Suppression of oxidant-induced glutathione synthesis by erythromycin in human bronchial epithelial cells.
BACKGROUND
Macrolide antibiotics have anti-inflammatory effects which are utilized for the treatment of chronic inflammatory airway diseases. Recently, their anti-inflammatory effects have been proposed to be beneficial in patients with chronic obstructive pulmonary disease (COPD).


OBJECTIVE
Since the molecular mechanisms of anti-inflammatory effects are associated with inhibition of activator protein 1 (AP-1) and nuclear factor (NF)-kappaB, and both are reported to be involved in the expression of gamma-glutamylcysteine synthetase (gamma-GCS), we set out to determine if these drugs influence the oxidant-antioxidant balance in human bronchial epithelial (HBE) cells.


METHODS
16HBE cells were preincubated with erythromycin (EM) at different concentrations and times and then exposed to hydrogen peroxide (0.01 mM). Levels of interleukin (IL)-8 and glutathione (GSH), and activity of gamma-GCS and gamma-GCS heavy subunit (gamma-GCS-HS) protein production were assayed. AP-1 and NF-kappaB binding to the 5'-flanking region of IL-8 and gamma-GCS-HS genes was assessed by electrophoretic mobility-shift assay.


RESULTS
The increase in IL-8 levels and activity of AP-1 induced by H(2)O(2) were abrogated by preincubation of the cells with EM (5 mug/ml) for 36 h. We also showed that preincubation with EM for 48 h inhibited H(2)O(2)-induced GSH levels, gamma-GCS activity and expression of gamma-GCS-HS, and decreased AP-1 binding to the gamma-GCS-HS 5'-flanking region.


CONCLUSIONS
The confirmation of antioxidants maintaining enzyme suppression by EM raised concerns on whether this drug could disrupt the oxidant/ antioxidant balance during long-term use. These data provide important insights into the treatment of inflammatory lung diseases with macrolide antibiotics.
He
Zhiyi
Z
Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical College, Guangzhou, PR China.
Li
Bing
B
Yu
Liang
L
Liu
Qicai
Q
Zhong
Nanshan
N
Ran
Pixin
P
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D004917:Erythromycin / Q000494:pharmacology*; D005721:Glutamate-Cysteine Ligase / Q000235:genetics / Q000378:metabolism; D005978:Glutathione / Q000096:biosynthesis*; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis; D016328:NF-kappa B / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism
D000900:Anti-Bacterial Agents; D016209:Interleukin-8; D016328:NF-kappa B; D018808:Transcription Factor AP-1; D004917:Erythromycin; D006861:Hydrogen Peroxide; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione