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Mzali R, Seguin L, Liot C, Auger A, Pacaud P, Loirand G, Thibault C, Pierre J, Bertoglio J. Regulation of Rho signaling pathways in interleukin-2-stimulated human T-lymphocytes. FASEB J 2005; 19:1911-3. [PMID: 16148026 DOI: 10.1096/fj.05-4030fje] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rho GTPases are key regulators of many cellular functions, including cytoskeleton organization which is important for cell morphology and mobility, gene expression, cell cycle progression, and cytokinesis. In addition, it has recently been recognized that Rho GTPase activity is required for development of the immune system, as well as for the specialized functions of the peripheral cells that act in the immune response such as antigen presenting cells and lymphocytes. Stimulation of T lymphocytes with interleukin-2 (IL-2) induces clonal expansion of antigen-specific populations and provides a model to study cell cycle entry and cell cycle progression. We have performed gene expression analysis in a model of human T lymphocytes, which proliferate in response to IL-2. In addition to changes in genes relevant to cell cycling and to the antiapoptotic effects of IL-2, we have analyzed expression and variations of more than 300 genes involved in Rho GTPase signaling pathways. We report here that IL-2 regulates the expression of a number of proteins, which participate in the Rho GTPase pathways, including some of the GTPases themselves, GDP/GTP exchange factors, GTPase activating proteins, as well as GDIs and effectors. Our results suggest that regulation of expression of components of the Rho GTPase pathways may be an important mechanism in assembling specific signal transduction cascades that need to be active at certain times during the cell cycle. Some of our findings may also be relevant to the roles of Rho GTPases in T lymphocyte functions and proliferation.
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Affiliation(s)
- Rym Mzali
- Inserm U461, Faculté de Pharmacie Paris-XI, Chatenay-Malabry, France
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Vielkind S, Gallagher-Gambarelli M, Gomez M, Hinton HJ, Cantrell DA. Integrin regulation by RhoA in thymocytes. THE JOURNAL OF IMMUNOLOGY 2005; 175:350-7. [PMID: 15972668 DOI: 10.4049/jimmunol.175.1.350] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The guanine nucleotide-binding protein Rho has essential functions in T cell development and is important for the survival and proliferation of T cell progenitors in the thymus. To explore the mechanisms used by RhoA to control thymocyte biology, the role of this GTPase in the regulation of integrin-mediated cell adhesion was examined. The data show that RhoA activation is sufficient to stimulate beta(1) and beta(2) integrin-mediated adhesion in murine thymocytes. RhoA is also needed for integrin activation in vivo as loss of Rho function impaired the ability of thymocytes to adhere to the extracellular matrix protein VCAM-1 and prevented integrin activation induced by the GTPases Rac-1 and Rap1A in vivo. The regulated activity of integrins is needed for cell motility and in the present study it was seen that RhoA activity is critical for integrin-mediated thymocyte migration to chemokines in vitro. Thus, RhoA has a critical role in regulating cell adhesion and migration during T cell development.
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Affiliation(s)
- Susina Vielkind
- Lymphocyte Activation Laboratory, Cancer Research U.K. London Research Institute, Lincoln's Inn Fields Laboratories, London, United Kingdom
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McHardy LM, Warabi K, Andersen RJ, Roskelley CD, Roberge M. Strongylophorine-26, a Rho-dependent inhibitor of tumor cell invasion that reduces actin stress fibers and induces nonpolarized lamellipodial extensions. Mol Cancer Ther 2005; 4:772-8. [PMID: 15897241 DOI: 10.1158/1535-7163.mct-04-0310] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Strongylophorine-26, a new meroditerpenoid, was recently identified as an inhibitor of cancer cell invasion. This study was undertaken to characterize its mechanism of action. We find that strongylophorine-26 inhibits the motility of MDA-MB-231 breast carcinoma cells on a plastic surface. Upon addition of strongylophorine-26, rapid cell contraction and depolarization occurred, followed by spreading and flattening of the entire cell. Treated cells exhibited increased membrane ruffling throughout and extended lamellipodia in all directions. Strongylophorine-26 induced a decrease in actin stress fibers, a dramatic increase in the size and number of focal adhesions, and the appearance of a dense meshwork of actin filaments around the cell periphery. Strongylophorine-26 caused a transient activation of the small GTPase Rho and treatment with the Rho inhibitor C3 exoenzyme abrogated the anti-invasive activity of strongylophorine-26. These effects are distinct from those of many motility and angiogenesis inhibitors that seem to act by a common mechanism involving the induction of actin stress fibers. This difference in mechanism of action sets strongylophorine-26 apart as an experimental anticancer agent and indicates that pharmacologic inhibition of cell migration may be achieved by mechanisms not involving the stabilization of actin stress fibers.
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Affiliation(s)
- Lianne M McHardy
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2146 Health Sciences Mall, Vancouver, British Columbia, Canada V6T 1Z3, USA
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Nakayamada S, Kurose H, Saito K, Mogami A, Tanaka Y. Small GTP-binding protein Rho-mediated signaling promotes proliferation of rheumatoid synovial fibroblasts. Arthritis Res Ther 2005; 7:R476-84. [PMID: 15899034 PMCID: PMC1174939 DOI: 10.1186/ar1694] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 01/10/2005] [Accepted: 01/18/2005] [Indexed: 11/21/2022] Open
Abstract
Rho is a major small GTP-binding protein that is involved in the regulation of various cell functions, including proliferation and cell migration, through activation of multiple signaling molecules in various types of cells. We studied its roles in synovial fibroblasts (SFs) in patients with rheumatoid arthritis (RA) and clarified its relevance to RA synovitis, with the following results. 1)We found that the thrombin receptor was overexpressed on RA synovial fibroblasts (RA SFs) and that thrombin induced a marked proliferation and progression of the cell cycle to the S phase in these cells. 2)We also found that thrombin efficiently activated Rho. 3)Rho activation and proliferation and the progression of the cell cycle to the S phase were completely blocked by p115RGS (an N-terminal regulator of the G-protein signaling domain of p115RhoGEF) and by the C-terminal fragments of Gα13 (an inhibitor of the interaction of receptors with G13). 4)Thrombin induced the secretion of IL-6 by RA SFs, but this action was blocked by p115RGS or Gα13. Our findings show that the actions of thrombin on the proliferation of RA SFs, cell-cycle progression to the S phase, and IL-6 secretion were mainly mediated by the G13 and RhoGEF pathways. These results suggest that p115RGS and Gα13 could be potent inhibitors of such functions. A rational design of future therapeutic strategies for RA synovitis could perhaps include the exploitation of the Rho pathway to directly reduce the growth of synovial cells.
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Affiliation(s)
- Shingo Nakayamada
- First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Fukuoka, Japan
| | - Hitoshi Kurose
- Department of Pharmacology and Toxicology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kazuyoshi Saito
- First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Fukuoka, Japan
| | - Akira Mogami
- Pharmaceuticals Research Unit, Research & Development Division, Mitsubishi Pharma Corporation, Yokohama, Japan
| | - Yoshiya Tanaka
- First Department of Internal Medicine, University of Occupational and Environmental Health, School of Medicine, Fukuoka, Japan
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Vicente-Manzanares M, Cruz-Adalia A, Martín-Cófreces NB, Cabrero JR, Dosil M, Alvarado-Sánchez B, Bustelo XR, Sánchez-Madrid F. Control of lymphocyte shape and the chemotactic response by the GTP exchange factor Vav. Blood 2004; 105:3026-34. [PMID: 15618472 DOI: 10.1182/blood-2004-07-2925] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Rho GTPases control many facets of cell polarity and migration; namely, the reorganization of the cellular cytoskeleton to extracellular stimuli. Rho GTPases are activated by GTP exchange factors (GEFs), which induce guanosine diphosphate (GDP) release and the stabilization of the nucleotide-free state. Thus, the role of GEFs in the regulation of the cellular response to extracellular cues during cell migration is a critical step of this process. In this report, we have analyzed the activation and subcellular localization of the hematopoietic GEF Vav in human peripheral blood lymphocytes stimulated with the chemokine stromal cell-derived factor-1 (SDF-1alpha). We show a robust activation of Vav and its redistribution to motility-associated subcellular structures, and we provide biochemical evidence of the recruitment of Vav to the membrane of SDF-1alpha-activated human lymphocytes, where it transiently interacts with the SDF-1alpha receptor CXCR4. Overexpression of a dominant negative form of Vav abolished lymphocyte polarization, actin polymerization, and migration. SDF-1alpha-mediated cell polarization and migration also were impaired by overexpression of an active, oncogenic Vav, although the mechanism appears to be different. Together, our data postulate a pivotal role for Vav in the transmission of the migratory signal through the chemokine receptor CXCR4.
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Pomorski P, Watson JM, Haskill S, Jacobson KA. How adhesion, migration, and cytoplasmic calcium transients influence interleukin-1beta mRNA stabilization in human monocytes. ACTA ACUST UNITED AC 2004; 57:143-57. [PMID: 14743348 DOI: 10.1002/cm.10159] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
We investigated the mechanisms by which primary human monocyte migration and the production of important cytokines are co-regulated. Motile monocytes underwent cyclic morphologic and adhesive changes that were associated with intracellular free calcium changes; in such cells, cytokine transcripts were unstable and translationally repressed. Agents that activate monocytes, including lipopolysacharrides (LPS), cytomegalovirus (CMV), and tumor necrosis factor (TNFalpha), have been shown to de-repress translation and these agents stabilize adhesion-induced transcripts for IL-lbeta and IL-8 and markedly diminish cell migration in the presence of autologous serum. LPS suppressed Rho A activity and either this agent or C3 transferase elevated intracellular free calcium, stabilized transcripts, and, in tandem, inhibited cell migration by preventing tail retraction, a prerequisite for cell translocation. These results, therefore, suggest that monocyte activating agents inhibit the RhoA pathway and continuously elevate intracellular calcium leading to a concomitant decrease in monocyte migration and stabilization of cytokine transcripts prior to translation.
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Affiliation(s)
- P Pomorski
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, 27599, USA
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Rundle DR, Gorbsky G, Tsiokas L. PKD2 Interacts and Co-localizes with mDia1 to Mitotic Spindles of Dividing Cells. J Biol Chem 2004; 279:29728-39. [PMID: 15123714 DOI: 10.1074/jbc.m400544200] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mutations in pkd2 result in the type 2 form of autosomal dominant polycystic kidney disease, which accounts for approximately 15% of all cases of the disease. PKD2, the protein product of pkd2, belongs to the transient receptor potential superfamily of cation channels, and it can function as a mechanosensitive channel in the primary cilium of kidney cells, an intracellular Ca(2+) release channel in the endoplasmic reticulum, and/or a nonselective cation channel in the plasma membrane. We have identified mDia1/Drf1 (mammalian Diaphanous or Diaphanous-related formin 1 protein) as a PKD2-interacting protein by yeast two-hybrid screen. mDia1 is a member of the RhoA GTPase-binding formin homology protein family that participates in cytoskeletal organization, cytokinesis, and signal transduction. We show that mDia1 and PKD2 interact in native and in transfected cells, and binding is mediated by the cytoplasmic C terminus of PKD2 binding to the mDia1 N terminus. The interaction is more prevalent in dividing cells in which endogenous PKD2 and mDia1 co-localize to the mitotic spindles. RNA interference experiments reveal that endogenous mDia1 knockdown in HeLa cells results in the loss of PKD2 from mitotic spindles and alters intracellular Ca(2+) release. Our results suggest that mDia1 facilitates the movement of PKD2 to a centralized position during cell division and has a positive effect on intracellular Ca(2+) release during mitosis. This may be important to ensure equal segregation of PKD2 to the daughter cell to maintain a necessary level of channel activity. Alternatively, PKD2 channel activity may be important in the cell division process or in cell fate decisions after division.
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Affiliation(s)
- Dana R Rundle
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA
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Vicente-Manzanares M, Sánchez-Madrid F. Role of the cytoskeleton during leukocyte responses. Nat Rev Immunol 2004; 4:110-22. [PMID: 15040584 DOI: 10.1038/nri1268] [Citation(s) in RCA: 272] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The cytoskeleton is a cellular network of structural, adaptor and signalling molecules that regulates most cellular functions that are related to the immune response, including migration, extravasation, antien recognition, activation and phagocytosis by different subsets of leukocytes. Recently, a large number of regulatory elements and structural constituents of the leukocyte cytoskeleton have been identified. In this review, we discuss the composition and regulation of the different cytoskeletal elements and their role in immune responses.
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Affiliation(s)
- Miguel Vicente-Manzanares
- Servicio de Inmunología, Hospital Universitario de la Princesa, c/Diego de León 62, 28006-Madrid, Spain
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