Erythropoietin inhibits respiratory epithelial cell apoptosis in a model of acute lung injury

Abstract

Fas-mediated apoptosis of the alveolar epithelium is important in the pathogenesis of acute respiratory distress syndrome. Erythropoietin (EPO) has cytoprotective properties in other organ systems, and is relatively deficient in critical illness. This study investigates a potential role for EPO in reducing apoptosis in a model of acute lung injury.Apoptosis was induced in human alveolar epithelial (A549) cells or normal human bronchial epithelial (NHBE) cells by Fas activation with CH-11 Fas-crosslinking antibody or by co-culture with polymorphonuclear neutrophils in a transwell system. The effect of recombinant human (rh)EPO on apoptosis was measured by poly(ADP-ribose) polymerase cleavage and cell death detection assay. The specific EPO-EPO receptor (EPOR)-mediated effect was determined using an EPO-blocking antibody or EPOR small interfering RNA.Expression of EPOR was demonstrated in A549, NHBE and normal human alveolar epithelium. Fas-and neutrophil-mediated apoptosis of A549 and NHBE cells was inhibited by rhEPO by a specific EPO-EPOR-mediated mechanism. This anti-apoptotic effect was associated with induction of a pro-apoptotic Bcl-xL/Bax ratio.EPO has cytoprotective properties in respiratory epithelium in an in vitro model, which may indicate a potential therapeutic role in acute lung injury.

Inhibition of endotoxin-induced airway epithelial cell injury by a novel family of pyrrol derivates

“…Second, we did not use primary alveolar epithelial cells; however, there is a plethora of published studies validating the use of human BEAS-2B and A549 cells as an acceptable model of epithelial cell injury and for studying the LPS-induced effects in the airway epithelium. [11][12][13][14][15][16]25,[28][29][30][31][32][33][34][35] Third, further studies are needed to elucidate whether there are other mechanisms by which the pyrrol compound DTA0118 elicits its anti-inflammatory and antiapoptotic activities. Fourth, TLR4, Ikβα, and β-actin were not adjusted for the cell number.…”

“…We chose A549 and BEAS-2B cell lines as representative human alveolar and bronchial epithelial cells because they have been implicated in the pathogenesis of sepsis-induced ARDS. [11][12][13][14][15][16] One of the most important determinants of lung severity is the magnitude of injury to the epithelial barrier. 2 Epithelial cells generate cytokines, chemokines, and antimicrobial peptides in response to inflammatory stimuli, 25,26 and airway epithelium controls lung inflammation and injury through NF-κB.…”

“…2 Epithelial cells generate cytokines, chemokines, and antimicrobial peptides in response to inflammatory stimuli, 25,26 and airway epithelium controls lung inflammation and injury through NF-κB. 27 Numerous experimental studies have used human A549 alveolar and BEAS-2B bronchial epithelial cell lines to examine the acute lung inflammatory response induced by LPS, as an acceptable, validated, and suitable in vitro airway epithelial injury model based on the initial steps of the development of sepsis and ARDS [11][12][13][14][15][16]25,[28][29][30] and continue being extensively used. [31][32][33][34][35] We selected E. coli LPS because it has been used in most endotoxin-induced lung injury models 36,37 and LPS is a key pathogen recognition molecule for sepsis 27 that induces apoptosis in lung cells.…”

“…Based on a well-established protocol of the National Cancer Institute of the United States, 9 we used a validated screening strategy to identify potential therapeutic molecules by examining the effects of a novel family of tri-and tetrasubstituted pyrrols, which were previously studied by our group. 10 In the present study, we report the marked anti-inflammatory and antiapoptotic properties of a compound termed by us as DTA0118 in a well-established in vitro LPSinduced airway epithelial cell injury model, [11][12][13][14][15][16] based on the initial steps of the development of sepsis and sepsis-induced ARDS, using human alveolar A549 and human bronchial BEAS-2B cells. We used rhein and emodin, two anthracenederived anthraquinones with proven activity against the effects of LPS, 17 as reference compounds.…”

Endogenous erythropoietin level and effects of exogenous erythropoietin in a rat model of blunt chest trauma -induced pulmonary contusion

“…[18] Increase in CAT activity during hypoxia indicates presence of oxidative stress, and may be an adaptive response aimed to protect mitochondria from elevated levels of H 2 O 2 . [18,24,25] CAT is an important intracellular antioxidant enzyme, detoxifying H 2 O 2 to oxygen and water. A significant increase in CAT production in the PC group was presumably the result of H 2 O 2 generation in response to hypoxia.…”