Osteopontin and CD44 molecules may play a crucial role in stimulating hair growth in skin moles or nevi, even in the presence of many senescent (old) skin cells, according to a study published in the journal Nature.
In the past, some researchers believed that senescent cells are usually associated with aging, which is bad for the regeneration of cells. However, a team of healthcare professionals and academics from the U.S., China, France, Germany, Korea, Japan, and Taiwan conducted a study that contradicts this belief.
Dr. Xiaojie Wang of the University of California, Irving, led this study. According to the researchers, melanocytic skin nevi (a typical pigmented skin lesion) often displays excessive hair growth, which may suggest hyperactivity of hair stem cells. They then used genetic mouse models of nevi to see if it would replicate enhanced hair growth.
The researchers observed that nevus melanocytes release signaling factors like osteopontin (the main factor released), and this factor is “ both necessary and sufficient to induce hair growth.” When the researcher injected osteopontin or its genetic overexpression into mice, they observed robust hair growth. The researchers believe that this strong hair growth is due to molecular interaction between osteopontin and CD44 (a receptor of osteopontin on hair cells), which leads to the activation of hair stem cells.
In addition, the researchers also noticed that deleting osteopontin or CD44 reversed the enhanced hair growth induced by the nevus melanocytes.
“We found that senescent pigment cells produce large quantities of a specific signaling molecule called osteopontin, which causes normally dormant and diminutive hair follicles to activate their stem cells for robust growth of long and thick hairs,” said lead corresponding author Dr. Maksim Plikus. “Senescent cells are typically viewed as detrimental to regeneration and are thought to drive the aging process as they accumulate in tissues throughout the body, but our research clearly shows that cellular senescence has a positive side to it.”
The researchers believe this finding will open new avenues for molecular therapy for androgenetic alopecia, a common form of hair loss in both women and men.
“In addition to osteopontin and CD44, we’re looking deeper into other molecules present in hairy skin nevi and their ability to induce hair growth. It’s likely that our continued research will identify additional potent activators,” Dr. Plikus said.
Journal Source: NATURE