title: CX3CL1(+) microparticles mediate the chemoattraction of alveolar macrophages toward apoptotic acute promyelocytic leukemic cells.
abstract: OBJECTIVE
  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.
  
  
  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.
  
  
  CONCLUSIONS
  CX3CL1(+) apo-MPs released by apoptotic cells mediate the chemotactic transmigration of alveolar macrophages.
authors.affiliation: Department of Respiratory Therapy, Taipei Medical University, Taipei, Taiwan.
authors.forename: Wen-Hui
authors.initials: WH
authors.lastname: Tsai
authors.forename: Chung-Hung
authors.initials: CH
authors.lastname: Shih
authors.forename: Shan-Yu
authors.initials: SY
authors.lastname: Feng
authors.forename: I-Ting
authors.initials: IT
authors.lastname: Li
authors.forename: Shao-Chi
authors.initials: SC
authors.lastname: Chang
authors.forename: Yu-Chieh
authors.initials: YC
authors.lastname: Lin
authors.forename: Hui-Chi
authors.initials: HC
authors.lastname: Hsu
mesh_terms: D000818:Animals; D017209:Apoptosis; D045744:Cell Line, Tumor; D055252:Cell-Derived Microparticles / Q000378:metabolism* / Q000473:pathology; D054428:Chemokine CX3CL1 / Q000378:metabolism*; D002633:Chemotaxis; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000378:metabolism* / Q000473:pathology; D016676:Macrophages, Alveolar / Q000378:metabolism* / Q000473:pathology; D009363:Neoplasm Proteins / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014212:Tretinoin / Q000494:pharmacology
chemical_list: C515538:CX3CL1 protein, human; D054428:Chemokine CX3CL1; C515540:Cx3cl1 protein, rat; D009363:Neoplasm Proteins; D014212:Tretinoin