Metabolic diseases characterized by an imbalance in energy homeostasis represent a significant global health challenge. Individuals with metabolic diseases often suffer from complications related to disorders in lipid metabolism, such as obesity and non-alcoholic fatty liver disease (NAFLD). Understanding core genes involved in lipid metabolism can advance strategies for the prevention and treatment of these conditions. Stearoyl-CoA desaturase 1 (SCD1) is a key enzyme in lipid metabolism that converts saturated fatty acids into monounsaturated fatty acids. SCD1 plays a crucial regulatory role in numerous physiological and pathological processes, including energy homeostasis, glycolipid metabolism, autophagy, and inflammation. Abnormal transcription and epigenetic activation of Scd1 contribute to abnormal lipid accumulation by regulating multiple signaling axes, thereby promoting the development of obesity, NAFLD, diabetes, and cancer. This review comprehensively summarizes the key role of SCD1 as a metabolic hub gene in various (patho)physiological contexts. Further it explores potential translational avenues, focusing on the development of novel SCD1 inhibitors across interdisciplinary fields, aiming to provide new insights and approaches for targeting SCD1 in the prevention and treatment of metabolic diseases.
Stearoyl-CoA Desaturase/metabolism* ; Humans ; Metabolic Diseases/physiopathology* ; Lipid Metabolism/physiology* ; Animals ; Obesity/enzymology* ; Non-alcoholic Fatty Liver Disease

Obesity and metabolic dysfunction-associated steatotic liver disease (MASLD) are linked to numerous chronic conditions, including cardiovascular disease, atherosclerosis, chronic kidney disease, and type II diabetes. Previous research identified the natural flavonoid diosmin, derived from Chrysanthemum morifolium, as a regulator of glucose metabolism. However, its effects on lipid metabolism and underlying mechanisms remained unexplored. The AMP-activated protein kinase (AMPK) pathway serves a critical function in glucose and lipid metabolism. The relationship between diosmin and the AMPK pathway has not been previously documented. This investigation examined diosmin's capacity to reduce lipid content through AMPK pathway activation in hepatoblastoma cell line G2 (HepG2) and 3T3-L1 cells. The study revealed that diosmin inhibits lipogenesis, indicating its potential as an anti-obesity agent in obese mice. Moreover, diosmin demonstrated effective MASLD alleviation in vivo. These findings suggest that diosmin may represent a promising therapeutic candidate for treating obesity and MASLD.
Diosmin/administration & dosage* ; Animals ; AMP-Activated Protein Kinases/genetics* ; Humans ; Non-alcoholic Fatty Liver Disease/enzymology* ; Mice ; Obesity/enzymology* ; Hep G2 Cells ; Male ; 3T3-L1 Cells ; Mice, Inbred C57BL ; Signal Transduction/drug effects* ; Lipid Metabolism/drug effects* ; Chrysanthemum/chemistry* ; Lipogenesis/drug effects*

OBJECTIVETo investigate the effect of apigenin on the protein expression levels of peroxisome proliferator-activated receptors (PPARs) in liver tissues of rats with nonalcoholic steatohepatitis (NASH).

METHODSThe NASH rat model was established by feeding of a high-fat diet. Unmodeled rats served as the normal controls. The modeled rats were divided into a model control group, Essentiale treatment grouP(300 mg/kg/day),and three apigenin treatment groups for low-dose (15 mg/kg/day), moderate-dose (30 mg/kg/day) and high-dose (60 mg/kg/day). After 13 weeks of treatment,changes in insulin sensitivity from pre-treatment baseline were assessed by measuring the alanine aminotransferase (ALT), aspartate aminotransferase (AST),total cholesterol (TC),triglycerides (TG),low-density and high-density lipoprotein cholesterol (LDL-C and HDL-C),fasting blood glucose (FBG) and fasting insulin (FINS).The liver index and HOMA-IR were also calculated.Protein and gene expression of PPARα and PPARgamma in liver tissue were assessed by immunohistochemistry and RT-PCR.Statistical analysis was performed by the LSD test and Games-Howell test.

RESULTSThe apigenin-treated groups showed a significantly greater change in insulin sensitivity than the untreated model group,with the most significant change occurring in the high-dose grouP(P less than 0.05).Compared with the untreated model group,the apigenin-treated groups showed lower levels of ALT (95.4+/-7.3),AST (183.7+/-14.3),TC (1.61+/-0.25),TG (1.23+/-0.21),LDL-C (1.86+/-0.14),FBG (5.29+/-1.45) and FINS (0.76+/-0.86),but a higher level of HDL-C (1.04+/-0.17); again,the high-dose group showed the greatest change (all P less than 0.05).Compared to the untreated model group,the apigenin-treated groups showed significantly lower liver index (3.75+/-0.25 vs.2.90+/-0.17) and HOMA-IR (1.34+/-0.06 vs.0.18+/-0.04),with the high-dose group showing the greatest change (both P less than 0.05). Compared to the untreated model group,the apigenin-treated groups showed higher levels of protein and mRNA of PPARα (18.27+/-4.05 and 0.63+/-0.02,respectively) and PPARgamma(8.48+/-5.05 and 0.39+/-0.02),with the high-dose group showing the greatest change (all P < 0.05).

CONCLUSIONApigenin can improve glucose tolerance,lipid metabolism and insulin resistance while decreasing blood levels of TC,TG,LDL-C,FBG,FINS and HOMA-IR,and increasing HDL-C in NASH,as shown in a high-fat diet induced rat model, and may have therapeutic potential.

Alanine Transaminase ; metabolism ; Animals ; Apigenin ; pharmacology ; Aspartate Aminotransferases ; metabolism ; Blood Glucose ; metabolism ; Cholesterol ; metabolism ; Disease Models, Animal ; Insulin ; metabolism ; Insulin Resistance ; Lipid Metabolism ; Liver ; enzymology ; Non-alcoholic Fatty Liver Disease ; metabolism ; PPAR alpha ; metabolism ; PPAR gamma ; metabolism ; Peroxisome Proliferator-Activated Receptors ; metabolism ; Rats ; Rats, Sprague-Dawley ; Triglycerides ; metabolism

OBJECTIVETo investigate the potential preventive effects of metformin on non-alcoholic fatty liver disease (NAFLD) and roles of phospholipase A2/lysophosphatidylcholine pathway in hepatocyte lipoapoptosis in a rat NAFLD model induced by high-fat diet.

METHODMale SD rats (n = 36) were randomly divided into three groups with 12 rats in each and treated with different diet and drugs: group I: ordinary diet, group II: high-fat diet, group III: high-fat diet and metformin. Ten weeks later, the rats were sacrificed and their body weight and liver weight were obtained, serum lipid metabolic indexes, insulin resistance indexes and secretory phospholipase A2 (sPLA2), lysophosphatidylcholine (LPC) levels and other parameters were measured. Phospholipase A2 mRNA expression levels were measured by quantitative reverse transcription-polymerase chain reaction (RT-PCR). In addition, the histological changes of liver tissue were analyzed.

RESULTCompared to ordinary diet group, the rat's liver weight (g) (16.92 ± 2.49 vs. 12.16 ± 0.82), hepatic exponent (0.034 ± 0.004 vs. 0.026 ± 0.002), serum alanine aminotransferase (U/L) (45.43 ± 9.73 vs. 29.42 ± 6.73), triglyceride (mmol/L) (1.22 ± 0.24 vs. 0.85 ± 0.19), cholesterol (mmol/L) (2.00 ± 0.37 vs. 1.49 ± 0.33), lipoprotein(a) (mmol/L) (743.86 ± 32.19 vs. 648.42 ± 78.87), low-density lipoprotein (mmol/L) (1.31 ± 0.35 vs. 0.65 ± 0.22), insulin (mmol/L) (22.16 ± 5.16 vs. 16.86 ± 5.35), insulin resistance index(5.10 ± 1.45 vs. 3.59 ± 0.99), free fatty acid (mEq/L) (0.57 ± 0.10 vs. 0.35 ± 0.07), sPLA2 [µmol/(min·ml)] (0.130 ± 0.016 vs. 0.098 ± 0.024), lysophosphatidylcholine (µmol/L) (707.26 ± 92.48 vs. 508.87 ± 96.50), leptin (pg/ml (80.08 ± 17.73 vs. 65.11 ± 14.09), liver triglyceride (mg/g) (13.57 ± 0.65 vs. 12.03 ± 1.14), cholesterol (mg/g) (2.19 ± 0.15 vs. 1.94 ± 0.12) (P < 0.05) were significantly increased in high-fat diet group. Moreover, degree of hepatic steatosis was significantly higher and sPLA2 mRNA expression was also significantly increased. Secondly, in comparison with high-fat diet group, early metformin treatment significantly reduced the rat's body weight (g) (394.40 ± 33.10 vs. 491.86 ± 26.45), liver weight (g) (13.24 ± 1.16 vs. 16.92 ± 2.49), serum alanine aminotransferase (U/L) (30.40 ± 4.50 vs. 45.43 ± 9.73), triglyceride (mmol/L) (0.75 ± 0.19 vs. 1.22 ± 0.24), cholesterol (mmol/L) (1.61 ± 0.38 vs. 2.00 ± 0.37), insulin (mmol/L) (16.96 ± 5.60 vs. 22.16 ± 5.16), insulin resistance index (3.75 ± 1.41 vs. 5.10 ± 1.45), sPLA2 [µmol/(min·ml)] (0.101 ± 0.009 vs. 0.130 ± 0.016), lysophosphatidylcholine (µmol/L) (549.92 ± 90.78 vs. 707.26 ± 92.48), liver triglyceride (mg/g) (11.23 ± 1.70 vs. 13.57 ± 0.65), cholesterol (mg/g) (1.97 ± 0.20 vs. 2.19 ± 0.15) (P < 0.05). Moreover, degree of hepatic steatosis was significantly lower and sPLA2 mRNA expression was also significantly decreased by metformin. Thirdly, when compared to ordinary diet group, metformin could also significantly increase hepatic exponent (0.034 ± 0.004 vs. 0.026 ± 0.002) and low-density lipoprotein level (mmol/L) (0.96 ± 0.34 vs. 0.65 ± 0.22) (P < 0.05). However, it had no impact on hepatic steatosis and sPLA2 expression (P > 0.05).

CONCLUSIONIt was indicated that metformin has potent effects on improving lipid metabolism and insulin resistance in high-fat diet induced non-alcoholic fatty liver disease rat model. The liver protective mechanisms of metformin in non-alcoholic fatty liver disease may be contributed to down-regulation of secretory phospholipase A2 mRNA expression, decrease in serum secretory phospholipase A2, lysophosphatidylcholine, lower inflammatory response and protect mitochondrial function.

Animals ; Apoptosis ; Disease Models, Animal ; Down-Regulation ; Fatty Liver ; drug therapy ; enzymology ; pathology ; Insulin Resistance ; Lipid Metabolism ; Lysophosphatidylcholines ; metabolism ; Male ; Metformin ; pharmacology ; Non-alcoholic Fatty Liver Disease ; Phospholipases A2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; Signal Transduction