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.

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.

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.

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.

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.

Ginsenoside metabolite IH 901 reduced foam cell formation in vitro

Objective To explore the roles of IH 901 on the formation of foam cell sourced from rat peritoneal macrophage.Methods The cultured rat peritoneal macrophages were incubated with ox-LDL to get foam cell as model group.Different doses of IH 901 were added into the culture medium(10 μM,25 μM,50 μM).Foam cell was stained by oil red O.The content of total cholesterol and cholesterol ester were examined to show the formation of foam cells.And the concentrations of TNF-α and IL-1 in culture supernatant were detected.The expression of NF-κB,perilipin and CD36 were measured by western blotting.Results Compared with model group,the formation of foam cell was significantly reduced by IH 901 treatment(50 μM,25 μM),while the amount of living cells of 50 μM group was lessened compared with other groups.Compared with model group,the contents of total cholesterol,cholesterol ester and CE/TC ratio were significantly reduced in IH 901 50 μM and 25 μM groups(P<0.05).Meanwhile,there was obvious difference among IH 901 groups.The concentrations of TNF-α and IL-1 in IH 901 high and middle dose groups were reduced remarkable compared with model group.The changes of expression of NF-κB,perilipin and CD36 showed the similar tendency of the results above.There were no noticeable difference between model group and IH 901 low dose group.Conclusions IH 901 could reduce the formation of foam cell sourced from rat peritoneal macrophage dose dependently.The mechanism may depend on the effects of IH 901 reducing the inflammation reaction of macrophage and the expression of perilipin.

Lipid homeostasis and the formation of macrophage-derived foam cells in atherosclerosis

Atherosclerosis is a chronic,inflammatory disorder characterized by the deposition of excess lipids in the arterial intima.The formation of macrophage-derived foam cells in a plaque is a hallmark of the development of atherosclerosis.Lipid homeostasis,especially cho-lesterol homeostasis,plays a crucial role during the formation of foam cells.Recently,lipid droplet-associated proteins,including PAT and CIDE family proteins,have been shown to control the development of athero-sclerosis by regulating the formation,growth,stabiliza-tion and functions of lipid droplets in macrophage-derived foam cells.This review focuses on the potential mechanisms of formation of macrophage-derived foam cells in atherosclerosis with particular emphasis on the role of lipid homeostasis and lipid droplet-associated proteins.Understanding the process of foam cell for-mation will aid in the future discovery of novel thera-peutic interventions for atherosclerosis.

Effects of Andrographolide on the Activation of Mitogen Activated Protein Kinases and Nuclear Factor-κ B in Mouse Peritoneal Macrophage-derived Foam Cells

Objective： To observe the effect of andrographolide on the activation of mitogen-activated protein kinases （MAPKs） and expression of nuclear factor- kB （NF-kB） in macrophage foam cells. Methods： The mouse peritoneal macrophages were cultured in the media in the presence of oxidized low-density lipoprotein （ox-LDL）, ox-LDL＋andrographolide, or neither （control）. The phosphorylation of MAPK molecules （p38MAPK, JNK, ERK1/2） and the expressions of NK- kB p65 were examined by Western blot. Results： As compared with cells in the control group, the expressions of phospho-p38 and NF- kB p65 were increased in the cells cultured with either ox-LDL or ox-LDL＋andrographolide （P〈0.01）, but attenuated significantly in the presence of ox-LDL＋ andrographolide when compared with ox-LDL （P〈0.05）. The phospho-JNK increased in the presence of either ox-LDL or ox-LDL＋andrographolide when compared with control cells （P〈0.01）, but no significant difference existed between ox-LDL and ox-LDL＋andrographolide （P〉0.05）. The expression of phospho-ERK1/2 was increased in the presence of ox-LDL compared with the control cells （P〈0.01）, but no significant differences existed between the cells cultured in the presence of ox-LDL＋andrographolide and the control medium （P〉0.05）. Conclusions： Andrographolide could inhibit the activation of ERK1/2, p38MAPK and NK-kB induced by ox-LDL in macrophage foam cells, which might be one of its mechanisms in preventing atherosclerosis.

Effect of IL-10 on formation of foam cell induced by ox-LDL

Atherosclerosis is a chronic disease that causes various cardiovascular complications.It has been realized that cellular and humoral immunity plays crucial roles in atherogenic lesion formation.In this study the effects of lipopolysaccharide(LPS)and interleukin-10(IL-10)on the formation of foam cells during the early stages of ath-erosclerosis have been investigated.Macrophage was induced by phorbol myristate acetate(PMA)treatment on THP-1 cells.The cells were further stimulated by ox-LDL,ox-LDL plus LPS,ox-LDL plus IL-10 and LPS.By using an oil red O staining technique,the formation of foam cells was evaluated by lipid granules formation in the cells.The ratio of foam cell formation was increased from(9.77±1.70)%to(16.27±2.27)%after 24 h stimulation with ox-LDL,and the increase was observed with incub-ating time.The foam cells were significantly increased in the presence of LPS in a dose-dependent manner.The max-imum increase of about 40%was observed.However,the significant elevation by LPS was abrogated when IL-10 was added.These results indicated that IL-10 can effectively prevent the formation of foam cells induced by ox-LDL with or without LPS.This study demonstrates that ox-LDL can cause foam cell formation from macrophages in vitro.LPS can significantly accelerate this event.IL-10,an anti-inflammatory cytokine,can inhibit the effect of ox-LDL and LPS.These results indicate that inflammatory effects in blood vessels can speed up foam cell formation.The inhibitive effect of IL-10 is an important factor for delaying atherosclerosis processes.

Effect of atorvastatin on uptake of ox-LDL and expression of CD36 antigen during the transformation from U937cell into foam cell

Background The expression degree of CD36 in monocytes-macrophages is one of the important factors affecting lipid accumulation and foam cell transformation. Atorvastatin has anti-atherosclerosis as well as lowering blood lipid. Thus, we investigate the effect of atorvastatin on expression of CD36 and uptake of oxidized low-density lipoprotein（ox-LDL） during the formation of macrophage-derived foam cells human U937 cell line. Methods U937 cells were incubated with ox-LDL 80 mg / L to induce their transformation into foam cells. The medium was pretreated with atorvastatin 10 nmol / L. The contents of total cholesterol（TC） and cholesterol ester（CE） in cells were measured by the enzymatic fluorometric method. CD36 protein and mRNA expression levels were measured by flow cytometry and reverse transcription PCR. Results After incubated with ox-LDL, the contents of TC and CE in U937 cells increased from 302 mg / g cell protein and87 mg / g cell protein to 469 mg / g cell protein and 226 mg / g cell protein respectively. CD36 protein and mRNA expression appeared. Incubated together with atorvastatin and ox-LDL, the contents of TC and CE decreased from 469 mg / g cell protein and 226 mg / g cell protein to 378 mg / g cell protein and 119 mg / g cell protein, the levels of CD36 protein and mRNA also decreased respectively from 25.8% and 1.27 to 17.2% and0.95 compared with being incubated only with ox-LDL. Conclusion Atorvastatin could inhibit the expression of CD36 protein and mRNA in U937 cells and decrease lipid deposition, which is the important mechanism of anti-atherosclerosis as well as lowering blood lipid.

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.

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.

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.

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.

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.

Effects of microstructure on uniaxial strength asymmetry of open-cell foams

Based on the elongated Kelvin model, the effect of microstructure on the uniaxial strength asymmetry of open-cell foams is investigated. The results indicate that this asymmetry depends on the relative density, the solid material, the cell morphology, and the strut geometry of open-cell foams. Even though the solid material has the same tensile and compressive strength, the tensile and compressive strength of open-cell foams with asymmetrical sectional struts are still different. In addition, with the increasing degree of anisotropy, the uniaxial strength as well as the strength asymmetry increases in the rise direction but reduces in the transverse direction. Moreover, the plastic collapse ratio between two directions is verified to depend mainly on the cell morphology. The predicted results are compared with Gibson and Ashby＇s theoretical results as well as the experimental data reported in the literature, which validates that the elongated Kelvin model is accurate in explaining the strength asymmetry presented in realistic open-cell foams.

Analysis and simulation for tensile behavior of anisotropic open-cell elastic foams

Based on the elongated Kelvin obtained to investigate the tensile behavior Kelvin model＇s periodicity and symmetry in model, a simplified periodic structural cell is of anisotropic open-cell elastic foams due to the whole space. The half-strut element and elastic deflection theory are used to analyze the tensile response as done in the previous studies. This study produces theoretical expressions for the tensile stress-strain curve in the rise and transverse directions. In addition, the theoretical results are examined with finite element simulation using an existing formula. The results indicate that the theoretical analysis agrees with the finite element simulation when the strain is not too high, and the present model is better. At the same time, the anisotropy ratio has a significant effect on the mechanical properties of foams. As the anisotropy ratio increases, the tensile stress is improved in the rising direction but drops in the transverse direction under the same strain.

Sound absorption and insulation property of closed-cell aluminum foam

The closed-cell aluminum foams (specimenρ=0.31 g/cm3, diameter of 100 mm, and thickness of 20 mm for sound absorption testing; specimenρ=0.51 g/cm3, length of 1 240 mm, width of 1 100 mm, and thickness of 30 mm for sound insulation testing) were prepared by the method of molten body transitional foaming process. Its sound absorption property under frequency of 160-2 000 Hz and the sound insulation property under frequency of 100-4 000 Hz were tested. The sound absorption results show that the sound absorption property is much better under middle frequencies than that under low and high frequencies. The sound absorption coefficient climbs when frequency increases from 160 Hz to 800 Hz and then drops when frequency is increased from 800 Hz to 2 000 Hz. The function of the sound absorption mainly depends on the Helmholtz resonator, the microphone as well as cracks of closed-cell aluminum foam. The sound insulation experiments show that the sound reduction index (R) is small under low frequencies, and large under high frequencies; the weighted sound reduction index (Rw) and the highest sound reduction index (R) can reach around 30.8 dB and 43 dB, respectively.

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.