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Publications in Health Sciences by NOMIS researchers

Spatial proteomics in three-dimensional intact specimens

NOMIS Researcher(s)

Published in

December 22, 2022

Spatial molecular profiling of complex tissues is essential to investigate cellular function in physiological and pathological states. However, methods for molecular analysis of large biological specimens imaged in 3D are lacking. Here, we present DISCO-MS, a technology that combines whole-organ/whole-organism clearing and imaging, deep-learning-based image analysis, robotic tissue extraction, and ultra-high-sensitivity mass spectrometry. DISCO-MS yielded proteome data indistinguishable from uncleared samples in both rodent and human tissues. We used DISCO-MS to investigate microglia activation along axonal tracts after brain injury and characterized early- and late-stage individual amyloid-beta plaques in a mouse model of Alzheimer’s disease. DISCO-bot robotic sample extraction enabled us to study the regional heterogeneity of immune cells in intact mouse bodies and aortic plaques in a complete human heart. DISCO-MS enables unbiased proteome analysis of preclinical and clinical tissues after unbiased imaging of entire specimens in 3D, identifying diagnostic and therapeutic opportunities for complex diseases. Video abstract: [Figure presented]

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1016/j.cell.2022.11.021

On the realness of people who do not exist: The social processing of artificial faces

NOMIS Researcher(s)

Published in

December 22, 2022

Today more than ever, we are asked to evaluate the realness, truthfulness and trustworthiness of our social world. Here, we focus on how people evaluate realistic-looking faces of non-existing people generated by generative adversarial networks (GANs). GANs are increasingly used in marketing, journalism, social media, and political propaganda. In three studies, we investigated if and how participants can distinguish between GAN and REAL faces and the social consequences of their exposure to artificial faces. GAN faces were more likely to be perceived as real than REAL faces, a pattern partly explained by intrinsic stimulus characteristics. Moreover, participants’ realness judgments influenced their behavior because they displayed increased social conformity toward faces perceived as real, independently of their actual realness. Lastly, knowledge about the presence of GAN faces eroded social trust. Our findings point to potentially far-reaching consequences for the pervasive use of GAN faces in a culture powered by images at unprecedented levels.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1016/j.isci.2022.105441

Cerebrospinal fluid immune dysregulation during healthy brain aging and cognitive impairment

NOMIS Researcher(s)

Published in

December 22, 2022

Cerebrospinal fluid (CSF) contains a tightly regulated immune system. However, knowledge is lacking about how CSF immunity is altered with aging or neurodegenerative disease. Here, we performed single-cell RNA sequencing on CSF from 45 cognitively normal subjects ranging from 54 to 82 years old. We uncovered an upregulation of lipid transport genes in monocytes with age. We then compared this cohort with 14 cognitively impaired subjects. In cognitively impaired subjects, downregulation of lipid transport genes in monocytes occurred concomitantly with altered cytokine signaling to CD8 T cells. Clonal CD8 T effector memory cells upregulated C-X-C motif chemokine receptor 6 (CXCR6) in cognitively impaired subjects. The CXCR6 ligand, C-X-C motif chemokine ligand 16 (CXCL16), was elevated in the CSF of cognitively impaired subjects, suggesting CXCL16-CXCR6 signaling as a mechanism for antigen-specific T cell entry into the brain. Cumulatively, these results reveal cerebrospinal fluid immune dysregulation during healthy brain aging and cognitive impairment.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1016/j.cell.2022.11.019

Actin cytoskeleton and complex cell architecture in an Asgard archaeon

NOMIS Researcher(s)

Published in

December 21, 2022

Asgard archaea are considered to be the closest known relatives of eukaryotes. Their genomes contain hundreds of eukaryotic signature proteins (ESPs), which inspired hypotheses on the evolution of the eukaryotic cell1–3. A role of ESPs in the formation of an elaborate cytoskeleton and complex cellular structures has been postulated4–6, but never visualized. Here we describe a highly enriched culture of ‘Candidatus Lokiarchaeum ossiferum’, a member of the Asgard phylum, which thrives anaerobically at 20 °C on organic carbon sources. It divides every 7–14 days, reaches cell densities of up to 5 × 107 cells per ml and has a significantly larger genome compared with the single previously cultivated Asgard strain7. ESPs represent 5% of its protein-coding genes, including four actin homologues. We imaged the enrichment culture using cryo-electron tomography, identifying ‘Ca. L. ossiferum’ cells on the basis of characteristic expansion segments of their ribosomes. Cells exhibited coccoid cell bodies and a network of branched protrusions with frequent constrictions. The cell envelope consists of a single membrane and complex surface structures. A long-range cytoskeleton extends throughout the cell bodies, protrusions and constrictions. The twisted double-stranded architecture of the filaments is consistent with F-actin. Immunostaining indicates that the filaments comprise Lokiactin—one of the most highly conserved ESPs in Asgard archaea. We propose that a complex actin-based cytoskeleton predated the emergence of the first eukaryotes and was a crucial feature in the evolution of the Asgard phylum by scaffolding elaborate cellular structures. © 2022, The Author(s).

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1038/s41586-022-05550-y

FXR mediates ILC-intrinsic responses to intestinal inflammation

NOMIS Researcher(s)

Published in

December 20, 2022

The pleiotropic actions of the Farnesoid X Receptor (FXR) are required for gut health, and reciprocally, reduced intestinal FXR signaling is seen in inflammatory bowel diseases (IBDs). Here, we show that activation of FXR selectively in the intestine is protective in inflammation-driven models of IBD. Prophylactic activation of FXR restored homeostatic levels of pro-inflammatory cytokines, most notably IL17. Importantly, these changes were attributed to FXR regulation of innate lymphoid cells (ILCs), with both the inflammation-driven increases in ILCs, and ILC3s in particular, and the induction of Il17a and Il17f in ILC3s blocked by FXR activation. Moreover, a population of ILC precursor-like cells increased with treatment, implicating FXR in the maturation/ differentiation of ILC precursors. These findings identify FXR as an intrinsic regulator of intestinal ILCs and a potential therapeutic target in inflammatory intestinal diseases.

Research field(s)
Health Sciences, Clinical Medicine, Immunology

DOI
10.1073/pnas.2213041119

Adaptable toolbox to characterize Alzheimer’s disease pathology in mouse models

NOMIS Researcher(s)

Published in

December 16, 2022

Here, we describe a highly adaptable toolbox for characterizing and analyzing molecular and histopathological changes in Alzheimer’s disease (AD) mouse models. We detail optimized and streamlined approaches from sample preparation to image analysis to facilitate reproducible analyses. We also describe the extraction and measurement of the soluble Aβ level by sandwich ELISA in the cortex and hippocampus of AD mouse models before and after plaque deposition. Finally, we outline the steps for image quantification and analysis using Imaris and ImageJ. For complete details on the use and execution of this protocol, please refer to Huang et al. (2021).1

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1016/j.xpro.2022.101891

LATE-NC staging in routine neuropathologic diagnosis: an update

NOMIS Researcher(s)

Published in

December 13, 2022

An international consensus report in 2019 recommended a classification system for limbic-predominant age-related TDP-43 encephalopathy neuropathologic changes (LATE-NC). The suggested neuropathologic staging system and nomenclature have proven useful for autopsy practice and dementia research. However, some issues remain unresolved, such as cases with unusual features that do not fit with current diagnostic categories. The goal of this report is to update the neuropathologic criteria for the diagnosis and staging of LATE-NC, based primarily on published data. We provide practical suggestions about how to integrate available genetic information and comorbid pathologies [e.g., Alzheimer’s disease neuropathologic changes (ADNC) and Lewy body disease]. We also describe recent research findings that have enabled more precise guidance on how to differentiate LATE-NC from other subtypes of TDP-43 pathology [e.g., frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS)], and how to render diagnoses in unusual situations in which TDP-43 pathology does not follow the staging scheme proposed in 2019. Specific recommendations are also made on when not to apply this diagnostic term based on current knowledge. Neuroanatomical regions of interest in LATE-NC are described in detail and the implications for TDP-43 immunohistochemical results are specified more precisely. We also highlight questions that remain unresolved and areas needing additional study. In summary, the current work lays out a number of recommendations to improve the precision of LATE-NC staging based on published reports and diagnostic experience. © 2022, The Author(s).

Research field(s)
Health Sciences

DOI
10.1007/s00401-022-02524-2

The sound of swearing: Are there universal patterns in profanity?

NOMIS Researcher(s)

Published in

December 6, 2022

Why do swear words sound the way they do? Swear words are often thought to have sounds that render them especially fit for purpose, facilitating the expression of emotion and attitude. To date, however, there has been no systematic cross-linguistic investigation of phonetic patterns in profanity. In an initial, pilot study we explored statistical regularities in the sounds of swear words across a range of typologically distant languages. The best candidate for a cross-linguistic phonemic pattern in profanity was the absence of approximants (sonorous sounds like l, r, w and y). In Study 1, native speakers of various languages (Arabic, Chinese, Finnish, French, German, Spanish; N = 215) judged foreign words less likely to be swear words if they contained an approximant. In Study 2 we found that sanitized versions of English swear words – like darn instead of damn – contain significantly more approximants than the original swear words. Our findings reveal that not all sounds are equally suitable for profanity, and demonstrate that sound symbolism – wherein certain sounds are intrinsically associated with certain meanings – is more pervasive than has previously been appreciated, extending beyond denoting single concepts to serving pragmatic functions.

Research field(s)
Health Sciences, Psychology & Cognitive Sciences, Experimental Psychology

DOI
10.3758/s13423-022-02202-0

Recursive Editing improves homology-directed repair through retargeting of undesired outcomes

NOMIS Researcher(s)

Published in

December 1, 2022

CRISPR-Cas induced homology-directed repair (HDR) enables the installation of a broad range of precise genomic modifications from an exogenous donor template. However, applications of HDR in human cells are often hampered by poor efficiency, stemming from a preference for error-prone end joining pathways that yield short insertions and deletions. Here, we describe Recursive Editing, an HDR improvement strategy that selectively retargets undesired indel outcomes to create additional opportunities to produce the desired HDR allele. We introduce a software tool, named REtarget, that enables the rational design of Recursive Editing experiments. Using REtarget-designed guide RNAs in single editing reactions, Recursive Editing can simultaneously boost HDR efficiencies and reduce undesired indels. We also harness REtarget to generate databases for particularly effective Recursive Editing sites across the genome, to endogenously tag proteins, and to target pathogenic mutations. Recursive Editing constitutes an easy-to-use approach without potentially deleterious cell manipulations and little added experimental burden.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1038/s41467-022-31944-7

Methods to investigate intrathecal adaptive immunity in neurodegeneration

NOMIS Researcher(s)

Published in

December 1, 2022

Background: Cerebrospinal fluid (CSF) provides basic mechanical and immunological protection to the brain. Historically, analysis of CSF has focused on protein changes, yet recent studies have shed light on cellular alterations. Evidence now exists for involvement of intrathecal T cells in the pathobiology of neurodegenerative diseases. However, a standardized method for long-term preservation of CSF immune cells is lacking. Further, the functional role of CSF T cells and their cognate antigens in neurodegenerative diseases are largely unknown. Results: We present a method for long-term cryopreservation of CSF immune cells for downstream single cell RNA and T cell receptor sequencing (scRNA-TCRseq) analysis. We observe preservation of CSF immune cells, consisting primarily of memory CD4+ and CD8+ T cells. We then utilize unbiased bioinformatics approaches to quantify and visualize TCR sequence similarity within and between disease groups. By this method, we identify clusters of disease-associated, antigen-specific TCRs from clonally expanded CSF T cells of patients with neurodegenerative diseases. Conclusions: Here, we provide a standardized approach for long-term storage of CSF immune cells. Additionally, we present unbiased bioinformatic approaches that will facilitate the discovery of target antigens of clonally expanded T cells in neurodegenerative diseases. These novel methods will help improve our understanding of adaptive immunity in the central nervous system.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

DOI
10.1186/s13024-021-00423-w

Adenine base editing efficiently restores the function of Fanconi anemia hematopoietic stem and progenitor cells

NOMIS Researcher(s)

Published in

December 1, 2022

Fanconi Anemia (FA) is a debilitating genetic disorder with a wide range of severe symptoms including bone marrow failure and predisposition to cancer. CRISPR-Cas genome editing manipulates genotypes by harnessing DNA repair and has been proposed as a potential cure for FA. But FA is caused by deficiencies in DNA repair itself, preventing the use of editing strategies such as homology directed repair. Recently developed base editing (BE) systems do not rely on double stranded DNA breaks and might be used to target mutations in FA genes, but this remains to be tested. Here we develop a proof of concept therapeutic base editing strategy to address two of the most prevalent FANCA mutations in patient hematopoietic stem and progenitor cells. We find that optimizing adenine base editor construct, vector type, guide RNA format, and delivery conditions leads to very effective genetic modification in multiple FA patient backgrounds. Optimized base editing restored FANCA expression, molecular function of the FA pathway, and phenotypic resistance to crosslinking agents. ABE8e mediated editing in primary hematopoietic stem and progenitor cells from FA patients was both genotypically effective and restored FA pathway function, indicating the potential of base editing strategies for future clinical application in FA.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1038/s41467-022-34479-z

Social alignment matters: Following pandemic guidelines is associated with better wellbeing

NOMIS Researcher(s)

Published in

December 1, 2022

Background: In response to the Covid-19 pandemic, most countries implemented physical distancing measures. Many mental health experts warned that through increasing social isolation and anxiety, these measures could negatively affect psychosocial wellbeing. However, socially aligning with others by adhering to these measures may also be beneficial for wellbeing. Methods: We examined these two contrasting hypotheses using cross-national survey data (N = 6675) collected fortnightly from participants in 115 countries over 3 months at the beginning of the pandemic. Participants reported their wellbeing, perceptions of how vulnerable they were to Covid-19 (i.e., high risk of infection) and how much they, and others in their social circle and country, were adhering to the distancing measures. Results: Linear mixed-effects models showed that being a woman, having lower educational attainment, living alone and perceived high vulnerability to Covid-19 were risk factors for poorer wellbeing. Being young (18–25) was associated with lower wellbeing, but longitudinal analyses showed that young people’s wellbeing improved over 3 months. In contrast to widespread views that physical distancing measures negatively affect wellbeing, results showed that following the guidelines was positively associated with wellbeing even for people in high-risk groups. Conclusions: These findings provide an important counterpart to the idea that pandemic containment measures such as physical distancing negatively impacted wellbeing unequivocally. Despite the overall burden of the pandemic on psychosocial wellbeing, social alignment with others can still contribute to positive wellbeing. The pandemic has manifested our propensity to adapt to challenges, particularly highlighting how social alignment can forge resilience.

Research field(s)
Health Sciences, Public Health & Health Services, Public Health

DOI
10.1186/s12889-022-13130-y

Diffusion of punishment in collective norm violations

NOMIS Researcher(s)

Published in

December 1, 2022

People assign less punishment to individuals who inflict harm collectively, compared to those who do so alone. We show that this arises from judgments of diminished individual causal responsibility in the collective cases. In Experiment 1, participants (N = 1002) assigned less punishment to individuals involved in collective actions leading to intentional and accidental deaths, but not failed attempts, emphasizing that harmful outcomes, but not malicious intentions, were necessary and sufficient for the diffusion of punishment. Experiments 2.a compared the diffusion of punishment for harmful actions with ‘victimless’ purity violations (e.g., eating a dead human’s flesh as a group; N = 752). In victimless cases, where the question of causal responsibility for harm does not arise, diffusion of collective responsibility was greatly reduced—an outcome replicated in Experiment 2.b (N = 479). Together, the results are consistent with discounting in causal attribution as the underlying mechanism of reduction in proposed punishment for collective harmful actions.

Research field(s)
Health Sciences, Psychology & Cognitive Sciences, Experimental Psychology

DOI
10.1038/s41598-022-19156-x

Expression of the transcription factor PU.1 induces the generation of microglia-like cells in human cortical organoids

NOMIS Researcher(s)

Published in

December 1, 2022

Microglia play a role in the emergence and preservation of a healthy brain microenvironment. Dysfunction of microglia has been associated with neurodevelopmental and neurodegenerative disorders. Investigating the function of human microglia in health and disease has been challenging due to the limited models of the human brain available. Here, we develop a method to generate functional microglia in human cortical organoids (hCOs) from human embryonic stem cells (hESCs). We apply this system to study the role of microglia during inflammation induced by amyloid-β (Aβ). The overexpression of the myeloid-specific transcription factor PU.1 generates microglia-like cells in hCOs, producing mhCOs (microglia-containing hCOs), that we engraft in the mouse brain. Single-cell transcriptomics reveals that mhCOs acquire a microglia cell cluster with an intact complement and chemokine system. Functionally, microglia in mhCOs protect parenchyma from cellular and molecular damage caused by Aβ. Furthermore, in mhCOs, we observed reduced expression of Aβ-induced expression of genes associated with apoptosis, ferroptosis, and Alzheimer’s disease (AD) stage III. Finally, we assess the function of AD-associated genes highly expressed in microglia in response to Aβ using pooled CRISPRi coupled with single-cell RNA sequencing in mhCOs. In summary, we provide a protocol to generate mhCOs that can be used in fundamental and translational studies as a model to investigate the role of microglia in neurodevelopmental and neurodegenerative disorders.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

DOI
10.1038/s41467-022-28043-y

Sirtuin-1 sensitive lysine-136 acetylation drives phase separation and pathological aggregation of TDP-43

NOMIS Researcher(s)

Published in

December 1, 2022

Trans-activation response DNA-binding protein of 43 kDa (TDP-43) regulates RNA processing and forms neuropathological aggregates in patients with amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Investigating TDP-43 post-translational modifications, we discovered that K84 acetylation reduced nuclear import whereas K136 acetylation impaired RNA binding and splicing capabilities of TDP-43. Such failure of RNA interaction triggered TDP-43 phase separation mediated by the C-terminal low complexity domain, leading to the formation of insoluble aggregates with pathologically phosphorylated and ubiquitinated TDP-43. Introduction of acetyl-lysine at the identified sites via amber suppression confirmed the results from site-directed mutagenesis. K84-acetylated TDP-43 showed cytoplasmic mislocalization, and the aggregation propensity of K136-acetylated TDP-43 was confirmed. We generated antibodies selective for TDP-43 acetylated at these lysines, and found that sirtuin-1 can potently deacetylate K136-acetylated TDP-43 and reduce its aggregation propensity. Thus, distinct lysine acetylations modulate nuclear import, RNA binding and phase separation of TDP-43, suggesting regulatory mechanisms for TDP-43 pathogenesis.

Research field(s)
Health Sciences, Biomedical Research, Biochemistry & Molecular Biology

DOI
10.1038/s41467-022-28822-7

Comparative analysis of machine learning algorithms for multi-syndrome classification of neurodegenerative syndromes

NOMIS Researcher(s)

Published in

December 1, 2022

Importance: The entry of artificial intelligence into medicine is pending. Several methods have been used for the predictions of structured neuroimaging data, yet nobody compared them in this context. Objective: Multi-class prediction is key for building computational aid systems for differential diagnosis. We compared support vector machine, random forest, gradient boosting, and deep feed-forward neural networks for the classification of different neurodegenerative syndromes based on structural magnetic resonance imaging. Design, setting, and participants: Atlas-based volumetry was performed on multi-centric T1-weighted MRI data from 940 subjects, i.e., 124 healthy controls and 816 patients with ten different neurodegenerative diseases, leading to a multi-diagnostic multi-class classification task with eleven different classes. Interventions: N.A. Main outcomes and measures: Cohen’s kappa, accuracy, and F1-score to assess model performance. Results: Overall, the neural network produced both the best performance measures and the most robust results. The smaller classes however were better classified by either the ensemble learning methods or the support vector machine, while performance measures for small classes were comparatively low, as expected. Diseases with regionally specific and pronounced atrophy patterns were generally better classified than diseases with widespread and rather weak atrophy. Conclusions and relevance: Our study furthermore underlines the necessity of larger data sets but also calls for a careful consideration of different machine learning methods that can handle the type of data and the classification task best.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

DOI
10.1186/s13195-022-00983-z

Distinct cell type-specific protein signatures in GRN and MAPT genetic subtypes of frontotemporal dementia

NOMIS Researcher(s)

Published in

December 1, 2022

Frontotemporal dementia is characterized by progressive atrophy of frontal and/or temporal cortices at an early age of onset. The disorder shows considerable clinical, pathological, and genetic heterogeneity. Here we investigated the proteomic signatures of frontal and temporal cortex from brains with frontotemporal dementia due to GRN and MAPT mutations to identify the key cell types and molecular pathways in their pathophysiology. We compared patients with mutations in the GRN gene (n = 9) or with mutations in the MAPT gene (n = 13) with non-demented controls (n = 11). Using quantitative proteomic analysis on laser-dissected tissues we identified brain region-specific protein signatures for both genetic subtypes. Using published single cell RNA expression data resources we deduced the involvement of major brain cell types in driving these different protein signatures. Subsequent gene ontology analysis identified distinct genetic subtype- and cell type-specific biological processes. For the GRN subtype, we observed a distinct role for immune processes related to endothelial cells and for mitochondrial dysregulation in neurons. For the MAPT subtype, we observed distinct involvement of dysregulated RNA processing, oligodendrocyte dysfunction, and axonal impairments. Comparison with an in-house protein signature of Alzheimer’s disease brains indicated that the observed alterations in RNA processing and oligodendrocyte function are distinct for the frontotemporal dementia MAPT subtype. Taken together, our results indicate the involvement of different brain cell types and biological mechanisms in genetic subtypes of frontotemporal dementia. Furthermore, we demonstrate that comparison of proteomic profiles of different disease entities can separate general neurodegenerative processes from disease-specific pathways, which may aid the development of disease subtype-specific treatment strategies.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

DOI
10.1186/s40478-022-01387-8

Improved gRNA secondary structures allow editing of target sites resistant to CRISPR-Cas9 cleavage

NOMIS Researcher(s)

Published in

December 1, 2022

The first step in CRISPR-Cas9-mediated genome editing is the cleavage of target DNA sequences that are complementary to so-called spacer sequences in CRISPR guide RNAs (gRNAs). However, some DNA sequences are refractory to CRISPR-Cas9 cleavage, which is at least in part due to gRNA misfolding. To overcome this problem, we have engineered gRNAs with highly stable hairpins in their constant parts and further enhanced their stability by chemical modifications. The ‘Genome-editing Optimized Locked Design’ (GOLD)-gRNA increases genome editing efficiency up to around 1000-fold (from 0.08 to 80.5%) with a mean increase across different other targets of 7.4-fold. We anticipate that this improved gRNA will allow efficient editing regardless of spacer sequence composition and will be especially useful if a desired genomic site is difficult to edit.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1038/s41467-022-28137-7

SepN is a septal junction component required for gated cell–cell communication in the filamentous cyanobacterium Nostoc

NOMIS Researcher(s)

Published in

December 1, 2022

Multicellular organisms require controlled intercellular communication for their survival. Strains of the filamentous cyanobacterium Nostoc regulate cell–cell communication between sister cells via a conformational change in septal junctions. These multi-protein cell junctions consist of a septum spanning tube with a membrane-embedded plug at both ends, and a cap covering the plug on the cytoplasmic side. The identities of septal junction components are unknown, with exception of the protein FraD. Here, we identify and characterize a FraD-interacting protein, SepN, as the second component of septal junctions in Nostoc. We use cryo-electron tomography of cryo-focused ion beam-thinned cyanobacterial filaments to show that septal junctions in a sepN mutant lack a plug module and display an aberrant cap. The sepN mutant exhibits highly reduced cell–cell communication rates, as shown by fluorescence recovery after photobleaching experiments. Furthermore, the mutant is unable to gate molecule exchange through septal junctions and displays reduced filament survival after stress. Our data demonstrate the importance of controlling molecular diffusion between cells to ensure the survival of a multicellular organism.

Research field(s)
Health Sciences, Biomedical Research, Microbiology

DOI
10.1038/s41467-022-34946-7

Brain aging is faithfully modelled in organotypic brain slices and accelerated by prions

NOMIS Researcher(s)

Published in

December 1, 2022

Mammalian models are essential for brain aging research. However, the long lifespan and poor amenability to genetic and pharmacological perturbations have hindered the use of mammals for dissecting aging-regulatory molecular networks and discovering new anti-aging interventions. To circumvent these limitations, we developed an ex vivo model system that faithfully mimics the aging process of the mammalian brain using cultured mouse brain slices. Genome-wide gene expression analyses showed that cultured brain slices spontaneously upregulated senescence-associated genes over time and reproduced many of the transcriptional characteristics of aged brains. Treatment with rapamycin, a classical anti-aging compound, largely abolished the time-dependent transcriptional changes in naturally aged brain slice cultures. Using this model system, we discovered that prions drastically accelerated the development of age-related molecular signatures and the pace of brain aging. We confirmed this finding in mouse models and human victims of Creutzfeldt-Jakob disease. These data establish an innovative, eminently tractable mammalian model of brain aging, and uncover a surprising acceleration of brain aging in prion diseases.

Research field(s)
Health Sciences, Biomedical Research, Developmental Biology

DOI
10.1038/s42003-022-03496-5

Deep residual inception encoder-decoder network for amyloid PET harmonization

NOMIS Researcher(s)

Published in

December 1, 2022

Introduction: Multiple positron emission tomography (PET) tracers are available for amyloid imaging, posing a significant challenge to consensus interpretation and quantitative analysis. We accordingly developed and validated a deep learning model as a harmonization strategy. Method: A Residual Inception Encoder-Decoder Neural Network was developed to harmonize images between amyloid PET image pairs made with Pittsburgh Compound-B and florbetapir tracers. The model was trained using a dataset with 92 subjects with 10-fold cross validation and its generalizability was further examined using an independent external dataset of 46 subjects. Results: Significantly stronger between-tracer correlations (P <.001) were observed after harmonization for both global amyloid burden indices and voxel-wise measurements in the training cohort and the external testing cohort. Discussion: We proposed and validated a novel encoder-decoder based deep model to harmonize amyloid PET imaging data from different tracers. Further investigation is ongoing to improve the model and apply to additional tracers.

Research field(s)
Health Sciences, Clinical Medicine, Neurology & Neurosurgery

DOI
10.1002/alz.12564

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