Bcl-2 overexpression delays caspase-3 activation and rescues cerebellar degeneration in prion-deficient mice that overexpress amino-terminally truncated prion.
Prnp knockout mice that overexpress an amino-truncated form of PrPc (deltaPrP) are ataxic and display cerebellar cell loss and premature death. Studies on the molecular and intracellular events that trigger cell death in these mutants may contribute to elucidate the functions of PrPc and to the design of treatments for prion disease. Here we examined the effects of Bcl-2 overexpression in neurons on the development of the neurological syndrome and cerebellar pathology of deltaPrP. We show that deltaPrP overexpression activates the stress-associated kinases ERK1-2 in reactive astroglia, p38 and the phosphorylation of p53, which leads to the death of cerebellar neurons in mutant mice. We found that the expression of deltaPrP in cell lines expressing very low levels of PrPc strongly induces the activation of apoptotic pathways, thereby leading to caspase-3 activation and cell death, which can be prevented by coexpressing Bcl-2. Finally, we corroborate in vivo that neuronal-directed Bcl-2 overexpression in deltaPrP mice (deltaPrP Bcl-2) markedly reduces caspase-3 activation, glial activation, and neuronal cell death in cerebellum by improving locomotor deficits and life expectancy.
Nicolas
Oriol
O
Department of Cell Biology, University of Barcelona, Barcelona, Spain.
Gavín
Rosalina
R
Braun
Nathalie
N
Ureña
Jesús Mariano
JM
Fontana
Xavier
X
Soriano
Eduardo
E
Aguzzi
Adriano
A
del Río
José Antonio
JA
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D053148:Caspase 3 / Q000235:genetics / Q000378:metabolism*; D016923:Cell Death; D002478:Cells, Cultured; D002526:Cerebellar Diseases / Q000378:metabolism / Q000473:pathology*; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism / Q000473:pathology; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D009043:Motor Activity / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000502:physiology; D010641:Phenotype; D018621:PrPC Proteins / Q000235:genetics / Q000378:metabolism; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D018621:PrPC Proteins; D020033:Protein Isoforms; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D053148:Caspase 3