Atypical PKC-ζ regulates SDF-1–mediated migration and development of human CD34+ progenitor cells
Isabelle Petit, … , Ronen Alon, Tsvee Lapidot
Isabelle Petit, … , Ronen Alon, Tsvee Lapidot
Published January 3, 2005
Citation Information: J Clin Invest. 2005;115(1):168-176. https://doi.org/10.1172/JCI21773.
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Article Stem cells

Atypical PKC-ζ regulates SDF-1–mediated migration and development of human CD34+ progenitor cells

Abstract

The chemokine stromal cell–derived factor–1 (SDF-1) and its receptor, CXCR4, play a major role in migration, retention, and development of hematopoietic progenitors in the bone marrow. We report the direct involvement of atypical PKC-ζ in SDF-1 signaling in immature human CD34+-enriched cells and in leukemic pre-B acute lymphocytic leukemia (ALL) G2 cells. Chemotaxis, cell polarization, and adhesion of CD34+ cells to bone marrow stromal cells were found to be PKC-ζ dependent. Overexpression of PKC-ζ in G2 and U937 cells led to increased directional motility to SDF-1. Interestingly, impaired SDF-1–induced migration of the pre-B ALL cell line B1 correlated with reduced PKC-ζ expression. SDF-1 triggered PKC-ζ phosphorylation, translocation to the plasma membrane, and kinase activity. Furthermore we identified PI3K as an activator of PKC-ζ, and Pyk-2 and ERK1/2 as downstream targets of PKC-ζ. SDF-1–induced proliferation and MMP-9 secretion also required PKC-ζ activation. Finally, we showed that in vivo engraftment, but not homing, of human CD34+-enriched cells to the bone marrow of NOD/SCID mice was PKC-ζ dependent and that injection of mice with inhibitory PKC-ζ pseudosubstrate peptides resulted in mobilization of murine progenitors. Our results demonstrate a central role for PKC-ζ in SDF-1–dependent regulation of hematopoietic stem and progenitor cell motility and development.

Authors

Isabelle Petit, Polina Goichberg, Asaf Spiegel, Amnon Peled, Chaya Brodie, Rony Seger, Arnon Nagler, Ronen Alon, Tsvee Lapidot

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Figure 1

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Effect of PKC inhibitors on SDF-1–induced migration. CD34+ cells (A and ...
Effect of PKC inhibitors on SDF-1–induced migration. CD34+ cells (A and C) or G2 cells (B and D) were preincubated for 30 minutes with PKC inhibitors staurosporine (ST), GF 109203X (GF), or indicated concentrations of chelerythrine chloride (CC) (A and B) or for 1 hour with 10 μM of either PS-α/β, PS-ε, or indicated concentrations of PS-ζ peptides (C and D). SDF-1–induced migration was determined by the transwell assay. Migration of control cells to medium only (–) and to SDF-1 is indicated. Data show average ± SD of at least 3 experiments; *P < 0.05. (E) G2 and U937 cells transfected with GFP–PKC-ζ–expressing plasmid were subjected to transwell migration to SDF-1. Where indicated (white bars), transfected cells were preincubated for 1 hour with PS-ζ peptides (10 μM). Fold increase migration represents the ratio of the number of GFP–PKC-ζ migrating cells to the number of migrating mock-transfected cells. Insert indicates the percentage of GFP+ G2 cells in the migrating (Migr.) and nonmigrating (Nonmigr.) cell populations. Results are average ± SD of 2 independent experiments for each cell line; *P < 0.05.