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1.
Proc Natl Acad Sci U S A ; 118(45)2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34740969

RESUMO

Myelin, the structure that surrounds and insulates neuronal axons, is an important component of the central nervous system. The visualization of the myelinated fibers in brain tissues can largely facilitate the diagnosis of myelin-related diseases and understand how the brain functions. However, the most widely used fluorescent probes for myelin visualization, such as Vybrant DiD and FluoroMyelin, have strong background staining, low-staining contrast, and low brightness. These drawbacks may originate from their self-quenching properties and greatly limit their applications in three-dimensional (3D) imaging and myelin tracing. Chemical probes for the fluorescence imaging of myelin in 3D, especially in optically cleared tissue, are highly desirable but rarely reported. We herein developed a near-infrared aggregation-induced emission (AIE)-active probe, PM-ML, for high-performance myelin imaging. PM-ML is plasma membrane targeting with good photostability. It could specifically label myelinated fibers in teased sciatic nerves and mouse brain tissues with a high-signal-to-background ratio. PM-ML could be used for 3D visualization of myelin sheaths, myelinated fibers, and fascicles with high-penetration depth. The staining is compatible with different brain tissue-clearing methods, such as ClearT and ClearT2 The utility of PM-ML staining in demyelinating disease studies was demonstrated using the mouse model of multiple sclerosis. Together, this work provides an important tool for high-quality myelin visualization across scales, which may greatly contribute to the study of myelin-related diseases.

2.
ACS Chem Neurosci ; 12(22): 4249-4256, 2021 11 17.
Artigo em Inglês | MEDLINE | ID: mdl-34738783

RESUMO

Alzheimer's disease (AD), the most common neurodegenerative disease, has limited treatment options. As such, extensive studies have been conducted to identify novel therapeutic approaches. We previously reported that rhynchophylline (Rhy), a small molecule EphA4 inhibitor, rescues impaired hippocampal synaptic plasticity and cognitive dysfunctions in APP/PS1 mice, an AD transgenic mouse model. To assess whether Rhy can be developed as an alternative treatment for AD, it is important to examine its pharmacokinetics and effects on other disease-associated pathologies. Here, we show that Rhy ameliorates amyloid plaque burden and reduces inflammation in APP/PS1 mice. Transcriptome analysis revealed that Rhy regulates various molecular pathways in APP/PS1 mouse brains associated with amyloid metabolism and inflammation, specifically the ubiquitin proteasome system, angiogenesis, and microglial functional states. These results show that Rhy, which is blood-brain barrier permeable, is beneficial to amyloid pathology and regulates multiple molecular pathways.


Assuntos
Doença de Alzheimer , Doenças Neurodegenerativas , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides , Precursor de Proteína beta-Amiloide/genética , Animais , Modelos Animais de Doenças , Inflamação/tratamento farmacológico , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Oxindóis , Placa Amiloide/tratamento farmacológico , Presenilina-1/genética
3.
Eur J Med Chem ; 226: 113827, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34530383

RESUMO

Cholinergic neurons are ubiquitous and involved in various higher brain functions including learning and memory. Patients with Alzheimer's disease exhibit significant dysfunction and loss of cholinergic neurons. Meanwhile, such cholinergic deficits can be potentially relieved pharmacologically by increasing acetylcholine. Acetylcholinesterase (AChE) inhibitors have been used to improve cholinergic transmission in the brain for two decades and have proven effective for alleviating symptoms in the early stages of Alzheimer's disease. Therefore, the search for AChE inhibitors for drug development is ongoing. The enzymatic pocket of AChE has long been the target of several drug designs over the last two decades. The peripheral and catalytic sites of AChE are simultaneously bound by several dimeric molecules, enabling more-efficient inhibition. Here, we used 6-chlorotacrine and the tetrahydroquinolone moiety of huperzine A to design and synthesize a series of heterodimers that inhibit AChE at nanomolar potency. Specifically, compound 7b inhibits AChE with an IC50 < 1 nM and spares butyrylcholinesterase. Administration of 7b to mouse brain slices restores synaptic activity impaired by pirenzepine, a muscarinic M1-selective antagonist. Moreover, oral administration of 7b to C57BL/6 mice enhances hippocampal long-term potentiation in a dose-dependent manner and is detectable in the brain tissue. All these data supported that 7b is a potential cognitive enhancer and is worth for further exploration.

4.
Biomolecules ; 11(8)2021 08 16.
Artigo em Inglês | MEDLINE | ID: mdl-34439882

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that manifests as cognitive deficits and memory decline, especially in old age. Several biomarkers have been developed to monitor AD progression. Given that the retina and brain share some similarities including features related to anatomical composition and neurological functions, the retina is closely associated with the progression of AD. Herein, we review the evidence of retinal dysfunction in AD, particularly at the early stage, together with the underlying molecular mechanisms. Furthermore, we compared the retinal pathologies of AD and other ophthalmological diseases and summarized potential retinal biomarkers measurable by existing technologies for detecting AD, providing insights for the future development of diagnostic tools.


Assuntos
Doença de Alzheimer , Biomarcadores/metabolismo , Degeneração Retiniana/metabolismo , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Animais , Humanos
5.
Nat Biomed Eng ; 2021 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-34312508

RESUMO

The pathology of familial Alzheimer's disease, which is caused by dominant mutations in the gene that encodes amyloid-beta precursor protein (APP) and in those that encode presenilin 1 and presenilin 2, is characterized by extracellular amyloid plaques and intracellular neurofibrillary tangles in multiple brain regions. Here we show that the brain-wide selective disruption of a mutated APP allele in transgenic mouse models carrying the human APP Swedish mutation alleviates amyloid-beta-associated pathologies for at least six months after a single intrahippocampal administration of an adeno-associated virus that encodes both Cas9 and a single-guide RNA that targets the mutation. We also show that the deposition of amyloid-beta, as well as microgliosis, neurite dystrophy and the impairment of cognitive performance, can all be ameliorated when the CRISPR-Cas9 construct is delivered intravenously via a modified adeno-associated virus that can cross the blood-brain barrier. Brain-wide disease-modifying genome editing could represent a viable strategy for the treatment of familial Alzheimer's disease and other monogenic diseases that affect multiple brain regions.

6.
DNA Cell Biol ; 40(9): 1125-1130, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34297618

RESUMO

In response to neuronal activity changes, the adult hippocampal circuits undergo continuous synaptic remodeling, which is essential for information processing, learning, and memory encoding. Glial cells, including astrocytes and microglia, actively regulate hippocampal synaptic plasticity by coordinating the neuronal activity-induced synaptic changes at the circuit level. Emerging evidence suggests that the crosstalk between neurons and glia in the adult hippocampus is region specific and that the mechanisms controlling this process are critically dependent on secreted factors. Interleukin-33 (IL-33), a cytokine of the IL-1 family, is a key factor that modulates such glia-driven neuromodulations in two distinct hippocampal circuits. The activation of IL-33 and its receptor complex is important for maintaining the excitatory synaptic activity in the cornu ammonis 1 subregion and the remodeling of dentate gyrus synapses through activity-dependent astrocyte-synapse and microglia-synapse interactions, respectively. Meanwhile, the dysregulation of this signaling is implicated in multiple neurological disorders, especially Alzheimer's disease. Further investigations of how IL-33/ST2 signaling is regulated in a region-specific manner as well as its diverse functions in glia-synapse communications in the adult hippocampal circuitry will provide insights into the nature of hippocampal synaptic plasticity and homeostasis in health and disease.


Assuntos
Doença de Alzheimer/metabolismo , Astrócitos/metabolismo , Interleucina-33/fisiologia , Microglia/metabolismo , Plasticidade Neuronal , Adulto , Animais , Astrócitos/citologia , Astrócitos/patologia , Hipocampo/metabolismo , Humanos , Camundongos , Microglia/citologia , Microglia/patologia , Sinapses/metabolismo
7.
J Exp Med ; 218(8)2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34156424

RESUMO

Biochemical, pathogenic, and human genetic data confirm that GSAP (γ-secretase activating protein), a selective γ-secretase modulatory protein, plays important roles in Alzheimer's disease (AD) and Down's syndrome. However, the molecular mechanism(s) underlying GSAP-dependent pathogenesis remains largely elusive. Here, through unbiased proteomics and single-nuclei RNAseq, we identified that GSAP regulates multiple biological pathways, including protein phosphorylation, trafficking, lipid metabolism, and mitochondrial function. We demonstrated that GSAP physically interacts with the Fe65-APP complex to regulate APP trafficking/partitioning. GSAP is enriched in the mitochondria-associated membrane (MAM) and regulates lipid homeostasis through the amyloidogenic processing of APP. GSAP deletion generates a lipid environment unfavorable for AD pathogenesis, leading to improved mitochondrial function and the rescue of cognitive deficits in an AD mouse model. Finally, we identified a novel GSAP single-nucleotide polymorphism that regulates its brain transcript level and is associated with an increased AD risk. Together, our findings indicate that GSAP impairs mitochondrial function through its MAM localization and that lowering GSAP expression reduces pathological effects associated with AD.


Assuntos
Doença de Alzheimer/patologia , Homeostase , Metabolismo dos Lipídeos , Mitocôndrias/metabolismo , Proteínas/metabolismo , Envelhecimento/patologia , Doença de Alzheimer/genética , Precursor de Proteína beta-Amiloide/metabolismo , Animais , Sequência de Bases , Modelos Animais de Doenças , Hipocampo/metabolismo , Humanos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Membranas Mitocondriais/metabolismo , Modelos Biológicos , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Proteínas Nucleares/metabolismo , Teste de Campo Aberto , Fosforilação , Ligação Proteica , Transporte Proteico , Proteínas/genética , Transcrição Genética
8.
Alzheimers Dement ; 2021 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-34032364

RESUMO

INTRODUCTION: Blood proteins are emerging as candidate biomarkers for Alzheimer's disease (AD). We systematically profiled the plasma proteome to identify novel AD blood biomarkers and develop a high-performance, blood-based test for AD. METHODS: We quantified 1160 plasma proteins in a Hong Kong Chinese cohort by high-throughput proximity extension assay and validated the results in an independent cohort. In subgroup analyses, plasma biomarkers for amyloid, tau, phosphorylated tau, and neurodegeneration were used as endophenotypes of AD. RESULTS: We identified 429 proteins that were dysregulated in AD plasma. We selected 19 "hub proteins" representative of the AD plasma protein profile, which formed the basis of a scoring system that accurately classified clinical AD (area under the curve  = 0.9690-0.9816) and associated endophenotypes. Moreover, specific hub proteins exhibit disease stage-dependent dysregulation, which can delineate AD stages. DISCUSSION: This study comprehensively profiled the AD plasma proteome and serves as a foundation for a high-performance, blood-based test for clinical AD screening and staging.

9.
Cell Mol Life Sci ; 78(10): 4703-4712, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33847763

RESUMO

Genetic analyses have revealed the pivotal contribution of microglial dysfunctions to the pathogenesis of Alzheimer's disease (AD). Along AD progression, the accumulation of danger-associated molecular patterns (DAMPs) including beta-amyloid and hyperphosphorylated tau continuously stimulates microglia, which results in their chronic activation. Chronically activated microglia secrete excessive pro-inflammatory cytokines, which further regulate microglial responses towards DAMPs. This has spurred longstanding interest in targeting cytokine-induced microglial responses for AD therapeutic development. However, the cytokine-induced microglial state transition is not comprehensively understood. Cytokines are assumed to induce microglial state transition from a resting state to an activated state. However, recent evidence indicate that this microglial state transition involves multiple sequential functional states. Moreover, the mechanisms by which different functional states within the cytokine-induced microglial state transition regulate AD pathology remain unclear. In this review, we summarize how different cytokine signaling pathways, including those of IL-33 (interleukin-33), NLRP3 inflammasome-IL-1ß, IL-10, and IL-12/IL-23, regulate microglial functions in AD. Furthermore, we discuss how the modulation of these cytokine signaling pathways can result in beneficial outcomes in AD. Finally, we describe a stepwise functional state transition of microglia induced by cytokine signaling that can provide insights into the molecular basis of the beneficial effects of cytokine modulation in AD and potentially aid therapeutic development.


Assuntos
Doença de Alzheimer/metabolismo , Citocinas/metabolismo , Microglia/metabolismo , Transdução de Sinais/fisiologia , Peptídeos beta-Amiloides/metabolismo , Animais , Humanos , Inflamassomos/metabolismo
10.
FEBS J ; 2021 Apr 17.
Artigo em Inglês | MEDLINE | ID: mdl-33864430

RESUMO

In the adult hippocampus, synaptic plasticity is important for information processing, learning, and memory encoding. Astrocytes, the most common glial cells, play a pivotal role in the regulation of hippocampal synaptic plasticity. While astrocytes were initially described as a homogenous cell population, emerging evidence indicates that in the adult hippocampus, astrocytes are highly heterogeneous and can differentially respond to changes in neuronal activity in a subregion-dependent manner to actively modulate synaptic plasticity. In this review, we summarize how local neuronal activity changes regulate the interactions between astrocytes and synapses, either by modulating the secretion of gliotransmitters and synaptogenic proteins or via contact-mediated signaling pathways. In turn, these specific responses induced in astrocytes mediate the interactions between astrocytes and neurons, thus shaping synaptic communication in the adult hippocampus. Importantly, the activation of astrocytic signaling is required for memory performance including memory acquisition and recall. Meanwhile, the dysregulation of this signaling can cause hippocampal circuit dysfunction in pathological conditions, resulting in cognitive impairment and neurodegeneration. Indeed, reactive astrocytes, which have dysregulated signaling associated with memory, are induced in the brains of patients with Alzheimer's disease (AD) and transgenic mouse model of AD. Emerging technologies that can precisely manipulate and monitor astrocytic signaling in vivo enable the examination of the specific actions of astrocytes in response to neuronal activity changes as well as how they modulate synaptic connections and circuit activity. Such findings will clarify the roles of astrocytes in hippocampal synaptic plasticity and memory in health and disease.

11.
Front Neurosci ; 15: 650220, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33854414

RESUMO

The high prevalence of Alzheimer's disease (AD) among the elderly population and its lack of effective treatments make this disease a critical threat to human health. Recent epidemiological and genetics studies have revealed the polygenic nature of the disease, which is possibly explainable by a polygenic score model that considers multiple genetic risks. Here, we systemically review the rationale and methods used to construct polygenic score models for studying AD. We also discuss the associations of polygenic risk scores (PRSs) with clinical outcomes, brain imaging findings, and biochemical biomarkers from both the brain and peripheral system. Finally, we discuss the possibility of incorporating polygenic score models into research and clinical practice along with potential challenges.

12.
Curr Opin Neurobiol ; 69: 58-67, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-33647674

RESUMO

APOE (apolipoprotein E) is a key regulator of lipid metabolism and a leading genetic risk factor for Alzheimer's disease. While APOE participates in multiple biological pathways, its roles in diseases are largely due to the mutant protein encoded by APOE-ε4. However, emerging evidence suggests that some noncoding Alzheimer's disease risk variants residing in APOE and its nearby regions exert APOE-ε4-independent risks and modify APOE gene expression. Moreover, intervention strategies targeting APOE are being explored. In this review, we summarize the literature on the genetic risks and roles of APOE in biological systems. Moreover, we propose an integrative approach to evaluate disease risk and tailor interventions to aid research on APOE-associated diseases.


Assuntos
Doença de Alzheimer , Apolipoproteínas E/metabolismo , Doenças Neurodegenerativas , Doença de Alzheimer/genética , Apolipoproteínas E/genética , Humanos , Doenças Neurodegenerativas/genética , Transdução de Sinais/genética
13.
Commun Biol ; 4(1): 195, 2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33580208

RESUMO

The dysregulation of gene dosage due to duplication or haploinsufficiency is a major cause of autosomal dominant diseases such as Alzheimer's disease. However, there is currently no rapid and efficient method for manipulating gene dosage in a human model system such as human induced pluripotent stem cells (iPSCs). Here, we demonstrate a simple and precise method to simultaneously generate iPSC lines with different gene dosages using paired Cas9 nickases. We first generate a Cas9 nickase variant with broader protospacer-adjacent motif specificity to expand the targetability of double-nicking-mediated genome editing. As a proof-of-concept study, we examine the gene dosage effects on an Alzheimer's disease patient-derived iPSC line that carries three copies of APP (amyloid precursor protein). This method enables the rapid and simultaneous generation of iPSC lines with monoallelic, biallelic, or triallelic knockout of APP. The cortical neurons generated from isogenically corrected iPSCs exhibit gene dosage-dependent correction of disease-associated phenotypes of amyloid-beta secretion and Tau hyperphosphorylation. Thus, the rapid generation of iPSCs with different gene dosages using our method described herein can be a useful model system for investigating disease mechanisms and therapeutic development.


Assuntos
Proteína 9 Associada à CRISPR/genética , Sistemas CRISPR-Cas , Repetições Palindrômicas Curtas Agrupadas e Regularmente Espaçadas , Variações do Número de Cópias de DNA , Dosagem de Genes , Edição de Genes , Células-Tronco Pluripotentes Induzidas/metabolismo , Neurônios/metabolismo , Peptídeos beta-Amiloides/metabolismo , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/metabolismo , Apoptose , Proteína 9 Associada à CRISPR/metabolismo , Linhagem Celular , Regulação da Expressão Gênica , Humanos , Células-Tronco Pluripotentes Induzidas/patologia , Neurogênese , Neurônios/patologia , Fosforilação , Estudo de Prova de Conceito , Proteínas tau/metabolismo
14.
Sci Rep ; 11(1): 4359, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33623128

RESUMO

Alzheimer's disease (AD) is a devastating neurodegenerative disorder with no disease-modifying treatment. AD progression is characterized by cognitive decline, neuroinflammation, and accumulation of amyloid-beta (Aß) and neurofibrillary tangles in the brain, leading to neuronal and glial dysfunctions. Neuropeptides govern diverse pathophysiological processes and represent key players in AD pathogenesis, regulating synaptic plasticity, glial cell functions and amyloid pathology. Activation of the pro-opiomelanocortin (POMC)-derived neuropeptide and its receptor from the melanocortin receptor (MCR) family have previously been shown to rescue the impairment in hippocampus-dependent synaptic plasticity in the APP/PS1 mouse model of AD. However, the functional roles of MCR signaling in AD conditions, particularly in glial functions, are largely unknown. In this study, we investigated the potential benefits of MCR activation in AD. In APP/PS1 transgenic mice, we demonstrate that MCR activation mediated by the central administration of its agonist D-Tyr MTII substantially reduces Aß accumulation, while alleviating global inflammation and astrocytic activation, particularly in the hippocampus. MCR activation prominently reduces the A1 subtype of reactive astrocytes, which is considered a key source of astrocytic neurotoxicity in AD. Concordantly, MCR activation suppresses microglial activation, while enhancing their association with amyloid plaques. The blunted activation of microglia may contribute to the reduction in the neurotoxic phenotypes of astrocytes. Importantly, transcriptome analysis reveals that MCR activation restores the impaired homeostatic processes and microglial reactivity in the hippocampus in APP/PS1 mice. Collectively, our findings demonstrate the potential of MCR signaling as therapeutic target for AD.


Assuntos
Doença de Alzheimer/tratamento farmacológico , Astrócitos/metabolismo , Receptores de Melanocortina/agonistas , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/efeitos dos fármacos , Hipocampo/metabolismo , Hipocampo/patologia , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Fármacos Neuroprotetores/química , Fármacos Neuroprotetores/farmacologia , Fármacos Neuroprotetores/uso terapêutico , Peptídeos Cíclicos/química , Receptores de Melanocortina/metabolismo , Tirosina/análogos & derivados , alfa-MSH/análogos & derivados , alfa-MSH/química
15.
Proc Natl Acad Sci U S A ; 118(1)2021 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-33443211

RESUMO

Hippocampal synaptic plasticity is important for learning and memory formation. Homeostatic synaptic plasticity is a specific form of synaptic plasticity that is induced upon prolonged changes in neuronal activity to maintain network homeostasis. While astrocytes are important regulators of synaptic transmission and plasticity, it is largely unclear how they interact with neurons to regulate synaptic plasticity at the circuit level. Here, we show that neuronal activity blockade selectively increases the expression and secretion of IL-33 (interleukin-33) by astrocytes in the hippocampal cornu ammonis 1 (CA1) subregion. This IL-33 stimulates an increase in excitatory synapses and neurotransmission through the activation of neuronal IL-33 receptor complex and synaptic recruitment of the scaffold protein PSD-95. We found that acute administration of tetrodotoxin in hippocampal slices or inhibition of hippocampal CA1 excitatory neurons by optogenetic manipulation increases IL-33 expression in CA1 astrocytes. Furthermore, IL-33 administration in vivo promotes the formation of functional excitatory synapses in hippocampal CA1 neurons, whereas conditional knockout of IL-33 in CA1 astrocytes decreases the number of excitatory synapses therein. Importantly, blockade of IL-33 and its receptor signaling in vivo by intracerebroventricular administration of its decoy receptor inhibits homeostatic synaptic plasticity in CA1 pyramidal neurons and impairs spatial memory formation in mice. These results collectively reveal an important role of astrocytic IL-33 in mediating the negative-feedback signaling mechanism in homeostatic synaptic plasticity, providing insights into how astrocytes maintain hippocampal network homeostasis.


Assuntos
Astrócitos/metabolismo , Região CA1 Hipocampal/metabolismo , Interleucina-33/metabolismo , Plasticidade Neuronal , Transdução de Sinais/efeitos dos fármacos , Memória Espacial/efeitos dos fármacos , Animais , Astrócitos/efeitos dos fármacos , Proteína 4 Homóloga a Disks-Large/metabolismo , Técnicas de Inativação de Genes , Hipocampo/metabolismo , Homeostase , Interleucina-33/administração & dosagem , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Plasticidade Neuronal/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Ratos , Sinapses/efeitos dos fármacos , Sinapses/genética , Sinapses/metabolismo , Transmissão Sináptica/efeitos dos fármacos , Tetrodotoxina/farmacologia
16.
STAR Protoc ; 2(1): 100265, 2021 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-33490981

RESUMO

Alzheimer's disease is characterized by the deposition of extracellular amyloid-beta (Aß) plaques. While microglial phagocytosis is a major mechanism through which Aß is cleared, there is no method for quantitatively assessing Aß phagocytic capacity of microglia in vivo. Here, we present a flow cytometry-based method for investigating the Aß phagocytic capacity of microglia in vivo. This method enables the direct comparison of Aß phagocytic capacity between different microglial subpopulations as well as the direct isolation of Aß phagocytic microglia for downstream applications. For complete details on the use and execution of this protocol, please refer to Lau et al. (2020).

17.
Sci Rep ; 10(1): 18746, 2020 10 30.
Artigo em Inglês | MEDLINE | ID: mdl-33127972

RESUMO

Dendrites, branched structures extending from neuronal cell soma, are specialized for processing information from other neurons. The morphogenesis of dendritic structures is spatiotemporally regulated by well-orchestrated signaling cascades. Dysregulation of these processes impacts the wiring of neuronal circuit and efficacy of neurotransmission, which contribute to the pathogeneses of neurological disorders. While Cdk5 (cyclin-dependent kinase 5) plays a critical role in neuronal dendritic development, its underlying molecular control is not fully understood. In this study, we show that p39, one of the two neuronal Cdk5 activators, is a key regulator of dendritic morphogenesis. Pyramidal neurons deficient in p39 exhibit aberrant dendritic morphology characterized by shorter length and reduced arborization, which is comparable to dendrites in Cdk5-deficient neurons. RNA sequencing analysis shows that the adaptor protein, WDFY1 (WD repeat and FYVE domain-containing 1), acts downstream of Cdk5/p39 to regulate dendritic morphogenesis. While WDFY1 is elevated in p39-deficient neurons, suppressing its expression rescues the impaired dendritic arborization. Further phosphoproteomic analysis suggests that Cdk5/p39 mediates dendritic morphogenesis by modulating various downstream signaling pathways, including PI3K/Akt-, cAMP-, or small GTPase-mediated signaling transduction pathways, thereby regulating cytoskeletal organization, protein synthesis, and protein trafficking.


Assuntos
Quinase 5 Dependente de Ciclina/metabolismo , Proteínas do Citoesqueleto/metabolismo , Dendritos/metabolismo , Proteínas Ligadas a Lipídeos/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Western Blotting , Diferenciação Celular/genética , Diferenciação Celular/fisiologia , AMP Cíclico/metabolismo , Quinase 5 Dependente de Ciclina/genética , Proteínas do Citoesqueleto/genética , Células HEK293 , Humanos , Proteínas Ligadas a Lipídeos/genética , Espectrometria de Massas , Camundongos , Proteínas Monoméricas de Ligação ao GTP/genética , Proteínas Monoméricas de Ligação ao GTP/metabolismo , Morfogênese/genética , Morfogênese/fisiologia , Sistema Nervoso/citologia , Sistema Nervoso/metabolismo , Neurônios/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/genética , Transdução de Sinais/fisiologia , Transmissão Sináptica/genética , Transmissão Sináptica/fisiologia
18.
Sci Adv ; 6(40)2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32998883

RESUMO

Optical deep-brain imaging in vivo at high resolution has remained a great challenge over the decades. Two-photon endomicroscopy provides a minimally invasive approach to image buried brain structures, once it is integrated with a gradient refractive index (GRIN) lens embedded in the brain. However, its imaging resolution and field of view are compromised by the intrinsic aberrations of the GRIN lens. Here, we develop a two-photon endomicroscopy by adding adaptive optics based on direct wavefront sensing, which enables recovery of diffraction-limited resolution in deep-brain imaging. A new precompensation strategy plays a critical role to correct aberrations over large volumes and achieve rapid random-access multiplane imaging. We investigate the neuronal plasticity in the hippocampus, a critical deep brain structure, and reveal the relationship between the somatic and dendritic activity of pyramidal neurons.

19.
Proc Natl Acad Sci U S A ; 117(41): 25800-25809, 2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-32989152

RESUMO

Alzheimer's disease (AD) is the most common form of dementia but has no effective treatment. A comprehensive investigation of cell type-specific responses and cellular heterogeneity in AD is required to provide precise molecular and cellular targets for therapeutic development. Accordingly, we perform single-nucleus transcriptome analysis of 169,496 nuclei from the prefrontal cortical samples of AD patients and normal control (NC) subjects. Differential analysis shows that the cell type-specific transcriptomic changes in AD are associated with the disruption of biological processes including angiogenesis, immune activation, synaptic signaling, and myelination. Subcluster analysis reveals that compared to NC brains, AD brains contain fewer neuroprotective astrocytes and oligodendrocytes. Importantly, our findings show that a subpopulation of angiogenic endothelial cells is induced in the brain in patients with AD. These angiogenic endothelial cells exhibit increased expression of angiogenic growth factors and their receptors (i.e., EGFL7, FLT1, and VWF) and antigen-presentation machinery (i.e., B2M and HLA-E). This suggests that these endothelial cells contribute to angiogenesis and immune response in AD pathogenesis. Thus, our comprehensive molecular profiling of brain samples from patients with AD reveals previously unknown molecular changes as well as cellular targets that potentially underlie the functional dysregulation of endothelial cells, astrocytes, and oligodendrocytes in AD, providing important insights for therapeutic development.


Assuntos
Doença de Alzheimer/genética , Núcleo Celular/genética , Células Endoteliais/metabolismo , Neuroglia/metabolismo , Idoso , Idoso de 80 Anos ou mais , Doença de Alzheimer/metabolismo , Células Endoteliais/citologia , Feminino , Perfilação da Expressão Gênica , Humanos , Masculino , Neuroglia/citologia , Córtex Pré-Frontal/citologia , Córtex Pré-Frontal/metabolismo , Análise de Célula Única , Transcriptoma
20.
ACS Chem Neurosci ; 11(18): 2827-2835, 2020 09 16.
Artigo em Inglês | MEDLINE | ID: mdl-32786303

RESUMO

Amyloid-beta peptides generated by ß-secretase- and γ-secretase-mediated successive cleavage of amyloid precursor protein are believed to play a causative role in Alzheimer's disease. Thus, reducing amyloid-beta generation by modulating γ-secretase remains a promising approach for Alzheimer's disease therapeutic development. Here, we screened fruit extracts of Ligustrum lucidum Ait. (Oleaceae) and identified active fractions that increase the C-terminal fragment of amyloid precursor protein and reduce amyloid-beta production in a neuronal cell line. These fractions contain a mixture of two isomeric pentacyclic triterpene natural products, 3-O-cis- or 3-O-trans-p-coumaroyl maslinic acid (OCMA), in different ratios. We further demonstrated that trans-OCMA specifically inhibits γ-secretase and decreases amyloid-beta levels without influencing cleavage of Notch. By using photoactivatable probes targeting the subsites residing in the γ-secretase active site, we demonstrated that trans-OCMA selectively affects the S1 subsite of the active site in this protease. Treatment of Alzheimer's disease transgenic model mice with trans-OCMA or an analogous carbamate derivative of a related pentacyclic triterpene natural product, oleanolic acid, rescued the impairment of synaptic plasticity. This work indicates that the naturally occurring compound trans-OCMA and its analogues could become a promising class of small molecules for Alzheimer's disease treatment.


Assuntos
Doença de Alzheimer , Ligustrum , Doença de Alzheimer/tratamento farmacológico , Secretases da Proteína Precursora do Amiloide , Peptídeos beta-Amiloides , Precursor de Proteína beta-Amiloide/genética , Animais , Camundongos , Triterpenos Pentacíclicos
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