Hydrogen sulfide generation from l-cysteine in the human glioblastoma-astrocytoma U-87 MG and neuroblastoma SHSY5Y cell lines

Hydrogen sulfide (H2S) is endogenously synthesized from l-cysteine in reactions catalyzed by cystathionine beta-synthase (CBS, EC 4.2.1.22) and gamma-cystathionase (CSE, EC 4.4.1.1). The role of 3-mercaptopyruvate sulfurtransferase (MPST, EC 2.8.1.2) in H2S generation is also considered; it could be important for tissues with low CTH activity, e.g. cells of the nervous system. The expression and activity of CBS, CTH, and MPST were detected in the human glioblastoma-astrocytoma (U-87 MG) and neuroblastoma (SHSY5Y) cell lines. In both cell lines, the expression and activity of MPST were the highest among the investigated enzymes, suggesting its possible role in the generation of H2S. The RP-HPLC method was used to determine the concentration of cystathionine and alpha-ketobutyrate, products of the CBS- and CTH-catalyzed reactions. The difference in cystathionine levels between cell homogenates treated with totally CTH-inhibiting concentrations of dl-propargylglycine and without the inhibitor was used to evaluate the activity of CBS. The higher expression and activity of CBS, CTH and MPST in the neuroblastoma cells were associated with more intensive generation of H2S in the presence of 2 mM cysteine. A threefold higher level of sulfane sulfur, a potential source of hydrogen sulfide, was detected in the astrocytoma cells in comparison to the neuroblastoma cells

Effect of S-Allyl -L-Cysteine on MCF-7 cell Line 3-mercaptopyruvate sulfurtransferase/sulfane sulfur system, viability and apoptosis

The S-Allyl-L-cysteine (SAC) component of aged garlic extract (AGE) is proven to have anticancer, antihepatotoxic, neuroprotective and neurotrophic properties. -Cystathionase (CTH), cystathionine -synthase (CBS) and 3-mercaptopyruvate sulfurtransferase (MPST) are involved in H2S/sulfane sulfur endogenous formation from L-cysteine. The aim of the study was to determine the e ect of SAC on MCF-7 cells survival and apoptosis, which is a widely known approach to reduce the number of cancer cells. An additional goal of this paper was to investigate the e ect of SAC on the activity and expression of enzymes involved in H2S production. The experiments were carried out in the human breast adenocarcinoma cell line MCF-7. Changes in the cell viability were determined by MTT assay. Cell survival was determined by flow cytometry (FC). Changes in enzymes expression were analyzed using Western blot. After 24 h and 48 h incubation with 2245 M SAC, induction of late apoptosis was observed. A decrease in cell viability was observed with increasing SAC concentration and incubation time. SAC had no significant cytotoxic e ect on the MCF-7 cells upon all analyzed concentrations. CTH, MPST and CBS expression were confirmed in non-treated MCF-7 cells. Significant decrease in MPST activity at 2245 M SAC after 24 h and 48 h incubation vs. 1000 M SAC was associated with decrease in sulfane sulfur levels. The presented results show promising SAC e ects regarding the deterioration of the MCF-7 cells’ condition in reducing their viability through the downregulation of MPST expression and sulfate sulfur level reduction

Hydrogen sulfide formation in experimental model of acute pancreatitis

Acute pancreatitis (AP) is a disease defined as acute or chronic inflammatory process of the pancreas characterized by premature activation of digestive enzymes within the pancreatic acinar cells and causing pancreatic auto-digestion. In mammalian tissues, H2S is synthesized endogenously from L-cysteine in regulated enzymatic pathways catalyzed by pyridoxal phosphate-dependent enzymes: cystathionine beta-synthase (CBS), gammacystathionase (CTH) and cysteine aminotransferase (CAT) coupled with 3-mercaptopyruvate sulfurtransferase (MPST). In the mitochondria, hydrogen sulfide is oxidized to sulfite, which is then converted to thiosulfate (a sulfane sulfur-containing compound) by thiosulfate sulfurtransferase (rhodanese; TST). Activity and expression of CBS, CTH, MPST, and TST have been determined in vivo in pancreas of the control rats, rats with acute pancreatitis and a sham group. Levels of low-molecular sulfur compounds, such as the reduced and oxidized glutathione, cysteine, cystine and cystathionine, were also determined. This study revealed a significant role of MPST in H2S metabolism in the pancreas. Stress caused by the surgery (sham group) and AP cause a decrease in H2S production associated with a decrease in MPST activity and expression. Markedly higher level of cysteine in the AP pancreas may be caused by a reduced rate of cysteine consumption in a reaction catalyzed by MPST, but it can also be a sign of proteolytic processes occurring in the changed tissu

Hydrogen sulphide production in healthy and ulcerated gastric mucosa of rats

Hydrogen sulphide (H2S) is produced endogenously via two enzymes dependent on pyridoxal phosphate (PLP): cystathionine beta-synthase (CBS, EC 4.2.1.22), cystathionase γ-liase (CTH, EC 4.4.1.1), and a third, 3-mercaptopyruvate sulfurtransferase (MPST, EC 2.8.1.2). H2S strengthens the defence mechanisms of the gastric mucosal barrier, and plays an important role in gastroprotection, including the increased resistance to damage caused by various irritants and non-steroidal anti-inflammatory drugs. The study was conducted to determine the role of H2S in ulcerated gastric mucosa of rats caused by immobilization in cold water (WRS). The activity and expression of γ-cystathionase, cystathionine β-synthase, 3-mercaptopyruvate sulfurtransferase, and rhodanese was compared with healthy mucosa, together with H2S generation, and cysteine, glutathione, and cystathionine levels. The results showed that the defence mechanism against stress is associated with stimulation of the production of H2S in the tissue and confirmed the observed advantageous effect of H2S on healing of gastric ulcers. In case of animals pretreated with exogenous sources of H2S and NaHS, and some changes observed in the ulcerated gastric mucosa tend to return to values found in the healthy tissue, a finding that is in accordance with the previously determined gastroprotective properties of H2S. The results presented in this paper point to the possible role of rhodanese in H2S production in the gastric mucosa of rats, together with the earlier mentioned three enzymes, which are all active in this tissue

Znaczenie diety ketogenicznej w terapii wybranych zaburzeń metabolicznych ― gospodarka węglowodanowa i profil lipidowy

Dieta ketogeniczna (DK) znalazła zastosowanie w leczeniu padaczki u dzieci oraz w terapii niektórych zespołów metabolicznych. Ostatnie doniesienia sugerują również jej wykorzystanie w cukrzycy. Analiza danych literaturowych potwierdziła, że DK może wpływać na podwyższenie stężenia cholesterolu frakcji HDL. Obniżenie glikemii było jedynie efektem krótkoterminowym. Bezpieczeństwo DK u osób z cukrzycą budzi duże wątpliwości, przede wszystkim ze względu na ryzyko hipoglikemii oraz kwasicy ketonowej. Dieta ketogeniczna może doprowadzić do niedoborów żywieniowych, zaburzeń odżywiana oraz efektów ubocznych, takich jak: zaparcia, ból brzucha, nudności, wymioty, ból głowy i osłabienie