In conclusion, our data indicate that EMD enhances human PDL fibroblast proliferation. Furthermore, the cells in the presence of EMD show morphological changes that make them more similar to cementoblasts than to fibroblasts, suggesting a process of cellular differentiation that could play an important role in periodontal tissue repair.

Hydrogen sulphide (H2S) is a newly discovered gasotransmitter that regulates multiple steps in VEGF-induced angiogenesis. An increase in intracellular Ca(2+) concentration ([Ca(2+)]i) is central to endothelial proliferation and may be triggered by both VEGF and H2S. Albeit VEGFR-2 might serve as H2S receptor, the mechanistic relationship between VEGF- and H2S-induced Ca(2+) signals in endothelial cells is unclear. The present study aimed at assessing whether and how NaHS, a widely employed H2S donor, stimulates pro-angiogenic Ca(2+) signals in Ea.hy926 cells, a suitable surrogate for mature endothelial cells, and human endothelial progenitor cells (EPCs). We found that NaHS induced a dose-dependent increase in [Ca(2+)]i in Ea.hy926 cells. NaHS-induced Ca(2+) signals in Ea.hy926 cells did not require extracellular Ca(2+) entry, while they were inhibited upon pharmacological blockade of the phospholipase C/inositol-1,4,5-trisphosphate (InsP3) signalling pathway. Moreover, the Ca(2+) response to NaHS was prevented by genistein, but not by SU5416, which selectively inhibits VEGFR-2. However, VEGF-induced Ca(2+) signals were suppressed by dl-propargylglycine (PAG), which blocks the H2S-producing enzyme, cystathionine γ-lyase. Consistent with these data, VEGF-induced proliferation and migration were inhibited by PAG in Ea.hy926 cells, albeit NaHS alone did not influence these processes. Conversely, NaHS elevated [Ca(2+)]i only in a modest fraction of circulating EPCs, whereas neither VEGF-induced Ca(2+) oscillations nor VEGF-dependent proliferation were affected by PAG. Therefore, H2S-evoked elevation in [Ca(2+)]i is essential to trigger the pro-angiogenic Ca(2+) response to VEGF in mature endothelial cells, but not in their immature progenitors.

Our experimental data suggest that acrolein and acetaldehyde, volatile components of tobacco smoke, are detrimental to HGF survival and consequently to the oral connective tissue. According to our morpho-functional evidence, these findings corroborate clinical and epidemiological investigations demonstrating smoke as a risk factor in the development of periodontal disease.

We studied the β-1,3-galactosyltransferase (GalT) and A-1,2-fucosyltansferase (FT) involved in the biosynthesis of type-1-chain carbohydrate antigens in human colon adenocarcinoma cell lines. We detected a GalT activity able to use GlcNAc as acceptor and found that lacto-N-biose I (Galβ1-3GlcNAc) is the only reaction product. Such β1,3GalT is kinetically similar to a pig trachea enzyme involved in mucin synthesis. The specific activity is high in cells that react strongly with anti-Lewis a and anti-Lewis b antibodies, and undetectable in a cell line that lacks antibody reaction. Reverse-transcriptase-mediated PCR analysis followed by DNA sequencing indicated that secretor-type A1,2FT is expressed in the cells, while the H type A1,2FT is not. The apparent K m values for donor and acceptor substrates determined for A1,2FT are similar to those of secretor-type A1,2FT and the specific activity measured correlates with Lewis b antigen expression on the cell surface. Moreover, some of the cell lines express Lewis y and H type 2 antigens, indicating that secretor type A1,2FT is responsible for their synthesis. Results suggest that biosynthesis of type-1-chain tumor-associated antigens in human colon carcinoma cells is operated by secretor-type A1,2FT, as reported in normal mucosa, and that β1,3GalT activity may play a relevant role in its control.Keywords : glycosyltransferase; carbohydrate antigen; colon carcinoma ; immunostaining.Association with tumor progression and malignancy has been reported for several carbohydrate antigens [1,2] and recent data suggest this is presumably due to their involvement in selectin-dependent tumor cell adhesion to the vascular endothelium [3,4]. Type-1-chain carbohydrate antigens such as SLe a (NeuAcA2-3Galβ1-3[FucA1-4]GlcNAc) and GlcNAc) are expressed in several cancers [1, 5Ϫ8]. Specific involvement of SLe a in selectin-dependent cell adhesion has been suggested [9, 10] and its stage-specific expression has been described in embryonic pancreas [11]. In the case of Le b, as well as in that of its type 2 chain counterpart Le y (FucA1-2Galβ1-4[FucA1-3]GlcNAc) [12,13], the molecular basis of their association with malignancy is still not fully elucidated.The biosynthesis of type-1-chain tumor markers depends on the activity of a galactosyltransferase (GalT) able to operate the Correspondence to

Mutations in the genes encoding for type V collagen have been found in the classical type of Ehlers-Danlos syndrome (EDS); the most common mutations lead to a non-functional COL5A1 allele. We characterized three skin fibroblast strains derived from patients affected by classical EDS caused by COL5A1 haploinsufficiency. As a typical clinical hallmark of EDS is the impaired wound healing, we analyzed the repair capability of fibroblasts in a monolayer wounding assay. The mutant fibroblast strains were unable to move into the scraped area showing then a marked delay in wound repair. In all the EDS strains, type V collagen was absent in the extracellular space, also leading to the lack of fibronectin fibrillar network and impairing the expression of alpha(2)beta(1) and alpha(5)beta(1) integrins. The abnormal integrin pattern inhibited the positive effect of insulin-like growth factor-binding protein-1 on cell migration, whereas the migratory capability remarkably improved in the presence of exogenous type V collagen.