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1.
Biol Res ; 57(1): 56, 2024 Aug 22.
Article in English | MEDLINE | ID: mdl-39175009

ABSTRACT

Synaptic dysfunction is an early feature in Alzheimer's disease (AD) pathogenesis and a major morphological correlate of memory deficits. Given the main synaptic location of N-methyl-D-aspartate receptors (NMDARs), their dysregulation has been implicated in these pathological effects. Here, to detect possible alterations in the expression and synaptic localisation of the GluN1 subunit in the brain of amyloidogenic APP/PS1 mice, we employed histoblot and SDS-digested freeze-fracture replica labelling (SDS-FRL) techniques. Histoblots showed that GluN1 expression was significantly reduced in the hippocampus in a layer-dependent manner, in the cortex and the caudate putamen of APP/PS1 transgenic mice at 12 months of age but was unaltered at 1 and 6 months. Using quantitative SDS-FRL, we unravelled the molecular organisation of GluN1 in seven excitatory synapse populations at a high spatial resolution in the CA1 and CA3 fields and the DG of the hippocampus in 12-month-old APP/PS1 mice. In the CA1 field, the labelling density for GluN1 in the excitatory synapses established on spines and interneurons, was significantly reduced in APP/PS1 mice compared to age-matched wild-type mice in the stratum lacunosum-moleculare but unaltered in the stratum radiatum. In the CA3 field, synaptic GluN1 was reduced in mossy fibre-CA3 pyramidal cell synapses but unaltered in the A/C-CA3 pyramidal cell synapses. In the DG, the density of GluN1 in granule cell-perforant pathway synapses was reduced in APP/PS1 mice. Altogether, our findings provide evidence of specific alterations of synaptic GluN1 in the trisynaptic circuit of the hippocampus in Aß pathology. This differential vulnerability in the disruption of NMDARs may be involved in the mechanisms causing abnormal network activity of the hippocampal circuit and cognitive impairment characteristic of APP/PS1 mice.


Subject(s)
Alzheimer Disease , Hippocampus , Mice, Transgenic , Receptors, N-Methyl-D-Aspartate , Synapses , Animals , Receptors, N-Methyl-D-Aspartate/metabolism , Hippocampus/metabolism , Hippocampus/pathology , Synapses/metabolism , Synapses/pathology , Alzheimer Disease/pathology , Alzheimer Disease/metabolism , Mice , Disease Models, Animal , Male , Amyloid beta-Peptides/metabolism
2.
Cell Mol Life Sci ; 81(1): 342, 2024 Aug 09.
Article in English | MEDLINE | ID: mdl-39123091

ABSTRACT

A Disintegrin And Metalloproteinase 10 (ADAM10) plays a pivotal role in shaping neuronal networks by orchestrating the activity of numerous membrane proteins through the shedding of their extracellular domains. Despite its significance in the brain, the specific cellular localization of ADAM10 remains not well understood due to a lack of appropriate tools. Here, using a specific ADAM10 antibody suitable for immunostainings, we observed that ADAM10 is localized to presynapses and especially enriched at presynaptic vesicles of mossy fiber (MF)-CA3 synapses in the hippocampus. These synapses undergo pronounced frequency facilitation of neurotransmitter release, a process that play critical roles in information transfer and neural computation. We demonstrate, that in conditional ADAM10 knockout mice the ability of MF synapses to undergo this type of synaptic plasticity is greatly reduced. The loss of facilitation depends on the cytosolic domain of ADAM10 and association with the calcium sensor synaptotagmin 7 rather than ADAM10's proteolytic activity. Our findings unveil a new role of ADAM10 in the regulation of synaptic vesicle exocytosis.


Subject(s)
ADAM10 Protein , Amyloid Precursor Protein Secretases , Membrane Proteins , Mice, Knockout , Neuronal Plasticity , Synaptic Vesicles , Animals , ADAM10 Protein/metabolism , ADAM10 Protein/genetics , Neuronal Plasticity/physiology , Amyloid Precursor Protein Secretases/metabolism , Amyloid Precursor Protein Secretases/genetics , Membrane Proteins/metabolism , Membrane Proteins/genetics , Mice , Synaptic Vesicles/metabolism , Mice, Inbred C57BL , Synapses/metabolism , Mossy Fibers, Hippocampal/metabolism , Hippocampus/metabolism , Exocytosis/physiology , Presynaptic Terminals/metabolism , Synaptic Transmission , Synaptotagmins/metabolism , Synaptotagmins/genetics
3.
Sci Rep ; 14(1): 18717, 2024 08 12.
Article in English | MEDLINE | ID: mdl-39134564

ABSTRACT

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder afflicting the elderly population worldwide. The identification of potential gene candidates for AD holds promises for diagnostic biomarkers and therapeutic targets. Employing a comprehensive strategy, this study integrated transcriptomic data from diverse data sources, including microarray and single-cell datasets from blood and tissue samples, enabling a detailed exploration of gene expression dynamics. Through this thorough investigation, 19 notable candidate genes were found with consistent expression changes across both blood and tissue datasets, suggesting their potential as biomarkers for AD. In addition, single cell sequencing analysis further highlighted their specific expression in excitatory and inhibitory neurons, the primary functional units in the brain, underscoring their relevance to AD pathology. Moreover, the functional enrichment analysis revealed that three of the candidate genes were downregulated in synaptic signaling pathway. Further validation experiments significantly showed reduced levels of rabphilin-3A (RPH3A) in 3xTg-AD model mice, implying its role in disease pathogenesis. Given its role in neurotransmitter exocytosis and synaptic function, further investigation into RPH3A and its interactions with neurotrophic proteins may provide valuable insights into the complex molecular mechanisms underlying synaptic dysfunction in AD.


Subject(s)
Alzheimer Disease , Biomarkers , Gene Expression Profiling , Rabphilin-3A , Alzheimer Disease/genetics , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Animals , Mice , Humans , Biomarkers/metabolism , Rabphilin-3A/metabolism , Rabphilin-3A/genetics , Synapses/metabolism , Transcriptome , Disease Models, Animal , Mice, Transgenic , Neurons/metabolism , Single-Cell Analysis/methods
4.
Cell Mol Life Sci ; 81(1): 358, 2024 Aug 19.
Article in English | MEDLINE | ID: mdl-39158722

ABSTRACT

Long-term synaptic plasticity is typically associated with morphological changes in synaptic connections. However, the molecular mechanisms coupling functional and structural aspects of synaptic plasticity are still poorly defined. The catalytic activity of type I phosphoinositide-3-kinase (PI3K) is required for specific forms of synaptic plasticity, such as NMDA receptor-dependent long-term potentiation (LTP) and mGluR-dependent long-term depression (LTD). On the other hand, PI3K signaling has been linked to neuronal growth and synapse formation. Consequently, PI3Ks are promising candidates to coordinate changes in synaptic strength with structural remodeling of synapses. To investigate this issue, we targeted individual regulatory subunits of type I PI3Ks in hippocampal neurons and employed a combination of electrophysiological, biochemical and imaging techniques to assess their role in synaptic plasticity. We found that a particular regulatory isoform, p85α, is selectively required for LTP. This specificity is based on its BH domain, which engages the small GTPases Rac1 and Cdc42, critical regulators of the actin cytoskeleton. Moreover, cofilin, a key regulator of actin dynamics that accumulates in dendritic spines after LTP induction, failed to do so in the absence of p85α or when its BH domain was overexpressed as a dominant negative construct. Finally, in agreement with this convergence on actin regulatory mechanisms, the presence of p85α in the PI3K complex determined the extent of actin polymerization in dendritic spines during LTP. Therefore, this study reveals a molecular mechanism linking structural and functional synaptic plasticity through the coordinate action of PI3K catalytic activity and a specific isoform of the regulatory subunits.


Subject(s)
Actin Depolymerizing Factors , Actins , Dendritic Spines , Hippocampus , Long-Term Potentiation , Animals , Dendritic Spines/metabolism , Long-Term Potentiation/physiology , Actins/metabolism , Hippocampus/metabolism , Hippocampus/cytology , Actin Depolymerizing Factors/metabolism , Rats , rac1 GTP-Binding Protein/metabolism , Synapses/metabolism , Polymerization , cdc42 GTP-Binding Protein/metabolism , Neuronal Plasticity/physiology , Phosphatidylinositol 3-Kinases/metabolism , Class Ia Phosphatidylinositol 3-Kinase/metabolism , Class Ia Phosphatidylinositol 3-Kinase/genetics , Neurons/metabolism , Signal Transduction , Mice , Cells, Cultured
5.
Neuropathol Appl Neurobiol ; 50(4): e13006, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39164997

ABSTRACT

AIMS: Mutations in the MAPT gene encoding tau protein can cause autosomal dominant neurodegenerative tauopathies including frontotemporal dementia (often with Parkinsonism). In Alzheimer's disease, the most common tauopathy, synapse loss is the strongest pathological correlate of cognitive decline. Recently, Positron Emission Tomography (PET) imaging with synaptic tracers revealed clinically relevant loss of synapses in primary tauopathies; however, the molecular mechanisms leading to synapse degeneration in primary tauopathies remain largely unknown. In this study, we examined post-mortem brain tissue from people who died with frontotemporal dementia with tau pathology (FTDtau) caused by the MAPT intronic exon 10 + 16 mutation, which increases splice variants containing exon 10 resulting in higher levels of tau with four microtubule-binding domains. METHODS: We used RNA sequencing and histopathology to examine temporal cortex and visual cortex, to look for molecular phenotypes compared to age, sex and RNA integrity matched participants who died without neurological disease (n = 12 FTDtau10 + 16 and 13 controls). RESULTS: Bulk tissue RNA sequencing reveals substantial downregulation of gene expression associated with synaptic function. Upregulated biological pathways in human MAPT 10 + 16 brain included those involved in transcriptional regulation, DNA damage response and neuroinflammation. Histopathology confirmed increased pathological tau accumulation in FTDtau10 + 16 cortex as well as a loss of presynaptic protein staining and region-specific increased colocalization of phospho-tau with synapses in temporal cortex. CONCLUSIONS: Our data indicate that synaptic pathology likely contributes to pathogenesis in FTDtau10 + 16 caused by the MAPT 10 + 16 mutation.


Subject(s)
Frontotemporal Dementia , Mutation , Synapses , tau Proteins , Humans , tau Proteins/genetics , tau Proteins/metabolism , Frontotemporal Dementia/genetics , Frontotemporal Dementia/pathology , Male , Female , Synapses/pathology , Synapses/metabolism , Aged , Middle Aged , Gene Expression/genetics , Brain/pathology , Brain/metabolism , Tauopathies/genetics , Tauopathies/pathology , Tauopathies/metabolism
6.
J Neurosci ; 44(32)2024 Aug 07.
Article in English | MEDLINE | ID: mdl-39111834

ABSTRACT

MicroRNAs are emerging as crucial regulators within the complex, dynamic environment of the synapse, and they offer a promising new avenue for the treatment of neurological disease. These small noncoding RNAs modify gene expression in several ways, including posttranscriptional modulation via binding to complementary and semicomplementary sites on target mRNAs. This rapid, finely tuned regulation of gene expression is essential to meet the dynamic demands of the synapse. Here, we provide a detailed review of the multifaceted world of synaptic microRNA regulation. We discuss the many mechanisms by which microRNAs regulate gene expression at the synapse, particularly in the context of neuronal plasticity. We also describe the various factors, such as age, sex, and neurological disease, that can influence microRNA expression and activity in neurons. In summary, microRNAs play a crucial role in the intricate and quickly changing functional requirements of the synapse, and context is essential in the study of microRNAs and their potential therapeutic applications.


Subject(s)
Brain , MicroRNAs , Neuronal Plasticity , MicroRNAs/genetics , MicroRNAs/metabolism , Humans , Animals , Brain/metabolism , Neuronal Plasticity/physiology , Neuronal Plasticity/genetics , Synapses/metabolism , Synapses/genetics , Gene Expression Regulation
7.
J Neuroinflammation ; 21(1): 200, 2024 Aug 11.
Article in English | MEDLINE | ID: mdl-39129007

ABSTRACT

BACKGROUND: We recently reported that the dopamine (DA) analogue CA140 modulates neuroinflammatory responses in lipopolysaccharide-injected wild-type (WT) mice and in 3-month-old 5xFAD mice, a model of Alzheimer's disease (AD). However, the effects of CA140 on Aß/tau pathology and synaptic/cognitive function and its molecular mechanisms of action are unknown. METHODS: To investigate the effects of CA140 on cognitive and synaptic function and AD pathology, 3-month-old WT mice or 8-month-old (aged) 5xFAD mice were injected with vehicle (10% DMSO) or CA140 (30 mg/kg, i.p.) daily for 10, 14, or 17 days. Behavioral tests, ELISA, electrophysiology, RNA sequencing, real-time PCR, Golgi staining, immunofluorescence staining, and western blotting were conducted. RESULTS: In aged 5xFAD mice, a model of AD pathology, CA140 treatment significantly reduced Aß/tau fibrillation, Aß plaque number, tau hyperphosphorylation, and neuroinflammation by inhibiting NLRP3 activation. In addition, CA140 treatment downregulated the expression of cxcl10, a marker of AD-associated reactive astrocytes (RAs), and c1qa, a marker of the interaction of RAs with disease-associated microglia (DAMs) in 5xFAD mice. CA140 treatment also suppressed the mRNA levels of s100ß and cxcl10, markers of AD-associated RAs, in primary astrocytes from 5xFAD mice. In primary microglial cells from 5xFAD mice, CA140 treatment increased the mRNA levels of markers of homeostatic microglia (cx3cr1 and p2ry12) and decreased the mRNA levels of a marker of proliferative region-associated microglia (gpnmb) and a marker of lipid-droplet-accumulating microglia (cln3). Importantly, CA140 treatment rescued scopolamine (SCO)-mediated deficits in long-term memory, dendritic spine number, and LTP impairment. In aged 5xFAD mice, these effects of CA140 treatment on cognitive/synaptic function and AD pathology were regulated by dopamine D1 receptor (DRD1)/Elk1 signaling. In primary hippocampal neurons and WT mice, CA140 treatment promoted long-term memory and dendritic spine formation via effects on DRD1/CaMKIIα and/or ERK signaling. CONCLUSIONS: Our results indicate that CA140 improves neuronal/synaptic/cognitive function and ameliorates Aß/tau pathology and neuroinflammation by modulating DRD1 signaling in primary hippocampal neurons, primary astrocytes/microglia, WT mice, and aged 5xFAD mice.


Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Mice, Transgenic , Neuroinflammatory Diseases , Receptors, Dopamine D1 , Signal Transduction , Animals , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Mice , Amyloid beta-Peptides/metabolism , Neuroinflammatory Diseases/drug therapy , Neuroinflammatory Diseases/metabolism , Signal Transduction/drug effects , Signal Transduction/physiology , Receptors, Dopamine D1/metabolism , Synapses/drug effects , Synapses/metabolism , Synapses/pathology , Cognition/drug effects , Dopamine/metabolism , Mice, Inbred C57BL , Male , Humans
8.
Cell Mol Biol Lett ; 29(1): 108, 2024 Aug 10.
Article in English | MEDLINE | ID: mdl-39127627

ABSTRACT

Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation.


Subject(s)
Lipoylation , Neurodegenerative Diseases , Synapses , Humans , Neurodegenerative Diseases/metabolism , Animals , Synapses/metabolism , Acyltransferases/metabolism , Nerve Tissue Proteins/metabolism , Nerve Tissue Proteins/genetics , Synaptic Transmission
9.
Life Sci Alliance ; 7(11)2024 11.
Article in English | MEDLINE | ID: mdl-39134363

ABSTRACT

Synaptic proteins need to be replaced regularly, to maintain function and to prevent damage. It is unclear whether this process, known as protein turnover, relates to synaptic morphology. To test this, we relied on nanoscale secondary ion mass spectrometry, to detect newly synthesized synaptic components in the brains of young adult (6 mo old) and aged mice (24 mo old), and on transmission electron microscopy, to reveal synapse morphology. Several parameters correlated to turnover, including pre- and postsynaptic size, the number of synaptic vesicles and the presence of a postsynaptic nascent zone. In aged mice, the turnover of all brain compartments was reduced by ∼20%. The turnover rates of the pre- and postsynapses correlated well in aged mice, suggesting that they are subject to common regulatory mechanisms. This correlation was poorer in young adult mice, in line with their higher synaptic dynamics. We conclude that synapse turnover is reflected by synaptic morphology.


Subject(s)
Brain , Synapses , Synaptic Vesicles , Animals , Mice , Synapses/metabolism , Brain/metabolism , Synaptic Vesicles/metabolism , Synaptic Vesicles/ultrastructure , Male , Aging/metabolism , Nerve Tissue Proteins/metabolism , Microscopy, Electron, Transmission , Mice, Inbred C57BL
10.
Nat Commun ; 15(1): 6495, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-39090098

ABSTRACT

The evolutionary transition from diffusion-mediated cell-cell communication to faster, targeted synaptic signaling in animal nervous systems is still unclear. Genome sequencing analyses have revealed a widespread distribution of synapse-related genes among early-diverging metazoans, but how synaptic machinery evolved remains largely unknown. Here, we examine the function of neurexins (Nrxns), a family of presynaptic cell adhesion molecules with critical roles in bilaterian chemical synapses, using the cnidarian model, Nematostella vectensis. Delta-Nrxns are expressed mainly in neuronal cell clusters that exhibit both peptidergic and classical neurotransmitter signaling. Knockdown of δ-Nrxn reduces spontaneous peristalsis of N. vectensis polyps. Interestingly, gene knockdown and pharmacological studies suggest that δ-Nrxn is involved in glutamate- and glycine-mediated signaling rather than peptidergic signaling. Knockdown of the epithelial α-Nrxn reveals a major role in cell adhesion between ectodermal and endodermal epithelia. Overall, this study provides molecular, functional, and cellular insights into the pre-neural function of Nrxns, as well as key information for understanding how and why they were recruited to the synaptic machinery.


Subject(s)
Neurexins , Neurons , Sea Anemones , Animals , Cell Adhesion/genetics , Gene Knockdown Techniques , Glutamic Acid/metabolism , Glycine/metabolism , Neural Cell Adhesion Molecules/metabolism , Neural Cell Adhesion Molecules/genetics , Neurons/metabolism , Sea Anemones/genetics , Sea Anemones/metabolism , Signal Transduction , Synapses/metabolism , Neurexins/metabolism
11.
Hippocampus ; 34(9): 491-502, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39091158

ABSTRACT

Hippocampal area CA2 has garnered attention in recent times owing to its significant involvement in social memory and distinctive plasticity characteristics. Research has revealed that the CA2 region demonstrates a remarkable resistance to plasticity, particularly in the Schaffer Collateral (SC)-CA2 pathway. In this study we investigated the role of Nogo-A, a well-known axon growth inhibitor and more recently discovered plasticity regulator, in modulating plasticity within the CA2 region. The findings demonstrate that blocking Nogo-A in male rat hippocampal slices facilitates the establishment of both short-term and long-term plasticity in the SC-CA2 pathway, while having no impact on the Entorhinal Cortical (EC)-CA2 pathway. Additionally, the study reveals that inhibiting Nogo-A enables association between the SC and EC pathways. Mechanistically, we confirm that Nogo-A operates through its well-known co-receptor, p75 neurotrophin receptor (p75NTR), and its downstream signaling factor such as Rho-associated protein kinase (ROCK), as their inhibition also allows plasticity induction in the SC-CA2 pathway. Additionally, the induction of long-term depression (LTD) in both the EC and SC-CA2 pathways led to persistent LTD, which was not affected by Nogo-A inhibition. Our study demonstrates the involvement of Nogo-A mediated signaling mechanisms in limiting synaptic plasticity within the CA2 region.


Subject(s)
CA2 Region, Hippocampal , Neuronal Plasticity , Nogo Proteins , Synapses , Animals , Nogo Proteins/metabolism , Male , Neuronal Plasticity/physiology , Synapses/physiology , Synapses/drug effects , Synapses/metabolism , CA2 Region, Hippocampal/physiology , CA2 Region, Hippocampal/metabolism , CA2 Region, Hippocampal/drug effects , Rats, Sprague-Dawley , Rats , rho-Associated Kinases/metabolism , rho-Associated Kinases/antagonists & inhibitors , Entorhinal Cortex/physiology , Entorhinal Cortex/metabolism , Receptors, Nerve Growth Factor/metabolism , Neural Pathways/physiology , Myelin Proteins/metabolism , Myelin Proteins/genetics , Nerve Tissue Proteins , Receptors, Growth Factor
12.
Proc Natl Acad Sci U S A ; 121(33): e2412457121, 2024 Aug 13.
Article in English | MEDLINE | ID: mdl-39102555
13.
J Photochem Photobiol B ; 258: 112998, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39096719

ABSTRACT

Depression, a multifactorial mental disorder, characterized by cognitive slowing, anxiety, and impaired cognitive function, imposes a significant burden on public health. Photobiomodulation (PBM), involving exposure to sunlight or artificial light at a specific intensity and wavelength for a determined duration, influences brain activity, functional connectivity, and plasticity. It is recognized for its therapeutic efficacy in treating depression, yet its molecular and cellular underpinnings remain obscure. Here, we investigated the impact of PBM with 468 nm light on depression-like behavior and neuronal damage in the chronic unpredictable mild stress (CUMS) murine model, a commonly employed animal model for studying depression. Our results demonstrate that PBM treatment ameliorated behavioral deficits, inhibited neuroinflammation and apoptosis, and notably rejuvenates the hippocampal synaptic function in depressed mice, which may be mainly attributed to the up-regulation of brain-derived neurotrophic factor signaling pathways. In addition, in vitro experiments with a corticosterone-induced hippocampal neuron injury model demonstrate reduced oxidative stress and improved mitochondrial function, further validating the therapeutic potential of PBM. In summary, these findings suggest PBM as a promising, non-invasive treatment for depression, offering insights into its biological mechanisms and potential for clinical application.


Subject(s)
Depression , Disease Models, Animal , Hippocampus , Low-Level Light Therapy , Mitochondria , Animals , Mitochondria/metabolism , Mitochondria/radiation effects , Mice , Depression/metabolism , Depression/therapy , Hippocampus/radiation effects , Hippocampus/metabolism , Male , Brain-Derived Neurotrophic Factor/metabolism , Synapses/radiation effects , Synapses/metabolism , Oxidative Stress/radiation effects , Mice, Inbred C57BL , Neurons/radiation effects , Neurons/metabolism , Neuronal Plasticity/radiation effects , Corticosterone , Behavior, Animal/radiation effects , Apoptosis/radiation effects , Stress, Psychological
14.
Proc Natl Acad Sci U S A ; 121(34): e2312511121, 2024 Aug 20.
Article in English | MEDLINE | ID: mdl-39141354

ABSTRACT

Schizophrenia phenotypes are suggestive of impaired cortical plasticity in the disease, but the mechanisms of these deficits are unknown. Genomic association studies have implicated a large number of genes that regulate neuromodulation and plasticity, indicating that the plasticity deficits have a genetic origin. Here, we used biochemically detailed computational modeling of postsynaptic plasticity to investigate how schizophrenia-associated genes regulate long-term potentiation (LTP) and depression (LTD). We combined our model with data from postmortem RNA expression studies (CommonMind gene-expression datasets) to assess the consequences of altered expression of plasticity-regulating genes for the amplitude of LTP and LTD. Our results show that the expression alterations observed post mortem, especially those in the anterior cingulate cortex, lead to impaired protein kinase A (PKA)-pathway-mediated LTP in synapses containing GluR1 receptors. We validated these findings using a genotyped electroencephalogram (EEG) dataset where polygenic risk scores for synaptic and ion channel-encoding genes as well as modulation of visual evoked potentials were determined for 286 healthy controls. Our results provide a possible genetic mechanism for plasticity impairments in schizophrenia, which can lead to improved understanding and, ultimately, treatment of the disorder.


Subject(s)
Neuronal Plasticity , Schizophrenia , Schizophrenia/genetics , Schizophrenia/physiopathology , Schizophrenia/metabolism , Humans , Neuronal Plasticity/genetics , Computer Simulation , Long-Term Potentiation/genetics , Receptors, AMPA/genetics , Receptors, AMPA/metabolism , Synapses/metabolism , Synapses/genetics , Electroencephalography , Cyclic AMP-Dependent Protein Kinases/metabolism , Cyclic AMP-Dependent Protein Kinases/genetics , Models, Neurological , Long-Term Synaptic Depression/genetics , Male , Evoked Potentials, Visual/physiology
15.
J Cell Mol Med ; 28(15): e18528, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39099086

ABSTRACT

Huanglian Jiedu decoction (HLJD) has been used to treat ischemic stroke in clinic. However, the detailed protective mechanisms of HLJD on ischemic stroke have yet to be elucidated. The aim of this study is to elucidate the underlying pharmacological mechanisms of HLJD based on the inhibition of neuroinflammation and the amelioration of nerve cell damage. A middle cerebral artery occlusion reperfusion (MCAO/R) model was established in rats and received HLJD treatment. Effects of HLJD on neurological function was assessed based on Bederson's score, postural reflex test and asymmetry score. 2, 3, 5-Triphenyltetrazolium chloride (TTC) staining, Hematein and eosin (HE) and Nissl staining were used to observe the pathological changes in brain. Then, transcriptomics was used to screen the differential genes in brain tissue in MCAO/R model rats following HLJD intervention. Subsequently, the effects of HLJD on neutrophil extracellular trap (NET) formation-related neuroinflammation, gamma-aminobutyric acid (GABA)ergic synapse activation, nerve cell damage and proliferation were validated using immunofluorescence, western blot and enzyme-linked immunosorbent assay (ELISA). Our results showed that HLJD intervention reduced the Bederson's score, postural reflex test score and asymmetry score in MCAO/R model rats. Pathological staining indicated that HLJD treatment decreased the cerebral infarction area, mitigated neuronal damage and increased the numbers of Nissl bodies. Transcriptomics suggested that HLJD affected 435 genes in MCAO/R rats. Among them, several genes involving in NET formation and GABAergic synapses pathways were dysregulated. Subsequent experimental validation showed that HLJD reduced the MPO+CitH3+ positive expression area, reduced the protein expression of PAD4, p-P38/P38, p-ERK/ERK and decreased the levels of IL-1ß, IL-6 and TNF-α, reversed the increase of Iba1+TLR4+, Iba1+p65+ and Iba1+NLRP3+ positive expression area in brain. Moreover, HLJD increased GABA levels, elevated the protein expression of GABRG1 and GAT3, decreased the TUNEL positive expression area and increased the Ki67 positive expression area in brain. HLJD intervention exerts a multifaceted positive impact on ischemia-induced cerebral injury in MCAO/R rats. This intervention effectively inhibits neuroinflammation by mitigating NET formation, and concurrently improves nerve cell damage and fosters nerve cell proliferation through activating GABAergic synapses.


Subject(s)
Brain Ischemia , Drugs, Chinese Herbal , Rats, Sprague-Dawley , Synapses , Animals , Drugs, Chinese Herbal/pharmacology , Rats , Male , Synapses/drug effects , Synapses/metabolism , Brain Ischemia/metabolism , Brain Ischemia/drug therapy , Disease Models, Animal , GABAergic Neurons/metabolism , GABAergic Neurons/drug effects , gamma-Aminobutyric Acid/metabolism , Infarction, Middle Cerebral Artery/complications , Reperfusion Injury/drug therapy , Reperfusion Injury/metabolism , Reperfusion Injury/complications , Neuroprotective Agents/pharmacology , Brain/pathology , Brain/metabolism , Brain/drug effects
16.
Nat Commun ; 15(1): 6842, 2024 Aug 09.
Article in English | MEDLINE | ID: mdl-39122700

ABSTRACT

Astrocytes control brain activity via both metabolic processes and gliotransmission, but the physiological links between these functions are scantly known. Here we show that endogenous activation of astrocyte type-1 cannabinoid (CB1) receptors determines a shift of glycolysis towards the lactate-dependent production of D-serine, thereby gating synaptic and cognitive functions in male mice. Mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) are impaired in novel object recognition (NOR) memory. This phenotype is rescued by the gliotransmitter D-serine, by its precursor L-serine, and also by lactate and 3,5-DHBA, an agonist of the lactate receptor HCAR1. Such lactate-dependent effect is abolished when the astrocyte-specific phosphorylated-pathway (PP), which diverts glycolysis towards L-serine synthesis, is blocked. Consistently, lactate and 3,5-DHBA promoted the co-agonist binding site occupancy of CA1 post-synaptic NMDA receptors in hippocampal slices in a PP-dependent manner. Thus, a tight cross-talk between astrocytic energy metabolism and gliotransmission determines synaptic and cognitive processes.


Subject(s)
Astrocytes , Cognition , Glycolysis , Lactic Acid , Mice, Knockout , Serine , Animals , Male , Astrocytes/metabolism , Cognition/physiology , Mice , Lactic Acid/metabolism , Serine/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Receptors, N-Methyl-D-Aspartate/genetics , Hippocampus/metabolism , Synapses/metabolism , Mice, Inbred C57BL , Receptors, G-Protein-Coupled/metabolism , Receptors, G-Protein-Coupled/genetics
17.
Sci Rep ; 14(1): 18002, 2024 08 03.
Article in English | MEDLINE | ID: mdl-39097642

ABSTRACT

Zika virus (ZIKV) infection was first reported in 2015 in Brazil as causing microcephaly and other developmental abnormalities in newborns, leading to the identification of Congenital Zika Syndrome (CZS). Viral infections have been considered an environmental risk factor for neurodevelopmental disorders outcome, such as Autism Spectrum Disorder (ASD). Moreover, not only the infection per se, but maternal immune system activation during pregnancy, has been linked to fetal neurodevelopmental disorders. To understand the impact of ZIKV vertical infection on brain development, we derived induced pluripotent stem cells (iPSC) from Brazilian children born with CZS, some of the patients also being diagnosed with ASD. Comparing iPSC-derived neurons from CZS with a control group, we found lower levels of pre- and postsynaptic proteins and reduced functional synapses by puncta co-localization. Furthermore, neurons and astrocytes derived from the CZS group showed decreased glutamate levels. Additionally, the CZS group exhibited elevated levels of cytokine production, one of which being IL-6, already associated with the ASD phenotype. These preliminary findings suggest that ZIKV vertical infection may cause long-lasting disruptions in brain development during fetal stages, even in the absence of the virus after birth. These disruptions could contribute to neurodevelopmental disorders manifestations such as ASD. Our study contributes with novel knowledge of the CZS outcomes and paves the way for clinical validation and the development of potential interventions to mitigate the impact of ZIKV vertical infection on neurodevelopment.


Subject(s)
Brain , Induced Pluripotent Stem Cells , Infectious Disease Transmission, Vertical , Synapses , Zika Virus Infection , Zika Virus , Humans , Zika Virus Infection/virology , Zika Virus Infection/pathology , Female , Zika Virus/pathogenicity , Synapses/pathology , Synapses/metabolism , Brain/virology , Brain/pathology , Pregnancy , Induced Pluripotent Stem Cells/metabolism , Induced Pluripotent Stem Cells/virology , Neurons/virology , Neurons/metabolism , Neurons/pathology , Male , Astrocytes/virology , Astrocytes/metabolism , Neuroinflammatory Diseases/virology , Neuroinflammatory Diseases/pathology , Neuroinflammatory Diseases/metabolism , Pregnancy Complications, Infectious/virology , Pregnancy Complications, Infectious/pathology , Brazil , Infant, Newborn , Autism Spectrum Disorder/virology , Child
18.
Methods Mol Biol ; 2831: 21-37, 2024.
Article in English | MEDLINE | ID: mdl-39134841

ABSTRACT

Primary neuronal cultures are commonly used to study genetic and exogenous factors influencing neuronal development and maturation. During development, neurons undergo robust morphological changes involving expansion of dendritic arbor, formation of dendritic spines, and expression of synaptic proteins. In this chapter, we will cover methodological approaches allowing quantitative assessment of in vitro cultured neurons. Various quantitative characteristics of dendritic arbor can be derived based on immunostaining against anti-microtubule-associated protein 2 followed by dendrite tracing with the SNT plug-in of the FIJI software package. The number and subtypes of dendritic spines can be assessed by double labeling with DiI and Phalloidin iFluor448 followed by laser scanning confocal microscopy analysis. Finally, expression of presynaptic and postsynaptic proteins can be determined by immunohistochemistry and quantification using several available software packages including FIJI and Imaris, which also allows for 3D rendering and statistical displaying of the expression level of synaptic proteins.


Subject(s)
Dendritic Spines , Neurites , Neurons , Animals , Dendritic Spines/metabolism , Neurons/metabolism , Neurons/cytology , Neurites/metabolism , Microscopy, Confocal , Cells, Cultured , Mice , Software , Immunohistochemistry/methods , Neurogenesis , Microtubule-Associated Proteins/metabolism , Microtubule-Associated Proteins/genetics , Synapses/metabolism
19.
Methods Mol Biol ; 2831: 209-217, 2024.
Article in English | MEDLINE | ID: mdl-39134852

ABSTRACT

Plasticity of synaptic transmission underlies learning and memory. It is accompanied by changes in the density and size of synapses, collectively called structural plasticity. Therefore, understanding the mechanism of structural plasticity is critical for understanding the mechanism of synaptic plasticity. In this chapter, we describe the procedures and equipment required to image structural plasticity of a single dendritic spine, which hosts excitatory synapses in the central nervous system, and underlying molecular interactions/biochemical reactions using two-photon fluorescence lifetime microscopy (2P-FLIM) in combination with Förster resonance energy transfer (FRET)-based biosensors.


Subject(s)
Dendritic Spines , Fluorescence Resonance Energy Transfer , Microscopy, Fluorescence, Multiphoton , Neuronal Plasticity , Dendritic Spines/metabolism , Dendritic Spines/ultrastructure , Dendritic Spines/physiology , Neuronal Plasticity/physiology , Animals , Fluorescence Resonance Energy Transfer/methods , Microscopy, Fluorescence, Multiphoton/methods , Synapses/metabolism , Synapses/physiology , Mice , Biosensing Techniques/methods
20.
J Cell Biol ; 223(9)2024 Sep 02.
Article in English | MEDLINE | ID: mdl-39136998

ABSTRACT

Extracellular vesicles are known for intercellular signaling roles but can also serve to simply dispose of unwanted cargoes. In this issue, Bostelman and Broihier discuss new work from Rodal and colleagues (https://doi.org/10.1083/jcb.202405025) that refutes prior work by showing that extracellular vesicles at Drosophila neuromuscular junctions are not required for signaling and instead likely serve a proteostasis role.


Subject(s)
Extracellular Vesicles , Neuromuscular Junction , Animals , Extracellular Vesicles/metabolism , Neuromuscular Junction/metabolism , Signal Transduction , Synapses/metabolism , Drosophila melanogaster/metabolism , Drosophila Proteins/metabolism , Drosophila Proteins/genetics , Drosophila/metabolism , Cell Communication , Proteostasis
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