VEGFR-3 signaling restrains the neuron-macrophage crosstalk during neurotropic viral infection.

Upon recognizing danger signals produced by virally infected neurons, macrophages in the central nervous system (CNS) secrete multiple inflammatory cytokines to accelerate neuron apoptosis. The understanding is limited about which key effectors regulate macrophage-neuron crosstalk upon infection. We have used neurotropic-virus-infected murine models to identify that vascular endothelial growth factor receptor 3 (VEGFR-3) is upregulated in the CNS macrophages and that virally infected neurons secrete the ligand VEGF-C. When cultured with VEGF-C-containing supernatants from virally infected neurons, VEGFR-3+ macrophages suppress tumor necrosis factor α (TNF-α) secretion to reduce neuron apoptosis. Vegfr-3ΔLBD/ΔLBD (deletion of ligand-binding domain in myeloid cells) mice or mice treated with the VEGFR-3 kinase inhibitor exacerbate the severity of encephalitis, TNF-α production, and neuron apoptosis post Japanese encephalitis virus (JEV) infection. Activating VEGFR-3 or blocking TNF-α can reduce encephalitis and neuronal damage upon JEV infection. Altogether, we show that the inducible VEGF-C/VEGFR-3 module generates protective crosstalk between neurons and macrophages to alleviate CNS viral infection.

Properties of Rigid Polyurethane Foam Modified by Tung Oil-Based Polyol and Flame-Retardant Particles.

Although tung oil is renewable, with an abundant production and low price in China, and it is used to synthesize different polyols for rigid polyurethane foam (RPUF), it remains a challenge to improve the properties of RPUF by redesigning the formula. Therefore, we propose four novel compounds to strengthen the properties of RPUF, such as the catalyst-free synthesis of tung oil-based polyol (PTOK), aluminum phosphate micro-capsule (AM), silica micro-capsule (SiM), and grafted epoxidized monoglyceride of tung oil on the surface of SiO2 (SiE), which were designed and introduced into the RPUF. Because of the PTOK with a catalytic function, the foaming process of some RPUF samples was catalyst-free. The results show that the incorporation of AM, SiM, and SiE, respectively, endow RPUF with a better thermal stability at a high temperature, and the T5%, Tmax1, and Tmax2 of RPUF appeared to be reduced, however, the Tmax3 and residue rate at 800 °C were improved, which may have a positive effect on the extension of the rescue time in case of fire, and the limiting oxygen index (LOI) value was increased to 22.6%. The formula, containing 25% PTOK made the RPUF environment-friendly. The results were obtained by comparing the pore size and mechanical properties of the RPUF-the AM had a better dispersion in the foam, and the foam obtained a better mechanical, thermal, and flame retardancy.