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Biomedical subjects

E Cattaneo

Publications and source records attributed to E Cattaneo.

At least 37 records · Page 2Linked to original sources
PubMed2000

HTLV-II down-regulates HIV-1 replication in IL-2-stimulated primary PBMC of coinfected individuals through expression of MIP-1alpha.

The influence of human T-cell leukemia/lymphoma virus type II (HTLV-II) in individuals also infected with HIV-1 is poorly understood. To evaluate the reciprocal influence of HTLV-II and HIV-1 infection, primary peripheral blood mononuclear cell (PBMC) cultures from coinfected individuals were established in the presence of interleukin 2 (IL-2). In these cultures, the kinetics of HTLV-II replication always preceded those of HIV-1. Noteworthy, the kinetics of HIV-1 production were inversely correlated to the HTLV-II proviral load in vivo and its replication ex vivo. These observations suggested a potential interaction between the 2 retroviruses. In this regard, the levels of IL-2, IL-6, and tumor necrosis factor-alpha (TNF-alpha) were measured in the same coinfected PBMC cultures. Endogenous IL-2 was not produced, whereas IL-6 and TNF-alpha were secreted at levels compatible with their known ability to up-regulate HIV-1 expression. The HIV-suppressive CC-chemokines RANTES, macrophage inflammatory protein-1alpha (MIP-1alpha), and MIP-1beta were also determined in IL-2-stimulated PBMC cultures. Of interest, their kinetics and concentrations were inversely related to those of HIV-1 replication. Experiments were performed in which CD8(+) T cells or PBMCs from HTLV-II monoinfected individuals were cocultivated with CD4(+) T cells from HIV-1 monoinfected individuals separated by a semipermeable membrane in the presence or absence of antichemokine neutralizing antibodies. The results indicate that HTLV-II can interfere with the replicative potential of HIV-1 by up-regulating viral suppressive CC-chemokines and, in particular, MIP-1alpha. This study is the first report indicating that HTLV-II can influence HIV replication, at least in vitro, via up-regulation of HIV-suppressive chemokines. (Blood. 2000;95:2760-2769)

Acquired Immunodeficiency Syndrome↗
PubMed2000

Gene therapy of experimental brain tumors using neural progenitor cells.

Glioblastomas, the most frequent and malignant of primary brain tumors, have a very poor prognosis. Gene therapy of glioblastomas is limited by the short survival of viral vectors and by their difficulty in reaching glioblastoma cells infiltrating the brain parenchyma. Neural stem/progenitor cells can be engineered to produce therapeutic molecules and have the potential to overcome these limitations because they may travel along the white matter, like neoplastic cells, and engraft stably into the brain. Retrovirus-mediated transfer of the gene for interleukin-4 is an effective treatment for rat brain glioblastomas. Here, we transferred the gene for interleukin-4 into C57BL6J mouse primary neural progenitor cells and injected those cells into established syngeneic brain glioblastomas. This led to the survival of most tumor-bearing mice. We obtained similar results by implanting immortalized neural progenitor cells derived from Sprague-Dawley rats into C6 glioblastomas. We also documented by magnetic resonance imaging the progressive disappearance of large tumors, and detected 5-bromodeoxyuridine-labeled progenitor cells several weeks after the injection. These findings support a new approach for gene therapy of brain tumors, based on the grafting of neural stem cells producing therapeutic molecules.

Animals↗
PubMed2000

Upregulation and activation of Stat6 precede vascular smooth muscle cell proliferation in carotid artery injury model.

The role of signal transducers and activators of transcription (STAT) proteins in modulating proliferation and differentiation of various cell types in the hematopoietic system and the central nervous system has been well established. In contrast, the pathophysiological role of these proteins in vascular proliferative diseases has remained unproven, despite in vitro observations emphasizing the involvement of the STAT system in mediating vascular smooth muscle cell (VSMC) proliferation. On the basis of our previous observations demonstrating the occurrence of a specific modulation of Stat6 protein during the proliferative, migratory, and differentiation phases of the developing brain, we investigated whether Stat6 protein is present and modulated in arterial tissue challenged by perivascular injury. The time course of expression and localization of Stat6 after arterial injury was analyzed by immunohistochemistry, Western blot analysis, and confocal microscopy. Six hours after injury, the expression of Stat6 was markedly increased. This overexpression preceded the onset of VSMC proliferation and was downregulated starting from 7 days after injury, coincident with the decline of VSMC proliferation. Moreover, early after injury, Stat6 was predominantly localized at the nuclear level, denoting its functional activation. Conversely, Stat6 staining at later time points was largely cytosolic, suggesting silencing effects of this signaling pathway. These data indicate that Stat6 signaling may contribute to the modifications of gene expression underlying VSMC activation in the context of acute vascular proliferative diseases.

Animals↗
PubMed1999

Signalling through the JAK-STAT pathway in the developing brain.

The JAK -STAT (Janus kinase-signal transducer and activator of transcription) signalling pathway that is stimulated by cytokines has been much investigated in haematopoietic cells, but recent data indicate that this pathway is also present and active during neuronal and glial differentiation. Furthermore, it is now clear that growth factors other than the classical cytokines can act through this pathway and that physiological inhibitors of this signalling cascade exist. Thus, the JAKs, the STATs and their specific inhibitors could be molecules with important roles in the CNS.

Aging↗
PubMed1999

Expression of the JAK and STAT superfamilies in human meningiomas.

OBJECT: The goal of this study was to investigate whether the janus kinase/signal transducer and activator of transcription (JAK/STAT) signal transduction pathway is present and active in meningiomas. The results of these investigations are important for all meningioma therapies that, similar to interferon-alpha-2B (IFNalpha-2B), depend on activation of this pathway for their effect. The authors were interested in evaluating the importance, if any, of the JAK/STAT pathway in the biology and therapy for these tumors. METHODS: Total proteins were extracted from 17 meningioma samples and the levels of JAKs and STATs were determined by using Western blot analysis. Levels of these proteins in meningiomas were compared with those found in normal dura. The JAKs and STATs (with the exception of Jak3 and Tyk2) were present both in the dura and in the meningiomas studied. In tumors JAK and STAT levels were always significantly higher than those found in normal dura. Differences in relative levels were found when meningiomas were subdivided according to the current neuropathological criteria and the highest levels were found in transitional meningiomas. The authors also investigated, using tyrosine-phosphorylated Statl and Stat3 antibodies, whether STATs were activated in meningiomas and normal dura in vivo. Their results indicate that both Statl and Stat3 are phosphorylated in vivo in meningiomas and in the dura. Furthermore, in vitro experiments in which two independent short-term cultures obtained from freshly dissected meningioma samples were used indicated that Statl and Stat3 are phosphorylated in response to treatment with IFNalpha-2B. Exposure of meningioma cells to IFNalpha-2B leads to nuclear translocation of tyrosine-phosphorylated Statl and Stat3, as demonstrated by immunocytochemical analysis. CONCLUSIONS: The results of this study indicate that the JAK and STAT families of proteins are important effectors in brain tumors and support the idea that the effects of IFNalpha in vivo are direct and not mediated by the immune system. This suggests a role for modulation of STAT transcription factors in inhibiting meningioma cell proliferation.

Acute-Phase Proteins↗
PubMed1999

Diagnostic value of viral culture, polymerase chain reaction and western blot for HIV-1 infection in 218 infants born to HIV-infected mothers and examined at different ages.

In a prospective longitudinal 10-year (1988 to 1998) study, 308 sequential blood samples from 218 infants born to HIV-1 seropositive women were examined by blood culture, polymerase chain reaction (PCR) and Western Blot (WB) for HIV-1 infection within the first month of life (no. 47 specimens), at 2-6 (no. 125), 7-18 (no. 80), and > 18 (no. 56) months after birth. Clinical status at follow-up after the initial diagnosis of HIV infection was also evaluated. Vertically transmitted HIV infection was diagnosed in 45 children (24 children were diagnosed before 18 months of age), whereas 173 were found to be uninfected (transmission rate 20.6%). Sensitivities of viral culture, PCR and WB were 95.2%, 97.8%, 94.4%, and specificities were 99.5%, 97.6% and 20.7%, respectively. Thus, cumulative positive predictive values (PPV) of blood culture, PCR and WB were 97.5%, 88.2% and 23.4%, while negative predictive values (NPV) were 99.0%, 99.6% and 100.0%, respectively. In view of defining the optimal time of sampling for a correct diagnosis of HIV infection, a PPV of 100.0% was achieved earlier by viral culture (2-6 months of age) than by PCR (7-18 months of age). Meanwhile, a NPV of 100% was obtained earlier by PCR (within the first month of age) than by viral culture (2-6 months). These results indicate that a combination test strategy requiring two blood samples analyzed by viral culture and PCR may confirm or exclude HIV perinatal infection within the first 2 months of life rather than being delayed to later times. Clinical follow-up was performed in 35 children, of whom 7 developed a rapidly progressive disease, 23 showed a slow progression, while 5 children are still younger than 5 years and do not present severe clinical symptoms.

AIDS Serodiagnosis↗
PubMed1998

Retroviral-mediated transfer of the galactocerebrosidase gene in neural progenitor cells.

Globoid cell leukodystrophy (GCL or Krabbe disease) is a recessive disease caused by mutations of the lysosomal enzyme galactocerebrosidase (GALC) and twitcher is the murine model of GCL. We have prepared retroviral packaging cell lines to transduce the GALC gene. Retroviral transduction restored GALC activity in GCL fibroblasts and increased such activity to very high levels in immortalized neural progenitor cells (ST14A cells). GALC activity was also normalized in twitcher fibroblasts co-cultured with ST14A cells over-expressing GALC, demonstrating that this enzyme is secreted and can be imported efficiently by GALC-deficient cells. These results give the necessary background to evaluate the therapeutic effect in twitcher of brain grafting of neural progenitor cells engineered to release high levels of GALC.

3T3 Cells↗
PubMed1998

Members of the JAK/STAT proteins are expressed and regulated during development in the mammalian forebrain.

The presence and activation of members of the Janus Kinases/Signal Transducers and Activator of Transcription proteins in response to specific cytokines is currently the focus of intense investigation in the hematopoietic system. Although some evidence suggests that cytokines might play an important role in brain development and brain pathologies, very limited information is available on the presence of the JAK/STAT proteins in the Central Nervous System. Here we provide Western blot and immunohistochemistry data on the presence of Jak2 in vivo in the immature brain, its expression being greater in early stages of the embryonic life and gradually diminishing towards adulthood. Conversely, Jak1 was found expressed at a lower level compared to Jak2 and not modulated during brain maturation. Western blot data also show that specific members of the STAT family, the cytoplasmic substrates of the Janus Kinases, are present in vivo and that the extent of their expression is modulated differently at various stages. In particular, Stat6 protein levels were markedly attenuated at advanced stages of differentiation, as well as in the adult brain, with respect to early embryonic life. On the contrary, Stat3 levels did not vary. Analysis of Statl and Stat5 proteins showed a more complex expression pattern. These data indicate that members of the JAK/STAT proteins are present and modulated in vivo in the embryonic and postnatal brain, therefore supporting their role in the modulation of gene expression during the different stages of brain maturation.

Animals↗
PubMed1998

Generation and characterization of embryonic striatal conditionally immortalized ST14A cells.

Neural progenitor cells have been isolated from the embryonic central nervous system (CNS) of several mammalian species. These exhibit properties of immature cells, including expression of the intermediate filament protein Nestin, the ability to self renew, and to give rise to terminally differentiated cell types. In this study we describe some of the properties of ST14A cells, which were established via retroviral transduction of the temperature-sensitive mutant of the SV40 Large T Antigen into primary cells derived from the embryonic day 14 (E14) rat Striatum primordia. At 33 degrees C, ST14A cells proliferate and express Nestin, whereas at the nonpermissive temperature, cell growth becomes restricted in coincidence with the disappearance of the immortalizing oncoprotein. We also describe the ability of ST14A cells to differentiate and express MAP2. Furthermore, we analyzed the expression of specific growth factors and growth factor receptors in the ST14A cells, and found that nerve growth factor (NGF) and Trk receptors are most commonly expressed.

Animals↗
PubMed1998

Evolutionary rate and genetic heterogeneity of human T-cell lymphotropic virus type II (HTLV-II) using isolates from European injecting drug users.

Seven new Italian and two new British HTLV-II isolates were obtained from injecting drug users and the entire long terminal repeat (LTR) region was sequenced. Restriction analysis showed that all the Italian isolates are of the IIb subtype, whereas the British isolates are of the IIa subtype. To understand whether the further differentiation of each two principal HTLV-II subtypes in several subgroups could be statistically supported by phylogenetic analysis, the neighbor-joining, parsimony, and maximum likelihood methods were used. The separation between IIa and IIb is very well supported by all three methods. At least two phylogenetic subgroups exist within the HTLV-IIa and at least three within the HTLV-IIb subtype. In the present analysis, no statistical support was obtained for additional phylogroups. Two particular subgroups seem interesting because they include all European and North American injecting drug user strains within the IIa and IIb subtypes, respectively. These data confirm that European HTLV-II infection among drug users is probably derived from North America. They also suggest that though a certain differentiation by restriction analysis in different subgroups is possible, carefully interpreted phylogenetic analyses remain necessary. Using the likelihood ratio test, a molecular clock for the drug user strains was calibrated. A fixation rate between 1.08 x 10(-4) and 2.7 x 10(-5) nucleotide substitutions per site per year was calculated for the IIa and IIb injecting drug user strains. This is the lowest fixation rate so far reported for RNA viruses, including for HIV, which typically range between 10(-2) and 10(-4).

Biological Evolution↗
PubMed1998

Emerging roles for SH2/PTB-containing Shc adaptor proteins in the developing mammalian brain.

In mammalian systems, SH2-containing cytoplasmic signalling molecules are known to play an important role in determining cell responsiveness to the environment. In particular, following activation of a receptor protein tyrosine kinase (RPTK), proteins like Shc and Grb2 bind to phosphotyrosine residues of stimulated receptors, thereby activating downstream components of specific signalling pathways. The ShcA gene was identified in 1992 and was found to encode three proteins with properties of adaptor molecules coupling RPTKs to Ras. Early data obtained in non-neuronal cells have revealed that Shc and Grb2 proteins are highly expressed and activated in all cells. However, recent analyses of ShcA mRNA and protein in the developing brain revealed progressive downregulation of their expression during differentiation from neuroblasts to neurons. Conversely, the two newly identified Shc homologues (ShcB/Sli and ShcC/Rai) are highly expressed in the mature brain.Thus, variations in the intracellular levels of adaptor proteins might represent one of the mechanisms by which a differentiating cell changes its ability to respond to a given factor, allowing a cell to choose between proliferation and differentiation.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Basal ganglia precursors found in aggregates following embryonic transplantation adopt a striatal phenotype in heterotopic locations.

Transplantation of immature CNS-derived cells into the developing brain is a powerful approach to investigate the factors that regulate neuronal position and phenotype. CNS progenitor cells dissociated from the embryonic striatum and implanted into the brain of embryos of the same species generate cells that reaggregate to form easily recognizable structures that we previously called clusters and cells that disperse and integrate as single cells into the host brain. We sought to determine if the neurons in the clusters differentiate according to their final location or acquire a striatal phenotype in heterotopic positions. We transplanted dissociated cells from the E14 rat medial and lateral ganglionic eminences, either combined or in isolation, into the E16 embryonic rat brain. At all time points, we found clusters of BrdU- and DiI-labelled donor cells located in the forebrain and hindbrain, without any apparent preference for striatum. Immunocytochemical analyses revealed that cells in the clusters expressed DARPP-32 and ARPP-21, two antigens typically co-expressed in striatal medium-sized spiny neurons. In agreement with observations previously noted by several groups, isolated cells integrated into heterologous host areas do not express basal ganglia phenotypes. These data imply that immature striatal neuronal progenitors exert a community effect on each other that is permissive and/or instructive for development of a striatal phenotype in heterotopic locations.

Animals↗
PubMed1997

Expression and activation of SH2/PTB-containing ShcA adaptor protein reflects the pattern of neurogenesis in the mammalian brain.

The adult mammalian brain comprises many functionally distinct neuronal types, which are generated during development as a result of a coordinated signaling cascade that drives neuroblasts from proliferation into differentiation. We investigated whether and how ShcA adaptor proteins, which are known to function as initiators of the Ras signaling cascade in various nonneuronal systems where they have been considered to be expressed ubiquitously, are involved in the proliferative and differentiative phases of the developing brain. We found that in the forebrain expression and activation of ShcA proteins were strictly regulated during embryonic development, both temporally and spatially. The mRNAs encoded by the ShcA gene were expressed exclusively within an area to which active proliferation of immature neuroblasts was confined, the ventricular zone. In postnatal and adult brain, ShcA mRNAs and proteins were present only faintly. In the adult olfactory epithelium, in which neuronal cell renewal occurs throughout life, ShcA remained strongly expressed. These phenomena were peculiar to ShcA, since Grb2 adaptor protein remained expressed at constant level throughout development. The embryonically expressed ShcA proteins were functionally active, since p52(ShcA) became phosphorylated on tyrosine and associated with Grb2 following intraventricular injection of epidermal growth factor in the embryonic brain. Our data indicate that, through an orderly pattern of expression, ShcA gene products may play a role in the control of the switch between proliferation and differentiation of brain neuroblasts.

Adaptor Proteins, Signal Transducing↗
PubMed1997

Limited efficacy of the HSV-TK/GCV system for gene therapy of malignant gliomas and perspectives for the combined transduction of the interleukin-4 gene.

The growth of U-87 or C6 gliomas co-implanted in nude mice with retroviral producer cells (VPC) expressing the herpes simplex virus-thymidine kinase (HSV-tk) gene is only partially impaired by treatment with ganciclovir (GCV). The effect of GCV is even less evident when C6 and VPC are co-implanted into the rat brain. Furthermore, tumors from C6 cells carrying the HSV-tk gene are not eradicated by GCV, although they remain sensitive to GCV when replated in vitro. These limits of the HSV-tk/GCV system in glioma gene therapy may be due to insufficient gene transfer and/or insufficient delivery of GCV to glioma cells. Combination of HSV-tk and one or more cytokines may improve the antitumor efficacy. Among cytokines, interleukin-4 (IL-4) has already been shown to be active against gliomas. In nude mice, GCV treatment inhibited tumor growth more effectively after co-injection of C6 cells with a mixture of VPC transducing IL-4 and HSV-tk genes than after co-injection with either IL-4 or HSV-tk VPC only. In immunocompetent Sprague-Dawley rats, co-injection of IL-4 VPC and C6 cells was also effective in inhibiting the growth of C6 brain tumors, 38% of the animals surviving for at least 2 months. Furthermore, increased and prolonged antitumor efficacy was obtained by transducing both IL-4 and HSV-tk genes.

Animals↗
PubMed1997

Survival, integration, and differentiation of neural stem cell lines after transplantation to the adult rat striatum.

The in vivo properties of four different neural stem cell lines, generated from embryonic striatum or hippocampus by immortalization with the temperature-sensitive (s) A58/U19 allele of the SV40 Large T-antigen, have been studied with respect to their ability to survive, differentiate, and integrate after transplantation to the adult rat striatum. The cells were labeled with [3H]thymidine prior to grafting, and combined autoradiography and immunohistochemistry was used to characterize their phenotypic differentiation within the adult brain environment. The results show that all four types of cells survived well, up to at least 1.5-6 months postgrafting, without any signs of tissue perturbation or tumor formation. The cells underwent, on average, 2-3 cell divisions during the first 5 days after implantation and exhibited extensive migration over a distance of 1-1.5 mm from the injection site to become morphologically integrated with the surrounding host striatum. The cell number and tissue distribution attained by 2 weeks remained stable for up to 6 months postgrafting with the exception of one cell line, which showed a 40% loss of cells between 2 and 6 weeks. Twice the number of [3H]thymidine-labeled cells were recovered when the cells were grafted into a 1-week-old excitotoxic striatal lesion, probably due to an increased proliferation of the cells in response to the neuron-depleting depleting lesion. The immortalized cells behaved as multipotent neural progenitors. The vast majority of the cells developed a glial-like morphology, 6-14% being clearly GFAP-positive; however, a small but consistent proportion of them (1-3%) expressed MAP-2 and exhibited neuron-like morphology. In mature transplants about 75-80% of the grafted cells were located in the striatal grey matter, and 10-15% in white matter, some of which are proposed to have differentiated into oligodendrocytes. Remaining 5-10% occurred around small blood vessels (resembling pericytes) and in the subventricular zone underneath the ependyma of the lateral ventricle. It is concluded that the ts cell lines are highly suitable for intracerebral transplantation and that they allow the creation of a regionally confined cellular chimeras where the graft-derived glial cells become stably integrated with the resident glial cell matrix.

Animals↗
PubMed1997

Molecular analysis of HTLV-I and HTLV-II isolates from Italian blood donors, intravenous drug users and prisoners.

Using molecular methods three or five major variants of HTLV-I have been identified; moreover two subtypes of HTLV-II defined as HTLV-IIa and HTLV-IIb with six variants within each of these groups have been described. In the present study we analysed proviral DNA obtained from the peripheral blood mononuclear cells (PBMCs) of a significant group of Italian intravenous drug users (IVDUs), prison inmates and blood donors (BDs) who were HTLV antibody positive. Restriction fragment length polymorphism (RFLP) of amplified LTR region with ApaI, NdeI, DraI, SacI and MaeIII endonucleases was used to define the HTLV-I subtypes, while the different variants of HTLV-IIa and -IIb were defined by RFLP of the LTR region with the AvaII, BglI, SauI, XhoI and BanII endonucleases. The four HTLV-I isolated from BDs were characterized as C type. All the 11 HTLV-II detected in the IVDUs were HTLV-IIb4, while among the prisoners one HTLV-IIb5 and five HTLV-IIb4 were found. Interestingly, in the BDs group two HTLV-IIa0 and one HTLV-IIb4 were detected. It should also be noted that 82% of the IVDUs and 50% of the prisoners were coinfected with HIV, while all the BDs were HIV negative. These data indicate that HTLV-IIb4 is the predominant genotype in Italian IVDUs and prisoners, while the significant variability observed in the BD HTLV-II isolates could be due to the different source of infection among this group.

Blood Donors↗