| 1. |
- Carobbio, Stefania, et al.
(författare)
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Adaptive changes of the Insig1/SREBP1/SCD1 set point help adipose tissue to cope with increased storage demands of obesity
- 2013
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Ingår i: Diabetes. - : Cell Press. - 0012-1797 .- 1939-327X. ; 62:11, s. 3697-3708
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Tidskriftsartikel (refereegranskat)abstract
- The epidemic of obesity imposes unprecedented challenges on human adipose tissue (WAT) storage capacity that may benefit from adaptive mechanisms to maintain adipocyte functionality. Here, we demonstrate that changes in the regulatory feedback set point control of Insig1/SREBP1 represent an adaptive response that preserves WAT lipid homeostasis in obese and insulin-resistant states. In our experiments, we show that Insig1 mRNA expression decreases in WAT from mice with obesity-associated insulin resistance and from morbidly obese humans and in in vitro models of adipocyte insulin resistance. Insig1 downregulation is part of an adaptive response that promotes the maintenance of SREBP1 maturation and facilitates lipogenesis and availability of appropriate levels of fatty acid unsaturation, partially compensating the antilipogenic effect associated with insulin resistance. We describe for the first time the existence of this adaptive mechanism in WAT, which involves Insig1/SREBP1 and preserves the degree of lipid unsaturation under conditions of obesity-induced insulin resistance. These adaptive mechanisms contribute to maintain lipid desaturation through preferential SCD1 regulation and facilitate fat storage in WAT, despite on-going metabolic stress.
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| 2. |
- Blösch, Günter, et al.
(författare)
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Twenty-three unsolved problems in hydrology (UPH) - a community perspective
- 2019
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Ingår i: Hydrological Sciences Journal. - : Informa UK Limited. - 0262-6667 .- 2150-3435. ; 64:10, s. 1141-1158
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Tidskriftsartikel (refereegranskat)abstract
- This paper is the outcome of a community initiative to identify major unsolved scientific problems in hydrology motivated by a need for stronger harmonisation of research efforts. The procedure involved a public consultation through online media, followed by two workshops through which a large number of potential science questions were collated, prioritised, and synthesised. In spite of the diversity of the participants (230 scientists in total), the process revealed much about community priorities and the state of our science: a preference for continuity in research questions rather than radical departures or redirections from past and current work. Questions remain focused on the process-based understanding of hydrological variability and causality at all space and time scales. Increased attention to environmental change drives a new emphasis on understanding how change propagates across interfaces within the hydrological system and across disciplinary boundaries. In particular, the expansion of the human footprint raises a new set of questions related to human interactions with nature and water cycle feedbacks in the context of complex water management problems. We hope that this reflection and synthesis of the 23 unsolved problems in hydrology will help guide research efforts for some years to come.
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| 3. |
- Bravard, Amélie, et al.
(författare)
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Metformin treatment for 8 days impacts multiple intestinal parameters in high-fat high-sucrose fed mice
- 2021
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Although the mechanism of action of the antidiabetic drug metformin is still a matter of discussions, it is well accepted that the gut plays an important role. To gain more insights into the mechanisms occurring in the different regions of the intestine, adult male mice were fed a high-fat-high sucrose (HFS) diet for 8 days and treated with metformin by gavage (300 mg/day/kg body weight) during the HFS diet. Metformin counteracted HFS diet-induced overexpression of a network of genes involved in the transport of glucose and fatty acids in the different regions of the small intestine. It also induced beneficial modification of secondary bile acid profile in the caecum, with a reduction of deoxycholic acid and lithocholic acid levels and increased abundance of ursodeoxycholic acid and tauroursodeoxycholic acid, potentially leading to FRX inhibition. In parallel, metformin treatment was associated with specific changes of the microbiota composition in the lumen of the different regions of the intestine. Metformin induced a marked increase in the abundance of Akkermansia muciniphila in the lumen all along the gut and counteracted the effects of HFS diet on the abundances of some bacterial groups generally associated with metabolic disturbances (f-Lachnospiraceae, f-Petostreptococcaceae, g-Clostidium). Therefore, the present work clearly emphasises the role of all the regions of the intestinal tract in the beneficial action of the antidiabetic drug metformin in a prediabetic mouse model.
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| 4. |
- Holst, Mikkel Roland, et al.
(författare)
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Clathrin-Independent Endocytosis Suppresses Cancer Cell Blebbing and Invasion
- 2017
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Ingår i: Cell Reports. - : Cell Press. - 2211-1247. ; 20:8, s. 1893-1905
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Tidskriftsartikel (refereegranskat)abstract
- Cellular blebbing, caused by local alterations in cellsurface tension, has been shown to increase the invasiveness of cancer cells. However, the regulatory mechanisms balancing cell-surface dynamics and bleb formation remain elusive. Here, we show that an acute reduction in cell volume activates clathrinindependent endocytosis. Hence, a decrease in surface tension is buffered by the internalization of the plasma membrane (PM) lipid bilayer. Membrane invagination and endocytosis are driven by the tension- mediated recruitment of the membrane sculpting and GTPase-activating protein GRAF1 (GTPase regulator associated with focal adhesion kinase-1) to the PM. Disruption of this regulation by depleting cells of GRAF1 or mutating key phosphatidylinositol- interacting amino acids in the protein results in increased cellular blebbing and promotes the 3D motility of cancer cells. Our data support a role for clathrin-independent endocytic machinery in balancing membrane tension, which clarifies the previously reported role of GRAF1 as a tumor suppressor.
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| 5. |
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| 6. |
- Jiao, Hong, et al.
(författare)
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Genetic Association and Gene Expression Analysis Identify FGFR1 as a New Susceptibility Gene for Human Obesity
- 2011
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 96:6, s. E962-E966
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Tidskriftsartikel (refereegranskat)abstract
- Context: Previous studies suggest a role for fibroblast growth factor receptor 1 (FGFR1) in the regulation of energy balance. Objective: Our objective was to investigate whether FGFR1 is an obesity gene by genetic association and functional studies. Design: The study was designed to genotype common FGFR1 single-nucleotide polymorphisms (SNP) in large cohorts, confirm significant results in additional cohorts, and measure FGFR1 expression in human adipose tissue and in rodent hypothalamus. Setting: General community and referral centers for specialized care was the setting for the study. Participants: We genotyped FGFR1 SNP in 2438 obese and 2115 lean adults and 985 obese and 532 population-based children. Results were confirmed in 928 obese and 2738 population-based adults and 487 obese and 441 lean children. Abdominal sc adipose tissue was investigated in 202 subjects. We also investigated diet-induced, obese fasting, and fed rats. Main Outcome Measures: We analyzed the association between FGFR1 SNP and obesity. In secondary analyses, we related adipose FGFR1 expression to genotype, obesity, and degree of fat cell differentiation and related hypothalamic FGFR1 to energy balance. Results: FGFR1 rs7012413*T was nominally associated with obesity in all four cohorts; metaanalysis odds ratio = 1.17 (95% confidence interval = 1.10-1.25), and P = 1.8 x 10(-6), which was P = 7.0 x 10(-8) in the recessive model. rs7012413*T was associated with FGFR1 expression in adipose tissue (P < 0.0001). In this organ, but not in skeletal muscle, FGFR1 mRNA (P < 0.0001) and protein (P < 0.05) were increased in obesity. In rats, hypothalamic expression of FGFR1 declined after fasting (P < ]0.001) and increased after diet-induced obesity (P < 0.05). Conclusions: FGFR1 is a novel obesity gene that may promote obesity by influencing adipose tissue and the hypothalamic control of appetite.
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