scholarly journals Clock Protein Bmal1 and Nrf2 Cooperatively Control Aging or Oxidative Response and Redox Homeostasis by Regulating Rhythmic Expression of Prdx6

Cells ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1861 ◽  
Author(s):  
Bhavana Chhunchha ◽  
Eri Kubo ◽  
Dhirendra P. Singh
Keyword(s):  
Redox Homeostasis ◽  
Antioxidant Response ◽  
Related Factor ◽  
Antioxidant Genes ◽  
Rhythmic Expression ◽  
Circadian Control ◽  
Ros Accumulation ◽  
E Box ◽  
Direct Binding

Many disorders of aging, including blinding-diseases, are associated with deficiency of brain and muscle arnt-like protein 1 (Bmal1) and, thereby, dysregulation of antioxidant-defense pathway. However, knowledge is limited regarding the role of Bmal1 regulation of antioxidant-pathway in the eye lens/lens epithelial cells (LECs) at the molecular level. We found that, in aging human (h)LECs, a progressive decline of nuclear factor erythroid 2-related factor 2 (Nrf2)/ARE (antioxidant response element)-mediated antioxidant genes was connected to Bmal1-deficiency, leading to accumulation of reactive oxygen species (ROS) and cell-death. Bmal1-depletion disrupted Nrf2 and expression of its target antioxidant genes, like Peroxiredoxin 6 (Prdx6). DNA binding and transcription assays showed that Bmal1 controlled expression by direct binding to E-Box in Prdx6 promoter to regulate its transcription. Mutation at E-Box or ARE reduced promoter activity, while disruption of both sites diminished the activity, suggesting that both sites were required for peak Prdx6-transcription. As in aging hLECs, ROS accumulation was increased in Bmal1-deficient cells and the cells were vulnerable to death. Intriguingly, Bmal1/Nrf2/Prdx6 and PhaseII antioxidants showed rhythmic expression in mouse lenses in vivo and were reciprocally linked to ROS levels. We propose that Bmal1 is pivotal for regulating oxidative responses. Findings also reveal a circadian control of antioxidant-pathway, which is important in combating lens/LECs damage induced by aging or oxidative stress.

Targeting PPARalpha in Alzheimer's Disease

2018 ◽  
Vol 15 (4) ◽  
pp. 345-354 ◽  
Author(s):  
Barbara D'Orio ◽  
Anna Fracassi ◽  
Maria Paola Cerù ◽  
Sandra Moreno
Keyword(s):  
Oxidative Stress ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Molecular Mechanisms ◽  
Redox Homeostasis ◽  
Antioxidant Response ◽  
Peroxisome Proliferator ◽  
Prevailing Paradigm

Background: The molecular mechanisms underlying Alzheimer's disease (AD) are yet to be fully elucidated. The so-called “amyloid cascade hypothesis” has long been the prevailing paradigm for causation of disease, and is today being revisited in relation to other pathogenic pathways, such as oxidative stress, neuroinflammation and energy dysmetabolism. The peroxisome proliferator-activated receptors (PPARs) are expressed in the central nervous system (CNS) and regulate many physiological processes, such as energy metabolism, neurotransmission, redox homeostasis, autophagy and cell cycle. Among the three isotypes (α, β/δ, γ), PPARγ role is the most extensively studied, while information on α and β/δ are still scanty. However, recent in vitro and in vivo evidence point to PPARα as a promising therapeutic target in AD. Conclusion: This review provides an update on this topic, focussing on the effects of natural or synthetic agonists in modulating pathogenetic mechanisms at AD onset and during its progression. Ligandactivated PPARα inihibits amyloidogenic pathway, Tau hyperphosphorylation and neuroinflammation. Concomitantly, the receptor elicits an enzymatic antioxidant response to oxidative stress, ameliorates glucose and lipid dysmetabolism, and stimulates autophagy.

scholarly journals Evidence for a novel antioxidant function and isoform-specific regulation of the human p66Shc gene

2014 ◽  
Vol 25 (13) ◽  
pp. 2116-2127 ◽  
Author(s):  
Masaki Miyazawa ◽  
Yoshiaki Tsuji
Keyword(s):  
Stress Response ◽  
Adaptor Protein ◽  
Erythroid Differentiation ◽  
Cell Types ◽  
Antioxidant Response ◽  
Related Factor ◽  
Antioxidant Genes ◽  
Specific Regulation ◽  
And Function ◽  
Species Production

The mammalian Shc family, composed of p46, p52, and p66 isoforms, serves as an adaptor protein in cell growth and stress response. p66Shc was shown to be a negative lifespan regulator by acting as a prooxidant protein in mitochondria; however, the regulatory mechanisms of p66Shc expression and function are incompletely understood. This study provides evidence for new features of p66Shc serving as an antioxidant and critical protein in cell differentiation. Unique among the Shc family, transcription of p66Shc is activated through the antioxidant response element (ARE)–nuclear factor erythroid 2–related factor 2 (Nrf2) pathway in K562 human erythroleukemia and other cell types after treatment with hemin, an iron-containing porphyrin. Phosphorylated p66Shc at Ser-36, previously reported to be prone to mitochondrial localization, is increased by hemin treatment, but p66Shc remains exclusively in the cytoplasm. p66Shc knockdown inhibits hemin-induced erythroid differentiation, in which reactive oxygen species production and apoptosis are significantly enhanced in conjunction with suppression of other ARE-dependent antioxidant genes. Conversely, p66Shc overexpression is sufficient for inducing erythroid differentiation. Collectively these results demonstrate the isoform-specific regulation of the Shc gene by the Nrf2-ARE pathway and a new antioxidant role of p66Shc in the cytoplasm. Thus p66Shc is a bifunctional protein involved in cellular oxidative stress response and differentiation.

Abstract P317: Acute Exercise Stress and ROS Signaling: Activation of Nrf2/ARE-Dependent Antioxidant Defense Mechanisms in the Mouse Myocardium

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Corey J Miller ◽  
Kalavathy Ramachandran ◽  
Gayatri D Khanderao ◽  
Sankaranarayanan Kannan ◽  
Vasanthi Rajasekaran ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Acute Exercise ◽  
Nuclear Translocation ◽  
Ischemia Reperfusion ◽  
Antioxidant Response ◽  
Exercise Stress ◽  
Related Factor ◽  
Paramagnetic Resonance ◽  
Antioxidant Genes ◽  
Age Dependent

Background: Cellular defense mechanisms are crucial for maintaining intracellular redox state and mitigating free radical accumulation with aging. Nuclear Erythroid 2 p45 related factor-2 (Nrf2) regulates basal and inducible expression of numerous cytoprotective/antioxidant genes. We hypothesize that acute exercise will induce ROS, which triggers Nrf2/ARE signaling and promotes myocardial defense mechanisms. Methods: Age-matched wild-type (WT) and Nrf2−/− (KO) mice at 2 and >20 months were subjected to acute exercise stress (AES) and then we assessed the activation of Nrf2/ARE-dependent transcriptional mechanisms in the heart. Myocardial ROS was measured by electron paramagnetic resonance (EPR) analysis. Results: Under basal conditions, total ROS and GSH levels were identical at 2 months, whereas they were significantly impaired in Nrf2-KO when compared to Wt myocardium at ∼20 months indicating that Nrf2-deficiency is coupled with blemished redox potential. Upon AES, the young WT and KO mice exhibited oxidative stress (OS), but the WT were able compensate for the stress by increasing Nrf2 nuclear translocation and subsequent upregulation of cytoprotective genes. However, the aged (WT & KO) mice developed OS in response to AES. The degree of OS was several fold higher in the aged Nrf2-KO mice when compared with WT, suggesting an important age dependent function for Nrf2 in the myocardium. Western blot analysis revealed significant down regulation of major antioxidants (GCS, Nqo1, Ho1, catalase, G6pd and Gsr) in KO mice, while WT mice exhibited compensatory antioxidant response to the AES. Gene expression (qPCR) analysis revealed profound upregulation of major antioxidants in WT, but there was no such response occurred in KO mice after AES, suggesting Nrf2 independent mechanisms are inadequate to protect the myocardium. Conclusions: Acute exercise induces ROS and thereby activates Nrf2 in the myocardium. However, disruption of Nrf2 increases susceptibility of the myocardium to OS induced damage. Thus Nrf2 signaling might be a potential therapeutic target to protect the heart from ROS and/or age dependent ischemia/reperfusion (I/R) injury and myocardial infarction (MI).

scholarly journals Fasting Induces Hepatocellular Carcinoma Cell Apoptosis by Inhibiting SET8 Expression

2020 ◽  
Vol 2020 ◽  
pp. 1-19 ◽  
Author(s):  
Jie Qi ◽  
Xiangyuan Chen ◽  
Qichao Wu ◽  
Jing Wang ◽  
Hao Zhang ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Viability ◽  
Cell Apoptosis ◽  
Antioxidant Response ◽  
Signalling Pathway ◽  
Related Factor ◽  
Apoptosis Resistance ◽  
Cancer Proliferation

Background. Hepatocellular carcinoma (HCC) is a life-threatening cancer, and the Kelch-like ECH-associated protein 1 (Keap1)/NF-E2-related factor 2 (Nrf2)/antioxidant response element (ARE) signalling pathway plays a crucial role in apoptosis resistance in cancer cells. Fasting is reported to mediate tumour growth reduction and apoptosis. SET8 is involved in cancer proliferation, invasiveness, and migration. However, whether SET8 participates in fasting-mediated apoptosis in HCC remains unclear. Methods. We used immunohistochemical staining to analyse the expression of SET8, Keap1, and Nrf2 in HCC tissues. Cell viability, apoptosis, and cellular reactive oxygen species (ROS) were assessed, and Western blot and qPCR analyses were used to examine the expression of Keap1/Nrf2 in HCC cells under fasting, SET8 overexpression, and PGC1α overexpression conditions. Mass spectrometry, coimmunoprecipitation, and confocal microscopy were used to determine whether PGC1α interacts with SET8. In vivo experiments were performed to verify the conclusions from the in vitro experiments. Results. Our data indicate that SET8 expression is associated with poor survival in HCC patients. Both in vitro and in vivo results demonstrated that fasting decreased cell viability and downregulated expression of SET8, Nrf2, and downstream effectors of Nrf2, while it upregulated Keap1 expression, mediated ROS accumulation, and induced HCC cell apoptosis. These results were similar to what is observed in SET8-deficient cells. Furthermore, SET8 was found to interact with PGC1α, and both PGC1α and H4K20me1, a downstream target of SET8, were found to be enriched at the Keap1 promoter region. These two factors were further determined to attenuate Keap1 promoter activity. Conclusions. The results of our study demonstrate that fasting induces HCC apoptosis by inhibiting SET8 expression and that SET8 interacts with PGC1α to activate the Nrf2/ARE signalling pathway by inhibiting Keap1 expression.

scholarly journals Fasting Drives Nrf2-Related Antioxidant Response in Skeletal Muscle

2020 ◽  
Vol 21 (20) ◽  
pp. 7780
Author(s):  
Daniele Lettieri-Barbato ◽  
Giuseppina Minopoli ◽  
Rocco Caggiano ◽  
Rossella Izzo ◽  
Mariarosaria Santillo ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Energy Homeostasis ◽  
Antioxidant Response ◽  
Protective Mechanism ◽  
Related Factor ◽  
Adaptive Responses ◽  
Positive Role

A common metabolic condition for living organisms is starvation/fasting, a state that could play systemic-beneficial roles. Complex adaptive responses are activated during fasting to help the organism to maintain energy homeostasis and avoid nutrient stress. Metabolic rearrangements during fasting cause mild oxidative stress in skeletal muscle. The nuclear factor erythroid 2-related factor 2 (Nrf2) controls adaptive responses and remains the major regulator of quenching mechanisms underlying different types of stress. Here, we demonstrate a positive role of fasting as a protective mechanism against oxidative stress in skeletal muscle. In particular, by using in vivo and in vitro models of fasting, we found that typical Nrf2-dependent genes, including those controlling iron (e.g., Ho-1) and glutathione (GSH) metabolism (e.g., Gcl, Gsr) are induced along with increased levels of the glutathione peroxidase 4 (Gpx4), a GSH-dependent antioxidant enzyme. These events are associated with a significant reduction in malondialdehyde, a well-known by-product of lipid peroxidation. Our results suggest that fasting could be a valuable approach to boost the adaptive anti-oxidant responses in skeletal muscle.

scholarly journals Protective Effects and Mechanisms of Procyanidins on Parkinson’s Disease In Vivo and In Vitro

Molecules ◽  
2021 ◽  
Vol 26 (18) ◽  
pp. 5558
Author(s):  
Juan Chen ◽  
Yixuan Chen ◽  
Yangfan Zheng ◽  
Jiawen Zhao ◽  
Huilin Yu ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Pc12 Cells ◽  
Antioxidant Activities ◽  
Antioxidant Response ◽  
Related Factor ◽  
Protective Effects ◽  
Neuroprotective Effects

This research assessed the molecular mechanism of procyanidins (PCs) against neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its metabolite 1-methyl-4-phenylpyridinium (MPP+) induced Parkinson’s disease (PD) models. In vitro, PC12 cells were incubated with PCs or deprenyl for 24 h, and then exposed to 1.5 mM MPP+ for 24 h. In vivo, zebrafish larvae (AB strain) 3 days post-fertilization (dpf) were incubated with deprenyl or PCs in 400 μM MPTP for 4 days. Compared with MPP+/MPTP alone, PCs significantly improved antioxidant activities (e.g., glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT)), and decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Furthermore, PCs significantly increased nuclear Nrf2 accumulation in PC12 cells and raised the expression of NQO1, HO-1, GCLM, and GCLC in both PC12 cells and zebrafish compared to MPP+/MPTP alone. The current study shows that PCs have neuroprotective effects, activate the nuclear factor-erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway and alleviate oxidative damage in MPP+/MPTP-induced PD models.

scholarly journals Identification of PCBP1 as a Novel Modulator of Mammalian Circadian Clock

2021 ◽  
Vol 12 ◽  
Author(s):  
Yaling Wu ◽  
Haijiao Zhao ◽  
Eric Erquan Zhang ◽  
Na Liu
Keyword(s):  
Circadian Clock ◽  
Time Course ◽  
Binding Protein ◽  
Mechanistic Study ◽  
Daily Cycle ◽  
Rhythmic Expression ◽  
Circadian Expression ◽  
E Box ◽  
Cryptochrome 1

The circadian clock governs our daily cycle of behavior and physiology. Previous studies have identified a handful of core clock components and hundreds of circadian modifiers. Here, we report the discovery that poly(C)-binding protein 1 (PCBP1), displaying a circadian expression pattern, was a novel circadian clock regulator. We found that knocking down PCBP1 resulted in period shortening in human U2OS cells, and that manipulations of PCBP1 expression altered the activity of CLOCK/BMAL1 in an E-box-based reporter assay. Further mechanistic study demonstrated that this clock function of PCBP1 appears to work by enhancing the association of Cryptochrome 1 (CRY1) with the CLOCK/BMAL1 complex, thereby negatively regulating the latter’s activation. Co-immunoprecipitation of PCBP1 and core clock molecules confirmed the interactions between PCBP1 and CRY1, and a time-course qPCR assay revealed the rhythmic expression of PCBP1 in mouse hearts in vivo. Given that the RNA interference of mushroom-body expressed (mub), the poly(rC) binding protein (PCBP) homolog of Drosophila, in the clock neurons also led to a circadian phenotype in the locomotor assay, our study deemed PCBP1 a novel clock modifier whose circadian regulatory mechanism is conserved during evolution.

scholarly journals Glucocorticoid receptor signaling represses the antioxidant response by inhibiting histone acetylation mediated by the transcriptional activator NRF2

2017 ◽  
Vol 292 (18) ◽  
pp. 7519-7530 ◽  
Author(s):  
Md. Morshedul Alam ◽  
Keito Okazaki ◽  
Linh Thi Thao Nguyen ◽  
Nao Ota ◽  
Hiroshi Kitamura ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Glucocorticoid Receptor ◽  
Histone Acetylation ◽  
Transcriptional Activation ◽  
Transcriptional Activator ◽  
Antioxidant Response ◽  
Related Factor ◽  
Dependent Manner ◽  
Antioxidant Genes ◽  
Repressive Effect

NRF2 (nuclear factor erythroid 2-related factor 2) is a key transcriptional activator that mediates the inducible expression of antioxidant genes. NRF2 is normally ubiquitinated by KEAP1 (Kelch-like ECH-associated protein 1) and subsequently degraded by proteasomes. Inactivation of KEAP1 by oxidative stress or electrophilic chemicals allows NRF2 to activate transcription through binding to antioxidant response elements (AREs) and recruiting histone acetyltransferase CBP (CREB-binding protein). Whereas KEAP1-dependent regulation is a major determinant of NRF2 activity, NRF2-mediated transcriptional activation varies from context to context, suggesting that other intracellular signaling cascades may impact NRF2 function. To identify a signaling pathway that modifies NRF2 activity, we immunoprecipitated endogenous NRF2 and its interacting proteins from mouse liver and identified glucocorticoid receptor (GR) as a novel NRF2-binding partner. We found that glucocorticoids, dexamethasone and betamethasone, antagonize diethyl maleate-induced activation of NRF2 target genes in a GR-dependent manner. Dexamethasone treatment enhanced GR recruitment to AREs without affecting chromatin binding of NRF2, resulting in the inhibition of CBP recruitment and histone acetylation at AREs. This repressive effect was canceled by the addition of histone deacetylase inhibitors. Thus, GR signaling decreases NRF2 transcriptional activation through reducing the NRF2-dependent histone acetylation. Consistent with these observations, GR signaling blocked NRF2-mediated cytoprotection from oxidative stress. This study suggests that an impaired antioxidant response by NRF2 and a resulting decrease in cellular antioxidant capacity account for the side effects of glucocorticoids, providing a novel viewpoint for the pathogenesis of hypercorticosteroidism.

scholarly journals High glucose inhibits vascular endothelial Keap1/Nrf2/ARE signal pathway via downregulation of monomethyltransferase SET8 expression

2020 ◽  
Vol 52 (5) ◽  
pp. 506-516
Author(s):  
Xiangyuan Chen ◽  
Jie Qi ◽  
Qichao Wu ◽  
Hui Jiang ◽  
Jing Wang ◽  
...  
Keyword(s):  
High Glucose ◽  
Promoter Activity ◽  
Umbilical Vein ◽  
Antioxidant Response ◽  
Signal Pathway ◽  
Mechanistic Study ◽  
Related Factor ◽  
Downstream Target ◽  
Ros Accumulation ◽  
Pathway Inhibition

Abstract Hyperglycemia-mediated reactive oxygen species (ROS) accumulation plays an important role in hyperglycemia-induced endothelial injury. Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway inhibition participates in hyperglycemia-induced ROS accumulation. Our previous study indicated that SET8 overexpression inhibits high glucose-mediated ROS accumulation in human umbilical vein endothelial cells (HUVECs). In the present study, we hypothesize that SET8 may play a major role in high glucose-induced ROS accumulation via modulation of Keap1/Nrf2/ARE pathway. Our data indicated that high glucose mediated cell viability reduction, ROS accumulation, and Nrf2/ARE signal pathway inhibition via upregulation of Keap1 expression in HUVECs. Moreover, high glucose inhibited the expressions of SET8 and H4K20me1 (a downstream target of SET8). SET8 overexpression improved high glucose-mediated Keap1/Nrf2/ARE pathway inhibition and endothelial oxidation. Consistently, the effects of sh-SET8 were similar to that of high glucose treatment and were reversed by si-Keap1. A mechanistic study found that H4K20me1 was enriched at the Keap1 promoter region. SET8 overexpression attenuated Keap1 promoter activity and its expression, while mutant SET8 R259G did not affect Keap1 promoter activity and expression. The results of this study demonstrated that SET8 negatively regulates Keap1 expression, thus participating in high glucose-mediated Nrf2/ARE signal pathway inhibition and oxidative injury in HUVECs.

scholarly journals Sulforaphane-Induced Klf9/Prdx6 Axis Acts as a Molecular Switch to Control Redox Signaling and Determines Fate of Cells

Cells ◽  
2019 ◽  
Vol 8 (10) ◽  
pp. 1159 ◽  
Author(s):  
Bhavana Chhunchha ◽  
Eri Kubo ◽  
Dhirendra P. Singh
Keyword(s):  
Cell Death ◽  
Antioxidant Defense ◽  
Antioxidant Response ◽  
Therapeutic Interventions ◽  
Related Factor ◽  
Antioxidant Genes ◽  
Peroxiredoxin 6 ◽  
Dose Levels ◽  
Dose Dependent ◽  
Higher Doses

Sulforaphane (SFN), an activator of transcription factor Nrf2 (NFE2-related factor), modulates antioxidant defense by Nrf2-mediated regulation of antioxidant genes like Peroxiredoxin 6 (Prdx6) and affects cellular homeostasis. We previously observed that dose levels of SFN are crucial in determining life or death of lens epithelial cells (LECs). Herein, we demonstrated that higher doses of SFN (>6 μM) activated death signaling by overstimulation of Nrf2/ARE (antioxidant response element)-mediated Kruppel-like factor (Klf9) repression of Prdx6 expression, which increased reactive oxygen species (ROS) load and cell death. Mechanistically, Klf9 bound to its repressive Klf9 binding elements (RKBE; 5-CA/GCCC-3) in the Prdx6 promoter, and repressed Prdx6 transcription. Under the condition of higher dose of SFN, excessive Nrf2 abundance caused death signaling by enforcing Klf9 activation through ARE (5-RTGAYnnnGC-3) in Klf9 promoter that suppress antioxidant genes such as Prdx6 via a Klf9-dependent fashion. Klf9-depletion showed that Klf9 independently caused ROS reduction and subsequent cell survival, demonstrating that Klf9 upregulation caused cell death. Our work revealed the molecular mechanism of dose-dependent altered activity of SFN in LECs, and demonstrated that SFN activity was linked to levels of Nrf2/Klf9/Prdx6 axis. We proposed that in the development of therapeutic interventions for aging/oxidative disorders, combinations of Klf9-ShRNA and Nrf2 inducers may prove to be a promising strategy.

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