Biology subjects

Scheibye-Knudsen, M.

Publications and source records attributed to Scheibye-Knudsen, M..

11 recordsLinked to original sources

bioRxiv2026

BrainYears: A functional EEG-based brain age clock enables intervention-ready measurements of brain aging

Biological brain aging is a major determinant of cognitive decline and neurodegenerative disease, yet scalable and intervention-ready brain aging biomarkers remain limited. Here, we develop an electroencephalography (EEG)-based brain age clock using machine learning trained on high-dimensional neural features across the adult lifespan. Using 643 features captured from a Sens.ai headset and controller device, the model predicts chronological age with high accuracy (Pearson r = 0.92; MAE = 4.43 years) and yields an interpretable set of age-informative neural features capturing functional signatures of brain aging. Unlike MRI-based approaches, this EEG-based clock is non-invasive, transportable, cost- effective and suitable for repeated at-home longitudinal measurement. Furthermore, in a longitudinal neuromodulation program, BrainYears-predicted brain age decreased by a mean of -5.18 years in the intervention group whereas a minimal-exposure comparison group showed no change on average (+0.07 years). Together, this work introduces a functional brain aging biomarker and an intervention-ready platform for quantifying brain age modulation.

bioinformatics↗

bioRxiv2025

DORA AI Scientist: Multi-agent Virtual Research Team for Scientific Exploration Discovery and Automated Report Generation

Modern goal-oriented scientific research process involves hierarchical teams of researchers of diverse backgrounds performing generalist and domain-specific tasks. Many of these tasks include hypothesis generation, literature review, data collection, cleanup, processing and analysis, experimental design, virtual and physical experiments, research report and academic paper writing, reference management, bibliography and quality control. Most of these tasks can be performed automatically or in a co-pilot mode by the generative reinforcement learning systems. In this paper, we introduce a versatile multi-agent scientific exploration and draft outline research assistant (DORA), which provides multiple templates and workflows for automated or semi-automated research studies and report generation. Under user guidance, it employs hierarchical teams of AI agents based on the plug-and-play generalist and domain-specific large language models (LLMs) exploiting a variety of specialized research tools and open data repositories and generates high-quality research outputs publication drafts with maximally-accurate references. DORA is designed to minimize the time and effort required for manuscript preparation, thereby enabling researchers to devote more attention to high-value discovery tasks. The system is constantly evolving with user feedback with regular feature and resource updates. The platform is available at https://dora.insilico.com.

bioinformatics↗

bioRxiv2024

Utilizing blood single-cell transcriptomics to integrate intrinsic and systemic immune aging

Biomarkers of aging provide insight into the biological effects of interventions and diseases. However, most biomarkers today are based on measurements derived from bulk cell measurements, making it challenging to interpret whether an effect is due to changes in cell type composition (systemic factors) or a cell intrinsic effect. Single-cell RNA sequencing provides a unique platform to simultaneously compare aging-associated changes on both a cellular and bulk level. We first generated a single-cell combined automated human blood cell type and age predictor (clock) for six distinct human T cell subsets. We applied these tools to find acute COVID is associated with a shift in CD8+ cytotoxic cell proportions, while cell type proportions are stable in patients with HIV on long-term ART treatment (HIV+ART). Both COVID and HIV+ART were associated with an increase in naive CD8 T cell transcriptomic age. We further found our single-cell aging biomarker is linked to ribosomal gene expression and has a link to mean cellular transcript length. This study highlights the potential of single cell transcriptomic biomarkers for understanding how the human immune system is impacted by age-associated systemic changes in cell type composition and intrinsic cellular aging.

immunology↗

bioRxiv2024

The mitochondrial unfolded protein response promotes senescence in human microglia by increasing S-adenosylmethionine availability for polyamine synthesis.

Mitochondria have evolved a specialized mitochondrial unfolded protein response (UPRmt) to maintain proteostasis and promote recovery under stress. Studies in simple organisms have shown that UPRmt activation in glial cells supports proteostasis through beneficial noncell-autonomous communication with neurons. However, the role of mitochondrial stress responses in the human brain remains unclear. To address this gap, we investigated the cell type-specific effects of mitochondrial proteotoxic stress using human induced pluripotent stem cell-derived neuronal and glial cultures, as well as brain organoids. We show that mitochondrial proteotoxic stress induces metabolic rewiring in human microglia, marked by depletion of S-adenosylmethionine and lipid remodeling, ultimately leading to a senescent phenotype. Using human neuronal-glial tricultures and microglia-containing brain organoids, we identified the specific contributions of microglia to brain senescence and mitochondrial stress-driven neurodegenerative processes. UPRmt activation disrupts microglial communication with neighboring cells, triggering inflammatory signaling and impairing proteostasis. Together, these findings reveal how impaired mitochondrial proteostasis alters intercellular networks and identify a critical role for the UPRmt in neurodegenerative disease pathogenesis.

neuroscience↗

bioRxiv2023

Chronically disrupted sleep induces senescence in the visceral adipose tissue of C57BL/6J mice

The role of sleep in systemic aging remains poorly understood, despite sleeps essential function in preserving overall health and the prevalence of reduced sleep quality in modern society. Although reduced sleep correlates with an elevated risk of age-related diseases in humans, the mechanisms underlying this are unclear. In this study, we established a link between sleep and aging by demonstrating that disrupting sleep in C57BL/6 mice drives cellular senescence in the visceral adipose tissue. Sleep disruption also led to increased oxidative stress and DNA damage, both recognized triggers for senescence induction. Cellular senescence is implicated in numerous age-related conditions which are associated with insufficient sleep, such as cardiovascular disease, type 2 diabetes, and chronic inflammation. Our findings identify an accumulation of senescent cells in the adipose tissue, which serves as a potential target through which disturbed sleep accelerates the aging process and elevates the risk of age-related diseases.

molecular biology↗

bioRxiv2023

The human pathome shows sex specific aging patterns post-development

Little is known about tissue specific changes that occur with aging in humans. Using the description of 33 million histological samples we extract thousands of age- and mortality-associated features from text narratives that we call The Human Pathome (pathoage.com). Notably, we can broadly determine when pathological aging starts, indicating a sexual dimorphism with females aging earlier but slower and males aging later but faster. Using machine learning, we employ unsupervised topic-modelling to identify terms and themes that predict age and mortality. As a proof of principle, we cross reference these terms in PubMed to identify nintedanib as a potential aging intervention and show that nintedanib reduces markers of cellular senescence, reduces pro-fibrotic gene pathways in senescent cells and extends the lifespan of fruit flies. Our findings pave the way for expanded exploitation of population datasets towards discovery of novel aging interventions.

physiology↗

bioRxiv2022

Histone malonylation is regulated by SIRT5 and KAT2A

The posttranslational modification lysine malonylation is found in many proteins, including histones. However, it remains unclear whether histone malonylation is regulated or functionally relevant. Here, we report that availability of malonyl-co-enzyme A (malonyl-CoA), an endogenous provider of malonyl groups, affects lysine malonylation, and that the deacylase SIRT5 selectively reduces malonylation of histones. To determine if histone malonylation is enzymatically catalyzed, we knocked down each of the 22 lysine acetyltransferases (KATs) to test their malonyltransferase potential. KAT2A knockdown in particular reduced histone malonylation levels. By mass spectrometry, H2B_K5 was highly malonylated and significantly regulated by SIRT5 in mouse brain and liver. Acetyl-CoA carboxylase (ACC), the malonyl-CoA producing enzyme, was partly localized in the nucleolus, and histone malonylation increased nucleolar area and ribosomal RNA expression. Levels of global lysine malonylation and ACC expression were higher in older mouse brains than younger mice. These experiments highlight the role of histone malonylation in ribosomal gene expression.

molecular biology↗

bioRxiv2022

Human Elp3/Kat9 is a mitochondrial tRNA modifying enzyme

Post-translational modifications, such as lysine acetylation, regulate the activity of diverse proteins across many cellular compartments. Protein deacetylation in mitochondria is catalyzed by the enzymatic activity of the NAD+-dependent deacetylase sirtuin 3 (SIRT3), however it remains unclear whether corresponding mitochondrial acetyltransferases exist. We used a bioinformatics approach to search for mitochondrial proteins with an acetyltransferase catalytic domain, and identified a novel splice variant of ELP3 (mt-ELP3) of the elongator complex, which localizes to the mitochondrial matrix in mammalian cells. Unexpectedly, mt-ELP3 does not mediate mitochondrial protein acetylation but instead induces a post-transcriptional modification of mitochondrial-transfer RNAs (mt-tRNAs). Overexpression of mt-ELP3 leads to the protection of mt-tRNAs against the tRNA-specific RNase angiogenin, increases mitochondrial translation, and furthermore increases expression of OXPHOS complexes. This study thus identifies mt-ELP3 as a non-canonical mt-tRNA modifying enzyme.

molecular biology↗

bioRxiv2022

Ketones facilitate transcriptional resolution of secondary DNA structures in premature aging

There is currently no established intervention for Cockayne syndrome, a disease characterized by progressive early onset neurodegeneration with features of premature aging. Here, we tested if acetyl-CoA precursors, citrate and beta-hydroxybutyrate, could reduce features of Cockayne syndrome in three model systems. We identified the gene Helicase 89B as a homologue of CSB in drosophila and found that the ketone beta-hydroxybutyrate rescued features of premature aging in Hel89B deficient flies. In mammals, loss of the citrate carrier Indy exacerbated the phenotype of Csbm/m mice which was rescued by a ketogenic diet. The rescue effect appeared to be mediated through ketone stimulated histone acetylation and facilitation of transcriptional readthrough of secondary DNA structures. These findings link a ketogenic diet with transcriptional resolution of secondary structures and DNA repair.

physiology↗

bioRxiv2021

Deep Learning Shows Cellular Senescence Is a Barrier to Cancer Development

Cellular senescence is a critical component of aging and many age-related diseases, but understanding its role in human health is challenging in part due to the lack of exclusive or universal markers. Using neural networks, we achieve high accuracy in predicting senescence state and type from the nuclear morphology of DAPI-stained human fibroblasts, murine astrocytes and fibroblasts derived from premature aging diseases in vitro. After generalizing this approach, the predictor recognizes an increasing rate of senescent cells with age in H&E-stained murine liver tissue and human dermal biopsies. Evaluating corresponding medical records reveals that individuals with increased senescent cells have a significantly decreased rate of malignant neoplasms, lending support for the protective role of senescence in limiting cancer development. In sum, we introduce a novel predictor of cellular senescence and apply it to diagnostic medical images, indicating cancer occurs more frequently for those with a lower rate of senescence.

cell biology↗

bioRxiv2020

Inhibition of the neuromuscular acetylcholine receptor with atracurium activates FOXO/DAF-16-induced longevity

Transcriptome-based drug screening is emerging as a powerful tool to identify geroprotective compounds to intervene in age-related disease. We hypothesized that, by mimicking the transcriptional signature of the highly conserved longevity intervention of FOXO3 (daf-16 in worms) overexpression, we could identify and repurpose compounds with similar downstream effects to increase longevity. Our in silico screen, utilizing the LINCS transcriptome database of genetic and compound interventions, identified several FDA-approved compounds that activate FOXO downstream targets in mammalian cells. These included the neuromuscular blocker atracurium, which also robustly extends both lifespan and healthspan in C. elegans. This longevity is dependent on both daf-16 signaling and inhibition of the neuromuscular acetylcholine receptor. Other neuromuscular blockers tubocurarine and pancuronium caused similar healthspan benefits. We demonstrate nuclear localization of DAF-16 upon atracurium treatment, and, using RNAseq transcriptomics, identify activation of DAF-16 downstream effectors. Together, these data demonstrate the capacity to mimic genetic lifespan interventions with drugs, and in doing so, reveal that the neuromuscular acetylcholine receptor regulates the highly conserved FOXO/DAF-16 longevity pathway.

molecular biology↗