Gaku Tsuji

Filaggrin (FLG) mutation is a well-confirmed genetic aberration in atopic dermatitis (AD). Genome-wide association studies on AD have revealed other susceptibility genes, for example, Ovo-like 1 (OVOL1). Nonetheless, the relation between FLG and OVOL1 is unclear. Because aryl hydrocarbon receptor (AHR; a ligand-activated transcription factor), plays a role in FLG expression in keratinocytes, we hypothesized that AHR regulates FLG expression via OVOL1. To demonstrate this mechanism, we analyzed F

Psoriasis is a systemic inflammatory disease significantly associated with comorbidities including type 2 diabetes mellitus (T2DM). Metformin is utilized as a first-line agent for treating T2DM. Although metformin reportedly inhibits mature IL-1β secretion via NLRP3 inflammasome in macrophages of T2DM patients, it remains unclear whether it affects skin inflammation in psoriasis. To test this, we analysed normal human epidermal keratinocytes (NHEKs), a major skin component, stimulated with the k

Severe pruritus is a characteristic feature of atopic dermatitis (AD) and is closely related to its activity. Recent studies have shown that IL-31 is a key determinant of pruritus in AD. Anti-IL-31 receptor alpha (IL-31RA) antibody treatment has also been reported to improve pruritus clinically, subsequently contributing to the attenuation of AD disease activity. Therefore, IL-31 has been thought to be an important cytokine for regulating pruritus and AD disease activity; however, how IL-31 is i

Skin barrier dysfunction, including reduced filaggrin (FLG) and loricrin (LOR) expression, plays a critical role in atopic dermatitis (AD) development. Since aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, mediates keratinocyte differentiation, it is a potential target for AD treatment. Recently, clinical studies have shown that tapinarof, an AHR modulator, attenuated the development of AD. To examine the molecular mechanism involved in this, we analyzed tapinarof-treat

Atopic dermatitis (AD) is a common inflammatory skin disease. Recent studies have revealed the involvement of T helper (Th)2 cytokines including Interleukin 4 (IL-4) in the pathogenesis of AD. Since epidermal Langerhans cells (LCs) and dermal myeloid dendritic cells (DCs) produce CCL17 and CCL22 that chemoattract Th2 cells, interfering with CCL17 and CCL22 production from LCs and dermal myeloid DCs may be beneficial in the treatment of AD. To investigate this, we stimulated murine bone marrow-de

These findings suggest that the endogenous photo-product FICZ may be a key chromophore that involves in photo-aging. Downregulation of FICZ signaling is thus a potential strategy to protect against photo-aging.