Maksim Plikus was still an undergraduate when he first became fascinated by the study of hair biology. His lab supervisor asked him to dissect a rat whisker, and to recombine parts of it to see if it could form a new hair follicle.

“I squished it to bits, and it looked like soup,” said Plikus, who is now a Professor of Developmental and Cell Biology at the University of California, Irvine (UCI). “My supervisor told me, ‘You’re probably not ready.’ Instead of giving up, however, I would ask to come on the weekends and try it again and again, and I finally got the hang of it. Once you manipulate something as small as a hair follicle under the microscope, you realize how exquisitely complex such miniature structures are, and that captivated me.”

Plikus always had an inclination towards science. As a kid, he dreamed of exploring the oceans like Jacques Cousteau or parlaying his collection of colorful beetles into a career in entomology. When he was 14, his parents indulged his scientific curiosity by buying him a microscope, which led to a summer watching and drawing various protozoans that inhabited his grandparents’ not-so-clean swimming pool.

After developing his fascination for hair follicles, he landed a gig as an intern at a hair transplantation clinic, but quickly realized he missed doing experiments.

“I then reached out to my future advisor, who is Dr. Cheng-Ming Chuong at USC and told him I would be happy with any lab position, even to wash glassware as long as I could still participate in experiments.’ And he said, ‘Why don’t you apply for the PhD program?’ So then I applied, and I got in and started in his lab in 2001. Dr. Chuong’s fascination with diverse animal forms in the natural world had a fundamental influence on my own view on science as I matured. In his lab, you really start looking at things through the prism of evolution.”

As a PhD student in Pathology, Plikus used transgenic mice to study the molecular basis of hair development and regeneration. He then received a California Institute for Regenerative Medicine (CIRM) fellowship to continue his research in Dr. Chuong’s lab as a postdoc.

“CIRM funding that supported me during my first postdoc was truly essential,” he said. “It supported several new pilot experiments, which eventually ended up producing a couple of really important papers, including one in Science that, in turn, was essential for me to apply for the faculty job. So, in that sense, for my career, CIRM support was vital.”

Plikus then pursued a second postdoc studying hair in the context of wound healing in Dr. George Cotsarelis’ lab at the University of Pennsylvania in Philadelphia. Then in 2012, he was drawn back to California, where he started his faculty position at the CIRM-funded stem cell research center at UCI. In his newly minted lab, Plikus gravitated towards high-risk projects that easily could have failed, but fortunately succeeded.

“When I started, I had a couple of totally new ideas that were outside of my comfort zone,” he said. “I was really naive about the science behind them, but I quickly learned ‘on the job.’ Some years later, these ideas ended up being really intriguing discoveries that shaped the lab and defined the directions that the lab is taking now. And along the way, they produced all kinds of benefits, including funding.”

Through one of these projects, Plikus explored why some pigmented skin moles are hairy.

“Our inquiry into this question uncovered some really fascinating biology that we ended up publishing recently in a Nature paper,” he said. “We revealed an unconventional role for senescent cells, which is another scientific term for aged cells that tend to linger in tissues.”

Skin moles contain clusters of senescent cells, traditionally thought to be harmful contributors to tissues, causing their decline. However, Plikus found that senescent cells secrete molecules that signal to stem cells within local hair follicles, stimulating them to “regenerate excessively, like there is no tomorrow,” he said.

“Through just being curious about these unsightly hairy moles, we actually discovered not only new molecules with clinical potential for hair loss, but also unconventional regeneration-inducing properties of aged cells. Our findings showed that senescent cells are not always categorically bad for tissues. As it turns out, their effects are very context dependent.”

Thanks to CIRM’s strategic investments and support, Plikus has not only advanced the understanding of biology, but also driven innovation that will ultimately benefit patients in California and around the world.

Plikus’ passion has also contributed to UCI’s growing prominence in the field of hair and skin biology.

“There was already a nascent cluster of high-quality skin biologists that I joined on day one,” he said. “And over the years, we’ve built that up by recruiting even more faculty whose labs primarily do skin biology. UCI now has an official Skin Biology Center and our own training grants. And to have this community of like-minded people getting fascinated by hair to the same degree as I do on a daily basis is really critical.”