scholarly journals Scapinin-induced Inhibition of Axon Elongation Is Attenuated by Phosphorylation and Translocation to the Cytoplasm

2011 ◽  
Vol 286 (22) ◽  
pp. 19724-19734 ◽  
Author(s):  
Hovik Farghaian ◽  
Yu Chen ◽  
Ada W. Y. Fu ◽  
Amy K. Y. Fu ◽  
Jacque P. K. Ip ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Brain Cortex ◽  
Inhibitory Effect ◽  
Adult Brain ◽  
Actin Binding ◽  
Mutant Form ◽  
Axon Elongation ◽  
Rat Cortical Neurons ◽  
The Brain

Scapinin is an actin- and PP1-binding protein that is exclusively expressed in the brain; however, its function in neurons has not been investigated. Here we show that expression of scapinin in primary rat cortical neurons inhibits axon elongation without affecting axon branching, dendritic outgrowth, or polarity. This inhibitory effect was dependent on its ability to bind actin because a mutant form that does not bind actin had no effect on axon elongation. Immunofluorescence analysis showed that scapinin is predominantly located in the distal axon shaft, cell body, and nucleus of neurons and displays a reciprocal staining pattern to phalloidin, consistent with previous reports that it binds actin monomers to inhibit polymerization. We show that scapinin is phosphorylated at a highly conserved site in the central region of the protein (Ser-277) by Cdk5 in vitro. Expression of a scapinin phospho-mimetic mutant (S277D) restored normal axon elongation without affecting actin binding. Instead, phosphorylated scapinin was sequestered in the cytoplasm of neurons and away from the axon. Because its expression is highest in relatively plastic regions of the adult brain (cortex, hippocampus), scapinin is a new regulator of neurite outgrowth and neuroplasticity in the brain.

BIOCHEMICAL STUDIES ON CHLORPROMAZINE: 1. THE EFFECT OF CHLORPROMAZINE ON RESPIRATORY ACTIVITY OF ISOLATED RAT BRAIN CORTEX

1957 ◽  
Vol 35 (12) ◽  
pp. 1135-1144 ◽  
Author(s):  
O. Lindan ◽  
J. H. Quastel ◽  
S. Sved
Keyword(s):  
Plasma Proteins ◽  
Brain Cortex ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Acid Dyes ◽  
Highly Sensitive ◽  
Binding Power ◽  
The Brain

Chlorpromazine exerts a progressive inhibitory activity (at 0.3–0.6 mM) on the respiration of brain cortex in presence of either glucose, fructose, pyruvate, or L-glutamate. A similar progressive inhibition occurs with other phenothiazine derivatives such as methylene blue and phenergan. However, chlorpromazine does not inhibit oxygen uptake in the presence of succinate. Potassium-stimulated respiration is highly sensitive to chlorpromazine, as it is markedly diminished by 0.2 mM concentration of the drug, a concentration which does not affect the unstimulated respiration. The increased inhibition of potassium-stimulated respiration is only clearly seen during the early part of the experiment.Chlorpromazine is bound by tissue constituents. At a constant concentration of chlorpromazine (0.6 mM), its inhibitory effect on cortical respiration may be abolished by markedly increasing the amount of tissue present. The inhibitory effect of chlorpromazine may be diminished by addition of plasma proteins (αβ-globulin) or by addition of heated homogenized brain, liver, or kidney. No binding occurs with polyglutamic acid, ribonucleic, and deoxyribonucleic acids, but binding does occur with certain acid dyes such as trypan red. Trypan red may be used to immobilize free chlorpromazine. When the latter drug is absorbed, however, by the nervous tissue, the addition of trypan red has no effect on the metabolic inhibitions brought about by the absorbed chlorpromazine.It is concluded that chlorpromazine resembles a large variety of narcotics and anaesthetics in its marked inhibitory effects on potassium-stimulated respiration of the brain. Its action, in vitro, however, differs from that of the narcotics in bringing about progressive, apparently irreversible, inhibitions and in its high binding power with tissue proteins. Such apparently irreversible inhibition is consistent with the conclusion that the drug, after combination with the tissue, gradually diffuses into the cell bringing about metabolic inhibitions.

scholarly journals Inhibition of cPLA2 and sPLA2 Activities in Primary Cultures of Rat Cortical Neurons by Centella asiatica Water Extract

2012 ◽  
Vol 7 (7) ◽  
pp. 1934578X1200700 ◽  
Author(s):  
Patrícia P. Defillipo ◽  
André H. Raposo ◽  
Alessandra G. Fedoce ◽  
Aline S. Ferreira ◽  
Hudson C. Polonini ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Leaf Extract ◽  
Primary Cultures ◽  
Water Extract ◽  
Centella Asiatica ◽  
Long Time ◽  
Rat Cortical Neurons ◽  
Low Toxicity ◽  
The Brain

Leaf extract of Centella asiatica has been used as an alternative medicine for memory improvement in the Indian Ayurvedic system of medicine for a long time. Although several studies have revealed its effect in ameliorating the cognitive impairment in rat models of Alzheimer's disease, the molecular mechanism of C. asiatica on neuroprotection still remains unexplained. In this study, we investigated the effects of C. asiatica water extract on activity of subtypes of phospholipase A2 (PLA2) in primary cultures of rat cortical neurons and quantified by HPLC a possible molecule responsible for the activity. The cPLA2 and sPLA2 activities were inhibited in vitro by asiaticoside present in the water extract of C. asiatica. This extract may be a candidate for the treatment of neurodegenerative processes because of its pharmacological activity in the brain and its low toxicity, as attested by its long popular use as a natural product.

BIOCHEMICAL STUDIES ON CHLORPROMAZINE: 1. THE EFFECT OF CHLORPROMAZINE ON RESPIRATORY ACTIVITY OF ISOLATED RAT BRAIN CORTEX

1957 ◽  
Vol 35 (1) ◽  
pp. 1135-1144 ◽  
Author(s):  
O. Lindan ◽  
J. H. Quastel ◽  
S. Sved
Keyword(s):  
Plasma Proteins ◽  
Brain Cortex ◽  
Inhibitory Effect ◽  
Inhibitory Effects ◽  
Acid Dyes ◽  
Highly Sensitive ◽  
Binding Power ◽  
The Brain

Chlorpromazine exerts a progressive inhibitory activity (at 0.3–0.6 mM) on the respiration of brain cortex in presence of either glucose, fructose, pyruvate, or L-glutamate. A similar progressive inhibition occurs with other phenothiazine derivatives such as methylene blue and phenergan. However, chlorpromazine does not inhibit oxygen uptake in the presence of succinate. Potassium-stimulated respiration is highly sensitive to chlorpromazine, as it is markedly diminished by 0.2 mM concentration of the drug, a concentration which does not affect the unstimulated respiration. The increased inhibition of potassium-stimulated respiration is only clearly seen during the early part of the experiment.Chlorpromazine is bound by tissue constituents. At a constant concentration of chlorpromazine (0.6 mM), its inhibitory effect on cortical respiration may be abolished by markedly increasing the amount of tissue present. The inhibitory effect of chlorpromazine may be diminished by addition of plasma proteins (αβ-globulin) or by addition of heated homogenized brain, liver, or kidney. No binding occurs with polyglutamic acid, ribonucleic, and deoxyribonucleic acids, but binding does occur with certain acid dyes such as trypan red. Trypan red may be used to immobilize free chlorpromazine. When the latter drug is absorbed, however, by the nervous tissue, the addition of trypan red has no effect on the metabolic inhibitions brought about by the absorbed chlorpromazine.It is concluded that chlorpromazine resembles a large variety of narcotics and anaesthetics in its marked inhibitory effects on potassium-stimulated respiration of the brain. Its action, in vitro, however, differs from that of the narcotics in bringing about progressive, apparently irreversible, inhibitions and in its high binding power with tissue proteins. Such apparently irreversible inhibition is consistent with the conclusion that the drug, after combination with the tissue, gradually diffuses into the cell bringing about metabolic inhibitions.

scholarly journals Comparative AAV-eGFP Transgene Expression Using Vector Serotypes 1–9, 7m8, and 8b in Human Pluripotent Stem Cells, RPEs, and Human and Rat Cortical Neurons

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Thu T. Duong ◽  
James Lim ◽  
Vidyullatha Vasireddy ◽  
Tyler Papp ◽  
Hung Nguyen ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Ex Vivo ◽  
Cell Types ◽  
Egfp Expression ◽  
Cell Type ◽  
Egfp Gene ◽  
Rat Cortical Neurons

Recombinant adeno-associated virus (rAAV), produced from a nonpathogenic parvovirus, has become an increasing popular vector for gene therapy applications in human clinical trials. However, transduction and transgene expression of rAAVs can differ acrossin vitroand ex vivo cellular transduction strategies. This study compared 11 rAAV serotypes, carrying one reporter transgene cassette containing a cytomegalovirus immediate-early enhancer (eCMV) and chicken beta actin (CBA) promoter driving the expression of an enhanced green-fluorescent protein (eGFP) gene, which was transduced into four different cell types: human iPSC, iPSC-derived RPE, iPSC-derived cortical, and dissociated embryonic day 18 rat cortical neurons. Each cell type was exposed to three multiplicity of infections (MOI: 1E4, 1E5, and 1E6 vg/cell). After 24, 48, 72, and 96 h posttransduction, GFP-expressing cells were examined and compared across dosage, time, and cell type. Retinal pigmented epithelium showed highest AAV-eGFP expression and iPSC cortical the lowest. At an MOI of 1E6 vg/cell, all serotypes show measurable levels of AAV-eGFP expression; moreover, AAV7m8 and AAV6 perform best across MOI and cell type. We conclude that serotype tropism is not only capsid dependent but also cell type plays a significant role in transgene expression dynamics.

scholarly journals The Carbamate, Physostigmine does not Impair Axonal Transport in Rat Cortical Neurons

2021 ◽  
Vol 16 ◽  
pp. 263310552110202
Author(s):  
Sean X Naughton ◽  
Wayne D Beck ◽  
Zhe Wei ◽  
Guangyu Wu ◽  
Peter W Baas ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Cortical Neurons ◽  
Acetylcholinesterase Inhibitors ◽  
Neurological Deficits ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Rat Cortical Neurons ◽  
Toxicological Mechanism

Among the various chemicals that are commonly used as pesticides, organophosphates (OPs), and to a lesser extent, carbamates, are most frequently associated with adverse long-term neurological consequences. OPs and the carbamate, pyridostigmine, used as a prophylactic drug against potential nerve agent attacks, have also been implicated in Gulf War Illness (GWI), which is often characterized by chronic neurological symptoms. While most OP- and carbamate-based pesticides, and pyridostigmine are relatively potent acetylcholinesterase inhibitors (AChEIs), this toxicological mechanism is inadequate to explain their long-term health effects, especially when no signs of acute cholinergic toxicity are exhibited. Our previous work suggests that a potential mechanism of the long-term neurological deficits associated with OPs is impairment of axonal transport (AXT); however, we had not previously evaluated carbamates for this effect. Here we thus evaluated the carbamate, physostigmine (PHY), a highly potent AChEI, on AXT using an in vitro neuronal live imaging assay that we have previously found to be very sensitive to OP-related deficits in AXT. We first evaluated the OP, diisopropylfluorophosphate (DFP) (concentration range 0.001-10.0 µM) as a reference compound that we found previously to impair AXT and subsequently evaluated PHY (concentration range 0.01-100 nM). As expected, DFP impaired AXT in a concentration-dependent manner, replicating our previously published results. In contrast, none of the concentrations of PHY (including concentrations well above the threshold for impairing AChE) impaired AXT. These data suggest that the long-term neurological deficits associated with some carbamates are not likely due to acute impairments of AXT.

scholarly journals Modulator of apoptosis-1 is a potential therapeutic target in acute ischemic injury

2018 ◽  
Vol 39 (12) ◽  
pp. 2406-2418 ◽  
Author(s):  
Su Jing Chan ◽  
Hui Zhao ◽  
Kazuhide Hayakawa ◽  
Chou Chai ◽  
Chong Teik Tan ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Infarct Volume ◽  
Neuronal Loss ◽  
Ischemic Injury ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
In Vivo Models ◽  
The Brain

Modulator of apoptosis 1 (MOAP-1) is a Bax-associating protein highly enriched in the brain. In this study, we examined the role of MOAP-1 in promoting ischemic injuries following a stroke by investigating the consequences of MOAP-1 overexpression or deficiency in in vitro and in vivo models of ischemic stroke. MOAP-1 overexpressing SH-SY5Y cells showed significantly lower cell viability following oxygen and glucose deprivation (OGD) treatment when compared to control cells. Consistently, MOAP-1−/− primary cortical neurons were observed to be more resistant against OGD treatment than the MOAP-1+/+ primary neurons. In the mouse transient middle cerebral artery occlusion (tMCAO) model, ischemia triggered MOAP-1/Bax association, suggested activation of the MOAP-1-dependent apoptotic cascade. MOAP-1−/− mice were found to exhibit reduced neuronal loss and smaller infarct volume 24 h after tMCAO when compared to MOAP-1+/+ mice. Correspondingly, MOAP-1−/− mice also showed better integrity of neurological functions as demonstrated by their performance in the rotarod test. Therefore, both in vitro and in vivo data presented strongly support the conclusion that MOAP-1 is an important apoptotic modulator in ischemic injury. These results may suggest that a reduction of MOAP-1 function in the brain could be a potential therapeutic approach in the treatment of acute stroke.

scholarly journals Inhibition of the autophagic protein ULK1 attenuates axonal degeneration in vitro and in vivo, enhances translation, and modulates splicing

2020 ◽  
Vol 27 (10) ◽  
pp. 2810-2827 ◽  
Author(s):  
Björn Friedhelm Vahsen ◽  
Vinicius Toledo Ribas ◽  
Jonas Sundermeyer ◽  
Alexander Boecker ◽  
Vivian Dambeck ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Axonal Degeneration ◽  
Dominant Negative ◽  
Focal Lesion ◽  
Pathological Feature ◽  
Nerve Crush ◽  
Cord Injury ◽  
Rat Cortical Neurons

Abstract Axonal degeneration is a key and early pathological feature in traumatic and neurodegenerative disorders of the CNS. Following a focal lesion to axons, extended axonal disintegration by acute axonal degeneration (AAD) occurs within several hours. During AAD, the accumulation of autophagic proteins including Unc-51 like autophagy activating kinase 1 (ULK1) has been demonstrated, but its role is incompletely understood. Here, we study the effect of ULK1 inhibition in different models of lesion-induced axonal degeneration in vitro and in vivo. Overexpression of a dominant negative of ULK1 (ULK1.DN) in primary rat cortical neurons attenuates axotomy-induced AAD in vitro. Both ULK1.DN and the ULK1 inhibitor SBI-0206965 protect against AAD after rat optic nerve crush in vivo. ULK1.DN additionally attenuates long-term axonal degeneration after rat spinal cord injury in vivo. Mechanistically, ULK1.DN decreases autophagy and leads to an mTOR-mediated increase in translational proteins. Consistently, treatment with SBI-0206965 results in enhanced mTOR activation. ULK1.DN additionally modulates the differential splicing of the degeneration-associated genes Kif1b and Ddit3. These findings uncover ULK1 as an important mediator of axonal degeneration in vitro and in vivo, and elucidate its function in splicing, defining it as a putative therapeutic target.

scholarly journals Excitatory pathway engaging glutamate, calcineurin, and NFAT upregulates IL-4 in ischemic neurons to polarize microglia

2019 ◽  
Vol 40 (3) ◽  
pp. 513-527 ◽  
Author(s):  
Shun-Ming Ting ◽  
Xiurong Zhao ◽  
Xueping Zheng ◽  
Jaroslaw Aronowski
Keyword(s):  
Cortical Neurons ◽  
Culture Medium ◽  
Calcineurin Inhibitor ◽  
Glucose Deprivation ◽  
Interleukin 4 ◽  
Activated T Cells ◽  
Injury Model ◽  
Rat Cortical Neurons ◽  
Anti Inflammatory Cytokine

Excitotoxicity and microglia/macrophage over-activation are the important pathogenic steps in brain damage caused by ischemic stroke. Recent studies from our group suggest that the neurons in ischemic penumbra generate an anti-inflammatory cytokine, interleukin-4 (IL-4). This neuron-produced IL-4 could subsequently convert surrounding microglia/macrophages to a reparative (M2)-phenotype. The present study was designed to establish the mechanisms by which neurons under transient ischemic condition produce/secrete IL-4. We employed primary rat cortical neurons and a validated in vitro ischemic injury model involving transient oxygen–glucose deprivation (OGD). We discovered that only sublethal OGD induces IL-4 production/secretion by neurons. We then showed that excitotoxic stimulus (an integral component of OGD-mediated damage) involving N-methyl-D-aspartate (NMDA), and not kainate receptor, triggers neuronal IL-4 production/release. Of note, oxidative stress or pro-apoptotic stimuli did not induce IL-4 production by neurons. Next, using the calcineurin inhibitor FK506, we implicated this phosphatase in activation of the nuclear factor of activated T-cells (NFAT; a transcription factor activated through calcineurin-mediated dephosphorylation) and propose that this pathway is involved in transcriptional upregulation of the IL-4 synthesis in NMDA-treated neurons. Finally, using a transfer of culture medium from NMDA-conditioned neuron to microglia, we showed that the neuronal IL-4 can polarize microglia toward a restorative, phagocytic phenotype.

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