| 1. |
- Karlsson-Lindahl, Linda, 1972, et al.
(author)
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Heparanase affects food intake and regulates energy balance in mice.
- 2012
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In: PloS one. - San Francisco : Public Library of Science (PLoS). - 1932-6203. ; 7:3
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Journal article (peer-reviewed)abstract
- Mutation of the melanocortin-receptor 4 (MC4R) is the most frequent cause of severe obesity in humans. Binding of agouti-related peptide (AgRP) to MC4R involves the co-receptor syndecan-3, a heparan sulfate proteoglycan. The proteoglycan can be structurally modified by the enzyme heparanase. Here we tested the hypothesis that heparanase plays a role in food intake behaviour and energy balance regulation by analysing body weight, body composition and food intake in genetically modified mice that either lack or overexpress heparanase. We also assessed food intake and body weight following acute central intracerebroventricular administration of heparanase; such treatment reduced food intake in wildtype mice, an effect that was abolished in mice lacking MC4R. By contrast, heparanase knockout mice on a high-fat diet showed increased food intake and maturity-onset obesity, with up to a 40% increase in body fat. Mice overexpressing heparanase displayed essentially the opposite phenotypes, with a reduced fat mass. These results implicate heparanase in energy balance control via the central melanocortin system. Our data indicate that heparanase acts as a negative modulator of AgRP signaling at MC4R, through cleavage of heparan sulfate chains presumably linked to syndecan-3.
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| 2. |
- Benrick, Anna, 1979, et al.
(author)
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Interleukin-6 gene knockout influences energy balance regulating peptides in the hypothalamic paraventricular and supraoptic nuclei.
- 2009
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In: Journal of neuroendocrinology. - : Wiley. - 1365-2826 .- 0953-8194. ; 21:7, s. 620-8
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Journal article (peer-reviewed)abstract
- Interleukin (IL)-6 is a pro-inflammatory cytokine that also affects metabolic function because IL-6 depleted (IL-6(-/-)) mice develop late-onset obesity. IL-6 appears to act in the central nervous system, presumably in the hypothalamus, to increase energy expenditure that appears to involve stimulation of the sympathetic nervous system. In the present study, we explored possible central mechanisms for the effects exerted by IL-6 on body fat. Therefore, we measured the effects of IL-6 depletion in IL-6(-/-) mice on expression of key hypothalamic peptide genes involved in energy balance by the real time polymerase chain reaction. Additionally, co-localisation between such peptides and IL-6 receptor alpha was investigated by immunohistochemistry. IL-6 deficiency decreased the expression of several peptides found in the paraventricular nucleus (PVN), which is a nucleus that has been attributed an adipostatic function. For example, corticotrophin-releasing hormone (CRH), which is reported to stimulate the sympathetic nervous system, was decreased by 40% in older IL-6(-/-) mice. Oxytocin, which is reported to prevent obesity, was also decreased in older IL-6(-/-) animals, as was arginine vasopressin (AVP). The IL-6 receptor alpha was abundantly expressed in the PVN, but also in the supraoptic nucleus, and was shown to be co-expressed to a high extent with CRH, AVP, oxytocin and thyrotrophin-releasing hormone. These data indicate that depletion of endogenous IL-6, a body fat suppressing cytokine, is associated with the decreased expression of CRH and oxytocin (i.e. energy balance regulating peptides) as well as AVP in the PVN. Because IL-6 receptor alpha is co-expressed with CRH, oxytocin and AVP, IL-6 could stimulate the expression of these peptides directly.
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| 3. |
- Carlsson, Lena M S, 1957, et al.
(author)
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Long-term incidence of serious fall-related injuries after bariatric surgery in Swedish obese subjects.
- 2019
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In: International journal of obesity (2005). - : Springer Science and Business Media LLC. - 1476-5497 .- 0307-0565. ; 43:4, s. 933-937
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Journal article (peer-reviewed)abstract
- Obesity increases risk of falling, but the effect of bariatric surgery on fall-related injuries is unknown. The aim of this study was therefore to study the association between bariatric surgery and long-term incidence of fall-related injuries in the prospective, controlled Swedish Obese Subjects study. At inclusion, body mass index was≥34kg/m2 in men and ≥38kg/m2 in women. The surgery per-protocol group (n=2007) underwent gastric bypass (n=266), banding (n=376), or vertical banded gastroplasty (n=1365), and controls (n=2040) received usual care. At the time of analysis (31 December 2013), median follow-up was 19 years (maximal 26 years). Fall-related injuries requiring hospital treatment were captured using data from the Swedish National Patient Register. During follow-up, there were 617 first-time fall-related injuries in the surgery group and 513 in the control group (adjusted hazard ratio 1.21, 95% CI, 1.07-1.36; P=0.002). The incidence differed between treatment groups (P<0.001, log-rank test) and was higher after gastric bypass than after usual care, banding and vertical banded gastroplasty (adjusted hazard ratio 0.50-0.52, P<0.001 for all three comparisons). In conclusion, gastric bypass surgery was associated with increased risk of serious fall-related injury requiring hospital treatment.
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| 4. |
- Hansson, Caroline, 1981, et al.
(author)
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Influence of ghrelin on the central serotonergic signaling system in mice
- 2014
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In: Neuropharmacology. - : Elsevier BV. - 0028-3908. ; 79, s. 498-505
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Journal article (peer-reviewed)abstract
- The central ghrelin signaling system engages key pathways of importance for feeding control, recently shown to include those engaged in anxiety-like behavior in rodents. Here we sought to determine whether ghrelin impacts on the central serotonin system, which has an important role in anxiety. We focused on two brain areas, the amygdala (of importance for the mediation of fear and anxiety) and the dorsal raphe (i.e. the site of origin of major afferent serotonin pathways, including those that project to the amygdala). In these brain areas, we measured serotonergic turnover (using HPLC) and the mRNA expression of a number of serotonin-related genes (using real-time PCR). We found that acute central administration of ghrelin to mice increased the serotonergic turnover in the amygdala. It also increased the mRNA expression of a number of serotonin receptors, both in the amygdala and in the dorsal raphe. Studies in ghrelin receptor (GHS-R1A) knock-out mice showed a decreased mRNA expression of serotonergic receptors in both the amygdala and the dorsal raphe, relative to their wild-type littermates. We conclude that the central serotonin system is a target for ghrelin, providing a candidate neurochemical substrate of importance for ghrelin's effects on mood. © 2013 The Authors. Published by Elsevier Ltd. All rights reserved.
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| 5. |
- Jörnsten, Rebecka, 1971, et al.
(author)
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Network modeling of the transcriptional effects of copy number aberrations in glioblastoma
- 2011
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In: Molecular Systems Biology. - : EMBO. - 1744-4292. ; 7
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Journal article (peer-reviewed)abstract
- DNA copy number aberrations (CNAs) are a hallmark of cancer genomes. However, little is known about how such changes affect global gene expression. We develop a modeling framework, EPoC (Endogenous Perturbation analysis of Cancer), to (1) detect disease-driving CNAs and their effect on target mRNA expression, and to (2) stratify cancer patients into long- and short-term survivors. Our method constructs causal network models of gene expression by combining genome-wide DNA- and RNA-level data. Prognostic scores are obtained from a singular value decomposition of the networks. By applying EPoC to glioblastoma data from The Cancer Genome Atlas consortium, we demonstrate that the resulting network models contain known disease-relevant hub genes, reveal interesting candidate hubs, and uncover predictors of patient survival. Targeted validations in four glioblastoma cell lines support selected predictions, and implicate the p53-interacting protein Necdin in suppressing glioblastoma cell growth. We conclude that large-scale network modeling of the effects of CNAs on gene expression may provide insights into the biology of human cancer. Free software in MATLAB and R is provided.
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| 6. |
- Kalén, Mattias, et al.
(author)
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Combination of reverse and chemical genetic screens reveals angiogenesis inhibitors and targets.
- 2009
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In: Chemistry & biology. - : Elsevier BV. - 1879-1301 .- 1074-5521. ; 16:4, s. 432-41
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Journal article (peer-reviewed)abstract
- We combined reverse and chemical genetics to identify targets and compounds modulating blood vessel development. Through transcript profiling in mice, we identified 150 potentially druggable microvessel-enriched gene products. Orthologs of 50 of these were knocked down in a reverse genetic screen in zebrafish, demonstrating that 16 were necessary for developmental angiogenesis. In parallel, 1280 pharmacologically active compounds were screened in a human cell-based assay, identifying 28 compounds selectively inhibiting endothelial sprouting. Several links were revealed between the results of the reverse and chemical genetic screens, including the serine/threonine (S/T) phosphatases ppp1ca, ppp1cc, and ppp4c and an inhibitor of this gene family; Endothall. Our results suggest that the combination of reverse and chemical genetic screens, in vertebrates, is an efficient strategy for the identification of drug targets and compounds that modulate complex biological systems, such as angiogenesis.
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| 7. |
- Salomé, Nicolas, et al.
(author)
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On the central mechanism underlying ghrelin's chronic pro-obesity effects in rats: new insights from studies exploiting a potent ghrelin receptor antagonist.
- 2009
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In: Journal of neuroendocrinology. - : Wiley. - 1365-2826 .- 0953-8194. ; 21:9, s. 777-85
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Journal article (peer-reviewed)abstract
- In the present study, we explore the central nervous system mechanism underlying the chronic central effects of ghrelin with respect to increasing body weight and body fat. Specifically, using a recently developed ghrelin receptor antagonist, GHS-R1A (JMV2959), we investigate the role of GHS-R1A in mediating the effects of ghrelin on energy balance and on hypothalamic gene expression. As expected, in adult male rats, chronic central treatment with ghrelin for 14 days, when compared to vehicle-treated control rats, resulted in an increased body weight, lean mass and fat mass (assessed by dual X-ray absorptiometry), dissected white fat pad weight, cumulative food intake, food efficiency, respiratory exchange ratio and a decrease of energy expenditure. Co-administration of the ghrelin receptor antagonist JMV2959 suppressed/blocked the majority of these effects, with the notable exception of ghrelin-induced food intake and food efficiency. The hypothesis emerging from these data, namely that GHS-R1A mediates the chronic effects of ghrelin on fat accumulation, at least partly independent of food intake, is discussed in light of the accompanying data regarding the hypothalamic genes coding for peptides and receptors involved in energy balance regulation, which were found to have altered expression in these studies.
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| 8. |
- Schéle, Erik, 1980, et al.
(author)
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Interleukin-6 Receptor alpha is Co-localised with Melanin-Concentrating Hormone in Human and Mouse Hypothalamus
- 2012
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In: Journal of Neuroendocrinology. - : Wiley. - 0953-8194. ; 24:6, s. 930-943
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Journal article (peer-reviewed)abstract
- Interleukin (IL)-6 deficient mice develop mature-onset obesity. Furthermore, i.c.v. administration of IL-6 increases energy expenditure, suggesting that IL-6 centrally regulates energy homeostasis. To investigate whether it would be possible for IL-6 to directly influence the energy homeostasis via hypothalamic regulation in humans and rodents, we mapped the distribution of the ligand binding IL-6 receptor a (IL-6Ra) in this brain region. In the human hypothalamus, IL-6Ra-immunoreactivity was detected in perikarya and first-order dendrites of neurones. The IL-6Ra-immunoreactive (-IR) neurones were observed posterior to the level of the interventricular foramen. There, IL-6Ra-IR neurones were located in the lateral hypothalamic, perifornical, dorsal and posterior hypothalamic areas, the hypothalamic dorsomedial nucleus and in the zona incerta. In the caudal part of the hypothalamus, the density of the IL-6Ra-IR neurones gradually increased. Double-labelling immunofluorescent studies demonstrated that IL-6Ra immunoreactivity was localised in the same neurones as the orexigenic neuropeptide, melanin-concentrating hormone (MCH). By contrast, IL-6Ra-immunoreactivity was not observed in the orexin B-IR neurones. To determine whether the observed expression of IL-6Ra is evolutionary conserved, we studied the co-localisation of IL-6Ra with MCH and orexin in the mouse hypothalamus, where IL-6Ra-immunoreactivity was present in numerous MCH-IR and orexin-IR neurones. Our data demonstrate that the MCH neurones of the human hypothalamus, as well as the MCH and orexin neurones of the mouse hypothalamus, contain IL-6Ra. This opens up the possibility that IL-6 influences the energy balance through the MCH neurones in humans, and both MCH and orexin neurones in mice.
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| 9. |
- Shao, Linus Ruijin, 1964, et al.
(author)
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Clomiphene citrate causes aberrant tubal apoptosis and estrogen receptor activation in rat fallopian tube: implications for tubal ectopic pregnancy.
- 2009
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In: Biology of reproduction. - : Oxford University Press (OUP). - 0006-3363 .- 1529-7268. ; 80:6, s. 1262-71
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Journal article (peer-reviewed)abstract
- Clomiphene citrate (CC) therapy for disorders of anovulatory infertility has been linked to an increased frequency of tubal ectopic pregnancy. Although CC enhances apoptotic processes in the ovaries, villi, and decidual tissues, its effect on apoptosis in the fallopian tube is unknown. Here, we show that chronic treatment with CC induces tubal apoptosis, but not necrosis, through an intrinsic mitochondria-dependent signaling pathway in vivo. The apoptosis was specific to epithelial cells in the isthmus, and the damage was reversed with 17beta-estradiol (E2); however, pretreatment or concomitant treatment with E2 did not protect against tubal apoptosis induced by chronic treatment with CC. Chronic treatment activated estrogen receptors (ESRs), particularly cilia-localized ESR2A (formerly ERbeta2). In contrast to E2, acute treatment of superovulating rats with a high dose of CC or the ESR2-selective agonist 2,3-bis (4-hydroxyphenyl)-propionitrile (DPN) significantly delayed the transport of oocyte-cumulus complexes through the fallopian tube. Our findings suggest that in response to chronic CC therapy, isthmus-specific apoptosis of epithelial cells and activation of cilia-ESR2A act in parallel to block gamete and embryo passage through the fallopian tube, eventually resulting in tubal ectopic pregnancy.
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| 10. |
- Shao, Linus Ruijin, 1964, et al.
(author)
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Down-Regulation of Cilia-Localized IL-6R{alpha} by 17{beta}-Estradiol in Mouse and Human Fallopian Tubes.
- 2009
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In: American journal of physiology. Cell physiology. - : American Physiological Society. - 0363-6143 .- 1522-1563. ; 297:1
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Journal article (peer-reviewed)abstract
- The action of Interleukin-6 (IL-6) impacts female reproduction. Although IL-6 was recently shown to inhibit cilia activity in human fallopian tubes in vitro, the molecular mechanisms underlying IL-6 signaling to tubal function remain elusive. Here, we investigate the cellular localization, regulation, and possible function of two IL-6 receptors (IL-6Ralpha and gp130) in mouse and human fallopian tubes in vivo. We show that IL-6Ralpha is restricted to the cilia of epithelial cells in both mouse and human fallopian tubes. Exogenous 17beta-estradiol (E2), but not progesterone (P4), causes a time-dependent decrease in IL-6Ralpha expression which is blocked by the estrogen receptor (ER) antagonist ICI 182,780. Exposure of different ER-selective agonists, PTT or DPN, demonstrated an ER subtype-specific regulation of IL-6Ralphaalpha in mouse fallopian tubes. In contrast to IL-6Ralpha, gp130 was detected in tubal epithelial cells in mice but not in humans. In humans, gp130 was found in the muscle cells and was decreased in the periovulatory and luteal phases during the reproductive cycles, indicating a species-specific expression and regulation of gp130 in the fallopian tube. Expression of tubal IL-6Ralpha and gp130 in IL-6 knockout mice was found to be normal; however, E2 treatment increased IL-6Ralpha, but not gp130, in IL-6 knockout mice compared to wild-type mice. Furthermore, expression levels of IL-6Ralpha, but not gp130, decreased in parallel with estrogenic accelerated oocyte-cumulus complex (OCC) transport in mouse fallopian tubes. Our findings unveil a potential role for cilia-specific IL-6Ralpha in the regulation of OCC transport and suggest an estrogen-regulatory pathway of IL-6Ralpha in the fallopian tube. Key words: estrogen, IL-6R, cilia, fallopian tube.
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