TITLE:
Baicalein and Salvia officinalis Extract Upregulate Transglutaminase 1 mRNA Expression via the Activation of Transient Receptor Potential Channel V4
AUTHORS:
Akihiro Aioi, Ryuta Muromoto, Tadashi Matsuda
KEYWORDS:
Transient Receptor Potential Channels, Transglutaminase 1, Salvia officinalis, Skin Homeostasis
JOURNAL NAME:
Journal of Cosmetics, Dermatological Sciences and Applications,
Vol.12 No.1,
March
2,
2022
ABSTRACT: Background: It is important to maintain skin homeostasis for cosmetic and medical reasons. Many ceramide-related ingredients and cosmetics have been developed to improve the skin barrier function and skin hydration. Similar to extracellular lipids, the cornified envelope, which is a structure formed beneath the plasma membrane, contributes to the skin barrier function as a scaffold for extracellular lipids. Therefore, in this study, we focused on transglutaminase 1 (TGM1) which is the key enzyme for formation of the cornified envelope Objective: The objectives of this study were to identify compounds that could upregulate the expression of TGM1 and evaluate their underlying action mechanisms. Methods: Expression of the transient receptor potential channel vanilloid subfamily member 4 (TRPV4) at the mRNA and protein levels was estimated by PCR and western blotting. Effects of baicalein and Salvia officinalis (SO) extract on TGM1 mRNA expression were measured by PCR. The involvement of TRPV4 in TGM1 mRNA expression was evaluated by the inhibition and silencing of TRPV4. Results: TRPV4 was expressed in both basal cell-like HaCaT cells and suprabasal cell-like HaCaT cells. Baicalein and SO extract upregulated TGM1 mRNA expression in basal cell-like HaCaT cells. However, inhibition and silencing of TRPV4 abrogated the effects of baicalein and SO extract. Conclusion: Baicalein and SO extract upregulated the expression of TGM1 mRNA via the activation of TRPV4, suggesting that it may improve the skin barrier function by enhancing cornified envelope formation.