Hydrogen sulfide (H2S) exerts a host of biological effects ranging from cytotoxicity to cytoprotection. Cytotoxicity of H2S in neurodegenerative diseases may be mediated by N-methyl-D-aspartate receptor (NMDAR) activation. To exploit cytoprotective effects of H2S while minimizing its toxicity, we synthesized a series of H2S-releasing NMDAR antagonists and examined their effects against 1-methyl-4-phenylpyridinium (MPP+)-induced cell death, a cellular model of Parkinson's disease. We observed that cytoprotective effect of H2S-releasing NMDAR antagonists correlated with their ability to increase intracellular sulfane sulfur, but not H2S, levels. These studies suggest that H2S-donor compounds that increase intracellular sulfane sulfur are potentially useful neuroprotective agents against neurodegenerative diseases.
Promoters are DNA regulatory elements located directly upstream or at the 5' end of the transcription initiation site (TSS), which are in charge of gene transcription initiation. With the completion of a large number of microorganism genomics, it is urgent to predict promoters accurately in bacteria by using computational method. In this work, a sequence-based predictor named "iPro70-PseZNC" was designed for identifying sigma70 promoters in prokaryote. In the predictor, the samples of DNA sequences are formulated by a novel pseudo nucleotide composition, called PseZNC, into which the multi-window Z-curve composition and six local DNA structural properties are incorporated. In the 5-fold cross-validation, the area under the curve of receiver operating characteristic of 0.909 was obtained on our benchmark dataset, indicating that the proposed predictor is promising and will provide important guide in this area. Further studies showed that the performance of PseZNC is better than it of multi-window Z-curve composition. For the sake of convenience for researchers, a user-friendly online service was established and can be freely accessible at http://lin.uestc.edu.cn/server/iPro70-PseZNC. The PseZNC approach can be also extended to other DNA-related problems.
Hydrogen sulfide (H2 S) and hydrogen polysulfides (H2 Sn , n>1) are endogenous regulators of many physiological processes. In order to better understand the symbiotic relationship and cellular cross-talk between H2 S and H2 Sn , it is highly desirable to develop single fluorescent probes which enable dual-channel discrimination between H2 S and H2 Sn . Herein, we report the rational design, synthesis, and evaluation of the first dual-detection fluorescent probe DDP-1 that can visualize H2 S and H2 Sn with different fluorescence signals. The probe showed high selectivity and sensitivity to H2 S and H2 Sn in aqueous media and in cells.
Epithelial ovarian cancer (EOC) is the most lethal and aggressive gynecological malignancy, and abnormal cellular metabolism significantly contributes to cancer onset and progression. Here, we report that miR-29b negatively regulates AKT2/AKT3 expression, causing HK2/PKM2 downregulation and leading to a decreased Warburg effect and slowed ovarian cancer progression. Compared to normal ovaries, ovaries with epithelial cancer exhibited lower miR-29b expression at both cellular/histological levels. Glucose consumption and lactate production experiments confirmed miR-29b's regulation of EOC metabolism. A luciferase reporter assay confirmed the direct binding of miR-29b to AKT2/AKT3 3' UTRs. miR-29b silencing correlated with increased expression of AKT2/3, pAKT2/3, HK2, and PKM2. Pyruvic acid and NAD+/NADH levels also changed when miR-29b expression was suppressed; this effect could be blocked by specific AKT inhibitors, suggesting the miR-29b-AKT axis regulates the Warburg effect in ovarian cancer. In xenograft mouse models, miR-29b inhibited tumor formation in vivo. In vivo imaging also demonstrated that miR-29b agomir inhibited the relative uptake of 18F-FDG in the xenograft tumors, suggesting that miR-29b over-expression could negatively modulate tumor glucose metabolism in vivo. Taken together, our study suggests that miR-29b regulates the Warburg effect in EOC via AKT2/AKT3 and may provide novel options for future treatments for EOC.
The effects of a supra-physiological membrane potential shock on the conducting system of the delayed rectifier K(+) channels in the skeletal muscle fibers of frogs were studied. An improved double Vaseline gap voltage clamp technique was used to deliver stimulation pulses and to measure changes in the channel currents. Our results showed that a single 4 ms, -400 mV pulsed shock can cause a reduction in the K(+) channel conductance and a negative-shift of the channel open-threshold. Following the Boltzmann theory of channel voltage-dependence, we analyzed the shock-induced changes in the channel open-probability by employing both two-state and multi-state models. The results indicate a reduction in the number of channel gating particles after the electric shock, which imply possible conformational changes at domains that gate the channels proteins. This study provides further evidence supporting our hypothesis that high intensity electric fields can cause conformational changes in membrane proteins, most likely in the channel gating system. These structural changes in membrane proteins, and therefore their dysfunctions, may be involved in the mechanisms underlying electrical injury.
Panax notoginseng saponin (PNS) is the main active gradient of Chinese traditional medicine Panax notoginseng. Although its prominent therapeutic efficacy has been demonstrated by various researchers, the broader application is restricted by the low bioavailability of PNS. This article aims to discuss PNS's plasma pharmacokinetics after oral administration of bio-adhesive tablet of PNS to beagle dogs and improve its bioavailability in comparison with normal tablet. The bio-adhesive tablet was prepared according to our previous patent, using chitosan as main excipient. A simple and sensitive LC-MS/MS combined with solid-phase extraction (SPE) method for the analysis of PNS in dog's plasma was developed in our previous study, and was validated to apply in the pharmacokinetics study in this work. Three ingredients: Notoginsenoside R1 (R1), Ginsenoside Rg1 (Rg1) and Ginsenoside Rb1 (Rb1) (Figure 1), were chosen as indicators of PNS to analyze it in vivo. Statistically significant increase (P < 0.05) in pharmacokinetic parameters of PNS including AUC and Tmax for R1, Rg1 and Rb1, Cmax for R1 and Rb1, MRT for Rg1 were obtained after oral administration of bio-adhesive tablet of PNS comparing with its normal tablet. The formulation modification of using chitosan to prepare bio-adhesive tablet for oral administration is effective in improving the bioavailability of PNS, thereby enhancing its potential therapeutic effect and broadening its clinical application.
Multidrug resistance (MDR) directly contributes to the clinical failure of chemotherapy in breast cancer (BCA). β-elemene is a natural antitumor drug from plants. We previously confirmed that MDR could be reversed by β-elemene. In this study, we intended to investigate the reversal effect of β-elemene on MDR in human BCA adriacin (Adr) -resistant MCF-7 cells (MCF-7/Adr) and docetaxel (Doc) - resistant MCF-7 cells (MCF-7/Doc) through the gene regulatory network.
MTT-cytotoxic, miRNA microarray, Real-time quantitative PCR, Dual Luciferase Activity Assay, Western blot analysis were performed to investigate the impact of β-elemene on chemo-resistant BCA cell suvival, and its impact on the expression of chemo-resistance specific miRNA and the downstream target genes PTEN and Pgp.
Compared with the miRNAs expression profiles of MCF-7/Adr and MCF-7/Doc cell lines from our previous studies, there were 322 differentially expressed miRNAs in MCF-7/Adr and MCF-7/Doc breast cancer cells with β-elemene intervention (50μM/L) for 30h, and 6 miRNAs were significantly up-regulated and 12 miRNAs were significantly down-regulated in both MCF-7/Adr and MCF-7/Doc. We have testified that 5 miRNA is related to MDR before, in this study, the expression of miR-34a, miR-222, miR-452 and miR-29a can lead to changes of the characteristics of chemo-resistant MCF-7/Adr and MCF-7/Doc. The PTEN expression under intervention of β-elemene was significantly increased and Pgp expression under β-elemene intervention was significantly decreased in both cell lines.
β-elemene could influence MDR related miRNA expression and subsequently regulate the expression of the target genes PTEN and Pgp, which may lead to reduction of the viability of the chemo-resistant breast cancer cells.
Lifestyle factors are well-known important modifiable risk factors for obesity; the association between tobacco smoking and central obesity, however, is largely unknown in the Chinese population. This study examined the relationship between smoking and central obesity in 0.5 million Chinese adults, a population with a low prevalence of general obesity, but a high prevalence of central obesity.
A total of 487,527 adults (200,564 males and 286,963 females), aged 30-79 years, were enrolled in the baseline survey of the China Kadoorie Biobank (CKB) Study conducted during 2004-2008. Waist circumference (WC) and WC/height ratio (WHtR) were used as measures of central obesity.
The prevalence of regular smokers was significantly higher among males (60.6%) than among females (2.2%). The prevalence of central obesity increased with age and BMI levels, with a significant gender difference (females>males). Of note, almost all obese adults (99.4%) were centrally obese regardless of gender. In multivariable regression analyses, adjusting for age, education, physical activity, alcohol use and survey site, regular smoking was inversely associated with BMI in males (standardized regression coefficients, β= -0.093, p<0.001) and females (β= -0.025, p<0.001). Of interest, in the BMI stratification analyses in 18 groups, all βs of regular smoking for WHtR were positive in both genders; the βs showed a significantly greater increasing trend with increasing BMI in males than in females. In the analyses with model adjustment for BMI, the positive associations between regular smoking and WHtR were stronger in males (β= 0.021, p<0.001) than in females (β= 0.008, p<0.001) (p<0.001 for gender difference). WC showed considerably consistent results.
The data indicate that tobacco smoking is an important risk factor for central obesity, but the association is gender-specific and depends on the adjustment for general obesity.
The inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene not only results in tumor initiation, but also mediates tumor metastasis. However, the mechanisms by which VHL inactivation leads to metastasis have not yet been well defined. In this study, the silencing of VHL in 3AO and SKOV3 ovarian cancer cells was found to promote cell motility and to increase the expression of matrix metalloproteinase (MMP)2, MMP9, hypoxia-inducible factor 1-α (HIF-1α) and microRNA (miR)-210. The suppression of HIF-1α with its inhibitor 3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole (YC-1) in VHL-silenced 3AO cells antagonized the pro-migratory activity induced by the VHL deficiency and reversed the upregulation of MMP2, MMP9, HIF-1α and miR-210; however, it had no obvious effect on the VHL protein level. The introduction of miR-210 inhibitor into VHL-silenced 3AO cells resulted in similar changes as those induced by YC-1. Furthermore, vacuole membrane protein 1 (VMP1) was found to be diminished by VHL silencing in a HIF-1α/miR-210-dependent manner. Taken together, our data demonstrate that the loss of VHL stimulates ovarian cancer cell migration by stabilizing HIF-1α, upregulating miR-210 and decreasing VMP1 expression. These results indicate that the aberrant signaling of the VHL/HIF-1α/miR-210/VMP1 pathway may be involved in ovarian cancer aggressiveness.
NADPH oxidase 1 (NOX1) plays a key role in tumorigenesis and metastasis through generating reactive oxygen species (ROS), an important intracellular signaling molecule. However, how it is expressed in gallbladder cancer (GBC) tissue sample and whether it associates with GBC chemoresistance have never been investigated. Our study analyzed the relationship between NOX1 expression and cisplatin-sensitivity both in vivo and in vitro. We found that reduced NOX1 expression promoted cisplatin efficiency in GBC-SD cells, whereas overexpression of which potentially inhibited the sensitivity of cisplatin in SGC-996 cells. Further study into the mechanism we found that increased NOX1 expression elevated intracellular ROS levels, which then activated HIF-1α/MDR1 pathway. These findings established NOX1 a novel accelerant of chemoresistance in GBC, and NOX1-targeted therapeutics might be exploited as a strategy for increasing the efficacy of cisplatin treatment.