Marie Goua

Aerobic interval exercise improves parameters of nonalcoholic fatty liver disease (NAFLD) and other alterations of metabolic syndrome in obese Zucker rats

Metabolic syndrome (MS) is a group of metabolic alterations that increase the susceptibility to cardiovascular disease and type 2 diabetes. Nonalcoholic fatty liver disease has been described as the liver manifestation of MS. We aimed to test the beneficial effects of an aerobic interval training (AIT) protocol on different biochemical, microscopic, and functional liver alterations related to the MS in the experimental model of obese Zucker rat. Two groups of lean and obese animals (6 weeks old) followed a protocol of AIT (4 min at 65%-80% of maximal oxygen uptake, followed by 3 min at 50%-65% of maximal oxygen uptake for 45-60 min, 5 days/week, 8 weeks of experimental period), whereas 2 control groups remained sedentary. Obese rats had higher food intake and body weight (P < 0.0001) and suffered significant alterations in plasma lipid profile, area under the curve after oral glucose overload (P < 0.0001), liver histology and functionality, and antioxidant status. The AIT protocol reduced the severity of alterations related to glucose and lipid metabolism and increased the liver protein expression of PPARγ, as well as the gene expression of glutathione peroxidase 4 (P < 0.001). The training protocol also showed significant effects on the activity of hepatic antioxidant enzymes, although this action was greatly influenced by rat phenotype. The present data suggest that AIT protocol is a feasible strategy to improve some of the plasma and liver alterations featured by the MS.

Novel bisnaphthalimidopropyl (BNIPs) derivatives as anticancer compounds targeting DNA in human breast cancer cells.

Bisnaphthalimidopropyl (BNIP) derivatives are a family of compounds that exert anti-cancer activities in vitro and, according to previous studies, variations in the linker sequence have increased their DNA binding and cytotoxic activities. By modifying the linker sequence of bisnaphthalimidopropyl diaminodicyclohexylmethane (BNIPDaCHM), a previously synthesised BNIP derivative with anti-cancer properties, three novel BNIP derivatives were designed. Bisnaphthalimidopropyl-piperidylpropane (BNIPPiProp), a structural isomer of BNIPDaCHM, bisnaphthalimidopropyl ethylenedipiperidine dihydrobromide (BNIPPiEth), an isoform of BNIPDaCHM with a shorter linker chain, and (trans(trans))-bisnaphthalimidopropyl diaminodicyclohexylmethane (trans,trans-BNIPDaCHM), a stereoisomer of BNIPDaCHM, were successfully synthesised (72.3-29.5% yield) and characterised by nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS). Competitive displacement of ethidium bromide (EtBr) and UV binding studies were used to study the interactions of BNIP derivatives with Calf Thymus DNA. The cytotoxicity of these derivatives was assessed against human breast cancer MDA-MB-231 and SKBR-3 cells by MTT assay. Propidium iodide (PI) flow cytometry was conducted in order to evaluate the cellular DNA content in both breast cancer cell lines before and after treatment with BNIPs. The results showed that all novel BNIPs exhibit strong DNA binding properties in vitro, and strong cytotoxicity, with IC50 values in the range of 0.2-3.3 μM after 24 hours drug treatment. Two of the novel BNIP derivatives, BNIPPiEth and trans,trans-BNIPDaCHM, exhibited greater cytotoxicity against the two breast cancer cell lines studied, compared to BNIPDaCHM. By synthesising enantiopures and reducing the length of the linker sequence, the cytotoxicity of the BNIP derivatives was significantly improved compared to BNIPDaCHM, while maintaining DNA binding and bis-intercalating properties. In addition, cell cycle studies indicated that trans,trans-BNIPDaCHM, the most cytotoxic BNIP derivative, induced sub-G1 cell cycle arrest, indicative of apoptotic cell death. Based on these findings, further investigation is under way to assess the potential efficacy of trans,trans-BNIPDaCHM and BNIPPiEth in treating human breast cancer.

Bisnaphthalimidopropyl diaminodicyclohexylmethane induces DNA damage and repair instability in triple negative breast cancer cells via p21 expression

Bisnaphthalimidopropyl diaminodicyclohexylmethane (BNIPDaCHM) bisintercalates to DNA and is a potential anti-cancer therapeutic. In an attempt to elucidate the mechanism(s) underlying the potential of BNIPDaCHM; earlier work was extended to investigate its effect on DNA damage and repair as well as cell cycle modulation, in a triple negative breast cancer (TNBC) cell line in vitro. BNIPDaCHM significantly decreased cell viability in a concentration (≥ 5 μM) and time (≥ 24 h) dependent manner. The mechanism of this growth inhibition involved alterations to cell cycle progression, an increase in the sub-G1 population and changes to plasma membrane integrity/permeability observed by flow cytometry and fluorescence microscopy with acridine orange/ethidium bromide staining. Using single cell gel electrophoresis (Comet assay) and fluorescence microscopy to detect γ-H2AX-foci expression; it was found that after 4 h, ≥ 0.1 μM BNIPDaCHM treatment-induced significant DNA double strand breaks (DSBs). Moreover, exposure to a non-genotoxic concentration of BNIPDaCHM induced a significant decrease in the repair of oxidative DNA strand breaks induced by hydrogen peroxide. Also, BNIPDaCHM-treatment induced a significant time dependent increase in p21(Waf/Cip1) mRNA expression but, did not alter p53 mRNA expression. In conclusion, BNIPDaCHM treatment in MDA-MB-231 cells was associated with a significant induction of DNA DSBs and inhibition of DNA repair at non-genotoxic concentrations via p53-independent expression of p21(Waf1/Cip1). The latter may be a consequence of novel interactions between BNIPDaCHM and MDA-MB-231 cells which adds to the spectrum of therapeutically relevant activities that may be exploited in the future design and development of naphthalimide-based therapeutics.

Revalorisation of rapeseed pomace extracts: An in vitro study into its anti-oxidant and DNA protective properties

Rapeseed pomace (RSP) is a waste product obtained after edible oil production from Brassica napus. Analysis of ubiquitous secondary metabolites in RSP samples (two breeds, harvested in 2012/2014 respectively from North East of Scotland) and their ethanol/water (95:5) Soxhlet extracts were carried out. Soxhlet extraction of the RSP (petroleum ether followed by 95% ethanol) gave a solid extract. LC-MS/MS data of the extracts revealed several secondary metabolites, with Sinapic acid being the most abundant. Strong antioxidant activities of the Soxhlet extracts were confirmed from the results obtained in the FRAP, DPPH and ORAC assays. Furthermore, for the very first time, RSP extracts (13.9µg/ml) provided complete DNA protection, from oxidative stress induced by AAPH (3.5mM). Therefore the strong antioxidant and DNA protecting properties demonstrated by the RSP extracts in this study warrants further investigation for their revalorisation and potential use as reliable source of antioxidants in different food applications.

Study into the polyphenol content and antioxidant activity of rapeseed pomace extracts

Rapeseed pomace (RSP) is a waste product obtained after edible oil production from Brassica napus. This study aimed to determine the polyphenol content, radical scavenging activity, ferric iron reducing antioxidant power and the oxygen-radical absorbance capacity assay, of RSP extracts, with regard to their potential application in the treatment or prevention of neurodegenerative diseases. High performance liquid chromatography/mass spectrometry was applied to determine ubiquitous polyphenolic compounds. Three different extraction methods (Soxhlet-, ultra sonic assistedand accelerated solvent extractions) were applied on 2 harvest years (2012, 2014). From the extracts obtained, the total phenolic content (Folin–Ciocalteu assay) was found to be between 5·54 (SD 0·28) and 2·48 (SD 0·06) gallic acid equivalents/100 mg dry weight. The ferric iron reducing antioxidant power (FRAP assay) is ranging from 0·834 (SD 0·01) to 0·34 (SD 0·01) Trolox equivalents/100μg. The IC50 values for the radical scavenging (DPPH) assay were found to be between 49·23 (SD 14·00) and 180·30 (SD 16·16) μg/mL. Liquid chromatography-mass spectrometry of the RSP extracts showed substantial presence of several phenolic compounds, the most abundant one being sinapic acid (7496·7 (SD198·9) − 1923·3 (SD18·4) mg/kg). Significant differences (2-way ANOVA, p < 0·0001) were found between the 3 different extraction techniques for all the tested antioxidant properties. The strong antioxidant properties demonstrated by the RSP extracts in this study warrants further investigation for their potential use in the treatment or prevention of oxidative stress related diseases.

Can selenium supplementation modify oxidative stress in-vitro? A role for selenium supplementation in the prevention of cardiovascular disease

Background Two thirds of the UK population are either overweight or obese (body mass index (BMI) 25-29.9 and >30 kg/m respectively) and are typically characterised by systemic oxidative stress (OS); deemed to play a key role in cardiovascular disease (CVD) development. OS results from chronically high reactive oxidative species (ROS) formation and reduced antioxidant status. OS plays a key role in CVD development by initiating atherosclerosis (fatty plaque accumulation within the arterial walls); therefore obese individuals are at increased risk of atherosclerosis development. Increased monocyte ROS generation instigates atherosclerotic plaque formation by increasing the recruitment, binding and transmigration of monocytes across arterial endothelial cells and into the arterial wall. An increased dietary antioxidant intake or up-regulation of endogenous antioxidant enzymes may counteract this OS state and therefore lower CVD risk. Selenium is an essential dietary micronutrient incorporated within the catalytic site of endogenous antioxidant Glutathione Peroxidase (GPx) enzymes, which protect cells from OS and consequent cell damage. There is, however, a lack of knowledge concerning the effect of selenium supplementation in an OS state representative of sedentary overweight/obese individuals. The aim of this work was to investigate the ability of selenium supplementation to modify monocyte cell viability/ROS production under OS. Materials and methods U937 monocyte cells were supplemented with sodium selenite (Na2SeO3; 100nM or 200nM) or not and cultured for 48 hours at 37°C. Paraquat (100mM) and S-Nitroso-Nacetyl-DL-penicillamine (10mM) (PQ/SNAP) were added to the cells to induce OS. Cell viability was assessed via MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay while ROS production was determined by Flow Cytometry using the reagent CM-H2DC-FDA.