scholarly journals Axonal Transport as an In Vivo Biomarker for Retinal Neuropathy

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1298
Author(s):  
Lucia G. Le Roux ◽  
Xudong Qiu ◽  
Megan C. Jacobsen ◽  
Mark D. Pagel ◽  
Seth T. Gammon ◽  
...  
Keyword(s):  
Axonal Transport ◽  
Vision Loss ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Neuronal Loss ◽  
Fluorescent Imaging ◽  
Imaging Agent ◽  
Imaging Biomarker ◽  
Fast Axonal Transport

We illuminate a possible explanatory pathophysiologic mechanism for retinal cellular neuropathy by means of a novel diagnostic method using ophthalmoscopic imaging and a molecular imaging agent targeted to fast axonal transport. The retinal neuropathies are a group of diseases with damage to retinal neural elements. Retinopathies lead to blindness but are typically diagnosed late, when substantial neuronal loss and vision loss have already occurred. We devised a fluorescent imaging agent based on the non-toxic C fragment of tetanus toxin (TTc), which is taken up and transported in neurons using the highly conserved fast axonal transport mechanism. TTc serves as an imaging biomarker for normal axonal transport and demonstrates impairment of axonal transport early in the course of an N-methyl-D-aspartic acid (NMDA)-induced excitotoxic retinopathy model in rats. Transport-related imaging findings were dramatically different between normal and retinopathic eyes prior to presumed neuronal cell death. This proof-of-concept study provides justification for future clinical translation.

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 Dual Targeting by Inhibition of Phosphoinositide-3-Kinase and Mammalian Target of Rapamycin Attenuates the Neuroinflammatory Responses in Murine Hippocampal Cells and Seizures in C57BL/6 Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Preeti Vyas ◽  
Rajkumar Tulsawani ◽  
Divya Vohora
Keyword(s):  
Cell Signaling ◽  
Day Treatment ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Neuronal Loss ◽  
Ht22 Cells ◽  
Seizure Severity ◽  
Combination Model

Emerging evidence suggests the association of seizures and inflammation; however, underlying cell signaling mechanisms are still not fully understood. Overactivation of phosphoinositide-3-kinases is associated with both neuroinflammation and seizures. Herein, we speculate the PI3K/Akt/mTOR pathway as a promising therapeutic target for neuroinflammation-mediated seizures and associated neurodegeneration. Firstly, we cultured HT22 cells for detection of the downstream cell signaling events activated in a lipopolysaccharide (LPS)-primed pilocarpine (PILO) model. We then evaluated the effects of 7-day treatment of buparlisib (PI3K inhibitor, 25 mg/kg p.o.), dactolisib (PI3K/mTOR inhibitor, 25 mg/kg p.o.), and rapamycin (mTORC1 inhibitor, 10 mg/kg p.o.) in an LPS-primed PILO model of seizures in C57BL/6 mice. LPS priming resulted in enhanced seizure severity and reduced latency. Buparlisib and dactolisib, but not rapamycin, prolonged latency to seizures and reduced neuronal loss, while all drugs attenuated seizure severity. Buparlisib and dactolisib further reduced cellular redox, mitochondrial membrane potential, cleaved caspase-3 and p53, nuclear integrity, and attenuated NF-κB, IL-1β, IL-6, TNF-α, and TGF-β1 and TGF-β2 signaling both in vitro and in vivo post-PILO and LPS+PILO inductions; however, rapamycin mitigated the same only in the PILO model. Both drugs protected against neuronal cell death demonstrating the contribution of this pathway in the seizure-induced neuronal pyknosis; however, rapamycin showed resistance in a combination model. Furthermore, LPS and PILO exposure enhanced pAkt/Akt and phospho-p70S6/total-p70S6 kinase activity, while buparlisib and dactolisib, but not rapamycin, could reduce it in a combination model. Partial rapamycin resistance was observed possibly due to the reactivation of the pathway by a functionally different complex of mTOR, i.e., mTORC2. Our study substantiated the plausible involvement of PI3K-mediated apoptotic and inflammatory pathways in LPS-primed PILO-induced seizures and provides evidence that its modulation constitutes an anti-inflammatory mechanism by which seizure inhibitory effects are observed. We showed dual inhibition by dactolisib as a promising approach. Targeting this pathway at two nodes at a time may provide new avenues for antiseizure therapies.

scholarly journals The Potential Neuroprotective Role of Free and Encapsulated Quercetin Mediated by miRNA against Neurological Diseases

Nutrients ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 1318
Author(s):  
Tarek Benameur ◽  
Raffaella Soleti ◽  
Chiara Porro
Keyword(s):  
Inflammatory Responses ◽  
Pathological Condition ◽  
Neurological Diseases ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
In Vivo Studies ◽  
Innovative Drug ◽  
Chronic Neuroinflammation

Chronic neuroinflammation is a pathological condition of numerous central nervous system (CNS) diseases such as Parkinson’s disease, Alzheimer’s disease, multiple sclerosis, amyotrophic lateral sclerosis and many others. Neuroinflammation is characterized by the microglia activation and concomitant production of pro-inflammatory cytokines leading to an increasing neuronal cell death. The decreased neuroinflammation could be obtained by using natural compounds, including flavonoids known to modulate the inflammatory responses. Among flavonoids, quercetin possess multiple pharmacological applications including anti-inflammatory, antitumoral, antiapoptotic and anti-thrombotic activities, widely demonstrated in both in vitro and in vivo studies. In this review, we describe the recent findings about the neuroprotective action of quercetin by acting with different mechanisms on the microglial cells of CNS. The ability of quercetin to influence microRNA expression represents an interesting skill in the regulation of inflammation, differentiation, proliferation, apoptosis and immune responses. Moreover, in order to enhance quercetin bioavailability and capacity to target the brain, we discuss an innovative drug delivery system. In summary, this review highlighted an important application of quercetin in the modulation of neuroinflammation and prevention of neurological disorders.

Continuation of fast axonal transport in regenerating axons in vitro

1979 ◽  
Vol 57 (11) ◽  
pp. 1251-1255
Author(s):  
M. A. Bisby ◽  
C. E. Hilton
Keyword(s):  
Sciatic Nerve ◽  
Vagus Nerve ◽  
Axonal Transport ◽  
Nerve Injury ◽  
Axon Regeneration ◽  
Free Medium ◽  
Fast Axonal Transport ◽  
Sensory Axons

A previous study by McLean and co-workers reported that regenerating axons of the rabbit vagus nerve were unable to sustain axonal transport in vitro for several months after nerve injury. In contrast, we found that sensory axons of the rat sciatic nerve were able to transport 3H-labeled protein into their regenerating portions distal to the site of injury within a week after injury when placed in vitro. Transport in vitro was not significantly less than transport in axons maintained in vivo for the same period. Transport occurred in the medium that was used by the McLean group, but was significantly reduced in calcium-free medium. When axon regeneration was delared, only small amounts of activity were present in the nerve distal to the site of injury, showing that labeled protein normally present in that part of the nerve was associated with axons and was not a result of local precursor uptake by nonneural elements in the sciatic nerve. We were not able to explain the failure of McLean and co-workers to demonstrate transport in vitro in regenerating vagus nerve, but we conclude that there is no general peculiarity of growing axons that makes them unable to sustain transport in vitro.

scholarly journals Global Reprogramming of Apoptosis-Related Genes during Brain Development

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2901
Author(s):  
Wei Jiang ◽  
Liang Chen ◽  
Sika Zheng
Keyword(s):  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Term Survival ◽  
Apoptosis Pathway ◽  
Apoptotic Gene ◽  
Histone 3 ◽  
Effector Caspase ◽  
Maturation Stages ◽  
Apoptotic Genes

To enable long-term survival, mammalian adult neurons exhibit unique apoptosis competence. Questions remain as to whether and how neurons globally reprogram the expression of apoptotic genes during development. We systematically examined the in vivo expression of 1923 apoptosis-related genes and associated histone modifications at eight developmental ages of mouse brains. Most apoptotic genes displayed consistent temporal patterns across the forebrain, midbrain, and hindbrain, suggesting ubiquitous robust developmental reprogramming. Although both anti- and pro-apoptotic genes can be up- or downregulated, half the regulatory events in the classical apoptosis pathway are downregulation of pro-apoptotic genes. Reduced expression in initiator caspases, apoptosome, and pro-apoptotic Bcl-2 family members restrains effector caspase activation and attenuates neuronal apoptosis. The developmental downregulation of apoptotic genes is attributed to decreasing histone-3-lysine-4-trimethylation (H3K4me3) signals at promoters, where histone-3-lysine-27-trimethylation (H3K27me3) rarely changes. By contrast, repressive H3K27me3 marks are lost in the upregulated gene groups, for which developmental H3K4me3 changes are not predictive. Hence, developing brains remove epigenetic H3K4me3 and H3K27me3 marks on different apoptotic gene groups, contributing to their downregulation and upregulation, respectively. As such, neurons drastically alter global apoptotic gene expression during development to transform apoptosis controls. Research into neuronal cell death should consider maturation stages as a biological variable.

scholarly journals Modulating the Pro-apoptotic Activity of Cytochrome c at a Biomimetic Electrified Interface

2021 ◽  
Author(s):  
Alonso Gamero-Quijano ◽  
Shayon Bhattacharya ◽  
Pierre-André Cazade ◽  
Andrés F. Molina-Osorio ◽  
Cillian Beecher ◽  
...  
Keyword(s):  
Cell Death ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Inner Mitochondrial Membrane ◽  
Foetal Development ◽  
Drug Molecules ◽  
Electrified Interface ◽  
Conformational Plasticity ◽  
Apoptotic Activity

<p>Programmed cell death <i>via</i> apoptosis is a natural defence against excessive cell division, crucial at all stages of life from foetal development to maintenance of homeostasis and elimination of precancerous and senescent cells. Here we demonstrate an electrified liquid bio-interface that replicates the molecular machinery of the inner mitochondrial membrane at the onset of apoptosis. By mimicking <i>in vivo</i> cytochrome <i>c</i> (Cyt <i>c</i>) interactions with cell membranes, our platform allows us to modulate the conformational plasticity of the protein by simply varying the electrochemical environment at an aqueous|organic interface. As proof-of-concept, we use our electrified liquid bio-interface to identify drug molecules that can potentially downregulate Cyt <i>c</i> and protect against uncontrolled neuronal cell death in Alzheimer’s disease and other neurodegenerative disorders.</p>

scholarly journals In vivo regulation of cell death by embryonic (pro)insulin and the insulin receptor during early retinal neurogenesis

Development ◽  
2000 ◽  
Vol 127 (8) ◽  
pp. 1641-1649
Author(s):  
B. Diaz ◽  
J. Serna ◽  
F. De Pablo ◽  
E.J. de la Rosa
Keyword(s):  
Cell Death ◽  
Embryonic Development ◽  
Insulin Receptor ◽  
Neural Development ◽  
Developmental Process ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
In Ovo ◽  
Retinal Neurogenesis

Programmed cell death is an established developmental process in the nervous system. Whereas the regulation and the developmental role of neuronal cell death have been widely demonstrated, the relevance of cell death during early neurogenesis, the cells affected and the identity of regulatory local growth factors remain poorly characterized. We have previously described specific in vivo patterns of apoptosis during early retinal neurogenesis, and that exogenous insulin acts as survival factor (Diaz, B., Pimentel, B., De Pablo, F. and de la Rosa, E. J. (1999) Eur. J. Neurosci. 11, 1624–1632). Proinsulin mRNA was found to be expressed broadly in the early embryonic chick retina, and decreased later between days 6 and 8 of embryonic development, when there was increased expression of insulin-like growth factor I mRNA, absent or very scarce at earlier stages. Consequently, we studied whether proinsulin and/or insulin ((pro)insulin) action in prevention of cell death has physiological relevance during early neural development. In ovo treatment at day 2 of embryonic development with specific antibodies against (pro)insulin or the insulin receptor induced apoptosis in the neuroretina. The distribution of apoptotic cells two days after the blockade was similar to naturally occurring cell death, as visualized by TdT-mediated dUTP nick end labeling. The apoptosis induced by the insulin receptor blockade preferentially affected to the Islet1/2 positive cells, that is, the differentiated retinal ganglion cells. In parallel, the insulin survival effect on cultured retinas correlated with the activation of Akt to a greater extent than with the activation of MAP kinase. These results suggest that the physiological cell death occurring in early stages of retinal development is regulated by locally produced (pro)insulin through the activation of the Akt survival pathway.

Selective Release of Calpain Produced αII-Spectrin (α-Fodrin) Breakdown Products by Acute Neuronal Cell Death

2002 ◽  
Vol 383 (5) ◽  
pp. 785-791 ◽  
Author(s):  
Satavisha Dutta ◽  
Yuk Chun Chiu ◽  
Albert W. Probert ◽  
Kevin K.W. Wang
Keyword(s):  
Cell Death ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Neuronal Injury ◽  
Nmda Receptor Antagonist ◽  
Breakdown Product ◽  
Calpain Inhibitor ◽  
Neural Cells

Abstract Activation of calpain results in the breakdown of α II spectrin (αfodrin), a neuronal cytoskeleton protein, which has previously been detected in various in vitro and in vivo neuronal injury models. In this study, a 150 kDa spectrin breakdown product (SBDP150) was found to be released into the cellconditioned media from SHSY5Y cells treated with the calcium channel opener maitotoxin (MTX). SBDP150 release can be readily quantified on immunoblot using an SBDP150- specific polyclonal antibody. Increase of SBDP150 also correlated with cell death in a timedependent manner. MDL28170, a selective calpain inhibitor, was the only protease inhibitor tested that significantly reduced MTXinduced SBDP150 release. The cellconditioned media of cerebellar granule neurons challenged with excitotoxins (NMDA and kainate) also exhibited a significant increase of SBDP150 that was attenuated by pretreatment with an NMDA receptor antagonist, R()-3-(2-carbopiperazine-4-yl)propyl-1- phosphonic acid (CPP), and MDL28170. In addition, hypoxic/hypoglycemic challenge of cerebrocortical cultures also resulted in SBDP150 liberation into the media. These results support the theory that an antibody based detection of SBDP150 in the cellconditioned media can be utilized to quantify injury to neural cells. Furthermore, SBDP150 may potentially be used as a surrogate biomarker for acute neuronal injury in clinical settings.

scholarly journals Cylindromatosis mediates neuronal cell death in vitro and in vivo

2018 ◽  
Vol 25 (8) ◽  
pp. 1394-1407 ◽  
Author(s):  
Goutham K. Ganjam ◽  
Nicole Angela Terpolilli ◽  
Sebastian Diemert ◽  
Ina Eisenbach ◽  
Lena Hoffmann ◽  
...  
Keyword(s):  
Cell Death ◽  
Neuronal Cell Death ◽  
Neuronal Cell
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