fluorescent-situ-hybridization-5-ethynyl-2-deoxyuridine-labeling-for

Fluorescent <em>In Situ</em> Hybridization and 5-Ethynyl-2'-Deoxyuridine Labeling for Stem-Like Cells in the Hydrozoan Jellyfish <em>Cladonema pacificum</em>

Cnidarians, including sea anemones, corals, and jellyfish, exhibit diverse morphology and lifestyles that are manifested in sessile polyps and ...

The University of Tokyo

the university of tokyo

Tissue remodeling involves collective cell movement, and cell proliferation and apoptosis are observed in both development and disease. Apoptosis and proliferation are considered to be closely correlated, but little is known about their coordinated regulation in physiological tissue remodeling in vivo. The replacement of larval abdominal epidermis with adult epithelium in Drosophila pupae is a simple model of tissue remodeling. During this process, larval epidermal cells (LECs) undergo apoptosis and are replaced by histoblasts, which are adult precursor cells. By analyzing caspase activation at the single-cell level in living pupae, we found that caspase activation in LECs is induced at the LEC/histoblast boundary, which expands as the LECs die. Manipulating histoblast proliferation at the LEC/histoblast boundary, either genetically or by UV illumination, indicated that local interactions with proliferating histoblasts triggered caspase activation in the boundary LECs. Finally, by monitoring the spatiotemporal dynamics of the S/G₂/M phase in histoblasts in vivo, we found that the transition from S/G₂ phases is necessary to induce nonautonomous LEC apoptosis at the LEC/histoblast boundary. The replacement boundary, formed as caspase activation is regulated locally by cell-cell communication, may drive the dynamic orchestration of cell replacement during tissue remodeling.

Nonautonomous apoptosis is triggered by local cell cycle progression during epithelial replacement in Drosophila.

Caspases, which constitute a family of cysteine proteases, are highly conserved in multicellular organisms and function as a central player in apoptosis. The detection of apoptosis is intrinsically difficult because dying cells are rapidly removed from tissues by phagocytosis. Thus, the development of a method for detecting caspase activation is critical for the in vivo study of apoptosis. In this chapter, we describe a genetically encoded fluorescent probe for live imaging of caspase activation. 

In vivo monitoring of caspase activation using a fluorescence resonance energy transfer-based fluorescent probe.

Adult tissues in Metazoa dynamically remodel their structures in response to environmental challenges including sudden injury, pathogen infection, and nutritional fluctuation, while maintaining quiescence under homoeostatic conditions. This characteristic, hereafter referred to as adult tissue plasticity, can prevent tissue dysfunction and improve the fitness of organisms in continuous and/or severe change of environments. With its relatively simple tissue structures and genetic tools, studies using the fruit fly  have provided insights into molecular mechanisms that control cellular responses, particularly during regeneration and nutrient adaptation. In this review, we present the current understanding of cellular mechanisms, stem cell proliferation, polyploidization, and cell fate plasticity, all of which enable adult tissue plasticity in various  adult organs including the midgut, the brain, and the gonad, and discuss the organismal strategy in response to environmental changes and future directions of the research.

Article	Year
Nonautonomous apoptosis is triggered by local cell cycle progression during epithelial replacement in Drosophila. Molecular and cellular biology\| PubMed ID: 21482673	2011
In vivo monitoring of caspase activation using a fluorescence resonance energy transfer-based fluorescent probe. Methods in enzymology\| PubMed ID: 24974295	2014
Cellular mechanisms underlying adult tissue plasticity in . Fly\| PubMed ID: 35470772	2022

Yu-ichiro Nakajima

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