Discovery of tissue selective liver X receptor agonists for the treatment of atherosclerosis without causing hepatic lipogenesis.

Liver X Receptor (LXR) is a potential drug target for atherosclerosis. One of the major challenges in taking LXR modulators to the clinic is steatosis. It was reported that sterol LXR agonists selectively activate LXR in the intestine and macrophage cells rather than in the liver. We hypothesize that sterol LXR agonists may selectively inhibit atherosclerosis without causing hepatic lipogenesis. Thus, based on LXR structure, 12 sterol compounds were designed and tested in a dual-luciferase reporter gene experiment. It was confirmed that compounds 4 and 6 were LXR agonists. Further experiments demonstrated that compounds 4 and 6 inhibit the formation of macrophage foam cells without inducing triglyceride accumulation in either hepatocytes or adipocytes. In vivo studies demonstrated that compound 4 promotes reverse cholesterol transport without inducing hepatic lipogenesis. Thus, we report that these compounds with sterol scaffolds can be promising leads for the treatment of atherosclerosis without inducing steatosis.

Pterosin Sesquiterpenoids from Pteris cretica as Hypolipidemic Agents via Activating Liver X Receptors.

Four new pterosin sesquiterpenoids (1-4), a new ent-kaurane diterpenoid (17), and 18 known compounds were isolated from the aerial parts of Pteris cretica L. The structures of the isolates were elucidated based on spectroscopic data analysis, and their absolute configurations were determined by comparison of experimental and calculated electronic circular dichroism spectra. The compounds were evaluated for lipid-lowering effects in 3T3-L1 adipocytes. Compounds 4, 8, 17, and 22 were more potent than the positive control, berberine, in decreasing triglycerides activity, with compound 4 exerting the most potent activity. Compound 4 activated LXRα/ß in a HEK 293T cell-based reporter gene assay. Molecular dynamic simulations revealed that compound 4 activates liver X receptors (LXRs) through hydrogen bonding with the residues of LXRα/ß, suggesting that compound 4 reduces total triglycerides through the regulation of LXRα/ß.

Medical management of chronic kidney disease in the renal transplant recipient.

PURPOSE OF REVIEW: An updated overview of the state-of-the-art approaches to the care of chronic kidney disease-related issues in renal transplant recipients. RECENT FINDINGS: These include the impact of immunosuppression therapy on kidney function, the management of cardiovascular risk, metabolic bone disease, and hematologic complications, with a focus on the care of the patient with a failing allograft. SUMMARY: A kidney transplant improves patient morbidity and mortality, but almost all transplant patients continue to have morbidity related to chronic kidney disease. It is increasingly clear that the provision of adequate immunosuppression is important to preserve allograft function. Recent studies have lent support to current guidelines for the management of cardiovascular risk factors in transplant patients. New data regarding the management of metabolic bone disease are sparse. Erythropoietin replacement may improve outcomes in transplant recipients, but the optimal target hemoglobin level is not known. Cessation of immunosuppression in the failed allograft carries the risk of rejection and allosensitization. New evidence suggests that nephrectomy may reduce mortality in patients with a failed allograft, but likely enhances sensitization in the patient awaiting retransplantation.

Neuromechanical characteristics in the knees of patients who had primary conservative treatment for a torn cruciate ligament and reconstruction afterward.

BACKGROUND/PURPOSE: To compare the neuromechanical characteristics and subjective outcomes for knees of patients with a cruciate ligament tear and reconstruction with those for knees of controls at three time intervals, and to determine correlations between the characteristics and subjective outcomes. METHODS: Ten participants with a cruciate ligament tear and at least a 12-week conservative treatment prior to ligament reconstruction were prospectively measured prior to and 3 months and 6 months after surgery. Ten healthy individuals were recruited as controls. Questionnaire surveys regarding the injured knee were conducted, as were bilateral measurements of root mean square electromyography (EMG), the rate of EMG rise, the median frequency in the vastus medialis of the quadriceps muscles and antagonist coactivation from the semitendinosus muscle, and force capacities, including peak torque, rate of force development, and total works of the knee extension. Correlations between the EMG variables (of the vastus medialis and semitendinosus) and the force capacities, and between the EMG variables and the knee injury and osteoarthritis outcome scores (KOOS), and between force capacities and the KOOS were assessed in the participants with a ligament reconstruction. RESULTS: Pre- and postoperative results of EMG variable and force capacities were lower in both knees of the experimental group participants than in the control group participants (all p < 0.05). Correlations between EMG and force capacities, and between these parameters and the KOOS were found. CONCLUSION: There were bilateral neuromechanical defects in the knees of the participants who had undergone conservative treatment as well as reconstruction after a cruciate ligament tear.

Expression and characterization of a soluble VEGF receptor 2 protein.

OBJECTIVE: To clone and express a truncated, soluble vascular endothelial growth factor receptor 2 (sVEGFR2) possessing the combined-functional domains 1-3 and 5 in eukaryotic cells and to test the inhibitory effects of full length VEGFR2 in vivo. RESULTS: pCMV6-trunctated-rVegfr2 (6100 bp) was successfully cloned. The transfection experiments showed that either pCMV6-truncated-rat-Vegfr2 (pCMV6-truncated-rVegfr2) or pCMV6-rVegfr2 inhibited the expression of intracellular green fluorescent protein, which is usually used as an exogenous transfected reporter gene to determine the transfected efficiency. An analysis of the transfected cells revealed that the amount of full-length VEGFR2 protein in the pCMV6-truncated-rVegfr2 transfected cells was 20% lower than that in the negative control (non-transfected HEK 293 cells). The differences in test results between the transfected and negative control groups were greatest from 24-30 h after transfection; this period was therefore chosen as optimal for collecting culture supernatants. This analysis was highly sensitive for detecting the amount of sVEGFR2 protein expressed and secreted by the cells, and the sVEGFR2 protein content was found to increase by approximately 26% in the transfected cells compared to that in the negative control cells (68.2% ± 1.7% vs. 41.9% ± 2.9%, P = 0.000) and by 18% compared to the negative control cells (68.2% ± 1.7% vs. 50.0% ± 0.5%, P = 0.003). Propidium iodide and Hoechst staining indicated no significant change in the number of HEK293 cells undergoing apoptosis 6 days after pCMV6-trucated-Vegfr2 transfection, compared to the negative control. Soluble VEGFR2 produced by pCMV6-truncated-rVegfr2 inhibited full-length VEGFR2 protein expression in the cell membrane. CONCLUSIONS: This study employed a eukaryotic system to express sVEGFR2. The use of transient transfection technology greatly improved transfect efficiency. Recombinant sVEGFR2 inhibited the effect of endogenous full-length VEGFR2 but was not cytotoxic.

Unusual 9,19 : 24,32-dicyclotetracyclic triterpenoids from Lygodium japonicum.

Lygodipenoids A (1) and B (2), two novel C33 tetracyclic triterpenoids with a new 9,19 : 24,32-dicyclopropane skeleton, were isolated from the whole grass of Lygodium japonicum. Their structures were elucidated by spectroscopic and chemical means. Compounds 1 and 2 were tested in transfected cultured human embryonic kidney 293 HEK293 cells for an agonist assay, and compound 1 was identified as a partial agonist for liver X receptor α.

Hydrothermal carbonization of sugarcane bagasse via wet torrefaction in association with microwave heating.

Hydrothermal carbonization of sugarcane bagasse using wet torrefaction is studied. The biomass is torrefied in water or dilute sulfuric acid solution and microwaves are employed to heat the solutions where the reaction temperature is fixed at 180 °C. The effects of acid concentration, heating time and solid-to-liquid ratio on the performance of wet torrefaction are investigated. It is found that the addition of sulfuric acid and increasing heating time are conducive to carbonizing bagasse. The calorific value of bagasse can be increased up to 20.3% from wet torrefaction. With the same improvement in calorific value, the temperature of wet torrefaction is lower than that of dry torrefaction around 100 °C, revealing that wet torrefaction is a promising method to upgrade biomass as fuel. The calorific value of torrefied biomass can be predicted well based on proximate, elemental or fiber analysis, and the last one gives the best estimation.

Proteomic analysis of Caco-2 cells treated with monacolin K.

Monascus species is an important traditional fermentation fungus used on food. Monacolin K (a secondary metabolite of Monascus, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase) in inhibition of mevalonate synthesis may result in reductions of isoprenoid prenylation in cells. Impairment of protein isoprenoid prenylation has been related to anticancer effect in cancer cells. As a functional food for Monascus, however, the molecular mechanisms responsible for the anti-proliferate effect of monacolin K in cancer cells are not clear. We used proteomic analysis by two-dimensional gel electrophoresis, matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS), tandem mass spectrometry (MS/MS), and database interrogation to separate and identify the proteins of Caco-2 cells treated with monacolin K. The results showed that monacolin K inhibited the proliferation of Caco-2 cells in a dose-dependent manner. The identified proteins in proteomic analysis included anti-oxidation enzymes related to reactive oxygen species stress, cytoskeleton proteins, glycolytic enzymes, and enzymes involved in mediating protein interactions. Furthermore, glutathione S-transferase P 1 and cytoskeleton-8, -18, and -19 revealed a down-regulation in a dose-dependent manner in exposure of Caco-2 cells to monacolin K.

5beta-Cholane activators of the farnesol X receptor.

The farnesoid X receptor (FXR) is activated by bile acids, natural agonists for this nuclear receptor. FXR-target genes play important roles in cholesterol and lipid metabolism. We have found that a series of 5beta-cholanic acid derivatives, even though without a hydroxyl group or any other substituent on the steroidal rings, can activate FXR more potently than hydroxylated bile acids in a reporter gene assay. The most potent compound among these derivatives, N-methyl-5beta-glycocholanic acid (NMGCA), induces the formation of receptor/coactivator complex in a gel-shift assay and also increases the expression of FXR target genes in human hepatoma HepG2 cells. Furthermore, in rats, NMGCA causes hypolipidemic effects as well as induction of the FXR target genes in liver. Our results suggest that NMGCA and its derivatives are important FXR activators in the study of the physiological functions of FXR and are potentially useful as pharmaceutical agents for treatment of cholesterol and lipid-related diseases.

Transcriptional regulation of farnesyl pyrophosphate synthase by liver X receptors.

Liver X receptors (LXRs) are members of the nuclear receptor superfamily that are involved in cholesterol and lipid metabolism. In addition to liver, the brain is another site where LXRs may control cholesterol homeostasis. In the brain, the regulation of cholesterol homeostasis is independent from other parts of the body, and its disturbance is associated with neurodegenerative disorders, such as Alzheimer's disease. We have used PCR-based suppressive subtractive cloning to identify new LXR target genes in brain cells. In this report, we show that farnesyl pyrophosphate synthase (FPPS) is a new target gene for LXR in astrocytes and neurons. Farnesyl pyrophosphate is an obligate intermediate for de novo cholesterol synthesis and a substrate for protein farnesylation. Stimulation of FPPS mRNA synthesis by an LXR agonist, Hypocholamide, was observed in several cell lines from the central nervous system. We identified a single putative direct repeat 4 (DR4) LXR response element in the FPPS promoter. In a reporter gene assay, LXR transactivated a reporter gene bearing a truncated FPPS promoter containing this DR4 cis-element but not if the DR4 element was mutated. Using gel-mobility shift assay, we further demonstrated the direct interaction between the LXR/retinoid X receptor (RXR) heterodimer and the response element. Taken together, our results indicate that LXRs directly regulate FPPS gene expression, and thus may play a role in modulating cholesterol synthesis in the brain.

Lipoproteins produced by ApoE-/- astrocytes infected with adenovirus expressing human ApoE.

We have developed an astrocyte cell culture system that is attractive for the study of apoE structure and its impact on astrocyte lipoproteins and neuronal function. Primary astrocytes from apoE-/- mice were infected with adenovirus expressing apoE3 or apoE4 and the nascent lipoproteins secreted were characterized. The nascent apoE-containing astrocyte particles were predominantly the size of plasma high density lipoprotein (HDL). ApoE4, in contrast to apoE3, appeared to be distributed in two distinct lipoprotein peaks and the apoE4-containing lipoproteins contained significantly more radiolabeled triglyceride. On electron micrographs the astrocyte particles were both discoidal and spherical in shape with a prevalence of stacked discs in apoE3 particles, but single discs and larger spheres in apoE4 particles. The apoE4 discs were significantly wider than apoE3 discs. These properties of the astrocyte lipoproteins are similar to those obtained from apoE isoform transgenic mice. Astrocyte lipoproteins containing apoE3, but not apoE4, stimulated neurite outgrowth in Neuro-2a cells. These studies suggest that the isoform-specific effects of apoE lipoproteins may involve differences in particle size and composition. Finally we demonstrate the usefulness of this system by expressing a truncated apoE3 (delta202-299) mutant and show preliminary data indicating that a liver X receptor agonist promotes HDL output by the astrocytes without an increase in apoE in the media. This cell culture system is more flexible and allows for more rapid expression of apoE mutants.