Taurine deficiency and apoptosis: findings from the taurine transporter knockout mouse.
Apoptosis is characterized by cell shrinkage, nuclear condensation, DNA-fragmentation and apoptotic body formation. Compatible organic osmolytes, e.g. taurine, modulate the cellular response to anisotonicity and may protect from apoptosis. Taurine transporter knockout mice (taut-/- mice) show strongly decreased taurine levels in a variety of tissues. They develop clinically important age-dependent diseases and some of them are characterized by apoptosis. Increased photoreceptor apoptosis leads to blindness of taut-/- mice at an early age. The taurine transporter may not be essential for the differentiation of photoreceptor cells, but many mature cells do not survive without an intact taurine transporter. The olfactory epithelium of taut-/- mice also exhibits structural and functional abnormalities. When compared with wild-types, taut-/- mice have a significantly higher proliferative activity of immature olfactory receptor neurons and an increased number of apoptotic cells. This is accompanied by electrophysiological findings indicating a reduced olfactory sensitivity. Furthermore, taut-/- and taut+/- mice develop moderate unspecific hepatitis and liver fibrosis beyond 1 year of age where hepatocyte apoptosis and activation of the CD95 system are pronounced.
Warskulat
Ulrich
U
Department of Gastroenterology, Hepatology and Infectiology, Heinrich-Heine-University Düsseldorf, Germany. warskulat@med.uni-duesseldorf.de
Borsch
Elena
E
Reinehr
Roland
R
Heller-Stilb
Birgit
B
Roth
Christian
C
Witt
Martin
M
Häussinger
Dieter
D
D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism*; D008107:Liver Diseases / Q000378:metabolism* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000172:deficiency* / Q000235:genetics; D026901:Membrane Transport Proteins / Q000172:deficiency* / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D009135:Muscular Diseases / Q000378:metabolism* / Q000473:pathology; D013654:Taurine / Q000378:metabolism*; D019014:fas Receptor / Q000378:metabolism*; D000099247:Taurine Transporters
D051017:Apoptosis Regulatory Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D013654:Taurine; D019014:fas Receptor; D000099247:Taurine Transporters