scholarly journals Nuclear Factor-Erythroid 2-Related Factor 2 (Nrf2) and Mitochondrial Dynamics/Mitophagy in Neurological Diseases

Antioxidants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 617 ◽  
Author(s):  
Tae-Cheon Kang

Mitochondria play an essential role in bioenergetics and respiratory functions for cell viability through numerous biochemical processes. To maintain mitochondria quality control and homeostasis, mitochondrial morphologies change rapidly in response to external insults and changes in metabolic status through fusion and fission (so called mitochondrial dynamics). Furthermore, damaged mitochondria are removed via a selective autophagosomal process, referred to as mitophagy. Although mitochondria are one of the sources of reactive oxygen species (ROS), they are themselves vulnerable to oxidative stress. Thus, endogenous antioxidant defense systems play an important role in cell survival under physiological and pathological conditions. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a redox-sensitive transcription factor that maintains redox homeostasis by regulating antioxidant-response element (ARE)-dependent transcription and the expression of antioxidant defense enzymes. Although the Nrf2 system is positively associated with mitochondrial biogenesis and mitochondrial quality control, the relationship between Nrf2 signaling and mitochondrial dynamics/mitophagy has not been sufficiently addressed in the literature. This review article describes recent clinical and experimental observations on the relationship between Nrf2 and mitochondrial dynamics/mitophagy in various neurological diseases.

2018 ◽  
Vol 314 (5) ◽  
pp. H928-H939 ◽  
Author(s):  
Changhai Tian ◽  
Lie Gao ◽  
Matthew C. Zimmerman ◽  
Irving H. Zucker

The imbalance between the synthesis of reactive oxygen species and their elimination by antioxidant defense systems results in macromolecular damage and disruption of cellular redox signaling, affecting cardiac structure and function, thus contributing to contractile dysfunction, myocardial hypertrophy, and fibrosis in chronic heart failure [chronic heart failure (CHF)]. The Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2 (Nrf2) pathway is an important antioxidant defense mechanism and is closely associated with oxidative stress-mediated cardiac remodeling in CHF. In the present study, we investigated the regulation of myocardial Nrf2 in the postmyocardial infarction (post-MI) state. Six weeks post-MI, Nrf2 protein was downregulated in the heart, resulting in a decrease of Nrf2-targeted antioxidant enzymes, whereas paradoxically the transcription of Nrf2 was increased, suggesting that translational inhibition of Nrf2 may contribute to the dysregulation in CHF. We therefore hypothesized that microRNAs may be involved in the translational repression of Nrf2 mRNA in the setting of CHF. Using quantitative real-time PCR analysis, we found that three microRNAs, including microRNA-27a, microRNA-28-3p, and microRNA-34a, were highly expressed in the left ventricle of infarcted hearts compared with other organs. Furthermore, in vitro analysis revealed that cultured cardiac myocytes and fibroblasts expressed these three microRNAs in response to TNF-α stimulation. These microRNAs were preferentially incorporated into exosomes and secreted into the extracellular space in which microRNA-enriched exosomes mediated intercellular communication and Nrf2 dysregulation. Taken together, these results suggest that increased local microRNAs induced by MI may contribute to oxidative stress by the inhibition of Nrf2 translation in CHF. NEW & NOTEWORTHY The results of this work provide a novel mechanism mediated by microRNA-enriched exosomes, contributing to the nuclear factor erythroid 2-related factor 2 dysregulation and subsequent oxidative stress. Importantly, these new findings will provide a promising strategy to improve the therapeutic efficacy through targeting nuclear factor erythroid 2-related factor 2-related microRNAs in the chronic heart failure state, which show potentially clinical applications.


2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Tzu-Yu Weng ◽  
Denise T. Hung ◽  
Tsung-Ping Su ◽  
Shang-Yi A. Tsai

Sigma-1 receptor (Sig-1R) functions as a chaperon that interacts with multiple proteins and lipids and is implicated in neurodegenerative and psychiatric diseases. Here, we used Sig-1R KO mice to examine brain expression profiles of astrocytes and ubiquitinated proteins, which are both hallmarks of central nervous system (CNS) pathologies. Our results showed that Sig-1R KO induces increased glial fibrillary acidic protein (GFAP) expression in primary neuron-glia cultures and in the whole brain of fetus mice with concomitantly increased accumulations of ubiquitinated proteins. Astrogliosis was also observed in the neuron-glia culture. Upon proteasome or autophagy inhibitor treatments, the pronounced ubiquitinated proteins were further increased in Sig-1R KO neurons, indicating that the Sig-1R regulates both protein degradation and quality control systems. We found that Nrf2 (nuclear factor erythroid 2-related factor 2), which functions to overcome the stress condition, was enhanced in the Sig-1R KO systems especially when cells were under stressful conditions. Mutation or deficiency of Sig-1Rs has been observed in neurodegenerative models. Our study identifies the critical roles of Sig-1R in CNS homeostasis and supports the idea that functional complementation pathways are triggered in the Sig-1R KO pathology.


2019 ◽  
Vol 30 (15) ◽  
pp. 1831-1848 ◽  
Author(s):  
Lin An ◽  
Li-Ying Peng ◽  
Ning-Yuan Sun ◽  
Yi-Lin Yang ◽  
Xiao-Wei Zhang ◽  
...  

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 758
Author(s):  
Kyung-Soo Chun ◽  
Do-Hee Kim ◽  
Young-Joon Surh

Redox homeostasis is not only essential for the maintenance of normal physiological functions, but also plays an important role in the growth, survival, and therapy resistance of cancer cells. Altered redox balance and consequent disruption of redox signaling are implicated in the proliferation and progression of cancer cells and their resistance to chemo- and radiotherapy. The nuclear factor erythroid 2 p45-related factor (Nrf2) is the principal stress-responsive transcription factor that plays a pivotal role in maintaining cellular redox homeostasis. Aberrant Nrf2 overactivation has been observed in many cancerous and transformed cells. Uncontrolled amplification of Nrf2-mediated antioxidant signaling results in reductive stress. Some metabolic pathways altered due to reductive stress have been identified as major contributors to tumorigenesis. This review highlights the multifaceted role of reductive stress in cancer development and progression.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yuanyuan Liu ◽  
Boxi Zhang ◽  
Jiahe Liu ◽  
Chunyu Qiao ◽  
Nianyu Xue ◽  
...  

As innate immune effector cells in the central nervous system (CNS), microglia not only are essential for the normal development of nervous system but also act on different neurological diseases, including Alzheimer’s disease (AD), Huntington's disease (HD), and other neuroinflammatory diseases. Mogroside V (Mog), a natural plant active ingredient and isolated form of Momordica grosvenori, has been shown to possess anti-inflammatory action, but few studies were carried out to investigate the effects of Mog on neuroinflammation. This study aimed to investigate the role of Mog in lipopolysaccharide- (LPS-) induced neuroinflammation and neuronal damage, revealing the underlying mechanisms. Our data indicated that Mog significantly inhibited the LPS-induced production of proinflammatory factors, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-18, IL-6, cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS), and high mobility group box 1 (HMGB1) in BV-2 cells. We found that Mog also suppressed toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), the phosphorylation of mitogen-activated protein kinases (MAPKs), adenosine 5′-monophosphate- (AMP-) activated protein kinase (AMPK), nuclear factor kappa-B (NF-κB), and protein kinase B (AKT). Moreover, Mog also enhanced the expression of γ-glutamyl cysteine synthetase catalytic subunit (GCLC), modifier subunit (GCLM), heme oxygenase-1 (HO-1), and quinine oxidoreductase 1 (NQO1) proteins, mostly depending on the nuclear translation of nuclear factor erythroid-2 related factor 2 (Nrf2). In contrast, pretreatment with inhibitors of AKT can suppress the phosphorylation of AMPK, Nrf2, and its downstream proteins expression. In summary, Mog might play a protective role against LPS-induced neurotoxicity by inhibiting the TLR4-MyD88 and activation of AMPK/AKT-Nrf2 signaling pathway.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Larissa Daniele Bobermin ◽  
André Quincozes-Santos ◽  
Camila Leite Santos ◽  
Ana Paula M. Varela ◽  
Thais F. Teixeira ◽  
...  

AbstractZika virus (ZIKV) infection during pregnancy was associated with microcephaly in neonates, but clinical and experimental evidence indicate that ZIKV also causes neurological complications in adults. However, the changes in neuron-glial communication, which is essential for brain homeostasis, are still unknown. Here, we report that hippocampal slices from adult rats exposed acutely to ZIKV showed significant cellular alterations regarding to redox homeostasis, inflammatory process, neurotrophic functions and molecular signalling pathways associated with neurons and glial cells. Our findings support the hypothesis that ZIKV is highly neurotropic and its infection readily induces an inflammatory response, characterized by an increased expression and/or release of pro-inflammatory cytokines. We also observed changes in neural parameters, such as adenosine receptor A2a expression, as well as in the release of brain-derived neurotrophic factor and neuron-specific enolase, indicating plasticity synaptic impairment/neuronal damage. In addition, ZIKV induced a glial commitment, with alterations in specific and functional parameters such as aquaporin 4 expression, S100B secretion and glutathione synthesis. ZIKV also induced p21 senescence-associated gene expression, indicating that ZIKV may induce early senescence. Taken together, our results indicate that ZIKV-induced neuroinflammation, involving nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor κB (NFκB) pathways, affects important aspects of neuron-glia communication. Therefore, although ZIKV infection is transient, long-term consequences might be associated with neurological and/or neurodegenerative diseases.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 375
Author(s):  
Hai Jia ◽  
Yunchang Zhang ◽  
Xuemeng Si ◽  
Yuhang Jin ◽  
Da Jiang ◽  
...  

Oxidative stress has been implicated in the etiology of multiple gastrointestinal disorders, such as irritable bowel syndrome and inflammatory bowel disease. This study was conducted to evaluate effects of natural product quercetin on diquat-induced oxidative stress in porcine enterocytes and underlying mechanisms. Intestinal porcine epithelial cell line 1 (IPEC-1) cells pretreated with or without quercetin (5 μM, 24 h) were incubated with vehicle or diquat (100 μM) for 6 h. The results showed that diquat treatment induced apoptosis in a caspase-3-dependent manner, as accompanied by elevated reactive oxygen species (ROS) production, increased mitochondrial depolarization, and reduced the abundance of tight junction proteins. These adverse effects of diquat were remarkably abrogated by quercetin administration. Further study indicated that the protective effect of quercetin was associated with elevated protein abundance of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased intracellular glutathione (GSH) content. Interestingly, the beneficial effects of quercetin on diquat-induced oxidative damage were abolished by all-trans-retinoic acid (Atra), a specific inhibitor of Nrf2, indicating a Nrf2-dependent regulation manner. The results show that quercetin attenuates diquat-induced cell injury by promoting protein abundance of Nrf2 and regulating GSH-related redox homeostasis in enterocytes. These findings provide new insights into a function role of quercetin in maintaining intestinal homeostasis.


Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 158
Author(s):  
Susana Cardoso ◽  
Icíar López ◽  
Sergio Piñeiro-Hermida ◽  
José Pichel ◽  
Paula Moreira

Insulin-like growth factor 1 receptor (IGF1R)-mediated signaling pathways modulate important neurophysiological aspects in the central nervous system, including neurogenesis, synaptic plasticity and complex cognitive functions. In the present study, we intended to characterize the impact of IGF1R deficiency in the brain, focusing on PI3K/Akt and MAPK/ERK1/2 signaling pathways and mitochondria-related parameters. For this purpose, we used 13-week-old UBC-CreERT2; Igf1rfl/fl male mice in which Igf1r was conditionally deleted. IGF1R deficiency caused a decrease in brain weight as well as the activation of the IR/PI3K/Akt and inhibition of the MAPK/ERK1/2/CREB signaling pathways. Despite no alterations in the activity of caspases 3 and 9, a significant alteration in phosphorylated GSK3β and an increase in phosphorylated Tau protein levels were observed. In addition, significant disturbances in mitochondrial dynamics and content and altered activity of the mitochondrial respiratory chain complexes were noticed. An increase in oxidative stress, characterized by decreased nuclear factor E2-related factor 2 (NRF2) protein levels and aconitase activity and increased H2O2 levels were also found in the brain of IGF1R-deficient mice. Overall, our observations confirm the complexity of IGF1R in mediating brain signaling responses and suggest that its deficiency negatively impacts brain cells homeostasis and survival by affecting mitochondria and redox homeostasis.


2021 ◽  
Vol 15 ◽  
Author(s):  
Bianca Seminotti ◽  
Mateus Grings ◽  
Paolo Tucci ◽  
Guilhian Leipnitz ◽  
Luciano Saso

Inherited metabolic disorders (IMDs) are rare genetic conditions that affect multiple organs, predominantly the central nervous system. Since treatment for a large number of IMDs is limited, there is an urgent need to find novel therapeutical targets. Nuclear factor erythroid-related factor 2 (Nrf2) is a transcription factor that has a key role in controlling the intracellular redox environment by regulating the expression of antioxidant enzymes and several important genes related to redox homeostasis. Considering that oxidative stress along with antioxidant system alterations is a mechanism involved in the neuropathophysiology of many IMDs, this review focuses on the current knowledge about Nrf2 signaling dysregulation observed in this group of disorders characterized by neurological dysfunction. We review here Nrf2 signaling alterations observed in X-linked adrenoleukodystrophy, glutaric acidemia type I, hyperhomocysteinemia, and Friedreich’s ataxia. Additionally, beneficial effects of different Nrf2 activators are shown, identifying a promising target for treatment of patients with these disorders. We expect that this article stimulates research into the investigation of Nrf2 pathway involvement in IMDs and the use of potential pharmacological modulators of this transcription factor to counteract oxidative stress and exert neuroprotection.


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