Glutathione can occur in reduced (GSH), oxidized (GSSG), or in mixed disulfide forms and is ubiquitous in multiple biological systems serving as the major thiol-disulfide redox buffer of the cell. GSSG is the oxidized form of GSH . It can be reduced back to GSH through the NADPH-dependent enzyme glutathione reductase. GSSG functions as a hydrogen acceptor in the enzymatic determination of NADP+ and NADPH and can be a proximal donor in S-glutathionylation post translational modifications. The ratio of reduced glutathione to oxidizedglutathione within cells is often used as an indicator of oxidative stress, with higher concentrations of GSSG predicting increased oxidative stress.
Ethoxyquin dimer is an antioxidant and metabolite of ethoxyquin .1 It prevents oxidation of polyunsaturated fatty acids in fish meal and fish oil. Dietary administration of ethoxyquin dimer (0.1, 0.3, and 0.5% w/w) induces microvesicular steatosis and hepatocyte necrosis, as well as increases liver levels of oxidizedglutathione and total lipids in mice.2
Peroxidation of common ω-6 polyunsaturated fatty acids (PUFAs) such as linoleic acid, DGLA, and arachidonic acid can give rise to 4-HNE. 4-HNE is cleared rapidly from the plasma and undergoes enterohepatic circulation as a glutathione conjugate in the rat. About two thirds of an administered dose of 4-HNE is excreted within 48 hours in the urine, primarily in the form of mercapturic acid conjugates. The C-1 aldehyde of 4-HNE is reduced to an alcohol in about half of these metabolites. The remainder are C-1 aldehydes or have been oxidized to C-1 carboxylic acids. These aldehydes and carboxylic acids can also form γ-lactols and γ-lactones, respectively, producing at least 4 or 5 end urinary metabolites of 4-HNE in vivo.
QD-394 is an inducer of reactive oxygen species (ROS) production.1It induces lipid peroxidation, increases in intracellular accumulation of reactive oxygen species (ROS), and decreases in the reduced glutathione (GSH) to oxidized GSH (GSSG) ratio in MIA PaCa-2 pancreatic cancer cells when used at concentrations ranging from 0.5 to 10 μM. QD-394 is cytotoxic to MIA PaCa-2, PANC-1, and BxPC-3 cancer cells (IC50s = 0.64, 0.34, and 0.9 μM, respectively). QD-394 acts synergistically with napabucasin to reduce colony formation in MIA PaCa-2 cells. 1.Hu, S., Sechi, M., Singh, P.K., et al.A novel redox modulator induces a GPX4-mediated cell death that is dependent on iron and reactive oxygen speciesJ. Med. Chem.63(17)9838-9855(2020)
Protectin conjugates in tissue regeneration 1 (PCTR1) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid . DHA is oxidized to 16S,17S-epoxy-protectin, which is then converted to PCTR1 by glutathione S-transferase. PCTR1 levels increase during resolution of acute microbial-induced peritonitis in mice. PCTR1 (30 ng, i.p.) administration 12 hours post-infection increases macrophage numbers and activity and shortens the resolution phase of inflammation by 57%. It also reduces the levels of PGE2 , PGD2 , and TXB2 in peritoneal exudates.
Protein conjugates in tissue regeneration 2 (PCTR2) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid . DHA is oxidized to 16S,17S-epoxy-protectin, which is converted to PCTR1 by glutathione S-transferase and to PCTR2 via γ-glutamyl transpeptidase. PCTR2 is found in resolving mouse exudate and in both M1 and M2 macrophages differentiated from isolated human monocytes.
Protein conjugates in tissue regeneration 3 (PCTR3) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid . DHA is oxidized to 16S,17S-epoxy-protectin, which is converted to PCTR1 by glutathione S-transferase and to PCTR2 and PCTR3 via peptidases. PCTR3 is found in infected mouse spleens and resolving exudate as well as isolated human spleen and septic plasma. It is also found in both M1 and M2 macrophages differentiated from isolated human monocytes.
Maresin conjugates in tissue regeneration 1 (MCTR1) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid in macrophages at the site of inflammation. DHA is oxidized to maresin 1 , which is then converted to MCTR1 by glutathione S-transferase Mu 4 or leukotriene C4 synthase. MCTR1 accelerates tissue regeneration in planaria (1 and 100 nM). Pretreatment with MCTR1 (50 ng mouse, i.p.) prior to E. coli administration reduces neutrophil infiltration, shortens the inflammatory resolution period, and increases phagocytosis of E. coli by macrophages. When administered at a dose of 100 ng 12h post E. coli infection in a mouse model of peritonitis, MCTR1 reduces the amount of eicosanoids in the exudate.
Maresin conjugates in tissue regeneration 2 (MCTR2) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid in macrophages at the site of inflammation. DHA is oxidized to maresin 1 , which is converted to MCTR1 by glutathione S-transferase Mu 4 or leukotriene C4 synthase then to MCTR2 by γ-glutamyl transferase. MCTR2 accelerates tissue regeneration in planaria (1 and 100 nM). Pretreatment with MCTR2 prior to E. coli administration reduces neutrophil infiltration, shortens the inflammatory resolution period, and increases phagocytosis of E. coli by macrophages. When administered at a dose of 100 ng 12h post E. coli infection in a mouse model of peritonitis, MCTR2 selectively reduced the amount of the eicosanoids PGD2 and PGF2α in the exudate.
Maresin conjugates in tissue regeneration 3 (MCTR3) is a specialized pro-resolving mediator (SPM) synthesized from docosahexaenoic acid in macrophages. DHA is oxidized to maresin 1 , which is converted to MCTR1 by glutathione S-transferase Mu 4 or leukotriene C4 synthase, then to MCTR2 by γ-glutamyl transferase, and to MCTR3 by dipeptidase. MCTR3 accelerates tissue regeneration in planaria (1 and 100 nM) approximately as potently as MCTR2 and more potently than MCTR1. Pretreatment with MCTR3 prior to E. coli administration in mice reduces neutrophil infiltration, shortens the inflammatory resolution period, and increases phagocytosis of E. coli by macrophages. When administered at a dose of 100 ng 12h post E. coli infection in a mouse model of peritonitis, MCTR3 selectively reduces the amount of the eicosanoids PGD2 , PGE2 , PGF2α , and TXB2 in the exudate.