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Abstract Adult pluripotent stem cells are found in diverse animals, including cnidarians, acoels, and planarians, and confer remarkable abilities such as whole-body regeneration. The mechanisms by which these pluripotent stem cells orchestrate the replacement of all lost cell types, however, remains poorly understood. Underlying heterogeneity within the stem cell populations of these animals is often obscured when focusing on certain tissue types or life history stages, which tend to have indistinguishable spatial expression patterns of stem cell marker genes. Here, we focus on the adult pluripotent stem cells (i-cells) ofHydractinia symbiolongicarpus, a colonial marine cnidarian with distinct polyp types and stolonal tissue. Recently, a single-cell expression atlas was generated forH. symbiolongicarpuswhich revealed two distinct clusters with i-cell signatures, potentially representing heterogeneity within this species’ stem cell population. Considering this finding, we investigated eight new putative stem cell marker genes from the atlas including five expressed in both i-cell clusters (Pcna,Nop58,Mcm4,Ubr7, andUhrf1) and three expressed in one cluster or the other (Pter, FoxQ2-like,andZcwpw1). We characterized their expression patterns in various contexts–feeding and sexual polyps, juvenile feeding polyps, stolon, and during feeding polyp head regeneration–revealing context-dependent gene expression patterns and a transcriptionally dynamic i-cell population. We uncover previously unknown differences within the i-cell population ofHydractiniaand demonstrate that its colonial nature serves as an excellent system for investigating and visualizing heterogeneity in pluripotent stem cells.
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This content will become publicly available on December 1, 2025
Annelid adult cell type diversity and their pluripotent cellular origins
Abstract Many annelids can regenerate missing body parts or reproduce asexually, generating all cell types in adult stages. However, the putative adult stem cell populations involved in these processes, and the diversity of cell types generated by them, are still unknown. To address this, we recover 75,218 single cell transcriptomes of the highly regenerative and asexually-reproducing annelidPristina leidyi. Our results uncover a rich cell type diversity including annelid specific types as well as novel types. Moreover, we characterise transcription factors and gene networks that are expressed specifically in these populations. Finally, we uncover a broadly abundant cluster of putative stem cells with a pluripotent signature. This population expresses well-known stem cell markers such asvasa,piwiandnanoshomologues, but also shows heterogeneous expression of differentiated cell markers and their transcription factors. We find conserved expression of pluripotency regulators, including multiple chromatin remodelling and epigenetic factors, inpiwi+cells. Finally, lineage reconstruction analyses reveal computational differentiation trajectories frompiwi+cells to diverse adult types. Our data reveal the cell type diversity of adult annelids by single cell transcriptomics and suggest that apiwi+ cell population with a pluripotent stem cell signature is associated with adult cell type differentiation.
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- Award ID(s):
- 1923429
- PAR ID:
- 10563685
- Publisher / Repository:
- Nature Communications
- Date Published:
- Journal Name:
- Nature Communications
- Volume:
- 15
- Issue:
- 1
- ISSN:
- 2041-1723
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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