Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P80098 (monocyte chemoattractant protein)
 1,800 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Oxidized LDL (oxLDL) is known to induce endothelial adhesion molecule and monocyte chemoattractant protein 1 expression and this is thought to be involved in monocyte recruitment into atherosclerotic lesions. oxLDL has also been found to induce macrophage proliferation. The purpose of the present study was to determine whether oxLDL might also have the ability to increase macrophage populations by inhibiting apoptosis. We found that oxLDL caused a dose-dependent inhibition of the apoptosis that occurs in cultured bone marrow-derived macrophages after macrophage colony-stimulating factor (M-CSF) withdrawal without inducing proliferation. Incubation of macrophages with either native LDL or acetylated LDL had no effect on apoptosis. The prosurvival effect of oxLDL was not inhibited by neutralizing antibodies to granulocyte-macrophage colony-stimulating factor, was maintained in mice homozygous for a mutation in the M-CSF gene, and was not due to other secreted cytokines or growth factors. oxLDL caused activation of the mitogen-activated protein kinases ERK1/2 (extracellular signal-regulated kinases 1 and 2) as well as protein kinase B (PKB), a target of phosphatidylinositol 3-kinase (PI 3-kinase). Furthermore, there was phosphorylation of two important prosurvival PKB targets, I-kappaBalpha(Ser-32) and Bad(Ser-136). The MEK inhibitors PD 98059 and U0126 blocked ERK1/2 activation but did not diminish survival. Conversely, the PI 3-kinase inhibitors LY 294002 and wortmannin blocked PKB activation, and the ability of oxidized LDL to promote macrophage survival. Taken together, these results indicate that oxLDL can directly activate a PI 3-kinase/PKB-dependent pathway that permits macrophage survival in the absence of growth factors.
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PMID:Oxidized low density lipoprotein inhibits macrophage apoptosis through activation of the PI 3-kinase/PKB pathway. 1151 69

Complement component C3a causes a robust degranulation in human mast cells. Whether C3a also stimulates chemokine production in human mast cells and what signaling pathway it activates is not known. In the present study, we demonstrate that CD34+ cell-derived primary mast cells and a human mast cell line LAD 2 express surface C3a receptors at similar levels. Furthermore, C3a caused approximately 50% internalization of cell surface C3a receptors in both cell types. We therefore used LAD 2 cells as a model to study C3a-induced biological responses and signaling in human mast cells. We found that C3a stimulated substantial degranulation and induced chemokine monocyte chemoattractant protein 1 (MCP-1/CCL2) and regulated upon activation, normal T-cell expressed and secreted (RANTES/CCL5) production in LAD 2 mast cells. C3a caused a rapid and sustained extracellular-signal-regulated kinase (ERK) phosphorylation and Akt phosphorylation in LAD 2 mast cells. Furthermore, U0126 and LY294002, which respectively inhibit MEK-induced ERK phosphorylation and PI3 kinase-mediated Akt phosphorylation had distinct effects on C3a-induced responses. Thus, U0126, which blocked C3a-induced RANTES/CCL5 production by 50.6+/-2.3%, inhibited MCP-1/CCL2 generation by 85.2+/-0.6%. In contrast, LY294002 had no effect on C3a-induced RANTES/CCL5 production but blocked MCP-1/CCL2 generation by 83.7+/-1.5%. These data demonstrate that C3a activates divergent signaling pathways to induce chemokine production in human mast cells.
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PMID:Distinct regulation of C3a-induced MCP-1/CCL2 and RANTES/CCL5 production in human mast cells by extracellular signal regulated kinase and PI3 kinase. 1560 17

The role of fibroblasts in inflammatory processes and their cross-talk with T cells is increasingly being recognized. Our aim was to explore the capacity of dermal fibroblasts to produce inflammatory chemokines potentially involved in fibrosis occurring in response to contact with polarized human T cells. Our findings indicate that the program of chemokine production by fibroblasts is differentially regulated depending on the T-helper (Th) cell subset used to activate them. Thus, Th1 and Th2 cells preferentially induced production of IFN-gamma inducible protein (IP)-10 and IL-8, respectively, whereas monocyte chemoattractant protein (MCP)-1 was equally induced by both subsets at mRNA and protein levels. Neutralization experiments indicated that membrane-associated tumour necrosis factor-alpha and IL-1 played a major role in the induction of IL-8 and MCP-1 by Th1 and Th2 cells, whereas membrane-associated IFN-gamma (present only in Th1 cells) was responsible, at least in part, for the lower IL-8 and higher IP-10 production induced by Th1 cells. The contributions of tumour necrosis factor-alpha, IL-1 and IFN-alpha were confirmed when fibroblasts were cultured separated in a semipermeable membrane from living T cells activated by CD3 cross-linking. We observed further differences when we explored signal transduction pathway usage in fibroblasts. Pharmacological inhibition of c-Jun N-terminal kinase and nuclear factor-kappaB resulted in inhibition of IL-8 mRNA transcription induced by Th1 cells but not that by Th2 cells, whereas inhibition of MEK/ERK (mitogen-activated protein kinase of extracellular signal-regulated kinase/extracellular signal-regulated kinase) and nuclear factor-kappaB resulted in inhibition of MCP-1 mRNA induced by Th2 but not by Th1 cells. Finally, no distinct differences in chemokine production were observed when the responses to T cell contact or to prototypic Th1 and Th2 cytokines were examined in systemic sclerosis versus normal fibroblasts. These findings indicate that fibroblasts have the potential to participate in shaping the inflammatory response through the activation of flexible programs of chemokine production that depend on the Th subset eliciting their response.
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PMID:Polarized subsets of human T-helper cells induce distinct patterns of chemokine production by normal and systemic sclerosis dermal fibroblasts. 1635 98

Thrombin (coagulation factor IIa) is a serine protease encoded by the F2 gene. Pro-thrombin (coagulation factor II) is cut to generate thrombin in the coagulation cascade that results in a reduction of blood loss. Procoagulant states that lead to activation of thrombin are common in bone fracture sites. However, its physiological roles and relationship with osteoblasts in bone fractures are largely unknown. We herein report various effects of thrombin on mouse osteoblastic MC3T3-E1 cells. MC3T3-E1 cells expressed proteinase-activated receptor 1 (PAR1), also known as the coagulation factor II receptor. They also produced monocyte chemoattractant protein (MCP-1), tissue factor (TF), MCSF and IL-6 upon thrombin stimulation through the PI3K-Akt and MEK-Erk1/2 pathways. Furthermore, MCP-1 obtained from thrombin-stimulated MC3T3-E1 cells induced migration by macrophage RAW264 cells. All these effects of thrombin on MC3T3-E1 cells were abolished by the selective non-peptide thrombin receptor inhibitor SCH79797. We also found that thrombin, PAR-1, MCP-1, TF as well as phosphorylated AKT and p42/44 were significantly expressed at the fracture site of mouse femoral bone. Collectively, thrombin/PAR-1 interaction regulated MCP-1, TF, MCSF and IL-6 production by MC3T3-E1 cells. Furthermore, MCP-1 induced RAW264 cell migration. Thrombin may thus be a novel cytokine that regulates several aspects of osteoblast function and fracture healing.
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PMID:Thrombin induced by the extrinsic pathway and PAR-1 regulated inflammation at the site of fracture repair. 2647 2