The Effect of Filaggrin Mutations on Dermal Penetration of Diisocyanates

摘要 在美国，很大一部分工人可能会因接触工业化学品而面临风险， 导致表皮屏障受损的遗传缺陷。皮肤的主要屏障是 表皮，其由形成皮质结构（层）的分化的角质形成细胞层组成 cornum，SC）。SC的连续性取决于脂质和结构蛋白的整合基质， 包括丝聚蛋白，其形成对外部环境的屏障。屏障的遗传决定因素 对完整性了解甚少。人类遗传学研究表明丝聚蛋白的完全或部分缺失 表达导致屏障功能降低和化学物质通过皮肤的渗透增强。的 丝聚蛋白对表皮分化和屏障功能的重要性已经变得明显， 聚丝蛋白基因（FLG）中的功能丧失（LOF）突变与慢性人类皮肤病的关联 疾病，寻常鱼鳞病和特应性湿疹。这些疾病的特点是皮肤干燥， 易患哮喘这些遗传性皮肤病的严重程度和发病率与 FLG突变体（LOF）等位基因的数量可能会被其他修饰基因改变。我们已经证明皮肤 暴露于二异氰酸酯（一种已知的呼吸道致敏物）可能会显著促进全身暴露。 我们假设皮肤中聚丝蛋白含量的部分损失（单倍不足）将损害屏障功能 导致增加的二异氰酸酯渗透、剂量和毒性。我们建议用以下方法来检验我们的假设： 具有和不具有受损屏障功能的体外三维（3D）人器官型皮肤组织。 模型接触和呼吸致敏物的渗透性和细胞毒性的剂量相关差异， 将在正常和屏障受损的人类皮肤中测量1，6-二异氰酸酯 重建。使用屏障受损的人类皮肤重建模型将满足以下重要需求： 生物学相关的方法来表征化学渗透到表皮，调查 皮肤暴露增加对皮肤和全身毒性的贡献，并确定个体（易感 亚群）的不良健康影响的风险增加，包括致敏、过敏和哮喘。的 拟议的研究代表了测试二异氰酸酯对人体皮肤毒性的最先进的暴露模型。 该模型测试系统的验证可以提供比目前使用2D的更合适的工具， 体外和动物模型，以研究皮肤暴露于化学呼吸致敏的作用。作为 因此，所建议的研究范围与NIOSH的目标和保护的使命是一致的，并扩大了NIOSH的目标和保护的使命 工人健康。我们有机会为NIOSH研究实践计划做出贡献， 新的知识和工具，以确定潜在的易感亚群，从而制定干预战略 并提供关键数据，以通过考虑个体差异来设定接触限值 改变暴露分类

ABSTRACT A significant portion of workers in the US could be at risk for an increase in exposure to industrial chemicals via a heritable defect resulting in a compromised epidermal barrier. The primary barrier of the skin is the epidermis, which consists of layers of differentiated keratinocytes forming a cornified structure (stratum corneum, SC). The continuity of the SC is dependent upon an integrated matrix of lipids and structural proteins, including filaggrin, that form a barrier against the external environment. The genetic determinants of barrier integrity are poorly understood. Human genetic studies suggest that the complete or partial loss of filaggrin expression results in decreased barrier function and enhanced penetration of chemicals through the skin. The importance of filaggrin to epidermal differentiation and barrier function has been made evident with the strong association of loss of function (LOF) mutations in the filaggrin gene (FLG) with the chronic human skin diseases, ichthyosis vulgaris and atopic eczema. These diseases are characterized by dry skin and a predisposition to asthma. The severity and penetrance of these heritable skin diseases are correlated with the number of FLG-mutant (LOF) alleles that may be altered by other modifier genes. We have shown that skin exposure to diisocyanates, a known respiratory sensitizer, may significantly contribute to systemic exposure. We hypothesize that partial loss (haploinsufficiency) of filaggrin content in the skin will impair barrier function resulting in increased diisocyanate penetration, dose, and toxicity. We propose to test our hypothesis by using in vitro three-dimensional (3D) human organotypic skin tissues with and without compromised barrier function. The dose-related difference in permeability and cellular toxicity to a model contact and respiratory sensitizer, 1,6-hexamethylene diisocyanate, will be measured in normal and barrier compromised human skin reconstructs. The use of a barrier-compromised human skin reconstruct model will fulfill an important need for biologically relevant methods to characterize chemical penetrance into the epidermis, to investigate the contribution of increased skin exposure to skin and systemic toxicity, and to identify individuals (susceptible subpopulation) at increased risk for adverse health effects, including sensitization, allergy, and asthma. The proposed research represents a cutting-edge exposure model for testing diisocyanate toxicity to human skin. Validation of this model test system can provide a more appropriate tool than is currently available using 2D in vitro and animal models to investigate the role of skin exposure to a chemical respiratory sensitization. As such, the scope of the research proposed is consistent with and amplifies NIOSH goals and mission to protect worker health. We have an opportunity to contribute to the NIOSH Research to Practice initiative by providing new knowledge and tools to identify potential susceptible subpopulations and, thus, strategies for intervention and control as well as to provide critical data to set exposure limits by taking into account individual variation that alter exposure classification.