Validation of Non-Electrophile Nrf2 Activators for WTC Relevant Pulmonary Indications

Details

• Personal Author:
  Cameron MD
• Description:
  Project initiation was slowed due to Covid19 initiated capacity restrictions. The planned in vivo experiments require multiple researchers to be present. Because of this we initially focused on Aim2. The lead Nrf2 activator was modified to incorporate an amide. The amide was used to couple photo-activated diazirine probes using a short and a long linker. These were evaluated and did not activate Nrf2. We used a backup strategy and developed a fluorescence polarization assay and examined the binding of the test compounds at the interface between Nrf2 and its binding partner Keap1. The compounds were found to bind to a unique binding site which opens up new areas to explore for the modulation of Nrf2 activity. As Covid19 restrictions were lifted, we initiated in vivo studies. The test compounds were shown to increase the mRNA levels of Nrf2 target genes in the lungs of mice and elevated the concentration of the key cellular antioxidant, glutathione. Tolerability and toxicity were not observed after dosing the test compounds. We proceeded to a bleomycin-induced lung injury model. Bleomycin intercalates into DNA and causes DNA double-strand breaks, culminating in high systemic toxicity three to seven days post-dose and severe pulmonary fibrotic injury within four weeks. The test compound has poor solubility and requires the use of micelle-based excipients to solubilize and dose the compound. These excipients proved to be incompatible with the bleomycin model. The use of alternative formulations and oral dosing were unsuccessful and resulted in minimal plasma levels of the test compound. With the limited remaining time on the one-year award, the compounds were tested in an asbestos model of lung injury where the formulation did not cause a problem. Pulmonary injury was evaluated four weeks after asbestos insult. We were surprised to see that when compared to control mice dosed with saline, asbestos upregulated the expression of Nrf2 target genes in lung tissue. The test compounds further increased the level of Nrf2 target genes in the asbestos-treated group. Objective markers of pulmonary function, cytokine levels, and fibrosis were measured. Pulmonary function was not observed to decline over the first 28 days. Mice treated with the non-electrophile Nrf2 activators had decreased levels of both pro-inflammatory cytokines and mRNA for collagen synthesis enzymes, but the change did not reach statistical significance. Due to the progressive nature of asbestos injury, the four-week study may have been too short, and evaluating the impact over three to six months may give a better indication of the potential of the Nrf2 activators to modulate pulmonary injury. [Description provided by NIOSH]
• Subjects:
  Biochemistry Genetics Lung Lung Diseases Occupational Health Respiratory System Respiratory Tract Diseases Safety September 11 Terrorist Attacks
• Keywords:
  Genes Genetic Testing Lung Fibrosis Oxidative Stress Pulmonary Effects Respiratory Irritants World Trade Center WTC
• Series:
  Grant Final Reports
• Publisher:
  National Institute for Occupational Safety and Health
• Document Type:
  Text
• Funding:
  Cooperative Agreement
• Genre:
  Final Cooperative Agreement Report
• Place as Subject:
  Florida ; OSHA Region 4
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  OEP - Office of Extramural Programs
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  1-7
• NIOSHTIC Number:
  nn:20066624
• Citation:
  Atlanta, GA: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, U01-OH-012054, 2022 Sep; :1-7
• Email:
  michaelcameron@ufl.edu
• Federal Fiscal Year:
  2022
• Performing Organization:
  Scripps Florida, Jupiter
• Peer Reviewed:
  False
• Start Date:
  20200701
• Source Full Name:
  National Institute for Occupational Safety and Health
• End Date:
  20210630
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:7fb94f2c6ecc5864d04310d9d873975df490eaba43586e596f3d3526d1665a58ac9fc7b16721ed28710cb9b8a1367d226e3a6285af0ffc2d75e804dfd282f557
• Download URL:
  https://stacks.cdc.gov/view/cdc/219164/cdc_219164_DS1.pdf
• File Type:
  [PDF - 210.21 KB ]