Intronic elements associated with insomnia and restless legs syndrome exhibit cell-type-specific epigenetic features contributing to MEIS1 regulation

A highly evolutionarily conserved myeloid ecotropic viral integration site 1 (MEIS1) intronic region is strongly associated with restless legs syndrome (RLS) and insomnia. To understand its regulatory function, we dissected the region by analyzing chromatin accessibility, enhancer-promoter contacts, DNA methylation and expression quantitative trait locus (eQTLs) in different human neural cell types and tissues. We observed specific activity with respect to cell type and developmental maturation, indicating a prominent role for distinct highly conserved intronic elements in forebrain inhibitory neuron differentiation. Two elements were hypomethylated in neural cells with higher MEIS1 expression, suggesting a role of enhancer demethylation in gene regulation. MEIS1 eQTLs showed a striking modular chromosomal distribution, with forebrain eQTLs clustering in intron 8/9. Clustered regularly interspersed short palindromic repeats interference targeting of individual elements in this region attenuated MEIS1 expression, revealing a complex regulatory interplay of distinct elements. In summary, we found that MEIS1 regulation is organized in a modular pattern. Disease-associated intronic regulatory elements control MEIS1 expression with cell type and maturation stage specificity, particularly in the inhibitory neuron lineage. The precise spatiotemporal activity of these elements likely contributes to the pathogenesis of insomnia and RLS

Formation of highly stable multinuclear AgnSn clusters in zinc fingers disrupts their structure and function

Silver (Ag(I)) binding to consensus zinc fingers (ZFs) causes Zn(II) release inducing a gradual disruption of the hydrophobic core, followed by an overall conformational change and formation of highly stable AgnSn clusters. A compact eight-membered Ag4S4 structure formed by a CCCC ZF is the first cluster example reported for a single biological molecule. Ag(I)-induced conformational changes of ZFs can, as a consequence, affect transcriptional regulation and other cellular processes

In situ targeted activation of an anticancer agent using ultrasound-triggered release of composite droplets

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PLoS Genet

The retinoid X receptors (RXRs) are ligand-activated transcription factors which heterodimerize with a number of nuclear hormone receptors, thereby controlling a variety of (patho)-physiological processes. Although synthetic RXR ligands are developed for the treatment of various diseases, endogenous ligand(s) for these receptors have not been conclusively identified. We show here that mice lacking cellular retinol binding protein (Rbp1-/-) display memory deficits reflecting compromised RXR signaling. Using HPLC-MS and chemical synthesis we identified in Rbp1-/- mice reduced levels of 9-cis-13,14-dihydroretinoic acid (9CDHRA), which acts as an RXR ligand since it binds and transactivates RXR in various assays. 9CDHRA rescues the Rbp1-/- phenotype similarly to a synthetic RXR ligand and displays similar transcriptional activity in cultured human dendritic cells. High endogenous levels of 9CDHRA in mice indicate physiological relevance of these data and that 9CDHRA acts as an endogenous RXR ligand

Retinoid X receptor gamma signaling accelerates CNS remyelination

The molecular basis of CNS myelin regeneration (remyelination) is poorly understood. We generated a comprehensive transcriptional profile of the separate stages of spontaneous remyelination that follow focal demyelination in the rat CNS and found that transcripts that encode the retinoid acid receptor RXR-γ were differentially expressed during remyelination. Cells of the oligodendrocyte lineage expressed RXR-γ in rat tissues that were undergoing remyelination and in active and remyelinated multiple sclerosis lesions. Knockdown of RXR-γ by RNA interference or RXR-specific antagonists severely inhibited oligodendrocyte differentiation in culture. In mice that lacked RXR-γ, adult oligodendrocyte precursor cells efficiently repopulated lesions after demyelination, but showed delayed differentiation into mature oligodendrocytes. Administration of the RXR agonist 9-cis-retinoic acid to demyelinated cerebellar slice cultures and to aged rats after demyelination caused an increase in remyelinated axons. Our results indicate that RXR-γ is a positive regulator of endogenous oligodendrocyte precursor cell differentiation and remyelination and might be a pharmacological target for regenerative therapy in the CNS

Zn(II) Complexes of Glutathione Disulfide: Structural Basis of Elevated Stabilities

Glutathione disulfide (GSSG), a long disregarded redox partner of glutathione (GSH), is thought to participate in intracellular zinc homeostasis. We performed a concerted potentiometric and NMR spectroscopic study of protonation and Zn(II) binding properties of GSSG ((γECG)2) and a series of its nine analogs with C-terminal modifications, tripeptide disulfides: (γECS)2, (γECE)2, (γECG-NH2)2, (γECG-OEt)2, and (γEcG)2; dipeptide disulfides, (γEC)2and (γEC-OEt)2; and mixed disulfides, γECG-γEC and ECG-γEC-OEt. The acid-base and Zn(II) complexation properties in this group of compounds are strictly correlated to average C-terminal electrostatic charges. In particular, it was demonstrated that GSSG assumes a bent (head-to-tail) conformation in solution at neutral pH, which is controlled by electrostatic attraction between the protonated γ-amino groups of the Glu residue and the deprotonated C-terminal Gly carboxylates. This interaction modulates the ability of GSSG to coordinate Zn(II), both indirectly, by affecting the basicities of the amino groups, and directly, through the participation of the Gly carboxylates in the outer coordination sphere of the Zn(II) ion. A specific coiled structure of the major [Zn-GSSG]2- complex is additionally stabilized by the formation of hydrogen bonds between glycinyl carboxylates and two Zn(II)-coordinated water molecules. The elevated stability of Zn(II)-GSSG complexes was demonstrated by competition with FluoZin-3, a fluorescent sensor with high Zn(II) affinity, commonly used in in vitro and in vivo studies. The potential biological functions and reactivity of GSSG complexes of Zn(II) ions are discussed

Role of retinoic acid signaling in the development and functions of the nigrostriatal dopaminergic system

L'acide rétinoïque (AR), la forme active de la vitamine A, est une molécule essentielle au cours du développement et dans le cerveau adulte. La signalisation par l AR implique deux familles de récepteurs nucléaires: les récepteurs de l AR (Rar a, b et g) et les récepteurs des "rexinoïdes" (Rxr a, b et g) et les enzymes de la famille rétinaldéhyde déshydrogénases, les Raldhs (Raldh1, 2, 3). Rarb et/ou Raldh1 montrent des profils d'expression spatio-temporelle spécifiques dans le striatum et la substance noire pars compacta (SNc), les structures appartenant au système dopaminergique nigro-striée, ce qui suggère que l AR pourrait jouer un rôle important dans le développement et les fonctions post-natales du ce système. Dans ce travail, je montre que l ablation de Rarb conduit à un déficit de la neurogenèse de neurones épineux moyens (MSN) GABAergiques dans le striatum. Le nombre de neurones exprimant les récepteurs dopaminergiques D1 et D2, qui définissent les populations distinctes des MSN, sont réduit chez les souris Rarb-/-. Ces déficits cellulaires conduisent à la signalisation dopaminergique perturbée et une coordination motrice réduite chez les souris Rarb-/-. L ablation de Raldhl, l enzyme de synthèse de l AR présent dans le striatum postnatal, conduit à des déficits cellulaires et comportementaux similaires aux souris Rarb-/-. Ces résultats montrent que l AR produit en conditions physiologiques par Raldh1 est essentiel au maintien des MSN. Enfin, j'ai trouvé que l ablation de Raldh1, qui est également connu comme le marqueur spécifique le plus précoce des neurones dopaminergiques dans le mésencéphale embryonnaire, conduit à des anomalies du développement dans le SNc.Retinoic acid (RA), the bioactive derivatives of vitamin A, is well known for its critical role in development and homeostasis of the nervous system. RA signaling depends on activities of RA-producing enzymes, such as retinaldehyde dehydrogenases (Raldh1, 2, and 3) and two classes of retinoid receptors: retinoic acid receptors (Rar a, b, g) and retinoid X receptors (Rxr a, b, g). Rarb and/or Raldh1 show specific expression profile in the pre- and postnatal striatum and the substantia nigra pars compacta (SNc), the component structures of the nigrostriatal dopaminergic system, suggesting an essential role of RA during their development and homeostasis. Obtained results show that Rarb ablation affects development of discrete sub-population of medium spiny GABAergic neurons (MSN) during neurogenesis of the striatum resulting in its disturbed cytoarchitecture after birth. The number of dopamine D1 and D2 receptor positive neurons, which define neuroanatomically and molecularly distinct populations of MSNs are reduced in Rarb-/- mice. The cellular deficits result in compromised activities of dopamine receptor specific ligands and behavioral abnormalities consistent with striatal dysfunction. Moreover, similar cellular and behavioral deficits are found in the mice with null mutation in Raldh1 (Raldh1-/-), the major RA provider to the adult striatum, suggesting specific role of RA in the postnatal physiology of the structure. Finally, I found that compromised RA signaling by ablation of Raldh1, which is also known as the earliest specific marker of developing midbrain dopaminergic neurons, leads to impaired development of the SNc.STRASBOURG-Bib.electronique 063 (674829902) / SudocSudocFranceF

Dopamine D2 receptor controls hilar mossy cells excitability

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