Vascular permeability disruption explored in the proteomes of mouse lungs and human microvascular cells following acute bromine exposure

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 319; no. 2; pp. L337 - L359
• Main Authors: Addis, Dylan R., Aggarwal, Saurabh, Doran, Stephen F., Jian, Ming-Yuan, Ahmad, Israr, Kojima, Kyoko, Ford, David A., Matalon, Sadis, Mobley, James A.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Physiological Society 01.08.2020
• Series: Translational Physiology
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00196.2020

Bromine (Br 2 ) is an organohalide found in nature and is integral to many manufacturing processes. Br 2 is toxic to living organisms, and high concentrations can prove fatal. To meet industrial demand, large amounts of purified Br 2 are produced, transported, and stored worldwide, providing a multitude of interfaces for potential human exposure through either accidents or terrorism. To identify the key mechanisms associated with acute Br 2 exposure, we have surveyed the lung proteomes of C57BL/6 male mice and human lung-derived microvascular endothelial cells (HMECs) at 24 h following exposure to Br 2 in concentrations likely to be encountered in the vicinity of industrial accidents. Global discovery proteomics applications combined with systems biology analysis identified robust and highly significant changes in proteins associated with three biological processes: 1) exosome secretion, 2) inflammation, and 3) vascular permeability. We focused on the latter, conducting physiological studies on isolated perfused lungs harvested from mice 24 h after Br 2 exposure. These experiments revealed significant increases in the filtration coefficient ( K f ) indicating increased permeability of the pulmonary vasculature. Similarly, confluent monolayers of Br 2 and Br-lipid-treated HMECs exhibited differential levels of zona occludens-1 that were found to be dissociated from cell wall localization, an increase in phosphorylation and internalization of E-cadherin, as well as increased actin stress fiber formation, all of which are consistent with increased permeability. Taken as a whole, our discovery proteomics and systems analysis workflow, combined with physiological measurements of permeability, revealed both profound and novel biological changes that contribute to our current understanding of Br 2 toxicity.