Single-Cell Profiling and SCOPE-Seq Reveal Lineage Dynamics of Adult Ventricular-Subventricular Zone Neurogenesis and NOTUM as a Key Regulator

Abstract

SUMMARY In the adult ventricular-subventricular zone (V-SVZ), neural stem cells (NSCs) generate new olfactory bulb (OB) neurons and glia throughout life. To map adult neuronal lineage progression, we profiled >56,000 V-SVZ and OB cells by single-cell RNA sequencing (scRNA-seq). Our analyses reveal the molecular diversity of OB neurons, including fate-mapped neurons, lineage progression dynamics, and an NSC intermediate enriched for Notum , which encodes a secreted WNT antagonist. SCOPE-seq technology, which links live-cell imaging with scRNA-seq, uncovers cell-size transitions during NSC differentiation and preferential NOTUM binding to proliferating neuronal precursors. Consistently, application of NOTUM protein in slice cultures and pharmacological inhibition of NOTUM in slice cultures and in vivo demonstrated that NOTUM negatively regulates V-SVZ proliferation. Timely, context-dependent neurogenesis demands adaptive signaling among neighboring progenitors. Our findings highlight a critical regulatory state during NSC activation marked by NOTUM, which attenuates WNT-stimulated proliferation in NSC progeny.

Neural stem cell pools in the vertebrate adult brain: Homeostasis from cell‐autonomous decisions or community rules?

“…Understanding the molecular mechanisms underlying these heterogeneities and their coordination remains a fundamental issue. Single cell transcriptome profiling provides a first step toward this goal, and was conducted in a number of studies in the SEZ, [ 7,8,12,39–41 ] SGZ [ 6,42,43 ] and zebrafish Dm, [ 44,45 ] from micro‐dissected tissue or FACS‐sorted cells, including NSCs, committed progenitors, neurons, and niche cells. While NSCs could be clustered into distinct transcriptome‐based subgroups, pseudo‐time analyses highlight that these subgroups hierarchically progress from quiescent NSCs to neurons, and are therefore dominated by broad changes in activation or commitment.…”

Choroid Plexus: The Orchestrator of Long-Range Signalling Within the CNS

“…Interestingly, a regionalized and sex-dependent pattern of expression was also associated with genes encoding various receptors and secreted molecules [179]. Notum, a secreted extracellular suppressor of Wnt ligands, displays SVZ-subdomain-specific expression [180], raising an interesting possibility of spatially-restricted regulation of Wnt pathway activation via localized deactivation of Wnt ligands, which were previously shown to be secreted from the CP into CSF [62,111]. Corroborating these findings, transthyretin (TTR), a thyroid hormone transporter predominantly produced by the CP [112], exhibits a gender-specific role in the control of neurogenesis in the SVZ that is restricted to a specific subdomain of the SVZ [181], which is in line with the gender-based differences in CP-derived TTR levels detected in the CSF [71,182].…”

Integrating single-cell RNA-seq and imaging with SCOPE-seq2

“…The improvements to SCOPE-seq2 have enabled applications in primary cells isolated from complex tissues, which are typically more challenging to profile by scRNA-seq than cell lines grown in culture. In parallel with this study, we used SCOPE-seq2 to reveal cell size dynamics during adult neurogenesis in the mouse brain and identify the precise stage in neuronal differentiation where morphological changes associated with cell cycle entry occur 20 . In the same experiment, we also used SCOPE-seq2 with anti-NOTUM immunostaining to identify the cellular targets of NOTUM, an extracellular WNT antagonist that plays a crucial regulatory role in adult neurogenesis.…”