The immunocytes microglia in the central nervous system (CNS) were reported to play a crucial role in neurodegeneration. As a member of P2 receptors family, purinoceptor P2Y6 has attracted much attention recently. Previous studies showed that purinoceptor P2Y6 mainly contributed to microglia activation and their later phagocytosis in CNS, while in immune system, it participated in the secretion of interleukin (IL)-8 from monocytes and macrocytes. So there raises a question: whether purinoceptor P2Y6 also takes part in neuroinflammation? Thus, this review mainly concerns about the properties and roles of purinoceptor P2Y6, including (1) structure of purinoceptor P2Y6; (2) distribution and properties of purinoceptor P2Y6; (3) relationships between purinoceptor P2Y6 and microglia; (4) relationships between purinoceptor P2Y6 and immunoinflammation. Itos proposed that purinoceptor P2Y6 may play a role in neuroinflammation in CNS, although further research is still required.
Animals ; Humans ; Inflammation ; immunology ; metabolism ; Microglia ; drug effects ; metabolism ; Monocytes ; metabolism ; Phagocytosis ; physiology ; Receptors, Purinergic P2 ; chemistry ; genetics ; metabolism

In this study, we observed that lysophosphatidylglycerol (LPG) completely inhibited a formyl peptide receptor like-1 (FPRL1) agonist (MMK-1)-stimulated chemotactic migration in human phagocytes, such as neutrophils and monocytes. LPG also dramatically inhibited IL-1beta production by another FPRL1 agonist serum amyloid A (SAA) in human phagocytes. However, LPG itself induced intracellular calcium increase and superoxide anion production in human phagocytes. Keeping in mind that phagocytes migration and IL-1beta production by FPRL1 are important for the induction of inflammatory response, our data suggest that LPG can be regarded as a useful material for the modulation of inflammatory response induced by FPRL1 activation.
Chemotaxis, Leukocyte/*drug effects ; Humans ; Interleukin-1beta/*biosynthesis ; Lysophospholipids/*pharmacology ; Monocytes/drug effects/immunology/metabolism/physiology ; Neutrophils/drug effects/immunology/metabolism/physiology ; Peptides/metabolism/pharmacology ; *Phagocytes/drug effects/immunology/metabolism/physiology ; Receptors, Formyl Peptide/*metabolism ; Receptors, Lipoxin/*metabolism ; Serum Amyloid A Protein/metabolism/pharmacology

OBJECTIVETo investigate the interaction between p38 mitogen-activated protein kinase signal transduction pathway and nuclear factor (NF)-kappaB/IkappaB system on the proinflammatory cytokines release after burn trauma.

METHODSHuman monocyte line THP-1 were incubated with serum from eight healthy controls, burn sera, burn sera pretreatment with SB203580, and burn sera pretreatment with pyrrolidine dithiocarbamate (PDTC). After 24 hours incubation with serum, tumor necrosis factor (TNF)-alpha and interleukin-1beta (IL-1beta) levels in THP-1 culture supernatants were measured by ELISA. The activities of p38 MAPK and expressions of IkappaBalpha in THP-1 were measured by Western blot analysis. The EMSA method was used to characterize the binding activities of NF-kappaB and activating protein (AP)-1 in THP-1.

RESULTSIn comparison with normal controls, burn sera resulted in a significant higher level release of TNF-alpha and IL-1beta in THP-1 [(7.30 +/- 0.84) ng/ml vs (2.20 +/- 0.28) ng/ml, P < 0.05; (2.88 +/- 0.38) ng/ml vs (0.81 +/- 0.14) ng/ml, P < 0.05], which were significantly inhibited by pretreatment with SB203580 or PDTC. Burn sera showed increased activities of p38 MAPK and AP-1 in THP-1 (4728 +/- 582 vs 1291 +/- 163, P < 0.05; 946 +/- 137 vs 361 +/- 40, P < 0.05), which were abolished by pretreatment with SB203580 but not PDTC. The expression of IkappaBalpha in THP-1 incubated with burn sera was significantly decreased than those incubated with control sera (1211 +/- 115 vs 2658 +/- 318, P < 0.05), which were abolished by pretreatment with PDTC but not SB203580. Burn sera also leaded to an increased activity of NF-kappaB in THP-1 (1636 +/- 170 vs 317 +/- 32, P < 0.05), which were abolished by pretreatment with PDTC but not SB203580.

CONCLUSIONSThere are no direct interaction between p38 MAPK signal transduction pathway and NF-kappaB/IkappaB pathway. These two pathways, which regulate the production of TNF-alpha and IL-1beta in monocyte following burn trauma, are parallel and independent.

Adolescent ; Adult ; Burns ; immunology ; physiopathology ; Female ; Humans ; I-kappa B Proteins ; physiology ; Immune Sera ; pharmacology ; In Vitro Techniques ; Interleukin-1beta ; metabolism ; Male ; Middle Aged ; Monocytes ; drug effects ; physiology ; NF-KappaB Inhibitor alpha ; NF-kappa B ; metabolism ; physiology ; Signal Transduction ; Tumor Necrosis Factor-alpha ; metabolism ; p38 Mitogen-Activated Protein Kinases ; metabolism ; physiology

During chronic inflammatory response, mono- cytes/macrophages produce 92-kDa matrix metalloproteinase-9 (MMP-9), which may contribute to their extravasation, migration and tissue remodeling. Activation of peroxisome proliferator- activated factor receptor-gamma (PPAR-gamma) has been shown to inhibit MMP-9 activity. To evaluate whether ox-LDL, a PPAR-gamma activator, inhibits PMA-induced MMP-9 expression and activity, and if so, whether CD36 and PPAR-gamma are involved in this process, we investigated the effect of ox-LDL on MMP-9 expression and activity in PMA-activated human monocytic cell line U937. PMA-induced MMP-9 expression and activity were suppressed by the treatment with ox-LDL (50 micrigram/ml) or PPAR-gamma activators such as troglitazone (5 micrometer), ciglitazone (5 micrometer), and 15d- PGJ2 (1 micrometer) for 24 h. This ox-LDL or PPAR-gamma activator-mediated inhibition of micrometer P-9 activity was diminished by the pre-treatment of cells with a blocking antibody to CD36, or PGF2a (0.3 micrometer), which is a PPAR-gamma inhibitor, as well as overexpression of a dominant-negative form of CD36. Taken together, these results suggest that ox-LDL suppresses PMA-induced MMP-9 expression and activity through CD36-mediated activation of PPAR-gamma.
Antibodies, Blocking/pharmacology ; Antigens, CD36/immunology/*physiology ; Cells, Cultured ; Chromans/pharmacology ; Gelatinase B/antagonists & inhibitors/genetics/*metabolism ; Humans ; Lipoproteins, LDL/pharmacology/*physiology ; Monocytes/drug effects/*enzymology/metabolism ; NF-kappa B/antagonists & inhibitors ; PPAR gamma/*metabolism ; Prostaglandin D2/*analogs & derivatives/pharmacology ; RNA, Messenger/analysis/metabolism ; Research Support, Non-U.S. Gov't ; Tetradecanoylphorbol Acetate/antagonists & inhibitors/pharmacology ; Thiazolidinediones/pharmacology ; Transcription, Genetic/drug effects

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