1,721,006 research outputs found
Ostreopsis cf. ovata induces cytoskeletal disorganization, apoptosis, and gene expression disregulation on HeLa cells
No full textThe dinoflagellates of the genus Ostreopsis Schmidt are toxic species involved in the occurrence of massive blooms. These dinoflagellates are known to produce palytoxin and ovatoxins, which are considered amongst the most poisonous phycotoxins in the world. In this work, aqueous and methanolic extracts of one Ostreopsis cf. ovata Ionian strain were tested on the human-derived HeLa cell line, and cytotoxicity, cytoskeletal rearrangement, and apoptosis induction were recorded by morphological and molecular analysis. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test revealed high toxicity for both extracts, which activity was inhibited by ouabain, which suggests the main involvement of palytoxin-like molecules in the observed toxic effects of this strain. Overall, the effects induced by O. cf. ovata on HeLa cells were dependent on the type of adopted extracts, being both toxic, but with the methanolic extract more toxic than the aqueous one and able to induce cell death by apoptosis. This process was evidenced by both phosphatidylserine exposition and upregulation of caspase-3 gene expression. The different effect of the two extracts on cell death is indicative of their different composition and/or activity. Our findings represent the starting step for the characterization of novel bioactive molecul
Differential transcript and soluble factor patterns in macrophage/enterocyte-like monolayer co-cultures based on apical or basolateral LPS exposure
Full text linkBackground: The monolayer of intestinal epithelial cells (IECs) plays a crucial role in controlling intestinal homeostasis, also by its interaction with the immune system, via paracrine cytokine production, thus driving innate responses by tissue-resident immune cells. Here, using a co-culture model, we investigated the interactions between differentiated Caco-2 cells in monolayer and macrophages, by mimicking the cross-talk between enterocytes and immune cells during gastrointestinal (GI) tract inflammation. Methods: Caco-2 mature monolayers grown on Transwell membranes were challenged with apical or basolateral LPS. After stimulations, the enterocyte-like monolayers were transferred in co-culture with THP-1 derived macrophages. The functional impact of treatments was evaluated in terms of monolayer's permeability, expression of mRNAs related to inflammation and immune responses and analysis of immune soluble factors present in the co-culture media. Results: LPS effectively affected monolayer's permeability and induced a pro-inflammatory transcriptional program in Caco-2 monolayers. Remarkably, THP-1 derived macrophages differentially responded based on the diverse directional source of LPS, previously administered to the Caco-2 monolayers. Basolateral sensing of LPS, by Caco-2 monolayers, induced specific increase of several pro-inflammatory factors such as NF-kB1, IL-6 and IL-8, at transcript level, in macrophages, while apical sensing triggering targeted increase of IL-1β expression. Significantly, the analysis of immune factors secreted in the co-culture media suggested that paracrine interactions between enterocyte-like monolayers and macrophages are differently driven based on the basolateral vs. apical inflammation, previously triggered by LPS against the epithelial monolayer, and thus involving different immune gene networks. Conclusions: Taken together, our results suggest a framework of interactions between IECs and macrophages, depending upon the "polarized" inflammatory dysregulation
Magnetic nano-architectures intended for bone cancer treatment: physical and biological characterization
No full textCarnosine modulates the Sp1-Slc31a1/Ctr1 copper-sensing system and influences copper homeostasis in murine CNS-derived cells
No full textCarnosine (CAR) is an endogenous dipeptide physiologically present in excitable tissues, such as central nervous system (CNS) and muscle. CAR is acknowledged as a substrate involved in many homeostatic pathways and mechanisms and, due to its biochemical properties, as a molecule intertwined with the homeostasis of heavy metals such as copper (Cu). In CNS, Cu excess and dysregulation imply oxidative stress, free-radical production, and functional impairment leading to neurodegeneration. Here, we report that CAR intercepts the regulatory routes of Cu homeostasis in nervous cells and tissues. Specifically, in a murine neuron-derived cell model, i.e., the B104 neuroblastoma cells, extracellular CAR exposure up to 24 h influenced intracellular Cu entry and affected (downregulated) the key Cu-sensing system, consisting of the gene coding for the Slc31a1 transmembrane Cu importer (alias Ctr1), and the gene coding for the Cu-responsive transcription factor Sp1 (Sp1). Also, CAR exposure upregulated CAR biosynthesis (Carns1), extracellular degradation (Cndp1), and transport (Slc15a4, alias Pht1) genes and elicited CAR intracellular accumulation, contributing to the outline of functional association between CAR and Cu within the cell. Interestingly, the same gene modulation scheme acting in vitro operates in vivo in brains of mice undergoing dietary administration of CAR in drinking water for 2 wk. Overall, our findings describe for the first time a regulatory interaction between CAR and Cu pathways in CNS and indicate CAR as a novel active molecule within the network of ligands and chaperones that physiologically regulate Cu homeostasis
Bacterial challenge induces variation of the Allograft Inflammatory Factor I (AIF-1) gene expression in Paracentrotus lividus.
No full textThe interest for echinoderm immune defence system is steadily increasing due to their phylogenetic, ecological, biotechnological and economical relevance. Their basal position within the deuterostome lineage makes the analysis of their defense mechanisms highly relevant to understand the evolution of the deuterostome immune system. Suggestions derive from the analysis of the immune genes and of their products, such as cytokines. The Allograft Inflammatory Factor-1 (AIF1), a calcium-binding cytokine and a key regulator of the immune response, play an important role during inflammation in Vertebrata. Recent literature evidences that proteins of the AIF1 superfamily are present in several phylogenetically distant species, all showing high similarity at the primary protein sequence level. In the present work, we report on the immune response of the sea urchin Paracentrotus lividus after a G+ bacteria challenge. The constitutive expression of AIF-1-like protein has been evidenced in P. lividus coelomocytes where the mRNA levels were found to be up-regulated at 24 h post-bacterial injection
Systematic Evaluation of the Mesh Size of Poly(ethylene glycol)-based Hydrogels for Biomedical Applications
No full textPoly(ethylene glycol) (PEG) hydrogels are one of the most widely utilized biomaterial systems, thanks to their intrinsic resistance to protein adsorption and the ability to be covalently linked to multiple functional moieties. This opens a wide range of design options for the synthesis of substrates with tunable chemistry and bioactivity. Moreover, the hydrogel mesh size can be finely controlled to regulate the molecular trafficking within the polymer matrix. The primary objective of this work was to explore the mesh size of poly(ethylene glycol) diacrylate (PEGDA)-based hydrogels obtained by photo- crosslinking. Aqueous solutions differing for polymer concentration and type of photoinitiator were crosslinked by ultraviolet (UV) expo- sure for different time lengths. Free swelling and uniaxial compression measurements were performed to evaluate the hydrogel mesh size, based on classical theoretical models of swelling and rubber elasticity. The calculated values of mesh size were then experimentally validated by protein diffusion studies. Further aim of this work was to assess the gradual increase of the mesh size resulting from hydrolytic degradation, upon incubation at 37°C for 10 weeks. The experimental results showed that, for the hydrogel formulations tested, the mesh size could be reliably estimated by both swelling and mechanical measurements. Remarkably, the evaluation of the mesh size following hydrolysis al- lowed detection of significant differences in the degradation rate of the samples, while providing pivotal information on the dynamic change of their diffusive properties. Such a systematic evaluation of the mesh size allows the careful design of PEG-based hydrogels for medium to long- term biomedical applications
Di- and tripeptide transport in vertebrates: the contribution of teleost fish models
No full textSolute Carrier 15 (SLC15) family, alias H(+)-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates
Transforming growth factor-β1 induces matrix metalloproteinase and cell migration in Schwann cells.
No full textThis study aimed to evaluate the effect of TGF-β1 on RSC96 Schwann cell migration and to study its intracellular transduction pathways.
We found that TGF-β1 induced the activation of key signaling molecules involved in non-Smad (Akt and MAPK) and focal adhesion signaling pathways (FAK and Src) that cooperatively regulated the process of RSC96 cells migration together with MMP-2 and MMP-9 upregulation.
These findings indicate a regulatory pathway of TGF-β1 in MMP-9/-2 expression which may be significant in regulating Schwann cell migration and physiology in peripheral nervous sytem injury
Functional Characterization of a Novel Protocol for Encapsulation of Pancreatic Islets within a Conformal Layer of Poly(Ethylene Glycol)-Based Hydrogel
No full textType 1 Diabetes is an autoimmune disease with no currently available therapies for a definitive reversal of the pathological phe- notype. Among available therapies, pancreatic islet transplantation is a promising strategy, although the requirement of life-long systemic immunosuppression and the limited number of islet donors reduces its widespread application. In this context, islet encapsulation is a promising strategy to create a physical barrier to prevent islet de- struction by the recipient immune system. Furthermore, the encap- sulation material can be exploited as a substrate to conjugate immunomodulatory antibodies or bioactive molecules in order to enhance the immunoprotection activity and to drive targeted im- munosuppression. In this study we developed a protocol for coating murine islets with a conformal layer of poly(ethylene glycol) (PEG)- based hydrogel by employing a photopolymerization method that leads to single islet encapsulation and provides a suitable substrate for targeted functionalization. To validate the biocompatibility of our approach, we assessed encapsulated islet viability and functionality in vitro, and we analysed possible gene expression variations. Our encapsulation protocol preserved islet viability and did not affect significantly expression of apoptotic and hypoxic marker genes. The physiological responsiveness of encapsulated islets to glucose- stimulated insulin secretion was confirmed both at mRNA and pro- tein level. Moreover, effects of the coating on islet architecture were investigated by analysing cytoskeletal morphology and expression of cell-cell and cell-matrix interaction marker genes, observing no substantial differences between encapsulated and control islets. Concluding, our encapsulation protocol provides a safe and bio- compatible approach to encapsulate pancreatic islets, thus suitable for targeted functionalization
Chitosan-based scaffolds exhibit modular features induced by magnetic nanoparticles and L-arginine amino acid
No full textLarge bone or osteochondral defects still need new
approaches to ameliorate the regeneration process. The
integration of magnetic nanoparticles into synthetic/natural
scaffold formulations, could lead to obtain a suitable, responsive
“on demand” tool able to guide the regeneration process. The
aim of this work was the design and characterization of
chitosan-based scaffolds containing dextran-grafted maghemite
(DM) with modular mechano-structural and biomimetic
properties implemented by the presence of a bioactive agent
such the L-arginine amino acid. Both components can act as
modulators of the scaffold features and, at the same time, the
simultaneous presence of MNPs and L-Arg can be exploited to
induce variations with respect to the cytocompatibility
responses
- …
