Nakajima, Y.-i. | bioRxiv Science

bioRxiv2025

Xrp1 drives damage-induced cellular plasticity of enteroendocrine cells in the adult Drosophila midgut

Cellular plasticity, the ability of a differentiated cell to adopt another phenotypic identity, is restricted under basal conditions, but can be elicited upon damage to facilitate regeneration. Such damage-induced cellular plasticity restores homeostasis and prevents pathology, yet its underlying molecular basis remains largely unexplored. Here, we reported damage-induced cellular plasticity of secretory enteroendocrine cells (EEs) in the adult Drosophila midgut. We found that ionizing radiation enhanced EE plasticity such that it promoted EEs to dedifferentiate into ISCs and subsequently re-differentiate towards ECs. We identified that radiation induced the production of a stress-inducible transcription factor Xrp1 in EE lineages, and its upregulation was necessary for EE plasticity. Single-cell RNA sequencing of guts with EE-specific Xrp1 overexpression revealed ectopic expression of progenitor-specific genes in EEs, which was necessary for Xrp1 to drive EE plasticity. Our work provides a mechanistic framework for understanding cellular plasticity and suggests its potential role in damage-induced responses.

cell biology↗

bioRxiv2022

siRNA-mediated gene knockdown via electroporation in hydrozoan jellyfish embryos

As the sister group to bilaterians, cnidarians stand in a unique phylogenetic position that provides insight into evolutionary aspects of animal development, physiology, and behavior. While cnidarians are classified into two types, sessile polyps and free-swimming medusae, most studies at the cellular and molecular levels have been conducted on representative polyp-type cnidarians and have focused on establishing techniques of genetic manipulation. Recently, gene knockdown by delivery of short hairpin RNAs into eggs via electroporation has been introduced in two polyp-type cnidarians, Nematostella vectensis and Hydractinia symbiolongicarpus, enabling systematic loss-of-function experiments. By contrast, current methods of genetic manipulation for most medusa-type cnidarians, or jellyfish, are quite limited, except for Clytia hemisphaerica, and reliable techniques are required to interrogate function of specific genes in different jellyfish species. Here, we present a method to knock down target genes by delivering small interfering RNA (siRNA) into fertilized eggs via electroporation, using the hydrozoan jellyfish, Clytia hemisphaerica and Cladonema paciificum. We show that siRNAs targeting endogenous GFP1 and Wnt3 in Clytia efficiently knock down gene expression and result in known planula phenotypes: loss of green fluorescence and defects in axial patterning, respectively. We also successfully knock down endogenous Wnt3 in Cladonema by siRNA electroporation, which circumvents the technical difficulty of microinjecting small eggs. Wnt3 knockdown in Cladonema causes gene expression changes in axial markers, suggesting a conserved Wnt/{beta}-catenin-mediated pathway that controls axial polarity during embryogenesis. Our gene-targeting siRNA electroporation method is applicable to other animals, including and beyond jellyfish species, and will facilitate the investigation and understanding of myriad aspects of animal development.

developmental biology↗