Sulfur mustard analog 2-chloroethyl ethyl sulfide increases triglycerides by activating DGAT1-dependent biogenesis and inhibiting PGC1ɑ-dependent fat catabolism in immortalized human bronchial epithelial cells

Abstract

Using sulfur mustard analog 2-chloroethyl ethyl sulfide (CEES), we established an in vitro model by poisoning cultured immortalized human bronchial epithelial cells. Nile Red staining revealed lipids accumulated 24 h after a toxic dose of CEES (0.9 mM). Lipidomics analysis showed most of the increased lipids were triglycerides (TGs), and the increase in TGs was further confirmed using a Triglyceride-Glo™ Assay kit. Protein and mRNA levels of DGAT1, an important TG biogenesis enzyme, were increased following 0.4 mM CEES exposure. Under higher dose CEES (0.9 mM) exposure, protein and mRNA levels of PPARγ coactivator-1ɑ (PGC-1ɑ), a well-known transcription factor that regulates fatty acid oxidation, were decreased. Finally, application with DGAT1 inhibitor A 922500 or PGC1ɑ agonist ZLN005 was able to block the CEES-induced TGs increase. Overall, our dissection of CEES-induced TGs accumulation provides new insight into energy metabolism dysfunction upon vesicant exposure. HIGHLIGHTS In CEES (0.9 mM)-injured cells: Triglycerides (TGs) were abundant in the accumulated lipids. Expression of DGAT1, not DGAT2, was increased. Expression of PGC1ɑ, not PGC1β, was reduced. DGAT1 inhibitor or PGC1ɑ agonist blocked the CEES-mediated increase in TGs.