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1.
Mol Psychiatry ; 2024 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-38499656

RESUMO

Autism spectrum disorder (ASD) is a major neurodevelopmental disorder affecting 1 in 36 children in the United States. While neurons have been the focus of understanding ASD, an altered neuro-immune response in the brain may be closely associated with ASD, and a neuro-immune interaction could play a role in the disease progression. As the resident immune cells of the brain, microglia regulate brain development and homeostasis via core functions including phagocytosis of synapses. While ASD has been traditionally considered a polygenic disorder, recent large-scale human genetic studies have identified SCN2A deficiency as a leading monogenic cause of ASD and intellectual disability. We generated a Scn2a-deficient mouse model, which displays major behavioral and neuronal phenotypes. However, the role of microglia in this disease model is unknown. Here, we reported that Scn2a-deficient mice have impaired learning and memory, accompanied by reduced synaptic transmission and lower spine density in neurons of the hippocampus. Microglia in Scn2a-deficient mice are partially activated, exerting excessive phagocytic pruning of post-synapses related to the complement C3 cascades during selective developmental stages. The ablation of microglia using PLX3397 partially restores synaptic transmission and spine density. To extend our findings from rodents to human cells, we established a microglia-incorporated human cerebral organoid model carrying an SCN2A protein-truncating mutation identified in children with ASD. We found that human microglia display increased elimination of post-synapse in cerebral organoids carrying the SCN2A mutation. Our study establishes a key role of microglia in multi-species autism-associated models of SCN2A deficiency from mouse to human cells.

2.
Proc Natl Acad Sci U S A ; 119(29): e2205166119, 2022 07 19.
Artigo em Inglês | MEDLINE | ID: mdl-35858349

RESUMO

Chromatin motions depend on and may regulate genome functions, in particular the DNA damage response. In yeast, DNA double-strand breaks (DSBs) globally increase chromatin diffusion, whereas in higher eukaryotes the impact of DSBs on chromatin dynamics is more nuanced. We mapped the motions of chromatin microdomains in mammalian cells using diffractive optics and photoactivatable chromatin probes and found a high level of spatial heterogeneity. DNA damage reduces heterogeneity and imposes spatially defined shifts in motions: Distal to DNA breaks, chromatin motions are globally reduced, whereas chromatin retains higher mobility at break sites. These effects are driven by context-dependent changes in chromatin compaction. Photoactivated lattices of chromatin microdomains are ideal to quantify microscale coupling of chromatin motion. We measured correlation distances up to 2 µm in the cell nucleus, spanning chromosome territories, and speculate that this correlation distance between chromatin microdomains corresponds to the physical separation of A and B compartments identified in chromosome conformation capture experiments. After DNA damage, chromatin motions become less correlated, a phenomenon driven by phase separation at DSBs. Our data indicate tight spatial control of chromatin motions after genomic insults, which may facilitate repair at the break sites and prevent deleterious contacts of DSBs, thereby reducing the risk of genomic rearrangements.


Assuntos
Montagem e Desmontagem da Cromatina , Cromatina , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Animais , Cromatina/química , Cromossomos , Saccharomyces cerevisiae/genética
3.
J Biol Chem ; 299(8): 105023, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37423307

RESUMO

Exposure to environmental chemicals such as lead (Pb) during vulnerable developmental periods can result in adverse health outcomes later in life. Human cohort studies have demonstrated associations between developmental Pb exposure and Alzheimer's disease (AD) onset in later life which were further corroborated by findings from animal studies. The molecular pathway linking developmental Pb exposure and increased AD risk, however, remains elusive. In this work, we used human iPSC-derived cortical neurons as a model system to study the effects of Pb exposure on AD-like pathogenesis in human cortical neurons. We exposed neural progenitor cells derived from human iPSC to 0, 15, and 50 ppb Pb for 48 h, removed Pb-containing medium, and further differentiated them into cortical neurons. Immunofluorescence, Western blotting, RNA-sequencing, ELISA, and FRET reporter cell lines were used to determine changes in AD-like pathogenesis in differentiated cortical neurons. Exposing neural progenitor cells to low-dose Pb, mimicking a developmental exposure, can result in altered neurite morphology. Differentiated neurons exhibit altered calcium homeostasis, synaptic plasticity, and epigenetic landscape along with elevated AD-like pathogenesis markers, including phosphorylated tau, tau aggregates, and Aß42/40. Collectively, our findings provide an evidence base for Ca dysregulation caused by developmental Pb exposure as a plausible molecular mechanism accounting for increased AD risk in populations with developmental Pb exposure.


Assuntos
Doença de Alzheimer , Células-Tronco Pluripotentes Induzidas , Chumbo , Animais , Humanos , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Homeostase , Células-Tronco Pluripotentes Induzidas/patologia , Chumbo/toxicidade , Neurônios/patologia
4.
J Am Chem Soc ; 145(44): 23963-23971, 2023 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-37897810

RESUMO

Two-dimensional (2D) metal organic chalcogenides (MOCs) such as silver phenylselenolate (AgSePh) have emerged as a new class of 2D materials due to their unique optical properties. However, these materials typically exhibit large band gaps, and their elemental and structural versatility remain significantly limited. In this work, we synthesize a new family of 2D lead organic chalcogenide (LOC) materials with excellent structural and dimensionality tunability by designing the bonding ability of the organic molecules and the stereochemical activity of the Pb lone pair. The introduction of electron-donating substituents on the benzenethiol ligands results in a series of LOCs that transition from 1D to 2D, featuring reduced band gaps (down to 1.7 eV), broadband emission, and strong electron-phonon coupling. We demonstrated a prototypical single crystal photodetector with 2D LOC that showed the dimensionality engineering on the transport property of LOC semiconductors. This study paves the way for further development of the synthesis and optical properties of novel organic-inorganic hybrid 2D materials.

5.
J Neurosci ; 41(49): 10194-10208, 2021 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-34716231

RESUMO

With the wide adoption of genomic sequencing in children having seizures, an increasing number of SCN2A genetic variants have been revealed as genetic causes of epilepsy. Voltage-gated sodium channel Nav1.2, encoded by gene SCN2A, is predominantly expressed in the pyramidal excitatory neurons and supports action potential (AP) firing. One recurrent SCN2A genetic variant is L1342P, which was identified in multiple patients with epileptic encephalopathy and intractable seizures. However, the mechanism underlying L1342P-mediated seizures and the pharmacogenetics of this variant in human neurons remain unknown. To understand the core phenotypes of the L1342P variant in human neurons, we took advantage of a reference human-induced pluripotent stem cell (hiPSC) line from a male donor, in which L1342P was introduced by CRISPR/Cas9-mediated genome editing. Using patch-clamping and microelectrode array (MEA) recordings, we revealed that cortical neurons derived from hiPSCs carrying heterozygous L1342P variant have significantly increased intrinsic excitability, higher sodium current density, and enhanced bursting and synchronous network firing, suggesting hyperexcitability phenotypes. Interestingly, L1342P neuronal culture displayed a degree of resistance to the anticonvulsant medication phenytoin, which recapitulated aspects of clinical observation of patients carrying the L1342P variant. In contrast, phrixotoxin-3 (PTx3), a Nav1.2 isoform-specific blocker, can potently alleviate spontaneous and chemically-induced hyperexcitability of neurons carrying the L1342P variant. Our results reveal a possible pathogenic underpinning of Nav1.2-L1342P mediated epileptic seizures and demonstrate the utility of genome-edited hiPSCs as an in vitro platform to advance personalized phenotyping and drug discovery.SIGNIFICANCE STATEMENT A mounting number of SCN2A genetic variants have been identified from patients with epilepsy, but how SCN2A variants affect the function of human neurons contributing to seizures is still elusive. This study investigated the functional consequences of a recurring SCN2A variant (L1342P) using human iPSC-derived neurons and revealed both intrinsic and network hyperexcitability of neurons carrying a mutant Nav1.2 channel. Importantly, this study recapitulated elements of clinical observations of drug-resistant features of the L1342P variant, and provided a platform for in vitro drug testing. Our study sheds light on cellular mechanism of seizures resulting from a recurring Nav1.2 variant, and helps to advance personalized drug discovery to treat patients carrying pathogenic SCN2A variant.


Assuntos
Epilepsia/genética , Epilepsia/fisiopatologia , Edição de Genes/métodos , Canal de Sódio Disparado por Voltagem NAV1.2/genética , Neurônios/patologia , Córtex Cerebral/fisiopatologia , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Células-Tronco Pluripotentes Induzidas/fisiologia , Mutação
6.
Cytometry A ; 101(4): 339-350, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35001539

RESUMO

The epigenetic signature of cancer cells varies with disease progression and drug treatment, necessitating the study of these modifications with single cell resolution over time. The rapid detection and sorting of cells based on their underlying epigenetic modifications by flow cytometry can enable single cell measurement and tracking to understand tumor heterogeneity and progression warranting the development of a live-cell compatible epigenome probes. In this work, we developed epigenetic probes based on bimolecular fluorescence complementation (BiFC) and demonstrated their capabilities in quantifying and sorting cells based on their epigenetic modification contents. The sorted cells are viable and exhibit distinctive responses to chemo-therapy drugs. Notably, subpopulations of MCF7 cells with higher H3K9me3 levels are more likely to develop resistance to Doxorubicin. Subpopulations with higher 5mC levels, on the other hand, tend to be more responsive. Overall, we report for the first time, the application of novel split probes in flow cytometry application and elucidated the potential role of 5mC and H3K9me3 in determining drug responses.


Assuntos
Metilação de DNA , Epigênese Genética , Doxorrubicina/farmacologia , Fluorescência
7.
Cell Biol Toxicol ; 37(3): 421-439, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-32737625

RESUMO

Atrazine (ATZ), a commonly used pesticide linked to endocrine disruption, cancer, and altered neurochemistry, frequently contaminates water sources at levels above the US Environmental Protection Agency's 3 parts per billion (ppb; µg/L) maximum contaminant level. Adult male zebrafish behavior, brain transcriptome, brain methylation status, and neuropathology were examined to test the hypothesis that embryonic ATZ exposure causes delayed neurotoxicity, according to the developmental origins of health and disease paradigm. Zebrafish (Danio rerio) embryos were exposed to 0 ppb, 0.3 ppb, 3 ppb, or 30 ppb ATZ during embryogenesis (1-72 h post fertilization (hpf)), then rinsed and raised to maturity. At 9 months post fertilization (mpf), males had decreased locomotor parameters during a battery of behavioral tests. Transcriptomic analysis identified altered gene expression in organismal development, cancer, and nervous and reproductive system development and function pathways and networks. The brain was evaluated histopathologically for morphometric differences, and decreased numbers of cells were identified in raphe populations. Global methylation levels were evaluated at 12 mpf, and the body length, body weight, and brain weight were measured at 14 mpf to evaluate effects of ATZ on mature brain size. No significant difference in genome methylation or brain size was observed. The results demonstrate that developmental exposure to ATZ does affect neurodevelopment and neural function in adult male zebrafish and raises concern for possible health effects in humans due to ATZ's environmental presence and persistence. Graphical abstract.


Assuntos
Atrazina/efeitos adversos , Encéfalo/efeitos dos fármacos , Praguicidas/efeitos adversos , Transcriptoma/genética , Animais , Encéfalo/patologia , Desenvolvimento Embrionário/efeitos dos fármacos , Disruptores Endócrinos/efeitos adversos , Epigênese Genética/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Larva/efeitos dos fármacos , Larva/genética , Larva/crescimento & desenvolvimento , Transcriptoma/efeitos dos fármacos , Poluentes Químicos da Água/efeitos adversos , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento
8.
Biochim Biophys Acta ; 1839(11): 1323-9, 2014 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-25263161

RESUMO

BACKGROUND: Hydroxymethylation of DNA at the C5 position of cytosine (5hmC) is recognized as an important epigenetic mark. The molecular role of 5hmC in gene regulation, however, is not well understood. METHODS: We studied the effects of 5-hydroxymethylation (5hmC) on nucleosome properties in vitro using a combination of biochemical and fluorescence assays. Competitive reconstitution was used to evaluate the effect of 5hmC on nucleosome formation. The effects of 5hmC on nucleosome compactness and stability were characterized using FRET assays. These findings have also been compared with another important epigenetic mark, the cytosine methylation (5mC) of DNA. RESULTS: We observed that hydroxymethylation increases the binding affinity of DNA for the histone octamer. The formed nucleosome exhibits slightly different conformations based on the sequence and epigenetic context of DNA. DNA hydroxymethylation decreases the stability of formed nucleosomes in salt-induced dissociation processes. CONCLUSION: DNA containing 5hmC is more likely to be incorporated into nucleosomes. Once formed, the 5hmC nucleosomes might be in an open and transcriptionally active state due to the weakened interaction of hydroxymethylated DNA with the H2A-H2B dimers. GENERAL SIGNIFICANCE: Our results reveal the effect of 5hmC on regulating nucleosome compactness and stability in vitro.


Assuntos
Metilação de DNA , Conformação de Ácido Nucleico , Nucleossomos/química , Nucleossomos/metabolismo , Cromatina/química , Cromatina/metabolismo , DNA/metabolismo , Empacotamento do DNA , Histonas/química , Histonas/metabolismo , Humanos , Técnicas In Vitro , Ligação Proteica , Multimerização Proteica , Estabilidade Proteica
9.
Biopolymers ; 103(1): 33-40, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25196374

RESUMO

Chromatin structure and the transcriptional state of a gene can be modulated by modifications made on H3 and H4 tails of histones. Elucidating the internucleosomal interactions of these tails is vital to understanding epigenetic regulation. Differentiation between cis (intra-nucleosomal) and trans (inter-nucleosomal) interactions is often difficult with conventional techniques since H3 and H4 tails are flexible. The distinction, however, is important because these interactions model short- and long-range chromatin interactions respectively and have different bearings in biological processes. Combining FCS and PCH analysis, we can decouple the contribution of histone tails to cis and trans effects. A Mg(2+) gradient was employed to facilitate compaction and oligomerization of tetranucleosomes with H3 and/or H4 tail truncations. H3 tails were found to play a multifunctional role and exhibit the ability to partake in both attractive cis and trans interactions simultaneously. H4 tails partake in attractive cis and repulsive trans interactions at low [Mg(2+)]. These interactions are diminished at higher [Mg(2+)]. Simultaneous H3 and H4 tail truncation inhibited array oligomerization but maintained local array compaction at relatively high [Mg(2+)]. The established experimental approach can be extended to study the detailed molecular interactions mediated by epigenetic modification of flexible histone tails.


Assuntos
Nucleossomos/química , Nucleossomos/metabolismo , Histonas/química , Histonas/metabolismo , Conformação de Ácido Nucleico , Ligação Proteica
10.
Biophys J ; 107(7): 1629-36, 2014 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-25296315

RESUMO

DNA CpG methylation has been associated with chromatin compaction and gene silencing. Whether DNA methylation directly contributes to chromatin compaction remains an open question. In this study, we used fluorescence fluctuation spectroscopy (FFS) to evaluate the compaction and aggregation of tetra-nucleosomes containing specific CpG patterns and methylation levels. The compactness of both unmethylated and methylated tetra-nucleosomes is dependent on DNA sequences. Specifically, methylation of the CpG sites located in the central dyad and the major grooves of DNA seem to have opposite effects on modulating the compactness of tetra-nucleosomes. The interactions among tetra-nucleosomes, however, seem to be enhanced because of DNA methylation independent of sequence contexts. Our finding can shed light on understanding the role of DNA methylation in determining nucleosome positioning pattern and chromatin compactness.


Assuntos
Metilação de DNA , Nucleossomos/química , Nucleossomos/genética , Agregados Proteicos/efeitos dos fármacos , Animais , Sequência de Bases , Ilhas de CpG/genética , Metilação de DNA/efeitos dos fármacos , Regulação da Expressão Gênica , Magnésio/farmacologia , Modelos Moleculares , Conformação de Ácido Nucleico , Nucleossomos/efeitos dos fármacos , Conformação Proteica , Espectrometria de Fluorescência
11.
Biopolymers ; 101(5): 517-24, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24122444

RESUMO

In eukaryotic cells, DNA has to bend significantly to pack inside the nucleus. Physical properties of DNA such as bending flexibility and curvature are expected to affect DNA packaging and partially determine the nucleosome positioning patterns inside a cell. DNA CpG methylation, the most common epigenetic modification found in DNA, is known to affect the physical properties of DNA. However, its detailed role in nucleosome formation is less well-established. In this study, we evaluated the effect of defined CpG patterns (unmethylated and methylated) on DNA structure and their respective nucleosome-forming ability. Our results suggest that the addition of CpG dinucleotides, either as a (CG)n stretch or (CGX8 )n repeats at 10 bp intervals, lead to reduced hydrodynamic radius and decreased nucleosome-forming ability of DNA. This effect is more predominant for a DNA stretch ((CG)5) located in the middle of a DNA fragment. Methylation of CpG sites, surprisingly, seems to reduce the difference in DNA structure and nucleosome-forming ability among DNA constructs with different CpG patterns. Our results suggest that unmethylated and methylated CpG patterns can play very different roles in regulating the physical properties of DNA. CpG methylation seems to reduce the DNA conformational variations affiliated with defined CpG patterns. Our results can have significant bearings in understanding the nucleosome positioning pattern in living organisms modulated by DNA sequences and epigenetic features.


Assuntos
Metilação de DNA , DNA/química , Oligodesoxirribonucleotídeos/metabolismo , Eletroforese em Gel de Poliacrilamida , Modelos Moleculares , Nucleossomos/metabolismo
12.
Biotechnol Bioeng ; 111(4): 639-53, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24284881

RESUMO

Biodiesel is an environment-friendly and renewable fuel produced by transesterification of various feedstocks. Although the lipase-catalyzed biodiesel production has many advantages over the conventional alkali catalyzed process, its industrial applications have been limited by high-cost and low-stability of lipase enzymes. This review provides a general overview of the recent advances in lipase engineering, including both protein modification and production. Recent advances in biotechnology such as in protein engineering, recombinant methods and metabolic engineering have been employed but are yet to impact lipase engineering for cost-effective production of biodiesel. A summary of the current challenges and perspectives for potential solutions are also provided.


Assuntos
Biocombustíveis , Biotecnologia , Enzimas Imobilizadas , Lipase , Engenharia de Proteínas , Proteínas de Bactérias , Estabilidade Enzimática , Esterificação , Proteínas Fúngicas , Engenharia Metabólica
13.
Sci Total Environ ; 908: 168307, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37949145

RESUMO

Atrazine (ATZ) is one of the most used herbicides in the US and a known endocrine disruptor. ATZ is frequently detected in drinking water, especially in Midwestern regions of the United States, exceeding the EPA regulation of maximum contamination level (MCL) of 3 ppb. Epidemiology studies have suggested an association between ATZ exposure and neurodegeneration. Less, however, is known about the neurotoxic mechanism of ATZ, particularly for exposures at a developmental stage. Here, we exposed floor plate progenitors (FPPs) derived from human induced pluripotent stem cells (hiPSCs) to low concentrations of ATZ at 0.3 and 3 ppb for two days followed by differentiation into dopaminergic (DA) neurons in ATZ-free medium. We then examined the morphology, activity, pathological protein aggregation, and transcriptomic changes of differentiated DA neurons. We observed significant decrease in the complexity of neurite network, increase of neuronal activity, and elevated tau- and α-synuclein (aSyn) pathologies after ATZ exposure. The ATZ-induced neuronal changes observed here align with pathological characteristics in Parkinson's disease (PD). Transcriptomic analysis further corroborates our findings; and collectively provides a strong evidence base that low-concentration ATZ exposure during development can elicit increased risk of neurodegeneration.


Assuntos
Atrazina , Herbicidas , Células-Tronco Pluripotentes Induzidas , Doença de Parkinson , Humanos , Atrazina/toxicidade , Neurônios Dopaminérgicos , Herbicidas/toxicidade
14.
Biophys J ; 104(5): 1081-8, 2013 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-23473491

RESUMO

Förster resonance energy transfer was used to monitor the dynamic conformations of mononucleosomes under different chromatin folding conditions to elucidate the role of the flexible N-terminal regions of H3 and H4 histones. The H3 tail was shown to partake in intranucleosomal interactions by restricting the DNA breathing motion and compacting the nucleosome. The H3 tail effects were mostly independent of the ionic strength and valency of the ions. The H4 tail was shown to not greatly affect the nucleosome conformation, but did slightly influence the relative population of the preferred conformation. The role of the H4 tail varied depending on the valency and ionic strength, suggesting that electrostatic forces play a primary role in H4 tail interactions. Interestingly, despite the H4 tail's lack of influence, when H3 and H4 tails were simultaneously clipped, a more dramatic effect was seen than when only H3 or H4 tails were clipped. The combinatorial effect of H3 and H4 tail truncation suggests a potential mechanism by which various combinations of histone tail modifications can be used to control accessibility of DNA-binding proteins to nucleosomal DNA.


Assuntos
Histonas/química , Nucleossomos/química , Deleção de Sequência , Sequência de Aminoácidos , Animais , DNA/química , Transferência Ressonante de Energia de Fluorescência , Concentração Osmolar , Ligação Proteica , Estrutura Terciária de Proteína , Proteínas Recombinantes/química , Eletricidade Estática , Xenopus laevis
15.
Biophys J ; 105(1): 194-9, 2013 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-23823239

RESUMO

The nucleosome is the first level of genome organization and regulation in eukaryotes where negatively charged DNA is wrapped around largely positively charged histone proteins. Interaction between nucleosomes is dominated by electrostatics at long range and guided by specific contacts at short range, particularly involving their flexible histone tails. We have thus quantified how internucleosome interactions are modulated by salts (KCl, MgCl2) and histone tail deletions (H3, H4 N-terminal), using small-angle x-ray scattering and theoretical modeling. We found that measured effective charges at low salts are ∼1/5th of the theoretically predicted renormalized charges and that H4 tail deletion suppresses the attraction at high salts to a larger extent than H3 tail deletion.


Assuntos
Histonas/química , Histonas/metabolismo , Nucleossomos/metabolismo , Animais , Galinhas , Cloreto de Magnésio/farmacologia , Cloreto de Potássio/farmacologia , Ligação Proteica/efeitos dos fármacos , Espalhamento a Baixo Ângulo , Eletricidade Estática , Difração de Raios X
16.
Biomedicines ; 11(4)2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37189648

RESUMO

Clinical and animal studies have shown that acupuncture may benefit controlling neuropathic pain. However, the underlying molecular mechanisms are poorly understood. In a well-established mouse unilateral tibial nerve injury (TNI) model, we confirmed the efficacy of electroacupuncture (EA) in reducing mechanical allodynia and measured methylation and hydroxy-methylation levels in the primary somatosensory cortex (S1) and anterior cingulate cortex (ACC), two cortical regions critically involved in pain processing. TNI resulted in increased DNA methylation of both the contra- and ipsilateral S1, while EA only reduced contralateral S1 methylation. RNA sequencing of the S1 and ACC identified differentially expressed genes related to energy metabolism, inflammation, synapse function, and neural plasticity and repair. One week of daily EA decreased or increased the majority of up- or downregulated genes, respectively, in both cortical regions. Validations of two greatly regulated genes with immunofluorescent staining revealed an increased expression of gephyrin in the ipsilateral S1 after TNI was decreased by EA; while TNI-induced increases in Tomm20, a biomarker of mitochondria, in the contralateral ACC were further enhanced after EA. We concluded that neuropathic pain is associated with differential epigenetic regulations of gene expression in the ACC and S1 and that the analgesic effect of EA may involve regulating cortical gene expression.

17.
Chemosphere ; 332: 138900, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37172627

RESUMO

GenX, also known as hexafluoropropylene oxide dimer acid (HFPO-DA) was introduced as a safer alternative to perfluorooctanoic acid (PFOA) in 2009. After nearly two decades of applications there are increasing safety concerns about GenX due to its association with various organ damages. Few studies, however, have systematically assessed the molecular neurotoxicity of low-dose GenX exposure. Here, we evaluated the effects of pre-differentiation exposure of GenX on dopaminergic (DA) -like neurons using SH-SY5Y cell line; and assessed changes in epigenome, mitochondrion, and neuronal characteristics. Low dose GenX exposure at 0.4 and 4 µg/L prior to differentiation induced persistent changes in nuclear morphology and chromatin arrangements, manifested specifically in the facultative repressive marker H3K27me3. We also observed impaired neuronal network, increased calcium activity along with alterations in Tyrosine hydroxylase (TH) and α-Synuclein (αSyn) after prior exposure to GenX. Collectively, our results identified neurotoxicity of low-dose GenX exposure in human DA-like neurons following a developmental exposure scheme. The observed changes in neuronal characteristics suggest GenX as a potential neurotoxin and risk factor for Parkinson's disease.


Assuntos
Fluorocarbonos , Neuroblastoma , Doença de Parkinson , Humanos , Fluorocarbonos/metabolismo , Neurônios , Linhagem Celular , Diferenciação Celular , Neurônios Dopaminérgicos/metabolismo
18.
Mol Neurobiol ; 60(5): 2937-2953, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36750527

RESUMO

Spinal cord injury is a severely debilitating condition affecting a significant population in the USA. Spinal cord injury patients often have increased risk of developing persistent neuropathic pain and other neurodegenerative conditions beyond the primary lesion center later in their life. The molecular mechanism conferring to the "latent" damages at distal tissues, however, remains elusive. Here, we studied molecular changes conferring abnormal functionality at distal spinal cord (T12) beyond the lesion center (T10) by combining next-generation sequencing (RNA- and bisulfite sequencing), super-resolution microscopy, and immunofluorescence staining at 7 days post injury. We observed significant transcriptomic changes primarily enriched in neuroinflammation and synaptogenesis associated pathways. Transcription factors (TFs) that regulate neurogenesis and neuron plasticity, including Egr1, Klf4, and Myc, are significantly upregulated. Along with global changes in chromatin arrangements and DNA methylation, including 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC), bisulfite sequencing further reveals the involvement of DNA methylation changes in regulating cytokine, growth factor, and ion channel expression. Collectively, our results pave the way towards understanding transcriptomic and epigenomic mechanism in conferring long-term disease risks at distal tissues away from the primary lesion center and shed light on potential molecular targets that govern the regulatory mechanism at distal spinal cord tissues.


Assuntos
Contusões , Traumatismos da Medula Espinal , Ratos , Animais , Epigênese Genética , Transcriptoma/genética , Epigenômica/métodos , Traumatismos da Medula Espinal/genética , Traumatismos da Medula Espinal/patologia , Metilação de DNA/genética , Medula Espinal/patologia
19.
Elife ; 122023 09 19.
Artigo em Inglês | MEDLINE | ID: mdl-37724949

RESUMO

Cell spreading and migration play central roles in many physiological and pathophysiological processes. We have previously shown that MFN2 regulates the migration of human neutrophil-like cells via suppressing Rac activation. Here, we show that in mouse embryonic fibroblasts, MFN2 suppresses RhoA activation and supports cell polarization. After initial spreading, the wild-type cells polarize and migrate, whereas the Mfn2-/- cells maintain a circular shape. Increased cytosolic Ca2+ resulting from the loss of Mfn2 is directly responsible for this phenotype, which can be rescued by expressing an artificial tether to bring mitochondria and endoplasmic reticulum to close vicinity. Elevated cytosolic Ca2+ activates Ca2+/calmodulin-dependent protein kinase II, RhoA, and myosin light-chain kinase, causing an overactivation of nonmuscle myosin II, leading to a formation of a prominent F-actin ring at the cell periphery and increased cell contractility. The peripheral actin band alters cell physics and is dependent on substrate rigidity. Our results provide a novel molecular basis to understand how MFN2 regulates distinct signaling pathways in different cells and tissue environments, which is instrumental in understanding and treating MFN2-related diseases.


Assuntos
Actinas , Fibroblastos , Animais , Humanos , Camundongos , Actinas/metabolismo , Fibroblastos/metabolismo , Transdução de Sinais , Retículo Endoplasmático/metabolismo , Miosina Tipo II/genética , Miosina Tipo II/metabolismo
20.
Res Sq ; 2023 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-37841865

RESUMO

Autism spectrum disorder (ASD) is a major neurodevelopmental disorder affecting 1 in 36 children in the United States. While neurons have been the focus to understand ASD, an altered neuro-immune response in the brain may be closely associated with ASD, and a neuro-immune interaction could play a role in the disease progression. As the resident immune cells of the brain, microglia regulate brain development and homeostasis via core functions including phagocytosis of synapses. While ASD has been traditionally considered a polygenic disorder, recent large-scale human genetic studies have identified SCN2A deficiency as a leading monogenic cause of ASD and intellectual disability. We generated a Scn2a-deficient mouse model, which displays major behavioral and neuronal phenotypes. However, the role of microglia in this disease model is unknown. Here, we reported that Scn2a-deficient mice have impaired learning and memory, accompanied by reduced synaptic transmission and lower spine density in neurons of the hippocampus. Microglia in Scn2a-deficient mice are partially activated, exerting excessive phagocytic pruning of post-synapses related to the complement C3 cascades during selective developmental stages. The ablation of microglia using PLX3397 partially restores synaptic transmission and spine density. To extend our findings from rodents to human cells, we established a microglial-incorporated human cerebral organoid model carrying an SCN2A protein-truncating mutation identified in children with ASD. We found that human microglia display increased elimination of post-synapse in cerebral organoids carrying the SCN2A mutation. Our study establishes a key role of microglia in multi-species autism-associated models of SCN2A deficiency from mouse to human cells.

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