Zinc selenide nanoparticles (ZnSe NPs) were synthesized in the cavity of the cage-shaped protein apoferritin by designing a slow chemical reaction system, which employs tetraaminezinc ion and selenourea. The chemical synthesis of ZnSe NPs was realized in a spatially selective manner from an aqueous solution, and ZnSe cores were formed in almost all apoferritin cavities with little bulk precipitation. Three factors are found to be important for ZnSe NP synthesis in the apoferritin cavity: (1) the threefold channel, which selectively introduces zinc ion into the apoferritin cavity, (2) the apoferritin internal potential, which favors zinc ion accumulation in the cavity, and (3) the nucleation site, which nucleates ZnSe inside the cavity. The characterization of the synthesized ZnSe NPs by X-ray powder diffraction and energy-dispersive spectrometry revealed that the synthesized NPs are a collection of cubic ZnSe polycrystals. It was shown that the 500 degrees C heat treatment for 1 h under nitrogen gas transformed the polycrystalline ZnSe core into a single crystal, and single-crystal ZnSe NPs free of protein were obtained.
In obese individuals, white adipose tissue (WAT) is infiltrated by large numbers of macrophages, resulting in enhanced inflammatory responses that contribute to insulin resistance. Here we show that expression of the CXC motif chemokine ligand-14 (CXCL14), which targets tissue macrophages, is elevated in WAT of obese mice fed a high fat diet (HFD) compared with lean mice fed a regular diet. We found that HFD-fed CXCL14-deficient mice have impaired WAT macrophage mobilization and improved insulin responsiveness. Insulin-stimulated phosphorylation of Akt kinase in skeletal muscle was severely attenuated in HFD-fed CXCL14 ؉/؊ mice but not in HFD-fed CXCL14؊/؊ mice. The insulin-sensitive phenotype of CXCL14 ؊/؊ mice after HFD feeding was prominent in female mice but not in male mice. HFD-fed CXCL14 ؊/؊ mice were protected from hyperglycemia, hyperinsulinemia, and hypoadiponectinemia and did not exhibit increased levels of circulating retinol-binding protein-4 and increased expression of interleukin-6 in WAT. Transgenic overexpression of CXCL14 in skeletal muscle restored obesityinduced insulin resistance in CXCL14 ؊/؊ mice. CXCL14 attenuated insulin-stimulated glucose uptake in cultured myocytes and to a lesser extent in cultured adipocytes. These results demonstrate that CXCL14 is a critical chemoattractant of WAT macrophages and a novel regulator of glucose metabolism that functions mainly in skeletal muscle.
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