Biology subjects

Venturino, A.

Publications and source records attributed to Venturino, A..

9 recordsLinked to original sources

bioRxiv2026

Nanoscale remodeling of synaptic glutamate receptors and calcium channels in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy and remains drug-resistant in approximately one-third of patients, for whom surgical resection of the epileptogenic zone is currently the most effective treatment option. One strategy to improve therapeutic outcomes involves identifying the molecular mechanisms and key regulators underlying synaptic function. Although altered glutamatergic neurotransmission is considered a major contributor to epileptic hyperexcitability, the nanoscale organization of key synaptic proteins in the human epileptic cortex is still not well characterized. In particular, it remains unclear whether pre- and postsynaptic proteins undergo synapse-type-specific remodeling in TLE. Here, we used high-resolution freeze-fracture replica immunolabeling to map the nanoscale organization of postsynaptic AMPA receptors (AMPARs) and presynaptic P/Q-type voltage-gated calcium channels (CaV2.1) in glutamatergic synapses of cortical layers II/III of surgically resected human tissue. We examined perilesional, cytologically unremarkable, non-epileptogenic cortical tissue obtained from patients undergoing tumor resection (52-63 years; two female and three male patients) and compared these data with cortical samples from patients with refractory TLE (22-53 years; two female and four male patients). To assess whether pathological remodeling differs across synapse populations, we analyzed both excitatory dendritic spine and shaft synapses. We found a robust, highly consistent increase in AMPAR density at both spine and shaft synapses in TLE patients indicating enhanced postsynaptic excitatory signaling. However, AMPAR spatial reorganization differed between synapse types. Monte Carlo simulations demonstrated that spine synapses largely preserved a random receptor distribution without a significant clustering pattern, whereas shaft synapses exhibited a redistribution from clustering toward random receptor arrangements together with reduced center-preference within the postsynaptic density. In contrast, presynaptic CaV2.1 remodeling was more variable and predominantly associated with excitatory spine synapses. TLE spine synapses exhibited an overall increase in CaV2.1 density together with significantly larger and more numerous CaV2.1 nanoclusters within the active zone. This difference was particularly pronounced in male patients. In comparison, shaft synapses displayed only minor presynaptic alterations. CaV2.1 channels remained highly clustered under both control and epileptic conditions, indicating preservation of core active-zone organizational features despite disease-associated nanoscale remodeling. Together, these findings provide direct ultrastructural support that pathological plasticity in human TLE involves an overall increase in excitatory postsynaptic responsiveness and a target cell-specific increase of excitatory release probability at cortical synapses.

neuroscience↗

bioRxiv2026

Genome Assembly of the Endangered Patagonian Deer Hippocamelus bisulcus (huemul): The First Nuclear Genome for the Genus Hippocamelus

The huemul (Hippocamelus bisulcus) is an endangered cervid endemic to the Andean-Patagonian region of South America, where it persists in small, fragmented populations. The lack of a reference genome has constrained genomic approaches to huemul conservation and evolutionary research. Despite moderate theoretical coverage (~22.8x), Oxford Nanopore long reads yielded the first highly contiguous and nearly complete nuclear genome assembly for H. bisulcus. The 2.50-Gb assembly achieved a contig N50 of 8.75 Mb, 99.0% BUSCO completeness, an estimated k-mer completeness of 95.63%, and an ONT k-mer-based QV estimate of 48.11. Reference-guided scaffolding against the white-tailed deer (Odocoileus virginianus) genome organized 94% of the assembly into 36 chromosome-scale pseudomolecules (34 autosomes, X, and Y; scaffold N50 = 68.56 Mb). Repeat annotation identified 38.09% of the assembly as repetitive, dominated by LINEs, consistent with other cervid genomes. Coordinate-based annotation transfer with LiftOn identified 20,042 protein-coding genes, with 95.9% BUSCO completeness in the representative predicted proteome. We also assembled a complete circular mitochondrial genome of 16,405 bp containing the expected 37-gene complement in the conserved vertebrate arrangement. Nuclear and mitochondrial phylogenies placed H. bisulcus within Odocoileini (Capreolinae), while the mitochondrial analysis recovered H. bisulcus and the Andean deer H. antisensis as a maximally supported sister pair. Comparative analysis across nine Cervidae proteomes assigned 98.8% of the representative H. bisulcus proteins to orthogroups shared with at least one other species, indicating broad recovery of the conserved cervid protein repertoire. This study provides the first nuclear genome for the South American genus Hippocamelus and the first nuclear and mitochondrial genomic resources for H. bisulcus, establishing a foundational framework for population genomics, conservation management, and evolutionary studies of this emblematic Patagonian deer.

genomics↗

bioRxiv2025

Corticosterone-linked microglial activity underpins sexually dimorphic neuroplasticity after ketamine anesthesia.

Anesthesia recovery is critical for resuming normal physiological and neuronal functions; however, the mechanisms involved remain elusive. Here, we identify a female-selective corticosterone-mediated microglia-neuron interaction in vivo during ketamine anesthesia recovery, absent in males. This microglia-neuron interaction induces plastic and functional neuronal changes, as evidenced by increased spine density and mEPSC frequency, which is occluded upon microglia depletion. We show that this process is driven through upregulation of the stress-responsive co-chaperone Fkbp5 mRNA and its protein, FKBP51, in female microglia. Fkbp5/FKBP51 is a key intermediary in a corticosteroid-induced stress response, and its involvement points towards a critical interface between endocrine signaling and microglia. Thus, to counteract the observed KXA-mediated corticosterone increase in the blood, we remove the primary source of corticosterone through adrenalectomy. Close microglia-neuron interaction was absent, but was reinstated after corticosterone injection. Our findings offer a new mechanism of microglia-mediated neuronal plasticity during anesthesia recovery, which is mediated through corticosterone, enhancing our understanding of sex differences in brain function.

neuroscience↗

bioRxiv2025

Flickering white light stimulation at 60 Hz induces strong, widespread neural entrainment and synchrony in healthy subjects

BackgroundWhile the effects of 40 Hz externally-induced neural entrainment have been extensively described, little is known about 60 Hz entrainment in humans. Given the role of 60 Hz in cognition, neuroplasticity and neuropsychiatric disorders, this warrants further investigation. ObjectivesThis pilot study characterizes, for the first time, the neural and somatic response to 60 Hz light entrainment in healthy volunteers, over a 3 week-period. MethodsFourteen volunteers were randomized to receive either 60 Hz flickering white light or constant light as sham (30-min sessions, for 3 weeks, 5 days a week). Neural entrainment was assessed with EEG on days 1, 5 and 19. Salivary cortisol and C-reactive protein (CRP) levels, measured with ELISA, assessed the somatic response to stimulation. Side effects and well-being were monitored via questionnaires. Results60 Hz flickering light induced a strong neural entrainment across visual, parietal, temporal and frontal cortex. The signal was highly synchronous but declined significantly by day 19 compared to day 1, indicating neural habituation. Cortisol and CRP salivary levels were unchanged and the stimulation was well tolerated. ConclusionsTo the best of our knowledge this is the first study to characterize both the neural and the somatic response to flickering light over 3 weeks. The observed neural habituation suggests that neuroplasticity could be induced with repeated stimulations over 3 weeks. 60 Hz stimulation for modulating brain activity and induce neuroplasticity has implications for our basic understanding of brain physiology as well as treatment of psychiatric disorders.

neuroscience↗

bioRxiv2024

Hydrocarbon effects on cell survival and antioxidant system of breast tumorigenic and non-tumorigenic cells.

Over the last decades, environmental pollution with polycyclic aromatic hydrocarbons (PAH) has risen due to human development and industrial activities. The consequences of potential contamination with oil or any of its components must be evaluated. Here, we faced the effects on cell growth and detoxification that might arise from the exposure to hydrocarbons sourced from contaminated waters. MCF-7 and MDA-MB-231 human breast cancer cells and/or MCF-10A epithelial non-tumorigenic cells were exposed to water-accommodated oil fraction (WAF) or anthracene as a PAH currently found in the environment to evaluate clonogenicity, viability, GST and CAT activities. WAF decreased MDA-MB-231 cells clonogenicity and MDA-MB-231 and MCF-7 cells viability. Anthracene significantly reduced non-tumorigenic cells viability and clonogenicity, without affecting the survival of tumorigenic cells. Both tumorigenic cells responded mainly by activating the antioxidant system through the increment of CAT when exposed to low concentrations of WAF. In both cell lines, WAF also increased GST. Anthracene exposure significantly decreased CAT activity of the three cell lines evaluated. GST activity decreased 38% after 28 {micro}M anthracene exposure in MDA-MB-231 cells (p<0.05) and 15, 17 and 21% after 7 (p<0.05), 14 and 28 {micro}M (p<0.01) in MCF-10A cells, while in MCF-7 cells 28 {micro}M anthracene increased GST activity by 75% (p<0.001). We conclude that the sensitivity of cells to the different contaminants evaluated is affected by the degree of cellular tumorigenicity and exposure to WAF or anthracene may exacerbate malignant conditions. The integration of multiple parameters, analyzed through multivariate methods, offers a comprehensive evaluation of toxicant effects. HIGHLIGHTSO_LIWAF and anthracene affect tumorigenic mammary cells viability and clonogenicity C_LIO_LINon tumorigenic mammary cells show more sensitivity to anthracene exposure C_LIO_LIWAF activates antioxidant and detoxicant system in tumorigenic mammary cells C_LIO_LIAnthracene decreased CAT activity of tumorigenic and non-tumorigenic mammary cells C_LIO_LIAnthracene affected GST activity of tumorigenic and non-tumorigenic mammary cells C_LI

cell biology↗

bioRxiv2024

Microglia determine an immune-challenged environment and facilitate ibuprofen action in human retinal organoids.

Prenatal immune challenges pose significant risks to human embryonic brain and eye development. However, we still lack knowledge about the safe usage of anti-inflammatory drugs during pregnancy. While human induced pluripotent stem cells (hIPSC)-derived brain organoid models have started to explore functional consequences upon viral stimulation, these models commonly lack microglia. Yet, microglia are susceptible to and promote inflammation and will influence the effects. Here, we generate hIPSC-derived microglia precursor cells and assemble them into retinal organoids to dissect their interplay with the developing nervous system and expose them to the immunostimulant poly(I:C). We first identified successful hIPSC-derived microglia (iMG) integration into the retinal organoid at the time when the outer plexiform layer forms. To improve ganglion cell surveillance, we adapted the retinal organoid model and found that the ganglion cell number significantly decreased only with iMG presence. While poly(I:C) exposure alters the iMG phenotype, it does not hinder their interaction with ganglion cells. Furthermore, iMG significantly enhances the supernatants inflammatory secretome and increases retinal cell proliferation. Simultaneous exposure with the non-steroidal anti-inflammatory drug (NSAID) ibuprofen dampens the poly(I:C)-mediated changes of the iMG phenotype and ameliorates cell proliferation. Remarkably, while poly(I:C) disrupts neuronal calcium dynamics independent of iMG, ibuprofen rescues this effect only if iMG are present. This effect depends on cyclooxygenase 1 in microglia and cyclooxygenase 2, common NSAID targets. These findings underscore the importance of microglia in the context of prenatal immune challenges and provide insight into the mechanisms by which ibuprofen exerts its protective effects during embryonic development.

neuroscience↗

bioRxiv2022

Uncovering brain tissue architecture across scales with super-resolution light microscopy

Mapping the complex and dense arrangement of cells and their connectivity in brain tissue demands nanoscale spatial resolution imaging. Super-resolution optical microscopy excels at visualizing specific molecules and individual cells but fails to provide tissue context. Here we developed Comprehensive Analysis of Tissues across Scales (CATS), a technology to densely map brain tissue architecture from millimeter regional to nanoscopic synaptic scales in diverse chemically fixed brain preparations, including rodent and human. CATS leverages fixation-compatible extracellular labeling and advanced optical readout, in particular stimulated-emission depletion and expansion microscopy, to comprehensively delineate cellular structures. It enables 3D-reconstructing single synapses and mapping synaptic connectivity by identification and tailored analysis of putative synaptic cleft regions. Applying CATS to the hippocampal mossy fiber circuitry, we demonstrate its power to reveal the systems molecularly informed ultrastructure across spatial scales and assess local connectivity by reconstructing and quantifying the synaptic input and output structure of identified neurons.

neuroscience↗

bioRxiv2022

A systematic characterization of intrinsically formed microglia-like cells during retinal organoid differentiation.

Brain organoids differentiated from human induced pluripotent stem cells provide a unique opportunity to investigate the development, organization and connectivity of neurons in a complex cellular environment. However, organoids usually lack microglia, brain-resident immune cells which are both present in the early human embryonic brain and participate in neuronal circuit development. Here, we find that microglia innately develop in unguided retinal organoid differentiation between week 3 and 4 in 2.5D culture and appear later in floating, non-pigmented, 3D-cystic compartments. We enriched for cystic structures using a low-dosed BMP4 application and performed mass spectrometry, thus defining the protein composition of microglia-containing compartments. We found that cystic compartments expressed both mesenchymal and epithelial markers with microglia enriched in the mesenchymal region. Interestingly, microglia-like cells started to express the border-associated macrophage marker CD163. The preferential localization of human microglia to a mesenchymal compartment provides insight into the behavior and migration of microglia. The model will ultimately allow detailed study of these enigmatic cells and how they enter and distribute within the human brain.

neuroscience↗

bioRxiv2021

Microglial MorphOMICs unravel region- and sex-dependent morphological phenotypes from postnatal development to degeneration

Microglia contribute to tissue homeostasis in physiological conditions with environmental cues influencing their ever-changing morphology. Strategies to identify these changes usually involve user-selected morphometric features, which, however, have proved ineffective in establishing a spectrum of context-dependent morphological phenotypes. Here, we have developed MorphOMICs, a topological data analysis approach to overcome feature-selection-based biases and biological variability. We extracted a spatially heterogeneous and sexually-dimorphic morphological phenotype for seven adult brain regions, with ovariectomized females forming their own distinct cluster. This sex-specific phenotype declines with maturation but increases over the disease trajectories in two neurodegeneration models, 5xFAD and CK-p25. Females show an earlier morphological shift in the immediately-affected brain regions. Finally, we demonstrate that both the primary- and the short terminal processes provide distinct insights to morphological phenotypes. MorphOMICs maps microglial morphology into a spectrum of cue-dependent phenotypes in a minimally-biased and semi-automatic way.

neuroscience↗