[Inhibition of Sirolimus on the growth of pancreatic carcinoma and its effect on the expression of glucose transporter and hexokinase Ⅱ]

OBJECTIVE

To investigate whether Sirolimus could affect the glycolytic catabolism pathways of pancreatic carcinoma through the control of hypoxia induced factor (HIF-1α) to inhibit the growth of tumor, and explore the potential mechanism of targeting the signaling pathways of mTOR for the treatment of pancreatic carcinoma.

METHODS

Sirolimus was applied to treat the pancreatic carcinoma in nude mice orthotopic transplantation model, its difference with the control group was compared; RT-PCR and Western blot were used to measure the mRNA and protein expression of mTOR, HIF-1α, Glucose carrier protein 1 (GLUT-1) and Hexokinase Ⅱ (HK-Ⅱ), respectively; the changes of activity of HK-Ⅱ in the tumor was determined.

RESULTS

The tumor mass of the control group (1.97±0.21)g was significantly larger than that of the Sirolimus group (0.38±0.10)g (P<0.01), and the volume of the control group (1.40±0.15) mm(3) was significantly larger than that of the Sirolimus group (0.27±0.07) mm(3) (P<0.01). The expressions of mTOR, GLUT-1 and HK-Ⅱ mRNA in the control group were higher than those of the Sirolimus group (P<0.05), while no significant change was observed in the expression of HIF-1α (P>0.05); the expressions of p-mTOR, HIF-1α, GLUT-1 and HK-Ⅱ proteins in the control group were higher than those of the Sirolimus group (P<0.05). The activity of HK-Ⅱ in the control group was higher than that of the Sirolimus group (P<0.05).

CONCLUSION

Sirolimus could affect the expression of GLUT-1 and HK-Ⅱ in pancreatic carcinoma through the effects of HIF-1α to inhibit tumor growth, indicating that blocking the mTOR pathway could control the glycolytic metabolism pathways of pancreatic carcinoma, which may become the new strategy for the treatment of pancreatic carcinoma.

Influence of Parent Artery Segmentation and Boundary Conditions on Hemodynamic Characteristics of Intracranial Aneurysms

PURPOSE

The purpose of this study is to explore the influence of segmentation of the upstream and downstream parent artery and hemodynamic boundary conditions (BCs) on the evaluated hemodynamic factors for the computational fluid dynamics (CFD) analysis of intracranial aneurysms.

MATERIALS AND METHODS

Three dimensional patient-specific aneurysm models were analyzed by applying various combinations of inlet and outlet BCs. Hemodynamic factors such as velocity pattern, streamline, wall shear stress, and oscillatory shear index at the systolic time were visualized and compared among the different cases.

RESULTS

Hemodynamic factors were significantly affected by the inlet BCs while there was little influence of the outlet BCs. When the inlet length was relatively short, different inlet BCs showed different hemodynamic factors and the calculated hemodynamic factors were also dependent on the inlet length. However, when the inlet length (L) was long enough (L>20D, where D is the diameter of inlet section), the hemodynamic factors became similar regardless of the inlet BCs and lengths. The error due to different inlet BCs was negligible. The effect of the outlet length on the hemodynamic factors was similar to that of the inlet length.

CONCLUSION

Simulated hemodynamic factors are highly sensitive to inlet BCs and upstream parent artery segmentation. The results of this work can provide an insight into how to build models and to apply BCs for more accurate estimation of hemodynamic factors from CFD simulations of intracranial aneurysms.

Neurodevelopmental delay with critical congenital heart disease is mainly from prenatal injury not infant cardiac surgery: current evidence based on a meta-analysis of functional magnetic resonance imaging

OBJECTIVE

No consensus has been reached regarding whether brain injury related to congenital heart disease (CHD) is caused by infant cardiac surgery and/or prenatal injury resulting from the CHD. We performed this meta-analysis to identify the likely cause of neurodevelopmental delay in CHD patients.

METHODS

We carried out a literature search without language restriction in December 2013, retrieving records from PubMed, EMBASE, the Cochrane Library and the World Health Organization trials center, to identify studies applying functional magnetic resonance imaging (fMRI) evaluation of brain function before surgery and, in some cases, after surgery (both immediate term and short term postoperatively). The preoperative and postoperative fMRI results were extracted, and meta-analysis was performed using Revman 5.1.1 and STATA 11.0, according to the guidelines from the Cochrane review and MOOSE groups.

RESULTS

The electronic search yielded 937 citations. Full text was retrieved for 15 articles and eight articles (nine studies) were eligible for inclusion: six studies (n = 312 cases) with fMRI analysis before surgery and three (n = 36 cases) with complete perioperative fMRI analysis. The overall average diffusivity of CHD cases was significantly higher than that of controls, with a summarized standard (std) mean difference of 1.39 (95% CI, 0.70-2.08), and the fractional anisotropy was lower in CHD cases, with a summarized mean difference of -1.43 (95% CI, -1.95 to -0.91). N-acetylaspartate (NAA)/choline (Cho) for the whole brain was significantly lower in CHD cases compared with healthy ones, while lactate/Cho was significantly higher in CHD cases. Immediate term postoperatively, significant changes in NAA/creatine and NAA/Cho, relative to preoperative values, were found. However, the difference did not persist at the short-term follow-up.

CONCLUSION

This meta-analysis suggests that the delay in neurological development in newborns with CHD is due mainly to prenatal injury, and cardiac surgery might lead to mild brain injuries postoperatively, but fMRI shows recovery within a short period.

Development of the scintillator-based probe for fast-ion losses in the HL-2A tokamak

A new scintillator-based lost fast-ion probe (SLIP) has been developed and operated in the HL-2A tokamak [L. W. Yan, X. R. Duan, X. T. Ding, J. Q. Dong, Q. W. Yang, Yi Liu, X. L. Zou, D. Q. Liu, W. M. Xuan, L. Y. Chen, J. Rao, X. M. Song, Y. Huang, W. C. Mao, Q. M. Wang, Q. Li, Z. Cao, B. Li, J. Y. Cao, G. J. Lei, J. H. Zhang, X. D. Li, W. Chen, J. Chen, C. H. Cui, Z. Y. Cui, Z. C. Deng, Y. B. Dong, B. B. Feng, Q. D. Gao, X. Y. Han, W. Y. Hong, M. Huang, X. Q. Ji, Z. H. Kang, D. F. Kong, T. Lan, G. S. Li, H. J. Li, Qing Li, W. Li, Y. G. Li, A. D. Liu, Z. T. Liu, C. W. Luo, X. H. Mao, Y. D. Pan, J. F. Peng, Z. B. Shi, S. D. Song, X. Y. Song, H. J. Sun, A. K. Wang, M. X. Wang, Y. Q. Wang, W. W. Xiao, Y. F. Xie, L. H. Yao, D. L. Yu, B. S. Yuan, K. J. Zhao, G. W. Zhong, J. Zhou, J. C. Yan, C. X. Yu, C. H. Pan, Y. Liu, and the HL-2A Team, Nucl. Fusion 51, 094016 (2011)] to measure the losses of neutral beam ions. The design of the probe is based on the concept of the α-particle detectors on Tokamak Fusion Test Reactor (TFTR) using scintillator plates. The probe is capable of traveling across an equatorial plane port and sweeping the aperture angle rotationally with respect to the axis of the probe shaft by two step motors, in order to optimize the radial position and the collimator angle. The energy and the pitch angle of the lost fast ions can be simultaneously measured if the two-dimensional image of scintillation light intensity due to the impact of the lost fast ions is detected. Measurements of the fast-ion losses using the probe have been performed during HL-2A neutral beam injection discharges. The clear experimental evidence of enhanced losses of beam ions during disruptions has been obtained by means of the SLIP system. A detailed description of the probe system and the first experimental results are reported.

Molecular cloning and characterization of a novel chicken gene named grni

The full-length cDNA sequence of a novel expressed sequence tag (GenBank accession No. HQ184338) that was differentially expressed during Newcastle disease virus (NDV) infection in chickens was cloned from the chicken spleen by a rapid amplification of cDNA ends assay. This gene was further analyzed using bioinformatic methods and named grni. The full-length cDNA sequence was 1698 bp without introns, locating between 104,691,934 and 104,693,618 in galGal4 on chromosome 2. The open reading frame (ORF) contained 261 bp and encoded a deduced protein of 86 amino acid residues. Furthermore, the encoded protein contained two transmembrane regions without signal peptides, indicating that this protein is located in the mitochondrial membrane. Moreover, its homologous protein was not identified. Real-time polymerase chain reaction was used to detect the dynamic mRNA expression of this gene in the spleen, thymus, bursa of Fabricius, and trachea of NDV-infected chickens. Results suggested that the gene was involved in the transcriptional response of chicken to NDV infection. To obtain a fusion protein and prepare rabbit anti-serum, the predicted ORF of this gene was expressed in Escherichia coli. The expression of this gene at the protein level was further confirmed in the spleen, thymus, and bursa of Fabricius of NDV-infected chickens using Western blot analysis. In conclusion, a novel protein-coding gene named grni was successfully cloned and identified in chickens. Furthermore, this gene was found to be involved in the response of chickens to NDV infection.

Identification and characterization of the geranylgeranyl diphosphate synthase in Deinococcus radiodurans

Deinococcus radiodurans strain R1 utilizes multiple antioxidants including a unique carotenoid, deinoxanthin, to fight again oxidative stress. Most of the enzymes involved in the deinoxanthin biosynthetic pathway have been identified. However, the enzyme catalysing the synthesis of geranylgeranyl diphosphate (GGPP), which is a precursor of carotenoid biosynthesis, has yet to be identified. Two putative isoprenyl diphosphate synthases (IPPS) homologues (DR1395 and DR932) were screened out by analysis of conserved amino acid regions, and their biochemical functions were investigated. Gene mutation, gene expression in Escherichia coli and analysis of carotenoid products were used to investigate the functions of these candidates. The results suggested that DR1395 encodes the protein for GGPP synthesis. Site-directed mutant analysis indicated that the amino acid composition of and around the first aspartate-rich motif is vital for GGPP synthase function.

SIGNIFICANCE AND IMPACT OF THE STUDY

Deinococcus radiodurans strain R1 produces a unique carotenoid product, deinoxanthin, as an antioxidant. In this study, DR1395 was identified as the gene encoding geranylgeranyl diphosphate synthase (GGPPS) for entrance to deinoxanthin biosynthesis in D. radiodurans. Moreover, site-directed mutagenesis studies on DR1395 identified the effect of amino acid composition of the aspartate-rich motif on the production of this carotenoid. This study demonstrated the entrance step in the deinoxanthin biosynthetic pathway. These results can be useful in genetic engineering strategies for deinoxanthin production including enhancement of GGPPS gene expression in D. radiodurans.

Endoplasmic reticulum stress upregulates protein tyrosine phosphatase 1B and impairs glucose uptake in cultured myotubes

AIMS/HYPOTHESIS

Endoplasmic reticulum (ER) stress has been recognised as a common pathway in the development of obesity-associated insulin resistance. Protein tyrosine phosphatase 1B (PTP1B) is a negative regulator of insulin signalling and is localised on the ER membrane. The aim of the study was to investigate the cross-talk between ER stress and PTP1B.

METHODS

Leptin-deficient obese (ob/ob), Ptp1b (also known as Ptpn1) knockout and C57BL/6J mice were subjected to a high-fat or normal-chow diet for 20 weeks. ER stress was induced in cultured myotubes by treatment with tunicamycin. Immunohistochemistry and western blotting were used to assess proteins involved in the ER stress response. Myotube glucose uptake was determined by measuring 2-deoxy[(3)H]glucose incorporation.

RESULTS

A high-fat diet induced ER stress and PTP1B expression in the muscle tissue of mice and these responses were attenuated by treatment with the ER chaperone tauroursodeoxycholic acid (TUDCA). Cultured myotubes exhibited increased levels of PTP1B in response to tunicamycin treatment. Silencing of Ptp1b with small interfering RNA (siRNA) or overexpression of Ptp1b with adenovirus construct failed to alter the levels of ER stress. Ptp1b knockout mice did not differ from the wild-type mice in the extent of tunicamycin-induced upregulation of glucose-regulated protein-78. However, tunicamycin-induced phosphorylation of eukaryotic initiation factor 2α and c-Jun NH(2)-terminal kinase-2 were significantly attenuated in the Ptp1b knockout mice. Treatment with TUDCA or silencing of PTP1B reversed tunicamycin-induced blunted myotube glucose uptake.

CONCLUSIONS/INTERPRETATION

Our data suggest that PTP1B is activated by ER stress and is required for full-range activation of ER stress pathways in mediating insulin resistance in the skeletal muscle.

Intervention of TLR4 signal pathway cytokines in severe liver injury with obstructive jaundice in rats

Obstructive jaundice is a common surgical disease and a variety of end-stage severe liver injuries still lack effective treatments. Compared to traditional liver transplantation therapy, herbal treatment is noninvasive and has fewer side effects. Research results have shown that a modified major decoction of bupleurum can reduce the toxic reaction of obstructive jaundice, even though the mechanism is unclear. A period of chronic exercise training can significantly reduce TLR4 expression in mononuclear cells and the secretion of inflammatory cell factors. Our study administered a modified major decoction of bupleurum in combination with exercise in rats with obstructive jaundice and the results indicated that applying a major bupleurum decoction in combination with moderately intense aerobic exercise showed a beneficial effect on adjusting the expression of liver inflammatory cytokines, which thus improved immunity and finally reduced the liver injury of rats with obstructive jaundice.

Clot formation, vascular repair and hematoma resolution after ICH, a coordinating role for thrombin?

Following intracerebral hemorrhage (ICH) there is a sequential response involving activation of the coagulation cascade/platelet plug formation, vascular repair, upregulation of endogenous defense mechanisms and clot resolution. How these responses are coordinated and modified by different hematoma sizes has received little attention. This paper reviews evidence that thrombin can modulate and may coordinate the components of the endogenous response. This has potential consequences for treatment of ICH with a number of modalities.

Minocycline attenuates brain edema, brain atrophy and neurological deficits after intracerebral hemorrhage

Evidence suggests that microglia activation contributes to brain injury after intracerebral hemorrhage (ICH). The present study aimed to determine if minocycline, an inhibitor of microglia activation, can reduce brain edema, brain atrophy and neurological deficits after ICH.Male Sprague-Dawley rats received an infusion of 100-microL autologous whole blood into the right basal ganglia. Rats received minocycline or vehicle treatment. There were two sets of experiments in this study. In the first set of experiments, the effects of minocycline on ICH-induced brain edema were examined at day 3. In the second set, behavioral tests were performed at days 1, 3, 7, 14 and 28. Rats were killed at day 28 for brain atrophy measurement (caudate and lateral ventricle size).Minocycline reduced perihematomal brain edema in the ipsilateral basal ganglia (78.8 +/- 0.4 vs. 80.9 +/- 1.1% in the vehicle-treated group, p < 0.01). Minocycline also improved functional outcome. In addition, minocycline reduced brain tissue loss in the ipsilateral caudate (p < 0.01) and ventricular enlargement (p < 0.05).In conclusion, minocycline attenuates ICH-induced brain edema formation, neurological deficits and brain atrophy in rats suggesting an important role of microglia in ICH-related brain injury.

Effects of carotenoids from Deinococcus radiodurans on protein oxidation

AIMS

To evaluate the antioxidant effect of carotenoids from Deinococcus radiodurans on protein.

METHODS AND RESULTS

Deinococcus radiodurans strain R1 (ATCC 13939) and its mutant strain R1DeltacrtB were used for this study. The total carotenoids (R1ex) from D. radiodurans were obtained by extraction with acetone/methanol (7 : 2, by vol), and their antioxidant activity was measured using the DPPH (2,2-diphenyl-1-picrylhydrazyl) system. The protein oxidation level, in vitro and in the cell, was measured using the DNPH (2,4-dinitrophenyl hydrazine) method. The carotenoid extract R1ex scavenged 40.2% DPPH radicals compared to beta-carotene (31.7%) at a concentration of 0.5 mg ml(-1). The intracellular level of protein oxidation in mutant R1DeltacrtB, which does not contain carotenoid, was 0.0212 mmol mg(-1) protein which is significantly greater than that in the wild type (0.0169 mmol mg(-1) protein) following the treatment with H(2)O(2). The purified major carotenoid product (deinoxanthin) from the wild type showed a greater inhibition of oxidative damage in bovine serum albumin than lycopene or lutein.

CONCLUSIONS

Carotenoids prevent protein oxidation and contribute to the resistance to cell damage in D. radiodurans.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results provide the evidence that carotenoids can protect proteins in D. radiodurans against oxidative stress.

Blood-brain barrier function in intracerebral hemorrhage

In this paper, we review current knowledge on blood-brain barrier (BBB) dysfunction following intracerebral hemorrhage (ICH). BBB disruption is a hallmark of ICH-induced brain injury. Such disruption contributes to edema formation, the influx of leukocytes, and the entry of potentially neuroactive agents into the perihematomal brain, all of which may contribute to brain injury. A range of factors have been implicated in inducing BBB disruption, including inflammatory mediators (e.g., cytokines and chemokines), thrombin, hemoglobin breakdown products, oxidative stress, complement, and matrix metalloproteinases. While there is interaction between some of these mediators, it is probable that prevention of ICH-induced BBB disruption will involve blocking multiple pathways or blocking a common end pathway (e.g., by stabilizing tight junction structure). While the effects of ICH on BBB passive permeability have been extensively examined, effects on other 'barrier' properties (metabolic and transport functions) have been less well-studied. However, recent data suggests that ICH can affect transport and that this may help protect the BBB and the brain. Indeed, it is possible in small bleeds that BBB disruption may be beneficial, and it is only in the presence of larger bleeds that disruption has detrimental effects.

Microglial activation and brain injury after intracerebral hemorrhage

Microglial activation and thrombin formation contribute to brain injury after intracerebral hemorrhage (ICH). Tumor necrosis factor-alpha (TNF-alpha) and interleukin-1 beta (IL-1beta) are 2 major proinflammatory cytokines. In this study, we investigated whether thrombin stimulates TNF-alpha and IL-1beta secretion in vitro, and whether microglial inhibition reduces ICH-induced brain injury in vivo. There were 2 parts to this study. In the first part, cultured rat microglial cells were treated with vehicle, thrombin (5 and 10U/mL), or thrombin plus tuftsin (0.05 microg/mL), an inhibitor of microglia activation. Levels of TNF-alpha and IL-1beta in culture medium were measured by ELISA at 4, 8, and 24 h after thrombin treatment. In the second part of the study, rats received an intracerebral infusion of 100 microL autologous whole blood with or without 25 microg of tuftsin 1-3 fragment. Rats were killed at day 1 or day 3 for immunohistochemistry and brain water content measurement. We found that thrombin receptors were expressed in cultured microglia cells, and TNF-alpha and IL-1beta levels in the culture medium were increased after thrombin treatment. Tuftsin reduced thrombin-induced upregulation of TNF-alpha and IL-1beta. In vivo, microglia were activated after ICH, and intracerebral injection of tuftsin reduced brain edema in the ipsilateral basal ganglia (81.1 +/- 0.7% vs. 82.7 +/- 1.3% in vehicle-treated group; p < 0.05) after ICH. These results suggest a critical role of microglia activation in ICH-related brain injury.

Hyperbaric oxygen for experimental intracerebral hemorrhage

Acute brain edema formation contributes to brain injury after intracerebral hemorrhage (ICH). It has been reported that hyperbaric oxygen (HBO) is neuroprotective in cerebral ischemia, subarachnoid hemorrhage, and brain trauma. In this study, we investigated the effects of HBO on brain edema following ICH in rats. Male Sprague-Dawley rats received intracerebral infusion of autologous whole blood, thrombin, or ferrous iron. HBO (100% O2, 3.0 ATA for 1 h) was initiated 1 h after intracerebral injection. Control rats were exposed to air at room pressure. Brains were sampled at 24 or 72 h for water content, ion measurement, and Western blot analysis. We found that 1 session of HBO reduced perihematomal brain edema (p < 0.05) 24 h after ICH. HBO also reduced heat shock protein-32 (HSP-32) levels (p < 0.05) in ipsilateral basal ganglia 24h after ICH. However, HBO failed to attenuate thrombin-induced brain edema and exaggerated ferrous iron-induced brain edema (p < 0.05). Three sessions of HBO also failed to reduce brain edema 72h after ICH. In summary, HBO reduced early perihematomal brain edema and HSP-32 levels in brain. HBO-related brain protection does not occur through reduction in thrombin toxicity because HBO failed to attenuate thrombin-induced brain edema. Our results also indicate that HBO treatment after hematoma lysis for ICH may be harmful, since HBO amplifies iron-induced brain edema.