Abstract
The complex and heterogeneous genetic architecture of neuropsychiatric illnesses compels us to look beyond individual risk genes for therapeutic strategies and target the interactive dynamics and convergence of their protein products. A mechanistic substrate for convergence of synaptic neuropsychiatric risk genes are protein-protein interactions (PPIs) in the NMDAR complex. NMDAR hypofunction in schizophrenia is associated with hypoactivity of Src kinase, resulting from convergent alterations in PPIs of Src with its partners. Of these, the association of Src with PSD-95, which inhibits the activity of this kinase in the NMDAR complex, is known to be increased in schizophrenia. Here, we devised a strategy to suppress the inhibition of Src by PSD-95 by employing a cell penetrating and Src activating PSD-95 inhibitory peptide (TAT-SAPIP). TAT-SAPIP enhanced synaptic NMDAR currents in Src+/- and Sdy-/- mice manifesting NMDAR hypofunction phenotypes. Chronic ICV injection of TAT-SAPIP rescued cognitive deficits in trace fear conditioning in Src +/- mice. Moreover, TAT-SAPIP enhanced Src activity in synaptoneurosomes derived from dorsolateral prefrontal cortex of 14 subjects including patients and healthy subjects. We propose blockade of the Src-PSD-95 interaction as a proof of concept for the use of interfering peptides as a therapeutic strategy to reverse NMDAR hypofunction in schizophrenia and other illnesses.
Authors
Robert E. Featherstone, Hongbin Li, Ameet S. Sengar, Karin E. Borgmann-Winter, Olya Melnychenko, Lindsey M. Crown, Ray L. Gifford, Felix Amirfathi, Anamika Banerjee, AiVi Tran, Krishna Parekh, Margaret Heller, Wenyu Zhang, Robert J. Gallop, Adam D. Marc, Pragya Komal, Michael W. Salter, Steven J. Siegel, Chang-Gyu Hahn
