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1.
Proc Natl Acad Sci U S A ; 119(38): e2206147119, 2022 09 20.
Article in English | MEDLINE | ID: mdl-36095192

ABSTRACT

The neocortex, the center for higher brain function, first emerged in mammals and has become massively expanded and folded in humans, constituting almost half the volume of the human brain. Primary microcephaly, a developmental disorder in which the brain is smaller than normal at birth, results mainly from there being fewer neurons in the neocortex because of defects in neural progenitor cells (NPCs). Outer radial glia (oRGs), NPCs that are abundant in gyrencephalic species but rare in lissencephalic species, are thought to play key roles in the expansion and folding of the neocortex. However, how oRGs expand, whether they are necessary for neocortical folding, and whether defects in oRGs cause microcephaly remain important questions in the study of brain development, evolution, and disease. Here, we show that oRG expansion in mice, ferrets, and human cerebral organoids requires cyclin-dependent kinase 6 (CDK6), the mutation of which causes primary microcephaly via an unknown mechanism. In a mouse model in which increased Hedgehog signaling expands oRGs and intermediate progenitor cells and induces neocortical folding, CDK6 loss selectively decreased oRGs and abolished neocortical folding. Remarkably, this function of CDK6 in oRG expansion did not require its kinase activity, was not shared by the highly similar CDK4 and CDK2, and was disrupted by the mutation causing microcephaly. Therefore, our results indicate that CDK6 is conserved to promote oRG expansion, that oRGs are necessary for neocortical folding, and that defects in oRG expansion may cause primary microcephaly.


Subject(s)
Cyclin-Dependent Kinase 6 , Ependymoglial Cells , Microcephaly , Neocortex , Animals , Cyclin-Dependent Kinase 6/genetics , Cyclin-Dependent Kinase 6/metabolism , Ependymoglial Cells/cytology , Ependymoglial Cells/enzymology , Ferrets , Hedgehog Proteins/metabolism , Humans , Mice , Microcephaly/genetics , Neocortex/abnormalities , Neocortex/enzymology , Neural Stem Cells/cytology , Neural Stem Cells/enzymology , Organoids/embryology
2.
Mol Cell ; 82(1): 90-105.e13, 2022 01 06.
Article in English | MEDLINE | ID: mdl-34942119

ABSTRACT

Neurodevelopmental cognitive disorders provide insights into mechanisms of human brain development. Here, we report an intellectual disability syndrome caused by the loss of APC7, a core component of the E3 ubiquitin ligase anaphase promoting complex (APC). In mechanistic studies, we uncover a critical role for APC7 during the recruitment and ubiquitination of APC substrates. In proteomics analyses of the brain from mice harboring the patient-specific APC7 mutation, we identify the chromatin-associated protein Ki-67 as an APC7-dependent substrate of the APC in neurons. Conditional knockout of the APC coactivator protein Cdh1, but not Cdc20, leads to the accumulation of Ki-67 protein in neurons in vivo, suggesting that APC7 is required for the function of Cdh1-APC in the brain. Deregulated neuronal Ki-67 upon APC7 loss localizes predominantly to constitutive heterochromatin. Our findings define an essential function for APC7 and Cdh1-APC in neuronal heterochromatin regulation, with implications for understanding human brain development and disease.


Subject(s)
Apc7 Subunit, Anaphase-Promoting Complex-Cyclosome/metabolism , Brain/enzymology , Heterochromatin/metabolism , Intellectual Disability/enzymology , Neural Stem Cells/enzymology , Neurogenesis , Adolescent , Animals , Antigens, CD , Apc7 Subunit, Anaphase-Promoting Complex-Cyclosome/genetics , Behavior, Animal , Brain/growth & development , Cadherins/genetics , Cadherins/metabolism , Cell Line , Child , Child, Preschool , Disease Models, Animal , Female , Heterochromatin/genetics , Humans , Infant , Intellectual Disability/pathology , Intellectual Disability/physiopathology , Intellectual Disability/psychology , Intelligence , Ki-67 Antigen/genetics , Ki-67 Antigen/metabolism , Male , Mice, Inbred C57BL , Mice, Knockout , Mitosis , Mutation , Neural Stem Cells/pathology , Proteolysis , Signal Transduction , Syndrome , Ubiquitination , Young Adult
3.
Biosci Rep ; 41(12)2021 12 22.
Article in English | MEDLINE | ID: mdl-34821365

ABSTRACT

Dopamine signaling has numerous roles during brain development. In addition, alterations in dopamine signaling may be also involved in the pathophysiology of psychiatric disorders. Neurodevelopment is modulated in multiple steps by reactive oxygen species (ROS), byproducts of oxidative metabolism that are signaling factors involved in proliferation, differentiation, and migration. Hexokinase (HK), when associated with the mitochondria (mt-HK), is a potent modulator of the generation of mitochondrial ROS in the brain. In the present study, we investigated whether dopamine could affect both the activity and redox function of mt-HK in human neural progenitor cells (NPCs). We found that dopamine signaling via D1R decreases mt-HK activity and impairs ROS modulation, which is followed by an expressive release of H2O2 and impairment in calcium handling by the mitochondria. Nevertheless, mitochondrial respiration is not affected, suggesting specificity for dopamine on mt-HK function. In neural stem cells (NSCs) derived from induced-pluripotent stem cells (iPSCs) of schizophrenia patients, mt-HK is unable to decrease mitochondrial ROS, in contrast with NSCs derived from healthy individuals. Our data point to mitochondrial hexokinase as a novel target of dopaminergic signaling, as well as a redox modulator in human neural progenitor cells, which may be relevant to the pathophysiology of neurodevelopmental disorders such as schizophrenia.


Subject(s)
Dopamine/pharmacology , Hexokinase/metabolism , Mitochondria/drug effects , Neural Stem Cells/drug effects , Reactive Oxygen Species/metabolism , Receptors, Dopamine D1/agonists , Schizophrenia/enzymology , Calcium/metabolism , Case-Control Studies , Cell Line , Humans , Mitochondria/enzymology , Neural Stem Cells/enzymology , Receptors, Dopamine D1/metabolism , Signal Transduction
4.
Oxid Med Cell Longev ; 2021: 7716201, 2021.
Article in English | MEDLINE | ID: mdl-34707778

ABSTRACT

BACKGROUND: The depressive symptom hallmarks the progression of the neurodegenerative diseases, especially Alzheimer's disease. Bacterial infection is related to inflammation and depression. The present project thereby examined whether botanical drug puerarin could attenuate liposaccharide- (LPS-) induced depressive behaviors in mice. METHODS: Adult male C57BL/6N mice were sequentially treated with LPS and puerarin and evaluated for the depressive behaviors by tail suspension test and forced swim test. The brain tissues were profiled for the molecular targets of puerarin by next-generation RNA sequencing technique. Candidate targets were further verified in LPS-treated mice, neural stem cells, and highly differentiated PC12 cell line. RESULTS: Puerarin ameliorated LPS-induced depression in the mice. RNA sequencing profiles revealed that puerarin altered the expression of 16 genes while markedly downregulated Ras-related GTP-binding protein A (RagA) in LPS-treated mice. The effect of puerarin on RagA expression was confirmed by immunostaining, Western blot, and quantitative real-time PCR (qRT-PCR). Biochemical studies showed that puerarin inhibited RagA/mTOR/p70S6K pathway, attenuated the accumulation of mTORC1 in close proximity to lysosome, and reduced the production of proinflammatory cytokines. CONCLUSIONS: Botanical drug puerarin attenuated inflammation and depressive behaviors in LPS-challenged mice by inhibiting RagA/mTOR/p70S6K pathways. Puerarin may be a lead compound for the new antidepressant drugs.


Subject(s)
Antidepressive Agents/pharmacology , Behavior, Animal/drug effects , Brain/drug effects , Depression/prevention & control , Isoflavones/pharmacology , Monomeric GTP-Binding Proteins/metabolism , Ribosomal Protein S6 Kinases, 70-kDa/metabolism , TOR Serine-Threonine Kinases/metabolism , Animals , Brain/enzymology , Brain/physiopathology , Cytokines/metabolism , Depression/chemically induced , Depression/enzymology , Depression/physiopathology , Disease Models, Animal , Inflammation Mediators/metabolism , Lipopolysaccharides , Male , Mechanistic Target of Rapamycin Complex 1/metabolism , Mice, Inbred C57BL , Monomeric GTP-Binding Proteins/genetics , Neural Stem Cells/drug effects , Neural Stem Cells/enzymology , Neurons/drug effects , Neurons/enzymology , PC12 Cells , Rats , Signal Transduction
5.
Mol Cell ; 81(24): 5082-5098.e11, 2021 12 16.
Article in English | MEDLINE | ID: mdl-34699746

ABSTRACT

Cell state changes are associated with proteome remodeling to serve newly emergent cell functions. Here, we show that NGN2-driven conversion of human embryonic stem cells to induced neurons (iNeurons) is associated with increased PINK1-independent mitophagic flux that is temporally correlated with metabolic reprogramming to support oxidative phosphorylation. Global multiplex proteomics during neurogenesis revealed large-scale remodeling of functional modules linked with pluripotency, mitochondrial metabolism, and proteostasis. Differentiation-dependent mitophagic flux required BNIP3L and its LC3-interacting region (LIR) motif, and BNIP3L also promoted mitophagy in dopaminergic neurons. Proteomic analysis of ATG12-/- iNeurons revealed accumulation of endoplasmic reticulum, Golgi, and mitochondria during differentiation, indicative of widespread organelle remodeling during neurogenesis. This work reveals broad organelle remodeling of membrane-bound organelles during NGN2-driven neurogenesis via autophagy, identifies BNIP3L's central role in programmed mitophagic flux, and provides a proteomic resource for elucidating how organelle remodeling and autophagy alter the proteome during changes in cell state.


Subject(s)
Human Embryonic Stem Cells/metabolism , Membrane Proteins/metabolism , Mitochondria/enzymology , Mitophagy , Neural Stem Cells/enzymology , Neurogenesis , Neurons/enzymology , Proteome , Proto-Oncogene Proteins/metabolism , Tumor Suppressor Proteins/metabolism , Autophagy-Related Protein 12/genetics , Autophagy-Related Protein 12/metabolism , Cell Line , Humans , Membrane Proteins/genetics , Mitochondria/genetics , Protein Interaction Domains and Motifs , Protein Kinases/genetics , Protein Kinases/metabolism , Proteostasis , Proto-Oncogene Proteins/genetics , Time Factors , Tumor Suppressor Proteins/genetics
6.
Cell Rep ; 37(3): 109864, 2021 10 19.
Article in English | MEDLINE | ID: mdl-34686322

ABSTRACT

Increasing evidence suggests that neurodevelopmental alterations might contribute to increase the susceptibility to develop neurodegenerative diseases. We investigate the occurrence of developmental abnormalities in dopaminergic neurons in a model of Parkinson's disease (PD). We monitor the differentiation of human patient-specific neuroepithelial stem cells (NESCs) into dopaminergic neurons. Using high-throughput image analyses and single-cell RNA sequencing, we observe that the PD-associated LRRK2-G2019S mutation alters the initial phase of neuronal differentiation by accelerating cell-cycle exit with a concomitant increase in cell death. We identify the NESC-specific core regulatory circuit and a molecular mechanism underlying the observed phenotypes. The expression of NR2F1, a key transcription factor involved in neurogenesis, decreases in LRRK2-G2019S NESCs, neurons, and midbrain organoids compared to controls. We also observe accelerated dopaminergic differentiation in vivo in NR2F1-deficient mouse embryos. This suggests a pathogenic mechanism involving the LRRK2-G2019S mutation, where the dynamics of dopaminergic differentiation are modified via NR2F1.


Subject(s)
Brain/enzymology , COUP Transcription Factor I/metabolism , Dopaminergic Neurons/enzymology , Induced Pluripotent Stem Cells/enzymology , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Neural Stem Cells/enzymology , Neurogenesis , Parkinson Disease/enzymology , Animals , Brain/pathology , COUP Transcription Factor I/genetics , Cell Cycle , Cell Line , Cell Proliferation , Cell Survival , Dopaminergic Neurons/pathology , Female , Humans , Induced Pluripotent Stem Cells/pathology , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics , Male , Mice, 129 Strain , Mice, Knockout , Mutation , Neural Stem Cells/pathology , Parkinson Disease/genetics , Parkinson Disease/pathology , Phenotype , RNA-Seq , Signal Transduction , Single-Cell Analysis , Time Factors
7.
Elife ; 102021 09 30.
Article in English | MEDLINE | ID: mdl-34590578

ABSTRACT

Astrocytes are essential cells of the central nervous system, characterized by dynamic relationships with neurons that range from functional metabolic interactions and regulation of neuronal firing activities, to the release of neurotrophic and neuroprotective factors. In Parkinson's disease (PD), dopaminergic neurons are progressively lost during the course of the disease, but the effects of PD on astrocytes and astrocyte-to-neuron communication remain largely unknown. This study focuses on the effects of the PD-related mutation LRRK2 G2019S in astrocytes generated from patient-derived induced pluripotent stem cells. We report the alteration of extracellular vesicle (EV) biogenesis in astrocytes and identify the abnormal accumulation of key PD-related proteins within multivesicular bodies (MVBs). We found that dopaminergic neurons internalize astrocyte-secreted EVs and that LRRK2 G2019S EVs are abnormally enriched in neurites and fail to provide full neurotrophic support to dopaminergic neurons. Thus, dysfunctional astrocyte-to-neuron communication via altered EV biological properties may participate in the progression of PD.


Subject(s)
Astrocytes/enzymology , Cell Communication , Dopaminergic Neurons/enzymology , Exosomes/enzymology , Induced Pluripotent Stem Cells/enzymology , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/metabolism , Neural Stem Cells/enzymology , Parkinson Disease/enzymology , Animals , Astrocytes/ultrastructure , Atrophy , Case-Control Studies , Cell Line , Dopaminergic Neurons/pathology , Endocytosis , Exosomes/genetics , Exosomes/ultrastructure , Humans , Induced Pluripotent Stem Cells/ultrastructure , Leucine-Rich Repeat Serine-Threonine Protein Kinase-2/genetics , Mice, Inbred C57BL , Mice, Transgenic , Mutation , Neural Stem Cells/ultrastructure , Organelle Biogenesis , Parkinson Disease/genetics , Parkinson Disease/pathology
8.
Cell Death Dis ; 12(7): 700, 2021 07 14.
Article in English | MEDLINE | ID: mdl-34262022

ABSTRACT

Proper development of the mammalian cerebral cortex relies on precise gene expression regulation, which is controlled by genetic, epigenetic, and epitranscriptomic factors. Here we generate RNA demethylase Fto and methyltransferase Mettl3 cortical-specific conditional knockout mice, and detect severe brain defects caused by Mettl3 deletion but not Fto knockout. Transcriptomic profiles using RNA sequencing indicate that knockout of Mettl3 causes a more dramatic alteration on gene transcription than that of Fto. Interestingly, we conduct ribosome profiling sequencing, and find that knockout of Mettl3 leads to a more severe disruption of translational regulation of mRNAs than deletion of Fto and results in altered translation of crucial genes in cortical radial glial cells and intermediate progenitors. Moreover, Mettl3 deletion causes elevated translation of a significant number of mRNAs, in particular major components in m6A methylation. Our findings indicate distinct functions of Mettl3 and Fto in brain development, and uncover a profound role of Mettl3 in regulating translation of major mRNAs that control proper cortical development.


Subject(s)
Alpha-Ketoglutarate-Dependent Dioxygenase FTO/metabolism , Cerebral Cortex/enzymology , Gene Expression Regulation, Developmental , Methyltransferases/metabolism , Protein Biosynthesis , Transcription, Genetic , Alpha-Ketoglutarate-Dependent Dioxygenase FTO/genetics , Animals , Cerebral Cortex/embryology , Gestational Age , Methylation , Methyltransferases/genetics , Mice, 129 Strain , Mice, Inbred C57BL , Mice, Knockout , Neural Stem Cells/enzymology , Neural Stem Cells/pathology , Neurogenesis , Neuroglia/enzymology , Neuroglia/pathology , RNA Processing, Post-Transcriptional , Transcriptome
9.
Elife ; 102021 05 27.
Article in English | MEDLINE | ID: mdl-34042046

ABSTRACT

Sphingolipids are important structural components of cell membranes and prominent signaling molecules controlling cell growth, differentiation, and apoptosis. Sphingolipids are particularly abundant in the brain, and defects in sphingolipid degradation are associated with several human neurodegenerative diseases. However, molecular mechanisms governing sphingolipid metabolism remain unclear. Here, we report that sphingolipid degradation is under transcriptional control of SIRT1, a highly conserved mammalian NAD+-dependent protein deacetylase, in mouse embryonic stem cells (mESCs). Deletion of SIRT1 results in accumulation of sphingomyelin in mESCs, primarily due to reduction of SMPDL3B, a GPI-anchored plasma membrane bound sphingomyelin phosphodiesterase. Mechanistically, SIRT1 regulates transcription of Smpdl3b through c-Myc. Functionally, SIRT1 deficiency-induced accumulation of sphingomyelin increases membrane fluidity and impairs neural differentiation in vitro and in vivo. Our findings discover a key regulatory mechanism for sphingolipid homeostasis and neural differentiation, further imply that pharmacological manipulation of SIRT1-mediated sphingomyelin degradation might be beneficial for treatment of human neurological diseases.


All cells in the brain start life as stem cells which are yet to have a defined role in the body. A wide range of molecules and chemical signals guide stem cells towards a neuronal fate, including a group of molecules called sphingolipids. These molecules sit in the membrane surrounding the cell and play a pivotal role in a number of processes which help keep the neuronal cell healthy. Various enzymes work together to break down sphingolipids and remove them from the membrane. Defects in these enzymes can result in excess levels of sphingolipids, which can lead to neurodegenerative diseases, such as Alzheimer's, Parkinson's and Huntington's disease. But how these enzymes are used and controlled during neuronal development is still somewhat of a mystery. To help answer this question, Fan et al. studied an enzyme called SIRT1 which has been shown to alleviate symptoms in animal models of neurodegenerative diseases. Stem cells were extracted from a mouse embryo lacking the gene for SIRT1 and cultured in the laboratory. These faulty cells were found to have superfluous amounts of sphingolipids, which made their membranes more fluid and reduced their ability to develop into neuronal cells. Further investigation revealed that SIRT1 regulates the degradation of sphingolipids by promoting the production of another enzyme called SMPDL3B. Fan et al. also found that when female mice were fed a high-fat diet, this caused sphingolipids to accumulate in their embryos which lacked the gene for SIRT1; this, in turn, impaired the neural development of their offspring. These findings suggest that targeting SIRT1 may offer new strategies for treating neurological diseases. The discovery that embryos deficient in SIRT1 are sensitive to high-fat diets implies that activating this enzyme might attenuate some of the neonatal complications associated with maternal obesity.


Subject(s)
Cyclic Nucleotide Phosphodiesterases, Type 3/metabolism , Mouse Embryonic Stem Cells/enzymology , Neural Stem Cells/enzymology , Neurogenesis , Proto-Oncogene Proteins c-myc/metabolism , Sirtuin 1/metabolism , Sphingolipids/metabolism , Animals , Cell Line , Cyclic Nucleotide Phosphodiesterases, Type 3/genetics , Gene Expression Regulation, Developmental , Mice , Mice, Inbred C57BL , Mice, Knockout , Proto-Oncogene Proteins c-myc/genetics , Signal Transduction , Sirtuin 1/genetics , Transcription, Genetic
10.
Mol Biotechnol ; 63(1): 53-62, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33130996

ABSTRACT

The repressor element 1 (RE1) silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF) modulates the expression of genes with RE1/neuron-restrictive silencing element (RE1/NRSE) sites by recruiting the switch independent 3 (SIN3) factor and the REST corepressor (COREST) to its N and C-terminal repressor domain, respectively. Both, SIN3 and COREST assemble into protein complexes that are composed of multiple subunits including a druggable histone deacetylase (HDAC) enzyme. The SIN3 core complex comprises the eponymous proteins SIN3A or SIN3B, the catalytically active proteins HDAC1 or HDAC2, the histone chaperone retinoblastoma-associated protein 46/retinoblastoma-binding protein 7 (RBAP46/RBBP7) or RBAP48/RBBP4, the SIN3-associated protein 30 (SAP30), and the suppressor of defective silencing 3 (SDS3). Here, we overcome a bottleneck limiting the molecular characterization of the REST/NRSF-SIN3 transcriptional corepressor complex. To this end, SIN3 genes were amplified from the complementary DNA of neural stem/progenitor cells, and expressed in a baculovirus/insect cell expression system. We show that the isolates bind to DNA harboring RE1/NRSE sites and demonstrate that the histone deacetylase activity is blocked by small-molecule inhibitors. Thus, our isolates open up for future biomedical research on this critical transcriptional repressor complex and are envisioned as tool for drug testing.


Subject(s)
Co-Repressor Proteins/genetics , Histone Deacetylase Inhibitors/pharmacology , Nerve Tissue Proteins/genetics , Neural Stem Cells/metabolism , Repressor Proteins/genetics , Sin3 Histone Deacetylase and Corepressor Complex/genetics , Sin3 Histone Deacetylase and Corepressor Complex/isolation & purification , Animals , Baculoviridae/metabolism , Benzamides/pharmacology , Co-Repressor Proteins/isolation & purification , Co-Repressor Proteins/metabolism , Depsipeptides/pharmacology , Gene Library , Histone Deacetylases/metabolism , Humans , Nerve Tissue Proteins/isolation & purification , Nerve Tissue Proteins/metabolism , Neural Stem Cells/enzymology , Pyrimidines/pharmacology , Recombinant Proteins , Regulatory Elements, Transcriptional/genetics , Repressor Proteins/isolation & purification , Repressor Proteins/metabolism , Sf9 Cells , Sin3 Histone Deacetylase and Corepressor Complex/metabolism
11.
Stem Cells Dev ; 29(23): 1497-1509, 2020 12 01.
Article in English | MEDLINE | ID: mdl-33040644

ABSTRACT

Human neural stem cells (hNSCs) have long been used as an in vitro model to study neurogenesis and as candidates for nervous system therapy. Many parameters have been considered when evaluating the success of transplantation, but sex of donor and recipients is often not discussed. We investigated two commercial NSC lines, the female hNSC-H9 and male hNSC-H14, and we observed faster growth rates in the male cells. At 4 days of differentiation, male cells presented a significant increase in expression of DCX, an immature neuronal marker, while female cells showed a significant increase in RMST, a long noncoding RNA, which is indispensable during neurogenesis. In addition, expression of neural markers MAP2, PSD95, SYP, DCX, and TUJ1 at day 14 of differentiation suggested a similar differentiation potential in both lines. The most significant differences at day 14 of differentiation were the expression levels of RELN, with almost 100-fold difference between the sexes, and MASH1, with more than 1,000-fold increase in male cells. To evaluate whether some of the observed differences may be sex related, we measured the expression of gametologous genes located on the X- and Y-chromosome. Most noticeable was the increase of Y-encoded demethylases KDM6C (UTY) and KDM5D during differentiation of male cells. Our results indicate that attention should be paid to sex when planning neurogenesis and transplantation experiments.


Subject(s)
Cell Differentiation , Chromosomes, Human, Y/genetics , Gene Expression Regulation, Enzymologic , Histone Demethylases/genetics , Minor Histocompatibility Antigens/genetics , Minor Histocompatibility Antigens/metabolism , Neural Stem Cells/cytology , Neural Stem Cells/enzymology , Nuclear Proteins/metabolism , Biomarkers/metabolism , Cell Differentiation/genetics , Cell Line , Cell Proliferation , Cell Shape , Chromosomes, Human, X/genetics , Female , Histone Demethylases/metabolism , Humans , Male , Nuclear Proteins/genetics , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Reelin Protein , Reference Standards
12.
Viruses ; 12(9)2020 09 08.
Article in English | MEDLINE | ID: mdl-32911874

ABSTRACT

Since the global outbreak of SARS-CoV-2 (COVID-19), infections of diverse human organs along with multiple symptoms continue to be reported. However, the susceptibility of the brain to SARS-CoV-2, and the mechanisms underlying neurological infection are still elusive. Here, we utilized human embryonic stem cell-derived brain organoids and monolayer cortical neurons to investigate infection of brain with pseudotyped SARS-CoV-2 viral particles. Spike-containing SARS-CoV-2 pseudovirus infected neural layers within brain organoids. The expression of ACE2, a host cell receptor for SARS-CoV-2, was sustained during the development of brain organoids, especially in the somas of mature neurons, while remaining rare in neural stem cells. However, pseudotyped SARS-CoV-2 was observed in the axon of neurons, which lack ACE2. Neural infectivity of SARS-CoV-2 pseudovirus did not increase in proportion to viral load, but only 10% of neurons were infected. Our findings demonstrate that brain organoids provide a useful model for investigating SARS-CoV-2 entry into the human brain and elucidating the susceptibility of the brain to SARS-CoV-2.


Subject(s)
Betacoronavirus/physiology , Neurons/virology , Organoids/virology , Prosencephalon/virology , Spike Glycoprotein, Coronavirus/physiology , Angiotensin-Converting Enzyme 2 , Axons/enzymology , Cell Differentiation , Cells, Cultured , Cerebral Cortex/cytology , Embryonic Stem Cells/virology , HEK293 Cells , Humans , Nerve Tissue Proteins/physiology , Neural Stem Cells/enzymology , Neural Stem Cells/virology , Neurons/enzymology , Peptidyl-Dipeptidase A/physiology , Prosencephalon/cytology , Receptors, Virus/physiology , SARS-CoV-2 , Viral Load , Viral Tropism , Virus Internalization
13.
Epigenomics ; 12(19): 1725-1738, 2020 10.
Article in English | MEDLINE | ID: mdl-32896160

ABSTRACT

Aim: To identify lncRNAs targeting GSK3ß in MDD. Materials & methods: The levels of GSK3ß and its three targeting lncRNAs (gsk3ß antisense AS1, AS2 and AS3) were detected in 52 patients with major depressive disorder (MDD) before and after 8 weeks of escitalopram treatment. The functional study was evaluated using the silence of lncR-gsk3ßAS2/3. The correlation between lncRNA-gsk3ß and 89 MDD patients was analyzed. Human neuron progenitor cells were used to investigate the functional role of lncRNA-gsk3ß in MDD. Results: All three lncRNAs were downregulated in MDD patients but upregulated after treatment. Inhibition of gsk3ßAS2/3 reduced GSK3ß expression and its phosphorylation levels in the neuron progenitor cells. Conclusion: Our findings suggest that lncRNA-gsk3ßAS3 regulates GSK3ß activity in MDD and has potential as a novel therapeutic target.


Subject(s)
Depressive Disorder, Major/genetics , Gene Expression Regulation, Enzymologic , Glycogen Synthase Kinase 3 beta/genetics , RNA, Long Noncoding/metabolism , Adult , Cells, Cultured , Depressive Disorder, Major/diagnosis , Depressive Disorder, Major/enzymology , Depressive Disorder, Major/metabolism , Glycogen Synthase Kinase 3 beta/metabolism , Humans , Middle Aged , Neural Stem Cells/enzymology , Neural Stem Cells/metabolism , RNA, Antisense/metabolism
14.
Biochem Biophys Res Commun ; 532(4): 541-547, 2020 11 19.
Article in English | MEDLINE | ID: mdl-32896380

ABSTRACT

The proper development of the cerebral cortex is essential for brain formation and functioning. O-GlcNAcylation, an important posttranslational modification, regulates the pathways critical for neuronal health and the survival of the cerebral cortex in neurodegenerative diseases. However, the role of O-GlcNAcylation in regulating cerebral cortical development at the embryonic and early postnatal (0-21 days) stages is still largely unknown. Here we report that the selective deletion of O-GlcNAc transferase (OGT) in neural stem cells (NSCs) in mice led to a series of severe brain developmental deficits, including dramatic shrinkage of cortical and hippocampal histoarchitecture, widespread neuronal apoptosis, decrease in cell proliferation, induction of endoplasmic reticulum (ER) stress, and inhibition of neuronal dendritic and axonal differentiation. The pathology of corticogenesis deficits caused by OGT deletion may largely rely on complicated biological processes, such as proliferation, apoptosis and differentiation. Our results suggest that dysfunctional O-GlcNAcylation in NSCs may be an important contributor to neurodevelopmental diseases.


Subject(s)
Cerebral Cortex/growth & development , N-Acetylglucosaminyltransferases/physiology , Neural Stem Cells/enzymology , Animals , Apoptosis , Axons/ultrastructure , Cerebral Cortex/anatomy & histology , Cerebral Cortex/embryology , Cerebral Cortex/enzymology , Dendrites/ultrastructure , Disks Large Homolog 4 Protein/metabolism , Endoplasmic Reticulum Stress , Male , Mice, Knockout , Morphogenesis , Multipotent Stem Cells/enzymology , N-Acetylglucosaminyltransferases/genetics , Neurons/cytology , Neurons/metabolism
15.
Pharmacol Res ; 159: 105049, 2020 09.
Article in English | MEDLINE | ID: mdl-32598944

ABSTRACT

Brachial plexus axotomy is a common peripheral nerve trauma. Artemisinin, an FDA-approved antimalarial drug, has been described to possess neuroprotective properties. However, the specific mechanisms by which artemisinin protects neurons from axotomy-induced neurotoxicity remain to be elucidated. In this study, we assessed the neuroprotective effects of artemisinin on an experimental animal model of brachial plexus injury and explored the possible mechanisms involved. Artemisinin treatment restored both athletic ability and sensation of the affected upper limb, rescued motoneurons and attenuated the inflammatory response in the ventral horn of the spinal cord. Additionally, artemisinin inhibited the molecular signals of apoptosis, activated signaling pathways related to cell survival and induced NSCPs differentiation into NeuN-positive neurons. Further validation of the involved key signaling molecules, using an in vitro model of hydrogen peroxide-induced neurotoxicity, revealed that both the inhibition of PKA signaling pathway or the silencing of Akt reversed the neuroprotective action of artemisinin on motoneurons. Our results indicate that artemisinin provides neuroprotection against axotomy and hydrogen peroxide-induced neurotoxicity, an effect that might be mediated by the PKA-Akt signaling pathway.


Subject(s)
Apoptosis/drug effects , Artemisinins/pharmacology , Cyclic AMP-Dependent Protein Kinases/metabolism , DNA-Binding Proteins/metabolism , Motor Neurons/drug effects , Nerve Tissue Proteins/metabolism , Neural Stem Cells/drug effects , Neurogenesis/drug effects , Neuroprotective Agents/pharmacology , Peripheral Nerve Injuries/drug therapy , Proto-Oncogene Proteins c-akt/metabolism , Spinal Cord/drug effects , Animals , Axotomy , Behavior, Animal/drug effects , Brachial Plexus/surgery , Cells, Cultured , Disease Models, Animal , Mice, Inbred C57BL , Motor Neurons/enzymology , Motor Neurons/pathology , Neural Stem Cells/enzymology , Neural Stem Cells/pathology , Peripheral Nerve Injuries/enzymology , Peripheral Nerve Injuries/pathology , Peripheral Nerve Injuries/physiopathology , Phosphorylation , Recovery of Function , Signal Transduction , Spinal Cord/enzymology , Spinal Cord/pathology , Spinal Cord/physiopathology
16.
J Alzheimers Dis ; 75(4): 1361-1376, 2020.
Article in English | MEDLINE | ID: mdl-32390638

ABSTRACT

BACKGROUND: Porphyromonas gingivalis (P. gingivalis) and its gingipain virulence factors have been identified as pathogenic effectors in Alzheimer's disease (AD). In a recent study we demonstrated the presence of gingipains in over 90% of postmortem AD brains, with gingipains localizing to the cytoplasm of neurons. However, infection of neurons by P. gingivalis has not been previously reported. OBJECTIVE: To demonstrate intraneuronal P. gingivalis and gingipain expression in vitro after infecting neurons derived from human inducible pluripotent stem cells (iPSC) with P. gingivalis for 24, 48, and 72 h. METHODS: Infection was characterized by transmission electron microscopy, confocal microscopy, and bacterial colony forming unit assays. Gingipain expression was monitored by immunofluorescence and RT-qPCR, and protease activity monitored with activity-based probes. Neurodegenerative endpoints were assessed by immunofluorescence, western blot, and ELISA. RESULTS: Neurons survived the initial infection and showed time dependent, infection induced cell death. P. gingivalis was found free in the cytoplasm or in lysosomes. Infected neurons displayed an accumulation of autophagic vacuoles and multivesicular bodies. Tau protein was strongly degraded, and phosphorylation increased at T231. Over time, the density of presynaptic boutons was decreased. CONCLUSION: P. gingivalis can invade and persist in mature neurons. Infected neurons display signs of AD-like neuropathology including the accumulation of autophagic vacuoles and multivesicular bodies, cytoskeleton disruption, an increase in phospho-tau/tau ratio, and synapse loss. Infection of iPSC-derived mature neurons by P. gingivalis provides a novel model system to study the cellular mechanisms leading to AD and to investigate the potential of new therapeutic approaches.


Subject(s)
Alzheimer Disease/microbiology , Alzheimer Disease/pathology , Bacteroidaceae Infections/complications , Gingipain Cysteine Endopeptidases/metabolism , Neurons/microbiology , Neurons/pathology , Alzheimer Disease/enzymology , Animals , Cells, Cultured , Mice , Neural Stem Cells/enzymology , Neural Stem Cells/microbiology , Neural Stem Cells/pathology , Neurons/enzymology , Porphyromonas gingivalis
17.
Mol Cell ; 77(5): 1124-1142.e10, 2020 03 05.
Article in English | MEDLINE | ID: mdl-32142685

ABSTRACT

The ubiquitin ligase Parkin, protein kinase PINK1, USP30 deubiquitylase, and p97 segregase function together to regulate turnover of damaged mitochondria via mitophagy, but our mechanistic understanding in neurons is limited. Here, we combine induced neurons (iNeurons) derived from embryonic stem cells with quantitative proteomics to reveal the dynamics and specificity of Parkin-dependent ubiquitylation under endogenous expression conditions. Targets showing elevated ubiquitylation in USP30-/- iNeurons are concentrated in components of the mitochondrial translocon, and the ubiquitylation kinetics of the vast majority of Parkin targets are unaffected, correlating with a modest kinetic acceleration in accumulation of pS65-Ub and mitophagic flux upon mitochondrial depolarization without USP30. Basally, ubiquitylated translocon import substrates accumulate, suggesting a quality control function for USP30. p97 was dispensable for Parkin ligase activity in iNeurons. This work provides an unprecedented quantitative landscape of the Parkin-modified ubiquitylome in iNeurons and reveals the underlying specificity of central regulatory elements in the pathway.


Subject(s)
Human Embryonic Stem Cells/enzymology , Mitochondria/enzymology , Mitochondrial Proteins/metabolism , Mitophagy , Neural Stem Cells/enzymology , Neurogenesis , Neurons/enzymology , Thiolester Hydrolases/metabolism , Ubiquitin-Protein Ligases/metabolism , HeLa Cells , Human Embryonic Stem Cells/pathology , Humans , Kinetics , Mitochondria/genetics , Mitochondria/pathology , Mitochondrial Proteins/genetics , Neural Stem Cells/pathology , Neurons/pathology , Phosphorylation , Protein Kinases/genetics , Protein Kinases/metabolism , Proteomics , Signal Transduction , Thiolester Hydrolases/genetics , Ubiquitin-Protein Ligases/genetics , Ubiquitination , Valosin Containing Protein/genetics , Valosin Containing Protein/metabolism
18.
JCI Insight ; 5(4)2020 02 27.
Article in English | MEDLINE | ID: mdl-31990683

ABSTRACT

Lesch-Nyhan disease (LND) is a rare monogenic disease caused by deficiency of the salvage pathway enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT). LND is characterized by severe neuropsychiatric symptoms that currently cannot be treated. Predictive in vivo models are lacking for screening and evaluating candidate drugs because LND-associated neurological symptoms are not recapitulated in HGPRT-deficient animals. Here, we used human neural stem cells and neurons derived from induced pluripotent stem cells (iPSCs) of children affected with LND to identify neural phenotypes of interest associated with HGPRT deficiency to develop a target-agnostic-based drug screening system. We screened more than 3000 molecules and identified 6 pharmacological compounds, all possessing an adenosine moiety, that corrected HGPRT deficiency-associated neuronal phenotypes by promoting metabolism compensations in an HGPRT-independent manner. This included S-adenosylmethionine, a compound that had already been used as a compassionate approach to ease the neuropsychiatric symptoms in LND. Interestingly, these compounds compensate abnormal metabolism in a manner complementary to the gold standard allopurinol and can be provided to patients with LND via simple food supplementation. This experimental paradigm can be easily adapted to other metabolic disorders affecting normal brain development and functioning in the absence of a relevant animal model.


Subject(s)
Induced Pluripotent Stem Cells/cytology , Lesch-Nyhan Syndrome/drug therapy , Lesch-Nyhan Syndrome/therapy , Neural Stem Cells/cytology , Allopurinol/therapeutic use , Animals , Case-Control Studies , Cell Differentiation , Disease Models, Animal , Humans , Hypoxanthine Phosphoribosyltransferase/genetics , Neural Stem Cells/enzymology , Phenotype
19.
J Cell Biochem ; 121(2): 1586-1598, 2020 02.
Article in English | MEDLINE | ID: mdl-31512776

ABSTRACT

Stem cells that express therapeutic proteins have been identified to have an anticancer effects on various types of cancer. In the present study study, human neural stem cells (hNSCs) that were genetically engineered to express cytosine deaminase (CD) and human interferon-ß (IFN-ß) were used for anaplastic thyroid cancer (ATC) treatment owing to their tumor-tropic properties and therapeutic effects. CD is an enzyme that converts 5-fluorocytosine (5-FC), a prodrug, to 5-fluorouracil (5-FU) which is a medication to suppress tumor growth through DNA synthesis inhibition. Also, IFN-ß suppresses tumor growth by the induction of apoptotic process. In water soluble tetrazolium salt (WST) assay, SNU-80 cells which are human female ATC cells were cocultured with three cell types including engineered hNSCs such as HB1.F3, HB1.F3.CD, and HB1.F3.CD.IFN-ß cells on transwells and treated with 5-FC for 72 hours. Finally, the SNU-80 cell viability was reduced by the coculture with HB1.F3.CD and HB1.F3.CD.IFN-ß cells. In dichlorofluorescein diacetate (DCF-DA) and TdT-mediated dUTP nick-end labeling (TUNEL) assays, the production of reactive oxygen species (ROS) and the number of apoptotic cells were increased by HB1.F3.CD and HB1.F3.CD.IFN-ß cells in the presence of 5-FC. In Western blot assay, ROS, and apoptosis-related genes were increased in SNU-80 cells when they were cocultured with HB1.F3.CD and HB1.F3.CD.IFN-ß cells. In transwell migration assay, hNSCs selectively migrated to SNU-80 cells because hNSCs interacted with chemoattractant factors like SDF-1α, uPAR, and CCR2 secreted by SNU-80 cells. Taken together, engineered hNSCs were revealed to selectively migrate to ATC cells and to inhibit growth as well as to induce apoptosis of ATC cells via ROS production through the actions of transgenes such as CD and IFN-ß. Therefore, these engineered hNSCs can be promising candidates for the treatment of metastatic ATC.


Subject(s)
Cytosine Deaminase/metabolism , Flucytosine , Gene Expression , Neural Stem Cells/enzymology , Thyroid Carcinoma, Anaplastic , Cell Line, Tumor , Coculture Techniques , Cytosine Deaminase/genetics , Flucytosine/pharmacokinetics , Flucytosine/pharmacology , Humans , Prodrugs/pharmacokinetics , Prodrugs/pharmacology , Thyroid Carcinoma, Anaplastic/metabolism , Thyroid Carcinoma, Anaplastic/pathology , Thyroid Carcinoma, Anaplastic/therapy , Thyroid Neoplasms/metabolism , Thyroid Neoplasms/pathology , Thyroid Neoplasms/therapy
20.
J Clin Invest ; 130(3): 1431-1445, 2020 03 02.
Article in English | MEDLINE | ID: mdl-31794431

ABSTRACT

Epigenetic integrity is critical for many eukaryotic cellular processes. An important question is how different epigenetic regulators control development and influence disease. Lysine acetyltransferase 8 (KAT8) is critical for acetylation of histone H4 at lysine 16 (H4K16), an evolutionarily conserved epigenetic mark. It is unclear what roles KAT8 plays in cerebral development and human disease. Here, we report that cerebrum-specific knockout mice displayed cerebral hypoplasia in the neocortex and hippocampus, along with improper neural stem and progenitor cell (NSPC) development. Mutant cerebrocortical neuroepithelia exhibited faulty proliferation, aberrant neurogenesis, massive apoptosis, and scant H4K16 propionylation. Mutant NSPCs formed poor neurospheres, and pharmacological KAT8 inhibition abolished neurosphere formation. Moreover, we describe KAT8 variants in 9 patients with intellectual disability, seizures, autism, dysmorphisms, and other anomalies. The variants altered chromobarrel and catalytic domains of KAT8, thereby impairing nucleosomal H4K16 acetylation. Valproate was effective for treating epilepsy in at least 2 of the individuals. This study uncovers a critical role of KAT8 in cerebral and NSPC development, identifies 9 individuals with KAT8 variants, and links deficient H4K16 acylation directly to intellectual disability, epilepsy, and other developmental anomalies.


Subject(s)
Hippocampus/enzymology , Histone Acetyltransferases/metabolism , Intellectual Disability/enzymology , Neocortex/enzymology , Neural Stem Cells/enzymology , Acetylation , Animals , HEK293 Cells , Hippocampus/pathology , Histone Acetyltransferases/genetics , Humans , Intellectual Disability/pathology , Mice , Mice, Knockout , Neocortex/pathology , Neural Stem Cells/pathology , Nucleosomes/genetics , Nucleosomes/metabolism
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