Nitroxyl (HNO) targets phospholamban cysteines 41 and 46 to enhance cardiac function.

Nitroxyl (HNO) positively modulates myocardial function by accelerating Ca2+ reuptake into the sarcoplasmic reticulum (SR). HNO-induced enhancement of myocardial Ca2+ cycling and function is due to the modification of cysteines in the transmembrane domain of phospholamban (PLN), which results in activation of SR Ca2+-ATPase (SERCA2a) by functionally uncoupling PLN from SERCA2a. However, which cysteines are modified by HNO, and whether HNO induces reversible disulfides or single cysteine sulfinamides (RS(O)NH2) that are less easily reversed by reductants, remain to be determined. Using an 15N-edited NMR method for sulfinamide detection, we first demonstrate that Cys46 and Cys41 are the main targets of HNO reactivity with PLN. Supporting this conclusion, mutation of PLN cysteines 46 and 41 to alanine reduces the HNO-induced enhancement of SERCA2a activity. Treatment of WT-PLN with HNO leads to sulfinamide formation when the HNO donor is in excess, whereas disulfide formation is expected to dominate when the HNO/thiol stoichiometry approaches a 1:1 ratio that is more similar to that anticipated in vivo under normal, physiological conditions. Thus, 15N-edited NMR spectroscopy detects redox changes on thiols that are unique to HNO, greatly advancing the ability to detect HNO footprints in biological systems, while further differentiating HNO-induced post-translational modifications from those imparted by other reactive nitrogen or oxygen species. The present study confirms the potential of HNO as a signaling molecule in the cardiovascular system.

A novel bridge wire model of blast traumatic brain injury - biomed 2013.

Research into the mechanics of blast-induced traumatic brain injury requires a device capable of reproducing pressures of the same magnitude and time scale as a blast wave. A blast simulator based on the exploding bridge wire mechanism was created with these capabilities. Peak blast pressures in the range of 5 – 29 psi were generated with a positive phase duration less than 20 µs. A series of experiments using 0.008 inch diameter wires (10-20 psi) were used to demonstrate the ability of the blast simulator to injure in vitro primary brain cell cultures at 1, 24, and 48 hours following blast. Blast exposure caused a rapid loss of cells which was significant over controls. Propidium iodide uptake indicated limited injury to cellular membranes but the cytoskeletal structure showed signs of degeneration 1 hour following blast. These results indicate that the bridge wire blast simulator can serve as a suitable in vitro model of blast injury.