Identification and characterization of estrogen receptor-regulated gene expression programs

The physiological effects of natural and synthetic estrogens are mediated by estrogen receptor alpha (ER alpha), and estrogen receptor beta (ER beta). Within the nucleus of target cells, ER alpha and ER beta serve as ligand-activated transcription factors to stimulate or repress the transcription of estrogen receptor regulated genes. ER alpha and ER beta may be co-expressed in estrogen-responsive cells, but may also be differentially expressed in a cell- and tissue-specific manner. In addition, within a given context these two receptors have different ligand binding and transcriptional activities. Taken together, these attributes underlie differences in target gene regulation, and overall, different physiological actions by ER subtypes. The work described here is an attempt to understand the roles of ER alpha and ER beta in target tissues (e.g. bone, breast, uterus) including the gene networks and cell signaling pathways under ER regulation. We have also characterized the regulation of one of the ER-regulated genes, Carbonic Anhydrase XII, and examined its regulation by ER alpha through use of a conserved distal enhancer. The work described here reports the characterization of individual gene regulatory actions of ER alpha and ER beta. To investigate the individual actions of ER alpha or ER beta, we utilized Affymetrix oligonucleotide arrays to profile transcripts regulated by 17beta-estradiol (E2) in U2OS-ER alpha and U2OS-ER beta cells. These cell lines were constructed by stable integration of ER alpha or ER beta into human osteoblast-like U2OS osteosarcoma cells and initially characterized for ER subtype expression, E2-binding, and cellular responses to E2, including proliferation, motility, and adhesion. Cells expressing apo-ER alpha or apo-ER beta did not show significant alteration in adhesion or proliferation after addition of E2, however there was a significant stimulation of migration in E2-treated ER beta-expressing cells. U2OS-ER alpha, and U2OS-ER beta cells were treated with 10 nM E2 for 0, 4, 8, 24, and 48 hours and total RNA was collected and hybridized to Affymetryx U95Av2 GeneChips and subjected to a Confidence Score to determine E2-regulated RNAs. Of the ca. 100 stimulated or repressed genes identified, some were stimulated by E2 equally through ER alpha and ER beta, whereas others were selectively stimulated via ER alpha or ER beta. The E2-regulated genes showed three distinct temporal patterns of expression over the 48 hour time course studied. Among stimulated genes, ER alpha-containing cells exhibited a greater number of regulated transcripts, and overall magnitude of stimulation was increased as compared those regulated by ER beta. Of the functional categories of the E2-regulated genes, most numerous were those encoding cytokines and factors associated with immune response, signal transduction, and cell migration and cytoskeleton regulation, indicating that E2 can exert effects on multiple pathways in these osteoblast-like cell lines. Of note, E2 up-regulated several genes associated with cell motility selectively via ER beta, in keeping with the selective E2 enhancement of the motility of ER beta-containing cells. On genes regulated equally by E2 via ER alpha or ER beta, the phytoestrogen genistein preferentially stimulated gene expression via ER beta. These studies indicate both common as well as distinct target genes for these two ERs, and identify many novel genes not previously known to be under estrogen regulation. We have examined the ER regulation of the Carbonic Anhydrase XII (CA12) gene, a gene identified as E2-regulated in the studies described above. We investigated the expression of CA12 and its and regulation of by 17beta-estradiol and selective estrogen receptor modulators in breast cancer cells, and characterize the ER usage of a distal enhancer necessary for CA12 gene regulation. We find that CA12 expression is highly correlated with ER alpha expression in human breast tumors. We demonstrate that E2 and SERMS increase CA12 mRNA and protein in multiple breast cancer cell types expressing ER alpha, and that CA12 regulation by estrogen is a primary transcriptional response mediated by ER alpha. By genome-wide chromatin immunoprecipitation (ChIP) and ChIP scanning of the CA12 locus, we find E2-occupied ER alpha is recruited to a distal region 6.1 kb upstream of the CA12 transcription start site (TSS) in vivo. We find that E2 treatment results in recruitment of RNA polymerase II and steroid receptor coactivators SRC-2 and SRC-3 to the CA12 genomic locus and is correlated with increased histone H4 acetylation. Mutagenesis of an imperfect estrogen-responsive element within this -6.1kb distal enhancer region abolishes estrogen-dependent heterologous reporter activity. Chromosome conformation capture (3C) and chromatin immunoprecipitation assays demonstrate that this distal enhancer communicates with the transcriptional start site of the CA12 gene via intra-chromosomal looping upon hormone treatment. This distal enhancer element is observed in the homologous mouse genomic sequence, and the expression of the mouse homolog, Car12, is rapidly and robustly stimulated by estradiol in the mouse uterus in vivo, suggesting that the ER regulation of CA12 is mechanistically and evolutionarily conserved. Our findings highlight the crucial role of ER in regulation of the CA12 gene, and provide insight into the transcriptional regulatory mechanism that accounts for the strong association of CA12 and ER in human breast cancers. In addition, our findings imply that involvement of long distance enhancers in regulation of estrogen-responsive genes in breast cancer may be more frequent than previously appreciated

Decoherence and dephasing errors caused by D.C. Stark effect in rapid ion transport

We investigate the error due to D.C. Stark effect for quantum information processing for trapped ion quantum computers using the scalable architecture proposed in J. Res. Natl. Inst. Stan. 103, 259 (1998) and Nature 417, 709 (2002). As the operation speed increases, dephasing and decoherence due to the D.C. Stark effect becomes prominent as a large electric field is applied for transporting ions rapidly. We estimate the relative significance of the decoherence and dephasing effects and find that the latter is dominant. We find that the minimum possible of dephasing is quadratic in the time of flight, and an inverse cubic in the operational time scale. From these relations, we obtain the operational speed-range at which the shifts caused by D.C. Stark effect, no matter follow which trajectory the ion is transported, are no longer negligible. Without phase correction, the maximum speed a qubit can be transferred across a 100 micron-long trap, without excessive error, in about 10 ns for Calcium ion and 50 ps for Beryllium ion. In practice, the accumulated error is difficult to be tracked and calculated, our work gives an estimation to the range of speed limit imposed by D.C. Stark effect.Comment: 7 pages, 1 figure. v2: Title is changed in this version to make our argument more focused. Introduction is rewritten. A new section IV is added to make our point more prominent. v3: Title is changed to make our argument more specific. Abstract, introduction, and summary are revise

Effect of Intragastric pH on the Absorption of Oral Zinc Acetate and Zinc Oxide in Young Healthy Volunteers

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142255/1/jpen0393.pd

Chaos in a double driven dissipative nonlinear oscillator

We propose an anharmonic oscillator driven by two periodic forces of different frequencies as a new time-dependent model for investigating quantum dissipative chaos. Our analysis is done in the frame of statistical ensemble of quantum trajectories in quantum state diffusion approach. Quantum dynamical manifestation of chaotic behavior, including the emergence of chaos, properties of strange attractors, and quantum entanglement are studied by numerical simulation of ensemble averaged Wigner function and von Neumann entropy.Comment: 9 pages, 18 figure

Atom laser coherence and its control via feedback

We present a quantum-mechanical treatment of the coherence properties of a single-mode atom laser. Specifically, we focus on the quantum phase noise of the atomic field as expressed by the first-order coherence function, for which we derive analytical expressions in various regimes. The decay of this function is characterized by the coherence time, or its reciprocal, the linewidth. A crucial contributor to the linewidth is the collisional interaction of the atoms. We find four distinct regimes for the linewidth with increasing interaction strength. These range from the standard laser linewidth, through quadratic and linear regimes, to another constant regime due to quantum revivals of the coherence function. The laser output is only coherent (Bose degenerate) up to the linear regime. However, we show that application of a quantum nondemolition measurement and feedback scheme will increase, by many orders of magnitude, the range of interaction strengths for which it remains coherent.Comment: 15 pages, 6 figures, revtex

Bipartite Entanglement in Continuous-Variable Cluster States

We present a study of the entanglement properties of Gaussian cluster states, proposed as a universal resource for continuous-variable quantum computing. A central aim is to compare mathematically-idealized cluster states defined using quadrature eigenstates, which have infinite squeezing and cannot exist in nature, with Gaussian approximations which are experimentally accessible. Adopting widely-used definitions, we first review the key concepts, by analysing a process of teleportation along a continuous-variable quantum wire in the language of matrix product states. Next we consider the bipartite entanglement properties of the wire, providing analytic results. We proceed to grid cluster states, which are universal for the qubit case. To extend our analysis of the bipartite entanglement, we adopt the entropic-entanglement width, a specialized entanglement measure introduced recently by Van den Nest M et al., Phys. Rev. Lett. 97 150504 (2006), adapting their definition to the continuous-variable context. Finally we add the effects of photonic loss, extending our arguments to mixed states. Cumulatively our results point to key differences in the properties of idealized and Gaussian cluster states. Even modest loss rates are found to strongly limit the amount of entanglement. We discuss the implications for the potential of continuous-variable analogues of measurement-based quantum computation.Comment: 22 page

Characterizing Hospital Workers' Willingness to Respond to a Radiological Event

Terrorist use of a radiological dispersal device (RDD, or "dirty bomb"), which combines a conventional explosive device with radiological materials, is among the National Planning Scenarios of the United States government. Understanding employee willingness to respond is critical for planning experts. Previous research has demonstrated that perception of threat and efficacy is key in the assessing willingness to respond to a RDD event.An anonymous online survey was used to evaluate the willingness of hospital employees to respond to a RDD event. Agreement with a series of belief statements was assessed, following a methodology validated in previous work. The survey was available online to all 18,612 employees of the Johns Hopkins Hospital from January to March 2009.Surveys were completed by 3426 employees (18.4%), whose demographic distribution was similar to overall hospital staff. 39% of hospital workers were not willing to respond to a RDD scenario if asked but not required to do so. Only 11% more were willing if required. Workers who were hesitant to agree to work additional hours when required were 20 times less likely to report during a RDD emergency. Respondents who perceived their peers as likely to report to work in a RDD emergency were 17 times more likely to respond during a RDD event if asked. Only 27.9% of the hospital employees with a perception of low efficacy declared willingness to respond to a severe RDD event. Perception of threat had little impact on willingness to respond among hospital workers.Radiological scenarios such as RDDs are among the most dreaded emergency events yet studied. Several attitudinal indicators can help to identify hospital employees unlikely to respond. These risk-perception modifiers must then be addressed through training to enable effective hospital response to a RDD event

The Kölliker-Fuse orchestrates the timing of expiratory abdominal nerve bursting

Coordination of respiratory pump and valve muscle activity is essential for normal breathing. A hallmark respiratory response to hypercapnia and hypoxia is the emergence of active exhalation, characterized by abdominal muscle pumping during the late one-third of expiration (late-E phase). Late-E abdominal activity during hypercapnia has been attributed to the activation of expiratory neurons located within the parafacial respiratory group (pFRG). However, the mechanisms that control emergence of active exhalation, and its silencing in restful breathing, are not completely understood. We hypothesized that inputs from the Kölliker-Fuse nucleus (KF) control the emergence of late-E activity during hypercapnia. Previously, we reported that reversible inhibition of the KF reduced postinspiratory (post-I) motor output to laryngeal adductor muscles and brought forward the onset of hypercapnia-induced late-E abdominal activity. Here we explored the contribution of the KF for late-E abdominal recruitment during hypercapnia by pharmacologically disinhibiting the KF in in situ decerebrate arterially perfused rat preparations. These data were combined with previous results and incorporated into a computational model of the respiratory central pattern generator. Disinhibition of the KF through local parenchymal microinjections of gabazine (GABAA receptor antagonist) prolonged vagal post-I activity and inhibited late-E abdominal output during hypercapnia. In silico, we reproduced this behavior and predicted a mechanism in which the KF provides excitatory drive to post-I inhibitory neurons, which in turn inhibit late-E neurons of the pFRG. Although the exact mechanism proposed by the model requires testing, our data confirm that the KF modulates the formation of late-E abdominal activity during hypercapnia. NEW &amp; NOTEWORTHY The pons is essential for the formation of the three-phase respiratory pattern, controlling the inspiratory-expiratory phase transition. We provide functional evidence of a novel role for the Kölliker-Fuse nucleus (KF) controlling the emergence of abdominal expiratory bursts during active expiration. A computational model of the respiratory central pattern generator predicts a possible mechanism by which the KF interacts indirectly with the parafacial respiratory group and exerts an inhibitory effect on the expiratory conditional oscillator. </jats:p

Public–private partnership in higher education provision in Tanzania: implications for access to and quality of education

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