Effects of K-877, a novel selective PPARα modulator, on small intestine contribute to the amelioration of hyperlipidemia in low-density lipoprotein receptor knockout mice

Peroxisome proliferator-activated receptor α (PPARα) is a well-known therapeutic target for treating hyperlipidemia. K-877 is a novel selective PPARα modulator (SPPARMα) that enhances PPARα transcriptional activity with high selectivity and potency, resulting in reduced plasma lipid levels. This study aimed to evaluate the effects of K-877 on hyperlipidemia in low-density lipoprotein receptor knockout (Ldlr−/−) mice, a mouse model of atherosclerosis. We revealed that K-877 administration significantly decreased plasma triglyceride (TG) and total cholesterol (TC) levels and increased plasma high-density lipoprotein cholesterol (HDL-C) levels in Ldlr−/− mice. K-877 administration to Ldlr−/− mice efficiently increased the gene expression of PPARα and its target genes related to fatty acid oxidation in the liver and small intestine. The same treatment significantly increased ATP-binding cassette a1 gene expression in the liver and small intestine and reduced Niemann Pick C1-like 1 gene expression in the small intestine, suggesting that K-877 administration induced HDL-C production in the liver and small intestine and reduced cholesterol absorption in the small intestine. In conclusion, K-877 administration had pronounced effects on the liver and small intestine in Ldlr−/− mice. K-877 is an attractive PPARα-modulating drug for treating hyperlipidemia that works equally well in both the liver and small intestine

Selective peroxisome proliferator-activated receptor-α modulator K-877 efficiently activates the peroxisome proliferator-activated receptor-α pathway and improves lipid metabolism in mice

Aims/IntroductionPeroxisome proliferator-activated receptor-α (PPARα) is a therapeutic target for hyperlipidemia. K-877 is a new selective PPARα modulator (SPPARMα) that activates PPARα transcriptional activity. The aim of the present study was to assess the effects of K-877 on lipid metabolism in vitro and in vivo compared with those of classical PPARα agonists.Materials and MethodsTo compare the effects of K-877 on PPARα transcriptional activity with those of the classical PPARα agonists Wy14643 (Wy) and fenofibrate (Feno), the cell-based PPARα transactivation luciferase assay was carried out. WT and Ppara−/− mice were fed with a moderate-fat (MF) diet for 6 days, and methionine–choline-deficient (MCD) diet for 4 weeks containing Feno or K-877.ResultsIn luciferase assays, K-877 activated PPARα transcriptional activity more efficiently than the classical PPARα agonists Feno and Wy. After being fed MF diet containing 0.001% K-877 or 0.2% Feno for 6 days, mice in the K-877 group showed significant increases in the expression of Ppara and its target genes, leading to marked reductions in plasma triglyceride levels compared with those observed in Feno-treated animals. These K-877 effects were blunted in Ppara−/− mice, confirming that K-877 activates PPARα. In further experiments, K-877 (0.00025%) and Feno (0.1%) equally improved the pathology of MCD diet-induced non-alcoholic fatty liver disease, with increased expression of hepatic fatty acid oxidation genes.ConclusionsThe present data show that K-877 is an attractive PPARα-modulating drug and can efficiently reduce plasma triglyceride levels, thereby alleviating the dysregulation of lipid metabolism

Octacosanol and policosanol prevent high-fat diet-induced obesity and metabolic disorders by activating brown adipose tissue and improving liver metabolism

Brown adipose tissue (BAT) is an attractive therapeutic target for treating obesity and metabolic diseases. Octacosanol is the main component of policosanol, a mixture of very long chain aliphatic alcohols obtained from plants. The current study aimed to investigate the effect of octacosanol and policosanol on high-fat diet (HFD)-induced obesity. Mice were fed on chow, or HFD, with or without octacosanol or policosanol treatment for four weeks. HFD-fed mice showed significantly higher body weight and body fat compared with chow-fed mice. However, mice fed on HFD treated with octacosanol or policosanol (HFDo/p) showed lower body weight gain, body fat gain, insulin resistance and hepatic lipid content. Lower body fat gain after octacosanol or policosanol was associated with increased BAT activity, reduced expression of genes involved in lipogenesis and cholesterol uptake in the liver, and amelioration of white adipose tissue (WAT) inflammation. Moreover, octacosanol and policosanol significantly increased the expression of Ffar4, a gene encoding polyunsaturated fatty acid receptor, which activates BAT thermogenesis. Together, these results suggest that octacosanol and policosanol ameliorate diet-induced obesity and metabolic disorders by increasing BAT activity and improving hepatic lipid metabolism. Thus, these lipids represent promising therapeutic targets for the prevention and treatment of obesity and obesity-related metabolic disorders

MafA Stability in Pancreatic β Cells Is Regulated by Glucose and Is Dependent on Its Constitutive Phosphorylation at Multiple Sites by Glycogen Synthase Kinase 3▿

Regulation of insulin gene expression by glucose in pancreatic β cells is largely dependent on a cis-regulatory element, termed RIPE3b/C1, in the insulin gene promoter. MafA, a member of the Maf family of basic leucine zipper (bZip) proteins, is a β-cell-specific transcriptional activator that binds to the C1 element. Based on increased C1-binding activity, MafA protein levels appear to be up-regulated in response to glucose, but the underlying molecular mechanism for this is not well understood. In this study, we show evidence supporting that the amino-terminal region of MafA is phosphorylated at multiple sites by glycogen synthase kinase 3 (GSK3) in β cells. Mutational analysis of MafA and pharmacological inhibition of GSK3 in MIN6 β cells strongly suggest that the rate of MafA protein degradation is regulated by glucose, that MafA is constitutively phosphorylated by GSK3, and that phosphorylation is a prerequisite for rapid degradation of MafA under low-glucose conditions. Our data suggest a new glucose-sensing signaling pathway in islet β cells that regulates insulin gene expression through the regulation of MafA protein stability

The Peroxisome Proliferator-Activated Receptor α (PPARα) Agonist Pemafibrate Protects against Diet-Induced Obesity in Mice

Peroxisome proliferator-activated receptor α (PPARα) is a therapeutic target for hyperlipidemia. Pemafibrate (K-877) is a new selective PPARα modulator activating PPARα transcriptional activity. To determine the effects of pemafibrate on diet-induced obesity, wild-type mice were fed a high-fat diet (HFD) containing pemafibrate for 12 weeks. Like fenofibrate, pemafibrate significantly suppressed HFD-induced body weight gain; decreased plasma glucose, insulin and triglyceride (TG) levels; and increased plasma fibroblast growth factor 21 (FGF21). However, compared to the dose of fenofibrate, a relatively low dose of pemafibrate showed these effects. Pemafibrate activated PPARα transcriptional activity in the liver, increasing both hepatic expression and plasma levels of FGF21. Additionally, pemafibrate increased the expression of genes involved in thermogenesis and fatty acid oxidation, including Ucp1, Cidea and Cpt1b in inguinal adipose tissue (iWAT) and the mitochondrial marker Elovl3 in brown adipose tissue (BAT). Therefore, pemafibrate activates thermogenesis in iWAT and BAT by increasing plasma levels of FGF21. Additionally, pemafibrate induced the expression of Atgl and Hsl in epididymal white adipose tissue, leading to the activation of lipolysis. Taken together, pemafibrate suppresses diet-induced obesity in mice and improves their obesity-related metabolic abnormalities. We propose that pemafibrate may be useful for the suppression and improvement of obesity-induced metabolic abnormalities

Enterohepatic Transcription Factor CREB3L3 Protects Atherosclerosis via SREBP Competitive Inhibition

動脈硬化発症を制御する転写因子の相互作用を発見. 京都大学プレスリリース. 2020-12-09.Background and Aims: cAMP responsive element-binding protein 3 like 3 (CREB3L3) is a membrane-bound transcription factor involved in the maintenance of lipid metabolism in the liver and small intestine. CREB3L3 controls hepatic triglyceride and glucose metabolism by activating plasma fibroblast growth factor 21 (FGF21) and lipoprotein lipase. In this study, we intended to clarify its effect on atherosclerosis. Methods: CREB3L3-deficifient, liver-specific CREB3L3 knockout, intestine-specific CREB3L3 knockout, both liver- and intestine-specific CREB3L3 knockout, and liver CREB3L3 transgenic mice were crossed with LDLR−/− mice. These mice were fed with a Western diet to develop atherosclerosis. Results: CREB3L3 ablation in LDLR−/− mice exacerbated hyperlipidemia with accumulation of remnant APOB-containing lipoprotein. This led to the development of enhanced aortic atheroma formation, the extent of which was additive between liver- and intestine-specific deletion. Conversely, hepatic nuclear CREB3L3 overexpression markedly suppressed atherosclerosis with amelioration of hyperlipidemia. CREB3L3 directly upregulates anti-atherogenic FGF21 and APOA4. In contrast, it antagonizes hepatic sterol regulatory element-binding protein (SREBP)-mediated lipogenic and cholesterogenic genes, and regulates intestinal liver X receptor-regulated genes involved in the transport of cholesterol. CREB3L3 deficiency results in the accumulation of nuclear SREBP proteins. Because both transcriptional factors share the cleavage system for nuclear transactivation, full-length CREB3L3 and SREBPs in the endoplasmic reticulum (ER) functionally inhibit each other. CREB3L3 promotes the formation of the SREBP-insulin induced gene 1 (SREBP-INSIG1) complex to suppress SREBPs for ER-Golgi transport, resulting in ER retention and inhibition of proteolytic activation at the Golgi, and vice versa. Conclusions: CREB3L3 has multi-potent protective effects against atherosclerosis owing to new mechanistic interaction between CREB3L3 and SREBPs under atherogenic conditions

Phase II study of the paclitaxel, cisplatin, 5-fluorouracil and leucovorin (TPFL) regimen in the treatment of advanced or metastatic gastric cancer

Advanced or metastatic gastric cancer, which is one of the most common malignancies in Korea, is difficult to cure by surgery alone and generally requires combination chemotherapy. Paclitaxel is active against gastric cancer and when combined with 5-fluorouracil/leucovorin and/or cisplatin is effective in the treatment of gastric cancer. We attempted to determine the effect and safety with the combination of paclitaxel with split cisplatin and 5-fluorouracil/leucovorin in advanced or metastatic gastric cancer. Patients with histologically-proven locally advanced/metastatic or recurrent gastric cancer with an ECOG performance status 0-2 were enrolled. The patients received 135 mg/m(2) of paclitaxel as a 3-h intravenous infusion on day 1 and 5-fluorouracil (1200 mg/m(2)) plus leucovorin (20 mg/m(2)) as an intravenous infusion over 12 h plus cisplatin (30 mg/m(2)) by continuous intravenous infusion on days 1-3, every 21 days. Between September 2003 and April 2005, 30 patients (26 evaluable patients) with a median age of 57 years (range 34-74) were enrolled and underwent 111 completed treatment cycles (a median of 3 cycles per patient). Of the evaluable patients, 12 patients showed a partial response and 8 patients had stable disease. The overall response rate was 46.2%. The median progression-free survival was 5.6 months (95% Cl. 3.76-7.4 months), and the median overall survival was 9.6 months (95% CI. 6.67-12.47 months). The hematologic and non-hematologic toxicities were tolerable. The grade III and IV hematologic toxicities were anemia (6.8%) and neutropenia (2.6%). Febrile neutropenia was observed in I patients and I cycle. Other hematologic toxicities and grade Ill and IV non-hematologic toxicities, except nausea (66.7%) and vomiting (33.3%) were uncommon and not severe. TPFL combination chemotherapy is effective and tolerable with acceptable toxicities in patients with advanced/metastatic, recurrent gastric cancer.Kim JG, 2007, CANCER CHEMOTH PHARM, V60, P863, DOI 10.1007/s00280-007-0433-8Pinto C, 2007, ANN ONCOL, V18, P510, DOI 10.1093/annonc/mdl459Shah MA, 2006, J CLIN ONCOL, V24, P5201, DOI 10.1200/JCO.2006.08.0887Van Cutsem E, 2006, J CLIN ONCOL, V24, P4991, DOI 10.1200/JCO.2006.06.8429Chao Y, 2006, BRIT J CANCER, V95, P159, DOI 10.1038/sj.bjc.6603225Wagner AD, 2006, J CLIN ONCOL, V24, P2903, DOI 10.1200/JCO.2005.05.0245Cho BC, 2006, ONCOL REP, V15, P621Jeung HC, 2006, ONCOLOGY-BASEL, V70, P63, DOI 10.1159/000091186Yeh KH, 2005, ONCOLOGY-BASEL, V69, P88, DOI 10.1159/000087304Omura GA, 2003, J CLIN ONCOL, V21, P2843, DOI 10.1200/JCO.2003.10.082Rothenberg ML, 2003, NAT REV CANCER, V3, P303, DOI 10.1038/nrc.1047Gadgeel SM, 2003, AM J CLIN ONCOL-CANC, V26, P37Louvet C, 2002, J CLIN ONCOL, V20, P4543, DOI 10.1200/JCO.2002.02.021Honecker F, 2002, ANTI-CANCER DRUG, V13, P497LEE HJ, 2002, GASTRIC CANCER, V5, P177CONSTENLA M, 2002, GASTRIC CANC, V5, P142Kollmannsberger C, 2000, BRIT J CANCER, V83, P458Vanhoefer U, 2000, J CLIN ONCOL, V18, P2648Yoo CH, 2000, BRIT J SURG, V87, P236Murad AM, 1999, AM J CLIN ONCOL-CANC, V22, P580Grem JL, 1999, BIOCHEM PHARMACOL, V58, P477Lokich JJ, 1999, CANCER, V85, P2347Rowinsky EK, 1999, CLIN CANCER RES, V5, P767Kim YH, 1999, CANCER, V85, P295Ajani JA, 1998, CANCER J SCI AM, V4, P269Cascinu S, 1998, ANTI-CANCER DRUG, V9, P307Bokemeyer C, 1997, ANTI-CANCER DRUG, V8, P396Glimelius B, 1997, ANN ONCOL, V8, P163Webb A, 1997, J CLIN ONCOL, V15, P261BOKEMEYER C, 1997, SEMIN ONCOL, V24Ychou M, 1996, EUR J CANCER, V32A, P1933Schipper DL, 1996, ANTI-CANCER DRUG, V7, P137Chang YF, 1996, CANCER, V77, P14KWAN HC, 1995, CANCER, V76, P2186ZANIBONI A, 1995, CANCER, V76, P1694VANHOEFER U, 1994, ANN ONCOL, V5, P850KIM NK, 1993, CANCER, V71, P3813OKADA Y, 1991, ANTI-CANCER DRUG, V2, P453JOHNSON PWM, 1991, BRIT J CANCER, V64, P603WILS JA, 1991, J CLIN ONCOL, V9, P827PREUSSER P, 1989, J CLIN ONCOL, V7, P1310POSNER MR, 1987, CANCER, V59, P15BELLIVEAU JF, 1986, CANCER TREAT REP, V70, P1215SALEM P, 1984, CANCER, V53, P837WEISS GB, 1983, CONTROL CLIN TRIALS, V4, P43SALEM P, 1978, CANCER TREAT REP, V62, P1553DREWINKO B, 1973, CANCER RES, V33, P3091

Hepatic rRNA Transcription Regulates High-Fat-Diet-Induced Obesity

Ribosome biosynthesis is a major intracellular energy-consuming process. We previously identified a nucleolar factor, nucleomethylin (NML), which regulates intracellular energy consumption by limiting rRNA transcription. Here, we show that, in livers of obese mice, the recruitment of NML to rRNA gene loci is increased to repress rRNA transcription. To clarify the relationship between obesity and rRNA transcription, we generated NML-null (NML-KO) mice. NML-KO mice show elevated rRNA level, reduced ATP concentration, and reduced lipid accumulation in the liver. Furthermore, in high-fat-diet (HFD)-fed NML-KO mice, hepatic rRNA levels are not decreased. Both weight gain and fat accumulation in HFD-fed NML-KO mice are significantly lower than those in HFD-fed wild-type mice. These findings indicate that rRNA transcriptional activation promotes hepatic energy consumption, which alters hepatic lipid metabolism. Namely, hepatic rRNA transcriptional repression by HFD feeding is essential for energy storage

ATF2 Interacts with β-Cell-enriched Transcription Factors, MafA, Pdx1, and Beta2, and Activates Insulin Gene Transcription*

Pancreatic β-cell-restricted expression of insulin is established through several critical cis-regulatory elements located in the insulin gene promoter region. The principal cis elements are A-boxes, E1, and C1/RIPE3b. The β-cell-enriched transcription factors Pdx1 and Beta2 bind to the A-boxes and E1 element, respectively. A β-cell-specific trans-acting factor binding to C1/RIPE3b (termed RIPE3b1 activator) was detected by electrophoretic mobility shift assay and has been identified as MafA, a member of the Maf family of basic leucine zipper (bZip) proteins. Here, ATF2, a member of the ATF/CREB family of basic leucine zipper proteins, was identified as a component of the RIPE3b1 activator. ATF2 alone was unable to bind to the C1/RIPE3b element but acquired binding capacity upon complex formation with MafA. ATF2 also interacted with Pdx1 and Beta2, and co-expression of ATF2, MafA, Pdx1, and Beta2 resulted in a synergistic activation of the insulin promoter. Immunohistochemical analysis of mouse pancreas tissue sections showed that ATF2 is enriched in islet endocrine cells, including β-cells. RNAi-mediated knockdown of MafA or ATF2 in the MIN6 β-cell line resulted in a significant decrease in endogenous levels of insulin mRNA. These data indicate that ATF2 is an essential component of the positive regulators of the insulin gene expression