Abstract
The chemokine CXCL12/stromal cell-derived factor-1 is important for leukocyte migration to lymphoid organs and inflamed tissues and stimulates tumor development. In vitro, CXCL12 activity through CXCR4 is abolished by proteolytic processing. However, limited information is available on in vivo effects of posttranslationally modified CXCL12. Natural CXCL12 was purified from the coculture supernatant of stromal cells stimulated with leukocytes and inflammatory agents. In this conditioned medium, CXCL12 with a nitration on Tyr7, designated [3-NT7]CXCL12, was discovered via Edman degradation. CXCL12 and [3-NT7]CXCL12 were chemically synthesized to evaluate the biological effects of this modification. [3-NT7]CXCL12 recruited β-arrestin 2 and phosphorylated the Akt kinase similar to CXCL12 in receptor-transfected cells. Also the affinity of CXCL12 and [3-NT7]CXCL12 for glycosaminoglycans, the G protein-coupled chemokine receptor CXCR4 and the atypical chemokine receptor ACKR3 were comparable. However, [3-NT7]CXCL12 showed a reduced ability to enhance intracellular calcium concentrations, to generate inositol triphosphate, to phosphorylate ERK1/2 and to induce monocyte and lymphocyte chemotaxis in vitro. Moreover, nitrated CXCL12 failed to induce in vivo extravasation of lymphocytes to the joint. In summary, nitration on Tyr7 under inflammatory conditions is a novel natural posttranslational regulatory mechanism of CXCL12 which may downregulate the CXCR4-mediated inflammatory and tumor-promoting activities of CXCL12.
Highlights
The chemokine CXCL12 is a member of the CXC subgroup of chemotactic cytokines, which was previously purified from cell supernatant of the murine bone marrow stromal cell line multiple sclerosis (MS)-5 [1]
Bone marrow stromal cells were cocultered with primary leukocytes and stimulated with both the cytokine interferon-γ (IFN-γ) and the Toll-like receptor 3 ligand polyinosinic:polycytidylic acid
CXCL12 was purified from the conditioned media by heparin affinity chromatography and reversed phase (RP) chromatography (Figure 1)
Summary
The chemokine CXCL12 is a member of the CXC subgroup of chemotactic cytokines, which was previously purified from cell supernatant of the murine bone marrow stromal cell line MS-5 ( its functional name stromal cell-derived factor-1/SDF-1) [1]. CXCL12 promotes the adhesion of lymphocytes to activated endothelial cells and the subsequent transendothelial migration of these leukocytes [8,9,10,11]. CXCL12 has important homeostatic functions in B cell lymphopoiesis and is www.impactjournals.com/oncotarget responsible for the homing of hematopoietic stem and progenitor cells to the bone marrow [15,16,17,18,19,20]. In contrast to other chemokines, CXCL12 is vital for embryogenesis, since CXCL12 knock-out mice are non-viable animals which die in utero or shortly after birth [16, 21] This chemokine is responsible for the trafficking of endothelial progenitors to peripheral tissues to assist in angiogenesis, wound healing and tissue repair [22,23,24]. CXCL12 plays a role in several autoimmune diseases like rheumatoid arthritis (RA) and multiple sclerosis (MS) [32,33,34]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
