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Matrix valency regulates integrin-mediated lymphoid adhesion via Syk kinase.

Stupack DG, Li E, Silletti SA, Kehler JA, Geahlen RL, Hahn K, Nemerow GR, Cheresh DA - J. Cell Biol. (1999)

Bottom Line: Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to attach to monomeric forms or fragments of these proteins without previous activation.Adhesion of nonactivated lymphoid cells to polymeric ECM components results in activation of the antigen receptor-associated Syk kinase that accumulates in adhesion-promoting podosomes.In fact, activation of Syk by antigen or agonists, as well as expression of an activated Syk mutant in lymphoid cells, facilitates their adhesion to monomeric ECM proteins or their fragments.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
Lymphocytes accumulate within the extracellular matrix (ECM) of tumor, wound, or inflammatory tissues. These tissues are largely comprised of polymerized adhesion proteins such as fibrin and fibronectin or their fragments. Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to attach to monomeric forms or fragments of these proteins without previous activation. This adhesion event depends on the appropriate spacing of integrin adhesion sites. Adhesion of nonactivated lymphoid cells to polymeric ECM components results in activation of the antigen receptor-associated Syk kinase that accumulates in adhesion-promoting podosomes. In fact, activation of Syk by antigen or agonists, as well as expression of an activated Syk mutant in lymphoid cells, facilitates their adhesion to monomeric ECM proteins or their fragments. These results reveal a cooperative interaction between signals emanating from integrins and antigen receptors that can serve to regulate stable lymphoid cell adhesion and retention within a remodeling ECM.

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Integrin αvβ3 mediates selective attachment to pentameric PB. (A) The lymphoblastoid cell lines (LCL) JY and JR,  as well as the lymphoid tumor cell lines RPMI 8226, RPMI 8866,  and Jurkat (all αvβ3+), and the cell lines DT40 and Ramos  (αvβ3−) were assessed for attachment to pentameric or monomeric PB by adhesion assay as previously described. (B) Human  peripheral blood mononuclear cells were sorted for positive expression of αvβ3 (FITC), and low expression of β1 (PE) (gated  box, inset) allowing for depletion of monocyte contamination  during purification of αvβ3-expressing lymphocyte populations.  Sorted lymphocytes were assessed for attachment to penton base  coated (10–20 nM) or fibrin/fibrinogen coated (100 nM) chamber  slides (105 cells/slide) and attached cells per field were quantified  by direct counting. Data are expressed as the mean specific attachment ± SE from six fields counted. A representative experiment from three experiments is shown.
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Figure 5: Integrin αvβ3 mediates selective attachment to pentameric PB. (A) The lymphoblastoid cell lines (LCL) JY and JR, as well as the lymphoid tumor cell lines RPMI 8226, RPMI 8866, and Jurkat (all αvβ3+), and the cell lines DT40 and Ramos (αvβ3−) were assessed for attachment to pentameric or monomeric PB by adhesion assay as previously described. (B) Human peripheral blood mononuclear cells were sorted for positive expression of αvβ3 (FITC), and low expression of β1 (PE) (gated box, inset) allowing for depletion of monocyte contamination during purification of αvβ3-expressing lymphocyte populations. Sorted lymphocytes were assessed for attachment to penton base coated (10–20 nM) or fibrin/fibrinogen coated (100 nM) chamber slides (105 cells/slide) and attached cells per field were quantified by direct counting. Data are expressed as the mean specific attachment ± SE from six fields counted. A representative experiment from three experiments is shown.

Mentions: Importantly, other LCL and nonadherent B and T lymphoid cells, such as RPMI 8866, RPMI 8226, and Jurkat, also attached selectively to multimeric αvβ3 ligands (Fig. 5 A). In each case, attachment could be inhibited with monoclonal antibody LM609 (data not shown). In contrast, B cell tumor lines which do not express αvβ3 such as DT40 and Ramos, failed to attach to either form of PB (Fig. 5 A). Although integrin αvβ3 has been described in tissue-associated lymphocyte populations (Halvorson et al., 1996), it is only minimally expressed on circulating lymphocytes (Hemler, 1990). However, when the subpopulation of lymphocytes expressing αvβ3 were isolated from peripheral blood (< 2%) (Fig. 5 B, inset), these cells also demonstrated selective adhesion to both multimeric PB and fibrin relative to monomeric PB and fibrinogen, respectively (Fig. 5 B). Thus, lymphocytes which express appropriate receptors can attach to multivalent ligands without a requirement for exogenous activation.


Matrix valency regulates integrin-mediated lymphoid adhesion via Syk kinase.

Stupack DG, Li E, Silletti SA, Kehler JA, Geahlen RL, Hahn K, Nemerow GR, Cheresh DA - J. Cell Biol. (1999)

Integrin αvβ3 mediates selective attachment to pentameric PB. (A) The lymphoblastoid cell lines (LCL) JY and JR,  as well as the lymphoid tumor cell lines RPMI 8226, RPMI 8866,  and Jurkat (all αvβ3+), and the cell lines DT40 and Ramos  (αvβ3−) were assessed for attachment to pentameric or monomeric PB by adhesion assay as previously described. (B) Human  peripheral blood mononuclear cells were sorted for positive expression of αvβ3 (FITC), and low expression of β1 (PE) (gated  box, inset) allowing for depletion of monocyte contamination  during purification of αvβ3-expressing lymphocyte populations.  Sorted lymphocytes were assessed for attachment to penton base  coated (10–20 nM) or fibrin/fibrinogen coated (100 nM) chamber  slides (105 cells/slide) and attached cells per field were quantified  by direct counting. Data are expressed as the mean specific attachment ± SE from six fields counted. A representative experiment from three experiments is shown.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2132930&req=5

Figure 5: Integrin αvβ3 mediates selective attachment to pentameric PB. (A) The lymphoblastoid cell lines (LCL) JY and JR, as well as the lymphoid tumor cell lines RPMI 8226, RPMI 8866, and Jurkat (all αvβ3+), and the cell lines DT40 and Ramos (αvβ3−) were assessed for attachment to pentameric or monomeric PB by adhesion assay as previously described. (B) Human peripheral blood mononuclear cells were sorted for positive expression of αvβ3 (FITC), and low expression of β1 (PE) (gated box, inset) allowing for depletion of monocyte contamination during purification of αvβ3-expressing lymphocyte populations. Sorted lymphocytes were assessed for attachment to penton base coated (10–20 nM) or fibrin/fibrinogen coated (100 nM) chamber slides (105 cells/slide) and attached cells per field were quantified by direct counting. Data are expressed as the mean specific attachment ± SE from six fields counted. A representative experiment from three experiments is shown.
Mentions: Importantly, other LCL and nonadherent B and T lymphoid cells, such as RPMI 8866, RPMI 8226, and Jurkat, also attached selectively to multimeric αvβ3 ligands (Fig. 5 A). In each case, attachment could be inhibited with monoclonal antibody LM609 (data not shown). In contrast, B cell tumor lines which do not express αvβ3 such as DT40 and Ramos, failed to attach to either form of PB (Fig. 5 A). Although integrin αvβ3 has been described in tissue-associated lymphocyte populations (Halvorson et al., 1996), it is only minimally expressed on circulating lymphocytes (Hemler, 1990). However, when the subpopulation of lymphocytes expressing αvβ3 were isolated from peripheral blood (< 2%) (Fig. 5 B, inset), these cells also demonstrated selective adhesion to both multimeric PB and fibrin relative to monomeric PB and fibrinogen, respectively (Fig. 5 B). Thus, lymphocytes which express appropriate receptors can attach to multivalent ligands without a requirement for exogenous activation.

Bottom Line: Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to attach to monomeric forms or fragments of these proteins without previous activation.Adhesion of nonactivated lymphoid cells to polymeric ECM components results in activation of the antigen receptor-associated Syk kinase that accumulates in adhesion-promoting podosomes.In fact, activation of Syk by antigen or agonists, as well as expression of an activated Syk mutant in lymphoid cells, facilitates their adhesion to monomeric ECM proteins or their fragments.

View Article: PubMed Central - PubMed

Affiliation: Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
Lymphocytes accumulate within the extracellular matrix (ECM) of tumor, wound, or inflammatory tissues. These tissues are largely comprised of polymerized adhesion proteins such as fibrin and fibronectin or their fragments. Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to attach to monomeric forms or fragments of these proteins without previous activation. This adhesion event depends on the appropriate spacing of integrin adhesion sites. Adhesion of nonactivated lymphoid cells to polymeric ECM components results in activation of the antigen receptor-associated Syk kinase that accumulates in adhesion-promoting podosomes. In fact, activation of Syk by antigen or agonists, as well as expression of an activated Syk mutant in lymphoid cells, facilitates their adhesion to monomeric ECM proteins or their fragments. These results reveal a cooperative interaction between signals emanating from integrins and antigen receptors that can serve to regulate stable lymphoid cell adhesion and retention within a remodeling ECM.

Show MeSH
Related in: MedlinePlus