Liao Zhikai, Yao Yunzhu, Dong Bingqi, Le Yue, Luo Longfei, Miao Fang, Jiang Shan, Lei Tiechi
Department of Dermatology, Renmin Hospital of Wuhan University, Wuhan, Hubei 430060, China.
Chin Med J (Engl). 2024 Sep 30. doi: 10.1097/CM9.0000000000003173.
Increasing evidence indicates that oxidative stress and interferon γ (IFNγ)-driven cellular immune responses are responsible for the pathogenesis of vitiligo. However, the connection between oxidative stress and the local production of IFNγ in early vitiligo remains unexplored. The aim of this study was to identify the mechanism underlying the production of IFNγ by mast cells and its impact on vitiligo pathogenesis.
Skin specimens from the central, marginal, and perilesional skin areas of active vitiligo lesions were collected to characterize changes of mast cells, CD8+ T cells, and IFNγ-producing cells. Cell supernatants from hydrogen peroxide (H2O2)-treated keratinocytes (KCs) were harvested to measure levels of soluble stem cell factor (sSCF) and matrix metalloproteinase (MMP)-9. A murine vitiligo model was established using Mas-related G protein-coupled receptor-B2 (MrgB2, mouse ortholog of human MrgX2) conditional knockout (MrgB2-/-) mice to investigate IFNγ production and inflammatory cell infiltrations in tail skin following the challenge with tyrosinase-related protein (Tyrp)-2 180 peptide. Potential interactions between the Tyrp-2 180 peptide and MrgX2 were predicted using molecular docking. The siRNAs targeting MrgX2 and the calcineurin inhibitor FK506 were also used to examine the signaling pathways involved in mast cell activation.
IFNγ-producing mast cells were closely aligned with the recruitment of CD8+ T cells in the early phase of vitiligo skin. sSCF released by KCs through stress-enhanced MMP9-dependent proteolytic cleavage recruited mast cells into sites of inflamed skin (Perilesion vs. lesion, 13.00 ± 4.00/HPF vs. 26.60 ± 5.72/HPF, P <0.05). Moreover, IFNγ-producing mast cells were also observed in mouse tail skin following challenge with Tyrp-2 180 (0 h vs. 48 h post-recall, 0.00 ± 0.00/HPF vs. 3.80 ± 1.92/HPF, P <0.05). The IFNγ+ mast cell and CD8+ T cell counts were lower in the skin of MrgB2-/-mice than in those of wild-type mice (WT vs. KO 48 h post-recall, 4.20 ± 0.84/HPF vs. 0.80 ± 0.84/HPF, P <0.05).
Mast cells activated by MrgX2 serve as a local IFNγ producer that bridges between innate and adaptive immune responses against MCs in early vitiligo. Targeting MrgX2-mediated mast cell activation may represent a new strategy for treating vitiligo.
越来越多的证据表明，氧化应激和干扰素γ（IFNγ）驱动的细胞免疫反应是白癜风发病机制的原因。然而，早期白癜风中氧化应激与局部IFNγ产生之间的联系仍未得到探索。本研究的目的是确定肥大细胞产生IFNγ的机制及其对白癜风发病机制的影响。
收集活动期白癜风皮损中央、边缘和皮损周围皮肤区域的皮肤标本，以表征肥大细胞、CD8 + T细胞和产生IFNγ的细胞的变化。收集过氧化氢（H2O2）处理的角质形成细胞（KC）的细胞上清液，以测量可溶性干细胞因子（sSCF）和基质金属蛋白酶（MMP）-9的水平。使用Mas相关G蛋白偶联受体-B2（MrgB2，人类MrgX2的小鼠同源物）条件性敲除（MrgB2-/-）小鼠建立小鼠白癜风模型，以研究用酪氨酸酶相关蛋白（Tyrp）-2 180肽攻击后尾皮肤中IFNγ的产生和炎性细胞浸润。使用分子对接预测Tyrp-2 180肽与MrgX2之间的潜在相互作用。还使用靶向MrgX2的小干扰RNA和钙调神经磷酸酶抑制剂FK506来检查肥大细胞激活中涉及的信号通路。
在白癜风皮肤早期，产生IFNγ的肥大细胞与CD8 + T细胞的募集紧密相关。KC通过应激增强的MMP9依赖性蛋白水解切割释放的sSCF将肥大细胞募集到炎症皮肤部位（皮损周围与皮损，13.00±4.00/HPF对26.60±5.72/HPF，P<0.05）。此外，在用Tyrp-2 180攻击后，在小鼠尾皮肤中也观察到产生IFNγ的肥大细胞（回忆后0小时与48小时，0.00±0.00/HPF对3.80±1.92/HPF，P<0.05）。MrgB2-/-小鼠皮肤中的IFNγ+肥大细胞和CD8 + T细胞计数低于野生型小鼠（WT与KO，回忆后48小时，4.20±0.84/HPF对0.80±0.84/HPF，P<0.05）。
由MrgX2激活的肥大细胞作为局部IFNγ产生者，在早期白癜风中连接针对MC的先天性和适应性免疫反应。靶向MrgX2介导的肥大细胞激活可能代表一种治疗白癜风的新策略。
