Reversal of learning deficits in a Tsc2+/- mouse model of tuberous sclerosis.
Tuberous sclerosis is a single-gene disorder caused by heterozygous mutations in the TSC1 (9q34) or TSC2 (16p13.3) gene and is frequently associated with mental retardation, autism and epilepsy. Even individuals with tuberous sclerosis and a normal intelligence quotient (approximately 50%) are commonly affected with specific neuropsychological problems, including long-term and working memory deficits. Here we report that mice with a heterozygous, inactivating mutation in the Tsc2 gene (Tsc2(+/-) mice) show deficits in learning and memory. Cognitive deficits in Tsc2(+/-) mice emerged in the absence of neuropathology and seizures, demonstrating that other disease mechanisms are involved. We show that hyperactive hippocampal mammalian target of rapamycin (mTOR) signaling led to abnormal long-term potentiation in the CA1 region of the hippocampus and consequently to deficits in hippocampal-dependent learning. These deficits included impairments in two spatial learning tasks and in contextual discrimination. Notably, we show that a brief treatment with the mTOR inhibitor rapamycin in adult mice rescues not only the synaptic plasticity, but also the behavioral deficits in this animal model of tuberous sclerosis. The results presented here reveal a biological basis for some of the cognitive deficits associated with tuberous sclerosis, and they show that treatment with mTOR antagonists ameliorates cognitive dysfunction in a mouse model of this disorder.
Ehninger
Dan
D
Department of Neurobiology, Brain Research Institute, University of California, Los Angeles, 695 Charles E. Young Drive South, Los Angeles, California 90095, USA.
Han
Sangyeul
S
Shilyansky
Carrie
C
Zhou
Yu
Y
Li
Weidong
W
Kwiatkowski
David J
DJ
Ramesh
Vijaya
V
Silva
Alcino J
AJ
D000818:Animals; D001522:Behavior, Animal; D003072:Cognition Disorders / Q000235:genetics; D005260:Female; D006579:Heterozygote; D006624:Hippocampus / Q000378:metabolism; D007858:Learning; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011494:Protein Kinases / Q000378:metabolism; D015398:Signal Transduction; D020123:Sirolimus / Q000494:pharmacology; D058570:TOR Serine-Threonine Kinases; D014402:Tuberous Sclerosis / Q000235:genetics*; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000502:physiology*
C000624654:Tsc2 protein, mouse; D000077005:Tuberous Sclerosis Complex 2 Protein; D025521:Tumor Suppressor Proteins; D011494:Protein Kinases; C546843:mTOR protein, mouse; D058570:TOR Serine-Threonine Kinases; D020123:Sirolimus