Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 35
Filtrar
Más filtros

Bases de datos
País/Región como asunto
Tipo del documento
Intervalo de año de publicación
1.
Cell Mol Life Sci ; 79(1): 37, 2021 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-34971428

RESUMEN

The roles of nitric oxide (NO) and endothelial NO synthase (eNOS) in the regulation of angiogenesis are well documented. However, the involvement of eNOS in the sprouting of endothelial tip-cells at the vascular front during sprouting angiogenesis remains poorly defined. In this study, we show that downregulation of eNOS markedly inhibits VEGF-stimulated migration of endothelial cells but increases their polarization, as evidenced by the reorientation of the Golgi in migrating monolayers and by the fewer filopodia on tip cells at ends of sprouts in endothelial cell spheroids. The effect of eNOS inhibition on EC polarization was prevented in Par3-depleted cells. Importantly, downregulation of eNOS increased the expression of polarity genes, such as PARD3B, PARD6A, PARD6B, PKCΖ, TJP3, and CRB1 in endothelial cells. In retinas of eNOS knockout mice, vascular development is retarded with decreased vessel density and vascular branching. Furthermore, tip cells at the extremities of the vascular front have a marked reduction in the number of filopodia per cell and are more oriented. In a model of oxygen-induced retinopathy (OIR), eNOS deficient mice are protected during the initial vaso-obliterative phase, have reduced pathological neovascularization, and retinal endothelial tip cells have fewer filopodia. Single-cell RNA sequencing of endothelial cells from OIR retinas revealed enrichment of genes related to cell polarity in the endothelial tip-cell subtype of eNOS deficient mice. These results indicate that inhibition of eNOS alters the polarity program of endothelial cells, which increases cell polarization, regulates sprouting angiogenesis and normalizes pathological neovascularization during retinopathy.


Asunto(s)
Neovascularización Patológica , Neovascularización Fisiológica , Óxido Nítrico Sintasa de Tipo III/fisiología , Retina/metabolismo , Neovascularización Retiniana , Vasos Retinianos , Animales , Bovinos , Línea Celular , Movimiento Celular , Polaridad Celular , Células Endoteliales , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Retina/citología , Retina/patología , Neovascularización Retiniana/metabolismo , Neovascularización Retiniana/patología , Vasos Retinianos/citología , Vasos Retinianos/patología
2.
Eur J Nutr ; 60(7): 3959-3969, 2021 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-33929587

RESUMEN

BACKGROUND: Feeding supplemented mother milk during hospital stay improves neurodevelopment in preterm infants. Yet the composition of mother milk varies widely between subjects. The relationship between this variation and outcome is unknown. OBJECTIVE: To determine whether the protein content in native breast milk (BM) correlates with 2-year infant outcome. DESIGN: In a monocentric prospective observational study, LACTACOL, preterm infants born between 28 and 34 weeks of gestation, whose mothers decided to exclusively breastfeed, were enrolled during the first week of life. Samples of expressed breast milk obtained at several times of the day were pooled over a 24-h period, and such pool was used for macronutrient analysis, using mid-infrared analyzer. Age and Stages questionnaire (ASQ) was used to assess 2-year neurodevelopmental outcome. We analyzed the relationship between protein content in BM, and (i) infant neurodevelopment at 2-year (primary outcome), and (ii) growth until 2-year (secondary outcome). RESULTS: 138 infants were enrolled. The main analysis concerned 130 infants (including 40 twin infants) and 110 mothers with BM samples collected at week 3 after birth. Native BM samples were ranked in three tertiles of protein content (g/100 ml): 0.91 ± 0.09 (lower), 1.14 ± 0.05 (middle) and 1.40 ± 0.15 (upper); 48, 47 and 35 infants were ranked, respectively, in these three tertiles. Infants in the upper tertile were more often singleton (P = 0.012) and were born with lower birth weight and head circumference Z-scores (P = 0.005 and 0.002, respectively). Differences in weight and head circumference were no longer observed at 2-year. ASQ score at age 2 did not differ between the three tertiles (P = 0.780). Sensitivity analyses with imputations, including all 138 infants, confirmed the main analysis as well as analyses based on fortified BM as exposure. CONCLUSIONS: Protein content of BM (native or fortified) is not associated with preterm infant neurodevelopment at 2-year. Higher protein content was associated with a lower birth weight.


Asunto(s)
Proteínas de la Leche , Leche Humana , Preescolar , Femenino , Alimentos Fortificados , Humanos , Lactante , Fórmulas Infantiles , Fenómenos Fisiológicos Nutricionales del Lactante , Recién Nacido , Recien Nacido Prematuro , Aumento de Peso
3.
Am J Med Genet A ; 176(7): 1614-1617, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29704302

RESUMEN

Ankyloglossia is a congenital oral anomaly characterized by the presence of a hypertrophic and short lingual frenulum. Mutations in the gene encoding the transcription factor TBX22 have been involved in isolated ankyloglossia and X-linked cleft palate. The knockout of Lgr5 in mice results in ankyloglossia. Here, we report a five-generation family including patients with severe ankyloglossia and missing lower central incisors. Two members of this family also exhibited congenital anorectal malformations. In this report, male-to-male transmission was in favor of an autosomal dominant inheritance, which allowed us to exclude the X-linked TBX22 gene. Linkage analysis using short tandem repeat markers located in the vicinity of LGR5 excluded this gene as a potential candidate. These results indicate genetic heterogeneity for ankyloglossia. Further investigations with additional families are required in order to identify novel candidate genes.


Asunto(s)
Anquiloglosia/patología , Genes Dominantes , Anomalías Dentarias/patología , Anquiloglosia/genética , Femenino , Genes Ligados a X , Humanos , Recién Nacido , Masculino , Mutación , Linaje , Fenotipo , Anomalías Dentarias/genética
5.
Bull Acad Natl Med ; 200(1): 81-90, 2016 Jan.
Artículo en Inglés, Francés | MEDLINE | ID: mdl-29889415

RESUMEN

Diagnostic of early neonatal infection remains a serious challenge. Since clinical symptoms and biological markers are neither sensitive nor specific, a lot of newborns suspected of infection, undergo biological analysis and empirical antibiotic treatment awaiting bacteriological results. However the prevalence of the disease has dramatically decreased since the last twenty years, subsequently to the generalization of the per partum antibioprophylaxis strategy. Because the possible deleterious effects of neonatal antibiotic treatment are well described now, it appears very urgent to restrict their use to the infected newborns only. Recent studies underline the benefit of using procalcitonin (PCT) to diferentiate virai infections of bacterial infections. PCT in blood cord could become a new and efficient marker to help neonatologists taking care of infection-suspected newborns. An evidence based approach is necessary, combining anamnestic, clinical and biological data as PCT to identify the very low risk newborns population and to limit the neonatal antibiotic prescriptions.


Asunto(s)
Antibacterianos/uso terapéutico , Infecciones Bacterianas/diagnóstico , Infecciones Bacterianas/tratamiento farmacológico , Calcitonina/sangre , Sangre Fetal , Algoritmos , Biomarcadores/sangre , Diagnóstico Precoz , Humanos , Prescripción Inadecuada/prevención & control , Recién Nacido
6.
Anal Bioanal Chem ; 407(9): 2485-97, 2015 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-25627788

RESUMEN

Bisphenol A (BPA) is an industrial chemical widely used in the production of polycarbonate and epoxy resins. Identified as an endocrine-disrupting chemical (EDC), BPA is a matter of existing or ongoing restrictive regulations and then is increasingly being replaced by other analogues used as BPA's substitutes. Human biomonitoring studies focusing on both BPA and emerging related analogues consequently appear as a requirement either for documenting the efficiency of regulatory actions toward BPA and for fuelling incoming risk assessment studies toward BPA's substitutes. In particular, the increasing concern about the late effects consecutive to early exposures naturally identify human breast milk as a target biological matrix of interest for priority exposure assessment focused on critical sub-populations such as pregnant women, fetuses, and/or newborns. In this context, an accurate and sensitive analytical method based on gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) was developed for the quantification of 18 "BPA-like" compounds in breast milk samples at trace levels (<0.05 µg kg(-1)). The method includes a preliminary protein precipitation step followed by two successive solid-phase extraction (SPE) stages. Quantification of the targeted compounds was achieved according to the isotopic dilution method using (13)C12-BPA as internal standard. The method was validated according to current EU guidelines and criteria. Linearity (R (2)) was better than 0.99 for each molecule within the concentration range 0-5 µg kg(-1). The detection and quantification limits ranged from 0.001 to 0.030 µg kg(-1) and from 0.002 to 0.050 µg kg(-1), respectively. The analytical method was successfully applied to the first set of human breast milk samples (n = 30) originating from French women in the Region Pays-de-la-Loire. The measured levels of BPA were found in the

Asunto(s)
Compuestos de Bencidrilo/química , Cromatografía de Gases y Espectrometría de Masas/métodos , Leche Humana/química , Fenoles/química , Espectrometría de Masas en Tándem/métodos , Femenino , Humanos , Estructura Molecular , Embarazo
7.
Rev Prat ; 65(5): 631-8, 2015 May.
Artículo en Francés | MEDLINE | ID: mdl-26165097

RESUMEN

The first weeks of life are a period of great immaturity and vulnerability. While pathologies and their semiology are very specific in this period, doctors must quickly identify therapeutic emergencies but also reassure parents when symptoms are physiological for age. Jaundice, baby crying, fever or breastfeeding constitute various medical challenges for the primary care physician, especially after birth; in an area of early back home.


Asunto(s)
Enfermedad Crítica , Urgencias Médicas , Recién Nacido , Lactancia Materna , Enfermedad Crítica/epidemiología , Enfermedad Crítica/terapia , Llanto , Fiebre/congénito , Fiebre/terapia , Humanos , Entrevistas como Asunto , Padres
8.
J Biol Chem ; 288(7): 4957-69, 2013 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-23266828

RESUMEN

Maintaining cell cohesiveness within tissues requires that intercellular adhesions develop sufficient strength to support traction forces applied by myosin motors and by neighboring cells. Cadherins are transmembrane receptors that mediate intercellular adhesion. The cadherin cytoplasmic domain recruits several partners, including catenins and vinculin, at sites of cell-cell adhesion. Our study used force measurements to address the role of αE-catenin and vinculin in the regulation of the strength of E-cadherin-based adhesion. αE-catenin-deficient cells display only weak aggregation and fail to strengthen intercellular adhesion over time, a process rescued by the expression of αE-catenin or chimeric E-cadherin·αE-catenins, including a chimera lacking the αE-catenin dimerization domain. Interestingly, an αE-catenin mutant lacking the modulation and actin-binding domains restores cadherin-dependent cell-cell contacts but cannot strengthen intercellular adhesion. The expression of αE-catenin mutated in its vinculin-binding site is defective in its ability to rescue cadherin-based adhesion strength in cells lacking αE-catenin. Vinculin depletion or the overexpression of the αE-catenin modulation domain strongly decreases E-cadherin-mediated adhesion strength. This supports the notion that both molecules are required for intercellular contact maturation. Furthermore, stretching of cell doublets increases vinculin recruitment and α18 anti-αE-catenin conformational epitope immunostaining at cell-cell contacts. Taken together, our results indicate that αE-catenin and vinculin cooperatively support intercellular adhesion strengthening, probably via a mechanoresponsive link between the E-cadherin·ß-catenin complexes and the underlying actin cytoskeleton.


Asunto(s)
Cadherinas/metabolismo , Regulación de la Expresión Génica , Vinculina/metabolismo , alfa Catenina/metabolismo , Actinas/metabolismo , Animales , Adhesión Celular , Proteínas del Citoesqueleto/metabolismo , Citoesqueleto/metabolismo , Eliminación de Gen , Ratones , Microscopía Fluorescente/métodos , Modelos Biológicos , Modelos Genéticos , Mutación , Unión Proteica , Factores de Tiempo
9.
J Biol Chem ; 287(39): 32940-52, 2012 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-22846995

RESUMEN

Galectin-3 binding to cell surface glycoproteins, including branched N-glycans generated by N-acetylglucosaminyltransferase V (Mgat5) activity, forms a multivalent, heterogeneous, and dynamic lattice. This lattice has been shown to regulate integrin and receptor tyrosine kinase signaling promoting tumor cell migration. N-cadherin is a homotypic cell-cell adhesion receptor commonly overexpressed in tumor cells that contributes to cell motility. Here we show that galectin-3 and N-cadherin interact and colocalize with the lipid raft marker GM1 ganglioside in cell-cell junctions of mammary epithelial cancer cells. Disruption of the lattice by deletion of Mgat5, siRNA depletion of galectin-3, or competitive inhibition with lactose stabilizes cell-cell junctions. It also reduces, in a p120-catenin-dependent manner, the dynamic pool of junctional N-cadherin. Proteomic analysis of detergent-resistant membranes (DRMs) revealed that the galectin lattice opposes entry of many proteins into DRM rafts. N-cadherin and catenins are present in DRMs; however, their DRM distribution is not significantly affected by lattice disruption. Galectin lattice integrity increases the mobile fraction of the raft marker, GM1 ganglioside binding cholera toxin B subunit Ctb, at cell-cell contacts in a p120-catenin-independent manner, but does not affect the mobility of either Ctb-labeled GM1 or GFP-coupled N-cadherin in nonjunctional regions. Our results suggest that the galectin lattice independently enhances lateral molecular diffusion by direct interaction with specific glycoconjugates within the adherens junction. By promoting exchange between raft and non-raft microdomains as well as molecular dynamics within junction-specific raft microdomains, the lattice may enhance turnover of N-cadherin and other glycoconjugates that determine junctional stability and rates of cell migration.


Asunto(s)
Antígenos CD/metabolismo , Neoplasias de la Mama/metabolismo , Cadherinas/metabolismo , Galectina 3/metabolismo , Gangliósidos/metabolismo , Uniones Intercelulares/metabolismo , Neoplasias Mamarias Animales/metabolismo , Microdominios de Membrana/metabolismo , Proteínas de Neoplasias/metabolismo , Animales , Antígenos CD/genética , Neoplasias de la Mama/genética , Cadherinas/genética , Línea Celular Tumoral , Movimiento Celular/genética , Femenino , Galectina 3/genética , Gangliósidos/genética , Humanos , Uniones Intercelulares/genética , Neoplasias Mamarias Animales/genética , Microdominios de Membrana/genética , Ratones , Proteínas de Neoplasias/genética , Transporte de Proteínas/genética
10.
Mol Cell Proteomics ; 10(10): M110.007146, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21753190

RESUMEN

Caveolae, a class of cholesterol-rich lipid rafts, are smooth invaginations of the plasma membrane whose formation in nonmuscle cells requires caveolin-1 (Cav1). The recent demonstration that Cav1-associated cavin proteins, in particular PTRF/cavin-1, are also required for caveolae formation supports a functional role for Cav1 independently of caveolae. In tumor cells deficient for Golgi ß-1,6N-acetylglucosaminyltransferase V (Mgat5), reduced Cav1 expression is associated not with caveolae but with oligomerized Cav1 domains, or scaffolds, that functionally regulate receptor signaling and raft-dependent endocytosis. Using subdiffraction-limit microscopy, we show that Cav1 scaffolds are homogenous subdiffraction-limit sized structures whose size distribution differs from that of Cav1 in caveolae expressing cells. These cell lines displaying differing Cav1/caveolae phenotypes are effective tools for probing the structure and composition of caveolae. Using stable isotope labeling by amino acids in cell culture, we are able to quantitatively distinguish the composition of caveolae from the background of detergent-resistant membrane proteins and show that the presence of caveolae enriches the protein composition of detergent-resistant membrane, including the recruitment of multiple heterotrimeric G-protein subunits. These data were further supported by analysis of immuno-isolated Cav1 domains and of methyl-ß-cyclodextrin-disrupted detergent-resistant membrane. Our data show that loss of caveolae results in a dramatic change to the membrane raft proteome and that this change is independent of Cav1 expression. The proteomics data, in combination with subdiffraction-limit microscopy, indicates that noncaveolar Cav1 domains, or scaffolds are structurally and functionally distinct from caveolae and differentially impact on the molecular composition of lipid rafts.


Asunto(s)
Caveolas/química , Caveolina 1/metabolismo , Microdominios de Membrana/metabolismo , Proteínas de la Membrana/metabolismo , N-Acetilglucosaminiltransferasas/metabolismo , Proteoma/metabolismo , Proteínas de Unión al ARN/metabolismo , Animales , Caveolas/metabolismo , Caveolina 1/genética , Línea Celular Tumoral , Endocitosis , Aparato de Golgi , Marcaje Isotópico , Microdominios de Membrana/química , Proteínas de la Membrana/genética , Ratones , N-Acetilglucosaminiltransferasas/genética , Matriz Nuclear , Estructura Terciaria de Proteína , Proteínas de Unión al ARN/genética
11.
Adv Exp Med Biol ; 729: 29-50, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22411312

RESUMEN

Caveolins (Cavs) are integrated plasma membrane proteins that are complex signaling regulators with numerous partners and whose activity is highly dependent on cellular context. Cavs are both positive and negative regulators of cell signaling in and/or out of caveolae, invaginated lipid raft domains whose formation is caveolin expression dependent. Caveolins and rafts have been implicated in membrane compartmentalization; proteins and lipids accumulate in these membrane microdomains where they transmit fast, amplified and specific signaling cascades. The concept of plasma membrane organization within functional rafts is still in exploration and sometimes questioned. In this chapter, we discuss the opposing functions of caveolin in cell signaling regulation focusing on the role of caveolin both as a promoter and inhibitor of different signaling pathways and on the impact of membrane domain localization on caveolin functionality in cell proliferation, survival, apoptosis and migration.


Asunto(s)
Caveolina 1/metabolismo , Transducción de Señal , Animales , Caveolas/metabolismo , Caveolina 1/química , Línea Celular , Humanos , Estructura Terciaria de Proteína , Proteínas Tirosina Quinasas Receptoras/metabolismo
12.
Clin Nutr ; 41(9): 1896-1905, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35944296

RESUMEN

BACKGROUND & AIMS: The health benefit of human milk (HM) for preterm infant development is known but the role of human milk oligosaccharides (HMOs) contained in HM remains underexplored. We explored the relationship between exposure to HMOs contained in mother's milk and growth and neurodevelopment at 2-years corrected age in preterm infants. METHODS: Exclusively breastfed preterm infants born between 27 and 34 weeks of gestation were enrolled in a monocentric prospective observational study, LACTACOL. Samples of breast milk were collected once a week for 7 weeks after birth. HMOs and sialic acid were measured by liquid chromatography. Age and Stages questionnaire (ASQ) version 2 was used to assess 2-year neurodevelopmental outcome. We analyzed the relationship between HMO content and (i) infant neurodevelopment at 2-years, and (ii) growth outcome at discharge and at 2 years. A secondary analysis was performed among Secretor(+) Lewis(+) mothers. Only associations with a false discovery rate of 10% or less according to the Benjamini-Hochberg procedure were considered significant. RESULTS: 137 preterm infants (mean gestational age of 31.3 ± 1.7 weeks, mean birth weight of 1494 g ± 336 g) born to 117 mothers (mean age of 30.8 ± 5.0 years) were enrolled. Total HMOs and most individual HMOs and sialic acid concentrations decreased with advancing postnatal age, except for lacto-N-fucopentaose-III and 3-fucosyllactose, which increased. Total HMOs were positively correlated with neonatal length growth (adjusted p = 0.012). Neither total HMOs nor any individual HMO correlated with ASQ score in the overall cohort. However, lacto-N-fucopentaose-III (LNFP-III) was significantly associated with total ASQ score (adjusted p ≤ 0.015) among the 104 infants born to Secretor(+) Lewis(+) mothers. CONCLUSIONS: In this exploratory study in very preterm infants, total HMOs and most individual HMOs, except LNFP-III, decreased with advancing postnatal age. Neither the concentration of total HMOs nor that of any individual HMO were associated with ASQ score at 2 years, except for LNFP-III in Secretor(+) Lewis(+) mothers.


Asunto(s)
Recien Nacido Prematuro , Leche Humana , Adulto , Lactancia Materna , Niño , Femenino , Humanos , Lactante , Recién Nacido , Leche Humana/química , Ácido N-Acetilneuramínico/análisis , Oligosacáridos
13.
Arch Dis Child Fetal Neonatal Ed ; 106(6): 591-595, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33789971

RESUMEN

OBJECTIVE: Previous studies have assessed breastfeeding-support programmes. Among these, osteopathic manipulative treatment (OMT) is a frequently used approach, although without strong evidence of efficacy. METHODS: A double-blind randomised controlled trial was conducted between July 2013 and March 2016. Breastfed term infants were eligible if one of the following criteria was met: suboptimal breastfeeding behaviour, maternal cracked nipples or maternal pain. The infants were randomly assigned to the intervention or the control group. The intervention consisted of two sessions of early OMT, while in the control group, the manipulations were performed on a doll behind a screen. The primary outcome was the exclusive breastfeeding rate at 1 month, which was assessed in an intention-to-treat analysis. Randomisation was computer generated and only accessible to the osteopath practitioner. The parents, research assistants and paediatricians were masked to group assignment. RESULTS: One hundred twenty-eight mother-infant dyads were randomised, with 64 assigned to each group. In each group, five infants were lost to follow-up. In the intervention group, 31 of 59 (53%) of infants were still exclusively breast fed at 1 month vs 39 of 59 (66%) in the control group, (OR 0.55, 95% CI 0.26 to 1.17; p=0.12). After adjustment for suboptimal breastfeeding behaviour, caesarean section, use of supplements and breast shields, the adjusted OR was 0.44 (95% CI 0.17 to 1.11; p=0.08). No adverse effects were reported in either group. CONCLUSION: OMT did not improve exclusive breast feeding at 1 month. TRIAL REGISTRATION NUMBER: NCT01890668.


Asunto(s)
Lactancia Materna , Cuidado del Lactante , Osteopatía/métodos , Relaciones Madre-Hijo , Adulto , Lactancia Materna/métodos , Lactancia Materna/psicología , Método Doble Ciego , Femenino , Humanos , Cuidado del Lactante/métodos , Cuidado del Lactante/psicología , Recién Nacido , Análisis de Intención de Tratar , Masculino , Conducta Materna , Evaluación de Procesos y Resultados en Atención de Salud , Resultado del Tratamiento
14.
Cells ; 9(1)2020 01 08.
Artículo en Inglés | MEDLINE | ID: mdl-31936361

RESUMEN

Angiopoietin-1 (Ang-1) is an important proangiogenic factor also involved in the maintenance of endothelial-barrier integrity. The small GTPase Rap1 is involved in the regulation of adherens junctions through VE-cadherin-mediated adhesion, and in endothelial permeability. While many studies established that Rap1 activation is critical for endothelial cell-cell adhesions, its roles in the antipermeability effects of Ang-1 are ill-defined. Thus, we determined the contribution of Rap1 to Ang-1-stimulated angiogenic effects on endothelial cells (ECs). We found that Rap1 is activated following Ang-1 stimulation and is required for the antipermeability effects of Ang-1 on EC monolayers. Our results also revealed that Rap1 is necessary for EC sprouting stimulated by Ang-1 but had no significant effect on Ang-1-induced EC migration and adhesion. In contrast, downregulation of VE-cadherin markedly increased the adhesiveness of ECs to the substratum, which resulted in inhibition of Ang-1-stimulated migration. These results revealed that Rap1 is central to the effects of Ang-1 at intercellular junctions of ECs, whereas VE-cadherin is also involved in the adhesion of ECs to the extracellular matrix.


Asunto(s)
Angiopoyetina 1/farmacología , Aorta/fisiología , Adhesión Celular , Comunicación Celular , Endotelio Vascular/fisiología , Proteínas de Unión al GTP rap1/metabolismo , Animales , Aorta/citología , Aorta/efectos de los fármacos , Bovinos , Células Cultivadas , Endotelio Vascular/citología , Endotelio Vascular/efectos de los fármacos , Transducción de Señal , Proteínas de Unión al GTP rap1/genética
15.
Front Pediatr ; 8: 127, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32363168

RESUMEN

Context: The incidence of early-onset neonatal infection has greatly decreased, but a new diagnostic approach is needed to avoid overdiagnosis and overtreatment. The aim of this study was to assess the potential impact of an algorithm incorporating umbilical-cord-blood procalcitonin (PCT) level on neonatal antibiotics prescription rate as compared with current practice. Material and methods: We conducted a prospective study in three maternity wards in France. All term and preterm neonates with the usual risk factors for neonatal group B Streptococcus infection were eligible for umbilical-cord-blood PCT testing. We compared the proportion of neonates who were exposed early to antibiotics (before 6 days of life) to that of neonates for whom antibiotics prescription would be indicated according to the PCT-based algorithm. Results: Among the 3,080 neonates included, 1 neonate presented with certain infection and 38 neonates with probable infection. The global antibiotics prescription rate was 4.6% [95% confidence interval (CI), 4.1-5]. With the PCT-based algorithm, the potential decrease in prescription rate would be 1.8% (95% CI, 1.3-2.3), corresponding to a 39% (95% CI, 37.3-40.7) relative reduction in antibiotics exposure (p < 0.05). Conclusion: These results suggest that the umbilical-cord-blood PCT-based algorithm could significantly help the clinicians in their antibiotic prescription decision to decrease neonatal antibiotics exposure as compared with current practice. If validated in a larger interventional randomized study, this approach could help clinicians stratify the risk of early-onset neonatal infection and initiate early antibiotics treatment in newborns at high risk of infection while limiting the deleterious effects of useless prescriptions in non-infected newborns.

16.
J Neurosci ; 28(23): 5879-90, 2008 Jun 04.
Artículo en Inglés | MEDLINE | ID: mdl-18524892

RESUMEN

The adhesion molecule N-cadherin plays important roles in the development of the nervous system, in particular by stimulating axon outgrowth, but the molecular mechanisms underlying this effect are mostly unknown. One possibility, the so-called "molecular clutch" model, could involve a direct mechanical linkage between N-cadherin adhesion at the membrane and intracellular actin-based motility within neuronal growth cones. Using live imaging of primary rat hippocampal neurons plated on N-cadherin-coated substrates and optical trapping of N-cadherin-coated microspheres, we demonstrate here a strong correlation between growth cone velocity and the mechanical coupling between ligand-bound N-cadherin receptors and the retrograde actin flow. This relationship holds by varying ligand density and expressing mutated N-cadherin receptors or small interfering RNAs to perturb binding to catenins. By restraining microsphere motion using optical tweezers or a microneedle, we further show slippage of cadherin-cytoskeleton bonds at low forces, and, at higher forces, local actin accumulation, which strengthens nascent N-cadherin contacts. Together, these data support a direct transmission of actin-based traction forces to N-cadherin adhesions, through catenin partners, driving growth cone advance and neurite extension.


Asunto(s)
Actinas/fisiología , Cadherinas/fisiología , Movimiento Celular/fisiología , Conos de Crecimiento/fisiología , Animales , Adhesión Celular/fisiología , Células Cultivadas , Pollos , Conos de Crecimiento/ultraestructura , Neuritas/fisiología , Neuronas/citología , Neuronas/diagnóstico por imagen , Neuronas/fisiología , Radiografía , Ratas , Xenopus
17.
Cell Signal ; 20(6): 1061-72, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18302981

RESUMEN

Cadherin-11 is a cell-cell adhesion molecule whose expression is often correlated with cellular migratory phenomena. We recently demonstrated that cadherin-11 activation by immobilized cad11-Fc (cadherin-11 ectodomain fused to Fc fragment) promotes axonal extension of spinal cord explants. Here, we show that this induced neurite outgrowth is dependent on the FGF receptor (FGFR) activity. Downstream, DAG lipase/CAM kinase and PI3 kinase pathways are required, but not the MAP kinase signalling. We also demonstrate that a tagged form of FGFR1 co-immunoprecipitates with beta-catenin containing cadherin-11 immunocomplexes. FGFR1 and beta-catenin show colocalization and enhanced association during cadherin-11 engagement, suggesting that FGFR1 interaction with cadherin-11 adhesion complexes is reinforced during cell contact formation. In vitro pull-down experiments using recombinant ectodomains suggest that cadherin-11/FGFR interact directly through their extracellular domains. Altogether, we propose that cadherin-11 recruits the FGFR upon adhesive engagement at nascent contacts, triggering the activation of downstream pathways involved in growth cone progression.


Asunto(s)
Cadherinas/metabolismo , Neuritas/enzimología , Receptores de Factores de Crecimiento de Fibroblastos/metabolismo , Transducción de Señal , Animales , Cadherinas/genética , Cadherinas/farmacología , Proteínas Quinasas Dependientes de Calcio-Calmodulina/metabolismo , Línea Celular , Membrana Celular/metabolismo , Células Cultivadas , Humanos , Lipoproteína Lipasa/metabolismo , Ratones , Neuritas/ultraestructura , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Recombinantes de Fusión/farmacología
18.
Mol Biol Cell ; 30(17): 2227-2239, 2019 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-31141452

RESUMEN

Binding of angiopoietin-1 (Ang-1) to its receptor Tie2 on endothelial cells (ECs) promotes vessel barrier integrity and angiogenesis. Here, we identify PAK2 and paxillin as critical targets of Ang-1 responsible for EC migration, polarization, and sprouting. We found that Ang-1 increases PAK2-dependent paxillin phosphorylation and remodeling of focal adhesions and that PAK2 and paxillin are required for EC polarization, migration, and angiogenic sprouting in response to Ang-1. Our findings show that Ang-1 triggers Cdc42 activation at the leading edges of migrating ECs, which is dependent on PAK2 and paxillin expression. We also established that the polarity protein Par3 interacts with Cdc42 in response to Ang-1 in a PAK2- and paxillin-dependent manner. Par3 is recruited at the leading edges of migrating cells and in focal adhesion, where it forms a signaling complex with PAK2 and paxillin in response to Ang-1. These results show that Ang-1 triggers EC polarization and angiogenic sprouting through PAK2-dependent paxillin activation and remodeling of focal adhesions, which are necessary for local activation of Cdc42 and the associated polarity complex. We have shown that PAK2 controls a signaling pathway important for angiogenic sprouting that links focal adhesions to polarity signaling in ECs.


Asunto(s)
Angiopoyetina 1/metabolismo , Paxillin/metabolismo , Proteína de Unión al GTP cdc42/metabolismo , Quinasas p21 Activadas/metabolismo , Animales , Aorta/metabolismo , Bovinos , Adhesión Celular/fisiología , Movimiento Celular/fisiología , Polaridad Celular/fisiología , Células Endoteliales/citología , Células Endoteliales/metabolismo , Adhesiones Focales/metabolismo , Neovascularización Fisiológica , Fosforilación , Receptor TIE-2 , Transducción de Señal , Quinasas p21 Activadas/fisiología
19.
Stem Cell Res Ther ; 10(1): 166, 2019 06 13.
Artículo en Inglés | MEDLINE | ID: mdl-31196173

RESUMEN

BACKGROUND: Cell reprogramming is a promising avenue for cell-based therapies as it allows for the generation of multipotent, unipotent, or mature somatic cells without going through a pluripotent state. While the use of autologous cells is considered ideal, key challenges for their clinical translation include the ability to reproducibly generate sufficient quantities of cells within a therapeutically relevant time window. METHODS: We performed transfection of three distinct human somatic starting populations of cells with a non-integrating synthetic plasmid expressing Musashi 1 (MSI1), Neurogenin 2 (NGN2), and Methyl-CpG-Binding Domain 2 (MBD2). The resulting directly reprogrammed neural precursor cells (drNPCs) were examined in vitro using RT-qPCR, karyotype analysis, immunohistochemistry, and FACS at early and late time post-transfection. Electrophysiology (patch clamp) was performed on drNPC-derived neurons to determine their capacity to generate action potentials. In vivo characterization was performed following transplantation of drNPCs into two animal models (Shiverer and SCID/Beige mice), and the numbers, location, and differentiation profile of the transplanted cells were examined using immunohistochemistry. RESULTS: Human somatic cells can be directly reprogrammed within two weeks to neural precursor cells (drNPCs) by transient exposure to Msi1, Ngn2, and MBD2 using non-viral constructs. The drNPCs generate all three neural cell types (astrocytes, oligodendrocytes, and neurons) and can be passaged in vitro to generate large numbers of cells within four weeks. drNPCs can respond to in vivo differentiation and migration cues as demonstrated by their migration to the olfactory bulb and contribution to neurogenesis in vivo. Differentiation profiles of transplanted cells onto the corpus callosum of myelin-deficient mice reveal the production of oligodendrocytes and astrocytes. CONCLUSIONS: Human drNPCs can be efficiently and rapidly produced from donor somatic cells and possess all the important characteristics of native neural multipotent cells including differentiation into neurons, astrocytes, and oligodendrocytes, and in vivo neurogenesis and myelination.


Asunto(s)
Células-Madre Neurales/metabolismo , Neuronas/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Diferenciación Celular/genética , Diferenciación Celular/fisiología , Células Cultivadas , Reprogramación Celular/genética , Reprogramación Celular/fisiología , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Electrofisiología , Citometría de Flujo , Humanos , Cariotipo , Masculino , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Células-Madre Neurales/citología , Neurogénesis/genética , Neurogénesis/fisiología , Neuronas/citología , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Remielinización/genética , Remielinización/fisiología
20.
Nutrients ; 10(2)2018 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-29385065

RESUMEN

Human milk is recommended for feeding preterm infants. The current pilot study aims to determine whether breast-milk lipidome had any impact on the early growth-pattern of preterm infants fed their own mother's milk. A prospective-monocentric-observational birth-cohort was established, enrolling 138 preterm infants, who received their own mother's breast-milk throughout hospital stay. All infants were ranked according to the change in weight Z-score between birth and hospital discharge. Then, we selected infants who experienced "slower" (n = 15, -1.54 ± 0.42 Z-score) or "faster" (n = 11, -0.48 ± 0.19 Z-score) growth; as expected, although groups did not differ regarding gestational age, birth weight Z-score was lower in the "faster-growth" group (0.56 ± 0.72 vs. -1.59 ± 0.96). Liquid chromatography-mass spectrometry lipidomic signatures combined with multivariate analyses made it possible to identify breast-milk lipid species that allowed clear-cut discrimination between groups. Validation of the selected biomarkers was performed using multidimensional statistical, false-discovery-rate and ROC (Receiver Operating Characteristic) tools. Breast-milk associated with faster growth contained more medium-chain saturated fatty acid and sphingomyelin, dihomo-γ-linolenic acid (DGLA)-containing phosphethanolamine, and less oleic acid-containing triglyceride and DGLA-oxylipin. The ability of such biomarkers to predict early-growth was validated in presence of confounding clinical factors but remains to be ascertained in larger cohort studies.


Asunto(s)
Desarrollo Infantil , Cabeza/crecimiento & desarrollo , Recien Nacido Prematuro/crecimiento & desarrollo , Lípidos/análisis , Leche Humana/química , Aumento de Peso , Factores de Edad , Peso al Nacer , Estatura , Índice de Masa Corporal , Cefalometría , Cromatografía Líquida de Alta Presión , Cromatografía de Fase Inversa , Francia , Edad Gestacional , Humanos , Recién Nacido , Proyectos Piloto , Estudios Prospectivos , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masas en Tándem , Factores de Tiempo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA