Astrocytic glycogen aggregates induce ATAD3A oligomerization mediated mitochondrial fragmentation and impede stroke recovery

Ischemic stroke induces pathological glycogen deposition in astrocytes, but its role in post-injury neural dysfunction remains undefined. We reveal that glycogen-laden astrocytes in the ischemic penumbra undergo ATAD3A-dependent mitochondrial fragmentation via a stress granule-mediated mechanism, exacerbating neuronal injury and hindering functional recovery. Mechanistic studies demonstrate that glycogen aggregates sequester cytoplasmic HDAC3, enabling its translocation to mitochondria. There, HDAC3 deacetylates outer mitochondrial membrane protein ATAD3A, promoting oligomerization-driven mitochondrial fission. Astrocyte-specific ATAD3A ablation prevents stroke-induced synaptic disorganization, neural circuit disruption, and cognitive deficits. Therapeutically, pharmacologic or genetic exhaustion of astrocytic glycogen and HDAC3 inhibition reverse glycogen accumulation, rescue mitochondrial architecture/function, and restore synaptic plasticity and circuit reorganization, thereby acting synergistically to enhance post-stroke recovery. Our work identifies glycogen stress granules as pathogenic signaling hubs linking astrocytic metabolic stress to mitochondrial failure through compartmentalized HDAC3-ATAD3A crosstalk, and proposes a dual-target paradigm addressing both substrate overload and protein acetylation dynamics for stroke neurorestoration.