Mise au point de microparticules polysaccharides injectables pour l'imagerie moléculaire de pathologies artérielles

Cardiovascular diseases and their consequences constitute nowadays a major health issue. Their treatment could be substantially improved with the development of new non invasive diagnostic techniques. The aim of this doctoral project is to develop injectable into blood stream polysaccharide microparticles that would permit molecular imaging of arterial pathologies. From an emulsion- crosslinking process, we synthesized these microparticles which are on the one hand functionalized with fucoidan to target P-Selectin which is expressed at damaged arterial wall, and on the other hand combined with contrast agents to bring an imaging signal. We developed 2 molecular imaging tools dedicated to 2 classical medical imaging modalities. In order to track the microparticles by single photon emission computed tomography, we radiolabeled them with technetium 99m and to detect them by MRI, we loaded them with superparamagnetic nanoparticles of iron oxide. We then have validated the efficiency of these 2 molecular imaging tools with preclinical studies of in vivo small animal imaging of arterial disease models. The obtained results are very promising and these 2 molecular imaging tools have a strong clinical potential for the diagnosis of arterial pathologies. We also have observed that the microparticles tend to migrate though the damaged arterial wall. This specific property could turn out to be very interesting for future works which will consist in using this technology to convey therapeutic molecules directly into the core of the arterial pathologies.Les pathologies cardiovasculaires et leurs conséquences représentent actuellement un problème de santé publique majeur dont la prise en charge pourrait être considérablement améliorée par le développement de nouvelles méthodes de diagnostic non invasives. Ce projet doctoral vise à développer des microparticules polysaccharides injectables dans la circulation sanguine permettant l’imagerie moléculaire des pathologies artérielles. Grâce à un procédé d’émulsion-réticulation, nous avons synthétisé ces microparticules qui sont d’une part fonctionnalisées avec du fucoïdane afin de pouvoir cibler la P-Sélectine qui est une molécule d’adhésion exprimée au niveau de la paroi artérielle lésée, et d’autre part, conjuguées à des agents de contraste afin d’apporter un signal en imagerie. Nous avons alors développé 2 outils d’imagerie moléculaire propres à 2 modalités classiques d’imagerie médicale. Afin de suivre les microparticules en tomographie par émission monophotonique de positons (TEMP), nous les avons radiomarquées avec du technétium 99m et pour les détecter en imagerie par résonance magnétique (IRM), nous les avons chargées avec des nanoparticules d’oxyde de fer superparamagnétiques. Nous avons ensuite validé l’efficacité de ces 2 outils d’imagerie moléculaire avec des essais précliniques en imagerie in vivo chez le petit animal sur des modèles de pathologies artérielles. Les résultats obtenus sont très encourageants et ces 2 outils d’imagerie moléculaire ont un fort potentiel clinique pour le diagnostic des pathologies artérielles. Nous avons également observé que les microparticules migrent dans la paroi artérielle dégradée au niveau des pathologies étudiées. Cette propriété singulière pourrait s’avérer très intéressante pour les futurs travaux qui consisteront à utiliser ce support pour véhiculer des molécules thérapeutiques au cœur des différentes pathologies artérielles

The Eukaryotic Promoter Database (EPD): recent developments

The Eukaryotic Promoter Database (EPD) is an annotated non-redundant collection of eukaryotic POL II promoters, for which the transcription start site has been determined experimentally. Access to promoter sequences is provided by pointers to positions in nucleotide sequence entries. The annotation part of an entry includes description of the initiation site mapping data, cross-references to other databases, and bibliographic references. EPD is structured in a way that facilitates dynamic extraction of biologically meaningful promoter subsets for comparative sequence analysis. Recent efforts have focused on exhaustive crossreferencing to the EMBL nucleotide sequence database, and on the improvement of the WWW-based user interfaces and data retrieval mechanisms. EPD can be accessed at http://www.epd.isb-sib.c

Towards the optimal use of an existing MRE electrical network from an electrothermal perspective

International audienc

Identification of TBK1 complexes required for the phosphorylation of IRF3 and the production of interferon β

The double-stranded RNA mimetic poly(I:C) and lipopolysaccharide (LPS) activate Toll-like receptors 3 (TLR3) and TLR4, respectively, triggering the activation of TANK (TRAF family member-associated NF-κB activator)-binding kinase 1 (TBK1) complexes, the phosphorylation of interferon regulatory factor 3 (IRF3) and transcription of the interferon β (IFNβ) gene. Here, we demonstrate that the TANK–TBK1 and optineurin (OPTN)–TBK1 complexes control this pathway. The poly(I:C)- or LPS-stimulated phosphorylation of IRF3 at Ser396 and production of IFNβ were greatly reduced in bone marrow-derived macrophages (BMDMs) from TANK knockout (KO) mice crossed to knockin mice expressing the ubiquitin-binding-defective OPTN[D477N] mutant. In contrast, IRF3 phosphorylation and IFNβ production were not reduced significantly in BMDM from OPTN[D477N] knockin mice and only reduced partially in TANK KO BMDM. The TLR3/TLR4-dependent phosphorylation of IRF3 and IFNβ gene transcription were not decreased in macrophages from OPTN[D477N] crossed to mice deficient in IκB kinase ε, a TANK-binding kinase related to TBK1. In contrast with the OPTN–TBK1 complex, TBK1 associated with OPTN[D477N] did not undergo phosphorylation at Ser172 in response to poly(I:C) or LPS, indicating that the interaction of ubiquitin chains with OPTN is required to activate OPTN–TBK1 in BMDM. The phosphorylation of IRF3 and IFNβ production induced by Sendai virus infection were unimpaired in BMDM from TANK KO × OPTN[D477N] mice, suggesting that other/additional TBK1 complexes control the RIG-I-like receptor-dependent production of IFNβ. Finally, we present evidence that, in human HACAT cells, the poly(I:C)-dependent phosphorylation of TBK1 at Ser172 involves a novel TBK1-activating kinase(s)

Muscle-Specific Adaptations, Impaired Oxidative Capacity and Maintenance of Contractile Function Characterize Diet-Induced Obese Mouse Skeletal Muscle

BACKGROUND:The effects of diet-induced obesity on skeletal muscle function are largely unknown, particularly as it relates to changes in oxidative metabolism and morphology. PRINCIPAL FINDINGS:Compared to control fed mice, mice fed a high fat diet (HFD; 60% kcal: fat) for 8 weeks displayed increased body mass and insulin resistance without overt fasting hyperglycemia (i.e. pre-diabetic). Histological analysis revealed a greater oxidative potential in the HFD gastrocnemius/plantaris (increased IIA, reduced IIB fiber-type percentages) and soleus (increased I, IIA cross-sectional areas) muscles, but no change in fiber type percentages in tibialis anterior muscles compared to controls. Intramyocellular lipid levels were significantly increased relative to control in HFD gastrocnemius/plantaris, but were similar to control values in the HFD soleus. Using a novel, single muscle fiber approach, impairments in complete palmitate and glucose oxidation (72.8+/-6.6% and 61.8+/-9.1% of control, respectively; p<0.05) with HFD were detected. These reductions were consistent with measures made using intact extensor digitorum longus and soleus muscles. Compared to controls, no difference in succinate dehydrogenase or citrate synthase enzyme activities were observed between groups in any muscle studied, however, short-chain fatty acyl CoA dehydrogenase (SCHAD) activity was elevated in the HFD soleus, but not tibialis anterior muscles. Despite these morphological and metabolic alterations, no significant difference in peak tetanic force or low-frequency fatigue rates were observed between groups. CONCLUSIONS:These findings indicate that HFD induces early adaptive responses that occur in a muscle-specific pattern, but are insufficient to prevent impairments in oxidative metabolism with continued high-fat feeding. Moreover, the morphological and metabolic changes which occur with 8 weeks of HFD do not significantly impact muscle contractile properties

Marine Antitumor Drugs: Status, Shortfalls and Strategies

Cancer is considered as one of the deadliest diseases in the medical field. Apart from the preventive therapies, it is important to find a curative measure which holds no loopholes and acts accurately and precisely to curb cancer. Over the past few decades, there have been advances in this field and there are many antitumor compounds available on the market, which are of natural as well as synthetic origin. Marine chemotherapy is well recognized nowadays and profound development has been achieved by researchers to deal with different molecular pathways of tumors. However, the marine environment has been less explored for the production of safe and novel antitumor compounds. The reason is a number of shortfalls in this field. Though ample reviews cover the importance and applications of various anticancerous compounds from marine natural products, in the present review, we have tried to bring the current status of antitumor research based on marine inhibitors of cancer signaling pathways. In addition, focus has been placed on the shortfalls and probable strategies in the arena of marine antitumor drug discovery

Effects of fatigue of plantarflexors on control and performance in vertical jumping

INTRODUCTION: We investigated the effects of a mismatch between control and musculoskeletal properties on performance in vertical jumping. METHODS: Six subjects performed maximum-effort vertical squat jumps before (REF) and after the plantarflexors of the right leg had been fatigued (FAT) while kinematic data, ground reaction forces, and EMG of leg muscles were collected. Inverse dynamics was used to calculate the net work at joints, and EMG was rectified and smoothed to obtain the smoothed rectified EMG (SREMG). The jumps of the subjects were also simulated with a musculoskeletal model comprising seven body segments and 12 Hill-type muscles, and having as only input muscle stimulation. RESULTS: Jump height was approximately 6 cm less in FAT jumps than in REF jumps. In FAT jumps, peak SREMG level was reduced by more than 35% in the right plantarflexors and by approximately 20% in the right hamstrings but not in any other muscles. In FAT jumps, the net joint work was reduced not only at the right ankle (by 70%) but also at the right hip (by 40%). Because the right hip was not spanned by fatigued muscles and the reduction in SREMG of the right hamstrings was relatively small, this indicated that the reduction in performance was partly due to a mismatch between control and musculoskeletal properties. The differences between REF and FAT jumps of the subjects were confirmed and explained by the simulation model. Reoptimization of control for the FAT model caused performance to be partly restored by approximately 2.5 cm. CONCLUSION: The reduction in performance in FAT jumps was partly due to a mismatch between control and musculoskeletal properties. © 2011 The American College of Sports Medicine

Loss-of-function mutations in UDP-Glucose 6-Dehydrogenase cause recessive developmental epileptic encephalopathy

AbstractDevelopmental epileptic encephalopathies are devastating disorders characterized by intractable epileptic seizures and developmental delay. Here, we report an allelic series of germline recessive mutations in UGDH in 36 cases from 25 families presenting with epileptic encephalopathy with developmental delay and hypotonia. UGDH encodes an oxidoreductase that converts UDP-glucose to UDP-glucuronic acid, a key component of specific proteoglycans and glycolipids. Consistent with being loss-of-function alleles, we show using patients’ primary fibroblasts and biochemical assays, that these mutations either impair UGDH stability, oligomerization, or enzymatic activity. In vitro, patient-derived cerebral organoids are smaller with a reduced number of proliferating neuronal progenitors while mutant ugdh zebrafish do not phenocopy the human disease. Our study defines UGDH as a key player for the production of extracellular matrix components that are essential for human brain development. Based on the incidence of variants observed, UGDH mutations are likely to be a frequent cause of recessive epileptic encephalopathy.</jats:p

Loss-of-function mutations in UDP-Glucose 6-Dehydrogenase cause recessive developmental epileptic encephalopathy

Developmental epileptic encephalopathies are devastating disorders characterized by intractable epileptic seizures and developmental delay. Here, we report an allelic series of germline recessive mutations in UGDH in 36 cases from 25 families presenting with epileptic encephalopathy with developmental delay and hypotonia. UGDH encodes an oxidoreductase that converts UDP-glucose to UDP-glucuronic acid, a key component of specific proteoglycans and glycolipids. Consistent with being loss-of-function alleles, we show using patients’ primary fibroblasts and biochemical assays, that these mutations either impair UGDH stability, oligomerization, or enzymatic activity. In vitro, patient-derived cerebral organoids are smaller with a reduced number of proliferating neuronal progenitors while mutant ugdh zebrafish do not phenocopy the human disease. Our study defines UGDH as a key player for the production of extracellular matrix components that are essential for human brain development. Based on the incidence of variants observed, UGDH mutations are likely to be a frequent cause of recessive epileptic encephalopathy

Laparoscopy in management of appendicitis in high-, middle-, and low-income countries: a multicenter, prospective, cohort study.

BACKGROUND: Appendicitis is the most common abdominal surgical emergency worldwide. Differences between high- and low-income settings in the availability of laparoscopic appendectomy, alternative management choices, and outcomes are poorly described. The aim was to identify variation in surgical management and outcomes of appendicitis within low-, middle-, and high-Human Development Index (HDI) countries worldwide. METHODS: This is a multicenter, international prospective cohort study. Consecutive sampling of patients undergoing emergency appendectomy over 6 months was conducted. Follow-up lasted 30 days. RESULTS: 4546 patients from 52 countries underwent appendectomy (2499 high-, 1540 middle-, and 507 low-HDI groups). Surgical site infection (SSI) rates were higher in low-HDI (OR 2.57, 95% CI 1.33-4.99, p = 0.005) but not middle-HDI countries (OR 1.38, 95% CI 0.76-2.52, p = 0.291), compared with high-HDI countries after adjustment. A laparoscopic approach was common in high-HDI countries (1693/2499, 67.7%), but infrequent in low-HDI (41/507, 8.1%) and middle-HDI (132/1540, 8.6%) groups. After accounting for case-mix, laparoscopy was still associated with fewer overall complications (OR 0.55, 95% CI 0.42-0.71, p < 0.001) and SSIs (OR 0.22, 95% CI 0.14-0.33, p < 0.001). In propensity-score matched groups within low-/middle-HDI countries, laparoscopy was still associated with fewer overall complications (OR 0.23 95% CI 0.11-0.44) and SSI (OR 0.21 95% CI 0.09-0.45). CONCLUSION: A laparoscopic approach is associated with better outcomes and availability appears to differ by country HDI. Despite the profound clinical, operational, and financial barriers to its widespread introduction, laparoscopy could significantly improve outcomes for patients in low-resource environments. TRIAL REGISTRATION: NCT02179112