Effects of Low-Molecular-Weight Fucoidan and High Stability Fucoxanthin on Glucose Homeostasis, Lipid Metabolism, and Liver Function in a Mouse Model of Type II Diabetes.

The combined effects of low-molecular-weight fucoidan (LMF) and fucoxanthin (Fx) in terms of antihyperglycemic, antihyperlipidemic, and hepatoprotective activities were investigated in a mouse model of type II diabetes. The intake of LMF, Fx, and LMF + Fx lowered the blood sugar and fasting blood sugar levels, and increased serum adiponectin levels. The significant decrease in urinary sugar was only observed in LMF + Fx supplementation. LMF and Fx had ameliorating effects on the hepatic tissue of db/db mice by increasing hepatic glycogen and antioxidative enzymes, and LMF was more effective than Fx at improving hepatic glucose metabolism. As for glucose and lipid metabolism in the adipose tissue, the expression of insulin receptor substrate (IRS)-1, glucose transporter (GLUT), peroxisome proliferator-activated receptor gamma (PPARγ), and uncoupling protein (UCP)-1 mRNAs in the adipose tissue of diabetic mice was significantly upregulated by Fx and LMF + Fx, and levels of inflammatory adipocytokines, such as adiponectin, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6), were significantly modulated only by LMF + Fx supplementation. The efficacy of LMF + Fx supplementation on the decrease in urinary sugar and on glucose and lipid metabolism in the white adipose tissue of db/db mice was better than that of Fx or LMF alone, indicating the occurrence of a synergistic effect of LMF and Fx.

Autocrine CCL2 promotes cell migration and invasion via PKC activation and tyrosine phosphorylation of paxillin in bladder cancer cells.

The amount of monocyte chemoattractant protein-1 (MCP-1/CCL2) produced by a transitional cell carcinoma is directly correlated with high recurrence and poor prognosis in bladder cancer. However, the mechanisms underlying the effects of CCL2 on tumor progression remain unexplored. To investigate the role played by CCL2, we examined cell migration in various bladder cancer cell lines. We found that high-grade cancer cells expressing high levels of CCL2 showed more migration activity than low-grade bladder cancer cells expressing low levels of the chemokine. Although the activation of CCL2/CCR2 signals did not appreciably affect cell growth, it mediated cell migration and invasion via the activation of protein kinase C and phosphorylation of tyrosine in paxillin. Blocking CCL2 and CCR2 with small hairpin RNA (shCCL2) or a specific inhibitor reduced CCL2/CCR2-mediated cell migration. The antagonist of CCR2 promoted the survival of mice bearing MBT2 bladder cancer cells, and CCL2-depleted cells showed low tumorigenicity compared with shGFP cells. In addition to observing high-levels of CCL2 in high-grade human bladder cancer cells, we showed that the CCL2/CCR2 signaling pathway mediated migratory and invasive activity, whereas blocking the pathway decreased migration and invasion. In conclusion, high levels of CCL2 expressed in bladder cancer mediates tumor invasion and is involved with advanced tumorigenesis. Our findings suggest that this CCL2/CCR2 pathway is a potential candidate for the attenuation of bladder cancer metastases.

Down-regulation of BNIP3 by olomoucine, a CDK inhibitor, reduces LPS- and NO-induced cell death in BV2 microglial cells.

Proinflammatory responses eliciting the microglial production of cytokines and nitric oxide (NO) have been reported to play a crucial role in the acute and chronic pathogenic effects of neurodegeneration. Chemical inhibitors of cyclin-dependent kinases (CDKs) may prevent the progression of neurodegeneration by both limiting cell proliferation and reducing cell death. However, the mechanism underlying the protective effect of CDK inhibitors on microglia remains unexplored. In this study, we found that olomoucine, a CDK inhibitor, alleviated lipopolysaccharide (LPS)-induced BV2 microglial cell death by reducing the generation of NO and inhibiting the gene expression of proinflammatory cytokines. In addition, olomoucine reduced inducible NO synthase promoter activity and alleviated NF-κB- and E2F-mediated transcriptional activation. NO-induced cell death involved mitochondrial disruptions such as cytochrome c release and loss of mitochondrial membrane potential, and pretreatment with olomoucine prior to NO exposure reduced these disruptions. Microarray analysis revealed that olomoucine treatment induced prominent down-regulation of Bcl2/adenovirus E1B 19-kDa-interacting protein 3 (BNIP3), a pro-apoptotic Bcl-2 family protein that is involved in mitochondrial disruption. As BNIP3 knock-down significantly increased the viability of LPS- and NO-treated BV2 cells, we conclude that olomoucine may protect cells by limiting proinflammatory responses, thereby reducing NO generation. Simultaneously, down-regulation of BNIP3 prevents NO stimulation from inducing mitochondrial disruption.

Nitric oxide suppresses LPS-induced inflammation in a mouse asthma model by attenuating the interaction of IKK and Hsp90.

A feature of allergic airway disease is the observed increase of nitric oxide (NO) in exhaled breath. Gram-negative bacterial infections have also been linked with asthma exacerbations. However, the role of NO in asthma exacerbations with gram-negative bacterial infections is still unclear. In this study, we examined the role of NO in lipopolysaccharide (LPS)-induced inflammation in an ovalbumin (OVA)-challenged mouse asthma model. To determine whether NO affected the LPS-induced response, a NO donor (S-nitroso-N-acetylpenicillamine, SNAP) or a selective inhibitor of NO synthase (1400W) was injected intraperitoneally into the mice before the LPS stimulation. Decreased levels of proinflammatory cytokines were demonstrated in the bronchoalveolar lavage fluid from mice treated with SNAP, whereas increased levels of cytokines were found in the 1400W-treated mice. To further explore the molecular mechanism of NO-mediated inhibition of proinflammatory responses in macrophages, RAW 264.7 cells were treated with 1400W or SNAP before LPS stimulation. LPS-induced inflammation in the cells was attenuated by the presence of NO. The LPS-induced IκB kinase (IKK) activation and the expression of IKK were reduced by NO through attenuation of the interaction between Hsp90 and IKK in the cells. The IKK decrease in the lung immunohistopathology was verified in SNAP-treated asthma mice, whereas IKK increased in the 1400W-treated group. We report for the first time that NO attenuates the interaction between Hsp90 and IKK, decreasing the stability of IKK and causing the down-regulation of the proinflammatory response. Furthermore, the results suggest that NO may repress LPS-stimulated innate immunity to promote pulmonary bacterial infection in asthma patients.

Synthesis, characterization and catalytic activity of lithium and sodium iminophenoxide complexes towards ring-opening polymerization of L-lactide.

A series of lithium and sodium iminophenoxide complexes have been successfully synthesized and characterized by X-ray crystallography and investigated as catalysts for the ring opening polymerization of L-lactide. The nature and steric bulk of the ligands coordinated to the central metal ions greatly influence the catalytic properties. Complexes with bidenate ligands exhibit higher catalytic activity than tridentate counterparts because the third coordination atom contends with L-lactide, which decreases activity. Oxygen is the third atom in the tridentate ligand, providing stronger chelation ability with Li and Na than nitrogen or sulfur and occupies the space with which L-lactide is coordinated.