A lineage CLOUD for neoblasts. (March 2019)

• Record Type: Journal Article
• Authors: Tran, Thao Anh; Gentile, Luca
• Is Part Of: Seminars in cell & developmental biology. Volume 87(2019)
• Page Start: 22
• Page End: 29
• Publication Date: 2019-03
• Subjects: RNAi RNA interference -- WISH whole-mount in situ hybridization -- qPCR quantitative polymerase chain reaction -- FACS fluorescence-activated cell sorting -- X1, X2 FACS-defined, X-ray sensitive cell populations 1 and 2 -- Xin FACS-defined, X-ray insensitive cell population -- PBR pluripotency based regeneration -- CLOUD-PSPC Continuum of Low-primed UnDifferentiated Planarian Stem/Progenitor Cell -- cNeoblasts clonogenic neoblasts -- dsRNA long double stranded RNA -- PIC planarian immobilization chip -- BrdU bromodeoxyuridin; Neoblast -- Potency state transitions -- Stem cell heterogeneity -- CLOUD -- Badlands landscape -- Live cell tracking; Cytology -- Periodicals; Developmental biology -- Periodicals; 571.6
• DOI: 10.1016/j.semcdb.2018.04.012
• Languages: English
• ISSNs: 1084-9521

Abstract

Graphical abstract: The CLOUD-badlands landscape. Lineage specification is a continuous process, where cells gradually acquire features of multiple commitment. This counterposes with the rigid pyramidal organization of discrete progenitor cells, rather suggesting a Continuum of LOw-primed UnDifferentiated Planarian Stem/Progenitor Cells (CLOUD-PSPCs) that can plastically retune their fate commitment. Abstract: In planarians, pluripotency can be studied in vivo in the adult animal, making these animals a unique model system where pluripotency-based regeneration (PBR)—and its therapeutic potential—can be investigated. This review focuses on recent findings to build a cloud model of fate restriction likelihood for planarian stem and progenitor cells. Recently, a computational approach based on functional and molecular profiling at the single cell level was proposed for human hematopoietic stem cells. Based on data generated both in vivo and ex vivo, we hypothesized that planarian stem cells could acquire multiple direction lineage biases, following a "badlands" landscape. Instead of a discrete tree-like hierarchy, where the potency of stem/progenitor cells reduces stepwise, we propose a Continuum of LOw-primed UnDifferentiated Planarian Stem/Progenitor Cells (CLOUD-PSPCs). Every subclass of neoblast/progenitor cells is a cloud of likelihood, as the single cell transcriptomics data indicate. The CLOUD-HSPCs concept was substantiated by in vitro data from cell culture; therefore, to confirm the CLOUD-PSPCs model, the planarian community needs to develop new tools, like live cell tracking. Future studies will allow a deeper understanding of PBR in planarian, and the possible implications for regenerative therapies in human.