Human serotonin neurons grown in petri dish

For the first time ever, a team of Chinese and American scientists have developed serotonin-producing neurons from human fibroblasts, the cells that transform into connective tissue in the body.

Serotonin is a crucial neurotransmitter linked to mood and mental issues like depression. The team said their study, published in the journal Molecular Psychology, not only helps with serotonin research – it will also assist other research teams trying to grow various cell types from fibroblasts.

“Our work demonstrates that the precious serotonin neurons hidden deep inside the human brain can now be created in a petri dish,” study author Jian Feng, a biophysics professor at the University at Buffalo, said in a news release.

The new study expands on previous research showing that human fibroblasts can be modified to neurons, using particular transcription factors that attach to genes, switching them on or off. This was the first direct conversion of fibroblasts into “induced serotonergic neurons,” which act like serotonin neurons in the human brain.

“We know the cells were converted to serotonergic neurons because they express proteins that are only found in neurons that produce serotonin,” Feng explained. “They are electrophysiologically active and demonstrate both the controlled release and the selective uptake of serotonin.”

To induce the development of these specialized neurons, the researchers supplied four genes that control the progression of serotonin neurons. Feng noted that the development will allow researchers to grow serotonin neurons for a specific patient from his or her cells.

Patient-specific serotonin cells will be extremely useful

“These patient-specific serotonin neurons will be very useful to the discovery of new drugs for diseases ranging from depression and anxiety to obsessive-compulsive disorder and many others,” Feng said. “They will not only allow researchers to study why certain individuals develop a disease but also to find out what can be done to treat it.”

In addition to creating serotonin neurons, Feng said the same technology should be able to generate other new cells and tissues.

“This research shows that it is possible to convert one type of cell into other types that have been difficult to access, such as neurons or heart cells,” he said. “All we need to do is find out the combination of transcription factors that is necessary. Sooner or later, we will find out what those combinations are so that we can regenerate cells and eventually tissues that will mimic the real cells and tissues in the body.”

(Image credit: Jian Feng/University at Buffalo)