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Ghiggeri G.M.,Gaslini Children Hospital | Gigante M.,University of Foggia | Di Donato A.,Gaslini Children Hospital | Di Donato A.,Laboratorio Of Nefrologia
International Journal of Nephrology | Year: 2013

The kidney glomerular podocytes are the cellular target of many chronic nephropathies both determined and acquired genetically. Mutations that affected the expression and/or the function of nephrin, a key component of the slit-diaphragm, are often causes of these pathologies. Recent findings showed that murine podocytes could undergo epithelial-mesenchymal transformation (EMT), suggesting new hypotheses about the pathogenesis of glomerular fibrosis. Here, we show that also human podocytes can undergo EMT, but more importantly nephrin ablation itself can trigger this phenotypic transformation. In fact, a model of human podocyte with engineered nephrin deficiency constitutionally expressed high levels of α -SMA, vimentin, fibronectin, and other hallmarks of EMT. Since it is known that cell contact abrogation is one of the triggers of EMT, we reasoned that nephrin loss could account for such cell junction disruption and cause the EMT. Therefore, we demonstrated that also normal podocytes could spontaneously undergo EMT if grown in Ca2+-free medium, which is known to impair cell contacts. The analysis of the main intracellular signal transduction pathways evidenced some major anomalies consequent with the nephrin abrogation. The most intriguing was the activation of β -catenin pathway, which plays a critical role in podocyte ontogenesis as well as in the nephrin expression and EMT regulation. Also other important signaling proteins, like NF- B, p53, and retinoblastoma protein (RB), showed important activity modifications. Interestingly, most of the above indicated signaling pathway alterations were again reproducible by cell junction rupture, induced by Ca 2+ deprivation. Finally, immunofluorescence analysis on kidney sections of patients with NS of Finnish type confirmed the constitutive expression of α -SMA. © 2013 Gian Marco Ghiggeri et al.

Baban A.,Bambino Gesu Pediatric Hospital | Torre M.,Gaslini Children Hospital | Costanzo S.,Gaslini Children Hospital | Gimelli S.,University of Geneva | And 10 more authors.
American Journal of Medical Genetics, Part A | Year: 2012

Poland anomaly (PA) is a pectoral muscle hypoplasia/aplasia variably associated with ipsilateral thoracic (TA) and/or upper limb anomalies (ULA). PA is usually sporadic and sometimes familial, making recurrence risk an issue in genetic counseling. Multidisciplinary evaluation of 240 PA patients was carried out, including physical examination of patients and their parents in 190 PA (subjects of the study). Familial conditions were classified into three groups. Group1: true familial PA (F-PA): pectoral muscle defects with familial recurrence: 8(4.2%). Group2: familial Poland-like anomaly families (F-PLA): PA index case and ≥1 relative(s) showing normal pectoral muscles but ULA and/or TA common in PA: 16(8.4%). Group3: sporadic PA (S-PA): 166(87.4%). F-PA indicated a stronger male (87.5%) and left side (62.5%) prevalence, but fewer ULA (37.5%) compared to the other two groups. Maternal transmission (6/8) was more common in F-PA. Statistical significance was not reached due to the small number of F-PA and F-PLA. Karyotyping and array-comparative genomic hybridization were performed in 13 families. Three maternally inherited copy number variants were identified in three patients: 1p31.1 deletion, Xp11.22 duplication, and 16q23.1 duplication. Interestingly, the proband's mother carrying the 16q23.1 duplication displayed moderate breast and areola asymmetry, but normal pectoral muscles on ultrasound. Though there is no recent review discussing recurrence of PA, we reviewed 31 published PA families. On the basis of our study and previous reports, familial PA is not uncommon. Nonetheless, no information can be derived either regarding a molecular basis or clinical tools with which to identify cases with recurrence risk. © 2011 Wiley Periodicals, Inc.

Torre M.,Gaslini Children Hospital | Baban A.,Laboratory of Molecular Genetics | Buluggiu A.,Gaslini Children Hospital | Costanzo S.,Gaslini Children Hospital | And 7 more authors.
Journal of Thoracic and Cardiovascular Surgery | Year: 2010

Objective: Poland syndrome is a rare congenital anomaly characterized by complete or partial agenesis of the pectoralis major muscle variably associated with other thoracic malformations, upper limb malformations, or both. More than 20 patients with dextrocardia and left-sided Poland syndrome have been previously described. The association between these 2 rare anomalies suggests a causal relationship, but the etiopathogenetic mechanism has not been clarified yet. We studied the clinical correlation between these 2 anomalies, and we tried to elucidate whether dextrocardia or Poland syndrome comes first. Methods: This is a multicentric multidisciplinary study conducted over the last 5 years. We identified 122 patients with Poland syndrome, and we investigated heart position through different imaging techniques. Logistic regression statistical analyses were carried out. Results: We observed dextrocardia in 14 (11.5%) patients, which was never associated with situs inversus. All of them presented with left-sided Poland syndrome and partial agenesis of 2 or more ribs. Conversely, all patients with Poland syndrome with partial agenesis of 2 or more ribs presented with dextrocardia, whereas dextrocardia was never associated with partial agenesis of a single rib. Three patients with dextrocardia presented with simple congenital heart defects. Conclusions: These findings suggest that mechanical factors during embryonic life could explain the strong association between left-sided Poland syndrome and dextrocardia. According to this hypothesis, partial agenesis of 2 or more ribs is needed to displace the heart toward the right side. The peculiar features of dextrocardia when associated with Poland syndrome (neither associated with situs inversus nor complex intracardiac anomalies) support our hypothesis. © 2010 The American Association for Thoracic Surgery.

Baban A.,Bambino Gesu Children Hospital | Marini M.,Laboratory of Molecular Genetics | Trocchio G.,Gaslini Children Hospital | Santilli A.,Bambino Gesu Children Hospital | And 9 more authors.
American Journal of Medical Genetics, Part A | Year: 2014

Tetralogy of Fallot (TOF) (OMIM #187500) is the most frequent conotruncal congenital heart defect (CHD) with a range of intra- and extracardiac phenotypes. TBX5 is a transcription factor with well-defined roles in heart and forelimb development, and mutations in TBX5 are associated with Holt-Oram syndrome (HOS) (OMIM#142900). Here we report on the screening of 94 TOF patients for mutations in TBX5, NKX2.5 and GATA4 genes. We identified two heterozygous mutations in TBX5. One mutation was detected in a Moroccan patient with TOF, a large ostium secundum atrial septal defect and complete atrioventricular block, and features of HOS including bilateral triphalangeal thumbs and fifth finger clinodactyly. This patient carried a previously described de novo, stop codon mutation (p.R279X) located in exon 8 causing a premature truncated protein. In a second patient from Italy with TOF, ostium secundum atrial septal defect and progressive arrhythmic changes on ECG, we identified a maternally inherited novel mutation in exon 9, which caused a substitution of a serine with a leucine at amino acid position 372 (p.S372L, c.1115C>T). The mother's clinical evaluation demonstrated frequent ventricular extrasystoles and an atrial septal aneurysm. Physical examination and radiographs of the hands showed no apparent skeletal defects in either child or mother. Molecular evaluation of the p.S372L mutation demonstrated a gain-of-function phenotype. We also review the literature on the co-occurrence of TOF and HOS, highlighting its relevance. This is the first systematic screening for TBX5 mutations in TOF patients which detected mutations in two of 94 (2.1%) patients. © 2014 Wiley Periodicals, Inc.

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