DPP-4 inhibition resembles exercise in preventing type 2 diabetes development by inhibiting hepatic protein kinase Cε expression in a mouse model of hyperinsulinemia.

OBJECTIVE: Interventions for hyperinsulinemia (HINS), an early indicator of type 2 diabetes mellitus (T2DM), can significantly reduce the T2DM risk. This study aims to determine how dipeptidyl peptidase-4 (DPP-4) inhibition prevents HINS progression to T2DM through ameliorating hepatic steatosis. METHODS: KKay mice were used as a HINS model and they underwent exercise or received a DPP-4 inhibitor, MK0626. Hepatic steatosis was examined and liver diacylglycerol levels were determined. Human hepatic cells (LO2) were treated with MK0626 or transfected with DPP-4 siRNA. Protein kinase C ε isoform (PKCε) and DPP-4 expression and insulin receptor substrate 1 (IRS-1) phosphorylation were assessed using immunohistochemistry and western blot. RESULTS: KKay mice developed HINS spontaneously at 7 weeks of age. Similar to exercise, MK0626 ameliorated hepatic steatosis and reduced the liver triglyceride and diacylglycerol content. Both exercise and MK0626 suppressed diacylglycerol-induced PKCε expression and restored insulin signaling, which was shown by tyrosine phosphorylation of IRS-1, in the livers of KKay mice. Additionally, silencing DPP-4 or MK0626 treatment decreased PKCε expression in LO2 cells. CONCLUSIONS: Our data demonstrate that DPP-4 inhibition resembles exercise and effectively delays T2DM onset by suppressing hepatic PKCε expression in the HINS mouse model.

Putrescine regulates nitric oxide accumulation in Ganoderma lucidum partly by influencing cellular glutamine levels under heat stress.

When fungi are subjected to abiotic stresses, the polyamines (PAs) level alter significantly. Here, we reveal that the polyamine putrescine (Put) could play an important role in alleviating heat stress(HS)-induced accumulation of nitric oxide (NO). Ornithine decarboxylase (ODC)-silenced mutants that were defective in Put biosynthesis exhibited significantly lower NO levels than the wild type (WT) when subjected to HS. With addition of 5 mM exogenous Put, the ODC-silenced mutant endogenous Put obviously increased under HS. At the same time, the contents of NO in the ODC-silenced mutants recovered to approximately WT levels after the administration of exogenous Put. However, the elevated NO content in the ODC-silenced mutants disappeared when exogenous Put and carboxy-PTIO (PTIO is a specific scavenger of NO) were added. Intriguingly, the content of glutamine (Gln) was significantly increased in the ODC-silenced strains. When exogenous Put was added to the WT, the Gln content was significantly decreased. The appearance of a high level of Gln was accompanied by nitrate reductase (NR) activity reduction. Further studies showed that Put influenced ganoderic acids (GAs) biosynthesis by regulating NO content, possibly through NR, under HS. Our work reported that Put regulates HS-induced NO accumulation by changing the cellular Gln level in filamentous fungi. IMPORTANCE: In our present work, it was HS as an ubiquitous environmental stress that affects the important pharmacological secondary metabolite (GAs) content in G. lucidum. Afterwards, we began to explore the network formed between multiple substances to jointly reduce the massive accumulation of GAs content caused by HS. We firstly focused on Put, a substance that enhances resistance to multiple stresses. Further, we discovered an influence on Put could changing the NO content, which has been shown to decrease the accumulation of GAs via HS. Then, we also found the change of NO content may be due to Put level that would affect intracellular Gln content. It has never been reported. And ultimately, it is Put related network that could reduce HS-inducing secondary metabolite mess in fungi.

N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction coupled with high performance liquid chromatography for the determination of phytohormones in tomatoes.

A N-doped carbon nanotubes-reinforced hollow fiber solid-phase microextraction (N-doped CNTs-HF-SPME) method was developed for determination of two naphthalene-derived phytohormones, 1-naphthalene acetic acid (NAA) and 2-naphthoxyacetic acid (2-NOA), at trace levels in tomatoes. N-doped CNTs were dispersed in ultrapure water with the assistance of surfactant, and then immobilized into the pores of hollow fiber by capillary forces and sonification. The resultant N-doped CNTs-HF was wetted with 1-octanol, subsequently immersed into the tomato samples to extract the target analytes under a magnetic stirring, and then desorbed with methanol by sonication prior to chromatographic analysis. Compared with CNTs, the surface hydrophilicity of N-doped CNTs was improved owing to the doping of nitrogen atoms, and a uniform dispersion was formed, thus greatly simplifying the preparation process and reducing waste of materials. In addition, N-doped CNTs-HF exhibits a more effective extraction performance for NAA and 2-NOA on account of the introduction of Lewis-basic nitrogen. It is worth to mention that owing to the clean-up function of HF, there are not any complicated sample pretreatment procedures prior to the microextraction. To achieve the highest extraction efficiency, important microextraction parameters including the length and the concentration level of N-doped CNTs in surfactant solution, extraction time, desorption conditions such as the type and volume of solvents, pH value, stirring rate and volume of the donor phase were thoroughly investigated and optimized. Under the optimal conditions, the method showed 165- and 123-fold enrichment factors of NAA and 2-NOA, good inter-fiber repeatability and batch-to-batch reproducibility, good linearity with correlation coefficients higher than 0.9990, low limits of detection and quantification (at ng g-1 levels), and satisfactory recoveries in the range of 83.10-108.32% at three spiked levels. The proposed method taking advantages of both excellent adsorption performance of N-doped CNTs and the clean-up function of HF, was a simple, green, efficient and cost-effective enrichment procedure for the determination of trace NAA and 2-NOA in tomatoes.

Wedelolactone Enhances Osteoblastogenesis through ERK- and JNK-mediated BMP2 Expression and Smad/1/5/8 Phosphorylation.

Our previous study showed that wedelolactone, a compound isolated from Ecliptae herba, has the potential to enhance osteoblastogenesis. However, the molecular mechanisms by which wedelolactone promoted osteoblastogenesis from bone marrow mesenchymal stem cells (BMSCs) remain largely unknown. In this study, treatment with wedelolactone (2 µg/mL) for 3, 6, and 9 days resulted in an increase in phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal protein kinase (JNK), and p38. Phosphorylation of mitogen-activated protein kinases (MAPKs), ERK and JNK started to increase on day 3 of treatment, and p38 phosphorylation was increased by day 6 of treatment. Expression of bone morphogenetic protein (BMP2) mRNA and phosphorylation of Smad1/5/8 was enhanced after treatment of cells with wedelolactone for 6 and 9 days. The addition of the JNK inhibitor SP600125, ERK inhibitor PD98059, and p38 inhibitor SB203580 suppressed wedelolactone-induced alkaline-phosphatase activity, bone mineralization, and osteoblastogenesis-related marker genes including Runx2, Bglap, and Sp7. Increased expression of BMP2 mRNA and Smad1/5/8 phosphorylation was blocked by SP600125 and PD98059, but not by SB203580. These results suggested that wedelolactone enhanced osteoblastogenesis through induction of JNK- and ERK-mediated BMP2 expression and Smad1/5/8 phosphorylation.

miR-181a Participates in Contextual Fear Memory Formation Via Activating mTOR Signaling Pathway.

Long-term memory formation has been proven to require gene expression and new protein synthesis. MicroRNAs (miRNAs), as an endogenous small non-coding RNAs, inhibit the expression of their mRNA targets, through which involve in new memory formation. In this study, elevated miR-181a levels were found to be responsible for hippocampal contextual fear memory consolidation. Using a luciferase reporter assay, we indicated that miR-181a targets 2 upstream molecules of mTOR pathway, namely, PRKAA1 and REDD1. Upregulated miR-181a can downregulate the PRKAA1 and REDD1 protein levels and promote mTOR activity to facilitate hippocampal fear memory consolidation. These results indicate that miR-181a is involved in hippocampal contextual fear memory by activating the mTOR signaling pathway. This work provides a novel evidence for the role of miRNAs in memory formation and demonstrates the implication of mTOR signaling pathway in miRNA processing in the adult brain.

Wedelolactone Enhances Osteoblastogenesis but Inhibits Osteoclastogenesis through Sema3A/NRP1/PlexinA1 Pathway.

Bone remodeling balance is maintained by tight coupling of osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Thus, agents with the capacity to regulate osteoblastogenesis and osteoclastogenesis have been investigated for therapy of bone-related diseases such as osteoporosis. In this study, we found that wedelolactone, a compound isolated from Ecliptae herba, and a 9-day incubation fraction of conditioned media obtained from wedelolactone-treated bone marrow mesenchymal stem cell (BMSC) significantly inhibited tartrate-resistant acid phosphatase (TRAP) activity in RANKL-stimulated osteoclastic RAW264.7 cells. Addition of the semaphorin 3A (Sema3A) antibody to the conditioned media partially blocked the medium's inhibitory effects on the RAW264.7 cells. In BMSC, mRNA expression of Sema3A increased in the presence of different wedelolactone concentrations. Blocking Sema3A activity with its antibody reversed wedelolactone-induced alkaline phosphatase activity in BMSC and concurrently enhanced wedelolactone-reduced TRAP activity in osteoclastic RAW264.7 cells. Moreover, in BMSC, wedelolactone enhanced binding of Sema3A with cell-surface receptors, including neuropilin (NRP)1 and plexinA1. Furthermore, nuclear accumulation of ß-catenin, a transcription factor acting downstream of wedelolactone-induced Sema3A signaling, was blocked by the Sema3A antibody. In osteoclastic RAW264.7 cells, conditioned media and wedelolactone promoted the formation of plexin A1-NRP1, but conditioned media also caused the sequestration of the plexin A1-DNAX-activating protein 12 (DAP12) complex and suppressed the phosphorylation of phospholipase C (PLC)γ2. These data suggest that wedelolactone promoted osteoblastogenesis through production of Sema3A, thus inducing the formation of a Sema3A-plexinA1-Nrp1 complex and ß-catenin activation. In osteoclastic RAW264.7 cells, wedelolactone inhibited osteoclastogenesis through sequestration of the plexinA1-DAP12 complex, induced the formation of plexinA1-Nrp1 complex, and suppressed PLCγ2 activation.

[Reduction Effect of Reduced Phosphorus Fertilizer and Combining Organic Fertilizers on Phosphorus Loss of Purple Soil Sloping Field].

In order to better understand the effect of reduced phosphorus fertilizer and combining organic fertilizers on phosphorus loss of purple soil sloping field, three rainfall-runoff events were monitored using field runoff observation method in the purple soil sloping field in 2014. There were six treatments in this research, including optimized fertilization (P), optimized fertilization+pig manure application (MP), optimized fertilization+straw return (SP), optimized fertilization which was reduced by 20%+pig manure application (MDP), optimized fertilization which was reduced by 20%+straw return (SDP), without phosphate (P0). The results indicated that the interflow was the main pathway of runoff for purple soil sloping field. The average contents of total phosphorus (TP) and the phosphorus loss load of overland flow were all much higher than those of the interflow. The overland flow was the main pathway of the phosphorus loss load for purple soil sloping field. Reduced phosphorus fertilizer and combining organic fertilizers had a significant reduction effect on phosphorus loss of purple soil sloping field. Compared with the treatment P, the average content of total phosphorus on SDP was reduced by 57% and that on MDP was reduced by 48% in the storm rainfall. Combining straw was better than pig manure. The average contents of the phosphorus loss load of typical rainfall changed between 0.01 and 0.26 kg·hm-2. In different fertilization treatments, the average contents of the phosphorus loss load followed the order of P > MP > SP > MDP > SDP > P0. Reduced phosphorus fertilizer and combining organic fertilizers had a significant reduction effect on phosphorus loss of overland flow, but increased soil phosphorus leaching for purple soil sloping field.

[Variation Characteristics of Inorganic Phosphorus in Purple Soil Profile Under Different Conservation Tillage Treatments].

In this study the effects of tillage methods (rice-winter paddy field conventional farming, CF; rice-winter paddy field combing ridge with no-tillage, RNT1; rice-wheat or rape combing ridge with no-tillage, RNT2; rice-wheat or rape conventional paddy-upland rotation tillage, CR) on purple soil profile of different forms of inorganic phosphorus distribution characteristics were investigated in a long-term experimental site established in 1990, Chongqing City, China. The results showed that compared to the status before the experiment, the total phosphorus, available phosphorus and various morphologies of inorganic phosphorus all increased to a certain degree in the soils with different long-term tillage treatments,and the contents of different forms of inorganic phosphorus in soil size ranked as RNT2> CF> CR> RNT1. Except that the contents of Fe-P in the lower layer were higher than those in the upper layer, contents of Ca2-P, Ca8-P, Al-P, Ca10-P and O-P in the arable layers were all higher than those in the lower layers. The effects of farming practices on the availability of various phosphorus forms were significant. They were in the order of CR> RNT> CF. Long-term conventional paddy-upland rotation tillage was more advantageous to crops in the absorption of phosphorus. It was shown by relevant analysis that the contribution of various groups of inorganic phosphorus to purple soil was in the order of Ca2-P(0.9369)> Al-P(0.9158)> Ca8-P(0.9012)> Fe-P(0.8287)> Ca10-P(0.8059)> O-P(0.7472).

A cell-based model of bone remodeling for identifying activity of icarrin in the treatment of osteoporosis.

The activity of icarrin (a flavonoid from Herba epimedii) was investigated in the regulation of bone remodeling, a process coupled by osteoblast-mediated bone forming and osteoclast-mediated bone resorption. By directly co-culturing mouse bone marrow stromal cells and mouse preosteoclastic RAW264.7, and transwell co-culturing rat ovarian follicular granulosa cells (FGC), a 30 % increase in alkaline phosphatase (ALP) activity and 25 % increase in estradiol level occurred. Compared with the antiresorptive drug, alendronate, and an anabolic drug, PTH1-34, icarrin possessed all of the positive effects on the co-culture by increasing ALP activity, estradiol production and decreasing tartrate-resistant acid phosphatase activity. A similar action of icarrin occurred on co-culture of mesenchymal stem cells, mouse peripheral blood mononuclear cells, and FGC. Overall, by using a co-cultured cell-based in vitro screening assay, icarrin is suggested as a new class of dual-action therapeutic agent for osteoporosis.

[Different prevalence of impaired glucose tolerance between hyperinsulinemic and normoinsulinemic subjects].

OBJECTIVE: To study the impact of different insulin levels on the conversion from impaired glucose tolerance (IGT) to type 2 diabetes mellitus (T2DM), through analysis of different glycometabolism condition among quinquagenarian population. METHODS: Subjects enrolled were Beijing habitants who received annual physical examination [including oral glucose tolerance test (OGTT)] in the Chinese PLA General Hospital from 2005 - 2007. According to the OGTT results, the subjects were divided into three groups, including normal glucose tolerance-non-hyperinsulinemia group (NGT-NHIns), IGT-hyperinsulinemia group (IGT-HIns) and IGT-non-hyperinsulinemia group (IGT-NHINS). The prognosis between the year 2009 and 2010 of the three groups was observed. Hyperinsulinemia was diagnosed with fasting serum insulin ≥ 15 mU/L and/or 2-hour serum insulin ≥ 80 mU/L after glucose loading. RESULTS: The rate of case number of conversion to T2DM in IGT-NHIns group (42/133) was higher than that in IGT-HIns group (24/154) or NGT-NHIns group (12/126). The HOMA insulin resistance index (HOMA-IR) of individuals with IGT-NHIns was lower than that of IGT-HIns [0.96 (0.40, 3.53) vs 2.04 (0.59, 23.20), P < 0.05], while whole body insulin sensitivity index (WBISI) was higher than that of IGT-HIns [7.48 (3.20, 31.35) vs 3.28 (0.86, 7.67), P < 0.05]. Modified ß-cell function index (MBCI) and insulin secretion index (ISI) in IGT-NHIns was poorer than that of IGT-HIns respectively [2.57 (0.58, 10.98) vs 5.17 (1.04, 65.09); 7.66 (0.99, 28.40) vs 17.56 (4.18, 96.46), all P values < 0.01]. CONCLUSIONS: The risk of IGT-NHIns progressing into T2DM is higher than that of IGT-HIns. For the prevention of T2DM, individuals with IGT-NHIns should be paid more attention than keeping an eye on IGT-HIns patients. Early control of risk factors could protect ß cell function and prevent the progression to T2DM.

[Spatial variability and evaluation of soil heavy metal contamination in the urban-transect of Shanghai].

Soil heavy metal concentrations along the typical urban-transect in Shanghai were analyzed to indicate the effect of urbanization and industrialization on soil environment quality. Spatial variation structure and distribution of 5 heavy metals (Cu, Cr, Mn, Pb and Zn) in the top soil of urban-transect were analyzed. The single pollution index and the composite pollution index were used to evaluate the soil heavy metal pollution. The results showed that the average concentrations of the Cu, Pb, Zn, Cr, Mn were 27.80, 28.86, 99.36, 87.72, 556.97 mg x kg(-1), respectively. Cu, Cr, Mn, Pb and Zn were medium in variability, Mn was distributed lognormally, while Cu, Cr, Pb and Zn were distributed normally. The results of semivariance analysis showed that Mn was fit for the exponential model, Cr, Pb, Cu and Zn were fit for the linear model. The spatial distribution maps of heavy metal content of the topsoil in this city-transect were produced by means of the universal kriging interpolation. Cu was spatially distributed in ribbon, Cr and Mn were distributed in island, while the spatial distribution of Pb and Zn showed the mixed characteristic of ribbon and island. With the result of soil pollution evaluation, it showed that the pollution of Cr, Zn and Pb was relatively severe. Cr, Zn, Pb, Mn and Cu were significantly correlated, and heavy metal co-contamination existed in soil. Difference of soil heavy metals pollution along "Urban-suburban-rural" was obvious, the special variation of heavy metal concentrations in the soil closely related to the degree of industrialization and urbanization of the city.

[Risks of type 2 diabetes mellitus and impaired glucose regulation among elderly patients with essential hypertension: a 10-years cohort study].

OBJECTIVE: To explore the incidence of type 2 diabetes mellitus (T2DM) and impaired glucose regulation (IGR) among elderly patients with and without hypertension during a follow-up period of 10 years. METHODS: The subjects were elderly patients (> 60 years old) undergoing annual health examinations at our hospital. And the previously diagnosed T2DM and IGR patients were excluded. And the incidence and risk factors were analyzed by Kaplan-Meier method and COX's proportional hazard. RESULTS: Among a total of 1136 subjects, 582 were enrolled. They were divided into essential hypertension group (HT, n = 384) and non-essential hypertension group (NHT, n = 198) (including new-onset 67 subjects). During a 10-year follow-up, the incidence of new-onset diabetes was 27.6% in HT group and 18.7% in NHT group (HR = 1.48; 95%CI: (1.07 - 2.04), P < 0.05). And the incidence density of T2DM were 33.8‰ and 20.6‰ respectively in two groups. There was no difference in the prevalence of IGR among HT and NHT groups and no difference was found in the prevalence of T2DM or IGR among new-onset HT and NHT groups. The independent risk factors of T2DM was dyslipidemia (HR = 1.459; 95%CI: 1.027 - 2.072, P < 0.05) and hypertension (HR = 1.516; 95%CI: 1.039 - 2.212, P < 0.05) based upon the COX's proportional hazard analysis. Dyslipidemia (HR = 1.545; 95%CI: 1.087 - 2.195, P < 0.05) and hypertension (HR = 1.524; 95%CI: 1.044 - 2.224, P < 0.05) were also independent risk factors of abnormal glycometabolism (T2DM and IGR). Kaplan-Meier analysis indicated that the accumulative incidence of DM and abnormal glycometabolism was different between the HT and NHT groups. CONCLUSION: The DM risk is 1.516 folds higher in elderly patients with HT than in those without. According to multivariate analysis, hypertension and dyslipidemia are independent risk factors of T2DM and abnormal glycometabolism (T2DM and IGR).

Taxol-induced alteration of intracellular amino-acid profile related to human cervical carcinoma HeLa cell death.

The anti-tumor action of Taxol was investigated in the changes of amino-acids involved in tumor cell survival. By tracing the intracellular amino-acid profiles of HeLa cells treated with non-conditioned and three conditioned media (Taxol, L-alanine, and Taxol + L-alanine), it was observed that an alteration of amino-acid metabolism participates in Taxol-induced death of HeLa cells. The contents of 18 out of 21 detected amino-acids are 5-95% and the ones of lysine and methionine are 158 and 117% of the corresponding contents in the control after treatment with Taxol for 24 h, respectively. Addition of L-alanine inhibited cell apoptosis upon Taxol treatment by partially blocking the increase of lysine and methionine and reversing decrease trend of alanine, glycine, and glutamic acid. These results suggest that interference of amino-acid metabolism might be an important mechanism of Taxol cytotoxicity.

Water and heat transport in hilly red soil of southern China: I. Experiment and analysis.

Studies on coupled transfer of soil moisture and heat have been widely carried out for decades. However, little work has been done on red soils, widespread in southern China. The simultaneous transfer of soil moisture and heat depended on soil physical properties and the climate conditions. Red soil is heavy clay and high content of free iron and aluminum oxide. The climate conditions are characterized by the clear four seasons and the serious seasonal drought. The great air temperature differences annually and diurnally result in significant fluctuation in soil temperature in top layer. The closed and evaporating columns experiments with red soil were conducted to simulate the coupled transfer of soil water and heat under the overlaying and opening fields' conditions, and to analyze the effects of soil temperature gradient on the water transfer and the effects of initial soil water contents on the transfer of soil water and heat. The closed and evaporating columns were designed similarly with about 18 degrees C temperatures differences between the top and bottom boundary, except of the upper end closed or exposed to the air, respectively. Results showed that in the closed column, water moved towards the cold end driven by temperature gradient, while the transported water decreased with the increasing initial soil water content until the initial soil water content reached to field capacity equivalent, when almost no changes for the soil moisture profile. In the evaporating column, the net transport of soil water was simultaneously driven by evaporation and temperature gradients, and the drier soil was more influenced by temperature gradient than by evaporation. In drier soil, it took a longer time for the temperature to reach equilibrium, because of more net amount of transported water.

Water and heat transport in hilly red soil of southern China: II. Modeling and simulation.

Simulation models of heat and water transport have not been rigorously tested for the red soils of southern China. Based on the theory of nonisothermal water-heat coupled transfer, a simulation model, programmed in Visual Basic 6.0, was developed to predict the coupled transfer of water and heat in hilly red soil. A series of soil column experiments for soil water and heat transfer, including soil columns with closed and evaporating top end, were used to test the simulation model. Results showed that in the closed columns, the temporal and spatial distribution of moisture and heat could be very well predicted by the model, while in the evaporating columns, the simulated soil water contents were somewhat different from the observed ones. In the heat flow equation from Taylor and Lary (1964), the effects of soil water evaporation on the heat flow is not involved, which may be the main reason for the differences between simulated and observed results. The predicted temperatures were not in agreement with the observed one with thermal conductivities calculated by de Vries and Wierenga equations, so that it is suggested that K(h), soil heat conductivity, be multiplied by 8.0 for the first 6.5 h and by 1.2 later on. Sensitivity analysis of soil water and heat coefficients showed that the saturated hydraulic conductivity, K(S), and the water diffusivity, D(theta), had great effects on soil water transport; the variation of soil porosity led to the difference of soil thermal properties, and accordingly changed temperature redistribution, which would affect water redistribution.