Intermuscular adipose tissue (IMAT) expansion is closely associated with cardiometabolic disease (CMD), yet its cellular organization and regulatory mechanisms remain poorly defined. Using bulk transcriptomics on human IMAT, we identified a distinct gene signature and functional regulators including adipogenic transcription factor early B-cell factor 2 (EBF2). By mapping this human signature to the spatial transcriptome of IMAT from mice with CMD, we unraveled discrete stromal niches surrounding muscle fibers, characterized by IMAT expansion and the coordinated activation of adipogenic, extracellular matrix, inflammatory, and metabolic pathways. Spatial analyses showed that fibro-adipogenic progenitor (FAP) abundance does not predict adipocyte formation, supporting a model of localized and context-dependent lineage transitions. Cross-species comparison revealed partial conservation of human IMAT gene programs, validating the mouse model and highlighting species-specific features. Functional experiments in human primary myoblasts showed that EBF2 is sufficient to induce adipogenic reprogramming. Our findings establish IMAT as an active, spatially organized remodeling niche and identify lineage plasticity as a central mechanism driving its expansion in metabolic disease.

SS is an employee of Boehringer Ingelheim and has stakeholder interests in Cellarity. The present work was carried out as an employee of the Helmholtz Zentrum Muenchen. HMGU. The other actors have no competing interests.

This study was funded by by the Helmholtz Association; the German Research Council (DFG) grants HO 2286/3-1 (iMAGO, subproject P4) to SMH and the DFG grant 455422993 (iMAGO, subproject TP3, GZ: PL825/3-1) to MAP, both part of the Research Unit FOR 5298; the DFG grant 536691227 within the Research Unit FOR 5795-1 (HyperMet) to KAD and to DL; the DFG grant 545363987 (CoMeT) to DL; the European Research Council ERC-CoG Yoyo-LepReSens no. 101002247, to PTP.; the ADA grant 1-14-CE-05, the National Institutes of Health grant R01DK089170, the NIH General Clinical Research grant RR-00036 and the Colorado Nutrition Obesity Research Center grant P30DK048520 to BCB.

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Ethics committee/IRB of the Colorado Multiple Institutional Review Board at the University of Colorado gave ethical approval for this work.

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