The sinusoidal hematopoietic niche is formed by Jam1a via Notch signaling in the zebrafish kidney.

The zebrafish is a unique model to understand hematopoietic niches as hematopoietic stem/progenitor cells are maintained in the kidney. However, little is known about which cell types in the kidney play a role in hematopoietic niches. Here, we demonstrate that the sinusoidal endothelium is an essential and conserved niche component in the zebrafish kidney.

Inhibition of Canonical Wnt Signaling Promotes Ex Vivo Maintenance and Proliferation of Hematopoietic Stem Cells in Zebrafish.

The maintenance and proliferation of hematopoietic stem cells (HSCs) are tightly regulated by their niches in the bone marrow. The analysis of niche cells or stromal cell lines that can support HSCs has facilitated the finding of novel supporting factors for HSCs. Despite large efforts in the murine bone marrow; however, HSC expansion is still difficult ex vivo, highlighting the need for new approaches to elucidate the molecular elements that regulate HSCs.

Uptake of osteoblast-derived extracellular vesicles promotes the differentiation of osteoclasts in the zebrafish scale.

Differentiation of osteoclasts (OCs) from hematopoietic cells requires cellular interaction with osteoblasts (OBs). Due to the difficulty of live-imaging in the bone, however, the cellular and molecular mechanisms underlying intercellular communication involved in OC differentiation are still elusive. Here, we develop a fracture healing model using the scale of trap:GFP; osterix:mCherry transgenic zebrafish to visualize the interaction between OCs and OBs.

Enrichment of hematopoietic stem/progenitor cells in the zebrafish kidney.

Hematopoietic stem cells (HSCs) maintain the entire blood system throughout life and are utilized in therapeutic approaches for blood diseases. Prospective isolation of highly purified HSCs is crucial to understand the molecular mechanisms underlying regulation of HSCs. The zebrafish is an elegant genetic model for the study of hematopoiesis due to its many unique advantages.