基于E-Cadherin介导黑素细胞经表皮脱失探讨补肝益肾法治疗白癜风的机制

The number of the melanocytes switches repigmentation or depigmentation. It is well established that transepidermal loss of melanocytes is mediated by the malfunction of E-cadherin (Ecad) which is responsible for the decreased attachment ability of melanocytes to the basilar layer both in the lesional and normal pigmented skin of vitiligo. In 2015, authorities stress the importance on systemic and non-lesional management, which disclosed a perfect chance to show the international peers the effectiveness of TCM in vitiligo treatment. Transepidermal loss of melanocytes is an abnormal type of drainage as miscarriage, which similarly is the obvious sign of Nonfunctioning of the Preserving and Discharging by the Liver and the Kidney. Therefore, Tonifying the liver and the kidney to recover normal adhesive function of Ecad is the pivotal point in the handling of such patients. In this research, melanocytes or the co-culture system of melanocytes and keratinocytes are pretreated with serum from patients with the Syndrome of Deficiency of the Kidney and Liver(SDKL), as well as other common syndromes. Herbs functioning to Tonify the Kidney and Liver(TKL) are added with PBS set as the control. This research aims to test or observe①the adhesive rate of the melanocytes；②dendrite morphology, adhesive band and distribution of Ecad under atomic microscopy and other methods; ③ the mRNA and protein expression of Ecad and its regulators, as well as their phosphoration states after specific inhibitors are applied. Our research is destined to approve that defective adhesive ability of the melanocytes is the key feature of the SDKL vitiligo patient; TKL behaves to recover its depressed adhensive abitility possibly through protect the melanocytes from transepidermal loss. Findings of this research will add an additional choice for its systemic treatment or pretreatment of unidenfiable lesion beside this unique choice of oral corticorsteroids.

黑素细胞(MC)盈亏是白癜风脱色/复色扳击点。“黑素细胞经表皮脱失”已被反复确证：白癜风皮损及非皮损处上皮型钙粘蛋白(Ecad)所介导MC粘附力降低使其从基底层解离并经表皮排出而发白斑。2015年国际权威回调防治重心至系统治疗及非皮损处的“未病先防”，为扬我中医提供了契机。鉴于补肝益肾为白癜风诸法之首，且MC脱失与滑胎等同为病理性施“泄”现象，与肝肾藏泄失职密切相关。本课题拟以肝肾不足证等患者血清，旱莲草等补肝益肾药序贯干预MC或共培养MC/角质形成细胞后，①测定MC粘附率；②原子力显微镜等观察各级树突形态、粘附带结构及Ecad分布情况；③测定各组Ecad及主要调控分子mRNA、蛋白表达及磷酸化状态。印证MC粘附功能下降是白癜风肝肾不足证主要特点；补肝益肾法能作用Ecad等而恢复受损MC粘附功能，斩断“黑素细胞经表皮脱失”病理关键。研究成果将撼动“未病”白癜风及其系统治疗仅口服激素的窘况。

白癜风是一种获得性色素脱失性疾病，影响患者容貌，长期不愈易情绪焦虑、抑郁，危害患者身心健康。因此，深入研究白癜风的发病机制，探索治疗的新靶点有着重要的临床意义。白癜风皮损处黑素细胞所剩无几，其发病机制虽未完全阐明，但目前多以黑素细胞经表皮脱落学说、氧化应激学说、遗传易感、自身免疫等解释。稳定黑素细胞粘附是预防白癜风非皮损地区黑素细胞脱失的潜在治疗目标，这恰恰与中医治疗所提倡的“未病先防、治未病”不谋而合。临床高频使用的补肝益肾药物二至丸（女贞子、墨旱莲）水提物可以促进人原代黑素细胞增殖、黑素合成，其机理与上调MITF、TYR、TRP1、TRP2蛋白的表达来有关。同时二至丸可以促进人原代黑素细胞对角质形成细胞的粘附，其机理与上调Ecad蛋白表达，维持其正常分布，重塑细胞骨架有关。氧化应激状态下，黑素细胞粘附相关分子表达受到抑制（Ecad、β-catenin、DDR1、CCN3），细胞骨架受到破坏，损伤了黑素细胞的粘附功能，细胞超微结构被破坏，细胞凋亡加速。同时，角质形成细胞“助纣为虐”，上调MMP9的表达，降解细胞外基质，营造出有利于黑素细胞脱失的外部环境，最终造成白斑的发生。二至丸水提物可以对上述环节有明显的改善保护作用，可以明显改善氧化应激状态下Ecad、β-catenin、DDR1、CCN3表达障碍的现象，使受损的细胞骨架部分恢复，减轻了细胞超微结构的损伤，减少细胞凋亡，下调角质形成细胞MMP9的表达，防止了黑素细胞经表皮脱落。通过研究中医药对黑素细胞的分化、粘附影响及机制可以为白癜风的治疗提供候选药物和新思路。