Simoneit Martin, Langer Helene, Ulrich Nadin, Böhme Alexander
UFZ Department of Exposure Science, Helmholtz Centre for Environmental Research, Permoserstraße 15, 04318 Leipzig, Germany.
Chem Res Toxicol. 2025 Jun 16;38(6):1046-1060. doi: 10.1021/acs.chemrestox.4c00545. Epub 2025 May 29.
The sensitization of the respiratory tract may lead to various pulmonary diseases such as asthma. It can be triggered by the chemical reaction of organic electrophiles with nucleophiles of lung proteins with amino groups being of particular interest in this case. For assessing the dermal sensitization potential of chemicals, the direct peptide reactivity assay (DPRA) has become an OECD-accepted nonanimal test system. However, issues with the identification of known respiratory sensitizers such as isocyanates and anhydrides based on their amino reactivity in the DPRA have been reported. Hence, in this study the chemoassay employing glycine--nitroanilide (Gly-pNA) as model nucleophile is applied to eight iso(thio)cyanates, seven anhydrides, four dinitrobenzenes, one triazine, five acrylates, glutaraldehyde, and chloramine T to quantify their amino reactivity in terms of the second order rate constant and the DPRA-like 24 h percent depletion . A comparison of with respective DPRA amino reactivity data () showed that in particular iso(thio)cyanates and anhydrides are substantially more reactive toward Gly-pNA. This can be rationalized by the unintentional and so far not considered reaction of the test compounds with the ammonium acetate buffer used for DPRA testing. A detailed analysis of this reaction includes half-lives and analytically determined adduct patterns and indicates that it can hamper the envisaged depletion of the DPRA amino nucleophile. Finally, the obtained log values range from -3.73 to ≥ 4.52 and allow for an improved identification of respiratory sensitizers. Hence, the Gly-pNA chemoassay may serve as a nonanimal screening method as one part of a mechanism-informed integrated testing and assessment strategy for respiratory sensitizers.
呼吸道致敏可能会导致各种肺部疾病，如哮喘。它可能由有机亲电试剂与肺蛋白亲核试剂的化学反应引发，在这种情况下，含氨基的肺蛋白尤其受关注。为评估化学品的皮肤致敏潜力，直接肽反应性测定法（DPRA）已成为经经济合作与发展组织（OECD）认可的非动物测试系统。然而，已有报告指出，基于DPRA中异氰酸酯和酸酐等已知呼吸道致敏剂的氨基反应性来进行识别存在问题。因此，在本研究中，采用甘氨酸 - 硝基苯胺（Gly - pNA）作为模型亲核试剂的化学分析方法被应用于八种异（硫）氰酸酯、七种酸酐、四种二硝基苯、一种三嗪、五种丙烯酸酯、戊二醛和氯胺T，以根据二级速率常数和类似DPRA的24小时消耗百分比来量化它们的氨基反应性。将 与各自的DPRA氨基反应性数据（）进行比较表明，特别是异（硫）氰酸酯和酸酐对Gly - pNA的反应性明显更高。这可以通过测试化合物与用于DPRA测试的醋酸铵缓冲液发生意外且迄今未被考虑的反应来解释。对该反应的详细分析包括半衰期和分析确定的加合物模式，并表明它可能会阻碍DPRA氨基亲核试剂预期的消耗。最后，获得的log 值范围从 - 3.73至≥4.52，有助于更好地识别呼吸道致敏剂。因此，Gly - pNA化学分析方法可作为一种非动物筛选方法，作为呼吸道致敏剂的基于机制的综合测试和评估策略的一部分。
