Comparison of the effects of betamethasone and dexamethasone on surfactant protein A mRNA expression in human lung cells. (July 2015)

• Record Type: Journal Article
• Authors: Fonseca, Linda; Alcorn, Joseph L.; Ramin, Susan M.; Vidaeff, Alex C.
• Is Part Of: Journal of maternal-fetal & neonatal medicine. Volume 28:Number 11(2015)
• Page Start: 1239
• Page End: 1243
• Publication Date: 2015-07
• Subjects: Obstetrics -- Periodicals; Perinatology -- Periodicals; Infants (Newborn) -- Diseases -- Periodicals; Neonatology -- Periodicals; 618.2
• Languages: English
• ISSNs: 1476-7058

Abstract

<abstract> <title>Abstract</title> <p> <italic>Objective</italic>: While prenatal administration of synthetic corticosteroids stimulates both fetal lung development and expression of pulmonary surfactant, the specific effects may depend on the corticosteroid formulation used. We compared the dose-dependent effects of various concentrations of two synthetic corticosteroids, betamethasone and dexamethasone, on steady state levels of surfactant protein A (SP-A) mRNA in human lung cells.</p> <p> <italic>Methods</italic>: Cultured human NCI-H441 bronchoalveolar epithelial cells were exposed to varying concentrations of betamethasone or dexamethasone (10<sup>−7</sup> to 10<sup>−12</sup> M) for 48 h alone or in combination with dibutyryl cAMP (1 mM), which augments surfactant protein gene expression. RNA was harvested and SP-A mRNA levels were quantified by real-time quantitative reverse transcriptase polymerase chain reaction analysis. Results were compared using the Kruskal–Wallis test.</p> <p> <italic>Results</italic>: A dose-dependent modification in SP-A mRNA levels was demonstrated with both dexamethasone and betamethasone. Cells treated with cAMP expressed higher levels of SP-A mRNA than untreated cells. A biphasic curve in the SP-A mRNA response to corticosteroids was elicited only in the presence of cAMP: at lower concentrations (10<sup>−10</sup> through 10<sup>−12</sup> M), SP-A mRNA levels were upregulated, whereas at higher concentrations (10<sup>−7</sup> and 10<sup>−8</sup> M), SP-A mRNA levels were reduced. Dexamethasone was more effective than betamethasone in inducing these changes.</p> <p> <italic>Conclusions</italic>: Our results support a biphasic effect on SP-A mRNA levels after exposure to corticosteroids in combination with cAMP. At higher corticosteroid concentrations, betamethasone is less inhibitory than dexamethasone on SP-A mRNA.</p> </abstract>