Cigarette smoke irreversibly modifies glutathione in airway epithelial cells.
In patients with chronic obstructive pulmonary disease (COPD), an imbalance between oxidants and antioxidants is acknowledged to result in disease development and progression. Cigarette smoke (CS) is known to deplete total glutathione (GSH + GSSG) in the airways. We hypothesized that components in the gaseous phase of CS may irreversibly react with GSH to form GSH derivatives that cannot be reduced (GSX), thereby causing this depletion. To understand this phenomenon, we investigated the effect of CS on GSH metabolism and identified the actual GSX compounds. CS and H(2)O(2) (control) deplete reduced GSH in solution [Delta = -54.1 +/- 1.7 microM (P < 0.01) and -39.8 +/- 0.9 microM (P < 0.01), respectively]. However, a significant decrease of GSH + GSSG was observed after CS (Delta = -75.1 +/- 7.6 microM, P < 0.01), but not after H(2)O(2). Exposure of A549 cells and primary bronchial epithelial cells to CS decreased free sulfhydryl (-SH) groups (Delta = -64.2 +/- 14.6 microM/mg protein, P < 0.05) and irreversibly modified GSH + GSSG (Delta = -17.7 +/- 1.9 microM, P < 0.01) compared with nonexposed cells or H(2)O(2) control. Mass spectrometry (MS) showed that GSH was modified to glutathione-aldehyde derivatives. Further MS identification showed that GSH was bound to acrolein and crotonaldehyde and another, yet to be identified, structure. Our data show that CS does not oxidize GSH to GSSG but, rather, reacts to nonreducible glutathione-aldehyde derivatives, thereby depleting the total available GSH pool.
van der Toorn
Marco
M
Laboratory of Allergy and Pulmonary Diseases, Univ. Medical Center Groningen, PO Box 30001, 9700 RB Groningen, Groningen, The Netherlands.
Smit-de Vries
Maria P
MP
Slebos
Dirk-Jan
DJ
de Bruin
Harold G
HG
Abello
Nicolas
N
van Oosterhout
Antoon J M
AJ
Bischoff
Rainer
R
Kauffman
Henk F
HF
D001980:Bronchi / Q000166:cytology; D002478:Cells, Cultured / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D006801:Humans; D008168:Lung / Q000378:metabolism*; D013058:Mass Spectrometry; D016877:Oxidants / Q000494:pharmacology; D010084:Oxidation-Reduction; D020545:Respiratory Mucosa / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism*
D016877:Oxidants; D005978:Glutathione; D019803:Glutathione Disulfide