Disruption of the Golgi apparatus mediates zinc deficiency-induced impairment of cognitive function in mice.

Zinc deficiency is reported to be a global problem that affects cognitive function. The mechanism underlying zinc deficiency-induced impairment of cognitive function is still obscure. In this study, we treated KM mice (Kun Ming mice) with zinc chelator TPEN (N,N,N',N'-tetrakis(2-pyridinylmethyl)-1,2-ethanediamine) by i.p. injection. NOR (New Object Recognition) tests demonstrated that TPEN can impair the cognitive function of KM mice. Disruption of the GRASP55/Golgin45 complex, and even the Golgi apparatus, was also observed in hippocampus cells by TPEN treatment. Further investigation by IHF showed that enrichment of Aß peptides occurs in neurons of the cerebral tissue of mice, suggesting that amyloidosis may mediate TPEN-induced impairment of cognitive function. This research not only clarifies that zinc plays an important role in Golgi organization in vivo, but also gives us a possible novel pathway underlying AD development.

Substituted effect on some water-soluble Mn(II) salen complexes: DNA binding, cytotoxicity, molecular docking, DFT studies and theoretical IR & UV studies.

Based on the importance of central metal complexes to interact with DNA, in this research focused on synthesis of some new water soluble Mn(II) complexes 1-4 which modified substituted in ligand at the same position with N, Me, H, and Cl. These complexes were isolated and characterized by elemental analyses, FT-IR, electrospray ionization mass spectrometry (ESI-MS) and UV-vis spectroscopy. DNA binding studies had been studied by using circular dichroism (CD) spectroscopy, UV-vis absorption spectroscopy, cyclic voltammetry (CV), viscosity measurements, emission spectroscopy and gel electrophoresis which proposed the metal buildings go about as effective DNA binders were studied in the presence of Fish-DNA (FS-DNA) which showed the highest binding affinity to DNA with hydrophobic and electron donating substituent. Cell toxicity assays against two human leukemia (Jurkat) and breast cancer (MCF-7) cell lines showed that the complex 3 exhibited a remarkable effects equal to a famous anticancer drug, cisplatin that high cytotoxic activity strongly depend on the hydrophobic substituted ligand. In the theoretical part, density functional theory (DFT) was performed to optimize the geometry of complexes through IR and UV spectra of the complexes that ligand substitution did not affect the geometry and theoretical IR and UV spectra showed good resemblance to the experimental data. The docking studies calculated the lowest-energy between complexes and DNA with the minor grooves mode.

DNA methylation mechanism of intracellular zinc deficiency-induced injury in primary hippocampal neurons in the rat brain.

OBJECTIVE: To explore Zn2+ deficiency-induced neuronal injury in relation to DNA methylation, providing valuable data and basic information for clarifying the mechanism of Zn2+ deficiency-induced neuronal injury. METHODS: Cultured hippocampal neurons were exposed to the cell membrane-permeant Zn2+ chelator N,N,N',N'-Tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) (2 µM), and to TPEN (2 µM) plus ZnSO4 (5 µM) for 24 hours. We analyzed intracellular Zn2+ levels, neuronal viability, and protein/mRNA levels for DNA (cytosine-5) methyltransferase 1 (DNMT1), DNA (cytosine-5-) methyltransferase 3 alpha (DNMT3a), methyl CpG binding protein 2 (MeCP2), Brain-derived neurotrophic factor (BDNF), and growth arrest and DNA-damage-inducible, beta (GADD45b) in the treated neurons. RESULTS: We found that exposure of hippocampal neurons to TPEN (2 µM) for 24 hours significantly reduced intracellular Zn2+ concentration and neuronal viability. Furthermore, DNMT3a, DNMT1, BDNF, and GADD45b protein levels in TPEN-treated neurons were significantly downregulated, whereas MeCP2 levels were, as expected, upregulated. In addition, DNMT3a and DNMT1 mRNA levels in TPEN-treated neurons were downregulated, while MeCP2, GADD45b, and BDNF mRNA were largely upregulated. Addition of ZnSO4 (5 µM) almost completely reversed the TPEN-induced alterations. CONCLUSION: Our data suggest that free Zn2+ deficiency-induced hippocampal neuronal injury correlates with free Zn2+ deficiency-induced changes in methylation-related protein gene expression including DNMT3a/DNMT1/MeCP2 and GADD45b, as well as BDNF gene expression.

The iron chelating agent, deferoxamine detoxifies Fe(Salen)-induced cytotoxicity.

Iron-salen, i.e., µ-oxo-N,N'-bis(salicylidene)ethylenediamine iron (Fe(Salen)) was a recently identified as a new anti-cancer compound with intrinsic magnetic properties. Chelation therapy has been widely used in management of metallic poisoning, because an administration of agents that bind metals can prevent potential lethal effects of particular metal. In this study, we confirmed the therapeutic effect of deferoxamine mesylate (DFO) chelation against Fe(Salen) as part of the chelator antidote efficacy. DFO administration resulted in reduced cytotoxicity and ROS generation by Fe(Salen) in cancer cells. DFO (25 mg/kg) reduced the onset of Fe(Salen) (25 mg/kg)-induced acute liver and renal dysfunction. DFO (300 mg/kg) improves survival rate after systematic injection of a fatal dose of Fe(Salen) (200 mg/kg) in mice. DFO enables the use of higher Fe(Salen) doses to treat progressive states of cancer, and it also appears to decrease the acute side effects of Fe(Salen). This makes DFO a potential antidote candidate for Fe(Salen)-based cancer treatments, and this novel strategy could be widely used in minimally-invasive clinical settings.

Zinc Depletion by TPEN Induces Apoptosis in Human Acute Promyelocytic NB4 Cells.

BACKGROUND/AIMS: The effects of zinc signaling on proliferation or apoptosis of leukemia cells remain elusive. In the present study, we used N, N, N', N'-tetrakis-(2-pyridylmethyl)-ethylene-diamine (TPEN), a membrane-permeable zinc chelator, to evaluate the effect of zinc depletion on survival and apoptosis of NB4 acute promyelocytic leukemia (APL) cells. METHODS: The pro-apoptotic effects of TPEN on NB4 cells were examined by flow cytometry, and observed using an optical microscope. Intracellular labile zinc, nitric oxide (NO) or reactive oxygen species (ROS) changes caused by TPEN were measured by flow cytometry. We then explored possible roles of the crosstalk between intracellular labile zinc signaling and nitric oxide signaling in TPEN-triggered apoptosis. RESULTS: we found that TPEN induced apoptosis in NB4 APL cells in a dosage-dependent manner. We further demonstrated that TPEN triggered apoptosis by attenuating intracellular zinc and nitric oxide signaling in NB4 cells. Both exogenous zinc supplement and the nitric donor sodium nitroprusside (SNP) pre-incubation reversed TPEN-mediated inhibition of intracellular NO and Zn2+ signaling, and rescued NB4 cells from apoptosis. CONCLUSION: These results suggest for the first time that crosstalk between zinc signaling and nitric oxide pathway is essential for the survival of NB4 cells. TPEN induces apoptosis in NB4 cells via negatively regulating intracellular NO and Zn2+ signaling. Our in vitro data suggest that zinc depletion by TPEN may be a potential therapeutic strategy for APL.

Comparison of toxicity and teratogenic effects of salen and vo-salen on chicken embryo.

OBJECTIVES: The toxic and teratogenic effects of salen (C16H16N2O2) and salen vanadium oxide (VOS) (C16H14N2O3V) were evaluated against chicken embryos along with chicken hepatic and fibroblastic cells in vitro cultures. METHODS: Salen and VOS complexes were injected in the following concentrations: 5, 10, 20, 40, 80, 160, and 300 µM/egg for salen and 7.5, 15, 75, 120, 150, 240, and 300 µM/egg for VOS. In order to screen for skeletal malformations, the alizarin red clearing and staining method was employed. For studying the cytotoxic effects of these compounds, hepatic and fibroblastic cells were cultured and treated. RESULTS: Our results show that injecting salen with various concentrations leads to a significant increase in embryonic mortality. Skeletal and morphological malformations resulting from salen injections included ectopic viscera and club foot. Our results show that embryonic mortality increased relative to the control group. In addition, alizarin red staining showed skeletal malformations like deletion of caudal vertebrae. DISCUSSION: Our comparison showed that salen was a stronger teratogen than VOS, which may be due roles of the vanadium element, whose derivatives show physiological particulars and at low concentrations plays anticancer specifications without toxic effect. CONCLUSION: Results show that chicken embryos were sensitive to the toxicity of salen and VOS, and these compounds can affect the growth and ossification of the chicken embryos. Moreover, the cytotoxicity of salen and VOS shows that the viability of both salen and VOS-treated cells significantly decreased in a dose-dependent manner.

Naphthoquinone derivative PPE8 induces endoplasmic reticulum stress in p53 null H1299 cells.

Endoplasmic reticulum (ER) plays a key role in synthesizing secretory proteins and sensing signal function in eukaryotic cells. Responding to calcium disturbance, oxidation state change, or pharmacological agents, ER transmembrane protein, inositol-regulating enzyme 1 (IRE1), senses the stress and triggers downstream signals. Glucose-regulated protein 78 (GRP78) dissociates from IRE1 to assist protein folding and guard against cell death. In prolonged ER stress, IRE1 recruits and activates apoptosis signal-regulating kinase 1 (ASK1) as well as downstream JNK for cell death. Naphthoquinones are widespread natural phenolic compounds. Vitamin K3, a derivative of naphthoquinone, inhibits variant tumor cell growth via oxygen uptake and oxygen stress. We synthesized a novel naphthoquinone derivative PPE8 and evaluated capacity to induce ER stress in p53 null H1299 and p53 wild-type A549 cells. In H1299 cells, PPE8 induced ER enlargement, GRP78 expression, and transient IER1 activation. Activated IRE1 recruited ASK1 for downstream JNK phosphorylation. IRE1 knockdown by siRNA attenuated PPE8-induced JNK phosphorylation and cytotoxicity. Prolonged JNK phosphorylation may be involved in PPE8-induced cytotoxicity. Such results did not arise in A549 cells, but p53 knockdown by siRNA restored PPE8-induced GRP78 expression and JNK phosphorylation. We offer a novel compound to induce ER stress and cytotoxicity in p53-deficient cancer cells, presenting an opportunity for treatment.

Zinc preconditioning protects against neuronal apoptosis through the mitogen-activated protein kinase-mediated induction of heat shock protein 70.

During brain ischemic preconditioning (PC), mild bursts of ischemia render neurons resistant to subsequent strong ischemic injuries. Previously, we reported that zinc plays a key role in PC-induced neuroprotection in vitro and in vivo. Zinc-triggered p75(NTR) induction transiently activates caspase-3, which cleaves poly(ADP-ribose) polymerase-1 (PARP-1). Subsequently, the PARP-1 over-activation-induced depletion of nicotinamide adenine dinucleotide (NAD(+))/adenosine triphosphate (ATP) after exposures to lethal doses of zinc or N-methyl-D-aspartate is significantly attenuated in cortical neuronal cultures. In the present study, zinc-mediated preconditioning (Zn PC) reduced apoptotic neuronal death that was caused by N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), etoposide, or staurosporine in mouse cortical cells. We focused on heat shock protein 70 (HSP70) because NAD(+)/ATP depletion does not directly cause apoptosis, and HSP70 can inhibit the activation of caspase-9 or caspase-3 by preventing apoptosome formation or cytochrome C release. Zn PC-mediated HSP70 induction was required for neuroprotection against neuronal apoptosis, and geldanamycin-induced HSP70 induction sufficiently blocked neuronal apoptotic cell death. Furthermore, Zn PC-mediated HSP70 induction was blocked by chemical inhibitors of extracellular signal-regulated kinase (ERK) or p38 mitogen-activated protein kinase (MAPK) signaling, but not c-Jun N-terminal protein kinase. Similarly, neuroprotection by Zn PC against TPEN-induced apoptosis was almost completely reversed by the blockade of ERK or p38 MAPK signaling. Our findings suggest that the ERK- or p38 MAPK-mediated induction of HSP70 plays a key role in inhibiting caspase-3 activation during Zn PC.

Cytotoxic activity of N, N'-Bis (2-hydroxybenzyl) ethylenediamine derivatives in human cancer cell lines.

BACKGROUND: Compounds containing ethylenediamine (-NCH2CH2N-) moiety are known to exhibit antimicrobial, -fungal, -bacterial, -tuberculosis and -cancer activities. MATERIALS AND METHODS: In the present study, we evaluated the in vitro cytotoxic activity of N,N'-bis(2-hydroxybenzyl)- (6), N,N'-bis(5-bromo-2-hydroxybenzyl)- (7) and N,N'-bis(5-chloro-2-hydroxybenzyl) (8)- ethylenediamine dihydrochlorides; and N,N'-bis(2-hydroxybenzyl)- (9), N,N'-bis(5-bromo-2-hydroxybenzyl)- (10) and N,N'-bis(5-chloro-2-hydroxybenzyl) (11)- ethylenediamine toward human lung (A549), breast (MDA-MB-231) and prostate (PC3) cancer cell lines after 24-h treatment using crystal violet dye binding assay. Effects on the cell cycle the using flow cytometry, and mitochondrial membrane potential using rhodamine-123 florescent dye were also evaluated. RESULTS: Compounds 7 and 8 exhibit cytotoxic activity, causing cell arrest at different phases of the cell cycle and loss of mitochondrial membrane potential in the above cancer cell lines. CONCLUSION: These findings clearly demonstrate, to our knowledge for the first time, that ethylenediamine dihydrochloride salts-compounds 7 and 8-exhibit concentration-dependent cytotoxic activity towards A549, MDA-MB-231 and PC3 cancer cell lines, which may serve as a basis for future work on novel therapeutic agents.

Synthesis and initial in vitro biological evaluation of two new zinc-chelating compounds: comparison with TPEN and PAC-1.

The lipophilic, cell-penetrating zinc chelator N,N,N',N',-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN, 1) and the zinc chelating procaspase-activating compound PAC-1 (2) both have been reported to induce apoptosis in various cell types. The relationship between apoptosis-inducing ability and zinc affinity (Kd), have been investigated with two new model compounds, ZnA-DPA (3) and ZnA-Pyr (4), and compared to that of TPEN and PAC-1. The zinc-chelating o-hydroxybenzylidene moiety in PAC-1 was replaced with a 2,2'-dipicoylamine (DPA) unit (ZnA-DPA, 3) and a 4-pyridoxyl unit (ZnA-Pyr, 4), rendering an order of zinc affinity TPEN>ZnA-Pyr>ZnA-DPA>PAC-1. The compounds were incubated with the rat pheochromocytoma cell line PC12 and cell death was measured in combination with ZnSO4, a caspase-3 inhibitor, or a ROS scavenger. The model compounds ZnA-DPA (3) and ZnA-Pyr (4) induced cell death at higher concentrations as compared to PAC-1 and TPEN, reflecting differences in lipophilicity and thereby cell-penetrating ability. Addition of ZnSO4 reduced cell death induced by ZnA-Pyr (4) more than for ZnA-DPA (3). The ability to induce cell death could be reversed for all compounds using a caspase-3-inhibitor, and most so for TPEN (1) and ZnA-Pyr (4). Reactive oxygen species (ROS), as monitored using dihydro-rhodamine (DHR), were involved in cell death induced by all compounds. These results indicate that the Zn-chelators ZnA-DPA (3) and ZnA-Pyr (4) exercise their apoptosis-inducing effect by mechanisms similar to TPEN (1) and PAC-1 (2), by chelation of zinc, caspase-3 activation, and ROS production.

Therapeutic efficacy of 188Re-liposome in a C26 murine colon carcinoma solid tumor model.

Nanoliposomes are good drug delivery systems that allow the encapsulation of drugs into vesicles for their delivery. The objective of this study is to investigate the therapeutic efficacy of a new radio-therapeutics of (188)Re-labeled pegylated liposome in a C26 murine colon carcinoma solid tumor model. The safety of (188)Re-liposome was evaluated before radiotherapy treatment. The anti-tumor effect of (188)Re-liposome was assessed by tumor growth inhibition, survival ratio and ultrasound imaging. Apoptotic marker in tumor was also evaluated by the TUNEL (terminal deoxynucleotidyl transferase biotin-dUTP nick-end labeling) method after injection of (188)Re-liposome. The group treated with (188)Re-liposome displayed slight loss in body weight and decrease in white blood cell (WBC) count 7 to 14 days post-injection. With respect to therapeutic efficacy, the tumor-bearing mice treated with (188)Re-liposome showed better mean tumor growth inhibition rate (MGI) and longer median survival time (MGI = 0.140; 80 day) than those treated with anti-cancer drug 5-FU (MGI = 0.195; 69 day) and untreated control mice (MGI = 0.413; 48 day). The ultrasound imaging showed a decrease in both tumor volume and number of blood vessels. There were significantly more apoptotic nuclei (TUNEL-positive) in (188)Re-liposome-treated mice at 8 h after treatment than in control mice. These results evidenced the potential benefits achieved by oncological application of the radio-therapeutics (188)Re-liposome for adjuvant cancer treatment.

The influence of EDDS on the metabolic and transcriptional responses induced by copper in hydroponically grown Brassica carinata seedlings.

To improve the knowledge about the use of plants for the removal of toxic metals from contaminated soils, metabolic and transcriptional responses of Brassica carinata to different forms of copper (Cu) were studied. Two-week-old hydroponically grown seedlings were exposed for 24 h to 30 µM CuSO4 or CuEDDS. CuSO4 appeared to be more toxic than CuEDDS as roots showed higher levels of thiobarbituric acid reactive substances (TBARS) and increased relative leakage ratios (RLR), although the superoxide dismutase (SOD, EC 1.15.1.1) activity increased following both exposures. In CuSO4-exposed seedlings the higher toxicity was underlined by increased transcription of lipoxygenases (EC 1.13.11.12) and NADPH oxidases (EC 1.6.99.6) and by the higher Cu accumulation in both tissues compared to CuEDDS exposure. The presence of EDDS increased Cu translocation, which resulted 5-times higher than when exposed to CuSO4. Decreases in catalase (CAT, EC 1.11.1.6), ascorbate peroxidase (APX, EC 1.11.1.11) and glutathione reductase (GR, EC 1.6.4.2) activities together with increases of reduced glutathione (GSH) and tocopherols and a reduction of lipoic acid (LA) were observed in roots of CuSO4-exposed seedlings. On the contrary, CuEDDS exposure induced a general increase in enzyme activities and decreases in ascorbate (AsA) and tocopherol levels. In the primary leaves, in both exposures Cu differently affected the oxidative stress responses indicating that the cellular redox balance was anyway maintained. EDDS plays a crucial role in B. carinata tolerance to oxidative stress induced by Cu and might be proposed to improve the efficiency of Cu phytoextraction.

Acute intravenous injection toxicity of BMEDA in mice.

(188)Re/(186)Re-N,N-bis(2-mercaptoethyl)-N',N'-diethylethylenediamine-labeled pegylated liposome ((188)Re-BMEDA-liposome) has been proven as a promising candidate for cancer therapy in tumor-rodent models. (188)Re-BMEDA complexes should be prepared for the radiolabeling of liposomes. This article describes the acute toxicity of BMEDA in Imprinting Control Region (ICR) mice. Treated mice were administered with BMEDA at dose levels of 3, 6, 9, and 12 mg/kg, with a dose volume of 10 mL/kg. The control mice were administered 10 mL/kg of vehicle control. The mice were observed for 14 days. Observations included mortality, clinical signs, total body-weight gains, food consumption, and gross necropsy findings. BMEDA exerted no adverse toxic effects in ICR mice at dose levels 3 mg/kg, which are up to 360,000 times higher than the intended human dose. The lethal-dose (LD(50)) value of BMEDA was 8.13 and 8.68 mg/kg in male and female mice, respectively.

N-alkylation of poloxamines modulates micellar assembly and encapsulation and release of the antiretroviral efavirenz.

Poloxamines (X-shaped poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO) diblocks connected to a central ethylenediamine group) were N-methylated and N-allylated with the aim of widening their versatility as drug nanocarriers. The self-aggregation properties of various derivatives, covering a wide range of molecular weights and EO/PO ratios, were thoroughly investigated. The cytocompatibility of different modified poloxamines was compared to that of the pristine counterparts by MTT and LDH assays. The most hydrophilic varieties were highly cytocompatible even at concentrations of 5%. Toward the optimization of the oral pharmacotherapy of the Human Immunodeficiency Virus (HIV) infection in pediatric patients, the encapsulation and in vitro delivery of efavirenz (EFV), a lipophilic first-line antiretroviral drug, were evaluated. Pristine and N-alkylated poloxamines behaved as highly efficient EFV solubilizers enhancing the aqueous solubility of the drug between 166 and 7426-times. EFV promotes self-micellization of poloxamines; their tiny structural modification (i.e., just one methyl- or allyl-group) being able to regulate drug/micellar core interaction. Despite the physical stability of the micelles against dilution in physiological mimicking fluids, the N-alkylated derivatives were slightly more prone to disassembly promoting EFV release from the micellar reservoir. For all the derivatives evaluated, the in vitro release fitted zero-order kinetics and was sustained for at least 24 h. These findings point out N-alkylated poloxamines as promising nanocarriers for oral or parenteral drug delivery.

Glycosylated tetrahydrosalens as multifunctional molecules for Alzheimer's therapy.

The tetrahydrosalens N,N'-bis(2-hydroxybenzyl)-ethane-1,2-diamine ((2)(1)), N,N'-bis(2-hydroxybenzyl)-(-)-1,2-cyclohexane-(1R,2R)-diamine ((2)(2)), N,N'-bis(2-hydroxybenzyl)-N,N'-dimethyl-ethane-1,2-diamine ((2)(3)), N,N'-bis(2-hydroxybenzyl)-N,N'-dibenzyl-ethane-1,2-diamine ((2)(4)), and N,N'-bis(2-(4-tert-butyl)hydroxybenzyl)-ethane-1,2-diamine ((2)(5)), as well as their prodrug glycosylated forms, (1-5), have been prepared and evaluated in vitro for their potential use as Alzheimer's disease (AD) therapeutics. Dysfunctional interactions of metal ions, especially those of Cu, Zn, and Fe, with the amyloid-beta (Abeta) peptide are hypothesised to play an important role in the aetiology of AD, and disruption of these aberrant metal-peptide interactions via chelation therapy holds considerable promise as a therapeutic strategy. Tetrahydrosalens such as (2)(1-5) have a significant affinity for metal ions, and thus should be able to compete with the Abeta peptide for Cu, Zn, and Fe in the brain. This activity was assayed in vitrovia a turbidity assay; (2)(1) and (2)(3) were found to attenuate Abeta(1-40) aggregation after exposure to Cu(2+) and Zn(2+). In addition, (2)(1-5) were determined to be potent antioxidants on the basis of an in vitro antioxidant assay. (1-5) were prepared as metal binding prodrugs; glycosylation is intended to prevent systemic metal binding, improve solubility, and enhance brain uptake. Enzymatic (beta-glucosidase) deprotection of the carbohydrate moieties was facile, with the exception of (4), demonstrating the general feasibility of this prodrug approach. Finally, a representative prodrug, (3), was determined to be non-toxic over a large concentration range in a cell viability assay.

Polyhydroxylalkyleneamines: a class of hydrophilic cationic polymer-based gene transfer agents.

A new series of cationic polymers, poly[N,N-bis-(2-hydroxylpropyl) alkylalcoholamine-co-ethylenediamine] were synthesized by directly cross-linking several dichloro alkylating agents with ethylenediamine and its derivatives. Co-polymerization with cystamine introduces biodegradable disulfide bonds to the polymer backbone. When tested on COS-1 cells, PHAs showed reduced cytotoxicity, broad polymer to DNA ratios, and enhanced transfection activity that was 2-9-fold better than that of polyethylenimine. Comparison studies also revealed several chemical and physical parameters related to the biological activities of these polymers. The length of the side chain groups affects both transfection activity and toxicity of the polymers; a side chain group of moderate size appeared to be optimal for both high transfection activity and low toxicity. Introduction of biodegradable disulfide bonds to the polymer backbone further enhanced transfection activity and reduced toxicity of the polymer. Fractionated PHAs with molecular weight of > or =5000 Da were equally effective but smaller polymers were ineffective in transfection. This flexible synthesis route enables the determination of key structural and physical parameters related to polymer activity and could aid further improvement of polymer-based transfection agents.

A multifunctional and reversibly polymerizable carrier for efficient siRNA delivery.

In this study a multifunctional carrier (MFC), 1,4,7-triazanonylimino-bis[N-(oleicyl-cysteinyl-histinyl)-1-aminoethyl)propionamide] (THCO), containing protonatable amines of different pK(a)s, polymerizable cysteine residues and hydrophobic groups, was designed, synthesized and evaluated for efficient small interfering RNAs (siRNA) delivery. THCO showed pH-sensitive cellular membrane disruption at the endosomal-lysosomal pH to facilitate intracellular siRNA delivery. THCO formed stable and compact nanoparticles with siRNA through charge complexation, hydrophobic condensation and reversible polymerization. The THCO/siRNA nanoparticles were readily modified with PEG-Mal by reacting with remaining thiol groups at the surface. The siRNA delivery efficiency of THCO was comparable to that of Transfast, much higher than that of N-(2,3-dioleoyloxy-1-propyl)trimethylammonium methyl sulphate (DOTAP) in serum-free medium. PEGylated THCO/siRNA nanoparticles resulted in higher transfection efficiency than those of Transfast and DOTAP in the presence of serum. This study demonstrated that the MFC-THCO is promising for efficient siRNA delivery.

Postanoxic damage of microglial cells is mediated by xanthine oxidase and cyclooxygenase.

Brain ischemia and the following reperfusion are important causes for brain damage and leading causes of brain morbidity and human mortality. Numerous observations exist describing the neuronal damage during ischemia/reperfusion, but the outcome of such conditions towards glial cells still remains to be elucidated. Microglia are resident macrophages in the brain. In this study, we investigated the anoxia/reoxygenation caused damage to a microglial cell line via determination of energy metabolism, free radical production by dichlorofluorescein fluorescence and nitric oxide production by Griess reagent. Consequences of oxidant production were determined by measurements of protein oxidation and lipid peroxidation, as well. By using site-specific antioxidants and inhibitors of various oxidant-producing pathways, we identified major sources of free radical production in the postanoxic microglial cells. The protective influences of these compounds were tested by measurements of cell viability and apoptosis. Although, numerous free radical generating systems may contribute to the postanoxic microglial cell damage, the xanthine oxidase- and the cyclooxygenase-mediated oxidant production seems to be of major importance.

The influence of EDDS and EDTA on the uptake of heavy metals of Cd and Cu from soil with tobacco Nicotiana tabacum.

Phytoextraction, the use of plants to extract contaminants from soils and groundwater, is a promising approach for cleaning up soils contaminated with heavy metals. In order to enhance phytoextraction the use of chelating agents has been proposed. This study aims to assess whether ethylene diamine disuccinate (EDDS), a biodegradable chelator, can be used for enhanced phytoextraction purposed, as an alternative to ethylene diamine tetraacetate (EDTA). EDDS revealed a higher toxicity to tobacco (Nicotiana tabacum) in comparison to EDTA, but no toxicity to microorganisms. The uptake of Cu was increased by the addition of EDTA and EDDS, while no increase was observed in the uptake of Cd. Both chelating agents showed a very low root to shoot translocation capability and the translocation factor was lower than the one of the control. Heavy metals where significantly more phytoavailable than in the control, even after harvesting, resulting in a high heavy metal leaching possibility, probably owing to a low biodegradation rate of EDDS. New seedlings which were transplanted into the EDDS treated pots 7d after the phytoextraction experiment, showed signs of necrosis and chlorosis, which resulted in a significantly lower biomass in comparison to the control. The seedlings on the EDTA treated pots showed no toxicity signs. Contrary to previous opinions the results of this study revealed the chelating agents EDTA and EDDS as unsuitable for enhanced phytoextraction using tobacco.