CX3CL1(+) Microparticles Mediate the Chemoattraction of Alveolar Macrophages toward Apoptotic Acute Promyelocytic Leukemic Cells

Abstract

Background/Aims: During the resolution phase of inflammation, release of “find-me” signals by apoptotic cells is crucial in the chemoattraction of macrophages toward apoptotic cells for subsequent phagocytosis, in which microparticles derived from apoptotic cells (apo-MPs) are involved. A recent study reports that CX3CL1 is released from apoptotic cells to stimulate macrophages chemotaxis. In this study, we investigated the role of CX3CL1 in the apo-MPs in the cell-cell interaction between alveolar macrophage NR8383 cells and apoptotic all-trans retinoic acid-treated NB4 (ATRA-NB4) cells. Methods/Results: Apoptotic ATRA-NB4 cells and their conditioning medium (CM) enhanced the chemoattraction of NR8383 cells as well as their phagocytosis activity in engulfing apoptotic ATRA-NB4 cells. The levels of CX3CL1(+) apo-MPs and CX3CL1 were rapidly elevated in the CM of ATRA-NB4 cell culture after induction of apoptosis. Both exogenous CX3CL1 and apo-MPs enhanced the transmigration of NR8383 cells toward apoptotic ATRA-NB4 cells. This pro-transmigratory activity was able to be partially inhibited either by blocking the CX3CR1 (CX3CL1 receptor) of NR8383 cells with its specific antibody or by blocking the surface CX3CL1 of apo-MPs with its specific antibody before incubating these apo-MPs with NR8383 cells. Conclusion: CX3CL1(+) apo-MPs released by apoptotic cells mediate the chemotactic transmigration of alveolar macrophages.

Differential Proteomic Analysis of Syncytiotrophoblast Extracellular Vesicles from Early-Onset Severe Preeclampsia, using 8-Plex iTRAQ Labeling Coupled with 2D Nano LC-MS/MS

“…Both eukaryotic and prokaryotic cells release extracellular vesicles (EVs) to their environment, which are spherical particles enclosed by a phospholipid bilayer and now thought to contribute to both physiology and pathology [32,33]. Currently, there has no absolute consensus on classification, isolation and detection of EVs.…”

Cell-Derived Microparticles in Patients with Type 2 Diabetes Mellitus: a Systematic Review and Meta-Analysis

“…MPs derived from activated or apoptotic endothelial cells varied in immunophenotype [67][68][69]. Generally, CD31 and CD105 were used as markers of apoptotic EMPs, while CD62E was used as the marker of activated EMPs [67].…”

The Sound of Silence

“…Specifically, FKN is released by apoptotic cells to recruit professional phagocytes to the site of cell death (Sokolowski, Chabanon-Hicks, Han, Heffron, & Mandell, 2014; Truman et al, 2008; Tsai et al, 2014). Beyond simple recruitment, however, FKN can also enhance the ability of macrophages and microglia to execute their phagocytic functions (Miksa, Amin, Wu, Ravikumar, & Wang, 2007).…”

“…Membrane blebbing is driven by caspase-mediated activation of the Rho-associated kinase ROCK I (Coleman et al, 2001; Sebbagh et al, 2001). These approximately five micron particles function as chemoattractants, recruiting monocytes to sites of apoptosis (Segundo et al, 1999) possibly based on the classic attractants they harbor on their membranes (Tsai et al, 2014). Upon calcium-activated release, these microblebs spread out through the intercellular spaces, potentially traveling great distances within the organism (Hoang, Rampon, Freyssinet, Vriz, & Kerbiriou-Nabias, 2011).…”