Impact of cellular crosstalk on the cytochrome expression in an in vitro test system relevant for the alveolar barrier

Purpose: For humans, inhalation is considered as the main exposure route to chemicals, which is the reason why lung toxicity studies should be considered as a priority. Inhalation studies are often performed in vivo in rodents. Therefore, in vitro models may represent a valid and efficient alternative to predict the acute toxicity effects of inhaled chemicals on human health. The models used in this study are really simple in vitro systems either constituted by THP1 alone or THP1 cocultured with A549. This special designed has the purpose to study the impact of cellular cross talk on the THP 1 immune cells when exposed to a chemical which is BaP in the present work. Results: We describe the effects after 48 hours of exposure BaP in order to evaluate the importance of the cellular crosstalk in cell sensitivity toxicological effects of BaP. The set of parameters used to assess this cellular crosstalk included transcriptomics, cell imaging and enzymatic activity. The exposure did not cause any significant decrease of viability; all the parameters revealed the toxicity of the BaP. Regarding the global transcript, among differentially expressed genes (DEG) were found genes related to the enhancement of immune cells. Conclusion: Coculture in the used of in vitro model drastically change the gene expression profile in THP1 cells, but similar effects were observed between the monoculture and the culture exposed to BaP. However the number of altered mechanism in the THP1 cocultured cells exposed to BaP was larger supporting the importance to take into account the cell interactions. Overall design: THP1 mRNA profiles of 48h exposed mono and cocultured with A549 exposed to BaP in comparison to a negative control all in three biological replicates were analysed.

研究目的：对于人类而言，吸入被认为是化学品暴露的主要途径，因此肺部毒性研究应作为优先开展的方向。吸入毒性实验通常采用啮齿类动物体内模型进行。故此，体外模型可作为一种可靠且高效的替代方案，用于预测吸入类化学品对人体健康的急性毒性效应。本研究采用的体外模型体系极为简洁，仅包含单独培养的THP1细胞，或是THP1与A549细胞的共培养体系。本实验的特殊设计旨在探究：当暴露于本研究中的受试化学品苯并(a)芘（BaP）时，细胞间串扰对THP1免疫细胞的影响。

研究结果：本研究分析了细胞经BaP暴露48小时后的效应，以此评估细胞间串扰在BaP毒性效应的细胞敏感性中的作用。用于评估该细胞间串扰的检测参数涵盖转录组学分析、细胞成像及酶活性检测。实验结果显示，BaP暴露未引起细胞活力出现显著降低，但所有检测参数均证实了BaP的毒性效应。针对全局转录组分析结果，在差异表达基因（DEG）中发现了与免疫细胞活化增强相关的基因。

研究结论：采用共培养的体外模型会显著改变THP1细胞的基因表达谱，但单独培养组与BaP暴露组之间也呈现出相似的效应。不过，经BaP暴露的THP1共培养细胞中，发生表达改变的通路数量更多，这佐证了考量细胞间相互作用的必要性。

实验整体设计：本研究对三类样本开展了三次生物学重复的THP1 mRNA转录组分析，包括：经48小时BaP暴露的单独培养THP1细胞、经48小时BaP暴露的THP1与A549共培养细胞，以及未接受暴露的阴性对照组。