Biology subjects

Lanore, F.

Publications and source records attributed to Lanore, F..

5 recordsLinked to original sources

bioRxiv2026

Human dental pulp stem cells grafted into C57BL/6J hippocampus differentiate towards immature neuronal like cells displaying action potential firing activity

Stem cell therapy represents a promising strategy for the replacement and functional restoration of damaged neural tissue in neurodegenerative conditions. Human dental pulp stem cells (hDPSCs) have emerged as potential candidates for neuroregeneration due to their ease of isolation, neural crest origin, neurotrophic and anti-inflammatory capacity, and demonstrated ability to differentiate in vitro into neuronal-like cells exhibiting electrophysiological activity. Although the immunomodulatory and neuroprotective properties of hDPSCs have been reported in multiple models of brain disease, their capacity to functionally integrate into host neuronal circuits remain poorly understood. In this study, we have grafted green fluorescent protein (GFP)-transduced, neural preconditioned hDPSCs into the CA1 region of the hippocampus of C57BL/6J mice. One month after transplantation, GFP+-hDPSCs survived in the brains of non-immunosuppressed mice and remained localized within the grafted area. Notably, the transplanted cells underwent in situ differentiation and exhibited a neuroblast-like phenotype, characterized by positive doublecortin expression and immature neuronal-like electrophysiological properties, like high membrane input resistance, low capacitance, and the ability to generate single action potentials after stimulation. Together, these findings provide the first evidence that hDPSCs can survive and integrate into the hippocampal network of the mouse brain at one-month post graft, supporting their potential use for future therapeutic applications in acute brain lesions and neurodegenerative disorders.

neuroscience↗

bioRxiv2024

Dye-based Fluorescent Organic Nanoparticles, New Promising Tools for Optogenetics

Dye-based fluorescent organic nanoparticles are a specific class of nanoparticles obtained by nanoprecipitation in water of pure dyes only. While the photophysical and colloidal properties of the nanoparticles strongly depend on the nature of the aggregated dyes, their excellent brightness in the visible and in the near infrared make these nanoparticles a unique and versatile platform for in vivo application. This article examines the promising utilization of these nanoparticles for in vivo optogenetics applications. Their photophysical properties as well as their biocompatibility and their capacity to activate Chrimson opsin in vivo through fluorescence reabsorption process are demonstrated. Additionally, an illustrative example of employing these nanoparticles in fear reduction in mice through close-loop stimulation is presented. Through an optogenetic methodology, the nanoparticles demonstrate an ability to selectively manipulate neurons implicated in the fear response and diminish the latter. Dye-based fluorescent organic nanoparticles represent a promising and innovative strategy for optogenetic applications, holding substantial potential in the domain of translational neuroscience. This work paves the way for novel therapeutic modalities for neurological and neuropsychiatric disorders.

neuroscience↗

bioRxiv2023

CA3 hippocampal synaptic plasticity supports ripple physiology during memory consolidation

Consolidation of recent memory depends on hippocampal activities during resting periods that immediately follows the memory encoding. There, Slow Save Sleep phases appear as privileged periods for memory consolidation as hosting the ripple activities, which are fast oscillations generated within the hippocampus whose inactivation leads to memory impairment. If a strong correlation exists between these replays of recent experience and the persistence of behavioural adaptations, the mobilisation, the localization and the importance of synaptic plasticity events in this process is largely unknown. To question this issue, we used cell-surface AMPAR immobilisation to block post-synaptic LTP within the hippocampal region at various steps of the memory process. 1- Our results show that hippocampal synaptic plasticity is engaged during the consolidation but is dispensable during the encoding or recall of a working memory based spatial memory task. 2- Blockade of plasticity during sleep leads to apparent forgetting of the encoded rule. 3- In vivo recordings of ripple activities during resting periods show a strong impact of AMPAR immobilization solely, prominent when a rule has been recently encoded. 4- In situ examination of the interplay between AMPAR mobility, hippocampal plasticity and spontaneous ripple activities pointed that post-synaptic plasticity at CA3-CA3 recurrent synapses support ripple generation. As crucial results were reproduced using another AMPARM blockade strategy, we propose that after rule encoding, post-synaptic AMPAR mobility at CA3 recurrent synapses support the generation of ripples necessary for rule consolidation.

neuroscience↗

bioRxiv2021

High-resolution imaging and manipulation of endogenous AMPA receptor surface mobility during synaptic plasticity and learning

Regulation of synaptic neurotransmitter receptor content is a fundamental mechanism for tuning synaptic efficacy during experience-dependent plasticity and behavioral adaptation. However, experimental approaches to track and modify receptor movements in integrated experimental systems are limited. Exploiting AMPA-type glutamate receptors (AMPAR) as a model, we generated a knock-in mouse expressing the biotin acceptor peptide (AP) tag on the GluA2 extracellular N-terminus. Cell-specific introduction of biotin ligase allows the use of monovalent or tetravalent avidin variants to respectively monitor or manipulate the surface mobility of endogenous AMPAR containing biotinylated AP-GluA2 in neuronal subsets. AMPAR immobilization precluded the expression of long-term potentiation and formation of contextual fear memory, allowing for target-specific control of the expression of synaptic plasticity and animal behavior. The AP tag knock-in model offers unprecedented access to resolve and control the spatiotemporal dynamics of endogenous receptors, and opens new avenues to study the molecular mechanisms of synaptic plasticity and learning.

neuroscience↗

bioRxiv2019

Norepinephrine controls the gain of the inhibitory circuit in the cerebellar input layer

Golgi cells (GoCs) are the main inhibitory interneurons in the input layer of the cerebellar cortex and are electrically coupled together, forming syncytia. GoCs control the excitability of granule cells (GCs) through feedforward, feedback and spillover-mediated inhibition. The GoC circuit therefore plays a central role in determining how sensory and motor information is transformed as it flows through the cerebellar input layer. Recent work has shown that GCs are activated when animals perform active behaviours, but the underlying mechanisms remain poorly understood. Norepinephrine (NE), also known as noradrenaline, is a powerful modulator of network function during active behavioral states and the axons of NE-releasing neurons in the locus coeruleus innervate the cerebellar cortex. Here we show that NE hyperpolarizes the GoC membrane potential, decreases spontaneous firing and reduces the gain of the spike frequency versus input-current relationship. The GoC membrane hyperpolarization can be mimicked with an 2-noradrenergic agonist, inhibited with a specific 2 antagonist and is abolished when G protein-coupled inwardly-rectifying potassium (GIRK) channels are blocked. Moreover, NE reduces the effective electrical coupling between GoCs through a persistent sodium current (INaP)-dependent mechanism. Our results suggest that NE controls the gain of the GoC inhibitory circuit by modulating membrane conductances that act to reduce membrane excitability and decrease electrical coupling. These mechanisms appear configured to reduce the level of GoC inhibition onto GCs during active behavioural states.

neuroscience↗