Mate tea reduces high fat diet-induced liver and metabolic disorders in mice
High-fat diet (HFD)-induced obesity is a worldwide health problem and can cause lipid accumulation in the liver. We evaluated the hepatoprotective effect of mate tea treatment in mice submitted to an HFD. C57BL/6 mice were fed an HFD for 13 weeks with and without mate tea. A separate group of mice was treated with fenofibrate as a positive control (a regular drug for lipid disorders). Histological analyses, glucose tolerance tests (GTT), and quantification of mediators related to lipid peroxidation, oxidative stress and blood biomarkers for lipid profile were performed. The weight of animals and major organs related to hepatic steatosis was determined, and proinflammatory cytokines and the participation of the Nrf2 pathway and adiponectin were evaluated. Mate tea prevented the accumulation of lipid droplets in hepatocytes as well as weight gain in animals submitted to the HFD. Mate tea treatment also prevented increases in the liver weight, heart weight and amount of visceral and subcutaneous white adipose tissue. Mate tea was able to prevent the deregulation of glucose uptake, as evaluated by GTT, and improved the indicators of oxidative stress, such as nitrite levels, catalase activity, and oxidative damage, as evaluated by protein carbonylation and the MDA levels. Mate tea had an anti-inflammatory effect, preventing the increase of IL-1β and KC and upregulating the expression of Nrf2. Mate tea prevented insulin increase and HDL cholesterol decrease but did not affect total cholesterol or triglycerides levels. Treatment also prevented adiponectin increase. Mate tea may be a good resource to reduce hepatic steatosis in the future since it has anti-diabetic, anti-inflammatory and antioxidant effects, which prevent the accumulation of fat in the liver.
Inhibition of TREM1 reduces inflammation and oxidative stress after spinal cord injury (SCI) associated with HO-1 expressions
Spinal cord injury (SCI) is a devastating event, leading to the progression of chronic neuropathic pain syndrome. Triggering receptor expressed on myeloid cells 1 (TREM1) is an innate immune receptor expressed on neutrophils and monocytes/macrophages. TREM1 enhances inflammatory response in various models of diseases, but its significance in SCI remains unclear. In the present study, we attempted to explore the effects of TREM1 on the regulation of SCI. Spinal cord contusion injury was performed in wild type (WT) and TREM1-knockout (TREM1) mice, and real time-quantitative PCR (RT-qPCR), western blot, and immunofluorescent (IF) staining were used to calculate TREM1, inflammation and oxidative stress in spinal cord tissues 42 days after SPII. In vitro, astrocytes (AST) and BV2 cells were transfected TREM siRNA or the negative control (NC) siRNA to knockdown (KD) TREM1 expressions, followed by lipopolysaccharide (LPS) stimulation to verify the role od TREM1 in modulating SPI. The results suggested that TREM1 was highly expressed in the spinal cord tissues of WT mice after SCI. TREM mice exhibited improved locomotor function, mechanical and thermal hypersensitivity in the hindpaws after SCI. In addition, peripheral nerve injury-related biomarkers were down-regulated by TREM1 in SCI mice. TREM1 increased NeuN-stained cells, and decreased GFAP and Iba-1 expressions in spinal cord tissues of mice after SCI. TREM1 mice showed reduced expressions of inflammation-related regulators in the injured spinal cord. Further, toll like receptors (TLR-2, -3, -4, and -9), p-IκBα and p-nuclear factor-kappa B (NF-κB) protein expression levels were markedly decreased by TREM1 in mice after SCI injury. Moreover, TREM-deficiency suppressed oxidative stress markers, while enhanced anti-oxidants, such as superoxide dismutase-1 (SOD1), NAD(P)H:quinone oxidoreductase-1 (NQO-1), heme oxygenase-1 (HO-1) and nuclear factor E2-related factor 2 (Nrf2) in the injured spinal cord. The in vivo results mentioned above were verified in LPS-stimulated AST and BV2 cells in vitro. Of note, the in vitro results also demonstrated that suppressing HO-1 expressions using Zn-protoporphyrin (ZnPP) abrogated TREM1-reduced inflammation, oxidative stress and glial cells activation. The results above demonstrated that suppressing TREM1 expressions markedly improved the outcome of SCI, most likely through reducing inflammation and oxidative stress at least partly regulated by HO-1 expressions. TREM1 inhibition might be therefore has potential as a therapeutic target after SCI.
Apigetrin treatment attenuates LPS-induced acute otitis media though suppressing inflammation and oxidative stress
The natural course of otitis media in children is acute and self-limiting. Nevertheless, about 10-20% children could experience recurrent or persistent otitis media. Thus, finding effective candidate to prevent acute otitis media is urgently required. In our study, mouse acute otitis media model was constructed by lipopolysaccharide (LPS) injection into the middle ear of mice via the tympanic membrane. Apigetrin (APT) is a flavonoid isolated from various herbal medicines, possessing anti-inflammatory and anti-oxidative bioactivities. However, if APT could attenuate acute otitis media in LPS-induced animal models, little is to be known. Hematoxylin and eosin (H&E) staining suggested that APT treatment reduced LPS-induced higher mucosa thickness. LPS-triggered inflammatory response was also inhibited by APT, as evidenced by the down-regulated neutrophils and macrophages. Additionally, the reduced inflammatory factors, including interleukin-1β (IL-lβ), tumor necrosis factor α (TNF-α), IL-6 and vascular endothelial growth factor (VEGF) were observed in APT-treated mice with acute otitis media. The process was associated with the inhibition of toll-like receptor 4 (TLR4)/nuclear factor kappa B (NF-κB) pathway, which was proved by the blockage of TLR4, MyD88, p-IKKα, p-IκBα, and p-NF-κB using western blot analysis. Moreover, the production of reactive oxygen species (ROS) caused by LPS was also reduced by APT through promoting anti-oxidants, involving superoxide dismutase (SOD) activity, heme oxygenase-1 (HO-1), NADP(H) quinone oxidoreductase 1 (NQO-1) and nuclear factor erythroid 2-related factor 2 (Nrf2) expressions. In contrast, high levels of MDA and kelch-like ECH-associated protein 1 (Keap 1) in LPS-treated mice were down-regulated by APT, which might be associated with the inactivation of NF-κB. In vitro, APT exhibited anti-inflammatory and anti-oxidant effects with little cytotoxicity in LPS-stimulated cells. Together, the data above indicated that APT could ameliorate acute otitis media through inhibiting inflammation and oxidative stress.
Traditional Chinese medicine Gegen Qinlian decoction ameliorates irinotecan chemotherapy-induced gut toxicity in mice
Gegen Qinlian decoction (GQT), is a classic traditional Chinese medicine formula chronicled in Shang Han Lun, and is widely used to treat diarrhea and inflammation symptoms in various gastrointestinal disorders. Although it has been found to inhibit delayed-onset mice diarrhea resulted from irinotecan (CPT-11) administration in preliminary experiments, the underlying mechanisms and chemical components remain elusive.
Hydroxytyrosol supplementation ameliorates the metabolic disturbances in white adipose tissue from mice fed a high-fat diet through recovery of transcription factors Nrf2, SREBP-1c, PPAR-γ and NF-κB
White adipose tissue (WAT) have a relevant metabolic and inflammatory function, in overweight or obesity conditions. In this regard, the WAT under over feeding nutrition present a significant increment in oxidative stress, pro-inflammatory status and depletion of n-3 long chain polyunsaturated fatty acid. Hydroxytyrosol (HT) is a polyphenol with important cytoprotective effects, and this molecule can modulate the gene expression, transcription factors and enzymatic activity.
Blocking of tripartite motif 8 protects against lipopolysaccharide (LPS)-induced acute lung injury by regulating AMPKα activity
Acute lung injury (ALI) and its more serious form, respiratory distress syndrome (ARDS), are considered as an acute and severe inflammatory process existing in lungs, and still remain high mortality rates. Tripartite motif 8 (TRIM8) contains an N-terminal RING finger, which is followed by two B-boxes and a coiled-coil domain, belonging to the TRIM/RBCC family and playing significant role in meditating inflammation, oxidative stress and apoptosis. In the study, we investigated the role of TRIM8 in ALI induced by lipopolysaccharide (LPS) and the underlying molecular mechanisms. The in vitro results indicated that LPS time-dependently enhanced TRIM8 expression in lung epithelial cells. Suppressing TRIM8 markedly ameliorated LPS-elicited inflammatory response, as evidenced by the down-regulated mRNA levels of interleukin-1β (IL-1β), IL-6 and tumor necrosis factor-α (TNF-α) in cells mainly through inactivating nuclear factor-kappa B (NF-κB) signaling pathway; however, over-expressing TRIM8 markedly promoted inflammation in LPS-challenged cells. In addition, LPS-induced oxidative stress was accelerated by TRIM8 over-expression, while being alleviated by TRIM8 knockdown by regulating Nrf2 signaling. Importantly, TRIM8 could negatively meditate AMP-activated protein kinase-α (AMPKα) activation to modulate LPS-triggered inflammatory response and ROS generation in vitro. Additionally, our in vivo findings suggested that TRIM8 knockdown effectively attenuated LPS-induced lung injury nu decrease of lung wet/dry (W/T) ratio, protein concentrations, neutrophil infiltration, myeloperoxidase (MPO) activity, reactive oxygen species (ROS) production and superoxide dismutase (SOD) depletion. Meanwhile, the loss of TRIM8 markedly lessened IL-1β, IL-6 and TNF-α expression in lung tissues of LPS-challenged mice, and reduced NF-κB phosphorylation. Furthermore, TRIM8 knockdown evidently improved nuclear factor-erythroid 2 related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) expressions in lung of LPS-treated mice. The anti-inflammation and anti-oxidant role of TRIM8-silence might be associated with AMPKα phosphorylation. Together, our study firstly provided a support that TRIM8 knockdown effectively protected LPS-induced ALI against inflammation and oxidative stress largely dependent on the promotion of AMPKα pathway.
Sulforaphane enriched transcriptome of lung mitochondrial energy metabolism and provided pulmonary injury protection via Nrf2 in mice
Nrf2 is essential to antioxidant response element (ARE)-mediated host defense. Sulforaphane (SFN) is a phytochemical antioxidant known to affect multiple cellular targets including Nrf2-ARE pathway in chemoprevention. However, the role of SFN in non-malignant airway disorders remain unclear. To test if pre-activation of Nrf2-ARE signaling protects lungs from oxidant-induced acute injury, wild-type (Nrf2) and Nrf2-deficient (Nrf2) mice were given SFN orally or as standardized broccoli sprout extract diet (SBE) before hyperoxia or air exposure. Hyperoxia-induced pulmonary injury and oxidation indices were significantly reduced by SFN or SBE in Nrf2 mice but not in Nrf2 mice. SFN upregulated a large cluster of basal lung genes that are involved in mitochondrial oxidative phosphorylation, energy metabolism, and cardiovascular protection only in Nrf2 mice. Bioinformatic analysis elucidated ARE-like motifs on these genes. Transcript abundance of the mitochondrial machinery genes remained significantly higher after hyperoxia exposure in SFN-treated Nrf2 mice than in SFN-treated Nrf2 mice. Nuclear factor-κB was suggested to be a central molecule in transcriptome networks affected by SFN. Minor improvement of hyperoxia-caused lung histopathology and neutrophilia by SFN in Nrf2 mice implies Nrf2-independent or alternate effector mechanisms. In conclusion, SFN is suggested to be as a preventive intervention in a preclinical model of acute lung injury by linking mitochondria and Nrf2. Administration of SFN alleviated acute lung injury-like pathogenesis in a Nrf2-dependent manner. Potential AREs in the SFN-inducible transcriptome for mitochondria bioenergetics provided a new insight into the downstream mechanisms of Nrf2-mediated pulmonary protection.
Molecular hydrogen (H2): Potential in mitigating oxidative stress-induced cardiotoxicity
Uncontrolled production of oxygen and nitrogen radicals results in oxidative (OS) and nitrosative (NS) stresses that impair cellular functions and have been regarded as causative common denominators of many pathological processes. In this review, we report on the beneficial effects of molecular hydrogen (H2) in scavenging radicals in an artificial system of ●OH formation. As a proof of principle, we also demonstrate that in rat hearts in vivo, administration of H2 led to a significant increase in SOD as well as pAKT, a cell survival signaling molecule. Irradiation of the rats caused a significant increase in lipid peroxidation which was mitigated by pre-treatment of the animals with molecular H2. The nuclear factor erythroid 2-related factor 2 (Nrf2) is regarded as an important regulator of oxyradical homeostasis as well as it supports the functional integrity of cells, particularly under conditions of OS. We suggest that the beneficial effects of H2 may be through the activation of Nrf2 pathway that promotes innate antioxidants and reduction of apoptosis as well as inflammation.
Lotus seed skin proanthocyanidin extract exhibits potent antioxidant property via activation of the Nrf2-ARE pathway
Lotus seed is well known as traditional food and medicine, but its skin is usually discarded. Recent studies have shown that lotus seed skin contains a high concentration of proanthocyanidins that have multi-functions, such as antioxidation, anti-inflammation, and anti-cancer effects. In the present study, we aimed to isolate and purify the proanthocyanidins from lotus seed skin by acetone extraction and rotary evaporation, identify their chemical structures by HPLC-MS-MS and NMR, and further investigate the antioxidant properties of the extract purified by macroporous resin (PMR) from lotus seed skin both in vitro and in vivo. The results showed that PMR mainly contained oligomeric proanthocyanidins, especially dimeric procyanidin B1 (PB1), procyanidin B2 and procyanidin B4. Although it had limited ability to directly scavenge radicals in vitro, PMR could significantly enhance the expressions of antioxidant proteins via activation of nuclear factor-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway in HepG2 cells. Molecular data revealed that PB1, a major component in PMR, stabilized Nrf2 by inhibiting the ubiquitination of Nrf2, which led to subsequent activation of the Nrf2-ARE pathway, including the enhancements of Nrf2 nuclear translocation, Nrf2-ARE binding and ARE transcriptional activity. Moreover, the in vivo results in high fat diet-induced mice further verified the powerful antioxidant property of PMR. These results revealed that lotus seed skin is a promising resource for functional food development.
Hepatoprotective effect of chiisanoside from Acanthopanax sessiliflorus against LPS/D-GalN-induced acute liver injury by inhibiting NF-κB and activating Nrf2/HO-1 signaling pathways
In China, Acanthopanax sessiliflorus is a delicious wild vegetable. It is also used to treat of inflammation and pain. Considering that chiisanoside (CSS) is the main constituent of the leaf of A. sessiliflorus. Combined use of LPS/D-GalN can induce acute liver failure like human beings, and there are no reports on the protective effect of CSS against LPS/D-GalN-induced acute liver injury in mice.
Molecular mechanism involved in cyclophosphamide-induced cardiotoxicity: Old drug with a new vision
Cyclophosphamide (CP) is an important anticancer drug which belongs to the class of alkylating agent. Cyclophosphamide is mostly used in bone marrow transplantation, rheumatoid arthritis, lupus erythematosus, multiple sclerosis, neuroblastoma and other types of cancer. Dose-related cardiotoxicity is a limiting factor for its use. CP-induced cardiotoxicity ranges from 7 to 28% and mortality ranges from 11 to 43% at the therapeutic dose of 170-180 mg/kg, i.v. CP undergoes hepatic metabolism that results in the production of aldophosphamide. Aldophosphamide decomposes into phosphoramide mustard & acrolein. Phosphoramide is an active neoplastic agent, and acrolein is a toxic metabolite which acts on the myocardium and endothelial cells. This is the first review article that talks about cyclophosphamide-induced cardiotoxicity and the different signaling pathways involved in its pathogenicity. Based on the available literature, CP is accountable for cardiomyocytes energy pool alteration by affecting the heart fatty acid binding proteins (H-FABP).CP has been found associated with cardiomyocytes apoptosis, inflammation, endothelial dysfunction, calcium dysregulation, endoplasmic reticulum damage, and mitochondrial damage. Molecular mechanism of cardiotoxicity has been discussed in detail through crosstalk of Nrf2/ARE, Akt/GSK-3β/NFAT/calcineurin, p53/p38MAPK, NF-kB/TLR-4, and Phospholamban/SERCA-2a signaling pathway. Based on the available literature we support the fact that metabolites of CP are responsible for cardiotoxicity due to depletion of antioxidants/ATP level, altered contractility, damaged endothelium and enhanced pro-inflammatory/pro-apoptotic activities resulting into cardiomyopathy, myocardial infarction, and heart failure. Dose adjustment, elimination/excretion of acrolein and maintenance of endogenous antioxidant pool could be the therapeutic approach to mitigate the toxicities.
Melatonin receptor activation provides cerebral protection after traumatic brain injury by mitigating oxidative stress and inflammation via the Nrf2 signaling pathway
Traumatic brain injury (TBI) is a principal cause of death and disability worldwide. Melatonin, a hormone made by the pineal gland, is known to have anti-inflammatory and antioxidant properties. In this study, using a weight-drop model of TBI, we investigated the protective effects of ramelteon, a melatonin MT1/MT2 receptor agonist, and its underlying mechanisms of action. Administration of ramelteon (10mg/kg) daily at 10:00 am alleviated TBI-induced early brain damage on day 3 and long-term neurobehavioral deficits on day 28 in C57BL/6 mice. Ramelteon also increased the protein levels of interleukin (IL)-10, IL-4, superoxide dismutase (SOD), glutathione, and glutathione peroxidase and reduced the protein levels of IL-1β, tumor necrosis factor, and malondialdehyde in brain tissue and serum on days 1, 3, and 7 post-TBI. Similarly, ramelteon attenuated microglial and astrocyte activation in the perilesional cortex on day 3. Furthermore, ramelteon decreased Keap 1 expression, promoted nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear accumulation, and increased levels of downstream proteins, including SOD-1, heme oxygenase-1, and NQO1 on day 3 post-TBI. However, in Nrf2 knockout mice with TBI, ramelteon did not decrease the lesion volume, neuronal degeneration, or myelin loss on day 3; nor did it mitigate depression-like behavior or most motor behavior deficits on day 28. Thus, timed ramelteon treatment appears to prevent inflammation and oxidative stress via the Nrf2-antioxidant response element pathway and might represent a potential chronotherapeutic strategy for treating TBI.
(Gaertn.) Roxb. Extract and Gallic Acid Attenuate LPS-Induced Inflammation and Oxidative Stress via MAPK/NF-B and Akt/AMPK/Nrf2 Pathways
Excessive oxidative stress plays a critical role in the progression of various diseases. Recently, we showed that (Gaertn.) Roxb. extract (TBE) inhibits inflammatory response and reactive oxygen species (ROS) production in THP-1 macrophages. However, molecular mechanisms underlying anti-inflammatory and antioxidant activities of TBE and its major polyphenolic compounds gallic acid (GA) and ellagic acid (EA) remain unclear. We found that TBE and GA attenuated LPS-induced inflammatory mediator expression, ROS production, and activation of mitogen-activated protein kinase (MAPK) and nuclear factor-kappa B (NF-B) in RAW 264 macrophages. Furthermore, TBE and GA increased antioxidant enzyme expression along with upstream mediators nuclear factor erythroid-2-related factor 2 (Nrf2), Akt, and AMP-activated protein kinase (AMPK). Importantly, knockdown of Nrf2 by siRNA and specific inhibition of Akt and AMPK significantly reduced antioxidant enzyme expression induced by TBE and GA. Finally, effects on histopathology and gene expression were assessed in tissues collected after intraperitoneal injection of LPS with or without TBE treatment. TBE enhanced antioxidant enzyme expression and improved acute kidney injury in LPS-shock model mice. In conclusion, TBE and GA exert protective effects against inflammation and oxidative stress by suppressing MAPK/NF-B pathway and by activating Akt/AMPK/Nrf2 pathway. These results suggest that TBE and GA might be effective for the treatment of inflammation-related diseases.
Protective Role of Nuclear Factor-Erythroid 2-Related Factor 2 Against Radiation-Induced Lung Injury and Inflammation
Radiation-induced lung injury (RILI) is one of the most common and fatal complications of thoracic radiotherapy. Inflammatory cell infiltration, imbalance of inflammatory cytokines, and oxidative damage were reported to be involved during RILI pathogenesis, especially in the early phase of RILI. Nuclear factor-erythroid 2-related factor 2 (Nrf2) is a key transcriptional regulator of antioxidative cascades, and regulates life span of mice after administration of thoracic irradiation. We investigated the effects of Nrf2 on RILI and inflammation using Nrf2-knockout, Nrf2-overexpression and wild-type mice with or without 15 Gy ionizing radiation to thorax. Our results showed that Nrf2 deficiency aggravated radiation-induced histopathological changes, macrophage and neutrophil infiltration, serum levels of pro-inflammatory cytokines (IL-6, MCP-1, IFN-γ, TNF, and IL-12p70), and the levels of peroxidation products in the mouse lung. Moreover, loss of Nrf2 reduced radiation-induced serum levels of anti-inflammatory cytokine, IL-10, and antioxidative proteins. Nrf2 overexpression significantly alleviated radiation-induced histopathological changes, macrophages and neutrophils infiltration, serum levels of pro-inflammatory cytokines, and the levels of peroxidation products in lung tissues. Nrf2 overexpression also increased the serum levels of IL-10 and antioxidative proteins. These results indicated that Nrf2 had a protective role against radiation-induced acute lung injury and inflammation, and that antioxidative therapy might be a promising treatment for RILI.
DC32, a Dihydroartemisinin Derivative, Ameliorates Collagen-Induced Arthritis Through an Nrf2-p62-Keap1 Feedback Loop
Artemisinins have been reported to have diverse functions, such as antimalaria, anticancer, anti-inflammation, and immunoregulation activities. DC32 [(9α,12α-dihydroartemisinyl) bis(2'-chlorocinnmate)], a dihydroartemisinin derivative possessing potent immunosuppressive properties, was synthesized in our previous study. Collagen-induced arthritis (CIA) in DBA/1 mice and inflammatory model in NIH-3T3 cells were established to evaluate the effect of DC32 on RA and discover the underlying mechanisms. The results showed that DC32 could markedly alleviate footpad inflammation, reduce cartilage degradation, activate the Nrf2/HO-1 signaling pathway, and increase the transcription of p62 in DBA/1 mice with CIA. Further mechanistic exploration with NIH-3T3 cells indicated that DC32 could increase the transcription, expression, and nuclear translocation of Nrf2. In addition, DC32 promoted degradation of Keap1 protein and upregulated HO-1 and p62 expression. Furthermore, the effect of DC32 on Keap1 degradation could be prevented by p62 knockdown using siRNA. Administration of DC32 could inhibit the activation of Akt/mTOR and ERK, and pretreatment of NIH-3T3 cells with the autophagy inhibitor 3-methyladenine (3-MA) attenuated the degradation of Keap1 induced by DC32. These results suggest that DC32 inhibits the degradation of Nrf2 by promoting p62-mediated selective autophagy and that p62 upregulation contributed to a positive feedback loop for persistent activation of Nrf2. In summary, our present study demonstrated that DC32 significantly suppressed rheumatoid arthritis (RA) via the Nrf2-p62-Keap1 feedback loop by increasing the mRNA and protein levels of Nrf2 and inducing p62 expression. These findings provide new mechanisms for artemisinins in RA treatment and a potential strategy for discovering antirheumatic drugs.