Latest PUBLICATIONS

  • Mitochondrial chaperone Trap1 and the calcium binding protein Sorcin interact and protect cells against apoptosis induced by antiblastic agents.
    Publication Date: 15/08/2010, on Cancer research
    by Landriscina M, Laudiero G, Maddalena F, Amoroso MR, Piscazzi A, Cozzolino F, Monti M, Garbi C, Fersini A, Pucci P, Esposito F
    DOI: 10.1158/0008-5472.CAN-10-1256

    TRAP1, a mitochondrial chaperone (Hsp75) with antioxidant and antiapoptotic functions, is involved in multidrug resistance in human colorectal carcinoma cells. Through a proteomic analysis of TRAP1 coimmunoprecipitation complexes, the Ca(2+)-binding protein Sorcin was identified as a new TRAP1 interactor. This result prompted us to investigate the presence and role of Sorcin in mitochondria from human colon carcinoma cells. Using fluorescence microscopy and Western blot analysis of purified mitochondria and submitochondrial fractions, we showed the mitochondrial localization of an isoform of Sorcin with an electrophoretic motility lower than 20 kDa that specifically interacts with TRAP1. Furthermore, the effects of overexpressing or downregulating Sorcin and/or TRAP1 allowed us to demonstrate a reciprocal regulation between these two proteins and to show that their interaction is required for Sorcin mitochondrial localization and TRAP1 stability. Indeed, the depletion of TRAP1 by short hairpin RNA in colorectal carcinoma cells lowered Sorcin levels in mitochondria, whereas the depletion of Sorcin by small interfering RNA increased TRAP1 degradation. We also report several lines of evidence suggesting that intramitochondrial Sorcin plays a role in TRAP1 cytoprotection. Finally, preliminary evidence that TRAP1 and Sorcin are both implicated in multidrug resistance and are coupregulated in human colorectal carcinomas is provided. These novel findings highlight a new role for Sorcin, suggesting that some of its previously reported cytoprotective functions may be explained by involvement in mitochondrial metabolism through the TRAP1 pathway.

  • Transcription factor KLF7 regulates differentiation of neuroectodermal and mesodermal cell lineages.
    Publication Date: 15/08/2010, on Experimental cell research
    by Caiazzo M, Colucci-D'Amato L, Esposito MT, Parisi S, Stifani S, Ramirez F, di Porzio U
    DOI: 10.1016/j.yexcr.2010.05.021

    Previous gene targeting studies in mice have implicated the nuclear protein Krüppel-like factor 7 (KLF7) in nervous system development while cell culture assays have documented its involvement in cell cycle regulation. By employing short hairpin RNA (shRNA)-mediated gene silencing, here we demonstrate that murine Klf7 gene expression is required for in vitro differentiation of neuroectodermal and mesodermal cells. Specifically, we show a correlation of Klf7 silencing with down-regulation of the neuronal marker microtubule-associated protein 2 (Map2) and the nerve growth factor (NGF) tyrosine kinase receptor A (TrkA) using the PC12 neuronal cell line. Similarly, KLF7 inactivation in Klf7-null mice decreases the expression of the neurogenic marker brain lipid-binding protein/fatty acid-binding protein 7 (BLBP/FABP7) in neural stem cells (NSCs). We also report that Klf7 silencing is detrimental to neuronal and cardiomyocytic differentiation of embryonic stem cells (ESCs), in addition to altering the adipogenic and osteogenic potential of mouse embryonic fibroblasts (MEFs). Finally, our results suggest that genes that are key for self-renewal of undifferentiated ESCs repress Klf7 expression in ESCs. Together with previous findings, these results provide evidence that KLF7 has a broad spectrum of regulatory functions, which reflect the discrete cellular and molecular contexts in which this transcription factor operates.

  • Effects of a lipid environment on the fibrillogenic pathway of the N-terminal polypeptide of human apolipoprotein A-I, responsible for in vivo amyloid fibril formation.
    Publication Date: 01/08/2010, on European biophysics journal : EBJ
    by Monti DM, Guglielmi F, Monti M, Cozzolino F, Torrassa S, Relini A, Pucci P, Arciello A, Piccoli R
    DOI: 10.1007/s00249-010-0582-2

    In amyloidosis associated with apolipoprotein A-I (ApoA-I), heart amyloid deposits are mainly constituted by the 93-residue ApoA-I N-terminal region. A recombinant form of the amyloidogenic polypeptide, named [1-93]ApoA-I, shares conformational properties and aggregation propensity with its natural counterpart. The polypeptide, predominantly in a random coil state at pH 8.0, following acidification to pH 4.0 adopts a helical/molten globule transient state, which leads to formation of aggregates. Here we provide evidence that fibrillogenesis occurs also in physiologic-like conditions. At pH 6.4, [1-93]ApoA-I was found to assume predominantly an alpha-helical state, which undergoes aggregation at 37 degrees C over time at a lower rate than at pH 4.0. After 7 days at pH 6.4, protofibrils were observed by atomic force microscopy (AFM). Using a multidisciplinary approach, including circular dichroism (CD), fluorescence, electrophoretic, and AFM analyses, we investigated the effects of a lipid environment on the conformational state and aggregation propensity of [1-93]ApoA-I. Following addition of the lipid-mimicking detergent Triton X-100, the polypeptide was found to be in a helical state at both pH 8.0 and 6.4, with no conformational transition occurring upon acidification. These helical conformers are stable and do not generate aggregated species, as observed by AFM after 21 days. Similarly, analyses of the effects of cholesterol demonstrated that this natural ApoA-I ligand induces formation of alpha-helix at physiological concentrations at both pH 8.0 and 6.4. Zwitterionic, positively charged, and negatively charged liposomes were found to affect [1-93]ApoA-I conformation, inducing helical species. Our data support the idea that lipids play a key role in [1-93]ApoA-I aggregation in vivo.

  • Recognition and mental manipulation of body parts dissociate in locked-in syndrome.
    Publication Date: 01/08/2010, on Brain and cognition
    by Conson M, Pistoia F, Sarà M, Grossi D, Trojano L
    DOI: 10.1016/j.bandc.2010.05.001

    Several lines of evidence demonstrate that the motor system is involved in motor simulation of actions, but some uncertainty exists about the consequences of lesions of descending motor pathways on mental imagery tasks. Moreover, recent findings suggest that the motor system could also have a role in recognition of body parts. To address these issues in the present study we assessed patients with a complete damage of descending motor pathways (locked-in syndrome, LIS) on the hand laterality task, requiring subjects to decide whether a hand stimulus in a given spatial orientation represents a left or a right hand. LIS patients were less accurate than healthy controls in judging hand laterality; more importantly, LIS patients' performance was modulated by spatial orientation of hand stimuli whereas it was not affected by biomechanical constraints. These findings demonstrate a dissociation between spared hand recognition and impaired access to action simulation processes in LIS patients.

  • Hereditary cerebral hemorrhage with amyloidosis associated with the E693K mutation of APP.
    Publication Date: 01/08/2010, on Archives of neurology
    by Bugiani O, Giaccone G, Rossi G, Mangieri M, Capobianco R, Morbin M, Mazzoleni G, Cupidi C, Marcon G, Giovagnoli A, Bizzi A, Di Fede G, Puoti G, Carella F, Salmaggi A, Romorini A, Patruno GM, Magoni M, Padovani A, Tagliavini F
    DOI: 10.1001/archneurol.2010.178

    To report the clinical, genetic, neuroimaging, and neuropathologic studies of patients with the hereditary cerebral hemorrhage with amyloidosis linked to the APP E693K mutation.

  • Variably protease-sensitive prionopathy: a new sporadic disease of the prion protein.
    Publication Date: 01/08/2010, on Annals of neurology
    by Zou WQ, Puoti G, Xiao X, Yuan J, Qing L, Cali I, Shimoji M, Langeveld JP, Castellani R, Notari S, Crain B, Schmidt RE, Geschwind M, Dearmond SJ, Cairns NJ, Dickson D, Honig L, Torres JM, Mastrianni J, Capellari S, Giaccone G, Belay ED, Schonberger LB, Cohen M, Perry G, Kong Q, Parchi P, Tagliavini F, Gambetti P
    DOI: 10.1002/ana.22094

    The objective of the study is to report 2 new genotypic forms of protease-sensitive prionopathy (PSPr), a novel prion disease described in 2008, in 11 subjects all homozygous for valine at codon 129 of the prion protein (PrP) gene (129VV). The 2 new PSPr forms affect individuals who are either homozygous for methionine (129MM) or heterozygous for methionine/valine (129MV).

  • Late recovery after traumatic, anoxic, or hemorrhagic long-lasting vegetative state.
    Publication Date: 20/07/2010, on Neurology
    by Estraneo A, Moretta P, Loreto V, Lanzillo B, Santoro L, Trojano L
    DOI: 10.1212/WNL.0b013e3181e8e8cc

    Late recovery of awareness in vegetative state (VS) is considered as an exceptional outcome, and has been reported prevalently after traumatic brain injury (TBI). The present prospective study aimed to verify frequency of late recovery (later than 1 year postonset in TBI and 3 months postonset in patients without TBI) of responsiveness and consciousness in traumatic and nontraumatic long-lasting (more than 6 months after onset) VS.

  • Terpioside B, a difucosyl GSL from the marine sponge Terpios sp. is a potent inhibitor of NO release.
    Publication Date: 15/07/2010, on Bioorganic & medicinal chemistry
    by Costantino V, Fattorusso E, Mangoni A, Teta R, Panza E, Ianaro A
    DOI: 10.1016/j.bmc.2010.05.048

    Terpioside B (2a), a unique glycolipid containing two fucose residues in the furanose form in its pentasaccharide chain, was isolated from the marine sponge Terpios sp. Its complete stereostructure was solved by interpretation of mass spectrometric and NMR data along with CD and GG-MS analyses of its degradation products. Terpioside B is a potent inhibitor against LPS-induced NO release, and is considerably more active than simpler glycosphingolipids such as terpioside A and monoglucosylceramide.

  • Controlled delivery of the heparan sulfate/FGF-2 complex by a polyelectrolyte scaffold promotes maximal hMSC proliferation and differentiation.
    Publication Date: 01/07/2010, on Journal of cellular biochemistry
    by Calarco A, Petillo O, Bosetti M, Torpedine A, Cannas M, Perrone L, Galderisi U, Melone MA, Peluso G
    DOI: 10.1002/jcb.22602

    Growth factors and other regulatory molecules are required to direct differentiation of bone marrow-derived human mesenchymal stem cells (hMSC) along specific lineages. However, the therapeutic use of growth factors is limited by their susceptibility to degradation, and the need to maintain prolonged local release of growth factor at levels sufficient to stimulate hMSC. The aim of this study was to investigate whether a device containing heparan sulfate (HS), which is a co-factor in growth factor-mediated cell proliferation and differentiation, could potentiate and prolong the delivery of fibroblast growth factor-2 (FGF-2) and thus enhance hMSC stimulation. To this aim, we synthesized cationic polyelectrolyte polymers covalently and non-covalently anchored to HS and evaluated their effect on hMSC proliferation. Polymers non-covalently bound to HS resulted in the release of an HS/FGF-2 complex rather than FGF-2 alone. The release of this complex significantly restored hMSC proliferation, which was abolished in serum-free medium and only partially restored by the release of FGF-2 alone as occurred with polymer covalently bound to HS. We also demonstrate that exposure to HS/FGF-2 during early growth but not during post-confluence is essential for hMSC differentiation down the fibroblast lineage, which suggests that both factors are required to establish the correct stem cell commitment that is necessary to support subsequent differentiation. In conclusion, the delivery platform described here is a step towards the development of a new class of biomaterial that enables the prolonged, non-covalent binding and controlled delivery of growth factors and cofactors without altering their potency.

  • Autophagy-active beclin-1 correlates with favourable clinical outcome in non-Hodgkin lymphomas.
    Publication Date: 01/07/2010, on Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc
    by Nicotra G, Mercalli F, Peracchio C, Castino R, Follo C, Valente G, Isidoro C
    DOI: 10.1038/modpathol.2010.80

    The expression of beclin-1, an oncosuppressor monoallelically deleted in >60% epithelial cancers, has been shown to be developmentally regulated in T and B lymphocytes. By interacting with either bcl-2 or class III phosphatidyl-inositol-3-phosphate kinase, beclin-1 regulates apoptosis and autophagy, two processes crucial for lymphatic tissue homeostasis. We analyzed the potential link between beclin-1-mediated autophagy and the malignant behaviour of lymphomas. The tissue expression of beclin-1 was analyzed in a large series of non-Hodgkin lymphomas and correlated with patient's clinical outcome. By immunofluorescence, beclin-1 staining showed faintly detectable and diffusely distributed in the cytoplasm (regarded as negative) or confined to the perinuclear region as large and brilliant puncta suggestive of macro-aggregate reactivity (regarded as positive). The positive expression of beclin-1 well correlated with the presence of LC3-positive autophagic vacuoles and was inversely correlated with the expression of bcl-2. Non-Hodgkin lymphomas in which > or =20% of tumour cells expressed high level of beclin-1 aggregates were associated with a complete (57%) or partial (35%) remission. The 5-year overall survival probability, calculated by the Kaplan-Meier method, was 92% and 42% in beclin-1-expressing non-Hodgkin lymphomas with > or =20% and <20% positive cells, respectively (log-rank test, P<0.000.1). In Cox multivariate analysis, the level of beclin-1 expression, adjusted for patient's age and pathologic stage, revealed to be significantly correlated with patient's survival (P<0.0001). This is the first demonstration of the involvement of beclin-1 and autophagy in the clinical behaviour of non-Hodgkin lymphomas. The present data are compatible with the hypothesis that non-Hodgkin lymphomas with upregulated autophagy are more responsive to chemotherapy and indicate that beclin-1 could be a valuable independent prognostic factor in this heterogeneous group of tumours.

  • Common variants in the regulative regions of GRIA1 and GRIA3 receptor genes are associated with migraine susceptibility.
    Publication Date: 25/06/2010, on BMC medical genetics
    by Formicola D, Aloia A, Sampaolo S, Farina O, Diodato D, Griffiths LR, Gianfrancesco F, Di Iorio G, Esposito T
    DOI: 10.1186/1471-2350-11-103

    Glutamate is the principal excitatory neurotransmitter in the central nervous system which acts by the activation of either ionotropic (AMPA, NMDA and kainate receptors) or G-protein coupled metabotropic receptors. Glutamate is widely accepted to play a major role in the path physiology of migraine as implicated by data from animal and human studies. Genes involved in synthesis, metabolism and regulation of both glutamate and its receptors could be, therefore, considered as potential candidates for causing/predisposing to migraine when mutated.

  • Impaired conscious recognition of negative facial expressions in patients with locked-in syndrome.
    Publication Date: 09/06/2010, on The Journal of neuroscience : the official journal of the Society for Neuroscience
    by Pistoia F, Conson M, Trojano L, Grossi D, Ponari M, Colonnese C, Pistoia ML, Carducci F, Sarà M
    DOI: 10.1523/JNEUROSCI.6300-09.2010

    The involvement of facial mimicry in different aspects of human emotional processing is widely debated. However, little is known about relationships between voluntary activation of facial musculature and conscious recognition of facial expressions. To address this issue, we assessed severely motor-disabled patients with complete paralysis of voluntary facial movements due to lesions of the ventral pons [locked-in syndrome (LIS)]. Patients were required to recognize others' facial expressions and to rate their own emotional responses to presentation of affective scenes. LIS patients were selectively impaired in recognition of negative facial expressions, thus demonstrating that the voluntary activation of mimicry represents a high-level simulation mechanism crucially involved in explicit attribution of emotions.

  • The myotonic dystrophy type 2 (DM2) gene product zinc finger protein 9 (ZNF9) is associated with sarcomeres and normally localized in DM2 patients' muscles.
    Publication Date: 01/06/2010, on Neuropathology and applied neurobiology
    by Massa R, Panico MB, Caldarola S, Fusco FR, Sabatelli P, Terracciano C, Botta A, Novelli G, Bernardi G, Loreni F
    DOI: 10.1111/j.1365-2990.2010.01068.x

    Myotonic dystrophy type 2 (DM2) is caused by a [CCTG]n intronic expansion in the zinc finger protein 9 (ZNF9) gene. As for DM1, sharing with DM2 a similar phenotype, the pathogenic mutation involves a transcribed but untranslated genomic region, suggesting that RNA toxicity may have a role in the pathogenesis of these multisystem disorders by interfering with common cellular mechanisms. However, haploinsufficiency has been described in DM1 and DM2 animal models, and might contribute to pathogenesis. The aim of the present work was therefore to assess ZNF9 protein expression in rat tissues and in human muscle, and ZNF9 subcellular distribution in normal and DM2 human muscles.

  • Selective Binding of Distamycin A Derivative to G-Quadruplex Structure [d(TGGGGT)](4).
    Publication Date: 30/05/2010, on Journal of nucleic acids
    by Pagano B, Fotticchia I, De Tito S, Mattia CA, Mayol L, Novellino E, Randazzo A, Giancola C
    DOI: 10.4061/2010/247137

    Guanine-rich nucleic acid sequences can adopt G-quadruplex structures stabilized by layers of four Hoogsteen-paired guanine residues. Quadruplex-prone sequences are found in many regions of human genome and in the telomeres of all eukaryotic organisms. Since small molecules that target G-quadruplexes have been found to be effective telomerase inhibitors, the identification of new specific ligands for G-quadruplexes is emerging as a promising approach to develop new anticancer drugs. Distamycin A is known to bind to AT-rich sequences of duplex DNA, but it has recently been shown to interact also with G-quadruplexes. Here, isothermal titration calorimetry (ITC) and NMR techniques have been employed to characterize the interaction between a dicationic derivative of distamycin A (compound 1) and the [d(TGGGGT)](4) quadruplex. Additionally, to compare the binding behaviour of netropsin and compound 1 to the same target, a calometric study of the interaction between netropsin and [d(TGGGGT)](4) has been performed. Experiments show that netropsin and compound 1 are able to bind to [d(TGGGGT)](4) with good affinity and comparable thermodynamic profiles. In both cases the interactions are entropically driven processes with a small favourable enthalpic contribution. Interestingly, the structural modifications of compound 1 decrease the affinity of the ligand toward the duplex, enhancing the selectivity.

  • Structural and conformational requisites in DNA quadruplex groove binding: another piece to the puzzle.
    Publication Date: 12/05/2010, on Journal of the American Chemical Society
    by Cosconati S, Marinelli L, Trotta R, Virno A, De Tito S, Romagnoli R, Pagano B, Limongelli V, Giancola C, Baraldi PG, Mayol L, Novellino E, Randazzo A
    DOI: 10.1021/ja1003872

    The study of DNA G-quadruplex stabilizers has enjoyed a great momentum in the late years due to their application as anticancer agents. The recognition of the grooves of these structural motifs is expected to result in a higher degree of selectivity over other DNA structures. Therefore, to achieve an enhanced knowledge on the structural and conformational requisites for quadruplex groove recognition, distamycin A, the only compound for which a pure groove binding has been proven, has been chemically modified. Surprisingly, structural and thermodynamic studies revealed that the absence of Coulombic interactions results in an unprecedented binding position in which both the groove and the 3' end of the DNA are occupied. This further contribution adds another piece to the so far elusive puzzle of the recognition between ligands and DNA quadruplexes and will serve as a platform for a rational design of new groove binders.