Distribution of PAI-1 promoter 4G/5G polymorphism in healthy Chinese and functional characterization using a luciferase reporter vector

The VA Hypertension Primary Care Longitudinal Cohort: Electronic medical records in the post-genomic era

The Veterans Affairs Hypertension Primary Care Longitudinal Cohort (VAHC) was initiated in 2003 as a pilot study designed to link the VA electronic medical record system with individual genetic data. Between June 2003 and December 2004, 1,527 hypertensive participants were recruited. Protected health information (PHI) was extracted from the regional VA data warehouse. Differences between the clinic and mail recruits suggested that clinic recruitment resulted in an over-sampling of African Americans. A review of medical records in a random sample of study participants confirmed that the data warehouse accurately captured most selected diagnoses. Genomic DNA was acquired non-invasively from buccal cells in mouthwash; ~ 96.5 per cent of samples contained DNA suitable for genotyping, with an average DNA yield of 5.02 ± 0.12 micrograms, enough for several thousand genotypes. The coupling of detailed medical databases with genetic information has the potential to facilitate the genetic study of hypertension and other complex diseases.

Failure to lyse venous thrombi because of elevated plasminogen activator Inhibitor 1 (PAI-1) and 4G polymorphism of its promotor genome (The PAI-1/4G Syndrome)

Plasminogen activator Inhibitor 1 (PAI-1) inhibits plasminogen activators leading to decreased fibrinolysis and increased risk of thromboembolic disease (TED). Shifts in PAI-1 promoter genome from normal 5G>5G to 4G>5G or 4G>4G alleles are associated with overexpression of PAI-1. In this study patients with residual venous thrombi were observed to have increased PAI-1 levels and more frequent shifts to 4G alleles. Of the 26, 20 (76.9%) patients with unresolved thrombus had elevated PAI-1 values. 4G genomic shifts were found in 92.9% patients studied. Normal PAI-1 levels were found in 5 patients with 4G polymorphisms. Thus, PAI-1 is often elevated among patients with residual thrombus, with an unexpectedly high prevalence of the 4G polymorphism of the promoter genome. Patients with persistent thrombus should be considered at risk of having constituently increased PAI-1 due to genomic changes in the PAI-1 promoter genome. Hypotheses are proposed to explain those with normal PAI-1, despite having 4G polymorphisms.

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

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.