Seminar series
Fri, Sep 1 12:00pm
Molecular Sciences 3440
Speaker Dr. Roland Stocker
Victor Chang Cardiac Research Institute

"Singlet molecular oxygen regulates vascular tone and blood pressure in inflammation" by Dr. Roland Stocker  Victor Chang Cardiac Research Institute, Sydney, NSW Australia  Abstract. Singlet molecular oxygen (1O2) has well-established biological roles in plants, photosynthetic bacteria, some fungi, but not in mammals. We show here that 1O2 is formed by indoleamine 2,3-dioxygenase 1 in the vascular endothelium under inflammatory conditions and that this is associated with the stereo-selective oxidation of l-tryptophan to a tricyclic hydroperoxide via a previously unrecognized oxidative dioxygenase activity. The tryptophan-derived hydroperoxide then acts as a signaling molecule, inducing relaxation of arteries from different species and decreasing blood pressure in mice. This activity is dependent on a specific cysteine residue (cysteine-42) of protein kinase G1a. Our findings indicate, for the first time, a (patho)physiological function for 1O2 in mammals via formation of a signaling molecule that regulates vascular tone and blood pressure during acute systemic inflammation.  Friday, September 1, 2017 at 12:00 p.m. Molecular Sciences 3440