Binding of upstream stimulatory factor 1 to the E-Box regulates the 4G/5G polymorphism-dependent plasminogen activator inhibitor 1 expression in mast cells

Zhongcai Ma, Bong Sook Jhun, Sandy Y. Jung, Chad K. Oh

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Background: Plasminogen activator inhibitor (PAI)-1 is a key regulator of the fibrinolytic system. PAI-1 levels are markedly elevated in the asthmatic airways. The 4G/5G polymorphism of the PAI-1 gene is associated with allergic asthma. Objective: To characterize the mechanisms of the 4G/5G-dependent PAI-1 expression in mast cells (MCs), a major source of PAI-1 and key effector cells in asthma. Methods: Transcription of PAI-1 was assessed by transiently transfecting human MC line (HMC-1) cells with the luciferase-tagged PAI-1 promoters containing the 4G or 5G allele (4G-PAI-1 or 5G-PAI-1 promoter). Upstream stimulatory factor (USF)-1 and the E-box interactions were studied by electrophoretic mobility shift assays and supershift assays. Expression of USF-1 was determined by Western blot analysis. Results: The 4G-PAI-1 promoter has higher promoter activity than the 5G-PAI-1 promoter in stimulated HMC-1 cells, and the E-box adjacent to the 4G/5G site (E-4G/5G) regulates the genotype-specific PAI-1 transcription. USF-1 binds to the E-4G with greater affinity than to the E-5G. USF-1 level is increased in HMC-1 cells after stimulation, and elevated USF-1 enhances PAI-1 transcription. Overexpression of wild-type USF-1 or dominant-negative USF remedies the 4G/5G-dependent PAI-1 transcription. Conclusion: Binding of USF-1 to the E-4G/5G regulates the 4G/5G polymorphism-dependent PAI-1 expression in MCs.

Original languageEnglish (US)
Pages (from-to)1006-1012.e2
JournalJournal of Allergy and Clinical Immunology
Volume121
Issue number4
DOIs
StatePublished - Apr 2008
Externally publishedYes

Keywords

  • 4G/5G polymorphism
  • E-box
  • Plasminogen activator inhibitor 1
  • human mast cells
  • transcription
  • upstream stimulatory factor 1

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