The subventricular zone produces neuroblasts that migrate to the olfactory bulb (OB) and differentiate into interneurons throughout postnatal life (Altman and Das, 1966; Hinds, 1968; Altman, 1969; Kishi et al., 1990; Luskin, 1993; Lois and Alvarez-Buylla, 1994). Although such postnatally generated interneurons have been characterized morphologically, their physiological differentiation has not been thoroughly described. Combining retroviral-mediated labeling of newly generated neurons with patch-clamp electrophysiology, we demonstrated that soon after new cells enter the layers of the olfactory bulb, they display voltage-dependent currents typical of more mature neurons. We also show that these "newcomers" express functional GABA and glutamate receptor channels, respond synaptically to stimulation of the olfactory nerve, and may establish both axodendritic and dendrodendritic synaptic contacts within the olfactory bulb. These data provide a basic description of the physiology of newly generated cells in the OB and show that such new cells are functional neurons that synaptically integrate into olfactory bulb circuitry soon after their arrival.

Like most human neoplasm, breast cancer has aberrations in signal transduction elements that can lead to increased proliferative potential, apoptosis inhibition, tissue invasion and metastasis. Due to the high heterogeneity of this tumor, currently, no markers are clearly associated with the insurgence of breast cancer, as well as with its progression from in situ lesion to invasive carcinoma. We have recently demonstrated an altered expression of the beta2 isoform of the phosphoinositide-dependent phospholipase C (PLC) in invasive breast tumors with different histopathological features. In primary breast tumor cells, elevated amounts of this protein are closely correlated with a poor prognosis of patients with mammary carcinoma, suggesting that PLC-beta2 may be involved in the development and worsening of the malignant phenotype. Here we demonstrate that PLC-beta2 may improve some malignant characteristics of tumor cells, like motility and invasion capability, but it fails to induce tumorigenesis in non-transformed breast-derived cells. We also report that, compared with the G(0)/G(1) phases of the cell cycle, the cells in S/G(2)/M phases show high PLC-beta2 expressions that reach the greatest levels during the late mitotic stages. In addition, even if unable to modify the proliferation rate and the expression of cell cycle-related enzymes of malignant cells, PLC-beta2 may promote the G(2)/M progression, a critical event in cancer evolution. Since phosphoinositides, substrates of PLC, are involved in regulating cytoskeleton architecture, PLC-beta2 in breast tumor cells may mediate the modification of cell shape that characterizes cell division, motility and invasion. On the basis of these data, PLC-beta2 may constitute a molecular marker of breast tumor cells able to monitor the progression to invasive cancers and a target for novel therapeutic breast cancer strategies.

Overexpression of Vav1 promotes the overcoming of the differentiation blockade that characterizes acute promyelocytic leukemia cells. At variance, down-modulation of Vav1 prevents ATRA-induced maturation, and in particular, the inhibition of its tyrosine phosphorylation prevents the neutrophil differentiation-related changes of cell morphology. These findings allowed to identify Vav1 as a crucial protein in the ATRA-dependent differentiation of tumoral promyelocytes. By means of a proteomic approach, here we have investigated a possible role for Vav1 in modulating protein expression during ATRA treatment of tumoral promyelocytes. We have performed high-resolution 2-DE coupled with mass spectra analysis of HL-60 and NB4 promyelocytic cell lines induced to differentiate with ATRA when the amounts or the tyrosine phosphorylation of Vav1 were forcedly reduced. We have found that the down-regulation of Vav1 affects the expression level of a number of proteins, including cell cycle/apoptosis- and cytoskeleton-related proteins. In particular, the expression of 14-3-3epsilon, alpha-enolase, alpha-tubulin and splice isoform 2 of alpha3 proteasome subunit changed as a consequence of the down-modulation of Vav1 during the differentiation of both HL-60 and NB4 cell lines, suggesting that these proteins may constitute a common part of the ATRA-induced pathway during maturation of APL-derived promyelocytes. These results indicate an unprecedented role for Vav1 in the maturation of myeloid cells as a regulator of protein expression.

Mucus form H. aspersa muller has been reported to have several therapeutic proprieties, such as antimicrobial activity, skin protection and wound repair. In this study, we have analyzed H. aspersa mucus (Helixcomplex) bio-adhesive efficacy and its defensive properties against the ozone (O 3) (0.5 ppm for 2 hours) exposure in human keratinocytes and reconstructed human epidermis models. Cytotoxicity, tissue morphology and cytokine levels were determined. We confirmed HelixComplex regenerative and bio-adhesive properties, the latter possibly via the characteristic mucopolysaccharide composition. In addition, Helix-Complex was able to protect from O 3 exposure by preventing oxidative damage and the consequent pro-inflammatory response in both 2D and 3D models. Based on this study, it is possible to suggest HelixComplex as a potentially new protective technology against pollution induced skin damage.