Veratric acid alleviates liver ischemia/reperfusion injury by activating the Nrf2 signaling pathway

Sakuranetin Prevents Acetaminophen-Induced Liver Injury via Nrf2-Induced Inhibition of Hepatocyte Ferroptosis

Introduction

Oxidative stress is an important cause of acetaminophen (APAP)-induced liver injury (AILI). Sakuranetin (Sak) is an antitoxin from the cherry flavonoid plant with good antioxidant effects. However, whether sakuranetine has a protective effect on APAP-induced liver injury is not clear.

Methods

Mouse and HepG2 cell models of APAP injury were used to investigate the effect of sakuranetin on AILI and its mechanism. Serum transaminase levels, histological changes, inflammatory mediators, oxidative stress, ferroptosis-related markers and Nrf2 signaling pathway proteins were analyzed.

Results

Sakuranetin significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST), as well as inflammatory factor; increased HepG2 activity and decreased cell death; inhibited ROS production, increased glutathione (GSH) content, expression of Glutathione Peroxidase 4 (GPX4) and Solute Carrier Family 7 Member 11 (SLC7A11), and decreased malondialdehyde and Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) expression in mice and HepG2 cells after APAP treatment. Further analysis showed that sakuranetin induced the activation of the NFE2 Like BZIP Transcription Factor 2 (Nrf2) signaling pathway in liver tissue and HepG2 cells and promoted the nuclear translocation of Nrf2. Moreover, the hepatoprotective effect of sakuranetin and its inhibitory effect on ferroptosis were significantly attenuated by the Nrf2 inhibitor ML385.

Conclusion

Sakuranetin alleviates AILI by activating the Nrf2 signaling pathway and inhibiting ferroptosis, and sakuranetin may be a potential therapeutic agent for the treatment of AILI.

Dietary supplement of veratric acid alleviates liver steatosis and reduces abdominal fat deposition in broilers

Nonalcoholic fatty liver disease (NAFLD) and obesity are nutritional metabolic diseases that are prevalent in the poultry industry, and have a negative impact on its functioning. Veratric acid (VA) is a phenolic acid compound extracted from the Chinese herbal medicine Trollius chinensis Bunge, known for its anti-inflammatory and antioxidant properties. In this study, we used chicken hepatocytes (Leghorn male hepatoma cells) and treated with a mixture of oleic acid and palmitic acid as well as Yellow-feathered broilers fed a high-fat diet to examine the impact of VA on liver-lipid metabolism and deposition of abdominal fat. The results showed that VA (1μM) reduced the triglyceride and total cholesterol levels in the chicken hepatocytes (p < 0.05). In the broiler NAFLD model, VA significantly reduced liver TG levels (p < 0.05) without affecting growth performance. Dietary supplementation with 0.05% or 0.1% VA supplementation also significantly reduced the mRNA expression levels of key genes involved in the synthesis of fatty acids such as sterol regulatory element-binding protein 1c, fatty acid synthase, and acetyl-CoA carboxylase in broiler livers. In addition, 0.1% VA reduced abdominal fat accumulation and improved blood biochemical indexes in broilers. Network pharmacology analysis suggested that VA may participate in regulating fat metabolism in broilers via the proliferator-activated receptor signaling pathway. Taken together, the study results support VA as a candidate feed additive to provide a novel strategy for preventing NAFLD and excessive fat deposition in chickens.

Current status and perspective on molecular targets and therapeutic intervention strategy in hepatic ischemia-reperfusion injury

Hepatic ischemia‒reperfusion injury (HIRI) is a common and inevitable complication of hepatic trauma, liver resection, or liver transplantation. It contributes to postoperative organ failure or tissue rejection, eventually affecting patient prognosis and overall survival. The pathological mechanism of HIRI is highly complex and has not yet been fully elucidated. The proposed underlying mechanisms include mitochondrial damage, oxidative stress imbalance, abnormal cell death, immune cell hyperactivation, intracellular inflammatory disorders and other complex events. In addition to serious clinical limitations, available antagonistic drugs and specific treatment regimens are still lacking. Therefore, there is an urgent need to not only clarify the exact etiology of HIRI but also reveal the possible reactions and bottlenecks of existing drugs, helping to reduce morbidity and shorten hospitalizations. We analyzed the possible underlying mechanism of HIRI, discussed various outcomes among different animal models and explored neglected potential therapeutic strategies for HIRI treatment. By thoroughly reviewing and analyzing the literature on HIRI, we gained a comprehensive understanding of the current research status in related fields and identified valuable references for future clinical and scientific investigations.

Nepetoidin B Alleviates Liver Ischemia/Reperfusion Injury via Regulating MKP5 and JNK/P38 Pathway

Background

Nepetoidin B (NB) has been reported to possess anti-inflammatory, antibacterial, and antioxidant properties. However, its effects on liver ischemia/reperfusion (I/R) injury remain unclear.

Methods

In this study, a mouse liver I/R injury model and a mouse AML12 cell hypoxia reoxygenation (H/R) injury model were used to investigate the potential role of NB. Serum transaminase levels, liver necrotic area, cell viability, oxidative stress, inflammatory response, and apoptosis were evaluated to assess the effects of NB on liver I/R and cell H/R injury. Quantitative polymerase chain reaction (qPCR) and Western blotting were used to measure mRNA and protein expression levels, respectively. Molecular docking was used to predict the binding capacity of NB and mitogen-activated protein kinase phosphatase 5 (MKP5).

Results

The results showed that NB significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, liver necrosis, oxidative stress, reactive oxygen species (ROS) content, inflammatory cytokine content and expression, inflammatory cell infiltration, and apoptosis after liver I/R and AML12 cells H/R injury. Additionally, NB inhibited the JUN protein amino-terminal kinase (JNK)/P38 pathway. Molecular docking results showed good binding between NB and MKP5 proteins, and Western blotting results showed that NB increased the protein expression of MKP5. MKP5 knockout (KO) significantly diminished the protective effects of NB against liver injury and its inhibitory effects on the JNK/P38 pathway.

Conclusion

NB exerts hepatoprotective effects against liver I/R injury by regulating the MKP5-mediated P38/JNK signaling pathway.

Ferroptosis: a new target for hepatic ischemia-reperfusion injury?

Ischemia-reperfusion injury (IRI) can seriously affect graft survival and prognosis and is an unavoidable event during liver transplantation. Ferroptosis is a novel iron-dependent form of cell death characterized by iron accumulation and overwhelming lipid peroxidation; it differs morphologically, genetically, and biochemically from other well-known cell death types (autophagy, necrosis, and apoptosis). Accumulating evidence has shown that ferroptosis is involved in the pathogenesis of hepatic IRI, and targeting ferroptosis may be a promising therapeutic approach. Here, we review the pathways and phenomena involved in ferroptosis, explore the associations and implications of ferroptosis and hepatic IRI, and discuss possible strategies for modulating ferroptosis to alleviate the hepatic IRI.

6-Gingerol attenuates hepatic ischemia/reperfusion injury through regulating MKP5-mediated P38/JNK pathway

6-Gingerol, the main bioactive compound of ginger, has antioxidant, anti-inflammatory, anti-cancer and neuroprotective effects. However, it is unclear whether 6-Gingerol has protective effects against hepatic ischemia/reperfusion (I/R) injury. In this study, the mouse liver I/R injury model and the mouse AML12 cell hypoxia/reoxygenation (H/R) model were established by pretreatment with 6-Gingerol at different concentrations to explore the potential effects of 6-Gingerol. Serum transaminase levels, liver necrotic area, cell viability, inflammatory response, and cell apoptosis were used to assess the effect of 6-Gingerol on hepatic I/R or cell H/R injury. Quantitative polymerase chain reaction (qPCR) and Western blotting were used to detect the mRNA and protein expression. The results show that 6-Gingerol decreased serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) levels, liver necrosis, inflammatory cytokines IL-1β, IL-6, MCP-1, TNF-α expression, Ly6g+ inflammatory cell infiltration, protein phosphorylation of NF-κB signaling pathway, Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) positive cells, cell apoptosis rate, the protein expression of pro-apoptotic protein BAX and C-Caspase3, increased cell viability, and expression of anti-apoptotic protein BCL-2. Moreover, 6-Gingerol could increase the mRNA and protein expression of mitogen activated protein kinase phosphatase 5 (MKP5) and inhibit the activation of P38/JNK signaling pathway. In MKP5 knockout (KO) mice, the protective effect of 6-gingerol and the inhibition of P38/JNK pathway were significantly weakened. Therefore, our results suggest that 6-Gingerol exerts anti-inflammatory and anti-apoptotic effects to attenuate hepatic I/R injury by regulating the MKP5-mediated P38/JNK signaling pathway.

Histone deacetylase 6 deficiency protects the liver against ischemia/reperfusion injury by activating PI3K/AKT/mTOR signaling

Liver transplantation (LT) is the only effective method to treat end-stage liver disease. Hepatic ischemia-reperfusion injury (IRI) continues to limit the prognosis of patients receiving LT. Histone deacetylase 6 (HDAC6) is a unique HDAC member involved in inflammation and apoptosis. However, its role and mechanism in hepatic IRI have not yet been reported. We examined HDAC6 levels in liver tissue from LT patients, mice challenged with liver IRI, and hepatocytes subjected to hypoxia/reoxygenation (H/R). In addition, HDAC6 global-knockout (HDAC6-KO) mice, adeno-associated virus-mediated liver-specific HDAC6 overexpressing (HDAC6-LTG) mice, and their corresponding controls were used to construct hepatic IRI models. Hepatic histology, inflammatory responses, and apoptosis were detected to assess liver injury. The molecular mechanisms of HDAC6 in hepatic IRI were explored in vivo and in vitro. Moreover, the HDAC6-selective inhibitor tubastatin A was used to detect the therapeutic effect of HDAC6 on liver IRI. Together, our results showed that HDAC6 expression was significantly upregulated in liver tissue from LT patients, mice subjected to hepatic I/R surgery, and hepatocytes challenged by hypoxia/reoxygenation (H/R) treatment. Compared with control mice, HDAC6 deficiency mitigated liver IRI by inhibiting inflammatory responses and apoptosis, whereas HDAC6-LTG mice displayed the opposite phenotype. Further molecular experiments show that HDAC6 bound to and deacetylated AKT and HDAC6 deficiency improved liver IRI by activating PI3K/AKT/mTOR signaling. In conclusion, HDAC6 is a key mediator of hepatic IRI that functions to promote inflammation and apoptosis via PI3K/AKT/mTOR signaling. Targeting hepatic HDAC6 inhibition may be a promising approach to attenuate liver IRI.

Adelmidrol ameliorates liver ischemia-reperfusion injury through activating Nrf2 signaling pathway

Liver ischemia/reperfusion (I/R) injury commonly occurs after various liver surgeries. Adelmidrol, an N- palmitoylethanolamide analog, has anti-inflammatory, anti-oxidant, and anti-injury properties. To investigate whether adelmidrol could reduce liver I/R injury, we established a mouse of liver I/R injury and an AML12 cell hypoxia-reoxygenation model to perform experiments using multiple indicators. Serum ALT and AST levels, and H&E staining were used to measure liver damage; MDA content, superoxide dismutase and glutathione activities, and dihydroethidium staining were used to measure oxidative stress; mRNA expression levels of tumor necrosis factor-α, interleukin (IL)-1β, IL-6, MCP-1, and Ly6G staining were used to measure inflammatory response; and protein expression of Bax, Bcl-2, C-caspase3, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining were used to measure apoptosis. The experimental results showed that adelmidrol reduced liver I/R injury. In addition, adelmidrol pretreatment elevated AML12 cell activity and reduced I/R-and H/R-induced apoptosis, inflammatory injury, and oxidative stress. ML385, an inhibitor of nuclear factor erythroid2-related factor 2 (Nrf2), reverses liver I/R injury attenuated by adelmidrol. These results suggest that adelmidrol ameliorates liver I/R injury by activating the Nrf2 signaling pathway.

Paeonol Attenuates Hepatic Ischemia/Reperfusion Injury by Modulating the Nrf2/HO-1 and TLR4/MYD88/NF-κB Signaling Pathways

Hepatic ischemia/reperfusion (HIR) is the most common type of liver injury following several clinical situations. Modulating oxidative stress and inflammation by Nrf2/HO-1 and TLR4/MYD88/NF-κB pathways, respectively, is involved in alleviating HIR injury. Paeonol is a natural phenolic compound that demonstrates significant antioxidant and anti-inflammatory effects. The present study explored the possible protective effect of paeonol against HIR injury and investigated its possible molecular mechanisms in rats. Rats were randomly divided into four groups: sham-operated control, paeonol-treated sham-operated control, HIR untreated, and HIR paeonol-treated groups. The results confirmed that hepatic injury was significantly aggravated biochemically by elevated serum levels of alanine transaminase and aspartate transaminase, as well as by histopathological alterations, while paeonol reduced the increase in transaminases and alleviated pathological changes induced by HIR. Additionally, paeonol inhibited the HIR-induced oxidative stress in hepatic tissues by decreasing the upraised levels of malondialdehyde and nitric oxide and enhancing the suppressed levels of reduced glutathione and superoxide dismutase activity. Furthermore, paeonol activated the protective antioxidative Nrf2/HO-1 pathway. The protective effect of paeonol was associated with inhibiting the expression of the inflammatory key mediators TLR4, MYD88, NF-κB, and TNF-α. Finally, paeonol inhibited the increased mRNA levels of the pro-apoptotic marker Bax and enhanced the reduced mRNA levels of the anti-apoptotic marker Bcl-2. Taken together, our results proved for the first time that paeonol could protect against HIR injury by inhibiting oxidative stress, inflammation, and apoptosis.

Kaempferol From Penthorum chinense Pursh Attenuates Hepatic Ischemia/Reperfusion Injury by Suppressing Oxidative Stress and Inflammation Through Activation of the Nrf2/HO-1 Signaling Pathway

The purpose of this study is to investigate the protective effect of kaempferol (KAE), the main active monomer from Penthorum chinense Pursh, on hepatic ischemia/reperfusion injury (HI/RI) and its specific mechanism. HI/RI is a common complication closely related to the prognosis of liver surgery, and effective prevention and treatment methods are still unavailable. Ischemia/reperfusion (I/R) injury is caused by tissue damage during ischemia and sustained oxidative stress and inflammation during reperfusion. Penthorum chinense Pursh is a traditional Chinese medicine widely used to treat liver disease since ancient times. Kaempferol (KAE), a highly purified flavonoid active monomer isolated and extracted from Penthorum chinense Pursh, was investigated for its protective effect on HI/RI. Our study indicates that KAE pretreatment alleviated I/R-induced transaminase elevation and pathological changes. Further analysis revealed that KAE pretreatment attenuates I/R-induced oxidative stress (as measured by the content of MDA, SOD and GSH) in vivo and reduces hypoxia/reoxygenation (H/R) -induced reactive oxygen species (ROS) generation in vitro. Meanwhile, KAE inhibits activation of NF-κB/p65 and reduces the release of pro-inflammatory factors (TNF-α and IL-6) to protect the liver from I/R-induced inflammation. Nuclear erythroid 2-related factor 2 (Nrf2) is a crucial cytoprotection regulator because it induces anti-inflammatory, antioxidant, and cytoprotective genes. Therefore, we analyzed the protein levels of Nrf2 and its downstream heme oxygenase-1 (HO-1) in the liver of mice and hepatocytes of humankind, respectively, and discovered that KAE pretreatment activates the Nrf2/HO-1 signaling pathway. In summary, this study confirmed the hepatoprotective effect of KAE on HI/RI, which inhibits oxidative stress and inflammation by activating the Nrf2/HO-1 signaling pathway.

miR‑129‑5p inhibits oxidized low‑density lipoprotein‑induced A7r5 cell viability and migration by targeting HMGB1 and the PI3k/Akt signaling pathway

The mechanisms underlying gene therapy for the treatment of cardiovascular diseases remain to be elucidated. microRNAs (miRs) have been recognized as key regulators in vascular smooth muscle cells, which are involved in the formation of atherosclerosis. The present study aimed to explore the role of miR-129-5p in the regulation of high-mobility group box 1 protein (HMGB1) and the PI3k/Akt signaling pathway, and further explore the role of miR-129-5p in the viability and migration of A7r5 cells induced by oxidized low-density lipoprotein (ox-LDL). Cell viability, viability and migration were determined using Cell Counting Kit-8, colony formation, wound healing and Transwell assays. The expression levels of miR-129-5p and HMGB1 were detected using reverse transcription-quantitative PCR and western blotting. A dual-luciferase assay was used to confirm the association between miR-129-5p and HMGB1. RT-qPCR results in the present study demonstrated that the expression levels of miR-129-5p in A7r5 cells induced by ox-LDL were significantly decreased, compared with the control cells. Moreover, the viability and migration of A7r5 cells induced by ox-LDL were increased compared with control group. Western blot and RT-qPCR results showed that miR-129-5p decreased the expression of HMGB1 in A7r5 cells compared with control group. The present results demonstrated that miR-129-5p inhibited the viability, viability and migration of A7r5 cells induced by ox-LDL, and directly targeted HMGB1 to regulate the PI3k/Akt signaling pathway. In conclusion, miR-129-5p inhibited the PI3k/Akt signaling pathway by directly targeting HMGB1, and reduced the viability, viability and migration of A7r5 cells induced by ox-LDL.