scholarly journals What Can N-glycomics and N-glycoproteomics of Cerebrospinal Fluid Tell Us about Alzheimer Disease?

Biomolecules ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 858
Author(s):  
Stefan Gaunitz ◽  
Lars O. Tjernberg ◽  
Sophia Schedin-Weiss

Proteomics—large-scale studies of proteins—has over the last decade gained an enormous interest for studies aimed at revealing proteins and pathways involved in disease. To fully understand biological and pathological processes it is crucial to also include post-translational modifications in the “omics”. To this end, glycomics (identification and quantification of glycans enzymatically or chemically released from proteins) and glycoproteomics (identification and quantification of peptides/proteins with the glycans still attached) is gaining interest. The study of protein glycosylation requires a workflow that involves an array of sample preparation and analysis steps that needs to be carefully considered. Herein, we briefly touch upon important steps such as sample preparation and preconcentration, glycan release, glycan derivatization and quantification and advances in mass spectrometry that today are the work-horse for glycomics and glycoproteomics studies. Several proteins related to Alzheimer disease pathogenesis have altered protein glycosylation, and recent glycomics studies have shown differences in cerebrospinal fluid as well as in brain tissue in Alzheimer disease as compared to controls. In this review, we discuss these techniques and how they have been used to shed light on Alzheimer disease and to find glycan biomarkers in cerebrospinal fluid.

2017 ◽  
Vol 14 (4) ◽  
pp. 426-440 ◽  
Author(s):  
David Hsu ◽  
Gad A. Marshall

The field of Alzheimer disease (AD) prevention has been a culmination of basic science, clinical, and translational research. In the past three years since the new 2011 AD diagnostic guidelines, large-scale collaborative efforts have embarked on new clinical trials with the hope of someday preventing AD. This review will shed light on the historical and scientific contexts in which these trials were based on, as well as discuss potential challenges these trials may face in the coming years. Primary preventive measures, such as lifestyle, multidomain, medication, and supplemental interventions, will be analyzed. Secondary prevention as represented by disease-modifying interventions, such as antiamyloid therapy and pioglitazone, will also be reviewed. Finally, hypotheses on future directions for AD prevention trials will be proposed.


2021 ◽  
Vol 10 (11) ◽  
pp. 2358
Author(s):  
Maria Grazia Giovannini ◽  
Daniele Lana ◽  
Chiara Traini ◽  
Maria Giuliana Vannucchi

The microbiota–gut system can be thought of as a single unit that interacts with the brain via the “two-way” microbiota–gut–brain axis. Through this axis, a constant interplay mediated by the several products originating from the microbiota guarantees the physiological development and shaping of the gut and the brain. In the present review will be described the modalities through which the microbiota and gut control each other, and the main microbiota products conditioning both local and brain homeostasis. Much evidence has accumulated over the past decade in favor of a significant association between dysbiosis, neuroinflammation and neurodegeneration. Presently, the pathogenetic mechanisms triggered by molecules produced by the altered microbiota, also responsible for the onset and evolution of Alzheimer disease, will be described. Our attention will be focused on the role of astrocytes and microglia. Numerous studies have progressively demonstrated how these glial cells are important to ensure an adequate environment for neuronal activity in healthy conditions. Furthermore, it is becoming evident how both cell types can mediate the onset of neuroinflammation and lead to neurodegeneration when subjected to pathological stimuli. Based on this information, the role of the major microbiota products in shifting the activation profiles of astrocytes and microglia from a healthy to a diseased state will be discussed, focusing on Alzheimer disease pathogenesis.


Author(s):  
Lynn Marie Trotti ◽  
Donald L. Bliwise ◽  
Glenda L. Keating ◽  
David B. Rye ◽  
William T. Hu

Background/Aims: Hypocretin promotes wakefulness and modulates REM sleep. Alterations in the hypocretin system are increasingly implicated in dementia. We evaluated relationships among hypocretin, dementia biomarkers, and sleep symptoms in elderly participants, most of whom had dementia. Methods: One-hundred twenty-six adults (mean age 66.2 ± 8.4 years) were recruited from the Emory Cognitive Clinic. Diagnoses were Alzheimer disease (AD; n = 60), frontotemporal dementia (FTD; n = 21), and dementia with Lewy bodies (DLB; n = 20). We also included cognitively normal controls (n = 25). Participants and/or caregivers completed sleep questionnaires and lumbar puncture was performed for cerebrospinal fluid (CSF) assessments. Results: Except for sleepiness (worst in DLB) and nocturia (worse in DLB and FTD) sleep symptoms did not differ by diagnosis. CSF hypocretin concentrations were available for 87 participants and normal in 70, intermediate in 16, and low in 1. Hypocretin levels did not differ by diagnosis. Hypocretin levels correlated with CSF total τ levels only in men (r = 0.34; p = 0.02). Lower hypocretin levels were related to frequency of nightmares (203.9 ± 29.8 pg/mL in those with frequent nightmares vs. 240.4 ± 46.1 pg/mL in those without; p = 0.05) and vivid dreams (209.1 ± 28.3 vs. 239.5 ± 47.8 pg/mL; p = 0.014). Cholinesterase inhibitor use was not associated with nightmares or vivid dreaming. Conclusion: Hypocretin levels did not distinguish between dementia syndromes. Disturbing dreams in dementia patients may be related to lower hypocretin concentrations in CSF.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ashley A. Krull ◽  
Deborah O. Setter ◽  
Tania F. Gendron ◽  
Sybil C. L. Hrstka ◽  
Michael J. Polzin ◽  
...  

Abstract Background Mesenchymal stromal cells (MSCs) have been studied with increasing intensity as clinicians and researchers strive to understand the ability of MSCs to modulate disease progression and promote tissue regeneration. As MSCs are used for diverse applications, it is important to appreciate how specific physiological environments may stimulate changes that alter the phenotype of the cells. One need for neuroregenerative applications is to characterize the spectrum of MSC responses to the cerebrospinal fluid (CSF) environment after their injection into the intrathecal space. Mechanistic understanding of cellular biology in response to the CSF environment may predict the ability of MSCs to promote injury repair or provide neuroprotection in neurodegenerative diseases. Methods In this study, we characterized changes in morphology, metabolism, and gene expression occurring in human adipose-derived MSCs cultured in human (hCSF) or artificial CSF (aCSF) as well as examined relevant protein levels in the CSF of subjects treated with MSCs for amyotrophic lateral sclerosis (ALS). Results Our results demonstrated that, under intrathecal-like conditions, MSCs retained their morphology, though they became quiescent. Large-scale transcriptomic analysis of MSCs revealed a distinct gene expression profile for cells cultured in aCSF. The aCSF culture environment induced expression of genes related to angiogenesis and immunomodulation. In addition, MSCs in aCSF expressed genes encoding nutritional growth factors to expression levels at or above those of control cells. Furthermore, we observed a dose-dependent increase in growth factors and immunomodulatory cytokines in CSF from subjects with ALS treated intrathecally with autologous MSCs. Conclusions Overall, our results suggest that MSCs injected into the intrathecal space in ongoing clinical trials remain viable and may provide a therapeutic benefit to patients.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Daniel J. Panyard ◽  
Kyeong Mo Kim ◽  
Burcu F. Darst ◽  
Yuetiva K. Deming ◽  
Xiaoyuan Zhong ◽  
...  

AbstractThe study of metabolomics and disease has enabled the discovery of new risk factors, diagnostic markers, and drug targets. For neurological and psychiatric phenotypes, the cerebrospinal fluid (CSF) is of particular importance. However, the CSF metabolome is difficult to study on a large scale due to the relative complexity of the procedure needed to collect the fluid. Here, we present a metabolome-wide association study (MWAS), which uses genetic and metabolomic data to impute metabolites into large samples with genome-wide association summary statistics. We conduct a metabolome-wide, genome-wide association analysis with 338 CSF metabolites, identifying 16 genotype-metabolite associations (metabolite quantitative trait loci, or mQTLs). We then build prediction models for all available CSF metabolites and test for associations with 27 neurological and psychiatric phenotypes, identifying 19 significant CSF metabolite-phenotype associations. Our results demonstrate the feasibility of MWAS to study omic data in scarce sample types.


2009 ◽  
Vol 55 (12) ◽  
pp. 2171-2179 ◽  
Author(s):  
Sonia Chalbot ◽  
Henrik Zetterberg ◽  
Kaj Blennow ◽  
Tormod Fladby ◽  
Inge Grundke-Iqbal ◽  
...  

Abstract Background: The phospholipase A2 (PLA2) family comprises multiple isoenzymes that vary in their physicochemical properties, cellular localizations, calcium sensitivities, and substrate specificities. Despite these differences, PLA2s share the ability to catalyze the synthesis of the precursors of the proinflammatory mediators. To investigate the potential of PLA2 as a biomarker in screening neuroinflammatory disorders in both clinical and research settings, we developed a PLA2 assay and determined the predominant types of PLA2 activity in cerebrospinal fluid (CSF). Methods: We used liposomes composed of a fluorescent probe (bis-Bodipy® FL C11-PC [1,2-bis-(4,4- difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-undecanoyl)-sn-glycero-3-phosphocholine]) and 1,2-dioleoyl-l-α-phosphatidylcholine as a substrate to measure CSF PLA2 activity in a 96-well microtiter plate format. We established the type of CSF PLA2 activity using type-specific inhibitors of PLA2. Results: Using 5 μL CSF per assay, our PLA2 activity assay was reproducible with CVs <15% in 2 CSF samples and for recombinant secretory Ca2+-dependent PLA2 (sPLA2) in concentrations ranging from 0.25 to 1 μmol/L. This PLA2 assay allowed identification of sPLA2 activity in lumbar CSF from healthy individuals 20–77 years old that did not depend on either sex or age. Additionally, CSF sPLA2 activity was found to be increased (P = 0.0008) in patients with Alzheimer disease. Conclusions: Adult human CSF has sPLA2 activity that can be measured reliably with the assay described. This enzyme activity in the CSF is independent of both sex and age and might serve as a valuable biomarker of neuroinflammation, as we demonstrated in Alzheimer disease.


2016 ◽  
Vol 80 (3) ◽  
pp. 379-387 ◽  
Author(s):  
Andrei G. Vlassenko ◽  
Lena McCue ◽  
Mateusz S. Jasielec ◽  
Yi Su ◽  
Brian A. Gordon ◽  
...  

Author(s):  
Martin L. Rennie ◽  
Kimon Lemonidis ◽  
Connor Arkinson ◽  
Viduth K. Chaugule ◽  
Mairi Clarke ◽  
...  

AbstractThe Fanconi Anemia (FA) pathway is a dedicated pathway for the repair of DNA interstrand crosslinks, and which is additionally activated in response to other forms of replication stress. A key step in the activation of the FA pathway is the monoubiquitination of each of the two subunits (FANCI and FANCD2) of the ID2 complex on specific lysine residues. However, the molecular function of these modifications has been unknown for nearly two decades. Here we find that ubiquitination of FANCD2 acts to increase ID2’s affinity for double stranded DNA via promoting/stabilizing a large-scale conformational change in the complex, resulting in a secondary “Arm” ID2 interphase encircling DNA. Ubiquitination of FANCI, on the other hand, largely protects the ubiquitin on FANCD2 from USP1/UAF deubiquitination, with key hydrophobic residues of FANCI’s ubiquitin being important for this protection. In effect, both of these post-translational modifications function to stabilise a conformation in which the ID2 complex encircles DNA.


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