Lipid Accumulation In Hepatocytes Research Articles

Sonographic Association Between Fatty Liver and Gall Baldder Stone

Background : Fatty liver (chronic liver disease) was most frequently found associated with gall stones. It arises due to accumulation of lipid in hepatocytes mainly triglyceride. Due to high existence of obesity in the population, the risk of fatty liver and gall stones also increases. In Pakistan the prevalence of fatty liver was 15-20 %. Fatty liver and gall stones could easily be observed on ultrasound. Objective: To evaluate the sonographic association between fatty liver and gall bladder Stone. Study Design : Descriptive Study was conducted Settings: Sanabil health services. Lahore Period: Four months Material & Methods: In our study patients presents with epigastric pain high cholesterol level and previous history of gall stones.While patient with the history of cholecystectomy were excluded. All the data had been composed from Sanabil Health Services Lahore. After informed consent, data was composed through ultrasound machine GE LOGIQ P7 with convex probe (frequency 2.5- 5MHZ) Results: According to results total volume of patient was 220. Now we were comparing between cholelithiasis and grading of fatty liver. Total no of GRADE 1 fatty liver patients were 63 out of 220 in which 13 patients were showing absence of GS while 50 patients showed GS. Total no of GRADE II fatty liver patients were 89 out of 220 in which 36 patients were showing absence of GS while 53 patients showed GS. Total no of GRADE III fatty liver patients were 68 out of 250 in which 20 patients were showing absence of GS while 48 patients showed GS. Total no of 69 out of 220 patients showed absence of GS while 151 patients out of 220 showed with GS. Conclusion: We concluded that the patients who had high cholesterol level, gall stones are associated with fatty liver disease. Moreover fatty liver disease was more common in females than males. Keywords : Nonalcoholic fatty liver, chronic liver disease, Gallbladder, Gall stones, Ultrasound and cholecystokinin. DOI: 10.7176/JHMN/91-09 Publication date: July 31 st 2021

Neddylation inhibition ameliorates steatosis in NAFLD by boosting hepatic fatty acid oxidation via the DEPTOR-mTOR axis

ObjectiveNeddylation is a druggable and reversible ubiquitin-like post-translational modification upregulated in many diseases, including liver fibrosis, hepatocellular carcinoma, and more recently, non-alcoholic fatty liver disease (NAFLD). Herein, we propose to address the effects of neddylation inhibition and the underlying mechanisms in pre-clinical models of NAFLD. MethodsHepatic neddylation measured by immunohistochemical analysis and NEDD8 serum levels measured by ELISA assay were evaluated in NAFLD clinical and pre-clinical samples. The effects of neddylation inhibition by using a pharmacological small inhibitor, MLN4924, or molecular approaches were assessed in isolated mouse hepatocytes and pre-clinical mouse models of diet-induced NAFLD, male adult C57BL/6 mice, and the AlfpCre transgenic mice infected with AAV-DIO-shNedd8. ResultsNeddylation inhibition reduced lipid accumulation in oleic acid-stimulated mouse primary hepatocytes and ameliorated liver steatosis, preventing lipid peroxidation and inflammation in the mouse models of diet-induced NAFLD. Under these conditions, increased Deptor levels and the concomitant repression of mTOR signaling were associated with augmented fatty acid oxidation and reduced lipid content. Moreover, Deptor silencing in isolated mouse hepatocytes abolished the anti-steatotic effects mediated by neddylation inhibition. Finally, serum NEDD8 levels correlated with hepatic neddylation during the disease progression in the clinical and pre-clinical models ConclusionsOverall, the upregulation of Deptor, driven by neddylation inhibition, is proposed as a novel effective target and therapeutic approach to tackle NAFLD.

Monascus ruber fermented Panax ginseng ameliorates lipid metabolism disorders and modulate gut microbiota in rats fed a high-fat diet

Ethnopharmacological relevanceGinseng (Panax ginseng Meyer) is rich in a variety of biologically active ingredients, which shows good effect in the treatment of metabolic diseases. Monascus has lipid-lowering activity and one of its metabolites, lovastatin, is widely used in clinical practice. Aim of the studyThe main purpose of this study was to clarify the effects of fermented Panax ginseng by Monascus ruber (PM) on lipid metabolism and gut microbiota in rats fed a high-fat diet. Materials and methodsSPF Sprague-Dawley rats were randomly divided into 5 groups, the therapeutic effect of PM on HFD-induced obesity, hyperlipidemia, hepatic steatosis, and disordered gut microbiota were determined in rats. ResultsPM could attenuate features of obesity in rats, decrease serum TC, LDL-C and IgA levels, increase excretion of bile acids in feces. Hepatic histopathologic analysis revealed that PM decrease lipid accumulation in hepatocytes. Consistently, mRNA expression levels of cholesterol metabolism-related genes were regulated in the livers of HFD-fed rats administered with PM. In addition, PM could enhance the diversity and relative abundance of gut microbiota, reduce the Firmicutes/Bacteroidetes (F/B) ratio, increase significantly the relative abundance of Prevotella_9, and decrease these of Muribaculaceae. ConclusionsPM could regulate lipid metabolism and the structure of the gut microbiota in the HFD rats. Our findings provide valuable experience for the development of ginseng. PM could be a potentially effective strategy to prevent and treat metabolic diseases and alleviate the gut microbiota disturbance caused by it.

Mitochondria, oxidative stress and nonalcoholic fatty liver disease: A complex relationship.

According to the 'multiple-hit' hypothesis, several factors can act simultaneously in nonalcoholic fatty liver disease (NAFLD) progression. Increased nitro-oxidative (nitroso-oxidative) stress may be considered one of the main contributors involved in the development and risk of NAFLD progression to nonalcoholic steatohepatitis (NASH) characterized by inflammation and fibrosis. Moreover, it has been repeatedly postulated that mitochondrial abnormalities are closely related to the development and progression of liver steatosis and NAFLD pathogenesis. However, it is difficult to determine with certainty whether mitochondrial dysfunction or oxidative stress are primary events or a simple consequence of NAFLD development. On the one hand, increasing lipid accumulation in hepatocytes could cause a wide range of effects from mild to severe mitochondrial damage with a negative impact on cell fate. This can start the cascade of events, including an increase of cellular reactive nitrogen species (RNS) and reactive oxygen species (ROS) production that promotes disease progression from simple steatosis to more severe NAFLD stages. On the other hand, progressing mitochondrial bioenergetic catastrophe and oxidative stress manifestation could be considered accompanying events in the vast spectrum of abnormalities observed during the transition from NAFL to NASH and cirrhosis. This review updates our current understanding of NAFLD pathogenesis and clarifies whether mitochondrial dysfunction and ROS/RNS are culprits or bystanders of NAFLD progression.

Lipid accumulation-induced hepatocyte senescence regulates the activation of hepatic stellate cells through the Nrf2-antioxidant response element pathway

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease globally. Elderly individuals are at a higher risk of developing NAFLD with severe clinical outcomes. Although NAFLD is closely related to liver aging, the role of hepatocyte senescence in the progression of NAFLD, especially in the development of fibrosis, is still unclear. The early stage of NAFLD is mainly characterized by lipid accumulation in hepatocytes, which could lead to severe oxidative stress, causing cellular senescence. In the present study, hepatocytes cultured in the presence of free fatty acids to induce lipid deposition were used as a hepatocyte senescence model in vitro. Senescent hepatocytes significantly increased the activation of co-cultured primary hepatic stellate cells (HSCs) and the expression of pro-fibrosis molecules. Moreover, the antioxidant regulator nuclear factor erythroid 2-related factor 2 (Nrf2) that was upregulated in senescent hepatocytes was found to be related to the activation of co-cultured HSCs. The Nrf2 agonist sulforaphane, which upregulated the transcriptional activity of the Nrf2-antioxidant response element (ARE) pathway, remarkably inhibited hepatocyte senescence and its activation effect on HSCs. However, the liver tissue obtained from non-alcoholic steatohepatitis (NASH) mice with Nrf2 knockdown showed decreased antioxidation and significant liver senescence and fibrosis. In conclusion, this study confirmed that lipid accumulation induces hepatocyte senescence, which leads to HSC activation and development of hepatic fibrosis. Increasing the activity of the Nrf2-ARE antioxidant pathway in senescent hepatocytes elicited the opposite effect, suggesting that targeting Nrf2 may prevent or delay the progression of aging-related liver fibrosis in NASH.

The triterpenoids-enriched extracts from Antrodia cinnamomea mycelia attenuate alcohol-induced chronic liver injury via suppression lipid accumulation in C57BL/6 mice

The major pathologic hallmark of the alcoholic liver disease (ALD) is the representation of chronic alcohol-induced hepatocyte lipid accumulation. This study aims to investigate the hepatoprotective role of triterpenoids-enriched extracts from Antrodia cinnamomea mycelia (ACT) in chronic alcohol-induced liver injury mice, establishing in C57BL/6 mice through gradient alcohol feeding for 24 weeks. In long-term alcohol consumption mice, the significantly lost body weight, increased organ indexes, hepatic alanine aminotransferase and aspartate aminotransferase levels were all remissed after 6-week ACT orally administration, showing its hepatoprotective property. ACT suppressed the triglyceride, total cholesterol and low-density lipoprotein levels, and enhanced high-density lipoprotein levels in serum or/and liver of chronic alcohol damaged mice. Combining with the pathological observations, ACT displayed an anti-steatosis effects to restrain the progress of ALD. Based on proteomic analysis and enzyme-linked immunosorbent assay, ACT had been confirmed to regulate the levels of lipid biogeneration-related factors and depressed the over-accumulation of hepatic reactive oxygen species. According to further data, ACT prevented alcoholic liver injury may be associated with mediating lipid metabolism-related to PGC-1α and NF-κB signaling. In summary, ACT protected the body against chronic alcohol ingest induced liver injury through its regulation lipid on metabolism.

Magnesium Isoglycyrrhizinate Reduces Hepatic Lipotoxicity through Regulating Metabolic Abnormalities.

The excessive accumulation of lipids in hepatocytes induces a type of cytotoxicity called hepatic lipotoxicity, which is a fundamental contributor to liver metabolic diseases (such as NAFLD). Magnesium isoglycyrrhizinate (MGIG), a magnesium salt of the stereoisomer of natural glycyrrhizic acid, is widely used as a safe and effective liver protectant. However, the mechanism by which MGIG protects against NAFLD remains unknown. Based on the significant correlation between NAFLD and the reprogramming of liver metabolism, we aimed to explore the beneficial effects of MGIG from a metabolic viewpoint in this paper. We treated HepaRG cells with palmitic acid (PA, a saturated fatty acid of C16:0) to induce lipotoxicity and then evaluated the antagonistic effect of MGIG on lipotoxicity by investigating the cell survival rate, DNA proliferation rate, organelle damage, and endoplasmic reticulum stress (ERS). Metabolomics, lipidomics, and isotope tracing were used to investigate changes in the metabolite profile, lipid profile, and lipid flux in HepaRG cells under different intervention conditions. The results showed that MGIG can indeed protect hepatocytes against PA-induced cytotoxicity and ERS. In response to the metabolic abnormality of lipotoxicity, MGIG curtailed the metabolic activation of lipids induced by PA. The content of total lipids and saturated lipids containing C16:0 chains increased significantly after PA stimulation and then decreased significantly or even returned to normal levels after MGIG intervention. Lipidomic data show that glycerides and glycerophospholipids were the two most affected lipids. For excessive lipid accumulation in hepatocytes, MGIG can downregulate the expression of the metabolic enzymes (GPATs and DAGTs) involved in triglyceride biosynthesis. In conclusion, MGIG has a positive regulatory effect on the metabolic disorders that occur in hepatocytes under lipotoxicity, and the main mechanisms of this effect are in lipid metabolism, including reducing the total lipid content, reducing lipid saturation, inhibiting glyceride and glycerophospholipid metabolism, and downregulating the expression of metabolic enzymes in lipid synthesis.

A Model of Experimental Steatosis In Vitro: Hepatocyte Cell Culture in Lipid Overload-Conditioned Medium.

Metabolic dysfunction-associated fatty liver disease (MAFLD), previously known as non-alcoholic fatty liver disease (NAFLD), is the most prevalent liver disease worldwide due to its relationship with obesity, diabetes type 2, and dyslipidemia. Hepatic steatosis, the accumulation of lipid droplets in the liver parenchyma, is a key feature of the disease preceding the inflammation observed in steatohepatitis, fibrosis, and end-stage liver disease. Lipid accumulation in hepatocytes might interfere with proper metabolism of xenobiotics and endogenous molecules, as well as to induce cellular processes leading to the advance of the disease. Although the experimental study of steatosis can be performed in vivo, in vitro approaches to the study of steatosis are complementary tools with different advantages. Hepatocyte culture in lipid overload-conditioned medium is an excellent reproducible option for the study of hepatic steatosis allowing the identification of cellular processes related to lipid accumulation, such as oxidative and reticular stresses, autophagia, proliferation, cell death, etcetera, as well as other testing including drug effectiveness, and toxicological testing, among many other possible applications. Here, it was aimed to describe the methodology of hepatocyte cell culture in lipid overload-conditioned medium. HepG2 cells were cultured in RMPI 1640 medium conditioned with sodium palmitate and sodium oleate. Importantly, the ratio of these two lipids is crucial to favor lipid droplet accumulation, while maintaining cell proliferation and a moderate mortality rate, as occurs in the liver during the disease. The methodology, from the preparation of the lipid solution stocks, mixture, addition to the medium, and hepatocyte culture is shown. With this approach, it is possible to identify lipid droplets in the hepatocytes that are readily observable by Oil-red O staining, as well as curves of proliferation/mortality rates.

Hepatic GH Receptor Signaling Directly Suppresses Hepatic Steatosis and De Novo Lipogenesis, Independent of Changes in Plasma IGF1 and Insulin

A reduction in GH, as well as IGF1, is associated with non-alcoholic fatty liver disease (NAFLD). However, the relative contribution of changes in circulating GH and IGF1, to hepatic triglyceride accumulation (steatosis), remains to be clearly defined. To study the direct actions of GH on hepatocyte metabolism, we have utilized a mouse model of adult-onset, hepatocyte-specific, GHR knockdown (aHepGHRkd; 10–12 week-old, GHRfl/fl male mice, treated with AAV8-TBGp-Cre). In this and previous reports, we have observed that aHepGHRkd male mice rapidly develop steatosis (after 7 days) associated with enhanced de novo lipogenesis (DNL; measured by deuterated H2O labeling, 10h after 0800h food removal), and low ketone levels, suggestive of reduced hepatic β-oxidation. Of note, aHepGHRkd also reduces plasma IGF1 levels to >80% of GHR-intact controls (GHRfl/fl mice treated with AAV8-TBGp-Null), leading to a rise in GH, due to loss of IGF1 negative feedback to the pituitary/hypothalamus. This reciprocal shift in IGF1/GH is associated with an increase in insulin levels. Therefore, it is possible that the steatosis that develops in aHepGHRkd mice is the consequence of systemic insulin resistance supplying excess substrates (glucose and NEFA) for hepatic lipogenesis. However, inconsistent with this theory is the fact that glucose and NEFA levels are not altered after aHepGHRkd. To tease out the indirect (perhaps driven by high insulin levels) vs. direct effects of GH on hepatocyte lipid accumulation, male aHepGHRkd mice were injected with a vector expressing rat IGF1 (AAV8-TBGp-rIGF1). Reconstitution of hepatocyte IGF1 in aHepGHRkd mice, raised plasma IGF1 and normalized GH, insulin and ketone levels, but hepatic steatosis and DNL remained greater than that of GHR-intact controls, indicating GH directly suppresses hepatic fat accumulation. RNAseq analysis of livers from aHepGHRkd mice showed expression of genes related to carbohydrate metabolism (Gck, Khk) and fatty acid synthesis (Fasn, Srebf1, Usf1), processing (Scd1) and uptake (Cd36) were increased, while genes related to gluconeogenesis (Pck1, Fbp1, G6pc) were reduced. Remarkably, IGF1 reconstitution had no major impact on the hepatic transcriptome of aHepGHRkd mice, with the exception of reducing the expression of Srebf1, consistent with the reduction in circulating insulin levels. Interestingly, carbohydrate-responsive element-binding protein (CHREBP) levels, but not mRNA levels, were greater in aHepGHRkd mice with or without IGF1 reconstitution, consistent with upregulation of CHREBP target genes (Khk and Fasn among others). Taken together, these results suggest GH directly regulates steatosis, at least in part, by suppressing carbohydrate-driven DNL, where additional studies are underway to test this hypothesis.

Inhibition of Elongation Factor 1A1 Activity Decreases Lipid Droplet Accumulation

Non-alcoholic fatty liver disease (NAFLD) is characterized by hepatocyte lipid accumulation, which can cause hepatocyte injury through lipotoxicity. Eukaryotic elongation factor 1A1 (EEF1A1), which is a component of the protein synthetic machinery and regulates actin cytoskeleton turnover, is induced in human hepatocyte-like HepG2 cells undergoing lipotoxicity, in association with ER stress. Moreover, EEF1A1 has been identified in the lipid droplet (LD) proteome in various cell and tissue types, suggesting that it may have a role in LD biology. Partial inhibition of EEF1A1 peptide elongation activity with the marine compound didemnin B (DB) decreases lipotoxic HepG2 cell death. However, the effects of EEF1A1 inhibition on cellular lipid accumulation are unclear. Based on the potential association of EEF1A1 with LDs, and its apparent roles in responding to ER stress and in regulating cytoskeleton dynamics, we hypothesized that inhibition of EEF1A1 with DB would alter hepatocyte LD accumulation. Male 129S6 mice were fed a western diet for 26 weeks to induce NAFLD, followed by intervention with DB (50 μg/kg, i.p.) once every 3 days for 14 days. Treatment with DB decreased liver lipid accumulation, as determined by biochemical and histological analyses, and upregulated expression of genes involved in fatty acid oxidation (Cpt1a, Fgf21). Assessments of LD size in mouse liver revealed a significant decrease in median size upon treatment with DB, suggesting that DB promotes the formation of smaller LDs. To explore whether this effect was conserved in human hepatocyte-like cells, HepG2 cells were treated for 6 h with DB (80 nM) under lipotoxic conditions (1 mM palmitate plus oleate) and LDs were visualized by confocal microscopy. Cells exposed to lipotoxic conditions exhibited increased LD area, and treatment with DB appeared to decrease the formation of large LDs (-63%, p=0.11). This occurred alongside upregulation of CPT1A mRNA, which was consistent with the upregulation of genes involved in fatty acid oxidation observed in mouse liver. Finally, a Chinese hamster ovary cell line that harbors a mutation leading to reduced EEF1A1 expression accumulated less triglyceride under high fatty acid conditions compared to wild-type cells. Together, these findings suggest that that disruption of EEF1A1 activity may diminish LD accumulation and channel excess fatty acids toward oxidation, which could have implications for the treatment of NAFLD.

Lampaya Medicinalis Phil. decreases lipid-induced triglyceride accumulation and proinflammatory markers in human hepatocytes and fat body of Drosophila melanogaster.

Excess hepatic triglyceride (TG) accumulation (steatosis) commonly observed in obesity, may lead to non-alcoholic fatty liver disease (NAFLD). Altered regulation of intracellular lipid droplets (LD) and TG metabolism, as well as activation of JNK-mediated proinflammatory pathways may trigger liver steatosis-related disorders. Drosophila melanogaster is an animal model used for studying obesity and its associated disorders. In Drosophila, lipids and glycogen are stored in the fat body (FB), which resembles mammalian adipose tissue and liver. Dietary oversupply leads to obesity-related disorders, which are characterized by FB dysfunction. Infusions of Lampaya medicinalis Phil. (Verbenaceae) are used in folk medicine of Chile to counteract inflammatory diseases. Hydroethanolic extract of lampaya (HEL) contains considerable amounts of flavonoids that may explain its anti-inflammatory effect. We studied whether HEL affects palmitic acid (PA, C16:0) and oleic acid (OA; C18:1)-induced TG accumulation and proinflammatory marker content in HepG2 hepatocytes as well as impaired lipid storage and proinflammatory molecule expression in Drosophila melanogaster fed a high-fat diet (HFD). In HepG2 hepatocytes, exposure to OA/PA elevated TG content, FABP4, ATGL and DGAT2 expression, and the JNK proinflammatory pathway, as well as TNF-α and IL-6 production, while diminished FAS expression. These effects were prevented by HEL co-treatment. In Drosophila larvae fed a HFD, HEL prevented TG accumulation and downregulated proinflammatory JNK pathway activation. HEL effect counteracting OA/PA- and HFD-induced lipid accumulation and proinflammatory marker expression in HepG2 hepatocytes and Drosophila larvae may represent a preventive approach against hepatic steatosis and inflammation, associated to obesity and NAFLD.

Upregulated SOCC and IP3R calcium channels and subsequent elevated cytoplasmic calcium signaling promote nonalcoholic fatty liver disease by inhibiting autophagy.

Nonalcoholic fatty liver disease (NAFLD) is related to elevated cytoplasmic calcium signaling in hepatocytes, which may be mediated by store-operated calcium channel (SOCC) and inositol triphosphate receptor (IP3R). However, the regulatory effect of calcium signaling on lipid accumulation and degeneration in hepatocytes and the underlying molecular mechanism remain unknown. Autophagy inhibition promotes lipid accumulation and steatosis in hepatocytes. However, the association between elevated calcium signaling and autophagy inhibition in hepatocytes and its effect on hepatocyte fatty lesions remain unclear. Here, we established a mouse hepatocyte fatty gradient model using oleic acid. SOCC and IP3R channel opening and cytoplasmic calcium levels gradually increased with the hepatocyte pimelosis degree, whereas autophagy gradually decreased. We also established an optimal oleic acid (OOA) hepatocyte model, observing significantly increased SOCC and IP3R channel opening and calcium influx alongside significantly decreased autophagy and aggravated cellular fatty lesion. Calcium channel blockers (CCBs) and calcium channel gene silencing reagents (CCGSRs), respectively, reversed these effects, indicating that elevated cytoplasmic calcium signaling promotes NAFLD occurrence and the development by inhibiting hepatocyte autophagy. In the OOA model, upregulated extracellular regulated protein kinases 1/2 (ERK1/2), which can be regulated by SOCC and IP3R proteins transient receptor potential canonical 1 (TRPC1)/IP3R with elevated cytoplasmic calcium signaling, over-inhibited forkhead/winged helix O (FOXO) signaling and over-activated mammalian target of rapamycin complex 1 (mTORC1) signaling. Over-inhibited FOXO signaling significantly downregulated autophagy-related gene 12, which inhibits autophagosome maturation, while over-activated mTORC1 signaling over-inactivated Unc-51 like autophagy activating kinase 1, which inhibits preautophagosome formation. CCBs and CCGSRs recovered autophagy by significantly downregulating ERK1/2 to block abnormal changes in FOXO and mTORC1 signaling. Our findings indicate that upregulated SOCC and IP3R channels and subsequent elevated cytoplasmic calcium signaling in hepatocyte fatty lesions inhibits hepatocyte autophagy through (TRPC1/IP3R)/ERK/(FOXO/mTORC1) signaling pathways, causes lipid accumulation and degeneration in hepatocytes, and promotes NAFLD occurrence and development.

Collagen β(1-O) galactosyltransferase 2 deficiency contributes to lipodystrophy and aggravates NAFLD related to HMW adiponectin in mice

AimOur previous results showed that Colgalt1 knock-out resulted in fetal death on day E11.5, and collagen secretion was retarded. This study aimed to elucidate the role of Collagen β(1-O) galactosyltransferase 2 (Colgalt2) in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). MethodsColgalt2−/− mice were fed a high-fat diet (HFD) or methionine-and choline-deficient diet (MCD). Nanopore long-read RNA-Seq analysis of liver tissues was used to profile genomic variation. In vitro, hepatocyte steatosis and differentiation of primary pre-adipocytes were induced. ResultsColgalt2−/− mice exhibited lipodystrophy, increased body weight, and hepatic lipid accumulation at 6 weeks of age. Colgalt2 deficiency aggravated hepatic steatosis in mice fed an HFD or a standard laboratory chow diet. Colgalt2 deficiency promotes steatohepatitis in MCD-fed mice. In HFD mice, Colgalt2 deficiency caused lipodystrophy and decreased plasma HMW, total adiponectin, and leptin levels. Colgalt2 deficiency also reduced circulating HMW/Total adiponectin in mice fed a HFD diet without differences of adiponectin mRNA and protein level in WT and Colgalt2−/− mice. The nanopore long-read RNA-Seq analysis results revealed transcriptional changes in the adiponectin receptor downstream signaling pathway and lipogenic genes, including the AMPK signaling pathway, adipocytokine signaling pathway, and lipid metabolism (Cidea, Cidec, CD36, and PPARγ). Colgalt2 deficiency did not promote lipid accumulation in OA-induced HepG2 cells or primary hepatocytes. However, Colgalt2 deficiency inhibited adipogenesis and reduced PPARγ, adipogenesis-related transcription factors, and expression during adipocyte differentiation. ConclusionsIn mice, Colgalt2 deficiency contributes to lipodystrophy and promotes NAFLD related to HMW adiponectin. These results suggest that Colgalt2 could be a novel and promising therapeutic strategy for the treatment of NAFLD.

Relationship between NAFLD and Periodontal Disease from the View of Clinical and Basic Research, and Immunological Response.

Periodontal disease is an inflammatory disease caused by pathogenic oral microorganisms that leads to the destruction of alveolar bone and connective tissues around the teeth. Although many studies have shown that periodontal disease is a risk factor for systemic diseases, such as type 2 diabetes and cardiovascular diseases, the relationship between nonalcoholic fatty liver disease (NAFLD) and periodontal disease has not yet been clarified. Thus, the purpose of this review was to reveal the relationship between NAFLD and periodontal disease based on epidemiological studies, basic research, and immunology. Many cross-sectional and prospective epidemiological studies have indicated that periodontal disease is a risk factor for NAFLD. An in vivo animal model revealed that infection with periodontopathic bacteria accelerates the progression of NAFLD accompanied by enhanced steatosis. Moreover, the detection of periodontopathic bacteria in the liver may demonstrate that the bacteria have a direct impact on NAFLD. Furthermore, Porphyromonas gingivalis lipopolysaccharide induces inflammation and accumulation of intracellular lipids in hepatocytes. Th17 may be a key molecule for explaining the relationship between periodontal disease and NAFLD. In this review, we attempted to establish that oral health is essential for systemic health, especially in patients with NAFLD.

O-1602 Promotes Hepatic Steatosis through GPR55 and PI3 Kinase/Akt/SREBP-1c Signaling in Mice.

Non-alcoholic fatty liver disease is recognized as the leading cause of chronic liver disease. Overnutrition and obesity are associated with hepatic steatosis. G protein-coupled receptor 55 (GPR55) has not been extensively studied in hepatic steatosis, although its endogenous ligands have been implicated in liver disease progression. Therefore, the functions of GPR55 were investigated in Hep3B human hepatoma cells and mice fed high-fat diets. O-1602, the most potent agonist of GPR55, induced lipid accumulation in hepatocytes, which was reversed by treatment with CID16020046, an antagonist of GPR55. O-1602 also induced intracellular calcium rise in Hep3B cells in a GPR55-independent manner. O-1602-induced lipid accumulation was dependent on the PI3 kinase/Akt/SREBP-1c signaling cascade. Furthermore, we found increased levels of lysophosphatidylinositol species of 16:0, 18:0, 18:1, 18:2, 20:1, and 20:2 in the livers of mice fed a high-fat diet for 4 weeks. One-week treatment with CID16020046 suppressed high-fat diet-induced lipid accumulation and O-1602-induced increase of serum triglyceride levels in vivo. Therefore, the present data suggest the pro-steatotic function of GPR55 signaling in hepatocytes and provide a potential therapeutic target for non-alcoholic fatty liver disease.

STE20-Type Protein Kinase MST4 Controls NAFLD Progression by Regulating Lipid Droplet Dynamics and Metabolic Stress in Hepatocytes.

Nonalcoholic fatty liver disease (NAFLD) has emerged as a leading cause of chronic liver disease worldwide, primarily because of the massive global increase in obesity. Despite intense research efforts in this field, the factors that govern the initiation and subsequent progression of NAFLD are poorly understood, which hampers the development of diagnostic tools and effective therapies in this area of high unmet medical need. Here we describe a regulator in molecular pathogenesis of NAFLD: STE20‐type protein kinase MST4. We found that MST4 expression in human liver biopsies was positively correlated with the key features of NAFLD (i.e., hepatic steatosis, lobular inflammation, and hepatocellular ballooning). Furthermore, the silencing of MST4 attenuated lipid accumulation in human hepatocytes by stimulating β‐oxidation and triacylglycerol secretion, while inhibiting fatty acid influx and lipid synthesis. Conversely, overexpression of MST4 in human hepatocytes exacerbated fat deposition by suppressing mitochondrial fatty acid oxidation and triacylglycerol efflux, while enhancing lipogenesis. In parallel to these reciprocal alterations in lipid storage, we detected substantially decreased or aggravated oxidative/endoplasmic reticulum stress in human hepatocytes with reduced or increased MST4 levels, respectively. Interestingly, MST4 protein was predominantly associated with intracellular lipid droplets in both human and rodent hepatocytes. Conclusion: Together, our results suggest that hepatic lipid droplet–decorating protein MST4 is a critical regulatory node governing susceptibility to NAFLD and warrant future investigations to address the therapeutic potential of MST4 antagonism as a strategy to prevent or mitigate the development and aggravation of this disease.

Bioengineered Multicellular Liver Microtissues for Modeling Advanced Hepatic Fibrosis Driven Through Non-Alcoholic Fatty Liver Disease.

Despite considerable efforts in modeling liver disease in vitro, it remains difficult to recapitulate the pathogenesis of the advanced phases of non-alcoholic fatty liver disease (NAFLD) with inflammation and fibrosis. Here, a liver-on-a-chip platform with bioengineered multicellular liver microtissues is developed, composed of four major types of liver cells (hepatocytes, endothelial cells, Kupffer cells, and stellate cells) to implement a human hepatic fibrosis model driven by NAFLD: i) lipid accumulation in hepatocytes (steatosis), ii) neovascularization by endothelial cells, iii) inflammation by activated Kupffer cells (steatohepatitis), and iv) extracellular matrix deposition by activated stellate cells (fibrosis). In this model, the presence of stellate cells in the liver-on-a-chip model with fat supplementation showed elevated inflammatory responses and fibrosis marker up-regulation. Compared to transforming growth factor-beta-induced hepatic fibrosis models, this model includes the native pathological and chronological steps of NAFLD which shows i) higher fibrotic phenotypes, ii) increased expression of fibrosis markers, and iii) efficient drug transport and metabolism. Taken together, the proposed platform will enable a better understanding of the mechanisms underlying fibrosis progression in NAFLD as well as the identification of new drugs for the different stages of NAFLD.

34646 DEFICIENCY OF NOVEL ADIPOKINE TETRANECTIN INCREASES OBESITY AND INSULIN RESISTANCE IN FEMALES

ABSTRACT IMPACT: Novel adipokines like tetranectin help explain why some people progress from obesity to diseases like diabetes, atherosclerosis, and dislipidemia OBJECTIVES/GOALS: Obesity has an established association with diabetes, dyslipidemia, and atherosclerosis. Preventing progression from obesity to insulin resistance requires understanding of the regulatory mechanisms involved in the loss of insulin sensitivity. Adipose tissue is well known to function as an endocrine organ that produces many kinds of adipokines. METHODS/STUDY POPULATION: Blood sample analysis from human patients and mice was used to determine associations between tetranectin and obesity. Samples were tested with a monoclonal anti-tetranectin antibody for detection with western blot. A tetranectin mutant knock out mouse line was compared to wild type littermates on high fat diet for 4 months. Insulin tolerance tests and glucose tolerance were used to determine progression to insulin resistance and glucose intolerance. Histological analysis of metabolic tissue was used to demonstrate adipocyte hypertrophy and liver steatosis. RESULTS/ANTICIPATED RESULTS: In the current study, we report the identification and initial characterization of a novel adipokine tetranectin. Tetranectin, which is coded by the C-type lectin domain family 3 member B (CLEC3B) gene, is ubiquitously expressed in various mouse tissues, whereas it is highly enriched in white adipose tissue. We found that the serum level of tetranectin was much higher in both obese and diabetic patients. Knocking out the tetranectin gene in mice protected against glucose intolerance in males but reduced insulin and glucose tolerance in females, without effects on food intake and body weight for either sex. Mechanistically, tetranectin targets liver tissues and its deficiency increases lipid accumulation in hepatocytes in females. DISCUSSION/SIGNIFICANCE OF FINDINGS: We have identified a novel adipokine which mediates a different metabolic crosstalk among tissues to maintain systemic glucose and lipid metabolism in different genders. Further investigation of tetranectin’s function could yield a new target for precise therapeutic treatment for obesity and its associated metabolic diseases in different genders

Stress can attenuate hepatic lipid accumulation via elevation of hepatic β-muricholic acid levels in mice with nonalcoholic steatohepatitis

AbstractStress can affect our body and is known to lead to some diseases. However, the influence on the development of nonalcohol fatty liver disease (NAFLD) remains unknown. This study demonstrated that chronic restraint stress attenuated hepatic lipid accumulation via elevation of hepatic β-muricholic acid (βMCA) levels in the development of nonalcoholic steatohepatitis (NASH) in mice. Serum cortisol and corticosterone levels, i.e., human and rodent stress markers, were correlated with serum bile acid levels in patients with NAFLD and methionine- and choline-deficient (MCD) diet-induced mice, respectively, suggesting that stress is related to bile acid (BA) homeostasis in NASH. In the mouse model, hepatic βMCA and cholic acid (CA) levels were increased after the stress challenge. Considering that a short stress enhanced hepatic CYP7A1 protein levels in normal mice and corticosterone increased CYP7A1 protein levels in primary mouse hepatocytes, the enhanced Cyp7a1 expression was postulated to be involved in the chronic stress-increased hepatic βMCA level. Interestingly, chronic stress decreased hepatic lipid levels in MCD-induced NASH mice. Furthermore, βMCA suppressed lipid accumulation in mouse primary hepatocytes exposed to palmitic acid/oleic acid, but CA did not. In addition, Cyp7a1 expression seemed to be related to lipid accumulation in hepatocytes. In conclusion, chronic stress can change hepatic lipid accumulation in NASH mice, disrupting BA homeostasis via induction of hepatic Cyp7a1 expression. This study discovered a new βMCA action in the liver, indicating the possibility that βMCA is available for NAFLD therapy.Chronic stress can change hepatic lipid accumulation via elevation of hepatic β-muricholic acid levels in nonalcoholic steatohepatitis mice, disrupting bile acid homeostasis by induction of hepatic Cyp7a1 expression. This study describes a new role βMCA in the liver, indicating its potential usefulness for nonalcohol fatty liver disease therapy.

Role of Chitinase 3-Like 1 Protein in the Pathogenesis of Hepatic Insulin Resistance in Nonalcoholic Fatty Liver Disease.

A recently discovered human glycoprotein, chitinase 3-like 1 (Chi3L1), may play a role in inflammation, tissue remodeling, and visceral fat accumulation. We hypothesize that Chi3L1 gene expression is important in the development of hepatic insulin resistance characterized by the generation of pAKT, pGSK, and pERK in wild type and Chi3L1 knockout (KO) murine liver following insulin stimulation. The Chi3L1 gene and protein expression was evaluated by Real Time PCR and ELISA; lipid accumulation in hepatocytes was also assessed. To alter Chi3L1 function, three different anti-Chi3L1 monoclonal antibodies (mAbs) were administered in vivo and effects on the insulin signaling cascade and hepatic lipid deposition were determined. Transmission of the hepatic insulin signal was substantially improved following KO of the CHi3L1 gene and there was reduced lipid deposition produced by a HFD. The HFD-fed mice exhibited increased Chi3L1 expression in the liver and there was impaired insulin signal transduction. All three anti-Chi3L1 mAbs partially restored hepatic insulin sensitivity which was associated with reduced lipid accumulation in hepatocytes as well. A KO of the Chi3L1 gene reduced lipid accumulation and improved insulin signaling. Therefore, Chi3L1 gene upregulation may be an important factor in the generation of NAFLD/NASH phenotype.