Biology subjects

Capogna, M.

Publications and source records attributed to Capogna, M..

7 recordsLinked to original sources

bioRxiv2024

Glioblastoma cells imitate neuronal excitability in humans

BackgroundGlioblastomas are renowned for their pronounced intratumoral heterogeneity, characterized by a diverse array of plastic cell types. However, the physiological and transcriptomic features of the cells residing in the invasive leading edge (LE), including both neurons and glioblastoma cells (GBCs), remain unclear, challenging our comprehension of the glioblastoma pathophysiology. MethodsTo elucidate molecular and morphophysiological features of LE cells, we established an experimental workflow enabling the investigation of GBCs and neurons within cancer-infiltrated organotypic tissue specimens from the same patients. With this approach, we characterized the electrophysiological properties of cells in the neocortical tumor LE (LE cells). We further performed single-cell Patch-seq experiments, enabling transcriptomic analysis of electrophysiologically recorded LE cells. ResultsUpon depolarization, 58% of LE cells exhibited aberrant action potentials (aAPs). Electrophysiological assessment showed that a subset of GBCs generated aAPs, with no significant differences in aAP properties compared to LE neurons. Transcriptomic analysis of 144 LE cells revealed four transcriptomic clusters, including two GBC populations and two neuronal populations. LE GBCs exhibited diverse cellular states, including mesenchymal-like, astrocyte-like, neural progenitor-like, and oligodendrocyte-precursor cell-like phenotypes. Notably, LE GBCs exhibiting aAPs displayed reduced mitotic pathway activity and developmental regulatory ion channel CaV1.2. Cell-cell interaction analysis illustrates a higher signaling interaction between aAP LE cells compared to no-aAP LE cells. ConclusionIn summary, we find comparable electrical properties between neurons and a subset of GBCs in the leading edge, suggesting an active electrophysiological role of GBCs in the tumors pathophysiology. Key PointsO_LIHuman organotypic slice cultures enable long-term functional investigation of glioblastoma cells. C_LIO_LIGBCs and neurons in the LE exhibit similar aAPs. C_LIO_LILE GBCs display heterogeneous cellular states, with reduced proliferation signaling in aAP GBCs. C_LI Importance of studyThis study sheds light on the diverse pathophysiological and molecular features of cells in the neocortical infiltration zone of glioblastoma. By utilizing in vitro organotypic human brain slice cultures, a reliable platform for longitudinal observation, we unveiled the dichotomy of the electrical properties of LE cells. More than half of LE cells display aAP, contradicting findings from cultured tumor cells and animal models. Patch-seq analysis confirmed that both GBCs and neurons in the LE generate aAPs with indistinguishable electrical properties. aAP GBCs showed higher cell-cell interactions. We find aAP GBCs to express reduced proliferation signaling compared to no-aAP GBCs, suggesting a non-dividing and potentially more plastic cell state. These findings point to the electrical-active GBCs as an important attribute of the LE, linking the electrophysiological properties with functional implications, and implicate an active role of electrophysiological changes of GBCs in tumor pathophysiology.

cancer biology↗

bioRxiv2024

A combinatory genetic strategy for targeting neurogliaform neurons in the mouse basolateral amygdala

The mouse basolateral amygdala (BLA) contains various GABAergic interneuron subpopulations, which have distinctive roles in the neuronal microcircuit controlling numerous behavioral functions. In mice, roughly 15% of the BLA GABAergic interneurons express neuropeptide Y (NPY), a reasonably characteristic marker for neurogliaform cells (NGFCs) in cortical-like brain structures. However, genetically labeled putative NPY-expressing interneurons in the BLA yield a mixture of interneuron subtypes besides NGFCs. Thus, selective molecular markers are lacking for genetically accessing NGFCs in the BLA. Here, we validated the NGFC-specific labeling with a molecular marker, neuron-derived neurotrophic factor (NDNF), in the mouse BLA, as such specificity has been demonstrated in the neocortex and hippocampus. We characterized genetically defined NDNF-expressing (NDNF+) GABAergic interneurons in the mouse BLA by combining the Ndnf-IRES2-dgCre-D transgenic mouse line with viral labeling, immunohistochemical staining, and in vitro electrophysiology. We found that BLA NDNF+ GABAergic cells mainly expressed NGFC neurochemical markers NPY and reelin (Reln) and exhibited small round soma and dense axonal arborization. Whole-cell patch clamp recordings indicated that most NDNF+ interneurons showed late spiking and moderate firing adaptation. Moreover, [~]81% of BLA NDNF+ cells generated retroaxonal action potential after current injections or optogenetic stimulations, frequently developing into persistent barrage firing. Optogenetic activation of the BLA NDNF+ cell population yielded both GABAA- and GABAB receptor-mediated currents onto BLA pyramidal neurons (PNs). We demonstrate a combinatory strategy combining the NDNF-cre mouse line with viral transfection to specifically target adult mouse BLA NGFCs and further explore their functional and behavioral roles.

neuroscience↗

bioRxiv2023

Inhibitory fear memory engram in the mouse central lateral amygdala

Engrams are cellular substrates of memory traces that have been identified in various brain areas, including the amygdala. Most engrams identified so far are formed by excitatory, glutamatergic neurons. However, little attention has been paid to defining GABAergic inhibitory engrams. Here, we report an inhibitory engram in the central lateral amygdala (CeL), a crucial area for Pavlovian fear conditioning. This engram is primarily composed of GABAergic somatostatin-expressing (SST+) and to a lesser extent of protein kinase C-{delta}-expressing [PKC-{delta}(+)] neurons. Fear memory is accompanied by a preferential enhancement of mIPSC frequency onto PKC-{delta}(+) neurons as well as a general increment of amplitude. Moreover, non-engram cells exhibit higher mIPSC frequency than engram cells. The inhibition of the CeL GABAergic engram disinhibits the activity of engram-targeted areas and increases selectively the encoded fear expression. Our data defines the behavioral function of an engram formed exclusively by GABAergic inhibitory neurons in the mammalian CNS.

neuroscience↗

bioRxiv2023

Differential activity patterns in the upper and lower blade of the dentate gyrus

The dentate gyrus is considered the first stage in the trisynaptic circuit of the hippocampus. Granule cells of the dentate gyrus fire very sparsely with a low probability of overlapping patterns of active neurons. This characteristic supports the most prevalent view of the dentate gyrus function as that of a pattern separator: to generate dissimilar neuronal representations from overlapping input states that represent similar but not identical environments. However, there are two distinct granule cell blades that have been shown to have different activity patterns: the upper blade and the lower blade. These may support different purposes, but their differential function is not well understood. Here we have recorded calcium imaging data from both the upper and the lower blade of the dentate gyrus from two mice (the upper blade from one, the lower blade from the other), while they perform a simple decision-making task. We found that only the lower blade encodes subjective emotional response while the upper blade preferentially encodes the actual response. Importantly, we found that correlations between cells carried more information about these two behavioural variables than individual firings, suggesting that neuron correlations encode here important information above and beyond individual unit activity.

neuroscience↗

bioRxiv2023

Non-Hebbian plasticity produces long-lasting associative memories

The dominant models of learning and memory, such as Hebbian plasticity, propose that experiences are transformed into memories through input-specific synaptic plasticity at the time of learning. However, synaptic plasticity is neither strictly input specific nor restricted to the time of its induction. The impact of such forms of non-Hebbian plasticity on memory has been difficult to test, hence poorly understood. Here, we demonstrate that synaptic manipulations can deviate from the Hebbian model of learning, yet produce a lasting memory. First, we established a weak associative conditioning protocol in mice, where optogenetic stimulation of sensory thalamic input to the amygdala was paired with a footshock, but no detectable memory was formed. However, when the same input was potentiated minutes before or after, or even 24 hours later, the associative experience was converted to a lasting memory. Importantly, potentiating an independent input to the amygdala minutes but not 24 hours after the pairing produced a lasting memory. Thus, our findings suggest that the process of transformation of a transient experience into a memory is neither restricted to the time of the experience nor to the synapses triggered by it; instead, it can be influenced by past and future events.

neuroscience↗

bioRxiv2020

Dopaminergic neuromodulation of spike timing dependent plasticity in mature adult rodent and human cortical neurons

Synapses in the cerebral cortex constantly change and this dynamic property regulated by the action of neuromodulators such as dopamine (DA), is essential for reward learning and memory. DA modulates spike-timing-dependent plasticity (STDP), a cellular model of learning and memory, in juvenile rodent cortical neurons. However, it is unknown whether this neuromodulation also occurs at excitatory synapses of cortical neurons in mature adult mice or in humans. Cortical layer V pyramidal neurons were recorded with whole cell patch clamp electrophysiology and an extracellular stimulating electrode was used to induce STDP. DA was either bath-applied or optogenetically released in slices from mice. Classical STDP induction protocols triggered non-Hebbian excitatory synaptic depression in the mouse or no plasticity at human cortical synapses. DA reverted long term synaptic depression to baseline in mouse or elicited long term synaptic potentiation in human cortical synapses. Furthermore, when DA was applied during a STDP protocol it depressed presynaptic inhibition in the mouse but not in the human cortex. Thus, DA modulates excitatory synaptic plasticity differently in human versus mouse cortex. The data strengthens the importance of DA in gating cognition in humans, and may inform on therapeutic interventions to recover brain function from diseases.

neuroscience↗

bioRxiv2020

TRACE: An unbiased method to permanently tag transiently activated inputs

A fundamental interest in circuit analysis is to parse out the synaptic inputs underlying a behavioral experience. Toward this aim, we have devised an unbiased strategy that specifically labels the afferent inputs that are activated by a defined stimulus in an activity-dependent manner. We validated this strategy in four brain areas receiving known sensory inputs. This strategy, as demonstrated here, accurately identifies these inputs.

neuroscience↗