DGH - Artigos em revistas internacionais
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- Estrogen-mediated inhibition of purine metabolism and cell cycle arrest as a novel therapeutic approach in colorectal cancerPublication . Zamer, Batoul Abi; Shafarin, Jasmin; Sharaf, BasmaM.; Hroub, HamzaM. Al; Soares, Nelson C.; Semreen, Mohammad H.; Hamad, Mawieh; Muhammad, Jibran SualehPurine metabolism is upregulated in various cancers including colorectal cancer (CRC). While previous work has elucidated the role of estrogen (E2) in metabolic reprogramming and ATP production, the effect of E2 on purine metabolism remains largely unknown. Herein, the impact of E2 signalling on purine metabolism in CRC cells was investigated using metabolome and transcriptome profiling of cell extracts derived from E2-treated HCT-116 cells with intact or silenced estrogen receptor alpha (ERα). Purine metabolic pathway enrichment analysis showed that 27 genes in the de novo purine synthesis pathway were downregulated in E2-treated CRC cells. Downstream consequences of E2 treatment including the induction of DNA damage, cell cycle arrest, and apoptosis were all shown to be ERα-dependent. These findings demonstrate, for the first time, that E2 exerts a significant anti-growth and survival effect in CRC cells by targeting the purine synthesis pathway in a ERα-dependent manner, meriting further investigation of the therapeutic utility of E2 signalling in CRC.
- Type 1 Gaucher Disease: Identification of and Prevalence of Glucocerebrosidase Mutations in the PortuguesePublication . Amaral, Olga; Pinto, Eugénia; Fortuna, Margarida; La cerda, Lucia; Sá Miranda, M.C.
- Distinct Haplotype in Non-Ashkenazi Gaucher Patients with N370S MutationPublication . Amaral, Olga; Marcao, Ana; Pinto, Eugénia; Zimran, Ari; Sá Miranda, M.C.A new polymorphism, in intron 7 of glucocerebrosidase gene, has been identified in Gaucher Disease patients. It seems to appear only in Pv1.1- alleles bearing the N370S mutation. This new sub-haplotype was only identified in Portuguese patients, of origins spanning all of the Portuguese continental territory. This finding indicates that, in the Portuguese, mutation N370S has existed in the context of two slightly different haplotypes and thus must be relatively ancient.
- Gaucher disease: expression and characterization of mild and severe acid beta-glucosidase mutations in Portuguese type 1 patientsPublication . Amaral, O.; Marcão, A.; Sá Miranda, M.; Desnick, R.J.; Grace, M.E.Type 1 Gaucher disease (GD), the most prevalent lysosomal storage disease, results from the deficient activity of acid alpha-glucosidase. Molecular analysis of 12 unrelated Portuguese patients with type 1 GD identified three novel acid â-glucosidase mutations (F109V, W184R and R395P), as well as three previously reported, but uncharacterized, lesions (R359Q, G377S and N396T). The type 1 probands were either heteroallelic for the well-characterized common lesion, N370S, and the F109V, W184R, R359Q or N396T lesions or homoallelic for the G377S or N396T mutations. Expression of the W184R, R359Q, and R395P mutations revealed very low specific activities based on cross-reacting immunologic material (CRIM SAs of 0.0004, 0.016 and 0.045, respectively), consistent with their being found only in type 1 patients who had a neuroprotective N370S allele. In contrast, the F109V, G377S and N396T alleles had significant acid â-glucosidase activity (CRIM specific activities of 0.15, 0.17, 0.14, respectively), in agreement with their being mild type 1 alleles. Thus, these studies identified additional acid â-glucosidase mutations in the Portuguese population and demonstrated that the G377S and N396T mutations were neuroprotective, consistent with the mild clinical phenotypes of the type 1 patients who were homoallelic for the G377S and N396T lesions.
- Gaucher disease: the origins of the Ashkenazi Jewish N370S and 84GG acid beta-glucosidase mutationsPublication . Diaz, G.A.; Gelb, B.D.; Risch, N.; Nygaard, T.G.; Frisch, A.; Cohen, I.J.; Miranda, C.S.; Amaral, O.; Maire, I.; Poenaru, L.; Caillaud, C.; Weizberg, M.; Mistry, P.; Desnick, R.J.Type 1 Gaucher disease (GD), a non-neuronopathic lysosomal storage disorder, results from the deficient activity of acid beta-glucosidase (GBA). Type 1 disease is panethnic but is more prevalent in individuals of Ashkenazi Jewish (AJ) descent. Of the causative GBA mutations, N370S is particularly frequent in the AJ population, (q approximately .03), whereas the 84GG insertion (q approximately .003) occurs exclusively in the Ashkenazim. To investigate the genetic history of these mutations in the AJ population, short tandem repeat (STR) markers were used to map a 9.3-cM region containing the GBA locus and to genotype 261 AJ N370S chromosomes, 60 European non-Jewish N370S chromosomes, and 62 AJ 84GG chromosomes. A highly conserved haplotype at four markers flanking GBA (PKLR, D1S1595, D1S2721, and D1S2777) was observed on both the AJ chromosomes and the non-Jewish N370S chromosomes, suggesting the occurrence of a founder common to both populations. Of note, the presence of different divergent haplotypes suggested the occurrence of de novo, recurrent N370S mutations. In contrast, a different conserved haplotype at these markers was identified on the 84GG chromosomes, which was unique to the AJ population. On the basis of the linkage disequilibrium (LD) delta values, the non-Jewish European N370S chromosomes had greater haplotype diversity and less LD at the markers flanking the conserved haplotype than did the AJ N370S chromosomes. This finding is consistent with the presence of the N370S mutation in the non-Jewish European population prior to the founding of the AJ population. Coalescence analyses for the N370S and 84GG mutations estimated similar coalescence times, of 48 and 55.5 generations ago, respectively. The results of these studies are consistent with a significant bottleneck occurring in the AJ population during the first millennium, when the population became established in Europe.
- Niemann-Pick type C disease: NPC1 mutations associated with severe and mild cellular cholesterol trafficking alterationsPublication . Ribeiro, Isaura; Marcao, Ana; Amaral, Olga; Sá Miranda, M.C,; Vanier, M.T,; Millat, GillesNiemann-Pick type C disease (NPC) is a rare neurodegenerative disorder characterised by lysosomal/late endosomal accumulation of endocytosed unesterified cholesterol and delayed induction of cholesterol homeostatic reactions. The large majority of mutations in the NPC1 gene described thus far have been associated with severe cellular cholesterol trafficking impairment (classic biochemical phenotype, present in about 85% of NPC patients). In our population of 13 unrelated NP-C1 patients, among which 12 were of Portuguese extraction, we observed an unusually large proportion of families presenting mild alterations of intracellular cholesterol transport (variant biochemical phenotype), without strict correlation between the biochemical phenotype and the clinical expression of the disease. Mutational studies were carried out to compare molecular lesions associated with severe and mild cholesterol traffic impairment. Levels of NPC1 protein were studied by Western blot in cultured fibroblasts of four patients with homozygous mutant alleles. Ten novel mutations were identified (Q92R, C177Y, R518W, W942C, R978C, A1035V, 2129delA, 3662delT, IVS23+1 G>A and IVS16-82 G>A). The mutational profile appeared to be correlated with the biochemical phenotype. Splicing mutations, I1061T and A1035V, corresponded to "classic" alleles, while three missense mutations, C177Y, R978C and P1007A, could be defined as "variant" alleles. All "variant" mutations described so far appear to be clustered within the cysteine-rich luminal loop between TM 8 and 9, with the remarkable exception of C177Y. The latter mutant allele, at variance with P1007A, was correlated to a decreased level of NPC1 protein and a severe course of the disease, and disclosed a new location for "variant" mutations, the luminal loop located at the N-terminal end of the protein.
- Adult-onset neuronopathic form of Gaucher's disease: a case reportPublication . Guimarães, J.; Amaral, O.; Sá Miranda, M.C.We report a patient with Gaucher's disease (GD) developing prominent neurological abnormalities in adult life confirming the existence of an adult neuronopathic form of GD. In this adult-onset form, an akinetic-rigid syndrome poorly responsive to dopatherapy, supranuclear gaze palsy, myoclonic jerks, seizures, cerebellar ataxia, cognitive and psychotic disturbances are frequent manifestations. The widely used clinical classification seems inadequate since it does not consider this rare form of GD. Until further understanding of the pathogenesis of the disease is achieved it is not possible to predict accurately which patients will or will not have late-onset nervous system involvement.
- Allelic frequency determination of the 24-bp chitotriosidase duplication in the Portuguese population by real-time PCRPublication . Rodrigues, M.R.; Sá Miranda, M.C.; Amaral, O.Chitotriosidase is a human chitinase produced by macrophages. Its enzymatic activity is markedly elevated in serum of patients suffering from lysosomal storage disorders, as well as other diseases in which macrophages are activated. Therefore, it is a useful tool as a secondary marker in the diagnosis of several disorders including Gaucher disease type 1 and Niemann–Pick disease. The determination of chitotriosidase levels as a diagnosis complement in some lysosomal storage disorders and in enzyme replacement therapy follow-up of Gaucher disease patients is of great importance. However, the fact that a mutation caused by a 24-bp duplication in the CHIT1 gene resulting in deficiency of plasma chitotriosidase activity is very frequent makes the establishment of the frequency of this mutation in different population groups necessary. Furthermore, in order to validate the use of chitotriosidase activity as a marker, it is indispensable to screen individuals for this particular mutation. In this work, we present the results of a study where the allelic frequency of the abovementioned CHIT1 gene mutation was determined in the Portuguese population by real-time PCR. The frequency of carriers encountered in this sample of Portuguese individuals was of 37%.
- Mutations c.459+1G>A and p.P426L in the ARSA gene: prevalence in metachromatic leukodystrophy patients from European countriesPublication . Lugowska, A.; Amaral, O.; Berger, J.; Berna, L.; Bosshard, N.; Chabas, A.; Fensom, A.; Gieselmann, V.; Gorovenko, N.; Lissens, W.; Mansson, J.; Marcao, A.; Michelakakis, H.; Bernheimer, H.; Ol'khovych, N.; Regis, S.; Sinke, R.; Tylki-Szymanska, A.; Czartoryska, B.In this multicentre study, we examined the prevalence of two mutations in the arylsulfatase A (ARSA) gene, i.e., c.459 + 1G > A and p.P426L, in 384 unrelated European patients presenting with different types of metachromatic leukodystrophy (MLD). In total, c.459 + 1G > A was found 194 times among the 768 investigated ARSA alleles (25%), whereas p.P426L was identified 143 times (18.6%). Thus, these two mutations accounted for 43.8% of investigated MLD alleles. Mutation c.459 + 1G > A was most frequent in late-infantile MLD patients (40%), while p.P426L was most frequent in adults (42.5%), which is consistent with earlier observations, although p.P426L was also found in a few late-infantile patients (0.9%), and c.459 + 1G > A was present in some adults (9%). Mutation c.459 + 1G > A is more frequent in countries situated at the western edges of Europe, i.e., in Great Britain and Portugal, and also in Belgium, Switzerland, and Italy, which is visible as a strand ranging from North to South, and additionally in Czech and Slovak Republics. Mutation p.P426L is most prevalent in countries assembled in a cluster containing the Netherlands, Germany, and Austria. In other Central European countries, the frequency of both c.459 + 1G > A and p.P426L ranges from 8 to 37.5%. Our study has confirmed that c.459 + 1G > A and p.P426L are the most frequently found MLD-causing mutations in Europe. The data about their prevalence reflect the population variability in Europe.
- Mutation spectrum of Gaucher disease in Tunisia: high frequency of N370S/Rec NciI compound heterozygousPublication . Cherif, W.; Ben Turkia, H.; Tebib, N.; Amaral, O.; Ben Rhouma, F.; Abdelmoula MS, M.S.; Azzouz, H.; Caillaud, C.; Sà Miranda, M.C.; Abdelhak, S.; Ben Dridi, M.F.Gaucher disease is the most common lysosomal storage disorder, it results from the inherited deficiency of the enzyme glucocerebrosidase, the accumulation of its substrate causes many clinical manifestations. Since the discovery of GBA gene, more than 200 different mutations have been identified, but only handful mutations are recurrent (N370S, L444P and c.84insG). In order to determine the mutation spectrum in Tunisia, we performed recurrent mutation screening in ten unrelated Tunisian children with Gaucher disease. Screening of recurrent mutation by PCR/RFLP and direct sequencing, has shown that N370S is the most frequent mutation (6/20 mutant alleles, 30%), followed by recombinant allele (RecNciI) which is found in five patients (5/20 mutant alleles, 25%), the L444P mutation represent 20% (4/20 mutant alleles). Our findings revealed that five among ten studied patients, were compound heterozygous N370S/RecNciI (50%). The screening of these mutations provides a simple tool for molecular diagnosis of Gaucher disease in Tunisian patients and allows also genetic counselling for their family members.