P-glycoprotein functions as an immunomodulator in healthy human primary nasal epithelial cells.

Abstract

BACKGROUND:

P-glycoprotein (P-gp) is an adenosine triphosphate (ATP)-dependent efflux pump that confers chemotherapeutic resistance in cancer cells. Recent studies suggest that P-gp may also function as an immunomodulator through regulation of cytokine transport. Sinonasal epithelial cells have been recognized as drivers of local innate and adaptive immunity and are known to overexpress P-gp in the setting of inflammation. The objective of this study is to therefore determine whether P-gp participates in the regulation of cytokine secretion in sinonasal epithelial cells.

METHODS:

Primary nasal epithelial cell cultures (PNECCs) were cultivated from 5 healthy patients. Membranous P-gp was quantified through quantitative fluorescent immunohistochemistry (Q-FIHC) and confirmed by enzyme-linked immunosorbent assay (ELISA). Sensitivity to inhibition was determined using a rhodamine 123 accumulation assay. Baseline and lipopolysaccharide (LPS)-stimulated cytokine secretion of interleukin 6 (IL-6), IL-8, granulocyte macrophage colony stimulating factor (GM-CSF), and thymic stromal lymphopoietin (TSLP) were quantified by ELISA and compared to LPS stimulated secretion in the setting of P-gp-specific inhibition. Differences in P-gp expression and cytokine secretion were compared using 2-tailed Student t tests with post hoc testing using the Bonferroni procedure.

RESULTS:

Membranous P-gp is detectable in PNECCs and upregulated following LPS exposure. P-gp is sensitive to inhibition by both PSC 833 and verapamil in a dose-dependent fashion. LPS stimulated secretion of normalized IL-6 (mean, 95% confidence interval [CI]) (79.67, 42.26-117.07), GM-CSF (39.92, 7.90-71.94), and TSLP (6.65, 5.35-7.96) was significantly reduced following P-gp inhibition (37.60, 11.54-63.65, p = 0.023; 7.64, 2.25-13.03, p = 0.044; and 5.13, 4.44-5.82, p = 0.038; respectively).

CONCLUSION:

P-gp is functionally active in PNECCs. P-gp participates in modulation of epithelial secretion of LPS stimulated IL-6, GM-CSF, and TSLP.

• Authors: Benjamin S Bleier, Angela L Nocera, Hufsa Iqbal, John D Hoang, Rachel E Feldman, Xue Han
• Journal: International forum of allergy & rhinology (Int Forum Allergy Rhinol) Vol. 3 Issue 6 Pg. 433-8 (Jun 2013) ISSN: 2042-6984 [Electronic] United States
• PMID: 23520057 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2013 ARS-AAOA, LLC.

Chemical References

• ATP Binding Cassette Transporter, Subfamily B, Member 1
• Cytokines
• Fluorescent Dyes
• Interleukin-6
• Interleukin-8
• Lipopolysaccharides
• Rhodamine 123
• Granulocyte-Macrophage Colony-Stimulating Factor
• Verapamil
• Thymic Stromal Lymphopoietin

Topics

• ATP Binding Cassette Transporter, Subfamily B, Member 1 (antagonists & inhibitors, metabolism)
• Cytokines (metabolism)
• Enzyme-Linked Immunosorbent Assay
• Epithelial Cells (metabolism)
• Fluorescent Dyes
• Granulocyte-Macrophage Colony-Stimulating Factor (metabolism)
• Humans
• Interleukin-6 (metabolism)
• Interleukin-8 (metabolism)
• Lipopolysaccharides (pharmacology)
• Nasal Cavity (metabolism)
• Rhodamine 123
• Verapamil (pharmacology)
• Thymic Stromal Lymphopoietin