Latest PUBLICATIONS

  • Clinical and molecular genetics of Leber's congenital amaurosis: a multicenter study of Italian patients.
    Publication Date: 01/09/2007, on Investigative ophthalmology & visual science
    by Simonelli F, Ziviello C, Testa F, Rossi S, Fazzi E, Bianchi PE, Fossarello M, Signorini S, Bertone C, Galantuomo S, Brancati F, Valente EM, Ciccodicola A, Rinaldi E, Auricchio A, Banfi S
    DOI: 10.1167/iovs.07-0068

    To identify the molecular basis of Leber's congenital amaurosis (LCA) in a cohort of Italian patients and to perform genotype-phenotype analysis.

  • Synthesis and evaluation of human T cell stimulating activity of an alpha-sulfatide analogue.
    Publication Date: 15/08/2007, on Bioorganic & medicinal chemistry
    by Franchini L, Matto P, Ronchetti F, Panza L, Barbieri L, Costantino V, Mangoni A, Cavallari M, Mori L, De Libero G
    DOI: 10.1016/j.bmc.2007.05.044

    A concise synthesis of alpha-sulfatide 1, an analogue of natural glycolipid antigens with potential anti-tumor activity, was performed. Two different approaches to the alpha-glycosidic bond were explored, resulting in a high yield and excellent stereoselectivity. Compound 1 combines the structural features of sulfated beta-GalCer (sulfatide) and alpha-GalCer, which activate specific T cells. alpha-Sulfatide 1 was stimulatory for CD1d-restricted semi-invariant Natural Killer T (iNKT) cell clones, although less potent than alpha-GalCer, while it was not recognized by CD1a-restricted sulfatide-specific T cells.

  • Brg1 chromatin remodeling factor is involved in cell growth arrest, apoptosis and senescence of rat mesenchymal stem cells.
    Publication Date: 15/08/2007, on Journal of cell science
    by Napolitano MA, Cipollaro M, Cascino A, Melone MA, Giordano A, Galderisi U
    DOI: 10.1242/jcs.004002

    Self-renewal, proliferation and differentiation properties of stem cells are controlled by key transcription factors. However, their activity is modulated by chromatin remodeling factors that operate at the highest hierarchical level. Studies on these factors can be especially important to dissect molecular pathways governing the biology of stem cells. SWI/SNF complexes are adenosine triphosphate (ATP)-dependent chromatin remodeling enzymes that have been shown to be required for cell cycle control, apoptosis and cell differentiation in several biological systems. The aim of our research was to investigate the role of these complexes in the biology of mesenchymal stem cells (MSCs). To this end, in MSCs we caused a forced expression of the ATPase subunit of SWI/SNF (Brg1 - also known as Smarca4) by adenoviral transduction. Forced Brg1 expression induced a significant cell cycle arrest of MSCs in culture. This was associated with a huge increase in apoptosis that reached a peak 3 days after transduction. In addition, we observed signs of senescence in cells having ectopic Brg1 expression. At the molecular level these phenomena were associated with activation of Rb- and p53-related pathways. Inhibition of either p53 or Rb with E1A mutated proteins allowed us to hypothesize that both Rb and p53 are indispensable for Brg1-induced senescence, whereas only p53 seems to play a role in triggering programmed cell death. We also looked at the effects of forced Brg1 expression on canonical MSC differentiation in adipocytes, chondrocytes and osteocytes. Brg1 did not induce cell differentiation per se; however, this protein could contribute, at least in part, to the adipocyte differentiation process. In conclusion, our results suggest that whereas some ATP-dependent chromatin remodeling factors, such as ISWI complexes, promote stem cell self-renewal and conservation of an uncommitted state, others cause an escape from 'stemness' and induction of differentiation along with senescence and cell death phenomena.

  • Characterization of the properties and trafficking of an anchorless form of the prion protein.
    Publication Date: 03/08/2007, on The Journal of biological chemistry
    by Campana V, Caputo A, Sarnataro D, Paladino S, Tivodar S, Zurzolo C
    DOI: 10.1074/jbc.M701468200

    Conversion of PrP(C) into PrP(Sc) is the central event in the pathogenesis of transmissible prion diseases. Although the molecular basis of this event and the intracellular compartment where it occurs are not yet understood, the association of PrP with cellular membranes and in particular its presence in detergent-resistant microdomains appears to be of critical importance. In addition it appears that scrapie conversion requires membrane-bound glycosylphosphatidylinositol (GPI)-linked PrP. The GPI anchor may affect either the conformation, the intracellular localization, or the association of the prion protein with specific membrane domains. However, how this occurs is not known. To understand the relevance of the GPI anchor for the cellular behavior of PrP, we have studied the biosynthesis and localization of a PrP version which lacks the GPI anchor attachment signal (PrP Delta GPI). We found that PrP Delta GPI is tethered to cell membranes and associates to membrane detergent-resistant microdomains but does not assume a transmembrane topology. Differently to PrP(C), this protein does not localize at the cell surface but is mainly released in the culture media in a fully glycosylated soluble form. The cellular behavior of anchorless PrP explains why PrP Delta GPI Tg mice can be infected but do not show the classical signs of the disorder, thus indicating that the plasma membrane localization of PrP(C) and/or of the converted scrapie form might be necessary for the development of a symptomatic disease.

  • Object-based neglect for the near peripersonal space in drawing tasks.
    Publication Date: 01/08/2007, on European journal of neurology
    by Grossi D, Esposito D, Cuomo C, Conchiglia G, Trojano L
    DOI: 10.1111/j.1468-1331.2007.01690.x

    We report a patient with a right cortical and subcortical temporo-occipital lesion who showed spatial neglect mainly involving the left and the near peripersonal space. In drawing tasks the patient omitted the elements closer to him within each figure. A copying task with pairs of radially aligned line drawings demonstrated that the patient's radial neglect was based on within-object coordinates. This novel observation extends the egocentric-allocentric distinction to the radial dimension.

  • The influence of pomegranate fruit extract in comparison to regular pomegranate juice and seed oil on nitric oxide and arterial function in obese Zucker rats.
    Publication Date: 01/08/2007, on Nitric oxide : biology and chemistry
    by de Nigris F, Balestrieri ML, Williams-Ignarro S, D'Armiento FP, Fiorito C, Ignarro LJ, Napoli C
    DOI: 10.1016/j.niox.2007.04.005

    Metabolic syndrome includes most widely distributed clinical conditions such as obesity, hypertension, dislipidemia, and diabetes. Pomegranate fruit extract (PFE), rich in polyphenolic antioxidants, reduces the expression of oxidation-sensitive genes at the sites of perturbed shear-stress. The aim of this study was to evaluate the effect of PFE in comparison to regular pomegranate juice (PJ) and seed oil on the biological actions of nitric oxide (NO) and the arterial function in obese Zucker rats, a model of metabolic syndrome. Our results indicated that supplementation with PFE or PJ significantly decreased the expression of vascular inflammation markers, thrombospondin (TSP), and cytokine TGFbeta1 (P<0.05), whereas seed oil supplementation had a significant effect only on TSP-1 expression (P <0.05). Plasma nitrate and nitrite (NO(x)) levels were significantly increased by PFE and PJ (P<0.05). Furthermore, the effect of PFE in increasing endothelial NO synthase (eNOS) expression was comparable to that of PJ. These data highlight possible clinical applications of PFE in metabolic syndrome.

  • GDNF signaling in embryonic midbrain neurons in vitro.
    Publication Date: 23/07/2007, on Brain research
    by Consales C, Volpicelli F, Greco D, Leone L, Colucci-D'Amato L, Perrone-Capano C, di Porzio U
    DOI: 10.1016/j.brainres.2007.04.071

    The glial cell line-derived neurotrophic factor (GDNF) exerts trophic actions on a number of cell types, including mesencephalic dopaminergic (mDA) neurons. Using rat mesencephalic primary cultures enriched in mDA neurons, we show that protracted GDNF stimulation increases their survival and neurite outgrowth. It modulates the expression of genes essential for DA function (tyrosine hydroxylase, TH and dopamine transporter, dat) and of DA high affinity uptake. To identify genes involved in GDNF signaling pathways, we have used DNA microarray on mDA cultures stimulated with GDNF for 3 h. Here we show that GDNF signaling sequentially activates the genes encoding for the transcription factors EGR1 and TIEG. In addition, it increases the expression of cav1, which encodes for the major component of caveolae. GDNF also modulates the expression of the genes encoding for the Calcineurin subunits ppp3R1 and ppp3CB, and inhibits calcium-calmodulin-dependent protein kinase II beta isoform (CaMKIIbeta) gene expression. These proteins are involved in neuronal differentiation and synaptic plasticity. Moreover, GDNF stimulation down regulates the expression of the glycogen synthase kinase 3beta (gsk3beta) gene, involved in neuronal apoptosis. Using inhibitors of specific intracellular signal transduction pathways we show that changes of egr1, tieg, cav1, CaMkIIbeta and gsk3beta genes expression are extracellular-signal regulated kinases 1/2 (ERK)-dependent, while the cAMP-dependent protein kinase (PKA) pathway influences the up-regulation of ppp3R1 and ppp3CB gene expression. These results demonstrate that GDNF stimulation results in the transcriptional modulation of genes involved in neuronal plasticity and survival and in mDA function, mediated in part by ERK and PKA signaling.

  • Highly variable penetrance in subjects affected with cavernous cerebral angiomas (CCM) carrying novel CCM1 and CCM2 mutations.
    Publication Date: 05/07/2007, on American journal of medical genetics. Part B, Neuropsychiatric genetics : the official publication of the International Society of Psychiatric Genetics
    by Gianfrancesco F, Cannella M, Martino T, Maglione V, Esposito T, Innocenzi G, Vitale E, Liquori CL, Marchuk DA, Squitieri F
    DOI: 10.1002/ajmg.b.30381

    Cavernous vascular malformations may affect brain and out-of-brain tissues. In most cases, cerebral cavernous malformations (CCMs) involve the brain alone, and are rarely associated with skin hemangiomas, spinal cord, retinal, hepatic or vertebral lesions. CCMs can cause seizures, intracranial and spinal haemorrhages, focal neurological deficits, and migraine-like headaches. After collecting CCM families of Italian origin and investigating the genetic basis of the disorder we disclosed two novel molecular variations in the KRIT1 and MGC4607 genes. We found a novel CCM1 gene mutation (Q66X) in a family with apparently asymptomatic old-aged mutation carriers and patients who either had skin angiomas alone or the full association of cerebral, spinal, and skin lesions. In this family we report the highest variability in mutation penetrance so far described, including the presence of CCM in one subject since birth (surgery at 19 months of age), a condition to our knowledge so far unreported. In a CCM2 affected family, we also report a novel causative mutation, (54_55delAC) in exon 2 of the MGC4607 gene, that produces a truncated protein containing only 22 amino acids. These data describe novel CCM mutations associated with a particularly high variability of the penetrance causing, in some cases, reduced expression of clinical symptoms and sporadic cases with apparent negative family history. Hence they emphasize the importance of DNA-based diagnostics and genetic counseling to identify unaffected mutation carriers subjects, even at advanced age.

  • Bdnf gene is a downstream target of Nurr1 transcription factor in rat midbrain neurons in vitro.
    Publication Date: 01/07/2007, on Journal of neurochemistry
    by Volpicelli F, Caiazzo M, Greco D, Consales C, Leone L, Perrone-Capano C, Colucci D'Amato L, di Porzio U
    DOI: 10.1111/j.1471-4159.2007.04494.x

    The transcription factor Nurr1 is essential for the generation of midbrain dopaminergic neurons (mDA). Only a few Nurr1-regulated genes have so far been identified and it remains unclear how Nurr1 influences the development and function of dopaminergic neurons. To identify novel Nurr1 target genes we have used genome-wide expression profiling in rat midbrain primary cultures, enriched in dopaminergic neurons, following up-regulation of Nurr1 expression by depolarization. In this study we demonstrate that following depolarization the hyperexpression of Nurr1 and the brain derived neurotrophic factor (BDNF) are phospholipase C- and protein kinase C-dependent. We show that Bdnf, which encodes a neurotrophin involved also in the phenotypic maturation of mDA neurons, is a novel Nurr1 target gene. By RNA interference experiments we show that a decreased Nurr1 expression is followed by tyrosine hydroxylase and BDNF mRNA and protein down-regulation. Reporter gene assay experiments performed on midbrain primary cultures using four Bdnf promoter constructs show that Bdnf is a direct target gene of Nurr1. Taken together, our findings suggest that Nurr1 might also influence the development and the function of midbrain dopaminergic neurons via direct regulation of Bdnf expression.

  • 5'-Modified G-quadruplex forming oligonucleotides endowed with anti-HIV activity: synthesis and biophysical properties.
    Publication Date: 01/07/2007, on Bioconjugate chemistry
    by D'Onofrio J, Petraccone L, Erra E, Martino L, Fabio GD, Napoli LD, Giancola C, Montesarchio D
    DOI: 10.1021/bc070062f

    Oligodeoxyribonucleotides of sequence d(5'TGGGAG3') carrying bulky aromatic groups at the 5' end were found to exhibit potent anti-HIV activity [Hotoda, H., et al. (1998) J. Med. Chem. 41, 3655-3663 and references therein]. Structure-activity relationship investigations indicated that G-quadruplex formation, as well as the presence of large aromatic substituents at the 5'-end, were both essential for their antiviral activity. In this work, we synthesized some representative examples of the anti-HIV active Hotoda's 6-mers and analyzed the resulting G-quadruplexes by CD, DSC, and molecular modeling studies, in comparison with the unmodified oligonucleotide. In the case of the sequence carrying the 3,4-dibenzyloxybenzyl (DBB) group, identified as the best candidate for further drug optimization, we developed an alternative protocol to synthesize the 5'-DBB-thymidine phosphoramidite building block in higher yields. The thermodynamic and kinetic parameters for the association/dissociation processes of the 5'-conjugated quadruplexes, determined with respect to the unmodified one, were discussed in light of the molecular modeling studies. The aromatic groups at the 5' position of d(5'TGGGAG3') dramatically enhance both the equilibrium and the rate of formation of the quadruplex complexes. The overall stability of the investigated quadruplexes was found to correlate with the reported IC50 values, thus furnishing quantitative evidence for the hypothesis that the G-quadruplex structures are the ultimate active species, effectively responsible for the biological activity.

  • A rare symptomatic presentation of ecchordosis physaliphora: neuroradiological and surgical management.
    Publication Date: 01/06/2007, on Journal of neurology, neurosurgery, and psychiatry
    by Rotondo M, Natale M, Mirone G, Cirillo M, Conforti R, Scuotto A
    DOI: 10.1136/jnnp.2006.109561

    We report a case of ecchordosis physaliphora, an uncommon benign lesion originating from embryonic notochordal remnants, intradurally located in the prepontine cistern, that unusually presented associated with symptoms. MRI detected and precisely located the small mass. At surgery, a cystic gelatinous nodule was found ventral to the pons, contiguous with the dorsal wall of the clivus via a small pedicle. Histological examination diagnosed the lesion as an ecchordosis physaliphora. Here we focus on the analysis of the neuroradiological aspects that play a crucial role from both a diagnostic and a therapeutic standpoint.

  • Sulfatase modifying factor 1 trafficking through the cells: from endoplasmic reticulum to the endoplasmic reticulum.
    Publication Date: 16/05/2007, on The EMBO journal
    by Zito E, Buono M, Pepe S, Settembre C, Annunziata I, Surace EM, Dierks T, Monti M, Cozzolino M, Pucci P, Ballabio A, Cosma MP
    DOI: 10.1038/sj.emboj.7601695

    Sulfatase modifying factor 1 (SUMF1) is the gene mutated in multiple sulfatase deficiency (MSD) that encodes the formylglycine-generating enzyme, an essential activator of all the sulfatases. SUMF1 is a glycosylated enzyme that is resident in the endoplasmic reticulum (ER), although it is also secreted. Here, we demonstrate that upon secretion, SUMF1 can be taken up from the medium by several cell lines. Furthermore, the in vivo engineering of mice liver to produce SUMF1 shows its secretion into the blood serum and its uptake into different tissues. Additionally, we show that non-glycosylated forms of SUMF1 can still be secreted, while only the glycosylated SUMF1 enters cells, via a receptor-mediated mechanism. Surprisingly, following its uptake, SUMF1 shuttles from the plasma membrane to the ER, a route that has to date only been well characterized for some of the toxins. Remarkably, once taken up and relocalized into the ER, SUMF1 is still active, enhancing the sulfatase activities in both cultured cells and mice tissues.

  • Pathophysiology of stem cells in restenosis.
    Publication Date: 01/05/2007, on Histology and histopathology
    by Forte A, Cipollaro M, Cascino A, Galderisi U
    DOI: 10.14670/HH-22.547

    Recent evidence has shown that vascular function depends not only on cells within the vessels, but is also significantly modulated by circulating cells derived from the bone marrow. A number of studies indicate that an early reendothelialization by circulating endothelial precursors after vascular injury prevents excessive cell proliferation and restenosis. Conversely, other studies concluded that the homing of other cell fractions, consisting mainly of smooth muscle precursors, cause pathological remodelling. Different cell types have been identified and characterized so far as circulating precursors able to participate in vascular repair by homing and differentiating towards endothelial cells or smooth muscle cells. Among these, endothelial precursor cells, smooth muscle progenitor cells, mesenchymal stem cells and others have been described. The origins, the hierarchy, the role and the markers of these different cell populations are still controversial. Nevertheless, different strategies have been developed so far in animal models to induce the mobilization and the recruitment of stem cells to the injury site, based on physical training, hormone injection and application of stem cell-capturing coated stents. It should also be mentioned that the limited data currently available derived from clinical trials provide contrasting results about the effective role of vascular cell precursors in restenosis prevention, thus indicating that conclusions derived from studies in animal models cannot always be directly applied to humans and that caution should be used in the manipulation of circulating progenitor cells for therapeutic strategies.

  • Novel challenges in exploring peptide ligands and corresponding tissue-specific endothelial receptors.
    Publication Date: 01/05/2007, on European journal of cancer (Oxford, England : 1990)
    by Balestrieri ML, Napoli C
    DOI: 10.1016/j.ejca.2007.02.006

    The structural and molecular diversity of vascular endothelium may depend on the functional state and tissue localisation of its cells. Tumour vasculature expresses a number of molecular markers that distinguish it from normal vasculature. In cancer, the determinant of specific tumour vasculature heterogeneity is, in part, dictated by dysregulated expression of tumour-derived angiogenic factors. The identification of molecular 'addresses' on the surface of tumour vasculature has significantly contributed to the selection of targets, which have been used for delivering therapeutic and imaging agents in cancer. Cytotoxic drug, pro-apoptotic peptides, protease inhibitors, and gene therapy vectors have been successfully linked to peptides and delivered to tumour sites with an improved experimental therapy. Different diagnostic and therapeutic compounds can be efficiently targeted to specific receptors on vascular endothelial cells; the development of ligand-directed vector tools may promote systemic targeted gene delivery. Here, we review the very recent advances in the identification of peptide ligands and their corresponding tissue-specific endothelial receptors through the phage display technology with emphasis on ligand-directed delivery of therapeutic agents and targeted gene therapy.

  • Cathepsin D-Bax death pathway in oxidative stressed neuroblastoma cells.
    Publication Date: 01/05/2007, on Free radical biology & medicine
    by Castino R, Bellio N, Nicotra G, Follo C, Trincheri NF, Isidoro C
    DOI: 10.1016/j.freeradbiomed.2006.12.030

    Hydrogen peroxide, the major oxidoradical species in the central nervous system, has been involved in neuronal cell death and associated neurodegenerative diseases. In this study, we have investigated the involvement of the lysosomal pathway in the cytotoxic mechanism of hydrogen peroxide in human neuroblastoma cells. Alteration of lysosomal and mitochondrial membrane integrity was shown to be an early event in the lethal cascade triggered by oxidative stress. Desferrioxamine (DFO), an iron chelator that abolishes the formation of reactive oxygen species within lysosomes, prevented lysosome leakage, mitochondrial permeabilization and caspase-dependent apoptosis in hydrogen peroxide-treated cells. Inhibition of cathepsin D, not of cathepsin B, as well as small-interference RNA-mediated silencing of the cathepsin D gene prevented hydrogen peroxide-induced injury of mitochondria, caspase activation, and TUNEL-positive cell death. Cathepsin D activity was shown indispensable for translocation of Bax onto mitochondrial membrane associated with oxidative stress. DFO abolished both the cytosolic relocation of Cathepsin D and the mitochondrial relocation of Bax in hydrogen peroxide-treated cells. siRNA-mediated down-regulation of Bax expression protected the cells from oxidoradical injury. The present study identifies the lysosome as the primary target and the axis cathepsin D-Bax as the effective pathway of hydrogen peroxide lethal activity in neuroblastoma cells.