Different modulation of RPS6 phosphorylation by risperidone in striatal cells sub populations: involvement of the mTOR pathway in antipsychotic-induced extrapyramidal symptoms in mice

Objective: Acute extrapyramidal symptoms (EPS) are frequent and serious adverse reactions to antipsychotic (AP) drugs. Although the proposed mechanism is an excessive blockade of dopamine D2 receptors in the striatopallidal pathway of the striatum, previous studies implicated the mTOR pathway in the susceptibility to EPS. The objective of the present study is to analyze the mTOR-mediated response to risperidone in subpopulations of striatal neurons and its relationship to risperidone-induced motor side effects. Methods: Two mouse strains (A/J and DBA/2J) with different susceptibility to developing EPS were treated with risperidone 1 mg/kg for three consecutive days. Here we monitored, by double labeling immunohistochemistry, ribosomal protein S6 (rpS6) phosphorylation (Ser235/236 and Ser244/247 sites), a marker of mTOR signaling, in the striatonigral pathway (D1-medium spiny neurons (MSNs)), the striatopallidal pathway (D2-MSNs) and striatal cholinergic interneurons. Results: We found that EPS-resistant DBA/2J mice show higher baseline levels of phosphoactivated rpS6 protein in striatal MSNs, compared with EPS-prone A/J mice. Moreover, risperidone differentially targeted rpS6 phosphorylation in direct and indirect pathway neurons in a strain-specific manner: a significant decrease in the phosphorylation of rpS6 at Ser235/236 and Ser240/244 in DRD1-MSNs EPS-resistant DBA/2J mice after; and a significant increase of phospho-Ser235/236-rpS6 in the striatopallidal pathway of the EPS-prone A/J mice in response to risperidone. Conclusions: Our results reveal the vital role of genetic background in the response to risperidone, and point to the mTOR pathway as an important factor in EPS susceptibility. Keywords: Schizophrenia, Antipsychotic, Risperidone, Extrapyramidal symptoms. mTOR pathway, Striatum, Medium spiny neuron

Improving pharmacogenetic prediction of extrapyramidal symptoms induced by antipshycotics

In previous work we developed a pharmacogenetic predictor of antipsychotic (AP) induced extrapyramidal symptoms (EPS) based on four genes involved in mTOR regulation. The main objective is to improve this predictor by increasing its biological plausibility and replication. We re-sequence the four genes using next-generation sequencing. We predict functionality 'in silico' of all identified SNPs and test it using gene reporter assays. Using functional SNPs, we develop a new predictor utilizing machine learning algorithms (Discovery Cohort, N = 131) and replicate it in two independent cohorts (Replication Cohort 1, N = 113; Replication Cohort 2, N = 113). After prioritization, four SNPs were used to develop the pharmacogenetic predictor of AP-induced EPS. The model constructed using the Naive Bayes algorithm achieved a 66% of accuracy in the Discovery Cohort, and similar performances in the replication cohorts. The result is an improved pharmacogenetic predictor of AP-induced EPS, which is more robust and generalizable than the original

Analyse der Arzneimitteltherapie von Rheumapatienten im Erwachsenenalter : das Versorgungsgeschehen im Lichte der Leitlinienempfehlungen

The aim of this dissertation is to demonstrate the further developments in the provision of rheumatological health care with particular focus on evidence-based guideline recommendations. One of the issues to be examined is to identify gaps - defined as conditions of insufficient medical care between practical daily care and (theoretical) guideline recommendations differentiating various aspects of care. Are there still references about a lack of provison of medical care or is it possible to reveal further developments that can be assessed as positive respectively? Avenues for future action are to be pointed out against the background of these findings with regard to measures which have already been established as well as to aspired solutions in order to optimate the provision of rheumatological health care. A further glimpse of the future is disclosed by taking up the biosimilar-issue: As many bio-pharmaceuticals lose patent protection in coming years, biosimilar products are expected to play a key role in controlling pharmaceutical expenditure - while maintaining consistent quality of medical care. Assessing opportunities and challenges of these new medical products will round off this dissertation

Molecular properties of the BAR domain and role in the function of endophilins in the dynamics of intracellular compartments

Ce travail de thèse a été centré sur l étude des propriétés fonctionnelles d un domaine capable de déformer les membranes biologiques appelé domaine BAR (Bin/Amphiphysine/Rvs). Nous nous sommes essentiellement centré sur le rôle des propriétés moléculaires du domaine BAR d une famille de protéines à domaine SH3 appelées endophilines. L ensemble de ce travail de thèse aura principalement conduit à (1) montrer l importance de la dimérisation des séquences BAR dans la fonction des endophilines A sur les membranes cibles, (2) identifier une nouvelle cible membranaire des endophilines, la mitochondrie, compartiment sur lequel elles exercent une action dans le contrôle de la morphologie et de la dynamique, dans des contextes physiologiques normaux et/ou pathologiques, (3) identifier les endophilines A2 et B1 comme les cibles (par modification post-traductionnelle dont la nature reste encore à déterminer) d une nouvelle voie de signalisation entre la mitochondrie et le réticulum endoplasmique.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Single point mutation in the bin/amphiphysin/RVS (BAR) sequence of endophilin impairs dimerization, membrane shaping, and SRC homology 3 domain-mediated partnership.

International audienceBin/Amphiphysin/Rvs (BAR) domain-containing proteins are essential players in the dynamics of intracellular compartments. The BAR domain is an evolutionarily conserved dimeric module characterized by a crescent-shaped structure whose intrinsic curvature, flexibility and ability to assemble into highly ordered oligomers, contribute to inducing curvature of target membranes. Endophilins, diverging into A and B sub-groups, are BAR and SH3 domain-containing proteins. They exert activities in membrane dynamic processes such as endocytosis, autophagy, mitochondrial dynamics and permeabilization during apoptosis. Here, we report on the involvement of the third α-helix of endophilins A BAR sequence in dimerization and identify leucine 215 as a key residue within a network of hydrophobic interactions stabilizing the entire BAR dimer interface. With the combination of amino-terminal truncation retaining the high dimerization capacity of the third α-helices of endophilins A and leucine 215 substitution by aspartate (L215D), we demonstrate the essential role of BAR-sequence mediated dimerization on SH3 domain partnership. In comparison to wild type, full-length endophilin A2 heterodimers with one protomer bearing the L215D substitution, exhibit very significant changes in membrane-binding and shaping activities as well as dramatic decrease of SH3 domain partnership. This suggests that subtle changes in the conformation and/or rigidity of the BAR domain impact on both the control of membrane curvature and downstream binding to effectors. Finally, we show that expression, in mammalian cells, of endophilin A2 bearing the L215D substitution, impairs the endocytic recycling of transferrin receptors

Characterization of dequalinium as a XIAP antagonist that targets the BIR2 domain

8 páginas, 5 figuras, 1 tabla. PMID:21340509[PubMed]Inhibitor of apoptosis proteins (IAPs) regulate the activity of caspases in apoptosis. The human X chromosome-encoded IAP (XIAP) is one of the more potent members of the IAP family and it has been described as a central regulator of apoptosis. Thus, molecules that inhibit XIAP could offer therapeutic opportunities to treat unwanted apoptosis inhibition. In the present study we have applied the selective optimization of side activities (SOSA) approach to the discovery of XIAP inhibitors. In this sense, we have identified dequalinium hydrochloride (Dq) as an inhibitor of the XIAP/caspase-3 interaction both in vitro and in cellular assaysThis work was supported by grants from the Spanish Ministry of Science and Innovation (MICINN - BIO2007-60066), Generalitat Valenciana Prometeo 2010/005 (partially funded with ERDF) and Consolider-Ingenio 2010 (MICINN - CSD2008-00005C) to E.P.-P. We thank Susana Rubio and Alicia García-Jareño for technical assistance. Y. P.-R. was supported by a postdoctoral fellowship from National Autonomous University of Mexico and Consejo Superior de Investigaciones Científicas of Spain (UNAM-CSIC).Peer reviewe