Diet-induced obesity in zebrafish shares common pathophysiological pathways with mammalian obesity

<p>Abstract</p> <p>Background</p> <p>Obesity is a multifactorial disorder influenced by genetic and environmental factors. Animal models of obesity are required to help us understand the signaling pathways underlying this condition. Zebrafish possess many structural and functional similarities with humans and have been used to model various human diseases, including a genetic model of obesity. The purpose of this study was to establish a zebrafish model of diet-induced obesity (DIO).</p> <p>Results</p> <p>Zebrafish were assigned into two dietary groups. One group of zebrafish was overfed with <it>Artemia </it>(60 mg dry weight/day/fish), a living prey consisting of a relatively high amount of fat. The other group of zebrafish was fed with <it>Artemia </it>sufficient to meet their energy requirements (5 mg dry weight/day/fish). Zebrafish were fed under these dietary protocols for 8 weeks. The zebrafish overfed with <it>Artemia </it>exhibited increased body mass index, which was calculated by dividing the body weight by the square of the body length, hypertriglyceridemia and hepatosteatosis, unlike the control zebrafish. Calorie restriction for 2 weeks was applied to zebrafish after the 8-week overfeeding period. The increased body weight and plasma triglyceride level were improved by calorie restriction. We also performed comparative transcriptome analysis of visceral adipose tissue from DIO zebrafish, DIO rats, DIO mice and obese humans. This analysis revealed that obese zebrafish and mammals share common pathophysiological pathways related to the coagulation cascade and lipid metabolism. Furthermore, several regulators were identified in zebrafish and mammals, including APOH, IL-6 and IL-1β in the coagulation cascade, and SREBF1, PPARα/γ, NR1H3 and LEP in lipid metabolism.</p> <p>Conclusion</p> <p>We established a zebrafish model of DIO that shared common pathophysiological pathways with mammalian obesity. The DIO zebrafish can be used to identify putative pharmacological targets and to test novel drugs for the treatment of human obesity.</p

In vivo imaging of zebrafish retinal cells using fluorescent coumarin derivatives

<p>Abstract</p> <p>Background</p> <p>The zebrafish visual system is a good research model because the zebrafish retina is very similar to that of humans in terms of the morphologies and functions. Studies of the retina have been facilitated by improvements in imaging techniques. <it>In vitro </it>techniques such as immunohistochemistry and <it>in vivo </it>imaging using transgenic zebrafish have been proven useful for visualizing specific subtypes of retinal cells. In contrast, <it>in vivo </it>imaging using organic fluorescent molecules such as fluorescent sphingolipids allows non-invasive staining and visualization of retinal cells <it>en masse</it>. However, these fluorescent molecules also localize to the interstitial fluid and stain whole larvae.</p> <p>Results</p> <p>We screened fluorescent coumarin derivatives that might preferentially stain neuronal cells including retinal cells. We identified four coumarin derivatives that could be used for <it>in vivo </it>imaging of zebrafish retinal cells. The retinas of living zebrafish could be stained by simply immersing larvae in water containing 1 μg/ml of a coumarin derivative for 30 min. By using confocal laser scanning microscopy, the lamination of the zebrafish retina was clearly visualized. Using these coumarin derivatives, we were able to assess the development of the zebrafish retina and the morphological abnormalities induced by genetic or chemical interventions. The coumarin derivatives were also suitable for counter-staining of transgenic zebrafish expressing fluorescent proteins in specific subtypes of retinal cells.</p> <p>Conclusions</p> <p>The coumarin derivatives identified in this study can stain zebrafish retinal cells in a relatively short time and at low concentrations, making them suitable for <it>in vivo </it>imaging of the zebrafish retina. Therefore, they will be useful tools in genetic and chemical screenings using zebrafish to identify genes and chemicals that may have crucial functions in the retina.</p

Rationale and design of a multicenter randomized study for evaluating vascular function under uric acid control using the xanthine oxidase inhibitor, febuxostat : the PRIZE study

Background: Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces endothelial dysfunction and inflammatory reactions in vascular systems, leading to atherosclerosis. Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. We designed the PRIZE study to evaluate the effects of febuxostat on a surrogate marker of cardiovascular disease risk, ultrasonography-based intima-media thickness of the carotid artery in patients with hyperuricemia. Methods: The study is a multicenter, prospective, randomized, open-label and blinded-endpoint evaluation (PROBE) design. A total of 500 patients with asymptomatic hyperuricemia (uric acid >7.0 mg/dL) and carotid intima-media thickness ≥1.1 mm will be randomized centrally to receive either febuxostat (10–60 mg/day) or non-pharmacological treatment. Randomization is carried out using the dynamic allocation method stratified according to age (<65, ≥65 year), gender, presence or absence of diabetes mellitus, serum uric acid (<8.0, ≥8.0 mg/dL), and carotid intima-media thickness (<1.3, ≥1.3 mm). In addition to administering the study drug, we will also direct lifestyle modification in all participants, including advice on control of body weight, sleep, exercise and healthy diet. Carotid intima-media thickness will be evaluated using ultrasonography performed by skilled technicians at a central laboratory. Follow-up will be continued for 24 months. The primary endpoint is percentage change in mean intima-media thickness of the common carotid artery 24 months after baseline, measured by carotid ultrasound imaging. Conclusions: PRIZE will be the first study to provide important data on the effects of febuxostat on atherosclerosis in patients with asymptomatic hyperuricemia

Zinc finger MYND-type containing 8 promotes tumour angiogenesis via induction of vascular endothelial growth factor-A expression

application/pdf内容の要旨・審査結果の要旨 / 三重大学大学院医学系研究科 生命医科学専攻ゲノム再生医学講座 薬理ゲノミクス教育研究分

Zinc finger MYND-type containing 8 promotes tumour angiogenesis via induction of vascular endothelial growth factor-A expression

application/pdfZinc finger, MYND-type containing 8 (ZMYND8) encodes a receptor for activated C-kinase protein. Here, we report that ZMYND8 promotes angiogenesis in prostate cancer xenografts in zebrafish, as well as tube formation in human umbilical vascular endothelial cell (HUVEC) cultures. Using transcriptome analyses, we found upregulation of ZMYND8 expression in both zebrafish prostate cancer xenografts and prostate cancer samples from patients. In vitro and in vivo ZMYND8 knockdown suppressed angiogenesis, whereas ZMYND8 overexpression enhanced angiogenesis. Notably, ZMYND8 induced vegfa mRNA expression selectively in prostate cancer xenografts. Integrated analysis of human and zebrafish transcriptomes, which identified ZMYND8, might be a powerful strategy to determine also other molecular targets for inhibiting prostate cancer progression.本文 / Department of Molecular and Cellular Pharmacology, Pharmacogenomics and Pharmacoinformatics, Mie University Graduate School of Medicine8

Green tea extract suppresses adiposity and affects the expression of lipid metabolism genes in diet-induced obese zebrafish

<p>Abstract</p> <p>Background</p> <p>Visceral fat accumulation is one of the most important predictors of mortality in obese populations. Administration of green tea extract (GTE) can reduce body fat and reduce the risk of obesity-related diseases in mammals. In this study, we investigated the effects and mechanisms of GTE on adiposity in diet-induced obese (DIO) zebrafish.</p> <p>Methods</p> <p>Zebrafish at 3.5 to 4.5 months post-fertilization were allocated to four groups: non-DIO, DIO, DIO + 0.0025%GTE, and DIO + 0.0050%GTE. The non-DIO group was fed freshly hatched <it>Artemia</it> once daily (5 mg cysts/fish daily) for 40 days. Zebrafish in the three DIO groups were fed freshly hatched <it>Artemia</it> three times daily (60 mg cysts/fish daily). Zebrafish in the DIO + 0.0025%GTE and DIO + 0.0050%GTE groups were exposed to GTE after the start of feeding three times daily for 40 days.</p> <p>Results</p> <p>Three-dimensional microcomputed tomography analysis showed that GTE exposure significantly decreased the volume of visceral but not subcutaneous fat tissue in DIO zebrafish. GTE exposure increased hepatic expression of the lipid catabolism genes <it>ACOX1</it> (<it>acyl-coenzyme A oxidase 1, palmitoyl</it>), <it>ACADM</it> (<it>acyl-coenzyme A dehydrogenase, c-4 to c-12 straight chain)</it>, and <it>PPARA</it> (<it>peroxisome proliferator-activated receptor alpha</it>). GTE exposure also significantly decreased the visceral fat expression of <it>SOCS3</it> (<it>suppressor of cytokine signaling 3b</it>) which inhibits leptin signaling.</p> <p>Conclusions</p> <p>The present results are consistent with those seen in mammals treated with GTE, supporting the validity of studying the effects of GTE in DIO zebrafish. Our results suggest that GTE exerts beneficial effects on adiposity, possibly by altering the expression of lipid catabolism genes and <it>SOCS3</it>.</p