• Biomolecules & Therapeutics
• /
• v.30 no.3
• /
• pp.246-256
• /
• 2022

The present study focused on the potential mechanism of betulin (BT), a pentacyclic triterpenoid isolated from the bark of white birch (Betula pubescens), against chronic alcohol-induced lipid accumulation and metaflammation. AML-12 and RAW 264.7 cells were administered ethanol (EtOH), lipopolysaccharide (LPS) or BT. Male C57BL/6 mice were fed Lieber-DeCarli liquid diets containing 5% EtOH for 4 weeks, followed by single EtOH gavage on the last day and simultaneous treatment with BT (20 or 50 mg/kg) by oral gavage once per day. In vitro, MTT showed that 0-25 mM EtOH and 0-25 µM BT had no toxic effect on AML-12 cells. BT could regulate sterolregulatory-element-binding protein 1 (SREBP1), lipin1/2, P2X7 receptor (P2X7r) and NOD-like receptor family, pyrin domains-containing protein 3 (NLRP3) expressions again EtOH-stimulation. Oil Red O staining also indicated that BT significantly reduced lipid accumulation in EtOH-stimulated AML-12 cells. Lipin1/2 deficiency indicated that BT might mediate lipin1/2 to regulate SREBP1 and P2X7r expression and further alleviate lipid accumulation and inflammation. In vivo, BT significantly alleviated histopathological changes, reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) and triglyceride (TG) levels, and regulated lipin1/2, SREBP1, peroxisome proliferator activated receptor α/γ (PPARα/γ) and PGC-1α expression compared with the EtOH group. BT reduced the secretion of inflammatory factors and blocked the P2X7r-NLRP3 signaling pathway. Collectively, BT attenuated lipid accumulation and metaflammation by regulating the lipin1/2-mediated P2X7r signaling pathway.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.42 no.10
• /
• pp.1576-1584
• /
• 2013

This study is carried out to assess the relative effects of different doses of dietary glucose or fructose on non-alcoholic fatty liver disease (NAFLD) and hepatic metaflammation in a rodent model of type 2 diabetes. KK/HlJ male mice were fed experimental diets as follows: 1) control (CON), 2) moderate glucose (MG, 30% of total calories as glucose), 3) high glucose (HG, 60% of total calories as glucose), 4) moderate fructose (MF, 30% of total calories as fructose), and 5) high fructose (HF, 60% of total calories as fructose) for three weeks. Food intake was not affected by treatments. Compared with HF, HG not only increased serum fasting glucose and area under the curve during oral glucose tolerance test, but also decreased the levels of serum insulin and adiponectin. It indicated that glucose control was complicated via high glucose intake. High fructose treatment led to increased triglyceride in the serum and liver. In comparison to HG, high fructose diet activated NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome consisting of apoptosis-associated speck-like protein containing a CARD (ASC), NLRP3 and caspase 1, which increases interleukin (IL)-$1{\beta}$ maturation and secretion. The activation of NLRP3 inflammasome was accompanied by increased levels of tumor necrosis factor alpha (TNF-${\alpha}$) and IL-6. However, the expression of NLRP3 inflammasome components and pro-inflammatory cytokines did not differ between CON and HG. These data suggested that dietary fructose triggers hepatic metaflammation accompanied by NLRP3 inflammasome activation and has deleterious effects on NAFLD.

• Biomolecules & Therapeutics
• /
• v.29 no.1
• /
• pp.22-30
• /
• 2021

Till the 21st century, fatty acids were considered as merely building blocks for triglycerides, phospholipids, or cholesteryl esters. However, the discovery of G protein-coupled receptors (GPCRs) for free fatty acids at the beginning of the 21st century challenged that idea and paved way for a new field of research, merged into the field of receptor pharmacology for intercellular lipid mediators. Among the GPCRs for free fatty acids, free fatty acid receptor 4 (FFA4, also known as GPR120) recognizes long-chain polyunsaturated fatty acids such as DHA and EPA. It is significant in drug discovery because it regulates obesity-induced metaflammation and GLP-1 secretion. Our study reviews information on newly developed FFA4 agonists and their application in pathophysiologic studies and drug discovery. It also offers a potency comparison of the FFA4 agonists in an AP-TGF-α shedding assay.

• Journal of Nutrition and Health
• /
• v.46 no.4
• /
• pp.307-314
• /
• 2013

Resveratrol (RSV) exerts several beneficial effects on metabolism and metaflammation-related diseases, including diabetes and non-alcoholic fatty liver disease (NAFLD). The purpose of this study is to investigate whether RSV affects pathophysiology of diabetes and NAFLD as well as hepatic autophagy in a rodent model of diet induced obesity (DIO). DIO was induced in a subset of C57BL/6J mice fed a high fat (HF, 45% kcal fat) diet. After six weeks of HF diet treatment, RSV (8 mg/kg/day) was administered via an osmotic pump for a period of four weeks. Therefore, the experimental groups were as follows: 1) lean control (CON), 2) HF diet-induced obese control (HF), and 3) HF_RSV. Body weight and food intake were monitored daily. Fasting glucose, insulin, and adiponectin in serum and lipid profiles in serum and liver were analyzed. In addition, the autophagic process was investigated using transmission electron microscopy (TEM). Body weight and food intake were not affected by RSV treatment. Impaired glucose control accompanied by DIO was recovered with RSV as shown by lower levels of fasting serum glucose and insulin when compared with HF obese controls. In addition, RSV treatment resulted in increased levels of serum adiponectin, however, indices of lipid profile in serum and livers were reduced. Results of TEM analysis showed that a HF diet induced excessive autophagy with the presence of double-membrane autophagosomes, which was ameliorated by RSV. The regulatory effect of RSV on autophagy was confirmed by the altered LC3-II formation, which increased with a HF diet and was decreased by RSV treatment. These results suggest that RSV treatment improves glucose control and lipid profile and these beneficial effects may be mediated by an altered autophagic process.