Proteasomal dysfunction activates the transcription factor SKN-1 and produces a selective oxidative-stress response in Caenorhabditis elegans

2007 ◽  
Vol 409 (1) ◽  
pp. 205-213 ◽  
Author(s):  
Nate W. Kahn ◽  
Shane L. Rea ◽  
Sarah Moyle ◽  
Alison Kell ◽  
Thomas E. Johnson
Keyword(s):  
Oxidative Stress ◽  
Caenorhabditis Elegans ◽  
Stress Response ◽  
Nuclear Localization ◽  
Glutathione Transferase ◽  
Fluorescent Protein ◽  
Oxidative Stress Response ◽  
Specific Gene ◽  
Related Factor ◽  
Green Fluorescent

SKN-1 in the nematode worm Caenorhabditis elegans is functionally orthologous to mammalian NRF2 [NF-E2 (nuclear factor-E2)-related factor 2], a protein regulating response to oxidative stress. We have examined both the expression and activity of SKN-1 in response to a variety of oxidative stressors and to down-regulation of specific gene targets by RNAi (RNA interference). We used an SKN-1–GFP (green fluorescent protein) translational fusion to record changes in both skn-1 expression and SKN-1 nuclear localization, and a gst-4–GFP transcriptional fusion to measure SKN-1 transcriptional activity. GST-4 (glutathione transferase-4) is involved in the Phase II oxidative stress response and its expression is lost in an skn-1(zu67) mutant. In the present study, we show that the regulation of skn-1 is tied to the protein-degradation machinery of the cell. RNAi-targeted removal of most proteasome subunits in C. elegans caused nuclear localization of SKN-1 and, in some cases, induced transcription of gst-4. Most intriguingly, RNAi knockdown of proteasome core subunits caused nuclear localization of SKN-1 and induced gst-4, whereas RNAi knockdown of proteasome regulatory subunits resulted in nuclear localization of SKN-1 but did not induce gst-4. RNAi knockdown of ubiquitin-specific hydrolases and chaperonin components also caused nuclear localization of SKN-1 and, in some cases, also induced gst-4 transcription. skn-1 activation by proteasome dysfunction could be occurring by one or several mechanisms: (i) the reduced processivity of dysfunctional proteasomes may allow oxidatively damaged by-products to build up, which, in turn, activate the skn-1 stress response; (ii) dysfunctional proteasomes may activate the skn-1 stress response by blocking the constitutive turnover of SKN-1; and (iii) dysfunctional proteasomes may activate an unidentified signalling pathway that feeds back to control the skn-1 stress response.

Smooth muscle cell-specific transcription is regulated by nuclear localization of the myocardin-related transcription factors

2007 ◽  
Vol 292 (2) ◽  
pp. H1170-H1180 ◽  
Author(s):  
Jeremiah S. Hinson ◽  
Matthew D. Medlin ◽  
Kashelle Lockman ◽  
Joan M. Taylor ◽  
Christopher P. Mack
Keyword(s):  
Smooth Muscle ◽  
Transcription Factors ◽  
Nuclear Localization ◽  
Transforming Growth Factor ◽  
Serum Response Factor ◽  
Fluorescent Protein ◽  
Nuclear Translocation ◽  
Dominant Negative ◽  
Specific Gene ◽  
Green Fluorescent

On the basis of our previous studies on RhoA signaling in smooth muscle cells (SMC), we hypothesized that RhoA-mediated nuclear translocalization of the myocardin-related transcription factors (MRTFs) was important for regulating SMC phenotype. MRTF-A protein and MRTF-B message were detected in aortic SMC and in many adult mouse organs that contain a large SMC component. Both MRTFs upregulated SMC-specific promoter activity as well as endogenous SM22α expression in multipotential 10T1/2 cells, although to a lesser extent than myocardin. We used enhanced green fluorescent protein (EGFP) fusion proteins to demonstrate that the myocardin factors have dramatically different localization patterns and that the stimulation of SMC-specific transcription by certain RhoA-dependent agonists was likely mediated by increased nuclear translocation of the MRTFs. Importantly, a dominant-negative form of MRTF-A (ΔB1/B2) that traps endogenous MRTFs in the cytoplasm inhibited the SM α-actin, SM22α, and SM myosin heavy chain promoters in SMC and attenuated the effects of sphingosine 1-phosphate and transforming growth factor (TGF)-β on SMC-specific transcription. Our data confirmed the importance of the NH2-terminal RPEL domains for regulating MRTF localization, but our analysis of MRTF-A/myocardin chimeras and myocardin RPEL2 mutations indicated that the myocardin B1/B2 region can override this signal. Gel shift assays demonstrated that myocardin factor activity correlated well with ternary complex formation at the SM α-actin CArGs and that MRTF-serum response factor interactions were partially dependent on CArG sequence. Taken together, our results indicate that the MRTFs regulate SMC-specific gene expression in at least some SMC subtypes and that regulation of MRTF nuclear localization may be important for the effects of selected agonists on SMC phenotype.

scholarly journals GSK-3β, a double-edged sword in Nrf2 regulation: Implications for neurological dysfunction and disease

F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1043 ◽  
Author(s):  
Megan Culbreth ◽  
Michael Aschner
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Glycogen Synthase ◽  
Oxidative Stress Response ◽  
Neurological Dysfunction ◽  
Related Factor ◽  
Disease Etiology ◽  
Disease States ◽  
Attractive Therapeutic Target ◽  
Gsk 3Β

In the past decade, it has become evident that glycogen synthase kinase 3β (GSK-3β) modulates the nuclear factor erythroid 2-related factor 2 (Nrf2) oxidative stress response. GSK-3β functions as an inhibitor, both directly in the activation and indirectly in the post-induction of Nrf2. The incidence of oxidative stress in neurological dysfunction and disease has made this signaling pathway an attractive therapeutic target. There is minimal evidence, however, to support a distinctive function for GSK-3β mediated Nrf2 inhibition in nervous system decline, apart from the typical oxidative stress response. In both Alzheimer’s disease and brain ischemia, this pathway has been explored for potential benefits on disease etiology and advancement. Presently, it is unclear whether GSK-3β mediated Nrf2 inhibition markedly influences these disease states. Furthermore, the potential that each has unique function in neurodegenerative decline is unsubstantiated.

scholarly journals The Caenorhabditis elegans Oxidative Stress Response Requires the NHR-49 Transcription Factor

2018 ◽  
pp. g3.200727.2018 ◽  
Author(s):  
Queenie Hu ◽  
Dayana R. D'Amora ◽  
Lesley T. MacNeil ◽  
Albertha J. M. Walhout ◽  
Terrance J. Kubiseski
Keyword(s):  
Oxidative Stress ◽  
Transcription Factor ◽  
Caenorhabditis Elegans ◽  
Stress Response ◽  
Oxidative Stress Response

scholarly journals Niche-Specific Activation of the Oxidative Stress Response by the Pathogenic Fungus Candida albicans

2007 ◽  
Vol 75 (5) ◽  
pp. 2143-2151 ◽  
Author(s):  
Brice Enjalbert ◽  
Donna M. MacCallum ◽  
Frank C. Odds ◽  
Alistair J. P. Brown
Keyword(s):  
Oxidative Stress ◽  
Candida Albicans ◽  
Stress Response ◽  
Fluorescent Protein ◽  
Ex Vivo ◽  
Pathogenic Fungus ◽  
Systemic Infection ◽  
Oxidative Stress Response ◽  
Mammalian Host ◽  
Phagocytic Cells

ABSTRACT Candida albicans is a major opportunistic pathogen of humans. The pathogenicity of this fungus depends upon its ability to deal effectively with the host defenses and, in particular, the oxidative burst of phagocytic cells. We have explored the activation of the oxidative stress response in C. albicans in ex vivo infection models and during systemic infection of a mammalian host. We have generated C. albicans strains that contain specific green fluorescent protein (GFP) promoter fusions and hence act as biosensors of environmental oxidative stress at the single-cell level. Having confirmed that CTA1-, TRX1-, and TTR1/GRX2-GFP reporters respond specifically to oxidative stress, and not to heat shock, nitrosative, or osmotic stresses, we used these reporters to show that individual C. albicans cells activate an oxidative stress response following phagocytosis by neutrophils, but not by macrophages. Significantly, only a small proportion of C. albicans cells (about 4%) activated an oxidative stress response during systemic infection of the mouse kidney. The response of these cells was generally equivalent to exposure to 0.4 mM hydrogen peroxide in vitro. We conclude that most C. albicans cells are exposed to an oxidative stress when they come into contact with neutrophils in the bloodstream of the host but that oxidative killing is no longer a significant threat once an infection has been established in the kidney.

scholarly journals The Role of Nuclear Factor-E2-Related Factor 1 in the Oxidative Stress Response in MC3T3-E1 Osteoblastic Cells

2016 ◽  
Vol 31 (2) ◽  
pp. 336 ◽  
Author(s):  
So Young Park ◽  
Sung Hoon Kim ◽  
Hyun Koo Yoon ◽  
Chang Hoon Yim ◽  
Sung-Kil Lim
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Oxidative Stress Response ◽  
Osteoblastic Cells ◽  
Related Factor ◽  
Nuclear Factor

scholarly journals Upregulation of Anti-Oxidative Stress Response Improves Metabolic Changes in L-Selectin-Deficient Mice but Does Not Prevent NAFLD Progression or Fecal Microbiota Shifts

2021 ◽  
Vol 22 (14) ◽  
pp. 7314
Author(s):  
Sreepradha Eswaran ◽  
Anshu Babbar ◽  
Hannah K. Drescher ◽  
Thomas C. A. Hitch ◽  
Thomas Clavel ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Adipose Tissue ◽  
Stress Response ◽  
Immune Cell ◽  
Fecal Microbiota ◽  
Oxidative Stress Response ◽  
Metabolic Changes ◽  
Related Factor ◽  
Alcoholic Fatty Liver ◽  
Deficient Mice

(1) Background: Non-alcoholic fatty liver disease (NAFLD) is a growing global health problem. NAFLD progression involves a complex interplay of imbalanced inflammatory cell populations and inflammatory signals such as reactive oxygen species and cytokines. These signals can derive from the liver itself but also from adipose tissue or be mediated via changes in the gut microbiome. We analyzed the effects of a simultaneous migration blockade caused by L-selectin-deficiency and an enhancement of the anti-oxidative stress response triggered by hepatocytic Kelch-like ECH-associated protein 1 (Keap1) deletion on NAFLD progression. (2) Methods: L-selectin-deficient mice (Lsel−/−Keap1flx/flx) and littermates with selective hepatic Keap1 deletion (Lsel−/−Keap1Δhepa) were compared in a 24-week Western-style diet (WD) model. (3) Results: Lsel−/−Keap1Δhepa mice exhibited increased expression of erythroid 2-related factor 2 (Nrf2) target genes in the liver, decreased body weight, reduced epidydimal white adipose tissue with decreased immune cell frequencies, and improved glucose response when compared to their Lsel−/−Keap1flx/flx littermates. Although WD feeding caused drastic changes in fecal microbiota profiles with decreased microbial diversity, no genotype-dependent shifts were observed. (4) Conclusions: Upregulation of the anti-oxidative stress response improves metabolic changes in L-selectin-deficient mice but does not prevent NAFLD progression and shifts in the gut microbiota.

scholarly journals miR-148b Functions as a Tumor Suppressor by Targeting Endoplasmic Reticulum Metallo Protease 1 in Human Endometrial Cancer Cells

2018 ◽  
Vol 27 (1) ◽  
pp. 81-88 ◽  
Author(s):  
Jinfeng Qu ◽  
Lei Zhang ◽  
Lanyu Li ◽  
Yujie Su
Keyword(s):  
Oxidative Stress ◽  
Cell Proliferation ◽  
Endoplasmic Reticulum ◽  
Endometrial Cancer ◽  
Stress Response ◽  
Western Blot ◽  
Cancer Cells ◽  
Oxidative Stress Response ◽  
Luciferase Reporter ◽  
Related Factor

This study investigated the tumor-suppressive role of miR-148b in regulating endoplasmic reticulum metalloprotease 1 (ERMP1) expression and the oxidative stress response in endometrial cancer cells. Human endometrial cancer RL95-2 cells were used and transfected with miR-148b mimic, miR-148b inhibitor, or their scrambled negative control. Thereafter, the transfection efficiency was determined by RT-qPCR, and cell proliferation was assessed by MTT assay. The dual-luciferase reporter assay, Western blot, and RT-qPCR were conducted to determine the target gene of miR-148b. ERMP1 is a putative target of miR-148b, and thereby the overexpression and downregulation of ERMP1 on the proliferation of RL95-2 cells were assessed. Next, the expressions of hypoxia-inducible factor 1 (HIF-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) were analyzed by Western blot. Intracellular reactive oxygen species (ROS) was determined using dichlorofluorescin diacetate (DCFDA). Results showed that differential expression of miR-148b or ERMP1 was observed in normal endometrial tissues and endometrial cancerous tissues. Enhanced expression of miR-148b effectively inhibited proliferation of RL95-2 cells. ERMP1 was the target of miR-148b. ERMP1 silencing obviously suppressed proliferation of RL95-2 cells. Thus, miR-148b repressed cell proliferation, likely through downregulating ERMP1. Furthermore, it was observed that miR-148b significantly decreased expression of HIF-1 and Nrf2 by downregulating ERMP1. The intracellular ROS level was enhanced by miR-148b via downregulating ERMP1. To conclude, our results suggested that miR-148b suppressed cell proliferation and regulated the oxidative stress response in human endometrial cancer RL95-2 cells by inhibiting ERMP1.

scholarly journals Nrf2, the Major Regulator of the Cellular Oxidative Stress Response, is Partially Disordered

2021 ◽  
Vol 22 (14) ◽  
pp. 7434
Author(s):  
Nadun C. Karunatilleke ◽  
Courtney S. Fast ◽  
Vy Ngo ◽  
Anne Brickenden ◽  
Martin L. Duennwald ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stress Response ◽  
Cellular Response ◽  
Rational Design ◽  
Oxidative Stress Response ◽  
Full Length ◽  
Related Factor ◽  
Creb Binding Protein ◽  
Physiological Importance ◽  
Kelch Domain

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription regulator that plays a pivotal role in coordinating the cellular response to oxidative stress. Through interactions with other proteins, such as Kelch-like ECH-associated protein 1 (Keap1), CREB-binding protein (CBP), and retinoid X receptor alpha (RXRα), Nrf2 mediates the transcription of cytoprotective genes critical for removing toxicants and preventing DNA damage, thereby playing a significant role in chemoprevention. Dysregulation of Nrf2 is linked to tumorigenesis and chemoresistance, making Nrf2 a promising target for anticancer therapeutics. However, despite the physiological importance of Nrf2, the molecular details of this protein and its interactions with most of its targets remain unknown, hindering the rational design of Nrf2-targeted therapeutics. With this in mind, we used a combined bioinformatics and experimental approach to characterize the structure of full-length Nrf2 and its interaction with Keap1. Our results show that Nrf2 is partially disordered, with transiently structured elements in its Neh2, Neh7, and Neh1 domains. Moreover, interaction with the Kelch domain of Keap1 leads to protection of the binding motifs in the Neh2 domain of Nrf2, while the rest of the protein remains highly dynamic. This work represents the first detailed structural characterization of full-length Nrf2 and provides valuable insights into the molecular basis of Nrf2 activity modulation in oxidative stress response.

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