Deficits in cognitive function are associated with neuroinflammatory changes, typified by activation of glial cells and an alteration of the pro-and anti-inflammatory cytokine balance in the brain. Although there is evidence to suggest that activation of microglia is regulated by interaction with other cell types in the brain, the mechanism(s) involved is poorly understood. Here, we provide evidence that interaction between CD200 and its receptor plays a role in modulating microglial activation under conditions of chronic and acute inflammation of the brain. We report that interleukin-4 (IL-4) plays a central role in modulating expression of CD200 and identify a mechanism by which IL-4 directly controls microglial cell activation. Our findings provide the first demonstration of a role for IL-4 in modulating CD200 expression and suggest a mechanism for regulation of microglial activation in the intact CNS under inflammatory conditions.

Several neurodegenerative disorders are associated with evidence of inflammation, one feature of which is increased activation of microglia, the most likely cellular source of inflammatory cytokines like interleukin‐1β. It is now recognized that interaction of microglia with other cells contributes to maintenance of microglia in a quiescent state and the complementary distribution of the chemokine, fractalkine (CX3CL1) on neurons and its receptor (CX3CR1) on microglia, suggests that this interaction may play a role in modulating microglial activation. Here we demonstrate that both soluble and membrane‐bound fractalkine attenuate lipopolysaccharide‐induced microglial activation in vitro. We also show that fractalkine expression is reduced in the brain of aged rats and this is accompanied by an age‐related increase in microglial activation. Treatment of aged rats with fractalkine attenuates the age‐related increase in microglial activation and the evidence indicates that fractalkine‐induced activation of the phosphatidylinositol‐3 kinase pathway is required to maintain microglia in a quiescent state both in vivo and in vitro.

This Article describes the synthesis and physicomechanical properties of bioplastics prepared from methyl ω-hydroxytetradecanoic acid (Me-ω-OHC14), a new monomer available by a fermentation process using an engineered Candida tropicalis strain. Melt-condensation experiments were conducted using titanium tetraisopropoxide (Ti[OiPr](4)) as a catalyst in a two-stage polymerization (2 h at 200 °C under N(2), 4 h at 220 °C under 0.1 mmHg). Poly(ω-hydroxytetradecanoate), P(ω-OHC14), M(w), determined by SEC-MALLS, increased from 53K to 110K as the Ti(OiPr)(4) concentration increased from 50 to 300 ppm. By varying the polymerization conditions (catalyst concentration, reaction time, second-stage reaction temperature) a series of P(ω-OHC14) samples were prepared with M(w) values from 53K to 140K. The synthesized polyesters with M(w) ranging from 53K to 140K were subjected to characterization by DSC, TGA, DMTA, and tensile testing. Influences of P(ω-OHC14) molecular weight, melting point, and enthalpies of melting/crystallization on material tensile properties were explored. Cold-drawing tensile tests at room temperature for P(ω-OHC14) with M(w) 53K-78K showed a brittle-to-ductile transition. In contrast, P(ω-OHC14) with M(w) 53K undergoes brittle fracture. Increasing P(ω-OHC14) M(w) above 78K resulted in a strain-hardening phenomena and tough properties with elongation at break ~700% and true tensile strength of ~50 MPa. Comparisons between high density polyethylene and P(ω-OHC14) mechanical and thermal properties as a function of their respective molecular weights are discussed.

The membrane glycoprotein CD200 is expressed on several cell types, including neurons, whereas expression of its receptor, CD200R, is restricted principally to cells of the myeloid lineage, including microglia. The interaction between CD200 and CD200R maintains microglia and macrophages in a quiescent state; therefore, CD200-deficient mice express an inflammatory phenotype exhibiting increased macrophage or microglial activation in models of arthritis, encephalitis, and uveoretinitis. Here, we report that lipopolysaccharide (

Multifunctional superhydrophobic nanocomposite surfaces based on photocatalytic materials, such as fluorosilane modified TiO2, have generated significant research interest. However, there are two challenges to forming such multifunctional surfaces with stable superhydrophobic properties: the photocatalytic oxidation of the hydrophobic functional groups, which leads to the permanent loss of superhydrophobicity, as well as the photoinduced reversible hydrolysis of the catalytic particle surface. Herein, we report a simple and inexpensive template lamination method to fabricate multifunctional TiO2-high-density polyethylene (HDPE) nanocomposite surfaces exhibiting superhydrophobicity, UV-induced reversible wettability, and self-cleaning properties. The laminated surface possesses a hierarchical roughness spanning the micro- to nanoscale range. This was achieved by using a wire mesh template to emboss the HDPE surface creating an array of polymeric posts while partially embedding untreated TiO2 nanoparticles selectively into the top surface of these features. The surface exhibits excellent superhydrophobic properties immediately after lamination without any chemical surface modification to the TiO2 nanoparticles. Exposure to UV light causes the surface to become hydrophilic. This change in wettability can be reversed by heating the surface to restore superhydrophobicity. The effect of TiO2 nanoparticle surface coverage and chemical composition on the mechanism and magnitude of wettability changes was studied by EDX and XPS. In addition, the ability of the surface to shed impacting water droplets as well as the ability of such droplets to clean away particulate contaminants was demonstrated.

It has been shown that Ab inhibits long-term potentiation (LTP) in the rat hippocampus and this is accompanied by an increase in hippocampal concentration of IL-1b. Ab also increases microglial activation, which is the likely cell source of IL-1b. Because IL-4 attenuates the effects of IL-1b in hippocampus, and microglial activation is inhibited by minocycline, we assessed the ability of both IL-4 and minocycline to modulate the effects of Ab on LTP and IL-1b concentration. Following treatment with Ab, IL-4 or minocycline, rats were assessed for their ability to sustain LTP in perforant pathgranule cell synapses. We report that the Ab-induced inhibition of LTP was associated with increases in expression of MHCII, JNK phosphorylation and IL-1b concentration, and that these changes were attenuated by treatment of rats with IL-4 and minocycline. We also report that Ab-induced increases in expression of MHCII and IL-1b were similarly attenuated by IL-4 and minocycline in glial cultures prepared from neonatal rats. These data suggest that glial cell activation and the consequent increase in IL-1b concentration mediate the inhibitory effect of Ab on LTP and indicate that IL-4, by downregulating glial cell activation, antagonizes the effects of Ab. Keywords: Amyloid-b (Ab), interleukin-1b (IL-1b), interleukin-4 (IL-4), Long-term potentiation (LTP), microglial activation, minocycline.

Fabricating robust superhydrophobic surfaces for commercial applications is challenging as the fine-scale surface features, necessary to achieve superhydrophobicity, are susceptible to mechanical damage. Herein, we report a simple and inexpensive lamination templating method to create superhydrophobic polymer surfaces with excellent abrasion resistance and water pressure stability. To fabricate the surfaces, polyethylene films were laminated against woven wire mesh templates. After cooling, the mesh was peeled from the polymer creating a 3D array of ordered polymer microposts on the polymer surface. The resulting texture is monolithic with the polymer film and requires no chemical modification to exhibit superhydrophobicity. By controlling lamination parameters and mesh dimensions, polyethylene surfaces were fabricated that exhibit static contact angles of 160° and slip angles of 5°. Chemical and mechanical stability was evaluated using an array of manual tests as well as a standard reciprocating abraser test. Surfaces remained superhydrophobic after more than 5500 abrasion cycles at a pressure of 32.0 kPa. In addition, the surface remains dry after immersing into water for 5 h at 55 kPa. This method is environmental friendly, as it employs no solvents or harsh chemicals and may provide an economically viable path to manufacture large areas of mechanically robust superhydrophobic surfaces from inexpensive polymers and reusable templates.

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