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Modeling glioblastoma invasion using human brain organoids and single-cell transcriptomics.
BACKGROUND: Glioblastoma (GBM) consists of devastating neoplasms with high invasive capacity, which have been difficult to study in vitro in a human-derived model system. Therapeutic progress is also limited by cellular heterogeneity within and between tumors, among other factors such as therapy resistance. To address these challenges, we present an experimental model using human cerebral organoids as a scaffold for patient-derived GBM cell invasion. METHODS: This study combined tissue clearing and confocal microscopy with single-cell RNA sequencing of GBM cells before and after co-culture with organoid cells. RESULTS: We show that tumor cells within organoids extend a network of long microtubes, recapitulating the in vivo behavior of GBM. Transcriptional changes implicated in the invasion process are coherent across patient samples, indicating that GBM cells reactively upregulate genes required for their dispersion. Potential interactions between GBM and organoid cells identified by an in silico receptor-ligand pairing screen suggest functional therapeutic targets. CONCLUSIONS: Taken together, our model has proven useful for studying GBM invasion and transcriptional heterogeneity in vitro, with applications for both pharmacological screens and patient-specific treatment selection on a time scale amenable to clinical practice.
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Organotypic Cultures of Adult Human Cortex as an Ex vivo Model for Human Stem Cell Transplantation and Validation.
Neurodegenerative disorders are common and heterogeneous in terms of their symptoms and cellular affectation, making their study complicated due to the lack of proper animal models that fully mimic human diseases and the poor availability of post-mortem human brain tissue. Adult human nervous tissue culture offers the possibility to study different aspects of neurological disorders. Molecular, cellular, and biochemical mechanisms could be easily addressed in this system, as well as testing and validating drugs or different treatments, such as cell-based therapies. This method combines long-term organotypic cultures of the adult human cortex, obtained from epileptic patients undergoing resective surgery, and ex vivo intracortical transplantation of induced pluripotent stem cell-derived cortical progenitors. This method will allow the study of cell survival, neuronal differentiation, the formation of synaptic inputs and outputs, and the electrophysiological properties of human-derived cells after transplantation into intact adult human cortical tissue. This approach is an important step prior to the development of a 3D human disease modeling platform that will bring basic research closer to the clinical translation of stem cell-based therapies for patients with different neurological disorders and allow the development of new tools for reconstructing damaged neural circuits.
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Multimodal spatiotemporal monitoring of basal stem cell-derived organoids reveals progression of olfactory dysfunction in Alzheimer's disease.
Olfactory dysfunction (OD) is a highly prevalent symptom and an early sign of neurodegenerative diseases in humans. However, the roles of peripheral olfactory system in disease progression and the mechanisms behind neurodegeneration remain to be studied. Olfactory epithelium (OE) organoid is an ideal model to study pathophysiology in vitro, yet the reliance on 3D culture condition limits continual in situ monitoring of organoid development. Here, we combined impedance biosensors and live imaging for real-time spatiotemporal analysis of OE organoids morphological and physiological features during Alzheimer's disease (AD) progression. The impedance measurements showed that organoids generated from basal stem cells of APP/PS1 transgenic mice had lower proliferation rate than that from wild-type mice. In concert with the biosensor measurements, live imaging enabled to visualize the spatial and temporal dynamics of organoid morphology. Abnormal protein aggregation and accumulation, including amyloid plaques and neurofibrillary tangles, was found in AD organoids and increased as disease progressed. This multimodal in situ bioelectrical measurement and imaging provide a new platform for investigating onset mechanisms of OD, which would shed new light on early diagnosis and treatment of neurodegenerative disease.
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Fate, toxicology and Organ-on-a-chip methodology of nanoplastics in human body.
Nanoplastics (NPs) can cross the human biological barriers, enter the bloodstream, and accumulate in vital organs due to their unique physical and chemical properties. This review provides a detailed explanation of the mechanisms by which NPs cross the air-blood, intestinal, and blood-brain barriers. It provides more insight into how NPs interact with blood components after entering circulation, assesses the cardiovascular toxicity that results, and visually represents how NPs are distributed in human tissues. Traditional static models have significant limitations in simulating the complex physiological microenvironments of the human body. Organ-on-a-chip (OoC) technology is emerging as a novel toxicology tool due to its unique advantages in dynamically reconstructing the vascular microenvironment and biological barriers. This technology allows for a precise characterization of the hemodynamic behavior of NPs and their mechanisms of cross-barrier toxicity. In general, this work offers crucial theoretical and methodological insights to address existing technical issues in assessing the toxicity of emerging environmental contaminants.
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Characterization of HIV-1 Infection in Microglia-Containing Human Cerebral Organoids.
The achievement of an HIV cure is dependent on the eradication or permanent silencing of HIV-latent viral reservoirs, including the understudied central nervous system (CNS) reservoir. This requires a deep understanding of the molecular mechanisms of HIV's entry into the CNS, latency establishment, persistence, and reversal. Therefore, representative CNS culture models that reflect the intercellular dynamics and pathophysiology of the human brain are urgently needed in order to study the CNS viral reservoir and HIV-induced neuropathogenesis. In this study, we characterized a human cerebral organoid model in which microglia grow intrinsically as a CNS culture model to study HIV infection in the CNS. We demonstrated that both cerebral organoids and isolated organoid-derived microglia (oMG), infected with replication-competent HIVbal reporter viruses, support productive HIV infection via the CCR5 co-receptor. Productive HIV infection was only observed in microglial cells. Fluorescence analysis revealed microglia as the only HIV target cell. Susceptibility to HIV infection was dependent on the co-expression of microglia-specific markers and the CD4 and CCR5 HIV receptors. Altogether, this model will be a valuable tool within the HIV research community to study HIV-CNS interactions, the underlying mechanisms of HIV-associated neurological disorders (HAND), and the efficacy of new therapeutic and curative strategies on the CNS viral reservoir.
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A human 3D BBB chip model of acute stroke simulating a reversible penumbra.
Ischemic stroke is a leading cause of mortality and disability worldwide. However, existing models often fail to replicate key aspects of human pathophysiology, particularly blood-brain barrier (BBB) dysfunction and the salvageable ischemic penumbra. We developed a three-dimensional BBB chip model of acute ischemic stroke that reproduces penumbra-like, partially reversible BBB injury. This platform integrates a microfluidic BBB chip (Emulate) with parallel Transwell inserts to facilitate complementary structural, molecular, and functional analyses. Ischemia-like injury was induced using 2.5 μM antimycin A for 1 hour under oxygen-glucose deprivation conditions, followed by medium replacement to simulate reperfusion. Therapeutic hypothermia (33°C) was also applied during the reperfusion phase. The combination of reperfusion and hypothermia resulted in the most pronounced restoration of BBB integrity compared with reperfusion alone. The Emulate chip enabled structural evaluation of endothelial morphology, while the transwell model showed concordant recovery of BBB-related markers, including ZO-1 and VE-cadherin, along with decreased expression of the hypoxia-associated marker HIF-1α. This integrated platform enabled evaluation of BBB injury and recovery under ischemia- and reperfusion-like conditions. Our human cell-based 3D BBB stroke model captures key BBB-related features of penumbra-like injury and provides a human-relevant in vitro platform for investigating stroke pathophysiology and evaluating therapeutic strategies.
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Prodromal Parkinson's disease and the catecholaldehyde hypothesis: Insight from olfactory bulb organotypic cultures.
Parkinson's disease (PD) is a progressive, neurodegenerative disorder with an increasing incidence, unknown etiology, and is currently incurable. Advances in understanding the pathological mechanisms at a molecular level have been slow, with little attention focused on the early prodromal phase of the disease. Consequently, the development of early-acting disease-modifying therapies has been hindered. The olfactory bulb (OB), the brain region responsible for initial processing of olfactory information, is particularly affected early in PD at both functional and molecular levels but there is little information on how the cells in this region are affected by disease. Organotypic and primary OB cultures were developed and characterized. These platforms were then used to assess the effects of 3,4-dihydroxyphenylacetylaldehyde (DOPAL), a metabolite of dopamine present in increased levels in post-mortem PD tissue and which is thought to contribute to PD pathogenesis. Our findings showed that DOPAL exposure can recapitulate many aspects of PD pathology. Oxidative stress, depolarization of mitochondrial membranes, and neurodegeneration were all induced by DOPAL addition, as were measured transcriptomic changes consistent with those reported in PD clinical studies. These olfactory models of prodromal disease lend credence to the catecholaldehyde hypothesis of PD and provide insight into the mechanisms by which the OB may be involved in disease progression.
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Utility of the Cerebral Organoid Glioma 'GLICO' Model for Screening Applications.
Glioblastoma, a grade IV astrocytoma, is regarded as the most aggressive primary brain tumour with an overall median survival of 16.0 months following the standard treatment regimen of surgical resection, followed by radiotherapy and chemotherapy with temozolomide. Despite such intensive treatment, the tumour almost invariably recurs. This poor prognosis has most commonly been attributed to the initiation, propagation, and differentiation of cancer stem cells. Despite the unprecedented advances in biomedical research over the last decade, the current in vitro models are limited at preserving the inter- and intra-tumoural heterogeneity of primary tumours. The ability to understand and manipulate complex cancers such as glioblastoma requires disease models to be clinically and translationally relevant and encompass the cellular heterogeneity of such cancers. Therefore, brain cancer research models need to aim to recapitulate glioblastoma stem cell function, whilst remaining amenable for analysis. Fortunately, the recent development of 3D cultures has overcome some of these challenges, and cerebral organoids are emerging as cutting-edge tools in glioblastoma research. The opportunity to generate cerebral organoids via induced pluripotent stem cells, and to perform co-cultures with patient-derived cancer stem cells (GLICO model), has enabled the analysis of cancer development in a context that better mimics brain tissue architecture. In this article, we review the recent literature on the use of patient-derived glioblastoma organoid models and their applicability for drug screening, as well as provide a potential workflow for screening using the GLICO model. The proposed workflow is practical for use in most laboratories with accessible materials and equipment, a good first pass, and no animal work required. This workflow is also amenable for analysis, with separate measures of invasion, growth, and viability.
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Human organoids for Risk Group 4 virus research: a new frontier in investigating Nipah virus infection of the central nervous system.
UNLABELLED: New approach methodologies, such as high-complexity in vitro systems, are increasingly prioritized in biomedical research as potential alternatives to animal experimentation. We show that cerebral organoids derived from human induced pluripotent stem cells can be leveraged to (i) investigate isolate-specific replication dynamics of Nipah virus and (ii) model key histopathological lesions found in the brain tissue of infected human patients. Furthermore, we discuss the importance of organoid models for the study of Risk Group 4 viruses. IMPORTANCE: Advanced development of medical countermeasures against Risk Group 4 viruses, such as the Nipah virus, historically required testing in mammals under the FDA Animal Rule and translation of data to inform clinical trials in humans. Because the application of human organoids in research on viruses pathogenic for humans is conspecific, it bears the potential to reduce, refine, or replace animal studies where unnecessary. Human cerebral organoids are three-dimensional cell aggregates that resemble the developing human brain functionally and structurally. Brain organoids may be valuable in investigating the replication, neuroinvasion, pathogenesis, virulence, and persistence of neurotropic viruses and provide scientific discernment when developing medical countermeasures destined for the human end-user.
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Unveiling the potential: implications of successful somatic cell-to-ganglion organoid reprogramming.
Organoids have a wide range of potential applications in areas such as organ development, precision medicine, regenerative medicine, drug screening, disease modeling, and gene editing. Currently, most organoids are generated through three-dimensional (3D) in vitro culture of adult stem cells or pluripotent stem cells. However, this method of generating organoids still has several limitations and challenges, including complex manipulations, costly culturing materials, extended time requirements, and certain heterogeneity. Recently, we have found that fibroblasts, when overexpressing several key regulatory transcription factors, are able to directly and rapidly generate two types of ganglion organoids: sensory ganglion (SG) and autonomic ganglion (AG) organoids. They have structures and electrophysiological properties similar to those of endogenous organs in the body. Here, we provide a brief overview of organoid development, focusing on direct reprogramming of SG and AG organoids and their transplantation and regeneration. Finally, the advantages and prospects of direct reprogramming of organoids are discussed.