Lipid Deposition In Liver Tissue Research Articles

Competitive adsorption of microRNA-532-3p by circular RNA SOD2 activates Thioredoxin Interacting Protein/NLR family pyrin domain containing 3 pathway and promotes pyroptosis of non-alcoholic fatty hepatocytes

ObjectiveThere is a growing body of evidence indicating that pyroptosis, a programmed cell death mechanism, plays a crucial role in the exacerbation of inflammation and fibrosis in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Circular RNAs (circRNAs), functioning as vital regulators within NAFLD, have been shown to mediate the process of cell pyroptosis. This study aims to elucidate the roles and mechanisms of circRNAs in NAFLD.MethodsUtilizing a high-fat diet (HFD)-induced rat model for in vivo experimentation and hepatocytes treated with palmitic acid (PA) for in vitro models, we identified circular RNA SOD2 (circSOD2) as our circRNA of interest through analysis with the circMine database. The expression levels of associated genes and pyroptosis-related proteins were determined using quantitative real-time polymerase chain reaction and Western blotting, alongside immunohistochemistry. Serum liver function markers, cellular inflammatory cytokines, malondialdehyde, lactate dehydrogenase levels, and mitochondrial membrane potential, were assessed using enzyme-linked immunosorbent assay, standard assay kits, or JC-1 staining. Flow cytometry was employed to detect pyroptotic cells, and lipid deposition in liver tissues was observed via Oil Red O staining. The interactions between miR-532-3p/circSOD2 and miR-532-3p/Thioredoxin Interacting Protein (TXNIP) were validated through dual-luciferase reporter assays and RNA immunoprecipitation experiments.ResultsOur findings demonstrate that, in both in vivo and in vitro NAFLD models, there was an upregulation of circSOD2 and TXNIP, alongside a downregulation of miR-532-3p. Mechanistically, miR-532-3p directly bound to the 3'-UTR of TXNIP, thereby mediating inflammation and cell pyroptosis through targeting the TXNIP/NLR family pyrin domain containing 3 (NLRP3) inflammasome signaling pathway. circSOD2 directly interacted with miR-532-3p, relieving the suppression on the TXNIP/NLRP3 signaling pathway. Functionally, the knockdown of circSOD2 or TXNIP improved hepatocyte pyroptosis; the deletion of miR-532-3p reversed the effects of circSOD2 knockdown, and the deletion of TXNIP reversed the effects of circSOD2 overexpression. Furthermore, the knockdown of circSOD2 significantly mitigated the progression of NAFLD in vivo.ConclusioncircSOD2 competitively sponges miR-532-3p to activate the TXNIP/NLRP3 inflammasome signaling pathway, promoting pyroptosis in NAFLD.

Specific knockout of notch-1 attenuates non-alcoholic fatty liver disease by promoting SHP2 phosphorylation.

To investigate the effect of Notch-1 signaling on NAFLD and its molecular mechanism. The lipid deposition in liver tissues was detected by oil red O staining. Western blotting was performed to detect the expressions of SREBP1C, SREBP2, LXR, IL-1β, IL-18, NLRP3, Notch-1, NOX2, NOX4, p-PI3K and p-SHP2 in macrophages, and the expressions of ALIX, CD9, IL-1β and SREBP1C in exosomes. Macrophages in the Notch-1MAC-KO group and Notch-1WT group were treated with FFA, and those in the Notch-1WT+FFA group and Notch-1MAC-KO+FFA group were treated with SHP2 inhibitors PHPS1 and Relaxin. It was observed by oil red O staining that lipid deposition in mice with NAFLD was reduced in the Notch-1MAC-KO group. The results of Western blotting showed that the expressions of ALIX, CD9, IL-1β and SREBP1C in macrophage exosomes were significantly lower in the Notch-1MAC-KO group than in the Notch-1WT group. In macrophages, the expressions of SREBP1C, SREBP2, LXR, IL-1β, IL-18, Notch-1, NOX2, NOX4 and p-PI3K significantly decreased, while the expression of p-SHP2 significantly increased in the Notch-1MAC-KO group compared with the Notch-1WT group. The Notch-1MAC-KO+FFA group had significantly decreased expressions of SREBP1C, NLRP3, IL-1β, IL-18, SREBP2, NOX2, NOX4 and p-PI3K and a significantly increased expression of p-SHP2 compared with the Notch-1WT+FFA group. However, the differences in the above proteins were all eliminated after PHPS1 and Relaxin were added. Specific knockout of Notch-1 attenuates NAFLD, and reduces inflammation and lipid deposition in the liver by promoting SHP2 phosphorylation.

Tilianin alleviates lipid deposition and fibrosis in mice with nonalcoholic steatohepatitis by activating the PPARα/Nnat axis.

The understanding and treatment of nonalcoholic steatohepatitis (NASH) are still very limited. This study reports the therapeutic effect of tilianin on mice with NASH and further explores its possible molecular mechanisms. A mice model of NASH was established using low-dose streptozotocin combined with a high-fat diet and tilianin treatment. Liver function was assessed by determining serum aspartate aminotransferase and alanine aminotransferase in serum. Interleukin (IL)-1β, IL-6, transforming growth factor β1 (TGF-β1), and tumor necrosis factor α (TNF-α) levels in serum were determined. Hepatocyte apoptosis was assessed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining. Oil Red O staining and boron dipyrrin staining were used to determine lipid deposition in liver tissues. Masson staining was used to evaluate liver fibrosis, and immunohistochemistry and western blot analysis were used to determine the expression of target proteins. Tilianin treatment significantly ameliorated liver function, inhibited hepatocyte apoptosis, and reduced lipid deposition and liver fibrosis in mice with NASH. The expression of neuronatin (Nnat) and peroxisome proliferator-activated receptor (PPAR) α was upregulated, whereas that of sterol regulatory element-binding protein 1 (SREBP-1), TGF-β1, nuclear factor (NF)-κB p65, and phosphorylated p65 was downregulated in the liver tissues of mice with NASH after tilianin treatment. The above effects of tilianin were significantly reversed after Nnat knock-down, but its effect on PPARα expression was unaffected. Thus, the natural drug tilianin shows potential in treatig NASH. Its mechanism of action may be related to the targeted activation of PPARα/Nnat, thereby inhibiting the activation of the NF-κB signaling pathway.

Swietenine inhibited oxidative stress through AKT/Nrf2/HO‐1 signal pathways and the liver‐protective effect in T2DM mice: In vivo and in vitro study

Swietenia macrophylla King, belongs to the Meliaceae family, is a valuable medicinal plant and its fruits have been processed commercially to a variety of health foods. The seeds have long been known for their ethnomedicinal significance against these diseases. Swietenine (Swi) was isolated from S. macrophylla and could ameliorate inflammation and oxidative stress. In this study, HepG2 cells induced by H2 O2 were used to construct oxidative stress model in vitro. The aim of this study was to investigate the protective effect of Swi on H2 O2 induced oxidative injury in HepG2 cells and its molecular mechanism, and to explore the effect of Swi on liver injury in db/db mice and its possible mechanism. The results showed that Swi significantly inhibited HepG2 cells viability and reduced oxidative damage in a dose-dependent manner as evidenced by a range of biochemical analysis and immunoblotting study. Moreover, it induced the protein and mRNA expression of HO-1 together with its upstream mediator Nrf2 and activated the phosphorylation of AKT in HepG2 cells. LY294002, a PI3K/AKT inhibitor, significantly suppressed the Nrf2 nuclear translocation and HO-1 expression in H2 O2 induced HepG2 cells treated with Swi. In addition, RNA interference with Nrf2 significantly reduced the expression level of Nrf2 and HO-1 in the nucleus. Swi has a significant protective effect on cell damage in H2 O2 induced HepG2 cells by increasing the antioxidant capacity which is achieved through the AKT/Nrf2/HO-1 pathway. Additionally, in vivo, Swi could protect the liver of type 2 diabetic mice by improving lipid deposition in liver tissue and inhibiting oxidative stress. These findings indicated that Swi can be a promising dietary agent to improve type 2 diabetes.

Empagliflozin activates Sestrin2-mediated AMPK/mTOR pathway and ameliorates lipid accumulation in obesity-related nonalcoholic fatty liver disease.

Empagliflozin (EMPA) therapy has led to improvements in patients with non-alcoholic fatty liver disease (NAFLD). Sestrin2 is a stress-inducible protein that controls the AMPK-mTOR pathway and inhibits oxidative damage in cells. This study investigated the functional implications of EMPA on the multifactorial pathogenesis of NAFLD and potential underlying molecular mechanisms of pathogenesis. An in vitro model of NAFLD was established by treating HepG2 cells with palmitic acid (PA); an in vivo model of NAFLD was generated by feeding C57BL/6 mice a high-fat diet. Investigations of morphology and lipid deposition in liver tissue were performed. Expression patterns of Sestrin2 and genes related to lipogenesis and inflammation were assessed by reverse transcription polymerase chain reaction. Protein levels of Sestrin2 and AMPK/mTOR pathway components were detected by Western blotting. NAFLD liver tissues and PA-stimulated HepG2 cells exhibited excessive lipid production and triglyceride secretion, along with upregulation of Sestrin2 and increased expression of lipogenesis-related genes. EMPA treatment reversed liver damage by upregulating Sestrin2 and activating the AMPK-mTOR pathway. Knockdown of Sestrin2 effectively increased lipogenesis and enhanced the mRNA expression levels of lipogenic and pro-inflammatory genes in PA-stimulated HepG2 cells; EMPA treatment did not affect these changes. Furthermore, Sestrin2 knockdown inhibited AMPK-mTOR signaling pathway activity. The upregulation of Sestrin2 after treatment with EMPA protects against lipid deposition-related metabolic disorders; it also inhibits lipogenesis and inflammation through activation of the AMPK-mTOR signaling pathway. These results suggest that Sestrin2 can be targeted by EMPA therapy to alleviate lipogenesis and inflammation in obesity-related NAFLD.

Establishment and metabonomics analysis of nonalcoholic fatty liver disease model in golden hamster.

The aim is to establish a model of nonalcoholic fatty liver disease (NAFLD) caused by feeding with high-fat, high-fructose, and high-cholesterol diet (HFFCD) in golden hamsters, and to investigate the characteristics of the NAFLD model and metabolite changes of liver tissue. Golden hamsters were fed HFFCD or control diets for six weeks. Body weight, abdominal fat index, and liver index was assessed, serum parameters, hepatic histology, and liver metabolites were examined. The results showed that body weight, abdominal fat, and liver index of hamsters were significantly increased in the model group, the level of serum total cholesterol (TC), triglyceride (TG), and low density lipoprotein-cholesterol (LDL-C) were significantly increased in model group as well, and high density lipoprotein-cholesterol (HDL-C) was significantly decreased. In addition, lipid deposition in liver tissue formed fat vacuoles of different sizes. Metabonomics analysis of the liver showed that the metabolic pathways of sphingolipid, glycerophospholipids, and arginine biosynthesis were disordered in the NAFLD model. The modeling method is simple, short time, and uniform. It can simulate the early fatty liver caused by common dietary factors, and provides an ideal model for the study of the initial pathogenesis and therapeutic drugs for NAFLD.

Efficacy and mechanism of new resource medicinal materia Moringa oleifera leaves against hyperlipidemia

High fat diet induced hyperlipidemia hamster model was used to explore the anti-hyperlipidemia effect of water extract of Moringa oleifera leaves( WEMOL). On this basis,the possible action mechanism was predicted by network pharmacology. Golden hamsters were randomly divided into normal diet group( NFD),high-fat diet group( HFD),simvastatin group,high dose group of WEMOL( HIWEMOL) and low dose group of WEMOL( LOWEMOL). The model was administered simultaneously for 66 days,during which the body weight changes of hamsters were recorded. At the end of the experiment,serum lipid level and serum transaminase level of golden hamsters in each group were detected,and the pathological changes of liver were observed by hematoxylin-eosin( HE) staining. The results showed that WEMOL could significantly decrease the serum total cholesterol( TC),total triglyceride( TG),low density lipoprotein cholesterol( LDL-c) levels,and reduce the lipid deposition in liver tissue,thus improving the hyperlipidemia of golden hamsters. According to the prediction of network pharmacology,219 targets of potential active components of M.oleifera leaves and 185 targets of water-soluble potential active components of M. oleifera leaves for the treatment of hyperlipidemia were obtained separately. The MCODE analysis was performed on the PPI network of 219 targets and 185 targets obtained above and got five and four clusters respectively. The signaling pathway analysis of clusters showed that among the common pathways,nonalcoholic fatty liver,insulin resistance,MAPK signaling pathway,estrogen signaling pathway,cell apoptosis and HIF-1 signaling pathway were associated with hyperlipidemia. In addition,the potential active components of M. oleifera leaves could also inhibit the metabolic inflammation of hyperlipidemia by modulating complement and coagulation cascades signaling pathway,and GSK3 B,F2,AKT1,RELA,SERPINE1 might be the key targets. The water-soluble potential active components of M. oliefera leaves could modulate lipid metabolism by modulating AMPK signaling pathway and JAK-STAT signaling pathway,with PIK3 CB,PIK3 CA,CASP3,AKT1 and BCL2 as the key targets. These results suggested that WEMOL had anti hyperlipidemia effect,and its mechanism might be related to the protein expression regulation of lipid metabolism,nonalcoholic fatty liver disease and atherosclerosis related signaling pathways.

MiR-542-5p Inhibits Hyperglycemia and Hyperlipoidemia by Targeting FOXO1 in the Liver.

PurposeThis research was designed to investigate how miR-542-5p regulates the progression of hyperglycemia and hyperlipoidemia.Materials and MethodsAn in vivo model with diabetic db/db mice and an in vitro model with forskolin/dexamethasone (FSK/DEX)-induced primary hepatocytes and HepG2 cells were employed in the study. Bioinformatics analysis was conducted to identify the expression of candidate miRNAs in the liver tissues of diabetic and control mice. H&E staining revealed liver morphology in diabetic and control mice. Pyruvate tolerance tests, insulin tolerance tests, and intraperitoneal glucose tolerance test were utilized to assess insulin resistance. ELISA was conducted to evaluate blood glucose and insulin levels. Red oil O staining showed lipid deposition in liver tissues. Luciferase reporter assay was used to depict binding between miR-542-5p and forkhead box O1 (FOXO1).ResultsMiR-542-5p expression was under-expressed in the livers of db/db mice. Further in vitro experiments revealed that FSK/DEX, which mimics the effects of glucagon and glucocorticoids, induced cellular glucose production in HepG2 cells and in primary hepatocytes cells. Notably, these changes were reversed by miR-542-5p. We found that transcription factor FOXO1 is a target of miR-542-5p. Further in vivo study indicated that miR-542-5p overexpression decreases FOXO1 expression, thereby reversing increases in blood glucose, blood lipids, and glucose-related enzymes in diabetic db/db mice. In contrast, anti-miR-542-5p exerted an adverse influence on blood glucose and blood lipid metabolism, and its stimulatory effects were significantly inhibited by sh-FOXO1 in normal control mice.ConclusionCollectively, our results indicated that miR-542-5p inhibits hyperglycemia and hyperlipoidemia by targeting FOXO1.

TRUSS inhibition protects against high fat diet (HFD)-stimulated brain injury by alleviation of inflammatory response

High fat diet (HFD)-induced obesity is associated with insulin resistance (IR) and other chronic, diet associated illnesses, including neuroinflammation and brain injury. However, the involvement of inflammatory response in HFD-elicited central nerve injury has yet to be fully determined. Recent studies have indicated that tumor necrosis factor receptor-associated ubiquitous scaffolding and signaling protein (TRUSS), also known as TRPC4AP, plays an essential role in regulating inflammation via the meditation of NF-κB signaling. In the present study, we attempted to explore the effects of TRUSS on HFD-induced brain injury in the wild type mice (TRUSS+/+) or TRUSS-knockout mice (TRUSS−/-). The results suggested that TRUSS deletion attenuated HFD-induced cognitive impairments in mice. HFD-elicited metabolic disorders were also highly improved by the loss of TRUSS, as evidenced by the reduced serum glucose and insulin levels, as well as the lipid deposition in liver tissues. In addition, HFD-triggered brain injury was markedly alleviated by the TRUSS ablation, as proved by the reduction of GFAP and Iba1 expressions in hippocampus and hypothalamus. Moreover, TRUSS−/- mice exhibited a significant decrease in the expression of pro-inflammatory cytokines, accompanied with the inactivation of IKKα/IκBα/NF-κB pathway. At the same time, HFD-induced dyslipidemia was also alleviated by the loss of TRUSS. The in vitro study verified the protective effects of TRUSS-suppression against HFD-induced central nerve injury and hepatic steatosis by restraining the inflammatory response. In summary, our data indicated that TRUSS participated in metabolic syndrome-induced brain injury and pointed to the repression of TRUSS as a promising strategy for cognitive deficits therapy.

Effects of Solanum torvum fruit water extract on hyperlipidemia and sex hormones in high-fat fed male rats

ObjectiveTo study the effect of water extract of Solanum torvum (S. torvum) on blood lipid and sex hormone levels in high-fat diet (HFD) fed male rats. MethodsMale Wistar rats were maintained on a standard diet or HFD for 10 weeks. During the last 4 weeks, the standard diet groups received distilled water or S. torvum (400 mg/kg) and the HFD groups received distilled water or S. torvum (100, 200 and 400 mg/kg). Body weight, lipid profiles, sex hormone, internal organs weight and liver histopathology were all measured. Moreover, kidney function was evaluated using blood urea nitrogen and creatinine levels, and liver function by the levels of aspartate aminotransferase and alanine aminotransferase. ResultsThe result showed that rats in the HFD control group had increased body weight and hyperlipidemia, but had decreased levels of both testosterone and estradiol. When receiving the S. torvum extract at a dose of 100 mg/kg, treated rats had significantly increased sex hormone levels of both types, and decreased total cholesterol levels, and at a dose of 200 mg/kg, treated rats had significantly decreased levels of triglyceride. Long term administration of the S. torvum did not produce any toxic signs in livers and kidneys. Pathological examinations of livers showed lipid accumulation in the HFD group, but the treatment of S. torvum slightly reduced lipid deposition in liver tissue. ConclusionsS. torvum extract can reverse the level of sex hormones to their normal level and reduce serum cholesterol in HFD-induced obese male rats. Furthermore, the long term oral administration of S. torvum extract is harmless.

Effects of TanshinoneIIA on the modulation of miR‑33a and the SREBP‑2/Pcsk9 signaling pathway in hyperlipidemic rats.

Tanshinone IIA is the active compound isolated from Salvia miltiorrhiza bunge, which is a traditional Chinese medicine known as Danshen. The aim of the present study was to assess the effect of Tanshinone IIA on the regulation of lipid metabolism in the livers of hyperlipidemic rats and the underlying molecular events. An in vivo model of hyperlipidemia was established in rats, with the animals receiving a daily dose of Tanshinone IIA. The serum lipid profiles were analyzed using an automatic biochemical analyzer, and the histopathological alterations and lipid deposition in liver tissue were assessed using hematoxylin and eosin staining, and oil red O staining, respectively. The mRNA expression levels of microRNA (miR)-33a, ATP-binding cassette transporter (ABC)A1, ABCG1, sterol regulatory element-binding protein 2 (SREBP-2), proprotein convertase subtilisin/kexin type 9 (Pcsk9) and low-density lipoprotein receptor (LDL-R) in liver tissues were measured using reverse transcription-quantitative polymerase chain reaction, and the protein expression levels of ABCA1, ABCG1, SREBP-2, Pcsk9, and LDL-R were analyzed using western blotting. Tanshinone IIA reduced lipid deposition and improved histopathology in the rat liver tissue, however, did not alter the lipid profile in rat serum. In addition, Tanshinone IIA treatment suppressed the expression of miR-33a, whereas the protein expression levels of ABCA1, SREBP-2, Pcsk9 in addition to LDL-R mRNA and protein were upregulated. In conclusion, the present study indicated that Tanshinone IIA attenuated lipid deposition in the livers of hyperlipidemic rats and modulated the expression of miR-33a and SREBP-2/Pcsk9 signaling pathway proteins.

Gene Expression Profiling in Hepatic Tissue of two Pig Breeds

Microarray analyses provide information that can be used to enhance the efficiency of livestock production. For example, microarray profiling can potentially identify the biological processes responsible for the phenotypic characteristics of porcine liver. We performed transcriptome profiling to identify differentially expressed genes (DEGs) in liver of pigs from two breeds, the Korean native pigs (KNP) and Yorkshire pigs. We correctly identified expected DEGs using factor analysis for robust microarray summarization (FARMS) and robust multi-array average (RMA) strategies. We identified 366 DEGs in liver (p<0.05, fold-change>2). We also performed functional analyses, including gene ontology and molecular network analyses. In addition, we identified the regulatory relationship between DEGs and their transcription factors using in silico and qRT-PCR analysis. Our findings suggest that DEGs and their transcription factors may have a potential role in adipogenesis and/or lipid deposition in liver tissues of two pig breeds.