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Macrophage-lineage cells are indispensable to immunity and physiology of all vertebrates. Amongst these, amphibians represent a key stage in vertebrate evolution and are facing decimating population declines and extinctions, in large part due to emerging infectious agents. While recent studies indicate that macrophages and related innate immune cells are critically involved during these infections, much remains unknown regarding the ontogeny and functional differentiation of these cell types in amphibians. Accordingly, in this review we coalesce what has been established to date about amphibian blood cell development (hematopoiesis), the development of key amphibian innate immune cells (myelopoiesis) and the differentiation of amphibian macrophage subsets (monopoiesis). We explore the current understanding of designated sites of larval and adult hematopoiesis across distinct amphibian species and consider what mechanisms may lend to these species-specific adaptations. We discern the identified molecular mechanisms governing the functional differentiation of disparate amphibian (chiefly Xenopus laevis) macrophage subsets and describe what is known about the roles of these subsets during amphibian infections with intracellular pathogens. Macrophage lineage cells are at the heart of so many vertebrate physiological processes. Thus, garnering greater understanding of the mechanisms responsible for the ontogeny and functionality of these cells in amphibians will lend to a more comprehensive view of vertebrate evolution.
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This content will become publicly available on November 1, 2025
Adeno-associated viral tools to trace neural development and connectivity across amphibians
Amphibians,byvirtueoftheirphylogeneticposition,provideinvaluableinsightsonnervoussystemevolution, development, and remodeling. The genetic toolkit for amphibians, however, remains limited. Recombinant adeno-associated viral vectors (AAVs) are a powerful alternative to transgenesis for labeling and manipulating neurons. Although successful in mammals,AAVshaveneverbeenshowntotransduceamphibiancells efficiently. We screened AAVs in three amphibian species—the frogs Xenopus laevis and Pelophylax bedriagae andthesalamanderPleurodeles waltl—and identified at least two AAV serotypes per speciesthat transduceneurons.Indevelopingamphibians,AAVslabeledgroupsofneuronsgeneratedatthesametimeduring development. In the mature brain, AAVrg retrogradely traced long-range projections. Our study introduces AAVs as a tool for amphibian research, establishes a generalizable workflow for AAV screening in new species, and expands opportunities for cross-species comparisons of nervous system development, function, and evolution.
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- PAR ID:
- 10573395
- Publisher / Repository:
- Developmental Cell
- Date Published:
- Journal Name:
- Developmental Cell
- ISSN:
- 1534-5807
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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