BackgroundKlotho was originally characterized as an anti-aging gene that predisposed Klotho-deficient mice to a premature aging-like syndrome. Recently, KLOTHO was reported to function as a secreted Wnt antagonist and as a tumor suppressor. Epigenetic gene silencing of secreted Wnt antagonists is considered a common event in a wide range of human malignancies. Abnormal activation of the canonical Wnt pathway due to epigenetic deregulation of Wnt antagonists is thought to play a crucial role in cervical tumorigenesis. In this study, we examined epigenetic silencing of KLOTHO in human cervical carcinoma.ResultsLoss of KLOTHO mRNA was observed in several cervical cancer cell lines and in invasive carcinoma samples, but not during the early, preinvasive phase of primary cervical tumorigenesis. KLOTHO mRNA was restored after treatment with either the DNA demethylating agent 2'-deoxy-5-azacytidine or histone deacetylase inhibitor trichostatin A. Methylation-specific PCR and bisulfite genomic sequencing analysis of the promoter region of KLOTHO revealed CpG hypermethylation in non-KLOTHO-expressing cervical cancer cell lines and in 41% (9/22) of invasive carcinoma cases. Histone deacetylation was also found to be the major epigenetic silencing mechanism for KLOTHO in the SiHa cell line. Ectopic expression of the secreted form of KLOTHO restored anti-Wnt signaling and anti-clonogenic activity in the CaSki cell line including decreased active β-catenin levels, suppression of T-cell factor/β-catenin target genes, such as c-MYC and CCND1, and inhibition of colony growth.ConclusionsEpigenetic silencing of KLOTHO may occur during the late phase of cervical tumorigenesis, and consequent functional loss of KLOTHO as the secreted Wnt antagonist may contribute to aberrant activation of the canonical Wnt pathway in cervical carcinoma.
For the next step fusion reactor the use of tungsten is inevitable to suppress erosion and allow operation at elevated temperature and high heat loads. Tungsten fibre-reinforced composites overcome the intrinsic brittleness of tungsten and its susceptibility to operation embrittlement and thus allow its use as a structural as well as an armour material. That this concept works in principle has been shown in recent years. In this contribution we present a development approach towards their use in a future fusion reactor. A multilayer approach is needed addressing all composite constituents and manufacturing steps. A huge potential lies in the optimization of the tungsten wire used as fibre. We discuss this aspect and present studies on potassium doped tungsten wire in detail. This wire, utilized in the illumination industry, could be a replacement of the so far used pure tungsten wire due to its superior high temperature properties. In tensile tests the wire showed high strength and ductility up to an annealing temperature of 2200 K. The results show that the use of doped tungsten wire could increase the allowed fabrication temperature and the overall working temperature of the composite itself.
The tacticity effect on phase separation process of poly(N-isopropylacrylamide) (PNiPAM) aqueous solutions was investigated by dynamic light scattering (DLS) and small angle neutron scattering (SANS) measurements. SANS measurement revealed that hydrophobicity of PNiPAM consisting of meso- and racemo-isomers increased with increasing the meso-content. This result is in accordance with the result of the previous experimental and simulation study on NiPAM dimers (DNiPAM) and trimers (TNiPAM) [ Katsumoto Y Katsumoto Y J. Phys. Chem. B20101141331213318, and Autieri E. Autieri E. J. Phys. Chem. B201111558275839]; i.e., meso-diad is more hydrophobic than racemo-diad. In addition, a series of scattering experiments revealed that the ratio of meso-diad does not affect the static structure or the shrinking behavior of a single chain, but strongly affects the aggregation behavior. The PNiPAMs with low meso-content suddenly associate around the phase separation temperature, while that of the high meso-content gradually aggregate with increasing temperature. We propose that phase transition behavior of PNiPAM aqueous solutions can be controlled by changing the stereoregularity of the polymer chain.
Airway inflammation is a hallmark of asthma, triggering airway smooth muscle (ASM) hyperreactivity and airway remodeling. TNFα increases both agonist-induced cytosolic Ca concentration ([Ca]) and force in ASM. The effects of TNFα on ASM force may also be due to an increase in Ca sensitivity, cytoskeletal remodeling, and/or changes in contractile protein content. We hypothesized that 24 h of exposure to TNFα increases ASM force by changing actin and myosin heavy chain (MyHC) content and/or polymerization. Porcine ASM strips were permeabilized with 10% Triton X-100, and force was measured in response to increasing concentrations of Ca (pCa 9.0 to 4.0) in control and TNFα-treated groups. Relative phosphorylation of the regulatory myosin light chain (p-MLC) and total actin, MLC, and MyHC concentrations were quantified at pCa 9.0, 6.1, and 4.0. Actin polymerization was quantified by the ratio of filamentous to globular actin at pCa 9.0 and 4.0. For determination of total cross-bridge formation, isometric ATP hydrolysis rate at pCa 4.0 was measured using an enzyme-coupled NADH-linked fluorometric technique. Exposure to TNFα significantly increased force across the range of Ca activation but did not affect the intrinsic Ca sensitivity of force generation. The TNFα-induced increase in ASM force was associated with an increase in total actin, MLC, and MyHC content, as well as an increase in actin polymerization and an increase in maximum isometric ATP hydrolysis rate. The results of this study support our hypothesis that TNFα increases force generation in ASM by increasing the number of contractile units (actin-myosin content) contributing to force generation.
A robust hydrogel with a reliable deformation region in an aqueous environment is proposed. The gel has a homogeneous network where hydrophilic/hydrophobic components are uniformly distributed. In an aqueous environment, aggregated hydrophobic segments serve as "mechanical fuse links," inhibiting sudden macroscopic fracture. The gel endures threefold stretching for more than 100 cycles in water without mechanical hysteresis.
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