Antioxidant Small Molecule Compound Chrysin Promotes the Self-Renewal of Hematopoietic Stem Cells.

Yinghui Li,Ming Yang,Yingdai Gao,Wenshan Zhang,Mei He,Yafang Li,Jingjing Yin,Jiali Gu,Yahui Ding,Shiqi Xu

doi:10.3389/fphar.2020.00399

Abstract

There is an increasing demand for the expansion of functional human hematopoietic stem cells (hHSCs) for various clinical applications. Based on our primary screening of antioxidant small molecule compounds library, a small molecule compound C2968 (chrysin) was identificated to expand cord blood CD34+ cells in vitro. Then we further verified the optimum concentration and explored its effect on hHSCs phenotype and biological function. C2968 could significantly increase the proportion and absolute number of CD34+CD38−CD49f+ and CD34+CD38−CD45RA−CD90+ cells under 2.5 μM. Furthermore, the total number of colony-forming units and the frequency of LT-HSCs in C2968-treated group were significantly higher than control, indicating the multipotency and long-term activity of hematopoietic stem and progenitor cells were sustained. Additionally, C2968 treatment could maintain transplantable HSCs that preserve balanced multilineage potential and promote rapid engraftment after transplantation in immunodeficient (NOG) mice. Mechanistically, the activity of chrysin might be mediated through multiple mechanisms namely delaying HSC differentiation, inhibiting ROS-activated apoptosis, and modulating of cyclin-dependent kinase inhibitors. Overall, chrysin showed good ex vivo expansion effect on hHSCs, which could maintain the self-renewal and multilineage differentiation potential of hHSCs. Through further research on its antioxidant mechanism, it may become a promising tool for further fundamental research and clinical umbilical cord blood transplantation of hHSCs.

Highlights

Hematopoietic stem cells (HSCs) are a rare population of cells characterized by their ability to selfrenew and differentiate into multilineages in blood system to maintain adult hematopoiesis
To investigate the optimum concentration of C2968, primary human CD34+ cells isolated from umbilical cord blood (UCB) were seeded into 96-well plates (1 × 104 cells per well) in expansion medium supplemented with SCF, TPO, and Flt3L
We identified C2968 as a candidate promoter of hematopoietic stem and progenitor cells (HSPCs) self-renewal, with effective concentrations of 0.5 to 10 μM when tested for its ability to stimulate the expansion of a more primitive HSPC populations, CD34+CD49f+ cells

Summary

Introduction

Hematopoietic stem cells (HSCs) are a rare population of cells characterized by their ability to selfrenew and differentiate into multilineages in blood system to maintain adult hematopoiesis. Less than half of the patients without a suitable related human leukocyte antigen (HLA)matched donor can find an HLA-matched unrelated donor (Gragert et al, 2014) For these patients, umbilical cord blood (UCB) has become an important HSC source for allogeneic HSCT (Milano et al, 2016).The much lower immunogenicity of UCB enables transplantation despite antigen mismatch. Recent studies have concentrated on applying small molecule compounds, which are gradually becoming a valuable tool for regulating the fate of stem cells They have the virtues of simple operation, rapid and reversible effects, diverse concentrations and structures, and rapid highthroughput screening based on phenotype (Li et al, 2012; Zhang and Gao, 2016). Our group has focused on drug screening for HSC manipulation, especially for safe expansion of HSC

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