Adult ; Case-Control Studies ; Fatty Liver ; genetics ; Female ; Humans ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; Sterol Regulatory Element Binding Protein 1 ; genetics

OBJECTIVES: Insulin signaling pathway plays an important role in metabolic associated fatty liver disease (MAFLD), however, the association between polymorphisms of genes related to insulin signaling pathway and MAFLD remains unclear. This study aims to investigate the association between insulin signaling pathway-related gene polymorphisms and gene-gene interactions with MAFLD susceptibility in obese children so as to provide scientific basis for further study of genetic mechanism. METHODS: A total of 502 obese children with MAFLD who admitted to Hunan Provincial Children's Hospital from September 2019 to October 2021, were recruited as a case group, and 421 obese children with non-MAFLD admitted during the same period were recruited as a control group. Socio-demographic information, preterm birth history, eating habits, and exercise status of the subjects were collected by inquiry survey, and anthropometric information was collected by physical measurement. At the same time, 2 mL of venous blood was collected to extract DNA, and the polymorphism of insulin signaling pathway-related genes (5 representative candidate genes, 12 variants) was detected. Multivariate Logistic regression analysis was used to investigate the association between insulin signaling pathway-related gene polymorphisms and MAFLD in obese children. RESULTS: After adjusting for confounder factors, INS rs3842748 was significantly associated with the risk of MAFLD in obese children in allele, heterozygous, and dominant models [OR and 95% CI 1.749 (1.053 to 2.905), 1.909 (1.115 to 3.267), 1.862 (1.098 to 3.157), all P<0.05]; INS rs3842752 was significantly associated with the risk of MAFLD in obese children in heterozygous and dominant models [OR and 95% CI 1.736 (1.028 to 2.932), 1.700 (1.015 to 2.846), all P<0.05]. NR1H3 rs3758674 was significantly correlated with the risk of MAFLD in obese children in allele model [OR and 95% CI 0.716 (0.514 to 0.997), P<0.05]. SREBP-1c rs2297508 was significantly associated with the risk of MAFLD in obese children in allele and dominant models [OR and 95% CI 0.772 (0.602 to 0.991) and 0.743 (0.557 to 0.991), all P<0.05]. SREBP-1c rs8066560 was significantly associated with the risk of MAFLD in obese children in allele, heterozygous, and dominant models [OR and 95% CI 0.759 (0.589 to 0.980), 0.733 (0.541 to 0.992), 0.727 (0.543 to 0.974), all P<0.05]. NR1H3 rs3758674 mutant C and SREBP-1c rs2297508 mutant G had interaction in the development of MAFLD in obese children [OR and 95% CI 0.407 (0.173 to 0.954), P<0.05]. CONCLUSIONS The INS, NR1H3, and SREBP-1c gene polymorphisms in the insulin signaling pathway are associated with the susceptibility of MAFLD in obese children, but the functions and mechanisms of these genes need to be further studied.
Child ; Infant, Newborn ; Humans ; Female ; Pediatric Obesity/genetics* ; Sterol Regulatory Element Binding Protein 1 ; Premature Birth ; Non-alcoholic Fatty Liver Disease ; Signal Transduction/genetics* ; Insulins

OBJECTIVE: To investigate effects of berberine (BBR) on cholesterol synthesis in HepG2 cells with free fatty acid (FFA)-induced steatosis and to explore the underlying mechanisms. METHODS: A steatosis cell model was induced in HepG2 cell line fed with FFA (0.5 mmol/L, oleic acid:palmitic acid = 2:1), and then treated with three concentrations of BBR; cell viability was assessed with cell counting kit-8 assays. Lipid accumulation in cells was observed through oil red O staining and total cholesterol (TC) content was detected by TC assay. The effects of BBR on cholesterol synthesis mediators were assessed by Western blotting and quantitative polymerase chain reaction. In addition, both silent information regulator 1 (SIRT1) and forkhead box transcription factor O1 (FoxO1) inhibitors were employed for validation. RESULTS: FFA-induced steatosis was successfully established in HepG2 cells. Lipid accumulation and TC content in BBR groups were significantly lower (P < 0.05, P < 0.01), associated with significantly higher mRNA and protein levels of SIRT1(P < 0.05, P < 0.01), significantly lower sterol regulatory element-binding protein 2 (SREBP2) and 3-hydroxy 3-methylglutaryl-CoA reductase levels (P < 0.05, P < 0.01), as well as higher Acetyl-FoxO1 protein level (P < 0.05, P < 0.01) compared to the FFA only group. Both SIRT1 inhibitor SIRT1-IN-1 and FoxO1 inhibitor AS1842856 blocked the BBR-mediated therapeutic effects. Immunofluorescence showed that the increased SIRT1 expression increased FoxO1 deacetylation, and promoted its nuclear translocation. CONCLUSION BBR can mitigate FFA-induced steatosis in HepG2 cells by activating SIRT1-FoxO1-SREBP2 signal pathway. BBR may emerge as a potential drug candidate for treating nonalcoholic hepatic steatosis.
Berberine/pharmacology* ; Cholesterol ; Forkhead Box Protein O1/genetics* ; Humans ; Non-alcoholic Fatty Liver Disease/drug therapy* ; Sirtuin 1/genetics* ; Sterol Regulatory Element Binding Proteins

As a culinary and medicinal herb, rosemary is widely used. The present work aimed to investigate the effects of rosemary extracts on metabolic diseases and the underlying mechanisms of action. Liver cells stably expressing SREBP reporter were used to evaluate the inhibitory effects of different fractions of rosemary extracts on SREBP activity. The obese mice induced by Western-type diet were orally administered with rosemary extracts or vehicle for 7 weeks, the plasma and tissue lipids were analyzed. SREBPs and their target genes were measured by quantitative RT-PCR. We demonstrated that the petroleum ether sub-fraction of rosemary extracts (PER) exhibited the best activity in regulating lipid metabolism by inhibiting SREBPs, while water and n-BuOH sub-fraction showed the SREBPs agonist-effect. After PER treatment, there was a significant reduction of total SREBPs in liver cells. PER not only decreased SREBPs nuclear abundance, but also inhibited their activity, resulting in decreased expression of SREBP-1c and SREBP-2 target genes in vitro and in vivo. Inhibiting SREBPs by PER decreased the total triglycerides and cholesterol contents of the liver cells. In the mice fed with Western-type diet, PER treatment decreased TG, TC, ALT, glucose, and insulin in blood, and improved glucose tolerance and insulin sensitivity. Furthermore, PER treatment also decreased lipid contents in liver, brown adipose tissue, and white adipose tissue. Our results from the present study suggested that petroleum ether fraction of rosemary extracts exhibited the best potential of improving lipid metabolism by inhibiting SREBPs activity.
Alkanes ; chemistry ; Animals ; Cholesterol ; metabolism ; Hepatocytes ; drug effects ; metabolism ; Humans ; Hyperlipidemias ; drug therapy ; genetics ; metabolism ; Insulin ; metabolism ; Insulin Resistance ; Liver ; drug effects ; metabolism ; Male ; Mice ; Mice, Inbred C57BL ; Petroleum ; analysis ; Plant Extracts ; administration & dosage ; chemistry ; isolation & purification ; Rosmarinus ; chemistry ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Sterol Regulatory Element Binding Protein 2 ; genetics ; metabolism

The aim of the study was to construct a recombinant adenovirus overexpression vector for Sterol Regulatory Element Binding Protein-1 (SREBP-1) of Xinong Saanen dairy goat, and to detect its effect on genes related to fatty acid metabolism in goat mammary epithelial cells, to establish foundation for further study of its roles in metabolism of fatty acid synthesis and lactation. First, we designed primers based on the SREBP-1 gene sequence in GenBank for PCR amplification and inserted the sequence into shuttle vector pAdTrack-CMV. The recombinant plasmid pAdTrack-CMV-SREBP-1 linearized by Pme I was transformed into E. coli BJ5183 competence cell containing the backbone vector pAdEasy-1 to obtain recombinant vector pAd-SREBP-1 by homologous recombination. pAd-SREBP-1 was linearized by Pac I and transfected into HEK 293 cell. Then we infected goat mammary epithelial cells with recombinant adenovirus which was packaged in HEK 293 cell line. The results showed that the recombinant adenovirus vector containing SREBP-1 was successfully constructed, and the titer of virus was 10(9) U/mL. Compared with the control group, mRNA level of SREBP-1 increased by about 15 times after infected for 48 h and 30 times after infected for 72 h. Fatty acid synthase (FASN) and Acetyl-CoA carboxylase (ACC) was upregulated by almost 2 times. The expression level of Peroxisome proliferator activated receptorgamma (PPARgamma) increased by 1.5 times. Liver X receptoralpha (LXRalpha) and Adipose triglyceride lipase (ATGL) upregulated by 1.2 times compared with that of control. But Stearoyl-coenzyme A desaturase (SCD) had no obvious change. In conclusion, SREBP-1 can activate the expression of genes related to fatty acid synthesis in mammary epithelial cells of Xinong Saanen dairy goat, demonstrated a regulatory function on the fatty acid metabolism in goat mammary gland.
Adenoviridae ; genetics ; metabolism ; Animals ; Epithelial Cells ; cytology ; metabolism ; Fatty Acids ; metabolism ; Female ; Gene Expression Regulation ; Goats ; genetics ; HEK293 Cells ; Humans ; Lipid Metabolism ; genetics ; Mammary Glands, Animal ; cytology ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism ; Transfection

OBJECTIVEPreparing rat model of non-alcoholic fatty liver disease by fat-rich diet to observe the expression and the role of LXR-alpha in rat nonalcoholic fatty liver disease.

METHODSThirty-six SD rats were randonmized into basic diet-control group and high-fat diet group. Each of the two groups was subdivided into 3 subgroups (4, 8, 12 weeks). Changes in animal weight, liver exponent and the level of TG and TC in serum and liver were observed dynamically. Meanwhile,the expression of hepatocyte LXR-alpha and SREBP-1c were assayed by Reverse transcript-polymerase chain reaction at 4, 8, 12 weeks. The level of steatosis was observed under light microscope after haematoxylon-eosin (HE) staening.

RESULTSCompared with control group, body weight, liver exponent, TG and Tc in serum and liver were increased dynamically in model groups. Compared with control group, the mRNA of LXR-a and SREBP-1c were obviously increased dynamically in model groups (P < 0.05) .

CONCLUSIONThe increase of LXR-alpha and SREBP-1c in liver may be concered with energy disorder and closely associated with the activity of inflammation and the severity of the liver damage in NAFLD rats.

Animals ; Disease Models, Animal ; Fatty Liver ; genetics ; metabolism ; Humans ; Liver X Receptors ; Male ; Orphan Nuclear Receptors ; genetics ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism

OBJECTIVETo investigate the effect of Hepatitis B Virus X Protein (HBx) on the expression of lipid metabolism-related genes and its role in pathogenesis of hepatocyte fatty degeneration.

METHODSHepatitis B Virus X gene eukaryon expression vector pIRES2-eGFP-HBx was transfected into HepG2 cells to establish HepG2/HBx cell model for HBx expression. HepG2 cells transfected with pIRES2-eGFP (HepG2/pIRES2 cell) and non-transfected were used as controls. At 24, 48 and 72 hours after transfection, the expression of green fluorescent protein (GFP) was observed by fluorescence microscope and the triglyceride(TG) content was detected. RT-PCR and Western blot were applied to detect the levels of sterol regulatory element binding protein-1 (SREBP-1), liver x receptor alpha (LXRalpha) mRNA and the levels of HBx, LXRalpha and fatty acid synthase (FAS) protein. At 24, 48 and 72 hours after transfection, the expression of GFP was found in HepG2/HBx and HepG2/pIRES2 cells, and increased gradually. The expression of HBx was detected only in HepG2/HBx cells, and was increased with time after transfection (F = 32.21, P less than 0.01). These suggested successful obtaining of HepG2-HBx cell model for HBx expression.

RESULTSAt 24h, 48h and 72h after transfection, the expression levels of LXRalpha mRNA (0.386+/-0.055, 0.505+/-0.071, 0.649+/-0.058 ) and SREBP-1 mRNA (0.395+/-0.055, 0.548+/-0.047, 0.795+/-0.058), as well as the levels of LXRalpha protein(0.178+/-0.036, 0.263+/-0.047, 0.347+/-0.058) and FAS protein(0.436+/-0.055, 0.608+/-0.053, 0.827+/-0.046) in HepG2-HBx group were dramatically higher than those in the controls at the same time points (all P less than 0.05/0.01), and were gradually increased with time (all P less than 0.05/0.01). A positive correlationship was observed between HBX protein level and the LXRalpha, SREbP-1 mRNA and LXRalpha, FAS protein levels. The difference of TG content between HepG2/HBx group and control groups was not statistically significant (P more than 0.05).

CONCLUSIONSHBx-LXRalpha-SREBP-1/FAS pathway suggested regulating transcription and expression of lipid metabolism-related genes, which might be one of the important molecular mechanism causing hepatocyte fatty degeneration.

Carcinoma, Hepatocellular ; metabolism ; Fatty Acid Synthase, Type I ; metabolism ; Hep G2 Cells ; Humans ; Lipid Metabolism ; genetics ; Liver Neoplasms ; metabolism ; Liver X Receptors ; Orphan Nuclear Receptors ; metabolism ; Sterol Regulatory Element Binding Protein 1 ; metabolism ; Trans-Activators ; genetics ; Transfection

The study aimed to investigate the effect of anemoside B4(B4) on fatty acid metabolism in mice with colitis-associated cancer(CAC). The CAC model was established by azoxymethane(AOM)/dextran sodium sulfate(DSS) in mice. Mice were randomly divided into a normal group, a model group, and low-, medium-, and high-dose anemoside B4 groups. After the experiment, the length of the mouse colon and the size of the tumor were measured, and the pathological alterations in the mouse colon were observed using hematoxylin-eosin(HE) staining. The slices of the colon tumor were obtained for spatial metabolome analysis to analyze the distribution of fatty acid metabolism-related substances in the tumor. The mRNA levels of SREBP-1, FAS, ACCα, SCD-1, PPARα, ACOX, UCP-2, and CPT-1 were determined by real-time quantitative PCR(RT-qPCR). The results revealed that the model group showed decreased body weight(P<0.05) and colon length(P<0.001), increased number of tumors, and increased pathological score(P<0.01). Spatial metabolome analysis revealed that the content of fatty acids and their derivatives, carnitine, and phospholipid in the colon tumor was increased. RT-qPCR results indicated that fatty acid de novo synthesis and β-oxidation-related genes, such as SREBP-1, FASN, ACCα, SCD-1, ACOX, UCP-2, and CPT-1 mRNA expression levels increased considerably(P<0.05, P<0.001). After anemoside B4 administration, the colon length increased(P<0.01), and the number of tumors decreased in the high-dose anemoside B4 group(P<0.05). Additionally, spatial metabolome analysis showed that anemoside B4 could decrease the content of fatty acids and their derivatives, carnitine, and phospholipids in colon tumors. Meanwhile, anemoside B4 could also down-regulate the expression of FASN, ACCα, SCD-1, PPARα, ACOX, UCP-2, and CPT-1 in the colon(P<0.05, P<0.01, P<0.001). The findings of this study show that anemoside B4 may inhibit CAC via regulating fatty acid metabolism reprogramming.
Mice ; Animals ; Sterol Regulatory Element Binding Protein 1 ; Colitis-Associated Neoplasms ; PPAR alpha/genetics* ; Colonic Neoplasms/genetics* ; Colon ; Azoxymethane ; RNA, Messenger ; Dextran Sulfate ; Colitis/drug therapy* ; Mice, Inbred C57BL ; Disease Models, Animal

OBJECTIVETo study the effect of SREBP-1c silencing on lipid metabolism and expression of inflammatory chemokines in a NAFLD model with endoplasmic reticulum stress.

METHODNAFLD model was established in L02 cells treated with oleic acid. SREBP-1c expression was inhibited using RNA interference with a p Silencer-1.0-U6-4476 vector. After transfection with p Silencer-1.0-U6-4476 or control vector for 0 h, 24 h, 48 h and 72 h, the extent of fatty degeneration was shown by Oil Red O staining. The mRNA and protein expression of inflammatory chemokine CCL2 and basic fibroblast growth factor-21 (FGF21) were determined by real time PCR and Western blot respectively.

RESULTSSREBP-1c silenced L02 cells showed fat droplets with smaller diameter and attenuated fatty deposition, as compared with control cells. The relative CCL2 mRNA levels in SREBP-1c silencing vector transfected L02 cells were 1.03+/-0.11 for 0 h, 1.11+/-0.21 for 24 h, 0.88+/-0.16 for 48 h, and 1.05+/-0.15 for 72 h, which showed no significant difference as compared with control cells (P>0.05, respectively). In addition, no difference was found between the different time points within the same group (P>0.05). However, CCL2 protein levels in SREBP-1c silenced cells were 1.19+/-0.15, 1.07+/-0.18, 0.48+/-0.14, and 0.05+/-0.24 after transfection for 0 h, 24 h, 48 h, and 72 h respectively, which were significantly downregulated as compared to the control group (P<0.01). And CCL2 protein levels between different time points in SREBP-1c silenced cells were also distinct (P<0.01). The relative FGF21 mRNA levels in SREBP-1c silenced L-02 cells were 1.01+/-0.08, 0.91+/-0.22, 0.98+/-0.20, and 1.02+/-0.12 for 0 h, 24 h, 48 h, and 72 h respectively, which were not statistically different as compared with the corresponding control cells. Statistic difference of FGF21 mRNA levels in SREBP-1c knockdown cells of different time points was not found (P>0.05). In striking contrast, robust down regulation of FGF21 protein in SREBP-1c silenced cells was observed, with 0.81+/-0.05, 0.66+/-0.12, 0.58+/-0.08 and 0.19+/-0.13 after transfection for 0 h, 24 h, 48 h and 72 h respectively, as compared to control group (P<0.01). And differences in FGF21 protein level between different time points in SREBP-1c silenced cells were also demonstrated (P<0.01).

CONCLUSIONSREBP-1c knockdown attenuated fatty deposition in oleic acid treated L02 cells. In addition, silencing of SREBP-1c expression reduced expressions of CCL2 and FGF21 proteins posttranscriptionally, which may play a role in endoplasmic reticulum stress induced inflammatory response in NAFLD.

Cell Line ; Chemokine CCL2 ; metabolism ; Endoplasmic Reticulum Stress ; Fibroblast Growth Factors ; metabolism ; Gene Knockdown Techniques ; Hepatocytes ; metabolism ; Humans ; Lipid Metabolism ; RNA Interference ; Sterol Regulatory Element Binding Protein 1 ; genetics

OBJECTIVETo investigate the effects of 54G/C polymorphism of sterol regulatory element-binding protein-1c gene (SREBP-1c) on serum lipid ratios and their response to high-carbohydrate/low-fat (HC/LF) diet in healthy youth.

METHODSAfter a regular diet for 7 days of wash-out, 56 healthy youth (22.89 +/- 1.80 yrs) were given HC/LF diet for 6 days. The regular diet contained 54% carbohydrate, 15% protein, and 31% fat of the total energy. The HC/LF diet contained 70% carbohydrate, 15% protein, and 15% fat of the total energy. The serum lipids and glucose were measured on the 1st, 8th and 14th days. The ratios of TG/HDL-C, log (TG/HDL-C), TC/HDL-C, and LDL-C/HDL-C were calculated. The 54G/C polymorphism of SREBP-1c gene was analyzed by PCR-RFLP method.

RESULTSNo significant difference was found in lipid ratios and glucose at baseline and after regular diet in subjects with different genotypes in either the whole studied population or in males or females only. However, after HC/LF diet, LDL-C/HDL-C was significantly lower in females carrying the C allele than those of GG homozygotes (P< 0.05). Compared with those before HC/LF diet, TC/HDL-C and LDL-C/HDL-C were significantly decreased in all the subjects (P< 0.05). When gender was taken into account, significant increase of TG/HDL-C and log(TG/HDL-C) was found only in females with GG genotype (P< 0.05). All the subjects experienced significant decrease of TC/HDL-C and LDL-C/HDL-C regardless of their genders and genotypes (P< 0.05).

CONCLUSIONThe 54G/C polymorphism of SREBP-1c gene can influence the response of TG/HDL-C and log(TG/HDL-C) to HC/LF diet in females. The C allele may be a protective factor to prevent the increase of TG induced by HC/LF diet in females.

Adult ; Dietary Carbohydrates ; pharmacology ; Dietary Fats ; pharmacology ; Female ; Gene Frequency ; Genotype ; Health ; Humans ; Lipids ; blood ; Male ; Polymorphism, Single Nucleotide ; Sex Characteristics ; Sterol Regulatory Element Binding Protein 1 ; genetics ; Young Adult