Klann Projects
Our research is focused on the molecular mechanisms of translational control in the brain, how they are involved in activity-dependent, long-lasting changes in neuronal function, whether these mechanisms are required for complex behaviors such as memory, and whether they are disrupted in neurodevelopmental disorders and neurodegenerative disease.
We use a number of experimental approaches to gain a greater understanding of translational control mechanisms necessary for maintaining long-lasting changes in synaptic strength and memory. Detailed biochemical and sophisticated imaging experiments are employed to delineate the molecular signaling cascades that couple receptors to the translational apparatus during long-lasting synaptic plasticity in the hippocampus, amygdala, cortex, and striatum, and whether these types of translational control are required for memory formation, social behaviors, and behavioral flexibility.
We also conduct electrophysiological, biochemical, imaging, antd behavioral studies with various knockout and transgenic mice to determine how precise genetic manipulations that either activate or abolish specific translational control mechanisms alter synaptic function and behavior. We also study how molecular signaling, translational control, synaptic plasticity, and behavior are altered in mouse models of developmental disability, autism, aging, and Alzheimer’s disease. We develop novel technologies to identify newly synthesized proteins in response to extracellular stimuli and in disease models in neurons, brain slices, and peripheral tissues.
Finally, we generate new tools and mouse models to study the role of de novo protein synthesis in normal brain function and in pathophysiology associated with neurodevelopmental and neurodegenerative disease.
TRANSLATIONAL CONTROL OF LEARNING & MEMORY
Mechanisms of translational control in synaptic plasticity and cognitive function
It has been known for many years that long-lasting forms of synaptic plasticity and long-term memory require new protein synthesis. However, until the early 2000s, little was known concerning the signaling pathways required to couple activation of various neurotransmitter receptors to the translation machinery during these processes. Our laboratory has spent many years delineating the translational control pathways that regulate eIF4E- and eIF2-dependent translation initiation during LTP, LTD, and memory formation in the hippocampus. More recently, we have focused our efforts on understanding the cell type specificity of eIF4E- and eIF2-dependent translation in the amygdala during auditory threat memory using novel conditional and inducible protein synthesis inhibitor (ciPSI) mouse lines and viruses that we have developed.
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Selected important publications since 2008:
Hoeffer, C.A., Tang, W., Wong, H., Santillan, A., Patterson, R.J., Martinez, L.A., Tejada-Simon, M.V., Paylor, R., Hamilton, S.L., and Klann, E. (2008) Removal of FKBP12 enhances mTOR/Raptor interactions, LTP, memory, and perseverative/repetitive behavior. Neuron 60: 832-845. PMCID: PMC2630531 PubMed Link
Huynh, T., Santini, E., Mojica, E., Fink, A.E., Hall, B.S., Fetcho, R.N., Grosenick, L., Deisseroth, K., LeDoux, J.E., Liston, C., and Klann, E. (2018) Activation of a novel p70 S6 kinase 1-dependent signaling cascade in the basal nucleus of the amygdala is required for the acquisition of extinction memory. Mol. Psychiatry 23: 1394-1401. PMCID: PMC5668214 PubMed Link
Shrestha, P., Ayata, P., Herrero-Vidal, P., Longo, F., Gastone, A., LeDoux, J.E., Heintz, N., and Klann, E. (2020) A cell type-specific drug-inducible protein synthesis inhibition in mice mouse elucidates the requirement for rapid neuronal translation in memory consolidation. Nat. Neurosci. 23: 281-292. PMCID: PMC7147976 Pubmed Link
Shrestha, P., Shan, Z., Marmarcz, M. Ruiz, K.S.A., Zerihoun, A.T., Juan, C.-Y., Herrero-Vidal, P.M., Pelletier, J., Heintz, N., and Klann, E. (2020) Amygdala inhibitory neurons as loci for translational control of emotional memories. Nature 586: 407-411. PMCID: PMC7572709 PubMed Link
FRAGILE X SYNDROME
Cellular and molecular basis of synaptic dysfunction and aberrant behavior in FXS
For the last fifteen years we have been determining the molecular basis for dysregulated protein synthesis in fragile X syndrome (FXS) and how altered translation contributes to altered synaptic plasticity aberrant behavior in FXS model mice. We recently have extended our studies on altered translational control in FXS to studies of human tissues and cells.
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Selected important publications since 2006:
Hou, L., Antion, M.D., Hu, D., Spencer, C.M., Paylor, R.E., and Klann, E. (2006) Dynamic translational and proteasomal regulation of the fragile X mental retardation protein controls metabotropic glutamate receptor-dependent long-term depression. Neuron 51: 441-454. PMID: 16908410 PubMed Link
Bhattacharya, A., Kaphzan, H., Alvarez-Dieppa, A.C., Murphy, J.P., Pierre, P., and Klann, E. (2012) Genetic removal of p70 S6 kinase 1 corrects molecular, synaptic, and behavioral phenotypes in fragile X syndrome mice. Neuron 76: 325-337. PMCID: PMC3479445 PubMed Link
Bhattacharya, A., Mamcarz, M., Mullins, C., Choudhury, A., Boyle, R.G., Smith, D.G., Walker, D.W., and Klann, E. (2016) Targeting translation control with p70 S6 kinase 1 inhibitors to reverse phenotypes in fragile x syndrome mice. Neuropsychopharmacology 41: 1991-2000. PMCID: PMC4908636 PubMed Link
Santini, E., Huynh, T.N., Longo, F., Koo, S.Y., Mojica, E., D’Andrea, L., Bagni, C., and Klann, E. (2017) Reducing eIF4E-eIF4G interactions restores the balance between protein synthesis and actin dynamics in fragile X syndrome model mice. Sci. Signal., 10: eaan0665. PMCID: PMC5858943 PubMed Link
NEURODEVELOPMENTAL DISORDERS
Cellular and molecular basis of synaptic dysfunction and aberrant behavior in FXS
In addition to fragile X syndrome, we also have conducted studies to determine whether the signaling cascades that normally are required for long-lasting synaptic plasticity and memory are altered in mouse models of several developmental disorders, including Down syndrome, Angelman syndrome, and tuberous sclerosis complex. In addition, studies from our laboratory indicate that altered translational control underlies altered synaptic function and aberrant behavior in mouse models of monogenic and non-syndromic autism spectrum disorder (ASD). We also have been developing new mouse models with altered translation control and have found that they exhibit a range of autistic endophenotypes.
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Selected important publications since 2006::
Kaphzan, H., Buffington, S.A., Jung, J.I., Rasband, M.N., and Klann, E. (2011) Alterations in intrinsic membrane properties and the axon initial segment in a mouse model of Angelman syndrome. J. Neurosci. 31: 17637-17648. PMCID: PMC3483031 PubMed Link
Santini, E., Huynh, T.N., MacAskill, A.F., Carter, A.G., Pierre, P., Ruggero, D., Kaphzan, H., and Klann, E. (2013) Exaggerated translation causes synaptic and behavioral aberrations associated with autism. Nature 493: 411-415. PMCID: PMC3548017 PubMed Link
Kaphzan, H., Buffington, S.A., Ramaraj, A.B., Lingrel, J.B., Rasband, M.N., Santini, E., and Klann, E. (2013) Genetic reduction of the a1 subunit of Na/K-ATPase corrects multiple hippocampal phenotypes in Angelman syndrome mice. Cell Rep. 4: 1-8. PMCID: PMC3756897 PubMed Link
Santini, E., Turner, K.L., Ramaraj, A.B., Klann, E.*, and Kaphzan, H.* (2015) Mitochondrial superoxide contributes to hippocampal synaptic dysfunction and memory deficits in Angelman syndrome model mice. J. Neurosci. 35: 16213-16230. *equal contribution. PMCID: PMC4682786 PubMed Link
NEURODEGENERATIVE DISEASE
Cellular and molecular basis of synaptic failure and memory impairments in aging and AD
Although many years ago we found that reactive oxygen species (ROS) are required for full expression of hippocampal LTP and memory, it is clear that the aged and diseased brain handle ROS much differently as many studies have pointed to a role for excessive ROS and oxidative stress in age-related cognitive decline and impaired memory associated with Alzheimer’s disease (AD). We have studied the role of ROS in aging-related impairments in LTP and memory that are associated with normal aging, and have conducted studies to that ROS derived from mitochondria are responsible for oxidative stress-induced impairments in synaptic plasticity and memory in mice that model AD. In addition, we have identified signaling pathways that are activated as part of the integrated stress response (ISR) in response to soluble amyloid-beta and in AD model mice. Notably, we have found that prolonged activation of these pathways results in altered translational control, which contributes to synaptic dysfunction and memory deficits in AD model mice.
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Selected important publications since 2009:
Ma, T., Hoeffer, C.A., Wong, H., Massaad, C.A., Zhou, P., Iadecola, C., Murphy, M.P., Pautler, R.G., and Klann, E. (2011) Amyloid b-induced impairments in hippocampal synaptic plasticity are rescued by decreasing mitochondrial superoxide. J. Neurosci. 31: 5589-5595. PMCID: PMC3095121 PubMed Link
Ma, T., Trinh, M.A., Wexler, A.J., Bourbon, C., Gatti, E., Pierre, P., Cavener, D.R., and Klann, E. (2013) Suppression of eIF2a kinases alleviates Alzheimer’s disease-related plasticity and memory deficits. Nat. Neurosci. 16: 1299-1305. PMCID: PMC3756900 PubMed Link
Ma, T., Chen, Y., Vingtdeux, V., Zhao, H., Viollet, B., Marambaud, P., and Klann, E. (2014) Inhibition of AMP-activated protein kinase signaling alleviates impairments in hippocampal synaptic plasticity induced by amyloid b. J. Neurosci. 34: 12230-12238. PMCID: PMC4152616 PubMed Link
Oliveira, M.M., Lourenco, M.V., Longo, F., Kasica, N., Yang, W., Ureta, G., Medonca, P.H.J., Bernales, S., Ma, T., De Felice, F.G., Klann, E.*, and Ferreira, S.T.* (2021) Correction of eIF2-dependent defects in brain protein synthesis, synaptic plasticity and memory in mouse models of Alzheimer’s disease. Sci. Signal. 14: eabc5429. *equal contribution. PMCID: in progress.
Use of ‘omics to Identify Translating mRNAs and Newly Synthesized Proteins in Memory and Disease
Development of techniques to identify translating mRNAs and newly synthesized proteins in the nervous system
We have used translational ribosome affinity profiling (TRAP) and ribosome profiling to identify mRNA being translated during memory formation and mRNAs that are being translated inappropriately in disease models. In addition, we have developed new techniques utilizing surface sensing of translation (SUnSET) and bioorthogonal noncanonical amino acid tagging (BONCAT) coupled with stable isotope labeling by amino acid in cell culture (SILAC) to selectively isolate and quantify de novo proteins synthesized within a specified temporal window. We have used this approach to determine the identity alterations in newly synthesized proteins in striatal neurons treated with antipsychotics, and in adult brain slices from fragile X syndrome and Alzheimer’s disease model mice.
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Selected important publications since 2014:
Bowling, H., Zhang, G., Bhattacharya, A., Perez-Cuesta, L.M., Deinhardt, K., Hoeffer, C.A., Neubert, T.A., Gan, W.-B., Klann, E.*, and Chao, M.V.* (2014) Antipsychotics enhance neuronal morphological complexity via mTORC1-dependent translation. Sci. Signal. 7: ra4. *equal contribution. PMCID: PMC4063438 PubMed Link
Bowling, H., Bhattacharya, A., Zhang, G., Alam, D., Lebowitz, J.Z., Aryal, S., Bohm- Levine, N., Lin, D., Singha, P., Puckett, R., Zhou, L., Sharp, K., Kirshenbaum, K., Berry-Kravis, E., Neubert, T.A., and Klann, E. (2019) Altered steady state and activity-dependent de novo protein expression in fragile X syndrome. Nat. Commun. 10: 1710. PMCID: PMC6461708 PubMed Link
Ostroff, L.E., Santini, E., Sears, R., LeDoux, J.E., Lhakhang, T., Tsingos, A., Heguy, A., and Klann, E. (2019) Axon TRAP reveals learning-associated alterations in cortical axonal mRNAs in the lateral amygdala. eLife 8: e51607. PMCID: PMC6924958 PubMed Link
Aryal, S., Longo, F. and Klann, E. (2021) Genetic removal of p70 S6K1 corrects coding sequence length dependent alterations in mRNA translation in fragile X syndrome mice. Proc. Natl. Acad. Sci. USA 118: e2001681118. PMCID: PMC8106352 PubMed Link
Elder, M.K., Erdjument-Bromage, H., Oliveira, M.M., Mamcarz, M., Neubert, T.A., and, Klann, E. (2020) Dysregulation of the de novo proteome accompanies pathology progression in the APP/PS1 mouse model of Alzheimer’s disease. Commun. Biol. 4: 823. PMCID: in progress.