Cerebrospinal fluid neurogranin concentration in neurodegeneration: relation to clinical phenotypes and neuropathology

Neurogranin (Ng) is a post-synaptic protein that previously has been shown to be a biomarker for synaptic function when measured in cerebrospinal fluid (CSF). The CSF concentration of Ng is increased in Alzheimer's disease dementia (ADD), and even in the pre-dementia stage. In this prospective study, we used an enzyme-linked immunosorbent assay that quantifies Ng in CSF to test the performance of Ng as a marker of synaptic function. In 915 patients, CSF Ng was evaluated across several different neurodegenerative diseases. Of these 915 patients, 116 had a neuropathologically confirmed definitive diagnosis and the relation between CSF Ng and topographical distribution of different pathologies in the brain was evaluated. CSF Ng was specifically increased in ADD compared to eight other neurodegenerative diseases, including Parkinson's disease (p < 0.0001), frontotemporal dementia (p < 0.0001), and amyotrophic lateral sclerosis (p = 0.0002). Similar results were obtained in neuropathologically confirmed cases. Using a biomarker index to evaluate whether CSF Ng contributed diagnostic information to the core AD CSF biomarkers (amyloid β (Aβ), t-tau, and p-tau), we show that Ng significantly increased the discrimination between AD and several other disorders. Higher CSF Ng levels were positively associated with greater Aβ neuritic plaque (Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuritic plaque score, p = 0.0002) and tau tangle pathology (Braak neurofibrillary tangles staging, p = 0.0007) scores. In the hippocampus and amygdala, two brain regions heavily affected in ADD with high expression of Ng, CSF Ng was associated with plaque (p = 0.0006 and p < 0.0001), but not with tangle, α-synuclein, or TAR DNA-binding protein 43 loads. These data support that CSF Ng is increased specifically in ADD, that high CSF Ng concentrations likely reflect synaptic dysfunction and that CSF Ng is associated with β-amyloid plaque pathology

Elevated CSF GAP-43 is Alzheimer's disease specific and associated with tau and amyloid pathology

Introduction: The level of the presynaptic protein growth-associated protein 43 (GAP-43) in cerebrospinal fluid (CSF) has previously been shown to be increased in Alzheimer's disease (AD) and thus may serve as an outcome measure in clinical trials and facilitate earlier disease detection. / Methods: We developed an enzyme-linked immunosorbent assay for CSF GAP-43 and measured healthy controls (n = 43), patients with AD (n = 275), or patients with other neurodegenerative diseases (n = 344). In a subpopulation (n = 93), CSF GAP-43 concentrations from neuropathologically confirmed cases were related to Aβ plaques, tau, α-synuclein, and TDP-43 pathologies. / Results: GAP-43 was significantly increased in AD compared to controls and most neurodegenerative diseases and correlated with the magnitude of neurofibrillary tangles and Aβ plaques in the hippocampus, amygdala, and cortex. GAP-43 was not associated to α-synuclein or TDP-43 pathology. / Discussion: The presynaptic marker GAP-43 is associated with both diagnosis and neuropathology of AD and thus may be useful as a sensitive and specific biomarker for clinical research

Rapid selection of cyclic peptides that reduce alpha-synuclein toxicity in yeast and animal models

Phage display has demonstrated the utility of cyclic peptides as general protein ligands but cannot access proteins inside eukaryotic cells. Expanding a new chemical genetics tool, we describe the first expressed library of head-to-tail cyclic peptides in yeast (Saccharomyces cerevisiae). We applied the library to selections in a yeast model of alpha-synuclein toxicity that recapitulates much of the cellular pathology of Parkinson's disease. From a pool of 5 million transformants, we isolated two related cyclic peptide constructs that specifically reduced the toxicity of human alpha-synuclein. These expressed cyclic peptide constructs also prevented dopaminergic neuron loss in an established Caenorhabditis elegans Parkinson's model. This work highlights the speed and efficiency of using libraries of expressed cyclic peptides for forward chemical genetics in cellular models of human disease

Evaluation of the brain-penetrant microtubule-stabilizing agent, dictyostatin, in the PS19 tau transgenic mouse model of tauopathy

Neurodegenerative disorders referred to as tauopathies, which includes Alzheimer's disease (AD), are characterized by insoluble deposits of the tau protein within neuron cell bodies and dendritic processes in the brain. Tau is normally associated with microtubules (MTs) in axons, where it provides MT stabilization and may modulate axonal transport. However, tau becomes hyperphosphorylated and dissociates from MTs in tauopathies, with evidence of reduced MT stability and defective axonal transport. This has led to the hypothesis that MT-stabilizing drugs may have potential for the treatment of tauopathies. Prior studies demonstrated that the brain-penetrant MT-stabilizing drug, epothilone D, had salutary effects in transgenic (Tg) mouse models of tauopathy, improving MT density and axonal transport, while reducing axonal dystrophy. Moreover, epothilone D enhanced cognitive performance and decreased hippocampal neuron loss, with evidence of reduced tau pathology. To date, epothilone D has been the only non-peptide small molecule MT-stabilizing agent to be evaluated in Tg tau mice. Herein, we demonstrate the efficacy of another small molecule brain-penetrant MT-stabilizing agent, dictyostatin, in the PS19 tau Tg mouse model. Although dictyostatin was poorly tolerated at once-weekly doses of 1 mg/kg or 0.3 mg/kg, likely due to gastrointestinal (GI) complications, a dictyostatin dose of 0.1 mg/kg was better tolerated, such that the majority of 6-month old PS19 mice, which harbor a moderate level of brain tau pathology, completed a 3-month dosing study without evidence of significant body weight loss. Importantly, as previously observed with epothilone D, the dictyostatin-treated PS19 mice displayed improved MT density and reduced axonal dystrophy, with a reduction of tau pathology and a trend toward increased hippocampal neuron survival relative to vehicle-treated PS19 mice. Thus, despite evidence of dose-limiting peripheral side effects, the observed positive brain outcomes in dictyostatin-treated aged PS19 mice reinforces the concept that MT-stabilizing compounds have significant potential for the treatment of tauopathies

Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium

The Dementia with Lewy Bodies (DLB) Consortium has refined its recommendations about the clinical and pathologic diagnosis of DLB, updating the previous report, which has been in widespread use for the last decade. The revised DLB consensus criteria now distinguish clearly between clinical features and diagnostic biomarkers, and give guidance about optimal methods to establish and interpret these. Substantial new information has been incorporated about previously reported aspects of DLB, with increased diagnostic weighting given to REM sleep behavior disorder and $^{123}$iodine-metaiodobenzylguanidine (MIBG) myocardial scintigraphy. The diagnostic role of other neuroimaging, electrophysiologic, and laboratory investigations is also described. Minor modifications to pathologic methods and criteria are recommended to take account of Alzheimer disease neuropathologic change, to add previously omitted Lewy-related pathology categories, and to include assessments for substantia nigra neuronal loss. Recommendations about clinical management are largely based upon expert opinion since randomized controlled trials in DLB are few. Substantial progress has been made since the previous report in the detection and recognition of DLB as a common and important clinical disorder. During that period it has been incorporated into DSM-5, as major neurocognitive disorder with Lewy bodies. There remains a pressing need to understand the underlying neurobiology and pathophysiology of DLB, to develop and deliver clinical trials with both symptomatic and disease-modifying agents, and to help patients and carers worldwide to inform themselves about the disease, its prognosis, best available treatments, ongoing research, and how to get adequate support.The DLB Consortium meeting was organized by the Mayo School of Continuous Professional Development (MSCPD) and supported by Acadia Pharmaceuticals, Alzheimer’s Association, Axovant Sciences, Banner Health, GE Healthcare, the Lewy Body Dementia Association, the Lewy Body Society, Lundbeck, the National Institute on Aging, the National Institute on Neurologic Disease and Stroke, and an NIH grant (R13 NS095618). Kathy Fuqua, Julie Reed, and colleagues at the MSCPD provided administrative support to the consortium meeting in Fort Lauderdale. I.G.M., D.B., J.-P.T., J.A., and A.T. receive support from the UK NIHR Biomedical Research Centre awarded to the Newcastle upon Tyne Hospitals NHS Foundation Trust and Newcastle University. Travel grant support was provided by the Alzheimer’s Research UK ARUK NE Network Centre. B.F.B., D.W.D., K.K., and T.J.F. are supported by the NIH (P50-AG016574) and the Mangurian Foundation for Lewy Body Research. G.H. is a senior principal research fellowship holder from the National Health and Medical Research Council of Australia (1079679). D.A. is a Royal Society Wolfson Research Merit Award Holder and thanks the Wolfson Foundation and the Royal Society for their support. C.G.B. thanks the Maudsley BRC for Mental Health and BRU dementia for supporting his involvement in the work. A.C.-P. receives research support from the NIH (RO1 NS082265, UO1 NS082134, P50 NS053488), the Burroughs Wellcome Fund, the Alzheimer’s Association/Michael J. Fox Foundation/Weston Biomarkers Across Neurodegenerative Disease initiative, and the Pechenik Montague Award Fund. D.f. acknowledges support from NIHR Programme Grants for Applied Research (RP-PG-0610-10100 SHAPED). O.E.-A. acknowledges support for OE laboratory from the Michael J. Fox Foundation for Parkinson’s Research (New York). S.N.G. receives support from R21 NS 090243 and the National Parkinson’s Foundation. O.A.R. is supported through the Mayo Clinic: A Morris K. Udall Parkinson’s Disease Research Center of Excellence (NINDS P50 NS072187), NINDS R01 NS078086, the Michael J. Fox Foundation for Parkinson’s Research, the Mayo Clinic AD and Related Dementias Genetics Program, and The Little Family Foundation. A.S.’s work is supported by the Intramural Research Program of the National Institute on Aging, Department of Health and Human Services. D.T. acknowledges the work of Cyrus Zabetian, MD, and Ignacio Mata, PhD, from VA Puget Sound Health Care System. J.Q.T. and V.M.Y.L.’s contributions were supported in part by a P50 NS053488 Morris K. Udall Parkinson’s Disease Research Center of Excellence grant from NINDS. P.T. acknowledges support from the Italian Ministry of Health “Ricerca Corrente.” M.Y. acknowledges support from the Japan Foundation for Neuroscience and Mental Health

Coordinate reduction in cell proliferation and cell death in mouse olfactory epithelium from birth to maturity

We investigated cell proliferation and cell death in the olfactory epithelium (OE) of mice from birth to maturity using bromodeoxyuridine and terminal deoxynucleotidyl transferase nick end labeling. We show that cell death events and proliferative activity diminish concomitantly with age in the OE. Thus, the age-dependent and coordinate diminution in cell proliferative activity and cell death events may serve to maintain the thickness of the OE as mice mature and age. (C) 1997 Elsevier Science B.V

NERVE GROWTH-FACTOR RECEPTOR EXPRESSION IN PERIPHERAL AND CENTRAL NEUROECTODERMAL TUMORS, OTHER PEDIATRIC BRAIN-TUMORS, AND DURING DEVELOPMENT OF THE ADRENAL-GLAND

Nerve growth factor (NGF) is important to the survival, development, and differentiation of neurons. Its action is mediated by a specific cell surface transmembrane glycoprotein, nerve growth factor receptor (NGFR). In this study, NGFR expression by human fetal and adult adrenal medullary tissue, peripheral nervous system (PNS) neuroectodermal tumors (neuroblastoma, ganglioneuroblastoma, ganglioneuroma), pediatric primitive neuroectodermal tumors (PNETs) of the central nervous system (CNS), and CNS gliomas was examined by an immunohistochemical technique. Sixty-nine tumors in total were probed in this manner. Nerve growth factor receptor immunoreactivity was confined to nerve fibers and clusters of primitive-appearing cells in the fetal adrenal, and to nerve fibers and ganglion cells of the adult adrenal medulla; adrenal chromaffin cells were negative. In PNS neuroectodermal tumors, there was NGFR expression in tumor cells of 6 of 11 neuroblastomas and 6 of 6 ganglioneuroblastomas or ganglioneuromas. Thirteen of thirty-five CNS PNETs showed NGFR positivity. In most CNS PNETs, NGFR was restricted to scattered single or small groups of cells, but two tumors with astroglial differentiation showed much more extensive immunoreactivity. Most astrocytomas (11 of 14) and all ependymomas (3 of 3) were intensely NGFR positive

Mechanism of Ca 2+ Disruption in Alzheimer's Disease by Presenilin Regulation of InsP 3 Receptor Channel Gating

Mutations in presenilins (PS) are the major cause of familial Alzheimer's disease (FAD) and have been associated with calcium (Ca 2+) signaling abnormalities. Here, we demonstrate that FAD mutant PS1 (M146L) and PS2 (N141I) interact with the inositol 1,4,5-trisphosphate receptor (InsP 3R) Ca 2+ release channel and exert profound stimulatory effects on its gating activity in response to saturating and suboptimal levels of InsP 3. These interactions result in exaggerated cellular Ca 2+ signaling in response to agonist stimulation as well as enhanced low-level Ca 2+ signaling in unstimulated cells. Parallel studies in InsP 3R-expressing and -deficient cells revealed that enhanced Ca 2+ release from the endoplasmic reticulum as a result of the specific interaction of PS1-M146L with the InsP 3R stimulates amyloid beta processing, an important feature of AD pathology. These observations provide molecular insights into the "Ca 2+ dysregulation" hypothesis of AD pathogenesis and suggest novel targets for therapeutic intervention. © 2008 Elsevier Inc. All rights reserved.link_to_subscribed_fulltex