title: Blunted apoptosis of erythrocytes from taurine transporter deficient mice.
abstract: In nucleated cells cellular taurine is released prior to DNA fragmentation and the breakdown of phosphatidylserine asymmetry within the plasma membrane. Similar to what is seen in nucleated cells, phosphatidylserine asymmetry is also abolished in erythrocytes exposed to osmotic shock or oxidative stress. The present study has been performed to explore the sensitivity of erythrocytes from a taurine transporter knockout mouse (taut-/-) against osmotic shock and oxidative stress. Erythrocyte cell volume was estimated from forward scatter and breakdown of phosphatidylserine asymmetry was identified by determination of annexin binding using FACS analysis. Erythrocytes from taut-/- mice were compared to erythrocytes from wild type littermates (taut+/+). Plasma concentration and erythrocyte content of taurine was significantly lower in taut-/- than in taut+/+ mice, but the intraerythrocyte taurine concentration did not exceed the plasma concentration. Hyperosmotic shock (exposure to 700 mOsm) and oxidative stress (exposure to 0.1 mM tert-butyl-hydroperoxide) significantly decreased the cell volume and increased the number of annexin binding sites of erythrocytes from both, taut-/- and taut+/+ mice. However, decrease of cell volume and increase of annexin binding was significantly blunted in erythrocytes from taut-/- mice as compared to their taut+/+ littermates. Stimulation of erythropoiesis by prior hemorrhage did not abrogate the difference between taut+/+ and taut-/- erythrocytes. The present observations point to a decreased sensitivity of mature erythrocytes from taut-/- mice to osmotic shock and oxidative stress, rendering them more resistant to apoptosis.
authors: Department of Physiology, University of Tuebingen, Germany.
authors: Philipp A
authors: PA
authors: Lang
authors: Ulrich
authors: U
authors: Warskulat
authors: Birgit
authors: B
authors: Heller-Stilb
authors: Dan Y
authors: DY
authors: Huang
authors: Almut
authors: A
authors: Grenz
authors: Svetlana
authors: S
authors: Myssina
authors: Michael
authors: M
authors: Duszenko
authors: Florian
authors: F
authors: Lang
authors: Dieter
authors: D
authors: Häussinger
authors: Volker
authors: V
authors: Vallon
authors: Thomas
authors: T
authors: Wieder
mesh_terms: D000596:Amino Acids / Q000097:blood; D000818:Animals; D017209:Apoptosis; D002352:Carrier Proteins / Q000378:metabolism; D048429:Cell Size; D004912:Erythrocytes / Q000166:cytology* / Q000378:metabolism*; D004920:Erythropoiesis; D005260:Female; D006470:Hemorrhage; D008562:Membrane Glycoproteins / Q000172:deficiency* / Q000378:metabolism; D026901:Membrane Transport Proteins; D051379:Mice; D008822:Mice, Transgenic; D009997:Osmotic Pressure; D018384:Oxidative Stress; D010718:Phosphatidylserines / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D000099247:Taurine Transporters
chemical_list: D000596:Amino Acids; D002352:Carrier Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D010718:Phosphatidylserines; D012964:Sodium; D000099247:Taurine Transporters