Involvement of plasmalogens in post-natal retinal vascular development

Objective: Proper development of retinal blood vessels is essential to ensure sufficient oxygen and nutrient supplies to the retina. It was shown that polyunsaturated fatty acids (PUFAs) could modulate factors involved in tissue vascularization. A congenital deficiency in ether-phospholipids, also termed "plasmalogens'', was shown to lead to abnormal ocular vascularization. Because plasmalogens are considered to be reservoirs of PUFAs, we wished to improve our understanding of the mechanisms by which plasmalogens regulate retinal vascular development and whether the release of PUFAs by calcium-independent phospholipase A2 (iPLA2) could be involved. [br/]Methods and Results: By characterizing the cellular and molecular steps of retinal vascular development in a mouse model of plasmalogen deficiency, we demonstrated that plasmalogens modulate angiogenic processes during the early phases of retinal vascularization. They influence glial activity and primary astrocyte template formation, endothelial cell proliferation and retinal vessel outgrowth, and impact the expression of the genes involved in angiogenesis in the retina. These early defects led to a disorganized and dysfunctional retinal vascular network at adult age. By comparing these data to those obtained on a mouse model of retinal iPLA2 inhibition, we suggest that these processes may be mediated by PUFAs released from plasmalogens and further signalling through the angiopoietin/tie pathways. [br/]Conclusions: These data suggest that plasmalogens play a crucial role in retinal vascularization processes

Le suicide chez les jeunes adultes de sexe masculin au Québec : Psychopathologie et utilisation des services médicaux

On a apparié 75 jeunes gens de 18 à 35 ans qui s'étaient suicidés à 75 autres, toujours en vie, en fonction de l'âge, de la résidence, du statut conjugal et professionnel. Pour chacun des groupes, un répondant principal a été interviewé, et les dossiers médicaux ainsi que ceux du coroner ont été examinés afin de reconstituer le profit psychologique des intéressés et leur utilisation des services. À six mois, la prévalence de tous les diagnostics d'axe (selon le DSMIH-R) était de 88,8 % pour le groupe des suicidés et de 37,3 % pour le groupe témoin. Parmi les suicidés, 38,7 % souffraient de dépression majeure, 24 % de dépendance à l'alcool, et 28,7 % aux drogues. La personnalité borderline a été identifiée chez 28% des suicidés contre 4% du groupe témoin. Chez les suicidés, 42,5 % avaient consulté un professionnel de la santé mentale dans l'année précédente, contre 5 % chez les témoins. Cependant, la grande majorité des suicidés (78,5%) avaient consulté un professionnel de la santé, tel un omnipraticien, contre 73,2 % chez les témoins.Seventy five young male adults between the age of 18 and 35 who had committed suicide were compared with 75 male adults still alive matched for age, residence, marital and employment status. For each group a principal respondent was interviewed in order to reconstitute the psychological profile of each individual, as well as their utilisation of health services. This was completed by the study of the coroner's reports and the medical records when available. At six months the prevalence for all axis diagnosis was 88.8% for the suicide group and 37.3% for the control group. Among the subjects who had commited suicide 38.7% were afflicted by major depression, 24% by alcohol dependency and 28.7% were dependent on drugs. Borderline personalities were present in 28% of the suicide group compared to 5% in the control group. Forty five percent (45%) of the subjects who had killed themselves had consulted a mental health professional in the year preceding the suicide compared to 5% in the control group. However, 78.5% of the suicide group had consulted during the same period a health professional compared to 73.3% of the controls

Cholesterol metabolism, autophagy and aging

National audienc

First Step to Manage Migration to Siemens S7-15XX PLCs using TANGO Framework

International audienceOver the past years, SOLEIL* uses SIEMENS PLCs** as a standard for signal monitoring and security. SOLEIL is today thinking about a major upgrade of the facilities, and has to adapt its organization to face efficient operation and R&D. In this context, automation experts are now merged in a single group. In a middle term, migration from the existing 3XX series PLCs to the new 15XX series will be necessary. As the new 15XX series PLCs do not support Fetch/Write protocol anymore, a first step is the upgrade of TANGO*** PLCServer. This software device ensures data exchange with supervisory applications using TANGO infrastructure. It opens multiple TCP/IP connections to the PLC hardware, manages asynchronous communication to read/write PLC Datablocks and acts as a server for other clients. The upgrade of PLCServer is based on Snap7**** open source Ethernet communication suite for interfacing with Siemens PLCs using the S7 native protocol. This paper details the evolutions, performances and limitations of this new version of the PLCServer

Fructose diet induced short-term impairment of cone sensitivity and gene expression in rat retina

National audienceAbstract: Purpose A high fructose diet has been widely used to trigger insulin resistance in rodent; insulin resistance is one of the major risk factor for the development of type 2 diabetes. Thirty to 40% of diabetic patients develop diabetic retinopathy. In this study, we aimed to evaluate the short-term effect, at 1, 3, 5, 8 days, of a 60% fructose diet, on photoreceptor sensitivity and gene expression in the retina of Brown Norway rats. Methods: Flicker electroretinograms (8Hz) were recorded under anesthesia, from both eyes simultaneously in order to study sensitivity of photoreceptors. Then, rats were euthanized and enucleated. Retinae and posterior poles were collected to analyze gene expression by RT-PCR. We specifically focused on 45 genes involved in cholesterol homeostasis, lipid trafficking, vascular changes and inflammation. Results: Our data showed that a short period of fructose feeding induced early changes in retinal functionality and homeostasis. Interestingly, we reported a partial loss of cone sensitivity after 8 days of feeding rats with the high-fructose diet. No effect was found in rod sensitivity. Conclusion: These findings are consistent with the sensibility and susceptibility of cones to dietary changes. These data deserve further investigations on the cross-talk between cones and rods upon metabolic changes associated with aging

Effects of 24s-hydroxycholesterol on primary glial Müller cells. New insights on Müller cells function and cholesterol homeostasis in the retina

Purpose: Müller cells are macroglial cells in the retina. These cells express various proteins known to undergo glutamate clearance, which dysfunction may be involved in the loss of retinal ganglion cells (RGC) in the course of glaucoma. In neurons and especially in RGC, 24S-hydroxycholesterol (24SOH) is a metabolite produced by conversion of cholesterol by cholesterol 24S-hydroxylase (CYP46A1). This process participates to cholesterol homeostasis by facilitating the removal of cholesterol from neurons. 24SOH might be a signal molecule ensuring the cross-talk between neurons and glia, and putatively between RGC and glia. The aim of our study was to emphasize the response of primary Müller cells to 24SOH.Methods: Retinas from 10-12 day post-natal Long Evans rats were dissected after enzymatic digestion and seeded into culture dishes. Cells were grown in DMEM (5mM glucose and 2mM glutamine) + 10% FCS at 37°C. At passage 4, Müller cells were incubated with 10, 50 and 100µM 24SOH for 24h. By means of comparison, Müller cells were triggered with 2, 10, 20 ng/µL IL1β and 25mM glucose. Cellular viability was assessed by MTT test. Cholesterol and 24SOH were measured in cell pellets and culture supernatants by isotope dilution gas chromatography-mass spectrometry using internal deuterated standard. Cytokines and chemokines were measured by Luminex® in cell pellets and culture supernatants. The expression of genes involved in lipid metabolism and glial activation was analyzed by RT-qPCR.Results: Cholesterol synthesis was reduced by 39% (10µM 24SOH) and 65% (50 and 100µM 24SOH) compared to controls and did not vary in cells incubated with IL1β and high glucose. The analysis of 24SOH in cells and supernatants revealed the capacity of Müller cells to metabolize 24SOH. MCP-1 and VEGF were increased in cells incubated with 24SOH only (from x1.75 at 10µM compared to controls to x4 at 50 and 100µM) but not in culture supernatants. 24SOH up-regulated the expression of CYP46A1, Ccl-2 (MCP-1), Slc1a2 (EAAT2), GFAP and genes involved in cholesterol transport.Conclusions: 24SOH, used in our in vitro study to mimic the stress of RGC, was found to be actively metabolized by Müller cells and to reduce cholesterol biosynthesis therein. This process may contribute to cholesterol homeostasis in the retina and to Müller cells reactivity in the course of RGC loss and glaucoma

Involvement of plasmalogens and iPLA2 in the control of post-natal retinal vascular development in mice

International audiencePurpose: The correct development of retinal blood vessels is essential to ensure vision process through sufficient oxygen and nutrient supplies to the retina. It was shown that polyunsaturated fatty acids (PUFAs) could modulate factors involved in tissue vascularization. A congenital deficiency in ether-phospholipids also termed as "plasmalogens" was shown to lead to abnormal ocular vascularization. Because plasmalogens are considered as reservoirs of PUFAs, we wanted to better understand the mechanisms by which plasmalogens may regulate retinal vascular development through the release of PUFAs by a calcium-independent phospholipase A2 (iPLA2). Methods: Retinal vascular development was followed in a mouse model of plasmalogen deficiency (DAPAT mice) as well as in a mouse model of retinal iPLA2 inhibition. Retinas were collected from birth until the age of 21 days. They were either flat-mounted and immuno-labelled to visualize the cells involved in vessel formation, or used to determine the expression of genes involved in inflammation and angiogenesis. Results: The lack of plasmalogens was associated to defects in angiogenic processes during early phases of retinal vascular development. Particularly, the absence of plasmalogens influenced astroglial activity during the primary astrocyte template formation, promoted endothelial cell proliferation during sprouting angiogenesis, and impacted the expression of genes involved in angiopoietin/tie pathways. These early defects led to a disorganized and dysfunctional retinal vascular network at adult age. As mice in which iPLA2 was inhibited exhibited a similar vascular phenotype when compared to DAPAT mice, we suggest that these processes may be mediated by PUFA release from plasmalogens and further signalling through angiopoietin/tie pathways. Conclusions: These data suggest a crucial role of plasmalogens during the formation of retinal vessels

Plasmalogens in the regulation of retinal vascular development: design of a mouse model with chemical inhibition of IPLA2

Plasmalogens in the regulation of retinal vascular development: design of a mouse model with chemical inhibition of IPLA2. annual meeting of the association-for-research-in-vision-and-ophthalmology (ARVO

Characterization of plasmalogens in retinal glial cells

Purpose: Plasmalogens (or ether-lipids) constitute a particular class of glycerophospholipids that are characterized by the presence of a vinyl-ether bond at the sn-1 position of the glycerol backbone and by the preferential esterification of polyunsaturated fatty acids (PUFAs) at the sn-2 position. Although their exact functions remain enigmatic, previous data from our laboratory suggest that plasmalogens play crucial functions during retinal vessel development by affecting astrocyte template formation (Saab et al PLoSONE 2014;9(6):e101076). The aim of this study was to better characterize plasmalogens in the retina and to determine which cells are responsible for plasmalogens production within the populations of retinal glial cells.Methods: Retinal Müller cells and astrocytes were isolated from eyes of Wistar rats aged from 12 to 21 days and cultured in DMEM medium. The presence of dihydroxyacetone-phosphate acyltransferase (DHAP-AT), the key enzyme of plasmalogen biosynthesis, was evaluated by western-blotting in each cell type. After lipid extraction, the cellular content of plasmalogens was determined by gas chromatography coupled to flame ionization detection (GC-FID). Furthermore, DHAP-AT immunostainings were performed on cultured cells as well as on retinal sections from eyes of C57BL/6 mice.Results: Immunohistochemistry revealed that DHAP-AT protein was present in the inner and the outer plexiform layers, as well as in photoreceptor inner segments. Immunostainings and western-blot analyses on primary cultures showed that DHAP-AT was highly expressed in Müller cells. Lipid analyses revealed that the levels of plasmalogens were higher in Müller cells than in astrocytes and the whole retina.Conclusions: These results highlight the differences between astrocytes and Müller cells in plasmalogen levels and key-enzyme in plasmalogen synthesis. Plasmalogens-dependent signalling pathways in the retina may therefore be specifically initiated in Müller cells. Further studies are needed to characterize the cell pathways activated by plasmalogens catabolism in Müller and neighbouring cells