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Glutathionylation of Pyruvate Dehydrogenase Complex E2 Protein During Acute Inflammation Is Magnified By Mitochondrial Oxidative Stress, Enhancing Cell Death.

ABSTRACT: Lipopolysaccharide (LPS) is a known inducer of inflammatory signaling which triggers generation of reactive oxygen species (ROS) and cell death in responsive cells like THP-1 promonocytes and freshly isolated human monocytes. A key LPS-responsive metabolic pivot point is the 9.5 megadalton mitochondrial pyruvate dehydrogenase complex (PDC), which provides pyruvate dehydrogenase (E1), lipoamide-linked transacetylase (E2) and lipoamide dehydrogenase (E3) activities to produce acetyl-CoA from pyruvate. While phosphorylation-dependent decreases in PDC activity following LPS treatment or sepsis have been deeply investigated, redox-linked processes have received less attention. Data presented here demonstrate that LPS-induced reversible oxidation within PDC occurs in PDCE2 in both THP-1 cells and primary monocytes. Knockout of PDCE2 by CRISPR and expression of FLAG-tagged PDCE2 in THP-1 cells demonstrated that LPS-induced glutathionylation is associated with wild type PDCE2 but not mutant protein lacking the lipoamide-linking lysine residues. Moreover, the mitochondrially-targeted electrophile MitoCDNB elevates ROS similar to LPS but does not cause PDCE2 glutathionylation. However, both LPS and MitoCDNB together are synergistic for PDCE2 glutathionylation, ROS production, and cell death. These results suggest that glutathionylation on PDCE2 lipoamide sulfurs is a specific modification associated with LPS and cell death which is not recapitulated by a general rise in mitochondrial ROS, but is enhanced after LPS treatment by rising oxidative stress exerted by MitoCDNB that impairs reductase systems.

Highlights

PDCE2 is oxidized and glutathionylated (-SSG) during acute inflammation in monocytesPDCE2 knockout cells exhibit decreased ROS production during acute inflammationLipopolysaccharide-induced PDCE2-SSG occurs in THP1 cells and fresh monocytesLipoamide-deficient PDCE2 exhibits lower LPS-induced PDCE2-SSG and ROS productionMitoCDNB leads to ROS production but not PDCE2-SSG, but is synergistic with LPS.

SUBMITTER: Long DL

PROVIDER: S-EPMC9900926 | biostudies-literature | 2023 Jan

REPOSITORIES: biostudies-literature

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Glutathionylation of Pyruvate Dehydrogenase Complex E2 and Inflammatory Cytokine Production During Acute Inflammation Are Magnified By Mitochondrial Oxidative Stress.

Long David L DL McCall Charles E CE Poole Leslie B LB

bioRxiv : the preprint server for biology 20230804

Lipopolysaccharide (LPS) is a known inducer of inflammatory signaling which triggers generation of reactive oxygen species (ROS) and cell death in responsive cells like THP-1 promonocytes and freshly isolated human monocytes. A key LPS-responsive metabolic pivot point is the 9 megadalton mitochondrial pyruvate dehydrogenase complex (PDC), which provides pyruvate dehydrogenase (E1), lipoamide-linked transacetylase (E2) and lipoamide dehydrogenase (E3) activities to produce acetyl-CoA from pyruvat ...[more]

PMID: 36747682

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