二芳基恶唑烷酮通过调节人角质形成细胞中的富含脯氨酸的蛋白来抑制 PDE4，从而调节丝聚蛋白和兜甲蛋白的表达。

PDE4 inhibition by difamilast regulates filaggrin and loricrin expression via keratinocyte proline-rich protein in human keratinocytes.

机构信息

Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan; Research and Clinical Center for Yusho and Dioxin, Kyushu University Hospital, Fukuoka, Japan.

出版信息

J Dermatol Sci. 2023 May;110(2):61-68. doi: 10.1016/j.jdermsci.2023.04.007. Epub 2023 Apr 28.

DOI:10.1016/j.jdermsci.2023.04.007

PMID:37156706

Abstract

BACKGROUND

Difamilast, a topical phosphodiesterase 4 (PDE4) inhibitor, has been shown to be effective for treating atopic dermatitis (AD), but the molecular mechanism involved is unclear. Since skin barrier dysfunction including reduced expression of filaggrin (FLG) and loricrin (LOR) contributes to AD development, difamilast treatment may be able to improve this dysfunction. PDE4 inhibition increases transcriptional activity of cAMP-responsive element binding protein (CREB). Therefore, we hypothesized that difamilast may affect FLG and LOR expression via CREB in human keratinocytes.

OBJECTIVE

To elucidate the mechanism by which difamilast regulates FLG and LOR expression via CREB in human keratinocytes.

METHODS

We analyzed normal human epidermal keratinocytes (NHEKs) treated with difamilast.

RESULTS

We observed increases of intracellular cAMP levels and CREB phosphorylation in difamilast (5 μM)-treated NHEKs. Next, we found that difamilast treatment increased mRNA and protein levels of FLG and LOR in NHEKs. Since reduced expression of keratinocyte proline-rich protein (KPRP) is reported to be involved in skin barrier dysfunction in AD, we examined KPRP expression in difamilast-treated NHEKs. We found that difamilast treatment increased mRNA and protein levels of KPRP in NHEKs. Furthermore, KPRP knockdown using siRNA transfection abolished the upregulation of FLG and LOR in difamilast-treated NHEKs. Finally, CREB knockdown canceled the upregulation of FLG, LOR, and KPRP in difamilast-treated NHEKs, indicating that PDE4 inhibition by difamilast treatment positively regulates FLG and LOR expression via the CREB-KPRP axis in NHEKs.

CONCLUSION

These findings may provide further guidance for therapeutic strategies in the treatment of AD using difamilast.

摘要

背景

二氟米特是一种局部磷酸二酯酶 4（PDE4）抑制剂，已被证明对治疗特应性皮炎（AD）有效，但涉及的分子机制尚不清楚。由于皮肤屏障功能障碍包括丝聚合蛋白（FLG）和兜甲蛋白（LOR）表达减少导致 AD 的发展，二氟米特治疗可能能够改善这种功能障碍。PDE4 抑制增加环磷腺苷反应元件结合蛋白（CREB）的转录活性。因此，我们假设二氟米特可能通过人角质形成细胞中的 CREB 影响 FLG 和 LOR 的表达。

目的

阐明二氟米特通过 CREB 调节人角质形成细胞中 FLG 和 LOR 表达的机制。

方法

我们分析了用二氟米特处理的正常人类表皮角质形成细胞（NHEKs）。

结果

我们观察到二氟米特（5 μM）处理的 NHEKs 细胞内环腺苷酸（cAMP）水平和 CREB 磷酸化增加。接下来，我们发现在 NHEKs 中二氟米特处理增加了 FLG 和 LOR 的 mRNA 和蛋白水平。由于有报道称 AD 中角质形成细胞富含脯氨酸蛋白（KPRP）的表达减少与皮肤屏障功能障碍有关，我们检查了二氟米特处理的 NHEKs 中的 KPRP 表达。我们发现二氟米特处理增加了 NHEKs 中的 KPRP 的 mRNA 和蛋白水平。此外，使用 siRNA 转染敲低 KPRP 消除了二氟米特处理的 NHEKs 中 FLG 和 LOR 的上调。最后，CREB 敲低取消了二氟米特处理的 NHEKs 中 FLG、LOR 和 KPRP 的上调，表明二氟米特通过 CREB-KPRP 轴积极调节 NHEKs 中的 FLG 和 LOR 表达。