Native cell niche-inspired multiorder nanoassemblies orchestrate integrated interaction networks to guide muscle...

Volumetric muscle loss (VML) is a severe injury that overwhelms the intrinsic repair capacity of muscles and eventually causes chronic fibrosis and disability. However, efficient clinical therapeutics for VML remain unavailable. Here, we revealed that cell niche damage caused by VML disrupts pro-regenerative signaling networks (e.g., matrix-cell and cell-cell interactions) and leads to muscle fibrosis. Inspired by the architecture of the native muscle cell niche, we designed multiorder nanoassemblies (Multi-Nano) to coordinately reconstruct integrated interaction networks in the VML niche at multiple levels. Multi-Nano comprises three bioactive building blocks, in which differentiating myoblast-derived nanovesicles (NVs) can elicit the myogenic processes of muscle cells; synthetic VEGF mRNA can be highly efficiently delivered by myogenic NVs to enhance myocyte-endothelial cell interactions and ordered microvascular formation by inducing myocyte VEGF secretion, and muscle-specific matrix (LN)-functionalized peptide nanofiber scaffolds can support cell-matrix and cell-cell interactions, thereby jointly creating an artificial niche for promoting functional muscle regeneration without scar formation after VML. Multi-Nano shows superior therapeutic potency compared to its individual component and demonstrates favorable biosafety in vivo. This study highlights that the tailored design of a tissue-specific nanoenvironment offers a promising avenue to modulate complex signaling networks for the repair of hard-to-heal tissues.