Berberine promotes the development of atherosclerosis and foam cell formation by inducing scavenger receptor A expression in macrophage

Berberine is identified to lower the serum cholesterol level in human and hamster through the induction of low density lipoproteins （LDL） receptor in hepatic cells. To evaluate its potential in preventing atherosclerosis, the effect of berberine on atherosclerosis development in apolipoprotcin E-deficient （apoE^-/-） mice was investigated. In apoE^-/- mice, berberine induced in rivo foam cell formation and promoted atheroselerosis development. The foam cell formation induced by berberinc was also observed in mouse RAW264.7 cells, as well as in mouse and human primary macrophages. By inducing scavenger receptor A （SR-A） expression in macrophages, berberine increased the uptake of modified LDL （DiO-Ac-LDL）. Bcrberine-induced SR-A expression was also observed in macrophage foam cells in vivo and in the cells at atherosclerotic lesion. Analysis in RAW264.7 cells indicated that berberine induced SR-A expression by suppressing PTEN expression, which led to sustained Akt activation. Our results suggest that to evaluate the potential of a cholesterol-reducing compound in alleviating atherosclerosis, its effect on the ceils involved in atherosclerosis development, such as macrophages, should also be considered. Promotion of foam cell formation could counter-balance the beneficial effect of lowering serum cholesterol.

MicroRNA sequences modulating inflammation and lipid accumulation in macrophage “foam” cells: Implications for atherosclerosis

Accumulation of macrophage"foam"cells,laden with cholesterol and cholesteryl ester,within the intima of large arteries,is a hallmark of early"fatty streak"lesions which can progress to complex,multicellular atheromatous plaques,involving lipoproteins from the bloodstream and cells of the innate and adaptive immune response.Sterol accumulation triggers induction of genes encoding proteins mediating the atheroprotective cholesterol efflux pathway.Within the arterial intima,however,this mechanism is overwhelmed,leading to distinct changes in macrophage phenotype and inflammatory status.Over the last decade marked gains have been made in understanding of the epigenetic landscape which influence macrophage function,and in particular the importance of small non-coding micro-RNA(miRNA)sequences in this context.This review identifies some of the miRNA sequences which play a key role in regulating"foam"cell formation and atherogenesis,highlighting sequences involved in cholesterol accumulation,those influencing inflammation in sterol-loaded cells,and novel sequences and pathways which may offer new strategies to influence macrophage function within atherosclerotic lesions.

Differential expression of miRNA in THP-1-derived foam cell model induced by drug-containing serum of Yimaijiangzhi decoction

Objective: To investigate the differential expression of miRNA and related biological functions and signaling pathways after the intervention of the THP-1-derived foam cell model with the drug-containing serum of Yimaijiangzhi Decoction. Methods: The experiment was divided into macrophage group, foam cell model group and Yimaijiangzhi drug-containing serum group. THP-1 cells were induced into macrophages by Fopol ester, and induced differentiated macrophages were given ox-LDL to establish foam cell model, and Yimaijiangzhi decoction rat serum was used to intervene the foam cells. Total RNA was extracted from cells in each group for miRNA sequencing, differential expression of miRNA was screened, and relevant target genes were predicted for GO analysis and KEGG analysis, protein interaction network and miRNA-target gene interaction network were established, and RT-qPCR was used to verify the possible signaling pathways for improving atherosclerosis. Result: The difference miRNA between blank group and model group was hsa-miR-302c-3p, hsa-miR-302d-3p, hsa- mir-30d-3p, hsa-mir-3189-3p, hsa-mir-374b-5p, hsa-mir-423-5p, hsa-mir-423-5p, and hsa- mir-4781-3p, hsa-mir-663a;The miRNAs of model group and Yimaijiangzhi drug-containing serum group were hsa-mir-3150a-3p, hsa-mir-7704, hsa-mir-887-3p, hsa-mir-150-5p, hsa- mir-423-5p, hsa-mir-374c-3p, hsa-mir-374c-3p, hsa-mir-374b-5p;The difference of miRNAs prediction target genes between model group and Yimaijiangzhi drug-containing serum group showed that the miRNA prediction target genes were mainly enriched in MAPK signaling pathway, ErbB signaling pathway, Hippo signaling pathway, Wnt signaling pathway and other signaling pathways. SCN1A, PRKACA, MECP2, EIF4E, SRSF1, MBNL1, PRKCA, PPARGC1A may be the potential key targets for the effect of the drug-containing serum of Yimaijiangzhi Decoction on THP-1-derived foam cells. Conclusion: hsa-mir-374c-3p, hsa- mir-423-5p, and hsa-mir-374b-5p are important miRNAs that the drug-containing serum of Yimaijiangzhi Decoction acts on foam cells. The significantly differentially expressed mirnas and significantly enriched related signaling pathways may provide new ideas for the diagnosis and treatment of atherosclerosis.

Thymic Stromal Lmphopoietin Pomotes Macrophage-derived Foam Cell Formation

The effect of thymic stromal lymphopoietin（TSLP） on macrophage-derived foam cell formation and the underlying mechanism were studied. Macrophages isolated from C57BL/6 mice were co-cultured in vitro with different concentrations of TSLP or TSLPR-antibody in the presence of oxidized low density lipoprotein（ox-LDL）. The effects of TSLP on macrophage-derived foam cell formation were observed by using oil red O staining and intracellular lipid determination. The expression levels of foam cell scavenger receptors（CD36 and SRA） as well as ABCA1 and TSLPR were detected by using RT-PCR and Western blotting. As compared with the control group, TSLP treatment significantly promoted lipid accumulation in macrophages, significantly increased protein expression of CD36 and TSLPR in a dose-dependent manner, and significantly reduced the expression of ABCA1 protein in a dose-dependent manner. No significant differences were noted between the TSLPR-antibody group and the control group. TSLP may down-regulate the expression of cholesterol efflux receptor ABCA1 and up-regulate scavenger receptor expression via the TSLPR signaling pathway, thereby promoting macrophage-derived foam cell formation.

Effects of cell wall property on compressive performance of aluminum foams

The effects of cell wall property on the compressive performance of high porosity, closed-cell aluminum foams prepared by gas injection method were investigated. The research was conducted both experimentally and numerically. Foam specimens prepared from conditioned melt were tested under uniaxial compressive loading condition. The cell wall microstructure and fracture were observed through optical microscope（OM） and scanning electron microscope（SEM）, which indicates that the cell wall property is impaired by the defects in cell walls and oxide films on the cell wall surface. Subsequently, finite element（FE） models based on three-dimensional thin shell Kelvin tetrakaidecahedron were developed based on the mechanical properties of the raw material and solid material that are determined by using experimental measurements. The simulation results show that the plateau stress of the nominal stress-strain curve exhibits a linear relationship with the yield strength of the cell wall material. The simulation plateau stress is higher than the experimental data, partly owing to the substitution of solid material for cell wall material in the process of the establishment of FE models.

Cell structure of microcellular combustible object foamed by supercritical carbon dioxide

In order to solve the issue that the combustible objects for cased telescoped ammunition (CTA) didn't burn completely during the combustion process, the microcellular combustible objects were foamed with numerous cells in the micron order to improve the combustion performance by the supercritical carbon dioxide (SCeCO2) foaming technology. As the cell structure determined the combustion properties of microcellular combustible objects, the solubility of SCeCO2 dissolved into the combustible objects was obtained from the gravimetric method, and scanning electron microscope (SEM) was applied to characterize the cell structure under various process conditions of solubility, foaming temperature and foaming time. SEM images indicate that the cell diameter of microcellular combustible objects is in the level of 1 mm and the cell density is about 1011 cell,cm^-3. The microcellular combustible objects fabricated by the SCeCO2 foaming technology are smooth and uniform, and the high specific surface area of cell structure can lead to the significant combustion performance of microcellular combustible object for CTA in the future.

Role of VLDL Receptor in the Process of Foam Cell Formation

The role of very low density lipoprotein receptor (LVLDR) in the process of foam cell formation was investigated. After the primary cultured mouse peritoneal macrophages were incubated with VLDL, β VLDL or low density lipoprotein (LDL), respectively for 24 h and 48 h, foam cells formation was identified by oil red O staining and cellular contents of triglyceride (TG) and total cholesterol (TC) were determined. The mRNA levels of LDLR, LDLR related protein (LRP) and VLDLR were detected by semi quantitative RT PCR. The results demonstrated that VLDL, β VLDL and LDL could increase the contents of TG and TC in macrophages. Cells treated with VLDL or β VLDL showed markedly increased expression of VLDLR and decreased expression of LDLR, whereas LRP was up regulated slightly. For identifying the effect of VLDL receptor on cellular lipid accumulation, ldl A7 VR cells, which expresses VLDLR and trace amount of LRP without functional LDLR, was used to incubate with lipoproteins for further examination. The results elucidated that the uptake of triglyceride rich lipoprotein mediated by VLDLR plays an important role in accumulation of lipid and the formation of foam cells.

Hydrogen peroxide-induced changes in intracellular pH of guard cells precede stomatal closure

Epidermal bioassay demonstrated that benzylamine, a membrane-permeable weak base, can mimick hydrogen peroxide (H2O2) to induce stomatal closure, and butyric acid, a membrane-permeable weak acid, can partly abolish the H2O2-induced stomatal closure. Confocal pH mapping with the probe 5-(and-6)- carboxy seminaphthorhodafluor- 1 - acetoxymethylester (SNARF-1-AM) revealed that H2O2 leads to rapid changes in cytoplasmic and vacuolar pH in guard cells of Viola faba L, i. e. alkalinization of cytoplasmic areas occur red in parallel with a decrease of the vacuolar pH, and that butyric acid pretreatment can abolish alkalinization of cytoplasmic areas and acidification of vacuolar areas of guard cells challenged with H2O2. These results imply that the alkalinization of cytoplasm via efflux of cytosol protons into the vacuole in guard cells challenged with H2O2 is important at an early stage in the signal cascade leading to stomatal closure.

The Effect of Atmospheric Pressure Plasma Corona Discharge on pH, Lipid Content and DNA of Bacterial Cells

Effect of plasma corona discharges on the pH, whole cell lipids and DNA of bacteria is investigated. Results showed an increase in the acidity levels of water due to plasma reactive species which, however, were not responsible for bacterial cell death. No changes in the whole cell lipid contents were observed, while DNA after plasma treatment showed deterioration of the amplified sequences, indicating the possible occurrence of DNA degradation. In conclusion, reactive species produced by plasma discharges affects DNA, possibly contributing to cell death.

The Effect of Neferine on Foam Cell Formation by Anti-low Density Liporotein Oxidation

Oxidatively modified low density lipoprtein (LDL) plays an important role in atheroslerosis (AS) development. To investigate the role of neferine (Nef) in anti-LDL oxidation and foam cell formation, the lipoprotein was derived and subjected to three different treatments: N-LDL (normal LDL), Cu(2+) +LDL and Cu(2+)+Nef+LDL. The LDLs were put at 25℃ for 24 h and the thiobarbituric acid reactive substance (TBARS) values were determined. They were 0. 57 ±0. 02, 6.01±0. 22 and 2. 26±0. 13 nmol/mg protein, respectively. The difference was very significant (P<0.01) for each two groups by t test. Mouse peritoneal macrophage (MΦ) were exposed to 50 μg protein/ml of Cu(2+) + LDL and Cu(2+)+Nef+LDL at 37℃ for 60 h. The tryglyceride (TG) and total cholesterol (TC) content in Mad were assayed. The results showed that Cu(2+) + LDL was more efficient than Cu(2+)+Nef+LDL in stimulating lipid accumulation in MΦ(P <0. 001). The study demonstrated that Nef could inhibit Cu(2+)-mediated LDL oxidation and thereby inhibiting macrophage-derived foam cell formation.

Effects of processing pH stimulation on cooperative bioleaching of chalcopyrite concentrate by free and attached cells

In order to investigate the effects of processing pH stimulation on bioleaching of chalcopyrite by moderate thermophiles,copper leaching rates and the dynamics of microbial community structures of free and attached cells were monitored. The results indicated that when the processing pH values were respectively adjusted to 1.0 and 3.0 on day 14, both free and attached cells experienced an adaptive phase. Meanwhile, the copper leaching rates were 86.9% and 64.0%,respectively, as opposed to a copper leaching rate of 87.5% in the control group without pH stimulation. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis suggested that pH stimulation imposed less impact on the attached organisms than on the free cells, indicating that the attached cells were more resistant to processing pH stimulation than the free cells. Furthermore, adjusting processing pH to 3.0 significantly disrupted both free and attached microbial communities, and the bioleaching system could not recover to the normal status as the control group.

Tensile property of Al-Si closed-cell aluminum foam

Al-Si closed-cell aluminum foams of different densities were prepared by molten body transitional foaming process.The tensile behavior of Al-Si closed-cell aluminum foam was studied and the influence of relative densities on the tensile strength and elastic modulus was also researched.The results show that the fracture surfaces of Al-Si closed-cell aluminum foam display quasi-cleavage fracture consisting of brittle cleavages and ductile dimples.The tensile strength and elastic modulus are strictly affected by the relative density of Al-Si closed-cell aluminum foam.With increasing relative density,the tensile strength increases and the strain at which the peak strength is measured also increases;in addition,the elastic modulus increases with increasing relative density.

Numerical Modeling of the Compression Process of Elastic Open-cell Foams

The random models of open-cell foams that can reflect the actual cell geometrical properties are constructed with the Voronoi technique. The compression process of elastic open-cell foams is simulated with the nonlinear calculation module of finite element analysis program. In order to get the general results applicable to this kind of materials, the dimensionless compressive stress is used and the stress-strain curves of foam models with different geometrical properties are obtained. Then, the influences of open-cell geometrical properties, including the shape of strut cross section, relative density and cell shape irregularity, on the compressive nonlinear mechani- cal performance are analyzed. In addition, the numerical results are compared with the predicted results of cubic staggering model. Nu- merical results indicate that the simulated results reflect the compressive process of foams quite well and the geometrical properties of cell have significant influences on the nonlinear mechanical behavior of foams.

Functional and molecular mechanism of intracellular pH regulation in human inducible pluripotent stem cells

AIM To establish a functional and molecular model of the intracellular pH(pH_i) regulatory mechanism in human induced pluripotent stem cells(hiPSCs).METHODS hiP SCs(HPS0077) were kindly provided by Dr. Dai from the Tri-Service General Hospital(IRB No. B-106-09). Changes in the pH_i were detected either by microspectrofluorimetry or by a multimode reader with a pH-sensitive fluorescent probe, BCECF, and the fluorescent ratio was calibrated by the high K^+/nigericin method. NH_4Cl and Na-acetate prepulse techniques were used to induce rapid intracellular acidosis and alkalization, respectively. The buffering power(β) was calculated from the ΔpH_i induced by perfusing different concentrations of(NH_4)_2SO_4. Western blot techniques and immunocytochemistry staining were used to detect the protein expression of pH_i regulators and pluripotency markers.RESULTS In this study, our results indicated that(1) the steadystate pH_i value was found to be 7.5 ± 0.01(n = 20) and 7.68 ± 0.01(n =20) in HEPES and 5% CO_2/HCO_3^- buffered systems, respectively, which were much greater than that in normal adult cells(7.2);(2) in a CO_2/HCO_3^--buffered system, the values of total intracellular buffering power(β) can be described by the following equation: β_(tot) = 107.79(pH_i)~2-1522.2(pH_i) + 5396.9(correlation coefficient R^2 = 0.85), in the estimated pH_i range of 7.1- 8.0;(3) the Na^+/H^+ exchanger(NHE) and the Na^+/HCO_3^- cotransporter(NBC) were found to be functionally activated for acid extrusion for pHi values less than 7.5 and 7.68, respectively;(4) V-ATPase and some other unknown Na^+-independent acid extruder(s) could only be functionally detected for pHi values less than 7.1;(5) the Cl^-/OH^- exchanger(CHE) and the Cl^- /HCO_3 anion exchanger(AE) were found to be responsible for the weakening of intracellular proton loading;(6) besides the CHE and the AE, a Cl^--independent acid loading mechanism was functionally identified; and(7) in hiPSCs, a strong positive correlation was observed between the loss of pluripotency and the weakening of the intracellular acid extrusion mechanism, which included a decrease in the steady-state pH i value and diminished the functional activity and protein expression of the NHE and the NBC.CONCLUSION For the first time, we established a functional and molecular model of a pHi regulatory mechanism and demonstrated its strong positive correlation with hiPSC pluripotency.

Relationship between Microcellular Foaming Injection Molding Process Parameters and Cell Size

In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed as experimental method, and the Taguchi method is used to analyze significance of effect of process parameters on the cell size. At last the process parameters are focused on melt temperature, injection time, mold temperature and pretidied volume. The significance order from big to small of the effect of each process parameters on cell size is melt temperature, pre-filled volume, injection time, and mold temperature. On the basis of above research, the effect of each process parameter on cell size is further researched. Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively, while the effects of injection time and mold temperature on cell size are less significant.

Carbon Foam Anode Modified by Urea and Its Higher Electrochemical Performance in Marine Benthic Microbial Fuel Cell

Electrode materials have an important effect on the property of microbial fuel cell(MFC). Carbon foam is utilized as an anode and further modified by urea to improve its performance in marine benthic microbial fuel cell(BMFC) with higher voltage and output power. The electrochemical properties of plain carbon foam(PC) and urea-modified carbon foam(UC) are measured respectively. Results show that the UC obtains better wettability after its modification and higher anti-polarization ability than the PC. A novel phenomenon has been found that the electrical potential of the modified UC anode is nearly 100 m V lower than that of the PC, reaching-570 ±10 m V(vs. SCE), and that it also has a much higher electron transfer kinetic activity, reaching 9399.4 m W m-2, which is 566.2-fold higher than that from plain graphite anode(PG). The fuel cell containing the UC anode has the maximum power density(256.0 m W m-2) among the three different BMFCs. Urea would enhance the bacteria biofilm formation with a more diverse microbial community and maintain more electrons, leading to a lower anodic redox potential and higher power output. The paper primarily analyzes why the electrical potential of the modified anode becomes much lower than that of others after urea modification. These results can be utilized to construct a novel BMFC with higher output power and to design the conditioner of voltage booster with a higher conversion ratio. Finally, the carbon foam with a bigger pore size would be a potential anodic material in conventional MFC.

Phase-Field Modeling for the Three-Dimensional Space-Filling Structure of Metal Foam Materials

Phase-field modeling for three-dimensional foam structures is presented. The foam structure, which is generally applicable for porous material design, is geometrically approximated with a space-filling structure, and hence, the analysis of the space-filling structure was performed using the phase field model. An additional term was introduced to the conventional multi-phase field model to satisfy the volume constraint condition. Then, the equations were numerically solved using the finite difference method, and simulations were carried out for several nuclei settings. First, the nuclei were set on complete lattice points for a bcc or fcc arrangement, with a truncated hexagonal structure, which is known as a Kelvin cell, or a rhombic dodecahedron being obtained, respectively. Then, an irregularity was introduced in the initial nuclei arrangement. The results revealed that the truncated hexagonal structure was stable against a slight irregularity, whereas the rhombic polyhedral was destroyed by the instability. Finally, the nuclei were placed randomly, and the relaxation process of a certain cell was traced with the result that every cell leads to a convex polyhedron shape.

Cell-structure and mechanical properties of closed-cell aluminum foam

The density, cell size and structure of closed-cell aluminum foam were measured by optical microscopy and image analysis. The properties and the mechanism of compressive deformation that occur in closed-cell aluminum foam were measured and discussed. The results show that the cell size of foam with density of 0.37 mg/m^3 is distributed in the range of 0.5 4.0 mm. The cell size of foam with density of 0.33 mg/m^3 is distributed in the range of 0.55.0 mm. The cell wall thickness of both types is 0.10.3 mm. The closed-cell aluminum foam almost belongs to isotropic one, with a variation of ±15% in elastic modulus and yield strength in longitudinal and transverse direction. Under compressive loading, foam materials show inhomogeneous macroscopic deformation. The site of the onset of local plastic deformation depends on the cell structure. The shape of cell is more important than size in determining the yielding susceptibility of the cells. At early stage of deformation,the deformation is localized in narrow bands having width of one cells diameter, and outside the bands the cell still remains the original shape. The cells within bands experience large permanent deformation. The band normals are usually within 20° of the loading axis.

Compressive and energy absorption properties of closed-cell magnesium foams

The quasi-static compressive mechanical behavior and deformation mechanism of closed-cell magnesium foams were studied, and the ef- fects of the density of magnesium foams on the compressive and energy absorption properties were also discussed. The results show that the compressive process of closed-cell magnesium foams is characterized by three deformation stages： linear elastic stage, collapsing stage and densification stage. At the linear elastic stage, the peak compressive strength （t70） and Young＇s modulus （E0） increase as the density increases Magnesium foams can absorb energy at the collapsing stage. In a certain strain range, the energy absorption capacity also increases as the density of magnesium foams increases.

Effects of cell size on compressive properties of aluminum foam

The effects of cell size on the quasi-static and dynamic compressive properties of open cell aluminum foams produced by infiltrating process were studied experimentally. The quasi-static and dynamic compressive tests were carried out on MTS 810 system and SHPB(split Hopkinson pressure bar) respectively. It is found that the elastic moduli and compressive strengths of the studied aluminum foam are not only dependent on the relative density but also dependent on the cell size of the foam under both quasi-static loading and dynamic loading. The foams studied show a significant strain rate sensitivity, the flow strength can be improved as much as 112%, and the cell size also has a sound influence on the strain rate sensitivity of the foams. The foams of middle cell size exhibit the highest elastic modulus, the highest flow strength and the most significant strain rate sensitivity.