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Pollegioni, L.

Publications and source records attributed to Pollegioni, L..

4 recordsLinked to original sources

Principles of NMDA receptor co-agonism at cortical fast-spiking GABAergic interneurons in the adolescent prefrontal cortex

N-methyl-D-aspartate receptors (NMDARs) populate fast-spiking (FS)-parvalbumin-positive (PV+) GABAergic interneurons (INs), where they play a critical role in shaping circuit motifs and memory. However, it is largely unknown whether and how NMDARs at FS-PV+-INs are gated by their co-agonists and the functional relevance of such modulations for their synaptic coupling with excitatory neurons. Here, we report that FS-PV+-INs in the adolescent mouse prefrontal cortex, an area central to complex cognitive operation exhibit functional GluN2B/D containing NMDARs. These receptors contribute to the excitatory drive of FS-PV+-INs and to the feedforward inhibition, controlling short-term and long-term synaptic plasticity. While the identity of the co-agonist controlling GABAergic tone is tuned by the synaptic activity regime from D-serine to glycine, we reveal that it remains largely unchanged at the excitatory synapse with D-serine being the sole co-agonist gating NMDARs. Lastly, we show that D-serine-deficient mice, a model of NMDAR hypofunction show selective attenuation of PV+-INs excitation together with selective loss of temporal summation and long-term plasticity at the excitatory synapse. Our study reveals the segregation of pools of NMDARs at the soma and dendrites that are differently sensitive to D-serine or glycine, the existence of distinct modes of activity-dependent regulation of these NMDARs by their co-agonists at this major type of GABAergic INs, and hence the rules governing cortical inhibition by FS-PV+-INs during a critical period of late postnatal development.

neuroscience↗

Bioinf-Farma: supervised integration of epitope prediction and recombinant protein developability for automated vaccine candidate prioritization

Vaccine antigen discovery requires prioritizing protein candidates according to both immunogenic potential and recombinant expression feasibility. These properties are typically evaluated using separate computational tools, requiring researchers to integrate heterogeneous outputs through ad hoc workflows. Here, we present BIOINF-farma, a modular platform integrating epitope prediction and developability assessment for rational antigen selection within a unified environment. Candidates can be submitted as amino acid sequences or three-dimensional structures. When experimental structures are unavailable, BIOINF-farma automatically searches for models in AlphaFold DB or performs structure prediction using Boltz-2, ensuring a standardized structural representation for downstream analyses. Antigenicity is quantified by combining structure-based conformational epitope signals (MLCE/REBELOT-BEPPE) and sequence-based linear epitope propensity scores (BepiPred 3.0) into a protein-level Antigenicity Score, with a classification threshold optimized on a manually curated validation dataset. Developability is evaluated through two supervised Random Forest meta-learners that integrate three solubility predictors (DeepSoluE, SoluProt, Protein-Sol) and three thermal stability predictors (TemStaPro, ProLaTherm, BertThermo), whose outputs are combined into an Expression Efficiency Score (EES). By integrating complementary predictive signals, the meta-learning framework achieves greater accuracy and robustness than individual predictors while maintaining performance across a broad range of sequence identities. The Antigenicity Score effectively discriminates antigenic from non-antigenic proteins with a large effect size, whereas EES successfully distinguishes soluble from insoluble outcomes on an independent panel of recombinant proteins expressed in Escherichia coli. BIOINF-farma jointly assesses antigenicity and expression feasibility within a single framework. Its modular architecture facilitates the incorporation of future predictive methods, while its web-based interface makes the full pipeline accessible to users without programming expertise, supporting rapid candidate triage in vaccine research and emerging pathogen responses. Author SummaryVaccine development begins with a critical step: identifying, among the many proteins encoded in a pathogen genome, those most suitable as candidate antigens. A promising candidate must satisfy two requirements that are rarely evaluated together. It must be recognized by the immune system, so that vaccination elicits a protective response; and it must be amenable to recombinant production, since antigens that cannot be obtained in sufficient quantity and quality are of limited practical use. Current computational tools typically address only one of these aspects, and researchers must integrate their outputs manually, through procedures that are time-consuming and prone to inconsistency. We developed BIOINF-farma, an automated platform that brings these two assessments into a single analytical framework. Starting from a protein sequence or an experimental structure, the platform retrieves or predicts a three-dimensional model, evaluates the proteins antigenic potential by combining complementary epitope predictors, and estimates its expression feasibility by integrating multiple solubility and stability predictors through supervised machine learning. A web-based interface makes the full workflow available to experimental immunologists and vaccine developers without requiring computational expertise, supporting rational candidate prioritization in routine vaccine research and during emerging pathogen responses.

bioinformatics↗

Embryonic depletion of D-aspartate perturbs NMDA receptor-dependent long-term potentiation in the hippocampus of juvenile mice

D-Aspartate (D-Asp) is an endogenous D-amino acid that exhibits a pronounced developmental peak in the mammalian brain, suggesting a potential regulatory role in glutamatergic signaling and neurodevelopment. Disruption of D-Asp homeostasis has been associated with neuropsychiatric disorders characterized by early-life circuit vulnerability, including schizophrenia and autism spectrum disorders. However, its functional impact to hippocampal physiology remains incompletely defined. Here, we investigated how constitutive D-Asp depletion affects synaptic function in the hippocampal CA1 region of Ddo-knock-in (Ddo-KI) mice, in which zygotic overexpression of the D-Asp-degrading enzyme, D-aspartate oxidase (DASPO), results in embryonic and persistent D-Asp deficiency. Electrophysiological recordings were performed in acute hippocampal slices from male and female mice at postnatal day 30 (P30) and day 60 (P60). Basal synaptic transmission, assessed through paired-pulse ratio and spontaneous excitatory/inhibitory events, was unaltered between genotypes, indicating preserved presynaptic release probability and overall excitation/inhibition balance. In contrast, NMDA receptor (NMDAR)-dependent synaptic plasticity was selectively altered, as theta-burst stimulation induced significantly greater long-term potentiation (LTP) in juvenile P30 Ddo-KI mice, whereas this difference was no longer observed at P60. Consistently, patch-clamp recordings revealed a reduced AMPAR/NMDAR ratio in P30 Ddo-KI males, suggesting an increased relative contribution of NMDAR-mediated currents. Importantly, acute bath application of exogenous D-Asp restored LTP to wild-type levels, demonstrating rapid reversibility and supporting a model of homeostatic receptor rebalancing rather than irreversible circuit alterations. Biochemical assays confirmed significantly increased DASPO activity and reduced D-Asp levels in Ddo-KI mice. However, these parameters remained stable between P30 and P60, indicating that the age-dependent plasticity phenotype is unlikely to arise from progressive biochemical changes. Together, these findings indicate that developmental D-Asp deficiency induces a transient, juvenile-specific alteration characterized by enhanced NMDAR-dependent synaptic plasticity, which can be rapidly normalized upon D-Asp re-exposure.

neuroscience↗

Co-agonist glycine controls the occurrence of bursts by activating extrasynaptic NMDARs in nigral dopamine neurons

NMDA receptor activation in pars compacta substantia nigra dopamine neurons is central to the generation of bursting activity, a key signal temporally associated to movement initiation. The site of the NMDAR pool (synaptic and/or extrasynaptic) as well as the identity of the co-agonist involved in the ignition of this phasic activity remains unknown. Using ex vivo electrophysiological recordings, we demonstrate that NMDARs located outside synapses are preponderant for this firing. This pool of receptors is recruited during intense synaptic activity via spillover of glutamate and require the binding of NMDAR co-agonist glycine for their full activation. Synaptic NMDARs are not directly involved in bursting and are activated by D-serine, a distinct co-agonist. Location dependency of NMDARs and co-agonist underlying burst generation may serve as a guideline in understanding the physiological role of dopamine neurons in health and disease. TeaserExtrasynaptic NMDARs recruited by spillover and glycine allow the generation of bursts in dopamine neurons.

neuroscience↗