TY - JOUR
T1 - Discrimination of early and late apoptotic cells by NBD-phosphatidylserine- labelling and time-lapse observation of phagocytosis of apoptotic cells by macrophages
AU - Saijo, Shinji
AU - Nagata, Kisaburo
AU - Masuda, Junko
AU - Matsumoto, Isamu
AU - Kobayashi, Yoshiro
PY - 2007/3/1
Y1 - 2007/3/1
N2 - Since free apoptotic cells are not detected in normal tissues, it is generally believed that apoptotic cells are removed as soon as they appear in vivo. A fluorescent derivative of phosphatidylserine, 1-palmitoyl-2-[6-[(7- nitro-2-1,3-benzoxadiazol-4-yl) amino]hexanoyl]-sn-glycero-3-phospho-L-serine (NBD-PS) is known to be incorporated into living cells, and thereafter gradually absorbed into either fatty acid-free bovine serum albumin or fetal calf serum from the outer leaflet of the cell membrane. When thymocytes were irradiated with X-ray and cultured in the presence of NBD-PS, cells became less fluorescent as apoptosis advanced, but early apoptotic cells were still positive for NBD-PS. We then co-cultured such early apoptotic thymocytes with resident peritoneal macrophages. Upon examination under a time-lapse fluorescence microscope, it was found that the attachment of early apoptotic cells to macrophages does not cause rapid phagocytosis, as compared with late apoptotic cells, suggesting the possibility that, in contrast to the widely held view, early apoptotic cells may not be quickly removed by phagocytes in vivo.
AB - Since free apoptotic cells are not detected in normal tissues, it is generally believed that apoptotic cells are removed as soon as they appear in vivo. A fluorescent derivative of phosphatidylserine, 1-palmitoyl-2-[6-[(7- nitro-2-1,3-benzoxadiazol-4-yl) amino]hexanoyl]-sn-glycero-3-phospho-L-serine (NBD-PS) is known to be incorporated into living cells, and thereafter gradually absorbed into either fatty acid-free bovine serum albumin or fetal calf serum from the outer leaflet of the cell membrane. When thymocytes were irradiated with X-ray and cultured in the presence of NBD-PS, cells became less fluorescent as apoptosis advanced, but early apoptotic cells were still positive for NBD-PS. We then co-cultured such early apoptotic thymocytes with resident peritoneal macrophages. Upon examination under a time-lapse fluorescence microscope, it was found that the attachment of early apoptotic cells to macrophages does not cause rapid phagocytosis, as compared with late apoptotic cells, suggesting the possibility that, in contrast to the widely held view, early apoptotic cells may not be quickly removed by phagocytes in vivo.
KW - Apoptotic cells
KW - Macrophages
KW - Phagocytosis
KW - Phosphatidylserine
KW - Time-lapse observation
UR - http://www.scopus.com/inward/record.url?scp=34248634609&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34248634609&partnerID=8YFLogxK
U2 - 10.1093/jb/mvm029
DO - 10.1093/jb/mvm029
M3 - Article
C2 - 17179182
AN - SCOPUS:34248634609
VL - 141
SP - 301
EP - 307
JO - Journal of Biochemistry
JF - Journal of Biochemistry
SN - 0021-924X
IS - 3
ER -