Absence of mitochondrial uncoupling protein 1 affects apoptosis in thymocytes, thymocyte/T-cell profile and peripheral T-cell number.
Our laboratory has previously demonstrated the presence of constitutively expressed mitochondrial uncoupling protein 1 in mouse thymocytes. In our endeavours to understand the role of mitochondrial uncoupling protein 1 in thymocyte function, we compared cell profiles in thymus and spleen of wild-type with those of UCP 1 knock-out mice, which in turn led to comparative investigations of apoptotic potential in thymocytes from these mice. We demonstrate that spleen cell numbers were reduced approximately 3-fold in UCP 1 knock-out mice compared to wild-type mice. We record a halving of CD8 single positive cell numbers in thymus with a significant incremental increase in CD4/CD8 double positives cell numbers in the thymus of UCP 1 knock-out mice compared to wild-type mice. These data are mirrored by an approximate halving of CD8 single positive cell numbers and a doubling of CD4/CD8 double positive cell numbers in the spleen of UCP 1 knock-out mice compared to wild-type mice. These differences are most probably explained by our observations of decreased apoptotic potential and higher ATP levels in thymocytes of UCP 1 knock-out mice when compared to wild-type controls. We conclude that constitutively expressed UCP 1 is a factor in determining T-cell population selection in mice.
Adams
Alison E
AE
School of Biochemistry and Immunology, Trinity College Dublin, Dublin 2, Ireland.
Kelly
Orlagh M
OM
Porter
Richard K
RK
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D020169:Caspases / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D005260:Female; D066298:In Vitro Techniques; D007473:Ion Channels / Q000172:deficiency* / Q000235:genetics / Q000276:immunology*; D018655:Lymphocyte Count; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D024101:Mitochondrial Proteins / Q000172:deficiency* / Q000235:genetics / Q000276:immunology*; D010101:Oxygen Consumption; D016176:T-Lymphocyte Subsets / Q000166:cytology* / Q000187:drug effects / Q000276:immunology* / Q000378:metabolism; D000071256:Uncoupling Protein 1
D007473:Ion Channels; D024101:Mitochondrial Proteins; C000604372:Ucp1 protein, mouse; D000071256:Uncoupling Protein 1; D003907:Dexamethasone; D000255:Adenosine Triphosphate; D020169:Caspases