Differential expression of three T lymphocyte-activating CXC chemokines by human atheroma-associated cells

Activated T lymphocytes accumulate early in atheroma formation and persist at sites of lesion growth and rupture, suggesting that they may play an important role in the pathogenesis of atherosclerosis. Moreover, atherosclerotic lesions contain the Th1-type cytokine IFN-gamma, a potentiator of atherosclerosis. The present study demonstrates the differential expression of the 3 IFN-gamma-inducible CXC chemokines--IFN-inducible protein 10 (IP-10), monokine induced by IFN-gamma (Mig), and IFN-inducible T-cell alpha chemoattractant (I-TAC)--by atheroma-associated cells, as well as the expression of their receptor, CXCR3, by all T lymphocytes within human atherosclerotic lesions in situ. Atheroma-associated endothelial cells (ECs), smooth muscle cells (SMCs), and macrophages (MO) all expressed IP-10, whereas Mig and I-TAC were mainly expressed in ECs and MO, as detected by double immunofluorescence staining. ECs of microvessels within lesions also expressed abundant I-TAC. In vitro experiments supported these results and showed that IL-1beta, TNF-alpha, and CD40 ligand potentiated IP-10 expression from IFN-gamma-stimulated ECs. In addition, nitric oxide (NO) treatment decreased IFN-gamma induction of IP-10. Our findings suggest that the differential expression of IP-10, Mig, and I-TAC by atheroma-associated cells plays a role in the recruitment and retention of activated T lymphocytes observed within vascular wall lesions during atherogenesis

Genomic organization of the CC chemokine MIP-3 alpha/CCL20/LARC/EXODUS/SCYA20, showing gene structure, splice variants, and chromosome localization

Copyright © 2001 Academic Press. All rights reserved.We describe the genomic organization of a recently identified CC chemokine, MIP3α/CCL20 (HGMW-approved symbol SCYA20). The MIP-3α/CCL20 gene was cloned and sequenced, revealing a four exon, three intron structure, and was localized by FISH analysis to 2q35–q36. Two distinct cDNAs were identified, encoding two forms of MIP-3α/CCL20, Ala MIP-3α/CCL20 and Ser MIP-3α/CCL20, that differ by one amino acid at the predicted signal peptide cleavage site. Examination of the sequence around the boundary of intron 1 and exon 2 showed that use of alternative splice acceptor sites could give rise to Ala MIP-3α/CCL20 or Ser MIP-3α/CCL20. Both forms of MIP-3α/CCL20 were chemically synthesized and tested for biological activity. Both flu antigen plus IL-2-activated CD4+ and CD8+ T lymphoblasts and cord blood-derived dendritic cells responded to Ser and Ala MIP-3α/CCL20. T lymphocytes exposed only to IL-2 responded inconsistently, while no response was detected in naive T lymphocytes, monocytes, or neutrophils. The biological activity of Ser MIP-3α/CCL20 and Ala MIP-3α/CCL20 and the tissue-specific preference of different splice acceptor sites are not yet known.Robin T. Nelson, James Boyd, Ronald P. Gladue, Timothy Paradis, Ranjeny Thomas, Ann C. Cunningham, Paul Lira, William H. Brissette, Lisa Hayes, Lynn M. Hames, Kuldeep S. Neote and Shaun R. McCollhttp://www.elsevier.com/wps/find/journaldescription.cws_home/622838/description#descriptio

Expression of rat I-TAC/CXCL11/SCYA11 during central nervous system inflammation: comparison with other CXCR3 ligands

© 2007 United States and Canadian Academy of PathologyThe chemokines are a large gene superfamily with critical roles in development and immunity. The chemokine receptor CXCR3 appears to play a major role in the trafficking of activated Th1 lymphocytes. There are at least three major ligands for CXCR3: mig/CXCL9, IP-10/CXCL10 and I-TAC/CXCL11, and of these three ligands, CXCL11 is the least well-characterized. In this study, we have cloned a rat ortholog of CXCL11, evaluated its function, and examined its expression in the Th-1-mediated disease, experimental autoimmune encephalomyelitis (EAE) in the rat. Based on its predicted primary amino-acid sequence, rat I-TAC/CXCL11 was synthesized and shown to induce chemotaxis of activated rat T lymphocytes in vitro and the in vivo migration of T lymphocytes when injected into the skin. I-TAC/CXCL11 expression, as determined by RT-PCR, increased in lymph node and spinal cord tissue collected from rats in which EAE had been actively induced, and in spinal cord tissue from rats in which EAE had been passively induced. The kinetics of expression were similar to that of CXCR3 and IP-10/CXCL10, although expression of both CXCR3 and IP-10/CXCL10 was more intense than that of I-TAC/CXCL11 and increased more rapidly in both lymph nodes and the spinal cord. Only minor levels of expression of the related chemokine mig/CXCL9 were observed. Immunohistochemistry revealed that the major cellular source of I-TAC/CXCL11 in the central nervous system (CNS) during EAE is likely to be the astrocyte. Together, these data indicate that I-TAC/CXCL11 is expressed in the CNS during the clinical phase of EAE. However, the observation that I-TAC/CXCL11 is expressed after receptor expression is detected suggests that it is not essential for the initial migration of CXCR3-bearing cells into the CNS.Shaun R McColl, Surendran Mahalingam, Maria Staykova, Laurie A Tylaska, Katherine E Fisher, Christine A Strick, Ronald P Gladue, Kuldeep S Neote and David O Willenbor