Search Results (156)

Developing robust methods to differentiate pluripotent stem cells (PSCs) into specific neuronal subtypes is crucial for advancing neuroscience research, including disease modelling and regenerative medicine. Research in this area has primarily focused on generating and studying excitatory neurons, often in co-culture with primary astrocytes to support maturation. Due to the shared ectodermal lineage of these cell types, any mesoderm derived cells, such as microglia, are absent using traditional methods of culture. To more accurately model the intricate complexity of the brain and its normal neuronal physiology, it is important to incorporate other critical neural subtypes, such as inhibitory interneurons and various glial cells. This review highlights recent progress in using transcription factor-based in vitro differentiation strategies to generate these diverse neural populations. A major advantage of this approach is the ability to rapidly produce highly specific cell types in a controlled manner, allowing for the precise seeding of cells at defined anatomical and physiological ratios. This controlled methodology enables the creation of more accurate and reproducible in vitro models, including two-dimensional (2D) and three-dimensional (3D) cultures and organoids, thereby moving beyond the limitations of random differentiation from neuronal progenitor cells. Despite these advances, key challenges remain, including reproducibility between pluripotent stem cell lines, off-target transcriptional effects of exogenous factors, and incomplete phenotypic maturation of derived cells. Addressing these constraints is essential for translating transcription factor-based approaches into robust and clinically relevant neural models. Full article

Neurodevelopmental disorders (NDDs), including autism spectrum disorder, intellectual disability, and attention deficit hyperactivity disorder, are increasingly recognized as disorders of early brain construction arising from defects in neural stem and progenitor cell (NSPC) proliferation. NSPCs are responsible for generating the diverse neuronal and glial lineages that establish cortical architecture and neural circuitry; thus, their expansion must be tightly coordinated by intrinsic cell cycle regulators and extrinsic niche-derived cues. Disruption of these mechanisms—through genetic mutations, epigenetic dysregulation, or environmental insults—can perturb the balance between NSPC self-renewal and differentiation, resulting in aberrant brain size and connectivity. Recent advances using animal models and human pluripotent stem cell-derived brain organoids have identified key signaling pathways, including Notch, Wnt, SHH, and PI3K–mTOR, as central hubs integrating proliferative cues, while transcriptional and chromatin regulators such as PAX6, CHD8, SETD5, and ANKRD11 govern gene expression essential for proper NSPC cycling. Furthermore, prenatal exposure to teratogens such as Zika virus infection, valproic acid, or metabolic stress in phenylketonuria can recapitulate proliferation defects and microcephaly, underscoring the vulnerability of NSPCs to environmental perturbation. This review summarizes emerging insights into the molecular and cellular mechanisms by which defective NSPC proliferation contributes to NDD pathogenesis, highlighting convergence among genetic and environmental factors on cell cycle control. A deeper understanding of these pathways may uncover shared therapeutic targets to restore neurodevelopmental trajectories and mitigate disease burden. Full article

Animal models have been pivotal in uncovering the orexin (hypocretin) system as the fulcrum of sleep–wake regulation and in shaping therapeutic discovery for narcolepsy. Early canine and murine models established that orexin loss underlies narcolepsy type 1, while conditional and receptor-specific manipulations refined mechanistic insight. However, current paradigms capture only fragments of the human phenotype, often exaggerating cataplexy and under-representing narcolepsy type 2. Here, we follow the evolution of narcolepsy modelling from classical knockout and receptor-deficient systems to immune-driven and cell-replacement models, identifying critical translational gaps and proposing strategies to bridge them. We highlight how immune-competent mouse lines, astrocyte-to-neuron reprogramming, and patient-derived hypothalamic organoids bridge pathogenic insight with therapeutic innovation. Integrating these advances with small-molecule OX2R agonists, gene therapy, and multi-omics-based patient stratification defines a roadmap for moving beyond symptomatic control. This review seeks to unify immune, cellular, and computational perspectives to guide the next generation of animal models toward the prevention, repair, and long-term cure of narcolepsy. Full article

Glioblastoma (GB) is one of the most aggressive brain tumors, characterized by high infiltrative capacity that enables tumor cells to invade healthy brain tissue and evade complete surgical resection. This invasiveness contributes to resistance against conventional therapies and a high recurrence rate. Strategies capable of eliminating residual tumor cells are urgently needed. Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA), an FDA- and EMA-approved compound, induces selective accumulation of the photosensitizer protoporphyrin IX (PpIX) in metabolically active tumor cells, enabling targeted cytotoxicity through light activation. A major limitation to its clinical application is the unclear variation in the cytotoxic effect of PDT according to individual tumoral differences. In this study, we propose and validate an in vivo model of patient-derived GB initiating cells (GICs) and brain organoids to test the effects of PDT. First, patient-derived GICs were molecularly characterized by flow cytometry and copy number variation profiling using OncoScan CNV Assays, then co-cultured with human brain organoids to generate a hybrid model recapitulating key aspects of the tumor microenvironment. 5-ALA photodynamic therapy (PDT) efficacy was assessed in vitro by GFP-based viability measurements, LDH release assays, and TUNEL staining. Then, a murine model was generated to study PDT in vivo, based on a heterotopic (renal subcapsular engraftment) xenograft of the GICs-human brain organoid co-culture. PDT was tested in the model; in each subject, one kidney tumoral engraftment was treated and the contralateral served as a control. Immunofluorescence analysis was used to study the cell composition of the brain organoid-tumoral engraftment after PDT, and the effects on non-GIC cells. The antitumoral effect was determined by the degree of cell death analysis with the TUNEL technique. The GICs-brain organoid co-culture resulted in tumoral growth and infiltration both in vitro and in vivo. The pattern of growth and infiltration varied according to the tumoral genetic profile. 5-ALA PDT resulted in a reduction in the number of GICs and an increase in apoptotic cells in all four lines tested in vitro. A correlation was found between the induced phototoxicity in vivo with the molecular typification of GICs cell lines in vitro. There were no changes in the number or distribution of neuronal cells after the application of PDT, while a reduction in active astrocytes was observed. 5-ALA PDT could be effective in eradicating GICs with a heterogeneous molecular profile. The hybrid human-murine model presented here could be useful in investigating adjuvant therapies in GB, under the concept of personalized medicine. Full article

The widespread application of organoids in disease modeling and drug development is significantly constrained by challenges in automated quantitative analysis. In bright-field microscopy images, organoids exhibit complex characteristics, including irregular morphology, blurred boundaries, and substantial scale variations, largely stemming from their dynamic self-organization that mimics in vivo tissue development. Existing convolutional neural network-based methods are limited by fixed receptive fields and insufficient modeling of inter-channel relationships, making them inadequate for detecting such evolving biological structures. To address these challenges, we propose a novel detection head, termed Interactive Dual-Perception Head (IDP-Head), inspired by hierarchical perception mechanisms in the biological visual cortex. Integrated into the RTMDet framework, IDP-Head comprises two bio-inspired components: a Large-Kernel Global Perception Module (LGPM) to capture global morphological dependencies, analogous to the wide receptive fields of cortical neurons, and a Progressive Channel Synergy Module (PCSM) that models inter-channel semantic collaboration, echoing the integrative processing of multi-channel stimuli in neural systems. Additionally, we construct a new organoid detection dataset to mitigate the scarcity of annotated data. Extensive experiments on both our dataset and public benchmarks demonstrate that IDP-Head achieves a 5-percentage-point improvement in mean Average Precision (mAP) over the baseline model, offering a biologically inspired and effective solution for high-fidelity organoid detection. Full article

Thallium (Tl) is a non-essential and highly toxic heavy metal capable of replacing potassium (K⁺) in biological systems, leading to mitochondrial dysfunction, oxidative stress, and inhibition of protein synthesis. In humans, the estimated oral lethal dose ranges from 10 to 15 mg/kg, with acute mortality rates of 6–15% and chronic neurological sequelae in up to 55% of survivors. Environmental releases of thallium of up to 5000 metric tons annually from industrial and mining activities, combined with its high oral bioavailability and nonspecific multisystemic symptoms, underscore the urgent need for more effective therapeutic strategies. This review summarizes current evidence on Tl toxicity, including its mechanisms of action, clinical manifestations, and available treatments. It emphasizes the strategic selection of biological models: simple organisms such as Caenorhabditis elegans and Drosophila melanogaster enable high-throughput screening and early biomarker detection; zebrafish (Danio rerio) provide vertebrate-level evaluation of multi-organ effects; and rodent models offer systemic toxicokinetic and therapeutic validation. Human-derived organoids and induced pluripotent stem cell (iPSC) systems recreate tissue-specific microenvironments, allowing translational assessment of mitochondrial, neuronal, and cardiac toxicity. Integrating these models within a tiered and complementary framework, alongside environmental and clinical surveillance, can accelerate the development of targeted treatments and strengthen public health responses to Tl exposure. Full article

Organoids allow to model healthy and diseased human tissues. and have applications in developmental biology, drug discovery, and cell therapy. Traditionally cultured in immersion/suspension, organoids face issues like lack of standardization, fusion, hypoxia-induced necrosis, continuous agitation, and high media volume requirements. To address these issues, we developed an air–liquid interface (ALi) technology for culturing organoids, termed AirLiwell. It uses non-adhesive microwells for generating and maintaining individualized organoids on an air–liquid interface. This method ensures high standardization, prevents organoid fusion, eliminates the need for agitation, simplifies media changes, reduces media volume, and is compatible with Good Manufacturing Practices. We compared the ALi method to standard immersion culture for midbrain organoids, detailing the process from human pluripotent stem cell (hPSC) culture to organoid maturation and analysis. Air–liquid interface organoids (3D-ALi) showed optimized size and shape standardization. RNA sequencing and immunostaining confirmed neural/dopaminergic specification. Single-cell RNA sequencing revealed that immersion organoids (3D-i) contained 16% fibroblast-like, 23% myeloid-like, and 61% neural cells (49% neurons), whereas 3D-ALi organoids comprised 99% neural cells (86% neurons). Functionally, 3D-ALi organoids showed a striking electrophysiological synchronization, unlike the heterogeneous activity of 3D-i organoids. This standardized organoid platform improves reproducibility and scalability, demonstrated here with midbrain organoids. The use of midbrain organoids is particularly relevant for neuroscience and neurodegenerative diseases, such as Parkinson’s disease, due to their high incidence, opening new perspectives in disease modeling and cell therapy. In addition to hPSC-derived organoids, the method’s versatility extends to cancer organoids and 3D cultures from primary human cells. Full article

Miller–Dieker Syndrome (MDS) is a rare neurodevelopmental disorder caused by a heterozygous deletion of approximately 26 genes within the MDS locus of human chromosome 17. MDS, which affects 1 in 100,000 babies, can lead to a range of phenotypes, including lissencephaly, severe neurological defects, distinctive facial abnormalities, cognitive impairments, seizures, growth retardation, and congenital heart and liver abnormalities. One hallmark feature of MDS is an unusually smooth brain surface due to abnormal neuronal migration during early brain development. Several genes located within the MDS locus have been implicated in the pathogenesis of MDS, including PAFAH1B1, YWHAE, CRK, and METTL16. These genes play a role in the molecular and cellular pathways that are vital for neuronal migration, the proper development of the cerebral cortex, and protein translation in MDS. Improved model systems, such as MDS patient-derived organoids and multi-omics analyses indicate that WNT/β-catenin signaling, calcium signaling, S-adenosyl methionine (SAM) homeostasis, mammalian target of rapamycin (mTOR) signaling, Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling, and others are dysfunctional in MDS. This review of MDS integrates details at the clinical level alongside newly emerging details at the molecular and cellular levels, which may inform the development of novel therapeutic strategies for MDS. Full article

Brain organoid technology has seen significant development in recent years. This self-organized, three-dimensional, organ-oriented brain tissue model can recapitulate the process of neurogenesis and consists of diverse cell types and cellular architecture. Transplanting brain organoids in vivo could be a potential tool from bench to clinical research and has been studied for many purposes. To investigate and summarize the methodology, findings, and applications of this novel technique from current evidence, we conducted this systematic review by searching PubMed and the Embase databases for the literature ranging from 2013 to 2024. A total of 480 articles were identified, and 24 of them met the inclusion criteria. The results revealed that brain organoid transplantation had promising graft survival, neural proliferation, differentiation, and maturation, axonal growth, and functional integration into the host neuronal circuit, and has been applied to multiple applications, such as therapeutic usage, cell study platforms, and disease modeling. However, heterogeneity among studies, some significant challenges, and ethical issues remain to be considered. This comprehensive review will provide an update of what is known about this powerful, innovative method and discuss some practical aspects for future research. Full article

The study of neuronal electrical activity and spatial organization is essential for uncovering the mechanisms that regulate neuronal electrophysiology and function. Mathematical models have been utilized to analyze the structural properties of neuronal networks, predict connectivity patterns, and examine how morphological changes impact neural network function. In this study, we aimed to explore the role of the actin cytoskeleton in neuronal signaling via primary cilia and to elucidate the role of the actin network in conjunction with neuronal electrical activity in shaping spatial neuronal formation and organization, as demonstrated by relevant mathematical models. Our proposed model is based on the polygamma function, a mathematical application of ramification, and a geometrical definition of the actin cytoskeleton via complex numbers, ring polynomials, homogeneous polynomials, characteristic polynomials, gradients, the Dirac delta function, the vector Laplacian, the Goldman equation, and the Lie bracket of vector fields. We were able to reflect the effects of neuronal electrical activity, as modeled by the Van der Pol equation in combination with the actin cytoskeleton, on neuronal morphology in a 2D model. In the next step, we converted the 2D model into a 3D model of neuronal electrical activity, known as a core-shell model, in which our generated membrane potential is compatible with the neuronal membrane potential (in millivolts, mV). The generated neurons can grow and develop like an organoid brain based on the developed mathematical equations. Furthermore, we mathematically introduced the signal transduction of primary cilia in neurons. Additionally, we proposed a geometrical model of the neuronal branching pattern, which we described as ramification, that could serve as an alternative mathematical explanation for the branching pattern emanating from the neuronal soma. In conclusion, we highlighted the relationship between the actin cytoskeleton and the signaling processes of primary cilia. We also developed a 3D model that integrates the geometric organization unique to neurons, which contains soma and branches, such that the mathematical model represents the interaction between the actin cytoskeleton and neuronal electrical activity in generating action potentials. Next, we could generalize the model into a cluster of neurons, similar to an organoid brain model. This mathematical framework offers promising applications in artificial intelligence and advancements in neural networks. Full article

Pediatric high-grade gliomas (pHGGs), particularly diffuse midline gliomas (DMGs), are among the most lethal brain tumors due to poor survival and resistance to therapies. DMGs possess a distinct genetic profile, primarily driven by hallmark mutations such as H3K27M, ACVR1, and PDGFRA mutations/amplifications and TP53 inactivation, all of which contribute to tumor biology and therapeutic resistance. Developing physiologically relevant preclinical models that replicate both tumor biology and the tumor microenvironment (TME) is critical for advancing effective treatments. This review highlights recent progress in in vitro, ex vivo, and in vivo models, including patient-derived brain organoids, genetically engineered mouse models (GEMMs), and region-specific midline organoids incorporating SHH, BMP, and FGF2/8/19 signaling to model pontine gliomas. Key genetic alterations can now be introduced using lipofectamine-mediated transfection, PiggyBac plasmid systems, and CRISPR-Cas9, allowing the precise study of tumor initiation, progression, and therapy resistance. These models enable the investigation of TME interactions, including immune responses, neuronal infiltration, and therapeutic vulnerabilities. Future advancements involve developing immune-competent organoids, integrating vascularized networks, and applying multi-omics platforms like single-cell RNA sequencing and spatial transcriptomics to dissect tumor heterogeneity and lineage-specific vulnerabilities. These innovative approaches aim to enhance drug screening, identify new therapeutic targets, and accelerate personalized treatments for pediatric gliomas. Full article

Alzheimer’s disease (AD), the leading cause of dementia, remains poorly understood despite decades of intensive research, which continues to hinder the development of effective treatments. As a complex multifactorial disorder, AD lacks a cure to halt the progressive neurodegeneration, and the precise mechanisms underlying its onset and progression remain elusive, limiting therapeutic options. Due to the challenges of studying neuronal cells in vivo, technologies such as clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) and human-induced pluripotent stem cells (hiPSCs) are key for identifying therapeutic targets, although they face technical and ethical hurdles in their early stages. CRISPR/Cas9 and hiPSCs are promising for disease modeling and therapy, but off-target effects and the complexity of gene editing in the brain limit their use. CRISPR technology enables specific genetic modifications in key AD-related genes, such as APP, PSEN1, PSEN2, and APOE, providing valuable insights into disease mechanisms. iPSC-derived neurons, astrocytes, microglia, and 3D organoids can recapitulate key aspects of human AD pathology, but they do not fully replicate the complexity of the human brain, limiting clinical applicability. These technologies advance studies of amyloid processing, tau aggregation, neuroinflammation, and oxidative stress, yet translating them into clinical therapies remains challenging. Despite the promise of CRISPR/Cas9 and iPSCs for precision medicine, gaps in knowledge about their long-term safety and efficacy must be addressed before clinical implementation. Full article

Background: The development of cerebral organoids created from human pluripotent stem cells in 3D culture may greatly improve the discovery of neuropsychiatric medicines. Methods: In the current study we differentiated neural organoids from a human pluripotent stem cell line in vitro, recorded the development of neurophysiological activity using multielectrode arrays (MEAs) and characterized the neuropharmacology of synaptic signaling over 8 months in vitro. In addition, we investigated the ability of these organoids to display epileptiform activity in response to a convulsant agent and the effects of antiseizure medicines to inhibit this abnormal activity. Results: Single and bursts of action potentials from individual neurons and network bursts were recorded on the MEA plates and significantly increased and became more complex from week 7 to week 30, consistent with neural network formation. Neural spiking was reduced by the Na channel blocker tetrodotoxin but increased by the inhibitor of K_V7 potassium channels XE991, confirming the involvement of voltage-gated sodium and potassium channels in action potential activity. The GABA antagonists bicuculline and picrotoxin each increased the spike rate, consistent with inhibitory synaptic signaling. In contrast, the glutamate receptor antagonist kynurenic acid inhibited the spike rate, consistent with excitatory synaptic transmission in the organoids. The convulsant 4-aminopyridine increased spiking, bursts and synchronized firing, consistent with epileptiform activity in vitro. The anticonvulsants carbamazepine, ethosuximide and diazepam each inhibited this epileptiform neural activity. Conclusions: Together, our data demonstrate that neural organoids form inhibitory and excitatory synaptic circuits, generate epileptiform activity in response to a convulsant agent and detect the antiseizure properties of diverse antiepileptic drugs, supporting their value in drug discovery. Full article

Autism spectrum disorder (ASD) is a neurodevelopmental disorder affecting 1–3% of the population globally. Owing to its multifactorial origin, complex genetics, and heterogeneity in clinical phenotypes, it is difficult to faithfully model ASD. In essence, ASD is an umbrella term for a group of individually rare disorders, each risk gene accounting for <1% of cases, threaded by a set of overlapping behavioral or molecular phenotypes. Validated behavioral tests are considered a gold standard for ASD diagnosis, and several animal models (rodents, pigs, and non-human primates) have traditionally been used to study its molecular basis. These models recapitulate the human phenotype to a varying degree and have been indispensable to preclinical research, but they cannot be used to study human-specific features such as protracted neuronal maturation and cell-intrinsic attributes, posing serious limitations to translatability. Human stem cell-based models, both as monolayer 2D cultures and 3D organoids and assembloids, can circumvent these limitations. Generated from a patient’s own reprogrammed cells, these can be used for testing therapeutic interventions that are more condition and patient relevant, targeting developmental windows where the intervention would be most effective. We discuss some of these advancements by comparing traditional and recent models of ASD. Full article

Arboviruses, transmitted by blood-sucking arthropods, are responsible for significant human and animal diseases, including fever, hemorrhagic fever, and encephalitis, posing a serious threat to global public health. Nevertheless, research on the mechanisms of arbovirus infection and the development of therapeutic interventions has been impeded. This delay is primarily due to the limitations inherent in current in vitro research models, including cell cultures and animal models. The simplicity of cell types and interspecies differences present significant obstacles to advancing our understanding of arbovirus infection mechanisms and the development of effective drugs. Human brain organoids, derived from human pluripotent stem cells or human embryonic stem cells and cultured in three-dimensional systems, more accurately replicate the extensive neuronal cellular diversity and key characteristics of human neurodevelopment. These organoids serve as an ideal model for investigating the intricate interactions between viruses and human hosts, and providing a novel platform for the development of antiviral drugs. In this review, we summarize how brain organoid models complement classical approaches to accelerate research into the infection mechanisms of arboviruses, with a particular focus on the types of neural cells, key factors, and cellular signaling pathways involved in the arbovirus infection of brain organoids that have been reported. Furthermore, we examine the development of brain organoids, address their current limitations, and propose future directions to enhance the application of brain organoids in the study of arboviral infectious diseases. Full article