Stability evaluation of reference genes for real-time PCR in zebrafish (Danio rerio) exposed to cadmium chloride and subsequently infected by bacteria Aeromonas hydrophila
AQUATIC TOXICOLOGY
Authors: Lang, Xingping; Wang, Lan; Zhang, Zuobing
Abstract
Environmental and occupational cadmium (Cd) toxicity is a global concern, and the model organism zebrafish is an ideal species to investigate Cd toxicity. Among various detecting techniques, quantitative real-time PCR (qPCR) is a sensitive and efficient tool. Stable reference genes are critical for relative qPCR analysis. However, accumulated evidence shows that conventional reference genes can vary significantly under different experimental setups. Here we evaluated the stability of eight candidate reference genes of zebrafish with or without exposure to different concentrations of Cd. The results showed that the best four suitable reference genes in the five selected organs were: (1) spleen: beta-actin> gapdh> ef1 alpha > rpl13 alpha; (2) kidney: rplp2 > rpl7> beta-actin> ef1 alpha; (3) liver: rp17 > rpl13 alpha > beta-actin > ef1 alpha; (4) gills: rplp2> gapdh> rnf7 > ef1 alpha; (5) intestine: ef1 alpha > rnf7> rplp2 > rpl13 alpha. Moreover, we further assessed the expression stability of the four reference genes for Cd immunotoxicology studies in zebrafish. The expression profiles showed that efl alpha in spleen and kidney, rpl13a in liver and rplp2 in intestine were the most suitable reference genes at 12 h and 9 days after the injection with Aeromonas hydrophila following Cd exposure. In gills, the expression of gapdh was more stable than efla after 9 days of bacteria challenge while efla showed a higher stability than gapdh at 12 h after bacteria injection. In conclusion, this study has demonstrated that different tissues of zebrafish have different suitable reference genes after Cd exposure and the subsequently pathogenic insults for qPCR. It emphasized the importance of reference gene evaluation for studies using qPCR, in particular when investigations involve factors not explored previously. (C) 2015 Elsevier B.V. All rights reserved.
Overactivated neddylation pathway in human hepatocellular carcinoma
CANCER MEDICINE
Authors: Yu, Jian; Huang, Wei-long; Xu, Qing-guo; Zhang, Ling; Sun, Shu-han; Zhou, Wei-ping; Yang, Fu
Abstract
Dysregulation of the neddylation pathway is related to various cancers. However, the specific role of the neddylation pathway in human hepatocellular carcinoma (HCC) remains largely unclear. In this study, the neddylation pathway in HCC and adjacent noncancerous liver (ANL) tissues was evaluated by immunohistochemistry (IHC), Western blotting, and qRT-PCR (quantitative real-time polymerase chain reaction). The results showed that the entire neddylation pathway, including NEDD8 (the IHC staining of NEDD8 represents the global-protein neddylation), E1 NEDD8-activating enzymes (NAE1 and UBA3), E2 NEDD8-conjugating enzymes (UBE2F and UBE2M), E3 NEDD8-ligases (MDM2, RBX1 and RNF7), and deneddylation enzymes (COPS5, UCHL1 and USP21), was overactivated in HCC. Furthermore, the upregulation of NEDD8 in HCC was correlated with aggressive characteristics and was an independent risk factor for overall survival (OS) and recurrence-free survival (RFS) in patients with HCC after hepatectomy. The upregulation of NAE1, UBE2M, and UCHL1 in HCC was associated with aggressive characteristics and poor OS and RFS in patients with HCC after hepatectomy. In conclusion, our research reveals that the entire neddylation pathway is overactivated in HCC and associated with clinical characteristics and prognosis of patients with HCC.