title: Involvement of adenosine A3 receptors in the chemotactic navigation of macrophages towards apoptotic cells.
abstract: The first step in the clearance of apoptotic cells is chemotactic migration of macrophages towards the apoptotic cells guided by find-me signals provided by the dying cells. Upon sensing the chemotactic signals, macrophages release ATP. ATP is then degraded to ADP, AMP and adenosine to trigger purinergic receptors concentrated at the leading edge of the cell. Previous studies have shown that in addition to the chemotactic signals, this purinergic autocrine signaling is required to amplify and translate chemotactic signals into directional motility. In the present study the involvement of adenosine A3receptors (A3R) was studied in the chemotactic migration of macrophages directed by apoptotic thymocyte-derived find-me signals. By taking video images in vitro, we demonstrate 1, by administering apyrase, which degrades ATP and ADP, that the purinergic autocrine signaling is required for maintaining both the velocity and the directionality of macrophage migration towards the apoptotic thymocytes; 2, by readding 5'-N-ethylcarboxamidoadenosine, an adenosine analogue, to apyrase treated cells that the adenosine receptor signaling alone is sufficient to act so; and 3, by studying migration of various adenosine receptor null or adenosine receptor antagonist-treated macrophages, that the individual loss of the A3R signaling leads to the loss of chemotactic navigation. Though loss of A3Rs does not affect the phagocytotic capacity of macrophages, intraperitoneally-injected apoptotic thymocytes were cleared with a delayed kinetics by A3R null macrophages in vivo due to the impaired chemotactic navigation. All together these data demonstrate the involvement of macrophage A3Rs in the proper chemotactic navigation and consequent in vivo clearance of apoptotic cells. Interestingly, loss of A3Rs did not affect the in vivo clearance of apoptotic thymocytes in the dexamethasone-treated thymus.
authors.affiliation: Dental Biochemistry Section, Department of Biochemistry and Molecular Biology, Faculty of Dentistry, Research Center of Molecular Medicine, Hungary.
authors.forename: Gergely
authors.initials: G
authors.lastname: Joós
authors.affiliation: Department of Biotechnology and Microbiology, Faculty of Science and Technology, Hungary.
authors.forename: Judit
authors.initials: J
authors.lastname: Jákim
authors.affiliation: Dental Biochemistry Section, Department of Biochemistry and Molecular Biology, Faculty of Dentistry, Research Center of Molecular Medicine, Hungary.
authors.forename: Beáta
authors.initials: B
authors.lastname: Kiss
authors.affiliation: Department of Biotechnology and Microbiology, Faculty of Science and Technology, Hungary.
authors.forename: Regina
authors.initials: R
authors.lastname: Szamosi
authors.affiliation: Division of Oral Anatomy, Department of Anatomy, Histology and Embryology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, Hungary.
authors.forename: Tamás
authors.initials: T
authors.lastname: Papp
authors.affiliation: Division of Oral Anatomy, Department of Anatomy, Histology and Embryology, Faculty of Dentistry, University of Debrecen, H-4012 Debrecen, Hungary.
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Felszeghy
authors.affiliation: Dental Biochemistry Section, Department of Biochemistry and Molecular Biology, Faculty of Dentistry, Research Center of Molecular Medicine, Hungary.
authors.forename: Tibor
authors.initials: T
authors.lastname: Sághy
authors.affiliation: Department of Biotechnology and Microbiology, Faculty of Science and Technology, Hungary.
authors.forename: Gábor
authors.initials: G
authors.lastname: Nagy
authors.affiliation: Dental Biochemistry Section, Department of Biochemistry and Molecular Biology, Faculty of Dentistry, Research Center of Molecular Medicine, Hungary. Electronic address: szondy@med.unideb.hu.
authors.forename: Zsuzsa
authors.initials: Z
authors.lastname: Szondy
mesh_terms: D000241:Adenosine / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000235:genetics* / Q000276:immunology*; D001081:Apyrase; D019898:Autocrine Communication; D002634:Chemotaxis, Leukocyte / Q000235:genetics* / Q000276:immunology*; D003907:Dexamethasone / Q000494:pharmacology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D010587:Phagocytosis; D043705:Receptor, Adenosine A2A / Q000235:genetics / Q000378:metabolism; D043684:Receptor, Adenosine A3 / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D060168:Thymocytes / Q000276:immunology / Q000378:metabolism; D013950:Thymus Gland / Q000187:drug effects / Q000276:immunology / Q000378:metabolism
chemical_list: D043705:Receptor, Adenosine A2A; D043684:Receptor, Adenosine A3; D003907:Dexamethasone; D001081:Apyrase; D000241:Adenosine
keywords: Adenosine; Adenosine A3 receptor; Apoptotic thymocyte; Chemotactic migration; Macrophage