Polarization and Migration of Hematopoietic Stem and Progenitor Cells Rely on the RhoA/ROCK I Pathway and an Active Reorganization of the Microtubule Network

• Published in: The Journal of biological chemistry 2010-10, Vol.285 (41), p.31661-31671
• Main Authors: Fonseca, Ana-Violeta, Freund, Daniel, Bornhäuser, Martin, Corbeil, Denis
• Format: Article
• Language: English
• Subjects: AC133 Antigen; Amides - pharmacology; Antigens, CD - genetics; Antigens, CD - metabolism; Cell Biology; Cell Migration; Cell Motility; Cell Movement - drug effects; Cell Movement - physiology; Cell Polarity - drug effects; Cell Polarity - physiology; Cells, Cultured; Cytoskeletal Proteins - genetics; Cytoskeletal Proteins - metabolism; Enzyme Inhibitors - pharmacology; Gene Knockdown Techniques; Glycoproteins - genetics; Glycoproteins - metabolism; Hematopoietic Stem Cells - cytology; Hematopoietic Stem Cells - metabolism; Humans; Membrane Biology; Microtubules - genetics; Microtubules - metabolism; Peptides - genetics; Peptides - metabolism; Pyridines - pharmacology; Rho; rho-Associated Kinases - genetics; rho-Associated Kinases - metabolism; rhoA GTP-Binding Protein - antagonists & inhibitors; rhoA GTP-Binding Protein - genetics; rhoA GTP-Binding Protein - metabolism; Stem Cell; Stromal Cell
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M110.145037

Understanding the physiological migration of hematopoietic progenitors is important, not only for basic stem cell research, but also in view of their therapeutic relevance. Here, we investigated the role of the Rho kinase pathway in the morphology and migration of hematopoietic progenitors using an ex vivo co-culture consisting of human primary CD34+ progenitors and mesenchymal stromal cells. The addition of the Rho kinase inhibitor Y-27632 led to the abolishment of the uropod and microvillar-like structures of hematopoietic progenitors, concomitant with a redistribution of proteins found therein (prominin-1 and ezrin). Y-27632-treated cells displayed a deficiency in migration. Time-lapse video microscopy revealed impairment of the rear pole retraction. Interestingly, the knockdown of ROCK I, but not ROCK II, using RNA interference (RNAi) was sufficient to cause the referred morphological and migrational changes. Unexpectedly, the addition of nocodazole to either Y-27632- or ROCK I RNAi-treated cells could restore their polarized morphology and migration suggesting an active role for the microtubule network in tail retraction. Finally, we could demonstrate using RNAi that RhoA, the upstream regulator of ROCK, is involved in these processes. Collectively, our data provide new insights regarding the role of RhoA/ROCK I and the microtubules in the migration of stem cells.