Protective Effect of Isoliquiritigenin against Ethanol-Induced Hepatic Steatosis by Regulating the SIRT1-AMPK Pathway

Melosira nummuloides Ethanol Extract Ameliorates Alcohol-Induced Liver Injury by Affecting Metabolic Pathways

Melosira nummuloides is a microalga with a nutritionally favorable polyunsaturated fatty acid profile. In the present study, M. nummuloides ethanol extract (MNE) was administered to chronic-binge alcohol-fed mice and alcohol-treated HepG2 cells, and its hepatoprotective effects and underlying mechanisms were investigated. MNE administration reduced triglyceride (TG), total cholesterol (T-CHO), and liver injury markers, including aspartate transaminase (AST) and alanine transaminase (ALT), in the serum of chronic-binge alcohol-fed mice. However, MNE administration increased the levels of phosphorylated adenosine monophosphate-activated protein kinase (P-AMPK/AMPK) and PPARα, which was accompanied by a decrease in SREBP-1; this indicates that MNE can inhibit adipogenesis and improve fatty acid oxidation. Moreover, MNE administration upregulated the expression of antioxidant enzymes, including SOD, NAD(P)H quinone dehydrogenase 1, and GPX, and ameliorated alcohol-induced inflammation by repressing the Akt/NFκB/COX-2 pathway. Metabolomic analysis revealed that MNE treatment modulated many lipid metabolites in alcohol-treated HepG2 cells. Our study findings provide evidence for the efficacy and mechanisms of MNE in ameliorating alcohol-induced liver injury.

Identification of α-amanitin effector proteins in hepatocytes by limited proteolysis-coupled mass spectrometry

The misuse of poisonous mushrooms containing amatoxins causes acute liver failure (ALF) in patients and is a cause of significant mortality. Although the toxic mechanisms of α-amanitin (α-AMA) and its interactions with RNA polymerase II (RNAP II) have been studied, α-AMA effector proteins that can interact with α-AMA in hepatocytes have not been systematically studied. Limited proteolysis-coupled mass spectrometry (LiP-MS) is an advanced technology that can quickly identify protein-ligand interactions based on global comparative proteomics. This study identified the α-AMA effector proteins found in human hepatocytes, following the detection of conformotypic peptides using LiP-MS coupled with tandem mass tag (TMT) technology. Proteins that are classified into protein processing in the endoplasmic reticulum and the ribosome during the KEGG pathway can be identified through affinity evaluation, according to α-AMA concentration-dependent LiP-MS and LiP-MS in hepatocytes derived from humans and mice, respectively. The possibility of interaction between α-AMA and proteins containing conformotypic peptides was evaluated through molecular docking studies. The results of this study suggest a novel path for α-AMA to induce hepatotoxicity through interactions with various proteins involved in protein synthesis, as well as with RNAP II.

AXL is required for hypoxia-mediated hypoxia-inducible factor-1 alpha function in glioblastoma

Glioblastoma (GBM) is the most aggressive type of central nervous system tumor. Molecular targeting may be important when developing efficient GBM treatment strategies. Sequencing of GBMs revealed that the receptor tyrosine kinase (RTK)/RAS/phosphatidylinositol-3-kinase pathway was altered in 88% of samples. Interestingly, AXL, a member of RTK, was proposed as a promising target in glioma therapy. However, the molecular mechanism of AXL modulation of GBM genesis and proliferation is still unclear. In this study, we investigated the expression and localization of hypoxia-inducible factor-1 alpha (HIF-1α) by AXL in GBM. Both AXL mRNA and protein are overexpressed in GBM. Short-interfering RNA knockdown of AXL in U251-MG cells reduced viability and migration. However, serum withdrawal reduced AXL expression, abolishing the effect on viability. AXL is also involved in hypoxia regulation. In hypoxic conditions, the reduction of AXL decreased the level and nuclear localization of HIF-1α. The co-expression of HIF-1α and AXL was found in human GBM samples but not normal tissue. This finding suggests a mechanism for GBM proliferation and indicates that targeting AXL may be a potential GBM therapeutic.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00195-z.

Cheong-sang-bang-pung-san alleviated hepatic lipid accumulation by regulating lipid metabolism in vitro and in vivo

Introduction: The occurrence of fatty liver disease, resulting from the accumulation of excessive fat within the liver, has been showing a significant and rapid increase. This study aimed to evaluate the therapeutic effects of Cheong-sang-bang-pung-san extract (CB) on fatty liver disease, and to elucidate the underlying mechanisms. Methods: We used a high-fat diet (HFD)-fed fatty liver mice and free fatty acid (FFA) induced HepG2 cell lipid accumulation model. The levels of serum, hepatic, and intracellular lipid content were assessed. Histopathological staining was used to evaluate the extent of hepatic lipid accumulation. Real-time polymerase chain reaction and Western blotting were conducted to examine the expression of factors associated with lipid metabolism. Results: We demonstrated that treatment with CB dramatically reduced body weight, liver weight, and fat mass, and improved the serum and hepatic lipid profiles in HFD-induced fatty liver mice. Additionally, CB alleviated lipid accumulation in HFD-fed mice by controlling lipid metabolism, including fatty acid uptake, triglyceride and cholesterol synthesis, and fatty acid oxidation, at the mRNA as well as protein levels. In free fatty acid-treated HepG2 cells, CB significantly reduced intracellular lipid accumulation by regulating lipid metabolism via the activation of AMP-activated protein kinase. Conclusion: These findings provide insights into the mechanisms underlying CB's effects on liver steatosis and position of CB as a potential therapeutic candidate for managing lipid metabolic disorders.

Glycyrrhizae Radix et Rhizoma: The popular occurrence of herbal medicine applied in classical prescriptions

Glycyrrhizae Radix et Rhizoma is a well-known herbal medicine with a wide range of pharmacological functions that has been used throughout Chinese history. This review presents a comprehensive introduction to this herb and its classical prescriptions. The article discusses the resources and distribution of species, methods of authentication and determination chemical composition, quality control of the original plants and herbal medicines, dosages use, common classical prescriptions, indications, and relevant mechanisms of the active content. Pharmacokinetic parameters, toxicity tests, clinical trials, and patent applications are discussed. The review will provide a good starting point for the research and development of classical prescriptions to develop herbal medicines for clinical use.

Humulus japonicus Extract Ameliorates Hepatic Steatosis Through the PPARα-Mediated Suppression of Alcohol-Induced Oxidative Stress

Humulus japonicus has been used to treat obesity, hypertension, and nonalcoholic fatty liver and to alleviate inflammation and oxidative stress. In the present study, we aimed to investigate the effects of H. japonicus ethanol extracts (HE) and luteolin 7-O-β-d-glucoside (LU), which is identified as a major active component of H. japonicus, on ethanol-induced oxidative stress and lipid accumulation in primary hepatocytes. Mouse primary hepatocytes were treated with HE and stimulated with ethanol. The MTT test was used to determine cell viability. By using Western blotting, the effects of HE on the expression of different proteins were investigated. Experimental mice were given a 5% alcohol liquid Lieber-DeCarli diet to induce alcoholic fatty liver. We found that both HE and LU individually attenuated ethanol-induced lipid accumulation, lipogenic protein expression, and cellular oxidative stress in hepatocytes. Treatment with HE or LU increased PPARα and SOD1 expression and catalase activity in a dose-dependent manner. Small interfering RNA of PPARα reduced the effects of HE on oxidative stress, lipid metabolism, and levels of antioxidants. We also observed that orally administered HE treatment alleviated hepatic steatosis in a diet containing ethanol-fed mice. This study suggests HE as a functional food that can improve hepatic steatosis, thereby preventing hepatic injury caused by alcohol consumption.

Inhibitory Effect of Isoliquiritigenin in Niemann-Pick C1-Like 1-Mediated Cholesterol Uptake

Isoliquiritigenin (ISL) is a flavonoid with a chalcone structure extracted from the natural herb Glycyrrhiza glabra. Its anti-inflammatory, antibacterial, antioxidant, and anticancer activities have been extensively studied. Moreover, ISL also possess hypolipidemic and atherosclerosis-reducing effects. However, its cholesterol-lowering mechanisms have not been reported yet. Niemann Pick C1 Like 1 (NPC1L1) is a specific transporter of cholesterol uptake. In this study, we found for the first time that ISL downregulates NPC1L1 expression and competitively inhibits cellular cholesterol uptake by binding to NPC1L1 in a concentration-dependent manner in vitro. This study provides a theoretical basis for further investigation of the molecular mechanisms of its cholesterol-lowering effect in vivo and inspired emerging drug research for cholesterol-lowering purposes through NPC1L1 inhibition.

Liquorice root extract and isoliquiritigenin attenuate high-fat diet-induced hepatic steatosis and damage in rats by regulating AMPK

Objective: This study compared the ability of Liquorice roots aqueous extract (LRE) and its ingredient, isoliquiritigenin (ISL), in alleviating high-fat diet (HFD)-induced hepatic steatosis and examined if this effect involves activation of AMPK.Materials and methods: Control or HFD-fed rats were treated with the vehicle, LRE (200 mg/kg), or ISL (30 mg/kg) for 8 weeks orally.Results: ISL and LRE reduced HFD-induced hyperglycaemia, improved liver structure, lowered serum and hepatic lipids, and attenuated hepatic oxidative stress and inflammation. In the control and HFD-fed rats, ISL and LRE significantly stimulated the muscular and hepatic mRNA and protein levels of AMPK, improved oral glucose tolerance, reduced hepatic mRNA levels of SREBP1/2, and upregulated hepatic levels of PPARα and Bcl2. These effects were comparable for ISL and LRE and were prevented by co-administration of compound C, an AMPK inhibitor.Discussion and conclusion: ISL and LRE provide an effective theory to alleviate hepatic steatosis through activating AMPK.

Isoliquiritigenin alleviates liver fibrosis through caveolin-1-mediated hepatic stellate cells ferroptosis in zebrafish and mice

BACKGROUND

Liver fibrosis is a major disease that threatens people's health around the world. However, there is a lack of effective treatment to completely reverse liver fibrosis. Liver transplantation is currently the only curative option for patients with advanced cirrhosis. Ferroptosis is a newly discovered type of cell death and plays an important role in the process of liver fibrosis, but the specific mechanism needs to be clarified.

HYPOTHESIS/PURPOSE

To explore the regulatory mechanism of isoliquiritigenin (ISL) in the process of liver fibrosis and the relationship between Cav-1 and ferroptosis.

METHODS

In this research, zebrafish, HSC-T6 cells, and mice were used as the research object. Different ROS probes to visually detect the content and distribution of ROS in live zebrafish and cells. Lentivirus and siRNA-mediated transfection techniques were used for the construction of Cav-1 overexpression and knockdown cell lines to verify the important role of Cav-1 in vitro.

RESULTS

Generally, we first elucidated that ISL relieved liver fibrosis by inducing hepatic stellate cells (HSCs) ferroptosis through repressing GPX4 expression and increasing the expression of TFR and DMT1, thus producing a large number of ROS, we also found that Cav-1 exerted its anti-hepatic fibrosis effect by promoting HSCs ferroptosis.

CONCLUSION

Our results have shown that Cav-1-mediated HSCs ferroptosis is necessary for ISL to play an anti-fibrotic effect in vitro and in vivo.

Hepatoprotective effect of Trigonella foenum graecum against ethanol-induced cell death in human liver cells (HepG2 and Huh7)

BACKGROUND

The plant Trigonella foenum graecum, also known as fenugreek, has been shown to have anticancer, antidiabetic, anti-inflammatory, and antioxidant properties. In this study, the hepatoprotective effect of fenugreek seed extract (FSE) against ethanol-induced cell death was investigated in human liver cells (HepG2 and Huh7).

METHODS AND RESULTS

The cytotoxic effect of FSE and ethanol on cells was evaluated by exposing the cells at different concentrations. Following that, the cells were pre-incubated with 5-25 μg/ml FSE, followed by a cytotoxic concentration (0.5 mM) of ethanol. MTT and neutral red uptake assays were performed in treated cells to assess the ability of FSE to protect cells from the cytotoxic effects of ethanol. When compared to controls, ethanol treatment significantly reduced the viability of HepG2 and Huh7 cells and altered the cell morphology, whereas treatment with FSE significantly increased cell viability and reversed ethanol-induced morphological changes. Furthermore, pretreatment with FSE dose-dependently reduced lactate dehydrogenate (LDH) leakage, lipid peroxidation (LPO) level, and catalase activities while increasing glutathione (GSH) level induced by ethanol. Pretreatment with FSE also reduced the generation of reactive oxygen species (ROS), caspase enzyme activities, and protein expression of caspase-3 and -9. In HepG2 cells, ethanol-induced apoptosis was observed, whereas FSE treatment reduced apoptosis by downregulating the expression of pro-apoptotic marker genes and upregulating the antiapoptotic gene.

CONCLUSIONS

In conclusion, this study reports on the mechanistic details of the hepatoprotective potential of FSE. The results also suggest that fenugreek seeds may be useful in preventing liver diseases caused by toxicants such as ethanol.

Astragaloside alleviates alcoholic fatty liver disease by suppressing oxidative stress

Alcoholic fatty liver disease (AFLD) is the most common liver disease and can progress to fatal liver cirrhosis and carcinoma, affecting millions of patients worldwide. The functions of astragaloside on the cardiovascular system have been elucidated. However, its role in AFLD is unclear. Ethanol-treated AML-12 cells were used as a cell model of alcoholic fatty liver. Real-time quantitative reverse transcription-PCR and Western blotting detected genes and proteins expressions. Reactive oxygen species (ROS), triglyceride, total cholesterol, low-density lipoprotein, albumin, ferritin, bilirubin, superoxide dismutase, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) were examined using commercial kits. Lipid accumulation was assessed by Oil red O staining. MTT and flow cytometry measured cell viability and apoptosis. JC-1 was used to analyze mitochondrial membrane potential. A rat model of AFLD was established by treating rats with ethanol. Astragaloside suppressed ethanol-induced lipid accumulation, oxidative stress, and the production of AST and ALT in AML-12 cells. Ethanol induced TNF-α and reduced IL-10 expression, which were reversed by astragaloside. Ethanol promoted Bax expression and cytochrome C release and inhibited Bcl-2 and ATP expression. Astragaloside hampered these apoptosis effects in AML-12 cells. Impaired mitochondrial membrane potential was recovered by astragaloside. However, all these astragaloside-mediated beneficial effects were abolished by the ROS inducer pyocyanin. Ethanol-induced activation of NF-κB signaling was suppressed by astragaloside in vitro and in vivo, suggesting that astragaloside inhibited oxidative stress by suppressing the activation of NF-κB signaling, thus improving liver function and alleviating AFLD in rats. Our study elucidates the pharmacological mechanism of astragaloside and provides potential therapeutic strategies for AFLD.

Tricoumaroylspermidine from rose exhibits inhibitory activity against ethanol-induced apoptosis in HepG2 cells

Hepatocyte apoptosis is involved in the pathogenesis of alcohol-associated liver disease (ALD) and anti-apoptotic agents/extracts are thereby of great importance in the prevention/treatment of ALD. In this study, the protective effects of 10 edible flowers against ethanol-induced cell death were investigated in HepG2 cells, with rose (Rosa rugosa) showing the strongest activity. Therefore, rose was chosen for further separation and purification of bioactive fractions. A special fraction, SLs, was found to significantly increase the viability of EtOH-treated cells and attenuated EtOH-induced apoptosis partially via the activation of the AMPK/SIRT1 signaling pathway. Chromatographic analysis identified a series of hydroxycinnamic acid amides, kaempferol glycosides, and quercetin glycosides in this fraction, while the following intracellular uptake and cytotoxicity studies revealed that N1,N5,N10-(E)-tri-p-coumaroylspermidine (a hydroxycinnamic acid amide) in this fraction exhibited remarkable hepatoprotective activity with similar effective dosage to sulforaphane. Hence, our results highlighted the anti-alcohol and hepatoprotective benefits of consuming rose.

Perspectives on the Role of Isoliquiritigenin in Cancer

Isoliquiritigenin (2',4',4-trihydroxychalcone, ISL), one of the most important bioactive compounds with a chalcone structure, is derived from licorice root. Licorice is commonly known as Glycyrrhiza, including Glycyrrhiza uralensis, Glycyrrhiza radix, and Glycyrrhiza glabra, which are generally available in common foods and Chinese herbal medicines based on a wide variety of biological functions and pharmacological effects, and its derivative (ISL) is utilized as a food additive and adjunct disease treatment. In this review, we summarized the progress over the last 10 years in the targeted pathways and molecular mechanisms of ISL that are involved in the regulation of the onset and progression of different types of cancers.

Isoliquiritigenin downregulates miR-195 and attenuates oxidative stress and inflammation in STZ-induced retinal injury

Diabetic retinopathy (DR) is a major microvascular complication of diabetes mellitus that leads to significant vision loss. Isoliquiritigenin (ISL) is a bioactive flavonoid found in the root of licorice with reported anti-oxidant and anti-inflammatory activities. In the present study, we evaluated the effect of ISL administration on diabetes-induced retinal injury. Diabetes was induced in male Sprague-Dawley rats using single intraperitoneal streptozotocin (STZ, 50 mg/kg) injection. Diabetic rats showed up-regulated retinal miR-195, reduced retinal levels of SIRT-1, and increased levels of oxidative stress, nuclear factor-κB (NF-κB), inflammatory cytokines, and endothelin-1. Moreover, histopathological and electron microscopy studies revealed distorted retinal layers and reduced number of ganglion cells. Oral administration of ISL (20 mg/kg/day) to diabetic rats for 8 weeks improved diabetes-induced retinal injury via down-regulation of miR-195, restoration of retinal SIRT-1 level, attenuation of oxidative stress, inflammation, and endothelial damage as well as preservation of retinal normal histology and ultrastructure. In conclusion, our results showed that ISL could be a promising therapeutic intervention to prevent the development and progression of DR. It also suggested that the miR-195/SIRT-1/NF-κB pathway may contribute to ISL treatment-induced beneficial effects.

Solid-State Fermentation of Aspergillus niger to Optimize Extraction Process of Isoliquiritigenin from Glycyrrhiza uralensis

We successfully extracted isoliquiritigenin from Glycyrrhiza uralensis via fermentation with Aspergillus niger and ultrasonic-assisted extraction. In brief, we used A. niger fermentation to culture G. uralensis powder, and we optimized some key parameters such as reaction conditions of pH, inoculation concentration of A. niger, fermentation time, and solid-liquid ratio. Based on a single-factor experiment, we utilized the response surface methodology (RSM) approach to optimize this extraction procedure. Using the RSM approach, optimized conditions of pH = 3.694, the solid-liquid ratio = 1 : 2.155, and the inoculation concentration of A. niger = 1466745 were selected. Optimized conditions resulted in an extraction efficiency of 1.525 mg/g. These results showed that the extraction of isoliquiritigenin was most affected by pH and then the time of fermentation and the solid-liquid ratio. Overall, the developed extraction technique yielded 5 times the amount of isoliquiritigenin when compared to traditional methods.

Alpha-Methylacyl-CoA Racemase (AMACR), a Potential New Biomarker for Glioblastoma

Alpha-Methylacyl-CoA racemase (AMACR), which was initially discovered as a prostate cancer marker, is critical for the chiral inversion mechanism of branched-chain fatty acids. However, the function of AMACR in brain tumors has not been investigated. In this study, AMACR appeared to be involved in glioblastoma. The protein and mRNA levels of AMACR were highly elevated in glioblastoma. Downregulation of AMACR inhibited cell proliferation. Comprehensive analysis of the public REMBRANDT GBM dataset also confirmed that the level of AMACR expression was correlated with the clinical prognosis of glioma patients. In summary, these findings indicate that AMACR expression is increased in a glioblastoma cell line and glioma patients, suggesting that AMACR might be a potential diagnostic marker and therapeutic target for cancer, including glioma.

Isoliquiritigenin ameliorates caerulein-induced chronic pancreatitis by inhibiting the activation of PSCs and pancreatic infiltration of macrophages

Chronic pancreatitis (CP) is characterized by persistent inflammation of the pancreas that results in progressive loss of the endocrine and exocrine compartment owing to atrophy and/or replacement with fibrotic tissue. Currently, the clinical therapeutic scheme of CP is mainly symptomatic treatment including pancreatic enzyme replacement, glycaemic control and nutritional support therapy, lacking of specific therapeutic drugs for prevention and suppression of inflammation and fibrosis aggravating in CP. Here, we investigated the effect of isoliquiritigenin (ILG), a chalcone‐type dietary compound derived from licorice, on pancreatic fibrosis and inflammation in a model of caerulein‐induced murine CP, and the results indicated that ILG notably alleviated pancreatic fibrosis and infiltration of macrophages. Further in vitro studies in human pancreatic stellate cells (hPSCs) showed that ILG exerted significant inhibition on the proliferation and activation of hPSCs, which may be due to negative regulation of the ERK1/2 and JNK1/2 activities. Moreover, ILG significantly restrained the M1 polarization of macrophages (RAW 264.7) via attenuation of the NF‐κB signalling pathway, whereas the M2 polarization was hardly affected. These findings indicated that ILG might be a potential anti‐inflammatory and anti‐fibrotic therapeutic agent for CP.

Aldose Reductase Inhibitors of Plant Origin in the Prevention and Treatment of Alcoholic Liver Disease: A Minireview

Alcoholic liver disease (ALD) is caused by heavy alcohol consumption over a long period. Acetaldehyde-mediated toxicity, oxidative stress, and imbalance of lipid metabolism are generally considered involved in the initiation of ALD. There is an increasing requirement for alternative and natural medicine to treat ALD. Recently, aldose reductase (AR) has been reported to be involved in the development of ALD by affecting inflammatory cytokines, oxidative stress, and lipid metabolism. Here, we review the effect of plant-derived AR inhibitors on ALD in rodents. And we conclude that AR inhibitors of plant origin may enhance antioxidant capacity, inhibit lipid peroxidation and inflammatory cytokines expression, and activate AMP-activated protein kinase thereby subsequently suppressing alcohol-induced lipid synthesis in liver to achieve ALD protection. This review reveals that natural AR inhibitor may be potential therapeutic agent for ALD.

Natural products in licorice for the therapy of liver diseases: Progress and future opportunities

Liver diseases related complications represent a significant source of morbidity and mortality worldwide, creating a substantial economic burden. Oxidative stress, excessive inflammation, and dysregulated energy metabolism significantly contributed to liver diseases. Therefore, discovery of novel therapeutic drugs for the treatment of liver diseases are urgently required. Licorice is one of the most commonly used herbal drugs in Traditional Chinese Medicine for the treatment of liver diseases and drug-induced liver injury (DILI). Various bioactive components have been isolated and identified from the licorice, including glycyrrhizin, glycyrrhetinic acid, liquiritigenin, Isoliquiritigenin, licochalcone A, and glycycoumarin. Emerging evidence suggested that these natural products relieved liver diseases and prevented DILI through multi-targeting therapeutic mechanisms, including anti-steatosis, anti-oxidative stress, anti-inflammation, immunoregulation, anti-fibrosis, anti-cancer, and drug-drug interactions. In the current review, we summarized the recent progress in the research of hepatoprotective and toxic effects of different licorice-derived bioactive ingredients and also highlighted the potency of these compounds as promising therapeutic options for the treatment of liver diseases and DILI. We also outlined the networks of underlying molecular signaling pathways. Further pharmacology and toxicology research will contribute to the development of natural products in licorice and their derivatives as medicines with alluring prospect in the clinical application.

The Beneficial Roles of SIRT1 in Drug-Induced Liver Injury

Drug-induced liver injury (DILI) is a major cause of acute liver failure (ALF) as a result of accumulated drugs in the human body metabolized into toxic agents and helps generate heavy oxidative stress, inflammation, and apoptosis, which induces necrosis in hepatocytes and ultimately damages the liver. Sirtuin 1 (SIRT1) is said to have multiple vital roles in cell proliferation, aging, and antistress systems of the human body. The levels of SIRT1 and its activation precisely modulate its critical role in the interaction between multiple step procedures of DILI. The nuclear factor kappa-light-chain-enhancer of activated B cell- (NF-κB-) mediated inflammation signaling pathway, reactive oxygen species (ROS), DNA damage, mitochondrial membrane potential collapse, and endoplasmic reticulum (ER) stress also contribute to aggravate DILI. Apoptosis is regarded as the terminal reaction followed by multiple signaling cascades including caspases, p53, and mitochondrial dysfunction which have been said to contribute in DILI. The SIRT1 activator is regarded as a potential candidate for DILI, because the former could inhibit signaling of p53, NF-κB, and ER stress. On the other hand, overexpression of SIRT1 also enhances the activation of antioxidant responses via Kelch-like ECH-associated protein 1- (Keap1-) nuclear factor- (erythroid-derived 2-) like 2 (Nrf2) signaling. The current manuscript will highlight the mechanism of DILI and the interaction of SIRT1 with various cytoplasmic factors leading to DILI along with the summary of potent SIRT1 agonists.

Streptococcus gordonii induces bone resorption by increasing osteoclast differentiation and reducing osteoblast differentiation

Streptococcus gordonii is commonly found in the periapical endodontic lesions of patients with apical periodontitis, a condition characterized by inflammation and periapical bone loss. Since bone metabolism is controlled by osteoclastic bone resorption and osteoblastic bone formation, we investigated the effects of S. gordonii on the differentiation and function of osteoclasts and osteoblasts. For the determination of bone resorption activity in vivo, collagen sheets soaked with heat-killed S. gordonii were implanted on mouse calvaria, and the calvarial bones were scanned by micro-computed tomography. Mouse bone marrow-derived macrophages (BMMs) were stimulated with M-CSF and RANKL for 2 days and then differentiated into osteoclasts in the presence or absence of heat-killed S. gordonii. Tartrate-resistant acid phosphatase staining was performed to determine osteoclast differentiation. Primary osteoblast precursors were differentiated into osteoblasts with ascorbic acid and β-glycerophosphate in the presence or absence of heat-killed S. gordonii. Alkaline phosphatase staining and alizarin red S staining were conducted to determine osteoblast differentiation. Western blotting was performed to examine the expression of transcription factors including c-Fos, NFATc1, and Runx2. Heat-killed S. gordonii induced bone destruction in a mouse calvarial implantation model. The differentiation of RANKL-primed BMMs into osteoclasts was enhanced in the presence of heat-killed S. gordonii. Heat-killed S. gordonii increased the expression of c-Fos and NFATc1, which are essential transcription factors for osteoclast differentiation. On the other hand, heat-killed S. gordonii inhibited osteoblast differentiation and reduced the expression of Runx2, an essential transcription factor for osteoblast differentiation. S. gordonii exerts bone resorptive activity by increasing osteoclast differentiation and reducing osteoblast differentiation, which may be involved in periapical bone resorption.

SIRT1 activation by butein attenuates sepsis-induced brain injury in mice subjected to cecal ligation and puncture via alleviating inflammatory and oxidative stress

Sepsis-induced brain injury is frequently encountered in critically ill patients with severe systemic infection. Butein (3,4,2',4'-tetrahydroxychalcone) has been demonstrated as the neuro-protective agent via reducing inflammation and oxidative stress on neurons. Moreover, activation of silent information regulator 1 (SIRT1) inhibits apoptosis, oxidation and inflammation thus alleviating sepsis-induced multiorgan injuries. In present study, we show that butein administrated intraperitoneally (10 mg/kg) saved mice from sepsis-induced lethality by increasing 7-day survival rate after cecal ligation and puncture (CLP) surgery. Additionally, butein treatment enhanced SIRT1 signaling thus decreasing the Ac-NF-κB, Ac-FOXO1 and Ac-p53 levels, thus attenuating the brain injury of mice after CLP surgery by decreasing cerebral edema, maintaining the blood-brain barrier integrity, inhibiting neuronal apoptosis, and decreasing pro-inflammatory cytokines production (IL-6, TNF-α and IL-1β) and oxidative stress (downregulation of MDA, and upregulation of SOD and CAT) in both serum and cerebral cortex tissues. Moreover, butein treatment attenuated LPS induced neurological function loss. However, all above mentioned neuro-protective actions of butein were partially inhibited by EX527 co-treatment, one standard SIRT1 inhibitor. Collectively, butein attenuates sepsis-induced brain injury through alleviation of cerebral inflammation, oxidative stress and apoptosis by SIRT1 signaling activation.

Isoliquiritigenin Inhibits Cigarette Smoke-Induced COPD by Attenuating Inflammation and Oxidative Stress via the Regulation of the Nrf2 and NF-κB Signaling Pathways

Chronic obstructive pulmonary disease (COPD) is the major leading cause of disease with high-mortality worldwide. Cigarette smoke (CS) is a major factor for COPD. CS causes chronic inflammation and oxidative stress, which contributes to lung dysfunction in COPD. Isoliquiritigenin (ILG), a natural flavonoid derived from the root of liquorice, has been reported to possess antiinflammatory and antioxidant activity. In the present study, we tested the mechanism and protective effects of ILG on CS-induced COPD. Mice were exposed to CS for 2 h twice a day for 4 weeks. ILG was given orally 1 h before CS exposure twice a day for 4 weeks. The bronchial alveolar lavage fluid was collected to test the levels of inflammatory cytokines and the number of inflammatory cells. The lung tissues were obtained to evaluate the pathological changes, lung edema, myeloperoxidase (MPO) activity, malondialdehyde (MDA) level, as well as the expression of the nuclear factor-erythroid 2 (Nrf2) and nuclear factor κB (NF-κB) signaling pathways. The results showed that ILG reduced the infiltration of inflammatory cells and the production of inflammatory cytokines. ILG also reversed CS-induced lung pathological injuries, wet/dry ratio, MPO activity, and MDA level. Further research also showed that ILG dose-dependently up-regulated the expression of Nrf2 and down-regulated the expression of NF-κB signaling pathways induced by CS. In conclusion, ILG protected against CS-induced COPD by inhibiting inflammatory and oxidative stress via the regulation of the Nrf2 and NF-κB signaling pathways.