Yingji Mao

1 Introduction Stem cell niches (SCNs) are specialized microenvironments that integrate multidimensional signals to preserve stemness, direct differentiation, and coordinate repair, thereby determining the regenerability of tissues.[1-3] This capacity varies hierarchically across tissues and anatomy owing to the spatial heterogeneity of SCNs. From a tissue perspective, the skin and liver harbor numerous, broadly distributed, and highly injury-responsive SCNs that enable rapid restoration of...