Research on the mechanism of hypoxia promoting the migration of lung adenocarcinoma A549 cells / 中国应用生理学杂志

Objective: To investigate the mechanism that hypoxia promotes the migration of lung adenocarcinoma A549 cells. Methods: A549 cells were cultured and cells that knockdown of acetyl-CoA carboxylase 1 (ACC1) were obtained by transfection with lentivirus, and cells that knockdown of sterol regulatory element-binding proteins-1 (SREBP-1) were obtained by treated with si-RNA. A549 cells were treated with hypoxia combined with hypoxia inducible factor-1α (HIF-1α) inhibitor PX-478 (25 μmol); Hypoxia combined with linoleic acid (LA) (20 μmol) treated A549 cells with ACC1 knockdown, and A549 cells with SREBP-1 knockdown were treated by hypoxia. Transwell migration assay was used to detect cell migration. Western blot was conducted to detect HIF-1α, ACC1 and epithelial mesenchymal transition (EMT) related proteins, Vimentin, E-Cadherin and SREBP-1; Real-time fluorescent quantitative polymerase chain reaction (RT-qPCR) was performed to detect the changes of ACC1 and SREBP-1 mRNA in A549 cells after hypoxia and HIF-1α inhibitor PX-478 (25 μmol) treatment. Each experiment was repeated three times. Results: Compared with the normoxic control group, hypoxia promoted the migration of A549 cells (P＜0.01), and up-regulated the expressions of ACC1, HIF-1α (all P＜0.01) and SREBP-1 (P＜0.05). PX-478 (25 μmol) inhibited the migration of A549 cells induced by hypoxia and down-regulated the expression of SREBP-1 (all P＜0.05). ACC1 mRNA and SREBP-1 mRNA levels were increased after hypoxia treatment of A549 cells (all P＜0.05). The levels of ACC1 mRNA and SREBP-1 mRNA were decreased after A549 cells treated with hypoxia combined with PX-478 (25 μmol) for 24 h (P＜0.05, P＜0.01). Knockdown of SREBP-1 in A549 cells was obtained by transfection with si-RNA. Transwell migration assay showed the number of cell migration in si-SREBP-1 group was less than that in normoxia control group (P＜0.01). The si-SREBP-1 group and the si-NC group were treated with hypoxia. Compared with the control group, the number of cell migration in the si-SREBP-1 group was decreased (P＜0.01), however, the difference was not statistically significant compared with the normoxia si-SREBP-1 group (P＞0.05). Western blot showed that the expression of ACC1 in the si-SREBP-1 group was lower than that in the control group (P＜0.01). Compared with the control group, the expression of ACC1 was decreased after si-SREBP-1 group treated with hypoxia (P＜0.01). Knockdown of ACC1 inhibited the migration of A549 cells (P＜0.05). After knockdown of ACC1, the migration number of A549 cells under normoxia and 5% O2 conditions had no significant difference (P＞0.05). Application of LA under hypoxia condition rescued ACC1-knockdown induced inhibitory effect on hypoxia-promoted A549 cell migration (P＜0.05). Conclusion: Hypoxia promotes migration of lung adenocarcinoma A549 cells by regulating fatty acid metabolism through HIF-1α/SREBP-1/ACC1 pathway.

Effect of milk on sebaceous gland spots and the IGF-1/SREBP-1/ACC-1 signaling pathway in golden hamsters / 中华皮肤科杂志

Objective:To investigate the effect of milk on sebum secretion in golden hamsters, and to explore its possible mechanism of action.Methods:Eighteen golden hamsters were randomly and equally divided into 3 groups: blank control group receiving no intervention, whole-milk group gavaged with whole milk, and skimmed-milk group gavaged with skimmed milk. The gavage feeding was performed at a dose of 2.5 ml twice a day for 4 consecutive weeks. The maximum transverse diameter and maximum longitudinal diameter of bilateral sebaceous gland spots were measured on days 0, 7, 14, 21 and 28 after the start of intervention, and the area of sebaceous gland spots was calculated; at 24 hours after the last gavage, bilateral sebaceous gland spot tissues were resected, and subjected to immunohistochemical study to determine the expression of insulin-like growth factor-1 (IGF-1) /sterol regulatory element-binding protein-1 (SREBP-1) /acetyl-coenzyme A carboxylase (ACC-1) signaling pathway in sebaceous gland spots. Statistical analysis was carried out by using repeated measures analysis of variance, one-way analysis of variance for independent groups, Kruskal-Wallis H test, and least significant difference- t test for multiple comparisons. Results:Repeated measures analysis of variance showed that there was no significant difference in the area of sebaceous gland spots of golden hamsters among the 3 groups ( F= 0.96, P= 0.417) . The IGF-1 expression was significantly higher in the skimmed-milk group (0.39 ± 0.03) than in the blank control group (0.35 ± 0.03, t= 2.62, P= 0.021) and whole-milk group (0.33 ± 0.02, t= 3.82, P= 0.002) ; compared with the blank control group (0.36 ± 0.02) , the skimmed-milk group showed significantly increased SREBP-1 expression (0.42 ± 0.04, t= 2.64, P= 0.021) ; the ACC-1 expression was significantly higher in the skimmed-milk group (0.40 ± 0.03) and whole-milk group (0.40 ± 0.05) than in the blank control group (0.34 ± 0.03; t= 2.39, 2.47, P= 0.031, 0.026, respectively) . Conclusion:Milk may promote sebum secretion in golden hamsters through the IGF-1/SREBP-1/ACC-1 signaling pathway.

Metformin regulates AMPK/SREBP-1 pathway and its clinical application / 中国临床药理学与治疗学

Metformin is one of the commonly used hypoglycemic drugs in clinical practice. In addition to hypoglycemia, there are a variety of medical biological values that have been constantly discovered and attracted much attention. In recent years, studies have shown that metformin through activation of AMPK inhibition of sterols regulating element binding protein 1 (SREBP-1) reduce lipid synthesis, in the treatment of liver steatosis, improve insulin sensitivity, prevention Metformin is one of the commonly used hypoglycemic drugs in clinical practice. In addition to hypoglycemia, there are a variety of medical biological values that have been constantly discovered and attracted much attention. In recent years, studies have shown that metformin through activation of AMPK inhibition of sterols regulating element binding protein 1 (SREBP-1) reduce lipid synthesis, in the treatment of liver steatosis, improve insulin sensitivity, prevention of atherosclerosis and cardiovascular dysfunction, tumor, polycystic ovary syndrome and adjuvant therapy of COVID-19 aspects play a role. Therefore, this article reviews the possible mechanism and clinical application of metformin in regulating glucose and lipid metabolism by inhibiting SREBP-1 through activating AMPK.

Relationship between serum SREBP-1, SAP and endocrine metabolism in patients with polycystic ovary syndrome / 中华内分泌外科杂志

Objective:To investigate the relationship between serum sterol regulatory element binding protein-1 (SREBP-1) , serum amyloid P (SAP) and endocrine metabolism in patients with polycystic ovary syndrome.Methods:75 patients with polycystic ovary syndrome (study group) and 70 healthy women (control group) admitted to the First People’s Hospital of Yuhang District from Mar. 2018 to Feb. 2020 were enrolled. Various indexes were detected in both groups, including body mass index (BMI) , SREBP-1, SAP, triglyceride (TG) , total cholesterol (TC) , high-density lipoprotein (HDL-C) , and low-density lipoprotein (LDL-C) , fasting blood glucose (FBG) , fasting insulin (FINS) , and insulin resistance index (HOMA-IR) . The study group was further divided into two subgroups according to BMI, overweight group and normal group. SREBP-1 and SAP were compared between the two groups. Pearson correlation analysis was used to analyze the correlation between SREBP-1, SAP, blood lipid index, blood glucose index and BMI in patients with polycystic ovary syndrome.Results:The body weight and BMI index of study group were higher than those of control group [ (72.23±4.84) kg vs (58.23±3.25) kg, (25.02±2.75) kg/m 2 vs (22.11±1.34) kg/m 2, P<0.05]. The levels of serum SREBP-1 and SAP in the study group were significantly higher than those in the control group [ (334.78±32.06) pg/ml vs (206.34±25.71) pg/ml, (206.34±25.71) mg/U vs (39.16 ±0.58) mg/U, P<0.05]. The expression levels of TG, TC, LDL-C, FBG, FINS, and HOMA-IR in the study group were higher than those in the control group [ (2.32±0.71) vs (1.53±0.52) , (4.85±0.54) vs (3.41±0.66) , (3.06±0.75) vs (2.11±0.89) , (6.45±0.62) vs (5.59±0.76) , (16.14±1.03) vs (13.02±1.34) , (1.67±0.38) vs (1.18± 0.26) , P<0.05]; HDL-C expression level in the study group was lower than that in the control group [ (1.43±0.56) vs (1.71±0.42) , P<0.05]. The levels of SREBP-1 and SAP in overweight group were higher than those in normal group [ (339.19±27.63) pg/ml vs (281.67±20.18) pg/ml, (53.26±0.59) mg/U vs (42.48±0.67) mg/U, P<0.05]. Serum SREBP-1 and SAP in the study group were positively correlated with TG, TC, LDL-C, HOMA-IR, and BMI, and were negatively correlated with HDL-C ( P<0.05) . Conclusion:SREBP-1 and SAP levels are elevated in patients with polycystic ovary syndrome, which are significantly correlated with TG, TC, LDL-C, HOMA-IR, BMI, and HDL-C, and can cause endocrine disorder by affecting glucose and lipid metabolism.

Protective effect of Xiaochaihu Decoction on non-alcoholic steatohepatitis model mice / 中草药

Objective: The protective effect of Xiaochaihu Decoction on non-alcoholic steatohepatitis (NASH) model mice was studied by constructing a methionine-choline deficiency (MCD) diet-induced NASH model in mice. Methods: C57BL/6 mice, as the research objects, were randomly divided into normal control group, model group, Xiaochaihu Decoction (high, medium and low doses) group, Yishanfu group and Qianggan Capsule group. The NASH model was established by feeding MCD feeds, and model intervention was carried out at the same time by giving different drugs in groups; Changes in body weight, daily food intake, and daily water volume of the mice were recorded during the experiment. HE staining of liver tissue was performed at the end of the experiment to observe pathological changes. and the levels of biochemical indicator of alanine aminotransferase (ALT), Aspartate aminotransferase (AST), total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), interleukin 6 (IL-6), and tumor necrosis factor-α (TNF-α) in serum, and the changes of TC and TG levels in liver tissue were detected, RT-PCR was used to detect the expression levels of fatty acid synthase (FAS) and sterol regulatory element binding protein 1c (SREBP-1c) in liver tissues. Results: Data such as mouse weight, daily food intake, daily water intake, and organ coefficients indicated that MCD diet-induced model mice showed weight loss, decreased intake, and decreased liver wet weight. The weight, intake and liver coefficient of mice in Xiaochaihu Decoction group were significantly higher than those in the model group; The results of HE staining showed that Xiaochaihu Decoction could significantly reduce the degree of steatosis and inflammation of liver tissue, and improve the morphology and structure of liver cells; The results of serum biochemical indicators showed that Xiaochaihu Decoction significantly reduced the levels of TG, TC, AST, ALT, IL-6, TNF-α and increased the level of HDL-C in NASH model mice; RT-PCR results showed that the gene expression levels of FAS and SREBP-1c in the liver tissue of the model group mice were significantly increased, and the administration of Xiaochaihu Decoction could significantly reduce the gene expression levels of FAS and SREBP-1c. Conclusion: Xiaochaihu Decoction has obvious protective effect on NASH mouse model induced by MCD diet. It may play a lipid-lowering role by regulating the expression of inhibitors of fatty acid synthetase genes (FAS, SREBP-1c), reducing fat accumulation, and inhibiting the expression of inflammatory factors to improve liver tissue damage.

Therapeutic effects of dimethyldiguanide combined with clomifene citrate in the treatment of polycystic ovary syndrome

SUMMARY OBJECTIVE In view of the high incidence of polycystic ovary syndrome (PCOS) and the unsatisfactory therapeutic effects of dimethyldiguanide or clomifene citrate alone, our study aimed to investigate the therapeutic effects of dimethyldiguanide combined with clomifene citrate in the treatment of PCOS. METHODS A total of 79 patients with POCS and 35 healthy females were included, and endometrial biopsies were obtained. The sterol regulatory element-binding protein-1 (SREBP1) expression in endometrial tissues was detected by qRT-PCR. POC patients were randomly divided into group A (n=40) and group B (n=39). Patients in group A were treated with dimethyldiguanide combined with clomifene citrate, while patients in group B were treated with clomifene citrate alone. The number of mature follicles and cervical mucus score, follicular development rate and single follicle ovulation rate, cycle pregnancy rate, early miscarriage rate, ovulation rate, endometrial thickness, positive rate of three lines sign, follicle stimulating hormone level and luteinizing hormone level were compared between the two groups. RESULTS The expression level of SREBP1 was higher in PCOS patients than that in the healthy control. SREBP1 expression was inhibited after treatment, while the inhibitory effects of combined treatment were stronger than those of clomifene citrate alone. Compared with clomifene citrate alone, the combined treatment improved cervical mucus score, follicle development rate, single follicle ovulation rate, endometrial thickness, positive rate of three lines sign, and follicle-stimulating hormone level. CONCLUSION The therapeutic effect of combined treatment is better than clomifene citrate alone in the treatment of PCOS.

RESUMO OBJETIVO Tendo em vista a alta incidência de síndrome dos ovários policísticos (SOP) e os efeitos terapêuticos insatisfatórios da dimetildiguanida ou do citrato de clomifeno isoladamente, nosso estudo teve como objetivo investigar os efeitos terapêuticos da dimetildiguanida associada ao citrato de clomifeno no tratamento da SOP. MÉTODOS Um total de 79 pacientes com POCS e 35 mulheres saudáveis foram incluídos, e biópsias endometriais foram obtidas. A expressão da proteína de ligação do elemento regulador de esterol-1 (SREBP1) nos tecidos endometriais foi detectada por qRT-PCR. Pacientes POC foram divididos aleatoriamente em grupo A (n=40) e grupo B (n=39). Os pacientes do grupo A foram tratados com dimetildiguanida combinada com citrato de clomifeno, enquanto os pacientes do grupo B foram tratados apenas com citrato de clomifeno. O número de folículos maduros e muco cervical, taxa de desenvolvimento folicular e taxa de ovulação, taxa de gravidez, abortamento precoce, taxa de ovulação, espessura endometrial, taxa positiva de três linhas, nível de hormônio folículo estimulante e nível de hormônio luteinizante foram comparados entre os dois grupos. RESULTADOS O nível de expressão do SREBP1 foi maior nos pacientes com SOP do que no controle normal. A expressão de SREBP1 foi inibida após o tratamento, enquanto os efeitos inibidores do tratamento combinado foram mais fortes do que os do citrato de clomifeno isoladamente. Comparado com o citrato de clomifeno sozinho, o tratamento combinado melhorou significativamente a pontuação do muco cervical, a taxa de desenvolvimento folicular, a taxa de ovulação do folículo único, a espessura endometrial, a taxa positiva de três linhas de sinal e o nível de hormônio folículo estimulante. CONCLUSÃO O efeito terapêutico do tratamento combinado é melhor do que o citrato de clomifeno isolado no tratamento da SOP.

Relationship Between Sterol Regulatory Element Binding Protein-1 and Nucleotide-binding Oligomerization Domain-like Receptor Protein-1 Inflammasome in Patients With Coronary Artery Disease / 中国循环杂志

Objective: To study the relationship between sterol regulatory element binding protein-1 (SREBP-1) and nucleotide-binding oligomerization domain-like receptor protein-1 (NLRP-1) inflammasome in patients with coronary artery disease (CAD). Methods: Our research included in 3 groups: Control group, n=20 normal subjects, SAP (stable angina pectoris) group, n=49 and ACS (acute coronary syndrome) group, n=55. Plasma levels of IL-1β, IL-18 and hs-CRP were examined by ELISA, mRNA and protein expressions of SREBP-1, NLRP-1 and Caspase-1 in peripheral blood mononuclear cells (PBMC) were detected by RT-PCR and Western blot analysis. Relationships between SREBP-1 and NLRP1, Caspase-1, IL-1β, IL-18 were studied. Results: Compared with Control group, ACS group and SAP group had increased plasma levels of IL-1β, IL-18 and hs-CRP, all P<0.05; elevated mRNA and protein expressions of SREBP-1, NLRP-1 and Caspase-1 in PBMC, in addition, those expressions in ACS group was even higher than SAP group, all P<0.05. SREBP-1 level was positively related to NLRP1, Caspase-1, IL-1β and IL-18, all P<0.05. Conclusion: The expressions of SREBP-1 and NLRP1 inflammasome were increased in CAD patients; SREBP-1 and NLRP1 had positive correlation.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism / 中国天然药物

Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.

Quercetin induces cell death in cervical cancer by reducing O-GlcNAcylation of adenosine monophosphate-activated protein kinase / 대한해부학회지

Hyper-O-GlcNAcylation is a general feature of cancer which contributes to various cancer phenotypes, including cell proliferation and cell growth. Quercetin, a naturally occurring dietary flavonoid, has been reported to reduce the proliferation and growth of cancer. Several reports of the anticancer effect of quercetin have been published, but there is no study regarding its effect on O-GlcNAcylation. The aim of this study was to investigate the anticancer effect of quercetin on HeLa cells and compare this with its effect on HaCaT cells. Cell viability and cell death were determined by MTT and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labelling assays. O-GlcNAcylation of AMP-activated protein kinase (AMPK) was examined by succinylated wheat germ agglutinin pulldown and immunoprecipitation. Immunofluorescence staining was used to detect the immunoreactivitiy of O-linked N-acetylglucosamine transferase (OGT) and sterol regulatory element binding protein 1 (SREBP-1). Quercetin decreased cell proliferation and induced cell death, but its effect on HaCaT cells was lower than that on HeLa cells. O-GlcNAcylation level was higher in HeLa cells than in HaCaT cells. Quercetin decreased the expression of global O-GlcNAcylation and increased AMPK activation by reducing the O-GlcNAcylation of AMPK. AMPK activation due to reduced O-GlcNAcylation of AMPK was confirmed by treatment with 6-diazo-5-oxo-L-norleucine. Our results also demonstrated that quercetin regulated SREBP-1 and its transcriptional targets. Furthermore, immunofluorescence staining showed that quercetin treatment decreased the immunoreactivities of OGT and SREBP-1 in HeLa cells. Our findings demonstrate that quercetin exhibited its anticancer effect by decreasing the O-GlcNAcylation of AMPK. Further studies are needed to explore how quercetin regulates O-GlcNAcylation in cancer.

Hypolipidemic effect of SIPI-7623, a derivative of an extract from oriental wormwood, through farnesoid X receptor antagonism / 中国天然药物

Farnesoid X receptor (FXR) is a member of the nuclear receptor superfamily of ligand-activated transcription factors. As a metabolic regulator, FXR plays key roles in bile acid and cholesterol metabolism and lipid and glucose homeostasis. Therefore, FXR is a potential drug target for several metabolic syndromes, especially those related to lipidemia disorders. In the present study, we identified small molecule SIPI-7623, a derivative of an extract from Oriental wormwood (Artemisia capillaris), and found that it specifically upregulated the expression of cholesterol-7-alpha-hydroxylase (CYP7A1), downregulated the expression of sterol-regulatory element-binding protein 1c (SREBP-1c) in the liver, and inhibited the expression of ileal bile acid binding-protein (IBABP) in the ileum of rats. We found that inhibition of FXR by SIPI-7623 decreased the level of cholesterol and triglyceride. SIPI-7623 reduced the levels of cholesterol and triglyceride in in vitro HepG2 cell models, ameliorated diet-induced atherosclerosis, and decreased the serum lipid content on rats and rabbits model of atherosclerosis in vivo. Furthermore, SIPI-7623 decreased the extent of atherosclerotic lesions. Our resutls demonstrated that antagonism of the FXR pathway can be employed as a therapeutic strategy to treat metabolic diseases such as hyperlipidemia and atherosclerosis. In conclusion, SIPI-7623 could be a promising lead compound for development of drugs to treat hyperlipidemia and atherosclerosis.

Emodin reduces FFAs-induced fatty degeneration in HepG2 cells via the AMPK/SREBP-1 pathway / 中国医师杂志

Objective To investigate the effects of emodin on the triglyceride metabolism and oxidative stress in steatosis in HepG2 cells and possible underlying mechanisms.Methods The appropriate concentration of emodin on HepG2 cells were detected by methyl thiazolyl tetrazolium (MTT) assay.HepG2 cells were induced to fat overaccumulation by 1 mmol/L free fatty acids (FFA) (oleate∶ palmitate =2∶1).The model group exposed to 10 μmol/L,20 μmol/L,40 μmol/L emodin.The intracellular lipid accumulation was documented by Oil Red O staining and the content of triglyceride and total cholesterol was observed.Reactive oxygen species (ROS) was determined by flow cytometry.Western blotting was performed to analyze the protein levels of adenosine monophosphate-activated protein kinase (AMPK),phosphorylated AMPK,and sterol regulatory element-binding protein 1 (SREBP-1).Results Emodin reduced lipid accumulation and triglycerides (TG) content (P ＜ 0.05).At the same time,it significantly reduced ROS production (P ＜ 0.05).Moreover,the levels of AMPK and p-AMPK protein were significantly upregulated,and SREBP-1 protein was significantly downregulated with the treatment of emodin (P ＜ 0.01).Conclusions This study has demonstrated that emodin can reduce fatty degeneration induced by FFAs in hepatocytes,and this effect may be partially mediated by the AMPK/SREBP-1 pathway.

Effect of hepatitis C virus nonstructural protein 5A and its domains II on hepatocyte gluconeogenesis in mice / 中华肝脏病杂志

Objective@#To investigate the role of hepatitis C virus nonstructural protein 5A (NS5A) and its domains I, II, and III in regulating gluconeogenesis in mice and the underlying mechanism.@*Methods@#A total of 60 male C57BL/6J mice were randomly divided into six groups. Recombinant lentiviral particles with specific expression of full-length NS5A, NS5A domain I, NS5A domain II, or NS5A domain III were injected via the caudal vein to establish a mouse model, and the group without injection and the group with the injection of the lentiviral particles containing enhanced green fluorescent protein (EGFP) were established as negative control. The effect of full-length NS5A protein and its domains on fasting blood glucose (FBG) and fasting serum insulin (FINS) were measured. Liver tissue was collected to prepare a paraffin section. Immunohistochemistry was used to measure the expression of phosphoenolpyruvate carboxykinase (PEPCK) in hepatocytes, quantitative real-time PCR and/or Western blot were used to measure the expression of NS5A, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), sterol regulatory element-binding protein-1 (SREBP-1), and PEPCK.@*Results@#Compared with the group without injection and the group with the injection of the lentiviral particles containing EGFP, the groups with the injection of the lentiviral particles containing full-length NS5A and NS5A domain II had significant increases in FBG and homeostasis model assessment of insulin resistance index (P < 0.01). Immunohistochemistry and quantitative real-time PCR showed a significant increase in the expression of PEPCK, a key enzyme involved in gluconeogenesis. Western blot showed that full-length NS5A protein and NS5A domain II inhibited the level of p-AMPK and increased the levels of SREBP-1 and PEPCK.@*Conclusion@#NS5A protein and NS5A domain II may affect glucose metabolism in hepatocytes in mice by regulating AMPK/SREBP-1/PEPCK, and NS5A domain II may play an important role in insulin resistance in hepatocytes caused by HCV infection.

Activation of liver X receptor upregulates fatty acid synthase expression in diabetic kidney / 中华内分泌代谢杂志

Objective To investigate the effect and mechanism of liver X receptor ( LXR ) agonist on expression of fatty acid synthase( FAS) in diabetic kidney. Methods In the part of in vivo study, immunostaining was used to detect the FAS protein expression in kidney. 16-week-old male db/db mice on C57BL/6 background were administered via gavage a LXR synthetic agonist, TO901317, at a dose of 3 mg · kg-1 · d-1 or vehicle ( 0. 5%Carboxymethyl Cellulose Sodium, CMC-Na) alone for 7 d;Quantitative RT-PCR and Western blot were used to detect mRNA and protein levels of FAS and SREBP-1. In the part of in vitro study, MCT cell(a mouse murine proximal tubule cell line)was treated with 10μmol/L TO901317 for 24 h or transfected with active SREBP-1c expression vector (SREBP-1cN). HEK293 cells(a human renal tubule cell line)were transfected with mFAS-(1. 7 kb)-luc, LXR expression vector or SREBP-1cN for 12 h. Quantitative RT-PCR and luciferase reproter assay were utilized to examine FAS mRNA level and FAS promoter activity. Results FAS was abundantly expressed in renal cortex, with low expresson in renal glomeruli. The mRNA and protein expressious of FAS in kidney of db/db mice were lowered compared with db/m mice. TO90137 treatment increased FAS mRNA expression by 1. 3-fold. TO901317 increased expression of SREBP-1 in kidneys of db/m and db/db mice by 5. 1-fold and 17-fold, respectively. TO901317 and overexpression of SREBP-1c increased expression of FAS in MCT cells by 1. 5-fold and 1. 8-fold. Transcription activity of FAS were induced by TO901317, LXR, and SREBP-1cN overexpressions in HEK293 cells. Conclusions Both direct(LXRE)and indirect(SREBP-1c)mechanisms may contribute to the up-regulation of FAS expression by LXR in renal proximal tubule cells.

Protective effect of emilia sonchifolia on rats with experimental hepatic steatosis and its molecular mechanism / 中国中西医结合急救杂志

Objective To investigate the preventive effects of emilia sonchifolia on experimental hepatic steatosis in rats and its molecular mechanism.Methods Seventy Sprague-Dawley (SD) rats were randomly divided into five groups: normal control, model, high dose emilia sonchifolia, low dose emilia sonchifolia groups and high dose emilia sonchifolia + phosphorylated extracellular signal regulated protein kinase 1/2 (pERK1/2) inhibitor (PD98059) group (PD group). In normal control group, the rats were fed with normal diet, and in the other four groups, the rats were fed with high fat and low protein diet combined with 30% carbon tetrachloride (CCl4) peanut oil 2 mL/kg subcutaneous injection, once every 3 days for consecutive 3 weeks to establish animal models with hepatic steatosis. In emilia sonchifolia high and low dose groups, 5.0 g/kg and 2.5 g/kg doses of emilia sonchifolia were given respectively by gavage, once a day. In PD group, after administration of emilia sonchifolia high dose by gavage once a day, additionally PD98059 0.3 mg/kg was injected through a tail vein, once a week. After 3 weeks, all rats were switched to normal diet and treatment continued as before. At the end of the 5th week, liver tissues were taken for pathological analyses. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), total cholesterol (TC), and triglyceride (TG) were determinated by automatic biochenical analyzer. The positive cell count and protein expressions of sterol-regulatory element binding protein 1 (SREBP-1), pERK1/2, toll like receptor 4 (TLR4) and high mobility group box-1 protein (HMGB1) were tested by immunohistochemistry, Western Blot and flow cytometry. The levels of superoxide dismutase (SOD) and malonaldehyde (MDA) in liver cell homogenate were detected by hydroxylamine and TBA method.Results Compared with the model group, the lobular inflammation in high and low dose emilia sonchifolia groups and PD group was attenuated (1.50±0.53, 1.80±0.43, 1.20±0.42 vs. 2.30±0.48), and ALT, AST, TC, TG, SREBP-1, and MDA were significantly decreased, the decrease in high dose emilia sonchifolia group being the most significant [ALT (U/L): 51.91±6.95 vs. 66.50±12.15, AST (U/L): 125.70±5.62 vs. 147.10±10.52, TC (mmol/L): 1.79±1.04 vs. 2.81±1.08, TG (mmol/L): 0.87±0.55 vs. 1.17±0.67, SREBP-1: (30.60±5.56)% vs. (53.10±5.02)%, MDA (nmol/mg): 5.20±0.87 vs. 10.61±5.45,P 0.05]. While the above index values in PD group were close to those in high dose emilia sonchifolia group, showing that PD98059 had no impact on emilia sonchifolia's action.Conclusions Emilia sonchifolia can alleviate hepatic injury and attenuate lobular inflammation in rat experimental hepatic steatosis. Its mechanism is possibly related to the reduction of oxidative stress reaction, and SREBP-1 may be as a mediator involved in the action.

Effect of increased serum TNF-αon lipid accumulation in kidney of diabetes / 中国药理学通报

Aim Todeterminetherelationshipbe-tween serum TNF-α and renal abnormal lipid metabo-lismindiabeticmice.Methods CD1micewerein-jected intraperitoneally with STZ (150 mg·kg-1 ) and the type 1 diabetic mice were determined with high fasting blood glucose ( >16. 7 mmol · L-1 ) 72 hours after injection. After fed for one month, normal control mice and diabetic mice were sacrificed. The serum TNF-α level was detected by the method of ELISA. Immunohistochemistry and Western blot were used to explore the expression of SREBP-1 and ADRP. Re-sults TheresultsofELISAshowedthatserumTNF-αwas increased by 7 . 73 times in diabetic mice compared with normal mice. SREBP-1 and ADRP expressions were located in renal tubular cells. Again, it was con-firmed by Western blot that SREBP-1 precursor seg-ment, SREBP-1 mature segment and ADRP were re-spectively enhanced by 2. 31 times, 1. 74 times and 1. 72 times in diabetic mice in comparison with normal control mice . In addition , the data analysis revealed a positive correlation ( correlation coefficient 0. 914 ) be-tween serum TNF-αand renal ADRP expression. Con-clusion TheincreasedserumTNF-αmaybeoneof factors involved in renal lipid accumulation of diabe-tes.

Glycogen Synthase Kinase 3 Inactivation Induces Cell Senescence through Sterol Regulatory Element Binding Protein 1-Mediated Lipogenesis in Chang Cells

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.

Glycogen Synthase Kinase 3 Inactivation Induces Cell Senescence through Sterol Regulatory Element Binding Protein 1-Mediated Lipogenesis in Chang Cells

BACKGROUND: Enhanced lipogenesis plays a critical role in cell senescence via induction of expression of the mature form of sterol regulatory element binding protein 1 (SREBP1), which contributes to an increase in organellar mass, one of the indicators of senescence. We investigated the molecular mechanisms by which signaling molecules control SREBP1-mediated lipogenesis and senescence. METHODS: We developed cellular models for stress-induced senescence, by exposing Chang cells, which are immortalized human liver cells, to subcytotoxic concentrations (200 microM) of deferoxamine (DFO) and H2O2. RESULTS: In this model of stress-induced cell senescence using DFO and H2O2, the phosphorylation profile of glycogen synthase kinase 3alpha (GSK3alpha) and beta corresponded closely to the expression profile of the mature form of SREBP-1 protein. Inhibition of GSK3 with a subcytotoxic concentration of the selective GSK3 inhibitor SB415286 significantly increased mature SREBP1 expression, as well as lipogenesis and organellar mass. In addition, GSK3 inhibition was sufficient to induce senescence in Chang cells. Suppression of GSK3 expression with siRNAs specific to GSK3alpha and beta also increased mature SREBP1 expression and induced senescence. Finally, blocking lipogenesis with fatty acid synthase inhibitors (cerulenin and C75) and siRNA-mediated silencing of SREBP1 and ATP citrate lyase (ACL) significantly attenuated GSK3 inhibition-induced senescence. CONCLUSION: GSK3 inactivation is an important upstream event that induces SREBP1-mediated lipogenesis and consequent cell senescence.

Endoplasmic reticulum stress-induced fatty depositon in hepatocytes and the possible mechanism / 第二军医大学学报

Objective To observe the fatty deposition in thapsigargin-induced endoplasmic reticulum stress model in hepatocytes and to discuss the possible mechanism. Methods Hepatocytes (L02 cell and HepG2 cell line) were divided into control group and experimental group (treated with 1 μmol/L thapsigargin). Fatty deposition in the hepatocytes was observed by biochemical assay and oil red O staining. Real-time PCR was used to test the expression of SREBP-1c and LXRs mRNA. And Western blotting analysis was used to examine the expression of protein of GRP78, SREBP-1c and LXRs. Results Western blotting analysis showed that GRP78 protein expression in the experimental group was remarkably higher than that inthe control group (P<0. 05), indicating the successful establishment of the endoplasmic reticulum stress model in hepatocytes. The hepatocyte fatty deposition in the experimental group was significantly more than that in the control group 48 h after thapsigargin exposure(P<0. 01). The expression of SREBP-1c mRNA and protein in the experimental group was significantly higher than that in the control group (P<0. 05), and the expression of LXRs mRNA and proteinwas not significantly between the two groups. Conclusion Endoplasmic reticulum stress may induce hepatocyte fatty deposition throuth up-regulating SREBP-1c, and LXRs is not involved in the process.

Endoplasmic reticulum stress-induced fatty depositon in hepatocytes and the possible mechanism / 第二军医大学学报

Objective To observe the fatty deposition in thapsigargin-induced endoplasmic reticulum stress model in hepatocytes and to discuss the possible mechanism. Methods Hepatocytes (L02 cell and HepG2 cell line) were divided into control group and experimental group (treated with 1 μmol/L thapsigargin). Fatty deposition in the hepatocytes was observed by biochemical assay and oil red O staining. Real-time PCR was used to test the expression of SREBP-1c and LXRs mRNA. And Western blotting analysis was used to examine the expression of protein of GRP78, SREBP-1c and LXRs. Results Western blotting analysis showed that GRP78 protein expression in the experimental group was remarkably higher than that inthe control group (P<0. 05), indicating the successful establishment of the endoplasmic reticulum stress model in hepatocytes. The hepatocyte fatty deposition in the experimental group was significantly more than that in the control group 48 h after thapsigargin exposure(P<0. 01). The expression of SREBP-1c mRNA and protein in the experimental group was significantly higher than that in the control group (P<0. 05), and the expression of LXRs mRNA and proteinwas not significantly between the two groups. Conclusion Endoplasmic reticulum stress may induce hepatocyte fatty deposition throuth up-regulating SREBP-1c, and LXRs is not involved in the process.

Effects of dihydrotestosterone on the expression of SREBP-1c in human HaCaT keratinocytes / 中华皮肤科杂志

Obective To evaluate the effects of dihydrotestosterone (DHT) on the expression of sterol regulatory element-binding protein-1c (SREBP-1c) in human HaCaT keratinocytes.Methods HaCaT cells were cultured in vitro and classified into 4 groups,i.e.,control group receiving no treatment,DIIT group treated with 3 different concentrations (10,100,1000 nmol/L) of DHT,LY294002 plus DHT group treated with DHT of 100 nmol/L after 40-minute pretreatment with the PI3K inhibitor LY294002 of 50 μmol/L,PD98059 plus DHT group treated with DHT of 100 nmol/L after 40-minute pretreatment with the MEK inhibitor PD98059 of 50 μmol/L.After another 24-hour culture,real time PCR and Western blot were carried out to detect the expression of SREBP-1c mRNA and protein in HaCaT cells,respectively.Western blot was also performed to determine the phosphorylation levels of protein kinase B (AKT),extracellular signal-regulated kinase (ERK),p38 mitogen activated protein kinase and c-Jun N-terminal kinase (JNK) in the HaCaT cells.Results DHT could enhance the expression of SREBP-1c mRNA and protein in HaCaT cells in a concentration-dependent manner,and induce the phosphorylation of AKT and ERK,but not that of P38 or JNK.The expressions of SREBP-1c mRNA and protein were significantly decreased in HaCaT cells treated with LY294002 plus DHT (7.4780 ± 1.2638 vs.21.6170 ± 2.2759,t =9.406,P ＜ 0.05; 0.7113 + 0.0313 vs.2.2577 + 0.0601,t =39.498,P ＜ 0.05),but experienced no statistical changes in those treated with PD98059 and DHT(both P ＞ 0.05),compared with those treated with DHT only.Conclusion DHT can induce the expression of SREBP-1c mRNA and protein in HaCaT cells,likely via the PI3K/AKT signaling pathway.