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1.
Acta Histochem Cytochem ; 57(3): 89-100, 2024 Jun 28.
Article in English | MEDLINE | ID: mdl-38988694

ABSTRACT

Neural stem/progenitor cells (NSPCs) in specific brain regions require precisely regulated metabolite production during critical development periods. Purines-vital components of DNA, RNA, and energy carriers like ATP and GTP-are crucial metabolites in brain development. Purine levels are tightly controlled through two pathways: de novo synthesis and salvage synthesis. Enzymes driving de novo pathway are assembled into a large multienzyme complex termed the "purinosome." Here, we review purine metabolism and purinosomes as spatiotemporal regulators of neural development. Notably, around postnatal day 0 (P0) during mouse cortical development, purine synthesis transitions from the de novo pathway to the salvage pathway. Inhibiting the de novo pathway affects mTORC1 pathway and leads to specific forebrain malformations. In this review, we also explore the importance of protein-protein interactions of a newly identified NSPC protein-NACHT and WD repeat domain-containing 1 (Nwd1)-in purinosome formation. Reduced Nwd1 expression disrupts purinosome formation, impacting NSPC proliferation and neuronal migration, resulting in periventricular heterotopia. Nwd1 interacts directly with phosphoribosylaminoimidazole-succinocarboxamide synthetase (PAICS), an enzyme involved in de novo purine synthesis. We anticipate this review will be valuable for researchers investigating neural development, purine metabolism, and protein-protein interactions.

2.
Nutrients ; 16(11)2024 Jun 06.
Article in English | MEDLINE | ID: mdl-38892717

ABSTRACT

The placenta is the largest fetal organ, which connects the mother to the fetus and supports most aspects of organogenesis through the transport of nutrients and gases. However, further studies are needed to assess placental pathology as a reliable predictor of long-term physical growth or neural development in newborns. The Consensus Statement of the Amsterdam Placental Workshop Group (APWGCS) on the sampling and definition of placental lesions has resulted in diagnostic uniformity in describing the most common pathological lesions of the placenta and contributed to the international standardization of descriptions of placental pathology. In this narrative review, we reclassified descriptions of placental pathology from previously published papers according to the APWGCS criteria and comparatively assessed the relationship with infantile physical and/or neural development. After reclassification and reevaluation, placental pathology of maternal vascular malperfusion, one of the APWGCS criteria, emerged as a promising candidate as a universal predictor of negative infantile neurodevelopmental outcomes, not only in term and preterm deliveries but also in high-risk groups of very low birthweight newborns. However, there are few studies that examined placental pathology according to the full categories of APWGCS and also included low-risk general infants. It is necessary to incorporate the assessment of placental pathology utilizing APWGCS in the design of future birth cohort studies as well as in follow-up investigations of high-risk infants.


Subject(s)
Consensus , Placenta , Humans , Pregnancy , Female , Placenta/pathology , Infant, Newborn , Placenta Diseases/pathology , Placenta Diseases/diagnosis , Child Development , Infant , Netherlands
3.
Neurosci Biobehav Rev ; 163: 105744, 2024 May 31.
Article in English | MEDLINE | ID: mdl-38825259

ABSTRACT

Every species' brain, body and behavior is shaped by the contingencies of their evolutionary history; these exert pressures that change their developmental trajectories. There is, however, another set of contingencies that shape us and other animals: those that occur during a lifetime. In this perspective piece, we show how these two histories are intertwined by focusing on the individual. We suggest that organisms--their brains and behaviors--are not solely the developmental products of genes and neural circuitry but individual centers of action unfolding in time. To unpack this idea, we first emphasize the importance of variation and the central role of the individual in biology. We then go over "errors in time" that we often make when comparing development across species. Next, we reveal how an individual's development is a process rather than a product by presenting a set of case studies. These show developmental trajectories as emerging in the contexts of the "the actual now" and "the presence of the past". Our consideration reveals that individuals are slippery-they are never static; they are a set of on-going, creative activities. In light of this, it seems that taking individual development seriously is essential if we aspire to make meaningful comparisons of neural circuits and behavior within and across species.

4.
bioRxiv ; 2024 May 23.
Article in English | MEDLINE | ID: mdl-38826254

ABSTRACT

Background: Increasing evidence suggests that a substantial proportion of disease-associated mutations occur in enhancers, regions of non-coding DNA essential to gene regulation. Understanding the structures and mechanisms of regulatory programs this variation affects can shed light on the apparatuses of human diseases. Results: We collected epigenetic and gene expression datasets from seven early time points during neural differentiation. Focusing on this model system, we constructed networks of enhancer-promoter interactions, each at an individual stage of neural induction. These networks served as the base for a rich series of analyses, through which we demonstrated their temporal dynamics and enrichment for various disease-associated variants. We applied the Girvan-Newman clustering algorithm to these networks to reveal biologically relevant substructures of regulation. Additionally, we demonstrated methods to validate predicted enhancer-promoter interactions using transcription factor overexpression and massively parallel reporter assays. Conclusions: Our findings suggest a generalizable framework for exploring gene regulatory programs and their dynamics across developmental processes. This includes a comprehensive approach to studying the effects of disease-associated variation on transcriptional networks. The techniques applied to our networks have been published alongside our findings as a computational tool, E-P-INAnalyzer. Our procedure can be utilized across different cellular contexts and disorders.

5.
G3 (Bethesda) ; 2024 Jun 13.
Article in English | MEDLINE | ID: mdl-38869246

ABSTRACT

This study investigated the dominant blue eyes (DBE) trait linked to hearing impairment and variable white spotting in Maine Coon cats. Fifty-eight animals descending from two different DBE lineages, the Dutch and the Topaz lines, were sampled. They comprised 48 cats from the Dutch bloodline, including 9 green-eyed and 31 blue-eyed cats, with some individuals exhibiting signs of deafness, and 8 stillborn kittens. Samples from the Topaz lineage included ten blue-eyed animals. A brainstem auditory evoked potential test (BAER) revealed a reduced to absent response to auditory stimuli and absent physiological waveforms in all of the eight examined DBE animals. We sequenced the genome of two affected cats from the Dutch line and searched for variants in 19 candidate genes for the human Waardenburg syndrome and pigmentary disorders. This search yielded nine private protein-changing candidate variants in the genes PAX3, EDN3, KIT, OCA2, SLC24A5, HERC2 and TYRP1. The genotype-phenotype co-segregation was observed for the PAX3 variant within all animals from the Dutch lineage. The mutant allele was absent from 461 control genomes and 241 additionally genotyped green-eyed Maine Coons. We considered the PAX3 variant as the most plausible candidate -a heterozygous nonsense single basepair substitution in exon 6 of PAX3 (NC_051841.1: g.205,787,310G>A, XM_019838731.3:c.937C>T, XP_019694290.1:p.Gln313*), predicted to result in a premature stop codon. PAX3 variants cause auditory-pigmentary syndrome in humans, horses, and mice. Together with the comparative data from other species, our findings strongly suggest PAX3:c.937C>T (OMIA:001688-9685) as the most likely candidate variant for the DBE, deafness and minimal white spotting in the Maine Coon Dutch line. Finally, we propose the designation of DBERE (Rociri Elvis Dominant Blue Eyes) allele in the domestic cat.

6.
Front Neural Circuits ; 18: 1409680, 2024.
Article in English | MEDLINE | ID: mdl-38860141

ABSTRACT

The brain constructs spatially organized sensory maps to represent sensory information. The formation of sensory maps has traditionally been thought to depend on synchronous neuronal activity. However, recent evidence from the olfactory system suggests that cell type-specific temporal patterns of spontaneous activity play an instructive role in shaping the olfactory glomerular map. These findings challenge traditional views and highlight the importance of investigating the spatiotemporal dynamics of neural activity to understand the development of complex neural circuits. This review discusses the implications of new findings in the olfactory system and outlines future research directions.


Subject(s)
Olfactory Pathways , Animals , Olfactory Pathways/physiology , Olfactory Pathways/cytology , Humans , Nerve Net/physiology , Neurons/physiology , Olfactory Bulb/physiology , Olfactory Bulb/cytology
7.
Cell Rep ; 43(6): 114339, 2024 Jun 25.
Article in English | MEDLINE | ID: mdl-38852158

ABSTRACT

Quiescent adult neural stem cells (NSCs) in the mammalian brain arise from proliferating NSCs during development. Beyond acquisition of quiescence, an adult NSC hallmark, little is known about the process, milestones, and mechanisms underlying the transition of developmental NSCs to an adult NSC state. Here, we performed targeted single-cell RNA-seq analysis to reveal the molecular cascade underlying NSC development in the early postnatal mouse dentate gyrus. We identified two sequential steps, first a transition to quiescence followed by further maturation, each of which involved distinct changes in metabolic gene expression. Direct metabolic analysis uncovered distinct milestones, including an autophagy burst before NSC quiescence acquisition and cellular reactive oxygen species level elevation along NSC maturation. Functionally, autophagy is important for the NSC transition to quiescence during early postnatal development. Together, our study reveals a multi-step process with defined milestones underlying establishment of the adult NSC pool in the mammalian brain.


Subject(s)
Autophagy , Hippocampus , Neural Stem Cells , Neural Stem Cells/metabolism , Neural Stem Cells/cytology , Animals , Mice , Hippocampus/metabolism , Hippocampus/cytology , Neurogenesis , Dentate Gyrus/metabolism , Dentate Gyrus/cytology , Dentate Gyrus/growth & development , Cell Differentiation , Mice, Inbred C57BL , Reactive Oxygen Species/metabolism , Adult Stem Cells/metabolism , Adult Stem Cells/cytology , Single-Cell Analysis , Cell Proliferation
8.
Dev Biol ; 2024 Jun 27.
Article in English | MEDLINE | ID: mdl-38944329

ABSTRACT

During neural development, sculpting of early formed circuits by cell death and synaptic pruning is necessary to generate a functional and efficient nervous system. This allows for the establishment of rudimentary circuits which necessitate early organism survival to later undergo subsequent refinement. These changes facilitate additional specificity to stimuli which can lead to increased behavioral complexity. In multiple species, Rohon-Beard neurons (RBs) are the earliest mechanosensory neurons specified and are critical in establishing a rudimentary motor response circuit. Sensory input from RBs gradually becomes redundant as dorsal root ganglion (DRG) neurons develop and integrate into motor circuits. Previous studies demonstrate that RBs undergo a dramatic wave of cell death concurrent with development of the DRG. However, contrary to these studies, we show that neurogenin1+ (ngn1) RBs do not undergo a widespread wave of programmed cell death during early zebrafish development and instead persist until at least 15 days post fertilization (dpf). Starting at 2 dpf, we also observed a dramatic medialization and shrinkage of ngn1+ RB somas along with a gradual downregulation of ngn1 in RBs. This alters a fundamental premise of early zebrafish neural development and opens new avenues to explore mechanisms of RB function, persistence, and circuit refinement.

9.
Trends Neurosci ; 47(7): 491-505, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38897852

ABSTRACT

While many core biological processes are conserved across species, the human brain has evolved with unique capacities. Current understanding of the neurobiological mechanisms that endow human traits as well as associated vulnerabilities remains limited. However, emerging data have illuminated species divergence in DNA elements and genome organization, in molecular, morphological, and functional features of conserved neural cell types, as well as temporal differences in brain development. Here, we summarize recent data on unique features of the human brain and their complex implications for the study and treatment of brain diseases. We also consider key outstanding questions in the field and discuss the technologies and foundational knowledge that will be required to accelerate understanding of human neurobiology.


Subject(s)
Brain , Humans , Brain/physiology , Animals , Genomics/methods , Biological Evolution
10.
Dev Neurobiol ; 2024 Jun 03.
Article in English | MEDLINE | ID: mdl-38830696

ABSTRACT

Formation of the corpus callosum (CC), anterior commissure (AC), and postoptic commissure (POC), connecting the left and right cerebral hemispheres, is crucial for cerebral functioning. Collapsin response mediator protein 2 (CRMP2) has been suggested to be associated with the mechanisms governing this formation, based on knockout studies in mice and knockdown/knockout studies in zebrafish. Previously, we reported two cases of non-synonymous CRMP2 variants with S14R and R565C substitutions. Among the, the R565C substitution (p.R565C) was caused by the novel CRMP2 mutation c.1693C > T, and the patient presented with intellectual disability accompanied by CC hypoplasia. In this study, we demonstrate that crmp2 mRNA could rescue AC and POC formation in crmp2-knockdown zebrafish, whereas the mRNA with the R566C mutation could not. Zebrafish CRMP2 R566C corresponds to human CRMP2 R565C. Further experiments with transfected cultured cells indicated that CRMP2 with the R566C mutation could not bind to kinesin light chain 1 (KLC1). Knockdown of klc1a in zebrafish resulted in defective AC and POC formation, revealing a genetic interaction with crmp2. These findings suggest that the CRMP2 R566C mutant fails to bind to KLC1, preventing axonal elongation and leading to defective AC and POC formation in zebrafish and CC formation defects in humans. Our study highlights the importance of the interaction between CRMP2 and KLC1 in the formation of the forebrain commissures, revealing a novel mechanism associated with CRMP2 mutations underlying human neurodevelopmental abnormalities.

11.
Neural Dev ; 19(1): 4, 2024 May 02.
Article in English | MEDLINE | ID: mdl-38698415

ABSTRACT

BACKGROUND: The evolution of central nervous systems (CNSs) is a fascinating and complex topic; further work is needed to understand the genetic and developmental homology between organisms with a CNS. Research into a limited number of species suggests that CNSs may be homologous across Bilateria. This hypothesis is based in part on similar functions of BMP signaling in establishing fates along the dorsal-ventral (D-V) axis, including limiting neural specification to one ectodermal region. From an evolutionary-developmental perspective, the best way to understand a system is to explore it in a wide range of organisms to create a full picture. METHODS: Here, we expand our understanding of BMP signaling in Spiralia, the third major clade of bilaterians, by examining phenotypes after expression of a dominant-negative BMP Receptor 1 and after knock-down of the putative BMP antagonist Chordin-like using CRISPR/Cas9 gene editing in the annelid Capitella teleta (Pleistoannelida). RESULTS: Ectopic expression of the dominant-negative Ct-BMPR1 did not increase CNS tissue or alter overall D-V axis formation in the trunk. Instead, we observed a unique asymmetrical phenotype: a distinct loss of left tissues, including the left eye, brain, foregut, and trunk mesoderm. Adding ectopic BMP4 early during cleavage stages reversed the dominant-negative Ct-BMPR1 phenotype, leading to a similar loss or reduction of right tissues instead. Surprisingly, a similar asymmetrical loss of left tissues was evident from CRISPR knock-down of Ct-Chordin-like but concentrated in the trunk rather than the episphere. CONCLUSIONS: Our data highlight a novel asymmetrical phenotype, giving us further insight into the complicated story of BMP's developmental role. We further solidify the hypothesis that the function of BMP signaling during the establishment of the D-V axis and CNS is fundamentally different in at least Pleistoannelida, possibly in Spiralia, and is not required for nervous system delimitation in this group.


Subject(s)
Biological Evolution , Bone Morphogenetic Protein Receptors, Type I , Animals , Bone Morphogenetic Protein Receptors, Type I/genetics , Bone Morphogenetic Protein Receptors, Type I/metabolism , Body Patterning/genetics , Body Patterning/physiology , Signal Transduction/physiology
12.
Front Nutr ; 11: 1349738, 2024.
Article in English | MEDLINE | ID: mdl-38706562

ABSTRACT

Introduction: Macronutrient intake can be one of the most influential factors in cognitive and neural development in adolescents. Adolescence is a specific period of cognitive and neural development, and nutritional effects during this period could be life-long. Therefore, understanding the effects of macronutrient intake on cognitive and neural development in adolescents is crucially important. We thus examined the association across macronutrient intake, intelligence, and neural development using population-based cohort data. Methods: We conducted two studies. In study 1, we included a total of 1,734 participants (boys, 907, age [mean ± standard deviation] 171.9 ± 3.44 months; range 163.0-186.0 months) from the Tokyo TEEN Cohort (TTC) to examine the association between macronutrient intake and intelligence quotient (IQ). In study 2, we included a total of 63 participants (boys, 38, age 174.4 ± 7.7 months; range 160.7-191.6 months) to investigate the effect of nutrition intake on neural development using graph theory analysis for resting-state functional magnetic resonance imaging (rs-fMRI) derived from a subset of the TTC. Results: TTC data revealed that a higher IQ was associated in boys with increased protein intake (ß = 0.068, p = 0.031), and in girls, with reduced carbohydrate intake (ß = -0.076, p = 0.024). Graph theory analysis for rs-fMRI at approximately age 12 has shown that impaired local efficiency in the left inferior frontal gyrus was associated with higher carbohydrate and fat intake ([x, y, z] = [-51, 23, 8], pFDR-corrected = 0.00018 and 0.02290, respectively), whereas increased betweenness centrality in the left middle temporal gyrus was associated with higher carbohydrate, fat, and protein intake ([x, y, z] = [-61, -43, -13], pFDR-corrected = 0.0027, 0.0029, and 0.00075, respectively). Moreover, we identified a significant moderating effect of fat and protein intake on the relationship between change in betweenness centrality over a 2-year measurement gap in the left middle temporal gyrus and intelligence (ß = 12.41, p = 0.0457; ß = 12.12, p = 0.0401, respectively). Conclusion: Our study showed the association between macronutrient intake and neural development related to intelligence in early adolescents. Appropriate nutritional intake would be a key factor for healthy cognitive and neural development.

13.
Cells ; 13(5)2024 Feb 27.
Article in English | MEDLINE | ID: mdl-38474374

ABSTRACT

Mitochondria, the energy suppliers of the cells, play a central role in a variety of cellular processes essential for survival or leading to cell death. Consequently, mitochondrial dysfunction is implicated in numerous general and CNS disorders. The clinical manifestations of mitochondrial dysfunction include metabolic disorders, dysfunction of the immune system, tumorigenesis, and neuronal and behavioral abnormalities. In this review, we focus on the mitochondrial role in the CNS, which has unique characteristics and is therefore highly dependent on the mitochondria. First, we review the role of mitochondria in neuronal development, synaptogenesis, plasticity, and behavior as well as their adaptation to the intricate connections between the different cell types in the brain. Then, we review the sparse knowledge of the mechanisms of exogenous mitochondrial uptake and describe attempts to determine their half-life and transplantation long-term effects on neuronal sprouting, cellular proteome, and behavior. We further discuss the potential of mitochondrial transplantation to serve as a tool to study the causal link between mitochondria and neuronal activity and behavior. Next, we describe mitochondrial transplantation's therapeutic potential in various CNS disorders. Finally, we discuss the basic and reverse-translation challenges of this approach that currently hinder the clinical use of mitochondrial transplantation.


Subject(s)
Central Nervous System Diseases , Mitochondrial Diseases , Humans , Mitochondria/metabolism , Central Nervous System/metabolism , Brain/metabolism , Central Nervous System Diseases/metabolism , Mitochondrial Diseases/metabolism
14.
Dev Cell ; 59(9): 1132-1145.e6, 2024 May 06.
Article in English | MEDLINE | ID: mdl-38531357

ABSTRACT

Neurons must be made in the correct proportions to communicate with the appropriate synaptic partners and form functional circuits. In the Drosophila visual system, multiple subtypes of distal medulla (Dm) inhibitory interneurons are made in distinct, reproducible numbers-from 5 to 800 per optic lobe. These neurons are born from a crescent-shaped neuroepithelium called the outer proliferation center (OPC), which can be subdivided into specific domains based on transcription factor and growth factor expression. We fate mapped Dm neurons and found that more abundant neural types are born from larger neuroepithelial subdomains, while less abundant subtypes are born from smaller ones. Additionally, morphogenetic Dpp/BMP signaling provides a second layer of patterning that subdivides the neuroepithelium into smaller domains to provide more granular control of cell proportions. Apoptosis appears to play a minor role in regulating Dm neuron abundance. This work describes an underappreciated mechanism for the regulation of neuronal stoichiometry.


Subject(s)
Drosophila Proteins , Drosophila melanogaster , Neurons , Animals , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Neurons/metabolism , Neurons/cytology , Drosophila melanogaster/metabolism , Optic Lobe, Nonmammalian/metabolism , Optic Lobe, Nonmammalian/cytology , Signal Transduction , Visual Pathways/metabolism , Apoptosis , Bone Morphogenetic Proteins/metabolism , Body Patterning , Interneurons/metabolism , Interneurons/cytology , Gene Expression Regulation, Developmental , Cell Count , Cell Proliferation , Neurogenesis/physiology
15.
In Vitro Cell Dev Biol Anim ; 60(5): 544-554, 2024 May.
Article in English | MEDLINE | ID: mdl-38386235

ABSTRACT

As humans' closest living relatives, chimpanzees offer valuable insights into human evolution. However, technical and ethical limitations hinder investigations into the molecular and cellular foundations that distinguish chimpanzee and human traits. Recently, induced pluripotent stem cells (iPSCs) have emerged as a novel model for functional comparative studies and provided a non-invasive alternative for studying embryonic phenomena. In this study, we generated five new chimpanzee iPSC lines from peripheral blood cells and skin fibroblasts with SeV vectors carrying four reprogramming factors (human OCT3/4, SOX2, KLF4, and L-MYC) and characterized their pluripotency and differentiation potential. We also examined the expression of a human-specific non-coding RNA, HSTR1, which is predicted to be involved in human brain development. Our results show that the chimpanzee iPSCs possess pluripotent characteristics and can differentiate into various cell lineages. Moreover, we found that HSTR1 is expressed in human iPSCs and their neural derivatives but not in chimpanzee counterparts, supporting its possible role in human-specific brain development. As iPSCs are inherently variable due to genetic and epigenetic differences in donor cells or reprogramming procedures, it is essential to expand the number of chimpanzee iPSC lines to comprehensively capture the molecular and cellular properties representative of chimpanzees. Hence, our cells provide a valuable resource for investigating the function and regulation of human-specific transcripts such as HSTR1 and for understanding human evolution more generally.


Subject(s)
Cell Differentiation , Induced Pluripotent Stem Cells , Kruppel-Like Factor 4 , Pan troglodytes , Animals , Induced Pluripotent Stem Cells/cytology , Induced Pluripotent Stem Cells/metabolism , Cell Differentiation/genetics , Humans , Cell Line , Species Specificity , Fibroblasts/cytology , Fibroblasts/metabolism , Cellular Reprogramming/genetics
16.
Dev Cell ; 59(4): 482-495.e6, 2024 Feb 26.
Article in English | MEDLINE | ID: mdl-38272027

ABSTRACT

Mutations or dysregulation of nucleoporins (Nups) are strongly associated with neural developmental diseases, yet the underlying mechanisms remain poorly understood. Here, we show that depletion of Nup Seh1 in radial glial progenitors results in defective neural progenitor proliferation and differentiation that ultimately manifests in impaired neurogenesis and microcephaly. This loss of stem cell proliferation is not associated with defects in the nucleocytoplasmic transport. Rather, transcriptome analysis showed that ablation of Seh1 in neural stem cells derepresses the expression of p21, and knockdown of p21 partially restored self-renewal capacity. Mechanistically, Seh1 cooperates with the NuRD transcription repressor complex at the nuclear periphery to regulate p21 expression. Together, these findings identified that Nups regulate brain development by exerting a chromatin-associated role and affecting neural stem cell proliferation.


Subject(s)
Neocortex , Neural Stem Cells , Animals , Mice , Cell Differentiation , Gene Expression , Neocortex/metabolism , Nuclear Pore Complex Proteins/genetics , Nuclear Pore Complex Proteins/metabolism
17.
Pediatr Exerc Sci ; 36(1): 23-29, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-37553109

ABSTRACT

The present study aimed to clarify the development of motor unit (MU) firing properties and the association between those neural properties and force steadiness (FS)/neurological tests in 6- to 12-year-old children. Fifty-eight school-aged children performed maximal voluntary knee extension contraction, a submaximal FS test at 10% of maximal voluntary knee extension contraction, knee extension reaction time to light stimulus test, and single-leg standing test, and data from 38 children who passed the criteria were subject to analysis. During the FS test, high-density surface electromyography was recorded from the vastus lateralis muscle to identify individual MU firing activity. FS was improved with an increase in age (r = -.540, P < .001). The MU firing rate (MUFR) was significantly decreased with an increase in age (r = -.343, P = .035). MUFR variability was not associated with age. Although there was no significant correlation between FS and MUFR, FS was significantly correlated with MUFR variability even after adjustment for the effect of age (r = .551, P = .002). Neither the reaction time nor the single-leg standing test was correlated with any MU firing properties. These findings suggest that MUFR variability makes an important contribution to precise force control in children but does not naturally develop with age.


Subject(s)
Isometric Contraction , Quadriceps Muscle , Child , Humans , Isometric Contraction/physiology , Electromyography , Quadriceps Muscle/physiology , Knee/physiology , Muscle, Skeletal/physiology , Muscle Contraction/physiology
18.
Dev Neurosci ; 46(1): 1-21, 2024.
Article in English | MEDLINE | ID: mdl-37231803

ABSTRACT

The genesis of a mature complement of neurons is thought to require, at least in part, precursor cell lineages in which neural progenitors have distinct identities recognized by exclusive expression of one or a few molecular markers. Nevertheless, limited progenitor types distinguished by specific markers and lineal progression through such subclasses cannot easily yield the magnitude of neuronal diversity in most regions of the nervous system. The late Verne Caviness, to whom this edition of Developmental Neuroscience is dedicated, recognized this mismatch. In his pioneering work on the histogenesis of the cerebral cortex, he acknowledged the additional flexibility required to generate multiple classes of cortical projection and interneurons. This flexibility may be accomplished by establishing cell states in which levels rather than binary expression or repression of individual genes vary across each progenitor's shared transcriptome. Such states may reflect local, stochastic signaling via soluble factors or coincidence of cell surface ligand/receptor pairs in subsets of neighboring progenitors. This probabilistic, rather than determined, signaling could modify transcription levels via multiple pathways within an apparently uniform population of progenitors. Progenitor states, therefore, rather than lineal relationships between types may underlie the generation of neuronal diversity in most regions of the nervous system. Moreover, mechanisms that influence variation required for flexible progenitor states may be targets for pathological changes in a broad range of neurodevelopmental disorders, especially those with polygenic origins.


Subject(s)
Neurodevelopmental Disorders , Neurons , Male , Humans , Neurons/metabolism , Cerebral Cortex/metabolism , Cell Lineage/physiology , Neurodevelopmental Disorders/genetics , Neurodevelopmental Disorders/metabolism , Signal Transduction , Neurogenesis/physiology , Cell Differentiation/physiology
19.
Dev Neurosci ; 46(1): 55-68, 2024.
Article in English | MEDLINE | ID: mdl-37231858

ABSTRACT

Neonatal hypoxic-ischemic encephalopathy (HIE) is the leading cause of acquired neonatal brain injury with the risk of developing serious neurological sequelae and death. An accurate and robust prediction of short- and long-term outcomes may provide clinicians and families with fundamental evidence for their decision-making, the design of treatment strategies, and the discussion of developmental intervention plans after discharge. Diffusion tensor imaging (DTI) is one of the most powerful neuroimaging tools with which to predict the prognosis of neonatal HIE by providing microscopic features that cannot be assessed by conventional magnetic resonance imaging (MRI). DTI provides various scalar measures that represent the properties of the tissue, such as fractional anisotropy (FA) and mean diffusivity (MD). Since the characteristics of the diffusion of water molecules represented by these measures are affected by the microscopic cellular and extracellular environment, such as the orientation of structural components and cell density, they are often used to study the normal developmental trajectory of the brain and as indicators of various tissue damage, including HIE-related pathologies, such as cytotoxic edema, vascular edema, inflammation, cell death, and Wallerian degeneration. Previous studies have demonstrated widespread alteration in DTI measurements in severe cases of HIE and more localized changes in neonates with mild-to-moderate HIE. In an attempt to establish cutoff values to predict the occurrence of neurological sequelae, MD and FA measurements in the corpus callosum, thalamus, basal ganglia, corticospinal tract, and frontal white matter have proven to have an excellent ability to predict severe neurological outcomes. In addition, a recent study has suggested that a data-driven, unbiased approach using machine learning techniques on features obtained from whole-brain image quantification may accurately predict the prognosis of HIE, including for mild-to-moderate cases. Further efforts are needed to overcome current challenges, such as MRI infrastructure, diffusion modeling methods, and data harmonization for clinical application. In addition, external validation of predictive models is essential for clinical application of DTI to prognostication.


Subject(s)
Diffusion Tensor Imaging , Hypoxia-Ischemia, Brain , Infant, Newborn , Humans , Diffusion Tensor Imaging/methods , Prognosis , Hypoxia-Ischemia, Brain/pathology , Diffusion Magnetic Resonance Imaging/methods , Magnetic Resonance Imaging/methods , Brain/diagnostic imaging , Brain/pathology , Edema/complications , Edema/pathology
20.
J Cell Physiol ; 239(1): 152-165, 2024 Jan.
Article in English | MEDLINE | ID: mdl-37991435

ABSTRACT

Polycomb repressive complexes (PRCs) play critical roles in cell fate decisions during normal development as well as disease progression through mediating histone modifications such as H3K27me3 and H2AK119ub. How exactly PRCs recruited to chromatin remains to be fully illuminated. Here, we report that YTHDF1, the N6-methyladenine (m6 A) RNA reader that was previously known to be mainly cytoplasmic, associates with RNF2, a PRC1 protein that mediates H2AK119ub in human embryonic stem cells (hESCs). A portion of YTHDF1 localizes in the nuclei and associates with RNF2/H2AK119ub on a subset of gene loci related to neural development functions. Knock-down YTHDF1 attenuates H2AK119ub modification on these genes and promotes neural differentiation in hESCs. Our findings provide a noncanonical mechanism that YTHDF1 participates in PRC1 functions in hESCs.


Subject(s)
Cell Cycle Proteins , Human Embryonic Stem Cells , RNA-Binding Proteins , Humans , Cell Cycle Proteins/genetics , Cell Cycle Proteins/metabolism , Chromatin , Human Embryonic Stem Cells/metabolism , Polycomb Repressive Complex 1/genetics , Polycomb Repressive Complex 1/metabolism , Polycomb-Group Proteins/genetics , Polycomb-Group Proteins/metabolism , Protein Processing, Post-Translational , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Histones/genetics , Histones/metabolism
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