Opsins and Cryptochrome Photoreceptors Mediate Blue Light Stimulatory Effect on Hair Growth

The document reports on a study that investigated the role of photoreceptors in mediating the effects of blue light on hair growth. The study found that 453 nm blue light at a low radiant exposure of 3.2 J/cm^2 has a positive effect on hair growth by prolonging the anagen phase in hair follicles ex vivo. In vitro experiments with primary outer root sheath (ORS) cells showed that siRNA-mediated inhibition of Cryptochrome 1 (CRY1) or Opsin 3 (OPN3) resulted in reduced cell proliferation. Transcriptomic analysis revealed that knocking down CRY1 or OPN3 altered the expression of genes involved in proliferation and apoptosis. Treatment with blue light stimulated CRY1 protein synthesis and significantly promoted metabolic activity and proliferation of ORS cells, an effect that was negated by OPN3 knockdown. These findings suggest that blue light can stimulate hair growth through interactions with CRY1 and OPN3 photoreceptors.