title: Induction of heme oxygenase I (HMOX1) by HPP-4382: a novel modulator of Bach1 activity.
abstract: Oxidative stress is generated by reactive oxygen species (ROS) produced in response to metabolic activity and environmental factors. Increased oxidative stress is associated with the pathophysiology of a broad spectrum of inflammatory diseases. Cellular response to excess ROS involves the induction of antioxidant response element (ARE) genes under control of the transcriptional activator Nrf2 and the transcriptional repressor Bach1. The development of synthetic small molecules that activate the protective anti-oxidant response network is of major therapeutic interest. Traditional small molecules targeting ARE-regulated gene activation (e.g., bardoxolone, dimethyl fumarate) function by alkylating numerous proteins including Keap1, the controlling protein of Nrf2. An alternative is to target the repressor Bach1. Bach1 has an endogenous ligand, heme, that inhibits Bach1 binding to ARE, thus allowing Nrf2-mediated gene expression including that of heme-oxygenase-1 (HMOX1), a well described target of Bach1 repression. In this report, normal human lung fibroblasts were used to screen a collection of synthetic small molecules for their ability to induce HMOX1. A class of HMOX1-inducing compounds, represented by HPP-4382, was discovered. These compounds are not reactive electrophiles, are not suppressed by N-acetyl cysteine, and do not perturb either ROS or cellular glutathione. Using RNAi, we further demonstrate that HPP-4382 induces HMOX1 in an Nrf2-dependent manner. Chromatin immunoprecipitation verified that HPP-4382 treatment of NHLF cells reciprocally coordinated a decrease in binding of Bach1 and an increase of Nrf2 binding to the HMOX1 E2 enhancer. Finally we show that HPP-4382 can inhibit Bach1 activity in a reporter assay that measures transcription driven by the human HMOX1 E2 enhancer. Our results suggest that HPP-4382 is a novel activator of the antioxidant response through the modulation of Bach1 binding to the ARE binding site of target genes.
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Otis C
authors.initials: OC
authors.lastname: Attucks
authors.affiliation: Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Kimberly J
authors.initials: KJ
authors.lastname: Jasmer
authors.affiliation: Biochemistry Department and Life Sciences Center, University of Missouri, Columbia, Missouri, United States of America.
authors.forename: Mark
authors.initials: M
authors.lastname: Hannink
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Jareer
authors.initials: J
authors.lastname: Kassis
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Zhenping
authors.initials: Z
authors.lastname: Zhong
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Suparna
authors.initials: S
authors.lastname: Gupta
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Sam F
authors.initials: SF
authors.lastname: Victory
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Mustafa
authors.initials: M
authors.lastname: Guzel
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Dharma Rao
authors.initials: DR
authors.lastname: Polisetti
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Robert
authors.initials: R
authors.lastname: Andrews
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Adnan M M
authors.initials: AM
authors.lastname: Mjalli
authors.affiliation: TransTech Pharma LLC, High Point, North Carolina, United States of America.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kostura
mesh_terms: D061745:Antioxidant Response Elements; D050976:Basic-Leucine Zipper Transcription Factors / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D047369:Chromatin Immunoprecipitation; D051856:Fanconi Anemia Complementation Group Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects; D006418:Heme / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D018384:Oxidative Stress; D015533:Transcriptional Activation
chemical_list: C102108:BACH1 protein, human; D050976:Basic-Leucine Zipper Transcription Factors; D051856:Fanconi Anemia Complementation Group Proteins; D006418:Heme; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1