Sulforaphane is often considered a ‘‘gold standard’’ among naturally-occurring Nrf2 activators (Agyeman et al., 2011).
The greatest FImax was observed with Protandim at 135-fold, followed by bardoxolone methyl at 67-fold, dimethyl fumarate at 55-fold, and sulforaphane at 21-fold
When compared contemporaneously in the AREc32-based assay, FImax observed was in the order Protandim > bardoxolone methyl > dimethyl fumarate > sulforaphane.
A recent laboratory study of dimethyl fumarate found that the compound activates Nrf2 in primary astrocytes, but not in the C6 glioma-derived cell line (Wilms et al., 2010), demonstrating that different cells may respond quite differently to Nrf2 activators
While Protandim, bardoxolone methyl, BG-12, and sulforaphane all have been demonstrated to modify gene expression profiles by activation of Nrf2, they have not been compared side by side, in the same cell line, under identical conditions.
This antiporter was recently found to be decreased by repeated cocaine exposure, and restoration of the activity prevented cocaine-primed drug seeking behavior in rats (Baker et al., 2003).
SLC7A11, induced 76-fold, encodes a cystine/glutamate antiporter responsible for maintaining extracellular glutamate in the brain, and for importing cystine necessary for glutathione synthesis (Albrecht et al., 2010).
The study also found that resveratrol, a putative activator of SIRT1 (Howitz et al., 2003), inhibited Nrf2-dependent transcription, apparently contradicting earlier reports that resveratrol activates Nrf2 (Chen et al., 2005; Ungvari et al., 2010).
Overexpression of the HSPB8-BAG3 complex also stimulates autophagy and facilitates the clearance of mutated aggregation-prone proteins, the accumulation of which characterizes many neurodegenerative disorders such as Alzheimer disease, Parkinson disease, and amyotrophic lateral sclerosis (Seidel et al., 2011).
TNFSF9 (aka CD137L), induced 19-fold, can induce maturation of human immature monocyte-derived dendritic cells leading to an enhanced capacity of the dendritic cells to stimulate protective T cell responses, as compared to classical dendritic cells (Tang et al., 2011).
In Alzheimer disease, 66 genes were identified that are also modulated by Protandim at the gene expression level. Of these 66 genes, the first 43 of them (65%) were regulated by Protandim in the opposing direction to that taken by the Alzheimer disease process. The beneficial effect of Protandim is further supported by the fact that of the 10 gene products currently targeted by drug therapies, eight of them are modulated by Protandim in the same direction that is proposed to be beneficial and caused by the drug.
In our gene expression data, SIRT1 was induced 1.75-fold by Protandim (p = 0.015).
AKR1B10, induced 72-fold, encodes aldo–keto reductase family 1 member B10 which efficiently detoxifies mutagenic and carcinogenic alpha, beta-unsaturated carbonyls such as 4-hydroxynonenal (Zhong et al., 2009).
PTGR1 (aka LTB4DH), induced 68-fold, encodes leukotriene B4-12-hydroxydehydrogenase, which is considered to be a key enzyme responsible for biological inactivation of prostaglandins and related eicosanoids (Tai et al., 2002).
HMOX1, induced 56-fold, encodes heme oxygenase-1, an antioxidant enzyme considered a hallmark of Nrf2 activation.
A likely explanation for the increased expression of GLRX2 (glutaredoxin 2) and NQO1 (NAD(P)H dehydrogenase, quinone 1) in colon carcinoma and of GLRX (glutaredoxin), HMOX1 (heme oxygenase-1), NQO1, and SOD1 (superoxide dismutase 1) in Alzheimer is that it represents an adaptive attempt to partially compensate for the increased level of oxidative stress associated with these diseases. These antioxidant genes are also upregulated by Protandim, which would provide additional antioxidant protection beyond that achieved by the ROS-dependent induction of these enzymes in the diseased tissues.
AIFM2 (aka AMID), induced 29-fold, is implicated in caspase-independent apoptosis and was found to be downregulated in a majority of human tumors (Wu et al., 2004b).
OSGIN1 (aka OKL38), induced 29-fold, is an oxidative stress response gene and a tumor suppressor gene (Yao et al., 2008).
GPX3, induced 20-fold, encodes an important antioxidant enzyme, glutathione peroxidase-3, found normally in plasma and kidney but underexpressed in head and neck cancers (Chen et al., 2011).
SQSTM1, induced 20-fold, encodes sequestosome-1, a participant in the autophagy pathway recently shown to be necessary to avoid premature senescence in human fibroblasts (Kang et al., 2011).
HSPB8, induced 19-fold, is a heat shock protein that forms a complex with BAG3 (also induced 1.43-fold).
For example, 19 genes products have been associated with atherosclerosis and are up or down-regulated by Protandim. Of these 19 genes, the first 16 listed (84%) were regulated by Protandim in the opposing direction to that taken by the atherosclerosis disease process. The probable benefit of this effect of Protandim is further supported by the fact that of the 11 gene products currently being targeted by drug interventions (Table 1, in bold type), nine of them (Table 1, marked by asterisks) are modulated by Protandim in the same direction that is proposed to be beneficial and caused by the therapeutic intervention.
In colon carcinoma, IPA analysis revealed 28 genes associated with the disease that were also modulated by Protandim treatment. Of these, the first 25 listed (89%) were regulated by Protandim in the opposing direction to that taken by the colon carcinoma disease process.
In addition, Protandim downregulated the one gene targeted by a chemotherapeutic drug, an antimetabolite inhibitor for that gene’s product, thymidylate synthetase
Bardoxolone methyl appeared to produce a biphasic induction, producing near maximal FI over a range of concentrations from less than 40 nM to 0.4 lM
After 52 weeks, the estimated glomerular filtration rate in the 75 mg/day treatment group had increased by 10.5 ± 1.8 ml/min/1.73 m2 (p < 0.001), representing an increase of about 32% when compared to entry values.
Patients with relapsing-remitting multiple sclerosis treated with BG-12 for 24 weeks showed significantly fewer new gadolinium-enhancing lesions, with significantly reduced probability of their evolution to T1-hypointense lesions than patients treated with placebo (Macmanus et al., 2011)
The study suggests that Nrf2 activation represents a viable new therapeutic approach for renal disease, as similar results are not achievable with currently available therapies
These studies suggest that Nrf2 activation may represent a promising new therapeutic approach for multiple sclerosis.
Sirtuin 1 (SIRT1) was shown to decrease acetylation of Nrf2, as well as Nrf2-dependent transcription.
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If you find BEL Commons useful in your work, please consider citing: Hoyt, C. T., Domingo-Fernández, D., & Hofmann-Apitius, M. (2018). BEL Commons: an environment for exploration and analysis of networks encoded in Biological Expression Language. Database, 2018(3), 1–11.