Yuya Fujishima

Short-term effects of liraglutide on visceral fat adiposity, appetite, and food preference: a pilot study of obese Japanese patients with type 2 diabetes

BackgroundTo examine the effects of liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, on visceral fat adiposity, appetite, food preference, and biomarkers of cardiovascular system in Japanese patients with type 2 diabetes.MethodsThe study subjects were 20 inpatients with type 2 diabetes treated with liraglutide [age; 61.2 ± 14.0 years, duration of diabetes; 16.9 ± 6.6 years, glycated hemoglobin (HbA1c); 9.1 ± 1.2%, body mass index (BMI); 28.3 ± 5.2 kg/m2, mean ± SD]. After improvement in glycemic control by insulin or oral glucose-lowering agents, patients were switched to liraglutide. We assessed the estimated visceral fat area (eVFA) by abdominal bioelectrical impedance analysis, glycemic control by the 75-g oral glucose tolerance test (OGTT) and eating behavior by the Japan Society for the Study of Obesity questionnaire.ResultsTreatment with liraglutide (dose range: 0.3 to 0.9 mg/day) for 20.0 ± 6.4 days significantly reduced waist circumference, waist/hip ratio, eVFA. It also significantly improved the scores of eating behavior, food preference and the urge for fat intake and tended to reduce scores for sense of hunger. Liraglutide increased serum C-peptide immunoreactivity and disposition index.ConclusionsShort-term treatment with liraglutide improved visceral fat adiposity, appetite, food preference and the urge for fat intake in obese Japanese patients with type 2 diabetes.

Positive Feedback Regulation Between Adiponectin and T-Cadherin Impacts Adiponectin Levels in Tissue and Plasma of Male Mice

Adiponectin (Adipo), a multimeric adipocyte-secreted protein abundant in the circulation, is implicated in cardiovascular protective functions. Recent work documented that Adipo locally associates with responsive tissues through interactions with T-cadherin (Tcad), an atypical, glycosylphosphatidylinositol (GPI)-anchored cadherin cell surface glycoprotein. Mice deficient for Tcad lack tissue-associated Adipo, accumulate Adipo in the circulation, and mimic the Adipo knockout (KO) cardiovascular phenotype. In reverse, Tcad protein is visibly reduced from cardiac tissue in Adipo-KO mice, suggesting interdependent regulation of the 2 proteins. Here, we evaluate the effect of Adipo on Tcad protein expression. Adipo and Tcad proteins were colocalized in aorta, heart, and skeletal muscle. Adipo positively regulated levels of Tcad protein in vivo and in endothelial cell (EC) cultures. In Tcad-KO mice, binding of endogenous and exogenously administered Adipo to cardiovascular tissues was dramatically reduced. Consistently, knockdown of Tcad in cultured murine vascular ECs significantly diminished Adipo binding. In search for a possible mechanism, we found that enzymatic cleavage of Tcad with phosphatidylinositol-specific phospholipase C increases plasma Adipo while decreasing tissue-bound levels. Similarly, pretreatment of cultured ECs with serum containing Adipo attenuated phosphatidylinositol-specific phospholipase C-mediated Tcad cleavage. In vivo administration of adenovirus producing Adipo suppressed plasma levels of GPI phospholipase D, the endogenous cleavage enzyme for GPI-anchored proteins. In conclusion, our data show that both circulating and tissue-bound Adipo levels are dependent on Tcad and, in reverse, regulate tissue Tcad levels through a positive feedback loop that operates by suppressing phospholipase-mediated Tcad release from the cell surface.

Efficacy of liraglutide, a glucagon-like peptide-1 (GLP-1) analogue, on body weight, eating behavior, and glycemic control, in Japanese obese type 2 diabetes

BackgroundWe recently reported that short-term treatment with liraglutide (20.0 ± 6.4 days) reduced body weight and improved some scales of eating behavior in Japanese type 2 diabetes inpatients. However, it remained uncertain whether such liraglutide-induced improvement is maintained after discharge from the hospital. The aim of the present study was to determine the long-term effects of liraglutide on body weight, glycemic control, and eating behavior in Japanese obese type 2 diabetics.MethodsPatients with obesity (body mass index (BMI) >25 kg/m2) and type 2 diabetes were hospitalized at Osaka University Hospital between November 2010 and December 2011. BMI and glycated hemoglobin (HbA1c) were examined on admission, at discharge and at 1, 3, and 6 months after discharge. For the liraglutide group (BMI; 31.3 ± 5.3 kg/m2, n = 29), patients were introduced to liraglutide after correction of hyperglycemic by insulin or oral glucose-lowering drugs and maintained on liraglutide after discharge. Eating behavior was assessed in patients treated with liraglutide using The Guideline For Obesity questionnaire issued by the Japan Society for the Study of Obesity, at admission, discharge, 3 and 6 months after discharge. For the insulin group (BMI; 29.1 ± 3.0 kg/m2, n = 28), each patient was treated with insulin during hospitalization and glycemic control maintained by insulin after discharge.ResultsLiraglutide induced significant and persistent weight loss from admission up to 6 months after discharge, while no change in body weight after discharge was noted in the insulin group. Liraglutide produced significant improvements in all major scores of eating behavior questionnaire items and such effect was maintained at 6 months after discharge. Weight loss correlated significantly with the decrease in scores for recognition of weight and constitution, sense of hunger, and eating style.ConclusionLiraglutide produced meaningful long-term weight loss and significantly improved eating behavior in obese Japanese patients with type 2 diabetes.

Gene expression levels of S100 protein family in blood cells are associated with insulin resistance and inflammation (Peripheral blood S100 mRNAs and metabolic syndrome).

OBJECTIVE Visceral fat obesity is located upstream of metabolic syndrome and atherosclerotic diseases. Accumulating evidences indicate that several immunocytes including macrophages infiltrate into adipose tissue and induce chronic low-grade inflammation. We recently analyzed the association between visceral fat adiposity and the gene expression profile in peripheral blood cells in human subjects and demonstrated the close relationship of visceral fat adiposity and disturbance of circadian rhythm in peripheral blood cells. In a series of studies, we herein investigated the association of visceral fat adiposity and mRNA levels relating to inflammatory genes in peripheral blood cells. APPROACH AND RESULTS Microarray analysis was performed in peripheral blood cells from 28 obese subjects. Reverse transcription-polymerase chain reaction (RT-PCR) was conducted by using blood cells from 57 obese subjects. Obesity was defined as body mass index (BMI) greater than 25 kg/m2 according to the Japanese criteria. Gene expression profile analysis was carried out with Agilent whole human genome 4×44K oligo-DNA microarray. Gene ontology (GO) analysis showed that 14 genes were significantly associated with visceral fat adiposity among 239 genes relating to inflammation. Among 14 genes, RT-PCR demonstrated that S100A8, S100A9, and S100A12 positively correlated with visceral fat adiposity in 57 subjects. Stepwise multiple regression analysis showed that S100A8 and S100A12 mRNA levels were closely associated with HOMA-IR and S100A9 mRNA was significantly related to adiponectin and CRP. CONCLUSIONS Peripheral blood mRNA levels of S100 family were closely associated with insulin resistance and inflammation.

Ultrastructural Localization of Adiponectin protein in Vasculature of Normal and Atherosclerotic mice

Adiponectin, adipose-specific secretory protein, abundantly circulates in bloodstream and its concentration is around 1000-fold higher than that of other cytokines and hormones. Hypoadiponectinemia is a risk factor for atherosclerosis. There is little or no information on ultrastructural localization of adiponectin in the vasculature. Herein we investigated the localization of vascular adiponectin in the aorta using the immunoelectron microscopic technique. In wild-type (WT) mice, adiponectin was mainly detected on the luminal surface membrane of endothelial cells (ECs) and also found intracellularly in the endocytic vesicles of ECs. In the atherosclerotic lesions of apolipoprotein E-knockout (ApoE-KO) mice, adiponectin was detected in ECs, on the cell surface membrane of synthetic smooth muscle cells, and on the surface of monocytes adherent to ECs. Changes in adiponectin localization within the wall of the aorta may provide novel insight into the pathogenesis of atherosclerosis.

Adiponectin association with T-cadherin protects against neointima proliferation and atherosclerosis

Adiponectin, an adipocyte‐derived protein abundant in the circulation, is thought to be protective against atherosclerosis. However, it is not fully understood how the association of adiponectin with vascular cells and its antiatherogenic effect are connected. In this study, T‐cadherin was essential for accumulation of adiponectin in the neointima and atherosclerotic plaque lesions, and the adiponectin–T‐cadherin association protected against vascular injury. In the apolipoprotein E‐knockout (ApoE‐KO) mice, adiponectin and T‐cadherin colocalized on en‐dothelial cells and synthetic smooth muscle cells in the aortic intima. Notably, aortic adiponectin protein disappeared in T‐cadherin/ApoE double‐knockout (Tcad/ApoE‐DKO) mice with significant elevation of blood adiponectin concentration. Furthermore, in Tcad/ApoE‐DKO mice, carotid artery ligation resulted in a significant increase of neointimal thickness compared with ApoE‐KO mice. Finally, on a high‐cholesterol diet, Tcad/ApoE‐DKO mice increased atherosclerotic plaque formation, despite a 5‐fold increase in plasma adiponectin level compared with that in ApoE‐KO mice. In vitro, knockdown of T‐cadherin from human aortic smooth muscle cells (HASMCs) with synthetic phenotype significantly reduced adiponectin accumulation on HASMCs and negated the inhibitory effect of adiponectin on proinflammatory change. Collective evidence showed that adiponectin accumulates in the vasculature via T‐cadherin, and the adiponectin–T‐cadherin association plays a protective role against neointimal and atheroscle‐rotic plaque formations. —Fujishima, Y., Maeda, N., Matsuda, K., Masuda, S., Mori, T., Fukuda, S., Sekimoto, R., Yamaoka, M., Obata, Y., Kita, S., Nishizawa, H., Funahashi, T., Ranscht, B., Shimomura, I. Adiponectin association with T‐cadherin protects against neointima proliferation and atherosclerosis. FASEB J. 31, 1571–1583 (2017) www.fasebj.org

Systemic arteriosclerosis and eating behavior in Japanese type 2 diabetic patients with visceral fat accumulation.

BackgroundVisceral fat accumulation is a major etiological factor in the progression of type 2 diabetes mellitus and atherosclerosis. We described previously visceral fat accumulation and multiple cardiovascular risk factors in a considerable number of Japanese non-obese subjects (BMI <25 kg/m2). Here, we investigated differences in systemic arteriosclerosis, serum adiponectin concentration, and eating behavior in type 2 diabetic patients with and without visceral fat accumulation.MethodsThe study subjects were 75 Japanese type 2 diabetes mellitus (age: 64.8 ± 11.5 years, mean ± SD). Visceral fat accumulation represented an estimated visceral fat area of 100 cm2 using the bioelectrical impedance analysis method. Subjects were divided into two groups; with (n = 53) and without (n = 22) visceral fat accumulation. Systemic arteriosclerosis was scored for four arteries by ultrasonography. Eating behavior was assessed based on The Guideline for Obesity questionnaire issued by the Japan Society for the Study of Obesity.ResultsThe visceral fat accumulation (+) group showed significantly higher systemic vascular scores and significantly lower serum adiponectin levels than the visceral fat accumulation (−) group. With respect to the eating behavior questionnaire items, (+) patients showed higher values for the total score and many of the major sub-scores than (−) patients.ConclusionsType 2 diabetic patients with visceral fat accumulation showed 1) progression of systemic arteriosclerosis, 2) low serum adiponectin levels, and 3) differences in eating behavior, compared to those without visceral fat accumulation. Taken together, the findings highlight the importance of evaluating visceral fat area in type 2 diabetic patients. Furthermore, those with visceral fat accumulation might need to undergo more intensive screening for systemic arteriosclerosis and consider modifying their eating behaviors.

The unique prodomain of T-cadherin plays a key role in adiponectin binding with the essential extracellular cadherin repeats 1 and 2

Adiponectin, an adipocyte-derived circulating protein, accumulates in the heart, vascular endothelium, and skeletal muscles through an interaction with T-cadherin (T-cad), a unique glycosylphosphatidylinositol-anchored cadherin. Recent studies have suggested that this interaction is essential for adiponectin-mediated cardiovascular protection. However, the precise protein-protein interaction between adiponectin and T-cad remains poorly characterized. Using ELISA-based and surface plasmon analyses, we report here that T-cad fused with IgG Fc as a fusion tag by replacing its glycosylphosphatidylinositol-anchor specifically bound both hexameric and larger multimeric adiponectin with a dissociation constant of ∼1.0 nm and without any contribution from other cellular or serum factors. The extracellular T-cad repeats 1 and 2 were critical for the observed adiponectin binding, which is required for classical cadherin-mediated cell-to-cell adhesion. Moreover, the 130-kDa prodomain-bearing T-cad, uniquely expressed on the cell surface among members of the cadherin family and predominantly increased by adiponectin, contributed significantly to adiponectin binding. Inhibition of prodomain-processing by a prohormone convertase inhibitor increased 130-kDa T-cad levels and also enhanced adiponectin binding to endothelial cells both by more preferential cell-surface localization and by higher adiponectin-binding affinity of 130-kDa T-cad relative to 100-kDa T-cad. The preferential cell-surface localization of 130-kDa T-cad relative to 100-kDa T-cad was also observed in normal mice aorta in vivo. In conclusion, our study shows that a unique key feature of the T-cad prodomain is its involvement in binding of the T-cad repeats 1 and 2 to adiponectin and also demonstrates that adiponectin positively regulates T-cad abundance.

Effect of adiponectin on cardiac β-catenin signaling pathway under angiotensin II infusion.

Obesity is associated with heart failure and cardiac hypertrophy. Adiponectin has been shown to play a protective role for cardiovascular diseases. The β-catenin signaling pathway is deeply involved in cardiac hypertrophy. However, the effect of adiponectin on β-catenin signaling has not been investigated in cardiac hypertrophy. Present study aimed to clarify the involvement of adiponectin and β-catenin signaling pathway in the mouse model of angiotensin II (AngII)-induced cardiac hypertrophy. In hearts of Wild type (WT) mice, AngII dose-dependently augmented cytosolic β-catenin protein level. WT and adiponectin knockout (Adipo-KO) mice were administered with AngII at 2.4 mg/kg/day for 14 days and were also injected with adenovirus expressing the adiponectin (Ad-Adipo) or the β-galactosidase (Ad-βgal). Cardiac mRNA levels relating to hypertrophy and β-catenin signaling were increased in Adipo-KO mice and these changes were reversed by Ad-Adipo. Phosphorylation of Akt was increased in Adipo-KO mice and such increases were reversed by Ad-Adipo. Furthermore, the phosphorylation of glycogen synthase kinase 3β (GSK3β) at Ser(9) and cytosolic β-catenin level were increased in Adipo-KO mice and they were significantly reduced by Ad-Adipo treatment. Phosphorylation of mammalian target of rapamycin (mTOR) was reduced by Ad-Adipo-mediated adiponectin supplementation in WT and Adipo-KO mice. The current study suggests that adiponectin attenuates AngII-induced cardiac hypertrophic signals partly through Akt/GSK3β/β-catenin and Akt/mTOR pathways.

Adiponectin/T-cadherin system enhances exosome biogenesis and decreases cellular ceramides by exosomal release

Adiponectin, an adipocyte-derived circulating protein, accumulates in vasculature, heart, and skeletal muscles through interaction with a unique glycosylphosphatidylinositol-anchored cadherin, T-cadherin. Recent studies have demonstrated that such accumulation is essential for adiponectin-mediated cardiovascular protection. Here, we demonstrate that the adiponectin/T-cadherin system enhances exosome biogenesis and secretion, leading to the decrease of cellular ceramides. Adiponectin accumulated inside multivesicular bodies, the site of exosome generation, in cultured cells and in vivo aorta, and also in exosomes in conditioned media and in blood, together with T-cadherin. The systemic level of exosomes in blood was significantly affected by adiponectin or T-cadherin in vivo. Adiponectin increased exosome biogenesis from the cells, dependently on T-cadherin, but not on AdipoR1 or AdipoR2. Such enhancement of exosome release accompanied the reduction of cellular ceramides through ceramide efflux in exosomes. Consistently, the ceramide reduction by adiponectin was found in aortas of WT mice treated with angiotensin II, but not in T-cadherin-knockout mice. Our findings provide insights into adiponectin/T-cadherin-mediated organ protection through exosome biogenesis and secretion.