Accumulation Of Fat Droplets Research Articles

A nanodrug system overexpressed circRNA_0001805 alleviates nonalcoholic fatty liver disease via miR-106a-5p/miR-320a and ABCA1/CPT1 axis

Our study aimed to explore the function of circRNA_0001805 in the pathogenesis of NAFLD and the underlying mechanism. A nanodrug system (GA-RM/GZ/PL) was constructed to overexpress circRNA_0001805 specifically in hepatocytes for the treatment of NAFLD. Fat droplet accumulation in cultured cells and mouse hepatic tissues was detected using Oil Red O or H&E staining. The relative expression of circRNAs, genes associated with lipogenesis was quantified by qRT-PCR. Interactions between circRNA_0001805 and miR-106a-5p/miR-320a, between miR-106a-5p/miR-320a and ABCA1/CPT1 were confirmed by dual-luciferase reporter assay. A novel metalorganic framework nanocarrier (GZ) was prepared from glycyrrhizic acid and zinc ions (Zn2+), and this nanocarrier was loaded with the circRNA_0001805 plasmid to construct a nanocore (GZ/PL). Then, this GZ/PL was coated with a galactose-modified RBC membrane (GA-RM) to generate GA-RM/GZ/PL. CircRNA_0001805 expression was downregulated in FFA-challenged primary hepatocytes, HFD-fed mice and NAFLD patients. Overexpressed circRNA_0001805 attenuated NAFLD development by suppressing lipid metabolism disorder and inflammation. CircRNA_0001805 targeted miR-106a-5p/miR-320a, which served as an upstream inhibitor of ABCA1/CPT1 and collaboratively regulated NAFLD progression. GA-RM/GZ/PL targeted hepatocytes, overexpressed circRNA_0001805, released glycyrrhizic acid to reduce the accumulation of lipids in the liver and played a synergistic role against NAFLD-induced lipid metabolism disorder.Graphical

Mechanism of Huo-Xue-Qu-Yu Formula in Treating Nonalcoholic Hepatic Steatosis by Regulating Lipid Metabolism and Oxidative Stress in Rats.

Huo-Xue-Qu-Yu formula (HXQYF) is a prescription consisting of Ginkgo biloba leaf and Paeonia lactiflora Pall. for treating hyperlipidemia and NAFLD in China. Here, we investigated the hepatic and renal function, oxidative stress and lipid metabolism, and potential mechanisms of HXQYF on nonalcoholic fatty liver disease (NAFLD) rat models. NAFLD rat models were induced with high-fat diet (HFD) and 10% fructose water for 18 weeks and orally administered with or without HXQYF simultaneously. The results showed that HXQYF (22.5, 45, 90 mg/kg) significantly improved blood lipid levels via reducing serum TC, TG, LDL-C, and APOB values and elevating HDL-C and APOA1 levels in NAFLD rats. The higher levels of ALT, AST, CR, and BUN in serum induced by HFD were reduced by HXQYF. HE staining showed that HXQYF (90 mg/kg) reduced the accumulation of fat droplets and alleviated inflammatory response in liver cells. Three doses of HXQYF exhibited notable antioxidant effects by elevating SOD, GSH, and CAT activities and decreasing MDA and OH-1 levels in the liver. Furthermore, abnormal lipid metabolism caused by HFD was alleviated by HXQYF, which was associated with the upregulation of PPAR-α, AdipoR2, and CPT1 mRNAs as well as the downregulation of CYP2E1 and SREBP-1c mRNAs in liver tissue. In conclusion, our work verified that HXQYF could reduce the degree of hepatic steatosis, suppress oxidative stress, and attenuate lipid metabolism, thus preventing NAFLD.

Hydro alcoholic green tea extract effect on high fat diet treated NMRI mice and 3T3L1 cells.

In order to counteract the obesity has epidemics, since current anti-obesity drugs effects remain limited, there is a need to provide new options. As a project aiming to assess potential anti obesity natural compounds, the effects of consumption of a minimal dose of green tea hydro alcoholic extract (GT) on adipocyte differentiation of 3T3L1 cell line were investigated. Obesity was induced in female NMRI mice (which are less used overall) by the use of a high fat diet. Mice were divided into four groups of control (C), treated control (TC), obese (O) and treated obese (TO). TC and TO groups received 8mg/Kg/day of GT for 8 weeks, and weighted weekly, after what biochemical and histological parameters were measured. GT was used at doses of 100,150 and 200µg/ml on 3T3L1, and staining with Oil-red-O was done for estimation of fat droplet accumulation. Body weight was found to be affected significantly by GT. Blood glucose levels did not show significant changes between groups, while triglycerides levels of the O group was significantly higher than the C group, but the TO group showed no significant difference with the C group upon GT treatment. Liver and visceral fat tissues showed more normalized tissue and less fat accumulation in the TO group. TO and TC groups showed an ameliorated morphologic state of liver tissues. GT was also able to decrease fat droplet formation in a dose-dependent manner. Adding a minimal amount of GT to the daily consumption may have preventive effects on fat accumulation in healthy subjects, while in obese cases, GT shows significant therapeutic effect.

Curcumin improves adipocytes browning and mitochondrial function in 3T3-L1 cells and obese rodent model.

Accumulating evidence suggests that mitochondrial dysfunction and adipocyte differentiation promote lipid accumulation in the development of obesity and diabetes. Curcumin is an active ingredient extracted from Curcuma longa that has been shown to exhibit antioxidant and anti-inflammatory potency in metabolic disorders. However, the underlying mechanisms of curcumin in adipocytes remain largely unexplored. We studied the effects of curcumin on adipogenic differentiation and mitochondrial oxygen consumption and analysed the possible mechanisms. 3T3-L1 preadipocytes were used to assess the effect of curcumin on differentiation of adipocytes. The Mito Stress Test measured by Seahorse XF Analyzer was applied to investigate the effect of curcumin on mitochondrial oxygen consumption in 3T3-L1 adipocytes. The effect of curcumin on the morphology of both white and brown adipose tissue (WAT and BAT) was evaluated in a high-fat diet-induced obese mice model. We found that curcumin dose-dependently (10, 20 and 35 µM) induced adipogenic differentiation and the intracellular fat droplet accumulation. Additionally, 10 µM curcumin remarkably enhanced mature adipocyte mitochondrial respiratory function, specifically, accelerating basic mitochondrial respiration, ATP production and uncoupling capacity via the regulation of peroxisome proliferator-activated receptor γ (PPARγ) (p < 0.01). Curcumin administration also attenuated the morphological changes in adipose tissues in high-fat diet-induced obese mice. Moreover, curcumin markedly increased the mRNA and protein expressions of mitochondrial uncoupling protein 1 (UCP1), PPARγ, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and PR domain protein 16 (PRDM16) in vivo and in vitro. Collectively, the results demonstrate that curcumin promotes the adipogenic differentiation of preadipocytes and mitochondrial oxygen consumption in 3T3-L1 mature adipocytes by regulating UCP1, PRDM16, PPARγ and PGC-1α expression.

Study of ultrasonic scattering mechanisms in nonalcoholic fatty liver disease using liver histopathological slides

Quantitative ultrasound (QUS) techniques are emerging to be useful for assessing nonalcoholic fatty liver disease (NAFLD), the accumulation of fat droplets in the liver without alcohol intake. Several QUS parameters, such as the backscatter coefficient (BSC), are known to be correlated with liver fat content. However, the underlining ultrasonic scattering mechanisms are not fully understood. Understanding these mechanisms may yield better QUS models for improved diagnostics. This study's purpose is to test the following hypothesized mechanism: hepatocyte nuclei are acoustic scattering sites and the accumulation of fat droplets changes the spatial distribution of hepatocyte nuclei, leading to the change of the structure function (SF), a component of the BSC. Hematoxylin and eosin-stained liver histopathological slides from 48 participants were digitized. Hepatocyte nuclei and fat droplets were automatically recognized. For each participant, the SF versus frequency was calculated from the nuclear distribution. The fat fraction (FF) was determined by the fractional surface area of fat droplets. The SF was positively correlated with the FF (Pearson's r ∼ 0.4, p &amp;lt; 10-4) between frequencies 1 and 30 MHz, supporting the hypothesized mechanism. Other potential mechanisms, such as the additional scattering caused by fat droplets, will also be discussed. [Work supported by R01DK106419 and R01CA226528-01A1.]

Noninvasive 40-Hz Light Flicker Rescues Circadian Behavior and Abnormal Lipid Metabolism Induced by Acute Ethanol Exposure via Improving SIRT1 and the Circadian Clock in the Liver-Brain Axis.

Sirtuin 1 (SIRT1) is a protein deacetylase with important cellular functions, as it regulates numerous processes, including the circadian rhythm in peripheral tissues. Efforts are ongoing to reveal how Sirt1 can be used to treat diseases, such as alcoholic liver disease (ALD), Alzheimer's disease, and liver fibrosis. We have recently shown that noninvasive exposure to 40-Hz light flicker activates hypothalamic SIRT1 gene expression, thereby regulating the central circadian clock. This study investigated the effects of 40-Hz light flicker in a mouse model of ALD. RNA sequencing (RNA-seq) analysis was performed to explore the potential pathways affected by 40-Hz light flicker. We found that 40-Hz light flicker significantly decreased the acute ethanol-induced increases in serum alanine aminotransferase (ALT) and serum triglyceride (TG) levels and reduced fat-droplet accumulation in mouse livers. Additionally, 40-Hz light flicker significantly suppressed ethanol-induced increases in sterol regulatory element binding protein 1 (SREBP-1) and fatty acid synthase (Fasn) levels. Furthermore, the ethanol induced significant decreases in both Sirt1 levels and phosphorylation of adenosine monophosphate-activated protein kinase subunit (AMPKα), compared with those in the control group. Strikingly, pretreatment with 40-Hz light flicker ameliorated such ethanol-induced decreases in SIRT1 levels and AMPKα phosphorylation. In addition, ethanol-induced increases in levels of brain and muscle arnt-like protein-1 (BMAL1), circadian locomotor output cycles kaput (CLOCK), and period 2 (PER2) were reversed by 40-Hz light flicker. RNA-seq analysis revealed significant differences in expression of genes related to the AMPK signalling. Moreover, ethanol consumption altered mRNA levels of Sirt1 and circadian genes in the suprachiasmatic nucleus (SCN), indicating that ethanol influenced central pacemaker genes; however, 40-Hz light flicker reversed these ethanol-induced changes. Taken together, our findings demonstrate that 40-Hz light flicker rapidly influence the SCN and exhibits inhibitory properties on hepatic lipogenesis, indicating that 40-Hz light flicker has therapeutic potential for preventing alcoholic liver steatosis.

3-Mercaptopyruvate sulfurtransferase disruption in dermal fibroblasts facilitates adipogenic trans-differentiation

Transitioning from a differentiated state to a higher-order of plasticity, by partial rather than full reactivation of pluripotency genes, might be a better approach in regenerative medicine. Hydrogen sulfide plays a crucial role in the maintenance and differentiation of mesenchymal stem cells (MSC) that have the potential to differentiate to a diverse group of mesenchymally derived cells. It was shown that these cells show a heavy reliance on cystathionine-β-synthase (CBS)-derived hydrogen sulfide (H2S) during differentiation. We have found that expression and activity of 3-mercaptopyruvate sulfurtransferase (MPST), one of three enzymes that hat regulates H2S biosynthesis, is significantly lower in MSC as compared with lineage-restricted dermal fibroblasts. Here, we tested the hypothesis that suppression of MPST in dermal fibroblasts might induce plasticity-related changes and broaden the transdifferentiation potency. Inactivation of MPST with phenylpyruvate (PP) or by siRNA silencing led to diminished H2S production associated with increased production of reactive oxygen species (ROS) and lactic acid. Accumulation of α-ketoglutarate (α-KG), a key metabolite required for the expression of ten-eleven translocation hydroxylase (TET), was associated with stimulated transcription of pluripotency related genes including OCT4, KLF4, SOX2, and NANOG. Suppression of TET1 gene and inhibition of glycolysis with glucose analog, 2-desoxy-d-glucose, or hexokinase II inhibitor significantly reduced expression of pluripotency genes following MPST inactivation or knockdown. MPST disruption promoted the conversion of fibroblasts into adipocytes as evidenced by a significant increase in expression of adipocyte-specific genes, PPARγ, and UCP1, and intracellular accumulation of oil Red-O positive fat droplets. Inhibition of glycolysis inhibited these changes. Under induced differentiation conditions, fibroblasts with disrupted MPST show the potency to differentiate to white adipogenic lineage. Thus, MPST inactivation or silencing enhances the plasticity of dermal fibroblasts in a TET1 and glycolysis dependent manner and promotes adipogenic transdifferentiation.

P5024Pathogenic mechanism of DSG2-F531C mutation caused arrhythmogenic right ventricular cardiomyopathy

Abstract Objective Mutations in the Desmoglein-2 (DSG2) are associated with arrhythmogenic right ventricular cardiomyopathy (ARVC). We previously identified a highly conserved F531C (c.1592T&gt;G) variant of the cardiac desmosome gene DSG2 in the proband with a positive family history. The aim of this study is to investigate the mechanism(s) of DSG2-F531C variant in the pathogenesis of ARVC. Methods A large Han Chinese family with five generations was enrolled in this study, physical and clinical examinations were performed. Seven members were diagnosed with ARVC. Subsequently five desmosomal genes (PKP2, DSG2, DSP, DSC2 and JUP), TMEM43 and PLN were sequenced directly from genomic DNA. Seven patients diagnosed with ARVC were homozygous for DSG2-F531C, while five members of the family with normal phenotype were heterozygous for DSG2-F531C. To further explore the role of DSG2-F531C in ARVC pathogenesis, we generated a knock-in (KI) mouse model, which was carrying the mouse equivalent form (DSG2-F536C) of this variant. Results The homozygous KI mice (DSG2-F536C+/+) revealed a robust cardiomyopathy phenotype with left ventricular systolic dysfunction, histopathology showed accumulation of collagen, spotty calcification and fat droplets with extensive fibrosis in ventricular tissue in all DSG2-F536C+/+ mice. Further detections showed widening of the intercalated disc and regional loss of DSG2 in the hearts of these mice. The marked reduction in immunoreactive signal for sodium voltage-gated channel alpha subunit 5 (NaV1.5) was observed with no apparent changes in plakoglobin and connexin-43. In addition, dramatically elevated expression of transforming growth factor β1 (TGF-β1) was also found in the DSG2 mutant mice. Intriguingly, the heterozygous KI mice (DSG2-F536C+/−) expressed a similar level of TGF-β1 versus homozygous ones (DSG2-F536C+/+), but exhibited slight changes in morphology. Conclusions The DSG2-F536C KI mice produce a similar pathological phenotype of human ARVC, which supports DSG2-F531C as a causative mutation for ARVC. Additionally, the DSG2-F536C+/+ mutation induced cardiac fibrosis through the activation of TGF-β1 signaling will open new opportunities for further mechanistic and therapeutic studies in DSG2-related ARVC. Acknowledgement/Funding National Key R&amp;D Program of China [2017YFC0909400); National Key Basic Research Program of China [973 program No. 2013CB531105]

1855-P: Effects of Dapagliflozin and/or Insulin Glargine on Hepatic Steatosis in db/db Mice

Background: Although several studies have shown that SGLT2 inhibitors exert ameliorating effects on hepatic steatosis, the mechanism remains unknown. Therefore, we compare the glucose-lowering effects of the SGLT2 inhibitor, dapagliflozin on hepatic steatosis with those of insulin glargine. Methods: Six-week-old db/db mice were assigned to one of four groups: untreated (Placebo), treated with dapagliflozin (Dapa), treated with insulin glargine (Gla), and treated with both dapagliflozin and insulin glargine (Dapa+Gla). After 8 weeks of treatment, blood glucose levels, liver triglyceride (TG) content and liver gene expression profiles were examined. Results: Fed blood glucose levels were significantly lower in the three treatment groups compared with the Placebo group (Placebo 904.2 ± 35.6, Dapa 425.0 ± 26.7, Gla 406.1 ± 25.8, Dapa+Gla 347.3 ± 24.0 mg/dL). HE staining and oil red O staining of the liver revealed that there was high fat and lipid droplets accumulation in the Gla group compared with that in the other three groups. The liver TG content was significantly increased in the Gla group compared with the others (Placebo 24.1 ± 5.7, Dapa 30.6 ± 6.4, Gla 128 ± 25, and Dapa+Gla 54.4 ± 7.1 mg per gram liver). Microarray analysis revealed that Cidea, Cidec and Mogat1 were upregulated in the Gla group compared with the Placebo group. Real-time quantitative PCR revealed that expression levels associated in fatty acid synthesis, such as Fas, Elovl6, Scd1 and Mogat1 significantly upregulated in the Gla group compared with the Placebo group. As for the expression levels of genes related to fatty acid uptake and storage, Cidea and Cidec, elevated in the Gla group compared with the Placebo group. Pparg2, which is associated with Fas, Elovl6, Scd1, Mogat1 and Cidec significantly increased in the Gla group compared with the Placebo group. Conclusion: Hepatic steatosis was prevented in db/db mice, after 8 weeks of treatment with dapagliflozin and/or insulin glargine, but not with insulin glargine alone. Disclosure K. Omori: None. A. Nakamura: Research Support; Self; Boehringer Ingelheim Pharmaceuticals, Inc., Daiichi Sankyo Company, Limited, Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Ono Pharmaceutical Co., Ltd. H. Miyoshi: Research Support; Self; Astellas Pharma Inc., AstraZeneca, Daiichi Sankyo Company, Limited, Eli Lilly and Company, Kowa Pharmaceutical Europe Co. Ltd., Mitsubishi Tanabe Pharma Corporation, MSD, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Taisho Pharmaceutical Co., Ltd., Takeda Pharmaceutical Company Limited. Speaker's Bureau; Self; Astellas Pharma Inc., AstraZeneca, Eli Lilly and Company, Kissei Pharmaceutical Co., Ltd., Kowa Pharmaceutical Europe Co. Ltd., Mitsubishi Tanabe Pharma Corporation, MSD, Novartis Pharmaceuticals Corporation, Novo Nordisk Inc., Ono Pharmaceutical Co., Ltd., Sanofi, Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Company Limited. H. Nomoto: None. H. Kameda: None. K. Cho: None. Y. Terauchi: Advisory Panel; Self; AstraZeneca, Daiichi Sankyo Company, Limited, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novo Nordisk A/S, Sanofi. Research Support; Self; Daiichi Sankyo Company, Limited, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Novartis Pharmaceuticals Corporation, Novo Nordisk A/S, Ono Pharmaceutical Co., Ltd., Sanofi, Shionogi &amp; Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd. Speaker's Bureau; Self; Astellas Pharma Inc., AstraZeneca, Bayer Yakuhin, Ltd., Daiichi Sankyo Company, Limited, Eli Lilly and Company, Merck Sharp &amp; Dohme Corp., Mitsubishi Tanabe Pharma Corporation, Novartis Pharmaceuticals Corporation, Novo Nordisk A/S, Ono Pharmaceutical Co., Ltd., Sanofi, Sanwa Kagaku Kenkyusho, Shionogi &amp; Co., Ltd., Sumitomo Dainippon Pharma Co., Ltd. T. Atsumi: Research Support; Self; Astellas Pharma Inc., Bayer Yakuhin, Ltd., Chugai Pharmaceutical Co., Ltd., Daiichi Sankyo Company, Limited, Eisai Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Takeda Pharmaceutical Company Limited. Speaker's Bureau; Self; AbbVie Inc., Astellas Pharma Inc., Bristol-Myers Squibb Company, Chugai Pharmaceutical Co., Ltd., Eisai Co., Ltd., Eli Lilly and Company, Mitsubishi Tanabe Pharma Corporation, Pfizer Inc., Takeda Pharmaceutical Company Limited, UCB, Inc. Funding AstraZeneca

MicroRNA-16–5p promotes 3T3-L1 adipocyte differentiation through regulating EPT1

Adipogenesis is an organized process of cellular differentiation by which pre-adipocytes differentiate towards mature adipocytes. miR-16–5p has been reported to be involved in cell proliferation, apoptosis, differentiation and angiogenesis. However little is known about miR-16–5p functional role in 3T3-L1 adipocyte differentiation. In this study, we found that miRNA-16–5p was significantly upregulated during 3T3-L1 preadipocytes differentiation towards mature adipocytes. Over-expression of miRNA-16–5p promoted mature adipocytes specific genes expression and fat droplet accumulation in vitro and in vivo. Meanwhile we have identified EPT1 as the target gene of miRNA-16–5p. Taken together, our data provided evidence to support that miRNA-16–5p promotes adipocyte differentiation by suppressing EPT1.

Bioactive fraction from Lagerstroemia speciosa leaves (DLBS3733) reduces fat droplet by inhibiting adipogenesis and lipogenesis.

Background: Obesity has become a risk factor for metabolic diseases. One of the cellular characteristics of obesity is the occurrence of adipose cells hyperplasia. Lagerstroemia speciosa is a plant which has been used for the treatment of diabetes. Furthermore, some studies also indicated that L. speciosa possesses antiobesity activity. Its antiobesity activity was examined in the present study through adipogenesis, lipogenesis, and lipolysis pathways.Aim: DLBS3733, a bioactive fraction of L. speciosa, was explored for its potential benefits to alter obesity through adipogenesis and lipogenesis inhibition and lipolysis induction activity.Materials and methods: This study was performed using 3T3-L1 cells. mRNA level and protein expressions related to adipogenesis, lipogenesis, and lipolysis pathways were assayed in this study.Results: Antiadipogenic effects of DLBS3733 (15 µg/mL) were found to be mediated by a significant downregulation of mRNA level of multicomponents involved in adipogenesis which include C/EBPα (CCAAT/enhancer-binding protein alpha) and PPAR-γ (peroxisome proliferator-activated receptor gamma) by 75% and 80.1% (p<0.05), respectively. DLBS3733 was found to inhibit lipogenesis, as shown by the significant reductions of adiponectin excretion and mRNA level of fatty acid synthase, SREBP (sterol regulatory element-binding protein), and ACC-β (Acetyl-CoA carboxylase) by 44.7%, 70.9%, and 83.1%, respectively (p<0.05). In addition, DLBS3733 was found to inhibit fat droplets accumulation in the cells in a dose-dependent manner through Oil-Red O staining. pAMPK protein was upregulated by 75% and ACC-β was downregulated by 88% (p<0.05) which indicates the reduction of lipid synthesis. Meanwhile, DLBS3733 showed an insignificant effect on adipose triglyceride lipase, hormone-sensitive lipase, and carnitine palmitoyl-CoA transferase-1 which indicate that DLBS3733 does not induce lipolysis.Conclusion: These results demonstrate the inhibitory activity of DLBS3733 on adipogenesis and lipogenesis. DLBS3733 may provide an effective and potential benefit in the prevention of obesity.

The Presence of Fat Droplets in the Retina of Rats in a Model of Fat Embolism

IntroductionFat embolism (FE) induced in rats by intravenous injection (IV) of the neutral fat triolein (T) results in the deposition of intrapulmonary lipid associated with septal and arterial inflammation. In humans, FE may also contribute to retinopathy. This study's goal is to determine the presence of fat droplets in the retina in our rat model at a time when pulmonary fat is known to accumulate.Material and MethodsSprague‐Dawley rats (250–300g) were injected with 0.2 ml of T (N=13) in the caudal vein; controls received injection of saline (N=13). 48 hours later, rats were euthanized using decapitation under isoflurane anesthesia. Lungs were dissected, frozen immediately and stored for histological analysis. Eyes were dissected and incubated in PBS at 4°C for two hours. The retinas were isolated, flattened into optimal cutting temperature (OCT) compound by making four peripheral incisions at 90° intervals, and frozen immediately in isopentane equilibrated to −80°C. Cryosections of five representative experimental and control samples were stained with Oil Red O to detect fat. Three independent samples from each animal were stained. Two pathologists blinded to the identity of the samples analyzed the samples for presence of Oil Red O‐positive fat droplets.ResultsForty‐eight hours after T injection, all experimental animals exhibited large lipid droplets in the outer retina, indicated by the deep red Oil Red O staining. Lipid droplets were absent in retinas of saline injected controls. The lipid droplets typically span the outer segments, outer nuclear, and outer plexiform layers with some extending through the inner nuclear layer and into the inner plexiform layer. No lipid droplets observed in the inner retina or extending into the retinal ganglion cell layer. T‐treated rats also had the expected large fat droplets in the lungs, mostly in the alveoli with an inflammatory response in the parenchyma; while the saline treated animals showed only a small number of droplets.ConclusionsFat droplets were observed within the eyes in T‐injected rats at 48 hours following injection and were predominantly located within the outer retina. As previously described, the lungs has significant accumulation of fat droplets. This animal model could serve as a novel model for studying retinopathy subsequent to fat embolism in human patients. Future studies should include longitudinal analyses of fat embolism in the retina and resulting structural damage and functional impairment at different post injection intervals. It is proposed that the underlying pathogenesis may involve alterations in the renin‐angiotensin system as suggested for the lung.Support or Funding InformationSupported by the Catherine T Geldmacher foundation, Saint Louis, MO.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Lycopene inhibits hepatic stellate cell activation and modulates cellular lipid storage and signaling.

Hepatic stellate cells are liver-specific perivascular cells, identified as the major source of collagen in liver fibrosis, following their activation and conversion to myofibroblast-like cells. Lycopene is a carotenoid with biological activities and protective effects described in different pathologies, but little is known about its role in liver protection. We evaluated the influence of lycopene on the cell cycle and lipid metabolism and monitored the possible pathways involved in lycopene inhibition of stellate cell activation. Lycopene induced expression of the lipocyte phenotype, with an accumulation of fat droplets in cytoplasm, with high synthesis and turnover of phospholipids and triglycerides. Cell proliferation analysis showed that lycopene reduced the growth of GRX cells. Lycopene induced an arrest in the G0/G1 phase, followed by a decrease of cells in the G2/M phase, regardless of the concentration of lycopene used. Lycopene modulated relevant signaling pathways related to cholesterol metabolism, cellular proliferation, and lipid metabolism. Also, lycopene treatment increased the expression of RXR-α, RXR-β, and PPARγ, important biomarkers of liver regeneration. These results show that lycopene was able to negatively modulate events related to the activation of hepatic stellate cells through mechanisms that involve changes in expression of cellular lipid metabolism factors, and suggest that this compound might provide a novel pharmacological approach for the prevention and treatment of fibrotic liver diseases.

MiR-454 regulates triglyceride synthesis in bovine mammary epithelial cells by targeting PPAR-γ

Triglycerides account for 99% of milk fat and play a central role in determining dairy product quality. Many factors influence triglyceride synthesis and milk fat secretion. MicroRNAs have been verified to be involved in numerous biological processes, but little is known about their roles in milk fat biosynthesis. In this study, we aim to explore whether miR-454 could regulate triglyceride synthesis in bovine mammary epithelial cells (BMECs) by targeting PPAR-γ. A luciferase reporter assay showed that the predicted target site was correct and that miR-454 and PPAR-γ had a direct interaction. In addition, miR-454 mimics and inhibitors were transfected into BMECs. The results showed that both the mRNA and protein levels of PPAR-γ were negatively correlated with miR-454 expression. Fat droplet accumulation and triglyceride production were also inversely correlated with miR-454 expression. Our results indicate that miR-454 regulates triglyceride synthesis by directly targeting the PPAR-γ 3′ UTR in BMECs, suggesting that miR-454 could potentially be a new factor to elevate dairy product quality.

Konjac glucomannans attenuate diet-induced fat accumulation on livers and its regulation pathway

As one typical dietary fiber, Konjac glucomannan (KGM) is applied to investigate its influence on high-fat diet (HFD) induced liver dysbiosis. The current results indicated dietary KGM was associated with a declined accumulation of fat droplets on animal livers with significantly improved serum lipid compositions through a reduced biosynthesis of free fatty acid, ceramides, and oxidized-triacylglycerols, benefiting the attenuation of oxidative levels. This is the first study to reveal that KGM intervention led an increased level of hydrophilic bile acids and a reduced content of hydrophobic ones in feces. The associated lipid regulatory pathways of AMPK, PPAR and fatty acid metabolism were significantly enriched following KGM intervention. It highlights that the activation of the PI3K pathway and modulation of the expression of the adipogenic regulators of LXR and PPARγ might be the key manipulation patterns of KGM on the attenuation of liver dysbiosis induced by HFD.

Mango leaf tea promotes hepatoprotective effects in obese rats

As mango leaf tea contains mangiferin and other bioactive compounds, this study investigated its anti-inflammatory, antioxidant and hepatoprotective effects on rats with high-fat induced obesity. Three groups were established: a control group (AIN93M diet), an obese group (high-fat diet HFD) and a treatment group (HFD with mango leaf tea for 8 weeks). Mango leaf tea increased antioxidant enzymes, total antioxidant capacity, AdipoR2 and PPAR-α mRNA and proteins expressions and, it also inhibited the NF-κB p65 and SREBP1c genes expressions in the liver. This beverage also leads to Cpt1 overexpression and a significant decrease in the accumulation of fat droplets, improving the hepatic steatosis. Molecular docking suggested a positive interaction between mangiferin, the main bioactive compound of mango leaf tea, and PPAR-α. Mango leaf tea exhibited a hepatoprotective effect through activating PPARα and decreasing the NF-κB p65 expressions, reducing oxidative stress and steatosis, and improving the lipid metabolism.

Fat composition in infant formula contributes to the severity of necrotising enterocolitis.

Necrotising enterocolitis (NEC) is a devastating disease that typically affects formula-fed premature infants, suggesting that dietary components may influence disease pathogenesis. TAG are the major fat components of infant formula, and their digestion requires pancreatic lipases, which may be naturally deficient in premature neonates. We hypothesise that NEC develops partly from the accumulation of incompletely digested long-chain TAG-containing unsaturated fatty acids within the intestinal epithelial cells, leading to oxidative stress and enterocyte damage. We further hypothesise that the administration of a formula that contains reduced TAG ('pre-digested fat') that do not require lipase action may reduce NEC severity. To test these hypotheses, we induced NEC in neonatal mice using three different fat formulations, namely 'standard fat', 'pre-digested fat' or 'very low fat', and determined that mice fed 'standard fat' developed severe NEC, which was significantly reduced in mice fed 'pre-digested fat' or 'very low fat'. The expression level of the critical fat-digesting enzyme carboxyl ester lipase was significantly lower in the newborn compared with older pups, leading to impaired fat digestion. The accumulation of mal-digested fat resulted in the significant accumulation of fat droplets within the intestinal epithelium of the distal ileum, resulting in the generation of reactive oxygen species and intestinal inflammation. Strikingly, these changes were prevented in pups fed 'pre-digested fat' or 'very low fat' formulas. These findings suggest that nutritional formula containing a pre-digested fat system may overcome the natural lipase deficiency of the premature gut, and serve as a novel approach to prevent NEC.

Cannabidiol attenuates alcohol-induced liver steatosis, metabolic dysregulation, inflammation and neutrophil-mediated injury

Cannabidiol (CBD) is a non-psychoactive component of marijuana, which has anti-inflammatory effects. It has also been approved by FDA for various orphan diseases for exploratory trials. Herein, we investigated the effects of CBD on liver injury induced by chronic plus binge alcohol feeding in mice. CBD or vehicle was administered daily throughout the alcohol feeding study. At the conclusion of the feeding protocol, serums samples, livers or isolated neutrophils were utilized for molecular biology, biochemistry and pathology analysis. CBD significantly attenuated the alcohol feeding-induced serum transaminase elevations, hepatic inflammation (mRNA expressions of TNFα, MCP1, IL1β, MIP2 and E-Selectin, and neutrophil accumulation), oxidative/nitrative stress (lipid peroxidation, 3-nitrotyrosine formation, and expression of reactive oxygen species generating enzyme NOX2). CBD treatment also attenuated the respiratory burst of neutrophils isolated from chronic plus binge alcohol fed mice or from human blood, and decreased the alcohol-induced increased liver triglyceride and fat droplet accumulation. Furthermore, CBD improved alcohol-induced hepatic metabolic dysregulation and steatosis by restoring changes in hepatic mRNA or protein expression of ACC-1, FASN, PPARα, MCAD, ADIPOR-1, and mCPT-1. Thus, CBD may have therapeutic potential in the treatment of alcoholic liver diseases associated with inflammation, oxidative stress and steatosis, which deserves exploration in human trials.

Kupffer cells activation promoted binge drinking-induced fatty liver by activating lipolysis in white adipose tissues.

Kupffer cells (KCs) have been suggested to play critical roles in chronic ethanol induced early liver injury, but the role of KCs in binge drinking-induced hepatic steatosis remains unclear. This study was designed to investigate the roles of KCs inhibitor (GdCl3) and TNF-α antagonist (etanercept) on binge drinking-induced liver steatosis and to explore the underlying mechanisms. C57BL/6 mice were exposed to three doses of ethanol (6g/kg body weight) to mimic binge drinking-induced fatty liver. The results showed that both GdCl3 and etanercept partially but significantly alleviated binge drinking-induced increase of hepatic triglyceride (TG) level, and reduced fat droplets accumulation in mice liver. GdCl3 but not etanercept significantly blocked binge drinking-induced activation of KCs. However, neither GdCl3 nor etanercept could affect binge drinking-induced decrease of PPAR-α, ACOX, FAS, ACC and SCD protein levels, or increase of the LC3 II/LC3 I ratio and p62 protein level. Interestingly, both GdCl3 and etanercept significantly suppressed binge drinking-induced phosphorylation of HSL in epididymal adipose tissues. Results of in vitro studies with cultured epididymal adipose tissues showed that TNF-α could increase the phosphorylation of HSL in adipose tissues and upgrade the secretion of free fatty acid (FFA) in the culture medium. Taken together, KCs inhibitor and TNF-α antagonist could partially attenuate binge drinking-induced liver steatosis, which might be attributed to the suppression of mobilization of white adipose tissues. These results suggest that KCs activation may promote binge drinking-induced fatty liver by TNF-α mediated activation of lipolysis in white adipose tissues.

Inactivation of TNF/LT locus alters mouse metabolic response to concentrated ambient PM2.5

BackgroundExposure to ambient fine particulate matter (PM2.5) is associated with increased cardiometabolic morbidity and mortality. This is widely believed to be attributable to PM2.5 exposure-induced pulmonary and subsequent systemic inflammation. Tumor necrosis factor alpha (TNFα), lymphotoxin α (LTα), and lymphotoxin β (LTβ) are three homologous pro-inflammatory cytokines, each with both unique and redundant activities in inflammation. Their role in PM2.5 exposure-induced inflammation and adverse cardiometabolic effects has to be determined. Methods and resultsLTα/TNFα/LTβ triple-knockout (TNF/LT KO) and wildtype (WT) mice were exposed to concentrated ambient PM2.5 (CAP) for 5 months. Lung pathological analysis revealed that TNF/LT deficiency reduced CAP exposure-induced pulmonary inflammation. However, glucose homeostasis assessments showed that TNF/LT deficiency significantly aggravated CAP exposure-induced glucose intolerance and insulin resistance. Consistent with glucose homeostasis assessments, CAP exposure significantly increased the body weight and adiposity of TNF/LT KO but not WT mice. In contrast to its body weight effects, CAP exposure reduced food intake of WT but not TNF/LT KO mice. On the other hand, CAP exposure induced marked fat droplet accumulation in brown adipose tissues of WT mice and significantly decreased their uncoupling protein 1 (UCP1) expression, and these effects were markedly exacerbated in TNF/LT KO mice. ConclusionThe present study suggests that TNF/LT deficiency influences PM2.5 exposure-induced response of energy metabolism through alterations in both food intake and energy expenditure.