Lymphocyte arrest requires instantaneous induction of an extended LFA-1 conformation mediated by endothelium-bound chemokines

Shamri, Revital; Grabovsky, Valentin; Gauguet, Jean-Marc; Feigelson, Sara W.; Manevich, Eugenia; Kolanus, Waldemar; Robinson, Martyn K.; Staunton, Donald E.; Andrian, Ulrich H. von; Alon, Ronen

doi:10.1038/ni1194

Cited by 355 publications

(441 citation statements)

References 48 publications

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“…6,7 In circulating leukocytes, LFA-1 remains largely inactive but becomes activated by endothelium-presented chemokines by signaling through G-protein-coupled receptors and application of shear stress, resulting in the extension of the molecule followed by immediate ligand binding. 8 The role of integrin activation in transendothelial migration has been widely studied. 9 Homing of DCs through the afferent lymphatics to the lymph nodes is still not completely understood and was assumed to passively follow the intrinsic flow of the lymph.…”

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confidence: 99%

The lymphoid chemokine CCL21 triggers LFA‐1 adhesive properties on human dendritic cells

et al. 2010

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Dendritic cells (DCs) are the most potent APCs, involved in the induction of immunity and tolerance. Recently we showed that during differentiation of human DCs from monocyte precursors, Lymphocyte function-associated antigen-1 (LFA-1)-binding capacity is lost, although integrin expression levels were maintained constant, suggesting a different regulation mechanism of this integrin on different cell types. However, the exact role of LFA-1 in DC adhesion and migration remains obscure. Chemokines are potent regulators of integrin function, influencing migratory and adhesive properties of leukocytes. Here, we show that upon vaccination of cancer patients with human DCs, cells that have migrated in vivo into the lymph nodes upregulated the active form of LFA-1. We further show that exposure of human DCs to the lymphoid chemokine CCL21 specifically restores the high-affinity form of LFA-1 and induces binding to its ligand ICAM-1 under low shear stress. Our data indicate that on DCs LFA-1 may function as an inducible anchor during lymphatic transmigration or within the lymph nodes. A thorough understanding of the adhesive events during the DC life cycle will help to improve the outcome of DC-based antitumor clinical trials. Keywords: integrin; cell adhesion; affinity; migration; antigen-presenting cell Dendritic cells (DCs) are the most potent antigen-presenting cells (APCs), involved in the induction of immunity and tolerance. 1 DCs presenting foreign or self-antigen migrate to the lymph node, a spatially defined compartment that facilitates encounter of APCs with rare Ag-specific naive T and B cells. DCs originate from precursor cells in the blood (for example, monocytes) and are recruited to the tissues by transendothelial migration mediated by integrin-dependent arrest. 2 Several clinical studies exploit monocyte-derived DC (moDCs) vaccines to induce antigen-specific response in cancer patients. 3 Integrins are transmembrane a/b-heterodimers that regulate cell-cell and cell-extracellular matrix interactions. Lymphocyte function-associated antigen-1 (LFA-1, aLb2) is a leukocyte-specific integrin that mediates firm arrest on the endothelium and, within tissues, cell tethering and the formation of the immunological synapse. 4 LFA-1 shifts between bent, low-affinity and variable extended conformations with high affinity to its ligand intercellular adhesion molecule-1 (ICAM-1) and to a lesser extent also to ICAM-2 and ICAM-3. 5 Ligand binding can further be increased by dynamic redistribution of LFA-1 in the cell membrane, a phenomenon designated as avidity regulation. 6,7 In circulating leukocytes, LFA-1 remains largely inactive but becomes activated by endothelium-presented chemokines by signaling through G-protein-coupled receptors and application of shear stress, resulting in the extension of the molecule followed by immediate ligand binding. 8 The role of integrin activation in transendothelial migration has been widely studied. 9 Homing of DCs through the afferent lymphatics to the lymph nodes is still not comple...

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confidence: 99%

The lymphoid chemokine CCL21 triggers LFA‐1 adhesive properties on human dendritic cells

et al. 2010

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“…In situ activation of the ␣␤ integrin heterodimer is rapidly triggered by the binding of specialized endothelial chemokines to G protein-coupled receptors (GPCRs) 3 (5)(6)(7)(8)(9). In vitro studies suggest that lymphocyte GPCRs such as CXCR4, CCR7 and CXCR3, when occupied by surface-presented rather than soluble ligands, can transmit a series of cytoplasmic signals that result in LFA-1 activation (8,10). This signaling occurs within subseconds through Gi heterotrimeric G protein activation.…”

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confidence: 99%

“…This signaling occurs within subseconds through Gi heterotrimeric G protein activation. A critical step in integrin activation is the almost instantaneous stabilization of an extended conformational state that must be rapidly coupled to the ligand-induced activation of the integrin headpiece (10,11).…”

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confidence: 99%

“…Nevertheless, the contribution of each RhoA modality to the very initial LFA-1-mediated arrest step on ICAM-1 and the mechanism by which specific RhoA regions regulate LFA-1 affinity, i.e., by instantaneous stabilization of an extended conformational state taking place under shear stress conditions and/or by ligand-induced integrin activation have not been elucidated. An alternative effector system that regulates LFA-1 valency (avidity) and adhesiveness to ICAM-1 are diacylglycerol (DAG)-dependent protein kinase Cs (PKCs) (10,(15)(16)(17). Although neither classical (DAG and Ca 2ϩ dependent) nor novel (DAG dependent-but Ca 2ϩ -independent) PKC isozymes play a role in rapid chemokine-triggered LFA-1 activation (10,13,14), recent studies implicated classical PKCs in LFA-1 activation by selectin ligands on subsets of T cells, leading to their arrest on ICAM-1 (17).…”

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confidence: 99%

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RhoA Is Involved in LFA-1 Extension Triggered by CXCL12 but Not in a Novel Outside-In LFA-1 Activation Facilitated by CXCL9

Pasvolsky

Grabovsky

Giagulli

et al. 2008

The Journal of Immunology

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Chemokines presented on endothelial tissues instantaneously trigger LFA-1-mediated arrest on ICAM-1 via rapid inside-out and outside-in (ligand-driven) LFA-1 activation. The GTPase RhoA was previously implicated in CCL21-triggered LFA-1 affinity triggering in murine T lymphocytes and in LFA-1-dependent adhesion strengthening to ICAM-1 on Peyer’s patch high endothelial venules stabilized over periods of at least 10 s. In this study, we show that a specific RhoA 23/40 effector region is vital for the initial LFA-1-dependent adhesions of lymphocytes on high endothelial venules lasting 1–3 s. Blocking the RhoA 23/40 region in human T lymphocytes in vitro also impaired the subsecond CXCL12-triggered LFA-1-mediated T cell arrest on ICAM-1 by eliminating the rapid induction of an extended LFA-1 conformational state. However, the inflammatory chemokine CXCL9 triggered robust LFA-1-mediated T lymphocyte adhesion to ICAM-1 at subsecond contacts independently of the RhoA 23/40 region. CXCL9 did not induce conformational changes in the LFA-1 ectodomain, suggesting that particular chemokines can activate LFA-1 through outside-in post ligand binding stabilization changes. Like CXCL9, the potent diacylglycerol-dependent protein kinase C agonist PMA was found to trigger LFA-1 adhesiveness to ICAM-1 also without inducing integrin extension or an a priori clustering and independently of the RhoA 23/40 region. Our results collectively suggest that the 23/40 region of RhoA regulates chemokine-induced inside-out LFA-1 extension before ligand binding, but is not required for a variety of chemokine and non-chemokine signals that rapidly strengthen LFA-1-ICAM-1 bonds without an a priori induction of high-affinity extended LFA-1 conformations.

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“…CD11a (integrin alpha L, or Itgal ) heterodimerizes with the β2‐integrin CD18 to form LFA1. LFA1 interacts with ICAM‐1 and has roles in transendothelial migration, activation, and differentiation of lymphocytes 15, 16, 17, 18. We found that while CD11a is expressed on nearly all hematopoietic lineages, it is downregulated on HSCs 19.…”

Section: Introductionmentioning

confidence: 74%

The CD11a and Endothelial Protein C Receptor Marker Combination Simplifies and Improves the Purification of Mouse Hematopoietic Stem Cells

Karimzadeh

Scarfone

Varady

et al. 2018

Stem Cells Translational Medicine

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Hematopoietic stem cells (HSCs) are the self‐renewing multipotent progenitors to all blood cell types. Identification and isolation of HSCs for study has depended on the expression of combinations of surface markers on HSCs that reliably distinguish them from other cell types. However, the increasing number of markers required to isolate HSCs has made it tedious, expensive, and difficult for newcomers, suggesting the need for a simpler panel of HSC markers. We previously showed that phenotypic HSCs could be separated based on expression of CD11a and that only the CD11a negative fraction contained true HSCs. Here, we show that CD11a and another HSC marker, endothelial protein C receptor (EPCR), can be used to effectively identify and purify HSCs. We introduce a new two‐color HSC sorting method that can highly enrich for HSCs with efficiencies comparable to the gold standard combination of CD150 and CD48. Our results demonstrate that adding CD11a and EPCR to the HSC biologist's toolkit improves the purity of and simplifies isolation of HSCs. stem cells translational medicine 2018;7:468–476

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Lymphocyte arrest requires instantaneous induction of an extended LFA-1 conformation mediated by endothelium-bound chemokines

Cited by 355 publications

References 48 publications

The lymphoid chemokine CCL21 triggers LFA‐1 adhesive properties on human dendritic cells

The lymphoid chemokine CCL21 triggers LFA‐1 adhesive properties on human dendritic cells

RhoA Is Involved in LFA-1 Extension Triggered by CXCL12 but Not in a Novel Outside-In LFA-1 Activation Facilitated by CXCL9

The CD11a and Endothelial Protein C Receptor Marker Combination Simplifies and Improves the Purification of Mouse Hematopoietic Stem Cells

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