Takeshi Fujimori’s scientific contributions

In recent years, hair damage by sunlight and chemical treatment such as perming and bleaching has become a consumer concern. It is important to understand the effect of sunlight and chemical treatment on hair microstructure to develop the technology for protection and repair of hair. Our previous study demonstrated that a differential phase contrast scanning X-ray microscopy was a useful nondestructive analysis method to observe internal hair structure with high-resolution. In this study, hair samples with three different chemical treatment (normal, perming and bleaching) and additional irradiation by artificial sunlight were observed with a scanning X-ray microscopic tomography system using a synchrotron radiation light source in order to understand the damaging effect of both sunlight and chemical treatment on hair. The porosity rate in the cortex is higher in the permed hair than normal hair and void distribution in the cross section of permed hair is localized. The porosity rate in the cortex of permed hair is decreased by additional irradiation. The porosity rate of bleached hair is the same as that of normal hair and isn't changed by the irradiation. These results suggest that hair microstructural change in the cortex by sunlight is affected by the prior chemical treatments, and development of varied protection and repair technology depending on the prior treatment situation is needed.

The human hair shaft is covered with multiple scale-like cuticular layers. During the terminal differentiation stage of immature cuticular cells within the hair follicle, cysteine-rich calcium binding S100A3 protein is predominantly translated, and its arginine residues are converted to citrullines by peptidylarginine deiminases (PADI). In this study, we found several naturally occurring compounds (e.g., hinokitiol, escletin, and quercetin) elevate S100A3 citrullination in a human colorectal adenocarcinoma cell line (SW480). Selected compounds similarly promoted cuticular differentiation within isolated human hair follicles. Their promotive activities correlated with the previously reported inhibitory activities of arachidonate 12-lipoxygenase (ALOX12) in vitro. Microarray analysis revealed that ALOX12 inhibitor remarkably up-regulated heparin-binding epidermal growth factor-like growth factor (HBEGF). ALOX12 inhibitor and recombinant HBEGF similarly regulated expression of PADI genes in SW480 cells. In isolated hair follicles, arachidonic acid strongly promoted S100A3 citrullination along with elevation of HBEGF. These results suggest that ALOX12 inhibition efficiently triggers hair cuticle maturation by modulating arachidonate metabolism in concert with HBEGF.