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51.
Jin Zhang Dou Yin Fang Wu Gongliang Zhang Chuanwei Jiang Zhen Li Liecheng Wang Kai Wang 《Neurochemical research》2013,38(8):1616-1623
Adenosine (AD) is a nucleic acid component that is critical for energy metabolism in the body. AD modulates numerous neural functions in the central nervous system, including the sleep-wake cycle. Previous studies have indicated that the A1 receptor (A1R) or A2A receptor (A2AR) may mediate the effects of AD on the sleep-wake cycle. The hypothalamic ventrolateral preoptic area (VLPO) initiates and maintains normal sleep. Histological studies have shown A1R are widely expressed in brain tissue, whereas A2AR expression is limited in the brain and undetectable in the VLPO. We hypothesize therefore, that AD modulates the sleep-wake cycle through A1R in the VLPO. In the present study, bilateral microinjection of AD or an AD transporter inhibitor (s-(4-nitrobenzyl)-6-thioinosine) into the VLPO of rats decreased non-rapid eye movement (NREM) and rapid eye movement (REM) sleep. An A1R agonist (N6-cyclohexyladenosine) produced similar effects in the VLPO. Microinjection of an A1R antagonist (8-cyclopentyl-1,3-dimethylxanthine) into the VLPO enhanced NREM sleep and diminished AD-induced wakefulness. These data indicate that AD enhances wakefulness in the VLPO via A1R in rats. 相似文献
52.
Paul M. Graham Jason Z. Li Xueging Dou Hong Zhu Hara P. Misra Zhenquan Jia Yunbo Li 《Molecular and cellular biochemistry》2013,378(1-2):291-298
Mesalamine (5-aminosalicylic acid, 5-ASA) is known to be the first-line medication for treatment of patients with ulcerative colitis. Studies have demonstrated that ulcerative colitis patients treated with 5-ASA have an overall decrease in the risk of developing colorectal carcinoma. However, the mechanisms underlying 5-ASA-mediated anti-inflammatory and anti-cancer effects are yet to be elucidated. Because peroxynitrite has been critically involved in inflammatory stress and carcinogenesis, this study was undertaken to investigate the effects of 5-ASA in peroxynitrite-induced DNA strand breaks, an important event leading to peroxynitrite-elicited cytotoxicity. Incubation of φX-174 plasmid DNA with the peroxynitrite generator 3-morpholinosydnonimine (SIN-1) led to the formation of both single- and double-stranded DNA breaks in a concentration-dependent manner. The presence of 5-ASA at 0.1 and 1.0 mM was found to significantly inhibit SIN-1-induced DNA strand breaks in a concentration-dependent manner. The consumption of oxygen induced by SIN-1 was found to not be affected by 5-ASA at 0.1–50 mM, indicating that 5-ASA at these concentrations is not involved in the auto-oxidation of SIN-1 to form peroxynitrite. It is observed that 5-ASA at 0.1–1 mM showed considerable inhibition of peroxynitrite-mediated luminol chemiluminescence in a dose-dependent fashion, suggesting that 5-ASA is able to directly scavenge the peroxynitrite. Electron paramagnetic resonance (EPR) spectroscopy in combination with spin-trapping experiments, using 5,5-dimethylpyrroline-N-oxide (DMPO) as spin trap resulting in the formation of DMPO-hydroxyl radical adduct from peroxynitrite, and 5-ASA only at higher concentration (1 mM) inhibited the hydroxyl radical adduct while shifting EPR spectra, indicating that 5-ASA at higher concentrations may generate a more stable free radical species rather than acting purely as a hydroxyl radical scavenger. Taken together, these studies demonstrate for the first time that 5-ASA can potently inhibit peroxynitrite-mediated DNA strand breakage, scavenge peroxynitrite, and affect peroxynitrite-mediated radical formation, which may be responsible, at least partially, for its anti-inflammatory and anti-cancer effects. 相似文献
53.
Zhuren Wang Ying Dou Samuel J. Goodchild Zeineb Es-Salah-Lamoureux David Fedida 《The Journal of general physiology》2013,141(4):431-443
The human ether-á-go-go–related gene (hERG) K+ channel encodes the pore-forming α subunit of the rapid delayed rectifier current, IKr, and has unique activation gating kinetics, in that the α subunit of the channel activates and deactivates very slowly, which focuses the role of IKr current to a critical period during action potential repolarization in the heart. Despite its physiological importance, fundamental mechanistic properties of hERG channel activation gating remain unclear, including how voltage-sensor movement rate limits pore opening. Here, we study this directly by recording voltage-sensor domain currents in mammalian cells for the first time and measuring the rates of voltage-sensor modification by [2-(trimethylammonium)ethyl] methanethiosulfonate chloride (MTSET). Gating currents recorded from hERG channels expressed in mammalian tsA201 cells using low resistance pipettes show two charge systems, defined as Q1 and Q2, with V1/2’s of −55.7 (equivalent charge, z = 1.60) and −54.2 mV (z = 1.30), respectively, with the Q2 charge system carrying approximately two thirds of the overall gating charge. The time constants for charge movement at 0 mV were 2.5 and 36.2 ms for Q1 and Q2, decreasing to 4.3 ms for Q2 at +60 mV, an order of magnitude faster than the time constants of ionic current appearance at these potentials. The voltage and time dependence of Q2 movement closely correlated with the rate of MTSET modification of I521C in the outermost region of the S4 segment, which had a V1/2 of −64 mV and time constants of 36 ± 8.5 ms and 11.6 ± 6.3 ms at 0 and +60 mV, respectively. Modeling of Q1 and Q2 charge systems showed that a minimal scheme of three transitions is sufficient to account for the experimental findings. These data point to activation steps further downstream of voltage-sensor movement that provide the major delays to pore opening in hERG channels. 相似文献
54.
Huiguo Lai Dengfeng Dou Sridhar Aravapalli Tadahisa Teramoto Gerald H. Lushington Tom M. Mwania Kevin R. Alliston David M. Eichhorn Radhakrishnan Padmanabhan William C. Groutas 《Bioorganic & medicinal chemistry》2013,21(1):102-113
1,2-Benzisothiazol-3(2H)-ones and 1,3,4-oxadiazoles individually have recently attracted considerable interest in drug discovery, including as antibacterial and antifungal agents. In this study, a series of functionalized 1,2-benzisothiazol-3(2H)-one—1,3,4-oxadiazole hybrid derivatives were synthesized and subsequently screened against Dengue and West Nile virus proteases. Ten out of twenty-four compounds showed greater than 50% inhibition against DENV2 and WNV proteases ([I] = 10 μM). The IC50 values of compound 7n against DENV2 and WNV NS2B/NS3 were found to be 3.75 ± 0.06 and 4.22 ± 0.07 μM, respectively. The kinetics data support a competitive mode of inhibition by compound 7n. Molecular modeling studies were performed to delineate the putative binding mode of this series of compounds. This study reveals that the hybrid series arising from the linking of the two scaffolds provides a suitable platform for conducting a hit-to-lead optimization campaign via iterative structure–activity relationship studies, in vitro screening and X-ray crystallography. 相似文献
55.
Guo Fu Chen Yang Liu Chun Yun Zhang Chao Shuai Ma Bao Yu Zhang Guang Ce Wang Zhong Xu Dou Ding Lu 《Journal of applied phycology》2013,25(4):1077-1089
Prorocentrum is a common dinoflagellate genus along the Chinese seacoast, which frequently causes harmful algal blooms. Efforts to understand and prevent blooms caused by these harmful species require the development of methods for rapid and precise identification and quantification so that an adequate early warning of harmful algal blooms may be given. Here, we report the development and application of rRNA-targeted oligonucleotide probes for fluorescence in situ hybridization (FISH) to aid in the detection of Prorocentrum micans. The hypervariable D1–D2 regions of a large subunit rDNA of a strain isolated from East China Sea identified as P. micans were first sequenced to design species-specific probes. Analysis of sequences identified as P. micans and deposited in GenBank revealed significant base differences among them and phylogenetic analyses revealed multiple clades within the taxon P. micans. Thus, it is likely that more than one taxonomic and genetically distinct entity has been identified as P. micans, if not misidentified. A series of probes were identified to one of these clades and tested for their specificity. Second, whole cell in situ hybridization procedures were established and the optimal probes were screened among the candidate probes. Next, cross-reactivity was performed to test the specificity of the probes and the detection reliability under various culture conditions, including different nutrient levels, temperatures, and light intensities. Finally, an improved protocol for natural samples was applied to the field material. The designed rRNA-targeted probe was specific, showing no cross-reactivity with other microalgae. The optimized detection protocol could be completed within 1.5 h. All target cells were speculated to be identified during all stages of their whole growth cycle under different culture conditions because the difference in fluorescence intensities throughout the experiment was not significant (p?>?0.05). The cell densities determined by FISH and light microscopy (LM) were comparable, without any significant difference (p?>?0.05) between them. In general, the established FISH probe was promising for specific, rapid, precise detection of a selected set of P. micans in natural samples and served as a good detection model for other Prorocentrum in the future. 相似文献
56.
Y-H Fan J Cheng S A Vasudevan J Dou H Zhang R H Patel I T Ma Y Rojas Y Zhao Y Yu H Zhang J M Shohet J G Nuchtern E S Kim J Yang 《Cell death & disease》2013,4(10):e867
Neuroblastoma (NB) is a common pediatric cancer and contributes to more than 15% of all pediatric cancer-related deaths. Unlike adult tumors, recurrent somatic mutations in NB, such as tumor protein 53 (p53) mutations, occur with relative paucity. In addition, p53 downstream function is intact in NB cells with wild-type p53, suggesting that reactivation of p53 may be a viable therapeutic strategy for NB treatment. Herein, we report that the ubiquitin-specific protease 7 (USP7) inhibitor, , potently induces apoptosis in NB cells with an intact USP7-HDM2-p53 axis but not in NB cells with mutant p53 or without human homolog of MDM2 (HDM2) expression. In this study, we found that P22077 stabilized p53 by inducing HDM2 protein degradation in NB cells. P22077 also significantly augmented the cytotoxic effects of doxorubicin (Dox) and etoposide (VP-16) in NB cells with an intact USP7-HDM2-p53 axis. Moreover, P22077 was found to be able to sensitize chemoresistant LA-N-6 NB cells to chemotherapy. In an in vivo orthotopic NB mouse model, P22077 significantly inhibited the xenograft growth of three NB cell lines. Database analysis of NB patients shows that high expression of USP7 significantly predicts poor outcomes. Together, our data strongly suggest that targeting USP7 is a novel concept in the treatment of NB. USP7-specific inhibitors like P22077 may serve not only as a stand-alone therapy but also as an effective adjunct to current chemotherapeutic regimens for treating NB with an intact USP7-HDM2-p53 axis. P22077相似文献
57.
Liang Zhou Ning Zhang Wenjie Song Nan You Qingjun Li Wei Sun Yong Zhang Desheng Wang Kefeng Dou 《PloS one》2013,8(2)
Background
The prognosis for patients with hepatocellular carcinoma (HCC) is poor, and the mechanisms underlying the development of HCC remain unclear. Notch1 and Notch3 may be involved in malignant transformation, although their roles remain unknown.Materials and Methods
HCC tissues were stained with anti-Notch1 or -Notch3 antibody. The migration and invasion capacities of the cells were measured with transwell cell culture chambers. RT-PCR was used to measure the expression of Notch1 and Notch3 mRNA. Additionally, western blot analysis was used to assess the protein expression of Notch1, Notch3, CD44v6, E-cadherin, matrix metalloproteinase-2 (MMP-2), MMP-9, and urokinase-type plasminogen activator (uPA). RNA interference was used to down-regulate the expression of Notch1 and Notch3. Cell viability was assessed using MTT.Results
Based on immunohistochemistry, high Notch1 expression was correlated with tumor size, tumor grade, metastasis, venous invasion and AJCC TNM stage. High Notch3 expression was only strongly correlated with metastasis, venous invasion and satellite lesions. Kaplan-Meier curves demonstrated that patients with high Notch1 or Notch3 expression were at a significantly increased risk for shortened survival time. In vitro, the down-regulation of Notch1 decreased the migration and invasion capacities of HCC cells by regulating CD44v6, E-cadherin, MMP-2, MMP-9, and uPA via the COX-2 and ERK1/2 pathways. Down-regulation of Notch3 only decreased the invasion capacity of HCC cells by regulating MMP-2 and MMP-9 via the ERK1/2 pathway.Conclusions
Based on the migration and invasion of HCC, we hypothesize that targeting Notch1 may be more useful than Notch3 for designing novel preventive and therapeutic strategies for HCC in the near future. 相似文献58.
C Dou N Ding J Xing C Zhao F Kang T Hou H Quan Y Chen Q Dai F Luo J Xu S Dong 《Cell death & disease》2016,7(3):e2162
Dihydroartemisinin (DHA) is a widely used antimalarial drug isolated from the plant Artemisia annua. Recent studies suggested that DHA has antitumor effects utilizing its reactive oxygen species (ROS) yielding mechanism. Here, we reported that DHA is inhibitory on lipopolysaccharide (LPS)-induced osteoclast (OC) differentiation, fusion and bone-resorption activity in vitro. Intracellular ROS detection revealed that DHA could remarkably increase ROS accumulation during LPS-induced osteoclastogenesis. Moreover, cell apoptosis was also increased by DHA treatment. We found that DHA-activated caspase-3 increased Bax/Bcl-2 ratio during LPS-induced osteoclastogenesis. Meanwhile, the translocation of apoptotic inducing factor (AIF) and the release of cytochrome c from the mitochondria into the cytosol were observed, indicating that ROS-mediated mitochondrial dysfunction is crucial in DHA-induced apoptosis during LPS-induced osteoclastogenesis. In vivo study showed that DHA treatment decreased OC number, prevents bone loss, rescues bone microarchitecture and restores bone strength in LPS-induced bone-loss mouse model. Together, our findings indicate that DHA is protective against LPS-induced bone loss through apoptosis induction of osteoclasts via ROS accumulation and the mitochondria-dependent apoptosis pathway. Therefore, DHA may be considered as a new therapeutic candidate for treating inflammatory bone loss.Bone is a dynamic organ that undergoes continuous remodeling throughout life. Bone homeostasis is maintained by a balanced bone-resorbing and bone-forming process. In this process, hematopoietic stem cells or monocytes/macrophage progenitor cell-derived osteoclasts (OCs) are mainly responsible for bone resorption.1 Abnormal OC function is associated with numerous diseases, and most of them are due to excessive osteoclastic activity. These diseases include osteoporosis, rheumatoid arthritis and periodontitis.2, 3 Two of the most important regulating factors during OC differentiation are receptor activator of nuclear factor κB ligand (RANKL) and macrophage-colony-stimulating factor (M-CSF).4, 5 Binding of RANKL to RANK results in the initiation of the TNF receptor-associated factor 6 signaling, which activates nuclear factor-κB, Akt and MAP kinase (ERk, JNK and p-38), and eventually leads to the proliferation, differentiation and maturation of OCs.6, 7Lipopolysaccharide (LPS) is an important component of the outer membrane of Gram-negative bacteria. In LPS-induced bone loss, many factors are involved including local host response, prostanoids and cytokine production, inflammatory cell recruitment and OC activation.8, 9, 10 Experimental evidence have shown that LPS-mediated inflammation is highly dependent on reactive oxygen species (ROS) and the associated downstream MAPK signaling pathways including ERK, JNK and p-38.11, 12 ROS has been shown having an important role in the process of OC differentiation, survival, activation and bone resorption.13, 14, 15, 16 It has also been proved that ROS production in OC and intracellular hydrogen peroxide accumulation is critical for osteoclastogenesis and skeletal homeostasis.17 Recently, a study reported that LPS induces OC formation via the ROS-mediated JNK and STAT3 pathway, which could be blocked by peroxiredoxin II.18Dihydroartemisinin (DHA) is the main active metabolite isolated from the plant Artemisia annua. DHA has been widely used as first-line therapeutics against falciparum malaria.19 Recent evidence suggested that DHA has antitumor effects because of its unique cytotoxicity mechanism.20 In particular, studies reported that DHA is pro-apoptotic in tumor cell lines regarding breast and prostate cancer.21, 22 Although the detailed mechanism of DHA cytotoxicity and pro-apoptotic effects is not fully understood, DHA-mediated ROS production has a central role.23, 24 However, the effect of DHA on bone health has not been studied.In the present study, we reported that DHA could attenuate LPS-induced OC differentiation, fusion and bone-resorption activity in vitro. Our data showed that DHA-induced cell apoptosis during LPS-induced osteoclastogenesis via intracellular ROS generation and mitochondria-mediated pathways. DHA administration in LPS-induced mouse models decreased OC number and reversed bone loss in vivo. 相似文献
59.
The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar (‘Cocodrie’ and ‘Rondo’), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice. 相似文献
60.
Interest in developing a sustainable technology for fuels and chemicals has unleashed tremendous creativity in metabolic engineering for strain development over the last few years. This is driven by the exceptionally recalcitrant substrate, lignocellulose, and the necessity to keep the costs down for commodity products. Traditional methods of gene expression and evolutionary engineering are more effectively used with the help of synthetic biology and -omics techniques. Compared to the last biomass research peak during the 1980s oil crisis, a more diverse range of microorganisms are being engineered for a greater variety of products, reflecting the broad applicability and effectiveness of today’s gene technology. We review here several prominent and successful metabolic engineering strategies with emphasis on the following four areas: xylose catabolism, inhibitor tolerance, synthetic microbial consortium, and cellulosic oligomer assimilation. 相似文献