Anti-inflammation and anti-apoptosis effects of growth arrest-specific protein 6 in acute liver injury induced by LPS/D-GalN in mice

Aralia saponin A isolated from Achyranthes bidentata Bl. ameliorates LPS/D-GalN induced acute liver injury via SPHK1/S1P/S1PR1 pathway in vivo and in vitro

OBJECTIVE

Acute liver injury (ALI) refers to a disease in which the liver is affected by factors such as chemical substances, alcohol, and virus infection in a short time, resulting in damage to liver cells. Achyranthes bidentata Bl. with the hepatoprotective activity has attracted great attention. In this study, a pentacyclic triterpenoid (Aralia saponin A, AsA) was isolated from roots of Achyranthes bidentata Bl. and its anti-ALI activity, as well as the mechanisms, were investigated for the first time.

METHODS

AsA (10 or 20 mg/kg, i.g.) was administered over a period of 1 weeks, following which liver injury was induced by LPS (10 µg/kg)/D-GalN (700 mg/kg). H&E staining of liver, Aspartate amino transferase (AST), Alanine transaminase (ALT) and cytokines was employed to investigate ALI relevant features. The mitochondrial morphology and levels of mitochondrial membrane potential (MMP), oxidative stress balance, apoptosis, average fluorescence intensity of 2-DG, natural killer (NK) cells in liver tissues were determined to assess the oxidative stress damage and inflammatory injury. Transcriptomics and metabonomics analysis were employed to clarify the mechanisms. Additionally, the mRNA and protein expression levels of Sphingosine 1-phosphate (S1P), Sphingosine kinase-1 (SPKH1), Sphingosine 1 phosphate receptor 1 (S1PR1), Sphingosine 1 phosphate receptor 3 (S1PR3), TNF receptor associated factor 2 (TRAF-2), Phospho-NF- kappaB p65 (p-P65), NF- kappaB p65 (P65), Proto-oncogene ras (Ras), Ras-related C3 botulinum toxin substrate (Rac), Phospholipase C (PLC), Interleukin 6 (IL-6), Tumor necrosis factor α (TNF-α), Interleukin 1β (IL-1β), Vascular cell adhesion molecule 1 (Vcam1), CC chemokine ligand-2 (Ccl2) were analyzed. The mediating role of SPHK1 in the observed effects caused by AsA was assessed by investigatin SPHK1 transfection silencing/overexpression against AsA in AML12 cells induced by LPS/D-GalN.

RESULTS

AsA can ameliorate liver function, inflammation, mitochondrial structure and oxidative stress in the ALI model. Meanwhile, AsA led to downregulated expression of proteins associated with sphingolipid signaling pathway. Silencing of SPHK1 led to enhanced protective effects of AsA, while over-expression of SPHK1 led to degraded protective effects of AsA in LPS/D-GalN-induced AML12 cells, suggesting that ALI is regulated by active molecules of AsA by means of SPHK1 mediation.

CONCLUSIONS

AsA can ameliorate LPS/D-GalN-induced ALI by inhibiting inflammation and oxidative stress via the SPHK1/S1P/S1PR1 pathway. In this way, a molecular justification is provided for AsA application in ALI treatment.

Luteolin-7-O-rutinoside from Pteris cretica L. var. nervosa attenuates LPS/D-gal-induced acute liver injury by inhibiting PI3K/AKT/AMPK/NF-κB signaling pathway

Pteris cretica L. var. nervosa is one of the most well-known Chinese medicines. Although it is widely used to treat jaundice hepatitis, the main ingredient for its treatment was not thoroughly explored until recently. Essentially, the purpose of this study is to find the monomer compound in Pteris cretica L. var. nervosa, which is most likely to be effective in treating liver injury. Through the model of LPS/D-gal-induced liver injury in mice, the best therapeutic site of the total extract was explored, the chemical components of the parts with the best therapeutic effect were separated, a total of 10 flavonoids were isolated, and the RAW264.7 cells induced by LPS were used as the experimental model to explore the preliminary anti-inflammatory activity of NO production in vitro. Finally, the anti-inflammatory activity and the highest content in this plant Luteolin-7-O-rutinoside (LUT) were selected, as the object of study in vivo. It was found that LUT could not only reduce alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, but also significantly reduce the release of tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β), and inhibit PI3K/AKT/AMPK/NF-κB pathway. In addition, LUT can increase levels of SOD and GSH to reduce oxidative stress. It has an obvious therapeutic effect on acute liver injury induced by LPS/D-gal in mice. Therefore, infer LUT is a functional substance in Pteris cretica L. var. nervosa.

Microbiota diversity in nonalcoholic fatty liver disease and in drug-induced liver injury

The gut microbiota could play a significant role in the progression of nonalcoholic fatty liver disease (NAFLD); however, its relevance in drug-induced liver injury (DILI) remains unexplored. Since the two hepatic disorders may share damage pathways, we analysed the metagenomic profile of the gut microbiota in NAFLD, with or without significant liver fibrosis, and in DILI, and we identified the main associated bacterial metabolic pathways. In the NAFLD group, we found a decrease in Alistipes, Barnesiella, Eisenbergiella, Flavonifractor, Fusicatenibacter, Gemminger, Intestinimonas, Oscillibacter, Parasutterella, Saccharoferementans and Subdoligranulum abundances compared with those in both the DILI and control groups. Additionally, we detected an increase in Enterobacter, Klebsiella, Sarcina and Turicibacter abundances in NAFLD, with significant liver fibrosis, compared with those in NAFLD with no/mild liver fibrosis. The DILI group exhibited a lower microbial bacterial richness than the control group, and lower abundances of Acetobacteroides, Blautia, Caloramator, Coprococcus, Flavobacterium, Lachnospira, Natronincola, Oscillospira, Pseudobutyrivibrio, Shuttleworthia, Themicanus and Turicibacter compared with those in the NAFLD and control groups. We found seven bacterial metabolic pathways that were impaired only in DILI, most of which were associated with metabolic biosynthesis. In the NAFLD group, most of the differences in the bacterial metabolic pathways found in relation to those in the DILI and control groups were related to fatty acid and lipid biosynthesis. In conclusion, we identified a distinct bacterial profile with specific bacterial metabolic pathways for each type of liver disorder studied. These differences can provide further insight into the physiopathology and development of NAFLD and DILI.

Effect of Short-Term Tacrolimus Exposure on Rat Liver: An Insight into Serum Antioxidant Status, Liver Lipid Peroxidation, and Inflammation

Tacrolimus (TAC) is an immunosuppressive drug, optimally used for liver, kidney, and heart transplant to avoid immune rejection. In retrospect, a multitude of studies have reported effects of TAC, such as nephrotoxicity, diabetes, and other complications. However, limited information is available regarding short-term exposure of TAC on the liver. Therefore, the present study was designed to unravel the effects of short-term exposure of TAC on a rat model. The animal model was established by TAC administration for 6, 12, 24, and 48 h time points. Liver histopathological changes were observed with PAS-D, reticulin stain, and immunostaining of PCNA and CK-7 coupled with glycogen quantification in a liver homogenate. TUNEL assay was performed to evaluate the DNA damage in the liver. Concentration of GSH and activities of SOD and CAT in the serum were measured to assess the antioxidant status, whereas liver tissue MDA level was measured as a biomarker of oxidative stress. Hepatic gene expression analysis of IL-10, IL-13, SOCS-2, and SOCS-3 was performed by RT-PCR. Results revealed marked changes in liver architecture of all TAC-treated groups, as evidenced by sinusoid dilation, hepatocyte derangement, glycogen deposition, and collapsed reticulin fibers. Significant increase in PCNA and CK-7 immunostaining along with the presence of TUNEL-positive cells was revealed in treatment groups as compared to the control group. Serum antioxidant enzyme status was markedly decreased, whereas the liver MDA level was increased in TAC treatment groups indicating oxidative stress induction. The gene expression profile of cytokines was significantly upregulated in treatment groups highlighting an inflammatory response. In conclusion, results of the current study propose that even a short-term TAC exposure can induce change in antioxidant status and lipid peroxidation. Therefore, these factors should be considered to avoid and minimize immunosuppression-related issues in a prolonged course of treatment.