Spatiotemporal macrophage subtype specification guides the formation of dynamic multilayered regenerative inflammation zones during tissue repair


Pre-Clinical Research

Poster Number: S13


Andreas Patsalos, PhD, Johns Hopkins University School of Medicine, Laszlo Halasz, PhD, Johns Hopkins University School of Medicine, Darby Oleksak, Johns Hopkins University School of Medicine, Xiaoyan Wei, PhD, Johns Hopkins University School of Medicine, Thomas Conrad, PhD, Max Delbrück Center for Molecular Medicine, David Hammers, PhD, Myology Institute, University of Florida, H. Lee Sweeney, PhD, University of Florida, Laszlo Nagy, MD, PhD, Johns Hopkins University School of Medicine

Tissue regeneration is orchestrated by infiltrating myeloid-derived cells, particularly macrophages, that clear damaged cells and promote regenerative inflammation. How macrophages spatially adapt and diversify their functions to support the unique structural requirements of actively regenerating tissue remains unknown. Here, we reconstructed the dynamic trajectories of myeloid cells isolated from acutely-injured and early-stage dystrophic muscles. We identified divergent subsets of monocytes/macrophages and dendritic cells (DCs) and validated markers (e.g., GPNMB) associated with defined functional states. In dystrophic muscle, specialized repair-associated subsets exhibit distinct macrophage diversity and reduced DC heterogeneity. Coupling integrated spatial transcriptomics analyses with immunofluorescence uncovered striking subpopulation distribution and multilayered regenerative inflammation zones (RIZs) where distinct macrophage subsets organize functional tissue zones around damaged myofibers supporting all phases of regeneration. Importantly, intermittent small-molecule anti-inflammatory treatment disrupts the RIZs. Our findings suggest that macrophage subtypes mediate the highly ordered architecture of regenerative tissues, unveiling the principles of the structured yet dynamic nature of regenerative inflammation supporting effective tissue repair.