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Qin F.,University of South China | Zhang Z.,First Hospital of Changsha
Journal of Central South University (Medical Sciences) | Year: 2015

JNK signaling pathway plays an important role in regulation of cell growth, proliferation, differentiation, migration and apoptosis. Studies have shown that JNK signaling pathway is closely related to autophagy, but the underlying mechanisms are not clear. Clarification of the correlation between the JNK signaling pathway and autophagy may provide opportunities for identifying potential molecular targets for the treatment of diseases associated with autophagy.

Yuan L.,Hunan University | Zuo Q.-P.,First Hospital of Changsha
Sensors and Actuators, B: Chemical | Year: 2014

Hydrogen sulfide (H2S) is now recognized as an important biological regulator and plays an important role in a vast number of physiological and pathological processes. However, understanding the important functions of H2S has remained challenging, in part due to the lack of tools for detecting endogenous H2S. Here, compound 2 was synthesized with one step reaction as a novel fluorescent turn-on probe for H2S on the basis of H2S-promoted thiolysis of dinitrophenyl ether. This free probe displayed almost no background signals due to both PET and ICT double signaling quenching mechanism. Thus, this probe shows large fluorescent turn-on and selectivity response to H2S and can be used for the fluorescence detection of both exogenous and endogenous H2S in cells with satisfactory sensitivity. Moreover, it was also applied for direct visualization of H2S in living tissues with two-photon microscopy. In addition to providing a highly sensitive and selective reaction-based fluorescent probe for H2S, the insights into the double signaling quenching mechanism controlling the signal-to-noise ratio of fluorescent turn-on probe may guide the design of fluorescent turn-on probes with better signal-to-noise ratio. © 2014 Elsevier B.V.

Yuan L.,Hunan University | Zuo Q.-P.,First Hospital of Changsha
Chemistry - An Asian Journal | Year: 2014

Hydrogen sulfide (H2S) is connected with various physiological and pathological functions. However, understanding the important functions of H2S remains challenging, in part because of the lack of tools for detecting endogenous H2S. Herein, compounds Ratio-H2S 1/2 are the first FRET-based mitochondrial-targetable dual-excitation ratiometric fluorescent probes for H2S on the basis of H2S-promoted thiolysis of dinitrophenyl ether. With the enhancement of H2S concentration, the excitation peak at λ≈402 nm of the phenolate form of the hydroxycoumarin unit drastically increases, whereas the excitation band centered at λ≈570 nm from rhodamine stays constant and can serve as a reference signal. Thus, the ratios of fluorescence intensities at λ=402 and 570 nm (I402/I570) exhibit a drastic change from 0.048 in the absence of H2S to 0.36 in the presence of 180 μM H 2S; this is a 7.5-fold variation in the excitation ratios. The favorable properties of the probe include the donor and acceptor excitation bands, which exhibit large excitation separations (up to 168 nm separation) and comparable excitation intensities, high sensitivity and selectivity, and function well at physiological pH. In addition, it is demonstrated that the probe can localize in the mitochondria and determine H2S in living cells. It is expected that this strategy will lead to the development of a wide range of mitochondria-targetable dual-excitation ratiometric probes for other analytes with outstanding spectral features, including large separations between the excitation wavelengths and comparable excitation intensities. Don't panic - FRET! The first Förster resonance energy transfer (FRET)-based dual-excitation ratiometric fluorescent probe for monitoring H2S in mitochondrial of living cells is described (see picture). Favorable properties of the probe include large separations of the donor and acceptor excitation bands, comparable excitation intensities, high sensitivity and selectivity, and good function at physiological pH. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Zhang Z.B.,First Hospital of Changsha | Li Z.G.,First Affiliated Hospital of Gannan Medical College
Neurochemical Research | Year: 2012

Cathepsin B, one of major lysosomal cathepsins, and JNK, a downstream component of Rho kinase (ROCK), are two families of proteases, which play an important role in ischemic cell apoptosis. However, the interrelationship between Cathepsin B and JNK in apotosis has not been examined. In the present study, rats were decapitated at 0, 2, 6, 24, 48 h of reperfusion after 2 h of middle cerebral artery occlusion (MCAO); TUNEL-positive cells appeared in the ipsilateral preoptic region during reperfusion after 2-h MCAO, and gradually increased to a peak of 24 h after reperfusion; Phospho-JNK (p-JNK) immunoreactivity, occurring after Cathepsin B expression, was gradually increased and peaked altogether with Cathepsin B at 6-h reperfusion; Fasudil (5 mg/kg, intraperitoneally), an inhibitor of ROCK, decreased the level of p-JNK and apoptotic neurons, and had no effect on cathepsin B; Immunofluorescent double labeling showed that the colocalization of cathepsin B with p-JNK appeared in the preoptic region at 2, 6, 24, 48 h of reperfusion. These findings indicate that a signal transduction pathway by ischemia-reperfusion is most likely to exist: lysosomal cathepsin B-Rho/Rho kinase pathway-JNK signaling pathway-mitochondrial-dependent intrinsic pathway. © Springer Science+Business Media, LLC 2012.

Yu Z.,Central South University | Li W.,Central South University | Li W.,First Hospital of Changsha | Hou D.,Central South University | And 4 more authors.
PLoS ONE | Year: 2015

In recent years, researchers have found that adiponectin (ANP) plays an important role in the pathogenesis of Alzheimer's disease (AD), and low serum concentrations of ANP are associated with AD. Higher plasma ANP level have a protective effect against the development of cognitive decline, suggesting that ANP may affect AD onset. Meanwhile, accumulating evidence supports the crucial role of ANP in the pathogenesis of AD. To study the relationship between ANP gene polymorphisms (rs266729, -11377C>G and rs1501299, G276T) and late-onset AD (LOAD), we carried out a case-control study that included 201 LOAD patients and 257 healthy control subjects. Statistically significant differences were detected in the genotype and allelotype frequency distributions of rs266729 and rs1501299 between the LOAD group and the control group, with a noticeable increase in the G and T allelotype frequency distributions in the LOAD group (P < 0.05). Logistic regression analysis using recessive model and additive model revealed that the rs266729 GG and rs1501299 TT genotypes are associated with a greater risk of LOAD. Haplotype analysis identified four haplotypes: CG, CT, GG, and GT. The frequencies of the CT and GG haplotypes were not significantly different (P > 0.05) between the LOAD group and control group, whereas the CG and GT haplotypes were significantly different (P < 0.05), suggesting a negative correlation between the CG haplotype and LOAD onset (OR = 0.74, 95% CI = 0.57-0.96, P = 0.022), and a positive correlation between the GT haplotype and LOAD onset (OR = 2.29, 95% CI = 1.42-3.68, P = 0.005). Therefore, we speculated that the rs266729 and rs1501299 of ANP gene polymorphisms and the GT and CG haplotypes were associated with LOAD. © 2015 Li et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Wang D.,Central South University | Wang D.,First Hospital of Changsha | Chen J.,First Hospital of Changsha | Chen H.,First Hospital of Changsha | And 5 more authors.
Journal of Biosciences | Year: 2012

Epidemiological studies have indicated that obesity is associated with colorectal cancer. The obesity hormone leptin is considered as a key mediator for cancer development and progression. The present study aims to investigate regulatory effects of leptin on colorectal carcinoma. The expression of leptin and its receptor Ob-R was examined by immunohistochemistry in 108 Chinese patients with colorectal carcinoma. The results showed that leptin/Ob-R expression was significantly associated with T stage, TNM stage, lymph node metastasis, distant metastasis, differentiation and expression of p-mTOR, p-70S6 kinase, and p-Akt. Furthermore, the effects of leptin on proliferation and apoptosis of HCT-116 colon carcinoma cells were determined. The results showed that leptin could stimulate the proliferation and inhibit the apoptosis of HCT-116 colon cells through the PI3K/Akt/mTOR pathway. Ly294002 (a PI3K inhibitor) and rapamycin (an mTOR inhibitor) could prevent the regulatory effects of leptin on the proliferation and apoptosis of HCT-116 cells via abrogating leptin-mediated PI3K/Akt/mTOR pathway. All these results indicated that leptin could regulate proliferation and apoptosis of colorectal carcinoma through the PI3K/Akt/mTOR signalling pathway. © 2011 Indian Academy of Sciences.

Liu F.,Central South University | Liao F.,Central South University | Li W.,First Hospital of Changsha | Han Y.,First Hospital of Shijiazhuang City | Liao D.,Central South University
Molecular Medicine Reports | Year: 2014

Previous studies have demonstrated that progesterone has neuroprotective effects in the central nervous system (CNS) following traumatic brain injury (TBI). Numerous cellular mechanisms have been reported to be important in the neuroprotective effects of progesterone, including the reduction of edema, inflammation and apoptosis, and the inhibition of oxidative stress. However, the effect of progesterone on neuronal protection following TBI remains unclear. The present study aimed to investigate the effects of progesterone on the expression of Nogo-A, an inhibitor of axonal growth, glial fibrillary acidic protein (GFAP), a main component of the glial scar and growth-associated protein-43 (GAP-43), a signaling molecule in neuronal growth in TBI rats. The TBI model was produced by the weight drop method. In total, 75 rats were assigned to three groups: the sham group, TBI group with vehicle treatment and TBI group with progesterone treatment. The protein expression of Nogo-A, GFAP and GAP-43 in the cortex and the hippocampus was examined by immuno-cytochemistry. TBI rats significantly increased the expression of Nogo-A, GFAP, and GAP-43 at 1, 3, 7 and 14 days post-injury. Progesterone significantly decreased the expression of Nogo-A and GFAP, and upregulated the GAP-43 protein. Our findings suggested that progesterone promotes neuroprotection following TBI by inhibiting the expression of Nogo-A and GFAP, and increasing GAP-43 expression.

Huang J.-Q.,First Hospital of Changsha | Yang Y.,First Hospital of Changsha | Yang L.-J.,First Hospital of Changsha
Cancer Research and Clinic | Year: 2013

Gliomas harbor a small population of cells termed glioma stem-like cells (GSC), which have the ability to undergo self-renewal and initiate tumorigenesis. GSCs are resistant to a wide variety of chemotherapeutic agents and possess a remarkable ability to recover from cytotoxic therapy. Furthermore, GSCs play a crucial role in RT failure, as tumors surviving RT are enriched in GSCs. Therefore, an alternative strategy involving selective targeting of this functionally distinct chemo- and radiation resistant small group of GSCs rather than the bulk of the tumor may be more successful in treating this deadly disease. GSC exhibit various alterations to signaling pathway activity, which are associated with self-renewal and neoplastic proliferation. These altered pathways may represent possible targets for GSC.

Li T.,Central South University | Si Z.,Central South University | Hu L.,First Hospital of Changsha | Qi H.,Central South University | Yang M.,Central South University
Sensors and Actuators, B: Chemical | Year: 2012

Ultrasensitive electrochemical immunosensor for the detection of tumor necrosis factor-α (TNF-α) was reported based on Prussian Blue (PB) functionalized ceria nanoparticles (PB-CeO 2) as label. To prepare PB-CeO 2, CeO 2 was first coated with a positively charged chitosan (CS) layer to adsorb negatively charged Fe(CN) 6 3-. Then, with the addition of FeCl 2, PB nanoparticles were synthesized within the CS layer on the CeO 2 surface. The synthesized PB-CeO 2 was found to have high sensitivity toward H 2O 2 detection. Secondary anti-TNF-α antibody (Ab 2) was cross-linked to the PB-CeO 2 through glutaraldehyde to obtain the label (PB-CeO 2-Ab 2). The electrochemical immunosensor for the detection of TNF-α was constructed based on the traditional sandwich structure with the immobilization of primary anti-TNF-α antibody (Ab 1) onto gold nanoparticles (AuNPs) modified carbon nanotube (CNT) surface. With the response of the immunosensor toward 1 mM H 2O 2 as signal, the proposed immunosensor has wide linear range (0.005-5 ng/mL) and low detection limit (2 pg/mL) to TNF-α. The proposed immunosensor preparation strategy successfully demonstrated a simple, sensitive and specific method that can be expanded to the detection of other proteins. © 2012 Elsevier B.V. All rights reserved.

PubMed | First Hospital of Changsha
Type: Journal Article | Journal: Zhonghua xin xue guan bing za zhi | Year: 2015

To explore effects and potential mechanisms of high insulin environment on high density lipoprotein (HDL) generation-related functional protein ABCA1.[(3)H] labeled cholesterol efflux from mature 3T3-L1 adipocytes was detected by liquid scintillation counting. ABCA1 mRNA and protein expression in mature 3T3-L1 adipocytes post stimulation with various concentrations of insulin was detected by real-time fluorescence-based quantitative techniques and Western blot, respectively, in the absence and presence of CHX (cycloheximide, CHX), calpeptin (calpain pathway inhibitor) or MG-132 (proteasome pathway inhibitor).Cholesterol efflux rates were reduced post insulin stimulation in a dose-dependent manner ((7.06 0.27)%, (6.59 0.30)%, (6.34 0.24)%, (5.07 0.40)%, and (4.71 0.40)% at 0, 1, 10, 10, and 10 nmol/L of insulin, P < 0.05). Cholesterol efflux rates decreased in a time-dependent manner post 10 nmol/L insulin stimulation (6.52 0.30)%, (5.59 0.71)%, (5.44 0.37)%, (4.52 0.32)%, and (4.38 0.33)% at 0, 2, 4, 6, 12 h, respectively). ABCA1mRNA levels were not affected by insulin (P > 0.05). ABCA1 protein level was significantly downregulated in 10 nmol/L insulin group compared to 0 nmol/L insulin group (P < 0.01). Compared with the 0 h group, ABCA1 protein level was significantly reduced in 6 h group (P < 0.05) and further reduced in 12 h group (P < 0.01). Both calpeptin and MG-132 could partly reduce insulin-induced degradation of ABCA1. Compared with the negative control group, ABCA1 protein levels were significantly upregulated by cotreatment with calpeptin and MG-132, respectively (both P < 0.01).Our data suggest that high insulin level could promote the ABCA1 protein degradation and reduce cholesterol efflux from mature 3T3-L1 adipocytes through calpain and proteasome pathway, thus, produce a circumference not suitable for nascent HDL formation in 3T3-L1 adipocytes.

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