Your browser does not allow saving data (e.g. private mode): bookmarks will be lost when the tab closes.
Search PubMed
Keywords, author, journal, years — results from PubMed, abstracts with Russian translation, bookmarks in your browser.
Found: 5 450
Page 74 of 545-
Animus: human-embodied animals.
We review recent research to introduce human brain organoids into the brains of infant rats. This research shows these organoids integrate and function to affect behaviour in rats. We argue that this raises issues of moral status that will imminently arise and must be addressed through functional studies of these new life forms. We situate this research in the broader context of the biological revolution, arguing we already have the technological power to create fully human embodied animals. This raises profound, so far unaddressed ethical issues which call for urgent attention.
-
FGF2 Boost for Driving Forebrain Organoid Maturation Under Static Conditions.
Forebrain organoids (FOs) closely replicate key features of human brain, but often develop necrotic cores due to oxygen diffusion limits, resulting in disassembly. While dynamic culture devices can mitigate this, they add variability and diverge from adult cerebral static environment. Inspired by allometric scaling principles of brain growth, we developed a uniform, static culture protocol applying a 1-day transient high-dose Fibroblast Growth Factor 2 (100 ng/ml) treatment before neural induction. This acted as a proliferative stimulus, promoting long-term viability and structural integrity. Using human embryonic stem cells, early-FOs with diameters of 500-1000 µm achieved an 83.33% survival rate at 20 days in vitro (DIV). Area and volume increased significantly during 60 DIV culture period, but between 30 and 60 DIV they plateaued, indicating a transition from neural development to maturation. Weight increased until 30 DIV, but it significantly dropped between 30 and 60 DIV, possibly reflecting the formation of lumen-like structures. At 60 DIV, immunofluorescence revealed organized PAX6+ ventricle-like structures, where SOX2 marked neural progenitors, TUJ1 and MAP2 indicated mature neurons, GFAP identified astrocytes, and SYN1 highlighted emerging synaptic networks. This scalable protocol supports robust FOs generation, providing optimization and practical improvement within established frameworks to advance precision medicine.
-
Advancing preclinical models of psychiatric disorders with human brain organoid cultures.
Psychiatric disorders are often distinguished from neurological disorders in that the former do not have characteristic lesions or findings from cerebrospinal fluid, electroencephalograms (EEGs), or brain imaging, and furthermore do not have commonly recognized convergent mechanisms. Psychiatric disorders commonly involve clinical diagnosis of phenotypic behavioral disturbances of mood and psychosis, often with a poorly understood contribution of environmental factors. As such, psychiatric disease has been challenging to model preclinically for mechanistic understanding and pharmaceutical development. This review compares commonly used animal paradigms of preclinical testing with evolving techniques of induced pluripotent cell culture with a focus on emerging three-dimensional models. Advances in complexity of 3D cultures, recapitulating electrical activity in utero, and disease modeling of psychosis, mood, and environmentally induced disorders are reviewed. Insights from these rapidly expanding technologies are discussed as they pertain to the utility of human organoid and other models in finding novel research directions, validating pharmaceutical action, and recapitulating human disease.
-
Reliability of human cortical organoid generation.
The differentiation of pluripotent stem cells in three-dimensional cultures can recapitulate key aspects of brain development, but protocols are prone to variable results. Here we differentiated multiple human pluripotent stem cell lines for over 100 d using our previously developed approach to generate brain-region-specific organoids called cortical spheroids and, using several assays, found that spheroid generation was highly reliable and consistent. We anticipate the use of this approach for large-scale differentiation experiments and disease modeling.
-
Brain-Region-Specific Organoids Using Mini-bioreactors for Modeling ZIKV Exposure.
Cerebral organoids, three-dimensional cultures that model organogenesis, provide a new platform to investigate human brain development. High cost, variability, and tissue heterogeneity limit their broad applications. Here, we developed a miniaturized spinning bioreactor (SpinΩ) to generate forebrain-specific organoids from human iPSCs. These organoids recapitulate key features of human cortical development, including progenitor zone organization, neurogenesis, gene expression, and, notably, a distinct human-specific outer radial glia cell layer. We also developed protocols for midbrain and hypothalamic organoids. Finally, we employed the forebrain organoid platform to model Zika virus (ZIKV) exposure. Quantitative analyses revealed preferential, productive infection of neural progenitors with either African or Asian ZIKV strains. ZIKV infection leads to increased cell death and reduced proliferation, resulting in decreased neuronal cell-layer volume resembling microcephaly. Together, our brain-region-specific organoids and SpinΩ provide an accessible and versatile platform for modeling human brain development and disease and for compound testing, including potential ZIKV antiviral drugs.
-
Human amygdala-like telencephalic organoids model stress circuitry in assembloid systems.
Human emotional and stress responses are orchestrated by subcortical limbic circuits, with the amygdala playing a central role in integrating affective, sensory, and endocrine signals. Despite the urgent need to understand how these circuits develop and contribute to anxiety and stress-related disorders, progress has been hindered by lack of ex vivo human models. Here, we generated human amygdala-like telencephalic organoids (hATOs) that recapitulate cellular composition, region-specific development, and key features of the amygdala. By assembling hATOs with a hypothalamic organoid (hypoTO) with paraventricular nucleus (PVN)-like features, we modeled the amygdala-hypothalamus-like interaction, which enabled circuit-level analysis of stress-responsive signaling. Exposure to cortisol led to robust upregulation of BCYRN1, a primate-specific retrotransposon-derived noncoding RNA, which uncovered a previously unrecognized mechanism of stress hormone signaling to retrotransposon biology and human-specific synaptic regulation. These findings highlight the potential of hATOs to understand molecular features of affective circuitry underlying emotion and the stress response and neuropsychiatric disorders.
-
Modeling Neurodegenerative Microenvironment Using Cortical Organoids Derived from Human Stem Cells.
Alzheimer's disease (AD) is one of the most common neurodegenerative disorders and causes cognitive impairment and memory deficits of the patients. The mechanism of AD is not well known, due to lack of human brain models. Recently, mini-brain tissues called organoids have been derived from human induced pluripotent stem cells (hiPSCs) for modeling human brain development and neurological diseases. Thus, the objective of this research is to model and characterize neural degeneration microenvironment using three-dimensional (3D) forebrain cortical organoids derived from hiPSCs and study the response to the drug treatment. It is hypothesized that the 3D forebrain organoids derived from hiPSCs with AD-associated genetic background may partially recapitulate the extracellular microenvironment in neural degeneration. To test this hypothesis, AD-patient derived hiPSCs with presenilin-1 mutation were used for cortical organoid generation. AD-related inflammatory responses, matrix remodeling and the responses to DAPT, heparin (completes with heparan sulfate proteoglycans [HSPGs] to bind Aβ42), and heparinase (digests HSPGs) treatments were investigated. The results indicate that the cortical organoids derived from AD-associated hiPSCs exhibit a high level of Aβ42 comparing with healthy control. In addition, the AD-derived organoids result in an elevated gene expression of proinflammatory cytokines interleukin-6 and tumor necrosis factor-α, upregulate syndecan-3, and alter matrix remodeling protein expression. Our study demonstrates the capacity of hiPSC-derived organoids for modeling the changes of extracellular microenvironment and provides a potential approach for AD-related drug screening.
-
If Human Brain Organoids Are the Answer to Understanding Dementia, What Are the Questions?
Because our beliefs regarding our individuality, autonomy, and personhood are intimately bound up with our brains, there is a public fascination with cerebral organoids, the "mini-brain," the "brain in a dish". At the same time, the ethical issues around organoids are only now being explored. What are the prospects of using human cerebral organoids to better understand, treat, or prevent dementia? Will human organoids represent an improvement on the current, less-than-satisfactory, animal models? When considering these questions, two major issues arise. One is the general challenge associated with using any stem cell-generated preparation for in vitro modelling (challenges amplified when using organoids compared with simpler cell culture systems). The other relates to complexities associated with defining and understanding what we mean by the term "dementia." We discuss 10 puzzles, issues, and stumbling blocks to watch for in the quest to model "dementia in a dish."
-
Decoding the activated stem cell phenotype of the neonatally maturing pituitary.
The pituitary represents the endocrine master regulator. In mouse, the gland undergoes active maturation immediately after birth. Here, we in detail portrayed the stem cell compartment of neonatal pituitary. Single-cell RNA-sequencing pictured an active gland, revealing proliferative stem as well as hormonal (progenitor) cell populations. The stem cell pool displayed a hybrid epithelial/mesenchymal phenotype, characteristic of development-involved tissue stem cells. Organoid culturing recapitulated the stem cells' phenotype, interestingly also reproducing their paracrine activity. The pituitary stem cell-activating interleukin-6 advanced organoid growth, although the neonatal stem cell compartment was not visibly affected in Il6-/- mice, likely due to cytokine family redundancy. Further transcriptomic analysis exposed a pronounced WNT pathway in the neonatal gland, shown to be involved in stem cell activation and to overlap with the (fetal) human pituitary transcriptome. Following local damage, the neonatal gland efficiently regenerates, despite absence of additional stem cell proliferation, or upregulated IL-6 or WNT expression, all in line with the already high stem cell activation status, thereby exposing striking differences with adult pituitary. Together, our study decodes the stem cell compartment of neonatal pituitary, exposing an activated state in the maturing gland. Understanding stem cell activation is key to potential pituitary regenerative prospects.
-
Schizophrenia-associated NRXN1 deletions induce developmental-timing- and cell-type-specific vulnerabilities in human brain organoids.
De novo mutations and copy number deletions in NRXN1 (2p16.3) pose a significant risk for schizophrenia (SCZ). It is unclear how NRXN1 deletions impact cortical development in a cell type-specific manner and disease background modulates these phenotypes. Here, we leveraged human pluripotent stem cell-derived forebrain organoid models carrying NRXN1 heterozygous deletions in isogenic and SCZ patient genetic backgrounds and conducted single-cell transcriptomic analysis over the course of brain organoid development from 3 weeks to 3.5 months. Intriguingly, while both deletions similarly impacted molecular pathways associated with ubiquitin-proteasome system, alternative splicing, and synaptic signaling in maturing glutamatergic and GABAergic neurons, SCZ-NRXN1 deletions specifically perturbed developmental trajectories of early neural progenitors and accumulated disease-specific transcriptomic signatures. Using calcium imaging, we found that both deletions led to long-lasting changes in spontaneous and synchronous neuronal networks, implicating synaptic dysfunction. Our study reveals developmental-timing- and cell-type-dependent actions of NRXN1 deletions in unique genetic contexts.