A team of researchers is revealing the secrets of a simpler way to generate the sensory cells of the inner ear.
Their approach uses direct reprogramming to produce sensory cells known as "hair cells," due to their hair-like protrusions that sense sound waves.
Led by scientists from the USC Stem Cell laboratories of Neil Segil and Justin Ichida, the results of study were published in the journal eLife.
The scientists successfully reprogrammed three different types of mouse cells to become 'induced hair cell-like cells, or iHCs.
The first two types were embryonic and adult versions of connective tissue cells, known as fibroblasts.
The third was a different type of inner ear cell, known as a supporting cell.
To achieve reprogramming, the scientists exposed fibroblasts and supporting cells to a cocktail of four transcription factors, which are molecules that help convey the instructions encoded in DNA.
The scientists identified this cocktail by testing various combinations of 16 transcription factors that were highly active in the hair cells of newborn mice.
The resulting iHCs resembled naturally occurring hair cells in terms of their structure, electrophysiology, and genetic activity.
The iHCs also possessed several other distinct characteristics of hair cells, including vulnerability to an antibiotic known to cause hearing loss.
IHCs have the potential to accelerate hearing loss research in at least two important ways, according to Ichida, who is the John Douglas French Alzheimer's Foundation Associate Professor of Stem Cell Biology and Regenerative Medicine at USC, and the other corresponding author of the study.