scholarly journals The Janus face of Ouabain in Na+, K+-ATPase and calcium signalling in neurons

2020 ◽  
Author(s):  
Paula Kinoshita ◽  
Ana Orellana ◽  
Vinicius Nakao ◽  
Natacha de Souza Port´s ◽  
Luis Quintas ◽  
...  
Keyword(s):  
Cell Fate ◽  
Neuronal Death ◽  
Transmembrane Protein ◽  
Calcium Signalling ◽  
Neuronal Cell ◽  
Dependent Manner ◽  
Cell Fate Determination ◽  
Electrochemical Gradient ◽  
Concentration Dependent Manner ◽  
The Brain

Na+,K+ATPase (NKA), a transmembrane protein essential for maintaining the electrochemical gradient across the plasma membrane, acts as a receptor for cardiotonic steroids (CTS) such as ouabain. CTS binding to NKA, triggers signalling pathways or inhibits NKA activity in a concentration-dependent manner, resulting in a modulation of Ca2+ levels, which are essential for homeostasis in neurons. However, most of the pharmacological strategies for avoiding neuronal death do not target NKA activity, due to its complexity and poor comprehension of the mechanisms involved in NKA modulation. The present review aims to discuss two points regarding the interplay between NKA and Ca2+ signalling in the brain: NKA impairment causing illness as well as neuronal death due to Ca2+ signalling and benefits to the brain by modulating NKA activity. These interactions play an essential role in neuronal cell fate determination and are relevant to finding new targets for the treatment of neurodegenerative diseases.

scholarly journals Human Neuronal Cell Lines as An In Vitro Toxicological Tool for the Evaluation of Novel Psychoactive Substances

2021 ◽  
Vol 22 (13) ◽  
pp. 6785
Author(s):  
Valeria Sogos ◽  
Paola Caria ◽  
Clara Porcedda ◽  
Rafaela Mostallino ◽  
Franca Piras ◽  
...  
Keyword(s):  
Cell Death ◽  
Neuronal Cell ◽  
In Vitro Study ◽  
Dependent Manner ◽  
Novel Psychoactive Substances ◽  
Psychoactive Substances ◽  
Concentration Dependent Manner ◽  
Mechanisms Of Toxicity ◽  
Neuronal Cell Lines

Novel psychoactive substances (NPS) are synthetic substances belonging to diverse groups, designed to mimic the effects of scheduled drugs, resulting in altered toxicity and potency. Up to now, information available on the pharmacology and toxicology of these new substances is very limited, posing a considerable challenge for prevention and treatment. The present in vitro study investigated the possible mechanisms of toxicity of two emerging NPS (i) 4′-methyl-alpha-pyrrolidinoexanophenone (3,4-MDPHP), a synthetic cathinone, and (ii) 2-chloro-4,5-methylenedioxymethamphetamine (2-Cl-4,5-MDMA), a phenethylamine. In addition, to apply our model to the class of synthetic opioids, we evaluated the toxicity of fentanyl, as a reference compound for this group of frequently abused substances. To this aim, the in vitro toxic effects of these three compounds were evaluated in dopaminergic-differentiated SH-SY5Y cells. Following 24 h of exposure, all compounds induced a loss of viability, and oxidative stress in a concentration-dependent manner. 2-Cl-4,5-MDMA activates apoptotic processes, while 3,4-MDPHP elicits cell death by necrosis. Fentanyl triggers cell death through both mechanisms. Increased expression levels of pro-apoptotic Bax and caspase 3 activity were observed following 2-Cl-4,5-MDMA and fentanyl, but not 3,4-MDPHP exposure, confirming the different modes of cell death.

scholarly journals Overexpression of Mitochondrial Calcium Uniporter Causes Neuronal Death

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Veronica Granatiero ◽  
Marco Pacifici ◽  
Anna Raffaello ◽  
Diego De Stefani ◽  
Rosario Rizzuto
Keyword(s):  
Cell Fate ◽  
Neuronal Death ◽  
Cortical Neurons ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Neuronal Loss ◽  
Calcium Uniporter ◽  
Organelle Morphology

Neurodegenerative diseases are a large and heterogeneous group of disorders characterized by selective and progressive death of specific neuronal subtypes. In most of the cases, the pathophysiology is still poorly understood, although a number of hypotheses have been proposed. Among these, dysregulation of Ca2+ homeostasis and mitochondrial dysfunction represent two broadly recognized early events associated with neurodegeneration. However, a direct link between these two hypotheses can be drawn. Mitochondria actively participate to global Ca2+ signaling, and increases of [Ca2+] inside organelle matrix are known to sustain energy production to modulate apoptosis and remodel cytosolic Ca2+ waves. Most importantly, while mitochondrial Ca2+ overload has been proposed as the no-return signal, triggering apoptotic or necrotic neuronal death, until now direct evidences supporting this hypothesis, especially in vivo, are limited. Here, we took advantage of the identification of the mitochondrial Ca2+ uniporter (MCU) and tested whether mitochondrial Ca2+ signaling controls neuronal cell fate. We overexpressed MCU both in vitro, in mouse primary cortical neurons, and in vivo, through stereotaxic injection of MCU-coding adenoviral particles in the brain cortex. We first measured mitochondrial Ca2+ uptake using quantitative genetically encoded Ca2+ probes, and we observed that the overexpression of MCU causes a dramatic increase of mitochondrial Ca2+ uptake both at resting and after membrane depolarization. MCU-mediated mitochondrial Ca2+ overload causes alteration of organelle morphology and dysregulation of global Ca2+ homeostasis. Most importantly, MCU overexpression in vivo is sufficient to trigger gliosis and neuronal loss. Overall, we demonstrated that mitochondrial Ca2+ overload is per se sufficient to cause neuronal cell death both in vitro and in vivo, thus highlighting a potential key step in neurodegeneration.

scholarly journals In Vitro Antioxidant Capacity and Neuronal Cell Toxicity of Roots of Ostericum koreanum Maximowicz

2011 ◽  
Vol 8 (3) ◽  
pp. 1451-1455
Author(s):  
Ramalingam Mahesh ◽  
Hyo Won Jung ◽  
Jun Hong Park ◽  
Yong-Ki Park
Keyword(s):  
Cell Viability ◽  
Ethyl Acetate ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Neuronal Cell ◽  
Ethyl Acetate Fraction ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ostericum Koreanum

Ostericum koreanummaximowicz (Umbelliferae), a medicinal herb in Korean Oriental Medicine, has been applied to treat cold, headache, neuralgia and arthralgia. The ethyl acetate fraction ofO. koreanumroot was subjected toin vitroantioxidant activity with different methods for free radical scavenging activities. In addition, the cell viability and nitric oxide release assays were performed here for the first time in neuroblastoma (Neuro-2a) cell cultures. Among all the tested methods, the ethyl acetate fraction was expressed very active, exhibiting a good Trolox equivalent values and IC50, comparable to that of the commercial antioxidants, Trolox and ascorbic acid, respectively. The results showed that there was a reduction of cell viability by the fraction in a concentration dependent manner. These results suggest thatO. koreanumshows good antioxidant activitiesin vitroby inhibiting free radicals. These findings provide a rationale for thein vivotesting. Also, the major constituents behind the antioxidant mechanisms of this fraction warrant further study.

scholarly journals Neuropeptide FF and neuropeptide VF inhibit GABAergic neurotransmission in parvocellular neurons of the rat hypothalamic paraventricular nucleus

2007 ◽  
Vol 292 (5) ◽  
pp. R1872-R1880 ◽  
Author(s):  
Jack H. Jhamandas ◽  
Frédéric Simonin ◽  
Jean-Jacques Bourguignon ◽  
Kim H. Harris
Keyword(s):  
Paraventricular Nucleus ◽  
Hypothalamic Paraventricular Nucleus ◽  
Inhibitory Input ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Gabaergic Neurotransmission ◽  
Whole Cell Patch Clamp ◽  
Neuropeptide Ff ◽  
Parvocellular Neurons ◽  
The Brain

Neuropeptide FF (NPFF) and neuropeptide VF (NPVF) are octapeptides belonging to the RFamide family of peptides that have been implicated in a wide variety of physiological functions in the brain, including central autonomic and neuroendocrine regulation. The effects of these peptides are mediated via NPFF1 and NPFF2 receptors that are abundantly expressed in the rat brain, including the hypothalamic paraventricular nucleus (PVN), an autonomic nucleus critical for the secretion of neurohormones and the regulation of sympathetic outflow. In this study, we examined, using whole cell patch-clamp recordings in the brain slice, the effects of NPFF and NPVF on inhibitory GABAergic synaptic input to parvocellular PVN neurons. Under voltage-clamp conditions, NPFF and NPVF reversibly and in a concentration-dependent manner reduced the evoked bicuculline-sensitive inhibitory postsynaptic currents (IPSCs) in parvocellular PVN neurons by 25 and 31%, respectively. RF9, a potent and selective NPFF receptor antagonist, blocked NPFF-induced reduction of IPSCs. Recordings of miniature IPSCs in these neurons following NPFF and NPVF applications showed a reduction in frequency but not amplitude, indicating a presynaptic locus of action for these peptides. Under current-clamp conditions, NPVF and NPFF caused depolarization (6–9 mV) of neurons that persisted in the presence of TTX but was abolished in the presence of bicuculline. Collectively, these data provide evidence for a disinhibitory role of NPFF and NPVF in the hypothalamic PVN via an attenuation of GABAergic inhibitory input to parvocellular neurons of this nucleus and explain the central autonomic effects of NPFF.

scholarly journals Multiple morphogens and rapid elongation promote segmental patterning during development

2021 ◽  
Author(s):  
Yuchi Qiu ◽  
Lianna Fung ◽  
Thomas F. Schilling ◽  
Qing Nie
Keyword(s):  
Gene Expression ◽  
Gene Regulation ◽  
Cell Fate ◽  
Cell Sorting ◽  
Short Range ◽  
Regulatory Networks ◽  
Dependent Manner ◽  
Convergent Extension ◽  
Concentration Dependent Manner ◽  
Simultaneous Formation

ABSTRACTThe vertebrate hindbrain is segmented into rhombomeres (r) initially defined by distinct domains of gene expression. Previous studies have shown that noise-induced gene regulation and cell sorting are critical for the sharpening of rhombomere boundaries, which start out rough in the forming neural plate (NP) and sharpen over time. However, the mechanisms controlling simultaneous formation of multiple rhombomeres and accuracy in their sizes are unclear. We have developed a stochastic multiscale cell-based model that explicitly incorporates dynamic morphogenetic changes (i.e. convergent-extension of the NP), multiple morphogens, and gene regulatory networks to investigate the formation of rhombomeres and their corresponding boundaries in the zebrafish hindbrain. During pattern initiation, the short-range signal, fibroblast growth factor (FGF), works together with the longer-range morphogen, retinoic acid (RA), to specify all of these boundaries and maintain accurately-sized segments with sharp boundaries. At later stages of patterning, we show a nonlinear change in the shape of rhombomeres with rapid left-right narrowing of the NP followed by slower dynamics. Rapid initial convergence improves boundary sharpness and segment size by regulating cell sorting and cell fate both independently and coordinately. Overall, multiple morphogens and tissue dynamics synergize to regulate the sizes and boundaries of multiple segments during development.Author SummaryIn segmental pattern formation, chemical gradients control gene expression in a concentration-dependent manner to specify distinct gene expression domains. Despite the stochasticity inherent to such biological processes, precise and accurate borders form between segmental gene expression domains. Previous work has revealed synergy between gene regulation and cell sorting in sharpening borders that are initially rough. However, it is still poorly understood how size and boundary sharpness ofmultiplesegments are regulated in a tissue that changes dramatically in its morphology as the embryo develops. Here we develop a stochastic multiscale cell-base model to investigate these questions. Two novel strategies synergize to promote accurate segment formation, a combination of long- and short-range morphogens plus rapid tissue convergence, with one responsible for pattern initiation and the other enabling pattern refinement.

scholarly journals Polarization and cell-fate decision facilitated by the adaptor Ste50 in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Nusrat Sharmeen ◽  
Chris Law ◽  
Cunle Wu
Keyword(s):  
Cell Fate ◽  
Critical Role ◽  
Time Lapse ◽  
Yeast Cells ◽  
Cell Cortex ◽  
Dependent Manner ◽  
Pheromone Response ◽  
Concentration Dependent Manner ◽  
Directional Growth ◽  
Fate Decision

Polarization or directional growth is a major morphological change that occurs in yeast cells during pheromone response to mate with the opposite partner. In the pheromone signaling pathway, the adaptor Ste50 is required to bind MAP3K Ste11 for proper polarization; cells lacking Ste50 are impaired in polarization. Direct involvement of Ste50 in the polarization process has not been explored systematically. Here, we used single-cell fluorescent time-lapse microscopy to characterize Ste50 involvement in the establishment of cell polarity. We found early localization of Ste50 patches on the cell cortex that mark the point of shmoo initiation, these polarity sites move, and patches remain associated with the growing shmoo tip in a pheromone concentration-dependent manner until shmoo maturation. By quantitative analysis we show that polarization corelates with the rising levels of Ste50 enabling rapid individual cell responses to pheromone that corresponds to a critical level of Ste50 at the initial G1 phase. Suggesting Ste50 to be a pheromone responsive gene. We exploited the quantitative differences in the pattern of Ste50 expression to corelate with the cell-cell phenotypic heterogeneity showing Ste50 involvement in the cellular differentiation choices. Taken together, these findings present spatiotemporal localization of Ste50 during yeast polarization, suggesting that Ste50 is a component of the polarisome, and plays a critical role in regulating the polarized growth of shmoo during pheromone response.

scholarly journals IL-6 stimulates a concentration-dependent increase in MCP-1 in immortalised human brain endothelial cells

F1000Research ◽  
2016 ◽  
Vol 5 ◽  
pp. 270 ◽  
Author(s):  
Jai Min Choi ◽  
Odunayo O. Rotimi ◽  
Simon J. O'Carroll ◽  
Louise F.B. Nicholson
Keyword(s):  
Endothelial Cells ◽  
Human Brain ◽  
Systemic Inflammation ◽  
Systemic Circulation ◽  
Dependent Manner ◽  
Brain Endothelial Cells ◽  
Concentration Dependent Manner ◽  
Inflammatory Conditions ◽  
Increased Risk ◽  
The Brain

Systemic inflammation is associated with neurodegeneration, with elevated interleukin-6 (IL-6) in particular being correlated with an increased risk of dementia. The brain endothelial cells of the blood brain barrier (BBB) serve as the interface between the systemic circulation and the brain microenvironment and are therefore likely to be a key player in the development of neuropathology associated with systemic inflammation. Endothelial cells are known to require soluble IL-6 receptor (sIL-6R) in order to respond to IL-6, but studies in rat models have shown that this is not the case for brain endothelial cells and studies conducted in human cells are limited. Here we report for the first time that the human cerebral microvascular cell line, hCMVEC, uses the classical mIL-6R signalling pathway in response to IL-6 in a concentration-dependent manner as measured by the production of monocyte chemotactic protein (MCP-1). This novel finding highlights a unique characteristic of human brain endothelial cells and that further investigation into the phenotype of this cell type is needed to elucidate the mechanisms of BBB pathology in inflammatory conditions.

scholarly journals Rhes, a striatal-enriched protein, promotes mitophagy via Nix

2019 ◽  
Vol 116 (47) ◽  
pp. 23760-23771 ◽  
Author(s):  
Manish Sharma ◽  
Uri Nimrod Ramírez-Jarquín ◽  
Oscar Rivera ◽  
Melissa Kazantzis ◽  
Mehdi Eshraghi ◽  
...  
Keyword(s):  
Cell Death ◽  
Cell Line ◽  
Neuronal Cell ◽  
Dependent Manner ◽  
Systemic Injection ◽  
Neuronal Cell Line ◽  
In The Wild ◽  
Striatal Lesion ◽  
The Brain

Elimination of dysfunctional mitochondria via mitophagy is essential for cell survival and neuronal functions. But, how impaired mitophagy participates in tissue-specific vulnerability in the brain remains unclear. Here, we find that striatal-enriched protein, Rhes, is a critical regulator of mitophagy and striatal vulnerability in brain. In vivo interactome and density fractionation reveal that Rhes coimmunoprecipitates and cosediments with mitochondrial and lysosomal proteins. Live-cell imaging of cultured striatal neuronal cell line shows Rhes surrounds globular mitochondria, recruits lysosomes, and ultimately degrades mitochondria. In the presence of 3-nitropropionic acid (3-NP), an inhibitor of succinate dehydrogenase, Rhes disrupts mitochondrial membrane potential (ΔΨm) and promotes excessive mitophagy and cell death. Ultrastructural analysis reveals that systemic injection of 3-NP in mice promotes globular mitochondria, accumulation of mitophagosomes, and striatal lesion only in the wild-type (WT), but not in the Rhes knockout (KO), striatum, suggesting that Rhes is critical for mitophagy and neuronal death in vivo. Mechanistically, Rhes requires Nix (BNIP3L), a known receptor of mitophagy, to disrupt ΔΨm and promote mitophagy and cell death. Rhes interacts with Nix via SUMO E3-ligase domain, and Nix depletion totally abrogates Rhes-mediated mitophagy and cell death in the cultured striatal neuronal cell line. Finally, we find that Rhes, which travels from cell to cell via tunneling nanotube (TNT)-like cellular protrusions, interacts with dysfunctional mitochondria in the neighboring cell in a Nix-dependent manner. Collectively, Rhes is a major regulator of mitophagy via Nix, which may determine striatal vulnerability in the brain.

CSF acidosis augments ventilation through cholinergic mechanisms

1989 ◽  
Vol 66 (6) ◽  
pp. 2565-2572 ◽  
Author(s):  
M. D. Burton ◽  
D. C. Johnson ◽  
H. Kazemi
Keyword(s):  
Minute Ventilation ◽  
Neuronal Firing ◽  
Base Line ◽  
Dependent Manner ◽  
Acidic Ph ◽  
Cholinergic Mechanisms ◽  
Concentration Dependent Manner ◽  
Positive Effects ◽  
Ventilatory Effects ◽  
The Brain

Ventilation is influenced by the acid-base status of the brain extracellular fluids (ECF). CO2 may affect ventilation independent of changes in H+. Whether the acidic condition directly alters neuronal firing or indirectly alters neuronal firing through changes in endogenous neurotransmitters remains unclear. In this work, ventriculocisternal perfusion (VCP) was used in anesthetized (pentobarbital sodium, 30 mg/kg) spontaneously breathing dogs to study the ventilatory effects of acetylcholine (ACh), eucapnic acidic (pH approximately 7.0) cerebrospinal fluid (CSF), and hypercapnic acidic (pH approximately 7.1) CSF in the absence and presence of atropine (ATR). Each animal served as its own control. Base line was defined during VCP with control mock CSF (pH approximately 7.4). With ATR (4.8 mM) there was an insignificant downward trend in minute ventilation (VE). ACh (6.6 mM) increased VE 53% (n = 12, P less than 0.01), eucapnic acidic CSF increased VE 41% (n = 12, P less than 0.01), and hypercapnic acidic CSF increased VE 47% (n = 6, P less than 0.01). These positive effects on ventilation were not seen in the presence of ATR. This suggests that acidic brain ECF activates ventilatory neurons through muscarinic cholinergic mechanisms. Higher concentrations of ACh increased ventilation in a concentration-dependent manner. Higher concentrations of ATR decreased ventilation progressively, resulting in apnea. The results suggest that ACh plays a significant role in the central augmentation of ventilation when the brain ECF is made acidic by either increasing CSF PCO2 or decreasing CSF bicarbonate.

scholarly journals IRE1 promotes neurodegeneration through autophagy-dependent neuron death in the Drosophila model of Parkinson’s disease

2019 ◽  
Vol 10 (11) ◽  
Author(s):  
Cheng Yan ◽  
Jingqi Liu ◽  
Jiamei Gao ◽  
Ying Sun ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Er Stress ◽  
Cell Fate ◽  
Neuronal Cell ◽  
Dependent Manner ◽  
Neuron Death ◽  
Locomotor Impairment ◽  
Photoreceptor Neurons

Abstract Abnormal aggregation of misfolded pathological proteins in neurons is a prominent feature of neurodegenerative disorders including Parkinson’s disease (PD). Perturbations of proteostasis at the endoplasmic reticulum (ER) triggers ER stress, activating the unfolded protein response (UPR). Chronic ER stress is thought to underlie the death of neurons during the neurodegenerative progression, but the precise mechanism by which the UPR pathways regulate neuronal cell fate remains incompletely understood. Here we report a critical neurodegenerative role for inositol-requiring enzyme 1 (IRE1), the evolutionarily conserved ER stress sensor, in a Drosophila model of PD. We found that IRE1 was hyperactivated upon accumulation of α-synuclein in the fly photoreceptor neurons. Ectopic overexpression of IRE1 was sufficient to trigger autophagy-dependent neuron death in an XBP1-independent, JNK-dependent manner. Furthermore, IRE1 was able to promote dopaminergic neuron loss, progressive locomotor impairment, and shorter lifespan, whereas blocking IRE1 or ATG7 expression remarkably ameliorated the progression of α-synuclein-caused Parkinson’s disease. These results provide in vivo evidence demonstrating that the IRE1 pathway drives PD progression through coupling ER stress to autophagy-dependent neuron death.

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