TY - JOUR

T1 - Mouse macrophages completely lacking Rho (RhoA, RhoB and RhoC) have severe lamellipodial retraction defects, but robust chemotactic navigation and increased motility

AU - Koenigs, Volker

AU - Jennings, Richard

AU - Vogl, Thomas

AU - Horsthemke, Markus

AU - Bachg, Anne C

AU - Xu, Yan

AU - Grobe, Kay

AU - Brakebusch, Cord Herbert

AU - Schwab, Albrecht

AU - Baehler, Martin

AU - Knaus, Ulla G

AU - Hanley, Peter J

N1 - Copyright © 2014, The American Society for Biochemistry and Molecular Biology.

PY - 2014/10/31

Y1 - 2014/10/31

N2 - RhoA is thought to be essential for coordination of the membrane protrusions and retractions required for immune cell motility and directed migration. Whether the subfamily of Rho (Ras homolog) GTPases (RhoA, RhoB and RhoC) is actually required for the directed migration of primary cells is difficult to predict. Macrophages isolated from myeloid-restricted RhoA/RhoB (conditional) double knockout (dKO) mice did not express RhoC and were essentially pan-Rho deficient. Using real-time chemotaxis assays, we found that retraction of the trailing edge was dissociated from advance of the cell body in dKO cells, which developed extremely elongated tails. Surprisingly, velocity (of the cell body) was increased, while chemotactic efficiency was preserved, compared to wild-type (WT) macrophages. Randomly migrating RhoA/RhoB dKO macrophages exhibited multiple small protrusions and developed large branches due to impaired lamellipodial retraction. A mouse model of peritonitis indicated that monocyte/macrophage recruitment was, surprisingly, more rapid in RhoA/RhoB dKO mice than in WT mice. In comparison to dKO cells, the phenotypes of single RhoA or RhoB deficient macrophages were mild due to mutual compensation. Furthermore, genetic deletion of RhoB partially reversed the motility defect of macrophages lacking the RhoGAP (Rho GTPase-activating protein) myosin IXb (Myo9b). In conclusion, the Rho subfamily is not required for front end functions (motility and chemotaxis), although both RhoA and RhoB are involved in pulling up the rear end and resorbing lamellipodial membrane protrusions. Macrophages lacking Rho proteins migrate faster in vitro, which, in the case of the peritoneum, translates to more rapid in vivo monocyte/macrophage recruitment.

AB - RhoA is thought to be essential for coordination of the membrane protrusions and retractions required for immune cell motility and directed migration. Whether the subfamily of Rho (Ras homolog) GTPases (RhoA, RhoB and RhoC) is actually required for the directed migration of primary cells is difficult to predict. Macrophages isolated from myeloid-restricted RhoA/RhoB (conditional) double knockout (dKO) mice did not express RhoC and were essentially pan-Rho deficient. Using real-time chemotaxis assays, we found that retraction of the trailing edge was dissociated from advance of the cell body in dKO cells, which developed extremely elongated tails. Surprisingly, velocity (of the cell body) was increased, while chemotactic efficiency was preserved, compared to wild-type (WT) macrophages. Randomly migrating RhoA/RhoB dKO macrophages exhibited multiple small protrusions and developed large branches due to impaired lamellipodial retraction. A mouse model of peritonitis indicated that monocyte/macrophage recruitment was, surprisingly, more rapid in RhoA/RhoB dKO mice than in WT mice. In comparison to dKO cells, the phenotypes of single RhoA or RhoB deficient macrophages were mild due to mutual compensation. Furthermore, genetic deletion of RhoB partially reversed the motility defect of macrophages lacking the RhoGAP (Rho GTPase-activating protein) myosin IXb (Myo9b). In conclusion, the Rho subfamily is not required for front end functions (motility and chemotaxis), although both RhoA and RhoB are involved in pulling up the rear end and resorbing lamellipodial membrane protrusions. Macrophages lacking Rho proteins migrate faster in vitro, which, in the case of the peritoneum, translates to more rapid in vivo monocyte/macrophage recruitment.

U2 - 10.1074/jbc.M114.563270

DO - 10.1074/jbc.M114.563270

M3 - Journal article

C2 - 25213860

VL - 289

SP - 30772

EP - 30784

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 44

ER -