The Characterization of Eicosanoyl-5-hydroxytriptamide (EHT) Synthase in Rat Intestine

Abstract

Neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease (PD) are characterized by progressive neuronal dysfunction and death caused by toxicity and abnormal aggregations of hyperphosphorylated proteins in the brain. Decreased activity of an important protein phosphatase called protein phosphatase 2A (PP2A) in the brain leads to neuronal abnormalities associated with hyperphosphorylated proteins seen in neurodegenerative diseases. A compound found in coffee called eicosanoyl-5-hydroxytryptamide (EHT) has been shown to provide neuroprotective effects by mediating PP2A function. Based on preliminary results and research suggesting that EHT can be endogenously formed, I proposed that EHT is synthesized enzymatically in rat intestine via EHT synthase. The activity of EHT synthase in rat intestine was assessed using a novel enzyme activity assay. EHT production was quantified using high-performance liquid chromatography (HPLC) and liquid chromatography mass spectrometry (LC-MS). In rat intestinal membrane tissue, the activity of EHT production is dependent on the presence of eicosanoyl-CoA (E-CoA) and serotonin (5-HT) and is linear with respect to time. Further, EHT production is preliminarily dependent on the concentration of eicoasnoyl-CoA, but not on the concentration of serotonin or on enzyme concentration. These results suggested the presence of an inhibitor. Bioinformatics analysis showed that EHT synthase might belong to a pre-existing enzyme class called the ceramide synthases (CerS) or another TLC- domain containing enzyme. Future research includes verifying the identity of the enzyme and elucidating its specific role in the body. This discovery could be useful for developing novel pharmaceuticals for treating neurodegeneration.