miRNATissueAtlas 2025: an update to the uniformly processed and annotated human and mouse non-coding RNA tissue atlas

MiRNAs represent a non-coding RNA class that regulate gene expression and pathways. While miRNAs are evolutionary conserved most data stems from Homo sapiens and Mus musculus. As miRNA expression is highly tissue specific, we developed miRNATissueAtlas to comprehensively explore this landscape in H. sapiens. We expanded the H. sapiens tissue repertoire and included M. musculus. In past years, the number of public miRNA expression datasets has grown substantially. Our previous releases of the miRNATissueAtlas represent a great framework for a uniformly pre-processed and label-harmonized resource containing information on these datasets. We incorporate the respective data in the newest release, miRNATissueAtlas 2025, which contains expressions from 9 classes of ncRNA from 799 billion reads across 61 593 samples for H. sapiens and M. musculus. The number of organs and tissues has increased from 28 and 54 to 74 and 373, respectively. This number includes physiological tissues, cell lines and extracellular vesicles. New tissue specificity index calculations build atop the knowledge of previous iterations. Calculations from cell lines enable comparison with physiological tissues, providing a valuable resource for translational research. Finally, between H. sapiens and M. musculus, 35 organs overlap, allowing cross-species comparisons. The updated miRNATissueAtlas 2025 is available at https://www.ccb.uni-saarland.de/tissueatlas2025.