Ameliorative effect of Sedum sarmentosum Bunge extract on Tilapia fatty liver via the PPAR and P53 signaling pathway

Sarmentol H derived from Sedum sarmentosum Bunge directly targets FXR to mitigate cholestasis by recruiting SRC-1

BACKGROUND

Farnesoid X receptor (FXR) is a vital receptor for bile acids and plays an important role in the treatment of cholestatic liver disease. In addition to traditional bile acid-based steroidal agonists, synthetic alkaloids are the most commonly reported non-steroidal FXR agonists. Sarmentol H is a nor-sesquiterpenoid obtained from Sedum sarmentosum Bunge, and in vitro screening experiments have shown that it might be related to the regulation of the FXR pathway in a previous study.

PURPOSE

To investigate the therapeutic effects of sarmentol H on cholestasis and to determine whether sarmentol H directly targets FXR to mitigate cholestasis. Furthermore, this study aimed to explore the key amino acid residues involved in the binding of sarmentol H to FXR through site-directed mutagenesis.

METHODS

An intrahepatic cholestasis mouse model was established to investigate the therapeutic effects of sarmentol H on cholestasis. In vitro experiments, including Co-Ip and FXR-EcRE-Luc assays, were performed to assess whether sarmentol H activates FXR by recruiting the receptor coactivator SRC1. CETSA, SIP, DARTS, and ITC were used to determine the binding of sarmentol H to FXR protein. The key amino acid residues for sarmentol H binding to FXR were analyzed by molecular docking and site-directed mutagenesis. Finally, we conducted in vivo experiments on wild-type and Fxr-/- mice to further validate the anticholestatic target of sarmentol H.

RESULTS

Sarmentol H had significant ameliorative effects on the pathological conditions of cholestatic mice induced with ANIT. In vitro experiments suggested that it is capable of activating FXR and regulating downstream signaling pathways by recruiting SRC1. The target validation experiments showed that sarmentol H had the ability to bind to FXR as a ligand (KD = 2.55 μmol/L) and enhance the stability of its spatial structure. Moreover, site-directed mutagenesis revealed that THR292 and TYR365 were key binding sites for sarmentol H and FXR. Furthermore, knockout of the Fxr gene resulted in a significantly higher degree of ANIT-induced cholestatic liver injury than that in wild-type cholestatic mice, and the amelioration of cholestasis or regulatory effects on FXR downstream genes by sarmentol H also disappeared in Fxr-/- cholestatic mice.

CONCLUSION

Sarmentol H is an FXR agonist. This is the first study to show that it exerts a significant therapeutic effect on cholestatic mice, and can directly bind to FXR and activate it by recruiting the coactivator SRC1.

Effects of Fat and Carnitine on the Expression of Carnitine Acetyltransferase and Enoyl-CoA Hydratase Short-Chain 1 in the Liver of Juvenile GIFT (Oreochromis niloticus)

Carnitine acetyltransferase (CAT) and Enoyl-CoA hydratase short-chain 1 (ECHS1) are considered key enzymes that regulate the β-oxidation of fatty acids. However, very few studies have investigated their full length and expression in genetically improved farmed tilapia (GIFT, Oreochromis niloticus), an important aquaculture species in China. Here, we cloned CAT and ECHS1 full-length cDNA via the rapid amplification of cDNA ends, and the expressions of CAT and ECHS1 in the liver of juvenile GIFT were detected in different fat and carnitine diets, as were the changes in the lipometabolic enzymes and serum biochemical indexes of juvenile GIFT in diets with different fat and carnitine levels. CAT cDNA possesses an open reading frame (ORF) of 2167 bp and encodes 461 amino acids, and the ECHS1 cDNA sequence is 1354 bp in full length, the ORF of which encodes a peptide of 391 amino acids. We found that juvenile GIFT had higher lipometabolic enzyme activity and lower blood CHOL, TG, HDL-C, and LDL-C contents when the dietary fat level was 2% or 6% and when the carnitine level was 500 mg/kg. We also found that the expression of ECHS1 and CAT genes in the liver of juvenile GIFT can be promoted by a 500 mg/kg carnitine level and 6% fat level feeding. These results suggested that CAT and ECHS1 may participate in regulating lipid metabolism, and when 2% or 6% fat and 500 mg/kg carnitine are added to the feed, it is the most beneficial to the liver and lipid metabolism of juvenile GIFT. Our results may provide a theoretical basis for GIFT feeding and treating fatty liver disease.

RNA Sequencing (RNA-Seq) Analysis Reveals Liver Lipid Metabolism Divergent Adaptive Response to Low- and High-Salinity Stress in Spotted Scat (Scatophagus argus)

Spotted scat (Scatophagus argus) can tolerate a wide range of salinity fluctuations. It is a good model for studying environmental salinity adaptation. Lipid metabolism plays an important role in salinity adaptation in fish. To elucidate the mechanism of lipid metabolism in the osmoregulation, the liver transcriptome was analyzed after 22 d culture with a salinity of 5 ppt (Low-salinity group: LS), 25 ppt (Control group: Ctrl), and 35 ppt (High-salinity group: HS) water by using RNA sequencing (RNA-seq) in spotted scat. RNA-seq analysis showed that 1276 and 2768 differentially expressed genes (DEGs) were identified in the LS vs. Ctrl and HS vs. Ctrl, respectively. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that the pathways of steroid hormone biosynthesis, steroid biosynthesis, glycerophospholipid metabolism, glycerolipid metabolism, and lipid metabolism were significantly enriched in the LS vs. Ctrl. The genes of steroid biosynthesis (sqle, dhcr7, and cyp51a1), steroid hormone biosynthesis (ugt2a1, ugt2a2, ugt2b20, and ugt2b31), and glycerophospholipid metabolism (cept1, pla2g4a, and ptdss2) were significantly down-regulated in the LS vs. Ctrl. The pathways related to lipid metabolisms, such as fatty acid metabolism, fatty acid biosynthesis, peroxisome proliferator-activated receptor (PPAR) signaling pathway, adipocytokine signaling pathway, fatty acid degradation, and unsaturated fatty acid biosynthesis, were significantly enriched in the HS vs. Ctrl. The genes of unsaturated fatty acid biosynthesis (scd1, hacd3, fads2, pecr, and elovl1) and adipocytokine signaling pathway (g6pc1, socs1, socs3, adipor2, pck1, and pparα) were significantly up-regulated in the HS vs. Ctrl. These results suggest that the difference in liver lipid metabolism is important to adapt to low- and high-salinity stress in spotted scat, which clarifies the molecular regulatory mechanisms of salinity adaptation in euryhaline fish.

Network pharmacology analysis on mechanism of Jian Pi Qing Gan Yin decoction ameliorating high fat diet-induced non-alcoholic fatty liver disease and validated in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Jian Pi Qing Gan Yin (JPQGY) has been used clinically to relieve non-alcoholic fatty liver disease (NAFLD) in China for decades; however, the underlying mechanisms of JPQGY remain unclear.

AIM OF THE STUDY

We evaluated the effects and mechanisms of JPQGY and hepatic steatosis caused by the middle stage of 13-week-high-fat-diet-induced NAFLD in mice.

MATERIALS AND METHODS

Different dosages of JPQGY (5.5, 11, and 22 g/kg/day) were administered to NAFLD mice simultaneously. Body weight, body mass index (BMI), and liver lipid- and inflammation-related serum indicators were measured enzymatically. Liver samples were stained with Oil Red O and hematoxylin and eosin (H&E). Next, we performed a network pharmacology analysis and verified eight target genes mapping to NAFLD-related lipid metabolism pathways. The mRNA/protein expression was analyzed by real-time polymerase chain reaction (PCR) and western blotting.

RESULTS

JPQGY significantly relieved histological damage (steatosis-inflammation-fibrosis), prevented the downregulation of AMPK and Pparα, and upregulated LXRα, Srebp-1c, F4/80, Nf-κb, and Cyp2e1 in the HFD-induced NAFLD mouse model.

CONCLUSIONS

The present results suggest that chronic treatment with JPQGY ameliorated HFD-induced NAFLD in mice by targeting the first and second phases of hepatic steatosis by stimulating the AMPK/PPARα pathway and inhibiting the LXRα/Srebp1/Nf-κb pathway. Our findings provide evidence that supports the clinical use of this formula for high-fat diet-induced fatty liver disease.

Dietary nano-selenium alleviated intestinal damage of juvenile grass carp (Ctenopharyngodon idella) induced by high-fat diet: Insight from intestinal morphology, tight junction, inflammation, anti-oxidization and intestinal microbiota

In recent years, high-fat diet (HFD) has been widely applied in aquaculture, which reduces the intestinal health of cultured fish. The current study evaluated the protective effects of nano-selenium (nano-Se) on intestinal health of juvenile grass carp (Ctenopharyngodon idella) fed with HFD. A total of 135 experimental fish were fed with a regular diet (Con), a HFD (HFD) and a HFD containing nano-Se at 0.6 mg/kg (HSe) for 10 weeks. The results showed that dietary nano-Se significantly improved the survival rate and feed efficiency which were reduced by HFD in juvenile grass carp (P < 0.05). Also, nano-Se (0.6 mg/kg) supplement alleviated intestinal damage caused by the HFD, thus maintaining the integrity of the intestine. Moreover, it significantly up-regulated the expression of genes related to tight junction (ZO-1, c laudin-3 and o ccludin), anti-oxidization (GPx4a andGPx4b), and the protein of ZO-1 in the intestine of juvenile grass carp, which were depressed by the HFD (P < 0.05). Furthermore, nano-Se supplementation significantly suppressed the expressions of genes related to the inflammation, including inflammatory cytokines (IL-8, IL-1β, IFN-γ, TNF-α and IL-6), signaling molecules (TLR4, p38 MAPK and NF-κB p65), and protein expression of NF-κB p65 and TNF-α in the intestine of juvenile grass carp which were induced by the HFD (P < 0.05). Besides, dietary nano-Se normalized the intestinal microbiota imbalance of juvenile grass carp caused by the HFD through increasing the abundance of the beneficial bacteria, e.g., Fusobacteria. Finally, dietary nano-Se increased the production of short chain fatty acids (SCFA) in the intestine, especially for butyric acid and caproic acid, which were negatively related to the increase of intestinal permeability and inflammation. In summary, supply of nano-Se (0.6 mg/kg) in HFD could effectively alleviate intestinal injury of juvenile grass carp by improving intestinal barrier function and reducing intestinal inflammation and oxidative stress. These positive effects may be due to the regulation of nano-Se on intestinal microbiota and the subsequently increased beneficial SCFA levels.

Sedum sarmentosum Bunge Attenuates Drug-Induced Liver Injury via Nrf2 Signaling Pathway: An Experimental Verification Based on Network Pharmacology Prediction

Purpose

Using network pharmacology and in vivo experiments, we investigated the antidrug-induced liver injury components and functional processes of Sedum sarmentosum Bunge (SSBE).

Methods

The effective components, primary active ingredients, and possible target in the therapy of DILI were predicted using network pharmacology and bioinformatics. APAP was inducing the DILI model. In vivo testing of the pharmacodynamic foundation of SSBE in the treatment of DILI was performed.

Results

The TCMSP database evaluated five main active components and 299 related targets. In addition, 707 differential genes for DILI were obtained from the DisGeNET database, DigSee database, and OMIM database. 61 related targets were mapped to predict the targets of SSBE acting on DILI. The protein-protein interaction (PPI) core network contained 59 proteins, including IL-β, MARK14, SSP1, and MMP9. These genes are closely related to the Nrf2/ARE signaling pathway, and they may play a key role in the hepatoprotective effect of SSBE. Verification experiment results showed that, in the DILI mouse model, SSBE promoted inflammation diminution and regulation of Nrf2-ARE cascade. SSBE protected normal hepatocyte growth and inhibited apoptosis of normal liver cells induced by APAP. SSBE inhibited the expression of Nrf2 and ARE proteins in the liver tissue of the DILI mouse model in vivo.

Conclusion

By modulating the Nrf2 signaling pathway, the active components in SSBE may protect against drug-induced liver damage.

Modelling direct and herd protection effects of vaccination against the SARS-CoV-2 Delta variant in Australia

OBJECTIVES

To analyse the outcomes of COVID-19 vaccination by vaccine type, age group eligibility, vaccination strategy, and population coverage.

DESIGN

Epidemiologic modelling to assess the final size of a COVID-19 epidemic in Australia, with vaccination program (Pfizer, AstraZeneca, mixed), vaccination strategy (vulnerable first, transmitters first, untargeted), age group eligibility threshold (5 or 15 years), population coverage, and pre-vaccination effective reproduction number ( R eff v ¯ ) for the SARS-CoV-2 Delta variant as factors.

MAIN OUTCOME MEASURES

Numbers of SARS-CoV-2 infections; cumulative hospitalisations, deaths, and years of life lost.

RESULTS

Assuming R eff v ¯ = 5, the current mixed vaccination program (vaccinating people aged 60 or more with the AstraZeneca vaccine and people under 60 with the Pfizer vaccine) will not achieve herd protection unless population vaccination coverage reaches 85% by lowering the vaccination eligibility age to 5 years. At R eff v ¯ = 3, the mixed program could achieve herd protection at 60-70% population coverage and without vaccinating 5-15-year-old children. At R eff v ¯ = 7, herd protection is unlikely to be achieved with currently available vaccines, but they would still reduce the number of COVID-19-related deaths by 85%.

CONCLUSION

Vaccinating vulnerable people first is the optimal policy when population vaccination coverage is low, but vaccinating more socially active people becomes more important as the R eff v ¯ declines and vaccination coverage increases. Assuming the most plausible R eff v ¯ of 5, vaccinating more than 85% of the population, including children, would be needed to achieve herd protection. Even without herd protection, vaccines are highly effective in reducing the number of deaths.

Metabolism and antioxidation regulation of total flavanones from Sedum sarmentosum Bunge against high-fat diet-induced fatty liver disease in Nile tilapia (Oreochromis niloticus)

Diet-induced fatty liver is a considerable threaten to fish aquaculture due to the popularity of the high-fat diet (HFD) feeding. Our study aims to investigate the effects of flavanones from Sedum sarmentosum Bunge (FSSB) on the liver function to identify a potential treatment for HFD-induced fatty liver disease. Physiological and pathological indicators were tested in the liver of Nile tilapia (Oreochromis niloticus) and results showed parameters including lipid metabolites, redox parameters, and inflammatory factors could be adequately restored to normal level by addition of 150 mg/kg FSSB to HFD. Proteomics analysis was performed in liver tissues from tilapia with normal diet (ND), HFD, and HFD+FSSB. Totally, 51 upregulated proteins and 77 downregulated proteins were identified in HFD groups and 67 proteins of them were restored after treated with FSSB. Bioinformatics analysis showed that differentially expressed proteins (DEPs) in HFD+FSSB150 group compared with HFD group are mainly enriched in acety-CoA metabolic process, adenosine-triphosphate (ATP) biosynthetic process, lipid metabolic process, and phospholipid metabolic process. The dysregulated proteins were involved in peroxidosome proliferators-activated receptor (PPAR) signaling pathway, fat digestion and absorption, and immune system. The quantitative real-time PCR (qRT-PCR) assay further revealed that the expression of GST, PPARα, PPARγ, and multiple-inflammatory cytokines could be also reversed in HFD group under the treatment of 150 mg/kg FSSB. Our findings demonstrated FSSB is efficient for the treatment of fatty liver disease through regulation of lipid metabolism and antioxidation in Nile tilapia, providing a new treatment of non-alcoholic fatty liver disease (NAFLD) in fish aquaculture.

Comparative transcriptomic analysis reveals an association of gibel carp fatty liver with ferroptosis pathway

Background

Fatty liver has become a main problem that causes huge economic losses in many aquaculture modes. It is a common physiological or pathological phenomenon in aquaculture, but the causes and occurring mechanism are remaining enigmatic.

Methods

Each three liver samples from the control group of allogynogenetic gibel carp with normal liver and the overfeeding group with fatty liver were collected randomly for the detailed comparison of histological structure, lipid accumulation, transcriptomic profile, latent pathway identification analysis (LPIA), marker gene expression, and hepatocyte mitochondria analyses.

Results

Compared to normal liver, larger hepatocytes and more lipid accumulation were observed in fatty liver. Transcriptomic analysis between fatty liver and normal liver showed a totally different transcriptional trajectory. GO terms and KEGG pathways analyses revealed several enriched pathways in fatty liver, such as lipid biosynthesis, degradation accumulation, peroxidation, or metabolism and redox balance activities. LPIA identified an activated ferroptosis pathway in the fatty liver. qPCR analysis confirmed that gpx4, a negative regulator of ferroptosis, was significantly downregulated while the other three positively regulated marker genes, such as acsl4, tfr1 and gcl, were upregulated in fatty liver. Moreover, the hepatocytes of fatty liver had more condensed mitochondria and some of their outer membranes were almost ruptured.

Conclusions

We reveal an association between ferroptosis and fish fatty liver for the first time, suggesting that ferroptosis might be activated in liver fatty. Therefore, the current study provides a clue for future studies on fish fatty liver problems.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07621-2.

Systemic pharmacology understanding of the key mechanism of Sedum sarmentosum Bunge in treating hepatitis

Sedum sarmentosum Bunge is a Traditional Chinese Medicine that is widely used in treating hepatitis, whereas the detailed mechanisms have not been fully interpreted. A systemic pharmacology method including absorption, distribution, metabolism and elimination screening, drug targeting, interaction network plotting, and enrichment analysis was applied for exploring the underlying mechanisms of Sedum sarmentosum Bunge in the treatment of hepatitis. A total of 47 ingredients were identified in Sedum sarmentosum Bunge, and 5 active ingredients (DFV, isorhamnetin, beta-sitosterol, luteolin and quercetin) were screened out with the criteria of oral bioavailability (OB) ≥ 30% and drug-likeness (DL) ≥ 0.18. Those 5 ingredients interacted with 170 targets, 163 of which were hepatitis-related. By compound-target-disease network plotting, protein-protein interaction network plotting and enrichment analysis, the pathways that the 5 ingredients engaged in during hepatitis development and progression were investigated, such as threonine-protein kinase signaling. The integrated systemic pharmacology analysis facilitates the in-depth understanding of Sedum sarmentosum Bunge in the hepatitis treatment, which also paves the way for further knowledge of the molecular mechanism of Sedum sarmentosum Bunge in treating hepatitis.

Functional analysis of Epinephelus coioides peroxisome proliferative-activated receptor α (PPARα): Involvement in response to viral infection

Peroxisome proliferative-activated receptor α (PPARα) belongs to the superfamily of nuclear receptors (NR). Studies have demonstrated that PPARα functions in energy metabolism, hepatic function, immune response, cell cycle, and apoptosis. In teleost fish, few studies have investigated the role of PPARα in the immune response. In this study, the grouper PPARα gene (EcPPARα) was investigated for its role in viral infection. The open reading frame of EcPPARα encoded a protein of 469 amino acids and contained an N-terminal domain (NTD), a DNA-binding domain (DBD), a hinge region, and a C-terminal ligand-binding domain (LBD). Phylogenetic analysis revealed that EcPPARα was most closely related to homologous genes in Sander lucioperca and Perca flavescens. Upon challenge with SGIV (Singapore grouper iridovirus) and RGNNV (Red-spotted grouper nervous necrosis virus), EcPPARα expression levels were significantly upregulated in different tissues. Subcellular localization analysis showed that the EcPPARα protein localized throughout the cytoplasm and nucleus with diffuse intracellular expression patterns, which is consistent with the localization pattern of mammalian PPARs. Based on morphological observation of cytopathic effect (CPEs), viral gene expression mRNAs, and virus titer assays, the results presented here showed that an overexpression of EcPPARα promoted SGIV production in grouper spleen cells. Overexpression of EcPPARα significantly inhibited the expression of several cytokines, including interferon-related genes (IFN-γ, ISG15, MXI, MXII, MAVS and MDA5), inflammatory cytokines (IL-1β, IL-6, IL-8, TNF-α) and Toll like receptor adaptors (TRAF6 and MyD88). Luciferase activity of IFN-α, IFN-γ, ISRE and NF-κB promoters was also significantly decreased in EcPPARα overexpression cells. Due to these detected interferon-related genes and inflammatory cytokines play important antiviral effect against SGIV in grouper, we speculated that the promotion effect of EcPPARα on SGIV replication may be caused by down-regulation of interferon and inflammatory response. In addition, through apoptotic body observation, capspase-3 activity detection, and flow cytometry analysis, it was found that overexpression of EcPPARα promoted SGIV-induced apoptosis in fathead minnow (FHM) cells. These data may increase an understanding of the role of PPARα in fish antiviral immune responses and apoptosis.

Transcriptomic comparison of liver tissue between Anqing six-end-white pigs and Yorkshire pigs based on RNA sequencing

Chinese indigenous pig and Western commercial pig breeds show different patterns of lipid metabolism, fat deposition, and fatty acid composition; for these reasons, they have become vitally important models of energy metabolism and obesity in humans. To compare the mechanisms underlying lipid metabolism between Yorkshire pigs (lean type) and Anqing six-end-white pigs (obese type), the liver transcriptomes of six castrated boars with a body weight of approximately 100 kg (three Yorkshire and three Anqing) were analyzed by RNA-seq. The total number of reads produced for each liver sample ranged from 47.05 to 62.6 million. Among 362 differentially expressed genes, 142 were up-regulated and 220 were down-regulated in Anqing six-end-white pigs. Based on these data, 79 GO terms were significantly enriched. The top 10 (the 10 with lowest corrected P-value) significantly enriched GO terms were identified, including lipid metabolic process and carboxylic acid metabolic process. Pathway analysis revealed three significantly enriched KEGG pathways including PPAR signaling pathway, steroid hormone biosynthesis, and retinol metabolism. Based on protein–protein interaction networks, multiple genes responsible for lipid metabolism were identified, such as PCK1, PPARA, and CYP7A1, and these were considered promising candidate genes that could affect porcine liver lipid metabolism and fat deposition. Our results provide abundant transcriptomic information that will be useful for animal breeding and biomedical research.

The Impacts of Herbal Medicines and Natural Products on Regulating the Hepatic Lipid Metabolism

The dysregulation of hepatic lipid metabolism is one of the hallmarks in many liver diseases including alcoholic liver diseases (ALD) and non-alcoholic fatty liver diseases (NAFLD). Hepatic inflammation, lipoperoxidative stress as well as the imbalance between lipid availability and lipid disposal, are direct causes of liver steatosis. The application of herbal medicines with anti-oxidative stress and lipid-balancing properties has been extensively attempted as pharmaceutical intervention for liver disorders in experimental and clinical studies. Although the molecular mechanisms underlying their hepatoprotective effects warrant further exploration, increasing evidence demonstrated that many herbal medicines are involved in regulating lipid accumulation processes including hepatic lipolytic and lipogenic pathways, such as mitochondrial and peroxisomal β-oxidation, the secretion of very low density lipoprotein (VLDL), the non-esterified fatty acid (NEFA) uptake, and some vital hepatic lipogenic enzymes. Therefore, in this review, the pathways or crucial mediators participated in the dysregulation of hepatic lipid metabolism are systematically summarized, followed by the current evidences and advances in the positive impacts of herbal medicines and natural products on the lipid metabolism pathways are detailed. Furthermore, several herbal formulas, herbs or herbal derivatives, such as Erchen Dection, Danshen, resveratrol, and berberine, which have been extensively studied for their promising potential in mediating lipid metabolism, are particularly highlighted in this review.

Sedum sarmentosum Bunge extract ameliorates lipopolysaccharide- and D-galactosamine-induced acute liver injury by attenuating the hedgehog signaling pathway via regulation of miR-124 expression

Background

Sedum sarmentosum is traditionally used to treat various inflammatory diseases in China. It has protective effects against acute liver injury, but the exact mechanism of such effects remains unclear. This study investigated the protective effects of S. sarmentosum extract on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury in mice and the mechanism of such effects.

Methods

Mice were randomly divided into control, treatment, model, and model treatment groups. Acute liver injury was induced in model mice via intraperitoneal injection of LPS and D-GalN with doses of 10 μg/kg of LPS and 500 mg/kg, respectively. The mRNA expression levels of miR-124, Hedgehog, Patched (Ptch), Smoothened (Smo), and glioma-associated oncogene homolog (Gli) in liver tissues were determined through RT-PCR, and the protein levels of Hedgehog, Ptch, Smo, Gli, P13k, Akt, HMGB1, TLR4, IkB-α, p-IkB-α, and NF-kB65 were evaluated via Western blot analysis. The serum levels of IL-6, TNF-α, CRP, IL-12, and ICAM-1 were determined via ELISA. TLR4 and NF-κBp65 activity and the levels of DNA-bound NF-KB65 and TLR4 in LPS/D-GalN-induced liver tissues were also determined. We recorded the time of death, plotted the survival curve, and calculated the liver index. We then observed the pathological changes in liver tissue and detected the levels of liver enzymes (alanine aminotransferase [ALT] and aspartate transaminase [AST]) in the serum and myeloperoxidase (MPO) and plasma inflammatory factors in the liver homogenate. Afterward, we evaluated the protective effects of S. sarmentosum extracts on acute liver injury in mice.

Results

Results showed that after S. sarmentosum extract was administered, the expression level of miR-124 increased in liver tissues. However, the protein expression levels of Hedgehog, Ptch, Smo, Gli, P13k, p-Akt, HMGB1, TLR4, p-IκB-α, and NF-κB65 and the mRNA expression levels of Hedgehog, Ptch, Smo, and Gli decreased. The MPO level in the liver, the IL-6, TNF-α, CRP, IL-12, and MMP-9 levels in the plasma, and the serum ALT and AST levels also decreased, thereby reducing LPS/D-GalN-induced liver injury and improving the survival rate of liver-damaged animals within 24 h.

Conclusions

S. sarmentosum extract can alleviate LPS/D-GalN-induced acute liver injury in mice and improve the survival rate of mice. The mechanism may be related to the increase in miR-124 expression, decrease in Hedgehog and HMGB1 signaling pathway activities, and reduction in inflammatory responses in the liver. Hedgehog is a regulatory target for miR-124.

Changes in Physiological Parameters, Lipid Metabolism, and Expression of MicroRNAs in Genetically Improved Farmed Tilapia (Oreochromis niloticus) With Fatty Liver Induced by a High-Fat Diet

Tilapia is susceptible to hepatic steatosis when grown in intensive farming systems. The aim of this study was to explore the mechanism of fatty liver induced by a high-fat diet (HFD) in genetically improved farmed tilapia (GIFT, Oreochromis niloticus). Juvenile GIFT were fed with HFD or a normal-fat diet (NFD) for 60 days. Substantial fat deposition in the liver of HFD-fed GIFT on days 20, 40, and 60 was observed using hematoxylin – eosin staining and oil red O staining. The increased fat deposition was consistent with increased triglyceride (TG) and total cholesterol (TC) levels in the liver of HFD-fed GIFT. There were significant differences (P < 0.05) in serum biochemical indexes (TG, TC, low density lipoprotein-cholesterol, and insulin contents, and alanine aminotransferase activity) between GIFT fed a HFD and GIFT fed a NFD on days 20, 40, and 60. Furthermore, 60 days of a HFD significantly changed (P < 0.05) the hepatic fatty acid composition, and led to increased polyunsaturated fatty acid levels and decreased saturated fatty acid and monounsaturated fatty acid levels. Hepatic antioxidant enzyme activities increased by day 20 and then declined, which led to an increase in malondialdehyde contents in the liver of HFD-fed GIFT. Molecular analyses revealed that the microRNAs miR-122, miR-29a, and miR-145-5p were upregulated, whereas miR-34a was downregulated in HFD-fed GIFT. SCD, ELOVL6, and SRD5A2 encode three important enzymes in lipid metabolism, and were identified as potential targets of miRNAs. The transcript levels of hepatic SCD and ELOVL6 were decreased and that of hepatic SRD5A2 was increased in GIFT fed a HFD. Overall, the results of this study revealed a potential link between miRNAs and fatty liver induced by HFD, and suggest that a HFD could lead to excess fat deposition in the GIFT liver, which may disrupt hepatic lipid metabolism and reduce the antioxidant defense capacity.