C-C chemokine ligand 2 gene expression in nasal polyp fibroblasts: possible implication in the pathogenesis of nasal polyposis.
OBJECTIVE
Recruitment of macrophages is essential to the pathogenesis of nasal polyps (NP), since this disease is inflammation-related. In this study, the effects of tumor necrosis factor alpha (TNF-alpha) on the expression of C-C chemokine ligand 2 (CCL2) in fibroblasts derived from nasal polyps (NPFs) were investigated. The roles of cyclooxygenase (COX) 2 and prostaglandins in the mediation of TNF-alpha-stimulated CCL2 gene expression were also investigated.


METHODS
Northern blot analysis was used to study the expression of CCL2 and c-Fos in cultured NPFs. An electrophoretic mobility shift assay was used to explore the interactions between activator protein 1 (AP- 1) and DNA. Immunohistochemistry was used to explore the in vivo expressions of COX-2, CCL2, and CD68 in NPs.


RESULTS
The Northern blot analysis showed that TNF-alpha stimulated the expression of CCL2 and COX-2 genes, and the synthesis of CCL2 messenger RNA was COX-2-dependent. A transient elevation of c-Fos and c-Jun messenger RNAs was induced by TNF-alpha, whereas COX-2 inhibitors NS-398 and meloxicam abolished the up-regulation of c-Fos. The electrophoretic mobility shift assay revealed that TNF-alpha triggered AP-1 and DNA binding and again, NS-398 and meloxicam inhibited this reaction via reducing c-Fos synthesis. Curcumin (AP-1 inhibitor) markedly suppressed the TNF-alpha-induced CCL2 expression. The immunohistochemical staining of NP surgical specimens also revealed an intimate alignment between CCL2-positive fibroblasts and CD-68-positive macrophages.


CONCLUSIONS
These data suggest that NPFs may contribute to NP development by synthesizing CCL2 to promote macrophage recruitment. Furthermore, COX-2 facilitates CCL2 transcription in NPFs via a c-Fos and AP-1 signaling pathway.
Shun
Chia-Tung
CT
Dept of Otolaryngology, National Taiwan University Hospital, 1 Chang-Teh Street, Taipei, Taiwan.
Lin
Sze-Kwan
SK
Hong
Chi-Yuan
CY
Kok
Sang-Heng
SH
Juan
Yun-Hsiang
YH
Wang
Chih-Chiang
CC
Hsu
Ming-Che
MC
Liu
Chia-Ming
CM
D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis* / Q000235:genetics*; D051546:Cyclooxygenase 2 / Q000502:physiology; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D009298:Nasal Polyps / Q000209:etiology*; D011453:Prostaglandins / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology
C111835:CCL2 protein, human; D018932:Chemokine CCL2; D011453:Prostaglandins; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2