1986 — 1988 |
Shafit-Zagardo, Bridget |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Brain-Specific Genes and Cns Differentiation @ Yeshiva University, Albert Einstein College of Medicine |
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1989 — 1991 |
Shafit-Zagardo, Bridget |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Second Messengers in Astrocytes and Precursor Cells
The goal of this proposal is to understand the role of second messenger systems in the regulation of glial fibrillary acidic protein(GFAP) and in the maturation of bipotential precursor cells from the nervous system in vitro. GFAP, the astrocyte specific intermediate filament (IF), is an major component of the astrocyte cytoskeleton. It is developmentally regulated and is elevated in most neurologic disease and brain traumas. Defining GFAP regulation in cultured cells will permit a clearer understanding of how GFAP expression is regulated in normal astrocytes and in disease states. The effects of agents which modulate cAMP or protein kinase C on GFAP RNA in primary astrocyte cultures and in the human astrocytoma cell line HTB-17 are being studies. Northern blot analysis of steady-state RNA levels, together with nuclear run-off experiments to assess relative transcription rates, indicate that cAMP, stimulated by treatment of cells with forskolin plus isobutylmethylxanthine (IMX) positively regulates GFAP mRNA at the post- transcriptional level. In contrast, GFAP steady-state mRNA is dramatically reduced in astrocytes and HTB-17 cultures treated with the phorbol ester PMA (10nM). This regulation is also post-transcriptional. Recently serum has been found to inhibit the effect of cAMP-stimulatory agents. Therefore we plan to refine our model system through the use of chemically defined (CD) medium, minus fetal calf serum. The exact nature of post-transcriptional up-regulation and down-regulation of GFAP mRNA will be determined. To investigate a possible role for second messengers in the in vitro maturation of bipotential precursor cells from the nervous system, two types of precursors will be grown in CD medium containing agents which modulate cAMP, protein kinase C and/ or calcium. One type of precursor, the AC-36A cell line, has the capacity to express either glial or neuronal characteristics; while the other, a bipotential precursor derived from neonatal rat forebrain, can become either astrocytic or oligodendrocytic, depending on culture conditions. We will follow the fate of these precursors in the presence of the various agents using immunocytochemical and DNA markers, as well as morphologic criteria. These studies will provide insight into the molecular mechanisms by which extracellular stimuli, such as cell-cell contact and growth factors, induce commitment of nervous system precursors to particular lineages.
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1993 — 1997 |
Shafit-Zagardo, Bridget |
N/AActivity Code Description: No activity code was retrieved: click on the grant title for more information |
Regulation and Function of Neuronal Maps @ Yeshiva University, Albert Einstein College of Medicine
9311806 Shafit-Zagardo A neuron has numerous processes, axons and dendrites, which allows each neuron to communicate with other neurons. The cytoskeleton of a neuron is essential for maintaining these processes. Microtubule-associated proteins are a highly specialized family of cytoskeletal proteins found in the processes of neurons. The major microtubule-associated protein found in dendrites is MAP-2. Glutamate is a neurotransmitter molecule that functions in signaling between neurons. Receptors for glutamate are present in the dendrites of many neurons and when activated, they trigger a series of changes within the neuron such as increases in calcium and modulation of certain intracellular messengers. These changes can result in changes in the architecture of the dendrites. This project will test the hypothesis that activation of the glutamate receptor results in changes in MAP-2, which ultimately results in changes in the form of the neuron. The results from this study will supply insights into the mechanisms responsible for development of specific patterns of connections between cells in the nervous system. *** te with ot ! ! F v v 8 Times New Roman Symbol & Arial " Univers (WN) t t t " h J E p 8 Steve McLoon, IBN William Proctor, IBN
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1999 — 2002 |
Shafit-Zagardo, Bridget |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Novel Oligodendrocyte Protein--Implications For Ms
Multiple Sclerosis (MS) is a paralyzing disease affecting young adults. While a number of experimental drugs are available to minimize the devastation of the disease's course the cause of MS is unknown. A central issue for the treatment of MS is whether oligodendrocytes or resident oligodendrocyte precursors have the potential to remyelinate axons following episodes of demyelination. We have identified a novel variant of human high molecular weight (HMW) microtubule-associated protein-2, designated MAP-2+13, and have generated monoclonal antibodies specific to this splice form. Immunocytochemistry with light and electron microcopy have demonstrated MAP-2+13 staining in human fetal oligodendrocytes during process extension and active myelination, and in numerous oligodendrocytes adjacent to a zone of demyelination in sections from MS lesions. MAP-2+13 is either minimally or not expressed in oligodendrocytes in the normal adult CNS. The hypothesis to best tested in this proposal is that MAP-2+13 is required for the elaboration of oligodendrocyte processes during myelination and that it can be used as a marker for myelinating and remyelinating oligodendrocytes. To determine whether MAP-2+13 expression parallels myelination within the developing CNS, a range of fetal ages will be examined by double-label immunofluorescence and Confocal microscopy, immunoblotting and electron microscopy. MAP-2+13 expression in MS lesions will be extensively examined to determine if the expression correlates with remyelination. Studies will correlate MAP-2+13 expression with the type of lesion and will be compared with age-matched, non neurologic sections. Rat progenitor cells and primary oligodendrocyte cultures will permit the study of MAP-2+13 in a well characterized in vitro system. Analysis will include how changes in MAP-2+13 expression correlate with process outgrowth and oligodendrocyte maturation. These studies permit the examination of a newly identified MAP-2 form in oligodendrocytes and the potential to gain insight into the extension of processes during myelination and disease. Attempts to identify developmentally regulated genes and to understand the regulation involved in the extension of myelinating processes is beneficial for both our understanding of normal CNS development and for treating demyelinating diseases such as Multiple Sclerosis.
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