Lipopolysaccharide-induced Acute Liver Injury Research Articles

Isoechinulin B, a natural product from Antarctic fungus, attenuates acute liver injury by inhibiting excessive cell adhesion

Abnormal cell adhesion between leukocytes and endothelial cells is closely associated with the development of numerous inflammation-related diseases, with adhesion molecules playing a crucial role. The disruption of cell adhesion directly or indirectly inhibits excessive cell adhesion and thus produces a therapeutic effect. However, there are only a few clinically available antagonists of cell adhesion. One of the biggest challenges is the development of novel and efficient cell adhesion inhibitors. Recently, the anti-inflammatory pharmacological activity of natural products of microbial origin has also received increasing attention. Here, we obtained a potential cell adhesion inhibitor isoechinulin B, an indole diketopiperazine derivative, from the Antarctic fungus Aspergillus sp. CPCC 401072, which is active against cell adhesion. Isoechinulin B decreased the expression of vascular endothelial adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) by inhibiting the activation of the NF-κB signaling pathway, thereby inhibiting cell adhesion between leukocytes and endothelial cells to reduce macrophage infiltration in the liver and significantly attenuate lipopolysaccharide-induced acute liver injury in mice. ConclusionIsoechinulin B is a novel cell adhesion inhibitor derived from fungi found in extreme environments.

Hesperetin derivative 2a inhibits lipopolysaccharide-induced acute liver injury in mice via downregulation of circDcbld2.

Acute liver injury (ALI) is a complex, life-threatening inflammatory liver disease, and persistent liver damage leads to rapid decline and even failure of liver function. However, the pathogenesis of ALI is still not fully understood, and no effective treatment has been discovered. Recent evidence shows that many circular RNAs (circRNAs) are associated with the occurrence of liver diseases. In this study we investigated the mechanisms of occurrence and development of ALI in lipopolysaccharide (LPS)-induced ALI mice. We found that expression of the circular RNA circDcbld2 was significantly elevated in the liver tissues of ALI mice and LPS-treated RAW264.7 cells. Knockdown of circDcbld2 markedly alleviates LPS-induced inflammatory responses in ALI mice and RAW264.7 cells. We designed and synthesized a series of hesperidin derivatives for circDcbld2, and found that hesperetin derivative 2a (HD-2a) at the concentrations of 2, 4, 8 μM effectively inhibited circDcbld2 expression in RAW264.7 cells. Administration of HD-2a (50, 100, 200 mg/kg. i.g., once 24 h in advance) effectively relieved LPS-induced liver dysfunction and inflammatory responses. RNA sequencing analysis revealed that the anti-inflammatory and hepatoprotective effects of HD-2a were mediated through downregulating circDcbld2 and suppressing the JAK2/STAT3 pathway. We conclude that HD-2a downregulates circDcbld2 to inhibit the JAK2/STAT3 pathway, thereby inhibiting the inflammatory responses in ALI. The results suggest that circDcbld2 may be a potential target for the prevention and treatment of ALI, and HD-2a may have potential as a drug for the treatment of ALI.

The Protective Effect of Broccoli Seed Extract against Lipopolysaccharide-Induced Acute Liver Injury via Gut Microbiota Modulation and Sulforaphane Production in Mice.

Broccoli seed extract (BSE) is rich in glucoraphanin (GRP), which may be transformed by intestinal microbes into sulforaphane (SFN), a compound with strong anti-inflammatory and antioxidant activities. Liver injury usually presents with inflammation and oxidative damage. Thus, dietary BSE supplementation may be an effective approach for alleviating liver injury. In this study, a mouse lipopolysaccharide (LPS)-induced acute liver injury model was used to evaluate the preventive effect of BSE and explore the relevant mechanisms. Compared with the LPS model group, the mice in the BSE group showed significantly lower activities of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) and higher levels of catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Meanwhile, BSE significantly reduced the levels of pro-inflammatory cytokines (including IL-6 and TNF-α) in the liver and increased the level of anti-inflammatory factor (IL-10), indicating that BSE had a good preventive effect on acute liver injury. Additionally, after BSE intervention, the diversity of intestinal microbiota in the mice was higher than that in the LPS model group. The relative abundance of Akkermansia and Lactobacillus increased, while the relative abundance of Xylanophilum decreased. A correlation analysis revealed that the activities of SOD, GSH-Px, CAT and levels of IL-10 were positively correlated with the relative abundance of Lactobacillus. Furthermore, sulforaphane (SFN) and (Sulforaphane-N-Acetyl-Cysteine) SFN-NAC were detected in the urine of the mice after BSE intervention. Both q-PCR and an immunohistochemical analysis showed that BSE significantly regulated the expression level of the NF-κB (IκB-α, NF-κB) and Nrf2 (Nrf2, p-Nrf2 and HO-1) signaling pathways in the liver. In conclusion, BSE was shown to reduce LPS-induced acute liver injury through the conversion of glucoraphanin into sulforaphane and the regulation of the gut microbiota composition. These results suggest that BSE could be a promising ingredient in functional foods.

Forsythiaside A Alleviates Lipopolysaccharide-Induced Acute Liver Injury through Inhibiting Endoplasmic Reticulum Stress and NLRP3 Inflammasome Activation.

The liver is the primary site of inflammation caused by bacterial endotoxins in sepsis, and septic acute liver injury (SALI) is usually associated with poor outcomes in sepsis. Forsythiaside A (FTA), an active constituent of Forsythia suspensa, has been reported to have anti-inflammatory properties, antioxidant properties, and protective properties against neuroinflammation, sepsis, and edema. Therefore, the purpose of the present study was to examine FTA's potential effects on lipopolysaccharide (LPS)-induced SALI in mice. Our results indicated that pretreatment with FTA significantly attenuated aspartate aminotransferase (AST) and aminoleucine transferase (ALT) levels in plasma, ameliorated histopathological damage, inhibited hepatocyte apoptosis, diminished the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6 in the liver from mice exposed to LPS. Furthermore, our data showed that the administration of LPS resulted in robust endoplasmic reticulum (ER) stress response, as evidenced by glucose-regulated protein 78 (GRP78) upregulation, phosphorylated-protein kinase R-like ER kinase (p-PERK) activation, elF2α phosphorylation, and activating transcription factor 4 (ATF4) and CHOP overexpression in the liver. This, in turn, led to nucleotide-binding oligomerization domain-like receptor pyrin domain containing 3 (NLRP3) inflammasome activation, including the cleavage of caspase-1, secretion of IL-1β, and pyroptotic cell death in the liver specimens. Importantly, the ER stress response induced by the LPS challenge was blocked by FTA administration. Correspondingly, NLRP3 inflammasome activation was significantly ameliorated by the pretreatment with FTA. Thus, we demonstrated that FTA pretreatment could protect mice from LPS-induced SALI, and its protective effects were possibly mediated by inhibiting ER stress response and subsequent NLRP3 inflammasome activation.

Chitinase 3 like 1 deficiency ameliorates lipopolysaccharide-induced acute liver injury by inhibition of M2 macrophage polarization

Chitinase 3-like-1 protein (CHI3L1) is involved in various infectious diseases, especially sepsis. Aberrant CHI3L1 expression potentially plays a critical role in chronic inflammation because a considerable number of macrophages are associated with immune/inflammatory diseases. In this study, we examined the effect of CHI3L1 on hepatic sepsis injury using a lipopolysaccharide (LPS)-induced model. LPS-treated CHI3L1 knockout (KO) mice exhibited a higher survival rate than LPS-treated CHI3L1 wild-type (WT) mice. In addition, hepatic injury-related enzyme levels (aspartate transaminase, alanine transaminase, and lactate dehydrogenase) decreased in CHI3L1 KO mice sera, suggesting attenuated LPS-induced septic liver damage in CHI3L1 KO mice. A greater reduction in the mRNA and protein expressions of M2 polarization markers, such as MRC1, ARG1, IL-10, and IL-4, was observed in LPS-induced CHI3L1 KO mice livers than in LPS-induced WT mice livers. Nonetheless, no change in the mRNA and protein expressions of M1 polarization markers, such as INOS, CD86, TNF-α, and IL6, was noted in LPS-induced CHI3L1 KO mice livers compared with those in LPS-induced WT and KO mice. Similar to the in vivo scenario, liver CHI3L1 depletion in LPS-treated HEP3B cells significantly decreased M2 polarization marker protein expression. However, M1 polarization marker protein expression did not differ significantly. These results suggest that CHI3L1 depletion decreases M2 macrophage polarization, and this effect is potentially associated with the alleviation of liver sepsis in CHI3L1 KO mice.

Potential Probiotic Properties of Blautia producta Against Lipopolysaccharide-Induced Acute Liver Injury.

Blautia is a genus of anaerobic microbe extensively present in the intestine and feces of mammals. This study aims to investigate the influence of Blautia producta to prevent lipopolysaccharide (LPS)-induced acute liver injury (ALI) and elaborate on its hepatoprotective mechanisms. B. producta D4 and DSM2950 pretreatment decreased the activities of serum aspartate transferase (AST), and alanine transaminase (ALT) in mice with LPS treatment significantly decreased the levels of inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6) and increased the activities of antioxidative superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px). Compared with the model group, B. producta D4 and B. producta DSM2950 pretreatment slightly increased the levels of cecal propionic acid, isobutyric acid, butyric acid, valeric acid, and isovaleric acid (p > 0.05). Metagenomic analysis showed that B. producta D4 and DSM2950 pretreatment remarkably increased the relative abundance of [Eubacterium] xylanophilum group, Lachnospira, Ruminiclostridium, Ruminiclostridium 9, Coprococcus 2, Odoribacter, Roseburia, Alistipes, and Desulfovibrio in ALI mice, and their abundance is negatively related to the levels of inflammatory TNF-α, IL-1β, and IL-6 as revealed by Spearman's correlation analysis. Moreover, transcription and immunohistochemistry analysis revealed that B. producta D4 and B. producta DSM2950 intervention remarkably suppressed the transcription and expression levels of hepatic Tlr4, MyD88, and caspase-3 (p < 0.05). These data indicated that B. producta may be a good candidate for probiotics in the prevention of ALI.

Inhibition of Chitinase-3-like-1 expression by K284 ameliorates lipopolysaccharide-induced acute liver injury through down regulation of CXCL3

Chitinase 3 like 1 protein (CHI3L1) is involved in various types of infectious disease, especially sepsis. Aberrant expression of CHI3L1 could play a critical role in inflammation and immune responses. Previously, we found that compound K284 has the highest binding activity to CHI3L1. In this study, we investigated the effect of K284 on liver injury during sepsis using a lipopolysaccharide (LPS)-induced C57BL/6 mouse model. We found that the survival rate was a 65 % in LPS + K284 injected mice whereas it was 0% in LPS-treated mice. The serum levels of hepatic injury-related enzymes were decreased in K284-injected mice, indicating that septic liver damage was alleviated by K284. In addition, expression levels of M2 polarization markers were reduced in liver tissues of K284-injected mice. Depletion of CHI3L1 in LPS-treated THLE-2 cells decreased the expression of M2 polarization marker proteins. We investigated the major pathway involved in the observed effects and found that CXCL3 expression is correlated with that of CHI3L1. We found that the expression of CXCL3 was lowered in liver tissues of LPS + K284-treated mice compared with LPS-treated mice. M2 polarization-related cytokine levels were increased by the combination of LPS and recombinant CXCL3, but decreased by K284. M2 polarization-related cytokines, CHI3L1 and CXCL3 expression levels were decreased by CXCL3 siRNA, and further decreased by combination treatment of CXCL3 siRNA and K284. Therefore, CXCL3 might be a significant chemokine involved in the reduction of LPS-induced liver injury during sepsis by K284. Our findings indicate that K284 could be a suitable treatment for sepsis like hepatic injury.

Malvidin protects against lipopolysaccharide-induced acute liver injury in mice via regulating Nrf2 and NLRP3 pathways and suppressing apoptosis and autophagy

Sepsis-related acute liver injury (ALI) is a fatal disease associated with many complications. Recent studies indicate that malvidin, an active flavonoid, has multiple bioactivities including anti-oxidant and anti-inflammation. However, the protective roles of malvidin against LPS-induced ALI are unknown. The purpose of this research is to explore whether malvidin has biological activities on LPS-induced ALI in mice and the underlying mechanisms. Male C57 mice were injected intraperitoneally with malvidin for five days and the mice were euthanized 6 h after LPS (10 mg/kg body weight) intraperitoneal injection. Multiple methods of H&E staining, biochemical kits, qRT-PCR assay, western blotting analysis, TUNEL and transmission electron microscope (TEM) were used. Results showed that decreased ALT, AST levels and alleviated histopathological damage of liver tissue were observed in malvidin pretreatment group in mice. Then, malvidin prevented LPS-induced reduction of antioxidant enzyme activities such as superoxide dismutase (SOD), glutathione peroxidase (GSH-PX) and catalase (CAT) via up-regulating nuclear factor E2-related factor2 (Nrf2) pathway. In addition, in malvidin pretreatment groups, mRNA levels of pro-inflammatory cytokines (TNF-α，IL-1β, IL-6) and protein levels of NOD-like receptor protein 3 (NLRP3) inflammasome in the liver were significantly down-regulated. We also found that the malvidin could reduce the expression of apoptosis key protein and TUNEL-labeled apoptotic hepatocytes. Furthermore, malvidin inhibited the protein expression of ATG5, p62 and the ratio of LC3-II/LC3-I. In conclusion, our study firstly suggests that malvidin is a potentially protective agent against LPS-induced ALI through up-regulating Nrf2 signaling pathway, suppressing NLRP3 inflammasome and inhibiting apoptosis and autophagy.

Bifidobacterium longum BL-10 with Antioxidant Capacity Ameliorates Lipopolysaccharide-Induced Acute Liver Injury in Mice by the Nuclear Factor-κB Pathway.

Bifidobacterium longum is frequently utilized and has broad prospects for preventing liver injury. The current research assessed the antioxidant capacity of B. longum BL-10 and probed its mechanism for ameliorating lipopolysaccharide (LPS)-induced acute liver injury (ALI). B. longum BL-10-encoded 15 antioxidant genes showed strong reducing power activity and scavenging activity of DPPH, hydroxyl radicals, and superoxide anions. The intragastric administration of B. longum BL-10 resulting in a marked reduction in liver function indicators (alanine aminotransferase, aspartate aminotransferase, total bilirubin, and total bile acid) and proinflammatory cytokines (TNF-α, IFN-γ, and IL-6) was indicative of ALI recovery. Following 16s RNA analysis, B. longum BL-10 significantly altered the richness of genera, as for the Escherichia-Shigella, Lachnospiraceae_NK4A136_group, and Clostridia_UCG-014, dramatically contributing to the formation of acetic acid and butyric acid. Meanwhile, their metabolites regulated the TLR4/NF-κB signaling pathways to alleviate hepatic injury symptoms. Overall, all the results demonstrated that B. longum BL-10 had excellent efficiency in preventing LPS-induced ALI.

Lactobacillus paracasei CCFM1223 Protects against Lipopolysaccharide-Induced Acute Liver Injury in Mice by Regulating the "Gut-Liver" Axis.

Background: Lactobacillus paracasei CCFM1223, a probiotic previously isolated from the healthy people’s intestine, exerts the beneficial influence of preventing the development of inflammation. Methods: The aim of this research was to explore the beneficial effects of L. paracasei CCFM1223 to prevent lipopolysaccharide (LPS)-induced acute liver injury (ALI) and elaborate on its hepatoprotective mechanisms. Results: L. paracasei CCFM1223 pretreatment remarkably decreased the activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in mice with LPS treatment and remarkably recovered LPS-induced the changes in inflammatory cytokines (tumor necrosis factor-α (TNF-α), transforming growth factor-β (TGF-β), interleukin (IL)-1β, IL-6, IL-17, IL-10, and LPS) and antioxidative enzymes activities (total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT)). Metagenomic analysis showed that L. paracasei CCFM1223 pretreatment remarkably increased the relative abundance of Catabacter compared with the LPS group but remarkably reduced the relative abundance of [Eubacterium] xylanophilum group, ASF356, Lachnospiraceae NK4A136 group, and Lachnoclostridium, which is closely associated with the inflammation cytokines and antioxidative enzymes. Furthermore, L. paracasei CCFM1223 pretreatment remarkably increased the colonic, serum, and hepatic IL-22 levels in ALI mice. In addition, L. paracasei CCFM1223 pretreatment remarkably down-regulated the hepatic Tlr4 and Nf-kβ transcriptions and significantly up-regulated the hepatic Tlr9, Tak1, Iκ-Bα, and Nrf2 transcriptions in ALI mice. Conclusions: L. paracasei CCFM1223 has a hepatoprotective function in ameliorating LPS-induced ALI by regulating the “gut–liver” axis.

Effect of MiR-423-5p expression on the severity of lipopolysaccharide-induced acute liver injury, inflammatory response and immune function in mice

Purpose: To investigate the biological functions of miR-423-5p in a mouse model with lipopolysaccharide (LPS)-induced acute liver injury.Methods: Sixty male C57BL/6 mice were randomized into control group (n = 20), LPS group (n = 20) and LPS + miR-423-5p mimic group (n = 20). The levels of pro-inflammatory cytokines and apoptosisassociated proteins in the liver tissues were determined. Finally, the survival of mice was recorded within 7 days after the injection of LPS.Results: Overexpression of miR-423-5p improved the liver function of septic mice, and decreased the content of ALT, AST and LDH. Furthermore, overexpression of miR-423-5p also lowered the levels of the oxidative stress markers 4-HNE and MDA, and raised the content of anti-oxidative enzymes SOD and GSH-Px in the liver tissues of septic mice (p &lt; 0.05). The levels of inflammation and apoptosis in the liver of mice in LPS + miR-423-4p mimic group were lower than those in the LPS group (p &lt; 0.05). The overexpression of miR-432-5p increased CD4+ and CD8+ T cells in the spleen of septic mice (p &lt; 0.05), thereby reducing immunosuppression.Conclusion: The expression of miR-423-5p is low in septic mice with liver injury, but its overexpression alleviates acute liver injury and inflammatory responses, and also enhances immune function in mice. Therefore, it has the potential to serve as a targeted drug for the management of liver injury.

Lactobacillus plantarum KLDS1.0386 with antioxidant capacity ameliorates the lipopolysaccharide-induced acute liver injury in mice by NF-κB and Nrf2 pathway

The Lactobacillus is of great interest as a natural antioxidant to ameliorate liver injury for its antioxidant capacity. In a previous experiment, Lactobacillus plantarum KLDS 1.0386 was excellent in adhesion and anti-inflammation. This research assessed the antioxidant capacity of L. plantarum KLDS 1.0386 and how it ameliorates the LPS-induced acute liver injury. In vitro results showed that L. plantarum KLDS 1.0386 had potential antioxidant capacity with 27 genes, and it had better capacities in hydroxyl radicals scavenging and lipid antioxidant than the reference strain L. plantarum WCFS1 (P < 0.05). In vivo results, L. plantarum KLDS 1.0386 significantly reduced hepatic tissue injury, pro-inflammatory cytokines (TNF-α, IL-6), myeloperoxidase (MPO) activities and biochemical indicators of hepatotoxicity (ALT, AST, ALP) (P < 0.05), compared with the LPS-treated mice. Moreover, L. plantarum KLDS 1.0386 increased the relative abundance of the genera, including Lachnospiraceae_NK4A136_group, Muribaculaceae and Alistipes, which significantly increased the level of acetic acid and butyric acid (P < 0.05). The results also showed L. plantarum KLDS 1.0386 significantly adjusted the expression of HO-1, NQO1, CAT, NF-κB, TLR4 and IκB-α in the liver (P < 0.05). Overall, these results indicated that L. plantarum KLDS 1.0386 had great functionality in reducing LPS-induced acute liver injury.

Paramylon from Euglena gracilis Prevents Lipopolysaccharide-Induced Acute Liver Injury.

Acute liver injury (ALI) is a life-threatening syndrome with high mortality and lacks effective therapies. Rodents under LPS (lipopolysaccharide)/D-Gal (D-galactosamine) stress mimic ALI by presenting dramatically increased inflammation and cell death in the liver. Euglena gracilis, functioning like dietary fiber, is commonly used as a paramylon (Pa)-rich nutritional supplement that has various biological effects such as regulating immune system, anti-obesity, and anti-tumor. Here, we found that Pa or sonicated and alkalized paramylon (SA-Pa) alleviated the LPS/D-Gal-induced hepatic histopathological abnormalities in mice. Compared with Pa, SA-Pa had lower molecular weights/sizes and showed better efficacy in alleviating injury-induced hepatic functions, as well as the transcriptional levels of inflammatory cytokines. Moreover, SA-Pa treatment promoted M2 macrophage activation that enhanced the anti-inflammatory function in the liver, and downregulated STAT3 target genes, such as Fos, Jun, and Socs3 upon the injury. Meanwhile, SA-Pa treatment also alleviated apoptosis and necroptosis caused by the injury. Our results demonstrated that SA-Pa efficiently protected the liver from LPS/D-Gal-induced ALI by alleviating inflammation and cell death.

Chitinase 3 Like 1 Deficiency Ameliorates Lipopolysaccharide-Induced Acute Liver Injury by Inhibition of M2 Macrophage Polarization

Chitinase 3 Like 1 Deficiency Ameliorates Lipopolysaccharide-Induced Acute Liver Injury by Inhibition of M2 Macrophage Polarization

ARRB1 suppresses the activation of hepatic macrophages via modulating endoplasmic reticulum stress in lipopolysaccharide-induced acute liver injury

Acute liver injury (ALI) caused by multiple inflammatory responses is a monocyte-/macrophage-mediated liver injury that is associated with high morbidity and mortality. Liver macrophage activation is a vital event that triggers ALI. However, the mechanism of liver macrophage activation has not been fully elucidated. This study examined the role of β-arrestin1 (ARRB1) in wild-type (WT) and ARRB1-knockout (ARRB1-KO) mouse models of ALI induced by lipopolysaccharide (LPS), and ARRB1-KO mice exhibited more severe inflammatory injury and liver macrophage activation compared to WT mice. We found that LPS treatment reduced the expression level of ARRB1 in Raw264.7 and THP-1 cell lines, and mouse primary hepatic macrophages. Overexpression of ARRB1 in Raw264.7 and THP-1 cell lines significantly attenuated LPS-induced liver macrophage activation, such as transformation in cell morphology and enhanced expression of proinflammatory cytokines (tumor necrosis factor-α, interleukin-1β, and interleukin-6), while downregulation of ARRB1 by small interfering RNA and ARRB1 deficiency in primary hepatic macrophages both aggravated macrophage activation. Moreover, overexpression of ARRB1 suppressed LPS-induced endoplasmic reticulum (ER) stress in liver macrophages, and inhibition of ER stress impeded excessive hepatic macrophage activation induced by downregulation of ARRB1. Our data demonstrate that ARRB1 relieves LPS-induced ALI through the ER stress pathway to regulate hepatic macrophage activation and that ARRB1 may be a potential therapeutic target for ALI.

Prophylactic effect of myricetin and apigenin against lipopolysaccharide-induced acute liver injury.

Liver has an important role in the initiation and progression of multiple organ failure that occurs in sepsis. Many natural active substances can be used to reduce the liver injury caused by sepsis. For this aim, the effects of myricetin and apigenin on mice model of acute liver injury was evaluated in this study. Thirty-six mice were randomly divided into six groups as; control, lipopolysaccharide (LPS) (5mg/kg), LPS + myricetin (100mg/kg), LPS + myricetin (200mg/kg), LPS + apigenin (100mg/kg), and LPS + apigenin (200mg/kg) groups. Myricetin and apigenin were administered orally for 7days, and LPS was administered intraperitoneally only on the 7th day of the study. 24h after LPS application, all animals were sacrificed and serum biochemical parameters, histopathology and oxidative stress and inflammation markers of liver tissue were examined. Myricetin and apigenin pre-treatments increased serum albumin and total protein levels, liver GSH level and catalase and SOD activities and decreased serum ALT, AST, ALP, γ-GT, CRP, total and direct bilirubin levels, liver MPO activity, MDA, NOx, PGE2, TNF-α, IL-1β, and IL-6 levels, iNOS and COX-2 mRNA levels, phosphorylation of NF-κB p65, IκB, and IKK proteins but not p38, ERK, and JNK proteins in LPS-treated mice. Myricetin and apigenin administration also regained the hepatic architecture disrupted during LPS application. Myricetin and apigenin pre-treatments led to reduction of liver injury indices and oxidative stress and inflammatory events and these flavonoids has probably hepatoprotective effects in acute liver injury.

Dynamin-related protein 1 deficiency accelerates lipopolysaccharide-induced acute liver injury and inflammation in mice

Mitochondrial fusion and fission, which are strongly related to normal mitochondrial function, are referred to as mitochondrial dynamics. Mitochondrial fusion defects in the liver cause a non-alcoholic steatohepatitis-like phenotype and liver cancer. However, whether mitochondrial fission defect directly impair liver function and stimulate liver disease progression, too, is unclear. Dynamin-related protein 1 (DRP1) is a key factor controlling mitochondrial fission. We hypothesized that DRP1 defects are a causal factor directly involved in liver disease development and stimulate liver disease progression. Drp1 defects directly promoted endoplasmic reticulum (ER) stress, hepatocyte death, and subsequently induced infiltration of inflammatory macrophages. Drp1 deletion increased the expression of numerous genes involved in the immune response and DNA damage in Drp1LiKO mouse primary hepatocytes. We administered lipopolysaccharide (LPS) to liver-specific Drp1-knockout (Drp1LiKO) mice and observed an increased inflammatory cytokine expression in the liver and serum caused by exaggerated ER stress and enhanced inflammasome activation. This study indicates that Drp1 defect-induced mitochondrial dynamics dysfunction directly regulates the fate and function of hepatocytes and enhances LPS-induced acute liver injury in vivo.

An active marine halophenol derivative attenuates lipopolysaccharide-induced acute liver injury in mice by improving M2 macrophage-mediated therapy

2,4′,5′-Trihydroxyl-5,2′-dibromo diphenylmethanone (LM49), an active halophenol derivative synthesized by our group, which exhibits a broad spectrum of therapeutic properties, such as antioxidant and anti-inflammatory activities. In this study, we found LM49 could obviously attenuate acute liver injury induced by lipopolysaccharide (LPS) in mice by polarizing macrophages. The protective effect was described by reducing the hepatic inflammation and improving hepatic function using aspartate transaminase (AST) and alanine transaminase (ALT) assay. Further study revealed that LM49 pretreatment induced the Kupffer cells (KCs) to M2 polarization and decreased the production of inflammatory cytokines. The action mechanism in RAW 264.7 macrophages showed that LM49 could induce the activation of JAK1/STAT6 signaling pathway and the inhibition of TLR-4/NF-kB axis. Morever, LM49 also upregulated the expression of SOCS1 and FLK-4, which can promote M2 polarization by cooperating with STAT6 and inhibit M1 formation by reducing JAK1/STAT1. Our results suggested that LM49 could protect against LPS-induced acute liver injury in mice via anti-inflammatory signaling pathways and subsequent induction of M2 Kupffer cells. The results provided the first experimental evidence of active halophenols for the anti-inflammatory therapy by targeting M2 macrophages.

Estrogen-Related Receptor γ Agonist DY131 Ameliorates Lipopolysaccharide-Induced Acute Liver Injury.

Sepsis-associated liver dysfunction remains a challenge in clinical practice with high mortality and limited specific therapies. DY131 is a pharmacological agonist of the orphan receptor estrogen-related receptor (ERR) γ which plays a crucial role in regulating energy generation, oxidative metabolism, cell apoptosis, inflammatory responses, etc. However, its role in acute liver injury is unknown. In this study, we evaluated the effect of DY131 on lipopolysaccharide (LPS)-induced liver injury. Mice were pretreated with DY131 through intraperitoneal injection at a dose of 5 mg/kg/day for 3 days prior to LPS challenge (10 mg/kg). 24 h later, they were anesthetized and sacrificed. Blood and liver tissues were collected for further studies. In a separate experiment, mice were treated with saline (vehicle) or DY131 for 3 days to evaluate the toxicity of DY131. We found that ERRγ was downregulated in the liver tissues from LPS-treated mice. Pretreatment with DY131 ameliorated LPS-induced liver injury as demonstrated by reduced liver enzyme release (ALT, AST, and LDH), improved liver morphological damage, and attenuated oxidative stress, inflammation and apoptosis. Meanwhile, DY131 had no significant side effects on hepatic and renal functions in mice. Finally, transcriptomics analysis revealed that the dysregulated pathways associated with inflammation and metabolism were significantly reversed by DY131 in LPS-treated mice, providing more evidence in favor of the protective effect of DY131 against LPS-induced liver injury. Altogether, these findings highlighted the protective effect of DY131 on LPS-induced hepatotoxicity possibly via suppressing oxidative stress, inflammation, and apoptosis.

Clodronate, an inhibitor of the vesicular nucleotide transporter, ameliorates steatohepatitis and acute liver injury

The vesicular nucleotide transporter (VNUT) is responsible for the vesicular storage and release of ATP from various ATP-secreting cells, and it plays an essential role in purinergic signaling. Although extracellular ATP and its degradation products are known to mediate various inflammatory responses via purinoceptors, whether vesicular ATP release affects steatohepatitis and acute liver injury is far less understood. In the present study, we investigated the effects of clodronate, a potent and selective VNUT inhibitor, on acute and chronic liver inflammation in mice. In a model of methionine/choline-deficient diet-induced non-alcoholic steatohepatitis (NASH), the administration of clodronate reduced hepatic inflammation, fibrosis, and triglyceride accumulation. Clodronate also protected mice against high-fat/high-cholesterol diet-induced steatohepatitis. Moreover, prophylactic administration of clodronate prevented d-galactosamine and lipopolysaccharide-induced acute liver injury by reducing inflammatory cytokines and hepatocellular apoptosis. In vitro, clodronate inhibited glucose-induced vesicular ATP release mediated by VNUT and reduced the intracellular level and secretion of triglycerides in isolated hepatocytes. These results suggest that VNUT-dependent vesicular ATP release plays a crucial role in the recruitment of immune cells, cytokine production, and the aggravation of steatosis in the liver. Pharmacological inhibition of VNUT may provide therapeutic benefits in liver inflammatory disorders, including NASH and acute toxin-induced injury.