A TrkB and TrkC partial agonist restores deficits in synaptic function and promotes activity-dependent synaptic and microglial transcriptomic changes in a late-stage Alzheimer's mouse model.

Amira Latif-Hernandez,Tao Yang,Robert Raymond-Butler,Patricia Moran Losada,Patricia Moran Losada,Patricia Moran Losada,Patricia Moran Losada,Paras S Minhas,Halle White,Kevin C Tran,Harry Liu,Danielle A Simmons,Vanessa Langness,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Katrin I Andreasson,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Tony Wyss-Coray,Frank M Longo,Frank M Longo,Frank M Longo,Frank M Longo

doi:10.1002/alz.13857

Abstract

Tropomyosin related kinase B (TrkB) and C (TrkC) receptor signaling promotes synaptic plasticity and interacts with pathways affected by amyloid beta (Aβ) toxicity. Upregulating TrkB/C signaling could reduce Alzheimer's disease (AD)-related degenerative signaling, memory loss, and synaptic dysfunction. PTX-BD10-2 (BD10-2), a small molecule TrkB/C receptor partial agonist, was orally administered to aged London/Swedish-APP mutant mice (APPL/S) and wild-type controls. Effects on memory and hippocampal long-term potentiation (LTP) were assessed using electrophysiology, behavioral studies, immunoblotting, immunofluorescence staining, and RNA sequencing. In APPL/S mice, BD10-2 treatment improved memory and LTP deficits. This was accompanied by normalized phosphorylation of protein kinase B (Akt), calcium-calmodulin-dependent kinase II (CaMKII), and AMPA-type glutamate receptors containing the subunit GluA1; enhanced activity-dependent recruitment of synaptic proteins; and increased excitatory synapse number. BD10-2 also had potentially favorable effects on LTP-dependent complement pathway and synaptic gene transcription. BD10-2 prevented APPL/S/Aβ-associated memory and LTP deficits, reduced abnormalities in synapse-related signaling and activity-dependent transcription of synaptic genes, and bolstered transcriptional changes associated with microglial immune response. Small molecule modulation of tropomyosin related kinase B (TrkB) and C (TrkC) restores long-term potentiation (LTP) and behavior in an Alzheimer's disease (AD) model. Modulation of TrkB and TrkC regulates synaptic activity-dependent transcription. TrkB and TrkC receptors are candidate targets for translational therapeutics. Electrophysiology combined with transcriptomics elucidates synaptic restoration. LTP identifies neuron and microglia AD-relevant human-mouse co-expression modules.

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