Analysis of the association of polymorphism in the osteoprotegerin gene with susceptibility to chronic kidney disease and periodontitis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

The 844ins68 cystathionine beta-synthase and C677T MTHFR gene polymorphism and the vaso-occlusive event risk in sickle cell disease

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Comparison of oxidative stress and the frequency of polymorphisms in the HFE gene between hemoglobin S trait blood donors and sickle cell disease patients

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

DNA repair gene polymorphism is associated with the genetic basis of atherosclerotic coronary artery disease

Background: Atherosclerotic coronary artery disease (CAD) is a multifactorial process that appears to be caused by the interaction of environmental risk factors with multiple predisposing genes. It is nowadays accepted that increased levels of DNA damage induced by xenobiotics play an important role in the early phases of atherogenesis. Therefore, in this study, we focus on determining whether genetic variations in xenobiotic-metabolizing [glutathione-S-transferase theta 1 (GSTT1), glutathione-S-transferase mu 1 (GSTM1), cytochrome P450 IIEI (CYP2E1)] and DNA repair [X-ray cross-complementing group 1 (XRCC1)] genes might be associated with increased risk for CAD. Methods: A case-control study was conducted with 400 individuals who underwent subjected to coronary angiography. A total of 299 were patients diagnosed with effective coronary atherosclerosis (case group; >20% obstructive lesion), and 101 (control group) were individuals diagnosed as negative for CAD (<20% obstructive lesions). The polymorphism identifications for GSTM1 and GSTT1, and for CYP2E1 and XRCC1 genes were performed by polymerase chain reaction (PCR) amplification and by PCR-RFLP, respectively. Results and conclusions: The XRCC1 homozygous wild-type genotype Arg/Arg for codon 399 was statistically less pronounced in the case subjects (21.4%) than in controls (38.5%); individuals with the variant XRCC1 genotype had a 2.3-fold increased risk for coronary atherosclerosis than individuals with the wild-type genotype (OR=2.3, 95% CI=1.13-4.69). Conversely, no association between GSTM1, GSTT1, and CYP2E1gene polymorphisms and coronary atherosclerosis was detected. The results provide evidence of the role of DNA damage and repair in cardiovascular disease. © 2011 Elsevier Inc. All rights reserved.

Mannose-binding lectin gene polymorphism and risk factors for cardiovascular disease in postmenopausal women

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PSEN1 and PSEN2 Gene Expression in Alzheimer's Disease Brain: A New Approach

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Gene expression profiles displayed by peripheral blood mononuclear cells from patients with type 2 diabetes mellitus focusing on biological processes implicated on the pathogenesis of the disease

Patients with type 2 diabetes mellitus (T2DM) exhibit insulin resistance associated with obesity and inflammatory response, besides an increased level of oxidative DNA damage as a consequence of the hyperglycemic condition and the generation of reactive oxygen species (ROS). In order to provide information on the mechanisms involved in the pathophysiology of T2DM, we analyzed the transcriptional expression patterns exhibited by peripheral blood mononuclear cells (PBMCs) from patients with T2DM compared to non-diabetic subjects, by investigating several biological processes: inflammatory and immune responses, responses to oxidative stress and hypoxia, fatty acid processing, and DNA repair. PBMCs were obtained from 20 T2DM patients and eight non-diabetic subjects. Total RNA was hybridized to Agilent whole human genome 4x44K one-color oligo-microarray. Microarray data were analyzed using the GeneSpring GX 11.0 software (Agilent). We used BRB-ArrayTools software (gene set analysis - GSA) to investigate significant gene sets and the Genomica tool to study a possible influence of clinical features on gene expression profiles. We showed that PBMCs from T2DM patients presented significant changes in gene expression, exhibiting 1320 differentially expressed genes compared to the control group. A great number of genes were involved in biological processes implicated in the pathogenesis of T2DM. Among the genes with high fold-change values, the up-regulated ones were associated with fatty acid metabolism and protection against lipid-induced oxidative stress, while the down-regulated ones were implicated in the suppression of pro-inflammatory cytokines production and DNA repair. Moreover, we identified two significant signaling pathways: adipocytokine, related to insulin resistance; and ceramide, related to oxidative stress and induction of apoptosis. In addition, expression profiles were not influenced by patient features, such as age, gender, obesity, pre/post-menopause age, neuropathy, glycemia, and HbA(1c) percentage. Hence, by studying expression profiles of PBMCs, we provided quantitative and qualitative differences and similarities between T2DM patients and non-diabetic individuals, contributing with new perspectives for a better understanding of the disease. (C) 2012 Elsevier B.V. All rights reserved.

Sequence and Copy Number Analyses of HEXB Gene in Patients Affected by Sandhoff Disease: Functional Characterization of 9 Novel Sequence Variants

Sandhoff disease (SD) is a lysosomal disorder caused by mutations in the HEXB gene. To date, 43 mutations of HEXB have been described, including 3 large deletions. Here, we have characterized 14 unrelated SD patients and developed a Multiplex Ligation-dependent Probe Amplification (MLPA) assay to investigate the presence of large HEXB deletions. Overall, we identified 16 alleles, 9 of which were novel, including 4 sequence variation leading to aminoacid changes [c.626C>T (p.T209I), c.634C>A (p.H212N), c.926G>T (p.C309F), c.1451G>A (p.G484E)] 3 intronic mutations (c.1082+5G>A, c.1242+1G>A, c.1169+5G>A), 1 nonsense mutation c.146C>A (p.S49X) and 1 small in-frame deletion c.1260_1265delAGTTGA (p.V421_E422del). Using the new MLPA assay, 2 previously described deletions were identified. In vitro expression studies showed that proteins bearing aminoacid changes p.T209I and p.G484E presented a very low or absent activity, while proteins bearing the p.H212N and p.C309F changes retained a significant residual activity. The detrimental effect of the 3 novel intronic mutations on the HEXB mRNA processing was demonstrated using a minigene assay. Unprecedentedly, minigene studies revealed the presence of a novel alternative spliced HEXB mRNA variant also present in normal cells. In conclusion, we provided new insights into the molecular basis of SD and validated an MLPA assay for detecting large HEXB deletions.

New mutations in the GLA gene in Brazilian families with Fabry disease

Fabry disease (FD) is an X-linked inborn error of glycosphingolipid catabolism that results from mutations in the alpha-galactosidase A (GLA) gene. Evaluating the enzymatic activity in male individuals usually performs the diagnosis of the disease, but in female carriers the diagnosis based only on enzyme assays is often inconclusive. In this work, we analyzed 568 individuals from 102 families with suspect of FD. Overall, 51 families presented 38 alterations in the GLA gene, among which 19 were not previously reported in literature. The alterations included 17 missense mutations, 7 nonsense mutations, 7 deletions, 6 insertions and 1 in the splice site. Six alterations (R112C, R118C, R220X, R227X, R342Q and R356W) occurred at CpG dinucleotides. Five mutations not previously described in the literature (A156D, K237X, A292V, I317S, c.1177_1178insG) were correlated with low GLA enzyme activity and with prediction of molecular damages. From the 13 deletions and insertions, 7 occurred in exons 6 or 7 (54%) and 11 led to the formation of a stop codon. The present study highlights the detection of new genomic alterations in the GLA gene in the Brazilian population, facilitating the selection of patients for recombinant enzyme-replacement trials and offering the possibility to perform prenatal diagnosis. Journal of Human Genetics (2012) 57, 347-351; doi:10.1038/jhg.2012.32; published online 3 May 2012

Wilson’s disease in Southern Brazil: genotype-phenotype correlation and description of two novel mutations in ATP7B gene

OBJECTIVE: Wilson's disease (WD) is an inborn error of metabolism caused by abnormalities of the copper-transporting protein encoding gene ATP7B. In this study, we examined ATP7B for mutations in a group of patients living in southern Brazil. METHODS: 36 WD subjects were studied and classified according to their clinical and epidemiological data. In 23 subjects the ATP7B gene was analyzed. RESULTS: Fourteen distinct mutations were detected in at least one of the alleles. The c.3207C>A substitution at exon 14 was the most common mutation (allelic frequency=37.1%) followed by the c.3402delC at exon 15 (allelic frequency=11.4%). The mutations c.2018-2030del13 at exon 7 and c.4093InsT at exon 20 are being reported for the first time. CONCLUSION: The c.3207C>A substitution at exon 14, was the most common mutation, with an allelic frequency of 37.1%. This mutation is the most common mutation described in Europe.

Gene therapy for a novel mouse model of Canavan disease

Canavan disease (CD) is a rare leukodystrophy caused by loss-of-function mutations in the gene encoding aspartoacylase (ASPA), an oligodendrocyte-enriched enzyme. It is characterised by the accumulation of the ASPA substrate N-acetylaspartate (NAA) in brain, blood and urine, leading to a spongiform vacuolisation of the brain, severe motoric and cognitive impairments and premature death. To date, no therapy is available due to the lack of a gene-transfer system allowing transgene expression in oligodendrocytes (OLs) and the restoration of the missing enzyme. Hence, the aim of this study was to establish a novel gene-transfer system and its preclinical evaluation in a CD animal model.rnIn the first part of this thesis, a novel ASPA mouse mutant was generated. A βgeo cassette (including the genes encoding β-galactosidase and neomycin) flanked by frt sites was inserted into intron 1 of the intact aspa gene. Additionally, exon 2 was flanked by loxP sites for optional conditional deletion of the targeted locus. The resulting ASPA-deficient aspalacZ/lacZ-mouse was found to be an accurate model of CD and an important tool to identify novel aspects of its complex pathology. Homozygous mutants showed a CD-like histopathology, neurological impairment, behavioural deficits as well as a reduced body weight. Additionally, MRI data revealed changes in brain metabolite composition. rnRecombinant adeno-associated viral (rAAV) vectors have become a versatile tool for gene transfer to the central nervous system because they are efficient, non-toxic and replication-deficient. Based on the natural neurotropism of AAV vectors, AAV-based gene delivery has entered the clinics for the treatment of neurodegenerative diseases. However, the lack of AAV vectors with oligodendroglial tropism has precluded gene therapy for leukodystrophies. In the second part of this work, it was shown that the transduction profile of established AAV serotypes can be targeted towards OLs in a transcriptional approach, using the oligodendrocyte-specific myelin basic protein (MBP) promoter to drive transgene expression in OLs.rnIn the last part of this work, the therapeutic efficacy of AAV-mediated aspa gene transfer to OLs of juvenile aspalacZ/lacZ mice was evaluated. AAV-aspa injections into multiple sites of the brain parenchyma resulted in transduction of OLs in the grey and white matter throughout the brain. Histological abnormalities in the brain of ASPA-deficient mice were ameliorated and accompanied by a reduction of NAA levels. Furthermore, the treatment resulted in normalisation of body weight, motor function and nest-building behaviour. These data provide a proof-of-concept for a successful gene therapy of Canavan disease. This might pave the way towards translation into clinical application and serve as the basis for the genetic treatment of other leukodystrophies.

VHL-gene deletion in single renal tubular epithelial cells and renal tubular cysts: further evidence for a cyst-dependent progression pathway of clear cell renal carcinoma in von Hippel-Lindau disease

Inheritance of a mutant allele of the von Hippel-Lindau tumor suppressor gene predisposes affected individuals to develop renal cysts and clear cell renal cell carcinoma. Von Hippel-Lindau gene inactivation in single renal tubular cells has indirectly been showed by immunohistochemical staining for the hypoxia-inducible factor alpha target gene product carbonic anhydrase IX. In this study we were able to show von Hippel-Lindau gene deletion in carbonic anhydrase IX positive nonneoplastic renal tubular cells, in epithelial cells lining renal cysts and in a clear cell renal cell carcinoma of a von Hippel-Lindau patient. This was carried out by means of laser confocal microscopy and immunohistochemistry in combination with fluorescence in situ hybridization. Carbonic anhydrase IX negative normal renal tubular cells carried no von Hippel-Lindau gene deletion. Furthermore, recent studies have indicated that the von Hippel-Lindau gene product is necessary for the maintenance of primary cilia stability in renal epithelial cells and that disruption of the cilia structure by von Hippel-Lindau gene inactivation induces renal cyst formation. In our study, we show a significant shortening of primary cilia in epithelial cells lining renal cysts, whereas, single tubular cells with a von Hippel-Lindau gene deletion display to a far lesser extent signs of cilia shortening. Our in vivo results support a model in which renal cysts represent precursor lesions for clear cell renal cell carcinoma and arise from single renal tubular epithelial cells owing to von Hippel-Lindau gene deletion.

Characterization of the porcine transferrin gene (TF) and its association with disease severity following an experimental Actinobacillus pleuropneumoniae infection

Transferrin (TF)-mediated provision of iron is essential for a productive infection by many bacterial pathogens, and iron-depletion of TF is a first line defence against bacterial infections. Therefore, the transferrin (TF) gene can be considered a candidate gene for disease resistance. We obtained the complete DNA sequence of the porcine TF gene, which spans 40 kb and contains 17 exons. We identified polymorphisms on a panel of 10 different pig breeds. Comparative intra- and interbreed sequence analysis revealed 62 polymorphisms in the TF gene including one microsatellite. Ten polymorphisms were located in the coding sequence of the TF gene. Four SNPs (c.902A>T, c.980G>A, c.1417A>G, c.1810A>C) were predicted to cause amino acid exchanges (p.Lys301Ile, p.Arg327Lys, p.Lys473Glu, p.Asn604His). We performed association analyses using six selected TF markers and 116 pigs experimentally infected with Actinobacillus pleuropneumoniae serotype 7. The analysis showed breed-specific TF allele frequencies. In German Landrace, we found evidence for a possible association of the severity of A. pleuropneumoniae infection with TF genotypes.

Crohn's disease-associated polymorphism within the PTPN2 gene affects muramyl-dipeptide-induced cytokine secretion and autophagy

The single nucleotide polymorphism (SNP) rs2542151 within the gene locus region encoding protein tyrosine phosphatase non-receptor type 2 (PTPN2) has been associated with Crohn's disease (CD), ulcerative colitis (UC), type-I diabetes, and rheumatoid arthritis. We have previously shown that PTPN2 regulates mitogen-activated protein kinase (MAPK) signaling and cytokine secretion in human THP-1 monocytes and intestinal epithelial cells (IEC). Here, we studied whether intronic PTPN2 SNP rs1893217 regulates immune responses to the nucleotide-oligomerization domain 2 (NOD2) ligand, muramyl-dipeptide (MDP).