Purification and characterization of human neural stem and progenitor cells

CD200-based cell sorting results in homogeneous transplantable striatal neuroblasts for human cell therapy for Huntington's disease

Neurodegenerative diseases are characterized by selective loss of neurons. Cell replacement therapies are the most promising therapeutic strategies to restore the neuronal functions lost during these neurodegenerative processes. However, cell replacement-based clinical trials for Huntington's (HD) and Parkinson's diseases (PD) failed due to the large heterogeneity of the samples. Here, we identify CD200 as a cell surface marker for human striatal neuroblasts (NBs) using massively parallel single-cell RNA sequencing. Next, we set up a CD200-based immunomagnetic sorting pipeline that allows high-yield enrichment of human striatal NBs from in vitro differentiation of human pluripotent stem cells (hPSCs). We also show that sorted CD200-positive cells are striatal projection neuron (SPN)-committed NBs which survive upon intra-striatal transplantation in adult mice with no evidence of graft overgrowth in vivo. In conclusion, we implemented a new CD200 cell selection strategy that reduces the heterogeneity and batch-to-batch variation and potentially decreases the teratogenic risk of hPSC-based cell therapy for neurodegenerative diseases.

Structural and material basis of neuron-glioma interactions

The intricate interplay between neurons and gliomas has emerged as an important area of investigation in glioma biology. Accumulating evidence underscores that structural and material alterations constitute the fundamental basis of neuron‒glioma interactions and their pathological consequences. This review comprehensively examines the mechanisms underlying these interactions, with a particular emphasis on specialized structures that facilitate neuron‒glioma communication, including synapses, cell surface ion channels, and tumor microtubules (TMs). In addition to classical neurotransmitters, we highlight the exchange of cytokines, proteins, and extracellular vesicles (EVs) between these cell types. By synthesizing current research findings, this review establishes a conceptual framework for developing innovative therapeutic strategies targeting neuron‒glioma interfaces, offering new perspectives for glioma treatment approaches.

Protein Arginine Methyltransferases from Regulatory Function to Clinical Implication in Central Nervous System

Arginine methylation, catalyzed by protein arginine methyltransferases (PRMTs), is a regulatory key mechanism involved in various cellular processes such as gene expression, RNA processing, DNA damage repair. Increasing evidence highlights the crucial role of PRMTs in human diseases, including cancer, cardiovascular and metabolic diseases. Here, this review focuses on the latest findings regarding PRMTs in the central nervous system (CNS), emphasizing their regulatory roles in neural stem cells, neurons, and glial cells. Additionally, we examine the connection between PRMTs dysregulation and neurological diseases affecting the CNS, including brain tumors, neurodegenerative diseases, and neurodevelopmental disorders. Therefore, this review aims to deepen our understanding of PRMTs-mediated arginine methylation in CNS and open avenues for developing novel therapeutic strategies for neurological diseases.

The multilayered transcriptional architecture of glioblastoma ecosystems

In isocitrate dehydrogenase wildtype glioblastoma (GBM), cellular heterogeneity across and within tumors may drive therapeutic resistance. Here we analyzed 121 primary and recurrent GBM samples from 59 patients using single-nucleus RNA sequencing and bulk tumor DNA sequencing to characterize GBM transcriptional heterogeneity. First, GBMs can be classified by their broad cellular composition, encompassing malignant and nonmalignant cell types. Second, in each cell type we describe the diversity of cellular states and their pathway activation, particularly an expanded set of malignant cell states, including glial progenitor cell-like, neuronal-like and cilia-like. Third, the remaining variation between GBMs highlights three baseline gene expression programs. These three layers of heterogeneity are interrelated and partially associated with specific genetic aberrations, thereby defining three stereotypic GBM ecosystems. This work provides an unparalleled view of the multilayered transcriptional architecture of GBM. How this architecture evolves during disease progression is addressed in the companion manuscript by Spitzer et al.

Selenium promotes neural development through the regulation of GPX4 and SEPP1 in an iPSC-derived neuronal model

Selenium (Se) is incorporated into selenoproteins in the form of selenocysteine, which has biological functions associated with neural development. Unfortunately, the specific roles and mechanisms of selenoproteins at different stages of neuronal development are still unclear. Therefore, in this study, we successfully established a neuronal model derived from induced pluripotent stem cells (iPSC-iNeuron) and used Se nanoparticles (SeNPs@LNT) with high bioavailability to intervene at different stages of neural development in iPSC-iNeuron model. Interestingly, our results showed that SeNPs@LNT could not only accelerate the proliferation of neural progenitor cells (NPCs) by upregulating glutathione peroxidase 4 (GPX4) during the NPC stage, but also can promote neuronal differentiation by increasing selenoprotein P (SEPP1) during the neuronal stage, resulting in efficient and rapid neural development. In addition, further mechanistic studies showed that SeNPs@LNT can regulate selenoproteins by activating the PI3K/Akt/Nrf2 signaling pathway, thereby affecting neuronal development. Notably, Further analysis of ASD patients in National Center for Biotechnology Information single-cell RNA-seq datasets also revealed significantly lower GPX4 expression within NRGN-expressing neurons in ASD patients, and GO enrichment analysis of genes in NRGN-expressing neurons from ASD patients showed that the downregulation of selenoproteins due to aberrant selenoprotein synthesis may be closely associated with decreased ATP synthesis resulting from abnormal mitochondrial and respiratory chain signaling pathways. Taken together, this study provides evidence that SeNPs@LNT exerts a beneficial effect on early neural development through the regulation of selenoproteins.

Outer radial glia promotes white matter regeneration after neonatal brain injury

The developing gyrencephalic brain contains a large population of neural stem cells in the ventricular zone and outer subventricular zone (OSVZ), the latter populated by outer radial glia (oRG). The role of oRG during postnatal development is not well understood. We show that oRG cells increase proliferative capacity and contribute to oligodendrocyte precursor cell (OPC) production following brain injury in human infants and neonatal piglets, whose brains resemble the human brain in structure and development. RNA sequencing revealed oRG-specific transcriptional responses to injury in piglets and showed that the activating transcription factor 5 (ATF5) pathway positively regulates oRG proliferation. Intranasal activation of ATF5 using salubrinal enhanced OSVZ-derived oligodendrogenesis in the injured periventricular white matter and improved functional recovery. These results reveal a key role for postnatal oRG in brain injury recovery and identify ATF5 as a potential therapeutic target for treating white matter injury in infants.

Harnessing Intelligence from Brain Cells In Vitro

Harnessing intelligence from brain cells in vitro requires a multidisciplinary approach integrating wetware, hardware, and software. Wetware comprises the in vitro brain cells themselves, where differentiation from induced pluripotent stem cells offers ethical scalability; hardware typically involves a life support system and a setup to record the activity from and deliver stimulation to the brain cells; and software is required to control the hardware and process the signals coming from and going to the brain cells. This review provides a broad summary of the foundational technologies underpinning these components, along with outlining the importance of technology integration. Of particular importance is that this new technology offers the ability to extend beyond traditional methods that assess primarily the survival and spontaneous activity of neural cultures. Instead, the focus returns to the core function of neural tissue: the neurocomputational ability to process information and respond accordingly. Therefore, this review also covers work that, despite the relatively early state of current technology, has provided novel and meaningful understandings in the field of neuroscience along with opening exciting avenues for future research.

NOTCH, ERK, and SHH signaling respectively control the fate determination of cortical glia and olfactory bulb interneurons

During cortical development, radial glial cells (neural stem cells) initially are neurogenic, generating intermediate progenitor cells that exclusively produce glutamatergic pyramidal neurons. Next, radial glial cells generate tripotential intermediate progenitor cells (Tri-IPCs) that give rise to cortical astrocytes and oligodendrocytes, and olfactory bulb interneurons. The molecular mechanisms underlying the transition from cortical neurogenesis to gliogenesis, and the subsequent fate determination of cortical astrocytes, oligodendrocytes, and olfactory bulb interneurons, remain unclear. Here, we report that extracellular signal-regulated kinase (ERK) signaling plays a fundamental role in promoting cortical gliogenesis and the generation of Tri-IPCs. Additionally, sonic hedgehog-smoothened-glioma-associated oncogene homolog (SHH-SMO-GLI) activator signaling has an auxiliary function to ERK during these processes. We further demonstrate that, from Tri-IPCs, NOTCH signaling is crucial for the fate determination of astrocytes, while ERK signaling plays a prominent role in oligodendrocyte fate specification, and SHH signaling is required for the fate determination of olfactory bulb interneurons. We provide evidence suggesting that this mechanism is conserved in both mice and humans. Finally, we propose a unifying principle of mammalian cortical gliogenesis.

The Principle of Cortical Development and Evolution

Human's robust cognitive abilities, including creativity and language, are made possible, at least in large part, by evolutionary changes made to the cerebral cortex. This paper reviews the biology and evolution of mammalian cortical radial glial cells (primary neural stem cells) and introduces the concept that a genetically step wise process, based on a core molecular pathway already in use, is the evolutionary process that has molded cortical neurogenesis. The core mechanism, which has been identified in our recent studies, is the extracellular signal-regulated kinase (ERK)-bone morphogenic protein 7 (BMP7)-GLI3 repressor form (GLI3R)-sonic hedgehog (SHH) positive feedback loop. Additionally, I propose that the molecular basis for cortical evolutionary dwarfism, exemplified by the lissencephalic mouse which originated from a larger gyrencephalic ancestor, is an increase in SHH signaling in radial glia, that antagonizes ERK-BMP7 signaling. Finally, I propose that: (1) SHH signaling is not a key regulator of primate cortical expansion and folding; (2) human cortical radial glial cells do not generate neocortical interneurons; (3) human-specific genes may not be essential for most cortical expansion. I hope this review assists colleagues in the field, guiding research to address gaps in our understanding of cortical development and evolution.

Chiral Inorganic Nanomaterial-Based Diagnosis and Treatments for Neurodegenerative Diseases

Chiral nanomaterials are widely investigated over recent decades due to their biocompatibility and unique chiral effects. These key properties have significantly promoted the rapid development of chiral nanomaterials in bioengineering and medicine. In this review, the basic principles of constructing chiral nanomaterials along with the latest progress in research are comprehensively summarized. Then, the application of chiral nanomaterials for the diagnosis of neurodegenerative diseases (NDDs) is systematically described. In addition, the significant potential and broad prospects of chiral nanomaterials in the treatment of NDDs are highlighted from several aspects, including the disaggregation of neurofibrils, the scavenging of reactive oxygen species, regulation of the microbial-gut-brain axis, the elimination of senescent cells, and the promotion of directed differentiation in neural stem cells. Finally, a perspective of the challenges and future development of chiral nanomaterials for the treatment of NDDs is provided.

The meninges host a distinct compartment of regulatory T cells that preserves brain homeostasis

Our understanding of the meningeal immune system has recently burgeoned, particularly regarding how innate and adaptive effector cells are mobilized to meet brain challenges. However, information on how meningeal immunocytes guard brain homeostasis in healthy individuals remains limited. This study highlights the heterogeneous, polyfunctional regulatory T cell (Treg) compartment in the meninges. A Treg subtype specialized in controlling interferon-γ (IFN-γ) responses and another dedicated to regulating follicular B cell responses were substantial components of this compartment. Accordingly, punctual Treg ablation rapidly unleashed IFN-γ production by meningeal lymphocytes, unlocked access to the brain parenchyma, and altered meningeal B cell profiles. Distally, the hippocampus assumed a reactive state, with morphological and transcriptional changes in multiple glial cell types. Within the dentate gyrus, neural stem cells underwent more death and were blocked from further differentiation, which coincided with impairments in short-term spatial-reference memory. Thus, meningeal Tregs are a multifaceted safeguard of brain homeostasis at steady state.

Histone demethylase inhibitor KDM5-C70 regulates metabolomic and lipidomic programming during an astrocyte differentiation of rat neural stem cell

Lysine-specific histone demethylase (KDM) 5 inhibition by KDM5-C70 induces astrocytogenesis and highlights the importance of modulation of histone methylation in cell fate specification. This study investigated the role of the histone demethylase inhibitor KDM5-C70 in modulating the metabolic and lipidomic landscape during astrocyte differentiation of rat neural stem cells (NSCs). Using chemical derivatisation combined with gas chromatography-mass spectrometry, 42 metabolites were detected, indicating potential regulation of phospholipid metabolism. Subsequent lipidomic analysis, employing reverse-phase liquid chromatography with high-resolution quadrupole time-of-flight mass spectrometry, identified 180 lipid species and 9 lipid subclasses. Integrative analysis revealed that KDM5-C70 promoted astrocytogenesis through epigenetic changes linked to the attenuation of phosphatidylethanolamine (PE) biosynthesis pathways. The reduced expression of transcripts related to PE highlighted the significance of the PE pathway in influencing cell fate decisions. These quantitative metabolomic and lipidomic analyses not only advance our understanding of NSC differentiation but also lay the groundwork for potential therapeutic strategies targeting metabolic pathways in neurodegenerative diseases and neural injuries.

Erroneous Differentiation of Tendon Stem/Progenitor Cells in the Pathogenesis of Tendinopathy: Current Evidence and Future Perspectives

Tendinopathy is a condition characterized by persistent tendon pain, structural damage, and compromised functionality. Presently, the treatment for tendinopathy remains a formidable challenge, partly because of its unclear pathogenesis. Tendon stem/progenitor cells (TSPCs) are essential for tendon homeostasis, regeneration, remodeling, and repair. An innovative theory has been previously proposed, with insufficient evidence, that the erroneous differentiation of TSPCs may constitute one of the fundamental mechanisms underpinning tendinopathy. Over the past few years, there has been accumulating evidence for plausibility of this theory. In this review, we delve into alterations in the differentiation potential of TSPCs and the underlying mechanisms in the context of injury-induced tendinopathy, diabetic tendinopathy, and age-related tendinopathy to provide updated evidence on the erroneous differentiation theory. Despite certain limitations inherent in the existing body of evidence, the erroneous differentiation theory emerges as a promising and highly pertinent avenue for understanding tendinopathy. In the future, advanced methodologies will be harnessed to further deepen comprehension of this theory, paving the way for prospective developments in clinical therapies targeting TSPCs for the management of tendinopathy.

Mapping the developmental trajectory of human astrocytes reveals divergence in glioblastoma

Glioblastoma (GBM) is defined by heterogeneous and resilient cell populations that closely reflect neurodevelopmental cell types. Although it is clear that GBM echoes early and immature cell states, identifying the specific developmental programmes disrupted in these tumours has been hindered by a lack of high-resolution trajectories of glial and neuronal lineages. Here we delineate the course of human astrocyte maturation to uncover discrete developmental stages and attributes mirrored by GBM. We generated a transcriptomic and epigenomic map of human astrocyte maturation using cortical organoids maintained in culture for nearly 2 years. Through this approach, we chronicled a multiphase developmental process. Our time course of human astrocyte maturation includes a molecularly distinct intermediate period that serves as a lineage commitment checkpoint upstream of mature quiescence. This intermediate stage acts as a site of developmental deviation separating IDH-wild-type neoplastic astrocyte-lineage cells from quiescent astrocyte populations. Interestingly, IDH1-mutant tumour astrocyte-lineage cells are the exception to this developmental perturbation, where immature properties are suppressed as a result of D-2-hydroxyglutarate oncometabolite exposure. We propose that this defiance is a consequence of IDH1-mutant-associated epigenetic dysregulation, and we identified biased DNA hydroxymethylation (5hmC) in maturation genes as a possible mechanism. Together, this study illustrates a distinct cellular state aberration in GBM astrocyte-lineage cells and presents developmental targets for experimental and therapeutic exploration.

Psychopharmacological and Neuroregenerative Effects of a NF-κB Inhibitor under Conditions of Modeled Ethanol-Induced Encephalopathy

We studied the psychopharmacological effects of a NF-κB inhibitor, a stimulator of the functions of progenitor cells of the nervous tissue, under conditions of modeled ethanol-induced encephalopathy. The pharmacological agent improved indicators of the orientation and exploratory behavior and reproducibility of the conditioned passive avoidance reflex in experimental animals. These effects developed against the background of a significant increase in the content and proliferative activity of neural stem cells in the subventricular zone of the brain and intensification of their specialization. The results indicate the prospects of developing fundamentally new agents with regenerative activity based on NF-κB blockers for the treatment of alcoholic encephalopathy.

Characterizing progenitor cells in developing and injured spinal cord: Insights from single-nucleus transcriptomics and lineage tracing

Various mature tissue-resident cells exhibit progenitor characteristics following injury. However, the existence of endogenous stem cells with multiple lineage potentials in the adult spinal cord remains a compelling area of research. In this study, we present a cross-species investigation that extends from development to injury. We used single-nucleus transcriptomic sequencing and genetic lineage tracing to characterize neural cells in the spinal cord. Our findings show that ciliated ependymal cells lose neural progenitor gene signatures and proliferation ability following the differentiation of NPCs within the ventricular zone. By combining single-nucleus transcriptome datasets from the rhesus macaque spinal cord injury (SCI) model with developmental human spinal cord datasets, we revealed that ciliated ependymal cells respond minimally to injury and cannot revert to a developmental progenitor state. Intriguingly, we observed astrocytes transdifferentiating into mature oligodendrocytes postinjury through lineage tracing experiments. Further analysis identifies an intermediate-state glial cell population expressing both astrocyte and oligodendrocyte feature genes in adult spinal cords. The transition ratio from astrocytes into oligodendrocytes increased after remodeling injury microenvironment by functional scaffolds. Overall, our results highlight the remarkable multilineage potential of astrocytes in the adult spinal cord.

Enhanced neurogenesis after ischemic stroke: the interplay between endogenous and exogenous stem cells

ABSTRACT

Ischemic stroke is a significant global health crisis, frequently resulting in disability or death, with limited therapeutic interventions available. Although various intrinsic reparative processes are initiated within the ischemic brain, these mechanisms are often insufficient to restore neuronal functionality. This has led to intensive investigation into the use of exogenous stem cells as a potential therapeutic option. This comprehensive review outlines the ontogeny and mechanisms of activation of endogenous neural stem cells within the adult brain following ischemic events, with focus on the impact of stem cell-based therapies on neural stem cells. Exogenous stem cells have been shown to enhance the proliferation of endogenous neural stem cells via direct cell-to-cell contact and through the secretion of growth factors and exosomes. Additionally, implanted stem cells may recruit host stem cells from their niches to the infarct area by establishing so-called "biobridges." Furthermore, xenogeneic and allogeneic stem cells can modify the microenvironment of the infarcted brain tissue through immunomodulatory and angiogenic effects, thereby supporting endogenous neuroregeneration. Given the convergence of regulatory pathways between exogenous and endogenous stem cells and the necessity for a supportive microenvironment, we discuss three strategies to simultaneously enhance the therapeutic efficacy of both cell types. These approaches include: (1) co-administration of various growth factors and pharmacological agents alongside stem cell transplantation to reduce stem cell apoptosis; (2) synergistic administration of stem cells and their exosomes to amplify paracrine effects; and (3) integration of stem cells within hydrogels, which provide a protective scaffold for the implanted cells while facilitating the regeneration of neural tissue and the reconstitution of neural circuits. This comprehensive review highlights the interactions and shared regulatory mechanisms between endogenous neural stem cells and exogenously implanted stem cells and may offer new insights for improving the efficacy of stem cell-based therapies in the treatment of ischemic stroke.

Molecular and cellular dynamics of the developing human neocortex

The development of the human neocortex is highly dynamic, involving complex cellular trajectories controlled by gene regulation1. Here we collected paired single-nucleus chromatin accessibility and transcriptome data from 38 human neocortical samples encompassing both the prefrontal cortex and the primary visual cortex. These samples span five main developmental stages, ranging from the first trimester to adolescence. In parallel, we performed spatial transcriptomic analysis on a subset of the samples to illustrate spatial organization and intercellular communication. This atlas enables us to catalogue cell-type-specific, age-specific and area-specific gene regulatory networks underlying neural differentiation. Moreover, combining single-cell profiling, progenitor purification and lineage-tracing experiments, we have untangled the complex lineage relationships among progenitor subtypes during the neurogenesis-to-gliogenesis transition. We identified a tripotential intermediate progenitor subtype-tripotential intermediate progenitor cells (Tri-IPCs)-that is responsible for the local production of GABAergic neurons, oligodendrocyte precursor cells and astrocytes. Notably, most glioblastoma cells resemble Tri-IPCs at the transcriptomic level, suggesting that cancer cells hijack developmental processes to enhance growth and heterogeneity. Furthermore, by integrating our atlas data with large-scale genome-wide association study data, we created a disease-risk map highlighting enriched risk associated with autism spectrum disorder in second-trimester intratelencephalic neurons. Our study sheds light on the molecular and cellular dynamics of the developing human neocortex.

Transcriptomic and Functional Landscape of Adult Human Spinal Cord NSPCs Compared to iPSC-Derived Neural Progenitor Cells

The adult human spinal cord harbors diverse populations of neural stem/progenitor cells (NSPCs) essential for neuroregeneration and central nervous system repair. While induced pluripotent stem cell (iPSC)-derived NSPCs offer significant therapeutic potential, understanding their molecular and functional alignment with bona fide spinal cord NSPCs is crucial for developing autologous cell therapies that enhance spinal cord regeneration and minimize immune rejection. In this study, we present the first direct transcriptomic and functional comparison of syngeneic adult human NSPC populations, including bona fide spinal cord NSPCs and iPSC-derived NSPCs regionalized to the spinal cord (iPSC-SC) and forebrain (iPSC-Br). RNA sequencing analysis revealed distinct transcriptomic profiles and functional disparities among NSPC types. iPSC-Br NSPCs exhibited a close resemblance to bona fide spinal cord NSPCs, characterized by enriched expression of neurogenesis, axon guidance, synaptic signaling, and voltage-gated calcium channel activity pathways. Conversely, iPSC-SC NSPCs displayed significant heterogeneity, suboptimal regional specification, and elevated expression of neural crest and immune response-associated genes. Functional assays corroborated the transcriptomic findings, demonstrating superior neurogenic potential in iPSC-Br NSPCs. Additionally, we assessed donor-specific influences on NSPC behavior by analyzing gene expression and differentiation outcomes across syngeneic populations from multiple individuals. Donor-specific factors significantly modulated transcriptomic profiles, with notable variability in the alignment of iPSC-derived NSPCs to bona fide spinal cord NSPCs. Enrichment of pathways related to neurogenesis, axon guidance, and synaptic signaling varied across donors, highlighting the impact of genetic and epigenetic individuality on NSPC behavior.

Profiling cell identity and tissue architecture with single-cell and spatial transcriptomics

Single-cell transcriptomics has broadened our understanding of cellular diversity and gene expression dynamics in healthy and diseased tissues. Recently, spatial transcriptomics has emerged as a tool to contextualize single cells in multicellular neighbourhoods and to identify spatially recurrent phenotypes, or ecotypes. These technologies have generated vast datasets with targeted-transcriptome and whole-transcriptome profiles of hundreds to millions of cells. Such data have provided new insights into developmental hierarchies, cellular plasticity and diverse tissue microenvironments, and spurred a burst of innovation in computational methods for single-cell analysis. In this Review, we discuss recent advancements, ongoing challenges and prospects in identifying and characterizing cell states and multicellular neighbourhoods. We discuss recent progress in sample processing, data integration, identification of subtle cell states, trajectory modelling, deconvolution and spatial analysis. Furthermore, we discuss the increasing application of deep learning, including foundation models, in analysing single-cell and spatial transcriptomics data. Finally, we discuss recent applications of these tools in the fields of stem cell biology, immunology, and tumour biology, and the future of single-cell and spatial transcriptomics in biological research and its translation to the clinic.

Secretome of the Olfactory Ensheathing Cells Influences the Behavior of Neural Stem Cells

Olfactory ensheathing cell (OEC) transplantation demonstrates promising therapeutic results in neurological disorders, such as spinal cord injury. The emerging cell-free secretome therapy compensates for the limitations of cell transplantation, such as low cell survival rates. However, the therapeutic benefits of the human OEC secretome remain unclear. We harvested the secretome from human mucosal OECs and characterized its protein content, identifying 709 proteins in the human OEC secretome from three donors in two passages. Thirty-nine proteins, including neurological-related proteins, such as profilin-1, and antioxidants, such as peroxiredoxin-1 and glutathione S-transferase, were shared between the six samples. The secretome consistently demonstrated potential effects such as antioxidant activity, neuronal differentiation, and quiescence exit of neural stem cells (NSCs). The total secretome produced by OECs protects NSCs from H2O2-induced reactive oxygen species accumulation. During induction of neuronal differentiation, secretomes promoted neurite outgrowth, axon elongation, and expression of neuronal markers. The secretome ameliorated bone morphogenetic protein 4- and fibroblast growth factor 2-induced quiescence of NSCs. The human OEC secretome triggers NSCs to exit prime quiescence, which is related to increased phosphoribosomal protein S6 expression and RNA synthesis. The human OEC secretome has beneficial effects on NSCs and may be applied in neurological disease studies.

Human-Mouse Chimeric Brain Models to Study Human Glial-Neuronal and Macroglial-Microglial Interactions

Human-mouse chimeric brain models, generated by transplanting human induced pluripotent stem cell (hiPSC)-derived neural cells, are valuable for studying the development and function of human neural cells in vivo. Understanding glial-glial and glial-neuronal interactions is essential for unraveling the complexities of brain function and developing treatments for neurological disorders. To explore these interactions between human neural cells in vivo, we co-engrafted hiPSC-derived neural progenitor cells together with primitive macrophage progenitors into the neonatal mouse brain. This approach creates human-mouse chimeric brains containing human microglia, macroglia (astroglia and oligodendroglia), and neurons. Using super-resolution imaging and 3D reconstruction techniques, we examine the dynamics between human neurons and glia, and observe human microglia pruning synapses of human neurons, and often engulfing neurons themselves. Single-cell RNA sequencing analysis of the chimeric brain uncovers a close recapitulation of the human glial progenitor cell population, along with a dynamic stage in astroglial development that mirrors the processes found in the human brain. Furthermore, cell-cell communication analysis highlights significant neuronal-glial and macroglial-microglial interactions, especially the interaction between adhesion molecules neurexins and neuroligins between neurons and astroglia, emphasizing their key role in synaptogenesis. We also observed interactions between microglia and astroglia mediated by SPP1, crucial for promoting microglia growth and astrogliosis, and the PTN-MK pathways, instrumental in homeostatic maintenance and development in macroglial progenitors. This innovative co-transplantation model opens up new avenues for exploring the complex pathophysiological mechanisms underlying human neurological diseases. It holds particular promise for studying disorders where glial-neuronal interactions and non-cell-autonomous effects play crucial roles.

Co-culturing neural and bone mesenchymal stem cells in photosensitive hydrogel enhances spinal cord injury repair

In mammalian species, neural tissues cannot regenerate following severe spinal cord injury (SCI), for which stem cell transplantation is a promising treatment. Neural stem cells (NSCs) have the potential to repair SCI; however, in unfavourable microenvironments, transplanted NSCs mainly differentiate into astrocytes rather than neurons. In contrast, bone mesenchymal stem cells (BMSCs) promote the differentiation of NSCs into neurons and regulate inflammatory responses. Owing to their easily controllable mechanical properties and similarities to neural tissue, gelatin methacrylate (GelMA) hydrogels offer remarkable cell biocompatibility and regulate the differentiation of NSCs. Therefore, in this study, we propose co-culturing NSCs and BMSCs within low-modulus GelMA hydrogel scaffolds to promote regeneration following SCI. In vitro comparisons revealed that the viability, proliferation, migration, and neuron differentiation capacity of cells in these low-modulus scaffolds exhibit substantially superior performance compared to those in high-modulus hydrogel scaffolds. To the best of our knowledge, this study is the first to report that NSCs/BMSCs co-culture implants can remarkably enhance motor function recovery in SCI rats, reduce the area of spinal cord cavities, stimulate neuron regeneration, and suppress scar tissue formation. Thus, this hydrogel system loaded with co-cultured cells represents a promising therapeutic approach for SCI repair.

The potential of cellular homing behavior in tumor immunotherapy: from basic discoveries to clinical applications of immune, mesenchymal stem, and cancer cell homing

The efficacy of immunotherapy, a pivotal approach in the arsenal of cancer treatment strategies, is contingent on the capacity of effector cells to localize at the tumor site. The navigational capacity of these cells is intricately linked to the homing behaviors of specific cell types. Recent studies have focused on leveraging immune cells and mesenchymal stem cells (MSCs) homing for targeted tumor therapy and incorporating cancer cell homing properties into anti-tumor strategies. However, research and development of immunotherapy based on cancer cell homing remain in their preliminary stages. Enhancing the homing efficiency of effector cells is essential; therefore, understanding the underlying mechanisms and addressing immune resistance within the tumor microenvironment and challenges associated with in vivo therapeutic agent delivery are essential. This review firstly delineates the discovery and clinical translation of the three principal cell-homing behaviors. Secondly, we endeavor to conduct an in-depth analysis of existing research on the homing of immune and stem cells in cancer therapy, with the aim of identifying and understanding of the common applications, potential benefits, barriers, and critical success factors of cellular homing therapies. Finally, based on the understanding of the key factors of cellular homing therapies, we provide an overview and outlook on the enormous potential of harnessing cancer cells' self-homing to treat tumors. Although immunotherapy based on cell-homing behavior warrants further research, it remains a highly competitive treatment modality that can be combined with existing classic anti-cancer therapies. In general, combining the homing properties of cells to optimize their clinical effects is also one of the future research directions in the field of cell transplantation.

Artificial intelligence and omics in malignant gliomas

Glioblastoma multiforme (GBM) is one of the most common and aggressive type of malignant glioma with an average survival time of 12-18 mo. Despite the utilization of extensive surgical resections using cutting-edge neuroimaging, and advanced chemotherapy and radiotherapy, the prognosis remains unfavorable. The heterogeneity of GBM and the presence of the blood-brain barrier further complicate the therapeutic process. It is crucial to adopt a multifaceted approach in GBM research to understand its biology and advance toward effective treatments. In particular, omics research, which primarily includes genomics, transcriptomics, proteomics, and epigenomics, helps us understand how GBM develops, finds biomarkers, and discovers new therapeutic targets. The availability of large-scale multiomics data requires the development of computational models to infer valuable biological insights for the implementation of precision medicine. Artificial intelligence (AI) refers to a host of computational algorithms that is becoming a major tool capable of integrating large omics databases. Although the application of AI tools in GBM-omics is currently in its early stages, a thorough exploration of AI utilization to uncover different aspects of GBM (subtype classification, prognosis, and survival) would have a significant impact on both researchers and clinicians. Here, we aim to review and provide database resources of different AI-based techniques that have been used to study GBM pathogenesis using multiomics data over the past decade. We summarize different types of GBM-related omics resources that can be used to develop AI models. Furthermore, we explore various AI tools that have been developed using either individual or integrated multiomics data, highlighting their applications and limitations in the context of advancing GBM research and treatment.

Lung Immune Cell Niches and the Discovery of New Cell Subtypes

Immune cells in the lungs are important for maintaining lung function. The importance of immune cells in defending against lung diseases and infections is increasingly recognized. However, a primary knowledge gaps in current studies of lung immune cells is the understanding of their subtypes and functional heterogeneity. Increasing evidence supports the existence of novel immune cell subtypes that engage in the complex crosstalk between lung-resident immune cells, recruited immune cells, and epithelial cells. Therefore, further studies on how immune cells respond to perturbations in the pulmonary microenvironment are warranted. This review explores the processes behind the formation of the immune cell niche during lung development, and the characteristics and cell interaction modes of several major lung-resident immune cells. It indicates that distinct lung microenvironments or inflammatory niches can mediate the formation of different cell subtypes. These findings summarize and clarify paths to identify new cell subtypes that originate from resident progenitor cells and recruited peripheral cells, which are remodeled by the pulmonary microenvironment. The development of new techniques combining transcriptome analysis and location information is essential for identifying new immune cell subtypes and their relative immune niches, as well as for uncovering the molecular mechanisms of immune cell-mediated lung homeostasis.

Human iPSC-derived neural stem cells displaying radial glia signature exhibit long-term safety in mice

Human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NSCs) hold promise for treating neurodegenerative and demyelinating disorders. However, comprehensive studies on their identity and safety remain limited. In this study, we demonstrate that hiPSC-NSCs adopt a radial glia-associated signature, sharing key epigenetic and transcriptional characteristics with human fetal neural stem cells (hfNSCs) while exhibiting divergent profiles from glioblastoma stem cells. Long-term transplantation studies in mice showed robust and stable engraftment of hiPSC-NSCs, with predominant differentiation into glial cells and no evidence of tumor formation. Additionally, we identified the Sterol Regulatory Element Binding Transcription Factor 1 (SREBF1) as a regulator of astroglial differentiation in hiPSC-NSCs. These findings provide valuable transcriptional and epigenetic reference datasets to prospectively define the maturation stage of NSCs derived from different hiPSC sources and demonstrate the long-term safety of hiPSC-NSCs, reinforcing their potential as a viable alternative to hfNSCs for clinical applications.

Sequencing-based study of neural induction of human dental pulp stem cells

Techniques for triggering neural differentiation of embryonic and induced pluripotent stem cells into neural stem cells and neurons have been established. However, neural induction of mesenchymal stem cells, including dental pulp stem cells (DPSCs), has been assessed primarily based on neural-related gene regulation, and detailed studies into the characteristics and differentiation status of cells are lacking. Therefore, this study was aimed at evaluating the cellular components and differentiation pathways of neural lineage cells obtained via neural induction of human DPSCs. Human DPSCs were induced to neural cells in monolayer culture and examined for gene expression and mechanisms underlying differentiation using microarray-based ingenuity pathway analysis. In addition, the neural lineage cells were subjected to single-cell RNA sequencing (scRNA-seq) to classify cell populations based on gene expression profiles and to elucidate their differentiation pathways. Ingenuity pathway analysis revealed that genes exhibiting marked overexpression, post-neuronal induction, such as FABP7 and ZIC1, were associated with neurogenesis. Furthermore, in canonical pathway analysis, axon guidance signals demonstrated maximum activation. The scRNA-seq and cell type annotations revealed the presence of neural progenitor cells, astrocytes, neurons, and a small number of non-neural lineage cells. Moreover, trajectory and pseudotime analyses demonstrated that the neural progenitor cells initially engendered neurons, which subsequently differentiated into astrocytes. This result indicates that the aforementioned neural induction strategy generated neural stem/progenitor cells from DPSCs, which might differentiate and proliferate to constitute neural lineage cells. Therefore, neural induction of DPSCs may present an alternative approach to pluripotent stem cell-based therapeutic interventions for nervous system disorders.

Modeling Glioma Intratumoral Heterogeneity with Primary Human Neural Stem and Progenitor Cells

Glioblastoma multiforme (GBM) is a deadly form of glioma notable for its significant intratumoral heterogeneity, which is believed to drive therapy resistance. GBM has been observed to mimic a neural stem cell hierarchy reminiscent of normal brain development. However, it is still unclear how cell-of-origin shapes intratumoral heterogeneity. Here, we develop a model of glioma initiation using neural stem and progenitor cells (NSPCs) purified from fetal human brain tissue. We previously described a method to prospectively isolate and culture tripotent neural stem cells (NSCs), bipotent glial progenitor cells (GPCs), and unipotent oligodendrocyte precursor cells (OPCs). We transduced these isogenic lines with dominant-negative TP53R175H and NF1 knockdown, a commonly-used genetic model of GBM in mice. These reprogrammed lines robustly engrafted when transplanted into the brains of immunodeficient mice, and showed significant expansion over time. Engrafted cells were reextracted from the mouse brain for single cell RNA sequencing (scRNA-seq), in order to quantify how the cell-of-origin modulates the cellular subtypes found in the resulting tumor. This result revealed the strong influence the cell-of-origin plays in glioma heterogeneity. Our platform is highly adaptable and allows for modular and systematic interrogation of how cell-of-origin shape the tumor landscape.

Neural Influences on Tumor Progression Within the Central Nervous System

For decades, researchers have studied how brain tumors, the immune system, and drugs interact. With the advances in cancer neuroscience, which centers on defining and therapeutically targeting nervous system-cancer interactions, both within the local tumor microenvironment (TME) and on a systemic level, the subtle relationship between neurons and tumors in the central nervous system (CNS) has been deeply studied. Neurons, as the executors of brain functional activities, have been shown to significantly influence the emergence and development of brain tumors, including both primary and metastatic tumors. They engage with tumor cells via chemical or electrical synapses, directly regulating tumors or via intricate coupling networks, and also contribute to the TME through paracrine signaling, secreting proteins that exert regulatory effects. For instance, in a study involving a mouse model of glioblastoma, the authors observed a 42% increase in tumor volume when neuronal activity was stimulated, compared to controls (p < 0.01), indicating a direct correlation between neural activity and tumor growth. These thought-provoking results offer promising new strategies for brain tumor therapies, highlighting the potential of neuronal modulation to curb tumor progression. Future strategies may focus on developing drugs to inhibit or neutralize proteins and other bioactive substances secreted by neurons, break synaptic connections and interactions between infiltrating cells and tumor cells, as well as disrupt electrical coupling within glioma cell networks. By harnessing the insights gained from this research, we aspire to usher in a new era of brain tumor therapies that are both more potent and precise.

Evaluation of single-cell sorting accuracy using antibody-derived tag-based qPCR

Single-cell sorting (index sorting) is a widely used method to isolate one cell at a time using fluorescence-activated cell sorting (FACS) for downstream applications such as single-cell sequencing or single-cell expansion. Despite widespread use, few assays are available to evaluate the proteomic features of the sorted single cell and further confirm the accuracy of single-cell sorting. With this caveat, we developed a novel assay to confirm the protein expression of sorted single cells by co-staining cells with the same marker using both antibody-derived tags (ADTs) and fluorescent antibodies. After single-cell sorting, we amplified the oligo of the ADT reagent as a surrogate signal for the protein expression using multiplex TaqMan™ qPCR on sorted cells. This assay is not only useful for confirming the identity of a sorted single cell but also an efficient method to profile proteomic features at the single-cell level. Finally, we applied this assay to characterize protein expression on whole cell lysate. Because of the sensitivity of the TaqMan™ qPCR, we can detect protein expression from a small number of cells. In summary, the ADT-based qPCR assay developed here can be utilized to confirm single-cell sorting accuracy and characterizing protein expression on both single cells and whole cell lysate.

Neural Tissue-Like, not Supraphysiological, Electrical Conductivity Stimulates Neuronal Lineage Specification through Calcium Signaling and Epigenetic Modification

Electrical conductivity is a pivotal biophysical factor for neural interfaces, though optimal values remain controversial due to challenges isolating this cue. To address this issue, conductive substrates made of carbon nanotubes and graphene oxide nanoribbons, exhibiting a spectrum of conductivities from 0.02 to 3.2 S m-1, while controlling other surface properties is designed. The focus is to ascertain whether varying conductivity in isolation has any discernable impact on neural lineage specification. Remarkably, neural-tissue-like low conductivity (0.02-0.1 S m-1) prompted neural stem/progenitor cells to exhibit a greater propensity toward neuronal lineage specification (neurons and oligodendrocytes, not astrocytes) compared to high supraphysiological conductivity (3.2 S m-1). High conductivity instigated the apoptotic process, characterized by increased apoptotic fraction and decreased neurogenic morphological features, primarily due to calcium overload. Conversely, cells exposed to physiological conductivity displayed epigenetic changes, specifically increased chromatin openness with H3acetylation (H3ac) and neurogenic-transcription-factor activation, along with a more balanced intracellular calcium response. The pharmacological inhibition of H3ac further supported the idea that such epigenetic changes might play a key role in driving neuronal specification in response to neural-tissue-like, not supraphysiological, conductive cues. These findings underscore the necessity of optimal conductivity when designing neural interfaces and scaffolds to stimulate neuronal differentiation and facilitate the repair process.

Human amniotic epithelial stem cell-derived dopaminergic neuron-like cells ameliorate motor dysfunction in a rat model of Parkinson's disease

AIMS

Parkinson's disease (PD) remains a substantial clinical challenge due to the progressive loss of midbrain dopaminergic (DA) neurons in nigrostriatal pathway. In this study, human amniotic epithelial stem cells (hAESCs)-derived dopaminergic neuron-like cells (hAESCs-DNLCs) were generated, with the aim of providing new therapeutic approach to PD.

MATERIALS AND METHODS

hAESCs, which were isolated from discarded placentas, were induced to differentiate into hAESCs-DNLCs by following a "two stages" induction protocol. The differentiation efficiency was assessed by quantitative real-time PCR (qRT-PCR), immunocytochemistry (ICC), and ELISA. Immunogenicity, cell viability and tumorigenicity of hAESCs-DNLC were analyzed before in vivo experiments. Subsequently, hAESCs-DNLCs were transplanted into PD rats, behavioral tests were monitored after graft, and the regeneration of DA neurons was detected by immunohistochemistry (IHC). Furthermore, to trace hAESCs-DNLCs in vivo, cells were pre-labeled with PKH67 green fluorescence.

KEY FINDINGS

hAESCs were positive for pluripotent markers and highly expressed neural stem cells (NSCs) markers. Based on this, we established an induction method reliably generates hAESCs-DNLCs, which was evidenced by epithelium-to-neuron morphological changes, elevated expressions of neuronal and DA neuronal markers, and increased secretion of dopamine. Moreover, hAESCs-DNLCs maintained high cell viability, no tumorigenicity and low immunogenicity, suggesting hAESCs-DNLCs an attractive implant for PD therapy. Transplantation of hAESCs-DNLCs into PD rats significantly ameliorated motor disorders, as well as enhanced the reinnervation of TH+ DA neurons in nigrostriatal pathway.

SIGNIFICANCE

Our study has demonstrated evident therapeutic effects of hAESCs-DNLCs, and provides a safe and promising solution for PD.

Tracing the evolving dynamics and research hotspots of spinal cord injury and surgical decompression from 1975 to 2024: a bibliometric analysis

Background

Exploration of the benefits and timing of surgical decompression in spinal cord injury (SCI) has been a research hotspot. However, despite the higher volume and increasing emphasis on quality there remains no bibliometric view on SCI and surgical decompression. In this study, we aimed to perform bibliometric analysis to reveal the core countries, affiliations, journals, authors, and developmental trends in SCI and surgical decompression across the past 50 years.

Methods

Articles and reviews were retrieved from web of science core collection between 1975 and 2024. The bibliometrix package in R was used for data analysis and visualizing.

Results

A total of 8,688 documents were investigated, indicating an ascending trend in annual publications. The USA and China played as the leaders in scientific productivity. The University of Toronto led in institutional productions. Core authors, such as Michael G. Fehlings, showed high productivity, and occasional authors showed widespread interests. Core journals like Spine and Spinal Cord served as beacons in this field. The interaction of core authors and international collaboration accentuated the cross-disciplinary feature of the field. Prominent documents emphasized the clinical significance of early decompression in 24 h post SCI.

Conclusion

Based on comprehensive bibliometric analysis and literature review, we identified the hotspots and future directions of this field: (1) further investigation into the molecular and cellular mechanisms to provide pre-clinical evidence for biological effects of early surgical decompression in SCI animal models; (2) further evaluation and validation of the optimal time window of surgical decompression based on large cohort, considering the inherent heterogeneity of subpopulations in complicated immune responses post SCI; (3) further exploration on the benefits of early decompression on the neurological, functional, and clinical outcomes in acute SCI; (4) evaluation of the optimal surgical methods and related outcomes; (5) applications of artificial intelligence-based technologies in spinal surgical decompression.

Molecular and cellular dynamics of the developing human neocortex at single-cell resolution

The development of the human neocortex is a highly dynamic process and involves complex cellular trajectories controlled by cell-type-specific gene regulation1. Here, we collected paired single-nucleus chromatin accessibility and transcriptome data from 38 human neocortical samples encompassing both the prefrontal cortex and primary visual cortex. These samples span five main developmental stages, ranging from the first trimester to adolescence. In parallel, we performed spatial transcriptomic analysis on a subset of the samples to illustrate spatial organization and intercellular communication. This atlas enables us to catalog cell type-, age-, and area-specific gene regulatory networks underlying neural differentiation. Moreover, combining single-cell profiling, progenitor purification, and lineage-tracing experiments, we have untangled the complex lineage relationships among progenitor subtypes during the transition from neurogenesis to gliogenesis in the human neocortex. We identified a tripotential intermediate progenitor subtype, termed Tri-IPC, responsible for the local production of GABAergic neurons, oligodendrocyte precursor cells, and astrocytes. Remarkably, most glioblastoma cells resemble Tri-IPCs at the transcriptomic level, suggesting that cancer cells hijack developmental processes to enhance growth and heterogeneity. Furthermore, by integrating our atlas data with large-scale GWAS data, we created a disease-risk map highlighting enriched ASD risk in second-trimester intratelencephalic projection neurons. Our study sheds light on the gene regulatory landscape and cellular dynamics of the developing human neocortex.

Glioblastoma Neurovascular Progenitor Orchestrates Tumor Cell Type Diversity

Glioblastoma (GBM) is the deadliest form of primary brain tumor with limited treatment options. Recent studies have profiled GBM tumor heterogeneity, revealing numerous axes of variation that explain the molecular and spatial features of the tumor. Here, we seek to bridge descriptive characterization of GBM cell type heterogeneity with the functional role of individual populations within the tumor. Our lens leverages a gene program-centric meta-atlas of published transcriptomic studies to identify commonalities between diverse tumors and cell types in order to decipher the mechanisms that drive them. This approach led to the discovery of a tumor-derived stem cell population with mixed vascular and neural stem cell features, termed a neurovascular progenitor (NVP). Following in situ validation and molecular characterization of NVP cells in GBM patient samples, we characterized their function in vivo. Genetic depletion of NVP cells resulted in altered tumor cell composition, fewer cycling cells, and extended survival, underscoring their critical functional role. Clonal analysis of primary patient tumors in a human organoid tumor transplantation system demonstrated that the NVP has dual potency, generating both neuronal and vascular tumor cells. Although NVP cells comprise a small fraction of the tumor, these clonal analyses demonstrated that they strongly contribute to the total number of cycling cells in the tumor and generate a defined subset of the whole tumor. This study represents a paradigm by which cell type-specific interrogation of tumor populations can be used to study functional heterogeneity and therapeutically targetable vulnerabilities of GBM.

From neural tube to spinal cord: The dynamic journey of the dorsal neuroepithelium

In a developing embryo, formation of tissues and organs is remarkably precise in both time and space. Through cell-cell interactions, neighboring progenitors coordinate their activities, sequentially generating distinct types of cells. At present, we only have limited knowledge, rather than a systematic understanding, of the underlying logic and mechanisms responsible for cell fate transitions. The formation of the dorsal aspect of the spinal cord is an outstanding model to tackle these dynamics, as it first generates the peripheral nervous system and is later responsible for transmitting sensory information from the periphery to the brain and for coordinating local reflexes. This is reflected first by the ontogeny of neural crest cells, progenitors of the peripheral nervous system, followed by formation of the definitive roof plate of the central nervous system and specification of adjacent interneurons, then a transformation of roof plate into dorsal radial glia and ependyma lining the forming central canal. How do these peripheral and central neural branches segregate from common progenitors? How are dorsal radial glia established concomitant with transformation of the neural tube lumen into a central canal? How do the dorsal radial glia influence neighboring cells? This is only a partial list of questions whose clarification requires the implementation of experimental paradigms in which precise control of timing is crucial. Here, we outline some available answers and still open issues, while highlighting the contributions of avian models and their potential to address mechanisms of neural patterning and function.

Cellular and Molecular Insights into the Divergence of Neural Stem Cells on Matrigel and Poly-l-lysine Interfaces

Poly-l-lysine (PLL) and Matrigel, both classical coating materials for culture substrates in neural stem cell (NSC) research, present distinct interfaces whose effect on NSC behavior at cellular and molecular levels remains ambiguous. Our investigation reveals intriguing disparities: although both PLL and Matrigel interfaces are hydrophilic and feature amine functional groups, Matrigel stands out with lower stiffness and higher roughness. Based on this diversity, Matrigel surpasses PLL, driving NSC adhesion, migration, and proliferation. Intriguingly, PLL promotes NSC differentiation into astrocytes, whereas Matrigel favors neural differentiation and the physiological maturation of neurons. At the molecular level, Matrigel showcases a wider upregulation of genes linked to NSC behavior. Specifically, it enhances ECM-receptor interaction, activates the YAP transcription factor, and heightens glycerophospholipid metabolism, steering NSC proliferation and neural differentiation. Conversely, PLL upregulates genes associated with glial cell differentiation and amino acid metabolism and elevates various amino acid levels, potentially linked to its support for astrocyte differentiation. These distinct transcriptional and metabolic activities jointly shape the divergent NSC behavior on these substrates. This study significantly advances our understanding of substrate regulation on NSC behavior, offering novel insights into optimizing and targeting the application of these surface coating materials in NSC research.

Lineage specification in glioblastoma is regulated by METTL7B

Glioblastomas are the most common malignant brain tumors in adults; they are highly aggressive and heterogeneous and show a high degree of plasticity. Here, we show that methyltransferase-like 7B (METTL7B) is an essential regulator of lineage specification in glioblastoma, with an impact on both tumor size and invasiveness. Single-cell transcriptomic analysis of these tumors and of cerebral organoids derived from expanded potential stem cells overexpressing METTL7B reveal a regulatory role for the gene in the neural stem cell-to-astrocyte differentiation trajectory. Mechanistically, METTL7B downregulates the expression of key neuronal differentiation players, including SALL2, via post-translational modifications of histone marks.

The meninges host a unique compartment of regulatory T cells that bulwarks adult hippocampal neurogenesis

Our knowledge about the meningeal immune system has recently burgeoned, particularly our understanding of how innate and adaptive effector cells are mobilized to meet brain challenges. However, information on how meningeal immunocytes guard brain homeostasis in healthy individuals remains sparse. This study highlights the heterogeneous and polyfunctional regulatory-T (Treg) cell compartment in the meninges. A Treg subtype specialized in controlling Th1-cell responses and another known to control responses in B-cell follicles were substantial components of this compartment, foretelling that punctual Treg-cell ablation rapidly unleashed interferon-gamma production by meningeal lymphocytes, unlocked their access to the brain parenchyma, and altered meningeal B-cell profiles. Distally, the hippocampus assumed a reactive state, with morphological and transcriptional changes in multiple glial-cell types; within the dentate gyrus, neural stem cells showed exacerbated death and desisted from further differentiation, associated with inhibition of spatial-reference memory. Thus, meningeal Treg cells are a multifaceted bulwark to brain homeostasis at steady-state.

One sentence summary

A distinct population of regulatory T cells in the murine meninges safeguards homeostasis by keeping local interferon-γ-producing lymphocytes in check, thereby preventing their invasion of the parenchyma, activation of hippocampal glial cells, death of neural stem cells, and memory decay.

The Role of Smad3 in the Realization of the Growth Potential of Different Types of Neural Progenitor Cells and the Secretory Function of Neuroglia

The features of the participation of Smad3 in the functioning of neural stem cells (NSC), neuronal committed precursors (NCP), and neuroglial elements were studied in vitro. It was found that this intracellular signaling molecule enhances the clonogenic and proliferative activities of NCP and inhibits specialization of neuronal precursors. At the same time, Smad3 does not participate in the realization of the growth potential of NSC. With regard to the secretory function (production of neurotrophic growth factors) of neuroglial cells, the stimulating role of Smad3-mediated signaling was shown. These results indicate the promise of studying the possibility of using Smad3 as a fundamentally new target for neuroregenerative agents.

Transcription Factor EB Overexpression through Glial Fibrillary Acidic Protein Promoter Disrupts Neuronal Lamination by Dysregulating Neurogenesis during Embryonic Development

INTRODUCTION

Transcription factor EB (TFEB), a key regulator of autophagy and lysosomal biogenesis, has diverse roles in various physiological processes. Enhancing lysosomal function by TFEB activation has recently been implicated in restoring neural stem cell (NSC) function. Overexpression of TFEB can inhibit the cell cycle of newborn cortical NSCs. It has also been found that TFEB regulates the pluripotency transcriptional network in mouse embryonic stem cells independent of autophagy and lysosomal biogenesis. This study aims to explore the effects of TFEB activation on neurogenesis in vivo through transgenic mice.

METHODS

We developed a glial fibrillary acidic protein (GFAP)-driven TFEB overexpression mouse model (TFEB GoE) by crossing the floxed TFEB overexpression mice and hGFAP-Cre mice. We performed immunohistochemical and fluorescence staining on brain tissue from newborn mice to assess neurogenesis changes, employing markers such as GFAP, Nestin, Ki67, doublecortin (DCX), Tbr1, and NeuN to trace different stages of neural development and cell proliferation.

RESULTS

TFEB GoE mice exhibited premature mortality, dying 10-20 days after birth. Immunohistochemical analysis revealed significant abnormalities, including disrupted hippocampal structure and cortical layering. Compared to control mice, TFEB GoE mice showed a marked increase in radial glial cells (RGCs) in the hippocampus and cortex, with Ki67 staining indicating these cells were predominantly in a quiescent state. This suggests that TFEB overexpression suppresses RGC proliferation. Additionally, abnormal distributions of migrating neurons and mature neurons were observed, highlighted by DCX, Tbr1, and NeuN staining, indicating a disruption in normal neurogenesis.

CONCLUSION

This study, using transgenic animals in vivo, revealed that GFAP-driven TFEB overexpression leads to abnormal neural layering in the hippocampus and cortex by dysregulating neurogenesis. Our study is the first to discover the detrimental impact of TFEB overexpression on neurogenesis during embryonic development, which has important reference significance for future TFEB overexpression interventions in NSCs for treatment.

INTRODUCTION

Transcription factor EB (TFEB), a key regulator of autophagy and lysosomal biogenesis, has diverse roles in various physiological processes. Enhancing lysosomal function by TFEB activation has recently been implicated in restoring neural stem cell (NSC) function. Overexpression of TFEB can inhibit the cell cycle of newborn cortical NSCs. It has also been found that TFEB regulates the pluripotency transcriptional network in mouse embryonic stem cells independent of autophagy and lysosomal biogenesis. This study aims to explore the effects of TFEB activation on neurogenesis in vivo through transgenic mice.

METHODS

We developed a glial fibrillary acidic protein (GFAP)-driven TFEB overexpression mouse model (TFEB GoE) by crossing the floxed TFEB overexpression mice and hGFAP-Cre mice. We performed immunohistochemical and fluorescence staining on brain tissue from newborn mice to assess neurogenesis changes, employing markers such as GFAP, Nestin, Ki67, doublecortin (DCX), Tbr1, and NeuN to trace different stages of neural development and cell proliferation.

RESULTS

TFEB GoE mice exhibited premature mortality, dying 10-20 days after birth. Immunohistochemical analysis revealed significant abnormalities, including disrupted hippocampal structure and cortical layering. Compared to control mice, TFEB GoE mice showed a marked increase in radial glial cells (RGCs) in the hippocampus and cortex, with Ki67 staining indicating these cells were predominantly in a quiescent state. This suggests that TFEB overexpression suppresses RGC proliferation. Additionally, abnormal distributions of migrating neurons and mature neurons were observed, highlighted by DCX, Tbr1, and NeuN staining, indicating a disruption in normal neurogenesis.

CONCLUSION

This study, using transgenic animals in vivo, revealed that GFAP-driven TFEB overexpression leads to abnormal neural layering in the hippocampus and cortex by dysregulating neurogenesis. Our study is the first to discover the detrimental impact of TFEB overexpression on neurogenesis during embryonic development, which has important reference significance for future TFEB overexpression interventions in NSCs for treatment.

Global research trends and hotspots of artificial intelligence research in spinal cord neural injury and restoration-a bibliometrics and visualization analysis

Background

Artificial intelligence (AI) technology has made breakthroughs in spinal cord neural injury and restoration in recent years. It has a positive impact on clinical treatment. This study explores AI research's progress and hotspots in spinal cord neural injury and restoration. It also analyzes research shortcomings related to this area and proposes potential solutions.

Methods

We used CiteSpace 6.1.R6 and VOSviewer 1.6.19 to research WOS articles on AI research in spinal cord neural injury and restoration.

Results

A total of 1,502 articles were screened, in which the United States dominated; Kadone, Hideki (13 articles, University of Tsukuba, JAPAN) was the author with the highest number of publications; ARCH PHYS MED REHAB (IF = 4.3) was the most cited journal, and topics included molecular biology, immunology, neurology, sports, among other related areas.

Conclusion

We pinpointed three research hotspots for AI research in spinal cord neural injury and restoration: (1) intelligent robots and limb exoskeletons to assist rehabilitation training; (2) brain-computer interfaces; and (3) neuromodulation and noninvasive electrical stimulation. In addition, many new hotspots were discussed: (1) starting with image segmentation models based on convolutional neural networks; (2) the use of AI to fabricate polymeric biomaterials to provide the microenvironment required for neural stem cell-derived neural network tissues; (3) AI survival prediction tools, and transcription factor regulatory networks in the field of genetics were discussed. Although AI research in spinal cord neural injury and restoration has many benefits, the technology has several limitations (data and ethical issues). The data-gathering problem should be addressed in future research, which requires a significant sample of quality clinical data to build valid AI models. At the same time, research on genomics and other mechanisms in this field is fragile. In the future, machine learning techniques, such as AI survival prediction tools and transcription factor regulatory networks, can be utilized for studies related to the up-regulation of regeneration-related genes and the production of structural proteins for axonal growth.

Standardisation is the key to the sustained, rapid and healthy development of stem cell-based therapy

BACKGROUND

Stem cell-based therapy (SCT) is an important component of regenerative therapy that brings hope to many patients. After decades of development, SCT has made significant progress in the research of various diseases, and the market size has also expanded significantly. The transition of SCT from small-scale, customized experiments to routine clinical practice requires the assistance of standards. Many countries and international organizations around the world have developed corresponding SCT standards, which have effectively promoted the further development of the SCT industry.

METHODS

We conducted a comprehensive literature review to introduce the clinical application progress of SCT and focus on the development status of SCT standardization.

RESULTS

We first briefly introduced the types and characteristics of stem cells, and summarized the current clinical application and market development of SCT. Subsequently, we focused on the development status of SCT-related standards as of now from three levels: the International Organization for Standardization (ISO), important international organizations, and national organizations. Finally, we provided perspectives and conclusions on the significance and challenges of SCT standardization.

CONCLUSIONS

Standardization plays an important role in the sustained, rapid and healthy development of SCT.

Features of Intracellular Signal Transduction in Neural Stem Cells under the Influence of Alkaloid Songorine, an Agonist of Fibroblast Growth Factor Receptors

We performed a comparative in vitro study of the involvement of NF-κB, PI3K, cAMP, ERK1/2, p38, JAKs, STAT3, JNK, and p53-dependent intracellular signaling in the functioning of neural stem cells (NSC) under the influence of basic fibroblast growth factor (FGF) and FGF receptor agonist, diterpene alkaloid songorine. The significant differences in FGFR-mediated intracellular signaling in NSC were revealed for these ligands. In both cases, stimulation of progenitor cell proliferation occurs with the participation of NF-κB, PI3K, ERK1/2, JAKs, and STAT3, while JNK and p53, on the contrary, inhibit cell cycle progression. However, under the influence of songorin, cAMP- and p38-mediated cascades are additionally involved in the transmission of the NSC division-activating signal. In addition, unlike FGF, the alkaloid stimulates progenitor cell differentiation by activating ERK1/2, p38, JNK, p53, and STAT3.

Understanding immune microenvironment alterations in the brain to improve the diagnosis and treatment of diverse brain diseases

Abnormal inflammatory states in the brain are associated with a variety of brain diseases. The dynamic changes in the number and function of immune cells in cerebrospinal fluid (CSF) are advantageous for the early prediction and diagnosis of immune diseases affecting the brain. The aggregated factors and cells in inflamed CSF may represent candidate targets for therapy. The physiological barriers in the brain, such as the blood‒brain barrier (BBB), establish a stable environment for the distribution of resident immune cells. However, the underlying mechanism by which peripheral immune cells migrate into the brain and their role in maintaining immune homeostasis in CSF are still unclear. To advance our understanding of the causal link between brain diseases and immune cell status, we investigated the characteristics of immune cell changes in CSF and the molecular mechanisms involved in common brain diseases. Furthermore, we summarized the diagnostic and treatment methods for brain diseases in which immune cells and related cytokines in CSF are used as targets. Further investigations of the new immune cell subtypes and their contributions to the development of brain diseases are needed to improve diagnostic specificity and therapy.

BMP7 expression in mammalian cortical radial glial cells increases the length of the neurogenic period

The seat of human intelligence is the human cerebral cortex, which is responsible for our exceptional cognitive abilities. Identifying principles that lead to the development of the large-sized human cerebral cortex will shed light on what makes the human brain and species so special. The remarkable increase in the number of human cortical pyramidal neurons and the size of the human cerebral cortex is mainly because human cortical radial glial cells, primary neural stem cells in the cortex, generate cortical pyramidal neurons for more than 130 days, whereas the same process takes only about 7 days in mice. The molecular mechanisms underlying this difference are largely unknown. Here, we found that bone morphogenic protein 7 (BMP7) is expressed by increasing the number of cortical radial glial cells during mammalian evolution (mouse, ferret, monkey, and human). BMP7 expression in cortical radial glial cells promotes neurogenesis, inhibits gliogenesis, and thereby increases the length of the neurogenic period, whereas Sonic Hedgehog (SHH) signaling promotes cortical gliogenesis. We demonstrate that BMP7 signaling and SHH signaling mutually inhibit each other through regulation of GLI3 repressor formation. We propose that BMP7 drives the evolutionary expansion of the mammalian cortex by increasing the length of the neurogenic period.

Optogenetically modified human embryonic stem cell-derived otic neurons establish functional synaptic connection with cochlear nuclei

Spiral ganglia neurons (SGNs) impairment can cause deafness. One important therapeutic approach involves utilizing stem cells to restore impaired auditory circuitry. Nevertheless, the inadequate implementation of research methodologies poses a challenge in accurately assessing the functionality of derived cells within the circuit. Here, we describe a novel method for converting human embryonic stem cells (hESCs) into otic neurons (ONs) and assess their functional connectivity using an optogenetic approach with cells or an organotypic slice of rat cochlear nucleus (CN) in coculture. Embryonic stem cell-derived otic neurons (eONs) exhibited SGN marker expression and generated functional synaptic connection when cocultured with cochlear nucleus neurons (CNNs). Synapsin 1 and VGLUT expression are found in the cochlear nucleus of brain slices, where eONs projected processes during the coculture of eONs and CN brain slices. Action potential spikes and INa+/IK+ of CNNs increased in tandem with light stimulations to eONs. These findings provide further evidence that eONs may be a candidate source to treat SGN-deafness.

Prospective isolation of neural stem and progenitor cells from the developing human brain

Prospective isolation of defined cell types is critical for the functional study of stem cells, especially in primary human tissues. Here, we present a protocol for purifying 10 transcriptomically and functionally distinct neural stem and progenitor cell types from the developing human brain using fluorescence-activated cell sorting. We describe steps for tissue dissociation, staining, and cell sorting as well as downstream functional experiments for measuring clonogenicity, differentiation, and engraftment potential of purified populations. For complete details on the use and execution of this protocol, please refer to Liu et al. (2023).1.

Genetic knockout of NTRK2 by CRISPR/Cas9 decreases neurogenesis and favors glial progenitors during differentiation of neural progenitor stem cells

The tropomyosin receptor kinase B (TrkB) is encoded by the NTRK2 gene. It belongs to the family of transmembrane tyrosine kinases, which have key roles in the development and maintenance of the nervous system. Brain-derived neurotrophic factor (BDNF) and the neurotrophins NT3 and NT4/5 have high affinity for TrkB. Dysregulation of TrkB is associated to a large spectrum of diseases including neurodegeneration, psychiatric diseases and some cancers. The function of TrkB and its role in neural development have mainly been decrypted using transgenic mouse models, pharmacological modulators and human neuronal cell lines overexpressing NTRK2. In this study, we identified high expression and robust activity of TrkB in ReNcell VM, an immortalized human neural progenitor stem cell line and generated NTRK2-deficient (NTRK2-/-) ReNcell VM using the CRISPR/Cas9 gene editing technology. Global transcriptomic analysis revealed major changes in expression of specific genes responsible for neurogenesis, neuronal development and glial differentiation. In particular, key neurogenic transcription factors were massively down-regulated in NTRK2-/- cells, while early glial progenitor markers were enriched in NTRK2-/- cells compared to NTRK2+/+. This indicates a previously undescribed inhibitory role of TrkB on glial differentiation in addition to its well-described pro-neurogenesis role. Altogether, we have generated for the first time a human neural cell line with a loss-of-function mutation of NTRK2, which represents a reproducible and readily available cell culture system to study the role of TrkB during human neural differentiation, analyze the role of TrkB isoforms as well as validate TrkB antibodies and pharmacological agents targeting the TrkB pathway.