Carla Distasi - Academia.edu (original) (raw)

Papers by Carla Distasi

AIMS molecular science, 2018

The last decades have seen an explosive increase in the development of nanoparticles and in their... more 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.

Biochimica et biophysica acta. Molecular cell research, Jun 1, 2002

The electrical responses elicited by the muscarinic cholinergic pathway have been studied in cult... more The electrical responses elicited by the muscarinic cholinergic pathway have been studied in cultured embryonic chick ciliary ganglion (CG) neurons. Neurons obtained from E7-E8 ganglia were maintained in serum-free medium for 1 to 3 days. Stimulation with 50 AM muscarine induced depolarizing responses in about 30% of the cells tested. In voltage clamp experiments at a holding potential of À 50 mV, an inward current could be recorded in the same percentage of cells in response to muscarinic stimulation. In single channel experiments, with standard physiological solution in the pipette, muscarine transiently activated an inward conducting channel. Cell-attached recordings with 100 mM CaCl 2 in the pipette provided evidence that muscarinic agonists can activate a cationic calcium-permeable channel. Two main conductance levels could be detected, of 2.3 F 0.6 and 5.6 F 0.6 pS, respectively. In excised patches, addition of 5-20 AM inositol 1,4,5trisphosphate (InsP 3) to the bath reactivated a channel that could be blocked by heparin and whose characteristics were very similar to those of the channel seen in response to muscarinic stimulation. A channel with similar properties has been previously shown to be activated by basic fibroblast growth factor (bFGF) and InsP 3 in the same preparation.

Journal of Neurochemistry, Jan 19, 2011

Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and m... more Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and migrate in association with olfactory nerves (vomeronasal and terminal) to enter into the forebrain and reach their final destinations (Schwanzel-Fukuda and Pfaff 1989; Wray et al. 1989). The mechanisms underlying the establishment of the migration route and the movement of GnRH neurons are thought to involve different classes of molecules (for a review, see Tobet and Schwarting 2006). First of all, it is likely that transcriptional programs regulate the capacity and timing of GnRH neurons to migrate (Tobet and Schwarting 2006; Zaninetti et al. 2008; Orso et al. 2009). Secondly, it has been shown that a cohort of other pathways, including neurotransmitters, adhesion molecules, cell-cell interaction proteins, participate in the coordination of this migratory behaviour (Tobet and Schwarting 2006). It is likely that many of these molecules are necessary to generate gradients of attractant or to decode such gradients in the migrating GnRH-secreting neuron. Calcium is a universal signal, and its capacity to encode intracellular messages via spatial, temporal and amplitude characteristics allows it to participate in most cellular events, from egg fertilization to cell death, from neurotransmitter release to post-synaptic responses (Berridge 2001). In this view, it is not surprising that it has been heavily involved in neuronal motility, including migration (Zheng and Poo 2007). In GnRH neurons, it has been shown that calcium entry via N-type channels is essential for migration to occur (Toba et al. 2005). Furthermore, in a distinct setting, we have previously shown that the Ca 2+ /calcineurin/nuclear factor of activated T-cells pathway is important to prime neurons for migration at the transcriptional level (Zaninetti et al. 2008).

Scientific Reports, Feb 9, 2018

Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications,... more Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications, and particularly in the field of nanomedicine, thanks to the high biocompatibility of this material. For their optimal and controlled use, the understanding of the mechanisms elicited by their interaction with the biological target is a prerequisite, especially when dealing with cells particularly vulnerable to environmental stimuli like neurons. Here we have combined different electrophysiological approaches (both at the single cell and at the population level) with a genomic screening in order to analyze, in GT1-7 neuroendocrine cells, the impact of SiO 2 NPs (50 ± 3 nm in diameter) on electrical activity and gene expression, providing a detailed analysis of the impact of a nanoparticle on neuronal excitability. We find that 20 µg mL −1 NPs induce depolarization of the membrane potential, with a modulation of the firing of action potentials. Recordings of electrical activity with multielectrode arrays provide further evidence that the NPs evoke a temporary increase in firing frequency, without affecting the functional behavior on a time scale of hours. Finally, NPs incubation up to 24 hours does not induce any change in gene expression. The fast development of nanoparticles (NPs) designed and engineered to be employed as tools for targeting to specific cells and tissues and for drug delivery has opened an entire new field in both basic science and medical applications. A preliminary, albeit essential, phase was devoted at addressing the concerns about their potential toxicity in vitro and, more relevantly, in vivo. A huge amount of papers 1-3 has evidenced the parameters (size, concentration, surface properties, etc.) that can determine the presence or absence of toxic effects, thus providing the rational background for designing safe and biocompatible nanotools. The next step is to switch the focus on the more subtle effects that can arise from a prolonged presence of NPs in contact with cells, and to understand the mechanisms that underlie the interaction between objects at the nanoscale and their cellular and molecular targets. This task is particularly relevant when the target is represented by single nerve cells or by complex neuronal networks. Engineered silica NPs have encountered a rapid diffusion in several applications in the last decade 4 , specifically in nanomedicine, thanks to the high biocompatibility of this material 5. We have reported that amorphous 50 nm SiO 2 NPs can be made fluorescent by hybridization with cyanine dyes and can be safely incorporated into neurons 6 and other cell types 7. In a previous paper, we have shown that 50 nm SiO 2 NPs, at non-toxic doses, elicit increases in the intracellular calcium concentration, [Ca 2+ ] i , in a neuroendocrine cell line, GT1-7 cells 8. These signals are fully dependent on calcium influx, carried through different types of calcium permeable channels, and are completely reversible even in the continuous presence of NPs. A few other papers 3,9-11 have reported that NPs of different composition can elicit changes in neuronal [Ca 2+ ] i. This is a relevant topic, since perturbations of

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2020

Bioluminescence detection requires single-photon sensitivity, extremely low detection limits and ... more Bioluminescence detection requires single-photon sensitivity, extremely low detection limits and wide dynamic range. Such performances were traditionally assured by photomultiplier-tubes based systems. However, development of novel applications and industrialisation call for the introduction of more robust, compact and scalable devices. Silicon photomultipliers were recently put forward as the alternative to phototubes for a new generation of flexible and user friendly instruments. In this article, the figures of merit of a silicon-photomultiplier based system relying on a compact, low cost system are investigated. Possible implementations are proposed and a proof-of-principle bioluminescence measurement is performed.

Scientific Reports, Mar 9, 2023

Cancers

The tumoral microenvironment often displays peculiar features, including accumulation of extracel... more The tumoral microenvironment often displays peculiar features, including accumulation of extracellular ATP, hypoxia, low pH-acidosis, as well as an imbalance in zinc (Zn2+) and calcium (Ca2+). 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 µM), 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 ...

Neurosignals, 2005

In a neuronal subpopulation, AA at the same concentration was also able to elicit calcium release... more In a neuronal subpopulation, AA at the same concentration was also able to elicit calcium release from thapsigargin-sensitive intracellular stores; we provide evidence that cytochrome P450 epoxygenase is involved in this process.

Journal of Neurochemistry, 2011

Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and m... more Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and migrate in association with olfactory nerves (vomeronasal and terminal) to enter into the forebrain and reach their final destinations (Schwanzel-Fukuda and Pfaff 1989; Wray et al. 1989). The mechanisms underlying the establishment of the migration route and the movement of GnRH neurons are thought to involve different classes of molecules (for a review, see Tobet and Schwarting 2006). First of all, it is likely that transcriptional programs regulate the capacity and timing of GnRH neurons to migrate (Tobet and Schwarting 2006; Zaninetti et al. 2008; Orso et al. 2009). Secondly, it has been shown that a cohort of other pathways, including neurotransmitters, adhesion molecules, cell-cell interaction proteins, participate in the coordination of this migratory behaviour (Tobet and Schwarting 2006). It is likely that many of these molecules are necessary to generate gradients of attractant or to decode such gradients in the migrating GnRH-secreting neuron. Calcium is a universal signal, and its capacity to encode intracellular messages via spatial, temporal and amplitude characteristics allows it to participate in most cellular events, from egg fertilization to cell death, from neurotransmitter release to post-synaptic responses (Berridge 2001). In this view, it is not surprising that it has been heavily involved in neuronal motility, including migration (Zheng and Poo 2007). In GnRH neurons, it has been shown that calcium entry via N-type channels is essential for migration to occur (Toba et al. 2005). Furthermore, in a distinct setting, we have previously shown that the Ca 2+ /calcineurin/nuclear factor of activated T-cells pathway is important to prime neurons for migration at the transcriptional level (Zaninetti et al. 2008).

European Journal of Neuroscience, 1998

Basic fibroblast growth factor (bFGF/FGF2) exhibits widespread biological activities in the nervo... more Basic fibroblast growth factor (bFGF/FGF2) exhibits widespread biological activities in the nervous system. However, little is known about the cascade of intracellular events that links the activation of its tyrosine kinase receptors to these effects. Here we report that, in ciliary ganglion neurons from chick embryo, this trophic factor significantly enhanced neuronal survival. The percentage of surviving neurons was reduced when intracellular calcium was chelated by adding a membrane-permeable BAPTA ester to the culture medium, while antagonists of L- and N-type voltage-dependent calcium channels were ineffective. The ionic signals in response to bFGF stimulation have been studied using cytofluorimetric and patch-clamp techniques. In single-cell Fura-2 measurements, bFGF elicited a long lasting rise of the cytosolic calcium concentration that was dependent on [Ca2+]o. In whole-cell experiments, we observed a reversible depolarization of the membrane resting potential and an inward cationic current. Single channel experiments, performed in the cell-attached configuration, provide evidence for the activation of two families of Ca2+-permeable cationic channels. Moreover, inositol 1,4,5-trisphosphate opens channels with similar properties, suggesting that this cytosolic messenger can be responsible for the calcium influx induced by bFGF.

Current Medicinal Chemistry, 2012

Current Alzheimer Research, 2018

Background: It is well known that alterations in astrocytes occur in Alzheimer’s disease and reac... more Background: It is well known that alterations in astrocytes occur in Alzheimer’s disease and reactive astrogliosis is one of the hallmarks of the disease. Recently, data has emerged that suggests that alterations in astrocytes may also occur early in the pathogenesis of the disease. Objective: The aim of present work was to characterize the transcriptional alterations occurring in cultured astrocytes from 3xTg-AD mouse pups compared to control non-transgenic mice. Furthermore, we also compared these changes to those reported by others in astrocytes from symptomatic AD mice. Method: We conducted a whole-genome microarray study on primary cultured astrocytes from the hippocampus of 3xTg-AD and non-transgenic mouse newborn pups. We used cross-platform normalization and an unsupervised hierarchical clustering algorithm to compare our results with other datasets of cultured or freshly isolated astrocytes, including those isolated from plaque-stage APPswe/PS1dE9 AD mice. Results: We found...

Ca 2+ is among the most important intracellular second messengers participating in a plethora of ... more Ca 2+ is among the most important intracellular second messengers participating in a plethora of biological processes, and the measurement of Ca 2+ fluctuations is significant in the phenomenology of the underlying processes. Aequorin-based Ca 2+ probes represent an invaluable tool for reliable measurement of Ca 2+ concentrations and dynamics in different subcellular compartments. However, their use is limited due to the lack on the market of ready-to-use, cost-effective, and portable devices for the detection and readout of the low-intensity bioluminescence signal produced by these probes. Silicon photomultipliers (SiPMs) are rapidly evolving solidstate sensors for low light detection, with single photon sensitivity and photon number resolving capability, featuring low cost, low voltage, and compact format. Thus, they may represent the sensors of choice for the development of such devices and, more in general, of a new generation of multipurpose bioluminescence detectors suitable for cell biology studies. Ideally, a detector customized for these purposes must combine high dynamic range with high fidelity in reconstructing the light intensity signal temporal profile. In this article, the ability to perform aequorin-based intracellular Ca 2+ measurements using a multipurpose, low-cost setup exploiting SiPMs as the sensors is demonstrated. SiPMs turn out to assure performances comparable to those exhibited by a custom-designed photomultiplier tube-based aequorinometer. Moreover, the flexibility of SiPM-based devices might pave the way toward routinely and wide scale application of innovative biophysical protocols.

AIMS molecular science, 2018

The last decades have seen an explosive increase in the development of nanoparticles and in their... more 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.

Biochimica et biophysica acta. Molecular cell research, Jun 1, 2002

The electrical responses elicited by the muscarinic cholinergic pathway have been studied in cult... more The electrical responses elicited by the muscarinic cholinergic pathway have been studied in cultured embryonic chick ciliary ganglion (CG) neurons. Neurons obtained from E7-E8 ganglia were maintained in serum-free medium for 1 to 3 days. Stimulation with 50 AM muscarine induced depolarizing responses in about 30% of the cells tested. In voltage clamp experiments at a holding potential of À 50 mV, an inward current could be recorded in the same percentage of cells in response to muscarinic stimulation. In single channel experiments, with standard physiological solution in the pipette, muscarine transiently activated an inward conducting channel. Cell-attached recordings with 100 mM CaCl 2 in the pipette provided evidence that muscarinic agonists can activate a cationic calcium-permeable channel. Two main conductance levels could be detected, of 2.3 F 0.6 and 5.6 F 0.6 pS, respectively. In excised patches, addition of 5-20 AM inositol 1,4,5trisphosphate (InsP 3) to the bath reactivated a channel that could be blocked by heparin and whose characteristics were very similar to those of the channel seen in response to muscarinic stimulation. A channel with similar properties has been previously shown to be activated by basic fibroblast growth factor (bFGF) and InsP 3 in the same preparation.

Journal of Neurochemistry, Jan 19, 2011

Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and m... more Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and migrate in association with olfactory nerves (vomeronasal and terminal) to enter into the forebrain and reach their final destinations (Schwanzel-Fukuda and Pfaff 1989; Wray et al. 1989). The mechanisms underlying the establishment of the migration route and the movement of GnRH neurons are thought to involve different classes of molecules (for a review, see Tobet and Schwarting 2006). First of all, it is likely that transcriptional programs regulate the capacity and timing of GnRH neurons to migrate (Tobet and Schwarting 2006; Zaninetti et al. 2008; Orso et al. 2009). Secondly, it has been shown that a cohort of other pathways, including neurotransmitters, adhesion molecules, cell-cell interaction proteins, participate in the coordination of this migratory behaviour (Tobet and Schwarting 2006). It is likely that many of these molecules are necessary to generate gradients of attractant or to decode such gradients in the migrating GnRH-secreting neuron. Calcium is a universal signal, and its capacity to encode intracellular messages via spatial, temporal and amplitude characteristics allows it to participate in most cellular events, from egg fertilization to cell death, from neurotransmitter release to post-synaptic responses (Berridge 2001). In this view, it is not surprising that it has been heavily involved in neuronal motility, including migration (Zheng and Poo 2007). In GnRH neurons, it has been shown that calcium entry via N-type channels is essential for migration to occur (Toba et al. 2005). Furthermore, in a distinct setting, we have previously shown that the Ca 2+ /calcineurin/nuclear factor of activated T-cells pathway is important to prime neurons for migration at the transcriptional level (Zaninetti et al. 2008).

Scientific Reports, Feb 9, 2018

Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications,... more Engineered silica nanoparticles (NPs) have attracted increasing interest in several applications, and particularly in the field of nanomedicine, thanks to the high biocompatibility of this material. For their optimal and controlled use, the understanding of the mechanisms elicited by their interaction with the biological target is a prerequisite, especially when dealing with cells particularly vulnerable to environmental stimuli like neurons. Here we have combined different electrophysiological approaches (both at the single cell and at the population level) with a genomic screening in order to analyze, in GT1-7 neuroendocrine cells, the impact of SiO 2 NPs (50 ± 3 nm in diameter) on electrical activity and gene expression, providing a detailed analysis of the impact of a nanoparticle on neuronal excitability. We find that 20 µg mL −1 NPs induce depolarization of the membrane potential, with a modulation of the firing of action potentials. Recordings of electrical activity with multielectrode arrays provide further evidence that the NPs evoke a temporary increase in firing frequency, without affecting the functional behavior on a time scale of hours. Finally, NPs incubation up to 24 hours does not induce any change in gene expression. The fast development of nanoparticles (NPs) designed and engineered to be employed as tools for targeting to specific cells and tissues and for drug delivery has opened an entire new field in both basic science and medical applications. A preliminary, albeit essential, phase was devoted at addressing the concerns about their potential toxicity in vitro and, more relevantly, in vivo. A huge amount of papers 1-3 has evidenced the parameters (size, concentration, surface properties, etc.) that can determine the presence or absence of toxic effects, thus providing the rational background for designing safe and biocompatible nanotools. The next step is to switch the focus on the more subtle effects that can arise from a prolonged presence of NPs in contact with cells, and to understand the mechanisms that underlie the interaction between objects at the nanoscale and their cellular and molecular targets. This task is particularly relevant when the target is represented by single nerve cells or by complex neuronal networks. Engineered silica NPs have encountered a rapid diffusion in several applications in the last decade 4 , specifically in nanomedicine, thanks to the high biocompatibility of this material 5. We have reported that amorphous 50 nm SiO 2 NPs can be made fluorescent by hybridization with cyanine dyes and can be safely incorporated into neurons 6 and other cell types 7. In a previous paper, we have shown that 50 nm SiO 2 NPs, at non-toxic doses, elicit increases in the intracellular calcium concentration, [Ca 2+ ] i , in a neuroendocrine cell line, GT1-7 cells 8. These signals are fully dependent on calcium influx, carried through different types of calcium permeable channels, and are completely reversible even in the continuous presence of NPs. A few other papers 3,9-11 have reported that NPs of different composition can elicit changes in neuronal [Ca 2+ ] i. This is a relevant topic, since perturbations of

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2020

Bioluminescence detection requires single-photon sensitivity, extremely low detection limits and ... more Bioluminescence detection requires single-photon sensitivity, extremely low detection limits and wide dynamic range. Such performances were traditionally assured by photomultiplier-tubes based systems. However, development of novel applications and industrialisation call for the introduction of more robust, compact and scalable devices. Silicon photomultipliers were recently put forward as the alternative to phototubes for a new generation of flexible and user friendly instruments. In this article, the figures of merit of a silicon-photomultiplier based system relying on a compact, low cost system are investigated. Possible implementations are proposed and a proof-of-principle bioluminescence measurement is performed.

Scientific Reports, Mar 9, 2023

Cancers

The tumoral microenvironment often displays peculiar features, including accumulation of extracel... more The tumoral microenvironment often displays peculiar features, including accumulation of extracellular ATP, hypoxia, low pH-acidosis, as well as an imbalance in zinc (Zn2+) and calcium (Ca2+). 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 µM), 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 ...

Neurosignals, 2005

In a neuronal subpopulation, AA at the same concentration was also able to elicit calcium release... more In a neuronal subpopulation, AA at the same concentration was also able to elicit calcium release from thapsigargin-sensitive intracellular stores; we provide evidence that cytochrome P450 epoxygenase is involved in this process.

Journal of Neurochemistry, 2011

Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and m... more Developing gonadotropin-releasing hormone (GnRH) neurons originate in the nasal compartment and migrate in association with olfactory nerves (vomeronasal and terminal) to enter into the forebrain and reach their final destinations (Schwanzel-Fukuda and Pfaff 1989; Wray et al. 1989). The mechanisms underlying the establishment of the migration route and the movement of GnRH neurons are thought to involve different classes of molecules (for a review, see Tobet and Schwarting 2006). First of all, it is likely that transcriptional programs regulate the capacity and timing of GnRH neurons to migrate (Tobet and Schwarting 2006; Zaninetti et al. 2008; Orso et al. 2009). Secondly, it has been shown that a cohort of other pathways, including neurotransmitters, adhesion molecules, cell-cell interaction proteins, participate in the coordination of this migratory behaviour (Tobet and Schwarting 2006). It is likely that many of these molecules are necessary to generate gradients of attractant or to decode such gradients in the migrating GnRH-secreting neuron. Calcium is a universal signal, and its capacity to encode intracellular messages via spatial, temporal and amplitude characteristics allows it to participate in most cellular events, from egg fertilization to cell death, from neurotransmitter release to post-synaptic responses (Berridge 2001). In this view, it is not surprising that it has been heavily involved in neuronal motility, including migration (Zheng and Poo 2007). In GnRH neurons, it has been shown that calcium entry via N-type channels is essential for migration to occur (Toba et al. 2005). Furthermore, in a distinct setting, we have previously shown that the Ca 2+ /calcineurin/nuclear factor of activated T-cells pathway is important to prime neurons for migration at the transcriptional level (Zaninetti et al. 2008).

European Journal of Neuroscience, 1998

Basic fibroblast growth factor (bFGF/FGF2) exhibits widespread biological activities in the nervo... more Basic fibroblast growth factor (bFGF/FGF2) exhibits widespread biological activities in the nervous system. However, little is known about the cascade of intracellular events that links the activation of its tyrosine kinase receptors to these effects. Here we report that, in ciliary ganglion neurons from chick embryo, this trophic factor significantly enhanced neuronal survival. The percentage of surviving neurons was reduced when intracellular calcium was chelated by adding a membrane-permeable BAPTA ester to the culture medium, while antagonists of L- and N-type voltage-dependent calcium channels were ineffective. The ionic signals in response to bFGF stimulation have been studied using cytofluorimetric and patch-clamp techniques. In single-cell Fura-2 measurements, bFGF elicited a long lasting rise of the cytosolic calcium concentration that was dependent on [Ca2+]o. In whole-cell experiments, we observed a reversible depolarization of the membrane resting potential and an inward cationic current. Single channel experiments, performed in the cell-attached configuration, provide evidence for the activation of two families of Ca2+-permeable cationic channels. Moreover, inositol 1,4,5-trisphosphate opens channels with similar properties, suggesting that this cytosolic messenger can be responsible for the calcium influx induced by bFGF.

Current Medicinal Chemistry, 2012

Current Alzheimer Research, 2018

Background: It is well known that alterations in astrocytes occur in Alzheimer’s disease and reac... more Background: It is well known that alterations in astrocytes occur in Alzheimer’s disease and reactive astrogliosis is one of the hallmarks of the disease. Recently, data has emerged that suggests that alterations in astrocytes may also occur early in the pathogenesis of the disease. Objective: The aim of present work was to characterize the transcriptional alterations occurring in cultured astrocytes from 3xTg-AD mouse pups compared to control non-transgenic mice. Furthermore, we also compared these changes to those reported by others in astrocytes from symptomatic AD mice. Method: We conducted a whole-genome microarray study on primary cultured astrocytes from the hippocampus of 3xTg-AD and non-transgenic mouse newborn pups. We used cross-platform normalization and an unsupervised hierarchical clustering algorithm to compare our results with other datasets of cultured or freshly isolated astrocytes, including those isolated from plaque-stage APPswe/PS1dE9 AD mice. Results: We found...

Ca 2+ is among the most important intracellular second messengers participating in a plethora of ... more Ca 2+ is among the most important intracellular second messengers participating in a plethora of biological processes, and the measurement of Ca 2+ fluctuations is significant in the phenomenology of the underlying processes. Aequorin-based Ca 2+ probes represent an invaluable tool for reliable measurement of Ca 2+ concentrations and dynamics in different subcellular compartments. However, their use is limited due to the lack on the market of ready-to-use, cost-effective, and portable devices for the detection and readout of the low-intensity bioluminescence signal produced by these probes. Silicon photomultipliers (SiPMs) are rapidly evolving solidstate sensors for low light detection, with single photon sensitivity and photon number resolving capability, featuring low cost, low voltage, and compact format. Thus, they may represent the sensors of choice for the development of such devices and, more in general, of a new generation of multipurpose bioluminescence detectors suitable for cell biology studies. Ideally, a detector customized for these purposes must combine high dynamic range with high fidelity in reconstructing the light intensity signal temporal profile. In this article, the ability to perform aequorin-based intracellular Ca 2+ measurements using a multipurpose, low-cost setup exploiting SiPMs as the sensors is demonstrated. SiPMs turn out to assure performances comparable to those exhibited by a custom-designed photomultiplier tube-based aequorinometer. Moreover, the flexibility of SiPM-based devices might pave the way toward routinely and wide scale application of innovative biophysical protocols.