Renoprotective effects of oleanolic acid and its possible mechanisms in rats with diabetic kidney disease.

Dyslipidemia and inflammation have great roles in the development of diabetic nephropathy (DN). Oleanolic acid (OA) is a natural triterpenoid that possesses multiple pharmacological properties including anti-oxidation, anti-inflammatory and hypoglycemia. In the present study, the effects of OA on diabetic kidney disease (DKD) and its underlying mechanisms were investigated in DKD rats. Twenty-five of a total thirty-five male Sprague-Dawley (SD) rats were used to establish for Type 2 diabetes mellitus (T2DM) model by high-fat diet combined with streptozotocin (STZ). Then rats were randomly assigned into four group: control group (n = 10), T2DM group (n = 9), OA (50 mg/kg) group (n = 7), OA (100 mg/kg) group (n = 8). Rats were sacrificed at the end of 18 weeks after feeding by intraperitoneal injection of pentobarbital sodium. Body weight (BW), fasting blood glucose (FBG), kidney weight (KW), serum lipid, 24-h urinary microalbumin (UMA), serum creatinine (Scr) and uric acid (UA) were measured. Histopathological changes were observed by PAS staining and electron microscope. The expressions of nephrin, CD68, Collagen-IV, AMPK, p-AMPK, PGC-1α, TLR4, NF-κB and TGF-ß1 in kidney were also detected by immunohistochemistry or western blot. OA significantly decreased the levels of FBG, kidney index (KI), serum lipid levels, 24 h UMA, Scr, UA in diabetic rats. Additionally, OA obviously attenuated renal lipid accumulation and renal structure abnormalities in diabetic rats. Furthermore, the expression levels of nephrin, p-AMPK/AMPK, PGC-1α were elevated, while CD68, Collagen-IV, TLR4, NF-κB and TGF-ß1 expressions were decreased in renal tissues of OA treated diabetic rats. OA showed dose-independent. OA can alleviate renal injury in diabetic rats through improving lipid metabolism and inflammation via AMPK/PGC-1α and TLR4/NF-κB signaling pathway.

Effect of resveratrol on intestinal tight junction proteins and the gut microbiome in high-fat diet-fed insulin resistant mice.

High-fat diet (HFD)-feeding induces changes in the microbiome and increases intestinal permeability by impairing tight junction (TJ) protein function, which may explain the insulin resistance (IR) and associated pathologies. We aimed to determine the effects of resveratrol (RES) on the gut microbiome and intestinal TJ proteins. Results showed that RES administration improved the lipid profile, and ameliorated the endotoxemia, inflammation, intestinal barrier defect and glucose intolerance in the HFD-fed mice. Furthermore, it modified the gut microbial composition, reducing the proportion of Firmicutes and the Firmicutes-to-Bacteroidetes ratio. Moreover, Verrucomicrobia and Akkermansia were much more abundant in the HFD + RES group. RES also significantly reduced the abundance of Bilophila and Ruminococcus. These findings suggest that RES may be useful for the treatment of IR and associated metabolic diseases.

[Oxymatrine alleviates oxidative stress in fat-induced insulin resistance mice by suppressing p38MAPK pathway].

This paper was aimed to investigate the effect of oxymatrine on fat-induced insulin resistance mice（IR）, and to explore the effects of oxymatrine on oxidative stress and on p38 mitogen activated protein kinase (p38MAPK) pathway. ApoE-/- mice with high fat diet for 16 weeks were selected as IR animal model and randomly divided into the model group, oxymatrine 25, 50, 100 mg•kg⁻¹ group. C57BL/6J mice were selected as the normal control group. Mice were gavage for 8 weeks. Fasting blood glucose (FBG), cholesterol (TC), triglyceride (TG), fatty acid (FFA) and serum insulin (FINS) in the plasma were detected. Activity of superoxide dismutase (SOD), glutathione peroxidase, glutathione peroxidase (GSH-Px) and content of malondialdehyde (MDA) in liver were detected. Reactive oxygen species (ROS) content in liver cells were detected by Flow cytometry. The expression of heme oxygenase-1(HO-1), γ-glutamyl cysteine synthetase (γ-GCS) of liver was examined by Real time PCR and Western blot. The protein expression of p38MAPK, p-p38MAPK was examined by Western blot. In the study, the authors found that oxymatrine reduced the levels of FBG, TC, TG and FFA, increased SOD and GSH-Px contents, decreased MDA and ROS content. Compared with model group, HO-1, γ-GCS mRNA and protein expression significantly increased in 50, 100 mg•kg⁻¹ oxymatrine group. The expression of p-p38MAPK decreased in oxymatrine group. The results showed that oxymatrine alleviate oxidative stress in hepatic by inhibiting the phosphorylation of p38MAPK, to ameliorate fat-induced insulin resistance mice.

[Effects of Tongxinluo capsule on sciatic nerve apoptosis in spontaneous type II diabetic KK/Upj-Ay mice and mechanism research].

To investigate the effects of Tongxinluo capsule on sciatic nerve apoptosis in spontaneous type II diabetic KK/Upj-Ay mice, in order to explore its mechanism for improving diabetic peripheral neuropathy (DPN). KK/Upj-Ay mice were selected as the DPN animal model and randomly divided into the model, Tongxinluo low, middle and high group (1, 2, 4 g x kg(-1)). C57BL/6 mice were selected as the control group. Mice were given intragastrically for 12 weeks. Paw withdrawal latency, motor nerve conduction velocity (MNCV) and sensory nerve conduction velocity (SNCV) were detected. Apoptotic rate were detected by FCM. Bcl-2, Bax, Caspase-3 mRNA and protein expression in sciatic nerve were examined by Real-time PCR and Western blot. p38MAPK, p-p38MAPK expression were examined by Western blot. In this study,the authors found that Tongxinluo capsule could increase paw withdrawal latency, MNCV and SNCV. Apoptotic rate of sciatic, the expression of Bax and caspase-3 were lower, while Bcl-2 expression was higher in Tongxinluo group than those in model mice. The expression of p-p38MAPK significantly decreased in Tongxinluo group. The results showed that Tongxinluo capsule has protective effects on diabetic peripheral neuropathy of mice via inhibiting cell apoptosis and suppressing the expression of p-p38MAPK.

MiR-21 attenuates FAS-mediated cardiomyocyte apoptosis by regulating HIPK3 expression.

MicroRNA-21 (miR-21) plays an anti-apoptotic role following ischemia-reperfusion (I/R) injury (IRI) in vivo; however, its underlying mechanism remains unclear. The present study explored the effects of miR-21 and homeodomain interacting protein kinase 3 (HIPK3) on cardiomyocyte apoptosis induced by hypoxia/reoxygenation (H/R) in vitro. To this end, the rat cardiomyocyte H9C2 cell line was exposed to H/R and the roles of miR-21 and HIPK3 in regulating cell viability and apoptosis were evaluated by cell counting kit-8 assay, terminal-deoxynucleotidyl-transferase-mediated dUTP nick end labeling, and flow cytometry. Immunofluorescence and Western blotting were performed to detect the expression/phosphorylation of apoptosis-related proteins. miR-21 expression was measured with quantitative real-time polymerase chain reaction. The putative interaction between miR-21 and HIPK3 was evaluated using the luciferase reporter assay. Our results showed that (i) miR-21 overexpression or HIPK3 down-regulation significantly attenuated H9C2 cells apoptosis after H/R, (ii) suppression of miR-21 expression promoted apoptosis, (iii) miR-21 overexpression inhibited HIPK3 expression, (iv) HIPK3 was the direct and main target of miR-21, (v) miR-21/HIPK3 formed part of a reciprocal, negative feedback loop, and (vi) HIPK3 down-regulation decreased FAS-mediated apoptosis by inhibiting the phosphorylation of FADD, which subsequently inhibited the expression of BAX and cleaved caspase-3 and increased the expression of BCL2. Our study indicates that miR-21 attenuates FAS-mediated cardiomyocyte apoptosis by regulating HIPK3 expression, which could eventually have important clinical implications for patients with acute myocardial infarction.

Macrophage-specific deletion of Notch-1 induced M2 anti-inflammatory effect in atherosclerosis via activation of the PI3K-oxidative stress axis.

OBJECTIVE: Notch-1 signaling is significantly associated with the occurrence and development of atherosclerosis (AS). However, the molecular mechanisms underlying the specific deletion of Notch-1 in AS-associated macrophages are not fully understood. This study aimed to investigate the effects of Notch-1 in AS. METHODS AND RESULTS: Tissue samples were obtained from atherosclerotic segments of human carotid arteries. Immunofluorescence staining showed that Notch-1 was significantly colocalized with macrophages (CD68+), and Notch-1 staining was increased in human vulnerable plaques. Notch-1MAC-KO/ApoE-/- mice were generated in which Notch-1 was selectively inactivated in macrophages, and WT for littermate control mice (ApoE-/-/Notch-1WT). A control group was then established. All mice fed with a high-fat and Oil Red O, Movat, a-SMA, CD68, and Sirius red staining were used to evaluate the morphology. Specific deletion of Notch-1 in macrophages repressed the pathophysiology of AS. Immunofluorescent staining and Western blotting revealed that Notch-1MAC-KO repressed M1 and M2 responses in AS. Here, GSEA revealed that Notch-1 activation and PI3K signaling were statistically significantly correlated with each other, and Notch-1 was involved in the regulation of the PI3K signaling pathway. In the in vitro experiments, the secretion of Arg-1 and exosomes was classified by peritoneal macrophages of Notch-1MAC-KO/ApoE-/- and Notch-1WT/ApoE-/- mice. Immunohistochemistry staining and Western blotting were used to measure the expression levels of Notch1, PI3K, p-PI3K, AKT, p-AKT, Arg-1, IL-6, CD36, SREBP-1, CD206, iNOS, cleaved-caspase-3/-9, Bax, CD9, Alix and TSG101 in the peritoneal macrophages and exosomes, respectively. CONCLUSIONS: The specific deletion of Notch-1 in macrophage represses the formation and development of AS via the PI3K/AKT signaling pathway.

Resveratrol Alleviates Skeletal Muscle Insulin Resistance by Downregulating Long Noncoding RNA.

Long noncoding RNA (lncRNA) is a crucial factor in the progression of insulin resistance (IR). Resveratrol (RSV) exhibits promising therapeutic potential for IR. However, there are few studies on whether RSV improves IR through lncRNA. This study aimed to determine whether RSV could influence the expression of lncRNA and to elucidate the underlying mechanism. Mice were divided into three groups: control group, high-fat diet (HFD) group, and HFD + RSV group. We conducted a high-throughput sequencing analysis to detect lncRNA and mRNA expression signatures and the ceRNA-network in the skeletal muscles of mice that were fed an HFD to induce IR. Hierarchical clustering, gene enrichment, and gene ceRNA-network analyses were subsequently conducted. Differentially expressed lncRNAs were selected and validated via reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The biological functions of the selected lncRNAs were investigated by silencing the target genes via lentivirus transfection of C2C12 mouse myotube cells. RSV treatment reversed the expression of 338 mRNAs and 629 lncRNAs in the skeletal muscles of mice with HFD-induced IR. The results of the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes database analyses indicated that the differentially expressed mRNAs modulated type II diabetes mellitus. After validating randomly selected lncRNAs via RT-qPCR, we identified a novel lncRNA, NONMMUT044897.2, which was upregulated in the HFD group and reversed with RSV treatment. Additionally, NONMMUT044897.2 was proven to function as a ceRNA of microRNA- (miR-) 7051-5p. Suppressor of Cytokine Signaling 1 (SOCS1) was confirmed as a target of miR-7051-5p. We further performed lentivirus transfection to knock down NONMMUT044897.2 in vitro and found that NONMMUT044897.2 silenced SOCS1 and potentiated the insulin signaling pathway. Hence, RSV mimicked the silencing effect of lentivirus transfection on NONMMUT044897.2. Our study revealed that RSV reduced IR in mouse skeletal muscles via the regulation of NONMMUT044897.2.

Mechanism of GLP-1 Receptor Agonists-Mediated Attenuation of Palmitic Acid-Induced Lipotoxicity in L6 Myoblasts.

Methods: Cells were divided into 5 groups-control, high-fat, 10 nmol/L LR + 0.6 mmol/L palmitic acid (PA) (10LR), 100 nmol/L LR + 0.6 mmol/L PA (100LR), and 1000 nmol/L LR + 0.6 mmol/L PA (1000LR). CCK-8 method to detect cell viability, GPO-PAP enzymatic method to detect intracellular triglyceride content, and reverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) and western blotting methods to detect fatty acid translocase CD36 (FAT/CD36) and fatty acid binding protein 4 (FABP4) in L6 cells, glucose-regulated protein 78 (GRP78), glucose transporter 4 (GLUT4) expression at the mRNA and protein levels, respectively, were performed. Results: We found that after PA intervention for 24 h, the cell viability decreased significantly; the cell viability of the LR group was higher than that of the high-fat group (P < 0.01). After PA intervention, compared with those in the high-fat group, GRP-78, FAT/CD36, FABP4 mRNA ((4.36 ± 0.32 vs. 8.15 ± 0.35); (1.00 ± 0.04 vs. 2.46 ± 0.08); (2.88 ± 0.55 vs. 8.29 ± 0.52), P < 0.01) and protein ((3338.13 ± 333.15 vs. 4963.98 ± 277.29); (1978.85 ± 124.24 vs. 2676.07 ± 100.64); (3372.00 ± 219.84 vs. 6083.20 ± 284.70), both P < 0.01) expression decreased in the LR group. The expression levels of GLUT4 mRNA ((0.75 ± 0.04 vs. 0.34 ± 0.03), P < 0.01) and protein ((3443.71 ± 191.89 vs. 2137.79 ± 118.75), P < 0.01) increased. Conclusion: Therefore, we conclude that LR can reverse PA-induced cell inactivation and lipid deposition, which may be related to the change in GRP-78, FAT/CD36, FABP4, GLUT4, and other factors.

Resveratrol Ameliorates High-Fat-Diet-Induced Abnormalities in Hepatic Glucose Metabolism in Mice via the AMP-Activated Protein Kinase Pathway.

Diabetes mellitus is highly prevalent worldwide. High-fat-diet (HFD) consumption can lead to liver fat accumulation, impair hepatic glycometabolism, and cause insulin resistance and the development of diabetes. Resveratrol has been shown to improve the blood glucose concentration of diabetic mice, but its effect on the abnormal hepatic glycometabolism induced by HFD-feeding and the mechanism involved are unknown. In this study, we determined the effects of resveratrol on the insulin resistance of high-fat-diet-fed mice and a hepatocyte model by measuring serum biochemical indexes, key indicators of glycometabolism, glucose uptake, and glycogen synthesis in hepatocytes. We found that resveratrol treatment significantly ameliorated the HFD-induced abnormalities in glucose metabolism in mice, increased glucose absorption and glycogen synthesis, downregulated protein phosphatase 2A (PP2A) and activated Ca2+/CaM-dependent protein kinase kinase ß (CaMKKß), and increased the phosphorylation of AMP-activated protein kinase (AMPK). In insulin-resistant HepG2 cells, the administration of a PP2A activator or CaMKKß inhibitor attenuated the effects of resveratrol, but the administration of an AMPK inhibitor abolished the effects of resveratrol. Resveratrol significantly ameliorates abnormalities in glycometabolism induced by HFD-feeding and increases glucose uptake and glycogen synthesis in hepatocytes. These effects are mediated through the activation of AMPK by PP2A and CaMKKß.

A high-fructose diet in rats induces systemic iron deficiency and hepatic iron overload by an inflammation mechanism.

Nonalcoholic fatty liver disease (NAFLD) correlates with the high intake of fructose-rich soft drinks. Both inflammation and dysregulated iron metabolism are pathogenic factors in the development of NAFLD. The present investigation assessed the effects of a high-fructose diet (HF diet) on inflammation and iron metabolism. In this study, rats were fed a control or HF diet for 4, 8, or 12 weeks, after which insulin resistance, transaminases levels, serum and liver lipid profiles, inflammatory factors, and iron metabolism-related molecules were evaluated. The activities of the hepatic inflammation-associated pathways, IKKß/NF-κB, and JAK2/STAT3, were detected by western blot. Result showed that the HF diet-fed animals developed a time-dependent serum lipid increase and hepatic lipid accumulation as well as insulin resistance. Serum iron (SI), serum ferritin (SF), and transferrin saturation (TS) decreased while total iron-binding capacity (TIBC) and serum transferrin (s-TF) increased at 8 and 12 weeks in the HF diet group. The HF diet led to increased transaminases levels at 8 and 12 weeks, and iron deposition was observed in the liver, accompanied by an upregulation of ferritin light chain (FTL), hepcidin (HEPC), transferrin (TF), transferrin receptor 1 (TfR1), iron regulatory protein 1 (IRP1), hemojuvelin (HJV), and divalent metal transporter 1 (DMT1). Moreover, ferroportin (FPN1) levels were downregulated, as expected from the increased HEPC. A progressive inflammation phenotype was apparent, with increased inflammatory factors, MDA, IL-1ß, IL-6, and TNF-α, in the serum and liver tissue. Concomitantly, the hepatic IKKß/NF-κB and JAK2/STAT3 pathways were activated. In summary, we verified that HF diet induces systemic iron deficiency and hepatic iron accumulation, likely due to the activation of inflammation via the NF-κB and JAK2/STAT3 pathways. PRACTICAL APPLICATIONS: As increasing numbers of individuals consume HF diets, the health implications of this type of over nutrition become globally relevant. Using a high-fructose diet rat model, our present study reveals inflammation as the link between a HF diet and dysregulated iron metabolism. Importantly, both inflammation and disrupted iron metabolism have been shown to be pathogenic factors in nonalcoholic fatty liver disease (NAFLD). The iron regulatory hormone, HEPC, is a link between the liver, inflammation, and iron metabolism. As fructose-rich foods become increasingly abundant and people's fructose intake increases, the impact of high fructose on health requires increased attention. Little research has been conducted on the effects of fructose on iron metabolism. Our study provides useful insights into the prevention and treatment of iron metabolism disorders arising from metabolic syndrome.

BRAFV600E mutant colorectal cancer cells mediate local immunosuppressive microenvironment through exosomal long noncoding RNAs.

BACKGROUND: BRAFV600E mutated colorectal cancer (CRC) is prone to peritoneal and distant lymph node metastasis and this correlates with a poor prognosis. The BRAFV600E mutation is closely related to the formation of an immunosuppressive microenvironment. However, the correlation between BRAFV600E mutation and changes in local immune microenvironment of CRC is not clear. AIM: To explore the effect and mechanism of BRAFV600E mutant on the immune microenvironment of CRC. METHODS: Thirty patients with CRC were included in this study: 20 in a control group and 10 in a treatment group. The density of microvessels and microlymphatic vessels, and M2 subtype macrophages in tumor tissues were detected by immunohistochemistry. Screening and functional analysis of exosomal long noncoding RNAs (lncRNAs) were performed by transcriptomics. The proliferation and migration of human umbilical vein endothelial cells (HUVECs) and human lymphatic endothelial cells (HLECs) were detected by CCK-8 assay and scratch test, respectively. The tube-forming ability of endothelial cells was detected by tube formation assay. The macrophage subtypes were obtained by flow cytometry. The expression of vascular endothelial growth factor (VEGF)-A, basic fibroblast growth factor (bFGF), transforming growth factor (TGF)-ß1, VEGF-C, claudin-5, occludin, zonula occludens (ZO)-1, fibroblast activation protein, and α-smooth muscle actin was assessed by western blot analysis. The levels of cytokines interleukin (IL)-6, TGF-ß1, and VEGF were assessed by enzyme-linked immunosorbent assay. RESULTS: BRAFV600E mutation was positively correlated with the increase of preoperative serum carbohydrate antigen 19-9 (P < 0.05), and with poor tumor tissue differentiation in CRC (P < 0.01). Microvascular density and microlymphatic vessel density in BRAFV600E mutant CRC tissues were higher than those in BRAF wild-type CRC (P < 0.05). The number of CD163+ M2 macrophages in BRAFV600E mutant CRC tumor tissue was markedly increased (P < 0.05). Compared with exosomes from CRC cells with BRAF gene silencing, the expression of 13 lncRNAs and 192 mRNAs in the exosomes from BRAFV600E mutant CRC cells was upregulated, and the expression of 22 lncRNAs and 236 mRNAs was downregulated (P < 0.05). The biological functions and signaling pathways predicted by differential lncRNA target genes and differential mRNAs were closely related to angiogenesis, tumor cell proliferation, differentiation, metabolism, and changes in the microenvironment. The proliferation, migration, and tube formation ability of HUVECs and HLECs induced by exosomes in the 1627 cell group (HT29 cells with BRAF gene silencing) was greatly reduced compared with the HT29 cell group (P < 0.05). Compared with the HT29 cell group, the expression levels of VEGF-A, bFGF, TGF-ß1, and VEGF-C in the exosomes derived from 1627 cells were reduced. The expression of ZO-1 in HUVECs, and claudin-5, occludin, and ZO-1 in HLECs of the 1627 cell group was higher. Compared with the 1627 cell group, the exosomes of the HT29 cell group promoted the expression of CD163 in macrophages (P < 0.05). IL-6 secretion by macrophages in the HT29 cell group was markedly elevated (P < 0.05), whereas TGF-ß1 was decreased (P < 0.05). The levels of IL-6, TGF-ß1, and VEGF secreted by fibroblasts in the 1627 cell group decreased, compared with the HT29 cell group (P < 0.05). CONCLUSION: BRAFV600E mutant CRC cells can reach the tumor microenvironment by releasing exosomal lncRNAs, and induce the formation of an immunosuppressive microenvironment.

Exploring the Multi-Tissue Crosstalk Relevant to Insulin Resistance Through Network-Based Analysis.

Insulin resistance (IR) is a precursor event that occurs in multiple organs and underpins many metabolic disorders. However, due to the lack of effective means to systematically explore and interpret disease-related tissue crosstalk, the tissue communication mechanism in pathogenesis of IR has not been elucidated yet. To solve this issue, we profiled all proteins in white adipose tissue (WAT), liver, and skeletal muscle of a high fat diet induced IR mouse model via proteomics. A network-based approach was proposed to explore IR related tissue communications. The cross-tissue interface was constructed, in which the inter-tissue connections and also their up and downstream processes were particularly inspected. By functional quantification, liver was recognized as the only organ that can output abnormal carbohydrate metabolic signals, clearly highlighting its central role in regulation of glucose homeostasis. Especially, the CD36-PPAR axis in liver and WAT was identified and verified as a potential bridge that links cross-tissue signals with intracellular metabolism, thereby promoting the progression of IR through a PCK1-mediated lipotoxicity mechanism. The cross-tissue mechanism unraveled in this study not only provides novel insights into the pathogenesis of IR, but also is conducive to development of precision therapies against various IR associated diseases. With further improvement, our network-based cross-tissue analytic method would facilitate other disease-related tissue crosstalk study in the near future.

MicroRNA­802 increases hepatic oxidative stress and induces insulin resistance in high­fat fed mice.

The expression of microRNA­802 (miR­802) is known to be associated with insulin resistance (IR); however, the mechanism remains unclear. The present study investigated how miR­802 contributes to the development of IR using C57BL/6J mice fed a high­fat diet (HFD) to establish a model of IR. Adeno­associated virus overexpressing miR­802 was administered to the mice via tail vein injection. The effects of miR­802 on reactive oxygen species (ROS), lipid peroxidation (LPO) and the activities of multiple ROS­related enzymes were investigated. Western blot analysis was used to estimate the protein levels of extracellular signal regulated kinase (ERK), p38mitogen­activated protein kinases (p38MAPK), c­Jun N­terminal kinase (JNK), insulin receptor substrate 1 (IRS­1) and protein kinase B (AKT1). The results demonstrated that the levels of ROS and LPO production were increased in the livers of the miR­802­treated group compared with the control group. The activities of the ROS­related enzymes were reduced. Furthermore, the expression of phosphorylated (phosphor)­p38MAPK and phosphor­JNK were upregulated in the miR­802 overexpression group, whereas there was no difference in the expression levels of phosphor­ERK. The expression levels of phosphor­AKT1 were reduced in the miR­802­treated group and these effects were reversed by miR­802 knockdown. In conclusion, the results demonstrate that miR­802 may cause IR by activating the JNK and p38MAPK pathways to increase hepatic oxidative stress.

DL-3-n-butylphthalide protects the blood-brain barrier against ischemia/hypoxia injury via upregulation of tight junction proteins.

BACKGROUND: The increased permeability of the blood-brain barrier (BBB) induced by ischemia/hypoxia is generally correlated with alteration of tight junctions (TJs). DL-3-n-butylphthalide (NBP) has been shown to exert neuroprotective effects after ischemic injury. However, few studies have assessed the correlation between NBP and TJs. This study aimed to investigate the potential effect of NBP on the TJ proteins claudin-5, zonula occludens-1 (ZO-1), and occludin during brain ischemia. METHODS: A chronic cerebral hypoperfusion (CCH) Sprague-Dawley rat model was established, and NBP (20, 40, or 80 mg/kg, gavage, once a day) treatment was performed for 14 days. NBP (0.1 or 1.0 µmol/L) pre-treatment was applied to an in vitro hypoxia microvascular endothelial cell model (1% O2, 24 h). BBB permeability was assessed by performing the Evans blue assay. The expressions and localization of claudin-5, ZO-1, occludin, phosphorylated/total protein kinase B (p-Akt/Akt), phosphorylated/total glycogen synthase kinase 3ß (GSK-3ß)/GSK-3ß, and ß-catenin/ß-actin were evaluated by Western blotting or immunofluorescence. Reactive oxygen species (ROS) generation was measured by flow cytometry analysis. TJ ultrastructure was observed by transmission electron microscopy. RESULTS: In CCH rats, treatment with 40 and 80 mg/kg NBP decreased the Evans blue content in brain tissue (9.0 ±â€Š0.9 µg/g vs. 12.3 ±â€Š1.9 µg/g, P = 0.005; 6.7 ±â€Š0.6 µg/g vs. 12.3 ±â€Š1.9 µg/g, P < 0.01), increased the expression of claudin-5 (0.79 ±â€Š0.08 vs. 0.41 ±â€Š0.06, P < 0.01; 0.97 ±â€Š0.07 vs. 0.41 ±â€Š0.06, P < 0.01), and elevated the ZO-1 protein level (P < 0.05) in brain microvascular segments in a dose-dependent manner in comparison with the corresponding values in the model group. There was no significant difference in occludin expression (P > 0.05). In the hypoxia cell model, NBP pre-treatment improved TJ ultrastructure, decreased intracellular ROS level, and increased the expression of claudin-5 (P < 0.01) and ZO-1 (P < 0.01) in comparison with the corresponding values in the hypoxia group. NBP treatment also elevated the relative expression levels of p-Akt/Akt, p-GSK-3ß/GSK-3ß, and ß-catenin/ß-actin in comparison with the corresponding values in the hypoxia group (all P < 0.05). CONCLUSION: NBP improves the barrier function of BBB against ischemic injury by upregulating the expression of TJ proteins, possibly by reducing oxidative stress and activating the Akt/GSK-3ß/ß-catenin signaling pathway.

Hemin, a heme oxygenase-1 inducer, improves aortic endothelial dysfunction in insulin resistant rats.

BACKGROUND: Under an insulin resistance (IR) state, overproduction of reactive oxygen species (ROS) may be playing a major role in the pathogenesis of endothelial dysfunction, hypertension and atherosclerosis. Recently, increasing attention has been drawn to the beneficial effects of heme oxygenase-1 (HO-1) in the cardiovascular system. This study aimed to investigate the effects of HO-1 on vascular function of thoracic aorta in IR rats and demonstrate the probable mechanisms of HO-1 against endothelial dysfunction in IR states. METHODS: Sprague-Dawley (SD) rats fed with high-fat diet for 6 weeks and the IR models were validated with hyperinsulinemic-euglycemic clamp test. Then the IR rat models (n = 44) were further randomized into 3 subgroups, namely, the IR control group (n = 26, in which 12 were sacrificed immediately and evaluated for all study measures), a hemin treated IR group (n = 10) and a zinc protoporphyrin-IX (ZnPP-IX) treated IR group (n = 8) that were fed with a high-fat diet. Rats with standardized chow diet were used as the normal control group (n = 12). The rats in IR control group, hemin treated IR group and ZnPP-IX treated IR group were subsequently treated every other day with an intraperitoneal injection of normal saline, hemin (inducer of HO-1, 30 micromol/kg) or ZnPP-IX (inhibitor of HO-1, 10 micromol/kg) for 4 weeks. Rats in the normal control group remained on a standardized chow diet and were treated with intraperitoneal injections of normal saline every other day for 4 weeks. Systolic arterial blood pressure (SABP) was measured by tail-cuffed microphotoelectric plethysmography. The blood carbon monoxide (CO) was measured by blood gas analysis. The levels of nitric oxide (NO), inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), blood glucose (BG), insulin, total cholesterol (TC) and triglyceride (TG) in serum, and the levels of total antioxidant capacity (TAOC), malondialdehyde (MDA) and superoxide dismutase (SOD) in the aorta were measured. The expression of HO-1 mRNA and HO-1 protein in aortal tissue were detected by semi-quantitative RT-PCR and Western blot. The vasoreactive tensometry was performed with thoracic aortic rings (TARs). RESULTS: Compared with the normal control group, the levels of SABP, BG, insulin, TC, TG, NO, iNOS and MDA were higher, while the levels of CO, TAOC, SOD and eNOS were lower in IR control rats. After treatment of IR rats for 4 weeks a more intensive expression of HO-1 mRNA and HO-1 protein were observed in hemin treated IR group compared with the normal control group. And compared with 4-week IR control rats, the levels of CO, TAOC, SOD and eNOS were increased, while the levels of SABP and iNOS activity were lower in the hemin treated IR group. Administration of hemin in IR rats appeared to improve the disordered vasorelaxation of TARs to acetylcholine (ACh). Alternatively, the reverse results of SABP, CO, TAOC, SOD, iNOS and vasorelaxation responses to ACh were observed in IR rats with administration of ZnPP-IX. CONCLUSIONS: The endothelial dysfunction in the aorta is present in the IR state. The protective effects of HO-1 against aortic endothelial dysfunction may be due to its antioxidation and regulative effect of vasoactive substances. It is proposed that hemin, inducer of HO-1, could be a potential therapeutic option for vascular dysfunction in IR states.

Role of X-Box Binding Protein-1 in Fructose-Induced De Novo Lipogenesis in HepG2 Cells.

BACKGROUND: A high consumption of fructose leads to hepatic steatosis. About 20-30% of triglycerides are synthesized via de novo lipogenesis. Some studies showed that endoplasmic reticulum stress (ERS) is involved in this process, while others showed that a lipotoxic environment directly influences ER homeostasis. Here, our aim was to investigate the causal relationship between ERS and fatty acid synthesis and the effect of X-box binding protein-1 (XBP-1), one marker of ERS, on hepatic lipid accumulation stimulated by high fructose. METHODS: HepG2 cells were incubated with different concentrations of fructose. Upstream regulators of de novo lipogenesis (i.e., carbohydrate response element-binding protein [ChREBP] and sterol regulatory element-binding protein 1c [SREBP-1c]) were measured by polymerase chain reaction and key lipogenic enzymes (acetyl-CoA carboxylase [ACC], fatty acid synthase [FAS], and stearoyl-CoA desaturase-1 [SCD-1]) by Western blotting. The same lipogenesis-associated factors were then evaluated after exposure of HepG2 cells to high fructose followed by the ERS inhibitor tauroursodeoxycholic acid (TUDCA) or the ERS inducer thapsigargin. Finally, the same lipogenesis-associated factors were evaluated in HepG2 cells after XBP-1 upregulation or downregulation through cell transfection. RESULTS: Exposure to high fructose increased triglyceride levels in a dose- and time-dependent manner and significantly increased mRNA levels of SREBP-1c and ChREBP and protein levels of FAS, ACC, and SCD-1, concomitant with XBP-1 conversion to an active spliced form. Lipogenesis-associated factors induced by high fructose were inhibited by TUDCA and induced by thapsigargin. Triglyceride level in XBP-1-deficient group decreased significantly compared with high-fructose group (4.41 ± 0.54 µmol/g vs. 6.52 ± 0.38 µmol/g, P < 0.001), as mRNA expressions of SREBP-1c (2.92 ± 0.46 vs. 5.08 ± 0.41, P < 0.01) and protein levels of FAS (0.53 ± 0.06 vs. 0.85 ± 0.05, P = 0.01), SCD-1 (0.65 ± 0.06 vs. 0.90 ± 0.04, P = 0.04), and ACC (0.38 ± 0.03 vs. 0.95 ± 0.06, P < 0.01) decreased. Conversely, levels of triglyceride (4.22 ± 0.54 µmol/g vs. 2.41 ± 0.35 µmol/g, P < 0.001), mRNA expression of SREBP-1c (2.70 ± 0.33 vs. 1.00 ± 0.00, P < 0.01), and protein expression of SCD-1 (0.93 ± 0.06 vs. 0.26 ± 0.05, P < 0.01), ACC (0.98 ± 0.09 vs. 0.43 ± 0.03, P < 0.01), and FAS (0.90 ± 0.33 vs. 0.71 ± 0.02, P = 0.04) in XBP-1s-upregulated group increased compared with the untransfected group. CONCLUSIONS: ERS is associated with de novo lipogenesis, and XBP-1 partially mediates high-fructose-induced lipid accumulation in HepG2 cells through augmentation of de novo lipogenesis.

Role of CXCL12 in metastasis of human ovarian cancer.

BACKGROUND: In a previous study, we have verified that CXCR4 expression is correlated with tumor aggressive progression and poor prognosis in patients with epithelial ovarian cancer. The aim of this study was to explore the effect of CXCL12-CXCR4 axis on the metastasis of human ovarian cancer. METHODS: The expressions of CXCR4 and CXCL12 mRNA and protein in human ovarian cancer cell line CAOV-3 was detected by RT-PCR and immunocytochemistry. Methythiazolyltetrazolium (MTT) was used to analyze the effect of different concentrations of CXCL12 on the proliferation of CAOV-3 cells. Transwell invasion chamber and matrigel were used to evaluate the effect of various concentrations of CXCL12 and ascites on the migration and invasion of CAOV-3 cells. The expressions of integrin beta(1) and vascular endothelial growth factor-C (VEGF-C) mRNA were detected by RT-PCR. Data were analyzed using ANOVA by SAS 6.12. RESULTS: Under serum-free suboptimal culture conditions, CXCL12 (100 ng/ml) significantly enhanced the proliferation of CAOV-3 cells compared with the control and 10 ng/ml CXCL12 groups (0.428 +/- 0.051 vs. 0.325 +/- 0.045 and 0.328 +/- 0.039, P < 0.05). This enhancing effect of CXCL12 was significantly inhibited by 10 microg/ml neutralizing CXCR4 antibody or 1 microg/ml CXCR4 antagonist AMD3100. However, 10 microg/ml neutralizing CXCR4 antibody could not inhibit cell proliferation without CXCL12. The levels of migration and invasion of the CAOV-3 cells treated with 100 ng/ml CXCL12 were significantly higher than those in the control (migration: 523.3 +/- 25.2 vs 108.0 +/- 7.2; invasion: 39.3 +/- 4.0 vs. 4.0 +/- 1.0). The enhancing effect of CXCL12 on cell migration and invasion increased with the concentration of CXCL12 (100 ng/ml vs10 ng/ml: migration, 523.3 +/- 25.2 vs 211.7 +/- 24.7; invasion, 39.3 +/- 4.0 vs 15.7 +/- 3.1, P < 0.05), and was strongly inhibited by 10 microg/ml neutralizing CXCR4 antibody or 1 microg/ml AMD3100. The number of migrated and invading cells in the CAOV-3 added with ascites was significantly higher than those in the 100 ng/ml CXCL12 group (migration: 706.6 +/- 30.6 vs 523.3 +/- 25.2, invasion: 61.7 +/- 7.6 vs 39.3 +/- 4.0, P < 0.05). The level of integrin beta(1) mRNA was greatly increased at 3 hours after being treated with CXCL12 (0.53 +/- 0.10 vs. 1.53 +/- 0.16, P < 0.05), and VEGF-C mRNA displayed significant augment at 24 hours after being treated with CXCL12 (0.52 +/- 0.09 vs 1.11 +/- 0.15, P < 0.05). CONCLUSIONS: CXCL12 and its receptor CXCR4 can promote the proliferation, migration, invasion of ovarian cancer cell line CAOV-3 and enhance its secretion of integrin beta(1) and VEGF-C. These effects can be inhibited by neutralizing CXCR4 antibody or AMD3100. CXCL12-CXCR4 axis plays an important role in ovarian cancer growth and metastasis.

[Effect of chemokine CXCL12 and its receptor CXCR4 on proliferation, migration and invasion of epithelial ovarian cancer cells].

OBJECTIVE: To explore the effect of chemokine CXCL12 and its receptor CXCR4 on proliferation, migration and invasion of epithelial ovarian cancer cells. METHODS: CXCR4 and CXCL12 mRNA and protein expression of human ovarian cancer cell line CAOV3 was detected by RT-PCR and immunocytochemistry. Integrin beta1 and vascular endothelial growth factor-C (VEGF-C) mRNA expression were detected in CAOV3 cells stimulated by CXCL12. The CAOV3 cells were divided into 6 groups: control group (un-stimulated), experimental group 1 (stimulated by 100 ng/ml CXCL12), experimental group 2 (stimulated by 10 ng/ml CXCL12), experimental group 3 (100 ng/ml CXCL12 and 10 microg/ml neutralizing CXCR4 antibody), experimental group 4 (100 ng/ml CXCL12 and 1 microg/ml CXCR4 antagonist AMD3100), experimental group 5 (10 microg/ml neutralizing CXCR4 antibody or ascites). Methyl thiazolyl tetrazolium (MTT) was used to analyze the effects of different concentrations of CXCL12 on CAOV3 cell proliferation. Transwell invasion chamber and reconstructed basement membrane (Matrigel) were used to evaluate effect of various concentrations of CXCL12 and ascites on CAOV3 cell migration and invasion. RESULTS: CAOV3 cells expressed CXCR4 mRNA (0.70 +/- 0.10) and protein, but did not express CXCL12 mRNA or protein. Immunostaining of CXCR4 was mainly located in cytoplasm. CXCR4 mRNA was up-regulated after 100 ng/ml CXCL12 stimulation (1.24 +/- 0.14; t = -7.1088, P = 0.0021). Integrin beta1 mRNA was greatly increased at 3 hours by stimulation of 100 ng/ml CXCL12 (before and after stimulation 0.53 +/- 0.10, 1.53 +/- 0.16; P < 0.01), and VEGF-C mRNA showed significant increase at 24 hours by treatment with CXCL12 (before and after stimulation 0.52 +/- 0.09, 1.11 +/- 0.15; P < 0.05). Under serum-free sub-optimal culture conditions, experimental group 1 greatly enhanced cell proliferation in CAOV3 cells compared with control group and experimental group 2 (respectively 0.428 +/- 0.051, 0.325 +/- 0.045, 0.328 +/- 0.039; P < 0.05). Experimental group 1 was strongly inhibited compared with experimental groups 3 and 4 (the latter two groups respectively 0.356 +/- 0.031, 0.373 +/- 0.029; P < 0.05). There was no significant difference between experimental group 5 (0.349 +/- 0.038) and control group (P > 0.05). Experimental group 1 stimulated the migration and invasion of CAOV3 cells in chemotaxis assay compared with control group and experimental group 2 (number of cell migration respectively 523.3 +/- 25.2, 108.0 +/- 7.2, 211.7 +/- 24.7, number of cell invasion respectively 39.3 +/- 4.0, 4.0 +/- 1.0, 15.7 +/- 3.1; P < 0.01). This enhancing effect of experimental group 1 was strongly inhibited compared with experimental groups 4 and 5 (P < 0.05). The number of migrating and invading cells in experimental group 5 (migration: 706.6 +/- 30.6, invasion: 61.7 +/- 7.6) was significantly higher than that of experimental group 1 (P < 0.05). CONCLUSIONS: This in vitro study shows CXCL12 promote proliferation, migration, invasion of ovarian cancer cell line CAOV3, and up-regulate integrin beta1 and VEGF-C expression, and these effects are strongly inhibited by neutralizing CXCR4 antibody. It suggests CXCL12 and its receptor CXCR4 may play important roles in ovarian cancer growth and metastasis.

Exogenous lipids promote the growth of breast cancer cells via CD36.

Cancer cells present sustained de novo fatty acid (FA) synthesis with increased production of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs). This change in FA metabolism is associated with overexpression of stearoyl-CoA desaturase 1 (SCD1), which catalyses the transformation of SFAs into MUFAs (e.g., oleic acid). In this study, we provide new evidence that SCD1 inhibition leads to the anti-proliferation effect of breast cancer cells through induction of apoptosis, cell cycle arrest and migration prevention. However, the antitumor effect of the SCD1 inhibitor can be reversed by exogenous oleic acid. We hypothesize that, in addition to de novo synthesis, cancer cells may uptake exogenous FAs actively. CD36, also known as FA translocase (FAT), that functions as a transmembrane protein and mediates the uptake of FAs, is observed to be highly expressed in breast cancer tissues. Furthermore, the anti-proliferation effect caused by the SCD1 inhibitor can not be reversed by exogenous oleic acid supplementation in CD36 knockdown breast cancer cells. Our study revealed that the lipid metabolism of breast cancer is regulated not only by de novo lipogenesis but also by the availability of lipids outside cancer cells. Consistent with FA synthesis, FA uptake and transport will be another important target pathway for anticancer therapy, and the FA channel protein CD36 may provide a promising therapeutic target. Lipogenesis combined with FA transport will be a new orientation for antitumor therapy.

Cholecystokinin octapeptide improves cardiac function by activating cholecystokinin octapeptide receptor in endotoxic shock rats.

AIM: To explore the effect of sulfated cholecystokinin octapeptide (sCCK-8) on cardiac functions and its receptor mechanism in endotoxic shock (ES) rats. METHODS: The changes of the mean arterial pressure (MAP), heart rate (HR), the left ventricular pressure (LVP) and the maximal/minimum rate of LVP (+/-LVdp/dt(max))) were measured by using physiological record instrument in eight groups of rats. The expression of cholecystokinin-A receptor (CCK-AR) and cholecystokinin-B receptor (CCK-BR) mRNA of myocardium in ES rats was examined by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: (1) Low doses of sCCK-8 (0.4 microg/kg) caused tachycardia (441+/-27, normal control 391+/-22 s/min) and slight increase in MAP, LVP and +/-LVdp/dt(max) (16.96+/-1.79, 18.21+/-1.69 and +768.85+/-31.28/-565.04+/-27.71 kPa, respectively, all P<0.01), while medium doses (4.0 microg/kg) and high doses of sCCK-8 (40 microg/kg) elicited bradycardia and marked increase in MAP, LVP and +/-LVdp/dt(max) (17.29+/-1.63, 19.46+/-2.57 and +831.46+/-22.57/-606.08 +/-31.32; 17.46+/-1.08, 19.83+/-2.91 and +914.52+/-35.95/-639.15+/-30.23 kPa, respectively, all P<0.01). Proglumide (1.0 mg/kg), a nonselective antagonist of CCK-receptor (CCK-R), significantly inhibited the pressor effects of sCCK-8 (15.96+/-1.38, 17.36+/-0.66 and +748.18+/-19.29/-512.12+/-14.39 kPa, respectively, all P<0.01), whilst reversing the bradycardiac responses. (2) High doses of LPS (8 mg/kg) elicited marked decrease in MAP, LVP and +/-LVdp/dt(max). (7.16+/-0.59, 7.6+/-0.68 and +298.01+/-25.52/-166.96+/-19.25 kPa, respectively, all P<0.01). Pretreatment with sCCK-8 (40 microg/kg) could reverse the decline of cardiac functions (10.71+/-0.45, 11.7+/-1.26 and +446.04+/-67.18/-347.90+/-36.98 kPa, respectively, all P<0.01), while proglumide could cause further decline of cardiac function in ES rats (4.71+/-0.67, 5.58+/-1.25 and +226.48+/-15.84/-142.83+/-20.23 kPa, respectively, all P<0.01). (3) CCK-A/BR mRNAs were expressed in myocardium of control rats. Gene expression of CCK-AR and CCK-BR significantly increased in myocardium of ES rats. The increase of CCK-AR mRNA induced by LPS began at 0.5 h, peaked at 2 h, kept a high level at 6 h and declined at 12 h, respectively. Similar to CCK-AR mRNA, the expression of CCK-BR mRNA peaked at 2 h and kept a high level at 6 h, but it did not change at the first 0.5 h and was stable at a high level at 12 h. CONCLUSION: The above results indicate that endogenous and exogenous sCCK-8 may significantly improve cardiac function and intractable hypotension of ES rats, which was likely related to high expression of CCK-A/BR in myocardium induced by LPS.