IL-25 or IL-17E Protects against High-Fat Diet-Induced Hepatic Steatosis in Mice Dependent upon IL-13 Activation of STAT6.

IL-25 or IL-17E is a member of IL-17 cytokine family and has immune-modulating activities. The role of IL-25 in maintaining lipid metabolic homeostasis remains unknown. We investigated the effects of exogenous IL-25 or deficiency of IL-25 on hepatic lipid accumulation. IL-25 expression was examined in paraffin-embedded tissue sections of liver from patients or in the livers from mice. Mouse model of steatosis was induced by feeding a high-fat diet (HFD). Extent of steatosis as well as expression of cytokines, key enzymes for lipid metabolic pathways, markers for Kupffer cells/macrophages, and lipid droplet (LD) proteins, were analyzed. Our results show that hepatic steatosis in mice was accompanied by increased LD proteins, but decreased IL-25 in the liver. Decreased hepatic IL-25 was also observed in patients with fatty liver. Administration of IL-25 to HFD-fed wild-type mice led to a significant improvement in hepatic steatosis. This effect was associated with increased expression of IL-13, development of alternatively activated Kupffer cells/macrophages, and decreased expression of LD proteins in the liver. In contrast, administration of IL-25 to HFD-fed mice deficient in STAT6 or IL-13 had no effects. In addition, stimulation of primary hepatocytes with IL-13, but not IL-25, resulted in downregulation of LD proteins. Finally, mice deficient in IL-25 had exacerbated hepatic lipid accumulation when fed the HFD. These data demonstrate that dysregulated IL-25 expression contributes to lipid accumulation, whereas exogenous IL-25 protects against hepatic steatosis through IL-13 activation of STAT6. IL-25 and IL-13 are potential therapeutic agents for hepatic steatosis and associated pathologies.

Ischemia-induced endothelial cell swelling and mitochondrial dysfunction are attenuated by cinnamtannin D1, green tea extract, and resveratrol in vitro.

Polyphenols possess antioxidant and anti-inflammatory properties. Oxidative stress (OS) and inflammation have been implicated in the pathogenesis of cytotoxic brain edema in cerebral ischemia. In addition, OS and pro-inflammatory cytokines also damage the endothelial cells and the neurovascular unit. Endothelial cell swelling may contribute to a leaky blood-brain barrier which may result in vasogenic edema in the continued presence of the existing cytotoxic edema. We investigated the protective effects of polyphenols on cytotoxic cell swelling in bEND3 endothelial cultures subjected to 5 hours oxygen-glucose deprivation (OGD). A polyphenol trimer from cinnamon (cinnamtannin D1), a polyphenol-rich extract from green tea, and resveratrol prevented the OGD-induced rise in mitochondrial free radicals, cell swelling, and the dissipation of the inner mitochondrial membrane potential. Monocyte chemoattractant protein (also called CCL2), a chemokine, but not tumor necrosis factor-α or interleukin-6, augmented the cell swelling. This effect of monochemoattractant protein 1-1 was attenuated by the polyphenols. Cyclosporin A, a blocker of the mitochondrial permeability transition pore, did not attenuate cell swelling but BAPTA-AM, an intracellular calcium chelator did, indicating a role of [Ca(2+)]i but not the mPT in cell swelling. These results indicate that the polyphenols reduce mitochondrial reactive oxygen species and subsequent cell swelling in endothelial cells following ischemic injury and thus may reduce brain edema and associated neural damage in ischemia. One possible mechanism by which the polyphenols may attenuate endothelial cell swelling is through the reduction in [Ca(2+)]i.

Exercise intervention in middle-aged and elderly individuals with insomnia improves sleep and restores connectivity in the motor network.

Exercise is a potential treatment to improve sleep quality in middle-aged and elderly individuals. Understanding exercise-induced changes in functional plasticity of brain circuits that underlie improvements in sleep among middle-aged and older adults can inform treatment of sleep problems. The aim of the study is to identify the effects of a 12-week exercise program on sleep quality and brain functional connectivity in middle-aged and older adults with insomnia. The trial was registered with Chinese Clinical Trial Register (ChiCTR2000033652). We recruited 84 healthy sleepers and 85 individuals with insomnia. Participants with insomnia were assigned to receive either a 12-week exercise intervention or were placed in a 12-week waitlist control condition. Thirty-seven middle-aged and older adults in the exercise group and 30 in the waitlist group completed both baseline and week 12 assessments. We found that middle-aged and older adults with insomnia showed significantly worse sleep quality than healthy sleepers. At the brain circuit level, insomnia patients showed decreased connectivity in the widespread motor network. After exercise intervention, self-reported sleep was increased in the exercise group (P < 0.001) compared to that in the waitlist group. We also found increased functional connectivity of the motor network with the cerebellum in the exercise group (P < 0.001). Moreover, we observed significant correlations between improvement in subjective sleep indices and connectivity changes within the motor network. We highlight exercise-induced improvement in sleep quality and functional plasticity of the aging brain.

Parasitic nematode-induced modulation of body weight and associated metabolic dysfunction in mouse models of obesity.

Obesity is associated with a chronic low-grade inflammation characterized by increased levels of proinflammatory cytokines that are implicated in disrupted metabolic homeostasis. Parasitic nematode infection induces a polarized Th2 cytokine response and has been explored to treat autoimmune diseases. We investigated the effects of nematode infection against obesity and the associated metabolic dysfunction. Infection of RIP2-Opa1KO mice or C57BL/6 mice fed a high-fat diet (HFD) with Nippostrongylus brasiliensis decreased weight gain and was associated with improved glucose metabolism. Infection of obese mice fed the HFD reduced body weight and adipose tissue mass, ameliorated hepatic steatosis associated with a decreased expression of key lipogenic enzymes/mediators, and improved glucose metabolism, accompanied by changes in the profile of metabolic hormones. The infection resulted in a phenotypic change in adipose tissue macrophages that was characterized by upregulation of alternative activation markers. Interleukin-13 (IL-13) activation of the STAT6 signaling pathway was required for the infection-induced attenuation of steatosis but not for improved glucose metabolism, whereas weight loss was attributed to both IL-13/STAT6-dependent and -independent mechanisms. Parasitic nematode infection has both preventive and therapeutic effects against the development of obesity and associated features of metabolic dysfunction in mice.

Design of a Low-Frequency Dielectrophoresis-Based Arc Microfluidic Chip for Multigroup Cell Sorting.

Dielectrophoresis technology is applied to microfluidic chips to achieve microscopic control of cells. Currently, microfluidic chips based on dielectrophoresis have certain limitations in terms of cell sorting species, in order to explore a microfluidic chip with excellent performance and high versatility. In this paper, we designed a microfluidic chip that can be used for continuous cell sorting, with the structural design of a curved channel and curved double side electrodes. CM factors were calculated for eight human healthy blood cells and cancerous cells using the software MyDEP, the simulation of various blood cells sorting and the simulation of the joule heat effect of the microfluidic chip were completed using the software COMSOL Multiphysics. The effect of voltage and inlet flow velocity on the simulation results was discussed using the control variables method. We found feasible parameters from simulation results under different voltages and inlet flow velocities, and the feasibility of the design was verified from multiple perspectives by measuring cell movement trajectories, cell recovery rate and separation purity. This paper provides a universal method for cell, particle and even protein sorting.

Application and realization of Norland optical adhesive 73 novel photosensitive macromolecular material for the rapid preparation of periodically tunable nanoscale gratings.

Periodically tunable nano-gratings have an irreplaceable role in spectral scanning and optical communication, but the performance of gratings manufactured from different materials varies considerably, and the development of superior materials has energized the preparation of high-precision devices. This paper presents a nanoscale preparation process based on Norland Optical Adhesive 73 (NOA73), which enables the rapid preparation of periodically tunable nano-gratings with up to 100% light transmission. The powerful fluidity and shear rate of NOA73 make it uniquely suited to the preparation of precision devices, allowing the production of up to dense grating structures and offering the possibility of making nanoscale gratings. This paper uses multi-angle hierarchical lithography, die stretching, and replication to achieve further improvements in accuracy and successfully prepare gratings with a period of 500 nm. The successful preparation of NOA73 nano-gratings demonstrates the practicality of NOA73 as a material for precision device fabrication.

An extract of chokeberry attenuates weight gain and modulates insulin, adipogenic and inflammatory signalling pathways in epididymal adipose tissue of rats fed a fructose-rich diet.

Chokeberries are a rich source of anthocyanins, which may contribute to the prevention of obesity and the metabolic syndrome. The aim of the present study was to determine if an extract from chokeberries would reduce weight gain in rats fed a fructose-rich diet (FRD) and to explore the potential mechanisms related to insulin signalling, adipogenesis and inflammatory-related pathways. Wistar rats were fed a FRD for 6 weeks to induce insulin resistance, with or without chokeberry extract (CBE) added to the drinking-water (100 and 200 mg/kg body weight, daily: CBE100 and CBE200). Both doses of CBE consumption lowered epididymal fat, blood glucose, TAG, cholesterol and LDL-cholesterol. CBE consumption also elevated plasma adiponectin levels and inhibited plasma TNF-α and IL6, compared with the control group. There were increases in the mRNA expression for Irs1, Irs2, Pi3k, Glut1, Glut4 and Gys1, and decreases in mRNA levels of Gsk3ß. The protein and gene expression of adiponectin and Pparγ mRNA levels were up-regulated and Fabp4, Fas and Lpl mRNA levels were inhibited. The levels of gene expression of inflammatory cytokines, such as Il1ß, Il6 and Tnfα were lowered, and protein and gene expression of ZFP36 (zinc finger protein) were enhanced in the epididymal adipose tissue of the rats that consumed the CBE200 extract. In summary, these results suggest that the CBE decreased risk factors related to insulin resistance by modulating multiple pathways associated with insulin signalling, adipogenesis and inflammation.

IL-25 Treatment Improves Metabolic Syndrome in High-Fat Diet and Genetic Models of Obesity.

INTRODUCTION: Endemic obesity is considered the driving force for the dramatic increase in incidence of type 2 diabetes (T2D). There is mounting evidence that chronic, low-grade inflammation driven by Th1/Th17 cells and M1 macrophages, is a critical link between obesity and insulin resistance. IL-25 promotes development of a Th2 immune response and M2 macrophages that counteract the inflammation associated with obesity and T2D. METHODS: Mice were fed a high-fat diet (HFD) for 16 weeks and then treated with IL-25 or BSA as a control for 21 days. Body weight, blood glucose levels, intraperitoneal glucose tolerance, and gene expression were evaluated in mice treated with BSA or IL-25. Ob/ob mice fed a normal control diet were also treated with BSA or IL-25 and body weight and blood glucose levels were measured. Transepithelial electrical resistance and sodium-linked glucose absorption were determined in muscle-free small intestinal tissue and glucose absorption assessed in vitro in intestinal epithelial and skeletal muscle cell lines. RESULTS: Administration of IL-25 to HFD fed mice reversed glucose intolerance, an effect mediated in part by reduction in SGLT-1 activity and Glut2 expression. Importantly, the improved glucose tolerance in HFD mice treated with IL-25 was maintained for several weeks post-treatment indicating long-term changes in glucose metabolism in obese mice. Glucose intolerance was also reversed by IL-25 treatment in genetically obese ob/ob mice without inducing weight loss. In vitro studies demonstrated that glucose absorption was inhibited by IL-25 treatment in the epithelial IPEC-1 cells but increased glucose absorption in the L6 skeletal muscle cells. This supports a direct cell-specific effect of IL-25 on glucose metabolism. CONCLUSION: These results suggest that the IL-25 pathway may be a useful target for the treatment of metabolic syndrome.

Tumor necrosis factor-alpha induces intestinal insulin resistance and stimulates the overproduction of intestinal apolipoprotein B48-containing lipoproteins.

There is growing evidence suggesting intestinal insulin resistance and overproduction of apolipoprotein (apo) B48-containing chylomicrons in insulin-resistant states. In the current study, we investigated the potential role of the inflammatory cytokine tumor necrosis factor-alpha (TNF-alpha) in the development of insulin resistance and aberrant lipoprotein metabolism in the small intestine in a Syrian golden hamster model. TNF-alpha infusion decreased whole-body insulin sensitivity, based on in vivo euglycemic clamp studies in chow-fed hamsters. Analysis of intestinal tissue in TNF-alpha-treated hamsters indicated impaired phosphorylation of insulin receptor-beta, insulin receptor substrate-1, Akt, and Shc and increased phosphorylation of p38, extracellular signal-related kinase-1/2, and Jun NH(2)-terminal kinase. TNF-alpha infusion also increased intestinal production of total apoB48, triglyceride-rich lipoprotein apoB48, and serum triglyceride levels in both fasting and postprandial (fat load) states. The effects of TNF-alpha on plasma apoB48 levels could be blocked by the p38 inhibitor SB203580. Ex vivo experiments using freshly isolated enterocytes also showed TNF-alpha-induced p38 phosphorylation and intestinal apoB48 overproduction, effects that could be blocked by SB203580. Interestingly, TNF-alpha increased the mRNA and protein mass of intestinal microsomal triglyceride transfer protein without altering apoB mRNA levels. Enterocytes were found to have detectable levels of both TNF-alpha receptor types (p55 and p75), and antibodies against either of the two TNF-alpha receptors partially blocked the stimulatory effect of TNF-alpha on apoB48 production and p38 phosphorylation. In summary, these data suggest that intestinal insulin resistance can be induced in hamsters by TNF-alpha infusion, and it is accompanied by intestinal overproduction of apoB48-containing lipoproteins. TNF-alpha-induced stimulation of intestinal lipoprotein production appears to be mediated via TNF-alpha receptors and the p38 mitogen-activated protein kinase pathway.

Stress exposure alters brain mRNA expression of the genes involved in insulin signalling, an effect modified by a high fat/high fructose diet and cinnamon supplement.

In occidental societies, high fat and high sugar diets often coincide with episodes of stress. The association is likely to modify brain energy control. Brain insulin signalling is rarely studied in stressed individuals consuming high fat diets. Furthermore the effects of cinnamon supplement are not known in these conditions. Therefore, we exposed rats, over a 12-week period, to a control (C) or a high fat/high fructose (HF/HFr) diet that induces peripheral insulin resistance. A cinnamon supplement (C+CN and HF/HFr +CN) was added or not. After diet exposure, one group of rats was exposed to a 30-min restraint followed by a 10-min open-field test, their combination featuring a moderate stressor, the other rats staying unstressed in their home cages. The insulin signalling in hippocampus and frontal cortex was studied through the mRNA expression of the following genes: insulin receptor (Ir), insulin receptor substrate (Irs1), glucose transporters (Glut1 and Glut3), glycogen synthase (Gys1) and their modulators, Akt1 and Pten. In C rats, stress enhanced the expression of Ir, Irs1, Glut1, Gys1 and Akt1 mRNA. In C+CN rats, stress induced an increase in Pten but a decrease in Gys1 mRNA expression. In HF/HFr rats, stress was associated with an increase in Pten mRNA expression. In HF/HFr+CN rats, stress increased Pten mRNA expression but also decreased Gys1 mRNA expression. This suggests that a single moderate stress favours energy refilling mechanisms, an effect blunted by a previous HF/HFr diet and cinnamon supplement.

Voluntary running improves in vivo insulin resistance in high-salt diet fed rats.

It is well known that exercise training, including voluntary running (VR), improves insulin resistance. However, the effect of VR on insulin resistance induced by high salt intake is unclear. The aim of this study was to determine whether VR would improve the glucose utilization in normal male Sprague-Dawley rats fed a high-salt diet (HSD) on 2-week early prevention and 1-week midway intervention protocols. In vivo glucose utilization was measured by euglycemic clamp technique. Further analyses of the possible changes in insulin signaling occurring in skeletal muscle were performed by Western blot and reverse transcription polymerase chain reaction (RT-PCR). The glucose infusion rates (GIRs) after 2 weeks of HSD feeding were decreased (HSD vs. control: 21.5 +/- 0.8 vs. 27 +/- 0.5 mg/kg body wt/min; P < 0.05), and improved by 2 weeks VR to 30.5 +/- 1.5 mg/kg body wt/min. Additionally, the GIRs after 3 weeks of HSD feeding were decreased (HSD vs. control: 20.0 +/- 0.3 vs. 26.5 +/- 0.6 mg/kg body wt/min; P < 0.05), and they also improved by the third week of VR (28.5 +/- 0.7 mg/ kg body wt/min vs. sedentary; P < 0.01). There were no differences in skeletal muscle for the total mass of insulin receptor-beta (IR-beta), IR substrate-1 (IRS-1), Akt, and glucose transporter 4 (GLUT4) in any of the groups of 2 weeks of HSD loading control and VR. VR did not regulate the enhanced tyrosine phosphorylation of IR-beta and IRS-1 by 2 weeks of HSD feeding. However, the enhanced serine phosphorylation of Akt and the tyrosine phosphorylation of GLUT4 were significantly inhibited by the early VR. HSD also impaired GLUT4 content in the plasma membrane and mRNA expression, but the decreases were improved by 2 weeks of VR. These results suggest that early voluntary exercise would prevent the development of insulin resistance induced by an HSD due in part by enhancing the impaired GLUT4 translocation and mRNA expression in skeletal muscle.

Increased expression of hepatic pyruvate dehydrogenase kinases 2 and 4 in young and middle-aged Otsuka Long-Evans Tokushima Fatty rats: induction by elevated levels of free fatty acids.

The activity of the pyruvate dehydrogenase complex (PDC) is regulated by covalent modification of its E1 component, which is catalyzed by specific pyruvate dehydrogenase kinases (PDKs) and phosphatases. In the liver, PDK2 and PDK4 are the most abundant PDK isoforms, which are responsible for inactivation of PDC when glucose availability is scarce in the body. In the present study, regulatory mechanisms of hepatic PDC were examined before and after the onset of type 2 diabetes mellitus in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, using Long-Evans Tokushima Otsuka (LETO) rats as controls. Plasma glucose and insulin concentrations were at normal levels in rats aged 8 weeks, but were significantly higher in OLETF than in LETO rats aged 25 weeks, indicating insulin resistance in OLETF rats. Plasma free fatty acids (FFAs) were 1.6-fold concentrated, and the liver PDC activity was significantly lower in OLETF than in LETO rats at both ages, suggesting suppression of pyruvate oxidative decarboxylation in OLETF rats before and after the onset of diabetes. Pyruvate dehydrogenase kinase activity and abundance of PDK2 and PDK4 proteins, as well as mRNAs, were greater in OLETF rats at both ages. These results suggest that persistently elevated levels of circulating free fatty acid in normal and diabetic OLETF rats play an important role in stimulating PDK2 and PDK4 expression in liver.

[Investigation of follicular development and oocyte maturation after cryopreservation and xenograft of newborn mouse ovaries].

In order to explore the feasibility of cryopreserving primordial follicles in attaining their developmental competence following freezing and thawing, ovaries from newborn mice were cryopreserved and the thawed ovaries were xenografted into kidney capsules of adult female mice. Ovaries were isolated from newborn B6C2F(1) female mice, infiltrated by Leibovitz 15 (L-15) medium containing 10% (V/V) fetal bovine serum (FBS) and 1.5 mol/L dimethylsulfoxide (DMSO), and then packed into 0.25 ml plastic straws. The ovaries contained in straws were frozen under nitrogen vapour at -40 degrees C in Cryocell 1200 programmable freezer, and stored in liquid nitrogen for periods ranging from 1 week to 6 months. Upon thawing, the straws were dipped into room temperature water for 10~20 s, after which the ovaries were collected and washed in L-15 buffer containing 10% (V/V) FBS without DMSO to remove cryoprotectant. The thawed ovaries were transplanted into kidney capsules of 8~12-week old adult B6C2F(1) female recipient mice by two protocols, with either 1 or 2 ovaries in each capsule. Upon withdrawal after at least 14 d of transplantation, only 45.00% (72/160) of the ovaries were recovered from 40 recipients transplanted with 2 ovaries in each capsule, compared to 82.50% (33/40) in 20 recipients with only 1 ovary in each capsule. The grafted ovaries exhibited similar follicular developmental progression to that of natural ovaries. There were antral follicles present in the transplanted ovaries on day 14, whose number increased more substantially on day 19 after transplantation. Following stimulation of the recipient mice with 10 IU PMSG on day 19 after xenografting, follicles further developed to preovulatory stage with appearance of cumulus oocytes and enlarged antrum. Oocytes from these fully grown antral follicles were collected and matured in vitro in modified essential medium-alpha (MEMalpha). After 16~17 h of culture, 40.90% of the oocytes exhibited germinal vesicle breakdown (GVBD) and among which 89.02% proceeded to the metaphase II (MII) stage as indicated by exclusion of the first polar body. The remaining oocytes were further cultured and 50.83% of which initiated GVBD by 20~21 h of culture, but only 21.40% of which proceeded to MII. The above results demonstrated that the primordial follicles in newborn mouse ovaries were capable of sustaining freezing and thawing, and reinitiating development following xenograft into kidney capsule in adult recipient female mice. Production of mature oocytes from such re-developed follicles following gonadotrophin priming and the subsequent oocyte in vitro maturation implied immense prospect of application of this method to preserve female germ cells, conserve endangered species, establish animal gene stock, and utilize oocytes in assisted reproductive techniques.

Cinnamon extract (traditional herb) potentiates in vivo insulin-regulated glucose utilization via enhancing insulin signaling in rats.

Cinnamon has been shown to potentiate the insulin effect through upregulation of the glucose uptake in cultured adipocytes. In the present study, we evaluated the effect of the cinnamon extract on the insulin action in awaked rats by the euglycemic clamp and further analyzed possible changes in insulin signaling occurred in skeletal muscle. The rats were divided into saline and cinnamon extract (30 and 300 mg/kg BW-doses: C30 and C300) oral administration groups. After 3-weeks, cinnamon extract treated rats showed a significantly higher glucose infusion rate (GIR) at 3 mU/kg per min insulin infusions compared with controls (118 and 146% of controls for C30 and C300, respectively). At 30 mU/kg per min insulin infusions, the GIR in C300 rats was increased 17% over controls. There were no significant differences in insulin receptor (IR)-beta, IR substrate (IRS)-1, and phosphatidylinositol (PI) 3-kinase protein content between C300 rats and controls. However, the skeletal muscle insulin-stimulated IR-beta and the IRS-1 tyrosine phosphorylation levels in C300 rats were 18 and 33% higher, respectively, added to 41% higher IRS-1/PI 3-kinase association. These results suggest that the cinnamon extract would improve insulin action via increasing glucose uptake in vivo, at least in part through enhancing the insulin-signaling pathway in skeletal muscle.

Effects of keishi-ka-jutsubu-to (traditional herbal medicine: Gui-zhi-jia-shu-fu-tang) on in vivo insulin action in streptozotocin-induced diabetic rats.

This study investigated the effects of the traditional herbal medicine, Keishi-ka-jutsubu-to (KJT) on insulin action in vivo and insulin signaling in skeletal muscle in STZ-induced diabetes. Rats were divided into single and 7-days oral administration groups. Euglycemic clamp (insulin infusion rates: 3 and 30 mU/kg/min) was used in awaked rats and the insulin signaling in skeletal muscle was evaluated. At low-dose insulin infusion, the decreased metabolic clearance rates of glucose (MCR) in diabetic rats were improved by a single and 7-days administration of KJT (800 mg/kg BW, p.o.; acute effect: 6.7 +/- 0.6 vs. 12.3 +/- 1.2, and 7-days effect: 6.3 +/- 0.5 vs. 13.9 +/- 1.0 ml/kg/min, P<0.001, respectively). During high-dose insulin infusion, the MCR was increased in 7-days KJT treated diabetes compared with saline diabetes, but, these changes were not observed after a single KJT treatment. About 90% of the increasing effect in MCR induced by the 7-days KJT treatment was blocked by L-NMMA. However, no further additive effects were seen in KJT + SNP treatment. IRbeta protein increase and decreased IRS-1 protein expression in diabetes were significantly improved by KJT treatment. KJT had no effect on the GLUT4 protein content. The increased tyrosine phosphorylation level of IRbeta, IRS-1, and IRS-1 associated with PI 3-kinase were significantly inhibited in KJT treated diabetes. The present study suggests that the improvement of impaired insulin action in STZ-diabetes by administration of KJT may be due, at least in part, to enhanced insulin signaling, which may be involved with production of nitric oxide (NO).

Cinnamon polyphenols attenuate the hydrogen peroxide-induced down regulation of S100ß secretion by regulating sirtuin 1 in C6 rat glioma cells.

AIMS: It is well established that the brain is particularly susceptible to oxidative damage due to its high consumption of oxygen. The objective of this study was to investigate the protective effects of a water soluble polyphenol-rich extract of cinnamon and the possible mechanisms, under conditions of oxidative stress-induced by hydrogen peroxide, in rat C6 glioma cells. MAIN METHODS: After 24h of H2O2 incubation, the secretion and intracellular expression of S100ß were determined by immunoprecitation/immunoblotting and immunofluorescence imaging. KEY FINDINGS: Cinnamon polyphenols (CP) counteracted the oxidative effects of H2O2 on S100ß secretion and expression. CP also enhanced the impaired protein levels of sirtuins 1, 2, and 3, which are deacetylases important in cell survival. H2O2 also induced the overexpression of the proinflammatory factors, TNF-α, phospho-NF-κB p65, as well as of Bcl-xl, Bax and Caspase-3, which are all the members of the Bcl-2 family. CP not only suppressed the expression of these proteins but also attenuated the phosphorylation induced by H2O2. CP also upregulated the decreased Bcl-2 protein levels in H2O2 treated C6 cells. The effects of CP on H2O2-induced downregulation of S100ß secretion were blocked by SIRT1 siRNA demonstrating that SIRT1 plays a regulatory role in CP-mediated prevention by H2O2. SIGNIFICANCE: These data demonstrate that Cinnamon polyphenols may exert neuroprotective effects in glial cells by the regulation of Bcl-2 family members and enhancing SIRT1 expression during oxidative stress.

Cinnamon polyphenols regulate S100ß, sirtuins, and neuroactive proteins in rat C6 glioma cells.

OBJECTIVE: Increasing evidence suggests that cinnamon has many health benefits when used in herbal medicine and as a dietary ingredient. The aim of this study was to investigate the effects of an aqueous extract of cinnamon, high in type A polyphenols, on molecular targets in rat C6 glioma cells that underlie their protective effects. METHODS: C6 rat glioma cells were seeded in 35-mm culture dishes or six-well plates, then were incubated with cinnamon polyphenols at doses of 10 and 20 µg/mL for 24 h. The targeting protein expression, secretion, and phosphorylation were evaluated by immunoprecitation/immunoblotting and immunofluorescence imaging. RESULTS: Cinnamon polyphenols significantly enhanced secretion of S100ß, a Ca(2+)-binding protein, and increased intracellular S100ß expression after 24 h of incubation, in rat C6 glioma cells. Cinnamon polyphenols also enhanced protein levels of sirtuin 1, 2, and 3, deacetylases important in cell survival, and the tumor suppressor protein, p53, and inhibited the inflammatory factors, tumor necrosis factor alpha, and phospho-p65, a subunit of nuclear factor-κß. Cinnamon polyphenols also up-regulated levels of phospho-p38, extracellular signal-regulated protein and mitogen-activated protein and kinase-activated protein kinases that may be important for prosurvival functions. CONCLUSION: Our results indicate that the effects of cinnamon polyphenols on upregulating prosurvival proteins, activating mitogen-activated protein kinase pathways, and decreasing proinflammatory cytokines may contribute to their neuroprotective effects.

Cinnamon counteracts the negative effects of a high fat/high fructose diet on behavior, brain insulin signaling and Alzheimer-associated changes.

Insulin resistance leads to memory impairment. Cinnamon (CN) improves peripheral insulin resistance but its effects in the brain are not known. Changes in behavior, insulin signaling and Alzheimer-associated mRNA expression in the brain were measured in male Wistar rats fed a high fat/high fructose (HF/HFr) diet to induce insulin resistance, with or without CN, for 12 weeks. There was a decrease in insulin sensitivity associated with the HF/HFr diet that was reversed by CN. The CN fed rats were more active in a Y maze test than rats fed the control and HF/HFr diets. The HF/HFr diet fed rats showed greater anxiety in an elevated plus maze test that was lessened by feeding CN. The HF/HFr diet also led to a down regulation of the mRNA coding for GLUT1 and GLUT3 that was reversed by CN in the hippocampus and cortex. There were increases in Insr, Irs1 and Irs2 mRNA in the hippocampus and cortex due to the HF/HFr diet that were not reversed by CN. Increased peripheral insulin sensitivity was also associated with increased glycogen synthase in both hippocampus and cortex in the control and HF/HFr diet animals fed CN. The HF/HFr diet induced increases in mRNA associated with Alzheimers including PTEN, Tau and amyloid precursor protein (App) were also alleviated by CN. In conclusion, these data suggest that the negative effects of a HF/HFr diet on behavior, brain insulin signaling and Alzheimer-associated changes were alleviated by CN suggesting that neuroprotective effects of CN are associated with improved whole body insulin sensitivity and related changes in the brain.

Cinnamon polyphenols regulate multiple metabolic pathways involved in insulin signaling and intestinal lipoprotein metabolism of small intestinal enterocytes.

OBJECTIVE: Increasing evidence suggests that dietary factors may affect the expression of multiple genes and signaling pathways, which regulate intestinal lipoprotein metabolism. The small intestine is actively involved in the regulation of dietary lipid absorption, intracellular transport, and metabolism and is closely linked to systemic lipid metabolism. Cinnamon polyphenols have been shown to improve glucose, insulin, and lipid metabolism and improve inflammation in cell culture, animal, and human studies. However, little is known of the effects of an aqueous cinnamon extract (CE) on the regulation of genes and signaling pathways related to intestinal metabolism. The aim of the study was to investigate the effects of a CE on the primary enterocytes of chow-fed rats. METHODS: Freshly isolated intestinal enterocytes were used to investigate apolipoprotein-B48 secretion by immunoprecipitation; gene expressions by quantitative reverse transcriptase-polymerase chain reaction and the protein and phosphorylation levels were evaluated by western blot and flow cytometric analyses. RESULTS: Ex vivo, the CE significantly decreased the amount of apolipoprotein-B48 secretion into the media, inhibited the mRNA expression of genes of the inflammatory cytokines, interleukin-1ß, interleukin-6, and tumor necrosis factor-α, and induced the expression of the anti-inflammatory gene, Zfp36. CE also increased the mRNA expression of genes leading to increased insulin sensitivity, including Ir, Irs1, Irs2, Pi3k, and Akt1, and decreased Pten expression. CE also inhibited genes associated with increased cholesterol, triacylglycerols, and apolipoprotein-B48 levels, including Abcg5, Npc1l1, Cd36, Mttp, and Srebp1c, and facilitated Abca1 expression. CE also stimulated the phospho-p38 mitogen-activated protein kinase, c-Jun N-terminal kinase, and extracellular-signal-regulated kinase expressions determined by flow cytometry, with no changes in protein levels. CONCLUSIONS: These results demonstrate that the CE regulates genes associated with insulin sensitivity, inflammation, and cholesterol/lipogenesis metabolism and the activity of the mitogen-activated protein kinase signal pathway in intestinal lipoprotein metabolism.

Multiple factors and pathways involved in hepatic very low density lipoprotein-apoB100 overproduction in Otsuka Long-Evans Tokushima Fatty rats.

AIMS: Overproduction of hepatic very low-density lipoprotein (VLDL) particles is a major abnormality of lipoprotein dysregulation in type 2 diabetes (T2D). We sought to examine the relationship between systemic/hepatic inflammation associated with insulin resistance and apolipoprotein (apo)B100-containing VLDL production. METHODS AND RESULTS: At the age of 19 wks, Otsuka Long-Evans Tokushima Fatty (OLETF) rats showed systemic inflammation (plasma TNF-α and interleukin (IL)-6 levels increased), insulin resistance (plasma retinol binding protein 4 and soluble CD36 levels were higher), dyslipidemia and fatty liver (plasma and liver triglyceride and cholesterol levels were higher as well as total VLDL-, VLDL(1)-, VLDL(2)-apoB100 and VLDL-triglycerides were overproduced), compared with the control rats. In livers of OLETF rats, mRNA levels of tnf, il1b and il6 were increased, but an anti-inflammatory protein, zinc finger protein 36, and its mRNA expression were decreased. We also found that the liver mRNA, protein levels, and tyrosine phosphorylation (pY) of insulin receptor (InsR) substrate (IRS) 2, but not IRS1, were decreased in OLETF rats; pY of InsR and Akt protein and phospho-Akt (ser437) were also reduced; but protein tyrosine phosphatase-1B protein was overexpressed. The gene expressions of glucose transporters 1 and 2, and glycogen synthase were decreased, but phosphatase and tensin homolog deleted on chromosome ten and glycogen synthase kinase 3ß mRNAs were overexpressed, compared with the controls. Sterol regulatory element binding protein-1c mRNA, ATP-binding cassette transporter A1 mRNA, microsomal triglyceride transfer protein mRNA/protein, and CD36 mRNA/protein levels were increased and lipoprotein lipase and Niemann-Pick c1-like1 mRNA levels were decreased, which are all involved in lipogenesis. Decreased sirtuins1-3 mRNA levels were also observed in OLETF rats. CONCLUSIONS: These abnormal genes, proteins expression and phosphorylation of multiple pathways related to inflammatory, insulin signaling and lipogenesis may be important underlying factors in VLDL-apoB100 particles overproduction observed in T2D. Our data contribute to the further understanding of an association of dyslipoproteinemia with systemic metabolic disorders, fatty liver and dysregulated hepatic metabolic pathways.