Selenium-independent antioxidant and anti-inflammatory effects of thioredoxin reductase inhibition in alveolar macrophages.
Life Sci 2020;
259:118285. [PMID:
32798556 DOI:
10.1016/j.lfs.2020.118285]
[Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 08/08/2020] [Accepted: 08/11/2020] [Indexed: 01/10/2023]
Abstract
AIMS
Interleukin-1β (IL-1β) contributes to the development of bronchopulmonary dysplasia (BPD). Thioredoxin reductase-1 (Txnrd1) inhibition activates nuclear factor erythroid 2-related factor 2 (Nrf2)-dependent responses. Txnrd1 activity is selenium (Se) dependent and Se deficiency is common in prematurity. Auranofin (AFN), a Txnrd1 inhibitor, decreases IL-1β levels and increases Nrf2 activation in lipopolysaccharide (LPS) treated alveolar macrophages. In lung epithelia, AFN-induced Nrf2 activation is Se dependent. We tested the hypothesis that the effects of Txnrd1 inhibition in alveolar macrophages are Se dependent.
MAIN METHODS
To establish Se sufficient (Se+) and deficient (Se-) conditions, alveolar (MH-S) macrophages were cultured in 2.5% fetal bovine serum (FBS) ± 25 nM Na2SeO3. Se- (2.5% FBS) and Se+ (2.5% FBS + 25 nM Na2SeO3) cells were cultured in the presence or absence of 0.05 μg/mL LPS and/or 0.5 μM AFN. Nrf2 activation was determined by measuring NADPH quinone oxidoreductase-1 (Nqo1) and glutathione levels. IL-1β mRNA (Il1b) and protein levels were measured using qRT-PCR and ELISA. Data were analyzed by ANOVA followed by Tukey's post-hoc.
KEY FINDINGS
We detected an independent effect of AFN, but not LPS, on Nqo1 expression and GSH levels in Se+ and Se- cells. LPS significantly increased Il1b and IL-1β levels in both groups. AFN-mediated attenuation of this effect was not impacted by Se status.
SIGNIFICANCE
The beneficial effects of Txnrd1 inhibition in alveolar macrophages are Se-independent and therefore unlikely to be diminished by clinical Se deficiency.
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