Browsing by Author "Oliveira, Sofia A."
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- Convergence of miRNA expression profiling, α-synuclein interacton and GWAS in Parkinson's diseasePublication . Martins, Madalena; Rosa, Alexandra; Guedes, Leonor C.; Fonseca, Benedita V.; Gotovac, Kristina; Violante, Sara; Mestre, Tiago; Coelho, Miguel; Rosa, Mário M.; Martin, Eden R.; Vance, Jeffery M.; Outeiro, Tiago F.; Wang, Liyong; Borovecki, Fran; Ferreira, Joaquim J.; Oliveira, Sofia A.miRNAs were recently implicated in the pathogenesis of numerous diseases, including neurological disorders such as Parkinson’s disease (PD). miRNAs are abundant in the nervous system, essential for efficient brain function and play important roles in neuronal patterning and cell specification. To further investigate their involvement in the etiology of PD, we conducted miRNA expression profiling in peripheral blood mononuclear cells (PBMCs) of 19 patients and 13 controls using microarrays. We found 18 miRNAs differentially expressed, and pathway analysis of 662 predicted target genes of 11 of these miRNAs revealed an over-representation in pathways previously linked to PD as well as novel pathways. To narrow down the genes for further investigations, we undertook a parallel approach using chromatin immunoprecipitation-sequencing (ChIP-seq) analysis to uncover genome-wide interactions of a-synuclein, a molecule with a central role in both monogenic and idiopathic PD. Convergence of ChIP-seq and miRNomics data highlighted the glycosphingolipid biosynthesis and the ubiquitin proteasome system as key players in PD. We then tested the association of target genes belonging to these pathways with PD risk, and identified nine SNPs in USP37 consistently associated with PD susceptibility in three genome-wide association studies (GWAS) datasets (0.46#OR#0.63) and highly significant in the meta-dataset (3.3661024 ,p,1.9461023 ). A SNP in ST8SIA4 was also highly associated with PD (p = 6.1561023 ) in the meta-dataset. These findings suggest that several miRNAs may act as regulators of both known and novel biological processes leading to idiopathic PD.
- Mitochondrial genome association study with peripheral arterial disease and venous thromboembolismPublication . Abrantes, Patrícia; Rosa, Alexandra; Francisco, Vânia; Sousa, Inês; Xavier, Joana M.; Oliveira, Sofia A.Background and aims: Peripheral arterial disease (PAD) and venous thromboembolism (VTE) are vascular traits sharing common modifiable and non-modifiable risk factors. These vascular pathologies have known nuclear-encoded genetic risk factors and the mitochondrial DNA may account for part of the missing heritability. To determine if PAD and VTE have a dual genetic control (mitochondrial and nu clear), we hereby investigated the association of mitochondrial DNA polymorphisms and haplogroups with these vascular traits. Methods: The association of mitochondrial single nucleotide polymorphisms (mtSNPs) and haplogroups was tested in 1652 PAD cases and 1629 controls from the eMERGE PAD genome-wide association study (GWAS), and 1241 VTE cases and 1278 controls from the GENEVA GWAS of venous thrombosis (dbGaP accession numbers phs000203.v1.p1 and phs000289.v2.p1, respectively). Results: 66 and 72 mtSNPs passed quality control filters and were tested for association with PAD and VTE, respectively. Significant evidence of population stratification could not be detected in both datasets. Three mtSNPs (m.477T > C, m.9667A > G, and m.10915T > C) were nominally associated (3.01 10 3 pa 3.96 10 2 ) with PAD in the logistic regression adjusted for confounding factors, and m.11914G > A was nominally associated (pa ¼ 4.14 10 2 ) with VTE. None of the nine major mito chondrial haplogroups were associated with either PAD or VTE. Conclusion: Unlike other vascular diseases such as stroke and diabetes, these results suggest that com mon mitochondrial variants individually or in combination do not play a major role in PAD and VTE susceptibility.
- Mitochondrial haplogroup H1 is protective for ischemic stroke in portuguese patientsPublication . Rosa, Alexandra; Fonseca, Benedita V.; Krug, Tiago; Manso, Helena; Gouveia, Liliana; Albergaria, Isabel; Gaspar, Gisela; Correia, Manuel; Viana-Baptista, Miguel; Simões, Rita Moiron; Pinto, Amélia Nogueira; Taipa, Ricardo; Ferreira, Carla; Fontes, João Ramalho; Silva, Mário Rui; Gabriel, João Paulo; Matos, Ilda; Lopes, Gabriela; Ferro, José M; Vicente, Astrid M; Oliveira, Sofia A.Background: The genetic contribution to stroke is well established but it has proven difficult to identify the genes and the disease-associated alleles mediating this effect, possibly because only nuclear genes have been intensely investigated so far. Mitochondrial DNA (mtDNA) has been implicated in several disorders having stroke as one of its clinical manifestations. The aim of this case-control study was to assess the contribution of mtDNA polymorphisms and haplogroups to ischemic stroke risk. Methods: We genotyped 19 mtDNA single nucleotide polymorphisms (SNPs) defining the major European haplogroups in 534 ischemic stroke patients and 499 controls collected in Portugal, and tested their allelic and haplogroup association with ischemic stroke risk. Results: Haplogroup H1 was found to be significantly less frequent in stroke patients than in controls (OR = 0.61, 95% CI = 0.45–0.83, p = 0.001), when comparing each clade against all other haplogroups pooled together. Conversely, the pre-HV/HV and U mtDNA lineages emerge as potential genetic factors conferring risk for stroke (OR = 3.14, 95% CI = 1.41–7.01, p = 0.003, and OR = 2.87, 95% CI = 1.13–7.28, p = 0.021, respectively). SNPs m.3010G>A, m.7028C>T and m.11719G>A strongly influence ischemic stroke risk, their allelic state in haplogroup H1 corroborating its protective effect. Conclusion: Our data suggests that mitochondrial haplogroup H1 has an impact on ischemic stroke risk in a Portuguese sample
- Ulcerative colitis is under dual (mitochondrial and nuclear) genetic controlPublication . Rosa, Alexandra; Abrantes, Patrícia; Sousa, Inês; Francisco, Vânia; Santos, Patrícia; Francisco, David; Xavier, Joana M.; Oliveira, Sofia A.Background: Cellular oxidative stress and genetic susceptibility have been implicated in the multifactorial etiology of ulcerative colitis (UC). The nuclear genome association with UC has been intensely investigated, but the role of the mitochondrial DNA (mtDNA) has received far less attention and may account for part of the missing heritability. This study is a comprehensive analysis of the mtDNA contribution to UC susceptibility. Methods: The association of mitochondrial single-nucleotide polymorphisms (mtSNPs) and haplogroups with UC was tested in 488 cases and 833 controls of European ancestry from the NIDDK IBD Genetics Consortium Ulcerative Colitis Genome-Wide Association Study available through dbGaP and from the Illumina Genotype Control Database (studies 64 and 65). Results: No evidence of population stratification could be detected using 218 ancestry informative markers for European Americans. Seven of the 58 tested mtSNPs were nominally associated with UC, and A10550G in MT-ND4L withstands the Bonferroni correction (P ¼ 1.29E-06, odds ratio [ORG] [95% confidence interval (CI)] ¼ 4.80 [2.54–9.05], 10550G allele: 8.1% of patients and 1.9% of controls). A10550G remains equally associated after conditional analyses on the 11 UC genome-wide association studies (GWAS) top SNPs (6.35E-07 , Pcond , 4.58E-06), which suggests that it constitutes an independent risk factor from nuclear-encoded susceptibility loci. We detected additive (but not multiplicative) epistatic interactions between A10550G and all 11 top GWAS hits. Subhaplogroup K1 (P ¼ 0.021, OR [95% CI] ¼ 1.71 [1.08–2.69]) increased the risk for UC, whereas the U5b lineage conferred protection (P ¼ 0.016, OR [95% CI] ¼ 0.34 [0.14–0.82]). Conclusions: These results suggest that UC has a dual mitochondrial and nuclear genetic control that warrants further replication in independent data sets and reinforces its etiopathogenic complexity.