Higher Levels of Plasma Fetuin-A, Nrf2, and Cytokeratin 18 in Patients with Hashimoto's Disease

Objectives

Fetuin-A is a protein that exhibits proatherogenic, pro-inflammatory, and anti-inflammatory effects with increased insulin resistance and adipocyte dysfunction. The nuclear factor erythroid 2-related factor (Nrf2) is a transcription factor that is crucial for protecting cells against oxidative damage. As a cell death product, cytokeratin 18 (CK18) levels increase during necrosis and apoptosis of both normal and tumor cells. We analyzed the plasma levels of three biomarkers based on the hypothesis that they might be related to some pathophysiological pathways in Hashimoto's disease.

Methods

We compared 34 female patients with overt hypothyroidism due to Hashimoto's disease (Group 1) with 34 age-matched healthy females (Group 2). For comparison, plasma levels of thyroid-stimulating hormone (TSH), fetuin-A, Nrf2, and CK18 were measured in all participants.

Results

In group 1, the mean TSH levels (31.4±15.3) were significantly higher than those in group 2 (2.6±1.0) (p<0.001). The levels of mean fetuin-A (606.7±34.2) and Nrf2 (1.3±0.6) were found to be significantly higher in group 1 than in group 2 (440.0±34.2 vs. 0.7±0.2) (p<0.001 for both). CK18 levels in group 1 (0.36±0.13) were also significantly higher than in group 2 (0.26±0.16) (p=0.020). A significant correlation was observed between TSH levels and fetuin-A (r=0.401, p=0.001).

Conclusion

Increased levels of fetuin-A, Nrf2, and CK18 may be a consequence or cause of the pathophysiological pathways of Hashimoto's disease. The clinical significance of increased levels of these biomarkers requires further investigation.

Sulforaphane inhibits angiotensin II-induced cardiomyocyte apoptosis by acetylation modification of Nrf2

Oxidative stress is the central cause of angiotensin II (Ang II)-induced myocardial injury, and nuclear factor erythroid 2-related factor (Nrf2) is the core molecule of the anti-oxidant defense system. We have previously demonstrated that sulforaphane (SFN) can prevent Ang II-induced myocardial injury by activating Nrf2; however, the underlying molecular mechanism is still unclear. This study aimed to evaluate whether SFN prevents Ang II-induced cardiomyocyte apoptosis through acetylation modification of <i>Nrf2</i>. Wild-type and <i>Nrf2</i> knockdown embryonic rat cardiomyocytes (H9C2) were exposed to Ang II to induce apoptosis, oxidative stress, and inflammatory responses. SFN treatment significantly reduced Ang II-induced cardiomyocyte apoptosis, inflammation and oxidative stress. Activation of Nrf2 played a critical role in preventing cardiomyocyte apoptosis. After Nrf2 was knockdown, the anti-inflammatory, antioxidant stress of SFN were eliminated. Furthermore, Nrf2 activation by SFN was closely related to the decreased activity of histone deacetylases (HDACs) and increased histone-3 (H3) acetylation levels in <i>Nrf2</i> promoter region. These findings confirm that Nrf2 plays a key role in SFN preventing Ang II-induced cardiomyocyte apoptosis. SFN activates Nrf2 by inhibiting HDACs expression and activation.

Carnosine Alleviates Knee Osteoarthritis and Promotes Synoviocyte Protection via Activating the Nrf2/HO-1 Signaling Pathway: An In-Vivo and In-Vitro Study

The most common joint disease in the elderly is knee osteoarthritis (OA). It is distinguished by cartilage degradation, subchondral bone loss, and a decrease in joint space. We studied the effects of carnosine (CA) on knee OA in male Wistar rats. OA is induced by anterior cruciate ligament transection combined with medial meniscectomy (ACLT+MMx) method and in vitro studies are conducted in fibroblast-like synoviocyte cells (FLS). The pain was assessed using weight-bearing and paw-withdrawal tests. CA supplementation significantly reduced pain. The enzyme-linked immunosorbent assay (ELISA) method was used to detect inflammatory proteins in the blood and intra-articular synovial fluid (IASF), and CA reduced the levels of inflammatory proteins. Histopathological studies were performed on knee-tissue samples using toluidine blue and hematoxylin and eosin (H and E) assays. CA treatment improved synovial protection and decreased cartilage degradation while decreasing zonal depth lesions. Furthermore, Western blotting studies revealed that the CA-treated group activated nuclear factor erythroid 2-related factor (Nrf2) and heme oxygenase (HO-1) and reduced the expression of cyclooxygenase-2 (COX-2). FLS cells were isolated from the knee joints and treated with IL-1β to stimulate the inflammatory response and increase reactive oxygen species (ROS). The matrix metalloproteinase protein (MMP's) levels (MMP-3, and MMP-13) were determined using the reverse transcription-polymerase chain reaction (RT-PCR), and CA treatment reduced the MMP's expression levels. When tested using the 2',7'-dicholorodihydrofluroscene diacetate (DCFDA) assay and the 5,5',6,6'-tetracholoro-1,1',3,3'-tertraethylbenzimidazolcarboc janine iodide (JC-1) assay in augmented ROS FLS cells, CA reduced the ROS levels and improved the mitochondrial membrane permeability. This study's investigation suggests that CA significantly alleviates knee OA both in vitro and in vivo.

Sevoflurane preconditioning protects experimental ischemic stroke by enhancing anti-inflammatory microglia/macrophages phenotype polarization through GSK-3β/Nrf2 pathway

Aims

Sevoflurane preconditioning (SPC) results in cerebral ischemic tolerance; however, the mechanism remains unclear. Promoting microglia/macrophages polarization from pro‐inflammatory state to anti‐inflammatory phenotype has been indicated as a potential treatment target against ischemic stroke. In this study, we aimed to assess the effect of SPC on microglia polarization after stroke and which signaling pathway was involved in this transition.

Methods

Mouse primary microglia with SPC were challenged by oxygen‐glucose deprivation (OGD) or lipopolysaccharide (LPS), and mice with SPC were subjected to middle cerebral artery occlusion (MCAO). Then, the mRNA and protein levels of pro‐inflammatory/anti‐inflammatory factors were analyzed. GSK‐3β phosphorylation and Nrf2 nuclear translocation were measured. The mRNA and protein expression of pro‐inflammatory/anti‐inflammatory factors, neurological scores, infarct volume, cellular apoptosis, the proportion of pro‐inflammatory/anti‐inflammatory microglia/macrophages, and the generation of super‐oxidants were examined after SPC or GSK‐3β inhibitor TDZD treatment with or without Nrf2 deficiency.

Results

Sevoflurane preconditioning promoted anti‐inflammatory and inhibited pro‐inflammatory microglia/macrophages phenotype both in vitro and in vivo. GSK‐3β phosphorylation at Ser9 was increased after SPC. Both SPC and TDZD administration enhanced Nrf2 nuclear translocation, reduced pro‐inflammatory microglia/macrophages markers expression, promoted anti‐inflammatory markers level, and elicited a neuroprotective effect. Nrf2 deficiency abolished the promoted anti‐inflammatory microglia/macrophages polarization and ischemic tolerance induced by TDZD treatment. The reduced percentage of pro‐inflammatory positive cells and super‐oxidants generation induced by SFC or TDZD was also reversed by Nrf2 knockdown.

Conclusions

Our results indicated that SPC exerts brain ischemic tolerance and promotes anti‐inflammatory microglia/macrophages polarization by GSK‐3β‐dependent Nrf2 activation, which provides a novel mechanism for SPC‐induced neuroprotection.

Protective effect of gamma-aminobutyric acid against oxidative stress by inducing phase II enzymes in C2C12 myoblast cells

In this study, the cytoprotective effect of gamma-aminobutyric acid (GABA) via inducing phase II enzymes in C2C12 myoblasts was evaluated. The highest concentration of GABA (100 μM) significantly increased the cell viability by approximately 90% in hydrogen peroxide-induced C2C12 cells. The treatment with GABA (100 μM) effectively decreased the glutathione (GSH) depletion and the activities of antioxidant enzymes such as catalase (CAT) and superoxide dismutase (SOD). And, reactive oxygen species (ROS) levels were effectively reduced by about 50% in GABA-treated cells. In addition, the protein expression of phase II enzymes, such as NADPH:quinone oxidoreductase 1 and heme oxygenase-1 was significantly increased by GABA treatment. Moreover, GABA treatment increased the nuclear factor erythroid 2-related factor 2 (Nrf2) protein expression in the nucleus of C2C12 myoblasts. Altogether, the results in this study indicate that GABA possesses the cytoprotective effects against oxidative insults by regulating the GSH levels, CAT and SOD activities, ROS scavenging activities, and expression of phase II enzymes through the activation of Nrf2 in C2C12 cells. Hence, this study suggests that the GABA supplementation could be effective in alleviating oxidative stress-induced muscle damage. PRACTICAL APPLICATIONS: GABA exists in the germ and bran layers of rice and is well-known as the inhibitory neurotransmitter in the central nervous system. GABA also has various health beneficial effects, such as preventing chronic alcohol-related diseases and lowering blood pressure. The present study shows the cytoprotective effect of GABA against oxidative stress in C2C12 myoblasts, and suggests that GABA has great potential as a functional food ingredient for attenuating oxidative stress-induced muscle damage.

Curcumin improves asthenozoospermia by inhibiting reactive oxygen species reproduction through nuclear factor erythroid 2-related factor 2 activation

We conducted this study for the purpose of evaluating the protective mechanisms of curcumin against oxidative stress in asthenozoospermic individuals. Asthenozoospermic individuals were grouped into AS group, curcumin treatment group and brusatol + curcumin treatment group. The sperm motility was measured by computer-aided sperm analysis. We conducted flow cytometry and spectrophotometry to assess the levels of reactive oxygen species (ROS) and malondialdehyde (MDA). Chlortetracycline (CTC) was used to examine the acrosomal reaction of spermatozoa. Also, Western blotting was carried to measure antioxidant gene Nrf2 (nuclear factor erythroid 2-related factor) expression level. As our results shown, treatment with curcumin significantly decreased ROS formation and MDA production, compared with spermatozoa of AS group; however, Nrf2 inhibitor, Brusatol, inhibited Nrf2 expression and sperm function. Our results have shown that curcumin might protect spermatozoa by regulating Nrf2 level.

Spiraea prunifolia var. simpliciflora Attenuates Oxidative Stress and Inflammatory Responses in a Murine Model of Lipopolysaccharide-Induced Acute Lung Injury and TNF-α-Stimulated NCI-H292 Cells

Spiraea prunifolia var. simpliciflora (SP) is traditionally used as an herbal remedy to treat fever, malaria, and emesis. This study aimed to evaluate the anti-oxidative and anti-inflammatory properties of the methanol extract of SP leaves in tumor necrosis factor (TNF)-α-stimulated NCI-H292 cells and in a lipopolysaccharide (LPS)-induced acute lung injury (ALI) mouse model. SP decreased the number of inflammatory cells and the levels of TNF-α, interleukin (IL)-1β, and IL-6 in the bronchoalveolar lavage fluid, and inflammatory cell infiltration in the lung tissues of SP-treated mice. In addition, SP significantly suppressed the mRNA and protein levels of TNF-α, IL-1β, and IL-6 in TNF-α-stimulated NCI-H292 cells. SP significantly suppressed the phosphorylation of the mitogen-activated protein kinases (MAPKs) and p65-nuclear factor-kappa B (NF-κB) in LPS-induced ALI mice and TNF-α-stimulated NCI-H292 cells. SP treatment enhanced the nuclear translocation of nuclear factor erythroid 2-related factor (Nrf2) with upregulated antioxidant enzymes and suppressed reactive oxygen species (ROS)-mediated oxidative stress in the lung tissues of LPS-induced ALI model and TNF-α-stimulated NCI-H292 cells. Collectively, SP effectively inhibited airway inflammation and ROS-mediated oxidative stress, which was closely related to its ability to induce activation of Nrf2 and inhibit the phosphorylation of MAPKs and NF-κB. These findings suggest that SP has therapeutic potential for the treatment of ALI.

The Regulation of NFE2L2 (NRF2) Signalling and Epithelial-to-Mesenchymal Transition in Age-Related Macular Degeneration Pathology

Age-related macular degeneration (AMD) is a mounting cause of loss of sight in the elderly in the developed countries, a trend enhanced by the continual ageing of the population. AMD is a multifactorial and only partly understood, malady. Unfortunately, there is no effective treatment for most AMD patients. It is known that oxidative stress (OS) damages the retinal pigment epithelium (RPE) and contributes to the progression of AMD. We review here the potential importance of two OS-related cellular systems in relation to AMD. First, the nuclear factor erythroid 2-related factor 2 (NFE2L2; NRF2)-mediated OS response signalling pathway is important in the prevention of oxidative damage and a failure of this system could be critical in the development of AMD. Second, epithelial-to-mesenchymal transition (EMT) represents a change in the cellular phenotype, which ultimately leads to the fibrosis encountered in RPE, a characteristic of AMD. Many of the pathways triggering EMT are promoted by OS. The possible interconnections between these two signalling routes are discussed here. From a broader perspective, the control of NFE2L2 and EMT as ways of preventing OS-derived cellular damage could be potentially valuable in the therapy of AMD.

Protective effects of HO-1 pathway on lung injury subsequent to limb ischemia reperfusion

Limb ischemia reperfusion (LIR) can activate endogenous cytoprotective mechanisms by generating specific proteins against reperfusion injury in remote organs. The present study investigated the roles of heme oxygenase-1 (HO-1) pathway and the molecular mechanisms underlying the regulation of this pathway on lung injury following LIR. LIR was induced by ischemia for 4 hours followed by reperfusion for 6 hours (LIR 6 hours) or 16 hours (LIR 16 hours) in male Sprague-Dawley rats. HO-1 inducer cobalt protoporphyrin (Copp) or HO-1 inhibitor zinc protoporphyrin (Znpp) was intravenously injected 24 hours before ischemia. The animals were randomly divided into nine groups, including normal control, LIR 6 hours, LIR 16 hours, Copp, Copp + LIR 6 hours, Copp + LIR 16 hours, and Znpp, Znpp+ LIR 6 hours, and Znpp + LIR 16 hours groups (each group included four samples). Lung injury was examined through histopathology. Quantitative real-time PCR, immunohistochemistry and Western blot were applied to detect the mRNA and protein levels of HO-1, Nrf2, and Bach1. Our study showed that LIR induced Nrf2 upregulation but Bach1 downregulation to promote HO-1 expression in lung tissues. Activation of HO-1 pathway by Copp potentially enhanced Nrf2 expression but inhibition of the pathway by Znpp promoted Bach1 expression. Inducer of HO-1 pathway, Copp injection improved the lung injury. Nevertheless, Znpp injection aggravated the lung injury following LIR. Our findings suggested that activated HO-1 pathway might exert protective effects on the lung injury following LIR.

4-Hydroxyphenylacetic Acid Prevents Acute APAP-Induced Liver Injury by Increasing Phase II and Antioxidant Enzymes in Mice

Acetaminophen (APAP) overdose is the principal cause of drug-induced acute liver failure. 4-hydroxyphenylacetic acid (4-HPA), a major microbiota-derived metabolite of polyphenols, is involved in the antioxidative action. This study seeks to investigate the ability of 4-HPA to protect against APAP-induced hepatotoxicity, as well as the putative mechanisms involved. Mice were treated with 4-HPA (6, 12, or 25 mg/kg) for 3 days, 1 h after the last administration of 4-HPA, a single dose of APAP was intraperitoneally infused for mice. APAP caused a remarkable increase of oxidative stress markers, peroxynitrite formation, and fewer activated phase II enzymes. 4-HPA increased Nrf2 translocation to the nucleus and enhanced the activity of phase II and antioxidant enzymes, and could thereby ameliorate APAP-induced liver injury. Studies reveal that 4-HPA, as an active area of bioactive dietary constituents, could protect the liver against APAP-induced injury, implying that 4-HPA could be a new promising strategy and natural hepatoprotective drug.

Bioavailable Blueberry-Derived Phenolic Acids at Physiological Concentrations Enhance Nrf2-Regulated Antioxidant Responses in Human Vascular Endothelial Cells

SCOPE

Blueberry consumption is believed to confer a cardiovascular health advantage, but the active compounds and effects require characterization. This study aims to identify the polyphenol metabolites in plasma after blueberry juice intake and determine their bioactivity on endothelial cells.

METHODS AND RESULTS

Three healthy individuals are recruited to obtain profiles of bioavailable plasma polyphenol metabolites following intake of blueberry juice. Of 33 phenolic compounds screened, 12 aglycone phenolic acids are detected and their maximum plasma concentrations and circulation time determined. Using this information, the effect of three physiologically relevant mixtures of blueberry-derived phenolic acids is investigated for their ability to induce nuclear factor erythroid 2-related factor 2 (Nrf2)-nuclear translocation and downstream gene expression in human endothelial cells. Pretreatment with the phenolic acids for 18 h results in a significant upregulation of the Nrf2-regulated antioxidant response proteins heme oxygenase 1 (HO-1) and glutamate-cysteine ligase modifier subunit (GCLM), following 6 h exposure to 2.5 μm H₂ O₂ .

CONCLUSION

Physiologically relevant concentrations of blueberry-derived aglycone phenolic acids can induce Nrf2-regulated antioxidant response proteins in vascular endothelial cells in response to low μm concentrations of H₂ O₂ . Our results represent an advance over previous studies that have used single compounds or high concentrations in cell-based investigations.

Fisetin Regulates Nrf2 Expression and the Inflammation-Related Signaling Pathway to Prevent UVB-Induced Skin Damage in Hairless Mice

Chronic ultraviolet (UV) exposure may cause skin damage, disrupt skin barrier function, and promote wrinkle formation. UV induces oxidative stress and inflammation, which results in extracellular matrix degradation in the dermis and epidermal hyperplasia. Our previous study demonstrated that fisetin exerts photoprotective activity by inhibiting mitogen-activated protein kinase/activator protein-1/matrix metalloproteinases (MMPs) activation. In this study, fisetin was applied topically to investigate its antiphotodamage effects in hairless mice. The erythema index (a* values) and transepidermal water loss were evaluated to assess skin damage, and immunohistochemical staining was conducted to elucidate the photoprotective mechanism of fisetin. The results revealed that the topical application of fisetin reduced UVB-induced increase in the a* value and wrinkle formation. In addition, fisetin inhibited epidermal hyperplasia and increased the collagen content in the dermis. Fisetin exerted photoprotective activity by inhibiting the expression of MMP-1, MMP-2, and cyclooxygenase-2 and increasing the expression of nuclear factor erythroid 2-related factor. Furthermore, fisetin increased the expression of filaggrin to prevent UVB-induced barrier function disruption. Altogether, the present results provide evidence of the effects and mechanisms of fisetin's antiphotodamage and antiphotoinflammation activities.

Oxidized casein impairs antioxidant defense system and induces hepatic and renal injury in mice

SCOPE

Oxidized protein products (OPPs) can be easily found in meat and milk during processing and storage. Evidence supports that accumulation of endogenous OPPs plays a negative role in physiological metabolism. However, the impacts of dietary OPPs and the mechanisms have not been elucidated yet. The present study evaluated whether oral oxidized casein would destruct the antioxidant defense system and cause potential oxidized injury in mice liver and kidney.

METHODS AND RESULTS

We performed oxidized casein (modified respectively by H2O2-Cu and HClO) feeding experiments using KM mice (20-22 g). A 10-weeks feeding of oxidized casein as basal protein caused oxidative stress by increasing protein carbonylation (PC), advanced oxidation protein products (AOPPs), dityrosine (Dityr), lipid peroxidation and ROS levels in mice liver, kidney and blood (P<0.05). In mice liver and kidney, the mRNA expression of Nrf2, γ-GCS, HO-1, GPX-3, and GPX-4 up-regulated, the protein level of Nrf2 in nucleus increased. However, activities of anti-oxidant enzymes (CAT, SOD, and GPX) decreased (P<0.05). Moreover, histopathological examination displayed the formation of fibrous septa in mice liver and kidney after oxidized casein feeding.

CONCLUSION

Oxidized casein impairs antioxidant defense system and induces hepatic and renal fibrosis.

Deferoxamine promotes osteoblastic differentiation in human periodontal ligament cells via the nuclear factor erythroid 2-related factor-mediated antioxidant signaling pathway

BACKGROUND AND OBJECTIVE

Recently it was reported that deferoxamine (DFO), an iron chelator, stimulates bone formation from MG63 and mesenchymal stem cells, but inhibits differentiation in rat calvarial cells; however, the effect of DFO on osteoblastic differentiation in human periodontal ligament cells (hPDLCs) has not been reported. The aim of this study was to investigate the effects and the possible underlying mechanism of DFO on osteoblastic differentiation of hPDLCs.

MATERIAL AND METHODS

The effect of DFO on osteoblast differentiation was determined by the staining intensity of calcium deposits with Alizarin red and by RT-PCR analysis of the expression of osteoblastic markers. Signal transduction pathways were analyzed by western blotting.

RESULTS

DFO increased osteogenic differentiation in a concentration-dependent manner by expression of the mRNA for differentiation markers and calcium nodule formation. Exposure of hPDLCs to DFO resulted in increases in the production of reactive oxygen species and in the levels of nuclear factor erythroid 2-related factor (Nrf2) protein in nuclear extractions, as well as a dose-dependent increase in the expression of Nrf2 target genes, including glutathione (GSH), glutathione S-transferase, γ-glutamylcysteine lygase, glutathione reductase and glutathione peroxidase. Pretreatment with Nrf2 small interfering RNA, GSH depletion by buthionine sulfoximine and diethyl maleate, and with antioxidants by N-acetylcysteine and vitamin E, blocked DFO-stimulated osteoblastic differentiation. Furthermore, pretreatment with GSH depletion and antioxidants blocked DFO-induced p38 MAPK, ERK, JNK and nuclear factor-kappaB pathways.

CONCLUSION

These data indicate, for the first time, that nontoxic DFO promotes osteoblastic differentiation of hPDLCs via modulation of the Nrf2-mediated antioxidant pathway.