scholarly journals RACK1 modulates polyglutamine-induced neurodegeneration by promoting ERK degradation in Drosophila

PLoS Genetics ◽  
2021 ◽  
Vol 17 (5) ◽  
pp. e1009558
Author(s):  
Jun Xie ◽  
Yongchao Han ◽  
Tao Wang
Keyword(s):  
Cell Death ◽  
Drug Targets ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Wild Type ◽  
Genome Wide ◽  
A Genome ◽  
Potent Drug ◽  
Biochemical Analyses ◽  
Polyq Diseases

Polyglutamine diseases are neurodegenerative diseases caused by the expansion of polyglutamine (polyQ) tracts within different proteins. Although multiple pathways have been found to modulate aggregation of the expanded polyQ proteins, the mechanisms by which polyQ tracts induced neuronal cell death remain unknown. We conducted a genome-wide genetic screen to identify genes that suppress polyQ-induced neurodegeneration when mutated. Loss of the scaffold protein RACK1 alleviated cell death associated with the expression of polyQ tracts alone, as well as in models of Machado-Joseph disease (MJD) and Huntington’s disease (HD), without affecting proteostasis of polyQ proteins. A genome-wide RNAi screen for modifiers of this rack1 suppression phenotype revealed that knockdown of the E3 ubiquitin ligase, POE (Purity of essence), further suppressed polyQ-induced cell death, resulting in nearly wild-type looking eyes. Biochemical analyses demonstrated that RACK1 interacts with POE and ERK to promote ERK degradation. These results suggest that RACK1 plays a key role in polyQ pathogenesis by promoting POE-dependent degradation of ERK, and implicate RACK1/POE/ERK as potent drug targets for treatment of polyQ diseases.

scholarly journals Identification of Genes Regulating Cell Death inStaphylococcus aureus

2019 ◽  
Author(s):  
Rebecca Yee ◽  
Jie Feng ◽  
Jiou Wang ◽  
Jiazhen Chen ◽  
Ying Zhang
Keyword(s):  
Cell Death ◽  
Acetic Acid ◽  
Drug Targets ◽  
Opportunistic Pathogen ◽  
Infection Model ◽  
Chronic Infections ◽  
Bacterial Cell Death ◽  
Genome Wide ◽  
A Genome ◽  
Genetic Mechanisms

AbstractStaphylococcus aureusis an opportunistic pathogen that causes acute and chronic infections. Due toS. aureus’ s highly resistant and persistent nature, it is paramount to identify better drug targets in order to eradicateS. aureusinfections. Despite the efforts in understanding bacterial cell death, the genes and pathways ofS. aureuscell death remain elusive. Here, we performed a genome-wide screen using a transposon mutant library to study the genetic mechanisms involved inS. aureuscell death. Using a precisely controlled heat-ramp and acetic acid exposure assays, mutations in 27 core genes (hsdR1, hslO, nsaS, sspA, folD, mfd, vraF, kdpB, USA300HOU_2684, 0868, 0369, 0420, 1154, 0142, 0930, 2590, 0997, 2559, 0044, 2004, 1209, 0152, 2455, 0154, 2386, 0232, 0350 involved in transporters, transcription, metabolism, peptidases, kinases, transferases, SOS response, nucleic acid and protein synthesis) caused the bacteria to be more death-resistant. In addition, we identified mutations in core 10 genes (capA, gltT, mnhG1,USA300HOU_1780, 2496, 0200, 2029, 0336, 0329, 2386, involved in transporters, metabolism, transcription, cell wall synthesis) from heat-ramp and acetic acid that caused the bacteria to be more death-sensitive or with defect in persistence. Interestingly, death-resistant mutants were more virulent than the parental strain USA300 and caused increased mortality in aCaenorhabditis elegansinfection model. Conversely, death-sensitive mutants were less persistent and formed less persister cells upon exposure to different classes of antibiotics. These findings provide new insights into the mechanisms ofS. aureuscell death and offer new therapeutic targets for developing more effective treatments caused byS. aureus.

scholarly journals High-Content Genome-Wide RNAi Screen Reveals CCR3 as a Key Mediator of Neuronal Cell Death

eNeuro ◽  
2016 ◽  
Vol 3 (5) ◽  
pp. ENEURO.0185-16.2016 ◽  
Author(s):  
Jianmin Zhang ◽  
Huaishan Wang ◽  
Omar Sherbini ◽  
Emily Ling-lin Pai ◽  
Sung-Ung Kang ◽  
...  
Keyword(s):  
Cell Death ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Rnai Screen ◽  
Genome Wide

scholarly journals SEC24A facilitates colocalization and Ca2+ flux between the endoplasmic reticulum and mitochondria

2021 ◽  
Vol 134 (6) ◽  
Author(s):  
Tamutenda Chidawanyika ◽  
Rajarshi Chakrabarti ◽  
Kathryn S. Beauchemin ◽  
Henry N. Higgs ◽  
Surachai Supattapone
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Fold Increase ◽  
Cellular Mechanism ◽  
Autophagic Flux ◽  
Wild Type ◽  
Genome Wide ◽  
Fold Reduction ◽  
A Genome ◽  
Indicator Dyes

ABSTRACT A genome-wide screen recently identified SEC24A as a novel mediator of thapsigargin-induced cell death in HAP1 cells. Here, we determined the cellular mechanism and specificity of SEC24A-mediated cytotoxicity. Measurement of Ca2+ levels using organelle-specific fluorescent indicator dyes showed that Ca2+ efflux from endoplasmic reticulum (ER) and influx into mitochondria were significantly impaired in SEC24A-knockout cells. Furthermore, SEC24A-knockout cells also showed ∼44% less colocalization of mitochondria and peripheral tubular ER. Knockout of SEC24A, but not its paralogs SEC24B, SEC24C or SEC24D, rescued HAP1 cells from cell death induced by three different inhibitors of sarcoplasmic/endoplasmic reticulum Ca2+ ATPases (SERCA) but not from cell death induced by a topoisomerase inhibitor. Thapsigargin-treated SEC24A-knockout cells showed a ∼2.5-fold increase in autophagic flux and ∼10-fold reduction in apoptosis compared to wild-type cells. Taken together, our findings indicate that SEC24A plays a previously unrecognized role in regulating association and Ca2+ flux between the ER and mitochondria, thereby impacting processes dependent on mitochondrial Ca2+ levels, including autophagy and apoptosis.

scholarly journals Damage to the Endoplasmic Reticulum and Activation of Apoptotic Machinery by Oxidative Stress in Ischemic Neurons

2005 ◽  
Vol 25 (1) ◽  
pp. 41-53 ◽  
Author(s):  
Takeshi Hayashi ◽  
Atsushi Saito ◽  
Shuzo Okuno ◽  
Michel Ferrand-Drake ◽  
Robert L Dodd ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endoplasmic Reticulum ◽  
Cell Death ◽  
Er Stress ◽  
Neuronal Degeneration ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Wild Type ◽  
Transgenic Rats ◽  
The Brain

The endoplasmic reticulum (ER), which plays a role in apoptosis, is susceptible to oxidative stress. Because superoxide is produced in the brain after ischemia/reperfusion, oxidative injury to this organelle may be implicated in ischemic neuronal cell death. Activating transcription factor-4 (ATF-4) and C/EBP-homologous protein (CHOP), both of which are involved in apoptosis, are induced by severe ER stress. Using wild-type and human copper/zinc superoxide dismutase transgenic rats, we observed induction of these molecules in the brain after global cerebral ischemia and compared them with neuronal degeneration. In ischemic, wild-type brains, expression of ATF-4 and CHOP was increased in the hippocampal CA1 neurons that would later undergo apoptosis. Transgenic rats had a mild increase in ATF-4 and CHOP and minimal neuronal degeneration, indicating that superoxide was involved in ER stress-induced cell death. We further confirmed attenuation on induction of these molecules in transgenic mouse brains after focal ischemia. When superoxide was visualized with ethidium, signals for ATF-4 and superoxide overlapped in the same cells. Moreover, lipids in the ER were robustly peroxidized by ischemia but were attenuated in transgenic animals. This indicates that superoxide attacked and damaged the ER, and that oxidative ER damage is implicated in ischemic neuronal cell death.

scholarly journals SHP-1 negatively regulates neuronal survival by functioning as a TrkA phosphatase

2003 ◽  
Vol 163 (5) ◽  
pp. 999-1010 ◽  
Author(s):  
H. Nicholas Marsh ◽  
Catherine I. Dubreuil ◽  
Celia Quevedo ◽  
Anna Lee ◽  
Marta Majdan ◽  
...  
Keyword(s):  
Cell Death ◽  
Sympathetic Neurons ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Wild Type ◽  
Naturally Occurring ◽  
Ngf Receptor ◽  
Induced Apoptosis ◽  
Developmental Cell Death ◽  
Better Than

Nerve growth factor (NGF) mediates the survival and differentiation of neurons by stimulating the tyrosine kinase activity of the TrkA/NGF receptor. Here, we identify SHP-1 as a phosphotyrosine phosphatase that negatively regulates TrkA. SHP-1 formed complexes with TrkA at Y490, and dephosphorylated it at Y674/675. Expression of SHP-1 in sympathetic neurons induced apoptosis and TrkA dephosphorylation. Conversely, inhibition of endogenous SHP-1 with a dominant-inhibitory mutant stimulated basal tyrosine phosphorylation of TrkA, thereby promoting NGF-independent survival and causing sustained and elevated TrkA activation in the presence of NGF. Mice lacking SHP-1 had increased numbers of sympathetic neurons during the period of naturally occurring neuronal cell death, and when cultured, these neurons survived better than wild-type neurons in the absence of NGF. These data indicate that SHP-1 can function as a TrkA phosphatase, controlling both the basal and NGF-regulated level of TrkA activity in neurons, and suggest that SHP-1 regulates neuron number during the developmental cell death period by directly regulating TrkA activity.

scholarly journals Lipocalin-2 Deficiency Reduces Oxidative Stress and Neuroinflammation and Results in Attenuation of Kainic Acid-Induced Hippocampal Cell Death

Antioxidants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 100
Author(s):  
Hyun Joo Shin ◽  
Eun Ae Jeong ◽  
Jong Youl Lee ◽  
Hyeong Seok An ◽  
Hye Min Jang ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Death ◽  
Kainic Acid ◽  
Neuronal Cell Death ◽  
Neuronal Cell ◽  
Lipocalin 2 ◽  
Wild Type ◽  
Iron Trafficking ◽  
Hippocampal Cell ◽  
And Oxidative Stress

The hippocampal cell death that follows kainic acid (KA)-induced seizures is associated with blood–brain barrier (BBB) leakage and oxidative stress. Lipocalin-2 (LCN2) is an iron-trafficking protein which contributes to both oxidative stress and inflammation. However, LCN2′s role in KA-induced hippocampal cell death is not clear. Here, we examine the effect of blocking LCN2 genetically on neuroinflammation and oxidative stress in KA-induced neuronal death. LCN2 deficiency reduced neuronal cell death and BBB leakage in the KA-treated hippocampus. In addition to LCN2 upregulation in the KA-treated hippocampus, circulating LCN2 levels were significantly increased in KA-treated wild-type (WT) mice. In LCN2 knockout mice, we found that the expressions of neutrophil markers myeloperoxidase and neutrophil elastase were decreased compared to their expressions in WT mice following KA treatment. Furthermore, LCN2 deficiency also attenuated KA-induced iron overload and oxidative stress in the hippocampus. These findings indicate that LCN2 may play an important role in iron-related oxidative stress and neuroinflammation in KA-induced hippocampal cell death.

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