In this study, we defined the role of peroxisome proliferator-activated receptor ␤͞␦ (PPAR␦) in metabolic homeostasis by using subtype selective agonists. Analysis of rat L6 myotubes treated with the PPAR␦ subtype-selective agonist, GW501516, by the Affymetrix oligonucleotide microarrays revealed that PPAR␦ controls fatty acid oxidation by regulating genes involved in fatty acid transport, ␤-oxidation, and mitochondrial respiration. Similar PPAR␦-mediated gene activation was observed in the skeletal muscle of GW501516-treated mice. Accordingly, GW501516 treatment induced fatty acid ␤-oxidation in L6 myotubes as well as in mouse skeletal muscles. Administration of GW501516 to mice fed a high-fat diet ameliorated diet-induced obesity and insulin resistance, an effect accompanied by enhanced metabolic rate and fatty acid ␤-oxidation, proliferation of mitochondria, and a marked reduction of lipid droplets in skeletal muscles. Despite a modest body weight change relative to vehicle-treated mice, GW501516 treatment also markedly improved diabetes as revealed by the decrease in plasma glucose and blood insulin levels in genetically obese ob͞ob mice. These data suggest that PPAR␦ is pivotal to control the program for fatty acid oxidation in the skeletal muscle, thereby ameliorating obesity and insulin resistance through its activation in obese animals.obesity ͉ insulin resistance ͉ thermogenesis ͉ pancreatic ␤-cell ͉ PGC-1␣

A Wnt coreceptor low-density lipoprotein receptor-related protein 5 (LRP5) plays an essential role in bone accrual and eye development. Here, we show that LRP5 is also required for normal cholesterol and glucose metabolism. The production of mice lacking LRP5 revealed that LRP5 deficiency led to increased plasma cholesterol levels in mice fed a high-fat diet, because of the decreased hepatic clearance of chylomicron remnants. In addition, when fed a normal diet, LRP5-deficient mice showed a markedly impaired glucose tolerance. The LRP5-deficient islets had a marked reduction in the levels of intracellular ATP and Ca 2؉ in response to glucose, and thereby glucoseinduced insulin secretion was decreased. The intracellular inositol 1,4,5-trisphosphate (IP3) production in response to glucose was also reduced in LRP5؊͞؊ islets. Real-time PCR analysis revealed a marked reduction of various transcripts for genes involved in glucose sensing in LRP5؊͞؊ islets. Furthermore, exposure of LRP5؉͞؉ islets to Wnt-3a and Wnt-5a stimulates glucose-induced insulin secretion and this stimulation was blocked by the addition of a soluble form of Wnt receptor, secreted Frizzled-related protein-1. In contrast, LRP5-deficient islets lacked the Wnt-3a-stimulated insulin secretion. These data suggest that Wnt͞LRP5 signaling contributes to the glucose-induced insulin secretion in the islets.and LRP6 are coreceptors involved in the Wnt signaling pathway (1-6). The Wnt signaling pathway plays a pivotal role in embryonic development (7,8) and oncogenesis (9) through various signaling molecules including Frizzled receptors (10), recently characterized LRP5 and LRP6 (1-6), and Dickkopf proteins (4, 6). In addition, the Wnt signaling is also involved in adipogenesis by negatively regulating adipogenic transcription factors (Tcfs) (11). Although Wnt signaling has been characterized in both developmental and oncogenic processes, little is known about its function in the normal adult.Recent studies have revealed that loss of function mutations in the LRP5 gene cause the autosomal recessive disorder osteoporosis-pseudoglioma syndrome (12). LRP5 is expressed in osteoblasts and transduces Wnt signaling via the canonical pathway, thereby modulating bone accrual development (12, 13). A point mutation in a ''propeller'' motif in LRP5 causes a dominant-positive high bone density by impairing the action of a normal antagonist of the Wnt pathway, Dickkopf, thereby increasing Wnt signaling (14,15). In addition, the human LRP5 gene is mapped within the region (IDDM4) linked to type 1 diabetes on chromosome 11q13 (16).In previous studies, we and others showed that LRP5 is highly expressed in many tissues, including hepatocytes and pancreatic beta cells (17,18). We also showed that LRP5 can bind apolipoprotein E (apoE) (18). This finding raises the possibility that LRP5 plays a role in the hepatic clearance of apoE-containing chylomicron remnants, a major plasma lipoprotein carrying diet-derived cholesterol.To evaluate the in vivo roles of LRP5, we generated LRP...

Acetate is activated to acetyl-CoA by acetyl-CoA synthetase 2 (AceCS2), a mitochondrial enzyme. Here, we report that the activation of acetate by AceCS2 has a specific and unique role in thermogenesis during fasting. In the skeletal muscle of fasted AceCS2(-/-) mice, ATP levels were reduced by 50% compared to AceCS2(+/+) mice. Fasted AceCS2(-/-) mice were significantly hypothermic and had reduced exercise capacity. Furthermore, when fed a low-carbohydrate diet, 4-week-old weaned AceCS2(-/-) mice also exhibited hypothermia accompanied by sustained hypoglycemia that led to a 50% mortality. Therefore, AceCS2 plays a significant role in acetate oxidation needed to generate ATP and heat. Furthermore, AceCS2(-/-) mice exhibited increased oxygen consumption and reduced weight gain on a low-carbohydrate diet. Our findings demonstrate that activation of acetate by AceCS2 plays a pivotal role in thermogenesis, especially under low-glucose or ketogenic conditions, and is crucially required for survival.

Acetyl-CoA synthetase 2 (AceCS2) produces acetylCoA for oxidation through the citric acid cycle in the mitochondrial matrix. AceCS2 is highly expressed in the skeletal muscle and is robustly induced by fasting. Quantification of AceCS2 transcripts both in C2C12 and human myotubes indicated that fasting-induced AceCS2 gene expression appears to be independent on insulin action. Characterization of 5 -flanking region of the mouse AceCS2 gene demonstrates that Krü ppel-like factor 15 (KLF15) plays a key role in the trans-activation of the AceCS2 gene. Deletion and mutation analyses of AceCS2 promoter region revealed that the most proximal KLF site is a curtail site for the trans-activation of the AceCS2 gene by KLF15. Using Sp-null Drosophila SL2 cells, we showed that the combination of KLF15 and Sp1 resulted in a synergistic activation of the AceCS2 promoter. Mutation analyses of three GC-boxes in the AceCS2 promoter indicated that the GC-box, located 8 bases downstream of the most proximal KLF15 site, is the most important GC-box in the synergistic trans-activation of the AceCS2 gene by KLF15 and Sp1. GST pull-down assays showed that KLF15 interacts with Sp1 in vitro. Quantification of various KLF transcripts revealed that 48 h fasting robustly induced the KLF15 transcripts in the skeletal muscle. Together with the trans-activation of the AceCS2 promoter, it is suggested that fasting-induced AceCS2 expression is largely contributed by KLF15. Furthermore, KLF15 overexpression induced the levels of AceCS2 transcripts both in myoblasts and in myotubes, indicating that AceCS2 gene expression in vivo is indeed induced by KLF15.Acetyl-CoA is an important intermediate in various metabolic pathways including fatty acid and cholesterol biosynthesis and the energy production by the citric acid cycle. There are several enzymes that generate acetyl-CoA in the mammals, including pyruvate dehydrogenase, which converts pyruvate to acetyl-CoA without generating free acetate. The degradation of fatty acid via ␤-oxidation system also produces acetyl-CoA as an end product. Although acetate is not an essential source of acetyl-CoA in animals, the enzymatic ligation for the production of acetyl-CoA from acetate and CoA is a key reaction in the catabolism of acetate formed by several conditions including bacterial fermentation in the colon, oxidation of ingested ethanol in the liver. Acetyl-CoA synthetase (AceCS, 1 EC 6.2.1.1) is an enzyme that catalyzes the production of acetyl-CoA from acetate and CoA. In particular, this enzyme plays a key role in the nervous system for recycling of acetate released by acetylcholine esterase for the formation and release of acetylcholine in cholinergic nerve terminals.There are two AceCSs with similar enzymatic properties in mammals: one designated AceCS1 is a cytosolic enzyme and the other, designated AceCS2, is a mitochondrial matrix enzyme (1). Localized in the cytoplasm, AceCS1 provides acetylCoA for the synthesis of fatty acids and cholesterol. In contrast, AceCS2 produces acetyl-CoA for oxida...

Our study emphasizes the importance of differentiating MCL, FL and MALT of LP in evaluating prognosis and hence the most suitable therapeutic regimen.

Bendamustine is a unique cytotoxic agent that has demonstrated efficacy in the treatment of indolent B-cell non-Hodgkin lymphomas (B-NHLs). In this multicenter phase II trial, the efficacy and safety of bendamustine were evaluated in Japanese patients with relapsed or refractory indolent B-NHL or mantle-cell lymphoma (MCL). Patients received bendamustine (120 mg ⁄ m 2 ) on days 1-2 of a 21-day cycle, for up to six cycles. The primary endpoint was the overall response rate (ORR) as assessed by an extramural committee according to International Workshop Response Criteria (IWRC). Secondary endpoints included complete response (CR) rate, ORR according to Revised Response Criteria (revised RC), progression-free survival (PFS), and safety. Fifty-eight patients with indolent B-NHL and 11 with MCL were enrolled. By IWRC, bendamustine produced an ORR of 91% (95% confidence interval [CI], 82-97%; 90% and 100% in patients with indolent B-NHL and MCL, respectively), with a CR rate of 67% (95% CI, 54-78%). ORR and CR rates according to revised RC were 93% (95% CI, 84-98%) and 57% (95% CI, 44-68%), respectively. After a median follow-up of 12.6 months, median PFS had not been reached. Estimated PFS rates at 1 year were 70% and 90% among indolent B-NHL and MCL patients, respectively. Bendamustine was generally well tolerated. Reversible myelosuppression, including grade 3 ⁄ 4 leukopenia (65%) and neutropenia (72%), was the most clinically significant toxicity observed. Common non-hematologic toxicities included mild gastrointestinal events and fatigue. These results demonstrate the high efficacy and tolerability of single-agent bendamustine in relapsed patients with indolent B-NHL or MCL histologies.

Cytosolic acetyl-CoA synthetase (AceCS1) activates acetate to supply the cells with acetyl-CoA for lipid synthesis. The cDNA for the mammalian AceCS1 has been isolated recently, and the mRNA was shown to be negatively regulated by sterols in cultured cells. In the current study, we describe the molecular mechanisms directing the sterol-regulated expression of murine AceCS1 by cloning and functional studies of the 5-flanking region of the AceCS1 gene. An AceCS1 promoter-reporter gene (ϳ2.1 kilobase pairs) was negatively regulated when sterols were added to the medium of cultured cells, and the promoter was markedly induced by co-transfection of a plasmid that expresses the transcriptionally active nuclear form of either sterol regulatory element-binding protein (SREBP)-1a or -2 in HepG2 cells. Sequence analysis suggested that the AceCS1 promoter contains an E-box, two putative CCAAT-boxes, eight sterol regulatory element (SRE) motifs, and six GC-boxes. Gel shift assays demonstrated that all eight SRE motifs bound purified SREBP-1a in vitro with similar affinity. Luciferase reporter gene assays revealed that sterol regulation was critically dependent on three closely spaced SRE motifs and an adjacent GC-box. However, mutation of two putative upstream CCAAT-boxes did not affect SREBP dependent activation. Electrophoretic mobility "supershift" analyses confirmed that both Sp1 and Sp3 bound to the critical GC-box. In addition, transfection studies in Drosophila SL2 cells demonstrated that SREBP synergistically activated the AceCS1 promoter along with Sp1 or Sp3 but not with nuclear factor-Y.

BackgroundPrimary adrenal lymphoma (PAL) is an extremely rare subtype of extranodal non-Hodgkin’s lymphoma. Some researchers have reported some of the characteristics of PAL and its association with poor prognosis; however, the clinicopathological features of PAL remain to be elucidated.MethodsFrom 2008 to 2011 we experienced seven cases of PAL in our institutions. We retrospectively analyzed the clinical and pathological features of these patients.ResultsThe patients ranged in age from 50 to 85 years, with a median of 71 years. The overall male:female ratio was 6:1. All seven patients were diagnosed with diffuse large B-cell lymphoma (DLBCL) pathologically. Bilateral adrenal involvement was confirmed in five patients. The median largest tumor diameter at diagnosis was 58 mm. The Ki-67 index was generally high (>70%). All patients were treated with rituximab-containing chemotherapy, and central nervous system (CNS) prophylaxis was conducted for three patients. One patient with CNS involvement at the time of the diagnosis also received whole-brain radiation. The overall survival rate at two years was 57% (median follow-up; 24.8 months). It is noteworthy that the three patients who received a full course of the rituximab-containing regimen and CNS prophylaxis are currently alive without disease relapse, and that none of the seven patients died due to progression of lymphoma.ConclusionsPrimary adrenal DLBCL can be a clinically aggressive disease entity. Rituximab-containing chemotherapy combined with CNS prophylaxis could be a reasonable option for the treatment of PAL; however, analyses of more PAL cases are needed for the establishment of this strategy.