Browsing by Author "Lopes, MC"
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- Amplified and Homozygously Deleted Genes in Glioblastoma: Impact on Gene Expression LevelsPublication . Crespo, I; Tão, H; Nieto, AB; Rebelo, O; Domingos, P; Vital, AL; Patino, MC; Barbosa, MD; Lopes, MC; Resende de Oliveira, C; Orfão, A; Tabernero, MDBACKGROUND: Glioblastoma multiforme (GBM) displays multiple amplicons and homozygous deletions that involve relevant pathogenic genes and other genes whose role remains unknown. METHODOLOGY: Single-nucleotide polymorphism (SNP)-arrays were used to determine the frequency of recurrent amplicons and homozygous deletions in GBM (n = 46), and to evaluate the impact of copy number alterations (CNA) on mRNA levels of the genes involved. PRINCIPAL FINDINGS: Recurrent amplicons were detected for chromosomes 7 (50%), 12 (22%), 1 (11%), 4 (9%), 11 (4%), and 17 (4%), whereas homozygous deletions involved chromosomes 9p21 (52%) and 10q (22%). Most genes that displayed a high correlation between DNA CNA and mRNA levels were coded in the amplified chromosomes. For some amplicons the impact of DNA CNA on mRNA expression was restricted to a single gene (e.g., EGFR at 7p11.2), while for others it involved multiple genes (e.g., 11 and 5 genes at 12q14.1-q15 and 4q12, respectively). Despite homozygous del(9p21) and del(10q23.31) included multiple genes, association between these DNA CNA and RNA expression was restricted to the MTAP gene. CONCLUSIONS: Overall, our results showed a high frequency of amplicons and homozygous deletions in GBM with variable impact on the expression of the genes involved, and they contributed to the identification of other potentially relevant genes.
- Contact sensitizers downregulate the expression of the chemokine receptors CCR6 and CXCR4 in a skin dendritic cell linePublication . Cruz, MT; Gonçalo, Margarida; Paiva, A; Morgado, JM; Figueiredo, A; Duarte, CB; Lopes, MCChemokines are involved in the control of dendritic cell (DC) trafficking, which is critical for the immune response, namely in allergic contact dermatitis (ACD). In this work, we investigated by flow cytometry the effect of the contact sensitizers 2,4-dinitrofluorobenzene (DNFB), 1,4-phenylenediamine (PPD) and nickel sulfate (NiSO(4)), on the surface expression of the chemokine receptors CCR6 and CXCR4 in DC. As an experimental model of a DC we used a fetal skin-derived dendritic cell line (FSDC), which has morphological, phenotypical and functional characteristics of skin DC. Our results show that all the skin sensitizers studied decreased the membrane expression of the chemokine receptors CCR6 and CXCR4. In contrast, 2,4-dichloronitrobenzene (DCNB), the inactive analogue of DNFB without contact sensitizing properties, was without effect on the surface expression of these receptors. Lipopolysaccharide (LPS), which induces the maturation of DC, also reduced surface CCR6 and CXCR4 expression.
- Dexamethasone prevents granulocyte-macrophage colony-stimulating factor-induced nuclear factor-kappaB activation, inducible nitric oxide synthase expression and nitric oxide production in a skin dendritic cell line.Publication . Vital, AL; Gonçalo, Margarida; Cruz, MT; Figueiredo, A; Duarte, CB; Lopes, MCAIMS: Nitric oxide (NO) has been increasingly implicated in inflammatory skin diseases, namely in allergic contact dermatitis. In this work, we investigated the effect of dexamethasone on NO production induced by the epidermal cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) in a mouse fetal skin dendritic cell line. METHODS: NO production was assessed by the method of Griess. Expression of the inducible isoform of nitric oxide synthase (iNOS) protein was evaluated by western blot analysis and immunofluorescence microscopy. Western blot analysis was also performed to evaluate cytosolic IkappaB-alpha (IkappaB-alpha) protein levels. The electrophoretic mobility shift assay was used to evaluate the activation or inhibition of nuclear factor kappa B (NF-kappaB). RESULTS: GM-CSF induced iNOS expression and NO production, and activated the transcription factor NF-kappaB. Dexamethasone inhibited, in a dose-dependent manner, NO production induced by GM-CSF. Addition of dexamethasone to the culture, 30 min before GM-CSF stimulation, significantly inhibited the cellular expression of iNOS. Dexamethasone also inhibited GM-CSF-induced NF-kappaB activation by preventing a significant decrease on the IkappaB-alpha protein levels, thus blocking NF-kappaB migration to the nucleus. CONCLUSIONS: The corticosteroid dexamethasone inhibits GM-CSF-induced NF-kappaB activation, iNOS protein expression and NO production. These results suggest that dexamethasone is a potent inhibitor of intracellular events that are involved on NO synthesis, in skin dendritic cells.
- Differential activation of nuclear factor kappa B subunits in a skin dendritic cell line in response to the strong sensitizer 2,4-dinitrofluorobenzenePublication . Cruz, MT; Duarte, CB; Gonçalo, Margarida; Figueiredo, A; Carvalho, AP; Lopes, MCDendritic cell (DC) maturation is essential for the initiation of T-dependent immune responses. Nuclear factor kappa B (NF-kappaB) transcription factors are ubiquitously expressed signalling molecules, known to regulate the transcription of a large number of genes involved in immune responses, including cytokines and cell surface molecules. In this work, we studied the time-dependent activation of five members of the NF-kappaB family, p50, p52, p65, RelB and cRel, in a mouse skin DC line in response to stimulation with the strong sensitizer, 2,4-dinitrofluorobenzene (DNFB). Western blot assay revealed that exposure of fetal skin DC (FSDC) to DNFB induced the degradation of the inhibitor of NF-kappaB (IkappaB). Three out of its five members, i.e. p50, p52, and RelB, were similarly activated upon DNFB stimulation, with subsequent translocation of these subunits from the cytosol to the nucleus, but with different kinetics. In contrast, p65 expression was diminished in both the nucleus and the cytosol. The electrophoretic mobility shift assay (EMSA) showed that exposure of FSDC to DNFB induced DNA binding to NF-kappaB. Together, these results show that DNFB differentially activates the various members of the NF-kappaB family in skin DC.
- Differential effects of the essential oils of Lavandula luisieri and Eryngium duriaei subsp. juresianum in cell models of two chronic inflammatory diseasesPublication . Rufino, AT; Ferreira, I; Judas, F; Salgueiro, L; Lopes, MC; Cavaleiro, C; Mendes, AFCONTEXT: Effective drugs to treat osteoarthritis (OA) and inflammatory bowel disease (IBD) are needed. OBJECTIVE: To identify essential oils (EOs) with anti-inflammatory activity in cell models of OA and IBD. MATERIALS AND METHODS: EOs from Eryngium duriaei subsp. juresianum (M. Laínz) M. Laínz (Apiaceae), Laserpitium eliasii subsp. thalictrifolium Sennen & Pau (Apiaceae), Lavandula luisieri (Rozeira) Rivas-Martínez (Lamiaceae), Othantus maritimus (L.) Hoff. & Link (Asteraceae), and Thapsia villosa L. (Apiaceae) were analyzed by GC and GC/MS. The anti-inflammatory activity of EOs (5-200 μg/mL) was evaluated by measuring inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB) activation (total and phosphorylated IκB-α), in primary human chondrocytes and the intestinal cell line, C2BBe1, stimulated with interleukin-1β (IL-1β) or interferon-γ (IFN-γ), IL-1β and tumor necrosis factor-α (TNF-α), respectively. RESULTS: The EO of L. luisieri significantly reduced iNOS (by 54.9 and 81.0%, respectively) and phosphorylated IκB-α (by 87.4% and 62.3%, respectively) in both cell models. The EO of E. duriaei subsp. juresianum caused similar effects in human chondrocytes, but was inactive in intestinal cells, even at higher concentrations. The EOs of L. eliasii subsp. thalictrifolium and O. maritimus decreased iNOS expression by 45.2 ± 8.7% and 45.2 ± 6.2%, respectively, in C2BBe1 cells and were inactive in chondrocytes. The EO of T. villosa was inactive in both cell types. DISCUSSION AND CONCLUSION: This is the first study showing anti-inflammatory effects of the EOs of L. luisieri and E. duriaei subsp. juresianum. These effects are specific of the cell type and may be valuable to develop new therapies or as sources of active compounds with improved efficacy and selectivity towards OA and IBD.
- Differential modulation of CXCR4 and CD40 protein levels by skin sensitizers and irritants in the FSDC cell linePublication . Neves, BM; Cruz, MT; Francisco, V; Gonçalo, Margarida; Figueiredo, A; Duarte, CB; Lopes, MCThe development of non-animal methods for skin sensitization testing is an urgent challenge. Some of the most promising in vitro approaches are based on the analysis of phenotypical and functional modifications induced by sensitizers in dendritic cell models. In this work, we evaluated, for the first time, a fetal skin-derived dendritic cell line (FSDC) as a model to discriminate between sensitizers and irritants, through analysis of their effects on CD40 and CXCR4 protein expression. The chemicals concentrations were chosen based on a slight cytotoxicity effect (up to 15%). Protein levels were evaluated by Western blot and immunocytochemistry, after stimulation with the skin sensitizers 2,4-dinitrofluorobenzene (DNFB), 1,4-phenylenediamine (PPD) and nickel sulphate (NiSO(4)), the non-sensitizer 2,4-dichloronitrobenzene (DCNB), and the irritants sodium dodecyl sulphate (SDS) and benzalkonium chloride (BC). All sensitizers tested increased CD40 and CXCR4 levels. In contrast, irritants decreased both proteins levels, with a more pronounced effect on CXCR4. In agreement with these results, dendritic cells derived from human peripheral blood monocytes-derived dendritic cells (MoDC) showed a similar response pattern to the skin sensitizer and irritant tested, PPD and SDS, respectively. In conclusion, evaluation of CD40 and CXCR4 proteins in chemical-treated FSDC may represent a useful tool in a future in vitro test for sensitizing assessment
- DNFB activates MAPKs and upregulates CD40 in skin-derived dendritic cellsPublication . Matos, TJ; Duarte, CB; Gonçalo, Margarida; Lopes, MCBACKGROUND: The intracellular mechanisms involved in the activation of DCs during sensitization in allergic contact dermatitis (ACD) are not known. OBJECTIVE: Here, we investigated the effect of a strong sensitizer, 2,4-dinitrofluorobenzene (DNFB) on the activity of MAPKs in a dendritic cell (DC) line generated from fetal mouse skin (FSDC), and the results were correlated with the expression of a costimulatory molecule upregulated upon DC maturation, CD40. METHODS: Phosphorylation of ERK1/2 (pERK1/2) and p38 MAPK (pp38 MAPK), and CD40 protein levels, were determined by Western blot. Cellular localization of pERK1/2 and pp38 MAPK were determined by immunocytochemistry using phospho-specific antibodies. RESULTS: Although with different kinetics, DNFB activated ERK1/2 and p38 MAPK, and induced the translocation of the phosphorylated forms of the kinases to the nucleus. In addition, DNFB upregulated significantly CD40 protein levels in FSDC. However, 2,4-dichloronitrobenzene (DCNB), an inactive analogue of DNFB, did not affect significantly the phosphorylation of MAPKs and CD40 protein levels. SB203580 and SB202190, inhibitors of the p38 MAPK activity, inhibited DNFB-induced CD40 upregulation, although this effect did not reach statistical significance. In contrast, PD 98059 and U0126, inhibitors of mitogen or extracellular signal-regulated kinase (MEK), had no effect on the CD40 upregulation induced by DNFB. CONCLUSIONS: Taken together, these results indicate that the strong sensitizer DNFB activates ERK1/2 and p38 MAPK signaling pathways, and upregulates CD40 protein levels. However, MAPKs do not play a major role in the induction of CD40, one of the phenotypic markers of DC maturation.
- Effect of lipopolysaccharide, skin sensitizers and irritants on thioredoxin-1 expression in dendritic cells: relevance of different signalling pathwaysPublication . Francisco, V; Neves, BM; Cruz, MT; Gonçalo, Margarida; Figueiredo, A; Duarte, CB; Lopes, MCThioredoxin-1 is a ubiquitous protein involved in phenotypical and functional changes in dendritic cells (DC). We investigated the effect of lipopolysaccharide (LPS), skin sensitizers, and irritants on thioredoxin-1 by Western blot and immunofluorescence and on mRNA by real-time PCR. As DC models, we used a skin DC line and DC derived from human blood monocytes. We observed that all tested chemicals increased thioredoxin-1 expression, which is only transient for irritants, being the strongest effect observed for LPS (63 +/- 15%). To address the involvement of thioredoxin-1 in DC maturation, we analysed the effect of an activator of thioredoxin-1 expression, hydrogen peroxide, on CD86 expression, a marker of DC maturation. We found that hydrogen peroxide increases thioredoxin-1 and CD86 expression reinforcing thioredoxin-1 involvement in DC maturation. Because mitogen-activated protein kinases and PI3K are activated upon DC maturation, we also analysed their involvement in thioredoxin-1 modulation. We verified that LPS-induced upregulation of thioredoxin-1 expression was dependent on PI3K pathway.
- Effect of skin sensitizers on inducible nitric oxide synthase expression and nitric oxide production in skin dendritic cells: role of different immunosuppressive drugsPublication . Cruz, MT; Neves, BM; Gonçalo, Margarida; Figueiredo, A; Duarte, CB; Lopes, MCNitric oxide (NO) is involved in the pathogenesis of acute and chronic inflammatory conditions, namely in allergic contact dermatitis (ACD). However, the mechanism by which NO acts in ACD remains elusive. The present study focuses on the effects of different contact sensitizers (2,4-dinitrofluorbenzene, 1,4-phenylenediamine, nickel sulfate), the inactive analogue of DNFB, 2,4-dichloronitrobenzene, and two irritants (sodium dodecyl sulphate and benzalkonium chloride) on the expression of the inducible isoform of nitric oxide synthase (iNOS) and NO production in skin dendritic cells. It was also studied the role of different immunosuppressive drugs on iNOS expression and NO production. Only nickel sulfate increased the expression of iNOS and NO production being these effects inhibited by dexamathasone. In contrast, cyclosporin A and sirolimus, two other immunosuppressive drugs tested, did not affect iNOS expression triggered by nickel.
- Expression and function of K(ATP) channels in normal and osteoarthritic human chondrocytes: Possible role in glucose sensingPublication . Rufino, AT; Rosa, SC; Judas, F; Mobasheri, A; Lopes, MC; Mendes, AF
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