Presentation_1_Progesterone Modulation of Pregnancy-Related Immune Responses.PDF

<p>Progesterone (P4) is an important steroid hormone for the establishment and maintenance of pregnancy and its functional withdrawal in reproductive tissue is linked with the onset of parturition. However, the effects of P4 on adaptive immune responses are poorly understood. In this study, we took a novel approach by comparing the effects of P4 supplementation longitudinally, with treatment using a P4 antagonist mifepristone (RU486) in mid-trimester pregnancies. Thus, we were able to demonstrate the immune-modulatory functions of P4. We show that, in pregnancy, the immune system is increasingly activated (CD38, CCR6) with greater antigen-specific cytotoxic T cell responses (granzyme B). Simultaneously, pregnancy promotes a tolerant immune environment (IL-10 and regulatory-T cells) that gradually reverses prior to the onset of labor. P4 suppresses and RU486 enhances antigen-specific CD4 and CD8 T cell inflammatory cytokine (IFN-γ) and cytotoxic molecule release (granzyme B). P4 and RU486 effectively modulate immune cell-mediated interactions, by regulating differentiated memory T cell subset sensitivity to antigen stimulation. Our results indicate that P4 and RU486, as immune modulators, share a reciprocal relationship. These data unveil key contributions of P4 to the modulation of the maternal immune system and suggests targets for future modulation of maternal immune function during pregnancy.</p

A New <i>n</i> = 4 Layered Ruddlesden–Popper Phase K_2.5Bi_2.5Ti₄O₁₃ Showing Stoichiometric Hydration

A new bismuth-containing layered perovskite of the Ruddlesden–Popper type, K_2.5Bi_2.5Ti₄O₁₃, has been prepared by solid-state synthesis. It has been shown to hydrate to form stoichiometric K_2.5Bi_2.5Ti₄O₁₃·H₂O. Diffraction data show that the structure consists of a quadruple-stacked (<i>n</i> = 4) perovskite layer, with potassium ions occupying the rock salt layer and its next-nearest A site. The hydrated sample was shown to remove the offset between stacked perovskite layers relative to the dehydrated sample. Computational methods show that the hydrated phase consists of intact H₂O molecules in a vertical “pillared” arrangement bridging across the interlayer space. Rotations of H₂O molecules about the <i>c</i> axis were evident in molecular dynamic calculations, which increased in rotation angle with increasing temperature. In situ diffraction data for the dehydrated phase point to a broad structural phase transition from orthorhombic to tetragonal at ∼600 °C. The relative bismuth-rich composition in the perovskite block results in a higher transition temperature compared to related perovskite structures. Water makes a significant contribution to the dielectric constant, which disappears after dehydration

A New <i>n</i> = 4 Layered Ruddlesden–Popper Phase K_2.5Bi_2.5Ti₄O₁₃ Showing Stoichiometric Hydration

A new bismuth-containing layered perovskite of the Ruddlesden–Popper type, K_2.5Bi_2.5Ti₄O₁₃, has been prepared by solid-state synthesis. It has been shown to hydrate to form stoichiometric K_2.5Bi_2.5Ti₄O₁₃·H₂O. Diffraction data show that the structure consists of a quadruple-stacked (<i>n</i> = 4) perovskite layer, with potassium ions occupying the rock salt layer and its next-nearest A site. The hydrated sample was shown to remove the offset between stacked perovskite layers relative to the dehydrated sample. Computational methods show that the hydrated phase consists of intact H₂O molecules in a vertical “pillared” arrangement bridging across the interlayer space. Rotations of H₂O molecules about the <i>c</i> axis were evident in molecular dynamic calculations, which increased in rotation angle with increasing temperature. In situ diffraction data for the dehydrated phase point to a broad structural phase transition from orthorhombic to tetragonal at ∼600 °C. The relative bismuth-rich composition in the perovskite block results in a higher transition temperature compared to related perovskite structures. Water makes a significant contribution to the dielectric constant, which disappears after dehydration

Polymorphism and Oxide Ion Migration Pathways in Fluorite-Type Bismuth Vanadate, Bi₄₆V₈O₈₉

We report the synthesis, structural characterization, and ionic conductivity measurements for a new polymorph of bismuth vanadate Bi₄₆V₈O₈₉, and an <i>ab initio</i> molecular dynamics study of this oxide ion conductor. Structure determination was carried out using synchrotron powder X-ray and neutron diffraction data; it was found that β-Bi₄₆V₈O₈₉ crystallizes in space group <i>C</i>2/<i>m</i> and that the key differences between this and the previously reported α-form are the distribution of Bi and V cations and the arrangement of the VO₄ coordination polyhedra in structure. β-Bi₄₆V₈O₈₉ exhibits good oxide ion conductivity, with σ = 0.01–0.1 S/cm between 600 and 850 °C, which is about an order of magnitude higher than yttria stabilized zirconia. The <i>ab initio</i> molecular dynamics simulations suggest that the ion migration pathways include vacancy diffusion through the Bi–O sublattice, as well as the O^2– exchanges between the Bi–O and the V–O sublattices, facilitated by the variability of the vanadium coordination environment and the rotational freedom of the VO_<i>x</i> coordination polyhedra

Polymorphism and Oxide Ion Migration Pathways in Fluorite-Type Bismuth Vanadate, Bi₄₆V₈O₈₉

We report the synthesis, structural characterization, and ionic conductivity measurements for a new polymorph of bismuth vanadate Bi₄₆V₈O₈₉, and an <i>ab initio</i> molecular dynamics study of this oxide ion conductor. Structure determination was carried out using synchrotron powder X-ray and neutron diffraction data; it was found that β-Bi₄₆V₈O₈₉ crystallizes in space group <i>C</i>2/<i>m</i> and that the key differences between this and the previously reported α-form are the distribution of Bi and V cations and the arrangement of the VO₄ coordination polyhedra in structure. β-Bi₄₆V₈O₈₉ exhibits good oxide ion conductivity, with σ = 0.01–0.1 S/cm between 600 and 850 °C, which is about an order of magnitude higher than yttria stabilized zirconia. The <i>ab initio</i> molecular dynamics simulations suggest that the ion migration pathways include vacancy diffusion through the Bi–O sublattice, as well as the O^2– exchanges between the Bi–O and the V–O sublattices, facilitated by the variability of the vanadium coordination environment and the rotational freedom of the VO_<i>x</i> coordination polyhedra

Local Structure, Dynamics, and the Mechanisms of Oxide Ionic Conduction in Bi₂₆Mo₁₀O₆₉

We report the results of a computational and experimental study into the stabilized fluorite-type δ-Bi₂O₃-related phase Bi₂₆Mo₁₀O₆₉ aimed at clarifying the local and average structure, for which two distinct models have previously been proposed, and the oxide ionic diffusion mechanism, for which three distinct models have previously been proposed. Concerning the structure, we propose a new model in which some molybdenum atoms have higher coordination numbers than 4; that is, some MoO₅ trigonal bipyramids coexist with MoO₄ tetrahedra. This accounts for the additional oxygen required to achieve the nominal composition (a tetrahedron-only model gives Bi₂₆Mo₁₀O₆₈) without invoking a previously proposed unbonded interstitial site, which we found to be energetically unfavorable. All these MoO_<i>x</i> units are rotationally disordered above a first-order transition at 310 °C, corresponding to a first-order increase in conductivity. Concerning oxide ionic diffusion above that transition temperature, we found excellent agreement between the results of ab initio molecular dynamics simulations and quasielastic neutron scattering experiments. Our results indicate a mechanism related to that proposed by Holmes et al. (<i>Chem. Mater.</i> <b>2008</b>, <i>20</i>, 3638), with the role previously assigned to partially occupied interstitial oxygen sites played instead by transient but stable MoO₅ trigonal bipyramids and with more relaxed requirements in terms of the orientation and timing of the diffusive jumps

Direct Observation of Oxide Ion Dynamics in La₂Mo₂O₉ on the Nanosecond Timescale

Quasielastic neutron scattering (QENS), underpinned by ab initio molecular dynamics (AIMD) simulations, has been used to directly observe oxide ion dynamics in solid electrolyte La₂Mo₂O₉ on the nanosecond timescale, the longest timescale probed in oxide ion conductors by neutron scattering to date. QENS gives the activation energy of 0.61(5) eV for this process, while AIMD simulations reveal that the exchange processes, which ultimately lead to long-range oxide ion diffusion in La₂Mo₂O₉, rely on the flexibility of the coordination environment around Mo⁶⁺, with oxide ions jumps occurring between vacant sites both within and between Mo coordination spheres. Simulations also differentiate between the crystallographic sites which participate in the oxide ion exchange processes, offering the first atomic-level understanding of the oxide ion dynamics in La₂Mo₂O₉, which is consistent with the macroscopic experimental observations on this material

Progesterone Acts via the Nuclear Glucocorticoid Receptor to Suppress IL-1β-Induced COX-2 Expression in Human Term Myometrial Cells

<div><p>Progesterone is widely used to prolong gestation in women at risk of preterm labour (PTL), and acts at least in part via the inhibition of inflammatory cytokine-induced prostaglandin synthesis. This study investigates the mechanisms responsible for this inhibition in human myometrial cells. We used reporter constructs to demonstrate that interleukin 1beta (IL-1β) inhibits progesterone driven PRE activation via p65 activation and that IL-1β reduced progesterone driven gene expression (FKBP5). Conversely, we found that the activity of a p65-driven NFκB reporter construct was reduced by overexpression of progesterone receptor B (PRB) alone and that this was enhanced by the addition of MPA and that both MPA and progesterone suppressed IL-1β-driven cyclo-oxygenase-2 (COX-2) expression. We found that over-expressed Halo-tagged PRB, but not PRA, bound to p65 and that in IL-1β-treated cells, with no overexpression of either PR or p65, activated p65 bound to PR. However, we found that the ability of MPA to repress IL-1β-driven COX-2 expression was not enhanced by overexpression of either PRB or PRA and that although the combined PR and GR antagonist Ru486 blocked the effects of progesterone and MPA, the specific PR antagonist, Org31710, did not, suggesting that progesterone and MPA act via GR and not PR. Knockdown using siRNA confirmed that both MPA and progesterone acted via GR and not PR or AR to repress IL-1β-driven COX-2 expression. We conclude that progesterone acts via GR to repress IL-1β-driven COX-2 activation and that although the interaction between p65 and PRB may be involved in the repression of progesterone driven gene expression it does not seem to be responsible for progesterone repression of IL-1β-induced COX-2 expression.</p> </div

Effect of PR modulation on progesterone inhibition of IL-1β-driven COX-2 expression.

<p><b>A and B,</b> Myometrial cells were transfected with PRB or PRA. SG5 was used as control. MPA and IL-1β, either alone or in combination were added 48 h after transfection and the cells were incubated for another 6 h. mRNA was then extracted, and the COX-2 mRNA levels were measured using qPCR. Data are expressed as median, 25^th and 75^th percentiles and range, and were analysed using Wilcoxon matched pairs test. *indicates a significant difference of <i>p</i><0.05 and **, of <i>P</i><0.01; NS indicates no statistic significant difference (n = 6). <b>C,</b> Myometrial cells were pre-incubated with Org31710 (1 µM) or Ru486 (1 µM) for 2 h before being exposed to different stimuli, IL-1β, MPA and progesterone, either alone or in combination. mRNA was then extracted, and the COX-2 mRNA levels were measured using qPCR. Data are expressed as median, 25^th and 75^th percentiles and range, and were analysed using paired <i>t</i> test. *indicates a significant difference of <i>p</i><0.05; NS indicates no statistic significant difference (n = 6). <b>D,</b> Myometrial cells were transfected with different siRNAs against PR (siPR), GR (siGR) and AR (siAR), respectively. Non-targeting siRNA (siNT) was used as control. After transfection, cells were incubated for 96 h before being exposed to different stimuli, IL-1β, MPA and progesterone, either alone or in combination. mRNA was then extracted, and the COX-2 mRNA levels were measured using qPCR. Data are expressed as median, 25^th and 75^th percentiles and range, and were analysed using paired <i>t</i> test. **indicates a significant difference of <i>p</i><0.01 and ***, of <i>P</i><0.001; NS indicates no statistic significant difference (n = 6).</p

ON-TARGET plus SMART pool siRNA sequences.

<p>ON-TARGET plus SMART pool siRNA sequences.</p