Identification of Anti-Neuroinflammatory Bioactive Compounds in Essential Oils and Aqueous Distillation Residues Obtained from Commercial Varieties of Cannabis sativa L

Neuroinflammation, which is mainly triggered by microglia, is a key contributor to multiple neurodegenerative diseases. Natural products, and in particular Cannabis sativa L., due to its richness in phytochemical components, represent ideal candidates to counteract neuroinflammation. We previously characterized different C. sativa commercial varieties which showed significantly different chemical profiles. On these bases, the aim of this study was to evaluate essential oils and aqueous distillation residues from the inflorescences of three different hemp varieties for their anti-neuroinflammatory activity in BV-2 microglial cells. Cells were pretreated with aqueous residues or essential oils and then activated with LPS. Unlike essential oils, aqueous residues showed negligible effects in terms of anti-inflammatory activity. Among the essential oils, the one obtained from 'Gorilla Glue' was the most effective in inhibiting pro-inflammatory mediators and in upregulating anti-inflammatory ones through the modulation of the p38 MAPK/NF-κB pathway. Moreover, the sesquiterpenes (E)-caryophyllene, α-humulene, and caryophyllene oxide were identified as the main contributors to the essential oils' anti-inflammatory activity. To our knowledge, the anti-neuroinflammatory activity of α-humulene has not been previously described. In conclusion, our work shows that C. sativa essential oils characterized by high levels of sesquiterpenes can be promising candidates in the prevention/counteraction of neuroinflammation.

Myrcene: A Natural Compound Showing Anticancer Activity in HeLa Cells

γ-terpinene, α-terpinene, p-cymene, and myrcene are monoterpenes found in many essential oils extracted from a variety of plants and spices. Myrcene also occurs naturally in plants such as hops, cannabis, lemongrass, and verbena and is used as a flavoring agent in food and beverage manufacturing. In this research, the biological efficacy of γ-terpinene, α-terpinene, p-cymene, and myrcene was studied in human cell lines (HeLa, SH-SY5Y, and HDFa). Cytotoxicity, cell proliferation, cell migration, and morphology assays were performed to obtain detailed information on the anticancer properties. Our results show that myrcene has potential biological activity, especially in HeLa cells. In this cell line, it leads to an arrest of proliferation, a decrease in motility and morphological changes with loss of sphericity and thickness, and DNA damage. In addition, the interaction of γ-terpinene, α-terpinene, p-terpinene, and myrcene with calf thymus DNA (ct-DNA) was studied by UV-visible spectrophotometry. DNA binding experiments show that only myrcene can interact with DNA with an apparent dissociation constant (Kd) of 29 × 10-6 M.

By-Product Extracts from Castanea sativa Counteract Hallmarks of Neuroinflammation in a Microglial Model

Castanea sativa is very common in Italy, and the large amount of waste material generated during chestnut processing has a high environmental impact. Several studies demonstrated that chestnut by-products are a good source of bioactive compounds, mainly endowed with antioxidant properties. This study further investigates the anti-neuroinflammatory effect of chestnut leaf and spiny bur extracts, together with the deepest phytochemical characterisation (by NMR and MS) of active biomolecules contained in leaf extracts, which resulted in being more effective than spiny bur ones. BV-2 microglial cells stimulated with lipopolysaccharide (LPS) were used as a model of neuroinflammation. In BV-2 cells pre-treated with chestnut extracts, LPS signalling is partially blocked via the reduced expression of TLR4 and CD14 as well as the expression of LPS-induced inflammatory markers. Leaf extract fractions revealed the presence of specific flavonoids, such as isorhamnetin glucoside, astragalin, myricitrin, kaempferol 3-rhamnosyl (1-6)(2″-trans-p-coumaroyl)hexoside, tiliroside and unsaturated fatty acids, all of which could be responsible for the observed anti-neuroinflammatory effects. Interestingly, the kaempferol derivative has been identified in chestnut for the first time. In conclusion, the exploitation of chestnut by-products is suitable for the achievement of two goals: satisfaction of consumers’ demand for new, natural bio-active compounds and valorisation of by-products.

Mechanisms Underlying Neurodegenerative Disorders and Potential Neuroprotective Activity of Agrifood By-Products

Neurodegenerative diseases, characterized by progressive loss in selected areas of the nervous system, are becoming increasingly prevalent worldwide due to an aging population. Despite their diverse clinical manifestations, neurodegenerative diseases are multifactorial disorders with standard features and mechanisms such as abnormal protein aggregation, mitochondrial dysfunction, oxidative stress and inflammation. As there are no effective treatments to counteract neurodegenerative diseases, increasing interest has been directed to the potential neuroprotective activities of plant-derived compounds found abundantly in food and in agrifood by-products. Food waste has an extremely negative impact on the environment, and recycling is needed to promote their disposal and overcome this problem. Many studies have been carried out to develop green and effective strategies to extract bioactive compounds from food by-products, such as peel, leaves, seeds, bran, kernel, pomace, and oil cake, and to investigate their biological activity. In this review, we focused on the potential neuroprotective activity of agrifood wastes obtained by common products widely produced and consumed in Italy, such as grapes, coffee, tomatoes, olives, chestnuts, onions, apples, and pomegranates.

Strategies to Counteract Oxidative Stress and Inflammation in Chronic-Degenerative Diseases

The great increase in life expectancy is linked to the necessity of counteracting chronic-degenerative diseases, e [...].

Acid Sphingomyelinase Controls Early Phases of Skeletal Muscle Regeneration by Shaping the Macrophage Phenotype

Skeletal muscle regeneration is a complex process involving crosstalk between immune cells and myogenic precursor cells, i.e., satellite cells. In this scenario, macrophage recruitment in damaged muscles is a mandatory step for tissue repair since pro-inflammatory M1 macrophages promote the activation of satellite cells, stimulating their proliferation and then, after switching into anti-inflammatory M2 macrophages, they prompt satellite cells' differentiation into myotubes and resolve inflammation. Here, we show that acid sphingomyelinase (ASMase), a key enzyme in sphingolipid metabolism, is activated after skeletal muscle injury induced in vivo by the injection of cardiotoxin. ASMase ablation shortens the early phases of skeletal muscle regeneration without affecting satellite cell behavior. Of interest, ASMase regulates the balance between M1 and M2 macrophages in the injured muscles so that the absence of the enzyme reduces inflammation. The analysis of macrophage populations indicates that these events depend on the altered polarization of M1 macrophages towards an M2 phenotype. Our results unravel a novel role of ASMase in regulating immune response during muscle regeneration/repair and suggest ASMase as a supplemental therapeutic target in conditions of redundant inflammation that impairs muscle recovery.

NADPH Oxidases: Redox Regulators of Stem Cell Fate and Function

One of the major sources of reactive oxygen species (ROS) generated within stem cells is the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family of enzymes (NOXs), which are critical determinants of the redox state beside antioxidant defense mechanisms. This balance is involved in another one that regulates stem cell fate: indeed, self-renewal, proliferation, and differentiation are decisive steps for stem cells during embryo development, adult tissue renovation, and cell therapy application. Ex vivo culture-expanded stem cells are being investigated for tissue repair and immune modulation, but events such as aging, senescence, and oxidative stress reduce their ex vivo proliferation, which is crucial for their clinical applications. Here, we review the role of NOX-derived ROS in stem cell biology and functions, focusing on positive and negative effects triggered by the activity of different NOX isoforms. We report recent findings on downstream molecular targets of NOX-ROS signaling that can modulate stem cell homeostasis and lineage commitment and discuss the implications in ex vivo expansion and in vivo engraftment, function, and longevity. This review highlights the role of NOX as a pivotal regulator of several stem cell populations, and we conclude that these aspects have important implications in the clinical utility of stem cells, but further studies on the effects of pharmacological modulation of NOX in human stem cells are imperative.

Magnesium: Biochemistry, Nutrition, Detection, and Social Impact of Diseases Linked to Its Deficiency

Magnesium plays an important role in many physiological functions. Habitually low intakes of magnesium and in general the deficiency of this micronutrient induce changes in biochemical pathways that can increase the risk of illness and, in particular, chronic degenerative diseases. The assessment of magnesium status is consequently of great importance, however, its evaluation is difficult. The measurement of serum magnesium concentration is the most commonly used and readily available method for assessing magnesium status, even if serum levels have no reliable correlation with total body magnesium levels or concentrations in specific tissues. Therefore, this review offers an overview of recent insights into magnesium from multiple perspectives. Starting from a biochemical point of view, it aims at highlighting the risk due to insufficient uptake (frequently due to the low content of magnesium in the modern western diet), at suggesting strategies to reach the recommended dietary reference values, and at focusing on the importance of detecting physiological or pathological levels of magnesium in various body districts, in order to counteract the social impact of diseases linked to magnesium deficiency.

Genomic adaptations to cereal-based diets contribute to mitigate metabolic risk in some human populations of East Asian ancestry

Adoption of diets based on some cereals, especially on rice, signified an iconic change in nutritional habits for many Asian populations and a relevant challenge for their capability to maintain glucose homeostasis. Indeed, rice shows the highest carbohydrates content and glycemic index among the domesticated cereals and its usual ingestion represents a potential risk factor for developing insulin resistance and related metabolic diseases. Nevertheless, type 2 diabetes and obesity epidemiological patterns differ among Asian populations that rely on rice as a staple food, with higher diabetes prevalence and increased levels of central adiposity observed in people of South Asian ancestry rather than in East Asians. This may be at least partly due to the fact that populations from East Asian regions where wild rice or other cereals such as millet have been already consumed before their cultivation and/or were early domesticated have relied on these nutritional resources for a period long enough to have possibly evolved biological adaptations that counteract their detrimental side effects. To test such a hypothesis, we compared adaptive evolution of these populations with that of control groups from regions where the adoption of cereal-based diets occurred many thousand years later and which were identified from a genome-wide dataset including 2,379 individuals from 124 East Asian and South Asian populations. This revealed selective sweeps and polygenic adaptive mechanisms affecting functional pathways involved in fatty acids metabolism, cholesterol/triglycerides biosynthesis from carbohydrates, regulation of glucose homeostasis, and production of retinoic acid in Chinese Han and Tujia ethnic groups, as well as in people of Korean and Japanese ancestry. Accordingly, long-standing rice- and/or millet-based diets have possibly contributed to trigger the evolution of such biological adaptations, which might represent one of the factors that play a role in mitigating the metabolic risk of these East Asian populations.

Freeze-Dried Matrices for Buccal Administration of Propranolol in Children: Physico-Chemical and Functional Characterization

Buccal matrices represent a widely accepted dosage form permitting a convenient, easy, reliable drug administration and reducing administration errors. The aim of this study was the development of mucoadhesive buccal matrices for propranolol administration in children. Matrices were obtained by freeze-drying of drug loaded polymeric solutions based on gum tragacanth (GT), pectin (PEC), hydroxypropylmethylcellulose (HPMC), sodium hyaluronate (HA), gelatin (GEL), chitosan (CH) or a mixture of CH and HPMC (CH/HPMC). Matrices were characterized for drug solid state, morphology, water-uptake, mucoadhesion ability, in vitro drug release and permeation through porcine epithelium. The most promising formulations were tested for in vitro biocompatibility in human dental pulp fibroblasts. The preparative method and the polymeric composition influenced the drug solid state, as a complete amorphization as well as different polymorphic forms were observed. GEL and PEC guaranteed a fast and complete drug release due to their rapid dissolution, while for the other matrices the release was influenced by drug diffusion through the viscous gelled matrix. Moreover, matrices based on CH and CH/HPMC showed the best mucoadhesive properties, favoured the drug permeation, in virtue of CH ability to interfere with the lipid organization of biological membrane, and were characterized by a good biocompatibility profile.

Leaves and Spiny Burs of Castanea Sativa from an Experimental Chestnut Grove: Metabolomic Analysis and Anti-Neuroinflammatory Activity

Castanea sativa cultivation has been present in Mediterranean regions since ancient times. In order to promote a circular economy, it is of great importance to valorize chestnut groves' by-products. In this study, leaves and spiny burs from twenty-four Castanea trees were analyzed by 1H NMR metabolomics to provide an overview of their phytochemical profile. The Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) performed on these data allowed us to distinguish 'Marrone' from 'Castagna', since the latter were generally more enriched with secondary metabolites, in particular, flavonoids (astragalin, isorhamnetin glucoside, and myricitrin) were dominant. Knowing that microglia are involved in mediating the oxidative and inflammatory response of the central nervous system, the potential anti-inflammatory effects of extracts derived from leaves and spiny burs were evaluated in a neuroinflammatory cell model: BV-2 microglia cells. The tested extracts showed cytoprotective activity (at 0.1 and 0.5 mg/mL) after inflammation induction by 5 µg/mL lipopolysaccharide (LPS). In addition, the transcriptional levels of IL-1β, TNF-α, and NF-kB expression induced by LPS were significantly decreased by cell incubation with spiny burs and leaves extracts. Taken together, the obtained results are promising and represent an important step to encourage recycling and valorization of chestnut byproducts, usually considered "waste".

Solid Lipid Microparticles for Oral Delivery of Catalase: Focus on the Protein Structural Integrity and Gastric Protection

Protein inactivation either during the production process or along the gastrointestinal tract is the major problem associated with the development of oral delivery systems for biological drugs. This work presents an evaluation of the structural integrity and the biological activity of a model protein, catalase, after its encapsulation in glyceryl trimyristate-based solid lipid microparticles (SLMs) obtained by the spray congealing technology. Circular dichroism and fluorescence spectroscopies were used to assess the integrity of catalase released from SLMs. The results confirmed that no conformational change occurred during the production process and both the secondary and tertiary structures were retained. Catalase is highly sensitive to temperature and undergoes denaturation above 60 °C; nevertheless, spray congealing allowed the retention of most biological activity due to the loading of the drug at the solid state, markedly reducing the risk of denaturation. Catalase activity after exposure to simulated gastric conditions (considering both acidic pH and the presence of gastric digestive hydrolases) ranged from 35 to 95% depending on the carrier: increasing of both the fatty acid chain length and the degree of substitution of the glyceride enhanced residual enzyme activity. SLMs allowed the protein release in a simulated intestinal environment and were not cytotoxic against HT29 cells. In conclusion, the encapsulation of proteins into SLMs by spray congealing might be a promising strategy for the formulation of nontoxic and inexpensive oral biotherapeutic products.

Role of Mesenchymal Stem Cells in Counteracting Oxidative Stress-Related Neurodegeneration

Neurodegenerative diseases include a variety of pathologies such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, amyotrophic lateral sclerosis, and so forth, which share many common characteristics such as oxidative stress, glycation, abnormal protein deposition, inflammation, and progressive neuronal loss. The last century has witnessed significant research to identify mechanisms and risk factors contributing to the complex etiopathogenesis of neurodegenerative diseases, such as genetic, vascular/metabolic, and lifestyle-related factors, which often co-occur and interact with each other. Apart from several environmental or genetic factors, in recent years, much evidence hints that impairment in redox homeostasis is a common mechanism in different neurological diseases. However, from a pharmacological perspective, oxidative stress is a difficult target, and antioxidants, the only strategy used so far, have been ineffective or even provoked side effects. In this review, we report an analysis of the recent literature on the role of oxidative stress in Alzheimer’s and Parkinson’s diseases as well as in amyotrophic lateral sclerosis, retinal ganglion cells, and ataxia. Moreover, the contribution of stem cells has been widely explored, looking at their potential in neuronal differentiation and reporting findings on their application in fighting oxidative stress in different neurodegenerative diseases. In particular, the exposure to mesenchymal stem cells or their secretome can be considered as a promising therapeutic strategy to enhance antioxidant capacity and neurotrophin expression while inhibiting pro-inflammatory cytokine secretion, which are common aspects of neurodegenerative pathologies. Further studies are needed to identify a tailored approach for each neurodegenerative disease in order to design more effective stem cell therapeutic strategies to prevent a broad range of neurodegenerative disorders.

Natural Compounds as a Strategy to Optimize "In Vitro" Expansion of Stem Cells

The efficient use of stem cells for transplantation is often limited by the relatively low number of stem cells collected. The ex vivo expansion of human stem cells for clinical use is a potentially valuable approach to increase stem cell number. Currently, most of the procedures used to expand stem cells are carried out using a 21% oxygen concentration, which is about 4- to 10-fold greater than the concentration characteristic of their natural niches. Hyperoxia might cause oxidative stress with a deleterious effect on the physiology of cultured stem cells. In this review, we investigate and critically examine the available information on the ability of natural compounds to counteract hyperoxia-induced damage in different types of stem cells ex vivo. In particular, we focused on proliferation and stemness maintenance in an attempt to draw up useful indications to define new culture media with a promoting activity on cell expansion in vitro.

Glutathione-Loaded Solid Lipid Microparticles as Innovative Delivery System for Oral Antioxidant Therapy

The present study aimed to develop a novel formulation containing glutathione (GSH) as an oral antioxidant therapy for the treatment of oxidative stress-related intestinal diseases. To this purpose, solid lipid microparticles (SLMs) with Dynasan 114 and a mixture of Dynasan 114 and Dynasan 118 were produced by spray congealing technology. The obtained SLMs had main particle sizes ranging from 250 to 355 µm, suitable for oral administration. GSH was efficiently loaded into the SLMs at 5% or 20% w/w and the encapsulation process did not modify its chemico-physical properties, as demonstrated by FT-IR, DSC and HSM analysis. Moreover, in vitro release studies using biorelevant media showed that Dynasan 114-based SLMs could efficiently release GSH in various intestinal fluids, while 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay demonstrated the good radical scavenging activity of this formulation. Dynasan 114-based SLMs exhibited an excellent biocompatibility on intestinal HT-29 cells at concentrations up to 2000 μg/mL. SLMs containing GSH alone or together with another antioxidant agent (catalase) were effective in reducing intracellular reactive oxygen species (ROS) levels. Overall, this study indicated that spray congealed SLMs are a promising oral drug delivery system for the encapsulation of one or more biological antioxidant agents for local intestinal treatment.

Isolation and Characterization of Wheat Derived Nonspecific Lipid Transfer Protein 2 (nsLTP2)

Numerous studies support the protective role of bioactive peptides against cardiovascular diseases. Cereals represent the primary source of carbohydrates, but they also contain substantial amounts of proteins, therefore representing a potential dietary source of bioactive peptides with nutraceutical activities. The analysis of wheat extracts purified by chromatographic techniques by means of HPLC-UV/nanoLC-nanoESI-QTOF allowed the identification of a signal of about 7 kDa which, following data base searches, was ascribed to a nonspecific lipid-transfer protein (nsLTP) type 2 from Triticum aestivum (sequence coverage of 92%). For the first time nsLTP2 biological activities have been investigated. In particular, in experiments with human umbilical vein endothelial cells (HUVEC), nsLTP2 displayed antioxidant and cytoprotective activities, being able to significantly decrease reactive oxygen species (ROS) levels and to reduce lactate dehydrogenase (LDH) release, generated following oxidative (hydrogen peroxide) and inflammatory (tumor necrosis factor α, interleukin-1β, and lipopolysaccharide) stimulation. The obtained promising results suggest potential protective role of nsLTP2 in vascular diseases prevention. PRACTICAL APPLICATION: nsLTP 2 peptide is resistant to proteases throughout the gastrointestinal tract and exerts antioxidant and cytoprotective activities. These characteristics could be exploited in vascular diseases prevention.

Investigation on the Effects of Antimicrobial imidazo[2,1-b]thiazole Derivatives on the Genitourinary Microflora

BACKGROUND

Fused five-membered heterocyclic rings containing bridgehead nitrogen atom are particularly versatile in the field of medicinal chemistry because of their different biological activities. Among them, the imidazo[2,1-b]thiazole is an attractive fused heterocyclic core that has been extensively studied.

OBJECTIVE

The aim of the current study was to study the therapeutic applications of imidazo[2,1- b]thiazole derivatives as antimicrobial agents for the treatment of genitourinary infections.

METHOD

A traditional synthetic methodology was involved to obtain a small series of imidazothiazole derivatives.

RESULTS

Herein, we report the antimicrobial activity of the imidazo[2,1-b]thiazole or imidazo[2,1- b]thiazolidine derivatives against selected fungi, Gram-positive and Gram-negative bacteria. Moreover, experiments were carried out to investigate the interference towards the endogenous microbiota.

CONCLUSION

The most interesting of the series are the thiocyano derivatives (19, 23) showing a good profile for the treatment of genitourinary infections: a spectrum of activity covering both bacteria and fungi together with a reduced impact versus critical lines of Lactobacillus exerting defense against pathogens.

Glycosides from Stevia rebaudiana Bertoni Possess Insulin-Mimetic and Antioxidant Activities in Rat Cardiac Fibroblasts

Stevia rebaudiana Bertoni is a shrub having a high content of sweet diterpenoid glycosides in its leaves, mainly stevioside and rebaudioside A, which are used as noncaloric, natural sweeteners. The aim of this study was to deepen the knowledge about the insulin-mimetic effect exerted by four different mixtures of steviol glycosides, rich in stevioside and rebaudioside A, in neonatal rat cardiac fibroblasts. The potential antioxidant activity of these steviol glycosides was also assessed, as oxidative stress is associated with diabetes. Likewise the insulin effect, steviol glycosides caused an increase in glucose uptake into rat fibroblasts by activating the PI3K/Akt pathway, thus inducing Glut4 translocation to the plasma membrane. The presence of S961, an insulin antagonist, completely abolished these effects, allowing to hypothesize that steviol glycosides could act as ligands of the same receptor engaged by insulin. Moreover, steviol glycosides counteracted oxidative stress by increasing reduced glutathione intracellular levels and upregulating expression and activity of the two antioxidant enzymes superoxide dismutase and catalase. The present work unravels the insulin-mimetic effect and the antioxidant property exerted by steviol glycosides, suggesting their potential beneficial role in the cotreatment of diabetes and in health maintenance.

Intracellular cysteine oxidation is modulated by aquaporin-8-mediated hydrogen peroxide channeling in leukaemia cells

The modulation of H₂ O₂ production by NADPH oxidase (Nox), on vascular endothelial growth factor (VEGF) stimulation, affects the redox signaling linked to cancer cell proliferation. H₂ O₂ signal transduction involves reversible oxidation of thiol proteins, leading to the formation of cysteine sulfenic acids, responsible for the temporary inactivation of many phosphatases. These events imply that H₂ O₂ reaches its intracellular targets. As Aquaporin-8 (AQP8) has been demonstrated to funnel Nox-produced H₂ O₂ across the plasma membrane, this study aims to elucidate the role of AQP8 in the redox signaling occurring in human leukaemia B1647 cells that constitutively produce VEGF. AQP8 overexpression or silencing resulted in the modulation of VEGF ability of increasing or decreasing, respectively, H₂ O₂ intracellular level. Moreover, data obtained by a dimedone-based immunochemical method for sulfenic acid detection demonstrate that the expression of AQP8 can modulate the amplitude of downstream events, altering the activity of redox-sensitive targets. In particular, AQP8 affected VEGF-induced redox signaling by increasing the sulfenation of the tumor suppressor PTEN, which resulted in its inactivation and, in turn, caused Akt activation. Therefore, the dimedone-based method for easily monitoring cellular protein sulfenation allowed to demonstrate, for the first time, the role of AQP8 on the fine tune of cysteine oxidation in target proteins involved in leukaemia cell proliferation pathways. © 2016 BioFactors, 43(2):232-242, 2017.

Lunasin in wheat: a chemical and molecular study on its presence or absence

Lunasin is a peptide whose anticancer properties are widely reported. Originally isolated from soybean seeds, lunasin was also found in cereal (wheat, rye, barley and Triticale), Solanum and amaranthus seeds. However, it was recently reported that searches of transcript and DNA sequence databases for wheat and other cereals failed to identify sequences with similarity to those encoding the lunasin peptide in soy. In order to clarify the presence or absence of lunasin in wheat varieties, a broad investigation based on chemical (LC-ESI-MS) and molecular (PCR) analyses was conducted. Both approaches pointed out the absence of lunasin in the investigated wheat genotypes; in particular no compounds with a molecular weight similar to that of lunasin standard and no lunasin-related sequences were found in the analysed wheat samples. These findings confirm the hypothesis, reported in recent researches, that lunasin is not a wheat-derived peptide.

Specific aquaporins facilitate Nox-produced hydrogen peroxide transport through plasma membrane in leukaemia cells

In the last decade, the generation and the role of reactive oxygen species (ROS), particularly hydrogen peroxide, in cell signalling transduction pathways have been intensively studied, and it is now clear that an increase of ROS level affects cellular growth and proliferation pathways related to cancer development. Hydrogen peroxide (H2O2) has been long thought to permeate biological membranes by simple diffusion since recent evidence challenged this notion disclosing the role of aquaporin water channels (AQP) in mediating H2O2 transport across plasma membranes. We previously demonstrated that NAD(P)H oxidase (Nox)-generated ROS sustain glucose uptake and cellular proliferation in leukaemia cells. The aim of this study was to assess whether specific AQP isoforms can channel Nox-produced H2O2 across the plasma membrane of leukaemia cells affecting downstream pathways linked to cell proliferation. In this work, we demonstrate that AQP inhibition caused a decrease in intracellular ROS accumulation in leukaemia cells both when H2O2 was produced by Nox enzymes and when it was exogenously added. Furthermore, AQP8 overexpression or silencing resulted to modulate VEGF capacity of triggering an H2O2 intracellular level increase or decrease, respectively. Finally, we report that AQP8 is capable of increasing H2O2-induced phosphorylation of both PI3K and p38 MAPK and that AQP8 expression affected positively cell proliferation. Taken together, the results here reported indicate that AQP8 is able to modulate H2O2 transport through the plasma membrane affecting redox signalling linked to leukaemia cell proliferation.

Cytotoxic activities of substituted 3-(3,4,5-trimethoxybenzylidene)-1,3-dihydroindol-2-ones and studies on their mechanisms of action

The synthesis of new trimethoxybenzylidene-indolinones is reported. Their cytotoxic activity was evaluated according to Developmental Therapeutics Program, National Cancer Institute, Bethesda, MD, drug screen protocols. The study of the mechanism of action suggests that inhibition of Nox4 in B1647 cells (acute myeloid leukemia) could contribute to the antiproliferative effect of some compounds. Moreover, inhibition of tubulin assembly was observed for the most cytotoxic compound, and the structural basis for this activity was delineated by binding models.

Phytochemical profile and nutraceutical value of old and modern common wheat cultivars

Among health-promoting phytochemicals in whole grains, phenolic compounds have gained attention as they have strong antioxidant properties and can protect against many degenerative diseases. Aim of this study was to profile grain phenolic extracts of one modern and five old common wheat (Triticum aestivum L.) varieties and to evaluate their potential antiproliferative or cytoprotective effect in different cell culture systems.Wheat extracts were characterized in terms of antioxidant activity and phenolic composition (HPLC/ESI-TOF-MS profile, polyphenol and flavonoid contents). Results showed that antioxidant activity (FRAP and DPPH) is mostly influenced by flavonoid (both bound and free) content and by the ratio flavonoids/polyphenols. Using a leukemic cell line, HL60, and primary cultures of neonatal rat cardiomyocytes, the potential antiproliferative or cytoprotective effects of different wheat genotypes were evaluated in terms of intracellular reactive oxygen species levels and cell viability. All tested wheat phenolic extracts exerted dose-dependent cytoprotective and antiproliferative effects on cardiomyocytes and HL60 cells, respectively. Due to the peculiar phenolic pattern of each wheat variety, a significant genotype effect was highlighted. On the whole, the most relevant scavenging effect was found for the old variety Verna. No significant differences in terms of anti-proliferative activities among wheat genotypes was observed.Results reported in this study evidenced a correspondence between the in vitro antioxidant activity and potential healthy properties of different extracts. This suggests that an increased intake of wheat grain derived products could represent an effective strategy to achieve both chemoprevention and protection against oxidative stress related diseases.

Effect of plasma membrane cholesterol depletion on glucose transport regulation in leukemia cells

GLUT1 is the predominant glucose transporter in leukemia cells, and the modulation of glucose transport activity by cytokines, oncogenes or metabolic stresses is essential for their survival and proliferation. However, the molecular mechanisms allowing to control GLUT1 trafficking and degradation are still under debate. In this study we investigated whether plasma membrane cholesterol depletion plays a role in glucose transport activity in M07e cells, a human megakaryocytic leukemia line. To this purpose, the effect of cholesterol depletion by methyl-β-cyclodextrin (MBCD) on both GLUT1 activity and trafficking was compared to that of the cytokine Stem Cell Factor (SCF). Results show that, like SCF, MBCD led to an increased glucose transport rate and caused a subcellular redistribution of GLUT1, recruiting intracellular transporter molecules to the plasma membrane. Due to the role of caveolae/lipid rafts in GLUT1 stimulation in response to many stimuli, we have also investigated the GLUT1 distribution along the fractions obtained after non ionic detergent treatment and density gradient centrifugation, which was only slightly changed upon MBCD treatment. The data suggest that MBCD exerts its action via a cholesterol-dependent mechanism that ultimately results in augmented GLUT1 translocation. Moreover, cholesterol depletion triggers GLUT1 translocation without the involvement of c-kit signalling pathway, in fact MBCD effect does not involve Akt and PLCγ phosphorylation. These data, together with the observation that the combined MBCD/SCF cell treatment caused an additive effect on glucose uptake, suggest that the action of SCF and MBCD may proceed through two distinct mechanisms, the former following a signalling pathway, and the latter possibly involving a novel cholesterol dependent mechanism.

NAD(P)H oxidase isoform Nox2 plays a prosurvival role in human leukaemia cells

The mechanism involved in the prosurvival effect of interleukin-3 on the human acute myeloid leukaemia cell line M07e is investigated. A decrease in intracellular reactive oxygen species (ROS) content, glucose transport activity and cell survival was observed in the presence of inhibitors of plasma membrane ROS sources, such as diphenylene iodonium and apocynin, and by small interference RNA for Nox2. Moreover, IL-3 incubation stimulated the synthesis of Nox2 cytosolic sub-unit p47phox and glucose transporter Glut1. Thus, the inhibition of ROS generation by Nox inhibitors stimulated apoptosis showing that ROS production, induced by IL-3 via Nox2, protects leukaemic cells from cell death. Also incubation with receptor tyrosine kinase inhibitors, such as anti-leukaemic drugs blocking the stem cell factor receptor (c-kit), showed similar effects, hinting that IL-3 transmodulates c-kit phosphorylation. These mechanisms may play an important role in acute myeloid leukaemia treatment, representing a novel therapeutic target.

VEGF-induced ROS generation from NAD(P)H oxidases protects human leukemic cells from apoptosis

Vascular endothelial growth factor (VEGF) and reactive oxygen species (ROS) play critical roles in vascular pathophysiology and in hematological malignancies. VEGF is supposed to utilize ROS as messenger intermediates downstream of the VEGF receptor-2. NAD(P)H oxidase (Nox) family is a major source of cellular ROS and is implicated in increased ROS production in tumor cells. We previously demonstrated that B1647 cells, a human leukemic cell line, express Nox2 and Nox4, both at mRNA and protein level. We suggest here that the VEGF-induced increase in ROS can be related to Nox2 and Nox4 activities. Nox-derived ROS are involved in early signaling events such as the autophosphorylation of VEGF receptor-2, and in the modulation of glucose uptake, a cellular activity strictly bound to VEGF-induced leukemic cell proliferation, as shown by experiments with antioxidants and Nox inhibitors and siRNA. Nox-generated ROS are required to sustain B1647 cell viability and proliferation; in fact, antioxidants such as EUK-134 or Nox inhibitors and siRNA direct cells to apoptotic cell death, suggesting that manipulation of cellular Nox2 and Nox4 could affect survival of leukemic cells.

Inhibition of trans-plasma membrane electron transport: a potential anti-leukemic strategy

The recently demonstrated reliance of glycolytic cancer cells on trans-plasma membrane electron transport (tPMET) for survival raises the question of its suitability as a target for anticancer drug development. In this study, the effects of several new and known compounds on proliferation, tPMET activity and NAD(P)H intrinsic fluorescence in human myelogenous leukemic cell lines were investigated. The whole data confirm the importance of tPMET in leukemic cell survival and suggest this activity as a new potential anti-leukemic target.

Induction of apoptosis in a human leukemic cell line via reactive oxygen species modulation by antioxidants

In the human acute myeloid leukemia cell line M07e, the growth factor interleukin-3 (IL-3) induces ROS formation, positively affecting Glut1-mediated glucose uptake and cell survival. The effect of IL-3 and exogenous hydrogen peroxide on cell viability seems to be mediated through inhibition of the cell death commitment, as shown by apoptotic markers such as caspase activities, apoptotic nuclei, and changes in the amount of proteins belonging to the Bcl-2 family. The pivotal role of ROS is confirmed using various antioxidants, such as EUK-134, ebselen, TEMPO, and hydroxylamine probe. In fact, these antioxidants, acting through different mechanisms, decrease glucose transport activity and cell proliferation activated by IL-3 or by low concentrations of hydrogen peroxide. Moreover, antioxidants foster programmed cell death commitment, as shown by the cited apoptotic parameters. EUK-134, a combined superoxide dismutase/catalase mimetic, opposes the effects of IL-3 and H(2)O(2), decreasing phosphorylation levels of signaling enzymes such as Akt, Src tyrosine kinase, and ERK. Results show that ROS production induced by IL-3 can protect leukemic cells from apoptosis, the effect being counteracted by antioxidants. This mechanism may play an important role in supporting acute myeloid leukemia treatment, thus representing a novel therapeutic strategy.

Antitumor activity of bis-indole derivatives

This paper reports the synthesis of compounds formed by two indole systems separated by a heterocycle (pyridine or piperazine). As a primary screening, the new compounds were submitted to the National Cancer Institute for evaluation of antitumor activity in the human cell line screen. The pyridine derivatives were far more active than the piperazine derivatives. For the study of the mechanism of action, the most active compounds were subjected to COMPARE analysis and to further biological tests including proteasome inhibition and inhibition of plasma membrane electron transport. The compound bearing the 5-methoxy-2-indolinone moiety was subjected to the first in vivo experiment (hollow fiber assay) and was active. It was therefore selected for the second in vivo experiment (human tumor xenograft in mice). In conclusion we demonstrated that this approach was successful, since some of the compounds described are much more active than the numerous, so far prepared and tested 3-indolylmethylene-2-indolinones.

Effect of radical stress and ageing on the occurrence of trans fatty acids in rats fed a trans-free diet

In a previous paper, we demonstrated that tissue trans fatty acids can not only derive from the diet but also be endogenously formed. The central focus of this study was to prove that the in vivo isomerization occurs via a radical process. Two different models of radical insult were used: CCl(4) and AAPH injection to rats fed a diet completely free of trans isomers. Following this acute radical stress, a significant increase in unnatural trans fatty acid content of erythrocyte, kidney, and heart, but not liver, was observed. These results can be mainly explained by the high content, particularly in the liver, of antioxidant vitamins A and E that exhibit also an "anti-isomerizing" effect. Since during ageing cellular components are exposed to increasing radical insults, the observation of a significant trans fatty acid accumulation in 30-month-old rats could confirm that the in vivo formation of unnatural isomers is due to a radical process. Trans fatty acids can influence the physical characteristics of bilayer microdomains, affecting membrane properties and functions; thus, knowledge of biological radical species responsible for cis/trans isomerization and their possible sources can provide protective systems for preserving lipid geometry.

Glucose-transport regulation in leukemic cells: how can H2O2 mimic stem cell factor effects?

In leukemic cells, glucose transport is activated by SCF and H2O2 through a common signal cascade involving Akt, PLCgamma, Syk, and the Src family, in this order. An explanation can be provided by the phosphorylation of c-kit, the SCF receptor, elicited by either SCF or H2O2. Moreover, antioxidants prevent the SCF effect on glucose transport, confirming the involvement of H2O2 in the pathway leading to glucose-transport activation and suggesting a potential role for reactive oxygen species in leukemia proliferation.

Occurrence of trans fatty acids in rats fed a trans-free diet: a free radical-mediated formation?

Trans isomers of unsaturated fatty acids are absorbed from the diet, due to their presence in diary fat and hydrogenated vegetable oils, and health concern has risen due to their effects on lipid risk factors in cardiovascular diseases. On the basis of the efficiency of the thiyl-radical-catalyzed cis/trans isomerization in vitro and the presence of many sulfur-containing compounds in the cell, the aim of this study was to demonstrate that trans geometry of lipid double bonds can be endogenously generated within membrane phospholipids. The study reports trans fatty acids occurrence in tissue and erythrocyte phospholipids of young adult rats fed a diet completely free of trans isomers. Results show that tissues are differently prone to the endogenous isomerization and that, following a free radical attack, trans fatty acids can reach very high amounts. The effectiveness of this process is considerably inhibited in the presence of all-trans retinol, confirming previous data in model membranes. Our results suggest that geometrical isomerization of unsaturated fatty acids, which causes a structural modification of membrane lipids and may influence basic membrane properties and vital biochemical functions, can occur under radical stress conditions and could be efficiently prevented by vitamin A.

Activation of glucose transport during simulated ischemia in H9c2 cardiac myoblasts is mediated by protein kinase C isoforms

Glucose transport into cells may be regulated by a variety of conditions, including ischemia. We investigated whether some enzymes frequently involved in the metabolic adaptation to ischemia are also required for glucose transport activation. Ischemia was simulated by incubating during 3 h H9c2 cardiomyoblasts in a serum- and glucose-free medium in hypoxia. Under these conditions 2-deoxy-d-[2,6-(3)H]-glucose uptake was increased (57% above control levels, p<0.0001) consistently with GLUT1 and GLUT4 translocation to sarcolemma. Tyrosine kinases inhibition via tyrphostin had no effect on glucose transport up-regulation induced by simulated ischemia. On the other hand, chelerythrine, a broad range inhibitor of protein kinase C isoforms, and rottlerin, an inhibitor of protein kinase C delta, completely prevented the stimulation of the transport rate. A lower activation of hexose uptake (19%, p<0.001) followed also treatment with Gö6976, an inhibitor of conventional protein kinases C. Finally, PD98059-mediated inhibition of the phosphorylation of ERK 1/2, a downstream mitogen-activated protein kinase (MAPK), only partially reduced the activation of glucose transport induced by simulated ischemia (31%, p<0.01), while SB203580, an inhibitor of p38 MAPK, did not exert any effect. These results indicate that stimulation of protein kinase C delta is strongly related to the up-regulation of glucose transport induced by simulated ischemia in cultured cardiomyoblasts and that conventional protein kinases C and ERK 1/2 are partially involved in the signalling pathways mediating this process.

Contribution of reactive oxygen species to the regulation of Glut1 in two hemopoietic cell lines differing in cytokine sensitivity

Glucose transport activity and its possible regulation by reactive oxygen species in two Glut1-expressing megakaryocytic cell lines, MO7e and B1647, differing in cytokine sensitivity were compared. Results show that: (1) In MO7e cells, glucose transport rate increased in response to thrombopoietin, granulocyte-macrophage colony-stimulating factor, or stem cell factor, due to a decreased Km. (2) A higher Vmax value was determined in B1647 cells, owing to the relative higher abundance of Glut1 on the plasmalemma; in these cells no change in glucose transport rate was observed on cytokine treatment. (3) The basal level of intracellular ROS was higher in B1647 than in M07e cells, where ROS production was enhanced upon cytokine exposure. (4) Basal or stimulated ROS production and Glut1 activity were significantly reduced by pretreating both cell lines with EUK-134, a superoxide dismutase and catalase mimetic. (5) In MO7e cells, EUK-134 brought back to control levels the Km values obtained on cytokine treatment, whereas in B1647 cells the antioxidant drastically reduced Vmax by decreasing the Glut1 content of the plasma membrane. Our data suggest that differences in acute regulation of glucose transport activity in the two cell lines may be related to differences in amplitude and spatial organization of ROS production.

Mitochondrial gene-knockout (rho0) cells: a versatile model for exploring the secrets of trans-plasma membrane electron transport

Plasma membrane electron transport (tPMET) pathways have been identified in all living cells, and a wide variety of tools have been used to study these processes. In our laboratory we have used the cell-impermeable tetrazolium dye WST-1, together with the mitochondrial gene knockout (rho0) cell model, to investigate one of these pathways. We have shown that growth of HL60rho0 cells is dependent on oxygen, and that these cells consume oxygen at the cell surface. Similarities in inhibition profiles between non-mitochondrial oxygen consumption and WST-1 reduction suggest that both systems share a common tPMET pathway. In support of this, oxygen was shown to compete with the intermediate electron acceptor that mediates WST-1 reduction, for reducing electrons. The observation that tPMET activity is higher in rho0 cells compared to their mitochondrially-competent counterparts was shown to be the result of competition between the mitochondrial and plasma membrane electron transport systems for intracellular reducing equivalents. Elevated rates of dye reduction appear to be mediated through increased expression of the key components of tPMET, which include the cell surface NADH oxidase, CNOX. These findings have played a critical role in shaping our current understanding of the mechanisms of this particular pathway of tPMET.

Stem cell factor and H2O2 induce GLUT1 translocation in M07e cells

This work aims to elucidate the mechanisms involved in the early activation of glucose transport in hematopoietic M07e cells by stem cell factor (SCF) and a reactive oxygen species (ROS) as H2O2. SCF and H2O2 increase Vmax for glucose transport; this enhancement is due to a higher content in GLUT1 in plasma membranes, possibly through a translocation from intracellular stores. Inhibitors of tyrosine kinases or phospholipase C (PLC) remove glucose transport enhancement and prevent translocation. The inhibitory effect of STI-571 suggests a role for c-kit tyrosine kinase on glucose transport activation not only by SCF, but also by H2O2. On the other hand, neither protein kinase C nor phosphoinositide-3-kinase appear to be involved in the acute activation of glucose transport. Our data suggest that i) in M07e cells, SCF and exogenous H2O2 elicit a short-term activation of glucose transport through a translocation of GLUT1 from intracellular stores to plasma membranes; ii) both stimuli could share at least some signaling pathways leading to glucose uptake activation, involving protein tyrosine kinases and PLC iii) H2O2 could act increasing the level of tyrosine phosphorylation through the inhibition of tyrosine phosphatases and mimicking the regulation role of endogenous ROS.

ROS production and Glut1 activity in two human megakaryocytic cell lines

Reactive oxygen species (ROS) has been increasingly recognised as intracellular messengers in signal transduction following receptor activation by a variety of bioactive peptides including growth factors, cytokines and hormones. In this study ROS production and glucose transport activity were evaluated in the growth factor dependent M07e cells and in B1647 cells, not requiring additional hematopoietic cytokines for growth: the aim was to investigate whether ROS could be involved in the regulation of Glut1-mediated glucose uptake in both cell lines. The effect of the synthetic superoxide and hydrogen peroxide scavenger EUK-134 on DOG uptake activity and intracellular ROS formation supports the concept of reactive oxygen species as signalling molecules. In order to investigate ROS generation sources, diphenyleneiodonium, an inhibitor of flavoprotein centres and apocynin, an inhibitor of NAD(P)H oxidase, were used: they inhibit both ROS production and glucose uptake activation. All these data support the hypothesis that ROS can contribute to the regulation of glucose transport, not only in M07e cells but also in B1647 cells; we could speculate that one possible source of ROS, linked somehow with Glut1 activity, can be a NAD(P)H oxidase similar to that one present in phagocytic cells.

Nonionic amphiphilic polymers derived from Tris(hydroxymethyl)-acrylamidomethane keep membrane proteins soluble and native in the absence of detergent

A new family of amphipols-amphiphilic polymers designed to form water-soluble complexes with membrane proteins-was synthesized by free-radical telomerization of Tris(hydroxymethyl)-acrylamidomethane (THAM) and derivatized THAM. Some of these polymers were found to prevent aggregation and denaturation of two model membrane proteins, bacteriorhodopsin and cytochrome b(6) f, in the absence of detergent micelles.

Recent advances in amino acid analysis by capillary electrophoresis

Amino acids are studied extensively using capillary electrophoresis. In this review we will report the different researchs which have been done in the literature since 1998. We will describe the developments of, detection methods, separations of enantiomers, the new medical applications, and amino acids in food and plants.

Synthesis and surface-active properties of glycosyl carbamates and thioureas

Several amphiphilic glycosyl carbamates, glycosyl thiocarbamates and glycosylthioureas were prepared by addition of the anomeric hydroxyl group of acetylated glycosyl derivatives to alkyl isocyanates, or by reaction of glycosyl isothiocyanates with alcohols or amines. The solubility, critical micelle concentrations and detergent efficiency for the extraction of proteins of these compounds were evaluated and compared.