Giorgia Conte
@isof.cnr.it
Institute for Organic Synthesis and Photoreactivity
italian national council of research
RESEARCH, TEACHING, or OTHER INTERESTS
Neuroscience, Materials Science, Molecular Biology, Cell Biology
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Mariana Alves, Laura de Diego-Garcia, Gloria Vegliante, Oscar Moreno, Beatriz Gil, Pedro Ramos-Cabrer, Meghma Mitra, Ana Fernandez Martin, Aida Menéndez-Méndez, Yitao Wang,et al.
Ivyspring International Publisher
Purpose: Post-traumatic epilepsy (PTE) is one of the most common life-quality reducing consequences of traumatic brain injury (TBI). However, to date there are no pharmacological approaches to predict or to prevent the development of PTE. The P2X7 receptor (P2X7R) is a cationic ATP-dependent membrane channel that is expressed throughout the brain. While increasing evidence suggests a role for the P2X7R during seizures and epilepsy, it is unclear if changes in P2X7R expression can predict TBI-induced epilepsy development, and whether P2X7R antagonism can protect against long-lasting brain hyperexcitability caused by TBI. Methods: TBI was induced in adult male mice using the controlled cortical impact model (CCI). To test the anti-epileptogenic effects of P2X7R antagonism, mice were treated with brain-penetrant P2X7R antagonists JNJ-54175446 (30 mg/kg) or AFC-5128 (30 mg/kg) for 7 days post-CCI. The cell-type specific effects of P2X7Rs on TBI-induced hyperexcitability were analyzed in mice lacking exon 2 of the P2rx7 gene selectively in microglia (P2rx7:Cx3cr1-Cre). Static positron emission tomography (PET) via an intravenous injection of the P2X7R radioligand 18F-JNJ-64413739 and magnetic resonance imaging (MRI) were conducted twice during the first- and third-week post-injury. Results: Following TBI, while there were no obvious changes in P2X7R protein levels in the ipsilateral hippocampus post-injury, there was a delayed increase in P2X7R protein levels in the ipsilateral cortex at 3 months post-injury. Treatment with P2X7R antagonists shortly after TBI reduced long-lasting brain hyperexcitability, reduced cortical contusion volume, and normalized injury-induced hyperactivity to control sham-levels at 3 weeks post-TBI. Notably, mice lacking P2rx7 in microglia had an increased seizure threshold after TBI, suggesting that P2X7R contributed to brain hyperexcitability via its effects on microglia. Finally, P2X7R radioligand uptake after TBI correlated with seizure threshold at 3 weeks post-injury. Conclusions: Our results demonstrate the antiepileptogenic potential of P2X7R antagonism to prevent TBI-induced epilepsy and indicate that P2X7R-based PET imaging may be a useful diagnostic tool to identify people at risk of developing PTE.
Roberta Fabbri, Alessandra Scidà, Emanuela Saracino, Giorgia Conte, Alessandro Kovtun, Andrea Candini, Denisa Kirdajova, Diletta Spennato, Valeria Marchetti, Chiara Lazzarini,et al.
Springer Science and Business Media LLC
Roberta Fabbri, Alessandra Scidà, Emanuela Saracino, Giorgia Conte, Alessandro Kovtun, Andrea Candini, Denisa Kirdajova, Diletta Spennato, Valeria Marchetti, Chiara Lazzarini,et al.
Springer Science and Business Media LLC
AbstractAstrocytes are responsible for maintaining homoeostasis and cognitive functions through calcium signalling, a process that is altered in brain diseases. Current bioelectronic tools are designed to study neurons and are not suitable for controlling calcium signals in astrocytes. Here, we show that electrical stimulation of astrocytes using electrodes coated with graphene oxide and reduced graphene oxide induces respectively a slow response to calcium, mediated by external calcium influx, and a sharp one, exclusively due to calcium release from intracellular stores. Our results suggest that the different conductivities of the substrate influence the electric field at the cell–electrolyte or cell–material interfaces, favouring different signalling events in vitro and ex vivo. Patch-clamp, voltage-sensitive dye and calcium imaging data support the proposed model. In summary, we provide evidence of a simple tool to selectively control distinct calcium signals in brain astrocytes for straightforward investigations in neuroscience and bioelectronic medicine.
Mariana Alves, Beatriz Gil, Javier Villegas-Salmerón, Valentina Salari, Ricardo Martins-Ferreira, Marina Arribas Blázquez, Aida Menéndez Méndez, Rogerio Da Rosa Gerbatin, Jonathon Smith, Laura de Diego-Garcia,et al.
Elsevier BV
Jonathon Smith, Aida Menéndez Méndez, Mariana Alves, Alberto Parras, Giorgia Conte, Anindya Bhattacharya, Marc Ceusters, Annette Nicke, David C. Henshall, Eva M. Jimenez‐Mateos,et al.
Wiley
Background and PurposeNeonatal seizures represent a clinical emergency. However, current anti‐seizure medications fail to resolve seizures in ~50% of infants. The P2X7 receptor (P2X7R) is an important driver of inflammation, and evidence suggests that P2X7R contributes to seizures and epilepsy in adults. However, no genetic proof has yet been provided to determine what contribution P2X7R makes to neonatal seizures, its effects on inflammatory signalling during neonatal seizures, and the therapeutic potential of P2X7R‐based treatments on long‐lasting brain excitability.Experimental ApproachNeonatal seizures were induced by global hypoxia in 7‐day‐old mouse pups (P7). The role of P2X7Rs during seizures was analysed in P2X7R‐overexpressing and knockout mice. Treatment of wild‐type mice after hypoxia with the P2X7R antagonist JNJ‐47965567 was used to determine the effects of the P2X7R on long‐lasting brain hyperexcitability. Cell type‐specific P2X7R expression was analysed in P2X7R‐EGFP reporter mice. RNA sequencing was used to monitor P2X7R‐dependent hippocampal downstream signalling.Key ResultsP2X7R deletion reduced seizure severity, whereas P2X7R overexpression exacerbated seizure severity and reduced responsiveness to anti‐seizure medication. P2X7R deficiency led to an anti‐inflammatory phenotype in microglia, and treatment of mice with a P2X7R antagonist reduced long‐lasting brain hyperexcitability. RNA sequencing identified several pathways altered in P2X7R knockout mice after neonatal hypoxia, including a down‐regulation of genes implicated in inflammation and glutamatergic signalling.Conclusion and ImplicationsTreatments based on targeting the P2X7R may represent a novel therapeutic strategy for neonatal seizures with P2X7Rs contributing to the generation of neonatal seizures, driving inflammatory processes and long‐term hyperexcitability states.
R. Fabbri, Diletta Spennato, Giorgia Conte, Aikaterini Konstantoulaki, C. Lazzarini, E. Saracino, G. P. Nicchia, A. Frigeri, Roberto Zamboni, D. Spray and V. Benfenati
Edward Beamer, James Morgan, Mariana Alves, Aida Menéndez Méndez, Gareth Morris, Béla Zimmer, Giorgia Conte, Laura de Diego‐Garcia, Cristina Alarcón‐Vila, Nico Ka Yiu Ng,et al.
Wiley
Background and PurposeRefractory status epilepticus is a clinical emergency associated with high mortality and morbidity. Increasing evidence suggests neuroinflammation contributes to the development of drug‐refractoriness during status epilepticus. Here, we have determined the contribution of the ATP‐gated P2X7 receptor, previously linked to inflammation and increased hyperexcitability, to drug‐refractory status epilepticus and its therapeutic potential.Experimental ApproachStatus epilepticus was induced via a unilateral microinjection of kainic acid into the amygdala in adult mice. Severity of status epilepticus was compared in animals with overexpressing or knock‐out of the P2X7 receptor, after inflammatory priming by pre‐injection of bacterial lipopolysaccharide (LPS) and in mice treated with P2X7 receptor‐targeting and anti‐inflammatory drugs.Key ResultsMice overexpressing P2X7 receptors were unresponsive to several anticonvulsants (lorazepam, midazolam, phenytoin and carbamazepine) during status epilepticus. P2X7 receptor expression increased in microglia during status epilepticus, at times when responses to anticonvulsants were reduced. Overexpression of P2X7 receptors induced a pro‐inflammatory phenotype in microglia during status epilepticus and the anti‐inflammatory drug minocycline restored normal responses to anticonvulsants in mice overexpressing P2X7 receptors. Pretreatment of wild‐type mice with LPS increased P2X7 receptor levels in the brain and reduced responsiveness to anticonvulsants during status epilepticus, which was overcome by either genetic deletion of P2X7 receptors or treatment with the P2X7 receptor antagonists, AFC‐5128 or ITH15004.Conclusion and ImplicationsOur results demonstrate that P2X7 receptor‐induced pro‐inflammatory effects contribute to resistance to pharmacotherapy during status epilepticus. Therapies targeting P2X7 receptors could be novel adjunctive treatments for drug‐refractory status epilepticus.
Giorgia Conte, Aida Menéndez-Méndez, Sebastian Bauer, Hany El-Naggar, Mariana Alves, Annette Nicke, Norman Delanty, Felix Rosenow, David C. Henshall, and Tobias Engel
MDPI AG
Circulating molecules have potential as biomarkers to support the diagnosis of epilepsy and to assist with differential diagnosis, for example, in conditions resembling epilepsy, such as in psychogenic non-epileptic seizures (PNES). The P2X7 receptor (P2X7R) is an important regulator of inflammation and mounting evidence supports its activation in the brain during epilepsy. Whether the P2X7R or P2X7R-dependent signaling molecules can be used as biomarkers of epilepsy has not been reported. P2X7R levels were analyzed by quantitative ELISA using plasma samples from controls and patients with temporal lobe epilepsy (TLE) or PNES. Moreover, blood cell P2X7R expression and P2X7R-dependent cytokine signature was measured following status epilepticus in P2X7R-EGFP reporter, wildtype, and P2X7R-knockout mice. P2X7R plasma levels were higher in TLE patients when compared with controls and patients with PNES. Plasma levels of the broad inflammatory marker protein C-Reactive protein (CRP) were similar between the three groups. Using P2X7R-EGFP reporter mice, we identified monocytes as the main blood cell type expressing P2X7R after experimentally evoked seizures. Finally, cytokine array analysis in P2X7R-deficient mice identified KC/GRO as a potential P2X7R-dependent plasma biomarker following status epilepticus and during epilepsy. Our data suggest that P2X7R signaling components may be a promising subclass of circulating biomarkers to support the diagnosis of epilepsy.
Edward Beamer, Austin Lacey, Mariana Alves, Giorgia Conte, Faming Tian, Laura de Diego‐Garcia, Mohamed Khalil, Felix Rosenow, Norman Delanty, Nicholas Dale,et al.
Wiley
AbstractObjectiveThere is a major unmet need for a molecular biomarker of seizures or epilepsy that lends itself to fast, affordable detection in an easy‐to‐use point‐of‐care device. Purines such as adenosine triphosphate and adenosine are potent neuromodulators released during excessive neuronal activity that are also present in biofluids. Their biomarker potential for seizures and epilepsy in peripheral blood has, however, not yet been investigated. The aim of the present study was to determine whether blood purine nucleoside measurements can serve as a biomarker for the recent occurrence of seizures and to support the diagnosis of epilepsy.MethodsBlood purine concentrations were measured via a point‐of‐care diagnostic technology based on the summated electrochemical detection of adenosine and adenosine breakdown products (inosine, hypoxanthine, and xanthine; SMARTChip). Measurements of blood purine concentrations were carried out using samples from mice subjected to intra‐amygdala kainic acid‐induced status epilepticus and in video‐electroencephalogram (EEG)‐monitored adult patients with epilepsy.ResultsIn mice, blood purine concentrations were rapidly increased approximately two‐ to threefold after status epilepticus (2.32 ± .40 µmol·L–1 [control] vs. 8.93 ± 1.03 µmol·L–1 [after status epilepticus]), and levels correlated with seizure burden and postseizure neurodegeneration in the hippocampus. Blood purine concentrations were also elevated in patients with video‐EEG‐diagnosed epilepsy (2.39 ± .34 µmol·L–1 [control, n = 13] vs. 4.35 ± .38 µmol·L–1 [epilepsy, n = 26]).SignificanceOur data provide proof of concept that the measurement of blood purine concentrations may offer a rapid, low‐volume bedside test to support the diagnosis of seizures and epilepsy.
Antonio Ramírez-Fernández, Lidia Urbina-Treviño, Giorgia Conte, Mariana Alves, Björn Rissiek, Anna Durner, Nicolas Scalbert, Jiong Zhang, Tim Magnus, Friedrich Koch-Nolte,et al.
Springer Science and Business Media LLC
AbstractThe ATP-gated P2X7 receptor is highly expressed in microglia and has been involved in diverse brain diseases. P2X7 effects were also described in neurons and astrocytes but its localisation and function in these cell types has been challenging to demonstrate in situ. BAC transgenic mouse lines have greatly advanced neuroscience research and two BAC-transgenic P2X7 reporter mouse models exist in which either a soluble EGFP (sEGFP) or an EGFP-tagged P2X7 receptor (P2X7-EGFP) is expressed under the control of a BAC-derived P2rx7 promoter. Here we evaluate both mouse models and find striking differences in both P2X expression levels and EGFP reporter expression patterns. Most remarkably, the sEGFP model overexpresses a P2X4 passenger gene and sEGFP shows clear neuronal localisation but appears to be absent in microglia. Preliminary functional analysis in a status epilepticus model suggests functional consequences of the observed P2X receptor overexpression. In summary, an aberrant EGFP reporter pattern and possible effects of P2X4 and/or P2X7 protein overexpression need to be considered when working with this model. We further discuss reasons for the observed differences and possible caveats in BAC transgenic approaches.
Giorgia Conte, Alberto Parras, Mariana Alves, Ivana Ollà, Laura De Diego‐Garcia, Edward Beamer, Razi Alalqam, Alejandro Ocampo, Raúl Mendez, David C. Henshall,et al.
Wiley
AbstractObjectivePharmacoresistance and the lack of disease‐modifying actions of current antiseizure drugs persist as major challenges in the treatment of epilepsy. Experimental models of chemoconvulsant‐induced status epilepticus remain the models of choice to discover potential antiepileptogenic drugs, but doubts remain as to the extent to which they model human pathophysiology. The aim of the present study was to compare the molecular landscape of the intra‐amygdala kainic acid model of status epilepticus in mice with findings in resected brain tissue from patients with drug‐resistant temporal lobe epilepsy (TLE).MethodsStatus epilepticus was induced via intra‐amygdala microinjection of kainic acid in C57BL/6 mice, and gene expression was analyzed via microarrays in hippocampal tissue at acute and chronic time‐points. Results were compared to reference datasets in the intraperitoneal pilocarpine and intrahippocampal kainic acid model and to human resected brain tissue (hippocampus and cortex) from patients with drug‐resistant TLE.ResultsIntra‐amygdala kainic acid injection in mice triggered extensive dysregulation of gene expression that was ~3‐fold greater shortly after status epilepticus (2729 genes) when compared to epilepsy (412). Comparison to samples from patients with TLE revealed a particularly high correlation of gene dysregulation during established epilepsy. Pathway analysis found suppression of calcium signaling to be highly conserved across different models of epilepsy and patients. cAMP response element‐binding protein (CREB) was predicted as one of the main upstream transcription factors regulating gene expression during acute and chronic phases, and inhibition of CREB reduced seizure severity in the intra‐amygdala kainic acid model.SignificanceOur findings suggest the intra‐amygdala kainic acid model faithfully replicates key molecular features of human drug‐resistant TLE and provides potential rational target approaches for disease‐modification through new insights into the unique and shared gene expression landscape in experimental epilepsy.
James Morgan, Mariana Alves, Giorgia Conte, Aida Menéndez-Méndez, Laura de Diego-Garcia, Gioacchino de Leo, Edward Beamer, Jonathon Smith, Annette Nicke, and Tobias Engel
Springer Science and Business Media LLC
Giorgia Conte, Ngoc T. Nguyen, Mariana Alves, Laura de Diego-Garcia, Aidan Kenny, Annette Nicke, David C. Henshall, Eva M. Jimenez-Mateos, and Tobias Engel
Frontiers Media SA
The ionotropic ATP-gated P2X7 receptor is an important contributor to inflammatory signaling cascades via the release of Interleukin-1β, as well as having roles in cell death, neuronal plasticity and the release of neurotransmitters. Accordingly, there is interest in targeting the P2X7 receptor for the treatment of epilepsy. However, the signaling pathways downstream of P2X7 receptor activation remain incompletely understood. Notably, recent studies showed that P2X7 receptor expression is controlled, in part, by microRNAs (miRNAs). Here, we explored P2X7 receptor-dependent microRNA expression by comparing microRNA expression profiles of wild-type (wt) and P2X7 receptor knockout mice before and after status epilepticus. Genome-wide microRNA profiling was performed using hippocampi from wt and P2X7 receptor knockout mice following status epilepticus induced by intra-amygdala kainic acid. This revealed that the genetic deletion of the P2X7 receptor results in distinct patterns of microRNA expression. Specifically, we found that in vehicle-injected control mice, the lack of the P2X7 receptor resulted in the up-regulation of 50 microRNAs and down-regulation of 35 microRNAs. Post-status epilepticus, P2X7 receptor deficiency led to the up-regulation of 44 microRNAs while 13 microRNAs were down-regulated. Moreover, there was only limited overlap among identified P2X7 receptor-dependent microRNAs between control conditions and post-status epilepticus, suggesting that the P2X7 receptor regulates the expression of different microRNAs during normal physiology and pathology. Bioinformatic analysis revealed that genes targeted by P2X7 receptor-dependent microRNAs were particularly overrepresented in pathways involved in intracellular signaling, inflammation, and cell death; processes that have been repeatedly associated with P2X7 receptor activation. Moreover, whereas genes involved in signaling pathways and inflammation were common among up- and down-regulated P2X7 receptor-dependent microRNAs during physiological and pathological conditions, genes associated with cell death seemed to be restricted to up-regulated microRNAs during both physiological conditions and post-status epilepticus. Taken together, our results demonstrate that the P2X7 receptor impacts on the expression profile of microRNAs in the brain, thereby possibly contributing to both the maintenance of normal cellular homeostasis and pathological processes.
Alberto Parras, Laura de Diego-Garcia, Mariana Alves, Edward Beamer, Giorgia Conte, Eva M Jimenez-Mateos, James Morgan, Ivana Ollà, Yasmina Hernandez-Santana, Norman Delanty,et al.
Oxford University Press (OUP)
Abstract Temporal lobe epilepsy is the most common and refractory form of epilepsy in adults. Gene expression within affected structures such as the hippocampus displays extensive dysregulation and is implicated as a central pathomechanism. Post-transcriptional mechanisms are increasingly recognized as determinants of the gene expression landscape, but key mechanisms remain unexplored. Here we show, for first time, that cytoplasmic mRNA polyadenylation, one of the post-transcriptional mechanisms regulating gene expression, undergoes widespread reorganization in temporal lobe epilepsy. In the hippocampus of mice subjected to status epilepticus and epilepsy, we report >25% of the transcriptome displays changes in their poly(A) tail length, with deadenylation disproportionately affecting genes previously associated with epilepsy. Suggesting cytoplasmic polyadenylation element binding proteins (CPEBs) being one of the main contributors to mRNA polyadenylation changes, transcripts targeted by CPEBs were particularly enriched among the gene pool undergoing poly(A) tail alterations during epilepsy. Transcripts bound by CPEB4 were over-represented among transcripts with poly(A) tail alterations and epilepsy-related genes and CPEB4 expression was found to be increased in mouse models of seizures and resected hippocampi from patients with drug-refractory temporal lobe epilepsy. Finally, supporting an adaptive function for CPEB4, deletion of Cpeb4 exacerbated seizure severity and neurodegeneration during status epilepticus and the development of epilepsy in mice. Together, these findings reveal an additional layer of gene expression regulation during epilepsy and point to novel targets for seizure control and disease-modification in epilepsy.
Annalisa Bernareggi, Giorgia Conte, Andrew Constanti, Violetta Borelli, Francesca Vita, and Giuliano Zabucchi
Springer Science and Business Media LLC
AbstractThe so-called amphibole asbestos fibers are enriched with mineral iron ions, able to stimulate ROS production. We recently reported that crocidolite asbestos was able to interact with the cell membranes of Xenopus laevis oocytes, to alter their electrical membrane properties. Here, we found that applied iron ions (Fe3+) or H2O2 (for ROS generation) mimicked these effects, suggesting that at least one effect of iron-containing asbestos fiber exposure was mediated by ROS production. Furthermore, combined Fe3+ and H2O2 acted synergistically, producing a membrane effect stronger than that induced by these factors alone. Similar to crocidolite, these changes peaked within 30 minutes of incubation and vanished almost completely after 120 min. However, in the presence of cytochalasin D, which inhibits membrane actin repair mechanisms, crocidolite or applied Fe3+/H2O2 invariably produced oocyte cell death. While the electrophysiological modifications induced by crocidolite suggested a modification of an intrinsic chloride ion channel, the morphological appearance of the treated oocytes also indicated the formation of membrane “pores”; the effects of asbestos exposure may therefore consist of multiple (not necessarily exclusive) underlying mechanisms. In conclusion, using Xenopus oocytes allowed us for the first time, to focus on a specific membrane effect of crocidolite asbestos exposure, which deserves to be tested also on human lung cell lines. Much available evidence suggests that asbestos fibers damage cells through the production of ROS. Our present data confirm that crocidolite fibers can indeed trigger ROS-mediated damaging effects in the oocyte cell membrane, provided iron ions and H2O2 are available for ROS production.
Edward Beamer, Giorgia Conte, and Tobias Engel
Elsevier BV
Mariana Alves, Laura De Diego Garcia, Giorgia Conte, Eva M. Jimenez-Mateos, Beatrice D'Orsi, Amaya Sanz-Rodriguez, Jochen H.M. Prehn, David C. Henshall, and Tobias Engel
Society for Neuroscience
Extracellular ATP activates inflammatory responses to tissue injury. It is also implicated in establishing lasting network hyperexcitability in the brain by acting upon independent receptor systems. Whereas the fast-acting P2X channels have well-established roles driving neuroinflammation and increasing hyperexcitability, the slower-acting metabotropic P2Y receptors have received much less attention. Recent studies of P2Y1 receptor function in seizures and epilepsy have produced contradictory results, suggesting that the role of this receptor during seizure pathology may be highly sensitive to context. Here, by using male mice, we demonstrate that the metabotropic P2Y1 receptor mediates either proconvulsive or anticonvulsive responses, dependent on the time point of activation in relation to the induction of status epilepticus. P2Y1 deficiency or a P2Y1 antagonist (MRS2500) administered before a chemoconvulsant, exacerbates epileptiform activity, whereas a P2Y1 agonist (MRS2365) administered at this time point is anticonvulsant. When these drugs are administered after the onset of status epilepticus, however, their effect on seizure severity is reversed, with the antagonist now anticonvulsant and the agonist proconvulsant. This result was consistent across two different mouse models of status epilepticus (intra-amygdala kainic acid and intraperitoneal pilocarpine). Pharmacologic P2Y1 blockade during status epilepticus reduces also associated brain damage, delays the development of epilepsy and, when applied during epilepsy, suppresses spontaneous seizures, in mice. Our data show a context-specific role for P2Y1 during seizure pathology and demonstrate that blocking P2Y1 after status epilepticus and during epilepsy has potent anticonvulsive effects, suggesting that P2Y1 may be a novel candidate for the treatment of drug-refractory status epilepticus and epilepsy. SIGNIFICANCE STATEMENT This is the first study to fully characterize the contribution of a metabotropic purinergic P2Y receptor during acute seizures and epilepsy. The findings suggest that targeting P2Y1 may offer a potential novel treatment strategy for drug-refractory status epilepticus and epilepsy. Our data demonstrate a context-specific role of P2Y1 activation during seizures, switching from a proconvulsive to an anticonvulsive role depending on physiopathological context. Thus, our study provides a possible explanation for seemingly conflicting results obtained between studies of different brain diseases where P2Y1 targeting has been proposed as a potential treatment strategy and highlights that the timing of pharmacological interventions is of critical importance to the understanding of how receptors contribute to the generation of seizures and the development of epilepsy.