SOD1 Is an Integral Yet Insufficient Oxidizer of Hydrogen Sulfide in Trisomy 21 B Lymphocytes and Can Be Augmented by a Pleiotropic Carbon Nanozyme
Down syndrome (DS) is a multisystemic disorder that includes accelerated aging caused by trisomy 21. In particular, overexpression of cystathionine-β-synthase (CBS) is linked to excess intracellular hydrogen sulfide (H<sub>2</sub>S), a mitochondrial toxin at higher concentrations, which...
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Main Authors: | , , , , , , , |
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Format: | Book |
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MDPI AG,
2024-11-01T00:00:00Z.
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Summary: | Down syndrome (DS) is a multisystemic disorder that includes accelerated aging caused by trisomy 21. In particular, overexpression of cystathionine-β-synthase (CBS) is linked to excess intracellular hydrogen sulfide (H<sub>2</sub>S), a mitochondrial toxin at higher concentrations, which impairs cellular viability. Concurrent overexpression of superoxide dismutase 1 (SOD1) may increase oxidative stress by generating excess hydrogen peroxide (H<sub>2</sub>O<sub>2</sub>) while also mitigating the toxic H<sub>2</sub>S burden via a non-canonical sulfide-oxidizing mechanism. We investigated the phenotypic variability in basal H<sub>2</sub>S levels in relation to DS B lymphocyte cell health and SOD1 in H<sub>2</sub>S detoxification. The H<sub>2</sub>S levels were negatively correlated with the DS B lymphocyte growth rates but not with CBS protein. Pharmacological inhibition of SOD1 using LCS-1 significantly increased the H<sub>2</sub>S levels to a greater extent in DS cells while also decreasing the polysulfide products of H<sub>2</sub>S oxidation. However, DS cells exhibited elevated H<sub>2</sub>O<sub>2</sub> and lipid peroxidation, representing potential toxic consequences of SOD1 overexpression. Treatment of DS cells with a pleiotropic carbon nanozyme (pleozymes) decreased the total oxidative stress and reduced the levels of the H<sub>2</sub>S-generating enzymes CBS and 3-mercaptopyruvate sulfurtransferase (MPST). Our results indicate that pleozymes may bridge the protective and deleterious effects of DS SOD1 overexpression on H<sub>2</sub>S metabolism and oxidative stress, respectively, with cytoprotective benefits. |
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Item Description: | 10.3390/antiox13111361 2076-3921 |