A Model System for A Devastating Childhood Disease

A Japanese research team from Fukuoka, Japan, specifically from the Department of Pediatrics at the University of Fukuoka, Japan, have used induced pluripotent stem cell technology to make neurons from human patients who suffer from a rare, devastating condition known as Dravet syndrome as a model system.

Dravet syndrome (DS) causes difficult to control seizures within the first year or two of life and later causes cognitive deficits and autistic traits. Dravet’s syndrome is caused by genetic alterations in the SCN1A gene, which encodes the α-subunit of the voltage-gated sodium channel.

DS is very rare – 1/30,000 children, but the mutation is typically not inherited from either parent, but occurs spontaneously in the baby’s cells during development. The best model systems to date are genetically engineered mice, but the differences between human and mouse brains limits the usefulness of this model system.

To make a better model system, workers from the laboratory of Shinichi Hirose took skin biopsy samples from a DS patient, and converted those skin cells into induced pluripotent stem cells (iPSCs), which were then differentiated into neurons. In particular, the neurons that malfunction in DS patients are GABAminergic neurons, and by differentiating DS iPSCs into GABAminergic neurons, Hirose’s laboratory made a model system for DS patients that could be grown in a laboratory culture dish.

Hirose explained their results this way: “From research in mice we believed that SCN1A mutations affect GABAminergic neurons in the forebrain from signaling properly. From the human neurons we also found that GABAminergic neurons were affected by DS, especially during intense stimulation. These patient-specific cell provide an unparalleled insight into the mechanism behind DS and a unique platform for drug development.”

Perhaps such experiments could eventually lead to regenerative treatments for DS patients as well.