NRF2 pathway activation by KEAP1 inhibition attenuates the manifestation of aging phenotypes in salivary glands

Abstract Obesity is associated with type 2 diabetes, cardiovascular disease and increased incidence of cancer. Chronic inflammation, mainly emanating from adipose tissue, has been proposed to be one of the links between obesity and these pathologies. Thus, identification of new targets against obesity and especially obesity-induced inflammation is needed urgently. Transcription factor Nrf2 (NF-E2-related-factor-2) plays a central role in cytoprotective responses to oxidative and electrophilic stresses and also exerts anti-inflammatory effects in rodent models of inflammation. However, whether activation of Nrf2 signaling pathway influences obesity-associated inflammation in adipose tissue is not well established. To this end, we generated mice with systemic activation of the Nrf2 pathway (Keap1flox/–), as well as mouse models with tissue-specific Nrf2 pathway activation: adipocyte-specific (Fabp4Cre::Keap1flox/ flox) and myeloid cell-specific (LymCre::Keap1flox/ flox). These mice were exposed to a high-fat diet (HFD) 60% kcal fat regimen for 6-weeks or crossed into the db/db background. Keap1flox/– mice showed a dramatic decrease of the numbers of F4/80-positive macrophages in white adipose tissue (WAT). Interestingly, both Fabp4Cre::Keap1flox/ flox and LymCre::Keap1flox/ flox mice showed suppression of F4/80-positive macrophages in WAT as well, suggesting enhanced Nrf2 signaling in either adipocytes or myeloid cells might contribute to anti-inflammatory effects in WAT under the stress of HFD. Transcript levels of inflammatory markers, especially macrophage F4/80 and Cd68 and the chemokine Ccl2 were decreased in the WAT from Keap1flox/– mice on the standard diet and also in the WAT of Keap1flox/– mice in the db/db background. Pharmacological activation of the Nrf2 pathway by treatment with CDDO-Im also suppressed Ccl2 expression in WAT of HFD fed mice and db/db mice. As CCL2 is a key mediator of macrophage accumulation in adipose tissue, we further studied the potential effect of Nrf2 on the transcriptional regulation of Ccl2 using 3T3-L1 preadipocyte and RAW264.7 macrophage cell lines. Treatment of both lines with the small molecule inducer of Nrf2, diethyl maleate significantly suppressed LPS-induced expression of Ccl2. Analysis using luciferase reporter assay revealed that a Nrf2 binding site in the Ccl2 5’ flanking region from -235 to +85 contributed to gene silencing of Ccl2 by activation of Nrf2. Our findings suggest that the druggable Nrf2 pathway may be an effective target to combat obesity-associated inflammation in adipose tissue and its’ concomitant metabolic disorders. Supported by AMED BINDS JP19am0101001 (MY), 19H05649 (MY), 16KK0195 (AU), NIH R35 CA197222 (TWK), JSPS OT 290125 (YY).

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ERK/Nrf2 pathway activation by caffeic acid in HepG2 cells alleviates its hepatocellular damage caused by t-butylhydroperoxide-induced oxidative stress

BMC Complementary and Alternative Medicine ◽

10.1186/s12906-019-2551-3 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 11

Author(s):

Sung-Yong Yang ◽

Min Cheol Pyo ◽

Mi-Hyun Nam ◽

Kwang-Won Lee

Keyword(s):

Oxidative Stress ◽

Caffeic Acid ◽

Hepg2 Cells ◽

Nrf2 Pathway ◽

Hepatocellular Damage ◽

Pathway Activation

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Proanthocyanidins-Mediated Nrf2 Activation Ameliorates Glucocorticoid-Induced Oxidative Stress and Mitochondrial Dysfunction in Osteoblasts

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/9102012 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Liang Chen ◽

Sun-Li Hu ◽

Jun Xie ◽

De-Yi Yan ◽

She-Ji Weng ◽

...

Keyword(s):

Oxidative Stress ◽

Mitochondrial Dysfunction ◽

Low Dose ◽

Distal Femur ◽

Therapeutic Potential ◽

Protective Effects ◽

Nrf2 Pathway ◽

Pathway Activation ◽

Nrf2 Activation ◽

Osteoblast Apoptosis

The widespread use of therapeutic glucocorticoids has increased the frequency of glucocorticoid-induced osteoporosis (GIOP). One of the potential pathological processes of GIOP is an increased level of oxidative stress and mitochondrial dysfunction, which eventually leads to osteoblast apoptosis. Proanthocyanidins (PAC) are plant-derived antioxidants that have therapeutic potential against GIOP. In our study, a low dose of PAC was nontoxic to healthy osteoblasts and restored osteogenic function in dexamethasone- (Dex-) treated osteoblasts by suppressing oxidative stress, mitochondrial dysfunction, and apoptosis. Mechanistically, PAC neutralized Dex-induced damage in the osteoblasts by activating the Nrf2 pathway, since silencing Nrf2 partly eliminated the protective effects of PAC. Furthermore, PAC injection restored bone mass and promoted the expression of Nrf2 in the distal femur of Dex-treated osteoporotic rats. In summary, PAC protect osteoblasts against Dex-induced oxidative stress and mitochondrial dysfunction via the Nrf2 pathway activation and may be a promising drug for treating GIOP.

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Activation of the NRF2 pathway in Keap1-knockdown mice attenuates progression of age-related hearing loss

npj Aging and Mechanisms of Disease ◽

10.1038/s41514-020-00053-4 ◽

2020 ◽

Vol 6 (1) ◽

Author(s):

Tetsuya Oishi ◽

Daisuke Matsumaru ◽

Nao Ota ◽

Hiroshi Kitamura ◽

Tianxiang Zhang ◽

...

Keyword(s):

Oxidative Stress ◽

Hearing Loss ◽

Target Genes ◽

Negative Regulator ◽

Nrf2 Pathway ◽

Expression Levels ◽

Age Related ◽

Pathway Activation ◽

Brainstem Response ◽

Age Related Hearing Loss

AbstractAge-related hearing loss (AHL) is a progressive sensorineural hearing loss in elderly people. Although no prevention or treatments have been established for AHL, recent studies have demonstrated that oxidative stress is closely related to pathogenesis of AHL, suggesting that suppression of oxidative stress leads to inhibition of AHL progression. NRF2 is a master transcription factor that regulates various antioxidant proteins and cytoprotection factors. To examine whether NRF2 pathway activation prevents AHL, we used Keap1-knockdown (Keap1FA/FA) mice, in which KEAP1, a negative regulator of NRF2, is decreased, resulting in the elevation of NRF2 activity. We compared 12-month-old Keap1FA/FA mice with age-matched wild-type (WT) mice in the same breeding colony. In the Keap1FA/FA mice, the expression levels of multiple NRF2 target genes were verified to be significantly higher than the expression levels of these genes in the WT mice. Histological analysis showed that cochlear degeneration at the apical and middle turns was ameliorated in the Keap1FA/FA mice. Auditory brainstem response (ABR) thresholds in the Keap1FA/FA mice were significantly lower than those in the WT mice, in particular at low–mid frequencies. Immunohistochemical detection of oxidative stress markers suggested that oxidative stress accumulation was attenuated in the Keap1FA/FA cochlea. Thus, we concluded that NRF2 pathway activation protects the cochlea from oxidative damage during aging, in particular at the apical and middle turns. KEAP1-inhibiting drugs and phytochemicals are expected to be effective in the prevention of AHL.

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Prognostic and predictive effects of a gene expression signature for NRF2 pathway activation in lung squamous cell carcinoma (SqCC).

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.7517 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. 7517-7517

Author(s):

David W. Cescon ◽

Desmond She ◽

ChangQi Zhu ◽

Shingo Sakashita ◽

Melania Pintilie ◽

...

Keyword(s):

Gene Expression ◽

Adjuvant Chemotherapy ◽

Gene Expression Signature ◽

Phase Iii ◽

Nrf2 Pathway ◽

Expression Signature ◽

Prognostic Effect ◽

Pathway Activation ◽

Somatic Alterations ◽

Mutational Activation

7517 Background: Genomic profiling of SqCC in TCGA identified somatic alterations that activate the NRF2 transcriptional program – a master regulator of the oxidative stress response – in ~35% of tumors (NFE2L2 mutations/amplifications, KEAP1 or CUL3 mutations/deletions). This pathway has been implicated in resistance to chemotherapy. To evaluate the clinical significance of this molecular subset, we developed a gene expression classifier and tested this signature as a predictor of adjuvant chemotherapy benefit with cisplatin/vinorelbine (cis/vin) in a subset of SqCC patients with microarray data from the NCIC JBR.10 Phase III clinical trial. Methods: Logistic regression (LR) and SAM analysis were independently applied to 104 TCGA SqCC cases that had both microarray gene expression and mutation data to identify genes associated with NRF2 pathway mutational status. Overlapping genes were used to define the signature, which was then tested in 3 independent SqCC datasets (62 JBR.10; 54 UHN; 129 UM) to evaluate the prognostic and predictive values of putative NRF2 pathway activation. Results: 29 genes comprising the signature were identified by overlap between LR (291 genes) and SAM (45 genes). The signature consistently separated SqCC into 2 groups in all datasets, corresponding to putatively activated and wild type (WT) NRF2 pathway tumors. No prognostic effect of the activated signature was observed in independent datasets (UHN HR 0.86, 95%CI 0.28 – 2.67; UM HR 1.43, 95%CI 0.82 – 2.48). Similarly, in JBR10, no prognostic effect was observed in the observation arm (n=24, HR 0.66, 95%CI 0.13 – 3.29). A trend toward improved survival with adjuvant chemotherapy was observed in patients with the WT signature (HR 0.34, 95%CI 0.08 – 1.78, p=0.13), but not in patients with the activated signature (HR 1.16, 95%CI 0.19 – 6.97, p=0.87; interaction p=0.18). Conclusions: A gene expression signature based on mutational activation of the NRF2 pathway may be predictive of benefit from adjuvant cis/vin in SqCC. Patients with NRF2 pathway activating somatic alterations may have reduced benefit from this therapy. Validation of this potentially "actionable" finding in additional datasets is necessary.

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