Role of CX3CL1 in the chemotactic migration of all-trans retinoic acid-treated acute promyelocytic leukemic cells toward apoptotic cells.

Background: Phagocytic clearance of apoptotic neutrophils by tissue macrophages is a crucial component in the resolution phase of acute inflammation. However, the number of tissue macrophages is low and not likely to cope satisfactorily with the excess number of dying neutrophils. Although recent studies have reported that neutrophils are able to engulf apoptotic neutrophils, the mechanisms by which living neutrophils are attracted to apoptotic neutrophils are poorly defined.

CX3CL1(+) microparticles mediate the chemoattraction of alveolar macrophages toward apoptotic acute promyelocytic leukemic cells.

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.