Size and time-dependent induction of proinflammatory cytokines expression in brains of mice treated with gold nanoparticles

Gold nanoparticles (GNPs) are among the ideal nano-sized materials for medical applications such as imaging and drug delivery. Considering the significance of recent reports on acute phase induction of inflammatory mediators by GNPs, we studied the effect of GNPs on proinflammatory cytokines gene expression in mouse brain. Group 1 served as control whereas groups 2–4 were given only one intraperitoneal dose of 5, 20 and 50?nm GNPs, respectively and sacrificed after 24?h. The animals in groups 5–7 also received the same treatment but sacrificed after 7?days. Groups 8–10 received two injections of GNPs (5, 20 and 50?nm, respectively), first at the beginning of study and second on day 6, and sacrificed on day 7. Total RNA was extracted from the cerebral tissue and analyzed for the gene expressions of IL-1β, IL-6 and TNF-α. A single injection of 5?nm diameter GNPs significantly increased the mRNA expression of IL-1β and IL-6 in mouse brain on day 7, which was not augmented by the second dose of the same GNPs. Larger size GNPs (20?nm and 50?nm) did not cause any significant change in the expression of proinflammatory cytokines in mouse brain. In conclusion, systemic administration of small sized GNPs (5?nm) induced a proinflammatory cascade in mouse brain indicating a crucial role of GNPs size on immune response. It is important to use the right sized GNPs in order to avoid an acute phase inflammatory response that could be cytotoxic or interfere with the bioavailability of nanomaterials.     

Insulin-like growth factor type-1 receptor transactivation in vasoactive peptide and oxidant-induced signaling pathways in vascular smooth muscle cells

Transactivation of epidermal growth factor receptor (EGFR) is a well-documented mechanism by which vasoactive peptides and H2O2 elicit their cellular responses. However, a role for the insulin-like growth factor type-1 receptor (IGF-1R) transactivation in mediating the effects of angiotensin II (Ang II) and H2O2 in vascular smooth muscle cells from different artery types have also been recently recognized. By using a series of pharmacological inhibitors of various growth factor receptor tyrosine kinases and a direct analysis of the phosphorylation status of the beta-subunit of IGF-1R, a requirement of this growth factor receptor in Ang II and H2O2 response has been demonstrated. This review discusses some of the studies that highlight the importance of IGF-1R transactivation in mediating Ang II- and H2O2-induced mitogen-activated protein kinase and protein kinase B signaling pathways.     

Measurement of cell proliferation by heavy water labeling

DNA replication occurs almost exclusively during S-phase of the cell cycle and represents a simple biochemical metric of cell division. Previous methods for measuring cell proliferation rates have important limitations. Here, we describe experimental protocols for measuring cell proliferation and death rates based on the incorporation of deuterium ((2)H) from heavy water ((2)H(2)O) into the deoxyribose moiety of purine deoxyribonucleotides in DNA of dividing cells. Label incorporation is measured by gas chromatography/mass spectrometry. Modifications of the basic protocol permit analysis of small cell samples (down to 2,000 cells). The theoretical basis and operational requirements for effective use of these methods to measure proliferation and death rates of cells in vivo are described. These methods are safe for use in humans, have technical and interpretation advantages over alternative techniques and can be used on small numbers of cells. The protocols enable definitive in vivo studies of the fraction or absolute number of newly divided cells and their subsequent survival kinetics in animals and humans.     

Effects of the isothiocyanate sulforaphane on TGF-β1-induced rat cardiac fibroblast activation and extracellular matrix interactions

An important step in many pathological conditions, particularly tissue and organ fibrosis, is the conversion of relatively quiescent cells into active myofibroblasts. These are highly specialized cells that participate in normal wound healing but also contribute to pathogenesis. These cells possess characteristics of smooth muscle cells and fibroblasts, have enhanced synthetic activity secreting abundant extracellular matrix components, cytokines, and growth factors, and are capable of generating contractile force. As such, these cells have become potential therapeutic targets in a number of disease settings. Transforming growth factor β (TGF-β) is a potent stimulus of fibrosis and myofibroblast formation and likewise is an important therapeutic target in several disease conditions. The plant-derived isothiocyanate sulforaphane has been shown to have protective effects in several pathological models including diabetic cardiomyopathy, carcinogenesis, and fibrosis. These studies suggest that sulforaphane may be an attractive preventive agent against disease progression, particularly in conditions involving alterations of the extracellular matrix and activation of myofibroblasts. However, few studies have evaluated the effects of sulforaphane on cardiac fibroblast activation and their interactions with the extracellular matrix. The present studies were carried out to determine the potential effects of sulforaphane on the conversion of quiescent cardiac fibroblasts to an activated myofibroblast phenotype and associated alterations in signaling, expression of extracellular matrix receptors, and cellular physiology following stimulation with TGF-β1. These studies demonstrate that sulforaphane attenuates TGF-β1-induced myofibroblast formation and contractile activity. Sulforaphane also reduces expression of collagen-binding integrins and inhibits canonical and noncanonical TGF-β signaling pathways.     

The antileukemic effects of saffron (Crocus sativus L.) and its related molecular targets: A mini review

Saffron (Crocus sativus L.), and its main constituents, crocin, and crocetin have shown promising effects as an antileukemic agent in animal models and cell culture systems. Saffron retards the growth of cancer cells via inhibiting nucleic acid synthesis and enhancing antioxidative system. It can induce apoptosis and chemosensitivity via inhibiting multidrug resistance proteins. Saffron also induces differentiation pathways via inhibiting promyelocytic leukemia/retinoic acid receptor-α, histone deacetylase1, and tyrosyl DNA phosphodiesterase-1 as well. The present review highlights the most recent findings on the antileukemic effects of saffron and its underlying molecular targets. The emerging evidence suggests that saffron has a selective toxicity effect against leukemic cells while is safe for the normal cells.     

Differential expression of human basic fibroblast growth factor in Escherichia coli: potential role of promoter

Four different expression systems were developed for expression of the cDNA encoding human basic fibroblast growth factor (hbFGF), using Escherichia coli as host organism. The hbfgf structural gene was cloned into four expression vectors, pET-3a, pTrc99A, pPR37 and pKK223-3 differing only in their promoters, which were T7, trc, PR and tac respectively. Expression of the gene was induced by adding 0.5 mM (final concentration) of isopropyl--D-thio-galactopyranoside (IPTG) for the vectors carrying T7, trc and tac promoters or by a temperature shift from 30 to 42 °C for the vector carrying PR. The highest level of expression was observed in pET-1005 (a pET-3a derivative)/BL21 (DE3) system with 18.5 mg/l rhbFGF and the second high level expression was in pR37-1007 (pPR37 derivative) BL21 (DE3) system with 5 mg of rhbFGF/l. Since in the latter system a temperature shift was used for induction, 29% of the hbFGF was recovered as inclusion bodies in the insoluble cell fraction. The level of expression for the two other systems (pTrc-1006 and pKK-1008) was very low.     

Microtubules of guard cells are light sensitive

Guard cells of stomata are characterized by ordered bundles of microtubules radiating from the ventral side toward the dorsal side of the cylindrical cell. It was suggested that microtubules play a role in directing the radial arrangement of the cellulose micro-fibrils of guard cells. However, the role of microtubules in daily cycles of opening and closing of stomata is not clear. The organization of microtubules in guard cells of Commelina communis leaves was studied by analysis of three-dimensional immunofluorescent images. It was found that while guard cell microtubules in the epidermis of leaves incubated in the light were organized in parallel, straight and dense bundles, in the dark they were less straight and oriented randomly near the stomatal pore. The effect of blue and red light on the organization of guard cell microtubules resembled the effects of white light and dark respectively. When stomata were induced to open in the dark with fusicoccin, microtubules remained in the dark configuration. Furthermore, when incubated in the light, guard cell microtubules were more resistant to oryzalin. Similarly, microtubules of Arabidopsis guard cells, expressing green fluorescent protein-tubulin alpha 6, were disorganized in the dark, but were organized in parallel arrays in the presence of white light. The dynamics of microtubule rearrangement upon transfer of intact leaves from dark to light was followed in single stomata, showing that an arrangement of microtubules typical for light conditions was obtained after 1 h in the light. Our data suggest that microtubule organization in guard cells is responsive to light signals.