Modulation of Nrf2/HO-1 by Natural Compounds in Lung Cancer.

Oxidative stresses (OSs) are considered a pivotal factor in creating various pathophysiological conditions. Cells have been able to move forward by modulating numerous signaling pathways to moderate the defects of these stresses during their evolution. The company of Kelch-like ECH-associated protein 1 (Keap1) as a molecular sensing element of the oxidative and electrophilic stress and nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) as a master transcriptional regulator of the antioxidant response makes a master cytoprotective antioxidant pathway known as the Keap1/Nrf2 pathway. This pathway is considered a dual-edged sword with beneficial features for both normal and cancer cells by regulating the gene expression of the array of endogenous antioxidant enzymes. Heme oxygenase-1 (HO-1), a critical enzyme in toxic heme removal, is one of the clear state indicators for the duality of this pathway. Therefore, Nrf2/HO-1 axis targeting is known as a novel strategy for cancer treatment. In this review, the molecular mechanism of action of natural antioxidants on lung cancer cells has been investigated by relying on the Nrf2/HO-1 axis.

Hypouricemic and nephroprotective effects of palmatine from Cortex Phellodendri Amurensis: A uric acid modulator targeting Keap1-Nrf2/NLRP3 axis.

ETHNOPHARMACOLOGICAL RELEVANCE: Palmatine (Pal) is a major bioactive alkaloid originated from ancient Chinese herbal medicine Cortex Phellodendri Amurensis (CPA), which has long been applied to treat hyperuricemia (HUA)-related diseases. Pal possesses potent anti-inflammatory and anti-oxidant effects against metabolic diseases. However, its potential beneficial effect against PO (potassium oxonate)/HX (hypoxanthine)-induced HUA remains elusive. AIM OF THE STUDY: This study aimed to investigate the potential pharmacological effect and mechanism of Pal on PO/HX-induced HUA in mice. MATERIAL AND METHODS: A mouse model of HUA was established by co-administration of PO/HX once daily for 7 consecutive days. The HUA mice were orally given three doses (25, 50 and 100 mg/kg) of Pal daily for a week. Febuxostat (Feb, 5 mg/kg) was given as a positive control. At the scheduled termination of the experiment, the whole blood, liver and kidney were collected for subsequent analyses. The concentrations of uric acid (UA), creatinine (CRE) and blood urea nitrogen (BUN), and activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) were evaluated. Histopathological alterations of the kidney were detected by H&E staining. The inflammatory and oxidative stress status was detected by assay kits. Additionally, key proteins involved in the urate transporter, Keap1-Nrf2 and TXNIP/NLRP3 signaling pathways were evaluated by immunohistochemistry and Western blotting. Finally, molecular docking was employed to probe the binding characteristics of Pal and target proteins Keap1, NLRP3, URAT1 and HO-1. RESULTS: Administration of Pal substantially decreased the elevated kidney weight, lowered UA, CRE and BUN levels, and attenuated abnormal histopathological alterations. Meanwhile, treatment with Pal also dramatically lowered hepatic XOD and ADA activities. Besides, Pal treatment effectively mitigated the renal inflammatory and oxidative stress markers. Further mechanistic investigation indicated Pal distinctly downregulated the protein levels of GLUT9 and URAT1, while up-regulated the expression levels of OAT1 and ABCG2. Pal also restored Nrf2 activation, promoted subsequent expression of anti-oxidative enzymes, and downregulated the expressions of TXNIP, NLRP3, apoptosis-associated speck-like (ASC), caspase-1, IL-1ß and IL-18. Molecular docking analysis also indicated Pal firmly bound with Keap1, NLRP3, URAT1 and HO-1. CONCLUSIONS: These findings indicated that Pal exhibited favorable anti-HUA effect via modulating the expressions of transporter-related proteins and suppressing XOD activity. Furthermore, Pal also alleviated HUA-induced kidney injury, which was at least partially related to restoring Keap1-Nrf2 pathway and inhibiting TXNIP/NLRP3 inflammasome. Our investigation was envisaged to provide experimental support for the traditional application of CPA and CPA-containing classical herbal formulas in the management of HUA-related diseases and might provide novel dimension to the clinical application of Pal.

Calcitriol confers neuroprotective effects in traumatic brain injury by activating Nrf2 signaling through an autophagy-mediated mechanism.

BACKGROUND: The present study aimed to further explore the potential interaction between oxidative stress and autophagy in the progression of traumatic brain injury (TBI) and therapeutic mechanism of calcitriol, the active form of vitamin D (VitD). METHODS: Neuroprotective effects of calcitriol were examined following TBI. We further evaluated the impacts of TBI and calcitriol treatment on autophagic process and nuclear factor E2-related factor 2 (Nrf2) signaling. RESULTS: We found that treatment of calcitriol markedly ameliorated the neurological deficits and histopathological changes following TBI. The brain damage impaired autophagic flux and impeded Nrf2 signaling, the major regulator in antioxidant response, consequently leading to uncontrolled and excessive oxidative stress. Meanwhile, calcitriol promoted autophagic process and activated Nrf2 signaling as evidenced by the reduced Keap1 expression and enhanced Nrf2 translocation, thereby mitigating TBI-induced oxidative damage. In support, we further found that chloroquine (CQ) treatment abrogated calcitriol-induced autophagy and compromised Nrf2 activation with increased Keap1 accumulation and reduced expression of Nrf2-targeted genes. Additionally, both CQ treatment and Nrf2 genetic knockout abolished the protective effects of calcitriol against both TBI-induced neurological deficits and neuronal apoptosis. CONCLUSIONS: Therefore, our work demonstrated a neuroprotective role of calcitriol in TBI by triggering Nrf2 activation, which might be mediated by autophagy.

Qiangjing Tablets Regulate Apoptosis and Oxidative Stress via Keap/Nrf2 Pathway to Improve the Reproductive Function in Asthenospermia Rats.

Asthenozoospermia (AZS), is a common cause of male infertility. Currently, most drugs for azoospermia lack desirable therapeutic efficiency, therefore developing new drug therapy is important. Qiangjing tablets could enhance renal function and improve sperm quality. The purpose of this study was to examine whether Qiangjing tablets could improve the reproductive function in azoospermia rats through activating the Nrf2/ARE pathway, and how to regulate energy metabolism and oxidative stress in this process. Sperm motility, sperm concentration and sperm viability were detected by WLJY-9000 Weili Digital Color Sperm Quality Detection System. HE staining was used to observe the pathological condition of testis in AZS rats. Cell apoptosis was analyzed by Tunnel staining and flow cytometry. The changes of mitochondrial membrane potential were detected by JC-1. The levels of Estradiol, testosterone and luteinizing hormone, activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and content of malondialdehyde (MDA) and glutathione (GSH) were detected by ELISA. The effects of Qiangjing Tablets on GC-1 spgs and Nrf2 protein were investigated through CCK-8 assay and western blot. The expression levels of HO-1, Keap1, and P-Nrf2 were detected by western blot. The results demonstrated that Qiangjing tablets upregulated levels of sperm motility, sperm concentration and sperm viability, which was shown to significantly increase levels of HO-1, Keap1, P-Nrf2, Estradiol and testosterone, along with increasing the activity of SOD, GSH-Px and GSH and suppressing the MDA content, luteinizing hormone and Vimentin level. Qiangjing tablets could significantly inhibit spermatogenic cells apoptosis and promote GC-1 spgs viability, increase PE/FITC ratio, mitochondrial membrane potential and reduc oxidative stress. Qiangjing tablets protected spermatogenic cell to upregulate male sex hormoneto, improved the sperm quality and reproductive function in AZS rats via activating the Keap/Nrf2 signaling pathway.

[Combined cytotoxicity mechanism of chlorpyrifos and carbofuran pesticides in vitro].

OBJECTIVE: To evaluate the single and combined effects of chlorpyrifos( CPF) and carbofuran( CF) pesticides on cell lines cultured in vitro, and clarify the pattern of joint action. METHODS: Rat pheochromocytoma( PC12 cells) were treated with different concentrations of CPF( 0, 50, 100, 200 and 400 µmol/L) and CF( 0, 25, 50, 100 and 200 µmol/L) for 12 h separately, the combined effects of two kinds of pesticides should be studied respectively in the low dose( CPF 50 µmol/L, CF 25 µmol/L) and high dose( CPF 200 µmol/L, CF 100 µmol/L) levels. After exposure, detectingacetylcholinesterase( ACh E) activity and using fluorescent probe 2', 7'-dichlorfluorescin diacetate( DCFH-DA), thiobarbituric acid( TBA) method, xanthine oxidation, 5, 5 '-dithio-bis-2-nitrobenzoic acid( DTNB) coloration to detect the intracellular reactive oxygen species( ROS) production, lipid peroxidation production malondialdehyde( MDA), activity of antioxidant enzymes superoxide dismutase( SOD) and glutathione peroxidase( GPx), respectively. RESULTS: Compared with the control group, CPF and CF could decrease the ACh E activity, induce ROS overproduction in a dose-effect way and increase the activity of SOD, GPx( P < 0. 01), but MDA content showed no significant change. Factorial ANOVA revealed that the combined effect of CPF and CF, there was no interaction at lower dose level, but interaction existed at higher dose level( P < 0. 01). The main mode of action was synergistic effect. CONCLUSION: Chlorpyrifos, carbofuran single or combined, has cytotoxicity effect. The main combined effect between chlorpyrifos and carbofuran is synergistic effect, oxidative stress damage may be one of the mechanisms.