Referenced in: none

Automatically associated channels: TRP , TRPC , TRPC3 , TRPC6 , TRPC7

Title: Screening of Transient Receptor Potential Canonical Channel Activators Identifies Novel Neurotrophic Piperazine Compounds.

Authors: Seishiro Sawamura, Masahiko Hatano, Yoshinori Takada, Kyosuke Hino, Tetsuya Kawamura, Jun Tanikawa, Hiroshi Nakagawa, Hideharu Hase, Akito Nakao, Mitsuru Hirano, Rachapun Rotrattanadumrong, Shigeki Kiyonaka, Masayuki X Mori, Motohiro Nishida, Yaopeng Hu, Ryuji Inoue, Ryu Nagata, Yasuo Mori

Journal, date & volume: Mol. Pharmacol., 2016 Mar , 89, 348-63

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/26733543

Abstract
Transient receptor potential canonical (TRPC) proteins form Ca(2+)-permeable cation channels activated upon stimulation of metabotropic receptors coupled to phospholipase C. Among the TRPC subfamily, TRPC3 and TRPC6 channels activated directly by diacylglycerol (DAG) play important roles in brain-derived neurotrophic factor (BDNF) signaling, promoting neuronal development and survival. In various disease models, BDNF restores neurologic deficits, but its therapeutic potential is limited by its poor pharmacokinetic profile. Elucidation of a framework for designing small molecules, which elicit BDNF-like activity via TRPC3 and TRPC6, establishes a solid basis to overcome this limitation. We discovered, through library screening, a group of piperazine-derived compounds that activate DAG-activated TRPC3/TRPC6/TRPC7 channels. The compounds [4-(5-chloro-2-methylphenyl)piperazin-1-yl](3-fluorophenyl)methanone (PPZ1) and 2-[4-(2,3-dimethylphenyl)piperazin-1-yl]-N-(2-ethoxyphenyl)acetamide (PPZ2) activated, in a dose-dependent manner, recombinant TRPC3/TRPC6/TRPC7 channels, but not other TRPCs, in human embryonic kidney cells. PPZ2 activated native TRPC6-like channels in smooth muscle cells isolated from rabbit portal vein. Also, PPZ2 evoked cation currents and Ca(2+) influx in rat cultured central neurons. Strikingly, both compounds induced BDNF-like neurite growth and neuroprotection, which were abolished by a knockdown or inhibition of TRPC3/TRPC6/TRPC7 in cultured neurons. Inhibitors of Ca(2+) signaling pathways, except calcineurin, impaired neurite outgrowth promotion induced by PPZ compounds. PPZ2 increased activation of the Ca(2+)-dependent transcription factor, cAMP response element-binding protein. These findings suggest that Ca(2+) signaling mediated by activation of DAG-activated TRPC channels underlies neurotrophic effects of PPZ compounds. Thus, piperazine-derived activators of DAG-activated TRPC channels provide important insights for future development of a new class of synthetic neurotrophic drugs.