ERK1/2 and p38 regulate inter-individual variability in ozone-mediated IL-8 gene expression in primary human bronchial epithelial cells

Abstract

Inter-individual variability is observed in all biological responses; however this variability is difficult to model and its underlying mechanisms are often poorly understood. This issue currently impedes understanding the health effects of the air pollutant ozone. Ozone produces pulmonary inflammation that is highly variable between individuals; but reproducible within a single individual, indicating undefined susceptibility factors. Studying inter-individual variability is difficult with common experimental models, thus we used primary human bronchial epithelial cells (phBECs) collected from many different donors. These cells were cultured, exposed to ozone, and the gene expression of the pro-inflammatory cytokine IL-8 was measured. Similar to in vivo observations, we found that ozone-mediated IL-8 expression was variable between donors, but reproducible within a given donor. Recent evidence suggests that the MAP kinases ERK1/2 and p38 mediate ozone-induced IL-8 transcription, thus we hypothesized that differences in their activation may control IL-8 inter-individual variability. We observed a significant correlation between ERK1/2 phosphorylation and IL-8 expression, suggesting that ERK1/2 modulates the ozone-mediated IL-8 response; however, we found that simultaneous inhibition of both kinases was required to achieve the greatest IL-8 inhibition. We proposed a “dimmer switch” model to explain how the coordinate activity of these kinases regulate differential IL-8 induction.

<p>Dual Role For A MEK Inhibitor As A Modulator Of Inflammation And Host Defense Mechanisms With Potential Therapeutic Application In COPD</p>

“…An explanation for the ceiling effect could be due to the "shunting" effect when p38 inhibitors are utilized in this assay system at the level of MAPK phosphorylation. This cross-talk or shunting between the ERK and p38 pathways have been previously reported in osteosarcoma cells, 47 PC12 cells, 48 bronchial epithelial cells 49 and in corneal epithelial cells. 50 In corneal epithelial cells and osteosarcoma cells, it was reported that inhibition of either one of the MAPK pathways could result in the activation of the other.…”

Comparison of the basic morphology and function of 3D lung epithelial cultures derived from several donors

“…Our observations are aligned with those of previous studies using ALI lung models, showing preserved responses to certain stimuli across donors despite variations in intensity. For instance, the secretion profile of proinflammatory mediators ( Banerjee et al, 2017 ) and the changes in gene expression in response to cigarette smoke exposure ( Haswell et al, 2017 ; Iskandar et al, 2017b ) as well as the inflammatory response following ozone exposure ( Bowers et al, 2018 ) followed similar patterns across cultures from different donors, although they varied in magnitude. In contrast, the inflammatory response of airway cultures to influenza virus infection seems to be more impacted by the donor of the cultures ( Ilyushina et al, 2019 ), which suggests that interdonor variability should be specifically addressed for each endpoint and experimental condition tested.…”

LINE-1 Cargo and Reverse Transcriptase Activity Profiles in Extracellular Vesicles from Lung Cancer Cells and Human Plasma

“…Cells and EVs were lysed in RIPA buffer and subjected to Western blotting as previously described [ 36 ], with modifications as noted for ORF2p. Immunoblots were imaged using a Konica Minolta SRX101A film developer and the Licor Odyssey FC Imaging System (LI-COR Biosciences, Lincoln, Nebraska, USA).…”