Figure 1.

Cigarette smoke extract induces a modest induction of CHOP in SAE cells, bronchial epithelial cells, and macrophages. SAE cells were exposed to various concentrations of CSE for 24 hours and high CSE concentrations result in reduced viability (A) and no increase of CHOP protein levels (B). C) CHOP protein levels were elevated following 24 hours exposure to 5% CSE, demonstrated by qPCR. Exposures to thapsigargin (1 μM) or tunicamycin (1 μM) were used as positive ER stress controls. D) This CSE induction of CHOP protein was undetectable from 1 to 48 hours, by Western blot. A modest induction of CHOP is observed in HBE and THP-1 cells but not in HMVEC following 5% CSE exposure for 24 hours, at the mRNA level (E) but undetectable by Western blot analysis (F).

Notes: Each assay was performed on 4 independent days and graphs are represented as mean ± S.E.M. P-values shown, comparing cells not treated to CSE.

Abbreviations: CHOP, C/EBP homologous protein; CSE, cigarette smoke extract; ER, endoplasmic reticulum; HBE, human bronchial epithelial; HMVEC, human pulmonary endothelial cells; SAE, small airway epithelial.