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Growth of human bronchial epithelial cells at an air-liquid interface alters the response to particle exposure.

Ghio AJ, Dailey LA, Soukup JM, Stonehuerner J, Richards JH, Devlin RB - Part Fibre Toxicol (2013)

Bottom Line: Subsequently, it was not possible to attribute the observed decreases in the response of NHBE cells to differentiation alone since BEAS-2B cells, which do not differentiate, showed similar changes when grown at ALI.We conclude that growth of NHBE cells at ALI is associated with a diminished biological effect following particle exposure relative to cells submerged in media.This decreased response showed an association with increased oxygen availability.

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ABSTRACT

Background: We tested the hypothesis that normal human bronchial epithelial (NHBE) cells 1) grown submerged in media and 2) allowed to differentiate at air-liquid interface (ALI) demonstrate disparities in the response to particle exposure.

Results: Following exposure of submerged NHBE cells to ambient air pollution particle collected in Chapel Hill, NC, RNA for IL-8, IL-6, heme oxygenase 1 (HOX1) and cyclooxygenase 2 (COX2) increased. The same cells allowed to differentiate over 3, 10, and 21 days at ALI demonstrated no such changes following particle exposure. Similarly, BEAS-2B cells grown submerged in media demonstrated a significant increase in IL-8 and HOX1 RNA after exposure to NIST 1648 particle relative to the same cells exposed after growth at ALI. Subsequently, it was not possible to attribute the observed decreases in the response of NHBE cells to differentiation alone since BEAS-2B cells, which do not differentiate, showed similar changes when grown at ALI. With no exposure to particles, differentiation of NHBE cells at ALI over 3 to 21 days demonstrated significant decrements in baseline levels of RNA for the same proteins (i.e. IL-8, IL-6, HOX1, and COX2). With no exposure to particles, BEAS-2B cells grown at ALI showed comparable changes in RNA for IL-8 and HOX1. After the same particle exposure, NHBE cells grown at ALI on a transwell in 95% N2-5% CO2 and exposed to NIST 1648 particle demonstrated significantly greater changes in IL-8 and HOX1 relative to cells grown in 95% air-5% CO2.

Conclusions: We conclude that growth of NHBE cells at ALI is associated with a diminished biological effect following particle exposure relative to cells submerged in media. This decreased response showed an association with increased oxygen availability.

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Fold change RNA of BEAS-2B cells for IL-8 (A) and HOX1 (B) following exposure to 250 μg NIST 1648. There were significant increases in RNA after exposure of submerged cells only. In contrast, no increased RNA was observed following exposure of BEAS-2B cells grown at ALI to the same particle. *Significant increase relative to RNA in unexposed BEAS-2B cells.
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Figure 2: Fold change RNA of BEAS-2B cells for IL-8 (A) and HOX1 (B) following exposure to 250 μg NIST 1648. There were significant increases in RNA after exposure of submerged cells only. In contrast, no increased RNA was observed following exposure of BEAS-2B cells grown at ALI to the same particle. *Significant increase relative to RNA in unexposed BEAS-2B cells.

Mentions: To evaluate the role of differentiation in changes of PM response, BEAS-2B cells were employed; these cells do not differentiate. BEAS-2B cells grown for 21 days on the transwell continued to proliferate. The cells retained a cobblestone appearance but the cellular density increased with heaping or stacking evident. Submerged BEAS-2B cells demonstrated a significant increase in IL-8 and HOX1 RNA after 4 hour exposure to NIST 1648 particle (Figures 2A and2B). However, the same cells grown at ALI and exposed to the same particle showed no change in IL-8 and HOX1 RNA comparable to the response of the NHBE cells (Figures 2A and2B).


Growth of human bronchial epithelial cells at an air-liquid interface alters the response to particle exposure.

Ghio AJ, Dailey LA, Soukup JM, Stonehuerner J, Richards JH, Devlin RB - Part Fibre Toxicol (2013)

Fold change RNA of BEAS-2B cells for IL-8 (A) and HOX1 (B) following exposure to 250 μg NIST 1648. There were significant increases in RNA after exposure of submerged cells only. In contrast, no increased RNA was observed following exposure of BEAS-2B cells grown at ALI to the same particle. *Significant increase relative to RNA in unexposed BEAS-2B cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3750262&req=5

Figure 2: Fold change RNA of BEAS-2B cells for IL-8 (A) and HOX1 (B) following exposure to 250 μg NIST 1648. There were significant increases in RNA after exposure of submerged cells only. In contrast, no increased RNA was observed following exposure of BEAS-2B cells grown at ALI to the same particle. *Significant increase relative to RNA in unexposed BEAS-2B cells.
Mentions: To evaluate the role of differentiation in changes of PM response, BEAS-2B cells were employed; these cells do not differentiate. BEAS-2B cells grown for 21 days on the transwell continued to proliferate. The cells retained a cobblestone appearance but the cellular density increased with heaping or stacking evident. Submerged BEAS-2B cells demonstrated a significant increase in IL-8 and HOX1 RNA after 4 hour exposure to NIST 1648 particle (Figures 2A and2B). However, the same cells grown at ALI and exposed to the same particle showed no change in IL-8 and HOX1 RNA comparable to the response of the NHBE cells (Figures 2A and2B).

Bottom Line: Subsequently, it was not possible to attribute the observed decreases in the response of NHBE cells to differentiation alone since BEAS-2B cells, which do not differentiate, showed similar changes when grown at ALI.We conclude that growth of NHBE cells at ALI is associated with a diminished biological effect following particle exposure relative to cells submerged in media.This decreased response showed an association with increased oxygen availability.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: We tested the hypothesis that normal human bronchial epithelial (NHBE) cells 1) grown submerged in media and 2) allowed to differentiate at air-liquid interface (ALI) demonstrate disparities in the response to particle exposure.

Results: Following exposure of submerged NHBE cells to ambient air pollution particle collected in Chapel Hill, NC, RNA for IL-8, IL-6, heme oxygenase 1 (HOX1) and cyclooxygenase 2 (COX2) increased. The same cells allowed to differentiate over 3, 10, and 21 days at ALI demonstrated no such changes following particle exposure. Similarly, BEAS-2B cells grown submerged in media demonstrated a significant increase in IL-8 and HOX1 RNA after exposure to NIST 1648 particle relative to the same cells exposed after growth at ALI. Subsequently, it was not possible to attribute the observed decreases in the response of NHBE cells to differentiation alone since BEAS-2B cells, which do not differentiate, showed similar changes when grown at ALI. With no exposure to particles, differentiation of NHBE cells at ALI over 3 to 21 days demonstrated significant decrements in baseline levels of RNA for the same proteins (i.e. IL-8, IL-6, HOX1, and COX2). With no exposure to particles, BEAS-2B cells grown at ALI showed comparable changes in RNA for IL-8 and HOX1. After the same particle exposure, NHBE cells grown at ALI on a transwell in 95% N2-5% CO2 and exposed to NIST 1648 particle demonstrated significantly greater changes in IL-8 and HOX1 relative to cells grown in 95% air-5% CO2.

Conclusions: We conclude that growth of NHBE cells at ALI is associated with a diminished biological effect following particle exposure relative to cells submerged in media. This decreased response showed an association with increased oxygen availability.

Show MeSH
Related in: MedlinePlus