151 research outputs found
Heparan Sulfate Proteoglycans Mediate the Angiogenic Activity of the Vascular Endothelial Growth Factor Receptor-2 Agonist Gremlin.
OBJECTIVE: Heparan sulfate proteoglycans (HSPGs) modulate the interaction of proangiogenic heparin-binding vascular endothelial growth factors (VEGFs) with signaling VEGF receptor-2 (VEGFR2) and neuropilin coreceptors in endothelial cells (ECs). The bone morphogenic protein antagonist gremlin is a proangiogenic ligand of VEGFR2, distinct from canonical VEGFs. Here we investigated the role of HSPGs in VEGFR2 interaction, signaling, and proangiogenic capacity of gremlin in ECs.
METHODS AND RESULTS: Surface plasmon resonance demonstrated that gremlin binds heparin and heparan sulfate, but not other glycosaminoglycans, via N-, 2-O, and 6-O-sulfated groups of the polysaccharide. Accordingly, gremlin binds HSPGs of the EC surface and extracellular matrix. Gremlin/HSPG interaction is prevented by free heparin and heparan sulfate digestion or undersulfation following EC treatment with heparinase II or sodium chlorate. However, at variance with canonical heparin-binding VEGFs, gremlin does not interact with neuropilin-1 coreceptor. On the other hand, HSPGs mediate VEGFR2 engagement and autophosphorylation, extracellular signaling-regulated kinase(1/2) and p38 mitogen-activated protein kinase activation, and consequent proangiogenic responses of ECs to gremlin. On this basis, we evaluated the gremlin-antagonist activity of a panel of chemically sulfated derivatives of the Escherichia coli K5 polysaccharide. The results demonstrate that the highly N,O-sulfated derivative K5-N,OS(H) binds gremlin with high potency, thus inhibiting VEGFR2 interaction and angiogenic activity in vitro and in vivo.
CONCLUSIONS: HSPGs act as functional gremlin coreceptors in ECs, affecting its productive interaction with VEGFR2 and angiogenic activity. This has allowed the identification of the biotechnological K5-N,OS(H) as a novel angiostatic gremlin antagonist
Nanoscale effects on the ionic conductivity of highly doped bulk nanometric cerium oxide
Nanometric ceria powders doped with 30 mol % samaria are consolidated by a high-pressure spark plasma sintering (HP-SPS) method to form > 99 % dense samples with a crystallite size as small as 16.5 nm. A conductivity dependence on grain size was noted: when the grain size was less than 20 nm, only one semicircle in the AC impedance spectra was observed and was attributed to bulk conductivity. In contrast to previous observations on pure ceria, the disappearance of the grain-boundary blocking effect is not associated with mixed conductivity. With annealing and concomitant grain growth, the samples show the presence of a grain-boundary effect
Molecular Interaction Studies of HIV-1 Matrix Protein p17 and Heparin: IDENTIFICATION OF THE HEPARIN-BINDING MOTIF OF p17 AS A TARGET FOR THE DEVELOPMENT OF MULTITARGET ANTAGONISTS
Once released by HIV cells, p17 binds heparan sulfate proteoglycans
(HSPGs) and CXCR1 on leukocytes causing their
dysfunction. By exploiting an approach integrating computational
modeling, site-directed mutagenesis of p17, chemical
desulfation of heparin, and surface plasmon resonance, we characterized
the interaction of p17 with heparin, a HSPG structural
analog, and CXCR1. p17 binds to heparin with an affinity (Kd
190 nM) that is similar to those of other heparin-binding viral
proteins. Two stretches of basic amino acids (basic motifs) are
present in p17 N and C termini. Neutralization (Arg3Ala substitution)
of the N-terminal, but not of the C-terminal basic
motif, causes the loss of p17 heparin-binding capacity. The
N-terminal heparin-binding motif of p17 partially overlaps the
CXCR1-binding domain. Accordingly, its neutralization prevents
also p17 binding to the chemochine receptor. Competition
experiments demonstrated that free heparin and heparan
sulfate (HS), but not selectively 2-O-, 6-O-, and N-O desulfated
heparins, prevent p17 binding to substrate-immobilized heparin,
indicating that the sulfate groups of the glycosaminoglycan
mediate p17 interaction. Evaluation of the p17 antagonist activity
of a panel of biotechnological heparins derived by chemical
sulfation of the Escherichia coli K5 polysaccharide revealed that
the highlyN,O-sulfated derivative prevents the binding of p17 to
both heparin and CXCR1, thus inhibiting p17-driven chemotactic
migration of human monocytes with an efficiency that is
higher than those of heparin and HS. Here, we characterized at a
molecular level the interaction of p17 with its cellular receptors,
laying the basis for the development of heparin-mimicking p17
antagonists
N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (BOC2) inhibits the angiogenic activity of heparin-binding growth factors.
The peptides N-tert-butyloxycarbonyl-Phe-Leu-Phe-Leu-Phe (BOC2) and BOC-Met-Leu-Phe (BOC1) are widely used antagonists of formyl peptide receptors (FPRs), BOC2 acting as an FPR1/FPR2 antagonist whereas BOC1 inhibits FPR1 only. Extensive investigations have been performed by using these FPR antagonists as a tool to assess the role of FPRs in physiological and pathological conditions. Based on previous observations from our laboratory, we assessed the possibility that BOC2 may exert also a direct inhibitory effect on the angiogenic activity of vascular endothelial growth factor-A (VEGF-A). Our data demonstrate that BOC2, but not BOC1, inhibits the angiogenic activity of heparin-binding VEGF-A165 with no effect on the activity of the non-heparin-binding VEGF-A121 isoform. Endothelial cell-based bioassays, surface plasmon resonance analysis, and computer modeling indicate that BOC2 may interact with the heparin-binding domain of VEGF-A165, thus competing for heparin interaction and preventing the binding of VEGF-A165 to tyrosine kinase receptor VEGFR2, its phosphorylation and downstream signaling. In addition, BOC2 inhibits the interaction of a variety of heparin-binding angiogenic growth factors with heparin, including fibroblast growth factor 2 (FGF2) whose angiogenic activity is blocked by the compound. Accordingly, BOC2 suppresses the angiogenic potential of human tumor cell lines that co-express VEGF-A and FGF2. Thus, BOC2 appears to act as a novel multi-heparin-binding growth factor antagonist. These findings caution about the interpretation of FPR-focusing experimental data obtained with this compound and set the basis for the design of novel BOC2-derived, FPR independent multi-target angiogenesis inhibitors
The Pro-Oncogenic Sphingolipid-Metabolizing Enzyme β-Galactosylceramidase Modulates the Proteomic Landscape in BRAF(V600E)-Mutated Human Melanoma Cells
beta-Galactosylceramidase (GALC) is a lysosomal enzyme involved in sphingolipidmetabolismby removing beta-galactosyl moieties from fi-galactosylceramide and beta-galactosylsphingosine. Previous observations have shown that GALC may exert pro-oncogenic functions in melanoma and Galc silencing, leading to decreased oncogenic activity in murine B16 melanoma cells. The tumor-driving BRAF(V600E) mutation is present in approximately 50% of human melanomas and represents a major therapeutic target. However, such mutation is missing in melanoma B16 cells. Thus, to assess the impact of GALC in human melanoma in a more relevant BRAF-mutated background, we investigated the effect of GALC overexpression on the proteomic landscape of A2058 and A375 human melanoma cells harboring the BRAF(V600E) mutation. The results obtained by liquid chromatography-tandem mass spectrometry (LC-MS/MS) demonstrate that significant differences exist in the protein landscape expressed under identical cell culture conditions by A2058 and A375 human melanoma cells, both harboring the same BRAF(V600E)-activating mutation. GALC overexpression resulted in a stronger impact on the proteomic profile of A375 cells when compared to A2058 cells (261 upregulated and 184 downregulated proteins versus 36 and 14 proteins for the two cell types, respectively). Among them, 25 proteins appeared to be upregulated in both A2058-upGALC and A375-upGALC cells, whereas two proteins were significantly downregulated in both GALC-overexpressing cell types. These proteins appear to be involved in melanoma biology, tumor invasion and metastatic dissemination, tumor immune escape, mitochondrial antioxidant activity, endoplasmic reticulum stress responses, autophagy, and/or apoptosis. Notably, analysis of the expression of the corresponding genes in human skin cutaneous melanoma samples (TCGA, Firehose Legacy) using the cBioPortal for Cancer Genomics platform demonstrated a positive correlation between GALC expression and the expression levels of 14 out of the 27 genes investigated, thus supporting the proteomic findings. Overall, these data indicate for the first time that the expression of the lysosomal sphingolipid-metabolizing enzyme GALC may exert a pro-oncogenic impact on the proteomic landscape in BRAF-mutated human melanoma
Marteletes desgastados afetam negativamente as características operacionais da moagem e físicas do milho processado em moinho do tipo martelo
Foi conduzido um trabalho para avaliar os efeitos dos níveis de desgaste de marteletes de moinho tipo martelo, sobre características físicas do milho e operacionais de moagem. Foram utilizados quatro diferentes lotes de milho, um moinho martelo com motor de 3.500 RPM, cinco conjuntos de marteletes com diferentes níveis de desgaste do vértice (0, 20, 43, 57 e 63%) e quatro diferentes peneiras com diâmetros de furos de 1, 3, 5 e 12 mm sob um esquema fatorial 5x4, com quatro repetições em um total de 80 unidades experimentais. O aumento no diâmetro dos furos das peneiras influenciou (P<0,05) com aumento na produção, nos decibéis, no diâmetro geométrico médio (DGM), no desvio padrão geométrico (DPG), na densidade e com redução no consumo de energia elétrica e no ângulo de repouso (AR). O maior desgaste do martelo aumentou (P<0,05) o consumo de energia elétrica, DGM, DPG, AR e com redução (P<0,05) na produtividade e densidade. A análise de Linear response plateau (LRP) indicou piora na produtividade do equipamento a partir dos 55,1% de desgaste. Neste contexto, o desgaste dos marteletes influenciou negativamente as características operacionais do equipamento e físicas do milho. Para favorecer as características físicas do milho moído e evitar perdas na produtividade do equipamento recomenda-se a moagem com martelos isentos de desgaste
Iron supplementation enhances RSL3-induced ferroptosis to treat naïve and prevent castration-resistant prostate cancer
Prostate cancer (PCa) is a leading cause of death in the male population commonly treated with androgen deprivation therapy that often relapses as androgen-independent and aggressive castration-resistant prostate cancer (CRPC). Ferroptosis is a recently described form of cell death that requires abundant cytosolic labile iron to promote membrane lipid peroxidation and which can be induced by agents that inhibit the glutathione peroxidase-4 activity such as RSL3. Exploiting in vitro and in vivo human and murine PCa models and the multistage transgenic TRAMP model of PCa we show that RSL3 induces ferroptosis in PCa cells and demonstrate for the first time that iron supplementation significantly increases the effect of RSL3 triggering lipid peroxidation, enhanced intracellular stress and leading to cancer cell death. Moreover, the combination with the second generation anti-androgen drug enzalutamide potentiates the effect of the RSL3 + iron combination leading to superior inhibition of PCa and preventing the onset of CRPC in the TRAMP mouse model. These data open new perspectives in the use of pro-ferroptotic approaches alone or in combination with enzalutamide for the treatment of PCa
Effects of a brief mindfulness-based intervention on emotional regulation and levels of mindfulness in senior students
Mindfulness-based interventions have been applied in diverse populations and achieved mental health benefits. This study examined the effects of a brief mindfulness program for emotional regulation and levels of mindfulness on senior students in Brazil. The intervention consisted of six weekly meetings attended by 30 participants. It is a pre-experimental research, with pre- and post-test comparative and correlation measurements. The preliminary results, which relied on parametrical and non-parametrical tests, revealed a reduction in total emotional regulation difficulties (p = 0.0001; r = − 0.55). Also, there was an increase in the levels of mindfulness in the subtests for both dimensions under evaluation: “Awareness” (p = 0.0001; d = 0.77) and “Acceptance” (p = 0.048; d = 0.37). By associating the amount of meditative practices performed by students with the variables, a significant positive correlation was found with the mindfulness dimension “Awareness” (rP = 0.422; p = 0.020), and there was a significant negative correlation with Difficulties in emotion regulation (rS = − 0.478; p = 0.008) and with its respective subscales “Non-acceptance” (rS = − 0.654; p = 0.0001) and “Clarity” (rS = − 0.463; p = 0.010). In conclusion, the application of a brief mindfulness-based intervention is promising in Brazilian university contexts; moreover, it can bring benefits to students, e.g., an increase in emotion regulation as well as in levels of mindfulness. We suggest that further research should use an experimental design and follow-up.info:eu-repo/semantics/publishedVersio
Associação entre funções estomatognáticas, oclusão dentária e sinais de disfunção temporomandibular em mulheres assintomáticas
OBJETIVO: verificar a associação entre funções estomatognáticas de mastigação e deglutição, oclusão dentária e sinais de disfunção temporomandibular em mulheres assintomáticas. MÉTODOS: as funções estomatognáticas foram avaliadas pelo exame miofuncional orofacial; o exame da oclusão dentária compreendeu: classificação de Angle; medidas de sobrepasse horizontal e vertical; presença de mordida aberta e cruzada; e a avaliação da articulação temporomandibular foi realizada pelo instrumento Critérios de Diagnóstico para Pesquisa de Desordens Temporomandibulares. RESULTADOS: foram avaliadas 43 mulheres com idade média de 23,7 anos. O exame miofuncional orofacial demonstrou alterações no padrão de mastigação (30,2%) e contrações atípicas na mastigação (18,6%) e deglutição (58,1%). Quanto à oclusão dentária, houve predomínio de classe I de Angle (74,4%), porém nenhuma voluntária apresentou uma oclusão ideal. A avaliação da articulação temporomandibular apresentou amplitude de movimento dentro da normalidade, presença de desvio na abertura da boca (60,5%) e diagnóstico de disfunção temporomandibular (16,3%). Houve associação significante entre presença de ruídos articulares e diagnóstico de disfunção temporomandibular e contrações atípicas na deglutição; padrão de abertura e contrações atípicas na mastigação; e não houve associação entre a Classe Oclusal de Angle, padrão de mastigação e disfunção temporomandibular. CONCLUSÃO: voluntárias assintomáticas apresentaram alterações das funções estomatognáticas, como contrações atípicas durante a deglutição e mastigação, as quais foram associadas com a presença de ruídos articulares e padrão de abertura da boca. Tais achados podem ser atribuídos a desequilíbrios e incoordenação dos músculos envolvidos nessas funções. Nenhuma voluntária apresentou oclusão ideal e não foram encontradas associações com esta condição
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