Daniel Jon Liebl
University Of Miami School Of Medicine
Project start date: 2004-07-01
Project end date: 2016-01-31
Sponsored Links Excellgen http://Excellgen.com
EPHRINS REGULATE STEM CELL PROLIFERATION FOLLOWING TBI
Daniel Jon Liebl, Associate Professor
University Of Miami School Of Medicine, Po Box 016960 (r-64), Miami, Fl 33101
Grant 5R01NS049545-05 from National Institute Of Neurological Disorders And Stroke
Abstract: Five million Americans are presently living with disability as a result of traumatic brain injury (TBI). The majority of TBI research focuses on the factors that influence the onset of pathology, while fewer studies have addressed the mechanisms that promote recovery. Cellular loss associated with TBI is significant barrier to overcome, and recent advancements in stem cell transplantation and cellular rejuvenation provide a potential therapy for recovery. However, the mechanisms that regulate stem cell functions are still ill defined, and even less is known how the functions are altered following TBI. The studies outlined in this proposal will examine a family of molecules, Ephrins and their receptors (Eph receptors), which have been implicated throughout the developing CNS. We have recently demonstrated that these molecules are also expressed in adult stem/progenitor cell, adult neuroblasts and in surrounding tissues. We hypothesize that ephrinB3 may function to arrest cell cycle and in turn promote post-mitotic differentiation. Furthermore, following injury the over expression of ephrinB3 and/or its receptors may limit the ability of endogenous stem/progenitor cell to proliferate. We will employ gene-targeted knockout mice to investigate their functions within the subventricular zone (SVZ). Aim 1 of this application will investigate their function in regulating endogenous adult stem/progenitor cell proliferation in the SVZ, and whether the absence of ephrinB3 can alter cell cycle protein concentrations. Aim 2 will employ an in vitro assay to examine the mechanisms of action for ephrinB3 and signaling pathways used to regulate cell cycle arrest. Aim 3 will examine the role of ephrinB3 and its Eph receptor(s) in controlling cell proliferation following TBI. These studies will provide essential mechanistic information on the function of ephrinB3 and its receptor(s) to regulate stem/progenitor cell proliferation in the normal and injured brain, and could lead to therapeutic treatments to promote recovery in the chronically injured patient
Keywords: 21+ years old; Address; Adult; American; Body Tissues; Brain; Cek-8 Kinase; Cell Communication and Signaling; Cell Count; Cell Cycle Arrest; Cell Cycle Proteins; Cell Division Cycle Proteins; Cell Function; Cell Growth in Number; Cell Locomotion; Cell Migration; Cell Movement; Cell Multiplication; Cell Number; Cell Process; Cell Proliferation; Cell Signaling; Cell physiology; Cell-Cycle Regulatory Proteins; Cells; Cellular Function; Cellular Migration; Cellular Physiology; Cellular Process; Cellular Proliferation; Data; EPH; Encephalon; Encephalons; Eph Family Receptors; Eph Receptor Ligands; Eph Receptor Tyrosine Kinase; Eph Receptors; Eph-A4 Receptor Tyrosine Kinase; EphA4 Protein; EphA4 Receptor; Ephrin Receptor A4; Ephrin Receptors; Ephrins; Family; Gene Targeting; Gene Transcription; Genetic Transcription; Goals; Human, Adult; Immigrations; In-Migration; Injury; Intracellular Communication and Signaling; Knock-out; Knockout; Knockout Mice; Lead; Life; Mediating; Mice, Knock-out; Mice, Knockout; Mitotic; Mother Cells; Motility; Motility, Cellular; Nervous System, Brain; Neuronal Differentiation; Null Mouse; Pathology; Patients; Pb element; Population; Progenitor Cell Transplantation; Progenitor Cells; Proliferating; RNA Expression; Receptor Protein; Receptor, EphA4; Receptors, Eph Family; Recovery; Rejuvenation; Research; Role; Sek-1 Receptor Tyrosine Kinase; Signal Pathway; Signal Transduction; Signal Transduction Systems; Signaling; Site; Slice; Specificity; Stem Cell Transplantation; Stem cell transplant; Stem cells; Subcellular Process; Sum; System; System, LOINC Axis 4; Targetings, Gene; Therapeutic; Tissues; Transcription; Transcription, Genetic; Translating; Translatings; Trauma, Brain; Traumatic Brain Injury; Traumatic encephalopathy; adult human (21+); base; biological signal transduction; cdc Proteins; cell motility; disability; experience; gain of function; heavy metal Pb; heavy metal lead; in vitro Assay; injured; language translation; loss of function; migration; neuroblast; receptor; receptor function; social role; stem; subventricular zone; traumatic brain damage
Project start date: 2005-08-04
Project end date: 2010-04-30
Budget start date: 1-MAY-2009
Budget end date: 30-APR-2010
PFA/PA: PAS-03-172
5R01NS049545-05 (2009): $296958
5R01NS049545-03 (2007): $296958
5R01NS049545-02 (2006): $330029
Grants awarded to Daniel Jon Liebl
REGULATION OF SYNAPTIC FORMATION & EFFICACY FOLLOWING TRAUMATIC BRAIN INJURY
Daniel Jon Liebl, Associate Professor
University Of Miami School Of Medicine, Po Box 016960 (r-64), Miami, Fl 33101
Abstract: Seven million Americans are presently living with disability as a result of traumatic brain injury (TBI) with 500,000 new patients admitted every year. TBI is a devastating disability that leads to sensory and motor dysfunction, learning and memory impairment, and cognitive deficits. At the point of injury, these defects result in focal cell losses, however, damage is not limited to this immediate region. In fact, TBI often results in global changes that include reactive glial cells and synaptic dysfunction. Our studies are designed to examine the role of reactive astrocytes in regulating synaptic function after TBI. We hypothesize that ephrins and Eph receptors function in the homeostasis between the astrocytes and pre-/post-synaptic terminals. Following TBI, we believe ephrins and Eph receptors function to regulate synaptic stability and plasticity. To address this hypothesis, we will employ both in vitro and in vivo approaches using genetically modified mice. Specifically, aim 1 will examine the role of ephrins and Eph receptors in regulating astrocytes synthesis and release of glutamate, D-serine, and signaling intermediates in normal and stretch-injured in vitro conditions. These molecules are an important aspect of astrocyte regulated synaptic homeostasis. Aim 2 will examine whether synaptic formation and function differ when grown on a monolayer of sham or injured astrocytes, as well as examining the role of ephrins/Eph receptor by using genetically mutant astrocytes and/or neurons. Finally, aim 3 will examine how our findings translate to the complex CNS environment by examining synaptic formation/function and astocyte functions using gain and loss-of-function approaches and an in vivo controlled cortical impact injury. In summary, our studies are important in determining whether ephrins and Eph receptors are key regulators of synaptic formation and function in the tri-synaptic interactions between astrocytes, pre- and post-synaptic terminals. RELEVANCE (See instructions); Please refer to proposal page ´2´ for overall project relevance to public health
Keywords: Acute; Address; American; Ammon Horn; Antimorphic mutation; Astrocytes; Astrocytus; Astroglia; Autoregulation; Axon Terminals; Brain; CNS Injury; Cek-8 Kinase; Cell Communication and Signaling; Cell Signaling; Cells; Central Nervous System Injury; Clinical; Co-culture; Cocultivation; Coculture; Coculture Techniques; Cognitive deficits; Communication; Complex; Cornu Ammonis; D Glutamate; Data; Defect; Development; Dominant Negative; Dominant-Negative Mutant; Dominant-Negative Mutation; Dysfunction; EPH; Encephalon; Encephalons; Environment; Eph Family Receptors; Eph Receptor Ligands; Eph Receptor Tyrosine Kinase; Eph Receptors; Eph-A4 Receptor Tyrosine Kinase; EphA4 Protein; EphA4 Receptor; Ephrin Receptor A4; Ephrin Receptors; Ephrins; Foundations; Functional disorder; Future; Glia; Glial Cells; Gln; Global Change; Glutamates; Glutamine; Hippocampus; Hippocampus (Brain); Homeostasis; In Vitro; Injury; Injury of central nervous system; Instruction; Intracellular Communication and Signaling; Knock-out; Knockout; Knockout Mice; Kolliker`s reticulum; L-Glutamate; L-Glutamine; L-Serine; Learning; Life; Link; Maintenance; Maintenances; Mammals, Mice; Mediating; Memory Deficit; Memory impairment; Methods; Mice; Mice, Knock-out; Mice, Knockout; Motor; Murine; Mus; NRVS-SYS; Nerve Cells; Nerve Endings, Presynaptic; Nerve Unit; Nervous System; Nervous System, Brain; Nervous system structure; Neural Cell; Neurocyte; Neuroglia; Neuroglial Cells; Neurologic Body System; Neurologic Organ System; Neurons; Non-neuronal cell; Null Mouse; Patients; Physiological Homeostasis; Physiopathology; Play; Presynaptic Terminals; Principal Investigator; Public Health; Pyruvate; Pyruvates; Q. Levoglutamide; Receptor Protein; Receptor, EphA4; Receptors, Eph Family; Recovery; Regulation; Research Design; Role; Seizures; Sek-1 Receptor Tyrosine Kinase; Sensory; Serine; Signal Transduction; Signal Transduction Systems; Signaling; Slice; Specificity; Stretching; Study Type; Synapses; Synaptic; Synaptic Boutons; Synaptic Terminals; System; System, LOINC Axis 4; TEM; Therapeutic Intervention; Translating; Translatings; Transmission Electron Microscopy; Trauma, Brain; Traumatic Brain Injury; Traumatic encephalopathy; axon growth; axonal growth; biological signal transduction; central nervous system injury; controlled cortical impact; dalton; disability; gain of function; hippocampal; in vivo; in vivo Model; inhibitor; inhibitor/antagonist; injured; injury and repair; insight; intervention therapy; language translation; loss of function; monolayer; mutant; nerve cement; neuronal; neuroprotection; novel; pathophysiology; public health medicine (field); receptor; receptor function; response; serine racemase; social role; study design; synapse formation; synapse function; synaptic function; synaptogenesis; traumatic brain damage
Budget start date: 1-AUG-2010
Budget end date: 31-JUL-2011
5P50NS030291-17_5441 (2010): $283839
ROLE OF EPHRINS & EPH IN REGULATING SYNAPTOGENESIS AFTER TRAUMATIC BRAIN INJURY
Daniel Jon Liebl
University Of Miami School Of Medicine 1507 Levante Avenue Coral Gables, Fl 33124
Grant 2P50NS030291-11A10009 from National Institute Of Neurological Disorders And Stroke IRG: NSD
Abstract: Five million Americans are presently living with disability as a result of traumatic brain injury (TBI). The majority of TBI research focuses on the factors that influence the onset of pathology, while fewer studies have addressed the mechanisms that promote recovery. Understanding the mechanisms that function to regulate growth and plasticity in the central nervous system (CNS) will provide the fundamental basis for promoting regeneration following TBI. The studies outlined in this proposal will examine a family of molecules, Ephrins and their receptors (Eph receptors), which have been implicated in developmental patterning, axonal guidance and fasciculation, midline development, and synaptic plasticity throughout the developing CNS. We have recently demonstrated that these molecules may also function to regulate growth and plasticity in the injured CNS. We will employ gene-targeted knockout mice to investigate their functions within the precise circuitry of the hippocampus. Aim 1 of this application will investigate their function in regulating mossy fiber axonal growth, dendritic growth, and synaptic plasticity. Aim 2 and Aim 3 will evaluate Ephrin and Eph receptor function following TBI. We will first examine these connections in an established model of mild (3.5 m/s) controlled cortical impact brain injury as they relate to hippocampal dysfunction. We will then examine whether Ephrins and Eph receptors function to mediate regrowth of mossy fiber afferents. These studies will provide essential information on the mechanisms that function to regulate regeneration following TBI, and could lead to therapeutic treatments to promote recovery in the chronically injured patient.
Keywords: brain injury, cell growth regulation, membrane protein, neural plasticity, protein structure function, protein tyrosine kinase, receptor expression, synaptogenesis, trauma, hippocampus, mossy fiber, nervous system regeneration, neuroanatomy, laboratory mouse, transgenic animal
Project start date: 2002-07-19
Project end date: 2007-06-30
Ephrins Regulate Stem Cell Proliferation Following TBI
Daniel Jon Liebl
University Of Miami School Of Medicine 1507 Levante Avenue Coral Gables, Fl 33124
Grant 1R01NS049545-01A1 from National Institute Of Neurological Disorders And Stroke IRG: CNNT
Abstract: Five million Americans are presently living with disability as a result of traumatic brain injury (TBI). The majority of TBI research focuses on the factors that influence the onset of pathology, while fewer studies have addressed the mechanisms that promote recovery. Cellular loss associated with TBI is significant barrier to overcome, and recent advancements in stem cell transplantation and cellular rejuvenation provide a potential therapy for recovery. However, the mechanisms that regulate stem cell functions are still ill defined, and even less is known how the functions are altered following TBI. The studies outlined in this proposal will examine a family of molecules, Ephrins and their receptors (Eph receptors), which have been implicated throughout the developing CNS. We have recently demonstrated that these molecules are also expressed in adult stem/progenitor cell, adult neuroblasts and in surrounding tissues. We hypothesize that ephrinB3 may function to arrest cell cycle and in turn promote post-mitotic differentiation. Furthermore, following injury the over expression of ephrinB3 and/or its receptors may limit the ability of endogenous stem/progenitor cell to proliferate. We will employ gene-targeted knockout mice to investigate their functions within the subventricular zone (SVZ). Aim 1 of this application will investigate their function in regulating endogenous adult stem/progenitor cell proliferation in the SVZ, and whether the absence of ephrinB3 can alter cell cycle protein concentrations. Aim 2 will employ an in vitro assay to examine the mechanisms of action for ephrinB3 and signaling pathways used to regulate cell cycle arrest. Aim 3 will examine the role of ephrinB3 and its Eph receptor(s) in controlling cell proliferation following TBI. These studies will provide essential mechanistic information on the function of ephrinB3 and its receptor(s) to regulate stem/progenitor cell proliferation in the normal and injured brain, and could lead to therapeutic treatments to promote recovery in the chronically injured patient.
Keywords: brain injury, cell growth regulation, cell migration, cell proliferation, ephrin, protein structure function, regeneration, stem cell, trauma, receptor expression, gel electrophoresis, gene targeting, genetically modified animal, green fluorescent protein, immunoprecipitation, in situ hybridization, laboratory mouse, molecular /cellular imaging, polymerase chain reaction, tissue /cell culture, western blotting
Project start date: 2005-08-04
Project end date: 2010-04-30
1R01NS049545-01A1 (2005): $325096