scholarly journals LOTUS, an endogenous Nogo receptor antagonist, is involved in synapse and memory formation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ryohei Nishida ◽  
Yuki Kawaguchi ◽  
Junpei Matsubayashi ◽  
Rie Ishikawa ◽  
Satoshi Kida ◽  
...  
Keyword(s):  
Synapse Formation ◽  
Neural Circuit ◽  
Gene Knockout ◽  
Memory Function ◽  
Axon Growth ◽  
Memory Formation ◽  
Social Recognition ◽  
Morris Water Maze Test ◽  
Spatial Learning And Memory ◽  
Nogo Receptor

AbstractThe Nogo signal is involved in impairment of memory formation. We previously reported the lateral olfactory tract usher substance (LOTUS) as an endogenous antagonist of the Nogo receptor 1 that mediates the inhibition of axon growth and synapse formation. Moreover, we found that LOTUS plays an essential role in neural circuit formation and nerve regeneration. However, the effects of LOTUS on synapse formation and memory function have not been elucidated. Here, we clearly showed the involvement of LOTUS in synapse formation and memory function. The cultured hippocampal neurons derived from lotus gene knockout (LOTUS-KO) mice exhibited a decrease in synaptic density compared with those from wild-type mice. We also found decrease of dendritic spine formation in the adult hippocampus of LOTUS-KO mice. Finally, we demonstrated that LOTUS deficiency impairs memory formation in the social recognition test and the Morris water maze test, indicating that LOTUS is involved in functions of social and spatial learning and memory. These findings suggest that LOTUS affects synapse formation and memory function.

Emerging roles for HOX proteins in synaptogenesis

2018 ◽  
Vol 62 (11-12) ◽  
pp. 807-818 ◽  
Author(s):  
Françoise Gofflot ◽  
Benoit Lizen
Keyword(s):  
Cell Fate ◽  
Synapse Formation ◽  
Neural Circuit ◽  
Target Selection ◽  
Axon Growth ◽  
Current Data ◽  
Cell Fate Specification ◽  
Hox Proteins ◽  
Circuit Formation ◽  
Vertebrate Central Nervous System

Neural circuit formation requires the intricate orchestration of multiple developmental events including cell fate specification, cell migration, axon guidance, dendritic growth, synaptic target selection, and synaptogenesis. The HOX proteins are well-known transcriptional regulators that control embryonic development. Investigations into their action in the vertebrate central nervous system have demonstrated pivotal roles in specifying neural subpopulations, but also in several successive steps required for the assembly of neuronal circuitry, such as neuron migration, axon growth and pathfinding and synaptic target selection. Several lines of evidence suggest that the HOX transcription factors could also regulate synaptogenesis processes even after the process of axonal and dendritic guidance has concluded. Here we will review the current data on HOX proteins in neural circuit formation in order to evaluate their potential roles in establishing neuronal connectivity with specific emphasis on synapse formation and maturation.

Effects of Long Noncoding RNA H19 on Isoflurane-Induced Cognitive Dysregulation by Promoting Neuroinflammation

2021 ◽  
pp. 1-11
Author(s):  
Yanhu Ge ◽  
Duomao Lin ◽  
Boqun Cui ◽  
Liang Zhang ◽  
Shurong Li ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Noncoding Rna ◽  
Memory Function ◽  
Morris Water Maze Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Spatial Learning And Memory ◽  
Target Area ◽  
Ht22 Cells

<b><i>Introduction:</i></b> Isoflurane (ISO) may cause neuronal apoptosis and synaptic disorder during development, and damage long-term learning and memory function. This observation aimed to study the function of H19 in vitro and in vivo tests and the further mechanism was identified. <b><i>Methods:</i></b> ISO cell models and rat models were established and reactive oxygen species (ROS) identified. The viability and apoptosis of HT22 cells were detected by the MTT and flow cytometer. Morris water maze test was conducted to analyze the neurotoxicity of ISO on spatial learning and memory ability. Quantitative PCR was the method to verify the expression of H19. The concentration of inflammatory indicators was identified by enzyme-linked immunosorbent assay. <b><i>Results:</i></b> 1.5% and 2% ISO led to the neurotoxicity of HT22 cells and increased expression of H19. Silenced H19 meliorated these adverse impacts of ISO. Interference of H19 exerted neuroprotective roles by repressing modified neurological severity score, inhibiting escape latency, elevating distance and time of target area, and controlling ROS and inflammation. MiR-17-5p might be a promising competing endogenous RNA of H19. The expression of miR-17-5p was reduced in the ISO group and reversed by the absence of H19. <b><i>Conclusion:</i></b> Our results of in vitro and in vivo assay indicated that the absence of HT22 is a neuroprotective regulator of cognition and inflammation by accumulating miR-17-5p.

scholarly journals Filopodial dynamics and growth cone stabilization in Drosophila visual circuit development

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Mehmet Neset Özel ◽  
Marion Langen ◽  
Bassem A Hassan ◽  
P Robin Hiesinger
Keyword(s):  
Growth Cone ◽  
Synapse Formation ◽  
Neural Circuit ◽  
Stochastic Dynamics ◽  
Axon Growth ◽  
Growth Cones ◽  
Direct Role ◽  
Control Growth ◽  
Photoreceptor Neurons ◽  
Circuit Assembly

Filopodial dynamics are thought to control growth cone guidance, but the types and roles of growth cone dynamics underlying neural circuit assembly in a living brain are largely unknown. To address this issue, we have developed long-term, continuous, fast and high-resolution imaging of growth cone dynamics from axon growth to synapse formation in cultured Drosophila brains. Using R7 photoreceptor neurons as a model we show that >90% of the growth cone filopodia exhibit fast, stochastic dynamics that persist despite ongoing stepwise layer formation. Correspondingly, R7 growth cones stabilize early and change their final position by passive dislocation. N-Cadherin controls both fast filopodial dynamics and growth cone stabilization. Surprisingly, loss of N-Cadherin causes no primary targeting defects, but destabilizes R7 growth cones to jump between correct and incorrect layers. Hence, growth cone dynamics can influence wiring specificity without a direct role in target recognition and implement simple rules during circuit assembly.

scholarly journals Endocrine, liver-derived IGF-I is of importance for spatial learning and memory in old mice

2006 ◽  
Vol 189 (3) ◽  
pp. 617-627 ◽  
Author(s):  
J Svensson ◽  
M Diez ◽  
J Engel ◽  
C Wass ◽  
Å Tivesten ◽  
...  
Keyword(s):  
Learning And Memory ◽  
Spatial Learning ◽  
Metabotropic Glutamate Receptor ◽  
Memory Function ◽  
Morris Water Maze Test ◽  
Spatial Learning And Memory ◽  
Mrna Levels ◽  
Age Related ◽  
Igf I ◽  
Old Mice

IGF-I is a neuroprotective hormone, and neurodegenerative disorders, including Alzheimer’s disease, have been associated with decreased serum IGF-I concentration. In this study, IGF-I production was inactivated in the liver of adult mice (LI-IGF-I−/−), resulting in an approximately 80–85% reduction of circulating IGF-I concentrations. In young (6-month-old) mice there was no difference between the LI-IGF-I−/− and the control mice in spatial learning and memory as measured using the Morris water maze test. In old (aged 15 and 18 months) LI-IGF-I−/− mice, however, the acquisition of the spatial task was slower than in the controls. Furthermore, impaired spatial working as well as reference memory was observed in the old LI-IGF−/− mice. Histochemical analyses revealed an increase in dynorphin and enkephalin immunoreactivities but decreased mRNA levels in the hippocampus of old LI-IGF-I−/− mice. These mice also displayed astrocytosis and increased metabotropic glutamate receptor 7a-immunoreactivity. These neurochemical disturbances suggest synaptic dysfunction and early neurodegeneration in old LI-IGF-I−/− mice. The decline in serum IGF-I with increasing age may therefore be important for the age-related decline in memory function.

Berberine nanoencapsulation attenuates hallmarks of scoplomine induced Alzheimer's-like disease in rats

2020 ◽  
Vol 15 ◽  
Author(s):  
Samar R. Saleh ◽  
Mariam M. Abady ◽  
Mohammed Nofal ◽  
Nashwa W. Yassa ◽  
Mohamed S. Abdel-latif ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Histopathological Examination ◽  
Memory Function ◽  
Amyloid Β ◽  
Active Pharmaceutical Ingredient ◽  
Isoquinoline Alkaloid ◽  
Drug Uptake ◽  
Male Rats ◽  
Morris Water Maze Test ◽  
Neuroprotective Effects

Background: Berberine (BBR), an isoquinoline alkaloid, acts as a multipotent active pharmaceutical ingredient to counteract several types of dementia based on its numerous pharmacological actions including antioxidant, antiinflammatory, cholesterol-lowering effect, and inhibition of Aβ production and AChE. However, BBR suffers from poor absorption, bioavailability and brain drug uptake. The present study is directed for the formulation and characterization of Chitosan BBR-nanoparticles (BBR-NPs) as well as the estimation of its neuroprotective effects against scopolamine induced cognitive impairments. Methods: BBR-NPs were formulated using ionic gelation method and tripolyphosphate was chosen as a cross linker. Nanoparticles size, zeta potential, encapsulation efficiency and releasing profile were estimated. To investigate the neuroprotective effects, adult fifty six Wistar male rats were randomly distributed into: three control groups, received saline, polyethylene glycol or chitosan- NPs respectively; induced group, received scopolamine (2 mg/ kg, i.p.) and three treated groups were orally administrated BBR (50 mg/ kg), BBR- NP (7 mg/ kg) and donepezil (2.25 mg/ kg, as positive control) followed by scopolamine injection after 40 min, daily for 4 weeks. Morris water maze test, oxidative stress parameters, cholinergic and amyloid-β processing intermediates as well as neuroplasticity markers and histopathological examination were assessed. Results: Our results showed that BBR- NPs were better than BBR and donepezil as BBR- NPs were powerful inhibitory ligands toward AChE and Aβ42 formation and significantly down regulated Tau, iNOS and BACE gene expression in rats’ hippocampus. BBR-NPs administration, at 1/6 of BBR therapeutic recommended dose, significantly improved learning and memory function. This could be accredited to the diminution of oxidative stress and amyloid-β toxicity in addition to the improvement of the neuroplasticity markers. Conclusions: The enhancing effect of BBR- NPs could be related to the enhancing of its bioavailability, absorption and brain drug uptake which need more investigation in future work.

scholarly journals GABAB receptor antagonist promotes hippocampal neurogenesis and facilitates cognitive function recovery following acute cerebral ischemia in mice

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dan Song ◽  
Yaohua Chen ◽  
Cheng Chen ◽  
Lili Chen ◽  
Oumei Cheng
Keyword(s):  
Cognitive Function ◽  
Cerebral Ischemia ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Hippocampal Neurogenesis ◽  
Morris Water Maze Test ◽  
Spatial Learning And Memory ◽  
In Vitro Experiments ◽  
Adult Mice

Abstract Purpose and background Previous studies have suggested that promoting endogenous neurogenesis has great significance for the recovery of cognitive dysfunction caused by cerebral ischemia (CI). Pharmacological inhibition of GABAB receptor can enhance neurogenesis in adult healthy and depressed mice. In the study, we intended to investigate the effects of GABAB receptor antagonists on cognitive function and hippocampal neurogenesis in mice following CI. Methods Adult mice were subjected to bilateral common carotid artery occlusion (BCCAO) for 20 min to induce CI and treated with CGP52432 (antagonist of GABAB receptor, CGP, 10 mg/kg intraperitoneal injection) starting 24 h after CI. The Morris water maze test was performed to test spatial learning and memory at day 28. Immunofluorescence was applied to detect neurogenesis in the DG region at day 14 and 28. In in vitro experiments, cell proliferation was detected by CCK8 and immunofluorescence, and the expression of cAMP/CREB signaling pathway-related proteins was detected by ELISA assay and Western blot. Results CGP significantly improved spatial learning and memory disorders caused by CI, and it enhanced the proliferation of neural stem cells (NSCs), the number of immature neurons, and the differentiation from newborn cells to neurons. In vitro experiments further confirmed that CGP dose-dependently enhanced the cell viability of NSCs, and immunofluorescence staining showed that CGP promoted the proliferation of NSCs. In addition, treatment with CGP increased the expression of cAMP, PKA, and pCREB in cultured NSCs. Conclusion Inhibition of GABAB receptor can effectively promote hippocampal neurogenesis and improve spatial learning and memory in adult mice following CI.

scholarly journals MicroExonator enables systematic discovery and quantification of microexons across mouse embryonic development

2020 ◽  
Author(s):  
Guillermo E. Parada ◽  
Roberto Munita ◽  
Ilias Georgakopoulos-Soares ◽  
Hugo Fernandez ◽  
Emmanouil Metzakopian ◽  
...  
Keyword(s):  
Neuronal Development ◽  
Synapse Formation ◽  
De Novo ◽  
Axon Growth ◽  
Developmental Time ◽  
Rna Seq ◽  
Mouse Tissues ◽  
Comprehensive Survey ◽  
Mouse Transcript ◽  
Mouse Visual Cortex

AbstractMicroexons, exons that are ≤30 nucleotides, were shown to play key roles in neuronal development, but are difficult to detect and quantify using standard RNA-Seq alignment tools. Here, we present MicroExonator, a novel pipeline for reproducible de novo discovery and quantification of microexons. We processed 289 RNA-seq datasets from eighteen mouse tissues corresponding to nine embryonic and postnatal stages, providing the most comprehensive survey of microexons available for mouse. We detected 2,984 microexons, 332 of which are differentially spliced throughout mouse embryonic brain development, including 29 that are not present in mouse transcript annotation databases. Unsupervised clustering of microexons alone segregates brain tissues by developmental time and further analysis suggest a key function for microexon inclusion in axon growth and synapse formation. Finally, we analysed single-cell RNA-seq data from the mouse visual cortex and we report differential inclusion between neuronal subpopulations, suggesting that some microexons could be cell-type specific.

Hikaru genki protein is secreted into synaptic clefts from an early stage of synapse formation in Drosophila

Development ◽  
1996 ◽  
Vol 122 (2) ◽  
pp. 589-597 ◽  
Author(s):  
M. Hoshino ◽  
E. Suzuki ◽  
Y. Nabeshima ◽  
C. Hama
Keyword(s):  
Critical Period ◽  
Synapse Formation ◽  
Neural Circuits ◽  
Motor Behavior ◽  
Early Stage ◽  
Axon Growth ◽  
Number Of Factors ◽  
Protein Functions ◽  
Abnormal Motor ◽  
Immunohistochemical Analyses

The development of neural circuits is regulated by a large number of factors that are localized at distinct neural sites. We report here the localization of one of these factors, hikaru genki (hig) protein, at synaptic clefts in the pupal and adult nervous systems of Drosophila. In hig mutants, unusually frequent bursting activity of the muscles and abnormal motor behavior during the adult stage suggest the misfunction of neuromuscular circuitry. Our immunohistochemical analyses revealed that hig protein, produced by neurons, is secreted from the presynaptic terminals into the spaces between the presynaptic and postsynaptic terminals. In addition, we have found that the localization of this protein in the synaptic spaces temporally correlates with its functional requirement during a critical period that occurs in the middle stage of pupal formation, a period when a number of dendrite and axon growth cones meet to form synapses. These findings indicate that hig protein functions in the formation of functional neural circuits from the early stages of synapse formation.

scholarly journals Nrf2 Ablation Promotes Alzheimer’s Disease-Like Pathology in APP/PS1 Transgenic Mice: The Role of Neuroinflammation and Oxidative Stress

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Peng Ren ◽  
Jingwei Chen ◽  
Bingxuan Li ◽  
Mengzhou Zhang ◽  
Bei Yang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Transgenic Mice ◽  
Learning And Memory ◽  
Spatial Learning ◽  
Morris Water Maze Test ◽  
Spatial Learning And Memory ◽  
Related Factor ◽  
Qrt Pcr

Introduction. Alzheimer’s disease (AD), the most common neurodegenerative disorder, is characterized by the accumulation of amyloid-β (Aβ) peptide and hyperphosphorylated tau protein. Accumulating evidence has revealed that the slow progressive deterioration of AD is associated with oxidative stress and chronic inflammation in the brain. Nuclear factor erythroid 2- (NF-E2-) related factor 2 (Nrf2), which acts through the Nrf2/ARE pathway, is a key regulator of the antioxidant and anti-inflammatory response. Although recent data show a link between Nrf2 and AD-related cognitive decline, the mechanism is still unknown. Thus, we explored how Nrf2 protects brain cells against the oxidative stress and inflammation of AD in a mouse model of AD (APP/PS1 transgenic (AT) mice) with genetic removal of Nrf2. Methods. The spatial learning and memory abilities of 12-month-old transgenic mice were evaluated using a Morris water maze test. Hippocampal levels of Nrf2, Aβ, and p-tauS404 and of astrocytes and microglia were determined by immunostaining. Inflammatory cytokines were determined by ELISA and quantitative real-time polymerase chain reaction (qRT-PCR). Oxidative stress was measured by 8-hydroxydeoxyguanosine immunohistochemistry, and the antioxidant response was determined by qRT-PCR. Results. The spatial learning and memory abilities of AT mice were impaired after Nrf2 deletion. Aβ and p-tauS404 accumulation was increased in the hippocampus of AT/Nrf2-KO mice. Astroglial and microglial activation was exacerbated, followed by upregulation of the proinflammatory cytokines IL-1β, IL-6, and TNF-α. Conclusion. Our present results show that Nrf2 deficiency aggravates AD-like pathology in AT mice. This phenotype was associated with increased levels of oxidative and proinflammatory markers, which suggests that the Nrf2 pathway may be a promising therapeutic target for AD.

scholarly journals Asymmetry of an intracellular scaffold at vertebrate electrical synapses

2017 ◽  
Author(s):  
Audrey J Marsh ◽  
Jennifer Carlisle Michel ◽  
Anisha P Adke ◽  
Emily L Heckman ◽  
Adam C Miller
Keyword(s):  
Gap Junction ◽  
Synapse Formation ◽  
Neural Circuit ◽  
Electrical Synapse ◽  
Electrical Synapses ◽  
Gap Junction Channels ◽  
Junction Protein ◽  
Chemical Synapses ◽  
And Function

AbstractNeuronal synaptic connections are electrical or chemical and together are essential to dynamically defining neural circuit function. While chemical synapses are well known for their biochemical complexity, electrical synapses are often viewed as comprised solely of neuronal gap junction channels that allow direct ionic and metabolic communication. However, associated with the gap junction channels are structures observed by electron microscopy called the Electrical Synapse Density (ESD). The ESD has been suggested to be critical for the formation and function of the electrical synapse, yet the biochemical makeup of these structures is poorly understood. Here we find that electrical synapse formation in vivo requires an intracellular scaffold called Tight Junction Protein 1b (Tjp1b). Tjp1b is localized to electrical synapses where it is required for the stabilization of the gap junction channels and for electrical synapse function. Strikingly, we find that Tjp1b protein localizes and functions asymmetrically, exclusively on the postsynaptic side of the synapse. Our findings support a novel model in which there is molecular asymmetry at the level of the intracellular scaffold that is required for building the electrical synapse. ESD molecular asymmetries may be a fundamental motif of all nervous systems and could support functional asymmetry at the electrical synapse.

Sign in / Sign up

Export Citation Format

Share Document