Mitochondrial-mediated Lung Injury mechanisms of QACs in vivo

题目：线粒体介导的QACs肺损伤机制

Title: Mitochondrial-mediated Lung Injury mechanisms of QACs in vivo Project Summary/Abstract Quaternary ammonium salts (QACs) such as benzalkonium chloride (BAC) and dimethyldidecylammonium chloride (DDAC) are widely used in many disinfectants and cleaners, and it is likely that more than 1 million Americans get exposed to BAC/DDAC on a daily basis. Although QACs have been considered safe, and were 'grandfathered' into US regulatory system in 1960s, our recent pilot human exposure data demonstrate that QACs such as BAC/DDAC are present in human plasma in 1/3rd of sample population at the range of 10-150 nM which is greater than the US Environmental Protection agency's `actionable' level for internal exposure. Our pilot human exposure study further shows that the presence of QACs in human blood strongly correlates with decreased maximal mitochondrial respiration in WBCs. Our previous and ongoing in vitro studies show that QACs such as BACs inhibit mitochondrial function and suppress estrogen signaling in the 100 - 10,000 nM (0.000004% - 0.0004% w/w) range, and this concentration range overlaps the 10-150 nM plasma levels of QACs in humans showing mitochondrial toxicity. Based on our studies California Department of Public Health has listed QACs as priority chemicals for biomonitoring purposes. During the current COVID19 pandemic, usage of QAC-based disinfectants has increased many fold and most of these disinfectants are applied through atomizers and sprays suggesting a potential aerosolized inhalation exposure to humans. Although clinical studies have demonstrated that exposure to QACs can cause bronchoconstriction and lung injury, the cellular targets and the molecular mechanisms are currently unknown. This application explores the systemic absorption through inhalation in an animal model, establishes a dose-dependent mitochondrial inhibition in vivo and elucidate the molecular mechanism and cellular targets for QAC-induced lung injury. Aim 1 is a concentration-response study of systemic BAC/DDAC mitochondrial inhibition in vivo and elucidation of molecular mechanism of lung injury. Aim 2 will evaluate the magnitude of QAC-induced pulmonary toxicity and elucidate the cellular targets in vivo. Aim 3 will develop a reliable method to detect QACs in biological matrices and measure BAC/DDAC levels in inhalation-dosed animal tissues. The completion of these studies will determine whether BAC/DDAC can get absorbed systematically through inhalation and are mitochondrial toxins in vivo, and whether mitochondrial inhibitory property of BAC/DDAC is responsible for their pulmonary toxicity All of these could ultimately support more educated decision making about the relative range of QAC exposure that may be safe in humans.