Asthma is characterized by an oxidantantioxidant imbalance in the lungs leading to activation of redox-sensitive
transcription factors,
nuclear factor kappaB (
NF-kappaB), and
activator protein-1 (AP-1). To develop therapeutic strategies for
asthma, we used a chemogenomics approach to screen for small molecule inhibitor(s) of
AP-1 transcription. We developed a beta-strand mimetic template that acts as a reversible inhibitor (pseudosubstrate) of redox
proteins. This template incorporates an enedione moiety to trap reactive
cysteine nucleophiles in the active sites of redox
proteins. Specificity for individual redox factors was achieved through variations in X and Y functionality by using a combinatorial library approach. A limited array (2 x 6) was constructed where X was either NHCH(3) or NHCH(2) Ph and Y was methyl, phenyl, m-cyanophenyl, m-nitrophenyl, m-acetylaniline, or m-methylbenzoate. These analogs were evaluated for their ability to inhibit transcription in transiently transfected human lung epithelial A549 cells from either an
AP-1 or
NF-kappaB reporter. A small-molecule inhibitor,
PNRI-299, was identified that selectively inhibited
AP-1 transcription (IC(50) of 20 microM) without affecting
NF-kappaB transcription (up to 200 microM) or
thioredoxin (up to 200 microM). The molecular target of
PNRI-299 was determined to be the
oxidoreductase, redox effector factor-1 by an affinity chromatography approach. The selective redox effector factor-1 inhibitor,
PNRI-299, significantly reduced airway eosinophil infiltration, mucus hypersecretion,
edema, and
IL-4 levels in a mouse
asthma model. These data validate
AP-1 as an important therapeutic target in allergic airway
inflammation.