Quantum Proteolytic Activation of Chemokine CCL15 by Neutrophil Granulocytes Modulates Mononuclear Cell Adhesiveness

Abstract

Monocyte infiltration into inflammatory sites is generally preceded by neutrophils. We show here that neutrophils may support this process by activation of CCL15, a human chemokine circulating in blood plasma. Neutrophils were found to release CCL15 proteolytic activity in the course of hemofiltration of blood from renal insufficiency patients. Processing of CCL15 immunoreactivity (IR) in the pericellular space is suggested by a lack of proteolytic activity in blood and blood filtrate, but a shift of the retention time (tR) of CCL15-IR, detected by chromatographic separation of CCL15-IR in blood and hemofiltrate. CCL15 molecules with N-terminal deletions of 23 (Δ23) and 26 (Δ26) aa were identified as main proteolytic products in hemofiltrate. Neutrophil cathepsin G was identified as the principal protease to produce Δ23 and Δ26 CCL15. Also, elastase displays CCL15 proteolytic activity and produces a Δ21 isoform. Compared with full-length CCL15, Δ23 and Δ26 isoforms displayed a significantly increased potency to induce calcium fluxes and chemotactic activity on monocytes and to induce adhesiveness of mononuclear cells to fibronectin. Thus, our findings indicate that activation of monocytes by neutrophils is at least in part induced by quantum proteolytic processing of circulating or endothelium-bound CCL15 by neutrophil cathepsin G.

Targeting the PI3K/AKT Pathway for the Treatment of Prostate Cancer

“…Studies indicate that p110β is not primarily regulated by tyrosine kinase receptors, but by G-proteincoupled receptors. Chemokines have been implicated in prostate carcinogenesis, by impacting cancer cell proliferation, survival, adhesion, and invasion (44) through their activation of G-protein-coupled transmembrane-spanning receptors activating downstream p110β signaling (45). Chemokines such as CCL2 (monocyte chemoattractant protein; MCP1) have also been reported to stimulate monocyte/macrophage migration into tumors, potentially fueling tumor growth, and to play a role in angiogenesis.…”

Identification and Characterization of Circulating Variants of CXCL12 from Human Plasma: Effects on Chemotaxis and Mobilization of Hematopoietic Stem and Progenitor Cells

“…Isolated material was applied to a stainless steel multiple sample tray as an admixture with sinapinic acid using the dried drop technique [10]. Measurements were performed in linear mode.…”

“…Processing of full-length CXCL12 by blood cells Peripheral blood mononuclear cells (PBMCs), polymorphonuclear neutrophils (PMNs), and thrombocytes were isolated according to established methods [10]. PBMCs and PMNs were isolated from 30 mL venous blood mixed with 10 mL hydroxyethyl starch (Plasmasteril; Fresenius, Bad Homburg, Germany).…”

“…CXCL12 molecules were prepared by solid-phase peptide synthesis as previously described [10]. The purified products were characterized by HPLC, capillary zone electrophoresis, electrospray mass spectrometry, and sequence analysis.…”

Identification of Human Cathepsin G As a Functional Target of Boswellic Acids from the Anti-Inflammatory Remedy Frankincense

“…After release into the plasma, it cleaves extracellular matrix proteins, including laminin, proteoglycans, collagen, fibronectin, and elastin (13,14), implying a role in local destruction of connective tissue at sites of injury. CatG also processes chemokines (11,15,16), functioning as chemoattractant for T cells and other leukocytes (17), and modulates integrin clustering on neutrophils (18). Moreover, catG stimulates platelets via the protease-activated receptor-4 for aggregation and secretion (19) and acts as chemotactic agonist for the formyl peptide receptor on phagocytic leukocytes (20).…”