Influence of hydrothermal aging on the shear bond strength of 3D printed denture-base resin to different relining materials.

OBJECTIVES: This study evaluated the repairability of three-dimensional printed (3DP) denture bases based on different conventional relining materials and aging. MATERIAL AND METHODS: The groups for surface characterization (surface-roughness and contact-angle measurements) were divided based on the denture base and surface treatment. Shear bond strength test and failure-mode analysis were conducted by a combination of three variables: denture base, relining materials, and hydrothermal aging (HA). The initial characterization involved quantifying the surface roughness (n = 10) and contact angle (n = 10) of denture base specimens with and without sandblasting (SB) treatment. Four relining materials (Kooliner [K], Vertex Self-Curing [V], Tokuyama Rebase II (Normal) [T], and Ufi Gel Hard [U]) were applied to 3DP, heat-cured (HC), and self-cured (SC) denture-base resin specimens. Shear bond strength (n = 15) and failure-mode analyses (n = 15) were performed before and after HA, along with evaluations of the fractured surfaces (n = 4). Statistical analyses were performed using a two-way analysis of variance (ANOVA) for surface characterization, and a three-way ANOVA was conducted for shear bond strength. RESULTS: The surface roughness peaked in HC groups and increased after SB. The 3DP group displayed significantly lower contact angles, which increased after treatment, similar to the surface roughness. The shear bond strength was significantly lower for 3DP and HC denture bases than for SC denture bases, and peaked for U at 10.65 ± 1.88 MPa (mean ± SD). HA decreased the shear bond strength relative to untreated samples. Furthermore, 3DP, HC, and SC mainly showed mixed or cohesive failures with V, T, and U. K, on the other hand, trended toward adhesive failures when bonded with HC and SC. CONCLUSION: This study has validated the repairability of 3DP dentures through relining them with common materials used in clinical practice. The repairability of the 3DP denture base was on par with that of conventional materials, but it decreased after aging. Notably, U, which had a postadhesive application, proved to be the most effective material for repairing 3DP dentures.

Effects of washing solution temperature on the biocompatibility and mechanical properties of 3D-Printed dental resin material.

The use of digital manufacturing, particularly additive manufacturing using three-dimensional (3D) printing, is expanding in the field of dentistry. 3D-printed resin appliances must undergo an essential process, post-washing, to remove residual monomers; however, the effect of the washing solution temperature on the biocompatibility and mechanical properties remains unclear. Therefore, we processed 3D-printed resin samples under different post-washing temperatures (without temperature control (N/T), 30 °C, 40 °C, and 50 °C) for different durations (5, 10, 15, 30, and 60 min) and evaluated the degree of conversion rate, cell viability, flexural strength, and Vickers hardness. Increasing the washing solution temperature significantly improved the degree of conversion rate and cell viability. Conversely, increasing the solution temperature and time decreased the flexural strength and microhardness. This study confirmed that the washing temperature and time influence the mechanical and biological properties of the 3D-printed resin. Washing 3D-printed resin at 30 °C for 30 min was most efficient to maintain optimal biocompatibility and minimize changes of mechanical properties.

Effects of Post-Curing Light Intensity on the Mechanical Properties and Three-Dimensional Printing Accuracy of Interim Dental Material.

This study evaluated the effects of the light intensity of curing and the post-curing duration on the mechanical properties and accuracy of the interim dental material. After designing the specimen, 3D printing was performed, and the light intensity was divided into groups G20, G60, G80, and G120 (corresponding to 1.4−1.6, 2.2−3.0, 3.8−4.4, and 6.4−7.0 mW/cm2, respectively), with no post-curing or 5, 10, or 20 min of post-curing being performed. The flexural properties, Vickers microhardness, degree of conversion (DC), and 3D accuracy were then evaluated. The flexural properties and Vickers microhardness showed a sharp increase at the beginning of the post-curing and then tended to increase gradually as the light intensity and post-curing time increased (p < 0.001). On the other hand, there was no significant difference between groups in the accuracy analysis of a 3D-printed three-unit bridge. These results indicate that the light intensity of the post-curing equipment influences the final mechanical properties of 3D-printed resin and that post-curing can be made more efficient by optimizing the light intensity and post-curing time.

Antibody-Based Targeting of Interferon-Beta-1a Mutein in HER2-Positive Cancer Enhances Antitumor Effects Through Immune Responses and Direct Cell Killing.

Type I interferon (IFN) has been approved as an anticancer agent to treat some malignancies. However, IFNs have a short in vivo half-life, systemic toxicity, and poor biophysical properties, which prevent it from being widely used for cancer therapy. This study aimed to construct recombinant IFN-ß-1a mutein immunocytokines that comprise a human epidermal growth factor receptor 2 (HER2)-targeting antibody and IFN-ß muteins with an additional glycosylation, which can overcome the limitation of the cytokine itself. Hence, the molecular design aims to 1) enhance productivity and biophysical properties by adding secondary glycosylation in IFN-ß, 2) increase the therapeutic index of IFN-ß therapy by preferential retention at the tumor by possessing high affinity for HER2-expressing cancer cells, and 3) improve the pharmacokinetics and, thus, the convenience of IFN-ß administration. The yield of trastuzumab-IFN-ß mutein was higher than that of trastuzumab-wild-type IFN-ß in the mammalian cell culture system. Trastuzumab-IFN-ß mutein showed similar IFN activity and HER2-targeting ability equivalent to that of IFN-ß mutein and trastuzumab, respectively. Trastuzumab-IFN-ß mutein directly inhibited the growth of HER2-positive gastric cancer cell lines and was more effective than trastuzumab or IFN-ß mutein alone. Trastuzumab-IFN-ß mutein and IFN-ß mutein displayed enhanced immune cell-mediated cytotoxicity. Collectively, trastuzumab-IFN-ß mutein may have indirect immune cell-mediated antitumor effects and direct cell growth inhibitory effects. Tumor-targeting effect of trastuzumab-IFN-ß mutein was analyzed using in vivo fluorescence imaging. The accumulation of trastuzumab-IFN-ß mutein was observed in HER2-positive tumors rather than other tissues except the liver. To evaluate the both direct tumor growth inhibition effect and indirect immune cell-mediated antitumor effect, we tested the effect of trastuzumab-IFN-ß mutein in HER2-positive cancer xenograft models using nude mice or humanized mice. Trastuzumab-IFN-ß mutein could significantly enhance tumor regression when compared with trastuzumab or IFN-ß mutein. In addition, an increase in tumor-infiltrating lymphocytes was observed in the trastuzumab-IFN-ß mutein-treated group, implying that the tumor-targeting IFN-ß may have an enhanced antitumor effect through increased immune response. Therefore, targeting IFN-ß with an anti-HER2 monoclonal antibody makes the immunocytokine more potent than either agent alone. These novel findings suggest that trastuzumab-IFN-ß mutein merits clinical evaluation as a new candidate of anticancer therapeutics.

Synthesis and Characterization of Novel Triarylmethane-Based Dyes for Thermally Stable Blue Color Filters.

Two new triarylmethane-based dye molecules with a dimeric structure, TAM-1 and TAM-2, were designed and synthesized as potential blue color filter materials for liquid-crystal displays. The dimeric structure of TAM-1 was designed to improve the thermal stability of a well-known blue dye, Victoria Blue BO. TAM-2 was designed to further improve the solubility of TAM-1 by introducing long alkyl ester groups. The synthesized dyes TAM-1 and TAM-2 were transmissive in the wavelength range of 410-460 nm and showed good thermal stability with 5% weight degradation temperatures (T5d) of 259 °C and 289 °C, respectively, and less than 1% of weight loss at 230 °C. Moreover, TAM-2 showed excellent solubility (20.1 wt%) as opposed to Victoria Blue BO (0.03 wt%) and TAM-1 (3.5 wt%) in PGMEA.

Binge Alcohol Intake After Hypergravity Stress Sustainably Decreases AMPK and Transcription Factors Necessary for Hepatocyte Survival.

BACKGROUND: Binge alcohol consumption elicits mitochondrial dysfunction in hepatocytes. An understanding of the effect of ethanol (EtOH) exposure after hypergravity stress on liver function may assist in the implementation of pathophysiological countermeasures for aerospace missions. This study investigated whether a combination of hypergravity stress and binge alcohol intake has a detrimental effect on AMP-activated protein kinase (AMPK) and other molecules necessary for hepatocyte survival. METHODS: The mice were orally administered a single dose of EtOH (5 g/kg body weight, 20% EtOH) immediately after a load to +9 Gz hypergravity for 1 hour using a small animal centrifuge and sacrificed 24 hours after treatment. For the multiple-dose model, 3 consecutive daily treatments were carried out. Immunoblottings were carried out on liver homogenates. RESULTS: Binge alcohol intake in mice immediately after a 1-hour exposure to a +9 Gz hypergravity load repressed hepatic Akt and PARP-1 levels at 24 hours posttreatment. Moreover, it sustainably diminished the level of AMPKα, a key regulator of energy metabolism, as compared to each individual treatment. Similarly, the combination of alcohol and hypergravity suppressed the levels of STAT3, FOXO1/3, C/EBPß, and CREB, transcription factors necessary for cell survival. Similar changes were not detected after 3 consecutive daily combinatorial treatments, indicating that repetitive training with hypergravity loads provides hepatoprotective effects in a binge alcohol model. CONCLUSIONS: These results show that binge alcohol exposure in mice immediately following a +9 Gz hypergravity stress persistently decreased AMPKα and other key molecules required for hepatocyte survival, and these changes may be reversed by repetitive hypergravity loads.

A load of mice to hypergravity causes AMPKα repression with liver injury, which is overcome by preconditioning loads via Nrf2.

An understanding of the effects of hypergravity on energy homeostasis is necessary in managing proper physiological countermeasures for aerospace missions. This study investigated whether a single or multiple load(s) of mice to hypergravity has an effect on molecules associated with energy metabolism. In the liver, AMPKα level and its signaling were repressed 6 h after a load to +9 Gz hypergravity for 1 h, and then gradually returned toward normal. AMPKα level was restored after 3 loads to +9 Gz, suggestive of preconditioning adaptation. In cDNA microarray analyses, 221 genes were differentially expressed by +9 Gz, and the down-regulated genes included Nrf2 targets. Nrf2 gene knockout abrogated the recovery of AMPKα elicited by 3 loads to +9 Gz, indicating that Nrf2 plays a role in the adaptive increase of AMPKα. In addition, +9 Gz stress decreased STAT3, FOXO1/3 and CREB levels, which was attenuated during the resting time. Similarly, apoptotic markers were enhanced in the liver, indicating that the liver may be vulnerable to hypergravity stress. Preconditioning loads prevented hepatocyte apoptosis. Overall, a load of mice to +9 Gz hypergravity causes AMPKα repression with liver injury, which may be overcome by multiple loads to hypergravity as mediated by Nrf2.

Etoposide Induces Necrosis Through p53-Mediated Antiapoptosis in Human Kidney Proximal Tubule Cells.

The p53 protein is an important transcription factor that modulates signaling pathways for both cell death and survival. Its antiapoptotic mechanisms that correlate with necrotic and apoptotic cell death are not well understood. Here, we report that etoposide promotes progression of the DNA damage response as well as necrotic morphological changes including plasma membrane rupture using carbon nanotube-tipped/atomic force microscopy (CNT/AFM) probes in human kidney proximal tubule (HK-2) cells. Inhibition of p53 abrogated cell cycle arrest and led to a decrease in the expression levels of repair proteins that were induced by DNA damage. Mitochondrial biogenesis and cytosolic production of reactive oxygen species were also reduced after p53 inhibition; the latter change induced mitochondrial superoxide accumulation and mitochondrial damage, which triggered the activation of caspase 3. Inhibition of p53 also led to a loss of cell adhesion and converted necrotic cell death to apoptotic cell death, with appreciable cell shrinkage and appearance of apoptotic bodies that were observed using CNT/AFM probes. Thus, our study demonstrated that p53 protects against apoptosis, and leads to etoposide-induced necrosis. These results are expected to aid in the understanding of mechanism of antiapoptosis and its relationship to cell death.

Gα12 overexpressed in hepatocellular carcinoma reduces microRNA-122 expression via HNF4α inactivation, which causes c-Met induction.

MicroRNA-122 (miR-122) is implicated as a regulator of physiological and pathophysiological processes in the liver. Overexpression of Gα12 is associated with overall survival in patients with hepatocellular carcinoma (HCC). Array-based miRNA profiling was performed on Huh7 stably transfected with activated Gα12 to find miRNAs regulated by the Gα12 pathway; among them, miR-122 was most greatly repressed. miR-122 directly inhibits c-Met expression, playing a role in HCC progression. Gα12 destabilized HNF4α by accelerating ubiquitination, impeding constitutive expression of miR-122. miR-122 mimic transfection diminished the ability of Gα12 to increase c-Met and to activate ERK, STAT3, and Akt/mTOR, suppressing cell proliferation with augmented apoptosis. Consistently, miR-122 transfection prohibited tumor cell colony formation and endothelial tube formation. In a xenograft model, Gα12 knockdown attenuated c-Met expression by restoring HNF4α levels, and elicited tumor cell apoptosis but diminished Ki67 intensities. In human HCC samples, Gα12 levels correlated to c-Met and were inversely associated with miR-122. Both miR-122 and c-Met expression significantly changed in tumor node metastasis (TNM) stage II/III tumors. Moreover, changes in Gα12 and miR-122 levels discriminated recurrence-free and overall survival rates of HCC patients. Collectively, Gα12 overexpression in HCC inhibits MIR122 transactivation by inactivating HNF4α, which causes c-Met induction, contributing to cancer aggressiveness.

Phytochemical regulation of Fyn and AMPK signaling circuitry.

During the past decades, phytochemical terpenoids, polyphenols, lignans, flavonoids, and alkaloids have been identified as antioxidative and cytoprotective agents. Adenosine monophosphate-activated protein kinase (AMPK) is a kinase that controls redox-state and oxidative stress in the cell, and serves as a key molecule regulating energy metabolism. Many phytochemicals directly or indirectly alter the AMPK pathway in distinct manners, exerting catabolic metabolism. Some of them are considered promising in the treatment of metabolic diseases such as type II diabetes, obesity, and hyperlipidemia. Another important kinase that regulates energy metabolism is Fyn kinase, a member of the Src family kinases that plays a role in various cellular responses such as insulin signaling, cell growth, oxidative stress and apoptosis. Phytochemical inhibition of Fyn leads to AMPK-mediated protection of the cell in association with increased antioxidative capacity and mitochondrial biogenesis. The kinases may work together to form a signaling circuitry for the homeostasis of energy conservation and expenditure, and may serve as targets of phytochemicals. This review is intended as a compilation of recent advancements in the pharmacological research of phytochemicals targeting Fyn and AMPK circuitry, providing information for the prevention and treatment of metabolic diseases and the accompanying tissue injuries.

Phlda3, a urine-detectable protein, causes p53 accumulation in renal tubular cells injured by cisplatin.

Measurable indicators of renal injury are required for the assessment of kidney function after toxicant challenge. In our previous study, pleckstrin homology-like domain, family A, member 3 (Phlda3) was a most greatly up-regulated molecule downstream from p53, culminating with kidney tubular injury. This study investigated the positive feedforward effect of Phlda3 on p53 in an effort to explain the largest increase of Phlda3 in injured tubules and the potential of its urine excretion. qRT-PCR assays confirmed a rapid and substantial increase in Phlda3 messenger RNA (mRNA) in the kidney cortex of mice treated with a single dose of cisplatin. Cisplatin overexpression of Phlda3 was verified by gene set analyses of three different microarray databases. In the immunohistochemistry, Phlda3 staining intensities were augmented in the tubules as kidney injury worsened. Moreover, the urinary content of Phlda3 was increased after cisplatin treatment, as were those of other kidney injury markers (Kim-1 and Timp-1). By contrast, cisplatin failed to increase Phlda3 mRNA in the liver despite hepatocyte necrosis and ensuing increases in serum transaminase activities. In NRK52E tubular cells, siRNA knockdown of Phlda3 enhanced the ability of cisplatin to increase p-Mdm2 presumably via Akt, enforcing the interaction between Mdm2 and p53. Consistently, a deficiency in Phlda3 abrogated p53 increase by cisplatin, indicating that Phlda3 promotes p53 accumulation. Phlda3 overexpression had the opposite effect. In addition, treatment with cyclosporine A or CdCl2, other nephrotoxicants, increased Phlda3 mRNA and protein levels in NRK52E cells, as did cisplatin treatment. Overall, Phlda3 may cause p53 accumulation through a feedforward pathway, facilitating tubular injury and its urine excretion.

Increase of miR-199a-5p by protoporphyrin IX, a photocatalyzer, directly inhibits E2F3, sensitizing mesenchymal tumor cells to anti-cancer agents.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths. Protoporphyrin IX (PPIX) has been used for photodynamic therapy. Mesenchymal cancer cells adapt to tumor microenvironments for growth and metastasis possibly in association with miRNA dysregulation. In view of the effect of PPIX on cancer-related genes, and its potential to inhibit tumor growth and migration/invasion, this study investigated whether PPIX enables mesenchymal liver tumor to restore dysregulated miRNAs, and if so, whether it sensitizes the cancer cells to chemotherapy. In addition, we explored new target(s) of the miRNA(s) that contribute to the anti-cancer effects. Of the ten miRNAs predicted by the 3'-UTR of HIF-1α mRNA, PPIX treatment increased miR-199a-5p, leading to the inhibition of E2F3 expression which is upregulated in mesenchymal liver tumor. miR-199a-5p levels were downregulated in HCC with E2F3 overexpression. An approach modulating epithelial-mesenchymal transition provided the expected changes in miR-199a-5p and E2F3 in vivo. PPIX prevented tumor cell growth and migration/invasion, and had a synergistic anti-cancer effect when combined with chemotherapeutics. In a xenograft model, PPIX treatment decreased overall growth and average tumor volume, which paralleled E2F3 inhibition. Overall, PPIX inhibited growth advantage and migratory ability of cancer cells and sensitized mesenchymal liver tumor cells to chemotherapeutics.

Specific oligopeptides in fermented soybean extract inhibit NF-κB-dependent iNOS and cytokine induction by toll-like receptor ligands.

The ethanol extract of fermented soybean from Glycine max (chungkookjang, CHU) has been claimed to have chemopreventive and cytoprotective effects. In the present study, we examined the inhibitory effect of CHU on inducible nitric oxide synthase (iNOS) and cytokine induction by toll-like receptor (TLR) ligands treatment and attempted to identify the responsible active components. Nitric oxide (NO) content and iNOS levels in the media or RAW264.7 cells were measured using the Griess reagent and real-time polymerase chain reaction assays. CHU treatment inhibited NO production and iNOS induction elicited by lipopolysaccharide (LPS, TLR4L) in a concentration-dependent manner. Tumor necrosis factor-α and interleukin-6 productions were also diminished. Peptidoglycans (TLR2/6L) and CpG-oligodeoxynucleotides (TLR9L) from CHU inhibited iNOS induction, but not poly I:C (TLR3L) or loxoribine (TLF7L). The anti-inflammatory effect resulted from the inhibition of nuclear factor-kappa B (NF-κB) through the inhibition of inhibitory-κB degradation. Of the representative components in CHU, specific oligopeptides (AFPG and GVAWWMY) had the ability to inhibit iNOS induction by LPS, whereas others failed to do so. Daidzein, an isoflavone used for comparative purposes, was active at a relatively higher concentration. In an animal model, oral administration of CHU to rats significantly diminished carrageenan-induced paw edema and iNOS induction. Our results demonstrate that CHU has anti-inflammatory effects against TLR ligands by inhibiting NF-κB activation, which may result from specific oligopeptide components in CHU. Since CHU is orally effective, dietary applications of CHU and/or the identified oligopeptides may be of use in the prevention of inflammatory diseases.

Discovery of an integrative network of microRNAs and transcriptomics changes for acute kidney injury.

The contribution of miRNA to the pathogenesis of acute kidney injury (AKI) is not well understood. Here we evaluated an integrative network of miRNAs and mRNA data to discover a possible master regulator of AKI. Microarray analyses of the kidneys of mice treated with cisplatin were used to extract putative miRNAs that cause renal injury. Of them, miR-122 was mostly downregulated by cisplatin, whereas miR-34a was upregulated. A network integrating dysregulated miRNAs and altered mRNA expression along with target prediction enabled us to identify Foxo3 as a core protein to activate p53. The miR-122 inhibited Foxo3 translation as assessed using an miR mimic, an inhibitor, and a Foxo3 3'-UTR reporter. In a mouse model, Foxo3 levels paralleled the degree of tubular injury. The role of decreased miR-122 in inducing Foxo3 during AKI was strengthened by the ability of the miR-122 mimic or inhibitor to replicate results. Increase in miR-34a also promoted the acetylation of Foxo3 by repressing Sirt1. Consistently, cisplatin facilitated the binding of Foxo3 and p53 for activation, which depended not only on decreased miR-122 but also on increased miR-34a. Other nephrotoxicants had similar effects. Among targets of p53, Phlda3 was robustly induced by cisplatin, causing tubular injury. Consistently, treatment with miR mimics and/or inhibitors, or with Foxo3 and Phlda3 siRNAs, modulated apoptosis. Thus, our results uncovered an miR integrative network regulating toxicant-induced AKI and identified Foxo3 as a bridge molecule to the p53 pathway.

Mitigation of carbon tetrachloride-induced hepatic injury by methylene blue, a repurposed drug, is mediated by dual inhibition of GSK3ß downstream of PKA.

BACKGROUND AND PURPOSE: Methylene blue (MB) has recently been considered for new therapeutic applications. In this study, we investigated whether MB has antioxidant and mitochondria-protecting effects and can prevent the development of toxicant-induced hepatitis. In addition, we explored the underlying basis of its effects. EXPERIMENTAL APPROACH: Blood biochemistry and histopathology were assessed in mice injected with CCl4 (0.5 mL·kg(-1)) following MB administration (3 mg·kg(-1) ·day(-1), 3 days). Immunoblottings were performed to measure protein levels. Cell survival, H2 O2 , and mitochondrial superoxide and membrane permeability transition were determined in HepG2 cells. KEY RESULTS: MB protected cells from oxidative stress induced by arachidonic acid plus iron; it restored GSH content and decreased the production of H2 O2 . It consistently attenuated mitochondria dysfunction, as indicated by inhibition of superoxide production and mitochondrial permeability transition. MB inhibited glycogen synthase kinase-3ß (GSK3ß) and protected the liver against CCl4. Using siRNA, the inhibition of GSK3ß was shown to depend on AMPK. MB increased the activation of AMPK in vitro (3-24 h) and in vivo. MB also increased the phosphorylation of liver kinase B1 (LKB1) via cAMP-dependent PKA. SiRNA knockdown of LKB1 eliminated phosphorylation of AMPK and inhibited MB activation of AMPK. In addition, MB treatment (≤1 h) facilitated PKA-mediated GSK3ß serine phosphorylation independently of AMPK. CONCLUSIONS AND IMPLICATIONS: MB has antioxidant and mitochondria-protecting effects and protects the liver from toxicants, which results from the dual inhibition of GSK3ß by AMPK downstream of PKA-activated LKB1, and PKA itself. Our findings reveal a novel pharmacological effect of MB and its molecular basis.

Detection and determination of solute carbon in grain interior to correlate with the overall carbon content and grain size in ultra-low-carbon steel.

In this study, every effort was exerted to determine and accumulate data to correlate microstructural and compositional elements in ultra-low-carbon (ULC) steels to variation of carbon content (12-44 ppm), manganese (0.18-0.36%), and sulfur (0.0066-0.001%). Quantitative analysis of the ULC steel using optical microscope, scanning electron microscope, transmission electron microscope, and three-dimensional atom probe revealed the decrease of grain size and dislocation density with the increase of carbon contents and/or increase of the final delivery temperature. For a given carbon content, the grain interior carbon concentration increases as the grain size increases.

An active metabolite of oltipraz (M2) increases mitochondrial fuel oxidation and inhibits lipogenesis in the liver by dually activating AMPK.

BACKGROUND AND PURPOSE: Oltipraz, a cancer chemopreventive agent, has an anti-steatotic effect via liver X receptor-α (LXRα) inhibition. Here we have assessed the biological activity of a major metabolite of oltipraz (M2) against liver steatosis and steatohepatitis and the underlying mechanism(s). EXPERIMENTAL APPROACH: Blood biochemistry and histopathology were assessed in high-fat diet (HFD)-fed mice treated with M2. An in vitroHepG2 cell model was used to study the mechanism of action. Immunoblotting, real-time PCR and luciferase reporter assays were performed to measure target protein or gene expression levels. KEY RESULTS: M2 treatment inhibited HFD-induced steatohepatitis and diminished oxidative stress in liver. It increased expression of genes encoding proteins involved in mitochondrial fuel oxidation. Mitochondrial DNA content and oxygen consumption rate were enhanced. Moreover, M2 treatment repressed activity of LXRα and induction of its target genes, indicating anti-lipogenic effects. M2 activated AMP-activated protein kinase (AMPK). Inhibition of AMPK by over-expression of dominant negative AMPK (DN-AMPK) or by Compound C prevented M2 from inducing genes for fatty acid oxidation and repressed sterol regulatory element binding protein-1c (SREBP-1c) expression. M2 activated liver kinase B1 (LKB1) and increased the AMP/ATP ratio. LKB1 knockdown failed to reverse target protein modulations or AMPK activation by M2, supporting the proposal that both LKB1 and increased AMP/ATP ratio contribute to its anti-steatotic effect. CONCLUSION AND IMPLICATIONS: M2 inhibited liver steatosis and steatohepatitis by enhancing mitochondrial fuel oxidation and inhibiting lipogenesis. These effects reflected activation of AMPK elicited by increases in LKB1 activity and AMP/ATP ratio.

Enhanced antioxidant effect of prenylated polyphenols as Fyn inhibitor.

Polyphenols have antioxidant effects. In view of the diverse biological activities of prenylated natural products, this study investigated whether polyphenols with prenyl residues have improved antioxidant and cytoprotective activity against oxidative stress, and explored the underlying basis for this effect. A set of structurally related polyphenols exhibited varying degrees of antioxidant effect in HepG2 cells, as evidenced by increases in cell viability against oxidative injury; kazinol E and C with three prenyls had greater potency than other kazinols having fewer prenyl chains. Polyphenols without prenyl (tupichinol C and resveratrol) showed weaker potency. Treatment with kazinol E diminished H(2)O(2) production and enabled cells to protect the mitochondria, as indicated by the inhibition of mitochondrial fragmentation, mitochondrial permeability transition, and cytochrome c release. Moreover, kazinol E activated LKB1 by its phosphorylation and cytoplasmic translocation, contributing to the protection of mitochondria via AMPK. In vitro or in a cell-based assay, tyrosine phosphorylation of Fyn was prohibited by kazinol E, which led to LKB1 activation, as shown by the experiments using Fyn over-expression construct or siRNA. SU6656, a known Fyn inhibitor, had a similar effect. Moreover, oxidative stress facilitated Fyn phosphorylation with repression of AMPKα and GSK3ß phosphorylation, which was abolished by kazinol E treatment. The role of Fyn inhibition by kazinol E in AMPK-mediated protection of the cell viability and mitochondrial function was strengthened by ectopically expressed Fyn's reversal of these effects. In conclusion, kazinols as multi-prenylated polyphenols possess increased antioxidant and cytoprotective activity, which depends on the activation of LKB1-AMPK pathway downstream of Fyn inhibition.

Study on the microstructures and the magnetic properties of precipitates in a Cu75-Fe5-Ni20 alloy.

The microstructural evolutions of precipitates formed in a Cu75-Fe5-Ni20 alloy on isothermal annealing at 873 K and 1073 K have been investigated by means of transmission electron microscopy (TEM). Nano-scale magnetic particles were formed randomly in the Cu-rich matrix after receiving a short annealing due to phase decomposition in the alloy. With increasing the isothermal annealing time, however, the striking features that two or more nano-scale particles with a cubic shape and a rod shape were aligned linearly along (100) directions were observed on isothermal annealing at 873 K and 1073 K, respectively. To investigate electro-magnetic properties of precipitates in a Cu-Fe-Ni alloy, the superconducting quantum interference device (SQUID) magnetometer and physical property measurement system (PPMS) were also complemented. The present study revealed significant influences that the magnetic properties of the specimens were closely related to the microstructures in the Cu-Fe-Ni alloy, which microstructures significantly depend on the isothermal annealing temperature.