Richard S. Morrison - US grants

Intrinsic neurons of the central nervous system (CNS) do not successfully regenerate following trauma. The lack of regeneration accounts, in part, for the poor prognosis of patients who have sustained serious injury to the spinal cord or brain. The isolation of molecules that enhance neuronal survival and facilitate process outgrowth could significantly improve a patient's response and outlook following CNS injury. This proposal is based on our unique finding that a protein mitogen, basic fibroblast growth factor (bFGF), enhances survival and neurite extension from CNS neurons in vitro. Nerve growth factor is the only other (Homogeneous) trophic molecule reported to affect CNS neurons, but its action in the CNS is restricted to a small population of cells in the basal forebrain. In order to exploit bFGF as a potential therapeutic agent it is necessary to know more about its basic biology, including the types of neurons that respond to it and the mechanism by which it works. Therefore, we plan to survey defined regions of the CNS for the presence of neurons responsive to bFGF by utilizing primary cell culture techniques. Neurons will be identified using immunocytochemical techniques employing antibodies to defined neuronal antigens. The cells will be further characterzied and classified according to subtype by analyzing their expression of neurotransmitters and neuropeptides using immunocytochemical methods. Upon characterization of the neuronal cultures we will begin to analyze the mechanism of bFGF action by studying its receptor. Receptor binding is the first step in initiating the action of most polypeptide hormones. An 125I-bFGF tracer will be developed and used for demonstrating and identifying the bFGF receptor on neurons and neurolgia. Molecular characterization will be performed on solubilized receptors using SDS polyacrylamide-gel electrophoresis of receptor covalently attached to tracer by chemical cross-linking. We will correlate the response of neuronal populations in vitro with receptor expression in vivo by combining the 125I-bFGF tracer with frozen sections of rat brain. In this manner the ontogeny and distribution of bFGF receptors in the CNS will be accurately mapped.

Intrinsic neurons of the central nervous system (CNS) do not successfully regenerate following trauma. The lack of regeneration accounts, in part, for the poor prognosis of patients who have sustained serious injury to the spinal cord or brain. The isolation of molecules that enhance neuronal survival and facilitate process outgrowth could significantly improve a patient's response and outlook following CNS injury. This proposal is based on our unique finding that a protein mitogen, basic fibroblast growth factor (bFGF), enhances survival and neurite extension from CNS neurons in vitro. Nerve growth factor is the only other (Homogeneous) trophic molecule reported to affect CNS neurons, but its action in the CNS is restricted to a small population of cells in the basal forebrain. In order to exploit bFGF as a potential therapeutic agent it is necessary to know more about its basic biology, including the types of neurons that respond to it and the mechanism by which it works. Therefore, we plan to survey defined regions of the CNS for the presence of neurons responsive to bFGF by utilizing primary cell culture techniques. Neurons will be identified using immunocytochemical techniques employing antibodies to defined neuronal antigens. The cells will be further characterzied and classified according to subtype by analyzing their expression of neurotransmitters and neuropeptides using immunocytochemical methods. Upon characterization of the neuronal cultures we will begin to analyze the mechanism of bFGF action by studying its receptor. Receptor binding is the first step in initiating the action of most polypeptide hormones. An 125I-bFGF tracer will be developed and used for demonstrating and identifying the bFGF receptor on neurons and neurolgia. Molecular characterization will be performed on solubilized receptors using SDS polyacrylamide-gel electrophoresis of receptor covalently attached to tracer by chemical cross-linking. We will correlate the response of neuronal populations in vitro with receptor expression in vivo by combining the 125I-bFGF tracer with frozen sections of rat brain. In this manner the ontogeny and distribution of bFGF receptors in the CNS will be accurately mapped.

The molecular mechanisms underlying the development of human brain neoplasms remain poorly understood, so that, advances in surgery, radiation and chemotherapy have not successfully impacted on their lethality. There is good evidence that the more malignant varieties of such tumors express multiple chromosomal abnormalities. In some tumors, genetic aberrations have been associated with alterations in growth factors or their receptors. Consistent with this finding, we have recently demonstrated that human glioma cells express high levels of basic fibroblast growth factor (bFGF), a potent mitogen and angiogenic protein. In contrast to other growth factors previously identified in human gliomas, bFGF expression in gliomas is elevated relative to its expression in other human tumor types. this proposal is aimed at testing the hypothesis that the expression of bFGF correlates with a transformed phenotype in malignant human gliomas. We will determine: 1) if bFGF expression is modified in human glioma cells relative to normal glia and other types of brain tumors, 2) if bFGF expression is directly related to the degree of malignancy in human glioma cells, and 3) if alterations in bFGF expression can effect the phenotype of normal and transformed human glial cells. bFGF expression will be studied at the RNA and protein level using polymerase chain reaction and Western blots respectively. A correlation of bFGF expression with the degree of phenotypic malignancy in gliomas could provide a prognostic marker for this tumor. Furthermore, the expression of bFGF and its receptor in glioma cells may provide a potential avenue for interrupting the lethal cycle of glioma growth and invasion.

The p53 tumor suppressor gene is a sequence-specific transcription factor that activates the expression of genes engaged in promoting growth arrest or cell death in response to genotoxic stress. A role forp53- related modulation of neuronal viability has been suggested by the finding that p53 expression is elevated in damaged neurons in acute models of injury such as ischemia and epilepsy and in brain tissue samples derived from patients with chronic neurodegenerative diseases. Moreover, the absence of p53 has been shown to protect neurons from a wide variety of acute toxic insults consistent with the hypothesis from our previous applications that p53 expression regulates neuronal viability after injury. Our long-range objective is to assess the consequences of p53 gene expression in the CNS. However, the downstream molecular consequences of p53 activation in neurons remain obscure. Our proteomic analyses demonstrate that p53 is associated with injury-induced alterations in the expression of proteins that reside in or associate with the mitochondria. Mitochondrial dysfunction is a hallmark of stress-induced neuronal toxicity. Therefore, in the present application, we propose to test the hypothesis that p53 promotes neuronal cell death by altering the expression or distribution of proteins that regulate mitochondrial integrity. We will specifically: 1) Determine if the p53 protein promotes a loss of mitochondrial integrity and changes in cytoskeletal organization through the induction and mitochondrial translocation of cofilin; 2) Determine if the p53 protein promotes mitochondrial dysfunction and neuronal death by regulating the N-BAK protein; 3) Determine if dynamin- related protein-1 (Drp1) promotes mitochondrial dysfunction and neuronal death, and 4) Identify p53- dependent changes in the mitochondrial proteome. These studies will help elucidate the mechanism by which p53 regulates neuronal survival and activity in response to injury and neurologic disease.

Loss or mutation of the p53 tumor suppressor gene is thought to be an important event in the malignant transformation of human astrocytes. The loss of wild-type p53 function may render cells more susceptible to genetic instability, predisposing them to neoplastic transformation. However, the specific genetic alterations that occur in astrocytes following the loss of p53 function have not been defined. Using glass- based high-density cDNA arrays we identified a novel gene that was significantly upregulated in malignant mouse astrocytes relative to normal mouse astrocytes. This gene was identified as pescadillo, which was first characterized as a gene that was essential for embryonic development in zebrafish. A yeast homologue of pescadillo has also been identified and its deletion is lethal in yeast. Preliminary data from our laboratory has shown that the pescadillo protein is highly expressed in human brain tumor cells suggesting that it may represent an important molecular change in human glial tumors. Although pescadillo contains several significant structural motifs including the presence of a BRCA1 carboxy terminus domain, its function and its relationship to malignancy remain unknown. The aim of the present proposal is to characterize the biochemical function and the cellular role of pescadillo in normal and malignant astrocytes. We will: 1) Determine if the pescadillo protein is abnormally expressed in human glial tumors; 2) Determine if pescadillo regulates the proliferation and invasiveness of normal and malignant astrocytes; 3) Determine if pescadillo regulates the cellular response of astrocytes to DNA damage and alters their sensitivity to chemotherapeutic agents; and 4) Characterize the biochemical function of pescadillo by analyzing its binding partners using a yeast two hybrid and proteomics screen. Since pescadillo represents a novel gene whose activity is essential for yeast viability and zebrafish development, elucidating its cellular role may provide unique insights into the process of neoplastic transformation and may provide a new target for suppressing the growth of human brain tumors.

DESCRIPTION (provided by applicant): Due to the importance of reversible phosphorylation in virtually all aspects of cell function and development, there exists a need to develop better methods to identify and quantify changes in the phosphorylation states of proteins on a proteome-wide level. In this R21 project, we will develop and apply new approaches, termed phosphopeptide isotope coded affinity tags (PhIAT), for obtaining proteome-wide identification and precise measurements of differences in the phosphorylation states of the proteins extracted from p53+/+ mouse cortical neurons. Our approach will utilize proteome-wide stable isotope and biotin labeling of phosphopeptides to enable high affinity isolation of phosphopeptides. We will use data-dependent tandem mass spectrometry (MS/MS) and Fourier transform ion cyclotron resonance mass spectrometry (FTICR/MS) to identify phosphorylated peptides that can function as accurate phosphopeptide mass tags (APMTs) to uniquely identify phosphorylated proteins. The approach will provide for high affinity isolation of phosphopeptides, be at least 3 orders of magnitude more sensitive than existing 2-D PAGE methodologies, and be able to rapidly identify and measure relative phosphorylation states for thousands of proteins in a single analysis. We will apply this technology to quantify differences in the relative phosphorylation state of proteins from p53+/+ and p53-/- cortical neurons treated with an apoptotic stimulus. The later phase of this project will develop methods that concomitantly combine PhIAT and ICAT labeling to identify proteins in glutamate or camptothecin treated p53+/+ cortical neurons that undergo changes in either their phosphorylation state or relative abundance compared to non-treated cells. By combining the PhIAT and ICAT strategies on treated p53+/+ neurons, we will be able to identify proteins that undergo a change in phosphorylation without a corresponding change in expression, or vice versa. The development of this capability will ultimately provide the broadest present proteome coverage since changes in protein abundance, as well as changes in protein phosphorylation states will be identifiable in a single experiment.

DESCRIPTION (provided by applicant): Loss or mutation of the p53 tumor suppressor gene is an important event in the malignant transformation of human astrocytes. The loss of wild-type p53 function renders cells more susceptible to genetic instability, predisposing them to neoplastic transformation. However, the specific genetic alterations that occur in astrocytes following the loss of p53 function have not been defined. While rapid and sensitive techniques for the large-scale analysis of gene expression at the mRNA level have been developed, there has been no comparable technique for proteins. mRNA abundance is only one factor that determines how much of a specific protein is present in a cell. Indeed, protein expression levels often show poor correlation with Mrna expression levels. Therefore, it is desirable to obtain information on the proteome level to gain a more complete understanding of a particular process at the molecular level. The aim of the present proposal is to show the feasibility of developing and utilizing new proteomics technology to identify proteins that are altered in cultured postnatal cortical astrocytes during the process of malignant transformation. In the present application, we propose to:l ) Develop and integrate new methods for the extraction and stable isotope and biotin labeling of proteins expressed in p53+/+ and p53-/- mouse cortical astrocytes; 2) Apply differential stable isotope and biotin labeling technology to obtain proteome-wide precise measurements of differences in the protein expression profiles extracted from normal (p53+/+) and malignant mouse astrocytes (p53-/-). Protein expression profiles will be compared with mRNA expression profiles to demonstrate the degree to which changes in mRNA expression are conserved at the protein level, providing insight regarding the extent of post-transcriptional regulation in the process of malignant transformation; and 3) Validate proteome-wide precise measurements of differences in the protein expression profiles extracted from normal (p53+/+) and malignant mouse astrocytes (p53-/-) using immunological and biochemical techniques. The development of extraction protocols and mass spectrometric techniques that can be used to reproducibly measure global changes in protein expression in brain tissue may provide unique insights into the process of neoplastic transformation and may provide new targets for suppressing the growth of human brain tumors.

DESCRIPTION (provided by applicant): The tumor suppressor p53 is recognized as an important regulator of apoptosis in acute and chronic neurological insults and neurodegenerative disorders. However, the downstream molecular consequences of p53 activation in neurons still remain obscure. Our proteomic analyses have demonstrated that DNA damage-induced neuronal apoptosis involves a p53-dependent increase in the expression of proteins that comprise histone deacetylase (HDAC) complexes. This data suggests that p53 might promote neuronal dysfunction/cell death by activating histone deacetylase activity. Our preliminary studies indeed demonstrate that histone deacetylase inhibitors protect against p53-mediated cell death. In contrast HDAC activity is generally elevated in cancer cells, and HDAC inhibition actually induces p53-dependent cell death. In the present application, based on this novel finding of the neuron-specific mode of HDAC inhibitor actions, we propose to test the hypothesis that p53-mediated cell death signaling in neurons is dependent on histone deacetylase activity by examining how HDAC inhibitors block neuronal cell death. We will specifically: 1) Determine if HDAC inhibitors selectively protect neurons from p53-mediated cell death, 2) Determine if HDAC inhibitors directly block p53 activation and/or transcriptional activity required for p53-dependent cell death in neurons; and 3) Determine if HDAC inhibitors prevent p53- dependent changes in mitochondrial integrity. The aims of this proposal will help us to better understand the molecular sites and mechanism of HDAC inhibitor action, which will enhance the utility of these inhibitors as therapeutic agents for neurological diseases and injury. PUBLIC HEALTH RELEVANCE: Histone deacetylase inhibitors protect neurons from dying in several mouse models of human neurodegenerative disease. However, the mechanism by which histone deacetylase inhibitors prevent cell death is not understood. A better understanding of how these compounds work and the types of diseases or injuries that they protect against would enhance their range of action and their effectiveness. We propose to determine how histone deacetylase inhibitors block neuronal cell death which could lead to the development of new therapeutic agents for treating neurological diseases and nervous system injury.

Benefits of the Core: 1) P30 users will have automatic web-based access to the results of their own proteomic experiments, and results from any collaborators with whom they wish to share data; 2) Results will be visualized in the form of interactive graphical networks that show proteins that interact with a given protein; 3) Clicking on a given protein will initiate a search of related information on the Internet, which will be displayed as additional links on the graphical display.

[unreadable] DESCRIPTION (provided by applicant): The purpose of this proposal is to establish a University of Washington Research Core facility that provides essential proteomics and bioinformatics infrastructure support for a large contingent of scientists interested in mapping protein-protein interactions in the nervous system. Many of these investigators conduct research involving disease genes and a defined analysis of their binding partners will help investigators to understand how alterations in these genes modulate neuronal and glial structure and function during the course of nervous system disease and injury. This research is clearly essential to the mission of the NINDS. Three research cores and one administrative core will provide support for the research programs and will stimulate interactions and collaborations among investigators. Core A, the molecular virology core, will provide a repository for all of the expression plasmids needed to tag proteins and map protein-protein interactions and validate binding interactions using a variety of biochemical methods. This core will also generate and titer lentivirus for each expression construct providing a valuable reagent for expressing tagged proteins in cells that are traditionally difficult to transfect. Core B, the mass spectrometry core, will provide mass spectrometry-based identification of protein complexes purified using the pull down techniques associated with the various tagged proteins generated in Core A. Core C, the bioinformatics core, will provide comprehensive analysis of protein sequence data, molecular interactions, pathways, biological structures, genetic maps, homology information, and functional annotations of proteins identified in the various pull down assays. The research cores will be supported by an administrative core that will oversee the operation of each research core, organize user meetings, steering committee meetings, organize an annual research symposium, provide clerical, fiscal and personnel support, and prepare reports to the funding agency. [unreadable] [unreadable] [unreadable]

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We are constantly looking to employ new methods to enhance the separation and identification of peptides. We are fortunate to have Dr. David Goodlett as a core director as he is actively involved in the development of new mass spectrometry techniques (please see his biosketch and letter). We have also recruited an internationally recognized expert on mass spectrometry and bioinformatics, Dr. Timothy Veenstra, as an external consultant. These two individuals will insure that Core C provides state of the art advances to our end users. One future direction will involve incorporating stable isotope labeling methods, e.g. isotope coded affinity tag (ICAT) or iTRAQ methods, as well as so-called label-free methods as recently described in Dr. Goodlett's laboratory (Foss et al., In Press, Nature Genetics). This will allow us to provide information on the relative levels of expression of proteins in a complex and discern bona fide members of the complexes from non-specific, contaminating proteins58. In addition, depending on our resources, it may be possible to provide global proteome analysis as we previously described for mouse cortical neurons57 and mouse astrocytes (McBee et al, In Press, Proteomics; see Morrison Biosketch).

The organizational scheme for the Administrative Core will consist of the Director and Associate Director supervising the Core Directors. The Steering Committee of the Neuroproteomics Center will consist of the Director, Associate Director, and the principal investigators of the qualifying projects as specified in the Program Announcement. The steering committee will establish guidelines to determine the most appropriate methods for providing access to the core facilities and services, and for prioritizing work within the cores as described on page 76.

DESCRIPTION (provided by applicant): Finding interventions that improve outcome from ischemic stroke has proved to be challenging and current treatment is limited to thrombolysis, aspirin, and management in a stroke unit. An ideal stroke therapeutic would minimize damage to mature neurons and white matter, and also maximize the generation of new neurons from endogenous progenitors. Recent findings of our own and of others, both in vitro and in animal models of stroke, suggest that histone deacetylase (HDAC) inhibitors meet these criteria. Drug administration protects isolated neurons from induced apoptotic cell death and white matter from oxygen-glucose deprivation, results in improved histologic and functional outcomes following cerebral ischemia, and appears to drive 'neuronal' differentiation of multipotent neural progenitor cells. Therefore, we hypothesize that HDAC inhibition in stroke may have acute effects (to ameliorate white matter excitotoxicity), and in the intermediate and longer term, added benefit by reducing apoptosis and encouraging regeneration. As a number of HDAC inhibitors are either already approved by the FDA (vorinostat), or well-advanced in clinical trials (MS-275) for other reasons, then re- purposing one or more of these drugs for stroke could be expedited. In addition, development of new and specific inhibitors is ongoing, especially against the Class I HDACs which are the focus of interest here. Studies described in Aim 1 are designed to identify the specific HDACs which account for the beneficial actions of these inhibitors, using in vitro and ex vivo preparations in which individual HDACs are knocked down with shRNA and transduced cells/tissues then subjected to oxygen-glucose deprivation. Having identified specific HDACs, we shall explore in Aim 2 the potential substrates and mechanisms responsible for the beneficial actions of HDAC inhibition. Finally, in the last aim we consider whether treatment of mice with MS-275, a Class I HDAC inhibitor, preserves anatomic integrity and promotes long term functional (motor, sensory, cognitive) recovery from transient cerebral ischemia (middle cerebral artery occlusion), and whether restoration of function correlates with the extent of 'neuronogenesis'. Two recently developed transgenic lines, p53+/+ and p53 -/- mitoCFP mice, will be employed so that we can monitor ischemic pathology in CFP+ fiber tracts, assess drug-associated changes in mitochondrial frequency and distribution within neuronal cell bodies and their processes, and also determine whether HDAC inhibition ultimately involves targets in addition to neuronal p53. PUBLIC HEALTH RELEVANCE: This proposal is submitted in response to PA-08-099 Mechanisms of functional recovery after stroke, a funding opportunity to promote research to understand the processes of brain repair that lead to functional recovery in order to develop methods to optimize existing practices and to develop new approaches to improve post-stroke outcomes. Currently, there is no drug available to enhance neuroprotection and restore function following human stroke. Experimental animal studies suggest that broad inhibition of histone deacetylase (HDAC) activities in the brain following injury results in neuronal protection and also promotes the generation of new neurons. The purpose of the studies outlined in this proposal is to identify which HDACs are involved in order to select specific drugs to target these particular enzymes. Selected drugs will be tested to reveal what functional benefits they confer on the recovery of mice from stroke injury.

DESCRIPTION (provided by applicant): Accumulating evidence demonstrates that mitochondrial dysfunction is both associated with and causally related to neurodegeneration observed in response to injury and diseases affecting the brain. While disturbances in energy metabolism and ATP production have received significant attention, abnormalities are also being found in the regulation of mitochondrial dynamics which involves the processes of fusion and fission (fragmentation) affecting the shape and size of mitochondria. Importantly, mitochondrial fusion and fission are directly involved in ensuring their proper distribution, transport, and turnover. Considering how vital it is for neurons to have healthy mitochondria positioned at sites of energy demand, it is not difficult to imagine that genetic or epigenetic modifications that impair the regulation of mitochondrial fission and fusion could adversely affect neuronal connectivity, function and viability. We recently determined that neurons express two alternatively spliced forms of a mitochondrial fission regulating protein, Bif-1 (Bif-1b/c). Our preliminary data demonstrates that Bif-1b/c is lost in neurons in the penumbra (cerebral cortex) of mice subjected to middle cerebral artery occlusion (MCAO, stroke model). Importantly, the Bif-1-null condition enhanced neuronal cell death caused by MCAO, and DNA damage and Abeta cytotoxicity in culture. Conversely, Bif-1c overexpression confers significant protection against Abeta-mediated toxicity indicating that Bif-1 is required for normal neuronal function. The Bif-1b/c protein is significantly reduced in the parietal cortex (affected area) and in synaptosomes of sporadic Alzheimer's disease (AD) patients compared to aged matched non-AD patients. These changes in Bif-1b/c are also observed in the APPswe/PS1dE9 mouse AD model and in primary cortical neurons following addition of the toxic Abeta peptide. Moreover, in preliminary studies, Bif-1-null mice displayed significant cognitive impairment at one year of age and knockout of the Bif-1 homologue (endoB) in drosophila enhanced the toxicity of the toxic Abeta42 peptide based on an eye phenotype, but had no effect on flies expressing the non-toxic Abeta40 peptide. These findings demonstrate a potential neuroprotective function of Bif-1 and suggest that mitochondrial dysfunction associated with ischemic damage and AD may be due to reduced expression of Bif-1b/c. We propose to test the hypothesis that restoration of Bif-1c expression in neurons in an inducible transgenic mouse promotes neuronal survival, retention of mitochondrial integrity and enhances cognitive function in response to stroke and in a mouse model of AD. These studies will determine if Bif-1c has therapeutic actions for reducing injury and disease-induced damage.

Bax-interacting factor-1 (Bif-1) was initially identified as a protein that interacts with the pro-apoptotic protein Bax and has since been implicated in mitochondrial dynamics, autophagy and apoptosis in non-neuronal cells with its overall activity being pro-apoptotic. We recently reported the identification of novel neuron specific splice forms, Bif-1b and Bif-1c that have neuroprotective action. In contrast, Bif-1a, the only splice form expressed by non-neuronal cells, promotes apoptosis through interactions with the pro-apoptotic protein Bax. We reported reduced Bif-1b/c specifically in CNS regions predominantly affected by AD pathology, in brain regions adjacent to stroke-induced infarcts and also in aging brain. Interestingly, loss of Bif-1 alone is sufficient to cause age dependent behavioral deficits and synaptic degeneration in the mouse hippocampus. These findings suggest that the loss of Bif-1b/c may be instrumental in sensitizing neurons to a multitude of stresses associated with brain injury and disease. During the course of preliminary studies to identify and characterize Bif-1 interacting proteins in primary cortical neurons in culture we observed that protein crosslinking followed by immunoprecipitation of Bif-1a, Bif-1b and Bif-1c brought down a pro-survival member of the Bcl-2 family, Bcl-xL and mitochondrial fission factor (Mff). Bcl-xL represents the principal anti-apoptotic protein expressed in adult brain. Importantly, Bcl-xL maintains mitochondrial function and regulates neuronal metabolism by enhancing the efficiency of ATP production in mitochondria. Mff is a mitochondrial surface receptor for the fission promoting GTPase Drp1. In new preliminary studies with primary cortical neurons, in contrast to our previous studies with SH-SY5Y cells, only neuron-specific forms of Bif-1 interacted strongly with Bcl-xL and Mff, consistent with our previous studies showing that only Bif-1b and Bif-1c exhibit neuroprotective activity and promote mitochondrial elongation. These findings suggest that different Bif-1 isoforms may be endowed with distinct functions by virtue of having unique binding partners. Since little is known regarding the mechanism by which Bif-1 promotes neuronal viability, characterization of the Bif-1 interactome could provide additional clues to dissecting Bif-1?s novel function and mechanism of action in neurons. Here we propose to: i) use an integrated crosslinking and mass spectrometry approach to characterize and compare the interactome for neuron-specific and ubiquitous Bif-1 isoforms under normal and stressful conditions. This approach will allow us to extract isoform-specific differences in the Bif-1 interactome to identify selective interactions that are potentially responsible for the neuroprotective potency of neuron-specific Bif-1 isoforms and ii) validate the biological significance of interactions between Bif-1 and Bcl-xL and Mff. These studies will help elucidate some of the specific mechanisms by which alterations in the Bif-1 protein impact neuronal function and viability. Our long term goal is to identify inhibitor peptides and agonist/mimetic peptides for modulating functional interactions between Bif-1 and Bcl-xL or Mff to enhance brain function after injury and in CNS disease.