I have rarely discussed hair follicle keratinocytes on this blog. However, a new study published by EpiBiotech CEO Jong-Hyuk Sung in collaboration with researchers from Seoul National University College of Pharmacy has given me the opportunity.
Keratinocytes of the Hair Follicles and Skin
The new December 2024 study (that is not yet available in full) is titled:
“Differential expression of androgen receptor and 5-α reductase isoforms in skin cells“.
A summary of its findings can be read here (h/t “Ben”). Interestingly, an older 2014 study that I came across while writing this post is titled: “Differential expression of 5-alpha reductase isozymes in the prostate and its clinical implications.”
The researchers used single-cell RNA sequencing technology to identify the expression sites of androgen receptors and 5-α reductase in human and mouse skin cells. They analyzed all three isozymes of 5α-reductase (encoded by the genes SRD5A1, SRD5A2, and SRD5A3). Past research has found that SRD5A2 is not expressed in the skin and hair follicles.
The study confirms that dihydrotestosterone (DHT) biosynthesis (the cause of pattern hair loss) is produced in the keratinocytes of skin and hair follicles. And not in dermal papilla cells (or dermal sheath cup cells) which are the main focus of hair multiplication research.
EpiBiotech CEO Seong-Hyeok Sung said:
“This study suggests a new mechanism for androgenetic alopecia treatment and opens up the possibility of a new approach targeting hair follicle keratinocytes, moving away from the existing dermal papilla cell-centered treatment method.”
Considering the diverse range of hair loss treatments and research that Epibiotech is focusing on (in a rapid manner), I am reluctant to put too much stock into their findings as yet.
Past Discussions of Keratinocytes on this Blog
When I started writing this post, I did a search of the past mentions of keratinocytes on this blog. Lo and behold, I found something unusual right off the bat.
- In my 2020 update to an old post on research from Dr. Jeff Bernaskie’s team from the University of Calgary, I came across the following text from this source:
“For decades, researchers studying aging and hair loss have focused on keratinocytes, the cells that make up the bulk of the hair follicle and eventually give rise to the hair fibre. But a study from the University of Calgary Faculty of Veterinary Medicine (UCVM) has found that it’s actually a small population of specialized cells within the hair follicle called fibroblasts, and the dermal stem cells that maintain them, that may cause hair loss.”
This says the opposite of what Jong-Hyuk Sung said in regards to the lack of importance given to keratinocytes in the past. My personal feeling is that Mr. Sung is correct and the importance given to keratinocytes has been less than that given to dermal stem cells. However, Dr. Bernaskie is a highly respected researcher, and perhaps the above pasted statement is not a direct quote from him.
- In my 2017 interview with Stemson Therapeutics co-founder Dr. Alexey Terskikh, he said the following:
“Then DP cells will be mixed with keratinocytes within a specialized matrix scaffold and transplanted back into the same patient’s skin.”
- When discussing fibroblast growth factors in past posts, I have noted that FGF7 (also called keratinocyte growth factor, or KGF) is required for hair growth. The much discussed and maligned Histogen (no longer active) was developing a Hair Stimulating Complex that included KGF as a key ingredient.
