Project description:Effective tissue regeneration requires cells to perceive the surrounding context and make internal state adaptations that enable context-dependent fate changes in time and space, but the mechanisms underlying this complex process remain unclear. Here, transcriptom sequencing was used for study neuroendocrine control of planarian regneration
Project description:Regeneration is the regrowth of damaged tissues or organs, a vital mechanism in response to damages from primitive organisms to higher mammals. Planarian possesses active whole-body regenerative capability owning to its vast reservoir of adult stem cells, neoblasts, providing an ideal model to delineate the underlying mechanisms for regeneration. RNA N6-methyladenosine (m6A) modification participates in many biological processes, including stem cell self-renewal and differentiation, in particular the regeneration of hematopoietic stem cells and axons. However, how m6A controls regeneration at the whole-organism level remains largely unknown. Here, we demonstrate that the depletion of m6A methyltransferase regulatory subunit wtap abolishes planarian regeneration, potentially through regulating genes related to cell-cell communication and cell cycle. Single-cell RNA-seq (scRNA-seq) analysis unveils that the wtap knockdown induces a unique type of neural progenitor-like cells (NP-like cells), characterized by specific expression of the cell-cell communication ligand grn. Intriguingly, the depletion of m6A-modified transcripts grn/cdk9 (or cdk7) axis rescues the defective regeneration of planarian caused by wtap knockdown. Overall, our study reveals an indispensable role of m6A modification in regulating whole-organism regeneration.
Project description:Variability of regenerative potential among animals has long perplexed biologists. Based on their amazing regenerative abilities, planarians have become important models for understanding the molecular basis of regeneration; however, planarian species with limited regenerative abilities are also found. Despite the importance of understanding the differences between closely related, regenerating and non-regenerating organisms, few studies have focused on the evolutionary loss of regeneration, and the molecular mechanisms leading to such regenerative loss remain obscure. Here we examine Procotyla fluviatilis, a planarian with restricted ability to replace missing tissues, utilizing next-generation sequencing to define the gene expression programs active in regeneration-permissive and regeneration-deficient tissues. We found that Wnt signaling is aberrantly activated in regeneration-deficient tissues. Remarkably, down-regulation of canonical Wnt signaling in regeneration-deficient regions restores regenerative abilities: blastemas form and new heads regenerate in tissues that normally never regenerate. This work reveals that manipulating a single signaling pathway can reverse the evolutionary loss of regenerative potential. RNA-seq experiments to identify gene expression changes following amputation in body regions with variable regenerative potential. Adult Procotyla fluviatilis were amputated at sites either anterior or posterior to the pharynx. After 24 hours post-amputation, tissues near the amputation site were excised and RNA was extracted. Similar tissues were excised from uncut control animals. Samples were processed for RNA-seq using Illumina procedures. We generated a de novo P. fluviatilis transcriptome and used RNA sequencing (RNA-seq) to characterize transcripts from excised tissue fragments in Reg+ and Reg- body regions 24 hours post-amputation. We performed parallel analyses on tissues excised from intact animals at identical body regions to account for regional differences in transcripts, thereby identifying changes resulting from amputation. Samples A1-A3 = Regeneration-proficient (Reg+) tissue excision 24 hours after amputation. Samples B1-B3 = Tissue excision from regeneration-proficient (Reg+) region but not amputated. Samples C1-C3 = Tissue excision from regeneration-deficient (Reg-) tissues 24 hours after amputation. Samples D1, D3-D4 = Tissue excision from regeneration-deficient (Reg-) region that was not amputated.
Project description:The fundamental of regeneration process of invertebrates involves the renewal, differentiation and reprogramming of stem cell in an orchestrated manner. It has been known that N6-methyladenosine (m6A) regulates stem cell renewal and differentiation. It is still unclear if m6A is crucial for the regeneration at whole-organism level. Here, we demonstrate that wtap knockdown mediated m6A depletion impairs planarian regeneration upon amputation. The cell cycle related genes displayed decreased m6A while increased expression levels in response to wtap knockdown. The m6A depletion induced phenotypes can be rescued by double-knocking down these genes together with wtap, suggesting that m6A-mediated cell cycle controls planarian regeneration. Further analysis combining the single-cell sequencing unveils a unique neuronal progenitor-like cell type, named NCC and characterized by specific expression of grn, which is indispensable for neuroregeneration. Overall, our study uncovered an essential role of wtap-mediated m6A modification in regulating stem cell population dynamics and homeostasis in terms of general-body regeneration.
Project description:The fundamental of regeneration process of invertebrates involves the renewal, differentiation and reprogramming of stem cell in an orchestrated manner. It has been known that N6-methyladenosine (m6A) regulates stem cell renewal and differentiation. It is still unclear if m6A is crucial for the regeneration at whole-organism level. Here, we demonstrate that wtap knockdown mediated m6A depletion impairs planarian regeneration upon amputation. The cell cycle related genes displayed decreased m6A while increased expression levels in response to wtap knockdown. The m6A depletion induced phenotypes can be rescued by double-knocking down these genes together with wtap, suggesting that m6A-mediated cell cycle controls planarian regeneration. Further analysis combining the single-cell sequencing unveils a unique neuronal progenitor-like cell type, named NCC and characterized by specific expression of grn, which is indispensable for neuroregeneration. Overall, our study uncovered an essential role of wtap-mediated m6A modification in regulating stem cell population dynamics and homeostasis in terms of general-body regeneration.