RESUMO
Pterygium is one of the most frequent pathologies in ophthalmology, and is a benign, fibrovascular lesion originating from the bulbar conjunctiva. It is composed of an epithelium and highly vascular, subepithelial, loose connective tissue. The etiology of pterygium is not clearly understood; the most widely recognized originating factor is ultraviolet radiation. It has been proposed that pterygium and neoplasia have common features, raising the possibility that pterygium is a neoplastic-like growth disorder. In this study, proteomic analysis was performed to show that peroxiredoxin 2 is overexpressed in pterygia compared to healthy conjunctivas. Twelve pterygium specimens were obtained together with healthy conjunctival tissue from the same eyes. Total proteins of pterygia and healthy conjunctivas were analyzed in SDS-PAGE. This analysis showed protein bands expressed exclusively in pterygium samples at the range of 20-25 kDa. After this, 2D electrophoresis was performed for the separation of total proteins; differential spots expressed in pterygium were excised and sequenced. Mass spectrometry (MS) data were searched in the NCBInr and EST databases using the MASCOT program. The spot was identified as peroxiredoxin 2. Real-time PCR, western blot and immunohistochemistry showed that peroxiredoxin 2 was increased in pterygium compared to healthy conjunctiva. Although, these results suggest that overexpression of peroxiredoxin 2 in pterygium could protect the cell against oxidative stress-induced apoptosis, further studies are required to establish the functional role of peroxiredoxin 2 in pterygium to determine its role in peroxidation and apoptosis in this pathology.
Assuntos
Proteínas do Olho/metabolismo , Peroxirredoxinas/metabolismo , Pterígio/enzimologia , Adulto , Sequência de Aminoácidos , Western Blotting , Túnica Conjuntiva/enzimologia , Eletroforese em Gel Bidimensional , Eletroforese em Gel de Poliacrilamida , Proteínas do Olho/química , Proteínas do Olho/genética , Feminino , Humanos , Imuno-Histoquímica , Focalização Isoelétrica , Masculino , Espectrometria de Massas , Dados de Sequência Molecular , Peso Molecular , Oxirredução , Peroxirredoxinas/química , Peroxirredoxinas/genética , Proteômica , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
BACKGROUND: Oculopharyngeal muscular dystrophy (OPMD) is a late onset hereditary myopathy of autosomal dominant transmission characterised by ptosis, dysphagia and limb weakness. The disease is caused by short heterozygous expansions of a (GCN)(10) triplet located in the first exon of the PABPN1 gene at chromosome 14q11.1. Most affected individuals from North America and Europe carry a mutant (GCN)(13) allele. Although evidence for a founder mutation effect has been shown in several populations with OPMD, analysis of large groups of patients from different ethnic backgrounds will help to identify the relative contribution of each allele to the disease and a possible genotype-phenotype correlation. METHODS: 22 unrelated patients with OPMD from Mexico, a previously uncharacterised population, were clinically and molecularly analysed. Detailed ophthalmological and clinical examinations were performed in each proband and molecular analysis of the PABPN1 gene was carried out by PCR amplification and allele-specific cloning/sequencing. Two single nucleotide polymorphisms (SNPs) linked to PABPN1 were determined in each individual and in a number of affected first-degree relatives. RESULTS: 15 subjects (68%) carried a mutant (GCN)(15) or (GCG)(11)(GCA)(3)(GCG) PABPN1 allele; the remaining 7 (32%) exhibited an abnormal (GCN)(13) or (GCG)(9)(GCA)(3)(GCG) allele. Analysis of two SNPs linked to PABPN1 strongly suggests that both expanded alleles originate from two independent founder effects. In addition, in this particular population the (GCN)(15) allele was associated with an earlier onset of the disease (mean 46.5 years) compared with the (GCN)(13) allele (mean 54.7 years). CONCLUSION: The results of this study suggest that OPMD in the Mexican population is mostly due to (GCG)(11) or (GCG)(9) PABPN1 expanded alleles arising from two independent founder effect mutations. These findings add to the definition of the genetic features of the disease and to the establishment of a probable genotype-phenotype correlation.
Assuntos
Efeito Fundador , Distrofia Muscular Oculofaríngea/genética , Proteína I de Ligação a Poli(A)/genética , Adulto , Idoso , Alelos , Sequência de Bases , Feminino , Humanos , Masculino , México , Pessoa de Meia-Idade , Dados de Sequência Molecular , Polimorfismo de Nucleotídeo Único , Repetições de TrinucleotídeosRESUMO
OBJECTIVE: To determine the adenovirus serotype in Mexican patients with folicular conjunctivitis and keratoconjunctivitis. METHODS: Adenovirus-specific PCR was used to analyze sample scrapings from the inferior fornix of patients with follicular conjunctivitis and clinical suspicion of adenovirus from January 2005 to December 2006. Identification of the serotype was made by automated sequencing. The nucleotide sequences obtained were compared with the reported sequences in GenBank. Descriptive statistical analyses were performed on the results. RESULTS: Of the 77 samples with clinical data of follicular conjunctivitis that were analyzed, 43 (56%) presented adenovirus. The sequencing of each positive sample allowed the identification of Ad1, Ad2, Ad3 and Ad8; the sequences of the serotype were identical those reported in GenBank with accession numbers: AF 534906 and AY 224420 for a sequence of the gene coding for the filament of Ad1 and Ad2 respectively, and AY 854180 and DQ 149614 for a sequence of the gene that codes for the Hexon protein of Ad3 and Ad8 respectively. From the statistical analysis it was possible to determine that a preferential seasonality of the serotype does not exist. CONCLUSION: In this work the Ad1, Ad2 and Ad3 serotypes were identified in patients with clinical diagnosis of follicular conjunctivitis in 2005. Ad2 was the predominant serotype. Ad8 was also detected in an outbreak of epidemic keratoconjunctivitis. From an epidemiological point of view, no serotype found seems to have a preferred seasonality.