State Key Laboratory of Natural Medicines and Department of TCM Pharmacology, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, China.
Institute of Dermatology, Chinese Academy of Medical Sciences & Peking Union Medical College, Nanjing, China.
Br J Pharmacol. 2022 Oct;179(20):4792-4808. doi: 10.1111/bph.15913. Epub 2022 Jul 21.
Atopic dermatitis (AD) is one of the most common chronic inflammatory cutaneous diseases with unmet clinical needs. As a common ingredient found in several medicinal herbs with efficacy on cutaneous inflammatory diseases, Scutellarein (Scu) has been shown to possess anti-inflammatory and anti-proliferative activities. We aimed to evaluate the therapeutic efficacy of Scu against AD and its underlying molecular mechanism.
Efficacy of Scu on AD was evaluated in 2,4-dinitrofluorobenzene (DNFB) and carvacrol-induced dermatitis mouse models. Cytokine mRNA and serum IgE levels were examined using qPCR and ELISA, respectively. Voltage clamp recordings were used to measure currents mediated by transient receptor potential (TRP) channels. In silico docking, site-direct mutagenesis, and covalent modification were used to explore the binding pocket of Scu on TRPV3.
Subcutaneous administration of Scu efficaciously suppresses DNFB and carvacrol-induced pruritus, epidermal hyperplasia and skin inflammation in wild type mice but has no additional benefit in Trpv3 knockout mice in the carvacrol model. Scu is a potent and selective TRPV3 channel allosteric negative modulator with an apparent affinity of 1.18 μM. Molecular docking coupled with site-direct mutagenesis and covalent modification of incorporated cysteine residues demonstrate that Scu targets the cavity formed between the pore helix and transmembrane helix S6. Moreover, Scu attenuates endogenous TRPV3 activity in human keratinocytes and inhibits carvacrol-induced proliferative and proinflammatory responses.
Collectively, these data demonstrate that Scu ameliorates carvacrol-induced skin inflammation by directly inhibiting TRPV3, and TRPV3 represents a viable therapeutic target for AD treatment.
特应性皮炎（AD）是最常见的慢性炎症性皮肤病之一，存在未满足的临床需求。作为几种具有皮肤炎症疗效的草药中的常见成分，野黄芩素（Scu）已被证明具有抗炎和抗增殖作用。我们旨在评估 Scu 治疗 AD 的疗效及其潜在的分子机制。
在 2,4-二硝基氟苯（DNFB）和香芹酚诱导的皮炎小鼠模型中评估 Scu 的疗效。使用 qPCR 和 ELISA 分别检测细胞因子 mRNA 和血清 IgE 水平。使用电压钳记录测量瞬时受体电位（TRP）通道介导的电流。通过计算机对接、定点突变和共价修饰来探索 Scu 对 TRPV3 的结合口袋。
皮下给予 Scu 可有效抑制野生型小鼠的 DNFB 和香芹酚诱导的瘙痒、表皮增生和皮肤炎症，但在香芹酚模型中的 Trpv3 敲除小鼠中没有额外益处。Scu 是一种有效的 TRPV3 通道变构负调节剂，其表观亲和力为 1.18 μM。分子对接结合定点突变和结合的半胱氨酸残基的共价修饰表明，Scu 靶向孔螺旋和跨膜螺旋 S6 之间形成的腔。此外，Scu 可减弱人角质形成细胞中的内源性 TRPV3 活性，并抑制香芹酚诱导的增殖和促炎反应。
总之，这些数据表明，Scu 通过直接抑制 TRPV3 改善香芹酚诱导的皮肤炎症，TRPV3 是 AD 治疗的可行治疗靶点。
