Browsing by Author "Costa, Paulo P."
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- Brain expression of inflammatory mediators in Mesial Temporal Lobe Epilepsy patientsPublication . Leal, Bárbara; Chaves, João; Carvalho, Cláudia; Rangel, Rui; Santos, Agostinho; Bettencourt, Andreia; Lopes, João; Ramalheira, João; Silva, Berta M.; da Silva, António Martins; Costa, Paulo P.Neuroinflammation may be central in epileptogenesis. In this study we analysed inflammatory reaction markers in brain tissue of Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) patients. TLR4, IL-1β and IL-10 gene expression as well as the presence of activated HLA-DR+ microglia was evaluated in 23 patients and 10 cadaveric controls. Inflammation characterized by the presence of HLA-DR+microglia and TLR4, IL-1β overexpression was evident in hippocampus and anterior temporal cortex of MTLE-HS patients. Anti-inflammatory IL-10 was also overexpressed in MTLE-HS patients. Our results show that hippocampal neuroinflammation extends beyond lesional limits, as far as the anterior temporal cortex.
- Evolutionary Insights into IL17A in LagomorphsPublication . Neves, Fabiana; Abrantes, Joana; Almeida, Tereza; Costa, Paulo P.; Esteves, Pedro J.In leporids, IL17A had been implicated in the host defense against extracellular pathogens, such as Francisella tularensis that infects hares and rabbits and causes the zoonotic disease tularemia. Here, we studied IL17A from five lagomorphs, European rabbit, pygmy rabbit, brush rabbit, European brown hare, and American pika. We observed that this protein is highly conserved between these species, with a similarity of 97-99% in leporids and ~88% between leporids and American pika. The exon/intron structure, N-glycosylation sites, and cysteine residues are conserved between lagomorphs. However, at codon 88, one of the interaction sites between IL17A and its receptor IL17RA, there is an Arg>Pro mutation that only occurs in European rabbit and European brown hare. This could induce critical alterations in the IL17A structure and conformation and consequently modify its function. The differences observed between leporids and humans or rodents might also represent important alterations in protein structure and function. In addition, as for other interleukins, IL17A sequences of human and European rabbit are more closely related than the sequences of human and mouse or European rabbit and mouse. This study gives further support to the hypothesis that European rabbit might be a more suitable animal model for studies on human IL17.
- Expression of Inflammation-Associated MicroRNAs in EpilepsyPublication . Leal, Bárbara; Carvalho, Cláudia; Chaves, João; Bettencourt, Andreia; Freitas, Joel; Lopes, João; Ramalheira, João; Silva, António M.; Costa, Paulo P.; Silva, Berta M.Background: Neuroinflammation appears as an important epileptogenic mechanism. MicroRNAs (miRNA) are small non-coding RNA molecules that function as post-transcriptional regulators of gene expression, controlling different biological process including immune system homeostasis and function. Evidences, both in patients and animal studies, have demonstrated an abnormal brain expression of miR-146a and miR-155 in Mesial Temporal Lobe Epilepsy (MTLE), the most refractory epilepsy type. Knowing that miR expression is very stable in biological fluids such as plasma or serum our aim was to characterize miR-146a and miR-155 expression in serum of MTLE and GGE patients. Methods: Expression levels of miR146a and RNU48 (reference gene) were quantified by Real-Time PCR in serum of 16 MTLE patients all with Hippocampal Sclerosis (6F, 8M, mean age= 44.1±11.7 years, age of onset= 13.5±10.6 years, 7 with Febrile Seizures antecedents). A group of 24 healthy individuals was used as control. Relative expression values were calculated using the 2-ΔΔCt method. Results: MTLE patients had a higher expression of miR-146a (6 fold) and miR-155 (2 fold) when compared to controls. Conclusion: Our results, although preliminary, show that miR-146a and miR-155 may be suitable biomarkers for epileptogenesis. It is thought that these miRNAs have role in fine-tuning the response to pro-inflammatory cytokines during epileptogenesis. Nevertheless its importance in epilepsy development it is yet not fully understood. The comprehension of this role may be relevant for the development of new therapeutic strategies.
- Mesial Temporal Lobe Epilepsy (MTLE) Drug-Refractoriness Is Associated With P2X7 Receptors Overexpression in the Human Hippocampus and Temporal Neocortex and May Be Predicted by Low Circulating Levels of miR-22Publication . Guerra Leal, Bárbara; Barros-Barbosa, Aurora; Ferreirinha, Fátima; Chaves, João; Rangel, Rui; Santos, Agostinho; Carvalho, Cláudia; Martins-Ferreira, Ricardo; Samões, Raquel; Freitas, Joel; Lopes, João; Ramalheira, João; Lobo, Maria Graça; Martins da Silva, António; Costa, Paulo P.; Correia-de-Sá, PauloObjective: ATP-gated ionotropic P2X7 receptors (P2X7R) actively participate in epilepsy and other neurological disorders. Neocortical nerve terminals of patients with Mesial Temporal Lobe Epilepsy with Hippocampal Sclerosis (MTLE-HS) express higher P2X7R amounts. Overexpression of P2X7R bolsters ATP signals during seizures resulting in glial cell activation, cytokines production, and GABAergic rundown with unrestrained glutamatergic excitation. In a mouse model of status epilepticus, increased expression of P2X7R has been associated with the down-modulation of the non-coding micro RNA, miR-22. MiR levels are stable in biological fluids and normally reflect remote tissue production making them ideal disease biomarkers. Here, we compared P2X7R and miR-22 expression in epileptic brains and in the serum of patients with MTLE-HS, respectively. Methods: Quantitative RT-PCR was used to evaluate the expression of P2X7R in the hippocampus and anterior temporal lobe of 23 patients with MTLE-HS and 10 cadaveric controls. Confocal microscopy and Western blot analysis were performed to assess P2X7R protein amounts. MiR-22 expression was evaluated in cell-free sera of 40 MTLE-HS patients and 48 healthy controls. Results: Nerve terminals of the hippocampus and neocortical temporal lobe of MTLE-HS patients overexpress (p < 0.05) an 85 kDa P2X7R protein whereas the normally occurring 67 kDa receptor protein dominates in the brain of the cadaveric controls. Contrariwise, miR-22 serum levels are diminished (p < 0.001) in MTLE-HS patients compared to age-matched control blood donors, a situation that is more evident in patients requiring multiple (>3) anti-epileptic drug (AED) regimens. Conclusion: Data show that there is an inverse relationship between miR-22 serum levels and P2X7R expression in the hippocampus and neocortex of MTLE-HS patients, which implies that measuring serum miR-22 may be a clinical surrogate of P2X7R brain expression in the MTLE-HS. Moreover, the high area under the ROC curve (0.777; 95% CI 0.629-0.925; p = 0.001) suggests that low miR-22 serum levels may be a sensitive predictor of poor response to AEDs among MTLE-HS patients. Results also anticipate that targeting the miR-22/P2X7R axis may be a good strategy to develop newer AEDs.
- Oligomeric TTR V30M aggregates compromise cell viability, erythropoietin gene expression and promoter activity in the human hepatoma cell line Hep3BPublication . Moreira, Luciana V.; Beirão, João M.; Beirão, Idalina; Costa, Paulo P.Familial amyloidotic polyneuropathy, ATTRV30M (p. TTRV50M) amyloidosis, is a neurodegenerative disease characterized by systemic extracellular amyloid deposition of a mutant transthyretin, TTR V30M. Anemia, with low erythropoietin (EPO) levels and spared kidney function, affects about 25% of symptomatic patients, suggesting a blockage of EPO-producing cells. Early non-fibrillar TTR aggregates are highly cytotoxic, inducing oxidative stress, the expression of apoptosis-related molecules and secretion of pro-inflammatory cytokines, factors capable of inhibiting EPO production. Low EPO levels in these patients are not related to renal amyloid deposition or the presence of circulating TTR V30M. However, the role of early non-fibrillar TTR aggregates remains unexplored. We used the EPO producing Hep3B human hepatoma cell line to study the effect of TTR oligomeric aggregates on EPO expression. Hep3B cells were incubated with soluble and oligomeric TTR V30M, and cell proliferation as well as caspase 3/7 activation was evaluated. Relative quantification of EPO mRNA transcripts was performed by real-time PCR. Significant reductions in cell viability (13 ± 7.3%) and activation of caspases 3/7 were seen after 24 h in the presence of oligomeric TTR V30M. Also, EPO expression was significantly reduced (50 ± 2.8%), in normoxic conditions. A reporter assay was constructed with a PCR fragment of the EPO promoter linked to the luciferase gene to evaluate the role of transcription factors targeting the promoter. A significant reduction of EPO promoter activity (53 ± 6.5%) was observed in transfected cells exposed to TTR oligomers. Our results show that oligomeric TTR V30M reduces EPO expression, at least in part through inhibition of promoter activity.
- The Protective Role of HLA-DRB1(*)13 in Autoimmune DiseasesPublication . Bettencourt, Andreia; Carvalho, Cláudia; Leal, Bárbara; Brás, Sandra; Lopes, Dina; Martins da Silva, Ana; Santos, Ernestina; Torres, Tiago; Almeida, Isabel; Farinha, Fátima; Barbosa, Paulo; Marinho, António; Selores, Manuela; Correia, João; Vasconcelos, Carlos; Costa, Paulo P.; da Silva, Berta MartinsAutoimmune diseases (AIDs) are characterized by a multifactorial aetiology and a complex genetic background, with the MHC region playing a major role. We genotyped for HLA-DRB1 locus 1228 patients with AIDs-213 with Systemic Lupus Erythematosus (SLE), 166 with Psoriasis or Psoriatic Arthritis (Ps + PsA), 153 with Rheumatoid Arthritis (RA), 67 with Systemic Sclerosis (SSc), 536 with Multiple Sclerosis (MS), and 93 with Myasthenia Gravis (MG) and 282 unrelated controls. We confirmed previously established associations of HLA-DRB1(∗)15 (OR = 2.17) and HLA-DRB1(∗)03 (OR = 1.81) alleles with MS, HLA-DRB1(∗)03 with SLE (OR = 2.49), HLA-DRB1(∗)01 (OR = 1.79) and HLA-DRB1(∗)04 (OR = 2.81) with RA, HLA-DRB1(∗)07 with Ps + PsA (OR = 1.79), HLA-DRB1(∗)01 (OR = 2.28) and HLA-DRB1(∗)08 (OR = 3.01) with SSc, and HLA-DRB1(∗)03 with MG (OR = 2.98). We further observed a consistent negative association of HLA-DRB1(∗)13 allele with SLE, Ps + PsA, RA, and SSc (18.3%, 19.3%, 16.3%, and 11.9%, resp., versus 29.8% in controls). HLA-DRB1(∗)13 frequency in the AIDs group was 20.0% (OR = 0.58). Although different alleles were associated with particular AIDs, the same allele, HLA-DRB1(∗)13, was underrepresented in all of the six diseases analysed. This observation suggests that this allele may confer protection for AIDs, particularly for systemic and rheumatic disease. The protective effect of HLA-DRB1(∗)13 could be explained by a more proficient antigen presentation by these molecules, favouring efficient clonal deletion during thymic selection.
- Use of MALDI-TOF Mass Spectrometry to Assay the Transthyretin V30M Mutation in Serum From a Liver Transplant DonorPublication . Lacerda, Pedro C.; Moreira, Luciana; Vitorino, Rui; Costa, Paulo P.Familial amyloidotic polyneuropathy (FAP), Portuguese type, or ATTR V30M is an autosomal dominant inherited disorder caused by a mutation in the transthyretin gene, with a valine/methionine substitution at position 30 (TTRV30M). ATTRV30Mis characterized by a progressive sensory/autonomic polyneuropathy and multiple organ dysfunction. Liver transplantation is the main therapeutic option,as it virtually eliminates the production of circulating TTR V30M, which occurs predominantly in the liver.
- Vitamin D supplementation effects on FoxP3 expression in T cells and FoxP3+/IL-17A ratio and clinical course in systemic lupus erythematosus patients: a study in a Portuguese cohortPublication . Marinho, António; Carvalho, Cláudia; Boleixa, Daniela; Bettencourt, Andreia; Leal, Bárbara; Guimarães, Judite; Neves, Esmeralda; Oliveira, José Carlos; Almeida, Isabel; Farinha, Fátima; Costa, Paulo P.; Vasconcelos, Carlos; Silva, Berta M.Systemic lupus erythematosus (SLE) is a systemic autoimmune disease with multi-organ inflammation, linked to loss of immune tolerance to self-antigens and the production of a diversity of autoantibodies, with a negative impact on the patients' quality of life. Regulatory T cells have been reported as deficient in number and function in SLE patients. However, some authors also described an enrichment of this cell type. The hypothesis that certain forms of autoimmunity may result from a conversion of Treg cells into a Th17 cell phenotype has been suggested by some studies. In fact, in SLE patients' sera, the IL-17 levels were observed as abnormally high when compared with healthy individuals. Environmental factors, such as vitamin D, that is considered a potential anti-inflammatory agent, combined with genetic and hormonal characteristics have been associated with SLE phenotype and with disease progression. The aim of this study was to evaluate the effect of vitamin D supplementation on FoxP3 expression and IL-17A-producing T cells, through FoxP3+/IL-17A ratio. Additionally, disease evolution, serum vitamin D levels, serum autoantibodies levels and calcium metabolism (to assure safety) were also studied. We assessed 24 phenotypically well-characterized SLE patients. All patients were screened before vitamin D supplementation and 3 and 6 months after the beginning of this treatment. Peripheral blood lymphocyte's subsets were analysed by flow cytometry. Serum 25(OH)D levels significantly increased under vitamin D supplementation (p = 0.001). The FoxP3+/IL-17A ratio in SLE patients after 6 months of vitamin D supplementation was higher than that in the baseline (p < 0.001). In conclusion, this study demonstrated that vitamin D supplementation provided favourable, immunological and clinical impact on SLE.