scholarly journals Activity-Dependent Callosal Axon Projections in Neonatal Mouse Cerebral Cortex

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Yoshiaki Tagawa ◽  
Tomoo Hirano
Keyword(s):  
Cerebral Cortex ◽  
Ion Channels ◽  
Neuronal Activity ◽  
Intracellular Signaling ◽  
Developmental Disorders ◽  
Genetic Mutation ◽  
Mammalian Brain ◽  
Intracellular Signaling Pathway ◽  
Activity Dependent

Callosal axon projections are among the major long-range axonal projections in the mammalian brain. They are formed during the prenatal and early postnatal periods in the mouse, and their development relies on both activity-independent and -dependent mechanisms. In this paper, we review recent findings about the roles of neuronal activity in callosal axon projections. In addition to the well-documented role of sensory-driven neuronal activity, recent studies using in utero electroporation demonstrated an essential role of spontaneous neuronal activity generated in neonatal cortical circuits. Both presynaptic and postsynaptic neuronal activities are critically involved in the axon development. Studies have begun to reveal intracellular signaling pathway which works downstream of neuronal activity. We also review several distinct patterns of neuronal activity observed in the developing cerebral cortex, which might play roles in activity-dependent circuit construction. Such neuronal activity during the neonatal period can be disrupted by genetic factors, such as mutations in ion channels. It has been speculated that abnormal activity caused by such factors may affect activity-dependent circuit construction, leading to some developmental disorders. We discuss a possibility that genetic mutation in ion channels may impair callosal axon projections through an activity-dependent mechanism.

THE ROLE OF PHOSPHATIDYLINOSITOL-3-KINASE IN CARCINOGENESIS

2017 ◽  
Vol 63 (4) ◽  
pp. 545-556
Author(s):  
Natalya Oskina ◽  
Aleksandr Shcherbakov ◽  
Maksim Filipenko ◽  
Nikolay Kushlinskiy ◽  
L. Ovchinnikova
Keyword(s):  
Genetic Disease ◽  
Intracellular Signaling ◽  
Somatic Mutations ◽  
Pi3k Pathway ◽  
Genetic Alterations ◽  
Phosphatidylinositol 3 Kinase ◽  
Intracellular Signaling Pathway ◽  
Metabolic Activities ◽  
Carcinogenic Process

Currently it is established that cancer is a genetic disease and that somatic mutations are the initiators of the carcinogenic process. The PI3K/AKT/mTOR pathway is an important intracellular signaling pathway regulating the cell growth and metabolic activities. Aberrant activation of the PI3K pathway is commonly observed in many different cancers. In this review we analyze the genetic alterations of PI3K pathway in a variety of human malignancies and discuss their possible implications for diagnosis and therapy.

scholarly journals Advances in understanding the role of cardiac glycosides in control of sodium transport in renal tubules

2014 ◽  
Vol 222 (1) ◽  
pp. R11-R24 ◽  
Author(s):  
Syed Jalal Khundmiri
Keyword(s):  
Heart Failure ◽  
Intracellular Signaling ◽  
Cardiac Contractility ◽  
Myocardial Cell ◽  
Renal Tubules ◽  
Intracellular Signaling Pathway ◽  
Body Sodium ◽  
Membrane Bound ◽  
Total Body

Cardiotonic steroids have been used for the past 200 years in the treatment of congestive heart failure. As specific inhibitors of membrane-bound Na+/K+ATPase, they enhance cardiac contractility through increasing myocardial cell calcium concentration in response to the resulting increase in intracellular Na concentration. The half-minimal concentrations of cardiotonic steroids required to inhibit Na+/K+ATPase range from nanomolar to micromolar concentrations. In contrast, the circulating levels of cardiotonic steroids under physiological conditions are in the low picomolar concentration range in healthy subjects, increasing to high picomolar levels under pathophysiological conditions including chronic kidney disease and heart failure. Little is known about the physiological function of low picomolar concentrations of cardiotonic steroids. Recent studies have indicated that physiological concentrations of cardiotonic steroids acutely stimulate the activity of Na+/K+ATPase and activate an intracellular signaling pathway that regulates a variety of intracellular functions including cell growth and hypertrophy. The effects of circulating cardiotonic steroids on renal salt handling and total body sodium homeostasis are unknown. This review will focus on the role of low picomolar concentrations of cardiotonic steroids in renal Na+/K+ATPase activity, cell signaling, and blood pressure regulation.

scholarly journals Isoform-Specific Roles of ERK1 and ERK2 in Arteriogenesis

Cells ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 38 ◽  
Author(s):  
Nicolas Ricard ◽  
Jiasheng Zhang ◽  
Zhen W. Zhuang ◽  
Michael Simons
Keyword(s):  
Endothelial Cells ◽  
Intracellular Signaling ◽  
Clinical Importance ◽  
Macrophage Infiltration ◽  
Endothelial Cell Proliferation ◽  
Vascular Endothelial ◽  
Ischemic Event ◽  
Intracellular Signaling Pathway ◽  
First Time

Despite the clinical importance of arteriogenesis, this biological process is poorly understood. ERK1 and ERK2 are key components of a major intracellular signaling pathway activated by vascular endothelial growth (VEGF) and FGF2, growth factors critical to arteriogenesis. To investigate the specific role of each ERK isoform in arteriogenesis, we used mice with a global Erk1 knockout as well as Erk1 and Erk2 floxed mice to delete Erk1 or Erk2 in endothelial cells, macrophages, and smooth muscle cells. We found that ERK1 controls macrophage infiltration following an ischemic event. Loss of ERK1 in endothelial cells and macrophages induced an excessive macrophage infiltration leading to an increased but poorly functional arteriogenesis. Loss of ERK2 in endothelial cells leads to a decreased arteriogenesis due to decreased endothelial cell proliferation and a reduced eNOS expression. These findings show for the first time that isoform-specific roles of ERK1 and ERK2 in the control of arteriogenesis.

scholarly journals Neuronal Activity-Dependent Control of Postnatal Neurogenesis and Gliogenesis

2018 ◽  
Vol 41 (1) ◽  
pp. 139-161 ◽  
Author(s):  
Ragnhildur T. Káradóttir ◽  
Chay T. Kuo
Keyword(s):  
Nervous System ◽  
Neuronal Activity ◽  
Molecular Mechanisms ◽  
Driving Forces ◽  
Nervous System Development ◽  
Current Evidence ◽  
Mammalian Brain ◽  
Postnatal Neurogenesis ◽  
Proliferation And Differentiation ◽  
Activity Dependent

The addition of new neurons and oligodendroglia in the postnatal and adult mammalian brain presents distinct forms of gray and white matter plasticity. Substantial effort has been devoted to understanding the cellular and molecular mechanisms controlling postnatal neurogenesis and gliogenesis, revealing important parallels to principles governing the embryonic stages. While during central nervous system development, scripted temporal and spatial patterns of neural and glial progenitor proliferation and differentiation are necessary to create the nervous system architecture, it remains unclear what driving forces maintain and sustain postnatal neural stem cell (NSC) and oligodendrocyte progenitor cell (OPC) production of new neurons and glia. In recent years, neuronal activity has been identified as an important modulator of these processes. Using the distinct properties of neurotransmitter ionotropic and metabotropic channels to signal downstream cellular events, NSCs and OPCs share common features in their readout of neuronal activity patterns. Here we review the current evidence for neuronal activity-dependent control of NSC/OPC proliferation and differentiation in the postnatal brain, highlight some potential mechanisms used by the two progenitor populations, and discuss future studies that might advance these research areas further.

scholarly journals Oxidation Impacts the Intracellular Signaling Machinery in Hematological Disorders

Antioxidants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 353
Author(s):  
Elena Tibaldi ◽  
Enrica Federti ◽  
Alessandro Matte ◽  
Iana Iatcenko ◽  
Anand B. Wilson ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Conformational Changes ◽  
Intracellular Signaling ◽  
Signal Transduction Pathways ◽  
Functional Connection ◽  
Intracellular Signaling Pathway ◽  
Hematological Disorders ◽  
Dynamic Coordination ◽  
Transduction Mechanisms

The dynamic coordination between kinases and phosphatases is crucial for cell homeostasis, in response to different stresses. The functional connection between oxidation and the intracellular signaling machinery still remains to be investigated. In the last decade, several studies have highlighted the role of reactive oxygen species (ROS) as modulators directly targeting kinases, phosphatases, and downstream modulators, or indirectly acting on cysteine residues on kinases/phosphatases resulting in protein conformational changes with modulation of intracellular signaling pathway(s). Translational studies have revealed the important link between oxidation and signal transduction pathways in hematological disorders. The intricate nature of intracellular signal transduction mechanisms, based on the generation of complex networks of different types of signaling proteins, revealed the novel and important role of phosphatases together with kinases in disease mechanisms. Thus, therapeutic approaches to abnormal signal transduction pathways should consider either inhibition of overactivated/accumulated kinases or homeostatic signaling resetting through the activation of phosphatases. This review discusses the progress in the knowledge of the interplay between oxidation and cell signaling, involving phosphatase/kinase systems in models of globally distributed hematological disorders.

scholarly journals Deuterated Glutamate-Mediated Neuronal Activity on Micro-Electrode Arrays

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 830
Author(s):  
Wataru Minoshima ◽  
Kyoko Masui ◽  
Tomomi Tani ◽  
Yasunori Nawa ◽  
Satoshi Fujita ◽  
...  
Keyword(s):  
Spontaneous Activity ◽  
Neuronal Activity ◽  
Hippocampal Neurons ◽  
Neuronal Networks ◽  
Microelectrode Array ◽  
Mammalian Brain ◽  
Electrode Arrays ◽  
Physiological Properties ◽  
Micro Electrode Arrays

The excitatory synaptic transmission is mediated by glutamate (GLU) in neuronal networks of the mammalian brain. In addition to the synaptic GLU, extra-synaptic GLU is known to modulate the neuronal activity. In neuronal networks, GLU uptake is an important role of neurons and glial cells for lowering the concentration of extracellular GLU and to avoid the excitotoxicity. Monitoring the spatial distribution of intracellular GLU is important to study the uptake of GLU, but the approach has been hampered by the absence of appropriate GLU analogs that report the localization of GLU. Deuterium-labeled glutamate (GLU-D) is a promising tracer for monitoring the intracellular concentration of glutamate, but physiological properties of GLU-D have not been studied. Here we study the effects of extracellular GLU-D for the neuronal activity by using primary cultured rat hippocampal neurons that form neuronal networks on microelectrode array. The frequency of firing in the spontaneous activity of neurons increased with the increasing concentration of extracellular GLU-D. The frequency of synchronized burst activity in neurons increased similarly as we observed in the spontaneous activity. These changes of the neuronal activity with extracellular GLU-D were suppressed by antagonists of glutamate receptors. These results suggest that GLU-D can be used as an analog of GLU with equivalent effects for facilitating the neuronal activity. We anticipate GLU-D developing as a promising analog of GLU for studying the dynamics of glutamate during neuronal activity.

scholarly journals Acid-sensing ion channels regulate spontaneous inhibitory activity in the hippocampus: possible implications for epilepsy

2016 ◽  
Vol 371 (1700) ◽  
pp. 20150431 ◽  
Author(s):  
O. Ievglevskyi ◽  
D. Isaev ◽  
O. Netsyk ◽  
A. Romanov ◽  
M. Fedoriuk ◽  
...  
Keyword(s):  
Ion Channels ◽  
Hippocampal Neurons ◽  
Hippocampal Slices ◽  
Synaptic Activity ◽  
Mammalian Brain ◽  
Strong Increase ◽  
Life And Death ◽  
Acid Sensing Ion Channels

Acid-sensing ion channels (ASICs) play an important role in numerous functions in the central and peripheral nervous systems ranging from memory and emotions to pain. The data correspond to a recent notion that each neuron and many glial cells of the mammalian brain express at least one member of the ASIC family. However, the mechanisms underlying the involvement of ASICs in neuronal activity are poorly understood. However, there are two exceptions, namely, the straightforward role of ASICs in proton-based synaptic transmission in certain brain areas and the role of the Ca 2+ -permeable ASIC1a subtype in ischaemic cell death. Using a novel orthosteric ASIC antagonist, we have found that ASICs specifically control the frequency of spontaneous inhibitory synaptic activity in the hippocampus. Inhibition of ASICs leads to a strong increase in the frequency of spontaneous inhibitory postsynaptic currents. This effect is presynaptic because it is fully reproducible in single synaptic boutons attached to isolated hippocampal neurons. In concert with this observation, inhibition of the ASIC current diminishes epileptic discharges in a low Mg 2+ model of epilepsy in hippocampal slices and significantly reduces kainate-induced discharges in the hippocampus in vivo . Our results reveal a significant novel role for ASICs. This article is part of the themed issue ‘Evolution brings Ca 2+ and ATP together to control life and death’.

Bacterial lipopolysaccharide directly induces angiogenesis through TRAF6-mediated activation of NF-κB and c-Jun N-terminal kinase

Blood ◽  
2003 ◽  
Vol 102 (5) ◽  
pp. 1740-1742 ◽  
Author(s):  
Ingrid Pollet ◽  
Christy J. Opina ◽  
Carla Zimmerman ◽  
Kevin G. Leong ◽  
Fred Wong ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Tumor Necrosis Factor Receptor ◽  
Nuclear Factor Κb ◽  
Dominant Negative ◽  
Bacterial Lipopolysaccharide ◽  
Intracellular Signaling Pathway ◽  
Necrosis Factor

AbstractThe intracellular pathways by which inflammatory mediators transmit their angiogenic signals is not well studied. The effects of a potent inflammatory mediator, bacterial lipopolysaccharide (LPS), are transmitted through Toll-like receptors (TLRs). A major, although not exclusive, LPS/TLR intracellular signaling pathway is routed through TNF (tumor necrosis factor) receptor associated factor 6 (TRAF6). In this report we demonstrate that LPS directly stimulates endothelial sprouting in vitro. By blocking TRAF6 activity using retroviral expression of a dominant-negative TRAF6 in endothelial cells, we show that TRAF6 is absolutely required for the LPS-initiated angiogenic response in vitro and in vivo. Inhibition of either c-Jun N-terminal kinase (JNK) activity or nuclear factor κB (NF-κB) activity, downstream of TRAF6, is sufficient to inhibit LPS-induced endothelial sprouting. In contrast, only inhibition of NF-κB, but not JNK, activity blocks basic fibroblast growth factor (bFGF)–induced angiogenesis. Our findings thus demonstrate a direct endothelial-stimulatory role of LPS in initiating angiogenesis through activation of TRAF6-dependent signaling pathways.

scholarly journals Wnt-Frizzled Signaling Regulates Activity-Mediated Synapse Formation

2021 ◽  
Vol 14 ◽  
Author(s):  
Samuel Teo ◽  
Patricia C. Salinas
Keyword(s):  
Wnt Signaling ◽  
Neuronal Activity ◽  
Molecular Mechanisms ◽  
Synapse Formation ◽  
Model Systems ◽  
Mammalian Brain ◽  
Excitatory Synapses ◽  
Wnt Ligands

The formation of synapses is a tightly regulated process that requires the coordinated assembly of the presynaptic and postsynaptic sides. Defects in synaptogenesis during development or in the adult can lead to neurodevelopmental disorders, neurological disorders, and neurodegenerative diseases. In order to develop therapeutic approaches for these neurological conditions, we must first understand the molecular mechanisms that regulate synapse formation. The Wnt family of secreted glycoproteins are key regulators of synapse formation in different model systems from invertebrates to mammals. In this review, we will discuss the role of Wnt signaling in the formation of excitatory synapses in the mammalian brain by focusing on Wnt7a and Wnt5a, two Wnt ligands that play an in vivo role in this process. We will also discuss how changes in neuronal activity modulate the expression and/or release of Wnts, resulting in changes in the localization of surface levels of Frizzled, key Wnt receptors, at the synapse. Thus, changes in neuronal activity influence the magnitude of Wnt signaling, which in turn contributes to activity-mediated synapse formation.

Activity-dependent role of NMDA receptors in transmission of cardiac mechanoreceptor input to the NTS

2003 ◽  
Vol 284 (3) ◽  
pp. H884-H891 ◽  
Author(s):  
J. L. Seagard ◽  
C. Dean ◽  
F. A. Hopp
Keyword(s):  
Arterial Pressure ◽  
Nmda Receptors ◽  
Neuronal Activity ◽  
Nucleus Tractus Solitarius ◽  
Afferent Input ◽  
Nmda Glutamate Receptors ◽  
Anesthetized Dogs ◽  
Activity Dependent ◽  
Different Levels

Evidence suggests that transmission of barosensitive input from arterial baroreceptors and cardiac mechanoreceptors at nucleus tractus solitarius (NTS) neurons involves non- N-methyl-d-aspartate (NMDA) glutamate receptors, but there is a possibility that the contribution of NMDA receptors might increase during periods of increased afferent input, when enhanced neuronal depolarization could increase the activation of NMDA receptors by removal of a Mg2+ block. Thus the effects of NMDA on cardiac mechanoreceptor-modulated NTS neuronal discharges were examined at different levels of arterial pressure used to change cardiac mechanoreceptor afferent input. To determine whether the response was specific to NMDA, (±)-α-amino-3-hydroxy-5-methylisoxazole-4-proprionic acid (AMPA) was also administered at different levels of neuronal discharge. In anesthetized dogs, neuronal activity was recorded from the NTS while NMDA or AMPA was picoejected at high versus low arterial stimulating pressures. NMDA, but not AMPA, produced a significantly greater discharge of mechanoreceptor-driven NTS neurons at higher versus lower levels of stimulating pressure. These data suggest that the role played by NMDA receptors is greater during periods of enhanced neuronal depolarization, which could be produced by increases in afferent barosensitive input.

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