Latest PUBLICATIONS

  • Spastic paraplegia with thin corpus callosum: description of 20 new families, refinement of the SPG11 locus, candidate gene analysis and evidence of genetic heterogeneity.
    Publication Date: 01/07/2006, on Neurogenetics
    by Stevanin G, Montagna G, Azzedine H, Valente EM, Durr A, Scarano V, Bouslam N, Cassandrini D, Denora PS, Criscuolo C, Belarbi S, Orlacchio A, Jonveaux P, Silvestri G, Hernandez AM, De Michele G, Tazir M, Mariotti C, Brockmann K, Malandrini A, van der Knapp MS, Neri M, Tonekaboni H, Melone MA, Tessa A, Dotti MT, Tosetti M, Pauri F, Federico A, Casali C, Cruz VT, Loureiro JL, Zara F, Forlani S, Bertini E, Coutinho P, Filla A, Brice A, Santorelli FM
    DOI: 10.1007/s10048-006-0044-2

    We studied 20 Mediterranean families (40 patients) with autosomal recessive hereditary spastic paraplegia and thin corpus callosum (ARHSP-TCC, MIM 604360) to characterize their clinical and genetic features. In six families (17 patients) of Algerian Italian, Moroccan, and Portuguese ancestry, we found data consistent with linkage to the SPG11 locus on chromosome 15q13-15, whereas, in four families (nine patients of Italian, French, and Portuguese ancestry) linkage to the SPG11 locus could firmly be excluded, reinforcing the notion that ARHSP-TCC is genetically heterogeneous. Patients from linked and unlinked families could not be distinguished on the basis of clinical features alone. In SPG11-linked kindred, haplotype reconstruction allowed significant refinement to 6 cM, of the minimal chromosomal interval, but analysis of two genes (MAP1A and SEMA6D) in this region did not identify causative mutations. Our findings suggest that ARHSP-TCC is the most frequent form of ARHSP in Mediterranean countries and that it is particularly frequent in Italy.

  • Exploring the mechanism of formation of native-like and precursor amyloid oligomers for the native acylphosphatase from Sulfolobus solfataricus.
    Publication Date: 01/06/2006, on Structure (London, England : 1993)
    by Plakoutsi G, Bemporad F, Monti M, Pagnozzi D, Pucci P, Chiti F
    DOI: 10.1016/j.str.2006.03.014

    Over 40 human diseases are associated with the formation of well-defined proteinaceous fibrillar aggregates. Since the oligomers precursors to the fibrils are increasingly recognized to be the causative agents of such diseases, it is important to elucidate the mechanism of formation of these early species. The acylphosphatase from Sulfolobus solfataricus is an ideal system as it was found to form, under conditions in which it is initially native, two types of prefibrillar aggregates: (1) initial enzymatically active aggregates and (2) oligomers with characteristics reminiscent of amyloid protofibrils, with the latter originating from the structural reorganization of the initial assemblies. By studying a number of protein variants with a variety of biophysical techniques, we have identified the regions of the sequence and the driving forces that promote the first aggregation phase and show that the second phase consists in a cooperative conversion involving the entire globular fold.

  • Indole-3-acetic acid improves Escherichia coli's defences to stress.
    Publication Date: 01/06/2006, on Archives of microbiology
    by Bianco C, Imperlini E, Calogero R, Senatore B, Amoresano A, Carpentieri A, Pucci P, Defez R
    DOI: 10.1007/s00203-006-0103-y

    Indole-3-acetic acid (IAA) is a ubiquitous molecule playing regulatory roles in many living organisms. To elucidate the physiological changes induced by IAA treatment, we used Escherichia coli K-12 as a model system. By microarray analysis we found that 16 genes showed an altered expression level in IAA-treated cells. One-third of these genes encode cell envelope components, or proteins involved in bacterial adaptation to unfavourable environmental conditions. We thus investigated the effect of IAA treatment on some of the structural components of the envelope that may be involved in cellular response to stresses. This showed that IAA-treated cells had increased the production of trehalose, lipopolysaccharide (LPS), exopolysaccharide (EPS) and biofilm. We demonstrated further that IAA triggers an increased tolerance to several stress conditions (heat and cold shock, UV-irradiation, osmotic and acid shock and oxidative stress) and different toxic compounds (antibiotics, detergents and dyes) and this correlates with higher levels of the heat shock protein DnaK. We suggest that IAA triggers an increased level of alert and protection against external adverse conditions by coordinately enhancing different cellular defence systems.

  • Predictors of tumor shrinkage after primary therapy with somatostatin analogs in acromegaly: a prospective study in 99 patients.
    Publication Date: 01/06/2006, on The Journal of clinical endocrinology and metabolism
    by Colao A, Pivonello R, Auriemma RS, Briganti F, Galdiero M, Tortora F, Caranci F, Cirillo S, Lombardi G
    DOI: 10.1210/jc.2005-2110

    Primary treatment with depot octreotide and lanreotide induces tumor shrinkage in newly diagnosed patients with acromegaly.

  • PI3K-dependent lysosome exocytosis in nitric oxide-preconditioned hepatocytes.
    Publication Date: 15/05/2006, on Free radical biology & medicine
    by Carini R, Trincheri NF, Alchera E, De Cesaris MG, Castino R, Splendore R, Albano E, Isidoro C
    DOI: 10.1016/j.freeradbiomed.2006.01.013

    We investigated the signal mediators and the cellular events involved in the nitric oxide (NO)-induced hepatocyte resistance to oxygen deprivation in isolated hepatocytes treated with the NO donor (Z)-1-(N-methyl-N-[6-(N-methylammoniohexyl)amino])diazen-1-ium-1,2-diolate (NOC-9). NOC-9 greatly induced PI3K activation, as tested by phosphorylation of PKB/Akt. This effect was prevented by either 1H-(1,2,4)-oxadiazolo-(4,3)-quinoxalin-1-one, an inhibitor of the soluble guanylate cyclase (sGC), or KT5823, an inhibitor of cGMP-dependent kinase (cGK), as well as by farnesyl protein transferase inhibitor, which blocks the function of Ras GTPase. Bafilomycin A, an inhibitor of the lysosome-type vacuolar H+-ATPase, cytochalasin D, which disrupts the cytoskeleton-dependent organelle traffic, and wortmannin, which inhibits the PI3K-dependent traffic of lysosomes, all abolished the NOC-9-induced hepatocyte protection. The treatment with NOC-9 was associated with the PI3K-dependent peripheral translocation and fusion with the plasma membrane of lysosomes and the appearance at the cell surface of the vacuolar H+-ATPase. Inhibition of sGC, cGK, and Ras, as well as the inhibition of PI3K by wortmannin, prevented the exocytosis of lysosomes and concomitantly abolished the protective effect of NOC-9 on hypoxia-induced pHi and [Na+]i alterations and cell death. These data indicate that NO increases hepatocyte resistance to hypoxic injury by activating a pathway involving Ras, sGC, and cGK that determines PI3K-dependent exocytosis of lysosomes.

  • Relative effects of phenolic constituents from Yucca schidigera Roezl. bark on Kaposi's sarcoma cell proliferation, migration, and PAF synthesis.
    Publication Date: 14/05/2006, on Biochemical pharmacology
    by Balestrieri C, Felice F, Piacente S, Pizza C, Montoro P, Oleszek W, Visciano V, Balestrieri ML
    DOI: 10.1016/j.bcp.2006.01.021

    Yuccaols (A, B, C) are phenolic constituents isolated from Yucca schidigera bark characterized by unusual spirostructures made up of a C15 unit and a stilbenic portion closely related to resveratrol. These novel compounds are of particular interest for their antioxidant and anti-inflammatory properties. However, their effects on cell proliferation, migration, and platelet-activating factor (PAF) biosynthesis remain unknown. PAF, a potent mediator of inflammation, is known to promote angiogenesis and in vitro migration of endothelial cells and Kaposi's sarcoma (KS) cells. The objective of our study was to determine the effect of Yuccaols and resveratrol on the vascular endothelial growth factor (VEGF)-induced proliferation, migration, and PAF biosynthesis in KS cells. The results indicated that Yuccaols (25 microM) were more effective than resveratrol (25 microM) in inhibiting the VEGF-induced KS cell proliferation. Western blot analysis revealed that Yuccaols reduced the VEGF-induced phosphorylation of p38 and p42/44, thus indicating a possible interference with the mechanism underlying the VEGF-stimulated cell proliferation. Furthermore, Yuccaols completely inhibited the VEGF-stimulated PAF biosynthesis catalyzed by the acetyl-CoA:lyso-PAF acetyltransferase and enhanced its degradation through the PAF-dependent CoA-independent transacetylase (250% of control). In addition, Yuccaol C abrogated the PAF-induced cell motility whereas Yuccaol A and Yuccaol B reduced the cell migration from 7.6 microm/h to 6.1 microm/h and 5.6 microm/h, respectively. These results indicate that the anti-inflammatory properties attributed to Yucca schidigera can be ascribed to both resveratrol and Yuccaols and provide the first evidences of the anti-tumor and anti-invasive properties of these novel phenolic compounds.

  • Lysophospholipid transacetylase in the regulation of PAF levels in human monocytes and macrophages.
    Publication Date: 01/05/2006, on FASEB journal : official publication of the Federation of American Societies for Experimental Biology
    by Servillo L, Balestrieri C, Giovane A, Pari P, Palma D, Giannattasio G, Triggiani M, Balestrieri ML
    DOI: 10.1096/fj.05-5059fje

    The transacetylase (TA), reported to be identical to platelet-activating factor (PAF) acetylhydrolase (II), is a multifunctional enzyme with three catalytic activities: lysophospholipid transacetylase (TA(L)), sphingosine transacetylase (TA(S)), and acetylhydrolase (AH). We report that TA(L) activity participates in the control of PAF levels in monocytes and macrophages and that its regulation differs in these two types of cells. In monocytes, LPS or granulocyte-macrophage colony-stimulating factor (GM-CSF) specifically increased the TA(L) activity. Western blot analysis and enzyme assays on immunoprecipitates revealed that the increased activity can be ascribed to PAF-AH (II) and that both translocation from cytosol to membranes and p38/ERKs-mediated phosphorylation regulate the enzyme activation. Instead, in macrophages differentiated in vitro from monocytes by incubation with FCS, an increase of both TA(L) and AH activities was observed. Moreover, activation of ERKs and p38 MAP kinase was not required for the up-regulation of PAF-AH (II) in differentiated macrophages. The differences observed in macrophages as compared to monocytes can be explained by 1) p38/ERKs-independent phosphorylation of PAF-AH (II) and 2) appearance of plasma PAF-AH in the course of macrophage differentiation.

  • Prognostic significance of microvessel density and vascular endothelial growth factor expression in sinonasal carcinomas.
    Publication Date: 01/04/2006, on Human pathology
    by Valente G, Mamo C, Bena A, Prudente E, Cavaliere C, Kerim S, Nicotra G, Comino A, Palestro G, Isidoro C, Beatrice F
    DOI: 10.1016/j.humpath.2005.11.021

    The prognostic significance of microvessel density and proliferative activity of the neoplastic cells, evaluated respectively by CD31 and Ki-67 positivity, and immunohistochemical expression of vascular endothelial growth factor (VEGF) was retrospectively investigated in 105 cases of sinonasal carcinoma (80 surgical specimens and 25 biopsies). The most represented histologic types were intestinal-type adenocarcinoma found in 36 patients (34.3%), squamous cell carcinoma (SCC) in 34 (32.4%), mucinous adenocarcinoma (mainly made up of signet-ring cell patterns) in 15 (14.3%), and adenoid cystic carcinoma in 7 (6.7%). Microvessel density values (in vessels per square millimeter), VEGF, and Ki-67 were not dependent on histologic type but were rather correlated to the histologic grading in SCC. Clinical data were available for 92 (87.6%) of 105 patients, with minimum follow-up of 48 months. Most of the patients (81.5%) were at an advanced stage (T3-T4) at diagnosis. The values of all markers were correlated to tumor stage (P = .03). Multivariate analysis showed that both microvessel density and proliferative activity of the neoplastic cells were independent prognostic parameters (mortality hazard ratio, 1.33 and 1.60, respectively). Although VEGF expression was not correlated to prognosis on the whole series (P = .06), it was a powerful prognostic marker when the analysis was restricted to the group of SCCs (hazard ratio, 3.02; 90% confidence interval, 1.58-5.80). These results show that tumor neoangiogenesis, expressed by microvessel density, together with proliferative activity, is a pathologic marker with a strong prognostic impact in sinonasal carcinomas. Therefore, it may be a useful tool in this field so as to carry out therapeutic protocol planning, which may be further enhanced by the adoption of the more recent antiangiogenic molecules.

  • GPI-anchored proteins are directly targeted to the apical surface in fully polarized MDCK cells.
    Publication Date: 27/03/2006, on The Journal of cell biology
    by Paladino S, Pocard T, Catino MA, Zurzolo C
    DOI: 10.1083/jcb.200507116

    The polarity of epithelial cells is dependent on their ability to target proteins and lipids in a directional fashion. The trans-Golgi network, the endosomal compartment, and the plasma membrane act as sorting stations for proteins and lipids. The site of intracellular sorting and pathways used for the apical delivery of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) are largely unclear. Using biochemical assays and confocal and video microscopy in living cells, we show that newly synthesized GPI-APs are directly delivered to the apical surface of fully polarized Madin-Darby canine kidney cells. Impairment of basolateral membrane fusion by treatment with tannic acid does not affect the direct apical delivery of GPI-APs, but it does affect the organization of tight junctions and the integrity of the monolayer. Our data clearly demonstrate that GPI-APs are directly sorted to the apical surface without passing through the basolateral membrane. They also reinforce the hypothesis that apical sorting of GPI-APs occurs intracellularly before arrival at the plasma membrane.

  • Impairment of spermatogenesis and enhancement of testicular germ cell apoptosis induced by exogenous all-trans-retinoic acid in adult lizard Podarcis sicula.
    Publication Date: 01/03/2006, on Journal of experimental zoology. Part A, Comparative experimental biology
    by Comitato R, Esposito T, Cerbo G, Angelini F, Varriale B, Cardone A
    DOI: 10.1002/jez.a.264

    In mammals, retinoic acid is involved in the regulation of testicular function by interaction with two families of nuclear receptors, retinoic acid receptor (RAR) and retinoid X receptor (RXR). Among RAR isoforms, the testicular cells of the lizard were found to express only RARalpha (3.7 kb) and RARbeta (3.4 kb) mRNAs, as reported here. In this study, the effects of exogenous all-trans-retinoic acid (atRA) on spermatogenesis of a non-mammalian seasonal reproducer were investigated. Daily intraperitoneal injections of atRA or atRA plus testosterone (atRA+T) were given for 2 weeks to adult males of the lizard Podarcis sicula. In animals treated with atRA, the seminiferous tubules were markedly reduced in cross-area. The seminiferous epithelium collapse was responsible for a sensible reduction in the number of germ cells and disruption in normal epithelial organization. In comparison, in atRA+T-treated lizards the loss of germinal cells was significantly less. The loss of germ cells observed in both experimental groups results from an induction of apoptotic process, as revealed by TUNEL analysis. Although low in number, apoptotic germ cells were also observed in the control groups (saline- and T-treated lizard), where the main germ cells undergoing apoptosis are primary spermatocytes (most frequently) and some spermatogonia. In conclusion, it is shown here that retinoic acid has deleterious effects on lizard spermatogenesis, causing a severe depletion of seminiferous epithelium, probably via induction of apoptotic processes. These effects are not completely inhibited by simultaneous administration of testosterone, although this hormone, once injected, is able to stimulate spermatogenesis and protect germinal cells from apoptotic cell death.

  • cFLIP expression correlates with tumour progression and patient outcome in non-Hodgkin lymphomas of low grade of malignancy.
    Publication Date: 01/03/2006, on British journal of haematology
    by Valente G, Manfroi F, Peracchio C, Nicotra G, Castino R, Nicosia G, Kerim S, Isidoro C
    DOI: 10.1111/j.1365-2141.2005.05898.x

    The present study investigated whether the expression of cellular Fas-associated death domain-like interleukin-1beta-converting enzyme (FLICE) inhibitory protein (cFLIP) conveys prognostic information in non-Hodgkin lymphomas (NHLs). cFLIP expression was quantified by immunohistochemistry and immunofluorescence in biopsy specimens from 86 NHL patients for whom clinical information was available. NHL malignancy was graded as high/intermediate or low according to the World Health Organization Classification of Lymphoid Neoplasms. cFLIP was positive in 23 of 45 high-/intermediate-grade NHLs and in 25 of 41 low-grade NHLs. Negative expression of cFLIP was associated with the presence of apoptotic cells in the tumour mass, regardless of the histotype and of the malignancy grade. In NHLs positive for cFLIP, 11 of 23 (48%) high-/intermediate-grade cases and 18 of 25 (72%) low-grade cases showed a bad outcome. In NHLs negative for cFLIP, only four of 22 (18%) high-/intermediate-grade patients and 12 of 16 (75%) low-grade patients achieved complete remission. All these correlations were statistically significant. The correlation of cFLIP expression with clinical outcome was independent of therapy, whether or not it included anti-CD20 antibody (Rituximab). The present findings strongly indicate that cFLIP is a reliable predictor of tumour progression and clinical prognosis in NHLs of low grade of malignancy.

  • Overexpression of ErbB2 and ErbB3 receptors in Schwann cells of patients with Charcot-Marie-tooth disease type 1A.
    Publication Date: 01/03/2006, on Muscle & nerve
    by Massa R, Palumbo C, Cavallaro T, Panico MB, Bei R, Terracciano C, Rizzuto N, Bernardi G, Modesti A
    DOI: 10.1002/mus.20460

    Axon-derived neuregulins (NRGs) are a family of growth factors whose binding to ErbB tyrosine kinase receptors promotes the maturation, proliferation and survival of Schwann cells (SCs). Correct NRG/ErbB signaling is essential for the homeostasis of axonal-glial complexes and seems to play a role in peripheral nerve repair. The potential involvement of ErbB receptors in human peripheral neuropathies has not been clarified. Therefore, we assessed the immunoreactivity for EGFR (ErbB1), ErbB2, and ErbB3 in nerve biopsies from patients with different forms of Charcot-Marie-Tooth disease, type 1, (CMT1), as compared to others with inflammatory neuropathies and controls. The most notable changes consisted in the overexpression of ErbB2 and ErbB3 by SCs of nerves from CMT1A patients. These findings are consistent with an impairment of SC differentiation and expand the molecular phenotype of CMT1A. The upregulation of these receptors may play a role in the inhibition of myelination or in the promotion of recurrent demyelination and axonal damage.

  • Tubulin nitration in human gliomas.
    Publication Date: 06/02/2006, on Neuroscience letters
    by Fiore G, Di Cristo C, Monti G, Amoresano A, Columbano L, Pucci P, Cioffi FA, Di Cosmo A, Palumbo A, d'Ischia M
    DOI: 10.1016/j.neulet.2005.10.011

    Immunohistochemical and biochemical investigations showed that significant protein nitration occurs in human gliomas, especially in grade IV glioblastomas at the level of astrocytes and oligodendrocytes and neurones. Enhanced alpha-tubulin immunoreactivity was co-present in the same elements in the glioblastomas. Proteomic methodologies were employed to identify a nitrated protein band at 55 kDa as alpha-tubulin. Peptide mass fingerprinting procedures demonstrated that tubulin is nitrated at Tyr224 in grade IV tumour samples but is unmodified in grade I samples and in non-cancerous brain tissue. These results provide the first characterisation of endogenously nitrated tubulin from human tumour samples.

  • Drawing double images: a case of anosognosia for diplopia.
    Publication Date: 01/02/2006, on European journal of neurology
    by Lepore M, Conson M, Grossi D, Trojano L
    DOI: 10.1111/j.1468-1331.2006.01148.x

  • Detergent-resistant membrane domains but not the proteasome are involved in the misfolding of a PrP mutant retained in the endoplasmic reticulum.
    Publication Date: 01/02/2006, on Journal of cell science
    by Campana V, Sarnataro D, Fasano C, Casanova P, Paladino S, Zurzolo C
    DOI: 10.1242/jcs.02768

    Inherited prion diseases are neurodegenerative pathologies related to genetic mutations in the prion protein (PrP) gene, which favour the conversion of PrP(C) into a conformationally altered pathogenic form, PrP(Sc). The molecular basis of PrP(C)/PrP(Sc) conversion, the intracellular compartment where it occurs and how this process leads to neurological dysfunction are not yet known. We have studied the intracellular synthesis, degradation and localization of a PrP mutant associated with a genetic form of Creutzfeldt-Jakob disease (CJD), PrPT182A, in transfected FRT cells. PrPT182A is retained in the endoplasmic reticulum (ER), is mainly associated with detergent-resistant microdomains (DRMs) and is partially resistant to proteinase K digestion. Although an untranslocated form of this mutant is polyubiquitylated and undergoes ER-associated degradation, the proteasome is not responsible for the degradation of its misfolded form, suggesting that it does not have a role in the pathogenesis of inherited diseases. On the contrary, impairment of PrPT182A association with DRMs by cholesterol depletion leads to its accumulation in the ER and substantially increases its misfolding. These data support the previous hypothesis that DRMs are important for the correct folding of PrP and suggest that they might have a protective role in pathological scrapie-like conversion of PrP mutants.