Reliably regrowing hair is one of those advances that’s proving trickier than you might imagine, but scientists have plenty of leads to follow. Now, researchers from North Carolina State University have identified a particular microRNA molecule that appears to regulate hair regeneration, which could be a new drug target for a shortcut treatment that doesn’t involve growing and administering entire new cells.
Increasingly, research into hair loss has focused on dermal papillae (DP) cells, which sit right at the base of hair follicles, where they support and regulate hair growth. So the thinking goes that replenishing DP cells in people experiencing hair loss could help kickstart regrowth.
The problem with culturing new human cells in the lab is that it’s often done in the two-dimensional environment of a dish, which doesn’t completely reflect their natural habitat in the body. To make more accurate versions, researchers use 3D structures called spheroids.
For the new study, the researchers compared 2D and 3D versions of cultured DP cells, testing how each worked to regenerate hair in mice. A third group of animals received the commercial treatment minoxidil. After a 20-day trial, the team found that the 3D DP cells worked best. By day 15, the mice in this group had regained as much as 90 percent of their original hair coverage.
“The 3D cells in a keratin scaffold performed best, as the spheroid mimics the hair microenvironment and the keratin scaffold acts as an anchor to keep them at the site where they are needed,” says Ke Cheng, lead researcher on the study.
To investigate further, the team also examined why these DP cells worked. The key seemed to be small molecules called microRNAs, which regulate gene expression. These are passed between cells in tiny sacs called exosomes.
By studying microRNA in exosomes from both 2D and 3D DP cells, the team identified one that was particularly promising. Known as miR-218-5p, this molecule plays a key role in promoting the growth of hair follicles. When they increased its levels, hair follicle growth went up, while inhibiting miR-218-5p deactivated them.
With this specific microRNA molecule isolated, the team says it could be a good drug target for future research and hopefully, future treatments. If so, it could be easier than trying to replace the DP cells themselves.
“Cell therapy with the 3D cells could be an effective treatment for baldness, but you have to grow, expand, preserve and inject those cells into the area,” says Cheng. “MiRNAs, on the other hand, can be utilized in small molecule-based drugs. So potentially you could create a cream or lotion that has a similar effect with many fewer problems. Future studies will focus on using just this miRNA to promote hair growth.”
The research was published in the journal Science Advances.
Source: North Carolina State University
