RESUMEN
BACKGROUND: The purpose of our study was to investigate the potential contribution of germline mutations in NOTCH1, GATA5 and TGFBR1 and TGFBR2 genes in a cohort of Italian patients with familial Bicuspid Aortic Valve (BAV). METHODS: All the coding exons including adjacent intronic as well as 5' and 3' untranslated (UTR) sequences of NOTCH1, GATA5, TGFBR1 and TGFBR2 genes were screened by direct gene sequencing in 11 index patients (8 males; age = 42 ± 19 years) with familial BAV defined as two or more affected members. RESULTS: Two novel mutations, a missense and a nonsense mutation (Exon 5, p.P284L; Exon 26, p.Y1619X), were found in the NOTCH1 gene in two unrelated families. The mutations segregated with the disease in these families, and they were not found on 200 unrelated chromosomes from ethnically matched controls. No pathogenetic mutation was identified in GATA5, TGFBR1 and TGFBR2 genes. CONCLUSIONS: Two novel NOTCH1 mutations were identified in two Italian families with BAV, highlighting the role of a NOTCH1 signaling pathway in BAV and its aortic complications. These findings are of relevance for genetic counseling and clinical care of families presenting with BAV. Future studies are needed in order to unravel the still largely unknown genetics of BAV.
Asunto(s)
Factor de Transcripción GATA5/genética , Mutación de Línea Germinal , Enfermedades de las Válvulas Cardíacas/genética , Proteínas Serina-Treonina Quinasas/genética , Receptor Notch1/genética , Receptores de Factores de Crecimiento Transformadores beta/genética , Regiones no Traducidas 3' , Regiones no Traducidas 5' , Adolescente , Adulto , Anciano , Válvula Aórtica/anomalías , Enfermedad de la Válvula Aórtica Bicúspide , Estudios de Casos y Controles , Cromosomas Humanos/genética , Codón sin Sentido/genética , Análisis Mutacional de ADN/métodos , Exones , Femenino , Variación Genética , Genética de Población/métodos , Enfermedades de las Válvulas Cardíacas/etnología , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Mutación Missense , Linaje , Receptor Tipo I de Factor de Crecimiento Transformador beta , Receptor Tipo II de Factor de Crecimiento Transformador beta , Transducción de Señal , Adulto JovenRESUMEN
BACKGROUND: Ascending thoracic aortic aneurysm (ATAA) is a major cause of morbidity and mortality worldwide. The pathogenesis of medial degeneration of the aorta remains undefined. High-throughput secretome analysis by mass spectrometry may be useful to elucidate the molecular mechanisms involved in aneurysm formation as well as to identify biomarkers for early diagnosis or targets of therapy. The purpose of the present study was to analyze the secreted/released proteins from ATAA specimens of both tricuspid aortic valve (TAV) and bicuspid aortic valve (BAV) patients. METHODS: Aortic specimens were collected from patients undergoing elective surgery and requiring graft replacement of the ascending aorta. Each sample of the ascending aortic aneurysm, 4 BAV (3 males; aged 53.5±11.4 years) and 4 TAV (1 male; 78±7.5 years), was incubated for 24h in serum-free medium. Released proteins were digested with trypsin. Peptide mixtures were fractioned by nano-high performance liquid chromatography and analyzed by mass spectrometry. Following identification of differentially expressed proteins, quantitative real time polymerase chain reaction (qRT-PCR) analysis was performed. RESULTS: The comparison between the proteins released from BAV and TAV aneurysmatic tissues showed significantly diverging expression fingerprints in the two groups of patients. Bioinformatics analysis revealed 38 differentially released proteins; in particular 7 proteins were down-regulated while 31 were up-regulated in BAV with respect to TAV. Most of the proteins that were up-released in BAV were related to the activation of transforming growth factor (TGF)-ß signaling. Latent TGF-ß binding protein 4 (LTBP4) exhibited one of the highest significant under-expressions (10-fold change) in BAV secretomes with respect to TAV. qRT-PCR analysis validated this significant difference at LTBP4 gene level (BAV: 1.03±0.9 vs TAV: 3.6±3.2; p<0.05). CONCLUSION: Hypothesis-free secretome profiling clearly showed diverging expression fingerprints in the ATAA of TAV and BAV patients, confirming the crucial role of TGF-ß signaling in modulating ATAA development in bicuspid patients.
Asunto(s)
Aneurisma de la Aorta Torácica/metabolismo , Válvula Aórtica/anomalías , Enfermedades de las Válvulas Cardíacas/metabolismo , Factor de Crecimiento Transformador beta/metabolismo , Válvula Tricúspide/metabolismo , Anciano , Aorta/patología , Aneurisma de la Aorta/patología , Válvula Aórtica/metabolismo , Enfermedad de la Válvula Aórtica Bicúspide , Femenino , Humanos , Proteínas de Unión a TGF-beta Latente/metabolismo , Masculino , Persona de Mediana Edad , Transducción de SeñalRESUMEN
We report the clinical presentation and genetic screening of 2 patients with thoracic aortic aneurysms. A novel TGFBR2 mutation in the 5'untranslated region (c.-59C>T) was identified in a 31-year-old man with a Stanford type A aortic dissection. Bioinformatics tools showed that c.-59C>T variant was predicted to affect exonic splicing enhancer, as validated by quantitative real-time RT-PCR, revealing a sixfold increase of TGFBR2 mRNA in aneurysmal aortic tissue collected during surgery. A previously described missense mutation, p.E239K, in the SMAD3 gene was identified in a 60-year-old man who presented with diffuse vasculopathy. These findings suggest that the features of aneurysmal disease extending beyond the ascending aorta may help to target SMAD3 genetic screening and that alterations in the core splicing machinery can contribute to aneurysmal disease.