Mitochondria metabolism sets the species-specific tempo of neuronal development

Hypoxia-ischemia and sexual dimorphism: modeling mitochondrial dysfunction using brain organoids

Hypoxic-ischemic encephalopathy (HIE) is a leading cause of neurodevelopmental morbidities in full-term infants. There is strong evidence of sexual differences in hypoxic-ischemic (HI) injury where male neonates are at higher risk as they are subject to more pronounced neurological deficits and death than females. The cellular and molecular mechanisms underlying these sexual discrepancies in HI injury are poorly understood. Mitochondrial dysregulation has been increasingly explored in brain diseases and represents a major target during HI events. In this review, we discuss (1) different mitochondrial functions in the central nervous system (2), mitochondrial dysregulation in the context of HI injury (3), sex-dependent mitochondrial pathways in HIE and (4) modeling of mitochondrial dysfunction using human brain organoids. Gaining insight into these novel aspects of mitochondrial function will offer valuable understanding of brain development and neurological disorders such as HI injury, paving the way for the discovery and creation of new treatment approaches.

Targeting mitochondria with natural polyphenols for treating Neurodegenerative Diseases: a comprehensive scoping review from oxidative stress perspective

Neurodegenerative diseases are a class of conditions with widespread detrimental impacts, currently lacking effective therapeutic drugs. Recent studies have identified mitochondrial dysfunction and the resultant oxidative stress as crucial contributors to the pathogenesis of neurodegenerative diseases. Polyphenols, naturally occurring compounds with inherent antioxidant properties, have demonstrated the potential to target mitochondria and mitigate oxidative stress. This therapeutic potential has garnered significant attention in recent years. Investigating the mitochondrial targeting capacity of polyphenols, their role in functional regulation, and their ability to modulate oxidative stress, along with exploring novel technologies and strategies for modifying polyphenol compounds and their formulations, holds promise for providing new avenues for the treatment of neurodegenerative diseases.

A primer on copper biology in the brain

This primer aims to expose scientists who study the brain to the field of copper biology. We briefly discuss key copper homeostasis mechanisms and proteins and place these functions in the context of the brain and neurodevelopment. A small number of key copper genes are explored as representative examples of the importance of this metal to the brain. We show that these genes are expressed throughout the brain and their defects are linked to a diverse array of neurological phenotypes, which we discuss further in the context of several neurological and neurodegenerative diseases associated with dysregulation of copper. This review aims to expose interested scientists to the fundamental roles for copper in the brain, the primary proteins responsible for maintaining copper homeostasis in the brain, and the classic neurological diseases associated with this metal.

How radial glia progenitor lineages generate cell-type diversity in the developing cerebral cortex

The cerebral cortex is arguably the most complex organ in humans. The cortical architecture is characterized by a remarkable diversity of neuronal and glial cell types that make up its neuronal circuits. Following a precise temporally ordered program, radial glia progenitor (RGP) cells generate all cortical excitatory projection neurons and glial cell-types. Cortical excitatory projection neurons are produced either directly or via intermediate progenitors, through indirect neurogenesis. How the extensive cortical cell-type diversity is generated during cortex development remains, however, a fundamental open question. How do RGPs quantitatively and qualitatively generate all the neocortical neurons? How does direct and indirect neurogenesis contribute to the establishment of neuronal and lineage heterogeneity? Whether RGPs represent a homogeneous and/or multipotent progenitor population, or if RGPs consist of heterogeneous groups is currently also not known. In this review, we will summarize the latest findings that contributed to a deeper insight into the above key questions.

Mitochondrial and peroxisomal fission in cortical neurogenesis

The human brain is unique in its cellular diversity, intricate cytoarchitecture, function, and complex metabolic and bioenergetic demands, for which mitochondria and peroxisomes are essential. Mitochondria are multifunctional organelles that coordinate various signaling pathways central to neurogenesis. The dynamic morphological changes of the mitochondrial network have been linked to the regulation of bioenergetic and metabolic states. Specific protein machinery is dedicated to mitochondrial fission and fusion, allowing organelle distribution during cell division, organelle repair, and adaptation to environmental stimuli (excellent reviews have been published on these topics [Kondadi and Reichert, 2024; Giacomello et al., 2020; Tilokani et al., 2018; Kraus et al., 2021; Navaratnarajah et al., 2021]). In parallel, peroxisomes contain over 50 different enzymes which regulate metabolic functions that are critical for neurogenesis (Berger et al., 2016; Hulshagen et al., 2008). Peroxisomes share many of the components of their fission machinery with the mitochondria and undergo fission to help meet metabolic demands in response to environmental stimuli (Schrader et al., 2016). This review focuses primarily on the machinery involved in mitochondrial and peroxisomal fission. Mitochondrial fission has been identified as a critical determinant of cell fate decisions (Iwata et al., 2023, 2020; Khacho et al., 2016; King et al., 2021; Prigione and Adjaye, 2010; Vantaggiato et al., 2019; Kraus et al., 2021). The connection between alterations in peroxisomal fission and metabolic changes associated with cellular differentiation remains less clear. Here, we provide an overview of the functional and regulatory aspects of the mitochondrial and peroxisomal fission machinery and provide insight into the current mechanistic understanding by which mitochondrial and peroxisomal fission influence neurogenesis.

The effect of mitochondrial-associated endoplasmic reticulum membranes (MAMs) modulation: New insights into therapeutic targets for depression

Depression is a prevalent mental disorder with high morbidity and mortality and its pathogenesis remains exactly unclarified. However, mitochondria and endoplasmic reticulum (ER) are two highly dynamic organelles that perform an indispensable role in the development of depression. Mitochondrial dysfunction and ER stress are recognized as vital pathological hallmarks in depression. The changes of intracellular activities such as mitochondrial dynamics, mitophagy, energy metabolism and ER stress are closely correlated with the progression of depression. Moreover, organelles interactions are conducive to homeostasis and cellular functions, and mitochondrial-associated endoplasmic reticulum membranes (MAMs) serve as signaling hubs of the two organelles and the coupling of the pathological progression. The main roles of MAMs are involved in metabolism, signal transduction, lipid transport, and maintenance of its structure and function. At present, accumulating studies elucidated that MAMs have gradually become a novel therapeutic target in treatment of depression. In the review, we focus on influence of mitochondria dysfunction and ER stress on depression. Furthermore, we discuss the underlying role of MAMs in depression and highlight natural products targeting MAMs as potential antidepressants to treat depression.

Regional differences in progenitor metabolism shape brain growth during development

Mammals have particularly large forebrains compared with other brain parts, yet the developmental mechanisms underlying this regional expansion remain poorly understood. Here, we provide a single-cell-resolution birthdate atlas of the mouse brain (www.neurobirth.org), which reveals that while hindbrain neurogenesis is transient and restricted to early development, forebrain neurogenesis is temporally sustained through reduced consumptive divisions of ventricular zone progenitors. This atlas additionally reveals region-specific patterns of direct and indirect neurogenesis. Using single-cell RNA sequencing, we identify evolutionarily conserved cell-cycle programs and metabolism-related molecular pathways that control regional temporal windows of proliferation. We identify the late neocortex-enriched mitochondrial protein FAM210B as a key regulator using in vivo gain- and loss-of-function experiments. FAM210B elongates mitochondria and increases lactate production, which promotes progenitor self-replicative divisions and, ultimately, the larger clonal size of their progeny. Together, these findings indicate that spatiotemporal heterogeneity in mitochondrial function regulates regional progenitor cycling behavior and associated clonal neuronal production during brain development.

Photobiomodulation therapy increases neural stem cell pool in aged 3xTg-AD mice

Presently approved Alzheimer's Disease (AD) therapeutics are designed for targeted removal of the AD-related toxic protein aggregate amyloid-β (Aβ) and have only shown moderate efficacy at slowing disease progression. Reversal of cognitive decline requires both removal of toxic aggregates and repair of the cellular systems damaged by decades of exposure to these aggregates. Adult hippocampal neurogenesis (AHN) is one such system that is known to be affected early and severely in the development of AD. Moreover, preserved AHN is associated with cognitive resilience to AD neuropathology. Therefore, targeted therapies to improve or enhance neurogenesis should be considered in addition to the removal of toxic protein aggregates. Photobiomodulation (PBM) using 670 nm LED light has been shown to induce synaptic resilience to and removal of AD-related toxic protein aggregates. In this study, we aimed to assess the effect of PBM on a mouse model of advanced AD neuropathology. Transgenic 3xTg-AD mice (15- to 17-month old) were randomized to receive PBM or SHAM therapy for one month, followed by neuropathological assessments. Our results show that one month of PBM therapy reduces hyperphosphorylated tau burden and partially rescues AHN in aged 3xTg-AD mice as compared to SHAM-treated transgenic mice. These data support the notion that PBM has the potential to be an effective non-invasive therapy to help preserve AHN and reduce cognitive dysfunction in moderate to advanced AD.

Chimeric brain models: Unlocking insights into human neural development, aging, diseases, and cell therapies

Human-rodent chimeric brain models serve as a unique platform for investigating the pathophysiology of human cells within a living brain environment. These models are established by transplanting human tissue- or human pluripotent stem cell (hPSC)-derived macroglial, microglial, or neuronal lineage cells, as well as cerebral organoids, into the brains of host animals. This approach has opened new avenues for exploring human brain development, disease mechanisms, and regenerative processes. Here, we highlight recent advancements in using chimeric models to study human neural development, aging, and disease. Additionally, we explore the potential applications of these models for studying human glial cell-replacement therapies, studying in vivo human glial-to-neuron reprogramming, and harnessing single-cell omics and advanced functional assays to uncover detailed insights into human neurobiology. Finally, we discuss strategies to enhance the precision and translational relevance of these models, expanding their impact in stem cell and neuroscience research.

Fate plasticity of interneuron specification

Neuronal subtype generation in the mammalian central nervous system is governed by competing genetic programs. The medial ganglionic eminence (MGE) produces two major cortical interneuron (IN) populations, somatostatin (Sst) and parvalbumin (Pvalb), which develop on different timelines. The extent to which external signals influence these identities remains unclear. Pvalb-positive INs are crucial for cortical circuit regulation but challenging to model in vitro. We grafted mouse MGE progenitors into diverse 2D and 3D co-culture systems, including mouse and human cortical, MGE, and thalamic models. Strikingly, only 3D human corticogenesis models promoted efficient, non-autonomous Pvalb differentiation, characterized by upregulation of Pvalb maturation markers, downregulation of Sst-specific markers, and the formation of perineuronal nets. Additionally, lineage-traced postmitotic Sst-positive INs upregulated Pvalb when grafted onto human cortical models. These findings reveal unexpected fate plasticity in MGE-derived INs, suggesting that their identities can be dynamically shaped by the environment.

Mitophagy in perioperative neurocognitive disorder: mechanisms and therapeutic strategies

Perioperative neurocognitive disorder (PND) is a common neurological complication after surgery/anesthesia in elderly patients that affect postoperative outcome and long-term quality of life, which increases the cost of family and social resources. The pathological mechanism of PND is complex and not fully understood, and the methods of prevention and treatment of PND are very limited, so it is particularly important to analyze the mechanism of PND. Research indicates that mitochondrial dysfunction is pivotal in the initiation and progression of PND, although the precise mechanisms remain elusive and could involve disrupted mitophagy. We reviewed recent studies on the link between mitophagy and PND, highlighting the role of key proteins in abnormal mitophagy and discussing therapeutic strategies aimed at mitophagy regulation. This provides insights into the mechanisms underlying PND and potential therapeutic targets.

Transcriptional conservation and evolutionary divergence of cell types across mammalian hypothalamus development

The hypothalamus, an "ancient" subcortical brain structure, maintains physiological homeostasis and controls native behaviors. The evolution of homeostatic regulation and behavioral control in mammals may rely on adaptable neuronal identity establishment but conserved neural patterning mechanisms during neurodevelopment. Here, we combined single-cell, single-nucleus, and spatial transcriptomic datasets to map the spatial patterning of diverse progenitor domains and reconstruct their neurogenic lineages in the developing human and mouse hypothalamus. While the regional organizers orchestrating neural patterning are conserved between primates and rodents, we identified a human-enriched neuronal subtype and found a substantial increase in neuromodulatory gene expression among human neurons. Furthermore, cross-species comparison demonstrated a potential redistribution of two neuroendocrine neuronal subtypes and a shift in inter-transmitter and transmitter-peptide coupling within hypothalamic dopamine neurons. Together, our study lays a critical foundation for understanding cellular development and evolution of the mammalian hypothalamus.

Targeting mitophagy in neurodegenerative diseases

Mitochondrial dysfunction is a hallmark of idiopathic neurodegenerative diseases, including Parkinson disease, amyotrophic lateral sclerosis, Alzheimer disease and Huntington disease. Familial forms of Parkinson disease and amyotrophic lateral sclerosis are often characterized by mutations in genes associated with mitophagy deficits. Therefore, enhancing the mitophagy pathway may represent a novel therapeutic approach to targeting an underlying pathogenic cause of neurodegenerative diseases, with the potential to deliver neuroprotection and disease modification, which is an important unmet need. Accumulating genetic, molecular and preclinical model-based evidence now supports targeting mitophagy in neurodegenerative diseases. Despite clinical development challenges, small-molecule-based approaches for selective mitophagy enhancement - namely, USP30 inhibitors and PINK1 activators - are entering phase I clinical trials for the first time.

Imeglimin, unlike metformin, does not perturb differentiation of human induced pluripotent stem cells towards pancreatic β-like cells and rather enhances gain in β cell identity gene sets

AIMS/INTRODUCTION

Metformin treatment for hyperglycemia in pregnancy (HIP) beneficially improves maternal glucose metabolism and reduces perinatal complications. However, metformin could impede pancreatic β cell development via impaired mitochondrial function. A new anti-diabetes drug imeglimin, developed based on metformin, improves mitochondrial function. Here we examine the effect of imeglimin on β cell differentiation using human induced pluripotent stem cell (iPSC)-derived pancreatic islet-like spheroid (SC-islet) models.

MATERIALS AND METHODS

Human iPSCs are differentiated into SC-islets by three-dimensional culture with and without imeglimin or metformin. Differentiation efficiencies of SC-islets were analyzed by flow cytometry, immunostaining, quantitative PCR, and insulin secretion assay. RNA sequencing and oxygen consumption rate were obtained for further characterization of SC-islets. SC-islets were cultured with proinflammatory cytokines, in part mimicking the uterus environment in HIP.

RESULTS

Metformin perturbed SC-islet differentiation while imeglimin did not alter it. Furthermore, imeglimin enhanced the gene expressions of β cell lineage markers. Maintenance of mitochondrial function and optimization of TGF-β and Wnt signaling were considered potential mechanisms for augmented β cell maturation by imeglimin. In the presence of proinflammatory cytokines, imeglimin ameliorated β cell differentiation impaired by cytokines and metformin.

CONCLUSIONS

Imeglimin does not perturb differentiation of SC-islet cells and rather enhances gain in β cell identity gene sets in contrast to metformin. This may lead to the improvement of in vitro β cell differentiation protocols.

A space for time. Exploring temporal regulation of plant development across spatial scales

Plants continuously undergo change during their life cycle, experiencing dramatic phase transitions altering plant form, and regulating the assignment and progression of cell fates. The relative timing of developmental events is tightly controlled and involves integration of environmental, spatial, and relative age-related signals and actors. While plant phase transitions have been studied extensively and many of their regulators have been described, less is known about temporal regulation on a smaller, cell-level scale. Here, using examples from both plant and animal systems, we outline time-dependent changes. Looking at systemic scale changes, we discuss the timing of germination, juvenile-to-adult transition, flowering, and senescence, together with regeneration timing. Switching to temporal regulation on a cellular level, we discuss several instances from the animal field in which temporal control has been examined extensively at this scale. Then, we switch back to plants and summarize examples where plant cell-level changes are temporally regulated. As time cannot easily be separated from signaling derived from the environment and tissue context, we next discuss factors that have been implicated in controlling the timing of developmental events, reviewing temperature, photoperiod, nutrient availability, as well as tissue context and mechanical cues on the cellular scale. Afterwards, we provide an overview of mechanisms that have been shown or implicated in the temporal control of development, considering metabolism, division control, mobile signals, epigenetic regulation, and the action of transcription factors. Lastly, we look at remaining questions for the future study of developmental timing in plants and how recent technical advancement can enable these efforts.

FOS binding sites are a hub for the evolution of activity-dependent gene regulatory programs in human neurons

After birth, sensory inputs to neurons trigger the induction of activity-dependent genes (ADGs) that mediate many aspects of neuronal maturation and plasticity. To identify human-specific ADGs, we characterized these genes in human-chimpanzee tetraploid neurons. We identified 235 ADGs that are differentially expressed between human and chimpanzee neurons and found that their nearby regulatory sites are species-biased in their binding of the transcription factor FOS. An assessment of these sites revealed that many are enriched for single nucleotide variants that promote or eliminate FOS binding in human neurons. Disrupting the function of individual species-biased FOS-bound enhancers diminishes expression of nearby genes and affects the firing dynamics of human neurons. Our findings indicate that FOS-bound enhancers are frequent sites of evolution and that they regulate human-specific ADGs that may contribute to the unusually protracted and complex process of postnatal human brain development.

WWC1 mutation drives dopamine dysregulation and synaptic imbalance in Tourette's syndrome

Tourette's syndrome (TS) is a major neurodevelopmental disorder characterized by childhood-onset motor and vocal tics. A W88C mutation in WWC1 gene is a notable risk factor for TS, but the underlying molecular mechanisms remain unclear due to the lack of suitable animal models. Here, we generate a mutant mouse line with human W88C mutation (W88CMut mice), which exhibits behavioral deficits similar to those observed in patients with TS, including repetitive motor behaviors and sensorimotor gating abnormalities. The W88C mutation leads to the degradation of kidney and brain (KIBRA) protein via a proteasomal pathway, evokes dopamine release in the dorsal striatum, and disrupts synaptic function through the dysregulation of Hippo pathway. Neuron-specific overexpression of wild-type WWC1 rescues synaptic and behavioral phenotypes in W88CMut mice. Together, this study not only provides a valuable mouse model for studying TS but also offers fresh insights into the molecular and synaptic mechanisms underlying neurodevelopmental abnormalities in TS.

Metabolic Atlas of Early Human Cortex Identifies Regulators of Cell Fate Transitions

Characterization of cell type emergence during human cortical development, which enables unique human cognition, has focused primarily on anatomical and transcriptional characterizations. Metabolic processes in the human brain that allow for rapid expansion, but contribute to vulnerability to neurodevelopmental disorders, remain largely unexplored. We performed a variety of metabolic assays in primary tissue and stem cell derived cortical organoids and observed dynamic changes in core metabolic functions, including an unexpected increase in glycolysis during late neurogenesis. By depleting glucose levels in cortical organoids, we increased outer radial glia, astrocytes, and inhibitory neurons. We found the pentose phosphate pathway (PPP) was impacted in these experiments and leveraged pharmacological and genetic manipulations to recapitulate these radial glia cell fate changes. These data identify a new role for the PPP in modulating radial glia cell fate specification and generate a resource for future exploration of additional metabolic pathways in human cortical development.

Single-Cell Analysis of Sex and Gender Differences in the Human Brain During Development and Disease

Sex and gender (SG) differences in the human brain are of interest to society and science as numerous processes are impacted by them, including brain development, behavior, and diseases. By collecting publicly available single-cell data from the in-utero to elderly age in healthy, Alzheimer's disease and multiple sclerosis samples, we identified and characterized SG-biased genes in ten brain cell types across 9 age and disease groups. Sex and gender differences in the transcriptome were present throughout the lifespan and across all cell types. Although there was limited overlap among SG-biased genes across different age and disease groups, we observed significant functional overlap. Female-biased genes are consistently enriched for brain-related processes, while male-biased genes are enriched for metabolic pathways. Additionally, mitochondrial genes showed a consistent female bias across cell types. We also found that androgen response elements (not estrogen) were significantly enriched in both male- and female-biased genes, and thymosin hormone targets being consistently enriched only in male-biased genes. We systematically characterised SG differences in brain development and brain-related disorders at a single-cell level, by analysing a total of publicly available 419,885 single nuclei from 161 human brain samples (72 females, 89 males). The significant enrichment of androgen (not estrogen) response elements in both male- and female-biased genes suggests that androgens are important regulators likely establishing these SG differences. Finally, we provide full characterization of SG-biased genes at different thresholds for the scientific community as a web resource.

Cell Type-Agnostic Transcriptomic Signatures Enable Uniform Comparisons of Neurodevelopment

Single-cell transcriptomics has revolutionized our understanding of neurodevelopmental cell identities, yet, predicting a cell type's developmental state from its transcriptome remains a challenge. We perform a meta-analysis of developing human brain datasets comprising over 2.8 million cells, identifying both tissue-level and cell-autonomous predictors of developmental age. While tissue composition predicts age within individual studies, it fails to generalize, whereas specific cell type proportions reliably track developmental time across datasets. Training regularized regression models to infer cell-autonomous maturation, we find that a cell type-agnostic model achieves the highest accuracy (error = 2.6 weeks), robustly capturing developmental dynamics across diverse cell types and datasets. This model generalizes to human neural organoids, accurately predicting normal developmental trajectories (R = 0.91) and disease-induced shifts in vitro. Furthermore, it extends to the developing mouse brain, revealing an accelerated developmental tempo relative to humans. Our work provides a unified framework for comparing neurodevelopment across contexts, model systems, and species.

Early central nervous system development and neuron regeneration

The nervous system is the most complex system in the human body, and the normal development of the central nervous system (CNS) is essential for maintaining the healthy life activities of the individual. CNS development requires the orchestration of multiple internal or external or direct or indirect factors to regulate neural stem cell fate specification. Here, we provide a broad overview of the regulatory system of nerve cell fate decisions and discuss the latest technological approaches to achieve neural regeneration. Understanding the CNS development and regeneration mechanisms has shifted the paradigm from traditional experiments to high-throughput sequencing.

Tile by tile: capturing the evolutionary mosaic of human conditions

The collection of Homo sapiens anatomical hallmarks hypothesized to support the 'human condition' did not appear at one specific time and place, but gradually, creating a reticulate evolutionary trajectory. The recent reconstruction of migration patterns and gene flows across different hominin species and populations draws a mosaic that we contend can be illuminated by genomic comparisons and specific experiments. Here, we first review key discoveries that could allow this experimental endeavor by describing recent advances in a variety of fields, stressing the importance of charting the current human neurodiversity as an interpretive substrate for evolutionary changes. Then, we identify key cellular and molecular observables. Finally, given the vast amount of possible variants, we focus the discussion on technologies that could allow their interrogation in a way that is compatible with the staggering amount of contemporary genomic and phenotypic characterization.

Unleashing metabolic power for axonal regeneration

Axon regeneration requires the mobilization of intracellular resources, including proteins, lipids, and nucleotides. After injury, neurons need to adapt their metabolism to meet the biosynthetic demands needed to achieve axonal regeneration. However, the exact contribution of cellular metabolism to this process remains elusive. Insights into the metabolic characteristics of proliferative cells may illuminate similar mechanisms operating in axon regeneration; therefore, unraveling previously unappreciated roles of metabolic adaptation is critical to achieving neuron regrowth, which is connected to the therapeutic strategies for neurological conditions necessitating nerve repairs, such as spinal cord injury and stroke. Here, we outline the metabolic role in axon regeneration and discuss factors enhancing nerve regrowth, highlighting potential novel metabolic treatments for restoring nerve function.

Metabolic activities are selective modulators for individual segmentation clock processes

Numerous cellular and molecular processes during embryonic development prompt the fundamental question of how their tempos are coordinated and whether a common global modulator exists. While the segmentation clock tempo scales with the kinetics of gene expression and degradation processes of the core clock gene Hes7 across mammals, the coordination of these processes remains unclear. This study examines whether metabolic activities serve as a global modulator for the segmentation clock, finding them to be selective instead. Several metabolic inhibitions extend the clock period but affect key processes differently: glycolysis inhibition slows Hes7 protein degradation and production delay without altering intron delay, while electron transport chain inhibition extends intron delay without influencing the other processes. Combinations of distinct metabolic inhibitions exhibit synergistic effects. We propose that the scaled kinetics of segmentation clock processes across species may result from combined selective modulators shaped by evolutionary constraints, rather than a single global modulator.

Using cortical organoids to understand the pathogenesis of malformations of cortical development

Malformations of cortical development encompass a broad range of disorders associated with abnormalities in corticogenesis. Widespread abnormalities in neuronal formation or migration can lead to small head size or microcephaly with disorganized placement of cell types. Specific, localized malformations are termed focal cortical dysplasias (FCD). Neurodevelopmental disorders are common in all types of malformations of cortical development with the most prominent being refractory epilepsy, behavioral disorders such as autism spectrum disorder (ASD), and learning disorders. Several genetic pathways have been associated with these disorders from control of cell cycle and cytoskeletal dynamics in global malformations to variants in growth factor signaling pathways, especially those interacting with the mechanistic target of rapamycin (mTOR), in FCDs. Despite advances in understanding these disorders, the underlying developmental pathways that lead to lesion formation and mechanisms through which defects in cortical development cause specific neurological symptoms often remains unclear. One limitation is the difficulty in modeling these disorders, as animal models frequently do not faithfully mirror the human phenotype. To circumvent this obstacle, many investigators have turned to three-dimensional human stem cell models of the brain, known as organoids, because they recapitulate early neurodevelopmental processes. High throughput analysis of these organoids presents a promising opportunity to model pathophysiological processes across the breadth of malformations of cortical development. In this review, we highlight advances in understanding the pathophysiology of brain malformations using organoid models.

MetaboLINK is a novel algorithm for unveiling cell-specific metabolic pathways in longitudinal datasets

Introduction

In the rapidly advancing field of 'omics research, there is an increasing demand for sophisticated bioinformatic tools to enable efficient and consistent data analysis. As biological datasets, particularly metabolomics, become larger and more complex, innovative strategies are essential for deciphering the intricate molecular and cellular networks.

Methods

We introduce a pioneering analytical approach that combines Principal Component Analysis (PCA) with Graphical Lasso (GLASSO). This method is designed to reduce the dimensionality of large datasets while preserving significant variance. For the first time, we applied the PCA-GLASSO algorithm (i.e., MetaboLINK) to metabolomics data derived from Nuclear Magnetic Resonance (NMR) spectroscopy performed on neural cells at various developmental stages, from human embryonic stem cells to neurons.

Results

The MetaboLINK analysis of longitudinal metabolomics data has revealed distinct pathways related to amino acids, lipids, and energy metabolism, uniquely associated with specific cell progenies. These findings suggest that different metabolic pathways play a critical role at different stages of cellular development, each contributing to diverse cellular functions.

Discussion

Our study demonstrates the efficacy of the MetaboLINK approach in analyzing NMR-based longitudinal metabolomic datasets, highlighting key metabolic shifts during cellular transitions. We share the methodology and the code to advance general 'omics research, providing a powerful tool for dissecting large datasets in neurobiology and other fields.

scMMO-atlas: a single cell multimodal omics atlas and portal for exploring fine cell heterogeneity and cell dynamics

Single-cell multimodal sequencing parallelly captures multiple modalities of the same cell, providing unparalleled insights into cell heterogeneity and cell dynamics. For example, joint profiling of chromatin accessibility and transcriptome from the same single cell (scATAC + RNA) identified new cell subsets within the well-defined clusters. However, lack of single-cell multimodal omics (scMMO) database has led to data fragmentation, seriously hindering access, utilization and mining of scMMO data. Here, we constructed a scMMO atlas by collecting and integrating various scMMO data, then constructed scMMO database and portal called scMMO-atlas (https://www.biosino.org/scMMO-atlas/). scMMO-atlas includes scATAC + RNA (ISSAAS-seq, SNARE-seq, paired-seq, sci-CAR, scCARE-seq, 10X Multiome and so on), scRNA + protein, scATAC + protein and scTri-modal omics data, with 3 168 824 cells from 27 cell tissues/organs. scMMO-atlas offered an interactive portal for visualization and featured analysis for each modality and the integrated data. Integrated analysis of scATAC + RNA data of mouse cerebral cortex in scMMO-atlas identified more cell subsets compared with unimodal omics data. Among these new cell subsets, there is an early astrocyte subset highly expressed Grm3, called Astro-Grm3. Furthermore, we identified Ex-L6-Tle4-Nrf1, a progenitor of Ex-L6-Tle4, indicating the statistical power provided by the big data in scMMO-atlas. In summary, scMMO-atlas offers cell atlas, database and portal to facilitate data utilization and biological insight.

Human iPSC-Derived MSCs Induce Neurotrophic Effects and Improve Metabolic Activity in Acute Neuronal Injury Models

Mesenchymal stromal cell (MSC) therapy has regenerative potentials to treat various pathological conditions including neurological diseases. MSCs isolated from various organs can differentiate into specific cell types to repair organ damages. However, their paracrine mechanisms are predicted to predominantly mediate their immunomodulatory, proangiogenic, and regenerative properties. While preclinical studies highlight the significant potential of MSC therapy in mitigating neurological damage from stroke and traumatic brain injury, the variability in clinical trial outcomes may stem from the inherent heterogeneity of somatic MSCs. Accumulating evidence has demonstrated that induced pluripotent stem cells (iPSCs) are an ideal alternative resource for the unlimited expansion and biomanufacturing of MSCs. Thus, we investigated how iPSC-derived MSCs (iMSCs) influence properties of iPSC-derived neurons. Our findings demonstrate that the secretome from iMSCs possesses neurotrophic effects, improving neuronal survival and promoting neuronal outgrowth and synaptic activity in vitro. Additionally, the iMSCs enhance metabolic activity via mitochondrial respiration in neurons, both in vitro and in mouse models. Glycolytic pathways also increased following the administration of iMSC secretome to iPSC-derived neurons. Consistently, in vivo experiments showed that intravenous administration of iMSCs compensated for the elevated energetic demand in male mice with irradiation-induced brain injury by restoring synaptic metabolic activity during acute brain damage. 18F-FDG PET imaging also detected an increase in brain glucose uptake following iMSC administration. Together, our results highlight the potential of iMSC-based therapy in treating neuronal damage in various neurological disorders, while paving the way for future research and potential clinical applications of iMSCs in regenerative medicine.

The multifaceted modulation of mitochondrial metabolism in tumorigenesis

Changes in mitochondrial metabolism produce a malignant transformation from normal cells to tumor cells. Mitochondrial metabolism, comprising bioenergetic metabolism, biosynthetic process, biomolecular decomposition, and metabolic signal conversion, obviously forms a unique sign in the process of tumorigenesis. Several oncometabolites produced by mitochondrial metabolism maintain tumor phenotype, which are recognized as tumor indicators. The mitochondrial metabolism synchronizes the metabolic and genetic outcome to the potent tumor microenvironmental signals, thereby further promoting tumor initiation. Moreover, the bioenergetic and biosynthetic metabolism within tumor mitochondria orchestrates dynamic contributions toward cancer progression and invasion. In this review, we describe the contribution of mitochondrial metabolism in tumorigenesis through shaping several hallmarks such as microenvironment modulation, plasticity, mitochondrial calcium, mitochondrial dynamics, and epithelial-mesenchymal transition. The review will provide a new insight into the abnormal mitochondrial metabolism in tumorigenesis, which will be conducive to tumor prevention and therapy through targeting tumor mitochondria.

Advances in seed hypoxia research

Seeds represent essential stages of the plant life cycle: embryogenesis, the intermittent quiescence phase, and germination. Each stage has its own physiological requirements, genetic program, and environmental challenges. Consequently, the effects of developmental and environmental hypoxia can vary from detrimental to beneficial. Past and recent evidence shows how low-oxygen signaling and metabolic adaptations to hypoxia affect seed development and germination. Here, we review the recent literature on seed biology in relation to hypoxia research and present our perspective on key challenges and opportunities for future investigations.

Restoring Mitochondrial Quantity and Quality to Reverse Warburg Effect and Drive Tumor Differentiation

Reduced mitochondrial quality and quantity in tumors is associated with dedifferentiation and increased malignancy. However, it remains unclear how to restore mitochondrial quantity and quality in tumors, and whether mitochondrial restoration can drive tumor differentiation. Our study shows that restoring mitochondrial function using retinoic acid (RA) to boost mitochondrial biogenesis and a mitochondrial uncoupler to enhance respiration synergistically drives neuroblastoma differentiation and inhibits proliferation. U-13C-glucose/glutamine isotope tracing revealed a metabolic shift from the pentose phosphate pathway to oxidative phosphorylation, accelerating the TCA cycle and switching substrate preference from glutamine to glucose. These effects were reversed by ETC inhibitors or in ρ0 cells lacking mtDNA, emphasizing the necessity of mitochondrial function for differentiation. Dietary RA and uncoupler treatment promoted tumor differentiation in an orthotopic neuroblastoma xenograft model, evidenced by neuropil production and Schwann cell recruitment. Single-cell RNA sequencing analysis of the orthotopic xenografts revealed that this strategy effectively eliminated the stem cell population, promoted differentiation, and increased mitochondrial gene signatures along the differentiation trajectory, which could potentially significantly improve patient outcomes. Collectively, our findings establish a mitochondria-centric therapeutic strategy for inducing tumor differentiation, suggesting that maintaining/driving differentiation in tumor requires not only ATP production but also continuous ATP consumption and sustained ETC activity.

Stimulated Emission Depletion Imaging Reveals Mitochondrial Phenotypic Heterogeneity under Apoptosis Stimuli across Living Glioma Models

The mitochondrial phenotypes contribute to the understanding of disease mechanisms and treatments, which are typically characterized through the omics methods. However, the high dynamics and phenotypic heterogeneity of mitochondria require high-resolution characterization within individual living cells. Therefore, we introduce a fluorescence analysis method, based on two-color and fluorescence lifetime stimulated emission depletion (STED) super-resolution imaging, to explore mitochondrial phenotypic heterogeneity in human (U87) and mouse (GL261) glioma models. Furthermore, we used rotenone and etoposide to simulate the effects of antitumor drugs, inducing apoptosis through mitochondrial dysfunction, respectively. The two-color labeling introduces intracellular parameters to qualitatively visualize changes in mitochondrial morphology, while fluorescence lifetime reflects the status of mitochondria and their microenvironment from the perspective of probe characteristics. This method reveals mitochondria phenotypic heterogeneity induced by the apoptotic stimuli in human and mouse glioma models from a morphological perspective.

Local glycolysis supports injury-induced axonal regeneration

Successful axonal regeneration following injury requires the effective allocation of energy. How axons withstand the initial disruption in mitochondrial energy production caused by the injury and subsequently initiate regrowth is poorly understood. Transcriptomic data showed increased expression of glycolytic genes after optic nerve crush in retinal ganglion cells with the co-deletion of Pten and Socs3. Using retinal cultures in a multicompartment microfluidic device, we observed increased regrowth and enhanced mitochondrial trafficking in the axons of Pten and Socs3 co-deleted neurons. While wild-type axons relied on mitochondrial metabolism, after injury, in the absence of Pten and Socs3, energy production was supported by local glycolysis. Specific inhibition of lactate production hindered injury survival and the initiation of regrowth while slowing down glycolysis upstream impaired regrowth initiation, axonal elongation, and energy production. Together, these observations reveal that glycolytic ATP, combined with sustained mitochondrial transport, is essential for injury-induced axonal regrowth, providing new insights into the metabolic underpinnings of axonal regeneration.

Molecular mechanisms of the specialization of human synapses in the neocortex

Synapses of the neocortex specialized during human evolution to develop over extended timescales, process vast amounts of information and increase connectivity, which is thought to underlie our advanced social and cognitive abilities. These features reflect species-specific regulations of neuron and synapse cell biology. However, despite growing understanding of the human genome and the brain transcriptome at the single-cell level, linking human-specific genetic changes to the specialization of human synapses has remained experimentally challenging. In this review, we describe recent progress in characterizing divergent morphofunctional and developmental properties of human synapses, and we discuss new insights into the underlying molecular mechanisms. We also highlight intersections between evolutionary innovations and disorder-related dysfunctions at the synapse.

Inhibiting Mitochondrial Damage for Efficient Treatment of Cerebral Ischemia-Reperfusion Injury Through Sequential Targeting Nanomedicine of Neuronal Mitochondria in Affected Brain Tissue

Oxidative stress, predominantly from neuronal mitochondrial damage and the resultant cytokine storm, is central to cerebral ischemia-reperfusion injury (CIRI). However, delivering drugs to neuronal mitochondria remains challenging due to the blood-brain barrier (BBB), which impedes drug entry into affected brain tissues. This study introduces an innovative tannic acid (TA) and melanin-modified heteropolyacid nanomedicine (MHT), which highly specifically eliminates the neuronal mitochondrial reactive oxygen radicals burst to efficiently reduce neuronal mitochondrial damage through a strategically designed sequential targeting strategy from affected brain tissue to neuronal mitochondria. TA endows MHT with sequential targeting ability by binding to matrix proteins exposed to the damaged BBB and mitochondrial outer membrane proteins of neurons, while melanin significantly enhances the antioxidant capacity of MHT. Consequently, MHT effectively inhibits neuronal apoptosis by protecting mitochondria and reversing the inflammatory immune environment through the deactivation of the cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING) pathway. MHT demonstrated a strong therapeutic effect on CIRI, with an ultralow dose (2 mg kg-1) proving effective in reversing the condition. This work not only introduces a new avenue to significantly reduce CIRI through sequential targeting therapy but also offers a new paradigm for treating other ischemia-reperfusion injury diseases.

Ancestral retrovirus envelope protein ERVWE1 upregulates circ_0001810, a potential biomarker for schizophrenia, and induces neuronal mitochondrial dysfunction via activating AK2

BACKGROUND

Increasingly studies highlight the crucial role of the ancestral retrovirus envelope protein ERVWE1 in the pathogenic mechanisms of schizophrenia, a severe psychiatric disorder affecting approximately 1% of the global population. Recent studies also underscore the significance of circular RNAs (circRNAs), crucial for neurogenesis and synaptogenesis, in maintaining neuronal functions. However, the precise relationship between ERVWE1 and circRNAs in the etiology of schizophrenia remains elusive.

RESULTS

This study observed elevated levels of hsa_circ_0001810 (circ_0001810) in the blood samples of schizophrenia patients, displaying a significant positive correlation with ERVWE1 expression. Interestingly, in vivo studies demonstrated that ERVWE1 upregulated circ_0001810 in neuronal cells. Circ_0001810, acting as a competing endogenous RNA (ceRNA), bound to miR-1197 and facilitated the release of adenylate kinase 2 (AK2). The bioinformatics analysis of the schizophrenia datasets revealed increased levels of AK2 and enrichment of mitochondrial dynamics. Notably, miR-1197 was reduced in schizophrenia patients, while AK2 levels were increased. Additionally, AK2 showed positive correlations with ERVWE1 and circ_0001810. Further studies demonstrated that AK2 led to mitochondrial dysfunction, characterized by loss of intracellular ATP, mitochondrial depolarization, and disruption of mitochondrial dynamics. Our comprehensive investigation suggested that ERVWE1 influenced ATP levels, promoted mitochondrial depolarization, and disrupted mitochondrial dynamics through the circ_0001810/AK2 pathway.

CONCLUSIONS

Circ_0001810 and AK2 were increased in schizophrenia and positively correlated with ERVWE1. Importantly, ERVWE1 triggered mitochondrial dysfunction through circ_0001810/miR-1197/AK2 pathway. Recent focus on the impact of mitochondrial dynamics on schizophrenia development had led to our discovery of a novel mechanism by which ERVWE1 contributed to the etiology of schizophrenia, particularly through mitochondrial dynamics. Moreover, these findings collectively proposed that circ_0001810 might serve as a potential blood-based biomarker for schizophrenia. Consistent with our previous theories, ERVWE1 is increasingly recognized as a promising therapeutic target for schizophrenia.

Synaptic neoteny of human cortical neurons requires species-specific balancing of SRGAP2-SYNGAP1 cross-inhibition

Human-specific (HS) genes have been implicated in brain evolution, but their impact on human neuron development and diseases remains unclear. Here, we study SRGAP2B/C, two HS gene duplications of the ancestral synaptic gene SRGAP2A, in human cortical pyramidal neurons (CPNs) xenotransplanted in the mouse cortex. Downregulation of SRGAP2B/C in human CPNs led to strongly accelerated synaptic development, indicating their requirement for the neoteny that distinguishes human synaptogenesis. SRGAP2B/C genes promoted neoteny by reducing the synaptic levels of SRGAP2A,thereby increasing the postsynaptic accumulation of the SYNGAP1 protein, encoded by a major intellectual disability/autism spectrum disorder (ID/ASD) gene. Combinatorial loss-of-function experiments in vivo revealed that the tempo of synaptogenesis is set by the reciprocal antagonism between SRGAP2A and SYNGAP1, which in human CPNs is tipped toward neoteny by SRGAP2B/C. Thus, HS genes can modify the phenotypic expression of genetic mutations leading to ID/ASD through the regulation of human synaptic neoteny.

The potential role of mitochondria in the microbiota-gut-brain axis: Implications for brain health

Mitochondria are crucial organelles that regulate cellular energy metabolism, calcium homeostasis, and oxidative stress responses, playing pivotal roles in brain development and neurodegeneration. Concurrently, the gut microbiota has emerged as a key modulator of brain physiology and pathology through the microbiota-gut-brain axis. Recent evidence suggests an intricate crosstalk between the gut microbiota and mitochondrial function, mediated by microbial metabolites that can influence mitochondrial activities in the brain. This review aims to provide a comprehensive overview of the emerging role of mitochondria as critical mediators in the microbiota-gut-brain axis, shaping brain health and neurological disease pathogenesis. We discuss how gut microbial metabolites such as short-chain fatty acids, secondary bile acids, tryptophan metabolites, and trimethylamine N-oxide can traverse the blood-brain barrier and modulate mitochondrial processes including energy production, calcium regulation, mitophagy, and oxidative stress in neurons and glial cells. Additionally, we proposed targeting the mitochondria through diet, prebiotics, probiotics, or microbial metabolites as a promising potential therapeutic approach to maintain brain health by optimizing mitochondrial fitness. Overall, further investigations into how the gut microbiota and its metabolites regulate mitochondrial bioenergetics, dynamics, and stress responses will provide valuable insights into the microbiota-gut-brain axis in both health and disease states.

miR-124 coordinates metabolic regulators acting at early stages of human neurogenesis

Metabolic dysregulation of neurons is associated with diverse human brain disorders. Metabolic reprogramming occurs during neuronal differentiation, but it is not fully understood which molecules regulate metabolic changes at the early stages of neurogenesis. In this study, we report that miR-124 is a driver of metabolic change at the initiating stage of human neurogenesis. Proteome analysis has shown the oxidative phosphorylation pathway to be the most significantly altered among the differentially expressed proteins (DEPs) in the immature neurons after the knockdown of miR-124. In agreement with these proteomics results, miR-124-depleted neurons display mitochondrial dysfunctions, such as decreased mitochondrial membrane potential and cellular respiration. Moreover, morphological analyses of mitochondria in early differentiated neurons after miR-124 knockdown result in smaller and less mature shapes. Lastly, we show the potential of identified DEPs as novel metabolic regulators in early neuronal development by validating the effects of GSTK1 on cellular respiration. GSTK1, which is upregulated most significantly in miR-124 knockdown neurons, reduces the oxygen consumption rate of neural cells. Collectively, our data highlight the roles of miR-124 in coordinating metabolic maturation at the early stages of neurogenesis and provide insights into potential metabolic regulators associated with human brain disorders characterized by metabolic dysfunctions.

Olduvai domain expression downregulates mitochondrial pathways: implications for human brain evolution and neoteny

Encoded by the NBPF gene family, Olduvai (formerly DUF1220) protein domains have undergone the largest human lineage-specific copy number expansion of any coding region in the genome. Olduvai copy number shows a linear relationship with several brain size-related measures and cortical neuron number among primates and with normal and disease-associated (micro- and macrocephaly) variation in brain size in human populations. While Olduvai domains have been shown to promote proliferation of neural stem cells, the mechanism underlying such effects has remained unclear. Here, we investigate the function of Olduvai by transcriptome and proteome analyses of cells overexpressing NBPF1, a gene encoding 7 Olduvai domains. Our results from both RNAseq and mass spectrometry approaches suggest a potential downregulation of mitochondria. In our proteomics study, a Gene Ontology (GO) enrichment analysis for the downregulated proteins revealed a striking overrepresentation of the biological process related to the mitochondrial electron transport chain (p value: 1.81e-11) and identified deregulation of the NADH dehydrogenase activity (p value: 2.43e-11) as the primary molecular function. We verify the reduction of apparent mitochondria via live-cell imaging experiments. Given these and previous Olduvai findings, we suggest that the Olduvai-mediated, dosage-dependent reduction in available energy via mitochondrial downregulation may have resulted in a developmental slowdown such that the neurogenic window among primates, and most extremely in humans, was expanded over a greater time interval, allowing for production of greater numbers of neurons and a larger brain. We further suggest that such a slowdown may extend to other developmental processes that also exhibit neotenic features.

Unraveling mechanisms of human brain evolution

Evolutionary changes in human brain structure and function have enabled our specialized cognitive abilities. How these changes have come about genetically and functionally has remained an open question. However, new methods are providing a wealth of information about the genetic, epigenetic, and transcriptomic differences that set the human brain apart. Combined with in vitro models that allow access to developing brain tissue and the cells of our closest living relatives, the puzzle pieces are now coming together to yield a much more complete picture of what is actually unique about the human brain. The challenge now will be linking these observations and making the jump from correlation to causation. However, elegant genetic manipulations are now possible and, when combined with model systems such as organoids, will uncover a mechanistic understanding of how evolutionary changes at the genetic level have led to key differences in development and function that enable human cognition.

Mitochondrion-based organellar therapies for central nervous system diseases

As most traditional drugs used to treat central nervous system (CNS) diseases have a single therapeutic target, many of them cannot treat complex diseases or diseases whose mechanism is unknown and cannot effectively reverse the root changes underlying CNS diseases. This raises the question of whether multiple functional components are involved in the complex pathological processes of CNS diseases. Organelles are the core functional units of cells, and the replacement of damaged organelles with healthy organelles allows the multitargeted and integrated modulation of cellular functions. The development of therapies that target independent functional units in the cell, specifically, organelle-based therapies, is rapidly progressing. This article comprehensively discusses the pathogenesis of mitochondrial homeostasis disorders, which involve mitochondria, one of the most important organelles in CNS diseases, and the machanisms of mitochondrion-based therapies, as well as current preclinical and clinical studies on the efficacy of therapies targeting mitochondrial to treat CNS diseases, to provide evidence for use of organelle-based treatment strategies in the future.

A Hybrid 2D-to-3D in vitro Differentiation Platform Improves Outcomes of Cerebral Cortical Organoid Generation in hiPSCs

Three-dimensional (3D) cerebral cortical organoids are popular in vitro cellular model systems widely used to study human brain development and disease, compared to traditional stem cell-derived methods that use two-dimensional (2D) monolayer cultures. Despite the advancements made in protocol development for cerebral cortical organoid derivation over the past decade, limitations due to biological, mechanistic, and technical variables remain in generating these complex 3D cellular systems. Building from our previously established differentiation system, we have made modifications to our existing 3D cerebral cortical organoid protocol that resolve several of these technical and biological challenges when working with diverse groups of human induced pluripotent stem cell (hiPSC) lines. This improved protocol blends a 2D monolayer culture format for the specification of neural stem cells and expansion of neuroepithelial progenitor cells with a 3D system for improved self-aggregation and subsequent organoid development. Furthermore, this "hybrid" approach is amenable to both an accelerated cerebral cortical organoid protocol as well as an alternative long-term differentiation protocol. In addition to establishing a hybrid technical format, this protocol also offers phenotypic and morphological characterization of stage-specific cellular profiles using antibodies and fluorescent-based dyes for live cell imaging. © 2024 Wiley Periodicals LLC. Basic Protocol 1: hiPSC-based 2D monolayer specification into neural stem cells (NSCs) Basic Protocol 2: Serial passaging and 2D monolayer expansion of neuroepithelial progenitor cells (NPCs) Support Protocol 1: Direct cryopreservation and rapid thawing of NSCs and NPCs Basic Protocol 3: Bulk aggregation of 3D neurospheres and accelerated cerebral cortical organoid differentiation Alternate Protocol 1: Bulk aggregation of 3D neurospheres and long-term cerebral cortical organoid differentiation Support Protocol 2: High-throughput 3D neurosphere formation and 2D neurosphere migration assay Support Protocol 3: LIVE/DEAD stain cell imaging assay of 3D neurospheres Support Protocol 4: NeuroFluor NeuO live cell dye for 3D cerebral cortical organoids.

Human-specific genetic modifiers of cortical architecture and function

Evolution of the cerebral cortex is thought to have been critical for the emergence of our cognitive abilities. Major features of cortical evolution include increased neuron number and connectivity and altered morpho-electric properties of cortical neurons. Significant progress has been made in identifying human-specific genetic modifiers (HSGMs), some of which are involved in shaping these features of cortical architecture. But how did these evolutionary changes support the emergence of our cognitive abilities? Here, we highlight recent studies aimed at examining the impact of HSGMs on cortical circuit function and behavior. We also discuss the need for greater insight into the link between evolution of cortical architecture and the functional and computational properties of neuronal circuits, as we seek to provide a neurobiological foundation for human cognition.

Combined small-molecule treatment accelerates maturation of human pluripotent stem cell-derived neurons

The maturation of human pluripotent stem cell (hPSC)-derived neurons mimics the protracted timing of human brain development, extending over months to years for reaching adult-like function. Prolonged in vitro maturation presents a major challenge to stem cell-based applications in modeling and treating neurological disease. Therefore, we designed a high-content imaging assay based on morphological and functional readouts in hPSC-derived cortical neurons which identified multiple compounds that drive neuronal maturation including inhibitors of lysine-specific demethylase 1 and disruptor of telomerase-like 1 and activators of calcium-dependent transcription. A cocktail of four factors, GSK2879552, EPZ-5676, N-methyl-D-aspartate and Bay K 8644, collectively termed GENtoniK, triggered maturation across all parameters tested, including synaptic density, electrophysiology and transcriptomics. Maturation effects were further validated in cortical organoids, spinal motoneurons and non-neural lineages including melanocytes and pancreatic β-cells. The effects on maturation observed across a broad range of hPSC-derived cell types indicate that some of the mechanisms controlling the timing of human maturation might be shared across lineages.

Human neural stem cell-derived artificial organelles to improve oxidative phosphorylation

Oxidative phosphorylation (OXPHOS) in the mitochondrial inner membrane is a therapeutic target in many diseases. Neural stem cells (NSCs) show progress in improving mitochondrial dysfunction in the central nervous system (CNS). However, translating neural stem cell-based therapies to the clinic is challenged by uncontrollable biological variability or heterogeneity, hindering uniform clinical safety and efficacy evaluations. We propose a systematic top-down design based on membrane self-assembly to develop neural stem cell-derived oxidative phosphorylating artificial organelles (SAOs) for targeting the central nervous system as an alternative to NSCs. We construct human conditionally immortal clone neural stem cells (iNSCs) as parent cells and use a streamlined closed operation system to prepare neural stem cell-derived highly homogenous oxidative phosphorylating artificial organelles. These artificial organelles act as biomimetic organelles to mimic respiration chain function and perform oxidative phosphorylation, thus improving ATP synthesis deficiency and rectifying excessive mitochondrial reactive oxygen species production. Conclusively, we provide a framework for a generalizable manufacturing procedure that opens promising prospects for disease treatment.

Emerging Human Pluripotent Stem Cell-Based Human-Animal Brain Chimeras for Advancing Disease Modeling and Cell Therapy for Neurological Disorders

Human pluripotent stem cell (hPSC) models provide unprecedented opportunities to study human neurological disorders by recapitulating human-specific disease mechanisms. In particular, hPSC-based human-animal brain chimeras enable the study of human cell pathophysiology in vivo. In chimeric brains, human neural and immune cells can maintain human-specific features, undergo maturation, and functionally integrate into host brains, allowing scientists to study how human cells impact neural circuits and animal behaviors. The emerging human-animal brain chimeras hold promise for modeling human brain cells and their interactions in health and disease, elucidating the disease mechanism from molecular and cellular to circuit and behavioral levels, and testing the efficacy of cell therapy interventions. Here, we discuss recent advances in the generation and applications of using human-animal chimeric brain models for the study of neurological disorders, including disease modeling and cell therapy.

Human-mouse chimeric brain models constructed from iPSC-derived brain cells: Applications and challenges

The establishment of reliable human brain models is pivotal for elucidating specific disease mechanisms and facilitating the discovery of novel therapeutic strategies for human brain disorders. Human induced pluripotent stem cell (iPSC) exhibit remarkable self-renewal capabilities and can differentiate into specialized cell types. This makes them a valuable cell source for xenogeneic or allogeneic transplantation. Human-mouse chimeric brain models constructed from iPSC-derived brain cells have emerged as valuable tools for modeling human brain diseases and exploring potential therapeutic strategies for brain disorders. Moreover, the integration and functionality of grafted stem cells has been effectively assessed using these models. Therefore, this review provides a comprehensive overview of recent progress in differentiating human iPSC into various highly specialized types of brain cells. This review evaluates the characteristics and functions of the human-mouse chimeric brain model. We highlight its potential roles in brain function and its ability to reconstruct neural circuitry in vivo. Additionally, we elucidate factors that influence the integration and differentiation of human iPSC-derived brain cells in vivo. This review further sought to provide suitable research models for cell transplantation therapy. These research models provide new insights into neuropsychiatric disorders, infectious diseases, and brain injuries, thereby advancing related clinical and academic research.