Analysis of Acrolein Exposure Induced Pulmonary Response in Seven Inbred Mouse Strains and Human Primary Bronchial Epithelial Cells Cultured at Air-Liquid Interface

Abstract

Background. Acrolein is a major component of environmental pollutants, cigarette smoke, and is also formed by heating cooking oil. We evaluated the interstrain variability of response to subchronic inhalation exposure to acrolein among inbred mouse strains for inflammation, oxidative stress, and tissue injury responses. Furthermore, we studied the response to acrolein vapor in the lung mucosa model using human primary bronchial epithelial cells (PBEC) cultured at an air-liquid interface (ALI) to evaluate the findings of mouse studies. Methods. Female 129S1/SvlmJ, A/J, BALB/cByJ, C3H/HeJ, C57BL/6J, DBA/2J, and FVB/NJ mice were exposed to 1 part per million (ppm) acrolein or filtered air for 11 weeks. Total cell counts and protein concentrations were measured in bronchoalveolar lavage (BAL) fluid to assess airway inflammation and membrane integrity. PBEC-ALI models were exposed to acrolein vapor (0.1 and 0.2 ppm) for 30 minutes. Gene expression of proinflammatory, oxidative stress, and tissue injury-repair markers was assessed (cut off: ≥2 folds; p < 0.05 ) in the lung models. Results. Total BAL cell numbers and protein concentrations remained unchanged following acrolein exposure in all mouse strains. BALB/cByJ, C57BL/6J, and 129S1/SvlmJ strains were the most affected with an increased expression of proinflammatory, oxidative stress, and/or tissue injury markers. DBA/2J, C3H/HeJ, A/J, and FVB/NJ were affected to a lesser extent. Both matrix metalloproteinase 9 (Mmp9) and tissue inhibitor of metalloproteinase 1 (Timp1) were upregulated in the strains DBA/2J, C3H/HeJ, and FVB/NJ indicating altered protease/antiprotease balance. Upregulation of lung interleukin- (IL-) 17b transcript in the susceptible strains led us to investigate the IL-17 pathway genes in the PBEC-ALI model. Acrolein exposure resulted in an increased expression of IL-17A, C, and D; IL-1B; IL-22; and RAR-related orphan receptor A in the PBEC-ALI model. Conclusion. The interstrain differences in response to subchronic acrolein exposure in mouse suggest a genetic predisposition. Altered expression of IL-17 pathway genes following acrolein exposure in the PBEC-ALI models indicates that it has a central role in chemical irritant toxicity. The findings also indicate that genetically determined differences in IL-17 signaling pathway genes in the different mouse strains may explain their susceptibility to different chemical irritants.

Insight into the pulmonary molecular toxicity of heated tobacco products using human bronchial and alveolar mucosa models at air–liquid interface

“…The detailed protocol and details of cellular differentiation (Club cells, goblet cells, basal cells, ciliated cells, etc.) of the bro-ALI model has been described previously and the model has been in several studies 34 , 35 , 37 – 41 .…”

Countermeasures against Pulmonary Threat Agents

“…RNASeq analyses indicate sex-dependent differences in injury severity and increased neutrophil extracellular trap (NET) formation (Bein, Birru et al 2021). In vitro studies using acrolein vapor suggest interleukins (IL)1, IL22 and IL17 pathway genes play a central role in toxicity (Johanson, Dwivedi et al 2020). Potential therapies include chemosensory transient receptor potential A1 (TRPA1) antagonists (Conklin 2016), antioxidants (Hochman, Collaco et al 2014), and targeting claudin 5 (CLDN5) to preserve endothelial barrier integrity (Jang, Concel et al 2011).…”