Identification of differentially expressed genes and pathways in lipoprotein lipase gene heterozygous knockout mice through gene microarray analysis / 上海交通大学学报（医学版）

Objective • To screen the differentially expressed genes (DEGs) and pathways in the islet tissues of lipoprotein lipase (Lpl) gene heterozygous knockout (Lpl+/-) mice and wild type (WT) mice, and explore the molecular mechanism of pathogenesis of type 2 diabetes mellitus (T2DM) mediated by lipotoxicity. Methods • The islets of Lpl+/- mice and WT mice were isolated and purified. DEGs were screened by gene microarray analysis. Gene Ontology (GO) function analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of DEGs were performed. The expressions of key genes were verified by quantitative real-time PCR (qPCR). Results • A total of 187 DEGs were identified. GO functional analysis and KEGG pathway analysis showed that DEGs were mainly involved in the biological processes such as immune cell proliferation and differentiation, inflammatory signaling pathways and cell adhesion. Among the top 10 DEGs screened from Lpl+- mice and WT mice, gremlin 1 (Grem1) gene was closely related to the function of islet β cells, while the result of qPCR was consistent with that of gene microarray analysis. Conclusion • Multiple signaling pathways are involved in the process of T2DM mediated by lipotoxicity, which may lead to the dysfunction of islet β cells by inhibiting Grem1 expression.

MicroRNA-138 Suppresses Adipogenic Differentiation in Human Adipose Tissue-Derived Mesenchymal Stem Cells by Targeting Lipoprotein Lipase

PURPOSE: Adipogenic differentiation of adipose tissue-derived mesenchymal stem cells (AMSCs) is critical to many disease-related disorders, such as obesity and diabetes. Studies have demonstrated that miRNA-138 (miR-138) is closely involved in adipogenesis. However, the mechanisms affected by miR-138 remain unclear. This work aimed to investigate interactions between miR-138 and lipoprotein lipase (LPL), a key lipogenic enzyme, in AMSCs. MATERIALS AND METHODS: Human AMSCs (hAMSCs) isolated from human abdomen tissue were subjected to adipogenic differentiation medium. Quantitative real-time polymerase chain reaction and Western blot assay were applied to measure the expressions of miR-138, LPL, and the two adipogenic transcription factors cytidine-cytidine-adenosine-adenosine-thymidine enhancer binding protein alpha (C/EBPα) and peroxisome proliferator-activated receptor gamma (PPARγ). The relationship between miR-138 and LPL was predicted utilizing the miRTarBase database and validated by dual luciferase reporter assay. RESULTS: Showing increases in C/EBPα and PPARγ expression levels, hAMSCs were induced into adipogenic differentiation. During adipogenesis of hAMSCs, miR-138 expression was significantly downregulated. Overexpression of miR-138 by transfection inhibited hAMSCs adipogenic differentiation in vitro. Mechanically, LPL was a target of miR-138. LPL expression was upregulated during adipogenesis of hAMSCs, and this upregulation was reversed by miR-138 overexpression. Functionally, silencing of LPL by transfection exerted similar inhibition of the expressions of C/EBPα and PPARγ. Meanwhile, LPL ectopic expression was able to partly abolish the suppressive effect of miR-138 overexpression on adipogenic differentiation of hAMSCs. CONCLUSION: Upregulation of miR-138 inhibits adipogenic differentiation of hAMSCs by directly downregulating LPL.

Inhibitory effects of Capsicum annuum L. water extracts on lipoprotein lipase activity in 3T3-L1 cells

Obesity, an intractable metabolic disease, currently has no medical treatment without side effects, so studies have been actively carried out to find natural compounds that have anti-obesity activity with minimum side effects. In this study, the anti-obesity effects of water extracts of seven Capsicum annuum L. varieties being Putgochu (Pca), Oyee gochu (Oca), Kwari putgochu (Kca), Green pepper (Gca), Yellow paprika (Yca), Red paprika (Rca) and Cheongyang gochu (Cca), were examined through the evaluation of lipoprotein lipase (LPL) mRNA expression level in 3T3-L1 cells (mouse pre-adipocytes). After capsaicin elimination by chloroform defatting, freeze-dried powder of Cca was treated to 3T3-L1 cells and anti-obesity effects were examined by determining the LPL mRNA level using the RT-PCR method. Of the primary fractions, only proven fractions underwent secondary and tertiary refractionating to determine anti-obesity effects. From seven different Capsicum annuum L., there was a significant decrease of the LPL mRNA expression level of 50.9% in Cca treatment compared to the control group. A significant decrease of the LPL mRNA expression level was shown in primary fractions (Fr) 5 (36.2% decrease) and 6 (30.5% decrease) of the Cca water extracts. Due to the impurities checked by UPLC chromatography, Fr 5 and 6 were refractionated to determine the LPL mRNA expression level. Treatment of Fr 6-6 (35.8% decrease) and Fr 5-6 (35.3% decrease) showed a significant decrease in the LPL mRNA expression level. When analyzed using UPLC, major compounds of Fr 6-6 and Fr 5-6 were very similar. Subsequently, we refractionated Fr 6-6 and Fr 5-6 to isolate the major peak for structure elucidation. Treatment of Fr 5-6-1 (26.6% decrease) and Fr 6-6-1 (29.7% decrease) showed a significant decrease in the LPL mRNA expression level. Consequently, the fractions may have a possibility to ameliorate obesity through the decrease of the LPL mRNA expression level.

The role of Akt and Lpl in formation of nonalcoholic steatohepatitis in rat with a fat-rich diet / 中国康复理论与实践

@#ObjectiveTo investigate the role of serine/threonine kinase (Akt) and lipoprotein lipase (Lpl) in formation of nonalcoholic steatohepatitis (NASH) in rat with a fat-rich diet.Methods40 male Wistar rats were randomly divided into the 8-week-rich-fat group (n=10), 8-week-common-diet control group (n=10), 12-week-rich-fat group (n=10) and 12-week-common-diet control group (n=10). The lipid, cholesterol, glucose and insulin were examined, insulin resistance index (IRI) and insulin sensitivity index (ISI) were calculated, the expression of Akt and Lpl were detected with immunohistochemical method and morphological changes of liver were observed by transmission electron microscope (TEM).ResultsNASH was formed in each rat of 8-week-rich-fat group with characteristics of individual obese, increased liver volume, full and clear contour, gray-yellowish luster, greasy section and crisp quality. And it was accompanied by high lipoidemia (HL), liver fat cell denaturation, inflammatory cell infiltration in liver lobuler and cell death in liver. The expression of Akt was obviously reduced and the expression of Lpl was obviously weakened in liver. Lipid, cholesterol, glucose and insulin and IRI were gradually advancing. ISI was reducing and the insulin resistance formed. The data of fat-rich diet groups was significantly different with that of common-diet control groups (P<0.0001).Conclusion Steatohepatitis and insulin resistance can form in rat by feeding with rich-fat diet for 8 weeks. It causes the insulin and Lpl activeness reducing, and steatolysis barrier.

Progress on the drugs for regulating high-density lipoprotein / 中国临床药理学与治疗学

Atherosclerosis (AS) is pathologically important basis of many kinds of coronary atherosclerosis disease (CAD). It can be substantially protected by raising high-density lipoprotein (HDL).In view of mechanism, drugs for raising HDL include: cholesterol ester transfer protein inhibitors, peroxisomal proliferator-activated receptor agonists, liver X-activated receptor agonists, farnesoid X receptor antagonists or agonists, lipoprotein lipase activators, niacin, and phenytoin and lecin : cholesterol acyltransferase activators, etc. This review aimed to the progress of drugs for regulating high-density lipoprotein and their mechanism, in view of clinical and preclinical aspects.

Polymorphisms at the Lipoprotein Lipase Gene: Possible Associations with Coronary Artery Disease and Blood Lipid Levels in Koreans / 대한임상병리학회지

BACKGROUND: Lipoprotein lipase (LPL) gene polymorphisms have been found associated with coronary artery disease (CAD) and lipid levels, but their impact is less clearly established. The analysis of associations of LPL gene polymorphisms with CAD and lipid levels in Koreans was investigated. METHODS: Analysis of PvuII (intron 6), HindIII (intron 8), and Ser447-Ter (exon 9) polymorphisms of LPL gene were performed using restriction enzyme digestion of amplified DNA products and lipid levels were analyzed in healthy control subjects (n=228) and patients with CAD (n=166). RESULTS: PvuII, HindIII, and Ser447-Ter sites were in strong linkage disequilibrium. No statistical differences in the genotypic frequencies of PvuII, HindIII, and Ser447-Ter polymorphisms were observed between control and CAD groups. P2P2 genotype had higher triglyceride level in CAD group and lower HDL-cholesterol level in control group than the other genotypes (P1P1, P1P2). H2H2 genotype had higher triglyceride level in CAD group and lower HDL-cholesterol level in control group than the other genotypes (H1H1, H1H2). CONCLUSIONS: Genotypes of LPL PvuII, HindIII, and Ser447-Ter polymorphisms were not associated with CAD. Individuals with P2P2 and H2H2 genotypes, however, had higher triglyceride and lower HDL-cholesterol levels that is known to be the most commmon dyslipidaemia in CAD patients.

Incidence of Lipoprotein Lipase Gene Polymorphism and Correlation with Severity of Coronary Artery Disease in Korean

BACKGROUND: Lipoprotein lipase(LPL) is a key enzyme in the metabolism of serum triglyceride(TG) which is utilized in the peripheral tissue as free fatty acid and stored in adipose tissue. LPL gene consists of 10 exons which encode 475 amino acids and more than 9 LPL gene polymorphisms have been reported. LPL gene polymorphism is related to lipids level and the severity of atherosclerosis in coronary artery disease. In Korea, LPL polymorphism has not been reported yet. The purpose of this study is to konw the incidences of LPL gene polymorphism and it's relationship with blood lipids level and the severity of atherosclerosis. METHODS: Subjects were divided into three groups; normal controls(n=50), coronary artery disease(CAD, n=51) and cerebrovascular disease(CVD, n=52). The PCR- amplified genomic DNA from peripheral white blood cell was analyzed with restriction fragment length polymorphism(RFLP) by two different restriction enzymes(Pvu II, Hind III). RESULTS: Total cholesterol(TC) was higher in CVD than in controls and CAD (203+/-60mg/dl vs 188+/-37, 167+/-42, p<0.01). Triglyceride(TG) was also elevated in CAD(166+/-65mg/dl vs 122+/-62 in controls, p<0.05). HDL cholesterol(HDL-C) was higher in controls than in CVD and CAD(49+/-9mg/dl vs 36+/-10, 44+/-9, p<0.05). The incidence of Hind III RFLP and Pvu II RFLP was not different among groups. There was no correlation between LPL gene RFLP and lipid profile. There was no correlation between LPL gene RFLP and severity of coronary arterial stenosis. The incidence of Hind III RFLP (-/-) homozygotes was lower in Korean than in other country(5% vs 7-10%). The incidence of Pvu II RFLP (-/-) homozygotes was lower in Korean than in other country(10.3% vs 18-29%). CONCLUSIONS: The LPL gene mutations in intron 6 and 8 have no direct effects on the lipid profiles and the severity of coronary artery disease. Although LPL is a key enzyme in TG metabolism, two mutations in this study could not change the activity of LPL, nor were a marker linked to other site of mutation(s). The mutation(s) in exon which encode amino acid for enzyme activity should be detected to dissect the pathphysiologic mechanism in the atherogenesis.