EphB4 Expressing Stromal Cells Exhibit an Enhanced Capacity for Hematopoietic Stem Cell Maintenance. (23rd June 2015)

• Record Type: Journal Article
• Authors: Nguyen, Thao M.; Arthur, Agnieszka; Panagopoulos, Romana; Paton, Sharon; Hayball, John D.; Zannettino, Andrew C.W.; Purton, Louise E.; Matsuo, Koichi; Gronthos, Stan
• Is Part Of: Stem cells. Volume 33:Number 9(2015:Sep.)
• Page Start: 2838
• Page End: 2849
• Publication Date: 2015-06-23
• Subjects: Cloning -- Periodicals; Clone cells -- Periodicals; Stem cells -- Periodicals; Cell Differentiation -- Periodicals; Cell Division -- Periodicals; Clone Cells -- Periodicals; Hematopoietic Stem Cells -- Periodicals; Stem Cells -- Periodicals; 571.84
• DOI: 10.1002/stem.2069
• Languages: English
• ISSNs: 1066-5099

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The tyrosine kinase receptor, EphB4, mediates cross‐talk between stromal and hematopoietic populations during bone remodeling, fracture repair and arthritis, through its interactions with the ligand, ephrin‐B2. This study demonstrated that transgenic EphB4 mice (EphB4 Tg), over‐expressing EphB4 under the control of collagen type‐1 promoter, exhibited higher frequencies of osteogenic cells and hematopoietic stem/progenitor cells (HSC), correlating with a higher frequency of long‐term culture‐initiating cells (LTC‐IC), compared with wild type (WT) mice. EphB4 Tg stromal feeder layers displayed a greater capacity to support LTC‐IC in vitro, where blocking EphB4/ephrin‐B2 interactions decreased LTC‐IC output. Similarly, short hairpin RNA‐mediated EphB4 knockdown in human bone marrow stromal cells reduced their ability to support high ephrin‐B2 expressing CD34<sup>+</sup> HSC in LTC‐IC cultures. Notably, irradiated EphB4 Tg mouse recipients displayed enhanced bone marrow reconstitution capacity and enhanced homing efficiency of transplanted donor hematopoietic stem/progenitor cells relative to WT controls. Studies examining the expression of hematopoietic supportive factors produced by stromal cells indicated that CXCL12, Angiopoietin‐1, IL‐6, FLT‐3 ligand, and osteopontin expression were more highly expressed in EphB4 Tg stromal cells compared with WT controls. These findings indicate that EphB4 facilitates stromal‐mediated support of hematopoiesis, and constitute a novel component of the HSC niche. S<sc>tem</sc> C<sc>ells</sc><italic>2015;33:2838—2849</italic></p> </abstract>