Douglas H. Smith - US grants

The equipment purchased (thermal cycler, a tissue culture enclose and a microcentrifuge) supports the use of PCR technology in a variety of laboratory classes recently introduced within a newly instituted B.S. degree program in Molecular Biology and Biotechnology. The program provides a link between the worlds of research and secondary education. Classes affected include Genetics, Biotechnology I and II and Immunology.

9454397 Zielinski BISCITS or Biotechnology Initiative for Systemic Change in the Teaching of Science is a program that will change the way our young people view modern technology in science. The first and foremost way to do this is enhance our nation's teachers ability to effect such change. In order to succeed, BISCITS will start by retraining the workforce at both the middle and high school level by recruiting teacher teams from school districts in the Pennsylvania area. This retraining has many facets. First, teachers need to become current and fluent about molecular biology and biotechnology subject matter and the types of employment open to those students wishing to pursue these areas as careers. Also, BISCITS will provide sessions discussing ethical issues that are being raised by biotechnology. BISCITS will make the teacher participants "biotechnology-literate."

DESCRIPTION (Adapted from applicant's abstract): Although cognitive dysfunction is one of the most debilitating sequela of traumatic brain injury, current treatments are limited in scope due to the lack of clearly understood mechanisms involved in the pathophysiology of traumatic brain injury. Such injury in young adults has been shown to induce delayed neurobehavioral sequelae, which may not become fully manifest until senescence. Clinically, age related cognitive deficits have been shown to be exacerbated following brain injury. In addition, development of neurodegenerative disorders appears to be more prevalent following brain trauma. Recent evidence suggests that much of the pathophysiological sequelae of traumatic brain injury may be due to alterations in endogenous neurochemical processes, including a marked release of excitatory amino acid transmitters which become toxic at high concentrations. The hippocampus, thought to be integrally involved in spatial learning and memory, and which is rich in excitatory amino acid receptors, has been shown to be selectively vulnerable to damage following experimental brain injury. Using a model of fluid percussion brain injury in the rat, the applicants found a correlation between the severity of post traumatic cognitive dysfunction and the extent of selective loss of neurons in the hippocampus. In addition, they have demonstrated that excitatory amino acid receptor antagonists may attenuate post traumatic memory dysfunction and spare hippocampal and neuronal loss. However, little is known about the long-term histopathology of brain injury or of the efficacy of excitatory amino acid antagonists to improve long-term functional outcome. Also, little is known about the role that brain injury may play in the development of age related cognitive dysfunction and/or neurodegenerative disorders, and no current therapies are available that may augment post traumatic cognitive ability. The specific aims of the present proposal are, 1) to characterize the effects of experimental brain injury in young adult rats on the development of cognitive dysfunction and histopathology through senescence. The applicants will accomplish this using Morris water maze testing to determine cognitive status of brain injured animals, and by examining the brains of these animals for neuronal cell loss, neuronal degeneration, blood brain barrier breakdown, microtubule associated protein (MAP2) loss and beta-amyloid 4 disposition, which is observed in Alzheimer's disease. 2) To evaluate the differences in cognitive and histopathologic outcome between young and old animals shortly following brain injury. Positive results from these studies may lead to novel approaches for acute and chronic management of post traumatic cognitive dysfunction. 3) To evaluate the long-term efficacy of selective excitatory amino acid antagonists and excitatory amino acid antagonist release inhibitors to attenuate post traumatic neuronal damage and cognitive dysfunction. 4) To evaluate the therapeutic efficacy of cognition enhancers on persisting post traumatic cognitive dysfunction in young and aging rats.

Substantial interest in long-term pathologic changes following brain trauma has emerged due to recent evidence that neurodegeneration may be initiated by a single incident of brain injury. These neurodegenerative changes are particularly evident in patients suffering diffuse brain injury. Therefore, we propose to explore long-term neurodegeneration using a new model of non-impact head rotational acceleration in the pig that induces diffuse axonal pathology with and without coma. We have recently found that this model of brain trauma also produces neurodegenerative changes within one week following injury. These neurodegenerative changes include Abeta and tau accumulation in axons, Abeta plaque formation, tau accumulation in neurons, neurofilament inclusions in neurons, and possible phagocytosis of axons by neutrophils. Uniquely, these clinically relevant pathologic changes have not previously been found in other models of brain trauma. From these data, we have developed several testable hypotheses: 1) diffuse brain trauma will induce progressive Alzheimer's disease-like pathology (Abeta and tau accumulation) and Lewy body pathology (neurofilament cytoplasmic inclusions), 2) diffuse brain trauma will initiate a long- term deleterious immune response resulting in axon phagocytosis by both neutrophils and microglia, and 3) the extent of posttraumatic coma will be dependent on the angle of rotation and will correlate with the severity of brainstem injury. We propose to explore each of these hypotheses using multiple histologic and biochemical techniques, evaluating progressive neuropathologic changes over six months posttrauma. Success of these studies may reveal mechanistic links between brain trauma and neurodegenerative processes and facilitate the development of therapeutic and diagnostic techniques for diffuse brain injury.

DESCRIPTION: (Verbatim from the Applicant's Abstract) While traumatic brain injury is one of the leading causes of death and disability, mounting evidence suggest that brain trauma may also initiate insidiously progressive neurodegenerative processes. Brain trauma is a risk factor for developing Alzheimer's disease (AD) and can induce the acute formation of plaques composed of amyloid beta (Abeta), a primary brain pathology of AD. In the first four years of this grant using animal models of brain trauma, we have observed remarkable prolonged cognitive deficits, brain atrophy, neuron death, axon degeneration, and gliosis following injury. We have also made a novel finding of Abeta accumulation following experimental brain trauma. In the current application, we propose to use our experimental paradigms to further explore potential mechanisms and modulation of age-dependent neurodegenerative changes following brain trauma. Specifically, we propose to 1) continue our evaluation of the long-term effects of brain trauma on cognitive status and histopathology, 2) examine the long-term efficacy of brain trauma therapies, 3) evaluate the effects of age at the time of brain trauma on outcome, 4) evaluate the potential neurotoxicity of Abeta production following brain trauma. Success of these studies may reveal mechanistic links between brain trauma, age and neurodegenerative processes and provide a basis for the development of new therapeutic strategies.

DESCRIPTION (provided by applicant): Diffuse axonal injury (DAI) is one of the most common and important aspects of traumatic brain injury. However, little is known about the immediate and long-term consequences of this pathology, It has been shown that brain trauma increases the risk for developing Alzheimer's disease (AD), and can induce the rapid formation of amyloid-Beta (ABeta) plaques, a hallmark pathology of AD. Using a unique model of DAI in the pig developed in our laboratory, we have previously demonstrated a marked accumulation of ABeta in axons in association with ABeta plaques within days following injury. Our current preliminary data suggests that this process continues for at least six months following injury. Accordingly, ongoing axonal pathology may provide a persistent source of ABeta in the brain. In this application, we propose to evaluate mechanisms responsible for posttraumatic ABeta formation and determine the temporal disposition of ABeta and neurodegeneration. We will also evaluate the effects of reducing ABeta production on the extent of evolving pathology and, conversely, the effects of reducing axonal pathology on the extent of ABeta production and accumulation. To compliment the pig DAI model we have recently developed an in vitro model of "cultured axonal injury" (CAI) that induces trauma via tensile elongation of isolated axons. With this model we propose to examine the immediate and evolving events following axon stretch-injury, including mechanisms of posttraumatic calcium influx. In concert with the pig studies, we propose to use the CAI model to evaluate mechanisms of ABeta accumulation in damaged axons following injury. Collectively, our proposed studies may improve understanding of potential mediators of secondary injury shortly following DAI and provide insight into progressive pathologies induced by brain trauma.

[unreadable] DESCRIPTION (provided by applicant): There are an estimated 10,000 patients who suffer spinal cord injury (SCI) each year in the U.S. and approximately 250,000 chronic SCI patients. While a primary strategy to repair the spinal cord is to bridge the damage with axons, producing axons of sufficient length and number has posed a significant challenge. Here, we propose to refine and utilize a novel tissue engineering technique to create transplantable nervous tissue constructs for spinal cord repair. This technique was developed in our laboratory through work on the biomechanics of axonal stretch. The key of this procedure is to use a specially designed microstepper motor system to produce continuous mechanical tension on axons spanning two populations of neurons in culture. Using dorsal root ganglia (DRG) neurons, this technique has rapidly produced nerve tracts consisting of up to 106 axons grown at rates of up to 10mm/day and reaching a remarkable 10 cm in length. As such, these axons are of sufficient length and number to bridge even extensive nerve damage. As our core hypothesis, we propose that transplantation of these nervous tissue constructs may create new intraspinal circuits forming relays across spinal cord lesions and improve functional outcome. In our first aim, we will develop nervous tissue constructs composed of stretch-grown axons from fetal rat DRG neurons and encased in carefully selected hydrogels. We will then evaluate the survival and potential integration of these constructs following transplantation into a lesion formed by hemisection of the rat spinal cord. For Aim 2, we will determine the potential clinical applicability of the axon stretch-growth technique by creating nervous tissue constructs composed of adult human and rat stretch-grown DRG axons. The human neurons will come from both live patients and organ donors. Survival and integration of nervous tissue constructs from adult rats will be examined using the rat spinal cord hemisection model. In Aim 3 we will evaluate functional outcome following transplantation of optimized fetal and adult nervous tissue constructs using a model of complete spinal cord transection. If successful, our axonal stretch-growth approach could offer an important alternative, yet complimentary method, to repair the spinal cord by providing laboratory grown "off-the-shelf" living nervous tissue constructs ready for transplant. [unreadable] [unreadable] [unreadable]

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DESCRIPTION (provided by applicant): The continuing aim of the Brain Injury Training Grant (BITG) is to provide an excellent mentoring environment for highly motivated clinician and basic scientists to prepare them for careers in nervous system injury research. Our trainees acquire basic science research skills that address the etiology, pathogenesis, diagnosis, treatment, and prevention of injury to the nervous system, such as traumatic brain injury (TBI), cerebral ischemia (stroke) and spinal cord injury. Since its inception in 2003, the success of this program has continued to expand, with 11 trainees obtaining faculty positions (5 neurosurgeon clinician scientists and 6 Ph.D. scientists), 1 trainee has joined the NIH administration and 2 trainees have gone on to positions in the biomedical research industry. For this competing renewal of the BITG, we request continued funding for 4 postdoctoral fellowship slots (simultaneous) for individuals with a strong interest in studying injury to the nervous system. These positions will typically be filled by two neurosurgical residents during their strictly protected research trainin and two Ph.D. scientists. The BITG program administration will continue to be democratically governed by group vote of faculty mentors. Day-to-day management will be entrusted to an Executive Committee. For training, the research project will typically be based in an individual laboratory. Trainees will actively participate in selecting the mentor and laboratory. To become integrated with the greater BITG community, trainees will be encouraged to engage in multiple opportunities, such as seminars, courses, and scientific retreats. We also propose to greatly enhance our efforts on diversity recruitment. We have a newly designated Diversity Recruitment Liaison on our Executive Committee and we have developed strategies to increase awareness and engagement with diversity opportunities. Considering the growing understanding of the impact of nervous system injury on society, the BITG plays an important role in training future leaders in this area. In particular, the BITG provides a novel infrastructure involving a highly collaborative faculty and excellent facilities to train future clinical and basic research scientiss in nervous system injury.

? DESCRIPTION (provided by applicant): There is a growing recognition that mild traumatic brain injury (mTBI) or concussion is a major health issue, with over 2 million cases each year in the United States. Moreover, there is increasing concern that there may be a period of vulnerability after one mTBI, during which time a second mTBI may induce greatly exaggerated pathophysiological effects. We have used a multidisciplinary approach to generate experimental in vitro and in vivo models that replicate the mechanical loading conditions of mTBI in humans. With these models, we have recently identified that diffuse axonal injury (DAI) is a key pathology of single mTBI. In addition, we have shown that microtubule damage as well as dysregulation of sodium channels on axons following traumatic injury are watershed events contributing to axonal vulnerability, dysfunction and degeneration. Moreover, we have generated promising preliminary data indicating the utility of novel neuroimaging and serum biomarkers for the detection of brain damage in mTBI. Here, we propose to use these models to 1) investigate novel diagnostic techniques to evaluate axonal pathology in single and repetitive mTBI, and 2) explore the mechanistic roles of axonal cytoskeletal changes that may induce enhanced vulnerability that accounts for exacerbated damage with a repeat mTBI. Innovation: Success of the proposed studies could lead to 1) new diagnostic criteria to identify mTBI pathologies, 2) identify new pathologies and mechanisms of single and repetitive mTBI, and 3) reveal new therapeutic targets.

Although mild traumatic brain injury (MTBI) affects over 1 million victims each year in the United States, it is generally ignored as a major health issue. However, this 'mild'form of injury induces persisting neurocognitive dysfunction in many of these patients, exacting an enormous emotional and financial toll on society. Despite the prevalence and impact of MTBI, little is known about potential anatom ic or mechanistic substrates that are reflected by the clinical manifestations. We have assembled a unique multidisciplinary and multi-center team of investigators from the Center for Brain Injury and Repair (CBIR) at the University of Pennsylvania (Penn) and from Baylor College of Medicine in Houston to investigate two central hypotheses addressing clinical and mechanistic aspects of MTBI: 1) White matter injury, specifically diffuse axonal injury (DAI), is an important pathologic substrate of MTBI, and the extent and distribution of this injury will determine neurocognitive outcome, and 2) Axonal damage in MTBI is linked to mechanosensitive sodium channels;the persistent dysfunction of these channels will lead to short- and long-term axonal degeneration. To test these hypotheses of DAI in MTBI, we have organized the proposal into three projects (one clinical and two basic science) and two technical cores supporting neuroimaging and biomarker analyses. This Program represent a 'molecules to man'approach, using experimental models we have developed that span axon stretch injury in vitro to a mild head rotational acceleration TBI model in the pig. These models will be used in parallel investigations using non-invasive outcome measures of MTBI patients. This stepwise approach allows us to explore the evolving cellular and molecular effects of traumatic axon injury in a reduced model, confirm that these changes occur in vivo in the pig MTBI model, and extrapolate these findings to MTBI patients through comparison of non-invasive measures. Success of the proposed studies could lead to new diagnostic criteria to identify the pathologies and m echanisms in MTBI, predict long-term neurocognitive dysfunction after MTBI, and provide targets for new therapeutic interventions.

? DESCRIPTION (provided by applicant): Mounting evidence suggests that the long-term impact of traumatic brain injury (TBI) may be far worse than previously thought. A history of brain trauma increases an individual's risk of developing Alzheimer's disease (AD), and TBI can induce the rapid formation of amyloid-? (A?) plaques, a hallmark pathology of AD. Pioneering work from this grant has demonstrated that massive accumulations of amyloid precursor protein (APP) in damaged axons after TBI are accompanied by the very secretases that cleave APP to form A?. Uniquely, this anabolic process occurs within the axonal membrane compartment of humans with TBI and in animal models of TBI. However, although this axonal process persists for years after TBI, the frequency of A? plaques appears to diminish within months. This suggests that there is also a potential A? catabolic process after TBI. Indeed, we have shown in preliminary data using multiple models that neprilysin, the primary A? degrading enzyme, may have a key role in clearing A? following injury. In addition, preliminary human studies demonstrate stunning evidence that A? plaques reappear several years and even decades after TBI. From these collective data, we hypothesize that there is a long-term shifting balance between A? anabolism and catabolism after TBI. Remarkably, through preliminary examination we also found the other hallmark pathology of AD, neurofibrillary tangles (NFTs), in long-term survivors of TBI. This is further supported by the demonstration of NFTs chronically following injury in our unique swine model. This finding represents a significant new avenue in the exploration of mechanisms linking TBI and AD and is the first demonstration that NFT formation occurs chronically following just a single TBI. For this application, we propose a molecules-to-man approach to determine evolving mechanisms of AD-like pathologies after TBI. Through our longstanding collaboration between investigators at the University of Pennsylvania and Glasgow, UK, we will investigate long-term neuropathological changes after TBI, using the world's only comprehensive TBI human brain archive. In parallel interactive studies, we will examine well-characterized experimental models at the in vivo and in vitro level to determine the cellular and molecular mechanisms of A? plaque and NFT genesis. In addition, we will examine the effects of A? reduction after injury in experimental models with a view to therapeutic intervention. Success of these studies will provide insight into mechanisms that convert a single TBI into a progressive neurodegenerative disease.

DESCRIPTION (provided by applicant): Mounting evidence suggests a history of traumatic brain injury (TBI) can increase the risk of developing Alzheimer's disease (AD). A pathological clue linking these two disease states came with the observation that amyloid-beta (A2) plaques, a hallmark pathology of AD, could be found in patients within hours following TBI. Furthermore, excessive plaques can be observed, persisting even decades after the initiating trauma. More recently, we have identified that the A2- degrading enzyme, neprilysin, may play an important role in the emergence of plaques. It has also been demonstrated that just a single TBI can induce the delayed emergence of neurofibrillary tangles (the other hallmark pathology of AD) and stands as important evidence in the link between these two disease states. While AD-like pathologies after TBI have been studied primarily in younger adults, little is known about how the aged brain responds to trauma with regard to these pathologies. Using a unique human brain archive based in Glasgow, UK, we propose to examine post-mortem brain tissue of elderly individuals for AD-like pathologies following TBI. Specifically, we aim to 1. Examine for the hallmark pathologies of Alzheimer's disease (A2 plaques and NFTs) in individuals aged 60+ who have sustained a TBI. 2. Examine of A2 degrading enzyme, neprilysin, in individuals aged 60+ who have sustained a TBI, using immunohistochemistry and 3. Examine of the influence of polymorphisms of both the neprilysin gene Apolipoprotein E (ApoE) gene in predicting amyloid-2 plaque formation in individuals aged 60+ who have sustained a TBI. As AD is predominantly a disease of ageing, we hypothesize that older individuals will be have increased vulnerability to developing AD-like pathology post-TBI. Exploration of these mechanisms may provide an important basis for improving the clinical management and developing therapeutic opportunities for this unique subgroup of individuals. ) PUBLIC HEALTH RELEVANCE: Traumatic brain injury (TBI) is a risk factor for Alzheimer's disease (AD). Both Hallmark pathologies of AD - A2 plaques and neurofibrillary tangles, have been found following TBI. Preliminary data suggests older individuals may be an increased risk of these TBI-induced pathologies. Using a unique human brain archive, we propose to examine older individuals for AD-like pathologies following TBI. Potential findings may explain the worsened neurocognitive outcomes observed following TBI in older patients. Understanding the mechanistic basis of these processes is vital in the drive towards targeted therapeutic intervention - particularly as novel AD-therapies emerge into the clinical forum. )

? DESCRIPTION (provided by applicant): Although the term chronic traumatic encephalopathy (CTE) has only recently entered the research and common vernacular, the neuropsychiatric sequelae have been recognized for decades as dementia pugilistica (DP) in some individuals with careers in boxing. Yet, despite the intense new interest in `CTE', the number of reported cases has been surprisingly limited and there are no validated neuropathological diagnostic criteria to define it as a distinct disease entity. Notwithstanding this, there is a widely held, abeit unfounded, perception that repetitive TBI (rTBI) alone culminates in `CTE' and that `CTE' is primarily characterized by a unique tau pathology. However, multiple neuropathological features have been reported for DP/CTE beyond tau pathologies, including brain atrophy, amyloid-? plaques, TDP-43 pathologies and neuroinflammation. Furthermore, it is now recognized that almost all of these pathologies are observed in a proportion of cases years after just one moderate to severe single TBI (sTBI). As TBI-associated neurodegeneration has become a major health concern, there is a clear and pressing need to develop robust operational neuropathological criteria for diagnosis, which will, in turn, be critical to the success of all fuure mechanistic, diagnostic and interventional studies. Towards this end, we have assembled an international, multidisciplinary team of experts who provide unparalleled experience in both the study of long-term neurodegeneration after TBI, and the development of optimized assessment of common neuropathological diseases including Alzheimer's disease (AD). Through our team members, we have custodial access to the only comprehensive TBI brain archives in the US and UK that include both sTBI and rTBI cases as well as ~1500 longitudinally followed and extensively characterized autopsy confirmed cases of AD and related disorders for comparison. For our primary Aim 1, we will use a standardized approach successfully applied to AD, to generate baseline diagnostic neuropathological criteria using existing post-mortem material of sTBI and rTBI. In Aim 2 we will pursue biochemical, and genetic studies to explore potential associations with neuropathological outcomes from chronic TBI. In Aim 3 we will explore the temporal course of neuroinflammation to examine its potential role in progressive neurodegeneration following TBI. Finally, in Aim 4 will secure a networked archive of the extensive resources of data and biospecimens generated in Aims 1-3 for wider access across the research community.

SUMMARY AND RELEVANCE Traumatic brain injury (TBI) is recognized as the strongest environmental risk factor for neurodegenerative disease, including dementia of Alzheimer's disease (AD)-type. Correspondingly, the neuropathology of survival from TBI comprises a complex array of pathologies, including production and deposition of amyloid-beta (A?) often in association with axonal degeneration. Of particular note, pathologies in A? are recognized across all survival intervals, being present in patients dying in the acute phase post injury, in a proportion of longer term survivors of moderate to severe TBI and in a majority of patients with later stage, clinically significant CTE. Derived from amyloid precursor protein (APP), soluble A? is widely recognized as neurotoxic. As such, A? clearance is closely regulated via enzymatic degradation, direct absorption into blood and perivascular drainage. As a consequence, TBI-associated pathologies in A? may arise through either excess production, inefficient clearance or a combination of both. A feature common to all severities of TBI is diffuse axonal injury (DAI). As a consequence, there is interruption of axonal transport in damaged axons, which we have demonstrated is associated with rapid accumulation of APP and the secretases responsible for its processing to A?. Thus, within hours of TBI, there is the potential for release of large pools of neurotoxic A? as a consequence of DAI. Of note, among our most recent observations, we have demonstrated that axonal transport interruption is not restricted to the acute phase after injury, with evidence of continued axonal degeneration and associated APP transport interruption in material from survivors a year or more from TBI. As such, through axonal injury there is potential for TBI to initiate immediate and sustained A? production. However, though DAI is ubiquitous and may persist years after injury, only around 30% of patents develop A? plaque in the acute phase after TBI; these acute plaques appearing to diminish in the months following injury. In brain parenchyma, the principal enzyme responsible for A? degradation is neprilysin. Intriguingly, through our unique studies in human TBI, we have shown polymorphism in the neprilysin gene is associated with risk of amyloid plaque deposition in the acute phase post TBI. However, its relationship to late post-TBI pathologies is unknown and will be addressed in this proposal. In addition to enzymatic catabolism, clearance of soluble A? proceeds via exchange across the blood brain barrier (BBB) and through interstitial fluid drainage along perivascular pathways. In this regard, our preliminary studies in both human tissue and animal models suggest TBI is associated with significant and persisting BBB disruption in a high proportion of patients. As such, disturbance in the vasculature following TBI, might serve to alter A? transport across the BBB following injury. Our proposal extends our longstanding and successful collaboration between investigators at the University of Pennsylvania and University of Glasgow, UK. We propose to utilize the unique and comprehensive tissue resources of the Glasgow TBI Archive, which we will interrogate in studies directed to understanding processes contributing to A? genesis and clearance after injury across a spectrum of survivals. In parallel, through our well- characterized large animal model of TBI, we will pursue studies to determine the cellular and molecular mechanisms contributing to disturbance in A? processing and vascular injury after TBI. As TBI associated neurodegenerative disease is increasingly recognized as a major health concern, there is a clear and pressing need to better understand the persistent and evolving pathologies arising from injury to direct targeted strategies for diagnosis and intervention, which this series of integrated, bidirectional, translational studies directed towards characterizing A? processing following TBI seeks to address.

Project Summary/Abstract Affecting approximately 2 million people in the US each year, concussion or mild traumatic brain injury (mTBI) has only recently been recognized as a major health issue. This injury is by no means `mild' since it induces persisting cognitive dysfunction in many individuals. Moreover, there is increasing concern that there may be a period of vulnerability after one mTBI, during which time a second mTBI may induce greatly exaggerated pathophysiological effects. Despite the impact of mTBI, the field has only just begun to identify mechanisms, especially with regards to repetitive mTBI. Nonetheless, there is mounting evidence that traumatic axonal injury (TAI) plays an important role in single and repetitive mTBI. The goal of the proposed work is to study TAI mechanisms that are relevant to single and repetitive mTBI. This will be done using an integrated approach of in vitro experimentation with computational modeling. Our well-characterized in vitro TAI model has been used to make seminal observations identifying mechanisms of TAI that have subsequently been found in large animal and human TBI. Using this model it is proposed to examine the fundamental biomechanical thresholds that govern microtubule (MT) failure by examining the non-linear viscoelastic response to stretch injury. Since all the individual failure events cannot be accessed in situ, a quantitative ultrastructural computational model of the axon will be used to guide and interpret experimental work. Aim 1 will focus on identifying acute mechanisms of TAI failure as a function of strain and strain rate. Electron microscopy, immunofluorescence and changes in intra-axonal calcium will be used to examine mechanical breaking of MTs and unbinding of the microtubule stabilizing protein tau. A novel computational model, based on the three-dimensional ultrastructure of the axon, identify injury thresholds at the level of the whole axon and nanometer level taking into account MT-tau binding, tau diffusion and MT pretension. Aim 2 will concentrate on the spatio-temporal evolution of MT depolymerization, phosphorylation / translocation of tau and axon degeneration or recovery following TAI. The same in vitro measures from Aim 1 will be used over a temporal time course using identified injury threshold parameters. Aim 3 will examine axon vulnerability to a second injury. This vulnerability will be assessed in relation to MT stability, tau translocation and an axons ability to recover following the first injury. A strain and strain rate threshold for MT failure will be determined. A computational model following the spatiotemporal evolution of phosphorylated densities of tau, MT polymerization kinetics and stress distributions will be developed to predict vulnerability criterion based on stress, strain rate, MT length and time to a second injury. It is anticipated that the data generated will reveal biomechanical thresholds and new mechanisms of single and repetitive traumatic axonal injury that will be relevant to mild TBI in humans.

ADMINISTRATIVE CORE SUMMARY The CONNECT-TBI program represents a multidisciplinary collaboration uniting 26 internationally regarded experts in TBI and neurodegeneration across 12 leading institutions to deliver a single point of access to an unparalleled research tissue resource. To achieve this, we have developed an administrative strategy to coordinate and manage this strong collaborative team to ensure successful and timely delivery of the overall goals and all scientific, brain banking, budgetary, reporting and governance activities within CONNECT-TBI. Led by Program PIs Drs. Douglas Smith and Willie Stewart as co-directors, the Administrative Core will provide internal and external project oversight and review mechanisms against CONNECT-TBI milestones. The Administrative Core will also work to establish and coordinate tissue archiving and access procedures for external, research led enquiries, including procedures for broad and enduring institutional review and material transfer. To this end, the goals of the CONNECT-TBI Administrative Core are to, 1) Establish multidisciplinary project oversight and review via an Internal Governance Committee and External Advisory Board, with a calendar for meetings and to monitor progress against milestones, 2) Establish network governance procedures, including those to facilitate broad and enduring institutional review and material transfer agreement procedures for the CONNECT-TBI archive, 3) Create the CONNECT-TBI website to: facilitate communication on program achievements; act as the access point for enquiries and tissue applications from external researchers; and as a central and accessible repository for all CONNECT-TBI program generated protocols and 4) Coordinate management of data transfer from CONNECT-TBI to Federal Interagency TBI Research (FITBIR) Informatics system to enable access of acquired data to the broader TBI research community.

Research Project 1 SUMMARY There is growing concern over the association between traumatic brain injury (TBI) and progressive neurodegenerative changes, in particular those that are characterized as chronic traumatic encephalopathy (CTE). First recognized in boxers, it was not until descriptions of CTE pathology in non-boxer athletes attracted widespread attention. However, reflecting the paucity of cases described, current consensus criteria for the neuropathological assessment of CTE remain preliminary, with the associated clinical consequences of this pathology unclear. Furthermore, the narrow focus on CTE and its characteristic tau pathologies has come at the cost of characterizing many other neuropathologies that have also been observed in CTE cases and in all forms of TBI. Current reporting in CTE largely focuses on p-tau pathologies, which are thought to define its pathognomonic neuropathology. However, rather than a single proteinopathy, wider, unbiased autopsy reporting of TBI related neurodegeneration (TReND) in chronic TBI (cTBI) survivors across a full spectrum of injury severities documents far more varied complex neuropathologies. Furthermore, the pathologies encountered in cTBI patients often are mixed, with multiple proteinopathies, particularly in aged patients. As such, there is growing recognition that TReND in TBI survivors is a complex polypathology, just one element of which might be described by current definitions of CTE. We propose to characterize the extent, distribution and range of pathologies contributing to TReND in cTBI patients across a spectrum TBI types and severities. In addition, we will develop and validate operational criteria for the neuropathological diagnosis of TReND pathologies using established protocols that have proven successful for wider neurodegenerative disease.

OVERALL CONNECT-TBI Program Summary In the past several decades, there has been steadily increasing attention to the neuropathological effects of traumatic brain injury (TBI). Intense media attention has focused on the association of repetitive mild TBI with contact sports and have highlighted the risk of neurodegenerative changes including the widely discussed chronic traumatic encephalopathy (CTE). Unfortunately, little is known about the broader process of TBI- Related Neurodegeneration (TRenD) which encompasses a complex spectrum of pathologies induced by TBI, across all mechanisms and severity levels of injury. Arguably the greatest inhibitor of progress in this field is the limited number of suitable human brain tissue samples and their distribution among disparate research and clinical institutions. To overcome this, the proposed center without walls known as COllaborative Neuropathology NEtwork Characterizing ouTcomes of TBI (CONNECT-TBI) will be comprised of 26 leading expert investigators in TBI from 12 renowned institutions to generate an unparalleled, comprehensive neuropathological and clinical data resource and conduct a comprehensive research effort into the spectrum of pathologies in all types and severities of TBI. Three Cores ? Administrative, Brain Bank, and Data Coordinating ? will coordinate and support the collation and examination of over 2800 existing TBI case materials and over 7000 samples from patients with related neurodegenerative disorders. Furthermore, CONNECT-TBI will establish tissue donation protocols for ongoing sample enrollment in the coming years. This resource will be utilized to generate a consensus in the operational criteria for the diagnosis of TReNDs across all range and subtypes and to evaluate the extent and distribution of all neuropathologies resulting from TBI exposure. Furthermore, the center will seek to contrast the phenotypes of TReNDs with that of wider neurodegenerative disease and with aging processes. In all, the CONNECT-TBI collaboration will represent a broad, comprehensive exploration of the intricate neuropathological changes following TBI.

Research Project 3 SUMMARY There is growing concern over the association between exposure to traumatic brain injury (TBI) and increased risk of a variety of neuropsychiatric and neurocognitive outcomes, in particular those linked to participation in contact sports. Moreover, compelling epidemiological data indicates severe TBI as an important environmental risk factor for dementia with best current estimates suggesting that between 5 and 15% of all dementia may be TBI related. Both historically and currently, TBI-associated dementia has been presumptively subdivided based on whether it follows a single, moderate or severe TBI or repetitive, mild TBI. However, over the last decade, autopsy studies have revealed complex and overlapping pathologies in individuals across the spectrum of injury exposure. Critically, there is also an incomplete understanding of the extent and distribution of TBI related neurodegeneration (TReND) pathology required to produce neurological dysfunction, the spectrum of symptoms associated with this pathology, or its relationship with wider neurodegenerative disease. As such, there is a pressing need to perform unbiased, comprehensive and robust evaluations of the complete spectrum of TReND pathologies in comparison with patient associated variables and clinical outcomes. We will use comprehensive datasets of the extensive archive of case material from chronic TBI (~850 existing and the predicted additional ~450 new chronic TBI) and matched controls made possible via this CONNECT-TBI Program. Examining these unique tissue resources and linked clinical datasets offers an unrivalled opportunity to link comprehensive outcomes and assessments with neuropathological observations. We propose to 1) examine the influence of injury variables, and 2) Determine the association between neuropathological burden and antemortem clinicopathologic presentation of chronic TBI.

Research Project 2 SUMMARY There is growing concern over the association between traumatic brain injury (TBI) and progressive neurodegenerative changes, in particular those described as chronic traumatic encephalopathy (CTE). First recognized in boxers, it was not until later reports of similar pathologies in non-boxer athletes that the long-term consequences of TBI attracted widespread attention. Recent and preliminary consensus criteria propose CTE as a distinct neurodegenerative pathology, although the associated clinical consequences of this pathology remain unclear. Importantly, there is growing consensus that there is a high prevalence of comorbidity across neurodegenerative diseases including AD, Lewy body disease, and frontotemporal lobar degeneration. While, current reporting in CTE largely focuses on proposed ?pathognomonic? tau pathologies, the heterogeneity of neurodegenerative disease neuropathology associated with chronic survival from TBI (cTBI) is not well described. Here we will evaluate the spectrum of neuropathologic change that is shared or unique between TBI- related neurodegeneration (TReND) versus other neurodegenerative diseases including Alzheimer?s disease (AD), Lewy body disease, and frontotemporal lobar degeneration. Specifically, by evaluating a neurodegenerative disease autopsy cohort of 275 cases, matched to the cTBI cohort studied in research project 1, we will examine for the presence and distribution of neuropathologies including A? amyloid, tau, ?-synuclein and TDP-43 aggregates. Importantly, by examining a further cohort of 450 cases, we will also determine whether TReND pathology, like other neurodegenerative disease processes, can also be observed in neurodegenerative disease cases without any history of TBI.