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

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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TrmB, a tRNA m7G46 methyltransferase, plays a role in hydrogen peroxide resistance and positively modulates the translation of katA and katB mRNAs in Pseudomonas aeruginosa

Nucleic Acids Research ◽

10.1093/nar/gkz702 ◽

2019 ◽

Vol 47 (17) ◽

pp. 9271-9281 ◽

Cited By ~ 5

Author(s):

Narumon Thongdee ◽

Juthamas Jaroensuk ◽

Sopapan Atichartpongkul ◽

Jurairat Chittrakanwong ◽

Kamonchanok Chooyoung ◽

...

Keyword(s):

Oxidative Stress ◽

Pseudomonas Aeruginosa ◽

Stress Response ◽

Translational Regulation ◽

Cellular Response ◽

Oxidative Stress Response ◽

Translation Efficiency ◽

Trna Modification ◽

Negative Effect

Abstract Cellular response to oxidative stress is a crucial mechanism that promotes the survival of Pseudomonas aeruginosa during infection. However, the translational regulation of oxidative stress response remains largely unknown. Here, we reveal a tRNA modification-mediated translational response to H2O2 in P. aeruginosa. We demonstrated that the P. aeruginosa trmB gene encodes a tRNA guanine (46)-N7-methyltransferase that catalyzes the formation of m7G46 in the tRNA variable loop. Twenty-three tRNA substrates of TrmB with a guanosine residue at position 46 were identified, including 11 novel tRNA substrates. We showed that loss of trmB had a strong negative effect on the translation of Phe- and Asp-enriched mRNAs. The trmB-mediated m7G modification modulated the expression of the catalase genes katA and katB, which are enriched with Phe/Asp codons at the translational level. In response to H2O2 exposure, the level of m7G modification increased, consistent with the increased translation efficiency of Phe- and Asp-enriched mRNAs. Inactivation of trmB led to decreased KatA and KatB protein abundance and decreased catalase activity, resulting in H2O2-sensitive phenotype. Taken together, our observations reveal a novel role of m7G46 tRNA modification in oxidative stress response through translational regulation of Phe- and Asp-enriched genes, such as katA and katB.

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

F1000Research ◽

10.12688/f1000research.15239.1 ◽

2018 ◽

Vol 7 ◽

pp. 1043 ◽

Cited By ~ 15

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.

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Lamin B1 controls oxidative stress responses via Oct-1

The Journal of Cell Biology ◽

10.1083/jcb.200804155 ◽

2009 ◽

Vol 184 (1) ◽

pp. 45-55 ◽

Cited By ~ 95

Author(s):

Ashraf N. Malhas ◽

Chiu Fan Lee ◽

David J. Vaux

Keyword(s):

Oxidative Stress ◽

Stress Response ◽

Stress Responses ◽

Cellular Response ◽

Nuclear Periphery ◽

Resonance Energy Transfer ◽

Resonance Energy ◽

Oxidative Stress Response ◽

Mobility Shift ◽

Lamin B1

Interaction of lamins with chromatin and transcription factors regulate transcription. Oct-1 has previously been shown to colocalize partly with B-type lamins and is essential for transcriptional regulation of oxidative stress response genes. Using sequential extraction, co-immunoprecipitation (IP), fluorescence loss in photobleaching, and fluorescence resonance energy transfer, we confirm Oct-1–lamin B1 association at the nuclear periphery and show that this association is lost in Lmnb1Δ/Δ cells. We show that several Oct-1–dependent genes, including a subset involved in oxidative stress response, are dysregulated in Lmnb1Δ/Δ cells. Electrophoretic mobility shift assay and chromatin IP reveal that Oct-1 binds to the putative octamer-binding sequences of the dysregulated genes and that this activity is increased in cells lacking functional lamin B1. Like Oct1−/− cells, Lmnb1Δ/Δ cells have elevated levels of reactive oxygen species and are more susceptible to oxidative stress. Sequestration of Oct-1 at the nuclear periphery by lamin B1 may be a mechanism by which the nuclear envelope can regulate gene expression and contribute to the cellular response to stress, development, and aging.

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

Endocrinology and Metabolism ◽

10.3803/enm.2016.31.2.336 ◽

2016 ◽

Vol 31 (2) ◽

pp. 336 ◽

Cited By ~ 5

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

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

Biochemical Journal ◽

10.1042/bj20070521 ◽

2007 ◽

Vol 409 (1) ◽

pp. 205-213 ◽

Cited By ~ 110

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.

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

International Journal of Molecular Sciences ◽

10.3390/ijms22147314 ◽

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.

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

Oncology Research Featuring Preclinical and Clinical Cancer Therapeutics ◽

10.3727/096504018x15202988139874 ◽

2018 ◽

Vol 27 (1) ◽

pp. 81-88 ◽

Cited By ~ 10

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.

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