Nerve growth factor (NGF) is the founding member of the polypeptide neurotrophin family responsible for neuronal differentiation. To determine whether the effects of NGF rely upon novel Integrative Nuclear FGF Receptor-1 (FGFR1) Signaling (INFS) we utilized the PC12 clonal cell line, a long-standing benchmark model of sympathetic neuronal differentiation. We demonstrate that NGF increases expression of the fgfr1 gene and promotes trafficking of FGFR1 protein from cytoplasm to nucleus by inhibiting FGFR1 nuclear export. Nuclear-targeted dominant negative FGFR1 antagonizes NGF-induced neurite outgrowth, doublecortin (dcx) expression and activation of the tyrosine hydroxylase (th) gene promoter, while active constitutive nuclear FGFR1 mimics the effects of NGF. NGF increases the expression of dcx, th, βIII tubulin, nurr1 and nur77, fgfr1and fibroblast growth factor-2 (fgf-2) genes, while enhancing binding of FGFR1and Nur77/Nurr1 to those genes. NGF activates transcription from isolated NurRE and NBRE motifs. Nuclear FGFR1 transduces NGF activation of the Nur dimer and raises basal activity of the Nur monomer. Cooperation of nuclear FGFR1 with Nur77/Nurr1 in NGF signaling expands the integrative functions of INFS to include NGF, the first discovered pluripotent neurotrophic factor.

Neurogenesis, the process of differentiation of neuronal stem/progenitor cells (NS/PC) into mature neurons, holds the key to the treatment of various neurodegenerative disorders, which are a major health issue for the world's aging population. We report that targeting the novel integrative nuclear FGF Receptor 1 signaling (INFS) pathway enhances the latent potential of NS/PCs to undergo neuronal differentiation, thus promoting neurogenesis in the adult brain. Employing organically modified silica (ORMOSIL)-DNA nanoplexes to efficiently transfect recombinant nuclear forms of FGFR1 and its FGF-2 ligand into the brain subventricular zone, we find that INFS stimulates the NS/PC to withdraw from the cell cycle, differentiate into doublecortin expressing migratory neuroblasts and neurons that migrate to the olfactory bulb, subcortical brain regions and in the brain cortex. Thus, nanoparticle-mediated non-viral gene transfer may be used to induce selective differentiation of NS/PCs, providing a potentially significant impact on the treatment of a broad range of neurological disorders.

A histological and histochemical analyses were carried out on the entire alimentary canal of the rainbow trout Oncorhynchus mykiss. In particular the oesophageal region showed presence of terminal b-D-galactose(1-3)-N-acetylgalactosamine and a-N-acetylgalactosamine. In the anterior and posterior regions of the stomach, lining epithelium and gastric pits exhibited the presence of b-gal and a-GalNAc. In addition sialoglycoconjugates having sialic acid-bgalactose(1-3)-N-acetylgalactosamine and sialic acid-N-acetylgalactosamine as terminal triand di-saccharides, were demonstrated. In proximal and distal intestine goblet cells showed the presence of sialoglyconjugates, having sialic acid-b-gal(1-3)-GalNAc and sialic acidGalNAc as terminal sequences, belonging to N-linked chains. In the enterocytes of the entire intestine, terminal GlcNAc, a-Gal, a-fucose were found. #

In this study, we investigated the role of prostaglandin F2alpha (PGF2alpha) in mouse osteoblast survival and the function of fibroblast growth factor 2 (FGF-2) and fibroblast growth factor receptor 1 (FGFR1) in this process. In particular, for the first time, we demonstrated that PGF2alpha increased osteoblast survival in a dose-dependent manner and we showed that the effect is correlated with an increase in Bcl-2/Bax ratio. Furthermore, we demonstrated that PGF2alpha caused a decrement of the active caspases 9 and 3. By blocking FGF-2 with the specific neutralizing antibody and by depletion of FGFR1 gene with a specific siRNA, we showed that FGFR1 and FGF-2 are critical for the increment of Bcl-2/Bax ratio and the decrement of the active caspases 9 and 3, induced by PGF2alpha. Moreover, transmission electron microscopy studies showed that PGF2alpha increased binding of FGF-2 and FGFR1 and co-localization of reactive sites at plasma membrane level. In conclusion, we report a novel mechanism in which PGF2alpha induces FGF-2 binding to its specific cell surface receptor 1 leading to a cascade pathway that culminates with increased mouse osteoblast survival.

The present investigation extends our previous studies on PGF2alpha-mediated signalling in osteoblast metabolism. In particular, the role of PGF2alpha as modulator of heparan sulphate proteoglycans (HSPGs), fibroblast growth factor 2 (FGF-2) and fibroblast growth factor receptors (FGFRs) was evaluated. We hereby reported the novel observation that PGF2alpha was able to promote the formation of HSPGs/FGF-2/FGFRs complexes. Moreover, our data suggested that PGF2alpha could induce new synthesis of heparan sulphate (HS) chains on osteoblasts by a mechanism involving a modulation of MAPK signalling and that HS is required for the regulation of FGF-2 induced by PGF2alpha. Indeed, a proteolytic cleavage of HSPGs with heparinase III (Hep III) prior to PGF2alpha administration down-regulated the basal expression of phospho-p44/42, likely inhibiting FGFRs tyrosine kinase activity. Interestingly, MAPK signalling influenced syntheses and subcellular localization of FGF-2, its specific receptor and HS. In addition, the proteolytic cleavage by Hep III and the MAPK kinase inhibition by PD-98059 also revealed that PGF2alpha induced cell proliferation is dependent on HSPGs and FGF-2 specific receptor, respectively. Of further relevance of this study, we demonstrated, by using a specific siRNA for FGFR1, that PGF2alpha modulates Runx2 expression by FGFR1 and HS.

We previously reported that transient administration of phthalates induced actin cytoskeleton disruption in Py1a osteoblasts. However, the mechanism of this transient effect was not elucidated. In this study we provided evidence that the actin cytoskeletal re-established conditions are dependent on new actin expression and synthesis. To assess the role of phthalates in modulating the distribution of actin, confocal and electron microscopy studies were carried out. Results indicated a modification of actin distribution after phthalate administration. In addition, a relation with the nucleoskeletal component lamin A supports the hypothesis that phthalates may participate in regulatory cell processes involving actin in Py1a osteoblasts. The present study also supports the mitogenic effects of phthalates, which involve microfilament disruption, nuclear actin and lamin A. In particular, the increased levels of cyclin D3, which in mammalian cells plays a critical role in G1 to S transition and is a putative proto-oncogene in benzyl butyl phthalate treated cells, suggested a possible effect of the endocrine disruptor in cancer processes.