Biomedical subjects

Luca Scapoli

Publications and source records attributed to Luca Scapoli.

23 records · Page 2Linked to original sources

PubMed2002

Basic fibroblast growth factor: effects on matrix remodeling, receptor expression, and transduction pathway in human periosteal fibroblasts with FGFR2 gene mutation.

The Crouzon syndrome, which is associated with fibroblast growth factor receptor (FGFR2) mutations, is characterized by premature fusion of cranial sutures. We used an in vitro model of cultured periosteal fibroblasts from normal subjects and from Crouzon patients with FGFR2 mutation. We analyzed the matrix turnover rate and the effects of adding FGF2 by evaluating fibronectin synthesis and the activity of some proteolytic enzymes. To assess the role of some FGF signaling molecules involved in FGFR2 regulation, we studied Grb2 tyrosine phosphorylation and the phosphotyrosine proteins associated with Grb2. The iodinate FGF binding assay was performed to quantify FGFR expression. Compared with normal fibroblasts, fibronectin synthesis was decreased in Crouzon fibroblasts, and protease activities in cells and medium were enhanced, suggesting that excess fibronectin catabolism is present. Differences were more marked when FGF2 was added. Very few phosphoproteins were visible in anti-Grb2 immunoprecipitations from Crouzon fibroblasts, which showed a significant increase in the number of high-affinity and low-affinity FGF2 receptors. These results suggest that the abnormal genotype and the Crouzon cellular phenotype are related. To compensate the low levels of tyrosine phosphorylation, Crouzon cells might increase the numbers of FGFR2, thus increasing the cell surface binding sites for FGF2.

Adaptor Proteins, Signal Transducing↗

PubMed2002

Expression profiles of craniosynostosis-derived fibroblasts.

BACKGROUND: Craniosynostosis syndromes, a group of connective disorders characterized by abnormalities in vault osteogenesis and premature fusion of bone sutures, are associated with point mutations in FGF receptor family members. The cellular phenotype is characterized by abnormal extracellular matrix turnover. MATERIAL AND METHODS: We used primary cultures of periosteal fibroblasts derived from two different craniosynostosis syndromes, the Apert and Crouzon syndromes. The FGFR2 third immunoglobulin-like domain and its flanking linker regions were analyzed for mutation. DNA microarrays containing 19,200 cDNAs were used to study the gene expression profiles of Apert and Crouzon fibroblasts. The pathologic cells were compared to wild-type human periosteal fibroblasts. RESULTS: The P253R missense mutation and the G338R mutation were observed in Apert and Crouzon fibroblasts, respectively. The genetic profiles, as evaluated by DNA microarrays, yielded different clusters of expressed sequence tag (ESTs) expression within the experiment. Expression profiles from craniosynostosis-derived fibroblasts differ from those of wild-type fibroblasts (288 human ESTs, p< 0.01, pFDR = 0.12). Furthermore, two ESTs clusters discriminate the Crouzon from Apert fibroblasts. The differentially expressed genes cover a broad range of functional activities, including (1) bone differentiation, (2) cell-cycle regulation, (3) apoptotic stimulation, and (4) signaling transduction, cytoskeleton, and vesicular transport. CONCLUSIONS: The transcriptional program of craniosynostosis fibroblasts differs from that of wild-type fibroblasts. Expression profiles of Crouzon and Apert fibroblasts can also be distinguished by two EST expression clusters, thus hinting at a different genetic background.

Acrocephalosyndactylia↗

PubMed2002

Identification of differentially expressed genes in human salivary gland tumors by DNA microarrays.

Differentially expressed genes among different benign and malignant salivary gland tumors were identified by use of cDNA microarrays containing 19,000 human expressed sequence tags. Tumors were classified by using a subset of 486 genes. Benign Warthin's tumor and pleomorphic adenoma showed very distinctive gene expression patterns. One hundred and thirty-three genes differentiated the single malignant clear cell carcinoma from non-tumor salivary glands (P < 0.01), whereas only 16 genes separated it from the highly related benign pleomorphic adenoma (P < 0.01). Fifty-seven cDNAs were associated with mucoepidermoid carcinoma (P < 0.01). The identified genes might help to disclose the molecular mechanisms and processes underlying malignant salivary gland tumors.

DNA, Complementary↗

PubMed2001

Linkage disequilibrium between GABRB3 gene and nonsyndromic familial cleft lip with or without cleft palate.

The malformation of nonsyndromic cleft lip with or without cleft palate (CL/P) is a common congenital disease that affects approximately 1/1000 newborns in Caucasian populations. Genetic studies indicate that CL/P has the characteristics of a complex genetic trait. Linkage analysis and mouse-model knockout studies have suggested several candidate genes mapping in different chromosome regions for CL/P malformation. On these grounds, we have investigated, by linkage disequilibrium (LD) and parametric and nonparametric linkage analyses, five different candidate genes, including those for the beta3 subunit of the gamma-aminobutyric acid receptor (GABRB3), glutamic acid decarboxylase 1 (GAD1), retinoic acid receptor alpha (RARA), transforming growth factor beta3 (TGFB3), and msh ( Drosophila) homeobox homolog 1 (MSX1). Interestingly, a significant LD between GABRB3 and CL/P was obtained ( P-value=0.008 in the allele-wise analysis for multiallelic markers), suggesting that the GABRB3 gene is involved in this congenital disease. This new finding in humans is in agreement with previously reported data obtained with the murine model. Indeed, mouse studies indicate a role for gamma-aminobutyric acid (GABA) and its receptor in normal palate development. Exclusion of the GAD1 gene, which encodes the GABA-producing enzyme, in CL/P pathogenesis was obtained in our study. Moreover, we were unable to confirm the involvement of the MSX1 gene in nonsyndromic CL/P. Modest evidence of LD between marker alleles and CL/P was found at the RARA and TGFB3 loci suggesting a minor role for these genes in our family set of nonsyndromic CL/P.

Cleft Lip↗

PubMedDate not supplied

The effect of polyamines and dialysate fluid on extracellular matrix synthesis in VERO cell cultures.

BACKGROUND: Polyamines are involved in normal and pathological cell proliferation and differentiation. Like acid radicals, they play an important role in remodelling the extracellular matrix and are considered "uremic toxins". Proteins and glycosaminoglycans are essential components of the extracellular matrix, and contribute to normal mature organ functions. The aim of this study was to analyse the effects of free polyamines, dialysate fluid components and dialysis fluid on protein and extracellular glycosaminoglycan synthesis in VERO cell cultures. METHODS: The dialysate fluid components were separated with a Sephadex G15 column and the cultures were analysed after incorporation of 3H-leucine and 3H-glucosamine. Cultures were run at pH 7.0 and pH 7.4. The glycosaminoglycan classes were separated with a DEAE column, and polyamines were determined by high-performance liquid chromatography. Proteins and single glycosaminoglycan classes were quantified by a scintillator. DNA gel electrophoresis was done to detect chromatin fragmentation. RESULTS: Dialysate contained putrescine, spermidine and spermine, chromatography showing four peaks; only peaks I and II indicated polyamines at respectively Da 5000 and 1500. Polyamines are therefore linked to different carriers. There was an increase of protein and glycosaminoglycan synthesis with dialysis fluid and polyamines, but inhibition with peak II or dialysate. DNA gel electrophoresis showed no chromatin fragmentation. Findings at pH 7.0 and 7.4 were similar. CONCLUSIONS: It would appear that in uremic patients polyamines are conjugated to protein carriers of different molecular weights with different biological actions. As polyamines and dialysis fluid affect changes in extracellular matrix, they could be related to physiological organ functions. However, these in vitro data must be considered with the appropriate limitations when we try to extrapolate them to the in vivo situation.

Animals↗