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1.
Endocrinology ; 165(4)2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38325289

RESUMEN

The mineralocorticoid receptor (MR) is a transcription factor for genes mediating diverse, cell-specific functions, including trophic effects as well as promoting fluid/electrolyte homeostasis. It was reported that in intercalated cells, phosphorylation of the MR at serine 843 (S843) by Unc-51-like kinase (ULK1) inhibits MR activation and that phosphorylation of ULK1 by mechanistic target of rapamycin (mTOR) inactivates ULK1, and thereby prevents MR inactivation. We extended these findings with studies in M1 mouse cortical collecting duct cells stably expressing the rat MR and a reporter gene. Pharmacological inhibition of ULK1 dose-dependently increased ligand-induced MR transactivation, while ULK1 activation had no effect. Pharmacological inhibition of mTOR and CRISPR/gRNA gene knockdown of rapamycin-sensitive adapter protein of mTOR (Raptor) or rapamycin-insensitive companion of mTOR (Rictor) decreased phosphorylated ULK1 and ligand-induced activation of the MR reporter gene, as well as transcription of endogenous MR-target genes. As predicted, ULK1 inhibition had no effect on aldosterone-mediated transcription in M1 cells with the mutated MR-S843A (alanine cannot be phosphorylated). In contrast, mTOR inhibition dose-dependently decreased transcription in the MR-S843A cells, though not as completely as in cells with the wild-type MR-S843. mTOR, Raptor, and Rictor coprecipitated with the MR and addition of aldosterone increased their phosphorylated, active state. These results suggest that mTOR significantly regulates MR activity in at least 2 ways: by suppressing MR inactivation by ULK1, and by a yet ill-defined mechanism that involves direct association with MR. They also provide new insights into the diverse functions of ULK1 and mTOR, 2 key enzymes that monitor the cell's energy status.


Asunto(s)
Aldosterona , Receptores de Mineralocorticoides , Animales , Ratones , Ratas , Homólogo de la Proteína 1 Relacionada con la Autofagia/genética , Homólogo de la Proteína 1 Relacionada con la Autofagia/metabolismo , Ligandos , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Complejos Multiproteicos/metabolismo , Fosforilación , Proteína Asociada al mTOR Insensible a la Rapamicina/metabolismo , Receptores de Mineralocorticoides/genética , Receptores de Mineralocorticoides/metabolismo , Proteína Reguladora Asociada a mTOR , ARN Guía de Sistemas CRISPR-Cas , Sirolimus/farmacología , Serina-Treonina Quinasas TOR/metabolismo , Factores de Transcripción/metabolismo
2.
Endocrine ; 2024 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-38353885

RESUMEN

Cowden syndrome (CS) is a rare genetic condition due to the various germline mutations in the phosphatase and tensin homologue on chromosome ten (PTEN) tumour suppressor gene. As a result, CS is characterised by an increased risk of developing various benign and malignant tumours, such as thyroid, breast, endometrial and urogenital neoplasms, as well as gastrointestinal tract tumours. However, the neuroendocrine tumour association with CS is not elucidated yet. We present a case of a 46-year-old male patient diagnosed with testicular seminoma and follicular thyroid cancer in his medical history. Our patient met the clinical diagnostic criteria of Cowden syndrome. Genetic analysis established the clinical diagnosis; a known heterozygous PTEN mutation was detected [PTEN (LRG_311t1)c.388 C > T (p.Arg130Ter)]. Incidentally, he was also seen with multiple pulmonary lesions during his oncological follow-up. A video-assisted thoracoscopic left lingula wedge resection and later resections from the right lung were performed. Histological findings revealed typical pulmonary carcinoid tumours and smaller tumorlets. Somatostatin receptor SPECT-CT, 18F-FDG-PET-CT and 18F-FDOPA-PET-CT scans and endoscopy procedures could not identify any primary tumours in other locations. Our patient is the first published case of Cowden syndrome, associated with multifocal pulmonary carcinoids. Besides multiple endocrine neoplasia type 1, we propose Cowden syndrome as another hereditary condition predisposing to multiple pulmonary tumorlets and carcinoid tumours.

3.
J Med Genet ; 59(9): 916-919, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34916233

RESUMEN

Gorlin-Goltz syndrome (GGS) or nevoid basal cell carcinoma syndrome is a rare tumour-overgrowth syndrome associated with multiple developmental anomalies and a wide variety of tumours. Here, we describe a case of a man aged 23 years with GGS with bilateral giant tumours adjacent to both adrenals that raised the suspicion of malignancy on imaging. Histological analysis of both surgically resected tumours revealed perivascular epitheloid cell tumours (PEComas) that were independent of the adrenals. Exome sequencing of the patient's blood sample revealed a novel germline heterozygous frameshift mutation in the PTCH1 gene. As a second hit, a somatic five nucleotide long deletion in the PTCH1 gene was demonstrated in the tumour DNA of both PEComas. To the best of our knowledge, this is the first report on PEComa in GGS, and this finding also raises the potential relevance of PTCH1 mutations and altered sonic hedgehog signalling in PEComa pathogenesis. The presence of the same somatic mutation in the bilateral tumours might indicate the possibility of a postzygotic somatic mutation that along with the germline mutation of the same gene could represent an intriguing genetic phenomenon (type 2 segmental mosaicism).


Asunto(s)
Síndrome del Nevo Basocelular , Receptor Patched-1 , Neoplasias de Células Epitelioides Perivasculares , Síndrome del Nevo Basocelular/genética , Síndrome del Nevo Basocelular/patología , Proteínas Hedgehog/genética , Humanos , Masculino , Mosaicismo , Mutación , Receptor Patched-1/genética , Adulto Joven
4.
Cell Rep ; 37(1): 109785, 2021 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-34610303

RESUMEN

A hallmark of type 2 diabetes (T2D) is hepatic resistance to insulin's glucose-lowering effects. The serum- and glucocorticoid-regulated family of protein kinases (SGK) is activated downstream of mechanistic target of rapamycin complex 2 (mTORC2) in response to insulin in parallel to AKT. Surprisingly, despite an identical substrate recognition motif to AKT, which drives insulin sensitivity, pathological accumulation of SGK1 drives insulin resistance. Liver-specific Sgk1-knockout (Sgk1Lko) mice display improved glucose tolerance and insulin sensitivity and are protected from hepatic steatosis when fed a high-fat diet. Sgk1 promotes insulin resistance by inactivating AMP-activated protein kinase (AMPK) via phosphorylation on inhibitory site AMPKαSer485/491. We demonstrate that SGK1 is dominant among SGK family kinases in regulation of insulin sensitivity, as Sgk1, Sgk2, and Sgk3 triple-knockout mice have similar increases in hepatic insulin sensitivity. In aggregate, these data suggest that targeting hepatic SGK1 may have therapeutic potential in T2D.


Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Proteínas Inmediatas-Precoces/metabolismo , Hígado/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Quinasas Activadas por AMP/antagonistas & inhibidores , Animales , Diabetes Mellitus Tipo 2/patología , Dieta Alta en Grasa , Proteína Forkhead Box O1/metabolismo , Glucosa/metabolismo , Proteínas Inmediatas-Precoces/deficiencia , Proteínas Inmediatas-Precoces/genética , Insulina/metabolismo , Resistencia a la Insulina , Diana Mecanicista del Complejo 2 de la Rapamicina/metabolismo , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fosforilación , Proteínas Serina-Treonina Quinasas/deficiencia , Proteínas Serina-Treonina Quinasas/genética , Proteínas Proto-Oncogénicas c-akt/metabolismo , ARN Guía de Kinetoplastida/metabolismo , Transducción de Señal
5.
BMC Endocr Disord ; 20(1): 183, 2020 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-33317492

RESUMEN

BACKGROUND: Thyroid associated orbitopathy (TAO) is the most common extrathyroidal complication of Graves' disease. The disease course ranges from mild, where symptomatic therapy is sufficient, to severe, where high dose steroid administration or orbital decompression surgery is required. Women of their reproductive age are more likely to be affected. Although pregnancy is a state of enhanced immune tolerance, TAO may develop or worsen in 0.2-0.4% of pregnant women. CASE PRESENTATION: We present the case of a 19-year-old woman who has developed hyperthyroidism and progressive TAO during the second trimester of her third pregnancy, which has improved postpartum. The possible mechanisms and the importance of follow up in pregnancy is discussed. CONCLUSIONS: Expectant mothers with Graves' disease require follow up of eye signs throughout pregnancy, preferably in the setting of a thyroid-eye clinic.


Asunto(s)
Oftalmopatía de Graves/sangre , Oftalmopatía de Graves/diagnóstico , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/diagnóstico , Femenino , Oftalmopatía de Graves/etiología , Humanos , Hipertiroidismo/sangre , Hipertiroidismo/diagnóstico , Hipertiroidismo/etiología , Recién Nacido , Embarazo , Hormonas Tiroideas/sangre , Adulto Joven
7.
Sci Rep ; 10(1): 14751, 2020 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-32901079

RESUMEN

Drugs of abuse cause significant neuroadaptations within the ventral tegmental area (VTA), with alterations in gene expression tied to changes in reward behavior. Serum- and glucocorticoid-inducible kinase 1 (SGK1) transcription, catalytic activity, and phosphorylation are upregulated in the VTA by chronic cocaine or morphine treatment, positioning SGK1 as a critical mediator of reward behavior. Using transgenic mouse models, we investigated the effect of SGK1 knockout in the VTA and in dopamine (DA) neurons to evaluate the necessity of protein expression for natural and drug reward behaviors. SGK1 knockdown in the VTA did not impact reward behaviors. Given VTA cellular heterogeneity, we also investigated a DA neuron-specific SGK1 knockout (KO). DA SGK1 KO significantly decreased body weight of adult mice as well as increased general locomotor activity; however, reward behaviors were similarly unaltered. Given that SGK1 mutants virally overexpressed in the VTA are capable of altering drug-associated behavior, our current results suggest that changes in SGK1 protein signaling may be distinct from expression. This work yields novel information on the impact of SGK1 deletion, critical for understanding the role of SGK1 signaling in the central nervous system and evaluating SGK1 as a potential therapeutic target for treatment of substance use disorders.


Asunto(s)
Conducta Animal/efectos de los fármacos , Cocaína/farmacología , Neuronas Dopaminérgicas/efectos de los fármacos , Proteínas Inmediatas-Precoces/fisiología , Proteínas Serina-Treonina Quinasas/fisiología , Recompensa , Área Tegmental Ventral/efectos de los fármacos , Animales , Inhibidores de Captación de Dopamina/farmacología , Neuronas Dopaminérgicas/patología , Femenino , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transducción de Señal , Área Tegmental Ventral/patología
8.
Neuropharmacology ; 179: 108286, 2020 11 15.
Artículo en Inglés | MEDLINE | ID: mdl-32841607

RESUMEN

Previously, we showed a differential regulation of the human delta-opioid receptor (hDOPr) by etorphine and [D-Pen2, D-Pen5] enkephalin (DPDPE). To understand the molecular basis of such differences, we introduced 3 alanine mutations at the residues T161. Y318 and S363. Both wild type (WT) and hDOPr mutants were expressed in HEK cells containing endogenous arrestins or CFP-tagged arrestin 3, then desensitization, internalization, recycling and phosphorylation were studied. In a context of endogenous arrestin expression, a major difference in DOPr desensitization was observed between agonists that was modified with the T161A mutation upon etorphine and with the S363A substitution upon DPDPE exposure. While both agonists induced a major receptor internalization, T161A and S363A impaired DOPr sequestration only for etorphine. However, similar level of S363 phosphorylation was measured between agonists. When CFP-tagged arrestin 3 was over-expressed, a similar profile of desensitization was measured for both agonists. In this context, all the 3 alanine mutations decreased etorphine-induced receptor desensitization. Using FRET, we showed similar interactions between WT hDOPr and arrestin 3 under DPDPE and etorphine stimulation which were delayed by both the Y318A and the S363A substitutions for etorphine. Finally, hDOPr recycling was qualitatively evaluated by microscopy and showed neither arrestin 3/hDOPr colocalization nor major impact of alanine mutations except for the S363A which impaired internalization and recycling for etorphine. The T161, Y318 and S363 residues of hDOPr could underlie the differential regulation promoted by DPDPE and etorphine.


Asunto(s)
Alanina/genética , Alcaloides/farmacología , Analgésicos Opioides/farmacología , Mutación/genética , Receptores Opioides delta/agonistas , Receptores Opioides delta/genética , Alcaloides/química , Analgésicos Opioides/química , Células HEK293 , Humanos , Unión Proteica/efectos de los fármacos , Unión Proteica/fisiología
9.
Phys Rev Lett ; 125(2): 020402, 2020 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-32701319

RESUMEN

We consider bipartite entangled states that cannot outperform separable states in any linear interferometer. Then, we show that these states can still be more useful metrologically than separable states if several copies of the state are provided or an ancilla is added to the quantum system. We present a general method to find the local Hamiltonian for which a given quantum state performs the best compared to separable states. We obtain analytically the optimal Hamiltonian for some quantum states with a high symmetry. We show that all bipartite entangled pure states outperform separable states in metrology. Some potential applications of the results are also suggested.

10.
Nat Commun ; 11(1): 2415, 2020 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-32415093

RESUMEN

Quantum technologies use entanglement to outperform classical technologies, and often employ strong cooling and isolation to protect entangled entities from decoherence by random interactions. Here we show that the opposite strategy-promoting random interactions-can help generate and preserve entanglement. We use optical quantum non-demolition measurement to produce entanglement in a hot alkali vapor, in a regime dominated by random spin-exchange collisions. We use Bayesian statistics and spin-squeezing inequalities to show that at least 1.52(4) × 1013 of the 5.32(12) × 1013 participating atoms enter into singlet-type entangled states, which persist for tens of spin-thermalization times and span thousands of times the nearest-neighbor distance. The results show that high temperatures and strong random interactions need not destroy many-body quantum coherence, that collective measurement can produce very complex entangled states, and that the hot, strongly-interacting media now in use for extreme atomic sensing are well suited for sensing beyond the standard quantum limit.

11.
Nanotechnology ; 30(40): 405501, 2019 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-31247600

RESUMEN

Transition metal dichalcogenides (TMDs) have received immense research interest in particular for their outstanding electrochemical and optoelectrical properties. Lately, chemical gas sensor applications of TMDs have been recognized as well owing to the low operating temperatures of devices, which is a great advantage over conventional metal oxide based sensors. In this work, we elaborate on the gas sensing properties of WS2 and MoS2 thin films made by simple and straightforward thermal sulfurization of sputter deposited metal films on silicon chips. The sensor response to H2, H2S, CO and NH3 analytes in air at 30 °C has been assessed and both MoS2 and WS2 were found to have an excellent selectivity to NH3 with a particularly high sensitivity of 0.10 ± 0.02 ppm-1 at sub-ppm concentrations in the case of WS2. The sensing behavior is explained on the bases of gas adsorption energies as well as carrier (hole) localization induced by the surface adsorbed moieties having reductive nature.

12.
Endocrine ; 65(2): 451-459, 2019 08.
Artículo en Inglés | MEDLINE | ID: mdl-31044390

RESUMEN

PURPOSE: Multiple endocrine neoplasia type 1 is a rare tumor syndrome caused by germline mutations of MEN1 gene. Phenotype varies widely, and no definitive correlation with the genotype has been observed. Mutation-negative patients with MEN1-associated tumors represent phenocopies. By comparing mutation-positive and mutation-negative patients, we aimed to identify phenotype features predictive for a positive genetic test and to evaluate the role of MEN1 mutations in phenotype modulation. METHODS: Mutation screeening of MEN1 gene by Sanger sequencing and assessment of clinical data of 189 consecutively enrolled probands and relatives were performed at our national and European Reference Center. Multiple ligation probe amplification analysis of MEN1 gene and Sanger sequencing of CDKN1B were carried out in clinically suspicious but MEN1-negative cases. RESULTS: Twenty-seven probands and twenty family members carried MEN1 mutations. Five mutations have not been described earlier. Pronouncedly high number of phenocopies (>70%) was observed. Clinical suspicion of MEN1 syndrome emerged at significantly earlier age in MEN1-positive compared to MEN1-negative probands. Gastroenteropancreatic neuroendocrine tumors developed significantly earlier and more frequently in carriers compared to non-carriers. Probands with high-impact (frameshift, nonsense, large deletions) mutations, predicted to affect menin function significantly, developed GEP-NETs more frequently compared to low-impact (inframe and missense) mutation carriers. CONCLUSIONS: MEN1 phenocopy is common and represents a significant confounder for the genetic testing. GEP-NET under 30 years best predicted a MEN1 mutation. The present study thus confirmed a previous proposal and suggested that GEP-NET under 30 years should be considered as a part of the indication criteria for MEN1 mutational analysis.


Asunto(s)
Neoplasia Endocrina Múltiple Tipo 1/genética , Proteínas Proto-Oncogénicas/genética , Adulto , Edad de Inicio , Anciano , Análisis Mutacional de ADN , Femenino , Estudios de Asociación Genética , Pruebas Genéticas , Humanos , Hungría/epidemiología , Incidencia , Masculino , Persona de Mediana Edad , Neoplasia Endocrina Múltiple Tipo 1/epidemiología , Mutación , Penetrancia , Estudios Retrospectivos
13.
Cell ; 177(2): 299-314.e16, 2019 04 04.
Artículo en Inglés | MEDLINE | ID: mdl-30929899

RESUMEN

Autophagy is required in diverse paradigms of lifespan extension, leading to the prevailing notion that autophagy is beneficial for longevity. However, why autophagy is harmful in certain contexts remains unexplained. Here, we show that mitochondrial permeability defines the impact of autophagy on aging. Elevated autophagy unexpectedly shortens lifespan in C. elegans lacking serum/glucocorticoid regulated kinase-1 (sgk-1) because of increased mitochondrial permeability. In sgk-1 mutants, reducing levels of autophagy or mitochondrial permeability transition pore (mPTP) opening restores normal lifespan. Remarkably, low mitochondrial permeability is required across all paradigms examined of autophagy-dependent lifespan extension. Genetically induced mPTP opening blocks autophagy-dependent lifespan extension resulting from caloric restriction or loss of germline stem cells. Mitochondrial permeability similarly transforms autophagy into a destructive force in mammals, as liver-specific Sgk knockout mice demonstrate marked enhancement of hepatocyte autophagy, mPTP opening, and death with ischemia/reperfusion injury. Targeting mitochondrial permeability may maximize benefits of autophagy in aging.


Asunto(s)
Envejecimiento/metabolismo , Proteínas de Transporte de Membrana Mitocondrial/fisiología , Membranas Mitocondriales/fisiología , Animales , Autofagia/fisiología , Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas de Caenorhabditis elegans/fisiología , Restricción Calórica , Células HEK293 , Humanos , Longevidad/fisiología , Masculino , Ratones , Ratones Noqueados , Mitocondrias , Proteínas de Transporte de Membrana Mitocondrial/metabolismo , Poro de Transición de la Permeabilidad Mitocondrial , Permeabilidad , Cultivo Primario de Células , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/fisiología , Daño por Reperfusión/metabolismo , Transducción de Señal
14.
J Cereb Blood Flow Metab ; 39(6): 1111-1121, 2019 06.
Artículo en Inglés | MEDLINE | ID: mdl-29260627

RESUMEN

Nitrones (e.g. α-phenyl-N-tert-butyl nitrone; PBN) are cerebroprotective in experimental stroke. Free radical trapping is their proposed mechanism. As PBN has low radical trapping potency, we tested Sgk1 induction as another possible mechanism. PBN was injected (100 mg/kg, i.p.) into adult male rats and mice. Sgk1 was quantified in cerebral tissue by microarray, quantitative RT-PCR and western analyses. Sgk1+/+ and Sgk1-/- mice were randomized to receive PBN or saline immediately following transient (60 min) occlusion of the middle cerebral artery. Neurological deficit was measured at 24 h and 48 h and infarct volume at 48 h post-occlusion. Following systemic PBN administration, rapid induction of Sgk1 was detected by microarray (at 4 h) and confirmed by RT-PCR and phosphorylation of the Sgk1-specific substrate NDRG1 (at 6 h). PBN-treated Sgk1+/+ mice had lower neurological deficit ( p < 0.01) and infarct volume ( p < 0.01) than saline-treated Sgk1+/+ mice. PBN-treated Sgk1-/- mice did not differ from saline-treated Sgk1-/- mice. Saline-treated Sgk1-/- and Sgk1+/+ mice did not differ. Brain Sgk3:Sgk1 mRNA ratio was 1.0:10.6 in Sgk1+/+ mice. Sgk3 was not augmented in Sgk1-/- mice. We conclude that acute systemic treatment with PBN induces Sgk1 in brain tissue. Sgk1 may play a part in PBN-dependent actions in acute brain ischemia.


Asunto(s)
Óxidos N-Cíclicos/uso terapéutico , Proteínas Inmediatas-Precoces/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/efectos de los fármacos , Animales , Encéfalo/metabolismo , Isquemia Encefálica/tratamiento farmacológico , Óxidos N-Cíclicos/farmacología , Proteínas Inmediatas-Precoces/genética , Proteínas Inmediatas-Precoces/farmacología , Infarto de la Arteria Cerebral Media/tratamiento farmacológico , Masculino , Ratones , Ratones Noqueados , Óxidos de Nitrógeno/farmacología , Óxidos de Nitrógeno/uso terapéutico , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/farmacología , Ratas , Accidente Cerebrovascular/tratamiento farmacológico , Activación Transcripcional/efectos de los fármacos
15.
Redox Biol ; 19: 46-51, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30107294

RESUMEN

Regular physical exercise has health benefits and can prevent some of the ageing-associated muscle deteriorations. However, the biochemical mechanisms underlying this exercise benefit, especially in human tissues, are not well known. To investigate, we assessed this using miRNA profiling, mRNA and protein levels of anti-oxidant and metabolic proteins in the vastus lateralis muscle of master athletes aged over 65 years and age-matched controls. Master athletes had lower levels of miR-7, while mRNA or protein levels of SIRT3, SIRT1, SOD2, and FOXO1 levels were significantly higher in the vastus lateralis muscle of master athletes compared to muscles of age-matched controls. These results suggest that regular exercise results in better cellular metabolism and antioxidant capacity via maintaining physiological state of mitochondria and efficient ATP production and decreasing ageing-related inflammation as indicated by the lower level of miR-7 in master athletes.


Asunto(s)
Ejercicio Físico , MicroARNs/genética , Músculo Esquelético/fisiología , Sirtuina 3/genética , Superóxido Dismutasa/genética , Regulación hacia Arriba , Anciano , Envejecimiento , Atletas , Regulación hacia Abajo , Femenino , Expresión Génica , Humanos , Masculino , Persona de Mediana Edad , ARN Mensajero/genética , Conducta Sedentaria , Transcriptoma
16.
Science ; 360(6387): 416-418, 2018 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-29700263

RESUMEN

Modern quantum technologies in the fields of quantum computing, quantum simulation, and quantum metrology require the creation and control of large ensembles of entangled particles. In ultracold ensembles of neutral atoms, nonclassical states have been generated with mutual entanglement among thousands of particles. The entanglement generation relies on the fundamental particle-exchange symmetry in ensembles of identical particles, which lacks the standard notion of entanglement between clearly definable subsystems. Here, we present the generation of entanglement between two spatially separated clouds by splitting an ensemble of ultracold identical particles prepared in a twin Fock state. Because the clouds can be addressed individually, our experiments open a path to exploit the available entangled states of indistinguishable particles for quantum information applications.

17.
J Phys Condens Matter ; 30(19): 195602, 2018 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-29578454

RESUMEN

We study quantum entanglement loss due to environmental interaction in a condensed matter system with a complex geometry relevant to recent proposals for computing with single electrons at the nanoscale. We consider a system consisting of two qubits, each realized by an electron in a double quantum dot, which are initially in an entangled Bell state. The qubits are widely separated and each interacts with its own environment. The environment for each is modeled by surrounding double quantum dots placed at random positions with random orientations. We calculate the unitary evolution of the joint system and environment. The global state remains pure throughout. We examine the time dependence of the expectation value of the bipartite Clauser-Horne-Shimony-Holt (CHSH) and Brukner-Paunkovic-Rudolph-Vedral (BPRV) Bell operators and explore the emergence of correlations consistent with local realism. Though the details of this transition depend on the specific environmental geometry, we show how the results can be mapped on to a universal behavior with appropriate scaling. We determine the relevant disentanglement times based on realistic physical parameters for molecular double-dots.

18.
Phys Rev Lett ; 120(2): 020506, 2018 Jan 12.
Artículo en Inglés | MEDLINE | ID: mdl-29376687

RESUMEN

We show that multipartite quantum states that have a positive partial transpose with respect to all bipartitions of the particles can outperform separable states in linear interferometers. We introduce a powerful iterative method to find such states. We present some examples for multipartite states and examine the scaling of the precision with the particle number. Some bipartite examples are also shown that possess an entanglement very robust to noise. We also discuss the relation of metrological usefulness to Bell inequality violation. We find that quantum states that do not violate any Bell inequality can outperform separable states metrologically. We present such states with a positive partial transpose, as well as with a nonpositive partial transpose.

19.
Diabetes ; 67(4): 569-580, 2018 04.
Artículo en Inglés | MEDLINE | ID: mdl-29321171

RESUMEN

Although the central nervous system has been implicated in glucocorticoid-induced gain of fat mass, the underlying mechanisms are poorly understood. The aim of this study was to investigate the possible involvement of hypothalamic serum- and glucocorticoid-regulated kinase 1 (SGK1) in glucocorticoid-increased adiposity. It is well known that SGK1 expression is induced by acute glucocorticoid treatment, but it is interesting that we found its expression to be decreased in the arcuate nucleus of the hypothalamus, including proopiomelanocortin (POMC) neurons, following chronic dexamethasone (Dex) treatment. To study the role of SGK1 in POMC neurons, we produced mice that developed or experienced adult-onset SGK1 deletion in POMC neurons (PSKO). As observed in Dex-treated mice, PSKO mice exhibited increased adiposity and decreased energy expenditure. Mice overexpressing constitutively active SGK1 in POMC neurons consistently had the opposite phenotype and did not experience Dex-increased adiposity. Finally, Dex decreased hypothalamic α-melanocyte-stimulating hormone (α-MSH) content and its precursor Pomc expression via SGK1/FOXO3 signaling, and intracerebroventricular injection of α-MSH or adenovirus-mediated FOXO3 knockdown in the arcuate nucleus largely reversed the metabolic alterations in PSKO mice. These results demonstrate that POMC SGK1/FOXO3 signaling mediates glucocorticoid-increased adiposity, providing new insights into the mechanistic link between glucocorticoids and fat accumulation and important hints for possible treatment targets for obesity.


Asunto(s)
Adiposidad/efectos de los fármacos , Dexametasona/farmacología , Proteína Forkhead Box O3/genética , Glucocorticoides/farmacología , Proteínas Inmediatas-Precoces/genética , Neuronas/efectos de los fármacos , Proopiomelanocortina/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Adiposidad/genética , Animales , Núcleo Arqueado del Hipotálamo/efectos de los fármacos , Núcleo Arqueado del Hipotálamo/metabolismo , Metabolismo Energético/efectos de los fármacos , Proteína Forkhead Box O3/metabolismo , Hipotálamo/citología , Hipotálamo/efectos de los fármacos , Hipotálamo/metabolismo , Proteínas Inmediatas-Precoces/metabolismo , Masculino , Ratones , Neuronas/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , alfa-MSH/efectos de los fármacos , alfa-MSH/metabolismo
20.
Neuron ; 96(1): 190-206.e7, 2017 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-28957668

RESUMEN

Sodium deficiency increases angiotensin II (ATII) and aldosterone, which synergistically stimulate sodium retention and consumption. Recently, ATII-responsive neurons in the subfornical organ (SFO) and aldosterone-sensitive neurons in the nucleus of the solitary tract (NTSHSD2 neurons) were shown to drive sodium appetite. Here we investigate the basis for NTSHSD2 neuron activation, identify the circuit by which NTSHSD2 neurons drive appetite, and uncover an interaction between the NTSHSD2 circuit and ATII signaling. NTSHSD2 neurons respond to sodium deficiency with spontaneous pacemaker-like activity-the consequence of "cardiac" HCN and Nav1.5 channels. Remarkably, NTSHSD2 neurons are necessary for sodium appetite, and with concurrent ATII signaling their activity is sufficient to produce rapid consumption. Importantly, NTSHSD2 neurons stimulate appetite via projections to the vlBNST, which is also the effector site for ATII-responsive SFO neurons. The interaction between angiotensin signaling and NTSHSD2 neurons provides a neuronal context for the long-standing "synergy hypothesis" of sodium appetite regulation.


Asunto(s)
Aldosterona/fisiología , Angiotensina II/fisiología , Relojes Biológicos/fisiología , Neuronas/fisiología , Transducción de Señal , Sodio/fisiología , Núcleo Solitario/fisiología , Animales , Ingestión de Alimentos/fisiología , Canales Regulados por Nucleótidos Cíclicos Activados por Hiperpolarización/fisiología , Masculino , Ratones , Ratones Transgénicos , Canal de Sodio Activado por Voltaje NAV1.5/fisiología , Vías Nerviosas/fisiología , Núcleos Septales/fisiología , Sodio/deficiencia
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