23 research outputs found

    Involvement of ionic channels in chemically-induced neurotoxicity: examples of different molecular mechanisms

    Get PDF
    Neurotoxicity is defined as \u201can adverse change in the structure or function of the nervous system that results from exposure to a chemical, biological or physical agent". lonic channels, transporters, receptors for neurotransmitters and neurohormones are the main modulators of neuronal activity. It is therefore to be expected that the interfering with these proteins induces significant and potentially damaging effects in these tightly regulated and highly responsive cells. The present research project has been focused on the study of the role of specific ionic channels and the main mechanisms involved regarding two cases of neurotoxicity, which were widely documented but not completely understood: 1) the potential neurotoxicity induced by SiO2 NP and 2) the one induced by OHP. This issue has been addressed by means of an integrated approach that combine electrophysiological recordings both at single cell level by using the patch clamp technique, and at population level by using multielectrode arrays (MEAs), as well as quantitative real-time polymerase chain reaction (qRT-PCR) and/or RNAseq for a trascriptome screening. Members of TRP channel family (TRPA1, TRPV1, TRPV4), two pore domain K+ (K2P) channel family, as well as connexins and pannexin-like channels, are the major components of the responses by SiO2 NP and OHP. In conclusion, the information presented here may be valuable, particularly for contributing to current knowledge on this subject mainly regarding cells of the nervous system, as some evidence and mechanistic suggestions are provided

    Nanoparticles and potential neurotoxicity: focus on molecular mechanisms

    Get PDF
    The last decades have seen an explosive increase in the development of nanoparticles and in their use in consumer, industrial and medical applications. Their fast diffusion has also raised widespread concern about the potential toxic effects on living organisms, including humans: at the nanoscale, they can interact with subcellular components such as membranes, proteins, lipids, nucleic acids, thus inducing unpredicted functional perturbations in cells and tissues. The nervous tissue is a particular sensitive target, because its cellular components (mainly neurons and glial cells) are tightly regulated and metabolically exigent biological entities. While the literature on the potential toxicity of nanoparticles has grown in parallel with their utilization, the available data on neurotoxicity are less abundant. In particular, information on the neuronal molecular targets of nanoparticles is still largely incomplete. A better understanding of this issue is highly relevant for the rational and controlled design of nanoparticles, both for their general utilization and more specifically for their use in the promising field of nanoneuromedicine. In this review, we will discuss the available information on the mechanisms involved in the interaction between nanoobjects and cells of the nervous system, focusing on the known molecular actors, both at the plasma membrane and in intracellular compartments

    Tumor derived Microvesicles enhance cross-processing ability of clinical grade Dendritic Cells

    Get PDF
    Tumor cells release extracellular microvesicles (MVs) in the microenvironment to deliver biological signals to neighbouring cells as well as to cells in distant tissues. Tumor-derived MVs appear to play contradictory role promoting both immunosuppression and tumor growth and both evoking tumor specific immune response. Recent evidences indicate that tumor-derived MVs can positively impact Dendritic Cells (DCs) immunogenicity by reprogramming DC antigen processing machinery and intracellular signaling pathways, thus promoting anti-tumor response. DCs are considered pivot cells of the immune system due to their exclusive ability to coordinate the innate and acquired immune responses, cross-present exogenous antigens and prime na√Įve T cells. DCs are required for the induction and maintenance of long-lasting anti-tumor immunity and their exploitation has been extensively investigated for the design of anti-tumor vaccines. However, the clinical grade culture conditions that are required to generate DCs for therapeutic use can strongly affect their functions. Here, we investigated the immunomodulatory impact of MVs carrying the MUC1 tumor glycoantigen (MVsMUC1) as immunogen formulation on clinical grade DCs grown in X-VIVO 15 (X-DCs). Results indicated that X-DCs displayed reduced performance of the antigen processing machinery in term of diminished phagocytosis and acidification of the phagosomal compartment suggesting an altered immunogenicity of clinical grade DCs. Pulsing DCs with MVsMUC1 restored phagosomal alkalinization, triggering ROS increase. This was not observed when a soluble MUC1 protein was employed (rMUC1). Concurrently, MVsMUC1 internalization by X-DCs allowed MUC1 cross-processing. Most importantly, MVsMUC1 pulsed DCs activated IFNő≥ response mediated by MUC1 specific CD8+ T cells. These results strongly support the employment of tumor-derived MVs as immunogen platforms for the implementation of DC-based vaccine

    Tumor-Derived Microvesicles Enhance Cross-Processing Ability of Clinical Grade Dendritic Cells

    Get PDF
    Tumor cells release extracellular microvesicles (MVs) in the microenvironment to deliver biological signals to neighboring cells as well as to cells in distant tissues. Tumor-derived MVs appear to play contradictory role promoting both immunosuppression and tumor growth and both evoking tumor specific immune response. Recent evidences indicate that tumor-derived MVs can positively impact Dendritic Cells (DCs) immunogenicity by reprogramming DC antigen processing machinery and intracellular signaling pathways, thus promoting anti-tumor response. DCs are considered pivot cells of the immune system due to their exclusive ability to coordinate the innate and acquired immune responses, cross-present exogenous antigens, and prime na√Įve T cells. DCs are required for the induction and maintenance of long-lasting anti-tumor immunity and their exploitation has been extensively investigated for the design of anti-tumor vaccines. However, the clinical grade culture conditions that are required to generate DCs for therapeutic use can strongly affect their functions. Here, we investigated the immunomodulatory impact of MVs carrying the MUC1 tumor glycoantigen (MVsMUC1) as immunogen formulation on clinical grade DCs grown in X-VIVO 15 (X-DCs). Results indicated that X-DCs displayed reduced performance of the antigen processing machinery in term of diminished phagocytosis and acidification of the phagosomal compartment suggesting an altered immunogenicity of clinical grade DCs. Pulsing DCs with MVsMUC1 restored phagosomal alkalinization, triggering ROS increase. This was not observed when a soluble MUC1 protein was employed (rMUC1). Concurrently, MVsMUC1 internalization by X-DCs allowed MUC1 cross-processing. Most importantly, MVsMUC1 pulsed DCs activated IFNő≥ response mediated by MUC1 specific CD8+ T cells. These results strongly support the employment of tumor-derived MVs as immunogen platforms for the implementation of DC-based vaccines

    Valorization of olive mill wastewaters as a renewable resource for the biological production of polyhydroxyalkanoates

    No full text
    An innovative biotechnological anaerobic-aerobic integrated three-stage process for the production of polyhydroxyalkanoates (PHAs) is being studied. A low-cost renewable row material such as the liquid waste resulting from olive oil producing processes (olive mill wastewater, OMW) is employed to feed the first anaerobic step, by which obtaining an effluent rich in volatile fatty acids (VFAs). Four anaerobic packed-bed biofilm reactors filled with granular active carbon (GAC) or ceramic cubes (VS) were developed and employed in batch and continuous conditions in the OMW acidogenic fermentation. The effect on the process of temperature and organic loading rates were studied. Higher COD conversion in VFAs were obtained in the reactor filled with VS. In the second aerobic process stage, a sequencing batch reactor (SBR) is fed with the anaerobic effluent, with the aim of selecting microbial populations able to store PHAs through the metabolic conversion of VFAs. A SBR inoculated with an activated sludge was fed with a synthetic VFA mixture by different pH conditions. The highest substrate removal and polymer production rates were obtained at pH 8.5. The selected microflora is finally employed in a third aerobic batch stage fed with the VFA-rich anaerobic effluent. A batch experiment was carried out at pH 8.5. PHAs were produced at a rate of approximately 350 mgCOD/gCOD/h, with a storage yield of 45% (as COD). The produced polymer was a P(HB-HV) co-polymer, with 13% (mol/mol) HV content

    Exploiting olive oil mill effluents as a renewable resource for production of biodegradable polymers through an anaerobic-aerobic process

    No full text
    This study describes the performance of a three-stage process for the bioproduction of polyhydroxyalkanoates (PHAs) from olive oil mill wastewaters (OMWs). In the first stage OMWs were anaerobically fermented, in a packed bed biofilm reactor (PBBR), to a mixture of volatile fatty acids (VFAs) (up to 32 % of the overall COD), that are the most suitable substrates for PHAs production. This VFA-rich effluent was fed to the second stage of the process, performed in a fully-aerobic Sequencing Batch Reactor (SBR), in which mixed cultures able to store PHAs were selected. Rates and yields of PHA storage were similar to those obtained with a synthetic mixture of VFAs, indicating the non-inhibitory nature of the fermented OMWs. Finally, the storage response of the selected consortia was exploited in the third aerobic stage, which was operated, in batch conditions, at different loads (from 1 to about 9 times the usual SBR load) in order to maximize the polymer content in the biomass. The overall storage yield on the fermented OMWs was about 0.36 COD/COD, with about half of the PHAs being produced from substrates other than VFAs, such as alcohols. Overall, the proposed process is promising for the simultaneous treatment of OMWs and their valorization as a renewable resource for PHA production

    Effect of pH on the production of bacterial polyhydroxyalkanoates by mixed cultures enriched under periodic feeding

    No full text
    This research investigated the effect of pH on polyhydroxyalkanoate (PHA) production by mixed cultures enriched in a sequencing batch reactor (SBR) starting from activated sludge. The enrichment was performed with a mixture of acetic (85% on COD basis) and propionic (15%) acid, at an organic load rate of 8.5 gCOD/L/day over the range of pH from 7.5 to 9.5. The enriched cultures were all able to store the copolymer poly(3-hydroxybutyrate/3-hydroxyvalerate). Higher polymer production rates and yields (389 mg PHA (as COD)/g non-polymer biomass (as COD)/h and 0.53 COD/COD, respectively) were observed when the pH in the SBR was controlled at 7.5, with Lampropedia hyalina as the dominant bacterial species of the microbial community. PHA composition was also strongly affected by the pH. Indeed, batch tests showed that hydroxyvalerate (HV) content in the copolymer increased with increasing pH up to about 48% (mol/mol) at pH 9.5. Interestingly, the possibility of enhancing the HV content was also verified by performing batch tests at a more alkaline pH value than that in the SBR. In conclusion, this paper suggests that pH control is a main tool to tune HV content in the PHA, regardless of the feed composition

    Effect of pH on the production of bacterial polyhydroxyalkanoates by mixed cultures enriched under periodic feeding

    No full text
    This research investigated the effect of pH on polyhydroxyalkanoate (PHA) production by mixed cultures enriched in a sequencing batch reactor (SBR) starting from activated sludge. The enrichment was performed with a mixture of acetic (85% on COD basis) and propionic (15%) acid, at an organic load rate of 8.5 gCOD/L/day over the range of pH from 7.5 to 9.5. The enriched cultures were all able to store the copolymer poly(3-hydroxybutyrate/3-hydroxyvalerate). Higher polymer production rates and yields (389 mg PHA (as COD)/g non-polymer biomass (as COD)/h and 0.53 COD/COD, respectively) were observed when the pH in the SBR was controlled at 7.5, with Lampropedia hyalina as the dominant bacterial species of the microbial community. PHA composition was also strongly affected by the pH. Indeed, batch tests showed that hydroxyvalerate (HV) content in the copolymer increased with increasing pH up to about 48% (mol/mol) at pH 9.5. Interestingly, the possibility of enhancing the HV content was also verified by performing batch tests at a more alkaline pH value than that in the SBR. In conclusion, this paper suggests that pH control is a main tool to tune HV content in the PHA, regardless of the feed composition

    P2X Purinergic Receptors Are Multisensory Detectors for Micro-Environmental Stimuli That Control Migration of Tumoral Endothelium

    Get PDF
    SIMPLE SUMMARY: Extracellular ATP is highly concentrated in tumor stroma. In this study, we investigated the effects of the synthetic ATP analog Benzoylbenzoyl-ATP, 2‚Ä≤(3‚Ä≤)-O-(4-Benzoylbenzoyl)adenosine 5‚Ä≤-triphosphate (BzATP), an agonist for P2X receptors, on tumor-derived endothelial cells (TEC) obtained from three different human tumors (breast, kidney and prostate carcinomas, respectively, BTEC, RTEC and PTEC). Treatment with high BzATP concentrations (100 ¬ĶM) significantly reduced migration of all TEC types, resulting ineffective on human normal microvascular endothelium (HMEC); intriguingly, both the functional effect and associated calcium signals are sensitive to some key biological parameters of tumor stroma that include pH, Ca(2+) and Zn(2+). The lack of calcium signals selectively observed in PTEC, in which BzATP still retains its functional effect, suggests variability of intracellular signaling among TEC. These findings provide novel insights into the role of extracellular ATP as a multisensory regulator of migratory potential in tumoral endothelium. ABSTRACT: The tumoral microenvironment often displays peculiar features, including accumulation of extracellular ATP, hypoxia, low pH-acidosis, as well as an imbalance in zinc (Zn(2+)) and calcium (Ca(2+)). We previously reported the ability of some purinergic agonists to exert an anti-migratory activity on tumor-derived human endothelial cells (TEC) only when applied at a high concentration. They also trigger calcium signals associated with release from intracellular stores and calcium entry from the external medium. Here, we provide evidence that high concentrations of BzATP (100 ¬ĶM), a potent agonist of P2X receptors, decrease migration in TEC from different tumors, but not in normal microvascular ECs (HMEC). The same agonist evokes a calcium increase in TEC from the breast and kidney, as well as in HMEC, but not in TEC from the prostate, suggesting that the intracellular pathways responsible for the P2X-induced impairment of TEC migration could vary among different tumors. The calcium signal is mainly due to a long-lasting calcium entry from outside and is strictly dependent on the presence of the receptor occupancy. Low pH, as well as high extracellular Zn(2+) and Ca(2+), interfere with the response, a distinctive feature typically found in some P2X purinergic receptors. This study reveals that a BzATP-sensitive pathway impairs the migration of endothelial cells from different tumors through mechanisms finely tuned by environmental factors
    corecore