HMGB1 in renal ischemic injury.

Factors that initiate cellular damage and trigger the inflammatory response cascade and renal injury are not completely understood after renal ischemia-reperfusion injury (IRI). High-mobility group box-1 protein (HMGB1) is a damage-associated molecular pattern molecule that binds to chromatin, but upon signaling undergoes nuclear-cytoplasmic translocation and release from cells. Immunohistochemical and Western blot analysis identified HMGB1 nuclear-cytoplasmic translocation and release from renal cells (particularly vascular and tubular cells) into the venous circulation after IRI.

Interaction between uric acid and HMGB1 translocation and release from endothelial cells.

We aimed to investigate the potential relationship between alarmins [acting via Toll-like receptor-4 (TLR4)], uric acid (UA), and high-mobility group box-1 protein (HMGB1) during acute kidney injury. UA, which is significantly increased in the circulation following renal ischemia-reperfusion injury (IRI), was used both in vitro and in vivo as an early response-signaling molecule to determine its ability to induce the secretion of HMGB1 from endothelial cells. Treatment of human umbilical vein endothelial cells (HUVEC) with UA resulted in increased HMGB1 mRNA expression, acetylation of nuclear HMGB1, and its subsequent nuclear-cytoplasmic translocation and release into the circulation, as determined by Western blotting and immunofluorescence.

Mesenchymal stem cells, used as bait, disclose tissue binding sites: a tool in the search for the niche?

We developed an ex vivo approach characterizing renal mesenchymal stem cell (MSC) adhesion to kidney sections. Specificity of MSC adhesion was confirmed by demonstrating a) 3T3 cells displayed 10-fold lower adhesion, and b) MSC adhesion was CXCR4/stromal-derived factor-1 (SDF-1)-dependent. MSC adhesion was asymmetrical, with postischemic sections exhibiting more than twofold higher adhesion than controls, and showed preference to perivascular areas.

Electrochemical release of fluorescently labeled thiols from patterned gold surfaces.

Reductive desorption of alkanethiols is a tool for spatially and temporally controlled release of small molecules or particles from individually addressable gold electrodes. Here we report on the dynamics of release using fluorophore-terminated C6 or C11 thiols. We show that the release kinetics for C6 thiols are determined solely by diffusive transport, whereas for C11 thiols the release kinetics are attenuated by the low solubility that limits the rate at which the desorbed thiols can diffuse away from the surface.