Impact of 3-Amino-1,2,4-Triazole (3-AT)-Derived Increase in Hydrogen Peroxide Levels on Inflammation and Metabolism in Human Differentiated Adipocytes

Abstract

Obesity is characterized by an excessive accumulation of fat in adipose tissue, which is associated with oxidative stress and chronic inflammation. Excessive H2O2 levels are degraded by catalase (CAT), the activity of which is decreased in obesity. We investigated the effects of inhibition of catalase activity on metabolism and inflammation by incubating human differentiated adipocytes with 10 mM 3-amino-1,2,4-triazole (3-AT) for 24 h. As expected, the treatment decreased CAT activity and increased intracellular H2O2 levels significantly. Glutathione peroxidase (GPX) activity was also reduced, and the gene expression levels of the antioxidant enzymes GPX4 and peroxiredoxins (1, 3 and 5) were inhibited. Interestingly, this occurred along with lower mRNA levels of the transcription factors nuclear factor (erythroid 2-like 2) and forkhead box O, which are involved in redox homeostasis. However, superoxide dismutase activity and expression were increased. Moreover, 3-AT led to nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activation and increased tumor necrosis alpha and interleukin 6 protein and gene expression levels, while lowering peroxisome proliferator-activated receptor gamma (PPARγ) mRNA and protein levels. These alterations were accompanied by an altered glucose and lipid metabolism. Indeed, adipocytes treated with 3-AT showed reduced basal glucose uptake, reduced glucose transporter type 4 gene and protein expression, reduced lipolysis, reduced AMP-activated protein kinase activation and reduced gene expression of lipases. Our results indicate that increased H2O2 levels caused by 3-AT treatment impair the antioxidant defense system, lower PPARγ expression and initiate inflammation, thus affecting glucose and lipid metabolism in human differentiated adipocytes.

Catalase deletion promotes prediabetic phenotype in mice

“…It alters adipokine signaling pathways, and genes involved in metabolic function, such as transcription factors, inflammation markers, and insulin receptor signaling molecules, and can be toxic to beta cells of the islets of Langerhans [17, 64-67] Beta cells have relatively low levels of antioxidant enzymes [68] and catalase is important for protecting these cells from the toxic effects of ROS [5]. Consistent with such a protective role is the demonstration that acatalasemic mice are more vulnerable to induction of diabetes by alloxan, a treatment that induces ROS formation in beta cells [14].…”

Heme Biosynthetic Pathway is Functionally Linked to Adipogenesis via Mitochondrial Respiratory Activity

“…For the time course experiment, cells were harvested and stored at −80°C for RNA extraction at days 0, 2, 5, 7, 9, 12, and 14. ATZ, a catalase inhibitor that has been demonstrated to attenuate heme biosynthesis , was administered at a concentration of 5 mmol/L on preadipocytes during human adipocyte differentiation and on fully differentiated adipocytes over 48 hours. The concentration of this treatment was based on a previous study .…”

Multitarget Anticancer Agents Based on Histone Deacetylase and Protein Kinase CK2 Inhibitors

“…Specific hydrogen peroxide burst, observed under the action of 7c, may be explained by the presence of a triazole in its structure. The 3-amino-1,2,4-triazole has been shown to be a specific catalase inhibitor and to lead to major increase in cellular H2O2 levels [84]. Altogether, circumvention of cancer drug resistance by DMAT derived hydroxamates is accompanied by oxidative stress in tumor cells due to depolarization of mitochondria.…”

“…2,4,5,6,7-Pentabromo-1-(but-3-yn-1-yl Specific hydrogen peroxide burst, observed under the action of 7c, may be explained by the presence of a triazole in its structure. The 3-amino-1,2,4-triazole has been shown to be a specific catalase inhibitor and to lead to major increase in cellular H 2 O 2 levels [84].…”