Sequestration of Muscarinic Cholinergic Receptors in Permeabilized Neuroblastoma Cells

The feasibility of using a permeabilized preparation of human SH-SY-5Y neuroblastoma cells for studies of muscarinic acetylcholine receptor (mAChR) sequestration has been evaluated. Exposure of cells permeabilized with digitonin, streptolysin-O, or the Α-toxin from Staphylococcus aureus to oxotremorine-M (Oxo-M) for 30 min resulted in a 25–30% reduction in the number of cell surface mAChRs, as monitored by the loss of N [ 3 H]methyl- scopolamine ([ 3 H]NMS) binding sites. The corresponding value for intact cells was 40%. For cells permeabilized with 20 Μ M digitonin, the Oxo-M-mediated reduction in [ 3 H]NMS binding was time ( t 1/2 ∼ 5 min) and concentration (EC 50 ∼ 10 Μ M ) dependent and was agonist specific (Oxo M > bethanechol = arecoline = pilocarpine). In contrast, no reduction in total mAChR number, as monitored by the binding of [ 3 H]quinuclidinyl benzilate, occurred following Oxo-M treatment. The loss of [ 3 H]NMS sites observed in the presence of Oxo-M was unaffected by omission of either ATP or Ca 2+ , both of which are required for stimulated phosphoinositide hydrolysis, but could be inhibited by the inclusion of guanosine 5′- O -(2-thiodiphosphate). mAChRs sequestered in response to Oxo-M addition were unmasked when the cells were permeabilized in the presence of higher concentrations of digitonin (80 Μ M ). The results indicate (a) that permeabilized SH-SY-5Y cells support an agonist-induced sequestration of mAChRs, the magnitude of which is ∼ 65–70% of that observed for intact cells, (b) that when internalized, mAChRs are located in a cellular compartment to which [ 3 H]NMS has only a limited access despite the removal of the plasma membrane barrier, and (c) that the production of phosphoinositide-derived second messengers is not a prerequisite for mAChR sequestration.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65736/1/j.1471-4159.1994.62051795.x.pd

Proteomic Analysis of Hippocampal Dentate Granule Cells in Frontotemporal Lobar Degeneration: Application of Laser Capture Technology

Frontotemporal lobar degeneration (FTLD) is the most common cause of dementia with pre-senile onset, accounting for as many as 20% of cases. A common subset of FTLD cases is characterized by the presence of ubiquitinated inclusions in vulnerable neurons (FTLD-U). While the pathophysiological mechanisms underlying neurodegeneration in FTLD-U have not yet been elucidated, the presence of inclusions in this disease indicates enhanced aggregation of one or several proteins. Moreover, these inclusions suggest altered expression, processing, or degradation of proteins during FTLD-U pathogenesis. Thus, one approach to understanding disease mechanisms is to delineate the molecular changes in protein composition in FTLD-U brain. Using a combined approach consisting of laser capture microdissection (LCM) and high-resolution liquid chromatography-tandem mass spectrometry (LC–MS/MS), we identified 1252 proteins in hippocampal dentate granule cells excised from three post-mortem FTLD-U and three unaffected control cases processed in parallel. Additionally, we employed a labeling-free quantification technique to compare the abundance of the identified proteins between FTLD-U and control cases. Quantification revealed 54 proteins with selective enrichment in FTLD-U, including TAR–DNA binding protein 43 (TDP-43), a recently identified component of ubiquitinated inclusions. Moreover, 19 proteins were selectively decreased in FTLD-U. Subsequent immunohistochemical analysis of TDP-43 and three additional protein candidates suggests that our proteomic profiling of FTLD-U dentate granule cells reveals both inclusion-associated proteins and non-aggregated disease-specific proteins. Application of LCM is a valuable tool in the molecular analysis of complex tissues, and its application in the proteomic characterization of neurodegenerative disorders such as FTLD-U may be used to identify proteins altered in disease

Localization of muscarinic M3 receptor protein and M3 receptor binding in rat brain

A family of receptor subtypes, defined either by molecular (ml-m5) or pharmacological (M1-M4) analysis, mediates muscarinic cholinergic neurotransmission in brain. The distribution and functions of the m3 receptor protein in brain and its relation to M3 ligand binding sites are poorly understood. To better characterize the native brain receptors, subtype-specific antibodies reactive with the putative third inner loops were used: (i) to measure the abundance of m3 protein and its regional distribution in rat brain by immunoprecipitation; (ii) to determine the cellular and subcellular distribution of m3 protein by light microscopic immunocytochemistry; and (iii) to compare the distribution of m3 immunoreactivity with the autoradiographic distribution of M3 binding sites labeled by [3H]4-diphenylacetoxy-N-methyl pipericline methioxide in the presence of antagonists selective for the other receptor binding sites. The m3 protein, measured by immunoprecipitation, accounted for 5-10% of total solubilized receptors in all brain regions studied. Immunocytochemistry also revealed a widespread distribution of m3-like immunoreactivity, and localized the subtype to discrete neuronal populations and distinct subcellular compartments. The distribution of m3 protein was consistent with the messenger RNA expression, and like M3 binding sites, the protein was enriched in limbic cortical regions, striatum, hippocompus, anterior thalamic nuclei, superior colliculus and pontine nuclei. However, m3 immunoreactivity and M3 binding were differentially localized in regions and lamina of cortex and hippocompus.The results confirm the presence of m3 protein in brain, its low abundance compared to other muscarinic receptor subtypes, and provide the first immunocytochemical map of its precise localization. The distribution of m3 suggests that it mediates a wide variety of cholinergic processes in brain, inclucling possible roles in learning and memory, motor function and behavioral state control. However, since the distribution of the molecularly-defined receptor protein is distinct from the pharmacologically-defined M3 binding site, investigations of the functions of m3 in brain must await development of more selective ligands or use of non-pharmacological approaches.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31207/1/0000109.pd

Molecules of senescent glial cells differentiate Alzheimer's disease from ageing

BACKGROUND: Ageing is a major risk factor for Alzheimer's disease (AD), which is accompanied by cellular senescence and thousands of transcriptional changes in the brain. OBJECTIVES: To identify the biomarkers in the cerebrospinal fluid (CSF) that could help differentiate healthy ageing from neurodegenerative processes. METHODS: Cellular senescence and ageing-related biomarkers were assessed in primary astrocytes and postmortem brains by immunoblotting and immunohistochemistry. The biomarkers were measured in CSF samples from the China Ageing and Neurodegenerative Disorder Initiative cohort using Elisa and the multiplex Luminex platform. RESULTS: The cyclin-dependent kinase inhibitors p16/p21-positive senescent cells in human postmortem brains were predominantly astrocytes and oligodendrocyte lineage cells, which accumulated in AD brains. CCL2, YKL-40, HGF, MIF, S100B, TSP2, LCN2 and serpinA3 are biomarkers closely related to human glial senescence. Moreover, we discovered that most of these molecules, which were upregulated in senescent glial cells, were significantly elevated in the AD brain. Notably, CSF YKL-40 (β=0.5412, p<0.0001) levels were markedly elevated with age in healthy older individuals, whereas HGF (β=0.2732, p=0.0001), MIF (β=0.33714, p=0.0017) and TSP2 (β=0.1996, p=0.0297) levels were more susceptible to age in older individuals with AD pathology. We revealed that YKL-40, TSP2 and serpinA3 were useful biomarkers for discriminating patients with AD from CN individuals and non-AD patients. DISCUSSION: Our findings demonstrated the different patterns of CSF biomarkers related to senescent glial cells between normal ageing and AD, implicating these biomarkers could identify the road node in healthy path off to neurodegeneration and improve the accuracy of clinical AD diagnosis, which would help promote healthy ageing

A Feasibility Study on Indoor Localization and Multi-person Tracking Using Sparsely Distributed Camera Network with Edge Computing

Camera-based activity monitoring systems are becoming an attractive solution for smart building applications with the advances in computer vision and edge computing technologies. In this paper, we present a feasibility study and systematic analysis of a camera-based indoor localization and multi-person tracking system implemented on edge computing devices within a large indoor space. To this end, we deployed an end-to-end edge computing pipeline that utilizes multiple cameras to achieve localization, body orientation estimation and tracking of multiple individuals within a large therapeutic space spanning $1700m^2$, all while maintaining a strong focus on preserving privacy. Our pipeline consists of 39 edge computing camera systems equipped with Tensor Processing Units (TPUs) placed in the indoor space's ceiling. To ensure the privacy of individuals, a real-time multi-person pose estimation algorithm runs on the TPU of the computing camera system. This algorithm extracts poses and bounding boxes, which are utilized for indoor localization, body orientation estimation, and multi-person tracking. Our pipeline demonstrated an average localization error of 1.41 meters, a multiple-object tracking accuracy score of 88.6\%, and a mean absolute body orientation error of 29\degree. These results shows that localization and tracking of individuals in a large indoor space is feasible even with the privacy constrains

Development of a Rapid Screening Instrument for Mild Cognitive Impairment and Undiagnosed Dementia

Mild cognitive impairment (MCI) often presages development of Alzheimer’s disease (AD). We recently completed a cross-sectional study to test the hypothesis that a combination of a brief cognitive screening instrument (Mini-Cog) with a functional scale (Functional Activities Questionnaire; FAQ) would accurately identify individuals with MCI and undiagnosed dementia. The Mini-Cog consists of a clock drawing task and 3-item recall, and takes less than 5 minutes to administer. The FAQ is a 30-item questionnaire completed by an informant. In addition to the Mini-Cog and FAQ, a traditional cognitive test battery was administered, and two neurologists and a neuropsychologist determined a consensus diagnosis of Normal, MCI, or Dementia. A classification tree algorithm was used to pick optimal cutpoints, and, using these cutpoints, the combined Mini-Cog and FAQ (MC-FAQ) predicted the consensus diagnosis with an accuracy of 83% and a weighted kappa of 0.81. When the population was divided into Normal and Abnormal, the sensitivity, specificity and positive predictive value were 89%, 90%, and 95%, respectively. The MC-FAQ discriminates individuals with MCI from cognitively normal individuals and those with dementia, and its ease of administration makes it an attractive screening instrument to aid detection of cognitive impairment in the elderly

Familial Parkinson's Disease-associated L166P Mutation Disrupts DJ-1 Protein Folding and Function

Mutations in DJ-1, a protein of unknown function, were recently identified as the cause for an autosomal recessive, early onset form of familial Parkinson's disease. Here we report that DJ-1 is a dimeric protein that exhibits protease activity but no chaperone activity. The protease activity was abolished by mutation of Cys-106 to Ala, suggesting that DJ-1 functions as a cysteine protease. Our studies revealed that the Parkinson's disease-linked L166P mutation impaired the intrinsic folding propensity of DJ-1 protein, resulting in a spontaneously unfolded structure that was incapable of forming a homodimer with itself or a heterodimer with wild-type DJ-1. Correlating with the disruption of DJ-1 structure, the L166P mutation abolished the catalytic function of DJ-1. Furthermore, as a result of protein misfolding, the L166P mutant DJ-1 was selectively polyubiquitinated and rapidly degraded by the proteasome. Together these findings provide insights into the molecular mechanism by which loss-of-function mutations in DJ-1 lead to Parkinson's disease

Open drug discovery in Alzheimer\u27s disease.

Alzheimer\u27s disease (AD) drug discovery has focused on a set of highly studied therapeutic hypotheses, with limited success. The heterogeneous nature of AD processes suggests that a more diverse, systems-integrated strategy may identify new therapeutic hypotheses. Although many target hypotheses have arisen from systems-level modeling of human disease, in practice and for many reasons, it has proven challenging to translate them into drug discovery pipelines. First, many hypotheses implicate protein targets and/or biological mechanisms that are under-studied, meaning there is a paucity of evidence to inform experimental strategies as well as high-quality reagents to perform them. Second, systems-level targets are predicted to act in concert, requiring adaptations in how we characterize new drug targets. Here we posit that the development and open distribution of high-quality experimental reagents and informatic outputs-termed target enabling packages (TEPs)-will catalyze rapid evaluation of emerging systems-integrated targets in AD by enabling parallel, independent, and unencumbered research

Large-scale proteomic analysis of human brain identifies proteins associated with cognitive trajectory in advanced age

In advanced age, some individuals maintain a stable cognitive trajectory while others experience a rapid decline. Such variation in cognitive trajectory is only partially explained by traditional neurodegenerative pathologies. Hence, to identify new processes underlying variation in cognitive trajectory, we perform an unbiased proteome-wide association study of cognitive trajectory in a discovery (n = 104) and replication cohort (n = 39) of initially cognitively unimpaired, longitudinally assessed older-adult brain donors. We find 579 proteins associated with cognitive trajectory after meta-analysis. Notably, we present evidence for increased neuronal mitochondrial activities in cognitive stability regardless of the burden of traditional neuropathologies. Furthermore, we provide additional evidence for increased synaptic abundance and decreased inflammation and apoptosis in cognitive stability. Importantly, we nominate proteins associated with cognitive trajectory, particularly the 38 proteins that act independently of neuropathologies and are also hub proteins of protein co-expression networks, as promising targets for future mechanistic studies of cognitive trajectory.Accelerating Medicine Partnership for AD [U01AG046161, U01 AG061357]; Emory Alzheimer's Disease Research Center [P50 AG025688]; NINDS Emory Neuroscience Core [P30 NS055077]; intramural program of the National Institute on Aging (NIA); Alzheimer's Association; Alzheimer's Research UK; Michael J. Fox Foundation for Parkinson's Research; Weston Brain Institute Biomarkers Across Neurodegenerative Diseases Grant [11060]; National Institute of Neurological Disorders and Stroke [U24 NS072026]; National Institute on Aging [P30 AG19610]; Arizona Department of Health Services [211002]; Arizona Biomedical Research Commission [4001, 0011, 05-901, 1001]; [R01 AG056533]; [R01 AG053960]; [U01 MH115484]; [I01 BX003853]; [IK2 BX001820]; [R01 AG061800]; [R01 AG057911]Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]