Search bioRxiv⌕ Search

bioRxiv · 10.1101/2023.05.10.540286

A wound-induced differentiation trajectory for neurons

Abstract

Animals capable of whole-body regeneration can replace any missing cell type and regenerate fully-functional new organs, de novo. The regeneration of a new brain requires the formation of diverse neuronal cell types and their assembly into an organized structure and correctly-wired circuits. Recent work in various regenerative animals has revealed transcriptional programs required for the differentiation of distinct neuronal subpopulations, however how these transcriptional programs are initiated upon amputation remains unknown. Here, we focused on the highly regenerative acoel worm, Hofstenia miamia, to study wound-induced transcriptional regulatory events that lead to the production of neurons. Footprinting analysis using chromatin accessibility data on an improved genome assembly revealed that binding sites for the NFY transcription factor complex were significantly bound during regeneration, showing a dynamic increase in binding within one hour upon amputation specifically in tail fragments, which will regenerate a new brain. Strikingly, NFY targets were highly enriched for genes with neuronal functional. Single-cell transcriptome analysis combined with functional studies identified sox4+stem cells as the likely progenitor population for multiple neuronal subtypes. Further, we found that wound-induced sox4 expression is likely under direct transcriptional control by NFY, uncovering a mechanism for how early wound-induced binding of a transcriptional regulator results in the initiation of a neuronal differentiation pathway. HighlightsO_LIA new chromosome-scale assembly for Hofstenia enables comprehensive analysis of transcription factor binding during regeneration C_LIO_LINFY motifs become dynamically bound by 1hpa in regenerating tail fragments, particularly in the loci of neural genes C_LIO_LIA sox4+ neural-specialized stem cell is identified using scRNA-seq C_LIO_LIsox4 is wound-induced and required for differentiation of multiple neural cell types C_LIO_LINFY regulates wound-induced expression of sox4 during regeneration C_LI

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Hulett, R. E., Gehrke, A. R., Gompers, A., Rivera-Lopez, C., Srivastava, M.. 2023-05-11. A wound-induced differentiation trajectory for neurons. https://doi.org/10.1101/2023.05.10.540286

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Hyaluronic acid dynamics are regulated by neural crest cells and NEDD4 in the developing cardiac outflow tract valves

The extracellular matrix (ECM) is essential for cardiac valve development, with hyaluronic acid (HA) playing a critical role in cardiac cushion formation. While HA is required for atrioventricular valve development, its role in semilunar valve formation remains poorly understood. The ubiquitin ligase NEDD4 is essential for cardiac outflow tract development, particularly within cardiac neural crest cells, however its role in semilunar valve development has been unexplored. Here, we demonstrate that neural crest-specific deletion of NEDD4 in mice disrupts outflow tract valve development, resulting in abnormal leaflet number and morphology. Analysis of valve ECM revealed a specific reduction in HA within the neural crest-derived valve mesenchyme, while other ECM components such as fibronectin and versican remained unaffected. In contrast, deletion of NEDD4 in endocardium-derived valve mesenchyme did not alter HA abundance. Using NEDD4-deficient neural crest cells, we further demonstrate a cell-autonomous requirement for NEDD4 in regulating HA abundance, with in vitro evidence supporting impaired HA synthesis rather than increased turnover of HA in the ECM. Our findings identify a previously unrecognised role for NEDD4 in regulating HA synthesis in cardiac neural crest cells, revealing a cell-type-specific mechanism governing semilunar valve development and highlighting distinct cellular requirements for ECM regulation across cardiac valve populations.

developmental biology↗

Endogenous Mechanical Reporters Encode the Global Mechanical Landscape of Morphogenesis

Developmental systems usually comprise multiple genetically programmed morphogenetic events within a mechanically continuous environment, yet how individual processes interact and contribute to the overall mechanical landscape remains unknown. Here, we introduce the concept of mechanical reporter: endogenous tissues function as in situ probes of the embedded mechanical landscape. We exemplified cephalic furrow (CF) migration as a mechanical reporter in gastrulating Drosophila. Using optogenetics and genetics, we revealed that CF displacement reflects the combined effect of both force and tissue mechanical properties. By incorporating condition-specific mechanical landscape into a continuum minimal-response model, we developed a framework to quantitatively predict the reporter dynamics. Using different genetic mutants, we successfully decoded changes in the mechanical landscape from CF dynamics in gastrulating Drosophila. Overall, we established a predictive framework that uses CF dynamics to infer changes in the global mechanical landscape. Beyond this, the concept of mechanical reporter provides a general strategy for systematically understanding and decoding complex mechanical environments in living systems.

developmental biology↗

Dissecting human embryonic patterning during organogenesis reveals a rostral midline progenitor population for mesoendoderm induction

Understanding how human organogenesis is accomplished via intricate spatiotemporal patterning of organ primordia requires spatial atlases at cellular resolution. However, existing human embryo spatial atlases are built using sequencing-based platforms such as Stereo-seq, which have limited spatial resolution and blurred anatomical boundaries, leading to misclassification across adjacent cells. Here, we integrate in situ imaging-based transcriptomics (Xenium) with transcriptome-wide spatial profiling (Visium-HD) of Carnegie stages 9-12 embryos to delineate the patterning of core embryonic tissues at single-cell resolution, including the brain, spinal cord, somites, neural crest, notochord, heart, and gut tube. A new finding enabled by spatial single-cell resolution is the identification of rostral midline progenitors (RMPs), a cell population co-expressing SOX2, TBXT, and OTX2. Transcriptionally, RMPs are distinct from both neuromesodermal progenitors (NMPs) and prechordal mesoderm, and in vivo clonal barcoding in mice indicates that RMPs share a common developmental origin with rostral neural ectoderm. To interrogate their functional significance, we leveraged our spatial transcriptome data to recapitulate RMP-like cells from human pluripotent stem cells and showed that these cells can induce epiblast-like cells to acquire mesendodermal and endodermal fates, while themselves adopting an ectodermal fate consistent with their in vivo counterparts. This work provides a 3D, stage-resolved molecular cell atlas of tissue patterning in human embryo that serves as a reference for in vitro models.

developmental biology↗