Subnuclear re-localization of SOX10 and p54NRB correlates with a unique neurological phenotype associated with SOX10 missense mutations.

SOX10 is a transcription factor with well-known functions in neural crest and oligodendrocyte development. Mutations in SOX10 were first associated with Waardenburg-Hirschsprung disease (WS4; deafness, pigmentation defects and intestinal aganglionosis). However, variable phenotypes that extend beyond the WS4 definition are now reported. The neurological phenotypes associated with some truncating mutations are suggested to be the result of escape from the nonsense-mediated mRNA decay pathway; but, to date, no mechanism has been suggested for missense mutations, of which approximately 20 have now been reported, with about half of the latter shown to be redistributed to nuclear bodies of undetermined nature and function in vitro. Here, we report that p54NRB, which plays a crucial role in the regulation of gene expression during many cellular processes including differentiation, interacts synergistically with SOX10 to regulate several target genes. Interestingly, this paraspeckle protein, as well as two other members of the Drosophila behavior human splicing (DBHS) protein family, co-localize with SOX10 mutants in nuclear bodies, suggesting the possible paraspeckle nature of these foci or re-localization of the DBHS members to other subnuclear compartments. Remarkably, the co-transfection of wild-type and mutant SOX10 constructs led to the sequestration of wild-type protein in mutant-induced foci. In contrast to mutants presenting with additional cytoplasmic re-localization, those exclusively found in the nucleus alter synergistic activity between SOX10 and p54NRB. We propose that such a dominant negative effect may contribute to or be at the origin of the unique progressive and severe neurological phenotype observed in affected patients.

Syndromic mental retardation with thrombocytopenia due to 21q22.11q22.12 deletion: Report of three patients.

During the last few years, an increasing number of microdeletion/microduplication syndromes have been delineated. This rapid evolution is mainly due to the availability of microarray technology as a routine diagnostic tool. Microdeletions of the 21q22.11q22.12 region encompassing the RUNX1 gene have been reported in nine patients presenting with syndromic thrombocytopenia and mental retardation. RUNX1 gene is responsible for an autosomal dominant platelet disorder with predisposition to acute myelogenous leukemia. We report on three novel patients with an overlapping "de novo" interstitial deletion involving the band 21q22 characterized by array-CGH. All our patients presented with severe developmental delay, dysmorphic features, behavioral problems, and thrombocytopenia. Comparing the clinical features of our patients with the overlapping ones already reported two potential phenotypes related to 21q22 microdeletion including RUNX1 were highlighted: thrombocytopenia with +/- mild dysmorphic features and syndromic thrombocytopenia with growth and developmental delay.

DNA immobilisation procedures for surface plasmon resonance imaging (SPRI) based microarray systems.

Two different surface chemistries have been studied for the development of surface plasmon resonance imaging (SPRI) based DNA microarray affinity sensors: (1) 11-mercaptoundecanoic acid-poly(ethylenimine) (MUA-PEI) and (2) dextran procedures. The MUA-PEI method consists of assembling a multilayer on the basis of electrostatic interactions formed with: 11-mercaptoundecanoic acid (MUA), poly(ethylenimine) (PEI) and extravidin layers. The dextran procedure involves assembling a multilayer formed with 11-mercaptoundecanol, dextran and streptavidin layers, which are linked by covalent bonds. The oligonucleotide probes are immobilised onto the sensor surface as spots forming a matrix 14x14, which is spotted by a robot, while the target sequences are free in solution. The system allows the interaction (hybridisation) monitoring, in real-time and in parallel, of unlabeled oligonucleotide solution targets to oligonucleotide probes immobilised on a 196 spots matrix. Using oligonucleotides as probes and targets, both functionalised surfaces have been evaluated in view of their application to the diagnosis of gene mutations involved in human diseases. In particular, we demonstrate the ability to detect, in parallel, several mutations causing human cystic fibrosis (CF), which lie within exon 10 of the human cystic fibrosis transmembrane conductance regulator (CFTR) gene. The immobilised probes were complementary to sequences corresponding the mutant or wild type alleles. Two deletions of three bases (DeltaF508 and DeltaI507) and four single nucleotide polymorphisms (M470V, Q493X, V520F and 1716 G>A) were investigated. In both functionalised surfaces, the system showed the capacity to discriminate normal and mutant sequences differing by a single base.

FGFR3 and TP53 gene mutations define two distinct pathways in urothelial cell carcinoma of the bladder.

FGFR3 and TP53 mutations are frequent in superficial papillary and invasive disease, respectively. We used denaturing high-performance liquid chromatography and sequencing to screen for FGFR3 and TP53 mutations in 81 newly diagnosed urothelial cell carcinomas. Tumors were classified as follows: 31 pTa, 1 carcinoma in situ, 30 pT1, and 19 pT2-T4. Tumor grades were as follows: 10 G1, 29 G2, and 42 G3. FGFR3 mutations were associated with low-stage (P < 0.0001), low-grade (P < 0.008) tumors, whereas TP53 mutations were associated with high-stage (P < 0.003), high-grade (P < 0.02) tumors. Mutations in these two genes were almost mutually exclusive. Our results suggest that FGFR3 and TP53 mutations define separate pathways at initial diagnosis of urothelial cell carcinoma.

Human urinary bladder transitional cell carcinomas acquire the functional Fas ligand during tumor progression.

The interaction between FasL on tumor cells and Fas on lymphocytes may represent a tumor immune escape mechanism. We explored FasL expression and function in human urinary bladder transitional cell carcinomas (TCCs). FasL expression was observed in situ in 45% of TCCs (n = 45) and was absent in normal urothelium (n = 20). A correlation existed between FasL expression and high tumor grade (0% in G1, 14% in G2, and 75% in G3; P < 0.0001) and stage (13% in superficial Ta-T1 versus 81% in invasive T2-T4; P < 0.0001). FasL function was shown by the ability of two FasL-positive primary culture TCC cell lines (established from two FasL-positive invasive TCCs) to induce Fas-mediated killing not only of conventional Fas-sensitive targets (such as Jurkat cells or phytohemagglutinin-lymphoblasts), but also of autologous T lymphocytes generated in a mixed lymphocyte tumor-cell culture. In addition, an association between FasL expression by TCC cells and activated caspase-8, -9, and -3 expression by interferon-gamma-producing CD8-positive tumor-infiltrating lymphocytes was observed in situ. Our results show a functional expression of TCC-expressed FasL that correlates with tumor progression. These results suggest that TCC-expressed FasL may induce apoptosis of anti-tumor T lymphocytes in vivo, providing new insights on the mechanisms involved in bladder TCC progression.

Aortic wall alterations after use of gelatin-resorcinol-formalin glue.

We report the case of a patient who underwent reoperation 8 years after aortic valve replacement because of aneurysmal dilatation of the aortic root. During the initial intervention, gelatin-resorcinol-formalin glue had been applied on the outside of the aortic root. Perioperative examination revealed a necrotic appearance of the right coronary sinus, with contained ruptures at two different sites. Histologic analysis showed major destruction of the aortic root media, leading to vascular wall thinning and rupture. The use of gelatin-resorcinolformalin glue may expose patients to major alterations of the aortic wall.