Chlorinated lipids in sepsis

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Sepsis is a major cause of morbidity and mortality in both adults and children with >1.6 million cases per year in the United States. Neutrophils are key early responders to infection. Neutrophils eliminate microbes by phagocytosis and by oxidant-mediated killing. Neutrophil myeloperoxidase (MPO) produces the potent oxidant, hypochlorous acid (HOCl), which reacts with both microbial and host molecular targets including lipids. PI Dr. David Ford has shown HOCl targets the vinyl ether bond of plasmalogen lipids, resulting in the production of 2- chlorofatty aldehyde (2-ClFALD) and other chlorolipids, including 2-chlorofatty acid (2-ClFA), in response to leukocyte activation. This led our multi-PI team during the previous grant interval to determine chlorolipids elicit endothelial activation leading to leukocyte and platelet adherence, and to demonstrate chlorolipids associate with ARDS and 30-day mortality in human sepsis. Our multi-PI group has accrued new preliminary data showing that: 1) 2-ClFA modifies specific endothelial cell proteins, which may represent a new paradigm to target for intervention of 2-ClFA-caused endothelial activation; 2) plasma levels of w-oxidation products of 2- ClFA, 2-chlorodicarboxylic acids (2-ClDCAs), measured on admission to the intensive care unit (ICU) with sepsis are elevated in patients that develop acute kidney injury (AKI); and 3) 2-ClDCA causes endothelial dysfunction. The role of chlorolipids in sepsis is expanding, and these preliminary data indicate there are knowledge gaps that need to be addressed in the proposed studies, which will test our overall hypothesis that chlorolipids produced by activated neutrophils during sepsis are mediators of severe endothelial dysfunction resulting in multiple organ failure. There are two specific aims. Specific Aim 1 will test the hypothesis that chlorolipid-mediated dysfunction in human endothelial cells can be pharmacologically targeted. Specific Aim 2 will test the hypothesis that plasma 2-ClDCA levels associate with specific organ dysfunctions and death in human sepsis. Overall, a multi-disciplinary approach with our multi-PI team and Co-Is will examine chlorolipids produced by activated neutrophils during sepsis as critical mediators of microcirculatory dysfunction leading to organ failure, and test inhibitors of, and pathways activated by, chlorolipid-elicited endothelial dysfunction as intervention points. This collaborative investigation has the potential to provide new therapeutic and diagnostic targets for patients with sepsis.