Depression is a common yet serious disease that affects more than 264 million people worldwide.  It may cause the patients to suffer greatly and harm their performances at work, at school, and in families. Severe symptoms may even lead to suicide. It has been accepted that serotonin deficiency is the major cause of depression, and efforts have been made to improve this situation. Yet patients often feel pressure and refuse to take antidepressants due to social stigmas .
Our project, Tea-HEE, focuses on a novel way to solve this problem. We engineered E. coli Nissle 1917 (an FDA approved probiotic) and plan to place it in patients’ intestine. It will respond to PCA, a tea metabolite derived from tea intake, and then produce 5-HTP, the precursor of serotonin that has multiple advantages for serotonin synthesis. Therefore, by ingesting tea, a common beverage, patients can get an ample supply of 5-HTP in their intestine and hence an ample supply of serotonin in their brain to fight depression without pressure.
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