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Biomedical subjects

F Pezzetti

Publications and source records attributed to F Pezzetti.

At least 19 recordsLinked to original sources

Study of the PVRL1 gene in Italian nonsyndromic cleft lip patients with or without cleft palate.

Nonsyndromic cleft lip with or without cleft palate (CL/P) is a complex genetic trait and little is known about its aetiology. Recent investigations on rare clefting syndromes provided interesting clues about genes involved in face development. The PVRL1 gene encodes nectin1, a cell-to-cell adhesion molecule. Mutations in its sequence have been shown to cause the rare autosomal recessive syndrome CL/P-ectodermal dysplasia syndrome (CLPED1), while heterozygosity for the mutation W185X seemed to increase the risk of non syndromic CL/P in a population from northern Venezuela. In the present study, we screened 143 Italian CL/P patients for mutations in PVRL1. Three rare sequence variants in exon 3 that create amino-acid changes were detected in a total of 7 patients. Two of these mutations were not found in a panel of 292 unaffected controls, while the third was found in two controls. This study describes new mutations that may represent genetic risk factors for CL/P. Even though a study to look at the effects of the mutations on nectin1 function was not feasible, supporting evidence was reported, thus confirming the involvement of PVRL1 in the aetiology of non-syndromic CL/P malformation.

Cell Adhesion Molecules↗

Effects of Emdogain on osteoblast gene expression.

OBJECTIVE: Emdogain (EMD) is a protein extract purified from porcine enamel and has been introduced in clinical practice to obtain periodontal regeneration. EMD is composed mainly of amelogenins (90%), while the remaining 10% is composed of non-amelogenin enamel matrix proteins such as enamelins, tuftelin, amelin and ameloblastin. Enamel matrix proteins seem to be involved in root formation. EMD has been reported to promote proliferation, migration, adhesion and differentiation of cells associated with healing periodontal tissues in vivo. DESIGN: How this protein acts on osteoblasts is poorly understood. We therefore attempted to address this question by using a microarray technique to identify genes that are differently regulated in osteoblasts exposed to enamel matrix proteins. RESULTS: By using DNA microarrays containing 20,000 genes, we identified several upregulated and downregulated genes in the osteoblast-like cell line (MG-63) cultured with enamel matrix proteins (Emd). The differentially expressed genes cover a broad range of functional activities: (i) signaling transduction, (ii) transcription, (iii) translation, (iv) cell cycle regulation, proliferation and apoptosis, (v) immune system, (vi) vesicular transport and lysosome activity, and (vii) cytoskeleton, cell adhesion and extracellular matrix production. CONCLUSIONS: The data reported are the first genome-wide scan of the effect of enamel matrix proteins on osteoblast-like cells. These results can contribute to our understanding of the molecular mechanisms of bone regeneration and as a model for comparing other materials with similar clinical effects.

Animals↗

Maternal MTHFR variant forms increase the risk in offspring of isolated nonsyndromic cleft lip with or without cleft palate.

The pathogenesis of cleft lip with or without cleft palate (CL/P) is complex; its onset could be due to the interaction of various genetic and environmental factors. Recently MTHFR functional polymorphisms were found to increase the risk of this common malformation; however, this finding is still debated. We investigated 110 sporadic CL/P patients, their parents and 289 unrelated controls for c.665C>T (commonly known as 677C>T; p.Ala222Val) and c.1286A>C (known as 1298A>C; p.Glu429Ala) polymorphism in the MTHFR gene. Transmission disequilibrium test (TDT) showed no distortion in allele transmission. Nevertheless, association studies revealed significant differences in allele frequencies between mothers of CL/P patients and controls. This work supports the hypothesis that a lower MTHFR enzyme activity in pregnant women, mostly related to the c.665C>T variant form, is responsible for a higher risk of having CL/P affected offspring.

Adult Children↗

Titanium-cell interaction: analysis of gene expression profiling.

Titanium and its alloys are used worldwide in surgery. Dental implants, screws and plates, prostheses, and surgical instruments are made with titanium-based metals. The favorable characteristics that make this material desirable for implantation are (a) mechanical proprieties and (b) biocompatibility. The latter has been demonstrated by in vivo studies with animal models and clinical trials over a 40-year period. However, the exact effect of titanium on cells is still not well characterized. Expression profiling by DNA microarray is a new molecular technology that allows the analysis of gene expression in a cell system. Several genes whose expression was significantly up- or downregulated in an osteoblast-like cell line (MG-63) on titanium were identified with the use of DNA microarrays containing 19,200 genes. The differentially expressed genes are associated with a broad range of functional activities, including apoptosis, vesicular transport, and structural function. It was also possible to detect some genes whose function is unknown. The data reported are, to the author's knowledge, the first genetic portrait of titanium-cell interaction. They may help to provide a better understanding of the molecular mechanisms of titanium biocompatibility and serve as a model for studying the biocompatibility of other materials.

Animals↗

Genetic portrait of malignant granular cell odontogenic tumour.

Odontogenic tumours are rare neoplasms whose classification is sometime controversial. Among these entities, granular cell odontogenic tumour (GCOT) is extremely rare and usually has a benign clinical behaviour. While the histogenesis of GCOT remains to be clarified, we documented the existence of a malignant counterpart of this neoplasm and proposed the name of malignant GCOT. Expression profiling by cDNA microarrays is a molecular technology that enables a global gene expression analysis. By using cDNA microarrays, we identified in malignant GCOT several genes with significantly differentially regulated genes when compared to non neoplastic tissues. These cancer specific genes include a range of functional activities: (1) transcription, (2) signaling transduction, (3) cell-cycle regulation, (4) apoptosis, (5) differentiation and (6) angiogenesis. In conclusion, we show that cDNA microarrays is a useful approach to investigate the biology of tumours. Moreover, this technology might lead to identification of gene targets for cancer therapy and to molecular classification of odontogenic tumours.

Adult↗

Genetic expression profiling of six odontogenic tumors.

Odontogenic tumors are rare neoplasms arising from the odontogenic apparatus. We aimed to identify molecular characteristics associated with odontogenic tumorigenesis and malignancy. To this end, we investigated the expression level of human genes by using, for the first time in odontogenic tumors, the technique of expression profiling. Gene expression alterations common to all six odontogenic tumors were identified by the use of cDNA microarrays containing 19,000 human cDNAs. Statistical analysis on a subset of 4974 cDNAs present in the biopsies identified 506 distinct genes associated with the tumors (p-value < 0.01). Gene ontology analysis of the cellular processes which were differentially regulated in odontogenic tumors was accomplished by the use of a subset of 1409 annotated genes. Finally, 43 cDNAs differentiated the three malignant odontogenic tumors (ameloblastic carcinoma, clear cell odontogenic tumor, granular cell odontogenic tumor) from the three benign ameloblastoma biopsies (p < 0.01). The identified genes might help us better classify borderline odontogenic tumors.

Ameloblastoma↗

Chick embryo back skin organ and fibroblast cultures. Extracellular matrix changes induced by dialysate fluid and uraemic toxins in relation to proliferation and differentiation processes.

AIM: During uraemia, an increase of middle molecules and acetylpolyamines occurs. In vitro the middle molecules produce cell toxicity, while the acetylpolyamines stimulate cell proliferation and differentiation. These phenomena are related to protein and extracellular glycosaminoglycan production. The aim of the present study was to evaluate the activity of dialysate, dialysate fluid and the chromatographic peaks of dialysate fractionated by G-15 Sephadex column on chick embryo skin development. METHODS: We evaluated the effects of protein and glycosaminoglycan synthesis using monolayer and organotypic cultures. RESULTS: Our data show that dialysate, chromatographic peak II, and 2 x 10(-8)M N1-acetylspermine cause inhibition of chick embryo skin culture development. On the contrary, 10(-8)M N-acetylornithine and dialysate fluid increase protein and extracellular glycosaminoglycan synthesis, whereas chromatographic peak I does not reveal differences when compared to controls. CONCLUSIONS: These extracelluar changes are related to cell proliferation and feather formation in chick embryo organotypic culture. Moreover, the pH changes of culture medium do not influence the biological action of acetylpolyamines and dialysate fluid on protein and extracellular glycosaminoglycan synthesis. Cell death in the presence of N1-acetylspermine, dialysate and peak II appears unrelated to the apoptotic process. The data show that acetylpolyamines, dialysis fluid, dialysate and chromatographic peaks act on fibroblasts, and are able to modify glycosaminoglycan synthesis. The organotypic cultures of chick embryo back skin could represent a model for studying the modifications of the extracellular matrix induced by these substances.

Animals↗

Classification of oral clefts by affection site and laterality: a genotype-phenotype correlation study.

OBJECTIVES: The aim of this study was to classify the phenotypes found in a series of patients with non-syndromic cleft lip (CL) with or without cleft palate (CP) and isolated cleft palate. Additionally, the frequency distribution of cases belonging to families linked to markers on chromosomes 6 and 2 within these phenotypic patterns were estimated. DESIGN: A retrospective examination of all the available affected cases collected in Italy. SETTING AND SAMPLE POPULATION: Ninety-seven affected subjects aged 5-18 years belonging to 38 families were considered. Patterns were identified by variance of the cleft (lip, primary palate, secondary palate) and stratified according to the side of occurrence (right, left, or bilateral). Latent class analysis was used as main statistical tool for carrying out the results. RESULTS: Three homogenous classes were identified (P < 0.0001) by means of latent class analysis. Individuals were assigned to the most suited class. All three variables (lip, primary and secondary cleft palate) generated a specific class. Optimal findings were reported in cases having 'any isolated cleft lip' (class 1); 'secondary CP with or without bilateral/right primary cleft palate + bilateral/right cleft lip' (class 2); and 'left primary cleft palate + left/bilateral cleft lip with or without secondary CP' (class 3). Correspondence to the evidence of linkage to chromosome 6 showed that 9 of 10 cases presenting with 'right primary CP + right CL with secondary cleft palate' (class 2) belonged to a linked family. The same combination, but occurring on the left side (class 3), revealed that only three of nine cases belong to families linked to chromosome 6 (P-value = 0.02). The two patterns (right and left) never occurred in the same family. Three reliable groups were identified based on laterality and the presence of a cleft. A single right sided pattern displayed a statistically different distribution of linkage to chromosome 6 when compared with the homologous left side. CONCLUSION: Non-syndromic CL with/without CP can be classified according to laterality that can be under genetic control.

Adolescent↗

Modulation of gene expression in human osteoblasts by targeting a distal promoter region of human estrogen receptor-alpha gene.

Estrogen receptor (ER) alpha is expressed during osteoblast differentiation; however, both its functional role in bone metabolism and its involvement in osteoporotic pathogenesis caused by estrogen deficiency are not well understood. Loss of ER alpha gene expression could be one of the mechanisms leading to osteoporosis. Therefore, we investigated a possible modulation of ER alpha gene expression in a human osteoblastic cell line and in four primary osteoblast cultures by using a decoy strategy. Double stranded DNA molecules, mimicking a regulatory region of the ER alpha gene promoter (DNA-102) and acting as a 'silencer' in breast cancer cells, were introduced into osteoblasts as 'decoy' cis-elements to bind and functionally inactivate a putative negative transcription factor, and thus to induce ER alpha gene expression. We found that the DNA-102 molecule was able to specifically bind osteoblast nuclear proteins. Before decoy treatment, absence or variable low levels of ER alpha RNAs in the different cultures were detected. When the cells were transfected with the DNA-102 decoy, an increase in expression of ER alpha and osteoblastic markers, such as osteopontin, was observed, indicating a more differentiated osteoblastic phenotype both in the cell line and in primary cultures. These results showed that the DNA-102 sequence competes with endogenous specific negative transcription factors that may be critical for a decrease in or lack of ER alpha gene transcription. Therefore, osteoblastic transfection with the DNA-102 decoy molecule may be considered a tempting model in a putative therapeutic approach for those pathologies, such as osteoporosis, in which the decrease or loss of ER alpha expression plays a critical role in bone function.

Biomarkers↗

C677T variant form at the MTHFR gene and CL/P: a risk factor for mothers?

Maternal folic acid supplementation in early pregnancy has been suggested to play a role in the prevention of nonsyndromic orofacial cleft, i.e., cleft lip with or without cleft palate (CL/P). Moreover, some authors demonstrated association of the C-->T mutation (C677T), converting an alanine to a valine residue in 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, with other congenital anomalies such as neural tube defects (NTDs). Because of MTHFR's involvement in the metabolism of folate, we investigated 64 CL/P patients and their parents for C677T MTHFR mutation. No linkage disequilibrium was found using the transmission disequilibrium test (TDT). However, a significantly higher mutation frequency was detected in mothers of CL/P patients compared to controls. The odds ratios calculated for mothers having CT or TT genotype, compared to the normal CC genotype, were 2.75 (95% confidence interval 1.30-5.57) and 2.51 (1.00-6.14), respectively. These results support the involvement of the folate pathway in the etiology of CL/P, and indicate an effect of the maternal genotype, rather than influence of the embryo's genotype.

Alleles↗

Linkage analysis of three candidate regions of chromosome 1 in nonsyndromic familial orofacial cleft.

Linkage analysis and mouse model knockout studies indicate that loci/genes mapping in different chromosome 1 regions are good candidates for nonsyndromic orofacial cleft (OFC) malformation. On this basis, three different regions of the chromosome 1 have been analysed, by linkage analysis, in 38 families with nonsyndromic OFC. Positive scores were obtained by pairwise analysis and a non-parametric linkage approach for the 1p36 region, with markers close to the MTHFR locus. Additional results allowed us to exclude the presence of an OFC susceptibility gene in the 1q21 and 1q32-42.3 regions.

Chromosomes, Human, Pair 1↗

Effects of pulsed electromagnetic fields on human articular chondrocyte proliferation.

Low-energy, low-frequency pulsed electromagnetic fields (PEMFs) can induce cell proliferation in several cell culture models. In this work we analysed the proliferative response of human articular chondrocytes, cultured in medium containing 10% FBS, following prolonged exposure to PEMFs (75 Hz, 2.3 mT), currently used in the treatment of some orthopaedic pathologies. In particular, we investigated the dependence of the proliferative effects on the cell density, the availability of growth factors and the exposure lengths. We observed that PEMFs can induce cell proliferation of low density chondrocyte cultures for a long time (6 days), when fresh serum is added again in the culture medium. In the same conditions, in high density cultures, the PEMF-induced increase in cell proliferation was observed only in the first three days of exposure. The data presented in this study show that the availability of growth factors and the environmental constrictions strongly condition the cellular proliferative response to PEMFs.

Aged↗

Interleukin secretion, proteoglycan and procollagen alpha(1)(I) gene expression in Crouzon fibroblasts treated with basic fibroblast growth factor.

The present study provides the first evidence that fibroblasts obtained from patients affected by Crouzon syndrome, a rare craniosynostosis, despite mutations in the high-affinity bFGF receptor retain their capacity to respond to bFGF. The growth factor reduces IL-1 secretion, downregulates biglycan and procollagen alpha(1)(I), and increases betaglycan expression. Since betaglycan is a co-receptor for bFGF signalling, an alternative signal transduction pathway is suggested in Crouzon fibroblasts, to explain the documented changes in ECM macromolecule production.

Adolescent↗

Linkage analysis of candidate endothelin pathway genes in nonsyndromic familial orofacial cleft.

There is good evidence from linkage analysis and mouse model knockouts that the endothelin-1 gene (EDN1) is a good candidate for non-syndromic orofacial cleft (OFC) disease. EDN1 maps to the chromosomal region of the OFC1 locus in 6p23. Therefore we have examined three other candidate genes in the endothelin pathway (ECE1, EDNRA and EDNRB, which map to chromosomes 1, 4 and 13 respectively) in a linkage study of 9 families with OFC, where the disorder is not linked to chromosome 6p23. The total lod score for these 9 multiplex families never exceeded -2.00 and thus our data suggest that EDN1 and related genes are not involved in non-syndromic familial OFC.

Animals↗

Genetics of nonsyndromic cleft lip and palate: a review of international studies and data regarding the Italian population.

The aims of this review are (1) to illustrate current knowledge of the mode of inheritance and the loci involved in the cleft lip and palate and (2) to summarize the results of our investigations, which were carried out in Italy. It is well established that nonsyndromic cleft of the lip with or without the palate (CL+/-P) and cleft palate only (CPO) are separate entities. Genetic heterogeneity has been observed in CL+/-P, which involves different chromosome regions, mainly 6p23 (OFC1), 2q13 (OFC2), and 19q13.2 (OFC3), as well as other loci, such as 4q25-4q31.3 and 17q21. Furthermore, an interaction between different genes has been suggested in the oligogenic model. In one case at least, an OFC1 and OFC2 interaction has been demonstrated. The mode of inheritance of CPO is compatible with a recessive single major gene model, while an association with a candidate gene, mapping on the chromosome region 2q13/TGFalpha, remains to be confirmed.

Animals↗

Correlation between pulsed electromagnetic fields exposure time and cell proliferation increase in human osteosarcoma cell lines and human normal osteoblast cells in vitro.

We have exposed cultured bone cells to a pulsed electromagnetic field (PEMF) for different times to find the minimal exposure time necessary to stimulate an increase of DNA synthesis. We used two different human osteosarcoma cell lines, TE-85 and MG-63, and human normal osteoblast cell (NHOC) obtained from surgical bone specimens. The cells were placed in multiwell plates and set in a tissue culture incubator between a pair of Helmoltz coils powered by a pulse generator (1.3-ms pulse, repeated at 75 Hz) for different periods of time. [3H]Thymidine incorporation was used to evaluate cell proliferation. The two osteosarcoma cell lines increase their thymidine incorporation when exposed to a PEMF for at least 30 min, both in a medium containing 10% fetal calf serum and in a serum-free medium. NHOC are known to increase their cell proliferation when exposed to PEMF but only if cultured in the presence of 10% fetal calf serum. In this experimental condition, three of the four cell lineages studied required at least 9 h of PEMF exposure to increase their DNA synthesis, whereas one cell lineage increased its cell proliferation after 6 h of PEMF exposure. Our observations confirm the hypothesis that the proliferative responses of NHOC and human osteosarcoma cell lines to PEMF exposure are quite different. Moreover, NHOC required minimal exposure times to PEMF to increase their cell proliferation, similar to that needed to stimulate bone formation in vivo.

Adult↗

Effects of pulsed electromagnetic fields on human chondrocytes: an in vitro study.

(3)H-thymidine incorporation was studied in cultured human nasal and articular chondrocytes exposed to low-energy, low-frequency pulsed electromagnetic fields (PEMFs) (75 Hz, 2.3 mT). The reverse transcriptase polymerase chain reaction (RT-PCR) analysis shows that human secondary chondrocytes derived from both nasal and articular cartilage express collagen type II mRNA, which is a specific marker of the chondrocyte phenotype. In a preliminary series of experiments, cells were exposed to PEMF for different time periods ranging from 6 to 30 hours (time-course), in medium supplemented with 10% or 0.5% fetal calf serum (FCS) and in serum-free medium. The ratios between the (3)H-thymidine incorporation in PEMFs and control cultures show an increase of the cell proliferation in cultures exposed to PEMFs when serum is present in the culture medium, whereas no effect was observed in serum-free conditions. The increase in DNA synthesis, induced by PEMFs, was then evaluated only at the times of maximum induction and the results were analyzed by the three-factor analysis of variance (ANOVA). The data presented in this study show that even if (3)H-thymidine incorporation is higher in nasal than in articular chondrocytes, PEMF induce an increase in the proliferation of both cell types. Moreover, the concentration of FCS in the culture medium greatly influences the proliferative response of human chondrocytes to the PEMF exposure. Though normal human osteoblast cells increase their proliferation when exposed to PEMFs if only 10% FCS is present in the medium, human chondrocytes are able to increase their cell proliferation when exposed to PEMFs in the presence of both 0.5% and 10% of FCS in the medium. The results obtained may help to explain the basic mechanisms of PEMF stimulation of fracture healing.

Adolescent↗

Differential in vitro phenotype pattern, transforming growth factor-beta(1) activity and mRNA expression of transforming growth factor-beta(1) in Apert osteoblasts.

The phenotype of Apert osteoblasts differs from that of normal osteoblasts in the accumulation of macromolecules in the extracellular matrix. Apert osteoblasts increase type I collagen, fibronectin and glycosaminoglycans secretion compared with normal osteoblasts. Because the extracellular matrix macromolecule accumulation is greatly modulated by transforming growth factor-beta(1), we examined the ability of normal and Apert osteoblasts to secrete transforming growth factor-beta(1) by CCL-64 assay and to produce transforming growth factor-beta(1 )by analysis of the mRNA expression of transforming growth factor-beta(1). Northern blot analysis revealed an increased amount of transforming growth factor-beta(1) mRNA expression in Apert osteoblasts compared with normal ones. Moreover, the level of the active transforming growth factor-beta(1) isoform was higher in Apert than in normal media. In pathologic cells, the increase in transforming growth factor-beta(1) gene expression was associated with a parallel increase in the factor secreted into the medium. The level of transforming growth factor-beta(1) was decreased by the addition of basic fibroblast growth factor. Transforming growth factor-beta(1) is controlled temporally and spatially during skeletal tissue development and produces complex stimulatory and inhibitory changes in osteoblast functions. We hypothesise that in vitro differences between normal and Apert osteoblasts may be correlated to different transforming growth factor-beta(1) cascade patterns, probably due to an altered balance between transforming growth factor-beta(1) and basic fibroblast growth factor.

Acrocephalosyndactylia↗