scholarly journals DYT-TOR1A Subcellular Proteomics Reveals Selective Vulnerability of the Nuclear Proteome to Cell Stress

2021 ◽  
Author(s):  
Kunal Shroff ◽  
Zachary F Caffall ◽  
Nicole Calakos

TorsinA is a AAA+ ATPase that shuttles between the ER lumen and outer nuclear envelope in an ATP-dependent manner and is functionally implicated in nucleocytoplasmic transport. We hypothesized that the DYT-TOR1A dystonia disease-causing variant, ΔE TorsinA, may therefore disrupt the normal subcellular distribution of proteins between the nuclear and cytosolic compartments. To test this hypothesis, we performed proteomic analysis on nuclear and cytosolic subcellular fractions from DYT-TOR1A and wildtype mouse embryonic fibroblasts (MEFs). We further examined the compartmental proteomes following exposure to thapsigargin (Tg), an endoplasmic reticulum (ER) stressor, because DYT-TOR1A dystonia models have previously shown abnormalities in cellular stress responses. Across both subcellular compartments, proteomes of DYT-TOR1A cells showed basal state disruptions consistent with an activated stress response, and in response to thapsigargin, a blunted stress response. However, the DYT-TOR1A nuclear proteome under Tg cell stress showed the most pronounced and disproportionate degree of protein disruptions - 3-fold greater than all other conditions. The affected proteins extended beyond those typically associated with stress responses, including enrichments for processes critical for neuronal synaptic function. These findings highlight the advantage of subcellular proteomics to reveal events that localize to discrete subcellular compartments and refine thinking about the mechanisms and significance of cell stress in DYT-TOR1A pathogenesis.

2018 ◽  
Author(s):  
Meirong Bai ◽  
Roman Vozdek ◽  
Aleš Hnízda ◽  
Chenxiao Jiang ◽  
Bingying Wang ◽  
...  

AbstractMesencephalic Astrocyte-Derived Neurotrophic Factor (MANF) is an endoplasmic reticulum (ER) protein that can be secreted and protect dopamine neurons and cardiomyocytes from ER stress and apoptosis. The mechanism of action of extracellular MANF has long been elusive. From a genetic screen for mutants with abnormal ER stress response, we identified the gene Y54G2A.23 as the evolutionarily conserved C. elegans MANF orthologue. We find that MANF binds to the lipid sulfatide, also known as 3-O-sulfogalactosylceramide present in serum and outer-cell membrane leaflets, directly in isolated forms and in reconstituted lipid micelles. Sulfatide binding promotes cellular MANF uptake and cytoprotection from hypoxia-induced cell death. Heightened ER stress responses of MANF-null C. elegans mutants and mammalian cells are alleviated by human MANF in a sulfatide-dependent manner. Our results demonstrate conserved roles of MANF in sulfatide binding and ER stress response, supporting sulfatide as a long-sought lipid mediator of MANF’s cytoprotection.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Liang Zhang ◽  
Lidan Zhao ◽  
Xinjie Zhang ◽  
Wei Liang ◽  
Shuping Zhang

Abstract Background Timing of breeding season of temperate passerines has been considered to be adjusted to their food availability. There is little work to reveal the cell stress responses of the nestlings hatched asynchronized with the food abundance peak, which is important for understanding the physiological link between the timing of breeding and the fitness of offspring. Methods Using gene expression level of blood HSP70 and HSP90 as indicators, we compared the cell stress response of Asian Short-toed Lark (Calandrella cheleensis) nestlings hatched under conditions of low, mid or high food (grasshopper nymph) availability in 2017. Results Nymph biomass, sample time and interaction of these two factors significantly influenced the blood gene expression level of HSP70 and HSP90 of Asian Short-toed Lark nestlings. HSP70 and HSP90 gene expression levels of the nestlings at 14:00 were significantly higher than those at 5:00. At either 5:00 or 14:00, the gene expression levels of HSP70 and HSP90 increase with the decrease of nymph biomass. Conclusions These results indicate that food availability is an important environment factor inducing cellular stress of Asian Short-toed Lark nestlings. The interactive effect of the nymph abundance and sample time on the HSPs response may be related with the daily temperature variation of the grassland. Over cell stress response may be one of physiological factor mediating the effect of food availability and the nestling’s fitness.


2021 ◽  
Author(s):  
Yi-Ju Lu ◽  
Huan Chen ◽  
Alex Corrion ◽  
Pai Li ◽  
Ilker Buyuk ◽  
...  

NON-RACE-SPECIFIC DISEASE RISISTANCE1 (NDR1) is a key component of plant immune signaling, required for defense against the bacterial pathogen Pseudomonas syringae. Plant stress responses have overlapping molecular, physiological, and cell biology signatures, and given the central role of NDR1 during biotic stress perception and signaling, we hypothesized that NDR1 also functions in abiotic stress responses, including in a role that mediates signaling at the plasma membrane (PM) - cell wall (CW) continuum. Here, we demonstrate that NDR1 is required for the induction of drought stress responses in plants, a role that couples stress signaling in an abscisic acid-dependent manner. We show that NDR1 physically associates with the PM-localized H+-ATPases AHA1, AHA2 , and AHA5 and is required for proper regulation of H+-ATPase activity and stomatal guard cell dynamics, providing a mechanistic function of NDR1 during drought responses. In the current study, we demonstrate that NDR1 functions in signaling processes associated with both biotic and abiotic stress response pathways, a function we hypothesize represents NDR1's role in the maintenance of cellular homeostasis during stress. We propose a role for NDR1 as a core transducer of signaling between cell membrane processes and intercellular stress response activation.


Author(s):  
Kirsten E. Snijders ◽  
Anita Fehér ◽  
Zsuzsanna Táncos ◽  
István Bock ◽  
Annamária Téglási ◽  
...  

AbstractTagging of endogenous stress response genes can provide valuable in vitro models for chemical safety assessment. Here, we present the generation and application of a fluorescent human induced pluripotent stem cell (hiPSC) reporter line for Heme oxygenase-1 (HMOX1), which is considered a sensitive and reliable biomarker for the oxidative stress response. CRISPR/Cas9 technology was used to insert an enhanced green fluorescent protein (eGFP) at the C-terminal end of the endogenous HMOX1 gene. Individual clones were selected and extensively characterized to confirm precise editing and retained stem cell properties. Bardoxolone-methyl (CDDO-Me) induced oxidative stress caused similarly increased expression of both the wild-type and eGFP-tagged HMOX1 at the mRNA and protein level. Fluorescently tagged hiPSC-derived proximal tubule-like, hepatocyte-like, cardiomyocyte-like and neuron-like progenies were treated with CDDO-Me (5.62–1000 nM) or diethyl maleate (5.62–1000 µM) for 24 h and 72 h. Multi-lineage oxidative stress responses were assessed through transcriptomics analysis, and HMOX1-eGFP reporter expression was carefully monitored using live-cell confocal imaging. We found that eGFP intensity increased in a dose-dependent manner with dynamics varying amongst lineages and stressors. Point of departure modelling further captured the specific lineage sensitivities towards oxidative stress. We anticipate that the newly developed HMOX1 hiPSC reporter will become a valuable tool in understanding and quantifying critical target organ cell-specific oxidative stress responses induced by (newly developed) chemical entities.


2005 ◽  
Vol 187 (10) ◽  
pp. 3359-3368 ◽  
Author(s):  
Enrique D. Vinés ◽  
Cristina L. Marolda ◽  
Aran Balachandran ◽  
Miguel A. Valvano

ABSTRACT We have previously shown that the TolA protein is required for the correct surface expression of the Escherichia coli O7 antigen lipopolysaccharide (LPS). In this work, ΔtolA and Δpal mutants of E. coli K-12 W3110 were transformed with pMF19 (encoding a rhamnosyltransferase that reconstitutes the expression of O16-specific LPS), pWQ5 (encoding the Klebsiella pneumoniae O1 LPS gene cluster), or pWQ802 (encoding the genes necessary for the synthesis of Salmonella enterica O:54). Both ΔtolA and Δpal mutants exhibited reduced surface expression of O16 LPS as compared to parental W3110, but no significant differences were observed in the expression of K. pneumoniae O1 LPS and S. enterica O:54 LPS. Therefore, TolA and Pal are required for the correct surface expression of O antigens that are assembled in a wzy (polymerase)-dependent manner (like those of E. coli O7 and O16) but not for O antigens assembled by wzy-independent pathways (like K. pneumoniae O1 and S. enterica O:54). Furthermore, we show that the reduced surface expression of O16 LPS in ΔtolA and Δpal mutants was associated with a partial defect in O-antigen polymerization and it was corrected by complementation with intact tolA and pal genes, respectively. Using derivatives of W3110ΔtolA and W3110Δpal containing lacZ reporter fusions to fkpA and degP, we also demonstrate that the RpoE-mediated extracytoplasmic stress response is upregulated in these mutants. Moreover, an altered O16 polymerization was also detected under conditions that stimulate RpoE-mediated extracytoplasmic stress responses in tol + and pal + genetic backgrounds. A Wzy derivative with an epitope tag at the C-terminal end of the protein was stable in all the mutants, ruling out stress-mediated proteolysis of Wzy. We conclude that the absence of TolA and Pal elicits a sustained extracytoplasmic stress response that in turn reduces O-antigen polymerization but does not affect the stability of the Wzy O-antigen polymerase.


2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi168-vi168
Author(s):  
Amber Jones ◽  
Kate Rochlin ◽  
Lawrence Lamb ◽  
Anita Hjelmeland

Abstract Glioblastoma (GBM) is an aggressive cancer that has been largely intractable to novel therapies, however, enhancing the efficacy of immunotherapy could potentially overcome immunosuppression and potentially improve patient outcomes. The cellular stress induced by Temozolomide (TMZ) increases innate immune ligands, which could be exploited to promote immune recognition. TMZ-induced DNA damage can activate the stress response pathway, increasing the expression of NKG2D ligands (NKG2DL) on tumor cells. This leads to an increase in NKG2DL recognition by NKG2D receptors on both natural killer and cytotoxic T-cells to elicit a cytotoxic effect. The lymphodepleting effect of TMZ, however, can limit the ability of these cells to recognize and kill tumor cells. TMZ was shown to induce NKG2DL in gliomas both in vitro and in vivo, providing the basis for clinical trials of TMZ in combination with genetically engineered TMZ-resistant gamma delta T-cells (NCT04165941). To further promote immune recognition, we sought to augment the TMZ-induced stress response by exploring the combination of DNA alkylation with either PARP (Niraparib) or ATM Kinase inhibition (AZD1390). Combinatorial therapy significantly, but heterogeneously, increased differential subsets of NKG2DL genes in comparison to TMZ alone in GBM cells isolated from patient derived xenografts (PDX): 1) MICA and MICB were increased at least 10-fold in D456 (proneural) cells; 2) ULBP1 and ULBP2 were increased at least 2-fold in JX39 (classical) cells; and 3) minimal increases in NKG2DLs were observed in JX22 (mesenchymal) cells. Repression of NKG2DLs by hypoxia/low glucose was also heterogeneous, being observed in two of three GBM models tested. We are currently determining whether these combinatorial treatments improve gamma delta T-cell cytotoxicity against GBM cells and in vivo tumor models. Taken together, our data suggest that enhancing cell stress responses induced by chemotherapies may permit novel immunotherapy therapeutic interventions for brain tumor patients.


2011 ◽  
Vol 193 (22) ◽  
pp. 6179-6186 ◽  
Author(s):  
Adam Kulp ◽  
Meta J. Kuehn

Gram-negative bacteria react to misfolded proteins in the envelope through a myriad of different stress response pathways. This cohort of pathways allows the bacteria to specifically respond to different types of damage, and many of these have been discovered to have key roles in the virulence of bacterial pathogens. Misfolded outer membrane proteins (OMPs) are typically recognized by the σEpathway, a highly conserved envelope stress response pathway. We examined the features of misfolded OMPs with respect to their ability to generate envelope stress responses. We determined that the secondary structure, particularly the potential to form β strands, is critical to inducing the σEresponse in an RseB-dependent manner. The sequence of the potential β-strand motif modulates the strength of the σEresponse generated by the constructs. By understanding the details of how such stress response pathways are activated, we can gain a greater understanding of how bacteria survive in harsh environments.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 99
Author(s):  
Shweta Devi ◽  
Vijay Kumar ◽  
Sandeep Kumar Singh ◽  
Ashish Kant Dubey ◽  
Jong-Joo Kim

Neurodegenerative disorders, such as Parkinson’s disease (PD), Alzheimer’s disease (AD), Amyotrophic lateral sclerosis (ALS), and Huntington’s disease (HD), are the most concerning disorders due to the lack of effective therapy and dramatic rise in affected cases. Although these disorders have diverse clinical manifestations, they all share a common cellular stress response. These cellular stress responses including neuroinflammation, oxidative stress, proteotoxicity, and endoplasmic reticulum (ER)-stress, which combats with stress conditions. Environmental stress/toxicity weakened the cellular stress response which results in cell damage. Small molecules, such as flavonoids, could reduce cellular stress and have gained much attention in recent years. Evidence has shown the potential use of flavonoids in several ways, such as antioxidants, anti-inflammatory, and anti-apoptotic, yet their mechanism is still elusive. This review provides an insight into the potential role of flavonoids against cellular stress response that prevent the pathogenesis of neurodegenerative disorders.


Pathogens ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 286
Author(s):  
Mary Frances Nakamya ◽  
Moses B. Ayoola ◽  
Leslie A. Shack ◽  
Mirghani Mohamed ◽  
Edwin Swiatlo ◽  
...  

Polyamines such as putrescine, cadaverine, and spermidine are small cationic molecules that play significant roles in cellular processes, including bacterial stress responses and host–pathogen interactions. Streptococcus pneumoniae is an opportunistic human pathogen, which causes several diseases that account for significant morbidity and mortality worldwide. As it transits through different host niches, S. pneumoniae is exposed to and must adapt to different types of stress in the host microenvironment. We earlier reported that S. pneumoniae TIGR4, which harbors an isogenic deletion of an arginine decarboxylase (ΔspeA), an enzyme that catalyzes the synthesis of agmatine in the polyamine synthesis pathway, has a reduced capsule. Here, we report the impact of arginine decarboxylase deletion on pneumococcal stress responses. Our results show that ΔspeA is more susceptible to oxidative, nitrosative, and acid stress compared to the wild-type strain. Gene expression analysis by qRT-PCR indicates that thiol peroxidase, a scavenger of reactive oxygen species and aguA from the arginine deiminase system, could be important for peroxide stress responses in a polyamine-dependent manner. Our results also show that speA is essential for endogenous hydrogen peroxide and glutathione production in S. pneumoniae. Taken together, our findings demonstrate the critical role of arginine decarboxylase in pneumococcal stress responses that could impact adaptation and survival in the host.


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