1,1,3 Tricyano-2-amino-1-propene (Triap) stimulates choline acetyltransferase activity in vitro and in vivo

Abstract

1,1,3 Tricyano-2-amino-1-propene (Triap) is a small molecule that has neurotrophic properties similar to nerve growth factor (NGF). Studies have shown that NGF increases choline acetyltransferase (ChAT) activity, the enzyme responsible for the synthesis of acetylcholine, in several cell lines and in the CNS of adult animals. To investigate whether Triap can cause similar increases in ChAT enzyme activity, we used the PC12 cell line and primary cultures of rat fetal brain tissue to examine Triap's effects. Nanomolar concentrations of Triap produced a 4.2- and 2.1-fold increase in the ChAT activity of PC12 cells and cultured rat fetal brain cells, respectively. This stimulation reached a plateau within 4 days of treatment in the primary fetal brain cultures with the first increases evident within 24 h. In the PC12 cell line, Triap's stimulation of ChAT activity was significantly greater than increases produced by optimal concentrations of NGF. Triap also matched NGF's stimulation of ChAT activity in primary neuronal culture. Triap also potentiated NGF's actions on ChAT activity in the PC12 cell line and in primary fetal neuronal cultures. These increases in enzyme activity correlated with increases in cellular enzyme levels as assessed using immunochemical identification of the ChAT enzyme. We also conducted experiments to determine if Triap also induced these same increases in ChAT activity in adult animals. Ten-day chronic injections of Triap in mice resulted in significant increases in specific ChAT enzyme activity in the cortex and septal-hippocampal area. Similar increases in ChAT enzyme levels were also detected using western blotting techniques. Thus, it appears that Triap increases ChAT activity, similar to NGF, in both cultured cells and in adult animals. Triap's effects on ChAT enzyme activity seem to be mediated primarily through increases in enzyme concentration. These results show that Triap is a neurotrophic agent with potent effects on the cholinergic nervous system and may be useful as a potential therapeutic agent in diseases exhibiting cholinergic deficits.