scholarly journals Synaptic plasticity induced by differential manipulation of tonic and phasic motoneurons in Drosophila

2020 ◽  
Author(s):  
Nicole A. Aponte-Santiago ◽  
Kiel G. Ormerod ◽  
Yulia Akbergenova ◽  
J. Troy Littleton
Keyword(s):  
Synaptic Plasticity ◽  
Structural Changes ◽  
Neuromuscular Junctions ◽  
Target Display ◽  
Nervous Systems ◽  
Genetic Manipulations ◽  
Muscle Innervation ◽  
Synaptic Boutons ◽  
Underlying Mechanisms ◽  
And Function

AbstractStructural and functional plasticity induced by neuronal competition is a common feature of developing nervous systems. However, the rules governing how postsynaptic cells differentiate between presynaptic inputs are unclear. In this study we characterized synaptic interactions following manipulations of Ib tonic or Is phasic glutamatergic motoneurons that co-innervate postsynaptic muscles at Drosophila neuromuscular junctions (NMJs). After identifying drivers for each neuronal subtype, we performed ablation or genetic manipulations to alter neuronal activity and examined the effects on synaptic innervation and function. Ablation of either Ib or Is resulted in decreased muscle response, with some functional compensation occurring in the tonic Ib input when Is was missing. In contrast, the phasic Is terminal failed to show functional or structural changes following loss of the co-innervating Ib input. Decreasing the activity of the Ib or Is neuron with tetanus toxin light chain resulted in structural changes in muscle innervation. Decreased Ib activity resulted in reduced active zone (AZ) number and decreased postsynaptic subsynaptic reticulum (SSR) volume, with the emergence of filopodial-like protrusions from synaptic boutons of the Ib input. Decreased Is activity did not induce structural changes at its own synapses, but the co-innervating Ib motoneuron increased the number of synaptic boutons and AZs it formed. These findings indicate tonic and phasic neurons respond independently to changes in activity, with either functional or structural alterations in the tonic motoneuron occurring following ablation or reduced activity of the co-innervating phasic input, respectively.Significance StatementBoth invertebrate and vertebrate nervous systems display synaptic plasticity in response to behavioral experiences, indicating underlying mechanisms emerged early in evolution. How specific neuronal classes innervating the same postsynaptic target display distinct types of plasticity is unclear. Here, we examined if Drosophila tonic Ib and phasic Is motoneurons display competitive or cooperative interactions during innervation of the same muscle, or compensatory changes when the output of one motoneuron is altered. We established a system to differentially manipulate the motoneurons and examined the effects of cell-type specific changes to one of the inputs. Our findings indicate Ib and Is motoneurons respond differently to activity mismatch or loss of the co-innervating input, with the tonic subclass responding robustly compared to phasic motoneurons.

scholarly journals Spindle Activity Orchestrates Plasticity during Development and Sleep

2016 ◽  
Vol 2016 ◽  
pp. 1-14 ◽  
Author(s):  
Christoph Lindemann ◽  
Joachim Ahlbeck ◽  
Sebastian H. Bitzenhofer ◽  
Ileana L. Hanganu-Opatz
Keyword(s):  
Synaptic Plasticity ◽  
Present Knowledge ◽  
Adult Brain ◽  
Future Research ◽  
Brain Areas ◽  
Functional Differences ◽  
Spindle Activity ◽  
Early Brain Development ◽  
Underlying Mechanisms ◽  
And Function

Spindle oscillations have been described during early brain development and in the adult brain. Besides similarities in temporal patterns and involved brain areas, neonatal spindle bursts (NSBs) and adult sleep spindles (ASSs) show differences in their occurrence, spatial distribution, and underlying mechanisms. While NSBs have been proposed to coordinate the refinement of the maturating neuronal network, ASSs are associated with the implementation of acquired information within existing networks. Along with these functional differences, separate synaptic plasticity mechanisms seem to be recruited. Here, we review the generation of spindle oscillations in the developing and adult brain and discuss possible implications of their differences for synaptic plasticity. The first part of the review is dedicated to the generation and function of ASSs with a particular focus on their role in healthy and impaired neuronal networks. The second part overviews the present knowledge of spindle activity during development and the ability of NSBs to organize immature circuits. Studies linking abnormal maturation of brain wiring with neurological and neuropsychiatric disorders highlight the importance to better elucidate neonatal plasticity rules in future research.

scholarly journals Role of MicroRNA in Governing Synaptic Plasticity

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Yuqin Ye ◽  
Hongyu Xu ◽  
Xinhong Su ◽  
Xiaosheng He
Keyword(s):  
Synaptic Plasticity ◽  
Neurological Disorders ◽  
Therapeutic Strategy ◽  
Target Gene ◽  
Synaptic Function ◽  
The Novel ◽  
Individual Mirnas ◽  
Underlying Mechanisms ◽  
And Function

Although synaptic plasticity in neural circuits is orchestrated by an ocean of genes, molecules, and proteins, the underlying mechanisms remain poorly understood. Recently, it is well acknowledged that miRNA exerts widespread regulation over the translation and degradation of target gene in nervous system. Increasing evidence suggests that quite a few specific miRNAs play important roles in various respects of synaptic plasticity including synaptogenesis, synaptic morphology alteration, and synaptic function modification. More importantly, the miRNA-mediated regulation of synaptic plasticity is not only responsible for synapse development and function but also involved in the pathophysiology of plasticity-related diseases. A review is made here on the function of miRNAs in governing synaptic plasticity, emphasizing the emerging regulatory role of individual miRNAs in synaptic morphological and functional plasticity, as well as their implications in neurological disorders. Understanding of the way in which miRNAs contribute to synaptic plasticity provides rational clues in establishing the novel therapeutic strategy for plasticity-related diseases.

scholarly journals Changes of Synaptic Structures Associated with Learning, Memory and Diseases

2018 ◽  
Vol 4 (2) ◽  
pp. 99-117 ◽  
Author(s):  
Yang Yang ◽  
Ju Lu ◽  
Yi Zuo
Keyword(s):  
Synaptic Plasticity ◽  
Laser Scanning ◽  
Structural Changes ◽  
Laser Scanning Microscopy ◽  
Two Photon ◽  
Sensory Experiences ◽  
Synaptic Boutons ◽  
Synaptic Structures

Synaptic plasticity is widely believed to be the cellular basis of learning and memory. It is influenced by various factors including development, sensory experiences, and brain disorders. Long-term synaptic plasticity is accompanied by protein synthesis and trafficking, leading to structural changes of the synapse. In this review, we focus on the synaptic structural plasticity, which has mainly been studied with in vivo two-photon laser scanning microscopy. We also discuss how a special type of synapses, the multi-contact synapses (including those formed by multi-synaptic boutons and multi-synaptic spines), are associated with experience and learning.

scholarly journals Neuroligin 1 regulates spines and synaptic plasticity via LIMK1/cofilin-mediated actin reorganization

2016 ◽  
Vol 212 (4) ◽  
pp. 449-463 ◽  
Author(s):  
An Liu ◽  
Zikai Zhou ◽  
Rui Dang ◽  
Yuehua Zhu ◽  
Junxia Qi ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Synapse Development ◽  
Lim Domain ◽  
Actin Reorganization ◽  
Synaptic Regulation ◽  
Subsequent Activation ◽  
Guanosine Triphosphatase ◽  
Underlying Mechanisms ◽  
And Function ◽  
Activity Dependent

Neuroligin (NLG) 1 is important for synapse development and function, but the underlying mechanisms remain unclear. It is known that at least some aspects of NLG1 function are independent of the presynaptic neurexin, suggesting that the C-terminal domain (CTD) of NLG1 may be sufficient for synaptic regulation. In addition, NLG1 is subjected to activity-dependent proteolytic cleavage, generating a cytosolic CTD fragment, but the significance of this process remains unknown. In this study, we show that the CTD of NLG1 is sufficient to (a) enhance spine and synapse number, (b) modulate synaptic plasticity, and (c) exert these effects via its interaction with spine-associated Rap guanosine triphosphatase–activating protein and subsequent activation of LIM-domain protein kinase 1/cofilin–mediated actin reorganization. Our results provide a novel postsynaptic mechanism by which NLG1 regulates synapse development and function.

Influence of Ascorbic Acid on the Structure and Function of Alpha-2- macroglobulin: Investigations using Spectroscopic and Thermodynamic Techniques

2020 ◽  
Vol 27 (3) ◽  
pp. 201-209
Author(s):  
Syed Saqib Ali ◽  
Mohammad Khalid Zia ◽  
Tooba Siddiqui ◽  
Haseeb Ahsan ◽  
Fahim Halim Khan
Keyword(s):  
Ascorbic Acid ◽  
Conformational Changes ◽  
Structural Changes ◽  
The Body ◽  
Titration Calorimetry ◽  
Spectroscopic Techniques ◽  
Human Beings ◽  
Plasma Ascorbic Acid ◽  
Dietary Antioxidant ◽  
And Function

Background: Ascorbic acid is a classic dietary antioxidant which plays an important role in the body of human beings. It is commonly found in various foods as well as taken as dietary supplement. Objective: The plasma ascorbic acid concentration may range from low, as in chronic or acute oxidative stress to high if delivered intravenously during cancer treatment. Sheep alpha-2- macroglobulin (α2M), a human α2M homologue is a large tetrameric glycoprotein of 630 kDa with antiproteinase activity, found in sheep’s blood. Methods: In the present study, the interaction of ascorbic acid with alpha-2-macroglobulin was explored in the presence of visible light by utilizing various spectroscopic techniques and isothermal titration calorimetry (ITC). Results: UV-vis and fluorescence spectroscopy suggests the formation of a complex between ascorbic acid and α2M apparent by increased absorbance and decreased fluorescence. Secondary structural changes in the α2M were investigated by CD and FT-IR spectroscopy. Our findings suggest the induction of subtle conformational changes in α2M induced by ascorbic acid. Thermodynamics signatures of ascorbic acid and α2M interaction indicate that the binding is an enthalpy-driven process. Conclusion: It is possible that ascorbic acid binds and compromises antiproteinase activity of α2M by inducing changes in the secondary structure of the protein.

scholarly journals Neurological Complications of COVID-19: Underlying Mechanisms and Management

2021 ◽  
Vol 22 (8) ◽  
pp. 4081
Author(s):  
Ghaydaa A. Shehata ◽  
Kevin C. Lord ◽  
Michaela C. Grudzinski ◽  
Mohamed Elsayed ◽  
Ramy Abdelnaby ◽  
...  
Keyword(s):  
Neuromuscular Junctions ◽  
Neurological Complications ◽  
Cerebrovascular Diseases ◽  
World Health ◽  
Neurological Sequelae ◽  
Global Pandemic ◽  
Underlying Mechanisms ◽  
Health Organization ◽  
Demyelinating Disorders ◽  
Taste And Smell

COVID-19 is a severe respiratory disease caused by the newly identified human coronavirus (HCoV) Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The virus was discovered in December 2019, and in March 2020, the disease was declared a global pandemic by the World Health Organization (WHO) due to a high number of cases. Although SARS-CoV-2 primarily affects the respiratory system, several studies have reported neurological complications in COVID-19 patients. Headache, dizziness, loss of taste and smell, encephalitis, encephalopathy, and cerebrovascular diseases are the most common neurological complications that are associated with COVID-19. In addition, seizures, neuromuscular junctions’ disorders, and Guillain–Barré syndrome were reported as complications of COVID-19, as well as neurodegenerative and demyelinating disorders. However, the management of these conditions remains a challenge. In this review, we discuss the prevalence, pathogenesis, and mechanisms of these neurological sequelae that are secondary to SARS-CoV-2 infection. We aim to update neurologists and healthcare workers on the possible neurological complications associated with COVID-19 and the management of these disease conditions.

scholarly journals Intranasal insulin rescues repeated anesthesia-induced deficits in synaptic plasticity and memory and prevents apoptosis in neonatal mice via mTORC1

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patricia Soriano Roque ◽  
Mehdi Hooshmandi ◽  
Laura Neagu-Lund ◽  
Shelly Yin ◽  
Noosha Yousefpour ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Synaptic Plasticity ◽  
General Anesthesia ◽  
Preventive Treatment ◽  
Intranasal Insulin ◽  
Translational Repressor ◽  
Beneficial Effects ◽  
Underlying Mechanisms ◽  
Induced Apoptosis ◽  
Preclinical And Clinical Studies

AbstractLong-lasting cognitive impairment in juveniles undergoing repeated general anesthesia has been observed in numerous preclinical and clinical studies, yet, the underlying mechanisms remain unknown and no preventive treatment is available. We found that daily intranasal insulin administration to juvenile mice for 7 days prior to repeated isoflurane anesthesia rescues deficits in hippocampus-dependent memory and synaptic plasticity in adulthood. Moreover, intranasal insulin prevented anesthesia-induced apoptosis of hippocampal cells, which is thought to underlie cognitive impairment. Inhibition of the mechanistic target of rapamycin complex 1 (mTORC1), a major intracellular effector of insulin receptor, blocked the beneficial effects of intranasal insulin on anesthesia-induced apoptosis. Consistent with this finding, mice lacking mTORC1 downstream translational repressor 4E-BP2 showed no induction of repeated anesthesia-induced apoptosis. Our study demonstrates that intranasal insulin prevents general anesthesia-induced apoptosis of hippocampal cells, and deficits in synaptic plasticity and memory, and suggests that the rescue effect is mediated via mTORC1/4E-BP2 signaling.

scholarly journals Targeting Pin1 for Modulation of Cell Motility and Cancer Therapy

Biomedicines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 359
Author(s):  
Hsiang-Hao Chuang ◽  
Yen-Yi Zhen ◽  
Yu-Chen Tsai ◽  
Cheng-Hao Chuang ◽  
Ming-Shyan Huang ◽  
...  
Keyword(s):  
Cancer Therapy ◽  
Tumor Suppressors ◽  
Protein Conformation ◽  
Genome Stability ◽  
Recent Progress ◽  
Multiple Roles ◽  
Cancer Development ◽  
Cancer Hallmarks ◽  
Underlying Mechanisms ◽  
And Function

Peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (Pin1) specifically binds and isomerizes the phosphorylated serine/threonine-proline (pSer/Thr-Pro) motif, which leads to changes in protein conformation and function. Pin1 is widely overexpressed in cancers and plays an important role in tumorigenesis. Mounting evidence has revealed that targeting Pin1 is a potential therapeutic approach for various cancers by inhibiting cell proliferation, reducing metastasis, and maintaining genome stability. In this review, we summarize the underlying mechanisms of Pin1-mediated upregulation of oncogenes and downregulation of tumor suppressors in cancer development. Furthermore, we also discuss the multiple roles of Pin1 in cancer hallmarks and examine Pin1 as a desirable pharmaceutical target for cancer therapy. We also summarize the recent progress of Pin1-targeted small-molecule compounds for anticancer activity.

Environmental–biomechanical reciprocity and the evolution of plant material properties

2021 ◽  
Author(s):  
Karl J Niklas ◽  
Frank W Telewski
Keyword(s):  
Physical Environment ◽  
Structural Changes ◽  
Abiotic Factors ◽  
Biotic Interactions ◽  
Cellular Solids ◽  
Form And Function ◽  
Evolutionary Innovation ◽  
Plant Form ◽  
And Function ◽  
Abiotic Environmental Factors

Abstract Abiotic–biotic interactions have shaped organic evolution since life first began. Abiotic factors influence growth, survival, and reproductive success, whereas biotic responses to abiotic factors have changed the physical environment (and indeed created new environments). This reciprocity is well illustrated by land plants who begin and end their existence in the same location while growing in size over the course of years or even millennia, during which environment factors change over many orders of magnitude. A biomechanical, ecological, and evolutionary perspective reveals that plants are (i) composed of materials (cells and tissues) that function as cellular solids (i.e. materials composed of one or more solid and fluid phases); (ii) that have evolved greater rigidity (as a consequence of chemical and structural changes in their solid phases); (iii) allowing for increases in body size and (iv) permitting acclimation to more physiologically and ecologically diverse and challenging habitats; which (v) have profoundly altered biotic as well as abiotic environmental factors (e.g. the creation of soils, carbon sequestration, and water cycles). A critical component of this evolutionary innovation is the extent to which mechanical perturbations have shaped plant form and function and how form and function have shaped ecological dynamics over the course of evolution.

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