Monocyte chemotactic protein 4 (MCP-4), a novel structural and functional analogue of MCP-3 and eotaxin.

Abstract

SummaryA novel human CC chemokine complementary DNA was identified in a library constructed from human fetal RNA, cloned into a baculovirus vector, and expressed in Sf9 insect cells. The mature recombinant protein that was released had the NH2-terminal sequence pyro-QPDALNVPSTC...and consisted of 75 amino acids. Minor amounts of two variants of 77 and 82 residues (NH2 termini: LAQPDA...and FNPQGLAQPDA...) were released as well. The novel chemokine was designated monocyte chemotactic protein 4 (MCP-4) and the variants were designated (LA)MCP-4 and (FNPQGLA)MCP-4. MCP-4 shares the pyroglutamic acidproline NH2-terminal motif and 56-61% sequence identity with the three known monocyte chemotactic proteins and is 60% identical to eotaxin. It has marked functional similarities to MCP-3 and eotaxin. Like MCP-3, MCP-4 is a chemoattractant of high efficacy for monocytes and T lymphocytes. On these cells, it binds to receptors that recognize MCP-1, MCP-3, and RANTES. On eosinophils, MCP-4 has similar efficacy and potency as MCP-3, RANTES, and eotaxin. It shares receptors with eotaxin and shows full cross-desensitization with this eosinophil-selective chemokine. Of the two variants, only (LA)MCP-4 could be purified in sufficient quantities for testing and was found to be at least 30-fold less potent than MCP-4 itself. This suggests that the 75-residue form with the characteristic NH 2 terminus of an MCP is the biologically relevant species.T he number of chemokines of the CC subfamily has grown considerably during the past few years, and important new information has been gathered about their activities on different types of leukocytes (1). Of particular interest were the findings that the monocyte chemotactic proteins (MCPs) are not only effective on monocytes (2-4), but also attract CD4 + and CD8 + T lymphocytes (5, 6) and basophil leukocytes (7-10). MCP-3 (10) and R_ANTES (11) were also shown to be powerful attractants of eosinophil leukocytes and, most recently, eotaxin, a CC chemokine with marked sequence similarity to MCP-3, was found to share this activity and to be unusually selective for eosinophils (12-14).In a program aiming at the discovery of human genes by large-scale sequencing of partial cDNA clones, a novel chemokine cDNA was identified in a library constructed from human fetal mRNA. The full-length cDNA was cloned into a baculovirus expression vector, and the chemokine obtained was designated CK[310. A screening for the induction of changes of the cytosolic free Ca 2+ concentration ([Ca2+]i) in human blood monocytes showed that CK[310 was as effective as MCP-1 and MCP-3. We compared its biological activity on human monocytes, neutrophils, eosinophils, and T lymphocytes with that ofMCP-1, MCP-2, MCP-3, RANTES, MIP-lc~, and eotaxin, and found that CK[310 is functionally very similar to MCP-3. Since the novel CC chemokine also shares marked sequence identity to the monocyte chemotactic proteins, we adopted the term MCP-4. This designation is actually not new. A 153-bp PCR fragment was previously cloned from h...

Receptor reserve analysis of the human CCR3 receptor in eosinophils and CCR3-transfected cells

“…A similar reduction was observed in mice deficient in eotaxin [14]. Although less is known about the in vivo role of other CCR3 ligands, such as eotaxin-2 [15], MCP-4 [16], RANTES, and MCP-3 [8], the information accumulated to date indicates that the development of CCR3 receptor antagonists represents a possible approach to blocking pulmonary eosinophilic inflammation, which is characteristic of asthma [17,18]. Toward this end, it is important to understand the pharmacology of interaction of CCR3 with its ligands, such that appropriate assays are used to most readily identify the antagonists.…”

“…Toward this end, it is important to understand the pharmacology of interaction of CCR3 with its ligands, such that appropriate assays are used to most readily identify the antagonists. Several chemokines have been described to bind to CCR3 on human eosinophils [7,8,12] and induce chemotaxis in vitro [12,15,16,19,20]. Other measurements of receptor-activated intracellular events such as increases in intracellular calcium levels [7,12,15,16,[20][21][22][23], production of reactive oxygen [15,[21][22][23][24], histamine release [15], and actin polymerization [22][23][24] have also been used to characterize CCR3 ligands.…”

Induction of CCL13 expression in synovial fibroblasts highlights a significant role of oncostatin M in rheumatoid arthritis

“…The CC chemokine CCL13 was recently identified from a human complementary DNA library and shown to direct the migration of eosinophils, monocytes, and T lymphocytes through several chemokine receptors, including CCR2 and CCR3 (29,30). The role of CCL13 in disease is less well defined, but recent studies suggest that it might be involved in inflammatory cell recruitment in allergic disorders such as asthma and atopic dermatitis (31,32).…”

Eosinophil-active chemokines: assessment of in vivo activity

“…In agreement with their ability to bind to and activate the CCR-3 receptor, RANTES, MCP-3, MCP-4 and eotaxin are effective activators of eosinophils in vitro (18)(19)(20)(21). Thus, these chemokines have been shown to elevate intracellular calcium levels in eosinophils and induce chemotaxis, mediator release and the production of oxygen radicals.…”