The primary focus of research in the Abel lab is to understand the cellular and molecular mechanisms of long-term memory storage with a focus on the mammalian hippocampus. One of the hallmarks of long-term memory storage is that it requires the synthesis of new genes and new proteins, which act to alter the strength of synaptic connections within appropriate neuronal circuits in the brain. How are the various signals acting on a neuron integrated to give rise to appropriate changes in gene expression? How are changes in gene expression maintained to sustain memories for days, months and even years? In our lab, we have focused on transcriptional co-activators such as CREB-binding protein (CBP) and p300, leading us to investigate the effects of histone acetylation and other epigenetic modifications in memory storage. Increasing histone acetylation pharmacologically by inhibiting histone deacetylase (HDAC) enzymes during memory consolidation enhances long-term memory. Of particular importance is the identification of genes regulated by epigenetic mechanisms during memory consolidation and after HDAC inhibition. Signals from synapses drive the transcriptional processes that are required for memory storage. A major challenge in the study of these synaptic signals is how the pathway specificity of synaptic plasticity is maintained in the face of diffusible second messengers, such as cyclic AMP (cAMP), and diffusible proteins, such as the catalytic subunit of protein kinase A (PKA). We are investigating the role of A-kinase anchoring proteins (AKAPs), which restrict PKA to specific subcellular locations, to define how signal transduction pathways in neurons are able to exhibit spatial specificity.
We are also investigating processes that can modulate the consolidation of long-term memory. For example, the biological function of sleep has remained elusive, but studies suggest that one function of sleep may be to mediate memory storage. First, sleep appears to facilitate the formation of hippocampus-dependent memories, and sleep is increased following training. Second, sleep appears to be regulated by many of the same molecular processes that contribute to memory storage, including the transcription factor cAMP response element-binding protein (CREB) and the PKA signaling pathway. By using conditional genetic approaches and gene expression studies, we are striving to elucidate the machinery underlying sleep/wake regulation and define the role of sleep in the consolidation of long-term memory. Our studies also reveal that sleep deprivation impairs memory consolidation and synaptic plasticity by impairing signaling through the cAMP pathway.
Cognitive deficits accompany many neurological, psychiatric and neurodevelopmental disorders. We are interested in determining how our knowledge of the cellular and molecular mechanisms of synaptic plasticity and memory storage can help us understand the cognitive deficits that are seen in patients with schizophrenia, autism and intellectual disability. Recent evidence suggests that disturbances in specific intracellular signaling pathways may contribute to disorders and we are working to model endophenotypes of these disorders in mice. With these translational approaches, we hope to identify novel targets for the development of new therapeutics to treat psychiatric and neurodevelopmental disorders.
Dr. Abel will be accepting psychology graduate students for admission in fall 2013.
Biology Graduate Group; Psychology Graduate Group
Halassa, M. M., Florian, C., Fellin, T., Munoz, J. R., Abel, T., Haydon, P. G. and Frank, M. G. (2009). Astrocytic modulation of sleep homeostasis and cognitive consequences of sleep loss. Neuron 61: 213-219. PMCID: PMC2673052
Vecsey, C. G., Baille, G., Jaganath, D., Havekes, R., Daniels, A., Wimmer, M., Huang, T., Brown, K., Li, X.-Y., Descalzi, G., Kim, S. S., Chen, T., Shang, Y.-Z., Zhuo, M., Houslay, M. D. and Abel, T. (2009). Sleep deprivation impairs cAMP signaling in the hippocampus. Nature 461: 1122-1125. PMCID: PMC2783639
Florian, C., Vecsey, C. G., Halassa, M. M., Haydon, P. G. and Abel, T. (2011). Astrocyte-derived adenosine and A1 receptor activity contribute to sleep loss-induced deficits in hippocampal synaptic plasticity and memory in mice. Journal of Neuroscience 31: 6956-6962. PMCID: PMC3140051
Peixoto, L. and Abel, T. (2012). The role of histone acetylation in memory formation and cognitive impairments. Neuropsychopharmacology, in press.
Hawk, J. D., Bookout, A. L., Poplawski, S. G., Bridi, M., Rao, A. J., Sulewski, M. E., Kroener, B. T., Mangelsdorf, D. J. and Abel, T. (2012). Nr4a nuclear receptors support memory enhancement by histone deacetylase inhibitors. Journal of Clinical Investigation, in press.
Huang, T., McDonough, C. and Abel, T. (2006). Compartmentalized PKA signaling events are required for synaptic tagging and capture during hippocampal LTP. European Journal of Cell Biology 85: 635-642.
Wood, M. A., Kaplan, M. P., Park, A., Blanchard, E. J., Oliveira, A. M. M., Lombardi, T. L. and Abel, T. (2005). Transgenic mice expressing a truncated form of CREB-binding protein (CBP) exhibit deficits in hippocampal synaptic plasticity and memory storage. Learning & Memory 12: 111-119.
Lattal, K. M. and Abel, T. (2004). Behavioral impairments caused by injections of the protein synthesis inhibitor anisomycin after contextual retrieval reverse with time. Proceedings of the National Academy of Sciences 101: 4667-4672.
Graves, L., Heller, E., Pack, A. and Abel, T. (2003). Sleep deprivation selectively impairs memory consolidation for contextual fear conditioning. Learning & Memory 10: 168-176.
Bucan, M. and Abel, T. (2002). The mouse: Genetics meets behavior. Nature Reviews Genetics 3:114-123.
Abel, T. and Lattal, K. M. (2001). Molecular mechanisms of memory acquisition, consolidation and retrieval. Current Opinion in Neurobiology 11: 180-187.