Neurotensin (NT) is a tridecapeptide widely distributed in the CNS including the entorhinal cortex (EC) which is crucial for learning and memory and undergoes the earliest pathological alterations in Alzheimer's Disease (AD). Whereas high density of NT receptors has been detected in the EC, the roles of NT in learning and memory and in AD have not been determined. AD is characterized by progressive deterioration of cognitive performance and afflicts ~5.3 million Americans. The current drugs available for the treatment of AD including the cholinesterase inhibitors and the partial NMDA receptor antagonist memantine only benefit a subset of patients for a limited period. Therefore, identifying and characterizing additional mechanisms through which cognitive deficiency can be improved still represent an important approach for AD therapy. We propose to study the roles and the underlying mechanisms of NT in facilitation of spatial memory in the EC and then test the possibility of using NT receptor agonists for AD therapy in AD mouse model. We have substantial preliminary data demonstrating that NT induced Long-Term Excitation (LTE) of neuronal excitability in the EC. We also demonstrated that microinjection of NT into the EC facilitated spatial learning and memory in Barnes Maze Test. The objective of this project is to determine the involved cellular and molecular mechanisms by testing the hypothesis that NT induces LTE of neuronal excitability and facilitates spatial learning and memory via NTS1/PLC/PKC-dependent inhibition of TREK-2 channels.
Aim 1 will identify mechanisms underlying NT-induced LTE of neuronal excitability in the EC. We will identify the roles of PKC isoforms, PKC phosphorylation sites in TREK-2 channels and PKC- dependent phosphorylation of TREK-2 channels in vivo in NT-mediated LTE in the EC.
Aim 2 will determine the mechanisms whereby NT facilitates spatial learning and memory by testing the hypothesis that NT augments spatial learning and memory via activation of PLC and PKC pathway resulting in inhibition of TREK-2 channels in the EC by using both pharmacological approach and knockout mice.
Aim 3 will identify effects of NT and PD149163, a small molecule NTS1 agonist that can penetrate the blood-brain barrier on spatial learning and memory in APP/PS1 mice, an AD mouse model. We expect to determine the cellular and molecular mechanisms whereby NT facilitates spatial learning and memory and identify a novel approach of using NTS1 agonists for AD therapy in AD mouse model.

Public Health Relevance

Neurotensin (NT) is a 13-amino-acid peptide widely distributed in the CNS including the entorhinal cortex (EC) which is a structure that is crucial fo learning and memory and undergoes the earliest pathological alterations in Alzheimer's Disease (AD). The EC also expresses high density of NT receptors. However, the roles and underlying mechanisms of NT in modulating learning and memory in the EC and the therapeutic potential of NT receptor modulators in AD have not been determined. AD is a common disease in the elderly that is characterized by progressive deterioration of cognitive performance. Whereas the cholinesterase inhibitors and the partial NMDA receptor antagonist memantine are the currently available drugs for the treatment of AD, these drugs provide only minimal benefit to a subset of patients for a limited period. Identifying and characterizing additional mechanisms through which cognitive deficiency can be improved are still a major therapeutic approach for AD. We have substantial preliminary data demonstrating that NT induced Long-Term Excitation (LTE) of neuronal excitability in the EC and microinjection of NT into the EC facilitated spatial learning and memory. The overall objective of this application is to determine the underlying mechanisms and the therapeutic potential of NTS1 agonists for AD by testing the hypothesis that NT induces LTE and facilitates spatial learning and memory by inhibition of TREK-2, a background K+ channel.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
2R01MH082881-06A1
Application #
8575395
Study Section
Neurobiology of Learning and Memory Study Section (LAM)
Program Officer
Nadler, Laurie S
Project Start
2008-07-01
Project End
2018-07-31
Budget Start
2013-08-01
Budget End
2014-04-30
Support Year
6
Fiscal Year
2013
Total Cost
$345,000
Indirect Cost
$95,000
Name
University of North Dakota
Department
Pharmacology
Type
Schools of Medicine
DUNS #
102280781
City
Grand Forks
State
ND
Country
United States
Zip Code
58202
Hu, Binqi; Cilz, Nicholas I; Lei, Saobo (2017) Somatostatin depresses the excitability of subicular bursting cells: Roles of inward rectifier K+ channels, KCNQ channels and Epac. Hippocampus 27:971-984
Cilz, Nicholas I; Lei, Saobo (2017) Histamine facilitates GABAergic transmission in the rat entorhinal cortex: Roles of H1 and H2 receptors, Na+ -permeable cation channels, and inward rectifier K+ channels. Hippocampus 27:613-631
Zhang, Haopeng; Dong, Hailong; Cilz, Nicholas I et al. (2016) Neurotensinergic Excitation of Dentate Gyrus Granule Cells via G?q-Coupled Inhibition of TASK-3 Channels. Cereb Cortex 26:977-90
Zhang, Haopeng; Cilz, Nicholas I; Yang, Chuanxiu et al. (2015) Depression of neuronal excitability and epileptic activities by group II metabotropic glutamate receptors in the medial entorhinal cortex. Hippocampus 25:1299-313
Zhang, Haopeng; Dong, Hailong; Lei, Saobo (2015) Neurotensinergic augmentation of glutamate release at the perforant path-granule cell synapse in rat dentate gyrus: Roles of L-Type Ca²? channels, calmodulin and myosin light-chain kinase. Neuropharmacology 95:252-60
Zhang, Hao-peng; Xiao, Zhaoyang; Cilz, Nicholas I et al. (2014) Bombesin facilitates GABAergic transmission and depresses epileptiform activity in the entorhinal cortex. Hippocampus 24:21-31
Xiao, Zhaoyang; Cilz, Nicholas I; Kurada, Lalitha et al. (2014) Activation of neurotensin receptor 1 facilitates neuronal excitability and spatial learning and memory in the entorhinal cortex: beneficial actions in an Alzheimer's disease model. J Neurosci 34:7027-42
Cilz, Nicholas I; Kurada, Lalitha; Hu, Binqi et al. (2014) Dopaminergic modulation of GABAergic transmission in the entorhinal cortex: concerted roles of ?1 adrenoreceptors, inward rectifier K?, and T-type Ca²? channels. Cereb Cortex 24:3195-208
Kurada, Lalitha; Yang, Chuanxiu; Lei, Saobo (2014) Corticotropin-releasing factor facilitates epileptiform activity in the entorhinal cortex: roles of CRF2 receptors and PKA pathway. PLoS One 9:e88109
Wang, Shouping; Kurada, Lalitha; Cilz, Nicholas I et al. (2013) Adenosinergic depression of glutamatergic transmission in the entorhinal cortex of juvenile rats via reduction of glutamate release probability and the number of releasable vesicles. PLoS One 8:e62185

Showing the most recent 10 out of 20 publications