1b messenger RNA (mRNA) disrupted the vascular network, whereas notch intracellular cytoplasmic domain (NICD) mRNA restored the vascular network (p < 0.05 vs. WT, n = 20). UFP reduced FOXO1 expression, but not Master-mind like 1 (MAML1) or NICD (p < 0.05, n = 3). Immunoprecipitation and immunofluorescence demonstrated that UFP attenuated FOXO1-mediated NICD pull-down and FOXO1/NICD co-localization, respectively (p < 0.05, n = 3). Although FOXO1 morpholino oligonucleotides (MOs) attenuated Notch activity, FOXO1 mRNA reversed UFP-mediated reduction in Notch activity to restore vascular regeneration and blood flow (p < 0.05 vs. WT, n = 5). Innovation and Conclusion: Our findings indicate the importance of the FOXO1/Notch activation complex to restore vascular regeneration after exposure to the redox active UFP. Antioxid. Redox Signal. 28, 1209-1223.


Assuntos
Células Endoteliais/efeitos dos fármacos , Proteína Forkhead Box O1/metabolismo , Material Particulado/farmacologia , Receptores Notch/metabolismo , Regeneração/efeitos dos fármacos , Proteínas de Peixe-Zebra/metabolismo , Animais , Células Cultivadas , Células Endoteliais/metabolismo , Oxirredução , Material Particulado/administração & dosagem , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Peixe-Zebra
12.
Mol Imaging Biol ; 19(6): 847-856, 2017 12.
Artigo em Inglês | MEDLINE | ID: mdl-28315202

RESUMO

PURPOSE: Preclinical imaging offers a useful tool for monitoring cancer biological behavior and therapy in vivo without the necessity of animal surgery. The following paper describes our examination of tumor progress and anti-angiogenic therapy with Bevacizumab on colon cancer subtypes (SW480 and SW620) by using different non-invasive real-time in vivo imaging techniques. PROCEDURES: Color Doppler ultrasound imaging (CDUI) was used to observe the formation of new blood vessels; a homemade fluorescence reflectance imaging (FRI) apparatus was mainly used to test the difference in VEGFR2 expression between the tumor subtypes. Briefly, 15 Balb/c nude mice bearing subcutaneous SW480 and SW620 xenografts were randomly divided into Control and Drug groups. Bevacizumab treatment lasted for 3 weeks. All images were captured pre- and post-treatment. At the end of experiment, all mice were euthanized, and tumor tissue was collected and analyzed by immunohistochemical staining. RESULTS: Expression of VEGFR2 was found to be slightly (10 %) but significantly higher for the SW620 cells than for SW480 cells. In addition, SW620 has shown to be more vascularized than SW480 subtype. After 3-week Bevacizumab therapy, no blood vessels were found within 83 % of SW620, while it was 67 % in SW480; the increase of SW620 tumor volume post-treatment was only 3.17-fold compared with the tumor volume pre-treatment, and 4.51-fold higher in SW480. CONCLUSION: Our data suggest that SW480 and SW620 cell lines respond differently to Bevacizumab therapy in vivo. Because of higher vascularization, and subsequently higher reduction by drug of new blood vessels and tumor growth rate, xenografts derived from the metastatic SW620 cell line have a better chance of being successfully treated with Bevacizumab compared with those derived from the primary tumor SW480 cell line.


Assuntos
Bevacizumab/uso terapêutico , Neoplasias do Colo/diagnóstico por imagem , Neoplasias do Colo/tratamento farmacológico , Imagem Corporal Total , Animais , Bevacizumab/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Neoplasias do Colo/irrigação sanguínea , Neoplasias do Colo/classificação , Fluorescência , Humanos , Masculino , Camundongos Endogâmicos BALB C , Camundongos Nus , Fluxo Sanguíneo Regional , Receptor 2 de Fatores de Crescimento do Endotélio Vascular/metabolismo
13.
Open Biol ; 6(11)2016 11.
Artigo em Inglês | MEDLINE | ID: mdl-27881736

RESUMO

The host immune system offers a hostile environment with antimicrobials and reactive oxygen species (ROS) that are detrimental to bacterial pathogens, forcing them to adapt and evolve for survival. However, the contribution of oxidative stress to pathogen evolution remains elusive. Using an experimental evolution strategy, we show that exposure of the opportunistic pathogen Pseudomonas aeruginosa to sub-lethal hydrogen peroxide (H2O2) levels over 120 generations led to the emergence of pro-biofilm rough small colony variants (RSCVs), which could be abrogated by l-glutathione antioxidants. Comparative genomic analysis of the RSCVs revealed that mutations in the wspF gene, which encodes for a repressor of WspR diguanylate cyclase (DGC), were responsible for increased intracellular cyclic-di-GMP content and production of Psl exopolysaccharide. Psl provides the first line of defence against ROS and macrophages, ensuring the survival fitness of RSCVs over wild-type P. aeruginosa Our study demonstrated that ROS is an essential driving force for the selection of pro-biofilm forming pathogenic variants. Understanding the fundamental mechanism of these genotypic and phenotypic adaptations will improve treatment strategies for combating chronic infections.


Assuntos
GMP Cíclico/análogos & derivados , Peróxido de Hidrogênio/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Proteínas de Bactérias/metabolismo , Biofilmes/efeitos dos fármacos , Evolução Biológica , GMP Cíclico/metabolismo , Regulação Bacteriana da Expressão Gênica , Glutationa/farmacologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo
14.
Mol Imaging Biol ; 17(6): 811-8, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25902968

RESUMO

PURPOSE: Non-invasive real-time in vivo imaging experiments using mice as animal models have become crucial for understanding cancer development and treatment. In this study, we have developed and validated a new breast cancer cell line MDA-MB-435s that stably express a far-red fluorescence protein (mKate2) and that could serve as a highly valuable cell model for studying breast cancer detection and therapy using in vivo fluorescence imaging in nude mice. PROCEDURES: The new cell line (MDA-MB-435s-mKate2) was constructed by plasmid transfection. The stability and sensitivity of mKate2, and the cell biological activities, were tested in vitro using different experimental approaches. For its potential use in tumor growth research and drug therapy in vivo, MDA-MB-435s-mKate2 was validated using the immunocompromised Balb/c nude mice tumor model. In addition, the new cell line has been characterized as a luteinizing hormone-releasing hormone receptor (LHRHR) positive cell line. RESULTS: Firstly, MDA-MB-435s-mKate2 has shown a stable chromosomal integration of the amplified mKate2 gene and good fluorescence sensitivity for detection using a fluorescence reflectance imaging (FRI) device. Compared to its parental cell line, no significant difference in cell migration, proliferation, and clone formation was observed in vitro. Secondly, using the quantification of tumor-fluorescence surface area in live animals, we were able to monitor and detect the tumor progress or tumor inhibition rate (by Paclitaxel treatment) non-invasively and in real-time. Furthermore, MDA-MB-435s-mKate2 has been positively tested for LHRHR; these findings open the possibility to use this cell line for future studies of breast cancer therapy based on LHRH analogs in vivo. CONCLUSION: In the present research, we have successfully built the MDA-MB-435s-mKate2 cell line that can be used as a suitable cell model for breast cancer therapy and anti-cancer drug evaluation by non-invasive fluorescence imaging in mice.


Assuntos
Neoplasias da Mama/patologia , Imagem Óptica , Animais , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/terapia , Linhagem Celular Tumoral , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus
15.
J Nucl Med ; 55(8): 1375-9, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24947062

RESUMO

UNLABELLED: We developed a novel integrated quad-modality system that included 3 molecular imaging methods (PET, SPECT, and fluorescence molecular imaging [FMI]) and 1 anatomic imaging modality (CT). This system could study various biologic processes in the same animal using multiple molecular tracers. In addition to the technology development, we also discussed the optimization strategy of the imaging protocols. The performance of this system was tested, and the in vivo animal experiment showed its power to trace 3 different molecular probes in living tissues. Our results demonstrated that this system has a great potential for the preclinical study of diseases. METHODS: A prototype system integrating PET, SPECT, CT, and a charge-coupled device-based free-space FMI system has been developed. Imaging and fusion capabilities of the system were evaluated by a multimodality phantom. In addition, a mouse disease model with both tumor and inflammation was studied by this system to examine the in vivo performance. The 3 types of molecular probes-(18)F-FDG, [(99m)Tc(HYNIC-3PRGD2)(tricine)(TPPTS)] ((99m)Tc-3PRG2) (HYNIC = 6-hydrazinonicotinyl; TPPTS = trisodium triphenylphosphine-3,3',3″-trisulfonate; 3PRGD2 = PEG4-E[PEG4-c(RGDfK)]2), and 3-(triethoxysilyl) propyl-Cy7-entrapped core-cross-linked polymeric micelle (Cy7-entrapped CCPM) nanoparticles-were used to target 3 different biologic processes in the tumor caused by pulmonary adenocarcinoma A549 cells. Moreover, the strategy to optimize multimodal molecular imaging procedure was studied as well, which could significantly reduce the total imaging time. RESULTS: The imaging performance has been validated by both phantom and in vivo animal experiments. With this system and optimized imaging protocol, we successfully differentiated diseases that cannot be distinguished by a single molecular imaging modality. CONCLUSION: We developed a novel quad-modality molecular imaging system that integrated PET, SPECT, FMI, and CT imaging methods to obtain whole-body multimodality images of small animals. The imaging results demonstrated that this system provides more comprehensive information for preclinical biomedical research. With optimized imaging protocols, as well as novel molecular tracers, this quad-modality system can help in the study of the physiology mechanism at an unprecedented level.


Assuntos
Diagnóstico por Imagem/instrumentação , Adenocarcinoma/diagnóstico , Animais , Linhagem Celular Tumoral , Humanos , Neoplasias Pulmonares/diagnóstico , Camundongos , Sondas Moleculares/metabolismo , Imagens de Fantasmas
16.
Adv Mater ; 26(24): 4114-20, 2014 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-24677251

RESUMO

Fe5 C2 NPs exhibit a high contrast in magnetic resonance imaging (MRI), superior photoacoustic tomography improvements, and efficient photothermal therapy (PTT) due to their unique core/shell structure, with a magnetic core and carbon shell. By conjugating a new class of affinity proteins (ZHER2:342), they can target to tumor cells with low cytotoxicity, and kill them through laser irritation. It is also possible to ablate tumors under guidance by MRI and PTT without noticeable side effects.


Assuntos
Imageamento por Ressonância Magnética/métodos , Nanopartículas Metálicas/uso terapêutico , Neoplasias Experimentais/patologia , Neoplasias Experimentais/terapia , Técnicas Fotoacústicas/métodos , Fototerapia/métodos , Animais , Compostos Inorgânicos de Carbono/uso terapêutico , Linhagem Celular Tumoral , Compostos de Ferro/uso terapêutico , Teste de Materiais , Camundongos , Tamanho da Partícula , Resultado do Tratamento
17.
J Biophotonics ; 5(5-6): 469-76, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22232081

RESUMO

Although histological analysis serves as a gold standard to cancer diagnosis, its application on skin cancer detection is largely prohibited due to its invasive nature. To obtain both the structural and pathological information in situ, a Confocal Reflectance/Auto-Fluorescence Tomography (CRAFT) system was established to examine the skin sites in vivo with both reflectance and autofluorescence modes simultaneously. Nude mice skin with cancerous sites and normal skin sites were imaged and compared with the system. The cellular density and reflective intensity in cancerous sites reflects the structural change of the tissue. With the decay coefficient analysis, the corresponding NAD(P)H decay index for cancerous sites is 1.65-fold that of normal sites, leading to a 97.8% of sensitivity and specificity for early cancer diagnosis. The results are verified by the followed histological analysis. Therefore, CRAFT may provide a novel method for the in vivo, non-invasive diagnosis of early cancer.


Assuntos
Detecção Precoce de Câncer/métodos , Neoplasias Cutâneas/diagnóstico , Neoplasias Cutâneas/patologia , Pele/citologia , Pele/patologia , Tomografia/métodos , Animais , Feminino , Flavina-Adenina Dinucleotídeo/metabolismo , Camundongos , NAD/metabolismo , NADP/metabolismo , Pele/metabolismo , Neoplasias Cutâneas/metabolismo , Espectrometria de Fluorescência
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA