This study was aimed to explore the expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 in bcr/abl fusion gene positive CML cells, and to study the effects of P210(bcr/abl) fusion protein tyrosine kinase on expression of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNAs in chronic myeloid leukemia cells. The expression levels of MIP-1alpha, MCP-1 and their receptors CCR-1, CCR-2 mRNA were detected by semi-quantitative RT-PCR in bcr/abl negative cells, bcr/abl positive cells, and P210(bcr/abl)-Rb-C-Box positive cells. The results showed that MIP-1alpha and CCR-1 mRNAs were expressed in bcr/abl negative cells, but not in positive cells. Both MCP-1 and CCR-2 mRNA cannot be detected in both bcr/abl positive and negative cells. After inhibiting P210(bcr/abl) tyrosine kinase activity by Rb-C-Box, expressions of MIP-1alpha and CCR-1 mRNAs were restored to normal (similar to P210(bcr/abl) negative cells). It is concluded that P210(bcr/abl) fusion protein inhibits the expression of MIP-1alpha and CCR-1 in chronic myeloid leukemia cells, but does not inhibit MCP-1 and CCR-2 mRNA expressions in these leukemia cells.
Chemokine CCL2 ; biosynthesis ; genetics ; Chemokine CCL3 ; Chemokine CCL4 ; Humans ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; metabolism ; Macrophage Inflammatory Proteins ; biosynthesis ; genetics ; Receptors, CCR1 ; Receptors, CCR2 ; Receptors, Chemokine ; biosynthesis ; genetics ; Tumor Cells, Cultured

Cytokine and chemokine receptors play a key role in inflammation caused by rheumatoid arthritis (RA). Two isoforms of human CC chemokine receptor R2 (CCR2), the receptor of monocyte chemoattractant protein 1 (MCP-1), have been identified but their relative expression in fibroblast-like synoviocytes (FLS) and their contribution to inflammatory responses mediated by MCP-1 or inflammatory cytokines in patients with RA remain uncertain. We examined the pattern of expression of two CCR2 isoforms upon stimulation by proinflammatory cytokines and CD40 ligation. FLS were prepared from the synovial tissues of RA patients and cultured in the presence of MCP-1, soluble CD40 ligand (sCD40L), TGF-beta, IL-1beta, IL-18, IL-15, and LPS. CCR2A and CCR2B expression was examined by immunohistochemistry, RT-PCR and western blot analysis. IL-15, TNF-alpha and MCP-1 production was determined by ELISA. Immunohistochemistry showed that CCR2A is highly expressed in RA synovium compared with OA synovium. Transcripts of both CCR2A and CCR2B were detected in FLS. Exogenous MCP-1, CD40L, TGF-beta, and IL-15 significantly increased the expression of CCR2A but not CCR2B. Exposure of FLS to sCD40L caused strong upregulation of CCR2A but not of CCR2B protein expression. MCP-1 increased the proliferation of FLS and the production of IL-15, TNF-alpha, and IL-18. Because CCR2A is the main target of regulation by cytokines and CD40 ligation, the relatively higher expression of CCR2A on the cell surface suggests that this isoform of MCP-1 receptor functions as the principal mediator of inflammatory signals in RA FLS.
Arthritis, Rheumatoid/*metabolism ; CD40 Ligand/*pharmacology ; Cells, Cultured ; Chemokine CCL2/*pharmacology ; Chemokines/biosynthesis ; Fibroblasts/*metabolism ; Humans ; Protein Isoforms ; Receptors, CCR2/*biosynthesis ; Synovial Membrane/*pathology ; Transforming Growth Factor beta/*pharmacology

Chemokines and chemokine receptors play a role in migration of circulating leukocytes to the region of inflammation. Human LZIP is an uncharacterized transcription factor and is known to participate in leukotactin (Lkn)-1/CCL15-induced cell migration. We investigated the role of human LZIP in expression of CC chemokine receptors (CCRs) and its involvement in monocyte migration. RNase protection analysis showed that LZIP increased mRNA expression of CCR2 and CCR1 in THP-1 cells. Surface expressions of both CCR2 and CCR1 were also increased by LZIP. Results from an electrophoretic mobility shift assay showed that LZIP binds to the C/EBP element in the CCR2 promoter. LZIP also enhanced the chemotactic activities of monocyte chemoattractant protein-1/CCL2 and Lkn-1. These results suggest that LZIP regulates expression of chemokine receptors that are involved in monocyte migration.
Atherosclerosis/drug therapy/etiology ; CCAAT-Enhancer-Binding Proteins/genetics/immunology/*metabolism ; Cell Line, Tumor ; Cell Movement/drug effects/*physiology ; Chemokine CCL2/*pharmacology ; Chemokines, CC/pharmacology ; Cyclic AMP Response Element-Binding ; Humans ; Macrophage Inflammatory Proteins/pharmacology ; Monocytes/drug effects/metabolism ; Promoter Regions, Genetic ; Protein Binding ; RNA, Messenger/analysis ; Receptors, CCR1/biosynthesis/genetics ; Receptors, CCR2/*biosynthesis/genetics ; Transcriptional Activation/drug effects ; Transfection ; Transgenes