Multidirectional Changes in Parameters Related to Sulfur Metabolism in Frog Tissues Exposed to Heavy Metal-Related Stress

Abstract

The investigations showed changes of the cystathionine γ-lyase (CTH), 3-mercaptopyruvate sulfurtransferase (MPST) and rhodanese (TST) activity and gene expression in the brain, heart, liver, kidney, skeletal muscles and testes in frogs Pelophylax ridibundus, Xenopus laevis and Xenopus tropicalis in response to Pb 2+ , Hg 2+ and Cd 2+ stress. The results were analyzed jointly with changes in the expression of selected antioxidant enzymes (cytoplasmic and mitochondrial superoxide dismutase, glutathione peroxidase, catalase and thioredoxin reducatase) and with the level of malondialdehyde (a product of lipid peroxidation). The obtained results allowed for confirming the role of sulfurtransferases in the antioxidant protection of tissues exposed to heavy metal ions. Our results revealed different transcriptional responses of the investigated tissues to each of the examined heavy metals. The CTH, MPST and TST genes might be regarded as heavy metal stress-responsive. The CTH gene expression up-regulation was confirmed in the liver (Pb 2+ , Hg 2+ , Cd 2+ ) and skeletal muscle (Hg 2+ ), MPST in the brain (Pb 2+ , Hg 2+ ), kidney (Pb 2+ , Cd 2+ ), skeletal muscle (Pb 2+ , Hg 2+ ,Cd 2+ ) and TST in the brain (Pb 2+ ) and kidney (Pb 2+ , Hg 2+ , Cd 2+ ). Lead, mercury and cadmium toxicity was demonstrated to affect the glutathione (GSH) and cysteine levels, the concentration ratio of reduced to oxidized glutathione ([GSH]/[GSSG]) and the level of sulfane sulfur-containing compounds, which in case of enhanced reactive oxygen species generation can reveal their antioxidative properties. The present report is the first to widely describe the role of the sulfane sulfur/H 2 S generating enzymes and the cysteine/glutathione system in Pb 2+ , Hg 2+ and Cd 2+ stress in various frog tissues, and to explore the mechanisms mediating heavy metal-related stress.

The Expression and Activity of Rhodanese, 3-Mercaptopyruvate Sulfurtransferase, Cystathionine γ-Lyase in the Most Frequently Chosen Cellular Research Models

“…Taking into consideration the level of sulfane sulfur-containing compounds in the tested cell lines ( Table 5 ), we observed that their value was in the range: 41 nmole/mg protein (the SH-SY5Y cells); 190 nmole/mg protein (the MNuMG cells). In cells, sulfane sulfur-containing compounds are produced in the non-oxidative metabolism of cysteine [ 36 , 39 ]. In all the tested lines, the obtained values of the cysteine level were low and equaled on average ca.…”

Heparan Sulfate, Mucopolysaccharidosis IIIB and Sulfur Metabolism Disorders

“…The formation of disulfide protects them against irreversible oxidation, as S-S bonds can be reduced by the thioredoxin/thioredoxin reductase (EC 1.8.1.9) system or the glutathione/glutharedoxin/glutathione reductase (EC 1.8.1.7) systems. Thus, MPST, as well as other two sulfurtransferases-thiosulfate sulfurtransferase (TST, also known as rhodanese, EC 2.8.1.1, Figure 6) and cystathionine γ-lyase (CTH, EC 4.4.1.1, Figure 6), partly contribute to maintaining the redox homeostasis and serves as an antioxidant protein [101,[103][104][105][106]. Their action helps to maintain homeostasis of the sulfane sulfur-containing compounds levels in cells.…”

Heavy Metal Accumulation in the Tissues and Organs of Pelophylax ridibundus (Pallas, 1771) and Pelophylax lessonae (Camerano, 1882) (Amphibia: Ranidae) Living in the Waterbodies of Nizhniy Novgorod

“…Высокие коэффициенты накопления обусловлены, по всей видимости, содержанием в исследованных водных объектах в биодоступной форме цинка, железа, меди (гидрокарбонатные формы, гидроксокомплексы), хрома (хромат анионы), марганца (сернокислые, хлористые и азотнокислые соли). Выявленные межвидовые различия могут быть связаны с особенностями сред обитания близкородственных видов, с присутствием в их рационе пи- Из литературы известно, что, попадая в организм, металлы практически не подвергаются каким-либо существенным превращениям, включаются в биохимический цикл и крайне медленно покидают его (Лобанова, 2008;Моисеенко, 2008;Kaczor-Kami et al, 2020). Находясь в тканях и органах в виде комплекса с белками, аминокислотами и другими биологически активными соединениями, металлы способны вызывать нарушение функций, отравление или гибель организма.…”