Superoxide Dismutase 3 Expression Research Articles

SOD3 regulates FLT1 to affect bone metabolism by promoting osteogenesis and inhibiting adipogenesis through PI3K/AKT and MAPK pathways

Osteoporosis is a chronic disease that seriously affects the quality of life and longevity of the elderly, so exploring the mechanism of osteoporosis is crucial for drug development and treatment. Bone marrow mesenchymal stem cells are stem cells with multiple differentiation potentials in bone marrow, and changing their differentiation direction can change bone mass. As an extracellular superoxide dismutase, Superoxide Dismutase 3 (SOD3) has been proved to play an important role in multiple organs, but the detailed mechanism of action in bone metabolism is still unclear.In this study, the results of clinical serum samples ELISA and single cell sequencing chip analysis proved that the expression of SOD3 was positively correlated with bone mass, and SOD3 was mainly expressed in osteoblasts and adipocytes and rarely expressed in osteoblasts in BMSCs. In vitro experiments showed that SOD3 can promote osteogenesis and inhibit adipogenesis. Compared with WT mice, the mice that were knocked out of SOD3 had a significant decrease in bone mineral density and significant changes in related parameters. The results of HE and IHC staining suggested that knocking out SOD3 would lead to fat accumulation in the bone marrow cavity and weakened osteogenesis. Both in vitro and in vivo experiments indicated that SOD3 affects bone metabolism by promoting osteogenesis and inhibiting adipogenesis. The results of transcriptome sequencing and revalidation showed that SOD3 can affect the expression of FLT1. Through in vitro experiments, we proved that FLT1 can also promote osteogenesis and inhibit adipogenesis. In addition, through the repeated experiments, the interaction between the two molecules (SOD3 and FLT1) was verified again. Finally, it was verified by WB that SOD3 regulates FLT1 to affect bone metabolism through PI3K/AKT and MAPK pathways.

Changes in superoxide dismutase 3 (SOD3) expression in periodontal tissue during orthodontic tooth movement of rat molars and the effect of SOD3 on in vitro hypoxia-exposed rat periodontal ligament cells.

Hypoxia during orthodontic tooth movement (OTM) induces reactive oxygen species (ROS) production in periodontal tissues. Superoxide dismutase 3 (SOD3) is an anti-inflammatory enzyme that protects cells from ROS. This study investigated the expression and function of SOD3 during rat OTM and in hypoxia-exposed rat periodontal ligament (PDL) cells. OTM of right maxillary first molars were performed in 8-week-old male Sprague-Dawley rats using closed-coil spring for 1 and 14 days (n = 6 per group). SOD3 and hypoxia-inducible factor 1-alpha (HIF-1α) protein expression was evaluated by immunohistochemistry. The effects of SOD3 on cell viability and proliferation, ROS production, and mRNA expression of Hif1-α, receptor activator of nuclear factor kappa-Β ligand (Rankl), and osteoprotegerin (Opg) in PDL cells and osteoclast differentiation were investigated under normal and hypoxic conditions. SOD3 expression in PDL tissues significantly decreased on the compression side on day 1 and on both sides on day 14 of OTM. HIF-1α levels significantly increased on the compression side on day 14. Cell viability, cell proliferation, and Opg mRNA expression decreased, whereas ROS production and Hif1-α and Rankl mRNA expression increased in the PDL cells upon SOD3 silencing. Hypoxia reduced Sod3 and Opg mRNA expression and increased ROS, Rankl mRNA expression, and osteoclast formation; SOD3 treatment attenuated these effects. SOD3 plays a role in periodontal tissue remodelling during OTM and in hypoxia-exposed PDL cells through ROS, HIF-1α, and RANKL/OPG pathways. Moreover, SOD3 treatment could attenuate the negative effects of hypoxia on the PDL cells.

The Effect of Extracellular Superoxide Dismutase (SOD3) Gene in Lung Cancer.

BackgroundThe recognition of new diagnostic and prognostic biological markers for lung cancer, the most severe malignant tumor, is an essential and eager study. In a microenvironment, superoxide dismutase 3 (SOD3) can adjust active oxygen, and it refers to a secreted antioxidant enzyme. It was also found to be cancer-related, and in lung cancer, it was remarkably down-regulated. More and more new cancer research focuses on the function of SOD3. Despite this, there is no good description of SOD3 function in the LC progression.MethodsThrough bioinformatics analysis, we found that SOD3 was a possible novel lung cancer gene in this study. We analyzed data sets from Gene Expression Comprehensive Database (GEO) and the Cancer Genome Atlas (TCGA), and SOD3 expression was studied in lung cancer. This study estimated the SOD3 diagnosis and prognosis through gene expression differential display, gene set enrichment analysis (GSEA), enrichment and genomes (KEGG) analysis, and gene ontology (GO). Then in order to investigate the SOD3 presentation in lung cancer cells, we used Western Blot and also applied Flow cytometry to detect the impact of anti-tumor medicine on tumor cell apoptosis.ResultsWe found that the expression level of SOD3 in lung cancer was low (P = 4.218E-29), while the survival of lung cancer patients with high SOD3 expression was shorter (LUSC p =0.00086, LUAD p=0.00038). According to the result of western blot, the expression of SOD3 in tumor cells was higher than that in normal cells. The ratio of early apoptosis induced by anti-cancer drugs was 10.5% in normal cells, 35.1% in squamous cell carcinoma and 36.9% in adenocarcinoma.The SOD3 high expression was associated with poor survival probability by multivariate analysis (HR: 1.006, 95% CI 1.002–1.011, p=0.006). Moreover, SOD3 high expression group had higher ESTIMATE scores, and larger amount of immune infiltrating cells. SOD3 expression is correlated with PDCD1 and CTLA4 expression.ConclusionsSOD3 gene can be used as a prognostic gene in lung cancer patients, and lung cancer patients with high expression of this gene can reap worse prognostic outcome. It can be used as a new clinical method and prognosticator for lung cancer patients.

Combined action of FOXO1 and superoxide dismutase 3 promotes MDA-MB-231 cell migration

Superoxide dismutase 3 (SOD3), one of SOD isozymes, maintains extracellular redox homeostasis through the dismutation reaction of superoxide. Loss of SOD3 in tumor cells induces oxidative stress and exacerbates tumor progression; however, interestingly, overexpression of SOD3 also promotes cell proliferation through the production of hydrogen peroxide. In this study, we investigated the functional role of SOD3 in human breast cancer MDA-MB-231 cell migration and the molecular mechanisms involved in high expression of SOD3 in MDA-MB-231 cells and human monocytic THP-1 cells. The level of histone H3 trimethylation at lysine 27 (H3K27me3), a marker of gene silencing, was decreased in 12-O-tetra-decanoylphorbol-13-acetate (TPA)-treated THP-1 cells. Also, that reduction was observed within the SOD3 promoter region. We then investigated the involvement of H3K27 demethylase JMJD3 in SOD3 induction. The induction of SOD3 and the reduction of H3K27me3 were inhibited in the presence of JMJD3 inhibitor, GSK-J4. Additionally, it was first determined that the knockdown of the transcription factor forkhead box O1 (FOXO1) significantly suppressed TPA-elicited SOD3 induction. FOXO1-mediated SOD3 downregulation was also observed in MDA-MB-231 cells, and knockdown of FOXO1 and SOD3 suppressed cell migration. Our results provide a novel insight into epigenetic regulation of SOD3 expression in tumor-associated cells, and high expression of FOXO1 and SOD3 would participate in the migration of MDA-MB-231 cells.

SOD3 deficiency induces liver fibrosis by promoting hepatic stellate cell activation and epithelial-mesenchymal transition.

Hepatic stellate cell (HSC) activation plays an important role in the pathogenesis of liver fibrosis, and epithelial-mesenchymal transition (EMT) is suggested to potentially promote HSC activation. Superoxide dismutase 3 (SOD3) is an extracellular antioxidant defense against oxidative damage. Here, we found downregulation of SOD3 in a mouse model of liver fibrosis induced by carbon tetrachloride (CCl4 ). SOD3 deficiency induced spontaneous liver injury and fibrosis with increased collagen deposition, and further aggravated CCl4 -induced liver injury in mice. Depletion of SOD3 enhanced HSC activation marked by increased α-smooth muscle actin and subsequent collagen synthesis primarily collagen type I in vivo, and promoted transforming growth factor-β1 (TGF-β1)-induced HSC activation in vitro. SOD3 deficiency accelerated EMT process in the liver and TGF-β1-induced EMT of AML12 hepatocytes, as evidenced by loss of E-cadherin and gain of N-cadherin and vimentin. Notably, SOD3 expression and its pro-fibrogenic effect were positively associated with sirtuin 1 (SIRT1) expression. SOD3 deficiency inhibited adenosine monophosphate-activated protein kinase (AMPK) signaling to downregulate SIRT1 expression and thus involving in liver fibrosis. Enforced expression of SIRT1 inhibited SOD3 deficiency-induced HSC activation and EMT, whereas depletion of SIRT1 counteracted the inhibitory effect of SOD3 in vitro. These findings demonstrate that SOD3 deficiency contributes to liver fibrogenesis by promoting HSC activation and EMT process, and suggest a possibility that SOD3 may function through modulating SIRT1 via the AMPK pathway in liver fibrosis.

Fructose Increases the Expression of Uric Acid-Induced Oxidative Stress Genes, NOX4 and FOXO3, in Cultured HepG2 Cells

Abstract Objectives Uric acid is the final product of purine metabolism. The role of uric acid in oxidative stress is not clear. Studies have shown uric acid as antioxidant as well as pro-oxidant. High fructose sugar consumption increases uric acid levels by ATP depletion and the subsequent formation AMP which is a uric acid precursor. In our study, we investigated the effect of dose dependent treatments of fructose, uric acid, or a combination of both uric acid and fructose on expression of oxidative stress-related genes, mainly NADPH oxidase 4 (NOX4), superoxide dismutase 3 (SOD3), Forkhead Box O3 (FOXO3) and xanthine dehydrogenase (XDH) in cultured Hep G2 cells. Methods Human hepatocellular carcinoma [HEPG2] (ATCC HB8065) cells were treated with serum-free medium containing either 10 mM fructose, soluble uric acid (0.25 mM, 0.5 mM, or 0.75 mM), or a combination of fructose and uric acid. The cells were collected at the end of each incubation period (30 min, 2 and 24 hours) to extract total RNA. cDNA was synthesized from the extracted RNA. TaqMan assays were designed for use on real-rime PCR platform (QuantStudio 12 K Flex). TaqMan open array primers were custom-made by Thermo Fisher Scientific. Target quantification values were normalized against GAPDH levels and a combination of students’ t-test and ANOVA were applied. Results Soluble uric acid, either by itself or in conjunction with fructose, did not change the expression of the tested genes at 30 minutes or 2 hours. However, after 24 hours of incubation, uric acid increased the expression of NOX4 by 2 and FOXO3 by 1.5-fold (p < 0.05) whereas uric acid plus fructose-containing media increased the expression of NOX4 by 3.5 and FOXO3 by 2-fold (p < 0.05) after 24 hours of incubation as compared to control. No treatment differences were observed in the expression of SOD3. Conclusions These findings demonstrate that fructose increases the expression of uric acid-induced oxidative stress related genes. Funding Sources None.

Regulation of Extracellular Redox Homeostasis in Tumor Microenvironment

Excessive generation of reactive oxygen species (ROS) has been implicated in the progression of tumors. Superoxide dismutase 3 (SOD3) is a copper-containing secretory antioxidative enzyme that plays a critical role in redox homeostasis, particularly in extracellular spaces. Considerable evidence suggests that SOD3 protein expression is significantly decreased or lost in several tumor tissues, and this loss results in tumor metastasis. On the other hand, epigenetic disturbances, including DNA hyper-/hypomethylation, histone de/acetylation, and histone de/methylation, may be involved in tumorigenesis and the progression of metastasis. However, regulation of SOD3 in the tumor microenvironment and the involvement of epigenetics in its expression remain unclear. To elucidate the molecular mechanisms underlying SOD3 expression, we investigated the involvement of epigenetics, including DNA methylation and histone modifications, in its regulation in tumor cells and macrophages. SOD3 expression in human monocytic THP-1 cells and human lung cancer A549 cells was silenced by DNA hypermethylation within the SOD3 promoter region. Furthermore, the DNA demethylase, ten-eleven translocation 1, was shown for the first time to play a key role in regulation of DNA methylation within that region. We also demonstrated that myocyte enhancer factor 2 functioned as one of the transcription factors of SOD3 expression in THP-1 cells. Collectively, these novel results will contribute to the elucidation of epigenetic redox regulation, and may provide important insights into tumorigenesis and tumor metastasis.

A small molecule promotes cartilage extracellular matrix generation and inhibits osteoarthritis development

Degradation of extracellular matrix (ECM) underlies loss of cartilage tissue in osteoarthritis, a common disease for which no effective disease-modifying therapy currently exists. Here we describe BNTA, a small molecule with ECM modulatory properties. BNTA promotes generation of ECM components in cultured chondrocytes isolated from individuals with osteoarthritis. In human osteoarthritic cartilage explants, BNTA treatment stimulates expression of ECM components while suppressing inflammatory mediators. Intra-articular injection of BNTA delays the disease progression in a trauma-induced rat model of osteoarthritis. Furthermore, we identify superoxide dismutase 3 (SOD3) as a mediator of BNTA activity. BNTA induces SOD3 expression and superoxide anion elimination in osteoarthritic chondrocyte culture, and ectopic SOD3 expression recapitulates the effect of BNTA on ECM biosynthesis. These observations identify SOD3 as a relevant drug target, and BNTA as a potential therapeutic agent in osteoarthritis.

Antioxidant peptides derived from the hydrolyzate of purple sea urchin (Strongylocentrotus nudus) gonad alleviate oxidative stress in Caenorhabditis elegans

The papain hydrolyzate prepared from purple sea urchin (Strongylocentrotus nudus) gonad exerts significant antioxidant activity. Through ultrafiltration, gel filtration and high performance liquid chromatography, the active fractions from the hydrolyzate were screened by alleviating paraquat-induced oxidative stress in Caenorhabditis elegans, and the peptide components were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Two antioxidant peptides SnP7 (AAVPSGASTGIYEALELR, 1805.03 Da) and SnP10 (NPLLEAFGNAK, 1173.34 Da) exhibit significant antioxidant capacity, which reduce reactive oxygen species (ROS) level and the expression of superoxide dismutase-3 (SOD-3) and heat shock protein-16.2 (HSP-16.2) in oxidation-damaged nematodes. Further studies indicated that SnP7 and SnP10 induce DAF-16 nuclear translocation and the expression of stress-related genes such as sod-3. RNA interference (RNAi) suggested that peptide-induced enhancement of resistance is dependent on DAF-16. Taken together, S. nudus antioxidant peptides might act through activate DAF-16 signaling pathway, and induce the expression of DAF-16 target genes that enhance antioxidant potential of organisms.

The MEF2A and MEF2D function as scaffold proteins that interact with HDAC1 or p300 in SOD3 expression in THP-1 cells

Superoxide dismutase 3 (SOD3) is a SOD isozyme and plays a key role in extracellular redox homeostasis. We previously demonstrated that histone acetylation is involved in 12-O-tetra-decanoylphorbol-13-acetate (TPA)-elicited SOD3 expression in human monocytic THP-1 cells; however, the molecular mechanisms responsible for its expression have not yet been elucidated in detail. The results of the present study demonstrated that the binding of histone deacetylase 1 (HDAC1) to the SOD3 promoter region contributed to SOD3 silencing in basal THP-1 cells. On the other hand, the dissociation of HDAC1 from the SOD3 promoter region and the enrichment of p300, a histone acetyltransferase (HAT), within that region were observed in TPA-induced THP-1 cells. Myocyte enhancer factor 2 (MEF2) functions as a scaffold protein that interacts with histone deacetylases (HDAC) or HAT and regulates gene expression. The present results showed that the MEF2A and MEF2D function as mediators for TPA-elicited SOD3 expression by interacting with HDAC or p300. Additionally, the knockdown of MEF2A or MEF2D in human skin fibroblasts suppressed SOD3 expression at the mRNA and protein levels. Our results provide an insight into epigenetic regulation of redox gene expression, and may ultimately contribute to suppressing the progression of tumours and vascular diseases.

P-88 - Involvement of histone acetylation and methylation in SOD3 regulation in human monocytic THP-1 cells

Superoxide dismutase 3 (SOD3), a secretory SOD isozyme, displays a unique and cell-specific expression pattern, and epigenetics plays a critical role in its expression. To date, we have determined that histone acetylation governs phorbol ester (TPA)-elicited SOD3 expression in human monocytic THP-1 cells; however, the molecular mechanisms involving its induction remains unclear. Present data demonstrated that histone deacetylase 1 (HDAC1) and histone acetyltransferase (p300) coordinated SOD3 induction. Moreover, it was determined that myocyte enhancer factor 2 A (MEF2A) and MEF2D function as scaffold proteins, indicating that MEF2/HDAC1 or MEF2/p300 complex regulates SOD3 expression. On the other hand, asymmetric H4R3me2 (H4R3me2a), an epigenetic marker for transcription activation, was also induced in TPA-treated THP-1 cells, suggesting that histone methylation regulates SOD3 expression as well. As expected, our ChIP data clearly showed that the level of H4R3me2a within the proximal SOD3 promoter region was significantly enhanced. Overall, we have found that histone modifications including acetylation and methylation govern SOD3 expression in THP-1 cells.

66 - Copper Transporter, Antioxidant-1 (Atox-1), Modulates Redox Homeostasis during Phorbol-Ester-Induced THP-1 Cell Differentiation

Copper (Cu), an essential micronutrient, is involved in vascular remodeling, and its bioavailability regulated by Cu transporter proteins, such as ATP7A and antioxidant-1 (Atox-1). Superoxide dismutase 3 (SOD3), which has a Cu ion in the active site, plays a pivotal role in the redox homeostasis, and its loss exacerbates vascular diseases. We have reported that SOD3 expression induces in phorbol ester (TPA)-treated human monocytic THP-1 cells; however, the involvement of Cu ion in its induction is entirely unknown. TPA stimulation in THP-1 cells induced ATP7 expression and Atox-1 nuclear translocation through PKC and MEK/ERK signaling. According to the previous report, which shows that Atox-1 functions as a transcription factor for SOD3, we demonstrated the role of Atox-1 in TPA-elicited SOD3 induction. Overexpression of Atox-1 protein enhanced TPA-elicited SOD3 expression, and knockdown of Atox-1 with siRNA suppressed its expression, suggesting that Atox-1 plays a pivotal role in SOD3 regulation in THP-1 cells. Additionally, knockdown of Atox-1 suppressed mRNA expression of gp91phox, an essential component of NOX2. Overall, we have determined that intracellular Cu modulation via its transporter might regulate redox homeostasis in THP-1 cells by the alteration in expression of SOD3 and gp91phox.

Abstract WP268: Leukemia Inhibitory Factor Upregulates Superoxide Dismutase 3 in Neurons via Activation of Myeloid Zinc Finger-1

Objective: To determine whether leukemia inhibitory factor (LIF) upregulates superoxide dismutase 3 (SOD3), a neuroprotective antioxidant enzyme, through the transcription factor myeloid zinc finger-1 (MZF-1). Hypothesis: MZF-1 facilitates LIF-mediated neuroprotection by increasing transcription of the SOD3 gene in neurons. Methods: After middle cerebral artery occlusion or sham surgery, male Sprague-Dawley rats were injected with PBS or LIF (125 μg/kg) (n=4 per group). Rats were euthanized 72 h after injury and western blotting was used to measure MZF-1 protein expression in brain tissue. For in vitro studies, rat neurons were transfected with scrambled or MZF-1 siRNA (n=3 per group). Neurons were treated with PBS or 200 ng/mL LIF prior to 24 h in vitro ischemia induced by oxygen glucose deprivation. Lactate dehydrogenase (LDH) release was measured to assess neuronal death. MZF-1 levels were quantified in cultured neurons with immunocytochemistry. SOD3 and MZF-1 mRNA levels were measured with real-time PCR. Results: LIF (0.938 OD units ± 0.170), but not PBS (0.562 OD units ± 0.223), significantly increased MZF-1 protein expression in ipsilateral tissue 72 h after stroke compared to sham surgery (0.411 OD units ± 0.039, p<0.05). LIF treatment prior to 24 h in vitro ischemia significantly increased the percentage of MZF-1-positive neurons (52.17 % ± 0.93) compared to PBS 44.84 % ± 1.11, p<0.01). PCR results confirmed the increase in MZF-1 mRNA (1.89 fold change ± 0.33) in LIF-treated neurons compared to PBS-treated neurons (1.00 fold change ± 0.23, p<0.05). Moreover, LIF increased SOD3 mRNA after 24 h ischemia (1.35 fold change ± 0.03) compared to PBS (1.00 fold change ± 0.13, p<0.05). LIF decreased LDH release (363,967 ± 68,557 neuronal units) compared to PBS (559,856 ± 60,555 neuronal units, p<0.05) among neurons transfected with scrambled siRNA. However, MZF-1 siRNA attenuated the neuroprotective effect of LIF (690,633 neuronal units ± 19,167; p<0.05). Conclusions: MZF-1 plays a fundamental role in a novel neuroprotective pathway by enhancing SOD3 expression and provides insight regarding protection by antioxidant enzymes during stroke.

Leukemia Inhibitory Factor Protects Neurons from Ischemic Damage via Upregulation of Superoxide Dismutase 3.

Leukemia inhibitory factor (LIF) has been shown to protect oligodendrocytes from ischemia by upregulating endogenous antioxidants. The goal of this study was to determine whether LIF protects neurons during stroke by upregulating superoxide dismutase 3 (SOD3). Animals were administered phosphate-buffered saline (PBS) or 125 μg/kg LIF at 6, 24, and 48 h after middle cerebral artery occlusion or sham surgery. Neurons were isolated from rat pups on embryonic day 18 and used between 7 and 15 days in culture. Cells were treated with LIF and/or 10 μM Akt inhibitor IV with PBS and 0.1 % DMSO acting as vehicle controls. Neurons transfected with scrambled or SOD3 small interfering RNA (siRNA) were subjected to 24-h ischemia after PBS or LIF treatment. LIF significantly increased superoxide dismutase activity and SOD3 expression in ipsilateral brain tissue compared to PBS. Following 24-h ischemia, LIF reduced cell death and increased SOD3 messenger RNA (mRNA) in vitro compared to PBS. Adding Akt inhibitor IV with LIF counteracted the decrease in cell death. Partially silencing the expression of SOD3 using siRNA prior to LIF treatment counteracted the protective effect of LIF-alone PBS treatment. These results indicate that LIF protects neurons in vivo and in vitro via upregulation of SOD3.

Abstract T P248: Leukemia Inhibitory Factor Induced-Akt Activation Protects Neurons from Ischemic Damage by Increasing Superoxide Dismutase Activity and Expression

Objective: To determine the molecular mechanisms by which leukemia inhibitory factor (LIF) protects neurons during permanent middle cerebral artery occlusion (MCAO). Hypothesis: LIF protects neurons from ischemic oxidative injury through Akt-mediated increases in superoxide dismutase 3 (SOD3) expression and total SOD activity. Methods: Male Sprague-Dawley rats injected with vehicle (PBS) or LIF (125 μg/kg) were euthanized 24, 48, and 72 h post-MCAO or sham surgery for assessment of SOD activity and SOD3 expression. Rat cortical neurons were subjected to 24 h oxygen glucose deprivation or normoxia following treatment with vehicle , 50, 200, or 1000 ng/mL LIF (n=3 per group). In a third experiment, neurons were treated with vehicle, 50 ng/mL LIF,10 μM Akt inhibitor, or 50 ng/mL LIF+10 μM Akt inhibitor (n=3 per group) prior to oxygen glucose deprivation. Lactate dehydrogenase levels in media were measured to assess neuronal death. We used immunocytochemistry to assess expression of SOD3, phospho-Akt (Ser473), and myeloid zinc finger-1 in neurons. Results: LIF significantly increased brain SOD activity (2.085 ± 0.476 U/mg lysate; n=5) compared to vehicle (0.919 ± 0.285 U/mg lysate; n=7) 72 h post-MCAO (p<0.05). LIF significantly increased SOD3 protein expression in the brain (3.707 ± 0.541 units; n=3) compared to vehicle (1.401 ± 0.825 units; n=3) at 72 h post-MCAO (p<0.05). Co-localization of phospho-Akt and SOD3 occurred 24 h post-MCAO. Additionally, 50 ng/mL LIF (0.789 ± 0.018 U/mL media; n=3) significantly decreased lactate dehydrogenase levels in vitro compared to vehicle (1.000 ± 0.023 U/mL media; n=3) (p<0.0001). Co-incubation of 50/mL ng LIF with 10 μM Akt inhibitor (1.070 ±0.106 U/mL media; n=3) reversed the protective effect of LIF (0.705 ± 0.050 U/mL media; n=3) (p<0.01). Increases in SOD3, phospho-Akt, and myeloid zinc finger-1 staining after oxygen glucose deprivation and LIF were abolished upon Akt inhibition. Conclusion: Our data demonstrates that LIF-mediated protection against ischemia in vivo and in vitro results from Akt-dependent increases in SOD3 expression and SOD activity.

Farnesoid X receptor antagonizes JNK signaling pathway in liver carcinogenesis by activating SOD3.

The farnesoid X receptor (FXR) is a key metabolic and homeostatic regulator in the liver. In the present work, we identify a novel role of FXR in antagonizing c-Jun N-terminal kinase (JNK) signaling pathway in liver carcinogenesis by activating superoxide dismutase 3 (SOD3) transcription. Compared with wild-type mouse liver, FXR(-/-) mouse liver showed elevated JNK phosphorylation. JNK1 deletion suppressed the increase of diethylnitrosamine-induced tumor number in FXR(-/-) mice. These results suggest that JNK1 plays a key role in chemical-induced liver carcinogenesis in FXR(-/-) mice. We found that ligand-activated FXR was able to alleviate H₂O₂or tetradecanoylphorbol acetate-induced JNK phosphorylation in human hepatoblastoma (HepG2) cells or mouse primary hepatocytes. FXR ligand decreased H₂O₂-induced reactive oxygen species (ROS) levels in wild-type but not FXR(-/-) mouse hepatocytes. FXR knockdown abolished the inhibition of 3-[2-[2-chloro-4-[[3-(2,6-dichlorophenyl)-5-(1-methylethyl)-4-isoxazolyl]methoxy]phenyl]ethenyl]-Benzoic acid (GW4064) on JNK phosphorylation and ROS production induced by H₂O₂in HepG2 cells. The gene expression of SOD3, an antioxidant defense enzyme, was increased by FXR activation in vitro and in vivo. An FXR-responsive element, inverted repeat separated by 1 nucleotide in SOD3 promoter, was identified by a combination of transcriptional reporter assays, EMSAs, and chromatin immunoprecipitation assays, which indicated that SOD3 could be a direct FXR target gene. SOD3 knockdown abolished the inhibition of GW4064 on JNK phosphorylation induced by H₂O₂in HepG2 cells. In summary, FXR may regulate SOD3 expression to suppress ROS production, resulting in decreasing JNK activity. These results suggest that FXR, as a novel JNK suppressor, may be an attractive therapeutic target for liver cancer treatment.

Superoxide Dismutase 3 Controls Adaptive Immune Responses and Contributes to the Inhibition of Ovalbumin-Induced Allergic Airway Inflammation in Mice

The extracellular superoxide dismutase 3 (SOD3) is an isoform of SOD. Extensive studies have been focused on role of SOD3 as an antioxidant. However, the role of SOD3 in the immune responses that contribute to the inhibition of allergic lung inflammation has not been investigated. Here, we report for the first time that SOD3 specifically inhibits dendritic cell maturation. Subsequently, SOD3 controls T cell activation and proliferation, and T helper 2 (Th2) and Th17 cell differentiation. As a consequence, the administration of SOD3 into mice alleviated Th2-cell-mediated ovalbumin (OVA)-induced allergic asthma. In addition, we demonstrated that SOD3 inhibits OVA-induced airway extracellular remodeling and Th2 cell trafficking. Through mass spectrometry analysis, the proteins interacting with SOD3 in the lung of asthma were identified. And it was revealed that signaling molecules, such as transforming growth factor (TGF) and epidermal growth factor (EGF) receptor, adhesion and adaptor molecules, kinases, phosphatases, NADPH oxidase, and apoptosis-related factor, were involved, which were altered by administration of SOD3. Relatively severe asthma was observed in SOD3 KO mice and was ameliorated by both the administration of SOD3 and adoptive transfer of SOD3-sufficient CD4 T cells. Moreover, the expression of endogenous SOD3 in the lung peaked early in OVA challenge and gradually decreased upon disease progression, while both SOD1 and SOD2 expression changed relatively little. Thus, our data suggest that SOD3 is required to maintain lung homeostasis and acts, at least in part, as a controller of signaling and a decision maker to determine the progression of allergic lung disease.