Wang Y.,Shenyang Pharmaceutical University |
Song Y.-B.,Shenyang Pharmaceutical University |
Yang G.-Z.,General Hospital of Shenyang Military Command |
Cui Y.,Shenyang Pharmaceutical University |
And 5 more authors.
Applied Biochemistry and Biotechnology
In this study, we investigated the functional role of arginines in the C-terminal (65-67) of BmK AGP-SYPU1, an analgesic peptide from the Chinese scorpion Buthus martensii Karsch. Using site-directed mutagenesis, arginines at the C-terminal (65-66) were deleted or added to the C-terminal (67). The genes for three mutants of BmK AGP-SYPU1 were obtained by PCR. An analgesic activity assay was used to evaluate the role of arginine residues in the analgesic activity. The three-dimensional structure of BmK AGP-SYPU1 was established by homology modeling. As a result, we showed that the arginines in the C-terminal are crucial for the analgesic activity and may be located at analgesic functional sites. Our work has implications for further modification of scorpion toxins to obtain new analgesic peptides with enhanced activity. © 2012 Springer Science+Business Media, LLC. Source
Deng L.,Shenyang Pharmaceutical University |
Deng L.,Shenyang University |
Zhang H.-X.,Shenyang Pharmaceutical University |
Wang Y.,463rd Hospital of PLA |
And 7 more authors.
In this study, the role of two conversed tyrosines (Tyr5 and Tyr42) from the scorpion toxin BmK AGP-SYPU1 was investigated with an effective Escherichia coli expression system. Site-directed mutagenesis was used to individually substitute Tyr5 and Tyr42 with hydrophobic or hydrophilic amino acids, and the extent to which these scorpion toxin BmK AGP-SYPU1 tyrosines contribute to analgesic activity was evaluated. The results of the mouse-twisting test showed that Tyr5 and Tyr42 are associated with the analgesic activity of the toxin because the analgesic activities of Y5F and Y42F were significantly increased compared with the rBmK AGP-SYPU1; however, the Y5W had decreased activity. The results of molecular simulation reveal the following: (1) for analgesic activity, the core domain of the scorpion toxin BmK AGP-SYPU1 is key and (2) for pharmacological function, Tyr42 is most likely involved when the core domain conformation is altered. These studies identify a new relationship between the structure and analgesic activity of the scorpion toxin BmK AGP-SYPU1 and are significant for further research and the application of analgesic peptides. © Springer Science+Business Media 2014. Source
Liu X.-W.,General Hospital of Shenyang Military Command |
Zi Y.,463rd Hospital of PLA |
Liu Y.-E.,General Hospital of Shenyang Military Command |
Zhang Y.-B.,General Hospital of Shenyang Military Command |
And 2 more authors.
Melatonin plays a neuroprotective role in different CNS injuries. However, the molecular mechanisms underlying neuroprotection by melatonin are not well understood. Here, we studied the effects of melatonin in hypoxia-induced N2a cells and our results demonstrated that melatonin not only reduced the level of ROS and MDA, induced the increase of SOD, but also increased the cell proliferation and inhibited cell apoptosis in hypoxia-induced N2a cells. Moreover, we identified that melatonin can activate the MAPK/ERK pathway via upregulating the expression of Zip1. Therefore, this study provides a new mechanism of melatonin and need our further study in detail. © 2015. Source
Chen S.,174th Hospital of PLA |
Dong Y.,463rd Hospital of PLA |
Xu C.,174th Hospital of PLA |
Jiang L.,174th Hospital of PLA |
And 4 more authors.
Biochemical and Biophysical Research Communications
The Fas/FasL signaling pathway, controlled by nuclear factor-κB (NFκB) at the transcriptional level, is critical for triggering germ cell apoptosis in response to mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cell (SC) injury, but the exact regulation mechanism remain unknown. Here, we discovered that expression level of Metastasis associated protein 1 (MTA1), a component of the Mi-2/nucleosome remodeling and deacetylase complex, was upregulated in SCs during the early recovery after MEHP exposure. This expression change was in line with the dynamic changes in germ cell apoptosis in response to MEHP treatment. Furthermore, a knockdown of MTA1 by RNAi in SCs was found to impair the MEHP-induced early activation of NFκB pathway and abolish the recruitment of NFκB onto FasL promoter, which consequently diminished the MEHP-triggered FasL induction. Considering that Fas/FasL is a well characterized apoptosis initiating signaling during SCs injury, our results point to a potential "switch on" effect of MTA1, which may govern the activation of NFκB/FasL cascade in MEHP-insulted SCs. Overall, the MTA1/NFκB/FasL circuit may serve as an important defensive/repairing mechanism to help to control the germ cell quality after SCs injury. © 2013 Elsevier Inc. All rights reserved. Source
Qiu J.,Shenyang University |
Li W.,General Hospital of Shenyang Military Command |
Feng S.H.,463rd Hospital of PLA |
Wang M.,463rd Hospital of PLA |
He Z.Y.,Shenyang University
Genetics and Molecular Research
Ginsenoside Rh2 (Rh2) is a ginseng derivative used in Chinese traditional medicine. We investigated whether Rh2 can help prevent Alzheimer's disease symptoms and examined underlying mechanisms. We injected Rh2 into tg2576 Alzheimer's disease model mice and looked for behavioral improvement and senile plaque reduction in brain slices. We measured amyloid precursor protein (APP) metabolism species changes, amyloid beta40 and 42 levels and β, γ secretase activity in primary hippocampal neurons. By living cell staining, we detected surface and endocytosed APP. We also measured cholesterol and lipid rafts in primary neurons. Rh2 treatment significantly improved learning and memory performance at 14 months of age; it also reduced brain senile plaques at this age. Based on in vitro experiments, we found that Rh2 treatment increased soluble APPα (sAPPα) levels, increased CTFα/β ratios, and reduced amyloid beta 40 and 42 concentrations. Surface APP levels dramatically increased. Based on living cell staining, we found that Rh2 inhibited APP endocytosis. Based on lipid removal and reload experiments, we found that Rh2 can modulate APP by reducing cholesterol and lipid raft levels. We concluded that Rh2 improves learning and memory function in Alzheimer's disease model mice, and that this improvement is accomplished by reducing amyloid beta secretion and APP endocytosis, which in turn is achieved by reducing cholesterol and lipid raft concentrations. © FUNPEC-RP. Source