The First Serotonin Neurons Created From Stem Cells

Human serotonin-producing neurons, generated from induced pluripotent stem cells. Credit: Jianfeng Lu and Su-Chun Zhang, University of Wisconsin-Madison

As the list of different cell types created from stem cells grows, we can now tick serotonin neurons off the list too. 

Serotonin is an absolutely essential neurotransmitter that controls a massive range of functions from emotion to breathing. Defects in serotonin regulation of production can therefore have considerable side effects, and serotonin dysregulation is implicated in depression and anxiety. 

"Serotonin essentially modulates every aspect of brain function, including movement"

So how do you make a serotonin neuron?

Serotonin neurons emerge before birth, so in order to coax stem cells into morphing into them, researchers attempted to resurrect the chemical environment of a developing brain. This is a complicated task.

"Here, we had to instruct the stem cells to develop into one specific fate, using a custom-designed sequence of molecules at exact concentrations. That's especially difficult if you consider that the conditions needed to make serotonin neurons are scarce, existing in one small location in the brain during development"

Despite the challenge, the scientists were able to produce apparent serotonin neurons from both adult derived stem cells and embryonic ones. These responded to electrical stimulation and importantly began releasing serotonin. To test them further, the team administered FDA approved drugs that regulate the serotonin pathway and confirmed their identity. 

"It was not exactly trial and error; we have some rules to follow, but we had to refine it little by little to work out—one chemical at a time—the concentration and timing, and then check and recheck the results. That's why it took time"

The ability to produce these cells is great news for drug testing, but it also has therapeutic potential in treating crippling mental disorders like depression. 

Read more at MedicalXpress