SIRT1/PGC-1α signaling protects hepatocytes against mitochondrial oxidative stress induced by bile acids

Oxidative stress and mitochondrial dysfunction are hypothesized to contribute to the pathogenesis of chronic cholestatic liver diseases. Silent information regulator 1 (SIRT1) attenuates oxidative stress and improves mitochondrial biogenesis in numerous mitochondrial-related diseases; however, a functional role for SIRT1 in chronic liver cholestasis, characterized by increased levels of toxic bile acids, remains unknown. We show decrease in SIRT1 levels and its activity and impairment of mitochondrial biogenesis in the liver of patients with extrahepatic cholestasis. Moreover, we found that glycochenodeoxycholic acid (GCDCA) stimulated cytotoxicity, disrupted the mitochondrial membrane potential, increased reactive oxygen species production, and decreased mitochondrial mass and mitochondrial DNA content in L02 cells. Consistent with this finding, GCDCA was found to decrease SIRT1 protein expression and activity, thus promoting the deacetylation of peroxisome proliferator-activated receptor gamma, coactivator 1 alpha (PGC-1α), a key enzyme involved in mitochondrial biogenesis and function. Conversely, GCDCA-induced mitochondrial injury was efficiently attenuated by SIRT1 overexpression. In summary, these findings indicate that the loss of SIRT1 may play a crucial role in the pathogenesis of liver damage observed in patients with extrahepatic cholestasis. The findings also indicate that genetic supplementation of SIRT1 can ameliorate GCDCA-induced hepatotoxicity through the activation of PGC-1α-dependent mitochondrial biogenesis.

Sonic hedgehog through Gli2 and Gli3 is required for the proper development of placental labyrinth

Sonic hedgehog (Shh) functions as a conserved morphogen in the development of various organs in metazoans ranging from Drosophila to humans. Here, we have investigated the potential roles and underlying mechanisms of Shh signaling in murine placentation. Immunostaining revealed the abundant expression of the main components of Shh pathway in both the trophectoderm of blastocysts and developing placentas. Disruption of Shh led to impaired vascularogenesis of yolk sac, less branching and malformation of placental labyrinth, thereby leading to a robust decrease in capacity of transplacental passages. Moreover, placenta-specific gene incorporation by lentiviral transduction of mouse blastocysts and blastocyst transplantation robustly knocked down the expression of Gli3 and Gli2 in placenta but not in embryos. Finally, Gli3 knockdown in Shh^−/− placentas partially rescued the defects of both yolk sac and placental labyrinth, and robustly restored the capacity of transplacental passages. Gli2 knockdown in Shh^+/− placentas affected neither the capacity of tranplacental passages nor the vascularogenesis of yolk sac, however, it partially phenocopied the labyrinthine defects of Shh^−/− placentas. Taken together, these results uncover that both Shh/Gli2 and Shh/Gli3 signals are required for proper development of murine placentas and are possibly essential for pregnant maintenance.

NAMPT inhibitor and metabolite protect mouse brain from cryoinjury through distinct mechanisms

Nicotinamide phosphoribosyltransferase (NAMPT) is the key enzyme in the biosynthesis of nicotinamide adenine dinucleotide (NAD). In the brain, NAMPT is primarily expressed in neurons and can prevent neuronal degeneration. NAMPT is also highly expressed in inflammatory cells, and is responsible for their activation. Since inflammation following traumatic brain injury enhances neuronal damage, we assessed the effects of nicotinamide mononucleotide (NMN), the direct NAMPT metabolite, and FK866, a potent NAMPT inhibitor, on brain injury in a cryoinjury mouse model. Twenty-four hours after brain cryoinjury, the density of neuron and the level of NAD decreased. Both NMN and FK866 alleviated the neuronal loss and decreased the lesion volume. NMN prevented the cryoinjury-induced decrease of NAD level, and FK866 decreased it further. On day 14 after cryoinjury, further neuronal loss occurred, astrocytes and Iba1-positive macrophage/microglia activated, and the NAD level increased. At this time-point, NAMPT expression was strongly induced in Iba1-positive macrophages/microglia in the lesion core. NMN and FK866 also alleviated the neuronal loss and decreased the lesion volume. In addition, FK866 significantly attenuated the activation of astrocytes and Iba1-positive macrophages/microglia, and decreased the NAD, while NMN had no such effects. Taken together, both FK866 and NMN attenuate traumatic brain injury. However, FK866 acts via the inhibition of the NAMPT activity in inflammatory cells resulting in the inhibition of inflammation, whereas NMN is effective via replenishing NAD.

Snail1 correlates with patient outcomes in E-cadherin-preserved gastroesophageal junction adenocarcinoma

PURPOSE

The poor prognosis of gastroesophageal junction (GEJ) adenocarcinoma is largely associated with metastasis. We here report the first study to investigate the expression of epithelial-mesenchymal transition (EMT) markers Snail1 and E-cadherin in GEJ adenocarcinoma.

METHODS

Snail1 and E-cadherin were detected by immunohistochemistry in a cohort of 128 patients with surgically resected GEJ adenocarcinoma. We assessed the pathologic and prognostic relevance in all patients and within clinically different preserved E-cadherin and reduced E-cadherin-expressing sub-groups.

RESULTS

Immunoreactivity for Snail1 and E-cadherin was positive in 68 and 43 % of tumors, respectively. Snail1-positive tumors had more frequent lymph node metastasis and advanced tumor stage. E-cadherin expression was highly associated with histological differentiation, tumor size, advanced stage, presence of lymph node metastasis and distant metastasis. Patients with positive E-cadherin expression or negative Snail1 expression had significantly favorable overall survival rate. In E-cadherin-preserved tumors, the expression of Snail1 was related to lymph node metastasis, advanced stage and poor patient outcome. However, Snail1 expression had no statistically significant relationship with clinicopathologic parameters or prognosis in the reduced E-cadherin-expressing sub-group. Multivariate survival analysis identified that tumor stage [hazard ratio (HR) 2.440; 95 % confidence interval (CI) 1.216-4.896; P = 0.012], lymph node metastasis (HR 2.404; 95 % CI 1.188-4.867; P = 0.015) and gender (HR 3.244; 95 % CI 1.568-6.714; P = 0.002) were independent prognostic markers for overall survival.

CONCLUSIONS

Snail1 may act more critically in E-cadherin-positive tumors. Evaluation of Snail1 and E-cadherin in GEJ adenocarcinoma may help in assessing malignant properties and stratifying patients.

Biomechanical study of the funnel technique applied in thoracic pedicle screw replacement

BACKGROUND

Funnel technique is a method used for the insertion of screw into thoracic pedicle.

AIM

To evaluate the biomechanical characteristics of thoracic pedicle screw placement using the Funnel technique, trying to provide biomechanical basis for clinical application of this technology.

METHODS

14 functional spinal units (T6 to T10) were selected from thoracic spine specimens of 14 fresh adult cadavers, and randomly divided into two groups, including Funnel technique group (n = 7) and Magerl technique group (n = 7). The displacement-stiffness and pull-out strength in all kinds of position were tested and compared.

RESULTS

Two fixed groups were significantly higher than that of the intact state (P < 0.05) in the spinal central axial direction, compression, anterior flexion, posterior bending, lateral bending, axial torsion, but there were no significant differences between two fixed groups (P > 0.05). The mean pull-out strength in Funnel technique group (789.09 ± 27.33) was lower than that in Magerl technique group (P < 0.05).

CONCLUSIONS

The Funnel technique for the insertion point of posterior bone is a safe and accurate technique for pedicle screw placement. It exhibited no effects on the stiffness of spinal column, but decreased the pull-out strength of pedicle screw. Therefore, the funnel technique in the thoracic spine affords an alternative for the standard screw placement.

COUP-TFII regulates metastasis of colorectal adenocarcinoma cells by modulating Snail1

BACKGROUND

Chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII, also known as NR2F2) promotes metastasis by functioning in the tumour microenvironment; however, the role of COUP-TFII in colorectal cancer remains unknown.

METHODS

Human colon adenocarcinoma tissues were collected to test COUP-TFII expression. Wound-healing and cell invasion assay were used to evaluate migration and invasion of cells. Chicken ovalbumin upstream promoter-transcription factor II and related protein expression was assessed by immunostaining, immunoblotting and real-time PCR assay. Tamoxifen-inducible COUP-TFII knockout mice were employed to test COUP-TFII functions on colon cancer metastasis in vivo.

RESULTS

Elevated expression of COUP-TFII in colorectal adenocarcinoma tissue correlated with overexpression of the Snail1 transcription factor. High COUP-TFII expression correlated with metastasis and shorter patient survival. Chicken ovalbumin upstream promoter-transcription factor II regulated the migration and invasion of cancer cells. With Snail1, COUP-TFII inhibited expression of adherence molecules such as ZO-1, E-cadherin and β-catenin in colorectal cancer cells. Overexpression of COUP-TFII was required for cancer cells to metastasise in vivo. Chicken ovalbumin upstream promoter-transcription factor II regulated the transcription and expression of Snail1 by directly targeting the Snail1 promoter and regulated associated genes.

CONCLUSIONS

Chicken ovalbumin upstream promoter-transcription factor II was crucial for colorectal cancer metastasis and regulated cell migration and metastasis in conjunction with Snail1. Chicken ovalbumin upstream promoter-transcription factor II was found to be a biomarker associated with patient survival and colorectal cancer metastasis.

Characteristics of patients complaining of halitosis and factors associated with halitosis

OBJECTIVES

To describe the characteristics of patients who visited halitosis clinic and to investigate the factors that may associate with halitosis.

MATERIALS AND METHODS

Nine hundred and eleven patients, who visited halitosis clinic for consultations, underwent organoleptic tests and volatile sulfur compound (VSC) measurements with a portable sulfide monitor. The oral health of patients, including dental caries, oral hygiene, and gingival inflammation status, was assessed. Questionnaires were used to obtain information on demographics, oral hygiene practices, and dietary habits.

RESULTS

Of the 911 patients, more females than males visited the clinic. Patients' age ranged from 18 to 82 years (mean ± s.d.: 40.8 ± 14.1). Almost 30% of patients had complained of halitosis for over 5 years before looking into treatments. Approximately half of the patients self-perceived that they were unable to get close to others. Around 77% of patients had halitosis. Results of multiple logistic regressions for organoleptic scores and VSC values showed that tongue coating and tongue scraping were significantly associated with halitosis (P < 0.05).

CONCLUSIONS

Among these Chinese patients, over three-quarters of patients had halitosis, and negative impacts on social communications were observed. Tongue coating was the most important factor responsible for halitosis.

Effect of 15-hydroxyprostaglandin dehydrogenase gene on the proliferation of gastric cancer cell murine forestomach carcinoma

The aim of the present study was to construct the eukaryotic expression vector pcDNA3.1/15-PGDH. The vector was used to transfect mouse murine forestomach carcinoma (MFC) cancer cells and observe the effects of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) on the proliferation of MFC. pcDNA3.1/15-PGDH was constructed using gene recombination technology and the vector was used to transfect MFC cells to build a stable transfected cell strain. The expression levels of 15-PGDH in the transfected cells were detected using reverse transcription polymerase chain reaction. Optical Density (OD) values were determined using an MTT assay and used to draw cell growth curves. The effects of 15-PGDH on the proliferation of MFC were observed using a clone formation experiment. Following successful transfection by 15-PGDH, the relative expression levels of 15-PGDH in the MFC/15-PGDH cells were significantly higher (1.06±0.08) (P<0.01) compared with the empty plasmid-transfected group (0.22±0.01) and the untransfected group (0.21±0.01). Following transfection by 15-PGDH, cell growth was markedly inhibited. The MTT results showed that on days 4, 6 and 8, the 15-PGDH-transfected group had a low OD on average, which was significantly different (P<0.05) from the empty plasmid-transfected group or the untransfected group. The 15-PGDH-transfected group had a plating efficiency of 18%, and compared with the untransfected group (63%) and the empty plasmid-transfected group (59%), clone formation was significantly inhibited (P<0.01). Results of the present study indicate that transfection by 15-PGDH may significantly inhibit the proliferation and clone formation of MFC cells.

Proliferation and osteo/odontoblastic differentiation of stem cells from dental apical papilla in mineralization-inducing medium containing additional KH(2)PO(4)

OBJECTIVES

Stem cells from the dental apical papilla (SCAPs) can be induced to differentiate along both osteoblast and odontoblast lineages. However, little knowledge is available concerning their differentiation efficiency in osteogenic media containing additional KH2 PO4 .

MATERIALS AND METHODS

Stem cells from the dental apical papilla were isolated from apical papillae of immature third molars and treated with two kinds of mineralization-inducing media, MM1 and MM2, differing in KH2 PO4 concentration. Proliferation and osteo/odontogenic differentiation capacity of MM1/MM2-treated SCAPs were investigated and compared both in vitro and in vivo.

RESULTS

Cell counting and flow cytometry demonstrated that MM2 containing 1.8 mm additional KH2 PO4 significantly enhanced proliferative potential of SCAPs, compared to MM1. Osteo/odontogenic capacity of SCAPs was much better in MM2 medium than in MM1, as indicated by elevated alkaline phosphatase activity, increased calcium deposition and upregulated expression of osteo/odontoblast-specific genes/proteins (for example, runt-related transcription factor 2, osterix, osteocalcin, dentin sialoprotein, and dentin sialophosphoprotein). In vivo transplantation findings proved that SCAPs in MM2 group generated more mineralized tissues, and presented higher expression of osteo/odontoblast-specific proteins (osteocalcin and dentin sialoprotein) than those in the MM1 group.

CONCLUSION

Mineralization-inducing media supplemented with 1.8 mm additional KH2 PO4 significantly enhanced cell proliferation and improved differentiation capacity of SCAPs along osteo/odontogenic cell lineages, compared to counterparts lacking additional KH2 PO4 .

NADPH oxidase inhibition prevents beta cell dysfunction induced by prolonged elevation of oleate in rodents

AIMS/HYPOTHESIS

The activation of NADPH oxidase has been implicated in NEFA-induced beta cell dysfunction. However, the causal role of this activation in vivo remains unclear. Here, using rodents, we investigated whether pharmacological or genetic inhibition of NADPH oxidase could prevent NEFA-induced beta cell dysfunction in vivo.

METHODS

Normal rats were infused for 48 h with saline or oleate with or without the NADPH oxidase inhibitor apocynin. In addition, NADPH oxidase subunit p47(phox)-null mice and wild-type littermate controls were infused with saline or oleate for 48 h. This was followed by measurement of NADPH oxidase activity, reactive oxygen species (ROS) and superoxide imaging and assessment of beta cell function in isolated islets and hyperglycaemic clamps.

RESULTS

Oleate infusion in rats increased NADPH oxidase activity, consistent with increased total but not mitochondrial superoxide in islets and impaired beta cell function in isolated islets and during hyperglycaemic clamps. Co-infusion of apocynin with oleate normalised NADPH oxidase activity and total superoxide levels and prevented beta cell dysfunction. Similarly, 48 h NEFA elevation in wild-type mice increased total but not mitochondrial superoxide and impaired beta cell function in isolated islets. p47(phox)-null mice were protected against these effects when subjected to 48 h oleate infusion. Finally, oleate increased the levels of total ROS, in both models, whereas inhibition of NADPH oxidase prevented this increase, suggesting that NADPH oxidase is the main source of ROS in this model.

CONCLUSIONS/INTERPRETATION

These data show that NADPH-oxidase-derived cytosolic superoxide is increased in islets upon oleate infusion in vivo; and whole-body NADPH-oxidase inhibition decreases superoxide in concert with restoration of islet function.

Reciprocal interaction between intestinal microbiota and mucosal lymphocyte in cynomolgus monkeys after alemtuzumab treatment

It has been known that the gut microbiota plays a central role in shaping normal mucosal immunity, however, little information is available whether the variability of mucosal lymphocytes impacts the commensal flora. Here, we applied a cynomolgus monkey model to characterize the structure and composition of the gut microbiota in response to lymphocyte depletion and to determine their potential association. Molecular profiling of 16S rDNA showed that the intestinal microbiota composition was perturbed after the depletion of mucosal lymphocytes and were recovered following the repopulation. Some specific bacteria from the orders Lactobacillales, Enterobacteriales and Clostridiales, and the genus Prevotella and Faecalibacterium, were primarily responsible for the variations of the gut microbiota after lymphocyte depletion. Interestingly, the species richness of the ileal mucosal microbiota was associated the proportions of TCRαβ+ or TCRγδ+ T cells (p<0.01). We demonstrate for the first time the feature of intestinal microbiota composition after lymphocyte depletion and provide novel evidence that the perturbation of gut microbiota is associated with lymphocyte depletion. It may contribute to understand the relationship between gut commensal microbiota and mucosal immune system. Study results provide insight into biological activity of alemtuzumab in intestinal barrier in organ transplantation.

Downregulation of endogenous intermedin augmented myocardial injury in rats with ischemia/reperfusion

Intermedin (IMD) plays an important regulatory role in cardiovascular function. We aimed to explore the protein expression of IMD and its receptors, calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMPs), and the role of endogenous IMD in myocardial ischemia/reperfusion (I/R) injury in rats. The rat model of I/R was created by ligating cardiac left anterior descending artery. Western blot was used to determine protein expression of CRLR and RAMPs, and radioimmunoassay was used to detect IMD content. Compared with control, protein levels of CRLR and RAMPs in both ischemic and nonischemic region were upregulated at different stages of reperfusion. IMD protein content in nonischemic area myocardium also increased. However, IMD protein content in ischemic area downregulated at 3-, 6-, and 12-h reperfusion. In hypoxia/reoxygenation model of neonatal cardiomyocytes, IMD attenuated myocyte injury, and IMD receptor antagonist IMD17-47 aggravated myocyte impairment by blocking endogenous IMD. In conclusion, the downregulation of IMD at early stage of reperfusion might augment myocardium injury.

[Study on method of tracking the active cells in image sequences based on EKF-PF]

In cell image sequences, due to the nonlinear and nonGaussian motion characteristics of active cells, the accurate prediction and tracking is still an unsolved problem. We applied extended Kalman particle filter (EKF-PF) here in our study, attempting to solve the problem. Firstly we confirmed the existence and positions of the active cells. Then we established a motion model and improved it via adding motion angle estimation. Next we predicted motion parameters, such as displacement, velocity, accelerated velocity and motion angle, in region centers of the cells being tracked. Finally we obtained the motion traces of active cells. There were fourteen active cells in three image sequences which have been tracked. The errors were less than 2.5 pixels when the prediction values were compared with actual values. It showed that the presented algorithm may basically reach the solution of accurate predition and tracking of the active cells.

Influence of the human MIF promoter polymorphism on hepatocellular carcinoma prognosis

Hepatocellular carcinoma (HCC) is one of the most common worldwide malignancies. A relative complete diagnosis system for primary carcinoma of liver has already been established, but the surgical prognosis for HCC, which depends mainly on postoperative pathological classification and data of recurrence and metastasis, lacks valid experimental indicators. Macrophage migration inhibition factor (MIF) is related to many cancers; hence, the polymorphism of MIF genes may be associated with the surgical prognosis of HCC. The purpose of this study was to investigate the relationship between polymorphisms of MIF gene promoter 794CATT (MIF-794CATT) microsatellite repeats and HCC surgical prognosis and evaluate the contribution of polymorphism to the prognosis of hepatectomy. Sequencing was used to identify the MIF-794CATT of 241 patients who had been submitted to HCC surgery. These patients were classified into 2 groups: one with MIF-794CATT high-repetitive-sequence genotypes (7/x+8/x) and one with low-repetitive-sequence genotypes (5/5+5/6+6/6). Five indictors were analyzed: average survival times were compared using the t-test, and tumor-node-metastasis staging, recurrence and metastasis, differentiation grade, and survival rate were compared using the chi-square test. The (7/x+8/x) CATT group had 139 patients and the (5/5+5/6+6/6) CATT group had 102. Significant differences were found in the 5 factors (P = 0.000, 0.008, 0.002, 0.000, and 0.003, respectively). Patients with MIF-794CATT5-8 low-repetitive-sequence genotypes had better prognosis than those with high-repetitive-sequence genotypes. The polymorphism detection of MIF-794CATT microsatellite repeats is valuable for HCC surgical prognosis.

Surface-emission studies in a high-field RF gun based on measurements of field emission and Schottky-enabled photoemission

We report on investigations into the fundamental surface emission parameters, the geometric field enhancement factor (β) and the work function (φ), by making both field emission and Schottky-enabled photoemission measurements. The measurements were performed on a copper surface in the Tsinghua University S-band RF gun in two separate experiments. Fitting our data to the models for each experiment indicate that the traditionally assumed high value of β(≈50-500) does not provide a plausible explanation of the data, but incorporating a low value of φ at some sites does. In addition, direct measurements of the surface conducted after the experiment show that β is on the order of a few, consistent with our understanding of the electron emission measurements. Thus we conclude that the dominant source of electron emission in high gradient RF cavities is due to low φ sites, as opposed to the conventionally assumed high β sites. The origin of low φ at these sites is unclear and should be the subject of further investigation.

Multilayered mucoadhesive hydrogel films based on thiolated hyaluronic acid and polyvinylalcohol for insulin delivery

A multilayered hydrogel film system based on hyaluronic acid-cysteamine (HA-Cym) and polyvinylalcohol (PVA) was fabricated. It contained a drug-impermeable backing layer, a supporting layer preventing direct contact between the loaded drug and the backing layer, a drug-loading layer and a mucoadhesive layer. Scanning electron microscopy demonstrated the presence of the distinct layers. The composition and preparation procedure of the films influenced their mucoadhesion, swelling, in vitro release of insulin and loaded insulin stability. Vacuum drying and crosslinked PVA with glutaraldehyde might reduce mucoadhesion, and they partially decreased the bioactivity of loaded insulin. Lyophilized hydrogel film with uncrosslinked PVA as a mucoadhesive layer possessed high mucoadhesion and showed no influence on the bioactivity of loaded insulin. The application of vacuum-dried PVA-crosslinked HA-Cym/PVA hydrogel film as a drug-impermeable backing layer would provide a controllable unidirectional insulin release. Therefore, such a multilayered hydrogel film system could be a promising mucoadhesive delivery system for controlled macromolecular drug release.

[Tracking of neural stem cells in high density image sequence based on Topological constraint combined with Hungarian algorithm]

Analysis of neural stem cells' movements is one of the important parts in the fields of cellular and biological research. The main difficulty existing in cells' movement study is whether the cells tracking system can simultaneously track and analyze thousands of neural stem cells (NSCs) automatically. We present a novel cells' tracking algorithm which is based on segmentation and data association in this paper, aiming to improve the tracking accuracy further in high density NSCs' image. Firstly, we adopted different methods of segmentation base on the characteristics of the two cell image sequences in our experiment. Then we formed a data association and constituted a coefficient matrix by all cells between two adjacent frames according to topological constraints. Finally we applied The Hungarian algorithm to implement inter-cells matching optimally. Cells' tracking can be achieved according to this model from the second frame to the last one in a sequence. Experimental results showed that this approaching method has higher accuracy compared with that using the topological constraints tracking alone. The final tracking accuracies of average of sequence I and sequence II have been improved 10.17% and 4%, respectively.

Predicting the solid state phase diagram for glass-forming alloys of copper and zirconium

The free energies of six crystal structures associated with Cu-Zr alloys-Cu (face centred cubic), Cu(2)Zr, Cu(10)Zr(7), CuZr, CuZr(2) and Zr (hexagonal close packed)-are calculated using the embedded atom potential of Mendelev et al (2009 Phil. Mag. 89 967). We find that the observed low temperature stability of the Cu(10)Zr(7) and CuZr(2) phases is not reproduced. Instead, the model predicts that the CuZr phase remains stable down to T = 0 K. This discrepancy is largely removed when the interaction potentials are cut off at a short distance, such as that used by Duan et al (2005 Phys. Rev. B 71 224208). We present evidence, however, that the cut-off distance necessary to achieve the change in phase stability results in pathological artefacts in the energetics of some crystal phases.

Ghrelin contributes to derangements of glucose metabolism induced by rapamycin in mice

AIMS/HYPOTHESIS

Rapamycin impairs glucose tolerance and insulin sensitivity. Our previous study demonstrated that rapamycin significantly increases the production of gastric ghrelin, which is critical in the regulation of glucose metabolism. Here, we investigated whether ghrelin contributes to derangements of glucose metabolism induced by rapamycin.

METHODS

The effects of rapamycin on glucose metabolism were examined in mice receiving ghrelin receptor antagonist or with Ghsr1a gene knockout. Changes in GLUT4, c-Jun N-terminal kinase (JNK) and phosphorylated ribosomal protein S6 (pS6) were investigated by immunofluorescent staining or western blotting. Related hormones were detected by radioimmunoassay kits.

RESULTS

Rapamycin impaired glucose metabolism and insulin sensitivity not only in normal C57BL/6J mice but also in both obese mice induced by a high fat diet and db/db mice. This was accompanied by elevation of plasma acylated ghrelin. Rapamycin significantly increased the levels of plasma acylated ghrelin in normal C57BL/6J mice, high-fat-diet-induced obese mice and db/db mice. Elevation in plasma acylated ghrelin and derangements of glucose metabolism upon administration of rapamycin were significantly correlated. The deterioration in glucose homeostasis induced by rapamycin was blocked by D: -Lys3-GHRP-6, a ghrelin receptor antagonist, or by deletion of the Ghsr1a gene. Ghrelin receptor antagonism and Ghsr1a knockout blocked the upregulation of JNK activity and downregulation of GLUT4 levels and translocation in the gastrocnemius muscle induced by rapamycin.

CONCLUSIONS/INTERPRETATION

The current study demonstrates that ghrelin contributes to derangements of glucose metabolism induced by rapamycin via altering the content and translocation of GLUT4 in muscles.

Perceived parenting and risk for major depression in Chinese women

BACKGROUND

In Western countries, a history of major depression (MD) is associated with reports of received parenting that is low in warmth and caring and high in control and authoritarianism. Does a similar pattern exist in women in China?

METHOD

Received parenting was assessed by a shortened version of the Parental Bonding Instrument (PBI) in two groups of Han Chinese women: 1970 clinically ascertained cases with recurrent MD and 2597 matched controls. MD was assessed at personal interview.

RESULTS

Factor analysis of the PBI revealed three factors for both mothers and fathers: warmth, protectiveness, and authoritarianism. Lower warmth and protectiveness and higher authoritarianism from both mother and father were significantly associated with risk for recurrent MD. Parental warmth was positively correlated with parental protectiveness and negatively correlated with parental authoritarianism. When examined together, paternal warmth was more strongly associated with lowered risk for MD than maternal warmth. Furthermore, paternal protectiveness was negatively and maternal protectiveness positively associated with risk for MD.

CONCLUSIONS

Although the structure of received parenting is very similar in China and Western countries, the association with MD is not. High parental protectiveness is generally pathogenic in Western countries but protective in China, especially when received from the father. Our results suggest that cultural factors impact on patterns of parenting and their association with MD.

Glucose-induced beta cell dysfunction in vivo in rats: link between oxidative stress and endoplasmic reticulum stress

AIMS/HYPOTHESIS

Endoplasmic reticulum (ER) stress has been implicated in glucose-induced beta cell dysfunction. However, its causal role has not been established in vivo. Our objective was to determine the causal role of ER stress and its link to oxidative stress in glucose-induced beta cell dysfunction in vivo.

METHODS

Healthy Wistar rats were infused i.v. with glucose for 48 h to achieve 20 mmol/l hyperglycaemia with or without the co-infusion of the superoxide dismutase mimetic tempol (TPO), or the chemical chaperones 4-phenylbutyrate (PBA) or tauroursodeoxycholic acid (TUDCA). This was followed by assessment of beta cell function and measurement of ER stress markers and superoxide in islets.

RESULTS

Glucose infusion for 48 h increased mitochondrial superoxide and ER stress markers and impaired beta cell function. Co-infusion of TPO, which we previously found to reduce mitochondrial superoxide and prevent glucose-induced beta cell dysfunction, reduced ER stress markers. Similar to findings with TPO, co-infusion of PBA, which decreases mitochondrial superoxide, prevented glucose-induced beta cell dysfunction in isolated islets. TUDCA was also effective. Also similar to findings with TPO, PBA prevented beta cell dysfunction during hyperglycaemic clamps in vivo and after hyperglycaemia (15 mmol/l) for 96 h.

CONCLUSIONS/INTERPRETATION

Here, we causally implicate ER stress in hyperglycaemia-induced beta cell dysfunction in vivo. We show that: (1) there is a positive feedback cycle between oxidative stress and ER stress in glucose-induced beta cell dysfunction, which involves mitochondrial superoxide; and (2) this cycle can be interrupted by superoxide dismutase mimetics as well as chemical chaperones, which are of potential interest to preserve beta cell function in type 2 diabetes.

PLTP regulates STAT3 and NFκB in differentiated THP1 cells and human monocyte-derived macrophages

Phospholipid transfer protein (PLTP) plays an important role in regulation of inflammation. Previously published studies have shown that PLTP binds, transfers and neutralizes bacterial lipopolysaccharides. In the current study we tested the hypothesis that PLTP can also regulate anti-inflammatory pathways in macrophages. Incubation of macrophage-like differentiated THP1 cells and human monocyte-derived macrophages with wild-type PLTP in the presence or absence of tumor necrosis factor alpha (TNFα) or interferon gamma (IFNγ) significantly increased nuclear levels of active signal transducer and activator of transcription 3, pSTAT3(Tyr705) (p<0.01). Similar results were obtained in the presence of a PLTP mutant without lipid transfer activity (PLTP(M159E)), suggesting that PLTP-mediated lipid transfer is not required for activation of the STAT3 pathway. Inhibition of ABCA1 by chemical inhibitor, glyburide, as well as ABCA1 RNA inhibition, reversed the observed PLTP-mediated activation of STAT3. In addition, PLTP reduced nuclear levels of active nuclear factor kappa-B (NFκB) p65 and secretion of pro-inflammatory cytokines in conditioned media of differentiated THP1 cells and human monocyte-derived macrophages. Our data suggest that PLTP has anti-inflammatory capabilities in macrophages.