Chalcone Derivative L6H21 Reduces EtOH + LPS-Induced Liver Injury Through Inhibition of NLRP3 Inflammasome Activation.

BACKGROUND: Chronic alcohol intake increases circulating endotoxin levels causing excessive inflammation that aggravates the liver injury. (E)-2,3-dimethoxy-4'-methoxychalcone (L6H21), a derivative of chalcone, has been found to inhibit inflammation in cardiac diseases and nonalcoholic fatty liver disease. However, the use of L6H21 in alcoholic liver disease to inhibit exotoxin-associated inflammation has not been explored. In this study, we examined the effects of L6H21 on EtOH + LPS-induced hepatic inflammation, steatosis, and liver injury and investigated the underlying mechanisms. METHODS: C57BL6 mice were treated with 5% EtOH for 10 days, and LPS was given to the mice 6 hours before sacrificing. One group of mice was supplemented with L6H21 with EtOH and LPS. RAW264.7 cells were used to analyze the effects of L6H21 on macrophage activation. RESULTS: EtOH + LPS treatment significantly increased hepatic steatosis and serum levels of alanine transaminase (ALT) and aspartate transaminase (AST), which were reduced by L6H21 treatment. EtOH + LPS treatment increased hepatic inflammation, as shown by the increased hepatic protein levels of Toll-like receptor-4, p65, and p-IκB, and increased oxidative stress, as shown by protein carbonyl levels and reactive oxygen species formation, which were reduced by L6H21 treatment. In addition, L6H21 treatment markedly inhibited EtOH + LPS-elevated hepatic protein levels of NLRP3, cleaved caspase-1, cleaved IL-1ß, and caspase-1-associated apoptosis. CONCLUSIONS: Our results demonstrate that L6H21 treatment inhibits EtOH + LPS-induced liver steatosis and injury through suppression of NLRP3 inflammasome activation. L6H21 may be used as an alternative strategy for ALD prevention/treatment.

Apelin-13 Administration Protects Against LPS-Induced Acute Lung Injury by Inhibiting NF-κB Pathway and NLRP3 Inflammasome Activation.

BACKGROUND/AIMS: Acute lung injury (ALI) is induced by a variety of external and internal factors and leads to acute progressive respiratory failure. Previous studies have shown that apelin-13 can decrease the acute lung injury induced by LPS, but the specific mechanism is unclear. Therefore, a mouse lung injury model and a cell model were designed to explore the mechanism of how apelin-13 alleviates the acute lung injury caused by LPS. METHODS: The effect of apelin-13 on LPS-induced structural damage was determined by H&E staining and by the wet/dry weight ratio. The related inflammatory factors in BALF were examined by ELISA. The apoptotic pathway and the NF-κB and NLRP3 inflammasome pathways were evaluated by using Western blotting and immunofluorescence staining. RESULTS: LPS induced the structural damage and the production of inflammatory cytokines in the lung tissues of mice. These deleterious effects were attenuated by apelin-13 administration. The protective effects of apelin-13 were associated with decreased reactive oxygen species (ROS) formation and the inhibition of the activation of the NF-κB and NLRP3 inflammasome pathways in mice and in Raw264.7 cells. CONCLUSION: Taken together, these data suggest that apelin-13 administration ameliorates LPS-induced acute lung injury by suppressing ROS formation, as well as by inhibiting the NF-κB pathway and the activation of the NLRP3 inflammasome in the lungs.

Apelin inhibits the proliferation and migration of rat PASMCs via the activation of PI3K/Akt/mTOR signal and the inhibition of autophagy under hypoxia.

Apelin is highly expressed in the lungs, especially in the pulmonary vasculature, but the functional role of apelin under pathological conditions is still undefined. Hypoxic pulmonary hypertension is the most common cause of acute right heart failure, which may involve the remodeling of artery and regulation of autophagy. In this study, we determined whether treatment with apelin regulated the proliferation and migration of rat pulmonary arterial smooth muscle cells (SMCs) under hypoxia, and investigated the underlying mechanism and the relationship with autophagy. Our data showed that hypoxia activated autophagy significantly at 24 hrs. The addition of exogenous apelin decreased the level of autophagy and further inhibited pulmonary arterial SMC (PASMC) proliferation via activating downstream phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/the mammalian target of Rapamycin (mTOR) signal pathways. The inhibition of the apelin receptor (APJ) system by siRNA abolished the inhibitory effect of apelin in PASMCs under hypoxia. This study provides the evidence that exogenous apelin treatment contributes to inhibit the proliferation and migration of PASMCs by regulating the level of autophagy.

Nerve growth factor improves functional recovery by inhibiting endoplasmic reticulum stress-induced neuronal apoptosis in rats with spinal cord injury.

BACKGROUND: Endoplasmic reticulum (ER) stress-induced apoptosis plays a major role in various diseases, including spinal cord injury (SCI). Nerve growth factor (NGF) show neuroprotective effect and improve the recovery of SCI, but the relations of ER stress-induced apoptosis and the NGF therapeutic effect in SCI still unclear. METHODS: Young adult female Sprague-Dawley rats's vertebral column was exposed and a laminectomy was done at T9 vertebrae and moderate contusion injuries were performed using a vascular clip. NGF stock solution was diluted with 0.9% NaCl and administered intravenously at a dose of 20 µg/kg/day after SCI and then once per day until they were executed. Subsequently, the rats were executed at 1d, 3 d, 7d and 14d. The locomotor activities of SCI model rats were tested by the 21-point Basso-Beattie-Bresnahan (BBB) locomotion scale, inclined plane test and footprint analysis. In addition, Western blot analysis was performed to identify the expression of ER-stress related proteins including CHOP, GRP78 and caspase-12 both in vivo and in vitro. The level of cell apoptosis was determined by TUNEL in vivo and Flow cytometry in vitro. Relative downstream signals Akt/GSK-3ß and ERK1/2were also analyzed with or without inhibitors in vitro. RESULTS: Our results demonstrated that ER stress-induced apoptosis was involved in the injury of SCI model rats. NGF administration improved the motor function recovery and increased the neurons survival in the spinal cord lesions of the model rats. NGF decreases neuron apoptosis which measured by TUNEL and inhibits the activation of caspase-3 cascade. The ER stress-induced apoptosis response proteins CHOP, GRP78 and caspase-12 are inhibited by NGF treatment. Meanwhile, NGF administration also increased expression of growth-associated protein 43 (GAP43). The administration of NGF activated downstream signals Akt/GSK-3ß and ERK1/2 in ER stress cell model in vitro. CONCLUSION: The neuroprotective role of NGF in the recovery of SCI is related to the inhibition of ER stress-induced cell death via the activation of downstream signals, also suggested a new trend of NGF translational drug development in the central neural system injuries which involved in the regulation of chronic ER stress.

FGF10 protects against LPS-induced epithelial barrier injury and inflammation by inhibiting SIRT1-ferroptosis pathway in acute lung injury in mice.

Pulmonary alveolar epithelial cell injury is considered the main pathological and physiological change in acute lung injury. Ferroptosis in alveolar epithelial cells is one of crucial factors contributing to acute lung injury (ALI). Therefore, reducing ferroptosis and repair epithelial barrier is very necessary. More and more evidence suggested that FGF10 plays an important role in lung development and repair after injury. However, the relationship between FGF10 and ferroptosis remains unclear. This study aims to explore the regulatory role of FGF10 on ferroptosis in ALI. Differential gene expression analysis indicated that genes associated with ferroptosis showed that FGF10 can significantly alleviate LPS induced lung injury and epithelial barrier damage by decreasing levels of malonaldehyde(MDA), and lipid ROS. SIRT1 activator (Resveratrol) and inhibitor (EX527) are used in vivo showed that FGF10 protects ferroptosis of pulmonary epithelial cells through SIRT1 signal. Furthermore, knockdown of FGFR2 gene reduced the protective effect of FGF10 on acute lung injury in mice and SIRT1 activation. After the application of NRF2 inhibitor ML385 in vitro, the results showed that SIRT1 regulated the expression of ferroptosis related proteins NRF2, GPX4 and FTH1 are related to activation of NRF2. These data indicate that SIRT-ferroptosis was one of the critical mechanisms contributing to LPS-induced ALI. FGF10 is promising as a therapeutic candidate against ALI through inhibiting ferroptosis.

Critical role of checkpoint kinase 1 in spinal cord injury-induced motor dysfunction in mice.

Spinal cord injury (SCI) is a devastating neurotraumatic condition characterized by severe motor dysfunction and paralysis. Accumulating evidence suggests that DNA damage is involved in SCI pathology. However, the underlying mechanisms remain elusive. Although checkpoint kinase 1 (Chk1)-regulated DNA damage is involved in critical cellular processes, its role in SCI regulation remains unclear. This study aimed to explore the role and potential mechanism of Chk1 in SCI-induced motor dysfunction. Adult female C57BL/6J mice subjected to T9-T10 spinal cord contusions were used as models of SCI. Western blotting, immunoprecipitation, histomorphology, and Chk1 knockdown or overexpression achieved by adeno-associated virus were performed to explore the underlying mechanisms. Levels of p-Chk1 and γ-H2AX (a cellular DNA damage marker) were upregulated, while ferroptosis-related protein levels, including glutathione peroxidase 4 (GPX4) and x-CT were downregulated, in the spinal cord and hippocampal tissues of SCI mice. Functional experiments revealed increased Basso Mouse Scale (BMS) scores, indicating that Chk1 downregulation promoted motor function recovery after SCI, whereas Chk1 overexpression aggravated SCI-induced motor dysfunction. In addition, Chk1 downregulation reversed the SCI-increased levels of GPX4 and x-CT expression in the spinal cord and hippocampus, while immunoprecipitation assays revealed strengthened interactions between p-Chk1 and GPX4 in the spinal cord after SCI. Finally, Chk1 downregulation promoted while Chk1 overexpression inhibited NeuN cellular immunoactivity in the spinal cord after SCI, respectively. Collectively, these preliminary results imply that Chk1 is a novel regulator of SCI-induced motor dysfunction, and that interventions targeting Chk1 may represent promising therapeutic targets for neurotraumatic diseases such as SCI.

Apelin-13 improves pulmonary epithelial barrier function in a mouse model of LPS-induced acute lung injury by inhibiting Chk1-mediated DNA damage.

Apelin-13, a type of active peptide, can alleviate lipopolysaccharide (LPS)-induced acute lung injury (ALI). However, the specific mechanism is unclear. Cell cycle checkpoint kinase 1 (Chk1) plays an important role in DNA damage. Here, we investigated the regulatory effect of Apelin on Chk1 in ALI. Chk1-knockout and -overexpression mice were used to explore the role of Chk1 in LPS-induced ALI mice treated with or without Apelin-13. In addition, A549 cells were also treated with LPS to establish a cell model. Chk1 knockdown inhibited the destruction of alveolar structure, the damage of lung epithelial barrier function, and DNA damage in the ALI mouse model. Conversely, Chk1 overexpression had the opposite effect. Furthermore, Apelin-13 reduced Chk1 expression and DNA damage to improve the impaired lung epithelial barrier function in the ALI model. However, the high expression of Chk1 attenuated the protective effect of Apelin-13 on ALI. Notably, Apelin-13 promoted Chk1 degradation through autophagy to regulate DNA damage in LPS-treated A549 cells. In summary, Apelin-13 regulates the expression of Chk1 by promoting autophagy, thereby inhibiting epithelial DNA damage and repairing epithelial barrier function.

An integrated transcriptomic and computational analysis for biomarker identification in gastric cancer.

This report describes an integrated study on identification of potential markers for gastric cancer in patients' cancer tissues and sera based on: (i) genome-scale transcriptomic analyses of 80 paired gastric cancer/reference tissues and (ii) computational prediction of blood-secretory proteins supported by experimental validation. Our findings show that: (i) 715 and 150 genes exhibit significantly differential expressions in all cancers and early-stage cancers versus reference tissues, respectively; and a substantial percentage of the alteration is found to be influenced by age and/or by gender; (ii) 21 co-expressed gene clusters have been identified, some of which are specific to certain subtypes or stages of the cancer; (iii) the top-ranked gene signatures give better than 94% classification accuracy between cancer and the reference tissues, some of which are gender-specific; and (iv) 136 of the differentially expressed genes were predicted to have their proteins secreted into blood, 81 of which were detected experimentally in the sera of 13 validation samples and 29 found to have differential abundances in the sera of cancer patients versus controls. Overall, the novel information obtained in this study has led to identification of promising diagnostic markers for gastric cancer and can benefit further analyses of the key (early) abnormalities during its development.

Antioxidant mitoquinone ameliorates EtOH-LPS induced lung injury by inhibiting mitophagy and NLRP3 inflammasome activation.

Chronic ethanol abuse is a systemic disorder and a risk factor for acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD). However, the mechanisms involved are unknown. One explanation is that ethanol produces damaging reactive oxygen species (ROS) and disturbs the balance of mitochondria within the lungs to promote a pro-injury environment. We hypothesized that targeting an antioxidant to the mitochondria would prevent oxidative damage and attenuate EtOH-LPS-induced lung injury. To test this, we investigated the effects of mitochondria-targeted ubiquinone, Mitoquinone (MitoQ) on ethanol-sensitized lung injury induced by LPS. Lung inflammation, ROS, mitochondria function, and mitophagy were assessed. We demonstrated that chronic ethanol feeding sensitized the lung to LPS-induced lung injury with significantly increased reactive oxygen species ROS level and mitochondrial injury as well as lung cellular NLRP3 inflammasome activation. These deleterious effects were attenuated by MitoQ administration in mice. The protective effects of MitoQ are associated with decreased cellular mitophagy and NLRP3 inflammasome activation in vivo and in vitro. Taken together, our results demonstrated that ethanol aggravated LPS-induced lung injury, and antioxidant MitoQ protects from EtOH-LPS-induced lung injury, probably through reducing mitophagy and protecting mitochondria, followed by NLRP3 inflammasome activation. These results will provide the prevention and treatment of ethanol intake effects with new ideas.

FGF10 ameliorates lipopolysaccharide-induced acute lung injury in mice via the BMP4-autophagy pathway.

Introduction: Damage to alveolar epithelial cells caused by uncontrolled inflammation is considered to be the main pathophysiological change in acute lung injury. FGF10 plays an important role as a fibroblast growth factor in lung development and lung diseases, but its protective effect against acute lung injury is unclear. Therefore, this study aimed to investigate protective effect and mechanism of FGF10 on acute lung injury in mice. Methods: ALI was induced by intratracheal injection of LPS into 57BL/6J mice. Six hours later, lung bronchoalveolar lavage fluid (BALF) was acquired to analyse cells, protein and the determination of pro-inflammatory factor levels, and lung issues were collected for histologic examination and wet/dry (W/D) weight ratio analysis and blot analysis of protein expression. Results: We found that FGF10 can prevent the release of IL-6, TNF-α, and IL-1ß, increase the expression of BMP4 and autophagy pathway, promote the regeneration of alveolar epithelial type Ⅱ cells, and improve acute lung injury. BMP4 gene knockdown decreased the protective effect of FGF10 on the lung tissue of mice. However, the activation of autophagy was reduced after BMP4 inhibition by Noggin. Additionally, the inhibition of autophagy by 3-MA also lowered the protective effect of FGF10 on alveolar epithelial cells induced by LPS. Conclusions: These data suggest that the protective effect of FGF10 is related to the activation of autophagy and regeneration of alveolar epithelial cells in an LPS-induced ALI model, and that the activation of autophagy may depend on the increase in BMP4 expression.

[Inhibition of Beclin 1 enhances apoptosis by H2O2 in glioma U251 cells].

Oxidative stress could induce apoptosis and autophagy process simultaneously, but the role of autophagy is still not clear. Beclin 1, a key gene regulating the preautophagosome formation, is involved in the injury induced by oxidative stress. To observe the role of autophagy in H2O2-induced injury of U251 cells, the recombinant plasmid Psilencer3.1-siRNA-Beclin 1 was transfected into U251 cells by eukaryotic cell transfection technique. Plasmid vector and cell culture medium were used as negative and control groups respectively. The cells were collected 24 h later, and the cell total protein was extracted to detect Beclin 1, Bcl-2 and Bax protein expressions by Western blot. After the Beclin 1-siRNA cells were treated with 1 mmol/L H2O2, the autophagic vacuoles in the cells were stained with monodansylcadaverine (MDC), and the cell apoptotic ratio was determined with PI/Annexin V-FITC staining by flow cytometry analysis. The results showed that the synthetic siRNA decreased the expression of Beclin 1 protein significantly, but had no obvious effect on the levels of Bcl-2 and Bax protein expressions. Compared with those in the control group, the autophagic vacuoles, the level of LC3-II protein expression and the percentage of apoptotic cells increased (P < 0.05) in 1 mmol/L H2O2 group. In Beclin 1-siRNA + H2O2 group, autophagic vacuoles and the levels of LC3-II protein expression decreased obviously, the percentage of apoptotic cells increased significantly compared with that in 1 mmol/L H2O2 group (P < 0.05). H2O2 and autophagy inhibitor 3-methyladenine (3-MA) combination also increased the percentage of apoptotic cells obviously (P < 0.05). These results revealed that the transfection of Psilencer3.1-siRNA-Beclin 1 effectively inhibited the expression of Beclin 1 protein expression, degraded the autophagy level and increased the apoptotic rate in U251 cells under oxidative stress, which was coincident with the effect of autophagy inhibitor 3-MA. This study suggests that autophagy is a cell protective role in oxidative stress process, and the inhibition of autophagy may enhance apoptosis.

Apelin-13-Mediated AMPK ameliorates endothelial barrier dysfunction in acute lung injury mice via improvement of mitochondrial function and autophagy.

Maintaining the pulmonary endothelial barrier that prevents the exudation of inflammatory factors and proteins is the key to the treatment of acute lung injury (ALI). Apelin-13 plays an important role in vascular diseases; however, the protective effects of Apelin-13 on ALI with pulmonary endothelial barrier are unknown. Therefore, mice and human umbilical vein endothelial cells (HUVECs) were injured by LPS following Apelin-13 administration. ALI mice showed reduced pulmonary vascular permeability, adhesion junction, mitochondrial function, mitochondrial biogenesis, and autophagy compared to the control group. Apelin-13 administration in ALI mice ameliorated LPS-induced lung injury, pulmonary vascular permeability, mitochondrial function, and promoted autophagic flux in mice and HUVECs. However, the effect of Apelin-13 was reduced after AMPK inhibition using Compound C. These data suggest that Apelin-13 ameliorates pulmonary vascular permeability in mice with ALI induced by LPS, which may be related to enhanced phosphorylation of AMPK to regulate mitochondrial function and autophagy.

Effects of plant polyphenols on ovarian follicular reserve in aging rats.

The pool of ovarian primordial follicles is established during embryonic development or at birth. During the development from primordial to primary, secondary, and antral follicles, only a small portion of follicles can mature and successfully ovulate; the others are destined to degenerate through apoptotic or atretic loss. As aging advances, females ultimately enter the cessation phase of the estrous cycle and are no longer capable of fertilization. The presumption is that if we can slow down the process of folliculogenesis or decrease follicle loss, females may have a larger ovarian follicular reserve and a longer reproductive lifespan. In our study, rats underwent intragastric administration with tea polyphenols, quercetin (meletin), genistein, or resveratrol, once a day for 4 months (from age 12 to 15 months), to test whether they have positive effects on follicular reserve or ovarian functions. The results showed that rats treated with tea polyphenols (27.8 +/- 3.2) and quercetin (36.5 +/- 4.1) had a comparable number of healthy follicles to those of controls (26.9 +/- 3.8), although significantly fewer atretic follicles were observed in the tea polyphenol group (43.4 +/- 5.9 vs 79.7 +/- 7.5; p < 0.001). Remarkably, both genistein- and resveratrol-treated rats had more healthy follicles (respectively, 42.8 +/- 3.9, p < 0.05; and 51.9 +/- 6.4, p < 0.001) and fewer atretic follicles (respectively, 58.4 +/- 8.0, p < 0.05; and 51.0 +/- 6.2, p < 0.01) than controls. These results indicate that genistein and resveratrol can increase the ovarian follicular reserve and prolong the ovarian lifespan in rats, and their positive effects may be not only due to their intervention in the transition from primordial to primary follicle, but also due to the inhibiting effect on follicular atresia.

[Effects of Apelin-13 on barrier injury of human umbilical vein endothelial cells induced by LPS].

Objective: To investigate the effects of Apelin-13 on barrier function injury of human umbilical vein endothelial cells (HUVECs) induced by LPS. Methods: The HUVECs cultured in vitro were divided into 4 groups: Control group, LPS group, Apelin-13+LPS group, Apelin-13 group. HUVECs were treated by 5 µg/ml LPS for 24 h to replicate the model with endothelial barrier impaired. Apelin-13 at the concentration of 1 µmol/L was given 30 min before LPS treatment. The cell viabillity of HUVECs was measured by CCK-8 assay. Protein expressions of VE-cadherin and F-actin were measured by Western blot and immunofluorescence. Nuclear factor κB p65(NF-κB p65) was detected by immunofluorescence. Results: Compared with the control group, the cell viabillity of HUVECs and protein expression of VE-cadherin were decreased by LPS, but the protein expression of F-actin and activation of NF-κB p65 were increased by LPS. These effects were attenuated by Apelin-13 administration. Conclusion: Apelin-13 ameliorates LPS-induced barrier function injury of HUVECs, which may be related to the inhibition of inflammation.

The Antioxidant MitoQ Protects Against CSE-Induced Endothelial Barrier Injury and Inflammation by Inhibiting ROS and Autophagy in Human Umbilical Vein Endothelial Cells.

Chronic obstructive pulmonary disease (COPD) is a common disease characterized by persistent airflow limitation. Pulmonary vascular endothelial barrier injury and inflammation are increasingly considered to be important pathophysiological processes in cigarette smoke extract (CSE)-induced COPD, but the mechanism remains unclear. To identify the cellular mechanism of endothelial barrier injury and inflammation in CSE-treated human umbilical vein endothelial cells (HUVECs), we investigated the effect of the mitochondrion-targeting antioxidant mitoquinone (MitoQ) on endothelial barrier injury and inflammation. We demonstrated that MitoQ restored endothelial barrier integrity by preventing VE-cadherin disassembly and actin cytoskeleton remodeling, as well as decreased inflammation by the NF-κB and NLRP3 inflammasome pathways in endothelial cells. In addition, MitoQ also maintained mitochondrial function by reducing the production of ROS and excess autophagy. Inhibition of autophagy by 3-MA protected against cytotoxicity that was induced by CSE in HUVECs. Overall, our study indicated that mitochondrial damage is a key promoter in the induction of endothelial barrier dysfunction and inflammation by CSE. The protective effect of MitoQ is related to the inhibition of ROS and excess autophagy in CSE-induced HUVEC injury.

Chloroquine Promotes the Recovery of Acute Spinal Cord Injury by Inhibiting Autophagy-Associated Inflammation and Endoplasmic Reticulum Stress.

Spinal cord injury (SCI) is a severe nervous system disease that may lead to lifelong disability. Studies have shown that autophagy plays a key role in various diseases; however, the mechanisms regulating cross-talk between autophagy, inflammation, and endoplasmic reticulum (ER) stress during SCI recovery remain unclear. This study was designed to investigate the mechanism by which chloroquine (CQ) inhibits autophagy-associated inflammation and ER stress in rats during their recovery from acute SCI. We evaluated the locomotor function, level of autophagy, and levels of inflammatory cytokines and ER-stress-associated proteins and examined the degradation of the key regulator of inflammation inhibitor of kappa B alpha (I-κBα) through autophagy by analyzing the colocalization of I-κBα, p62, and microtubule-associated protein 1 light chain 3-II. In addition, overexpression of the p62 and activating transcription factor 4 (ATF4) silencing plasmids was used to verify the important roles for autophagic degradation and ER stress. In this study, locomotor function is improved, and autophagy and inflammation are significantly inhibited by, CQ treatment in the model rats. In addition, CQ significantly inhibits the degradation of ubiquitinated I-κBα and blocks the nuclear translocation of nuclear factor kappa B p65 and expression of inflammatory factors. Overexpression of p62 increases I-κBα degradation and improves inflammatory responses. Moreover, CQ treatment also inhibits the activation of ER stress in the rat SCI model, and the ATF4 signaling pathway is required for ER-stress-induced activation of autophagy. These findings reveal a novel mechanism underlying the beneficial effects of CQ on the recovery of SCI, particularly the mechanisms regulating cross-talk between autophagy, inflammation, and ER stress.

[Effect of autophagy inhibitor chloroquine on acute alcoholinduced liver disease].

OBJECTIVES: To investigate the role of autophagy inhibitor chloroquine (CQ) in acute ethanol-induced liver injury and its mechenism. METHODS: Twenty-one C57BL/6 male mice were randomly divided into three groups:control group, ethanol group, CQ + ethanol group (n=7). Mice in ethanol group were administered 33% (v/v) ethanol at a dose of 4.5 g/kg body weight. Ethanol-induced liver steatosis in each group was detected by hematoxylin and eosin staining. Hepatic lipid accumulation was detected by staining with Oil red O. Hepatic tissue triglyceride (TG) levels, serum aspartate aminotransferase(AST) and alanine aminotransferase(ALT) were determined by biochemical assays. Protein expression of microtubule-associated protein 1 light chain 3(LC3) and nuclear factorκB p65(NF-κB p65) were measured by Western blot and immunofluorescence. Pro-inflammatory factors tumor necrosis factor-α(TNF-α)、interleukin 6(IL-6) were detected by ELISA. RESULTS: Compared with control group, ethanol induced liver injury proved by accumulation of hepatic lipids, TG levels, AST and ALT activities were significantly increased by ethanol, protein expression of LC3-Ⅱ was also markedly increased by ethanol. Compared with ethanol group, addition of CQ increased furtherthe level of LC3-Ⅱexpression, and TG amount, serum AST and ALT activities, and the expression of NF-κB p65, TNF-αand IL-6. CONCLUSIONS: Acute ethanol-intake could induce liver steatosis and inflammation, and autophagy inhibitor CQ exacerbatedethanol-induced liver injury, suggested that autophagy might be protective effect in acute ethanol-induced liver disease.

Activation of autophagy attenuates EtOH-LPS-induced hepatic steatosis and injury through MD2 associated TLR4 signaling.

Autophagy serves as a protective mechanism to degrade damaged organelles and proteins. Acute alcohol exposure is known to activate the hepatic autophagy response, whereas chronic alcohol exposure slows autophagosome formation along with an elevation of gut-derived endotoxin. In the current study, we examined whether lipopolysaccharide (LPS) administration decreased autophagic response in the liver of mice treated by short-term alcohol and whether activation of autophagy by rapamycin attenuates EtOH-LPS-induced liver steatosis and injury. We demonstrated that ten-day alcohol feeding primed the liver to LPS-induced lipid accumulation and liver injury with significantly increased hepatic steatosis and serum AST level as well as hepatic cellular NF-κB activation. LPS increased alcohol-mediated reactive oxygen species (ROS) formation while reducing autophagy activation. These deleterious effects were attenuated by rapamycin administration in mice. The protective effects of rapamycin are associated with decreased cellular MD2/TLR4 expression and interaction in Raw264.7 cells. Taken together, our results demonstrated that enhanced gut-derived LPS decreases the hepatic autophagosome numbers in response to alcohol exposure, and activation of autophagy by rapamycin protects from EtOH-LPS-induced liver injury, probably through reduced macrophage expression and interaction of TLR4/MD2 signaling complex.

4-PBA inhibits LPS-induced inflammation through regulating ER stress and autophagy in acute lung injury models.

Acute lung injury (ALI) is a common clinical disorder that causes substantial health problems worldwide. An excessive inflammatory response is the central feature of ALI, but the mechanism is still unclear, especially the role of endoplasmic-reticulum (ER) stress and autophagy. To identify the cellular mechanism of lung inflammation during lipopolysaccharide (LPS)-induced mouse model of ALI, we investigated the influence of classic ER stress inhibitor 4-phenyl butyric acid (4-PBA) on ER stress and autophagy, which partially affect the activation of inflammation, both in LPS-induced ALI mouse model and human alveolar epithelial cell model. We demonstrated that 4-PBA, which further prevented the activation of the NF-κB pathway, decreased the release of the pro-inflammatory mediators IL-1ß, TNF-α and IL-6, significantly inhibited LPS-activated ER stress. Moreover, it was found that autophagy was also decreased by the treatment of 4-PBA, which may play a protective role in ALI models through the classical AKT/mTOR signaling pathway. Inhibition of autophagy by 3-MA exacerbates cytotoxicity induced by LPS in A549 alveolar epithelial cells. Taken together, our study indicated that ER stress is a key promoter in the induction of inflammation by LPS, the protective effect of 4-PBA is related to the inhibition of ER stress and autophagy in LPS-induced ALI models. Furthermore, the role of autophagy that contributes to cell survival may depend on the activation of ER stress.