Loss-of-function mutations in the CABLES1 gene are a novel cause of Cushing's disease.

The CABLES1 cell cycle regulator participates in the adrenal-pituitary negative feedback, and its expression is reduced in corticotropinomas, pituitary tumors with a largely unexplained genetic basis. We investigated the presence of CABLES1 mutations/copy number variations (CNVs) and their associated clinical, histopathological and molecular features in patients with Cushing's disease (CD). Samples from 146 pediatric (118 germline DNA only/28 germline and tumor DNA) and 35 adult (tumor DNA) CD patients were screened for CABLES1 mutations. CNVs were assessed in 116 pediatric CD patients (87 germline DNA only/29 germline and tumor DNA). Four potentially pathogenic missense variants in CABLES1 were identified, two in young adults (c.532G > A, p.E178K and c.718C > T, p.L240F) and two in children (c.935G > A, p.G312D and c.1388A > G, and p.D463G) with CD; no CNVs were found. The four variants affected residues within or close to the predicted cyclin-dependent kinase-3 (CDK3)-binding region of the CABLES1 protein and impaired its ability to block cell growth in a mouse corticotropinoma cell line (AtT20/D16v-F2). The four patients had macroadenomas. We provide evidence for a role of CABLES1 as a novel pituitary tumor-predisposing gene. Its function might link two of the main molecular mechanisms altered in corticotropinomas: the cyclin-dependent kinase/cyclin group of cell cycle regulators and the epidermal growth factor receptor signaling pathway. Further studies are needed to assess the prevalence of CABLES1 mutations among patients with other types of pituitary adenomas and to elucidate the pituitary-specific functions of this gene

Grain in a Plasma in the Presence of External Electric Field: Kinetic Calculation of Effective Potential and Ionic Drag Force

Kinetic calculations of the effective grain potential are presented for the case of weakly-ionized plasma in the external electric field. The drag force associated with the ionic drift in the external field is found. It is shown that the absorption of electrons and ions by the grain can cause the change of the direction of the drag force.Представлено кiнетичнi розрахунки ефективного потенцiалу порошинки для випадку слабоiонiзованої плазми у зовнiшньому електричному полi. Знайдено силу опору, яка пов’язана з дрейфом iонiв у зовнiшньому полi. Показано, що поглинання електронiв та iонiв порошинкою може привести до змiни напрямку сили опору

Multiple signaling pathways elicit circadian gene expression in cultured Rat-1 fibroblasts

In mammals, all overt circadian rhythms are thought to be coordinated by a central pacemaker residing in the hypothalamic suprachiasmatic nucleus (SCN) [1]. The phase of this pacemaker is entrained by photic cues via the retino-hypothalamic tract. Circadian clocks probably rely on a feedback loop in the expression of certain clock genes (reviewed in [2], [3]). Surprisingly, however, such molecular oscillators are not only operative in pacemaker cells, such as SCN neurons, but also in many peripheral tissues and even in cell lines kept in vitro[4], [5], [6], [7]. For example, a serum shock can induce circadian gene expression in cultured Rat-1 fibroblasts [5]. This treatment also results in a rapid surge of expression of the clock genes Per1 and Per2, similar to that observed in the SCNs of animals receiving a light pulse [8], [9], [10]. Serum induction of Per1 and Per2 transcription does not require ongoing protein synthesis [5] and must therefore be accomplished by direct signaling pathways. Here, we show that cAMP, protein kinase C, glucocorticoid hormones and Ca2+ can all trigger a transient surge of Per1 transcription and elicit rhythmic gene expression in Rat-1 cells. We thus suspect that the SCN pacemaker may exploit multiple chemical cues to synchronize peripheral oscillators in vivo

Control of mouse limb initiation and antero-posterior patterning by Meis transcription factors.

Meis1 and Meis2 are homeodomain transcription factors that regulate organogenesis through cooperation with Hox proteins. Elimination of Meis genes after limb induction has shown their role in limb proximo-distal patterning; however, limb development in the complete absence of Meis function has not been studied. Here, we report that Meis1/2 inactivation in the lateral plate mesoderm of mouse embryos leads to limb agenesis. Meis and Tbx factors converge in this function, extensively co-binding with Tbx to genomic sites and co-regulating enhancers of Fgf10, a critical factor in limb initiation. Limbs with three deleted Meis alleles show proximal-specific skeletal hypoplasia and agenesis of posterior skeletal elements. This failure in posterior specification results from an early role of Meis factors in establishing the limb antero-posterior prepattern required for Shh activation. Our results demonstrate roles for Meis transcription factors in early limb development and identify their involvement in previously undescribed interaction networks that regulate organogenesis.We thank members of the Torres group for stimulating discussions and suggestions. RNA probes were kindly provided by Marian Ros, Paola Bovolenta, and Jose Luis de la Pompa. We thank Keith Humphries and Hesham Sadek for providing the Meis1 floxed mice and Susan Mackem for the Hoxa6CreERT2 mice. We thank Alberto Benguría from the Genomics Unit, Manuel José Gómez from the Bioinformatics Unit, and Angeles Sanguino from the Pluripotent Cells Technology Unit. This study was supported by grant PGC2018-096486-B-I00 from the Spanish Ministerio de Ciencia e Innovación. The CNIC is supported by the Ministerio de Ciencia e Innovación and the Pro CNIC Foundation.S

Resetting of Circadian Time in Peripheral Tissues by Glucocorticoid Signaling

In mammals, circadian oscillators reside not only in the suprachiasmatic nucleus of the brain, which harbors the central pacemaker, but also in most peripheral tissues. Here, we show that the glucocorticoid hormone analog dexamethasone induces circadian gene expression in cultured rat-1 fibroblasts and transiently changes the phase of circadian gene expression in liver, kidney, and heart. However, dexamethasone does not affect cyclic gene expression in neurons of the suprachiasmatic nucleus. This enabled us to establish an apparent phase-shift response curve specifically for peripheral clocks in intact animals. In contrast to the central clock, circadian oscillators in peripheral tissues appear to remain responsive to phase resetting throughout the day

THe Cables1 Gene in Glucocorticoid Regulation of Pituitary Corticotrope Growth and Cushing Disease

International audienceContext: Cushing disease (CD) is due to pituitary corticotrope adenomas that produce unrestrained ACTH secretion and have lost the negative feedback exerted by glucocorticoids (GCs). GCs also restrain corticotrope proliferation, and the mechanisms of this inhibition are poorly understood. Objective: The aim of the study was to identify cell cycle regulatory genes that are regulated by GCs and the glucocorticoid receptor and to assess regulatory genes that have a rate-limiting action on corticotrope proliferation and may be disregulated in CD.Design: The mouse corticotrope tumor cells AtT-20 were used to identify GC-regulated genes that contribute to control of cell cycle progression. Surgery sections from patients with CD were used to assess expression of CABLES1 in corticotrope adenomas.Methods: Gene expression profiling, small interfering RNA knockdowns, cell cycle analyses, and genetic manipulations were performed in AtT-20 cells. Sequencing of chromatin immunoprecipitation for pituitary-restricted transcription factors and RNA polymerase II were used to identify regulatory elements and genes that bind GR and are direct transcriptional targets. A panel of previously well-characterized corticotrope adenomas was used to correlate expression of CABLES1 with that of other markers.Results: GCs altered expression of 3 positive and 3 negative regulators of cell cycle progression. Two Myc genes (L-Myc and N-Myc) and E2F2 are repressed by GCs, whereas genes for the negative regulators of the cell cycle, Gadd45, Gadd45, and Cables1 are activated by GCs. Cables1 small interfering RNA knockdown strongly stimulates AtT-20 cell proliferation and antagonizes the growth inhibition produced by GCs. The Gadd45 and Cables1 genes have the hallmarks of direct GC targets. CABLES1 is expressed in normal human pituitary cells, but expression is lost in 55% of corticotrope adenomas, and this is strongly correlated with the loss of p27 Kip1 expression.Conclusions: CABLES1 is a critical regulator of corticotrope proliferation that defines a pathway often inactivated in CD and links proliferation to GC resistance. (J Clin Endocrinol Meta

Mutations in NFKB2 and potential genetic heterogeneity in patients with DAVID syndrome, having variable endocrine and immune deficiencies.

International audienceDAVID syndrome is a rare condition combining anterior pituitary hormone deficiency with common variable immunodeficiency. NFKB2 mutations have recently been identified in patients with ACTH and variable immunodeficiency. A similar mutation was previously found in Nfkb2 in the immunodeficient Lym1 mouse strain, but the effect of the mutation on endocrine function was not evaluated. We ascertained six unrelated DAVID syndrome families. We performed whole exome and traditional Sanger sequencing to search for causal genes. Lym1 mice were examined for endocrine developmental anomalies. Mutations in the NFKB2 gene were identified in three of our families through whole exome sequencing, and in a fourth by direct Sanger sequencing. De novo origin of the mutations could be demonstrated in three of the families. All mutations lie near the C-terminus of the protein-coding region, near signals required for processing of NFΚB2 protein by the alternative pathway. Two of the probands had anatomical pituitary anomalies, and one had growth and thyroid hormone as well as ACTH deficiency; these findings have not been previously reported. Two children of one of the probands carried the mutation and have to date exhibited only an immune phenotype. No mutations were found near the C-terminus of NFKB2 in the remaining two probands; whole exome sequencing has been performed for one of these. Lym1 mice, carrying a similar Nfkb2 C-terminal mutation, showed normal pituitary anatomy and expression of proopiomelanocortin (POMC). We confirm previous findings that mutations near the C-terminus of NFKB2 cause combined endocrine and immunodeficiencies. De novo status of the mutations was confirmed in all cases for which both parents were available. The mutations are consistent with a dominant gain-of-function effect, generating an unprocessed NFKB2 super-repressor protein. We expand the potential phenotype of such NFKB2 mutations to include additional pituitary hormone deficiencies as well as anatomical pituitary anomalies. The lack of an observable endocrine phenotype in Lym1 mice suggests that the endocrine component of DAVID syndrome is either not due to a direct role of NFKB pathways on pituitary development, or else that human and mouse pituitary development differ in its requirements for NFKB pathway function