International Journal of Developmental Neuroscience · Nov 3, 2026
ν‐Neoblasts and Their Molecular Signatures in Planarian Brain Regeneration
By Pramanik S
Brain regeneration is a remarkable feature of planarians. Pluripotent neoblasts (Nb) drive whole‐body regeneration, whereas ν (nu) neoblasts represent a specialized subpopulation that acts as neural progenitors and contributes to neurogenesis. The molecular mechanisms underlying Nb differentiation into ν‐Nb and the subsequent self‐renewal, proliferation and differentiation of ν‐Nb into distinct neuronal subtypes remain poorly understood. Single‐cell RNA‐seq analysis revealed that the Nb2 cluster, characterized by tspan‐1 expression, could be a pluripotent stem cell population, whereas the tgs‐1 ⁺ subpopulation within this cluster has been proposed to represent neural‐specialized Nb. Intriguingly, the Nb11 cluster, characterized by the expression of transcription factors such as TGS‐1, PROX‐1, POU4L‐1 and PAX6A, has also been proposed as a potential neural stem cell population involved in planarian brain regeneration. The overlapping transcriptional signatures of the Nb2 and Nb11 populations imply a new challenge in definitively distinguishing pluripotent Nb cells from neural Nb cells, highlighting the need for functional lineage‐tracing studies to identify distinct neural stem cell populations and establish molecular markers specific to their neural fates. This article provides a comprehensive current understanding of the molecular mechanisms governing Nb differentiation into ν‐Nb, their subsequent neuronal lineage specification, and their integration into functional brain tissue during regeneration in planarians.