Biology subjects

Daskalakis, N.

Publications and source records attributed to Daskalakis, N..

5 recordsLinked to original sources

bioRxiv2026

A microRNA atlas of the human prefrontal cortex across the adult lifespan

Aging of the human brain is characterized by widespread changes in gene expression regulated in part by microRNAs (miRNAs). We present a lifespan miRNA atlas of the human dorsolateral prefrontal cortex generated from small RNA sequencing of 113 postmortem samples spanning 18 to 100 years of age. Differential expression analysis revealed progressive age-associated remodeling of miRNA expression, with the strongest differences observed between old and young individuals. Among the significantly altered miRNAs, miR-34a-5p emerged as one of the most robustly upregulated miRNAs in the aged cortex, alongside additional aging-associated miRNAs including miR-155-5p, miR-132-3p, miR-212-3p, miR-449a, and members of the miR-302 family. This atlas provides a resource for investigating miRNA dysregulation and small RNA regulatory networks during human cortical aging.

neuroscience↗

bioRxiv2026

Revealing the convergence of disease- and risk-associated circular RNAs in schizophrenia and bipolar disorder

Circular RNAs (circRNAs) remain an underexplored layer of transcriptomic regulation in psychiatric disorders. We quantified circRNA expression from 1,022 [518 neurotypical, 365 schizophrenia (SCZ) and 139 bipolar disorder (BIP)] postmortem cortex samples from PsychENCODE consortium cohorts and integrated these profiles with matched linear RNA and genotype profiles. We identified 23 SCZ-associated and 3 BIP-associated differentially expressed circRNAs (FDR<0.05; FDR-circDEG). We trained genetically regulated circRNA expression (circGReX) models using neurotypicals and applied them to SCZ and BIP GWAS to perform Transcriptomic Wide association analysis (TWAS) which identified 22 and 4 circGReX trait associations (circGTAs), respectively. Pathway enrichment of circDEGs and circGTAs implicated neuronal and synaptic processes for both disorders. In UK Biobank, circGReX-imaging associations were predominantly negatively correlated with SCZ and BIP circGTAs, but positively correlated with Alzheimers disease circGTAs. circKLHL24 isoforms showed the most prominent imaging associations. Many co-expression modules containing our FDR-circDEGs were enriched for psychiatric and neurodegenerative risk genes, including our identified circGTAs, and these modules were enriched for cognitive and neurodevelopmental traits. To conclude, circRNAs represent a distinct regulatory layer in psychiatric disorders, linking genetic risk to synaptic biology, brain structure and cognition through disease-specific expression, TWAS prioritization, and imaging associations.

neuroscience↗

bioRxiv2026

Aging-related Transcriptomic Changes with Spatial Resolution in the Human Prefrontal Cortex

The human prefrontal cortex (PFC), whose laminar organization is essential for cognitive function, is among the first regions to show age-related functional decline1,2. Single-cell sequencing studies revealed cell type-dependent aging effects but lacked spatial specificity3-6. Spatial transcriptomics (ST) advanced our molecular understanding of the human PFC7, yet whether aging-driven changes differ across PFC layers remains unclear. Here, we performed whole-transcriptome ST on postmortem PFC from 37 individuals across the adult lifespan. We mapped cortical layers and revealed aging mechanisms across layers. This represents one of the largest and most comprehensive lifespan ST analysis of the human PFC brain, offering crucial insight into how the brain ages and identifying potential molecular targets to mitigate cognitive aging and extend healthspan.

neuroscience↗

bioRxiv2019

PTSD Biomarker Database: Deep Dive Meta-database for PTSD Biomarkers, Visualizations, and Analysis Tools

The PTSD Biomarker Database (PTSDDB) is a database that provides a landscape view of physiological markers being studied as putative biomarkers in the current post-traumatic stress disorder (PTSD) literature to enable researchers to quickly explore and compare findings. The PTSDDB currently contains over 900 biomarkers and their relevant information from 109 original articles published from 1997 to 2017. Further, the curated content stored in this database is complemented by a web application consisting of multiple interactive visualizations that enable the investigation of biomarker knowledge in PTSD (e.g., clinical study metadata, biomarker findings, experimental methods, etc.) by compiling results from biomarker studies to visualize the level of evidence for single biomarkers and across functional categories. This resource is the first attempt, to the best of our knowledge, to capture and organize biomarker and metadata in the area of PTSD for storage in a comprehensive database that may, in turn, facilitate future analysis and research in the field. Database URLhttps://ptsd.scai.fraunhofer.de

bioinformatics↗

bioRxiv2018

Endo-lysosomal sorting and degradation of Tau mediates glucocorticoid-driven hippocampalmalfunction

Emerging studies implicate Tau as an essential mediator of neuronal atrophy and cognitive impairment in Alzheimers disease (AD), yet the factors that precipitate Tau dysfunction in AD are poorly understood. Chronic environmental stress and elevated glucocorticoids (GC), the major stress hormones, are associated with increased risk of AD, and have been shown to trigger intracellular Tau accumulation and downstream Tau-dependent neuronal dysfunction. However, the mechanisms through which stress and GC disrupt Tau clearance and degradation in neurons remain unclear. Here, we demonstrate that Tau undergoes degradation via endolysosomal sorting in a pathway requiring the small GTPase Rab35 and the endosomal sorting complex required for transport (ESCRT) machinery. Furthermore, we find that GC impair Tau degradation by decreasing Rab35 levels, and that AAV-mediated expression of Rab35 in the hippocampus rescues GC-induced Tau accumulation and related neurostructural deficits. These studies indicate that the Rab35/ESCRT pathway is essential for Tau clearance and part of the mechanism through which GC precipitate brain pathology.

neuroscience↗