The Role of Sargahydroquinoic Acid and Sargachromenol in the Anti-Inflammatory Effect of Sargassum yezoense.

The anti-inflammatory effect of the ethanol extract of Sargassum yezoense and its fractions were investigated in this study. The ethanol extract exhibited a strong anti-inflammatory effect on lipopolysaccharide-stimulated RAW 264.7 macrophages and effectively suppressed the M1 polarization of murine bone-marrow-derived macrophages stimulated by lipopolysaccharides and IFN-γ (interferon-gamma). Through a liquid-liquid extraction process, five fractions (n-hexane, chloroform, ethyl acetate, butanol, and aqueous) were acquired. Among these fractions, the chloroform fraction (SYCF) was found to contain the highest concentration of phenolic compounds, along with two primary meroterpenoids, sargahydroquinoic acid (SHQA) and sargachromenol (SCM), and exhibit significant antioxidant capacity. It also demonstrated a robust anti-inflammatory effect. A direct comparison was conducted to assess the relative contribution of SHQA and SCM to the anti-inflammatory properties of SYCF. The concentrations of SHQA and SCM tested were determined based on their relative abundance in SYCF. SHQA contributed to a significant portion of the anti-inflammatory property of SYCF, while SCM played a limited role. These findings not only highlight the potential of the chloroform-ethanol fractionation approach for concentrating meroterpenoids in S. yezoense but also demonstrate that SHQA and other bioactive compounds work additively or synergistically to produce the potent anti-inflammatory effect of SYCF.

Suppression of Pro-Inflammatory M1 Polarization of LPS-Stimulated RAW 264.7 Macrophage Cells by Fucoxanthin-Rich Sargassum hemiphyllum.

Macrophages play an important role in managing the onset and progression of chronic inflammatory diseases. The primary objective of this study is to explore the antioxidant potential and anti-inflammatory properties of Sargassum hemiphyllum ethanol extract (SHE) and its fraction. SHE and its five constituent fractions were assessed for overall antioxidant capabilities and inhibitory effects on LPS-induced inflammation by modulating macrophages polarization in both RAW 264.7 macrophages and bone-marrow-derived macrophages (BMDM). Among the organic solvent fractions of SHE, the ethyl acetate fraction displayed the highest total phenolic content and total antioxidant capacity. Notably, the n-hexane (Hex) fraction showed the most substantial suppression of LPS-induced tumor necrosis factor α secretion in BMDM among the five fractions of SHE. The SHE and Hex fraction significantly reduced the heightened expression of pro-inflammatory cytokines and inflammation-inducible enzymes induced by LPS in RAW 264.7 macrophages. In particular, the SHE and Hex fraction inhibited M1 macrophage polarization by reducing the mRNA expression of M1 macrophage markers in macrophages that were polarized toward the M1 phenotype. Furthermore, the SHE and Hex fraction attenuated the induction in nuclear factor E2-related factor 2 and its target genes, which was accompanied by an alteration in antioxidant gene expression in M1-polarized BMDM. The findings suggest that both SHE and its Hex fraction exhibit inhibitory effects on LPS-triggered inflammation and oxidative stress by modulating the polarization of M1 macrophages within macrophage populations.

Gut microbiome-derived glycine lipids are diet-dependent modulators of hepatic injury and atherosclerosis.

Oral and gut Bacteroidetes produce unique classes of serine-glycine lipodipeptides and glycine aminolipids that signal through host Toll-like receptor 2. These glycine lipids have also been detected in human arteries, but their effects on atherosclerosis are unknown. Here, we sought to investigate the bioactivity of bacterial glycine lipids in mouse models of atherosclerosis. Lipid 654 (L654), a serine-glycine lipodipeptide species, was first tested in a high-fat diet (HFD)-fed Ldlr-/- model of atherosclerosis. Intraperitoneal administration of L654 over 7 weeks to HFD-fed Ldlr-/- mice resulted in hypocholesterolemic effects and significantly attenuated the progression of atherosclerosis. We found that L654 also reduced liver inflammatory and extracellular matrix gene expression, which may be related to inhibition of macrophage activation as demonstrated in vivo by lower major histocompatibility complex class II gene expression and confirmed in cell experiments. In addition, L654 and other bacterial glycine lipids in feces, liver, and serum were markedly reduced alongside changes in Bacteroidetes relative abundance in HFD-fed mice. Finally, we tested the bioactivities of L654 and related lipid 567 in chow-fed Apoe-/- mice, which displayed much higher fecal glycine lipids relative to HFD-fed Ldlr-/- mice. Administration of L654 or lipid 567 for 7 weeks to these mice reduced the liver injury marker alanine aminotransferase, but other effects seen in Ldlr-/- were not observed. Therefore, we conclude that conditions in which gut microbiome-derived glycine lipids are lost, such as HFD, may exacerbate the development of atherosclerosis and liver injury, whereas correction of such depletion may protect from these disorders.

The loss of histone deacetylase 4 in macrophages exacerbates hepatic and adipose tissue inflammation in male but not in female mice with diet-induced non-alcoholic steatohepatitis.

Epigenetic regulation in macrophages plays a crucial role in the inflammatory response of cells. We investigated the role of macrophage histone deacetylase 4 (HDAC4) in diet-induced obesity and non-alcoholic steatohepatitis using macrophage-specific Hdac4 knockout mice (Hdac4MKO ). Hdac4 floxed control (Hdac4fl/fl ) and Hdac4MKO mice were fed a regular chow diet or an obesogenic high-fat/high-sucrose/high-cholesterol (HF/HS/HC) diet for 12 weeks. The loss of macrophage Hdac4, compared with Hdac4fl/fl control, aggravated the diet-induced inflammation in the liver and white adipose tissue only in male mice. Splenic monocytes isolated from male mice fed the HF/HS/HC diet showed increased lipopolysaccharide (LPS) sensitivity and decreased Ly6C-/Ly6C+ ratios in male Hdac4MKO mice, but not in females. Bone marrow-derived macrophages (BMMs) from male Hdac4MKO mice had a lesser efferocytotic capacity but higher proinflammatory gene expression upon LPS stimulation than male Hdac4fl/fl mice. However, female Hdac4MKO BMMs exhibited the opposite responses. The induction of estrogen receptor α (ERα, Esr1) expression by LPS was less in male but more in female Hdac4MKO BMMs than Hdac4fl/fl BMMs. Moreover, overexpression of human HDAC4 decreased basal expression of Esr1 and abolished its induction by LPS. Inhibition of ERα increased Hdac4 with induction of inflammatory genes, whereas activation of ERα decreased Hdac4 with reduction of inflammatory genes in male and female Hdac4fl/fl BMMs treated with LPS. However, regardless of the inhibition or activation of ERα, proinflammatory genes were induced by LPS more in male Hdac4MKO BMMs than Hdac4fl/fl cells, whereas cells in females showed opposite responses. In conclusion, this study suggests that the lack of macrophage Hdac4 aggravates hepatic and white adipose inflammation in male mice with diet-induced obesity and non-alcoholic steatohepatitis, and not in female mice. HDAC4 and ERα appear to counteract each other, but ERα may not be a major player in sex-dependent inflammatory responses in macrophages deficient in HDAC4. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The effect of cranberry consumption on lipid metabolism and inflammation in human apo A-I transgenic mice fed a high-fat and high-cholesterol diet.

Lipid metabolism and inflammation contribute to CVD development. This study investigated whether the consumption of cranberries (CR; Vaccinium macrocarpon) can alter HDL metabolism and prevent inflammation in mice expressing human apo A-I transgene (hApoAITg), which have similar HDL profiles to those of humans. Male hApoAITg mice were fed a modified American Institute of Nutrition-93M high-fat/high-cholesterol diet (16 % fat, 0·25 % cholesterol, w/w; n 15) or the high-fat/high-cholesterol diet containing CR (5 % dried CR powder, w/w, n 16) for 8 weeks. There were no significant differences in body weight between the groups. Serum total cholesterol, non-HDL-cholesterol and TAG concentrations were significantly lower in the control than CR group with no significant differences in serum HDL-cholesterol and apoA-I. Mice fed CR showed significantly lower serum lecithin-cholesterol acyltransferase activity than the control. Liver weight and steatosis were not significantly different between the groups, but hepatic expression of genes involved in cholesterol metabolism was significantly lower in the CR group. In the epididymal white adipose tissue (eWAT), the CR group showed higher weights with decreased expression of genes for lipogenesis and fatty acid oxidation. The mRNA abundance of F4/80, a macrophage marker and the numbers of crown-like structures were less in the CR group. In the soleus muscle, the CR group also demonstrated higher expression of genes for fatty acid ß-oxidation and mitochondrial biogenesis than those of the control. In conclusion, although CR consumption elicited minor effects on HDL metabolism, it prevented obesity-induced inflammation in eWAT with concomitant alterations in soleus muscle energy metabolism.

Fucoxanthin inhibits lipopolysaccharide-induced inflammation and oxidative stress by activating nuclear factor E2-related factor 2 via the phosphatidylinositol 3-kinase/AKT pathway in macrophages.

PURPOSE: Anti-inflammatory and antioxidant effects of fucoxanthin (FCX), a xanthophyll carotenoid, have been suggested. However, underlying mechanisms are elusive. The objective of this study was to elucidate the mechanisms by which FCX and its metabolites inhibit lipopolysaccharide (LPS)-induced inflammation and oxidative stress in macrophages. METHODS: The effects of the FCX on mRNA and protein expression of pro-inflammatory cytokines and antioxidant genes, and reactive oxygen species (ROS) accumulation were determined in RAW 264.7 macrophages. A potential role of FCX in the modulation of phosphatidylinositol 3-kinase (PI3K)/AKT/nuclear E2-related factor 2 (NRF2) axis was evaluated. RESULTS: FCX significantly decreased LPS-induced interleukin (Il)6, Il1b, and tumor necrosis factor α (Tnf) mRNA abundance and TNFα secretion. FCX attenuated LPS or tert-butyl-hydroperoxide-induced ROS accumulation with concomitant increases in the expression of antioxidant enzymes. Also, trolox equivalent antioxidant capacity assay demonstrated that FCX had a potent free radical scavenging property. FCX markedly increased nuclear translocation of NRF2 in LPS-treated macrophages, consequently inducing its target gene expression. Interestingly, the effect of FCX on NRF2 nuclear translocation was noticeably diminished by LY294002, an inhibitor of PI3K, but not by inhibitors of mitogen-activated protein kinases. Phosphorylation of AKT, a downstream element of PI3K, was also markedly increased by FCX. FCX metabolites, such as fucoxanthinol and amarouciaxanthin A, significantly attenuated LPS-induced ROS accumulation and pro-inflammatory cytokine expression. CONCLUSION: FCX exerts anti-inflammatory and antioxidant effects by the activation of NRF2 in the macrophages activated by LPS, which is mediated, at least in part, through the PI3K/AKT pathway.

Fucoxanthin exerts anti-fibrogenic effects in hepatic stellate cells.

The objective of this study was to evaluate whether fucoxanthin (FCX) have anti-fibrogenic properties in hepatic stellate cells (HSCs). FCX significantly decreased basal and transforming growth factor ß1 (TGFß1)-induced mRNA levels of fibrogenic genes with concomitant decreases in their protein levels in LX-2 cells. The phosphorylation of SMA- and MAD-related protein (SMAD3) was increased by TGFß1, which was attenuated by FCX. Importantly, when LX-2 cells were treated with FCX and SIS3, a SMAD3 inhibitor, there was synergistic repression of fibrogenic gene expression. The anti-fibrogenic effect of FCX was also confirmed in primary human HSCs. FCX prevented TGFß1-induced accumulation of reactive oxygen species by diminishing mRNA level of NADPH oxidase 4 (NOX4) in LX-2 cells. When FCX was present during the activation of quiescent mouse primary HSCs, it decreased the expression of fibrogenic genes while diminishing intracellular lipid droplets. The results suggest that FCX exerts an anti-fibrogenic effect in HSCs primarily by preventing TGFß1-induced pro-fibrogenic genes expression via inhibition of SMAD3 activation and by inhibiting the activation of quiescent HSCs.

Spirulina supplementation in a mouse model of diet-induced liver fibrosis reduced the pro-inflammatory response of splenocytes.

Treatment of liver fibrosis is very limited as there is currently no effective anti-fibrotic therapy. Spirulina platensis (SP) is a blue-green alga that is widely supplemented in healthy foods. The objective of this study was to determine whether SP supplementation can prevent obesity-induced liver fibrosis in vivo. Male C57BL/6J mice were randomly assigned to a low-fat or a high-fat (HF)/high-sucrose/high-cholesterol diet or an HF diet supplemented with 2·5 % SP (w/w) (HF/SP) for 16 or 20 weeks. There were no significant differences in body weight, activity, energy expenditure, serum lipids or glucose tolerance between mice on HF and HF/SP diets. However, plasma alanine aminotransferase level was significantly reduced by SP at 16 weeks. Expression of fibrotic markers and trichrome stains showed no differences between HF and HF/SP. Splenocytes isolated from HF/SP fed mice had lower inflammatory gene expression and cytokine secretion compared with splenocytes from HF-fed mice. SP supplementation did not attenuate HF-induced liver fibrosis. However, the expression and secretion of inflammatory genes in splenocytes were significantly reduced by SP supplementation, demonstrating the anti-inflammatory effects of SP in vivo. Although SP did not show appreciable effect on the prevention of liver fibrosis in this mouse model, it may be beneficial for other inflammatory conditions.

Kirenol inhibits adipogenesis through activation of the Wnt/ß-catenin signaling pathway in 3T3-L1 adipocytes.

Kirenol, a natural diterpenoid compound, has been reported to possess anti-oxidant, anti-inflammatory, anti-allergic, and anti-arthritic activities; however, its anti-adipogenic effect remains to be studied. The present study evaluated the effect of kirenol on anti-adipogenesis through the activation of the Wnt/ß-catenin signaling pathway. Kirenol prevented intracellular lipid accumulation by down-regulating key adipogenesis transcription factors [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding proteins α (C/EBPα), and sterol regulatory element binding protein-1c (SREBP-1c)] and lipid biosynthesis-related enzymes [fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC)], as well as adipocytokines (adiponectin and leptin). Kirenol effectively activated the Wnt/ß-catenin signaling pathway, in which kirenol up-regulated the expression of low density lipoprotein receptor related protein 6 (LRP6), disheveled 2 (DVL2), ß-catenin, and cyclin D1 (CCND1), while it inactivated glycogen synthase kinase 3ß (GSK3ß) by increasing its phosphorylation. Kirenol down-regulated the expression levels of PPARγ and C/EBPα, which were up-regulated by siRNA knockdown of ß-catenin. Overall, kirenol is capable of inhibiting the differentiation and lipogenesis of 3T3-L1 adipocytes through the activation of the Wnt/ß-catenin signaling pathway, suggesting its potential as natural anti-obesity agent.

Dietary sugar kelp (Saccharina latissima) consumption did not attenuate atherosclerosis in low-density lipoprotein receptor knockout mice.

We previously demonstrated the beneficial effects of U.S.-grown sugar kelp (Saccharina latissima), a brown seaweed, on reducing serum triglycerides (TG) and total cholesterol (TC) and protecting against inflammation and fibrosis in the adipose tissue of diet-induced obesity mice. In this current study, we aimed to explore whether the dietary consumption of sugar kelp can prevent atherosclerosis using low-density lipoprotein receptor knockout (Ldlr KO) mice fed an atherogenic diet. Eight-week-old male Ldlr KO mice were fed either an atherogenic high-fat/high-cholesterol control (HF/HC) diet or a HF/HC diet supplemented with 6% (w/w) sugar kelp (HF/HC-SK) for 16 weeks. Consumption of sugar kelp significantly increased the body weight gain without altering fat mass and lean mass. Also, there were no significant differences in energy expenditure and physical activities between the groups. The two groups did not show significant differences in serum and hepatic TG and TC levels or the hepatic expression of genes involved in cholesterol and lipid metabolism. Although serum alanine aminotransferase (ALT) activity did not differ significantly between the two groups, there were significant increases in the expression of macrophage markers, including adhesion G protein-coupled receptor E1 and cluster of differentiation 68, as well as tumor necrosis factor alpha in the HF/HC-SK group compared to the HF/HC mice. The consumption of sugar kelp did not elicit a significant effect on the development of aortic lesions. Moreover, lipopolysaccharide-stimulated splenocytes isolated from HF/HC-SK-fed mice showed no significant changes in the mRNA levels of pro-inflammatory genes compared with those from the HF/HC mice. In summary, the consumption of dietary sugar kelp did not elicit anti-atherogenic and hepatoprotective effects in Ldlr KO mice.

Bacterioruberin extract from Haloarchaea Haloferax marinum: Component identification, antioxidant activity and anti-atrophy effect in LPS-treated C2C12 myotubes.

Carotenoids are natural pigments utilized as colourants and antioxidants across food, pharmaceutical and cosmetic industries. They exist in carbon chain lengths of C30, C40, C45 and C50, with C40 variants being the most common. Bacterioruberin (BR) and its derivatives are part of the less common C50 carotenoid group, synthesized primarily by halophilic archaea. This study analysed the compositional characteristics of BR extract (BRE) isolated from 'Haloferax marinum' MBLA0078, a halophilic archaeon isolated from seawater near Yeoungheungdo Island in the Republic of Korea, and investigated its antioxidant activity and protective effect on lipopolysaccharide (LPS)-induced C2C12 myotube atrophy. The main components of BRE included all-trans-BR, monoanhydrobacterioruberin, 2-isopentenyl-3,4-dehydrorhodopin and all-trans-bisanhydrobacterioruberin. BRE exhibited higher antioxidant activity and DNA nicking protection activity than other well-known C40 carotenoids, such as ß-carotene, lycopene and astaxanthin. In C2C12 myotubes, LPS treatment led to a reduction in myotube diameter and number, as well as the hypertranscription of the muscle-specific ubiquitin ligase MAFbx and MuRF1. BRE mitigated these changes by activating the Akt/mTOR pathway. Furthermore, BRE abolished the elevated cellular reactive oxygen species levels and the inflammation response induced by LPS. This study demonstrated that 'Hfx. marinum' is an excellent source of natural microbial C50 carotenoids with strong antioxidant capacity and may offer potential protective effects against muscle atrophy.

5,7-Dimethoxyflavone, an activator of PPARα/γ, inhibits UVB-induced MMP expression in human skin fibroblast cells.

Peroxisome proliferator-activated receptors (PPARs), which are members of the nuclear hormone receptor superfamily, are a family of ligand-activated transcription factors that consist of three isotypes (PPAR α, δ and γ). PPAR activity was previously thought to be limited to lipid metabolism and glucose homeostasis; however, intensive studies of PPARα/γ in recent years have revealed their importance in age-related inflammation and photoaging as regulators of cytokines, matrix metalloproteinases (MMPs) and nuclear factor-kappa B (NF-κB). We evaluated the ability of the PPARα/γ activator 5,7-dimethoxyflavone (5,7-DMF) to inhibit ultraviolet B (UVB)-induced MMP expression in Hs68 human skin fibroblasts. Hs68 cells were treated with 5,7-DMF and then exposed to UVB irradiation. MMP expression, production and activity were determined by reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay and gelatin zymography. PPARα/γ expression, catalase expression, and mitogen-activated protein kinase (MAPK), activator protein-1 (AP-1) and NF-κB signalling were evaluated by Western blot analysis. PPARα/γ activity was assessed with the GAL4/PPARα/γ transactivation assay. We found that 5,7-DMF strongly decreased MMP expression, production and activity. In addition, 5,7-DMF significantly increased PPARα/γ activation and catalase expression, thereby downregulating UVB-induced reactive oxygen species (ROS) production, ROS-induced MAPK signalling and downstream transcription factors. Finally, 5,7-DMF reduced IκBα phosphorylation, blocked NF-κB p65 nuclear translocation, strongly suppressed proinflammatory cytokines such as interleukin-6 (IL-6) and IL-8. 5,7-DMF prevents UVB-induced MMP expression by suppressing UVB-induced oxidative stress and age-related inflammation via NF-κB and MAPK/AP-1 pathways. Our findings suggest the usefulness of 5,7-DMF for preventing and treating skin photoaging.

Boesenbergia pandurata attenuates diet-induced obesity by activating AMP-activated protein kinase and regulating lipid metabolism.

Obesity, a chronic metabolic disorder, is characterized by enlarged fat mass and dysregulation of lipid metabolism. The medicinal plant, Boesenbergia pandurata (Roxb.) Schltr., has been reported to possess anti-oxidative and anti-inflammatory properties; however, its anti-obesity activity is unexplored. The present study was conducted to determine whether B. pandurata extract (BPE), prepared from its rhizome parts, attenuated high-fat diet (HFD)-induced obesity in C57BL/6J mice. The molecular mechanism was investigated in 3T3-L1 adipocytes and HepG2 human hepatoma cells. BPE treatment decreased triglyceride accumulation in both 3T3-L1 adipocytes and HepG2 hepatocytes by activating AMP-activated protein kinase (AMPK) signaling and regulating the expression of lipid metabolism-related proteins. In the animal model, oral administration of BPE (200 mg/kg/day for 8 weeks) significantly reduced HFD-induced body weight gain without altering the amount of food intake. In addition, elevated serum levels of total cholesterol, low-density lipoprotein cholesterol, and triglycerides were suppressed by BPE administration. Fat pad masses were reduced in BPE-treated mice, as evidenced by reduced adipocyte size. Furthermore, BPE protected against the development of nonalcoholic fatty liver by decreasing hepatic triglyceride accumulation. BPE also activated AMPK signaling and altered the expression of lipid metabolism-related proteins in white adipose tissue and liver. Taken together, these findings indicate that BPE attenuates HFD-induced obesity by activating AMPK and regulating lipid metabolism, suggesting a potent anti-obesity agent.

Fucoxanthin Attenuates the Reprogramming of Energy Metabolism during the Activation of Hepatic Stellate Cells.

Hepatic stellate cells (HSC) play a major role in developing liver fibrosis. Upon activation during liver injury, activated HSC (aHSC) increase cell proliferation, fibrogenesis, contractility, chemotaxis, and cytokine release. We previously showed that aHSC have increased mitochondrial respiration but decreased glycolysis compared to quiescent HSC (qHSC). We also demonstrated that fucoxanthin (FCX), a xanthophyll carotenoid, has an anti-fibrogenic effect in HSC. The objective of this study was to investigate whether FCX attenuates metabolic reprogramming occurring during HSC activation. Mouse primary HSC were activated in the presence or absence of FCX for seven days. aHSC displayed significantly decreased glycolysis and increased mitochondrial respiration compared to qHSC, which was ameliorated by FCX present during activation. In addition, FCX partially attenuated the changes in the expression of genes involved in glycolysis and mitochondrial respiration, including hexokinase 1 (Hk1), Hk2, peroxisome proliferator-activated receptor γ coactivator 1ß, and pyruvate dehydrogenase kinase 3. Our data suggest that FCX may prevent HSC activation by modulating the expression of genes crucial for metabolic reprogramming in HSC.

Astaxanthin Attenuates the Changes in the Expression of MicroRNAs Involved in the Activation of Hepatic Stellate Cells.

We previously demonstrated that astaxanthin (ASTX), a xanthophyll carotenoid, has an antifibrogenic effect in hepatic stellate cells (HSC), primarily responsible for the accumulation of extracellular matrix protein during the development of liver fibrosis. Studies have shown that microRNAs (miRNAs) are involved in HSC activation. Therefore, we analyzed the expression of 84 miRNAs using miRNA arrays in primary mouse quiescent HSC (qHSC) and activated HSC (aHSC) treated with/without ASTX during their activation. Compared with qHSC, the expression of 14 miRNAs and 23 miRNAs was increased and decreased by more than 2-fold, respectively, in aHSC. Among the 14 miRNAs increased in aHSC, the expression of miR-192-5p, miR-382-5p, and miR-874-3p was reduced by ASTX. In addition, ASTX increased the expression of miR-19a-3p, miR-19b-3p, and miR-101a-3p among 23 miRNAs decreased in aHSC. Moreover, we confirmed miR-382-5p expression was ~15-fold higher in aHSC than qHSC, and ASTX markedly inhibited the induction measured by quantitative real-time PCR. We identified that the expression of Baz1a and Zfp462 from the predicted miR-382-5p target genes was significantly reduced in aHSC while increased by ASTX treatment similar to the levels in qHSC. The roles of Baz1a and Zfp462 in HSC activation and the antifibrogenic effect of ASTX need to be further investigated.

A mouse model of the regression of alcoholic hepatitis: Monitoring the regression of hepatic steatosis, inflammation, oxidative stress, and NAD+ metabolism upon alcohol withdrawal.

This study aimed to develop a well-characterized mouse model of alcoholic hepatitis (AH) regression. Male C57BL/6J mice were fed a Lieber-DeCarli (LD) control diet or LD containing 5% ethanol for ten days followed by one binge, which is the chronic-binge model of AH developed by the National Institute on Alcohol Abuse and Alcoholism. To determine AH regression, mice previously exposed to ethanol were put on LD control diet and metabolic and inflammatory features were monitored weekly for three weeks. Serum alcohol, total cholesterol, and alanine transaminase levels were increased in ethanol-fed mice, which declined to those of no ethanol controls within one and three weeks after ethanol withdrawal, respectively. Serum malondialdehyde was increased with ethanol feeding, but it was restored to no ethanol control levels within one week. Ethanol-induced changes in the hepatic expression of genes involved in lipogenesis, fatty acid oxidation, ethanol metabolism, and antioxidant response were restored to those of no ethanol controls after 3 weeks of ethanol withdrawal. Also, ethanol-induced hepatic inflammation was gradually decreased during the 3 weeks of ethanol withdrawal. Hepatic nicotinamide adenine dinucleotide (NAD+) levels and the expression of enzymes involved in the NAD+ salvage pathway were decreased by ethanol feeding, which was mitigated after ethanol withdrawal. Ethanol significantly lowered hepatic sirtuin 1 expression, but its levels were restored with ethanol cessation. This study established a mouse model of AH regression, which can be used as a preclinical model to study the potential of dietary bioactives or therapeutic agents on AH regression.

Consumption of Low Dose Fucoxanthin Does Not Prevent Hepatic and Adipose Inflammation and Fibrosis in Mouse Models of Diet-Induced Obesity.

Fucoxanthin (FCX) is a xanthophyll carotenoid present in brown seaweed. The goal of this study was to examine whether FCX supplementation could attenuate obesity-associated metabolic abnormalities, fibrosis, and inflammation in two diet-induced obesity (DIO) mouse models. C57BL/6J mice were fed either a high-fat/high-sucrose/high-cholesterol (HFC) diet or a high-fat/high-sucrose (HFS) diet. The former induces more severe liver injury than the latter model. In the first study, male C57BL/6J mice were fed an HFC diet, or an HFC diet containing 0.015% or 0.03% (w/w) FCX powder for 12 weeks to develop obesity-induced nonalcoholic steatohepatitis (NASH). In the second study, mice were fed an HFS diet or an HFS diet containing 0.01% FCX powder for 8 weeks. FCX did not change body weight gain and serum lipid profiles compared to the HFC or HFS controls. No significant differences were present in liver triglyceride and total cholesterol, hepatic fat accumulation, and serum alanine aminotransferase levels between control and FCX-fed mice regardless of whether they were on an HFC or HFS diet. FCX did not mitigate mRNA abundance of genes involved in lipid synthesis, cholesterol metabolism, inflammation, and fibrosis in the liver and white adipose tissue, while hepatic fatty acid ß-oxidation genes were significantly elevated by FCX in both HFC and HFS feeding studies. Additionally, in the soleus muscle, FCX supplementation significantly elevated genes that regulate mitochondrial biogenesis and fatty acid ß-oxidation, concomitantly increasing mitochondrial DNA copy number, compared with HFC. In summary, FCX supplementation had minor effects on hepatic and white adipose inflammation and fibrosis in two different DIO mouse models.

Nicotinamide riboside supplementation exerts an anti-obesity effect and prevents inflammation and fibrosis in white adipose tissue of female diet-induced obesity mice.

Nicotinamide riboside (NR) is a nicotinamide adenine dinucleotide (NAD+) precursor. We previously reported that NR supplementation prevented the development of liver fibrosis in male mice. However, whether NR exerts a similar effect in females is unknown. Therefore, we determined whether NR supplementation can prevent obesity-induced inflammation and fibrosis in the liver and white adipose tissue (WAT) by providing NAD+ in obese female mice. Female C57BL/6J mice at the age of 8 weeks (young) and 16 weeks (old) were fed a high-fat/high-sucrose/high-cholesterol diet (HF) or HF diet supplemented with NR at 400 mg/kg/d for 20 weeks. While NR had minor effects in young female mice, it significantly reduced body weight gain, fat mass, glucose intolerance, and serum cholesterol levels compared to the HF group in old females. Hepatic NAD+ level tended toward an increase in the NR group (P=.054), but NR did not attenuate serum alanine aminotransferase levels, steatosis, and liver fibrosis in old female mice. However, NR decreased weight and adipocyte size in gonadal WAT (gWAT) of old females. NR also reduced the number of crown-like structures and the expression of inflammatory genes, along with decreases in fibrogenic gene expression and collagen accumulation in gWAT compared with the HF group. Also, old mice fed NR showed increased metabolic rates, physical activity, and energy expenditure compared with the HF. Thus, our results indicated that NR supplementation exerted an anti-obesity effect and prevented the development of inflammation and fibrosis in the WAT of old, but not young, female mice with diet-induced obesity.

Sugar kelp (Saccharina latissima) inhibits hepatic inflammation and fibrosis in a mouse model of diet-induced nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH), closely associated with obesity, is a health concern worldwide. We investigated whether the consumption of U.S.-grown sugar kelp (Saccharina latissima), an edible brown alga, can prevent obesity-associated metabolic disturbances and NASH in a mouse model of diet-induced NASH. Male C57BL/6J mice were fed a low-fat diet, a high-fat/high-sucrose/high-cholesterol diet (HF), or a HF diet containing sugar kelp (HF-Kelp) for 14 weeks. HF-Kelp group showed lower body weight with increased O2 consumption, CO2 production, physical activity, and energy expenditure compared with the HF. In the liver, there were significant decreases in weight, triglycerides, total cholesterol, and steatosis with HF-Kelp. The HF-Kelp group decreased hepatic expression of a macrophage marker adhesion G protein-coupled receptor E1 (Adgre1) and an M1 macrophage marker integrin alpha x (Itgax). HF-Kelp group also exhibited decreased liver fibrosis, as evidenced by less expression of fibrogenic genes and collagen accumulation than those of HF group. In epididymal white adipose tissue (eWAT), HF-Kelp group exhibited decreases in eWAT weight and adipocyte size compared with those of the HF. HF-Kelp group showed decreased expression of collagen type VI alpha 1 chain, Adgre1, Itgax, and tumor necrosis factor α in eWAT. We demonstrated, for the first time, that the consumption of U.S-grown sugar kelp prevented the development of obesity and its associated metabolic disturbances, steatosis, inflammation, and fibrosis in the liver and eWAT of a diet-induced NASH mouse model.

Anthocyanin-Rich Aronia Berry Extract Mitigates High-Fat and High-Sucrose Diet-Induced Adipose Tissue Inflammation by Inhibiting Nuclear Factor-κB Activation.

Obesity-induced inflammation in adipose tissue (AT) promotes the development of metabolic dysregulations by increasing macrophage recruitment in the stromal vascular fraction (SVF). The activation of nuclear factor-κB (NF-κB) signaling in macrophages serves as a pivotal mediator of AT inflammatory responses by increasing the expression of proinflammatory genes in obesity. Given the purported anti-inflammatory effects of berry consumption in humans, we evaluated if anthocyanin-rich aronia berry extract (ARN) can prevent obesity-induced AT inflammation in vivo. We also examined whether ARN suppresses lipopolysaccharide (LPS)-induced NF-κB activation in RAW 264.7 macrophages and mouse bone marrow-derived macrophages (BMDMs). Male C57BL/6J mice were fed a low-fat diet, a high-fat (HF), and high-sucrose (HS) diet or HF/HS diet supplemented with 0.2% ARN (HF/HS + ARN) for 14 weeks. Compared to HF-/HS-fed mice, ARN supplementation tended to decrease fasting serum glucose (P = .07). Furthermore, ARN supplementation significantly inhibited the phosphorylation of NF-κB p65 in epididymal AT with a concomitant decrease in the expression of Cd11b and Tnfα mRNAs in epididymal SVF isolated, compared with those from HF-/HS-fed mice. Consistent with these in vivo findings, ARN treatment significantly decreased the phosphorylation of p65 in LPS-stimulated RAW 264.7 macrophages and BMDMs. Moreover, ARN suppressed LPS-induced mRNA expression of inflammation mediators (iNos, Cox-2, Tnfα, Mcp-1, and Il-6) and glycolysis markers (Glut1, G6pdh, and Hk1) in both cell types. Taken together, our in vivo and in vitro results suggest that ARN supplementation may attenuate obesity-induced AT inflammation by inhibiting NF-κB signaling and glycolytic pathway in macrophages.