Expression of SPLUNC1 protein in nasal polyp epithelial cells in air-liquid interface culture treated with IL-13.
BACKGROUND
Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) protein is an airway epithelial cell-derived molecule exerting host defense against pathogen. However, the function and regulation of SPLUNC1 in nasal epithelial cells are still unclear. Chronic rhinosinusitis with nasal polyps (CRSwNPs) is a disorder characterized by eosinophilic Th2 inflammation and frequent microbial colonization. The pathogenesis has been postulated as a disturbed mucosal immune response. This study investigates the SPLUNC1 expression of nasal polyp epithelial cells in air-liquid interface (ALI) culture and after treating with Th2 inflammatory cytokines IL-13.


METHODS
Human nasal polyp epithelial cells isolated from patients with CRSwNPs were put in different cell culture models at days 0 and 21 and were assessed for expression of SPLUNC1 by microarray. Cultured cells in ALI plus retinoic acid (ALI + RA) model were then incubated with 0, 1, 10, and 100 ng/mL human recombinant IL-13 for up to 5 days. The expression of SPLUNC1 was assessed by real-time quantitative polymerase chain reaction (RT-Q-PCR), reverse-transcriptase PCR (RT-PCR) and Western blot analysis.


RESULTS
ALI + RA culture model harvesting ciliary differentiated nasal epithelial cells constitutively expressed high levels of SPLUNC1. In contrast, SPLUNC1 is reduced under classic submerged single layer culture. SPLUNC1 is also dose-responsively down-regulated after incubation with IL-13.


CONCLUSIONS
A microenvironmental milieu containing IL-13 may be detrimental to the host innate immunity response, at least in part, through the inhibition of SPLUNC1 production.
Yeh
Te-Huei
TH
Department of Otolaryngology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei, Taiwan. tehueiyeh@ntu.edu.tw
Lee
Shiann-Yann
SY
Hsu
Wei-Chung
WC
D018929:Cell Culture Techniques; D002478:Cells, Cultured; D002908:Chronic Disease; D004306:Dose-Response Relationship, Immunologic; D015536:Down-Regulation; D004847:Epithelial Cells / Q000187:drug effects / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D006801:Humans; D018793:Interleukin-13 / Q000494:pharmacology*; D046228:Microarray Analysis; D009298:Nasal Polyps / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010750:Phosphoproteins / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D012220:Rhinitis / Q000276:immunology*; D012852:Sinusitis / Q000276:immunology*; D014212:Tretinoin / Q000378:metabolism
C485599:BPIFA1 protein, human; D006023:Glycoproteins; D018793:Interleukin-13; D010750:Phosphoproteins; D014212:Tretinoin