Dong-Yang Huang

Shantou University, Swatow, Guangdong, China

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Publications (3)7.34 Total impact

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    ABSTRACT: Cadmium (Cd) and Cd compounds are widely-distributed in the environment and well-known carcinogens. Here, we report that in CdCl2-exposed human bronchial epithelial cells (BEAS-2B), the level of p53 is dramatically decreased in a time- and dose-dependent manner, suggesting that the observed Cd-induced cytotoxicity is not likely due to the pro-apoptotic function of p53. Therefore, this prompted us to further study the responsive pro-apoptotic factors by proteomic approaches. Interestingly, we identified that high levels (20 or 30 μM) of Cd can significantly upregulate the protein levels of eukaryotic translation initiation factor 5A1 (eIF5A1) and redox-sensitive transcription factor NF-κB p65. Moreover, there is an enhanced NF-κB nuclear translocation as well as chromatin-binding in Cd-treated BEAS-2B cells. We also show that small interfering RNA–specific knockdown of eIF5A1 in Cd-exposed cells attenuated the Cd cytotoxicity, indicating the potential role of eIF5A1 in Cd cytotoxicity. As eIF5A1 is reported to be related with cell apoptosis but little is known about its transcriptional control, we hypothesize that NF-κB might likely modulate eIF5A1 gene expression. Notably, by bioinformatic analysis, several potential NF-κB binding sites on the upstream promoter region of eIF5A1 gene can be found. Subsequent chromatin immunoprecipitation assay revealed that indeed there is enhanced NF-κB binding on eIF5A1 promoter region of Cd-treated BEAS-2B cells. Taken together, our findings suggest for the first time a regulatory mechanism for the pro-apoptotic protein eIF5A1 in which its level is possibly modulated by NF-κB in human lung cells.
    Biochemical and Biophysical Research Communications 01/2014; · 2.28 Impact Factor
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    ABSTRACT: Human exposures to cadmium (Cd) compounds are common in the living environment. Cd is toxic, yet, little is known about its effect at the lung cell proteome level. Here, we provide a proteomic analysis of lung epithelial cells (LECs) treated with CdCl2, with the aim of identifying protein response to Cd toxicity. Comparative proteome analysis was conducted to identify global changes in the protein expression profiles of sham-exposed and Cd-treated cells. Proteins were separated by two-dimensional electrophoresis and visualized by silver staining. We reported that while a low level (2 μM) of Cd treatment elicited negligible cytotoxicity and produced no significant proteome changes between the treated group and the control, however, a high level (20 μM) of Cd treatment induced obvious proteome changes and cell death in LECs. Differentially-expressed proteins were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and database searching. The proteins that were significantly up-regulated included heat-shock proteins (HSPs) and antioxidative stress proteins. Pretreatment with the thiol antioxidant glutathione before Cd treatment effectively abrogated the induction of these proteins and prevented cell death. Our results demonstrate that Cd causes oxidative stress-induced cell death, and these differentially-expressed proteins are defense proteins important for fighting against the Cd toxicity, while a low level of Cd may exert a more noticeable effect after long-term exposure, but not after transient exposure.
    Toxicol. Res. 06/2013; 2(4):280-287.
  • Yan-Ming Xu, Dong-Yang Huang, Jen-Fu Chiu, Andy T Y Lau
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    ABSTRACT: Heat shock factors (HSFs) are vital for modulating stress and heat shock-related gene expression in cells. The activity of HSFs is controlled largely by post-translational modifications (PTMs). For example, basal phosphorylation of HSF1 on three serine sites suppresses the heat shock response, and hyperphosphorylation of HSF1 on several other serine and threonine sites by stress-activated kinases results in its activation, while acetylation on K80 inhibits its DNA-binding ability. Sumoylation of HSF2 on K82 regulates its DNA-binding ability, whereas sumoylation of HSF4B on K293 represses its transcriptional activity. With the advancement of proteomic technology, novel PTM sites on various HSFs have been identified with the use of tandem mass spectrometry (MS/MS), but the functions of many of these PTMs are still unclear. Yet, it should be noted that the discovery of these novel PTM sites provided the necessary evidence for the existence of these PTM marks in vivo. Followed by subsequent functional analysis, this would ultimately lead to a better understanding of these PTM marks. MS/MS-based proteomic approach is becoming a gold standard in PTM validation in the field of life science. Here, the recent literature of all known PTMs reported on human HSFs and the resulting functions will be discussed.
    Journal of Proteome Research 04/2012; 11(5):2625-34. · 5.06 Impact Factor