H2S is synthesized via CBS/CSE pathway and triggered by cold conditions during Agaricus bisporus storage

BACKGROUND: H2S is proved to be functioning as a signaling molecule in an array of physiological processes in the plant and animal kingdom. However, the H2S synthesis pathway and the responses to cold conditions remain unclear in postharvest mushroom. RESULTS: The biosynthesis of H2S in the Agaricus bisporus mushroom tissues exhibited an increasing tendency during postharvest storage and was significantly triggered by cold treatment. The cystathionine clyase (AbCSE) and cystathionine b-synthase (AbCBS) genes were cloned and proved responsible for H2S biosynthesis. Furthermore, transcriptional and posttranscriptional regulation of AbCSE and AbCBS were crucial for the enzyme activities and subsequent H2S levels. However, the AbMST was not involved in this process. Moreover, the AbCSE and AbCBS genes displayed low identity to the characterized genes, but typical catalytic domains, activity sites, subunit interface sites, and cofactor binding sites were conserved in the respective protein sequences, as revealed by molecular modeling and docking study. The potential transcription factors responsible for the H2S biosynthesis in cold conditions were also provided. CONCLUSIONS: The H2S biosynthetic pathway in postharvest mushroom was unique and distinct to that of other horticultural products.

CBS promoter hypermethylation increases the risk of hypertension and stroke

OBJECTIVES: Cystathionine β-synthase is a major enzyme in the metabolism of plasma homocysteine. Hyperhomocysteinemia is positively associated with hypertension and stroke. The present study was performed to examine the possible effects of Cystathionine β-synthase promoter methylation on the development of hypertension and stroke. METHODS: Using quantitative methylation-specific PCR, we determined the Cystathionine β-synthase methylation levels in 218 healthy individuals and 132 and 243 age- and gender-matched stroke and hypertensive patients, respectively. The relative changes in Cystathionine β-synthase promoter methylation were analyzed using the 2-ΔΔCt method. The percent of the methylated reference of Cystathionine β-synthase was used to represent the Cystathionine β-synthase promoter methylation levels. RESULTS: In this study, the Cystathionine β-synthase promoter methylation levels of hypertensive and stroke participants were both higher than that of the healthy individuals (median percentages of the methylated reference were 50.61%, 38.05% and 30.53%, respectively, all p<0.001). Multivariable analysis showed that Cystathionine β-synthase promoter hypermethylation increased the risk of hypertension [odds ratio, OR (95% confidence interval, CI)=1.035 (1.025-1.045)] and stroke [OR (95% CI)=1.015 (1.003-1.028)]. The area under the curve of Cystathionine β-synthase promoter methylation was 0.844 (95% CI: 0.796-0.892) in male patients with hypertension and 0.722 (95% CI: 0.653-0.799) in male patients with stroke. CONCLUSION: Cystathionine β-synthase promoter hypermethylation increases the risk of hypertension and stroke, especially in male patients.

The Role of CBS in Injury Time Estimation after Brain Contusion / 法医学杂志

OBJECTIVES@#To observe the changes of cystathionine β-synthase （CBS） expression in the cerebral cortex after brain contusion at different times.@*METHODS@#An experimental model of traumatic brain injury （TBI） in mice was established by an improved weight-drop device. Then Western blotting and immunohistochemical examination were used to detect the CBS expression in cerebral cortex around injury at different time points （1 h, 6 h, 12 h, 1 d, 2 d, 3 d, 7 d）.@*RESULTS@#The results of Western blotting revealed that the expression level of CBS was down-regulated and reached its lowest level at the 3rd days after injury, and then restored to normal level after 7 days. The results of immunohistochemistry showed that CBS was present in the normal brain cortex. CBS expression gradually decreased at the 3rd days after injury, and then restored to normal level after 7 days.@*CONCLUSIONS@#CBS has the potential to be a reference index for time estimation after brain contusion in forensic practice.

Immunohistochemccal approach reveals localizatin of cystathionine--lyase and ccystathionine--synthetase in ethanol-induced gastric mucosa damage in mice

Context Hydrogen sulphide (H2S) has been proved to be a neuromodulator and contributes to the maintenance of gastric mucosal integrity in damage caused by anti-inflammatory nonsteroidal drugs. Previously, we demonstrated that H2S synthesis is essential to gastric protection against ethanol. Objective To better understanding the role of H2S and the detailed localization of its production in both normal and injured stomach due to ethanol injection, we studied the expression of cystathionine-γ-lyase (CSE) and cystathionine-β-synthetase (CBS) isoforms in gastric mucosa of mice treated with saline or 50% ethanol. Methods Mice were treated by gavage with saline or 50% ethanol (0.5 mL/25 g). After 1 hour, mice were sacrificed, and gastric tissue was evaluated by histological and immunohistochemical analysis specific for CSE and CBS. Results We have demonstrated a non-specific expression of CBS in the normal gastric mucosa and expression of CSE occurring mainly in the parietal cells of the animals treated with ethanol. Conclusion Thus, we demonstrated that the expression of CBS appears to be constitutive and diffuse across the gastric epithelium, while the expression of CSE appears to be induced in parietal cells by damage agents such as ethanol. .

Contexto O sulfeto de hidrogênio (H2S) tem sido mostrado como um neuromodulador e contribuidor para a manutenção da integridade da mucosa gástrica na lesão causada por drogas antiinflamatórias não esteroidais. Previamente, demonstramos que a síntese de H2S é essencial para a proteção da mucosa gástrica contra a administração de etanol. Objetivo Para compreender o papel do H2S e a localização detalhada de sua produção no estômago normal e após lesão induzida pela administração de etanol, estudou-se a expressão das isoformas cistationina-γ-liase (CSE) e cistationina-β-sintetase (CBS) na mucosa gástrica de camundongos tratados com salina ou etanol 50%. Métodos Os camundongos foram tratados por gavagem com salina ou etanol 50% (0,5 mL/25 g). Após 1 hora, os camundongos foram sacrificados e os tecidos gástricos foram avaliados por análise histológica e imunoistoquímica específica para CBS e CSE. Resultados Foi demonstrado expressão não específica de CBS na mucosa gástrica normal e expressão de CSE ocorrendo principalmente nas células parietais dos animais tratados com etanol. Conclusão Assim, demonstramos que a expressão de CBS parece ser constitutiva e difusa através do epitélio gástrico, enquanto a expressão de CSE parece ser induzida nas células parietais por agentes lesivos como o etanol. .