Browsing by Author "Banha, J."
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- Ceruloplasmin expression by human peripheral blood lymphocytes: a new link between immunity and iron metabolismPublication . Banha, J.; Marques, L.; Oliveira, R.; Martins, M. de F.; Paixão, E.; Pereira, D.; Malhó, R.; Penque, D.; Costa, L.Ceruloplasmin (CP) is a multicopper oxidase involved in the acute phase reaction to stress. Although the physiological role of CP is uncertain, its role in iron (Fe) homeostasis and protection against free radical-initiated cell injury has been widely documented. Previous studies showed the existence of two molecular isoforms of CP: secreted CP (sCP) and a membrane glycosylphosphatidylinositol (GPI)-anchored form of CP (GPI-CP). sCP is produced mainly by the liver and is abundant in human serum whereas GPI-CP is expressed in mammalian astrocytes, rat leptomeningeal cells, and Sertolli cells. Herein, we show using RT-PCR that human peripheral blood lymphocytes (huPBL) constitutively express the transcripts for both CP molecular isoforms previously reported. Also, expression of CP in huPBL is demonstrated by immunofluorescence with confocal microscopy and flow cytometry analysis using cells isolated from healthy blood donors with normal Fe status. Importantly, the results obtained show that natural killer cells have a significantly higher CP expression compared to all other major lymphocyte subsets. In this context, the involvement of lymphocyte-derived CP on host defense processes via its anti/prooxidant properties is proposed, giving further support for a close functional interaction between the immune system and the Fe metabolism.
- Crosstalk between inflammation, iron metabolism and endothelial function in Behçet’s diseasePublication . Oliveira, R.; Napoleão, P.; Banha, J.; Paixão, E.; Bettencourt, A.; M da Silva, B.; Pereira, D.; Barcelos, F.; Teixeira, A.; Vaz Patto, J.; Viegas-Crespo, A.M.; Costa, L.Behçet's disease (BD) is a rare chronic vasculitis of unclear etiology. It has been suggested that inflammatory response has an important role in BD pathophysiology. Herein, we aimed to study the interplay between inflammation, iron metabolism and endothelial function in BD and search for its putative association with disease activity. Twenty five patients clinically diagnosed with BD were selected and twenty four healthy age-sex matched individuals participated as controls. Results showed an increase of total number of circulating white blood cells and neutrophils, serum transferrin, total iron binding capacity, mieloperoxidase (MPO), ceruloplasmin (Cp), C reactive protein, β2 microglobulin and Cp surface expression in peripheral blood monocytes in BD patients comparatively to healthy individuals (p < 0,05). Of notice, the alterations observed were associated to disease activity status. No significant differences between the two groups were found in serum nitric oxide concentration. The results obtained suggest an important contribution from innate immunity in the pathogenesis of this disease. In particular, surface expression of leukocyte-derived Cp may constitute a new and relevant biomarker to understand BD etiology.
- Differential Regulation of Ceruloplasmin Isoforms Expression in Macrophages and HepatocytesPublication . Marques, L.; Auriac, A.; Willemetz, A.; Banha, J.; Silva, B.; Canonne-Hergaux, F.; Costa, L.Ceruloplasmin (Cp) is an acute-phase protein that has been implicated in iron metabolism due to its ferroxidase activity, assisting ferroportin (Fpn) on cellular iron efflux. However, Cp exhibits both anti- and pro-oxidant activities and its physiological functions remain unclear. Cp can be expressed as a secreted or as a membrane glycosylphosphatidylinositol-anchored protein (GPI-Cp), this latter one being mostly expressed in the brain. Herein, we studied the expression of both Cp isoforms in human peripheral blood lymphocytes, monocytes, mouse macrophages and human hepatocarcinoma cell line HepG2, using immunofluorescence and immunoblotting techniques. Co-localization of Cp and Fpn was also investigated by immunofluorescence in mouse macrophages. Cp was detected by immunoblotting and immunofluorescence in membrane and cytosol of all cells types studied. The Cp detected at cell surface was identified as the GPI-isoform by PI-PLC test and shown to localize in lipid rafts in monocytes, macrophages and HepG2 cells. In macrophages, increased expression levels and co-localization of Fpn and GPI-Cp at cell surface lipid rafts were observed after iron treatment. Such upregulation of Cp by iron was not observed in HepG2 cells. Our results revealed an unexpected ubiquitous expression of the GPI-Cp isoform in immune and hepatic cells. A differential regulation of Cp in these cells may reflect distinct physiological functions of this oxidase according to cell-type specificity. In macrophages, GPI-Cp and Fpn likely interact in lipid rafts to export iron. A better insight into the expression of both Cp isoforms in different cell types will help to clarify its role in many diseases related to iron metabolism, inflammation and oxidative biology.
- Immune cells and hepatocytes express glycosylphosphatidylinositol-anchored ceruloplasmin at their cell surfacePublication . Marques, L.; Auriac, A.; Willemetz, A.; Banha, J.; Silva, B.; Canonne-Hergaux, F.; Costa, L.Ceruloplasmin is a positive acute-phase protein with both anti- and pro-oxidant activities, thus having still unclear physiological functions in inflammatory processes. Importantly, ceruloplasmin has been implicated in iron metabolism due to its ferroxidase activity, assisting ferroportin on cellular iron efflux. Ceruloplasmin can be expressed as a secreted or as a membrane glycosylphosphatidylinositol-anchored protein (GPI-ceruloplasmin), this latter one being reported as expressed mostly in the brain.
- Immune cells and hepatocytes express glycosylphosphatidylinositol-anchored ceruloplasmin at their cell surfacePublication . Marques, L.; Auriac, A.; Willemetz, A.; Banha, J.; Silva, B.; Canonne-Hergaux, F.; Costa, L.Ceruloplasmin is a positive acute-phase protein with both anti- and pro-oxidant activities, thus having still unclear physiological functions in inflammatory processes. Importantly, ceruloplasmin has been implicated in iron metabolism due to its ferroxidase activity, assisting ferroportin on cellular iron efflux. Ceruloplasmin can be expressed as a secreted or as a membrane glycosylphosphatidylinositol-anchored protein (GPI-ceruloplasmin), this latter one being reported as expressed mostly in the brain.
- Inflammatory stimuli modulates the expression of ceruloplasmin at surface of human peripheral blood mononuclear cellsPublication . Bispo, C.; Villares, A.; Banha, J.; Marques, L.; Costa, L.Atherosclerosis (ATH) is recognized as a chronic inflammatory condition and it is the leading cause of cardiovascular disease. Atherogenesis is characterized by the passage of LDL through the endothelial layer, and the early infiltration and activation of peripheral blood lymphocytes (PBL) and monocytes (PBMN) that contribute to a pro-inflammatory state in specific locations. However, the functional interaction between immune cells and the oxidation of LDL are still not fully understood. One hypothesis for the etiopathogeny of ATH may be associated with an ongoing inflammatory process caused by an pro-oxidant/antioxidant imbalance induced by metals such as iron (Fe) or copper (Cu). Ceruloplasmin (Cp) is an acute-phase protein but also a multicopper oxidase with a relevant role in Fe metabolism mainly due to its ferroxidase activity. Herein, we aim to study the effect of putative pro-atherogenic immune stimuli on the expression of Cp at the surface of peripheral blood mononuclear cells (PBMC). In order to achieve this goal, PBMC were isolated from human peripheral blood, cultured in different inflammatory and/or altered Fe/Cu status conditions and analysis of Cp expression at cell surface was performed using flow cytometry. Cell surface expression of Cp was shown to be differently modulated by several tested treatments. Importantly, PBMN incubated with IL-1β showed a significant increase of Cp expression compared to untreated cells. Similar results were found using phorbol-12-myristate-13-acetate. Also, higher cell surface expression of Cp was consistently observed in PBMN compared to PBL and in activated vs non-activated cells. These results demonstrate that inflammatory mediators could be, at least in part, involved in the modulation of Cp expression at surface of PBMC and thus, have a putative role in atherogenesis.
- Lymphocyte ceruloplasmin and Behçet's diseasePublication . Oliveira, R.; Banha, J.; Martins, F.; Paixão, E.; Pereira, D.; Barcelos, F.; Teixeira, A.; Patto, J.V.; Costa, L.Behçet's disease (BD) is a rare chronic inflammatory disorder of unknown aetiology. However, it has been postulated that a dysregulation of the prooxidant/antioxidant balance may be important to its pathogenesis. Ceruloplasmin (CP) is an acute phase protein expressed at the surface of peripheral blood lymphocytes (PBL) with antioxidant properties and with a relevant role in iron (Fe) metabolism.