Asperous coordinates regenerative timing by regulating damage-induced WNT Signaling

Tissue regeneration requires precise control of signaling pathways to direct proliferation, differentiation, and patterning. While early responses to injury are well characterized, how differentiation is coordinated during later stages remains unclear. Here, we identify Asperous (Aspr), an EGF-repeat protein, as a regeneration-specific regulator inDrosophilawing discs. Aspr is dispensable for wing development but is strongly induced within 24 hours post-injury. Maintainingasprexpression inhibits differentiation and alters reparative growth, while loss impairs regeneration. Structural and expression analyses show Aspr is a membrane-associated extracellular protein secreted in extracellular vesicles (EVs), where it co-localizes with the WNT ligand Wingless (Wg). We find Aspr regulates post-injury but not developmental Wg signaling, potentially by influencing its secretion or availability via EVs. These findings suggest Aspr regulates WNT activity to ensure proper timing of cell fate specification during regeneration, revealing a mechanism by which signaling dynamics are temporally controlled during tissue repair.