Evaluation of antioxidant and neuroprotective effect of date palm (Phoenix dactylifera L.) against bilateral common carotid artery occlusion in rats

The cerebral ischemia in rats was induced by occluding bilateral common carotid arteries (BCCAO) for 30 min., followed by 45 min reperfusion. BCCAO caused significant depletion in superoxide dismutase, catalase, glutathione, glutathione peroxidase, glutathione-S-transferase, glutathione reductase and significant increase in lipid peroxidation along with severe neuronal damage in the brain. All the alterations except depletion in glutathione peroxidase and glutathione-S-transferase levels induced by cerebral ischemia were significantly attenuated by 15 days pretreatment with methanolic extract of P. dactylifera fruits (100, 300 mg/kg), whereas 30 mg/kg dose was insignificant in this regard. These results suggest the possible use P. dactylifera against bilateral common carotid artery occlusion induced oxidative stress and neuronal damage.     

Ubiquitination regulates the assembly of VLDL in HepG2 cells and is the committing step of the apoB-100 ERAD pathway

Apolipoprotein B-100 (apoB-100) is degraded by endoplasmic reticulum-associated degradation (ERAD) when lipid availability limits assembly of VLDLs. The ubiquitin ligase gp78 and the AAA-ATPase p97 have been implicated in the proteasomal degradation of apoB-100. To study the relationship between ERAD and VLDL assembly, we used small interfering RNA (siRNA) to reduce gp78 expression in HepG2 cells. Reduction of gp78 decreased apoB-100 ubiquitination and cytosolic apoB-ubiquitin conjugates. Radiolabeling studies revealed that gp78 knockdown increased secretion of newly synthesized apoB-100 and, unexpectedly, enhanced VLDL assembly, as the shift in apoB-100 density in gp78-reduced cells was accompanied by increased triacylglycerol (TG) secretion. To explore the mechanisms by which gp78 reduction might enhance VLDL assembly, we compared the effects of gp78 knockdown with those of U0126, a mitogen-activated protein kinase/ERK kinase1/2 inhibitor that enhances apoB-100 secretion in HepG2 cells. U0126 treatment increased secretion of both apoB100 and TG and decreased the ubiquitination and cellular accumu-lation of apoB-100. Furthermore, p97 knockdown caused apoB-100 to accumulate in the cell, but if gp78 was concomitantly reduced or assembly was enhanced by U0126 treatment, cellular apoB-100 returned toward baseline. This indicates that ubiquitination commits apoB-100 to p97-mediated retrotranslocation during ERAD. Thus, decreasing ubiquitination of apoB-100 enhances VLDL assembly, whereas improving apoB-100 lipidation decreases its ubiquitination, suggesting that ubiquitination has a regulatory role in VLDL assembly.     

A transporter associated with antigen-processing independent vacuolar pathway for the MHC class I-mediated presentation of endogenous transmembrane proteins

MHC class I molecules present peptides derived from the ectodomains of endogenous transmembrane proteins; however, the processing of these Ags is incompletely understood. As model transmembrane Ags we investigated the processing of MHC-I-derived fusion proteins containing the N-terminally extended K(b)-restricted OVA epitope SIINFEKL in the extracytoplasmic domain. In TAP-deficient, nonprofessional APCs, the epitope was cleaved out of various sequence contexts and presented to T cells. Ag presentation was inhibited by acidophilic amines and inhibitors of the vacuolar proton pump, indicating processing in endosomes. Endosomal aspartic-type cathepsins, and to some extent also the trans-Golgi network protease furin, were involved in processing. Clathrin-dependent and independent internalization from the cell surface targeted MHC-I fusion proteins to early and late endosomes, where SIINFEKL/K(b) complexes were detected by immunofluorescence microscopy. Targeting of MHC-I fusion proteins to processing compartments was independent of sequence motifs in the cytoplasmic tail. Not only TAP-deficient cells, but also TAP-competent APCs used the vacuolar pathway for processing of MHC-I fusion proteins. Thus, endosomal processing of internalized endogenous transmembrane proteins represents a novel alternate pathway for the generation of MHC-I-binding peptides.     

Involvement of p38 Mapkinase in attenuation of antinociceptive effect of morphine in diabetic mice

Experimental diabetes induced by streptozotocin (200 mg/kg, ip) markedly decreased the antinociceptive effect of morphine and significantly increased the urinary nitrite concentration. Administration of FR-167653 (a selective p38MAPKinase inhibitor) in a dose of 4 mg/kg improved the antinociceptive effect of morphine and attenuated the increase in urinary nitrite concentration in diabetic mice. It may be concluded that diabetes-induced decrease in antinociceptive effect of morphine may be due to induction of p38 MAPKinase activity.     

Liposomes as adjuvant for combination vaccines

In the present study tetanus toxoid (TT) loaded liposomes and diphtheria toxoid (DT) loaded liposomes were prepared by reverse phase evaporation method and after combining these two vaccines the potential advantages were investigated. Prepared systems were characterized for the size, shape and entrapment efficiency. SDS-PAGE analysis of TT and DT was also performed. The selected liposomal formulations were administered subcutaneously to Balb/c mice and their immune responses were determined using ELISA after 15, 30, 45 days. After boosting the maximum immune response was observed after 45 days and was found to be 0.831 and 0.749 for TT loaded liposome and DT loaded liposomes respectively. When the mice were immunized subcutaneously with the physical mixture of TT loaded liposomes and DT loaded liposomes the immune response for the combination vaccine was found to be 1.44 and 0.741 for the TT and DT respectively. The result showed that the immune response of TT increased when it was combined with DT in liposomes. This confirms adjuvantcity of DT vis-a-vis immunogenicity. Thus, carrier mediated cocktail vaccination holds promise for clinical applications.     

A novel role of the lumican core protein in bacterial lipopolysaccharide-induced innate immune response

Lumican is an extracellular matrix protein modified as a proteoglycan in some tissues. The core protein with leucine-rich repeats, characteristic of the leucine-rich-repeat superfamily, binds collagen fibrils and regulates its structure. In addition, we believe that lumican sequestered in the pericellular matrix interacts with cell surface proteins for specific cellular functions. Here we show that bacterial lipopolysaccharide sensing by the Toll-like receptor 4 signaling pathway and innate immune response is regulated by lumican. Primary cultures of lumican-deficient (Lum(-/-)) macrophages show impaired innate immune response to lipopolysaccharides with lower induction of tumor necrosis factor alpha (TNFalpha) and interleukin-6. Macrophage response to other pathogen-associated molecular patterns is not adversely affected by lumican deficiency, suggesting a specific role for the lumican core protein in the Toll-like receptor 4 pathway. An exogenous recombinant lumican core protein increases lipopolysaccharide-mediated TNFalpha induction and partially rescues innate immune response in Lum(-/-) macrophages. We further show that the core protein binds lipopolysaccharide. Immunoprecipitation of lumican from peritoneal lavage co-precipitates CD14, a cell surface lipopolysaccharide-binding protein that is involved in its presentation to Toll-like receptor 4. The Lum(-/-) mice are hypo-responsive to lipopolysaccharide-induced septic shock, with poor induction of pro-inflammatory cytokines, TNFalpha, and interleukins 1beta and 6 in the serum. Taken together, the data indicates a novel role for lumican in the presentation of bacterial lipopolysaccharide to CD14 and host response to this bacterial endotoxin.     

Thyroid receptor ligands. Part 8: Thyromimetics derived from N-acylated-alpha-amino acid derivatives displaying modulated pharmacological selectivity compared with KB-141

Based on the scaffold of the pharmacologically selective thyromimetic 2b, structurally a close analog to KB-141 (2a), a number of novel N-acylated-alpha-amino acid derivatives were synthesized and tested in a TR radioligand binding assay as well as in a reporter cell assay. On the basis of TRbeta(1)-isoform selectivity and affinity, as well as affinity to the reporter cell assay, 3d was selected for further studies in the cholesterol-fed rat model. In this model 3d revealed an improved therapeutic window between cholesterol and TSH lowering but decreased margins versus tachycardia compared with 2a.     

Upregulation of Slc39a10 gene expression in response to thyroid hormones in intestine and kidney

A novel zinc transporter has been purified and cloned from rat renal brush border membrane. This transporter was designated as Zip10 encoded by Slc39a10 gene and characterized as zinc importer. Present study documents the impact of thyroid hormones on the expression of Zip10 encoded by Slc39a10 gene in rat model of hypo and hyperthyroidism. Serum T(3) and T(4) levels were reduced significantly in hypothyroid rats whereas these levels were significantly elevated in hyperthyroid rats as compared to euthyroid rats thereby confirming the validity of the model. Kinetic studies revealed a significant increase in the initial and equilibrium uptake of Zn(++) in both intestinal and renal BBMV of hyperthyroid rats in comparison to hypothyroid and euthyroid rats. By RT-PCR, Slc39a10 mRNA expression was found to be significantly decreased in hypothyroid and increased in hyperthyroid as compared to euthyroid rats. These findings are in conformity with the immunofluorescence studies that revealed markedly higher fluorescence intensity at periphery of both intestinal and renal cells isolated from hyperthyroid rats as compared to hypothyroid and euthyroid rats. Higher expression of Zip10 protein in hyperthyroid group was also confirmed by western blot. These findings suggest that expression of zinc transporter protein Zip10 (Slc39a10) in intestine and kidney is positively regulated by thyroid hormones.     

The genus Laggera (Asteraceae) – Ethnobotanical and Ethnopharmacological Information,Chemical Composition as well as Biological Activities of Its Essential Oils and Extracts: A Review

Most species of the genus Laggera are often used in traditional and folk medicines for the treatment of jaundice, inflammation, leukemia, removing phlegm, bronchitis and bacterial diseases. The essential oils obtained from Laggera plants are rich sources of oxygenated monoterpenes and sesquiterpenes. Among oxygenated monoterpenes, aromatic ether 2,5‐dimethoxy‐p‐cymene is the most abundant and dominant compound of many essential oils of the Laggera species. Till today, to the best of our knowledge, chemical compounds of the essential oils and/or extracts of only eight Laggera species were reported from different countries. Thus, this review presents the chemical compositions and biological activities of the essential oils of these plants studied in thirteen countries. In addition, it discusses the reported ethnobotanical and ethnopharmacological information as well as biological activities of the extracts and some of the isolated compounds of Laggera plants species.     

Maternal Magnesium Deficiency in Mice Leads to Maternal Metabolic Dysfunction and Altered Lipid Metabolism with Fetal Growth Restriction

Inadequate magnesium (Mg) intake is a widespread problem, with over 50% of women of reproductive age consuming less than the Recommended Dietary Allowance (RDA). Because pregnancy increases the requirement for Mg and the beneficial effects of magnesium sulfate for preeclampsia/eclampsia and fetal neuroprotection are well described, we examined the outcomes of Mg deficiency during pregnancy. Briefly, pregnant Swiss Webster mice were fed either control or Mg-deficient diets starting on gestational day (GD) 6 through euthanasia on GD17. Mg-deficient dams had significantly reduced weight gain and higher plasma adipokines, in the absence of inflammation. Livers of Mg-deficient dams had significantly higher saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs) and lower polyunsaturated fatty acids (PUFAs), including docosahexaenoic acid (DHA) (P < 0.0001) and arachidonic acid (AA) (P < 0.0001). Mechanistically, Mg deficiency was accompanied by enhanced desaturase and elongase mRNA expression in maternal livers along with higher circulating insulin and glucose concentrations (P < 0.05) and increased mRNA expression of Srebf1 and Chrebp, regulators of fatty acid synthesis (P < 0.05). Fetal pups exposed to Mg deficiency were growth-restricted and exhibited reduced survival. Mg-deficient fetal livers showed lower MUFAs and higher PUFAs, with lower desaturase and elongase mRNA expression than controls. In addition, DHA concentrations were lower in Mg-deficient fetal brains (P < 0.05). These results indicate that Mg deficiency during pregnancy influences both maternal and fetal fatty acid metabolism, fetal growth and fetal survival, and support better understanding maternal Mg status before and during pregnancy.