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

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.

2018 ◽  
Vol 115 (46) ◽  
pp. 11826-11831 ◽  
Author(s):  
Alexandra Castillo-Ruiz ◽  
Morgan Mosley ◽  
Andrew J. Jacobs ◽  
Yarely C. Hoffiz ◽  
Nancy G. Forger

Labor and a vaginal delivery trigger changes in peripheral organs that prepare the mammalian fetus to survive ex utero. Surprisingly little attention has been given to whether birth also influences the brain, and to how alterations in birth mode affect neonatal brain development. These are important questions, given the high rates of cesarean section (C-section) delivery worldwide, many of which are elective. We examined the effect of birth mode on neuronal cell death, a widespread developmental process that occurs primarily during the first postnatal week in mice. Timed-pregnant dams were randomly assigned to C-section deliveries that were yoked to vaginal births to carefully match gestation length and circadian time of parturition. Compared with rates of cell death just before birth, vaginally-born offspring had an abrupt, transient decrease in cell death in many brain regions, suggesting that a vaginal delivery is neuroprotective. In contrast, cell death was either unchanged or increased in C-section–born mice. Effects of delivery mode on cell death were greatest for the paraventricular nucleus of the hypothalamus (PVN), which is central to the stress response and brain–immune interactions. The greater cell death in the PVN of C-section–delivered newborns was associated with a reduction in the number of PVN neurons expressing vasopressin at weaning. C-section–delivered mice also showed altered vocalizations in a maternal separation test and greater body mass at weaning. Our results suggest that vaginal birth acutely impacts brain development, and that alterations in birth mode may have lasting consequences.


2021 ◽  
Author(s):  
Alonso Gamero-Quijano ◽  
Shayon Bhattacharya ◽  
Pierre-André Cazade ◽  
Andrés F. Molina-Osorio ◽  
Cillian Beecher ◽  
...  

<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>


2002 ◽  
Vol 383 (5) ◽  
pp. 785-791 ◽  
Author(s):  
Satavisha Dutta ◽  
Yuk Chun Chiu ◽  
Albert W. Probert ◽  
Kevin K.W. Wang

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.


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

2012 ◽  
Vol 443 (3) ◽  
pp. 681-689 ◽  
Author(s):  
Wan Ning Vanessa Chow ◽  
Hon Wing Luk ◽  
Ho Yin Edwin Chan ◽  
Kwok-Fai Lau

An unstable expansion of the polyglutamine repeat within exon 1 of the protein Htt (huntingtin) causes HD (Huntington's disease). Mounting evidence shows that accumulation of N-terminal mutant Htt fragments is the source of disruption of normal cellular processes which ultimately leads to neuronal cell death. Understanding the degradation mechanism of mutant Htt and improving its clearance has emerged as a new direction in developing therapeutic approaches to treat HD. In the present study we show that the brain-enriched adaptor protein FE65 is a novel interacting partner of Htt. The binding is mediated through WW–polyproline interaction and is dependent on the length of the polyglutamine tract. Interestingly, a reduction in mutant Htt protein level was observed in FE65-knockdown cells, and the process requires the UPS (ubiquitin/proteasome system). Moreover, the ubiquitination level of mutant Htt was found to be enhanced when FE65 is knocked down. Immunofluroescence staining revealed that FE65 associates with mutant Htt aggregates. Additionally, we demonstrated that overexpression of FE65 increases mutant Htt-induced cell death both in vitro and in vivo. These results suggest that FE65 facilitates the accumulation of mutant Htt in cells by preventing its degradation via the UPS, and thereby enhances the toxicity of mutant Htt.


2004 ◽  
Vol 123 (1-3) ◽  
pp. 51-59 ◽  
Author(s):  
Dóra Reglödi ◽  
Zsolt Fábián ◽  
Andrea Tamás ◽  
Andrea Lubics ◽  
József Szeberényi ◽  
...  

2020 ◽  
Vol 21 (15) ◽  
pp. 5239 ◽  
Author(s):  
Boris Sabirzhanov ◽  
Oleg Makarevich ◽  
James P. Barrett ◽  
Isabel L. Jackson ◽  
Ethan P. Glaser ◽  
...  

Radiotherapy for brain tumors induces neuronal DNA damage and may lead to neurodegeneration and cognitive deficits. We investigated the mechanisms of radiation-induced neuronal cell death and the role of miR-711 in the regulation of these pathways. We used in vitro and in vivo models of radiation-induced neuronal cell death. We showed that X-ray exposure in primary cortical neurons induced activation of p53-mediated mechanisms including intrinsic apoptotic pathways with sequential upregulation of BH3-only molecules, mitochondrial release of cytochrome c and AIF-1, as well as senescence pathways including upregulation of p21WAF1/Cip1. These pathways of irradiation-induced neuronal apoptosis may involve miR-711-dependent downregulation of pro-survival genes Akt and Ang-1. Accordingly, we demonstrated that inhibition of miR-711 attenuated degradation of Akt and Ang-1 mRNAs and reduced intrinsic apoptosis after neuronal irradiation; likewise, administration of Ang-1 was neuroprotective. Importantly, irradiation also downregulated two novel miR-711 targets, DNA-repair genes Rad50 and Rad54l2, which may impair DNA damage responses, amplifying the stimulation of apoptotic and senescence pathways and contributing to neurodegeneration. Inhibition of miR-711 rescued Rad50 and Rad54l2 expression after neuronal irradiation, enhancing DNA repair and reducing p53-dependent apoptotic and senescence pathways. Significantly, we showed that brain irradiation in vivo persistently elevated miR-711, downregulated its targets, including pro-survival and DNA-repair molecules, and is associated with markers of neurodegeneration, not only across the cortex and hippocampus but also specifically in neurons isolated from the irradiated brain. Our data suggest that irradiation-induced miR-711 negatively modulates multiple pro-survival and DNA-repair mechanisms that converge to activate neuronal intrinsic apoptosis and senescence. Using miR-711 inhibitors to block the development of these regulated neurodegenerative pathways, thus increasing neuronal survival, may be an effective neuroprotective strategy.


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Jin Yu ◽  
Hong Zhu ◽  
Calvin Yeang ◽  
Joseph L Witztum ◽  
Sotirios Tsimikas ◽  
...  

The mechanisms leading to oxidative stress and cellular dysfunction during stroke are not well understood. To test the hypothesis that transient cerebral artery occlusion (MCAo) in mice results in the generation of oxidized phospholipids (oxPLs) that contribute to neuronal cell death and glial activation. Both in vitro and in vivo cerebral ischemia and reperfusion injury (IRI) resulted in the elevation of specific oxPLs. Neuronal cell death was determined in the presence of oxPLs and the natural oxPL E06 antibody protected the cells from the toxic effects. IRI in mice gave rise to increased immunoreactivity of oxPLs in the brain. E06 reduced inflammatory markers in the brain following IRI, including iba-1, GFAP and inflammatory cytokines. In addition, oxPLs gave rise to M1 and Mox microglial phenotypes which was reversed in the presence of E06 and elicited a more M2 phenotype. Nrf2 deficient mice show increased infarct volumes and microglia from Nrf2 -/- mice show a reduction in Mox gene expression, and E06 protects both mice and cells from the Nrf2 deficit. Cerebral IRI generates oxPLs which triggers neuronal cell loss and inflammation and inactivation of oxPLs in vivo reduces infarct volume and improves outcomes.


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