Formation of Actin Mesh Structures and Alpha-Smooth Muscle Actin Dynamics in Fibroblasts Contribute to Dermal Regeneration in Mouse Fetus

This study investigates the role of actin dynamics and alpha-smooth muscle actin (α-SMA) in dermal regeneration and scar formation in mouse fetuses. It was observed that actomyosin bundles form a mesh-like pattern in the dermis at embryonic day 13 (E13), promoting regeneration, while at E15 and later, these structures contribute to scar formation. In E13 dermal fibroblasts, α-SMA is found in the cytoplasm independently of actin, whereas in E15 and later stages, α-SMA and actin coincide due to TGFβ-1 stimulation, with α-SMA notably expressed in the nucleus by E17, correlating with scarring. The study suggests that the distinct localization of actin and α-SMA is crucial for dermal regeneration, offering insights for potential wound regeneration therapies.