Membrane fluidity increases during apoptosis of sheep ileal Peyer's patch B cells.
To investigate specific plasma membrane structural changes associated with apoptosis, whole cells and purified plasma membranes of apoptotic B cells from the ileal Peyer's patch of sheep were analyzed for their "membrane fluidity." The ileal Peyer's patch of sheep provided a large number of B cells required for plasma membrane isolation (> 5 x 10(9)). As the incidence of apoptosis increased with time of culture, the fluidity of purified plasma membranes, as measured with the fluorophore DPH (diphenylhexatriene), increased. To evaluate this phenomenon with intact cells, B cells at different apoptotic stages were fractionated on discontinuous Percoll gradients. Similar results were obtained using the fluorophore TMA-DPH (trimethylammoniumdiphenylhexatriene), which has been shown to localize specifically to the plasma membrane. Functionally, the increase in plasma membrane fluidity associated with apoptosis may represent either a mechanism to cycle phosphatidylserine to the outer leaflet, mediating phagocytic recognition of apoptotic cells, or a consequence of this event.
Jourd'heuil
D
D
Gastrointestinal Research Group, Faculty of Medicine, University of Calgary, Canada.
Aspinall
A
A
Reynolds
J D
JD
Meddings
J B
JB
D000818:Animals; D017209:Apoptosis; D001402:B-Lymphocytes / Q000502:physiology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004161:Diphenylhexatriene / Q000031:analogs & derivatives; D005260:Female; D005456:Fluorescent Dyes; D007082:Ileum / Q000166:cytology / Q000502:physiology*; D008297:Male; D008560:Membrane Fluidity; D010581:Peyer's Patches / Q000166:cytology / Q000502:physiology*; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D004161:Diphenylhexatriene; C033628:1-(4-(trimethylamino)phenyl)-6-phenylhexa-1,3,5-triene