Amelioration of Alcoholic Liver Steatosis by Dihydroquercetin through

J. Agric. Food Chem. , Article ASAP. DOI: 10.1021/acs.jafc.8b00944. Publication Date (Web): April 28, 2018. Copyright © 2018 American Chemical Societ...
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Bioactive Constituents, Metabolites, and Functions

Modulation of AMPK-dependent lipogenesis mediated by P2x7R-NLRP3 inflammasome activation contributes to the amelioration of alcoholic liver steatosis by dihydroquercetin Yu Zhang, Quan Jin, Xia Li, Jiang Min, Ben-Wen Cui, Kai-Li Xia, Yan-Ling Wu, Li-Hua Lian, and ji-xing nan J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.8b00944 • Publication Date (Web): 28 Apr 2018 Downloaded from http://pubs.acs.org on April 28, 2018

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Graphical abstract 220x225mm (300 x 300 DPI)

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of

AMPK-dependent

lipogenesis

mediated

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Modulation

by

P2x7R-NLRP3

2

inflammasome activation contributes to the amelioration of alcoholic liver steatosis

3

by dihydroquercetin

4

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Running title: Dihydroquercetin alleviates alcoholic liver steatosis

6

7

Yu Zhanga†, Quan Jin†a, Xia Lia, Min Jianga, Ben-Wen Cuia, Kai-Li Xiaa, Yan-Ling Wua,

8

Li-Hua Liana*, Ji-Xing Nan*a,b

9

10

a

Key Laboratory for Natural Resource of Changbai Mountain & Functional

11

Molecules, Ministry of Education, College of Pharmacy, Yanbi

12

Jilin Province 133002, China

13 14

15

b

an University, Yanji,

Clinical Research Center, Yanbian University Hospital, Yanji, Jilin Province

133002, China

†These authors contributed equally to this work.

16

*Corresponding to

17

Li-Hua Lian, Ji-Xing Nan, Key Laboratory for Natural Resource of Changbai Mountain

18

& Functional Molecules, Ministry of Education, College of Pharmacy, Yanbian 1

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University, Yanji 133002 Jilin Province, China, Tel.: 86-433-2435061, fax:

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86-433-2435072. E-mail address: [email protected] (L.-H. Lian), [email protected]

21

(J.-X. Nan).

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ABSTRACT

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Dihydroquercetin (TAX) is the most abundant dihydroflavone found in onions, milk

24

thistle and Douglas fir bark. We investigated whether TAX could inhibit the lipid

25

accumulation in alcoholic liver steatosis in vivo and in vitro. An in vivo model was

26

established by intragastrically treating mice with ethanol, and an in vitro model was

27

created by treating HepG2 cells with ethanol. TAX regulated SREBP1 and ACC

28

expression via elevating LKB1/AMPK phosphorylation. Also, TAX upregulated SIRT1

29

expression, which suppressed by ethanal intake. Decreased expression of P2x7R and

30

NLRP3 and suppressed cleavage of caspase-1 by TAX resulted in the inhibition of

31

IL-1β production and release. Additionally, TAX reduced lipogenesis and promoted

32

lipid oxidation via the regulation of AMPK and ACC in ethanol-treated steatotic

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HepG2 cell. TAX downregulated IL-1β cleavage response to LPS plus ATP stimulation

34

in HepG2 cells. P2x7R deficiency attenuated lipid accumulation characterized by the

35

increased AMPK activity and decreased SREBP1 expression in ethanol-treated HepG2

36

cells. Our data showed that TAX exhibited the inhibitory properties on lipogenesis

37

and hepatoprotective capacity, indicating that TAX has therapeutic potential for

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preventing alcoholic liver steatosis.

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Keywords: alcoholic liver steatosis; AMPK; dihydroquercetin; NLRP3; P2x7R

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INTRODUCTION

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Acute alcoholic fatty liver refers to alcoholic liver disease (ALD) caused by

43

excessive intake of alcohol. Liver steatosis, liver cell damage and inflammatory cell

44

infiltration are frequently associated with acute alcoholic fatty liver. If drinking

45

continues, acute alcoholic fatty liver will develop to liver fibrosis, cirrhosis, or even

46

cancer. Severe drinking can cause extensive liver cell necrosis and even hepatic

47

failure 1. ALD brings huge damage to the human health and gives rise to significant

48

morbidity and mortality 2. Unfortunately, there is still no effective medical treatment

49

for any stage of ALD in the past few decades.

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Acute alcoholic liver steatosis is characterized by lipid accumulation in

51

hepatocytes 3. Alcohol mediated liver steatosis involves many regulatory factors, such

52

as AMP dependent AMP-activated kinase (AMPK). AMPK, as a lipid regulating kinase,

53

plays an important regulatory role in the pathogenesis of alcoholic liver steatosis 4.

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Activated AMPK promotes the phosphorylation of acetyl-CoA carboxylase (ACC),

55

inhibits the activity of ACC and results in the regulation of the fatty acids synthesis

56

and fatty acid oxidation. As an upstream kinase of AMPK, liver kinase B1 (LKB1) can

57

activate AMPK. Direct phosphorylation of AMPK also inhibits the activity of Sterol

58

regulatory element-binding protein 1 (SREBP1) in hepatocytes and thereby reduces

59

lipid deposition 5. Alcohol exposure can upregulate SREBP1 and increase fatty acid

60

synthesis in hepatocytes 6. Sirtuin 1 (SIRT1) plays an important role in the regulation

61

of lipid metabolism and inflammation. Alcohol can affect the SIRT1 signaling pathway

4

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in the pathogenesis of alcoholic liver steatosis 7, 8 . Alcohol downregulates SIRT1 level

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leading to liver lipid accumulation and inflammatory response.

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Inflammation plays a crucial role in the underlying pathogenesis of ALD 9.

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Alcohol-induced increased gut permeability lead to increased lipopolysaccharides

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(LPS) level in the circulation 9. Gut microflora-derived LPS is recognized by toll-like

67

receptor 4 (TLR4) and provides the first signal for inflammasome activation

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Ethanal exposure increased circulating and liver adenosine triphosphate (ATP) levels,

69

indicating ATP signaling is involved in liver inflammation in ALD 11. An ATP-gated ion

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channel, purinergic 2X7 receptor (P2x7R) is critical for inflammasome activation. High

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levels of ATP, as a second signal in LPS-driven inflammation, results in the

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downregulation of nod-like receptor pyrin containing 3 (NLRP3) inflammasome

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activation and inflammatory mediators release. NLRP3 inflammasome activation

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leads to the release of proinflammatory cytokines, such as interleukin (IL)-1β.

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Regulation of P2x7R-NLRP3 inflammasome activation by small molecule is a

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promising target to treat alcoholic liver steatosis 12. Although many researchers have

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made extensive and profound studies on ALD, the precise pathogenesis responsible

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for ALD are still not clear. Worse yet, there are no effective treatments for ALD.

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Therefore, a safe and effective approach for therapy of ALD is urgently needed.

10

.

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Flavonoids are a large family of components widely existed in most traditional

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Chinese herbal medicines. Dihydroquercetin (also called taxifolin, TAX, Fig 1A), is the

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most abundant dihydroflavone found in onions 13, milk thistle 14 and Douglas fir bark

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(Pseudotsuga taxifolia)

. TAX has been widely used in in food and healthcare

84

industry as food additives. Several studies showed that TAX possesses various

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pharmacological activities, such as anti-virus 16, anti-inflammatory 17, anti-oxidant 18,

86

19

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anti-oxidative capacities of TAX. TAX showed potent inhibitory properties on

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lipogenesis in prostate and breast cancer cells by inhibiting fatty acid synthase

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enzymes

90

silymarin (Legalon®) used in the phytotherapy and dietary supplement for chronic

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hepatitis and alcoholics fatty liver

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hepatoprotective mechanisms of the hepatoprotective flavonolignans from the

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silymarin compound, including TAX. However, research on TAX in the

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hepatoprotective properties is minimal. Considering the inhibitory properties on

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lipogenesis and hepatoprotective capacity, we anticipate the possible beneficial

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effects of TAX on liver lipid accumulation and inflammation induced by alcohol.

and anti-fibrosis 20. By far accumulating evidence has been surrounding the potent

21

. TAX is the only flavonoid found in the licensed hepatoprotective drug

15

. Polyak et al

16

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MATERIALS AND METHOD

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Reagents and materials. TAX (Pubchem CID: 439533; purity ≥ 99.00%) was purchased

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from Chengdu Push Bio-technology Co., Ltd. Anti-AMPKα, anti-phospho-AMPKα,

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anti-LKB1, anti-phospho-LKB1, anti-ACC, and anti-phospho-ACC antibodies were

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purchased from Cell Signaling Technology (Beverly, MA, USA). Anti-SIRT1,

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anti-SREBP1,

104

dehydrogenase (GAPDH) antibodies and A438079 (PubChem CID: 11673921) were

105

purchased from Abcam (Cambridge, MA, USA). Anti-Caspase-1 antibody and

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Caspase-1 inhibitor VI (Z-YVAD-FMK, PubChem CID: 16760349) were obtained from

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Santa Cruz Biotechnology, Inc. (Santa Cruz, CA, USA). Anti-IL-1β antibody was

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purchased from R&D Systems (Minneapolis, MN, USA). Ultrapure lipopolysaccharides

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from E. coli O111:B4 and TLR4 inhibitor (CLI-095) were purchased from InvivoGen

110

(San Diego, CA, USA), and adenosine 5′-triphosphate disodium salt was purchased

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from Sigma Chemical Co. (St. Louis, MO, USA). Metformin, a LKB1/AMPK activator 22,

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23

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Biotechnology (Haiman, Jiangsu, China).

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Animals experimental protocols. Male C57BL/6 mice (8-10 weeks old, 20-22g) were

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purchased from Changchun Yisi Laboratory Animal Technology Co., Ltd ([SPF, SCXK (JI)

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2011-0004], Changchun, Jilin, China). All animals were housed in a 12/12 h light/dark

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environment with a consist temperature 22 ± 2°C and humidity 55±5%. All

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procedures throughout the animal experiments were carried out strictly to follow

Anti-P2x7R,

Anti-NLRP3

and

anti-glyceraldehyde-3-phosphate

, used as positive control and was purchased from Beyotime Institute of

7

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Guide for the Care and Use of Laboratory Animals (National Research Council, 1996)

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and approved by Animal Research Committee of Yanbian University.

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After a week of acclimatization, all animals were randomly assigned to six

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groups, as follows: normal group, ethanol group, ethanol plus TAX groups (1, 5, 25

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mg/kg, body weight) and TAX only group. Mice in normal groups were treated with

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an isocalorical maltose solution. Mice were exposed to acute alcohol treatment

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according to the previously published protocols

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were gavaged with ethanol at a dose of 5 g/Kg (body weight) every 12 h for 3 times.

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And TAX was intragastrically treated simultaneously with ethanol to the mice. Four

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hours after the last administration of ethanol, all mice were sacrificed under

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anesthetization by isoflurane. Blood was collected by direct cardiac puncture. The

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mice liver was removed, and a portion of liver was fixed in 10% neutral buffered

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formalin for histological analysis. The rest tissues were stored at -80 °C until

132

analyzed.

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Cell culture. The Human Hepatoma Cell Line HepG2 were kindly provided by Dr. Jung

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Joon Lee (Korea Institute of biological sciences and Biotechnology, Daejeon, South

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Korea). HepG2 were cultured in DMEM supplemented with 10% fetal bovine serum

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(FBS), 100 μg/ml streptomycin and 100 units/ml penicillin, in a 37 ℃ humidified

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incubator with 5% CO2. HepG2 cells were exposed with ethanol (50mM) for 24 h or

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primed with LPS (1 μg/ml) for 4 h then continuously stimulated ATP (3 mM) for

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additional 30 min. TAX or appropriate inhibitors was pretreated 1 h prior to LPS

24, 25

. All mice except normal group

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treatment or ethanol exposure.

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Liver histological analysis. For HE and Oil Red O staining, liver tissues fixed with 10%

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neutral buffered formalin were embedded in paraffin. 5-μm-thick sections were

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stained with HE or oil red O.

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Measurement of biochemical parameters. Blood samples were centrifuged at 3000

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rpm and 4℃ for 30 min to collect serum and then stored at -80℃ for further

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measurement. The levels of serum alanine aminotransferase (ALT) and aspartate

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aminotransferase (AST) were detected by an Automatic biochemical analyzer

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(Spotchem SP4430, Arkray, Kyoto, Japan). Serum and Hepatic triglycerides (TG) levels

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were determined using commercial quantification assay kits (Nanjing Jiancheng

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Bioengineering Institute, Nanjing, Jiangsu, China) according to the manufacturer’s

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protocols.

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Enzyme-linked immunosorbent assay (ELISA). Mouse IL-1β and lipopolysaccharide

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(LPS)-Binding Protein (LBP) protein levels in serum were measured using murine

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IL-1β Standard ABTS ELISA Development Kit (PeproTech, Rocky Hill, NJ, USA) or

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mouse lipopolysaccharide-binding protein (LBP) ELISA kit (Cusabio Biotech Co., Ltd,

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Wuhan, Hubei, China) according to the manufacturers' instruction.

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ATP assay

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Serum ATP levels were determined using Enhanced ATP Assay Kit (Beyotime Institute

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of Biotechnology, Haiman, Jiangsu, China) with luminometer. 9

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Immunohistochemistry and immunocytochemistry staining. Paraffin sections of

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mice liver were deparaffinized in xylene and passed through sequential decreasing

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concentrations of ethanol. Sections were microwaved in 10 mM sodium citrate buffer

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(pH 6.0), and then allowed to cool back to room temperature. Slides were treated

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with 3% hydrogen peroxide, followed by blocking with 5% normal goat serum and

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Avidin/Biotin Blocking solution (Vector Laboratories, Inc., Burlingame, CA, USA).

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Immunohistochemical staining was performed using prediluted mouse anti-SREBP1,

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anti-SIRT1, anti-NLRP3 or anti-P2x7R antibodies. The sections were then incubated

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with appropriate secondary antibodies. Bound antibodies were visualized with Lab

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Vision™ DAB Plus Substrate Staining System (Thermo Fisher Scientific, Fremont, CA,

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USA) and then images were acquired by a light microscopy (Nikon TI-E, Nikon, Tokyo,

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Japan). HepG2 cells were grown on coverslips in 6-well plates and then treated with

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TAX. Cells were fixed with 4% paraformaldehyde and then performed as previously

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described 26. Stained cells were visualized by a Nikon TI-E fluorescence microscope.

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All these examinations were carried out in a blinded manner.

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Small interference RNA (siRNA) transfection. HepG2 cells were transfected with

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scrambled control siRNA or P2x7R-siRNA (Bioneer, Shanghai, China) using

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Lipofectamine® RNAiMAX reagent (Thermo Fisher Scientific Inc., Waltham, MA, USA).

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The transfection efficiency of FAM-labeled negative control siRNA was >90% after 24

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h

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5′-AGAGCAAAGUGACCUGGUU-3′; antisense, 5′-AACCAGGUCACUUUGCUCU-3′.

transfection.

Sequences

for

human

P2x7R-siRNA

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sense,

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Western blot analysis. Total protein or nuclear protein was extracted from livers or

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HepG2 cells with lysis buffer or Nuclear and Cytoplasmic Protein Extraction Kit

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(Beyotime Institute of Biotechnology). Equal amounts of protein were separated by

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8–12% sodium dodecyl sulphase-polyacrylamide gel electrophoresis (SDS-PAGE), and

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then transferred to PVDF membranes. And membranes were blocked 5% skim milk in

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PBS containing 0.05% Tween 20, and then incubated with specific primary antibody,

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followed by the incubation with an HRP-conjugated secondary antibody. Finally

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target protein was visualized using Clarity™ ECL Western Blotting Substrate (Bio-Rad,

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Hercules, CA, USA), and quantified densitometry with Bio-Rad Quantity One

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software.

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Statistical analysis. Results are expressed as the mean ± SD. All data were followed a

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Gaussian distribution (p>0.1) analyzed by Kolmogorov–Smirnov normality tests. For

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animal and cell studies, statistical significance was determined using one-way

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analysis of variance (ANOVA) and Tukey multiple comparisons. A statistically

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significant between groups (P value) is less than 0.05. Statistical analyses were

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performed using the GraphPad Prism v6 (Graphpad Software Inc., San Diego, CA,

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USA).

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RESULTS

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TAX attenuates ethanol-induced lipid accumulation in mice liver. After alcohol

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exposure,

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alcohol-administrated group than in normal group (Fig 1B). The TG contents in serum

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and liver were determined by biochemical analysis. The increase of serum and

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hepatic TG accumulation was observed in alcohol-administrated group, compared

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with normal group (Fig 1C). TAX co-administration led to a significant decrease of

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serum ALT and AST in alcohol-administrated group. A remarkable reduction of TG

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level in serum and liver was also observed with TAX co-administration in

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alcohol-administrated mice. Decreased serum aminotransferase and TG level hinted

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that TAX has a potent hepatoprotective capacity against alcohol treatment.

serum

AST

and

ALT

levels

were

significantly

higher

in

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To further evaluate liver histological changes, the liver sections were stained by

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H&E or Oil-red O. Hepatocellular ballooning and accumulation of lipid droplets were

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observed in mice livers after alcohol intake (Fig 1D and 1E). TAX treatment notably

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reduced the degree of lipid accumulation, suggesting TAX could regulate

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alcohol-induced liver steatosis.

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In alcohol-fed mice, serum ATP level was elevated, indicating high levels of ATP

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in ALD progression might be acted as a danger signal, which was consistent with

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previous studies 27. And TAX pretreatment suppressed circulating ATP level (Fig 1F).

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LBP forms a complex with LPS and then that complex bound to membrane

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TLR4/CD14 28. Because LBP is released into circulation response to LPS, LBP level in 12

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circulation can be considered as a surrogate biomarker of LPS-induced response29.

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The serum LBP level in alcohol-exposed mice notably elevated compared with normal

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mice and this increase was significantly abolished by TAX (Fig 1G).

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TAX regulates lipid metabolism by activating AMPK in alcohol-induced liver

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steatosis. To clarify the underlying mechanism of reduced lipid accumulation in

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TAX-pretreated mice exposed to ethanol, we determined the expression of proteins

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involved in lipid metabolism, including lipid synthesis and β-oxidation. AMPK and its

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upstream kinase-LKB1 regulates lipid metabolism. As shown in Fig 2A, the protein

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levels of total and phosphorylated LKB1 and AMPK were downregulated under

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ethanol exposure. Inhibitory effect of AMPK and LKB1 phosphorylation caused by

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alcohol was improved by TAX treatment more than 176% and 144% compared with

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that of the mice liver treated ethanol. The SREBP1, which regulates lipid biosynthesis,

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are synthesized as precursors of 125 kDa and active mature nuclear forms (~68 kDa)

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30

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increased in nuclear fraction protein of mice liver (Fig 2A). And the increase of

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SREBP1

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immunohistological staining for SREBP1 (Fig 2C). With TAX pretreatment SREBP1

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expression was descended in alcoholic fatty mice liver (Fig 2A and 2C). ACC is a key

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enzyme, regulating synthesis and β-oxidation of lipid 31. And the protein expression

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of phosphorylated ACC was decreased, accompanied with increased ACC expression,

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while TAX abolished the inhibition of phosphorylated ACC induced by ethanol (Fig

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2A). SIRT1 functions as upstream regulators of LKB1-AMPK axis 32. Ethanol exposure

. Also consumed with binge alcohol, mature forms of SREBP1 were significantly

in

the

alcohol-induced

steatotic

liver

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also

detected

by

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downregulated protein expression of SIRT1 confirmed by western blot and

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immunohistochemistry staining for SIRT1 (Fig 2A and 2D). As expected, TAX

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successfully evoked SIRT1 activity by 1.26-fold in alcoholic steatotic mice livers,

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compared with that of the mice liver treated ethanol. It indicated that TAX might

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suppress lipid accumulation in alcoholic steatotic liver likely through inhibiting lipid

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synthesis and promoting lipid oxidation.

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TAX

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inflammasome in mice liver. IL-1β signaling mediates steatosis, and is associated

250

with NLRP3 inflammasome activation

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ethanol exposure was suppressed after TAX administration, with 261% decrease than

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alcoholic steatotic mice (Fig 3A). TAX treatment also showed decreased tendency of

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NLRP3 protein expression and caspase-1 cleavage, determined by western blotting

254

and immunohistochemistry stain (Fig 3B and 3D). Our data indicated that TAX could

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inhibit the inflammasome activation after ethanol exposure. There results prompted

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us to investigate whether P2x7R activation will be blocked by TAX. We observed that

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protein expression of P2x7R was remarkably decreased by TAX in mice livers with

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alcoholic liver steatosis (Fig 3B and 3E).

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TAX alleviates lipid accumulation induced by ethanol in hepatocytes. In order to

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focus on the lipid accumulation in hepatocytes, we applied HepG2 cells, which

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express ADH4 metabolizing ethanol 34. Droplets in ethanol-treated HepG2 cells were

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obviously red stained with oil red O, while TAX concentration-dependently

inhibits

ethanol-induced

inflammatory

33

response

via

P2x7R-NLRP3

. The increased secretion of IL-1β after

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suppressed lipid droplets accumulation in HepG2 cells (Fig 4A). Exposure of HepG2

264

cells to ethanol let to a significant decrease of protein expression of phosphorylated-

265

and total-AMPKα (Fig 4B). With TAX pretreatment, AMPK phosphorylation was

266

restored in ethanol-treated HepG2 cells. In addition, TAX suppressed the protein

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levels of ACC evoked by ethanol, and concomitantly activated ACC phosphorylation.

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Our in vitro experiments results were consistent with results of in vivo experiments,

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confirmed that TAX regulates lipid metabolism in ethanol-induced hepatocytes via

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AMPK, and its AMPK-stimulating capability was superior to metformin to a certain

271

extent.

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AMPK activation is linked with the inhibition of P2x7R in ethanol-treated steatotic

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hepatocytes. We observed that ethanol treatment on HepG2 cells induce a

274

significant rise of mature IL-1β expression, which was abolished by TAX pretreatment

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(Fig 4B). Taking into account the downregulation of IL-1β and P2x7R by TAX in

276

steatotic mice livers and hepatocytes, we were intrigued whether P2x7R activation is

277

involved in AMPK-mediated lipid accumulation in hepatocytes. HepG2 cells were

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transfected with siRNA specific P2x7R or scramble siRNA and confirmed by western

279

blot (Fig 5A). Depletion of P2x7R results in the recovery of AMPK phosphorylation

280

despite ethanol exposure (Fig 5B). Application of P2x7R siRNA significantly reduced

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protein expressions of SREBP1, which was increased in ethanol-treated HepG2 cells

282

(Fig 5D). Interestingly, with P2x7R deficiency, TAX pretreatment further enhanced

283

AMPK stimulation and suppressed SREBP1 expression. It indicated that

284

transcriptionally and pharmacologically inhibition of P2x7R will lead to alleviation of 15

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lipid accumulation in hepatocytes.

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IL-1β cleavage initiated by LPS plus ATP is prevented by TAX in hepatocytes. Since

287

ATP is a second signal of P2x7R-dependent LPS-driven NLRP3 inflammasome

288

activation, we next investigated whether TAX will interfere IL-1β production

289

stimulated by LPS plus ATP. LPS provides the first signal for induction of pro-IL-1β,

290

and ATP present a second signal in inflammasome activation to mimic LPS-driven

291

inflammatory response in ALD 11. P2x7R expression was low in normal HepG2 cells,

292

but dramatically increased with stimulation of LPS plus ATP (Fig 6A). Concomitantly

293

pro-IL-1β production and cleavage was also induced by LPS plus ATP stimulation (Fig

294

6A). Pretreatment of TAX prior to LPS/ATP stimulation successfully inhibited P2x7R

295

expression, as well as pro-IL-1β production. P2x7R inhibitor (A438079), caspase-1

296

inhibitor IV and TLR4 inhibitor (CLI-095) also significantly suppressed the protein

297

level of P2x7R. Moreover, caspase-1 inhibitor IV and A438079 partially decreased

298

pro-IL-1β production, while CLI-095 completely suppressed pro-IL-1β production.

299

These results suggested that inhibition effects of TAX on IL-1β production works

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through P2x7R-NLRP3 inflammasome.

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DISCUSSION

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Alcoholic liver disease (ALD) presents a broad spectrum of disorders, ranging

303

from steatosis, alcoholic hepatitis and fibrosis, even to hepatocellular caner.

304

Managing ALD is currently in a limited pharmacotherapy stage 35. The current Food

305

and Drug administration (FDA)-approved medication for ALD is naltrexone, disulfiram,

306

prednisolone and pentoxifylline

307

modest survival gains or only reserved for severe ALD, and abstinence and nutritional

308

support still remain the first line of therapeutic intervention 38.

36, 37

. However, these treatments only enhanced

309

Flavonoids are presented in common food plant-based functional compounds 39.

310

There is experimental evidence that the natural flavonoids show therapeutic

311

potential in the treatment of alcoholic liver steatosis through inhibition of lipid

312

accumulation and inflammation in liver

313

demonstrated that TAX protected alcoholic liver steatosis both in vitro and in vivo.

314

We provided preliminary evidence that TAX administration prevented the

315

imbalanced lipid metabolism induced by ethanol intake. TAX supplementation

316

significantly inhibited AMPK-mediated lipid metabolism in hepatocytes by inhibiting

317

P2x7R-dependent inflammatory response. With dose of TAX (25 mg/kg) we didn’t

318

observe adverse effect on hepatic lipid accumulation and inflammation. According to

319

Guidance for Industry Estimating the Maximum Safe Starting Dose in Initial Clinical

320

Trials for Therapeutics in Adult Healthy Volunteers (issued by U.S. Department of

321

Health and Human Services, Food and Drug Administration), a human equivalent

40-42

. The data from our research

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dose of TAX for starting Phase I trials converted from 25 mg/kg in mice would be

323

approximately 121.8 mg daily for a 60 kg man, which are feasible daily doses for

324

humans through dietary sources.

325

AMPK regulates the balance of lipid metabolism and activated by its upstream 43, 44

326

kinase, LKB1

. AMPK activation raises the lipid β-oxidation and conversely,

327

downregulates lipid synthesis. Currently, we investigated the effects of TAX on the

328

phosphorylation of AMPK and LKB1. Our data demonstrated that TAX remarkably

329

increased the activity of LKB1 and AMPK, indicating that its inhibition of lipid

330

accumulation probably linked to liver-specific activation of LKB1-AMPK. AMPK

331

phosphorylates and inhibits ACC, which is involved in lipid metabolism, while AMPK

332

also regulates SREBP1 activity, which controls lipid synthesis

333

SREBP1 expression and stimulated phosphorylated ACC in alcohol-induced mice

334

steatosis liver, suggesting that TAX modulated lipid metabolism by inhibiting lipid

335

biosynethesis and promoting lipid β-oxidation.

45

. TAX suppressed

336

Ethanol and its metabolites in liver can induce inflammatory responses. Also

337

chronic binge alcohol intake sensitizes hepatocytes to inflammatory signals and

338

impairs the biological function of hepatocytes 9. As shown in Fig 3A and 4B, IL-1β

339

secretion and IL-1β production was abolished by TAX application in alcohol-induced

340

steatotic liver and steatotic hepatocytes, suggesting ethanol sensitizes hepatocytes

341

to IL-1 signaling in response to stimuli. IL-1β maturation and secretion in alcoholic

342

liver steatosis was caspase-1-dependently processed

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. In addition, NLRP3

Journal of Agricultural and Food Chemistry

343

inflammasome activation leads to severe liver inflammation and hepatocytes

344

pyroptosis, characterize by caspase-1 activation

345

NLRP3 inflammasome activation in livers of alcohol-treated mice supported by

346

increased levels of the cleaved caspase-1 and NLRP3 expression, while TAX

347

suppressed those to normal level, indicating that TAX inhibited inflammasome

348

activation in alcoholic liver steatosis, consequently suppressed IL-1β secretion to

349

avoid accelerating the inflammation.

46

. Ethanol consumption increased

350

IL-1β release via NLRP3 activation needs two-step signals, including the

351

synthesis of pro-IL-1β via TLRs and the cleavage of pro-IL-1β to biologically active,

352

mature IL-1β then release to extracellular, induced by PAMP or DAMP 47. Among the

353

DAMP, high levels of ATP acts as a second danger signal and mediated by P2x7R in

354

inflammasome activation 48. Currently several groups reported P2x7R promotes IL-1β

355

release NLRP3 inflammasome signaling-dependently in macrophages and neutrophils

356

50, 51

357

might be a potential target for liver fibrosis. Although P2x7R also is known as a key

358

modulator in nonalcoholic steatohepatitis

359

will regulate alcoholic steatohepatitis 12. Therefore, we are intrigued in whether TAX

360

regulates alcoholic liver steatosis via P2x7R suppression, especially in hepatocytes. As

361

expected ethanol increased P2x7R protein expression, which was suppressed by TAX

362

administration accompanied by decreased IL-1β secretion and caspase-1 activity (Fig

363

3), suggesting that TAX might be involved in the inhibition of NLRP3 inflammasome

364

activation through regulating P2X7R signaling.

. We also reported the inhibition of P2x7R-NLRP3 inflammasome activation

52, 53

, we reported that blockade of P2x7R

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knockdown in HepG2 cells could restore the activity of AMPK, and decreased SREBP1

366

expression (Fig 5). It confirmed P2x7R activation is involved in the regulation of lipid

367

metabolism in ethanol-induced steatotic hepatocyte. With TAX supplementation,

368

AMPK activity further recovered in P2x7R deficient cells, indicating the inhibition of

369

lipid accumulation effect by TAX is partially dependent P2x7R signaling.

370

Hepatocytes present in a microenvironment with high level of bacterial LPS and

371

ATP in the development of alcoholic liver disease. The increase of serum ATP was

372

observed in alcohol-fed mice (Fig 1F) and ALD patients

373

hepatocytes release ATP, and these sterile danger signal promotes inflammasome in

374

LPS-primed immune cells. And increased gut permeability resulted in the increased

375

translocation of LPS from gut to the liver through the portal circulation

376

successfully inhibited the increasing serum ATP and LBP level in alcohol-induced

377

steatotic mice, suggesting that TAX might regulate TLR4 and P2X7R signaling. To

378

evaluate how hepatocytes will response to two-step signals stimulus with TAX

379

interference, we applied LPS for the ligand of TLR4 as a first signal and ATP for ligand

380

of P2x7R as a second signal to stimulate heaptocytes. Our data demonstrated that

381

two-step signal significantly activated P2x7R and induced IL-1β cleavages. All above

382

increasing evoked by two-step signal was abolished by pretreatment of TAX, A438079

383

(P2x7R inhibitor), caspase-1 inhibitor or CLI-095 (TLR4 antagonist). These results

384

hinted us TAX might be a pharmacological inhibitor of P2x7R and could target P2x7R

385

activation in hepatocytes.

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. Alcohol-damaged

49

. TAX

Journal of Agricultural and Food Chemistry

386

In conclusion, our research demonstrated that TAX affects lipid synthesis and

387

lipid oxidation through the activity of AMPK, thereby inhibiting alcohol-induced lipid

388

accumulation in mice liver. And TAX has certain inhibitory effect on the activation of

389

P2x7R-caspase-1-NLRP3 inflammasome induced by alcohol, indicating that TAX might

390

be a potential candidate to treat alcoholic liver steatosis.

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AUTHOR INFORMATION

392

Author Contribution

393

Ms. Yu Zhang and Dr. Quan Jin are the primary investigators in this study. Ms. Xia

394

Li and Ms. Min Jiang participated in part of in vivo experiments. Mrs. Ben-Wen Cui

395

and Ms. Kai-Li Xia participated in part of in vitro experiments. Dr. Yan-Ling Wu

396

participated in part of statistical analysis. Dr. Li-Hua Lian and Prof. Ji-Xing Nan

397

designed the whole study and wrote the manuscript.

398

Funding

399

This study was supported by a grant from the National Natural Science

400

Foundation of China (81560597, 81660689and 81460564), and partially by Science

401

and Technology Planning Projects from the Science and Technology Department of

402

Jilin

403

20180519010JH).

404

Conflict of Interest Statement

Province

(20160101205JC,

20180414048GH,

20180201065YY

and

405

The authors declare that the research was conducted in the absence of any

406

commercial or financial relationships that could be construed as a potential conflict

407

of interest.

408

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REFERENCES

410

(1) Warner, D. R.; Liu, H.; Miller, M. E.; Ramsden, C. E.; Gao, B.; Feldstein, A. E.;

411

Schuster, S.; McClain, C. J.; Kirpich, I. A., Dietary Linoleic Acid and Its Oxidized

412

Metabolites Exacerbate Liver Injury Caused by Ethanol via Induction of Hepatic

413

Proinflammatory Response in Mice. The American journal of pathology 2017, 187,

414

2232-2245.

415

(2) Orman, E. S.; Odena, G.; Bataller, R., Alcoholic liver disease: pathogenesis,

416

management, and novel targets for therapy. Journal of gastroenterology and

417

hepatology 2013, 28 Suppl 1, 77-84.

418

(3) Yin, H.; Hu, M.; Zhang, R.; Shen, Z.; Flatow, L.; You, M., MicroRNA-217 promotes

419

ethanol-induced fat accumulation in hepatocytes by down-regulating SIRT1. J Biol

420

Chem 2012, 287, 9817-26.

421

(4) Mandal, S.; Mukhopadhyay, S.; Bandhopadhyay, S.; Sen, G.; Biswas, T.,

422

14-Deoxyandrographolide alleviates ethanol-induced hepatosteatosis through

423

stimulation of AMP-activated protein kinase activity in rats. Alcohol 2014, 48, 123-32.

424

(5) Shearn, C. T.; Smathers, R. L.; Jiang, H.; Orlicky, D. J.; Maclean, K. N.; Petersen, D.

425

R., Increased dietary fat contributes to dysregulation of the LKB1/AMPK pathway and

426

increased damage in a mouse model of early-stage ethanol-mediated steatosis. The

427

Journal of nutritional biochemistry 2013, 24, 1436-45.

428

(6) Commerford, S. R.; Peng, L.; Dube, J. J.; O'Doherty, R. M., In vivo regulation of

429

SREBP-1c in skeletal muscle: effects of nutritional status, glucose, insulin, and leptin.

430

American journal of physiology. Regulatory, integrative and comparative physiology 23

ACS Paragon Plus Environment

Page 24 of 41

Page 25 of 41

Journal of Agricultural and Food Chemistry

431

2004, 287, R218-27.

432

(7) Everitt, H.; Hu, M.; Ajmo, J. M.; Rogers, C. Q.; Liang, X.; Zhang, R.; Yin, H.; Choi, A.;

433

Bennett, E. S.; You, M., Ethanol administration exacerbates the abnormalities in

434

hepatic lipid oxidation in genetically obese mice. Am J Physiol Gastrointest Liver

435

Physiol 2013, 304, G38-47.

436

(8) Yin, H.; Hu, M.; Liang, X.; Ajmo, J. M.; Li, X.; Bataller, R.; Odena, G.; Stevens, S. M.,

437

Jr.; You, M., Deletion of SIRT1 from hepatocytes in mice disrupts lipin-1 signaling and

438

aggravates alcoholic fatty liver. Gastroenterology 2014, 146, 801-11.

439

(9) Wang, H. J.; Gao, B.; Zakhari, S.; Nagy, L. E., Inflammation in alcoholic liver

440

disease. Annu Rev Nutr 2012, 32, 343-68.

441

(10) Kesar, V.; Odin, J. A., Toll-like receptors and liver disease. Liver international :

442

official journal of the International Association for the Study of the Liver 2014, 34,

443

184-96.

444

(11) Iracheta-Vellve, A.; Petrasek, J.; Satishchandran, A.; Gyongyosi, B.; Saha, B.;

445

Kodys, K.; Fitzgerald, K. A.; Kurt-Jones, E. A.; Szabo, G., Inhibition of sterile danger

446

signals, uric acid and ATP, prevents inflammasome activation and protects from

447

alcoholic steatohepatitis in mice. Journal of hepatology 2015, 63, 1147-55.

448

(12)Li, X.; Zhang, Y.; Jin, Q.; Xia, K. L.; Jiang, M.; Cui, B. W.; Wu, Y. L.; Song, S. Z.; Lian, L.

449

H.; Nan, J. X., LKB1/AMPK-Mediated Regulation by Gentiopicroside Ameliorates

450

P2x7R-Dependent Alcoholic Hepatosteatosis. Br J Pharmacol 2018.

451

(13) Slimestad, R.; Fossen, T.; Vagen, I. M., Onions: a source of unique dietary

452

flavonoids. Journal of agricultural and food chemistry 2007, 55, 10067-80.

24

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

453

(14) Wallace, S. N.; Carrier, D. J.; Clausen, E. C., Batch solvent extraction of

454

flavanolignans from milk thistle (Silybum marianum L. Gaertner). Phytochemical

455

analysis : PCA 2005, 16, 7-16.

456

(15) Weidmann, A. E., Dihydroquercetin: More than just an impurity? European

457

journal of pharmacology 2012, 684, 19-26.

458

(16) Polyak, S. J.; Morishima, C.; Lohmann, V.; Pal, S.; Lee, D. Y.; Liu, Y.; Graf, T. N.;

459

Oberlies, N. H., Identification of hepatoprotective flavonolignans from silymarin.

460

Proceedings of the National Academy of Sciences of the United States of America

461

2010, 107, 5995-9.

462

(17) Kim, Y. J.; Choi, S. E.; Lee, M. W.; Lee, C. S., Taxifolin glycoside inhibits dendritic

463

cell responses stimulated by lipopolysaccharide and lipoteichoic acid. The Journal of

464

pharmacy and pharmacology 2008, 60, 1465-72.

465

(18) Sun, X.; Chen, R. C.; Yang, Z. H.; Sun, G. B.; Wang, M.; Ma, X. J.; Yang, L. J.; Sun, X.

466

B., Taxifolin prevents diabetic cardiomyopathy in vivo and in vitro by inhibition of

467

oxidative stress and cell apoptosis. Food and chemical toxicology : an international

468

journal published for the British Industrial Biological Research Association 2014, 63,

469

221-32.

470

(19) Liang, L.; Gao, C.; Luo, M.; Wang, W.; Zhao, C.; Zu, Y.; Efferth, T.; Fu, Y.,

471

Dihydroquercetin (DHQ) induced HO-1 and NQO1 expression against oxidative stress

472

through the Nrf2-dependent antioxidant pathway. Journal of agricultural and food

473

chemistry 2013, 61, 2755-61.

474

(20) Guo, H.; Zhang, X.; Cui, Y.; Zhou, H.; Xu, D.; Shan, T.; Zhang, F.; Guo, Y.; Chen, Y.;

25

ACS Paragon Plus Environment

Page 26 of 41

Page 27 of 41

Journal of Agricultural and Food Chemistry

475

Wu, D., Taxifolin protects against cardiac hypertrophy and fibrosis during

476

biomechanical stress of pressure overload. Toxicology and applied pharmacology

477

2015, 287, 168-77.

478

(21) Brusselmans, K.; Vrolix, R.; Verhoeven, G.; Swinnen, J. V., Induction of cancer cell

479

apoptosis by flavonoids is associated with their ability to inhibit fatty acid synthase

480

activity. J Biol Chem 2005, 280, 5636-45.

481

(22) Kourelis, T. V.; Siegel, R. D., Metformin and cancer: new applications for an old

482

drug. Med Oncol 2012, 29, 1314-27.

483

(23) Ouyang, J.; Parakhia, R. A.; Ochs, R. S., Metformin activates AMP kinase through

484

inhibition of AMP deaminase. J Biol Chem 2011, 286, 1-11.

485

(24) Lian, L. H.; Wu, Y. L.; Song, S. Z.; Wan, Y.; Xie, W. X.; Li, X.; Bai, T.; Ouyang, B. Q.;

486

Nan, J. X., Gentiana manshurica Kitagawa reverses acute alcohol-induced liver

487

steatosis through blocking sterol regulatory element-binding protein-1 maturation.

488

Journal of agricultural and food chemistry 2010, 58, 13013-9.

489

(25)Li, X.; Zhang, Y.; Jin, Q.; Xia, K. L.; Jiang, M.; Cui, B. W.; Wu, Y. L.; Song, S. Z.; Lian, L.

490

H.; Nan, J. X., Liver kinase B1/AMP-activated protein kinase-mediated regulation by

491

gentiopicroside ameliorates P2X7 receptor-dependent alcoholic hepatosteatosis. Br J

492

Pharmacol 2018, 175, 1451-1470.

493

(26) Jiang, M.; Wu, Y. L.; Li, X.; Zhang, Y.; Xia, K. L.; Cui, B. W.; Lian, L. H.; Nan, J. X.,

494

Oligomeric proanthocyanidin derived from grape seeds inhibited NF-kappaB signaling

495

in activated HSC: Involvement of JNK/ERK MAPK and PI3K/Akt pathways. Biomed

496

Pharmacother 2017, 93, 674-680.

26

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

Page 28 of 41

497

(27)Petrasek, J.; Bala, S.; Csak, T.; Lippai, D.; Kodys, K.; Menashy, V.; Barrieau, M.; Min,

498

S. Y.; Kurt-Jones, E. A.; Szabo, G., IL-1 receptor antagonist ameliorates

499

inflammasome-dependent alcoholic steatohepatitis in mice. J Clin Invest 2012, 122,

500

3476-89.

501

(28) Triantafilou, M.; Triantafilou, K., Lipopolysaccharide recognition: CD14, TLRs and

502

the LPS-activation cluster. Trends Immunol 2002, 23, 301-4.

503

(29) Sakura, T.; Morioka, T.; Shioi, A.; Kakutani, Y.; Miki, Y.; Yamazaki, Y.; Motoyama, K.;

504

Mori, K.; Fukumoto, S.; Shoji, T.; Emoto, M.; Inaba, M., Lipopolysaccharide-binding

505

protein is associated with arterial stiffness in patients with type 2 diabetes: a

506

cross-sectional study. Cardiovasc Diabetol 2017, 16, 62.

507

(30) Nagy, L. E., Molecular aspects of alcohol metabolism: transcription factors

508

involved in early ethanol-induced liver injury. Annu Rev Nutr 2004, 24, 55-78.

509

(31) Viollet, B.; Guigas, B.; Leclerc, J.; Hebrard, S.; Lantier, L.; Mounier, R.; Andreelli, F.;

510

Foretz, M., AMP-activated protein kinase in the regulation of hepatic energy

511

metabolism: from physiology to therapeutic perspectives. Acta Physiol (Oxf) 2009,

512

196, 81-98.

513

(32) Hou, X.; Xu, S.; Maitland-Toolan, K. A.; Sato, K.; Jiang, B.; Ido, Y.; Lan, F.; Walsh, K.;

514

Wierzbicki, M.; Verbeuren, T. J.; Cohen, R. A.; Zang, M., SIRT1 regulates hepatocyte

515

lipid metabolism through activating AMP-activated protein kinase. J Biol Chem 2008,

516

283, 20015-26.

517

(33) Tilg, H.; Moschen, A. R.; Szabo, G., Interleukin-1 and inflammasomes in alcoholic

518

liver

disease/acute

alcoholic

hepatitis

and

nonalcoholic

27

ACS Paragon Plus Environment

fatty

liver

Page 29 of 41

Journal of Agricultural and Food Chemistry

519

disease/nonalcoholic steatohepatitis. Hepatology 2016, 64, 955-65.

520

(34) Pochareddy, S.; Edenberg, H. J., Chronic alcohol exposure alters gene expression

521

in HepG2 cells. Alcohol Clin Exp Res 2012, 36, 1021-33.

522

(35) Addolorato, G.; Russell, M.; Albano, E.; Haber, P. S.; Wands, J. R.; Leggio, L.,

523

Understanding and treating patients with alcoholic cirrhosis: an update. Alcohol Clin

524

Exp Res 2009, 33, 1136-44.

525

(36) Edwards, S.; Kenna, G. A.; Swift, R. M.; Leggio, L., Current and promising

526

pharmacotherapies, and novel research target areas in the treatment of alcohol

527

dependence: a review. Curr Pharm Des 2011, 17, 1323-32.

528

(37) Vuittonet, C. L.; Halse, M.; Leggio, L.; Fricchione, S. B.; Brickley, M.; Haass-Koffler,

529

C. L.; Tavares, T.; Swift, R. M.; Kenna, G. A., Pharmacotherapy for alcoholic patients

530

with alcoholic liver disease. Am J Health Syst Pharm 2014, 71, 1265-76.

531

(38) Frazier, T. H.; Stocker, A. M.; Kershner, N. A.; Marsano, L. S.; McClain, C. J.,

532

Treatment of alcoholic liver disease. Therap Adv Gastroenterol 2011, 4, 63-81.

533

(39) Qiu, P.; Dong, Y.; Li, B.; Kang, X. J.; Gu, C.; Zhu, T.; Luo, Y. Y.; Pang, M. X.; Du, W. F.;

534

Ge, W. H., Dihydromyricetin modulates p62 and autophagy crosstalk with the

535

Keap-1/Nrf2 pathway to alleviate ethanol-induced hepatic injury. Toxicol Lett 2017,

536

274, 31-41.

537

(40) Luo, G.; Huang, B.; Qiu, X.; Xiao, L.; Wang, N.; Gao, Q.; Yang, W.; Hao, L.,

538

Resveratrol attenuates excessive ethanol exposure induced insulin resistance in rats

539

via improving NAD+ /NADH ratio. Mol Nutr Food Res 2017, 61.

540

(41) Wang, F.; Liu, J. C.; Zhou, R. J.; Zhao, X.; Liu, M.; Ye, H.; Xie, M. L., Apigenin

28

ACS Paragon Plus Environment

Journal of Agricultural and Food Chemistry

541

protects against alcohol-induced liver injury in mice by regulating hepatic

542

CYP2E1-mediated oxidative stress and PPARalpha-mediated lipogenic gene

543

expression. Chem Biol Interact 2017, 275, 171-177.

544

(42) Rafacho, B. P.; Stice, C. P.; Liu, C.; Greenberg, A. S.; Ausman, L. M.; Wang, X. D.,

545

Inhibition of diethylnitrosamine-initiated alcohol-promoted hepatic inflammation

546

and precancerous lesions by flavonoid luteolin is associated with increased sirtuin 1

547

activity in mice. Hepatobiliary Surg Nutr 2015, 4, 124-34.

548

(43)Woods, A.; Williams, J. R.; Muckett, P. J.; Mayer, F. V.; Liljevald, M.; Bohlooly, Y. M.;

549

Carling, D., Liver-Specific Activation of AMPK Prevents Steatosis on a High-Fructose

550

Diet. Cell Rep 2017, 18, 3043-3051.

551

(44) Jiang, Z.; Zhou, J.; Zhou, D.; Zhu, Z.; Sun, L.; Nanji, A. A., The

552

adiponectin-SIRT1-AMPK pathway in alcoholic fatty liver disease in the rat. Alcohol

553

Clin Exp Res 2015, 39, 424-33.

554

(45) Rasineni, K.; Casey, C. A., Molecular mechanism of alcoholic fatty liver. Indian J

555

Pharmacol 2012, 44, 299-303.

556

(46) Wree, A.; Eguchi, A.; McGeough, M. D.; Pena, C. A.; Johnson, C. D.; Canbay, A.;

557

Hoffman, H. M.; Feldstein, A. E., NLRP3 inflammasome activation results in

558

hepatocyte pyroptosis, liver inflammation, and fibrosis in mice. Hepatology 2014, 59,

559

898-910.

560

(47) Gombault, A.; Baron, L.; Couillin, I., ATP release and purinergic signaling in NLRP3

561

inflammasome activation. Front Immunol 2012, 3, 414.

562

(48) Burnstock, G., The therapeutic potential of purinergic signalling. Biochem

29

ACS Paragon Plus Environment

Page 30 of 41

Page 31 of 41

Journal of Agricultural and Food Chemistry

563

Pharmacol 2017.

564

(49) Szabo, G., Gut-liver axis in alcoholic liver disease. Gastroenterology 2015, 148,

565

30-6.

566

(50) Karmakar, M.; Katsnelson, M. A.; Dubyak, G. R.; Pearlman, E., Neutrophil P2X7

567

receptors mediate NLRP3 inflammasome-dependent IL-1beta secretion in response

568

to ATP. Nat Commun 2016, 7, 10555.

569

(51) Englezou, P. C.; Rothwell, S. W.; Ainscough, J. S.; Brough, D.; Landsiedel, R.;

570

Verkhratsky, A.; Kimber, I.; Dearman, R. J., P2X7R activation drives distinct IL-1

571

responses in dendritic cells compared to macrophages. Cytokine 2015, 74, 293-304.

572

(52) Chatterjee, S.; Das, S., P2X7 receptor as a key player in oxidative stress-driven

573

cell fate in nonalcoholic steatohepatitis. Oxid Med Cell Longev 2015, 2015, 172493.

574

(53) Das, S.; Seth, R. K.; Kumar, A.; Kadiiska, M. B.; Michelotti, G.; Diehl, A. M.;

575

Chatterjee, S., Purinergic receptor X7 is a key modulator of metabolic oxidative

576

stress-mediated autophagy and inflammation in experimental nonalcoholic

577

steatohepatitis. Am J Physiol Gastrointest Liver Physiol 2013, 305, G950-63.

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579

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Figure captions

581

Figure 1. TAX attenuates ethanol-induced lipid accumulation in mice liver. Mice

582

were gavaged with ethanol (5 g/kg) every 12 h for three times. TAX (1, 5 and

583

25mg/kg) was gavaged simultaneously with ethanol intake. (A) Chemical structure of

584

TAX. (B) Serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST).

585

(C) Serum and hepatic TG contents. Each value is expressed as the mean ± SD (n = 6).

586

HE (D, 200 × original magnification) and Oil red O staining (E, 400 × original

587

magnification) were performed with samples obtained at 4 h after the last ethanol

588

administration. (F) ATP level in mice serum. (G) Lipopolysaccharide (LPS)-Binding

589

Protein (LBP) protein levels in mice serum. ## p < 0.01, ### p < 0.001significantly

590

different when compared with normal group; * p