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El pdf del artículo es la versión de autor. ; Thyroid hormone influences brain maturation through interaction with nuclear receptors and regulation of gene expression. Their role on astrocyte maturation remains unclear. We have analyzed the role of thyroid hormone in rat cerebellar astrocyte maturation by comparing the sequential patterns of intermediate filament expression in normal and hypothyroid animals. During normal development astroglial cells sequentially express nestin, vimentin, and glial fibrillary acidic protein. Differentiated astrocytes appeared in the superior medullary vellum by postnatal day 2 and reached the white mater and internal granular layer by postnatal day 4. Intermediate filament marker expression was transiently lost from postnatal days 6 to 8 in anterior lobes, without an increased apoptosis. Vimentin expression was replaced by glial fibrillary acidic protein between postnatal days 10 and 32. The differentiated astrocytes were evenly distributed throughout the cerebellar slices, including the internal granular layer. Differences between normal and hypothyroid rats were observed starting from postnatal day 4, with lack of differentiated astrocytes in the internal granular layer. The transient decrease of astrocyte markers immunoreactivity in the anterior lobe did not take place in hypothyroid rats. The vimentin-glial fibrillary acidic protein transition was delayed and most differentiated astrocytes remained confined to the white matter. The results indicate that thyroid hormone deficiency induces a delay and a partial arrest of astrocyte differentiation. Astrocytes express thyroid hormone receptor α and β subtypes suggesting that astrocytes are direct target cells of thyroid hormones. © 2007 ISDN. ; This work was supported by grants from Ministry of Science and Technology BFU2005-01740 and the European Union Integrated Project CRESCENDO (LSHM-CT-2005-018652). ; Peer Reviewed

7 páginas, 4 figuras.-- et al. ; Thyroid hormones influence brain development through the control of gene expression. The concentration of the active hormone T-3 in the brain depends on T-3 transport through the blood-brain barrier, mediated in part by the monocarboxylate transporter 8 (Mct8/MCT8) and the activity of type 2 deiodinase (D2) generating T-3 from T-4. The relative roles of each of these pathways in the regulation of brain gene expression is not known. To shed light on this question, we analyzed thyroid hormone-dependent gene expression in the cerebral cortex of mice with inactivated Mct8 (Slc16a2) and Dio2 genes, alone or in combination. We used 34 target genes identified to be controlled by thyroidhormone in microarray comparisons of cerebral cortex from wild-type control and hypothyroid mice on postnatal d 21. Inactivation of the Mct8 gene (Mct8KO) was without effect on the expression of 31 of these genes. Normal gene expression in the absence of the transporter was mostly due to D2 activity because the combined disruption of Mct8 and Dio2 led to similar effects as hypothyroidism on the expression of 24 genes. Dio2 disruption alone did not affect the expression of positively regulated genes, but, as in hypothyroidism, it increased that of negatively regulated genes. We conclude that gene expression in the Mct8KO cerebral cortex is compensated in part by D2-dependent mechanisms. Intriguingly, positive or negative regulation of genes by thyroid hormone is sensitive to the source of T3 because Dio2 inactivation selectively affects the expression of negatively regulated genes. ; This work was supported by the Center for Biomedical Research on Rare Diseases; Grants SAF2008-01168 and SAF2008-00429E from the Ministry of Science and Innovation, Spain; the European Union Integrated Project CRESCENDO (LSHM-CT-2005-018652) Grants DK15070, DK07011, and DK20595 from the National Institutes of Health; and the Sherman family. A.C. is the holder of a predoctoral fellowship from the Ministry of Science and Innovation of Spain. ; Peer reviewed

6 pages, 6 figures. ; Thyroid hormones have important actions in the developing central nervous system. We describe here a novel action of thyroid hormone and its nuclear receptors on maturation of cerebellar gamma-aminobutyric acid (GABA)-ergic interneurons from their precursor cells. In rats, the density of GABAergic terminals in the cerebellum was decreased by hypothyroidism, as shown by immunohistochemistry for the GABA transporter GAT-1. This was due, at least partially, to a decreased number of GABAergic cells, because the number of Golgi II cells in the internal granular layer was decreased. GABAergic interneurons in the cerebellum differentiate from precursors expressing the Pax-2 transcription factor, generated in the subventricular zone of the embryonic fourth ventricle from where they migrate to the cerebellum. Hypothyroidism caused both decreased proliferation and delayed differentiation of precursors, with the net effect being an accumulation of immature cells during the neonatal period. The contribution of thyroid hormone receptors was studied by treating hypothyroid rats with T(3) or with the thyroid hormone receptor (TR) beta-selective agonist GC-1. Whereas treatment with T(3) reduced the number of precursors to control levels, GC-1 had only a partial effect, indicating that both TRalpha1 and TRbeta mediate the actions of T(3). Deletion of TRalpha1 in mice decreased cerebellar GAT-1 expression and Pax-2 precursor cell proliferation. It is concluded that thyroid hormone, acting through the nuclear receptors, has a major role in the proliferation and further differentiation of the Pax-2 precursors of cerebellar GABAergic cells. ; This work was supported by Grants BFU2005-01740 from the Ministry of Education and Science and the European Union Integrated Project CRESCENDO (LSHM-CT-2005-018652). ; Peer reviewed

Thyroid hormones regulate brain development and function through the control of gene expression, mediated by binding of T 3 to nuclear receptors. Brain T 3 concentration is tightly controlled by homeostatic mechanisms regulating transport and metabolism of T 4 and T 3. We have examined the role of the inactivating enzyme type 3 deiodinase (D3) in the regulation of 43 thyroid hormone-dependent genes in the cerebral cortex of 30-d-old mice. D3 inactivation increased slightly the expression of two of 22 positively regulated genes and significantly decreased the expression of seven of 21 negatively regulated genes. Administration of high doses of T 3 led to significant changes in the expression of 12 positive genes and three negative genes in wild-type mice. The response to T 3 treatment was enhanced in D3-deficient mice, both in the number of genes and in the amplitude of the response, demonstrating the role of D3 in modulating T 3 action. Comparison of the effects on gene expression observed in D3 deficiency with those in hypothyroidism, hyperthyroidism, and type 2 deiodinase (D2) deficiency revealed that the negative genes are more sensitive to D2 and D3 deficiencies than the positive genes. This observation indicates that, in normal physiological conditions, D2 and D3 play critical roles in maintaining local T 3 concentrations within a very narrow range. It also suggests that negatively and positively regulated genes do not have the same physiological significance or that their regulation by thyroid hormone obeys different paradigms at the molecular or cellular levels. Copyright © 2012 by The Endocrine Society. ; This work was supported by Grants SAF2008-01168 and SAF2008-00429-E from the Ministry of Education and Science of Spain, Grant LSHM-CT-2005-018652 from the European Union Integrated ProjectCRESCENDO,a grant from the Center for Biomedical Research on Rare Diseases, an initiative of the Instituto de Salud Carlos III, and by Grant NIMH-083220 from the National Institute of Mental Health. A.C. was recipient of a predoctoral fellowship from the Plan Nacional de I+D+i. ; Peer Reviewed

Thyroid hormone analogs with selective actions through specific thyroid hormone receptor (TR) subtypes are of great interest. They might offer the possibility of mimicking physiological actions of thyroid hormone with receptor subtype or tissue specificity with therapeutic aims. They are also pharmacological tools to dissect biochemical pathways mediated by specific receptor subtypes, in a complementary way to mouse genetic modifications. In this work, we studied the in vivo activity in developing rats of two thyroid hormone agonists, the TR beta-selective GC-24 and the TR beta-selective CO23. Our principal goal was to check whether these compounds were active in the rat brain. Analog activity was assessed by measuring the expression of thyroid hormone target genes in liver, heart, and brain, after administration to hypothyroid rats. GC-24 was very selective for TR beta and lacked activity on the brain. On the other hand, CO23 was active in liver, heart, and brain on genes regulated by either TR alpha or TR beta. This compound, previously shown to be TR alpha-selective in tadpoles, displayed no selectivity in the rat in vivo. ; This work was supported by Ministry of Science of Spain Grants SAF2008-01168 and SAF2008-00429E, the European Union Integrated Project "CRESCENDO", the Center for Biomedical Research on Rare Diseases, the Instituto de Salud Carlos III (J.B.), and the National Institutes of Health Grant DK-52798 (to T.S.S.). ; Peer reviewed

Mutations of the monocarboxylate transporter 8 gene (MCT8, SLC16A2) cause the Allan-Herndon-Dudley syndrome, an X-linked syndrome of severe intellectual deficit and neurological impairment. Mct8 transports thyroid hormones (T4 and T3), and the Allan-Herndon-Dudley syndrome is likely caused by lack of T3 transport to neurons during critical periods of fetal brain development. To evaluate the role of Mct8 in thyroid hormone action in the fetal brain we administered T4 or T3 to thyroidectomized pregnant dams treated with methyl-mercapto-imidazol to produce maternal and fetal hypothyroidism. Gene expression was then measured in the fetal cerebral cortex. T4 increased Camk4, Sema3c, and Slc7a3 expression, but T3 was without effect. To investigate the cause for the lack of T3 action we analyzed the expression of organic anion transport polypeptide (Oatp14, Slco1c1), a T4 transporter, and Mct8 (Slc16a2), a T4 and T3 transporter, by confocal microscopy. Both proteins were present in the brain capillaries forming the blood-brain barrier and in the epithelial cells of the choroid plexus forming the blood-cerebrospinal fluid barrier. It is concluded that T4 from the maternal compartment influences gene expression in the fetal cerebral cortex, possibly after transport via organic anion transporter polypeptide and/or Mct8, and conversion to T3 in the astrocytes. On the other hand, T3 does not reach the target neurons despite the presence of Mct8. The data indicate that T4, through local deiodination, provides most T3 in the fetal rat brain. The role of Mct8 as a T3 transporter in the fetal rat brain is therefore uncertain. Copyright © 2011 by The Endocrine Society. ; This work was supported by Grants SAF2008-01168 and SAF2008-00429E from the Ministry of Science and Innovation, Spain, the European Union Integrated Project CRESCENDO (LSHM-CT-2005-018652), and by the Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III. D.D. was supported by the I3P program of the Consejo Superior de Investigaciones Científicas, Spain and by a postdoctoral fellowship from The Japanese Society for the Promotion of Science. ; Peer Reviewed

11 p., 6 figures, 1 table and references. ; Thyroid hormones influence brain development through regulation of gene expression mediated by nuclear receptors. Nuclear receptor concentration increases rapidly in the human fetus during the secondtrimester,aperiod of high sensitivity of the brain to thyroidhormones.In the rat, the equivalent period is the last quarter of pregnancy. However, little is known about thyroid hormone action in the fetal brain, and in rodents, most thyroid hormone-regulated genes have been identified during the postnatal period. To identify potential targets of thyroid hormone in the fetal brain,weinduced maternal and fetal hypothyroidism by maternal thyroidectomy followed by antithyroid drug (2-mercapto-1-methylimidazole) treatment. Microarray analysis identified differentially expressed genes in the cerebral cortex of hypothyroid fetuses on d 21 after conception. Gene function analysis revealed genes involved in the biogenesis of the cytoskeleton, neuronal migration and growth,and branching of neurites. Twenty percent of the differentially expressed genes were related to each other centered on the Ca2 and calmodulin-activated kinase (Camk4) pathway.Camk4was regulated directly by T3 in primary cultured neurons from fetal cortex, and the Camk4 protein was also induced by thyroid hormone. No differentially expressed genes were recovered when euthyroid fetuses from hypothyroid mothers were compared with fetuses from normal mothers. Although the resultsdonot rule out a specific contribution from the mother, especially at earlier stages of pregnancy, they indicate that the main regulators of thyroid hormone-dependent, fetal brain gene expression near term are the fetal thyroid hormones. ; This work was supported by Grants BFU2005-01740, SAF2008-01168, and SAF2006-14068 from the Ministry of Science and Innovation, Spain, by the European Union Integrated Project CRESCENDO (LSHM- CT-2005-018652), and by the Center for Biomedical Research on Rare Diseases (CIBERER). D.D. was supported by the I3P program of the Consejo Superior de Investigaciones Científicas, Spain, and by a postdoctoral fellowship from The Japanese Society for the Promotion of Science. D.N. was supported by a predoctoral fellowship of the Spanish Ministry of Science and Innovation. ; Peer reviewed

The knowledge of the genetic variability of the local population is of utmost importance in personalized medicine and has been revealed as a critical factor for the discovery of new disease variants. Here, we present the Collaborative Spanish Variability Server (CSVS), which currently contains more than 2000 genomes and exomes of unrelated Spanish individuals. This database has been generated in a collaborative crowdsourcing effort collecting sequencing data produced by local genomic projects and for other purposes. Sequences have been grouped by ICD10 upper categories. A web interface allows querying the database removing one or more ICD10 categories. In this way, aggregated counts of allele frequencies of the pseudo-control Spanish population can be obtained for diseases belonging to the category removed. Interestingly, in addition to pseudo-control studies, some population studies can be made, as, for example, prevalence of pharmacogenomic variants, etc. In addition, this genomic data has been used to define the first Spanish Genome Reference Panel (SGRP1.0) for imputation. This is the first local repository of variability entirely produced by a crowdsourcing effort and constitutes an example for future initiatives to characterize local variability worldwide. CSVS is also part of the GA4GH Beacon network. CSVS can be accessed at: http://csvs.babelomics.org/. ; Spanish Ministry of Economy and Competitiveness [SAF2017-88908-R, PT17/0009/0006 to J.D.; PI19/00321 and CIBERER ACCI-06/07/0036 to C.A., PI14-948, PI171659 and CIBERER ACCI-06/07/0036 to M.A.M.P.]; Regional Government of Madrid, RAREGenomicsCM [B2017/BMD-3721 to C.A. and B2017/BMD3721 to M.A.M.P.]; all co-funded with European Regional Development Funds (ERDF) as well as EU H2020INFRADEV-1-2015-1 ELIXIR-EXCELERATE [676559]; University Chair UAM-IIS-FJD of Genomic Medicine and the Ramon Areces Foundation also supported this work. Funding for open access charge: Spanish Ministry of Economy and Competitiveness [SAF2017-88908-R]. ; Sí

The knowledge of the genetic variability of the local population is of utmost importance in personalized medicine and has been revealed as a critical factor for the discovery of new disease variants. Here, we present the Collaborative Spanish Variability Server (CSVS), which currently contains more than 2000 genomes and exomes of unrelated Spanish individuals. This database has been generated in a collaborative crowdsourcing effort collecting sequencing data produced by local genomic projects and for other purposes. Sequences have been grouped by ICD10 upper categories. A web interface allows querying the database removing one or more ICD10 categories. In this way, aggregated counts of allele frequencies of the pseudo-control Spanish population can be obtained for diseases belonging to the category removed. Interestingly, in addition to pseudo-control studies, some population studies can be made, as, for example, prevalence of pharmacogenomic variants, etc. In addition, this genomic data has been used to define the first Spanish Genome Reference Panel (SGRP1.0) for imputation. This is the first local repository of variability entirely produced by a crowdsourcing effort and constitutes an example for future initiatives to characterize local variability worldwide. CSVS is also part of the GA4GH Beacon network. CSVS can be accessed at: http://csvs.babelomics.org/. ; Spanish Ministry of Economy and Competitiveness [SAF2017-88908-R, PT17/0009/0006 to J.D.; PI19/00321 and CIBERER ACCI-06/07/0036 to C.A., PI14-948, PI17-1659 and CIBERER ACCI-06/07/0036 to M.A.M.P.]; Regional Government of Madrid, RAREGenomics-CM [B2017/BMD-3721 to C.A. and B2017/BMD3721 to M.A.M.P.]; all co-funded with European Regional Development Funds (ERDF) as well as EU H2020-INFRADEV-1-2015-1 ELIXIR-EXCELERATE [676559]; University Chair UAM-IIS-FJD of Genomic Medicine and the Ramon Areces Foundation also supported this work. Funding for open access charge: Spanish Ministry of Economy and Competitiveness [SAF2017-88908-R]. ; Peer reviewed