Nuclear Factor Erythroid 2-like 2 Research Articles

Pharmacological activation of endogenous protective pathways against oxidative stress under conditions of sepsis

BackgroundMitochondrial oxidative stress has a role in sepsis-induced organ dysfunction. The endogenous mechanisms to initiate protective pathways are controlled by peroxisome proliferator-activated receptor gamma co-activator 1-alpha (PGC1α) and nuclear factor erythroid 2-like 2 (NFE2L2). Activation of these pathways are potential therapeutic targets in sepsis. We used pharmacological activators to determine the effects on markers of mitochondrial damage and inflammation in human endothelial cells under conditions of sepsis. MethodsHuman endothelial cells were exposed to lipopolysaccharide plus peptidoglycan G to mimic a sepsis environment, with a range of concentrations of a selective synthetic agonist of silent information regulator-1 (SIRT-1) which activates PGC1α, or bis(2-hydroxy-benzylidene) acetone (2HBA) which activates NFE2L2, with and without inhibitors of these pathways. Cells were cultured for up to seven days and we measured mitochondrial membrane potential, metabolic activity, and density (as a marker of biogenesis), interkeukin-6 (to reflect inflammation) and glutathione (as a measure of antioxidant status). ResultsUnder conditions mimicking sepsis, activation of the PGC1α and NFE2L2 pathways protected cells from LPS/PepG-induced loss of mitochondrial membrane potential (P+0.0002 and P+0.0009, respectively) and metabolic activity (P+0.05 and P<0.0001, respectively), and dampened interleukin-6 responses (P+0.003 and P+0.0001, respectively). Mitochondrial biogenesis (both P+0.0001) and glutathione (both P<0.0001) were also increased. These effects were blunted by the respective inhibitors. ConclusionsThe development of organ dysfunction during human sepsis is linked to mitochondrial dysfunction, and so activation of PGC1α/NFE2L2 is likely to be beneficial. These pathways are attractive therapeutic targets for sepsis.

Common variants of NFE2L2 gene predisposes to acute respiratory distress syndrome in patients with severe sepsis.

IntroductionThe purpose of this study was to investigate whether common variants across the nuclear factor erythroid 2-like 2 (NFE2L2) gene contribute to the development of the acute respiratory distress syndrome (ARDS) in patients with severe sepsis. NFE2L2 is involved in the response to oxidative stress, and it has been shown to be associated with the development of ARDS in trauma patients.MethodsWe performed a case–control study of 321 patients fulfilling international criteria for severe sepsis and ARDS who were admitted to a Spanish network of post-surgical and critical care units, as well as 871 population-based controls. Six tagging single-nucleotide polymorphisms (SNPs) of NFE2L2 were genotyped, and, after further imputation of additional 34 SNPs, association testing with ARDS susceptibility was conducted using logistic regression analysis.ResultsAfter multiple testing adjustments, our analysis revealed 10 non-coding SNPs in tight linkage disequilibrium (0.75 ≤ r2 ≤ 1) that were associated with ARDS susceptibility as a single association signal. One of those SNPs (rs672961) was previously associated with trauma-induced ARDS and modified the promoter activity of the NFE2L2 gene, showing an odds ratio of 1.93 per T allele (95 % confidence interval, 1.17–3.18; p = 0.0089).ConclusionsOur findings support the involvement of NFE2L2 gene variants in ARDS susceptibility and reinforce further exploration of the role of oxidant stress response as a risk factor for ARDS in critically ill patients.

LAPTM4B is associated with poor prognosis in NSCLC and promotes the NRF2-mediated stress response pathway in lung cancer cells.

We recently demonstrated that lysosomal protein transmembrane 4 beta (LAPTM4B) is elevated in non-small cell lung cancers (NSCLCs) and in the surrounding premalignant airway field of cancerization. In the present study, we sought to begin to understand the relevance of LAPTM4B expression and signaling to NSCLC pathogenesis. In situ hybridization analysis of LAPTM4B transcript in tissue microarrays comprised of 368 NSCLCs demonstrated that LAPTM4B expression was significantly increased in smoker compared to non-smoker lung adenocarcinoma tumors (P < 0.001) and was significantly associated with poor overall survival (P < 0.05) in adenocarcinoma patients. Knockdown of LAPTM4B expression inhibited cell growth, induced cellular apoptosis and decreased cellular autophagy in serum starved lung cancer cells. Expression profiling coupled with pathways analysis revealed decreased activation of the nuclear factor erythroid 2-like 2 (NRF2) stress response pathway following LAPTM4B knockdown. Further analysis demonstrated that LAPTM4B augmented the expression and nuclear translocation of the NRF2 transcription factor following serum deprivation as well as increased the expression of NRF2 target genes such as heme oxygenase 1/HMOX1). Our study points to the relevance of LAPTM4B expression to NSCLC pathogenesis as well as to the probable role of LAPTM4B/NRF2 signaling in promoting lung cancer cell survival.

Effects of dietary supplementation with ferulic Acid or vitamin e individually or in combination on meat quality and antioxidant capacity of finishing pigs.

This study aimed to evaluate the effects of vitamin E (VE), ferulic acid (FA) and their combination supplementation on meat quality and antioxidant capacities of finishing pigs. Sixty barrows were randomly allocated to four experimental diets using a 2×2 factorial arrangement with 2 VE supplemental levels (0 or 400 mg/kg) and 2 FA supplemental levels (0 or 100 mg/kg) in basal diets. After 28 days, six pigs per treatment were slaughtered. The results showed that VE supplementation increased loin eye area of pigs (p<0.05) and FA supplementation increased pH45min value (p<0.05). The interaction of FA×VE was observed in shear force of longissimus dorsi muscle (p<0.05). Moreover, supplementation with VE decreased hepatic and sarcous malondialdehyde (MDA) content, increased hepatic glutathione (GSH) content and sarcous glutathione peroxidase (GSH-Px) activity (p<0.05). Additionally, supplementation with FA increased hepatic GSH-Px activity and decreased sarcous MDA content (p<0.05). However, dietary treatment did not affect the expression of genes related to nuclear factor, erythroid 2-like 2 (NFE2L2) pathway. These results suggest that dietary FA and VE could partially improve meat quality and antioxidant capacity of finishing pigs, but not by activating NFE2L2 pathway under the normal conditions of farming.

Inhibitor of differentiation proteins protect against oxidative stress by regulating the antioxidant-mitochondrial response in mouse beta cells.

Oxidative stress is implicated in beta cell glucotoxicity in type 2 diabetes. Inhibitor of differentiation (ID) proteins are transcriptional regulators induced by hyperglycaemia in islets, but the mechanisms involved and their role in beta cells are not clear. Here we investigated whether or not oxidative stress regulates ID levels in beta cells and the role of ID proteins in beta cells during oxidative stress. MIN6 cells were cultured in H2O2 or ribose to induce oxidative stress. ID1, ID3 and small MAF proteins (MAFF, MAFG and MAFK) were inhibited using small interfering RNA. Isolated islets from Id1(-/-), Id3(-/-) and diabetic db/db mice were used. ID1-4 expression was upregulated in vivo in the islets of diabetic db/db mice and stimulated in vitro by ribose and H2O2. Id1/3 inhibition reduced the expression of multiple antioxidant genes and potentiated oxidative stress-induced apoptosis. This finding was associated with increased levels of intracellular reactive oxygen species, altered mitochondrial morphology and reduced expression of Tfam, which encodes a mitochondrial transcription factor, and respiratory chain components. Id1/3 inhibition also reduced the expression of small MAF transcription factors (MafF, MafG and MafK), interacting partners of nuclear factor, erythroid 2-like 2 (NFE2L2), master regulator of the antioxidant response. Inhibition of small MAFs reduced the expression of antioxidant genes and potentiated oxidative stress-induced apoptosis, thus recapitulating the effects of Id1/3 inhibition. Our study identifies IDs as a novel family of oxidative stress-responsive proteins in beta cells. IDs are crucial regulators of the adaptive antioxidant-mitochondrial response that promotes beta cell survival during oxidative stress through a novel link to the NFE2L2-small MAF pathway.

Arsenic Trioxide Activate Transcription of Heme Oxygenase-1 by Promoting Nuclear Translocation of NFE2L2.

In a previous study, we found that induced expression of Heme Oxygenase-1 (HO-1) is responsible for the resistance of human osteosarcoma MG63 cells to the chemotherapeutic agent arsenic trioxide (ATO). The present study was aimed at investigating the molecular mechanisms underlying the induction of HO-1 that occurs after exposure of MG63 cells to ATO. First, using RT-QPCT and Western-blot, we found that ATO strongly induced the expression of heme oxygenase-1 (HO-1) in these human osteosarcoma cells. Then by analyzing HO-1 mRNA of MG63 cells exposed to ATO in the presence and absence of a transcription inhibitor Actinomycin-D (Act-D), we demonstrated that ATO activates HO-1 expression in MG63 cells by regulating the transcription of the gene. Finally, through the analysis of the NFE2L2 protein levels among the total cellular and nuclear proteins by Western-blot and Immunocytochemical staning, we determined that ATO enhanced the nuclear translocation of nuclear factor erythroid 2-like 2 (NFE2L2), also known as Nrf2. From these results we have concluded that transcription activation of HO-1 resulting from the nuclear translocation of NFE2L2 is the underlying molecular mechanism for its high induction, which, in turn, is responsible for the resistance of human osteosarcoma cells to ATO treatment.

Abstract 1597: Transcriptomic architecture of the field of cancerization in the adjacent normal-appearing airway: Early mechanisms in lung carcinogenesis

Abstract Increasing our understanding of early events in the pathogenesis of lung cancer is crucial for identification of new targets for prevention and treatment of this malignancy. Earlier work has shown that seemingly normal cells adjacent to the tumor carry specific molecular alterations that are characteristic of the tumor itself suggestive of a field of cancerization. By sampling and studying normal-appearing tissue, the molecular field of cancerization provides biological insights into early phases in cancer development. In this study, we sought to characterize molecular field effects in the normal-appearing airway that are most representative of the nearby lung tumor, and thus, are most likely to denote early events in lung carcinogenesis. To achieve this, we performed genome-wide expression profiling of resected field cancerization specimens (n=20 patients) comprised of matched early-stage non-small cell lung cancers (NSCLCs), cytologically normal airways with varying spatial distance from the tumors and distant (relative to location of tumors) normal lung tissues (n=194 samples). Using ordinal logistic regression, we identified 422 genes that were progressively modulated in expression in normal-appearing airways by spatial distance from tumors. Notably, when examined in paired NSCLC and normal lung tissues, these genes were found to recapitulate tumor expression profiles. We then sought to examine the role of lysosomal protein transmembrane 4 beta (LAPTM4B), a putative oncogene that was found to be up-regulated in airways by shorter spatial distance from tumors, in lung oncogenesis. LAPTM4B was significantly elevated in NSCLC tissues compared to paired distant normal lung and was predictive of poor survival in lung adenocarcinoma. Moreover, LAPTM4B promoted anchorage-dependent and -independent lung cancer cell growth and was crucial for cellular survival and the autophagy response under nutrient- and serum-deprived conditions. In addition, pathways analysis of a LAPTM4B-dependent gene expression profile revealed decreased activation of the canonical nuclear factor erythroid 2-like 2 (NRF2)-mediated pathway following LAPTM4B knockdown. Further, we found that LAPTM4B augmented the expression and nuclear translocation of the NRF2 transcription factor following serum deprivation pointing to the probable role of the novel LAPTM4B/NRF2 signaling axis in promoting lung cancer cell survival. All in all, our study points to molecular field of cancerization profiles in the normal-appearing airway that highly signify the nearby lung tumor and comprise early mechanisms (e.g. LAPTM4B) in lung carcinogenesis. Citation Format: Yuho Maki, Junya Fujimoto, Suk-Young Yoo, Melinda Garcia, Adam Gower, Li Shen, Chi-Wan Chow, Carmen Behrens, Neda Kalhor, Cesar Moran, Jing Wang, Avrum Spira, Kevin R. Coombes, Ignacio I. Wistuba, Humam Kadara. Transcriptomic architecture of the field of cancerization in the adjacent normal-appearing airway: Early mechanisms in lung carcinogenesis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1597. doi:10.1158/1538-7445.AM2014-1597