PON2 Deficiency Leads to Increased Susceptibility to Diet-Induced Obesity.

(1) Background: Paraoxonase 2 (PON2) is a ubiquitously expressed protein localized to endoplasmic reticulum and mitochondria. Previous studies have shown that PON2 exhibits anti-oxidant and anti-inflammatory functions, and PON2-deficient (PON2-def) mice are more susceptible to atherosclerosis. Furthermore, PON2 deficiency leads to impaired mitochondrial function. (2) Methods: In this study, we examined the susceptibility of PON2-def mice to diet-induced obesity. (3) Results: After feeding of an obesifying diet, the PON2-def mice exhibited significantly increased body weight due to increased fat mass weight as compared to the wild-type (WT) mice. The increased adiposity was due, in part, to increased adipocyte hypertrophy. PON2-def mice had increased fasting insulin levels and impaired glucose tolerance after diet-induced obesity. PON2-def mice had decreased oxygen consumption and energy expenditure. Furthermore, the oxygen consumption rate of subcutaneous fat pads from PON2-def mice was lower compared to WT mice. Gene expression analysis of the subcutaneous fat pads revealed decreased expression levels of markers for beige adipocytes in PON2-def mice. (4) Conclusions: We concluded that altered systemic energy balance, perhaps due to decreased beige adipocytes and mitochondrial dysfunction in white adipose tissue of PON2-def mice, leads to increased obesity in these mice

Metabolic profiling of follistatin overexpression: a novel therapeutic strategy for metabolic diseases.

Background: Follistatin (Fst) promotes brown adipocyte characteristics in adipose tissues. Methods: Abdominal fat volume (CT scan), glucose clearance (GTT test), and metabolomics analysis (mass spectrometry) of adipose tissues from Fst transgenic (Fst-Tg) and wild type (WT) control mice were analyzed. Oxygen consumption (Seahorse Analyzer) and lipidomics (gas chromatography) was analyzed in 3T3-L1 cells. Results: Fst-Tg mice show significant decrease in abdominal fat content, increased glucose clearance, improved plasma lipid profiles and significant changes in several conventional metabolites compared to the WT mice. Furthermore, overexpression of Fst in 3T3-L1 cells resulted in up regulation of key brown/beige markers and changes in lipidomics profiles. Conclusion: Fst modulates key factors involved in promoting metabolic syndrome and could be used for therapeutic intervention. Diabetes Metab Syndr Obes 2018 Mar 26; 11:65-84

Noggin depletion in adipocytes promotes obesity in mice.

ObjectiveObesity has increased to pandemic levels and enhanced understanding of adipose regulation is required for new treatment strategies. Although bone morphogenetic proteins (BMPs) influence adipogenesis, the effect of BMP antagonists such as Noggin is largely unknown. The aim of the study was to define the role of Noggin, an extracellular BMP inhibitor, in adipogenesis.MethodsWe generated adipose-derived progenitor cells and a mouse model with adipocyte-specific Noggin deletion using the AdiponectinCre transgenic mouse, and determined the adipose phenotype of Noggin-deficiency.ResultsOur studies showed that Noggin is expressed in progenitor cells but declines in adipocytes, possibly allowing for lipid accumulation. Correspondingly, adipocyte-specific Noggin deletion in vivo promoted age-related obesity in both genders with no change in food intake. Although the loss of Noggin caused white adipose tissue hypertrophy, and whitening and impaired function in brown adipose tissue in both genders, there were clear gender differences with the females being most affected. The females had suppressed expression of brown adipose markers and thermogenic genes including peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC1alpha) and uncoupling protein 1 (UCP1) as well as genes associated with adipogenesis and lipid metabolism. The males, on the other hand, had early changes in a few BAT markers and thermogenic genes, but the main changes were in the genes associated with adipogenesis and lipid metabolism. Further characterization revealed that both genders had reductions in VO2, VCO2, and RER, whereas females also had reduced heat production. Noggin was also reduced in diet-induced obesity in inbred mice consistent with the obesity phenotype of the Noggin-deficient mice.ConclusionsBMP signaling regulates female and male adipogenesis through different metabolic pathways. Modulation of adipose tissue metabolism by select BMP antagonists may be a strategy for long-term regulation of age-related weight gain and obesity

The Number of X Chromosomes Causes Sex Differences in Adiposity in Mice

Sexual dimorphism in body weight, fat distribution, and metabolic disease has been attributed largely to differential effects of male and female gonadal hormones. Here, we report that the number of X chromosomes within cells also contributes to these sex differences. We employed a unique mouse model, known as the “four core genotypes,” to distinguish between effects of gonadal sex (testes or ovaries) and sex chromosomes (XX or XY). With this model, we produced gonadal male and female mice carrying XX or XY sex chromosome complements. Mice were gonadectomized to remove the acute effects of gonadal hormones and to uncover effects of sex chromosome complement on obesity. Mice with XX sex chromosomes (relative to XY), regardless of their type of gonad, had up to 2-fold increased adiposity and greater food intake during daylight hours, when mice are normally inactive. Mice with two X chromosomes also had accelerated weight gain on a high fat diet and developed fatty liver and elevated lipid and insulin levels. Further genetic studies with mice carrying XO and XXY chromosome complements revealed that the differences between XX and XY mice are attributable to dosage of the X chromosome, rather than effects of the Y chromosome. A subset of genes that escape X chromosome inactivation exhibited higher expression levels in adipose tissue and liver of XX compared to XY mice, and may contribute to the sex differences in obesity. Overall, our study is the first to identify sex chromosome complement, a factor distinguishing all male and female cells, as a cause of sex differences in obesity and metabolism

Urbanisation generates multiple trait syndromes for terrestrial animal taxa worldwide

Cities can host significant biological diversity. Yet, urbanisation leads to the loss of habitats, species, and functional groups. Understanding how multiple taxa respond to urbanisation globally is essential to promote and conserve biodiversity in cities. Using a dataset encompassing six terrestrial faunal taxa (amphibians, bats, bees, birds, carabid beetles and reptiles) across 379 cities on 6 continents, we show that urbanisation produces taxon-specific changes in trait composition, with traits related to reproductive strategy showing the strongest response. Our findings suggest that urbanisation results in four trait syndromes (mobile generalists, site specialists, central place foragers, and mobile specialists), with resources associated with reproduction and diet likely driving patterns in traits associated with mobility and body size. Functional diversity measures showed varied responses, leading to shifts in trait space likely driven by critical resource distribution and abundance, and taxon-specific trait syndromes. Maximising opportunities to support taxa with different urban trait syndromes should be pivotal in conservation and management programmes within and among cities. This will reduce the likelihood of biotic homogenisation and helps ensure that urban environments have the capacity to respond to future challenges. These actions are critical to reframe the role of cities in global biodiversity loss.info:eu-repo/semantics/publishedVersio

Connectivité des paysages urbains et faune épigée (approche multi-échelles et multi-taxons)

Des avancées scientifiques sont nécessaires pour limiter l impact qu exerce l urbanisation croissante sur l environnement et comprendre le fonctionnement de la biodiversité urbaine. Dans cette thèse, nous avons analysé les effets à différentes échelles spatiales sur les patrons d organisation de plusieurs taxons appartenant à la faune épigée, suivant trois axes : (1) étudier les communautés à l échelle d une grande agglomération, (2) étudier l effet des corridors sur la dispersion et (3) modéliser la dispersion. Nous avons mis en évidence un effet majeur de l urbanisation des paysages sur les communautés, plus important pour les espèces forestières qui sont remplacées par des espèces plus généralistes. Les corridors, en favorisant la dispersion permettent, pour partie, d y remédier. Ces résultats ont été confirmés par le modèle de dispersion. Ces résultats ouvrent des perspectives dans la spatialisation du fonctionnement des communautés.Scientific insights are needed to limit the negative effects of urbanization and improve urban biodiversity. Thus, we analysed the effects of landscape on several ground dwelling communities (multi taxa approach). We organized our research following three main axis: (1) response along an urbanization gradient, (2) the effect of corridors on the dispersal among urban landscapes and (3) simulation of the corridor effect using an individual based model (IBM). We observed strong and negative effects of the urbanized landscapes, stronger for forest specialist species which are replaced by more generalist species along the gradient. We highlighted a positive effect of corridors with some differences between taxa that could be explained by variation in their dispersal capabilities, confirmed by the model. The IBM has confirmed these results. This study opens new doors on the spatial configuration of local communities within the landscapes.PARIS-Museum Hist.Naturelle (751052304) / SudocSudocFranceF

Bird feeders may sustain feral Rose-ringed parakeets Psittacula krameri in temperate Europe

International audienceThe Rose-ringed parakeet Psittacula krameri, a bird species of subtropical origin, has established feral populations in temperate Europe. We analysed the feeding habits of Rose-ringed parakeets near Paris, France, in order to assess if food provided by humans might contribute to the success of this invasive bird species. We considered 87 feeding events performed during 2002 -2007 and 247 feeding events performed during March -November 2008. We recorded the consumption of seeds, buds and fruits from many native and introduced shrubs and trees, and the use of bird feeders in private and public gardens throughout the year. We followed four radio-equipped birds for 150 hours during September -December 2008, which spent about half of their feeding time at bird feeders. This confirmed the importance of bird feeders in the diet of the Rose-ringed parakeet. Our study underlines the opportunistic granivorous-frugivorous character of this parakeet species and the possible role of human food sources in the success of its establishment in many cities across temperate Europe

Bias and perspectives in insect conservation : A European scale analysis

International audienceInsects are among the most diverse and abundant organisms on Earth, and they play a major role in ecosystem functioning. To protect them from decline, some conservation measures have been put in place, based primarily on threatened species lists. This is the case in Europe, where 123 of the 105,000 known European insect species are currently protected. Yet how were these few species selected? Are those species representative of the European entomofauna? Is it possible for a conservation policy based on the protection of only 0.12% of described species to be effective?In this study, we aimed to measure bias in the selection of species for conservation by comparing protected and unprotected species in Europe. To this end, we considered 15 characteristics divided into five main categories: ‘Taxonomy’, ‘Morphology’, ‘Diet’, ‘Knowledge’ and ‘Distribution’. We investigated bias in species selection and found that protected species were significantly larger, better known, more widespread and more multicoloured than a randomly selected set of unprotected species. Moreover, butterflies, dragonflies and grasshoppers were overrepresented, as were nectarivorous and saproxylophagous species. In contrast, Hymenopterans and Dipterans, together representing > 40% of European entomofauna, do not appear on the current list of protected species.To address this bias, we propose recommendations to improve the protection of insects at the European scale, including making lists more ‘dynamic’, introducing new criteria, and a paradigm shift towards conserving assemblages and ecological function. Existing technical and societal means could be used to achieve an integrative conservation approach for insects

Author's personal copy Green corridors in urban landscapes affect the arthropod communities of domestic gardens

International audiencea journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. In most cases authors are permitted to post their version of the article (e.g. in Word or Tex form) to their personal website or institutional repository. Authors requiring further information regarding Elsevier's archiving and manuscript policies are encouraged to visit: a b s t r a c t Ecological corridors are landscape elements that prevent the negative effects of fragmentation. However, their effectiveness has never been clearly validated in urban landscapes. We analysed the role of green corridors in an urban context by comparing metacommunities of arthro-pods in (i) woodlots considered as sources of species, (ii) woody corridors and domestic gardens that are (iii) connected (CG) or (iv) disconnected to corridors (DG) and taking into account the connectivity of the matrix. We trapped 3 taxa of arthropods – spiders, carabids and staphylinids – because they are sensitive to fragmentation but with different dispersal capabilities. We analysed their species richness, abundance and taxonomic and functional composition. For the 3 taxa, the taxonomic and functional compositions of communities in CG were closer to those of the corridor and the source than those of DG. Woodland species were associated with source, corridor and CG. A lower abundance in DG was revealed for staphylinids and spiders. Lower species richness in DG was observed for staphylinids. The differences between taxa could be explained by the dispersal capabilities of the species and by their various responses to landscape structures. For carabids, processes at a wider scale could be respon-sible for their rarity in sources and, consequently, in gardens. For spiders, the colonisation from other sources could explain the high species richness found in disconnected gardens. Our results suggest that the role of corridors is crucial for enhancing biodiversity in green spaces such as domestic gardens. Our results clarify the effectiveness of corridors in urban landscapes and have direct implications for the ecological management of cities