Maoxian Wang

The hydrogen sulfide (H2S)/cystathionine γ‑lyase (CSE) signaling pathway is involved in several inflammatory conditions, where tumor necrosis factor‑α (TNFα) is one of the inflammatory cytokines activated during sepsis. Therefore, the present study investigated the role of the NF‑κB transcription factor binding site in the transcriptional regulation of the CSE gene in 293T cells following treatment with TNFα using luciferase assays, as well as using western blotting and reverse transcription‑quantitative PCR to examine the effect of TNFα on CSE expression in HUVECs. After transfected 293T cells were incubated with various concentrations of TNFα for 1, 3, and 6 h, the wild‑type promoter of the CSE gene increased significantly at 1 h compared to 0 h. By contrast, after the transfected 293T cells were incubated with various concentrations of TNFα for 1 h, the mutant‑type promoter activity of the CSE gene decreased significantly compared to the wild‑type. These results revealed that the DNA sequence GGG​ACA​TTC​C on the CSE gene promoter was directly associated with the transcriptional regulation of the CSE gene in Human cells (293T cells) that's were treated with TNFα. This suggests that TNFα affects CSE gene expression, such that vascular endothelial cells respond to TNFα in the blood by regulating CSE expression. The regulatory mechanisms associated with the effects of TNFα on the transcriptional regulation of the CSE gene in HUVECs and the NF‑κB pathway warrant further investigation.

Cystathionine gamma-lyase (CSE) is one of the essential H2S-producing enzymes, and it regulates diverse functions in connection with cardiovascular function. It is crucial how exogenous H2S regulates CSE expression of the vascular endothelial cell during hypoxia. We examined the transcription and expression of CSE in HUVECs regulated by exogenous H2S with 100 μM during hypoxia by Luciferase assay, Western blotting, and quantitative RT-qPCR. Exogenous H2S influenced on the promoter activity of CSE in HUVECs during hypoxia. The effects of 100 μM H2S on CSE mRNA expression in HUVECs is decreased compared with 0 μM H2S. The consequences of 100 μM H2S on the expression level of CSE protein in HUVECs at two h of hypoxia is reduced compared with 0 μM H2S. These findings suggest that vascular endothelial cells can respond to the signals of hypoxia in the blood, and can respond to changes in H2S concentration in the blood, thus affect the blood vessels themselves.

目 的 鉴定与心血管疾病相关的核因子 κB(NF-κB)调控的基因和小 RNA (microRNA), 探讨疾病发生发展的机制。

We presented a distance-based detection method for visual quantification of mercury ions on a microfluidic paper-based analytical device (μPAD). Dithizone in NaOH solution was used as chromogenic reagent and deposited onto paper channel delimited by hydrophobic wax barrier. Reactions happened between mercury ions and dithizone to form an insoluble colored complex, producing colored precipitate on the paper channel. The length of colored precipitate could be readily measured using the printed ruler along each device. The length of precipitate increase linearly with the mercury concentrations, mercury in sample solution could be quantified by measuring the length of the colored precipitate. Being free of any electronic instruments, this method has the advantages of portability, ease of use, low cost and disposability. This presented method was used to detect mercury ions in a synthetic sample, demonstrating its potential in on-site and real time analysis.

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Hydrogen sulfide (H₂S), an endogenous signaling molecule in mammalian cells, shows a variety of biological effects. Cystathionine γ-lyase (CSE) is a key enzyme in the trans-sulfuration pathway responsible for the production of endogenous H₂S. Whether CSE expression is regulated by hypoxia in mammalian cells remains largely unknown. This study revealed that these regulatory effects changed with time at transcriptional and post-transcriptional levels. Hypoxia regulated CSE expression in mammalian cells in a complex manner; CSE transcription went through a down-regulation and recovery period, while CSE mRNA and protein levels increased during hypoxia. Taken together, the results suggest that CSE can respond to hypoxia through transcriptional and post-transcriptional regulation, and CSE expression can be up-regulated by hypoxia to a certain extent. Therefore, the up-regulation of CSE expression during hypoxia may be useful for increasing the production and concentration of H₂S in mammalian cells and indirectly protecting cells from hypoxia.

Hydrogen sulfide (H₂S), as an endogenous signaling molecule in mammals, shows a variety of biological effects. Cystathionine gamma-lyase (CSE)/H₂S pathway has been implicated in scavenging reactive oxygen species (ROS) in the mammalian cells. Therefore, we first investigated the regulatory effects of exogenously applied hydrogen peroxide (H₂O₂) on CSE expression in the mammalian cells. African green monkey kidney fibroblast-like cells (COS-7 cells) or human embryonic kidney 293 cells (HEK 293 cells) were transfected with CSE promoter-luciferase reporter constructs and treated with H₂O₂ of 1, 5, and 10 μM for 0.5 and 1.5 h at 37°C. The transfected cells were assayed for firefly luciferase activities normalized by Renilla luciferase activity. Human lung adenocarcinoma cells (A549 cells) or human liver cancer cells (SMMC-7721 cells) were treated with H₂O₂ of 1, 5, and 10 μM for 0.5 and 1.5 h at 37°C, and were then harvested and analyzed by Western blotting and quantitative RT-PCR. Our results showed that the treatment of a medium concentration (5 μM) of H₂O₂ at a longer time (1.5 h) upregulated CSE expression in the mammalian cells at the levels of the promoter, message RNA, and protein. Collectively, exogenously applied H₂O₂ can not only markedly affect CSE mRNA and protein expression, but also can affect the CSE promoter activity in the mammalian cells. Our observations indicate that that exogenous H₂O₂ can upregulate the expression of the CSE gene in the mammalian cells, which will provide the possibility of the scavenging effect of the CSE gene indirectly on ROS in the mammalian cells. However, the regulatory mechanism involved in the effects of exogenously applied H₂O₂ on CSE expression in the mammalian cells need be further studied.

Cystathionine γ-lyase (CSE), one of three enzymes in the trans-sulfuration pathway, is responsible for the production of endogenous hydrogen sulfide (H₂S) using l-cysteine or l-homocysteine as a substrate. The regulatory mechanism of CSE by exogenous H₂S remains unknown. The transcription and expression of the CSE gene regulated by exogenous H₂S at approximately physiologic concentrations was investigated using luciferase assay, Western blotting, and quantitative RT-PCR. The results revealed that exogenous H₂S down-regulates the transcription and expression of CSE in mammalian cells at 10–80 μM. Exogenous H₂S at 120 μM increases the transcription and expression of CSE significantly. At a concentration of exogenous H₂S over 160 μM, the transcription and expression of CSE are inhibited completely. These findings suggest that CSE expression has not only a feedback to the enzyme itself at lower concentrations of exogenous H₂S but also can be up-regulated at higher concentrations, and H₂S may become toxic at higher levels.