Spiny mouse can regenerate hair follicles, cartilage, and skin in ear punches provides a new opportunity to uncover molecular changes that permit regeneration in an adult mammal. Using their ears as a regenerative system, the Seifert lab has studied how these animals generate and maintain a regeneration blastema. A longstanding question in regeneration biology has centered on whether the mammalian immune system and scarring contributes to constrain regenerative capacity. We are currently developing a project to examine the local response to injury and test the hypothesis that trade-offs in immunity along (1) innate vs. adaptive and (2) pro vs. anti-inflammatory axes underlie variation in the ability and rate of regeneration. Ongoing work by Dr. Seifert and his group have demonstrated that resident macrophages are required for tissue regeneration and that infiltrating macrophages regulate inflammatory magnitude. Additionally, his group has uncovered cellular mechanisms that direct injury signals to regulate the balance between proliferation and cellular senescence, mechanisms that can be affected to drive regenerative healing in laboratory mice.