Melanocyte precursors in the hair follicle bulge of repigmented vitiligo skin are controlled by RHO-GTPase, KCTD10 and CTNNB1 signaling

In repigmentation of human vitiligo, the melanocyte (MC) precursors in the hair follicle (HF) bulge proliferate, migrate and differentiate to repopulate the depigmented epidermis. Here we present a comprehensive characterization of pathways and signals in the bulge that control the repigmentation process. Using biopsies from vitiligo patients we have selectively harvested, by laser capture microdissection, MC and keratinocyte precursors from the HF bulge of untreated vitiligo skin and vitiligo skin treated with Narrow Band UVB (NBUVB). The captured material was subjected to whole transcriptome RNA sequencing. With this strategy, we found that repigmentation in the bulge MCs precursors is driven by KCTD10, a signal with unknown roles in the skin, and by CTNNB1 (encoding ß-catenin) and RHO-GTPase (RHO), two signaling pathways previously shown to be involved in pigmentation biology. Overall design: 1)Gene expression profiles of hair follicle bulge melanocyte precursor samples (MCBG) from 6 vitiligo patients undergoing active NBUVB treatment were compared to gene expression profiles of hair follicle bulge melanocyte precursor samples (MCBG) from 6 untreated vitiligo patients; 2)Gene expression profiles of hair follicle bulge outer root sheath keratinocyte samples (KCBG) from 6 vitiligo patients undergoing active NBUVB treatment were compared to gene expression profiles of hair follicle bulge outer root sheath keratinocyte samples (KCBG) from 6 untreated vitiligo patients. Both comparisons utilized F-LCM on full-thickness skin biopsies. 100 captured cells were pooled for each sample, RNA was extracted, amplified, and subjected to whole transcriptome RNA-Seq.

在人类白癜风的色素再生过程中，毛囊（hair follicle, HF）隆突区的黑素细胞（melanocyte, MC）前体可发生增殖、迁移与分化，从而重新填充脱色素的表皮层。本研究针对调控该色素再生进程的隆突区通路与信号分子展开了全面表征。我们通过激光捕获显微切割技术，从未接受治疗的白癜风患者与接受窄谱中波紫外线（Narrow Band UVB, NBUVB）治疗的白癜风患者的皮肤毛囊隆突区，选择性采集了黑素细胞前体与角质形成细胞前体。对捕获得到的样本进行了全转录组RNA测序。通过该实验策略，我们发现隆突区黑素细胞前体的色素再生过程由KCTD10（一种在皮肤中功能尚未明确的信号分子）、以及此前已被证实与色素生物学相关的CTNNB1（编码β-连环蛋白）和RHO-GTP酶（RHO）信号通路所驱动。本研究的整体实验设计如下：1）将6名接受活性NBUVB治疗的白癜风患者的毛囊隆突区黑素细胞前体样本（MCBG）的基因表达谱，与6名未接受治疗的白癜风患者的同类型样本进行对比分析；2）将6名接受活性NBUVB治疗的白癜风患者的毛囊隆突区外根鞘角质形成细胞样本（KCBG）的基因表达谱，与6名未接受治疗的白癜风患者的同类型样本进行对比分析。两组对比均采用全层皮肤活检样本的F-LCM技术。每个样本混合100个捕获细胞，提取RNA并进行扩增，随后开展全转录组RNA测序。