The development of nasal polyps involves early middle meatus mucous remodeling via TGF-β1 mediated PAI-1 reduction()

OBJECTIVE: Our study aimed to elucidate the effect of PAI-1 (Plasminogen Activator Inhibitor-1) and t-PA (Tissue-type Plasminogen Activator) in tissue remodeling in nasal polyps patients. METHODS: Samples were streamed as early Nasal Polyps (eNP, n = 10) and inferior tissue from the same patient, mature Nasal Polyps (mNP, n = 14), and Control group (n = 15), respectively. Immunohistochemistry and immunofluorescence were applied to detect localization. Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and Western blot were used to measure different levels among three groups. The mNP tissue was cultured in vitro and treated with TGF-β1 (Transforming Growth Factor-beta 1) activator, TGF-β1 inhibitor (SB431542), and PAI-1 inhibitor (TM5275); then Western blot, qRT-PCR, and ELISA were used to assess changes. RESULTS: The immunohistochemistry and immunofluorescence showed that PAI-1 expression decreased in eNP and mNP, mainly in epithelium and glands. The transcriptional expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 were lower in eNP than IT while mNP group demonstrated lower mRNA expression and protein level of TGF-β1/t-PA/PAI-1/Collagen1 than Control group. In mNP tissue culture in vitro, TGF-β1 activator elevated t-PA, PAI-1, and Collagen1 with higher release of PAI-1 and Collagen1 in supernatant, whereas SB431542 suppressed above reactions; TM5275 lowered transcriptional and protein level of Collagen1 in supernatant. CONCLUSION: Early Nasal polyps’ formation in middle meatus mucous is related with fibrillation system PAI-1/t-PA and tissue remodeling; moreover, nasal polyps’ development is regulated by TGF-β1-mediated PAI-1 reduction. LEVEL OF EVIDENCE: 3b.