Protein tyrosine phosphatase-σ regulates hematopoietic stem cell-repopulating capacity. J Clin Invest 2015 Jan;125(1):177-82
Date
11/22/2014Pubmed ID
25415437Pubmed Central ID
PMC4382260DOI
10.1172/JCI77866Scopus ID
2-s2.0-84920461717 (requires institutional sign-in at Scopus site) 22 CitationsAbstract
Hematopoietic stem cell (HSC) function is regulated by activation of receptor tyrosine kinases (RTKs). Receptor protein tyrosine phosphatases (PTPs) counterbalance RTK signaling; however, the functions of receptor PTPs in HSCs remain incompletely understood. We found that a receptor PTP, PTPσ, was substantially overexpressed in mouse and human HSCs compared with more mature hematopoietic cells. Competitive transplantation of bone marrow cells from PTPσ-deficient mice revealed that the loss of PTPσ substantially increased long-term HSC-repopulating capacity compared with BM cells from control mice. While HSCs from PTPσ-deficient mice had no apparent alterations in cell-cycle status, apoptosis, or homing capacity, these HSCs exhibited increased levels of activated RAC1, a RhoGTPase that regulates HSC engraftment capacity. shRNA-mediated silencing of PTPσ also increased activated RAC1 levels in wild-type HSCs. Functionally, PTPσ-deficient BM cells displayed increased cobblestone area-forming cell (CAFC) capacity and augmented transendothelial migration capacity, which was abrogated by RAC inhibition. Specific selection of human cord blood CD34⁺CD38⁻CD45RA⁻lin⁻ PTPσ⁻ cells substantially increased the repopulating capacity of human HSCs compared with CD34⁺CD38⁻CD45RA⁻lin⁻ cells and CD34⁺CD38⁻CD45RA⁻lin⁻PTPσ⁺ cells. Our results demonstrate that PTPσ regulates HSC functional capacity via RAC1 inhibition and suggest that selecting for PTPσ-negative human HSCs may be an effective strategy for enriching human HSCs for transplantation.
Author List
Quarmyne M, Doan PL, Himburg HA, Yan X, Nakamura M, Zhao L, Chao NJ, Chute JPAuthor
Heather A. Himburg PhD Professor in the Radiation Oncology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AnimalsCells, Cultured
Hematopoietic Stem Cell Transplantation
Hematopoietic Stem Cells
Humans
Mice, Inbred BALB C
Mice, Inbred C57BL
Mice, Inbred NOD
Neuropeptides
Receptor-Like Protein Tyrosine Phosphatases, Class 2
Transendothelial and Transepithelial Migration
rac1 GTP-Binding Protein
