利用待测物再生型荧光探针研究甲醛对巨噬细胞的免疫毒性

Formaldehyde is a widely-used chemical in industry. It is also an indoor environmental pollutant that attracts extensive public attention. Formaldehyde is classified by International Agency for Research on Cancer of WHO as a Group I carcinogen. It is known as an essential intermediate product in the one-carbon metabolic pathway mediated by folate. Macrophages are differentiated by monocytes. As an important member of the innate immune system, macrophages eliminate the aged and apoptotic cells, pathogens and cancer cells in vivo through phagocytosis and digestion. To study the immunotoxicity induced by formaldehyde in macrophages, we previously designed and synthesized highly-sensitive analyte regeneration formaldehyde fluorescent probes which can target cellular cytoplasm or lysosomes. We also made an in vitro model of human macrophages that can be utilized in this study. The dose-response curve will be set up between the concentrations of formaldehyde in the cytosol or lysosomes and the major immune functions of macrophages using these probes and cell models. Further study on the molecular mechanisms of the observed immunotoxicity will also be performed to identify the potential protein targets for the prevention and treatment of the toxic effects induced by formaldehyde. Concentrations of endogenous formaldehyde will be tested as a biomarker for the immune functions of macrophages. This interdisciplinary research project is going to reveal the immunotoxicity of formaldehyde in macrophages with novel and practical tools and models, which will provide not only the scientific evidence for the prevention and treatment of formaldehyde toxicity, but also valuable reference for health risk assessment. The results of the study will also provide clues for future studies on the biological effects of formaldehyde and one-carbon metabolism.

甲醛是化工生产中的常用原料和受到广泛关注的室内环境污染物，是WHO下属国际癌症研究机构划定的一类致癌物，同时也是叶酸介导的一碳代谢通路的重要中间产物。巨噬细胞由单核细胞分化而来，能够吞噬和消化体内衰老并凋亡的细胞、病原体和癌细胞，是先天免疫系统的重要成员。为了研究甲醛对巨噬细胞的免疫毒性，我们在前期研究中已设计合成了高灵敏度的胞质和靶向溶酶体的待测物再生型甲醛荧光探针，建立了体外巨噬细胞模型。我们将利用这些工具和模型，通过建立胞质和溶酶体内甲醛浓度与巨噬细胞主要免疫功能的量效关系，进一步探索甲醛对巨噬细胞的毒理效应和分子机制，寻找防治甲醛毒性的可能靶点，并尝试利用内源性甲醛浓度评价巨噬细胞的免疫功能的变化。该项目通过学科交叉互补，利用新颖实用的工具和模型研究甲醛对巨噬细胞的免疫毒性，研究成果将为甲醛的防治和风险评估提供科学依据，为研究甲醛和一碳代谢的生物学效应提供有力参考。

甲醛是常见的室内环境污染物，也是是WHO下属国际癌症研究机构划定的一类致癌物，但甲醛的致癌机制和免疫毒性尚未被研究清楚。本项目聚焦甲醛对固有免疫中发挥重要功能的巨噬细胞代谢和功能的影响。利用甲醛暴露的小鼠和巨噬细胞体外模型，首次发现了甲醛对巨噬细胞糖酵解代谢的促进效应。低浓度的甲醛（50到200微摩尔）通过上调HIF-1α信号通路降低巨噬细胞氧化磷酸化，刺激糖酵解代谢，促进巨噬细胞向促炎型M1极化，诱发组织和微环境中的炎症反应。在此基础上，我们设计并合成了在微环境中检测糖酵解代谢中间产物丙酮醛的荧光探针NAP-DCP-4，并利用该探针确定了丙酮醛对巨噬细胞极化的影响。通过抑制HIF-1α信号通路，我们发现了减轻甲醛免疫毒性的方法，并首次发现天然产物杨梅酮对HIF-1α的抑制功能。综上所述，该项目的成果不仅揭示了甲醛通过促进巨噬细胞糖酵解代谢增强其促炎效应的分子机制，也为甲醛免疫毒性的防治提供了重要的参考。