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.
ASJC Scopus subject areas
Tsai, W. H., Shih, C. H., Feng, S. Y., Li, I. T., Chang, S. C., Lin, Y. C., & Hsu, H. C. (2014). CX3CL1(+) microparticles mediate the chemoattraction of alveolar macrophages toward apoptotic acute promyelocytic leukemic cells. Cellular Physiology and Biochemistry, 33(3), 594-604. https://doi.org/10.1159/000358637