MiR-26b modulates insulin sensitivity in adipocytes by interrupting the PTEN/PI3K/AKT pathway

BACKGROUND

MicroRNAs (miRNAs) have emerged as epigenetic regulators of metabolism and energy homeostasis. There is a growing body of evidence pointing to miRNAs that have important regulatory roles in insulin sensitivity.

OBJECTIVE

The aim of this work was to explore the expression and mechanism of action of miR-26b in obesity-related insulin resistance (IR) in adipocytes.

METHODS

Quantitative real-time PCR was performed to determine miR-26b expression in obese rodent models, human obesity subjects and insulin-resistant adipocytes. We analysed the roles of miR-26b overexpression and inhibition on glucose uptake in adipocytes. Western blotting was used to detect the levels of protein molecules involved in the phosphoinositide-3-kinase (PI3K) pathway. Bioinformatics and the Dual Luciferase Assay were used to identify the target gene of miR-26b. We assessed the regulatory roles of miR-26b on the phosphatase and tensin homologue (PTEN)/PI3K/AKT pathway and the relationship between miR-26b and the metabolism of human obese subjects.

RESULTS

Levels of miR-26b are reduced in visceral adipose tissue (VAT) in obese rodent models, human obesity and insulin-resistant adipocytes. MiR-26b promotes insulin-stimulated glucose uptake and increases insulin-stimulated glucose transporter type 4 translocation to the plasma membrane in human mature adipocytes. MiR-26b modulates insulin-stimulated AKT activation via inhibition of its target gene, PTEN, and significantly increases insulin sensitivity via the PTEN/PI3K/AKT pathway. The expression level of miR-26b negatively correlates with increasing body mass index and homeostasis model assessment for IR in human obese subjects.

CONCLUSION

Decreased miR-26b expression in VAT may be involved in obesity-related IR by interrupting the PTEN/PI3K/AKT pathway.

Etiology of renal artery stenosis in 2047 patients: a single-center retrospective analysis during a 15-year period in China

Systematic investigation with large sample size of the distribution of etiologies of renal artery stenosis (RAS) is scant in both Western countries and China. We retrospectively analyzed the etiology of RAS in 2047 consecutive inpatients diagnosed with RAS for hypertension at Fuwai Hospital between 1999 and 2014. The number of patients with atherosclerosis was 1668 (81.5%), 259 (12.7%) with Takayasu's arteritis (TA), 86 (4.2%) with fibromuscular dysplasia (FMD), 34 (1.6%) with other causes. There was an obvious increase with age in the proportion of atherosclerotic RAS (P<0.001). In patients aged ⩽40 years (n=319) the predominant etiology of RAS was TA (60.5%), followed by FMD (24.8%). In patients aged >40 years (n=1728) the major cause of RAS was atherosclerosis (94.7%), followed by TA (3.8%).The proportion of TA and FMD in female patients was significantly higher than that in male patients (P<0.001). In female patients aged ⩽40 years (n=215), the top three etiologies of RAS were TA (68.4%), FMD (27.9%) and atherosclerosis (1.4%). The present analysis showed that atherosclerosis, TA and FMD were sequentially the top three causes of RAS in the National Center of China. Age and gender had a significant effect on the distribution of etiologies of RAS.

Coronary artery fistula in adults: evaluation with dual-source CT coronary angiography

OBJECTIVE

To evaluate the clinical value of dual-source CT (DSCT) coronary angiography in the diagnosis of coronary artery fistula (CAF) in adults.

METHODS

A large cohort of 17,548 patients, who underwent DSCT coronary angiography in our hospital between January 2008 and October 2013, were retrospectively reviewed for CAF. The origin, course and drainage site of CAF and coexisting abnormalities were analysed. The conventional angiography results, treatments and follow-up DSCT images were also evaluated.

RESULTS

A total of 33 CAFs from 17,548 patients were detected. The incidence of CAF was 0.19% by DSCT. CAF originating from the left coronary artery (LCA) was found in 14 (42.4%) patients, from right coronary artery (RCA) in 4 (12.1%) cases and from both LCA and RCA in 15 (45.5%) patients. The pulmonary artery was the most common site of drainage (28/33, 84.8%). 8 of the 33 (24.2%) cases were associated with aneurysms. Six cases were associated with coronary artery atherosclerosis. Four patients underwent conventional angiography.

CONCLUSION

Coronary-pulmonary artery fistula in adults was found more often than in previous studies. CAF commonly originates from LCA or both LCA and RCA in adults. DSCT is a robust tool for investigating the origin, course and drainage site of CAF and coexistent abnormalities.

ADVANCES IN KNOWLEDGE

A large adult patient cohort who underwent DSCT angiography was reviewed to assess CAFs. Coronary-pulmonary artery fistula in adults was found more often than in previous studies. CAF was observed to originate from the LCA or both coronary arteries in adults. DSCT could clearly depict the fistula origin, course, drainage site and coexisting abnormalities. Conventional angiography results, treatments and follow-up DSCT images were analysed.

Laser-ablated titania nanoparticles for aqueous processed hybrid solar cells

Titania nanoparticles are produced by laser ablation in liquid in order to initiate functionalization of titania with the polymer for the active layer. By combining these titania nanoparticles and water-soluble poly[3-(potassium-6-hexanoate)thiophene-2,5-diyl] (P3P6T) hybrid solar cells are realized.

Gas storage and separation in a water-stable [CuI5BTT3]4− anion framework comprising a giant multi-prismatic nanoscale cage

A water-stable Cu(i)-based metal–organic framework, featuring a giant multi-prismatic nanoscale cage and high CO₂/N₂ and CO₂/H₂ sorption selectivities, was constructed using the nitrogen-rich ligand of 1,3,5-tris(2H-tetrazol-5-yl)benzene (H₃BTT).

Fabrication of SiO2 incorporated ordered mesoporous TiO2 composite films as functional Pt supports for photo-electrocatalytic methanol oxidation

SiO₂ incorporated ordered mesoporous TiO₂ composite films were fabricated as an active support for methanol oxidation and excellent photoelectrocatalytic activity was obtained, showing great potential application prospects.

Strain dynamics of ultrathin VO₂ film grown on TiO₂ (001) and the associated phase transition modulation

Tuning the metal insulator transition (MIT) behavior of VO2 film through the interfacial strain is effective for practical applications. However, the mechanism for strain-modulated MIT is still under debate. Here we directly record the strain dynamics of ultrathin VO2 film on TiO2 substrate and reveal the intrinsic modulation process by means of synchrotron radiation and first-principles calculations. It is observed that the MIT process of the obtained VO2 films can be modulated continuously via the interfacial strain. The relationship between the phase transition temperature and the strain evolution is established from the initial film growth. From the interfacial strain dynamics and theoretical calculations, we claim that the electronic orbital occupancy is strongly affected by the interfacial strain, which changes also the electron-electron correlation and controls the phase transition temperature. These findings open the possibility of an active tuning of phase transition for the thin VO2 film through the interfacial lattice engineering.

The effect of Astragalus polysaccharide on the Epstein-Barr virus lytic cycle

Effects of a polysacharide from Chinese herbal plant Astragalus membranaceus (APS) on the expression of Epstein-Barr virus (EBV) immediate early proteins Zta, Rta and EA-D in Raji cells were examined. EBV switch from latent to lytic cycle in Raji cells was induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) and sorbol butyrate (SB) and the effects of APS were examined by immunofluorescence, western blotting and flow cytometry. APS in a non-cytotoxic concentration of 30 μg/ml significantly suppressed the expression of Zta, Rta and EA-D during the EBV lytic cycle. Our observations indicate that APS is potentially useful as an anti-EBV drug.

Natriorexigenic effect of DAMGO is decreased by blocking AT1 receptors in the central nucleus of the amygdala

μ-Opioid receptor (μ-OR) activation with agonist [D-Ala², N-Me-Phe⁴, Gly⁵-ol]-enkephalin (DAMGO) in the central nucleus of the amygdala (CeA) induces sodium (0.3M NaCl) intake in rats. The purpose of this study was to examine the effects of pre-injections of losartan (AT1 angiotensin receptor antagonist) into the CeA on 0.3 M NaCl and water intake induced by DAMGO injected bilaterally in the same area in rats submitted to water deprivation-partial rehydration (WD-PR) and in rats treated with the diuretic furosemide (FURO) combined with a low dose of the angiotensin-converting enzyme inhibitor captopril (CAP) injected subcutaneously (FURO/CAP). Male Sprague-Dawley rats with stainless steel cannulas implanted bilaterally into the CeA were used. In WD-PR rats, bilateral injections of DAMGO (2 nmol in 0.5 μL) into the CeA induced 0.3 M NaCl and water intake, and pre-treatment with losartan (108 nmol in 0.5 μL) injected into the CeA reduced 0.3 M NaCl and water intake induced by DAMGO. In FURO/CAP rats, pre-treatment with losartan (108 nmol in 0.5 μL) injected into the CeA attenuated the increase in 0.3M NaCl and water intake induced by DAMGO (2 nmol in 0.5 μL) injected into the same site. The results suggest that the natriorexigenic effect of DAMGO injected into the CeA is facilitated by endogenous angiotensin II acting on AT1 receptors in the CeA, which drives rats to ingest large amounts of hypertonic NaCl.

Effect of CYP1A2 polymorphism on the pharmacokinetics of agomelatine in Chinese healthy male volunteers

WHAT IS KNOWN AND OBJECTIVE

Agomelatine is a melatonin (MT) analogue with agonistic properties and has been proven to be effective for various types of depressive symptoms. Following oral administration, agomelatine is primarily metabolized by the hepatic cytochrome P450 isoenzyme CYP1A2. The purpose of this study was to assess the influence of CYP1A2 single nucleotide polymorphisms (SNPs, rs762551, rs2069514, rs2472304, rs2470890) on agomelatine pharmacokinetics in the Chinese population.

METHODS

Seventy-two healthy Chinese male volunteers enrolled in the study received an oral dose of 25 mg of agomelatine after providing written informed consent. CYP1A2 SNPs were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Agomelatine plasma concentrations were determined by high performance liquid chromatography-tandem mass spectrometry, and the pharmacokinetics analyses were evaluated by nonparametric methods.

RESULTS AND DISCUSSION

After a single oral dose of 25 mg agomelatine, no significant differences existed in agomelatine pharmacokinetics between the rs2069514 GG homozygotes (n = 35) and the rs2069514 AG allele (n = 35) in all subjects. The mean agomelatine AUC0-7 , AUC0-∞ and Cmax for the rs762551 CC homozygotes (n = 9), rs2470890 CC homozygotes (n = 54) and rs2472304 GG homozygotes (n = 51) were much higher than the rs762551 AA allele (n = 31), rs2470890 CT allele (n = 17) and rs2472304 AG allele (n = 20) respectively (P < 0.05).

WHAT IS NEW AND CONCLUSION

The rs762551 A, rs2470890 T and rs2472304 A genotype presented a significantly lower level of agomelatine exposure (AUC, Cmax ) compared with the rs762551 C, rs2470890 C and rs2472304 G genotype in Chinese healthy subjects. It suggested that the rs762551, rs2470890 and rs2472304 genetic polymorphism might be associated with the marked interindividual variability of agomelatine, and the pharmacokinetic profile of agomelatine may be different in different races.

HMGB3 characterization in gastric cancer

Gastric cancer is a major health problem worldwide; it is the second most common cause of cancer death in the world. Recent studies indicate that the high-mobility group (HMG) of chromosomal proteins is associated with cancer progression. However, HMGB3 has been little studied. We analyzed the co-expression network between HMGB3 and differentially-expressed genes in the GSE17187 database, identifying the relevant transcription factors, and the conserved domain of HMGB3 to understand the underlying regulation mechanisms involved in gastric cancer. Thirty-one relationships between 11 differentially-expressed genes were included in a co-expression network; many of these genes have been identified as related to cancer, including TBX5 and TFR2. Further analysis identified nine transcription factors, these being GATA3, MZF1, GATA1, GATA2, SRY, REL, NFYB, NFYC, and NFYA, which could interact with HMGB3 to regulate target gene expression and consequently regulate gastric cancer cell proliferation, migration and invasion. The HMG-box domain was very similar in various species, with only a few amino acid changes, indicating conserved functions in HMG-box. This information helps to provide insight into the molecular mechanisms of HMGB3 in human gastric cancer.

Glucocorticoid downregulates expression of IL-12 family cytokines in systemic lupus erythematosus patients

OBJECTIVE

This study aims to investigate expression of interleukin 12 (IL-12) family cytokines IL-12, IL-23, IL-27 and IL-35 in systemic lupus erythematosus (SLE) patients and the effect of glucocorticoid (GC) treatment on their expression.

METHODS

Plasma concentration of IL-12, IL-23, IL-27, IL-35, IL-6 and anti-double-stranded DNA (dsDNA) antibodies in 30 newly diagnosed severe SLE patients and 30 matched healthy subjects was measured by enzyme-linked immunosorbent assay. The correlation between the levels of IL-12 family cytokines and the levels of IL-6 or anti-dsDNA antibodies was analyzed by Spearman rank correlation.

RESULTS

Significantly higher levels of plasma IL-12, IL-23, IL-27, IL-35, IL-6 and anti-dsDNA antibodies were observed in SLE patients compared with healthy controls (p < 0.05), and after prednisone treatment, the serum levels of IL-12 family cytokines decreased significantly. Moreover, serum levels of IL-12, IL-23, IL-27 and IL-35 were correlated with serum levels of IL-6 and anti-dsDNA antibodies in pre-treatment as well as post-treatment SLE patients.

CONCLUSIONS

SLE patients have increased plasma levels of IL-12 family cytokines and GCs can downregulate the expression of them in SLE patients. Therefore, members of the IL-12 family may be involved in the pathophysiological process of SLE.

Pharmacokinetics and biodistribution study of paclitaxel liposome in Sprague-Dawley rats and Beagle dogs by liquid chromatography-tandem mass spectrometry

Lipusu is the first paclitaxel liposome preparation approved in the world and has been widely used in China for the treatment of ovary, breast and non-small cell lung cancer. In present study we evaluated the pharmacokinetic and tissue distribution characteristics of paclitaxel liposome in Sprague-Dawley rats and Beagle dogs. A rapid and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was developed for the determination of paclitaxel in plasma and tissues. The plasma concentrations of paclitaxel in both rats and dogs initially declined steeply, followed by slow elimination after intravenous administration of Lipusu at 5 mg/kg and 1 mg/kg, respectively. The pharmacokinetic parameters calculated by a non-compartmental method in rats and dogs were as follows: AUC0-24: 3 566.5±1 366.1 and 443.2±165.7 μg · h/L, CL: 1.5±0.5 and 2.1±0.6 L/h/kg, Vd: 20.0±7.8 and 38.4±12.5 L/kg, t1/2: 9.3±2.9 and 14.1±6.9 h, respectively. Biodistribution results in rats showed that except for brain and testis, liposomal paclitaxel was extensively distributed into various tissues, especially highly in liver and spleen.

Aberrant regulation of the integrin very late antigen-4 in systemic lupus erythematosus

Integrin very late antigen-4 (VLA4) is induced during inflammation and can regulate monocyte migration. It has been implicated in atherogenesis, a significant concern in systemic lupus erythematosus (SLE). The aim of this study was to define VLA4 expression in SLE monocytes. Flow cytometry, reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry staining with confocal microscopy were used to evaluate VLA4 expression in SLE patients and controls. We found elevated expression of VLA4 in SLE patients with significantly increased VLA4 staining intracellularly compared to control. Exposure of control monocytes to SLE sera or immune complexes led to increased intracellular expression, and immune complexes were capable of driving redistribution of surface VLA4 to the cytoplasm. Therefore, VLA4 was found to be subject to complex regulation with SLE sera driving both RNA expression and redistribution of protein. Stimulation of SLE monocytes with a VLA4 ligand induced significant TNFα expression, confirming a functional effect. This behavior may contribute to increased atherosclerosis and monocyte infiltrates in end organs.

The roles of mesenchymal stem cells in gastric lesion and regeneration: applications in gastric diseases

In recent years, many studies have focused on the roles of mesenchymal stem cells (MSCs) due to their contribution to tissue regeneration and tumorigenesis. However, the full profile of the roles of MSCs in gastric diseases has not been established. In this review, we aim to provide an overview on the roles of MSCs on cell lesion and regeneration in gastric diseases, including gastric ulcer, premalignant conditions and cancer. We will also discuss the mechanisms underlying the behaviors of MSCs in these diseases.