Fragile X mental retardation protein (FMRP) and metabotropic glutamate receptor subtype 5 (mGlu5) control stress granule formation in astrocytes

Fragile X syndrome (FXS) is a common form of intellectual disability and autism caused by the lack of Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein involved in RNA transport and protein synthesis. Upon cellular stress, global protein synthesis is blocked and mRNAs are recruited into stress granules (SGs), together with RNA-binding proteins including FMRP. Activation of group-I metabotropic glutamate (mGlu) receptors stimulates FMRP-mediated mRNA transport and protein synthesis, but their role in SGs formation is unexplored. To this aim, we pre-treated wild type (WT) and Fmr1 knockout (KO) cultured astrocytes with the group-I-mGlu receptor agonist (S)-3,5-Dihydroxyphenylglycine (DHPG) and exposed them to sodium arsenite (NaAsO2), a widely used inducer of SGs formation. In WT cultures the activation of group-I mGlu receptors reduced SGs formation and recruitment of FMRP into SGs, and also attenuated phosphorylation of eIF2α, a key event crucially involved in SGs formation and inhibition of protein synthesis. In contrast, Fmr1 KO astrocytes, which exhibited a lower number of SGs than WT astrocytes, did not respond to agonist stimulation. Interestingly, the mGlu5 receptor negative allosteric modulator (NAM) 2-methyl-6-(phenylethynyl)pyridine (MPEP) antagonized DHPG-mediated SGs reduction in WT and reversed SGs formation in Fmr1 KO cultures. Our findings reveal a novel function of mGlu5 receptor as modulator of SGs formation and open new perspectives for understanding cellular response to stress in FXS pathophysiology

Effect of mofezolac-galactose distance in conjugates targeting cyclooxygenase (COX)-1 and CNS GLUT-1 carrier

Neuroinflammation is the earliest stage of several neurological and neurodegenerative diseases. In the case of neurodegenerative disorders, it takes place about 15â 20 years before the appearance of specific neurodegenerative clinical symptoms. Constitutive microglial COX-1 is one of the pro-inflammatory players of the neuroinflammation. Novel compounds 3, 14 and 15 (Galmof0, Galmof5and Galmof11, respectively) were projected, and their synthetic methodologies developed, by linking by an ester bond, directly or through a C5 or C11 unit linker the highly selective COX-1 inhibitor mofezolac (COXs selectivity index > 6000) to galactose in order to obtain substances capable to cross blood-brain barrier (BBB) and control the CNS inflammatory response. 3, 14 and 15 (Galmofs) were prepared in good to fair yields. Galmof0(3) was found to be a selective COX-1 inhibitor (COX-1 IC50= 0.27 μM and COX-2 IC50= 3.1 μM, selectivity index = 11.5), chemically and metabolically stable, and capable to cross Caco-2 cell monolayer, resembling BBB, probing that its transport is GLUT-1-mediated. Furthermore, Galmof0(3) powerfully inhibits PGE2release higher than mofezolac (1) in LPS-stimulated mouse BV2 microglial cell line, a worldwide recognized neuroinflammation model. In addition, Fingerprints for Ligands and Proteins (FLAP) was used to explain the different binding interactions of Galmofs with the COX-1 active site

Fluorochrome Selection for Imaging Intraoperative Ovarian Cancer Probes

The identification and removal of all gross and microscopic tumor to render the patient disease free represents a huge challenge in ovarian cancer treatment. The presence of residual disease is an independent negative prognostic factor. Herein, we describe the synthesis and the “in vitro” evaluation of compounds as cyclooxygenase (COX)-1 inhibitors, the COX-1 isoform being an ovarian cancer biomarker, each bearing fluorochromes with different fluorescence features. Two of these compounds N-[4-(9-dimethylimino-9H-benzo[a]phenoxazin-5-ylamino) butyl]-2-(3,4-bis(4-methoxyphenyl)isoxazol-5-yl)acetamide chloride (RR11) and 3-(6-(4-(2-(3,4-bis(4-methoxyphenyl)isoxazole-5-yl)acetamido)butyl)amino-6-oxohexyl)-2-[7-(1,3-dihydro-1,1-dimethyl-3-ethyl 2H-benz[e]indolin-2-yl-idene)-1,3,5-heptatrienyl]-1,1-dimethyl-3-(6-carboxilato-hexyl)-1H-benz[e]indolium chloride, 23 (MSA14) were found to be potent and selective inhibitors of cyclooxygenase (COX)-1 “in vitro”, and thus were further investigated “in vivo”. The IC50 values were 0.032 and 0.087 µM for RR11 and 23 (MSA 14), respectively, whereas the COX-2 IC50 for RR11 is 2.4 µM while 23 (MSA14) did not inhibit COX-2 even at a 50 µM concentration. Together, this represented selectivity index = 75 and 874, respectively. Structure-based virtual screening (SBVS) performed with the Fingerprints for Ligands and Proteins (FLAP) software allowed both to differentiate highly active compounds from less active and inactive structures and to define their interactions inside the substrate-binding cavity of hCOX1. Fluorescent probes RR11 and 23 (MSA14), were used for preliminary near-infrared (NIR) fluorescent imaging (FLI) in human ovarian cancer (OVCAR-3 and SKOV-3) xenograft models. Surprisingly, a tumor-specific signal was observed for both tested fluorescent probes, even though this signal is not linked to the presence of COX-1.publishedVersio

Facile synthesis of novel lithium β-diketonate glyme adducts: the effect of molecular engineering on the thermal properties

International audienceNovel adducts of lithium hexafluoroacetylacetonato {Li(hfa)} with polyethers (monoglyme = {CH3OCH2CH2OCH3}, diglyme = {CH3O(CH2CH2O)2CH3}, triglyme = {CH3O(CH2CH2O)3CH3} and tetraglyme {CH3O(CH2CH2O)4CH3} have been synthesized through a single step reaction and characterized by FT-IR spectroscopy, 1H, and 13C NMR, single crystal X-ray diffraction studies along with thermal analysis

Stereochemistry and thermodynamics of the inclusion of aliphatic and aromatic anionic guests in a tetracationic calix[4]arene in acidic and neutral aqueous solutionswz

A cationic calix 1 H NMR and potentiometric data show that the host flexibility changes as a function of pH. 1 H NMR and isothermal titration calorimetry (ITC) studies, also supported by ESI-MS data, show that inclusion yields supramolecular complexes of the guestChost type only. Binding becomes weaker as the pH increases due to rigidification of the host in neutral aqueous solutions, and is enthalpically favoured for all the supramolecular complexes, regardless of pH

Three-dimensional network structures based on pyridylcalix[4]arene metal complexes

A new series of supramolecular assemblies is obtained through the interaction of 3-pyridylmethyl-calixarenes and copper or zinc ions. The complexes formed are characterized both in solution and in the solid state. The results offer appealing insights into how the steric crowding of the lower rim and different coordination modes of the metal centers have a great impact on the overall architecture of the complexes with the formation of monomeric, dimeric, or oligomeric/polymeric species