An Update on Graphene-Based Nanomaterials for Neural Growth and Central Nervous System Regeneration.

Thanks to their reduced size, great surface area, and capacity to interact with cells and tissues, nanomaterials present some attractive biological and chemical characteristics with potential uses in the field of biomedical applications. In this context, graphene and its chemical derivatives have been extensively used in many biomedical research areas from drug delivery to bioelectronics and tissue engineering. Graphene-based nanomaterials show excellent optical, mechanical, and biological properties. They can be used as a substrate in the field of tissue engineering due to their conductivity, allowing to study, and educate neural connections, and guide neural growth and differentiation; thus, graphene-based nanomaterials represent an emerging aspect in regenerative medicine. Moreover, there is now an urgent need to develop multifunctional and functionalized nanomaterials able to arrive at neuronal cells through the blood-brain barrier, to manage a specific drug delivery system. In this review, we will focus on the recent applications of graphene-based nanomaterials in vitro and in vivo, also combining graphene with other smart materials to achieve the best benefits in the fields of nervous tissue engineering and neural regenerative medicine. We will then highlight the potential use of these graphene-based materials to construct graphene 3D scaffolds able to stimulate neural growth and regeneration in vivo for clinical applications.

Effects of diclofenac on the swimming behavior and antioxidant enzyme activities of the freshwater interstitial crustacean Bryocamptus pygmaeus (Crustacea, Harpacticoida).

Diclofenac (DCF) is one of the most widespread pharmaceutical compounds found in freshwaters as a pseudo-persistent pollutant due to its continuous release from point and diffuse sources, being its removal in Wastewater Treatment Plants incomplete. Moreover, DCF is particularly persistent in interstitial habitats and potentially toxic for the species that spend their whole life cycle among the same sediment grains. This study is aimed at offering a first contribution to the assessment of DCF effects on freshwater invertebrate species living in the interstitial habitats of springs, rivers, lakes and groundwaters. The Crustacea Copepoda are one of the main components of the freshwater interstitial communities, with the primacy taken by the worm-like and small-sized harpacticoids. A sub-lethal concentration of 50 µg L-1 DCF significantly affected six out of the eight behavior parameters of the burrower/interstitial crustacean harpacticoid Bryocamptus pygmaeus recorded by video tracking analysis. DCF exposure reduced swimming speed, swimming activity, exploration ability and thigmotaxis, and increased swimming path tortuosity. The biochemical approach revealed a reduced level of the mitochondrial superoxide dismutase 2 in individuals exposed to DCF. It could be explained by a decline in mitochondrial performance or by a reduced number of functional mitochondria. Since mitochondrial dysfunction may determine ATP reduction, it comes that less energy is produced for maintaining the cell functions of the DCF-exposed individuals. In addition, the increasing energy demand for the detoxification process further contributes to decrease the total energetic budget allocated for other physiological activities. These observations can explain the changes we have observed in the swimming behavior of the copepod B. pygmaeus.

Environmentally relevant concentrations of triclocarban affect morphological traits and melanogenesis in zebrafish larvae.

Human activity is responsible for producing several chemical compounds, which contaminate the aquatic environment and adversely influence the survival of aquatic species and indirectly human health. Triclocarban (TCC) belongs to the category of emerging pollutants and its presence in aquatic environment is justified by its wide use as antimicrobial agent in personal care products. The concern about this chemical is due to the risk of persistence in water and soils and bioaccumulation, which contributes to human exposition through the contaminated food consumption. The present study evaluated the developmental toxicity of TCC in zebrafish early-life stages starting with the assessment of acute toxicity and then focusing on the integrative analyses of the observed phenotype on zebrafish development. For this purpose, lethal and sublethal alterations of zebrafish embryos were investigated by the Fish Embryo Acute Toxicity Tests (FET tests). Subsequently, two concentrations of TCC were used to investigate the morphometric features and defects in larvae developmental pigmentation: an environmentally relevant (5µg/L) and toxicological (50µg/L), derived from the No Observed Effect Concentration (NOEC) value concentration. Furthermore, the expression levels of a key transcription factor for melanocyte differentiation and melanin syntheses, such as mitfa (microphthalmia-associated transcription factor) and tyr (tyrosinase) and its activity, were evaluated.

Inflammatory Bowel Disease: New Insights into the Interplay between Environmental Factors and PPARγ.

The pathophysiological processes of inflammatory bowel diseases (IBDs), i.e., Crohn's disease (CD) and ulcerative colitis (UC), are still not completely understood. The exact etiology remains unknown, but it is well established that the pathogenesis of the inflammatory lesions is due to a dysregulation of the gut immune system resulting in over-production of pro-inflammatory cytokines. Increasing evidence underlines the involvement of both environmental and genetic factors. Regarding the environment, the microbiota seems to play a crucial role. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors that exert pleiotropic effects on glucose homeostasis, lipid metabolism, inflammatory/immune processes, cell proliferation, and fibrosis. Furthermore, PPARs modulate interactions with several environmental factors, including microbiota. A significantly impaired PPARγ expression was observed in UC patients' colonic epithelial cells, suggesting that the disruption of PPARγ signaling may represent a critical step of the IBD pathogenesis. This paper will focus on the role of PPARγ in the interaction between environmental factors and IBD, and it will analyze the most suitable in vitro and in vivo models available to better study these relationships.

Biocompatibility of composites based on chitosan, apatite, and graphene oxide for tissue applications.

Novel two-dimensional films and three-dimensional (3D) scaffolds based on chitosan (CHI), apatite (Ap), and graphene oxide (GO) were developed by an in situ synthesis in which self-assembly process was conducted to direct partial reduction of GO by CHI in acidic medium. Physical-chemical characterization was carried out by optical microscopy, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. In vitro biological studies using murine fibroblast (MC3T3) and human neuroblastoma (SH-SY5Y) cell lines were also performed. Cell growth and adherence on composites was also checked using SEM. Live and death staining by confocal microscope and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium of the samples were investigated. The results confirmed the incorporation of both Ap and GO sheets, into CHI polymeric matrix. Furthermore, it was confirmed a physical integration between inorganic Ap and organic CHI and strong chemical interaction between CHI and GO in the obtained composites. SH-SY5Y cell line showed preferential adherence on CHI/GO films surface while MC3T3 cell line displayed a good compatibility for all 3D scaffolds. This study confirms the biocompatibility of materials based on CHI, Ap, and GO for future tissues applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1585-1594, 2018.

Targeted therapy of human glioblastoma via delivery of a toxin through a peptide directed to cell surface nucleolin.

Targeted anticancer therapies demand discovery of new cellular targets to be exploited for the delivery of toxic molecules and drugs. In this perspective, in the last few years, nucleolin has been identified as an interesting surface marker to be used for the therapy of glioblastoma. In this study, we investigated whether a synthetic antagonist of cell-surface nucleolin known as N6L, previously reported to decrease both tumor growth and tumor angiogenesis in several cancer cell lines, including glioblastoma cells, as well as endothelial cells proliferation, could be exploited to deliver a protein toxin (saporin) to glioblastoma cells. The pseudopeptide N6L cross-linked to saporin-S6 induced internalization of the toxin inside glioblastoma cancer cells. Our results in vitro demonstrated the effectiveness of this conjugate in inducing cell death, with an ID50 four orders of magnitude lower than that observed for free N6L. Furthermore, the preliminary in vivo study demonstrated efficiency in reducing the tumor mass in an orthotopic mouse model of glioblastoma.

PPARα Antagonist AA452 Triggers Metabolic Reprogramming and Increases Sensitivity to Radiation Therapy in Human Glioblastoma Primary Cells.

Glioblastoma (GB) is the most common cancer in the brain and with an increasing incidence. Despite major advances in the field, there is no curative therapy for GB to date. Many solid tumors, including GB, experienced metabolic reprogramming in order to sustain uncontrolled proliferation, hypoxic conditions, and angiogenesis. PPARs, member of the steroid hormone receptor superfamily, are particularly involved in the control of energetic metabolism, particularly lipid metabolism, which has been reported deregulated in gliomas. PPARα was previously indicated by us as a potential therapeutic target for this neoplasm, due to the malignancy grade dependency of its expression, being particularly abundant in GB. In this work, we used a new PPARα antagonist on patient-derived GB primary cells, with particular focus on the effects on lipid metabolism and response to radiotherapy. The results obtained demonstrated that blocking PPARα results in cell death induction, increase of radiosensitivity, and decrease of migration. Therefore, AA452 is proposed as a new adjuvant for the gold standard therapies for GB, opening the possibility for preclinical and clinical trials for this class of compounds. J. Cell. Physiol. 232: 1458-1466, 2017. © 2016 Wiley Periodicals, Inc.

A peroxiredoxin-based proteinaceous scaffold for the growth and differentiation of neuronal cells and tumour stem cells in the absence of prodifferentiation agents.

The use of nanoscale materials in the design of scaffolds for CNS tissue is increasing, due to their ability to promote cell adhesion, to mimic an extracellular matrix microenvironment and to interact with neuronal membranes. In this framework, one of the major challenges when using undifferentiated neural cells is how to control the differentiation process. Here we report the characterization of a scaffold based on the self-assembled nanotubes of a mutant of the protein peroxiredoxin (from Schistosoma mansoni or Bos taurus), which allows the growth and differentiation of a model neuronal cell line (SHSY5Y). The results obtained demonstrate that SHSY5Y cells grow without any sign of toxicity and develop a neuronal phenotype, as shown by the expression of neuronal differentiation markers, without the use of any differentiation supplement, even in the presence of serum. The prodifferentiation effect is demonstrated to be dependent on the formation of the protein nanotube, since a wild-type (WT) form of the peroxiredoxin from Schistosoma mansoni does not induce any differentiation. The protein scaffold was also able to induce the spread of glioblastoma cancer stem cells growing in neurospheres and allowing the acquisition of a neuron-like morphology, as well as of immature rat cortical neurons. This protein used here as coating agent may be suggested for the development of scaffolds for tissue regeneration or anti-tumour devices. Copyright © 2016 John Wiley & Sons, Ltd.

Lactoferrin from Milk: Nutraceutical and Pharmacological Properties.

Lactoferrin is an iron-binding protein present in large quantities in colostrum and in breast milk, in external secretions and in polymorphonuclear leukocytes. Lactoferrin's main function is non-immune protection. Among several protective activities shown by lactoferrin, those displayed by orally administered lactoferrin are: (i) antimicrobial activity, which has been presumed due to iron deprivation, but more recently attributed also to a specific interaction with the bacterial cell wall and extended to viruses and parasites; (ii) immunomodulatory activity, with a direct effect on the development of the immune system in the newborn, together with a specific antinflammatory effects; (iii) a more recently discovered anticancer activity. It is worth noting that most of the protective activities of lactoferrin have been found, sometimes to a greater extent, also in peptides derived from limited proteolysis of lactoferrin that could be generated after lactoferrin ingestion. Lactoferrin could therefore be considered an ideal nutraceutic product because of its relatively cheap production from bovine milk and of its widely recognized tolerance after ingestion, along with its well demonstrated protective activities. The most important protective activities shown by orally administered bovine lactoferrin are reviewed in this article.