The photophysics and photochemistry of rose bengal (RB) and methylene blue (MB) bound to human serum albumin (HSA) have been investigated under a variety of experimental conditions. Distribution of the dyes between the external solvent and the protein has been estimated by physical separation and fluorescence measurements. The main localization of protein-bound dye molecules was estimated by the intrinsic fluorescence quenching, displacement of fluorescent probes bound to specific protein sites, and by docking modelling. All the data indicate that, at low occupation numbers, RB binds strongly to the HSA site I, while MB localizes predominantly in the protein binding site II. This different localization explains the observed differences in the dyes' photochemical behaviour. In particular, the environment provided by site I is less polar and considerably less accessible to oxygen. The localization of RB in site I also leads to an efficient quenching of the intrinsic protein fluorescence (ascribed to the nearby Trp residue) and the generation of intra-protein singlet oxygen, whose behaviour is different to that observed in the external solvent or when it is generated by bound MB.

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NOD1 is an intracellular receptor that, when activated, induces gene expression of pro-inflammatory factors promoting macrophages and neutrophils recruitment at the infection site. However, iE-DAP, the dipeptide agonist that promotes this receptor's activation, cannot permeate cell membranes. To develop a nanocarrier capable of achieving a high and prolonged activation over time, iE-DAP was encapsulated in nanoparticles (NPs) made of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). The physicochemical properties, colloidal stability, encapsulation efficiency, and cellular uptake of iE-DAP-loaded PHVB NPs were analyzed. Results evidenced that physicochemical properties of iE-DAP-loaded NPs remained stable over time, and NPs were efficiently internalized into cells, a process that depends on time and concentration. Moreover, our results showed that NPs elicited a controlled cargo release in vitro , and the encapsulated agonist response was higher than its free form, suggesting the possibility of activating intracellular receptors triggering an immune response through the release of NOD1 agonist.

in myocytes from basilar arteries; 4) myocyte BK channels in basilar arteries show the highest response to lithocholate; 5) lithocholate-induced dilation of basilar arteries is significantly higher than those measured in other intracranial territories. Collectively, our results demonstrate differential BK b1 expression, as well as its contribution to BK current phenotype and vasodilation by lithocholate, across the major branches of the Willis' circle. In particular, basilar arteries seem to be highly sensitive to vasoactive agents that act via BK b1 subunits. Support: HL104631 and AA11560 (AMD), and AHA Predoctoral Fellowship (GK).