This model analyses altered hippocampal synaptic plasticity and its rescue under the Alzheimer's disease (AD) conditions, when the concentrations of AD-related peptides, such as the amyloid precursor protein intracellular domain (AICD) and amyloid beta (Aβ), are increased. The phenomenological NMDA receptor-based voltage-dependent model is used to model synaptic modifications at the CA3-CA1 synapses onto the multicompartmental CA1 pyramidal neuron. The modeling results show that partial blockade of Glu2NB-NMDAR-gated channel restores intrinsic excitability of a CA1 pyramidal neuron and rescues long-term potentiation in AICD and Aβ conditions. The model is implemented in Python and NEURON.
Experimental motivation: Accumulating experimental evidence suggests that AICD and amyloid beta play a role in modifying hippocampus function in the early stages of the disease. AICD has a strong impact on synapse function (Pousinha et al., 2017) and on intrinsic excitability (Pousinha et al., 2019). Increased levels of AICD enhance GluN2B-NMDAR contribution, overactivate SK channels, and strongly perturb long-term potentiation (LTP), but spare long-term depression (LTD) in CA1 pyramidal neurons. Partial antagonism of GluN2B-NMDAR rescues LTP in early AD. Oligomeric forms of amyloid beta prevented induction of LTP in hippocampal cultured neurons (Opazo et al., 2018). CaMKII inhibitors KN93, tatCN21, and specific GluN2B-NMDAR antagonist ifenprodil completely rescued Aβ-induced inhibition of LTP by preventing CaMKII overactivation and dendritic spine loss (Opazo et al., 2018). Pousinha, P. A., Mouska, X., Raymond, E. F., Gwizdek, C., Dhib, G., Poupon, G., et al. (2017). Physiological and pathophysiological control of synaptic GluN2B-NMDA receptors by the C-terminal domain of amyloid precursor protein. eLife 6:e25659. doi: 10.7554/eLife.25659 Pousinha, P. A., Mouska, X., Bianchi, D., Temido-Ferreira, M., Raj ao-Saraiva, J., Gomes, R., et al. (2019). The amyloid precursor protein C-terminal domain alters CA1 neuron firing, modifying hippocampus oscillations and impairing spatial memory encoding. Cell Rep. 29, 317–331.e5. doi: 10.1016/j.celrep.2019.08.103 Opazo, P., Viana da Silva, S., Carta, M., Breillat, C., Coultrap, S. J., Grillo-Bosch, D., et al. (2018). CaMKII metaplasticity drives Aβ oligomer-mediated synaptotoxicity. Cell Rep. 23, 3137–3145.
Model Type: Synapse
Region(s) or Organism(s): Hippocampus
Cell Type(s): Hippocampus CA1 pyramidal GLU cell
Currents:
Genes:
Transmitters: Glutamate
Model Concept(s): Synaptic Plasticity
Simulation Environment: NEURON; Python
Implementer(s): Dainauskas, Justinas J
References: