Design and Evaluation of Autophagy-Inducing Particles for the Treatment of Abnormal Lipid Accumulation

Autophagy is a fundamental housekeeping process by which cells degrade their components to maintain homeostasis. Defects in autophagy have been associated with aging, neurodegeneration and metabolic diseases. Non-alcoholic fatty liver diseases (NAFLDs) are characterized by hepatic fat accumulation with or without inflammation. No treatment for NAFLDs is currently available, but autophagy induction has been proposed as a promising therapeutic strategy. Here, we aimed to design autophagy-inducing particles, using the autophagy-inducing peptide (Tat-Beclin), and achieve liver targeting in vivo, taking NAFLD as a model disease. Polylactic acid (PLA) particles were prepared by nanoprecipitation without any surfactant, followed by surface peptide adsorption. The ability of Tat-Beclin nanoparticles (NP T-B) to modulate autophagy and to decrease intracellular lipid was evaluated in vitro by LC3 immunoblot and using a cellular model of steatosis, respectively. The intracellular localization of particles was evaluated by transmission electron microscopy (TEM). Finally, biodistribution of fluorescent NP T-B was evaluated in vivo using tomography in normal and obese mice. The results showed that NP T-B induce autophagy with a long-lasting and enhanced effect compared to the soluble peptide, and at a ten times lower dose. Intracellular lipid also decreased in a cellular model of NAFLD after treatment with T-B and NP T-B under the same dose conditions. Ultrastructural studies revealed that NP T-B are internalized and located in endosomal, endolysosomal and autolysosomal compartments, while in healthy and obese mice, NP T-B could accumulate for several days in the liver. Given the beneficial effects of autophagy-inducing particles in vitro, and their capacity to target the liver of normal and obese mice, NP T-B could be a promising therapeutic tool for NAFLDs, warranting further in vivo investigation

Density fluctuations of the ophiuroids Ophiothrix fragilis and Ophiocomina nigra in the Bay of Douarnenez, Brittany, France

International audiencen the Bay of Douarnenez, in a reference area surveyed for echinoderms, the relative abundance of epifaunal ophiuroids (Ophiothrix fragilis and Ophiocomina nigra) was estimated by dredging and video surveys. Two surveys were undertaken in 2008 and 2011, following a protocol similar to that used in a long-term survey conducted in the 1980s. The data were then compared between the two periods. The present observations demonstrate a recolonization of this site by these ophiuroids, which had almost disappeared between 1983 and 1988. However, although the mean densities of Ophiothrix fragilis were similar to those found prior to this general ophiuroid decrease, Ophiocomina nigra densities were much greater. This latter species not only increased significantly in density and bottom coverage in the reference area, but also showed strong juvenile recruitments on maerl beds and colonization of other bottoms of the bay at very high densities according to a geostatistical analysis. Further studies would be necessary to establish whether or not there is a cause-and-effect relationship between the increase of green algae in the bay and the development of this opportunistic species. © Marine Biological Association of the United Kingdom 2013

Cholesterol accumulation induced by acetylated LDL exposure modifies the enzymatic activities of the TCA cycle without impairing the respiratory chain functionality in macrophages

International audienceThe unregulated uptake of modified low-density lipoproteins (LDL) by macrophages leads to foam cell formation, promoting atherosclerotic plaque progression. The cholesterol efflux capacity of macrophages by the ATP-Binding Cassette transporters depends on the ATP mitochondrial production. Therefore, the mitochondrial function maintenance is crucial in limiting foam cell formation. Thus, we aimed to investigate the mechanisms involved in the mitochondrial dysfunction that may occur in cholesterol-laden macrophages. We incubated THP-1 macrophages with acetylated LDL (acLDL) to obtain cholesterol-laden cells or with mildly oxidized LDL (oxLDL) to generate cholesterol- and oxidized lipids-laden cells. Cellular cholesterol content was measured in each condition. Mitochondrial function was evaluated by measurement of several markers of energetic metabolism, oxidative phosphorylation, oxidative stress, mitochondrial biogenesis and dynamics. OxLDL-exposed macrophages exhibited a significantly reduced mitochondrial respiration and complexes I and III activities, associated to an oxidative stress state and a reduced mitochondrial DNA copy number. Meanwhile, acLDL-exposed macrophages featured an efficient oxidative phosphorylation despite the decreased activities of aconitase, isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. Our study revealed that mitochondrial function was differently impacted according to the nature of modified LDL. Exposure to cholesterol and oxidized lipids carried by oxLDL leads to a mitochondrial dysfunction in macrophages, affecting the mitochondrial respiratory chain functional capacity, whereas the cellular cholesterol enrichment induced by acLDL exposure results in a tricarboxylic acid cycle shunt while maintaining mitochondrial energetic production, reflecting a metabolic adaptation to cholesterol intake. These new mechanistic insights are of direct relevance to the understanding of the mitochondrial dysfunction in foam cells

Class 3 PI3K coactivates the circadian clock to promote rhythmic de novo purine synthesis

Metabolic demands fluctuate rhythmically and rely on coordination between the circadian clock and nutrient-sensing signalling pathways, yet mechanisms of their interaction remain not fully understood. Surprisingly, we find that class 3 phosphatidylinositol-3-kinase (PI3K), known best for its essential role as a lipid kinase in endocytosis and lysosomal degradation by autophagy, has an overlooked nuclear function in gene transcription as a coactivator of the heterodimeric transcription factor and circadian driver Bmal1-Clock. Canonical pro-catabolic functions of class 3 PI3K in trafficking rely on the indispensable complex between the lipid kinase Vps34 and regulatory subunit Vps15. We demonstrate that although both subunits of class 3 PI3K interact with RNA polymerase II and co-localize with active transcription sites, exclusive loss of Vps15 in cells blunts the transcriptional activity of Bmal1-Clock. Thus, we establish non-redundancy between nuclear Vps34 and Vps15, reflected by the persistent nuclear pool of Vps15 in Vps34-depleted cells and the ability of Vps15 to coactivate Bmal1-Clock independently of its complex with Vps34. In physiology we find that Vps15 is required for metabolic rhythmicity in liver and, unexpectedly, it promotes pro-anabolic de novo purine nucleotide synthesis. We show that Vps15 activates the transcription of Ppat, a key enzyme for the production of inosine monophosphate, a central metabolic intermediate for purine synthesis. Finally, we demonstrate that in fasting, which represses clock transcriptional activity, Vps15 levels are decreased on the promoters of Bmal1 targets, Nr1d1 and Ppat. Our findings open avenues for establishing the complexity for nuclear class 3 PI3K signalling for temporal regulation of energy homeostasis

How do people who use drugs receiving Opioid Medication Therapy perceive their treatment ? A multicentre study

International audienceAbstract Background The resurgence of heroin use and the misuse of pharmaceutical opioids are some of the reasons for a worldwide increase in opioid dependence. Opioid Medication Therapies (OMT) have amply demonstrated their efficacy. From a medical point of view, the main objectives of OMT concern medical and social outcomes, centred on risk reduction and the cessation of opioid use. But patient points of view can differ and few studies have explored opioid-dependent patient viewpoints on their OMT. This variable seems important to consider in a patient-centred approach. The aim of our study was to explore points of view of people who use drugs (PWUD) treated with OMT, in a large multicentre sample. Method A cross-sectional multicentre study explored the points of view of PWUD with Opioid Use Disorder following OMT. Data regarding the patients’ points of view were collected using a self-administered questionnaire developed by the scientific committee of the study. A descriptive analysis and an exploratory factor analysis were performed to explore the structure of items exploring patient viewpoints. Results 263 opioid dependent PWUD were included, a majority were men consuming heroin prior to being prescribed OMT. 68% were on methadone, 32% were on buprenorphine. Most PWUD identified a positive impact on their lives, with 92.8% agreeing or strongly agreeing that OMT had changed a lot of things in their lives. The exploratory factor analysis identified three factors: (F1) items related to points of views concerning the objectives and efficacy of OMT; (F2) items related to the legitimacy of OMT as a treatment compared to a drug, (F3) items related to experiences and relationships with OMT. Conclusion Patient viewpoints on efficacy were correlated with the pharmacological benefits of OMT and with the associated psychosocial measures. The implications of OMT in relationships, such as the feeling of being judged, concerned a majority. Points of view were ambivalent concerning the role of OMT as a treatment or as a drug. Involving patient points of view in therapeutic strategies decisions could help enhance positive views among PWUD on OMT and help PWUD towards their recovery. Trial registration: OPAL study was registered: (NCT01847729)

Emerging highly pathogenic H5 avian influenza viruses in France during winter 2015/16: phylogenetic analyses and markers for zoonotic potential

International audienceSeveral new highly pathogenic (HP) H5 avian influenza virus (AIV) have been detected in poultry farms from south-western France since November 2015, among which an HP H5N1. The zoonotic potential and origin of these AIVs immediately became matters of concern. One virus of each subtype H5N1 (150169a), H5N2 (150233) and H5N9 (150236) was characterised. All proved highly pathogenic for poultry as demonstrated molecularly by the presence of a polybasic cleavage site in their HA protein – with a sequence (HQRRKR/GLF) previously unknown among avian H5 HPAI viruses – or experimentally by the in vivo demonstration of an intravenous pathogenicity index of 2.9 for the H5N1 HP isolate. Phylogenetic analyses based on the full genomes obtained by NGS confirmed that the eight viral segments of the three isolates were all part of avian Eurasian phylogenetic lineage but differed from the Gs/Gd/1/96-like lineage. The study of the genetic characteristics at specific amino acid positions relevant for modulating the adaptation to and the virulence for mammals showed that presently, these viruses possess most molecular features characteristic of AIV and lack some major characteristics required for efficient respiratory transmission to or between humans. The three isolates are therefore predicted to have no significant pandemic potential