26 research outputs found
Notch Simultaneously Orchestrates Multiple Helper T Cell Programs Independently of Cytokine Signals
SummaryTwo models are proposed to explain Notch function during helper T (Th) cell differentiation. One argues that Notch instructs one Th cell fate over the other, whereas the other posits that Notch function is dictated by cytokines. Here we provide a detailed mechanistic study investigating the role of Notch in orchestrating Th cell differentiation. Notch neither instructed Th cell differentiation nor did cytokines direct Notch activity, but instead, Notch simultaneously regulated the Th1, Th2, and Th17 cell genetic programs independently of cytokine signals. In addition to regulating these programs in both polarized and nonpolarized Th cells, we identified Ifng as a direct Notch target. Notch bound the Ifng CNS-22 enhancer, where it synergized with Tbet at the promoter. Thus, Notch acts as an unbiased amplifier of Th cell differentiation. Our data provide a paradigm for Notch in hematopoiesis, with Notch simultaneously orchestrating multiple lineage programs, rather than restricting alternate outcomes
Cosmological Constraints from the Clustering of the Sloan Digital Sky Survey DR7 Luminous Red Galaxies
We present the power spectrum of the reconstructed halo density field derived
from a sample of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey
Seventh Data Release (DR7). The halo power spectrum has a direct connection to
the underlying dark matter power for k <= 0.2 h/Mpc, well into the quasi-linear
regime. This enables us to use a factor of ~8 more modes in the cosmological
analysis than an analysis with kmax = 0.1 h/Mpc, as was adopted in the SDSS
team analysis of the DR4 LRG sample (Tegmark et al. 2006). The observed halo
power spectrum for 0.02 < k < 0.2 h/Mpc is well-fit by our model: chi^2 = 39.6
for 40 degrees of freedom for the best fit LCDM model. We find \Omega_m h^2 *
(n_s/0.96)^0.13 = 0.141^{+0.009}_{-0.012} for a power law primordial power
spectrum with spectral index n_s and \Omega_b h^2 = 0.02265 fixed, consistent
with CMB measurements. The halo power spectrum also constrains the ratio of the
comoving sound horizon at the baryon-drag epoch to an effective distance to
z=0.35: r_s/D_V(0.35) = 0.1097^{+0.0039}_{-0.0042}. Combining the halo power
spectrum measurement with the WMAP 5 year results, for the flat LCDM model we
find \Omega_m = 0.289 +/- 0.019 and H_0 = 69.4 +/- 1.6 km/s/Mpc. Allowing for
massive neutrinos in LCDM, we find \sum m_{\nu} < 0.62 eV at the 95% confidence
level. If we instead consider the effective number of relativistic species Neff
as a free parameter, we find Neff = 4.8^{+1.8}_{-1.7}. Combining also with the
Kowalski et al. (2008) supernova sample, we find \Omega_{tot} = 1.011 +/- 0.009
and w = -0.99 +/- 0.11 for an open cosmology with constant dark energy equation
of state w.Comment: 26 pages, 19 figures, submitted to MNRAS. The power spectrum and a
module to calculate the likelihoods is publicly available at
http://lambda.gsfc.nasa.gov/toolbox/lrgdr/ . v2 fixes abstract formatting
issu
Testing cosmological structure formation using redshift-space distortions
Observations of redshift-space distortions in spectroscopic galaxy surveys
offer an attractive method for observing the build-up of cosmological
structure. In this paper we develop and test a new statistic based on
anisotropies in the measured galaxy power spectrum, which is independent of
galaxy bias and matches the matter power spectrum shape on large scales. The
amplitude provides a constraint on the derivative of the linear growth rate
through f.sigma_8. This demonstrates that spectroscopic galaxy surveys offer
many of the same advantages as weak lensing surveys, in that they both use
galaxies as test particles to probe all matter in the Universe. They are
complementary as redshift-space distortions probe non-relativistic velocities
and therefore the temporal metric perturbations, while weak lensing tests the
sum of the temporal and spatial metric perturbations. The degree to which our
estimator can be pushed into the non-linear regime is considered and we show
that a simple Gaussian damping model, similar to that previously used to model
the behaviour of the power spectrum on very small scales, can also model the
quasi-linear behaviour of our estimator. This enhances the information that can
be extracted from surveys for LCDM models.Comment: 12 pages, 7 figures, version accepted for publication in MNRA
The 6dF Galaxy Survey: z \approx 0 measurement of the growth rate and sigma_8
We present a detailed analysis of redshift-space distortions in the two-point
correlation function of the 6dF Galaxy Survey (6dFGS). The K-band selected
sub-sample which we employ in this study contains 81971 galaxies distributed
over 17000deg^2 with an effective redshift z = 0.067. By modelling the 2D
galaxy correlation function, xi(r_p,pi), we measure the parameter combination
f(z)sigma_8(z) = 0.423 +/- 0.055. Alternatively, by assuming standard gravity
we can break the degeneracy between sigma_8 and the galaxy bias parameter, b.
Combining our data with the Hubble constant prior from Riess et al (2011), we
measure sigma_8 = 0.76 +/- 0.11 and Omega_m = 0.250 +/- 0.022, consistent with
constraints from other galaxy surveys and the Cosmic Microwave Background data
from WMAP7. Combining our measurement of fsigma_8 with WMAP7 allows us to test
the relationship between matter and gravity on cosmic scales by constraining
the growth index of density fluctuations, gamma. Using only 6dFGS and WMAP7
data we find gamma = 0.547 +/- 0.088, consistent with the prediction of General
Relativity. We note that because of the low effective redshift of 6dFGS our
measurement of the growth rate is independent of the fiducial cosmological
model (Alcock-Paczynski effect). We also show that our conclusions are not
sensitive to the model adopted for non-linear redshift-space distortions. Using
a Fisher matrix analysis we report predictions for constraints on fsigma_8 for
the WALLABY survey and the proposed TAIPAN survey. The WALLABY survey will be
able to measure fsigma_8 with a precision of 4-10%, depending on the modelling
of non-linear structure formation. This is comparable to the predicted
precision for the best redshift bins of the Baryon Oscillation Spectroscopic
Survey (BOSS), demonstrating that low-redshift surveys have a significant role
to play in future tests of dark energy and modified gravity.Comment: 17 pages, 13 figures, 1 tabl
Protocol for the development of a core outcome set for stillbirth care research (iCHOOSE Study)
IntroductionStillbirth is associated with significant physical, psychosocial and economic consequences for parents, families, wider society and the healthcare system. There is emerging momentum to design and evaluate interventions for care after stillbirth and in subsequent pregnancies. However, there is insufficient evidence to inform clinical practice compounded by inconsistent outcome reporting in research studies. To address this paucity of evidence, we plan to develop a core outcome set for stillbirth care research, through an international consensus process with key stakeholders including parents, healthcare professionals and researchers.Methods and analysisThe development of this core outcome set will be divided into five distinct phases: (1) Identifying potential outcomes from a mixed-methods systematic review and analysis of interviews with parents who have experienced stillbirth; (2) Creating a comprehensive outcome long-list and piloting of a Delphi questionnaire using think-aloud interviews; (3) Choosing the most important outcomes by conducting an international two-round Delphi survey including high-income, middle-income and low-income countries; (4) Deciding the core outcome set by consensus meetings with key stakeholders and (5) Dissemination and promotion of the core outcome set. A parent and public involvement panel and international steering committee has been convened to coproduce every stage of the development of this core outcome set.Ethics and disseminationEthical approval for the qualitative interviews has been approved by Berkshire Ethics Committee REC Reference 12/SC/0495. Ethical approval for the think-aloud interviews, Delphi survey and consensus meetings has been awarded from the University of Bristol Faculty of Health Sciences Research Ethics Committee (Reference number: 116535). The dissemination strategy is being developed with the parent and public involvement panel and steering committee. Results will be published in peer-reviewed specialty journals, shared at national and international conferences and promoted through parent organisations and charities.PROSPERO registration numberCRD42018087748.</jats:sec
Novel Foxo1-dependent transcriptional programs control Treg cell function
Regulatory T (T(reg)) cells, characterized by expression of the transcription factor forkhead box P3 (Foxp3), maintain immune homeostasis by suppressing self-destructive immune responses. Foxp3 operates as a late-acting differentiation factor controlling T(reg) cell homeostasis and function, whereas the early T(reg)-cell-lineage commitment is regulated by the Akt kinase and the forkhead box O (Foxo) family of transcription factors. However, whether Foxo proteins act beyond the T(reg)-cell-commitment stage to control T(reg) cell homeostasis and function remains largely unexplored. Here we show that Foxo1 is a pivotal regulator of T(reg )cell function. T(reg) cells express high amounts of Foxo1 and display reduced T-cell-receptor-induced Akt activation, Foxo1 phosphorylation and Foxo1 nuclear exclusion. Mice with T(reg)-cell-specific deletion of Foxo1 develop a fatal inflammatory disorder similar in severity to that seen in Foxp3-deficient mice, but without the loss of T(reg) cells. Genome-wide analysis of Foxo1 binding sites reveals ~300 Foxo1-bound target genes, including the pro-inflammatory cytokine Ifng, that do not seem to be directly regulated by Foxp3. These findings show that the evolutionarily ancient Akt-Foxo1 signalling module controls a novel genetic program indispensable for T(reg) cell function