Dihydroxyacetone exposure induces metabolic reprogramming and mitochondrial dysfunction

每吸一口电子烟都会产生微摩尔量的二羟基丙酮(DHA)。 丙二醇和甘油。高达40%-55%的电子液体含量在每一次电子烟中被转化为DHA- 香烟，使DHA成为所有电子烟蒸气中的高含量成分，纸巾用它来吸入 每一口电子烟。DHA被批准作为不晒黑的外部使用，但很严重 人们对喷雾晒黑和现在使用电子烟导致的吸入暴露表示担忧。我们 已证明DHA具有遗传毒性、细胞毒性，并导致皮肤和肾脏细胞线粒体功能障碍， 但吸入暴露于DHA的影响目前尚不清楚。该提案的长期目标是 DHA暴露诱导的细胞和代谢应激标志物的鉴定和验证 在尿布组织中进行检查，以了解反复吸入DHA的后果。 这项建议的目的是解决现有研究中的差距，这些研究只关注皮肤 模型，通过检测急性和慢性剂量DHA对肺和肺组织的暴露影响 心血管细胞。我们的中心假设是，接触DHA会改变代谢途径，促进 氧化应激，破坏钙离子的稳态，并导致线粒体功能障碍。这样做的理由是 工作是DHA暴露在肺和心血管系统中，使DHA能够直接被细胞吸收。 DHA诱导的新陈代谢和线粒体功能的变化会损害整体细胞功能， 导致疾病。三个特定的目标将检验中心假设：1)DHA参与代谢 途径改变糖酵解并诱导糖基化蛋白损伤；2)DHA暴露改变NAD(P)H池 诱导氧化应激，以及3)DHA暴露改变细胞内钙水平并破坏线粒体 功能。第一个目标是测试DHA通过追踪DHA改变代谢途径的假设 利用DHA的同位素制剂进行代谢，并确定代谢物的不平衡。第二个目标将测试 DHA过量改变辅因子库并诱导氧化应激的假设。第三个目标将是 测试DHA改变钙信号以诱导线粒体功能障碍的亚假说 造成代谢应激和氧化还原失衡。这项研究具有创新性，因为它扩展了 除了DHA的遗传毒性和细胞毒性特征外，还可以测量DHA重新编程肺组织的能力 和心血管细胞的代谢。这项研究意义重大，因为电子烟使用者是慢性 暴露于DHA，会直接影响肺和心血管细胞的稳态，并导致严重的 细胞功能下降，甚至导致细胞死亡。这项工作将为DHA建立必要的标记 使今后的流行病学工作能够将DHA暴露与疾病联系起来。

Each puff of an e-cigarette generates micromolar amounts dihydroxyacetone (DHA) from the combustion of propylene glycol and glycerol. Up to 40-55% of e-liquid content is converted to DHA in each puff from an e- cigarette, making DHA a high-volume component found in all e-cigarette vapors, which the vaper inhales with each puff of the e-cigarette. DHA is approved for external use as a sunless tanning agent, but serious concerns have been raised about inhalation exposures through spray tanning and now e-cigarette use. We have shown that DHA is genotoxic, cytotoxic, and induces mitochondrial dysfunction in skin and kidney cells, but the effects of inhalation exposures to DHA are currently unknown. The long-term goal of the proposal is the identification and validation of markers for cellular and metabolic stress induced by DHA exposure that can be examined in tissues from vapers to understand the consequences of repeated inhalation exposures to DHA. The objective of this proposal is to address the gap in existing studies, which have only focused on skin models, by examining the exposure effects of DHA at both acute and chronic doses in pulmonary and cardiovascular cells. Our central hypothesis is that exposure to DHA alters metabolic pathways, promotes oxidative stress, disrupts Ca2+ homeostasis, and leads to mitochondrial dysfunction. The rationale for this work is that DHA exposures to the lung and cardiovascular system allow direct absorption of DHA into cells. DHA-induced changes in metabolism and mitochondrial function would compromise overall cellular function, leading to disease. Three specific aims will test the central hypothesis: 1) DHA incorporation into metabolic pathways alters glycolysis and induces glycosylation protein damage; 2) DHA exposure alters NAD(P)H pools inducing oxidative stress, and 3) DHA exposure alters cytosolic Ca2+ levels and disrupts mitochondrial function. The first aim will test the sub-hypothesis that DHA alters metabolic pathways by tracing DHA metabolism using isotopologues of DHA and identifying metabolite disequilibrium. The second aim will test the sub-hypothesis that an excess of DHA changes cofactor pools and induces oxidative stress. The third aim will test the sub-hypothesis that DHA alters Ca2+ signaling to induce mitochondrial dysfunction, in addition to causing metabolic stress and oxidation-reduction imbalance. The study is innovative because it extends beyond the genotoxic and cytotoxic characterization of DHA to measure DHA’s ability to reprogram pulmonary and cardiovascular cells metabolically. The research is significant because e-cigarette users are chronically exposed to DHA, which will directly impact pulmonary and cardiovascular cell homeostasis and cause severe declines in cellular function or even induce cell death. This work will establish essential markers for DHA exposure to allow future epidemiological work to associate DHA exposure to disease.