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Background: Lung squamous cell carcinoma (LUSC) currently has limited therapeutic options because of the relatively few validated targets and the lack of clinical drugs for some of these targets. Although NRF2/NFE2L2 pathway activation commonly occurs in LUSC, NRF2 has predominantly been studied in other cancer models. Here, we investigated the function of NRF2 in LUSC, including in organoid models, and we explored the activity of a small molecule NRF2 inhibitor ML385, which has not previously been investigated in LUSC. Methods: We first explored the role of NRF2 signaling in LUSC cancer cell line and organoid proliferation through NRF2 knockdown or ML385 treatment, both in vivo and in vitro. Next, we performed Western blot and immunofluorescence assays to determine the effect of NRF2 inhibition on PI3K‐mTOR signaling. Finally, we used cell viability and clonogenic assays to explore whether ML385 could sensitize LUSC cancer cells to PI3K inhibitors. Results: We find that downregulation of NRF2 signaling inhibited proliferation of LUSC cancer cell lines and organoids, both in vivo and in vitro. We also demonstrate that inhibition of NRF2 reduces PI3K‐mTOR signaling, with two potential mechanisms being involved. Although NRF2 promotes AKT phosphorylation, it also acts downstream of AKT to increase RagD protein expression and recruitment of mTOR to lysosomes after amino acid stimulation. We also find that ML385 potentiates LUSC growth inhibition by a pan‐PI3K inhibitor, which correlates with stronger inhibition of PI3K‐mTOR signaling. Conclusions: Our data provide additional support for NRF2 promoting LUSC growth through PI3K‐mTOR activation and support development of NRF2 inhibitors for the treatment of LUSC. [ABSTRACT FROM AUTHOR]

As one of the major diabetic microvascular complications, diabetic retinopathy (DR) is mainly initiated by the blood‐retinal barrier (BRB) dysfunction. Chlorogenic acid (CGA) is a natural polyphenolic compound in Lonicerae Japonicae Flos, which traditionally has the beneficial function for eyes and is commonly included in many anti‐diabetic formulas. In this study, the potential protective mechanism of CGA against DR was investigated. Streptozotocin (STZ) was used to induce diabetes in mice. CGA attenuated BRB dysfunction and reversed endothelial‐mesenchymal transition (EndoMT) and epithelial‐mesenchymal transition (EMT) in retinas in vivo. CGA inhibited microglia activation and reduced tumor necrosis factor (TNF)α release both in vivo and in vitro. CGA promoted nuclear factor erythroid 2‐related factor 2 (Nrf2) activation and prevented EndoMT/EMT in TNFα‐treated human retinal endothelial cells (HRECs) or retinal pigment epithelial APRE19 cells. CGA alleviated endothelial/epithelial barrier oxidative injury in HRECs or APRE19 cells stimulated with TNFα, but this effect was disappeared in cells co‐incubated with Nrf2 inhibitor. Additionally, the CGA‐supplied alleviation on BRB damage and EndoMT/EMT was markedly weakened in retinas from STZ‐treated Nrf2 knock‐out mice. All results suggest that CGA improves DR through attenuating BRB injury by reducing microglia‐initiated inflammation and preventing TNFα‐induced EndoMT/EMT and oxidative injury via inducing Nrf2 activation. [ABSTRACT FROM AUTHOR]

Hepatic sinusoidal obstruction syndrome (HSOS) causes considerable morbidity and mortality in clinic. Up to now, the molecular mechanisms involved in the development of HSOS still remain unclear. Here, we report that hepatic inflammation initiated by damage-associated molecular patterns (DAMPs) plays a critical role in the development of HSOS. Monocrotaline (MCT) belongs to pyrrolizidine alkaloids. Monocrotaline-induced HSOS in mice and rats was evidenced by the increased serum alanine/aspartate aminotransferase (ALT/AST) activities, the elevated hepatic metalloproteinase 9 (MMP9) expression, and results from liver histological evaluation and scanning electron microscope observation. However, MCT-induced HSOS was markedly attenuated in myeloid differentiation primary response gene 88 (MyD88), TIR-domain-containing adapter-inducing interferon-β (TRIF) and toll like receptor 4 (TLR4) knock-out mice. Monocrotaline increased liver myeloperoxidase activity, serum contents of proinflammatory cytokines, hepatic aggregation of immune cells, and nuclear accumulation of nuclear factor κB (NFκB). However, these inflammatory responses induced by MCT were all diminished in MyD88, TRIF, and TLR4 knock-out mice. Monocrotaline elevated serum contents of DAMPs including high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) both in mice and in rats. HSOS was markedly exacerbated and serum contents of HMGB1 and HSP60 were elevated in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice treated with MCT. Our findings indicate that hepatic inflammatory injury mediated by DAMPs-initiated TLR4-MyD88/TRIF-NFκB inflammatory signal pathway plays an important role in HSOS development. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a worldwide clinical issue that generally causes hepatic cirrhosis. Lonicerae Japonicae Flos (dried flower buds of Lonicera japonica Thunb) is a traditional heat-clearing and detoxifying herbal medicine in China. This study aims to observe the protection of the water extract of Lonicerae Japonicae Flos (FL) from carbon tetrachloride (CCl4)-induced liver fibrosis in mice. Liver fibrosis was induced in mice by intraperitoneal injection of 2 ml/kg CCl4 twice a week for 4 weeks. FL's attenuation of CCl4-induced liver fibrosis in mice was evidenced by the results of Masson's trichrome and Sirius red staining, liver hydroxyproline content and serum amount of collagen IV. FL reduced hepatic stellate cells (HSCs) activation and reversed the epithelial-mesenchymal transition (EMT) process in mice treated with CCl4. FL also alleviated liver oxidative stress injury and enhanced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) anti-oxidant signaling pathway in mice treated with CCl4. Additionally, the main phenolic acids in FL including chlorogenic acid (CGA) and caffeic acid (CA) both reduced HSCs activation in vitro. In summary, FL attenuates CCl4-induced liver fibrosis in mice by inhibiting HSCs activation, reversing EMT and reducing liver oxidative stress injury via inducing Nrf2 activation. CGA may be the main active compound contributing to the antifibrotic activity of FL. [ABSTRACT FROM AUTHOR]

Hepatic sinusoidal obstruction syndrome (HSOS) is a rare and life-threatening liver disease. (+)-Catechin is a natural dietary flavonol with high antioxidant capacity. This study aims to investigate the involvement of nuclear factor erythroid 2-related factor 2 (Nrf2) antioxidant signalling pathway in the protection of (+)-catechin hydrate (CAT) against monocrotaline (MCT)-induced HSOS. Results of serum alanine/aspartate aminotransferases (ALT/AST) activities, total bilirubin (TBil) and bile acids (TBA) amounts, liver histological observation, scanning electron microscope evaluation, and hepatic metalloproteinase-9 (MMP-9) expression all demonstrated the protection of CAT against MCT-induced HSOS in rats. CAT attenuated MCT-induced liver oxidative injury in rats and the formation of cellular reactive oxygen species (ROS) in human hepatic sinusoidal endothelial cells (HHSECs). CAT-enhanced Nrf2 nuclear translocation in livers from MCT-treated rats and in HHSECs treated with MCT, and further increased the expression of Nrf2-dependent genes including catalytic or modify subunit of glutamate-cysteine ligase (GCLC/GCLM), haem oxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO1). Moreover, GCL inhibitor L-buthionine-(S, R)-sulfoximine (BSO), NQO1 inhibitor diminutol (Dim), and HO-1 inhibitor zinc protoporphyrin (ZnPP) all abrogated CAT-provided the protection against MCT-induced cytotoxicity in HHSECs. The results of molecular docking analysis indicated the potential interaction of CAT with the Nrf2-binding site in kelch-like ECH-associated protein-1 (Keap1) protein. In summary, this study demonstrated the critical involvement of Nrf2 antioxidant signalling pathway in CAT-provided the protection against MCT-induced HSOS. [ABSTRACT FROM AUTHOR]

Hepatotoxicity due to acetaminophen (APAP) overdose is a leading cause of drug-induced acute liver failure in clinic. Chlorogenic acid (CGA), a dietary polyphenol, was reported to prevent APAP-induced liver injury in our previous studies. This study aims to investigate the protection provided by CGA against APAP-induced hepatotoxicity via focusing on nuclear factor erythroid 2-related factor 2 (Nrf2) and extracellular regulated protein kinases (ERK)1/2. CGA prevented APAP-induced oxidative liver injury and enhanced Nrf2 activation in mice and in hepatocytes in vitro. CGA-provided the protection against APAP-induced hepatotoxicity was diminished after the application of Nrf2 siRNA in vitro and Nrf2 knockout mice in vivo. CGA enhanced the expression of heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1), and their inhibitors reduced the protection provided by CGA against APAP-induced cytotoxicity in hepatocytes. Molecular docking results indicated the potential interaction of CGA with Nrf2 binding site in Kelch-like ECH-associating protein-1 (Keap1). CGA decreased the expression of protein phosphatases including PP2A subunit A (PP2A-A) and PP5, and induced the sustained ERK1/2 phosphorylation. Moreover, ERK1/2 inhibitors (U0126 and PD98059) and ERK2 siRNA abrogated CGAinduced Nrf2 phosphorylation and its subsequent transcriptional activation, and also reduced the protection provided by CGA against APAP-induced cytotoxicity in hepatocytes. These results suggest that CGA protects against APAP-induced hepatotoxicity by activating Nrf2 antioxidative signaling pathway via blocking the binding of Nrf2 to its inhibitor protein Keap1, and ERK1/2 plays a critical role in regulating CGA-induced Nrf2 transcriptional activation. CGA is a promising therapeutic agent for the detoxification of APAP-induced hepatotoxicity. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is one of the major complications in diabetes patients. Reactive oxygen species (ROS) play key roles in DN progression. As a primary transcription factor, Nrf2 controls the antioxidant response to maintain cellular redox homeostasis. Herein we systemically examined the role of Nrf2 in DN progression and its regulatory mechanism in a mouse model bearing type II diabetes and in cultured human renal mesangial cells (HRMCs). We found that Nrf2 could ameliorate DN progression by transcriptional repression of TGFβ1 in vivo and in vitro . Moreover, Nrf2 bound to the specific region in TGFβ1 promoter by interactions with transcription factors c-Jun and SP1. Significant abolishment of Nrf2-mediated TGFβ1 transcriptional repression could be accomplished by knockdown of either c - Jun or SP1 , and site-directed mutagenesis of c-Jun and SP1 binding sites in the TGFβ1 promoter specific region. Moreover, after interacting with c-Jun and SP1, Nrf2 inhibited c-Jun and SP1 activations, and thus reversed c-Jun- and SP1-promoted TGFβ1 transcription. In all, Nrf2 could slow down DN progression by repression of TGFβ1 in a c-Jun and SP1-dependent way. Our findings may provide novel clues for DN preventions and interventions in clinic. [ABSTRACT FROM AUTHOR]

Metabolic-associated steatotic liver disease (MASLD), known as non-alcoholic fatty liver disease (NAFLD) in the past, encompasses a range of liver pathological conditions marked by the excessive lipid accumulation. Consumption of coffee is closely associated with the reduced risk of MASLD. Caffeic acid (CA), a key active ingredient in coffee, exhibits notable hepatoprotective properties. This study aims to investigate the improvement of CA on MASLD and the engaged mechanism. Mice underwent a 12-week high-fat diet (HFD) regimen to induce MASLD, and liver pathology was assessed using hematoxylin-eosin (H&E) and oil red O (ORO) staining. Hepatic inflammation was evaluated by F4/80 and Ly6G immunohistochemistry (IHC) and myeloperoxidase (MPO) measurement. Pathways and transcription factors relevant to MASLD were analyzed by using microarray data from patients' livers. Oxidative damage was evaluated by detecting reactive oxygen species (ROS), malondialdehyde (MDA), glutathione (GSH) and superoxide dismutase (SOD). Co-immunoprecipitation (CoIP), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) were used to validate the binding between CA and its target protein. CA significantly alleviated liver damage, steatosis and inflammatory injury, and reduced the elevated NAFLD activity score (NAS) in HFD-fed mice. Clinical data indicate that fatty acid metabolism and ROS generation are pivotal in MASLD progression. CA increased the expression of fibroblast growth factor 21 (FGF21), FGF receptor 1 (FGFR1) and β -Klotho (KLB), and promoted fatty acid consumption. Additionally, CA mitigated oxidative stress injury and activated nuclear factor erythroid 2-related factor-2 (Nrf2). In primary hepatocytes isolated from Nrf2 knockout mice, CA's promotion on FGF21 release and inhibition on oxidative stress and lipotoxicity was disappeared. CA could directly bind to kelch-like ECH-associated protein 1 (Keap1) that is an Nrf2 inhibitor protein. This study suggests that CA alleviates MASLD by reducing hepatic lipid accumulation, lipotoxicity and oxidative damage through activating Nrf2 via binding to Keap1. [Display omitted] • CA alleviated MASLD. • CA improved hepatocyte oxidative injury during MASLD by activating Nrf2. • CA up-regulated FGF21 expression. • CA reduced liver steatosis during MASLD via Nrf2-mediated FGF21 expression. • CA induced Nrf2 activation by directly binding to Keap1. [ABSTRACT FROM AUTHOR]

Liver fibrosis is a key and reversible stage in the progression of many chronic liver diseases to cirrhosis or hepatocellular carcinoma. Forsythiaside-A (FTA), a main compound isolated from Forsythiae Fructus, has an excellent liver protective activity. This study aims to investigate the efficacy of FTA in improving cholestatic liver fibrosis. Bile-duct-ligation (BDL) was conducted to induce liver fibrosis in mice. Hepatic collagen deposition was evaluated by Masson and Sirus red staining. The bile acid spectrum in the liver and serum was analyzed by mass spectrometry. Liver oxidative stress injury and mitochondria damage were observed by using Mito-Tracker Red fluorescence staining, transmission electron microscopy, etc. The level of ferrous iron (Fe2+) and the expression of ferroptosis-associated molecules were detected. The binding between FTA and its target protein was confirmed by Co-immunoprecipitation (Co-IP), cellular thermal shift assay (CETSA), drug affinity responsive target stability (DARTS) and surface plasmon resonance (SPR). Our results demonstrated that FTA alleviated BDL-induced liver fibrosis in mice. FTA did not decrease the elevated amount of bile acids in BDL-treated mice, but reduced the bile acid-induced mitochondrial damage, oxidative stress and ferroptosis in hepatocytes, and also induced nuclear factor erythroid 2-related factor-2 (Nrf2) activation. In Nrf2 knock-out mice, the FTA-provided protection against BDL-induced liver fibrosis was disappeared, and FTA's inhibition on mitochondrial damage, oxidative stress and ferroptosis were lowered. Further results displayed that FTA could directly bind to Kelch-like ECH-associated protein-1 (Keap1), thereby activating Nrf2. Moreover, the BDL-induced liver fibrosis was markedly weakened in liver-specific Keap1 knockout mice. Hence, this study suggests that FTA alleviated the BDL-induced liver fibrosis through attenuating mitochondrial damage and ferroptosis in hepatocytes by activating Nrf2 via directly binding to Keap1. [Display omitted] • FTA improved BDL-induced liver fibrosis in mice. • FTA attenuated ferroptosis induced by TCA and TCDCA in hepatocytes. • Nrf2 was critical for FTA's efficacy in reducing ferroptosis. • Nrf2 was critical for FTA's efficacy in improving liver fibrosis. • FTA induced Nrf2 nuclear translocation by directly binding to Keap1. [ABSTRACT FROM AUTHOR]

Liver regeneration has become a new hotspot in the study of drug-induced liver injury (DILI). Baicalin has already been reported to alleviate acetaminophen (APAP)-induced acute liver injury in our previous study. This study aims to observe whether baicalin also promotes liver regeneration after APAP-induced liver injury and to elucidate its engaged mechanism. Baicalin alleviated APAP-induced hepatic parenchymal cells injury and enhanced the number of mitotic and proliferating cell nuclear antigen (PCNA)-positive hepatocytes in APAP-intoxicated mice. Baicalin increased hepatic PCNA and cyclinD1 expression in APAP-intoxicated mice. Baicalin induced the activation of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome, leading to the increased hepatic expression of interleukin-18 (IL-18) and IL-1β in APAP-intoxicated mice. The results in vitro demonstrated that IL-18 promoted the proliferation of human normal liver L-02 cells. Moreover, the baicalin-provided promotion on liver regeneration in APAP-intoxicated mice was diminished after the application of NLRP3 inhibitor MCC950 and the recombinant mouse IL-18 binding protein (rmIL-18BP). Baicalin induced the cytosolic accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2), and increased the interaction between Nrf2 with Nlrp3, ASC and pro-caspase-1 in livers from APAP-intoxicated mice. Furthermore, the baicalin-provided NLRP3 inflammasome activation and promotion on liver regeneration after APAP-induced liver injury in wild-type mice were diminished in Nrf2 knockout mice. In conclusion, baicalin promoted liver regeneration after APAP-induced acute liver injury in mice via inducing Nrf2 accumulation in cytoplasm that led to NLRP3 inflammasome activation, and then caused the increased expression of IL-18, which induced hepatocytes proliferation. Image 1 • Baicalin improved liver regeneration after APAP-induced acute liver injury in mice. • Baicalin induced NLRP3 inflammasome activation and the subsequent IL-18 produce. • IL-18 promoted the proliferation of hepatocytes. • IL-18 was critical for the baicalin-provided promotion on liver regeneration after APAP-induced liver injury. • Baicalin increased NLRP3 inflammasome assembly by inducing Nrf2 accumulation in cytoplasm. [ABSTRACT FROM AUTHOR]

Hyperglycemia-induced blood-retinal barrier (BRB) breakdown is an early and typical event of diabetic retinopathy (DR). Although chronic inflammation plays an important role in DR development, the concrete mechanism remains unclear. This study aims to investigate the role of microglia cells-triggered inflammatory response in hyperglycemia-induced BRB breakdown and the amelioration of galangin, a natural flavonoid. Galangin alleviated BRB breakdown in streptozotocin-induced diabetic mice. D-glucose (25 mM)-stimulated microglia BV2 cells induced BRB damage in vitro, but galangin reversed this injury. Galangin decreased the activation of microglia cells, ROS formation, the phosphorylation of extracellular-signal-regulated protein kinase (ERK)1/2, the transcriptional activation of nuclear factor κB (NFκB) and early growth response (Egr1) protein, and the elevated expression of tumor necrosis factor (TNF)-α both in vitro and in vivo. ERK1/2 inhibitor U0126 reduced ROS formation, the activation of NFκB and Egr1, and the elevated TNFα expression in D-glucose-stimulated BV2 cells. N-acetylcysteine, a well-known antioxidant, abrogated D-glucose-induced NFκB and Egr1 activation in BV2 cells. Galangin also reversed the decreased expression of claudin1 and occludin, and the increased BRB injury and ROS formation in TNFα-treated human retinal endothelial cells (HRECs) and ARPE19 cells. Galangin induced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in both HRECs and ARPE19 cells. Moreover, the galangin-provided attenuation on BRB breakdown was diminished in Nrf2 knockout diabetic mice. In conclusion, galangin alleviated DR by attenuating BRB damage via inhibiting microglia-triggered inflammation and further reversing TNFα-induced BRB dysfunction by abrogating oxidative stress injury via activating Nrf2. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The breakdown of blood-retinal barrier (BRB) is an early and typical event during the development of diabetic retinopathy (DR). Scutellarin (SC) is a natural flavonoid. This study aims to investigate the protection of SC from BRB damage via focusing on inhibiting microglia-initiated inflammation and subsequent oxidative stress injury. SC attenuated BRB breakdown and the reduced expression of claudin-1 and claudin-19 in STZ-induced diabetic mice. SC reduced microglia cells activation both in vivo and in vitro. The results of transendothelial/transepithelial electrical resistance (TEER/TER) and fluorescein isothiocyanate (FITC)-conjugated dextran cell permeability assay showed that SC attenuated BRB damage induced by d -glucose (25 mM)-stimulated microglia BV2 cells. SC suppressed nuclear factor κB (NFκB) activation and tumor necrosis factor (TNF)-α expression induced by d -glucose (25 mM) in BV2 cells. SC decreased the phosphorylation of extracellular regulated protein kinase (ERK)1/2 both in vivo and in vitro. MEK1/2 inhibitor U0126 reduced the d -glucose-induced NFκB nuclear accumulation and TNFα expression in BV2 cells. Next, SC improved the decreased expression of claudin-1 and claudin-19, the increased BRB damage and cellular reactive oxygen species (ROS) formation, and enhanced nuclear accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2) in TNFα-treated human retinal endothelial cells (HRECs) and APRE19 cells. Moreover, the SC-provided alleviation on BRB breakdown in STZ-induced diabetic mice was diminished in Nrf2 knock-out mice. In conclusion, SC alleviates BRB breakdown via abrogating retinal inflammatory responses and subsequent oxidative stress injury initiated by microglia cells that is activated by hyperglycemia during DR development. [ABSTRACT FROM AUTHOR]

Hepatic sinusoidal obstruction syndrome (HSOS) is a serious and life-threatening liver disease. Liquiritigenin (LG) and liquiritin (LQ) are natural flavonoids distributed in Glycyrrhizae Radix et Rhizoma (Gan-cao). This study aims to investigate the protective effect and mechanism of LG and LQ against monocrotaline (MCT)-induced HSOS. Results of serum alanine/aspartate aminotransferases (ALT/AST) activities, liver histological evaluation and scanning electron microscope observation, and hepatic metalloproteinase-9 (MMP-9) expression demonstrated that LG and LQ both alleviated HSOS induced by MCT in rats. Results of hepatic reactive oxygen species (ROS), malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), oxidized glutathione (GSSG) and reduced glutathione (GSH) contents, glutathione reductase (GR) and superoxide dismutase (SOD) activities showed that LG and LQ attenuated MCT-induced liver oxidative stress injury. Furthermore, LG and LQ were found to promote Nrf2 nuclear translocation and lead to the increased expression of Nrf2 downstream antioxidative genes. Molecule docking analysis indicated the potential interaction of LG and LQ with Nrf2 binding site in the kelch-like ECH-associated protein-1 (Keap1) protein. Finally, Nrf2 knock-out mice were used. The results showed that LG and LQ both alleviated MCT-induced HSOS in wild-type mice, but such protection was totally diminished in Nrf2 knock-out mice. In conclusion, our study revealed that LG and LQ alleviated MCT-induced HSOS by inducing the activation of hepatic Nrf2 antioxidative defense system. [ABSTRACT FROM AUTHOR]

Acetaminophen (APAP)-induced hepatotoxicity is the main cause of drug-induced liver injury. This study investigated the protection of baicalin and its aglycone baicalein against APAP-induced hepatotoxicity and its mechanism. Baicalein and baicalin alleviated APAP-induced hepatotoxicity both in vitro and in vivo . Moreover, this baicalin-provided protection was not diminished in hepatocytes or mice treated with β-glucuronidase inhibitor. Results of liver glutathione (GSH) and reactive oxygen species (ROS) formation demonstrated the alleviation of baicalein and baicalin on APAP-induced liver oxidative stress injury. Baicalein and baicalin induced the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) and increased the expression of its downstream antioxidant genes. Baicalein and baicalin-provided protection was diminished after the application of Nrf2 siRNA in hepatocytes and Nrf2 knock-out mice. Molecular docking results indicate the potential interaction of baicalein and baicalin with kelch-like ECH-associated protein-1 (Keap1). Baicalein and baicalin induced the sustained phosphorylation of extracellular regulated protein kinases (ERK)1/2 and protein kinase C (PKC). Moreover, ERK1/2 and PKC inhibitors both abrogated Nrf2 phosphorylation and its subsequent activation, and the protection against APAP-induced hepatotoxicity induced by baicalein and baicalin. In summary, baicalein and baicalin alleviate APAP-induced hepatotoxicity by activating Nrf2 via blocking the binding of Nrf2 with Keap1 and inducing Nrf2 phosphorylation. ERK1/2 and PKC are both critical for regulating the phosphorylation of Nrf2 induced by baicalein or baicalin. [ABSTRACT FROM AUTHOR]

As a well-known analgesic drug, acetaminophen (APAP) is commonly used to relieve pain for patients with chronic painful diseases. Our previous study has shown that long-term ingestion of APAP caused liver fibrosis in mice. This study further investigated the critical role of nuclear factor erythroid 2-related factor 2 (Nrf2) in regulating APAP-induced liver fibrosis in mice and the anti-fibrotic effect of natural compound andrographolide (Andro). Our results showed that hepatic collagen deposition and hepatic stellate cells (HSCs) activation induced by APAP were more serious in Nrf2 knock-out mice than in normal wild-type mice. Andro reduced HSCs activation in vitro , and also decreased hepatic collagen deposition and HSCs activation induced by APAP in mice. Andro alleviated liver oxidative stress injury induced by APAP in mice and reduced cellular formation of reactive oxygen species (ROS) in HSCs. Andro enhanced Nrf2 nuclear translocation and increased the expression of Nrf2 downstream antioxidant genes both in vitro and in vivo . Furthermore, the Andro-provided protection against APAP-induced liver fibrosis was diminished in Nrf2 knock-out mice. In summary, Nrf2 is critically involved in preventing liver fibrosis induced by long-term administration of APAP in mice, and Andro alleviates APAP-induced liver fibrosis by attenuating liver oxidative stress injury via inducing Nrf2 activation. This study points out the potential application of Andro in the treatment of liver fibrosis in clinic. [ABSTRACT FROM AUTHOR]

Non-alcoholic fatty liver disease (NAFLD) is emerging as the most common chronic liver disease and is closely associated with metabolic syndrome. Endothelial dysfunction was involved in many metabolic diseases, but the concrete participation of hepatic vascular endothelial dysfunction in liver steatosis that is an early stage of NAFLD is still unclear. In this study, the formation of liver steatosis and the elevation of serum insulin content were observed accompanying with the decreased vascular endothelial cadherin (VE-cadherin) expression in hepatic vessels from db/db mice, Goto-Kakizaki (GK) and high-fat diet (HFD)-fed rats. Liver steatosis was obviously enhanced in mice after the application of VE-cadherin neutralizing antibody. In vitro results showed that insulin decreased VE-cadherin expression and caused endothelial barrier breakdown. Furthermore, the alteration of VE-cadherin expression was found to be positively related with the transcriptional activation of nuclear erythroid 2-related factor 2 (Nrf2), and chromatin immunoprecipitation (ChIP) assay displayed that Nrf2 could directly regulate VE-cadherin expression. Insulin reduced Nrf2 activation by decreasing sequestosome-1 (p62/SQSTM1) expression downstream of insulin receptor. Moreover, the p300-mediated Nrf2 acetylation was weakened by enhancing the competitive binding of transcription factor GATA-binding protein 4 (GATA4) to p300. Finally, we found that erianin, a natural compound, could promote VE-cadherin expression by inducing Nrf2 activation, thereby alleviating liver steatosis in GK rats. Our results suggest that hepatic vascular endothelial dysfunction owing to the VE-cadherin deficiency dependent on the reduced Nrf2 activation promoted liver steatosis, and erianin alleviated liver steatosis through enhancing Nrf2-mediated VE-cadherin expression. [Display omitted] • Liver steatosis was associated with the decreased VE-cadherin expression. • Nrf2 directly regulated the expression of VE-cadherin in hepatic vessels. • Insulin decreased VE-cadherin expression via downregulating Nrf2 activation. • Nrf2 activation was inhibited by the enhanced p300-mediated GATA4 acetylation. • Erianin reduced liver steatosis by enhancing Nrf2-mediated VE-cadherin expression. [ABSTRACT FROM AUTHOR]

Hepatic sinusoidal obstruction syndrome (SOS) is a rare liver disease with considerable mortality. This study is designed to observe the protection of quercetin and baicalein against monocrotaline (MCT)-induced SOS in rats and its engaged mechanism. Rats were pre-administrated with MCT (90 mg/kg) to induce SOS, and 6, 30 h later were orally given with quercetin and baicalein (40 mg/kg) twice. Results of detecting rats with liver ascites, measuring serum transaminases, total bilirubin (TBil) and bile acids (TBA), analyzing blood cells, liver histological evaluation and scanning electron microscope observation all demonstrated the detoxification of quercetin and baicalein against MCT-induced SOS in rats. Quercetin and baicalein reduced the increased metalloproteinase-9 (MMP-9) expression, liver myeloperoxidase (MPO) activity, toll-like receptor (TLR)-2,3,6,9 expression and nuclear factor κB (NFκB) transcriptional activation induced by MCT. Quercetin and baicalein reduced MCT-induced nuclear translocation of early growth response1 (Egr1) and increased expression of Serpine1 and tissue factor (TF). Quercetin and baicalein reduced MCT-induced increased liver malondialdehyde (MDA) amount and enhanced the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). Quercetin and baicalein also abrogated MCT-induced activation of mitogen-activated protein kinases (MAPKs) and phosphatidylinositol 3-kinase (PI3K) signaling cascades. In conclusion, this study demonstrated the protection of quercetin and baicalein against MCT-induced SOS in rats, indicating the potential application of them for the treatment of SOS in clinic. Transcriptional factor NFκB, Egr1 and Nrf2-regulated inflammation, coagulation-fibrinolysis and antioxidant, and PI3K and MAPKs signaling cascades are all involved such protection. [ABSTRACT FROM AUTHOR]

Hepatic sinusoidal obstruction syndrome (SOS) is a highly lethal liver disease. This study aims to observe the protection and its engaged mechanism of chlorogenic acid (CGA) against monocrotaline (MCT)-induced SOS. Results of detecting liver ascites, measuring serum transaminases, liver histological evaluation and scanning electron microscope observation all demonstrated that CGA prevented MCT-induced SOS in rats. CGA reduced MCT-induced increased liver myeloperoxidase (MPO) activity, tumor necrosis factor (TNF)α and interleukin (IL)-1β mRNA expression, toll-like receptor (TLR)-2,3,6,9 expression, and nuclear factor κB (NFκB) transcriptional activation. CGA also decreased MCT-induced early growth response1 (Egr1) activation. CGA reduced MCT-induced elevated liver malondialdehyde (MDA) amount and enhanced nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2). CGA blocked MCT-induced PI3K and MAPKs activation. In conclusion, this study demonstrates the protection of CGA against MCT-induced SOS. Transcriptional factor NFκB, Egr1 and Nrf2-regulated inflammation, coagulation-fibrinolysis, and antioxidant, and PI3K and MAPKs all contribute to such protection. [ABSTRACT FROM AUTHOR]

Acute liver failure induced by acetaminophen (APAP) overdose is the main cause of drug-induced liver injury (DILI). Caffeic acid (CA) is a phenolic compound from many natural products. This study aims to investigate the protective mechanism of CA in APAP-induced liver injury. The results of serum alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO) activity, liver glutathione (GSH) and reactive oxygen species (ROS) levels demonstrated the protection of CA against APAP-induced liver injury. Liver histological observation provided further evidences of CA-induced protection. CA was found to reverse the APAP-induced decreased cell viability in human normal liver L-02 cells and HepG2 cells. CA also reduced the increased cellular ROS level induced by APAP in hepatocytes. The results of luciferase assay and Western-blot analysis showed that CA increased the transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence of APAP. Nrf2 siRNA reduced the protection of CA against APAP-induced hepatotoxicity. CA also reversed the APAP-induced decreased mRNA and protein expression of heme oxygenase 1 (HO-1) and NAD(P)H: quinone oxidoreductase 1(NQO1). In addition, HO-1 inhibitor zinc protoporphyrin (ZnPP) and NQO1 inhibitor diminutol (Dim) reduced the protection of CA against APAP-induced hepatotoxicity. CA also decreased the expression of kelch-like ECH-associated protein-1(Keap1). Molecular docking indicated the potential interacting of CA with Nrf2 binding site in the Keap1 protein. CA had little effect on the enzymatic activity of cytochrome P450 (CYP) 3A4 and CYP2E1 in vitro . In conclusion, we demonstrated that CA prevented APAP-induced hepatotoxicity by decreasing Keap1 expression, inhibiting binding of Keap1 to Nrf2, and thus activating Nrf2 and leading to increased expression of antioxidative signals including HO-1 and NQO1. [ABSTRACT FROM AUTHOR]

Acetaminophen (APAP)-induced acute liver failure is a serious clinic issue. Our previous study showed that chlorogenic acid (CGA) alleviated APAP-induced liver inflammatory injury, but its concrete mechanism is still not clear. This study aims to elucidate the engaged mechanism involved in the CGA-provided alleviation on APAP-induced liver inflammation. CGA reduced the increased hepatic infiltration of immune cells and the elevated serum contents of high mobility group box 1 (HMGB1) and heat shock protein 60 (HSP60) in mice treated with APAP. CGA decreased the enhanced hepatic mRNA expression of some pro-inflammatory molecules in mice treated with APAP and in RAW264.7 cells stimulated with HMGB1 or HSP60. CGA attenuated liver mitochondrial injury, rescued the decreased lon protease homolog (Lon) protein expression, and reduced mitochondrial HSP60 release in mice treated with APAP. Moreover, the CGA-provided alleviation on APAP-induced liver inflammatory injury was diminished in mice treated with anti-HSP60 antibody. Further results showed that the CGA-provided alleviation on APAP-induced liver inflammation was also diminished in nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice. Meanwhile, the CGA-provided reduce on serum HSP60 content and restore of mitochondrial Lon protein expression were all diminished in Nrf2 knock-out mice treated with APAP. In conclusion, our study revealed that CGA alleviated APAP-induced liver inflammatory injury initiated by HSP60 or HMGB1, and Nrf2 was critical for regulating the mitochondrial HSP60 release via rescuing the reduced mitochondrial Lon protein expression. Image 1 [ABSTRACT FROM AUTHOR]