CD4+CD25+ Regulatory T Cells Can Mediate Suppressor Function in the Absence of Transforming Growth Factor β1 Production and Responsiveness

CD4+CD25+ regulatory T cells inhibit organ-specific autoimmune diseases induced by CD4+CD25−T cells and are potent suppressors of T cell activation in vitro. Their mechanism of suppression remains unknown, but most in vitro studies suggest that it is cell contact–dependent and cytokine independent. The role of TGF-β1 in CD4+CD25+ suppressor function remains unclear. While most studies have failed to reverse suppression with anti–transforming growth factor (TGF)-β1 in vitro, one recent study has reported that CD4+CD25+ T cells express cell surface TGF-β1 and that suppression can be completely abrogated by high concentrations of anti–TGF-β suggesting that cell-associated TGF-β1 was the primary effector of CD4+CD25+-mediated suppression. Here, we have reevaluated the role of TGF-β1 in CD4+CD25+-mediated suppression. Neutralization of TGF-β1 with either monoclonal antibody (mAb) or soluble TGF-βRII-Fc did not reverse in vitro suppression mediated by resting or activated CD4+CD25+ T cells. Responder T cells from Smad3−/− or dominant-negative TGF-β type RII transgenic (DNRIITg) mice, that are both unresponsive to TGF-β1–induced growth arrest, were as susceptible to CD4+CD25+-mediated suppression as T cells from wild-type mice. Furthermore, CD4+CD25+ T cells from neonatal TGF-β1−/− mice were as suppressive as CD4+CD25+ from TGF-β1+/+ mice. Collectively, these results demonstrate that CD4+CD25+ suppressor function can occur independently of TGF-β1

Soluble selenium content of agricultural soils in Japan and its determining factors with reference to soil type, land use and region

<div><p></p><p>To evaluate labile selenium (Se) content in agricultural soils in Japan and to investigate its determining factors, 178 soil samples were collected from the surface layer of paddy or upland fields in Japan and their soluble Se contents were determined. Two grams of soil was extracted with 20 mL of 0.1 mol L⁻¹ sodium sulfate (Na₂SO₄) solution for 30 min in boiling water, and the released Se was reduced to Se (IV) after organic matter decomposition. The concentration of Se (IV) was then determined by high performance liquid chromatography (HPLC) with a fluorescence detector after treatment with 2,3-diaminonaphthalene (DAN) and extraction with cyclohexane. Soluble Se content ranged from 2.5 to 44.5 μg kg⁻¹ with geometric and arithmetic means of 11.4 and 12.8 μg kg⁻¹, respectively, and corresponded to 3.2% of the total Se on average. The overall data showed log-normal distribution. In terms of soil type, Non-allophanic Andosols and Volcanogenous Regosols had relatively high soluble Se content, and Wet Andosols and Lowland Paddy soils had relatively low soluble Se content. In terms of land use, upland soils had significantly higher soluble Se content than paddy soils (p < 0.01). The soluble Se content had significant positive correlation with total organic carbon (TOC) content of the extract, soil pH and total Se content (p < 0.01). In conclusion, total Se content in combination with soil pH was the main determining factor of the soluble Se content of agricultural soils in Japan.</p></div

Identification, Synthesis, and Biological Evaluation of 6‑[(6<i>R</i>)‑2-(4-Fluorophenyl)-6-(hydroxymethyl)-4,5,6,7-tetrahydropyrazolo[1,5‑<i>a</i>]pyrimidin-3-yl]-2-(2-methylphenyl)pyridazin-3(2<i>H</i>)‑one (AS1940477), a Potent p38 MAP Kinase Inhibitor

Several p38 MAPK inhibitors have been shown to effectively block the production of cytokines such as IL-1β, TNFα, and IL-6. Inhibitors of p38 MAP kinase therefore have significant therapeutic potential for the treatment of autoimmune disease. Compound <b>2a</b> was identified as a potent TNFα production inhibitor in vitro but suffered from poor oral bioavailability. Structural modification of <b>2a</b> led to the discovery of tetrahydropyrazolopyrimidine derivatives, exemplified by compound <b>3</b>, with an improved pharmacokinetic profile. We found that blocking metabolism at the methyl group of the amine and constructing the tetrahydropyrimidine core were important to obtaining compounds with good biological profiles and oral bioavailability. Pursuing the structure–activity relationships of this series led to the discovery of AS1940477 (<b>3f</b>), with excellent cellular activity and a favorable pharmacokinetic profile. This compound represents a highly potent inhibitor of p38 MAP kinase with regard to in vivo activity in an adjuvant-induced arthritis model