Treatment of cigarette smoke extract and condensate differentially potentiates palmitic acid-induced lipotoxicity and steatohepatitis in vitro

Anti-atherogenic role of green tea (Camellia sinensis) in South Indian smokers

ETHNOPHARMACOLOGICAL RELEVANCE

Green tea (Camellia sinensis) is a popular beverage consumed all over the world due to its health benefits. Many of these beneficial effects of green tea are attributed to polyphenols, particularly catechins.

AIM OF THE STUDY

The present study focuses on underlying anti-platelet aggregation, anti-thrombotic, and anti-lipidemic molecular mechanisms of green tea in South Indian smokers.

MATERIALS AND METHODS

We selected 120 South Indian male volunteers for this study to collect the blood and categorised them into four groups; control group individuals (Controls), smokers, healthy control individuals consuming green tea, and smokers consuming green tea. Smokers group subjects have been smoking an average 16-18 cigarettes per day for the last 7 years or more. The subjects (green tea consumed groups) consumed 100 mL of green tea each time, thrice a day for a one-year period.

RESULTS

LC-MS analysis revealed the presence of multiple phytocompounds along with catechins in green tea extract. Increased plasma lipid peroxidation (LPO), protein carbonyls, cholesterol, triglycerides, and LDL-cholesterol with decreased HDL-cholesterol levels were observed in smokers compared to the control group and the consumption of green tea showed beneficial effect. Furthermore, docking studies revealed that natural compounds of green tea had high binding capacity with 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA) when compared to their positive controls, whereas (-) epigallocatechin-3-gallate (EGCG) and (-) epicatechin-gallate (ECG) had high binding capacity with sterol regulatory element-binding transcription factor 1 (SREBP1c). Further, our ex vivo studies showed that green tea extract (GTE) significantly inhibited platelet aggregation and increased thrombolytic activity in a dose dependent manner.

CONCLUSION

In conclusion, in smokers, catechins synergistically lowered oxidative stress, platelet aggregation and modified the aberrant lipid profile. Furthermore, molecular docking studies supported green tea catechins' antihyperlipidemic efficacy through strong inhibitory activity on HMG-CoA reductase and SREBP1c. The mitigating effects of green tea on cardiovascular disease risk factors in smokers that have been reported can be attributed majorly to catechins or to their synergistic effects.

Stevioside Ameliorates Palmitic Acid-Induced Abnormal Glucose Uptake via the PDK4/AMPK/TBC1D1 Pathway in C2C12 Myotubes

BACKGROUND

Stevioside (SV) with minimal calories is widely used as a natural sweetener in beverages due to its high sweetness and safety. However, the effects of SV on glucose uptake and the pyruvate dehydrogenase kinase isoenzyme (PDK4) as an important protein in the regulation of glucose metabolism, remain largely unexplored. In this study, we used C2C12 skeletal muscle cells that was induced by palmitic acid (PA) to assess the effects and mechanisms of SV on glucose uptake and PDK4.

METHODS

The glucose uptake of C2C12 cells was determined by 2-NBDG; expression of the Pdk4 gene was measured by quantitative real-time PCR; and expression of the proteins PDK4, p-AMPK, TBC1D1 and GLUT4 was assessed by Western blotting.

RESULTS

In PA-induced C2C12 myotubes, SV could significantly promote cellular glucose uptake by decreasing PDK4 levels and increasing p-AMPK and TBC1D1 levels. SV could promote the translocation of GLUT4 from the cytoplasm to the cell membrane in cells. Moreover, in Pdk4-overexpressing C2C12 myotubes, SV decreased the level of PDK4 and increased the levels of p-AMPK and TBC1D1.

CONCLUSION

SV was found to ameliorate PA-induced abnormal glucose uptake via the PDK4/AMPK/TBC1D1 pathway in C2C12 myotubes. Although these results warranted further investigation for validation, they may provide some evidence of SV as a safe natural sweetener for its use in sugar-free beverages to prevent and control T2DM.

Effects of solvent extracted organic matter from outdoor air pollution on human type II pneumocytes: Molecular and proteomic analysis

Outdoor air pollution is responsible for the exacerbation of respiratory diseases in humans. Particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) is one of the main components of outdoor air pollution, and solvent extracted organic matter (SEOM) is adsorbed to the main PM2.5 core. Some of the biological effects of black carbon and polycyclic aromatic hydrocarbons, which are components of PM2.5, are known, but the response of respiratory cell lineages to SEOM exposure has not been described until now. The aim of this study was to obtain SEOM from PM2.5 and analyze the molecular and proteomic effects on human type II pneumocytes. PM2.5 was collected from Mexico City in the wildfire season and the SEOM was characterized to be exposed on human type II pneumocytes. The effects were compared with benzo [a] pyrene (B[a]P) and hydrogen peroxide (H2O2). The results showed that SEOM induced a decrease in surfactant and deregulation in the molecular protein and lipid pattern analyzed by reflection-Fourier transform infrared (ATR-FTIR) spectroscopy on human type II pneumocytes after 24 h. The molecular alterations induced by SEOM were not shared by those induced by B[a]P nor H2O2, which highlights specific SEOM effects. In addition, proteomic patterns by quantitative MS analysis revealed a downregulation of 171 proteins and upregulation of 134 proteins analyzed in the STRING database. The deregulation was associated with positive regulation of apoptotic clearance, removal of superoxide radicals, and positive regulation of heterotypic cell-cell adhesion processes, while ATP metabolism, nucleotide process, and cellular metabolism were also affected. Through this study, we conclude that SEOM extracted from PM2.5 exerts alterations in molecular patterns of protein and lipids, surfactant expression, and deregulation of metabolic pathways of type II pneumocytes after 24 h of exposure in absence of cytotoxicity, which warns about apparent SEOM silent effects.

CXCL5 promotes lipotoxicity of hepatocytes through upregulating NLRP3/Caspase-1/IL-1β signaling in Kupffer cells and exacerbates nonalcoholic steatohepatitis in mice

Immune-inflammatory responses play a key role in the development of nonalcoholic steatohepatitis (NASH). Previous studies have demonstrated that CXC motif chemokine ligand 5 (CXCL5) correlates positively with obesity and type 2 diabetes. This study is to explore the functional role of CXCL5 in the pathogenesis of NASH. To establish a NASH model, mice were fed with methionine-and choline-deficient high-fat diet for 6 weeks and anti-CXCL5 mAb was injected during the same period. An in vitro NASH model was established by treating palmitic acid (PA), using a trans-well co-culture system of mouse primary hepatocytes and Kupffer cells (KCs), and recombinant mouse (rm) CXCL5 was treated after PA administration. Our data showed that hepatic CXCL5 levels were highly expressed in the NASH mouse model. CXCL5 neutralization significantly alleviated the severity of NASH livers, demonstrated by pathological analysis, decreased biochemicals, and inflammation. Besides, neutralizing CXCL5 reduced lipid accumulation, cell death, and fibrosis in injured livers. In vitro, rmCXCL5 could not affect the activation of hepatic stellate cells. Also, rmCXCL5 exacerbated PA-induced hepatotoxicity and lipid deposition in hepatocytes co-cultured with KCs rather than in single-cultured hepatocytes. Mechanistically, rmCXCL5 not only promoted NOD-like receptor pyrin domain-containing protein 3 (NLRP3) expression, Cleaved caspase-1 expression, and interleukin 1 beta (IL-1β) secretion in single-cultured and co-cultured KCs but also increased lipid deposition in co-cultured hepatocytes. In addition, MCC950, an inhibitor of NLRP3, almost abolished the effects of rmCXCL5 on PA-treated co-culture system. Therefore, CXCL5 could exacerbate NASH by promoting lipotoxicity of hepatocytes via upregulating NLRP3/Caspase-1/IL-1β signaling in KCs.

Sappanone A ameliorates acetaminophen-induced acute liver injury in mice

Sappanone A (SA), a homoisoflavonoid compound extracted from the heartwood of Caesalpinia sappan Linn., exerts anti-inflammatory and antioxidant activities. However, the effects of SA on acetaminophen (APAP) overdose-induced acute liver injury (ALI) have not been determined yet. This study aims to explore the protective effects of SA and the potential mechanisms of action. Mice were pretreated with SA (25, 50, and 100 mg/kg) by intraperitoneal (i.p.) injection for seven days prior to APAP (300 mg/kg, i.p.) administration. At 12 h after APAP injection, serum and liver samples were collected. Primary murine hepatocytes were used to investigate the underlying mechanisms. SA pretreatment dose-dependently attenuated APAP-induced ALI, as validated by reduced serum alanine/aspartate aminotransferase levels, histopathologic lesions, and oxidative stress. Consistently, pretreatment with SA reduced the formation of APAP protein adducts in damaged livers of mice. Mechanistically, SA could facilitate the nuclear translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) and thus promote cellular glutathione (GSH) synthesis. The hepatoprotective outcomes provided by SA were significantly abolished by treatment with ML385, a Nrf2 inhibitor. Besides, anti-inflammatory property of SA reduced inflammatory reaction in injured livers of mice. Of note, posttreatment with SA reveals significant therapeutic influences against APAP-induced ALI in mice. Collectively, our findings demonstrated that pretreated-SA ameliorated APAP-mediated ALI in mice, at least in part, by reducing the generation of APAP protein adducts via Nrf2-enhanced GSH synthesis, and by diminishing hepatic inflammation. Therefore, SA could be a potential hepatoprotective agent for treating ALI.

Metabolomics-based safety evaluation of acute exposure to electronic cigarettes in mice

INTRODUCTION

A growing number of epidemiological evidence reveals that electronic cigarettes (E-cigs) were associated with pneumonia, hypertension and atherosclerosis, but the toxicological evaluation and mechanism of E-cigs were largely unknown.

OBJECTIVE

Our study was aimed to explore the adverse effects on organs and metabolomics changes in C57BL/6J mice after acute exposure to E-cigs.

METHODS AND RESULTS

Hematoxylin and eosin (H&E) staining found pathological changes in tissues after acute exposure to E-cigs, such as inflammatory cell infiltration, nuclear pyknosis, and intercellular interstitial enlargement. E-cigs could increase apoptosis-positive cells in a time-dependent way using Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. Oxidative damage indicators of reactive oxygen species (ROS), malondialdehyde (MDA) and 4-hydroxynonena (4-HNE) were also elevated after E-cigs exposure. There was an increasing trend of total glycerol and cholesterol in serum, while the glucose and liver enzymes including alanine aminotransferase (ALT), aspartate transaminase (AST), gamma-glutamyltranspeptidase (γ-GT) had no significant change compared to that of control. Further, Q Exactive high field (HF) mass spectrometer was used to conduct metabolomics, which revealed that differential metabolites including l-carnitine, Capryloyl glycine, etc. Trend analysis showed the type of compounds that change over time. Pathway enrichment analysis indicated that E-cigs affected 24 metabolic pathways, which were mainly regulated amino acid metabolism, further affected the tricarboxylic acid (TCA) cycle. Additionally, metabolites-diseases network analysis found that the type 2 diabetes mellitus, propionic acidemia, defect in long-chain fatty acids transport and lung cancer may be related to E-cigs exposure.

CONCLUSIONS

Our findings provided important clues for metabolites biomarkers of E-cigs acute exposure and are beneficial for disease prevention.

Oral administration of Jinan Red Ginseng and licorice extract mixtures ameliorates nonalcoholic steatohepatitis by modulating lipogenesis

Background

Nonalcoholic steatohepatitis (NASH) is one of the main chronic liver diseases. NASH is identified by lipid accumulation, inflammation, and fibrosis. Jinan Red Ginseng (JRG) and licorice have been widely used because of their anti-inflammatory and hepatoprotective effects. Hence, this study assessed JRG and licorice extract mixtures' effects on NASH progression.

Methods

Palmitic acid (PA) and the western diet (WD) plus, high glucose-fructose water were used to induce in vitro and in vivo NASH. Mice were orally administered with JRG-single (JRG-S) and JRG-mixtures (JRG-M; JRG-S + licorice) at 0, 50, 100, 200 or 400 mg/kg/day once a day during the last half-period of diet feeding.

Results

JRG-S and JRG-M reduced NASH-related pathologies in WD-fed mice. JRG-S and JRG-M consistently decreased the mRNA level of genes related with inflammation, fibrosis, and lipid metabolism. The treatment of JRG-S and JRG-M also diminished the SREBP-1c protein levels and the p-AMPK/AMPK ratio. The FAS protein levels were decreased by JRG-M treatment both in vivo and in vitro but not JRG-S.

Conclusion

JRG-M effectively reduced lipogenesis by modulating AMPK downstream signaling. Our findings suggest that this mixture can be used as a prophylactic or therapeutic alternative for the remedy of NASH.

Cigarette smoke alters inflammatory genes and the extracellular matrix - investigations on viable sections of peripheral human lungs

Chronic obstructive pulmonary disease (COPD) is a complex chronic respiratory disorder often caused by cigarette smoke. Cigarette smoke contains hundreds of toxic substances. In our study, we wanted to identify initial mechanisms of cigarette smoke induced changes in the distal lung. Viable slices of human lungs were exposed 24 h to cigarette smoke condensate, and the dose–response profile was analyzed. Non-toxic condensate concentrations and lipopolysaccharide were used for further experiments. COPD-related protein and gene expression was measured. Cigarette smoke condensate did not induce pro-inflammatory cytokines and most inflammation-associated genes. In contrast, lipopolysaccharide significantly induced IL-1α, IL-1β, TNF-α and IL-8 (proteins) and IL1B, IL6, and TNF (genes). Interestingly, cigarette smoke condensate induced metabolism- and extracellular matrix–associated proteins and genes, which were not influenced by lipopolysaccharide. Also, a significant regulation of CYP1A1 and CYP1B1, as well as MMP9 and MMP9/TIMP1 ratio, was observed which resembles typical findings in COPD. In conclusion, our data show that cigarette smoke and lipopolysaccharide induce significant responses in human lung tissue ex vivo, giving first hints that COPD starts early in smoking history.

Exogenous activation of toll-like receptor 5 signaling mitigates acetaminophen-induced hepatotoxicity in mice

Acetaminophen (APAP) poisoning is the most common cause of drug-induced acute liver injury (ALI). Our results showed that toll-like receptor 5 (TLR5) was abundantly expressed in hepatocytes and dramatically downregulated in the toxic mouse livers. Hence, we herein investigated the role of TLR5 signaling after APAP overdose. Mice were intraperitoneally (i.p.) injected with APAP to induce ALI, and then injected with flagellin at one hour after APAP administration. Flagellin attenuated APAP-induced ALI based on decreased histopathologic lesions, serum biochemical, oxidative stress, and inflammation. Furthermore, the protective effects of flagellin were abolished by TH1020 (a TLR5 antagonist) treatment. These results suggest that flagellin exerted protective effects on ALI via TLR5 activation. Mechanistically, flagellin injection promoted the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2) to the nucleus in hepatocytes. Consistent with the in vivo results, flagellin increased the activation of Nrf2 in hepatocytes, resulting in decreased APAP toxicity. ML385, a selective inhibitor of Nrf2, abolished the flagellin-mediated hepatoprotective effects in damaged livers and hepatocytes. Additionally, the flagellin-induced Nrf2 translocation was dependent upon the activation of TLR5-JNK/p38 pathways. These findings suggest that TLR5 signaling-induced Nrf2 activation, at least partially, contributed to the protection against APAP-induced ALI by flagellin treatment.

Dual TBK1/IKKε inhibitor amlexanox mitigates palmitic acid-induced hepatotoxicity and lipoapoptosis in vitro

The common causes of Non-alcoholic fatty liver disease (NAFLD) are obesity, dyslipidemia, and insulin resistance. Metabolic disorders and lipotoxic hepatocyte damage are hallmarks of NAFLD. Even though amlexanox, a dual inhibitor of TRAF associated nuclear factor κB (NF-κB) activator-binding kinase 1 (TBK1) and IκB kinase epsilon (IKKε), has been reported to effectively improve obesity-related metabolic dysfunctions in mice models, its molecular mechanism has not been fully investigated. This study was designed to investigate the effects of amlexanox on in vitro nonalcoholic steatohepatitis (NASH) model induced by treatment of palmitic acid (PA, 0.4 mM), using a trans-well co-culture system of hepatocytes and Kupffer cells (KCs). Stimulation with PA significantly increased the phosphorylation levels of TBK1 and IKKε in both hepatocytes and KCs, suggesting a potential role of TBK1/IKKε in PA-induced NASH progression. Treatment of amlexanox (50 μM) showed significantly reduced phosphorylation of TBK1 and IKKε and hepatotoxicity as confirmed by decreased levels of lactate dehydrogenase released from hepatocytes. Furthermore, PA-induced inflammation and lipotoxic cell death in hepatocytes were significantly reversed by amlexanox treatment. Intriguingly, amlexanox inhibited the activation of KCs and induced polarization of KCs towards M2 phenotype. Mechanistically, amlexanox treatment decreased the phosphorylation of interferon regulator factor 3 (IRF3) and NF-κB in PA-treated hepatocytes. However, decreased phosphorylation of NF-κB, not IRF3, was found in PA-treated KCs upon amlexanox treatment. Taken together, our findings show that treatment of amlexanox attenuated the severity of PA-induced hepatotoxicity in vitro and lipoapoptosis by the inhibition of TBK1/IKKε-NF-κB and/or IRF3 pathway in hepatocytes and KCs.

AK-1, a Sirt2 inhibitor, alleviates carbon tetrachloride-induced hepatotoxicity in vivo and in vitro

Background/Aim: Acute liver injury (ALI) is a life-threatening clinical syndrome that is usually caused by toxic chemicals, drugs, or pathogen infections. Sirtuin2 (Sirt2), an NAD⁺-dependent deacetylase, appears to play detrimental roles in liver injury. Here, we evaluated the therapeutic application targeting Sirt2 in carbon tetrachloride (CCl₄)-induced ALI, by using AK-1 (a Sirt2 inhibitor).Methods: For in vivo experiments, a single injection of CCl₄ was used to induce ALI. One hour later, mice were intraperitoneally injected with AK-1 and were sacrificed 24 h after CCl₄ administration. For in vitro experiments, primary mouse hepatocytes were used to determine the effects of AK-1 on oxidative stress and hepatocellular death induced by CCl₄.Results: AK-1 alleviated CCl₄-induced ALI as confirmed by histopathologic analysis, and decreased levels of serum biochemicals and inflammatory cytokines. Although it barely affected the expression of hepatic cytochrome P450 enzymes, AK-1 attenuated CCl₄-induced oxidative stress and its related cell death. Mechanistically, Sirt2 inhibition significantly increased the nuclear protein level of nuclear factor erythroid 2-related factor 2 (Nrf2), and meanwhile decreased phosphorylation of c-Jun N-terminal kinases (JNK), in normal and injured livers. Similar results were observed in vitro. AK-1 significantly attenuated CCl₄-induced cytotoxicity and oxidative stress by up-regulating the activity of Nrf2, and down-regulating JNK signaling in hepatocytes.Conclusions: Our results suggest that AK-1 treatment attenuated oxidative stress and cell death in the ALI model, at least partially, via activating Nrf2 and inhibiting JNK signaling, and that Sirt2 inhibition might be a potential approach to cure ALI.

Developmental changes in hepatic lipid metabolism of chicks during the embryonic periods and the first week of posthatch

The liver is the main site of de novo lipogenesis in poultry, and hepatic lipid metabolism disorder will lead to excessive abdominal fat deposition or fatty liver disease, finally causing huge economic loss. The present study was conducted to investigate developmental changes in hepatic lipid metabolism of chicks from embryonic periods to the first week after hatching. Liver samples were collected from embryonic day 11 (E11) to the age of day 7 posthatch (D7) for lipid metabolism analysis. Hematoxylin–eosin and Oil Red O staining analysis showed that hepatic lipids increased gradually during embryonic period and declined posthatch; The sum of hepatic triglycerides and cholesterol reached the peak at E19 and D1 by ELISA analysis (P < 0.05). Acetyl-CoA carboxylase, fatty acid synthase, and acyl-CoA desaturase 1 mRNA expression in the liver were higher from E17 to D1 with the peak at E19 when compared with those at E13 and E15 (P < 0.05). Hepatic elongase of very long-chain fatty acids 6 and microsomal triglyceride transfer protein mRNA abundance were lower during embryonic periods but reached relative higher level after hatching (P < 0.05). On the contrary, hepatic carbohydrate response element binding protein (ChREBP), carnitine palmitoyltransferase 1, and peroxisome proliferators–activated receptor α expression were higher during embryonic periods but decreased posthatch (P < 0.05). The mRNA abundance of sterol-regulatory element binding protein 1c was the lowest at E13 and E15, then increased gradually from E17 to D1, while decreased from D3 to D7 little by little (P < 0.05). In summary, hepatic lipogenesis genes have different expression patterns during the embryonic periods and the first week of posthatch, which might be activated by ChREBP during embryonic periods; fatty acid oxidation was enhanced around the hatched day but declined posthatch. These findings will broaden the understanding of physiological characteristics and dynamic pattern about hepatic lipid metabolism in chicks.

Toll-Like Receptor 5 Signaling Ameliorates Liver Fibrosis by Inducing Interferon β-Modulated IL-1 Receptor Antagonist in Mice

Bacterial flagellin, recognized by cell surface of Toll-like receptor (TLR) 5, is a potent activator of many types of cells, leading to the activation of innate or adaptive immunity, which are pivotal in regulating fibrotic process. However, the exact role of TLR5 signaling in hepatic fibrogenesis remains unclear, and this study aims to elucidate its underlying mechanisms. Flagellin was injected to hepatotoxin- and cholestasis-induced liver fibrosis murine models. Flagellin-induced TLR5 activation significantly decreased the severity of liver fibrosis. Interestingly, the expression levels of IL-1 receptor antagonist (IL1RN) and interferon (IFN)β markedly increased in fibrotic livers on flagellin treatment. Consistently, in vivo activation of TLR5 signaling markedly increased IFNβ and IL1RN expression in the livers. Notably, flagellin injection significantly exacerbated the severity of liver fibrosis in IFN-α/β receptor 1 (IFNAR1) knockout mice. Furthermore, hepatic expression of IL1RN in the fibrotic livers of IFNAR1 knockout mice was significantly lower than those of wild-type mice. In support of these findings, flagellin-mediated IL1RN production is not sufficient to alleviate the severity of hepatic fibroinflammatory responses in IFNAR1-deficient milieu. Finally, hepatic stellate cells treated with IL1RN had significantly decreased cellular activation and its associated fibrogenic responses. Collectively, manipulation of TLR5 signaling may be a promising therapeutic strategy for the treatment of liver fibrosis.

Dual TBK1/IKKɛ inhibitor amlexanox attenuates the severity of hepatotoxin-induced liver fibrosis and biliary fibrosis in mice

Although numerous studies have suggested that canonical IκB kinases (IKK) play a key role in the progression of liver fibrosis, the role of non-canonical IKKε and TANK-binding kinase 1 (TBK1) on the development and progression of liver fibrosis remains unclear. To demonstrate such issue, repeated injection of CCl4 was used to induce hepatotoxin-mediated chronic liver injury and biliary fibrosis was induced by 0.1% diethoxycarbonyl-1, 4-dihydrocollidine diet feeding for 4 weeks. Mice were orally administered with amlexanox (25, 50, and 100 mg/kg) during experimental period. Significantly increased levels of TBK1 and IKKε were observed in fibrotic livers or hepatic stellate cells (HSCs) isolated from fibrotic livers. Interestingly, amlexanox treatment significantly inhibited the phosphorylation of TBK1 and IKKε accompanied by reduced liver injury as confirmed by histopathologic analysis, decreased serum biochemical levels and fibro-inflammatory responses. Additionally, treatment of amlexanox promoted the fibrosis resolution. In accordance with these findings, amlexanox treatment suppressed HSC activation and its related fibrogenic responses by partially inhibiting signal transducer and activator of transcription 3. Furthermore, amlexanox decreased the activation and inflammatory responses in Kupffer cells. Collectively, we found that inhibition of the TBK1 and IKKε by amlexanox is a promising therapeutic strategy to cure liver fibrosis.

Cigarette smoking differentially regulates inflammatory responses in a mouse model of nonalcoholic steatohepatitis depending on exposure time point

Cigarette smoke (CS) is a risk factor for the development of nonalcoholic fatty liver disease. However, the role of mainstream CS (MSCS) in the pathogenesis of nonalcoholic steatohepatitis (NASH) remains unclear. During the first (early exposure) or last (late exposure) three weeks of methionine-choline deficient with high fat diet feeding (6 weeks), each diet group was exposed to MSCS (300 or 600 μg/L). Hepatic or serum biochemical analysis showed that MSCS differentially modulated hepatic injury in NASH milieu, depending on exposure time points. Consistently, NASH-related hepatocellular apoptosis and fibrosis were increased in the early exposure group, but decreased in the late exposure group, except for steatosis. Ex vivo experiments showed that CS extract differentially regulated inflammatory responses in co-cultured hepatocytes and macrophages isolated from steatohepatitic livers after 10 days or 3 weeks of diet feeding. Furthermore, CS differentially up- and down-regulated the expression levels of M1/M2 polarization markers and peroxisome proliferator-activated receptor-gamma (PPARγ) in livers (29% and 38%, respectively) or co-cultured macrophages (2 and 2.5 fold, respectively). Collectively, our findings indicate that opposite effects of MSCS on NASH progression are mediated by differential modulation of PPARγ and its-associated M1/M2 polarization in hepatic macrophages, depending on exposure time points.