Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
1.
Heliyon ; 10(17): e37213, 2024 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-39296047

RESUMEN

Background: Meteorin (METRN) is expressed predominantly in the central nervous system (CNS), where it functions by regulating glial cell differentiation and promoting axonal elongation. Nonetheless, its function within tumors is still not well understood. In this study, we focused on investigating its expression across various cancers and delving deeper into how METRN expression correlates with prognosis and immune infiltration. Methods: We explored METRN expression patterns in pan-cancers utilizing data obtained from the UCSC Xena and TCGA. In addition, analyses of survival and clinical association were conducted for tumors where METRN could affect the prognosis. Subsequently, nomogram models were constructed for sarcoma (SARC) and prostate adenocarcinoma (PRAD) to verify METRN's prognostic value in tumors. Furthermore, we also discussed the link between METRN and immune infiltration. As far as mechanisms are concerned, functional enrichment analysis was conducted to analyze the functional components and signaling pathways involved in METRN. Results: This study found that METRN was abnormally expressed in various tumors, closely connected with the prognosis and clinical characteristics of several tumors, and had good prognostic value. Moreover, analysis of immune infiltration revealed that METRN interacts with multiple immune cells, with alterations in the immune microenvironment potentially influencing tumor prognosis. Enrichment analysis indicates that METRN may influence tumorigenesis and progression through immune-related pathways. Conclusion: To sum up, our study demonstrates that METRN can be a prospective predictive biomarker in diverse cancer types and a promising target for cancer immunotherapy for pan-cancer.

3.
BMC Womens Health ; 24(1): 380, 2024 Jul 02.
Artículo en Inglés | MEDLINE | ID: mdl-38956552

RESUMEN

BACKGROUND: The aim of this study is to assess the efficacy of a multiparametric ultrasound imaging omics model in predicting the risk of postoperative recurrence and molecular typing of breast cancer. METHODS: A retrospective analysis was conducted on 534 female patients diagnosed with breast cancer through preoperative ultrasonography and pathology, from January 2018 to June 2023 at the Affiliated Cancer Hospital of Xinjiang Medical University. Univariate analysis and multifactorial logistic regression modeling were used to identify independent risk factors associated with clinical characteristics. The PyRadiomics package was used to delineate the region of interest in selected ultrasound images and extract radiomic features. Subsequently, radiomic scores were established through Least Absolute Shrinkage and Selection Operator (LASSO) regression and Support Vector Machine (SVM) methods. The predictive performance of the model was assessed using the receiver operating characteristic (ROC) curve, and the area under the curve (AUC) was calculated. Evaluation of diagnostic efficacy and clinical practicability was conducted through calibration curves and decision curves. RESULTS: In the training set, the AUC values for the postoperative recurrence risk prediction model were 0.9489, and for the validation set, they were 0.8491. Regarding the molecular typing prediction model, the AUC values in the training set and validation set were 0.93 and 0.92 for the HER-2 overexpression phenotype, 0.94 and 0.74 for the TNBC phenotype, 1.00 and 0.97 for the luminal A phenotype, and 1.00 and 0.89 for the luminal B phenotype, respectively. Based on a comprehensive analysis of calibration and decision curves, it was established that the model exhibits strong predictive performance and clinical practicability. CONCLUSION: The use of multiparametric ultrasound imaging omics proves to be of significant value in predicting both the risk of postoperative recurrence and molecular typing in breast cancer. This non-invasive approach offers crucial guidance for the diagnosis and treatment of the condition.


Asunto(s)
Neoplasias de la Mama , Recurrencia Local de Neoplasia , Humanos , Femenino , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/cirugía , Neoplasias de la Mama/genética , Recurrencia Local de Neoplasia/diagnóstico por imagen , Recurrencia Local de Neoplasia/diagnóstico , Persona de Mediana Edad , Estudios Retrospectivos , Adulto , Medición de Riesgo/métodos , Valor Predictivo de las Pruebas , Factores de Riesgo , Ultrasonografía/métodos , Anciano , Ultrasonografía Mamaria/métodos , Curva ROC
4.
BMC Med Imaging ; 24(1): 173, 2024 Jul 12.
Artículo en Inglés | MEDLINE | ID: mdl-38997649

RESUMEN

BACKGROUND: This study aims to investigate the role of shear wave elastography (SWE) and connective tissue growth factor (CTGF) in the assessment of papillary thyroid carcinoma (PTC) prognosis. METHODS: CTGF expression was detected with immunohistochemistry. Clinical and pathological data were collected. Parameters of conventional ultrasound combined with SWE were also collected. The relationship among CTGF expression, ultrasound indicators, the elastic modulus and the clinicopathological parameters were analyzed. RESULTS: Univariate analysis showed that patients with high risk of PTC were characterized with male, Uygur ethnicity, increased expression of CTGF, convex lesions, calcified, incomplete capsule, intranodular blood flow, rear echo attenuation, cervical lymph node metastasis, lesions larger than 1 cm, psammoma bodies, advanced clinical stage, increased TSH and high value in the shear modulus (P < 0.05). Multivariate analysis demonstrated that the risk factors of high expression of CTGF according to contribution size order were irregular shape, aspect ratio ≥ 1, and increased TSH. The logistic regression model equation was Logit (P) = 1.153 + 1.055 × 1 + 0.926 × 2 + 1.190 × 3 and the Area Under Curve value of the logistic regression was calculated to be 0.850, with a 95% confidence interval of 0.817 to 0.883. CONCLUSION: SWE and CTGF are of great value in the risk assessment of PTC. The degree of fibrosis of PTC is closely related to the prognosis. The hardness of PTC lesions and the expression level of CTGF are correlated with the main indexes of conventional ultrasound differentiating benign or malignant nodules. Irregular shape, aspect ratio ≥ 1, and increased TSH are independent factors of CTGF.


Asunto(s)
Factor de Crecimiento del Tejido Conjuntivo , Diagnóstico por Imagen de Elasticidad , Cáncer Papilar Tiroideo , Neoplasias de la Tiroides , Ultrasonografía Doppler en Color , Humanos , Masculino , Diagnóstico por Imagen de Elasticidad/métodos , Factor de Crecimiento del Tejido Conjuntivo/metabolismo , Femenino , Cáncer Papilar Tiroideo/diagnóstico por imagen , Cáncer Papilar Tiroideo/patología , Cáncer Papilar Tiroideo/metabolismo , Persona de Mediana Edad , Neoplasias de la Tiroides/diagnóstico por imagen , Neoplasias de la Tiroides/metabolismo , Neoplasias de la Tiroides/patología , Medición de Riesgo , Adulto , Pronóstico , Anciano , Módulo de Elasticidad , Factores de Riesgo
6.
Clin Case Rep ; 12(4): e8761, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38601173

RESUMEN

Sarcomatoid carcinoma, a rare and aggressive subtype of bladder cancer, accounting for 0.3% of cases, is more aggressive than urothelial carcinomas. Accurate diagnosis, crucial for treatment, can be challenging. We present a characterized case of sarcomatoid carcinoma of the urinary bladder using multimodal imaging and pathology.

7.
Front Oncol ; 14: 1285511, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38500656

RESUMEN

Introduction: We aim to predict the pathological complete response (pCR) of neoadjuvant chemotherapy (NAC) in breast cancer patients by constructing a Nomogram based on radiomics models, clinicopathological features, and ultrasound features. Methods: Ultrasound images of 464 breast cancer patients undergoing NAC were retrospectively analyzed. The patients were further divided into the training cohort and the validation cohort. The radiomics signatures (RS) before NAC treatment (RS1), after 2 cycles of NAC (RS2), and the different signatures between RS2 and RS1 (Delta-RS/RS1) were obtained. LASSO regression and random forest analysis were used for feature screening and model development, respectively. The independent predictors of pCR were screened from clinicopathological features, ultrasound features, and radiomics models by using univariate and multivariate analysis. The Nomogram model was constructed based on the optimal radiomics model and clinicopathological and ultrasound features. The predictive performance was evaluated with the receiver operating characteristic (ROC) curve. Results: We found that RS2 had better predictive performance for pCR. In the validation cohort, the area under the ROC curve was 0.817 (95%CI: 0.734-0.900), which was higher than RS1 and Delta-RS/RS1. The Nomogram based on clinicopathological features, ultrasound features, and RS2 could accurately predict the pCR value, and had the area under the ROC curve of 0.897 (95%CI: 0.866-0.929) in the validation cohort. The decision curve analysis showed that the Nomogram model had certain clinical practical value. Discussion: The Nomogram based on radiomics signatures after two cycles of NAC, and clinicopathological and ultrasound features have good performance in predicting the NAC efficacy of breast cancer.

10.
Clin Case Rep ; 12(2): e8456, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-38292230

RESUMEN

Sarcomatoid hepatocellular carcinoma (SHCC) is a rare subtype of hepatocellular carcinoma characterized by abdominal pain or persistent fever with an inflammatory reaction. Here, we report a case of SHCC mimicking hepatic abscess described by not only ultrasonography but also computer tomography. SHCC is a rare subtype of hepatocellular carcinoma characterized by epithelial and mesenchymal tumor features with sarcomatoid morphology. Here, we report a case of SHCC described by ultrasonography and computer tomography as well as confirmed by pathological examination.

12.
Nat Commun ; 14(1): 1623, 2023 03 23.
Artículo en Inglés | MEDLINE | ID: mdl-36959168

RESUMEN

Kinetics of NMDA receptor (NMDAR) ion channel opening and closing contribute to their unique role in synaptic signaling. Agonist binding generates free energy to open a canonical gate at the M3 helix bundle crossing. Single channel activity is characterized by clusters, or periods of rapid opening and closing, that are separated by long silent periods. A conserved glycine in the outer most transmembrane helices, the M4 helices, regulates NMDAR function. Here we find that the GluN1 glycine mainly regulates single channel events within a cluster, whereas the GluN2 glycine mainly regulates entry and exit from clusters. Molecular dynamics simulations suggest that, whereas the GluN2 M4 (along with GluN2 pre-M1) regulates the gate at the M3 helix bundle crossing, the GluN1 glycine regulates a 'gate' at the M2 loop. Subsequent functional experiments support this interpretation. Thus, the distinct kinetics of NMDARs are mediated by two gates that are under subunit-specific regulation.


Asunto(s)
N-Metilaspartato , Receptores de N-Metil-D-Aspartato , Receptores de N-Metil-D-Aspartato/química , Activación del Canal Iónico/fisiología , Simulación de Dinámica Molecular , Glicina/metabolismo
13.
PLoS One ; 16(12): e0261138, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34932597

RESUMEN

OBJECTIVE: This study is to explore the correlation between the contrast-enhanced ultrasound (CEUS) characteristics of breast cancer and the epithelial-mesenchyme transformation (EMT). METHODS: Totally 119 patients of breast cancer underwent CEUS. Tissues in the active area were collected and subjected to the immunohistochemical detection, PT-PCR and Western blot. Correlation analysis was conducted between the clinical pathological parameters and the CEUS indicators. RESULTS: The expression levels of CD44, N-cadherin, and ß-catenin in breast cancer tissues were higher than those in adjacent tissues (P<0.05). However, the expression levels of CD24 and E-cadherin in breast cancer tissues were lower than those in adjacent tissues (P<0.05). There was no significant difference in E-cadherin mRNA and Vimentin levels between cancer and adjacent tissues (P>0.05). The expressions were up-regulated in the CSCs, with higher histological grade, lymph node metastasis, and negative estrogen receptor (ER) expression. Smaller breast tumors, with no lymph node metastasis, lower clinical stage, and positive ER expression, tended to exhibit the up-regulated epithelial phenotype. Breast tumors, with high histological grade, lymph node metastasis, high clinical staging grade, and negative ER expression, tended to exhibit the up-regulated interstitial phenotype. The peak intensity of the time-intensity curve (TIC) for the CEUS was positively correlated with the CSC marker CD44 and the interstitial phenotype marker N-cadherin. The starting time of enhancement was negatively correlated with the N-cadherin. Area under the curve was positively correlated with the expression of CD44 and N-cadherin, while negatively correlated with the epithelial phenotype marker ß-catenin. The time to peak was negatively correlated with the interstitial phenotypes Vimentin and N-cadherin, with no correlation with the E-cadherin or ß-catenin. CONCLUSION: Breast cancers show the enlarged lesions after enlargement and perfusion defect for the CEUS. The fast-in pattern, high enhancement, and high perfusion in the TIC are correlated with the CSCs and EMT expressions, suggesting poor disease prognosis.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/patología , Medios de Contraste/metabolismo , Transición Epitelial-Mesenquimal , Microcirculación , Células Madre Neoplásicas/patología , Ultrasonografía Mamaria/métodos , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/metabolismo , Femenino , Humanos , Persona de Mediana Edad , Células Madre Neoplásicas/metabolismo , Pronóstico
14.
BMC Med Imaging ; 21(1): 171, 2021 11 17.
Artículo en Inglés | MEDLINE | ID: mdl-34789199

RESUMEN

BACKGROUND: This study is to examine the feasibility of shear wave elastography (SWE) anisotropy in assessing the prognosis of breast cancer. METHODS: We enrolled 119 breast cancer patients from January 2017 to October 2019. SWE was performed before operation. Emax (maximum elasticity value), Emean (average elasticity value), Esd (standard deviation of the lesion elasticity value), Eratio (elasticity value of adipose tissue), anisotropy coefficient and difference were recorded. After operation, we collected clinical pathological data, and performed immunohistochemistry and real-time PCR tests on CD44, CD24, E-cadherin, ß-catenin, vimentin and N-cadherin. Finally, we analyzed the correlation among parameters of SWE, anisotropy and clinicopathology, and markers of CSCs (cancer stem cells) and EMT (epithelial-mesenchymal transition). RESULTS: Emax, Emean and Esd of the cross section were higher than those of the longitudinal section. Breast cancer with a higher elastic modulus was often accompanied by a hyperechoic halo, which was manifested as mixed echo and post-echo attenuation, and was accompanied by a higher BI-RADS (breast imaging reporting and data system) classification. When breast cancer had hyperechoic halo and weakened posterior echo, SWE of the lesion showed more obvious anisotropy. In addition, larger diameter of the longitudinal section indicated higher stiffness of the cross section. Correlation analysis showed that E-cadherin was negatively correlated with SWE in longitudinal section. CD44, N-cadherin, ß-catenin were positively correlated with SWE in longitudinal and cross sections. Vimentin and CD24 had no correlation with SWE parameters. CONCLUSION: SWE of breast cancer is anisotropic. The cross-sectional SWE is better than the longitudinal SWE, Emax is better than Emean, the anisotropy of SWE is better than SWE, and the anisotropy factor is better than the anisotropy difference.


Asunto(s)
Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Diagnóstico por Imagen de Elasticidad/métodos , Transición Epitelial-Mesenquimal , Células Madre Neoplásicas , Adulto , Anciano , Anciano de 80 o más Años , Anisotropía , Biomarcadores de Tumor/metabolismo , Módulo de Elasticidad , Estudios de Factibilidad , Femenino , Humanos , Persona de Mediana Edad , Pronóstico
15.
J Healthc Eng ; 2021: 8830260, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34367541

RESUMEN

This paper aimed to investigate the application of ultrasound image segmentation technology based on the back propagation neural network (BPNN) artificial intelligence algorithm in the diagnosis of breast cancer axillary lymph node metastasis, thereby providing a theoretical basis for clinical diagnosis. In this study, 90 breast cancer patients with axillary lymph node metastasis were selected as the research objects and rolled randomly into an experimental group and a control group. Besides, all of them were examined by ultrasound. The BPNN algorithm for the ultrasound image segmentation diagnosis method was applied to the patiens from the experimental group, while the control group was given routine ultrasound diagnosis. Thus, the value of this algorithm in ultrasonic diagnosis was compared and explored. The results showed that when the number of hidden layer nodes based on the BPNN artificial intelligence algorithm was 2, 3, 4, 5, 6, 7, and 8, the corresponding segmentation accuracy was 97.3%, 96.5%, 94.8%, 94.8%, and 94.1% in turn. Among them, the segmentation accuracy was the highest when the number of hidden layer nodes was 2. The correlation of independent variable bubble plot analysis showed that the presence or absence of capsules, the presence of crab feet or burrs in breast cancer lesions was critical influencing factors for the occurrence of axillary lymph node metastasis, and the standardized importance was 99.7% and 70.8%, respectively. Besides, the area under the two-dimensional receiver operating characteristic (ROC) curve of the BPNN artificial intelligence algorithm model classification was always greater than the area under the curve of manual segmentation, and the segmentation accuracy was 90.31%, 94.88%, 95.48%, 95.44%, and 97.65% in sequence. In addition, the segmentation specificity of different running times was higher than that of manual segmentation. In conclusion, the BPNN artificial intelligence algorithm had high accuracy, sensitivity, and specificity for ultrasound image segmentation, with a better segmentation effect. Therefore, it had a better diagnostic effect for breast cancer axillary lymph node metastasis.


Asunto(s)
Neoplasias de la Mama , Algoritmos , Inteligencia Artificial , Neoplasias de la Mama/diagnóstico , Femenino , Humanos , Metástasis Linfática/diagnóstico por imagen , Sensibilidad y Especificidad , Tecnología , Ultrasonografía
16.
Biochem Cell Biol ; 99(3): 277-285, 2021 06.
Artículo en Inglés | MEDLINE | ID: mdl-33043682

RESUMEN

Circular RNAs (circRNAs) are tissue-specific RNAs with a more stable structure than linear RNAs, and their association with breast cancer (BC) is poorly understood. This study examined the biological effects of circ_0000043 in the progression of BC. In this study, expression of circ_0000043 in BC tissue samples was measured using quantitative real-time polymerase chain reaction. Immunohistochemistry and Western blot were used to detect the expression of Smad family member 3 (Smad3). CCK-8, wound healing, and Transwell assays were used to assess the effect of circ_0000043 on the proliferation, migration, and invasiveness of BC cells. Moreover, the binding relationships between circ_0000043 and miR-136, and miR-136 and Smad3 were detected by dual-luciferase reporter assay. Additionally, Western blot was used to detect the expressions of markers related to epithelial-mesenchymal transition, including E-cadherin, N-cadherin, and vimentin. Our results show that the expression of circ_0000043 is up-regulated in BC tissues and cell lines. The proliferation, migration, invasiveness, and epithelial-mesenchymal transition of BC cells were significantly inhibited by knockdown of circ_0000043, and overexpression of circ_0000043 had the opposite effects. Additionally, circ_0000043 up-regulate the expression of Smad3 by sponging miR-136. In conclusion, our study demonstrates that circ_0000043 promote the progression of BC via regulating the miR-136-Smad3 axis.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/patología , Transición Epitelial-Mesenquimal , Regulación Neoplásica de la Expresión Génica , MicroARNs/genética , ARN Circular/genética , Proteína smad3/metabolismo , Apoptosis , Biomarcadores de Tumor/genética , Neoplasias de la Mama/genética , Neoplasias de la Mama/metabolismo , Movimiento Celular , Proliferación Celular , Femenino , Humanos , Persona de Mediana Edad , Invasividad Neoplásica , Pronóstico , Proteína smad3/genética , Tasa de Supervivencia , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto
17.
Biomed Res Int ; 2020: 3869538, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33282946

RESUMEN

Nonluminal breast cancer has high early metastasis and treatment resistance, and neoadjuvant chemotherapy (NAC) is needed. The presence of cancer stem cells (CSC) and epithelial-mesenchymal transition (EMT) leads to poor prognosis. This study investigated the changes in CSC markers and EMT markers after NAC in nonluminal breast cancer and their correlation with contrast-enhanced ultrasound (CEUS) features and chemotherapy efficacy. Before NAC, the range of nonluminal breast cancer on CEUS was larger than that of two-dimensional ultrasound, but after NAC, it was significantly smaller than that of two-dimensional ultrasound and closer to the postoperative pathological size. After NAC, the enlarged lesions and perfusion defects were significantly less than those before NAC. The time-intensity curve showed the characteristics of slow-in, low enhancement, and low perfusion. Nonluminal breast cancer downregulated the expression of CSC markers and EMT markers after NAC, but the epithelial phenotype of nonluminal breast cancer with good response to chemotherapy was upregulated. In nonluminal breast cancer with poor response to chemotherapy, markers of CSC and EMT were highly expressed before chemotherapy. In conclusion, CEUS is better than conventional ultrasound in estimating NAC efficacy in this mode. CEUS can also predict the prognosis of nonluminal breast cancer before NAC with the characteristics of enhanced enlargement and perfusion defects. The contrast-enhanced time-intensity curve of lesions with relatively poor blood supply may have more CSC and EMT characteristics.


Asunto(s)
Biomarcadores de Tumor/metabolismo , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/tratamiento farmacológico , Medios de Contraste/química , Transición Epitelial-Mesenquimal , Terapia Neoadyuvante , Células Madre Neoplásicas/metabolismo , Ultrasonografía Mamaria , Adulto , Anciano , Neoplasias de la Mama/genética , Neoplasias de la Mama/patología , Femenino , Regulación Neoplásica de la Expresión Génica , Humanos , Persona de Mediana Edad , Células Madre Neoplásicas/patología , Perfusión , ARN Mensajero/genética , ARN Mensajero/metabolismo , Adulto Joven
18.
Nat Commun ; 9(1): 3748, 2018 09 14.
Artículo en Inglés | MEDLINE | ID: mdl-30217972

RESUMEN

A variety of de novo and inherited missense mutations associated with neurological disorders are found in the NMDA receptor M4 transmembrane helices, which are peripheral to the pore domain in eukaryotic ionotropic glutamate receptors. Subsets of these mutations affect receptor gating with dramatic effects, including in one instance halting it, occurring at a conserved glycine near the extracellular end of M4. Functional experiments and molecular dynamic simulations of constructs with and without substitutions at this glycine indicate that it acts as a hinge, permitting the intracellular portion of the ion channel to laterally expand. This expansion stabilizes long-lived open states leading to slow deactivation and high Ca2+ permeability. Our studies provide a functional and structural framework for the effect of missense mutations on NMDARs at central synapses and highlight how the M4 segment may represent a pathway for intracellular modulation of NMDA receptor function.


Asunto(s)
Calcio/metabolismo , Receptores de N-Metil-D-Aspartato/genética , Sinapsis/metabolismo , Animales , Encefalopatías/genética , Permeabilidad de la Membrana Celular , Niño , Preescolar , Discapacidades del Desarrollo/genética , Epilepsia/genética , Glicina/genética , Células HEK293 , Humanos , Lactante , Discapacidad Intelectual/genética , Modelos Moleculares , Simulación de Dinámica Molecular , Mutación , Mutación Missense , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Conformación Proteica en Hélice alfa , Estructura Secundaria de Proteína , Ratas , Receptores AMPA/genética , Receptores AMPA/metabolismo , Receptores de N-Metil-D-Aspartato/metabolismo
19.
J Phys Chem B ; 122(35): 8351-8358, 2018 09 06.
Artículo en Inglés | MEDLINE | ID: mdl-30111105

RESUMEN

Vitamin E is an essential micronutrient. The primary function of this lipid-soluble antioxidant is to protect membrane phospholipids from oxidation. Whether vitamin E preferentially interacts with polyunsaturated phospholipids to optimize protection of the lipid species most vulnerable to oxidative attack has been an unanswered question for a long time. In this work, we compared the binding of α-tocopherol (αtoc), the form of vitamin E retained by the human body, in bilayers composed of polyunsaturated 1-stearoyl-2-docosahexaenoylphosphatidylcholine (SDPC, 18:0-22:6PC) and, as a control, monounsaturated 1-stearoyl-2-oleoylphosphatidylcholine (SOPC, 18:0-18:1PC) by umbrella sampling molecular dynamics simulations. From the potential of mean force as a function depth within the bilayer, we find that the binding energy of αtoc is less in SDPC (Δ Gbind = 16.7 ± 0.3 kcal/mol) than that in SOPC (Δ Gbind = 18.3 ± 0.4 kcal/mol). The lower value in SDPC is ascribed to the high disorder of polyunsaturated fatty acids that produces a less tightly packed arrangement. Deformation of the bilayer is observed during desorption, indicating that phosphatidylcholine (PC)-PC and αtoc-PC interactions contribute to the binding energy. Our results do not support the proposal that vitamin E interacts more favorably with polyunsaturated phospholipids.


Asunto(s)
Membrana Dobles de Lípidos/química , Fosfatidilcolinas/química , alfa-Tocoferol/química , Simulación de Dinámica Molecular , Estructura Molecular
20.
Biochim Biophys Acta Biomembr ; 1860(10): 1985-1993, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-29730243

RESUMEN

Docosahexaenoic acid (DHA, 22:6) is an n-3 polyunsaturated fatty acid (n-3 PUFA) that influences immunological, metabolic, and neurological responses through complex mechanisms. One structural mechanism by which DHA exerts its biological effects is through its ability to modify the physical organization of plasma membrane signaling assemblies known as sphingomyelin/cholesterol (SM/chol)-enriched lipid rafts. Here we studied how DHA acyl chains esterified in the sn-2 position of phosphatidylcholine (PC) regulate the formation of raft and non-raft domains in mixtures with SM and chol on differing size scales. Coarse grained molecular dynamics simulations showed that 1-palmitoyl-2-docosahexaenoylphosphatylcholine (PDPC) enhances segregation into domains more than the monounsaturated control, 1-palmitoyl-2-oleoyl-phosphatidylcholine (POPC). Solid state 2H NMR and neutron scattering experiments provided direct experimental evidence that substituting PDPC for POPC increases the size of raft-like domains on the nanoscale. Confocal imaging of giant unilamellar vesicles with a non-raft fluorescent probe revealed that POPC had no influence on phase separation in the presence of SM/chol whereas PDPC drove strong domain segregation. Finally, monolayer compression studies suggest that PDPC increases lipid-lipid immiscibility in the presence of SM/chol compared to POPC. Collectively, the data across model systems provide compelling support for the emerging model that DHA acyl chains of PC lipids tune the size of lipid rafts, which has potential implications for signaling networks that rely on the compartmentalization of proteins within and outside of rafts.


Asunto(s)
Ácidos Docosahexaenoicos/fisiología , Microdominios de Membrana/química , Rastreo Diferencial de Calorimetría/métodos , Colesterol/química , Ácidos Docosahexaenoicos/química , Membrana Dobles de Lípidos/química , Espectroscopía de Resonancia Magnética , Microdominios de Membrana/fisiología , Simulación de Dinámica Molecular , Fosfatidilcolinas/química , Fosfatidilcolinas/fisiología , Fosfatidiletanolaminas/química , Esfingomielinas/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...