ECM-Focused Proteomic Analysis of Ear Punch Regeneration in <i>Acomys cahirinus</i>

While significant acute injury leads to a functionally deficient fibrotic scar in mammals, the spiny mouse <i>Acomys cahirinus</i> has evolved scar-free regeneration of severely damaged tissue. Extracellular matrix (ECM) composition is a critical regulator of wound repair, and previous studies have suggested that alterations in its expression may be responsible for the differences in regenerative capacity observed between <i>Mus musculus</i> and <i>A. cahirinus</i>, yet analysis of this critical tissue component has been limited in previous studies by its insolubility. Here, we utilize a two-step ECM-optimized extraction to perform proteomic analysis of tissue composition during wound repair after full-thickness ear punches in <i>A. cahirinus</i> and <i>M. musculus</i> from weeks 1 to 4 postinjury. We observe changes in various ECM proteins implicated in wound regeneration and fibrosis, including collagens, provisional matrix, coagulation proteins, and matricryptic signaling domains. We additionally report differences in cross-linking enzyme activity and ECM protein solubility between species. Furthermore, we observed rapid and sustained increases in pro-regenerative macrophage markers in <i>Acomys</i> but not in <i>Mus.</i> Together, these findings indicate that ECM differences contribute to the pro-regenerative restoration of functional tissue seen in <i>Acomys</i> and implicate potential targets for future therapies to attenuate scar formation in other mammals.