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.

Background & 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 up-regulates 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 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.

Mice overexpressing the nuclear form of CREBH mainly in the liver (CREBH-Tg) showed suppression of high-fat high-sucrose (HFHS) diet-induced obesity accompanied by an increase in plasma fibroblast growth factor 21 (FGF21) levels. CREBH overexpression induced browning in inguinal white adipose tissue (WAT) and whole-body energy expenditure, which was canceled in Fgf21 À/À mice. Deficiency of FGF21 in CREBH-Tg mice mostly canceled the improvement of obesity, but the suppression of inflammation of epidermal WAT, amelioration of insulin resistance, and improvement of glucose metabolism still sustained. Kisspeptin 1 (Kiss1) was identified as a novel hormone target for CREBH to explain these FGF21-independent effects of CREBH. Knockdown of Kiss1 in HFHS-fed CREBH-Tg Fgf21 À/À mice showed partially canceled improvement of glucose metabolism. Taken together, we propose that hepatic CREBH pleiotropically improves diet-induced obesity-mediated dysfunctions in peripheral tissues by improving systemic energy metabolism in FGF21-dependent and FGF21-independent mechanisms.

cAMP responsive element-binding protein H (CREBH) is a hepatic transcription factor to be activated during fasting. We generated CREBH knock-in flox mice, and then generated liver-specific CREBH transgenic (CREBH L-Tg) mice in an active form.CREBH L-Tg mice showed a delay in growth in the postnatal stage. Plasma growth hormone (GH) levels were significantly increased in CREBH L-Tg mice, but plasma insulin-like growth factor 1 (IGF1) levels were significantly decreased, indicating GH resistance. In addition, CREBH overexpression significantly increased hepatic 2 of 14 | NAKAGAWA et Al.

Correspondence; 29 ynaka@inm.u-toyama.ac.jp 30 and 31 hshimano@md.tsukuba.ac.jp 32 33 34 Summary 35CREB3L3 is a membrane-bound transcription factor to maintain lipid metabolism in the liver 36 and small intestine. CREB3L3 ablation in Ldlr −/− mice exacerbated hyperlipidemia with 37 remnant ApoB-containing lipoprotein accumulation, developing enhanced aortic atheroma 38 formation, whose extent was additive between liver-and intestine-specific deletion. 39 Conversely, hepatic nuclear CREB3L3 overexpression markedly suppressed atherosclerosis 40 with amelioration of hyperlipidemia. CREB3L3 directly upregulates anti-atherogenic FGF21 41 and ApoA4, whereas antagonizes hepatic SREBP-mediated lipogenic and cholesterogenic 42 genes and regulates LXR-regulated genes involved in intestinal transport of cholesterol. 43 CREB3L3 deficiency accumulates nuclear SREBP proteins. Because both transcriptional 44 factors share the cleavage system for nuclear transactivation, full-length CREB3L3 and 45 SREBPs on endoplasmic reticulum (ER) functionally inhibit each other. CREB3L3 46 competitively antagonizes SREBPs for ER-Golgi transport, resulting in ER retention and 47 proteolytic activation inhibition at Golgi, and vice versa. Collectively, due to this new 48 mechanistic interaction between CREB3L3 and SREBPs under atherogenic conditions, 49 CREB3L3 has multi-potent protective effects against atherosclerosis. 50 51 52 53 54cAMP responsive element-binding protein 3 like 3 (Creb3l3) is expressed only in 55 liver and intestinal cells (Lee et al. , 2011), where the CREB3L3 protein localizes in the 56 endoplasmic reticulum (ER) and is transported to the Golgi apparatus and nucleus (Lee et 57 al. , 2011, Omori et al. , 2001, Zhang et al. , 2006. Nuclear expression of the active form of 58 CREB3L3 in the nucleus is increased under fasting, consistent with the finding that Creb3l3 59 mRNA expression is higher during fasting than refeeding (Danno et al. , 2010). CREB3L3 60 reduces plasma triglyceride (TG) levels by increasing hepatic expression of apolipoprotein-61 encoding genes, such as apolipoprotein A4 (Apoa4), Apoa5, and Apoc2 (Lee et al. , 2011); 62 these activate blood lipoprotein lipase (LPL) activity. Creb3l3 −/− mice exhibit massive hepatic 63 lipid metabolite accumulation and significantly increased plasma TG levels, or nonalcoholic 64 steatohepatitis when fed an atherogenic high-fat diet (Luebke-Wheeler et al. , 2008). Apoa4 65 regulates HDL metabolism by activating lecithin-cholesterol acyltransferase, a key enzyme 66 involved in cholesterol transfer to newly synthesized HDL particles (Chen and Albers, 1985, 67 Steinmetz and Utermann, 1985), stimulating cholesterol efflux from macrophages (Fournier 68 et al. , 2000) and activating receptor-mediated uptake of HDL by hepatocytes (Steinmetz et 69 al. , 1990). Apoa4-overexpressed mice prevent atherosclerosis development (Cohen et al. , 70 1997, Duverger et al. , 1996, Ostos et al. , 2001. 71 CREB3L3 and peroxisome proliferator-activated receptor alpha (PPARα) 72...