Rescue of hematopoietic stem/progenitor cells formation in plcg1 zebrafish mutant

Karine F Ferri-Lagneau,Jamil Haider,Tinchung Leung,Shengmin Sang

doi:10.1038/s41598-018-36338-8

Abstract

Hematopoietic stem/progenitor cells (HSPC) in zebrafish emerge from the aortic hemogenic endothelium (HE) and migrate towards the caudal hematopoietic tissue (CHT), where they expand and differentiate during definitive hematopoiesis. Phospholipase C gamma 1 (Plcγ1) has been implicated for hematopoiesis in vivo and in vitro and is also required to drive arterial and HSPC formation. Genetic mutation in plcg1−/− (y10 allele) completely disrupts the aortic blood flow, specification of arterial fate, and HSPC formation in zebrafish embryos. We previously demonstrated that ginger treatment promoted definitive hematopoiesis via Bmp signaling. In this paper, we focus on HSPC development in plcg1−/− mutants and show that ginger/10-gingerol (10-G) can rescue the expression of arterial and HSPC markers in the HE and CHT in plcg1−/− mutant embryos. We demonstrate that ginger can induce scl/runx1 expression, and that rescued HE fate is dependent on Bmp and Notch. Bmp and Notch are known to regulate nitric oxide (NO) production and NO can induce hematopoietic stem cell fate. We show that ginger produces a robust up-regulation of NO. Taken together, we suggest in this paper that Bmp, Notch and NO are potential players that mediate the effect of ginger/10-G for rescuing the genetic defects in blood vessel specification and HSPC formation in plcg1−/− mutants. Understanding the molecular mechanisms of HSPC development in vivo is critical for understanding HSPC expansion, which will have a positive impact in regenerative medicine.

Highlights

During vascular development, endothelial progenitors give rise to a network of blood vessels including arteries and veins
We choose two different timings using the myb marker because around 1 dpf, the myb + cells originally emerge along the dorsal aorta (DA), and around 2 dpf, they migrate to the caudal hematopoietic tissue (CHT) region
Further supporting the above finding, we demonstrate that bmp7a is expressed in the DA of WT siblings at 1–2 dpf stage; bmp7a expression is rescued in the restored DA of ginger-treated plcg1−/−embryos (Fig. 1D)

Summary

Introduction

Endothelial progenitors give rise to a network of blood vessels including arteries and veins. Zebrafish HSPCs undergo EHT around 30 to 35 hour-post-fertilization (hpf)[13] from the luminal side of the dorsal aorta These cells directly emerge from aortic endothelium[13,14] and migrate through the sub-aortic space[13] to the caudal hematopoietic tissue (CHT). The CVP provides a microenvironment for interaction of the developing HSPCs with secreted factors and cytokines necessary for the HSPCs to be instructed and to differentiate[15,21,22] In this hematopoietic microenvironment, HSPCs undergo extensive proliferation and further migrate to seed the definitive hematopoietic organs, the thymus and kidney marrow, giving rise to many blood lineages[20,23]. Using a NO scavenger, we show that ginger-induced NO production is required for rescuing the expression of arterial and HSPC markers and blood circulation

Methods

Results

Conclusion