{"id":{"repo_id":"aachen","oai_identifier":"oai:publications.rwth-aachen.de:62440"},"canonical_url":"https://search.dev.ndltd.org/etd/aachen/oai:publications.rwth-aachen.de:62440","repository":{"repo_id":"aachen","name":"RWTH Aachen University","base_url":"https://publications.rwth-aachen.de/oai2d"},"display":{"title":"Involvement of the LFA-1 ligand JAM-A in inflammatory recruitment of mononuclear cells : identification of the JAM-A binding domain in LFA-1","abstract":"Junctional adhesion molecule-A (JAM-A) is a ligand of the integrin lymphocyte function-associated antigen-1 (LFA-1). In this study the JAM-A binding site in LFA-1 was identified and the involvement of JAM-A in inflammatory recruitment of mononuclear cells was analyzed. Furthermore, a functional contribution of JAM-A to atherogenesis was investigated. By deletion of the I domain in the aL subunit of LFA-1 and expression of this aL mutant in aL-deficient Jurkat J-ß2.7 T cells, it was here demonstrated that the I domain of LFA-1 is crucial for adhesion to immobilized JAM-A. This was substantiated by blocking the stimulated adhesion of T cells or monocytes to JAM-A using the I domain-directed mAb TS1/22 or the small molecule antagonist BIRT377, which stabilizes the low-affinity conformation of the I domain. The immobilized LFA-1 I domain locked in the open high-affinity conformation was sufficient to support adhesion of transfected Chinese hamster ovary cells expressing human JAM-A. A solid-phase binding assay confirmed a direct interaction of recombinant JAM-A with immobilized LFA 1 I domain locked in the open high-affinity conformation. These data have demonstrated that the I domain of LFA-1 is sufficient and required for the functional interactions of LFA-1 with JAM-A. Using soluble JAM-A.Fc chimeric protein as a competitive inhibitor, the involvement of JAM-A in distinct steps of mononuclear cells recruitment was analyzed. Adhesion assays revealed that LFA-1-mediated binding of T cells or monocytes to immobilized ICAM-1 or cytokine-costimulated endothelium was dose-dependently inhibited by soluble JAM-A.Fc. Similarly, soluble JAM-A.Fc reduced the LFA-1-mediated SDF-1-triggered arrest under flow conditions and transendothelial chemotaxis of T cells. These data have shown that soluble JAM-A can be effectively applied to inhibit distinct steps of inflammatory recruitment of mononuclear cells. Immunofluorescence and real-time RT-PCR analysis showed an upregulation of JAM-A expression on early atherosclerotic endothelium of carotid arteries from apolipoprotein E-deficient (apoE-/-) mice fed a high fat Western-type diet. In ex vivo perfusion assays, soluble JAM-A.Fc inhibited the VLA-4-independent accumulation of mononuclear cells on atherosclerotic endothelium. Together with the upregulation of JAM-A on atherosclerotic endothelium, this suggests a functional contribution of JAM-A to atherogenesis. The role of endothelial JAM-A in atherogenic recruitment was further substantiated by an attenuation of monocyte arrest and transmigration on activated JAM-A-/-apoE-/- versus JAM-A+/+apoE-/- mouse aortal endothelial cells in vitro. The findings from this work may be helpful in designing new stategies for the development of anti-inflammatory therapies.","abstract_html":"Junctional adhesion molecule-A (JAM-A) is a ligand of the integrin lymphocyte function-associated antigen-1 (LFA-1). In this study the JAM-A binding site in LFA-1 was identified and the involvement of JAM-A in inflammatory recruitment of mononuclear cells was analyzed. Furthermore, a functional contribution of JAM-A to atherogenesis was investigated. By deletion of the I domain in the aL subunit of LFA-1 and expression of this aL mutant in aL-deficient Jurkat J-ß2.7 T cells, it was here demonstrated that the I domain of LFA-1 is crucial for adhesion to immobilized JAM-A. This was substantiated by blocking the stimulated adhesion of T cells or monocytes to JAM-A using the I domain-directed mAb TS1/22 or the small molecule antagonist BIRT377, which stabilizes the low-affinity conformation of the I domain. The immobilized LFA-1 I domain locked in the open high-affinity conformation was sufficient to support adhesion of transfected Chinese hamster ovary cells expressing human JAM-A. A solid-phase binding assay confirmed a direct interaction of recombinant JAM-A with immobilized LFA 1 I domain locked in the open high-affinity conformation. These data have demonstrated that the I domain of LFA-1 is sufficient and required for the functional interactions of LFA-1 with JAM-A. Using soluble JAM-A.Fc chimeric protein as a competitive inhibitor, the involvement of JAM-A in distinct steps of mononuclear cells recruitment was analyzed. Adhesion assays revealed that LFA-1-mediated binding of T cells or monocytes to immobilized ICAM-1 or cytokine-costimulated endothelium was dose-dependently inhibited by soluble JAM-A.Fc. Similarly, soluble JAM-A.Fc reduced the LFA-1-mediated SDF-1-triggered arrest under flow conditions and transendothelial chemotaxis of T cells. These data have shown that soluble JAM-A can be effectively applied to inhibit distinct steps of inflammatory recruitment of mononuclear cells. Immunofluorescence and real-time RT-PCR analysis showed an upregulation of JAM-A expression on early atherosclerotic endothelium of carotid arteries from apolipoprotein E-deficient (apoE-/-) mice fed a high fat Western-type diet. In ex vivo perfusion assays, soluble JAM-A.Fc inhibited the VLA-4-independent accumulation of mononuclear cells on atherosclerotic endothelium. Together with the upregulation of JAM-A on atherosclerotic endothelium, this suggests a functional contribution of JAM-A to atherogenesis. The role of endothelial JAM-A in atherogenic recruitment was further substantiated by an attenuation of monocyte arrest and transmigration on activated JAM-A-/-apoE-/- versus JAM-A+/+apoE-/- mouse aortal endothelial cells in vitro. The findings from this work may be helpful in designing new stategies for the development of anti-inflammatory therapies.","abstract_has_math":false,"creators":["Fraemohs, Line Rebo"],"institution":"Publikationsserver der RWTH Aachen University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Fischer, Rainer"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007","date_published":"2007","updated_at":"2026-07-30T19:43:28Z","subjects":["info:eu-repo/classification/ddc/570","Zell-Adhäsionsmolekül","Tight junction","Chemotaxis","Atherogenese","Biowissenschaften, Biologie","cell adhesion molecule","atherogenesis"],"languages":["eng"],"rights":["info:eu-repo/semantics/openAccess"],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124009%22"],"render_values":[{"text":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124009%22","href":"https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124009%22","code":true}]}]},"links":{"outbound_url":"https://publications.rwth-aachen.de/record/62440","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Fischer, Rainer"]},{"key":"dc:creator","label":"Author","values":["Fraemohs, Line Rebo"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:coverage","label":"Dc Coverage","values":["DE"]},{"key":"dc:date","label":"Dc Date","values":["2007"]},{"key":"dc:publisher","label":"Institution","values":["Publikationsserver der RWTH Aachen University"]},{"key":"dc:relation","label":"Dc Relation","values":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-19965"]},{"key":"dc:type","label":"Dc Type","values":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["info:eu-repo/classification/ddc/570","Zell-Adhäsionsmolekül","Tight junction","Chemotaxis","Atherogenese","Biowissenschaften, Biologie","cell adhesion molecule","atherogenesis"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["eng"]},{"key":"dc:rights","label":"Dc Rights","values":["info:eu-repo/semantics/openAccess"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://publications.rwth-aachen.de/record/62440","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124009%22"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Junctional adhesion molecule-A (JAM-A) is a ligand of the integrin lymphocyte function-associated antigen-1 (LFA-1). In this study the JAM-A binding site in LFA-1 was identified and the involvement of JAM-A in inflammatory recruitment of mononuclear cells was analyzed. Furthermore, a functional contribution of JAM-A to atherogenesis was investigated. By deletion of the I domain in the aL subunit of LFA-1 and expression of this aL mutant in aL-deficient Jurkat J-ß2.7 T cells, it was here demonstrated that the I domain of LFA-1 is crucial for adhesion to immobilized JAM-A. This was substantiated by blocking the stimulated adhesion of T cells or monocytes to JAM-A using the I domain-directed mAb TS1/22 or the small molecule antagonist BIRT377, which stabilizes the low-affinity conformation of the I domain. The immobilized LFA-1 I domain locked in the open high-affinity conformation was sufficient to support adhesion of transfected Chinese hamster ovary cells expressing human JAM-A. A solid-phase binding assay confirmed a direct interaction of recombinant JAM-A with immobilized LFA 1 I domain locked in the open high-affinity conformation. These data have demonstrated that the I domain of LFA-1 is sufficient and required for the functional interactions of LFA-1 with JAM-A. Using soluble JAM-A.Fc chimeric protein as a competitive inhibitor, the involvement of JAM-A in distinct steps of mononuclear cells recruitment was analyzed. Adhesion assays revealed that LFA-1-mediated binding of T cells or monocytes to immobilized ICAM-1 or cytokine-costimulated endothelium was dose-dependently inhibited by soluble JAM-A.Fc. Similarly, soluble JAM-A.Fc reduced the LFA-1-mediated SDF-1-triggered arrest under flow conditions and transendothelial chemotaxis of T cells. These data have shown that soluble JAM-A can be effectively applied to inhibit distinct steps of inflammatory recruitment of mononuclear cells. Immunofluorescence and real-time RT-PCR analysis showed an upregulation of JAM-A expression on early atherosclerotic endothelium of carotid arteries from apolipoprotein E-deficient (apoE-/-) mice fed a high fat Western-type diet. In ex vivo perfusion assays, soluble JAM-A.Fc inhibited the VLA-4-independent accumulation of mononuclear cells on atherosclerotic endothelium. Together with the upregulation of JAM-A on atherosclerotic endothelium, this suggests a functional contribution of JAM-A to atherogenesis. The role of endothelial JAM-A in atherogenic recruitment was further substantiated by an attenuation of monocyte arrest and transmigration on activated JAM-A-/-apoE-/- versus JAM-A+/+apoE-/- mouse aortal endothelial cells in vitro. The findings from this work may be helpful in designing new stategies for the development of anti-inflammatory therapies."]},{"key":"dc:source","label":"Dc Source","values":["Aachen : Publikationsserver der RWTH Aachen University V, 95 S. : graph. Darst. (2007). = Aachen, Techn. Hochsch., Diss., 2007"]},{"key":"dc:title","label":"Title","values":["Involvement of the LFA-1 ligand JAM-A in inflammatory recruitment of mononuclear cells : identification of the JAM-A binding domain in LFA-1"]}]}],"canonical_facts":{"dc:contributor":["Fischer, Rainer"],"dc:coverage":["DE"],"dc:creator":["Fraemohs, Line Rebo"],"dc:date":["2007"],"dc:description":["Junctional adhesion molecule-A (JAM-A) is a ligand of the integrin lymphocyte function-associated antigen-1 (LFA-1). In this study the JAM-A binding site in LFA-1 was identified and the involvement of JAM-A in inflammatory recruitment of mononuclear cells was analyzed. Furthermore, a functional contribution of JAM-A to atherogenesis was investigated. By deletion of the I domain in the aL subunit of LFA-1 and expression of this aL mutant in aL-deficient Jurkat J-ß2.7 T cells, it was here demonstrated that the I domain of LFA-1 is crucial for adhesion to immobilized JAM-A. This was substantiated by blocking the stimulated adhesion of T cells or monocytes to JAM-A using the I domain-directed mAb TS1/22 or the small molecule antagonist BIRT377, which stabilizes the low-affinity conformation of the I domain. The immobilized LFA-1 I domain locked in the open high-affinity conformation was sufficient to support adhesion of transfected Chinese hamster ovary cells expressing human JAM-A. A solid-phase binding assay confirmed a direct interaction of recombinant JAM-A with immobilized LFA 1 I domain locked in the open high-affinity conformation. These data have demonstrated that the I domain of LFA-1 is sufficient and required for the functional interactions of LFA-1 with JAM-A. Using soluble JAM-A.Fc chimeric protein as a competitive inhibitor, the involvement of JAM-A in distinct steps of mononuclear cells recruitment was analyzed. Adhesion assays revealed that LFA-1-mediated binding of T cells or monocytes to immobilized ICAM-1 or cytokine-costimulated endothelium was dose-dependently inhibited by soluble JAM-A.Fc. Similarly, soluble JAM-A.Fc reduced the LFA-1-mediated SDF-1-triggered arrest under flow conditions and transendothelial chemotaxis of T cells. These data have shown that soluble JAM-A can be effectively applied to inhibit distinct steps of inflammatory recruitment of mononuclear cells. Immunofluorescence and real-time RT-PCR analysis showed an upregulation of JAM-A expression on early atherosclerotic endothelium of carotid arteries from apolipoprotein E-deficient (apoE-/-) mice fed a high fat Western-type diet. In ex vivo perfusion assays, soluble JAM-A.Fc inhibited the VLA-4-independent accumulation of mononuclear cells on atherosclerotic endothelium. Together with the upregulation of JAM-A on atherosclerotic endothelium, this suggests a functional contribution of JAM-A to atherogenesis. The role of endothelial JAM-A in atherogenic recruitment was further substantiated by an attenuation of monocyte arrest and transmigration on activated JAM-A-/-apoE-/- versus JAM-A+/+apoE-/- mouse aortal endothelial cells in vitro. The findings from this work may be helpful in designing new stategies for the development of anti-inflammatory therapies."],"dc:identifier":["https://publications.rwth-aachen.de/record/62440","https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-124009%22"],"dc:language":["eng"],"dc:publisher":["Publikationsserver der RWTH Aachen University"],"dc:relation":["info:eu-repo/semantics/altIdentifier/urn/urn:nbn:de:hbz:82-opus-19965"],"dc:rights":["info:eu-repo/semantics/openAccess"],"dc:source":["Aachen : Publikationsserver der RWTH Aachen University V, 95 S. : graph. Darst. (2007). = Aachen, Techn. Hochsch., Diss., 2007"],"dc:subject":["info:eu-repo/classification/ddc/570","Zell-Adhäsionsmolekül","Tight junction","Chemotaxis","Atherogenese","Biowissenschaften, Biologie","cell adhesion molecule","atherogenesis"],"dc:title":["Involvement of the LFA-1 ligand JAM-A in inflammatory recruitment of mononuclear cells : identification of the JAM-A binding domain in LFA-1"],"dc:type":["info:eu-repo/semantics/doctoralThesis","info:eu-repo/semantics/publishedVersion"]},"updated_at":"2026-07-30T19:43:28Z"}